Science.gov

Sample records for current resistivity evaluation

  1. Method for the formation of cylindrical current and its application to evaluate electrical resistivity

    NASA Astrophysics Data System (ADS)

    Li, T.-C.; Chang, C.-S.; Liang, W.-L.; Tsai, W.-F.; Ai, C.-F.; Lin, J.-F.

    2012-07-01

    A cylindrical current method is developed to obtain a stable and precise electrical resistivity of a specimen with or without a coating film. The electrical resistivity of a standard silicon wafer doped with boron at a concentration can be measured using the proposed method if the experimental results of electrical voltage varying with the distance from the center line of the cylindrical current are available. A comparison of the electrical resistivity obtained using the present method and the theoretical reference value indicates that the proposed method produces reliable and precise measurements. Using four test samples, the experimental results of electrical resistivity measured by the present method are shown to be reproducible and more precise than those measured by the four-terminal sensing method and the van der Pauw method. The electrical voltage and current obtained at various distances from the center line of the cylindrical current are almost independent of the distance and the direction of measurements. The effect of specimen's crystallinity appears to be the governing factor of electrical resistivity. Electrical resistivity decreases with increasing crystallinity generally.

  2. Ground penetrating radar and direct current resistivity evaluation of the desiccation test cap, Savannah River Site

    SciTech Connect

    Wyatt, D.E.; Cumbest, R.J.

    1996-04-01

    The Savannah River Site (SRS) has a variety of waste units that may be temporarily or permanently stabilized by closure using an impermeable cover to prevent groundwater infiltration. The placement of an engineered kaolin clay layer over a waste unit is an accepted and economical technique for providing an impermeable cover but the long term stability and integrity of the clay in non-arid conditions is unknown. A simulated kaolin cap has been constructed at the SRA adjacent to the Burial Ground Complex. The cap is designed to evaluate the effects of desiccation on clay integrity, therefore half of the cap is covered with native soil to prevent drying, while the remainder of the cap is exposed. Measurements of the continuing impermeability of a clay cap are difficult because intrusive techniques may locally compromise the structure. Point measurements made to evaluate clay integrity, such as those from grid sampling or coring and made through a soil cover, may miss cracks, joints or fissures, and may not allow for mapping of the lateral extent of elongate features. Because of these problems, a non-invasive technique is needed to map clay integrity, below a soil or vegetation cover, which is capable of moderate to rapid investigation speeds. Two non-intrusive geophysical techniques, direct current resistivity and ground penetrating radar (GPR), have been successful at the SRS in geologically mapping shallow subsurface clay layers. The applicability of each technique in detecting the clay layer in the desiccation test cap and associated anomalies was investigated.

  3. Reversal of ABC drug transporter-mediated multidrug resistance in cancer cells: Evaluation of current strategies

    PubMed Central

    Wu, Chung-Pu; Calcagno, Anna Maria; Ambudkar, Suresh V.

    2008-01-01

    Overexpression of ATP-binding cassette (ABC) drug transporters that actively efflux a variety of amphipathic compounds can cause multidrug resistance (MDR) in cancer cells, which is a major obstacle in the success of cancer chemotherapy. The development of synthetic small molecule compounds or the identification of natural products that block ABC transporter-mediated efflux has been the conventional approach used to combat MDR. The strategy of using chemosensitizers, however, has not been successful in clinical cancer chemotherapy. Therefore, alternative approaches to identify or to synthesize compounds that can induce selective toxicity in cancer cells overexpressing one or more ABC transporters have been undertaken. This review summarizes the recent advances in identifying strategies to restore sensitivity to chemotherapeutics in multidrug resistant cancer cells. PMID:19079736

  4. Current perspectives on glycopeptide resistance.

    PubMed Central

    Woodford, N; Johnson, A P; Morrison, D; Speller, D C

    1995-01-01

    In the last 5 years, clinical isolates of gram-positive bacteria with intrinsic or acquired resistance to glycopeptide antibiotics have been encountered increasingly. In many of these isolates, resistance arises from an alteration of the antibiotic target site, with the terminal D-alanyl-D-alanine moiety of peptidoglycan precursors being replaced by groups that do not bind glycopeptides. Although the criteria for defining resistance have been revised frequently, the reliable detection of low-level glycopeptide resistance remains problematic and is influenced by the method chosen. Glycopeptide-resistant enterococci have emerged as a particular problem in hospitals, where in addition to sporadic cases, clusters of infections with evidence of interpatient spread have occurred. Studies using molecular typing methods have implicated colonization of patients, staff carriage, and environmental contamination in the dissemination of these bacteria. Choice of antimicrobial therapy for infections caused by glycopeptide-resistant bacteria may be complicated by resistance to other antibiotics. Severe therapeutic difficulties are being encountered among patients infected with enterococci, with some infections being untreatable with currently available antibiotics. PMID:8665471

  5. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    NASA Astrophysics Data System (ADS)

    Segal, Christopher; Tarantini, Chiara; Hawn Sung, Zu; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-08-01

    High critical current density (J c) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain (SG), superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In powder-in-tube (PIT) wires the unreacted Nb7.5 wt%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this study we investigate recent high quality PIT wires that achieve a J c (12 T, 4.2 K) up to ˜2500 A mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ˜1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible J c must be addressed by forming the maximum fraction of high J c SG A15 and minimizing low J c large-grain (LG) A15 morphologies. In one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial J c improvement.

  6. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    DOE PAGES

    Segal, Christopher; Tarantini, Chiara; Sung, Zu Hawn; ...

    2016-06-10

    High critical current density (Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain, superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In Powder-in-Tube (PIT) wires the unreacted Nb7.5wt.%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment (HT) to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this paper we investigate recent highmore » quality PIT wires that achieve a Jc(12 T, 4.2 K) up to ~2500 A/mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ~1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible Jc must be addressed by forming the maximum fraction of high Jc small-grain (SG) A15 and minimizing low Jc large-grain (LG) A15 morphologies. Finally, in one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial Jc improvement.« less

  7. Resistance to AHAS inhibitor herbicides: current understanding.

    PubMed

    Yu, Qin; Powles, Stephen B

    2014-09-01

    Acetohydroxyacid synthase (AHAS) inhibitor herbicides currently comprise the largest site-of-action group (with 54 active ingredients across five chemical groups) and have been widely used in world agriculture since they were first introduced in 1982. Resistance evolution in weeds to AHAS inhibitors has been rapid and identified in populations of many weed species. Often, evolved resistance is associated with point mutations in the target AHAS gene; however non-target-site enhanced herbicide metabolism occurs as well. Many AHAS gene resistance mutations can occur and be rapidly enriched owing to a high initial resistance gene frequency, simple and dominant genetic inheritance and lack of major fitness cost of the resistance alleles. Major advances in the elucidation of the crystal structure of the AHAS (Arabidopsis thaliana) catalytic subunit in complex with various AHAS inhibitor herbicides have greatly improved current understanding of the detailed molecular interactions between AHAS, cofactors and herbicides. Compared with target-site resistance, non-target-site resistance to AHAS inhibitor herbicides is less studied and hence less understood. In a few well-studied cases, non-target-site resistance is due to enhanced rates of herbicide metabolism (metabolic resistance), mimicking that occurring in tolerant crop species and often involving cytochrome P450 monooxygenases. However, the specific herbicide-metabolising, resistance-endowing genes are yet to be identified in resistant weed species. The current state of mechanistic understanding of AHAS inhibitor herbicide resistance is reviewed, and outstanding research issues are outlined.

  8. Subsurface evaluation of the west parking lot and landfill 3 areas of Air Force Plant 4, Fort Worth, Texas, using two-dimensional direct-current resistivity profiling

    USGS Publications Warehouse

    Braun, Christopher L.; Jones, Sonya A.

    2002-01-01

    During September 1999, the U.S. Geological Survey made 10 two-dimensional direct-current resistivity profile surveys in the west parking lot and landfill 3 areas of Air Force Plant 4, Fort Worth, Texas, to identify subsurface areas of anomalously high or low resistivity that could indicate potential contamination, contaminant pathways, or anthropogenic structures. Six of the 10 surveys (transects) were in the west parking lot. Each of the inverted sections of these transects had anomalously high resistivities in the terrace alluvium/fill (the surficial subsurface layer) that probably were caused by highly resistive fill material. In addition, each of these transects had anomalously low resistivities in the Walnut Formation (a bedrock layer immediately beneath the alluvium/fill) that could have been caused by saturation of fractures within the Walnut Formation. A high-resistivity anomaly in the central part of the study area probably is associated with pea gravel fill used in construction of a French drain. Another high resistivity anomaly in the west parking lot, slightly southeast of the French drain, could be caused by dense nonaqueous-phase liquid in the Walnut Formation. The inverted sections of the four transects in the landfill 3 area tended to have slightly higher resistivities in both the alluvium/fill and the Walnut Formation than the transects in the west parking lot. The higher resistivities in the alluvium/fill could have been caused by drier conditions in grassy areas relative to conditions in the west parking lot. Higher resistivities in parts of the Walnut Formation also could be a function of drier conditions or variations in the lithology of the Walnut Formation. In addition to the 10 vertical sections, four horizontal sections at 2-meteraltitude intervals show generally increasing resistivity with decreasing altitude that most likely results from the increased influence of the Walnut Formation, which has a higher resistivity than the terrace

  9. Current Understandings of Plant Nonhost Resistance.

    PubMed

    Lee, Hyun-Ah; Lee, Hye-Young; Seo, Eunyoung; Lee, Joohyun; Kim, Saet-Byul; Oh, Soohyun; Choi, Eunbi; Choi, Eunhye; Lee, So Eui; Choi, Doil

    2017-01-01

    Nonhost resistance, a resistance of plant species against all nonadapted pathogens, is considered the most durable and efficient immune system of plants but yet remains elusive. The underlying mechanism of nonhost resistance has been investigated at multiple levels of plant defense for several decades. In this review, we have comprehensively surveyed the latest literature on nonhost resistance in terms of preinvasion, metabolic defense, pattern-triggered immunity, effector-triggered immunity, defense signaling, and possible application in crop protection. Overall, we summarize the current understanding of nonhost resistance mechanisms. Pre- and postinvasion is not much deviated from the knowledge on host resistance, except for a few specific cases. Further insights on the roles of the pattern recognition receptor gene family, multiple interactions between effectors from nonadapted pathogen and plant factors, and plant secondary metabolites in host range determination could expand our knowledge on nonhost resistance and provide efficient tools for future crop protection using combinational biotechnology approaches. [Formula: see text] Copyright © 2017 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

  10. Resistive-Type Fault Current Limiter

    NASA Astrophysics Data System (ADS)

    Martini, L.; Bocchi, M.; Angeli, G.

    Among the wide range of High-Temperature Superconducting (HTS) materials presently known Bismuth Strontium Calcium Copper Oxide (BSCCO) is a very suitable candidate for power applications either at low temperature (e.g. <30K) at any field or at high temperature (e.g. 77K) in self-field conditions. This is due to several advantages of BSCCO from an electrical, thermal, mechanical and economic point of view. In particular, BSCCO has been proven to be particularly suitable for hybrid current leads and HTS cables. However, BSCCO-based Superconducting Fault Current Limiter (SFCL) applications have been an important issue within the Ricerca sul Sistema Energetico (RSE) S.p.A. R&D portfolio in the last decade. The SFCL project, funded in the framework of a R&D national project, started focusing on a preliminary single-phase device, which was submitted to dielectric and short-circuit current testing. The first success paved the way for the finalization of the remaining two phases and the final result was a three-phase resistive-type 9 kV/3.4 MVA SFCL device, based on first generation (1G) BSCCO tapes that was installed in the S. Dionigi substation, belonging to the Italian utility A2A Reti Elettriche S.p.A. (A2A), in the Milan MV distribution grid. The in-field activity lasted for more than two years, demonstrating the SFCL capability to cope with the grid in every-day operating conditions. Moreover, at the end of the experimentation, the SFCL device was able to perform a true limitation during a three-phase fault, thereby becoming one of the first SFCL devices in the world (the first in Italy) installed in a real grid and to have limited a real short-circuit current.

  11. Evaluation of critical current density and residual resistance ratio limits in powder in tube Nb3Sn conductors

    SciTech Connect

    Segal, Christopher; Tarantini, Chiara; Sung, Zu Hawn; Lee, Peter J.; Sailer, Bernd; Thoener, Manfred; Schlenga, Klaus; Ballarino, Amalia; Bottura, Luca; Bordini, Bernardo; Scheuerlein, Christian; Larbalestier, David C.

    2016-06-10

    High critical current density (Jc) Nb3Sn A15 multifilamentary wires require a large volume fraction of small grain, superconducting A15 phase, as well as Cu stabilizer with high Residual Resistance Ratio (RRR) to provide electromagnetic stabilization and protection. In Powder-in-Tube (PIT) wires the unreacted Nb7.5wt.%Ta outer layer of the tubular filaments acts as a diffusion barrier and protects the interfilamentary Cu stabilizer from Sn contamination. A high RRR requirement generally imposes a restricted A15 reaction heat treatment (HT) to prevent localized full reaction of the filament that could allow Sn to reach the Cu. In this paper we investigate recent high quality PIT wires that achieve a Jc(12 T, 4.2 K) up to ~2500 A/mm-2 and find that the minimum diffusion barrier thickness decreases as the filament aspect ratio increases from ~1 in the inner rings of filaments to 1.3 in the outer filament rings. We found that just 2-3 diffusion barrier breaches can degrade RRR from 300 to 150 or less. Using progressive etching of the Cu we also found that the RRR degradation is localized near the external filaments where deformation is highest. Consequently minimizing filament distortion during strand fabrication is important for reducing RRR degradation. The additional challenge of developing the highest possible Jc must be addressed by forming the maximum fraction of high Jc small-grain (SG) A15 and minimizing low Jc large-grain (LG) A15 morphologies. Finally, in one wire we found that 15% of the filaments had a significantly enhanced SG/LG A15 ratio and no residual A15 in the core, a feature that opens a path to substantial Jc improvement.

  12. Evaluation of platinum resistance thermometers

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Dillon-Townes, Lawrence A.

    1988-01-01

    An evaluation procedure for the characterization of industrial platinum resistance thermometers (PRTs) for use in the temperature range -120 to 160 C was investigated. This evaluation procedure consisted of calibration, thermal stability and hysteresis testing of four surface measuring PRTs. Five different calibration schemes were investigated for these sensors. The IPTS-68 formulation produced the most accurate result, yielding average sensor systematic error of 0.02 C and random error of 0.1 C. The sensors were checked for thermal stability by successive and thermal cycling between room temperature, 160 C, and boiling point of nitrogen. All the PRTs suffered from instability and hysteresis. The applicability of the self-heating technique as an in situ method for checking the calibration of PRTs located inside wind tunnels was investigated.

  13. Constant-Current Source For Measuring Low Resistances

    NASA Technical Reports Server (NTRS)

    Toomath, Robert L.

    1996-01-01

    Constant-current source constructed for measuring electrical resistances up to few ohms in power-supply equipment. By setting current at 1 A and measuring resulting voltage drop across item under test, one obtains voltage reading numerically equal to resistance in ohms.

  14. Evaluation in Education: Current Applications.

    ERIC Educational Resources Information Center

    Popham, W. James, Ed.

    Representing a set of required readings for those who would keep abreast of developments in the field of educational evaluation, this book presents nine chapters, each written by a recognized scholar on the topic being considered. Several chapters are also available as separate booklets, thereby increasing the flexibility with which the materials…

  15. DESIGN NOTE: A very high output resistance current source

    NASA Astrophysics Data System (ADS)

    Hayatleh, K.; Terzopoulos, N.; Hart, B. L.

    2007-01-01

    The vertical stacking of two identical sub-circuits—improved versions of a bipolar transistor configuration proposed by Baxandall and Swallow—driven by dual output current mirrors, facilitates the design of a current generator producing a direct current of 1 mA with an incremental output resistance exceeding 200 GΩ.

  16. Linear waves in a resistive plasma with Hall current

    SciTech Connect

    Almaguer, J.A. )

    1992-10-01

    Dispersion relations for the case of a magnetized plasma are determined taking into account the Hall current and a constant resistivity, {eta}, in Ohm's law. It is found that the Hall effect is relevant only for parallel (to the equilibrium magnetic field) wave numbers in the case of uniform plasmas, giving place to a dispersive behavior. In particular, the cases of {eta}{r arrow}0 and small (nonzero) resistivity are discussed.

  17. Current state of herbicides in herbicide-resistant crops.

    PubMed

    Green, Jerry M

    2014-09-01

    Current herbicide and herbicide trait practices are changing in response to the rapid spread of glyphosate-resistant weeds. Growers urgently needed glyphosate when glyphosate-resistant crops became available because weeds were becoming widely resistant to most commonly used selective herbicides, making weed management too complex and time consuming for large farm operations. Glyphosate made weed management easy and efficient by controlling all emerged weeds at a wide range of application timings. However, the intensive use of glyphosate over wide areas and concomitant decline in the use of other herbicides led eventually to the widespread evolution of weeds resistant to glyphosate. Today, weeds that are resistant to glyphosate and other herbicide types are threatening current crop production practices. Unfortunately, all commercial herbicide modes of action are over 20 years old and have resistant weed problems. The severity of the problem has prompted the renewal of efforts to discover new weed management technologies. One technology will be a new generation of crops with resistance to glyphosate, glufosinate and other existing herbicide modes of action. Other technologies will include new chemical, biological, cultural and mechanical methods for weed management. From the onset of commercialization, growers must now preserve the utility of new technologies by integrating their use with other weed management technologies in diverse and sustainable systems.

  18. Resistive current state of a wide superconducting film

    NASA Astrophysics Data System (ADS)

    Zolochevskii, I. V.

    2011-12-01

    The current-voltage characteristics (CVCs) of vortex superconducting films are investigated in a wide temperature range. It is shown for the first time that the experimental CVCs and their parameters are described well enough by asymptotic formulas within the theory of the vortex resistive state of Aslamazov-Lempitsky (AL). It is established that for wide films, the critical current of which corresponds to the AL theory, the differential resistance of a linear segment of a CVC does not depend on temperature that agrees with the model of the vortex resistive state of AL. In the range of much higher temperatures, where the critical current is Ic(T)∝(1-T/Tc)3/2, the decrease of the differential resistance with increasing the temperature is observed that corresponds to predictions of the AL theory. However, in the close vicinity of Tc the increase of the differential resistance of a linear vortex segment of CVCs was found at T → Tc. This effect does not have an explanation in modern theories of a vortex state.

  19. Insulin resistance modifies the association between obesity and current asthma in adults.

    PubMed

    Cardet, Juan Carlos; Ash, Samuel; Kusa, Tope; Camargo, Carlos A; Israel, Elliot

    2016-08-01

    Insulin resistance potentiates the association between obesity and childhood asthma, but this relationship appears inconsistent in relatively small studies of adults. We investigated effect modification in adults using the National Health and Nutrition Examination Survey 2003-2012, a large, nationally representative database.Insulin resistance and a history of physician-diagnosed current asthma were obtained from 12 421 adults, ages 18-85 years. We used logistic regression to determine associations between obesity and current asthma, adjusting for age, sex, race/ethnicity, poverty income ratio and smoking status. An interaction term evaluated effect modification by insulin resistance of the obesity-asthma association.As expected, obesity was positively associated with current asthma. Insulin resistance modified this association, with obesity measured as body mass index, waist circumference or waist-to-height ratio. The relationship between obesity and current asthma was stronger with increasing insulin resistance tertiles (OR 2.05, 95% CI 2.76-3.00; p-value for interaction 0.03). This association was robust to adjustments for other components of the metabolic syndrome (hypertriglyceridaemia, hypertension, hyperglycaemia and systemic inflammation). None of these components were themselves effect modifiers of the obesity-asthma association.In this large, nationally representative sample, insulin resistance modified the association between obesity and current asthma in adults. Targeting insulin resistance may represent a novel therapeutic strategy for obese patients with asthma.

  20. Overcoming treatment resistance in cancer: Current understanding and tactics.

    PubMed

    Wu, Guang; Wilson, George; George, Jacob; Liddle, Christopher; Hebbard, Lionel; Qiao, Liang

    2017-02-28

    Chemotherapy is the standard treatment for many, if not all, metastatic cancers. While chemotherapy is often capable of inducing cell death in tumors leading to shrinkage of the tumor bulk, many patients suffer from recurrence and ultimately death due to resistance. During the last decade, treatment resistance has attracted great attention followed by some seminal discoveries, including sequential mutations, cancer stem cells, and bidirectional inter-conversion of stem and non-stem cancer cell populations. Nevertheless, the successful treatment of cancer will require a considerable refinement of our knowledge concerning treatment resistance. In doing so, we expect that a more informed and refined approach to treat cancer will be developed and this may improve prognosis of cancer patients. In this review, we will discuss the current knowledge concerning the failure of cancer treatments and the potential approaches to overcome therapeutic resistance.

  1. Resistivity and anisotropic return currents in warm dense plasmas

    NASA Astrophysics Data System (ADS)

    Woolsey, Nigel; Booth, Nicola; Robinson, A.; Hakel, P.; Clarke, R.; Dance, R.; Doia, D.; Gizzi, L.; Gregori, G.; Koester, P.; Labate, L.; Li, B.; Makita, M.; Mancini, R.; Pasley, J.; Rajeev, P.; Riley, D.; Wagenaars, E.; Waugh, J.

    2015-11-01

    In an ultra-intense laser interaction with a solid, the electrons from the hot plasma are accelerated by the laser streaming into the solid behind, creating a dense plasma in the bulk. This provides a laboratory for creating warm dense matter in a parameter range where the material resistivity and equation of states are complex and mostly untested. Here we describe an experimental study of electron transport in a low atomic number (plastic) material at solid density and temperatures of 200 eV. The plastic is doped with sulphur as a diagnostic tracer to enable the observation of emission spectra. Through observing high positive polarisation in this emission it is possible to infer in situ anisotropic currents driving the heat transport. Matching the current anisotropy enables tests of resistivity models in these complex plasmas. Results show that the background resistivity at these conditions is high than expected from commonly used models.

  2. Proliferation resistance: issues, initiatives and evaluation

    SciTech Connect

    Pilat, Joseph F

    2009-01-01

    The vision of a nuclear renaissance has highlighted the issue of proliferation resistance. The prospects for a dramatic growth in nuclear power may depend on the effectiveness of, and the resources devoted to, plans to develop and implement technologies and approaches that strengthen proliferation resistance. The GenIV International Forum (GIF) and others have devoted attention and resources to proliferation resistance. However, the hope of finding a way to make the peaceful uses of nuclear energy resistant to proliferation has reappeared again and again in the history of nuclear power with little practical consequence. The concept of proliferation resistance has usually focused on intrinsic (technological) as opposed to extrinsic (institutional) factors. However, if there are benefits that may yet be realized from reactors and other facilities designed to minimize proliferation risks, it is their coupling with effective safeguards and other nonproliferation measures that likely will be critical. Proliferation resistance has also traditionally been applied only to state threats. Although there are no technologies that can wholly eliminate the risk of proliferation by a determined state, technology can play a limited role in reducing state threats and perhaps in eliminating many non-state threats. These and other issues are not academic. They affect efforts to evaluate proliferation resistance, including the methodology developed by GIF's Proliferation Resistance and Physical Protection (PR&PP) Working Group as well as the proliferation resistance initiatives that are being pursued or may be developed in the future. This paper will offer a new framework for thinking about proliferation resistance issues, including the ways the output of the methodology could be developed to inform the decisions that states, the International Atomic Energy (IAEA) and others will have to make in order to fully realize the promise of a nuclear renaissance.

  3. Electron viscosity, current vortices and negative nonlocal resistance in graphene

    NASA Astrophysics Data System (ADS)

    Levitov, Leonid; Falkovich, Gregory

    2016-07-01

    Quantum-critical strongly correlated electron systems are predicted to feature universal collision-dominated transport resembling that of viscous fluids. However, investigation of these phenomena has been hampered by the lack of known macroscopic signatures of electron viscosity. Here we identify vorticity as such a signature and link it with a readily verifiable striking macroscopic d.c. transport behaviour. Produced by the viscous flow, vorticity can drive electric current against an applied field, resulting in a negative nonlocal voltage. We argue that the latter may play the same role for the viscous regime as zero electrical resistance does for superconductivity. Besides offering a diagnostic that distinguishes viscous transport from ohmic currents, the sign-changing electrical response affords a robust tool for directly measuring the viscosity-to-resistivity ratio. A strongly interacting electron-hole plasma in high-mobility graphene affords a unique link between quantum-critical electron transport and the wealth of fluid mechanics phenomena.

  4. Resistive coating for current conductors in cryogenic applications

    DOEpatents

    Hirayama, Chikara; Wagner, George R.

    1982-05-18

    This invention relates to a resistive or semiconducting coating for use on current conductors in cryogenic applications. This includes copper-clad superconductor wire, copper wire used for stabilizing superconductor magnets, and for hyperconductors. The coating is a film of cuprous sulfide (Cu.sub.2 S) that has been found not to degrade the properties of the conductors. It is very adherent to the respective conductors and satisfies the mechanical, thermal and electrical requirements of coatings for the conductors.

  5. Emerging memories: resistive switching mechanisms and current status.

    PubMed

    Jeong, Doo Seok; Thomas, Reji; Katiyar, R S; Scott, J F; Kohlstedt, H; Petraru, A; Hwang, Cheol Seong

    2012-07-01

    The resistance switching behaviour of several materials has recently attracted considerable attention for its application in non-volatile memory (NVM) devices, popularly described as resistive random access memories (RRAMs). RRAM is a type of NVM that uses a material(s) that changes the resistance when a voltage is applied. Resistive switching phenomena have been observed in many oxides: (i) binary transition metal oxides (TMOs), e.g. TiO(2), Cr(2)O(3), FeO(x) and NiO; (ii) perovskite-type complex TMOs that are variously functional, paraelectric, ferroelectric, multiferroic and magnetic, e.g. (Ba,Sr)TiO(3), Pb(Zr(x) Ti(1-x))O(3), BiFeO(3) and Pr(x)Ca(1-x)MnO(3); (iii) large band gap high-k dielectrics, e.g. Al(2)O(3) and Gd(2)O(3); (iv) graphene oxides. In the non-oxide category, higher chalcogenides are front runners, e.g. In(2)Se(3) and In(2)Te(3). Hence, the number of materials showing this technologically interesting behaviour for information storage is enormous. Resistive switching in these materials can form the basis for the next generation of NVM, i.e. RRAM, when current semiconductor memory technology reaches its limit in terms of density. RRAMs may be the high-density and low-cost NVMs of the future. A review on this topic is of importance to focus concentration on the most promising materials to accelerate application into the semiconductor industry. This review is a small effort to realize the ambitious goal of RRAMs. Its basic focus is on resistive switching in various materials with particular emphasis on binary TMOs. It also addresses the current understanding of resistive switching behaviour. Moreover, a brief comparison between RRAMs and memristors is included. The review ends with the current status of RRAMs in terms of stability, scalability and switching speed, which are three important aspects of integration onto semiconductors.

  6. Emerging memories: resistive switching mechanisms and current status

    NASA Astrophysics Data System (ADS)

    Jeong, Doo Seok; Thomas, Reji; Katiyar, R. S.; Scott, J. F.; Kohlstedt, H.; Petraru, A.; Hwang, Cheol Seong

    2012-07-01

    The resistance switching behaviour of several materials has recently attracted considerable attention for its application in non-volatile memory (NVM) devices, popularly described as resistive random access memories (RRAMs). RRAM is a type of NVM that uses a material(s) that changes the resistance when a voltage is applied. Resistive switching phenomena have been observed in many oxides: (i) binary transition metal oxides (TMOs), e.g. TiO2, Cr2O3, FeOx and NiO; (ii) perovskite-type complex TMOs that are variously functional, paraelectric, ferroelectric, multiferroic and magnetic, e.g. (Ba,Sr)TiO3, Pb(Zrx Ti1-x)O3, BiFeO3 and PrxCa1-xMnO3 (iii) large band gap high-k dielectrics, e.g. Al2O3 and Gd2O3; (iv) graphene oxides. In the non-oxide category, higher chalcogenides are front runners, e.g. In2Se3 and In2Te3. Hence, the number of materials showing this technologically interesting behaviour for information storage is enormous. Resistive switching in these materials can form the basis for the next generation of NVM, i.e. RRAM, when current semiconductor memory technology reaches its limit in terms of density. RRAMs may be the high-density and low-cost NVMs of the future. A review on this topic is of importance to focus concentration on the most promising materials to accelerate application into the semiconductor industry. This review is a small effort to realize the ambitious goal of RRAMs. Its basic focus is on resistive switching in various materials with particular emphasis on binary TMOs. It also addresses the current understanding of resistive switching behaviour. Moreover, a brief comparison between RRAMs and memristors is included. The review ends with the current status of RRAMs in terms of stability, scalability and switching speed, which are three important aspects of integration onto semiconductors.

  7. Effect of the eccentricity of normal resistivity borehole tools on the current field and resistivity measurement

    NASA Astrophysics Data System (ADS)

    Galsa, Attila; Herein, Mátyás; Drahos, Dezső; Herein, András

    2016-11-01

    Three-dimensional finite element numerical model calculations have been carried out to investigate the quantitative effect of the eccentric position of a normal resistivity borehole probe used in practice. Detailed calculations were done between the point-wise analytical solution and numerical solution to verify the results obtained from the finite element method for a normal probe with finite-length cylindrical electrodes. In the borehole the pattern of the current flowing out from current electrode A is efficiently influenced by the eccentricity. For high-resistivity rock the current density is decreased, while for low-resistivity rock it is increased toward the wall side. On the other hand, the eccentricity does not affect considerably the apparent resistivity calculated from electrode potentials. In most geological situations the deviation is less than 2%. However, in infrequent cases when the true resistivity of the rock is extremely low and/or the distance between the potential and current electrodes is very small the effect of the eccentricity can exceed even 10%.

  8. Fault current limiting characteristics of a new resistive type superconducting fault current limiter using flux linkage

    NASA Astrophysics Data System (ADS)

    Lim, Sung-Hun; Choi, Hyo-Sang; Ko, Seokcheol; Kang, Hyeong-Gon; Han, Byoung Sung

    2005-03-01

    The increase in capacities of power transmission and in fault currents of the related grid machinery has resulted in the development of various types of superconducting fault current limiters (SFCLs). One proposed solution to increase the voltage and current ratings of SFCL for application into real power system is the method to use the magnetically coupled coils or transformer. In this paper, we propose a new resistive type SFCL using flux linkage. The proposed SFCL consists of an YBCO thin film and a reactor, which is two coils wound in series on the same iron core. The operational characteristics were analyzed by using the equivalent circuit of the suggested SFCL and the fault current limiting characteristics were investigated through experiments. Through the analysis, it was shown that the limited fault current and the resistance of the high-TC superconducting (HTSC) element could be adjusted by ranging two coils' inductances and that this new resistive type SFCL could increase the short-circuit capacity of the SFCL.

  9. Criticality and turbulence in a resistive magnetohydrodynamic current sheet

    NASA Astrophysics Data System (ADS)

    Klimas, Alexander J.; Uritsky, Vadim M.

    2017-02-01

    Scaling properties of a two-dimensional (2d) plasma physical current-sheet simulation model involving a full set of magnetohydrodynamic (MHD) equations with current-dependent resistivity are investigated. The current sheet supports a spatial magnetic field reversal that is forced through loading of magnetic flux containing plasma at boundaries of the simulation domain. A balance is reached between loading and annihilation of the magnetic flux through reconnection at the current sheet; the transport of magnetic flux from boundaries to current sheet is realized in the form of spatiotemporal avalanches exhibiting power-law statistics of lifetimes and sizes. We identify this dynamics as self-organized criticality (SOC) by verifying an extended set of scaling laws related to both global and local properties of the current sheet (critical susceptibility, finite-size scaling of probability distributions, geometric exponents). The critical exponents obtained from this analysis suggest that the model operates in a slowly driven SOC state similar to the mean-field state of the directed stochastic sandpile model. We also investigate multiscale correlations in the velocity field and find them numerically indistinguishable from certain intermittent turbulence (IT) theories. The results provide clues on physical conditions for SOC behavior in a broad class of plasma systems with propagating instabilities, and suggest that SOC and IT may coexist in driven current sheets which occur ubiquitously in astrophysical and space plasmas.

  10. Criticality and turbulence in a resistive magnetohydrodynamic current sheet.

    PubMed

    Klimas, Alexander J; Uritsky, Vadim M

    2017-02-01

    Scaling properties of a two-dimensional (2d) plasma physical current-sheet simulation model involving a full set of magnetohydrodynamic (MHD) equations with current-dependent resistivity are investigated. The current sheet supports a spatial magnetic field reversal that is forced through loading of magnetic flux containing plasma at boundaries of the simulation domain. A balance is reached between loading and annihilation of the magnetic flux through reconnection at the current sheet; the transport of magnetic flux from boundaries to current sheet is realized in the form of spatiotemporal avalanches exhibiting power-law statistics of lifetimes and sizes. We identify this dynamics as self-organized criticality (SOC) by verifying an extended set of scaling laws related to both global and local properties of the current sheet (critical susceptibility, finite-size scaling of probability distributions, geometric exponents). The critical exponents obtained from this analysis suggest that the model operates in a slowly driven SOC state similar to the mean-field state of the directed stochastic sandpile model. We also investigate multiscale correlations in the velocity field and find them numerically indistinguishable from certain intermittent turbulence (IT) theories. The results provide clues on physical conditions for SOC behavior in a broad class of plasma systems with propagating instabilities, and suggest that SOC and IT may coexist in driven current sheets which occur ubiquitously in astrophysical and space plasmas.

  11. Nanomedicinal strategies to treat multidrug-resistant tumors: current progress

    PubMed Central

    Dong, Xiaowei; Mumper, Russell J

    2010-01-01

    Multidrug resistance (MDR) is a major impediment to the success of cancer chemotherapy. P-glycoprotein is an important and the best-known membrane transporter involved in MDR. Several strategies have been used to address MDR, especially P-glycoprotein-mediated drug resistance in tumors. However, clinical success has been limited, largely due to issues regarding lack of efficacy and/or safety. Nanoparticles have shown the ability to target tumors based on their unique physical and biological properties. To date, nanoparticles have been investigated primarily to address P-glycoprotein and the observed improved anticancer efficacy suggests that nanomedicinal strategies provide a new opportunity to overcome MDR. This article focuses on nanotechnology-based formulations and current nanomedicine approaches to address MDR in tumors and discusses the proposed mechanisms of action. PMID:20528455

  12. An evaluation of candidate oxidation resistant materials

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon; Banks, Bruce; Mirtich, Michael; Difilippo, Frank; Hotes, Deborah; Labed, Richard; Dever, Terese; Kussmaul, Michael

    1987-01-01

    Ground based testing of materials considered for Kapton solar array blanket protection, graphite epoxy structural member protection, and high temperature radiators was performed in an RF plasma asher. Ashing rates for Kapton were correlated with rates measured on STS-8 to determine the exposure time equivalent to one year in low Earth orbit (LEO) at a constant density space station orbital flux. Protective coatings on Kapton from Tekmat, Andus Corporation, and LeRC were evaluated in the plasma asher and mass loss rates per unit area were measured for each sample. All samples evaluated provided some protection to the underlying surface but ion beam sputter deposited samples of SiO2 and SiO2 with 8% polytetrafluoroethylene (PTFE) showed no evidence of degradation after 47 hours of exposure. Mica paint was evaluated as a protective coating for graphite epoxy structural members. Mica appears to be resistant to attack by atomic oxygen but only offers some limited protection as a paint because the paint vehicles evaluated to date were not resistant to atomic oxygen. Four materials were selected for evaluation as candidate radiator materials: stainless steel, copper, niobium-1% zirconium, and titanium-6% aluminum-4% vanadium. These materials were surface textured by various means to improve their emittance. Emittances as high as 0.93 at 2.5 microns for stainless steel and 0.89 at 2.5 microns for Nb-1 Zr were obtained from surface texturing. There were no significant changes in emittance after asher exposure.

  13. Protein detection using tunable pores: resistive pulses and current rectification.

    PubMed

    Blundell, Emma L C J; Mayne, Laura J; Lickorish, Michael; Christie, Steven D R; Platt, Mark

    2016-12-12

    We present the first comparison between assays that use resistive pulses or rectification ratios on a tunable pore platform. We compare their ability to quantify the cancer biomarker Vascular Endothelial Growth Factor (VEGF). The first assay measures the electrophoretic mobility of aptamer modified nanoparticles as they traverse the pore. By controlling the aptamer loading on the particle surface, and measuring the speed of each translocation event we are able to observe a change in velocity as low as 18 pM. A second non-particle assay exploits the current rectification properties of conical pores. We report the first use of Layer-by-Layer (LbL) assembly of polyelectrolytes onto the surface of the polyurethane pore. The current rectification ratios demonstrate the presence of the polymers, producing pH and ionic strength-dependent currents. The LbL assembly allows the facile immobilisation of DNA aptamers onto the pore allowing a specific dose response to VEGF. Monitoring changes to the current rectification allows for a rapid detection of 5 pM VEGF. Each assay format offers advantages in their setup and ease of preparation but comparable sensitivities.

  14. Multidrug-resistant and extensively drug-resistant Gram-negative pathogens: current and emerging therapeutic approaches

    PubMed Central

    Karaiskos, Ilias; Giamarellou, Helen

    2014-01-01

    Introduction: In the era of multidrug-resistant, extensively drug-resistant (XDR) and even pandrug-resistant Gram-negative microorganisms, the medical community is facing the threat of untreatable infections particularly those caused by carbapenemase-producing bacteria, that is, Klebsiella pneumoniae, Pseudomonas aeruginosa and Acinetobacter baumannii. Therefore, all the presently available antibiotics, as well as for the near future compounds, are presented and discussed. Areas covered: Current knowledge concerning mechanisms of action, in vitro activity and interactions, pharmacokinetic/pharmacodynamics, clinical efficacy and toxicity issues for revived and novel antimicrobial agents overcoming current resistance mechanisms, including colistin, tigecycline, fosfomycin, temocillin, carbapenems, and antibiotics still under development for the near future such as plazomicin, eravacycline and carbapenemase inhibitors is discussed. Expert opinion: Colistin is active in vitro and effective in vivo against XDR carbapenemase-producing microorganisms in the critically ill host, whereas tigecycline, with the exception of P. aeruginosa, has a similar spectrum of activity. The efficacy of combination therapy in bacteremias and ventilator-associated pneumonia caused by K. pneumoniae carbapenemase producers seems to be obligatory, whereas in cases of P. aeruginosa and A. baumannii its efficacy is questionable. Fosfomycin, which is active against P. aeruginosa and K. pneumoniae, although promising, shares poor experience in XDR infections. The in vivo validity of the newer potent compounds still necessitates the evaluation of Phase III clinical trials particularly in XDR infections. PMID:24766095

  15. Data fusion analysis of a surface direct-current resistivity and well pick data set

    SciTech Connect

    Clayton, E.A.; Lewis, R.E.

    1995-09-01

    Pacific Northwest Laboratory (PNL) has been tasked with testing, debugging, and refining the Hanford Site data fusion workstation (DFW), with the assistance of Coleman Research Corporation (CRC), before delivering the DFW to the environmental restoration client at the Hanford Site. Data fusion is the mathematical combination (or fusion) of disparate data sets into a single interpretation. The data fusion software used in this study was developed by CRC. This report discusses the results of evaluating a surface direct-current (dc) resistivity and well-pick data set using two methods: data fusion technology and commercially available software (i.e., RESIX Plus from Interpex Ltd., Golden, Colorado), the conventional method of analysis. The report compares the two technologies; describes the survey, procedures, and results; and includes conclusions and recommendations. The surface dc resistivity and well-pick data set had been acquired by PNL from a study performed in May 1993 at Eielson Air Force Base near Fairbanks, Alaska. The resistivity survey data were acquired to map the top of permafrost in support of a hydrogeologic study. This data set provided an excellent opportunity to test and refine the dc resistivity capabilities of the DFW; previously, the data fusion software was untested on dc resistivity data. The DFW was used to evaluate the dc resistivity survey data and to produce a 3-dimensional earth model of the study area.

  16. Module Five: Relationships of Current, Voltage, and Resistance; Basic Electricity and Electronics Individualized Learning System.

    ERIC Educational Resources Information Center

    Bureau of Naval Personnel, Washington, DC.

    This module covers the relationships between current and voltage; resistance in a series circuit; how to determine the values of current, voltage, resistance, and power in resistive series circuits; the effects of source internal resistance; and an introduction to the troubleshooting of series circuits. This module is divided into five lessons:…

  17. Evaluation of Ferrite Chip Beads as Surge Current Limiters in Circuits with Tantalum Capacitors

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander

    2014-01-01

    Limiting resistors are currently required to be connected in series with tantalum capacitors to reduce the risk of surge current failures. However, application of limiting resistors decreases substantially the efficiency of the power supply systems. An ideal surge current limiting device should have a negligible resistance for DC currents and high resistance at frequencies corresponding to transients in tantalum capacitors. This work evaluates the possibility of using chip ferrite beads (FB) as such devices. Twelve types of small size FBs from three manufacturers were used to evaluate their robustness under soldering stresses and at high surge current spikes associated with transients in tantalum capacitors. Results show that FBs are capable to withstand current pulses that are substantially greater than the specified current limits. However, due to a sharp decrease of impedance with current, FBs do not reduce surge currents to the required level that can be achieved with regular resistors.

  18. An automated cryogenic current comparator resistance ratio bridge for routine resistance measurements

    NASA Astrophysics Data System (ADS)

    Williams, J. M.; Janssen, T. J. B. M.; Rietveld, G.; Houtzager, E.

    2010-06-01

    A design of an automated cryogenic current comparator (CCC) resistance ratio bridge for routine measurements in a national metrology institute or standards laboratory is described. It employs a type II CCC for use in a low loss liquid helium storage vessel and can be continuously operated from the mains power via specialized isolated supplies. All parameters including the servo control loops are digitally controlled. Noise sources in the system are analysed using the Allan deviation and it is demonstrated that non-white noise sources can be eliminated by choosing an appropriate current reversal rate.

  19. [Current resistence situation in a surgical and urological department].

    PubMed

    Wacha, H; Stix, H

    1976-04-15

    Spectrum and sensitivity of bacteria were studied at the Surgical (534 positive wound smears) and the Urological Clinics (7879 urine specimens). Krankenhaus Nordwest, Frankfurt/M., during the period of 1969-1971 and in 1973. The most common organisms identified in wound smears were E. coli, followed by Staph. areus, Aerobacter and Proteus species. E. coli were also predominant in urine, but followed by Enterococci, Proteus and Pseudomonas. E. coli, Proteus species and especially Pseudomonas increased in number whereas Enterococci decreased. There was no pronounced increase in resistance to 9 current antibiotics as well as to chemotherapeutics during the observation period which was particularly striking in the case of Ampicillin used on a large scale. The results of our study support the presently employed therapeutic method using bactericidal antibiotics of the penicillin group in strict indications.

  20. Confirmation of resistance to herbicides and evaluation of resistance levels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As cases of resistance to herbicides escalate worldwide, there is increasing demand from growers to test for weed resistance and how to manage it. Scientists have developed resistance testing protocols for numerous herbicides and weed species. Growers need immediate answers and scientists are faced ...

  1. Direct-current resistivity data from 94 sites in northeastern Palm Beach County, Florida

    USGS Publications Warehouse

    Peterson, Cathleen J.

    1988-01-01

    Direct-current resistivity data were collected from 94 vertical electric sounding profiles in northeastern Palm Beach County, Florida. Direct-current resistivity data, which may be used to determine the location and thicknesses of shallow, semipermeable marls or locate zones of high chloride concentration, are presented in this report. The resistivity data consist of field data, smoothed data, layer resistivity from smoothed data, and Cartesian graphs of resistivity in relation to depth for 94 sites located in northeastern Palm Beach County. (USGS)

  2. [Current approaches to overcoming permethrin resistance in lice].

    PubMed

    Lopatina, Iu V

    2013-01-01

    The paper gives information on pediculosis morbidity worldwide. It summarizes the data available in the literature on the resistance of head and clothes lice to pyrethroids and on the mechanisms of this resistance. The formation of head and clothes louse populations resistant to pyrethroids is shown to be a global problem. New groups of chemical substances that are alternatives to pyrethroids and the mechanisms of their action on lice are considered.

  3. Current and novel antibiotics against resistant Gram-positive bacteria

    PubMed Central

    Perez, Federico; Salata, Robert A; Bonomo, Robert A

    2008-01-01

    The challenge posed by resistance among Gram-positive bacteria, epitomized by methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant Enterococcus (VRE) and vancomycin-intermediate and -resistant S. aureus (VISA and VRSA) is being met by a new generation of antimicrobials. This review focuses on the new β-lactams with activity against MRSA (ceftobiprole and ceftaroline) and on the new glycopeptides (oritavancin, dalbavancin, and telavancin). It will also consider the role of vancomycin in an era of existing alternatives such as linezolid, daptomycin and tigecycline. Finally, compounds in early development are described, such as iclaprim, friulimicin, and retapamulin, among others. PMID:21694878

  4. Taguchi Optimization of Pulsed Current GTA Welding Parameters for Improved Corrosion Resistance of 5083 Aluminum Welds

    NASA Astrophysics Data System (ADS)

    Rastkerdar, E.; Shamanian, M.; Saatchi, A.

    2013-04-01

    In this study, the Taguchi method was used as a design of experiment (DOE) technique to optimize the pulsed current gas tungsten arc welding (GTAW) parameters for improved pitting corrosion resistance of AA5083-H18 aluminum alloy welds. A L9 (34) orthogonal array of the Taguchi design was used, which involves nine experiments for four parameters: peak current ( P), base current ( B), percent pulse-on time ( T), and pulse frequency ( F) with three levels was used. Pitting corrosion resistance in 3.5 wt.% NaCl solution was evaluated by anodic polarization tests at room temperature and calculating the width of the passive region (∆ E pit). Analysis of variance (ANOVA) was performed on the measured data and S/ N (signal to noise) ratios. The "bigger is better" was selected as the quality characteristic (QC). The optimum conditions were found as 170 A, 85 A, 40%, and 6 Hz for P, B, T, and F factors, respectively. The study showed that the percent pulse-on time has the highest influence on the pitting corrosion resistance (50.48%) followed by pulse frequency (28.62%), peak current (11.05%) and base current (9.86%). The range of optimum ∆ E pit at optimum conditions with a confidence level of 90% was predicted to be between 174.81 and 177.74 mVSCE. Under optimum conditions, the confirmation test was carried out, and the experimental value of ∆ E pit of 176 mVSCE was in agreement with the predicted value from the Taguchi model. In this regard, the model can be effectively used to predict the ∆ E pit of pulsed current gas tungsten arc welded joints.

  5. Assessment on the influence of resistive superconducting fault current limiter in VSC-HVDC system

    NASA Astrophysics Data System (ADS)

    Lee, Jong-Geon; Khan, Umer Amir; Hwang, Jae-Sang; Seong, Jae-Kyu; Shin, Woo-Ju; Park, Byung-Bae; Lee, Bang-Wook

    2014-09-01

    Due to fewer risk of commutation failures, harmonic occurrences and reactive power consumptions, Voltage Source Converter (VSC) based HVDC system is known as the optimum solution of HVDC power system for the future power grid. However, the absence of suitable fault protection devices for HVDC system hinders the efficient VSC-HVDC power grid design. In order to enhance the reliability of the VSC-HVDC power grid against the fault current problems, the application of resistive Superconducting Fault Current Limiters (SFCLs) could be considered. Also, SFCLs could be applied to the VSC-HVDC system with integrated AC Power Systems in order to enhance the transient response and the robustness of the system. In this paper, in order to evaluate the role of SFCLs in VSC-HVDC systems and to determine the suitable position of SFCLs in VSC-HVDC power systems integrated with AC power System, a simulation model based on Korea Jeju-Haenam HVDC power system was designed in Matlab Simulink/SimPowerSystems. This designed model was composed of VSC-HVDC system connected with an AC microgrid. Utilizing the designed VSC-HVDC systems, the feasible locations of resistive SFCLs were evaluated when DC line-to-line, DC line-to-ground and three phase AC faults were occurred. Consequently, it was found that the simulation model was effective to evaluate the positive effects of resistive SFCLs for the effective suppression of fault currents in VSC-HVDC systems as well as in integrated AC Systems. Finally, the optimum locations of SFCLs in VSC-HVDC transmission systems were suggested based on the simulation results.

  6. Damage Resistance of Titanium Aluminide Evaluated

    NASA Technical Reports Server (NTRS)

    Lerch, Bradley A.; Draper, Susan L.; Baaklini, George Y.; Pereira, J. Michael; Austin, Curt

    2000-01-01

    As part of the aviation safety goal to reduce the aircraft accident rate, NASA has undertaken studies to develop durable engine component materials. One of these materials, g-TiAl, has superior high-temperature material properties. Its low density provides improved specific strength and creep resistance in comparison to currently used titanium alloys. However, this intermetallic is inherently brittle, and long life durability is a potential problem. Of particular concern is the material s sensitivity to defects, which may form during the manufacturing process or in service. To determine the sensitivity of TiAl to defects, a team consisting of GE Aircraft Engines, Precision Cast Parts, and NASA was formed. The work at the NASA Glenn Research Center at Lewis Field has concentrated on the fatigue response to specimens containing defects. The overall objective of this work is to determine the influence of defects on the high cycle fatigue life of TiAl-simulated low-pressure turbine blades. Two types of defects have been introduced into the specimens: cracking from impact damage and casting porosity. For both types of defects, the cast-to-size fatigue specimens were fatigue tested at 650 C and 100 Hz until failure.

  7. CURRENT ISSUES REGARDING ENDOCRINE DISRUPTING CHEMICALS AND ANTIBIOTIC RESISTANCE

    EPA Science Inventory

    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...

  8. Current perspectivesin pathogenesis and antimicrobial resistance of enteroaggregative Escherichia coli.

    PubMed

    Kong, Haishen; Hong, Xiaoping; Li, Xuefen

    2015-08-01

    Enteroaggregative Escherichia coli (EAEC) is an emerging pathogen that causes acute and persistent diarrhea in children and adults. While the pathogenic mechanisms of EAEC intestinal colonization have been uncovered (including bacterial adhesion, enterotoxin and cytotoxin secretion, and stimulation of mucosal inflammation), those of severe extraintestinal infections remain largely unknown. The recent emergence of multidrug resistant EAEC represents an alarming public health threat and clinical challenge, and research on the molecular mechanisms of resistance is urgently needed.

  9. Schilling evaluation of pernicious anemia: current status

    SciTech Connect

    Zuckier, L.S.; Chervu, L.R.

    1984-09-01

    The Schilling examination remains a popular means of evaluating in vivo absorption of vitamin B/sub 12/. When absorption is abnormally low, the test may be repeated with addition to exogenous intrinsic factor (IF) in order to correct the IF deficiency that characterizes pernicious anemia. A dual-isotope variation provides a means of performing both stages of the test simultaneously, thereby speeding up the test and reducing dependence on complete urine collection. In vivo studies indicate that, when administered simultaneously, the absorption of unbound B/sub 12/ is elevated, and IF-bound B/sub 12/ is reduced, in pernicious-anemia patients, relative to the classic two-stage examination. A number of clinical studies indicate significant difficulty in resolving clincial diagnoses with the dual-tracer test. An algorithm is offered for selecting the most suitable variation of the Schilling test to improve the accuracy of test results and the ease of performance.

  10. Multidrug resistant Enterobacteriaceae in New Zealand: a current perspective.

    PubMed

    Toombs-Ruane, L J; Benschop, J; Burgess, S; Priest, P; Murdoch, D R; French, N P

    2017-03-01

    In this article we review mechanisms and potential transmission pathways of multidrug resistance in Enterobacteriaceae, with an emphasis on extended-spectrum β-lactamase (ESBL)-production. This provides background to better understand challenges presented by this important group of antimicrobial resistant bacteria, and inform measures aimed at prevention and control of antimicrobial resistance in general. Humans and animals interact at various levels; household pets cohabit with humans, and other animals interact with people through direct contact, as well as through the food chain and the environment. These interactions offer opportunity for bacteria such as ESBL-producers to be shared and transmitted between species and, in turn, increase the risk of zoonotic and reverse-zoonotic disease transmission. A key step in curtailing antimicrobial resistance is improved stewardship of antimicrobials, including surveillance of their use, better infection-control and prevention, and a better understanding of prescribing practice in both veterinary and medical professions in New Zealand. This will also require prospective observational studies to examine risk factors for antimicrobial resistance. Due to the interconnectedness of humans, animals and the environment actions to effect the changes required should be undertaken using a One Health approach.

  11. Field evaluation of rice varieties for resistance to major diseases

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The development and use of improved disease resistant rice varieties remains of foremost importance to rice producers, with field evaluation under local environments essential. In this study, we evaluated new and existing varieties, potential releases, and Texas elite breeding lines for resistance t...

  12. 40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress resistance... Procedures § 91.427 Catalyst thermal stress resistance evaluation. (a)(1) The purpose of the evaluation procedure specified in this section is to determine the effect of thermal stress on catalyst...

  13. 40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Catalyst thermal stress resistance... Procedures § 91.427 Catalyst thermal stress resistance evaluation. (a)(1) The purpose of the evaluation procedure specified in this section is to determine the effect of thermal stress on catalyst...

  14. 40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Catalyst thermal stress resistance... Procedures § 91.427 Catalyst thermal stress resistance evaluation. (a)(1) The purpose of the evaluation procedure specified in this section is to determine the effect of thermal stress on catalyst...

  15. 40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Catalyst thermal stress resistance... Procedures § 91.427 Catalyst thermal stress resistance evaluation. (a)(1) The purpose of the evaluation procedure specified in this section is to determine the effect of thermal stress on catalyst...

  16. 40 CFR 91.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Catalyst thermal stress resistance... Procedures § 91.427 Catalyst thermal stress resistance evaluation. (a)(1) The purpose of the evaluation procedure specified in this section is to determine the effect of thermal stress on catalyst...

  17. Evaluation of industrial platinum resistance thermometers

    NASA Technical Reports Server (NTRS)

    Daryabeigi, Kamran; Dillontownes, Lawrence A.; Alderfer, David W.

    1987-01-01

    The calibration and stability of four surface temperature measuring industrial platinum resistance thermometers for use in the temperature range -120 C to 160 C was investigated. It was found that the calibration formulation of the International Practical Temperature Scale of 1968 provided the most accurate calibration. It was also found that all the resistance thermometers suffered from varying degrees of instability and hysteresis.

  18. The constant current loop - A new paradigm for resistance signal conditioning

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1993-01-01

    A practical single constant current loop circuit for the signal conditioning of variable-resistance transducers has been synthesized, analyzed, and demonstrated. The strain gage and the resistance temperature device are examples of variable-resistance sensors. Lead wires connect variable-resistance sensors to remotely located signal-conditioning hardware. The presence of lead wires in the conventional Wheatstone bridge signal-conditioning circuit introduces undesired effects that reduce the quality of the data from the remote sensors. A practical approach is presented for suppressing essentially all lead wire resistance effects while indicating only the change in resistance value. An adaptation of the current loop circuit is presented that simultaneously provides an output signal voltage directly proportional to transducer resistance change and provides temperature information that is unaffected by transducer and lead wire resistance variations.

  19. Current advances on genetic resistance to rice blast disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rice blast disease caused by the fungal pathogen Magnaporthe oryzae is one of the most threatening fungal diseases resulting in significant annual crop losses worldwide. Blast disease has been effectively managed by a combination of resistant (R) gene deployment, application of fungicides, and suita...

  20. Direct current resistivity profiling to study distribution of water in the unsaturated zone near the Amargosa Desert Research Site, Nevada

    USGS Publications Warehouse

    Abraham, Jared D.; Lucius, Jeffrey E.

    2004-01-01

    In order to study the distribution of water in the unsaturated zone and potential for ground-water recharge near the Amargosa Desert Research Site south of Beatty, Nevada, the U.S. Geological Survey collected direct-current resistivity measurements along three profiles in May 2003 using an eight-channel resistivity imaging system. Resistivity data were collected along profiles across the ADRS, across a poorly incised (distributary) channel system of the Amargosa River southwest of the ADRS, and across a well-incised flood plain of the Amargosa River northwest of the ADRS. This report describes results of an initial investigation to estimate the distribution of water in the unsaturated zone and to evaluate the shallow subsurface stratigraphy near the ADRS. The geophysical method of dc resistivity was employed by using automated data collection with numerous electrodes. 'Cross sections' of resistivity, produced by using an inversion algorithm on the field data, at the three field sites are presented and interpreted.

  1. Resistance of 4H-SiC Schottky barriers at high forward-current densities

    SciTech Connect

    Ivanov, P. A. Samsonova, T. P.; Il’inskaya, N. D.; Serebrennikova, O. Yu.; Kon’kov, O. I.; Potapov, A. S.

    2015-07-15

    The resistance of Schottky barriers based on 4H-SiC is experimentally determined at high forward-current densities. The measured resistance is found to be significantly higher than the resistance predicted by classical mechanisms of electron transport in Schottky contacts. An assumption concerning the crucial contribution of the tunnel-transparent intermediate oxide layer between the metal and semiconductor to the barrier resistance is proposed and partially justified.

  2. Evaluation of pea accessions and commercial cultivars for Fusarium Root Rot resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium root rot caused by Fusarium solani f. sp. pisi (Fsp) can result in major yield losses in pea (Pisum sativum L.). Currently no fungicides effectively manage this disease. Previous studies evaluated the Pisum germplasm collection for resistance to Fsp, however, evaluations of commercial marke...

  3. The slippery difficulty of ever containing drug resistance with current practices.

    PubMed

    Fullybright, R

    2017-04-01

    It has previously been shown that the rate of drug resistance emergence in medicine is exponential, while we have been producing drugs at a much lower rate. Our ability to successfully contain resistance at any one time is function of how many drugs we have at our disposal to counter new resistances from pathogens. Here, we assess our level of preparedness through a mathematical comparison of the drug manufacture rate by the pharmaceutical industry with the resistance emergence rate in pathogens. To that effect, changes in the rates of growth of the drugs production and resistance emergence processes are computed over multiple time segments and compared. It is found that new resistance emergence rate in infectious diseases medicine remains mathematically and permanently ahead of the drugs production rate by the pharmaceutical industry. Consequently, we are not in a position to ever contain current or future strengths of resistance from pathogens. A review of current practices is called for.

  4. A National Perspective on the Current Evaluation Activities in Extension

    ERIC Educational Resources Information Center

    Lamm, Alexa J.; Israel, Glenn D.; Diehl, David

    2013-01-01

    In order to enhance Extension evaluation efforts it is important to understand current practices. The study reported here researched the evaluation behaviors of county-based Extension professionals. Extension professionals from eight states (n = 1,173) responded to a survey regarding their evaluation data collection, analysis, and reporting…

  5. Visco-resistive tearing in thin current sheets.

    NASA Astrophysics Data System (ADS)

    Velli, M. M. C.; Tenerani, A.; Rappazzo, A. F.; Pucci, F.

    2014-12-01

    How fast magnetic energy release is triggered and occurs in high Lundquist (S) and high Reynolds number ( R ) plasmas such as that of the solar corona is a fundamental problem for understanding phenomena ranging from coronal heating to flares and CMEs. Diffusion or collisional reconnection driven by macroscopic flows in quasi-steady Sweet-Parker (SP) current sheets are processes far too slow to fit observational data. Spontaneous reconnection, driven by the onset of the tearing instability inside current sheets, provides an alternative paradigm to SP reconnection. Nevertheless, as long as macroscopic current layers are considered, the growth of such an instability is also a slow process. Recently it has been shown that SP current sheets are rapidly unstable in high S plasmas, indeed have a growth rate diverging with increasing S. It has been suggested that such instabilities are triggered during the nonlinear stage of the primary tearing instability of a macroscopic layer. The formation of plasmoids in this presumed SP sheet speeds up the reconnection rate to ideal values. Recently, we have suggested that SP sheets can not be realized in quasi-ideal plasmas, and that the plasmoid instability is triggered on a much larger scale (i.e. with current sheets having a much larger ration of thickness to length than SP). Here we present a linear parametric study of the tearing instability for a Harris current sheet, while taking into account both viscosity and current sheets of variable aspect ratios. The present study shows that an explosive growth of the reconnection rate may be reached during the linear stage, once a critical width of the current layer is reached. In the absence of a strong guide field this depends on viscosity and a range of critical aspect ratios can be found for different values of S, R, or S and Prandtl number.

  6. [Multidrug-resistant tuberculosis: current epidemiology, therapeutic regimens, new drugs].

    PubMed

    Gómez-Ayerbe, C; Vivancos, M J; Moreno, S

    2016-09-01

    Multidrug and extensively resistant tuberculosis are especially severe forms of the disease for which no efficacious therapy exists in many cases. All the countries in the world have registered cases, although most of them are diagnosed in resource-limited countries from Asia, Africa and South America. For adequate treatment, first- and second-line antituberculosis drugs have to be judiciously used, but the development of new drugs with full activity, good tolerability and little toxicity is urgently needed. There are some drugs in development, some of which are already available through expanded-access programs.

  7. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 21 2013-07-01 2013-07-01 false Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst...

  8. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 20 2014-07-01 2013-07-01 true Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst...

  9. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 20 2010-07-01 2010-07-01 false Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst...

  10. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 20 2011-07-01 2011-07-01 false Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst...

  11. 40 CFR 90.427 - Catalyst thermal stress resistance evaluation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 21 2012-07-01 2012-07-01 false Catalyst thermal stress resistance... Gaseous Exhaust Test Procedures § 90.427 Catalyst thermal stress resistance evaluation. (a) The purpose of... catalyst conversion efficiency for Phase 1 engines. The thermal stress is imposed on the test catalyst...

  12. The constant current loop: A new paradigm for resistance signal conditioning

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1994-01-01

    A practical single constant current loop circuit for the signal conditioning of variable-resistance transducers has been synthesized, analyzed, and demonstrated. The strain gage and the resistance temperature detector are examples of variable-resistance sensors. Lead wires connect variable-resistance sensors to remotely located signal-conditioning hardware. The presence of lead wires in the conventional Wheatstone bridge signal-conditioning circuit introduces undesired effects that reduce the quality of the data from the remote sensors. A practical approach is presented for suppressing essentially all lead wire resistance effects while indicating only the change in resistance value. Theoretical predictions supported by laboratory testing confirm the following features of the approach: (1) dc response; (2) the electrical output is unaffected by extremely large variation in the resistance of any or all lead wires; (3) the electrical output remains zero for no change in gage resistance; (4) the electrical output is inherently linear with respect to gage resistance change; (5) the sensitivity is double that of a Wheatstone bridge circuit; and (6) the same excitation wires can serve multiple independent gages. An adaptation of current loop circuit is presented that simultaneously provides an output signal voltage directly proportional to transducer resistance change and provides temperature information that is unaffected by transducer and lead wire resistance variations. These innovations are the subject of NASA patent applications.

  13. The constant current loop: A new paradigm for resistance signal conditioning

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1992-01-01

    A practical single constant current loop circuit for the signal conditioning of variable resistance transducers has been synthesized, analyzed, and demonstrated. The strain gage and the resistance temperature device are examples of variable resistance sensors. Lead wires connect variable resistance sensors to remotely located signal conditioning hardware. The presence of lead wires in the conventional Wheatstone bridge signal conditioning circuit introduces undesired effects that reduce the quality of the data from the remote sensors. A practical approach is presented for suppressing essentially all lead wire resistance effects while indicating only the change in resistance value. Theoretical predictions supported by laboratory testing confirm the following features of the approach: (1) dc response; (2) the electrical output is unaffected by extremely large variations in the resistance of any or all lead wires; (3) the electrical output remains zero for no change in gage resistance; (4) the electrical output is inherently linear with respect to gage resistance change; (5) the sensitivity is double that of a Wheatstone bridge circuit; and (6) the same excitation wires can serve multiple independent gages. An adaptation of current loop circuit is presented that simultaneously provides an output signal voltage directly proportional to transducer resistance change and provides temperature information that is unaffected by transducer and lead wire resistance variations. These innovations are the subject of NASA patent applications.

  14. The constant current loop: A new paradigm for resistance signal conditioning

    NASA Technical Reports Server (NTRS)

    Anderson, Karl F.

    1993-01-01

    A practical, single, constant-current loop circuit for the signal conditioning of variable-resistance transducers was synthesized, analyzed, and demonstrated. The strain gage and the resistance temperature device are examples of variable-resistance sensors. Lead wires connect variable-resistance sensors to remotely located signal-conditioning hardware. The presence of lead wires in the conventional Wheatstone bridge signal-conditioning circuit introduces undesired effects that reduce the quality of the data from the remote sensors. A practical approach is presented for suppressing essentially all lead wire resistance effects while indicating only the change in resistance value. Theoretical predictions supported by laboratory testing confirm the following features of the approach: (1) the dc response; (2) the electrical output is unaffected by extremely large variations in the resistance of any or all lead wires; (3) the electrical output remains zero for no change in gage resistance; (4) the electrical output is inherently linear with respect to gage resistance change; (5) the sensitivity is double that of a Wheatstone bridge circuit; and (6) the same excitation and sense wires can serve multiple independent gages. An adaptation of the current loop circuit is presented that simultaneously provides an output signal voltage directly proportional to transducer resistance change and provides temperature information that is unaffected by transducer and lead wire resistance variations. These innovations are the subject of NASA patent applications.

  15. Stochastic macromodel of magnetic tunnel junction resistance variation and critical current dependence on resistance variation for SPICE simulation

    NASA Astrophysics Data System (ADS)

    Choi, Juntae; Song, Yunheub

    2017-04-01

    The resistance distribution of a magnetic tunnel junction (MTJ) shows nonuniformity according to various MTJ parameters. Moreover, this resistance variation leads to write-current density variation, which can cause serious problems when designing peripheral circuits for spin transfer torque magnetoresistance random access memory (STT-MRAM) and commercializing gigabit STT-MRAM. Therefore, a macromodel of MTJ including resistance, tunneling magnetoresistance ratio (TMR), and critical current variations is required for circuit designers to design MRAM peripheral circuits, that can overcome the various effects of the variations, such as write failure and read failure, and realize STT-MRAM. In this study, we investigated a stochastic behavior macromodel of the write current dependence on the MTJ resistance variation. The proposed model can possibly be used to analyze the write current density in relation to the resistance and TMR variations of MTJ with various parameter variations. It can be very helpful for designing STT-MRAM circuits and simulating the operation of STT-MRAM devices considering MTJ variations.

  16. Evaluation of pozzolanic activity by the electric resistance measurement method

    SciTech Connect

    Tashiro, Chuichi; Ikeda, Ko . Dept. of Advanced Materials Science and Engineering); Inoue, Yoshihiro )

    1994-01-01

    Measurements of electric resistance and amount of consumption of portlandite were carried out in accelerated curing conditions by preparing pastes of Fine Ceraments, fly ash, silica fume, kaolin, acid clay, zeolite and quartz activated with portlandite. Electric resistances of reactive pozzolans showed sharp rises except that of kaolin, whereas that of inactive material, quartz, showed no sharp rise. Electric resistances are proportional to the consumptions of portlandite except for fly ashes. The electric resistance measurement method combined with portlandite consumption measurement is useful to the rapid evaluation of pozzolanic activity.

  17. Wear Resistance of Friction Pair of Metal Composite/Copper under Electric Current

    NASA Astrophysics Data System (ADS)

    Aleutdinova, M. I.; Fadin, V. V.; Rubtsov, V. Ye; Aleutdinov, K. A.

