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Sample records for improved fixed switching

  1. Improved Two-Phase Switching Regulator

    NASA Technical Reports Server (NTRS)

    Rippel, W. E.

    1984-01-01

    Coupled-inductor polyphase regulator has better efficiency and lower inductor losses. Improved two-phase switching regulator employs negative coupling between inductors to achieve better power-to-weight ratio while reducing peak switching currents and inductor losses. Improvement of about 35 percent using new technique.

  2. Efficacy of fixed filtration for rapid kVp-switching dual energy x-ray systems

    SciTech Connect

    Yao, Yuan; Wang, Adam S.; Pelc, Norbert J.

    2014-03-15

    Purpose: Dose efficiency of dual kVp imaging can be improved if the two beams are filtered to remove photons in the common part of their spectra, thereby increasing spectral separation. While there are a number of advantages to rapid kVp-switching for dual energy, it may not be feasible to have two different filters for the two spectra. Therefore, the authors are interested in whether a fixed added filter can improve the dose efficiency of kVp-switching dual energy x-ray systems. Methods: The authors hypothesized that a K-edge filter would provide the energy selectivity needed to remove overlap of the spectra and hence increase the precision of material separation at constant dose. Preliminary simulations were done using calcium and water basis materials and 80 and 140 kVp x-ray spectra. Precision of the decomposition was evaluated based on the propagation of the Poisson noise through the decomposition function. Considering availability and cost, the authors chose a commercial Gd{sub 2}O{sub 2}S screen as the filter for their experimental validation. Experiments were conducted on a table-top system using a phantom with various thicknesses of acrylic and copper and 70 and 125 kVp x-ray spectra. The authors kept the phantom exposure roughly constant with and without filtration by adjusting the tube current. The filtered and unfiltered raw data of both low and high energy were decomposed into basis material and the variance of the decomposition for each thickness pair was calculated. To evaluate the filtration performance, the authors measured the ratio of material decomposition variance with and without filtration. Results: Simulation results show that the ideal filter material depends on the object composition and thickness, and ranges across the lanthanide series, with higher atomic number filters being preferred for more attenuating objects. Variance reduction increases with filter thickness, and substantial reductions (40%) can be achieved with a 2× loss in

  3. Improved techniques for switching power amplifiers

    SciTech Connect

    Flinder, F.M.; Wolfs, P.J.; Kwong, K.C.

    1993-10-01

    The control system design of a dc to 10 kHz bandwidth 45 kVA current sourced power amplifier suitable for geophysical exploration applications is presented. A five-level modulation scheme has been implemented using a modified bridge topology with only four switches. This scheme give as an order of magnitude improvement in switching ripple and control performance over two-level modulation. Using this system, a 50 kHz switch frequency allows a 20 kHz, {minus}3dB bandwidth to be easily achieved. Simulation as well as tenth scale model test results are presented. The current output waveform reproduction is of high quality over the rated dc to 10 kHz frequency range. The THD is 0.3% at 1 kHz.

  4. Improved heat switch for gas sorption compressor

    NASA Technical Reports Server (NTRS)

    Chan, C. K.

    1985-01-01

    Thermal conductivities of the charcoal bed and the copper matrix for the gas adsorption compressor were measured by the concentric-cylinder method. The presence of the copper matrix in the charcoal bed enhanced the bed conductance by at least an order of magnitude. Thermal capacities of the adsorbent cell and the heat leaks to two compressor designs were measured by the transient method. The new gas adsorption compressor had a heat switch that could transfer eight times more heat than the previous one. The cycle time for the new prototype compressor is also improved by a factor of eight to within the minute range.

  5. Group consensus control for heterogeneous multi-agent systems with fixed and switching topologies

    NASA Astrophysics Data System (ADS)

    Wen, Guoguang; Huang, Jun; Wang, Chunyan; Chen, Zhi; Peng, Zhaoxia

    2016-02-01

    In this paper, the group consensus problems of heterogeneous multi-agent systems with fixed and switching topologies are investigated. First, a class of distributed group consensus protocol is proposed for achieving the group consensus of heterogeneous multi-agent systems by using the neighbours' information. Then, some corresponding sufficient conditions are obtained to guarantee the achievement of group consensus. Rigorous proofs are given by using graph theory, matrix theory and Lyapunov theory. Finally, numerical simulations are also given to verify the theoretical analysis.

  6. An improved, explosively actuated closing switch for pulsed power applications

    SciTech Connect

    Parker, J.V.; Bartsch, R.R.; Cochrane, J.C.; Marsh, S.P.

    1993-01-01

    An improved, explosively actuated closing switch has been developed for the Pegasus II capacitor bank. The new switch design uses an annular metal jet as the switch contact. It has lower resistance and inductance at early time than the original design. A parallel array of 24 switches on Pegasus II has a resistance of less than 10 [mu][Omega] after 300 ns. Measured time behaviors include an intrinsic jitter of 50 ns and a switching delay that depends inversely on the applied voltage.

  7. An improved, explosively actuated closing switch for pulsed power applications

    SciTech Connect

    Parker, J.V.; Bartsch, R.R.; Cochrane, J.C.; Marsh, S.P.

    1993-07-01

    An improved, explosively actuated closing switch has been developed for the Pegasus II capacitor bank. The new switch design uses an annular metal jet as the switch contact. It has lower resistance and inductance at early time than the original design. A parallel array of 24 switches on Pegasus II has a resistance of less than 10 {mu}{Omega} after 300 ns. Measured time behaviors include an intrinsic jitter of 50 ns and a switching delay that depends inversely on the applied voltage.

  8. Interactions Between Autotrophic and Heterotrophic Strains Improve CO₂ Fixing Efficiency of Non-photosynthetic Microbial Communities.

    PubMed

    Hu, Jiajun; Wang, Lei; Zhang, Shiping; Xi, Xuefei; Le, Yiquan; Fu, Xiaohua; Tsang, Yiufai; Gao, Mintian

    2015-07-01

    Five autotrophic strains isolated from non-photosynthetic microbial communities (NPMCs), which were screened from oceans with high CO2 fixing capability, were identified as Ochrobactrum sp. WH-2, Stenotrophomonas sp. WH-11, Ochrobactrum sp. WH-13, Castellaniella sp. WH-14, and Sinomicrobium oceani WH-15. The CO2 fixation pathways of all these strains were Calvin-Benson-Bassham pathway. These strains could metabolize multifarious organic compounds, which allowed switching them to autotrophic culture after enrichment in heterotrophic culture. The central composite response surface method indicated that these strains possessed many interactive effects, which increased the CO2 fixing efficiency of a combined community composed of these strains by 56 %, when compared with that of the single strain. Furthermore, another combined community composed of these autotrophic strains and NPMC had richer interactive relationships, with CO2 fixing efficiency being 894 % higher than that of the single strain and 148 % higher than the theoretical sum of the CO2 fixing efficiency of each of its microbial components. The interaction between strictly heterotrophic bacteria in NPMC and isolated autotrophic strains played a crucial role in improving the CO2 fixing efficiency, which not only eliminated self-restraint of organic compounds generated during the growth of autotrophic bacteria but also promoted its autotrophic pathway. PMID:25947620

  9. Backbone switch to abacavir/lamivudine fixed-dose combination: implications for antiretroviral therapy optimization.

    PubMed

    Fantauzzi, Alessandra; Floridia, Marco; Falasca, Francesca; Spanedda, Pierpaolo; Turriziani, Ombretta; Vullo, Vincenzo; Mezzaroma, Ivano

    2015-10-01

    Current guidelines recommend treatment optimization in virologically suppressed patients through switching/ simplification strategies to minimize long-term toxicities and improve adherence. The assessment of inflammation/ coagulation profiles may support therapeutic decisions. We undertook a prospective, non-randomized study to evaluate the efficacy and safety of switching to ABC/3TC from ZDV/3TC or TDF/FTC backbones, in 40 HIV-1 infected patients with HIV-RNA levels <37 copies/mL (>24 months). Main endpoints were viral load levels, CD4+ T cells and toxicities after 48 weeks. Serum inflammation/coagulation markers (ESR, CRP, D-dimer and fibrinogen) and pro-inflammatory cytokines (IL-6, TNF-α, adiponectin, resistin) were evaluated. Baseline characteristics were similar in the two arms, with significantly lower values of e-GFR in patients on TDF/FTC. Markers of inflammation/ coagulation and cytokine profile were also similar, except for higher values of resistin in patients on TDF/ FTC. During follow up, CD4+ T cells increased and viral load remained undetectable in both groups. Patient from ZDV/3TC had significantly greater changes in total cholesterol and serum creatinine. Markers of inflammation/ coagulation remained unchanged. Adiponectin significantly increased in patients from ZDV/3TC. Switching to ABC/3TC was effective and safe. Inflammatory markers remained low in both groups. Some changes in metabolic, kidney and cytokine profiles were apparently specific for baseline cART treatment. PMID:26485011

  10. Bearingless Switched-Reluctance Motor Improved

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.

    2004-01-01

    The Morrison rotor, named after its inventor, is a hybrid rotor for use in a switched reluctance electric motor. The motor is characterized as bearingless in the sense that it does not rely on conventional mechanical bearings: instead, it functions as both a magnetic bearing and a motor. Bearingless switched-reluctance motors are attractive for use in situations in which large variations in temperatures and/or other extreme conditions preclude the use of conventional electric motors and mechanical bearings. In the Morrison motor, as in prior bearingless switched-reluctance motors, a multipole rotor is simultaneously levitated and rotated. In the prior motors, simultaneous levitation and rotation are achieved by means of two kinds of stator windings: (1) main motor windings and (2) windings that exert levitating forces on a multipole rotor. The multipole geometry is suboptimum for levitation because it presents a discontinuous surface to the stator pole faces, thereby degrading the vibration suppression capability of the magnetic bearing. The Morrison rotor simplifies the stator design in that it contains only one type of winding. The rotor is a hybrid that includes both (1) a circular lamination stack for levitation and (2) a multipole lamination stack for rotation. Simultaneous levitation and rotation at 6000 rpm were achieved with a prototype that included six rotor poles and eight stator poles. During normal operation, two of the four pairs of opposing stator poles (each pair at right angles to the other pair) levitate the rotor. The remaining two pairs of stator poles exert torque on the six-pole rotor lamination stack to produce rotation. The relative length of the circular and multipole lamination stacks on the rotor can be chosen to tailor the performance of the motor for a specific application. For a given overall length, increasing the length of the multipole stack relative to the circular stack results in an increase in torque relative to the levitation

  11. Improved Bearingless Switched-Reluctance Motor

    NASA Technical Reports Server (NTRS)

    Morrison, Carlos R.

    2003-01-01

    The Morrison rotor, named after its inventor, is a hybrid rotor for use in a bearingless switched-reluctance electric motor. The motor is characterized as bearingless in the sense that it does not rely on conventional mechanical bearings: instead, it functions as both a magnetic bearing and a motor. Bearingless switched-reluctance motors are attractive for use in situations in which large variations in temperatures and/or other extreme conditions preclude the use of conventional electric motors and mechanical bearings. In the Morrison motor, as in a prior bearingless switched-reluctance motor, a multipole rotor is simultaneously levitated and rotated. In the prior motor, simultaneous levitation and rotation are achieved by means of two kinds of stator windings: (1) main motor windings and (2) windings that exert levitating forces on a multipole rotor. The multipole geometry is suboptimum for levitation in that it presents a discontinuous surface to the stator pole faces, thereby degrading the vibration-suppression capability of the magnetic bearing. The Morrison rotor simplifies the stator design in that the stator contains only one type of winding. The rotor is a hybrid that includes both (1) a circular lamination stack for levitation and (2) a multipole lamination stack for rotation. A prototype includes six rotor poles and eight stator poles (see figure). During normal operation, two of the four pairs of opposing stator poles (each pair at right angles to the other pair) levitate the rotor. The remaining two pairs of stator poles exert torque on the six-pole rotor lamination stack to produce rotation. The relative lengths of the circular and multipole lamination stacks on the rotor can be chosen to tailor the performance of the motor for a specific application. For a given overall length, increasing the length of the multipole stack relative to the circular stack results in an increase in torque relative to levitation load capacity and stiffness, and vice versa.

  12. Fixed bimonthly aflibercept in naïve and switched neovascular age-related macular degeneration patients: one year outcomes

    PubMed Central

    Warwick, Alasdair N; Leaver, Hannah H; Lotery, Andrew J; Goverdhan, Srini V

    2016-01-01

    AIM To determine real life clinical outcomes in poorly responsive and treatment-naïve neovascular age related macular degeneration (nvAMD) patients using bimonthly fixed dosing aflibercept regimen. METHODS This was a retrospective study of 165 eyes with nvAMD started on aflibercept at Southampton Eye Unit between June 2013 and June 2014. Patients were either switched from pro re nata (PRN) ranibizumab/bevacizumab due to poor response (107 eyes), or treatment-naïve (58 eyes). Patients initially received 3-monthly intravitreal aflibercept injections followed by 2-monthly fixed doses. Clinic visits were scheduled at month 0, 4, 10 and 12. Mean change in best-corrected visual acuity (BCVA) and central retinal thickness (CRT) from baseline were assessed using the Wilcoxon signed-rank test. The proportion of patients maintaining BCVA (<15 letters loss) at 12mo was also evaluated. RESULTS Mean BCVA change at month 12 was +3.29 and +4.67 letters in the switched and naïve aflibercept groups respectively (P<0.01). BCVA was maintained in 95.3% of switched and 96.6% of naïve patients. CRT at month 12 showed a decrease of -6.16 µm in the switched group and -35.36 µm in the naïve group (P<0.01). Patients previously treated with ranibizumab/bevacizumab had on average received 7.4 ranibizumab/bevacizumab injections over 12.6mo, attending 10 clinic visits. The fixed dosing aflibercept regimen required an average of 7.1 injections (naïve group), 7.5 injections (switched group) and 4 clinic visits per year. CONCLUSION Fixed bimonthly aflibercept is effective in both treatment-naïve and poorly responsive nvAMD patients. Adopting a fixed dosing regimen can reduce patient burden without compromising on outcomes. PMID:27588271

  13. Understanding and improving longevity in RF MEMS capacitive switches

    NASA Astrophysics Data System (ADS)

    Goldsmith, Chuck; Forehand, David; Scarbrough, Derek; Peng, Zheng; Palego, Cris; Hwang, James; Clevenger, Jason

    2008-02-01

    This paper discusses issues relating to the reliability and methods for employing high-cycle life testing in capacitive RF MEMS switches. In order to investigate dielectric charging, transient current spectroscopy is used to characterize and model the ingress and egress of charges within the switch insulating layer providing an efficient, powerful tool to investigate various insulating materials without constructing actual MEMS switches. Additionally, an in-situ monitoring scheme has been developed to observe the dynamic evolution of switch characteristics during life testing. As an alternative to high-cycle life testing, which may require days or weeks of testing, a method for performing accelerated life tests is presented. Various methods for mitigating dielectric charging are presented including: reduced operating voltage, reduced dielectric area, and improved control waveforms. Charging models, accelerated life test results, and high-cycle life test results for state-of-the-art capacitive RF MEMS switches aid in the better understanding of MEMS switch reliability providing direction for improving materials and mechanical designs to increase the operation lifetime of MEMS capacitive switches.

  14. Improving the fatigue resistance of diarylethene switches.

    PubMed

    Herder, Martin; Schmidt, Bernd M; Grubert, Lutz; Pätzel, Michael; Schwarz, Jutta; Hecht, Stefan

    2015-02-25

    When applying photochromic switches as functional units in light-responsive materials or devices, an often disregarded yet crucial property is their resistance to fatigue during photoisomerization. In the large family of diarylethene photoswitches, formation of an annulated isomer as a byproduct of the photochromic reaction turns out to prevent the desired high reversibility for many different derivatives. To overcome this general problem, we have synthesized and thoroughly investigated the fatigue behavior of a series of diarylethenes, varying the nature of the hetaryl moieties, the bridging units, and the substituents. By analysis of photokinetic data, a quantification of the tendency for byproduct formation in terms of quantum yields could be achieved, and a strong dependency on the electronic properties of the substituents was observed. In particular, substitution with 3,5-bis(trifluoromethyl)phenyl or 3,5-bis(pentafluorosulfanyl)phenyl groups strongly suppresses the byproduct formation and opens up a general strategy to construct highly fatigue-resistant diarylethene photochromic systems with a large structural flexibility. PMID:25679768

  15. Switching efficiency improvement in spin torque majority gates

    SciTech Connect

    Nikonov, Dmitri E. Manipatruni, Sasikanth; Young, Ian A.

    2014-05-07

    Spin torque majority gate (STMG) is one of the promising options for beyond complementary metal-oxide-semiconductor logic. Improvement of its performance—switching speed vs. required current—is critical for its competitiveness. In this paper, (a) we identify an optimized layout of the gate comprised of thin magnetic wires with in-plane magnetization; (b) we optimize geometries of perpendicular magnetization spin torque majority gates. Micromagnetic simulations demonstrate an improvement in switching current for in-plane magnetization (with less than 1 ns switching time) from 6 mA in the original scheme to 1.5 mA in the present one. Additionally, failures of switching caused by vortex formation are eliminated and desired output magnetization is achieved. Various geometries of STMG with perpendicular magnetization are explored. The scheme with a straight cross proves to be the most advantageous. It is predicted to operate with the switching current of 50 μA and less than 4 ns switching time.

  16. Switching efficiency improvement in spin torque majority gates

    NASA Astrophysics Data System (ADS)

    Nikonov, Dmitri E.; Manipatruni, Sasikanth; Young, Ian A.

    2014-05-01

    Spin torque majority gate (STMG) is one of the promising options for beyond complementary metal-oxide-semiconductor logic. Improvement of its performance—switching speed vs. required current—is critical for its competitiveness. In this paper, (a) we identify an optimized layout of the gate comprised of thin magnetic wires with in-plane magnetization; (b) we optimize geometries of perpendicular magnetization spin torque majority gates. Micromagnetic simulations demonstrate an improvement in switching current for in-plane magnetization (with less than 1 ns switching time) from 6 mA in the original scheme to 1.5 mA in the present one. Additionally, failures of switching caused by vortex formation are eliminated and desired output magnetization is achieved. Various geometries of STMG with perpendicular magnetization are explored. The scheme with a straight cross proves to be the most advantageous. It is predicted to operate with the switching current of 50 μA and less than 4 ns switching time.

  17. Observer-based consensus in networks of discrete-time switched linear dynamics under a fixed topology

    NASA Astrophysics Data System (ADS)

    Xin, Youming; Li, Yuxia

    2016-09-01

    This paper considers the consensus problem of discrete-time switched linear multi-agent systems under a fixed communication topology. An observer-based protocol with sampled data is proposed for solving such a problem. Assume that the digraph has a directed spanning tree and that all switched subsystem of each agent are stabilisable and detectable. It is shown that the proposed protocol solves the consensus problem when the sampling period is sufficiently small and the average dwell time of the switching signal is sufficiently large. Moreover, to reduce the conservatism, a sufficient condition for consensus is obtained to design the feedback gain matrices and the observer gain matrices by linear matrix inequalities, which guarantee that consensus can be achieved when the sampling period and the average dwell time are in the general case. Finally, the effectiveness of the theoretical results is demonstrated through an example.

  18. Economic impact of switching to fixed-dose combination therapy for Japanese hypertensive patients: a retrospective cost analysis

    PubMed Central

    2013-01-01

    Background The prescription of fixed-dose combinations (FDC) of antihypertensive drugs has increased rapidly since the relaxation of the prescription-term restriction. In this study, we used the opportunity of this policy change in Japan as an instrument to assess the causal impact of switching to FDC on hypertensive treatment costs. Methods Claims data from 64 community pharmacies located in Tokyo were used to identify hypertensive patients under continuous treatment with angiotensin-receptor blockers (ARBs). Patients switching to FDC between December 2010 and April 2011 were compared to patients who did not receive FDC (control group). Changes in annual antihypertensive drug costs were compared using a difference-in-differences approach to adjust for patient characteristics and use of concomitant medication. Subpopulation analyses were also performed, taking into account pre-index treatment patterns and prescribers’ characteristics. Results There were 542 patients who switched to FDC and 9664 patients in the control group. No significant differences were observed between the 2 groups, except for antihypertensive drug use patterns before the policy change and prescribers’ characteristics. The switch to FDC was associated with an annual saving of 10,420 yen (US$112.0) in antihypertensive drug costs. Approximately 20% of the FDC patients, however, switched from ARB alone, and their drug costs increased by 2376 yen (US$25.5). Conclusions For hypertensive patients who required ARB-based combination therapy, switching to FDC drugs had a significant cost-saving effect. However, the policy change of relaxing the prescription-term restriction could encourage aggressive treatment, i.e., switching to a combination therapy from monotherapy, regardless of medical conditions. Further research is required to evaluate the possible negative aspects of FDC drugs. PMID:23552327

  19. On Optimal Control of Non-Autonomous Switched Systems with a Fixed Mode Sequence

    NASA Technical Reports Server (NTRS)

    Kamgarpour, Maryam; Tomlin, Claire

    2012-01-01

    We consider differentiability with respect to the switch times of the value function of an optimal control problem for a non-autonomous switched system. The control variables are the switch times between the modes and the input in each mode. We provide a method to compute the derivative of the cost function given a nominal input. Then, we view the optimal control problem as a parametrized optimization problem in which the switch times are the parameters and the optimization is over the set of feasible inputs of each mode. From this point of view, we provide conditions under which the continuity and differentiability of the optimal value function, that is the cost function optimized over the inputs, can be guaranteed.

  20. Switching from body surface area-based to fixed dosing for the investigational proteasome inhibitor ixazomib: a population pharmacokinetic analysis

    PubMed Central

    Gupta, Neeraj; Zhao, Yuan; Hui, Ai-Min; Esseltine, Dixie-Lee; Venkatakrishnan, Karthik

    2015-01-01

    Aims This population pharmacokinetic analysis of the investigational oral proteasome inhibitor ixazomib assessed the feasibility of switching from body surface area (BSA)-based to fixed dosing, and the impact of baseline covariates on ixazomib pharmacokinetics. Methods Data were pooled from 226 adult patients with multiple myeloma, lymphoma or solid tumours in four phase 1 studies, in which ixazomib dosing (oral/intravenous, once/twice weekly) was based on BSA. Population pharmacokinetic modelling was undertaken using nonmem version 7.2. Results Ixazomib pharmacokinetics were well described by a three compartment model with first order absorption and linear elimination. Ixazomib was absorbed rapidly (Ka 0.5 h−1), with dose- and time-independent pharmacokinetics. Estimated absolute bioavailability and clearance were 60% and 2 l h−1, respectively. Although a small effect of BSA (range 1.3–2.6 m2) was observed on the peripheral volume of distribution (V4), reducing the corresponding inter-individual variability by 12.9%, there was no relationship between BSA and ixazomib clearance (the parameter that dictates total systemic exposure following fixed dosing). Consistently, based on simulations (n = 1000), median AUCs (including interquartile range) were similar after BSA-based (2.23 mg m−2) and fixed (4 mg) oral dosing with no trend in simulated AUC vs. BSA for fixed dosing (P = 0.42). No other covariates, including creatinine clearance (22–213.7 ml min−1) and age (23–86 years), influenced ixazomib pharmacokinetics. Conclusions This analysis supports a switch from BSA-based to fixed dosing, without dose modification for mild/moderate renal impairment or age, in future adult studies of ixazomib, simplifying dosing guidance and clinical development. PMID:25377318

  1. Condition interference in rats performing a choice task with switched variable- and fixed-reward conditions

    PubMed Central

    Funamizu, Akihiro; Ito, Makoto; Doya, Kenji; Kanzaki, Ryohei; Takahashi, Hirokazu

    2015-01-01

    Because humans and animals encounter various situations, the ability to adaptively decide upon responses to any situation is essential. To date, however, decision processes and the underlying neural substrates have been investigated under specific conditions; thus, little is known about how various conditions influence one another in these processes. In this study, we designed a binary choice task with variable- and fixed-reward conditions and investigated neural activities of the prelimbic cortex and dorsomedial striatum in rats. Variable- and fixed-reward conditions induced flexible and inflexible behaviors, respectively; one of the two conditions was randomly assigned in each trial for testing the possibility of condition interference. Rats were successfully conditioned such that they could find the better reward holes of variable-reward-condition and fixed-reward-condition trials. A learning interference model, which updated expected rewards (i.e., values) used in variable-reward-condition trials on the basis of combined experiences of both conditions, better fit choice behaviors than conventional models which updated values in each condition independently. Thus, although rats distinguished the trial condition, they updated values in a condition-interference manner. Our electrophysiological study suggests that this interfering value-updating is mediated by the prelimbic cortex and dorsomedial striatum. First, some prelimbic cortical and striatal neurons represented the action-reward associations irrespective of trial conditions. Second, the striatal neurons kept tracking the values of variable-reward condition even in fixed-reward-condition trials, such that values were possibly interferingly updated even in the fixed-reward condition. PMID:25741231

  2. Effect on intraocular pressure of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in patients with normal-tension glaucoma.

    PubMed

    Igarashi, Ryoko; Togano, Tetsuya; Sakaue, Yuta; Yoshino, Takaiko; Ueda, Jun; Fukuchi, Takeo

    2014-01-01

    Purpose. To evaluate the effect on intraocular pressure (IOP) of switching from latanoprost and travoprost monotherapy to timolol fixed combinations in Japanese patients with normal-tension glaucoma (NTG). Methods. 27 NTG patients (54 eyes) were compared IOP, superficial punctuate keratitis (SPK) scores, and conjunctival injection scores in eyes treated with prostaglandin (PG) or PG analog/beta-blocker (PG/b) fixed-combination 6 months after the change in therapy. Results. The mean baseline intraocular pressure was 17.4 ± 1.59 mmHg in eyes receiving PG therapy only and 17.4 ± 1.69 mmHg in eyes switched to PG/b. Switching to fixed combination therapy from PG monotherapy, the mean IOP was 13.1 ± 1.79 mmHg (P < 0.001)  (-24.71% reduction from baseline) at 6 months. The mean conjunctival injection score was 0.69 for eyes on PG monotherapy and 0.56 for eyes on fixed combination therapy (P = 0.028). The mean SPK scores were 0.46 and 0.53. This difference was not statistically significant (P = 0.463). Conclusions. Switching from PG monotherapy to PG/b fixed combination therapy for NTG resulted in a greater intraocular pressure reduction than PG alone without increasing the number of instillations. PMID:25505978

  3. Improving sodium laser guide star brightness by polarization switching.

    PubMed

    Fan, Tingwei; Zhou, Tianhua; Feng, Yan

    2016-01-01

    Optical pumping with circularly polarized light has been used to enhance the brightness of sodium laser guide star. But the benefit is reduced substantially due to the precession of sodium atoms in geomagnetic field. Switching the laser between left and right circular polarization at the Larmor frequency is proposed to improve the return. With ESO's laser guide star system at Paranal as example, numerical simulation shows that the return flux is increased when the angle between geomagnetic field and laser beam is larger than 60°, as much as 50% at 90°. The proposal is significant since most astronomical observation is at angle between 60° and 90° and it only requires a minor addition to the delivery optics of present laser system. PMID:26797503

  4. Improving sodium laser guide star brightness by polarization switching

    PubMed Central

    Fan, Tingwei; Zhou, Tianhua; Feng, Yan

    2016-01-01

    Optical pumping with circularly polarized light has been used to enhance the brightness of sodium laser guide star. But the benefit is reduced substantially due to the precession of sodium atoms in geomagnetic field. Switching the laser between left and right circular polarization at the Larmor frequency is proposed to improve the return. With ESO’s laser guide star system at Paranal as example, numerical simulation shows that the return flux is increased when the angle between geomagnetic field and laser beam is larger than 60°, as much as 50% at 90°. The proposal is significant since most astronomical observation is at angle between 60° and 90° and it only requires a minor addition to the delivery optics of present laser system. PMID:26797503

  5. Improved apparatus for continuous culture of hydrogen-fixing bacteria

    NASA Technical Reports Server (NTRS)

    Foster, J. F.; Litchfield, J. H.

    1970-01-01

    Improved apparatus permits the continuous culture of Hydrogenomonas eutropha. System incorporates three essential subsystems - /1/ environmentally isolated culture vessel, /2/ analytical system with appropriate sensors and readout devices, /3/ control system with feedback responses to each analytical measurement.

  6. Improving the Energy Market: Algorithms, Market Implications, and Transmission Switching

    NASA Astrophysics Data System (ADS)

    Lipka, Paula Ann

    This dissertation aims to improve ISO operations through a better real-time market solution algorithm that directly considers both real and reactive power, finds a feasible Alternating Current Optimal Power Flow solution, and allows for solving transmission switching problems in an AC setting. Most of the IEEE systems do not contain any thermal limits on lines, and the ones that do are often not binding. Chapter 3 modifies the thermal limits for the IEEE systems to create new, interesting test cases. Algorithms created to better solve the power flow problem often solve the IEEE cases without line limits. However, one of the factors that makes the power flow problem hard is thermal limits on the lines. The transmission networks in practice often have transmission lines that become congested, and it is unrealistic to ignore line limits. Modifying the IEEE test cases makes it possible for other researchers to be able to test their algorithms on a setup that is closer to the actual ISO setup. This thesis also examines how to convert limits given on apparent power---as is in the case in the Polish test systems---to limits on current. The main consideration in setting line limits is temperature, which linearly relates to current. Setting limits on real or apparent power is actually a proxy for using the limits on current. Therefore, Chapter 3 shows how to convert back to the best physical representation of line limits. A sequential linearization of the current-voltage formulation of the Alternating Current Optimal Power Flow (ACOPF) problem is used to find an AC-feasible generator dispatch. In this sequential linearization, there are parameters that are set to the previous optimal solution. Additionally, to improve accuracy of the Taylor series approximations that are used, the movement of the voltage is restricted. The movement of the voltage is allowed to be very large at the first iteration and is restricted further on each subsequent iteration, with the restriction

  7. An improved switching control law for the optimized synchronous electric charge extraction circuit

    NASA Astrophysics Data System (ADS)

    Liu, Weiqun; Badel, Adrien; Formosa, Fabien; Liu, Congzhi; Hu, Guangdi

    2015-12-01

    Nonlinear switching interface circuits are considered as an efficient way to improve the performance of vibration energy harvesters. Among the various approaches, OSECE (Optimized Synchronous Electric Charge Extraction) exhibits satisfying properties: simple switching strategy, good performance in low coupling cases and low load dependency. However, the overdamping induced by the voltage inversion at maximal points leads to performance degeneration in high coupling cases. This paper presents an improved switching control law for the OSECE technique. The new OSECE_PT (OSECE with switching Phase Tuning) technique presented here is to let the switches act ahead or after the maximal point with a phase tuning. Theoretical analysis and numerical simulations show that the OSECE_PT technique can improve the power performance effectively and preserves desired load independence properties.

  8. RF MEMS Switches with SiC Microbridges for Improved Reliability

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximilian C.; Zorman, Christian A.; Oldham, Daniel R.

    2008-01-01

    Radio frequency (RF) microelectromechanical (MEMS) switches offer superior performance when compared to the traditional semiconductor devices such as PIN diodes or GaAs transistors. MEMS switches have a return loss (RL) better than -25 dB, negligible insertion loss (IL), isolation better than -30 dB, and near zero power consumption. However, RF MEMS switches have several drawbacks the most serious being long-term reliability. The ability for the switch to operate for millions or even billions of cycles is a major concern and must be addressed. MEMS switches are basically grouped in two categories, capacitive and metal-to-metal contact. The capacitive type switch consists of a movable metal bridge spanning a fixed electrode and separated by a narrow air gap and thin insulating material. The metal-to-metal contact type utilizes the same basic design but without the insulating material. After prolonged operation the metal bridges, in most of these switches, begin to sag and eventually fail to actuate. For the metal-to-metal type, the two metal layers may actually fuse together. Also if the switches are not packaged properly or protected from the environment moisture may build up and cause stiction between the top and bottom electrodes rendering them useless. Many MEMS switch designs have been developed and most illustrate fairly good RF characteristics. Nevertheless very few have demonstrated both great RF performance and ability to perform millions/billions of switching cycles. Of these, nearly all are of metal-to-metal type so as the frequency increases RF performance decreases.

  9. Development and fabrication of improved power transistor switches

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Chu, C. K.

