18,999 research outputs found
Probing of Barrier Induced Deviations in Current-Voltage Characteristics of Polymer Devices by Impedance Spectroscopy
No full textTemperature dependent current-voltage measurements have been performed on poly(3-methylthiophene) based devices in metal/polymer/metal geometry in temperature range 90-300 K. Space charge limited current (SCLC) controlled by exponentially distributed traps is observed at all the measured temperatures at intermediate voltage range. At higher voltages, trap-free SCLC is observed at 90 K only while slope less than 2 is observed at higher temperatures which is quiet unusual in polymer devices. Impedance measurements were performed at different bias voltages. The unusual behavior observed in current-voltage characteristics is explained by Cole-Cole plot which gives the signature of interface dipole on electrode/polymer interface. Two relaxation mechanisms are obtained from the real part of impedance vs frequency spectra which confirms the interface related phenomena in the devic
A new luminescence immunoassay for thyrotropin using coated tubes: evaluation and comparison with immunoradiometric assay
No full textA recently available chemiluminescence immunoassay (LIA-MAT) for TSH, set up by Byk-Sangtec Diagnostica, has been evaluated and compared with IRMA methods. The system LIA-MAT uses two monoclonal antibodies: one coated on tubes and the other labelled with isoluminol. To compute the within-assay precision profile, we estimated the response error relationship from all the duplicates (420) of eleven experiments. The CV of the response was 4-5% from the maximal response until 10,000 RLU (corresponding to about 1 microIU/ml); in the lower response range the CV worsened up to 8%. The sensitivity, derived from the precision profile, was 0.052 microIU/ml similar to that found in IRMA-MAT (0.044 microIU/ml); the working range extended from 0.33 to 100 microIU/ml. Results from LIA-MAT in the concentration range 1-30 microIU/ml were compared with the consensus mean produced by users of IRMA methods (IRMA-MAT, IRMA-Behring, Maiaclone Serono) participating in an inter-laboratory survey; a good correlation with IRMA techniques was found. The distribution of TSH determinations produced by LIA-MAT on 62 low concentration sample (less than 0.3 microIU/ml) from patients unresponsive to TRH test, was found similar to that observed for the kit IRMA Boots-Celltech assumed as reference
Recent technological advancements in laparoscopic surgical instruments
No full textLaparoscopy was a progressive step to advancing surgical procedures as it minimised the scars left on the body after surgery, compared to traditional open surgery. Many years later, single-incision laparoscopic surgery (SILS) was created where, instead of having multiple incisions, only one incision is made or multiple small incisions in one location. SILS, or laparoendoscopic single-site surgery (LESS), may produce lesser scars but drawbacks for the surgeons are still present. This paper aims to present related literature of the recent technological developments in laparoscopic tools and procedure particularly in the vision system, handheld instruments. Tech advances in LESS will also be shown. Furthermore, this review intends to give an update on what has been going on in the surgical robot market and state which companies are interested and are developing robotic systems for commercial use to challenge Intuitive Surgical\u27s da Vinci Surgical System that currently dominates the market. © 2018 Author(s). Published by AIP Publishing
Versatile DAC-less successive approximation ADC architecture for medium speed data acquisition
No full textImplementation of the DAC is usually the bottleneck in designing a SAR ADC. Here an innovative DAC-less SAR (DLSAR) ADC architecture is presented which alleviates some drawbacks of the conventional SAR counterpart. The proposed DLSAR binary search algorithm is comprised of two arithmetic operations of division-by-two and subtraction to emulate the DAC function. The hardware of the DLSAR ADC is implemented using ordinary circuit building blocks of a SAR ADC but with less complexity and more robustness against PVT variations as DAC is removed. The developed DLSAR architecture is versatile so that the converter hardware could be readily reconfigured for different sampling rates and resolutions. Based on post-layout simulations in 0.18 μm CMOS process, the designed 8-bit DLSAR ADC consumes 150 μW of power at 2 MS/s including the asynchronous control logic circuit. The SFDR of the converter is up to 62 dB and the ENOB reaches 7.8 bits while it remains above 7.5 bits across most PVT corners without calibration. Also, by reconfiguring the DLSAR ADC to 9-bit resolution at 1 MS/s, the ENOB is generally around 8.2 bits achieving a scaled figure-of-merit (SFoM) better than 3.0 Ç/c-s.Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.Bio-Electronic