    2016-11-01

    Sliding of metal composites against copper counterbody under severe conditions (i.e. at the contact current density higher 50 A/cm2 and at high roughness of counterbody) is carried out. It is shown that the composite of composition of Cu-30% of graphite shows low wear resistance in these conditions. Higher wear resistance is inherent in the composites containing lead and bearing steel. Impregnation of these composites by industrial oil hasn't led to noticeable increase in wear resistance.

  18. Evaluating Teaching: A Guide to Current Thinking and Best Practice.

    ERIC Educational Resources Information Center

    Stronge, James, Ed.

    This guide presents current research and thinking about teacher evaluation and combines that research with practice. Chapters contain illustrations and examples to make a research-practice connection and present a comprehensive approach to designing, implementing, and monitoring quality teacher-evaluation systems. Chapters include: (1) "Improving…

  19. A Limited In-Flight Evaluation of the Constant Current Loop Strain Measurement Method

    NASA Technical Reports Server (NTRS)

    Olney, Candida D.; Collura, Joseph V.

    1997-01-01

    For many years, the Wheatstone bridge has been used successfully to measure electrical resistance and changes in that resistance. However, the inherent problem of varying lead wire resistance can cause errors when the Wheatstone bridge is used to measure strain in a flight environment. The constant current loop signal-conditioning card was developed to overcome that difficulty. This paper describes a limited evaluation of the constant current loop strain measurement method as used in the F-16XL ship 2 Supersonic Laminar Flow Control flight project. Several identical strain gages were installed in close proximity on a shock fence which was mounted under the left wing of the F- 1 6XL ship 2. Two strain gage bridges were configured using the constant current loop, and two were configured using the Wheatstone bridge circuitry. Flight data comparing the output from the constant current loop configured gages to that of the Wheatstone bridges with respect to signal output, error, and noise are given. Results indicate that the constant current loop strain measurement method enables an increased output, unaffected by lead wire resistance variations, to be obtained from strain gages.

  20. Evaluation of minocycline susceptibility of methicillin-resistant Staphylococcus pseudintermedius.

    PubMed

    Weese, J S; Sweetman, K; Edson, H; Rousseau, J

    2013-03-23

    Methicillin-resistant Staphylococcus pseudintermedius (MRSP) is an increasingly important cause of opportunistic infections in dogs and cats. Treatment options are often limited because of the high level of antimicrobial resistance. Doxycycline resistance is common, but variable mechanisms of doxycycline resistance exist, with some conferring resistance to doxycycline but not minocycline. However, there has been limited study of minocycline susceptibility in clinical MRSP isolates nor has the association of susceptibility and clonal complex been clearly established. The objective of this study was to evaluate the susceptibility of MRSP to tetracycline, doxycycline and minocycline, to determine the prevalence of tet(M) and tet(K) and to evaluate the impact of strain on minocycline susceptibility. One hundred seven MRSP isolates from dogs from Canada and the US were included; 79 from clinical infections and 28 from colonization sites. Thirty-nine (36%) isolates were susceptible to tetracycline, 41 (38%) to doxycycline and 70 (65%) to minocycline. Two main dru types, dt9a and dt11a, were present. When tetracycline or doxycycline resistant, dru type dt9a and related strains predominantly harboured tet(K) and were susceptible to minocycline. In contrast, dt11a and related strains tended to harbour tet(M), which confers resistance to all three tetracyclines. Minocycline might be a treatment option for some MRSP infections, even those that are doxycycline resistant; however, interpretive breakpoints may need to be re-assessed. Study of the pharmacokinetics and clinical efficacy of minocycline in dogs and cats is warranted.

  1. Direct-current vertical electrical-resistivity soundings in the Lower Peninsula of Michigan

    USGS Publications Warehouse

    Westjohn, D.B.; Carter, P.J.

    1989-01-01

    Ninety-three direct-current vertical electrical-resistivity soundings were conducted in the Lower Peninsula of Michigan from June through October 1987. These soundings were made to assist in mapping the depth to brine in areas where borehole resistivity logs and water-quality data are sparse or lacking. The Schlumberger array for placement of current and potential electrodes was used for each sounding. Vertical electrical-resistivity sounding field data, shifted and smoothed sounding data, and electric layers calculated using inverse modeling techniques are presented. Also included is a summary of the near-surface conditions and depths to conductors and resistors for each sounding location.

  2. A Modified Time-Delay Addition Method to Extract Resistive Leakage Current of MOSA

    NASA Astrophysics Data System (ADS)

    Khodsuz, Masume; Mirzaie, Mohammad

    2016-12-01

    Metal oxide surge arresters are one of the most important equipment for power system protection against switching and lightning over-voltages. High-energy stresses and environmental features are the main factors which degrade surge arresters. In order to verify surge arresters good condition, their monitoring is necessary. The majority of surge arrester monitoring techniques is based on total leakage current decomposition of their capacitive and resistive components. This paper introduces a new approach based on time-delay addition method to extract the resistive current from the total leakage current without measuring voltage signal. Surge arrester model for calculating leakage current has been performed in ATP-EMTP. In addition, the signal processing has been done using MATLAB software. To show the accuracy of the proposed method, experimental tests have been performed to extract resistive leakage current by the proposed method.

  3. [National evaluation of the diagnosis of activated protein C resistance].

    PubMed

    Montiel-Manzano, Guadalupe; de la Peña-Díaz, Aurora; Majluf-Cruz, Abraham; Cesarman-Maus, Gabriela; Corona-de la Peña, Norma; Cruz-Cruz, Donají; Gaminio, Elizabeth; Martínez-Murillo, Carlos; Mayagoitia, Teresa; Miranda-Peralta, Enrique; Poblete, Teresita; Quintana-Martínez, Sandra; Ramírez, Raúl; Razo, Daniel; Ruiz de Chávez-Ochoa, Adriana; Reyes-Núñez, Virginia Adriana; Salazar, Rosario; Vicencio-Santiago, Guadalupe Virginia; Villa, Rosario; Reyes-Núñez, Aurelia Virginia

    2003-01-01

    Thrombophilia or prothrombotic state appears when activation of blood hemostatic mechanisms overcomes the physiological anticoagulant capacity allowing a thrombotic event. Thrombosis is the leading worldwide mortality cause and due to its high associated morbidity and mortality, it should be insisted in the opportune identification of a thrombophilic state. The study of thrombophilia identifies individuals at high risk for thrombosis. This meeting was conceived first to analyze the current status of the diagnosis of thrombophilia in Mexico and second to create the base for a national consensus for thrombophilia screening and for the establishment of a national center for laboratory reference and quality control for thrombophilia. Since searching of activated protein C resistance (APCR) and FV Leiden seem to have priority either in the clinical setting and in public health services, it was decided to start with these two abnormalities as a model to analyze the current status of thrombophilia diagnosis in the clinical laboratory. At this time, several thrombophilic abnormalities have been described however, APCR remains the most important cause of thrombophilia, accounting for as much as 20% to 60% of all venous thrombosis. APCR is a consequence of the resistance of activated FV to be inactivated by activated protein C. Procoagulant activity of activated FV increases the risk of thrombosis. Hereditary APCR is almost always due to a point mutation at the nucleotide 1691 of the FV gen inducing an Arg506Glu substitution in FV molecule. This mutation is better known as FV Leiden. Heterocygous carriers of FV Leiden have a thrombotic risk 5 to 10 times higher than general population while the risk for the homocygote state is increased 50 to 100-fold. When activated PC is added to plasma from patients with FV Leiden, this last resists the anticoagulant effect of activated PC. Therefore, thrombin production is not inhibited. This phenomenon is called APCR. The functional

  4. Antimicrobial resistance among Enterobacteriaceae in South America: history, current dissemination status and associated socioeconomic factors.

    PubMed

    Bonelli, Raquel Regina; Moreira, Beatriz Meurer; Picão, Renata Cristina

    2014-04-01

    South America exhibits some of the higher rates of antimicrobial resistance in Enterobactericeae worldwide. This continent includes 12 independent countries with huge socioeconomic differences, where the ample access to antimicrobials, including counterfeit ones, coexists with ineffective health systems and sanitation problems, favoring the emergence and dissemination of resistant strains. This work presents a literature review concerning the evolution and current status of antimicrobial resistance threats found among Enterobacteriaceae in South America. Resistance to β-lactams, fluoroquinolones and aminoglycosides was emphasized along with description of key epidemiological studies that highlight the success of specific resistance determinants in different parts of the continent. In addition, a discussion regarding political and socioeconomic factors possibly related to the dissemination of antimicrobial resistant strains in clinical settings and at the community is presented. Finally, in order to assess the possible sources of resistant bacteria, we compile the current knowledge about the occurrence of antimicrobial resistance in isolates in South American' food, food-producing animals and off-hospitals environments. By addressing that intensive intercontinental commerce and tourism neutralizes the protective effect of geographic barriers, we provide arguments reinforcing that globally integrated efforts are needed to decelerate the emergence and dissemination of antimicrobial resistant strains.

  5. Enterococci from Bangkok, Thailand, with high-level resistance to currently available aminoglycosides.

    PubMed Central

    Murray, B E; Tsao, J; Panida, J

    1983-01-01

    Enterococcal endocarditis is usually treated with a combination of a penicillin and an aminoglycoside. Recent reports have documented the emergence of enterococci in France with high-level resistance to gentamicin, tobramycin, and kanamycin and the emergence of strains in Houston, Tex. with high-level resistance to all of these drugs and streptomycin. In this study, we examined strains from a geographic area where newer aminoglycosides have been less commonly used. Of 125 distinct patient isolates, 18 (14%) were resistant to greater than 2,000 micrograms of gentamicin and most other aminoglycosides per ml. Four of these strains transferred gentamicin resistance to a laboratory recipient. One strain, chosen for further study, was resistant to synergism between penicillin and gentamicin, tobramycin, kanamycin, streptomycin, and amikacin and demonstrated the following enzymatic activities: 3'- and 2"-aminoglycoside phosphotransferases, 6'-aminoglycoside acetyltransferase, and adenylylation of streptomycin. Optimal therapy for endocarditis caused by such highly resistant strains is currently unknown. PMID:6614889

  6. Current trends of human infections and antibiotic resistance of the genus Shewanella.

    PubMed

    Yousfi, K; Bekal, S; Usongo, V; Touati, A

    2017-03-15

    Shewanella spp. are commonly known as environmental bacteria and are most frequently isolated from aquatic areas. Currently, diseases syndromes and multidrug resistance have increasingly been reported in the genus Shewanella. Some species are associated with various infections, such as skin and soft tissue infections, as well as bacteremia. Generally, these bacteria are opportunistic and mostly affect people with an impaired immune system. This genus is also a probable vehicle and progenitor of antibiotic resistance genes. In fact, several resistance genes and mobile genetic elements have been identified in some resistant species isolated from environmental or clinical settings. These genes confer resistance to different antibiotic classes, including those used in therapies such as β-lactams and quinolones, and are generally located on the chromosome. Recently, a multidrug-resistant (MDR) plasmid harboring several drug resistance genes associated with transposons and integrons has been identified in Shewanella xiamenensis. These antibiotic resistance genes can circulate in the environment and contribute to the emergence of antibiotic resistance. This review describes different aspects of Shewanella, focusing on the infections caused by this genus, as well as their role in the propagation of antibiotic resistance via mobile genetic elements.

  7. Current-induced forces: a new mechanism to induce negative differential resistance and current-switching effect in molecular junctions.

    PubMed

    Gu, Lei; Fu, Hua-Hua

    2015-12-04

    Current-induced forces can excite molecules, polymers and other low-dimensional materials, which in turn leads to an effective gate voltage through Holstein interaction. Here, by taking a short asymmetric DNA junction as an example, and using the Langevin approach, we find that when suppression of charge transport by the effective gate voltage surpasses the current increase from an elevated voltage bias, the current-voltage (I-V) curves display strong negative differential resistance (NDR) and perfect current-switching characteristics. The asymmetric DNA chain differs in mechanical stability under inverse voltages and the I-V curve is asymmetric about inverse biases, which can be used to understand recent transport experiments on DNA chains, and meanwhile provides a new strategy to realize NDR in molecular junctions and other low-dimensional quantum systems.

  8. Neonatal infections due to multi-resistant strains: Epidemiology, current treatment, emerging therapeutic approaches and prevention.

    PubMed

    Tzialla, Chryssoula; Borghesi, Alessandro; Pozzi, Margherita; Stronati, Mauro

    2015-12-07

    Severe infections represent the main cause of neonatal mortality accounting for more than one million neonatal deaths worldwide every year. Antibiotics are the most commonly prescribed medications in neonatal intensive care units. The benefits of antibiotic therapy when indicated are clearly enormous, but the continued and widespread use of antibiotics has generated over the years a strong selective pressure on microorganisms, favoring the emergence of resistant strains. Health agencies worldwide are galvanizing attention toward antibiotic resistance in gram-positive and gram-negative bacteria. Infections in neonatal units due to multidrug and extensively multidrug resistant bacteria are rising and are already seriously challenging antibiotic treatment options. While there is a growing choice of agents against multi-resistant gram-positive bacteria, new options for multi-resistant gram-negative bacteria in the clinical practice have decreased significantly in the last 20 years making the treatment of infections caused by multidrug-resistant pathogens challenging mostly in neonates. Treatment options are currently limited and will be some years before any new treatment for neonates become available for clinical use, if ever. The aim of the review is to highlight the current knowledge on antibiotic resistance in the neonatal population, the possible therapeutic choices, and the prevention strategies to adopt in order to reduce the emergency and spread of resistant strains.

  9. Methods for Specific Electrode Resistance Measurement during Transcranial Direct Current Stimulation

    PubMed Central

    Khadka, Niranjan; Rahman, Asif; Sarantos, Chris; Truong, Dennis Q.; Bikson, Marom

    2014-01-01

    Background Transcranial Direct Current Stimulation (tDCS) is investigated to treat a wide range of neuropsychiatric disorders, for rehabilitation, and for enhancing cognitive performance. The monitoring of electrode resistance before and during tDCS is considered important for tolerability and safety, where an unusually high resistance is indicative of undesired electrode or poor skin contact conditions. Conventional resistance measurement methods do not isolate individual electrode resistance but rather measures overall voltage. Moreover, for HD-tDCS devices, cross talk across electrodes makes concurrent resistance monitoring unreliable. Objective We propose a novel method for monitoring of the individual electrode resistance during tDCS, using a super-position of direct current with a test-signal (low-intensity and low-frequency sinusoids with electrode– specific frequencies) and a single sentinel electrode (not used for DC). Methods To validate this methodology, we developed lumped-parameter models of two and multi-electrode tDCS. Approaches with and without a sentinel electrode were solved and underlying assumptions identified. Assumptions were tested and parameterized in healthy participants using forearm stimulation combining tDCS (2 mA) and sinusoidal test-signals (38 μA and 76 μA peak to peak at 1 Hz, 10 Hz, and 100 Hz) and an in vitro test (where varied electrode failure modes were created). DC and AC component voltages across the electrodes were compared and participants were asked to rate subjective pain. Results A sentinel electrode is required to isolate electrode resistance in a two-electrode tDCS system. For multi-electrode resistance tracking, cross talk was aggravated with electrode proximity and current/resistance mismatches, but could be corrected using proposed approaches. Average voltage and average pain scores were not significantly different across test current intensities and frequencies (two-way repeated measures ANOVA) indicating the

  10. Evaluation of current regulations and real accident conditions

    SciTech Connect

    Fischer, L.E.; Kimura, C.Y.; Witte, M.C.

    1985-04-05

    In order to improve estimates of the effectiveness of current regulatory standards, a program was initiated by the US Nuclear Regulatory Commission (NRC) to have the Lawrence Livermore Laboratory (LLNL) evaluate regulatory standards against real world accident conditions. This paper presents the results of the evaluation performed for the hypothetical 30-foot drop onto an unyielding surface and real world impact conditions which might be experienced by a spent fuel cask being transported by a truck. The results of the evaluations performed for other pertinent accident conditions for truck and train transport will be documented at the conclusion of the program. 10 refs., 8 figs., 3 tabs.

  11. Implementation of an active instructional design for teaching the concepts of current, voltage and resistance

    NASA Astrophysics Data System (ADS)

    Orlaineta-Agüero, S.; Del Sol-Fernández, S.; Sánchez-Guzmán, D.; García-Salcedo, R.

    2017-01-01

    In the present work we show the implementation of a learning sequence based on an active learning methodology for teaching Physics, this proposal tends to promote a better learning in high school students with the use of a comic book and it combines the use of different low-cost experimental activities for teaching the electrical concepts of Current, Resistance and Voltage. We consider that this kind of strategy can be easily extrapolated to higher-education levels like Engineering-college/university level and other disciplines of Science. To evaluate this proposal, we used some conceptual questions from the Electric Circuits Concept Evaluation survey developed by Sokoloff and the results from this survey was analysed with the Normalized Conceptual Gain proposed by Hake and the Concentration Factor that was proposed by Bao and Redish, to identify the effectiveness of the methodology and the models that the students presented after and before the instruction, respectively. We found that this methodology was more effective than only the implementation of traditional lectures, we consider that these results cannot be generalized but gave us the opportunity to view many important approaches in Physics Education; finally, we will continue to apply the same experiment with more students, in the same and upper levels of education, to confirm and validate the effectiveness of this methodology proposal.

  12. Evaluation of Current Assessment Methods in Engineering Entrepreneurship Education

    ERIC Educational Resources Information Center

    Purzer, Senay; Fila, Nicholas; Nataraja, Kavin

    2016-01-01

    Quality assessment is an essential component of education that allows educators to support student learning and improve educational programs. The purpose of this study is to evaluate the current state of assessment in engineering entrepreneurship education. We identified 52 assessment instruments covered in 29 journal articles and conference…

  13. Resistive wall heating due to image current on the beam chamber for a superconducting undulator.

    SciTech Connect

    Kim, S. H. )

    2012-03-27

    The image-current heating on the resistive beam chamber of a superconducting undulator (SCU) was calculated based on the normal and anomalous skin effects. Using the bulk resistivity of copper for the beam chamber, the heat loads were calculated for the residual resistivity ratios (RRRs) of unity at room temperature to 100 K at a cryogenic temperature as the reference. Then, using the resistivity of the specific aluminum alloy 6053-T5, which will be used for the SCU beam chamber, the heat loads were calculated. An electron beam stored in a storage ring induces an image current on the inner conducting wall, mainly within a skin depth, of the beam chamber. The image current, with opposite charge to the electron beam, travels along the chamber wall in the same direction as the electron beam. The average current in the storage ring consists of a number of bunches. When the pattern of the bunched beam is repeated according to the rf frequency, the beam current may be expressed in terms of a Fourier series. The time structure of the image current is assumed to be the same as that of the beam current. For a given resistivity of the chamber inner wall, the application ofthe normal or anomalous skin effect will depend on the harmonic numbers of the Fourier series of the beam current and the temperature of the chamber. For a round beam chamber with a ratius r, much larger than the beam size, one can assume that the image current density as well as the density square, may be uniform around the perimeter 2{pi}r. For the SCU beam chamber, which has a relatively narrow vertical gap compared to the width, the effective perimeter was estimated since the heat load should be proportional to the inverse of the perimeter.

  14. Current driven tri-stable resistance states in magnetic point contacts.

    PubMed

    Yanson, I K; Fisun, V V; Naidyuk, Yu G; Balkashin, O P; Triputen, L Yu; Konovalenko, A; Korenivski, V

    2009-09-02

    Point contacts between normal and ferromagnetic metals are investigated using magnetoresistance and transport spectroscopy measurements combined with micromagnetic simulations. Pronounced hysteresis in the point contact resistance versus both bias current and external magnetic field are observed. It is found that such hysteretic resistance can exhibit, in addition to bi-stable resistance states found in ordinary spin valves, tri-stable resistance states with a middle resistance level. We interpret these observations in terms of surface spin valve and spin vortex states, originating from a substantially modified spin structure at the ferromagnetic interface in the contact core. We argue that these surface spin states, subject to a weakened exchange interaction, dominate the effects of spin transfer torques on the nanometer scale.

  15. Nondestructive evaluation of composite materials by electrical resistance measurement

    NASA Astrophysics Data System (ADS)

    Mei, Zhen

    This dissertation investigates electrical resistance measurement for nondestructive evaluation of carbon fiber (CF) reinforced polymer matrix composites. The method involves measuring the DC electrical resistance in either the longitudinal or through thickness direction. The thermal history and thermal properties of thermoplastic/CF composites were studied by longitudinal and through-thickness resistance measurements. The resistance results were consistent with differential scanning calorimetry (DSC) and thermomechanical analysis (TMA) results. The resistance measurements gave more information on the melting of the polymer matrix than TMA. They were more sensitive to the glass transition of the polymer matrix than DSC. The through-thickness resistance decreased as autohesion progressed. The activation energy of autohesion was 21.2 kJ/mol for both nylon-6 and polyphenylene sulfide (PPS)/CF composites. Adhesive bonding and debonding were monitored in real-time by measurement of the through-thickness resistance between the adherends in an adhesive joint during heating and subsequent cooling. Debonding occurred during cooling when the pressure or temperature during prior bonding was not sufficiently high. A long heating time below the melting temperature (T m) was found to be detrimental to subsequent PPS adhesive joint development above Tm, due to curing reactions below Tm and consequent reduced mass flow response above Tm. A high heating rate (small heating time) enhanced the bonding more than a high pressure. The longitudinal resistance measurement was used to investigate the effects of temperature and stress on the interface between a concrete substrate and its epoxy/CF composite retrofit. The resistance of the retrofit was increased by bond degradation, whether the degradation was due to heat or stress. The degradation was reversible. Irreversible disturbance in the fiber arrangement occurred slightly as thermal or load cycling occurred, as indicated by the

  16. Antimicrobial resistance in Helicobacter pylori: current situation and management strategy in Vietnam.

    PubMed

    Phan, Trung Nam; Tran, Van Huy; Tran, Thi Nhu Hoa; Le, Van An; Santona, Antonella; Rubino, Salvatore; Paglietti, Bianca

    2015-07-04

    Increasing antimicrobial resistance to key antibiotics in Helicobacter pylori has become a main cause of treatment failures in many countries, including Vietnam. For this reason it is advisable to perform antimicrobial sensitivity tests to provide more focused regimens for H. pylori eradication. However, this approach is generally unavailable for H. pylori in Vietnam and the selection of treatment regimens is mainly based on the trend of antibiotic use in the population, resistance development in the region, and history of H. pylori eradication of patients. The aim of this review is to examine the current situation of antimicrobial resistance in Vietnam and suggest management strategies for treatment selection.

  17. Use of Monte Carlo simulation to evaluate the development of vancomycin resistance in meticillin-resistant Staphylococcus aureus.

    PubMed

    Mei, Qing; Ye, Ying; Zhu, Yu-lin; Cheng, Jun; Yang, Hai-fei; Liu, Yan-yan; Li, Hong-ru; Li, Jia-bin

    2015-06-01

    Monte Carlo simulations were performed for various vancomycin dosage regimens to evaluate the potential for development of vancomycin resistance in meticillin-resistant Staphylococcus aureus (MRSA). When the target of free AUC(24)/MIC≥200 was considered (where AUC(24) is the area under the drug concentration-time curve in a 24-h interval and MIC is the minimum inhibitory concentration), a standard dose regimen (1000 mg every 12 h) yielded unacceptable simulated outcomes in patients with normal renal function; in particular, the probability of target attainment (PTA) was only 30.5% at an MIC of 1mg/L. For the same dosage regimens and the mutant prevention concentration (MPC)-based pharmacokinetic target (total AUC(24)/MPC>15), the cumulative fraction of response exceeded 80% for all renal function strata; low values of PTA (<80%) were obtained only for isolates with MPCs of ≥22.4 mg/L, which consisted of all 21 strains of heterogeneous vancomycin-intermediate S. aureus (hVISA) and a handful of non-hVISA strains with MICs of 2mg/L (32%; 16/50). Based on the current status of vancomycin resistance, we conclude that total AUC(24)/MPC>15, derived from in vivo experiments, is more suitable to predict the development of vancomycin resistance. In clinical practice, individualised vancomycin therapy should be considered to minimise selection of resistance mutations.

  18. Evaluation of antimicrobial resistance of bovine bacteria to antibiotics

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antimicrobial resistance (AMR) is one of the most formidable threats to human medicine today. Therefore, the research objective is to evaluate the susceptibility of Staphylococcus species isolated from beef cows to 12 antibiotics commonly used in treating human and animal infections. This research w...

  19. Soybean lines evaluated for resistance to reniform nematode

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Seventy-four wild and domestic soybean (Glycine max and G. soja) lines were evaluated for resistance to reniform nematode (Rotylenchulus reniformis) in growth chamber tests with a day length of 16 hours and temperature held constant at 28 C. Several entries for which reactions to reniform nematode w...

  20. HIGH RESOLUTION RESISTIVITY LEAK DETECTION DATA PROCESSING & EVALUATION MEHTODS & REQUIREMENTS

    SciTech Connect

    SCHOFIELD JS

    2007-10-04

    This document has two purposes: {sm_bullet} Describe how data generated by High Resolution REsistivity (HRR) leak detection (LD) systems deployed during single-shell tank (SST) waste retrieval operations are processed and evaluated. {sm_bullet} Provide the basic review requirements for HRR data when Hrr is deployed as a leak detection method during SST waste retrievals.

  1. An electromagnetic microscope for eddy current evaluation of materials

    SciTech Connect

    Podney, W.N.; Czipott, P.V. )

    1991-03-01

    This paper presents the concept of a new instrument for nondestructive evaluation (NDE). Called an electromagnetic microscope, formed by superconductive microprobes arrayed in parallel rows. When moved over a test piece, the array generates a scanned image of flaws, stress variations, or changes in composition. Each microprobe comprises drive coils a few mm in radius that encircle pickup loops forming a concentric, coplanar gradiometer 1 mm or less in diameter coupled to a superconducting quantum interference device (SQUID). Drive coils transmit an oscillating magnetic field that induces eddy or magnetization currents in conductive or ferromagnetic materials, respectively. The gradiometer senses distortions in paths of induced currents.

  2. Thiamethoxam Resistance in the House Fly, Musca domestica L.: Current Status, Resistance Selection, Cross-Resistance Potential and Possible Biochemical Mechanisms.

    PubMed

    Khan, Hafiz Azhar Ali; Akram, Waseem; Iqbal, Javaid; Naeem-Ullah, Unsar

    2015-01-01

    The house fly, Musca domestica L., is an important ectoparasite with the ability to develop resistance to insecticides used for their control. Thiamethoxam, a neonicotinoid, is a relatively new insecticide and effectively used against house flies with a few reports of resistance around the globe. To understand the status of resistance to thiamethoxam, eight adult house fly strains were evaluated under laboratory conditions. In addition, to assess the risks of resistance development, cross-resistance potential and possible biochemical mechanisms, a field strain of house flies was selected with thiamethoxam in the laboratory. The results revealed that the field strains showed varying level of resistance to thiamethoxam with resistance ratios (RR) at LC50 ranged from 7.66-20.13 folds. Continuous selection of the field strain (Thia-SEL) for five generations increased the RR from initial 7.66 fold to 33.59 fold. However, resistance declined significantly when the Thia-SEL strain reared for the next five generations without exposure to thiamethoxam. Compared to the laboratory susceptible reference strain (Lab-susceptible), the Thia-SEL strain showed cross-resistance to imidacloprid. Synergism tests revealed that S,S,S-tributylphosphorotrithioate (DEF) and piperonyl butoxide (PBO) produced synergism of thiamethoxam effects in the Thia-SEL strain (2.94 and 5.00 fold, respectively). In addition, biochemical analyses revealed that the activities of carboxylesterase (CarE) and mixed function oxidase (MFO) in the Thia-SEL strain were significantly higher than the Lab-susceptible strain. It seems that metabolic detoxification by CarE and MFO was a major mechanism for thiamethoxam resistance in the Thia-SEL strain of house flies. The results could be helpful in the future to develop an improved control strategy against house flies.

  3. Sn-Ag-Cu to Cu joint current aging test and evolution of resistance and microstructure

    NASA Astrophysics Data System (ADS)

    Xu, Di Erick; Chow, Jasper; Mayer, Michael; Jung, Jae Pil; Yoon, Jong Hyun

    2015-11-01

    SAC 305 solder bump with 800 μm diameter were produced and soldered to a custom substrate with Cu lines as leads that allow for resistance measurement during current aging. The measured joint resistance values (leads plus solder bump) before aging are 7.7 ± 1.8 mΩ and 11.8 ± 2.8 mΩ at room temperature and 160°C, respectively. In general, the resistance of the solder joint increases instantly by about 1 mΩ, when subjected to a 2.2 A aging current at 160°C. The increase is gradual in the following hours of aging and more drastic as it approaches the final failure. Four stages are identified in the resistance signal curve and compared with observations from cross sections. The stages are IMC growth, crack formation and propagation, intermittent crack healing-forming, and final failure resulting in an open connection at the cathode. Recently a periodical drop and rise behavior was reported for the resistance signal. This behavior is reproduced and attributed to the intermittent crack healing-forming stage. The healing events observed are faster than the sampling time. Possibly, as current is concentrated when bypassing interfacial cracks, local melting occurs partially filling cracks before resolidifying. [Figure not available: see fulltext.

  4. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander A.

    2014-01-01

    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  5. Insulation Resistance and Leakage Currents in Low-Voltage Ceramic Capacitors with Cracks

    NASA Technical Reports Server (NTRS)

    Teverovsky, Alexander A.

    2016-01-01

    Measurement of insulation resistance (IR) in multilayer ceramic capacitors (MLCCs) is considered a screening technique that ensures the dielectric is defect-free. This work analyzes the effectiveness of this technique for revealing cracks in ceramic capacitors. It is shown that absorption currents prevail over the intrinsic leakage currents during standard IR measurements at room temperature. Absorption currents, and consequently IR, have a weak temperature dependence, increase linearly with voltage (before saturation), and are not sensitive to the presence of mechanical defects. In contrary, intrinsic leakage currents increase super-linearly with voltage and exponentially with temperature (activation energy is in the range from 0.6 eV to 1.1 eV). Leakage currents associated with the presence of cracks have a weaker dependence on temperature and voltage compared to the intrinsic leakage currents. For this reason, intrinsic leakage currents prevail at high temperatures and voltages, thus masking the presence of defects.

  6. Endocrine therapy resistance in breast cancer: current status, possible mechanisms and overcoming strategies.

    PubMed

    Fan, Weimin; Chang, Jinjia; Fu, Peifeng

    2015-08-01

    Endocrine therapy has become one of most effective forms of targeted adjuvant therapy for hormone-sensitive breast cancer and may be given after surgery or radiotherapy, and also prior, or subsequent to chemotherapy. Current commonly used drugs for adjuvant endocrine therapy can be divided into following three classes: selective estrogen receptor modulators, aromatase inhibitors and selective estrogen receptor downregulators. Tumor cells can develop resistance to endocrine therapy, a major obstacle limiting the success of breast cancer treatment. The complicated crosstalk, both genomic and nongenomic, between estrogen receptors and growth factors was considered to be a crucial factor contributing to endocrine resistance. However, resistance to this therapy is thought to be a progressive, step-wise process, and the underlying mechanism remains unclear. In this review, we summarize the possible biological and molecular mechanisms that underlie endocrine resistance, and discuss some novel strategies to overcoming these issues.

  7. Low-energy Resistive Random Access Memory Devices with No Need for a Compliance Current

    PubMed Central

    Xu, Zedong; Yu, Lina; Wu, Yong; Dong, Chang; Deng, Ning; Xu, Xiaoguang; Miao, J.; Jiang, Yong

    2015-01-01

    A novel resistive random access memory device is designed with SrTiO3/ La2/3Sr1/3MnO3 (LSMO)/MgAl2O4 (MAO)/Cu structure, in which metallic epitaxial LSMO is employed as the bottom electrode rather than traditional metal materials. In this device, the critical external compliance current is no longer necessary due to the high self-resistance of LSMO. The LMSO bottom electrode can act as a series resistor to offer a compliance current during the set process. Besides, the device also has excellent switching features which are originated in the formation of Cu filaments under external voltage. Therefore it provides the possibility of reducing power consumption and accelerating the commercialization of resistive switching devices. PMID:25982101

  8. Development and fabrication of low ON resistance high current vertical VMOS power FETs

    NASA Technical Reports Server (NTRS)

    Kay, S.

    1979-01-01

    The design of a VMOS Power FET exhibiting low ON resistance, high current as well as high breakdown voltage and fast switching speeds is described. The design which is based on a 1st-order device model, features a novel polysilicon-gate structure and fieldplated groove termination to achieve high packing density and high breakdown voltage, respectively. One test chip, named VNTKI, can block 180 V at an ON resistence of 2.5 ohm. A 150 mil x 200 mil (.19 sq cm) experimental chip has demonstrated a breakdown voltage of 200v, an ON resistance of 0.12 ohm, a switching time of less than 100 ns, and a pulse drain - current of 50 A with 10 V gate drive.

  9. A new low voltage level-shifted FVF current mirror with enhanced bandwidth and output resistance

    NASA Astrophysics Data System (ADS)

    Aggarwal, Bhawna; Gupta, Maneesha; Gupta, Anil Kumar; Sangal, Ankur

    2016-10-01

    This paper proposes a new high-performance level-shifted flipped voltage follower (LSFVF) based low-voltage current mirror (CM). The proposed CM utilises the low-supply voltage and low-input resistance characteristics of a flipped voltage follower (FVF) CM. In the proposed CM, level-shifting configuration is used to obtain a wide operating current range and resistive compensation technique is employed to increase the operating bandwidth. The peaking in frequency response is reduced by using an additional large MOSFET. Moreover, a very high output resistance (in GΩ range) along with low-current transfer error is achieved through super-cascode configuration for a wide current range (0-440 µA). Small signal analysis is carried out to show the improvements achieved at each step. The proposed CM is simulated by Mentor Graphics Eldospice in TSMC 0.18 µm CMOS, BSIM3 and Level 53 technology. In the proposed CM, a bandwidth of 6.1799 GHz, 1% settling time of 0.719 ns, input and output resistances of 21.43 Ω and 1.14 GΩ, respectively, are obtained with a single supply voltage of 1 V. The layout of the proposed CM has been designed and post-layout simulation results have been shown. The post-layout simulation results for Monte Carlo and temperature analysis have also been included to show the reliability of the CM against the variations in process parameters and temperature changes.

  10. Mycoplasma genitalium infection: current treatment options, therapeutic failure, and resistance-associated mutations

    PubMed Central

    Couldwell, Deborah L; Lewis, David A

    2015-01-01

    Mycoplasma genitalium is an important cause of non-gonococcal urethritis, cervicitis, and related upper genital tract infections. The efficacy of doxycycline, used extensively to treat non-gonococcal urethritis in the past, is relatively poor for M. genitalium infection; azithromycin has been the preferred treatment for several years. Research on the efficacy of azithromycin has primarily focused on the 1 g single-dose regimen, but some studies have also evaluated higher doses and longer courses, particularly the extended 1.5 g regimen. This extended regimen is thought to be more efficacious than the 1 g single-dose regimen, although the regimens have not been directly compared in clinical trials. Azithromycin treatment failure was first reported in Australia and has subsequently been documented in several continents. Recent reports indicate an upward trend in the prevalence of macrolide-resistant M. genitalium infections (transmitted resistance), and cases of induced resistance following azithromycin therapy have also been documented. Emergence of antimicrobial-resistant M. genitalium, driven by suboptimal macrolide dosage, now threatens the continued provision of effective and convenient treatments. Advances in techniques to detect resistance mutations in DNA extracts have facilitated correlation of clinical outcomes with genotypic resistance. A strong and consistent association exists between presence of 23S rRNA gene mutations and azithromycin treatment failure. Fluoroquinolones such as moxifloxacin, gatifloxacin, and sitafloxacin remain highly active against most macrolide-resistant M. genitalium. However, the first clinical cases of moxifloxacin treatment failure, due to bacteria with coexistent macrolide-associated and fluoroquinolone-associated resistance mutations, were recently published by Australian investigators. Pristinamycin and solithromycin may be of clinical benefit for such multidrug-resistant infections. Further clinical studies are required to

  11. The evaluation of rock permeability with streaming current measurements

    NASA Astrophysics Data System (ADS)

    Wang, Jun; Hu, Hengshan; Guan, Wei

    2016-09-01

    Rock permeability is an important parameter for the formation evaluation. In this paper, a new method with streaming current is proposed to determine the sample permeability based on the electrokinetic effects, and is proved by the experimental measurements. Corresponding to this method, we have designed an experimental setup and a test system, then performed the streaming current (potential) and electro-osmosis pressure experiments with 23 sandstone samples at 0.05 mol l-1 NaCl solution. The streaming current (potential) coefficient and electro-osmosis pressure coefficient are obtained, respectively, with the experimental data at low frequencies with AC lock-in technique. The electrokinetic permeabilities are further calculated with these coefficients. The results are consistent well with the gas permeability measured with Darcy's law, which verifies the current method for estimating rock permeability. Our measurements are also analysed and compared with previous measurements. The results indicate that our method can reflect the essence of electrokinetic effects better and simplify the electrokinetic measurements as well. In addition, we discuss the influences of experimental artefacts (core holder and confining pressure installation) on the electrokinetic data. The results show that the trough phenomenon, appeared in frequency curves of streaming current (potential) coefficients, is induced by the resonance of the core-holder/vibrator system. This is important for the design of electrokinetic setup and the analysis of low-frequency response of the electrokinetic coupling coefficients.

  12. Effects of neomycin on high-threshold Ca(2+) currents and tetrodotoxin-resistant Na(+) currents in rat dorsal root ganglion neuron.

    PubMed

    Zhou, Yu; Zhao, Zhi-Qi

    2002-08-16

    High-threshold Ca(2+) channels and tetrodotoxin-resistant Na(+) channels are highly expressed in small dorsal root ganglion neurons. In acutely isolated rat dorsal root ganglion neurons, the effects of neomycin, one of the aminoglycoside antibiotics, on high-threshold Ca(2+) currents and tetrodotoxin-resistant Na(+) currents were examined using whole-cell patch recording. We showed for the first time that neomycin dose-dependently inhibited peak high-threshold Ca(2+) currents and peak tetrodotoxin-resistant Na(+) currents with half-maximal inhibitory concentrations at 3.69 microM (n=20) and 1213.44 microM (n=25), respectively. Inactivation properties of high-threshold Ca(2+) currents and activation properties of tetrodotoxin-resistant Na(+) currents were also affected by neomycin with reduction of excitability of small dorsal root ganglion neurons. Half-maximal inactivation voltage of high-threshold Ca(2+) currents was -45.56 mV before and -50.46 mV after application of neomycin (n=10). Half-maximal activation voltage of tetrodotoxin-resistant Na(+) currents was -19.93 mV before and -11.19 mV after administration of neomycin (n=15). These results suggest that neomycin can inhibit high-threshold Ca(2+) currents and tetrodotoxin-resistant Na(+) currents in small dorsal root ganglion neurons, which may contribute to neomycin-induced peripheral and central analgesia.

  13. Disease resistance breeding in rose: current status and potential of biotechnological tools.

    PubMed

    Debener, Thomas; Byrne, David H

    2014-11-01

    The cultivated rose is a multispecies complex for which a high level of disease protection is needed due to the low tolerance of blemishes in ornamental plants. The most important fungal diseases are black spot, powdery mildew, botrytis and downy mildew. Rose rosette, a lethal viral pathogen, is emerging as a devastating disease in North America. Currently rose breeders use a recurrent phenotypic selection approach and perform selection for disease resistance for most pathogen issues in a 2-3 year field trial. Marker assisted selection could accelerate this breeding process. Thus far markers have been identified for resistance to black spot (Rdrs) and powdery mildew and with the ability of genotyping by sequencing to generate 1000s of markers our ability to identify markers useful in plant improvement should increase exponentially. Transgenic rose lines with various fungal resistance genes inserted have shown limited success and RNAi technology has potential to provide virus resistance. Roses, as do other plants, have sequences homologous to characterized R-genes in their genomes, some which have been related to specific disease resistance. With improving next generation sequencing technology, our ability to do genomic and transcriptomic studies of the resistance related genes in both the rose and the pathogens to reveal novel gene targets to develop resistant roses will accelerate. Finally, the development of designer nucleases opens up a potentially non-GMO approach to directly modify a rose's DNA to create a disease resistant rose. Although there is much potential, at present rose breeders are not using marker assisted breeding primarily because a good suite of marker/trait associations (MTA) that would ensure a path to stable disease resistance is not available. As our genomic analytical tools improve, so will our ability to identify useful genes and linked markers. Once these MTAs are available, it will be the cost savings, both in time and money, that will

  14. Slime thickness evaluation of bored piles by electrical resistivity probe

    NASA Astrophysics Data System (ADS)

    Chun, Ok-Hyun; Yoon, Hyung-Koo; Park, Min-Chul; Lee, Jong-Sub

    2014-09-01

    The bottoms of bored piles are generally stacked with soil particles, both while boreholes are being drilled, and afterward. The stacked soils are called slime, and when loads are applied on the pile, increase the pile settlement. Thus to guarantee the end bearing capacity of bored piles, the slime thickness should be precisely detected. The objective of this study is to suggest a new method for evaluating the slime thickness, using temperature compensated electrical resistivity. Laboratory studies are performed in advance, to estimate and compare the resolution of the electrical resistivity probe (ERP) and time domain reflectometry (TDR). The electrical properties of the ERP and TDR are measured using coaxial type electrodes and parallel type two-wire electrodes, respectively. Penetration tests, conducted in the fully saturated sand-clay mixtures, demonstrate that the ERP produces a better resolution of layer detection than TDR. Thus, field application tests using the ERP with a diameter of 35.7 mm are conducted for the investigation of slime thickness in large diameter bored piles. Field tests show that the slime layers are clearly identified by the ERP: the electrical resistivity dramatically increases at the interface between the slurry and slime layer. The electrical resistivity in the slurry layer inversely correlates with the amount of circulated water. This study suggests that the new electrical resistivity method may be a useful method for the investigation of the slime thickness in bored piles.

  15. Rheological evaluation of simulated neutralized current acid waste

    SciTech Connect

    Fow, C.L.; McCarthy, D.; Thornton, G.T.

    1986-06-01

    A byproduct of the Purex process is an aqueous waste stream that contains fission products. This waste stream, called current acid waste, is chemically neutralized and stored in double shell tanks on the Hanford Site. This neutralized current acid waste (NCAW) will be transported by pipe to B-Plant, a processing plant on the Hanford Site. Rheological and transport properties of NCAW slurry were evaluated. First, researchers conducted lab rheological evaluations of simulated NCAW. The results of these evaluations were then correlated with classical rheological models and scaled up to predict the performance that is likely to occur in the full-scale system. The NCAW in the tank will either be retrieved as is, i.e., no change in the concentration presently in the tank, or will be slightly concentrated before retrieval. Sluicing may be required to retrieve the solids. Three concentrations of simulated NCAW were evaluated that would simulate the different retrieval options: NCAW in the concentration that is presently in the tank; a slightly concentrated NCAW, called NCAW5.5; and equal parts of NCAW settled solids and water (simulating the sluicing stage), called NCAW1:1. The physical and rheological properties of three samples of each concentration at 25 and 100/sup 0/C were evaluated in the laboratory. The properties displayed by NCAW and NCAW5.5 at 25 and 100/sup 0/C allowed it to be classified as a pseudoplastic non-Newtonian fluid. NCAW1:1 at 25 and 100/sup 0/C displayed properties of a yield-pseudoplastic non-Newtonian fluid. The classical non-Newtonian models for pseudoplastic and yield-pseudoplastic fluids were used with the laboratory data to predict the full-scale pump-pipe network parameters.

  16. EVALUATION AND RECOMMENDATION OF SALTSTONE MIXER AUGER/PADDLES MATERIALS OF CONSTRUCTION FOR IMPROVED WEAR RESISTANCE

    SciTech Connect

    Mickalonis, J.; Torres, R.

    2012-08-15

    Wear and corrosion testing were conducted to evaluate alternate materials of construction for the Saltstone mixer auger and paddles. These components have been degraded by wear from the slurry processed in the mixer. Material test options included PVD coatings (TiN, TiCN, and ZrN), weld overlays (Stellite 12 and Ultimet) and higher hardness steels and carbides (D2 and tungsten carbide). The corrosion testing demonstrated that the slurry is not detrimental to the current materials of construction or the new candidates. The ASTM G75 Miller wear test showed that the high hardness materials and the Stellite 12 weld overlay provide superior wear relative to the Astralloy and CF8M stainless steel, which are the current materials of construction, as well as the PVD coatings and Ultimet. The following recommendations are made for selecting new material options and improving the overall wear resistance of the Saltstone mixer components: A Stellite 12 weld overlay or higher hardness steel (with toughness equivalent to Astralloy) be used to improve the wear resistance of the Saltstone mixer paddles; other manufacturing specifications for the mixer need to be considered in this selection. The current use of the Stellite 12 weld overlay be evaluated so that coverage of the 316 auger can be optimized for improved wear resistance of the auger. The wear surfaces of the Saltstone mixer auger and paddles be evaluated so that laboratory data can be better correlated to actual service. The 2-inch Saltstone mixer prototype be used to verify material performance.

  17. Current review of antimicrobial treatment of nosocomial pneumonia caused by multidrug-resistant pathogens.

    PubMed

    Jean, Shio-Shin; Hsueh, Po-Ren

    2011-10-01

    Nosocomial pneumonia (including ventilator-associated pneumonia; VAP), a consistently difficult-to-treat entity, is frequently caused by multidrug-resistant (MDR) or pandrug-resistant (PDR) bacteria. Given the high mortality rates caused by drug-resistant bacteria and the difficulty of developing new potent antibiotics to target the problematic pathogens, combination regimens are under ardent evaluation as new strategies to overcome increasing drug resistance. Adjustment of the administration method of certain β-lactams (meropenem, or imipenem/cilastatin), or combination of tigecycline with some agents, may show promise with regard to successful management of MDR or PDR Acinetobacter baumannii pneumonia. Additionally, vancomycin plus rifampicin is an effective regimen against nosocomial pneumonia caused by methicillin-resistant Staphylococcus aureus (MRSA) responding poorly to vancomycin monotherapy. The clinical appropriateness of parenteral colistin against pneumonia caused by MDR A. baumannii has been established in a clinical trial. Facing the decline of clinical vancomycin efficacy after initial use, linezolid might be the drug of choice with regard to the treatment of MRSA-VAP. The role of tigecycline monotherapy for the management of nosocomial pneumonia caused by MRSA and extended-spectrum β-lactamase-producing Enterobacteriaceae needs to be cautiously evaluated.

  18. The Skid Resistance Evaluation on the Longterm Monitored Road Sections

    NASA Astrophysics Data System (ADS)

    Kotek, Peter; Kováč, Matúš; Decký, Martin

    2014-12-01

    The article deals with the analysis of the skid resistance results measured at the long-term monitored road sections in Slovakia in perspective of the possibility of the deterioration functions determination for the purposes of the pavement management system. There were 11 road sections evaluated, on which have been surface characteristics measured since 1998. The focus was on the evaluation of the longitudinal friction coefficient Mu measured by device Skiddometer BV11, which is the property of the Slovak Road Administration. Beside the Mu parameter, the test conditions were observed and evaluated, as well (measured speed, air and surface temperature, type of asphalts of the wearing course, traffic load, and the season (spring, autumn, respectively) in which the skid resistance measurements were performed. In conclusion, there was reviewed a presumption of the possibility to determine a deterioration functions for skid resistance in point of view the quality of the data, which have been collected on the Slovak long-term monitored road sections.

  19. Explosive Magnetic Reconnection in Double-current Sheet Systems: Ideal versus Resistive Tearing Mode

    NASA Astrophysics Data System (ADS)

    Baty, Hubert

    2017-03-01

    Magnetic reconnection associated with the tearing instability occurring in double-current sheet systems is investigated within the framework of resistive magnetohydrodynamics (MHD) in a two-dimensional Cartesian geometry. A special emphasis on the existence of fast and explosive phases is taken. First, we extend the recent theory on the ideal tearing mode of a single-current sheet to a double-current layer configuration. A linear stability analysis shows that, in long and thin systems with (length to shear layer thickness) aspect ratios scaling as {S}L9/29 (S L being the Lundquist number based on the length scale L), tearing modes can develop on a fast Alfvénic timescale in the asymptotic limit {S}L\\to ∞ . The linear results are confirmed by means of compressible resistive MHD simulations at relatively high S L values (up to 3× {10}6) for different current sheet separations. Moreover, the nonlinear evolution of the ideal double tearing mode (IDTM) exhibits a richer dynamical behavior than its single-tearing counterpart, as a nonlinear explosive growth violently ends up with a disruption when the two current layers interact trough the merging of plasmoids. The final outcome of the system is a relaxation toward a new state, free of magnetic field reversal. The IDTM dynamics is also compared to the resistive double tearing mode dynamics, which develops in similar systems with smaller aspect ratios, ≳ 2π , and exhibits an explosive secondary reconnection, following an initial slow resistive growth phase. Finally, our results are used to discuss the flaring activity in astrophysical magnetically dominated plasmas, with a particular emphasis on pulsar systems.

  20. Power flow analysis and optimal locations of resistive type superconducting fault current limiters.

    PubMed

    Zhang, Xiuchang; Ruiz, Harold S; Geng, Jianzhao; Shen, Boyang; Fu, Lin; Zhang, Heng; Coombs, Tim A

    2016-01-01

    Based on conventional approaches for the integration of resistive-type superconducting fault current limiters (SFCLs) on electric distribution networks, SFCL models largely rely on the insertion of a step or exponential resistance that is determined by a predefined quenching time. In this paper, we expand the scope of the aforementioned models by considering the actual behaviour of an SFCL in terms of the temperature dynamic power-law dependence between the electrical field and the current density, characteristic of high temperature superconductors. Our results are compared to the step-resistance models for the sake of discussion and clarity of the conclusions. Both SFCL models were integrated into a power system model built based on the UK power standard, to study the impact of these protection strategies on the performance of the overall electricity network. As a representative renewable energy source, a 90 MVA wind farm was considered for the simulations. Three fault conditions were simulated, and the figures for the fault current reduction predicted by both fault current limiting models have been compared in terms of multiple current measuring points and allocation strategies. Consequently, we have shown that the incorporation of the E-J characteristics and thermal properties of the superconductor at the simulation level of electric power systems, is crucial for estimations of reliability and determining the optimal locations of resistive type SFCLs in distributed power networks. Our results may help decision making by distribution network operators regarding investment and promotion of SFCL technologies, as it is possible to determine the maximum number of SFCLs necessary to protect against different fault conditions at multiple locations.

  1. Alfvén waves and current relaxation: attenuation at high frequencies and large resistivity

    NASA Astrophysics Data System (ADS)

    Silveira, F. E. M.

    2012-06-01

    The dispersion relations of Alfvén waves propagating in a resistive plasma are explored by assuming a finite relaxation time for the current density. It is shown that the proposed approach is consistent with the hydromagnetic approximation. An extension for the equation governing the space and time evolution of Alfvén waves is provided. New results are found at high values of the wave frequency ω: for a small resistivity, the wavelength increases as the cube of the equilibrium magnetic field but decreases with the cube of ω for a large resistivity, the wave attenuation does not depend on ω, saturating to a finite value which is fully determined by the relaxation time of the current density. A transition frequency, ωt, between two sharply distinct regimes of the perturbation is identified: for ω < ωt, the disturbance propagates in the resistive plasma as an attenuated oscillation; for ω > ωt the wave ceases very rapidly to oscillate (in space), its amplitude saturating to a finite value. The results presented here may be relevant for investigations of some transient phenomena in plasma physics such as the reconnection of magnetic field lines.

  2. Evaluating Support for the Current Classification of Eukaryotic Diversity

    PubMed Central

    Parfrey, Laura Wegener; Barbero, Erika; Lasser, Elyse; Dunthorn, Micah; Bhattacharya, Debashish; Patterson, David J; Katz, Laura A

    2006-01-01

    Perspectives on the classification of eukaryotic diversity have changed rapidly in recent years, as the four eukaryotic groups within the five-kingdom classification—plants, animals, fungi, and protists—have been transformed through numerous permutations into the current system of six “supergroups.” The intent of the supergroup classification system is to unite microbial and macroscopic eukaryotes based on phylogenetic inference. This supergroup approach is increasing in popularity in the literature and is appearing in introductory biology textbooks. We evaluate the stability and support for the current six-supergroup classification of eukaryotes based on molecular genealogies. We assess three aspects of each supergroup: (1) the stability of its taxonomy, (2) the support for monophyly (single evolutionary origin) in molecular analyses targeting a supergroup, and (3) the support for monophyly when a supergroup is included as an out-group in phylogenetic studies targeting other taxa. Our analysis demonstrates that supergroup taxonomies are unstable and that support for groups varies tremendously, indicating that the current classification scheme of eukaryotes is likely premature. We highlight several trends contributing to the instability and discuss the requirements for establishing robust clades within the eukaryotic tree of life. PMID:17194223

  3. Current Issues in Malignant Pleural Mesothelioma Evaluation and Management

    PubMed Central

    Ai, Jing

    2014-01-01

    Malignant pleural mesothelioma (MPM) is an uncommon disease most often associated with occupational asbestos exposure and is steadily increasing in worldwide incidence. Patients typically present at an older age, with advanced clinical stage and other medical comorbidities, making management quite challenging. Despite great efforts, the prognosis of MPM remains poor, especially at progression after initial treatment. Macroscopic complete resection of MPM can be achieved through extrapleural pneumonectomy (EPP) or extended (ie, radical) pleurectomy (e-P/D) in selected patients and can result in prolonged survival when incorporated into a multimodality approach. Given the morbidity associated with surgical resection of MPM, optimizing identification of appropriate patients is essential. Unfortunately, most patients are not candidates for EPP or e-P/D due to advanced stage, age, and/or medical comorbidity. Pemetrexed and platinum combination chemotherapy has become the cornerstone of therapy for patients with unresectable disease because the combination is associated with improved survival and quality of life in treated patients. However, MPM eventually becomes resistant to initial therapy, and benefit to further lines of therapy has not been substantiated in randomized clinical trials. Translational research has provided exciting insights into tumorigenesis, biomarkers, and immune response in MPM, leading to the development of multiple novel therapeutic agents that are currently in clinical trials. These advances hold the promise of a new era in the treatment of MPM and suggest that this disease will not be left behind in the war on cancer. PMID:25061089

  4. Effect of resistivity profile on current decay time of initial phase of current quench in neon-gas-puff inducing disruptions of JT-60U

    SciTech Connect

    Kawakami, S.; Ohno, N.; Shibata, Y.; Isayama, A.; Kawano, Y.; Watanabe, K. Y.; Takizuka, T.; Okamoto, M.

    2013-11-15

    According to an early work [Y. Shibata et al., Nucl. Fusion 50, 025015 (2010)] on the behavior of the plasma current decay in the JT-60U disruptive discharges caused by the radiative collapse with a massive neon-gas-puff, the increase of the internal inductance mainly determined the current decay time of plasma current during the initial phase of current quench. To investigate what determines the increase of the internal inductance, we focus attention on the relationship between the electron temperature (or the resistivity) profile and the time evolution of the current density profile and carry out numerical calculations. As a result, we find the reason of the increase of the internal inductance: The current density profile at the start of the current quench is broader than an expected current density profile in the steady state, which is determined by the temperature (or resistivity) profile. The current density profile evolves into peaked one and the internal inductance is increasing.

  5. The evaluation of corrosion resistant rod end rolling element bearings

    SciTech Connect

    Braza, J.F.; Giuntoli, K.; Imundo, J.R.

    1998-12-31

    Recent developments on carburizing grades of stainless steels have provided new materials to produce corrosion resistant airframe control bearings. This paper presents the application of one of these new carburizing grades of stainless steel to rod end ball bearings. The outer ring of the rod end bearing is made out of carburized stainless steel, while the inner ring and balls are made out of through-hardened stainless steel. The stainless steel rod end bearings were evaluated according to various ASTM and Military specifications for performance and corrosion resistance. The stainless steel rod end bearings exceeded the performance requirements of standard rod end bearings (which are comprised of a carburized 8620 steel outer ring and 52100 steel inner ring and balls) in accordance with MIL-B-6039. The rod end bearings were evaluated in the radial fracture load, axial fracture load, and radial dynamic load tests. Also, salt spray and alternate immersion corrosion tests (ASTM B 117-85 and G 44-88, respectively) were conducted on the stainless steel rod end bearings. The stainless steel rod end bearings exhibited superior corrosion resistance to the standard 8620/52100 steel rod end bearings.

  6. Current imaging strategies for the evaluation of uterine cervical cancer

    PubMed Central

    Bourgioti, Charis; Chatoupis, Konstantinos; Moulopoulos, Lia Angela

    2016-01-01

    Uterine cervical cancer still remains an important socioeconomic issue because it largely affects women of reproductive age. Prognosis is highly depended on extent of the disease at diagnosis and, therefore, accurate staging is crucial for optimal management. Cervical cancer is clinically staged, according to International Federation of Gynecology and Obstetrics guidelines, but, currently, there is increased use of cross sectional imaging modalities [computed tomography (CT), magnetic resonance imaging (MRI), positron emission tomography-CT (PET-CT)] for the study of important prognostic factors like tumor size, parametrial invasion, endocervical extension, pelvic side wall or adjacent/distal organs involvement and lymph node status. Imaging indications also include cervical cancer follow-up, evaluation of tumor response to treatment and selection of suitable candidates for less radical surgeries like radical trachelectomy for fertility preservation. The preferred imaging method for local cervical cancer evaluation is MRI; CT is equally effective for evaluation of extrauterine spread of the disease. PET-CT shows high diagnostic performance for the detection of tumor relapse and metastatic lymph nodes. The aim of this review is to familiarize radiologists with the MRI appearance of cervical carcinoma and to discuss the indications of cross sectional imaging during the course of the disease in patients with cervical carcinoma. PMID:27158421

  7. Laboratory Observation of Resistive Electron Tearing in a Two-Fluid Reconnecting Current Sheet

    NASA Astrophysics Data System (ADS)

    Jara-Almonte, Jonathan; Ji, Hantao; Yamada, Masaaki; Yoo, Jongsoo; Fox, William

    2016-08-01

    The spontaneous formation of plasmoids via the resistive electron tearing of a reconnecting current sheet is observed in the laboratory. These experiments are performed during driven, antiparallel reconnection in the two-fluid regime within the Magnetic Reconnection Experiment. It is found that plasmoids are present even at a very low Lundquist number, and the number of plasmoids scales with both the current sheet aspect ratio and the Lundquist number. The reconnection electric field increases when plasmoids are formed, leading to an enhanced reconnection rate.

  8. Laboratory observation of resistive electron tearing in a two-fluid reconnecting current sheet

    SciTech Connect

    Jara-Almonte, Jonathan; Ji, Hantao; Yamada, Masaaki; Yoo, Jongsoo; Fox, William

    2016-08-25

    The spontaneous formation of plasmoids via the resistive electron tearing of a reconnecting current sheet is observed in the laboratory. These experiments are performed during driven, antiparallel reconnection in the two-fluid regime within the Magnetic Reconnection Experiment. It is found that plasmoids are present even at a very low Lundquist number, and the number of plasmoids scales with both the current sheet aspect ratio and the Lundquist number. Furthermore, the reconnection electric field increases when plasmoids are formed, leading to an enhanced reconnection rate.

  9. Investigation of Thickness and Electrical Resistivity of the Current Sheets in Solar Eruptions

    NASA Technical Reports Server (NTRS)

    Lin, J.; Li, J.; Ko, Y.-K.; Raymond, J. C.

    2009-01-01

    A discussion of the thickness of current sheets in solar eruptions led Lin et al. in 2007 to estimate very large values for the effective resistivity. This paper addresses some questions raised by that paper. The limb synoptic map technique is applied to find the current sheet thickness to be between 5.OE4 and 4.6E5 km, increasing with both time and altitude. The possibility that large apparent values result from projection effects is examined and rejected. Theoretical scaling laws corroborate this conclusion.

  10. Thermal-resistive current filamentation in the cathode plasma of a pinch-reflex diode

    SciTech Connect

    Tripathi, V.K.; Ottinger, P.F.; Guillory, J.

    1983-06-01

    Electron current flow drawn off a hollow cylindrical cathode in a pinch-reflex ion diode is observed to have a filamentary structure. Such filamentation can lead to nonuniform anode turn on and ion emission. Consequently, ion beam brightness is degraded. In this context a purely growing thermal-resistive instability in the cathode plasma is examined. The instability causes current filamentation and grows on a time scale comparable to the electron--ion energy equilibration time. Electron inelastic collisions have a stabilizing influence on the instability.

  11. Spontaneous dc Current Generation in a Resistively Shunted Semiconductor Superlattice Driven by a Terahertz Field

    SciTech Connect

    Alekseev, K.N.; Cannon, E.H.; McKinney, J.C.; Campbell, D.K.; Alekseev, K.N.; Kusmartsev, F.V.; Alekseev, K.N.; Kusmartsev, F.V.

    1998-03-01

    We study a resistively shunted semiconductor superlattice subject to a high-frequency electric field. Using a balance equation approach that incorporates the influence of the electric circuit, we determine numerically a range of amplitude and frequency of the ac field for which a dc bias and current are generated {ital spontaneously} and show that this region is likely accessible to current experiments. Our simulations reveal that the Bloch frequency corresponding to the spontaneous dc bias is approximately an integer multiple of the ac field frequency. {copyright} {ital 1998} {ital The American Physical Society}

  12. Method and apparatus for remote tube crevice detection by current and voltage probe resistance measurement

    DOEpatents

    Kikta, T.J.; Mitchell, R.D.

    1992-11-24

    A method and apparatus for determining the extent of contact between an electrically conducting tube and an electrically conductive tubesheet surrounding the tube, based upon the electrical resistance of the tube and tubesheet. A constant current source is applied to the interior of the electrically conducting tube by probes and a voltmeter is connected between other probes to measure the voltage at the point of current injection, which is inversely proportional to the amount of contact between the tube and tubesheet. Namely, the higher the voltage measured by the voltmeter, the less contact between the tube and tubesheet. 4 figs.

  13. Method and apparatus for remote tube crevice detection by current and voltage probe resistance measurement

    DOEpatents

    Kikta, Thomas J.; Mitchell, Ronald D.

    1992-01-01

    A method and apparatus for determining the extent of contact between an electrically conducting tube and an electrically conductive tubesheet surrounding the tube, based upon the electrical resistance of the tube and tubesheet. A constant current source is applied to the interior of the electrically conducting tube by probes and a voltmeter is connected between other probes to measure the voltage at the point of current injection, which is inversely proportional to the amount of contact between the tube and tubesheet. Namely, the higher the voltage measured by the voltmeter, the less contact between the tube and tubesheet.

  14. Laboratory Observation of Resistive Electron Tearing in a Two-Fluid Reconnecting Current Sheet.

    PubMed

    Jara-Almonte, Jonathan; Ji, Hantao; Yamada, Masaaki; Yoo, Jongsoo; Fox, William

    2016-08-26

    The spontaneous formation of plasmoids via the resistive electron tearing of a reconnecting current sheet is observed in the laboratory. These experiments are performed during driven, antiparallel reconnection in the two-fluid regime within the Magnetic Reconnection Experiment. It is found that plasmoids are present even at a very low Lundquist number, and the number of plasmoids scales with both the current sheet aspect ratio and the Lundquist number. The reconnection electric field increases when plasmoids are formed, leading to an enhanced reconnection rate.

  15. Evaluation of microelectrode materials for direct-current electrocorticography

    NASA Astrophysics Data System (ADS)

    Li, Chunyan; Narayan, Raj K.; Wu, Pei-Ming; Rajan, Neena; Wu, Zhizhen; Mehan, Neal; Golanov, Eugene V.; Ahn, Chong H.; Hartings, Jed A.

    2016-02-01

    Objective. Direct-current electrocorticography (DC-ECoG) allows a more complete characterization of brain states and pathologies than traditional alternating-current recordings (AC-ECoG). However, reliable recording of DC signals is challenging because of electrode polarization-induced potential drift, particularly at low frequencies and for more conducting materials. Further challenges arise as electrode size decreases, since impedance is increased and the potential drift is augmented. While microelectrodes have been investigated for AC-ECoG recordings, little work has addressed microelectrode properties for DC-signal recording. In this paper, we investigated several common microelectrode materials used in biomedical application for DC-ECoG. Approach. Five of the most common materials including gold (Au), silver/silver chloride (Ag/AgCl), platinum (Pt), Iridium oxide (IrOx), and platinum-iridium oxide (Pt/IrOx) were investigated for electrode diameters of 300 μm. The critical characteristics such as polarization impedance, AC current-induced polarization, long-term stability and low-frequency noise were studied in vitro (0.9% saline). The two most promising materials, Pt and Pt/lrOx were further investigated in vivo by recording waves of spreading depolarization, one of the most important applications for DC-ECoG in clinical and basic science research. Main results. Our experimental results indicate that IrOx-based microelectrodes, particularly with composite layers of nanostructures, are excellent in all of the common evaluation characteristics both in vitro and in vivo and are most suitable for multimodal monitoring applications. Pt electrodes suffer high current-induced polarization, but have acceptable long-term stability suitable for DC-ECoG. Major significance. The results of this study provide quantitative data on the electrical properties of microelectrodes with commonly-used materials and will be valuable for development of neural recordings inclusive of

  16. Evaluation of Chromogenic Media in Detection of Vancomycin Resistant Enterococci

    PubMed Central

    S., Vijaya; S.T., Santhya; M.K., Yashaswini; S., Megha

    2014-01-01

    Introduction: Vancomycin resistant Enterococci have become important nosocomial pathogens. So it is necessary to monitor continuously such infections in the hospitals. Materials and Methods: A total of 100 Enterococci isolated from 4489 various clinical samples were speciated and antibiogram was done according to standard laboratory methods. The efficacy of CHROMagarTM VRE (France) and Hicrome VRE (Himedia) in detecting VRE was evaluated using E- test (Himedia). Results: Hicrome VRE and CHROMagarTM VRE showed sensitivity of 100% and specificity of 99% as compared to E-test. Conclusion: In the present study VRE was not isolated. Prudent use of vancomycin and continuous surveillance for VRE will prevent the emergence of vancomycin resistant Enterococci in the locality in future. Identification of VRE by chromogenic media is rapid, easy to perform, cost effective compared to technically demanding, time consuming and costly conventional method. PMID:25584221

  17. Analytical evaluations of coupling impedances of resistive and magnetic bellows

    NASA Astrophysics Data System (ADS)

    Shobuda, Yoshihiro

    2014-03-01

    A theory is developed to calculate both the longitudinal and transverse impedances of magnetic as well as resistive bellows with cylindrical symmetry that is sandwiched between chambers with perfectly conductive metal fittings. Analytical estimations of the impedances are necessary because the skin depth is too small to make sufficiently tiny mesh sizes in current numerical codes. The impedances of bellows made of materials having both large conductivity and permeability are drastically increased owing to magnetic effects, compared with those of bellows made of perfectly conductive materials.

  18. Gas turbine coatings eddy current quantitative and qualitative evaluation

    NASA Astrophysics Data System (ADS)

    Ribichini, Remo; Giolli, Carlo; Scrinzi, Erica

    2017-02-01

    Gas turbine blades (buckets) are among the most critical and expensive components of the engine. Buckets rely on protective coatings in order to withstand the harsh environment in which they operate. The thickness and the microstructure of coatings during the lifespan of a unit are fundamental to evaluate their fitness for service. A frequency scanning Eddy Current instrument can allow the measurement of the thickness and of physical properties of coatings in a Non-Destructive manner. The method employed relies on the acquisition of impedance spectra and on the inversion of the experimental data to derive the coating properties and structure using some assumptions. This article describes the experimental validation performed on several samples and real components in order to assess the performance of the instrument as a coating thickness gage. The application of the technique to support residual life assessment of serviced buckets is also presented.

