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Sample records for high analytical sensitivity

  1. Conducting polymer nanofibers for high sensitivity detection of chemical analytes.

    Science.gov (United States)

    Kumar, Abhishek; Leshchiner, Ignaty; Nagarajan, Subhalakshmi; Nagarajan, Ramaswamy; Kumar, Jayant

    2008-03-01

    Possessing large surface area materials is vital for high sensitivity detection of analyte. We report a novel, inexpensive and simple technique to make high surface area sensing interfaces using electrospinning. Conducting polymers (CP) nanotubes were made by electrospinning a solution of a catalyst (ferric tosylate) along with poly (lactic acid), which is an environment friendly biodegradable polymer. Further vapor deposition polymerization of the monomer ethylenedioxy thiophene (EDOT) on the nanofiber surface yielded poly (EDOT) covered fibers. X-ray photo electron spectroscopy (XPS) study reveals the presence of PEDOT predominantly on the surface of nanofibers. Conducting nanotubes had been received by dissolving the polymer in the fiber core. By a similar technique we had covalently incorporated fluorescent dyes on the nanofiber surface. The materials obtained show promise as efficient sensing elements. UV-Vis characterization confirms the formation of PEDOT nanotubes and incorporation of chromophores on the fiber surface. The morphological characterization was carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM).

  2. European multicenter analytical evaluation of the Abbott ARCHITECT STAT high sensitive troponin I immunoassay

    DEFF Research Database (Denmark)

    Krintus, Magdalena; Kozinski, Marek; Boudry, Pascal

    2014-01-01

    high sensitive cardiac troponin I (hs-cTnI) assay and its 99th percentile upper reference limit (URL). METHODS: Laboratories from nine European countries evaluated the ARCHITECT STAT high sensitive troponin I (hs-TnI) immunoassay on the ARCHITECT i2000SR/i1000SR immunoanalyzers. Imprecision, limit...... hs-cTnI assay and contemporary cTnI assay at 99th percentile cut-off was found to be 95%. TnI was detectable in 75% and 57% of the apparently healthy population using the lower (1.1 ng/L) and upper (1.9 ng/L) limit of the LoD range provided by the ARCHITECT STAT hs-TnI package insert, respectively....... The 99th percentile values were gender dependent. CONCLUSIONS: The new ARCHITECT STAT hs-TnI assay with improved analytical features meets the criteria of high sensitive Tn test and will be a valuable diagnostic tool....

  3. High-sensitivity cardiac troponin assays: From improved analytical performance to enhanced risk stratification.

    Science.gov (United States)

    Kozinski, Marek; Krintus, Magdalena; Kubica, Jacek; Sypniewska, Grazyna

    2017-05-01

    Implementation of cardiac troponin (cTn) assays has revolutionized the diagnosis, risk stratification, triage and management of patients with suspected myocardial infarction (MI). The Universal Definition of MI brought about a shift in the diagnostics of MI, from an approach primarily based on electrocardiography (ECG) to one primarily based on biomarkers. Currently, detection of a rise and/or fall in concentration or activity of myocardial necrosis biomarkers, preferentially cTns, with at least one value above the 99th percentile upper reference limit (URL), is the essential component for the diagnosis of MI. High-sensitivity cardiac troponin (hs-cTn) assays with their superior analytical performance were designed to further facilitate clinical decision making. The ability of hs-cTn assays to detect measurable cTn concentrations in at least 50% of healthy individuals, along with their improved precision (expressed as coefficient of variation ≤10% at the 99th percentile URL) associated with increased recognition of changing values, leads to enhanced risk stratification of patients with suspected MI, and also enables them to be used as prognostic tools potentially useful in other patient subsets. In this comprehensive review, we aim to integrate updated laboratory and clinical knowledge regarding hs-cTn assays in order to promote their optimal use in daily practice. We primarily focus on the role of hs-cTn assays in patients with suspected MI, discussing recommended diagnostic algorithms and result interpretation. Emphasis is also placed on the release of cTns following myocardial injury, the characteristics of antibodies used in available cTn immunoassays, and analytical performance of hs-cTn assays. In this paper, we also review potential challenges related to the selection of a healthy reference population in determining 99th percentile values, biological variation of hs-cTns, inequality between hs-cTn assays, and outline the current status of c

  4. Quasi-analytical solutions of hybrid platform and the optimization of highly sensitive thin-film sensors for terahertz radiation

    CERN Document Server

    Tapsanit, Piyawath; Ishihara, Teruya; Otani, Chiko

    2016-01-01

    We present quasi-analytical solutions (QANS) of hybrid platform (HP) comprising metallic grating (MG) and stacked-dielectric layers for terahertz (THz) radiation. The QANS are validated by finite difference time domain simulation. It is found that the Wood anomalies induce the high-order spoof surface plasmon resonances in the HP. The QANS are applied to optimize new perfect absorber for THz sensing of large-area thin film with ultrahigh figure of merit reaching fifth order of magnitude for the film thickness 0.0001p (p: MG period). The first-order Wood's anomaly of the insulator layer and the Fabry-Perot in the slit's cavity account for the resonance of the perfect absorber. The QANS and the new perfect absorber may lead to highly sensitive and practical nano-film refractive index sensor for THz radiation.

  5. Enhanced fluorescence sensitivity by coupling yttrium-analyte complexes and three-way fast high-performance liquid chromatography data modeling

    Energy Technology Data Exchange (ETDEWEB)

    Alcaraz, Mirta R.; Culzoni, María J., E-mail: mculzoni@fbcb.unl.edu.ar; Goicoechea, Héctor C., E-mail: hgoico@fbcb.unl.edu.ar

    2016-01-01

    The present study reports a sensitive chromatographic method for the analysis of seven fluoroquinolones (FQs) in environmental water samples, by coupling yttrium-analyte complex and three-way chromatographic data modeling. This method based on the use of HPLC-FSFD does not require complex or tedious sample treatments or enrichment processes before the analysis, due to the significant fluorescence increments of the analytes reached by the presence of Y{sup 3+}. Enhancement achieved for the FQs signals obtained after Y{sup 3+} addition reaches 103- to 1743-fold. Prediction results corresponding to the application of MCR-ALS to the validation set showed relative error of prediction (REP%) values below 10% in all cases. A recovery study that includes the simultaneous determination of the seven FQs in three different environmental aqueous matrices was conducted. The recovery studies assert the efficiency and the accuracy of the proposed method. The LOD values calculated are in the order of part per trillion (below 0.5 ng mL{sup −1} for all the FQs, except for enoxacin). It is noteworthy to mention that the method herein proposed, which does not include pre-concentration steps, allows reaching LOD values in the same order of magnitude than those achieved by more sophisticated methods based on SPE and UHPLC-MS/MS. - Highlights: • Highly sensitive method for the analysis of seven fluoroquinolones. • Coupling of yttrium-analyte complex and three-way modeling. • Complex or tedious sample treatments or enrichment processes are nor required. • Accuracy on the quantitation of fluoroquinolones in real water river samples.

  6. Sensitive and rapid analytical method for the quantification of glucosamine in human plasma by ultra high performance liquid chromatography with tandem mass spectrometry.

    Science.gov (United States)

    Yang, Wen; Zheng, Xiaohong; Simpemba, Ernest; Ma, Pengcheng; Ding, Li

    2015-06-01

    A highly sensitive and rapid ultra high performance liquid chromatography with tandem mass spectrometry method has been developed and validated for the determination of glucosamine in human plasma using miglitol as the internal standard. Special attention was paid to achieve the high throughput and sensitivity of the established method, and the absence of a matrix effect on the analytes. The sample preparation procedure involved a simple deproteinization step. The chromatographic separation was achieved on a Waters ACQUITY HSS Cyano column using a mixture of acetonitrile/2 mM ammonium acetate solution containing 0.03% formic acid (80:20, v/v) as the mobile phase with a very short run time of 1.5 min. This method was validated over the concentration range of 10-3000 ng/mL for glucosamine. The intra- and inter-batch precision was glucosamine level in human plasma, which has not been reported in detail until now. The method was successfully applied to characterize the pharmacokinetic profile of glucosamine in healthy volunteers following a single oral administration of 750 or 1500 mg glucosamine hydrochloride.

  7. A new structure of photonic crystal fiber with high sensitivity, high nonlinearity, high birefringence and low confinement loss for liquid analyte sensing applications

    Directory of Open Access Journals (Sweden)

    Md. Faizul Huq Arif

    2017-02-01

    Full Text Available This paper proposes the design and optimization of microstructure optical fiber for liquid sensing applications. A number of propagation characteristics have been compared between two formations of hexagonal cladding of our proposed PCF structure. The core of the proposed PCF structure is designed with two rows of supplementary elliptical air holes. We investigate the performance of the designed PCFs for Ethanol as a liquid sample to be sensed. Numerical analysis is carried out by employing the full vectorial Finite Element Method (FEM to examine the modal birefringence, confinement loss, relative sensitivity and nonlinear coefficient of the proposed PCF structure.

  8. Strand Invasion Based Amplification (SIBA®: a novel isothermal DNA amplification technology demonstrating high specificity and sensitivity for a single molecule of target analyte.

    Directory of Open Access Journals (Sweden)

    Mark J Hoser

    Full Text Available Isothermal nucleic acid amplification technologies offer significant advantages over polymerase chain reaction (PCR in that they do not require thermal cycling or sophisticated laboratory equipment. However, non-target-dependent amplification has limited the sensitivity of isothermal technologies and complex probes are usually required to distinguish between non-specific and target-dependent amplification. Here, we report a novel isothermal nucleic acid amplification technology, Strand Invasion Based Amplification (SIBA. SIBA technology is resistant to non-specific amplification, is able to detect a single molecule of target analyte, and does not require target-specific probes. The technology relies on the recombinase-dependent insertion of an invasion oligonucleotide (IO into the double-stranded target nucleic acid. The duplex regions peripheral to the IO insertion site dissociate, thereby enabling target-specific primers to bind. A polymerase then extends the primers onto the target nucleic acid leading to exponential amplification of the target. The primers are not substrates for the recombinase and are, therefore unable to extend the target template in the absence of the IO. The inclusion of 2'-O-methyl RNA to the IO ensures that it is not extendible and that it does not take part in the extension of the target template. These characteristics ensure that the technology is resistant to non-specific amplification since primer dimers or mis-priming are unable to exponentially amplify. Consequently, SIBA is highly specific and able to distinguish closely-related species with single molecule sensitivity in the absence of complex probes or sophisticated laboratory equipment. Here, we describe this technology in detail and demonstrate its use for the detection of Salmonella.

  9. High-Sensitivity Spectrophotometry.

    Science.gov (United States)

    Harris, T. D.

    1982-01-01

    Selected high-sensitivity spectrophotometric methods are examined, and comparisons are made of their relative strengths and weaknesses and the circumstances for which each can best be applied. Methods include long path cells, noise reduction, laser intracavity absorption, thermocouple calorimetry, photoacoustic methods, and thermo-optical methods.…

  10. Highly Sensitive Optical Receivers

    CERN Document Server

    Schneider, Kerstin

    2006-01-01

    Highly Sensitive Optical Receivers primarily treats the circuit design of optical receivers with external photodiodes. Continuous-mode and burst-mode receivers are compared. The monograph first summarizes the basics of III/V photodetectors, transistor and noise models, bit-error rate, sensitivity and analog circuit design, thus enabling readers to understand the circuits described in the main part of the book. In order to cover the topic comprehensively, detailed descriptions of receivers for optical data communication in general and, in particular, optical burst-mode receivers in deep-sub-µm CMOS are presented. Numerous detailed and elaborate illustrations facilitate better understanding.

  11. On accuracy problems for semi-analytical sensitivity analyses

    DEFF Research Database (Denmark)

    Pedersen, P.; Cheng, G.; Rasmussen, John

    1989-01-01

    The semi-analytical method of sensitivity analysis combines ease of implementation with computational efficiency. A major drawback to this method, however, is that severe accuracy problems have recently been reported. A complete error analysis for a beam problem with changing length is carried ou...... pseudo loads in order to obtain general load equilibrium with rigid body motions. Such a method would be readily applicable for any element type, whether analytical expressions for the element stiffnesses are available or not. This topic is postponed for a future study....

  12. An analytic method for sensitivity analysis of complex systems

    Science.gov (United States)

    Zhu, Yueying; Wang, Qiuping Alexandre; Li, Wei; Cai, Xu

    2017-03-01

    Sensitivity analysis is concerned with understanding how the model output depends on uncertainties (variances) in inputs and identifying which inputs are important in contributing to the prediction imprecision. Uncertainty determination in output is the most crucial step in sensitivity analysis. In the present paper, an analytic expression, which can exactly evaluate the uncertainty in output as a function of the output's derivatives and inputs' central moments, is firstly deduced for general multivariate models with given relationship between output and inputs in terms of Taylor series expansion. A γ-order relative uncertainty for output, denoted by Rvγ, is introduced to quantify the contributions of input uncertainty of different orders. On this basis, it is shown that the widely used approximation considering the first order contribution from the variance of input variable can satisfactorily express the output uncertainty only when the input variance is very small or the input-output function is almost linear. Two applications of the analytic formula are performed to the power grid and economic systems where the sensitivities of both actual power output and Economic Order Quantity models are analyzed. The importance of each input variable in response to the model output is quantified by the analytic formula.

  13. Strand Invasion Based Amplification (SIBA®): A Novel Isothermal DNA Amplification Technology Demonstrating High Specificity and Sensitivity for a Single Molecule of Target Analyte

    OpenAIRE

    Mark J Hoser; Mansukoski, Hannu K.; Morrical, Scott W.; Kevin E. Eboigbodin

    2014-01-01

    Isothermal nucleic acid amplification technologies offer significant advantages over polymerase chain reaction (PCR) in that they do not require thermal cycling or sophisticated laboratory equipment. However, non-target-dependent amplification has limited the sensitivity of isothermal technologies and complex probes are usually required to distinguish between non-specific and target-dependent amplification. Here, we report a novel isothermal nucleic acid amplification technology, Strand Invas...

  14. A new and consistent parameter for measuring the quality of multivariate analytical methods: Generalized analytical sensitivity.

    Science.gov (United States)

    Fragoso, Wallace; Allegrini, Franco; Olivieri, Alejandro C

    2016-08-24

    Generalized analytical sensitivity (γ) is proposed as a new figure of merit, which can be estimated from a multivariate calibration data set. It can be confidently applied to compare different calibration methodologies, and helps to solve literature inconsistencies on the relationship between classical sensitivity and prediction error. In contrast to the classical plain sensitivity, γ incorporates the noise properties in its definition, and its inverse is well correlated with root mean square errors of prediction in the presence of general noise structures. The proposal is supported by studying simulated and experimental first-order multivariate calibration systems with various models, namely multiple linear regression, principal component regression (PCR) and maximum likelihood PCR (MLPCR). The simulations included instrumental noise of different types: independently and identically distributed (iid), correlated (pink) and proportional noise, while the experimental data carried noise which is clearly non-iid.

  15. An analytic method for sensitivity analysis of complex systems

    CERN Document Server

    Zhu, Yueying; Li, Wei; Cai, Xu

    2016-01-01

    Sensitivity analysis is concerned with understanding how the model output depends on uncertainties (variances) in inputs and then identifies which inputs are important in contributing to the prediction imprecision. Uncertainty determination in output is the most crucial step in sensitivity analysis. In the present paper, an analytic expression, which can exactly evaluate the uncertainty in output as a function of the output's derivatives and inputs' central moments, is firstly deduced for general multivariate models with given relationship between output and inputs in terms of Taylor series expansion. A $\\gamma$-order relative uncertainty for output, denoted by $\\mathrm{R^{\\gamma}_v}$, is introduced to quantify the contributions of input uncertainty of different orders. On this basis, it is shown that the widely used approximation considering the first order contribution from the variance of input variable can satisfactorily express the output uncertainty only when the input variance is very small or the inpu...

  16. Analytical challenges in characterization of high purity materials

    Indian Academy of Sciences (India)

    K L Ramakumar

    2005-07-01

    Available analytical literature reveals that it is possible to identify a lot of procedures to carry out any determination using a plethora of analytical techniques. The fundamental analytical requirements for realizing the desired and acceptable information from a chemical analysis are representative nature of the sample, precision, accuracy, selectivity and sensitivity. These decide, to a larger extent, the selection of the most appropriate methodology in order to obtain chemical information from a system. A number of analytical methodologies are being used in the author’s laboratory for carrying out trace elemental analysis as a part of chemical quality control. Quite a good number of analytical challenges with specific reference to the characterization of high purity materials of relevance to nuclear technology were addressed and methodologies were developed for trace elemental analysis of both metallic and non-metallic constituents. A brief review of these analytical challenges and the analytical methodologies developed and also the future needs of analytical chemist are presented in this paper.

  17. An analytical high value target acquisition model

    OpenAIRE

    Becker, Kevin J.

    1986-01-01

    Approved for public release; distribution is unlimited An Analytical High Value Target (HVT) acquisition model is developed for a generic anti-ship cruise missile system. the target set is represented as a single HVT within a field of escorts. The HVT's location is described by a bivariate normal probability distribution. the escorts are represented by a spatially homogeneous Poisson random field surrounding the HVT. Model output consists of the probability that at least one missile of...

  18. High-Sensitivity Magnetization Measurements

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The three most common instruments for high-sensitivity magnetization measurements (the vibrating-sample magnetometer, the alternating gradient magnetometer, and the SQUID magne tometer) are described and their limiting sensitivities are discussed. The advantages and disad vantages of each are described. Magnetometers using micro-machined force detectors are briefly mentioned.

  19. Analytic central path, sensitivity analysis and parametric linear programming

    NARCIS (Netherlands)

    A.G. Holder; J.F. Sturm; S. Zhang (Shuzhong)

    1998-01-01

    textabstractIn this paper we consider properties of the central path and the analytic center of the optimal face in the context of parametric linear programming. We first show that if the right-hand side vector of a standard linear program is perturbed, then the analytic center of the optimal face

  20. Analytic central path, sensitivity analysis and parametric linear programming

    OpenAIRE

    A.G. Holder; Sturm, J.F.; Zhang, Shuzhong

    1998-01-01

    textabstractIn this paper we consider properties of the central path and the analytic center of the optimal face in the context of parametric linear programming. We first show that if the right-hand side vector of a standard linear program is perturbed, then the analytic center of the optimal face is one-side differentiable with respect to the perturbation parameter. In that case we also show that the whole analytic central path shifts in a uniform fashion. When the objective vector is pertur...

  1. Quantification of furanic derivatives in fortified wines by a highly sensitive and ultrafast analytical strategy based on digitally controlled microextraction by packed sorbent combined with ultrahigh pressure liquid chromatography.

    Science.gov (United States)

    Perestrelo, Rosa; Silva, Catarina L; Câmara, José S

    2015-02-13

    /MS) and ages. The obtained results revealed the analytical strategy as a suitable tool which combines sensitivity, effectiveness, reduced analysis time and simple analytical procedure. Principal component analysis (PCA) suggested that fortified wines can be organized based on their age on PC1, which are mainly characterized by 5HMF.