Effects of biased irradiation on charge trapping in HfO<inf>2</inf> dielectric thin films
Get PDF© 2017 Author(s). This paper reports the low-dose-rate radiation response of Al-HfO 2 /SiO 2 -Si MOS devices, in which the gate dielectric was formed by atomic layer deposition (ALD) with 5-nm equivalent oxide thickness. The degradation of the devices was characterized by a pulse capacitance-voltage (CV) and on-site radiation response technique under continuous gamma (γ) ray exposure at a relatively low dose rate of 0.116 rad (HfO 2 )/s. Compared with conventional CV measurements, the proposed measurements extract significant variations of flat-band voltage shift of the hafnium based MOS devices. The large flat-band voltage shift is mainly attributed to the radiation-induced oxide trapped charges, which are not readily compensated by bias-induced charges produced over the measurement timescales (for timescales less than 5 ms). A negative flat-band voltage shift up to -1.02 V was observed under a positive biased irradiation with the total dose up to 40 krad (HfO 2 ) and with the electric field of 0.5 MV/cm. This is attributed to net positive charge generation in the HfO 2 oxide layer. The generated charges are transported towards the HfO 2 /SiO 2 interface, and then form effective trapped holes in the HfO 2 . Similarly, a positive flat-band voltage shift up to 1.1 V was observed from irradiation under negative bias with an electric field of -0.5 MV/cm. The positive shift is mainly due to the accumulation of trapped electrons. Analyses of the experimental results suggest that both hole and electron trapping can dominate the radiation response performance of the HfO 2 -based MOS devices depending upon the applied bias. It was also found there was no distinct border traps with irradiation in all cases
Valutazione delle caratteristiche analitiche di un nuovo metodo di dosaggio del BNP
No full textEvaluation of the analytical characteristics of a new method for determination of BNP.
Recent studies demonstrated that there are marked differences in analytical performances and results obtained with different methods for BNP assay. The aim of this study is to evaluate the analytic performance and results obtained with a novel BNP assay using the platform AIA 2000 Tosoh Bioscience. The novel method for BNP
tested in the present study, named ST AIA-PACK BNP, is a two-site immunoenzymometric assay. The BNP assay uses a combination of two monoclonal antibodies and a fluorescent detection. The limits of blank (LoB) and detection (LoD) for BNP assay were determined according to the CLSI EP17-A protocol. As a result, the calculated LoB and LoD values were 2.6 ng/L and 5.4 ng/L, respectively. The assay reproducibility was evaluated in accordance with the CLSI EP5-A2
protocol by repeatedly measuring 3 different EDTA plasma samples for consecutive 20 working days, containing on average 8.70 ng/L, 21.72 ng/L, and 38.72 ng/L of BNP, respectively; CV values between 19.4% and 5.0% were obtained. The between-runs imprecision profile was performed by repeatedly measuring in 20 different runs 9 EDTA blood sample, with concentration from 5 ng/L to 778 ng/L, collected from healthy subjects and patients with cardiac disease. The calculated limits of quantitation (LoQ) at 20% CV and 10% CV were 9 and 30 ng/L of BNP, respectively. The results obtained with the new BNP Tosoh method was compared with those found with the TRIAGE Beckman-Coulter. A very close linear regression was found when the BNP values were measured with Tosoh and Beckman-Coulter methods in 133 EDTA plasma samples of healthy subjects and cardiac patients. However the Tosoh method showed on average a significant negative bias (i.e., underestimation) of BNP values compared to Beckman-Coulter of -40.0%±8.8% (mean±SD, p<0.0001). A significant correlation was also found between the BNP and NT-proBNP values, respectively measured with AIA Tosoh and ECLIA Roche methods, although weaker than that obtained comparing the two BNP assays. These data suggest that the ST AIA-PACK BNP assay has reproducibility and analytic sensitivity similar to the common automated methods commercially available at present time. In particular, the AIA method measures the recommended cut-off (i.e., 100 ng/L) by international guidelines with an imprecision less than 5%. These data also suggest that clinicians should be carefull when comparing results from different laboratories, which use different BNP
assays