  19. Evaluation of Current Planetary Boundary Layer Retrieval Capabilities from Space

    NASA Technical Reports Server (NTRS)

    Santanello, Joseph A., Jr.; Schaefer, Alexander J.; Blaisdell, John; Yorks, John

    2016-01-01

    The PBL over land remains a significant gap in our water and energy cycle understanding from space. This work combines unique NASA satellite and model products to demonstrate the ability of current sensors (advanced IR sounding and lidar) to retrieve PBL properties and in turn their potential to be used globally to evaluate and improve weather and climate prediction models. While incremental progress has been made in recent AIRS retrieval versions, insufficient vertical resolution remains in terms of detecting PBL properties. Lidar shows promise in terms of detecting vertical gradients (and PBLh) in the lower troposphere, but daytime conditions over land remain a challenge due to noise, and their coverage is limited to approximately 2 weeks or longer return times.

  20. Monitoring and adaptive resistance management in Australia for Bt-cotton: current status and future challenges.

    PubMed

    Downes, Sharon; Mahon, Rod; Olsen, Karen

    2007-07-01

    In the mid-1990 s the Australian Cotton industry adopted an insect-resistant variety of cotton (Ingard) which expresses the Bt toxin Cry1Ac that is specific to a group of insects including the target Helicoverpa armigera. A conservative resistance management plan (RMP), that restricted the area planted to Ingard, was implemented to preserve the efficacy of Cry1Ac until two-gene transgenic cotton was available. In 2004/05 Bollgard II replaced Ingard as the transgenic cotton available in Australia. It improves on Ingard by incorporating an additional insecticidal protein (Cry2Ab). If an appropriate refuge is grown, there is no restriction on the area planted to Bollgard II. In 2004/05 and 2005/06 the Bollgard II acreage represented approximately 80 of the total area planted to cotton in Australia. The sensitivity of field-collected populations of H. armigera to Bt products was assayed before and subsequent to the widespread deployment of Ingard cotton. In 2002 screens against Cry2Ab were developed in preparation for replacement of Ingard with Bollgard II. There have been no reported field failures of Bollgard II due to resistance. However, while alleles that confer resistance to H. armigera in the field are rare for Cry1Ac, they are surprisingly common for Cry2Ab. We present an overview of the current approach adopted in Australia to monitor and adaptively manage resistance to Bt-cotton in field populations of H. armigera and discuss the implications of our findings to date. We also highlight future challenges for resistance management in Australia, many of which extend to other Bt-crop and pest systems.

  1. Evaluation of dual flow counter-current chromatography and intermittent counter-current extraction.

    PubMed

    Ignatova, Svetlana; Hewitson, Peter; Mathews, Ben; Sutherland, Ian

    2011-09-09

    The aim of this research is to compare two continuous extraction technologies, intermittent counter-current extraction (ICcE) and dual flow counter-current chromatography (DFCCC), in terms of loading and throughput using the GUESSmix, and show the advantages and disadvantages of the two methods. A model sample containing caffeine, vanillin, naringenin and carvone, with a total load of 11.2 g, was employed with a hexane-ethyl acetate-methanol-water (2:3:2:3) phase system to evaluate an ICcE method on a preparative (912 ml coil volume) DE-Midi instrument. While DFCCC was carried out on a specially designed preparative (561 ml coil volume) bobbin installed in a similar Midi instrument case. While similar throughputs of 7.8 g/h and 6.9 g/h were achieved for the ICcE and DFCCC methods respectively, ICcE was demonstrated to have a number of advantages over DFCCC.

  2. Focused subsurface flow in the Amargosa Desert characterized by direct-current resistivity profiling

    NASA Astrophysics Data System (ADS)

    Stonestrom, D. A.; Abraham, J. D.; Lucius, J. E.; Prudic, D. E.

    2003-12-01

    Environmental-tracer studies have shown that ground-water recharge in the thick alluvial fill of the Amargosa Desert is localized beneath ephemeral stream channels and anthropogenic sources of water, with little recharge beneath native vegetation on interfluvial areas under current climatic conditions. These borehole-based studies provided relatively robust but limited, one-dimensional (vertical) information that can be only tentatively regionalized using geomorphologic, pedologic, and vegetational mapping. The ability of direct-current (DC) resistivity profiling to complement and extend studies of the spatial distribution of subsurface flow was examined by making surface-based measurements ("soundings") along one transect normal to the depositional fabric in each of three geomorphologically distinct settings: a well-incised ephemeral channel system, a poorly incised (distributory) ephemeral channel system, and an interfluvial upland. Linear arrays of 32 to 80 electrodes were deployed with a uniform 2 to 5-m spacing between adjacent electrodes. A multiplexing 8-channel resistivity instrument made automated inverse-Schlumberger-array soundings along the deployed line, using up to 10 electrodes at a time. The line was shifted piecemeal until composite transects consisted of 168 to 232 electrode positions. This approach allowed rapid profiling of long transects at high resolution. Numerical inversions assumed horizontal constancy normal to the vertical slices being imaged, producing solution sets of optimized resistivity values for several thousand points within each modeled slice. Imaged slices were ˜30 to 80 m deep and ˜1 km wide. RMS errors between apparent resistivities in the model inversions and field-measured apparent resistivities were ˜10%. On the basis of borehole studies, inverted resistivity (ρ ) values denoted three categories of alluvium: (1) low-water-content coarse gravel and highly desiccated surface materials, with ρ > ˜200 Ω -m, (2) vertical

  3. Proliferation Resistance Evaluation of ACR-1000 Fuel with Minor Actinides

    SciTech Connect

    Gray S. Chang

    2008-09-01

    The Global Nuclear Energy Partnership (GNEP) program is to significantly advance the science and technology of nuclear energy systems and to enhance the spent fuel proliferation resistance. It consists of both innovative nuclear reactors and innovative research in separation and transmutation. The merits of nuclear energy are high-density energy, with low environmental impacts (i.e. almost zero greenhouse gas emission). Planned efforts involve near-term and intermediate-term improvements in fuel utilization and recycling in current light water reactors (LWRs) as well as the longer-term development of new nuclear energy systems that offer much improved fuel utilization and proliferation resistance, along with continued advances in operational safety. For future advanced nuclear systems, minor actinides (MA) are viewed more as a resource to be recycled, and transmuted to less hazardous and possibly more useful forms, rather than simply disposed of as a waste stream in an expensive repository facility. MAs can play a much larger part in the design of advanced systems and fuel cycles, not only as additional sources of useful energy, but also as direct contributors to the reactivity control of the systems into which they are incorporated. In this work, an Advanced CANDU Reactor (ACR) fuel unit lattice cell model with 43 UO2 fuel rods will be used to investigate the effectiveness of a Minor Actinide Reduction Approach (MARA) for enhancing proliferation resistance and improving the fuel cycle performance. The main MARA objective is to increase the 238Pu / Pu isotope ratio by using the transuranic nuclides (237Np and 241Am) in the high burnup fuel and thereby increase the proliferation resistance even for a very low fuel burnup. As a result, MARA is a very effective approach to enhance the proliferation resistance for the on power refueling ACR system nuclear fuel. The MA transmutation characteristics at different MA loadings were compared and their impact on neutronics

  4. Calculating electron cyclotron current drive stabilization of resistive tearing modes in a nonlinear magnetohydrodynamic model

    SciTech Connect

    Jenkins, Thomas G.; Schnack, Dalton D.; Kruger, Scott E.; Hegna, C. C.; Sovinec, Carl R.

    2010-01-15

    A model which incorporates the effects of electron cyclotron current drive (ECCD) into the magnetohydrodynamic equations is implemented in the NIMROD code [C. R. Sovinec et al., J. Comput. Phys. 195, 355 (2004)] and used to investigate the effect of ECCD injection on the stability, growth, and dynamical behavior of magnetic islands associated with resistive tearing modes. In addition to qualitatively and quantitatively agreeing with numerical results obtained from the inclusion of localized ECCD deposition in static equilibrium solvers [A. Pletzer and F. W. Perkins, Phys. Plasmas 6, 1589 (1999)], predictions from the model further elaborate the role which rational surface motion plays in these results. The complete suppression of the (2,1) resistive tearing mode by ECCD is demonstrated and the relevant stabilization mechanism is determined. Consequences of the shifting of the mode rational surface in response to the injected current are explored, and the characteristic short-time responses of resistive tearing modes to spatial ECCD alignments which are stabilizing are also noted. We discuss the relevance of this work to the development of more comprehensive predictive models for ECCD-based mitigation and control of neoclassical tearing modes.

  5. Calculating electron cyclotron current drive stabilization of resistive tearing modes in a nonlinear magnetohydrodynamic model

    NASA Astrophysics Data System (ADS)

    Jenkins, Thomas G.; Kruger, Scott E.; Hegna, C. C.; Schnack, Dalton D.; Sovinec, Carl R.

    2010-01-01

    A model which incorporates the effects of electron cyclotron current drive (ECCD) into the magnetohydrodynamic equations is implemented in the NIMROD code [C. R. Sovinec et al., J. Comput. Phys. 195, 355 (2004)] and used to investigate the effect of ECCD injection on the stability, growth, and dynamical behavior of magnetic islands associated with resistive tearing modes. In addition to qualitatively and quantitatively agreeing with numerical results obtained from the inclusion of localized ECCD deposition in static equilibrium solvers [A. Pletzer and F. W. Perkins, Phys. Plasmas 6, 1589 (1999)], predictions from the model further elaborate the role which rational surface motion plays in these results. The complete suppression of the (2,1) resistive tearing mode by ECCD is demonstrated and the relevant stabilization mechanism is determined. Consequences of the shifting of the mode rational surface in response to the injected current are explored, and the characteristic short-time responses of resistive tearing modes to spatial ECCD alignments which are stabilizing are also noted. We discuss the relevance of this work to the development of more comprehensive predictive models for ECCD-based mitigation and control of neoclassical tearing modes.

  6. Evaluation of a variable resistance orthotic knee joint.

    PubMed

    Herbert-Copley, Andrew; Lemaire, Edward D; Baddour, Natalie

    2016-08-01

    Knee-ankle-foot orthoses (KAFOs) are full leg braces for individuals with knee extensor weakness, designed to support the person during weight bearing activities by preventing knee flexion. KAFOs typically result in an unnatural gait pattern and are primarily used for level ground walking. A novel variable resistance orthotic knee joint, the Ottawalk-Variable Speed (OWVS), was designed to address these limitations. This paper presents a pilot test to evaluate the OWVS functional performance during walking and stair descent. A carbon-fiber KAFO was adjusted for an able-bodied participant by a certified orthotist, with a standard orthotic single axis knee joint on the medial side and the OWVS on the lateral side. The participant performed level ground walking (stance-control, open, closed) and stair descent tests. The operator was able to manually switch between closed mode in terminal swing to open mode in terminal stance for stance-control walking. Knee angle kinematics were similar between open and stance control modes. For stair descent, resistance settings supported the participant as they lowered their body to the next step, but with smaller range of motion compared to the open setting. The Ottawalk-Variable Speed design successfully controls knee flexion during stance and stair descent, with one lateral control joint. Mode switching was fast and appropriate. This microprocessor controlled SCKAFO has a low profile that fits beneath clothing and the variable resistance design will allow people to negotiate different terrain types.

  7. Prospective evaluation of ResistancePlus™ MG, a new multiplex qPCR assay for the detection of Mycoplasma genitalium and macrolide resistance.

    PubMed

    Tabrizi, S N; Su, J; Bradshaw, C S; Fairley, C K; Walker, S; Tan, L Y; Mokany, E; Garland, S M

    2017-04-05

    Mycoplasma genitalium is a significant pathogen for which first-line treatment is becoming less effective due to increased resistance to macrolides. As conventional culture and antimicrobial susceptibility testing is not feasible for routine detection of this pathogen, molecular markers such as detection of mutations in the 23S rRNA gene have been described to predict resistance. Recently a novel multiplex qPCR assay, ResistancePlus™ MG, has been described for the simultaneous detection of Mycoplasma genitalium and macrolide resistance. In the current study, the clinical performance of the assay was evaluated on 1089 consecutive urine and anogenital swab samples in symptomatic and asymptomatic male and female patients. Overall, 6.0% were positive for M. genitalium, with 63.1% having macrolide resistance associated mutations. When compared to the laboratory validated qPCR method targeting the 16S rRNA gene and Sanger sequencing to determine 23S rRNA mutations, sensitivity/specificity of M. genitalium detection was 98.5%/100%, and for detection of macrolide resistance mutation was 100.0%/96.2%, respectively. This assay offers a considerable advantage in clinical settings for M. genitalium testing by making the results of macrolide resistance mutation simultaneously available, which is increasingly important with escalating macrolide resistance.

  8. Current methodologies on genotyping for nosocomial pathogen methicillin-resistant Staphylococcus aureus (MRSA).

    PubMed

    Miao, Jian; Chen, Lequn; Wang, Jingwen; Wang, Wenxin; Chen, Dingqiang; Li, Lin; Li, Bing; Deng, Yang; Xu, Zhenbo

    2017-03-08

    Methicillin-resistant Staphylococcus aureus (MRSA) is a common pathogen in hospitals and the community. As the rapid spread and wide distribution of antimicrobial resistance (such as MRSA), treatment for infectious diseases caused by microorganisms has become a vital threat. Thus, early identification and genotyping are essential for further therapeutic treatment and the control of rapid expansion of MRSA. In combination with applications and data feedbacks, this review focused on the currently available molecular-based assays on their utility and performance for rapid typing of MRSA, especially on effective molecular-based methods. Besides, a common mobile element SCCmec and prevalence of HA-MRSA, LA-MRSA and CA-MRSA were introduced in this review in order to provide a more complete profile of MRSA.

  9. Current understanding of iberiotoxin-resistant BK channels in the nervous system

    PubMed Central

    Wang, Bin; Jaffe, David B.; Brenner, Robert

    2014-01-01

    While most large-conductance, calcium-, and voltage-activated potassium channels (BK or Maxi-K type) are blocked by the scorpion venom iberiotoxin, the so-called “type II” subtype has the property of toxin resistance. This property is uniquely mediated by channel assembly with one member of the BK accessory β subunit family, the neuron-enriched β4 subunit. This review will focus on current understanding of iberiotoxin-resistant, β4-containing BK channel properties and their function in the CNS. Studies have shown that β4 dramatically promotes BK channel opening by shifting voltage sensor activation to more negative voltage ranges, but also slows activation to timescales that theoretically preclude BK ability to shape action potentials (APs). In addition, β4 membrane trafficking is regulated through an endoplasmic retention signal and palmitoylation. More recently, the challenge has been to understand the functional role of the iberiotoxin-resistant BK subtype utilizing computational modeling of neurons and neurophysiological approaches. Utilizing iberiotoxin-resistance as a footprint for these channels, they have been identified in dentate gyrus granule neurons and in purkinje neurons of the cerebellum. In these neurons, the role of these channels is largely consistent with slow-gated channels that reduce excitability either through an interspike conductance, such as in purkinje neurons, or by replacing fast-gating BK channels that otherwise facilitate high frequency AP firing, such as in dentate gyrus neurons. They are also observed in presynaptic mossy fiber terminals of the dentate gyrus and posterior pituitary terminals. More recent studies suggest that β4 subunits may also be expressed in some neurons lacking iberiotoxin-resistant BK channels, such as in CA3 hippocampus neurons. Ongoing research using novel, specific blockers and agonists of BK/β4, and β4 knockout mice, will continue to move the field forward in understanding the function of these

  10. Current understanding of iberiotoxin-resistant BK channels in the nervous system.

    PubMed

    Wang, Bin; Jaffe, David B; Brenner, Robert

    2014-01-01

    While most large-conductance, calcium-, and voltage-activated potassium channels (BK or Maxi-K type) are blocked by the scorpion venom iberiotoxin, the so-called "type II" subtype has the property of toxin resistance. This property is uniquely mediated by channel assembly with one member of the BK accessory β subunit family, the neuron-enriched β4 subunit. This review will focus on current understanding of iberiotoxin-resistant, β4-containing BK channel properties and their function in the CNS. Studies have shown that β4 dramatically promotes BK channel opening by shifting voltage sensor activation to more negative voltage ranges, but also slows activation to timescales that theoretically preclude BK ability to shape action potentials (APs). In addition, β4 membrane trafficking is regulated through an endoplasmic retention signal and palmitoylation. More recently, the challenge has been to understand the functional role of the iberiotoxin-resistant BK subtype utilizing computational modeling of neurons and neurophysiological approaches. Utilizing iberiotoxin-resistance as a footprint for these channels, they have been identified in dentate gyrus granule neurons and in purkinje neurons of the cerebellum. In these neurons, the role of these channels is largely consistent with slow-gated channels that reduce excitability either through an interspike conductance, such as in purkinje neurons, or by replacing fast-gating BK channels that otherwise facilitate high frequency AP firing, such as in dentate gyrus neurons. They are also observed in presynaptic mossy fiber terminals of the dentate gyrus and posterior pituitary terminals. More recent studies suggest that β4 subunits may also be expressed in some neurons lacking iberiotoxin-resistant BK channels, such as in CA3 hippocampus neurons. Ongoing research using novel, specific blockers and agonists of BK/β4, and β4 knockout mice, will continue to move the field forward in understanding the function of these

  11. Current Trends, Evaluation, and Management of Pediatric Nephrolithiasis.

    PubMed

    Hernandez, Joel D; Ellison, Jonathan S; Lendvay, Thomas S

    2015-10-01

    The incidence of pediatric nephrolithiasis has been steadily increasing for the past several decades, with a concomitant concerning increase in health care costs and burden to children with this disease. Recent population-based studies have also demonstrated a change in the current trends of pediatric nephrolithiasis that is characterized by a significant increase in the number of girls now being affected. While changes in diet and lifestyle, obesity prevalence, and even imaging practices have been proposed to contribute to the recent increase in pediatric nephrolithiasis, a definite underlying cause remains elusive. This situation is complicated by the fact that, unlike in adults, the trends occurring in pediatric nephrolithiasis have not been studied rigorously, which contributes to the paucity of data in children. The level of concern with the increasing incidence is raised by factors unique to pediatric nephrolithiasis that could expose an affected child to more complications. Factors such as variable clinical presentation, high recurrence of kidney stones associated with abnormalities of metabolism and the urinary tract, and the possible presence of rare genetic kidney stone diseases would require physicians to comprehensively evaluate patients presenting with kidney stones. The goal of evaluation is to identify modifiable risk factors and abnormalities for which targeted therapy can be prescribed. The goals of medical and surgical treatments are to eliminate the burden of kidney stones and prevent recurrence while simultaneously minimizing complications from interventions. Patients at high risk may benefit from a specialized kidney stone clinic staffed by a pediatric nephrologist, urologist, dietitian, and clinical nurse. Such a multidisciplinary clinic can help provide the medical and surgical support needed for patients at high risk and offer key opportunities to learn more about pediatric nephrolithiasis, thereby fueling the much-needed research in this

  12. Experimental Demonstration of Resistive Electron Plasmoids in a Reconnecting Current Sheet

    NASA Astrophysics Data System (ADS)

    Jara-Almonte, Jonathan

    2016-10-01

    Magnetic reconnection is an important process occurring in nearly all magnetized plasmas that involves the complex coupling of multiple physical scales. Significant progress has been made in understanding the cross-scale physics of magnetic reconnection around localized reconnection sites, but how reconnection couples to global physics is still an open question. Recently, the spontaneous formation of plasmoids has been proposed as a mechanism for bridging widely disparate scales, thereby permitting fast reconnection in large systems. Numerous works have demonstrated the existence of collisionless plasmoids in both space and laboratory plasmas, however to-date, direct evidence for collisional plasmoids has been confined to numerical simulations and analytic theory, although remote-sensing observations of solar and fusion plasmas have provided some indirect evidence. However, it is known that many naturally occurring plasmas, such as the solar chromosphere or the interstellar medium, are both large and collisional, thus requiring collisional plasmoids. In part, the current lack of experimental or in situ observational evidence for collisional plasmoids is due to the large Lundquist numbers required for plasmoid formation within the resistive MHD framework. In this work, experimental evidence for resistive electron plasmoid formation during magnetic reconnection in the two-fluid regime is given. Using the Magnetic Reconnection Experiment (MRX), driven reconnection is studied in collisional current sheets wherein the electric field is balanced solely by classical Spitzer resistivity. Despite low Lundquist numbers, these collisional current sheets are observed to be unstable to the spontaneous formation of plasmoids, which is explained by the importance of electron physics when in the two-fluid regime. The number of plasmoids is observed to scale with the Lundquist number. Due to the onset of plasmoids, both the local reconnection electric field and the globally

  13. Effect of parasitic series resistances and spurious currents on the extracted temperature of a bipolar junction transistor.

    PubMed

    Mimila-Arroyo, J

    2013-12-01

    Verster's proposition to directly extract the temperature of a bipolar junction transistor using its collector current is widely used. However, the resulting temperature is low accurate even when calibrated. Here, it is demonstrated that the misuse of the emitter current instead of the collector one, because of the presence of spurious currents other than the injection-diffusion one and transistor parasitic series resistances both contribute to the observed inaccuracy. Particularly parasitic series resistances increase the inaccuracy and introduce a strong dependence of the extracted temperature on the collector currents used to extract the temperature; the higher those resistances the higher the inaccuracy. A proposition is made to reduce the effect of those resistances on the inaccuracy of this thermometric element, which allows obtaining a more accurate value on a wider range of the collector probe currents.

  14. Targeted treatment of recurrent platinum-resistant ovarian cancer: current and emerging therapies

    PubMed Central

    Mantia-Smaldone, Gina M; Edwards, Robert P; Vlad, Anda M

    2010-01-01

    With advances in surgical techniques and chemotherapeutic agents, mortality rates from epithelial ovarian cancer (EOC) have slightly decreased over the last 30 years. However, EOC still ranks as the most deadly gynecologic cancer with an overall 5-year survival rate of 45%. Prognosis is especially disappointing for women with platinum-resistant disease, where 80% of patients will fail to respond to available therapies. Emerging treatment strategies have sub-sequently focused on targets which are integral to tumor growth and metastasis. In this review, we will focus on those innovative agents currently under investigation in clinical trials. PMID:21734812

  15. New in vitro tests to evaluate the resistance level of the cattle tick, Rhipicephalus (Boophilus) microplus, against acaricides

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of the present study was to compare two new in vitro tests designed to evaluate the resistance level of R. microplus with two tests currently recommended by the Food and Agriculture Organization of the United Nations (FAO): one performed on larvae, the Larval Packet Test (LPT) and one ...

  16. Religious slaughter: evaluation of current practices in selected countries.

    PubMed

    Velarde, A; Rodriguez, P; Dalmau, A; Fuentes, C; Llonch, P; von Holleben, K V; Anil, M H; Lambooij, J B; Pleiter, H; Yesildere, T; Cenci-Goga, B T

    2014-01-01

    As part of the project "Religious slaughter (DIALREL): improving knowledge and expertise through dialogue and debate on issues of welfare, legislation and socio-economic aspects", this paper discusses an evaluation of current practices during Halal and Shechita slaughter in cattle, sheep, goats and poultry. During religious slaughter, animals are killed with and without stunning by a transverse incision across the neck that is cutting the skin, muscles (brachiocephalic, sternocephalic, sternohyoid, and sternothyroid), trachea, esophagus, carotid arteries, jugular veins and the major, superficial and deep nerves of the cervical plexus. In this report, the restraint methods, stunning, neck cutting, exsanguination, slaughter techniques and postcut handling in the abattoir were assessed for religious slaughter. Information about the procedures used during religious slaughter in Belgium, Germany, Italy, the Netherlands, Spain, the UK, Turkey and Australia was collected by means of spot visits to abattoirs. To standardize the information gathered during the spot visits three guidelines were designed, one for each species, and translated into the national languages of the countries involved. The document included questions on the handling and restraint methods (stunning, neck cutting/exsanguination/slaughter techniques and postcut handling performed under religious practices) and for pain and distress of the animal during the restraint, neck cutting and induction to death in each abattoir. Results showed differences in the time from restraining to stun and to cut in the neck cutting procedures and in the time from cut to death.

  17. Evaluation of EUV resist performance using interference lithography

    NASA Astrophysics Data System (ADS)

    Buitrago, E.; Yildirim, O.; Verspaget, C.; Tsugama, N.; Hoefnagels, R.; Rispens, G.; Ekinci, Y.

    2015-03-01

    Extreme ultraviolet lithography (EUVL) stands as the most promising solution for the fabrication of future technology nodes in the semiconductor industry. Nonetheless, the successful introduction of EUVL into the extremely competitive and stringent high-volume manufacturing (HVM) phase remains uncertain partly because of the still limiting performance of EUV resists below 16 nm half-pitch (HP) resolution. Particularly, there exists a trade-off relationship between resolution (half-pitch), sensitivity (dose) and line-edge roughness (LER) that can be achieved with existing materials. This trade-off ultimately hampers their performance and extendibility towards future technology nodes. Here we present a comparative study of highly promising chemically amplified resists (CARs) that have been evaluated using the EUV interference lithography (EUV-IL) tool at the Swiss Light Source (SLS) synchrotron facility in the Paul Scherrer Institute (PSI). In this study we have focused on the performance qualification of different resists mainly for 18 nm and 16 nm half-pitch line/space resolution (L/S = 1:1). Among the most promising candidates tested, there are a few choices that allow for 16 nm HP resolution to be achieved with high exposure latitude (up to ~ 33%), low LER (down to 3.3 nm or ~ 20% of critical dimension CD) and low dose-to-size (or best-energy, BE) < 41 mJ/cm2 values. Patterning was even demonstrated down to 12 nm HP with one of CARs (R1UL1) evaluated for their extendibility beyond the 16 nm HP resolution. 11 nm HP patterning with some pattern collapse and well resolved patterns down 12 nm were also demonstrated with another CAR (R15UL1) formulated for 16 nm HP resolution and below. With such resist it was possible even to obtain a small process window for 14 nm HP processing with an EL ~ 8% (BE ~ 37 mJ/cm2, LER ~ 4.5 nm). Though encouraging, fulfilling all of the requirements necessary for high volume production, such as high resolution, low LER, high photon

  18. Evaluation of genomic prediction methods for fusarium head blight resistance in wheat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fusarium head blight (FHB) resistance is quantitative and difficult to evaluate. Genomic selection (GS) could accelerate FHB resistance breeding. We used US cooperative FHB wheat nursery data to evaluate GS models for several FHB resistance traits including deoxynivalenol (DON) levels. For all trait...

  19. Evaluation of drug-resistant Enterobacteriaceae in retail poultry and beef.

    PubMed

    Kilonzo-Nthenge, A; Rotich, E; Nahashon, S N

    2013-04-01

    There has been increasing concern on the emergence of multidrug-resistant foodborne pathogens from foods of animal origin, including poultry. The current study aimed to evaluate antibiotic-resistant Enterobacteriaceae from raw retail chicken/turkey parts (thigh, wings, breast, and ground) and beef meat (ground and chunks) in Middle Tennessee. Resistance of the collected Enterobacteriaceae to a panel of antibiotics was determined by the Kirby-Bauer disk diffusion test. Retail meats were also assayed for the presence of Salmonella spp. and Escherichia coli O157:H7. Two hundred thirty-seven samples representing 95.2% of the total of 249 samples tested were positive for Enterobacteriaceae. The level of contamination with Enterobacteriaceae in raw meats ranged from 3.26 log10 cfu/g to 4.94 log10 cfu/g with significant differences in counts among meat types (P < 0.05). Contamination was significantly greater (P < 0.05) in ground beef, beef chucks, ground chicken, chicken breast, and turkey wings (4.92, 4.58, 4.94, 4.75, 4.13 log10 cfu/g, respectively) than ground turkey and chicken wings (3.26 and 3.26 log10 cfu/g, respectively). Klebsiella oxytoca, Serratia spp., E. coli, and Haffnia alvei were most prevalent contaminants at 27.4, 14.3, 12.1, and 11.4%, respectively. Resistance of the Enterobacteriaceae to antimicrobials was most frequent with erythromycin, penicillin, and ampicillin at 100, 89, and 65.8%, respectively. Few (2.7%) of the Enterobacteriaceae were resistant to chloramphenicol. Salmonella spp., E. coli O157:H7, Morganella morganii, Yersinia enterocolitica, and Vibrio parahemolyticus exhibited multiple drug resistance. This investigation demonstrates that raw poultry and beef are potential reservoirs of antibiotic-resistant Enterobacteriaceae.

  20. Relationship between intrinsic surface resistance and critical current density of YBCO thin films with various thickness

    NASA Astrophysics Data System (ADS)

    Nakagawa, K.; Nakayama, S.; Saito, A.; Ono, S.; Kai, H.; Mukaida, M.; Honma, T.; Ohshima, S.

    2010-11-01

    We investigated the relationship between the intrinsic surface resistance (Rsint) and critical current density (Jc) of YBa2Cu3Oy (YBCO) film thinner than the penetration depth (λL). The measured YBCO films were deposited on CeO2-buffered r-cut Al2O3 substrates by the pulsed laser deposition method. The thicknesses of these films were 300, 200, and 100 nm, respectively. The Rsint means the surface resistance of YBCO film removing the loss by the impedance of the substrates. The effective surface resistance (Rseff) including the impedance of the substrate and the Jc of each YBCO film were measured using the dielectric resonator method at 21.8 GHz and the inductive method. We calculated Rsint by using phenomenological expressions and the Rseff value. The Rsint values of each YBCO film were almost the same in the measured temperature region. As a result, we found that Rsint was in inverse proportion to the Jc of YBCO film thinner than λL.

  1. A MATLAB-Based Boundary Data Simulator for Studying the Resistivity Reconstruction Using Neighbouring Current Pattern

    PubMed Central

    Nagaraju, J.

    2013-01-01

    Phantoms are essentially required to generate boundary data for studying the inverse solver performance in electrical impedance tomography (EIT). A MATLAB-based boundary data simulator (BDS) is developed to generate accurate boundary data using neighbouring current pattern for assessing the EIT inverse solvers. Domain diameter, inhomogeneity number, inhomogeneity geometry (shape, size, and position), background conductivity, and inhomogeneity conductivity are all set as BDS input variables. Different sets of boundary data are generated by changing the input variables of the BDS, and resistivity images are reconstructed using electrical impedance tomography and diffuse optical tomography reconstruction software (EIDORS). Results show that the BDS generates accurate boundary data for different types of single or multiple objects which are efficient enough to reconstruct the resistivity images for assessing the inverse solver. It is noticed that for the BDS with 2048 elements, the boundary data for all inhomogeneities with a diameter larger than 13.3% of that of the phantom are accurate enough to reconstruct the resistivity images in EIDORS-2D. By comparing the reconstructed image with an original geometry made in BDS, it would be easier to study the inverse solver performance and the origin of the boundary data error can be identified. PMID:27006909

  2. Albumin coatings by alternating current electrophoretic deposition for improving corrosion resistance and bioactivity of titanium implants.

    PubMed

    Höhn, Sarah; Braem, Annabel; Neirinck, Bram; Virtanen, Sannakaisa

    2017-04-01

    Although Ti alloys are generally regarded to be highly corrosion resistant, inflammatory conditions following surgery can instigate breakdown of the TiO2 passivation layer leading to an increased metal ion release. Furthermore proteins present in the surrounding tissue will readily adsorb on a titanium surface after implantation. In this paper alternating current electrophoretic deposition (AC-EPD) of bovine serum albumin (BSA) on Ti6Al4V was investigated in order to increase the corrosion resistance and control the protein adsorption capability of the implant surface. The Ti6Al4V surface was characterized with SEM, XPS and ToF-SIMS after long-term immersion tests under physiological conditions and simulated inflammatory conditions either in Dulbecco's Modified Eagle Medium (DMEM) or DMEM supplemented with fetal calf serum (FCS). The analysis showed an increased adsorption of amino acids and proteins from the different immersion solutions. The BSA coating was shown to prevent selective dissolution of the vanadium (V) rich β-phase, thus effectively limiting metal ion release to the environment. Electrochemical impedance spectroscopy measurements confirmed an increase of the corrosion resistance for BSA coated surfaces as a function of immersion time due to the time-dependent adsorption of the different amino acids (from DMEM) and proteins (from FCS) as observed by ToF-SIMS analysis.

  3. Qualification of MCP BSCCO 2212 bulk material for use in resistive current limiters

    NASA Astrophysics Data System (ADS)

    Elschner, S.; Breuer, F.; Noe, M.; Wolf, A.; Bock, J.

    2002-08-01

    Melt cast processed BSCCO 2212 is a very promising material option for use in resistive current limiters. The required compact elements with long conductor lengths can be manufactured by cutting tubes to bifilar coils. The critical current density and its homogeneity were examined on such coils at the projected operation temperature T=65 K. As a result we obtain Jc=3960 A/cm 2 ±5%. It was also shown, that the coils can be equipped with a metallic shunt. In addition the limiting behaviour of the material and the reliability of the electric bypass were tested on shunted 5 mm-rods. Effective limiting was achieved at any load up to 100 V/m.

  4. Teacher Evaluation: An Annotated Bibliography. Current Bibliography No. 8.

    ERIC Educational Resources Information Center

    Blount, Gail, Comp.

    Three interrelated frames of reference -- the purposes of evaluation, the criteria for evaluation, and the evaluators -- form the basis of the major subject divisions of this bibliography. Part one consists of general material on teacher evaluation, teacher effectiveness, and supervisory practices. Attempts to determine the qualities of a good…

  5. Course Evaluation Study in Europe: The Current Picture

    NASA Astrophysics Data System (ADS)

    Rojas, Israel Gutiérrez; Crespo, Raquel M.; Leony, Derick; Pardo, Abelardo; Kloos, Carlos Delgado

    Course evaluation is one of the key processes in the educational context that is in charge of the assurance of quality of courses taught in an institution. Although it is an essential process realized in every institution, the procedure followed for course evaluation does not comply with any evaluation standard. The objectives of this document are: to define a course evaluation concept map to understand better the needs of this field; to analyze the course evaluation standard ISO/IEC 19796, the only standard for course evaluation; and finally, to carry out a study of European institutions evaluation processes to determine why anyone is using standards in this learning process.

  6. Measurements of the transverse resistance and eddy current losses in a cable-in-conduit conductor

    NASA Astrophysics Data System (ADS)

    Keilin, V. E.; Kovalev, I. A.; Kruglov, S. L.; Lelekhov, S. A.; Il'in, A. A.; Naumov, A. V.; Shcherbakov, V. I.; Shutov, K. A.

    2015-11-01

    In the case of plasma current interruption in tokamaks, the conductor of toroidial field (TF) coils experiences the action of a pulsed decreasing magnetic field (PDMF) parallel to the conductor's axis. To estimate the stability of a cable-in-conduit conductor against the PDMF, a new experimental method to study different types of losses is applied. This method exploits a high sensitivity of temperature and gas pressure to input energy in a closed volume. It allows one to measure hysteresis losses with a rather high accuracy (provided that the rate of change of the PDMF is low) and a sum of hysteresis losses and eddy current losses (when the rate of change of the PDMF is high). An experimental setup to measure the transverse (circumferential) resistance and losses has been developed at the National Research Centre Kurchatov Institute. A Russianmade Nb3Sn conductor intended for the TF coils of the International Thermonuclear Experimental Reactor is subjected to a PDMF with different amplitudes and characteristic times. The electromagnetic time constant and the transverse resistivity of the conductor are experimentally determined. The maximum temperature of strands under the action of the PDMF is calculated.

  7. Evaluation of fusiform rust-resistant loblolly pine families for the South Carolina sandhills region

    SciTech Connect

    Powers, H.R. Jr.

    1981-10-01

    Loblolly pine trees from various geographic sources are being evaluated for resistance to fusiform rust. Reasons for differences in resistance and the mechanisms of rust infection are also being investigated. (ACR)

  8. The Effect of By-pass Current on the Accuracy of Resistivity Measurement in a Diamond Anvil Cell

    NASA Astrophysics Data System (ADS)

    Yang, Jie; Peng, Gang; Liu, Cai-Long; Lu, Han; Han, Yong-Hao; Gao, Chun-Xiao

    2013-06-01

    We report a quantitative analysis of by-pass current effect on the accuracy of resistivity measurement in a diamond anvil cell. Due to the by-pass current, the sample resistivity calculated by the van der Pauw method is obviously smaller than the actual value and the problem becomes more serious for a high-resistivity sample. For the consideration of high accuracy of resistivity measurement, a method is presented that the inside wall of the sample chamber should be covered by a polymethylmethane layer. With this highly insulating layer, the by-pass current is effectively prevented and the current density distribution inside the sample is very close to the ideal case.

  9. Evaluation of chronic kidney disease in chronic heart failure: From biomarkers to arterial renal resistances

    PubMed Central

    Iacoviello, Massimo; Leone, Marta; Antoncecchi, Valeria; Ciccone, Marco Matteo

    2015-01-01

    Chronic kidney disease and its worsening are recurring conditions in chronic heart failure (CHF) which are independently associated with poor patient outcome. The heart and kidney share many pathophysiological mechanisms which can determine dysfunction in each organ. Cardiorenal syndrome is the condition in which these two organs negatively affect each other, therefore an accurate evaluation of renal function in the clinical setting of CHF is essential. This review aims to revise the parameters currently used to evaluate renal dysfunction in CHF with particular reference to the usefulness and the limitations of biomarkers in evaluating glomerular dysfunction and tubular damage. Moreover, it is reported the possible utility of renal arterial resistance index (a parameter associated with abnormalities in renal vascular bed) for a better assesment of kidney disfunction. PMID:25610846

  10. State-Mandated Principal Evaluation: A Report on Current Practice.

    ERIC Educational Resources Information Center

    Peters, Stephen; Bagenstos, Naida Tushnet

    State-mandated practices for evaluation of principals are described. Most such programs draw on three bodies of literature concerning management and organizational theory, personnel evaluation, and effective principalship. In most evaluations, four concerns are constant: (1) supervision and staff development; (2) school and community relations;…

  11. Computer Dissemination of Current Literature, An Over-All Evaluation.

    ERIC Educational Resources Information Center

    Sage, C. R.

    A resume of the Ames Laboratory Selective Dissemination of Information (SDI) Computer System is presented. The results of three types of evaluation studies made of the Ames Laboratory SDI systems are discussed which include: evaluation of model studies utilizing restricted document and user sample sizes; statistical evaluation of production runs…

  12. [Current evaluation of teratogenic and fetotoxic effects of psychotropic drugs].

    PubMed

    Watanabe, Omi

    2014-01-01

    Psychiatric disorders are equally common among pregnant and non-pregnant women, and many of these conditions are treated with psychotropic medications. The use of psychotropic medicines during pregnancy, especially antidepressants, became increasingly prevalent in the early 2000's, although many physicians prefer not to prescribe drugs for pregnant women due to concerns about teratogenicity. Current data on the risks of in utero exposure to psychotropic medications are limited, leaving women and physicians to make difficult decisions regarding the initiation or maintenance of treatment during pregnancy without a complete knowledge of the risks. Of all the psychotropics, antidepressant use in pregnancy has been relatively well studied. However, available studies have not yet adequately controlled for other factors that may influence birth outcomes, including maternal illness or problematic health-related behaviors such as smoking and alcohol use during pregnancy. This review focuses on the use of selective serotonin reuptake inhibitors (SSRIs) during pregnancy, the antidepressants most commonly used to treat depression. In the evaluation of medication during pregnancy, teratogenicity and fetotoxicity must be considered. Most studies on the use of SSRIs during the first trimester of pregnancy have not shown an increase in the overall risk of major malformations, although several studies have suggested that SSRIs may be associated with a small increased risk of cardiovascular malformations, mainly involving ventricular and atrial septal defects. In addition to structural malformations, drugs were also observed to induce other adverse effects. Since SSRIs readily cross the placenta, concern has been raised about the short- or long-term effects of prenatal exposure to SSRIs on the developing offspring. Epidemiological studies have documented that 10-30% of neonates exposed to SSRIs near term had poor neonatal adaptation syndrome (PNAS). Some studies reported that

  13. EVALUATION METHODOLOGY FOR PROLIFERATION RESISTANCE AND PHYSICAL PROTECTION OF GENERATION IV NUCLEAR ENERGY SYSTEMS: AN OVERVIEW.

    SciTech Connect

    BARI, R.; ET AL.

    2006-03-01

    information important to the evaluation methodology users and to the decisions of a proliferant State or adversary. They are first evaluated for segments and then aggregated for complete pathways. Results are aggregated as appropriate to permit pathway comparisons and system assessment. The paper highlights the current achievements in the development of the Proliferation Resistance and Physical Protection Evaluation Methodology. The way forward is also briefly presented together with some conclusions.

  14. Evaluation Methodology For Proliferation Resistance And Physical Protection Of Generation IV Nuclear Energy Systems: An Overview

    SciTech Connect

    T. Bjornard; R. Bari; R. Nishimura; P. Peterson; J. Roglans; D. Bley; J. Cazalet; G.G.M. Cojazzi; P. Delaune; M. Golay; G. Rendad; G. Rochau; M. Senzaki; I. Therios; M. Zentner

    2006-05-01

    information important to the evaluation methodology users and to the decisions of a proliferant State or adversary. They are first evaluated for segments and then aggregated for complete pathways. Results are aggregated as appropriate to permit pathway comparisons and system assessment. The paper highlights the current achievements in the development of the Proliferation Resistance and Physical Protection Evaluation Methodology. The way forward is also briefly presented together with some conclusions.

  15. Application of resistivity monitoring to evaluate cement grouting effect in earth filled dam

    SciTech Connect

    Kim, Jin-Mo; Yoon, Wang-Jung

    2015-03-10

    In this paper, we applied electrical resistivity monitoring method to evaluate the cement grouting effect. There are a lot of ways to evaluate cement grouting effect. In order to do this evaluation in a great safety, high efficiency, and lower cost, resistivity monitoring is found to be the most appropriate technique. In this paper we have selected a dam site from Korea to acquire resistivity monitoring data and compare the results of inversion to estimate the cement grouting effect.

  16. Evaluation of leptin and insulin resistance in patients with cholelithiasis.

    PubMed

    Atamer, Aytaç; Ovünç, Ayşe Oya Kurdaş; Yeşil, Atakan; Atamer, Yildiz

    2013-08-01

    The association between insulin resistance, lipoproteins and leptin was evaluated in cholelithiasis. The study group included 55 women (68.8%) and 25 men (31.3%) with a mean age and SD of 50.56 +/- 14.28 yrs. The control group included 25 women (62.5%) and 15 men (37.5%) with a mean age of 50.93 +/- 11.73 yrs. Serum leptin levels were measured by the enzyme immunoassay method. HOMA-IR was determined by using fasting glucose and insulin levels. Insulin, total cholesterol (TC), LDL-C, HOMA-IR (p < 0.01) and leptin (p < 0.001) were significantly higher in the cholelithiasis group, compared to the controls. In patients with a HOMA-IR >2.2, age, body mass index (BMI), glucose, insulin, triglycerides (TG), TC and leptin levels were higher than in patients with a HOMA-IR < 2.2. In patients with glucose levels >100 mg/dl, mean BMI, HOMA-IR, insulin, TG, TC and leptin levels were significantly higher than in patients with glucose levels <100 mg/dl. In patients with TG levels >150 mg/dl, mean age, BMI, glucose, insulin, TC, leptin and HOMA-IR were significantly higher than in patients with TG levels < 150 mg/dl. In patients with BMI > 25 kg/m2, mean age, glucose, insulin, TG, TC, leptin, HOMA-IR were significantly higher than in patients with BMI < 25. In cholelithiasis group, there was a positive correlation between leptin and age, BMI, glucose, insulin, TG, TC, LDL-C or HOMA-IR. In conclusion, we found a positive association between increased leptin levels and abnormal lipoprotein metabolism in cholelithiasis. Cholelithiasis subjects with insulin resistance showed higher cardiometabolic risk factors than those without it.

  17. Overview on current status of biotechnological interventions on yellow stem borer Scirpophaga incertulas (Lepidoptera: Crambidae) resistance in rice.

    PubMed

    Deka, Sikha; Barthakur, Sharmistha

    2010-01-01

    Yellow stem borer (YSB), Scirpophaga incertulas (Lepidoptera: Crambidae), a monophagous pest of paddy is considered as most important pest of rain fed low land and flood prone rice eco-systems. Breeding of yellow stem borer resistance in rice is difficult owing to the complex genetics of the trait, inherent difficulties in screening and poor understanding of the genetics of resistance. On the other hand, a good level of resistance against the widespread yellow stem borer has been rare in the rice germplasm. Resistance to insects has been demonstrated in transgenic plants expressing genes for delta-endotoxins from Bacillus thuringiensis (Bt), protease inhibitors, enzymes and plant lectins. The performance of insect resistant GM rice in trials in China has been quite impressive. The present review is an attempt to assess the current state of development in biotechnological intervention for yellow stem borer resistance in rice.

  18. Visco-resistive plasmoid instability in Sweet-Parker current sheets

    NASA Astrophysics Data System (ADS)

    Grasso, Daniela; Comisso, Luca

    2016-10-01

    The linear analysis by Loureiro et al. is generalized to investigate the plasmoid instability in visco-resistive Sweet-Parker sheets. We cover both the linear and nonlinear growth of the plasmoids. The linear growth rate and the wavenumber scale as S 1 / 4 (1 +Pm)- 5 / 8 and S 3 / 8 (1 +Pm)- 3 / 16 with respect to the Lundquist number S and the magnetic Prandtl number Pm. The growth of the plasmoids slows down from an exponential growth to an algebraic growth when they enter into the nonlinear regime. The time-scale of the nonlinear growth of the plasmoids is found to be τNL S - 3 / 16 (1 +Pm)19/32τA , L . We also discuss how the plasmoid instability can enable fast magnetic reconnection in visco-resistive plasmas. In this regime, the global reconnection rate is shown to be 0.01vA , uBu (1 +Pm)- 1 / 2. The same author will present another poster in a closely related topic: ``Generalized Plasmoid Instability in Time Evolving Current Sheets''. Hence, we request the committee to ensure that these 2 posters are placed alongside each other.

  19. Immunotherapy in castration-resistant prostate cancer: integrating sipuleucel-T into our current treatment paradigm.

    PubMed

    Garcia, Jorge A; Dreicer, Robert

    2011-03-01

    The availability of several novel antibodies, coupled with viral, DNA, and dendritic-cell vaccines, has renewed interest in immunotherapeutic approaches to the treatment of advanced prostate cancer. Although promising, none of these approaches have led to major clinical activity, and in the case of cell-based immunotherapy with GVAX, new concerns about safety arose when this therapy was used in the castration-resistant setting. A more attractive yet toxic approach has also utilized a check-point blockade with CTLA-4 antibodies. Although initial clinical efficacy has been observed, toxicity appears to be the major limitation of its use in prostate cancer. Sipuleucel-T (Provenge) is an autologous active cellular immunotherapy product that includes autologous dendritic cells pulsed ex vivo with PAP2024, a recombinant fusion protein made of prostatic acid phosphataase (PAP) and granulocyte-macrophage colony-stimulating factor (GM-CSF). Despite the lack of objective anti-tumor activity seen with sipuleucel-T, a recently reported phase III trial demonstrated a significant improvement in the overall survival of men with asymptomatic, minimally symptomatic metastatic castration-resistant prostate cancer (CRPC). This agent is the first FDA-approved novel immunotherapeutic compound for the treatment of a solid malignancy. A better understanding of how clinicians should incorporate this novel agent into the current management of CRPC is needed.

  20. Current advance methods for the identification of blast resistance genes in rice.

    PubMed

    Tanweer, Fatah A; Rafii, Mohd Y; Sijam, Kamaruzaman; Rahim, Harun A; Ahmed, Fahim; Latif, Mohammad A

    2015-05-01

    Rice blast caused by Magnaporthe oryzae is one of the most devastating diseases of rice around the world and crop losses due to blast are considerably high. Many blast resistant rice varieties have been developed by classical plant breeding and adopted by farmers in various rice-growing countries. However, the variability in the pathogenicity of the blast fungus according to environment made blast disease a major concern for farmers, which remains a threat to the rice industry. With the utilization of molecular techniques, plant breeders have improved rice production systems and minimized yield losses. In this article, we have summarized the current advanced molecular techniques used for controlling blast disease. With the advent of new technologies like marker-assisted selection, molecular mapping, map-based cloning, marker-assisted backcrossing and allele mining, breeders have identified more than 100 Pi loci and 350 QTL in rice genome responsible for blast disease. These Pi genes and QTLs can be introgressed into a blast-susceptible cultivar through marker-assisted backcross breeding. These molecular techniques provide timesaving, environment friendly and labour-cost-saving ways to control blast disease. The knowledge of host-plant interactions in the frame of blast disease will lead to develop resistant varieties in the future.

  1. Current concepts on the virulence mechanisms of meticillin-resistant Staphylococcus aureus

    PubMed Central

    David, Michael Z.; Salata, Robert A.

    2012-01-01

    Meticillin-resistant Staphylococcus aureus (MRSA) strains are prevalent bacterial pathogens that cause both health care and community-associated infections. Increasing resistance to commonly prescribed antibiotics has made MRSA a serious threat to public health throughout the world. The USA300 strain of MRSA has been responsible for an epidemic of community-associated infections in the US, mostly involving skin and soft tissue but also more serious invasive syndromes such as pneumonia, severe sepsis and endocarditis. MRSA strains are particularly serious and potentially lethal pathogens that possess virulence mechanisms including toxins, adhesins, enzymes and immunomodulators. One of these is Panton–Valentine leukocidin (PVL), a toxin associated with abscess formation and severe necrotizing pneumonia. Earlier studies suggested that PVL was a major virulence factor in community-associated MRSA infections. However, some recent data have not supported this association while others have, leading to controversy. Therefore, investigators continue to search for additional mechanisms of pathogenesis. In this review, we summarize the current understanding of the biological basis of MRSA virulence and explore future directions for research, including potential vaccines and antivirulence therapies under development that might allow clinicians to more successfully treat and prevent MRSA infections. PMID:22745137

  2. Mapping of top of permafrost using a direct current resistivity survey

    SciTech Connect

    Gilmore, T.J.; Clayton, E.A.

    1995-10-01

    Data from a direct current resistivity survey and geologic logs from boreholes were used to map the top of permafrost at a remote Air Force installation in Alaska. This study resulted from a remedial investigation that was conducted at Eielson Air Force base near Fairbanks, Alaska under the federal Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) regulations. The depth and continuity of the permafrost was important in determining the fate of petroleum contamination that was inadvertently discharged to the ground during earlier Air Force operations. The results indicate that the top of permafrost forms a highly irregular surface. In general, however, the top of permafrost forms a diagonal ridge at the center of the contour grid that is bordered on each side by troughs.

  3. Liquid nitrogen cooled integrated power electronics module with high current carrying capability and lower on resistance

    NASA Astrophysics Data System (ADS)

    Ye, Hua; Lee, Changwoo; Simon, Randy W.; Haldar, Pradeep; Hennessy, Michael J.; Mueller, Eduard K.

    2006-11-01

    This letter presents the development of high-performance integrated cryogenic power modules, where both driver components and power metal-oxide semiconductor field-effect transistors are integrated in a single package, to be used in a 50kW prototype cryogenic inverter operating at liquid nitrogen temperature. The authors have demonstrated a compact high-voltage, cryogenic integrated power module that exhibited more than 14 times improvement in on-resistance and continuous current carrying capability exceeding 40A. The modules are designed to operate at liquid nitrogen temperature with extreme thermal cycling. The power electronic modules are necessary components that provide control and switching for second generation, yttrium barium copper oxide-based high temperature superconductor devices including cables, motors, and generators.

  4. Coil in coil - components for the high voltage superconducting resistive current limiter CULT 110

    NASA Astrophysics Data System (ADS)

    Elschner, S.; Stemmle, M.; Breuer, F.; Walter, H.; Frohne, C.; Noe, M.; Bock, J.

    2008-02-01

    The German government (BMBF/VDI) funded project CULT 110 is presently the largest European current limiter project and aims at the development of a one-phase resistive limiter for the voltage level of 110 kV. The contribution presents the actual state of development of the superconducting components. As in the successful predecessor project CURL 10 these are made of melt cast processed BSCCO 2212 bulk material, however monofilar instead of bifilar coils are used. The electrical protection concept is based on a normal conducting coil arranged around a superconducting coil and connected in parallel. Simultaneously this coil serves as an electrical bypass and, under fault conditions, generates a magnetic field for quench homogenisation. Since no continuously connected shunt is needed, a much higher voltage during faults can be applied. The rules for an optimum superconductor and coil design are given and the viability of the whole concept is demonstrated by both, experiment and numerical simulation.

  5. The Evaluation of Music Faculty in Higher Education: Current Practices

    ERIC Educational Resources Information Center

    Parkes, Kelly A.

    2015-01-01

    The purpose of this research was to ascertain the methods used to evaluate music faculty and whether achievement measures, or student progress, impact the evaluations made about teacher effectiveness for music faculty in the higher education context. The author surveyed Chairs of Departments or Directors of Schools of Music (n = 412) listed as…

  6. EVALUATION OF CURRENT SUSTAINABILITY ASSESSMENT OF BIOBASED TECHNOLOGY

    EPA Science Inventory

    Sustainable technology is driven by economic competitiveness, government policies and public pressure. The claim of inherent cleanliness for biotechnology is too simplistic. Each application of biotechnology must be evaluated for suitable characteristics of sustainability. The ...

  7. FBI fingerprint identification automation study: AIDS 3 evaluation report. Volume 5: Current system evaluation

    NASA Technical Reports Server (NTRS)

    Mulhall, B. D. L.

    1980-01-01

    The performance, costs, organization and other characteristics of both the manual system and AIDS 2 were used to establish a baseline case. The results of the evaluation are to be used to determine the feasibility of the AIDS 3 System, as well as provide a basis for ranking alternative systems during the second phase of the JPL study. The results of the study were tabulated by subject, scope and methods, providing a descriptive, quantitative and qualitative analysis of the current operating systems employed by the FBI Identification Division.

  8. Evaluation of natural and engineered resistance mechanisms in potato against Colorado potato beetle in a no-choice field study.

    PubMed

    Cooper, Susannah G; Douches, David S; Coombs, Joseph J; Grafius, Edward J

    2007-04-01

    The Colorado potato beetle, Leptinotarsa decemlineata Say, is the major insect pest of potato, Solanum tuberosum L., in eastern North America and is renowned for resistance development, currently resistant to >40 insecticides worldwide. Host plant resistance may assist in delaying in resistance development to insecticides. We evaluated natural host plant resistance mechanisms (glandular trichomes and Solanum chacoense Bitter-derived resistance) and engineered resistance mechanisms (Bacillus thuringiensis [Bt] Berliner cry3A and cry1Ia1) in a no-choice cage study. Six different potato lines representing four host plant resistance mechanisms were evaluated over 2 yr. Egg masses were placed in each cage (one egg mass per plant). Almost no feeding was observed in the Bt-cry3A lines, and only minor feeding was observed in the Bt-cry1Ia1 lines in either year. On the S. chacoense-derived line, there was significantly less defoliation than on either the susceptible line or the glandular trichome line in 2003. In 2004, there was significantly higher defoliation on the S. chacoense-derived line than on the susceptible line or glandular trichome line. The defoliation of the Solanum chacoense-derived line was largely due to larvae clipping the petioles, rather than consumption of the leaves. Defoliation on the glandular trichome line did not differ significantly from the defoliation of the susceptible line, suggesting glandular trichomes may not be effective in controlling larvae and preventing defoliation. This study suggested that Bt can provide high levels of resistance, but the natural resistance mechanisms tested here are variable for control of Colorado potato beetle larvae in no-choice situations.

  9. Evaluation of the capacitively coupled resistivity (line antenna) method for the characterization of vadose zone dynamics

    NASA Astrophysics Data System (ADS)

    Niu, Qifei; Wang, Yu-Hsing; Zhao, Kairan

    2014-07-01

    The electrical resistivity survey, traditionally realized by the direct current (DC) resistivity method, has shown great value for characterizing vadose zone dynamics. Compared with the DC resistivity method, the capacitively coupled (CC) resistivity method has a higher ratio of measurement speed to data density, and thus is economically preferred for resistivity surveys that require high data density, e.g., hydrological characterizations. To test the applicability of the CC resistivity method to the study of vadose zone dynamics, we conducted time-lapse resistivity surveys using a commercial CC resistivity (line antenna) system, the OhmMapper, to monitor the water content change in an unsaturated zone due to artificial rainfall infiltration. Special considerations were paid to the inversion of CC resistivity (line antenna) measurements in order to increase the accuracy of inversion results. The derived resistivity of the subsurface clearly captures the water movement in the vadose zone and shows the applicability of the CC resistivity method. The experiment also showed a limitation of the equipment: when the ground surface became extremely conductive, the OhmMapper falsely interpreted the current level. If the wrong current level is identified in the measurement, the measured resistance should be corrected accordingly. The overestimation of the ground resistivity of the CC resistivity method, arising from the decrease in the ground resistivity, was also examined and discussed. Although the measurement bias was found to be negligible in our study, one should still be cautious about it when using the CC resistivity method for similar applications, especially when the measurement is made with a short dipole cable.

  10. Mesoscopic current transport in two-dimensional materials with grain boundaries: Four-point probe resistance and Hall effect

    NASA Astrophysics Data System (ADS)

    Lotz, Mikkel R.; Boll, Mads; Østerberg, Frederik W.; Hansen, Ole; Petersen, Dirch H.

    2016-10-01

    We have studied the behavior of micro four-point probe (M4PP) measurements on two-dimensional (2D) sheets composed of grains of varying size and grain boundary resistivity by Monte Carlo based finite element (FE) modelling. The 2D sheet of the FE model was constructed using Voronoi tessellation to emulate a polycrystalline sheet, and a square sample was cut from the tessellated surface. Four-point resistances and Hall effect signals were calculated for a probe placed in the center of the square sample as a function of grain density n and grain boundary resistivity ρ GB . We find that the dual configuration sheet resistance as well as the resistance measured between opposing edges of the square sample have a simple unique dependency on the dimension-less parameter √{ n } ρ GB G 0 , where G0 is the sheet conductance of a grain. The value of the ratio R A / R B between resistances measured in A- and B-configurations depends on the dimensionality of the current transport (i.e., one- or two-dimensional). At low grain density or low grain boundary resistivity, two-dimensional transport is observed. In contrast, at moderate grain density and high grain resistivity, one-dimensional transport is seen. Ultimately, this affects how measurements on defective systems should be interpreted in order to extract relevant sample parameters. The Hall effect response in all M4PP configurations was only significant for moderate grain densities and fairly large grain boundary resistivity.

  11. Endoscopic Evaluation of Adenoids: Reproducibility Analysis of Current Methods

    PubMed Central

    Hermann, Juliana Sato; Sallum, Ana Carolina; Pignatari, Shirley Shizue Nagata

    2013-01-01

    Objectives To investigate intra- and interexaminers' reproducibility of usual adenoid hypertrophy assessment methods, according to nasofiberendoscopic examination. Methods Forty children of both sexes, ages ranging between 4 and 14 years, presenting with nasal obstruction and oral breathing suspected to be caused by adenoid hypertrophy, were enrolled in this study. Patients were evaluated by nasofiberendoscopy, and records were referred to and evaluated by two experienced otolaryngologists. Examiners analysed the records according to different evaluation methods; i.e., estimated, and measured percentage of choanal occlusion; as well as subjective and objective classificatory systems of adenoid hypertrophy. Results Data disclosed excellent intraexaminer reproducibility for both estimated and measured choanal occlusion. analysis revealed lower reproducibility rates of estimated in relation to measured choanal occlusion. Measured choanal occlusion also demonstrated less agreement among evaluations made through the right and left sides of the nasal cavity. Alternatively, intra- and interexaminers reliability analysis revealed higher agreement for subjective than objective classificatory system. Besides, subjective method demonstrated higher agreement than the objective classificatory system, when opposite sides were compared. Conclusion Our results suggest that measured is superior to estimated percentage of choanal occlusion, particularly if employed bilaterally, diminishing the lack of agreement between sides. When adenoid categorization is used instead, the authors recommend subjective rather than objective classificatory system of adenoid hypertrophy. PMID:23526477

  12. Methods to evaluate and update current phosphorus indices

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In most states, the phosphorus (P) index (PI) is the adopted strategy for assessing a field’s vulnerability to P loss when preparing comprehensive nutrient management plans. Most state PIs, however, have not been rigorously evaluated against measured P loss data to determine how well the PI assigns ...

  13. Formation of a spark discharge in an inhomogeneous electric field with current limitation by a large ballast Resistance

    SciTech Connect

    Baldanov, B. B.

    2016-01-15

    Results of studies of a spark discharge initiated in argon in a point–plane electrode gap with limitation of the discharge current by a large ballast resistance are presented. It is shown that the current flowing through the plasma channel of such a low-current spark has the form of periodic pulses. It is experimentally demonstrated that, when a low-current spark transforms into a constricted glow discharge, current pulses disappear, the spatial structure of the cathode glow changes abruptly, and a brightly glowing positive plasma column forms in the gap.

  14. Transcranial direct current stimulation in a patient with therapy-resistant major depression.

    PubMed

    Palm, Ulrich; Keeser, Daniel; Schiller, Christina; Fintescu, Zoe; Reisinger, Eva; Baghai, Thomas C; Mulert, Christoph; Padberg, Frank

    2009-01-01

    Transcranial direct current stimulation (tDCS) of the prefrontal cortex (PFC) has been reported to exert significant antidepressant effects in patients with major depression. Several recent studies found an improvement of depressive symptoms in drug-free patients. Here we report the case of a 66-year-old female patient suffering from recurrent major depressive episodes who underwent anodal tDCS of the left dorsolateral PFC over 4 weeks as an add-on treatment to a stable antidepressant medication. Only a modest improvement of depressive symptoms was observed after tDCS, i.e. reduction of the baseline scores in the Hamilton Depression Rating Scale from 23 to 19 and in the Beck Depression Inventory from 27 to 20. However, there was an increase from 52 to 90% in the Regensburg Verbal Fluency Test. In addition, EEG was used to assess the acute effects of tDCS. Low resolution brain electromagnetic tomography (LORETA) showed a left unilateral focal effect (25-40% reduced power) in the delta, theta and alpha frequency bands. The same effect appeared in the surface analysis of the EEG. The absolute, as well as the relative power decreased significantly in the delta, theta and alpha bands after a comparison of the spectral analysis. Though tDCS over 4 weeks did not exert clinically meaningful antidepressant effects in this case of therapy-resistant depression, the findings for cognitive measures and EEG suggest that beneficial effects may occur in depressed subjects and future studies need to further explore this approach also in therapy-resistant major depression.

  15. Evaluation of Idaho's DARE "Drug Abuse Resistance Education Projects."

    ERIC Educational Resources Information Center

    Silva, Roberta K.

    The goal of DARE (Drug Abuse Resistance Education) is not to completely eliminate the drug and alcohol problems of society. It is a proactive prevention program designed to equip youth (focusing on elementary school) with skills for resisting peer pressure to experiment with drugs, and to manage anger without resorting to violence or the use of…

  16. Three inoculation methods for evaluating Sclerotinia blight resistance in peanut

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Laboratory-based assays for screening germplasm for resistance to Sclerotinia blight in peanuts can be conducted year-round, and thus may accelerate progress in breeding for resistant plants. Three previously proposed inoculation methods (using main stems of intact plants, detached main stems, or de...

  17. Geophysical investigation of Red Devil mine using direct-current resistivity and electromagnetic induction, Red Devil, Alaska, August 2010

    USGS Publications Warehouse

    Burton, Bethany L.; Ball, Lyndsay B.

    2011-01-01

    Red Devil Mine, located in southwestern Alaska near the Village of Red Devil, was the state's largest producer of mercury and operated from 1933 to 1971. Throughout the lifespan of the mine, various generations of mills and retort buildings existed on both sides of Red Devil Creek, and the tailings and waste rock were deposited across the site. The mine was located on public Bureau of Land Management property, and the Bureau has begun site remediation by addressing mercury, arsenic, and antimony contamination caused by the minerals associated with the ore deposit (cinnabar, stibnite, realgar, and orpiment). In August 2010, the U.S. Geological Survey completed a geophysical survey at the site using direct-current resistivity and electromagnetic induction surface methods. Eight two-dimensional profiles and one three-dimensional grid of direct-current resistivity data as well as about 5.7 kilometers of electromagnetic induction profile data were acquired across the site. On the basis of the geophysical data and few available soil borings, there is not sufficient electrical or electromagnetic contrast to confidently distinguish between tailings, waste rock, and weathered bedrock. A water table is interpreted along the two-dimensional direct-current resistivity profiles based on correlation with monitoring well water levels and a relatively consistent decrease in resistivity typically at 2-6 meters depth. Three settling ponds used in the last few years of mine operation to capture silt and sand from a flotation ore processing technique possessed conductive values above the interpreted water level but more resistive values below the water level. The cause of the increased resistivity below the water table is unknown, but the increased resistivity may indicate that a secondary mechanism is affecting the resistivity structure under these ponds if the depth of the ponds is expected to extend below the water level. The electromagnetic induction data clearly identified the

  18. Using Ecological Momentary Assessment to Evaluate Current Physical Activity

    PubMed Central

    Marszalek, Jolanta; Morgulec-Adamowicz, Natalia; Rutkowska, Izabela; Kosmol, Andrzej

    2014-01-01

    Objective. The purpose of this study was to assess the value of ecological momentary assessment in evaluating physical activity among children, adolescents, and adults. It also determines whether ecological momentary assessment fulfills the criteria of validity, reliability, objectivity, norms, and standardization applied to the tools used for the evaluation of physical activity. Methods. The EBSCO-CINHAL, Medline, PsycINFO, PubMed, and SPORTDiscuss databases were reviewed in December 2012 for articles associated with EMA. Results. Of the 20 articles examined, half (10) used electronic methods for data collection, although various methods were used, ranging from pen and paper to smartphone applications. Ten studies used objective monitoring equipment. Nineteen studies were performed over 4 days. While the validity of the EMA method was discussed in 18 studies, only four found it to be objective. In all cases, the EMA procedures were precisely documented and confirmed to be feasible. Conclusions. Ecological momentary assessment is a valid, reliable, and feasible approach to evaluate activity and sedentary behavior. Researchers should be aware that while ecological momentary assessment offers many benefits, it simultaneously imposes many limitations which should be considered when studying physical activity. PMID:25126580

  19. Development and evaluation of a tampering resistant transdermal fentanyl patch.

    PubMed

    Cai, Bing; Engqvist, Håkan; Bredenberg, Susanne

    2015-07-05

    With the increasing number of misuse and abuse of opioids, the resistance to tampering becomes an important attribute for transdermal opioid patches. In this study, drug-containing geopolymer granules were integrated into an adhesive matrix to improve the resistance of fast drug release against some common abuse techniques. Bench testing showed that fentanyl loaded geopolymer granules had better resistance to tampering compared to a commercial fentanyl patch. Moreover, in a pilot in vivo study on a few rats, the granules showed potential to give similar drug plasma concentrations as the commercial fentanyl patch. After integrating geopolymer granules into an adhesive matrix, the new patch showed a better resistance against the investigated tampering tests compared with the commercially available patch. In this study, we showed that incorporating drug loaded geopolymer granules into a patch adhesive has potential to improve the resistance of the fentanyl patch against tampering without compromising the drug release.