  2. 高敏感方法检测心肌肌钙蛋白T的分析性能评价%The analytical performance assessment of high-sensitivity cardiac troponin T reference intervals investigation

    Institute of Scientific and Technical Information of China (English)

    宋凌燕; 吴炯; 宋斌斌; 邵文琦; 张春燕; 王蓓丽; 郭玮; 潘柏申

    2010-01-01

    Objective To assess the analytical performance of hs-cTnT and biological variations in healthy population as well as establish hs-cTnT reference intervals. Methods The serum samples from 100 acute myocardial infraction patients and 474 apparently healthy subjects were collected. The functional sensitivity,within- and between-run imprecision were determined. The hs-cTnT assay and con-cTnT assay were evaluated. The serum hs-cTnT levels were detected in apparently healthy subjects to establish reference intervals. Moreover,the long-term and short-term biological variations for hs-cTnT in healthy volunteers were assessed. Results The functional sensitivity of hs-cTnT was 0. 005 μg/L. The within- and between-run precision for lower level control(0. 014 μg/L) and higher level control(2. 500 μg/L) was 2. 97% vs 3. 64%and 0. 66% vs 1.01% ,respectively. The correlation between hs-cTnT assay and con-cTnT assay was good ( R2 =0. 972 ,P <0. 01 ). The 99th percentile in apparently healthy subjects was 0. 003 μg/L for women less than60 years, 0.008 μg/L for men less than 60 years, 0.015 μg/L for women above 60 years and 0. 021 μg/L for men above 60 years. The CVa, CVi, CVg and CVt of short-term biological variations in detecting hs-cTnT from 22 apparently healthy subjects were 3.8%, 4. 8%, 49.9% and 58.5%,respectively. The CVa,CVi ,CVg and CVt of long-term biological variations were 5. 3% ,6. 4% ,56. 6% and 68. 3% respectively. Conclusions The analytical performance of the hs-cTnT is better than con-cTnT assay,achieving acceptable level according to guideline. Our experimental result could provide the basis for the new high sensitivity cTnT assay in the diagnosis of acute myocardial infarction.%目的 评价hs-cTnT的分析性能,了解其生物学变异,建立本实验室参考范围.方法 收集AMI患者100例及表面健康人474名的血清,评价hs-cTnT检测的功能灵敏度和批内、批间不精密度(以CV表示),并与目前使用的con-cTnT进行比较,

  3. Intracavity optogalvanic spectroscopy. An analytical technique for 14C analysis with subattomole sensitivity.

    Science.gov (United States)

    Murnick, Daniel E; Dogru, Ozgur; Ilkmen, Erhan

    2008-07-01

    We show a new ultrasensitive laser-based analytical technique, intracavity optogalvanic spectroscopy, allowing extremely high sensitivity for detection of (14)C-labeled carbon dioxide. Capable of replacing large accelerator mass spectrometers, the technique quantifies attomoles of (14)C in submicrogram samples. Based on the specificity of narrow laser resonances coupled with the sensitivity provided by standing waves in an optical cavity and detection via impedance variations, limits of detection near 10(-15) (14)C/(12)C ratios are obtained. Using a 15-W (14)CO2 laser, a linear calibration with samples from 10(-15) to >1.5 x 10(-12) in (14)C/(12)C ratios, as determined by accelerator mass spectrometry, is demonstrated. Possible applications include microdosing studies in drug development, individualized subtherapeutic tests of drug metabolism, carbon dating and real time monitoring of atmospheric radiocarbon. The method can also be applied to detection of other trace entities.

  4. A Bayesian Multi-Level Factor Analytic Model of Consumer Price Sensitivities across Categories

    Science.gov (United States)

    Duvvuri, Sri Devi; Gruca, Thomas S.

    2010-01-01

    Identifying price sensitive consumers is an important problem in marketing. We develop a Bayesian multi-level factor analytic model of the covariation among household-level price sensitivities across product categories that are substitutes. Based on a multivariate probit model of category incidence, this framework also allows the researcher to…

  5. The efficacy of cognitive-behavioral interventions for reducing anxiety sensitivity: A meta-analytic review

    NARCIS (Netherlands)

    Smits, J.A.J.; Berry, A.C.; Tart, C.D.; Powers, M.B.

    2008-01-01

    The present study meta-analytically reviewed the efficacy of cognitive-behavioral therapy (CBT) vs. control conditions in the reduction of anxiety sensitivity. A computerized search was conducted to indentify CBT outcome studies that included the Anxiety Sensitivity Index as a dependent variable. Of

  6. A Bayesian Multi-Level Factor Analytic Model of Consumer Price Sensitivities across Categories

    Science.gov (United States)

    Duvvuri, Sri Devi; Gruca, Thomas S.

    2010-01-01

    Identifying price sensitive consumers is an important problem in marketing. We develop a Bayesian multi-level factor analytic model of the covariation among household-level price sensitivities across product categories that are substitutes. Based on a multivariate probit model of category incidence, this framework also allows the researcher to…

  7. Mass-Sensitive Biosensor Systems to Determine the Membrane Interaction of Analytes.

    Science.gov (United States)

    Hoß, Sebastian G; Bendas, Gerd

    2017-01-01

    Biosensors are devices that transform a biological interaction into a readout signal, which is evaluable for analytical purposes. The general strength of biosensor approaches is the avoidance of time-consuming and cost-intensive labeling procedures of the analytes. In this chapter, we give insight into a mass-sensitive surface-acoustic wave (SAW) biosensor, which represents an elegant and highly sensitive method to investigate binding events at a molecular level. The principle of SAW technology is based on the piezoelectric properties of the sensors, so as to binding events and their accompanied mass increase at the sensor surface are detectable by a change in the oscillation of the surface acoustic wave. In combination with model membranes, transferred to the sensor surface, the analytical value of SAW biosensors has strongly been increased and extended to different topics of biomedical investigations, including antibiotic research. The interaction with the bacterial membrane or certain target structures therein is the essential mode of action for various antibacterial compounds. Beside targeted interaction, an unspecific membrane binding or membrane insertion of drugs can contribute to the antibacterial activity by changing the lateral order of membrane constituents or by interfering with the membrane barrier function. Those pleiotropic effects are hardly to illustrate in the bacterial systems and need a detailed view at the in vitro level. Here, we illustrate the usefulness of a SAW biosensor in combination with model membranes to investigate the mode of membrane interaction of antibiotic active peptides. Using two different peptides we exemplary describe the interaction analysis in a two-step gain of information: (1) a binding intensity or affinity by analyzing the phase changes of oscillation, and (2) mode of membrane interaction, i.e., surface binding or internalization of the peptide by following the amplitude of oscillation.

  8. Analytic Models of High-Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Stygar, W.A.; Olson, R.E.; Spielman, R.B.; Leeper, R.J.

    2000-11-29

    A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P{sub s} = [A{sub s}+(1{minus}{alpha}{sub W})A{sub W}+A{sub H}]{sigma}T{sub R}{sup 4} + (4V{sigma}/c)(dT{sub R}{sup r}/dt) where P{sub S} is the total power radiated by the source, A{sub s} is the source area, A{sub W} is the area of the cavity wall excluding the source and holes in the wall, A{sub H} is the area of the holes, {sigma} is the Stefan-Boltzmann constant, T{sub R} is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo {alpha}{sub W} {triple_bond} (T{sub W}/T{sub R}){sup 4} where T{sub W} is the brightness temperature of area A{sub W}. The net power radiated by the source P{sub N} = P{sub S}-A{sub S}{sigma}T{sub R}{sup 4}, which suggests that for laser-driven hohlraums the conversion efficiency {eta}{sub CE} be defined as P{sub N}/P{sub LASER}. The characteristic time required to change T{sub R}{sup 4} in response to a change in P{sub N} is 4V/C[(l{minus}{alpha}{sub W})A{sub W}+A{sub H}]. Using this model, T{sub R}, {alpha}{sub W}, and {eta}{sub CE} can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, P{sub N} = {l_brace}(1{minus}{alpha}{sub W})A{sub W}+A{sub H}+[(1{minus}{alpha}{sub C})(A{sub S}+A{sub W}{alpha}{sub W})A{sub C}/A{sub T}]{r_brace}{sigma}T{sub RC}{sup 4} where {alpha}{sub C} is the capsule albedo, A{sub C} is the capsule area, A{sub T} {triple_bond} (A{sub S}+A{sub W}+A{sub H}), and T{sub RC} is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented.

  9. An analytical sensitivity method for use in integrated aeroservoelastic aircraft design

    Science.gov (United States)

    Gilbert, Michael G.

    1989-01-01

    Interdisciplinary analysis capabilities have been developed for aeroservoelastic aircraft and large flexible spacecraft, but the requisite integrated design methods are only beginning to be developed. One integrated design method which has received attention is based on hierarchal problem decompositions, optimization, and design sensitivity analyses. This paper highlights a design sensitivity analysis method for Linear Quadratic Gaussian (LQG) optimal control laws, enabling the use of LQG techniques in the hierarchal design methodology. The LQG sensitivity analysis method calculates the change in the optimal control law and resulting controlled system responses due to changes in fixed design integration parameters using analytical sensitivity equations. Numerical results of a LQG design sensitivity analysis for a realistic aeroservoelastic aircraft example are presented. In this example, the sensitivity of the optimal control law and aircraft response for various parameters such as wing bending natural frequency is determined. The sensitivity results computed from the analytical expressions are used to estimate changes in response resulting from changes in the parameters. Comparisons of the estimates with exact calculated responses show they are reasonably accurate for + or - 15 percent changes in the parameters. Evaluation of the analytical expressions is computationally faster than equivalent finite difference calculations.

  10. High sensitivity RNA pseudoknot prediction

    OpenAIRE

    Huang, Xiaolu; Ali, Hesham

    2006-01-01

    Most ab initio pseudoknot predicting methods provide very few folding scenarios for a given RNA sequence and have low sensitivities. RNA researchers, in many cases, would rather sacrifice the specificity for a much higher sensitivity for pseudoknot detection. In this study, we introduce the Pseudoknot Local Motif Model and Dynamic Partner Sequence Stacking (PLMM_DPSS) algorithm which predicts all PLM model pseudoknots within an RNA sequence in a neighboring-region-interference-free fashion. T...

  11. High sensitivity RNA pseudoknot prediction.

    Science.gov (United States)

    Huang, Xiaolu; Ali, Hesham

    2007-01-01

    Most ab initio pseudoknot predicting methods provide very few folding scenarios for a given RNA sequence and have low sensitivities. RNA researchers, in many cases, would rather sacrifice the specificity for a much higher sensitivity for pseudoknot detection. In this study, we introduce the Pseudoknot Local Motif Model and Dynamic Partner Sequence Stacking (PLMM_DPSS) algorithm which predicts all PLM model pseudoknots within an RNA sequence in a neighboring-region-interference-free fashion. The PLM model is derived from the existing Pseudobase entries. The innovative DPSS approach calculates the optimally lowest stacking energy between two partner sequences. Combined with the Mfold, PLMM_DPSS can also be used in predicting complicated pseudoknots. The test results of PLMM_DPSS, PKNOTS, iterated loop matching, pknotsRG and HotKnots with Pseudobase sequences have shown that PLMM_DPSS is the most sensitive among the five methods. PLMM_DPSS also provides manageable pseudoknot folding scenarios for further structure determination.

  12. High sensitivity radon emanation measurements.

    Science.gov (United States)

    Zuzel, G; Simgen, H

    2009-05-01

    The presented radon detection technique employs miniaturized ultra-low background proportional counters. (222)Rn samples are purified, mixed with a counting gas and filled into a counter using a special glass vacuum line. The absolute sensitivity of the system is estimated to be 40 microBq (20 (222)Rn atoms). For emanation investigations two metal sealed stainless steel vessels and several glass vials are available. Taking into account their blank contributions, measurements at a minimum detectable activity of about 100 microBq can be performed.

  13. Cryogenic High-Sensitivity Magnetometer

    Science.gov (United States)

    Day, Peter; Chui, Talso; Goodstein, David

    2005-01-01

    A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10(exp -16) Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10(exp -10) Tesla). One version of this device, for operation near the low end of the cryogenic temperature range, would include a piece of a paramagnetic material on a platform, the temperature of which would be controlled with a periodic variation. The variation in temperature would be measured by use of a conventional germanium resistance thermometer. A superconducting coil would be wound around the paramagnetic material and coupled to a superconducting quantum interference device (SQUID) magnetometer.

  14. Analytical and Experimental Investigation on A Dynamic Thermo-Sensitive Electrical Parameter with Maximum dIC/dt during Turn-off for High Power Trench Gate/Field-Stop IGBT Modules

    DEFF Research Database (Denmark)

    Chen, Yuxiang; Luo, Haoze; Li, Wuhua

    2017-01-01

    In this paper, a dynamic thermo-sensitive electrical parameter (DTSEP) for extracting the junction temperature of the trench gate/field-stop insulated gate bipolar transistor (IGBT) modules by using the maximum collector current falling rate is proposed. First, a theoretical model of the transient...

  15. Structural Glycomic Analyses at High Sensitivity: A Decade of Progress

    Science.gov (United States)

    Alley, William R.; Novotny, Milos V.

    2013-06-01

    The field of glycomics has recently advanced in response to the urgent need for structural characterization and quantification of complex carbohydrates in biologically and medically important applications. The recent success of analytical glycobiology at high sensitivity reflects numerous advances in biomolecular mass spectrometry and its instrumentation, capillary and microchip separation techniques, and microchemical manipulations of carbohydrate reactivity. The multimethodological approach appears to be necessary to gain an in-depth understanding of very complex glycomes in different biological systems.

  16. Nano-textured high sensitivity ion sensitive field effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Hajmirzaheydarali, M.; Sadeghipari, M.; Akbari, M.; Shahsafi, A.; Mohajerzadeh, S., E-mail: mohajer@ut.ac.ir [Thin Film and Nanoelectronics Lab, Nanoelectronics Center of Excellence, School of Electrical and Computer Engineering, University of Tehran, Tehran 143957131 (Iran, Islamic Republic of)

    2016-02-07

    Nano-textured gate engineered ion sensitive field effect transistors (ISFETs), suitable for high sensitivity pH sensors, have been realized. Utilizing a mask-less deep reactive ion etching results in ultra-fine poly-Si features on the gate of ISFET devices where spacing of the order of 10 nm and less is achieved. Incorporation of these nano-sized features on the gate is responsible for high sensitivities up to 400 mV/pH in contrast to conventional planar structures. The fabrication process for this transistor is inexpensive, and it is fully compatible with standard complementary metal oxide semiconductor fabrication procedure. A theoretical modeling has also been presented to predict the extension of the diffuse layer into the electrolyte solution for highly featured structures and to correlate this extension with the high sensitivity of the device. The observed ultra-fine features by means of scanning electron microscopy and transmission electron microscopy tools corroborate the theoretical prediction.

  17. Recent analytical applications of nanoparticle sensitized lucigenin and luminol chemiluminescent reactions

    Indian Academy of Sciences (India)

    S M Wabaidur; Mu Naushad; Z A Alothman

    2012-02-01

    There is an ever-increasing demand for rapid, sensitive, cost effective and selective detection methods for the analysis of many essential compounds.When chemiluminescence has been introduced to analytical chemistry as a detection technique, it has been shown to meet many of these requirements. This method has become a powerful tool for the determination of many compounds. Using this method, low detection limits can be obtained with simple and inexpensive instrumentation. Coupled with flow injection technique the method has become more popular for wider applications. Since many excellent reviews on the chemiluminogenic techniques have appeared in the literature in recent years, the present paper does not intend to cover the exhaustive studies in this area, but will selectively describe the analytical applications of nanoparticle sensitized lucigenin and luminol chemiluminescent reactions and evaluate their recent progress together with our present work.

  18. Toward Analytic Solution of Nonlinear Differential Difference Equations via Extended Sensitivity Approach

    Institute of Scientific and Technical Information of China (English)

    G. Darmani; S. Setayeshi; H. Ramezanpour

    2012-01-01

    In this paper an efficient computational method based on extending the sensitivity approach (SA) is proposed to find an analytic exact solution of nonlinear differential difference equations. In this manner we avoid solving the nonlinear problem directly. By extension of sensitivity approach for differential difference equations (DDEs), the nonlinear original problem is transformed into infinite linear differential difference equations, which should be solved in a recursive manner. Then the exact solution is determined in the form of infinite terms series and by intercepting series an approximate solution is obtained. Numerical examples are employed to show the effectiveness of the proposed approach.

  19. Analytical sensitivities and energies of thermal-neutron-capture gamma rays

    Science.gov (United States)

    Duffey, D.; El-Kady, A.; Senftle, F.E.

    1970-01-01

    A table of the analytical sensitivities of the principal lines in the thermal-neutron-capture gamma ray spectrum has been compiled for most of the elements. In addition a second table of the full-energy, single-escape, and double-escape peaks has been compiled according to energy for all significant lines above 3 MeV. Lines that contrast well with adjacent lines are noted as prominent. The tables are useful for spectral interpretation and calibration. ?? 1970.

  20. Analytical sensitivities and energies of thermal neutron capture gamma rays II

    Science.gov (United States)

    Senftle, F.E.; Moore, H.D.; Leep, D.B.; El-Kady, A.; Duffey, D.

    1971-01-01

    A table of the analytical sensitivities of the principal lines in the thermal neutron capture gamma-ray spectrum from 0 to 3 MeV has been compiled for most of the elements. A tabulation of the full-energy, single-escape, and double-escape peaks has also been made according to energy. The tables are useful for spectral interpretation and calibration. ?? 1971.

  1. Function-weighted frequency response function sensitivity method for analytical model updating

    Science.gov (United States)

    Lin, R. M.

    2017-09-01

    Since the frequency response function (FRF) sensitivity method was first proposed [26], it has since become a most powerful and practical method for analytical model updating. Nevertheless, the original formulation of the FRF sensitivity method does suffer the limitation that the initial analytical model to be updated should be reasonably close to the final updated model to be sought, due the assumed mathematical first order approximation implicit to most sensitivity based methods. Convergence to correct model is not guaranteed when large modelling errors exist and blind application often leads to optimal solutions which are truly sought. This paper seeks to examine all the important numerical characteristics of the original FRF sensitivity method including frequency data selection, numerical balance and convergence performance. To further improve the applicability of the method to cases of large modelling errors, a new novel function-weighted sensitivity method is developed. The new method has shown much superior performance on convergence even in the presence of large modelling errors. Extensive numerical case studies based on a mass-spring system and a GARTEUR structure have been conducted and very encouraging results have been achieved. Effect of measurement noise has been examined and the method works reasonably well in the presence of measurement uncertainties. The new method removes the restriction of modelling error magnitude being of second order in Euclidean norm as compared with that of system matrices, thereby making it a truly general method applicable to most practical model updating problems.