    1979-01-01

    A new class of high-voltage power transistors was achieved by adapting present interdigitated thyristor processing techniques to the fabrication of npn Si transistors. Present devices are 2.3 cm in diameter and have V sub CEO (sus) in the range of 400 to 600V. V sub CEO (sus) = 450V devices were made with an (h sub FE)(I sub C) product of 900A at V sub CE = 2.5V. The electrical performance obtained was consistent with the predictions of an optimum design theory specifically developed for power switching transistors. The device design, wafer processing, and assembly techniques are described. Experimental measurements of the dc characteristics, forward SOA, and switching times are included. A new method of characterizing the switching performance of power transistors is proposed.

  10. Switching circuit to improve the frequency modulation difference-intensity THz quantum cascade laser imaging

    SciTech Connect

    Saat, N. K.; Dean, P.; Khanna, S. P.; Salih, M.; Linfield, E. H.; Davies, A. G.

    2015-04-24

    We demonstrate new switching circuit for difference-intensity THz quantum cascade laser (QCL) imaging by amplitude modulation and lock in detection. The switching circuit is designed to improve the frequency modulation so that it can stably lock the amplitude modulation of the QCL and the detector output. The combination of a voltage divider and a buffer in switching circuit to quickly switch the amplitude of the QCL biases of 15.8 V and 17.2 V is successfully to increase the frequency modulation up to ∼100 Hz.

  11. Improvement of resistive switching in NiO-based nanowires by inserting Pt layers

    NASA Astrophysics Data System (ADS)

    Huang, Yen-Chun; Chen, Po-Yuan; Chin, Tsung-Shune; Liu, Ru-Shi; Huang, Chao-Yuan; Lai, Chih-Huang

    2012-10-01

    Nonpolar resistive switching is demonstrated in polycrystalline NiO-based nanowires. The lower switching voltages and narrower switching distributions are exhibited in multilayered NiO/Pt nanowires, compared to the monolithic NiO nanowires. The temperature dependence of resistance at low resistance state reveals the conduction is attributed to the hopping through percolation paths composed of oxygen-related defects. The inserted Pt layers behave as intermediate electrodes to reduce migration length of oxygen ions and to store the oxygen ions near the electrodes. Therefore, the localized formation/migration of oxygen ions confines the occurrence of percolation paths, leading to improvement of the switching parameters.

  12. Magnetically operated limit switch has improved reliability, minimizes arcing

    NASA Technical Reports Server (NTRS)

    Steiner, R.

    1966-01-01

    Limit switch for reliable, low-travel, snap action with negligible arcing uses an electrically nonconductive permanent magnet consisting of a ferrimagnetic ceramic and ferromagnetic pole shoes which form a magnetic and electrically conductive circuit with a ferrous-metal armature.

  13. High accuracy switched-current circuits using an improved dynamic mirror

    NASA Technical Reports Server (NTRS)

    Zweigle, G.; Fiez, T.

    1991-01-01

    The switched-current technique, a recently developed circuit approach to analog signal processing, has emerged as an alternative/compliment to the well established switched-capacitor circuit technique. High speed switched-current circuits offer potential cost and power savings over slower switched-capacitor circuits. Accuracy improvements are a primary concern at this stage in the development of the switched-current technique. Use of the dynamic current mirror has produced circuits that are insensitive to transistor matching errors. The dynamic current mirror has been limited by other sources of error including clock-feedthrough and voltage transient errors. In this paper we present an improved switched-current building block using the dynamic current mirror. Utilizing current feedback the errors due to current imbalance in the dynamic current mirror are reduced. Simulations indicate that this feedback can reduce total harmonic distortion by as much as 9 dB. Additionally, we have developed a clock-feedthrough reduction scheme for which simulations reveal a potential 10 dB total harmonic distortion improvement. The clock-feedthrough reduction scheme also significantly reduces offset errors and allows for cancellation with a constant current source. Experimental results confirm the simulated improvements.

  14. Nanoscale switch based on interacting molecular dipoles: Cooperativity can improve the device characteristics

    NASA Astrophysics Data System (ADS)

    Mafé, , Salvador; Manzanares, , José A.; Reiss, Howard

    2011-02-01

    We propose a nanoscale switch, giving a nonlinear function with two conductive states separated by a sharp transition region, on the basis of an array of molecular dipoles. We show theoretically that the local interactions between dipoles result in cooperative phenomena that can significantly improve the switching characteristics. We demonstrate the general validity of the concept in the cases of (i) an electrical switch robust to the finite size and variability effects inherent to the nanoscale and (ii) a sensing layer based on the voltage and ligand concentration dependence of the dipole array conductance.

  15. Optimized Switch Allocation to Improve the Restoration Energy in Distribution Systems

    NASA Astrophysics Data System (ADS)

    Dezaki, Hamed H.; Abyaneh, Hossein A.; Agheli, Ali; Mazlumi, Kazem

    2012-01-01

    In distribution networks switching devices play critical role in energy restoration and improving reliability indices. This paper presents a novel objective function to optimally allocate switches in electric power distribution systems. Identifying the optimized location of the switches is a nonlinear programming problem (NLP). In the proposed objective function a new auxiliary function is used to simplify the calculation of the objective function. The output of the auxiliary function is binary. The genetic algorithm (GA) optimization method is used to solve this optimization problem. The proposed method is applied to a real distribution network and the results reveal that the method is successful.

  16. Gate-induced switching and negative differential resistance in a single-molecule transistor: emergence of fixed and shifting states with molecular length.

    PubMed

    Farajian, A A; Belosludov, R V; Mizuseki, H; Kawazoe, Y; Hashizume, T; Yakobson, B I

    2007-07-14

    The quantum transport of a gated polythiophene nanodevice is analyzed using density functional theory and nonequilibrium Green's function approach. For this typical molecular field effect transistor, we prove the existence of two main features of electronic components, i.e., negative differential resistance and good switching. Ab initio based explanations of these features are provided by distinguishing fixed and shifting conducting states, which are shown to arise from the interface and functional molecule, respectively. The results show that proper functional molecules can be used in conjunction with metallic electrodes to achieve basic electronics functionality at molecular length scales. PMID:17640145

  17. Miniature intermittent contact switch

    NASA Technical Reports Server (NTRS)

    Sword, A.

    1972-01-01

    Design of electric switch for providing intermittent contact is presented. Switch consists of flexible conductor surrounding, but separated from, fixed conductor. Flexing of outside conductor to contact fixed conductor completes circuit. Advantage is small size of switch compared to standard switches.

  18. Alarm toe switch

    DOEpatents

    Ganyard, Floyd P.

    1982-01-01

    An alarm toe switch inserted within a shoe for energizing an alarm circuit n a covert manner includes an insole mounting pad into which a miniature reed switch is fixedly molded. An elongated slot perpendicular to the reed switch is formed in the bottom surface of the mounting pad. A permanent cylindrical magnet positioned in the forward portion of the slot with a diameter greater than the pad thickness causes a bump above the pad. A foam rubber block is also positioned in the slot rearwardly of the magnet and holds the magnet in normal inoperative relation. A non-magnetic support plate covers the slot and holds the magnet and foam rubber in the slot. The plate minimizes bending and frictional forces to improve movement of the magnet for reliable switch activation. The bump occupies the knuckle space beneath the big toe. When the big toe is scrunched rearwardly the magnet is moved within the slot relative to the reed switch, thus magnetically activating the switch. When toe pressure is released the foam rubber block forces the magnet back into normal inoperative position to deactivate the reed switch. The reed switch is hermetically sealed with the magnet acting through the wall so the switch assembly S is capable of reliable operation even in wet and corrosive environments.

  19. Improved performance of a plasma opening switch using a novel anode configuration

    SciTech Connect

    Goyer, J.R.; Kortbawi, D.; Sincerny, P.S. )

    1994-06-01

    The performance of a plasma opening switch (POS), as measured by the peak opening voltage developed, has been improved from [approx] 1.2 to [approx] 2.3 MV through a simple modification of the anode electrode. This modification was motivated by observation of electron damage to the anode in the POS region, and consisted of the removal of any metallic surfaces that exhibited significant damage and were not essential to the integrity of the switch. Because present analytic theories and PIC simulations of the switch have not yet addressed the effect modifications to the anode may have to the opening phase in depth, it is hoped that in addition to providing a technique for improving POS operation, the work reported here may also provide incentive for further theoretical investigation.

  20. Improved design of long-span resin-bonded fixed partial dentures: three case reports.

    PubMed

    Botelho, Michael G

    2003-03-01

    When single-tooth implants are not appropriate, the use of resin-bonded fixed partial dentures is a preferred treatment option when the abutments are relatively sound. However, the use of resin-bonded fixed partial dentures (RBFPDs) for replacing two or more missing teeth is considered to have a guarded prognosis, as long-span RBFPDs have been shown to be less successful than single pontic prostheses. The use of properly modified nonrigid connectors may well improve the success of long-span RBFPDs by reducing harmful interabutment stresses that appear to be responsible for retainer debonding in long-span RBFPDs. For such long-span prostheses, it is advised that the major retainer have wraparound on at least three surfaces of the abutment or have strategically placed opposing axial grooves or slots. It is considered essential that the connector allow interabutment movement in both the horizontal and vertical planes so that the retainer with the greater resistance and retention form does not stress and possibly debond the minor retainer. The upside-down positioning of the nonrigid connector and the matrix incorporated with the major retainer is considered important for successful maintenance, if a debond should occur due to greater loading on the major retainer, because it can be removed and recemented easily. Clinical cases are described that replace two or more missing teeth using fixed-movable RBFPDs with nonrigid connectors. PMID:12731596

  1. Determination of αs(Mτ2) from improved fixed order perturbation theory

    NASA Astrophysics Data System (ADS)

    Abbas, Gauhar; Ananthanarayan, B.; Caprini, Irinel

    2012-05-01

    We revisit the extraction of αs(Mτ2) from the QCD perturbative corrections to the hadronic τ branching ratio, using an improved fixed-order perturbation theory based on the explicit summation of all renormalization-group accessible logarithms, proposed some time ago in the literature. In this approach, the powers of the coupling in the expansion of the QCD Adler function are multiplied by a set of functions Dn, which depend themselves on the coupling and can be written in a closed form by iteratively solving a sequence of differential equations. We find that the new expansion has an improved behavior in the complex energy plane compared to that of the standard fixed-order perturbation theory (FOPT), and is similar but not identical to the contour-improved perturbation theory (CIPT). With five terms in the perturbative expansion we obtain in the MS¯ scheme αs(Mτ2)=0.338±0.010, using as input a precise value for the perturbative contribution to the hadronic width of the τ lepton reported recently in the literature.

  2. An Improved SF6 System for the FXR Induction Linac Blumlein Switches

    SciTech Connect

    DeHope, W; Kihara, R; Griffin, K L; Ong, M; Ross, T

    2007-06-16

    The now-mature FXR (Flash X-Ray) radiographic facility at Lawrence Livermore National Laboratory will be briefly described with emphasis on its pulsed power system. The heart of each accelerating cell's pulse forming Blumlein is it's sulfur hexafluoride-based triggered closing switch. FXR's recent upgrade to a recirculating SF{sub 6} gas reclamation system will be described and the resulting accelerator performance and reliability improvements documented. This was accompanied by a detailed switch breakdown study on FXR's Test Stand and the recent analysis of the resulting statistics will be shown.

  3. Development and fabrication of improved power transistor switches. [fabrication and manufacturing of semiconductor devices

    NASA Technical Reports Server (NTRS)

    Hower, P. L.; Chu, C. K.

    1976-01-01

    A new class of high-voltage power transistors has been achieved by adapting present interdigitated thyristor processing techniques to the fabrication of NPN Si transistors. Present devices are 2.3 cm in diameter. The electrical performance obtained is consistent with the predictions of an optimum design theory specifically developed for power switching transistors. The forward safe operating area of the experimental transistors shows a significant improvement over commercially available devices. The report describes device design, wafer processing, and various measurements which include dc characteristics, forward and reverse second breakdown limits, and switching times.

  4. Nigella sativa fixed and essential oil improves antioxidant status through modulation of antioxidant enzymes and immunity.

    PubMed

    Sultan, Muhammad Tauseef; Butt, Masood Sadiq; Karim, Roselina; Ahmad, Nisar; Ahmad, Rabia Shabbir; Ahmad, Waqas

    2015-03-01

    The onset of 21st century witnessed the awareness among the masses regarding the diet-health linkages. The researchers attempted to explore traditional products/plants were in the domain of pharmacy and nutrition focussing on their health benefits. In the present research intervention, we investigate the role of Nigella sativa fixed oil (NSFO) and essential oil (NSEO) in improving antioxidant status and modulation of enzymes. The National Institute of Health (NIH) provided us 30 Sprague Dawley rats that were equally placed in three groups. The groups were fed on their respective diets (56 days) two experimental diets i.e. D2 (NSFO @ 4.0%) and D3 (NSEO @ 0.30%) and control. The indices pertaining to antioxidant status, antioxidant enzymes, and parameters pertaining to immunity were evaluated at 4 weeks interval. The experimental diets (NSFO@ 4.0% & NSEO@ 0.30%) modulated the activities of antioxidant enzymes i.e., catalase (CAT), superoxide dismutase (SOD), glutathione transferase (GST), glutathione reductase (GR) and glutathione peroxidase (GPx), positively. Indices of antioxidant status like tocopherols and glutathione were in linear relationship with that of GPx, GR and GST (P<0.01). Myeloperoxidase activities were in negative correlation with GST (P<0.01) but positive correlation with some other parameters. In the nutshell, the fixed and essential oil of Nigella sativa are effective in improving the indices pertaining to antioxidant status, however, the immune boosting potential needs further clarification. However, authors are of the view that there is need to explore the molecular targets of Nigella sativa fixed and essential oils. Findings from such studies would be useful to validate this instant study for health promoting potential against diabetes mellitus and cardiovascular disorders. PMID:25730812

  5. An improved chemically inducible gene switch that functions in the monocotyledonous plant sugar cane.

    PubMed

    Kinkema, Mark; Geijskes, R Jason; Shand, Kylie; Coleman, Heather D; De Lucca, Paulo C; Palupe, Anthony; Harrison, Mark D; Jepson, Ian; Dale, James L; Sainz, Manuel B

    2014-03-01

    Chemically inducible gene switches can provide precise control over gene expression, enabling more specific analyses of gene function and expanding the plant biotechnology toolkit beyond traditional constitutive expression systems. The alc gene expression system is one of the most promising chemically inducible gene switches in plants because of its potential in both fundamental research and commercial biotechnology applications. However, there are no published reports demonstrating that this versatile gene switch is functional in transgenic monocotyledonous plants, which include some of the most important agricultural crops. We found that the original alc gene switch was ineffective in the monocotyledonous plant sugar cane, and describe a modified alc system that is functional in this globally significant crop. A promoter consisting of tandem copies of the ethanol receptor inverted repeat binding site, in combination with a minimal promoter sequence, was sufficient to give enhanced sensitivity and significantly higher levels of ethanol inducible gene expression. A longer CaMV 35S minimal promoter than was used in the original alc gene switch also substantially improved ethanol inducibility. Treating the roots with ethanol effectively induced the modified alc system in sugar cane leaves and stem, while an aerial spray was relatively ineffective. The extension of this chemically inducible gene expression system to sugar cane opens the door to new opportunities for basic research and crop biotechnology. PMID:24142380

  6. Improved wavelength coded optical time domain reflectometry based on the optical switch.

    PubMed

    Zhu, Ninghua; Tong, Youwan; Chen, Wei; Wang, Sunlong; Sun, Wenhui; Liu, Jianguo

    2014-06-16

    This paper presents an improved wavelength coded time-domain reflectometry based on the 2 × 1 optical switch. In this scheme, in order to improve the signal-noise-ratio (SNR) of the beat signal, the improved system used an optical switch to obtain wavelength-stable, low-noise and narrow optical pulses for probe and reference. Experiments were set up to demonstrate a spatial resolution of 2.5m within a range of 70km and obtain the beat signal with line width narrower than 15 MHz within a range of 50 km in fiber break detection. A system for wavelength-division-multiplexing passive optical network (WDM-PON) monitoring was also constructed to detect the fiber break of different channels by tuning the current applied on the gating section of the distributed Bragg reflector (DBR) laser. PMID:24977604

  7. Longevity improvement of optically activated, high gain GaAs photoconductive semiconductor switches

    SciTech Connect

    MAR,ALAN; LOUBRIEL,GUILLERMO M.; ZUTAVERN,FRED J.; O'MALLEY,MARTIN W.; HELGESON,WESLEY D.; BROWN,DARWIN JAMES; HJALMARSON,HAROLD P.; BACA,ALBERT G.

    2000-03-02

    The longevity of high gain GaAs photoconductive semiconductor switches (PCSS) has been extended to over 100 million pulses at 23A, and over 100 pulses at 1kA. This is achieved by improving the ohmic contacts by doping the semi-insulating GaAs underneath the metal, and by achieving a more uniform distribution of contact wear across the entire switch by distributing the trigger light to form multiple filaments. This paper will compare various approaches to doping the contacts, including ion implantation, thermal diffusion, and epitaxial growth. The device characterization also includes examination of the filament behavior using open-shutter, infra-red imaging during high gain switching. These techniques provide information on the filament carrier densities as well as the influence that the different contact structures and trigger light distributions have on the distribution of the current in the devices. This information is guiding the continuing refinement of contact structures and geometries for further improvements in switch longevity.

  8. Deep Brain Stimulation of the Subthalamic Nucleus Improves Lexical Switching in Parkinsons Disease Patients

    PubMed Central

    Vonberg, Isabelle; Ehlen, Felicitas; Fromm, Ortwin; Kühn, Andrea A.; Klostermann, Fabian

    2016-01-01

    Objective Reduced verbal fluency (VF) has been reported in patients with Parkinson’s disease (PD), especially those treated by Deep Brain Stimulation of the subthalamic nucleus (STN DBS). To delineate the nature of this dysfunction we aimed at identifying the particular VF-related operations modified by STN DBS. Method Eleven PD patients performed VF tasks in their STN DBS ON and OFF condition. To differentiate VF-components modulated by the stimulation, a temporal cluster analysis was performed, separating production spurts (i.e., ‘clusters’ as correlates of automatic activation spread within lexical fields) from slower cluster transitions (i.e., ‘switches’ reflecting set-shifting towards new lexical fields). The results were compared to those of eleven healthy control subjects. Results PD patients produced significantly more switches accompanied by shorter switch times in the STN DBS ON compared to the STN DBS OFF condition. The number of clusters and time intervals between words within clusters were not affected by the treatment state. Although switch behavior in patients with DBS ON improved, their task performance was still lower compared to that of healthy controls. Discussion Beyond impacting on motor symptoms, STN DBS seems to influence the dynamics of cognitive procedures. Specifically, the results are in line with basal ganglia roles for cognitive switching, in the particular case of VF, from prevailing lexical concepts to new ones. PMID:27575379

  9. A low power 12-bit 1 Msps successive approximation register ADC with an improved switching procedure

    NASA Astrophysics Data System (ADS)

    Fubin, Xin; Tao, Yin; Qisong, Wu; Yuanlong, Yang; Fei, Liu; Haigang, Yang

    2015-08-01

    As a key building block of data acquisition systems, power dissipation of the successive approximation register (SAR) ADC determines the total power consumption of the system. In this paper, a low power 12-bit 1 Msps SAR ADC with an improved switching procedure is presented. Power consumption and area occupation could be significantly reduced by using the proposed switching procedure. Compared to converters that use the conventional switching procedure, the average switching energy could be reduced by about 80% and the total capacitance could be reduced by 50%. A simplified digital control logic is utilized to reduce power dissipation and area occupation of the digital control circuits. Simulation results show that the power dissipated by the proposed digital control circuits could be reduced by about 50% compared to the power dissipated by conventional control circuits. The chip has been processed in a standard 0.35 μm CMOS technology and has a core die area of 1.12 mm2. A signal-to-noise-and-distortion-ratio of 64.2 dB has been measured with a 100 kHz signal input under a wide range variation of temperature from -55 to 150 °C. The total power consumption of the prototype is only 0.72 mW with a 3.3 V supply voltage. Project supported by the National Basic Research Program of China (No. 2014CB744600) and the National Natural Science Foundation of China (No. 61474120).

  10. Improved Equivalent Circuit Model for V-Shaped, Thresholdless Switching Ferroelectric Liquid Crystals

    NASA Astrophysics Data System (ADS)

    Wang, Meng-yao; Pan, Wei; Luo, Bin; Zhang, Wei-li; Zou, Xi-hua

    2008-05-01

    For V-shaped, thresholdless switching ferroelectric liquid crystals (FLCs), the impedance divider induced by the multilayer structure of FLC cells and the drive circuit play an important role in switching characteristics. In this paper, an equivalent circuit model that can be applied to conventional circuit simulators is proposed for the optical response prediction and drive circuit optimization of V-shaped FLCs. The model is improved from the original model of Moore and Travis; however, the impedance divider is taken into account, and both polar and nonpolar surface anchoring energies are considered to make the model more preferable. The model is then utilized to investigate thresholdless switching characteristics. Simulation results show that the hysteresis inversion frequency fi increases more than one thousand fold with the drive circuit and then decreases with REXT following the relation log fi = -alog REXT + b, and a (b) increases from 0.43 to 0.46 (2.46 to 2.66) as the amplitude of triangular voltage increases from 4 to 10 V, agreeing with experimental results. Also, the same optical transmissions are plotted as different coordinates, as a function of voltage dropping on liquid crystal layer and of drive voltage, and the results show that genuine V-shaped switching is only observed when the transmission is plotted as a function of drive voltage, coinciding with the model suggested by Blinov et al.

  11. Improvement in Neural Respiratory Drive Estimation From Diaphragm Electromyographic Signals Using Fixed Sample Entropy.

    PubMed

    Estrada, Luis; Torres, Abel; Sarlabous, Leonardo; Jane, Raimon

    2016-03-01

    Diaphragm electromyography is a valuable technique for the recording of electrical activity of the diaphragm. The analysis of diaphragm electromyographic (EMGdi) signal amplitude is an alternative approach for the quantification of the neural respiratory drive (NRD). The EMGdi signal is, however, corrupted by electrocardiographic (ECG) activity, and this presence of cardiac activity can make the EMGdi interpretation more difficult. Traditionally, the EMGdi amplitude has been estimated using the average rectified value (ARV) and the root mean square (RMS). In this study, surface EMGdi signals were analyzed using the fixed sample entropy (fSampEn) algorithm, and compared to the traditional ARV and RMS methods. The fSampEn is calculated using a tolerance value fixed and independent of the standard deviation of the analysis window. Thus, this method quantifies the amplitude of the complex components of stochastic signals (such as EMGdi), and being less affected by changes in amplitude due to less complex components (such as ECG). The proposed method was tested in synthetic and recorded EMGdi signals. fSampEn was less sensitive to the effect of cardiac activity on EMGdi signals with different levels of NRD than ARV and RMS amplitude parameters. The mean and standard deviation of the Pearson's correlation values between inspiratory mouth pressure (an indirect measure of the respiratory muscle activity) and fSampEn, ARV, and RMS parameters, estimated in the recorded EMGdi signal at tidal volume (without inspiratory load), were 0.38±0.12, 0.27±0.11 , and 0.11±0.13, respectively. Whereas at 33 cmH2O (maximum inspiratory load) were 0.83±0.02, 0.76±0.07, and 0.61±0.19 , respectively. Our findings suggest that the proposed method may improve the evaluation of NRD. PMID:25667362

  12. A microfabricated fixed path length silicon sample holder improves background subtraction for cryoSAXS

    PubMed Central

    Hopkins, Jesse B.; Katz, Andrea M.; Meisburger, Steve P.; Warkentin, Matthew A.; Thorne, Robert E.; Pollack, Lois

    2015-01-01

    The application of small-angle X-ray scattering (SAXS) for high-throughput characterization of biological macromolecules in solution is limited by radiation damage. By cryocooling samples, radiation damage and required sample volumes can be reduced by orders of magnitude. However, the challenges of reproducibly creating the identically sized vitrified samples necessary for conventional background subtraction limit the widespread adoption of this method. Fixed path length silicon sample holders for cryoSAXS have been microfabricated to address these challenges. They have low background scattering and X-ray absorption, require only 640 nl of sample, and allow reproducible sample cooling. Data collected in the sample holders from a nominal illuminated sample volume of 2.5 nl are reproducible down to q ≃ 0.02 Å−1, agree with previous cryoSAXS work and are of sufficient quality for reconstructions that match measured crystal structures. These sample holders thus allow faster, more routine cryoSAXS data collection. Additional development is required to reduce sample fracturing and improve data quality at low q. PMID:26089749

  13. Input Power Quality Improvement in Switched Reluctance Motor Drive using Minnesota Rectifier

    NASA Astrophysics Data System (ADS)

    Singh, B.; Rajesh, M.

    2013-09-01

    This paper deals with an input power quality improvement in a midpoint converter based switched reluctance motor (SRM) drive at ac mains using Minnesota rectifier. Normally a midpoint converter is used as a power converter for SRM drive. Conventionally three phase ac mains fed bridge rectifier is used as a dc source to feed this power converter which produces high content of harmonics at ac mains with a very low power factor. The proposed Minnesota rectifier with a midpoint converter fed SRM drive improves the power factor at ac mains with low current harmonics. This method provides constant dc link voltage and balanced capacitor voltages of the midpoint converter. The Minnesota rectifier fed SRM drive is modelled and its performance is simulated in Matlab/Simulink environment. The performance of Minnesota rectifier is compared with a conventional bridge topology for SRM drive to demonstrate improved power quality at ac mains.

  14. L-theanine and caffeine improve task switching but not intersensory attention or subjective alertness.

    PubMed

    Einöther, Suzanne J L; Martens, Vanessa E G; Rycroft, Jane A; De Bruin, Eveline A

    2010-04-01

    Tea ingredients L-theanine and caffeine have repeatedly been shown to deliver unique cognitive benefits when consumed in combination. The current randomized, placebo-controlled, double-blind, cross-over study compared a combination of L-theanine (97 mg) and caffeine (40 mg) to a placebo on two attention tasks and a self-report questionnaire before, and 10 and 60 min after consumption. The combination of L-theanine and caffeine significantly improved attention on a switch task as compared to the placebo, while subjective alertness and intersensory attention were not improved significantly. The results support previous evidence that L-theanine and caffeine in combination can improve attention. PMID:20079786

  15. Improving performance of the metal-to-metal contact RF MEMS switch with a Pt-Au microspring contact design

    NASA Astrophysics Data System (ADS)

    Liu, Bo; Lv, Zhiqiu; He, Xunjun; Liu, Meng; Hao, Yilong; Li, Zhihong

    2011-06-01

    Performances of the metal-to-metal contact radio frequency (RF) MEMS switches largely rely on the contacts. A novel contact employing the microspring structure is demonstrated in this paper. The microspring contact can achieve a stable contact at lower actuation voltage, alleviating mechanical wear on the contacts, and can effectively increase the fabrication tolerance. An in-line Pt-Au microspring contact switch was fabricated and characterized. To evaluate the improvement in performance, the results were compared with those of the Au-Au solid contact switch without a microspring design. The highest current handled by the Pt-Au microspring contact was 150 mA per contact, whereas only 20 mA was handled by the Au-Au solid contact. The insertion loss of the Pt-Au microspring contact switch was -0.2 dB at 20 GHz, which was comparable with that of the Au-Au solid contact switch. The isolation of the Pt-Au microspring contact switch was -22 dB at 20 GHz, and that of the Au-Au solid contact switch was -18 dB. With the Pt-Au microspring contact, the switch exceeds its power handling ability and reliability with comparable RF performances.

  16. Switch from intravenous to subcutaneous immunoglobulin in CIDP and MMN: improved tolerability and patient satisfaction

    PubMed Central

    Marreno, Fabrizio

    2015-01-01

    Objectives: To assess clinical outcomes and patient satisfaction in patients with chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) or multifocal motor neuropathy (MMN) who were switched from intravenous immunoglobulin (IVIG) to subcutaneous immunoglobulin (SCIG). Methods: Eight consecutive patients, four with MMN and four with CIDP, already on long-term, hospital-based IVIG were switched to home-based SCIG. These patients were selected on the basis of their requirement for relatively low treatment doses, problems experienced with IVIG, and their willingness to switch to SCIG. Results: After a mean 33 [standard deviation (SD) 19] months receiving SCIG, 7 patients remained neurologically stable and 6 remained on a similar mean weekly immunoglobulin dose relative to their original intravenous dose. A good outcome was reported by 7 of the 8 patients: there were improvements in nausea and headache (n = 4), need to travel to hospital (n = 4), venous access problems (n = 3), immunoglobulin-induced neutropenia (n = 3), treatment wearing-off fluctuations (n = 2), IVIG-induced allergy requiring antihistamine/hydrocortisone (n = 1) and time taken off work (n = 1). The eighth patient required increasing doses of immunoglobulin to maintain strength but still wanted to continue SCIG. Seven patients completed a questionnaire: there was a very high overall satisfaction level with immunoglobulin treatment [mean 96 (SD 5), visual analogue scale (VAS) where 0 = very unsatisfied, 100 = very satisfied]; and very strong preference for subcutaneous over intravenous immunoglobulin (VAS mean 93 [SD 12] where 0 = prefer IVIG, 100 = prefer SCIG). Conclusions: In seven of the eight patients, SCIG gave improved tolerability and patient satisfaction with similar efficacy compared with IVIG. PMID:25584070

  17. Combining GPS + GLONASS observations to improve the fixing percentage and precision of long baselines with limited data

    NASA Astrophysics Data System (ADS)

    Liu, Yanyan; Ye, Shirong; Jiang, Peng; Song, Weiwei; Lou, Yidong

    2016-03-01

    Although commercial GPS + GLONASS real-time kinematic systems are available for more than 15 years, GLONASS ambiguity resolution is limited to short baselines within a few tens of kilometers. Furthermore, until now, none of the IGS analysis center has reported ambiguity resolution for GLONASS long baselines in their routine GNSS data processing. The currently published double- or single-differencing techniques are all concentrated on short baselines and are not applicable for long baselines. In this study, we propose a new Single Differencing Between-Receiver (SDBR) method, which is especially suitable for GPS + GLONASS long baseline ambiguity resolution. The SDBR wide-lane ambiguity is directly fixed by rounding with SDBR Hatch-Melbourne-Wübbena combination; the SDBR narrow-lane ambiguity is directly fixed with LAMBDA method. To eliminate the receiver Inter Frequency Bias (IFB), we selected 63 stations with identical IFBs, so that IFBs can be eliminated by SDBR. The results shows, adding GLONASS can improve the fixing rate from 87.8% to 98.8% for half-hourly static solutions, and from 99.3% to 99.9% for hourly static solutions. The position accuracy is also improved significantly for each strategy respectively. Kinematic solutions with different session length are also performed and the fixing rate is improved even more significantly than static solutions.

  18. Improved RDX detoxification with starch addition using a novel nitrogen-fixing aerobic microbial consortium from soil contaminated with explosives.

    PubMed

    Khan, Muhammad Imran; Yang, Jihoon; Yoo, Byungun; Park, Joonhong

    2015-04-28

    In this work, we developed and characterized a novel nitrogen-fixing aerobic microbial consortium for the complete detoxification of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX). Aerobic RDX biodegradation coupled with microbial growth and nitrogen fixation activity were effectively stimulated by the co-addition of starch and RDX under nitrogen limiting conditions. In the starch-stimulated nitrogen-fixing RDX degradative consortium, the RDX degradation activity was correlated with the xplA and nifH gene copy numbers, suggesting the involvement of nitrogen fixing populations in RDX biodegradation. Formate, nitrite, nitrate, and ammonia were detected as aerobic RDX degradation intermediates without the accumulation of any nitroso-derivatives or NDAB (4-nitro-2,4-diazabutanal), indicating nearly complete mineralization. Pyrosequencing targeting the bacterial 16S rRNA genes revealed that the Rhizobium, Rhizobacter and Terrimonas population increased as the RDX degradation activity increased, suggesting their involvement in the degradation process. These findings imply that the nitrogen-fixing aerobic RDX degrading consortium is a valuable microbial resource for improving the detoxification of RDX-contaminated soil or groundwater, especially when combined with rhizoremediation. PMID:25661171

  19. Improved Alkane Production in Nitrogen-Fixing and Halotolerant Cyanobacteria via Abiotic Stresses and Genetic Manipulation of Alkane Synthetic Genes.