  20. Ligand-targeted particulate nanomedicines undergoing clinical evaluation: current status.

    PubMed

    van der Meel, Roy; Vehmeijer, Laurens J C; Kok, Robbert J; Storm, Gert; van Gaal, Ethlinn V B

    2013-10-01

    Since the introduction of Doxil® on the market nearly 20years ago, a number of nanomedicines have become part of treatment regimens in the clinic. With the exception of antibody-drug conjugates, these nanomedicines are all devoid of targeting ligands and rely solely on their physicochemical properties and the (patho)physiological processes in the body for their biodistribution and targeting capability. At the same time, many preclinical studies have reported on nanomedicines exposing targeting ligands, or ligand-targeted nanomedicines, yet none of these have been approved at this moment. In the present review, we provide a concise overview of 13 ligand-targeted particulate nanomedicines (ligand-targeted PNMs) that have progressed into clinical trials. The progress of each ligand-targeted PNM is discussed based on available (pre)clinical data. Main conclusions of these analyses are that (a) ligand-targeted PNMs have proven to be safe and efficacious in preclinical models; (b) the vast majority of ligand-targeted PNMs is generated for the treatment of cancer; (c) contribution of targeting ligands to the PNM efficacy is not unambiguously proven; and (d) targeting ligands do not cause localization of the PNM within the target tissue, but rather provide benefits in terms of target cell internalization and target tissue retention once the PNM has arrived at the target site. Increased understanding of the in vivo fate and interactions of the ligand-targeted PNMs with proteins and cells in the human body is mandatory to rationally advance the clinical translation of ligand-targeted PNMs. Future perspectives for ligand-targeted PNM approaches include the delivery of drugs that are unable or inefficient in passing cellular membranes, treatment of drug resistant tumors, targeting of the tumor blood supply, the generation of targeted vaccines and nanomedicines that are able to cross the blood-brain barrier.

  1. Modified Jeans instability of magnetized viscous spin 1/2 quantum plasma with resistive effects and Hall current

    NASA Astrophysics Data System (ADS)

    Sharma, Prerana; Chhajlani, R. K.

    2014-07-01

    The effect of Hall current on Jeans self-gravitational instability is examined for finitely conducting dense quantum viscous plasma in the presence of spin generated magnetization. The basic equations of the problem are constructed using quantum magneto hydrodynamic (QMHD) model. The Hall and resistivity terms are incorporated in the idealized Ohm's law and spin induced magnetization and viscosity terms are incorporated to the momentum equations. The general dispersion relation is found to be modified due to the presence of Hall current, electrical resistivity and viscosity parameter along with the spin induced magnetization. The dispersion relation is further reduced for both transverse and longitudinal mode of propagations. In the transverse mode of propagation the Jeans condition of instability is modified due to Alfven velocity, magnetization parameter and quantum corrections, and the growth rate of instability is found to be modified due to the electrical resistivity, viscosity, magnetization parameter and quantum corrections but remains unaffected by the presence of Hall current. In longitudinal direction of propagation the gravitational mode is affected due to the viscosity and quantum parameter while the Jeans condition of instability depends only upon the quantum correction. The Alfven mode in longitudinal direction gets modified due to the electrical resistivity, Hall current, viscosity and magnetization parameter however, it is found to be independent of quantum corrections. The numerical observations are also presented to show the effect of electrical resistivity, magnetization and quantum corrections on the growth rate of instability.

  2. Evaluation of current visualization tools for cyber security

    NASA Astrophysics Data System (ADS)

    Langton, John T.; Newey, Brent

    2010-04-01

    Visualization tools for cyber security often overlook related research from the information visualization domain. Cyber security data sets are notoriously large, yet many of the popular analysis tools use 3D techniques and parallel coordinates which have been shown to suffer issues of occlusion when applied to large data sets1,2. While techniques exist to ameliorate these issues they are typically not used. In this paper we evaluate several cyber security visualization tools based on established design principles and human-computer interaction research. We conclude by enumerating challenges, requirements, and recommendations for future work.

  3. Metallurgical Effects of Shunting Current on Resistance Spot-Welded Joints of AA2219 Sheets

    NASA Astrophysics Data System (ADS)

    Jafari Vardanjani, M.; Araee, A.; Senkara, J.; Jakubowski, J.; Godek, J.

    2016-08-01

    Shunting effect is the loss of electrical current via the secondary circuit provided due to the existence of previous nugget in a series of welding spots. This phenomenon influences on metallurgical aspects of resistance spot-welded (RSW) joints in terms of quality and performance. In this paper RSW joints of AA2219 sheets with 1 mm thickness are investigated metallurgically for shunted and single spots. An electro-thermal finite element analysis is performed on the RSW process of shunted spot and temperature distribution and variation are obtained. These predictions are then compared with experimental micrographs. Three values of 5 mm, 20 mm, and infinite (i.e., single spot) are assumed for welding distance. Numerical and experimental results are matching each other in terms of nugget and HAZ geometry as increasing distance raised nugget size and symmetry of HAZ. In addition, important effect of shunting current on nugget thickness, microstructure, and Copper segregation on HAZ grain boundaries were discovered. A quantitative analysis is also performed about the influence of welding distance on important properties including ratio of nugget thickness and diameter ( r t), ratio of HAZ area on shunted and free side of nugget ( r HA), and ratio of equivalent segregated and total amount of Copper, measured in sample ( r Cu) on HAZ. Increasing distance from 5 mm to infinite, indicated a gain of 111.04, -45.55, and -75.15% in r t, r HA, and r Cu, respectively, while obtained ratios for 20 mm welding distance was suitable compared to single spot.

  4. Evaluation of advanced and current leak detection system

    SciTech Connect

    Kupperman, D.S.

    1987-01-01

    US Nuclear Regulatory Commission Guide 1.45 recommends the use of at least three different detection methods in reactors to detect leakage. Monitoring of both sump-flow and airborne particulate radioactivity is mandatory. A third method can involve either monitoring of condensate flow rate from air coolers or monitoring of airborne gaseous radioactivity. Although the methods currently used for leak detection reflect the state of the art, other techniques may be developed and used. Since the recommendations of Regulatory Guide 1.45 are not mandatory, Licensee Event Report Compilations have been reviewed to help establish actual capabilities for leak detection. The review of reports which had previously covered the period June 1985 to August 1986, has been extended. The total number of events of significance is now 83. These reports have provided documented, sometimes detailed summaries of reactor leaks.

  5. Economic evaluation guidelines in Latin America: a current snapshot.

    PubMed

    Augustovski, Federico; Garay, Osvaldo Ulises; Pichon-Riviere, Andres; Rubinstein, Adolfo; Caporale, Joaquín E

    2010-10-01

    Economic evaluation guidelines are widespread in developed countries with fourth hurdle systems but as of yet not in Latin America. In the present article, a systematic search was conducted in order to retrieve regional guidelines in PubMed, Latin American and Caribbean Health Sciences Literature (LILACS) and the gray literature. Four national guidelines were found: Brazil, Colombia, Cuba and Mexico. We report a thorough review of these documents, as well as a comparison among them. We conclude that, despite some differences found, they are broadly similar, and are broadly in accordance with international documents. The existence of these documents, together with other experiences in the region that explicitly use economic evaluation information for health decision making clearly shows that this global tendency is gaining momentum in Latin America, although there is still a long way to go. In the near future we will be able to see if these documents were successfully used and applied for transparent and evidence-based decision making.

  6. A crossbar resistance switching memory readout scheme with sneak current cancellation based on a two-port current-mode sensing.

    PubMed

    Bae, Woorham; Yoon, Kyung Jean; Hwang, Cheol Seong; Jeong, Deog-Kyoon

    2016-12-02

    This paper describes a novel readout scheme that enables the complete cancellation of sneak currents in resistive switching random-access memory (RRAM) crossbar array. The current-mode readout is employed in the proposed readout, and a few critical advantages of the current-mode readout for crossbar RRAM are elucidated in this paper. The proposed scheme is based on a floating readout scheme for low power consumption, and one more sensing port is introduced using an additional reference word line. From the additional port, information on the sneak current amount is collected, and simple current-mode arithmetic operations are implemented to cancel out the sneak current from the sensing current. In addition, a simple method of handling the overestimated-sneak-current issue is described. The proposed scheme is verified using HSPICE simulation. Moreover, an example of a current-mode sense amplifier realizing the proposed cancelling technique is presented. The proposed sense amplifier can be implemented with less hardware overhead compared to the previous works.

  7. A crossbar resistance switching memory readout scheme with sneak current cancellation based on a two-port current-mode sensing

    NASA Astrophysics Data System (ADS)

    Bae, Woorham; Yoon, Kyung Jean; Hwang, Cheol Seong; Jeong, Deog-Kyoon

    2016-12-01

    This paper describes a novel readout scheme that enables the complete cancellation of sneak currents in resistive switching random-access memory (RRAM) crossbar array. The current-mode readout is employed in the proposed readout, and a few critical advantages of the current-mode readout for crossbar RRAM are elucidated in this paper. The proposed scheme is based on a floating readout scheme for low power consumption, and one more sensing port is introduced using an additional reference word line. From the additional port, information on the sneak current amount is collected, and simple current-mode arithmetic operations are implemented to cancel out the sneak current from the sensing current. In addition, a simple method of handling the overestimated-sneak-current issue is described. The proposed scheme is verified using HSPICE simulation. Moreover, an example of a current-mode sense amplifier realizing the proposed cancelling technique is presented. The proposed sense amplifier can be implemented with less hardware overhead compared to the previous works.

  8. Evaluation of Erosion Resistance of Advanced Turbine Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Zhu, Dongming; Kuczmarski, Maria A.; Miller, Robert A.; Cuy, Michael D.

    2007-01-01

    The erosion resistant turbine thermal barrier coating system is critical to aircraft engine performance and durability. By demonstrating advanced turbine material testing capabilities, we will be able to facilitate the critical turbine coating and subcomponent development and help establish advanced erosion-resistant turbine airfoil thermal barrier coatings design tools. The objective of this work is to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and/or thermal gradient environments, validating advanced turbine airfoil thermal barrier coating systems based on nano-tetragonal phase toughening design approaches.

  9. Measuring direct current trans-epithelial electrical resistance in organ-on-a-chip microsystems.

    PubMed

    Odijk, Mathieu; van der Meer, Andries D; Levner, Daniel; Kim, Hyun Jung; van der Helm, Marinke W; Segerink, Loes I; Frimat, Jean-Phillipe; Hamilton, Geraldine A; Ingber, Donald E; van den Berg, Albert

    2015-02-07

    Trans-epithelial electrical resistance (TEER) measurements are widely used as real-time, non-destructive, and label-free measurements of epithelial and endothelial barrier function. TEER measurements are ideal for characterizing tissue barrier function in organs-on-chip studies for drug testing and investigation of human disease models; however, published reports using this technique have reported highly conflicting results even with identical cell lines and experimental setups. The differences are even more dramatic when comparing measurements in conventional Transwell systems with those obtained in microfluidic systems. Our goal in this work was therefore to enhance the fidelity of TEER measurements in microfluidic organs-on-chips, specifically using direct current (DC) measurements of TEER, as this is the most widely used method reported in the literature. Here we present a mathematical model that accounts for differences measured in TEER between microfluidic chips and Transwell systems, which arise from differences in device geometry. The model is validated by comparing TEER measurements obtained in a microfluidic gut-on-a-chip device versus in a Transwell culture system. Moreover, we show that even small gaps in cell coverage (e.g., 0.4%) are sufficient to cause a significant (~80%) drop in TEER. Importantly, these findings demonstrate that TEER measurements obtained in microfluidic systems, such as organs-on-chips, require special consideration, specifically when results are to be compared with measurements obtained from Transwell systems.

  10. [Medicinal plants in cancer patients: current practices and evaluation data].

    PubMed

    Huet, Matthieu

    2013-05-01

    Many complementary and alternatives medicines are offered to patients with cancer. Among them, herbal medicines have a substantial place. These plants are mainly used to reduce adverse effects of anticancer treatments and for specific anticancer properties. Our review shows that only few clinical data support medicinal plants effectiveness in cancer patients. Arguments rely mainly on usual indications and pharmacological data for minimization of treatments toxicity while for the anticancer properties, on epidemiological and preclinical data. To inform and counsel patients and people around, healthcare professionals need to evaluate benefit-risk balance on evidence-based information. Because the medical decision should be shared with the patient, his beliefs and preferences have to be considered. When no adverse effect or drug interaction is associated with herbal medicine, we state that their use is acceptable. This paper discuss of potential risk and benefit of the most used medicinal plants by cancer patients.

  11. A Description and Evaluation of Current Practices of the Bartholomew Consolidated School Corporation Columbus Teacher Center.

    ERIC Educational Resources Information Center

    Henderson, Carl; And Others

    This report contains the observations made by a trio of external evaluators who conducted an on-site evaluation of the Columbus Teacher Center. A wide range of educational evaluation areas were explored. The report represents a description of current practices, strengths, concerns, and recommendations as viewed by the evaluation team. Educational…

  12. Effect of the surface film electric resistance on eddy current detectability of surface cracks in Alloy 600 tubes

    SciTech Connect

    Saario, T.; Paine, J.P.N.

    1995-12-31

    The most widely used technique for NDE of steam generator tubing is eddy current. This technique can reliably detect cracks grown in sodium hydroxide environment only at depths greater than 50% through wall. However, cracking caused by thiosulphate solutions have been detected and sized at shallower depths. The disparity has been proposed to be caused by the different electric resistance of the crack wall surface films and corrosion products in the cracks formed in different environments. This work was undertaken to clarify the role of surface film electric resistance on the disparity found in eddy current detectability of surface cracks in alloy 600 tubes. The proposed model explaining the above mentioned disparity is the following. The detectability of tightly closed cracks by the eddy current technique depends on the electric resistance of the surface films of the crack walls. The nature and resistance of the films which form on the crack walls during operation depends on the composition of the solution inside the crack and close to the crack location. During cooling down of the steam generator, because of contraction and loss of internal pressurization, the cracks are rather tightly closed so that exchange of electrolyte and thus changes in the film properties become difficult. As a result, the surface condition prevailing at high temperature is preserved. If the environment is such that the films formed on the crack walls under operating conditions have low electric resistance, eddy current technique will fail to indicate these cracks or will underestimate the size of these cracks. However, if the electric resistance of the films is high, a tightly closed crack will resemble an open crack and will be easily indicated and correctly sized by eddy current technique.

  13. Current concepts in antimicrobial therapy against select gram-positive organisms: methicillin-resistant Staphylococcus aureus, penicillin-resistant pneumococci, and vancomycin-resistant enterococci.

    PubMed

    Rivera, Ana Maria; Boucher, Helen W

    2011-12-01

    Gram-positive bacteria cause a broad spectrum of disease in immunocompetent and immunocompromised hosts. Despite increasing knowledge about resistance transmission patterns and new antibiotics, these organisms continue to cause significant morbidity and mortality, especially in the health care setting. Methicillin-resistant Staphylococcus aureus poses major problems worldwide as a cause of nosocomial infection and has emerged as a cause of community-acquired infections. This change in epidemiology affects choices of empirical antibiotics for skin and skin-structure infections and community-acquired pneumonia in many settings. Throughout the world, the treatment of community-acquired pneumonia and other respiratory tract infections caused by penicillin-resistant Streptococcus pneumoniae has been complicated by resistance to β-lactam and macrolide antibacterial drugs. Vancomycin-resistant enterococci are a major cause of infection in the hospital setting and remain resistant to treatment with most standard antibiotics. Treatment of diseases caused by resistant gram-positive bacteria requires appropriate use of available antibiotics and stewardship to prolong their effectiveness. In addition, appropriate and aggressive infection control efforts are vital to help prevent the spread of resistant pathogens.

  14. Control of antibiotic resistance in China must not be delayed: The current state of resistance and policy suggestions for the government, medical facilities, and patients.

    PubMed

    Tang, Qi; Song, Peipei; Li, Jiajia; Kong, Fanlei; Sun, Long; Xu, Lingzhong

    2016-02-01

    Antibiotics are medicines used to prevent and treat bacterial infections. Antibiotic resistance occurs when bacteria change in response to the use of these medicines. Antibiotic resistance is rising to dangerously high levels in all parts of the world, leading to higher medical costs, prolonged hospital stays, and increased mortality. In the European Union alone, drug-resistant bacteria are estimated to cause 25,000 deaths and cost more than US$1.5 billion every year in healthcare expenses and productivity losses. The problems of antibiotic misuse and antibiotic resistance are quite serious in China. In 2015, results of a study by the State Key Laboratory of Organic Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences indicated that the total antibiotic usage in China in 2013 was approximately 162,000 tons, including human use (48%) and use in animals (52%). This amount accounted for about half of the antibiotic usage worldwide. The per-capita use of antibiotics in China is more than 5 times that in Europe and the United States. These data mean that China is one of the world's leading countries with serious problems in terms of antibiotic misuse and antibiotic resistance. The current article analyzes the current state and harms of antibiotic misuse and causes of antibiotic resistance in China. The Government needs to pay close attention to the issue of antibiotic resistance in China and formulate a strategy at the national level. Thus, the following suggestions are offered: i) The Chinese Government should implement policies that promote antibiotic research and development; ii) Medical facilities in China should create multidisciplinary teams (MDTs) and encourage early action by MDTs to control the spread of multi-drug-resistant bacteria (MDRB); iii) An intervention in the form of health education should target patients and accompanying family members (AFM) in China. In other words, antibiotic resistance is not a personal problem but an

  15. Case study on the evaluation of the ground reinforcement with complex resistivity method

    NASA Astrophysics Data System (ADS)

    Son, J.; Kim, J.; Park, S.

    2008-12-01

    Recently complex resistivity (CR) method is applied to the various engineering purpose mainly due to the development of measurement instruments, which enables the detection of small IP effect in the subsurface. CR method is one of frequency-domain IP method, and it measures the amplitude and absolute phase with respect to the transmitted current. It is known as a spectral IP (SIP) method. With the recent development of instrument, the modeling and analysis algorithm for the CR method were already developed and nearly completed. In this study, we applied CR method to characterize the effect of ground reinforcement which uses grouting with the injection of cement mortar material. As curing the injected cement mortar, the electric conductivity changes, and average conductivity of it is very high. Because of it, we used the DC resistivity monitoring as the way of evaluating the grouting performance. In addition to this, we applied the CR method after that the ground reinforcement with grouting was completed because we thought that cement mortar may show a strong IP effect. For the DC monitoring, we acquired the surface resistivity data before, during and after grouting. Total six data sets were acquired and processed with the recently developed 4D inversion algorithm. CR data is also processed with the developed two-dimensional inversion algorithm and then inverted sections from CR method were compared to the results of DC monitoring data. The area which was identified by 4D DC monitoring as the region where the cement mortar was injected and infiltrated were well matched the anomalous area shown in the phase section of CR method. Resistivity change was not clear with the injection of cement mortar, but phase change was clearly noticeable in the inverted section. From this, we hoped that CR method could provide a way of the quantitative estimation of ground improvement.

  16. Current density and catalyst-coated membrane resistance distribution of hydro-formed metallic bipolar plate fuel cell short stack with 250 cm2 active area

    NASA Astrophysics Data System (ADS)

    Haase, S.; Moser, M.; Hirschfeld, J. A.; Jozwiak, K.

    2016-01-01

    An automotive fuel cell with an active area of 250 cm2 is investigated in a 4-cell short stack with a current and temperature distribution device next to the bipolar plate with 560 current and 140 temperature segments. The electrical conductivities of the bipolar plate and gas diffusion layer assembly are determined ex-situ with this current scan shunt module. The applied fuel cell consists of bipolar plates constructed of 75-μm-thick, welded stainless-steel foils and a graphitic coating. The electrical conductivities of the bipolar plate and gas diffusion layer assembly are determined ex-situ with this module with a 6% deviation in in-plane conductivity. The current density distribution is evaluated up to 2.4 A cm-2. The entire cell's investigated volumetric power density is 4.7 kW l-1, and its gravimetric power density is 4.3 kW kg-1 at an average cell voltage of 0.5 V. The current density distribution is determined without influencing the operating cell. In addition, the current density distribution in the catalyst-coated membrane and its effective resistivity distribution with a finite volume discretisation of Ohm's law are evaluated. The deviation between the current density distributions in the catalyst-coated membrane and the bipolar plate is determined.

  17. Evaluation of Deep Subsurface Resistivity Imaging for Hydrofracture Monitoring

    SciTech Connect

    Hibbs, Andrew; Wilt, Michael

    2016-09-28

    This report describes the results of the first of its kind monitoring of a hydrofracture operation with electromagnetic measurements. The researchers teamed with oil and gas producer Encana Corporation to design and execute a borehole to surface monitoring of three fracture stages at a well pad in central Colorado. The field project consisted of an equipment upgrade, a survey design and modeling phase, several weeks of data collection, and data processing and interpretation. Existing Depth to Surface Resistivity (DSR) instrumentation was upgraded to allow for continuous high precision recording from downhole sources. The full system can now collect data continuously for up to 72 hours, which is sufficient to measure data for 10 frac stages. Next we used numerical modeling and frac treatment data supplied by Encana to design a field survey to detect EM signal from induced fractures. Prior to modeling we developed a novel technique for using well casing as an antenna for a downhole source. Modeling shows that 1) a measurable response for an induced fracture could be achieved if the facture fluid was of high salinity 2) an optimum fracture response is created when the primary source field is parallel to the well casing but perpendicular to the fracture direction. In mid-July, 2014 we installed an array of more than 100 surface sensors, distributed above the treatment wells and extending for approximately 1 km north and 750 m eastward. We applied a 0.6 Hz square wave signal to a downhole current electrode located in a horizontal well 200 m offset from the treatment well with a return electrode on the surface. The data were transmitted to a recording trailer via Wi-Fi where we monitored receiver and transmitter channels continuously in a 72-hour period which covered 7 frac stages, three of which were high salinity. Although the background conditions were very noisy we were able to extract a clear signal from the high salinity stages. Initial data interpretation attempts

  18. Current status of decay heat measurements, evaluations, and needs

    SciTech Connect

    Dickens, J.K.

    1986-07-01

    Over a decade ago serious concern over possible consequences of a loss-of-coolant accident in a commercial light-water reactor prompted support of several experiments designed specifically to measure the latent energy of beta-ray and gamma-ray emanations from fission products for thermal reactors. This latent energy was termed Decay Heat. At about the same time the American Nuclear Society convened a working group to develop a standard for use in computing decay heat in real reactor environs primarily for regulatory requirements. This working group combined the new experimental results and best evaluated data into a standard which was approved by the ANS and by the ANSI. The primary work since then has been: (a) on improvements to computational efforts and (b) experimental measurements for fast reactors. In addition, the need for decay-heat data has been extended well beyond the time regime of a loss-of-coolant accident; new concerns involve, for example, away-from-reactor shipments and storage. The efficacy of the ANS standard for these longer time regimes has been a subject of study with generally positive results. However, a specific problem, namely, the consequences of fission-product neutron capture, remains contentious. Satisfactory resolution of this problem merits a high priority. 31 refs., 4 figs., 1 tab.

  19. [Methods and current significance of the evaluation of microscopic haematuria].

    PubMed

    Hüppe, P; Wawroschek, F

    2011-03-01

    Haematuria is the main symptom of malignant diseases of the urinary tract. Hence urine analysis for the detection of microscopic haematuria is an accepted diagnostic procedure in daily urologic practice. Until now there are neither international nor national agreements relating to the definition of microscopic haematuria, the choice of verification procedures and a diagnostic algorithm. As there are diverse reasons for microscopic haematuria the extent of continuative diagnostics should be adapted to the existence of risk factors for a clinically apparent disease. Low-risk patients with asymptomatic microscopic haematuria do not necessarily have to undergo primary cystoscopy if there are no pathological findings on urine cytology or ultrasound examination. Microhaematuria in high-risk patients should lead to a more intensive evaluation of the urinary tract, which should include cystoscopy and imaging of the upper urinary tract. In the diagnostics of microhaematuria you have to be aware of that intermittent bleeding is often characteristic of urothelial malignancies. Therefore, a single negative urine analysis should not lead to abandonment of further diagnostic procedures.

  20. Evaluation of alternative tactics for management of insecticide-resistant horn flies (Diptera: Muscidae).

    PubMed

    Steelman, C D; McNew, R W; Simpson, R B; Rorie, R W; Phillips, J M; Rosenkrans, C F

    2003-06-01

    A 3-yr study was conducted to determine the efficacy of tactics that could be used to manage populations of insecticide-resistant horn flies, Hematobia irritans irritans (L.). Insecticide spray, spot-on or pour-on formulations and two IGRs in bolus formulation, 1.3- and 3.2-ha pasture rotations on different rotation schedules, 0-50% Brahman breeding, selected fly-resistant cows, and a mechanical trap were evaluated singly and in combination. Concentration-mortality tests indicated that horn flies collected from cows used in the current study were significantly less susceptible to diazinon, coumaphos, and methoxychlor than horn flies from cows at the same locations previously used to determine baseline susceptibility. During the 3-yr study at the Southeast Research and Extension Center (SEREC), the IGR-bolus significantly reduced (P < 0.05) horn fly numbers on both the continuous and rotational graze regimens, resulting in significantly (P < 0.05) greater calf weaning weights (average of 24 kg). Horn fly numbers were significantly greater on untreated cows during the 3-yr study at the Southwest Research and Extension Center (SWREC) compared with the mean fly numbers on cows that received fly-management treatments. All tactics and tactic-combinations used at SWREC on cattle having no Brahman breeding failed to significantly reduce insecticide-resistant horn fly numbers. However, the combination of Brahman breeding with the IGR-Bolus and mechanical trap significantly reduced horn fly numbers and resulted in significant increases in calf weaning weight. In addition, mean horn fly numbers decreased significantly as the percentage Brahman breeding increased with 50% Brahman breeding reducing horn fly numbers by 140 flies per cow. No significant difference was found between the mean fly numbers on the fly-resistant purebred group and the cows that had no Brahman breeding but received the IGR-Bolus or used the mechanical trap. The use of synergized zeta-cypermethrin pour

  1. Evaluating current trends in psychiatric music therapy: a descriptive analysis.

    PubMed

    Silverman, Michael J

    2007-01-01

    Approximately 21% of music therapists report working in the mental health field, more so than another other specific client population category (AMTA, 2005). The purpose of this study was to descriptively evaluate psychiatric music therapists and their institutions, philosophies, interventions, and clinical objectives. A survey was designed and posted online or mailed to music therapists who did not have email addresses in the 2005 Member Sourcebook (AMTA, 2005). A total of 176 psychiatric music therapists completed various parts of the survey for an overall response rate of 42.9%. Respondents reported working a mean of 11.3 years in the psychiatric setting, being Board-Certified Music Therapists for 13.3 years, and working at their institution for 8.4 years. Most respondents (90.6%) indicated they did not have a music therapist as a supervisor. Group music therapy was the dominant modality in psychiatric institutions for music therapists. Respondents indicated they read music therapy journals (80%) and other types of psychiatric periodicals (57.1%), presented educational sessions at conferences (44.6%), conducted in-services for hospital staff (64.8%), worked with an interdisciplinary treatment team (77.9%), and trained practica students (43.5%) and interns (37.4%). Respondents also indicated that although most were not bilingual (85.7%), they still worked with non-English speaking consumers (58.2%). Participants noted that they enjoyed working with the psychiatric population and felt they had a positive influence on treatment as indicated by Likert-type scales. Respondents reported using primarily behavioral or psychodynamic approaches but considered their primary psychological philosophy as eclectic. Participants predominantly indicated they addressed goal areas such as socialization, communication, self-esteem, coping skills, and stress reduction/management. Participants noted they employed a variety of music therapy techniques such as music assisted relaxation

  2. The 12th I. E. Melhus Graduate Student Symposium: host plant resistance and disease management, current status and future outlook

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The 12th I. E. Melhus Graduate Student Symposium was held on 6 August 2012 during the Annual meeting of the American Phytopathological Society (APS) in Providence, RI. The theme for this symposium was “Host Plant Resistance and Disease Management: Current Status and Future Outlook”. The APS Host R...

  3. Improving Students' Ability to Intuitively Infer Resistance from Magnitude of Current and Potential Difference Information: A Functional Learning Approach

    ERIC Educational Resources Information Center

    Chasseigne, Gerard; Giraudeau, Caroline; Lafon, Peggy; Mullet, Etienne

    2011-01-01

    The study examined the knowledge of the functional relations between potential difference, magnitude of current, and resistance among seventh graders, ninth graders, 11th graders (in technical schools), and college students. It also tested the efficiency of a learning device named "functional learning" derived from cognitive psychology on the…

  4. Evaluation of Fluoromycobacteriophages for Detecting Drug Resistance in Mycobacterium tuberculosis▿

    PubMed Central

    Rondón, Liliana; Piuri, Mariana; Jacobs, William R.; de Waard, Jacobus; Hatfull, Graham F.; Takiff, Howard E.

    2011-01-01

    We tested a new method for detecting drug-resistant strains of Mycobacterium tuberculosis that uses a TM4 mycobacteriophage phAE87::hsp60-EGFP (EGFP-phage) engineered to contain the gene encoding enhanced green fluorescent protein (EGFP). After promising results in preliminary studies, the EGFP-phage was used to detect isoniazid (INH), rifampin (RIF), and streptomycin (STR) resistance in 155 strains of M. tuberculosis, and the results were compared to the resazurin microplate technique, with the proportion method serving as the reference standard. The resazurin technique yielded sensitivities of 94% for INH and RIF and 98% for STR and specificities of 97% for INH, 95% for RIF, and 98% for STR. The sensitivity of EGFP-phage was 94% for all three antibiotics, with specificities of 90% for INH, 93% for RIF, and 95% for STR. The EGFP-phage results were available in 2 days for RIF and STR and in 3 days for INH, with an estimated cost of ∼2$ to test the three antibiotics. Using a more stringent criterion for resistance improved the specificity of the EGFP-phage for INH and RIF without affecting the sensitivity. In preliminary studies, the EGFP-phage could also effectively detect resistance to the fluoroquinolones. The EGFP-phage method has the potential to be a valuable rapid and economic screen for detecting drug-resistant tuberculosis if the procedure can be simplified, if it can be adapted to clinical material, and if its sensitivity can be improved. PMID:21346042

  5. Evaluation of Heat Checking and Washout of Heat Resistant Superalloys and Coatings for Die inserts

    SciTech Connect

    David Schwam; John F. Wallace; Yulong Zhu; Edward Courtright; Harold Adkins

    2005-01-30

    This project had two main objectives: (1) To design, fabricate and run a full size test for evaluating soldering and washout in die insert materials. This test utilizes the unique capabilities of the 350 Ton Squeeze Casting machine available in the Case Meal Casting Laboratory. Apply the test to evaluate resistance of die materials and coating, including heat resistant alloys to soldering and washout damage. (2) To evaluate materials and coatings, including heat resistant superalloys, for use as inserts in die casting of aluminum alloys.

  6. A Randomized Double-Blind Sham-Controlled Study of Transcranial Direct Current Stimulation for Treatment-Resistant Major Depression

    PubMed Central

    Blumberger, Daniel M.; Tran, Lisa C.; Fitzgerald, Paul B.; Hoy, Kate E.; Daskalakis, Zafiris J.

    2012-01-01

    Objectives: Transcranial direct current stimulation (tDCS) has demonstrated some efficacy in treatment-resistant major depression (TRD). The majority of previous controlled studies have used anodal stimulation to the left dorsolateral prefrontal cortex (DLPFC) and a control location such as the supraorbital region for the cathode. Several open-label studies have suggested effectiveness from anodal stimulation to the left DLPFC combined with cathodal stimulation to the right DLPFC. Thus, this study evaluated the efficacy of tDCS using anodal stimulation to the left DLPFC and cathodal stimulation to the right DLPFC compared to sham tDCS. Methods: Subjects between the ages of 18 and 65 were recruited from a tertiary care university hospital. Twenty-four subjects with TRD and a 17-item Hamilton Rating Scale for Depression greater than 21 were randomized to receive tDCS or sham tDCS. The rates of remission were compared between the two treatment groups. Results: The remission rates did not differ significantly between the two groups using an intention to treat analysis. More subjects in the active tDCS group had failed a course of electroconvulsive therapy in the current depressive episode. Side effects did not differ between the two groups and in general the treatment was very well tolerated. Conclusion: Anodal stimulation to the left DLPFC and cathodal stimulation to the right DLPFC was not efficacious in TRD. However, a number of methodological limitations warrant caution in generalizing from this study. Ongoing, controlled studies should provide further clarification on the efficacy of this stimulation configuration in TRD. ClinicalTrials.gov Identifier: NCT01078948. PMID:22912618

  7. Evaluation of the damages caused by lightning current flowing through bearings

    NASA Technical Reports Server (NTRS)

    Celi, O.; Pigini, A.; Garbagnati, E.

    1991-01-01

    A laboratory for lightning current tests was set up allowing the generation of the lightning currents foreseen by the Standards. Lightning tests are carried out on different objects, aircraft materials and components, evaluating the direct and indirect effects of lightning. Recently a research was carried out to evaluate the effects of the lightning current flow through bearings with special reference to wind power generator applications. For this purpose, lightning currents of different amplitude were applied to bearings in different test conditions and the damages caused by the lightning current flow were analyzed. The influence of the load acting on the bearing, the presence of lubricant and the bearing rotation were studied.

  8. Direct-current resistivity profiling at the Pecos River Ecosystem Project study site near Mentone, Texas, 2006

    USGS Publications Warehouse

    Teeple, Andrew; McDonald, Alyson K.; Payne, Jason; Kress, Wade H.

    2009-01-01

    The U.S. Geological Survey, in cooperation with Texas A&M University AgriLife, did a surface geophysical investigation at the Pecos River Ecosystem Project study site near Mentone in West Texas intended to determine shallow (to about 14 meters below the water [river] surface) subsurface composition (lithology) in and near treated (eradicated of all saltcedar) and control (untreated) riparian zone sites during June-August 2006. Land-based direct-current resistivity profiling was applied in a 240-meter section of the riverbank at the control site, and waterborne direct-current continuous resistivity profiling (CRP) was applied along a 2.279-kilometer reach of the river adjacent to both sites to collect shallow subsurface resistivity data. Inverse modeling was used to obtain a nonunique estimate of the true subsurface resistivity from apparent resistivity calculated from the field measurements. The land-based survey showed that the sub-surface at the control site generally is of relatively low resis-tivity down to about 4 meters below the water surface. Most of the section from about 4 to 10 meters below the water surface is of relatively high resistivity. The waterborne CRP surveys convey essentially the same electrical representation of the lithology at the control site to 10 meters below the water surface; but the CRP surveys show considerably lower resistivity than the land-based survey in the subsection from about 4 to 10 meters below the water surface. The CRP surveys along the 2.279-kilometer reach of the river adjacent to both the treated and control sites show the same relatively low resistivity zone from the riverbed to about 4 meters below the water surface evident at the control site. A slightly higher resistivity zone is observed from about 4 to 14 meters below the water surface along the upstream approximately one-half of the profile than along the downstream one-half. The variations in resistivity could not be matched to variations in lithology because

  9. Evaluating antibiotic resistance genes in soils with applied manures

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Antibiotics are commonly used in livestock production to promote growth and combat disease. Recent studies have shown the potential for spread of antibiotic resistance genes (ARG) to the environment following application of livestock manures. In this study, concentrations of bacteria with ARG in soi...

  10. Evaluating Technology Resistance and Technology Satisfaction on Students' Performance

    ERIC Educational Resources Information Center

    Norzaidi, Mohd Daud; Salwani, Mohamed Intan

    2009-01-01

    Purpose: Using the extended task-technology fit (TTF) model, this paper aims to examine technology resistance, technology satisfaction and internet usage on students' performance. Design/methodology/approach: The study was conducted at Universiti Teknologi MARA, Johor, Malaysia and questionnaires were distributed to 354 undergraduate students.…

  11. Standardized Plant Disease Evaluations will Enhance Resistance Gene Discovery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gene discovery and marker development using DNA based tools require plant populations with well-documented phenotypes. Related crops such as apples and pears may share a number of genes, for example resistance to common diseases, and data mining in one crop may reveal genes for the other. However, u...

  12. Evaluation of wild juglans species for crown gall resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    During the 2009 USDA, ARS, National Clonal Germplasm Repository (NCGR) germplasm screening season, we examined a total of ~300 seedlings from "new" genotypes for their resistance to A. tumefaciens. This consisted of seedlings from 89 mother trees representing J. regia and its conspecific taxon, J. s...

  13. Evaluation of soybean genotypes for resistance to charcoal rot

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Charcoal rot caused by Macrophomina phaseolina causes more yield loss in soybean than most other diseases in the southern U.S.A. There are no commercial genotypes marketed as resistant to charcoal rot of soybean. Reactions of 27 maturity group (MG) III, 29 Early MG IV, 34 Late MG IV, and 59 MG V gen...

  14. Test and Evaluation of Four Fire Resistant Booms at OHMSETT

    DTIC Science & Technology

    1999-08-01

    steel Proprietary Stainless steel Resistant Material information (SS) woven blend of Inconel® and Fiberfrax ® Tension Member 3/8" Galvanized Stainless...material ( Fiberfrax ) which was severely damaged during the bum tests. In terms of percentages, and relative to baseline loss speeds, The first wave

  15. Long term field evaluation reveals HLB resistance in Citrus relatives

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Citrus huanglongbing (HLB) is a destructive disease with no known cure. To identify sources of HLB resistance in the subfamily Aurantioideae to which citrus belongs, we conducted a six-year field trial under natural disease challenge conditions in an HLB endemic region. The study included 65 Citrus ...

  16. Evaluating paradox walnut rootstocks for resistance to Armillaria root disease

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The most common Juglans regia (English walnut) rootstock in California is Paradox, a hybrid between J. hindsii (Northern California black walnut) and J. regia. Unfortuntely, Paradox rootstock is highly susceptible to Armillaria root disease. The relative resistance of new clonal, Paradox rootstock...

  17. Modeling and analysis of direct-current electrical resistivity in the Durham Triassic basin, North Carolina

    USGS Publications Warehouse

    Brown, C. Erwin

    1987-01-01

    Sixty-two Schlumberger electrical soundings were made in the Durham Triassic basin in an effort to determine basin structural geometry, depth of the sedimentary layers, and spatial distribution of individual rock facies. A digital computer program was used to invert the sounding curves of apparent resistivity versus distance to apparent resistivity versus depth. The apparent-resistivity-versus-depth data from the computer-modeling program were used to construct a geoelectric model of the basin that is believed to accurately represent the subsurface geology of the basin. The largest depth to basement in the basin along a resistivity profile (geoelectric section) was determined to be 1,800 m. A resistivity decrease was observed on certain soundings from depths of 100 to 1,000 m; below a 1,000-m depth, apparent resistivity increased to the bottom of the basin. Resistivity values for basement rocks were greater than 1,000 ohm-m and less than 350 ohm-m for the sedimentary layers in the basin. The data suggest that the basin contains a system of step faults near its eastern boundary. ?? 1987.

  18. Use of FAMACHA system to evaluate gastrointestinal nematode resistance/resilience in offspring of stud rams

    Technology Transfer Automated Retrieval System (TEKTRAN)

    High levels of anthelmintic resistance in gastrointestinal nematodes (GIN) of small ruminants have created the need for animals with greater resistance to these parasites. The objective of this experiment was to evaluate the effectiveness of the FAMACHA system in identification of parasite resilien...

  19. A relative resistance Ratio for Evaluation of Stem Borer Susceptibility Among Sugarcane Cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The Mexican rice borer, Eoreuma loftini (Dyar), is a major pest of sugarcane in Louisiana and Texas. Cultivar resistance to E. loftini was evaluated in commercial and experimental sugarcane cultivars in four replicated field studies between 2009 and 2012. A relative resistance ratio was developed t...

  20. A screening method for evaluating resistance to the spotted wing drosophilla (drosophilla suzukii)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The objective of the study was to develop an effective screening method for evaluating resistance to the Spotted Wing Drosophilla (SWD, and to locate resistance in southern adapted blueberry germplasm including the hexaploid rabbiteye (Vaccinium asheii Reade = V. virgatum Aiton) and the tetraploid s...

  1. Greenhouse and Field Evaluation of Multiple Virus Resistant Lagenaria siceraria Lines Potentially useful for Watermelon Rootstocks

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In previous evaluations we identified numerous lines of bottle gourd (Lagenaria siceraria) with complete or partial resistance to Zucchini yellow mosaic virus (ZYMV). In the present study, we were interested in developing bottle gourd lines with multiple virus resistance that could be useful as roo...

  2. A cut-stem inoculation technique to evaluate soybean for resistance to Macrophomina phaseolina

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Charcoal rot of soybean is caused by the fungal pathogen Macrophomina phaseolina. Effective and reliable methods to evaluate soybean for resistance to this fungus are needed as part of a management scheme that would utilize host resistance. This study investigated the use of a cut-stem inoculation t...

  3. Evaluation of dry-fleshed sweetpotato genotypes for resistance to soil insect pests, 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Two insect susceptible check cultivars (‘Beauregard” and ‘SC1149 19’), an insect resistant check cultivar (‘Ruddy’), 23 advanced dry-fleshed genotypes, and five dry-fleshed cultivars (‘Liberty’, ‘NC Japanese’, ‘Okinawa 100’, ‘Sumor’, and ‘Xushu-18’) were evaluated for insect resistance in replicate...

  4. Evaluation of dry-fleshed sweetpotato genotypes for resistance to soil insect pests, 2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    An insect susceptible check cultivar (‘SC1149 19’), an insect resistant check cultivar (‘Ruddy’), 20 advanced dry-fleshed genotypes, and five dry-fleshed cultivars (‘Bonita’, ‘Liberty’, ‘NC Japanese’, ‘Picadito’, and ‘Sumor’) were evaluated for insect resistance in replicated field trials at Charles...

  5. Influence of electrical current variance and thermal resistances on optimum working conditions and geometry for thermoelectric energy harvesting

    NASA Astrophysics Data System (ADS)

    Gomez, Miguel; Reid, Rachel; Ohara, Brandon; Lee, Hohyun

    2013-05-01

    Recent reports on enhanced thermoelectric figure of merits based on nanoscale effects have revived interest in potential applications of thermoelectric modules for waste heat recovery and distributed power generation. However, studies of optimized working conditions have not been thoroughly investigated. The majority of the previous studies on optimum load resistance for maximum power output or maximum efficiency assume temperatures at the ends of thermoelectric materials are known and constant. In reality, temperature should be determined by the energy conservation equations, which are functions of the load resistance, as well as the thermal resistances of the heat source, heat sink, and contact pads. This work exploits a numerical method to determine the actual temperature of thermoelectric materials, and optimum working conditions for thermoelectric energy harvesting are presented. The proposed model considers the effect of thermal resistances between a thermoelectric module and heat reservoirs, and the electrical current variation with respect to load resistance. The optimum condition for load resistance ratio was observed to occur at larger values than those obtained from traditional optimization work. Additionally, optimum geometry for a thermoelectric module is suggested for energy harvesting methods, where forced convection or oversized heat sinks cannot be used. Experimental results obtained from a commercial thermoelectric module are also presented to validate the proposed model. This work forms a basis to predict optimum working conditions in various thermoelectric energy harvesting applications.

  6. A Nondestructive Evaluation Method: Measuring the Fixed Strength of Spot-Welded Joint Points by Surface Electrical Resistivity.

    PubMed

    Shimamoto, Akira; Yamashita, Keitaro; Inoue, Hirofumi; Yang, Sung-Mo; Iwata, Masahiro; Ike, Natsuko

    2013-04-01

    Destructive tests are generally applied to evaluate the fixed strength of spot-welding nuggets of zinc-plated steel (which is a widely used primary structural material for automobiles). These destructive tests, however, are expensive and time-consuming. This paper proposes a nondestructive method for evaluating the fixed strength of the welded joints using surface electrical resistance. A direct current nugget-tester and probes have been developed by the authors for this purpose. The proposed nondestructive method uses the relative decrease in surface electrical resistance, α. The proposed method also considers the effect of the corona bond. The nugget diameter is estimated by two factors: RQuota, which is calculated from variation of resistance, and a constant that represents the area of the corona bond. Since the maximum tensile strength is correlated with the nugget diameter, it can be inferred from the estimated nugget diameter. When appropriate measuring conditions for the surface electrical resistance are chosen, the proposed method can effectively evaluate the fixed strength of the spot-welded joints even if the steel sheet is zinc-plated.

  7. One ring to rule them all: Current trends in combating bacterial resistance to the β‐lactams

    PubMed Central

    King, Dustin T.; Sobhanifar, Solmaz

    2016-01-01

    Abstract From humble beginnings of a contaminated petri dish, β‐lactam antibiotics have distinguished themselves among some of the most powerful drugs in human history. The devastating effects of antibiotic resistance have nevertheless led to an “arms race” with disquieting prospects. The emergence of multidrug resistant bacteria threatens an ever‐dwindling antibiotic arsenal, calling for new discovery, rediscovery, and innovation in β‐lactam research. Here the current state of β‐lactam antibiotics from a structural perspective was reviewed. PMID:26813250

  8. Evaluation of Glyphosate-Resistant Soybean Cultivars for Resistance to Bacterial Pustule

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Xanthomonas axonopodis pv. glycines causes bacterial pustule of soybean, which is a common disease in many soybean-growing areas of the world and is controlled by a single recessive gene that was commonly found in many conventional glyphosate-sensitive soybean cultivars. Since glyphosate-resistant c...

  9. On the Modeling of Electrical Effects Experienced by Space Explorers During Extra Vehicular Activities: Intracorporal Currents, Resistances, and Electric Fields

    NASA Technical Reports Server (NTRS)

    Cela, Carlos J.; Loizos, Kyle; Lazzi, Gianluca; Hamilton, Douglas; Lee, Raphael C.

    2011-01-01

    Recent research has shown that space explorers engaged in Extra Vehicular Activities (EVAs) may be exposed, under certain conditions, to undesired electrical currents. This work focuses on determining whether these undesired induced electrical currents could be responsible for involuntary neuromuscular activity in the subjects, possibly caused by either large diameter peripheral nerve activation or reflex activity from cutaneous afferent stimulation. An efficient multiresolution variant of the admittance method along with a millimeter-resolution model of a male human body were used to calculate induced electric fields, resistance between contact electrodes used to simulate the potential exposure condition, and currents induced in the human body model. Results show that, under realistic exposure conditions using a 15V source, current density magnitudes and total current injected are well above previously reported startle reaction thresholds. This indicates that, under the considered conditions, the subjects could experience involuntary motor response.

  10. Evaluation of antimalarial resistance marker polymorphism in returned migrant workers in China.

    PubMed

    Feng, Jun; Li, Jun; Yan, He; Feng, Xinyu; Xia, Zhigui

    2015-01-01

    Imported malaria has been a great challenge for public health in China due to decreased locally transmitted cases and frequent exchange worldwide. Plasmodium falciparum has been mainly responsible for the increasing impact. Currently, artesunate plus amodiaquine, one of the artemisinin combination therapies recommended by the World Health Organization, has been mainly used against uncomplicated P. falciparum malaria in China. However, drug resistance marker polymorphism in returning migrant workers has not been demonstrated. Here, we have evaluated the prevalence of pfmdr1 and pfcrt polymorphisms, as well as the K13 propeller gene, a molecular marker of artemisinin resistance, in migrant workers returned from Ghana to Shanglin County, Guangxi Province, China, in 2013. A total of 118 blood samples were randomly selected and used for the assay. Mutations of the pfmdr1 gene that covered codons 86, 184, 1034, and 1246 were found in 11 isolates. Mutations at codon N86Y (9.7%) were more frequent than at others, and Y(86)Y(184)S(1034)D(1246) was the most prevalent (63.6%) of the four haplotypes. Mutations of the pfcrt gene that covered codons 74, 75, and 76 were observed in 17 isolates, and M(74)N(75)T(76) was common (70.6%) in three haplotypes. Eight different genotypes of the K13 propeller were first observed in 10 samples in China, 2 synonymous mutations (V487V and A627A) and 6 nonsynonymous mutations. C580Y was the most prevalent (2.7%) in all the samples. The data presented might be helpful for enrichment of molecular surveillance of antimalarial resistance and will be useful for developing and updating antimalarial guidance in China.

  11. Mapping of the resistance of a superconducting transition edge sensor as a function of temperature, current, and applied magnetic field

    NASA Astrophysics Data System (ADS)

    Zhang, Shuo; Eckart, Megan E.; Jaeckel, Felix T.; Kripps, Kari L.; McCammon, Dan; Morgan, Kelsey M.; Zhou, Yu

    2017-02-01

    We have measured the resistance R ( T , I , B ext ) of a superconducting transition edge sensor over the entire transition region on a fine scale, producing a four-dimensional map of the resistance surface. The dimensionless temperature and current sensitivities ( α ≡ ∂ log R / ∂ log T | I and β ≡ ∂ log R / ∂ log I | T ) of the TES resistance have been determined at each point. α and β are closely related to the sensor performance, but show a great deal of complex, large amplitude fine structure over large portions of the surface that is sensitive to the applied magnetic field. We discuss the relation of this structure to the presence of Josephson "weak link" fringes.

  12. Rapid Detection of Bacterial Antibiotic Resistance: Preliminary Evaluation of PCR Assays Targeting Tetracycline Resistance Genes

    DTIC Science & Technology

    2007-08-01

    Molecular analysis of rifampin resistance in Bacillus anthracis and Bacillus cereus . Antimicrobial Agents and Chemotherapy 46: 511-513 15 DSTO-TR...fever. Infections like inhalation anthrax and pneumonic plague, caused by Bacillus anthracis and Yersinia pestis, have to be treated with an effective...Table 1. Antibiotics commonly used against diseases caused by potential BW agents Organism Disease Antibiotics Bacillus anthracis Anthrax Ciprofloxacin

  13. Engineering pathogen resistance in crop plants: current trends and future prospects.

    PubMed

    Collinge, David B; Jørgensen, Hans J L; Lund, Ole S; Lyngkjaer, Michael F

    2010-01-01

    Transgenic crops are now grown commercially in 25 countries worldwide. Although pathogens represent major constraints for the growth of many crops, only a tiny proportion of these transgenic crops carry disease resistance traits. Nevertheless, transgenic disease-resistant plants represent approximately 10% of the total number of approved field trials in North America, a proportion that has remained constant for 15 years. In this review, we explore the socioeconomic and biological reasons for the paradox that although technically useful solutions now exist for providing transgenic disease resistance, very few new crops have been introduced to the global market. For bacteria and fungi, the majority of transgenic crops in trials express antimicrobial proteins. For viruses, three-quarters of the transgenics express coat protein (CP) genes. There is a notable trend toward more biologically sophisticated solutions involving components of signal transduction pathways regulating plant defenses. For viruses, RNA interference is increasingly being used.

  14. Fire-resistant aircraft materials development and evaluation program

    NASA Technical Reports Server (NTRS)

    Bricker, R. W.; Stuckey, R. N.

    1974-01-01

    The overall objectives of this program are to provide a more fire-resistant commercial aircraft interior and to improve the fuselage insulation barrier between the cabin interior and an exterior fuel fire. Significant secondary objectives are to reduce the smoke and toxic gas production of the materials and to meet the end item use requirements pertaining to wearability, color fastness, and aesthetic appeal. It is shown that the fuselage insulation materials must meet stringent requirements pertaining to acoustic attenuation, low density, and water repellency.

  15. Use of a square-array direct-current resistivity method to detect fractures in crystalline bedrock in New Hampshire

    USGS Publications Warehouse

    Lane, J.W.; Haeni, F.P.; Watson, W.M.

    1995-01-01

    Azimuthal square-array direct-current (dc) resistivity soundings were used to detect fractures in bedrock in the Mirror Lake watershed in Grafton County, New Hampshire. Soundings were conducted at a site where crystalline bedrock underlies approximately 7 m (meters) of glacial drift. Measured apparent resistivities changed with the orientation of the array. Graphical interpretation of the square-array data indicates that a dominant fracture set and (or) foliation in the bedrock is oriented at 030° (degrees). Interpretation of crossed square-array data indicates an orientation of 027° and an anisotropy factor of 1.31. Assuming that anisotropy is due to fractures, the secondary porosity is estimated to range from 0.01 to 0.10.Interpretations of azimuthal square-array data are supported by other geophysical data, including azimuthal seismic-refraction surveys and azimuthal Schlumberger dc-resistivity soundings at the Camp Osceola well field. Dominant fracture trends indicated by these geophysical methods are 022° (seismic-refraction) and 037° (dc-resistivity). Fracture mapping of bedrock outcrops at a site within 250 m indicates that the maximum fracture-strike frequency is oriented at 030°.The square-array dc-resistivity sounding method is more sensitive to a given rock anisotropy than the more commonly used Schlumberger and Wenner arrays. An additional advantage of the square-array method is that it requires about 65 percent less surface area than an equivalent survey using a Schlumberger or Wenner array.

  16. Current role of community-acquired methicillin-resistant Staphylococcus aureus among children with skin and soft tissue infections.

    PubMed

    Teran, Carlos G; Sura, Sunitha; Mohamed, Tarek; Lin, Thant; Meadows, Marsha; Cynthia, Donkor; Wong, Sze H

    2012-01-02

    Community-acquired methicillin-resistant Staphylococcus aureus has become a well-established pathogen with alarming rates during the last decade. The current situation of this bacteria in pediatric infections is very limited and motivated us to conduct this study. This is a retrospective and analytical study including patients less than 18 years of age with the diagnosis of skin or soft tissue infections in 2008 and 2009 meeting the criteria of Community-acquired infection. A prevalence of 41.9% among skin and soft tissue infections was found. Inducible resistance to clindamycin was detected in 1.3% of the strains and the infection shows a seasonal predilection for summer (P=0.003); 57.8% of the cases required hospitalization with a mean stay of 3.3±2.5 days. The susceptibility to clindamycin and co-trimoxazole is 88 and 97% respectively. The resistance to erythromycin has reached 92%. The main diagnoses at presentation was gluteal abscess plus cellulitis (34.2%).The prevalence of CA-MRSA is trending up and seems to become a large burden for the health system in our community. Clindamycin is still an excellent option in the community setting since inducible clindamycin resistance is extremely low in this community. Co-trimoxazole should be kept as a reserved drug to avoid the rapid resurgence resistance in the community.

  17. Fault current limiter-predominantly resistive behavior of a BSCCO shielded-core reactor

    SciTech Connect

    Ennis, M. G.; Tobin, T. J.; Cha, Y. S.; Hull, J. R.

    2000-06-30

    Tests were conducted to determine the electrical and magnetic characteristics of a superconductor shielded core reactor (SSCR). The results show that a closed-core SSCR is predominantly a resistive device and an open-core SSCR is a hybrid resistive/inductive device. The open-core SSCR appears to dissipate less than the closed-core SSCR. However, the impedance of the open-core SSCR is less than that of the closed-core SSCR. Magnetic and thermal diffusion are believed to be the mechanism that facilitates the penetration of the superconductor tube under fault conditions.

  18. Evaluating the SCC resistance of underwater welds in sodium tetrathionate

    SciTech Connect

    White, R.A.; Angeliu, T.M.

    1997-12-01

    The susceptibility of welds to stress corrosion cracking (SCC) is enhanced by the surface residual tensile stresses generated by the typical welding process. However, underwater plasma transferred arc (PTA) welding has been shown to produce compressive surface residual stresses, an encouraging result if repairs of cracked boiling water reactor (BWR) components are to be made without further endangering them to SCC. This program was designed to verify that underwater PTA welds are resistant to SCC and to determine if underwater PTA welding could mitigate SCC in potentially susceptible welds. This was achieved by exposing various welds on solution annealed (SA) and SA + thermally sensitized 304 stainless steel at 25 C in a solution of 1.5 gm/liter of sodium sulfide added to 0.05M sodium tetrathionate, titrated to a pH of 1.25 with H{sub 2}SO{sub 4}. The autogeneous welds were produced using gas tungsten arc (GTA) and plasma transferred arc (PTA) welding under atmospheric conditions, and PTA welding underwater. After 1 hour of sodium tetrathionate exposure, GTA and air PTA welds exhibited SCC while the underwater PTA weld heat affected zones were more resistant. Underwater PTA welds bisecting a GTA weld eliminated the cracking in the GTA weld heat affected zone under certain conditions. The lack of IG cracking in the region influenced by the underwater PTA weld is consistent with the measurement of compressive surface residual stresses inherent to the underwater welding process.

  19. Current resistance sources and breeding strategies to mitigate Ug99 threat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Continued spread of race Ug99 (TTKSK) of Puccinia graminis from Eastern Africa to Yemen and Iran, and its evolution to overcome resistance genes Sr24 and Sr36 has further increased the genetic vulnerability of wheat crop in Africa, Middle East and Asia where about 90% of the area is sown to moderate...

  20. A Relative Resistance Ratio for Evaluation of Mexican Rice Borer (Lepidoptera: Crambidae) Susceptibility Among Sugarcane Cultivars.

    PubMed

    Wilson, Blake E; VanWeelden, Matthew T; Beuzelin, Julien M; Reagan, Thomas E; Way, Michael O; White, William H; Wilson, Lloyd T; Showler, Allan T

    2015-06-01

    The Mexican rice borer, Eoreuma loftini (Dyar), is a major pest of sugarcane (hybrids of Saccharum spp.) in Louisiana and Texas. Resistance to E. loftini was evaluated in 51 commercial and experimental cultivars of sugarcane, energycane (hybrids of Saccharum spp.), and sorghum [Sorghum bicolor (L.) Moench and hybrids of Sorghum spp.] in four replicated small plot field experiments from 2009 to 2012. A relative resistance ratio was developed to compare levels of susceptibility among cultivars based on the percentage of bored internodes and survival to adulthood. This index was able to separate cultivars into five resistance categories and provides a new method for comparing levels of resistance among cultivars. E. loftini pest pressure in 2009 was among the highest recorded with injury ranging from 55 to 88% bored internodes. Commercial sugarcane cultivar HoCP 85-845 was identified as resistant in three of four experiments, whereas HoCP 04-838 was identified as susceptible in all experiments. Of the five sugarcane cultivars in commercial production in the Rio Grande Valley of Texas, only TCP 87-3388 was categorized as resistant. Of the cultivars with potential for bioenergy production, all of the energycane cultivars demonstrated higher levels of resistance than high-biomass and sweet sorghum cultivars. Continued evaluation of cultivar resistance to E. loftini is important to development of effective integrated pest management strategies for this pest.

  1. Evaluation of coffee genotypes for root-knot nematode resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Meloidogyne konaensis causes severe damage to the root systems of Coffea arabica cv. Typica ‘Guatemala’ grown in Kona, Hawaii. Farmers currently employ grafting of the nematode tolerant C. liberica var. dewevrei ‘Fukunaga’ to C. arabica cv. Typica scions. Greenhouse experiments confirmed C. liberi...

  2. The Role of Evaluation and Plans for Evaluating the Current Testing Program.

    ERIC Educational Resources Information Center

    Winters, Lynn

    The Palos Verdes Peninsula Unified School District Office of Program Evaluation and Research is responsible for providing information for program development and improvement; providing test information to special programs coordinators; and acting as a clearinghouse for all information concerning tests, evaluation methodology, and educational…

  3. Excised leaf method for high volume evaluation of sorghum germplasm for resistance against Colletotrichum sublineolum

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Foliar phase of anthracnose, caused by Colletotrichum sublineolum is the most important leaf disease of sorghum. Due to the hyper-variable nature of the fungus, continuous evaluation of sorghum germplasm to identify new sources of resistance is imperative. Field and greenhouse evaluations for anth...

  4. Evaluation on an original resistivity inversion method of water flooding a conglomerate reservoir based on petrophysical analysis

    NASA Astrophysics Data System (ADS)

    Liu, Renqiang; Duan, Yonggang; Tan, Fengqi; Wang, Guochang; Qin, Jianhua; Neupane, Bhupati

    2015-10-01

    An accurate inversion of original reservoir resistivity is an important problem for waterflood development in oilfields in the middle-late development period. This paper describes the theoretical model of original resistivity recovery for a conglomerate reservoir established by petrophysical models, based on the stratigraphic model of reservoir vertical invasion of the conglomerate reservoir of an oilfield. Likewise two influencing factors of the resistivity change with a water-flooded reservoir were analyzed. The first one is the clay volume decrease due to an injected water wash argillaceous particle and the reservoir resistivity changes are influenced by it, and the other is to inject water to displace crude oil in the pore space leading to the increase of the water-bearing volume. Moreover the conductive ions of the injected water and the original formation water exchange and balance because of their salinity difference, and the reservoir resistivity changes are also influenced by them. Through the analysis of the above influential factors based on the fine identification of conglomerate lithologies the inversion models of three variables, including changes in the amount of clay, the resistivity of the irreducible water and the increase of the water bearing volume, were established by core analysis data, production performance and well logging curves information, and accurately recovered the original reservoir resistivity of the conglomerate. The original oil saturation of the reservoir was calculated according to multiple linear regression models. Finally, the produced index is defined as the difference of the original oil saturation and current oil saturation to the original oil saturation ratio, and it eliminates the effects of conglomerate lithologies and heterogeneity for the quantitative evaluation of flooded layers by the use of the principle of relative value. Compared with traditional flooding sensitive parameters which are oil saturation and water

  5. Genotypic and phenotypic evaluation for benzimidazole resistance or susceptibility in Haemonchus contortus isolates.

    PubMed

    Arafa, Waleed M; Holman, Patricia J; Craig, Thomas M

    2017-02-01

    Haemonchus contortus isolates were evaluated for benzimidazole (BZ) resistance or susceptibility by allele-specific PCR based on β-tubulin isotype 1 gene polymorphisms at the F167Y, E198A, and F200Y sites. Two isolates, one presumed susceptible from wild pronghorn antelope (PH) and one known to be resistant from goats (VM), were also assayed phenotypically for BZ resistance or susceptibility in the larval development assay (Drenchrite®). The BZ EC50 was 0.198 μM (intermediate between susceptible and weak resistant) for PH with critical well 5 (intermediate between susceptible and weak resistant) and 1.456 μM (intermediate weak resistant and resistant) for VM with critical well 8.5 (resistant). Genotypically, DNA extracted from pooled VM L3 larvae in the Drenchrite® wells with the highest BZ concentration was homozygous susceptible (SS) at the F167Y and E198A sites and homozygous resistant (RR) at the F200Y site by PCR, and sequence analysis bore this out. PH L3 larvae DNA from a control well (no BZ) was SS at all three sites by PCR, confirmed by sequence analysis. All single adult worm samples (N = 21) from PH, VM, Egypt goat (EG), and a Texas llama were SS at F167Y and E198A by PCR; however, only 3 PH worms and 1 EG worm were SS at F200Y. Three additional PH worms were RS and upon cloning two clones were identified as resistant by sequencing and two as susceptible. Clones from single adult worms VM, llama, and EG samples that were RR by PCR at F200Y were sequence verified as resistant. In this study, F200Y was the most frequently found genotypic marker for BZ resistance or susceptibility in the different Haemonchus isolates.

  6. Intern doctors’ views on the current and future antibiotic resistance situation of Chattagram Maa O Shishu Hospital Medical College, Bangladesh

    PubMed Central

    Hoque, Rozina; Mostafa, Asma; Haque, Mainul

    2015-01-01

    Background Bacterial resistance due to antibiotic misuse is reported every day. Such threat calls for a consensus to develop new strategies to prevent the development of antibiotic resistance of bacteria. Medical doctors must play a pivotal role to control and prevent the misuse of antibiotics. There were complaints that prescribers are lacking behind in updates and advancement in the field. To address such knowledge gap, a study was conducted to know the views of interns on the current antibiotic resistance situation in a teaching hospital in Bangladesh. Methods This study was a cross-sectional, randomized, and questionnaire-based survey. Interns of the medicine, gynecology, and surgery departments of Chattagram Maa O Shishu Hospital Medical College were the study population. Results Out of 50 respondents, 98% would like more education on antibiotic selection. All respondents believed that prescribing inappropriate or unnecessary antibiotics was professionally unethical. Ninety percent of the participants were confident in making an accurate diagnosis of infection. Eighty-four percent of them were confident about dosage schedule. In all, 98% participants thought that antibiotic resistance is a national problem and 64% of the respondents thought that same problem also existed in their hospital. Study participants were of the view that 41%–60% of antibiotic usages are irrational in Bangladesh. Fifty-eight percent of the study population thought that antimicrobial resistance (AR) would be a greater problem in the future. Conclusion The interns believe that there is a knowledge gap on AR. More emphasis should be given to AR and its implications in the undergraduate curriculum. Latest national and international guidelines for antimicrobial therapy and resistance should be made available to the interns. PMID:26316762

  7. Standardized plant disease evaluations will enhance resistance gene discovery

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Gene discovery and marker development using DNA-based tools require plant populations with well documented phenotypes. If dissimilar phenotype evaluation methods or data scoring techniques are employed with different crops, or at different labs for the same crops, then data mining for genetic marker...

  8. Current status of the availability, development, and use of host plant resistance to nematodes.

    PubMed

    Roberts, P A

    1992-06-01

    Host plant resistance (HPR) to nematodes has been identified in many major crops and related wild germplasm. Most HPR is to the more specialized, sedentary endoparasitic genera and species, e.g., Globodera, Heterodera, Meloidogyne, Nacobbus, Rotylenchulus, and Tylenchulus. Some HPR has been developed or identified also to certain migratory endoparasites (Aphelenchoides, Ditylenchus, Pratylenchus, Radopholus) in a few hosts. Commercial use of HPR remains limited, despite its benefits to crop production when deployed appropriately. Restricted use and availability of HPR result from problems associated with transfer of resistance into acceptable cultivars. Difficulties occur in gene transfer to acceptable cultivars because of incompatibility barriers to hybridization or linkage to undesirable traits, for example in cucurbitaceous and solanaceous crops and sugarbeet. Specificity of HPR to only one species, or one or few pathotypes, as it relates to resistance durability and nematode virulence, and HPR response to abiotic factors such as high soil temperature, also limit availability and utility. A scheme for HPR development is presented to emphasize nematology research and information requirements for expanding HPR use in nematode control programs, for example in common bean, sugarbeet, and tomato. Nonbiological factors that influence HPR usage are discussed, including heavy reliance on nematicide programs, low priority of nematode HPR in many breeding programs, and insufficient breeder-nematologist collaboration.

  9. Contact Precautions for Multidrug-Resistant Organisms (MDROs): Current Recommendations and Actual Practice

    PubMed Central

    Clock, Sarah A.; Cohen, Bevin; Behta, Maryam; Ross, Barbara; Larson, Elaine L.

    2009-01-01

    Background Contact precautions are recommended for interactions with patients colonized/infected with multidrug-resistant organisms; however, rates of contact precautions practice are unknown. Methods Observers recorded the availability of supplies and staff/visitor adherence to contact precautions at rooms of patients indicated for contact precautions. Data were collected at three sites in a New York City hospital network. Results Contact precautions signs were present for 85.4% of indicated patients. The largest proportions were indicated for isolation for vancomycin-resistant enterococci and methicillin-resistant Staphylococcus aureus cultures. Isolation carts were available outside 93.7-96.7% of rooms displaying signs, and personal protective equipment was available at rates of 49.4-72.1% for gloves (all sizes: small, medium, and large) and 91.7-95.2% for gowns. Overall adherence rates upon room entry and exit, respectively, were 19.4% and 48.4% for hand hygiene, 67.5% and 63.5% for gloves, and 67.9% and 77.1% for gowns. Adherence was significantly better in intensive care units (p<0.05) and by patient-care staff (p<0.05), and patient-care staff compliance with one contact precautions behavior was predictive of adherence to additional behaviors (p<0.001). Conclusions Our findings support the recommendation that methods to monitor contact precautions and identify and correct non-adherent practices should be a standard component of infection prevention and control programs. PMID:19913329

  10. Laboratory evaluation of cyromazine against insecticide-susceptible and -resistant mosquito larvae.

    PubMed

    Darriet, Frederic; Zaim, Morteza; Corbel, Vincent

    2008-03-01

    In this study, the activity of cyromazine was evaluated following WHO standard procedures against susceptible and resistant mosquito strains of Anopheles gambiae, Culex quinquefasciatus, and Aedes aegypti. The dose for 50% and 90% inhibition of adult emergence (IE50 and IE90) ranged from 0.028 mg/liter to 0.17 mg/liter and from 0.075 mg/liter to 0.42 mg/liter, respectively. The effects of cyromazine were closer to that of chitin synthesis inhibitors rather than that of juvenile hormone analogues, with only 10-20% pupal mortality. The toxicity of cyromazine was not strongly affected by the presence of common resistance mechanism, i.e., Kdr mutation and Ace.1(R) (resistance ratio from 0.5 to 2.3). The absence of cross resistance with common insecticides (pyrethroids, carbamates, organophosphates) makes cyromazine a potential candidate for disease vector control, especially for the management of insecticide resistance.