  2. Analytical sensitivity of four commonly used hCG point of care devices.

    Science.gov (United States)

    Kamer, Sandy M; Foley, Kevin F; Schmidt, Robert L; Greene, Dina N

    2015-04-01

    Point of care (POC) hCG assays are often used to rule-out pregnancy and therefore diagnostic sensitivity, especially at low concentrations of hCG, is important. There are very few studies in the literature that seek to verify the claimed analytical sensitivity of hCG POC devices. The analytical sensitivity of four commonly used hCG POC devices (Alere hCG Combo Cassette, ICON 20 hCG, OSOM hCG Combo Test, and Sure-Vue Serum/Urine hCG-STAT) was challenged using urine samples (n=50) selected based on quantitative hCG concentrations. The majority of these specimens (n=40) had an hCG concentration between 20 and 200 U/L. Each specimen/device combination was reviewed by three individuals. Statistical calculations were performed using Stata 12. The analytical sensitivity of the OSOM was significantly lower inferior than that of the other POC devices. There was no significant difference in the sensitivity of the Alere, ICON 20 and Sure-Vue devices. There was no significant difference in the individual interpretation of the hCG POC results. All hCG POC devices evaluated in this study were susceptible to false negative results at low concentrations of urine hCG. Laboratorians and clinicians should be aware that there are limitations when using urine hCG POC devices to rule out early pregnancy. Copyright © 2014 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.

  3. Associations between rejection sensitivity and mental health outcomes: A meta-analytic review.

    Science.gov (United States)

    Gao, Shuling; Assink, Mark; Cipriani, Andrea; Lin, Kangguang

    2017-08-15

    Rejection sensitivity is a personality disposition characterized by oversensitivity to social rejection. Using a three-level meta-analytic model, 75 studies were reviewed that examined associations between rejection sensitivity and five mental health outcomes: depression, anxiety, loneliness, borderline personality disorder, and body dysmorphic disorder. The results showed significant and moderate associations between rejection sensitivity and depression (pooled r=0.332; p<0.001), anxiety (pooled r=0.407; p<0.001), loneliness (pooled r=0.386; p<0.001), borderline personality disorder (pooled r=0.413; p<0.001), and body dysmorphic disorder (pooled r=0.428; p<0.001). The associations between rejection sensitivity and depression, anxiety, and borderline personality disorder varied by type of sample, but the associations were similar for clinical and non-clinical (i.e., community) samples. The association between rejection sensitivity and anxiety was negatively moderated by percentage of females in samples. The association between rejection sensitivity and depression was negatively moderated by length of follow-up. The longitudinal associations between rejection sensitivity and depression, anxiety, and loneliness were stable over time. Implications of the findings for both risk assessment and prevention and intervention strategies in mental health practice are discussed. Copyright © 2017. Published by Elsevier Ltd.

  4. Analytical Model for High Impedance Fault Analysis in Transmission Lines

    Directory of Open Access Journals (Sweden)

    S. Maximov

    2014-01-01

    Full Text Available A high impedance fault (HIF normally occurs when an overhead power line physically breaks and falls to the ground. Such faults are difficult to detect because they often draw small currents which cannot be detected by conventional overcurrent protection. Furthermore, an electric arc accompanies HIFs, resulting in fire hazard, damage to electrical devices, and risk with human life. This paper presents an analytical model to analyze the interaction between the electric arc associated to HIFs and a transmission line. A joint analytical solution to the wave equation for a transmission line and a nonlinear equation for the arc model is presented. The analytical model is validated by means of comparisons between measured and calculated results. Several cases of study are presented which support the foundation and accuracy of the proposed model.

  5. High sensitivity knitted fabric strain sensors

    Science.gov (United States)

    Xie, Juan; Long, Hairu; Miao, Menghe

    2016-10-01

    Wearable sensors are increasingly used in smart garments for detecting and transferring vital signals and body posture, movement and respiration. Existing fabric strain sensors made from metallized yarns have low sensitivity, poor comfort and low durability to washing. Here we report a knitted fabric strain sensor made from a cotton/stainless steel (SS) fibre blended yarn which shows much higher sensitivity than sensors knitted from metallized yarns. The fabric feels softer than pure cotton textiles owing to the ultrafine stainless steel fibres and does not lose its electrical property after washing. The reason for the high sensitivity of the cotton/SS knitted fabric sensor was explored by comparing its sensing mechanism with the knitted fabric sensor made from metallized yarns. The results show that the cotton/SS yarn-to-yarn contact resistance is highly sensitive to strain applied to hooked yarn loops.

  6. Mineral saturation states in natural waters and their sensitivity to thermodynamic and analytic errors

    Science.gov (United States)

    Nordstrom, D.K.; Ball, J.W.

    1989-01-01

    Saturation indices computed with WATEQ4F for chemical analyses from a groundwater in crystalline bedrock and a surface water receiving acid mine drainage are frequently at or above saturation with respect to calcite, fluorite, barite, gibbsite and ferrihydrite. A sensitivity analysis has been performed by varying the analytic and thermodynamic parameters for which the saturation indices are most sensitive. For calcite, fluorite and barite, the supersaturation effect appears to be real because it is only slightly decreased by sources of uncertainty. Apparent supersaturation for gibbsite is most likely caused by the degree of crystallinity on solubility behavior. Apparent supersaturation for ferric hydroxide is likely caused by small colloidal particles (<0.1 ??m) in the water sample that cannot be removed by standard field filtration, although several other possible explanations cannot be easily excluded. -from Authors

  7. High Sensitivity deflection detection of nanowires

    Energy Technology Data Exchange (ETDEWEB)

    Sanii, Babak; Ashby, Paul

    2009-10-28

    A critical limitation of nanoelectromechanical systems (NEMS) is the lack of a high-sensitivity position detection mechanism. We introduce a noninterferometric optical approach to determine the position of nanowires with a high sensitivity and bandwidth. Its physical origins and limitations are determined by Mie scattering analysis. This enables a dramatic miniaturization of detectable cantilevers, with attendant reductions to the fundamental minimum force noise in highly damping environments. We measure the force noise of an 81{+-}9??nm radius Ag{sub 2}Ga nanowire cantilever in water at 6{+-}3??fN/{radical}Hz.

  8. Covalent functionalization of single-walled carbon nanotubes with polytyrosine: Characterization and analytical applications for the sensitive quantification of polyphenols.

    Science.gov (United States)

    Eguílaz, Marcos; Gutiérrez, Alejandro; Gutierrez, Fabiana; González-Domínguez, Jose Miguel; Ansón-Casaos, Alejandro; Hernández-Ferrer, Javier; Ferreyra, Nancy F; Martínez, María T; Rivas, Gustavo

    2016-02-25

    This work reports the synthesis and characterization of single-walled carbon nanotubes (SWCNT) covalently functionalized with polytyrosine (Polytyr); the critical analysis of the experimental conditions to obtain the efficient dispersion of the modified carbon nanotubes; and the analytical performance of glassy carbon electrodes (GCE) modified with the dispersion (GCE/SWCNT-Polytyr) for the highly sensitive quantification of polyphenols. Under the optimal conditions, the calibration plot for the amperometric response of gallic acid (GA) shows a linear range between 5.0 × 10(-7) and 1.7 × 10(-4) M, with a sensitivity of (518 ± 5) m AM(-1) cm(-2), and a detection limit of 8.8 nM. The proposed sensor was successfully used for the determination of total polyphenolic content in tea extracts.

  9. Linear Analytical Solutions of Mechanical Sensitivity in Large Deflection of Unsymmetrically Layered Piezoelectric Plate under Pretension

    Directory of Open Access Journals (Sweden)

    Chun-Fu Chen

    2014-03-01

    Full Text Available Linear analytical study on the mechanical sensitivity in large deflection of unsymmetrically layered and laterally loaded piezoelectric plate under pretension is conducted. von Karman plate theory for large deflection is utilized but extended to the case of an unsymmetrically layered plate embedded with a piezoelectric layer. The governing equations thus obtained are simplified by omitting the arising nonlinear terms, yielding a Bessel or modified Bessel equation for the lateral slope. Depending on the relative magnitude of the piezoelectric effect, for both cases, analytical solutions of various geometrical responses are developed and formulated via Bessel and modified Bessel functions. The associated ultimate radial stresses are further derived following lamina constitutive law to evaluate the mechanical sensitivity of the considered plate. For a nearly monolithic plate under a very low applied voltage, the results are in good agreement with those for a single-layered case due to pure mechanical load available in literature, and thus the present approach is checked. For a two-layered unsymmetric plate made of typical silicon-based materials, a sound piezoelectric effect is illustrated particularly in a low pretension condition.

  10. Sensitivity of the NMR density matrix to pulse sequence parameters: a simplified analytic approach.

    Science.gov (United States)

    Momot, Konstantin I; Takegoshi, K

    2012-08-01

    We present a formalism for the analysis of sensitivity of nuclear magnetic resonance pulse sequences to variations of pulse sequence parameters, such as radiofrequency pulses, gradient pulses or evolution delays. The formalism enables the calculation of compact, analytic expressions for the derivatives of the density matrix and the observed signal with respect to the parameters varied. The analysis is based on two constructs computed in the course of modified density-matrix simulations: the error interrogation operators and error commutators. The approach presented is consequently named the Error Commutator Formalism (ECF). It is used to evaluate the sensitivity of the density matrix to parameter variation based on the simulations carried out for the ideal parameters, obviating the need for finite-difference calculations of signal errors. The ECF analysis therefore carries a computational cost comparable to a single density-matrix or product-operator simulation. Its application is illustrated using a number of examples from basic NMR spectroscopy. We show that the strength of the ECF is its ability to provide analytic insights into the propagation of errors through pulse sequences and the behaviour of signal errors under phase cycling. Furthermore, the approach is algorithmic and easily amenable to implementation in the form of a programming code. It is envisaged that it could be incorporated into standard NMR product-operator simulation packages.

  11. ICL-Based OF-CEAS: A Sensitive Tool for Analytical Chemistry.

    Science.gov (United States)

    Manfred, Katherine M; Hunter, Katharine M; Ciaffoni, Luca; Ritchie, Grant A D

    2017-01-03

    Optical-feedback cavity-enhanced absorption spectroscopy (OF-CEAS) using mid-infrared interband cascade lasers (ICLs) is a sensitive technique for trace gas sensing. The setup of a V-shaped optical cavity operating with a 3.29 μm cw ICL is detailed, and a quantitative characterization of the injection efficiency, locking stability, mode matching, and detection sensitivity is presented. The experimental data are supported by a model to show how optical feedback affects the laser frequency as it is scanned across several longitudinal modes of the optical cavity. The model predicts that feedback enhancement effects under strongly absorbing conditions can cause underestimations in the measured absorption, and these predictions are verified experimentally. The technique is then used in application to the detection of nitrous oxide as an exemplar of the utility of this technique for analytical gas phase spectroscopy. The analytical performance of the spectrometer, expressed as noise equivalent absorption coefficient, was estimated as 4.9 × 10(-9) cm (-1) Hz(-1/2), which compares well with recently reported values.

  12. High sensitivity optically pumped quantum magnetometer.

    Science.gov (United States)

    Tiporlini, Valentina; Alameh, Kamal

    2013-01-01

    Quantum magnetometers based on optical pumping can achieve sensitivity as high as what SQUID-based devices can attain. In this paper, we discuss the principle of operation and the optimal design of an optically pumped quantum magnetometer. The ultimate intrinsic sensitivity is calculated showing that optimal performance of the magnetometer is attained with an optical pump power of 20 μW and an operation temperature of 48°C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327 fT/Hz(½) over a bandwidth of 26 Hz and that this sensitivity drops to 130 pT/Hz(½) in the presence of environmental noise. The quantum magnetometer is shown to be capable of detecting a sinusoidal magnetic field of amplitude as low as 15 pT oscillating at 25 Hz.

  13. Aluminum nanocantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nanocantilevers using a simple, one mask contact UV lithography technique with lateral and vertical dimensions under 500 and 100 nm, respectively. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Furthermore, it is shown ...

  14. Nonclassical characteristic functions for highly sensitive measurements

    CERN Document Server

    Richter, T; Richter, Th.

    2007-01-01

    Characteristic functions are shown to be useful for highly sensitive measurements. Redistributions of motional Fock states of a trapped atom can be directly monitored via the most fragile nonclassical part of the characteristic function. The method can also be used for decoherence measurements in optical quantum-information systems.

  15. Analytical expression for position sensitivity of linear response beam position monitor having inter-electrode cross talk

    Science.gov (United States)

    Kumar, Mukesh; Ojha, A.; Garg, A. D.; Puntambekar, T. A.; Senecha, V. K.

    2017-02-01

    According to the quasi electrostatic model of linear response capacitive beam position monitor (BPM), the position sensitivity of the device depends only on the aperture of the device and it is independent of processing frequency and load impedance. In practice, however, due to the inter-electrode capacitive coupling (cross talk), the actual position sensitivity of the device decreases with increasing frequency and load impedance. We have taken into account the inter-electrode capacitance to derive and propose a new analytical expression for the position sensitivity as a function of frequency and load impedance. The sensitivity of a linear response shoe-box type BPM has been obtained through simulation using CST Studio Suite to verify and confirm the validity of the new analytical equation. Good agreement between the simulation results and the new analytical expression suggest that this method can be exploited for proper designing of BPM.

  16. High blood pressure and visual sensitivity

    Science.gov (United States)

    Eisner, Alvin; Samples, John R.

    2003-09-01

    The study had two main purposes: (1) to determine whether the foveal visual sensitivities of people treated for high blood pressure (vascular hypertension) differ from the sensitivities of people who have not been diagnosed with high blood pressure and (2) to understand how visual adaptation is related to standard measures of systemic cardiovascular function. Two groups of middle-aged subjects-hypertensive and normotensive-were examined with a series of test/background stimulus combinations. All subjects met rigorous inclusion criteria for excellent ocular health. Although the visual sensitivities of the two subject groups overlapped extensively, the age-related rate of sensitivity loss was, for some measures, greater for the hypertensive subjects, possibly because of adaptation differences between the two groups. Overall, the degree of steady-state sensitivity loss resulting from an increase of background illuminance (for 580-nm backgrounds) was slightly less for the hypertensive subjects. Among normotensive subjects, the ability of a bright (3.8-log-td), long-wavelength (640-nm) adapting background to selectively suppress the flicker response of long-wavelength-sensitive (LWS) cones was related inversely to the ratio of mean arterial blood pressure to heart rate. The degree of selective suppression was also related to heart rate alone, and there was evidence that short-term changes of cardiovascular response were important. The results suggest that (1) vascular hypertension, or possibly its treatment, subtly affects visual function even in the absence of eye disease and (2) changes in blood flow affect retinal light-adaptation processes involved in the selective suppression of the flicker response from LWS cones caused by bright, long-wavelength backgrounds.

  17. Highly Energetic, Low Sensitivity Aromatic Peroxy Acids.

    Science.gov (United States)

    Gamage, Nipuni-Dhanesha H; Stiasny, Benedikt; Stierstorfer, Jörg; Martin, Philip D; Klapötke, Thomas M; Winter, Charles H

    2016-02-18

    The synthesis, structure, and energetic materials properties of a series of aromatic peroxy acid compounds are described. Benzene-1,3,5-tris(carboperoxoic) acid is a highly sensitive primary energetic material, with impact and friction sensitivities similar to those of triacetone triperoxide. By contrast, benzene-1,4-bis(carboperoxoic) acid, 4-nitrobenzoperoxoic acid, and 3,5-dinitrobenzoperoxoic acid are much less sensitive, with impact and friction sensitivities close to those of the secondary energetic material 2,4,6-trinitrotoluene. Additionally, the calculated detonation velocities of 3,5-dinitrobenzoperoxoic acid and 2,4,6-trinitrobenzoperoxoic acid exceed that of 2,4,6-trinitrotoluene. The solid-state structure of 3,5-dinitrobenzoperoxoic acid contains intermolecular O-H⋅⋅⋅O hydrogen bonds and numerous N⋅⋅⋅O, C⋅⋅⋅O, and O⋅⋅⋅O close contacts. These attractive lattice interactions may account for the less sensitive nature of 3,5-dinitrobenzoperoxoic acid.

  18. Design of highly sensitive multichannel bimetallic photonic crystal fiber biosensor

    Science.gov (United States)

    Hameed, Mohamed Farhat O.; Alrayk, Yassmin K. A.; Shaalan, Abdelhamid A.; El Deeb, Walid S.; Obayya, Salah S. A.

    2016-10-01

    A design of a highly sensitive multichannel biosensor based on photonic crystal fiber is proposed and analyzed. The suggested design has a silver layer as a plasmonic material coated by a gold layer to protect silver oxidation. The reported sensor is based on detection using the quasi transverse electric (TE) and quasi transverse magnetic (TM) modes, which offers the possibility of multichannel/multianalyte sensing. The numerical results are obtained using a finite element method with perfect matched layer boundary conditions. The sensor geometrical parameters are optimized to achieve high sensitivity for the two polarized modes. High-refractive index sensitivity of about 4750 nm/RIU (refractive index unit) and 4300 nm/RIU with corresponding resolutions of 2.1×10-5 RIU, and 2.33×10-5 RIU can be obtained according to the quasi TM and quasi TE modes of the proposed sensor, respectively. Further, the reported design can be used as a self-calibration biosensor within an unknown analyte refractive index ranging from 1.33 to 1.35 with high linearity and high accuracy. Moreover, the suggested biosensor has advantages in terms of compactness and better integration of microfluidics setup, waveguide, and metallic layers into a single structure.

  19. Theory of high gain harmonic generation an analytical estimate

    CERN Document Server

    Yu Li Hua

    2002-01-01

    We discuss the theory of the High Gain Harmonic Generation (HGHG). First, we describe an analytical estimate using the HGHG parameters in the DUVFEL project at BNL as an example. We show that the effective energy spread in a chicane dispersion section is found to be very small, and the effect of finite emittance can be neglected during the calculation of coherent harmonic generation. Then we discuss some issues such as the intensity stability, and how to use HGHG to obtain information about local energy spread. We compare these issues with recent experimental results in the infrared. We discuss some of the key issues in the cascading HGHG scheme and its possible limitations.

  20. Polymer Inclusion Membranes with Condensed Phase Membrane Introduction Mass Spectrometry (CP-MIMS): Improved Analytical Response Time and Sensitivity.

    Science.gov (United States)

    Vandergrift, Gregory W; Krogh, Erik T; Gill, Chris G

    2017-05-16

    Condensed phase membrane introduction mass spectrometry (CP-MIMS) is an online, in situ analysis technique for low volatility analytes. Analytes diffuse through a hollow fiber membrane, where they are then dissolved by a liquid (condensed) acceptor phase flowing through the membrane lumen. Permeating analytes are entrained to an atmospheric pressure ionization source for subsequent measurement by a mass spectrometer. Larger analytes, with inherently lower diffusivities, suffer from lengthy response times and lower sensitivity, limiting the use of CP-MIMS for their online, real-time measurement. We present the use of a heptane cosolvent in a methanol acceptor phase in combination with a polydimethylsiloxane (PDMS) membrane. The heptane generates an in situ polymer inclusion membrane (PIM) with the PDMS. We report improved measurement response times and greater sensitivity across a suite of analytes studied (gemfibrozil, nonylphenol, triclosan, 2,4,6-trichlorophenol, and naphthenic acids), with detection limits in the low parts per trillion (ppt) range. These improvements are attributed to increasing analyte diffusivities, as well as increased analyte partitioning across the PIM. Response times are ∼3× faster for the larger analytes studied, and calibration sensitivity is improved by up to ∼3.5× using 0.046 mole fraction heptane in the methanol acceptor. We report the use of short sample exposure times and the use of non-steady-state signals to reduce the analytical duty cycle, and illustrate that the use of a PIM provides a simple and robust variant of CP-MIMS amenable to rapid screening of analytes in complex samples.