    PubMed

    Kageyama, Hakuto; Waditee-Sirisattha, Rungaroon; Sirisattha, Sophon; Tanaka, Yoshito; Mahakhant, Aparat; Takabe, Teruhiro

    2015-07-01

    Cyanobacteria possess the unique capacity to produce alkane. In this study, effects of nitrogen deficiency and salt stress on biosynthesis of alkanes were investigated in three kinds of cyanobacteria. Intracellular alkane accumulation was increased in nitrogen-fixing cyanobacterium Anabaena sp. PCC7120, but decreased in non-diazotrophic cyanobacterium Synechococcus elongatus PCC7942 and constant in a halotolerant cyanobacterium Aphanothece halophytica under nitrogen-deficient condition. We also found that salt stress increased alkane accumulation in Anabaena sp. PCC7120 and A. halophytica. The expression levels of two alkane synthetic genes were not upregulated significantly under nitrogen deficiency or salt stress in Anabaena sp. PCC7120. The transformant Anabaena sp. PCC7120 cells with additional alkane synthetic gene set from A. halophytica increased intracellular alkane accumulation level compared to control cells. These results provide a prospect to improve bioproduction of alkanes in nitrogen-fixing halotolerant cyanobacteria via abiotic stresses and genetic engineering. PMID:25971893

  20. Three phase six-switch PWM buck rectifier with power factor improvement

    NASA Astrophysics Data System (ADS)

    Zafarullah Khan, M.; Mohsin Naveed, M.; Akbar Hussain, D. M.

    2013-06-01

    Conventional Phase Controlled Rectifier injects low order current harmonics into the AC mains. Large size filtering components are required to attenuate these harmonics. In this paper, three phase six-switch PWM buck rectifier is presented which operates at nearly unity power factor and provides variable output voltage. Small size energy storing components are required depending upon switching frequency. MATLAB simulation is performed and modified Sinusoidal Pulse Width Modulation (SPWM) switching technique is used in 3kW prototype converter to demonstrate low input current THD, nearly unity displacement factor, well regulated output voltage and reduced switching losses compared to conventional SPWM.

  1. Coherent switching with decay of mixing: An improved treatment of electronic coherence for non-Born-Oppenheimer trajectories

    NASA Astrophysics Data System (ADS)

    Zhu, Chaoyuan; Nangia, Shikha; Jasper, Ahren W.; Truhlar, Donald G.

    2004-10-01

    The self-consistent decay-of-mixing (SCDM) semiclassical trajectory method for electronically nonadiabatic dynamics is improved by modifying the switching probability that determines the instantaneous electronic state toward which the system decoheres. This method is called coherent switching with decay of mixing (CSDM), and it differs from the previously presented SCDM method in that the electronic amplitudes controlling the switching of the decoherent state are treated fully coherently in the electronic equations of motion for each complete passage through a strong interaction region. It is tested against accurate quantum mechanical calculations for 12 atom-diatom scattering test cases. Also tested are the SCDM method and the trajectory surface hopping method of Parlant and Gislason that requires coherent passages through each strong interaction region, and which we call the "exact complete passage" trajectory surface hopping (ECP-TSH) method. The results are compared with previously presented results for the fewest switches with time uncertainty and Tully's fewest switches (TFS) surface hopping methods and the semiclassical Ehrenfest method. We find that the CSDM method is the most accurate of the semiclassical trajectory methods tested. Including coherent passages improves the accuracy of the SCDM method (i.e., the CSDM method is more accurate than the SCDM method) but not of the trajectory surface hopping method (i.e., the ECP-TSH method is not more accurate on average than the TFS method).

  2. Alarm toe switch. [Patent application

    DOEpatents

    Ganyard, F.P.

    1980-11-18

    An alarm toe switch inserted within a shoe for energizing an alarm circuit in a covert manner includes an insole mounting pad into which a miniature reed switch is fixedly molded. An elongated slot perpendicular to the reed switch is formed in the bottom surface of the mounting pad. A permanent cylindrical magnet positioned in the forward portion of the slot with a diameter greater than the pad thickness causes a bump above the pad. A foam rubber block is also positioned in the slot rearwardly of the magnet and holds the magnet in normal inoperative relation. A non-magnetic support plate covers the slot and holds the magnet and foam rubber in the slot. The plate minimizes bending and frictional forces to improve movement of the magnet for reliable switch activation. The bump occupies the knuckle space beneath the big toe. When the big toe is scrunched rearwardly the magnet is moved within the slot relative to the reed switch, thus magnetically activating the switch. When toe pressure is released the foam rubber block forces the magnet back into normal inoperative position to deactivate the reed switch.

  3. Latching micro optical switch

    DOEpatents

    Garcia, Ernest J; Polosky, Marc A

    2013-05-21

    An optical switch reliably maintains its on or off state even when subjected to environments where the switch is bumped or otherwise moved. In addition, the optical switch maintains its on or off state indefinitely without requiring external power. External power is used only to transition the switch from one state to the other. The optical switch is configured with a fixed optical fiber and a movable optical fiber. The movable optical fiber is guided by various actuators in conjunction with a latching mechanism that configure the switch in one position that corresponds to the on state and in another position that corresponds to the off state.

  4. Constrained fixed-fulcrum reverse shoulder arthroplasty improves functional outcome in epileptic patients with recurrent shoulder instability

    PubMed Central

    Thangarajah, Tanujan; Higgs, Deborah; Bayley, J I L; Lambert, Simon M

    2016-01-01

    AIM: To report the results of fixed-fulcrum fully constrained reverse shoulder arthroplasty for the treatment of recurrent shoulder instability in patients with epilepsy. METHODS: A retrospective review was conducted at a single facility. Cases were identified using a computerized database and all clinic notes and operative reports were reviewed. All patients with epilepsy and recurrent shoulder instability were included for study. Between July 2003 and August 2011 five shoulders in five consecutive patients with epilepsy underwent fixed-fulcrum fully constrained reverse shoulder arthroplasty for recurrent anterior shoulder instability. The mean duration of epilepsy in the cohort was 21 years (range, 5-51) and all patients suffered from grand mal seizures. RESULTS: Mean age at the time of surgery was 47 years (range, 32-64). The cohort consisted of four males and one female. Mean follow-up was 4.7 years (range, 4.3-5 years). There were no further episodes of instability, and no further stabilisation or revision procedures were performed. The mean Oxford shoulder instability score improved from 8 preoperatively (range, 5-15) to 30 postoperatively (range, 16-37) (P = 0.015) and the mean subjective shoulder value improved from 20 (range, 0-50) preoperatively to 60 (range, 50-70) postoperatively (P = 0.016). Mean active forward elevation improved from 71° preoperatively (range, 45°-130°) to 100° postoperatively (range, 80°-90°) and mean active external rotation improved from 15° preoperatively (range, 0°-30°) to 40° (20°-70°) postoperatively. No cases of scapular notching or loosening were noted. CONCLUSION: Fixed-fulcrum fully constrained reverse shoulder arthroplasty should be considered for the treatment of recurrent shoulder instability in patients with epilepsy. PMID:27458554

  5. Acceleration switch

    DOEpatents

    Abbin, J.P. Jr.; Devaney, H.F.; Hake, L.W.

    1979-08-29

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  6. Acceleration switch

    DOEpatents

    Abbin, Jr., Joseph P.; Devaney, Howard F.; Hake, Lewis W.

    1982-08-17

    The disclosure relates to an improved integrating acceleration switch of the type having a mass suspended within a fluid filled chamber, with the motion of the mass initially opposed by a spring and subsequently not so opposed.

  7. Improved TNT detoxification by starch addition in a nitrogen-fixing Methylophilus-dominant aerobic microbial consortium.

    PubMed

    Khan, Muhammad Imran; Lee, Jaejin; Yoo, Keunje; Kim, Seonghoon; Park, Joonhong

    2015-12-30

    In this study, a novel aerobic microbial consortium for the complete detoxification of 2,4,6-trinitrotoluene (TNT) was developed using starch as a slow-releasing carbon source under nitrogen-fixing conditions. Aerobic TNT biodegradation coupled with microbial growth was effectively stimulated by the co-addition of starch and TNT under nitrogen-fixing conditions. The addition of starch with TNT led to TNT mineralization via ring cleavage without accumulation of any toxic by-products, indicating improved TNT detoxification by the co-addition of starch and TNT. Pyrosequencing targeting the bacterial 16S rRNA gene suggested that Methylophilus and Pseudoxanthomonas population were significantly stimulated by the co-addition of starch and TNT and that the Methylophilus population became predominant in the consortium. Together with our previous study regarding starch-stimulated RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) degradation (Khan et al., J. Hazard. Mater. 287 (2015) 243-251), this work suggests that the co-addition of starch with a target explosive is an effective way to stimulate aerobic explosive degradation under nitrogen-fixing conditions for enhancing explosive detoxification. PMID:26342802

  8. Behavioural effects of fixed speed cameras on motorways: overall improved speed compliance or kangaroo jumps?

    PubMed

    De Pauw, Ellen; Daniels, Stijn; Brijs, Tom; Hermans, Elke; Wets, Geert

    2014-12-01

    The present study evaluates the speed effects of fixed speed cameras on motorways. Two locations with speed cameras were extensively examined in a quasi-experiment: (1) a two-lane motorway and (2) a three-lane motorway, each with a posted speed limit of 120 km/h and sited in Flanders, Belgium. The effect is analysed through a before-and-after comparison of travel speeds. General time trends and fluctuations were controlled through the analysis of the speeds at comparison locations. At each of the two roads, data were gathered at five measurement points from 3 km upstream to 3.8 km downstream of the camera. Three outcomes were analysed: (1) average speed, (2) the odds of drivers exceeding the speed limit and (3) the odds of drivers exceeding the speed limit by more than 10%. Speeds decreased on average by 6.4 km/h at the camera locations. Both the odds of drivers exceeding the speed limit (-80%) and the odds of drivers exceeding the speed limit by more than 10% (-86%) decreased considerably. However, before and beyond the cameras the speeds hardly, if at all, reduced. Moreover, the analyses of the speed profiles before and beyond the cameras show that drivers do slow down quite abruptly before the camera and speed up again after passing the camera. It is concluded that a V-profile is found in the spatial speed distribution for both locations. PMID:25217731

  9. Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media

    NASA Astrophysics Data System (ADS)

    Suess, D.; Fuger, M.; Abert, C.; Bruckner, F.; Vogler, C.

    2016-06-01

    We report two effects that lead to a significant reduction of the switching field distribution in exchange spring media. The first effect relies on a subtle mechanism of the interplay between exchange coupling between soft and hard layers and anisotropy that allows significant reduction of the switching field distribution in exchange spring media. This effect reduces the switching field distribution by about 30% compared to single-phase media. A second effect is that due to the improved thermal stability of exchange spring media over single-phase media, the jitter due to thermal fluctuation is significantly smaller for exchange spring media than for single-phase media. The influence of this overall improved switching field distribution on the transition jitter in granular recording and the bit error rate in bit-patterned magnetic recording is discussed. The transition jitter in granular recording for a distribution of Khard values of 3% in the hard layer, taking into account thermal fluctuations during recording, is estimated to be a = 0.78 nm, which is similar to the best reported calculated jitter in optimized heat-assisted recording media.

  10. Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media.

    PubMed

    Suess, D; Fuger, M; Abert, C; Bruckner, F; Vogler, C

    2016-01-01

    We report two effects that lead to a significant reduction of the switching field distribution in exchange spring media. The first effect relies on a subtle mechanism of the interplay between exchange coupling between soft and hard layers and anisotropy that allows significant reduction of the switching field distribution in exchange spring media. This effect reduces the switching field distribution by about 30% compared to single-phase media. A second effect is that due to the improved thermal stability of exchange spring media over single-phase media, the jitter due to thermal fluctuation is significantly smaller for exchange spring media than for single-phase media. The influence of this overall improved switching field distribution on the transition jitter in granular recording and the bit error rate in bit-patterned magnetic recording is discussed. The transition jitter in granular recording for a distribution of Khard values of 3% in the hard layer, taking into account thermal fluctuations during recording, is estimated to be a = 0.78 nm, which is similar to the best reported calculated jitter in optimized heat-assisted recording media. PMID:27245287

  11. Superior bit error rate and jitter due to improved switching field distribution in exchange spring magnetic recording media

    PubMed Central

    Suess, D.; Fuger, M.; Abert, C.; Bruckner, F.; Vogler, C.

    2016-01-01

    We report two effects that lead to a significant reduction of the switching field distribution in exchange spring media. The first effect relies on a subtle mechanism of the interplay between exchange coupling between soft and hard layers and anisotropy that allows significant reduction of the switching field distribution in exchange spring media. This effect reduces the switching field distribution by about 30% compared to single-phase media. A second effect is that due to the improved thermal stability of exchange spring media over single-phase media, the jitter due to thermal fluctuation is significantly smaller for exchange spring media than for single-phase media. The influence of this overall improved switching field distribution on the transition jitter in granular recording and the bit error rate in bit-patterned magnetic recording is discussed. The transition jitter in granular recording for a distribution of Khard values of 3% in the hard layer, taking into account thermal fluctuations during recording, is estimated to be a = 0.78 nm, which is similar to the best reported calculated jitter in optimized heat-assisted recording media. PMID:27245287

  12. Switching antipsychotic therapy: what to expect and clinical strategies for improving therapeutic outcomes.

    PubMed

    Lambert, Tim J

    2007-01-01

    When a patient taking an antipsychotic is not experiencing symptomatic remission, or is experiencing adverse effects (AEs) that are intolerable or damaging to his or her physical health, a change in medication may be the best path to a good outcome. However, many clinicians are reluctant to switch medications in all but the clearest cases of failure. This reluctance is intensified by the occurrence of AEs caused by transitioning patients too rapidly between agents with different receptor-binding profiles. Emergent antipsychotic-switching syndromes include the "withdrawal triad," comprised of cholinergic rebound, supersensitivity psychosis, and emergent withdrawal dyskinesias (and other motor syndromes). More recently, another element has been observed consistent with an activation syndrome. This activation syndrome may occur as a consequence of switching from highly sedative agents or as a consequence of initial prodopaminergic drive. All of these effects can be minimized by careful planning of gradual switch procedures and judicious use of adjunctive medications. PMID:17650054

  13. Improved Endurance and Resistive Switching Stability in Ceria Thin Films Due to Charge Transfer Ability of Al Dopant.

    PubMed

    Ismail, M; Ahmed, E; Rana, A M; Hussain, F; Talib, I; Nadeem, M Y; Panda, D; Shah, N A

    2016-03-01

    An improvement in resistive switching (RS) characteristics of CeO2-based devices has been reported by charge transfer through Al metal as a dopant. Moreover, density functional theory (DFT) calculations have been performed to investigate the role of Al-layer sandwiched between CeO2 layers by the Vienna ab initio simulation package (VASP). Total density of states (TDOS) and partial electron density of states (PDOS) have been calculated and analyzed with respect to resistive switching. It is established that the oxygen vacancy based conductive filaments are formed and ruptured in the upper region of CeO2 layer, because of the fact that maximum transport of charge takes place in this region by Al and Ti (top electrode), while the lower region revealed less capability to generate conductive filaments because minimum charge transfer takes place in this region by Al and/or Pt (bottom electrode). The effect of Al and Al2O3 on both the electronic charge transfer from valence to conduction bands and the formation stability of oxygen vacancies in conductive filament have been discussed in detail. Experimental results demonstrated that the Ti/CeO2:Al/Pt sandwich structure exhibits significantly better switching characteristics including lower forming voltage, improved and stable SET/RESET voltages, enhanced endurance of more than 10(4) repetitive switching cycles and large memory window (ROFF/RON > 10(2)) as compared to undoped Ti/CeOx/Pt device. This improvement in memory switching behavior has been attributed to a significant decrease in the formation energy of oxygen vacancies and to the enhanced oxygen vacancies generation within the CeO2 layers owing to charge transferring and oxygen gettering ability of Al-dopant. PMID:26881895

  14. On improvements of neural network accuracy with fixed number of active neurons

    NASA Astrophysics Data System (ADS)

    Sokolova, Natalia; Nikolaev, Dmitry P.; Polevoy, Dmitry

    2015-02-01

    In this paper an improvement possibility of multilayer perceptron based classifiers with using composite classifier scheme with predictor function was exploited. Recognition of embossed number characters on plastic cards in the image taken by mobile camera was used as a model problem.

  15. Improved reproducibility in genome-wide DNA methylation analysis for PAXgene-fixed samples compared with restored formalin-fixed and paraffin-embedded DNA.

    PubMed

    Andersen, Gitte Brinch; Hager, Henrik; Hansen, Lise Lotte; Tost, Jörg

    2015-01-01

    Formalin fixation has been the standard method for conservation of clinical specimens for decades. However, a major drawback is the high degradation of nucleic acids, which complicates its use in genome-wide analyses. Unbiased identification of biomarkers, however, requires genome-wide studies, precluding the use of the valuable archives of specimens with long-term follow-up data. Therefore, restoration protocols for DNA from formalin-fixed and paraffin-embedded (FFPE) samples have been developed, although they are cost-intensive and time-consuming. An alternative to FFPE and snap-freezing is the PAXgene Tissue System, developed for simultaneous preservation of morphology, proteins, and nucleic acids. In the current study, we compared the performance of DNA from either PAXgene or formalin-fixed tissues to snap-frozen material for genome-wide DNA methylation analysis using the Illumina 450K BeadChip. Quantitative DNA methylation analysis demonstrated that the methylation profile in PAXgene-fixed tissues showed, in comparison with restored FFPE samples, a higher concordance with the profile detected in frozen samples. We demonstrate, for the first time, that DNA from PAXgene conserved tissue performs better compared with restored FFPE DNA in genome-wide DNA methylation analysis. In addition, DNA from PAXgene tissue can be directly used on the array without prior restoration, rendering the analytical process significantly more time- and cost-effective. PMID:25277813

  16. Improving Inertial Pedestrian Dead-Reckoning by Detecting Unmodified Switched-on Lamps in Buildings

    PubMed Central

    Jiménez, Antonio R.; Zampella, Francisco; Seco, Fernando

    2014-01-01

    This paper explores how inertial Pedestrian Dead-Reckoning (PDR) location systems can be improved with the use of a light sensor to measure the illumination gradients created when a person walks under ceiling-mounted unmodified indoor lights. The process of updating the inertial PDR estimates with the information provided by light detections is a new concept that we have named Light-matching (LM). The displacement and orientation change of a person obtained by inertial PDR is used by the LM method to accurately propagate the location hypothesis, and vice versa; the LM approach benefits the PDR approach by obtaining an absolute localization and reducing the PDR-alone drift. Even from an initially unknown location and orientation, whenever the person passes below a switched-on light spot, the location likelihood is iteratively updated until it potentially converges to a unimodal probability density function. The time to converge to a unimodal position hypothesis depends on the number of lights detected and the asymmetries/irregularities of the spatial distribution of lights. The proposed LM method does not require any intensity illumination calibration, just the pre-storage of the position and size of all lights in a building, irrespective of their current on/off state. This paper presents a detailed description of the light-matching concept, the implementation details of the LM-assisted PDR fusion scheme using a particle filter, and several simulated and experimental tests, using a light sensor-equipped Galaxy S3 smartphone and an external foot-mounted inertial sensor. The evaluation includes the LM-assisted PDR approach as well as the fusion with other signals of opportunity (WiFi, RFID, Magnetometers or Map-matching) in order to compare their contribution in obtaining high accuracy indoor localization. The integrated solution achieves a localization error lower than 1 m in most of the cases. PMID:24394599

  17. Improving inertial Pedestrian Dead-Reckoning by detecting unmodified switched-on lamps in buildings.

    PubMed

    Jiménez, Antonio R; Zampella, Francisco; Seco, Fernando

    2014-01-01

    This paper explores how inertial Pedestrian Dead-Reckoning (PDR) location systems can be improved with the use of a light sensor to measure the illumination gradients created when a person walks under ceiling-mounted unmodified indoor lights. The process of updating the inertial PDR estimates with the information provided by light detections is a new concept that we have named Light-matching (LM). The displacement and orientation change of a person obtained by inertial PDR is used by the LM method to accurately propagate the location hypothesis, and vice versa; the LM approach benefits the PDR approach by obtaining an absolute localization and reducing the PDR-alone drift. Even from an initially unknown location and orientation, whenever the person passes below a switched-on light spot, the location likelihood is iteratively updated until it potentially converges to a unimodal probability density function. The time to converge to a unimodal position hypothesis depends on the number of lights detected and the asymmetries/irregularities of the spatial distribution of lights. The proposed LM method does not require any intensity illumination calibration, just the pre-storage of the position and size of all lights in a building, irrespective of their current on/off state. This paper presents a detailed description of the light-matching concept, the implementation details of the LM-assisted PDR fusion scheme using a particle filter, and several simulated and experimental tests, using a light sensor-equipped Galaxy S3 smartphone and an external foot-mounted inertial sensor. The evaluation includes the LM-assisted PDR approach as well as the fusion with other signals of opportunity (WiFi, RFID, Magnetometers or Map-matching) in order to compare their contribution in obtaining high accuracy indoor localization. The integrated solution achieves a localization error lower than 1 m in most of the cases. PMID:24394599

  18. Temperature-stable lithium niobate electro-optic Q-switch for improved cold performance

    NASA Astrophysics Data System (ADS)

    Jundt, Dieter H.

    2014-10-01

    Lithium niobate (LN) is commonly used as an electro optic (EO) Q-switch material in infrared targeting lasers because of its relatively low voltage requirements and low cost compared to other crystals. A common challenge is maintaining good performance at the sub-freezing temperatures often experienced during flight. Dropping to low temperature causes a pyro-electric charge buildup on the optical faces that leads to birefringence non-uniformity and depolarization resulting in poor hold-off and premature lasing. The most common solution has been to use radioactive americium to ionize the air around the crystal and bleed off the charge, but the radioactive material requires handling and disposal procedures that can be problematic. We have developed a superior solution that is now being implemented by multiple defense system suppliers. By applying a low level thermo-chemical reduction to the LN crystal optical faces we induce a small conductivity that allows pyro-charges to dissipate. As the material gets more heavily treated, the capacity to dissipate charges improves, but the corresponding optical absorption also increases, causing insertion loss. Even though typical high gain targeting laser systems can tolerate a few percent of added loss, the thermo-chemical processing needs to be carefully optimized. We describe the results of our process optimization to minimize the insertion loss while still giving effective charge dissipation. Treatment is performed at temperatures below 500°C and a conductivity layer less than 0.5mm in depth is created that is uniform across the optical aperture. Because the conductivity is thermally activated, the charge dissipation is less effective at low temperature, and characterization needs to be performed at cold temperatures. The trade-off between optical insertion loss and potential depolarization due to low temperature operation is discussed and experimental results on the temperature dependence of the dissipation time and the

  19. Performance improvements of MOEMS-based diffractive arrays: address isolation and optical switching

    NASA Astrophysics Data System (ADS)

    Panaman, Ganesh; Madison, Seth; Sano, Michael; Castracane, James

    2005-01-01

    Micro-Opto-Electro-Mechanical Systems (MOEMS) have found a variety of applications in fields such as telecommunications, spectroscopy and display technology. MOEMS-based optical switching is currently under investigation for the increased flexibility that such devices provide for reconfiguration of the I/O network for inter-chip communication applications. This potential not only adds an additional degree of freedom for adjustment of transmitter/receiver links but also allows for fine alignment of individual channels in the network link. Further, this use of diffractive arrays for specific applications combines beam steering/adjustment capabilities with the inherent wavelength dependence of the diffractive approach for channel separation and de-multiplexing. Research and development has been concentrated on the progression from single MOEMS components to parallel arrays integrated with optical source arrays for a successful feasibility demonstration. Successful development of such an approach will have a major impact of the next generation communication protocols. This paper will focus on the current status of the MOEMS research program for Free Space Optical inter-chip communication at the College of NanoScale Science and Engineering, University at Albany-SUNY (CNSE). New versions of diffractive arrays stemming from the basic MEMS Compound Grating (MCG; patent #5,999,319) have been produced through various fabrication methods including the MUMPs process1. Most MEMS components relying on electrostatic actuation tend to require high actuation voltages (>20V) compared to the typical 5V levels prevalent in conventional integrated circuits. The specific goal is to yield improved performance while minimizing the power consumption of the components. Structural modifications through the variation in the ruling/electrode spacing distance and array wiring layout through individually addressable gratings have been studied to understand effects on the actuation voltage and

  20. A Dual Triangle Timing Circuit for Improved Performance of 4-Quadrant H-Bridge Switches

    SciTech Connect

    Krafczyk, G.; Jensen, C.; Pfeffer, H.; Warchol, G.; /Fermilab

    2009-05-01

    Fermilab is in the process of upgrading its Booster Correction Element System to include full field correction element magnets to correct position and chromaticity throughout the booster cycle. This upgrade requires power supplies with maximum outputs of {+-}180V/{+-}65A, with current bandwidths of 5k Hz and with slew rates of min to max current in 1ms. For seamless operation around zero current and voltage, we use continuous switching on both sides of the bridge. Although the straightforward way of coordinating the switching on both sides of the bridge can be accomplished with one triangle timing wave and one voltage reference, we have found that using two triangle waves yields a switching coordination that effectively doubles the frequency of the differential ripple on the load and allows for better filtering of the output ripple.

  1. Pretreatment methods to improve nerve immunostaining in corneas from long-term fixed embryonic quail eyes

    NASA Technical Reports Server (NTRS)

    Barrett, J. E.; Wells, D. C.; Conrad, G. W.

    1999-01-01

    Pretreatment methods were used to improve neurofilament immunostaining in corneas from embryonic day 16 Japanese quail corneas that had been stored in fixative solution for several months. A sequential combination of the following three pretreatments: brief microwave heating in saline, followed by extraction with sodium dodecyl sulfate (SDS) at 37 degrees C, followed by digestion with hyaluronidase at 37 degrees C, produced significantly increased antibody staining of corneal neurofilament proteins, compared with embryonic corneas subjected to no prior pretreatments or to single or two-step protocols. After applying the sequence of all three pretreatments, darkest nerve staining and increased numbers of fine branches were observed, together with lower background staining. Thus, the result of applying the three-step pretreatment sequence is better than that of applying any of its component single pretreatments or even combinations of any two of them. These findings therefore suggest that each of these three pretreatments causes a unique effect, beneficial to immunostaining of neurofilament proteins, and that their individual effects are independent and additive. In addition to embryonic corneas, the three-step procedure also may be useful for immunostaining of nerves in other very delicate, highly-hydrated tissues containing an abundance of extracellular matrix.

  2. Adjusting for treatment switching in the METRIC study shows further improved overall survival with trametinib compared with chemotherapy.

    PubMed

    Latimer, Nicholas R; Bell, Helen; Abrams, Keith R; Amonkar, Mayur M; Casey, Michelle

    2016-05-01

    Trametinib, a selective inhibitor of mitogen-activated protein kinase kinase 1 (MEK1) and MEK2, significantly improves progression-free survival compared with chemotherapy in patients with BRAF V600E/K mutation-positive advanced or metastatic melanoma (MM). However, the pivotal clinical trial permitted randomized chemotherapy control group patients to switch to trametinib after disease progression, which confounded estimates of the overall survival (OS) advantage of trametinib. Our purpose was to estimate the switching-adjusted treatment effect of trametinib for OS and assess the suitability of each adjustment method in the primary efficacy population. Of the patients randomized to chemotherapy, 67.4% switched to trametinib. We applied the rank-preserving structural failure time model, inverse probability of censoring weights, and a two-stage accelerated failure time model to obtain estimates of the relative treatment effect adjusted for switching. The intent-to-treat (ITT) analysis estimated a 28% reduction in the hazard of death with trametinib treatment (hazard ratio [HR], 0.72; 95% CI, 0.52-0.98) for patients in the primary efficacy population (data cut May 20, 2013). Adjustment analyses deemed plausible provided OS HR point estimates ranging from 0.48 to 0.53. Similar reductions in the HR were estimated for the first-line metastatic subgroup. Treatment with trametinib, compared with chemotherapy, significantly reduced the risk of death and risk of disease progression in patients with BRAF V600E/K mutation-positive advanced melanoma or MM. Adjusting for switching resulted in lower HRs than those obtained from standard ITT analyses. However, CI are wide and results are sensitive to the assumptions associated with each adjustment method. PMID:27172483

  3. A Switching-Mode Power Supply Design Tool to Improve Learning in a Power Electronics Course

    ERIC Educational Resources Information Center

    Miaja, P. F.; Lamar, D. G.; de Azpeitia, M.; Rodriguez, A.; Rodriguez, M.; Hernando, M. M.

    2011-01-01

    The static design of ac/dc and dc/dc switching-mode power supplies (SMPS) relies on a simple but repetitive process. Although specific spreadsheets, available in various computer-aided design (CAD) programs, are widely used, they are difficult to use in educational applications. In this paper, a graphic tool programmed in MATLAB is presented,…

  4. An Improved Algorithm for Linear Inequalities in Pattern Recognition and Switching Theory.

    ERIC Educational Resources Information Center

    Geary, Leo C.

    This thesis presents a new iterative algorithm for solving an n by l solution vector w, if one exists, to a set of linear inequalities, A w greater than zero which arises in pattern recognition and switching theory. The algorithm is an extension of the Ho-Kashyap algorithm, utilizing the gradient descent procedure to minimize a criterion function…

  5. A Passive Cavity Concept for Improving the Off-Design Performance of Fixed-Geometry Exhaust Nozzles

    NASA Technical Reports Server (NTRS)

    Asbury, Scott C.; Gunther, Christopher L.; Hunter, Craig A.

    1996-01-01

    An investigation was conducted in the model preparation area of the Langley 16-Foot Transonic Tunnel to study a passive cavity concept for improving the off-design performance of fixed-geometry exhaust nozzles. Passive cavity ventilation (through a porous surface) was applied to divergent flap surfaces and tested at static conditions in a sub-scale, nonaxisymmetric, convergent-divergent nozzle. As part of a comprehensive investigation, force, moment and pressure measurements were taken and focusing schlieren flow visualization was obtained for a baseline configuration and D passive cavity configurations. All tests were conducted with no external flow and high-pressure air was used to simulate jet-exhaust flow at nozzle pressure ratios from 1.25 to approximately 9.50. Results indicate that baseline nozzle performance was dominated by unstable shock-induced boundary-layer separation at off-design conditions, which came about through the natural tendency of overexpanded exhaust flow to satisfy conservation requirements by detaching from the nozzle divergent flaps. Passive cavity ventilation added the ability to control off-design separation in the nozzle by either alleviating separation or encouraging stable separation of the exhaust flow. Separation alleviation offers potential for installed nozzle performance benefits by reducing drag at forward flight speeds, even though it may reduce off-design static thrust efficiency as much as 3.2 percent. Encouraging stable separation of the exhaust flow offers significant performance improvements at static, low NPR and low Mach number flight conditions by improving off-design static thrust efficiency as much as 2.8 percent. By designing a fixed-geometry nozzle with fully porous divergent flaps, where both cavity location and percent open porosity of the flaps could be varied, passive flow control would make it possible to improve off-design nozzle performance across a wide operating range. In addition, the ability to

  6. Smart Superstructures with Ultrahigh pH-Sensitivity for Targeting Acidic Tumor Microenvironment: Instantaneous Size Switching and Improved Tumor Penetration.