  11. Audiological Evaluation of Patients Taking Kanamycin for Multidrug Resistant Tuberculosis

    PubMed Central

    Sharma, Vishal; Bhagat, Sanjeev; Verma, Bhimsain; Singh, Ravinder; Singh, Surinderpal

    2016-01-01

    Introduction: The incidence of multidrug resistant tuberculosis is increasing in developing countries. Aminoglycosides are an integral part of second-line drugs, however ototoxicity is a major limitation for their use. This study aims to determine the extent of hearing loss in patients taking one of the commonly prescribed drugs for Multidrug resistant tuberculosis (MDR-TB), Kanamycin, at a Government Medical College, Patiala, Punjab, India, which is a 1200 bed tertiary care hospital. Materials and Methods: A total of 100 patients (68 males and 32 females) with confirmed diagnosis of MDR-TB were included in this study conducted between January 2012 and February 2014. Subjects were between 15 to 60 years of age, with a mean age of 37.46 ± 10.1. Pure tone audiometry (PTA) was performed before the start of the therapy, as a baseline, and was repeated after 1 week and 6 weeks of Kanamycin use to assess hearing loss as an effect of therapy. Results: Of the 100 patients examined, ototoxicity was found in 18 subjects post therapy. Incidence of high frequency hearing loss was 2% at week 1, and 12% after 6 weeks of follow up. However, 4% of the cases developed flat loss at week 6. The hearing loss was bilateral in 13 patients and unilateral in 5 patients. Ototoxicity was more common in males (66.67%) compared to females (33.3%). Maximum cases were found in the age group of 36 to 45 years (36.8%), the majority being from a rural background (83.3%). The association with socioeconomic status (P=0.024) and co-morbid conditions like diabetes and hypertension (P=0.001) reached statistical significance. Conclusion: Lack of specific guidelines to monitor patients taking aminoglycosides makes ototoxicity a major adverse effect of their use in MDR-TB. More studies are mandated to study the risk factors associated with the development of ototoxicity and for the development of alternate drugs for the treatment of MDR-TB. PMID:27429949

  12. Role of Combination Antimicrobial Therapy for Vancomycin-Resistant Enterococcus faecium Infections: Review of the Current Evidence.

    PubMed

    Yim, Juwon; Smith, Jordan R; Rybak, Michael J

    2017-03-08

    Enterococcus species are the second most common cause of nosocomial infections in the United States and are particularly concerning in critically ill patients with preexisting comorbid conditions. Rising resistance to antimicrobials that were historically used as front-line agents for treatment of enterococcal infections, such as ampicillin, vancomycin, and aminoglycosides, further complicates the treatment of these infections. Of particular concern are Enterococcus faecium strains that are associated with the highest rate of vancomycin resistance. The introduction of antimicrobial agents with specific activity against vancomycin-resistant Enterococcus (VRE) faecium including daptomycin, linezolid, quinupristin-dalfopristin, and tigecycline did not completely resolve this clinical dilemma. In this review, the mechanisms of action and resistance to currently available anti-VRE antimicrobial agents including newer agents such as oritavancin and dalbavancin will be presented. In addition, novel combination therapies including β-lactams and fosfomycin, and the promising results from in vitro, animal studies, and clinical experience in the treatment of VRE faecium will be discussed. This article is protected by copyright. All rights reserved.

  13. Using direct current resistivity sounding and geostatistics to aid in hydrogeological studies in the Choshuichi alluvial fan, Taiwan.

    PubMed

    Yang, Chieh-Hou; Lee, Wei-Feng

    2002-01-01

    Ground water reservoirs in the Choshuichi alluvial fan, central western Taiwan, were investigated using direct-current (DC) resistivity soundings at 190 locations, combined with hydrogeological measurements from 37 wells. In addition, attempts were made to calculate aquifer transmissivity from both surface DC resistivity measurements and geostatistically derived predictions of aquifer properties. DC resistivity sounding data are highly correlated to the hydraulic parameters in the Choshuichi alluvial fan. By estimating the spatial distribution of hydraulic conductivity from the kriged well data and the cokriged thickness of the correlative aquifer from both resistivity sounding data and well information, the transmissivity of the aquifer at each location can be obtained from the product of kriged hydraulic conductivity and computed thickness of the geoelectric layer. Thus, the spatial variation of the transmissivities in the study area is obtained. Our work is more comparable to Ahmed et al. (1988) than to the work of Niwas and Singhal (1981). The first "constraint" from Niwas and Singhal's work is a result of their use of linear regression. The geostatistical approach taken here (and by Ahmed et al. [1988]) is a natural improvement on the linear regression approach.

  14. Current State of Resistance to Antibiotics of Last-Resort in South Africa: A Review from a Public Health Perspective

    PubMed Central

    Osei Sekyere, John

    2016-01-01

    A review of the literature was undertaken to delineate the current level and mechanisms of resistance to carbapenems, colistin, and tigecycline in South Africa. Thirty-two English publications and 32 National Institute of Communicable Diseases communiqués identified between early January 2000 and 20 May, 2016 showed substantial reports of NDM (n = 860), OXA-48 (n = 584), VIM (n = 131), and IMP (n = 45) carbapenemases within this period, mainly in Klebsiella pneumoniae (n = 1138), Acinetobacter baumannii (n = 332), Enterobacter cloacae (n = 201), and Serratia marcescens (n = 108). Colistin and tigecycline resistance was prevalent among K. pneumoniae, A. baumannii, S. marcescens, and E. cloacae. The first mcr-1 colistin resistance gene to be detected in South Africa was reported in Escherichia coli from livestock as well as from hospitalized and outpatients. There are increasing reports of NDM and OXA-48 carbapenemases among Enterobacteriaceae and A. baumannii in South Africa. Mcr-1 is now present in South African patients and livestock. Resistance to carbapenems, colistin, and tigecycline restricts infection management options for clinicians. PMID:27747206

  15. Current State of Resistance to Antibiotics of Last-Resort in South Africa: A Review from a Public Health Perspective.

    PubMed

    Osei Sekyere, John

    2016-01-01

    A review of the literature was undertaken to delineate the current level and mechanisms of resistance to carbapenems, colistin, and tigecycline in South Africa. Thirty-two English publications and 32 National Institute of Communicable Diseases communiqués identified between early January 2000 and 20 May, 2016 showed substantial reports of NDM (n = 860), OXA-48 (n = 584), VIM (n = 131), and IMP (n = 45) carbapenemases within this period, mainly in Klebsiella pneumoniae (n = 1138), Acinetobacter baumannii (n = 332), Enterobacter cloacae (n = 201), and Serratia marcescens (n = 108). Colistin and tigecycline resistance was prevalent among K. pneumoniae, A. baumannii, S. marcescens, and E. cloacae. The first mcr-1 colistin resistance gene to be detected in South Africa was reported in Escherichia coli from livestock as well as from hospitalized and outpatients. There are increasing reports of NDM and OXA-48 carbapenemases among Enterobacteriaceae and A. baumannii in South Africa. Mcr-1 is now present in South African patients and livestock. Resistance to carbapenems, colistin, and tigecycline restricts infection management options for clinicians.

  16. Self-gravitating rotating anisotropic pressure plasma in presence of Hall current and electrical resistivity using generalized polytrope laws

    SciTech Connect

    Prajapati, R. P.; Chhajlani, R. K.; Soni, G. D.

    2008-06-15

    The effects of uniform rotation, finite electrical resistivity, electron inertia, and Hall current on the self-gravitational instability of anisotropic pressure plasma with generalized polytrope laws have been studied. A general dispersion relation is obtained with the help of the relevant linearized perturbed magnetohydrodynamic (MHD) equations incorporating the relevant contributions of various effects of the problem using the method of normal mode analysis. The general dispersion relation is further reduced for the special cases of rotation; i.e., parallel and perpendicular to the direction of the magnetic field. The longitudinal and transverse modes of propagation are discussed separately for investigation of condition of instability. The effects of rotation, Hall current, finite electron inertia, and polytropic indices are discussed on the gravitational, ''firehose,'' and ''mirror'' instabilities. The numerical calculations have been performed to obtain the dependence of the growth rate of the gravitational unstable mode on the various physical parameters involved. The finite electrical resistivity, rotation, and Hall current have a stabilizing influence on the growth rate of the unstable mode of wave propagation. The finite electrical resistivity removes the effect of magnetic field and polytropic index from the condition of instability in the transverse mode of propagation for both the cases of rotation. It is also found that the Jeans criterion of gravitational instability depends upon rotation, electron inertia, and polytropic indices. In the case of transverse mode of propagation with the axis of rotation parallel to the magnetic field, it is observed that the region of instability and the value of the critical Jeans wavenumber are larger for the Chew-Goldberger-Low set of equations in comparison with the MHD set of equations. The stability of the system is discussed by applying Routh-Hurwitz criterion. The inclusion of rotation or Hall current or both

  17. Resistance to Acarapis woodi by honey bees (Hymenoptera: Apidae): divergent selection and evaluation of selection progress.

    PubMed

    Nasr, M E; Otis, G W; Scott-Dupree, C D

    2001-04-01

    Two generations of honey bees, Apis mellifera L., selected for resistance to tracheal mites, Acarapis woodi (Rennie), were produced from a foundation stock. The mite resistant lines had significantly low mite abundances and prevalences in each selected generation. The high mite-resistant lines of the first selected generation showed resistance equal to that of bees that had undergone natural selection from tracheal mite infestations for 3 yr in New York. Additionally, the high mite-resistant lines of the second selected generation and Buckfast bees had significantly lower mite abundances and prevalences than honey bees from control colonies which had never been exposed to tracheal mite infestation in Ontario. These results corroborate studies that have shown that honey bees possess genetic components for tracheal mite resistance that can be readily enhanced in a breeding program. The two methods used for evaluating relative resistance of honey bees to tracheal mites, a short-term bioassay and evaluation in field colonies, were positively correlated (rs = 0.64, P < 0.001).

  18. Method for exciting inductive-resistive loads with high and controllable direct current

    DOEpatents

    Hill, Jr., Homer M.

    1976-01-01

    Apparatus and method for transmitting dc power to a load circuit by applying a dc voltage from a standard waveform synthesizer to duration modulate a bipolar rectangular wave generator. As the amplitude of the dc voltage increases, the widths of the rectangular wave generator output pulses increase, and as the amplitude of the dc voltage decreases, the widths of the rectangular wave generator output pulses decrease. Thus, the waveform synthesizer selectively changes the durations of the rectangular wave generator bipolar output pulses so as to produce a rectangular wave ac carrier that is duration modulated in accordance with and in direct proportion to the voltage amplitude from the synthesizer. Thereupon, by transferring the carrier to the load circuit through an amplifier and a rectifier, the load current also corresponds directly to the voltage amplitude from the synthesizer. To this end, the rectified wave at less than 100% duty factor, amounts to a doubled frequency direct voltage pulse train for applying a direct current to the load, while the current ripple is minimized by a high L/R in the load circuit. In one embodiment, a power transmitting power amplifier means having a dc power supply is matched to the load circuit through a transformer for current magnification without sacrificing load current duration capability, while negative voltage and current feedback are provided in order to insure good output fidelity.

  19. Evaluation of antimicrobial resistance of Campylobacter spp. isolated from broiler carcasses.

    PubMed

    Ferro, I D; Benetti, T M; Oliveira, T C R M; Abrahão, W M; Farah, S M S S; Luciano, F B; Macedo, R E F

    2015-01-01

    1. The aim of the present study was to evaluate the antimicrobial resistance of Campylobacter strains (C. jejuni, C. coli and C. lari) isolated from broiler carcasses processed in the State of Paraná, Brazil. 2. Rates of microbial resistance and susceptibility were assessed by both Disk Diffusion (DD) and Etest (Minimum Inhibitory Concentration) techniques. Antibiotics were tested using DD (12 antibiotics) and/or MIC (7 antibiotics) methods. 3. A total of 95.8% of the strains were resistant to at least two agents. In terms of multidrug resistance, 75% of strains were resistant to three or more groups of antibiotics. The highest rates of resistance were detected for cefalotin, ciprofloxacin, tetracycline and nalidixic acid. A high rate of susceptibility of the strains to erythromycin (95.8%) was found confirming that this is considered the agent of choice for treating campylobacteriosis. Comparison of the microbial resistance and susceptibility, as determined simultaneously by the two methods, found the techniques to be statistically equivalent for 5 out of the 6 antibiotics tested. 4. The results of this study suggest the need for adopting measures to control the use of antibiotics in broiler production to prevent multidrug resistance of Campylobacter strains and reduce the risk of serious human diseases caused by the consumption of contaminated chicken meat.

  20. Determining the base resistance of InP HBTs: An evaluation of methods and structures

    NASA Astrophysics Data System (ADS)

    Nardmann, Tobias; Krause, Julia; Pawlak, Andreas; Schroter, Michael

    2016-09-01

    Many different methods can be found in the literature for determining both the internal and external base series resistance based on single transistor terminal characteristics. Those methods are not equally reliable or applicable for all technologies, device sizes and speeds. In this review, the most common methods are evaluated regarding their suitability for InP heterojunction bipolar transistors (HBTs) based on both measured and simulated data. Using data generated by a sophisticated physics-based compact model allows an evaluation of the extraction method precision by comparing the extracted parameter value to its known value. Based on these simulations, this study provides insight into the limitations of the applied methods, causes for errors and possible error mitigation. In addition to extraction methods based on just transistor terminal characteristics, test structures for separately determining the components of the base resistance from sheet and specific contact resistances are discussed and applied to serve as reference for the experimental evaluation.

  1. Skeletal Muscle Function Deficits in the Elderly: Current Perspectives on Resistance Training

    PubMed Central

    Papa, Evan V.; Dong, Xiaoyang; Hassan, Mahdi

    2017-01-01

    A variety of changes in skeletal muscle occur with aging. Sarcopenia is the age-associated loss of muscle mass and is one of the main contributors to musculoskeletal impairments in the elderly. Traditional definitions of sarcopenia focused on the size of human skeletal muscle. However, increasing evidence in older adults suggests that low muscle mass is associated with weakness, and weakness is strongly associated with function and disability. In recent years a global trend has shifted toward more encompassing definitions for the loss of muscle mass which include decreases in physical function. This review focuses on skeletal muscle function deficits in the elderly and how these age-associated deficits can be ameliorated by resistance training. We set forth evidence that skeletal muscle deficits arise from changes within the muscle, including reduced fiber size, decreased satellite cell and fiber numbers, and decreased expression of myosin heavy chain (MHC) isoform IIa. Finally, we provide recommendations for clinical geriatric practice regarding how resistance training can attenuate the increase in age-associated skeletal muscle function deficits. Practitioners should consider encouraging patients who are reluctant to exercise to move along a continuum of activity between “no acticity” on one end and “recommended daily amounts” on the other. PMID:28191501

  2. Current concepts about chromium supplementation in type 2 diabetes and insulin resistance.

    PubMed

    Wang, Zhong Q; Cefalu, William T

    2010-04-01

    Chromium has been established to be an essential trace element in mammals in regard to maintenance of normal carbohydrate metabolism. Studies that provided chromium to human subjects in documented deficiency states noted improved glucose levels. However, controversy exists as to whether dietary supplementation with chromium should be routinely recommended in subjects without documented deficiencies. Over the recent past, several well-designed clinical trials have provided evidence in favor of and against a beneficial effect of chromium. It appears that across all subject phenotypes (eg, lean and obese, insulin sensitive and insulin resistant), a consistent significant and beneficial effect of chromium may not be observed. Specifically, recent data fail to demonstrate significant improvement in carbohydrate metabolism in individuals with metabolic syndrome, impaired glucose tolerance, or consistently in individuals with type 2 diabetes. However, patient selection may be an important factor in determining clinical response, as it was concluded that a clinical response to chromium (ie, decreased glucose and improved insulin sensitivity) may be more likely in insulin-resistant individuals with type 2 diabetes who have more elevated fasting glucose and hemoglobin A(1c) levels.

  3. Evaluation Of Saltstone Mixer Paddle Configuration For Improved Wear Resistance

    SciTech Connect

    Reigel, M. M.; Fowley, M. D.; Pickenheim, B. R.

    2012-09-27

    A soft metal with low wear resistance (6000 series aluminum), was used to minimize run time while maximizing wear rate. Two paddle configurations were tested, with the first four paddles after the augers replaced by the wear paddles. The first configuration was all flat paddles, with the first paddle not aligned with the augers and is consistent with present SPF mixer. The second configuration had helical paddles for the first three stages after the augers and a flat paddle at the fourth stage. The first helical paddle was aligned with the auger flight for the second configuration. The all flat paddle configuration wear rate was approximately double the wear rate of the helical paddles for the first two sets of paddles after the augers. For both configurations, there was little or no wear on the third and fourth paddle sets based on mass change, indicating that the fully wetted premix materials are much less abrasive than the un-wetted or partially wetted premix. Additionally, inspection of the wear surface of the paddles at higher magnification showed the flat paddles were worn much more than the helical and is consistent with the wear rates. Aligning the auger discharge flight with the first set of helical paddles was effective in reducing the wear rate as compared to the flat paddle configuration. Changing the paddle configuration from flat to helical resulted in a slight increase in rheological properties. Although, both tests produced grout-like material that is within the processing rage of the SPF, it should be noted that cement is not included in the premix and water was used rather than salt solution, which does affect the rheology of the fresh grout. The higher rheological properties from the helical wear test are most likely due to the reduced number of shearing paddles in the mixer. In addition, there is variation in the rheological data for each wear test. This is most likely due to the way that the dry feeds enter the mixer from the dry feeder. The

  4. Performance evaluation of high-temperature superconducting current leads for micro-SMES systems

    NASA Astrophysics Data System (ADS)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Buckles, W. E.; Weber, B. R.; Yang, S. T.

    As part of the U.S. Department of Energy's Superconductivity Technology Program, Argonne National Laboratory and Superconductivity, Inc., are developing high-temperature superconductor (HTS) current leads for application to micro-SMES systems. Two 1500-A HTS leads have been designed and constructed. A component performance evaluation program was conducted to confirm performance predictions and/or to qualify the design features for construction. The evaluations included HTS characteristics, demountable electrical connections, and heat intercept effectiveness. The performance of current lead assemblies is being evaluated in a zero-magnetic-field test program that included assembly procedures, tooling, and quality assurance; thermal and electrical performance; and flow and mechanical characteristics. The leads were installed in a liquid helium test cryostat and connected at their cold ends by a current jumper. The leads were heat intercepted with a cryocooler.

  5. Evaluation of the corrosion resistance of Fe-Al-Cr alloys in simulated low NOx environments

    SciTech Connect

    Deacon, R.M.; DuPont, J.N.; Kiely, C.J.; Marder, A.R.; Tortorelli, P.F.

    2009-08-15

    Due to their excellent corrosion resistance, iron aluminum alloys are currently being considered for use as weld claddings in fossil fuel fired power plants. The susceptibility to hydrogen cracking of these alloys at higher aluminum concentrations has led researchers to examine the effect of chromium additions on the corrosion resistance of lower aluminum alloys. In this work, three iron aluminum alloys were exposed to simulated coal combustion environments at 500 and 700{sup o}C for short (100 h) and long (5000 h) isothermal durations. Scanning electron microscopy was used to analyze the corrosion products. All alloys exhibited excellent corrosion resistance during short term exposures. For longer test times, increasing the aluminum concentration improved alloy corrosion resistance. The addition of chromium to the binary iron aluminum alloy prevented the formation iron sulfide and resulted in slower corrosion kinetics. A general classification of the scales developed on these alloys is presented.

  6. The distribution of low-threshold TTX-resistant Na⁺ currents in rat trigeminal ganglion cells.

    PubMed

    Scroggs, R S

    2012-10-11

    The distribution of low-threshold tetrodotoxin-resistant (TTX-r) Na(+) current and its co-expression with high-threshold TTX-r Na(+) current were studied in randomly selected acutely dissociated rat trigeminal ganglion (non-identified TG cells) and TG cells serving the temporomandibular joint (TMJ-TG cells). Conditions previously shown to enhance Na(V)1.9 channel-mediated currents (holding potential (HP) -80 mV, 130-mM fluoride internally) were employed to amplify the low-threshold Na(+) current. Under these conditions, detectable low-threshold Na(+) current was exhibited by 16 out of 21 non-identified TG cells (average, 1810 ± 358 pA), and by nine of 14 TMJ-TG cells (average, 959 ± 525 pA). The low-threshold Na(+) current began to activate around -55 mV and was inactivated by holding TG cells at -60 mV and delivering 40-ms test potentials (TPs) to 0 mV. The inactivation was long lasting, recovering only 8 ± 3% over a 5-min period after the HP was returned to -80 mV. Following low-threshold Na(+) current inactivation, high-threshold TTX-r Na(+) current, evoked from HP -60 mV, was observed. High-threshold Na(+) current amplitude averaged 16,592 ± 3913 pA for TPs to 0 mV, was first detectable at an average TP of -34 ± 1.3 mV, and was ½ activated at -7.1 ± 2.3 mV. In TG cells expressing prominent low-threshold Na(+) currents, changing the external solution to one containing 0 mM Na(+) reduced the amount of current required to hold the cells at -80 mV through -50 mV, the peak effect being observed at HP -60 mV. TG cells recorded from with a more physiological pipette solution containing chloride instead of fluoride exhibited small low-threshold Na(+) currents, which were greatly increased upon superfusion of the TG cells with the adenylyl cyclase (AC) activator forskolin. These data suggest two hypotheses: (1) low- and high-threshold Na(V)1.9 and Na(V)1.8 channels, respectively, are frequently co-expressed in TG neurons serving the TMJ and other structures, and

  7. Evaluation and Improvement of Eddy Current Position Sensors in Magnetically Suspended Flywheel Systems

    NASA Technical Reports Server (NTRS)

    Dever, Timothy P.; Palazzolo, Alan B.; Thomas, Erwin M., III; Jansen, Ralph H.; McLallin, Kerry (Technical Monitor); Soeder, James (Technical Monitor)

    2001-01-01

    Eddy current position sensor performance is evaluated for use in a high-speed flywheel development system. The flywheel utilizes a five axis active magnetic bearing system. The eddy current sensors are used for position feedback for the bearing controller. Measured characteristics include sensitivity to multiple target materials and susceptibility to noise from the magnetic bearings and from sensor-to-sensor crosstalk. Improvements in axial sensor configuration and techniques for noise reduction are described.

  8. Renal Denervation for Treating Resistant Hypertension: Current Evidence and Future Insights from a Global Perspective

    PubMed Central

    Castro Torres, Y.; Katholi, Richard E.

    2013-01-01

    Adequate blood pressure control represents an important goal for all physicians due to the complications of hypertension which reduce patients' quality of life. A new interventional strategy to reduce blood pressure has been developed for patients with resistant hypertension. Catheter-based renal denervation has demonstrated excellent results in recent investigations associated with few side effects. With the growing diffusion of this technique worldwide, some medical societies have published consensus statements to guide physicians how to best apply this procedure. Questions remain to be answered such as the long-term durability of renal denervation, the efficacy in patients with other sympathetically mediated diseases, and whether renal denervation would benefit patients with stage 1 hypertension. PMID:24369496

  9. The current and future roles of neonatal infection surveillance programmes in combating antimicrobial resistance.

    PubMed

    Cailes, Benjamin; Vergnano, Stefania; Kortsalioudaki, Christina; Heath, Paul; Sharland, Mike

    2015-11-01

    Neonatal sepsis is an important cause of morbidity and mortality, particularly in premature or low birth weight babies. Hospital-acquired blood stream infections represent a significant and largely preventable cause of disease in this population. Neonatal units have been identified as a common site for the development and transmission of antimicrobial-resistant pathogens, a significant issue in modern medicine. Neonatal surveillance programmes collect prospective data on infection rates and may be used to optimise therapy, benchmark practice and develop quality improvement programmes. Despite this, the number of networks is relatively few and these are largely concentrated in resource-rich nations. Furthermore, surveillance definitions may vary between programmes impairing our ability to draw comparisons between them. Better harmonisation is required between networks to ensure that they achieve their potential as a valuable tool for benchmarking of hospital-acquired infection rates between units.

  10. Performance evaluation of high-temperature superconducting current leads for micro-SMES systems

    NASA Astrophysics Data System (ADS)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Buckles, W. E.; Weber, B. R.; Yang, S. T.

    As part of the US Department of Energy's Superconductivity Technology Program, Argonne National Laboratory and Superconductivity, Inc., are developing high-temperature superconductor (HTS) current leads for application to micro-superconducting magnetic energy storage systems. Two 1500-A HTS leads have been designed and constructed. The performance of the current lead assemblies is being evaluated in a zero-magnetic-field test program that includes assembly procedures, tooling, and quality assurance; thermal and electrical performance; and flow and mechanical characteristics. Results of evaluations performed to data are presented.

  11. Evaluation of antiseptics by the modified phenol coefficient method: sensitivity of methicillin-resistant Staphylococcus aureus.

    PubMed

    Sasatsu, M; Shimizu, K; Noguchi, N; Kono, M

    1994-01-01

    The relationship between an effective concentration and the duration of exposure to antiseptics was evaluated in strains of Staphylococcus aureus with a known genetic background, which include methicillin-resistant strains, using a modified version of the phenol coefficient method as part of an effort to investigate the antiseptic resistance of S. aureus. Chlorhexidine digluconate killed an antiseptic-sensitive strain within 1.5 min at 22 degrees C at a standard concentration (0.1%), whereas resistant strains still survived after 1.5 min. Povidone-iodine killed the sensitive strain within 1.5 min at a concentration of 0.1%, whereas it took this agent 3.0 and 4.5 min to kill low- and high-level resistant strains, respectively, at a concentration of 0.8%. These results indicate that the modified phenol coefficient method used is suitable for the evaluation of the sensitivity of microorganisms to antiseptics. An antiseptic-resistant chain that was associated with the ebr gene exhibited cross-resistance to povidone-iodine.

  12. Evaluation of body weight, insulin resistance, leptin and adiponectin levels in premenopausal women with hyperprolactinemia.

    PubMed

    Atmaca, Aysegul; Bilgici, Birsen; Ecemis, Gulcin Cengiz; Tuncel, Ozgur Korhan

    2013-12-01

    The effects of hyperprolactinemia on metabolic parameters are not clear and a few data evaluating adiponectin levels in prolactinoma and idiopathic hyperprolactinemia exist. The aim of this study was to evaluate the effects of hyperprolactinemia on body weight, insulin resistance, beta cell function, and leptin and adiponectin levels in premenopausal women with hyperprolactinemia. Forty premenopausal women with prolactinoma or idiopathic hyperprolactinemia were compared to 41 age-matched healthy premenopausal women with regard to body weight, body mass index, waist and hip circumferences, waist to hip ratio, fasting plasma glucose, insulin levels, insulin resistance measured by homeostasis model assessment (HOMA)-insulin resistance index, beta cell function measured by HOMA-β index, leptin and adiponectin levels. Plasma insulin levels and HOMA indexes (both insulin resistance and beta indexes) were significantly higher in hyperprolactinemic women. The other parameters were similar between both groups. There was a positive correlation between prolactin levels and fasting plasma glucose in hyperprolactinemic women. The results of this study showed that high prolactin levels may be associated with hyperinsulinemia and insulin resistance in premenopausal women. This effect seems to be independent of body weight, leptin and adiponectin levels. High prolactin levels may directly stimulate insulin secretion from pancreas and directly cause hepatic and whole-body insulin resistance.

  13. [Evaluation of disease management programs--current deficits, demands and methods].

    PubMed

    Gerlach, Ferdinand M; Beyer, Martin; Szecsenyi, Joachim; Raspe, Heiner

    2003-10-01

    The evaluation of disease management programmes is necessary and has been made obligatory in Germany by the Fifth Book of Social Code. So far there has been extensive ambiguity as regards the precise definition of suitable strategies for the evaluation. Considering the scientific evaluation of the diabetes contract in North-Rhine current deficits of the evaluation of already existing programmes for chronically ill patients are exemplarily described. On the basis of international experience reasonable demands are discussed that ought to be accomplished when evaluating the effectiveness and benefit of the programmes. Taking the British Medical Research Council as an example, a four-step model will be suggested as a loophole in the methodological dilemma of varying suitable study designs, which allows for the adequate evaluation of even complex interventions.

  14. Evaluation of EUV resist performance below 20nm CD using helium ion lithography

    NASA Astrophysics Data System (ADS)

    Maas, Diederik; van Veldhoven, Emile; van Langen-Suurling, Anja; Alkemade, Paul F. A.; Wuister, Sander; Hoefnagels, Rik; Verspaget, Coen; Meessen, Jeroen; Fliervoet, Timon

    2014-04-01

    For the introduction of EUV lithography, development of high performance EUV resists is of key importance. This development involves studies into resist sensitivity, resolving power and pattern uniformity. We have used a sub-nanometer-sized 30 keV helium ion beam to expose chemically amplified (CAR) EUV resists. There are similarities in the response of resists to He+ ions and EUV photons: both excite Secondary Electrons with similar energy distributions.The weak backscattering of the He+ ions results in ultra-low proximity effects. This fact enables the exposure of dense and detailed patterns by focused He+ ion beams without the need for proximity correction. This paper presents contact holes and lines at 40-nm pitch in an EUV CAR resist. We have used resist sensitivity, contrast, resolution (CD) and pattern fidelity (LCDU, LWR and dose-to-print) as metrics for a comparison of SHIBL with EUVL. We show that Scanning Helium Ion Beam Lithography (SHIBL) can be a useful and economically attractive technology to (pre-)screen novel EUV resists prior to their final performance evaluation in an EUV scanner.

  15. Evaluation of plant resistance inducers on different winter soft wheat cultivars against Septoria leaf blotch.

    PubMed

    Ors, M; Siah, A; Randoux, B; Selim, S; Boizet, F; Couleaud, G; Maumene, C; Halama, P; Reignault, Ph

    2012-01-01

    Septoria tritici blotch (STB) caused by Mycosphaerella graminicola (anamorph: Zymoseptoria tritici) is one of the most devastating foliar diseases on bread wheat (Triticum aestivum L.). Because of the emergence of fungal strains highly resistant to mainly used fungicides and the deleterious impacts of these fungicides on the environment, development of alternative control strategies to protect wheat crops against STB is needed. The induction of plant resistance by elicitors is likely to be a helpful alternative. Our study aims at characterizing the efficiency of potential resistance inducers towards STB in three bread wheat cultivars differing in their resistance levels to the pathogen: Alixan (susceptible), Premio (moderately resistant) and Altigo (resistant). These cultivars were inoculated under controlled and semi-controlled conditions with the pathogenic M. graminicolo strain T01193 in order to assess the protective effect of three potential resistance inducers against the disease. Moreover, the direct antifungal effect bf these products was evaluated in vitro at different concentrations in order to verify their potential biocide activity. Furthermore, cytological analyses were performed in order to determine the effects of these products on the fungal infection process and to compare these effects among the three wheat cultivars. Finally, reactive oxygen species metabolism was investigated in the three cultivars during their interaction with T01193 by measuring peroxidase activity.

  16. Evaluation of Resistance to Ralstonia solanacearum in Tomato Genetic Resources at Seedling Stage.

    PubMed

    Kim, Sang Gyu; Hur, On-Sook; Ro, Na-Young; Ko, Ho-Cheol; Rhee, Ju-Hee; Sung, Jung Sook; Ryu, Kyoung-Yul; Lee, Sok-Young; Baek, Hyung Jin

    2016-02-01

    Bacterial wilt of tomatoes caused by Ralstonia solanacearum is a devastating disease that limits the production of tomato in Korea. The best way to control this disease is using genetically resistant tomato plant. The resistance degree to R. solanacearum was evaluated for 285 tomato accessions conserved in the National Agrobiodiversity Center of Rural Development Administration. These accessions of tomato were originated from 23 countries. Disease severity of tomato accessions was investigated from 7 days to 14 days at an interval of 7 days after inoculation of R. solanacearum under greenhouse conditions. A total of 279 accessions of tomato germplasm were susceptible to R. solanacearum, resulting in wilt and death in 70 to 90% of these plants. Two tomato accessions were moderately resistant to R. solanacearum. Only four accessions showed high resistance against R. solanacearum. No distinct symptom of bacterial wilt appeared on the resistant tomato germplasms for up to 14 days after inoculation of R. solanacearum. Microscopy of resistant tomato stems infected with R. solanacearum revealed limited bacterial spread with thickening of pit membrane and gum production. Therefore, these four resistant tomato germplasms could be used in tomato breeding program against bacterial wilt.

  17. An Evaluation of Four Current Models to Predict the Creep-Fatigue Interaction in Rene 95

    DTIC Science & Technology

    1979-06-01

    r’eracti were evaluated for their ability to predict fatigue behrivior at 1200?F (650 9C) of thermomechanical !y processed Rene 93--an advanced nickel-base...strain. This axial strain was controlled during the test by a servo-hydraulic testing machine. The specimen was " heated by an induction coil. A...AFML-TR-79- 4075 L V U rm• AN EVALUATION OF FOUR CURRENT MODELS TO PREDICT THE CREEP- FATIGUE INTERACTION IN RENf 95 Henry L. Bernstein Systems

  18. Evaluation of Plume Divergence and Facility Effects on Far-Field Faraday Probe Current Density Profiles

    DTIC Science & Technology

    2009-09-01

    elevated background pressure, compared nude Faraday probe designs, and evaluated design modifications to minimize uncertainty due to charge exchange...evaluated Faraday probe design and facility background pressure on collected ion current. A comparison of two nude Faraday probe designs concluded...140.5 Plasma potential in the region surrounding a nude Faraday probe has been measured to study the possibility of probe bias voltage acting as a

  19. Evaluation of the effects of crumb rubber and SBR on rutting resistance of asphalt concrete

    SciTech Connect

    Shih, Chuang-Tsair; Tia, Mang; Ruth, B.E.

    1996-12-31

    This paper presents the results of a study to evaluate the effects of addition of crumb rubber (CR) and styrene-butadiene rubber (SBR) on the rutting resistance of asphalt concrete. These two additives were blended with an AC-20 and an AC-30 grade asphalt cements at different levels of concentrations. These modified and unmodified asphalt blends were tested at intermediate and high temperatures to evaluate their rutting resistance characteristics. They were also used to make Florida type S-I structural surface mixtures. These mixtures were made into Marshall-size specimens by using Gyratory Testing Machine (GTM) equipped with air-roller to compact and density to three compaction levels which simulate three different conditions in the pavement. The FDOT`s (Florida Department of Transportation) Loaded Wheel Tester was also used to evaluate the rutting resistance of these asphalt mixtures. The test results indicate that the modified asphalt mixtures show relatively better rutting resistance and shear resistance as compared with the unmodified asphalt mixtures.

  20. Evaluation of metal-nanowire electrical contacts by measuring contact end resistance

    NASA Astrophysics Data System (ADS)

    Park, Hongsik; Beresford, Roderic; Ha, Ryong; Choi, Heon-Jin; Shin, Hyunjung; Xu, Jimmy

    2012-06-01

    It is known, but often unappreciated, that the performance of nanowire (NW)-based electrical devices can be significantly affected by electrical contacts between electrodes and NWs, sometimes to the extent that it is really the contacts that determine the performance. To correctly understand and design NW device operation, it is thus important to carefully measure the contact resistance and evaluate the contact parameters, specific contact resistance and transfer length. A four-terminal pattern or a transmission line model (TLM) pattern has been widely used to measure contact resistance of NW devices and the TLM has been typically used to extract contact parameters of NW devices. However, the conventional method assumes that the electrical properties of semiconducting NW regions covered by a metal are not changed after electrode formation. In this study, we report that the conventional methods for contact evaluation can give rise to considerable errors because of an altered property of the NW under the electrodes. We demonstrate that more correct contact resistance can be measured from the TLM pattern rather than the four-terminal pattern and correct contact parameters including the effects of changed NW properties under electrodes can be evaluated by using the contact end resistance measurement method.

  1. Evaluation of wet tantalum capacitors after exposure to extended periods of ripple current, volume 2

    NASA Technical Reports Server (NTRS)

    Ward, C. M.

    1975-01-01

    The application of tantalum capacitors in the Viking Lander includes dc voltage and ripple current electrical stress, high temperature during nonoperating times (sterilization), and high vibration and shock loads. The capacitors must survive these severe environments without any degradation if reliable performance is to be achieved. A test program was established to evaluate both wet-slug tantalum and wet-foil capacitors under conditions accurately duplicating actual Viking applications. Test results of the electrical performance characteristics during extended periods of ripple current, the characteristics of the internal silver migration as a function of extended periods of ripple current, and the existence of any memory characteristics are presented.

  2. Evaluation of wet tantalum capacitors after exposure to extended periods of ripple current, volume 1

    NASA Technical Reports Server (NTRS)

    Watson, G. W.; Lasharr, J. C.; Shumaker, M. J.

    1974-01-01

    The application of tantalum capacitors in the Viking Lander includes both dc voltage and ripple current electrical stress, high temperature during nonoperating times (sterilization), and high vibration and shock loads. The capacitors must survive these severe environments without any degradation if reliable performance is to be achieved. A test program was established to evaluate both wet-slug tantalum and wet-foil capacitors under conditions accurately duplicating actual Viking applications. Test results of the electrical performance characteristics during extended periods of ripple current, the characteristics of the internal silver migration as a function for extended periods of ripple current, and the existence of any memory characteristics are presented.

  3. Performance Evaluation of a 22.5/30 KW 270 Volts Direct Current Generator System

    DTIC Science & Technology

    1993-12-01

    AD-A275 106 WL-TR-93-2025 PERFORMANCE EVALUATION OF A 22.5/30 KW 270 VOLTS DIRECT CURRENT GENERATOR SYSTEM John G. Nairus, David A. Criminski Power...the addressee is no longer employed by your organization please notify WL/POOC , WPAFB, OH 45433- 7251 to help us maintain a current mailing list...30 kW 270 Volts Direct Program Element No. Current Generator System 62203F 6. AUTHOR(S) Work Unit No. 31452939 John G. Nairus, David A. Criminski 7

  4. Current Situation of Antimicrobial Resistance and Genetic Differences in Stenotrophomonas maltophilia Complex Isolates by Multilocus Variable Number of Tandem Repeat Analysis

    PubMed Central

    Song, Jae-Hoon

    2016-01-01

    Background Stenotrophomonas maltophilia is one of several opportunistic pathogens of growing significance. Several studies on the molecular epidemiology of S. maltophilia have shown clinical isolates to be genetically diverse. Materials and Methods A total of 121 clinical isolates tentatively identified as S. malophilia from seven tertiary-care hospitals in Korea from 2007 to 2011 were included. Species and groups were identified using partial gyrB gene sequences and antimicrobial susceptibility testing was performed using a broth microdilution method. Multi locus variable number of tandem repeat analysis (MLVA) surveys are used for subtyping. Results Based on partial gyrB gene sequences, 118 isolates were identified as belonging to the S. maltophilia complex. For all S. maltophilia isolates, the resistance rates to trimethoprime-sulfamethoxazole (TMP/SMX) and levofloxacin were the highest (both, 30.5%). Resistance rate to ceftazidime was 28.0%. 11.0% and 11.9% of 118 S. maltophilia isolates displayed resistance to piperacillin/tazobactam and tigecycline, respectively. Clade 1 and Clade 2 were definitely distinguished from the data of MLVA with amplification of loci. All 118 isolates were classified into several clusters as its identification. Conclusion Because of high resistance rates to TMP/SMX and levofloxacin, the clinical laboratory department should consider providing the data about other antimicrobial agents and treatment of S. maltophilia infections with a combination of antimicrobials can be considered in the current practice. The MLVA evaluated in this study provides a fast, portable, relatively low cost genotyping method that can be employed in genotypic linkage or transmission networks comparing to analysis of the gyrB gene. PMID:28032486

  5. Performance evaluation of wideband bio-impedance spectroscopy using constant voltage source and constant current source

    NASA Astrophysics Data System (ADS)

    Mohamadou, Youssoufa; In Oh, Tong; Wi, Hun; Sohal, Harsh; Farooq, Adnan; Woo, Eung Je; McEwan, Alistair Lee

    2012-10-01

    Current sources are widely used in bio-impedance spectroscopy (BIS) measurement systems to maximize current injection for increased signal to noise while keeping within medical safety specifications. High-performance current sources based on the Howland current pump with optimized impedance converters are able to minimize stray capacitance of the cables and setup. This approach is limited at high frequencies primarily due to the deteriorated output impedance of the constant current source when situated in a real measurement system. For this reason, voltage sources have been suggested, but they require a current sensing resistor, and the SNR reduces at low impedance loads due to the lower current required to maintain constant voltage. In this paper, we compare the performance of a current source-based BIS and a voltage source-based BIS, which use common components. The current source BIS is based on a Howland current pump and generalized impedance converters to maintain a high output impedance of more than 1 MΩ at 2 MHz. The voltage source BIS is based on voltage division between an internal current sensing resistor (Rs) and an external sample. To maintain high SNR, Rs is varied so that the source voltage is divided more or less equally. In order to calibrate the systems, we measured the transfer function of the BIS systems with several known resistor and capacitor loads. From this we may estimate the resistance and capacitance of biological tissues using the least-squares method to minimize error between the measured transimpedance excluding the system transfer function and that from an impedance model. When tested on realistic loads including discrete resistors and capacitors, and saline and agar phantoms, the voltage source-based BIS system had a wider bandwidth of 10 Hz to 2.2 MHz with less than 1% deviation from the expected spectra compared to more than 10% with the current source. The voltage source also showed an SNR of at least 60 dB up to 2.2 MHz in

  6. Voltage amplification of thermopower waves via current crowding at high resistances in self-propagating combustion waves.

    PubMed

    Yeo, Taehan; Hwang, Hayoung; Cho, Yonghwan; Shin, Dongjoon; Choi, Wonjoon

    2015-07-31

    Combustion wave propagation in micro/nanostructured materials generates a chemical-thermal-electrical energy conversion, which enables the creation of an unusual source of electrical energy, called a thermopower wave. In this paper, we report that high electrical resistance regimes would significantly amplify the output voltage of thermopower waves, because the current crowding creates a narrow path for charge carrier transport. We show that the structurally defective regions in the hybrid composites of chemical fuels and carbon nanotube (CNT) arrays determine both the resistance levels of the hybrid composites and the corresponding output voltage of thermopower waves. A sudden acceleration of the crowded charges would be induced by the moving reaction front of the combustion wave when the supplied driving force overcomes the potential barrier to cause charge carrier transport over the defective region. This property is investigated experimentally for the locally manipulated defective areas using diverse methods. In this study, thermopower waves in CNT-based hybrid composites are able to control the peak voltages in the range of 10-1000 mV by manipulating the resistance from 10 Ω to 100 kΩ. This controllable voltage generation from thermopower waves may enable applications using the combustion waves in micro/nanostructured materials and better understanding of the underlying physics.

  7. Voltage amplification of thermopower waves via current crowding at high resistances in self-propagating combustion waves

    NASA Astrophysics Data System (ADS)

    Yeo, Taehan; Hwang, Hayoung; Cho, Yonghwan; Shin, Dongjoon; Choi, Wonjoon

    2015-07-01

    Combustion wave propagation in micro/nanostructured materials generates a chemical-thermal-electrical energy conversion, which enables the creation of an unusual source of electrical energy, called a thermopower wave. In this paper, we report that high electrical resistance regimes would significantly amplify the output voltage of thermopower waves, because the current crowding creates a narrow path for charge carrier transport. We show that the structurally defective regions in the hybrid composites of chemical fuels and carbon nanotube (CNT) arrays determine both the resistance levels of the hybrid composites and the corresponding output voltage of thermopower waves. A sudden acceleration of the crowded charges would be induced by the moving reaction front of the combustion wave when the supplied driving force overcomes the potential barrier to cause charge carrier transport over the defective region. This property is investigated experimentally for the locally manipulated defective areas using diverse methods. In this study, thermopower waves in CNT-based hybrid composites are able to control the peak voltages in the range of 10-1000 mV by manipulating the resistance from 10 Ω to 100 kΩ. This controllable voltage generation from thermopower waves may enable applications using the combustion waves in micro/nanostructured materials and better understanding of the underlying physics.

  8. Enhancement of resistive switching under confined current path distribution enabled by insertion of atomically thin defective monolayer graphene

    PubMed Central

    Lee, Keundong; Hwang, Inrok; Lee, Sangik; Oh, Sungtaek; Lee, Dukhyun; Kim, Cheol Kyeom; Nam, Yoonseung; Hong, Sahwan; Yoon, Chansoo; Morgan, Robert B.; Kim, Hakseong; Seo, Sunae; Seo, David H.; Lee, Sangwook; Park, Bae Ho

    2015-01-01

    Resistive random access memory (ReRAM) devices have been extensively investigated resulting in significant enhancement of switching properties. However fluctuations in switching parameters are still critical weak points which cause serious failures during ‘reading’ and ‘writing’ operations of ReRAM devices. It is believed that such fluctuations may be originated by random creation and rupture of conducting filaments inside ReRAM oxides. Here, we introduce defective monolayer graphene between an oxide film and an electrode to induce confined current path distribution inside the oxide film, and thus control the creation and rupture of conducting filaments. The ReRAM device with an atomically thin interlayer of defective monolayer graphene reveals much reduced fluctuations in switching parameters compared to a conventional one. Our results demonstrate that defective monolayer graphene paves the way to reliable ReRAM devices operating under confined current path distribution. PMID:26161992

  9. Enhancement of resistive switching under confined current path distribution enabled by insertion of atomically thin defective monolayer graphene.

    PubMed

    Lee, Keundong; Hwang, Inrok; Lee, Sangik; Oh, Sungtaek; Lee, Dukhyun; Kim, Cheol Kyeom; Nam, Yoonseung; Hong, Sahwan; Yoon, Chansoo; Morgan, Robert B; Kim, Hakseong; Seo, Sunae; Seo, David H; Lee, Sangwook; Park, Bae Ho

    2015-07-10

    Resistive random access memory (ReRAM) devices have been extensively investigated resulting in significant enhancement of switching properties. However fluctuations in switching parameters are still critical weak points which cause serious failures during 'reading' and 'writing' operations of ReRAM devices. It is believed that such fluctuations may be originated by random creation and rupture of conducting filaments inside ReRAM oxides. Here, we introduce defective monolayer graphene between an oxide film and an electrode to induce confined current path distribution inside the oxide film, and thus control the creation and rupture of conducting filaments. The ReRAM device with an atomically thin interlayer of defective monolayer graphene reveals much reduced fluctuations in switching parameters compared to a conventional one. Our results demonstrate that defective monolayer graphene paves the way to reliable ReRAM devices operating under confined current path distribution.

  10. Markers/parameters for the evaluation of natural resistance status of small ruminants against gastrointestinal nematodes.

    PubMed

    Saddiqi, H A; Sarwar, M; Iqbal, Z; Nisa, M; Shahzad, M A

    2012-06-01

    The high prevalence of anthelmintic-resistant gastrointestinal nematodes (GINs) throughout the world has led to the need for alternative worm control strategies. One of the possible substitutes to reduce the problems of drug resistance and residue is the evaluation/breeding of small ruminants for greater resistance to the GINs (organically produced), which in turn would be a helpful tool to predict the performance of an animal. At present, the existing diversity in the genetic potential to resist/tolerate GINs infection both within and between breeds has been validated. Successful selection of animals to define the genotype and identified resistance is related to the employed markers. A number of phenotypic traits such as faecal egg count (FEC), worm burden, serum antibodies, peripheral eosinophilia, packed cell volume, live weight, serum protein and albumin concentrations have been used for this purpose both in natural and artificial infections. Relatively resistant/tolerant animals have also been found to have mastocytosis, globule leucocytes, high levels of histamine and immunoglobulin (Ig) A and IgE concentrations. Of these traits, the principal and most practical measurement used to assess resistance status in animals undergoing similar parasite challenges is FEC. FEC has a positive/negative correlation with other biochemical, cellular and immunological parameters; however, the reliability of individual trial is often questioned and valuable information regarding the genetic makeup can be obtained from pooled data of a large number of trials and parameters. This paper covers all the aspects reported in the literature on various parameters considered to evaluate the resistance status of a range of small ruminant breeds.

  11. [The regulatory-adaptive status in the evaluation of human stress-resistance].

    PubMed

    Pokrovskiĭ, V M; Mingalev, A N

    2012-01-01

    There was offered a method of human stress-resistance evaluation via the dynamics of the regulatory-adaptive status. The regulatory-adaptive status was being determined via the parameters of the cardiorespiratory synchronism in the original state and at the application of the stress factor. Individuals, whose regulatory-adaptive status didn't change or decreased by not more than 5-6% at the exposition to the stress factor formed the group with a high level of stress-resistance. The individuals, whose regulatory adaptive status at the exposition to the stress factor decreased by less than 50% formed a group with a moderate level of stress-resistance. The examinees, whose regulatory-adaptive status decreased by more than 50% in a response to the stress factor were set in a group with a low stress-resistance level. The method was tested in the three stress models: 1) exam stress-on 58 students; 2) parachute jump stress-on 35 beginner parachutists; 3) stress, caused by the relocation to the zone of the catastrophe on 30 rescuers. In all the three models the method is highly informative. At the same time the levels of the stress-resistance were being evaluated by the psychological methods. It was shown, that the evaluation of the stress-resistance level via the dynamics of the regulatory-adaptive status allows to objectively characterize the ability of an individual to resist stress and should be included in the test complex for the casting of the candidates for the extreme professions.

  12. Current tools available for the diagnosis of drug-resistant tuberculosis

    PubMed Central

    Gilpin, Christopher; Korobitsyn, A.; Weyer, K.

    2016-01-01

    Drug-resistant tuberculosis (DR-TB) poses a major threat to control of tuberculosis worldwide. Diagnosis and treatment of DR-TB are considerably more difficult than for drug-susceptible tuberculosis (TB) and require higher level infrastructure and proficiency from laboratory specialists and clinicians. The World Health Organization (WHO) End TB Strategy calls for early diagnosis and initiation of appropriate treatment of all persons of all ages with any form of drug-susceptible TB or DR-TB. This requires ensuring access to WHO-recommended rapid diagnostics and universal drug susceptibility testing (DST) for all persons with signs and symptoms of TB. There are a number of laboratory tools available for diagnosis of DR-TB, including phenotypic culture-based DST as well as molecular methods. Optimal and complementary use of the available diagnostic tools at the different levels of the tiered network of TB laboratories, as well as correct interpretation of the diagnostic results provided by them is critical for accurate and timely diagnosis of DR-TB thus enabling effective treatment and care of patients. PMID:28386407

  13. Current treatments and novel therapeutic targets for castration resistant prostate cancer with bone metastasis

    PubMed Central

    Wei, Juncheng; Wang, Zhilin; Makarov, Danil; Li, Xin

    2013-01-01

    Prostate cancer is a leading cause of cancer death in men in developed countries. While early stage disease can often be cured, many patients eventually develop castration resistant prostate cancer (CRPC). The majority of CRPC patients have bone metastases, which cause significant morbidity and mortality. Although there is no cure for prostate cancer metastatic to bone, several bone-targeted agents have been approved to prevent skeletal-related events (SREs). Among them, bisphosphonates were the first class of drugs investigated for prevention of SREs. Denosumab is a recently approved agent that binds to the receptor activator of nuclear factor-κB ligand (RANKL) as a humanized monoclonal antibody. Both agents target prostate cancer skeletal metastasis through the inhibition of bone resorption. Alpharadin is the first radiopharmaceutical agent that has significant overall survival benefit. It has benefits in pain palliation and SREs as well. Another newly approved drug is Abiraterone acetate, which decreases circulating levels of testosterone by targeting an enzyme expressed in the testis and the adrenal, as well as in prostate cancer tissues. This review outlines the clinical and preclinical data supporting the use of these and new agents in development for CRPC with bone metastasis. PMID:25374898

  14. Treatment-resistant schizophrenia: current insights on the pharmacogenomics of antipsychotics

    PubMed Central

    Lally, John; Gaughran, Fiona; Timms, Philip; Curran, Sarah R

    2016-01-01

    Up to 30% of people with schizophrenia do not respond to two (or more) trials of dopaminergic antipsychotics. They are said to have treatment-resistant schizophrenia (TRS). Clozapine is still the only effective treatment for TRS, although it is underused in clinical practice. Initial use is delayed, it can be hard for patients to tolerate, and clinicians can be uncertain as to when to use it. What if, at the start of treatment, we could identify those patients likely to respond to clozapine – and those likely to suffer adverse effects? It is likely that clinicians would feel less inhibited about using it, allowing clozapine to be used earlier and more appropriately. Genetic testing holds out the tantalizing possibility of being able to do just this, and hence the vital importance of pharmacogenomic studies. These can potentially identify genetic markers for both tolerance of and vulnerability to clozapine. We aim to summarize progress so far, possible clinical applications, limitations to the evidence, and problems in applying these findings to the management of TRS. Pharmacogenomic studies of clozapine response and tolerability have produced conflicting results. These are due, at least in part, to significant differences in the patient groups studied. The use of clinical pharmacogenomic testing – to personalize clozapine treatment and identify patients at high risk of treatment failure or of adverse events – has moved closer over the last 20 years. However, to develop such testing that could be used clinically will require larger, multicenter, prospective studies. PMID:27853387

  15. Evaluation tests of platinum resistance thermometers for a cryogenic wind tunnel application

    NASA Technical Reports Server (NTRS)

    Germain, E. F.; Compton, E. C.

    1984-01-01

    Thirty-one commercially designed platinum resistance thermometers were evaluated for applicability to stagnation temperature measurements between -190 C and +65 C in the Langley Research Center's National Transonic Facility. Evaluation tests included X-ray shadowgraphs, calibrations before and after aging, and time constant measurements. Two wire-wound low thermal mass probes of a conventional design were chosen as most suitable for this cryogenic wind tunnel application.

  16. Evaluation of edible ginger and turmeric cultivars for root-knot nematode resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Edible ginger and turmeric roots are important agricultural commodities for the State of Hawaii. Bacterial wilt, Ralstonia solanacearum, and root-knot nematodes, Meloidogyne spp. are major factors hindering optimum production. An evaluation of tolerance and resistance to M. incognita was undertake...

  17. Field Evaluation of Apple Rootstocks for Orchard Performance and Fire Blight Resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In 2002, apple rootstock trials using three scion cultivars were established at Geneva, NY to evaluate 64 apple (Malus X domestica) rootstocks for horticultural performance and fire blight resistance. Field trials compared several elite Geneva® apple rootstocks, which were bred for tolerance to fir...

  18. Ft. Collins sugar beet germplasm evaluated for rhizomania and storage rot resistance in Idaho, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fifty-seven sugar beet (Beta vulgaris L.) lines from the USDA-ARS Ft. Collins sugar beet program and four check cultivars were screened for resistance to Beet necrotic yellow vein virus (BNYVV), the causal agent of rhizomania, and storage rot. The rhizomania evaluation was conducted at the USDA-ARS...

  19. Evaluating Hawaii-Grown Papaya for Resistance to Internal Yellowing Disease Caused by Enterobacter cloacae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Papaya (Carica papaya L.) cultivars and breeding lines were evaluated for resistance to Enterobacter cloacae (Jordan) Hormaeche & Edwards, the bacterial causal agent of internal yellowing disease (IY), using a range of concentrations of the bacterium. Linear regression analysis was performed and IY ...

  20. Evaluation of the Ugandan sorghum accessions for grain mold and anthracnose resistance

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sorghum accessions from Uganda were evaluated for grain mold and anthracnose resistance during the 2005 and 2006 growing seasons at the Texas A&M University Research Farm, near College Station, TX. Accession PI534117 and SC719-11E exhibited the lowest grain mold severities of 2.4, whereas, accessio...

  1. Evaluation of Onion Genotypes for Resistance to Stunting Caused by Rhizoctonia solani AG 8

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A total of 35 onion genotypes was evaluated for resistance to onion stunting caused by Rhizoctonia solani anastomosis group 8 (AG-8) under temperature-controlled greenhouse conditions (15 ± 1oC) in 2013. Each onion genotype was planted in a cone-tainer with and without inoculation with R. solani AG ...

  2. Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 32 commercial cultivars were screened by growing them in a sugar beet field infested with B...

  3. Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 33 commercial cultivars were screened by growing them in a sugar beet field infested with B...

  4. Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 28 commercial cultivars were screened by growing them in a sugar beet field infested with B...

  5. Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 24 experimental cultivars were screened by growing them in a sugar beet field infested with...

  6. Commercial sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 28 commercial cultivars were screened by growing them in a sugar beet field infested with B...

  7. Experimental sugar beet cultivars evaluated for rhizomania resistance and storability in Idaho, 2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Rhizomania caused by Beet necrotic yellow vein virus (BNYVV) and storage losses are serious sugar beet production problems. To identify sugar beet cultivars with resistance to BNYVV and evaluate storability, 30 experimental cultivars were screened by growing them in a sugar beet field infested with...

  8. Evaluation of resistance to chinch bug in pearl millet in temperate and subtropical environments

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pearl millet [Pennisetum glaucum (L.) R. Br.] inbreds and hybrids were evaluated for resistance to chinch bug [Blissus leucopterus leucopterus (Say)] at Lincoln, NE and Tifton, GA in 2003 and 2004. Plant damage from insect feeding was assessed throughout the growing season. Differences plant mortali...

  9. Beta PIs from the USDA-ARS NPGS evaluated for resistance to Cercospora beticola, 2013

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty-one Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research and Extension Center near Frankenmuth, Michigan. Internal controls included a susceptibl...

  10. Beta PIs from the USDA-ARS NPGS evaluated for resistance to Cercospora beticola, 2012

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research and Extension Center near Frankenmuth, MI. Internal controls included a susceptible germplas...

  11. Beta PIs from the USDA-ARS NPGS evaluated for resistance to Cercospora beticola, 2014

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research and Extension Center near Frankenmuth, Michigan. Internal controls included a susceptible, '...

  12. Beta PIs from the USDA-ARS NPGS evaluated for resistance to Cercospora beticola, 2010

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research and Extension Center near Frankenmuth, MI. Internal controls included a susceptible commercia...

  13. Beta PIs from the USDA-ARS NPGS evaluated for resistance to Cercospora beticola, 2015

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research and Extension Center near Frankenmuth, MI. An additional seven entries resulting from crossi...

  14. Beta PIs from the USDA-ARS NPGS evaluated for resistance to Cercospora beticola, 2011

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research and Extension Center near Frankenmuth, MI. Internal controls included a susceptible commercia...

  15. Beta PIs From the USDA-ARS NPGS Evaluated for Resistance to Cercospora beticola, 2009

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Thirty Plant Introductions (PIs) from the USDA-ARS National Plant Germplasm System were evaluated for resistance to Cercospora beticola in an artificially produced epiphytotic at the Saginaw Valley Research Farm near Frankenmuth, MI. Internal controls included a susceptible commercial variety, CE, ...

  16. DC resistance comparison between a current comparator bridge and the quantum Hall system at Inmetro

    NASA Astrophysics Data System (ADS)

    da Silva, M. C.; Carvalho, H. R.; Vasconcellos, R. T. B.

    2016-07-01

    This paper presents a comparison results between the Quantum Hall System (QHS) under development at the Quantum Electrical Metrology Laboratory (Lameq) and the current comparator calibration system, traceable to the Bureau International des Poids et Mesures (BIPM), at the Electrical Standardization Metrology Laboratory (Lampe), both part of the Electrical Metrology Division, at Inmetro. Comparisons were performed with 1 Ω, 10 Ω, 100 Ω, 1 kΩ and 10 kΩ resistors. The results obtained over two years of work are presented here, showing that the comparison contributed to improve the calibration systems of both Lampe and Lameq.

  17. Non-Destructive Evaluation of Thermal Spray Coating Interface Quality by Eddy Current Method

    SciTech Connect

    B.Mi; X. Zhao; R. Bayles

    2006-05-26

    Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with different surface preparation conditions before applying the coating, e.g., grit-blasted surface, wire-brush cleaned surface, and a dirty surface. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that the three surface preparation conditions can be successfully differentiated by looking into the impedance difference observed from the eddy current probe. The measurement is fairly robust and consistent. More specimens are also prepared with variations of process parameters, such as spray angle, stand-off distance, and application of corrosion protective sealant, etc. They are blindly tested to evaluate the reliability of the eddy current system. Quantitative relations between the coating bond strength and the eddy current response are also established with the support of destructive testing. This non-contact, non-destructive, easy to use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.

  18. Selection, Placement and Instatement of School Managers in Turkey: Evaluation of the Current Situation

    ERIC Educational Resources Information Center

    Memisoglu, Salih Pasa

    2015-01-01

    The aim of this study is to evaluate the new regulations and current practices in terms of how they apply--to the selection, training and instatement of school administrators in Turkey. The successful implementation of Turkish National Development Plans is closely related to the knowledge and skills of managers working at various levels in every…

  19. Relationship between Counseling Students' Childhood Memories and Current Negative Self-Evaluations When Receiving Corrective Feedback

    ERIC Educational Resources Information Center

    Stroud, Daniel; Olguin, David; Marley, Scott

    2016-01-01

    This article entails a study focused on the relationship between counseling students' negative childhood memories of receiving corrective feedback and current negative self-evaluations when receiving similar feedback in counselor education programs. Participants (N = 186) completed the Corrective Feedback Instrument-Revised (CFI-R; Hulse-Killacky…

  20. Current Status of the Matson Evaluation of Drug Side Effects (MEDS)

    ERIC Educational Resources Information Center

    Matson, Johnny L.; Cervantes, Paige E.

    2013-01-01

    The Matson Evaluation of Drug Side Effects (MEDS) is currently the best established and most researched measure of drug side effects in the intellectual disability (ID) literature. Initial research was conducted on its psychometric properties such as reliability and validity. More recent research studies have used the measure to determine the…

  1. Current Evaluation of Upper Oesophageal Sphincter Opening in Dysphagia Practice: An International SLT Survey

    ERIC Educational Resources Information Center

    Regan, Julie; Walshe, Margaret; McMahon, Barry P.

    2012-01-01

    Background: The assessment of adequate upper oesophageal sphincter (UOS) opening during swallowing is an integral component of dysphagia evaluation. Aims: To ascertain speech and language therapists' (SLTs) satisfaction with current methods for assessing UOS function in people with dysphagia and to identify challenges encountered by SLTs with UOS…

  2. Evaluation of Pakistan wheat germplasms for stripe rust resistance using molecular markers.

    PubMed

    Sobia, Tabassum; Muhammad, Ashraf; Chen, XianMing

    2010-09-01

    Wheat production in Pakistan is seriously constrained due to rust diseases and stripe rust (yellow) caused by Puccinia striiformis f. sp. tritici, which could limit yields. Thus development and cultivation of genetically diverse and resistant varieties is the most sustainable solution to overcome these diseases. The first objective of the present study was to evaluate 100 Pakistan wheat cultivars that have been grown over the past 60 years. These cultivars were inoculated at the seedling stage with two virulent stripe rust isolates from the United States and two from Pakistan. None of the wheat cultivars were resistant to all tested stripe rust isolates, and 16% of cultivars were susceptible to the four isolates at the seedling stage. The data indicated that none of the Pakistan wheat cultivars contained either Yr5 or Yr15 genes that were considered to be effective against most P. striiformis f. sp. tritici isolates from around the world. Several Pakistan wheat cultivars may have gene Yr10, which is effective against isolate PST-127 but ineffective against PST-116. It is also possible that these cultivars may have other previously unidentified genes or gene combinations. The second objective was to evaluate the 100 Pakistan wheat cultivars for stripe rust resistance during natural epidemics in Pakistan and Washington State, USA. It was found that a higher frequency of resistance was present under field conditions compared with greenhouse conditions. Thirty genotypes (30% of germplasms) were found to have a potentially high temperature adult plant (HTAP) resistance. The third objective was to determine the genetic diversity in Pakistan wheat germplasms using molecular markers. This study was based on DNA fingerprinting using resistance gene analog polymorphism (RGAP) marker analysis. The highest polymorphism detected with RGAP primer pairs was 40%, 50% and 57% with a mean polymorphism of 36%. A total of 22 RGAP markers were obtained in this study. RGAP, simple

  3. Non-Destructive Evaluation of Thermal Spray Coating Interface Quality By Eddy Current Method

    SciTech Connect

    B. Mi; G. Zhao; R. Bayles

    2006-08-10

    Thermal spray coating is usually applied through directing molten or softened particles at very high velocities onto a substrate. An eddy current non-destructive inspection technique is presented here for thermal spray coating interface quality characterization. Several high-velocity-oxy-fuel (HVOF) coated steel plates were produced with various surface preparation conditions or spray process parameters. A quad-frequency eddy current probe was used to manually scan over the coating surface to evaluate the bonding quality. Experimental results show that different surface preparation conditions and varied process parameters can be successfully differentiated by the impedance value observed from the eddy current probe. The measurement is fairly robust and consistent. This non-contact, nondestructive, easy-to-use technique has the potential for evaluating the coating quality immediately after its application so that any defects can be corrected immediately.

  4. Evaluation of lung tumor response to therapy: Current and emerging techniques.

    PubMed

    Coche, E

    2016-10-01

    Lung tumor response to therapy may be evaluated in most instances by morphological criteria such as RECIST 1.1 on computed tomography (CT) or magnetic resonance imaging (MRI). However, those criteria are limited because they are based on tumoral dimensional changes and do not take into account other morphologic criteria such as density evaluation, functional or metabolic changes that may occur following conventional or targeted chemotherapy. New techniques such as dual-energy CT, PET-CT, MRI including diffusion-weighted MRI has to be considered into the new technical armamentarium for tumor response evaluation. Integration of all informations provided by the different imaging modalities has to be integrated and represents probably the future goal of tumor response evaluation. The aim of the present paper is to review the current and emerging imaging criteria used to evaluate the response of therapy in the field of lung cancer.

  5. Performance evaluation of high-temperature superconducting current leads for electric utility SMES systems

    NASA Astrophysics Data System (ADS)

    Niemann, R. C.; Cha, Y. S.; Hull, J. R.; Rey, C. M.; Dixon, K. D.

    As part of the U.S. Department of Energy's Superconductivity Technology Program, Argonne National Laboratory and Babcock & Wilcox are developing high-temperature super-conductor (HTS) current leads for application to electric utility superconducting magnetic energy storage systems. A 16,000-A HTS lead has been designed and is being constructed. An evaluation program for component performance was conducted to confirm performance predictions and/or to qualify the design features for construction. Performance of the current lead assemblies will be evaluated in a test program that includes assembly procedures, tooling, and quality assurance; thermal and electrical performance; and flow and mechanical characteristics. Results of the evaluations to date are presented.

  6. Multicenter Evaluation of Genechip for Detection of Multidrug-Resistant Mycobacterium tuberculosis

    PubMed Central

    Pang, Yu; Xia, Hui; Zhang, Zhiying; Li, Junchen; Dong, Yi; Li, Qiang; Ou, Xichao; Song, Yuanyuan; Wang, Yufeng; O'Brien, Richard; Kam, Kai Man; Chi, Junying; Huan, Shitong; Chin, Daniel P.