  1. Highly sensitive detection using microring resonator and nanopores

    Science.gov (United States)

    Bougot-Robin, K.; Hoste, J. W.; Le Thomas, N.; Bienstman, P.; Edel, J. B.

    2016-04-01

    One of the most significant challenges facing physical and biological scientists is the accurate detection and identification of single molecules in free-solution environments. The ability to perform such sensitive and selective measurements opens new avenues for a large number of applications in biological, medical and chemical analysis, where small sample volumes and low analyte concentrations are the norm. Access to information at the single or few molecules scale is rendered possible by a fine combination of recent advances in technologies. We propose a novel detection method that combines highly sensitive label-free resonant sensing obtained with high-Q microcavities and position control in nanoscale pores (nanopores). In addition to be label-free and highly sensitive, our technique is immobilization free and does not rely on surface biochemistry to bind probes on a chip. This is a significant advantage, both in term of biology uncertainties and fewer biological preparation steps. Through combination of high-Q photonic structures with translocation through nanopore at the end of a pipette, or through a solid-state membrane, we believe significant advances can be achieved in the field of biosensing. Silicon microrings are highly advantageous in term of sensitivity, multiplexing, and microfabrication and are chosen for this study. In term of nanopores, we both consider nanopore at the end of a nanopipette, with the pore being approach from the pipette with nanoprecise mechanical control. Alternatively, solid state nanopores can be fabricated through a membrane, supporting the ring. Both configuration are discussed in this paper, in term of implementation and sensitivity.

  2. Highly sensitive catalytic spectrophotometric determination of ruthenium

    Science.gov (United States)

    Naik, Radhey M.; Srivastava, Abhishek; Prasad, Surendra

    2008-01-01

    A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of L-phenylalanine ( L-Pheala) by KMnO 4 in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526 nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (Δ At) versus added Ru(III) amounts in the range of 0.101-2.526 ng ml -1 is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5 min is 0.08 ng ml -1, and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison.

  3. Transitioning high sensitivity cardiac troponin I (hs-cTnI) into routine diagnostic use: More than just a sensitivity issue

    LENUS (Irish Health Repository)

    Lee, Graham R

    2016-04-01

    High sensitivity cardiac troponin T and I (hs-cTnT and hs-cTnI) assays show analytical, diagnostic and prognostic improvement over contemporary sensitive cTn assays. However, given the importance of troponin in the diagnosis of myocardial infarction, implementing this test requires rigorous analytical and clinical verification across the total testing pathway. This was the aim of this study.

  4. Developing on-demand secure high-performance computing services for biomedical data analytics.

    Science.gov (United States)

    Robison, Nicholas; Anderson, Nick

    2013-01-01

    We propose a technical and process model to support biomedical researchers requiring on-demand high performance computing on potentially sensitive medical datasets. Our approach describes the use of cost-effective, secure and scalable techniques for processing medical information via protected and encrypted computing clusters within a model High Performance Computing (HPC) environment. The process model supports an investigator defined data analytics platform capable of accepting secure data migration from local clinical research data silos into a dedicated analytic environment, and secure environment cleanup upon completion. We define metrics to support the evaluation of this pilot model through performance and stability tests, and describe evaluation of its suitability towards enabling rapid deployment by individual investigators.

  5. High-sensitive cardiac troponin T

    Institute of Scientific and Technical Information of China (English)

    Ru-Yi Xu; Xiao-Fa Zhu; Ye Yang; Ping Ye

    2013-01-01

    Cardiac troponin is the preferred biomarker for the diagnosis of acute myocardial infarction (AMI). The recent development of a high-sensitive cardiac troponin T (hs-cTnT) assay permits detection of very low levels of cTnT. Using the hs-cTnT assay improves the overall diagnostic accuracy in patients with suspected AMI, while a negative result also has a high negative predictive value. The gain in sensitivity may be particularly important in patients with a short duration from symptom onset to admission. Measurement of cardiac troponin T with the hs-cTnT assay may provide strong prognostic information in patients with acute coronary syndromes, stable coronary artery disease, heart failure and even in the general population; however, increased sensitivity comes at a cost of decreased specificity. Serial testing, as well as clinical context and co-existing diseases, are likely to become increasingly important for the interpretation of hs-cTnT assay results.

  6. A highly sensitive method for quantification of iohexol

    DEFF Research Database (Denmark)

    Schulz, A.; Boeringer, F.; Swifka, J.

    2014-01-01

    lohexol (1-N,3-N-bis(2,3-dihydroxypropyl)-5-IN-(2,3-dihydroxypropyl) acetamide-2,4,6-triiodobenzene1,3-dicarboxamide) is used for accurate determination of the glomerular filtration rate (GFR) in chronic kidney disease (CKD) patients. However, high iohexol amounts might lead to adverse effects in...... in organisms. In order to minimize the iohexol dosage required for the GFR determination in humans, the development of a sensitive quantification method is essential. Therefore, the objective of our preclinical study was to establish and validate a simple and robust liquid...... with a cut-off of 3 kDa. The chromatographic separation was achieved on an analytical Zorbax SB C18 column. The detection and quantification were performed on a high capacity trap mass spectrometer using positive ion ESI in the multiple reaction monitoring (MRM) mode. Furthermore, using real-time polymerase...

  7. School of Analytic Computing in Theoretical High-Energy Physics

    CERN Document Server

    2013-01-01

    In recent years, a huge progress has been made on computing rates for production processes of direct relevance to experiments at the Large Hadron Collider (LHC). Crucial to that remarkable advance has been our understanding and ability to compute scattering amplitudes. The aim of the School is to bring together young theorists working on the phenomenology of LHC physics with those working in more formal areas, and to provide them the analytic tools to compute amplitudes in gauge theories. The school is addressed to Ph.D. students and post-docs in Theoretical High-Energy Physics. 30 hours of lectures will be delivered over the 5 days of the School. A Poster Session will be held, at which students are welcome to present their research topics.

  8. School of Analytic Computing in Theoretical High-Energy Physics

    CERN Document Server

    2015-01-01

    In recent years, a huge progress has been made on computing rates for production processes of direct relevance to experiments at the Large Hadron Collider (LHC). Crucial to that remarkable advance has been our understanding and ability to compute scattering amplitudes and cross sections. The aim of the School is to bring together young theorists working on the phenomenology of LHC physics with those working in more formal areas, and to provide them the analytic tools to compute amplitudes in gauge theories. The school is addressed to Ph.D. students and post-docs in Theoretical High-Energy Physics. 30 hours of lectures and 4 hours of tutorials will be delivered over the 6 days of the School.

  9. High-Performance data flows using analytical models and measurements

    Energy Technology Data Exchange (ETDEWEB)

    Rao, Nageswara S [ORNL; Towlsey, D. [University of Massachusetts; Vardoyan, G. [University of Massachusetts; Kettimuthu, R. [Argonne National Laboratory (ANL); Foster, I. [Argonne National Laboratory (ANL); Settlemyer, Bradley [Los Alamos National Laboratory (LANL)

    2016-01-01

    The combination of analytical models and measurements provide practical configurations and parameters to achieve high data transport rates: (a) buffer sizes and number of parallel streams for improved memory and file transfer rates, (b) Hamilton and Scalable TCP congestion control modules for memory transfers in place of default CUBIC, and (c) direct IO mode for Lustre file systems for wide-area transfers. Conventional parameter selection using full sweeps is impractical in many cases since it takes months. By exploiting the unimodality of throughput profiles, we developed the d-w method that significantly reduces the number of measurements needed for parameter identification. This heuristic method was effective in practice in reducing the measurements by about 90% for Lustre and XFS file transfers.

  10. Analytical approach to high harmonics spectrum in the nanobunching regime

    CERN Document Server

    Cherednychek, Mykyta

    2016-01-01

    With the high-order harmonic generation (HHG) from plasma sur- faces it is possible to turn a laser pulse into a train of attosecond or even zeptosecond pulses in the backward radiation. These attosecond pulses may have amplitude several orders of magnitude higher than that of the laser pulse under appropriate conditions. We study this process in detail, especially the nanobunching of the plasma electron density. We derive an analytical expression that describes the electron density pro- file and obtain a good agreement with particle-in-cell simulation results. We investigate the most efficient case of HHG at moderate laser intensity (I = 2*10^20 W/cm^2 ) on the over-dense plasma slab with an exponential profile pre-plasma. Subsequently we calculate the spectra of a single at- tosecond pulse from the backward radiation using our expression for the density shape in combination with the equation for the spectrum of the nanobunch radiation.

  11. Photodetector having high speed and sensitivity

    Science.gov (United States)

    Morse, Jeffrey D.; Mariella, Jr., Raymond P.

    1991-01-01

    The present invention provides a photodetector having an advantageous combination of sensitivity and speed; it has a high sensitivity while retaining high speed. In a preferred embodiment, visible light is detected, but in some embodiments, x-rays can be detected, and in other embodiments infrared can be detected. The present invention comprises a photodetector having an active layer, and a recombination layer. The active layer has a surface exposed to light to be detected, and comprises a semiconductor, having a bandgap graded so that carriers formed due to interaction of the active layer with the incident radiation tend to be swept away from the exposed surface. The graded semiconductor material in the active layer preferably comprises Al.sub.1-x Ga.sub.x As. An additional sub-layer of graded In.sub.1-y Ga.sub.y As may be included between the Al.sub.1-x Ga.sub.x As layer and the recombination layer. The recombination layer comprises a semiconductor material having a short recombination time such as a defective GaAs layer grown in a low temperature process. The recombination layer is positioned adjacent to the active layer so that carriers from the active layer tend to be swept into the recombination layer. In an embodiment, the photodetector may comprise one or more additional layers stacked below the active and recombination layers. These additional layers may include another active layer and another recombination layer to absorb radiation not absorbed while passing through the first layers. A photodetector having a stacked configuration may have enhanced sensitivity and responsiveness at selected wavelengths such as infrared.

  12. High sensitivity troponin and valvular heart disease.

    Science.gov (United States)

    McCarthy, Cian P; Donnellan, Eoin; Phelan, Dermot; Griffin, Brian P; Sarano, Maurice Enriquez-; McEvoy, John W

    2017-01-16

    Blood-based biomarkers have been extensively studied in a range of cardiovascular diseases and have established utility in routine clinical care, most notably in the diagnosis of acute coronary syndrome (e.g., troponin) and the management of heart failure (e.g., brain-natriuretic peptide). The role of biomarkers is less well established in the management of valvular heart disease (VHD), in which the optimal timing of surgical intervention is often challenging. One promising biomarker that has been the subject of a number of recent VHD research studies is high sensitivity troponin (hs-cTn). Novel high-sensitivity assays can detect subclinical myocardial damage in asymptomatic individuals. Thus, hs-cTn may have utility in the assessment of asymptomatic patients with severe VHD who do not have a clear traditional indication for surgical intervention. In this state-of-the-art review, we examine the current evidence for hs-cTn as a potential biomarker in the most commonly encountered VHD conditions, aortic stenosis and mitral regurgitation. This review provides a synopsis of early evidence indicating that hs-cTn has promise as a biomarker in VHD. However, the impact of its measurement on clinical practice and VHD outcomes needs to be further assessed in prospective studies before routine clinical use becomes a reality.

  13. Ophidia: high performance data analytics for climate change

    Science.gov (United States)

    Fiore, S.; Williams, D. N.; Foster, I.; Aloisio, G.

    2013-12-01

    This work presents the most relevant results related to the Ophidia project, a big data analytics research effort applied to climate change. It combines together high perfomance computing and database management systems to provide users with an efficient and climate-oriented data analytics platform. Ophidia extends, in terms of both Structured Query Language (SQL) primitives and data types, current relational database systems to enable efficient data analysis tasks on scientific array-based data. It exploits a proprietary storage model jointly with a parallel software framework based on the Message Passing Interface (MPI) to run from single tasks to more complex dataflows. The current version of the Ophidia framework includes more than 60 array-based primitives and about 25 operators (16 parallel and 9 sequential). Among others, the available array-based functions allow to perform data sub-setting, data aggregation, array concatenation, algebraic expressions and predicate evaluation. Nesting is also supported. On the other hand, some relevant examples related to the parallel operators include (i) data sub-setting (slicing and dicing), (ii) data aggregation, (iii) array-based primitives, (iv) dataset duplication, (v) NetCDF-import and export. The Ophidia framework is being tested on NetCDF data produced in the context of the international Coupled Model Intercomparison Project Phase 5 (CMIP5) and available through the Earth System Grid Federation infrastructure. The current set of use cases includes: 1) data subsetting (e.g. slicing an dicing); 2) time series analysis (e.g. data summary and statistics); 3) data reduction (e.g. from daily to monthly, annual data); 4) data transformation (e.g. re-gridding); 5) data intercomparison (e.g. model and scenario intercomparison) 6) a composition of the aforementioned tasks. This work will highlight the most relevant architectural and infrastructural aspects of the Ophidia project, the parallel framework, the current set of

  14. Semi-automated De-identification of German Content Sensitive Reports for Big Data Analytics.

    Science.gov (United States)

    Seuss, Hannes; Dankerl, Peter; Ihle, Matthias; Grandjean, Andrea; Hammon, Rebecca; Kaestle, Nicola; Fasching, Peter A; Maier, Christian; Christoph, Jan; Sedlmayr, Martin; Uder, Michael; Cavallaro, Alexander; Hammon, Matthias

    2017-07-01

    reports enables reliable detection and labeling of sensitive data in different types of medical reports. Key Points:  · Collaborations between different institutions require de-identification of patients' data. · Software-based de-identification of content-sensitive reports grows in importance as a result of 'Big data'. · A de-identification software was developed and tested natively and after training. · The proposed de-identification software worked quite reliably, following training with roughly 100 edited reports. · A final check of the texts by an authorized person remains necessary. Citation Format · Seuss H, Dankerl P, Ihle M et al. Semi-automated De-identification of German Content Sensitive Reports for Big Data Analytics. Fortschr Röntgenstr 2017; 189: 661 - 671. © Georg Thieme Verlag KG Stuttgart · New York.

  15. Highly Sensitive Electro-Optic Modulators

    Energy Technology Data Exchange (ETDEWEB)

    DeVore, Peter S [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-10-26

    There are very important diagnostic and communication applications that receive faint electrical signals to be transmitted over long distances for capture. Optical links reduce bandwidth and distance restrictions of metal transmission lines; however, such signals are only weakly imprinted onto the optical carrier, resulting in low fidelity transmission. Increasing signal fidelity often necessitates insertion of radio-frequency (RF) amplifiers before the electro-optic modulator, but (especially at high frequencies) RF amplification results in large irreversible distortions. We have investigated the feasibility of a Sensitive and Linear Modulation by Optical Nonlinearity (SALMON) modulator to supersede RF-amplified modulators. SALMON uses cross-phase modulation, a manifestation of the Kerr effect, to enhance the modulation depth of an RF-modulated optical wave. This ultrafast process has the potential to result in less irreversible distortions as compared to a RF-amplified modulator due to the broadband nature of the Kerr effect. Here, we prove that a SALMON modulator is a feasible alternative to an RFamplified modulator, by demonstrating a sensitivity enhancement factor greater than 20 and significantly reduced distortion.

  16. Heterogeneous catalysis in highly sensitive microreactors

    DEFF Research Database (Denmark)

    Olsen, Jakob Lind

    This thesis present a highly sensitive silicon microreactor and examples of its use in studying catalysis. The experimental setup built for gas handling and temperature control for the microreactor is described. The implementation of LabVIEW interfacing for all the experimental parts makes...... automated experiments and data collection possible. An argon ush at the O-rings (used to interface the silicon microreactor with the gas system), which was developed, is presented. It enables experiments with temperatures up to 400., and up to 500. for short periods of time. The CO oxidation reaction...... of adsorbates readily converted to methanol as the source of the transient increase in methanol production, is eliminated. A study of mass selected ruthenium nanoparticles from a magnetron-sputter gas-aggregation source, deposited in microreactors, is presented. It is, shown that CO methanation can be measured...

  17. High-sensitivity fiber optic acoustic sensors

    Science.gov (United States)

    Lu, Ping; Liu, Deming; Liao, Hao

    2016-11-01

    Due to the overwhelming advantages compared with traditional electronicsensors, fiber-optic acoustic sensors have arisen enormous interest in multiple disciplines. In this paper we present the recent research achievements of our group on fiber-optic acoustic sensors. The main point of our research is high sensitivity interferometric acoustic sensors, including Michelson, Sagnac, and Fabry-Pérot interferometers. In addition, some advanced technologies have been proposed for acoustic or acoustic pressure sensing such as single-mode/multimode fiber coupler, dual FBGs and multi-longitudinal mode fiber laser based acoustic sensors. Moreover, our attention we have also been paid on signal demodulation schemes. The intensity-based quadrature point (Q-point) demodulation, two-wavelength quadrature demodulation and symmetric 3×3 coupler methodare discussed and compared in this paper.

  18. High sensitive radiation detector for radiology dosimetry

    Energy Technology Data Exchange (ETDEWEB)

    Valente, M.; Malano, F. [Instituto de Fisica Enrique Gaviola, Oficina 102 FaMAF - UNC, Av. Luis Medina Allende, Ciudad Universitaria, 5000 Cordoba (Argentina); Molina, W.; Vedelago, J., E-mail: valente@famac.unc.edu.ar [Laboratorio de Investigaciones e Instrumentacion en Fisica Aplicada a la Medicina e Imagenes por Rayos X, Laboratorio 448 FaMAF - UNC, Ciudad Universitaria, 5000 Cordoba (Argentina)

    2014-08-15

    Fricke solution has a wide range of applications as radiation detector and dosimetry. It is particularly appreciated in terms of relevant comparative advantages, like tissue equivalence when prepared in aqueous media like gel matrix, continuous mapping capability, dose rate recorded and incident direction independence as well as linear dose response. This work presents the development and characterization of a novel Fricke gel system, based on modified chemical compositions making possible its application in clinical radiology. Properties of standard Fricke gel dosimeter for high dose levels are used as starting point and suitable chemical modifications are introduced and carefully investigated in order to attain high resolution for low dose ranges, like those corresponding to radiology interventions. The developed Fricke gel radiation dosimeter system achieves the expected typical dose dependency, actually showing linear response in the dose range from 20 up to 4000 mGy. Systematic investigations including several chemical compositions are carried out in order to obtain a good enough dosimeter response for low dose levels. A suitable composition among those studied is selected as a good candidate for low dose level radiation dosimetry consisting on a modified Fricke solution fixed to a gel matrix containing benzoic acid along with sulfuric acid, ferrous sulfate, xylenol orange and ultra-pure reactive grade water. Dosimeter samples are prepared in standard vials for its in phantom irradiation and further characterization by spectrophotometry measuring visible light transmission and absorbance before and after irradiation. Samples are irradiated by typical kV X-ray tubes and calibrated Farmer type ionization chamber is used as reference to measure dose rates inside phantoms in at vials locations. Once sensitive material composition is already optimized, dose-response curves show significant improvement regarding overall sensitivity for low dose levels. According to

  19. [Highly sensitive detection technology for biological toxins applying sugar epitopes].