    PubMed

    Li, Hong-Jun; Du, Jin-Zhi; Liu, Jing; Du, Xiao-Jiao; Shen, Song; Zhu, Yan-Hua; Wang, Xiaoyan; Ye, Xiaodong; Nie, Shuming; Wang, Jun

    2016-07-26

    The currently low delivery efficiency and limited tumor penetration of nanoparticles remain two major challenges of cancer nanomedicine. Here, we report a class of pH-responsive nanoparticle superstructures with ultrasensitive size switching in the acidic tumor microenvironment for improved tumor penetration and effective in vivo drug delivery. The superstructures were constructed from amphiphilic polymer directed assembly of platinum-prodrug conjugated polyamidoamine (PAMAM) dendrimers, in which the amphiphilic polymer contains ionizable tertiary amine groups for rapid pH-responsiveness. These superstructures had an initial size of ∼80 nm at neutral pH (e.g., in blood circulation), but once deposited in the slightly acidic tumor microenvironment (pH ∼6.5-7.0), they underwent a dramatic and sharp size transition within a very narrow range of acidity (less than 0.1-0.2 pH units) and dissociated instantaneously into the dendrimer building blocks (less than 10 nm in diameter). This rapid size-switching feature not only can facilitate nanoparticle extravasation and accumulation via the enhanced permeability and retention effect but also allows faster nanoparticle diffusion and more efficient tumor penetration. We have further carried out comparative studies of pH-sensitive and insensitive nanostructures with similar size, surface charge, and chemical composition in both multicellular spheroids and poorly permeable BxPC-3 pancreatic tumor models, whose results demonstrate that the pH-triggered size switching is a viable strategy for improving drug penetration and therapeutic efficacy. PMID:27244096

  7. Improvement of plant growth and seed yield in Jatropha curcas by a novel nitrogen-fixing root associated Enterobacter species

    PubMed Central

    2013-01-01

    Background Jatropha curcas L. is an oil seed producing non-leguminous tropical shrub that has good potential to be a fuel plant that can be cultivated on marginal land. Due to the low nutrient content of the targeted plantation area, the requirement for fertilizer is expected to be higher than other plants. This factor severely affects the commercial viability of J. curcas. Results We explored the feasibility to use endophytic nitrogen-fixing bacteria that are native to J. curcas to improve plant growth, biomass and seed productivity. We demonstrated that a novel N-fixing endophyte, Enterobacter sp. R4-368, was able to colonize in root and stem tissues and significantly promoted early plant growth and seed productivity of J. curcas in sterilized and non-sterilized soil. Inoculation of young seedling led to an approximately 57.2% increase in seedling vigour over a six week period. At 90 days after planting, inoculated plants showed an average increase of 25.3%, 77.7%, 27.5%, 45.8% in plant height, leaf number, chlorophyll content and stem volume, respectively. Notably, inoculation of the strain led to a 49.0% increase in the average seed number per plant and 20% increase in the average single seed weight when plants were maintained for 1.5 years in non-sterilized soil in pots in the open air. Enterobacter sp. R4-368 cells were able to colonize root tissues and moved systemically to stem tissues. However, no bacteria were found in leaves. Promotion of plant growth and leaf nitrogen content by the strain was partially lost in nifH, nifD, nifK knockout mutants, suggesting the presence of other growth promoting factors that are associated with this bacterium strain. Conclusion Our results showed that Enterobacter sp. R4-368 significantly promoted growth and seed yield of J. curcas. The application of the strains is likely to significantly improve the commercial viability of J. curcas due to the reduced fertilizer cost and improved oil yield. PMID:24083555

  8. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  9. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  10. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  11. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  12. 49 CFR 218.103 - Hand-operated switches, including crossover switches.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Hand-operated switches, including crossover... Equipment, Switches, and Fixed Derails § 218.103 Hand-operated switches, including crossover switches. (a)(1...) General. Employees operating or verifying the position of a hand-operated switch shall: (1) Conduct...

  13. Tetramethoxy-Aminorhodamine (TMARh): A Bichromophore, an Improved Fluorophore, and a pH Switch.

    PubMed

    Sørensen, Thomas Just; Shi, Dong; Laursen, Bo W

    2016-05-17

    Rhodamine is one of the most widely used fluorescent dyes. Here, a new synthetic pathway to the popular dyes is reported and the effect of adding four methoxy groups to the molecular structure is investigated. Tetramethoxy-aminorhodamine (TMARh) is found to show superior pH switching compared to the rhodamine without the four methoxy groups, owing to changed properties of the dark "off" state and increased fluorescence intensity in the protonated "on" state. PMID:26995766

  14. Verbal to visual code switching improves working memory in older adults: an fMRI study

    PubMed Central

    Osaka, Mariko; Otsuka, Yuki; Osaka, Naoyuki

    2012-01-01

    The effect of verbal to visual code switching training on working memory performance was investigated in individuals aged 63 and older. During verbal working memory task performance, the training group (n = 25) was introduced to a verbal to visual code switching strategy while the control group (n = 25) was not exposed to such a strategy. Working memory recognition accuracy was enhanced only in the training group. To explore the neural substrates underlying these strategy effects, fMRI was used to measure brain activity in both groups during working memory task performance before and after an attention training period. In a comparison between pre- and post-training sessions, results showed increased activation in the anterior cingulate cortex (ACC). Relative to the control group, the post-training group exhibited increased activation in the left and right inferior parietal lobules (IPLs) and right superior parietal lobule (SPL). These findings suggest that use of a verbal to visual code switching strategy may assist older individuals in the maintenance of information in working memory. PMID:22363281

  15. Improved operation of a microwave pulse compressor with a laser-triggered high-pressure gas plasma switch

    NASA Astrophysics Data System (ADS)

    Shlapakovski, A.; Gorev, S.; Krasik, Ya. E.

    2016-08-01

    The influence of laser beam parameters on the output pulses of a resonant microwave compressor with a laser-triggered plasma switch was investigated. The S-band compressor, consisting of a rectangular waveguide-based cavity and H-plane waveguide tee with a shorted side arm, was filled with pressurized dry air and pumped by 1.8-μs-long microwave pulses of up to 450 kW power. A Nd:YAG laser was used to ignite the gas discharge in the tee side arm for output pulse extraction. The laser beam (at 213 nm or 532 nm) was directed along the RF electric field lines. It was found that the compressor operated most effectively when the laser beam was focused at the center of the switch waveguide cross-section. In this case, the power extraction efficiency reached ˜47% at an output power of ˜14 MW, while when the laser beam was not focused the maximal extraction efficiency was only ˜20% at ˜6 MW output power. Focusing the laser beam resulted also in a dramatic decrease (down to <1 ns) in the delay of the output pulses' appearance with respect to the time of the beam's entrance into the switch, and the jitter of the output pulses' appearance was minimized. In addition, the quality of the output pulses' waveform was significantly improved.

  16. Improvement of lipid profiles when switching from efavirenz to rilpivirine in HIV-infected patients with dyslipidemia.

    PubMed

    Thamrongwonglert, Pornpimol; Chetchotisakd, Ploenchan; Anunnatsiri, Siriluck; Mootsikapun, Piroon

    2016-02-01

    Rilpivirine (RPV) is a non-nucleoside reverse transcriptase inhibitor, which has better lipid profiles than efavirenz (EFV) in treatment naïve patients. However, the data on treatment experience are limited especially in dyslipidemic HIV patients; thus, we aimed to assess the change of lipid profiles after switching from EFV to RPV in these patients. In this prospective, open-label, cohort study, we enrolled HIV-1 infected adults who had received at least 6 months of EFV-based regimen, with HIV RNA <50 copies/mL for ≥6 months prior to switching. The objectives of this study were to analyze lipid changes and to evaluate the efficacy, safety, tolerability at 24 weeks after switching therapy. Fifty-three patients were enrolled and completed the study. At week 24, a significant decrease in the mean (95% confident interval, CI) total cholesterol (-28.06 mg/dL, 95%CI -35.20 to -20.91, p < 0.0001), LDL-cholesterol (-20.96 mg/dL, 95%CI -28.12 to -13.80, p < 0.0001), high-density lipoprotein (HDL)-cholesterol (-5.11 mg/dL, 95%CI -7.79 to -2.44, p < 0.0001), and triglyceride (-29.79 mg/dL. 95%CI -52.39 to -7.19, p = 0.011) levels were observed. One patient had virologic rebound with HIV RNA of 114 copies/mL at week 24. Three (5.7%) patients had grade 2 elevations of liver enzymes. None of the patients discontinued RPV during the study. Switching from EFV-based therapy to RPV-based regimen improved lipid profiles in fully suppressed HIV patients with dyslipidemia. This treatment should be considered in these patients. PMID:26739573

  17. Study on Thrust Improvement and Ripple Suppression of HTS Linear Switched Reluctance Motor with Coreless HTS Excitation Windings

    NASA Astrophysics Data System (ADS)

    Oto, Satoshi; Hirayama, Tadashi; Kawabata, Shuma

    This paper describes a linear switched reluctance motor (LSRM) in which HTS tapes are used for coreless excitation windings in order to reduce the thrust ripple and normal force. This LSRM consists of a mover with saliency structure, coreless HTS coils and a stator back yoke. In this paper, we first describe the operating principle of the HTS-LSRM. Next, we calculate performances of the HTS-LSRM using 3-D FEM analysis. The effects of the motor structure on the thrust characteristic and normal force characteristics are clarified from the numerical results. Furthermore, we investigate the motor structure for thrust improvement, thrust ripple and normal force reduction.

  18. Modeling and Performance Analysis of an Improved Movement-Based Location Management Scheme for Packet-Switched Mobile Communication Systems

    PubMed Central

    Chung, Yun Won; Park, Suwon

    2014-01-01

    One of the key technologies to support mobility of mobile station (MS) in mobile communication systems is location management which consists of location update and paging. In this paper, an improved movement-based location management scheme with two movement thresholds is proposed, considering bursty data traffic characteristics of packet-switched (PS) services. The analytical modeling for location update and paging signaling loads of the proposed scheme is developed thoroughly and the performance of the proposed scheme is compared with that of the conventional scheme. We show that the proposed scheme outperforms the conventional scheme in terms of total signaling load with an appropriate selection of movement thresholds. PMID:24741363

  19. Using carbon quantum dots to improve the resistive switching behavior of ZnO nanorods device

    NASA Astrophysics Data System (ADS)

    Wang, Xueliang; Xu, Jianping; Shi, Shaobo; Zhang, Xiaosong; Zhang, Xuguang; Shi, Xin; Li, Shubin; Li, Linlin; Liu, Xiaojuan; Li, Lan

    2016-01-01

    An electronic bistable device with a composite structure was fabricated using tapered ZnO nanorod arrays (ZnO NRs) coated with carbon quantum-dots (C QDs). With the addition of C QDs, the ON/OFF resistance ratio is 6 ×102, over 100 times higher than that of device with pristine ZnO NRs. The effect of C QDs on the resistive switching behavior was investigated by current-voltage (I-V) and capacitance-voltage (C-V) characterization. The conduction mechanisms of the devices were discussed using space charge limited current (SCLC) model.

  20. Fault tolerant control for switching discrete-time systems with delays: an improved cone complementarity approach

    NASA Astrophysics Data System (ADS)

    Benzaouia, Abdellah; Ouladsine, Mustapha; Ananou, Bouchra

    2014-10-01

    In this paper, fault tolerant control problem for discrete-time switching systems with delay is studied. Sufficient conditions of building an observer are obtained by using multiple Lyapunov function. These conditions are worked out in a new way, using cone complementarity technique, to obtain new LMIs with slack variables and multiple weighted residual matrices. The obtained results are applied on a numerical example showing fault detection, localisation of fault and reconfiguration of the control to maintain asymptotic stability even in the presence of a permanent sensor fault.

  1. Improved polyacrylamide-based artificial sputum with formalin-fixed tubercle bacilli for training of tuberculosis microscopists.

    PubMed

    Yamada, Hiroyuki; Mitarai, Satoshi; Wahyunitisari, Manik Rento; Mertaniasih, Ni Made; Sugamoto, Tetsuhiro; Chikamatsu, Kinuyo; Aono, Akio; Matsumoto, Hiroko; Fujiki, Akiko

    2011-10-01

    Sputum smear microscopy is an easy, inexpensive, and rapid method for detecting tubercle bacilli when there are more than 10,000 bacilli/ml in the original sputum. Furthermore, because the microscopic method provides not only quantitative, but also qualitative information, such as the shape of bacilli, it has remained significant. We have previously developed and reported panel test slides made from polyacrylamide-based artificial sputum (PBAS) mixed with both cultured THP-1 cells and nonpathogenic mycobacteria. In this paper, we report an improved preparation method for PBAS for panel test slides that provides a simplified method and enhanced availability with high consistency in each grade and in which only negative PBAS is prepared from polyacrylamide and cultured THP-1 cells and mixed with graded formalin-fixed Mycobacterium tuberculosis solution (FFTBS) containing oral flora and Pseudomonas aeruginosa on the slides. In the smears prepared using this improved method, the numbers (average ± standard deviation [SD]) of acid-fast bacilli (AFB) in 300 fields (2- by 3-cm smear) in eight smears of each grade ranged from 5 to 9 (6.4 ± 1.4), from 59 to 88 (74.6 ± 10.0), from 503 to 912 (705.0 ± 145.7), and from 1,819 to 3,256 (2133.3 ± 478.0) in ±, +, ++, and +++ smears, respectively. In addition, this preparation method provided high similarity to the microscopic appearance of bacilli and background seen in the actual patient sputum, with high feasibility. These results revealed that our new PBAS had high authenticity in the appearance and consistency in each grade, which could make it valuable as a reliable artificial sputum for the training of microscopists. PMID:21813720

  2. Improved Polyacrylamide-Based Artificial Sputum with Formalin-Fixed Tubercle Bacilli for Training of Tuberculosis Microscopists▿†

    PubMed Central

    Yamada, Hiroyuki; Mitarai, Satoshi; Wahyunitisari, Manik Rento; Mertaniasih, Ni Made; Sugamoto, Tetsuhiro; Chikamatsu, Kinuyo; Aono, Akio; Matsumoto, Hiroko; Fujiki, Akiko

    2011-01-01

    Sputum smear microscopy is an easy, inexpensive, and rapid method for detecting tubercle bacilli when there are more than 10,000 bacilli/ml in the original sputum. Furthermore, because the microscopic method provides not only quantitative, but also qualitative information, such as the shape of bacilli, it has remained significant. We have previously developed and reported panel test slides made from polyacrylamide-based artificial sputum (PBAS) mixed with both cultured THP-1 cells and nonpathogenic mycobacteria. In this paper, we report an improved preparation method for PBAS for panel test slides that provides a simplified method and enhanced availability with high consistency in each grade and in which only negative PBAS is prepared from polyacrylamide and cultured THP-1 cells and mixed with graded formalin-fixed Mycobacterium tuberculosis solution (FFTBS) containing oral flora and Pseudomonas aeruginosa on the slides. In the smears prepared using this improved method, the numbers (average ± standard deviation [SD]) of acid-fast bacilli (AFB) in 300 fields (2- by 3-cm smear) in eight smears of each grade ranged from 5 to 9 (6.4 ± 1.4), from 59 to 88 (74.6 ± 10.0), from 503 to 912 (705.0 ± 145.7), and from 1,819 to 3,256 (2133.3 ± 478.0) in ±, +, ++, and +++ smears, respectively. In addition, this preparation method provided high similarity to the microscopic appearance of bacilli and background seen in the actual patient sputum, with high feasibility. These results revealed that our new PBAS had high authenticity in the appearance and consistency in each grade, which could make it valuable as a reliable artificial sputum for the training of microscopists. PMID:21813720

  3. Toward efficient aeroelastic energy harvesting: device performance comparisons and improvements through synchronized switching

    NASA Astrophysics Data System (ADS)

    Bryant, Matthew; Schlichting, Alexander D.; Garcia, Ephrahim

    2013-04-01

    This paper presents experimental energy harvesting efficiency analysis of a piezoelectric device driven to limit cycle oscillations by an aeroelastic flutter instability. Wind tunnel testing of the flutter energy harvester was used to measure the power extracted through a matched resistive load as well as the variation in the device swept area over a range of wind speeds. The efficiency of this energy harvester was shown to be maximized at a wind speed of about 2.4 m/s, which corresponds to a limit cycle oscillation (LCO) frequency that matches the first natural frequency of the piezoelectric structure. At this wind speed, the overall system efficiency was 2.6%, which exceeds the peak efficiency of other comparably sized oscillator-based wind energy harvesters using either piezoelectric or electromagnetic transduction. Active synchronized switching techniques are proposed as a method to further increase the overall efficiency of this device by both boosting the electrical output and also reducing the swept area by introducing additional electrical energy dissipation. Real-time peak detection and switch control is the major technical challenge to implementing such active power electronics schemes in a practical system where the wind speed and the corresponding LCO frequency are not generally known or constant. A promising microcontroller (MCU) based peak detector is implemented and tested over a range of operating wind speeds.

  4. Switching photo-stimulated males between groups of goats does not improve the reproductive response during the male effect.

    PubMed

    Loya-Carrera, J; Bedos, M; Ponce-Covarrubias, J L; Hernández, H; Chemineau, P; Keller, M; Delgadillo, J A

    2014-04-01

    We aimed to determine whether the daily exchange of photo-stimulated males among subgroups of females improved the reproductive response of anestrous goats exposed to males. Bucks were rendered sexually active during the rest season by exposure to 2.5 months of long days from November 1st. In April, males (n=3) were put in contact with three subgroups of anestrous goats (one male per 12 females) where they remained throughout the study, constituting the fixed-group. Other males (n=3) were put in contact with three subgroups of females (one male per 11-12 females) and were rotated daily among them, constituting the rotated-group. The sexual behavior of all males was registered from 08:00 to 09:00 on days 0, 1, 2, and 8 after exchanging the males from the subgroups of females. Ovulation and pregnancy rates were determined by transrectal ultrasonography. The occurrences of ano-genital sniffing, nudging (days 1, 2, and 8), and mounting attempts (days 2 and 8) were greater in the rotated than in the fixed-group (P<0.01). The proportions of females that ovulated did not differ among goats from the fixed (92%) and rotated-group (94%; P>0.05). The proportion of pregnant females and the fertility at kidding did not differ between those from the rotated (79% and 59%) and fixed-group (83% and 61%; P>0.05). We conclude that the daily exchange of photo-stimulated males among subgroups induced an increase of their sexual behavior, but does not improve the pregnancy rates in seasonal anestrous goats. PMID:24602505

  5. Improvement of deoxidization efficiency of nitric monoxide by shortening pulse width of semiconductor opening switch pulse power generator

    NASA Astrophysics Data System (ADS)

    Kakuta, Takatoshi; Yagi, Ippei; Takaki, Koichi

    2015-01-01

    The deoxidization efficiency of nitric monoxide (NO) was improved by shortening the pulse width of the voltage applied to a corona reactor. The deoxidization efficiency of NO was evaluated as the NO removal efficiency in nitrogen (N2) gas containing 200 ppm NO. The corona reactor had a coaxial geometry and consisted of center high-voltage wire and outer grounded cylinder electrodes. A nanosecond high-voltage pulse was generated using an inductive energy storage pulse power circuit with a semiconductor opening switch and was applied to the center wire electrode in the corona reactor. Fast recovery diodes were utilized as a semiconductor opening switch. The pulse width of the applied voltage was reduced from 21 to 14 ns with the arrester connected in parallel to the reactor. The energy efficiency for NO removal was improved from 8.2 to 35.7 g kW-1 h-1 with the arrester connected. The pulse width was also reduced to 8 ns by optimizing the circuit parameters. It was confirmed from observation with an intensified charge-coupled device (ICCD) camera that the streamer corona discharge transited to a glowlike discharge after the streamer propagated from the center wire electrode to the outer cylinder electrode. The duration of the glowlike phase was reduced with the arrester connected. The energy consumed in the glowlike phase was also reduced from 15.7 to 4.6 mJ with the arrester connected.

  6. Utilizing multiple state variables to improve the dynamic range of analog switching in a memristor

    NASA Astrophysics Data System (ADS)

    Jeong, YeonJoo; Kim, Sungho; Lu, Wei D.

    2015-10-01

    Memristors and memristive systems have been extensively studied for data storage and computing applications such as neuromorphic systems. To act as synapses in neuromorphic systems, the memristor needs to exhibit analog resistive switching (RS) behavior with incremental conductance change. In this study, we show that the dynamic range of the analog RS behavior can be significantly enhanced in a tantalum-oxide-based memristor. By controlling different state variables enabled by different physical effects during the RS process, the gradual filament expansion stage can be selectively enhanced without strongly affecting the abrupt filament length growth stage. Detailed physics-based modeling further verified the observed experimental effects and revealed the roles of oxygen vacancy drift and diffusion processes, and how the diffusion process can be selectively enhanced during the filament expansion stage. These findings lead to more desirable and reliable memristor behaviors for analog computing applications. Additionally, the ability to selectively control different internal physical processes demonstrated in the current study provides guidance for continued device optimization of memristor devices in general.

  7. Utilizing multiple state variables to improve the dynamic range of analog switching in a memristor

    SciTech Connect

    Jeong, YeonJoo; Kim, Sungho; Lu, Wei D.

    2015-10-26

    Memristors and memristive systems have been extensively studied for data storage and computing applications such as neuromorphic systems. To act as synapses in neuromorphic systems, the memristor needs to exhibit analog resistive switching (RS) behavior with incremental conductance change. In this study, we show that the dynamic range of the analog RS behavior can be significantly enhanced in a tantalum-oxide-based memristor. By controlling different state variables enabled by different physical effects during the RS process, the gradual filament expansion stage can be selectively enhanced without strongly affecting the abrupt filament length growth stage. Detailed physics-based modeling further verified the observed experimental effects and revealed the roles of oxygen vacancy drift and diffusion processes, and how the diffusion process can be selectively enhanced during the filament expansion stage. These findings lead to more desirable and reliable memristor behaviors for analog computing applications. Additionally, the ability to selectively control different internal physical processes demonstrated in the current study provides guidance for continued device optimization of memristor devices in general.

  8. MOSFET solid state switching circuit improves the 0 to 99% rise time for framing camera deflection electronics

    SciTech Connect

    Rivera, A.T.; Thomas, S.

    1996-09-01

    We have improved the 0 to 99% rise time voltage on our 2 frame deflection plates from 160 to 65 nS with the addition of a peaking circuit that works in conjunction with our primary 2 frame deflection circuitry. Our peaking technique has applications to other HV pulsers including those which must drive 51 ohm loads. Generally, rise time voltages are measured between 10 and 90%. To minimize the camera image blur resulting from the dynamic influence of deflection plate potentials acting on photocathode electrons, it was necessary to design a circuit that would rise from 0 to the 99% voltage level in under 100nS. Once this voltage was reached, it was necessary to stay within 1% of the attained voltage level for a duration of 1 uS. This was accomplished with the use of MOSFET solid state switching.

  9. Correlation between changes in quality of life and symptomatic improvement in Chinese patients switched from typical antipsychotics to olanzapine

    PubMed Central

    Montgomery, William; Kadziola, Zbigniew; Ye, Wenye; Xue, Hai Bo; Liu, Li; Treuer, Tamás

    2015-01-01

    Purpose The aim of this study was to investigate the correlation between changes in symptoms and changes in self-reported quality of life among Chinese patients with schizophrenia who were switched from a typical antipsychotic to olanzapine during usual outpatient care. Patients and methods This post hoc analysis was conducted using data from the Chinese subgroup (n=475) of a multicountry, 12-month, prospective, noninterventional, observational study. The primary publication previously reported the efficacy, safety, and quality of life among patients who switched from a typical antipsychotic to olanzapine. Patients with schizophrenia were included if their symptoms were inadequately controlled with a typical antipsychotic and they were switched to olanzapine. Symptom severity was measured using the Brief Psychiatric Rating Scale (BPRS) and the Clinical Global Impressions-Severity scale (CGI-S). Health-Related Quality of Life (HRQOL) was assessed using the World Health Organization Quality of Life–Abbreviated (WHOQOL-BREF). Paired t-tests were performed to assess changes from baseline to endpoint. Pearson’s correlation coefficients (r) were used to assess the correlations between change in symptoms (BPRS and CGI-S scores) and change in HRQOL (WHOQOL-BREF scores). Results Symptoms and HRQOL both improved significantly over the 12 months of treatment (P<0.001). Significant correlations were observed between changes from baseline to end of study on the BPRS and the CGI-S and each of the WHOQOL-BREF four domain scores and two overall quality-of-life questions. The correlation coefficients ranged from r=−0.45 to r=−0.53 for the BPRS and WHOQOL-BREF. The correlation coefficients were slightly smaller between the CGI-S and WHOQOL-BREF, ranging from r=−0.33 to r=−0.40. Conclusion For patients with schizophrenia, assessing quality of life has the potential to add valuable information to the clinical assessment that takes into account the patient’s own

  10. Multiserver switch scheduling for high speed optical switches

    NASA Astrophysics Data System (ADS)

    Golla, Prasad; Blanton, John; Damm, Gerard

    2003-10-01

    A switch matrix implemented as an optical crossbar using semiconductor optical amplifiers is able to accommodate extreme concentrations of data traffic. Due to the need to reduce optical guard band overhead it is beneficial to switch fixed size bursts of data cells on a time slot basis. The high capacity of the optical matrix supports multiple optical ports per burst card, and the implementation of multiple queue servers per burst card helps make better use of the multiplicity of ports. Problems associated with arbitrating multiple ports and multiple servers per burst card have been resolved by extending the operation of existing iterative, single server scheduling algorithms. The multiserver arbitration time will be in proportion to the number of servers -- corresponding to the channels of DWDM link -- unless a reconciliation stage is used after each iteration when an arbiter per server is used. The reconciliation stage sets the problem of broken data dependencies between server arbitrations in this case. Further, to address the time limitations for computing the scheduling solution, parallel arbiter implementations have been developed and tested against single arbiter designs. Again, the broken dependencies between iterations of an arbitration are addressed through the use of a grant reconciliation stage. The use of multiple queue servers per burst card also resolves some of the data loss problems related to polarized traffic. Simulations of the multiple server and parallel arbiter implementations have demonstrated their efficiency compared to previous implementations. Compounded to this problem is maintaining high throughput of the switch matrix while observing data transit time limits. This involves balancing two contradictory requirements; switch or line card efficiency and data transit times. To improve efficiency it is desirable to transmit only full packets. However, to prevent loss of data due to timeout it will be necessary to transmit some incomplete

  11. Akt inhibition improves irinotecan treatment and prevents cell emergence by switching the senescence response to apoptosis

    PubMed Central

    Vétillard, Alexandra; Jonchère, Barbara; Moreau, Marie; Toutain, Bertrand; Henry, Cécile; Fontanel, Simon; Bernard, Anne-Charlotte; Campone, Mario; Guette, Catherine; Coqueret, Olivier

    2015-01-01

    Activated in response to chemotherapy, senescence is a tumor suppressive mechanism that induces a permanent loss of proliferation. However, in response to treatment, it is not really known how cells can escape senescence and how irreversible or incomplete this pathway is. We have recently described that cells that escape senescence are more transformed than non-treated parental cells, they resist anoikis and rely on Mcl-1. In this study, we further characterize this emergence in response to irinotecan, a first line treatment used in colorectal cancer. Our results indicate that Akt was activated as a feedback pathway during the early step of senescence. The inhibition of the kinase prevented cell emergence and improved treatment efficacy, both in vitro and in vivo. This improvement was correlated with senescence inhibition, p21waf1 downregulation and a concomitant activation of apoptosis due to Noxa upregulation and Mcl-1 inactivation. The inactivation of Noxa prevented apoptosis and increased the number of emergent cells. Using either RNA interference or p21waf1-deficient cells, we further confirmed that an intact p53-p21-senescence pathway favored cell emergence and that its downregulation improved treatment efficacy through apoptosis induction. Therefore, although senescence is an efficient suppressive mechanism, it also generates more aggressive cells as a consequence of apoptosis inhibition. We therefore propose that senescence-inducing therapies should be used sequentially with drugs favoring cell death such as Akt inhibitors. This should reduce cell emergence and tumor relapse through a combined induction of senescence and apoptosis. PMID:26485768

  12. Compound semiconductor optical waveguide switch

    DOEpatents

    Spahn, Olga B.; Sullivan, Charles T.; Garcia, Ernest J.

    2003-06-10

    An optical waveguide switch is disclosed which is formed from III-V compound semiconductors and which has a moveable optical waveguide with a cantilevered portion that can be bent laterally by an integral electrostatic actuator to route an optical signal (i.e. light) between the moveable optical waveguide and one of a plurality of fixed optical waveguides. A plurality of optical waveguide switches can be formed on a common substrate and interconnected to form an optical switching network.

  13. Real-time DC-dynamic biasing method for switching time improvement in severely underdamped fringing-field electrostatic MEMS actuators.

    PubMed

    Small, Joshua; Fruehling, Adam; Garg, Anurag; Liu, Xiaoguang; Peroulis, Dimitrios

    2014-01-01

    Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement. PMID:25145811

  14. Real-Time DC-dynamic Biasing Method for Switching Time Improvement in Severely Underdamped Fringing-field Electrostatic MEMS Actuators

    PubMed Central

    Small, Joshua; Fruehling, Adam; Garg, Anurag; Liu, Xiaoguang; Peroulis, Dimitrios

    2014-01-01

    Mechanically underdamped electrostatic fringing-field MEMS actuators are well known for their fast switching operation in response to a unit step input bias voltage. However, the tradeoff for the improved switching performance is a relatively long settling time to reach each gap height in response to various applied voltages. Transient applied bias waveforms are employed to facilitate reduced switching times for electrostatic fringing-field MEMS actuators with high mechanical quality factors. Removing the underlying substrate of the fringing-field actuator creates the low mechanical damping environment necessary to effectively test the concept. The removal of the underlying substrate also a has substantial improvement on the reliability performance of the device in regards to failure due to stiction. Although DC-dynamic biasing is useful in improving settling time, the required slew rates for typical MEMS devices may place aggressive requirements on the charge pumps for fully-integrated on-chip designs. Additionally, there may be challenges integrating the substrate removal step into the back-end-of-line commercial CMOS processing steps. Experimental validation of fabricated actuators demonstrates an improvement of 50x in switching time when compared to conventional step biasing results. Compared to theoretical calculations, the experimental results are in good agreement. PMID:25145811

  15. Study of optoelectronic switch for satellite-switched time-division multiple access

    NASA Technical Reports Server (NTRS)

    Su, Shing-Fong; Jou, Liz; Lenart, Joe

    1987-01-01

    The use of optoelectronic switching for satellite switched time division multiple access will improve the isolation and reduce the crosstalk of an IF switch matrix. The results are presented of a study on optoelectronic switching. Tasks include literature search, system requirements study, candidate switching architecture analysis, and switch model optimization. The results show that the power divided and crossbar switching architectures are good candidates for an IF switch matrix.

  16. Nonblocking optical planar switching matrices of short length

    NASA Astrophysics Data System (ADS)

    Giglmayr, Josef

    2001-05-01

    Planar switching matrices of parallel waveguides (WGs) have reduced loss due to the absence of tapering but require some confinement of wave propagation reported from Kerr nonlinearities (NL). Parallel switching matrices are fed by the multiple splitting of the input WGs, an appropriate network model is the parallel version of the Spanke-Benes (PSB) network and the reduction of the number of stages (NSs) below N (for N i/o) is analyzed. However, in the parallel case, regarding WGs and SB networks, the location of switches can no longer be fixed but must be a moving location (ML). From the several parallel paths through the PSB network the shortest path is chosen either at the end by path selection switches (PS-SWs) or at the beginning of the switching matrix, respectively. It turns out that the reduction of NS of the switching matrix and in turn the saving of the number of switches (NSWs) is compensated by the number of PS-SWs at the end or at the beginning of the matrix. The replacement of the PS-SWs by combiners at the output (i) restores the energy balance but (ii) causes phase mismatch (iii) provides redundant paths (iv) restricts the overall NS to the NS of the SB network for each copy but (v) improves the nonblocking (NB) characteristic. The routing of the switching matrices and their optical implementation is also briefly discussed.

  17. An analysis on how switching to a more balanced and naturally improved milk would affect consumer health and the environment.

    PubMed

    Roibás, Laura; Martínez, Ismael; Goris, Alfonso; Barreiro, Rocío; Hospido, Almudena

    2016-10-01

    This study compares a premium brand of UHT milk, Unicla, characterised by an improved nutritional composition, to conventional milk, in terms of health effects and environmental impacts. Unlike enriched milks, in which nutrients are added to the final product, Unicla is obtained naturally by improving the diet of the dairy cows. Health effects have been analysed based on literature findings, while the environmental analysis focused on those spheres of the environment where milk is expected to cause the higher impacts, and thus carbon (CF) and water footprints (WF) have been determined. Five final products have been compared: 3 conventional (skimmed, semi-skimmed, whole) and 2 Unicla (skimmed, semi-skimmed) milks. As a functional unit, one litre of packaged UHT milk entering the regional distribution centre has been chosen. The improved composition of Unicla milk is expected to decrease the risk of cardiovascular disease and to protect consumers against oxidative damage, among other health benefits. Concerning the environmental aspect, CF of Unicla products are, on average, 10% lower than their conventional equivalents, mainly due to the lower enteric emissions of caused by the Unicla diet. No significant differences were found between the WF of Unicla and conventional milk. Raw milk is the main contributor to both footprints (on average, 83.2 and 84.3% of the total CF of Unicla and conventional milk, respectively, and 99.9% of WF). The results have been compared to those found in literature, and a sensitivity analysis has been performed to verify their robustness. The study concludes that switching to healthier milk compositions can help slowing down global warming, without contributing to other environmental issues such as water scarcity. The results should encourage other milk companies to commit to the development of healthier, less environmentally damaging products, and also to stimulate consumers to bet on them. PMID:27239712

  18. Improvement of Bipolar Switching Properties of Gd:SiOx RRAM Devices on Indium Tin Oxide Electrode by Low-Temperature Supercritical CO2 Treatment

    NASA Astrophysics Data System (ADS)

    Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M.