    2013-01-01

    Drug-resistant tuberculosis (TB), especially multidrug-resistant TB (MDR-TB), is still one of the most serious threats to TB control worldwide. Early diagnosis of MDR-TB is important for effectively blocking transmission and establishing an effective protocol for chemotherapy. Genechip is a rapid diagnostic method based on molecular biology that overcomes the poor biosafety, time consumption, and other drawbacks of traditional drug sensitivity testing (DST) that can detect MDR-TB. However, the Genechip approach has not been effectively evaluated, especially in limited-resource laboratories. In this study, we evaluated the performance of Genechip for MDR-TB in 1,814 patients in four prefectural or municipal laboratories and compared its performance with that of traditional DST. The results showed that the sensitivity and specificity of Genechip were 87.56% and 97.95% for rifampin resistance and 80.34% and 95.82% for isoniazid resistance, respectively. In addition, we found that the positive grade of the sputum smears influenced the judgment of results by Genechip. The test judged only 75% of the specimens of “scanty” positive grade. However, the positive grade of the specimens showed no influence on the accuracy of Genechip. Overall, the study suggests that, in limited-resource laboratories, Genechip showed high sensitivity and specificity for rifampin and isoniazid resistance, making it a more effective, rapid, safe, and cost-beneficial method worthy of broader use in limited-resource laboratories in China. PMID:23515537

  7. Evaluation of brilliance CRE agar for the detection of carbapenem-resistant gram-negative bacteria.

    PubMed

    Bracco, Silvia; Migliavacca, Roberta; Pini, Beatrice; Corbo, Nicoletta; Nucleo, Elisabetta; Brigante, Gioconda; Piazza, Aurora; Micheletti, Piero; Luzzaro, Francesco

    2013-04-01

    The aim of this work was to evaluate the performance of the new chromogenic medium BrillianceTM CREAgar (Thermo Fisher Scientific) for determining the limit of detection of carbapenem-resistant enterobacteria (CRE). A total of 70 clinical isolates were studied. Of these, 30 were well-characterized CRE, including Klebsiella pneumoniae strains producing KPC-, VIM-, and OXA-type enzymes, VIM-positive Enterobacter cloacae and Escherichia coli, NDM-positive E. coli, and enterobacterial isolates characterized by porin loss associated with ESBL production or AmpC hyperproduction. Ten carbapenem-resistant non-fermentative isolates were also included as well as 30 carbapenem-susceptible isolates. Carbapenem-resistant strains were inoculated at three different concentrations onto Brilliance CRE Agar (from 1.5x101 CFU/ml up to 1.5x104 CFU/ml) whereas carbapenem-susceptible isolates were inoculated at a concentration of 1.5x102 CFU/ml. The medium sustained the growth of carbapenem-resistant isolates, showing detection limits from 1.5x101 CFU/ml (in 31/40 cases) to 1.5x104 CFU/ml. No growth was observed with carbapenem-sensitive control strains. Our results indicate that the Brilliance CRE Agar allows the growth of carbapenem-resistant isolates with low detection limits and could represent a useful screening medium for both enterobacteria and non-fermentative Gram-negative strains resistant to carbapenems.

  8. Evaluation of Association of Hyperuricaemia with Metabolic Syndrome and Insulin Resistance

    PubMed Central

    Avula, Naveen Reddy

    2016-01-01

    Introduction The prevalence of Metabolic Syndrome (MetS) ranges from <10% to as much as 84% depending on region and composition of the population studied. The MetS is a growing public health problem in the world. Aim To evaluate association of hyperuricaemia with components of MetS and insulin resistance. Materials and Methods Sixty patients with MetS were conveniently recruited. MetS was defined as per Adult Treatment Panel III (ATP III) guidelines. For the purpose of analysis study participants were grouped into, group-I (controls - normal serum uric acid levels) and group-II (cases - hyperuricaemia). Hyperuricaemia was defined with cut-off >6.8mg/dl in both men and women. Associated work up for MetS and insulin resistance like fasting blood sugar, fasting lipid profile, fasting insulin, serum uric acid was done. Blood pressure and anthropometric measurements including weight, height and waist circumferences were measured and BMI was calculated. HOMA IR method was used to measure the degree of insulin resistance. Logistic regression analysis was used to evaluate association of hyperuricaemia with MetS and insulin resistance. Receiver Operating Curve (ROC) was plotted to find out optimum cut-off value for insulin resistance. Results A significant increase in systolic blood pressure (p < 0.001) and triglyceride levels (p=0.027) were observed in hyperuricaemia subjects when compared to controls. After adjusting for potential confounders, Insulin resistance (HOMA IR >3.4) was independently associated with hyperuricaemia (OR=5.79, 95% CI=1.6- 20.69, p=0.007). Conclusion Insulin resistance beyond a threshold is independently associated with hyperuricaemia in subjects with MetS. PMID:28208909

  9. Direct current (DC) resistivity and induced polarization (IP) monitoring of active layer dynamics at high temporal resolution

    NASA Astrophysics Data System (ADS)

    Doetsch, Joseph; Ingeman-Nielsen, Thomas; Christiansen, Anders V.; Fiandaca, Gianluca; Auken, Esben; Adamson, Kathryn; Lane, Timothy; Elberling, Bo

    2014-05-01

    With climatic changes, permafrost thawing and changes in active layer dynamics influencing microbial activity and greenhouse gas feedbacks to the climate system, understanding of the interaction between biogeochemical and thermal processes in the ground is of increasing interest. Here we present results of from an on-going field experiment, where the active layer dynamics are monitored using direct current (DC) resistivity and induced polarization (IP) measurements at high temporal resolution. These DC/IP measurements are supplemented by pore water analysis, continuous ground temperature monitoring (0-150 cm depth) and structural information from ground penetrating radar (GPR). The study site (N69°15', W53°30', 30 m a.s.l.) is located at a Vaccinium/Empetrum heath tundra area near the Arctic Station on Qeqertarsuaq on the west coast of Greenland. Mean air temperatures of the warmest (July) and the coldest (February-March) months are 7.1 and -16.0°C, respectively. The DC/IP monitoring system was installed in July 2013 and has since been acquiring at least 6 data sets per day on a 42-electrode profile with 0.5 m electrode spacing. Recorded data include DC resistivity, stacked full-decay IP responses and full waveform data at 1 kHz sampling frequency. The monitoring system operates fully automatic and data are backed up locally and uploaded to a web server. Time-lapse DC resistivity inversions of data acquired during the freezing period of October - December 2013 clearly image the soil freezing as a strong increase in resistivity. While the freezing horizon generally moves deeper with time, some variations in the freezing depth are observed along the profile. Comparison with soil temperature measurements at different depths indicates a linear relationship between the logarithm of electrical resistivity and temperature. Preliminary time-lapse inversions of the full-decay induced polarization (IP) data indicate a decrease of chargeability with freezing of the ground

  10. Evaluation of efflux pumps gene expression in resistant Pseudomonas aeruginosa isolates in an Iranian referral hospital

    PubMed Central

    Pourakbari, Babak; Yaslianifard, Sahar; Yaslianifard, Somaye; Mahmoudi, Shima; Keshavarz-Valian, Sepideh; Mamishi, Setareh

    2016-01-01

    Background and Objectives: Pseudomonas aeruginosa (PA) is one of the most important causes of nosocomial infections and has an intrinsic resistance to many antibiotics. Among all the resistance-nodulation-division (RND) pumps of P. aeruginosa, MexAB-OprM is the first efflux pump found to target multiple classes of antibiotics. This study was aimed to evaluate the expression level of genes expressing MexAB-OprM in clinical isolates of P. aeruginosa. Materials and Methods: In this study, 45 P. aeruginosa strains were isolated from patients admitted to Children’s Medical Center Hospital, an Iranian referral hospital. Disk diffusion and Minimum Inhibitory Concentration (MIC) methods were used for determination of the patterns of resistance to antibiotics. Real-time PCR was used to investigate the expression level of genes of MexAB-OprM efflux pump. Results: Among 45 resistant PA isolates, the frequency of genes overexpression was as follows: MexA (n=25, 55.5%), MexB (n=24, 53.3%) and OprM (n=16, 35.5%). In addition, in 28 strains (62%) overexpression was observed in one of the studied three genes of MexAB-OprM efflux pump. Conclusion: In our study 28 isolates (62%) had increased expression level of efflux pumps genes, MexAB-OprM. Although the efflux pumps play important roles in increasing the resistance towards different antibiotics but the role of other agents and mechanisms in evolution of resistance should not be ignored. Since the concomitant overproduction of other Mex efflux systems might have additive effects on antibiotic resistance, the co-expressing of a multicomponent efflux pump is recommended. On the other hand, the concomitant overproduction of two Mex pumps might have additive effects on resistance to antibiotic. Therefore co-expressing of Mex efflux systems is recommended. PMID:28210464

  11. Evaluation of determination methods of the Si/Al contact resistance of screen-printed passivated emitter and rear solar cells

    NASA Astrophysics Data System (ADS)

    Müller, M.; Lottspeich, F.

    2014-02-01

    The Si/Al contact resistance of narrow p-type contact areas of crystalline silicon solar cells is a crucial parameter for the further development and improvement of passivated emitter and rear (PERC) solar cells. In this paper, two methods for determining the rear contact resistance are analyzed and improved: the series resistance analysis and the transfer length method (TLM). We use an experimental set of PERC solar cells with varying metallization fraction, and we analyze the experiment using numerical device simulation. In the first method, the resistive losses are extracted from the I-V-curves of the PERC cells, and the rear contact resistance is separated by subtracting the analytically calculated base contribution. The state-of-the-art analytical calculations deviate significantly from our numerical simulations, causing a high level of uncertainty that we do not recommend this method (an upper limit of the rear contact resistance per line contact is determined to be about 2 Ω cm). In the second method, the rear line contacts are separated and measured with the TLM. Still, the series resistance loss in the base has to be quantified considering a thick base and the rear line contact geometry. We separate the base component by numerical device simulations and find that the rear contact resistance per line contact is below 0.5 Ω cm. This implies that rear contact resistance reduces cell efficiency of screen-printed PERC solar cells only by about 0.1%abs for metallization fractions higher than 3.5%, i.e., the rear contact resistance is currently no significant loss mechanism in our PERC solar cells. All of our improved evaluations lead to lower resistance values than previously reported and with a reduced uncertainty. The TLM method is suggested to be favorable.

  12. Performance Evaluation and Modeling of Erosion Resistant Turbine Engine Thermal Barrier Coatings

    NASA Technical Reports Server (NTRS)

    Miller, Robert A.; Zhu, Dongming; Kuczmarski, Maria

    2008-01-01

    The erosion resistant turbine thermal barrier coating system is critical to the rotorcraft engine performance and durability. The objective of this work was to determine erosion resistance of advanced thermal barrier coating systems under simulated engine erosion and thermal gradient environments, thus validating a new thermal barrier coating turbine blade technology for future rotorcraft applications. A high velocity burner rig based erosion test approach was established and a new series of rare earth oxide- and TiO2/Ta2O5- alloyed, ZrO2-based low conductivity thermal barrier coatings were designed and processed. The low conductivity thermal barrier coating systems demonstrated significant improvements in the erosion resistance. A comprehensive model based on accumulated strain damage low cycle fatigue is formulated for blade erosion life prediction. The work is currently aiming at the simulated engine erosion testing of advanced thermal barrier coated turbine blades to establish and validate the coating life prediction models.

  13. Corrosion resistance evaluation of Pd-free Ag-Au-Pt-Cu dental alloys.

    PubMed

    Fujita, Takeshi; Shiraishi, Takanobu; Takuma, Yasuko; Hisatsune, Kunihiro

    2011-01-01

    The corrosion resistance of nine experimental Pd-free Ag-Au-Pt-Cu dental alloys in a 0.9% NaCl solution was investigated using cyclic voltammetry (CV), optical microscopy, and scanning electron microscopy (SEM). CV measurements revealed that the breakdown potential (E(bd)) and zero current potential (E(zc)) increased with increasing Au/(Au+Ag) atomic ratio. Thus, the Au/(Au+Ag) atomic ratio, but not the Cu content, influenced the corrosion resistance of Ag-Au-Pt-Cu alloys. After the forward scan of CV, both optical and scanning electron microscope images showed that in all the experimental alloys, the matrix phase was corroded but not the second phase. From corrosion resistance viewpoint, the Ag-Au-Pt-Cu alloys seemed to be suitable for clinical application.

  14. [Changes in cortical neuron input resistance and the stimulation threshold of its electroexcitable membrane by a depolarizing current during the habituation process].

    PubMed

    Pivovarov, A S; Gusel'nikov, V I

    1979-01-01

    The habituation of neurones in the turtle visual cortex is accompanied by changes in their input resistance and in the threshold of stimulation of their electro-excitable membrane by depolarizing current. Input resistance of the neurone during monotoneous stimulation decreases throughout habituation and increases following an alien stimulus. The threshold becomes higher if the current acts as a monotoneous stimulus and gets lower if it acts as an alien stimulus. Input resistance of a habituated neurone and its threshold are restored after alien stimulation and spontaneously--after interruption. These changes are specific to the stimulation, appear during its action, and are reversible. They form postsynaptic mechanisms of habituation.

  15. 50 MHz-10 GHz low-power resistive feedback current-reuse mixer with inductive peaking for cognitive radio receiver.

    PubMed

    Vitee, Nandini; Ramiah, Harikrishnan; Chong, Wei-Keat; Tan, Gim-Heng; Kanesan, Jeevan; Reza, Ahmed Wasif

    2014-01-01

    A low-power wideband mixer is designed and implemented in 0.13 µm standard CMOS technology based on resistive feedback current-reuse (RFCR) configuration for the application of cognitive radio receiver. The proposed RFCR architecture incorporates an inductive peaking technique to compensate for gain roll-off at high frequency while enhancing the bandwidth. A complementary current-reuse technique is used between transconductance and IF stages to boost the conversion gain without additional power consumption by reusing the DC bias current of the LO stage. This downconversion double-balanced mixer exhibits a high and flat conversion gain (CG) of 14.9 ± 1.4 dB and a noise figure (NF) better than 12.8 dB. The maximum input 1-dB compression point (P1dB) and maximum input third-order intercept point (IIP3) are -13.6 dBm and -4.5 dBm, respectively, over the desired frequency ranging from 50 MHz to 10 GHz. The proposed circuit operates down to a supply headroom of 1 V with a low-power consumption of 3.5 mW.

  16. 50 MHz–10 GHz Low-Power Resistive Feedback Current-Reuse Mixer with Inductive Peaking for Cognitive Radio Receiver

    PubMed Central

    Reza, Ahmed Wasif

    2014-01-01

    A low-power wideband mixer is designed and implemented in 0.13 µm standard CMOS technology based on resistive feedback current-reuse (RFCR) configuration for the application of cognitive radio receiver. The proposed RFCR architecture incorporates an inductive peaking technique to compensate for gain roll-off at high frequency while enhancing the bandwidth. A complementary current-reuse technique is used between transconductance and IF stages to boost the conversion gain without additional power consumption by reusing the DC bias current of the LO stage. This downconversion double-balanced mixer exhibits a high and flat conversion gain (CG) of 14.9 ± 1.4 dB and a noise figure (NF) better than 12.8 dB. The maximum input 1-dB compression point (P1dB) and maximum input third-order intercept point (IIP3) are −13.6 dBm and −4.5 dBm, respectively, over the desired frequency ranging from 50 MHz to 10 GHz. The proposed circuit operates down to a supply headroom of 1 V with a low-power consumption of 3.5 mW. PMID:25133252

  17. Evaluation of a diverse red clover collection for clover rot resistance (Sclerotinia trifoliorum).

    PubMed

    Vleugels, T; Baert, J; Van Bockstaele, E

    2013-01-01

    Sclerotinia trifoliorum Erikks. causes clover rot (clover cancer, Sclerotinia crown and root rot), an important disease in European red clover crops (Trifolium pratense L). The fungus infects plants in autumn through ascospores and entire fields can be destroyed by early spring. Although previous studies have evaluated various red clover populations for clover rot resistance, screening was often performed with one local isolate on just a few local varieties, often cultivars. Until today, no large collections of diverse red clover accessions have been screened. In this study, we studied the variation in clover rot susceptibility among 122 red clover accessions, including 85 accessions from the NPGS-USDA core collection. Cultivars (both diploid and tetraploid), landraces and wild accessions were included and different S. trifoliorum isolates were used. In a field experiment, plant yield, branching and susceptibility to mildew, rust and virus disease were scored for 122 red clover accessions. A similar collection of germplasm was screened for clover rot resistance by a bio-test on young plants using a mixture of five aggressive S. trifoliorum isolates. The effects of the variety type, ploidy level, growth habit, resistance to other diseases and levels of isoflavones (available for the NPGS-USDA collection) on clover rot susceptibility were determined. Possible sources of resistance were identified. Our red clover accessions differed significantly in susceptibility but no accession was completely resistant Three accessions (Maro, Tedi and No. 292) were significantly less susceptible than the other accessions. Intensive branching or a prostrate growth habit did not render plants more resistant. Accessions resistant to mildew or viruses were not more resistant to clover rot and accessions with high levels of isoflavones were not better protected against clover rot. On the other hand, tetraploid cultivars were on average 10% less susceptible than diploid cultivars

  18. Antimicrobial resistance in Salmonella enterica serovar typhi and paratyphi in South Asia-current status, issues and prospects.

    PubMed

    Akhtar, Saeed; Sarker, Mahfuzur R; Jabeen, Kausar; Sattar, Ahsan; Qamar, Aftab; Fasih, Naima

    2015-01-01

    The human race owes a debt of gratitude to antimicrobial agents, penicillin and its successors that have saved people from tremendous pain and suffering in the last several decades. Unfortunately, this consideration is no more true, as millions of people are prone to the challenging threat of emergence of antimicrobial resistance worldwide and the menace is more distressing in developing countries. Comparable with other bacterial species, Salmonella enterica serovar Typhi (S. typhi) and Paratyphi (S. paratyphi) have been evolving multidrug resistance (MDR) against a wide array of antibiotics, including chloramphenicol, ampicillin and co-trimoxazole, and globally affecting 21 million people with 220,000 deaths each year. S. typhi and S. paratyphi infections are also endemic in South Asia and a series of antibiotics used to treat these infections, have been losing efficacy against enteric fever. Currently, quinolones are regarded as a choice to treat MDR Salmonella in these regions. Travel-related cases of enteric fever, especially from South Asian countries are the harbinger of the magnitude of MDR Salmonella in that region. Conclusively, the MDR will continue to grow and the available antimicrobial agents would become obsolete. Therefore, a radical and aggressive approach in terms of rational use of antibiotics during treating infections is essentially needed.

  19. Antidepressant monotherapy and combination of antidepressants in the treatment of resistant depression in current clinical practice: A retrospective study.

    PubMed

    Bares, Martin; Novak, Tomas; Kopecek, Miloslav; Stopkova, Pavla; Höschl, Cyril

    2010-11-01

    Abstract Objectives. The aim of this study was to compare efficacy of antidepressant monotherapies and combinations of antidepressants in the treatment of resistant patients in current clinical practice. Methods. We reviewed chart documents of resistant depressive inpatients treated at least 4 weeks with a new treatment. Depressive symptoms and clinical status were assessed using Montgomery and Åsberg Depression Rating Scale (MADRS), Beck Depression Inventory-Short Form and Clinical Global Impression at the baseline, week 2 and in the end of treatment. Results. We identified 81 patients (27 with combinations and 51 with monotherapies) that were suitable for analyses. The combination group achieved higher reduction of MADRS score (14.6 vs 10.2 pts., p=0.02) and response rate (≥ 50% reduction of MADRS, 67% vs 39%, p=0.03). Number needed to treat for response was 4. Conclusions. Based on our results, we suggest that combination of antidepressants might be more effective than monotherapy in clinical practice.

  20. Evaluation of physico-mechanical properties of clayey soils using electrical resistivity imaging technique

    NASA Astrophysics Data System (ADS)

    Kibria, Golam

    Resistivity imaging (RI) is a promising approach to obtaining continuous profile of soil subsurface. This method offers simple technique to identify moisture variation and heterogeneity of the investigated area. However, at present, only qualitative information of subsurface can be obtained using RI. A study on the quantification of geotechnical properties has become important for rigorous use of this method in the evaluation of geohazard potential and construction quality control of landfill liner system. Several studies have been performed to describe electrical resistivity of soil as a function of pore fluid conductivity and surface conductance. However, characterization tests on pore water and surface charge are not typically performed in a conventional geotechnical investigation. The overall objective of this study is to develop correlations between geotechnical parameters and electrical resistivity of soil, which would provide a mean to estimate geotechnical properties from RI. As a part of the study, multiple regression analyses were conducted to develop practically applicable models correlating resistivity with influential geotechnical parameters. The soil samples considered in this study were classified as highly plastic clay (CH) and low plasticity clay (CL) according to Unified Soil Classification System (USCS). Based on the physical tests, scanning electron microscope (SEM), and energy dispersive X-ray spectroscopy (EDS) analysis, kaolinite was identified as the dominant mineral with some traces of magnesium, calcium, potassium, and iron. Electrical resistivity tests were conducted on compacted clays and undisturbed samples under varied geotechnical conditions. The experimental results indicated that the degree of saturation substantially influenced electrical resistivity. Electrical resistivity decreased as much as 11 times from initial value for the increase of degree of saturation from 23 to 100% in the laboratory tests on compacted clays. In case of

  1. Neural network evaluation of tokamak current profiles for real time control

    NASA Astrophysics Data System (ADS)

    Wróblewski, Dariusz

    1997-02-01

    Active feedback control of the current profile, requiring real-time determination of the current profile parameters, is envisioned for tokamaks operating in enhanced confinement regimes. The distribution of toroidal current in a tokamak is now routinely evaluated based on external (magnetic probes, flux loops) and internal (motional Stark effect) measurements of the poloidal magnetic field. However, the analysis involves reconstruction of magnetohydrodynamic equilibrium and is too intensive computationally to be performed in real time. In the present study, a neural network is used to provide a mapping from the magnetic measurements (internal and external) to selected parameters of the safety factor profile. The single-pass, feedforward calculation of output of a trained neural network is very fast, making this approach particularly suitable for real-time applications. The network was trained on a large set of simulated equilibrium data for the DIII-D tokamak. The database encompasses a large variety of current profiles including the hollow current profiles important for reversed central shear operation. The parameters of safety factor profile (a quantity related to the current profile through the magnetic field tilt angle) estimated by the neural network include central safety factor, q0, minimum value of q, qmin, and the location of qmin. Very good performance of the trained neural network both for simulated test data and for experimental datais demonstrated.

  2. Neural network evaluation of tokamak current profiles for real time control

    SciTech Connect

    Wroblewski, D.

    1997-02-01

    Active feedback control of the current profile, requiring real-time determination of the current profile parameters, is envisioned for tokamaks operating in enhanced confinement regimes. The distribution of toroidal current in a tokamak is now routinely evaluated based on external (magnetic probes, flux loops) and internal (motional Stark effect) measurements of the poloidal magnetic field. However, the analysis involves reconstruction of magnetohydrodynamic equilibrium and is too intensive computationally to be performed in real time. In the present study, a neural network is used to provide a mapping from the magnetic measurements (internal and external) to selected parameters of the safety factor profile. The single-pass, feedforward calculation of output of a trained neural network is very fast, making this approach particularly suitable for real-time applications. The network was trained on a large set of simulated equilibrium data for the DIII-D tokamak. The database encompasses a large variety of current profiles including the hollow current profiles important for reversed central shear operation. The parameters of safety factor profile (a quantity related to the current profile through the magnetic field tilt angle) estimated by the neural network include central safety factor, {ital q}{sub 0}, minimum value of {ital q}, {ital q}{sub min}, and the location of {ital q}{sub min}. Very good performance of the trained neural network both for simulated test data and for experimental datais demonstrated. {copyright} {ital 1997 American Institute of Physics.}

  3. Neural network evaluation of tokamak current profiles for real time control (abstract)

    SciTech Connect

    Wroblewski, D.

    1997-01-01

    Active feedback control of the current profile, requiring real-time determination of the current profile parameters, is envisioned for tokamaks operating in enhanced confinement regimes. The distribution of toroidal current in a tokamak is now routinely evaluated based on external (magnetic probes, flux loops) and internal (motional Stark effect) measurements of the poloidal magnetic field. However, the analysis involves reconstruction of magnetohydrodynamic equilibrium and is too intensive computationally to be performed in real time. In the present study, a neural network is used to provide a mapping from the magnetic measurements (internal and external) to selected parameters of the safety factor profile. The single-pass, feedforward calculation of output of a trained neural network is very fast, making this approach particularly suitable for real-time applications. The network was trained on a large set of simulated equilibrium data for the DIII-D tokamak. The database encompasses a large variety of current profiles including the hollow current profiles important for reversed central shear operation. The parameters of safety factor profile (a quantity related to the current profile through the magnetic field tilt angle) estimated by the neural network include central safety factor, q{sub 0}, minimum value of q, q{sub min}, and the location of q{sub min}. Very good performance of the trained neural network both for simulated test data and for experimental data is demonstrated. {copyright} {ital 1997 American Institute of Physics.}

  4. Neural network evaluation of tokamak current profiles for real time control (abstract)

    NASA Astrophysics Data System (ADS)

    Wróblewski, Dariusz

    1997-01-01

    Active feedback control of the current profile, requiring real-time determination of the current profile parameters, is envisioned for tokamaks operating in enhanced confinement regimes. The distribution of toroidal current in a tokamak is now routinely evaluated based on external (magnetic probes, flux loops) and internal (motional Stark effect) measurements of the poloidal magnetic field. However, the analysis involves reconstruction of magnetohydrodynamic equilibrium and is too intensive computationally to be performed in real time. In the present study, a neural network is used to provide a mapping from the magnetic measurements (internal and external) to selected parameters of the safety factor profile. The single-pass, feedforward calculation of output of a trained neural network is very fast, making this approach particularly suitable for real-time applications. The network was trained on a large set of simulated equilibrium data for the DIII-D tokamak. The database encompasses a large variety of current profiles including the hollow current profiles important for reversed central shear operation. The parameters of safety factor profile (a quantity related to the current profile through the magnetic field tilt angle) estimated by the neural network include central safety factor, q0, minimum value of q, qmin, and the location of qmin. Very good performance of the trained neural network both for simulated test data and for experimental data is demonstrated.

  5. Evaluation of stainless steel cladding for use in current design LWRs. Final report

    SciTech Connect

    Strasser, A.; Santucci, J.; Lindquist, K.; Yario, W.; Stern, G.; Goldstein, L.; Joseph, L.

    1982-12-01

    The design of stainless steel-clad LWR fuel and its performance at steady-state, transient, and accident conditions were reviewed. The objective was to evaluate the potential benefits and disadvantages of substituting stainless steel-clad fuel for the currently used Zircaloy-clad fuel. For a large, modern PWR, the technology and the fuel-cycle costs of stainless steel- and Zircaloy-clad fuels were compared.

  6. Ozone inactivation of resistant microorganisms: Laboratory analysis and evaluation of the efficiency of plants.

    PubMed

    Talbot, Pauline; Martinelli, Laure; Talvy, Samuel; Chauveheid, Eric; Haut, Benoît

    2012-11-15

    In this work, the ozone inactivation of resistant microorganisms is studied and a method to assess the efficiency of a drinking water plant to inactivate resistant microorganisms using ozone is proposed. This method aims at computing the fraction of resistant microorganisms that are not inactivated at the exit of an ozonation step by evaluating the duration of the lag phase of the ozone inactivation of these microorganisms and the contact time distribution of these microorganisms with the ozone in the step. To evaluate the duration of the lag phase of the ozone inactivation of resistant pathogenic microorganisms, an experimental procedure is proposed and applied to Bacillus subtilis spores. The procedure aims at characterizing the ozone inactivation kinetics of B. subtilis spores for different temperature and ozone concentration conditions. From experimental data, a model of the ozone inactivation of B. subtilis spores is built. One of the parameters of this model is called the lag time and it measures the duration of the lag phase of the ozone inactivation of B. subtilis spores. This lag time is identified for different temperature and ozone concentration conditions in order to establish a correlation between this lag time and the temperature and ozone concentration conditions. To evaluate the contact time distribution between microorganisms and the ozone in a disinfection step of a drinking water plant, a computational fluid dynamics tool is used. The proposed method is applied to the ozonation channel of an existing drinking water plant located in Belgium and operated by Vivaqua. Results show that lag times and contact times are both in the same order of magnitude of a few minutes. For a large range of temperatures and ozone concentrations in the Tailfer ozonation channel and for the highest hydraulic flow rate applied, a significant fraction of resistant microorganisms similar to B. subtilis spores is not inactivated.

  7. Quantitative image analysis for evaluating the abrasion resistance of nanoporous silica films on glass

    NASA Astrophysics Data System (ADS)

    Nielsen, Karsten H.; Karlsson, Stefan; Limbach, Rene; Wondraczek, Lothar

    2015-12-01

    The abrasion resistance of coated glass surfaces is an important parameter for judging lifetime performance, but practical testing procedures remain overly simplistic and do often not allow for direct conclusions on real-world degradation. Here, we combine quantitative two-dimensional image analysis and mechanical abrasion into a facile tool for probing the abrasion resistance of anti-reflective (AR) coatings. We determine variations in the average coated area, during and after controlled abrasion. Through comparison with other experimental techniques, we show that this method provides a practical, rapid and versatile tool for the evaluation of the abrasion resistance of sol-gel-derived thin films on glass. The method yields informative data, which correlates with measurements of diffuse reflectance and is further supported by qualitative investigations through scanning electron microscopy. In particular, the method directly addresses degradation of coating performance, i.e., the gradual areal loss of antireflective functionality. As an exemplary subject, we studied the abrasion resistance of state-of-the-art nanoporous SiO2 thin films which were derived from 5-6 wt% aqueous solutions of potassium silicates, or from colloidal suspensions of SiO2 nanoparticles. It is shown how abrasion resistance is governed by coating density and film adhesion, defining the trade-off between optimal AR performance and acceptable mechanical performance.

  8. Evaluation of the resistance of a geopolymer-based drug delivery system to tampering.

    PubMed

    Cai, Bing; Engqvist, Håkan; Bredenberg, Susanne

    2014-04-25

    Tamper-resistance is an important property of controlled-release formulations of opioid drugs. Tamper-resistant formulations aim to increase the degree of effort required to override the controlled release of the drug molecules from extended-release formulations for the purpose of non-medical use. In this study, the resistance of a geopolymer-based formulation to tampering was evaluated by comparing it with a commercial controlled-release tablet using several methods commonly used by drug abusers. Because of its high compressive strength and resistance to heat, much more effort and time was required to extract the drug from the geopolymer-based formulation. Moreover, in the drug-release test, the geopolymer-based formulation maintained its controlled-release characteristics after milling, while the drug was released immediately from the milled commercial tablets, potentially resulting in dose dumping. Although the tampering methods used in this study does not cover all methods that abuser could access, the results obtained by the described methods showed that the geopolymer matrix increased the degree of effort required to override the controlled release of the drug, suggesting that the formulation has improved resistance to some common drug-abuse tampering methods. The geopolymer matrix has the potential to make the opioid product less accessible and attractive to non-medical users.

  9. Quantitative image analysis for evaluating the abrasion resistance of nanoporous silica films on glass

    PubMed Central

    Nielsen, Karsten H.; Karlsson, Stefan; Limbach, Rene; Wondraczek, Lothar

    2015-01-01

    The abrasion resistance of coated glass surfaces is an important parameter for judging lifetime performance, but practical testing procedures remain overly simplistic and do often not allow for direct conclusions on real-world degradation. Here, we combine quantitative two-dimensional image analysis and mechanical abrasion into a facile tool for probing the abrasion resistance of anti-reflective (AR) coatings. We determine variations in the average coated area, during and after controlled abrasion. Through comparison with other experimental techniques, we show that this method provides a practical, rapid and versatile tool for the evaluation of the abrasion resistance of sol-gel-derived thin films on glass. The method yields informative data, which correlates with measurements of diffuse reflectance and is further supported by qualitative investigations through scanning electron microscopy. In particular, the method directly addresses degradation of coating performance, i.e., the gradual areal loss of antireflective functionality. As an exemplary subject, we studied the abrasion resistance of state-of-the-art nanoporous SiO2 thin films which were derived from 5–6 wt% aqueous solutions of potassium silicates, or from colloidal suspensions of SiO2 nanoparticles. It is shown how abrasion resistance is governed by coating density and film adhesion, defining the trade-off between optimal AR performance and acceptable mechanical performance. PMID:26656260

  10. Evaluation of powdery mildew-resistance of grape germplasm and rapid amplified polymorphic DNA markers associated with the resistant trait in Chinese wild Vitis.

    PubMed

    Zhang, J; Zhang, Y; Yu, H; Wang, Y

    2014-05-09

    The resistance of wild Vitis germplasm, including Chinese and American wild Vitis and Vitis vinifera cultivars, to powdery mildew (Uncinula necator Burr.) was evaluated for two consecutive years under natural conditions. Most of the Chinese and North American species displayed a resistant phenotype, whereas all of the European species were highly susceptible. The Alachua and Conquistador accessions of Vitis rotundifolia species, which originated in North America, were immune to the disease, while Baihe-35-1, one of the accessions of Vitis pseudoreticulata, showed the strongest resistance among all Chinese accessions evaluated. Three rapid amplified polymorphic DNA (RAPD) markers, OPW02-1756, OPO11-964, and OPY13-661, were obtained after screening 520 random primers among various germplasm, and these markers were found to be associated with powdery mildew resistance in Baihe-35-1 and in some Chinese species, but not in any European species. Analysis of F₁ and F₂ progenies of a cross between resistant Baihe-35-1 and susceptible Carignane (V. vinifera) revealed that the three RAPD markers were linked to the powdery resistant trait in Baihe-35-1 plants. Potential applications of the identified RAPD markers for gene mapping, marker-assisted selection, and breeding were investigated in 168 F₂ progenies of the same cross. Characterization of the resistant phenotype of the selected F₂ seedlings for breeding a new disease-resistant grape cultivar is in progress.

  11. Phenotypic and molecular evaluation of cotton hairy roots as a model system for studying nematode resistance.

    PubMed

    Wubben, Martin J; Callahan, Franklin E; Triplett, Barbara A; Jenkins, Johnie N

    2009-09-01

    Agrobacterium rhizogenes-induced cotton (Gossypium hirsutum L.) hairy roots were evaluated as a model system for studying molecular cotton-nematode interactions. Hairy root cultures were developed from the root-knot nematode (RKN) (Meloidogyne incognita [Kofoid and White] Chitwood, race 3)-resistant breeding line M315 and from the reniform nematode (RN) (Rotylenchulus reniformis Linford & Oliveira)-resistant accession GB713 (G. barbadense L.) and compared to a nematode-susceptible culture derived from the obsolete cultivar DPL90. M315, GB713, and DPL90 hairy roots differed significantly in their appearance and growth potential; however, these differences were not correlated with transcript levels of the A. rhizogenes T-DNA genes rolB and aux2 which help regulate hairy root initiation and proliferation. DPL90 hairy roots were found to support both RKN and RN reproduction in tissue culture, whereas M315 and GB713 hairy roots were resistant to RKN and RN, respectively. M315 hairy roots showed constitutive up-regulation of the defense gene MIC3 (Meloidogyne Induced Cotton3) compared to M315 whole-plant roots and DPL90 hairy roots. Our data show the potential use of cotton hairy roots in maintaining monoxenic RKN and RN cultures and suggest hairy roots may be useful in evaluating the effect of manipulated host gene expression on nematode resistance in cotton.

  12. The Evaluation of Methicillin Resistance in Staphylococcus aboard the International Space Station

    NASA Technical Reports Server (NTRS)

    Ott, C. M.; Bassinger, V. J.; Fontenot, S. L.; Castro, V. A.; Pierson, D. L.

    2005-01-01

    The International Space Station (ISS) represents a semi-closed environment with a high level of crewmember interaction. As community-acquired methicillin-resistant Staphylococcus aureus (MRSA) has emerged as a health concern in environments with susceptible hosts in close proximity, an evaluation of isolates of clinical and environmental Staphylococcus aureus and coagulase negative Staphylococcus was performed to determine if this trend was also present in astronauts aboard ISS or the space station itself. Rep-PCR fingerprinting analysis of archived ISS isolates confirmed our earlier studies indicating a transfer of S. aureus between crewmembers. In addition, this fingerprinting also indicated a transfer between crewmembers and their environment. While a variety of S. aureus were identified from both the crewmembers and the environment, phenotypic evaluations indicated minimal methicillin resistance. However, positive results for the Penicillin Binding Protein, indicative of the presence of the mecA gene, were detected in multiple isolates of archived Staphylococcus epidermidis and Staphylococcus haemolyticus. Phenotypic analysis of these isolates confirmed their resistance to methicillin. While MRSA has not been isolated aboard ISS, the potential exists for the transfer of the gene, mecA, from coagulase negative environmental Staphylococcus to S. aureus creating MRSA strains. This study suggests the need to expand environmental monitoring aboard long duration exploration spacecraft to include antibiotic resistance profiling.

  13. Impact of enzalutamide on patient-related outcomes in metastatic castration-resistant prostate cancer: current perspectives

    PubMed Central

    Luo, Jia; Graff, Julie N

    2016-01-01

    Prostate cancer claims the lives of more than 25,000 men in the United States yearly, most from metastatic disease. In the past decade, several new medications have been approved for the treatment of metastatic prostate cancer including the antiandrogen enzalutamide. In addition, there has been mounting interest in evaluating health-related quality of life (QoL) in patients with cancer including new more detailed recommendations released by the Prostate Cancer Working Group 3 on how to evaluate patient-related outcomes in clinical trials. A total of four randomized double-blind placebo-controlled trials have evaluated patients with metastatic castration-resistant prostate cancer (mCRPC) randomized to receive enzalutamide vs control or bicalutamide. Each study used validated health-related QoL and pain surveys to evaluate patient-related outcomes. The studies suggest that patients with mCRPC, including those aged 75 years and older, have favorable overall QoL scores taking enzalutamide compared to standard of care. There was short-term improved pain control in patients taking enzalutamide compared to those in the placebo group. Some commonly reported adverse effects included fatigue, back pain, and hot flashes. These studies were limited in their patient attrition in filling out surveys as well as difficulty in comparing them to each other. Future studies examining patients with mCRPC taking enzalutamide will have to rigorously standardize ways patient-reported outcomes are collected and evaluate patients in a more diversified real-world population. PMID:27942507

  14. Evaluation of eddy-current probe signals due to cracks in ferromagnetic parts of fast reactor

    NASA Astrophysics Data System (ADS)

    Wu, Tao; Bowler, John R.

    2017-02-01

    Eddy current testing to evaluate the condition of metallic parts in a sodium cooled fast reactor under standby conditions is challenging due to the presence of liquid sodium at 250 °C. The eddy current test system should be sensitive enough to capture small signal changes and hence an advanced inspection systems is needed. We have developed new hardware and improved numerical models to predict the eddy current probe signal due to cracks in metallic fast reactor parts by using volume integral equation method. The analytical expressions are derived for the quasi-static time-harmonic electromagnetic fields of a circular eddy current coil which interacts with conductive plate. Naturally, the method of moment is used to approximate the integral equation and obtain the discrete approximation of the field in the crack domain. A simple and accurate analytical method for dealing with the hyper-singularity element evaluation is also provided. An accurate controlled experiment is carried out on the ferromagnetic stainless steel plate with precision made notch to obtain reference impedance changes for comparison with the theoretical model predictions. Good agreement between predictions and experiment is obtained.

  15. Optimization of planar Hall resistance using biaxial currents in a NiO/NiFe bilayer: Enhancement of magnetic field sensitivity

    NASA Astrophysics Data System (ADS)

    Kim, D. Y.; Park, B. S.; Kim, C. G.

    2000-09-01

    We present the optimized planar Hall resistance (PHR) obtained by using biaxial currents in a NiO (30 nm)/NiFe (30 nm) bilayers. The measured PHR, Rxy, had a drift resistance due to the intrinsic and extrinsic characteristics caused by magnetization and sample geometry, respectively. The drift voltage due to drift resistance restricted the PHR ratio and could be compensated for by using the auxiliary current Ix for the sensing current Iy to enhance PHR ratio. A huge PHR ratio over 3000% (±1500%) with the linearity and small hysteresis for the magnetic field experimentally obtained using biaxial currents and could be explained by the anisotropic characteristic of the magnetoresistance, which is influenced by the exchange coupling field (Hex) induced by the antiferromagnetic NiO layer.

  16. Two-dimensional direct-current resistivity survey to supplement borehole data in ground-water models of the former Blaine Naval Ammunition Depot, Hastings, Nebraska, September 2003

    USGS Publications Warehouse

    Kress, Wade H.; Ball, Lyndsay B.; Teeple, Andrew; Turco, Michael J.

    2006-01-01

    The former Blaine Naval Ammunition Depot located immediately southeast of Hastings, Nebraska, was an ammunition facility during World War II and the Korean Conflict. Waste-management practices during operation and decommissioning of the former Depot resulted in soil and ground-water contamination. Ground-water models have been used by the U.S. Army Corps of Engineers to provide information on the fate and transport of contaminants on the former Depot site. During September 2003, the U.S. Geological Survey, in cooperation with the U.S. Army Corps of Engineers, Kansas City District, conducted a pilot study to collect two-dimensional direct-current resistivity data on the site along six profiles near existing monitoring wells. The inversion results of field data from five of the six two-dimensional direct-current resistivity profiles display distinct electrical stratigraphy consistent with three resistivity units (low resistivity, high resistivity, and low resistivity). These three resistivity units correlate with rock-stratigraphic or hydrogeologic units described prior to this study. To interpret the resistivity profiles, additional data extending through the lower confining unit into the underlying Niobrara Formation could be used with the existing data to construct forward models for data analysis and interpretation.

  17. Development and successful testing of MCP BSCCO-2212 components for a 10 MVA resistive superconducting fault current limiter

    NASA Astrophysics Data System (ADS)

    Bock, J.; Breuer, F.; Walter, H.; Noe, M.; Kreutz, R.; Kleimaier, M.; Weck, K.-H.; Elschner, S.

    2004-05-01

    The German government funded resistive superconducting fault current limiter project CURL 10 is based on bulk material and aims at the development of a three-phase prototype for the medium voltage level (10 kV, 10 MVA). The key element of the project is the development of suitable robust superconducting components. On the basis of the well known melt cast process (MCP) for BSCCO-2212, these are manufactured by cutting superconducting tubes to bifilar coils. At the operation temperature of 65 K a current density of 4000 A cm-2 was achieved. In order to protect the superconductor during limitation the component was equipped with an electrical shunt contacted on its entire length. Single-phase tests with nine of these components in series, corresponding to a protected load of 1.2 MVA, have been successfully accomplished and are described in detail. These tests include different types of short circuits as specified by the utilities within the project and included lightning surge loads up to 75 kV.

  18. Determining resistivity of a formation adjacent to a borehole having casing with an apparatus having all current conducting electrodes within the cased well

    DOEpatents

    Vail, III, William Banning

    2001-01-01

    Methods of operation of different types of multiple electrode apparatus vertically disposed in a cased well to measure information useful to determine the resistivity of adjacent geological formations from within the cased well are described. The multiple electrode apparatus has a plurality of spaced apart voltage measurement electrodes that electrically engage a portion of the interior of the cased well. During measurements of information useful to determine formation resistivity, current is conducted between a first current conducting electrode in electrical contact with the interior of the cased well to a second current conducting electrode that is also in electrical contact with the interior of the cased well. The first and second current conducting electrodes are separated by a distance sufficient so that at least a portion of the current conducted between the first and second current conducting electrodes is conducted through the geological formation of interest.

  19. Multi-scale model of resistive-type superconducting fault current limiters based on 2G HTS coated conductors

    NASA Astrophysics Data System (ADS)

    Bonnard, Charles-Henri; Sirois, Frédéric; Lacroix, Christian; Didier, Gaëtan

    2017-01-01

    In order to plan the integration of superconducting fault current limiters (SFCLs) in power systems, accurate models of SFCLs must be made available in commercial power system transient simulators. In this context, we developed such a model for the EMTP-RV software package, a power system transient simulator widely used by power utilities. The model can be used with any resistive-type SFCL (rSFCL) made of high temperature superconductor (HTS) tapes, which are discretized in ‘electro-thermal elements’. Those elements consist solely of electric circuit components, and are used to represent portions of tape of various sizes and dimensions (a ‘multi-scale’ approach). Both the electrical and thermal behaviors of the tape are modeled, including interfacial effects, nonlinear properties of materials and heat transfer to the surrounding environment. Such a multi-scale model can simulate accurately both the local quench dynamics of HTS tapes (microscopic scale) and the global impact of the rSFCL on the power system (macroscopic/system scale). In this paper, the model is used to compute phenomena such as propagation velocity of a hot spot and heat diffusion through the thickness of the tape. Results were verified by comparing EMTP-RV results with finite element simulations. In addition to the development of the multi-scale model itself, which is the major contribution of this paper, the use of the model allowed us to determine the conditions of validity of the commonly used ‘homogenization’ of the thermal properties across the tape thickness. Indeed, when the current flowing into the rSFCL is slightly above its critical current I c (and up to 2{I}{{c}}), very important errors in the power waveforms arise, leading to potentially wrong decisions of protection systems. Homogenized thermal models should thus be used with great care in practice.

  20. Reinforcer magnitude and rate dependency: evaluation of resistance-to-change mechanisms.

    PubMed

    Pinkston, Jonathan W; Ginsburg, Brett C; Lamb, Richard J

    2014-10-01

    Under many circumstances, reinforcer magnitude appears to modulate the rate-dependent effects of drugs such that when schedules arrange for relatively larger reinforcer magnitudes rate dependency is attenuated compared with behavior maintained by smaller magnitudes. The current literature on resistance to change suggests that increased reinforcer density strengthens operant behavior, and such strengthening effects appear to extend to the temporal control of behavior. As rate dependency may be understood as a loss of temporal control, the effects of reinforcer magnitude on rate dependency may be due to increased resistance to disruption of temporally controlled behavior. In the present experiments, pigeons earned different magnitudes of grain during signaled components of a multiple FI schedule. Three drugs, clonidine, haloperidol, and morphine, were examined. All three decreased overall rates of key pecking; however, only the effects of clonidine were attenuated as reinforcer magnitude increased. An analysis of within-interval performance found rate-dependent effects for clonidine and morphine; however, these effects were not modulated by reinforcer magnitude. In addition, we included prefeeding and extinction conditions, standard tests used to measure resistance to change. In general, rate-decreasing effects of prefeeding and extinction were attenuated by increasing reinforcer magnitudes. Rate-dependent analyses of prefeeding showed rate-dependency following those tests, but in no case were these effects modulated by reinforcer magnitude. The results suggest that a resistance-to-change interpretation of the effects of reinforcer magnitude on rate dependency is not viable.

  1. Evaluation of the current radiofrequency ablation systems using axiomatic design theory.

    PubMed

    Zhang, Bing; Moser, Michael A J; Luo, Yigang; Zhang, Edwin M; Zhang, Wenjun

    2014-04-01

    This article evaluates current radiofrequency ablation systems using axiomatic design theory. Due to its minimally invasive procedure, short-time hospital stay, low cost, and tumour metastasis treatment, the radiofrequency ablation technique has been playing an important role in tumour treatment in recent decades. Although the radiofrequency ablation technique has many advantages, some issues still need to be addressed. Among these issues, the two most important are as follows: (1) the size of tumours to be removed (has to be larger than 3 cm in diameter) and (2) cleanness of the removal. Many device solutions have been proposed to address the two issues. However, there is a lack of knowledge regarding the systematic evaluation of these solutions. This article evaluates these systems in terms of their solution principles (or simply called conceptual design in general product design theory) using a design theory called axiomatic design theory. In addition, with the axiomatic design theory, a better conceptual design in terms of its feasibility to cope with incomplete target tissue necrosis from the large size of tumours has been found. The detailed analysis and simulation of the new conceptual design are conducted using finite element approach. The results in this article are proved by the information of animal experiments and clinical practices obtained from the literature. This study thus contributes to the current knowledge to further developments in radiofrequency ablation systems and procedure guidelines for physicians to perform the radiofrequency ablation operation more effectively.

  2. [Evaluation of penicillin-binding protein genotypes in penicillin susceptible and resistant Streptococcus pneumoniae isolates].

    PubMed

    Aslan, Gönül; Tezcan, Seda; Delialioğlu, Nuran; Aydın, Fatma Esin; Kuyucu, Necdet; Emekdaş, Gürol

    2012-04-01

    Penicillin-binding proteins (PBPs) are the natural targets of beta-lactam antibiotics and mutations in pbp1a, pbp2b, and pbp2x genes, which encode PBPs, are responsible for resistance to beta-lactams in Streptococcus pneumoniae. In the present study, we intended to determine how often the common mutation patterns occurred within the pbp1a, pbp2b, and pbp2x PBP gene regions and evaluate the PBP genotype mutations which were associated with penicillin resistance in several penicillin-susceptible and - resistant S.pneumoniae isolates in Mersin, Turkey. A total of 62 S.pneumoniae strains isolated from different clinical specimens (32 nasopharyngeal swab, 16 sputum, 3 blood, 3 wound, 2 cerebrospinal fluids and one of each urine, abscess, bronchoalveolar lavage, conjunctival swab, tracheal aspirate, middle ear effusion) were included in the study. Penicillin susceptibilities of the isolates were searched by disc diffusion and E-test methods, and 23 of them were identified as susceptible, 31 were intermediate susceptible, and eight were resistant to penicillin. A rapid DNA extraction procedure was performed for the isolation of nucleic acids from the strains. Distribution of PBP gene mutations in pbp1a, pbp2b, and pbp2x gene regions related to penicillin resistance was determined by using a wild-type specific polymerase chain reaction (PCR) based technique. PBP gene alterations of those isolates were also evaluated in relation to penicillin susceptibility and resistance patterns. Twenty two (95.7%) of 23 penicillin-susceptible S.pneumoniae isolates exhibited no mutation in the three PBP genes (pbp1a, pbp2x, and pbp 2b), while 1 (4.3%) of these harbored mutations in all of the three PBP genes. The penicillin-intermediate susceptible S.pneumoniae isolates exhibited various combinations of mutations. One (3.2%) of 31 penicillin-intermediate susceptible isolates exhibited no mutation in the three PBP genes, while 22 (71%) of them yielded mutations in all of the three PBP

  3. Evaluation of the Comparative Corrosion Resistance Between AKOT Ti Alloy and Ti Gr 7 Alloy

    SciTech Connect

    Lian, T

    2005-08-01

    In its current design, the drip shields for the high-level nuclear waste containers for the Yucca Mountain repository will be mainly made using Ti Gr 7 (R52400). Ti Gr 7 is a highly corrosion resistant alloy, especially because it contains 0.15% palladium (Pd). The goal of this study was to determine whether an AKOT low-Pd (0.01%) titanium alloy would have a similar corrosion resistance than the more expensive Ti Gr 7 in environments that could be related to the performance of the drip shield. The focus of this testing program was on the susceptibility of the alloys to localized corrosion. Therefore, only artificially creviced specimens were used.

  4. Evaluation of a Photosynthesis-Based Canopy Resistance Formulation in the Noah Land-Surface Model

    NASA Astrophysics Data System (ADS)

    Kumar, Anil; Chen, Fei; Niyogi, Dev; Alfieri, Joseph G.; Ek, Michael; Mitchell, Kenneth

    2011-02-01

    Accurately representing complex land-surface processes balancing complexity and realism remains one challenge that the weather modelling community is facing nowadays. In this study, a photosynthesis-based Gas-exchange Evapotranspiration Model (GEM) is integrated into the Noah land-surface model replacing the traditional Jarvis scheme for estimating the canopy resistance and transpiration. Using 18-month simulations from the High Resolution Land Data Assimilation System (HRLDAS), the impact of the photosynthesis-based approach on the simulated canopy resistance, surface heat fluxes, soil moisture, and soil temperature over different vegetation types is evaluated using data from the Atmospheric Radiation Measurement (ARM) site, Oklahoma Mesonet, 2002 International H2O Project (IHOP_2002), and three Ameriflux sites. Incorporation of GEM into Noah improves the surface energy fluxes as well as the associated diurnal cycle of soil moisture and soil temperature during both wet and dry periods. An analysis of midday, average canopy resistance shows similar day-to-day trends in the model fields as seen in observed patterns. Bias and standard deviation analyses for soil temperature and surface fluxes show that GEM responds somewhat better than the Jarvis scheme, mainly because the Jarvis approach relies on a parametrised minimum canopy resistance and meteorological variables such as air temperature and incident radiation. The analyses suggest that adding a photosynthesis-based transpiration scheme such as GEM improves the ability of the land-data assimilation system to simulate evaporation and transpiration under a range of soil and vegetation conditions.

  5. Laboratory evaluation of phenotypic detection methods of methicillin-resistant Staphylococcus aureus.

    PubMed

    Kali, Arunava; Stephen, Selvaraj; Umadevi, Sivaraman

    2014-01-01

    Although conventional antibiotic susceptibility tests are most commonly performed for methicillin-resistant Staphylococcus aureus (MRSA), the results of these phenotypic tests are dependent on the standardization of the culture conditions. The aim of the study was to evaluate the conventional phenotypic screening tests in comparison to the mecA gene polymerase chain reaction (PCR). One hundred and two clinical isolates of MRSA identified by the oxacillin disk diffusion were subjected to PCR for the mecA gene and by the cefoxitin disk diffusion test and culture on oxacillin screen agar, mannitol salt agar, and methicillin-resistant Staphylococcus aureus Agar (MeReSA) selective medium, for MRSA. Although all 102 isolates were resistant in oxacillin and cefoxitin disk diffusion, 92 (90.1%) isolates were positive for the mecA gene. The sensitivities of the mannitol salt agar, MeReSA agar, and oxacillin screen agar were 89.13, 97.82, and 98.91%, respectively. The oxacillin screen agar may be recommended for confirming methicillin resistance in the disk diffusion test in resource-poor settings, where molecular methods are not available.

  6. Detection of DC currents and resistance measurements in longitudinal spin Seebeck effect experiments on Pt/YIG and Pt/NFO

    NASA Astrophysics Data System (ADS)

    Meier, Daniel; Kuschel, Timo; Meyer, Sibylle; Goennenwein, Sebastian T. B.; Shen, Liming; Gupta, Arunava; Schmalhorst, Jan-Michael; Reiss, Günter

    2016-05-01

    In this work we investigated thin films of the ferrimagnetic insulators Y 3Fe5O12 and NiFe2O4 capped with thin Pt layers in terms of the longitudinal spin Seebeck effect (LSSE). The electric response detected in the Pt layer under an out-of-plane temperature gradient can be interpreted as a pure spin current converted into a charge current via the inverse spin Hall effect. Typically, the transverse voltage is the quantity investigated in LSSE measurements (in the range of μV). Here, we present the directly detected DC current (in the range of nA) as an alternative quantity. Furthermore, we investigate the resistance of the Pt layer in the LSSE configuration. We found an influence of the test current on the resistance. The typical shape of the LSSE curve varies for increasing test currents.

  7. Intrawire resistance, AC loss and strain dependence of critical current in MgB2 wires with and without cold high-pressure densification

    NASA Astrophysics Data System (ADS)

    Zhou, C.; Gao, P.; Krooshoop, H. J. G.; Dhallé, M.; Sumption, M. D.; Rindfleisch, M.; Tomsic, M.; Kulich, M.; Senatore, C.; Nijhuis, A.

    2014-07-01

    The intrawire resistance and alternating current (AC) loss of two MgB2 wires with filaments surrounded by Nb barriers have been measured and analyzed. Relatively high values of filament-to-matrix contact resistivity are found in the MgB2 wires; the values are two or three orders higher than those commonly found in NbTi or Nb3Sn wires. Considering the high porosity of the MgB2 filaments, cold high-pressure densification has been applied on the two MgB2 wires to investigate its impact on intrawire resistance and AC loss. The intrawire resistance is measured with a direct four-probe voltage-current method at various temperatures. The AC loss is measured by vibrating sample magnetometer measurements at 4.2 K. In addition to the intrawire resistance measurements, the critical current of MgB2 wires before and after densification is measured with a U-shaped bending spring at 4.2 K as function of axial strain. The critical current in densified MgB2 wires is found to be higher than that in the same wire without densification; it is also less sensitive to the applied axial strain.

  8. [Current laboratory methods to evaluate the efficiency of immunization against dangerous and extremely dangerous infections].

    PubMed

    Bogacheva, N V; Darmov, I V; Elagin, G D; Kriuchkov, A V; Tikhvinskaia, O V

    2011-06-01

    By taking into account the leading role of specific cellular immunity in the development of protection against the majority of dangerous and extremely dangerous infections of bacterial, viral, and rickettsial nature, the study of the above immunity should be considered as most important on estimating the body's immunological rearrangement when vaccines against respective infections are administered. The battery of the test used to date for the analysis of specific cellular immunity is mainly restricted to skin tests that have disadvantages. This paper reviews the currently available laboratory methods for in vitro studies of a specific cellular immune response as a criterion for evaluating the efficiency of immunization.

  9. Dynamic Strength Evaluations for Self-Piercing Rivets and Resistance Spot Welds Joining Similar and Dissimilar Metals

    SciTech Connect

    Sun, Xin; Khaleel, Mohammad A.

    2007-10-01

    This paper summarizes the dynamic joint strength evaluation procedures and the measured dynamic strength data for thirteen joint populations of self-piercing rivets (SPR) and resistance spot welds (RSW) joining similar and dissimilar metals. A state-of-the-art review of the current practice for conducting dynamic tensile/compressive strength tests in different strain rate regimes is first presented, and the generic issues associated with dynamic strength test are addressed. Then, the joint strength testing procedures and fixture designs used in the current study are described, and the typical load versus displacement curves under different loading configurations are presented. Uniqueness of the current data compared with data in the open literature is discussed. The experimental results for all the joint populations indicate that joint strength increases with increasing loading rate. However, the strength increase from 4.47m/s (10mph) to 8.94m/s (20mph) is not as significant as the strength increase from static to 4.47m/s. It is also found that with increasing loading velocity, displacement to failure decreases for all the joint samples. Therefore, “brittleness” of the joint sample increases with impact velocity. Detailed static and dynamic strength data and the associated energy absorption levels for all the samples in the thirteen joint populations are also included.

  10. Prostaglandin E2 potentiates a TTX-resistant sodium current in rat capsaicin-sensitive vagal pulmonary sensory neurones.

    PubMed

    Kwong, Kevin; Lee, Lu-Yuan

    2005-04-15

    Capsaicin-sensitive vagal pulmonary neurones (pulmonary C neurones) play an important role in regulating airway function. During airway inflammation, the level of prostaglandin E(2) (PGE(2)) increases in the lungs and airways. PGE(2) has been shown to sensitize isolated pulmonary C neurones. The somatosensory correlate of the pulmonary C neurone, the small-diameter nociceptive neurone of the dorsal root ganglion, contains a high percentage of tetrodotoxin-resistant sodium currents (TTX-R I(Na)). Therefore, this study was carried out to determine whether these channel currents are involved in the PGE(2)-induced sensitization of pulmonary C neurones. We used the perforated patch-clamp technique to study the effects of PGE(2) on the TTX-R I(Na) in acutely cultured capsaicin-sensitive pulmonary neurones that were identified by retrograde labelling with a fluorescent tracer, DiI. We found that the pulmonary neurones sensitive to capsaicin had a higher percentage of TTX-R I(Na) than that of capsaicin-insensitive pulmonary neurones. PGE(2) exposure increased the evoked TTX-R I(Na) when experiments were performed at both room temperature and at 37 degrees C. Furthermore, stimulation of the adenylyl cyclase/protein kinase A pathway with either forskolin or Sp-5,6-DCl-cBiMPS potentiated the TTX-R I(Na) in a manner similar to that of PGE(2). We conclude that these modulatory effects of PGE(2) on TTX-R I(Na) play an important role in the sensitization of pulmonary C neurones.

  11. Evaluating the osseointegration of nanostructured titanium implants in animal models: Current experimental methods and perspectives (Review).

    PubMed

    Babuska, Vaclav; Moztarzadeh, Omid; Kubikova, Tereza; Moztarzadeh, Amin; Hrusak, Daniel; Tonar, Zbynek

    2016-09-15

    The aim of this paper is to review the experimental methods currently being used to evaluate the osseointegration of nanostructured titanium implants using animal models. The material modifications are linked to the biocompatibility of various types of oral implants, such as laser-treated, acid-etched, plasma-coated, and sand-blasted surface modifications. The types of implants are reviewed according to their implantation site (endoosseous, subperiosteal, and transosseous implants). The animal species and target bones used in experimental implantology are carefully compared in terms of the ratio of compact to spongy bone. The surgical technique in animal experiments is briefly described, and all phases of the histological evaluation of osseointegration are described in detail, including harvesting tissue samples, processing undemineralized ground sections, and qualitative and quantitative histological assessment of the bone-implant interface. The results of histological staining methods used in implantology are illustrated and compared. A standardized and reproducible technique for stereological quantification of bone-implant contact is proposed and demonstrated. In conclusion, histological evaluation of the experimental osseointegration of dental implants requires careful selection of the experimental animals, bones, and implantation sites. It is also advisable to use larger animal models and older animals with a slower growth rate rather than small or growing experimental animals. Bones with a similar ratio of compact to spongy bone, such as the human maxilla and mandible, are preferred. A number of practical recommendations for the experimental procedures, harvesting of samples, tissue processing, and quantitative histological evaluations are provided.

  12. Evaluation of Bag-Valve-Mask Ventilation in Manikin Studies: What Are the Current Limitations?

    PubMed Central

    Pugin, A.; Pili-Floury, S.; Pazart, L.; Capellier, G.

    2016-01-01

    Introduction. Manikin-based studies for evaluation of ventilation performance show high heterogeneity in the analysis and experimental methods used as we pointed out in previous studies. In this work, we aim to evaluate these potential limitations and propose a new analysis methodology to reliably assess ventilation performance. Methods. One hundred forty healthcare providers were selected to ventilate a manikin with two adult self-inflating bags in random order. Ventilation parameters were analysed using different published analysis methods compared to ours. Results. Using different methods impacts the evaluation of ventilation efficiency which ranges from 0% to 45.71%. Our new method proved relevant and showed that all professionals tend to cause hyperventilation and revealed a significant relationship between professional category, grip strength of the hand keeping the mask, and ventilation performance (p = 0.0049 and p = 0.0297, resp.). Conclusion. Using adequate analysis methods is crucial to avoid many biases. Extrapolations to humans still have to be taken with caution as many factors impact the evaluation of ventilation performance. Healthcare professionals tend to cause hyperventilation with current devices. We believe this problem could be prevented by implementing monitoring tools in order to give direct feedback to healthcare professionals regarding ventilation efficiency and ventilatory parameter values. PMID:27294119

  13. Current status of insecticide resistance in Helicoverpa armigera after 15 years of Bt cotton planting in China.

    PubMed

    Yang, Yihua; Li, Yapeng; Wu, Yidong

    2013-02-01

    Insecticide resistance was an important factor responsible for outbreaks of Helicoverpa armigera (Hübner) in China in the early 1990s. Bt cotton has been adopted in China since 1997, and has resulted in a reduction of insecticide use for H. armigera control. After 15 yr of Bt cotton planting, in 2011 we surveyed resistance to fenvalerate, phoxim, and emamectin benzoate in 16 field populations of H. armigera collected from major cotton production areas of China. Fourteen populations from northern China showed very strong resistance to fenvalerate (from 43- to 830-fold) and low levels of resistance to phoxim (3.0- to 8.9-fold) when compared with the susceptible SCD strain of H. armigera, whereas two populations from northwestern China showed low levels of resistance to fenvalerate (3.0- and 10-fold) and no resistance to phoxim (0.7- and 0.9-fold). Synergist bioassays demonstrated that oxidase-based detoxification was involved in fenvalerate resistance and esterase-based detoxification in phoxim resistance in the resistant field populations. In comparison with the resistance in field populations before Bt cotton adoption, we observed a maintenance of high levels of fenvalerate resistance, but a reversion of phoxim resistance from high levels to low levels in the field populations of H. armigera from northern China. All 16 field populations from both northern China and northwestern China were susceptible to emamectin benzoate (with about two-fold variations in LD50s among populations), but the SCD strain has an inherent tolerance of 11-fold compared with the most susceptible field population (Xiajin-1). Emamectin benzoate is not cross resistant to fenvalerate and may provide an alternative option for H. armigera control in China, if the efficacy of Bt cotton is compromised by Bt resistance in the field.

  14. In-beam evaluation of a medium-size Resistive-Plate WELL gaseous particle detector

    NASA Astrophysics Data System (ADS)

    Moleri, L.; Amaro, F. D.; Arazi, L.; Azevedo, C. D. R.; Breskin, A.; Coimbra, A. E. C.; Oliveri, E.; Pereira, F. A.; Shaked Renous, D.; Schaarschmidt, J.; dos Santos, J. M. F.; Veloso, J. F. C. A.; Bressler, S.

    2016-09-01

    In-beam evaluation of a fully-equipped medium-size 30 × 30 cm2 Resistive Plate WELL (RPWELL) detector is presented. It consists here of a single element gas-avalanche multiplier with Semitron ESD225 resistive plate, 1 cm2 readout pads and APV25/SRS electronics. Similarly to previous results with small detector prototypes, stable operation at high detection efficiency (> 98%) and low average pad multiplicity (~ 1.2) were recorded with 150 GeV muon and high-rate pion beams, in Ne/(5%CH4), Ar/(5%CH4) and Ar/(7%CO2). This is an important step towards the realization of robust detectors suitable for applications requiring large-area coverage; among them Digital Hadron Calorimetry.

  15. Evaluation of atomic oxygen resistant protective coatings for fiberglass-epoxy composites in LEO

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon K.; Paulsen, Phillip E.; Brady, Joyce A.

    1989-01-01

    Fiberglass-epoxy composite masts are the prime structural members for the Space Station Freedom solar array. At the altitude where Space Station Freedom will operate, atomic oxygen atoms are the most predominant species. Atomic oxygen is highly reactive and has been shown to oxidize organic and some metallic materials. Tests with random and directed atomic oxygen exposure have shown that the epoxy is removed from the composite exposing brittle glass fibers which could be easily removed from the surface where they could contaminate Space Station Freedom Systems. Protection or fiber containment systems; inorganic based paints, aluminum braid, and a metal coating; were evaluated for resistance to atomic oxygen, vacuum ultraviolet radiation, thermal cycling, and mechanical flexing. All appeared to protect well against atomic oxygen and provide fiber containment except for the single aluminum braid covering. UV radiation resistance was acceptable and in general, thermal cycling and flexure had little to no effect on the mass loss rate for most coatings.

  16. A ballistic evaluation of the impact resistance of spectacle lens materials.

    PubMed

    Oliver, A L; Chou, B R

    1993-10-01

    The impact resistance of chemically and thermally hardened glass lenses of 2.2- and 3.0-mm thicknesses was evaluated using a ballistic test. Each lens was edged and mounted into a spectacle frame, which was placed on a standard headform. A 6.5-mm steel ball was fired from an air gun at the center of the lens at increasing speeds until the lens broke. The multiple impact data were used to plot cumulative breakage curves. We found that heat-treated photochromic glass and heat-treated crown glass fail at similar missile speeds and that chemical treating considerably improves the impact resistance of crown glass but not of photochromic glass. The poorer performance of photochromic lenses indicates that they should not be prescribed when optimal impact protection is required. Plastic lenses show superior performance.

  17. Preliminary evaluation of apple germplasm from Kazakhstan for resistance to blue mold decay caused by Penicillium expansum after harvest

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Blue mold of apples, incited by Penicillium expansum, causes extensive loss on stored apples worldwide. Despite the severity of this problem, apple breeders do not evaluate their crosses for resistance to this disease, because there has been little resistance to blue mold in the gene pool of the ge...