    Science.gov (United States)

    Uzawa, Hirotaka

    2009-01-01

    The Shiga toxin is a highly poisonous protein produced by enterohemorrhagic Escherichia coli O157. This bacterial toxin causes the hemolytic uremic syndrome. Another plant toxin from castor beans, ricin, is also highly toxic. The toxin was used for assassination in London. Recently, there were several cases of postal matter containing ricin. Both toxins are categorized as biological warfare agents by the Centers of Disease Control and Prevention. Conventional detection methods based on the antigen-antibody reaction, PCR and other cell-free assays have been proposed. However, those approaches have drawbacks in terms of sensitivity, analytical time, or stability of the detection reagents. Therefore, development of a facile and sensitive detection method is essential. Here we describe new detection methods applying carbohydrate epitopes as the toxin ligands, which is based on the fact that the toxins bind cell-surface oligosaccharides. Namely, the Shiga toxin has an affinity for globobiosyl (Gb(2)) disaccharide, and ricin binds the beta-D-galactose residue. For Shiga toxin detection, surface plasmon resonance (SPR) was applied. A polyanionic Gb(2)-glycopolymer was designed for this purpose, and it was used for the assembly of Gb(2)-chips using alternating layer-by-layer technology. The method allowed us to detect the toxin at a low concentration of LD(50). A synthetic carbohydrate ligand for ricin was designed and immobilized on the chips. SPR analysis with the chips allows us to detect ricin in a highly sensitive and facile manner (10 pg/ml, 5 min). Our present approaches provide a highly effective way to counter bioterrorism.

  20. High sensitivity field asymmetric ion mobility spectrometer

    Science.gov (United States)

    Chavarria, Mario A.; Matheoud, Alessandro V.; Marmillod, Philippe; Liu, Youjiang; Kong, Deyi; Brugger, Jürgen; Boero, Giovanni

    2017-03-01

    A high sensitivity field asymmetric ion mobility spectrometer (FAIMS) was designed, fabricated, and tested. The main components of the system are a 10.6 eV UV photoionization source, an ion filter driven by a high voltage/high frequency n-MOS inverter circuit, and a low noise ion detector. The ion filter electronics are capable to generate square waveforms with peak-to-peak voltages up to 1000 V at frequencies up to 1 MHz with adjustable duty cycles. The ion detector current amplifier has a gain up to 1012 V/A with an effective equivalent input noise level down to about 1 fA/Hz1/2 during operation with the ion filter at the maximum voltage and frequency. The FAIMS system was characterized by detecting different standard chemical compounds. Additionally, we investigated the use of a synchronous modulation/demodulation technique to improve the signal-to-noise ratio in FAIMS measurements. In particular, we implemented the modulation of the compensation voltage with the synchronous demodulation of the ion current. The analysis of the measurements at low concentration levels led to an extrapolated limit of detection for acetone of 10 ppt with an averaging time of 1 s.

  1. High Sensitivity 1-D and 2-D Microwave Spectroscopy via Cryogenic Buffer Gas Cooling

    Science.gov (United States)

    Patterson, David; Eibenberger, Sandra

    2017-06-01

    All rotationally resolved spectroscopic methods rely on sources of cold molecules. For the last three decades, the workhorse technique for producing highly supersaturated samples of cold molecules has been the pulsed supersonic jet. We present here progress on our alternative method, cryogenic buffer gas cooling. Our high density, continuous source, and low noise temperature allow us to record microwave spectra at unprecedented sensitivity, with a dynamic range in excess of 10^6 achievable in a few minutes of integration time. This high sensitivity enables new protocols in both 1-D and 2-D microwave spectroscopy, including sensitive chiral analysis via nonlinear three wave mixing and applications as an analytical chemistry tool

  2. High Sensitivity Refractive Index Sensor Based on Dual-Core Photonic Crystal Fiber with Hexagonal Lattice

    Directory of Open Access Journals (Sweden)

    Haiyang Wang

    2016-10-01

    Full Text Available A refractive index sensor based on dual-core photonic crystal fiber (PCF with hexagonal lattice is proposed. The effects of geometrical parameters of the PCF on performances of the sensor are investigated by using the finite element method (FEM. Two fiber cores are separated by two air holes filled with the analyte whose refractive index is in the range of 1.33–1.41. Numerical simulation results show that the highest sensitivity can be up to 22,983 nm/RIU(refractive index unit when the analyte refractive index is 1.41. The lowest sensitivity can reach to 21,679 nm/RIU when the analyte refractive index is 1.33. The sensor we proposed has significant advantages in the field of biomolecule detection as it provides a wide-range of detection with high sensitivity.

  3. High Sensitivity Refractive Index Sensor Based on Dual-Core Photonic Crystal Fiber with Hexagonal Lattice.

    Science.gov (United States)

    Wang, Haiyang; Yan, Xin; Li, Shuguang; An, Guowen; Zhang, Xuenan

    2016-10-08

    A refractive index sensor based on dual-core photonic crystal fiber (PCF) with hexagonal lattice is proposed. The effects of geometrical parameters of the PCF on performances of the sensor are investigated by using the finite element method (FEM). Two fiber cores are separated by two air holes filled with the analyte whose refractive index is in the range of 1.33-1.41. Numerical simulation results show that the highest sensitivity can be up to 22,983 nm/RIU(refractive index unit) when the analyte refractive index is 1.41. The lowest sensitivity can reach to 21,679 nm/RIU when the analyte refractive index is 1.33. The sensor we proposed has significant advantages in the field of biomolecule detection as it provides a wide-range of detection with high sensitivity.

  4. Innovative nanostructures for highly sensitive vibrational biosensing (Conference Presentation)

    Science.gov (United States)

    Popp, Juergen; Mayerhöfer, Thomas; Cialla-May, Dana; Weber, Karina; Huebner, Uwe

    2016-03-01

    Employing vibrational spectroscopy (IR-absorption and Raman spectroscopy) allows for the labelfree detection of molecular specific fingerprints of inorganic, organic and biological substances. The sensitivity of vibrational spectroscopy can be improved by several orders of magnitude via the application of plasmonic active surfaces. Within this contribution we will discuss two such approaches, namely surface enhanced Raman spectroscopy (SERS) as well as surface enhanced IR absorption (SEIRA). It will be shown that SERS using metal colloids as SERS active substrate in combination with a microfluidic lab-on-a-chip (LOC) device enables high throughput and reproducible measurements with highest sensitivity and specificity. The application of such a LOC-SERS approach for therapeutic drug monitoring (e.g. quantitative detection of antibiotics in a urine matrix) will be presented. Furthermore, we will introduce innovative bottom-up strategies to prepare SERS-active nanostructures coated with a lipophilic sensor layer as one-time use SERS substrates for specific food analysis (e.g. quantitative detection of toxic food colorants). The second part of this contribution presents a slit array metamaterial perfect absorber for IR sensing applications consisting of a dielectric layer sandwiched between two metallic layers of which the upper layer is perforated with a periodic array of slits. Light-matter interaction is greatly amplified in the slits, where also the analyte is concentrated, as the surface of the substrate is covered by a thin silica layer. Thus, already small concentrations of analytes down to a monolayer can be detected by refractive index sensing and identified by their spectral fingerprints with a standard mid-infrared lab spectrometer.

  5. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry

    Science.gov (United States)

    Montaser, A.

    This research follows a multifaceted approach, from theory to practice, to the investigation and development of novel helium plasmas, sample introduction systems, and diagnostic techniques for atomic and mass spectrometries. During the period January 1994 - December 1994, four major sets of challenging research programs were addressed that each included a number of discrete but complementary projects: (1) The first program is concerned with fundamental and analytical investigations of novel atmospheric-pressure helium inductively coupled plasmas (He ICPS) that are suitable for the atomization-excitation-ionization of elements, especially those possessing high excitation and ionization energies, for the purpose of enhancing sensitivity and selectivity of analytical measurements. (2) The second program includes simulation and computer modeling of He ICPS. The aim is to ease the hunt for new helium plasmas by predicting their structure and fundamental and analytical properties, without incurring the enormous cost for extensive experimental studies. (3) The third program involves spectroscopic imaging and diagnostic studies of plasma discharges to instantly visualize their prevailing structures, to quantify key fundamental properties, and to verify predictions by mathematical models. (4) The fourth program entails investigation of new, low-cost sample introduction systems that consume micro- to nanoliter quantity of sample solution in plasma spectrometries. A portion of this research involves development and applications of novel diagnostic techniques suitable for probing key fundamental properties of aerosol prior to and after injection into high-temperature plasmas. These efforts, still in progress, collectively offer promise of solving singularly difficult analytical problems that either exist now or are likely to arise in the future in the various fields of energy generation, environmental pollution, material science, biomedicine and nutrition.

  6. Highly sensitive direct conversion ultrasound interferometer

    Science.gov (United States)

    Svitelskiy, Oleksiy; Grossmann, John; Suslov, Alexey

    2015-03-01

    Being invented more than fifty years ago, the ultrasonic pulse-echo technique has proven itself as a valuable and indispensable non-destructive tool to explore elastic properties of materials in engineering and scientific tasks. We propose a new design for the instrument based on mass-produced integral microchips. In our design the radiofrequency echo-pulse signal is processed by AD8302 RF gain and phase detector (www.analog.com).Its phase output is linearly proportional to the phase difference between the exciting and response signals. The gain output is proportional to the log of the ratio of amplitudes of the received to the exciting signals. To exclude the non-linear fragments and to enable exploring large phase changes, we employ parallel connection of two detectors, fed by in-phase and quadrature signals respectively. The instrument allowed us exploring phase transitions with precision of ΔV / V ~10-7 (V is the ultrasound speed). The high sensitivity of the logarithmic amplifiers embedded into AD8302 requires good grounding and screening of the receiving circuitry.

  7. Highly sensitive methods for electroanalytical chemistry based on nanotubule membranes.

    Science.gov (United States)

    Kobayashi, Y; Martin, C R

    1999-09-01

    Two new methods of electroanalysis are described. These methods are based on membranes containing monodisperse Au nanotubules with inside diameters approaching molecular dimensions. In one method, the analyte species is detected by measuring the change in trans-membrane current when the analyte is added to the nanotubule-based cell. The second method entails the use of a concentration cell based on the nanotubule membrane. In this case, the change in membrane potential is used to detect the analyte. Detection limits as low as 10(-11) M have been achieved. Hence, these methods compete with even the most sensitive of modern analytical methodologies. In addition, excellent molecular-sized-based selectivity is observed.

  8. High Sensitivity, High Frequency and High Time Resolution Decimetric Spectroscope

    Science.gov (United States)

    Sawant, H. S.; Rosa, R. R.

    1990-11-01

    RESUMEN. Se ha desarrollado el primer espectroscopio decimetrico latino americano operando en una banda de 100 MHz con alta resoluci6n de fre- cuencia (100 KHz) y tiempo (10 ms), alrededor de cualquier centro de frecuencia en el intervalo de 2000-200 MHz. El prop6sito de esta nota es describir investigaciones solares y no solares que se planean, progra ma de investigaci6n y la situaci6n actual de desarrollo de este espectroscopio. ABSTRACT. First Latin American Decimetric Spectroscope operating over a band of 100 MHz with high resolution in frequency (100 KHz) and time (10 ms), around any center frequency in the range of 2000-200 MHz is being developed. The purpose of this note is to describe planned solar, and non-solar, research programmes and present status of development of this spectroscope. Keq wo : INSTRUMENTS - SPECTROSCOPY

  9. Nanometal particle reagents for sensitive, MEMS based fiber-optic, multi-analyte, immuno-biosensing

    Science.gov (United States)

    Hong, Bin

    Integration of nanotechnology to medical diagnostics has brought a new era to public health practice. An excellent example is the utilization of unique optoelectronic properties of nanoparticles to develop highly sensitive biosensing devices for point-of-care (POC) disease diagnosis/prognosis. Fluorophore mediated, immuno-biosensors are important disease detection tools. The property of intra-molecular fluorescence quenching of most fluorophores, however, limits the sensitivity of this type of sensors. A plasmon-rich nanometal particle (NMP) can transfer the lone pair electrons of a fluorophore, which normally participate in the fluorescence self-quenching, to its surface plasmon field, resulting in artificial fluorescence enhancement. The enhancement was found to depend on the metal type, the particle size, the distance between a particle and a fluorophore, and the quantum yield of a fluorophore. Some biocompatible solvents were also found to increase the fluorescence emission efficiency via effective dipole coupling between the fluorophore and the solvent molecule. The application of solvents in inmuno-sensing could additionally improve the fluorescence light retrieval by the conformational change of the protein complexes in solvent. The mixture of the NMP and the solvent, which we defined as nanometal particle reagent (NMPR), provided even higher enhancements. Cardiovascular diseases (CVDs) kill 1 person in every 6 seconds. Among the CVDs, acute myocardial infarction (AMI; commonly known as heart attack) is the most dangerous and time-sensitive killer. A rapid and accurate AMI diagnosis is crucial for saving many lives. For this purpose, a fluorophore mediated, immuno-reaction based, multi-cardiac-marker sensing device was developed, to quantify four myocardium-specific proteins simultaneously, accurately, rapidly, and user-friendly. The four cardiac markers of our choice were myoglobin (MG), C-reactive protein (CRP), cardiac troponin I (cTnI), and B

  10. High-Dimensional Topological Insulators with Quaternionic Analytic Landau Levels

    Science.gov (United States)

    Li, Yi; Wu, Congjun

    2013-05-01

    We study the three-dimensional topological insulators in the continuum by coupling spin-1/2 fermions to the Aharonov-Casher SU(2) gauge field. They exhibit flat Landau levels in which orbital angular momentum and spin are coupled with a fixed helicity. The three-dimensional lowest Landau level wave functions exhibit the quaternionic analyticity as a generalization of the complex analyticity of the two-dimensional case. Each Landau level contributes one branch of gapless helical Dirac modes to the surface spectra, whose topological properties belong to the Z2 class. The flat Landau levels can be generalized to an arbitrary dimension. Interaction effects and experimental realizations are also studied.

  11. Loading of red blood cells with an analyte-sensitive dye for development of a long-term monitoring technique

    Science.gov (United States)

    Ritter, Sarah C.; Meissner, Kenith E.

    2012-03-01

    Measurement of blood analytes, such as pH and glucose, provide crucial information about a patient's health. Some such analytes, such as glucose in the case of diabetes, require long-term or near-continuous monitoring for proper disease management. However, current monitoring techniques are far from ideal: multiple-per-day finger stick tests are inconvenient and painful for the patient; implantable sensors have short functional life spans (i.e., 3-7 days). Red blood cells serve as an attractive alternative for carriers of analyte sensors. Once reintroduced to the blood stream, these carriers may continue to live for the remainder of their life span (120 days for humans). They are also biodegradable and biocompatible, thereby eliminating the immune system response common for many implanted devices. The proposed carrier system takes advantage of the ability of the red blood cells to swell in response to a decrease in the osmolarity of the extracellular solution. Just before the membranes lyse, they develop small pores on the scale of tens of nanometers. Analyte-sensitive dyes in the extracellular solution may then diffuse into the perforated red blood cells and become entrapped upon restoration of physiological temperature and osmolarity. Because the membranes contain various analyte transporters, intracellular analyte levels rapidly equilibrate to those of the extracellular solution. A fluorescent dye has been loaded inside of red blood cells using a preswelling technique. Alterations in preparation parameters have been shown to affect characteristics of the resulting dye-loaded red blood cells (e.g., intensity of fluorescence).

  12. Evaluation of analytical methodology for hydrocarbons in high pressure air and nitrogen systems. [evaluation of methodology

    Science.gov (United States)

    1977-01-01

    Samples of liquid oxygen, high pressure nitrogen, low pressure nitrogen, and missile grade air were studied to determine the hydrocarbon concentrations. Concentration of the samples was achieved by adsorption on a molecular sieve and activated charcoal. The trapped hydrocarbons were then desorbed and transferred to an analytical column in a gas chromatograph. The sensitivity of the method depends on the volume of gas passed through the adsorbent tubes. The value of the method was verified through recoverability and reproducibility studies. The use of this method enables LOX, GN2, and missile grade air systems to be routinely monitored to determine low level increases in specific hydrocarbon concentration that could lead to potentially hazardous conditions.

  13. [A simple highly sensitive recording microspectrophotometer].

    Science.gov (United States)

    Govardovskiĭ, V I; Zueva, L V

    1988-04-01

    A design of the recording microspectrophotometer is described. The instrument possesses an absolutely flat base line and quantum-noise limited detection threshold. Two principal elements of the design are the "jumping" stage, and the logarithmic amplifier with the phase-sensitive detector which converts the photomultiplier output into the optical density signal. The performance of the instrument is illustrated by the recordings of visual pigment spectra in single photoreceptors.

  14. High-latitude ionospheric outflows characterized through analytic formulas

    Science.gov (United States)

    Zeng, W.; Horwitz, J. L.

    2008-12-01

    Recent advances involving multi-fluid treatments have begun to allow the prospect of global magnetospheric models to simulate the dynamics of multiple ion species, such as various ion species originating from sources in the solar wind and terrestrial ionosphere. Such opportunities for the dynamic treatment of ionospheric ions within the magnetosphere portend a need for realistic accessible methods of estimating ionospheric outflows as linked plasma sources for these global models. Toward this end, in this presentation, the results of numerous physics-based simulations of ionospheric plasma outflows under varied driving agents are distilled in terms of relatively compact analytic expressions. The simulations are conducted with the UT Arlington Dynamic Fluid (DyFK) ionospheric plasma transport code. These analytic expressions for O+ and H+ densities, temperatures and flow velocities are obtained at the 3 RE altitudes corresponding to typical inner boundary levels for certain current global magnetospheric models. These O+ and H+ parameters are expressed as functions of precipitation electron energy flux levels, characteristic energy levels of the precipitating electrons, the peak spectral wave densities for low-frequency electrostatic waves which transversely heat ionospheric ions, and solar zenith angle.

  15. Analytical Study of the Effect of the System Geometry on Photon Sensitivity and Depth of Interaction of Positron Emission Mammography

    Directory of Open Access Journals (Sweden)

    Pablo Aguiar

    2012-01-01

    Full Text Available Positron emission mammography (PEM cameras are novel-dedicated PET systems optimized to image the breast. For these cameras it is essential to achieve an optimum trade-off between sensitivity and spatial resolution and therefore the main challenge for the novel cameras is to improve the sensitivity without degrading the spatial resolution. We carry out an analytical study of the effect of the different detector geometries on the photon sensitivity and the angle of incidence of the detected photons which is related to the DOI effect and therefore to the intrinsic spatial resolution. To this end, dual head detectors were compared to box and different polygon-detector configurations. Our results showed that higher sensitivity and uniformity were found for box and polygon-detector configurations compared to dual-head cameras. Thus, the optimal configuration in terms of sensitivity is a PEM scanner based on a polygon of twelve (dodecagon or more detectors. We have shown that this configuration is clearly superior to dual-head detectors and slightly higher than box, octagon, and hexagon detectors. Nevertheless, DOI effects are increased for this configuration compared to dual head and box scanners and therefore an accurate compensation for this effect is required.