    2016-02-01

    Bipolar switching resistance behaviors of the Gd:SiO2 resistive random access memory (RRAM) devices on indium tin oxide electrode by the low-temperature supercritical CO2-treated technology were investigated. For physical and electrical measurement results obtained, the improvement on oxygen qualities, properties of indium tin oxide electrode, and operation current of the Gd:SiO2 RRAM devices were also observed. In addition, the initial metallic filament-forming model analyses and conduction transferred mechanism in switching resistance properties of the RRAM devices were verified and explained. Finally, the electrical reliability and retention properties of the Gd:SiO2 RRAM devices for low-resistance state (LRS)/high-resistance state (HRS) in different switching cycles were also measured for applications in nonvolatile random memory devices.

  19. Improvement of Bipolar Switching Properties of Gd:SiOx RRAM Devices on Indium Tin Oxide Electrode by Low-Temperature Supercritical CO2 Treatment.

    PubMed

    Chen, Kai-Huang; Chang, Kuan-Chang; Chang, Ting-Chang; Tsai, Tsung-Ming; Liang, Shu-Ping; Young, Tai-Fa; Syu, Yong-En; Sze, Simon M

    2016-12-01

    Bipolar switching resistance behaviors of the Gd:SiO2 resistive random access memory (RRAM) devices on indium tin oxide electrode by the low-temperature supercritical CO2-treated technology were investigated. For physical and electrical measurement results obtained, the improvement on oxygen qualities, properties of indium tin oxide electrode, and operation current of the Gd:SiO2 RRAM devices were also observed. In addition, the initial metallic filament-forming model analyses and conduction transferred mechanism in switching resistance properties of the RRAM devices were verified and explained. Finally, the electrical reliability and retention properties of the Gd:SiO2 RRAM devices for low-resistance state (LRS)/high-resistance state (HRS) in different switching cycles were also measured for applications in nonvolatile random memory devices. PMID:26831690

  20. Formation polarity dependent improved resistive switching memory characteristics using nanoscale (1.3 nm) core-shell IrOx nano-dots

    PubMed Central

    2012-01-01

    Improved resistive switching memory characteristics by controlling the formation polarity in an IrOx/Al2O3/IrOx-ND/Al2O3/WOx/W structure have been investigated. High density of 1 × 1013/cm2 and small size of 1.3 nm in diameter of the IrOx nano-dots (NDs) have been observed by high-resolution transmission electron microscopy. The IrOx-NDs, Al2O3, and WOx layers are confirmed by X-ray photo-electron spectroscopy. Capacitance-voltage hysteresis characteristics show higher charge-trapping density in the IrOx-ND memory as compared to the pure Al2O3 devices. This suggests that the IrOx-ND device has more defect sites than that of the pure Al2O3 devices. Stable resistive switching characteristics under positive formation polarity on the IrOx electrode are observed, and the conducting filament is controlled by oxygen ion migration toward the Al2O3/IrOx top electrode interface. The switching mechanism is explained schematically based on our resistive switching parameters. The resistive switching random access memory (ReRAM) devices under positive formation polarity have an applicable resistance ratio of > 10 after extrapolation of 10 years data retention at 85°C and a long read endurance of 105 cycles. A large memory size of > 60 Tbit/sq in. can be realized in future for ReRAM device application. This study is not only important for improving the resistive switching memory performance but also help design other nanoscale high-density nonvolatile memory in future. PMID:22439604

  1. Improving the solubility of anti-LINGO-1 monoclonal antibody Li33 by isotype switching and targeted mutagenesis

    SciTech Connect

    Pepinsky, R. Blake; Silvian, Laura; Berkowitz, Steven A.; Farrington, Graham; Lugovskoy, Alexey; Walus, Lee; Eldredge, John; Capili, Allan; Mi, Sha; Graff, Christilyn; Garber, Ellen

    2010-11-15

    Monoclonal antibodies (Mabs) are a favorite drug platform of the biopharmaceutical industry. Currently, over 20 Mabs have been approved and several hundred others are in clinical trials. The anti-LINGO-1 Mab Li33 was selected from a large panel of antibodies by Fab phage display technology based on its extraordinary biological activity in promoting oligodendrocyte differentiation and myelination in vitro and in animal models of remyelination. However, the Li33 Fab had poor solubility when converted into a full antibody in an immunoglobulin G1 framework. A detailed analysis of the biochemical and structural features of the antibody revealed several possible reasons for its propensity to aggregate. Here, we successfully applied three molecular approaches (isotype switching, targeted mutagenesis of complementarity determining region residues, and glycosylation site insertion mutagenesis) to address the solubility problem. Through these efforts we were able to improve the solubility of the Li33 Mab from 0.3 mg/mL to >50 mg/mL and reduce aggregation to an acceptable level. These strategies can be readily applied to other proteins with solubility issues.

  2. Improved bipolar resistive switching memory characteristics in Ge0.5Se0.5 solid electrolyte by using dispersed silver nanocrystals on bottom electrode.

    PubMed

    Kim, Jang-Han; Nam, Ki-Hyun; Hwang, Inchan; Cho, Won-Ju; Park, Byoungchoo; Chung, Hong-Bay

    2014-12-01

    Resistive switching random-access memory (ReRAM) devices based on chalcogenide solid electrolytes have recently become a promising candidate for future low-power nanoscale nonvolatile memory application. The resistive switching mechanism of ReRAM is based on the formation and rupture of conductive filament (CF) in the chalcogenide solid electrolyte layers. However, the random diffusion of metal ions makes it hard to control the CF formation, which is one of the major obstacles to improving device performance of ReRAM devices. We demonstrate the spin-coated metal nanocrystals (NCs) enhance the bipolar resistive switching (BRS) memory characteristics. Compared to the Ag/Ge0.5Se0.5/Pt structure, excellent resistive switching memory characteristics were obtained from the Ag/Ge0.5Se0.5/Ag NCs/Pt structure. Ag NCs improve the uniformity of resistance values and reduce the reset voltage and current. A stable DC endurance (> 100 cycles) and a high data retention (> 10(4) sec) were achieved by spin coating the Ag NCs on the Pt bottom electrode for ReRAMs. PMID:25971090

  3. Improvement of stability and efficiency in diode-pumped passively Q-switched intracavity optical parametric oscillator with a monolithic cavity Improvement of stability and efficiency

    NASA Astrophysics Data System (ADS)

    Huang, J. Y.; Zhuang, W. Z.; Huang, Y. P.; Huang, Y. J.; Su, K. W.; Chen, Y. F.

    2012-07-01

    We improve the performance of intracavity optical parametric oscillator (IOPO) pumped by a diode-pumped Q-switched Nd:YVO4/Cr4+:YAG laser. The IOPO cavity is formed independently by a monolithic KTP crystal that the mirrors are directly deposited on top of the nonlinear crystal. We study the performances of this IOPO cavity with different reflectivity of the output coupler at 1.5 μm (Rs) of 80 and 50%. The average power of 1.5 μm is up to 3.3 W at the maximum pump power of 16.8 W for both cases. The diode-to-signal conversion efficiency is up to 20%, which is the highest one for IOPOs to our best knowledge. At the maximum pump power, the pulse energies are 41 μJ with the pulse width of 3 ns at a pulse repetition rate (PRR) of 80 kHz for Rs = 80% and 51 μJ with the pulse width of 1.2 ns at a PRR of 65 kHz for Rs = 50%, respectively. The pulse amplitude fluctuations in standard deviation are 2.6% for Rs = 80% and 4% for Rs = 50%, respectively.

  4. Microdisk resonator assisted all-optical switching with improved speed using a reverse-biased p-n diode

    NASA Astrophysics Data System (ADS)

    Xie, Jingya; Zhou, Linjie; Li, Xinwan; Chen, Jianping

    2015-05-01

    We present a compact and power efficient all-optical switching using a silicon microdisk resonator integrated with a p-n junction. We study the dependence of free-carrier lifetime, one of the most critical parameters to determine the switching speed, on reverse bias, optical intensity, and p-n junction position and dimension. Our experiments reveal that the carrier lifetime decreases with the increasing reverse bias, consistent with the theoretical results. The all-optical switching of a 211-1 non-return-to-zero pseudo-random binary sequence (PRBS) signal at a data rate of 10 Gbits/s is demonstrated with p-n junction reversely biased at -15 V and the pump power being 5.96 dBm.

  5. Switch wear leveling

    SciTech Connect

    Wu, Hunter; Sealy, Kylee; Gilchrist, Aaron

    2015-09-01

    An apparatus for switch wear leveling includes a switching module that controls switching for two or more pairs of switches in a switching power converter. The switching module controls switches based on a duty cycle control technique and closes and opens each switch in a switching sequence. The pairs of switches connect to a positive and negative terminal of a DC voltage source. For a first switching sequence a first switch of a pair of switches has a higher switching power loss than a second switch of the pair of switches. The apparatus includes a switch rotation module that changes the switching sequence of the two or more pairs of switches from the first switching sequence to a second switching sequence. The second switch of a pair of switches has a higher switching power loss than the first switch of the pair of switches during the second switching sequence.

  6. Enhancing nitrogen removal efficiency and reducing nitrate liquor recirculation ratio by improving simultaneous nitrification and denitrification in integrated fixed-film activated sludge (IFAS) process.

    PubMed

    Bai, Yang; Zhang, Yaobin; Quan, Xie; Chen, Shuo

    2016-01-01

    An integrated fixed-film activated sludge (IFAS) process (G1) and an activated sludge anoxic-oxic process (G2) were operated at nitrate liquor recirculation ratio (R) of 100, 200 and 300% to investigate the feasibility of enhancing nitrogen removal efficiency (RTN) and reducing R by improving simultaneous nitrification and denitrification (SND) in the IFAS process. The results showed that the effluent NH4(+)-N and total nitrogen (TN) of G1 at R of 200% were less than 1.5 and 14.5 mg/L, satisfying the Chinese discharge standard (NH4(+)-N < 5 mg/L; TN < 15 mg/L). However, the effluent NH4(+)-N and TN of G2 at R of 300% were higher than 8.5 and 15.3 mg/L. It indicated that better RTN could be achieved at a lower R in the IFAS process. The polymerase chain reaction-denaturing gradient gel electrophoresis results implied that nitrifiers and denitrifiers co-existed in one microbial community, facilitating the occurrence of SND in the aerobic reactor of G1, and the contribution of SND to TN removal efficiency ranged 15-19%, which was the main reason that the RTN was improved in the IFAS process. Therefore, the IFAS process was an effective method for improving RTN and reducing R. In practical application, this advantage of the IFAS process can decrease the electricity consumption for nitrate liquor recirculation flow, thereby saving operational costs. PMID:26901725

  7. Improving short-term forecasting during ramp events by means of Regime-Switching Artificial Neural Networks

    NASA Astrophysics Data System (ADS)

    Gallego, C.; Costa, A.; Cuerva, A.

    2010-09-01

    Since nowadays wind energy can't be neither scheduled nor large-scale storaged, wind power forecasting has been useful to minimize the impact of wind fluctuations. In particular, short-term forecasting (characterised by prediction horizons from minutes to a few days) is currently required by energy producers (in a daily electricity market context) and the TSO's (in order to keep the stability/balance of an electrical system). Within the short-term background, time-series based models (i.e., statistical models) have shown a better performance than NWP models for horizons up to few hours. These models try to learn and replicate the dynamic shown by the time series of a certain variable. When considering the power output of wind farms, ramp events are usually observed, being characterized by a large positive gradient in the time series (ramp-up) or negative (ramp-down) during relatively short time periods (few hours). Ramp events may be motivated by many different causes, involving generally several spatial scales, since the large scale (fronts, low pressure systems) up to the local scale (wind turbine shut-down due to high wind speed, yaw misalignment due to fast changes of wind direction). Hence, the output power may show unexpected dynamics during ramp events depending on the underlying processes; consequently, traditional statistical models considering only one dynamic for the hole power time series may be inappropriate. This work proposes a Regime Switching (RS) model based on Artificial Neural Nets (ANN). The RS-ANN model gathers as many ANN's as different dynamics considered (called regimes); a certain ANN is selected so as to predict the output power, depending on the current regime. The current regime is on-line updated based on a gradient criteria, regarding the past two values of the output power. 3 Regimes are established, concerning ramp events: ramp-up, ramp-down and no-ramp regime. In order to assess the skillness of the proposed RS-ANN model, a single

  8. SPARK GAP SWITCH

    DOEpatents

    Neal, R.B.

    1957-12-17

    An improved triggered spark gap switch is described, capable of precisely controllable firing time while switching very large amounts of power. The invention in general comprises three electrodes adjustably spaced and adapted to have a large potential impressed between the outer electrodes. The central electrode includes two separate elements electrically connected togetaer and spaced apart to define a pair of spark gaps between the end electrodes. Means are provided to cause the gas flow in the switch to pass towards the central electrode, through a passage in each separate element, and out an exit disposed between the two separate central electrode elements in order to withdraw ions from the spark gap.

  9. High-speed switching characteristics of integrated optoelectronic crossbar switch

    NASA Astrophysics Data System (ADS)

    Gouin, Francois L.; Almeida, Carlos; Callender, Claire L.; Robitaille, Lucie; Noad, Julian P.

    1999-04-01

    Optoelectronic (OE) switching is a promising approach for routing signals in fiber optic networks. Recently, the integration of a 4 X 4 MSM array with optical surface waveguides has been reported. This technique greatly simplifies the packaging of an OE switch. The on-chip polyimide optical waveguides perform the optical signal distribution to a matrix of MSMs which are responsible for the switching operation itself. Photoresponse bandwidths exceeding 4 GHz have been demonstrated. Another important characteristic of a switch is the switching speed since it determines the reconfiguration time. Mechanical and thermal optical waveguide switches offer switching speeds of the order of milliseconds which is sufficient for network traffic management but too slow for packet switching. We report measurements on the switching characteristics of a 4 X 4 optoelectronic switch performed in both the frequency and time domain. In the time domain, the individual crosspoints exhibit a rise time of 3 ns. However, a sizeable overshoot and ringing settles only after 35 ns. This constitutes the reconfiguration time at present. This is confirmed by measurements in the frequency domain of the electrical transmission from control line to output line. The 3-dB switching bandwidth is a few hundred megahertz. The 35 ns reconfiguration time indicates that it is already suitable for packet switching in a 10 Mb/s network. Switching speed measurements on individual MSMs suggests that modifications to the switch circuit could improve the switching time. The switch could also find application as a component in the wavelength conversion circuit of a WDM fiber optic network.

  10. A Review of NEPA, a Novel Fixed Antiemetic Combination with the Potential for Enhancing Guideline Adherence and Improving Control of Chemotherapy-Induced Nausea and Vomiting.

    PubMed

    Hesketh, Paul J; Aapro, Matti; Jordan, Karin; Schwartzberg, Lee; Bosnjak, Snezana; Rugo, Hope

    2015-01-01

    Combination antiemetic regimens targeting multiple molecular pathways associated with emesis have become the standard of care for prevention of chemotherapy-induced nausea and vomiting (CINV) related to highly and moderately emetogenic chemotherapies. Antiemetic consensus guidelines from several professional societies are widely available and updated regularly as new data emerges. Unfortunately, despite substantial research supporting the notion that guideline conformity improves CINV control, adherence to antiemetic guidelines is unsatisfactory. While studies are needed to identify specific barriers to guideline use and explore measures to enhance adherence, a novel approach has been taken to improve clinician adherence and patient compliance, with the development of a new combination antiemetic. NEPA is an oral fixed combination of a new highly selective NK1 receptor antagonist (RA), netupitant, and the pharmacologically and clinically distinct 5-HT3 RA, palonosetron. This convenient antiemetic combination offers guideline-consistent prophylaxis by targeting two critical pathways associated with CINV in a single oral dose administered only once per cycle. This paper will review and discuss the NEPA data in the context of how this first combination antiemetic may overcome some of the barriers interfering with adherence to antiemetic guidelines, enhance patient compliance, and offer a possible advance in the prevention of CINV for patients. PMID:26421300

  11. A Review of NEPA, a Novel Fixed Antiemetic Combination with the Potential for Enhancing Guideline Adherence and Improving Control of Chemotherapy-Induced Nausea and Vomiting

    PubMed Central

    Hesketh, Paul J.; Aapro, Matti; Jordan, Karin; Schwartzberg, Lee; Bosnjak, Snezana; Rugo, Hope

    2015-01-01

    Combination antiemetic regimens targeting multiple molecular pathways associated with emesis have become the standard of care for prevention of chemotherapy-induced nausea and vomiting (CINV) related to highly and moderately emetogenic chemotherapies. Antiemetic consensus guidelines from several professional societies are widely available and updated regularly as new data emerges. Unfortunately, despite substantial research supporting the notion that guideline conformity improves CINV control, adherence to antiemetic guidelines is unsatisfactory. While studies are needed to identify specific barriers to guideline use and explore measures to enhance adherence, a novel approach has been taken to improve clinician adherence and patient compliance, with the development of a new combination antiemetic. NEPA is an oral fixed combination of a new highly selective NK1 receptor antagonist (RA), netupitant, and the pharmacologically and clinically distinct 5-HT3 RA, palonosetron. This convenient antiemetic combination offers guideline-consistent prophylaxis by targeting two critical pathways associated with CINV in a single oral dose administered only once per cycle. This paper will review and discuss the NEPA data in the context of how this first combination antiemetic may overcome some of the barriers interfering with adherence to antiemetic guidelines, enhance patient compliance, and offer a possible advance in the prevention of CINV for patients. PMID:26421300

  12. Evidence towards Improved Estimation of Respiratory Muscle Effort from Diaphragm Mechanomyographic Signals with Cardiac Vibration Interference Using Sample Entropy with Fixed Tolerance Values

    PubMed Central

    Sarlabous, Leonardo; Torres, Abel; Fiz, José A.; Jané, Raimon

    2014-01-01

    The analysis of amplitude parameters of the diaphragm mechanomyographic (MMGdi) signal is a non-invasive technique to assess respiratory muscle effort and to detect and quantify the severity of respiratory muscle weakness. The amplitude of the MMGdi signal is usually evaluated using the average rectified value or the root mean square of the signal. However, these estimations are greatly affected by the presence of cardiac vibration or mechanocardiographic (MCG) noise. In this study, we present a method for improving the estimation of the respiratory muscle effort from MMGdi signals that is robust to the presence of MCG. This method is based on the calculation of the sample entropy using fixed tolerance values (fSampEn), that is, with tolerance values that are not normalized by the local standard deviation of the window analyzed. The behavior of the fSampEn parameter was tested in synthesized mechanomyographic signals, with different ratios between the amplitude of the MCG and clean mechanomyographic components. As an example of application of this technique, the use of fSampEn was explored also in recorded MMGdi signals, with different inspiratory loads. The results with both synthetic and recorded signals indicate that the entropy parameter is less affected by the MCG noise, especially at low signal-to-noise ratios. Therefore, we believe that the proposed fSampEn parameter could improve estimates of respiratory muscle effort from MMGdi signals with the presence of MCG interference. PMID:24586436

  13. Evidence towards improved estimation of respiratory muscle effort from diaphragm mechanomyographic signals with cardiac vibration interference using sample entropy with fixed tolerance values.

    PubMed

    Sarlabous, Leonardo; Torres, Abel; Fiz, José A; Jané, Raimon

    2014-01-01

    The analysis of amplitude parameters of the diaphragm mechanomyographic (MMGdi) signal is a non-invasive technique to assess respiratory muscle effort and to detect and quantify the severity of respiratory muscle weakness. The amplitude of the MMGdi signal is usually evaluated using the average rectified value or the root mean square of the signal. However, these estimations are greatly affected by the presence of cardiac vibration or mechanocardiographic (MCG) noise. In this study, we present a method for improving the estimation of the respiratory muscle effort from MMGdi signals that is robust to the presence of MCG. This method is based on the calculation of the sample entropy using fixed tolerance values (fSampEn), that is, with tolerance values that are not normalized by the local standard deviation of the window analyzed. The behavior of the fSampEn parameter was tested in synthesized mechanomyographic signals, with different ratios between the amplitude of the MCG and clean mechanomyographic components. As an example of application of this technique, the use of fSampEn was explored also in recorded MMGdi signals, with different inspiratory loads. The results with both synthetic and recorded signals indicate that the entropy parameter is less affected by the MCG noise, especially at low signal-to-noise ratios. Therefore, we believe that the proposed fSampEn parameter could improve estimates of respiratory muscle effort from MMGdi signals with the presence of MCG interference. PMID:24586436

  14. Improvement of dumping syndrome and oversecretion of glucose-dependent insulinotropic polypeptide following a switch from olanzapine to quetiapine in a patient with schizophrenia.

    PubMed

    Watanabe, Aiko; Fukui, Naoki; Suzuki, Yutaro; Motegi, Takaharu; Igeta, Hirofumi; Tsuneyama, Nobuto; Someya, Toshiyuki

    2015-01-01

    Among the most important adverse effects of antipsychotics is abnormal glucose metabolism, which includes not only hyperglycemia but hyperinsulinemia and hypoglycemia. We have previously described five patients who experienced hypoglycemia during treatment with antipsychotics. Thus, an anamnesis of gastric surgery, which often causes dumping syndrome, and treatment with antipsychotics may synergistically induce hypoglycemia. We describe here a patient with schizophrenia under treatment of olanzapine and an anamnesis of gastric surgery, who experienced late dumping syndrome, hyperinsulinemia and overactivation of glucose-dependent insulinotropic polypeptide. Dumping syndrome, however, was improved after the patient was switched from olanzapine to quetiapine. PMID:25835510

  15. Biochemical switching device: how to turn on (off) the switch.

    PubMed

    Okamoto, M; Sakai, T; Hayashi, K

    1989-01-01

    We previously showed with computer simulations that cyclic enzyme systems have the reliability of ON-OFF types of operation (McCulloch-Pitts' neuronic equation) and the applicability for a switching circuit in a biocomputer. The switching time was inevitably determined in accordance with the difference in amount between two inputs of the system. This characteristic is, however, a disadvantage for practical use of a switching device; we need to improve the system in order for the switching time to optionally be changed. We shall present here how to turn on (off) the switch independently of the modes of two inputs. By introducing pulse perturbation, we could optionally set up the switching time of a cyclic enzyme system (biochemical switching device). PMID:2720139

  16. Optical switches and switching methods

    DOEpatents

    Doty, Michael

    2008-03-04

    A device and method for collecting subject responses, particularly during magnetic imaging experiments and testing using a method such as functional MRI. The device comprises a non-metallic input device which is coupled via fiber optic cables to a computer or other data collection device. One or more optical switches transmit the subject's responses. The input device keeps the subject's fingers comfortably aligned with the switches by partially immobilizing the forearm, wrist, and/or hand of the subject. Also a robust nonmetallic switch, particularly for use with the input device and methods for optical switching.

  17. Abacus switch: a new scalable multicast ATM switch

    NASA Astrophysics Data System (ADS)

    Chao, H. Jonathan; Park, Jin-Soo; Choe, Byeong-Seog

    1995-10-01

    This paper describes a new architecture for a scalable multicast ATM switch from a few tens to thousands of input ports. The switch, called Abacus switch, has a nonblocking memoryless switch fabric followed by small switch modules at the output ports; the switch has input and output buffers. Cell replication, cell routing, output contention resolution, and cell addressing are all performed distributedly in the Abacus switch so that it can be scaled up to thousnads input and output ports. A novel algorithm has been proposed to resolve output port contention while achieving input and output ports. A novel algorithm has been proposed to reolve output port contention while achieving input buffers sharing, fairness among the input ports, and multicast call splitting. The channel grouping concept is also adopted in the switch to reduce the hardware complexity and improve the switch's throughput. The Abacus switch has a regular structure and thus has the advantages of: 1) easy expansion, 2) relaxed synchronization for data and clock signals, and 3) building the switch fabric using existing CMOS technology.

  18. Experimental Study on Improving Unclamped Inductive Switching Characteristics of the New Power Metal Oxide Semiconductor Field Effect Transistor Employing Deep Body Contact

    NASA Astrophysics Data System (ADS)

    Ji, In‑Hwan; Choi, Young‑Hwan; Kim, Soo‑Seong; Choi, Yearn‑Ik; Han, Min‑Koo

    2006-04-01

    A new power metal oxide semiconductor field effect transistor (MOSFET) with deep body contact (DBC), which improves the avalanche energy capability, is proposed and verified by experimental results. For the experiment, a 60 V, 1 A power MOSFET employing DBC has been fabricated using a complementary metal oxide semiconductor (CMOS) compatible deep Si trench process. Previous simulations show that DBC alters the direction of the current flow from the edge to the bottom of the p-body under unclamped inductive switching (UIS) conditions. DBC also suppresses the activation of the parasitic bipolar transistor due to the reduction of the current density beneath the n+ source. Experimental results show that the ruggedness of the proposed power MOSFET is improved without sacrificing any other electrical characteristics and increasing device area.

  19. Improving high-resistance state uniformity and leakage current for polyimide-based resistive switching memory by rubbing post-treatment

    NASA Astrophysics Data System (ADS)

    Hsiao, Yu-Ping; Yang, Wen-Luh; Wu, Chi-Chang; Lin, Li-Min; Chin, Fun-Tat; Lin, Yu-Hsien; Yang, Ke-Luen

    2016-01-01

    In this study, a polyimide (PI) thin film is synthesized as a resistive switching layer for resistive random access memory (ReRAM) applications. The experimental results on polyimide thickness show that the Schottky effect between the interface of polyimide and metal thin films is the dominant mechanism in the high-resistance state (HRS). We, therefore, propose a rubbing post-treatment to improve the device performance. Results show that the uniformity and leakage of the memory in the HRS, as well as the power consumption in the low-resistance state (LRS), are improved. The power density of the set process is less than half after the rubbing post-treatment. Moreover, the power density of the reset process can be markedly decreased by about two orders of magnitude. In addition, the rubbed ReRAM exhibits a stable storage capability with seven orders of magnitude ION/IOFF current ratio at 85 °C.

  20. ION SWITCH

    DOEpatents

    Cook, B.

    1959-02-10

    An ion switch capable of transferring large magnitudes of power is described. An ion switch constructed in accordance with the invention includes a pair of spaced control electrodes disposed in a highly evacuated region for connection in a conventional circuit to control the passing of power therethrough. A controllable ionic conduction path is provided directiy between the control electrodes by a source unit to close the ion switch. Conventional power supply means are provided to trigger the source unit and control the magnitude, durations and pulse repetition rate of the aforementioned ionic conduction path.

  1. Theoretical study of thermally activated magnetization switching under microwave assistance: Switching paths and barrier height

    NASA Astrophysics Data System (ADS)

    Suto, H.; Kudo, K.; Nagasawa, T.; Kanao, T.; Mizushima, K.; Sato, R.; Okamoto, S.; Kikuchi, N.; Kitakami, O.

    2015-03-01

    Energy barrier height for magnetization switching is theoretically studied for a system with uniaxial anisotropy in a circularly polarized microwave magnetic field. A formulation of the Landau-Lifshitz-Gilbert equation in a rotating frame introduces an effective energy that includes the effects of both the microwave field and static field. This allows the effective-energy profiles to rigorously describe the switching paths and corresponding barrier height, which govern thermally activated magnetization switching under microwave assistance. We show that fixed points and limit cycles in the rotating frame lead to various switching paths and that under certain conditions, switching becomes a two-step process with an intermediate state.

  2. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets.

    PubMed

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  3. A Complex Inoculant of N2-Fixing, P- and K-Solubilizing Bacteria from a Purple Soil Improves the Growth of Kiwifruit (Actinidia chinensis) Plantlets

    PubMed Central

    Shen, Hong; He, Xinhua; Liu, Yiqing; Chen, Yi; Tang, Jianming; Guo, Tao

    2016-01-01

    Limited information is available if plant growth promoting bacteria (PGPB) can promote the growth of fruit crops through improvements in soil fertility. This study aimed to evaluate the capacity of PGPB, identified by phenotypic and 16S rRNA sequencing from a vegetable purple soil in Chongqing, China, to increase soil nitrogen (N), phosphorus (P), and potassium (K) availability and growth of kiwifruit (Actinidia chinensis). In doing so, three out of 17 bacterial isolates with a high capacity of N2-fixation (Bacillus amyloliquefaciens, XD-N-3), P-solubilization (B. pumilus, XD-P-1) or K-solubilization (B. circulans, XD-K-2) were mixed as a complex bacterial inoculant. A pot experiment then examined its effects of this complex inoculant on soil microflora, soil N2-fixation, P- and K-solubility and kiwifruit growth under four treatments. These treatments were (1) no-fertilizer and no-bacterial inoculant (Control), (2) no-bacterial inoculant and a full-rate of chemical NPK fertilizer (CF), (3) the complex inoculant (CI), and (4) a half-rate CF and full CI (1/2CF+CI). Results indicated that significantly greater growth of N2-fixing, P- and K-solubilizing bacteria among treatments ranked from greatest to least as under 1/2CF+CI ≈ CI > CF ≈ Control. Though generally without significant treatment differences in soil total N, P, or K, significantly greater soil available N, P, or K among treatments was, respectively, patterned as under 1/2CF+CI ≈ CI > CF ≈ Control, under 1/2CF+CI > CF > CI > Control or under 1/2CF+CI > CF ≈ CI > Control, indicating an improvement of soil fertility by this complex inoculant. In regards to plant growth, significantly greater total plant biomass and total N, P, and K accumulation among treatments were ranked as 1/2CF+CI ≈ CI > CF > Control. Additionally, significantly greater leaf polyphenol oxidase activity ranked as under CF > 1/2CF+CI ≈ Control ≈ CI, while leaf malondialdehyde contents as under Control > CI ≈ CF > 1/2CF

  4. Thermionic gas switch

    DOEpatents

    Hatch, G.L.; Brummond, W.A.; Barrus, D.M.

    1984-04-05

    The present invention is directed to an improved temperature responsive thermionic gas switch utilizing a hollow cathode and a folded emitter surface area. The folded emitter surface area of the thermionic switch substantially increases the on/off ratio by changing the conduction surface area involved in the two modes thereof. The improved switch of this invention provides an on/off ratio of 450:1 compared to the 10:1 ratio of the prior known thermionic switch, while providing for adjusting the on current. In the improved switch of this invention the conduction area is made small in the off mode, while in the on mode the conduction area is made large. This is achieved by utilizing a folded hollow cathode configuration and utilizing a folded emitter surface area, and by making the dimensions of the folds small enough so that a space charge will develop in the convolutions of the folds and suppress unignited current, thus limiting the current carrying surface in the off mode.

  5. Improving Molecular Detection of Fungal DNA in Formalin-Fixed Paraffin-Embedded Tissues: Comparison of Five Tissue DNA Extraction Methods Using Panfungal PCR▿

    PubMed Central

    Muñoz-Cadavid, C.; Rudd, S.; Zaki, S. R.; Patel, M.; Moser, S. A.; Brandt, M. E.; Gómez, B. L.

    2010-01-01

    DNA extraction from formalin-fixed paraffin-embedded (FFPE) tissues is difficult and requires special protocols in order to extract small amounts of DNA suitable for amplification. Most described methods report an amplification success rate between 60 and 80%; therefore, there is a need to improve molecular detection and identification of fungi in FFPE tissue. Eighty-one archived FFPE tissues with a positive Gomori methenamine silver (GMS) stain were evaluated using five different commercial DNA extraction kits with some modifications. Three different panfungal PCR assays were used to detect fungal DNA, and two housekeeping genes were used to assess the presence of amplifiable DNA and to detect PCR inhibitors. The sensitivities of the five extraction protocols were compared, and the quality of DNA detection (calculated for each kit as the number of housekeeping gene PCR-positive samples divided by the total number of samples) was 60 to 91% among the five protocols. The efficiencies of the three different panfungals used (calculated as the number of panfungal-PCR-positive samples divided by the number of housekeeping gene PCR-positive samples) were 58 to 93%. The panfungal PCR using internal transcribed spacer 3 (ITS3) and ITS4 primers yielded a product in most FFPE tissues. Two of the five DNA extraction kits (from TaKaRa and Qiagen) showed similar and promising results. However, one method (TaKaRa) could extract fungal DNA from 69 of the 74 FFPE tissues from which a housekeeping gene could be amplified and was also cost-effective, with a nonlaborious protocol. Factors such as sensitivity, cost, and labor will help guide the selection of the most appropriate method for the needs of each laboratory. PMID:20392915

  6. Parallelization and improvements of the generalized born model with a simple sWitching function for modern graphics processors.