  18. Application of Direct Current Potential Drop for the J-integral vs. Crack Growth Resistance Curve Characterization

    SciTech Connect

    Chen, Xiang; Nanstad, Randy K; Sokolov, Mikhail A

    2014-01-01

    The direct current potential drop (DCPD) technique has been applied to derive the J-integral vs. crack growth resistance curve (J-R curve) for fracture toughness characterization of structural materials. The test matrix covered three materials including type 316LN stainless steels, Ni-based alloy 617, and one ferritic-martensitic steel, three specimen configurations including standard compact, single edge bending, and disk-shaped compact specimens, and temperatures ranging from 20 C to 650 C. When compared with baseline J-R curves derived from the ASTM normalization method, the original J-R curves from the DCPD technique yielded much smaller Jq values due to the influence of crack blunting, plastic deformation, etc. on potential drop. To counter these effects, a new procedure for adjusting DCPD J-R curves was proposed. After applying the new adjustment procedure, the average difference in Jq between the DCPD technique and the normalization method was only 5.2% and the difference in tearing modulus was 7.4%. The promising result demonstrates the applicability of the DCPD technique for the J-R curve characterization especially in extreme environments, such as elevated temperatures, where the conventional elastic unloading compliance method faces considerable challenges.

  19. Carrier sheet density constrained anomalous current saturation of graphene field effect transistors: kinks and negative differential resistances.

    PubMed

    Wang, Xiaomu; Xu, Haitao; Min, Jie; Peng, Lian-Mao; Xu, Jian-Bin

    2013-04-07

    There has recently been a great deal of interest and excitement in applying graphene field effect transistors (GFETs) in digital and radio frequency (RF) circuits and systems. Peculiar output characteristics such as kinks and negative differential resistance (NDR) in a strong field are the unique transport properties of GFETs. Here we demonstrate that these unusual features are attributed to a carrier sheet density constrained transport framework. Simulation results based on a simple analytic model which includes the linear DOS structure are in very good agreement with experimental data. The kernel mechanism of NDR is ascribed to the fact that the total current increase of a channel with a high average carrier density is constrained by its minimum sheet density. Utilizing in situ Kelvin probe force microscopy (KPFM), the principle which naturally distinguishes NDR from kinks is further verified by studying the spatially resolved surface potential distribution along the channel. The influence and potential application of GFETs' unique output characteristics in the digital and RF fields are also proposed.

  20. Evaluation of the potential antimicrobial resistance transfer from a multi-drug resistant Escherichia coli to Salmonella in dairy calves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Previous research conducted by our laboratory investigated the incidence of multi-drug resistant (MDR) Salmonella in dairy cattle and reported that individual cattle, and most often calves, shed multiple Salmonella serotypes that vary in the degree of antibiotic resistance. More recently, we invest...

  1. Original non-stationary eddy current imaging process for the evaluation of defects in metallic structures

    NASA Astrophysics Data System (ADS)

    Placko, Dominique; Bore, Thierry; Rivollet, Alain; Joubert, Pierre-Yves

    2015-10-01

    This paper deals with the problem of imaging defects in metallic structures through eddy current (EC) inspections, and proposes an original process for a possible tomographical crack evaluation. This process is based on a semi analytical modeling, called "distributed point source method" (DPSM) which is used to describe and equate the interactions between the implemented EC probes and the structure under test. Several steps will be successively described, illustrating the feasibility of this new imaging process dedicated to the quantitative evaluation of defects. The basic principles of this imaging process firstly consist in creating a 3D grid by meshing the volume potentially inspected by the sensor. As a result, a given number of elemental volumes (called voxels) are obtained. Secondly, the DPSM modeling is used to compute an image for all occurrences in which only one of the voxels has a different conductivity among all the other ones. The assumption consists to consider that a real defect may be truly represented by a superimposition of elemental voxels: the resulting accuracy will naturally depend on the density of space sampling. On other hand, the excitation device of the EC imager has the capability to be oriented in several directions, and driven by an excitation current at variable frequency. So, the simulation will be performed for several frequencies and directions of the eddy currents induced in the structure, which increases the signal entropy. All these results are merged in a so-called "observation matrix" containing all the probe/structure interaction configurations. This matrix is then used in an inversion scheme in order to perform the evaluation of the defect location and geometry. The modeled EC data provided by the DPSM are compared to the experimental images provided by an eddy current imager (ECI), implemented on aluminum plates containing some buried defects. In order to validate the proposed inversion process, we feed it with computed

  2. Evaluation of two molecular assays for rapid detection of mycobacterium tuberculosis resistance to fluoroquinolones in high-tuberculosis and -multidrug-resistance Settings.

    PubMed

    Kontsevaya, I; Mironova, S; Nikolayevskyy, V; Balabanova, Y; Mitchell, S; Drobniewski, F

    2011-08-01

    The Russian Federation is a high-tuberculosis (TB)-burden country with high rates of drug resistance, including multidrug and extensive drug resistance to TB (M/XDRTB). Rapid diagnosis of resistance to fluoroquinolones (FQs) using molecular assays is essential for the implementation of appropriate drug regimens and prevention of the transmission of XDR strains. A total of 51 individual MDRTB strains were tested by pyrosequencing of the quinolone resistance determining region of the gyrA gene and the GenoType MTBDRsl assay (Hain Lifescience, GmbH, Nehren, Germany), and the results were evaluated against those obtained by phenotypic drug susceptibility testing (DST). Mutations were detected in 25 (78.1%) FQ-resistant strains, with the majority of mutations (n = 19 [73.0%]) found in codon 94 of the gyrA gene; the novel mutation 1457 C→Τ was found in the gyrB gene. Three mixed allelic variants were detected, which is a well-known phenomenon in areas with high TB and drug-resistant TB rates. The sensitivity and specificity of pyrosequencing (86.2 and 100%, respectively) and MTBDRsl (86.2 and 100%, respectively) were high; however, the results for 5.9% of the analyzed strains were unreadable when MTBDRsl was used. The MTBDRsl and pyrosequencing assays offer a rapid and accurate means for diagnosing resistance to FQs in high-TB-burden areas.

  3. [Frost-resistance of subtropical evergreen woody plants: an evaluation based on plant functional traits].

    PubMed

    Xu, Yi-Lu; Yang, Xiao-Dong; Xu, Yue; Xie, Yi-Ming; Wang, Liang-Yan; Yan, En-Rong

    2012-12-01

    Evaluating the frost-resistance of evergreen woody plants is of significance in guiding the species selection in forest management in subtropical region. In this paper, an investigation was made on the functional traits (including specific leaf area, stem wood density, leaf area, leaf dry matter content, leaf relative electrical conductance, and twig wood density) of 64 common evergreen broad-leaved and coniferous woody plant species in the Ningbo region of Zhejiang Province, East China, after a severe snowstorm in early 2008, aimed to select the evergreen woody plants with high ability of freeze-tolerance, and to establish a related evaluation system. By using a hierarchy analysis approach, the weight values of the functional traits of each species were determined, and an index system for evaluating the plants tolerance ability against freeze and mechanical damage was established. Based on this system, 23 evergreen plant species with high tolerance ability against freeze and mechanical damage, such as Cyclobalanopsis gilva, Cyclobalanopsis nubium, Neolitsea aurata, and Vacciniuim mandarinorum, were selected. In the meantime, on the basis of the ordering with each of the functional traits, the ordering of the tolerance ability of the 64 plant species against freeze and mechanical damage was made, and a list for the frost-resistance ability of the subtropical evergreen woody plant species in Ningbo region was constituted.

  4. Methodology Development and Applications of Proliferation Resistance and Physical Protection Evaluation.

    SciTech Connect

    Bari, R.A.; Peterson, P.F., Therios, I.U., Whitlock, J.J.

    2010-04-11

    We present an overview of the program on the evaluation methodology for proliferation resistance and physical protection (PR&PP) of advanced nuclear energy systems (NESs) sponsored by the Generation IV International Forum (GIF). For a proposed NES design, the methodology defines a set of challenges, analyzes system response to these challenges, and assesses outcomes. The challenges to the NES are the threats posed by potential actors (proliferant States or sub-national adversaries). The characteristics of Generation IV systems, both technical and institutional, are used to evaluate the response of the system and to determine its resistance against proliferation threats and robustness against sabotage and terrorism threats. The outcomes of the system response are expressed in terms of a set of measures, which are the high-level PR&PP characteristics of the NES. The methodology is organized to allow evaluations to be performed at the earliest stages of system design and to become more detailed and more representative as the design progresses. It can thus be used to enable a program in safeguards by design or to enhance the conceptual design process of an NES with regard to intrinsic features for PR&PP.

  5. Evaluating Cloud and Precipitation Processes in Numerical Models using Current and Potential Future Satellite Missions

    NASA Astrophysics Data System (ADS)

    van den Heever, S. C.; Tao, W. K.; Skofronick Jackson, G.; Tanelli, S.; L'Ecuyer, T. S.; Petersen, W. A.; Kummerow, C. D.

    2015-12-01

    Cloud, aerosol and precipitation processes play a fundamental role in the water and energy cycle. It is critical to accurately represent these microphysical processes in numerical models if we are to better predict cloud and precipitation properties on weather through climate timescales. Much has been learned about cloud properties and precipitation characteristics from NASA satellite missions such as TRMM, CloudSat, and more recently GPM. Furthermore, data from these missions have been successfully utilized in evaluating the microphysical schemes in cloud-resolving models (CRMs) and global models. However, there are still many uncertainties associated with these microphysics schemes. These uncertainties can be attributed, at least in part, to the fact that microphysical processes cannot be directly observed or measured, but instead have to be inferred from those cloud properties that can be measured. Evaluation of microphysical parameterizations are becoming increasingly important as enhanced computational capabilities are facilitating the use of more sophisticated schemes in CRMs, and as future global models are being run on what has traditionally been regarded as cloud-resolving scales using CRM microphysical schemes. In this talk we will demonstrate how TRMM, CloudSat and GPM data have been used to evaluate different aspects of current CRM microphysical schemes, providing examples of where these approaches have been successful. We will also highlight CRM microphysical processes that have not been well evaluated and suggest approaches for addressing such issues. Finally, we will introduce a potential NASA satellite mission, the Cloud and Precipitation Processes Mission (CAPPM), which would facilitate the development and evaluation of different microphysical-dynamical feedbacks in numerical models.

  6. The genetics of resistance to powdery mildew in cultivated oats (Avena sativa L.): current status of major genes.

    PubMed

    Hsam, Sai L K; Mohler, Volker; Zeller, Friedrich J

    2014-05-01

    The genetics of resistance to powdery mildew caused by Blumeria graminis f. sp. avenae of four cultivated oats was studied using monosomic analysis. Cultivar 'Bruno' carries a gene (Pm6) that shows a recessive mode of inheritance and is located on chromosome 10D. Cultivar 'Jumbo' possesses a dominant resistance gene (Pm1) on chromosome 1C. In cultivar 'Rollo', in addition to the gene Pm3 on chromosome 17A, a second dominant resistance gene (Pm8) was identified and assigned to chromosome 4C. In breeding line APR 122, resistance was conditioned by a dominant resistance gene (Pm7) that was allocated to chromosome 13A. Genetic maps established for resistance genes Pm1, Pm6 and Pm7 employing amplified fragment length polymorphism (AFLP) markers indicated that these genes are independent of each other, supporting the results from monosomic analysis.

  7. Two dimensional joint inversion of direct current resistivity, radio-magnetotelluric and seismic refraction data: An application from Bafra Plain, Turkey

    NASA Astrophysics Data System (ADS)

    Demirci, İsmail; Candansayar, Mehmet Emin; Vafidis, Antonis; Soupios, Pantelis

    2017-04-01

    Direct current resistivity, radio-magnetotelluric and seismic refraction methods are widely used in the identification of near surface structures with collected data generally being interpreted separately. In recent decades, the use of joint inversion algorithms in geosciences has become widespread to identify near surface structures. However, there is no developed joint inversion algorithm using direct current resistivity, radio-magnetotelluric and seismic refraction methods. In this study, we developed a new two-dimensional joint inversion algorithm for direct current resistivity, radio-magnetotelluric and seismic refraction data based on a cross gradient approach. In addition, we proposed a new data weighting matrix to stabilize the convergence behavior of the joint inversion algorithms. We used synthetic data to show the advantage of the algorithm. The developed joint inversion algorithm found resistivity and velocity models that are better than the individual inversion of each data set. We also tested an algorithm with the field data collected in the Bafra Plain (Samsun, Turkey) to investigate saltwater intrusion. In comparing the field data inversion results with the sounding log, it can be seen that the developed joint inversion algorithm with the proposed data weighting matrix recovered the resistivity and velocity model better than the individual inversion and classical joint inversion of each data set. Our results showed that a more unique hydrogeological scenario might be obtained, especially in highly conductive media, with the joint usage of these methods.

  8. Coagulase-positive Staphylococcus isolated from wildlife: Identification, molecular characterization and evaluation of resistance profiles with focus on a methicillin-resistant strain.

    PubMed

    Nowakiewicz, Aneta; Ziółkowska, Grażyna; Zięba, Przemysław; Gnat, Sebastian; Wojtanowicz-Markiewicz, Katarzyna; Trościańczyk, Aleksandra

    2016-02-01

    The aim of the study was molecular analysis of coagulase-positive isolates of Staphylococcus bacteria obtained from wild animals and evaluation of their resistance to antimicrobial agents. A total of 76 rectal swabs were taken from wild animals. The species of the Staphylococcus isolates was determined by MALDI TOF MS, susceptibility to antimicrobials was evaluated by phenotypic and molecular methods, epidemiological analysis (ADSRRS-fingerprinting) was also carried out. MRSA isolate was typed by MLST and spa-typing. The animals tested, were carriers (n=38) of coagulase-positive Staphylococcus (S. aureus, S. pseudintermedius and S. delphini B). Analyzed isolates were resistant to 1 or 2 antimicrobials, which was confirmed by the presence of genes (blaZ, ermA, ermB, msrA, tetK and tetM). A multi-drug resistant and methicillin-resistant isolate of S. aureus was obtained as well (MRSA, ST8, t1635, PVL-positive and ACME-negative). The ADSRRS-fingerprinting method enabled interspecific and intraspecific differentiation of coagulase-positive Staphylococcus isolates, revealing a certain degree of correlation between the species of the isolate, and the degree of similarity between the isolates. The presence of resistance genes in 13% (5/38) of the isolates obtained from wild animals, including one methicillin-resistant isolate, is relatively small in comparison to the degree of colonization by resistant strains in humans, livestock or pets. Nevertheless, due to the possibility of contact between wild animals, domestic animals and humans, transmission of resistant strains is possible, as suggested by our isolation of a MRSA strain typed as ST8 and specific spa type t1635, which had previously been isolated exclusively from humans.

  9. School Evaluation: Current Practices in OECD Countries and a Literature Review. OECD Education Working Papers, No. 42

    ERIC Educational Resources Information Center

    Faubert, Violaine

    2009-01-01

    This paper examines the current academic and policy literatures concerning school evaluation in primary and secondary education within the OECD countries. First, it provides a typology of the existing systems of school evaluation across the OECD. It encompasses the diverse criteria and instruments commonly used to carry out schools evaluation, as…

  10. Docetaxel-Resistance in Prostate Cancer: Evaluating Associated Phenotypic Changes and Potential for Resistance Transfer via Exosomes

    PubMed Central

    Corcoran, Claire; Rani, Sweta; O’Brien, Keith; O’Neill, Amanda; Prencipe, Maria; Sheikh, Rizwan; Webb, Glenn; McDermott, Ray; Watson, William; Crown, John; O’Driscoll, Lorraine

    2012-01-01

    Background Hormone-refractory prostate cancer remains hindered by inevitable progression of resistance to first-line treatment with docetaxel. Recent studies suggest that phenotypic changes associated with cancer may be transferred from cell-to-cell via microvesicles/exosomes. Here we aimed to investigate phenotypic changes associated with docetaxel-resistance in order to help determine the complexity of this problem and to assess the relevance of secreted exosomes in prostate cancer. Methodology/Principal Findings Docetaxel-resistant variants of DU145 and 22Rv1 were established and characterised in terms of cross-resistance, morphology, proliferation, motility, invasion, anoikis, colony formation, exosomes secretion their and functional relevance. Preliminary analysis of exosomes from relevant serum specimens was also performed. Acquired docetaxel-resistance conferred cross-resistance to doxorubicin and induced alterations in motility, invasion, proliferation and anchorage-independent growth. Exosomes expelled from DU145 and 22Rv1 docetaxel-resistant variants (DU145RD and 22Rv1RD) conferred docetaxel-resistance to DU145, 22Rv1 and LNCap cells, which may be partly due to exosomal MDR-1/P-gp transfer. Exosomes from prostate cancer patients’ sera induced increased cell proliferation and invasion, compared to exosomes from age-matched controls. Furthermore, exosomes from sera of patients undergoing a course of docetaxel treatment compared to matched exosomes from the same patients prior to commencing docetaxel treatment, when applied to both DU145 and 22Rv1 cells, showed a correlation between cellular response to docetaxel and patients’ response to treatment with docetaxel. Conclusions/Significance Our studies indicate the complex and multifaceted nature of docetaxel-resistance in prostate cancer. Furthermore, our in vitro observations and preliminary clinical studies indicate that exosomes may play an important role in prostate cancer, in cell-cell communication

  11. ASSESS (Analytic System and Software for Evaluating Safeguards and Security) update: Current status and future developments

    SciTech Connect

    Al-Ayat, R.A. ); Cousins, T.D. ); Hoover, E.R. )

    1990-07-15

    The Analytic System and Software for Evaluating Safeguards and Security (ASSESS) has been released for use by DOE field offices and their contractors. In October, 1989, we offered a prototype workshop to selected representatives of the DOE community. Based on the prototype results, we held the first training workshop at the Central Training Academy in January, 1990. Four additional workshops are scheduled for FY 1990. ASSESS is a state-of-the-art analytical tool for management to conduct integrated evaluation of safeguards systems at facilities handling facilities. Currently, ASSESS focuses on the threat of theft/diversion of special nuclear material by insiders, outsiders, and a special form of insider/outsider collusion. ASSESS also includes a neutralization module. Development of the tool is continuing. Plans are underway to expand the capabilities of ASSESS to evaluate against violent insiders, to validate the databases, to expand the neutralization module, and to assist in demonstrating compliance with DOE Material Control and Accountability (MC A) Order 5633.3. These new capabilities include the ability to: compute a weighted average for performance capability against a spectrum of insider adversaries; conduct defense-in-depth analyses; and analyze against protracted theft scenarios. As they become available, these capabilities will be incorporated in our training program. ASSESS is being developed jointly by Lawrence Livermore and Sandia National Laboratories under the sponsorship of the Department of Energy (DOE) Office of Safeguards and Security.

  12. Evaluation of the impact of current antismoking advice in the UK on women with planned pregnancies.

    PubMed

    Acharya, G; Jauniaux, E; Sathia, Leena; Griffin, M; Morgan, H

    2002-09-01

    Smoking during pregnancy (active or passive) is associated with increased health risks to the unborn child. Current policy on antismoking advice for pregnant women in the United Kingdom is based essentially on written information by means of leaflets given to them at the first antenatal visit. We evaluated the impact of this policy on the smoking habits of pregnant women. A sample of 180 women with planned pregnancies attending antenatal clinics at two teaching hospitals in North London was recruited over a 6-month period. All women were provided with the current antismoking counselling at their first visit at the end of the first trimester and asked to fill in a questionnaire around mid-gestation. The study population included 117 (65%) women who did not currently smoke (non-smokers) and 63 (35%) who were active smokers at the beginning of their pregnancy. Thirty-nine non-smokers were found to be passive smokers. Three women took up smoking during pregnancy. Among the smokers, 53 (84.1%) women made no change in their smoking behaviour during pregnancy, seven (11.1%) reduced their cigarette consumption and only three (4.8%) gave up smoking during the first half of pregnancy. None of the partners changed their smoking habits. All women were aware that smoking in pregnancy could be deleterious to their health and that of their fetus. Despite awareness of dangers of smoking, the prevalence of smoking among pregnant women remains very high after the first antenatal visit and the current antismoking policy based essentially on leaflets is not effective. Health-care professionals should spend more time to inform women adequately about the dangers of smoking and help them to quit before pregnancy.

  13. Methodology of evaluating the influence of the resistance of contact regions in the measurements of sheet resistance on stripes of ultrathin high-resistance materials.

    PubMed

    Náhlík, Josef; Kašpárková, Irena; Fitl, Přemysl

    2012-07-01

    The paper reviews the problems of measurement of sheet resistance of ultrathin high-resistance layers of organic semiconductors and the essential underlying problems. Particular attention is paid to potential influence of the resistance of contact regions on the results of direct measurement of sheet resistance of stripe-shaped layers. In this connection, we present a methodology of double length stripe resistance measurement (DLSRM), used above all to minimise the influence of contact regions on the measurement results. We deduce theoretical as well as practical possibilities of DLSRM in the diagnostics and quantitative characterisation of unsuitable or even faulty contacts on high-resistance layers. The application efficiency of the DLSRM method is documented by the results of sheet resistance measurement on zinc phthalocyanine with cathode sputtered planar contacts of noble metals (gold, platinum, or palladium). As expected, gold is the best contact material, but even in its application one cannot neglect the influence of contact regions. The presented method is universal and generally applicable to all materials where sheet resistance is the relevant parameter, and its assessment is based on measurements of the layer resistance in stripe arrangement.

  14. Evaluation of collapse resistance of RC frame structures for Chinese schools in seismic design categories B and C

    NASA Astrophysics Data System (ADS)

    Tang, Baoxin; Lu, Xinzheng; Ye, Lieping; Shi, Wei

    2011-09-01

    According to the Code for Seismic Design of Buildings (GB50011-2001), ten typical reinforced concrete (RC) frame structures, used as school classroom buildings, are designed with different seismic fortification intensities (SFIs) (SFI=6 to 8.5) and different seismic design categories (SDCs) (SDC=B and C). The collapse resistance of the frames with SDC=B and C in terms of collapse fragility curves are quantitatively evaluated and compared via incremental dynamic analysis (IDA). The results show that the collapse resistance of structures should be evaluated based on both the absolute seismic resistance and the corresponding design seismic intensity. For the frames with SFI from 6 to 7.5, because they have relatively low absolute seismic resistance, their collapse resistance is insufficient even when their corresponding SDCs are upgraded from B to C. Thus, further measures are needed to enhance these structures, and some suggestions are proposed.

  15. Elastic and Electrical Properties Evaluation of Low Resistivity Pays in Malay Basin Clastics Reservoirs

    NASA Astrophysics Data System (ADS)

    Almanna Lubis, Luluan; Ghosh, Deva P.; Hermana, Maman

    2016-07-01

    The elastic and electrical properties of low resistivity pays clastics reservoirs in Malay Basin are strongly dependent on the complex nature of the clay content, either dispersed or laminated/layered. Estimating the hydrocarbon pore volume from conventional electrical log, i.e. resistivity log, is quite a challenge. The low elastic impedance contrast also found as one of the challenge thus create a problem to map the distribution of the low resistivity reservoirs. In this paper, we evaluate the electrical properties and elastic rock properties to discriminate the pay from the adjacent cap rock or shale. Forward modeling of well log responses including electrical properties are applied to analyze the nature of the possible pays on laminated reservoir rocks. In the implementation of rock properties analysis, several conventional elastic properties are comparatively analyzed for the sensitivity and feasibility analysis on each elastic parameters. Finally, we discussed the advantages of each elastic parameters in detail. In addition, cross-plots of elastic and electrical properties attributes help us in the clear separation of anomalous zone and lithologic properties of sand and shale facies over conventional elastic parameter crossplots attributes. The possible relationship on electrical and elastic properties are discussed for further studies.

  16. Design and preliminary evaluation of an exoskeleton for upper limb resistance training

    NASA Astrophysics Data System (ADS)

    Wu, Tzong-Ming; Chen, Dar-Zen

    2012-06-01

    Resistance training is a popular form of exercise recommended by national health organizations, such as the American College of Sports Medicine (ACSM) and the American Heart Association (AHA). This form of training is available for most populations. A compact design of upper limb exoskeleton mechanism for homebased resistance training using a spring-loaded upper limb exoskeleton with a three degree-of-freedom shoulder joint and a one degree-of-freedom elbow joint allows a patient or a healthy individual to move the upper limb with multiple joints in different planes. It can continuously increase the resistance by adjusting the spring length to train additional muscle groups and reduce the number of potential injuries to upper limb joints caused by the mass moment of inertia of the training equipment. The aim of this research is to perform a preliminary evaluation of the designed function by adopting an appropriate motion analysis system and experimental design to verify our prototype of the exoskeleton and determine the optimal configuration of the spring-loaded upper limb exoskeleton.

  17. In Vitro Embryo Explant Cultures of Peanut to Evaluate Resistance to Ditylenchus destructor

    PubMed Central

    De Waele, D.; van der Walt, P. C. W.; Wilken, Ria; Basson, Selmaré; Jordaan, Elizabeth M.

    1990-01-01

    Population densities of D. destructor on embryo explants of 22 peanut genotypes grown in vitro were compared with those in roots and seeds of the same genotypes grown in the greenhouse. During the first 8 weeks after inoculation, the optimum incubation period was 6 weeks for maximum reproduction of Ditylenchus destructor on embryo explants of peanut (Arachis hypogaea L. cv. Sellie) inoculated with 250 nematodes at 25 C. Nematode numbers increased 17-fold. Deletion of MnSO₄ H₂O and a higher KH₂PO₄ concentration in the medium resulted in higher nematode reproduction. Resistance or susceptibility to D. destructor was observed in seeds of several genotypes but was not matched by differences in host suitability in roots. The results indicate that the factor for resistance or susceptibility to D. destructor is synthesized in the seeds of peanut but is not translocated to the roots. Use of embryo explant cultures of peanut as a rapid method to evaluate resistance to D. destructor did not work under the conditions described. PMID:19287727

  18. Evaluation of the local temperature of conductive filaments in resistive switching materials.

    PubMed

    Yalon, E; Cohen, S; Gavrilov, A; Ritter, D

    2012-11-23

    The resistive switching effect in metal oxides and other dielectric materials is among the leading future non-volatile memory technologies. Resistive switching is widely ascribed to the formation and rupture of conductive filaments in the oxide, which are generated by temperature-enhanced nano-scale ion migration or other thermal effects. In spite of the central role of the local filament temperature on the switching effect, as well as on the conduction and reliability physics, no measurement methods of the filament temperature are yet available. In this work, we report on a method for evaluating the conducting filament temperature, using a metal-insulator-semiconductor bipolar transistor structure. The filament temperature is obtained by analyzing the thermal excitation rate of electrons from the filament Fermi level into the conduction band of a p-type semiconductor electrode. Measurements were carried out to obtain the conductive filament temperature in hafnia at varying ambient temperatures in the range of 3-300 K. Significant Joule heating of the filament was observed across the entire measured ambient temperature range. The extracted temperatures provide physical insight into the resistive switching effect.

  19. Military Curricula for Vocational & Technical Education. Basic Electricity and Electronics Individualized Learning System. CANTRAC A-100-0010. Module Five: Relationships of Current, Voltage, and Resistance. Study Booklet.

    ERIC Educational Resources Information Center

    Chief of Naval Education and Training Support, Pensacola, FL.

    This individualized learning module on the relationships of current, voltage, and resistance is one in a series of modules for a course in basic electricity and electronics. The course is one of a number of military-developed curriculum packages selected for adaptaticn to vocational instructional and curriculum development in a civilian setting.…

  20. [Evaluation of a hospital outbreak related to carbapenem-resistant Pseudomonas aeruginosa].

    PubMed

    Cekin, Yeşim; Karagöz, Alper; Kızılateş, Filiz; Cekin, Ayhan Hilmi; Oztoprak Çuvalcı, Nefise; Bülbüller, Nurullah; Durmaz, Rıza

    2013-10-01

    Pseudomonas aeruginosa is an important nosocomial pathogen that causes opportunistic infections and hospital outbreaks. During October 2012, carbapenem-resistant P.aeruginosa strains with similar antibiotic resistance patterns, were isolated from specimens sent from the intensive care and plastic surgery units in our hospital. Thus a hospital outbreak was suspected. The microbiology laboratory database was retrospectively searched and all strains of P.aeruginosa isolated during the four month period, starting with the initial carbapenem-resistant strain in August 2012, was evaluated as a hospital outbreak. The aim of this study was to define the outbreak by investigating the clonal relationship between the strains, to detect the potential environmental sources and to evaluate the period of the outbreak, risk factors and the efficiency of infection control measures. The study was conducted between August-November 2012. Twenty patients with carbapenem-resistant P.aeruginosa (CRPA) positive cultures were included in the study. The control group consisted of 22 patients with carbapenem-susceptible P.aeruginosa (CSPA) positive cultures. The clonal relationship between 26 CRPA strains was studied by pulsed-field gel electrophoresis (PFGE). The PFGE results indicated that CRPA strains in our hospital were not related to a single clone, however, there were four major clones composed of four to eight strains. Logistic regression analysis indicated that the risk increased 15.7 fold (95% CI: 1.19-207.76) by the use of carbapenem, 76.8 fold (95% CI: 2.03-2901.30) by surgical procedures and 0.787 fold (95% CI: 0.63-0.97) by the duration of hospital stay. Surveillance cultures from health-care personel and the environment performed in course of the outbreak, yielded no growth of a strain with the similar antibiotic resistance pattern. The spread of CRPA has been controlled by the use of effective precautionary measures, regressing the isolate number to 0-1 strain/month. Since

  1. Anthelmintic resistance in gastrointestinal nematodes in goats and evaluation of FAMACHA diagnostic marker in Uganda.

    PubMed

    Nabukenya, Immaculate; Rubaire-Akiiki, Chris; Olila, Deogracious; Muhangi, Denis; Höglund, Johan

    2014-10-15

    Gastrointestinal nematodes (GIN) are a challenge to goat production globally causing reduced growth, morbidity and mortality. We report here results of the first nation-wide anthelmintic resistance (AR) study and validation of assessment of clinical anaemia with FAMACHA eye scores in goats in Uganda. From August to December 2012 the efficacy of albendazole (7.5mg/kg), levamisole (10.5mg/kg) and ivermectin (0.3mg/kg) against strongyle nematodes was tested on 33 goat farms in Soroti, Gulu, Mpigi, Mbarara and Ssembabule districts of Uganda. Altogether 497 goats were subjected to a total of 45 different faecal egg count reduction tests (FECRT), each involving 5-20 goats. On one farm all substances were tested. Faecal and blood samples were collected and FAMACHA eye scores evaluated on the day of treatment and 15 days later. A questionnaire survey was conducted on frequency, type and dose of anthelmintics used, farm size and grazing management system. Examination of infective third stage larvae (L3) from pooled faecal cultures demonstrated Haemonchus to be the predominant genus (>75%). Resistance to at least one anthelmintic group was detected on 61% of the 33 farms and in 49% of the 45 test groups. Prevalence of resistance to ivermectin, levamisole and albendazole was respectively 58%, 52% and 38%. Correlation between pre-treatment packed cell volume determinations and FAMACHA scores (r(498) = -0.89) was significant. Paddock grazing system (Odds ratio 4.9, 95% CI 1.4-17.3) and large farm size of >40 goats (odds ratio 4.4, 95% CI 1.2-16.1) were significant predictors of AR. In all districts, resistance to all three anthelmintics was higher on large-scale goat farms practising mostly paddock grazing. Interestingly, resistance to albendazole, the most commonly used anthelmintic in Uganda, was lower than that to ivermectin and levamisole. We recommend adaptation of FAMACHA to goats to help restrict anthelmintic treatment to heavily infected individuals. This will limit

  2. Evaluation of current methods used to analyze the expression profiles of ABC transporters yields an improved drug-discovery database

    PubMed Central

    Orina, Josiah N.; Calcagno, Anna Maria; Wu, Chung-Pu; Varma, Sudhir; Shih, Joanna; Lin, Min; Eichler, Gabriel; Weinstein, John N.; Pommier, Yves; Ambudkar, Suresh V.; Gottesman, Michael M.; Gillet, Jean-Pierre

    2009-01-01

    The development of multidrug resistance (MDR) to chemotherapy remains a major challenge in the treatment of cancer. Resistance exists against every effective anti-cancer drug and can develop by multiple mechanisms. These mechanisms can act individually or synergistically, leading to multidrug resistance (MDR), in which the cell becomes resistant to a variety of structurally and mechanistically unrelated drugs in addition to the drug initially administered. Although extensive work has been done to characterize MDR mechanisms in vitro, the translation of this knowledge to the clinic has not been successful. Therefore, identifying genes and mechanisms critical to the development of MDR in vivo and establishing a reliable method for analyzing highly homologous genes from small amounts of tissue is fundamental to achieving any significant enhancement in our understanding of multidrug resistance mechanisms and could lead to treatments designed to circumvent it. In this study, we use a previously established database that allows the identification of lead compounds in the early stages of drug discovery that are not ABC transporter substrates. We believe this can serve as a model for appraising the accuracy and sensitivity of current methods used to analyze the expression profiles of ABC transporters. We found two platforms to be superior methods for the analysis of expression profiles of highly homologous gene superfamilies. This study also led to an improved database by revealing previously unidentified substrates for ABCB1, ABCC1 and ABCG2, transporters that contribute to multidrug resistance. PMID:19584229

  3. Screening and evaluation of molecular markers linked with the factors affected Verticillium wilt resistance in cotton

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The purpose of this study is to search the consistency of the factors affecting Verticillium wilt resistance and resistant levels in cotton to further study the wilt resistant genes and genetic mechanism of resistance. Method: Thirty-seven pairs of primers derived from Verticillium wilt resistance ...

  4. Rootworm Management with Genetically Modified Corn: Current Status, Potential for Resistance, and a Look Toward the Future

    Technology Transfer Automated Retrieval System (TEKTRAN)

    To delay evolution of insect resistance to transgenic crops producing Bacillus thuringiensis (Bt) toxins, nearby "refuges" of host plants not producing Bt toxins are required in many regions. Such refuges are expected to be most effective in slowing resistance when the toxin concentration in Bt crop...

  5. Can Transcranial Direct Current Stimulation Improve the Resistance Strength and Decrease the Rating Perceived Scale in Recreational Weight-Training Experience?

    PubMed

    Lattari, Eduardo; Andrade, Maria L; Filho, Alberto S; Moura, Antônio M; Neto, Geraldo M; Silva, Júlio G; Rocha, Nuno B; Yuan, Ti-Fei; Arias-Carrión, Oscar; Machado, Sérgio

    2016-12-01

    Lattari, E, Andrade, ML, Filho, AS, Moura, AM, Neto, GM, Silva, JG, Rocha, NB, Yuan, T-F, Arias-Carrión, O, and Machado, S. Can transcranial direct current stimulation improve the resistance strength and decrease the rating perceived scale in recreational weight-training experience? J Strength Cond Res 30(12): 3381-3387, 2016-The goal of this study was to evaluate the acute efficacy of anodic transcranial direct current stimulation on the total volume of repetitions and perceived exertion in recreationally trained individuals in strength. The sample consisted of 10 participants trained in exercise against resistance for at least 3 months. Participants underwent elbow flexion exercise at barbell with a specific load of 10 repetition maximum (10RM), responded immediately after the OMNI-RES scale, and were stimulated for 20 minutes with a tDSC protocol (2 mA), depending on randomization. After applying the tDSC, subjects were again subjected to perform elbow flexion with 10RM load and, soon after, again responded to OMNI-RES scale. All subjects underwent the 3 experimental conditions of the study, c-tDSC, a-tDSC, and sham-tDSC, which were randomized. A range of 48-72 hours was allowed between each assessment visit. An interaction to condition and time (F = 52.395; p ≤ 0.001) has shown that repetitions completed after anodic condition were higher compared with the other conditions in the postsession. In relation to perceived exertion, verified by OMNI-RES scale, 2-way analysis of variance for repeated measures showed an interaction between condition and time (F = 28.445; p ≤ 0.001), where the perceived exertion was decreased after the a-tDSC condition and increased after the c-tDSC condition. In strict terms of performance, it seems to be beneficial to attend a session of 20 minutes a-tDSC, when strength training practitioners can no longer support high-volume training and have increased responses in the perceived exertion.

  6. Cabazitaxel: A novel taxane for metastatic castration-resistant prostate cancer-current implications and future prospects

    PubMed Central

    Abidi, Afroz

    2013-01-01

    Recent advances in the management of prostate cancer have shown considerable development with time and many novel therapeutic agents have been approved over the past years. For patients with metastatic castration-resistant prostate cancer (mCRPC), initially docetaxel was the standard chemotherapy but once they became refractory to docetaxel, no treatment improved survival. This scenario changed in June 2010 when the US Food and Drug Administration (FDA) approved Cabazitaxel as a new therapeutic option for patients with mCRPC resistant to docetaxel. Cabazitaxel, being a novel tubulin-binding taxane with poor affinity for P-glycoprotein, decreases the chances of resistance. It has shown antitumor activity in preclinical, phase I, II and III clinical studies in docetaxel-resistant tumors. This article summarises the background, pharmacodynamic, kinetics and clinical development of cabazitaxel for the treatment of castration-resistant prostate cancer. Future development and rational use of this drug in other tumors is under therapeutic investigation. PMID:24250198

  7. High-Tc planar SQUID gradiometer for eddy current non-destructive evaluation

    NASA Astrophysics Data System (ADS)

    Zhang, Ming-Jian; Lang, Pei-Lin; Peng, Zhi-Hui; Chen, Ying-Fei; Chen, Ke; Zheng, Dong-Ning

    2006-08-01

    This paper reports the fabrication and test of a high-Tc SQUID planar gradiometer which is patterned from YBCO thin film deposited on a SrTiO3 bicrystal substrate. The measurement of noise spectrum at 77K shows that the white noise at 200 Hz is about 1×10-4Φ0/(Hz)1/2. The minimal magnetic gradient is measured and the results suggest that the minimal magnetic gradient is 94 pT/m. The planar gradiometer is used in non-destructive evaluation (NDE) experiments to detect the artifacts in conducting aluminium plates by performing eddy current testing in an unshielded environment. The effect of the exciting coil dimension on the NDE results is investigated. By mapping out the induced field distribution, flaws about 10mm below the plate surface can be clearly identified.

  8. Biomarker approaches in major depressive disorder evaluated in the context of current hypotheses.

    PubMed

    Jentsch, Mike C; Van Buel, Erin M; Bosker, Fokko J; Gladkevich, Anatoliy V; Klein, Hans C; Oude Voshaar, Richard C; Ruhé, Eric G; Eisel, Uli L M; Schoevers, Robert A

    2015-01-01

    Major depressive disorder is a heterogeneous disorder, mostly diagnosed on the basis of symptomatic criteria alone. It would be of great help when specific biomarkers for various subtypes and symptom clusters of depression become available to assist in diagnosis and subtyping of depression, and to enable monitoring and prognosis of treatment response. However, currently known biomarkers do not reach sufficient sensitivity and specificity, and often the relation to underlying pathophysiology is unclear. In this review, we evaluate various biomarker approaches in terms of scientific merit and clinical applicability. Finally, we discuss how combined biomarker approaches in both preclinical and clinical studies can help to make the connection between the clinical manifestations of depression and the underlying pathophysiology.

  9. Eddy current measurement system evaluation for corrosion depth determination on cast aluminum aircraft structure

    NASA Astrophysics Data System (ADS)

    Singh, Surendra; Greving, Dan; Kinney, Andy; Vensel, Fred; Ohm, Jim; Peeler, Mike

    2013-01-01

    An eddy current (EC) technique was developed to determine the corrosion depth on a bare flange face of a cast aluminum A356-T6 aircraft engine structure. The EC response and the corrosion depths determined through metallurgical cross sections were used to develop an empirical relation between EC response and depth. The EC technique and depth determination are used to inspect the engine structures during overhaul to determine if they are fit for continued service. An accurate and reliable Non-Destructive Inspection is required to ensure that structures returned to service are safe for continued operation. NDE system reliability demonstrations of the eddy current technique are traditionally reported in terms of Probability of Detection (POD) data using MIL-HDBK-1823A. However, the calculation of POD data is based on a simple linear predictive model that is valid only if certain criteria are met. These are: 1) NDE system response is measurable (i.e. continuous data), 2) Flaw size is known and measurable (i.e. continuous data), 3) relationship between the NDE system response and flaw size is linear (or linear on a log scale), 4) variation in measured responseresponse around a predicted response for a given flaw size is normally distributed, 5) the variation around the predicted response is constant (i.e. variation does not change with flaw size), and 6) inherent variability in the NDE system is known and fully understood. In this work, a Measurement System Evaluation (MSE) of the Eddy Current System was used to address some of these concerns. This work was completed on two aircraft structures having varying corrosion depths. The data were acquired in a random manner at fifty regions of interests (ROIs). Three operators participated in this study, and each operator measured Eddy Current response three times in each ROI. In total, there were four hundred and fifty data points collected. Following this, the two structures were sectioned for measuring corrosion depth. The

  10. Management of obstetric postpartum hemorrhage: a national service evaluation of current practice in the UK

    PubMed Central

    Al Wattar, Bassel H; Tamblyn, Jennifer A; Parry-Smith, William; Prior, Mathew; Van Der Nelson, Helen

    2017-01-01

    Background Postpartum hemorrhage (PPH) continues to be one of the major causes of maternal mortality and morbidity in obstetrics. Variations in practice often lead to adverse maternity outcomes following PPH. Our objective was to assess the current practice in managing PPH in the UK. Methods We performed a national multicenter prospective service evaluation study over one calendar month and compared the current performance to national standards for managing PPH. We used a standardized data collection tool and collected data on patients’ demographics, incidence of PPH, estimated blood loss (EBL), prophylactic and treatment measures, onset of labor, and mode of delivery. Results We collected data from 98 obstetric units, including 3663 cases of primary PPH. Fifty percent of cases were minor PPH (EBL 500–1000 mL, n=1900/3613, 52.6%) and the remaining were moderate PPH (EBL >1000 to <2000 mL, n=1424/3613, 39.4%) and severe PPH (EBL >2000 mL, n=289/3613, 8%). The majority of women received active management of the third stage of labor (3504/3613, 97%) most commonly with Syntometrine intramuscular (1479/3613, 40.9%). More than half required one additional uterotonic agent (2364/3613, 65.4%) most commonly with Syntocinon intravenous infusion (1155/2364, 48.8%). There was a poor involvement of consultant obstetricians and anesthetists in managing PPH cases, which was more prevalent when managing major PPH (p=0.0001). Conclusion There are still variations in managing PPH in the UK against national guidelines. More senior doctor involvement and regular service evaluation are needed to improve maternal outcomes following PPH. PMID:28176919

  11. Tarnish resistance evaluation of experimental Pd-free Ag-Au-Pt-Cu dental alloys.

    PubMed

    Takuma, Yasuko; Shiraishi, Takanobu; Fujita, Takeshi; Hisatsune, Kunihiro

    2010-05-01

    This study evaluated the tarnish resistance of eight experimental Pd-free Ag-Au-Pt-Cu dental alloys in a 0.1% Na(2)S aqueous solution at 37 degrees C. Color measurements of the plate samples were made using a computerized spectrophotometer before and after immersion in the test solution for up to 72 hours. Tarnish discoloration was evaluated using the color difference vector, DeltaE*, in the CIELAB color space. Microstructural observation of each sample through an optical microscope revealed the matrix phase as the major constituent and second-phase small grains in the matrix phase. Selective tarnish discoloration occurred in the matrix, and fractional area of the matrix to the whole surface area was influenced by the sum of Au and Ag concentrations. The DeltaE* value significantly decreased with increasing Au/(Au+Ag) atomic ratio. In conclusion, the Au/(Au+Ag) ratio in an alloy and the fractional area of the matrix were found to be primary and auxiliary factors affecting the tarnish resistance of the experimental alloys.

  12. Clinical characteristics of resistant hypertension evaluated by ambulatory blood pressure monitoring.

    PubMed

    Kansui, Yasuo; Matsumura, Kiyoshi; Kida, Haruko; Sakata, Satoko; Ohtsubo, Toshio; Ibaraki, Ai; Kitazono, Takanari

    2014-01-01

    Strict control of blood pressure is important to prevent cardiovascular disease, although it is sometimes difficult to decrease blood pressure to target levels. The aim of this study was to investigate the clinical characteristics of resistant hypertension evaluated by ambulatory blood pressure monitoring. One hundred in-hospital patients, whose 24-hour average blood pressure was higher than 130/80 mmHg even after treatment with more than three antihypertensive drugs, were included in the present analysis. Circadian variation of blood pressure was evaluated by nocturnal fall in systolic blood pressure. Average blood pressures of all patients were high in both daytime and nighttime, 150.0/82.9 and 143.8/78.2 mmHg, respectively. Twenty patients had been treated with hemodialysis or peritoneal dialysis. In 63 patients out of the other 80 patients (79%), estimated glomerular filtration rate (eGFR) was also decreased (<60 mL/min/1.73 m²). The patients classified into dipper, non-dipper, riser and extreme-dipper were 20%, 43%, 34% and 3%, respectively. In addition, in 17 patients whose eGFR was preserved, 12 patients showed a non-dipper or riser pattern, suggesting that it was difficult to account for this altered circadian blood pressure variation only by renal dysfunction. These results show that a large number of the patients with resistant hypertension suffered from renal dysfunction, although it was difficult to explain altered circadian blood pressure variation based on renal dysfunction alone.

  13. Detection of Schistosoma mansoni circulating cathodic antigen for evaluation of resistance induced by irradiated cercariae.

    PubMed

    Barsoum, I S; Bogitsh, B J; Colley, D G

    1992-08-01

    The appearance of serum levels of circulating cathodic antigen (CCA) detectable by a monoclonal antibody (mAb) (5H11) antigen-capture sandwich enzyme-linked immunosorbent assay (ELISA) system was evaluated during acute Schistosoma mansoni infections in female CF1 mice exposed to either 100 or 25 cercariae. Measurable CCA levels occurred in these groups at 5 and 7 wk after infection, respectively. The kinetics of appearance of CCA were thus related to the intensity of infection. The level of resistance developed by female C57BL/6 mice upon immunization with irradiated cercariae, as expressed by both worm burden and CCA levels after cercarial challenge was evaluated. Immunization conferred 44% protection against the challenge infection, and the level of CCA detected in the sera of the control group was significantly (P less than 0.02) higher than that found in the sera of the immunized group, 6 wk after challenge. These results demonstrate that CCA detection by the 5H11 mAb antigen-capture sandwich ELISA can reflect vaccine-induced resistance against S. mansoni. Localization studies showed that 5H11 reacts with a CCA epitope in the adult worm gut and to a lesser extent with the male tegument. Adaptations of this and other antigen detection systems may prove useful in monitoring the efficacy of developmental vaccines, an ability that may be essential for the extension of such studies to humans.

  14. Evaluation of Superimposed Sequence Components of Currents based Islanding Detection Scheme during DG Interconnections

    NASA Astrophysics Data System (ADS)

    Sareen, Karan; Bhalja, Bhavesh R.; Maheshwari, Rudra Prakash

    2016-02-01

    A new islanding detection scheme for distribution network containing different types of distributed generations (DGs) is presented in this paper. The proposed scheme is based on acquiring three phase current samples for full cycle duration of each simulation case of islanding/non-islanding conditions at the point of common coupling (PCC) of the targeted DG. Afterwards, superimposed positive & negative sequence components of current are calculated and continuously compared with pre-determined threshold values. Performance of the proposed scheme has been evaluated on diversified islanding and non-islanding events which were generated by modeling standard IEEE 34-bus system using PSCAD/EMTDC software package. The proposed scheme is capable to detect islanding condition rapidly even for perfect power balance situation for both synchronous and inverter based DGs. Furthermore, it remains stable during non-islanding events such as tripping of multiple DGs and different DG interconnection operating conditions. Therefore, the proposed scheme avoids nuisance tripping during diversified non-islanding events. At the end, comparison of the proposed scheme with the existing scheme clearly indicates its advantage over the existing scheme.

  15. Repeated sessions of transcranial direct current stimulation evaluation on fatigue and daytime sleepiness in Parkinson's disease.

    PubMed

    Forogh, Bijan; Rafiei, Maryam; Arbabi, Amin; Motamed, Mohammad Reza; Madani, Seyed Pezhman; Sajadi, Simin

    2017-02-01

    Parkinson is a common and disabling disease that affects patient's and career's quality of life. Unfortunately, medications, such as dopaminergic and sedative-hypnotic drugs, as an effective treatment have unwilling side effects. Recently, Transcranial Direct Current Stimulation (tDCS) in conjunction with medication becomes popular as a complementary safe treatment and several studies have proved its effectiveness on controlling motor and specially non-motor aspects of Parkinson's disease. In this randomized double-blind parallel study, 23 patients with Parkinson's disease divided into two groups of real tDCS plus occupational therapy and sham tDCS plus occupational therapy and the effects of therapeutic sessions (eight sessions tDCS with 0.06 mA/cm(2) current, 20 min on dorsolateral prefrontal cortex) were evaluated on fatigue and daytime sleepiness just after therapeutic course and in 3-month follow-up. tDCS had a significant effect on fatigue and no effect on daytime sleepiness reduction in patients with Parkinson's disease. tDCS is an effective and safe complementary treatment on fatigue reduction in Parkinson's disease.

  16. Evaluation of current techniques for isolation of chars as natural adsorbents

    USGS Publications Warehouse

    Chun, Y.; Sheng, G.; Chiou, C.T.

    2004-01-01

    Chars in soils or sediments may potentially influence the soil/sediment sorption behavior. Current techniques for the isolation of black carbon including chars rely often on acid demineralization, base extraction, and chemical oxidation to remove salts and minerals, humic acid, and refractory kerogen, respectively. Little is known about the potential effects of these chemical processes on the char surface and adsorptive properties. This study examined the effects of acid demineralization, base extraction, and acidic Cr2O72- oxidation on the surface areas, surface acidity, and benzene adsorption characteristics of laboratory-produced pinewood and wheat-residue chars, pure or mixed with soils, and a commercial activated carbon. Demineralization resulted in a small reduction in the char surface area, whereas base extraction showed no obvious effect. Neither demineralization nor base extraction caused an appreciable variation in benzene adsorption and presumably the char surface properties. By contrast, the Cr2O 72- oxidation caused a >31% reduction in char surface area. The Boehm titration, supplemented by FTIR spectra, indicated that the surface acidity of oxidized chars increased by a factor between 2.3 and 12 compared to nonoxidized chars. Benzene adsorption with the oxidized chars was lower than that with the non-oxidized chars by a factor of >8.9; both the decrease in char surface area and the increase in char surface acidity contributed to the reduction in char adsorptive power. Although the Cr 2O72- oxidation effectively removes resistant kerogen, it is not well suited for the isolation of chars as contaminant adsorbents because of its destructive nature. Alternative nondestructive techniques that preserve the char surface properties and effectively remove kerogen must be sought.

  17. [Nutritional screening before surgery for esophageal cancer - current status and evaluation results].

    PubMed

    Shimakawa, Takeshi; Asaka, Shinich; Sagawa, Masano; Shimazaki, Asako; Yamaguchi, Kentaro; Usui, Takebumi; Yokomizo, Hajime; Shiozawa, Shunichi; Yoshimatsu, Kazuhiko; Katsube, Takao; Naritaka, Yoshihiko

    2014-10-01

    The incidence of postoperative complications and mortality are usually higher in patients with preoperative malnutrition. Malnutrition often preexists, particularly in patients undergoing surgery for esophageal cancer, which is substantially invasive. It is therefore important to understand the nutritional condition of patients and actively control perioperative nutrition.Our hospital has been providing nutritional status screening for patients before resection of esophageal cancer, and we report the current status and evaluation results in this article.This screening included 158 patients requiring radical resection of esophageal cancer.Age, comorbidity with diabetes, body mass index(BMI), serum albumin(Alb), Onodera's prognostic nutritional index(PNI), and Glasgow prognostic score(GPS)were used as nutritional indicators to stratify patients for analysis.Evaluation parameters included the incidence of postoperative complications(any complication, pulmonary complications, psychiatric disorder, and anastomotic leakage)and rates of long-term postoperative hospitalization.The analysis indicated that age, BMI, serum Alb, PNI, and GPS are useful for predicting the onset of postoperative complications and prolonged postoperative hospitalization.For such patients, more active nutritional control should be provided.

  18. Evaluation of the current state of distributed watershed nutrient water quality modeling.

    PubMed

    Wellen, Christopher; Kamran-Disfani, Ahmad-Reza; Arhonditsis, George B

    2015-03-17

    Watershed models have been widely used for creating the scientific basis for management decisions regarding nonpoint source pollution. In this study, we evaluated the current state of watershed scale, spatially distributed, process-based, water quality modeling of nutrient pollution. Beginning from 1992, the year when Beven and Binley published their seminal paper on uncertainty analysis in hydrological modeling, and ending in 2010, we selected 257 scientific publications which (i) employed spatially distributed modeling approaches at a watershed scale; (ii) provided predictions of flow, nutrient/sediment concentrations or loads; and (iii) reported fit to measured data. Most "best practices" (optimization, validation, sensitivity, and uncertainty analysis) are not consistently employed during model development. There are no statistically significant differences in model performance among land uses. Studies which used more than one point in space to evaluate their distributed models had significantly lower median values of the Nash-Sutcliffe Efficiency (0.70 vs 0.56, p<0.005, nonparametric Mann-Whitney test), and r2 (p<0.005). This finding suggests that model calibration only to the basin outlet may mask compensation of positive and negative errors of source and transportation processes. We conclude by advocating a number of new directions for distributed watershed modeling, including in-depth uncertainty analysis and the use of additional information, not necessarily related to model end points, to constrain parameter estimation.

  19. Evaluation of a cefoxitin disk diffusion test for the detection of mecA-positive methicillin-resistant Staphylococcus saprophyticus.

    PubMed

    Higashide, Masato; Kuroda, Makoto; Ohkawa, Saburo; Ohta, Toshiko

    2006-06-01

    In order to validate the current Clinical and Laboratory Standards Institute (CLSI) criteria for the detection of mecA-mediated resistance in Staphylococcus saprophyticus, 101 clinical isolates, including 8 mecA-positive isolates, were investigated. All the isolates were in the range of the resistant category for coagulase-negative staphylococci with the 1 microg oxacillin disk diffusion method and agar dilution method, despite 93 isolates (92%) being mecA-negative. On the other hand, the 30 microg cefoxitin disk diffusion method showed clearly distinguishable zone diameters between the mecA-positive and -negative isolates. However, four of the mecA-negative isolates that would be considered resistant were false positive, and the current interpretive criteria of the CLSI may thus require reconsideration. This study suggests that the cefoxitin disk diffusion method could be more suitable than the oxacillin disk diffusion method for detecting mecA-mediated resistance in S. saprophyticus.

  20. Evaluations of an in-house drug resistance method for HIV-1 drug resistance using ViroSeq™ 2.0 genotyping system as a gold standard.

    PubMed

    Chaturbhuj, Devidas N; Deshmukh, Pravin S; Hingankar, Nitin K; Siddhaarth, K; Deshpande, Sohan N; Sen, Sourav; Kabra, Sandhya; Paranjape, Ramesh S; Tripathy, Srikanth P

    2013-04-01

    An in-house method was evaluated for its efficiency to detect the HIV-1 drug resistance mutations. This method was compared with the ViroSeq™ Genotyping System 2.0 (Celera Diagnostics, US) a gold standard. Sixty-five stored plasma samples, previously tested for HIV-1 drug resistance using the ViroSeq™ method were used to evaluate the in-house method. Out of the sixty five plasma samples, sixty were HIV-1 positive clinical samples; four samples from the Virology Quality Assessment (VQA) program and one positive control from the ViroSeq™ kit were used in this study. The sequences generated by the ViroSeq™ and an in-house method showed 99.5±0.5% and 99.7±0.4% (mean±SD) nucleotide and amino acid identity, respectively. Out of 214 Stanford HIVdb listed HIV-1 drug resistance mutations in the protease and reverse transcriptase regions, concordance was observed in 203 (94.9%), partial discordance in 11 (5.1%) and complete discordance was absent. The in-house primers are broadly sensitive in genotyping multiple HIV-1 group M subtypes. The amplification sensitivity of the in-house method was 1000 copies/ml. The evaluation of the in-house method provides results comparable with that of ViroSeq™ method thus, making the in-house method suitable for HIV-1 drug resistance testing in the developing countries.

  1. Nonlinear current-voltage behavior of the isolated resistive switching filamentary channels in CuC nanolayer

    SciTech Connect

    Kim, Doo-In; Yoon, Jaesik; Kim, Young Moon; Kwon, Se Hun; Kim, Kwang Ho; Park, Ju-Bong; Hwang, Hyunsang

    2011-04-11

    Copper-doped amorphous carbon film was prepared by radio frequency reactive magnetron sputtering and their resistive switching behaviors were studied under a conductive atomic force microscope (cAFM). The repetitive scanning over the same area using cAFM with various bias voltages revealed that most of the isolated conductive paths were involved in resistive switching with asymmetric nonlinear I-V characteristics. The observed I-V behavior of nanoscale filamentary channels indicates that electron transfer mechanism of resistive switching filamentary channel in Pt/CuC/Pt is a tunneling between Cu filamentary channel and electrode through the solid electrolyte rather than conduction through fully connected Cu filamentary channel.

  2. Cross-Resistance between Cry1 Proteins in Fall Armyworm (Spodoptera frugiperda) May Affect the Durability of Current Pyramided Bt Maize Hybrids in Brazil

    PubMed Central

    Bernardi, Daniel; Salmeron, Eloisa; Horikoshi, Renato Jun; Bernardi, Oderlei; Dourado, Patrick Marques; Carvalho, Renato Assis; Martinelli, Samuel; Head, Graham P.; Omoto, Celso

    2015-01-01

    , indicates that current Cry1-based maize hybrids face a challenge in managing S. frugiperda in Brazil and highlights the importance of effective insect resistance management for these technologies. PMID:26473961

  3. Evaluation of resistance to aflatoxin contamination in kernels of maize genotypes using a GFP-expressing Aspergillus flavus strain

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Evaluation of resistance or susceptibility of corn inbreds to infection by Aspergillus flavus was evaluated by a kernel screening assay. A GFP-expressing strain of A. flavus was used to accomplish this study to measure fungal spread and aflatoxin levels in real time. Among the four inbreds tested, ...

  4. The inhibitory effect of Zingiber corallinum Hance essential oil on drug-resistant bacteria and evaluation of its acute toxicity

    PubMed Central

    Yang, Ce; Zhou, Lin-Lin; Wang, Hai-Yan; Huang, Su-Na; Liu, Qing; Hu, Shi-Lin; Li, Ting-Rong; Chen, Yan-Bing; Jiang, Jian-Xin

    2011-01-01

    Summary Background The excessive and irregular use of antibiotics could result in the generation and diffusion of drug-resistant bacteria. The aim of this study was to investigate the inhibitory effect of Zingiber corallinum Hance essential oil (ZCHO) on drug-resistant bacteria, especially on drug-resistant Acinetobacter baumannii. Material/Methods Susceptibility testing was used to evaluate the effect of ZCHO on growth inhibition of drug-resistant bacteria by paper disk method. Mice orally administered with ZCHO were used to observe acute toxicity and to determine median lethal dose (LD50) of ZCHO. Broth dilution method was used to determine minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) of ZCHO on drug-resistant Acinetobacter baumannii. Results ZCHO exhibited an obvious inhibitory effect not only on gram-negative drug-resistant bacteria including Escherichia coli, Klebsiella pneumoniae, Enterobacter cloacae and Acinetobacter baumannii, but also on gram-positive drug-resistant bacteria including Staphylococcus aureus, Staphylococcus epidermidis and Staphylococcus haemolyticus. The ZCHO containing 79% terpinen-4-ol revealed better bacteriostatic effect than ZCHO with 34% terpinen-4-ol. The LD50 of ZCHO was 1790.427 mg/kg. The MIC and MBC of ZCHO on drug-resistant Acinetobacter baumannii were 1457.81 mg/L. Conclusions ZCHO has obvious bacteriostasis and bactericidal effects, especially against drug-resistant Acinetobacter baumannii. Therefore, ZCHO is a promising natural bioactive component with antibacterial effect and satisfactory safety due to its low toxicity. PMID:21525802

  5. Current status of anti-human epidermal growth factor receptor 2 therapies: predicting and overcoming herceptin resistance.

    PubMed

    Chung, Alice; Cui, Xiaojiang; Audeh, William; Giuliano, Armando

    2013-08-01

    Human epidermal growth factor receptor 2-overexpressing (HER2+) breast cancer occurs in 20% to 25% of cases and is associated with poor prognosis. Trastuzumab (Herceptin; Genentech, South San Francisco, CA) is a monoclonal antibody targeting the HER2 extracellular domain that has been shown to significantly reduce relapse rates. However, some patients with HER2+ tumors do not respond to Herceptin, and 60% to 85% of patients with HER2+ metastatic breast cancer acquire resistance within a short time period. In this review, we discuss proposed mechanisms of action of trastuzumab and trastuzumab resistance and various drugs that have been developed to overcome drug resistance. We introduce the basal molecular subtype as a predictor of increased risk in HER2+ breast cancer and a possible alternative cause of drug resistance.

  6. A general and precise method to evaluate the series resistance of photovoltaic cells from I-V characteristics

    NASA Astrophysics Data System (ADS)

    Chibbaro, C.; Zimbone, M.; Litrico, G.; Baeri, P.; Lo Trovato, M. L.; Aleo, F.

    2011-08-01

    This paper presents a general method for extracting solar cell parameters from current- voltage characteristics obtained under illumination. In particular, it focuses on the problem of measuring very low values of series resistance with sufficient precision. The method makes use of two different sets of experimental data: a cell current-voltage characteristic measured at a fixed sun irradiance level and a set of short circuit current and open circuit voltage value pairs measured at various sun irradiance levels. The method involves an interplay of different fitting procedures iteratively performed to these two data sets. The method is tested on two single junction silicon cells with the same very low series resistance however, having two very different values of shunt resistance. It is shown that in both cases this method is much more precise and reproducible than other conventional methods.

  7. Electrical resistivity investigation of fluvial geomorphology to evaluate potential seepage conduits to agricultural lands along the San Joaquin River, Merced County, California, 2012–13

    USGS Publications Warehouse

    Groover, Krishangi D.; Burgess, Matthew K.; Howle, James F.; Phillips, Steven P.

    2017-02-08

    Increased flows in the San Joaquin River, part of the San Joaquin River Restoration Program, are designed to help restore fish populations. However, increased seepage losses could result from these higher restoration flows, which could exacerbate existing drainage problems in neighboring agricultural lands and potentially damage crops. Channel deposits of abandoned river meanders that are hydraulically connected to the river could act as seepage conduits, allowing rapid and widespread water-table rise during restoration flows. There is a need to identify the geometry and properties of these channel deposits to assess their role in potential increased seepage effects and to evaluate management alternatives for reducing seepage. Electrical and electromagnetic surface geophysical methods have provided a reliable proxy for lithology in studies of fluvial and hyporheic systems where a sufficient electrical contrast exists between deposits of differing grain size. In this study, direct-current (DC) resistivity was used to measure subsurface resistivity to identify channel deposits and to map their subsurface geometry. The efficacy of this method was assessed by using DC resistivity surveys collected along a reach of the San Joaquin River in Merced County, California, during the summers of 2012 and 2013, in conjunction with borings and associated measurements from a hydraulic profiling tool. Modeled DC resistivity data corresponded with data from cores, hand-auger samples, a hydraulic profiling tool, and aerial photographs, confirming that DC resistivity is effective for differentiating between silt and sand deposits in this setting. Modeled DC resistivity data provided detailed two-dimensional cross-sectional resistivity profiles to a depth of about 20 meters. The distribution of high-resistivity units in these profiles was used as a proxy for identifying areas of high hydraulic conductivity. These data were used subsequently to guide the location and depth of wells

  8. Determining resistivity of a formation adjacent to a borehole having casing by generating constant current flow in portion of casing and using at least two voltage measurement electrodes

    DOEpatents

    Vail, III, William Banning

    2000-01-01

    Methods of operation of different types of multiple electrode apparatus vertically disposed in a cased well to measure information related to the resistivity of adjacent geological formations from within the cased well are described. The multiple electrode apparatus has a minimum of two spaced apart voltage measurement electrodes that electrically engage a first portion of the interior of the cased well and that provide at least first voltage information. Current control means are used to control the magnitude of any selected current that flows along a second portion of the interior of the casing to be equal to a predetermined selected constant. The first portion of the interior of the cased well is spaced apart from the second portion of the interior of the cased well. The first voltage information and the predetermined selected constant value of any selected current flowing along the casing are used in part to determine a magnitude related to the formation resistivity adjacent to the first portion of the interior of the cased well. Methods and apparatus having a plurality of voltage measurement electrodes are disclosed that provide voltage related information in the presence of constant currents flowing along the casing which is used to provide formation resistivity.

  9. Current Evaluation of the Millennium Phytomedicine- Ginseng (I): Etymology, Pharmacognosy, Phytochemistry, Market and Regulations

    PubMed Central

    Jia, Lee; Zhao, Yuqing

    2009-01-01

    The dawning of this millennium broke new ground in life science and technology, presented us genomic and proteomic revolution, nanotechnology innovation, and high performance liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) used for separating and identifying new chemical entities at pico-, or even femto-concentrations. Applications of these high technologies to the traditional Chinese medicine (TCM) opened a new chapter in the ancient medicine, and prompted us to re-evaluate the thousand-year-old phytomedicine–ginseng from current perspectives. We, therefore, collected the latest information (mostly within 10 years) on ginseng, and condensed the information into two parts of this review serial. The present part covers etymology of ginseng, its pharmacognosy (natural origin, physical appearance, chemical properties, and specie identification), its cultivation and processing-related metabolic changes in active ingredients, standardized analytical methods used for quality control of various ginseng products, modern analytical methods used to identify and classify more than 100 chemical entities (many were recently unfolded) derived from ginseng species and their metabolites. The global markets and production of ginseng and relevant government regulations are herein updated to exchange information and understandings about current people’s uses and cultivation of ginseng. The second part of the review serial will classify all these 100 chemical entities separated from various ginseng species into different groups based on their structural similarities, and summarize bioactivities of these entities. The second part of the review serial will also focus on recent findings of ginseng pharmacology and its clinical trials for various diseases, and brief side effects of ginseng. PMID:19601793

  10. An evaluation of the latitudinal gradient of chlorophyll in the California Current

    NASA Astrophysics Data System (ADS)

    Dietrich, W.; Broughton, J.; Kudela, R. M.