  16. Anxiety Sensitivity and the Anxiety Disorders: A Meta-Analytic Review and Synthesis

    Science.gov (United States)

    Olatunji, Bunmi O.; Wolitzky-Taylor, Kate B.

    2009-01-01

    There has been significant interest in the role of anxiety sensitivity (AS) in the anxiety disorders. In this meta-analysis, we empirically evaluate differences in AS between anxiety disorders, mood disorders, and nonclinical controls. A total of 38 published studies (N = 20,146) were included in the analysis. The results yielded a large effect…

  17. Radionuclide migration through fractured rock for arbitrary-length decay chain: Analytical solution and global sensitivity analysis

    Science.gov (United States)

    Shahkarami, Pirouz; Liu, Longcheng; Moreno, Luis; Neretnieks, Ivars

    2015-01-01

    This study presents an analytical approach to simulate nuclide migration through a channel in a fracture accounting for an arbitrary-length decay chain. The nuclides are retarded as they diffuse in the porous rock matrix and stagnant zones in the fracture. The Laplace transform and similarity transform techniques are applied to solve the model. The analytical solution to the nuclide concentrations at the fracture outlet is governed by nine parameters representing different mechanisms acting on nuclide transport through a fracture, including diffusion into the rock matrices, diffusion into the stagnant water zone, chain decay and hydrodynamic dispersion. Furthermore, to assess how sensitive the results are to parameter uncertainties, the Sobol method is applied in variance-based global sensitivity analyses of the model output. The Sobol indices show how uncertainty in the model output is apportioned to the uncertainty in the model input. This method takes into account both direct effects and interaction effects between input parameters. The simulation results suggest that in the case of pulse injections, ignoring the effect of a stagnant water zone can lead to significant errors in the time of first arrival and the peak value of the nuclides. Likewise, neglecting the parent and modeling its daughter as a single stable species can result in a significant overestimation of the peak value of the daughter nuclide. It is also found that as the dispersion increases, the early arrival time and the peak time of the daughter decrease while the peak value increases. More importantly, the global sensitivity analysis reveals that for time periods greater than a few thousand years, the uncertainty of the model output is more sensitive to the values of the individual parameters than to the interaction between them. Moreover, if one tries to evaluate the true values of the input parameters at the same cost and effort, the determination of priorities should follow a certain

  18. High-Sensitivity GaN Microchemical Sensors

    Science.gov (United States)

    Son, Kyung-ah; Yang, Baohua; Liao, Anna; Moon, Jeongsun; Prokopuk, Nicholas

    2009-01-01

    Systematic studies have been performed on the sensitivity of GaN HEMT (high electron mobility transistor) sensors using various gate electrode designs and operational parameters. The results here show that a higher sensitivity can be achieved with a larger W/L ratio (W = gate width, L = gate length) at a given D (D = source-drain distance), and multi-finger gate electrodes offer a higher sensitivity than a one-finger gate electrode. In terms of operating conditions, sensor sensitivity is strongly dependent on transconductance of the sensor. The highest sensitivity can be achieved at the gate voltage where the slope of the transconductance curve is the largest. This work provides critical information about how the gate electrode of a GaN HEMT, which has been identified as the most sensitive among GaN microsensors, needs to be designed, and what operation parameters should be used for high sensitivity detection.

  19. An overview of the environmental applicability of vermicompost: from wastewater treatment to the development of sensitive analytical methods.

    Science.gov (United States)

    Pereira, Madson de Godoi; Neta, Lourdes Cardoso de Souza; Fontes, Maurício Paulo Ferreira; Souza, Adriana Nascimento; Matos, Thaionara Carvalho; Sachdev, Raquel de Lima; dos Santos, Arnaud Victor; da Guarda Souza, Marluce Oliveira; de Andrade, Marta Valéria Almeida Santana; Paulo, Gabriela Marinho Maciel; Ribeiro, Joselito Nardy; Ribeiro, Araceli Verónica Flores Nardy

    2014-01-01

    The use of vermicompost (humified material) for treating wastewaters, remediating polluted soils, improving agricultural productivity, protecting crop production, and developing sensitive analytical methods is reviewed here, covering the past 17 years. The main advantages of vermicompost, considering all applications covered in this paper, comprise (i) easy acquisition, (ii) low costs, (iii) structural, chemical, and biological characteristics responsible for exceptional adsorptive capacities as well as pollutant degradation, and (iv) the promotion of biocontrol. Specifically, for wastewater decontamination, a considerable number of works have verified the adsorption of toxic metals, but the application of vermicompost is still scarce for the retention of organic compounds. Problems related to the final disposal of enriched vermicompost (after treatment steps) are often found, in spite of some successful destinations such as organic fertilizer. For decontaminating soils, the use of vermicompost is quite scarce, mainly for inorganic pollutants. In agricultural productivity and biocontrol, vermicompost imparts remarkable benefits regarding soil aggregation, plant nutrition, and the development of beneficial microorganisms against phytopathogens. Finally, the use of vermicompost in sensitive analytical methods for quantifying toxic metals is the newest application of this adsorbent.

  20. An Overview of the Environmental Applicability of Vermicompost: From Wastewater Treatment to the Development of Sensitive Analytical Methods

    Directory of Open Access Journals (Sweden)

    Madson de Godoi Pereira

    2014-01-01

    Full Text Available The use of vermicompost (humified material for treating wastewaters, remediating polluted soils, improving agricultural productivity, protecting crop production, and developing sensitive analytical methods is reviewed here, covering the past 17 years. The main advantages of vermicompost, considering all applications covered in this paper, comprise (i easy acquisition, (ii low costs, (iii structural, chemical, and biological characteristics responsible for exceptional adsorptive capacities as well as pollutant degradation, and (iv the promotion of biocontrol. Specifically, for wastewater decontamination, a considerable number of works have verified the adsorption of toxic metals, but the application of vermicompost is still scarce for the retention of organic compounds. Problems related to the final disposal of enriched vermicompost (after treatment steps are often found, in spite of some successful destinations such as organic fertilizer. For decontaminating soils, the use of vermicompost is quite scarce, mainly for inorganic pollutants. In agricultural productivity and biocontrol, vermicompost imparts remarkable benefits regarding soil aggregation, plant nutrition, and the development of beneficial microorganisms against phytopathogens. Finally, the use of vermicompost in sensitive analytical methods for quantifying toxic metals is the newest application of this adsorbent.

  1. Boron doped diamond sensor for sensitive determination of metronidazole: Mechanistic and analytical study by cyclic voltammetry and square wave voltammetry

    Energy Technology Data Exchange (ETDEWEB)

    Ammar, Hafedh Belhadj, E-mail: hbelhadjammar@yahoo.fr; Brahim, Mabrouk Ben; Abdelhédi, Ridha; Samet, Youssef

    2016-02-01

    The performance of boron-doped diamond (BDD) electrode for the detection of metronidazole (MTZ) as the most important drug of the group of 5-nitroimidazole was proven using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. A comparison study between BDD, glassy carbon and silver electrodes on the electrochemical response was carried out. The process is pH-dependent. In neutral and alkaline media, one irreversible reduction peak related to the hydroxylamine derivative formation was registered, involving a total of four electrons. In acidic medium, a prepeak appears probably related to the adsorption affinity of hydroxylamine at the electrode surface. The BDD electrode showed higher sensitivity and reproducibility analytical response, compared with the other electrodes. The higher reduction peak current was registered at pH 11. Under optimal conditions, a linear analytical curve was obtained for the MTZ concentration in the range of 0.2–4.2 μmol L{sup −1}, with a detection limit of 0.065 μmol L{sup −1}. - Highlights: • SWV for the determination of MTZ • Boron-doped diamond as a new electrochemical sensor • Simple and rapid detection of MTZ • Efficiency of BDD for sensitive determination of MTZ.

  2. Highly sensitive ammonia sensor using reflection of light at a glass - photonic crystal interface

    CERN Document Server

    Kuchyanov, A S; Spisser, H; Plekhanov, A I

    2013-01-01

    We have discovered and studied the effect of the asymmetric deformation of a photonic crystal in the form of a change in the slope of the crystal planes as it is filled with a gaseous analyte. We have demonstrated that the use of a new effect leading to the displacement of the stop band against the unchanged spectrum of diffracted white light at the (glass-thin opal film) interface can be used as fast, compact, high sensitive and reproducible optical chemical sensor for ammonia. Low cost and simplicity of sensor fabrication, the response of which can be easily observed without resorting to spectral instruments are therefore likely to be attractive. The basis for high sensitivity (1 ppm), fast response (120 ms) is capillary vapor condensation. On the basis of this effect a cheap high-speed and highly sensitive gas sensors has been built.

  3. Triggers for a high sensitivity charm experiment

    Energy Technology Data Exchange (ETDEWEB)

    Christian, D.C.

    1994-07-01

    Any future charm experiment clearly should implement an E{sub T} trigger and a {mu} trigger. In order to reach the 10{sup 8} reconstructed charm level for hadronic final states, a high quality vertex trigger will almost certainly also be necessary. The best hope for the development of an offline quality vertex trigger lies in further development of the ideas of data-driven processing pioneered by the Nevis/U. Mass. group.

  4. Sensitivity of fish density estimates to standard analytical procedures applied to Great Lakes hydroacoustic data

    Science.gov (United States)

    Kocovsky, Patrick M.; Rudstam, Lars G.; Yule, Daniel L.; Warner, David M.; Schaner, Ted; Pientka, Bernie; Deller, John W.; Waterfield, Holly A.; Witzel, Larry D.; Sullivan, Patrick J.

    2013-01-01

    Standardized methods of data collection and analysis ensure quality and facilitate comparisons among systems. We evaluated the importance of three recommendations from the Standard Operating Procedure for hydroacoustics in the Laurentian Great Lakes (GLSOP) on density estimates of target species: noise subtraction; setting volume backscattering strength (Sv) thresholds from user-defined minimum target strength (TS) of interest (TS-based Sv threshold); and calculations of an index for multiple targets (Nv index) to identify and remove biased TS values. Eliminating noise had the predictable effect of decreasing density estimates in most lakes. Using the TS-based Sv threshold decreased fish densities in the middle and lower layers in the deepest lakes with abundant invertebrates (e.g., Mysis diluviana). Correcting for biased in situ TS increased measured density up to 86% in the shallower lakes, which had the highest fish densities. The current recommendations by the GLSOP significantly influence acoustic density estimates, but the degree of importance is lake dependent. Applying GLSOP recommendations, whether in the Laurentian Great Lakes or elsewhere, will improve our ability to compare results among lakes. We recommend further development of standards, including minimum TS and analytical cell size, for reducing the effect of biased in situ TS on density estimates.

  5. Increasing the analytical sensitivity by oligonucleotides modified with para- and ortho-twisted intercalating nucleic acids--TINA.

    Directory of Open Access Journals (Sweden)

    Uffe V Schneider

    Full Text Available The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators. Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para-TINA molecules increased the melting point (Tm of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5' and 3' termini (preferable or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved analytical sensitivity in a DNA hybridization capture assay targeting the Escherichia coli rrs gene. The corresponding sequence from the Pseudomonas aeruginosa rrs gene was used as cross-reactivity control. At 150 mM ionic strength, analytical sensitivity was improved 27-fold by addition of ortho-TINA molecules and 7-fold by addition of para-TINA molecules (versus the unmodified DNA oligonucleotide, with a 4-fold increase retained at 1 M ionic strength. Both intercalators sustained the discrimination of mismatches in the dsDNA (indicated by ΔTm, unless placed directly adjacent to the mismatch--in which case they partly concealed ΔTm (most pronounced for para-TINA molecules. We anticipate that the presented rules for placement of TINA molecules will be broadly applicable in hybridization capture assays and target amplification systems.

  6. Increasing the Analytical Sensitivity by Oligonucleotides Modified with Para- and Ortho-Twisted Intercalating Nucleic Acids – TINA

    Science.gov (United States)

    Schneider, Uffe V.; Géci, Imrich; Jøhnk, Nina; Mikkelsen, Nikolaj D.; Pedersen, Erik B.; Lisby, Gorm

    2011-01-01

    The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators. Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para-TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5′ and 3′ termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved analytical sensitivity in a DNA hybridization capture assay targeting the Escherichia coli rrs gene. The corresponding sequence from the Pseudomonas aeruginosa rrs gene was used as cross-reactivity control. At 150 mM ionic strength, analytical sensitivity was improved 27-fold by addition of ortho-TINA molecules and 7-fold by addition of para-TINA molecules (versus the unmodified DNA oligonucleotide), with a 4-fold increase retained at 1 M ionic strength. Both intercalators sustained the discrimination of mismatches in the dsDNA (indicated by ΔTm), unless placed directly adjacent to the mismatch – in which case they partly concealed ΔTm (most pronounced for para-TINA molecules). We anticipate that the presented rules for placement of TINA molecules will be broadly applicable in hybridization capture assays and target amplification systems. PMID:21673988

  7. Scalloped electrodes for highly sensitive electrical measurements

    DEFF Research Database (Denmark)

    Vazquez Rodriguez, Patricia; Dimaki, Maria; Svendsen, Winnie Edith

    2011-01-01

    In this work we introduce a novel out-of-plane electrode with pronounced scalloped surface and high aspect ratio for electrical recordings of brain tissue in vitro, with the aim to reduce significantly the impedance of the measuring system. The profile and height of the structures is tailored...... by means of silicon fabrication techniques that sharpen them progressively and in a controlled manner. We will show that the use of the scalloped area achieves a great decrease in impedance, which is very significant for a reduction of noise in electrical measurements. The measured impedance reflects...

  8. The validation of an analytical method for sulfentrazone residue determination in soil using liquid chromatography and a comparison of chromatographic sensitivity to millet as a bioindicator species.

    Science.gov (United States)

    de Oliveira, Marcelo Antonio; Pires, Fábio Ribeiro; Ferraço, Mariana; Belo, Alessandra Ferreira

    2014-07-28

    Commonly used herbicides, such as sulfentrazone, pose the risk of soil contamination due to their persistence, bioaccumulation and toxicity. Phytoremediation by green manure species has been tested using biomarkers, but analytical data are now required to confirm the extraction of sulfentrazone from soil. Thus, the present work was carried out to analyze sulfentrazone residues in soil based on liquid chromatography with a comparison of these values to the sensitivity of the bioindicator Pennisetum glaucum. The soil samples were obtained after cultivation of Crotalaria juncea and Canavalia ensiformis at four seeding densities and with three doses of sulfentrazone. The seedlings were collected into pots, at two different depths, after 75 days of phytoremediator sowing and then were used to determine the herbicide persistence in the soil. A bioassay with P. glaucum was carried out in the same pot. High-performance liquid chromatography (HPLC), using UV-diode array detection (HPLC/UV-DAD), was used to determine the herbicide residues. The HPLC determination was optimized and validated according to the parameters of precision, accuracy, linearity, limit of detection and quantification, robustness and specificity. The bioindicator P. glaucum was more sensitive to sulfentrazone than residue determination by HPLC. Changes in sulfentrazone concentration caused by green manure phytoremediation were accurately identified by the bioindicator. However, a true correlation between the size of the species and the analyte content was not identified.

  9. The Validation of an Analytical Method for Sulfentrazone Residue Determination in Soil Using Liquid Chromatography and a Comparison of Chromatographic Sensitivity to Millet as a Bioindicator Species

    Directory of Open Access Journals (Sweden)

    Marcelo Antonio de Oliveira

    2014-07-01

    Full Text Available Commonly used herbicides, such as sulfentrazone, pose the risk of soil contamination due to their persistence, bioaccumulation and toxicity. Phytoremediation by green manure species has been tested using biomarkers, but analytical data are now required to confirm the extraction of sulfentrazone from soil. Thus, the present work was carried out to analyze sulfentrazone residues in soil based on liquid chromatography with a comparison of these values to the sensitivity of the bioindicator Pennisetum glaucum. The soil samples were obtained after cultivation of Crotalaria juncea and Canavalia ensiformis at four seeding densities and with three doses of sulfentrazone. The seedlings were collected into pots, at two different depths, after 75 days of phytoremediator sowing and then were used to determine the herbicide persistence in the soil. A bioassay with P. glaucum was carried out in the same pot. High-performance liquid chromatography (HPLC, using UV-diode array detection (HPLC/UV-DAD, was used to determine the herbicide residues. The HPLC determination was optimized and validated according to the parameters of precision, accuracy, linearity, limit of detection and quantification, robustness and specificity. The bioindicator P. glaucum was more sensitive to sulfentrazone than residue determination by HPLC. Changes in sulfentrazone concentration caused by green manure phytoremediation were accurately identified by the bioindicator. However, a true correlation between the size of the species and the analyte content was not identified.

  10. Novel Analytic Method for Determining Micro-Doppler Measurement Sensitivity in Life-detection Radar

    Directory of Open Access Journals (Sweden)

    Hu Cheng

    2016-10-01

    Full Text Available In recent years, a new non-contact life detecting device has been developed, known as life-detection radar, which can measure bodily movement and locate human subjects. Typically, the amplitude of the vibration being measured is quite small, so the measurement is easily contaminated by noise in the radar system. To date, there is no effective index for judging the influence of noise on the vibration measurements in this radar system. To solve this problem, in this paper, we define the micro-Doppler measurement sensitivity to analyze the influence of noise on the measurement. We then perform a simulation to generate a performance curve for the radar system.

  11. Multipurpose High Sensitivity Radiation Detector: Terradex

    Energy Technology Data Exchange (ETDEWEB)

    Alpat, Behcet [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy)]. E-mail: behcet.alpat@pg.infn.it; Aisa, Damiano [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Bizzarri, Marco [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Blasko, Sandor [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Esposito, Gennaro [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Farnesini, Lucio [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Fiori, Emmanuel [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Papi, Andrea [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Postolache, Vasile [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Renzi, Francesca [Dipartimento di Fisica dell' Universita di Perugia and INFN Sezione di Perugia (Italy); Ionica, Romeo [Politecnica University of Bucarest, Splaiul Indipendentei, Bucharest (Romania); Manolescu, Florentina [Space Science Institute of Bucharest, Maugurele, Bucharest (Romania); Ozkorucuklu, Suat [Suleyman Demirel Universitesi, Isparta (Turkey); Denizli, Haluk [Abant Izzet Baysal Universitesi, Bolu (Turkey); Tapan, Ilhan [Uludag Universitesi, Bursa (Turkey); Ercan Pilicer [Uludag Universitesi, Bursa (Turkey); Egidi, Felice [SITE Technology, Carsoli (Italy); Moretti, Cesare [SITE Technology, Carsoli(AQ) (Italy); Dicola, Luca [SITE Technology, Carsoli(AQ) (Italy)

    2007-05-11

    Terradex project aims to realise an accurate and programmable multiparametric tool which will measure relevant physical quantities such as observation time, energy and type of all decay products of three naturally occurring decay chains of uranium and thorium series present in nature as well as the decay products of man-made radioactivity. The measurements described in this work are based on the performance tests of the first version of an instrument that is designed to provide high counting accuracy, by introducing self-triggering, delayed time-coincidence technique, of products of a given decay chain. In order to qualify the technique and to calibrate the Terradex, a {sup 222}Rn source is used. The continuous and accurate monitoring of radon concentration in air is realised by observing the alpha and beta particles produced by the decay of {sup 222}Rn and its daughters and tag each of them with a precise occurrence time. The validity of delayed coincident technique by using the state of the art electronics with application of novel data sampling and analysis methods are discussed. The flexibility of sampling protocols and the advantages of online calibration capability to achieve the highest level of precision in natural and man-made radiation measurements are also described.