    PubMed

    Arthur, Evan J; Brooks, Charles L

    2016-04-15

    Two fundamental challenges of simulating biologically relevant systems are the rapid calculation of the energy of solvation and the trajectory length of a given simulation. The Generalized Born model with a Simple sWitching function (GBSW) addresses these issues by using an efficient approximation of Poisson-Boltzmann (PB) theory to calculate each solute atom's free energy of solvation, the gradient of this potential, and the subsequent forces of solvation without the need for explicit solvent molecules. This study presents a parallel refactoring of the original GBSW algorithm and its implementation on newly available, low cost graphics chips with thousands of processing cores. Depending on the system size and nonbonded force cutoffs, the new GBSW algorithm offers speed increases of between one and two orders of magnitude over previous implementations while maintaining similar levels of accuracy. We find that much of the algorithm scales linearly with an increase of system size, which makes this water model cost effective for solvating large systems. Additionally, we utilize our GPU-accelerated GBSW model to fold the model system chignolin, and in doing so we demonstrate that these speed enhancements now make accessible folding studies of peptides and potentially small proteins. © 2016 Wiley Periodicals, Inc. PMID:26786647

  7. Terminator Operon Reporter: combining a transcription termination switch with reporter technology for improved gene synthesis and synthetic biology applications

    PubMed Central

    Zampini, Massimiliano; Mur, Luis A. J.; Rees Stevens, Pauline; Pachebat, Justin A.; Newbold, C. James; Hayes, Finbarr; Kingston-Smith, Alison

    2016-01-01

    Synthetic biology is characterized by the development of novel and powerful DNA fabrication methods and by the application of engineering principles to biology. The current study describes Terminator Operon Reporter (TOR), a new gene assembly technology based on the conditional activation of a reporter gene in response to sequence errors occurring at the assembly stage of the synthetic element. These errors are monitored by a transcription terminator that is placed between the synthetic gene and reporter gene. Switching of this terminator between active and inactive states dictates the transcription status of the downstream reporter gene to provide a rapid and facile readout of the accuracy of synthetic assembly. Designed specifically and uniquely for the synthesis of protein coding genes in bacteria, TOR allows the rapid and cost-effective fabrication of synthetic constructs by employing oligonucleotides at the most basic purification level (desalted) and without the need for costly and time-consuming post-synthesis correction methods. Thus, TOR streamlines gene assembly approaches, which are central to the future development of synthetic biology. PMID:27220405

  8. Terminator Operon Reporter: combining a transcription termination switch with reporter technology for improved gene synthesis and synthetic biology applications.

    PubMed

    Zampini, Massimiliano; Mur, Luis A J; Rees Stevens, Pauline; Pachebat, Justin A; Newbold, C James; Hayes, Finbarr; Kingston-Smith, Alison

    2016-01-01

    Synthetic biology is characterized by the development of novel and powerful DNA fabrication methods and by the application of engineering principles to biology. The current study describes Terminator Operon Reporter (TOR), a new gene assembly technology based on the conditional activation of a reporter gene in response to sequence errors occurring at the assembly stage of the synthetic element. These errors are monitored by a transcription terminator that is placed between the synthetic gene and reporter gene. Switching of this terminator between active and inactive states dictates the transcription status of the downstream reporter gene to provide a rapid and facile readout of the accuracy of synthetic assembly. Designed specifically and uniquely for the synthesis of protein coding genes in bacteria, TOR allows the rapid and cost-effective fabrication of synthetic constructs by employing oligonucleotides at the most basic purification level (desalted) and without the need for costly and time-consuming post-synthesis correction methods. Thus, TOR streamlines gene assembly approaches, which are central to the future development of synthetic biology. PMID:27220405

  9. Magnetic switch coupling to synchronize magnetic modulators

    DOEpatents

    Reed, K.W.; Kiekel, P.

    1999-04-27

    Apparatus for synchronizing the output pulses from a pair of magnetic switches is disclosed. An electrically conductive loop is provided between the pair of switches with the loop having windings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself. 13 figs.

  10. Magnetic switch coupling to synchronize magnetic modulators

    DOEpatents

    Reed, Kim W.; Kiekel, Paul

    1999-01-01

    Apparatus for synchronizing the output pulses from a pair of magnetic switches. An electrically conductive loop is provided between the pair of switches with the loop having windlings about the core of each of the magnetic switches. The magnetic coupling created by the loop removes voltage and timing variations between the outputs of the two magnetic switches caused by any of a variety of factors. The only remaining variation is a very small fixed timing offset caused by the geometry and length of the loop itself.

  11. Low inductance gas switching.

    SciTech Connect

    Chavez, Ray; Harjes, Henry Charles III; Wallace, Zachariah; Elizondo, Juan E.

    2007-10-01

    The laser trigger switch (LTS) is a key component in ZR-type pulsed power systems. In ZR, the pulse rise time through the LTS is > 200 ns and additional stages of pulse compression are required to achieve the desired <100 ns rise time. The inductance of the LTS ({approx}500nH) in large part determines the energy transfer time through the switch and there is much to be gained in improving system performance and reducing system costs by reducing this inductance. The current path through the cascade section of the ZR LTS is at a diameter of {approx} 6-inches which is certainly not optimal from an inductance point of view. The LTS connects components of much greater diameter (typically 4-5 feet). In this LDRD the viability of switch concepts in which the diameter of cascade section is greatly increased have been investigated. The key technical question to be answered was, will the desired multi-channel behavior be maintained in a cascade section of larger diameter. This LDRD proceeded in 2 distinct phases. The original plan for the LDRD was to develop a promising switch concept and then design, build, and test a moderate scale switch which would demonstrate the key features of the concept. In phase I, a switch concept which meet all electrical design criteria and had a calculated inductance of 150 nH was developed. A 1.5 MV test switch was designed and fabrication was initiated. The LDRD was then redirected due to budgetary concerns. The fabrication of the switch was halted and the focus of the LDRD was shifted to small scale experiments designed to answer the key technical question concerning multi-channel behavior. In phase II, the Multi-channel switch test bed (MCST) was designed and constructed. The purpose of MCST was to provide a versatile, fast turn around facility for the study the multi-channel electrical breakdown behavior of a ZR type cascade switch gap in a parameter space near that of a ZR LTS. Parameter scans on source impedance, gap tilt, gap spacing and

  12. Optical switch

    DOEpatents

    Reedy, Robert P.

    1987-01-01

    An optical switching device (10) is provided whereby light from a first glass fiber (16) or a second glass fiber (14) may be selectively transmitted into a third glass fiber (18). Each glass fiber is provided with a focusing and collimating lens system (26, 28, 30). In one mode of operation, light from the first glass fiber (16) is reflected by a planar mirror (36) into the third glass fiber (18). In another mode of operation, light from the second glass fiber (14) passes directly into the third glass fiber (18). The planar mirror (36) is attached to a rotatable table (32) which is rotated to provide the optical switching.

  13. [Fixed-dose combination].

    PubMed

    Nagai, Yoshio

    2015-03-01

    Many patients with type 2 diabetes mellitus(T2DM) do not achieve satisfactory glycemic control by monotherapy alone, and often require multiple oral hypoglycemic agents (OHAs). Combining OHAs with complementary mechanisms of action is fundamental to the management of T2DM. Fixed-dose combination therapy(FDC) offers a method of simplifying complex regimens. Efficacy and tolerability appear to be similar between FDC and treatment with individual agents. In addition, FDC can enhance adherence and improved adherence may result in improved glycemic control. Four FDC agents are available in Japan: pioglitazone-glimepiride, pioglitazone-metformin, pioglitazone-alogliptin, and voglibose-mitiglinide. In this review, the advantages and disadvantages of these four combinations are identified and discussed. PMID:25812374

  14. Switching Transistor

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Westinghouse Electric Corporation's D60T transistors are used primarily as switching devices for controlling high power in electrical circuits. It enables reduction in the number and size of circuit components and promotes more efficient use of energy. Wide range of application from a popcorn popper to a radio frequency generator for solar cell production.

  15. Development of high temperature diffusion technology for edge termination and switching behavior improvement of silicon carbide p-i-n diodes

    NASA Astrophysics Data System (ADS)

    Bolotnikov, Alexander V.

    forward voltage drop (3.3 V at 100 A/cm2) and high blocking voltage (more than 2500 V). A fabrication technology of p-i-n diodes with reduced switching losses through the incorporation of deep recombination centers via diffusion of boron was developed. The improvement of reverse recovery characteristic is attributed to the effect of localized lifetime control by recombination centers created by diffused boron. It is demonstrated that p-i-n diodes produced by high temperature diffusion exhibit better switching capability compared to epi-grown p-i-n diodes. The improved behavior is attributed to the reduced lifetime region created by the diffused boron layer. The good performance of SiC devices fabricated with diffusion implementation confirmed the viability of this process.

  16. Communication: Toward an improved control of the fixed-node error in quantum Monte Carlo: The case of the water molecule

    NASA Astrophysics Data System (ADS)

    Caffarel, Michel; Applencourt, Thomas; Giner, Emmanuel; Scemama, Anthony

    2016-04-01

    All-electron Fixed-node Diffusion Monte Carlo calculations for the nonrelativistic ground-state energy of the water molecule at equilibrium geometry are presented. The determinantal part of the trial wavefunction is obtained from a selected Configuration Interaction calculation [Configuration Interaction using a Perturbative Selection done Iteratively (CIPSI) method] including up to about 1.4 × 106 of determinants. Calculations are made using the cc-pCVnZ family of basis sets, with n = 2 to 5. In contrast with most quantum Monte Carlo works no re-optimization of the determinantal part in presence of a Jastrow is performed. For the largest cc-pCV5Z basis set the lowest upper bound for the ground-state energy reported so far of -76.437 44(18) is obtained. The fixed-node energy is found to decrease regularly as a function of the cardinal number n and the Complete Basis Set limit associated with exact nodes is easily extracted. The resulting energy of -76.438 94(12) — in perfect agreement with the best experimentally derived value — is the most accurate theoretical estimate reported so far. We emphasize that employing selected configuration interaction nodes of increasing quality in a given family of basis sets may represent a simple, deterministic, reproducible, and systematic way of controlling the fixed-node error in diffusion Monte Carlo.

  17. Aflibercept in persistent neovascular AMD: comparison of different treatment strategies in switching therapy.

    PubMed

    Ricci, F; Parravano, M; Regine, F; Sciamanna, M; Tedeschi, M; Missiroli, F; Varano, M

    2016-08-01

    PurposeTo evaluate the effects of aflibercept administered according to a pro re nata (PRN) or Fixed Regimen to patients with neovascular AMD and persistent intraretinal/subretinal fluid (IRF/SRF) despite three consecutive ranibizumab injections.MethodsPatients were switched to aflibercept injection (IVA) administered according to a PRN or to a fixed regimen for 1 year in two different retina centers. At baseline each patient underwent a complete ophthalmologic evaluation, including best-corrected visual acuity assessment (BCVA ETDRS chart), fluorescein, and indocyanine green angiography and OCT.ResultsEach group included 36 eyes. After 1 year the PRN group showed BCVA stabilization (63 vs 60 letters, P=0.33), whereas fixed regimen group showed significant BCVA improvement (68 vs 71, P=0.008). The median central retinal thickness decreased by 94 μm in the PRN (P=0.002) and by 148 μm in the fixed regimen group (P≤0.001). Complete IRF/SRF reabsorption was found in 58% of eyes in the PRN and in 42% of eyes in the fixed regimen group. At 1-year visit, the percentage of eyes with pigment epithelium detachment did not significantly decrease, but a height reduction was recorded in both groups. The median number of IVA was 3.5 in the PRN and 7 in the fixed regimen group.ConclusionThe switch to aflibercept with both treatment strategies enabled improvement in morphological parameters and stabilization of visual acuity. BCVA improvement and reduction in vision loss with reduction in retinal thickness, fluid and PED height was achieved with the fixed regimen in previously treated nAMD after 1 year. PMID:27229701

  18. Switching strategies to optimize search

    NASA Astrophysics Data System (ADS)

    Shlesinger, Michael F.

    2016-03-01

    Search strategies are explored when the search time is fixed, success is probabilistic and the estimate for success can diminish with time if there is not a successful result. Under the time constraint the problem is to find the optimal time to switch a search strategy or search location. Several variables are taken into account, including cost, gain, rate of success if a target is present and the probability that a target is present.

  19. Power Quality Improvement in Bridgeless Ac-Dc Converter Based Multi-output Switched Mode Power Supply

    NASA Astrophysics Data System (ADS)

    Singh, Shihka; Singh, Bhim; Bhuvaneswari, G.; Bist, Vashist

    2014-12-01

    Computer power supplies are required to have multiple isolated regulated dc voltages with low ripple content and high input power factor at the utility interface. A dc-dc converter is used for obtaining these isolated multi-output dc voltages with excellent regulation. In this paper, a non-isolated ac-dc converter is proposed as the first stage converter to obtain a regulated dc output rather than using a simple uncontrolled diode bridge rectifier at the front end. A dc-dc converter is used at the second stage that has a high frequency transformer with multiple secondary windings to obtain different dc voltage levels at the output. The proposed bridgeless converter based power supply is designed using fundamental design equations, and different component values are calculated. Extensive simulations are carried out to demonstrate the improved performance of the proposed bridgeless converter based multi-output computer power supply at varying source voltages and load conditions. Experimental validation of the power supply is carried on a developed hardware prototype, and the test results are compared with the simulated performance for design verification.

  20. Large arrays and properties of 3-terminal graphene nanoelectromechanical switches.

    PubMed

    Liu, Xinghui; Suk, Ji Won; Boddeti, Narasimha G; Cantley, Lauren; Wang, Luda; Gray, Jason M; Hall, Harris J; Bright, Victor M; Rogers, Charles T; Dunn, Martin L; Ruoff, Rodney S; Bunch, J Scott

    2014-03-12

    Large arrays of 3-terminal nanoelectromechanical graphene switches are fabricated. The switch is designed with a novel geometry that leads to low actuation voltages and improved mechanical integrity, while reducing adhesion forces, which improves the reliability of the switch. A finite element model including non-linear electromechanics is used to simulate the switching behavior and to deduce a scaling relation between the switching voltage and device dimensions. PMID:24339026

  1. Impact of electrically formed interfacial layer and improved memory characteristics of IrOx/high-κx/W structures containing AlOx, GdOx, HfOx, and TaOx switching materials

    PubMed Central

    2013-01-01

    Improved switching characteristics were obtained from high-κ oxides AlOx, GdOx, HfOx, and TaOx in IrOx/high-κx/W structures because of a layer that formed at the IrOx/high-κx interface under external positive bias. The surface roughness and morphology of the bottom electrode in these devices were observed by atomic force microscopy. Device size was investigated using high-resolution transmission electron microscopy. More than 100 repeatable consecutive switching cycles were observed for positive-formatted memory devices compared with that of the negative-formatted devices (only five unstable cycles) because it contained an electrically formed interfacial layer that controlled ‘SET/RESET’ current overshoot. This phenomenon was independent of the switching material in the device. The electrically formed oxygen-rich interfacial layer at the IrOx/high-κx interface improved switching in both via-hole and cross-point structures. The switching mechanism was attributed to filamentary conduction and oxygen ion migration. Using the positive-formatted design approach, cross-point memory in an IrOx/AlOx/W structure was fabricated. This cross-point memory exhibited forming-free, uniform switching for >1,000 consecutive dc cycles with a small voltage/current operation of ±2 V/200 μA and high yield of >95% switchable with a large resistance ratio of >100. These properties make this cross-point memory particularly promising for high-density applications. Furthermore, this memory device also showed multilevel capability with a switching current as low as 10 μA and a RESET current of 137 μA, good pulse read endurance of each level (>105 cycles), and data retention of >104 s at a low current compliance of 50 μA at 85°C. Our improvement of the switching characteristics of this resistive memory device will aid in the design of memory stacks for practical applications. PMID:24011235

  2. Impact of electrically formed interfacial layer and improved memory characteristics of IrOx/high-κx/W structures containing AlOx, GdOx, HfOx, and TaOx switching materials

    NASA Astrophysics Data System (ADS)

    Prakash, Amit; Maikap, Siddheswar; Banerjee, Writam; Jana, Debanjan; Lai, Chao-Sung

    2013-09-01

    Improved switching characteristics were obtained from high-κ oxides AlOx, GdOx, HfOx, and TaOx in IrOx/high-κx/W structures because of a layer that formed at the IrOx/high-κx interface under external positive bias. The surface roughness and morphology of the bottom electrode in these devices were observed by atomic force microscopy. Device size was investigated using high-resolution transmission electron microscopy. More than 100 repeatable consecutive switching cycles were observed for positive-formatted memory devices compared with that of the negative-formatted devices (only five unstable cycles) because it contained an electrically formed interfacial layer that controlled `SET/RESET' current overshoot. This phenomenon was independent of the switching material in the device. The electrically formed oxygen-rich interfacial layer at the IrOx/high-κx interface improved switching in both via-hole and cross-point structures. The switching mechanism was attributed to filamentary conduction and oxygen ion migration. Using the positive-formatted design approach, cross-point memory in an IrOx/AlOx/W structure was fabricated. This cross-point memory exhibited forming-free, uniform switching for >1,000 consecutive dc cycles with a small voltage/current operation of ±2 V/200 μA and high yield of >95% switchable with a large resistance ratio of >100. These properties make this cross-point memory particularly promising for high-density applications. Furthermore, this memory device also showed multilevel capability with a switching current as low as 10 μA and a RESET current of 137 μA, good pulse read endurance of each level (>105 cycles), and data retention of >104 s at a low current compliance of 50 μA at 85°C. Our improvement of the switching characteristics of this resistive memory device will aid in the design of memory stacks for practical applications.

  3. Feasibility of a two-step culture method to improve the CO2-fixing efficiency of nonphotosynthetic microbial community and simultaneously decrease the spontaneous oxidative precipitates from mixed electron donors.

    PubMed

    Hu, Jiajun; Wang, Lei; Zhang, Shiping; Le, Yiquan; Fu, Xiaohua

    2014-08-01

    When compared with H2, mixed electron donors (MED), comprising S(2-), S2O3 (2-), and NO2 (-), could generally improve the CO2-fixing efficiency of nonphotosynthetic microbial communities (NPMCs). However, a large amount of abiotic precipitates combined with bacteria produced during culture may be unfavorable for the recycling and reuse of bacteria. The main component of the abiotic precipitates is S(0), which influences the enrichment and reuse of bacteria but is not conducive for CO2 fixation in the subsequent step. In this study, a two-step culture method (TSCM), employing H2 and MED, respectively, was verified to be feasible for improving the CO2-fixing efficiency of NPMCs in the second step. In the TSCM, the net-fixed CO2 increased to 854 mg/L and abiotic precipitates were not produced in the medium. Sequence analysis of 16 s rDNA from NPMC indicated the presence of microbial symbioses in the NPMC, supporting the possible applications of TSCM. PMID:24980751

  4. The financial and service implications of splitting fixed-dose antiretroviral drugs - a case study.

    PubMed

    Taylor, R; Carlin, E; Sadique, Z; Ahmed, I; Adams, E J

    2015-02-01

    In 2010/2011, regional commissioners withdrew payment for the fixed-dose combination Combivir, forcing a switch to component drugs. This was deemed clinically acceptable and annual savings of £44 k expected. We estimated the true costs of switching and examined patient outcomes. Information for 46 patients using Combivir was extracted from case notes for each clinical contact in the 12 months pre- and post-switch (clinician seen, tests, antiretrovirals). Post-switch care costs £93/patient more annually versus pre-switch (95% CI £424 to £609), yielding £4278/year more post-switch for all patients. Drug and pathology costs were more expensive post-switch and extra clinical visits required. None of these results were statistically significant. Forty-two per cent of patients switched directly or in the subsequent year to an alternative fixed-dose combination rather than generics. Costs in this group were significantly higher post-switch driven by drug cost. Six patients (13%) reported problems with the switch including confusion around dosing and new side effects. As less-expensive generic antiretroviral drugs become available, it may appear cheaper to switch from fixed-dose combinations to component drugs. However, the additional clinical costs involved may outweigh the initial cost savings of the drugs and switching may cause confusion for some patients, risking loss of adherence. PMID:24700200

  5. Nanoelectromechanical contact switches

    NASA Astrophysics Data System (ADS)

    Loh, Owen Y.; Espinosa, Horacio D.

    2012-05-01

    Nanoelectromechanical (NEM) switches are similar to conventional semiconductor switches in that they can be used as relays, transistors, logic devices and sensors. However, the operating principles of NEM switches and semiconductor switches are fundamentally different. These differences give NEM switches an advantage over semiconductor switches in some applications -- for example, NEM switches perform much better in extreme environments -- but semiconductor switches benefit from a much superior manufacturing infrastructure. Here we review the potential of NEM-switch technologies to complement or selectively replace conventional complementary metal-oxide semiconductor technology, and identify the challenges involved in the large-scale manufacture of a representative set of NEM-based devices.

  6. "Platform switching": serendipity.

    PubMed

    Kalavathy, N; Sridevi, J; Gehlot, Roshni; Kumar, Santosh

    2014-01-01

    Implant dentistry is the latest developing field in terms of clinical techniques, research, material science and oral rehabilitation. Extensive work is being done to improve the designing of implants in order to achieve better esthetics and function. The main drawback with respect to implant restoration is achieving good osseointegration along with satisfactory stress distribution, which in turn will improve the prognosis of implant prosthesis by reducing the crestal bone loss. Many concepts have been developed with reference to surface coating of implants, surgical techniques for implant placement, immediate and delayed loading, platform switching concept, etc. This article has made an attempt to review the concept of platform switching was in fact revealed accidentally due to the nonavailability of the abutment appropriate to the size of the implant placed. A few aspect of platform switching, an upcoming idea to reduce crestal bone loss have been covered. The various methods used for locating and preparing the data were done through textbooks, Google search and related articles. PMID:24992863

  7. THYRATRON SWITCH

    DOEpatents

    Creveling, R.; Bourgeois, N.A. Jr.

    1959-04-21

    An arrangement for utilizing a thyratron as a noise free switch is described. It has been discovered that the voltage between plate and cathode of a thyratron will oscillate, producing voltage spikes, if the tube carries only a fraction of its maximum rated current. These voltage spikes can produce detrimental effects where the thyratron is used in critical timing circuits. To alleviate this problem the disclosed circuit provides a charged capacitor and a resistor in parallel with the tube and of such value that the maximum current will flow from the capacitor through the thyratron when it is triggered. During this time the signal current is conducted through the tube, before the thyratron voltage starts to oscillate, and the signal current output is free of noise spikes.

  8. Switching to second-generation tyrosine kinase inhibitor improves the response and outcome of frontline imatinib-treated patients with chronic myeloid leukemia with more than 10% of BCR-ABL/ABL ratio at 3 months.

    PubMed

    Casado, Luis-Felipe; García-Gutiérrez, José-Valentín; Massagué, Isabel; Giraldo, Pilar; Pérez-Encinas, Manuel; de Paz, Raquel; Martínez-López, Joaquín; Bautista, Guiomar; Osorio, Santiago; Requena, María-José; Palomera, Luis; Peñarrubia, María-Jesús; Calle, Carmen; Hernández-Rivas, José-Ángel; Burgaleta, Carmen; Maestro, Begoña; García-Ormeña, Nuria; Steegmann, Juan-Luis

    2015-07-01

    Chronic myeloid leukemia patients display heterogeneous responses to imatinib. Survival depends on baseline clinical characteristics (including prognostic scoring systems) and on early response (such as >10% BCR-ABL/ABL ratio at 3 months of therapy). The results of switching to second-generation tyrosine kinase inhibitors (2GTKIs) may contain a bias since, in the majority of these studies, patients who switch treatment due to intolerance or failure are censored or excluded. We analyzed the Spanish Registry data on switching in an intention-to-treat analysis of patients in standard clinical practice. Switching to 2GTKIs improves responses from 45% to 75% of complete cytogenetic response (CCyR) and from 15% to 45% of major molecular response (MMR) in the group without molecular response 1 (MR1) at 3 months and from 70% to 87% in CCyR and from 52% to 87% in MMR in the group with MR1. The final response rate is poorer in the group with no MR1 at 3 months. Nevertheless, the differences in the rates of response were not translated into differences in major events (transformations or deaths), and the final progression-free survival and overall survival were similar. PMID:25756742

  9. Switching to second-generation tyrosine kinase inhibitor improves the response and outcome of frontline imatinib-treated patients with chronic myeloid leukemia with more than 10% of BCR-ABL/ABL ratio at 3 months

    PubMed Central

    Casado, Luis-Felipe; García-Gutiérrez, José-Valentín; Massagué, Isabel; Giraldo, Pilar; Pérez-Encinas, Manuel; de Paz, Raquel; Martínez-López, Joaquín; Bautista, Guiomar; Osorio, Santiago; Requena, María-José; Palomera, Luis; Peñarrubia, María-Jesús; Calle, Carmen; Hernández-Rivas, José-Ángel; Burgaleta, Carmen; Maestro, Begoña; García-Ormeña, Nuria; Steegmann, Juan-Luis

    2015-01-01

    Chronic myeloid leukemia patients display heterogeneous responses to imatinib. Survival depends on baseline clinical characteristics (including prognostic scoring systems) and on early response (such as >10% BCR-ABL/ABL ratio at 3 months of therapy). The results of switching to second-generation tyrosine kinase inhibitors (2GTKIs) may contain a bias since, in the majority of these studies, patients who switch treatment due to intolerance or failure are censored or excluded. We analyzed the Spanish Registry data on switching in an intention-to-treat analysis of patients in standard clinical practice. Switching to 2GTKIs improves responses from 45% to 75% of complete cytogenetic response (CCyR) and from 15% to 45% of major molecular response (MMR) in the group without molecular response 1 (MR1) at 3 months and from 70% to 87% in CCyR and from 52% to 87% in MMR in the group with MR1. The final response rate is poorer in the group with no MR1 at 3 months. Nevertheless, the differences in the rates of response were not translated into differences in major events (transformations or deaths), and the final progression-free survival and overall survival were similar. PMID:25756742

  10. Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, part II: multilayer biofilm diffusional model.

    PubMed

    Sen, Dipankar; Randall, Clifford W

    2008-07-01

    Research was undertaken to develop a diffusional model of the biofilm that can be applied in lieu of a semi-empirical model to upgrade an activated sludge system to an integrated fixed-film activated sludge (IFAS) or moving-bed biofilm reactor (MBBR) system. The model has been developed to operate with up to 12 cells (reactors) in series, with biofilm media incorporated to one or more of the zone cells, except the anaerobic zone cells. The values of the kinetic parameters for the model were measured using pilot-scale activated sludge, IFAS, and MBBR systems. The biofilm is divided into 12 layers and has a stagnant liquid layer. Diffusion and substrate utilization are calculated for each layer. The equations are solved simultaneously using a finite difference technique. The biofilm flux model is then linked to the activated sludge model. Advanced features include the ability to compute the biofilm thickness and the effect of biofilm thickness on performance. The biofilm diffusional model is also used to provide information and create a table of biofilm yields at different substrate concentrations that can be used in the semi-empirical model. PMID:18710146

  11. Use of softening agents to improve the production of formalin-fixed, paraffin-embedded sections of nail tissue: an assessment.

    PubMed

    Orchard, G E; Torres, J; Sounthararajah, R

    2008-01-01

    The use of tissue softeners to enhance the quality of tissue sections of heavily keratotic tissue is not widely published. There are very few indicators in the scientific literature that attempt to compare and contrast the benefits and disadvantages of such techniques, as most are passed down through word of mouth rather than through published data. This study attempts to present a preliminary evaluation of several methods employing tissue softeners to facilitate the preparation of reproducible, good-quality formalin-fixed, paraffin-embedded sections of nail tissue. A standard 10-minute surface application of each softener is employed for all paraffin-embedded tissue in order to ensure consistency. The results show that the use of Veet (hair remover), Fairy Liquid or fabric conditioner provides the most beneficial results. Thus, widely available products can be used in preference to specific commercially produced reagents that have no clear benefits and can cost considerably more to purchase. This study will form the basis of a more in-depth evaluation of the most beneficial softeners, in an attempt to determine optimal parameters for their use in routine histopathology laboratories. PMID:19055107

  12. [Improvement in glycemic control, cardiovascular risk factors and anthropometric data in type 2 diabetic patients after the switch from biphasic human insulin to biphasic premix analog insulin aspart].

    PubMed

    Gero, László; Gyimesi, András; Hidvégi, Tibor; Jánosi, István

    2009-08-30

    Long-term studies involving large number of type 2 diabetic patients supplied evidence that constant adequate metabolic control may prevent the late (micro- and macrovascular) diabetic complications. In the present non-interventional, retrospective study, authors performed an analysis of type 2 diabetic patients who had been previously treated with biphasic human insulin (BHI) and their therapy was changed to biphasic analog insulin aspart 30/70 (BIAsp = NovoMix 30). The switch of the insulin therapy was carried out in years 2007 and 2008 with the cooperation of 50 accredited diabetes centers. Data were obtained at the time of therapeutical change and six months later. The number of suitable patients was 2898 with an age of 66.20 +/- 10.10 year, and the duration of diabetes was >10 years in 43% of the patients. After the six-month therapy with NovoMix 30, the mean HbA 1c level decreased statistically significantly from the initial value of 9.10 +/- 1.44% to 7.62 +/- 1.00% ( p < 0.001). The lipid profile also improved although target values were not always attained. A reduction was also observed in both systolic and diastolic blood pressure. Mean body weight decreased from 84.2 +/- 14.9 kg to 82.6 +/- 13.9 kg ( p < 0.01). All these changes occurred in spite of a significantly reduced daily insulin dose (48.4 +/- 17.6 IU) as compared with the initial value (49.0 +/- 17.4 IU, p < 0.001). A marked decrement was also observed in the frequency of hypoglycemic reactions. These results confirm that treatment with NovoMix 30 insulin leads to a significant amelioration of glycemic control as reflected by the decreased level of HbA 1c and the higher proportion of patients attaining the target value, as well as the lower frequency of hypoglycemic episodes. The significant improvements in cardiovascular risk factors are also important, but the explanation is still missing and would require the accomplishment of prospective, controlled studies. PMID:19692308

  13. Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, part III: analysis and verification.

    PubMed

    Sen, Dipankar; Randall, Clifford W

    2008-07-01

    Research was undertaken to analyze and verify a model that can be applied to activated sludge, integrated fixed-film activated sludge (IFAS), and moving-bed biofilm reactor (MBBR) systems. The model embeds a biofilm model into a multicell activated sludge model. The advantage of such a model is that it eliminates the need to run separate computations for a plant being retrofitted from activated sludge to IFAS or MBBR. The biofilm flux rates for organics, nutrients, and biomass can be computed by two methods-a semi-empirical model of the biofilm that is relatively simpler, or a diffusional model of the biofilm that is computationally intensive. Biofilm support media can be incorporated to the anoxic and aerobic cells, but not the anaerobic cells. The model can be run for steady-state and dynamic simulations. The model was able to predict the changes in nitrification and denitrification at both pilot- and full-scale facilities. The semi-empirical and diffusional models of the biofilm were both used to evaluate the biofilm flux rates for media at different locations. The biofilm diffusional model was used to compute the biofilm thickness and growth, substrate concentrations, volatile suspended solids (VSS) concentration, and fraction of nitrifiers in each layer inside the biofilm. Following calibration, both models provided similar effluent results for reactor mixed liquor VSS and mixed liquor suspended solids and for the effluent organics, nitrogen forms, and phosphorus concentrations. While the semi-empirical model was quicker to run, the diffusional model provided additional information on biofilm thickness, quantity of growth in the biofilm, and substrate profiles inside the biofilm. PMID:18710147

  14. Improved computational model (AQUIFAS) for activated sludge, integrated fixed-film activated sludge, and moving-bed biofilm reactor systems, Part I: Semi-empirical model development.