    2013-12-01

    Tracking of spatial and temporal trends in phytoplankton abundance and distribution is an important step toward understanding large-scale macroecological processes in the ocean. Measurements of ocean radiance from satellite-borne sensors, such as SeaWiFS and MODIS, can be used to estimate surface chlorophyll concentration, which is a good indicator of phytoplankton biomass. The primary goal of this study was to evaluate the latitudinal gradient in chlorophyll concentration within the California Current first reported by Ware and Thomson (2005). They found that average chlorophyll concentration tended to increase steadily from 32-48°N latitude. This concentration gradient was reevaluated using a longer dataset and an algorithm refined for the region. Radiance data from the MODIS-Aqua instrument were obtained for every year from 2002 through 2013. Data included annual averages of remote sensing radiance as well as monthly averages for February, April, and August. These months were chosen to represent each of the three oceanographic seasons present in the California Current. Estimates of chlorophyll concentration were derived from these data using the CALFIT algorithm developed by Kahru et al. (2012). The resulting maps of chlorophyll concentration were processed in MATLAB and linear regressions were performed using SYSTAT 13 software. A statistically significant (p < 0.05) latitudinal trend in chlorophyll was observed in the annual averaged data as well as in the averaged seasonal data from February and August. No significant trend was observed in the averaged April data. Chlorophyll concentration was positively correlated with latitude in every instance, except in April 2003 and April 2005, where a negative correlation was observed. The positive latitudinal trend was strongest during August and weakest during April. Strong peaks in chlorophyll were observed near San Francisco Bay and the mouth of the Columbia River, suggesting that river-borne nutrient input may be

  11. High-resolution simulations for Vietnam - methodology and evaluation of current climate

    NASA Astrophysics Data System (ADS)

    Katzfey, Jack; Nguyen, Kim; McGregor, John; Hoffmann, Peter; Ramasamy, Suppiah; Nguyen, Hiep Van; Khiem, Mai Van; Nguyen, Thang Van; Truong, Kien Ba; Vu, Thang Van; Nguyen, Hien Thuan; Thuc, Tran; Phong, Doan Ha; Nguyen, Bang Thanh; Phan-Van, Tan; Nguyen-Quang, Trung; Ngo-Duc, Thanh; Trinh-Tuan, Long

    2016-05-01

    To assist the government of Vietnam in its efforts to better understand the impacts of climate change and prioritise its adaptation measures, dynamically downscaled climate change projections were produced across Vietnam. Two Regional Climate Models (RCMs) were used: CSIRO's variable-resolution Conformal-Cubic Atmospheric Model (CCAM) and the limited-area model Regional Climate Model system version 4.2 (RegCM4.2). First, global CCAM simulations were completed using bias- and variance-corrected sea surface temperatures as well as sea ice concentrations from six Coupled Model Intercomparison Project Phase 5 (CMIP5) global climate models. This approach is different from other downscaling approaches as it does not use any atmospheric fields from the GCMs. The global CCAM simulations were then further downscaled to 10 km using CCAM and to 20 km using RegCM4.2. Evaluations of temperature and precipitation for the current climate (1980-2000) were completed using station data as well as various gridded observational datasets. The RCMs were able to reproduce reasonably well most of the important characteristics of observed spatial patterns and annual cycles of temperature. Average and minimum temperatures were well simulated (biases generally less than 1oC), while maximum temperatures had biases of around 1oC. For precipitation, although the RCMs captured the annual cycle, RegCM4.2 was too dry in Oct.-Nov. (-60% bias), while CCAM was too wet in Dec.- Mar. (130% bias). Both models were too dry in summer and too wet in winter (especially in northern Vietnam). The ability of the ensemble simulations to capture current climate increases confidence in the simulations of future climate.

  12. Current evaluation of the millennium phytomedicine--ginseng (I): etymology, pharmacognosy, phytochemistry, market and regulations.

    PubMed

    Jia, Lee; Zhao, Yuqing

    2009-01-01

    The dawning of this millennium broke new ground in life science and technology, presented us genomic and proteomic revolution, nanotechnology innovation, and high performance liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS) used for separating and identifying new chemical entities at pico-, or even femto-concentrations. Applications of these high technologies to the traditional Chinese medicine (TCM) opened a new chapter in the ancient medicine, and prompted us to re-evaluate the thousand-year-old phytomedicine- ginseng from current perspectives. We, therefore, collected the latest information (mostly within 10 years) on ginseng, and condensed the information into two parts of this review serial. The present part covers etymology of ginseng, its pharmacognosy (natural origin, physical appearance, chemical properties, and specie identification), its cultivation and processing-related metabolic changes in active ingredients, standardized analytical methods used for quality control of various ginseng products, modern analytical methods used to identify and classify more than 100 chemical entities (many were recently unfolded) derived from ginseng species and their metabolites. The global markets and production of ginseng and relevant government regulations are herein updated to exchange information and understandings about current people's uses and cultivation of ginseng. The second part of the review serial will classify all these 100 chemical entities separated from various ginseng species into different groups based on their structural similarities, and summarize bioactivities of these entities. The second part of the review serial will also focus on recent findings of ginseng pharmacology and its clinical trials for various diseases, and brief side effects of ginseng.

  13. Evaluation of an expanded microarray for detecting antibiotic resistance genes in a broad range of gram-negative bacterial pathogens.

    PubMed

    Card, Roderick; Zhang, Jiancheng; Das, Priya; Cook, Charlotte; Woodford, Neil; Anjum, Muna F

    2013-01-01

    A microarray capable of detecting genes for resistance to 75 clinically relevant antibiotics encompassing 19 different antimicrobial classes was tested on 132 Gram-negative bacteria. Microarray-positive results correlated >91% with antimicrobial resistance phenotypes, assessed using British Society for Antimicrobial Chemotherapy clinical breakpoints; the overall test specificity was >83%. Microarray-positive results without a corresponding resistance phenotype matched 94% with PCR results, indicating accurate detection of genes present in the respective bacteria by microarray when expression was low or absent and, hence, undetectable by susceptibility testing. The low sensitivity and negative predictive values of the microarray results for identifying resistance to some antimicrobial resistance classes are likely due to the limited number of resistance genes present on the current microarray for those antimicrobial agents or to mutation-based resistance mechanisms. With regular updates, this microarray can be used for clinical diagnostics to help accurate therapeutic options to be taken following infection with multiple-antibiotic-resistant Gram-negative bacteria and prevent treatment failure.

  14. Review and Evaluation of Current Training Programs Found in Various Mining Environments. Final Report. Volume II, Analysis and Recommendations.

    ERIC Educational Resources Information Center

    Adkins, John; And Others

    A project was designed to produce a broad description of current mining training programs and to evaluate their effectiveness with respect to reducing mine injuries. Aggregate training and injury data were used to evaluate the overall training effort at 300 mines as well as specific efforts in 12 categories of training course objectives. From such…

  15. Using plant traits to evaluate the resistance and resilience of ecosystem service provision

    NASA Astrophysics Data System (ADS)

    Kohler, Marina; Devaux, Caroline; Fontana, Veronika; Grigulis, Karl; Lavorel, Sandra; Leitinger, Georg; Schirpke, Uta; Tasser, Erich; Tappeiner, Ulrike

    2015-04-01

    Mountain grassland ecosystems are a hotspot of biodiversity and deliver a multiplicity of ecosystem services. Due to a long history of well adapted agricultural use and specific environmental conditions (e.g. slope, altitude, or climate), various types of grassland ecosystems have developed. Each of them shows specific attributes in forms of plant communities and abiotic characteristics, which lead to particular ranges of ecosystem service provision. However, ongoing climate and societal changes thread plant community composition and may lead to changes in plant traits, and therefore, the provision of ecosystem services. Currently it is not clear how vulnerable these ecosystems are to disturbances, or whether they have developed a high resilience over time. Thus, it is essential to know the ranges of resistance and resilience of an ecosystem service. We, therefore, developed a static approach based on community weighted mean plant traits and abiotic parameters to measure the boundaries of resistance and resilience of each ecosystem service separately. By calculating actual minimum and maximum amounts of ecosystem services, we define the range of resistance of an ecosystem service. We then calculate the potential amount of an ecosystem services (via simulated plant communities) by assuming that no species is lost or added to the system. By comparing actual and potential values, we can estimate whether an ecosystem service is in danger to lose its resilience. We selected different ecosystem services related to mountain grassland ecosystems, e.g. carbon storage, forage quality, forage quantity, and soil fertility. We analysed each ecosystem service for different grassland management types, covering meadows and pastures of very low land-use intensity through to grasslands of high land-use intensity. Results indicate that certain ecosystem services have a higher resilience than others (e.g. carbon storage) for all management types. The ecosystem may provide steady

  16. Self-Rectifying Resistive Switching Memory with Ultralow Switching Current in Pt/Ta2O5/HfO2- x /Hf Stack

    NASA Astrophysics Data System (ADS)

    Ma, Haili; Feng, Jie; Lv, Hangbing; Gao, Tian; Xu, Xiaoxin; Luo, Qing; Gong, Tiancheng; Yuan, Peng

    2017-02-01

    In this study, we present a bilayer resistive switching memory device with Pt/Ta2O5/HfO2- x /Hf structure, which shows sub-1 μA ultralow operating current, median switching voltage, adequate ON/OFF ratio, and simultaneously containing excellent self-rectifying characteristics. The control sample with single HfO2- x structure shows bidirectional memory switching properties with symmetrical I-V curve in low resistance state. After introducing a 28-nm-thick Ta2O5 layer on HfO2- x layer, self-rectifying phenomena appeared, with a maximum self-rectifying ratio (RR) of 4 × 103 observed at ±0.5 V. Apart from being a series resistance for the cell, the Ta2O5 rectifying layer also served as an oxygen reservoir which remains intact during the whole switching cycle.

  17. Effect of surface roughness on leakage current and corrosion resistance of oxide layer on AZ91 Mg alloy prepared by plasma electrolytic oxidation

    NASA Astrophysics Data System (ADS)

    Yoo, Bongyoung; Shin, Ki Ryoung; Hwang, Duck Young; Lee, Dong Heon; Shin, Dong Hyuk

    2010-09-01

    The influence of the surface roughness of Mg alloys on the electrical properties and corrosion resistance of oxide layers obtained by plasma electrolytic oxidation (PEO) were studied. The leakage current in the insulating oxide layer was enhanced by increasing the surface roughness, which is a favorable characteristic for the material when applied to hand-held electronic devices. The variation of corrosion resistance with surface roughness was also investigated. The corrosion resistance was degraded by the increasing surface roughness, which was confirmed with DC polarization and impedance spectroscopy. Pitting corrosion on the passive oxide layer was also analyzed with a salt spray test, which showed that the number of pits was not affected by the surface roughness when the spray time reached 96 h.

  18. Evaluation of cytotoxicity and corrosion resistance of orthodontic mini-implants

    PubMed Central

    Alves, Celha Borges Costa; Segurado, Márcio Nunes; Dorta, Miriam Cristina Leandro; Dias, Fátima Ribeiro; Lenza, Maurício Guilherme; Lenza, Marcos Augusto

    2016-01-01

    ABSTRACT Objective: To evaluate and compare in vitro cytotoxicity and corrosion resistance of mini-implants from three different commercial brands used for orthodontic anchorage. Methods: Six mini-implants (Conexão(tm), Neodent(tm) and SIN(tm)) were separately immersed in artificial saliva (pH 6.76) for 30 and 60 days. The cytotoxicity of the corrosion extracts was assessed in L929 cell cultures using the violet crystal and MTT assays, as well as cell morphology under light microscopy. Metal surface characteristics before and after immersion in artificial saliva were assessed by means of scanning electron microscopy (SEM). The samples underwent atomic absorption spectrophotometry to determine the concentrations of aluminum and vanadium ions, constituent elements of the alloy that present potential toxicity. For statistical analysis, one-way ANOVA/Bonferroni tests were used for comparisons among groups with p < 0.05 considered significant. Statistical analysis was carried out with Graph Pad PRISM software Version 4.0. Results: No changes in cell viability or morphology were observed. Mini-implants SEM images revealed smooth surfaces with no obvious traces of corrosion. The extracts assessed by means of atomic absorption spectrophotometry presented concentrations of aluminum and vanadium ions below 1.0 µg/mL and 0.5 µg/mL, respectively. Conclusion: Orthodontic mini-implants manufactured by Conexão(tm), Neodent(tm) and SIN(tm) present high corrosion resistance and are not cytotoxic. PMID:27901227

  19. Evaluation of some drought resistance criteria at seedling stage in wheat (Triticum aestivum L.) cultivars.

    PubMed

    Tavakol, E; Pakniyat, H

    2007-04-01

    This research was conducted to evaluate some of the drought resistance criteria at seedling stage in wheat. A factorial experiment in a Completely Randomized Design (CRD) was used with two factors consisted of stress levels (0, -5 and -8 bar) using PEG 6000 and genotypes (10 genotypes of bread wheat; Azar 2, Gahar, Koohdasht, Bow, Zagros, Cham, Niknejad, E1 Neilairi, Bohoih and Giza 164) in three replications in a hydroponic condition. Stress Tolerance Index (STI), Water Use Efficiency (WUE), Biological Yield (BY), Shoot Dry Weight (SDW), Root Dry Weight (RDW), Root/Shoot weight ratio (R/S), Root Length (RL), Relative Water Content (RWC), Wilting Percentage (WP) and first and 2nd Leaves Extention Rate (LER1 and LER2) were measured at seedling stage. Increasing stress levels caused reduction in BY, SDW, RDW, RL, RWC, LER1 and LER2, but an increase in WUE, DWR, R/S and WP. Azar2, Gahar, Koohdasht, Zagros and Bow were in favorite condition in regard to STI, WUE and other criteria. Therefore, they are drought tolerant and might be suitable genotypes at water deficit conditions. Niknejad, E1 Neilairi and Cham were moderate and Giza 164 and Bohoih were sensitive genotypes to drought conditions. This research revealed that at -5 bar, WUE, BY, SDW, R/S and LER2 and at -8 bar, WUE, BY and WP were suitable criteria for selection of drought resistant genotypes at seedling stage.

  20. Evaluation of candidate oxidation resistant materials for space applications in LEO

    SciTech Connect

    Rutledge, S.; Banks, B.; Difilippo, F.; Brady, J.; Dever, T.; Hotes, D.

    1986-01-01

    Ground based testing of materials considered for polyimide (Kapton) solar array blanket protection and graphite-epoxy stroctural member protection was performed in an RF plasma asher. Protective coatings on Kapton from various commercial sources and from NASA Lewis Research Center were exposed to the air plasma; and mass loss per unit area was measured for each sample. All samples evaluated provided some protection to the underlying surface, but metal-oxide-fluoropolymer coatings provided the best protection by exhibiting very little degradation after 47 hr of asher exposure. Mica paint was evaluated as a protective coating for graphite-epoxy structural members. Mica appeared to be resistant to attack by atomic oxygen, but only offered limited protection as a paint. this is believed to be due to the paint vehicle ashing underneath the mica leaving unattached mica flakes lying on the surface. The protective coatings on Kapton evaluated so far are promising but further research on protection of graphite-epoxy support structures is needed.

  1. An evaluation of candidate oxidation resistant materials for space applications in LEO

    NASA Technical Reports Server (NTRS)

    Rutledge, Sharon; Banks, Bruce; Difilippo, Frank; Brady, Joyce; Dever, Therese; Hotes, Deborah

    1986-01-01

    Ground based testing of materials considered for polyimide (Kapton) solar array blanket protection and graphite-epoxy stroctural member protection was performed in an RF plasma asher. Protective coatings on Kapton from various commercial sources and from NASA Lewis Research Center were exposed to the air plasma; and mass loss per unit area was measured for each sample. All samples evaluated provided some protection to the underlying surface, but metal-oxide-fluoropolymer coatings provided the best protection by exhibiting very little degradation after 47 hr of asher exposure. Mica paint was evaluated as a protective coating for graphite-epoxy structural members. Mica appeared to be resistant to attack by atomic oxygen, but only offered limited protection as a paint. this is believed to be due to the paint vehicle ashing underneath the mica leaving unattached mica flakes lying on the surface. The protective coatings on Kapton evaluated so far are promising but further research on protection of graphite-epoxy support structures is needed.

  2. Evaluation of Machine Learning and Rules-Based Approaches for Predicting Antimicrobial Resistance Profiles in Gram-negative Bacilli from Whole Genome Sequence Data.

    PubMed

    Pesesky, Mitchell W; Hussain, Tahir; Wallace, Meghan; Patel, Sanket; Andleeb, Saadia; Burnham, Carey-Ann D; Dantas, Gautam

    2016-01-01

    The time-to-result for culture-based microorganism recovery and phenotypic antimicrobial susceptibility testing necessitates initial use of empiric (frequently broad-spectrum) antimicrobial therapy. If the empiric therapy is not optimal, this can lead to adverse patient outcomes and contribute to increasing antibiotic resistance in pathogens. New, more rapid technologies are emerging to meet this need. Many of these are based on identifying resistance genes, rather than directly assaying resistance phenotypes, and thus require interpretation to translate the genotype into treatment recommendations. These interpretations, like other parts of clinical diagnostic workflows, are likely to be increasingly automated in the future. We set out to evaluate the two major approaches that could be amenable to automation pipelines: rules-based methods and machine learning methods. The rules-based algorithm makes predictions based upon current, curated knowledge of Enterobacteriaceae resistance genes. The machine-learning algorithm predicts resistance and susceptibility based on a model built from a training set of variably resistant isolates. As our test set, we used whole genome sequence data from 78 clinical Enterobacteriaceae isolates, previously identified to represent a variety of phenotypes, from fully-susceptible to pan-resistant strains for the antibiotics tested. We tested three antibiotic resistance determinant databases for their utility in identifying the complete resistome for each isolate. The predictions of the rules-based and machine learning algorithms for these isolates were compared to results of phenotype-based diagnostics. The rules based and machine-learning predictions achieved agreement with standard-of-care phenotypic diagnostics of 89.0 and 90.3%, respectively, across twelve antibiotic agents from six major antibiotic classes. Several sources of disagreement between the algorithms were identified. Novel variants of known resistance factors and

  3. Evaluation of Machine Learning and Rules-Based Approaches for Predicting Antimicrobial Resistance Profiles in Gram-negative Bacilli from Whole Genome Sequence Data

    PubMed Central

    Pesesky, Mitchell W.; Hussain, Tahir; Wallace, Meghan; Patel, Sanket; Andleeb, Saadia; Burnham, Carey-Ann D.; Dantas, Gautam

    2016-01-01

    The time-to-result for culture-based microorganism recovery and phenotypic antimicrobial susceptibility testing necessitates initial use of empiric (frequently broad-spectrum) antimicrobial therapy. If the empiric therapy is not optimal, this can lead to adverse patient outcomes and contribute to increasing antibiotic resistance in pathogens. New, more rapid technologies are emerging to meet this need. Many of these are based on identifying resistance genes, rather than directly assaying resistance phenotypes, and thus require interpretation to translate the genotype into treatment recommendations. These interpretations, like other parts of clinical diagnostic workflows, are likely to be increasingly automated in the future. We set out to evaluate the two major approaches that could be amenable to automation pipelines: rules-based methods and machine learning methods. The rules-based algorithm makes predictions based upon current, curated knowledge of Enterobacteriaceae resistance genes. The machine-learning algorithm predicts resistance and susceptibility based on a model built from a training set of variably resistant isolates. As our test set, we used whole genome sequence data from 78 clinical Enterobacteriaceae isolates, previously identified to represent a variety of phenotypes, from fully-susceptible to pan-resistant strains for the antibiotics tested. We tested three antibiotic resistance determinant databases for their utility in identifying the complete resistome for each isolate. The predictions of the rules-based and machine learning algorithms for these isolates were compared to results of phenotype-based diagnostics. The rules based and machine-learning predictions achieved agreement with standard-of-care phenotypic diagnostics of 89.0 and 90.3%, respectively, across twelve antibiotic agents from six major antibiotic classes. Several sources of disagreement between the algorithms were identified. Novel variants of known resistance factors and

  4. A computer simulation study to evaluate resistance development with a derquantel-abamectin combination on UK sheep farms.

    PubMed

    Learmount, J; Taylor, M A; Bartram, D J

    2012-06-08

    UK guidelines for the sustainable control of parasites in sheep (SCOPS) aim to delay further development of anthelmintic drug resistance. This study describes a computer model evaluation of resistance development with a novel oral formulation of derquantel-abamectin, to inform recommendations for use. Two different farm management scenarios, based on UK field data, were modelled to simulate low refugia (non SCOPS) or high refugia (SCOPS) worm populations. The effect on resistance allele frequencies and field efficacy of several treatment scenarios using the novel active derquantel (DQL), a spiroindole (SI), as either a single or multiple active formulation with abamectin (ABA), a macrocyclic lactone (ML), under the two farm management systems was evaluated. The initial resistance allele frequency for DQL was set at 0.0001, assuming that resistance in the UK is low, and for ML at 0.165 or 0.8, assuming that resistant nematode populations exist in the UK. DQL resistance reached a level at which a reduction in field efficacy might be detected (resistance allele frequency 0.25) by year 16 when used sequentially, and by year 31 when used in annual rotation (ABA) with SCOPS management inputs, and by year 5 (sequential) and by year 10 (annual rotation) with non SCOPS management inputs. ML resistance reached a level at which a reduction in ABA field efficacy might be detected (resistance allele frequency 0.25) by year 4 when used sequentially, and by year 8 when used in annual rotation with DQL and SCOPS management inputs, and by year 1 (sequential) and by year 2 (annual rotation) with non SCOPS management inputs. No detectable reduction in field efficacy was observed for DQL-ABA after 40 years of use with SCOPS management inputs for simulations using an initial ML resistance allele frequency of 0.165 and 0.8. A detectable reduction in field efficacy was observed for DQL-ABA by year 32 (initial ML resistance allele frequency=0.165) and by year 6 (initial ML resistance

  5. International evaluation of current and future requirements for environmental engineering education.

    PubMed

    Morgenroth, E; Daigger, G T; Ledin, A; Keller, J

    2004-01-01

    The field of environmental engineering is developing as a result of changing environmental requirements. In response, environmental engineering education (E3) needs to ensure that it provides students with the necessary tools to address these challenges. In this paper the current status and future development of E3 is evaluated based on a questionnaire sent to universities and potential employers of E3 graduates. With increasing demands on environmental quality, the complexity of environmental engineering problems to be solved can be expected to increase. To find solutions environmental engineers will need to work in interdisciplinary teams. Based on the questionnaire there was a broad agreement that the best way to prepare students for these future challenges is to provide them with a fundamental education in basic sciences and related engineering fields. Many exciting developments in the environmental engineering profession will be located at the interface between engineering, science, and society. Aspects of all three areas need to be included in E3 and the student needs to be exposed to the tensions associated with linking the three.

  6. Current practices and evaluation of screening solid organ donors for West Nile virus.

    PubMed

    Nett, R J; Kuehnert, M J; Ison, M G; Orlowski, J P; Fischer, M; Staples, J E

    2012-06-01

    The first cases of West Nile virus (WNV) transmitted through solid organ transplantation (SOT) were identified in 2002. Subsequently, 5 additional clusters have been reported to public health officials in the United States. Based upon a limited number of known cases, patients who acquire WNV from infected donor organs might be at higher risk for severe neurologic disease and death, compared with patients infected through mosquito bites. In response, some organ procurement organizations (OPOs) have instituted pre-transplant screening of organ donors for WNV infection. We evaluated the current practices, concerns, and challenges related to screening organ donors for WNV in the United States by reviewing the relevant medical literature and interviewing key stakeholders. Screening organ donors for WNV is not required by national policy. In 2008, 11 (19%) of 58 OPOs performed WNV screening using nucleic acid amplification testing (NAT). These OPOs differ in their screening strategies, NAT performed, and logistical challenges. Concerns of delays in receiving NAT results before transplant and potential false-positive results leading to organ wasting are limitations to more widespread screening. Furthermore, it is unknown if WNV screening practices decrease SOT-related morbidity and mortality, or if screening is cost-effective. Additional data are needed to assess and improve transplant outcomes related to WNV.

  7. Evaluation of engineered nanoparticle toxic effect on wastewater microorganisms: current status and challenges.

    PubMed

    Eduok, S; Martin, B; Villa, R; Nocker, A; Jefferson, B; Coulon, F

    2013-09-01

    The use of engineered nanoparticles (ENPs) in a wide range of products is associated with an increased concern for environmental safety due to their potential toxicological and adverse effects. ENPs exert antimicrobial properties through different mechanisms such as the formation of reactive oxygen species, disruption of physiological and metabolic processes. Although there are little empirical evidences on environmental fate and transport of ENPs, biosolids in wastewater most likely would be a sink for ENPs. However, there are still many uncertainties in relation to ENPs impact on the biological processes during wastewater treatment. This review provides an overview of the available data on the plausible effects of ENPs on AS and AD processes, two key biologically relevant environments for understanding ENPs-microbial interactions. It indicates that the impact of ENPs is not fully understood and few evidences suggest that ENPs could augment microbial-mediated processes such as AS and AD. Further to this, wastewater components can enhance or attenuate ENPs effects. Meanwhile it is still difficult to determine effective doses and establish toxicological guidelines, which is in part due to variable wastewater composition and inadequacy of current analytical procedures. Challenges associated with toxicity evaluation and data interpretation highlight areas in need for further research studies.

  8. Development of an electromagnetic microscope for eddy-current evaluation of materials. Annual technical report

    SciTech Connect

    Podney, W.N.

    1991-08-01

    Superconductive quantum interference devices (SQUIDs) offer new technology for locating material flaws electromagnetically that promises to increase sensitivity and depth of field as well as to enhance resolution and imaging. The ultrahigh sensitivity of SQUIDs to magnetic flux allows use of microscopic pickup loops in a gradiometer configuration to give high resolution. To realize the advantages of SQUID technology for Air Force requirements in evaluating the integrity of airframes, SQM Technology, Inc. is developing an electromagnetic microscope that uses an array of microscopic pickup loops for imaging micro flaws in aluminum. The prototype comprises a triangular array of microscopic gradiometers that are coupled to SQUID sensors through a flexible, cryogenic umbilical, which enables convenient scanning. Development to date shows three main accomplishments: (1) a planar, azimuthal gradiometer configuration enables suppressing source interference, (2) instrument noise at drive currents of 1 A or so at frequencies below a few kilohertz is of the order of SQUID noise, and (3) a cryogenic umbilical can provide adequate cooling over a four to six foot length.

  9. A review on bioadhesive buccal drug delivery systems: current status of formulation and evaluation methods

    PubMed Central

    Chinna Reddy, P; Chaitanya, K.S.C.; Madhusudan Rao, Y.

    2011-01-01

    Owing to the ease of the administration, the oral cavity is an attractive site for the delivery of drugs. Through this route it is possible to realize mucosal (local effect) and transmucosal (systemic effect) drug administration. In the first case, the aim is to achieve a site-specific release of the drug on the mucosa, whereas the second case involves drug absorption through the mucosal barrier to reach the systemic circulation. The main obstacles that drugs meet when administered via the buccal route derive from the limited absorption area and the barrier properties of the mucosa. The effective physiological removal mechanisms of the oral cavity that take the formulation away from the absorption site are the other obstacles that have to be considered. The strategies studied to overcome such obstacles include the employment of new materials that, possibly, combine mucoadhesive, enzyme inhibitory and penetration enhancer properties and the design of innovative drug delivery systems which, besides improving patient compliance, favor a more intimate contact of the drug with the absorption mucosa. This presents a brief description of advantages and limitations of buccal drug delivery and the anatomical structure of oral mucosa, mechanisms of drug permeation followed by current formulation design in line with developments in buccal delivery systems and methodology in evaluating buccal formulations. PMID:23008684

  10. Disease Management Evaluation: A Comprehensive Review of Current State of the Art.

    PubMed

    Conklin, Annalijn; Nolte, Ellen

    2011-01-01

    Many countries across Europe and elsewhere have been experimenting with various structured approaches to manage patients with chronic illness as a way to improve quality of care, reduce costs and lead to better population health outcomes in the long run. Despite a body of studies of disease management interventions, uncertainty about the effects of these remains not least because current guidance on evaluation methods and metrics require further development to enhance scientific rigour while also being practical in routine operations. This article provides details from a report that reviews the academic and grey literature to help advance the task of improving the science of assessing disease management initiatives in Europe. Challenges identified are methodological, analytical and conceptual in nature, with a key issue being the establishment of the counterfactual. An array of sophisticated statistical techniques and analytical frameworks can assist in the construction of a sound comparison strategy when a randomised controlled trial is not possible. Issues to consider include: a clear framework of the mechanisms of action and expected effects of disease management; an understanding of the characteristics of disease management (scope, content, dose, context), and of the intervention and target populations (disease type, severity, case-mix); a period of observation over multiple years; and a logical link between performance measures and the intervention's aims and underlying theory of behaviour change.

  11. Capacitively coupled and direct-current resistivity surveys of selected reaches of Cozad, Thirty-Mile, Orchard-Alfalfa, Kearney, and Outlet Canals in Nebraska, 2012-13

    USGS Publications Warehouse

    Hobza, Christopher M.; Burton, Bethany L.; Lucius, Jeffrey E.; Tompkins, Ryan E.

    2014-01-01

    Understanding the spatial characteristics of leakage from canals is critical to effectively managing and utilizing water resources for irrigation and hydroelectric purposes. Canal leakage in some parts of Nebraska is the primary source of water for groundwater recharge and helps maintain the base flow of streams. Because surface-water supplies depend on the streamflow of the Platte River and the available water stored in upstream reservoirs, water managers seek to minimize conveyance losses, which can include canal leakage. The U.S. Geological Survey, in cooperation with the Central Platte Natural Resources District and Nebraska Public Power District, used capacitively coupled (CC) and direct-current (DC) resistivity techniques for continuous resistivity profiling to map near-surface lithologies near and underlying the Cozad, Thirty-Mile, Orchard-Alfalfa, Kearney, and Outlet Canals. Approximately 84 kilometers (km) of CC-resistivity data were collected along the five canals. The CC-resistivity data were compared with results from continuous sediment cores and electrical conductivity logs. Generally, the highest resistivities were recorded at the upstream reaches of the Cozad, Thirty-Mile, and Orchard-Alfalfa canals where flood-plain deposits of silt and clay mantle coarser channel deposits of sand and gravel. The finer grained deposits gradually thicken with increasing distance away from the Platte River. Consequently, for many surveyed reaches the thickness of fine-grained deposits exceeded the 8-meter depth of investigation. A detailed geophysical investigation along a 5-km reach of the Outlet Canal southwest of North Platte, Nebraska, used CC and DC resistivity to examine the condition of a compacted-core bank structure and characterized other potential controls on areas of focused seepage. CC-resistivity data, collected along the 5-km study reach, were compared with continuous sediment cores and DC-resistivity data collected near a selected seep near Outlet

  12. Evaluation of the antibacterial activity of Chilean plants traditionally used for wound healing therapy against multidrug-resistant Staphylococcus aureus.

    PubMed

    Holler, Jes Gitz; Søndergaard, Karen; Slotved, Hans-Christian; Gúzman, Alfonso; Mølgaard, Per

    2012-01-01

    Anti-staphylococcal activity of Chilean medicinal plants traditionally used by the Huilliche people for wound healing therapy was evaluated against nine Staphylococcus aureus strains. Three extracts of 26 plant samples (20 species) were evaluated by agar overlay bioautography and MIC determination. Total phenolics and tannins were determined, and the antibacterial contribution of the latter was evaluated. The diffusion assay showed that 17 species were active against susceptible S. AUREUS and that 15 species were active against resistant S. aureus. Removal of tannins from extracts rendered only six species active. MIC-determination showed that 20 extracts had antibacterial activity on all eight strains, and the most potent MIC value was 64 µg/mL. Remarkably, 37 extracts were active against the otherwise multidrug-resistant vanthida strain. Our findings support the wound healing properties of Huilliche medicinal plants and the hypothesis that these plants are promising sources of potential anti-staphylococcal agents towards multidrug-resistant strains.

  13. Evaluating the mobility potential of antibiotic resistance genes in environmental resistomes without metagenomics

    PubMed Central

    Pärnänen, Katariina; Karkman, Antti; Tamminen, Manu; Lyra, Christina; Hultman, Jenni; Paulin, Lars; Virta, Marko

    2016-01-01

    Antibiotic resistance genes are ubiquitous in the environment. However, only a fraction of them are mobile and able to spread to pathogenic bacteria. Until now, studying the mobility of antibiotic resistance genes in environmental resistomes has been challenging due to inadequate sensitivity and difficulties in contig assembly of metagenome based methods. We developed a new cost and labor efficient method based on Inverse PCR and long read sequencing for studying mobility potential of environmental resistance genes. We applied Inverse PCR on sediment samples and identified 79 different MGE clusters associated with the studied resistance genes, including novel mobile genetic elements, co-selected resistance genes and a new putative antibiotic resistance gene. The results show that the method can be used in antibiotic resistance early warning systems. In comparison to metagenomics, Inverse PCR was markedly more sensitive and provided more data on resistance gene mobility and co-selected resistances. PMID:27767072

  14. Differences in the effects of turns and constrictions on the resistive response in current-biased superconducting wire after single photon absorption

    NASA Astrophysics Data System (ADS)

    Zotova, A. N.; Y Vodolazov, D.

    2013-07-01

    We study how turns and constrictions affect the resistive response of superconducting wire after instantaneous, localized heating, by modeling the absorption of a single photon by the wire. We find that the presence of constrictions favors the detection of photons with a range of energies whereas the presence of turns increases the ability to detect only relatively ‘low’ energy photons. The main reason is that in the case of a constriction the current density is increased over the whole length and width of the constriction while in the case of a turn the current density is enhanced only near the inner corner of the turn. This results in inhomogeneous Joule heating near the turn and worsens the conditions for the appearance of the normal domain at relatively small currents, where the ‘high’ energy photons could already create a normal domain in the straight part of the wire. We also find that the amplitude of the voltage pulse depends on the location at which the photon is absorbed, being smallest when the photon is absorbed near the turn and largest when the photon is absorbed near the constriction. This effect is due to the difference in the resistance of constrictions and turns in the normal state from the resistance of the rest of the wire.

  15. Effect of Welding Current on the Structure and Properties of Resistance Spot Welded Dissimilar (Austenitic Stainless Steel and Low Carbon Steel) Metal Joints

    NASA Astrophysics Data System (ADS)

    Shawon, M. R. A.; Gulshan, F.; Kurny, A. S. W.

    2015-04-01

    1.5 mm thick sheet metal coupons of austenitic stainless steel and plain low carbon steel were welded by resistance spot welding technique. The effects of welding current in the range 3-9 kA on the structure and mechanical properties of welded joint were investigated. The structure was studied by macroscopic, microscopic and scanning electron microscopy techniques. Mechanical properties were determined by tensile testing and microhardness measurements. Asymmetrical shape weld nugget was found to have formed in the welded joint which increased in size with an increase in welding current. The fusion zone showed cast structure with coarse columnar grain and dendritic with excess delta ferrite in austenitic matrix. Microhardness of the weld nugget was maximum because of martensite formation. An increase in welding current also increased tensile strength of the weld coupon. An attempt has also been made to relate the mode of fracture with the welding current.

  16. Judicious Toggling of mTOR Activity to Combat Insulin Resistance and Cancer: Current Evidence and Perspectives

    PubMed Central

    Ong, Pei Shi; Wang, Louis Z.; Dai, Xiaoyun; Tseng, Sheng Hsuan; Loo, Shang Jun; Sethi, Gautam

    2016-01-01

    The mechanistic target of rapamycin (mTOR), via its two distinct multiprotein complexes, mTORC1, and mTORC2, plays a central role in the regulation of cellular growth, metabolism, and migration. A dysregulation of the mTOR pathway has in turn been implicated in several pathological conditions including insulin resistance and cancer. Overactivation of mTORC1 and disruption of mTORC2 function have been reported to induce insulin resistance. On the other hand, aberrant mTORC1 and mTORC2 signaling via either genetic alterations or increased expression of proteins regulating mTOR and its downstream targets have contributed to cancer development. These underlined the attractiveness of mTOR as a therapeutic target to overcome both insulin resistance and cancer. This review summarizes the evidence supporting the notion of intermittent, low dose rapamycin for treating insulin resistance. It further highlights recent data on the continuous use of high dose rapamycin analogs and related second generation mTOR inhibitors for cancer eradication, for overcoming chemoresistance and for tumor stem cell suppression. Within these contexts, the potential challenges associated with the use of mTOR inhibitors are also discussed. PMID:27826244

  17. Evaluation of an EMITEC resistively heated metal monolith catalytic converter on two M100 neat methanol-fueled vehicles

    NASA Astrophysics Data System (ADS)

    Piotrowski, Gregory K.; Schaefer, Ronald M.

    1992-12-01

    The report describes the evaluation of a resistively heated catalyst system on two different methanol fueled vehicles. The EMITEC catalyst consisted of a compact resistively heated metal monolith in front of a larger conventional main converter. The EMITEC catalyst was evaluated on two neat methanol-fueled vehicles, a 1981 Volkswagen Rabbit and a 1988 Toyota Corolla. Emission testing was conducted over the Federal Test Procedure (FTP) CVS-75 test cycle. The emissions of primary interest were cold start methanol (unburned fuel), carbon monoxide, and formaldehyde.

  18. Evaluation of cefoxitin disk diffusion breakpoint for detection of methicillin resistance in Staphylococcus pseudintermedius isolates from dogs.

    PubMed

    Bemis, David A; Jones, Rebekah D; Videla, Ricardo; Kania, Stephen A

    2012-09-01

    Cefoxitin disk diffusion susceptibility testing is a recommended screening method for the detection of methicillin resistance in human isolates of Staphylococcus aureus and coagulase-negative staphylococci. A retrospective analysis of 1,146 clinical isolates of Staphylococcus pseudintermedius from dogs was conducted to determine if screening by the cefoxitin disk method can be similarly useful with S. pseudintermedius. The distribution of cefoxitin growth inhibition zone diameters within this collection was bimodal and correlated well with the results of methicillin resistance gene (mecA) detection by polymerase chain reaction. Of the isolates, 5% had discordant results and, when retested, 84% of these were in agreement. While a greater diversity of isolates and interlaboratory comparisons must be tested, the current study suggests that an epidemiological breakpoint (of approximately ≤ 30 mm = resistant; ≥ 31 = susceptible) can be established to predict methicillin resistance in S. pseudintermedius.

  19. Electrochemical evaluation of sulfur poisoning in a methane-fuelled solid oxide fuel cell: Effect of current density and sulfur concentration

    NASA Astrophysics Data System (ADS)

    Hagen, Anke; Johnson, Gregory B.; Hjalmarsson, Per

    2014-12-01

    A Ni/ScYSZ based SOFC was tested at 1, 0.5, 0.25, and 0 (OCV) A cm-2 in methane fuel containing 0-100 ppm H2S. Analysis of cell voltage loss during short-term H2S poisoning showed that SOFC performance loss was generally larger at higher current loads. Separating the effect of H2S on catalytic reforming and electrochemical activity by evaluating the relevant area specific resistances and charge transfer processes based on impedance spectroscopy revealed that the poisoning of electrochemical activity was not dependent on current density. Two major anode processes were significantly affected by the presence of H2S in the fuel; the lower frequency mass transfer/fuel reforming processes and higher frequency charge transfer/triple phase boundary (TPB) processes. At high current densities (0.5 and 1 A cm-2), mass transfer/fuel reforming processes were the most sensitive to sulfur poisoning. At OCV, the effect of sulfur was less pronounced on mass transfer/fuel reforming processes but quite significant on the charge transfer/TPB processes. Overall, sulfur related performance loss was more severe at the highest current density (1 A cm-2), due to the deactivation of catalytic fuel reforming reactions in the anode, leading to less available fuel and a higher fuel utilization. All poisoning effects were reversible after removing H2S from the fuel.

  20. Evaluation of susceptibility test breakpoints used to predict mecA-mediated resistance in Staphylococcus pseudintermedius isolated from dogs.

    PubMed

    Bemis, David A; Jones, Rebekah D; Frank, Linda A; Kania, Stephen A

    2009-01-01

    Clinical and Laboratory Standards Institute interpretive breakpoints for in vitro susceptibility tests that predict mecA-mediated oxacillin resistance in Staphylococcus pseudintermedius isolates from animals have been changed twice in the past decade. Moreover, there are no counterpart recommendations for human isolates of S. pseudintermedius. Individual medical and veterinary laboratories variably use interpretive breakpoints identical to those recommended for use with Staphylococcus aureus or identical to those recommended for use with coagulase-negative staphylococci. The purpose of the current study was to examine correlations between oxacillin disk diffusion, oxacillin gradient diffusion, oxacillin microbroth dilution, and cefoxitin disk diffusion tests used to predict mecA-mediated resistance in S. pseudintermedius and to retrospectively estimate, from disk diffusion zone diameter measurements, the prevalence and rate of increase of oxacillin resistance among canine S. pseudintermedius isolates submitted to a veterinary teaching hospital laboratory. Oxacillin disk diffusion zone diameters of or=0.5 microg/ml were highly correlated with detection of mecA in canine S. pseudintermedius isolates by polymerase chain reaction. MecA-mediated resistance among S. pseudintermedius isolates from dogs increased from less than 5% in 2001 to near 30% in 2007. More than 90% of the methicillin-resistant S. pseudintermedius isolates in 2006 and 2007 were also resistant to representatives of >or=4 additional antimicrobial drug classes. Cefoxitin disk diffusion with the resistance breakpoint set at

  1. Evaluating spin-on carbon materials at low temperatures for high wiggling resistance

    NASA Astrophysics Data System (ADS)

    Weigand, Michael; Krishnamurthy, Vandana; Wang, Yubao; Lin, Qin; Guerrero, Douglas; Simmons, Sean; Carr, Brandy

    2013-03-01

    Spin-on carbon (SOC) materials play an important role in the multilayer lithography scheme for the mass production of advanced semiconductor devices. One of the SOC's key roles in the multilayer process (photoresist, silicon-containing hardmask, SOC) is the reactive ion etch (RIE) for pattern transfer into the substrate. As aspect ratios of the SOC material increase and feature sizes decrease, the pattern transfer from SOC to substrate by a fluorine-containing RIE induces severe pattern deformation ("wiggling"), which ultimately prevents successful pattern transfer into the substrate. One process that reduces line wiggling is a high-temperature (>250°C) post-application bake of the SOC material. In this study, we developed a process for evaluating SOC materials with respect to their pattern transfer performance. This process allowed us to evaluate line-wiggling behavior with several SOC materials at lower bake temperatures. This paper will discuss novel materials design in relation to high-aspect-ratio SOC layers and wiggling resistance.

  2. Evaluation of turfgrass species and cultivars for potential resistance to twolined spittlebug (Hemiptera: Cercopidae).

    PubMed

    Shortman, S L; Braman, S K; Duncan, R R; Hanna, W W; Engelke, M C

    2002-04-01

    Potential resistance to the twolined spittlebug, Prosapia bicincta (Say), was evaluated among 56 turfgrass genotypes. Greenhouse, laboratory, and field bioassays identified differences in spittlebug survival and development, host preference and damage levels, and turfgrass tolerance to and ability to recover from pest induced injury. All centipede grasses demonstrated high levels of susceptibility, followed by bermudagrasses, seashore paspalums, and zoysiagrasses. Average nymphal survival to the adult stage ranged from 1.5 to 78.1%. Development required 38.1-62.0 d under greenhouse conditions, depending on plant taxa. Among seashore paspalums, nymphal survival to the adult stage was lowest and duration of development was longest on HI-1, 'Sea Isle 2000', 561-79, and 'Mauna Kea'. Reduced spittlebug survival and increased developmental times were also observed on the bermudagrasses BERPC 91-15 and 'Tifway'. Although zoysiagrasses supported spittlebug development and survival to the adult stage, developmental times were extended on the zoysiagrass cultivars 'Emerald' and 'El Toro'. Spittlebug preference varied with generation evaluated. First-generation spittlebugs inflicted the greatest damage on TC201 (centipede grass), 'Primavera' (bermudagrass), and 'Emerald' (zoysiagrass) in choice tests. In the fall, second-generation spittlebugs damaged TC201 (centipedegrass) and 'Sea Isle 1' (paspalum) most severely, whereas 561-79 (paspalum) and 'Emerald'(zoysiagrass) were less severely affected. Among taxa included in field trials, HI-1, 'Mauna Kea', 'Sea Isle 2000',and AP-14 paspalums, 'Tifway' bermudagrass, and 'Emerald' zoysiagrass were most tolerant (demonstrated the best regrowth potential following twolined spittlebug feeding).

  3. Evaluate the Relationship Between Class 1 Integrons and Drug Resistance Genes in Clinical Isolates of Pseudomonas aeruginosa

    PubMed Central

    Hosseini, Seyed Mohammad Javad; Naeini, Niloofar Shoaee; Khaledi, Azad; Daymad, Seyede Fatemeh; Esmaeili, Davoud

    2016-01-01

    Background: The prevalence of resistant Pseudomonas aeruginosa isolates is increasing and it is considered as one of the major public health concerns in the world. The association between integrons and drug resistance has been proven and evidences suggest that integrons are coding and responsible for dissemination of antibiotic resistance among P. aeruginosa isolates. Objective: This study is aimed to evaluate the relationship between class 1 integrons and drug resistance genes in clinical isolates of P. aeruginosa from burn patients. Methods: 100 isolates of P. aeruginosa were collected from burn patients hospitalized in the skin ward of Shahid Motahari hospital and susceptibility testing was performed by disk diffusion method (Kirby-Bauer). Then DNA was extracted and PCR technique was performed for the detection of class 1 integrons and drug resistance genes. Then data was analyzed using SPSS software. Results: The most effective antibiotic was polymyxin B with sensitivity 100%, and the most resistance was observed to the ciprofloxacin (93%) and amikacin (67%), respectively. The maximum and lowest frequencies of drug resistance genes belonged to the aac (6 ') - 1, VEB-1 with prevalence rate 93% and 10%, respectively. The statistical Chi-square test did not find any significant correlation between class 1 integrons and drug resistance genes (p˃ 0.05). Conclusion: Although no significant correlation between class 1 integrons and drug resistance was observed, but the resistance rate to antibiotics tested among P. aeruginosa isolates was high. So, surveillance, optimization and strict consideration of antimicrobial use and control of infection are necessary. PMID:28077975

  4. Evaluating Current and Future Rangeland Health in the Great Basin Ecoregion Using NASA Earth Observing Systems

    NASA Astrophysics Data System (ADS)

    Essoudry, E.; Wilson, K.; Ely, J.; Patadia, N.; Zajic, B.; Torres-Perez, J. L.; Schmidt, C.

    2014-12-01

    The Great Basin ecoregion in the western United States represents one of the last large expanses of wild lands in the nation and is currently facing significant challenges due to human impacts, drought, invasive species encroachment such as cheatgrass, and climate change. Rangelands in the Great Basin are of important ecological and economic significance for the United States; however, 40% of public rangelands fail to meet required health standards set by the Bureau of Land Management (BLM). This project provided a set of assessment tools for researchers and land managers that integrate remotely-sensed and in situ datasets to quantify and mitigate threats to public lands in the Great Basin ecoregion. The study area, which accounts for 20% of the total Great Basin ecoregion, was analyzed using 30 m resolution data from Landsat 8. Present conditions were evaluated from vegetation indices, landscape features, hydrological processes, and atmospheric conditions derived from the remotely-sensed data and validated with available in situ ground survey data, provided by the BLM. Rangeland health metrics were developed and landscape change drivers were identified. Subsequently, projected climate conditions derived from the Coupled Model Intercomparison Project (CMIP5) were used to forecast the impact of changing climatic conditions within the study area according to the RCP4.5 and RCP8.5 projections. These forecasted conditions were used in the Maximum Entropy Model (MaxEnt) to predict areas at risk for rangeland degradation on 30 year intervals for 2040, 2070, and 2100. Finally, vegetation health risk maps were provided to the project partners to aid in future land management decisions in the Great Basin ecoregion. These tools provide a low cost solution to assess landscape conditions, provide partners with a metric to identify potential problematic areas, and mitigate serious threats to the ecosystems.

  5. On the current state of the Hydrologic Evaluation of Landfill Performance (HELP) model.

    PubMed

    Berger, Klaus U

    2015-04-01

    The Hydrologic Evaluation of Landfill Performance (HELP) model is the most widely applied model to calculate the water balance of cover and bottom liner systems for landfills. The paper summarizes the 30 year history of the model from HELP version 1 to HELP 3.95 D and includes references to the three current and simultaneously available versions (HELP 3.07, Visual HELP 2.2, and HELP 3.95 D). A sufficient validation is an essential precondition for the use of any model in planning. The paper summarizes validation approaches for HELP 3 focused on cover systems in the literature. Furthermore, measurement results are compared to simulation results of HELP 3.95 D for (1) a test field with a compacted clay liner in the final cover of the landfill Hamburg-Georgswerder from 1988 to 1995 and (2) a test field with a 2.3m thick so-called water balance layer on the landfill Deetz near Berlin from 2004 to 2011. On the Georgswerder site actual evapotranspiration was well reproduced by HELP on the yearly average as well as in the seasonal course if precipitation data with 10% systematic measurement errors were used. However, the increase of liner leakage due to the deterioration of the clayey soil liner was not considered by the model. On the landfill Deetz HELP overestimated largely the percolation through the water balance layer resulting from an extremely wet summer due to an underestimation of the water storage in the layer and presumably also due to an underestimation of the actual evapotranspiration. Finally based on validation results and requests from the practice, plans for improving the model to a future version HELP 4 D are described.

  6. Current approaches and issues in non-clinical evaluation of abuse and dependence.

    PubMed

    Moser, Paul; Wolinsky, Toni; Castagné, Vincent; Duxon, Mark

    2011-01-01

    Preclinical assessment of drug abuse and dependence has been the subject of several recent regulatory guidelines. Both the European and US authorities recommend a tiered approach and are generally aligned on the methods which should be used. The first tier simply compares the pharmacology of the novel substance to known drugs of abuse. The second tier aims to identify abuse and dependence liability more directly. The most direct approach to assessing reinforcing properties is the i.v. self-administration procedure. Unfortunately there is no standardized procedure for evaluating substances with differing potencies, reinforcement properties or pharmacokinetics (PK). Indeed, the choice of training substance, species and procedural parameters can radically affect the outcome. Apart from the lower cost of the rat, the primate presents several advantages for self-administration studies (potentially greater similarity to humans in behavioral effects, active doses and PK). Although it does not measure abuse liability directly, drug discrimination is a powerful method for assessing the similarity of a test substance to a known drug of abuse. In this procedure an animal uses the interoceptive effects of the substance as the discriminative stimulus to determine which of two responses to make. For certain classes of substance, such as hallucinogens acting via the 5-HT(2A) receptor, discrimination is the only procedure currently able to identify them. Drug dependence is assessed by the occurrence of withdrawal effects on drug discontinuation. Although conceptually simple, many factors (duration and frequency of drug treatment, dose/exposure levels, duration of observation after discontinuation) can complicate interpretation. Telemetry may represent a novel approach which allows continuous observation of somatic and behavioral parameters during drug withdrawal thereby increasing sensitivity. Presently available tools can identify essentially all substances known to cause abuse

  7. Evaluation of the Current Opioid Misuse Measure among substance use disorder treatment patients

    PubMed Central

    Ashrafioun, Lisham; Bohnert, Amy S.B.; Jannausch, Mary; Ilgen, Mark A.

    2015-01-01

    The Current Opioid Misuse Measure (COMM) has demonstrated promising psychometric properties among pain clinic and primary care patients. Given the high prevalence of the nonmedical use of prescription opioids among substance use disorder patients, the COMM may also be useful in substance use disorder treatment settings. The purpose of this study was to assess the factor structure and validity of the COMM in a sample of substance use disorder patients. Participants (n = 351) were recruited from a large residential substance use disorder treatment center and completed the COMM and several questionnaires assessing various substance use and health functioning characteristics. Factor analyses yield a two-factor solution; however, each of the items in the second factor cross-loaded onto the first factor and just one factor was retained. To provide support for this new 11-item COMM, we found that higher scores on this COMM were associated with greater drug use severity, greater endorsement of positive, negative, and pain relief outcome expectancies related to opioid use, increased pain intensity, and decreased physical and mental health functioning. These findings provide initial support for the psychometric properties of this version of the COMM adapted for substance use disorder treatment settings. Given its promising psychometric properties, the 11 items of the COMM to evaluate the nonmedical use of prescription opioids has potential utility among substance use disorder patients. The COMM could be used to examine nonmedical use over the course of treatment and to aid treatment planning. It could also be used in research as an outcome measure. PMID:25800105

  8. Evaluation of current and projected Antarctic precipitation in CMIP5 models

    NASA Astrophysics Data System (ADS)

    Palerme, Cyril; Genthon, Christophe; Claud, Chantal; Kay, Jennifer E.; Wood, Norman B.; L'Ecuyer, Tristan

    2017-01-01

    On average, the models in the Fifth Climate Model Intercomparison Project archive predict an increase in Antarctic precipitation from 5.5 to 24.5 % between 1986-2005 and 2080-2099, depending on greenhouse gas emissions scenarios. This translates into a moderation of future sea level rise ranging from -19 to -71 mm between 2006 and 2099. However, comparison with CloudSat and ERA-Interim data show that almost all the models overestimate current Antarctic precipitation, some by more than 100 %. If only the models that agree with CloudSat data within 20 % of error are considered, larger precipitation changes (from 7.4 to 29.3 %) and impact on sea level (from -25 to -85 mm) are predicted. A common practice of averaging all models to evaluate climate projections thus leads to a significant underestimation of the contribution of Antarctic precipitation to future sea level. Models simulate, on average, a 7.4 %/°C precipitation change with surface temperature warming. The models in better agreement with CloudSat observations for Antarctic snowfall predict, on average, larger temperature and Antarctic sea ice cover changes, which could explain the larger changes in Antarctic precipitation simulated by these models. The agreement between the models, CloudSat data and ERA-Interim is generally less in the interior of Antarctica than at the peripheries, but the interior is also where climate change will induce the smallest absolute change in precipitation. About three-quarters of the impact on sea level will result from precipitation change over the half most peripheral and lowest elevation part of the surface of Antarctica.

  9. Field evaluation of shallow-water acoustic doppler current profiler discharge measurements

    USGS Publications Warehouse

    Rehmel, M.S.

    2007-01-01

    In 2004, the U.S. Geological Survey (USGS) Office of Surface Water staff and USGS Water Science employees began testing the StreamPro, an acoustic Doppler current profiler (ADCP) for shallow-water discharge measurements. Teledyne RD Instruments introduced the StreamPro in December of 2003. The StreamPro is designed to make a "moving boat" discharge measurement in streams with depths between 0.15 and 2 m. If the StreamPro works reliably in these conditions, it will allow for use of ADCPs in a greater number of streams than previously possible. Evaluation sites were chosen to test the StreamPro over a range of conditions. Simultaneous discharge measurements with mechanical and other acoustic meters, along with stable rating curves at established USGS streamflow-gaging stations, were used for comparisons. The StreamPro measurements ranged in mean velocity from 0.076 to 1.04 m/s and in discharge from 0.083 m 3/s to 43.4 m 3/s. Tests indicate that discharges measured with the StreamPro compare favorably to the discharges measured with the other meters when the mean channel velocity is greater than 0.25 m/s. When the mean channel velocity is less than 0.25 m/s, the StreamPro discharge measurements for individual transects have greater variability than those StreamPro measurements where the mean channel velocity is greater than 0.25 m/s. Despite this greater variation in individual transects, there is no indication that the StreamPro measured discharges (the mean discharge for all transects) are biased, provided that enough transects are used to determine the mean discharge. ?? 2007 ASCE.

  10. Analysis of the variation in use-dependent inactivation of high-threshold tetrodotoxin-resistant sodium currents recorded from rat sensory neurons.

    PubMed

    Tripathi, P K; Trujillo, L; Cardenas, C A; Cardenas, C G; de Armendi, A J; Scroggs, R S

    2006-12-28

    This study addressed variation in the use-dependent inactivation (UDI) of high-threshold tetrodotoxin-resistant Na+ currents (TTX-R currents) and action potential firing behavior among acutely isolated rat dorsal root ganglion (DRG) cells. UDI was quantified as the percent decrease in current amplitude caused by increasing the current activation rate from 0.1-1.0 Hz for 20 s. TTX-R current UDI varied from 6% to 66% among 122 DRG cells examined, suggesting the existence of two or more levels of UDI. The voltage-dependency of the TTX-R currents was consistent with Na(V)1.8, regardless of UDI. However, TTX-R currents with more UDI had a more negative voltage-dependency of inactivation, a greater tendency to enter slow inactivation, and a slower recovery rate from slow inactivation, compared with those with less UDI. TTX-R currents with more UDI ran down faster than those with less UDI. However, UDI itself changed little over time, regardless of the initial UDI level observed in a particular DRG cell. Together, these two observations suggest that individual DRG cells did not express mixtures of TTX-R channels that varied regarding UDI. TTX-R current UDI was correlated with expression of a low-threshold A-current and whole-cell capacitance, suggesting that it varied among different nociceptor types. Whole-cell inward currents (WCI-currents), recorded without channel blockers, also exhibited UDI. WCI-current UDI varied similarly to TTX-R current UDI in magnitude, and relative to whole-cell capacitance and A-current expression, suggesting that the WCI-currents were carried predominantly by TTX-R channels. DRG cells with more WCI-current UDI exhibited a greater decrease in action potential amplitude and number, and a greater increase in action potential threshold over seven ramp depolarizations, compared with DRG cells with less WCI-current UDI. Variation in UDI of Na(V)1.8 channels expressed by different nociceptor types could contribute to shaping their individual firing

  11. Making It Your Own: Writing Fellows Re-Evaluate Faculty "Resistance"

    ERIC Educational Resources Information Center

    Halasz, Judith; Brinckner, Maria

    2006-01-01

    Faculty resistance to Writing Across the Curriculum (WAC) is an issue that has been recognized by WAC program directors and practitioners for decades, yet it remains unresolved. Perhaps the problem is not resistance per se, but how we interpret and react to it. Faculty resistance is typically viewed as an impediment to the pedagogical change WAC…

  12. Evaluation of aerodynamic and rolling resistances in mountain-bike field conditions.

    PubMed

    Bertucci, William M; Rogier, Simon; Reiser, Raoul F

    2013-01-01

    Aerodynamic and rolling resistances are the two major resistances that affect road cyclists on level ground. Because of reduced speeds and markedly different tyre-ground interactions, rolling resistance could be more influential in mountain biking than road cycling. The aims of this study were to quantify 1) aerodynamic resistance of mountain-bike cyclists in the seated position and 2) rolling resistances of two types of mountain-bike tyre (smooth and knobby) in three field surfaces (road, sand and grass) with two pressure inflations (200 and 400 kPa). Mountain-bike cyclists have an effective frontal area (product of projected frontal area and drag coefficient) of 0.357 ± 0.023 m², with the mean aerodynamic resistance representing 8-35% of the total resistance to cyclists' motion depending on the magnitude of the rolling resistance. The smooth tyre had 21 ± 15% less rolling resistance than the knobby tyre. Field surface and inflation pressure also affected rolling resistance. These results indicate that aerodynamic resistance influences mountain-biking performance, even with lower speeds than road cycling. Rolling resistance is increased in mountain biking by factors such as tyre type, surface condition and inflation pressure that may also alter performance.

  13. Evaluation of data quality in a laboratory-based surveillance of M. tuberculosis drug resistance and impact on the prevalence of resistance: France, 2004

    PubMed Central

    KHUÊ, P. M.; MALLET, A.; VEZIRIS, N.; JARLIER, V.; ROBERT, J.

    2008-01-01

    SUMMARY In France, surveillance of anti-tuberculosis drug resistance is performed by the Azay-Mycobacteria network, representing 30% of all culture-positive cases. We sought to validate administrative and clinical data gathered by the network in 2004 and to produce corrected resistance rates accounting for the observed misclassification. We reviewed a 10% sample of patients' records diagnosed in 2004 and measured the agreement between controlled data and data collected by the network by using the kappa (κ) statistic. A re-sampling bootstrap-based method was used to investigate the impact of bias found on resistance rates. Most of data collected by the network, such as demographic data, and country of birth had an excellent agreement (κ>0·8) with controlled data. The concordance was good (κ>0·6) for HIV status and tuberculosis site. The only variable slightly discordant with controlled data was prior history of treatment (κ=0·52). However, after correcting crude resistance rates for the observed misclassification, all estimated rates were within confidence intervals based on reported rates. This validation study is in favour of a good quality of data produced by the network, even though corrected rates are slightly different from observed rates. Therefore, data collected through the network may be used for policy making and tuberculosis programme evaluation. However, improvement in data collection regarding prior history of treatment should be considered. PMID:18028573

  14. Current epidemiology and antimicrobial resistance data for bacterial bloodstream infections in patients with hematologic malignancies: an Italian multicentre prospective survey.

    PubMed

    Trecarichi, E M; Pagano, L; Candoni, A; Pastore, D; Cattaneo, C; Fanci, R; Nosari, A; Caira, M; Spadea, A; Busca, A; Vianelli, N; Tumbarello, M

    2015-04-01

    A prospective cohort study was conducted in nine hematology wards at tertiary care centres or at university hospitals located throughout Italy from January 2009 to December 2012. All of the cases of bacterial bloodstream infection (BBSI) occurring in adult patients with hematologic malignancies were included. A total of 668 bacterial isolates were recovered in 575 BBSI episodes. Overall, the susceptibility rates of Gram-negative bacteria were 59.1% to ceftazidime, 20.1% to ciprofloxacin, 79.1% to meropenem, 85.2% to amikacin, 69.2% to gentamicin and 69.8% to piperacillin/tazobactam. Resistance to third-generation cephalosporins was found in 98/265 (36.9%) of Enterobacteriaceae isolates. Among Klebsiella pneumoniae strains, 15/43 (34.9%) were resistant to carbapenems. Of 66 Pseudomonas aeruginosa isolates, 46 (69.7%) were multidrug resistant. Overall, the susceptibility rates of Gram-positive bacteria were 97.4% to vancomycin and 94.2% to teicoplanin. Among the monomicrobial cases of BBSI, the 21-day mortality rate was significantly higher for those caused by Gram-negative bacteria compared to those caused by Gram-positive bacteria (47/278, 16.9% vs. 12/212, 5.6%; p < 0.001). Among Gram-negative bacteria, the mortality rate was significantly higher for BBSI caused by K. pneumoniae, P. aeruginosa, and Acinetobacter baumannii. Our results confirm the recently reported shift of prevalence from Gram-positive to Gram-negative bacteria as causative agents of BBSIs among patients with hematologic malignancies and highlight a worrisome increasing frequency in antimicrobial resistance among Gram-negative bacteria.

  15. Computational study of the resistance shown by the Subtype B / HIV-1 Protease to currently known inhibitors †

    PubMed Central

    Genoni, Alessandro; Morra, Giulia; Merz, Kenneth M.; Colombo, Giorgio

    2010-01-01

    Human Immunodeficiency Virus type 1 Protease (HIV-1 PR) is an essential enzyme in the HIV-1 life cycle. As such, this protein represents a major drug target in AIDS therapy, but emerging resistance to anti-retroviral inhibitor cocktails, due to high viral mutation rates, represents a significant challenge in AIDS treatment. Many mutations are not located within the active site or binding pocket, nor they do significantly modify the 3D structural organization of the enzyme; hence, the mechanism(s) by which they alter inhibitor affinity for the Protease remains uncertain. In this article, we present an all-atom computational analysis of the dynamic residue-residue coordination between the active site residues and the rest of the protein and of the energetic properties of different HIV-1 PR complexes. We analyze both the wild type form and mutated forms that induce drug resistance. In particular, the results show differences between the wild type and the mutants in their mechanism of dynamic coordination, in the signal propagation between the active site residues and the rest of the protein and in the energy-networks responsible for the stabilization of the bound inhibitor conformation. Finally, we propose a dynamic and energetic explanation for HIV-1 Protease drug resistance and, through this model, we identify a possible new site that could be helpful in the design of a new family of HIV-1 PR allosteric inhibitors. PMID:20415450

  16. Multiple pulse-heating experiments with different current to determine total emissivity, heat capacity, and electrical resistivity of electrically conductive materials at high temperatures.

    PubMed

    Watanabe, Hiromichi; Yamashita, Yuichiro

    2012-01-01

    A modified pulse-heating method is proposed to improve the accuracy of measurement of the hemispherical total emissivity, specific heat capacity, and electrical resistivity of electrically conductive materials at high temperatures. The proposed method is based on the analysis of a series of rapid resistive self-heating experiments on a sample heated at different temperature rates. The method is used to measure the three properties of the IG-110 grade of isotropic graphite at temperatures from 850 to 1800 K. The problem of the extrinsic heating-rate effect, which reduces the accuracy of the measurements, is successfully mitigated by compensating for the generally neglected experimental error associated with the electrical measurands (current and voltage). The results obtained by the proposed method can be validated by the linearity of measured quantities used in the property determinations. The results are in reasonably good agreement with previously published data, which demonstrate the suitability of the proposed method, in particular, to the resistivity and total emissivity measurements. An interesting result is the existence of a minimum in the emissivity of the isotropic graphite at around 1120 K, consistent with the electrical resistivity results.

  17. Final report on RMO comparison SIM.EM-S10: High value resistance comparison with two-terminal cryogenic current comparators

    NASA Astrophysics Data System (ADS)

    Bierzychudek, Marcos E.; Elmquist, Randolph; Hernández, Felipe

    2014-01-01

    This work presents a supplementary comparison of high value resistance standards performed during 2012 and January 2013, following the guidelines presented in a document about measurement comparisons in the CIPM MRA. The purpose of this task was to compare the high resistance cryogenic current comparator scaling of the participating institutes: National Institute of Standards and Technology, USA (NIST), Centro Nacional de Metrología, Mexico (CENAM) and Instituto Nacional de Tecnología Industrial, Argentina (INTI), all of which are members of the Sistema Interamericano de Metrología (SIM) Regional Metrology Organization. All the measurements of this comparison were performed with two-terminal cryogenic current comparators (CCC). Degrees of equivalence of the participating institutes relative to the comparison reference values are given in the report for the measured resistance values. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/. The final report has been peer-reviewed and approved for publication by SIM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).

  18. Finite Element Modeling of the Magnetotelluric Phase Tensor Response to Evaluate Sensitivity to Lateral and Vertical Resistivity Contrasts

    NASA Astrophysics Data System (ADS)

    Hawkes, S.; McClain, J. S.

    2015-12-01

    Phase tensor analysis of magnetotelluric data is a relatively new technique introduced by Caldwell et. al. (2004) and requires substantial research efforts to evaluate the capabilities of the method. We have conducted finite element (FE) modeling using the AC/DC module of Comsol Multiphysics to determine the effect of resistivity structure on the phase tensor response. Measurements are made at eleven frequencies from 10-104 Hz at points on a 5x5 grid above various simple model geometries. Phase tensor plotting methods are adapted from Booker (2013) and involve displaying data graphically as stacks of colored ellipses. This allows for interpretation across the frequency spectrum vertically as well as laterally between stations. Two types of plot are presented for each model, a "ϕmin plot" where the ellipses are colored according to the minimum principle phase and a "delta plot" where the ellipses are colored according to the difference between the principle phases (ϕmax - ϕmin), which provides a quantification of the phase anisotropy. Results suggest that the principle phases ϕmin and ϕmax are sensitive to vertical resistivity contrasts but not lateral resistivity contrasts. Conversely, delta plots reveal sensitivity to lateral resistivity contrasts but not vertical resistivity contrasts. A clear distance relationship is observed with proximity to the boundary controlling the frequency range that senses a lateral resistivity contrast. Rotation of the phase tensor ellipses and increased skew values occur in the presence of resistivity contrasts that strike nonparallel to the source field, with the effect increasing towards lower frequencies. The total phase tensor response is confirmed to be sensitive to both vertical and lateral resistivity contrasts and can be used effectively to interpret subsurface resistivity structure.

  19. Experiments of the selection of a method evaluating the fire resistance of some materials based on macromolecular compounds

    NASA Technical Reports Server (NTRS)

    Stoica, Steln; Sebe, Mircea Octavian

    1987-01-01

    A comparative experimental study on the application of various tests for the evaluation of the fire-resistant properties of plastic materials is presented. On the basis of the results obtained conclusions are drawn on the advantages and disadvantages of the methods used, and a preferred test method is picked, i.e., the introduction of fire retardant materials into the polymers.

  20. Evaluation of triticale accessions for resistance to wheat bacterial leaf streak caused by Xanthomonas translucens pv. undulosa

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The bacterium Xanthomonas translucens pv. undulosa (Xtu) causes bacterial leaf streak (BLS) on wheat and other small grains. Several triticale accessions were reported to possess high levels of resistance to wheat Xtu strains. In this study, we evaluated a worldwide collection of 502 triticale acces...