  12. Sample handling in surface sensitive chemical and biological sensing: a practical review of basic fluidics and analyte transport.

    Science.gov (United States)

    Orgovan, Norbert; Patko, Daniel; Hos, Csaba; Kurunczi, Sándor; Szabó, Bálint; Ramsden, Jeremy J; Horvath, Robert

    2014-09-01

    This paper gives an overview of the advantages and associated caveats of the most common sample handling methods in surface-sensitive chemical and biological sensing. We summarize the basic theoretical and practical considerations one faces when designing and assembling the fluidic part of the sensor devices. The influence of analyte size, the use of closed and flow-through cuvettes, the importance of flow rate, tubing length and diameter, bubble traps, pressure-driven pumping, cuvette dead volumes, and sample injection systems are all discussed. Typical application areas of particular arrangements are also highlighted, such as the monitoring of cellular adhesion, biomolecule adsorption-desorption and ligand-receptor affinity binding. Our work is a practical review in the sense that for every sample handling arrangement considered we present our own experimental data and critically review our experience with the given arrangement. In the experimental part we focus on sample handling in optical waveguide lightmode spectroscopy (OWLS) measurements, but the present study is equally applicable for other biosensing technologies in which an analyte in solution is captured at a surface and its presence is monitored. Explicit attention is given to features that are expected to play an increasingly decisive role in determining the reliability of (bio)chemical sensing measurements, such as analyte transport to the sensor surface; the distorting influence of dead volumes in the fluidic system; and the appropriate sample handling of cell suspensions (e.g. their quasi-simultaneous deposition). At the appropriate places, biological aspects closely related to fluidics (e.g. cellular mechanotransduction, competitive adsorption, blood flow in veins) are also discussed, particularly with regard to their models used in biosensing.

  13. Boron doped diamond sensor for sensitive determination of metronidazole: Mechanistic and analytical study by cyclic voltammetry and square wave voltammetry.

    Science.gov (United States)

    Ammar, Hafedh Belhadj; Brahim, Mabrouk Ben; Abdelhédi, Ridha; Samet, Youssef

    2016-02-01

    The performance of boron-doped diamond (BDD) electrode for the detection of metronidazole (MTZ) as the most important drug of the group of 5-nitroimidazole was proven using cyclic voltammetry (CV) and square wave voltammetry (SWV) techniques. A comparison study between BDD, glassy carbon and silver electrodes on the electrochemical response was carried out. The process is pH-dependent. In neutral and alkaline media, one irreversible reduction peak related to the hydroxylamine derivative formation was registered, involving a total of four electrons. In acidic medium, a prepeak appears probably related to the adsorption affinity of hydroxylamine at the electrode surface. The BDD electrode showed higher sensitivity and reproducibility analytical response, compared with the other electrodes. The higher reduction peak current was registered at pH11. Under optimal conditions, a linear analytical curve was obtained for the MTZ concentration in the range of 0.2-4.2μmolL(-1), with a detection limit of 0.065μmolL(-1). Copyright © 2015 Elsevier B.V. All rights reserved.

  14. Multi-analyte high performance liquid chromatography coupled to high resolution tandem mass spectrometry method for control of pesticide residues, mycotoxins, and pyrrolizidine alkaloids.

    Science.gov (United States)

    Dzuman, Zbynek; Zachariasova, Milena; Veprikova, Zdenka; Godula, Michal; Hajslova, Jana

    2015-03-10

    A new reliable and highly sensitive method based on high performance liquid chromatographic (HPLC) separation and high resolution tandem mass spectrometric detection (HRMS/MS) has been developed and validated for determination of 323 pesticide residues, 55 mycotoxins, and 11 plant toxins represented by pyrrolizidine alkaloids. The method was validated for three matrices, leek, wheat, and tea differing in nature/amount of co-extracts that may cause various matrix effects. For target analytes isolation, optimized QuEChERS-based (quick, easy, cheap, effective, rugged, and safe) extraction procedure was employed. Spectral HRMS/MS library has been established providing an entire spectrum of fragment ions for each analyte, which allows unbiased identification and confirmation of target compounds. The limits of quantification (LOQs) of target analytes were below 10 μg kg(-1) for 82%, 81%, and 61% for matrices leek, wheat, and tea, respectively. Recoveries were in the acceptable range (70-120%) according to SANCO/12571/2013 for most of target analytes, except for highly polar 'masked' mycotoxin deoxynivalenol-3-glucoside with recoveries 35%, 47%, and 42% for matrices leek, wheat, and tea, respectively. The linearities of calibration curves expressed as coefficients of determination were in the range of 0.9661-1.000, and repeatabilities expressed as relative standard deviations (RSDs) at LOQs lied in the range of 0.25-13.51%. The trueness of the method was verified using several certified reference materials (CRMs) and proficiency test samples.

  15. Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity

    Science.gov (United States)

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

    This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.

  16. Design optimization of high pressure and high temperature piezoresistive pressure sensor for high sensitivity.

    Science.gov (United States)

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

    This paper describes a design method for optimizing sensitivity of piezoresistive pressure sensor in high-pressure and high-temperature environment. In order to prove the method, a piezoresistive pressure sensor (HPTSS) is designed. With the purpose of increasing sensitivity and to improve the measurement range, the piezoresistive sensor adopts rectangular membrane and thick film structure. The configuration of piezoresistors is arranged according to the characteristic of the rectangular membrane. The structure and configuration of the sensor chip are analyzed theoretically and simulated by the finite element method. This design enables the sensor chip to operate in high pressure condition (such as 150 MPa) with a high sensitivity and accuracy. The silicon on insulator wafer is selected to guarantee the thermo stability of the sensor chip. In order to optimize the fabrication and improve the yield of production, an electric conduction step is devised. Series of experiments demonstrates a favorable linearity of 0.13% and a high accuracy of 0.48%. And the sensitivity of HTPSS is about six times as high as a conventional square-membrane sensor chip in the experiment. Compared with the square-membrane pressure sensor and current production, the strength of HPTTS lies in sensitivity and measurement. The performance of the HPTSS indicates that it could be an ideal candidate for high-pressure and high-temperature sensing in real application.

  17. A highly sensitive colorimetric and ratiometric sensor for fluoride ion

    Institute of Scientific and Technical Information of China (English)

    Zhao Wu Xu; Jin Tang; He Tian

    2008-01-01

    A new benzoimidazole-naphthalimide derivative 4 was synthesized and its photophysical properties were studied.This compound showed highly selectively and sensitive colorimetric and ratiometric sensing ability for fluoride anion.

  18. A Highly Sensitive Gold-Coated Photonic Crystal Fiber Biosensor Based on Surface Plasmon Resonance

    Directory of Open Access Journals (Sweden)

    Md. Rabiul Hasan

    2017-03-01

    Full Text Available In this paper, we numerically demonstrate a two-layer circular lattice photonic crystal fiber (PCF biosensor based on the principle of surface plasmon resonance (SPR. The finite element method (FEM with circular perfectly matched layer (PML boundary condition is applied to evaluate the performance of the proposed sensor. A thin gold layer is deposited outside the PCF structure, which acts as the plasmonic material for this design. The sensing layer (analyte is implemented in the outermost layer, which permits easy and more practical fabrication process compared to analyte is put inside the air holes. It is demonstrated that, at gold layer thickness of 40 nm, the proposed sensor shows maximum sensitivity of 2200 nm/RIU using the wavelength interrogation method in the sensing range between 1.33–1.36. Besides, using an amplitude interrogation method, a maximum sensitivity of 266 RIU−1 and a maximum sensor resolution of 3.75 × 10−5 RIU are obtained. We also discuss how phase matching points are varied with different fiber parameters. Owing to high sensitivity and simple design, the proposed sensor may find important applications in biochemical and biological analyte detection.

  19. Analytical possibilities of highly focused ion beams in biomedical field

    Science.gov (United States)

    Ren, M. Q.; Ji, X.; Vajandar, S. K.; Mi, Z. H.; Hoi, A.; Walczyk, T.; van Kan, J. A.; Bettiol, A. A.; Watt, F.; Osipowicz, T.

    2017-09-01

    At the Centre for Ion Beam Applications (CIBA), a 3.5 MV HVEE Singletron™ accelerator serves to provide MeV ion beams (mostly protons or He+) to six state-of-the-art beam lines, four of which are equipped with Oxford triplet magnetic quadrupole lens systems. This facility is used for a wide range of research projects, many of which are in the field of biomedicine. Here we presented a discussion of currently ongoing biomedical work carried out using two beamlines: The Nuclear Microscopy (NM) beamline is mainly used for trace elemental quantitative mapping using a combination of Particle Induced X-ray Emission (PIXE), to measure the trace elemental concentration of inorganic elements, Rutherford Backscattering Spectrometry (RBS), to characterise the organic matrix, and Scanning Transmission Ion Microscopy (STIM) to provide information on the lateral areal density variations of the specimen. Typically, a 2.1 MeV proton beam, focused to 1-2 μm spot size with a current of 100 pA is used. The high resolution single cell imaging beamline is equipped with direct STIM to image the interior structure of single cells with proton and alpha particles of sub-50 nm beam spot sizes. Simultaneously, forward scattering transmission ion microscopy (FSTIM) is utilized to generate images with improved contrast of nanoparticles with higher atomic numbers, such as gold nanoparticles, and fluorescent nanoparticles can be imaged using Proton Induced Fluorescence (PIF). Lastly, in this facility, RBS has been included as an option if required to determine the depth distribution of nanoparticles in cells, albeit with reduced spatial resolution.

  20. Relative analytical sensitivity of donor nucleic acid amplification technology screening and diagnostic real-time polymerase chain reaction assays for detection of Zika virus RNA.

    Science.gov (United States)

    Stone, Mars; Lanteri, Marion C; Bakkour, Sonia; Deng, Xutao; Galel, Susan A; Linnen, Jeffrey M; Muñoz-Jordán, Jorge L; Lanciotti, Robert S; Rios, Maria; Gallian, Pierre; Musso, Didier; Levi, José E; Sabino, Ester C; Coffey, Lark L; Busch, Michael P

    2017-03-01

    Zika virus (ZIKV) has spread rapidly in the Pacific and throughout the Americas and is associated with severe congenital and adult neurologic outcomes. Nucleic acid amplification technology (NAT) assays were developed for diagnostic applications and for blood donor screening on high-throughput NAT systems. We distributed blinded panels to compare the analytical performance of blood screening relative to diagnostic NAT assays. A 25-member, coded panel (11 half-log dilutions of a 2013 French Polynesia ZIKV isolate and 2015 Brazilian donor plasma implicated in transfusion transmission, and 3 negative controls) was sent to 11 laboratories that performed 17 assays with 2 to 12 replicates per panel member. Results were analyzed for the percentage reactivity at each dilution and by probit analysis to estimate the 50% and 95% limits of detection (LOD50 and LOD95 , respectively). Donor-screening NAT assays that process approximately 500 µL of plasma into amplification reactions were comparable in sensitivity (LOD50 and LOD95 , 2.5 and 15-18 copies/mL) and were approximately 10-fold to 100-fold more sensitive than research laboratory-developed and diagnostic reverse transcriptase-polymerase chain reaction tests that process from 10 to 30 µL of plasma per amplification. Increasing sample input volume assayed with the Centers for Disease Control and Prevention reverse transcriptase-polymerase chain reaction assays increased the LODs by 10-fold to 30-fold. Blood donor-screening ZIKV NAT assays demonstrate similar excellent sensitivities to assays currently used for screening for transfusion-transmitted viruses and are substantially more sensitive than most other laboratory-developed and diagnostic ZIKV reverse transcriptase-polymerase chain reaction assays. Enhancing sensitivities of laboratory-developed and diagnostic assays may be achievable by increasing sample input. © 2017 AABB.

  1. Development of a new microparticle-enhanced turbidimetric assay for C-reactive protein with superior features in analytical sensitivity and dynamic range.

    Science.gov (United States)

    Eda, S; Kaufmann, J; Roos, W; Pohl, S

    1998-01-01

    Novel assay techniques were applied to a newly developed microparticle-based assay for C-reactive protein (CRP). By using two different sized microparticles covalently coated with two monoclonal antibodies of different reactivity, high analytical sensitivity and a high upper measuring limit could be simultaneously attained, resulting in a remarkably wide dynamic range. This range was further increased by calculating the signal (reaction rate) optimally with a new software capability of COBAS INTEGRA, a clinical chemistry analyzer. The assay showed high precision between 2 mg/l and 160 mg/l with use of only 2.5 microl specimen. The detection limit was estimated as 0.3 mg/l CRP. The assay was four to eight times more sensitive and precise than existing turbidimetric or nephelometric assays with comparable upper measuring limits. The assay also showed good linearity and correlated well with commercial assays. This new microparticle-based CRP assay provides the accuracy and precision that are required to determine CRP at low concentrations where new clinical implications such as prognosis of cardiovascular diseases are envisaged. The assay's wide dynamic range will additionally lead to a reduction in the number of repeated analyses, thus improving the efficiency of CRP determinations in clinical laboratories.

  2. High quality factor and high sensitivity chalcogenide 1D photonic crystal microbridge cavity for mid-infrared sensing

    Science.gov (United States)

    Xu, Peipeng; Yu, Zenghui; Shen, Xiang; Dai, Shixun

    2017-01-01

    We present and theoretically investigate a mid-infrared (mid-IR) optical sensor based on a Ge11.5As24Se64.5 one-dimensional photonic crystal microbridge cavity (PhC-MC). Optimizing the structure of the PhC-MC strongly confines the resonant mode field to the air region, thereby greatly enhancing the overlap and interaction of the light field and target analytes. A high calculated sensitivity (2280 nm per refractive index unit) is achieved with a resonant wavelength of 4132 nm. The figure of merit of the device for sensing is extremely high (929,750) because of the high quality factor and sensitivity of the cavity. The sensing part of the cavity is also small (50×3 μm2). The proposed PhC-MC can be an ideal platform for on-chip integrated mid-IR optical sensing.

  3. Transplantation in highly HLA-sensitized patients: challenges and solutions

    Directory of Open Access Journals (Sweden)

    Kim IK

    2014-09-01

    Full Text Available Irene K Kim, Ashley Vo, Stanley C Jordan Transplant Immunotherapy Program, Comprehensive Transplant Center, Cedars-Sinai Medical Center, Los Angeles, CA, USA Abstract: Despite better understanding of the impact of development of the human leukocyte antigen (HLA antibody and numerous advancements in immunosuppressive therapy, the ability to successfully transplant highly sensitized patients remains a significant challenge. As the percentage of the waiting list becomes increasingly populated with highly sensitized patients, there is a growing demand for effective strategies to manage these patients. Over the past 20 years, desensitization therapies have been modified and developed, and are mainly utilized at transplant centers that have developed expertise. In addition, recognition that the highly sensitized patient population is disadvantaged on the transplant waiting list has led to recent changes in national kidney allocation policy. Furthermore, creative strategies, such as enrollment of sensitized patients into paired kidney exchange programs, have been developed to find compatible matches for these patients. The goal of this article is to address some of the specific challenges related to transplanting the highly sensitized patient at a high-volume transplant center with experience in desensitization and to review established and emerging solutions to help this patient population. Keywords: human leukocyte antigen, antibodies, desensitization, high-dose intravenous immunoglobulin, rituximab

  4. Mutagen sensitivity has high heritability: evidence from a twin study.

    Science.gov (United States)

    Wu, Xifeng; Spitz, Margaret R; Amos, Christopher I; Lin, Jie; Shao, Lina; Gu, Jian; de Andrade, Mariza; Benowitz, Neal L; Shields, Peter G; Swan, Gary E

    2006-06-15

    Despite numerous studies showing that mutagen sensitivity is a cancer predisposition factor, the heritability of mutagen sensitivity has not been clearly established. In this report, we used a classic twin study design to examine the role of genetic and environmental factors on the mutagen sensitivity phenotype. Mutagen sensitivity was measured in peripheral blood lymphocytes from 460 individuals [148 pairs of monozygotic (MZ) twins, 57 pairs of dizygotic (DZ) twins, and 50 siblings]. The intraclass correlation coefficients were all significantly higher in MZ twins than in dizygotes (DZ pairs and MZ-sibling pairs combined) for sensitivity to four different mutagen challenges. Applying biometric genetic modeling, we calculated a genetic heritability of 40.7%, 48.0%, 62.5%, and 58.8% for bleomycin, benzo[a]pyrene diol epoxide, gamma-radiation, and 4-nitroquinoline-1-oxide sensitivity, respectively. This study provides the strongest and most direct evidence that mutagen sensitivity is highly heritable, thereby validating the use of mutagen sensitivity as a cancer susceptibility factor.

  5. Highly sensitive detection of cancer cells with an electrochemical cytosensor based on boronic acid functional polythiophene.

    Science.gov (United States)

    Dervisevic, Muamer; Senel, Mehmet; Sagir, Tugba; Isik, Sevim

    2017-04-15

    The detection of cancer cells through important molecular recognition target such as sialic acid is significant for the clinical diagnosis and treatment. There are many electrochemical cytosensors developed for cancer cells detection but most of them have complicated fabrication processes which results in poor reproducibility and reliability. In this study, a simple, low-cost, and highly sensitive electrochemical cytosensor was designed based on boronic acid-functionalized polythiophene. In cytosensors fabrication simple single-step procedure was used which includes coating pencil graphite electrode (PGE) by means of electro-polymerization of 3-Thienyl boronic acid and Thiophen. Electrochemical impedance spectroscopy and cyclic voltammetry were used as an analytical methods to optimize and measure analytical performances of PGE/P(TBA0.5Th0.5) based electrode. Cytosensor showed extremely good analytical performances in detection of cancer cells with linear rage of 1×10(1) to 1×10(6) cellsmL(-1) exhibiting low detection limit of 10 cellsmL(-1) and incubation time of 10min. Next to excellent analytical performances, it showed high selectivity towards AGS cancer cells when compared to HEK 293 normal cells and bone marrow mesenchymal stem cells (BM-hMSCs). This method is promising for future applications in early stage cancer diagnosis.

  6. Achieving sensitive, high-resolution laser spectroscopy at CRIS

    Energy Technology Data Exchange (ETDEWEB)

    Groote, R. P. de [Instituut voor Kern- en Stralingsfysica, KU Leuven (Belgium); Lynch, K. M., E-mail: kara.marie.lynch@cern.ch [EP Department, CERN, ISOLDE (Switzerland); Wilkins, S. G. [The University of Manchester, School of Physics and Astronomy (United Kingdom); Collaboration: the CRIS collaboration

    2017-11-15

    The Collinear Resonance Ionization Spectroscopy (CRIS) experiment, located at the ISOLDE facility, has recently performed high-resolution laser spectroscopy, with linewidths down to 20 MHz. In this article, we present the modifications to the beam line and the newly-installed laser systems that have made sensitive, high-resolution measurements possible. Highlights of recent experimental campaigns are presented.