    PubMed

    Sen, Dipankar; Randall, Clifford W

    2008-05-01

    Research was undertaken to develop a model for activated sludge, integrated fixed-film activated sludge (IFAS), and moving-bed biofilm reactor (MBBR) systems. The model can operate with up to 12 cells (reactors) in series, with biofilm media incorporated to one or more cells, except the anaerobic cells. The process configuration can be any combination of anaerobic, anoxic, aerobic, post-anoxic with or without supplemental carbon, and reaeration; it can also include any combination of step feed and recycles, including recycles for mixed liquor, return activated sludge, nitrates, and membrane bioreactors. This paper presents the structure of the model. The model embeds a biofilm model into a multicell activated sludge model. The biofilm flux rates for organics, nutrients, and biomass can be computed by two methods--a semi-empirical model of the biofilm that is relatively simpler, or a diffusional model that is computationally intensive. The values of the kinetic parameters for the model were measured using pilot-scale activated sludge, IFAS, and MBBR systems. For the semiempirical version, a series of Monod equations were developed for chemical oxygen demand, ammonium-nitrogen, and oxidized-nitrogen fluxes to the biofilm. Within the equations, a second Monod expression is used to simulate the effect of changes in biofilm thickness and fraction nitrifiers in the biofilm. The biofilm flux model is then linked to the activated sludge model. The diffusional model and the verification of the models are presented in subsequent papers (Sen and Randall, 2008a, 2008b). The model can be used to quantify the amount of media and surface area required to achieve nitrification, identify the best locations for the media, and optimize the dissolved oxygen levels and nitrate recycle rates. Some of the advanced features include the ability to apply different media types and fill fractions in cells; quantify nitrification, denitrification, and biomass production in the biofilm and

  15. Disruption of the Glycine Cleavage System Enables Sinorhizobium Fredii USDA257 to Form Nitrogen-fixing Nodules on Agonomically Improved North American Soybean Cultivars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The symbiosis between Sinorhizobium fredii USDA257 and soybean [Glycine max (L.) Merr.] exhibits a high degree of cultivar specificity. USDA257 nodulates primitive soybean cultivars but fails to nodulate agronomically improved cultivars such as McCall. In this study we provide evidence for the invol...

  16. Extended lifetime railgap switch

    SciTech Connect

    Cohn, D.B.; Mendoza, P.J.

    1988-02-02

    In a railgap switch of the type having an elongate blade electrode made of conductive material, an elongate housing made of insulating material for supporting the blade electrode and plate electrode in opposed relation extending in the same direction with the blade centered over the plate and separated therefrom by a gap, and a gas filling the housing and the gap, the gas being selected to breakdown and switch from a highly insulative state to a highly conductive state upon application of a high voltage across the blade and plate electrodes, the improvement is described comprising: forming the blade with laterally extending transverse wing portions at the edge of the blade and adjacent the gap so as to extend in spaced parallel relation to the surface of the plate, the blade generally following the contour thereof to form an inverted T-shape structure with the wing portions extending transversely of the elongate dimension of the blade. The wing portions terminating in a pair of spaced parallel edges extending along the elongate direction of the blade to thereby create two spaced elongate edges along which arcs form serving to divide the erosion effects of discharge between them, the current through each edge being one-half of that in single-edge devices with ablation wear reduced accordingly to give significantly larger switch lifetime. The blade and wing portions limiting ablation erosion of the edges in a direction generally align with the plate contour so that the edge-to-plate separation remains substantially constant.

  17. Switch Transcripts in Immunoglobulin Class Switching

    NASA Astrophysics Data System (ADS)

    Lorenz, Matthias; Jung, Steffen; Radbruch, Andreas

    1995-03-01

    B cells can exchange gene segments for the constant region of the immunoglobulin heavy chain, altering the class and effector function of the antibodies that they produce. Class switching is directed to distinct classes by cytokines, which induce transcription of the targeted DNA sequences. These transcripts are processed, resulting in spliced "switch" transcripts. Switch recombination can be directed to immunoglobulin G1 (IgG1) by the heterologous human metallothionein II_A promoter in mutant mice. Induction of the structurally conserved, spliced switch transcripts is sufficient to target switch recombination to IgG1, whereas transcription alone is not.

  18. [Advantages of fixed combinations].

    PubMed

    Lachkar, Y

    2008-07-01

    Fixed combinations are indicated in the treatment of glaucoma and ocular hypertension when monotherapy does not sufficiently reduce IOP. Fixed combinations show better efficacy than the instillation of each separate component and are at least equivalent to the administration of both components in a separate association. They simplify treatment, increase compliance and quality of life, and decrease exposure to preservatives. Although they are less aggressive for patients when a new drug needs to be added, the use of fixed combinations should not decrease the follow-up. PMID:18957922

  19. Latching relay switch assembly

    DOEpatents

    Duimstra, Frederick A.

    1991-01-01

    A latching relay switch assembly which includes a coil section and a switch or contact section. The coil section includes at least one permanent magnet and at least one electromagnet. The respective sections are, generally, arranged in separate locations or cavities in the assembly. The switch is latched by a permanent magnet assembly and selectively switched by an overriding electromagnetic assembly.

  20. Switching portfolios.

    PubMed

    Singer, Y

    1997-08-01

    A constant rebalanced portfolio is an asset allocation algorithm which keeps the same distribution of wealth among a set of assets along a period of time. Recently, there has been work on on-line portfolio selection algorithms which are competitive with the best constant rebalanced portfolio determined in hindsight (Cover, 1991; Helmbold et al., 1996; Cover and Ordentlich, 1996). By their nature, these algorithms employ the assumption that high returns can be achieved using a fixed asset allocation strategy. However, stock markets are far from being stationary and in many cases the wealth achieved by a constant rebalanced portfolio is much smaller than the wealth achieved by an ad hoc investment strategy that adapts to changes in the market. In this paper we present an efficient portfolio selection algorithm that is able to track a changing market. We also describe a simple extension of the algorithm for the case of a general transaction cost, including the transactions cost models recently investigated in (Blum and Kalai, 1997). We provide a simple analysis of the competitiveness of the algorithm and check its performance on real stock data from the New York Stock Exchange accumulated during a 22-year period. On this data, our algorithm outperforms all the algorithms referenced above, with and without transaction costs. PMID:9730020

  1. Bulk-titanium for MEMS switches

    NASA Astrophysics Data System (ADS)

    Ding, Changsong

    RF-MEMS switches offer great potential benefits such as high isolation, low insertion loss, low power consumption, and excellent linearity characteristics. Most MEMS switches are fabricated using surface micromachining techniques by taking advantage of the IC processing techniques. Little work has been done on bulk micromachining for fabricating MEMS switches. This work contributes to two main areas in the MEMS switch field, (1) a Sacrificial-Layer-Free (SLF) method to fabricate switches using bulk titanium MEMS (BT-MEMS) and multilayer lamination techniques, and (2) development of a novel composite contact material and integration into BT-MEMS switches for testing. This approach for fabricating MEMS switches offers advantages from five aspects to attack the fabrication and reliability issues. Four generations of Bulk-Ti MEMS (BT-MEMS) switches were developed. They were improved through developments of high aspect ratio bulk Ti etching, Titanium-On-Insulator structure, multilayer lamination, mechanical design, and a new contact material. The first generation proved the feasibility of the concept of the BT-MEMS switch. The second generation had a good contact resistance. Development of the novel Nano-Structured-Titania (NST) composite material allowed further improvement of the third generation. We used the BT-MEMS switch as a platform for testing this new, novel contact material. Due to the preferred surface properties of the NST-metal composite material such as roughness and hardness, the third generation switched above 15 billion contact cycles without adhesion failure. Contact resistance was further improved in the fourth generation switch by integrating the NST-metal composite material into the top part as bumps. Above 100 million cycles with good contact resistance values were achieved.

  2. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E.

    1990-03-06

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  3. Radiation hard vacuum switch

    DOEpatents

    Boettcher, Gordon E.

    1990-01-01

    A vacuum switch with an isolated trigger probe which is not directly connected to the switching electrodes. The vacuum switch within the plasmatron is triggered by plasma expansion initiated by the trigger probe which travels through an opening to reach the vacuum switch elements. The plasma arc created is directed by the opening to the space between the anode and cathode of the vacuum switch to cause conduction.

  4. Experimental investigation of resonant MEMS switch with ac actuation

    NASA Astrophysics Data System (ADS)

    Pal, Jitendra; Zhu, Yong; Wang, Boyi; Lu, Junwei; Khan, Fahimullah; Viet Dao, Dzung; Wang, Yifan

    2016-06-01

    In this letter, modeling, analysis, and experimental investigation for a resonant MEMS switch are presented. The resonant switch harnesses its mechanical resonance to lower the required actuation voltage by a substantial factor over the switch with static actuation. With alternating actuation voltage at its mechanical resonance frequency of 6.6 kHz, the average capacitance is tuned by changing the gap between fixed and movable electrodes. Based on the proposed actuation method, the device offers 57.44% lower actuation voltage compared with the switch with static actuation.

  5. Mercury switch with non-wettable electrodes

    SciTech Connect

    Karnowsky, M.M.; Yost, F.G.

    1987-03-24

    This patent describes a mercury switch having spaced conductive electrodes with contacts thereon which are bridged by a mercury pool when the switch is closed and free of the mercury pool when the switch is open. The improvement described here comprises: contacts on the conductive electrodes formed of a material selected from the group consisting of metallic borides, nitrides and silicides, with the proviso that the silicides do not include the silicides of Cr, Mo and W; whereby mercury wetting of the contacts is precluded, thereby avoiding undesired bridging of the contacts in the open position of the switch.

  6. MEMS switches having non-metallic crossbeams

    NASA Technical Reports Server (NTRS)

    Scardelletti, Maximillian C (Inventor)

    2009-01-01

    A RF MEMS switch comprising a crossbeam of SiC, supported by at least one leg above a substrate and above a plurality of transmission lines forming a CPW. Bias is provided by at least one layer of metal disposed on a top surface of the SiC crossbeam, such as a layer of chromium followed by a layer of gold, and extending beyond the switch to a biasing pad on the substrate. The switch utilizes stress and conductivity-controlled non-metallic thin cantilevers or bridges, thereby improving the RF characteristics and operational reliability of the switch. The switch can be fabricated with conventional silicon integrated circuit (IC) processing techniques. The design of the switch is very versatile and can be implemented in many transmission line mediums.

  7. Improving growth rate of microalgae in a 1191m(2) raceway pond to fix CO2 from flue gas in a coal-fired power plant.

    PubMed

    Cheng, Jun; Yang, Zongbo; Huang, Yun; Huang, Lei; Hu, Lizuo; Xu, Donghua; Zhou, Junhu; Cen, Kefa

    2015-08-01

    CO2 fixation between microalgal biomass and culture solution and the weight ratio of biomass consumption at nighttime to biomass growth at daytime were compared in an open raceway pond aerated with flue gas from a coal-fired power plant. Average daytime sunlight intensity and solution temperature were optimized to improve microalgal growth rate and to enhance the efficiency of CO2 fixation. When the average daytime solution temperature increased from 12 to 26°C, the rate of biomass consumption due to microalgal respiration at nighttime increased from 6.0 to 7.9g/m(2)/d, which was approximately 25% of the biomass growth rate at daytime. Furthermore, when the average daytime sunlight intensity increased from 39,900 to 88,300lux, CO2 fixation rate in the microalgal biomass increased from 18.4 to 40.7g/m(2)/d, which was approximately 1/3 of CO2 removal rate from flue gas by the microalgal culture system. PMID:25958147

  8. How to improve fertility of African soils? Leguminous fallows (Cameroon), addition of farmyard manure and mineral fertilizer (Kenya), organic residues management and introduction of N2 fixing species in forest plantations (Congo).

    NASA Astrophysics Data System (ADS)

    Koutika, Lydie-Stella; Mareschal, Louis; Mouanda, Cadeau; Epron, Daniel

    2014-05-01

    Most of African soils are inherently infertile and poor in nutrients mainly nitrogen and phosphorus. Several practices are used to improve soil fertility, increase productivity and ensure their sustainability. Soil fertility in the leguminous fallows was evaluated through particulate organic matter (POM), the more active part of soil organic matter (SOM) in Cameroon. The combination of mineral and organic (manure) fertilizers increased microbial P biomass allowing the release of P along the plant growing period in the Kenyan soils. Organic residues management and introduction of nitrogen fixing species (Acacia) were used to improve soil fertility and sustain forest productivity on the coastal plains of Congo. SOM fractionation was made under Pueraria, Mucuna fallows and natural regrowth mainly Chromolaena and under 3 forest plantation treatments installed in previous savanna: 1) no input, 2) normal input, and 3) double input of organic residues. Microbial P biomass and sequential P fractionation were evaluated in high and low P fixing soils. N, C, available P and pH were determined on soil sampled in acacia (100A), eucalypt (100E) and mixed-species (50A:50E) stands. N and P were determined in aboveground litters and in leaves, bark and wood of trees. The two leguminous fallows increased N content in POM fractions i.e., N >1% for Pueraria and Mucuna against N<1% for natural regrowth in the 0-0.10m depth, probably through N input from N2 fixation from the atmosphere (Cameroon).The addition of mineral fertilizers and farmyard manure increases P biomass (4.8 after 2 weeks to 15.2 after 16 weeks), and then decreased to 9.7 mg P g-1 soil (week 32). It also changes the P Hedley fractions partition in the high P fixing Kenyan soil (0-0.10m). After two rotations (14 years), SOM mineralization was the highest in the double input of organic residues treatment (low coarse POM 5.6 g kg-1 of soil and high organo-mineral fraction (OMF) 115 g kg-1 of soil). The introduction of A

  9. Composite Thermal Switch

    NASA Technical Reports Server (NTRS)

    McDonald, Robert; Brawn, Shelly; Harrison, Katherine; O'Toole, Shannon; Moeller, Michael

    2011-01-01

    Lithium primary and lithium ion secondary batteries provide high specific energy and energy density. The use of these batteries also helps to reduce launch weight. Both primary and secondary cells can be packaged as high-rate cells, which can present a threat to crew and equipment in the event of external or internal short circuits. Overheating of the cell interior from high current flows induced by short circuits can result in exothermic reactions in lithium primary cells and fully charged lithium ion secondary cells. Venting of the cell case, ejection of cell components, and fire have been reported in both types of cells, resulting from abuse, cell imperfections, or faulty electronic control design. A switch has been developed that consists of a thin layer of composite material made from nanoscale particles of nickel and Teflon that conducts electrons at room temperature and switches to an insulator at an elevated temperature, thus interrupting current flow to prevent thermal runaway caused by internal short circuits. The material is placed within the cell, as a thin layer incorporated within the anode and/or the cathode, to control excess currents from metal-to-metal or metal-to-carbon shorts that might result from cell crush or a manufacturing defect. The safety of high-rate cells is thus improved, preventing serious injury to personnel and sensitive equipment located near the battery. The use of recently available nanoscale particles of nickel and Teflon permits an improved, homogeneous material with the potential to be fine-tuned to a unique switch temperature, sufficiently below the onset of a catastrophic chemical reaction. The smaller particles also permit the formation of a thinner control film layer (<50 m), which can be incorporated into commercial high-rate lithium primary and secondary cells. The innovation permits incorporation in current lithium and lithium-ion cell designs with a minimal impact on cell weight and volume. The composite thermal

  10. Packet switching in 1990's

    NASA Astrophysics Data System (ADS)

    Rybczynski, A.

    The author assesses wide-area networking end-user needs as they evolve into the 1990s. He then turns to the network operator environment, both public and private, by examining service evolution trends. The author concludes with an assessment of how packet switching services and technologies are evolving to continue to match the identified market requirements, with specific emphasis on Northern Telecom's DPN Data Networking System. Key evolving DPN capabilities include the introduction of the high-end DPN100 30-kb/s switch, a variety of access options including ISDN (integrated services digital network) packet mode services, higher throughput virtual circuits, megabit trunking for improved network throughput and end-user transit delay, and SNA session switching, the latter being an example of adding value to packet networking through communication processing.

  11. Fixing Dataset Search

    NASA Technical Reports Server (NTRS)

    Lynnes, Chris

    2014-01-01

    Three current search engines are queried for ozone data at the GES DISC. The results range from sub-optimal to counter-intuitive. We propose a method to fix dataset search by implementing a robust relevancy ranking scheme. The relevancy ranking scheme is based on several heuristics culled from more than 20 years of helping users select datasets.

  12. Future Fixed Target Facilities

    SciTech Connect

    Melnitchouk, Wolodymyr

    2009-01-01

    We review plans for future fixed target lepton- and hadron-scattering facilities, including the 12 GeV upgraded CEBAF accelerator at Jefferson Lab, neutrino beam facilities at Fermilab, and the antiproton PANDA facility at FAIR. We also briefly review recent theoretical developments which will aid in the interpretation of the data expected from these facilities.

  13. Heat switches for ADRs

    NASA Astrophysics Data System (ADS)

    DiPirro, M. J.; Shirron, P. J.

    2014-07-01

    Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

  14. Heat Switches for ADRs

    NASA Technical Reports Server (NTRS)

    DiPirro, M. J.; Shirron, P. J.

    2014-01-01

    Heat switches are key elements in the cyclic operation of Adiabatic Demagnetization Refrigerators (ADRs). Several of the types of heat switches that have been used for ADRs are described in this paper. Key elements in selection and design of these switches include not only ON/OFF switching ratio, but also method of actuation, size, weight, and structural soundness. Some of the trade-off are detailed in this paper.

  15. Optical Plasmonic Switch based on Graphene

    NASA Astrophysics Data System (ADS)

    Moon, Kyungsun; Park, Suk-Young

    2015-03-01

    We have studied an electro-optical plasmonic waveguide, which controls the transmission of incident light by switching the coupling of the surface plasmon polariton (SPP) localized on graphene. It has been previously shown that the propagation length of the SPP localized on the copper surface can be effectively reduced by a factor of two or three by applying external bias potential. In our study, we have demonstrated that the propagation length of the SPP localized on graphene can be dramatically reduced by a factor of ten or so and the wavelength of SPP can be reduced by several hundredths of that of the incident light as well. We have also investigated the effect of scattering times of graphene and active Si layer on switching line shape. Switching occurs upon varying the carrier density of Si layer by ?n/nc ~1% in the vicinity of switching region. For a fixed bias voltage applied just below the critical value, signal laser beam shone into the metal nano-particles may increase the carrier density as such, which will induce switching. This may help develop an all-optical nano-scale plasmonic switch. This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (NRF-2012R1A1A2006927).

  16. Apollo Ring Optical Switch

    SciTech Connect

    Maestas, J.H.

    1987-03-01

    An optical switch was designed, built, and installed at Sandia National Laboratories in Albuquerque, New Mexico, to facilitate the integration of two Apollo computer networks into a single network. This report presents an overview of the optical switch as well as its layout, switch testing procedure and test data, and installation.

  17. Triggered plasma opening switch

    SciTech Connect

    Mendel, C W

    1988-02-23

    A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.

  18. Triggered plasma opening switch

    DOEpatents

    Mendel, Clifford W.

    1988-01-01

    A triggerable opening switch for a very high voltage and current pulse includes a transmission line extending from a source to a load and having an intermediate switch section including a plasma for conducting electrons between transmission line conductors and a magnetic field for breaking the plasma conduction path and magnetically insulating the electrons when it is desired to open the switch.

  19. X-ray crystal structures of Escherichia coli RNA polymerase with switch region binding inhibitors enable rational design of squaramides with an improved fraction unbound to human plasma protein

    PubMed Central

    Molodtsov, Vadim; Fleming, Paul R.; Eyermann, Charles J.; Ferguson, Andrew D.; Foulk, Melinda A.; McKinney, David C.; Masse, Craig E.; Buurman, Ed T.; Murakami, Katsuhiko S.

    2015-01-01

    Squaramides constitute a novel class of RNA polymerase inhibitors of which genetic evidence and computational modeling previously have suggested an inhibitory mechanism mediated by binding to the RNA polymerase switch region. An iterative chemistry program increased the fraction unbound to human plasma protein from below minimum detection levels, i.e. <1%, to 4~6%, while retaining biochemical potency. Since in vitro antimicrobial activity against an efflux-negative strain of Haemophilus influenzae was 4~8-fold higher, the combined improvement was at least 20~60-fold. Co-crystal structures of Escherichia coli RNA polymerase with two key squaramides showed displacement of the switch 2, predicted to interfere with the conformational change of clamp domain and/or with binding of non-template DNA, a mechanism akin to that of natural product myxopyronin. Furthermore, the structures confirmed the chemical features required for biochemical potency. The terminal isoxazole and benzyl rings bind into distinct relatively narrow, hydrophobic pockets and both are required for biochemical potency. In contrast, the linker composed of squarate and piperidine accesses different conformations in their respective co-crystal structures with RNA polymerase, reflecting its main role of proper orientation of the aforementioned terminal rings. These observations further explain the tolerance of hydrophilic substitutions in the linker region that was exploited to improve the fraction unbound to human plasma protein while retaining biochemical potency. PMID:25798859

  20. Wide Bandgap Extrinsic Photoconductive Switches

    NASA Astrophysics Data System (ADS)

    Sullivan, James Stephen

    Wide Bandgap Extrinsic Photoconductive Switches Semi-insulating Gallium Nitride, 4H and 6H Silicon Carbide are attractive materials for compact, high voltage, extrinsic, photoconductive switches due to their wide bandgap, high dark resistance, high critical electric field strength and high electron saturation velocity. These wide bandgap semiconductors are made semi-insulating by the addition of vanadium (4H and 6H-SiC) and iron (2H-GaN) impurities that form deep acceptors. These deep acceptors trap electrons donated from shallow donor impurities. The electrons can be optically excited from these deep acceptor levels into the conduction band to transition the wide bandgap semiconductor materials from a semi-insulating to a conducting state. Extrinsic photoconductive switches with opposing electrodes have been constructed using vanadium compensated 6H-SiC and iron compensated 2H-GaN. These extrinsic photoconductive switches were tested at high voltage and high power to determine if they could be successfully used as the closing switch in compact medical accelerators. The successful development of a vanadium compensated, 6H-SiC extrinsic photoconductive switch for use as a closing switch for compact accelerator applications was realized by improvements made to the vanadium, nitrogen and boron impurity densities. The changes made to the impurity densities were based on the physical intuition outlined and simple rate equation models. The final 6H-SiC impurity 'recipe' calls for vanadium, nitrogen and boron densities of 2.5 e17 cm-3, 1.25e17 cm-3 and ≤ 1e16 cm-3, respectively. This recipe was originally developed to maximize the quantum efficiency of the vanadium compensated 6H-SiC, while maintaining a thermally stable semi-insulating material. The rate equation models indicate that, besides increasing the quantum efficiency, the impurity recipe should be expected to also increase the carrier recombination time. Three generations of 6H-SiC materials were tested. The

  1. Oxygen-induced graphitization of amorphous carbon deposit on ohmic switch contacts improves their electrical conductivity and protects them from wear

    NASA Astrophysics Data System (ADS)

    Brand, Vitali; de Boer, Maarten P.

    2014-09-01

    There has been a resurgence of interest in developing ohmic switches to complement transistors in order to address challenges associated with electrical current leakage and lowering power consumption. A critical limitation is the reliability of their electrical contacts, which are prone to wear and hydrocarbon-induced contamination. These phenomena progressively inhibit signal transmission, eventually leading to device failure. We report on progress made towards converting the contamination into a highly conductive material. We show that Pt-coated microswitch contacts operating in the presence of O2 experience limited contaminant accumulation even in hydrocarbon-rich environments. We then demonstrate that devices that have experienced contamination can recover their original performance when operated in a clean N2:O2 environment. Auger and Raman spectroscopy indicate that this resistance recovery is associated with the structural transformation of the contaminant as opposed to its removal and that the transformed contaminant may shield the Pt coating from wear.

  2. Shuttle-promoted nano-mechanical current switch

    SciTech Connect

    Song, Taegeun Kiselev, Mikhail N.; Gorelik, Leonid Y.; Shekhter, Robert I.; Kikoin, Konstantin

    2015-09-21

    We investigate electron shuttling in three-terminal nanoelectromechanical device built on a movable metallic rod oscillating between two drains. The device shows a double-well shaped electromechanical potential tunable by a source-drain bias voltage. Four stationary regimes controllable by the bias are found for this device: (i) single stable fixed point, (ii) two stable fixed points, (iii) two limit cycles, and (iv) single limit cycle. In the presence of perpendicular magnetic field, the Lorentz force makes possible switching from one electromechanical state to another. The mechanism of tunable transitions between various stable regimes based on the interplay between voltage controlled electromechanical instability and magnetically controlled switching is suggested. The switching phenomenon is implemented for achieving both a reliable active current switch and sensoring of small variations of magnetic field.

  3. REMOTE CONTROLLED SWITCHING DEVICE

    DOEpatents

    Hobbs, J.C.

    1959-02-01

    An electrical switching device which can be remotely controlled and in which one or more switches may be accurately operated at predetermined times or with predetermined intervening time intervals is described. The switching device consists essentially of a deck, a post projecting from the deck at right angles thereto, cam means mounted for rotation around said posts and a switch connected to said deck and actuated by said cam means. Means is provided for rotating the cam means at a constant speed and the switching apparatus is enclosed in a sealed container with external adjusting means and electrical connection elements.

  4. PPARγ Ligands Switched High Fat Diet-Induced Macrophage M2b Polarization toward M2a Thereby Improving Intestinal Candida Elimination

    PubMed Central

    Olagnier, David; Bernad, José; Perez, Laurence; Burcelin, Rémy; Valentin, Alexis; Auwerx, Johan; Pipy, Bernard; Coste, Agnès

    2010-01-01

    Obesity is associated with a chronic low-grade inflammation that predisposes to insulin resistance and the development of type 2 diabetes. In this metabolic context, gastrointestinal (GI) candidiasis is common. We recently demonstrated that the PPARγ ligand rosiglitazone promotes the clearance of Candida albicans through the activation of alternative M2 macrophage polarization. Here, we evaluated the impact of high fat diet (HFD)-induced obesity and the effect of rosiglitazone (PPARγ ligand) or WY14643 (PPARα ligand) both on the phenotypic M1/M2 polarization of peritoneal and cecal tissue macrophages and on the outcome of GI candidiasis. We demonstrated that the peritoneal macrophages and the cell types present in the cecal tissue from HF fed mice present a M2b polarization (TNF-αhigh, IL-10high, MR, Dectin-1). Interestingly, rosiglitazone induces a phenotypic M2b-to-M2a (TNF-αlow, IL-10low, MRhigh, Dectin-1high) switch of peritoneal macrophages and of the cells present in the cecal tissue. The incapacity of WY14643 to switch this polarization toward M2a state, strongly suggests the specific involvement of PPARγ in this mechanism. We showed that in insulin resistant mice, M2b polarization of macrophages present on the site of infection is associated with an increased susceptibility to GI candidiasis, whereas M2a polarization after rosiglitazone treatment favours the GI fungal elimination independently of reduced blood glucose. In conclusion, our data demonstrate a dual benefit of PPARγ ligands because they promote mucosal defence mechanisms against GI candidiasis through M2a macrophage polarization while regulating blood glucose level. PMID:20877467

  5. Subpicosecond photonic switching based on bacteriorhodopsin

    NASA Astrophysics Data System (ADS)

    Ormos, Pal; Fabian, Laszlo; Heiner, Zsuzsanna; Mero, Mark; Kiss, Miklos; Wolff, Elmar; Osvay, Karoly; der, Andras

    2011-03-01

    All-optical data processing is the most promising approach for further improvement in data trafficking. We present a subpicosecond photonic switch where the active role is performed by the chromoprotein bacteriorhodopsin. The changes in the refractive index that accompany the steps of the photocycle of bacteriorhodopsin are used for all optical switching in appropriate integrated optical devices. We use grating coupled planar waveguides and the coupling is modulated by the light induced refractive index changes of bacteriorhodopsin. The switching is demonstrated in ultrafast pump-probe experiments. Different transitions of the photocycle are explored for switching applications. We show that by using the bR to I transition subpicosecond switching can be readily achieved. The approach is a basis for protein-based integrated optical devices, eventually leading to a conceptual revolution in telecommunications technologies.

  6. Simulations of a plasma flow switch

    SciTech Connect

    Buff, J.; Frese, M.H.; Giancola, A.J.; Peterkin, R.E.; Roderick, N.F.

    1987-12-01

    In a portion of the experimental program using the SHIVA Star capacitor bank at the Air Force Weapons Laboratory (AFWL), a cylindrical foil load is imploded using an inductive store and a plasma flow switch. The authors performed a number of two-dimensional simulations of the switch and load using the MHD code MACH2. In addition to explaining the data from the first series of experiments, the simulations led to design modifications of the basic plasma flow switch that resulted in improved current delivery and in enhanced radiation yield. The key modification was closing portions of the vane structure. The switch must be sealed shut or else substantial current will flow in the diffuse gas that is ablated from the walls of the switch barrel.

  7. A solid-state dielectric elastomer switch for soft logic

    NASA Astrophysics Data System (ADS)

    Chau, Nixon; Slipher, Geoffrey A.; O'Brien, Benjamin M.; Mrozek, Randy A.; Anderson, Iain A.

    2016-03-01

    In this paper, we describe a stretchable solid-state electronic switching material that operates at high voltage potentials, as well as a switch material benchmarking technique that utilizes a modular dielectric elastomer (artificial muscle) ring oscillator. The solid-state switching material was integrated into our oscillator, which self-started after 16 s and performed 5 oscillations at a frequency of 1.05 Hz with 3.25 kV DC input. Our materials-by-design approach for the nickel filled polydimethylsiloxane based switch has resulted in significant improvements over previous carbon grease-based switches in four key areas, namely, sharpness of switching behavior upon applied stretch, magnitude of electrical resistance change, ease of manufacture, and production rate. Switch lifetime was demonstrated to be in the range of tens to hundreds of cycles with the current process. An interesting and potentially useful strain-based switching hysteresis behavior is also presented.

  8. Flexibility in task switching by monolinguals and bilinguals*

    PubMed Central

    WISEHEART, MELODY; VISWANATHAN, MYTHILI; BIALYSTOK, ELLEN

    2015-01-01

    Many bilinguals routinely switch between their languages, yet mixed evidence exists about the transfer of language switching skills to broader domains that require attentional control such as task switching. Monolingual and bilingual young adults performed a nonverbal task-switching paradigm in which they viewed colored pictures of animals and indicated either the animal or its color in response to a cue. Monolinguals and bilinguals performed similarly when switching between tasks (local switch cost) in a mixed-task block, but bilinguals demonstrated a smaller mixing effect (global switch cost) than monolinguals, indicating better ability to reconfigure stimulus–response associations. These results suggest that regular practice using multiple languages confers a broader executive function advantage shown as improved flexibility in task switching. PMID:26877705

  9. Optimization of health-care organization and perceived improvement of patient comfort by switching from intra-venous BU four-times-daily infusions to a once-daily administration scheme in adult hematopoietic stem cell recipients.

    PubMed

    Xhaard, A; Rzepecki, P; Valcarcel, D; Santarone, S; Fürst, S; Serrano, D; De Angelis, G; Krüger, W; Scheid, C

    2014-04-01

    Previous studies have shown an equivalent pharmacokinetic profile between four-times-daily (4QD) and once-daily (QD) administration of intra-venous (IV) BU, without increased toxicity. We assess the impact of a switch in IV BU from a 4QD to a QD schedule, in terms of health-care organization, staff working conditions, quality of care dispensed and perceived patient comfort. Clinicians, nurses and pharmacists from nine allogeneic transplantation units in five European countries were interviewed face to face. Overall perception of QD versus 4QD BU was very positive. Both administration schemes were evaluated to be equally efficaciousZ. QD BU was perceived to be safer and more convenient. Clinicians and nurses perceived that patient comfort was improved, due to fewer complications associated with repeated infusions, and avoiding night infusions associated with stress, anxiety and decreased quality of sleep. Switching from 4QD to QD BU had a significant impact on health-care organization, with a better integration in the overall management and usual timelines in the pharmacies and transplantation units. Time spent to prepare and administer BU was significantly reduced, leading to potential financial savings that merit further assessment and would be of particular interest in the current economic climate. PMID:24419513

  10. Precise Point Positioning with Partial Ambiguity Fixing.

    PubMed

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  11. Precise Point Positioning with Partial Ambiguity Fixing

    PubMed Central

    Li, Pan; Zhang, Xiaohong

    2015-01-01

    Reliable and rapid ambiguity resolution (AR) is the key to fast precise point positioning (PPP). We propose a modified partial ambiguity resolution (PAR) method, in which an elevation and standard deviation criterion are first used to remove the low-precision ambiguity estimates for AR. Subsequently the success rate and ratio-test are simultaneously used in an iterative process to increase the possibility of finding a subset of decorrelated ambiguities which can be fixed with high confidence. One can apply the proposed PAR method to try to achieve an ambiguity-fixed solution when full ambiguity resolution (FAR) fails. We validate this method using data from 450 stations during DOY 021 to 027, 2012. Results demonstrate the proposed PAR method can significantly shorten the time to first fix (TTFF) and increase the fixing rate. Compared with FAR, the average TTFF for PAR is reduced by 14.9% for static PPP and 15.1% for kinematic PPP. Besides, using the PAR method, the average fixing rate can be increased from 83.5% to 98.2% for static PPP, from 80.1% to 95.2% for kinematic PPP respectively. Kinematic PPP accuracy with PAR can also be significantly improved, compared to that with FAR, due to a higher fixing rate. PMID:26067196

  12. Class E/F switching power amplifiers

    NASA Technical Reports Server (NTRS)

    Hajimiri, Seyed-Ali (Inventor); Aoki, Ichiro (Inventor); Rutledge, David B. (Inventor); Kee, Scott David (Inventor)

    2004-01-01

    The present invention discloses a new family of switching amplifier classes called class E/F amplifiers. These amplifiers are generally characterized by their use of the zero-voltage-switching (ZVS) phase correction technique to eliminate of the loss normally associated with the inherent capacitance of the switching device as utilized in class-E amplifiers, together with a load network for improved voltage and current wave-shaping by presenting class-F.sup.-1 impedances at selected overtones and class-E impedances at the remaining overtones. The present invention discloses a several topologies and specific circuit implementations for achieving such performance.