Minimum radiative heat-load aerocapture guidance with attitude-kinematics constraints
No full textTo maximize the payload mass, an aerocapture trajectory should be flown in such a way that both the final ΔV and the total heat load are minimized. At very high velocities, the heating due to radiation of high temperature gases in the shock-layer exceeds the heat due to convection. For some aerocapture missions, such a heat load can be 15 times larger than the heat load due to convection. Thus, convective heat load may in some cases be neglected. It is analytically proven that radiative heat load is minimized by the same trajectory that Minimizes The Final Δ V: a bang-bang trajectory, with full lift-up, full lift-down commands. Next, a novel guidance that plans a bang-bang trajectory with constraints in the attitude kinematics is introduced. This allows for achieving an optimal trajectory with only one parameter to be tuned. For the case studied, values of ΔV as low as 100 m/s can be ensured for entry angles between -6° and -5° and a large spectrum of perturbations; with the same guidance, radiative heat load is reduced by up to 20% with respect to traditional aerocapture-guidance methods. Finally, a lateral guidance that makes use of information on the final inclination of the predicted trajectory is introduced. Such guidance allows for very high accuracy in the inclination requirements with only two reversals, and also requires only a single parameter to be tuned. Depending on the tuning, a maximum inclination error of less than 0.1° can be guaranteed.Astrodynamics & Space Mission
Role of lichens in granite weathering in cold and arid environments of continental Antarctica
No full textThe mechanical and chemical effects of lichens on the outer and inner surfaces of tafoni features were investigated through a multidisciplinary approach at two locations (Oasi 74°42'S, 164°07'E, 40-250 m a.s.l.; Mount Keinath, 74°32'S; 163°58'E; 850 m a.s.l.) close to the Italian Antarctic station (Mario Zucchelli). Outer tafoni roof surfaces show low values of effective porosity coupled with pervasive hyphal penetration and an extensive reddish-brown weathering rind. Inner tafoni surfaces show higher values of effective porosity, which correspond with an almost absent weathering rind and low hyphal penetration. Our observations indicate that: (a) iron oxy-hydroxides, particularly concentrated where hyphal patches and bundles contact biotite, consist of hematite; (b) the microcosms of lichen hyphae and their precipitates fill voids to form case hardening on outer surfaces; and (c) on inner surfaces biological action is less active, most likely because of more intense thermal stress and salt action
Design of a clinical trial using generalized pairwise comparisons to test a less intensive treatment regimen
No full textShowing "similar efficacy" of a less intensive treatment typically requires a non-inferiority trial. Yet such trials may be challenging to design and conduct. In acute promyelocytic leukemia, great progress has been achieved with the introduction of targeted therapies, but toxicity remains a major clinical issue. There is a pressing need to show the favorable benefit/risk of less intensive treatment regimens.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: This work was supported, in part, by the Government of Wallonia, Belgium (Grant No. BioWin Consortium
Agreement No. 7979)
The effect of demographic changes on saving for life cycle motives in developing countries
Get PDFIf developing countries follow the same paths that industrialized countries have followed, saving for retirement will initially become more important as the population growth rate declines. To calculate the potential importance of life-cycle savings (saving for retirement), the paper presents a simulation model that translates demographic projections into savings-rate projections. It simulated aggregate rates for life-cycle savings for Brazil, China, Korea, Mexico, Nigeria, Pakistan and Turkey. The savings rates increase 5 or 6 percentage points when the last baby boomers enter the work force and begin to save after their children leave home. The effect on life-cycle savings is dramatic; the effect on total savings rates which are often three or four times as high, is not. Simulated life-cycle savings rates peak at an absolute 10 percent or less in all cases. The patterns of these projections seem robust with regard to assumptions about productivity growth, interest rates, and age-specific participation in the labor force.Banks&Banking Reform,Environmental Economics&Policies,Economic Theory&Research,Health Monitoring&Evaluation,Inequality
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