  13. Effective switching frequency multiplier inverter

    SciTech Connect

    Su, Gui-Jia; Peng, Fang Z.

    2007-08-07

    A switching frequency multiplier inverter for low inductance machines that uses parallel connection of switches and each switch is independently controlled according to a pulse width modulation scheme. The effective switching frequency is multiplied by the number of switches connected in parallel while each individual switch operates within its limit of switching frequency. This technique can also be used for other power converters such as DC/DC, AC/DC converters.

  14. Thermally actuated thermionic switch

    DOEpatents

    Barrus, D.M.; Shires, C.D.

    1982-09-30

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  15. Thermally actuated thermionic switch

    DOEpatents

    Barrus, Donald M.; Shires, Charles D.

    1988-01-01

    A thermally actuated thermionic switch which responds to an increase of temperature by changing from a high impedance to a low impedance at a predictable temperature set point. The switch has a bistable operation mode switching only on temperature increases. The thermionic material may be a metal which is liquid at the desired operation temperature and held in matrix in a graphite block reservoir, and which changes state (ionizes, for example) so as to be electrically conductive at a desired temperature.

  16. AC magnetohydrodynamic microfluidic switch

    SciTech Connect

    Lemoff, A V; Lee, A P

    2000-03-02

    A microfluidic switch has been demonstrated using an AC Magnetohydrodynamic (MHD) pumping mechanism in which the Lorentz force is used to pump an electrolytic solution. By integrating two AC MHD pumps into different arms of a Y-shaped fluidic circuit, flow can be switched between the two arms. This type of switch can be used to produce complex fluidic routing, which may have multiple applications in {micro}TAS.

  17. Solid state switch

    DOEpatents

    Merritt, Bernard T.; Dreifuerst, Gary R.

    1994-01-01

    A solid state switch, with reverse conducting thyristors, is designed to operate at 20 kV hold-off voltage, 1500 A peak, 1.0 .mu.s pulsewidth, and 4500 pps, to replace thyratrons. The solid state switch is more reliable, more economical, and more easily repaired. The switch includes a stack of circuit card assemblies, a magnetic assist and a trigger chassis. Each circuit card assembly contains a reverse conducting thyristor, a resistor capacitor network, and triggering circuitry.

  18. Fixed and Sunk Costs Revisited.

    ERIC Educational Resources Information Center

    Wang, X. Henry; Yang, Bill Z.

    2001-01-01

    Attempts to clarify the concepts of, and the link between, fixed costs and sunk costs. Argues that the root of confusion is the inconsistency in defining the term fixed costs. Consistently defines fixed and sunk costs, and describes how instructors must teach under these definitions. (RLH)

  19. Reusable fast opening switch

    DOEpatents

    Van Devender, J.P.; Emin, D.

    1983-12-21

    A reusable fast opening switch for transferring energy, in the form of a high power pulse, from an electromagnetic storage device such as an inductor into a load. The switch is efficient, compact, fast and reusable. The switch comprises a ferromagnetic semiconductor which undergoes a fast transition between conductive and metallic states at a critical temperature and which undergoes the transition without a phase change in its crystal structure. A semiconductor such as europium rich europhous oxide, which undergoes a conductor to insulator transition when it is joule heated from its conductor state, can be used to form the switch.

  20. Scheduling and performance evaluation of high line-rate space-wavelength routed switch for datacenter

    NASA Astrophysics Data System (ADS)

    Huang, Qirui; Cheng, Xiaofei; Zhou, Luying

    In this paper, we investigate the performance of a high line-rate space-wavelength routed switch to assess its potential for use in large-scale datacenters. A scheduling technique is introduced for the switch to address challenges in packet arbitration taking into account a high line rate and large port-count. The traffic performance in terms of packet loss rate and latency of the switch is evaluated by simulations under various traffic patterns. The results show that even under burst traffic conditions, the packet loss rate and latency of the switch are almost independent of the switch size, which indicates that the switch could support a large number of nodes for switching without significant performance deterioration for both fixed and variable packet sizes. It is also found that a slight increase in the number of tunable transmitters in each node could lead to a great reduction in packet loss and latency for the switch.

  1. Melanin Index in Assessing the Treatment Efficacy of 1064 nm Q Switched Nd-Yag Laser in Nevus of Ota

    PubMed Central

    Sethuraman, Gomathy; Sharma, Vinod K; Sreenivas, Vishnubhatla

    2013-01-01

    Background: Q-switched neodymium-yttrium aluminium-garnet (Q switched Nd-Yag) laser has been used in the treatment of nevus of Ota in all skin types with variable success rate. Data with an objective assessment parameter to this laser treatment is lacking. Objective: To evaluate the utility of melanin index in assessing the treatment response and also determine the efficacy and safety of the Q-switched Nd-Yag laser (1064-nm) in the treatment of nevus of Ota in Fitzpatrick skin types IV and V. Materials and Methods: A total of 35 patients treated with Nd-Yag laser were studied. The objective improvement (pigment clearance) was determined by melanin index from two fixed points: A1, 2 cm below the pupil at the mid pupillary line (when the gaze is fixed); A2, the most prominent part of zygoma. The melanin index in these two areas was recorded as M1 and M2, respectively. The subjective clinical improvement was determined by the physician and the patient global assessment score. Results: The mean baseline melanin indices M1 and M2 were 59.54 ± 9.72 and 59.02 ± 9.16, respectively. At the last visit the mean M1 and M2 decreased to 53.8 ± 8.55 (P < 0.001) and 54.13 ± 6.01 (P < 0.001), respectively. Patient and the physician global assessment score showed that 26 (74.3%) and 20 (57.14%) patients, respectively, had >50% pigment clearance. Conclusion: The melanin index, a simple non-invasive parameter is useful in assessing the treatment response more objectively. The 1064-nm Q-switched Nd-Yag laser offers good improvement in patients with nevus of Ota in darker skin types IV/V. PMID:24470713

  2. Asymmetrical Switch Costs in Children

    ERIC Educational Resources Information Center

    Ellefson, Michelle R.; Shapiron, Laura R.; Chater, Nick

    2006-01-01

    Switching between tasks produces decreases in performance as compared to repeating the same task. Asymmetrical switch costs occur when switching between two tasks of unequal difficulty. This asymmetry occurs because the cost is greater when switching to the less difficult task than when switching to the more difficult task. Various theories about…

  3. Multi-mode sliding mode control for precision linear stage based on fixed or floating stator

    NASA Astrophysics Data System (ADS)

    Fang, Jiwen; Long, Zhili; Wang, Michael Yu; Zhang, Lufan; Dai, Xufei

    2016-02-01

    This paper presents the control performance of a linear motion stage driven by Voice Coil Motor (VCM). Unlike the conventional VCM, the stator of this VCM is regulated, which means it can be adjusted as a floating-stator or fixed-stator. A Multi-Mode Sliding Mode Control (MMSMC), including a conventional Sliding Mode Control (SMC) and an Integral Sliding Mode Control (ISMC), is designed to control the linear motion stage. The control is switched between SMC and IMSC based on the error threshold. To eliminate the chattering, a smooth function is adopted instead of a signum function. The experimental results with the floating stator show that the positioning accuracy and tracking performance of the linear motion stage are improved with the MMSMC approach.

  4. Apparatus for fixing latency

    DOEpatents

    Hall, David R.; Bartholomew, David B.; Moon, Justin; Koehler, Roger O.

    2009-09-08

    An apparatus for fixing computational latency within a deterministic region on a network comprises a network interface modem, a high priority module and at least one deterministic peripheral device. The network interface modem is in communication with the network. The high priority module is in communication with the network interface modem. The at least one deterministic peripheral device is connected to the high priority module. The high priority module comprises a packet assembler/disassembler, and hardware for performing at least one operation. Also disclosed is an apparatus for executing at least one instruction on a downhole device within a deterministic region, the apparatus comprising a control device, a downhole network, and a downhole device. The control device is near the surface of a downhole tool string. The downhole network is integrated into the tool string. The downhole device is in communication with the downhole network.

  5. Fixed Access Network Sharing

    NASA Astrophysics Data System (ADS)

    Cornaglia, Bruno; Young, Gavin; Marchetta, Antonio

    2015-12-01

    Fixed broadband network deployments are moving inexorably to the use of Next Generation Access (NGA) technologies and architectures. These NGA deployments involve building fiber infrastructure increasingly closer to the customer in order to increase the proportion of fiber on the customer's access connection (Fibre-To-The-Home/Building/Door/Cabinet… i.e. FTTx). This increases the speed of services that can be sold and will be increasingly required to meet the demands of new generations of video services as we evolve from HDTV to "Ultra-HD TV" with 4k and 8k lines of video resolution. However, building fiber access networks is a costly endeavor. It requires significant capital in order to cover any significant geographic coverage. Hence many companies are forming partnerships and joint-ventures in order to share the NGA network construction costs. One form of such a partnership involves two companies agreeing to each build to cover a certain geographic area and then "cross-selling" NGA products to each other in order to access customers within their partner's footprint (NGA coverage area). This is tantamount to a bi-lateral wholesale partnership. The concept of Fixed Access Network Sharing (FANS) is to address the possibility of sharing infrastructure with a high degree of flexibility for all network operators involved. By providing greater configuration control over the NGA network infrastructure, the service provider has a greater ability to define the network and hence to define their product capabilities at the active layer. This gives the service provider partners greater product development autonomy plus the ability to differentiate from each other at the active network layer.

  6. RF Reference Switch for Spaceflight Radiometer Calibration

    NASA Technical Reports Server (NTRS)

    Knuble, Joseph

    2013-01-01

    The goal of this technology is to provide improved calibration and measurement sensitivity to the Soil Moisture Active Passive Mission (SMAP) radiometer. While RF switches have been used in the past to calibrate microwave radiometers, the switch used on SMAP employs several techniques uniquely tailored to the instrument requirements and passive remote-sensing in general to improve radiometer performance. Measurement error and sensitivity are improved by employing techniques to reduce thermal gradients within the device, reduce insertion loss during antenna observations, increase insertion loss temporal stability, and increase rejection of radar and RFI (radio-frequency interference) signals during calibration. The two legs of the single-pole double-throw reference switch employ three PIN diodes per leg in a parallel-shunt configuration to minimize insertion loss and increase stability while exceeding rejection requirements at 1,413 MHz. The high-speed packaged diodes are selected to minimize junction capacitance and resistance while ensuring the parallel devices have very similar I-V curves. Switch rejection is improved by adding high-impedance quarter-wave tapers before and after the diodes, along with replacing the ground via of one diode per leg with an open circuit stub. Errors due to thermal gradients in the switch are reduced by embedding the 50-ohm reference load within the switch, along with using a 0.25-in. (approximately equal to 0.6-cm) aluminum prebacked substrate. Previous spaceflight microwave radiometers did not embed the reference load and thermocouple directly within the calibration switch. In doing so, the SMAP switch reduces error caused by thermal gradients between the load and switch. Thermal issues are further reduced by moving the custom, highspeed regulated driver circuit to a physically separate PWB (printed wiring board). Regarding RF performance, previous spaceflight reference switches have not employed high-impedance tapers to improve

  7. Manually operated coded switch

    DOEpatents

    Barnette, Jon H.

    1978-01-01

    The disclosure relates to a manually operated recodable coded switch in which a code may be inserted, tried and used to actuate a lever controlling an external device. After attempting a code, the switch's code wheels must be returned to their zero positions before another try is made.

  8. Reflective HTS switch

    DOEpatents

    Martens, Jon S.; Hietala, Vincent M.; Hohenwarter, Gert K. G.

    1994-01-01

    A HTS switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time.

  9. Reflective HTS switch

    DOEpatents

    Martens, J.S.; Hietala, V.M.; Hohenwarter, G.K.G.

    1994-09-27

    A HTS (High Temperature Superconductor) switch includes a HTS conductor for providing a superconducting path for an electrical signal and an serpentine wire actuator for controllably heating a portion of the conductor sufficiently to cause that portion to have normal, and not superconducting, resistivity. Mass of the portion is reduced to decrease switching time. 6 figs.

  10. Multidimensional set switching.

    PubMed

    Hahn, Sowon; Andersen, George J; Kramer, Arthur F

    2003-06-01

    The present study examined the organization of preparatory processes that underlie set switching and, more specifically, switch costs. On each trial, subjects performed one of two perceptual judgment tasks, color or shape discrimination. Subjects also responded with one of two different response sets. The task set and/or the response set switched from one to the other after 2-6 repeated trials. Response set, task set, and double set switches were performed in both blocked and randomized conditions. Subjects performed with short (100-msec) and long (800-msec) preparatory intervals. Task and response set switches had an additive effect on reaction times (RTs) in the blocked condition. Such a pattern of results suggests a serial organization of preparatory processes when the nature of switches is predictable. However, task and response set switches had an underadditive effect on RTs in the random condition when subjects performed with a brief cue-to-target interval. This pattern of results suggests overlapping task and response set preparation. These findings are discussed in terms of strategic control of preparatory processes in set switching. PMID:12921431

  11. A Novel Molecular Switch

    PubMed Central

    Daber, Robert; Lewis, Mitchell

    2009-01-01

    Transcriptional regulation is a fundamental process for regulating the flux of all metabolic pathways. For the last several decades, the lac operon has served as a valuable model for studying transcription. More recently, the switch that controls the operon has also been successfully adapted to function in mammalian cells. Here we describe how, using directed evolution, we have created a novel switch that recognizes an asymmetric operator sequence. The new switch has a repressor with altered headpiece domains for operator recognition, and a redesigned dimer interface to create a heterodimeric repressor. Quite unexpectedly, the heterodimeric switch functions better than the natural system. It can repress more tightly than the naturally occurring switch of the lac operon; it is less leaky and can be induced more efficiently. Ultimately these novel repressors could be evolved to recognize eukaryotic promoters and used to regulate gene expression in mammalian systems. PMID:19540845

  12. Erected mirror optical switch

    DOEpatents

    Allen, James J.

    2005-06-07

    A microelectromechanical (MEM) optical switching apparatus is disclosed that is based on an erectable mirror which is formed on a rotatable stage using surface micromachining. An electrostatic actuator is also formed on the substrate to rotate the stage and mirror with a high angular precision. The mirror can be erected manually after fabrication of the device and used to redirect an incident light beam at an arbitrary angel and to maintain this state in the absence of any applied electrical power. A 1.times.N optical switch can be formed using a single rotatable mirror. In some embodiments of the present invention, a plurality of rotatable mirrors can be configured so that the stages and mirrors rotate in unison when driven by a single micromotor thereby forming a 2.times.2 optical switch which can be used to switch a pair of incident light beams, or as a building block to form a higher-order optical switch.

  13. Nanoscale memristive radiofrequency switches

    NASA Astrophysics Data System (ADS)

    Pi, Shuang; Ghadiri-Sadrabadi, Mohammad; Bardin, Joseph C.; Xia, Qiangfei

    2015-06-01

    Radiofrequency switches are critical components in wireless communication systems and consumer electronics. Emerging devices include switches based on microelectromechanical systems and phase-change materials. However, these devices suffer from disadvantages such as large physical dimensions and high actuation voltages. Here we propose and demonstrate a nanoscale radiofrequency switch based on a memristive device. The device can be programmed with a voltage as low as 0.4 V and has an ON/OFF conductance ratio up to 1012 with long state retention. We measure the radiofrequency performance of the switch up to 110 GHz and demonstrate low insertion loss (0.3 dB at 40 GHz), high isolation (30 dB at 40 GHz), an average cutoff frequency of 35 THz and competitive linearity and power-handling capability. Our results suggest that, in addition to their application in memory and computing, memristive devices are also a leading contender for radiofrequency switch applications.

  14. Switch on, switch off: stiction in nanoelectromechanical switches.

    PubMed

    Wagner, Till J W; Vella, Dominic

    2013-07-12

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the 'ON' state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between 'free', 'pinned' and 'clamped' states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed. PMID:23759938

  15. Switch on, switch off: stiction in nanoelectromechanical switches

    NASA Astrophysics Data System (ADS)

    Wagner, Till J. W.; Vella, Dominic

    2013-07-01

    We present a theoretical investigation of stiction in nanoscale electromechanical contact switches. We develop a mathematical model to describe the deflection of a cantilever beam in response to both electrostatic and van der Waals forces. Particular focus is given to the question of whether adhesive van der Waals forces cause the cantilever to remain in the ‘ON’ state even when the electrostatic forces are removed. In contrast to previous studies, our theory accounts for deflections with large slopes (i.e. geometrically nonlinear). We solve the resulting equations numerically to study how a cantilever beam adheres to a rigid electrode: transitions between ‘free’, ‘pinned’ and ‘clamped’ states are shown to be discontinuous and to exhibit significant hysteresis. Our findings are compared to previous results from linearized models and the implications for nanoelectromechanical cantilever switch design are discussed.

  16. [Fixed-drug combinations for hypertension].

    PubMed

    Sato, Nobuyuki; Hasebe, Naoyuki

    2014-08-01

    The recent guidelines for the treatment of hypertension recommend a fixed-dose combination (polypill) therapy to achieve optimal blood pressure (BP) control. Among them, angiotensin receptor blockers (ARBs) with calcium channel blockers (CCBs) or diuretics are the representative recommended combination since each drug has evidence of reducing cardiovascular events. Recent studies using ambulatory blood pressure monitoring have also suggested that the fixed-dose ARB-based combination therapies with either CCBs or diuretics are well tolerated and effectively lower the BP throughout a 24-hour interval by their long-acting half-lives, nighttime BP lowering effect and improving adherence. It will become more important to use these fixed-dose antihypertensive drugs adequately for controlling the 24-hour blood pressure. PMID:25167756

  17. HTS-based switched filter banks and delay lines

    SciTech Connect

    Martens, J.S.; Hietala, V.M.; Ginley, D.S.; Tigges, C.P.; Plut, T.A.; Truman, J.K.; Track, E.K.; Young, K.H.; Young, R.T.

    1992-09-01

    For a number of communications and other applications, switched filter banks (some channelizers) and switched delay lines (phase shifters) are extremely useful since YBaCuO and TlCaBaCuO filters and delay lines have shown significant performance enhancements over their conventional counterparts, a purely superconducting version of the switched assemblies could result in additional improvements. A thermal switch has been developed that provides good isolation and insertion loss with adequate switching times to allow a monolithic approach to the switched lines and filter banks. Filter banks in the 8--11 GHz range have been demonstrated with insertion losses < 1 dB and out-of-band rejection greater than a package-limited 50 dB. Switched delay lines have been fabricated with insertion losses less than 0.3 dB/bit and peak phase deviations from linearity of less than 5 degrees over 30 GHz bandwidths.

  18. HTS-based switched filter banks and delay lines

    SciTech Connect

    Martens, J.S.; Hietala, V.M.; Ginley, D.S.; Tigges, C.P.; Plut, T.A. ); Truman, J.K. ); Track, E.K. ); Young, K.H.; Young, R.T. )

    1992-01-01

    For a number of communications and other applications, switched filter banks (some channelizers) and switched delay lines (phase shifters) are extremely useful since YBaCuO and TlCaBaCuO filters and delay lines have shown significant performance enhancements over their conventional counterparts, a purely superconducting version of the switched assemblies could result in additional improvements. A thermal switch has been developed that provides good isolation and insertion loss with adequate switching times to allow a monolithic approach to the switched lines and filter banks. Filter banks in the 8--11 GHz range have been demonstrated with insertion losses < 1 dB and out-of-band rejection greater than a package-limited 50 dB. Switched delay lines have been fabricated with insertion losses less than 0.3 dB/bit and peak phase deviations from linearity of less than 5 degrees over 30 GHz bandwidths.

  19. Contraceptive method switching among American female adolescents, 1979.

    PubMed

    Hirsch, M B; Zelnik, M

    1985-01-01

    Better knowledge about contraceptive use in adolescents is needed if pregnancy prevention is to be improved. Data from the 1979 National Survey of Young Women were used to examine method switching once contraceptive use had begun among 449 never-pregnant young women who reported premarital intercourse more than once. Bivariate chi2 tests and multivariate logit regression were used to examine factors related to switching in four analyses: overall switching; switching among those with one intercourse partner; and switching from nonmedical and medical methods separately. Frequency of intercourse and type of first method had an interactive effect on switching; length of exposure to switching, type of relationship, and reason for choosing the first method were also significant. These results suggest that providers and educators should consider the circumstances under which contraceptive methods are chosen and used by young women when counseling them as to what method may be best for them. PMID:3965412

  20. Towards single molecule switches.

    PubMed

    Zhang, Jia Lin; Zhong, Jian Qiang; Lin, Jia Dan; Hu, Wen Ping; Wu, Kai; Xu, Guo Qin; Wee, Andrew T S; Chen, Wei

    2015-05-21

    The concept of using single molecules as key building blocks for logic gates, diodes and transistors to perform basic functions of digital electronic devices at the molecular scale has been explored over the past decades. However, in addition to mimicking the basic functions of current silicon devices, molecules often possess unique properties that have no parallel in conventional materials and promise new hybrid devices with novel functions that cannot be achieved with equivalent solid-state devices. The most appealing example is the molecular switch. Over the past decade, molecular switches on surfaces have been intensely investigated. A variety of external stimuli such as light, electric field, temperature, tunneling electrons and even chemical stimulus have been used to activate these molecular switches between bistable or even multiple states by manipulating molecular conformations, dipole orientations, spin states, charge states and even chemical bond formation. The switching event can occur either on surfaces or in break junctions. The aim of this review is to highlight recent advances in molecular switches triggered by various external stimuli, as investigated by low-temperature scanning tunneling microscopy (LT-STM) and the break junction technique. We begin by presenting the molecular switches triggered by various external stimuli that do not provide single molecule selectivity, referred to as non-selective switching. Special focus is then given to selective single molecule switching realized using the LT-STM tip on surfaces. Single molecule switches operated by different mechanisms are reviewed and discussed. Finally, molecular switches embedded in self-assembled monolayers (SAMs) and single molecule junctions are addressed. PMID:25757483

  1. Application of repumping laser in optical switching

    NASA Astrophysics Data System (ADS)

    Ray, Ayan; Ali, Md. Sabir; Chakrabarti, Alok

    2014-08-01

    The application of electromagnetically induced transparency (EIT) in high speed optical switching has remained as a key topic in research related to all optical switching. Demonstration of optical switching through EIT realized under ladder (Ξ) level coupling has been reported earlier. Due to narrow linewidth (ГEIT) and low coherent dephasing rate (γ) the EIT needs to be prepared only once to demonstrate such switching action. However, in a Ξ system the EIT is accompanied with double resonance optical pumping (DROP) signal, which is limited by spontaneous decay (Г) rates. It has been shown by our group that the simultaneous presence of DROP-EIT combination paves the way for executing a kind of slow-fast switching action. However the focus always remain on improving the modulation depth in such type of coherence assisted switch. Here we report a possible way to improve modulation depth by using an additional (named 'repumping' after convention used in laser cooling experiments) laser in the Ξ system. The 5S1/2→5P3/2→5D5/2 level coupling scheme of 87Rb atom is used in the current experiment.

  2. Intrinsic noise in systems with switching environments

    NASA Astrophysics Data System (ADS)

    Hufton, Peter G.; Lin, Yen Ting; Galla, Tobias; McKane, Alan J.

    2016-05-01

    We study individual-based dynamics in finite populations, subject to randomly switching environmental conditions. These are inspired by models in which genes transition between on and off states, regulating underlying protein dynamics. Similarly, switches between environmental states are relevant in bacterial populations and in models of epidemic spread. Existing piecewise-deterministic Markov process approaches focus on the deterministic limit of the population dynamics while retaining the randomness of the switching. Here we go beyond this approximation and explicitly include effects of intrinsic stochasticity at the level of the linear-noise approximation. Specifically, we derive the stationary distributions of a number of model systems, in good agreement with simulations. This improves existing approaches which are limited to the regimes of fast and slow switching.

  3. MACRA: Fix or Folly?

    PubMed

    Levine, Steve

    2016-01-01

    The Texas Medical Association has made recommendations to improve the Centers for Medicare & Medicaid Services' proposed rule to implement the Medicare Access and CHIP Reauthorization Act (MACRA), which results in numerous compliance and administrative hassles. PMID:27622892

  4. Optical packet switching

    NASA Astrophysics Data System (ADS)

    Shekel, Eyal; Ruschin, Shlomo; Majer, Daniel; Levy, Jeff; Matmon, Guy; Koenigsberg, Lisa; Vecht, Jacob; Geron, Amir; Harlavan, Rotem; Shfaram, Harel; Arbel, Arnon; McDermott, Tom; Brewer, Tony

    2005-02-01

    We report here a scalable, multichassis, 6.3 terabit core router, which utilizes our proprietary optical switch. The router is commercially available and deployed in several customer sites. Our solution combines optical switching with electronic routing. An internal optical packet switching network interconnects the router"s electronic line cards, where routing and buffering functions take place electronically. The system architecture and performance will be described. The optical switch is based on Optical Phased Array (OPA) technology. It is a 64 x 64, fully non-blocking, optical crossbar switch, capable of switching in a fraction of a nanosecond. The basic principles of operation will be explained. Loss and crosstalk results will be presented, as well as the results of BER measurements of a 160 Gbps transmission through one channel. Basic principles of operation and measured results will be presented for the burst-mode-receivers, arbitration algorithm and synchronization. Finally, we will present some of our current research work on a next-generation optical switch. The technological issues we have solved in our internal optical packet network can have broad applicability to any global optical packet network.

  5. Optical Circuit Switched Protocol

    NASA Technical Reports Server (NTRS)

    Monacos, Steve P. (Inventor)

    2000-01-01

    The present invention is a system and method embodied in an optical circuit switched protocol for the transmission of data through a network. The optical circuit switched protocol is an all-optical circuit switched network and includes novel optical switching nodes for transmitting optical data packets within a network. Each optical switching node comprises a detector for receiving the header, header detection logic for translating the header into routing information and eliminating the header, and a controller for receiving the routing information and configuring an all optical path within the node. The all optical path located within the node is solely an optical path without having electronic storage of the data and without having optical delay of the data. Since electronic storage of the header is not necessary and the initial header is eliminated by the first detector of the first switching node. multiple identical headers are sent throughout the network so that subsequent switching nodes can receive and read the header for setting up an optical data path.

  6. Development of a 1×2 piezoelectric optical fiber switch

    NASA Astrophysics Data System (ADS)

    Leung, M.; Yue, J.; Razak, K. A.; Haemmerle, E.; Hodgson, M.; Gao, W.

    2008-03-01

    This paper presents the design, fabrication and performance of a 1×2 piezoelectric optical switch. The optical switch is developed based on the concept that the input fiber is directly moved by the deflection of a piezoelectric tube actuator. The piezoelectric tube actuator used in this switch is manufactured through an electrophoretic deposition process. The tube is inexpensive to produce and compact in size with high mechanical performance. It has a maximum deflection of 30μm which is capable to actuate the input fiber for switching. The multimode fiber optical switch has been successfully assembled. To reduce the misalignment loss between the fibers, the output fibers are precisely aligned in silicon vgrooves. Different components are bonded with low shrinkage adhesive in order to minimize their position inaccuracy. The performance characteristics of the optical switch have been measured, with an insertion loss of 1dB, crosstalk of -45dB and switching speed from 5 to 10ms. The switch also shows good reliability and requires small driving power. The development of multimode optical switch prototypes proves that the idea of piezoelectric switching is feasible. Further developments include the improvement of switching performance, reduction of the prototype size and the fabrication of multiple output prototypes.

  7. Improvements in access to malaria treatment in Tanzania after switch to artemisinin combination therapy and the introduction of accredited drug dispensing outlets - a provider perspective

    PubMed Central

    2010-01-01

    Background To improve access to treatment in the private retail sector a new class of outlets known as accredited drug dispensing outlets (ADDO) was created in Tanzania. Tanzania changed its first-line treatment for malaria from sulphadoxine-pyrimethamine (SP) to artemether-lumefantrine (ALu) in 2007. Subsidized ALu was made available in both health facilities and ADDOs. The effect of these interventions on access to malaria treatment was studied in rural Tanzania. Methods The study was carried out in the villages of Kilombero and Ulanga Demographic Surveillance System (DSS) and in Ifakara town. Data collection consisted of: 1) yearly censuses of shops selling drugs; 2) collection of monthly data on availability of anti-malarials in public health facilities; and 3) retail audits to measure anti-malarial sales volumes in all public, mission and private outlets. The data were complemented with DSS population data. Results Between 2004 and 2008 access to malaria treatment greatly improved and the number of anti-malarial treatment doses dispensed increased by 78%. Particular improvements were observed in the availability (from 0.24 shops per 1,000 people in 2004 to 0.39 in 2008) and accessibility (from 71% of households within 5 km of a shop in 2004 to 87% in 2008) of drug shops. Despite no improvements in affordability this resulted in an increase of the market share from 49% of anti-malarial sales 2005 to 59% in 2008. The change of treatment policy from SP to ALu led to severe stock-outs of SP in health facilities in the months leading up to the introduction of ALu (only 40% months in stock), but these were compensated by the wide availability of SP in shops. After the introduction of ALu stock levels of the drug were relatively high in public health facilities (over 80% months in stock), but the drug could only be found in 30% of drug shops and in no general shops. This resulted in a low overall utilization of the drug (19% of all anti-malarial sales) Conclusions

  8. Drug discrimination under a concurrent fixed-ratio fixed-ratio schedule.

    PubMed Central

    McMillan, D E; Li, M

    1999-01-01

    Pigeons were trained to discriminate 5.0 mg/kg pentobarbital from saline under a two-key concurrent fixed-ratio 10 fixed-ratio 40 schedule of food presentation, in which the fixed-ratio component with the lower response requirement was programmed to reinforce responding on one key after drug administration (pentobarbital-biased key) and on the other key after saline administration (saline-biased key). After responding stabilized, pigeons averaged 98% of their responses on the pentobarbital-biased key during training sessions preceded by pentobarbital, and they averaged 90% of their responses on the saline-biased key during training sessions preceded by saline. In test sessions preceded by doses of pentobarbital, chlordiazepoxide, or ethanol, pigeons switched from responding on the saline-biased key at low doses to responding on the pentobarbital-biased key at higher doses (the dose-response curve was quantal). High doses of phencyclidine produced responding on both keys, whereas pigeons responded almost exclusively on the saline-biased key after all doses of methamphetamine. These and previous experiments using concurrent reinforcement schedules to study drug discrimination illustrate that the schedule of reinforcement is an important determinant of the shape of dose-effect curves in drug-discrimination experiments. PMID:10503298

  9. Photoconductive switch package

    DOEpatents

    Ca[rasp, George J

    2013-10-22

    A photoconductive switch is formed of a substrate that has a central portion of SiC or other photoconductive material and an outer portion of cvd-diamond or other suitable material surrounding the central portion. Conducting electrodes are formed on opposed sides of the substrate, with the electrodes extending beyond the central portion and the edges of the electrodes lying over the outer portion. Thus any high electric fields produced at the edges of the electrodes lie outside of and do not affect the central portion, which is the active switching element. Light is transmitted through the outer portion to the central portion to actuate the switch.

  10. Electromechanical magnetization switching

    SciTech Connect

    Chudnovsky, Eugene M.; Jaafar, Reem

    2015-03-14

    We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.