  7. A highly sensitive optical detector for use in deep underwater.

    Science.gov (United States)

    Hanada, H.; Hayashino, T.; Ito, M.; Iwasaki, A.; Kawamorita, K.; Kawamoto, H.; Matsumoto, T.; Narita, S.; Takayama, T.; Tanaka, S.; Yamaguchi, A.; Aoki, T.; Mitsui, K.; Ohashi, Y.; Okada, A.; Fukawa, M.; Uehara, S.; Bolesta, J. W.; Gorham, P. W.; Kondo, S.; Learned, J. G.; Matsuno, S.; Mignard, M.; Mitiguy, R.; O'Connor, D. J.; Peterson, V. Z.; Roberts, A.; Rosen, M.; Stenger, V. J.; Takemori, D.; Wilkins, G.; Grieder, P. K. F.; Minkowski, P.; Kitamura, T.; Camerini, U.; Grogan, W.; Jaworski, M.; March, R.; Narita, T.; Nicklaus, D.

    1998-05-01

    The authors have developed an optical detector module for use in deep underwater experiments that will search for high-energy neutrinos from cosmic rays and astronomical sources. This module is sensitive to single photons, is operable under high pressure, functions automatically and is remotely controlled.

  8. Optical Microbubble Resonators with High Refractive Index Inner Coating for Bio-Sensing Applications: An Analytical Approach

    Directory of Open Access Journals (Sweden)

    Andrea Barucci

    2016-11-01

    Full Text Available The design of Whispering Gallery Mode Resonators (WGMRs used as an optical transducer for biosensing represents the first and crucial step towards the optimization of the final device performance in terms of sensitivity and Limit of Detection (LoD. Here, we propose an analytical method for the design of an optical microbubble resonator (OMBR-based biosensor. In order to enhance the OMBR sensing performance, we consider a polymeric layer of high refractive index as an inner coating for the OMBR. The effect of this layer and other optical/geometrical parameters on the mode field distribution, sensitivity and LoD of the OMBR is assessed and discussed, both for transverse electric (TE and transverse magnetic (TM polarization. The obtained results do provide physical insights for the development of OMBR-based biosensor.

  9. Optical Microbubble Resonators with High Refractive Index Inner Coating for Bio-Sensing Applications: An Analytical Approach

    Science.gov (United States)

    Barucci, Andrea; Berneschi, Simone; Giannetti, Ambra; Baldini, Francesco; Cosci, Alessandro; Pelli, Stefano; Farnesi, Daniele; Righini, Giancarlo C.; Soria, Silvia; Nunzi Conti, Gualtiero

    2016-01-01

    The design of Whispering Gallery Mode Resonators (WGMRs) used as an optical transducer for biosensing represents the first and crucial step towards the optimization of the final device performance in terms of sensitivity and Limit of Detection (LoD). Here, we propose an analytical method for the design of an optical microbubble resonator (OMBR)-based biosensor. In order to enhance the OMBR sensing performance, we consider a polymeric layer of high refractive index as an inner coating for the OMBR. The effect of this layer and other optical/geometrical parameters on the mode field distribution, sensitivity and LoD of the OMBR is assessed and discussed, both for transverse electric (TE) and transverse magnetic (TM) polarization. The obtained results do provide physical insights for the development of OMBR-based biosensor. PMID:27898015

  10. Analytical protocol for the sensitive determination of mannitol, sorbitol and glucose containing powders in pharmaceutical workplaces by ion chromatography using a pulsed amperometric detector.

    Science.gov (United States)

    Butler, Owen; Forder, James; Saunders, John

    2015-03-15

    Workers in the pharmaceutical industry can potentially be exposed to airborne dusts and powders that can contain potent active pharmaceutical ingredients (API). Occupational hygienists and health and safety professionals need to assess and ultimately minimise such inhalation and dermal exposure risks. Containment of dusts at source is the first line of defence but the performance of such technologies needs to be verified, for which purpose the good practice guide: assessing the particulate containment performance of pharmaceutical equipment, produced by the International Society for Pharmaceutical Engineering (ISPE), is a widely used reference document. This guide recommends the use of surrogate powders that can be used to challenge the performance of such containment systems. Materials such as lactose and mannitol are recommended as their physical properties (adhesion, compactability, dustiness, flow characteristics and particle sizes) mimic those of API-containing materials typically handled. Furthermore they are safe materials to use, are available in high purity and can be procured at a reasonable cost. The aim of this work was to develop and validate a sensitive ion-chromatography based analytical procedure for the determination of surrogate powders collected on filter samples so as to meet analytical requirements set out in this ISPE guide.

  11. Notch Sensitivity of Woven Ceramic Matrix Composites Under Tensile Loading: An Experimental, Analytical, and Finite Element Study

    Science.gov (United States)

    Haque, A.; Ahmed, L.; Ware, T.; Jeelani, S.; Verrilli, Michael J. (Technical Monitor)

    2001-01-01

    The stress concentrations associated with circular notches and subjected to uniform tensile loading in woven ceramic matrix composites (CMCs) have been investigated for high-efficient turbine engine applications. The CMC's were composed of Nicalon silicon carbide woven fabric in SiNC matrix manufactured through polymer impregnation process (PIP). Several combinations of hole diameter/plate width ratios and ply orientations were considered in this study. In the first part, the stress concentrations were calculated measuring strain distributions surrounding the hole using strain gages at different locations of the specimens during the initial portion of the stress-strain curve before any microdamage developed. The stress concentration was also calculated analytically using Lekhnitskii's solution for orthotropic plates. A finite-width correction factor for anisotropic and orthotropic composite plate was considered. The stress distributions surrounding the circular hole of a CMC's plate were further studied using finite element analysis. Both solid and shell elements were considered. The experimental results were compared with both the analytical and finite element solutions. Extensive optical and scanning electron microscopic examinations were carried out for identifying the fracture behavior and failure mechanisms of both the notched and notched specimens. The stress concentration factors (SCF) determined by analytical method overpredicted the experimental results. But the numerical solution underpredicted the experimental SCF. Stress concentration factors are shown to increase with enlarged hole size and the effects of ply orientations on stress concentration factors are observed to be negligible. In all the cases, the crack initiated at the notch edge and propagated along the width towards the edge of the specimens.

  12. Nuclear techniques in analytical chemistry

    CERN Document Server

    Moses, Alfred J; Gordon, L

    1964-01-01

    Nuclear Techniques in Analytical Chemistry discusses highly sensitive nuclear techniques that determine the micro- and macro-amounts or trace elements of materials. With the increasingly frequent demand for the chemical determination of trace amounts of elements in materials, the analytical chemist had to search for more sensitive methods of analysis. This book accustoms analytical chemists with nuclear techniques that possess the desired sensitivity and applicability at trace levels. The topics covered include safe handling of radioactivity; measurement of natural radioactivity; and neutron a

  13. High sensitivity to punishment and low impulsivity in obsessive-compulsive patients with hoarding symptoms.

    Science.gov (United States)

    Fullana, Miquel Angel; Mataix-Cols, David; Caseras, Xavier; Alonso, Pino; Manuel Menchón, Josep; Vallejo, Julio; Torrubia, Rafael

    2004-11-30

    Recent factor-analytic studies involving over 2000 patients have reduced the symptoms of obsessive-compulsive disorder (OCD) into a few dimensions or potentially overlapping syndromes. Hoarding consistently emerged as a separate factor in all these studies. This study investigated the relationship between OCD symptom dimensions and normal personality traits in a sample of 56 OCD patients. They were administered the Sensitivity to Punishment and Sensitivity to Reward Questionnaire and the Eysenck Personality Questionnaire, derived from Gray's and Eysenck's personality models, respectively. The personality scores were correlated with previously identified symptom dimensions from the Yale-Brown Obsessive-Compulsive Scale Symptom Checklist (Y-BOCS-SC), controlling for overall illness severity. High scores on the hoarding dimension of the Y-BOCS-SC were positively correlated with scores on the Sensitivity to Punishment scale and negatively with Eysenck's Psychoticism scale. While high sensitivity to punishment is a personality feature common to many OCD patients, it is more strongly pronounced in patients with hoarding symptoms. These patients also appear to be less impulsive or novelty seeking as reflected by low scores on Eysenck's Psychoticism scale. High sensitivity to punishment and low novelty seeking in OCD hoarders might explain their poor compliance and response to conventional treatments, but this question needs to be explored further in a prospective treatment study.

  14. Research of High Sensitivity Uncooled Infrared Detector Array

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Pingchuan [Huazhong University of Science and Technology, Wuhan 430074 (China); Zhang, Bo, E-mail: redmoon123456@126.com, E-mail: lhzyzb@126.com [Luohe Vocational Technology College, Luohe 462002 (China)

    2011-02-01

    The infrared thermal imaging technology has been widely used in military and civilian fields and the field of the infrared detection and infrared thermal imaging technology has been of concern for a long time. On infrared thermal imaging, its core components for the infrared focal plane arrays, how to develop a high sensitivity of the multi-focal plane infrared detector is a key issue. Although the Common focal plane array of quantum has high sensitivity, but it requires low temperature cooling work environment and led to complexity and high cost, difficult to compact. Conventional uncooled infrared focal plane array is contrast to the quantum focal plane arrays. Therefore, this article preceded by the uncooled infrared detector array to improve the wide temperature sensitivity in examining the feasibility PMN composite film, materials composition, structure design and preparation process technology.

  15. Establishment of chondroitin B lyase-based analytical methods for sensitive and quantitative detection of dermatan sulfate in heparin.

    Science.gov (United States)

    Wu, Jingjun; Ji, Yang; Su, Nan; Li, Ye; Liu, Xinxin; Mei, Xiang; Zhou, Qianqian; Zhang, Chong; Xing, Xin-hui

    2016-06-25

    Dermatan sulfate (DS) is one of the hardest impurities to remove from heparin products due to their high structural similarity. The development of a sensitive and feasible method for quantitative detection of DS in heparin is essential to ensure the clinical safety of heparin pharmaceuticals. In the current study, based on the substrate specificity of chondroitin B lyase, ultraviolet spectrophotometric and strong anion-exchange high-performance liquid chromatographic methods were established for detection of DS in heparin. The former method facilitated analysis in heparin with DS concentrations greater than 0.1mgmL(-1) at 232nm, with good linearity, precision and recovery. The latter method allowed sensitive and accurate detection of DS at concentrations lower than 0.1mgmL(-1), exhibiting good linearity, precision and recovery. The linear range of DS detection using the latter method was between 0.01 and 0.5mgmL(-1).

  16. Highly sensitive optical sensor system for blood leakage detection

    Science.gov (United States)

    Ueda, Masahiro; Ishikawa, Kazuhiko; Jie, Chen; Sanae, Mizuno; Touma, Yasunori

    A highly sensitive method for the detection of blood leakage has been developed, and a practical sensor system for blood concentration measurement has been constructed. The present method is based on the attenuation of laser light by blood cells. The effects of the fluctuations of the incident laser light power are eliminated by normalizing the attenuated light intensity by the incident light intensity. A part of the incident laser light is reflected by a beam splitter mounted at the entrance of the test cell, of which the power is measured to provide base data for normalization. The optical path is extended to enhance sensitivity by using a pair of side mirrors. This multi-reflection method is very effective to increase sensitivity; the maximum sensitivity obtained for blood concentration is about 4 X 10 -6 by volume, which is significantly higher than that of the conventional sensors.

  17. Dynamic performance of frictionless fast shutters for ITER: Numerical and analytical sensitivity study for the development of a test program

    Energy Technology Data Exchange (ETDEWEB)

    Panin, Anatoly, E-mail: a.panin@fz-juelich.de [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, 52425 Jülich (Germany); Khovayko, Mikhail [St. Petersburg Polytechnic University, Mechanics and Control Processes Department, Computational Mechanics Laboratory, 195251 St. Petersburg (Russian Federation); Krasikov, Yury [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, 52425 Jülich (Germany); Nemov, Alexander [St. Petersburg Polytechnic University, Mechanics and Control Processes Department, Computational Mechanics Laboratory, 195251 St. Petersburg (Russian Federation); Biel, Wolfgang; Mertens, Philippe; Neubauer, Olaf; Schrader, Michael [Forschungszentrum Jülich GmbH, Institut für Energie- und Klimaforschung – Plasmaphysik, 52425 Jülich (Germany)

    2015-10-15

    To prolong a lifetime of the ITER first diagnostic mirrors some protective shutters can be engaged. A concept of an elastic shutter that operates frictionless in vacuum has been studied at the Forschungszentrum Jülich, Germany. Under actuation two shutter arms (∼2 m long) bend laterally between two pairs of limiting bumpers thus shielding the optical aperture or opening it for measurements. To increase the shutter efficiency the transition time between its open and closed states can be minimized. This demands a fast shutter that operates in fractions of a second and exhibit essentially dynamic behavior, like impacts with the bumpers that cause the shutter arms’ bouncing and oscillations. The paper presents numerical studies of the shutter dynamic behavior using the explicit and implicit 3D FE transient structural modeling. Simple 1D analytical model was developed to predict the shutter impact kinetic energy that mostly determines its further dynamic response. The structure sensitivity to different parameters was studied and ways for its optimization were laid down. A parametric shutter mockup with easily changeable mechanical characteristics was manufactured. A test program aimed for further shutter optimization, basing on the analysis performed and engaging powerful capabilities of the parametric shutter mockup is discussed in the paper.

  18. Scalable photonic crystal chips for high sensitivity protein detection.

    Science.gov (United States)

    Liang, Feng; Clarke, Nigel; Patel, Parth; Loncar, Marko; Quan, Qimin

    2013-12-30

    Scalable microfabrication technology has enabled semiconductor and microelectronics industries, among other fields. Meanwhile, rapid and sensitive bio-molecule detection is increasingly important for drug discovery and biomedical diagnostics. In this work, we designed and demonstrated that photonic crystal sensor chips have high sensitivity for protein detection and can be mass-produced with scalable deep-UV lithography. We demonstrated label-free detection of carcinoembryonic antigen from pg/mL to μg/mL, with high quality factor photonic crystal nanobeam cavities.

  19. Experimental Investigation on a Highly Sensitive Atomic Magnetometer

    Institute of Scientific and Technical Information of China (English)

    LI Shu-Guang; XU Yun-Fei; WANG Zhao-Ying; LIU Yun-Xian; LIN Qiang

    2009-01-01

    A highly sensitive all-optical atomic magnetometer based on the magnetooptical effect which uses the advanced technique of single laser beam detection is reported and demonstrated experimentally.A sensitivityof 0.5 pT/Hz1/2 is obtained by analyzing the magnetic noise spectrum,which exceeds that of most traditional magnetometers.This kind of atomic magnetometer is very compact,has a low power consumption,and has a high theoretical sensitivity limit,which make it suitable for many applications.

  20. Photo- and biophysical studies of lectin-conjugated fluorescent nanoparticles: reduced sensitivity in high density assays.

    Science.gov (United States)

    Wang, Yaqi; Gildersleeve, Jeffrey C; Basu, Amit; Zimmt, Matthew B

    2010-11-18

    Lectin-conjugated, fluorescent silica nanoparticles (fNP) have been developed for carbohydrate-based histopathology evaluations of epithelial tissue biopsies. The fNP platform was selected for its enhanced emissive brightness compared to direct dye labeling. Carbohydrate microarray studies were performed to compare the carbohydrate selectivity of the mannose-recognizing lectin Concanavalin A (ConA) before and after conjugation to fluorescent silica nanoparticles (ConA-fNP). These studies revealed surprisingly low emission intensities upon staining with ConA-fNP compared to those with biotin-ConA/Cy3-streptavidin staining. A series of photophysical and biophysical characterizations of the fNP and ConA-fNP conjugates were performed to probe the low sensitivity from fNP in the microarray assays. Up to 1200 fluorescein (FL) and 80 tetramethylrhodamine (TR) dye molecules were incorporated into 46 nm diameter fNP, yielding emissive brightness values 400 and 35 times larger than the individual dye molecules, respectively. ConA lectin conjugated to carboxylic acid surface-modified nanoparticles covers 15-30% of the fNP surface. The CD spectra and mannose substrate selectivity of ConA conjugated to the fNP differed slightly compared to that of soluble ConA. Although, the high emissive brightness of fNP enhances detection sensitivity for samples with low analyte densities, large fNP diameters limit fNP recruitment and binding to samples with high analyte densities. The high analyte density and nearly two-dimensional target format of carbohydrate microarrays make probe size a critical parameter. In this application, fNP labels afford minimal sensitivity advantage compared to direct dye labeling.

  1. Molecular structure and thermodynamic predictions to create highly sensitive microRNA biosensors

    Energy Technology Data Exchange (ETDEWEB)

    Larkey, Nicholas E.; Brucks, Corinne N.; Lansing, Shan S.; Le, Sophia D.; Smith, Natasha M.; Tran, Victoria; Zhang, Lulu; Burrows, Sean M., E-mail: sean.burrows@oregonstate.edu

    2016-02-25

    Many studies have established microRNAs (miRNAs) as post-transcriptional regulators in a variety of intracellular molecular processes. Abnormal changes in miRNA have been associated with several diseases. However, these changes are sometimes subtle and occur at nanomolar levels or lower. Several biosensing hurdles for in situ cellular/tissue analysis of miRNA limit detection of small amounts of miRNA. Of these limitations the most challenging are selectivity and sensor degradation creating high background signals and false signals. Recently we developed a reporter+probe biosensor for let-7a that showed potential to mitigate false signal from sensor degradation. Here we designed reporter+probe biosensors for miR-26a-2-3p and miR-27a-5p to better understand the effect of thermodynamics and molecular structures of the biosensor constituents on the analytical performance. Signal changes from interactions between Cy3 and Cy5 on the reporters were used to understand structural aspects of the reporter designs. Theoretical thermodynamic values, single stranded conformations, hetero- and homodimerization structures, and equilibrium concentrations of the reporters and probes were used to interpret the experimental observations. Studies of the sensitivity and selectivity revealed 5–9 nM detection limits in the presence and absence of interfering off-analyte miRNAs. These studies will aid in determining how to rationally design reporter+probe biosensors to overcome hurdles associated with highly sensitive miRNA biosensing. - Highlights: • Challenges facing highly sensitive miRNA biosensor designs are addressed. • Thermodynamic and molecular structure design metrics for reporter+probe biosensors are proposed. • The influence of ideal and non-ideal reporter hairpin structures on reporter+probe formation and signal change are discussed. • 5–9 nM limits of detection were observed with no interference from off-analytes.

  2. High-sensitivity, high-speed continuous imaging system

    Science.gov (United States)

    Watson, Scott A; Bender, III, Howard A

    2014-11-18

    A continuous imaging system for recording low levels of light typically extending over small distances with high-frame rates and with a large number of frames is described. Photodiode pixels disposed in an array having a chosen geometry, each pixel having a dedicated amplifier, analog-to-digital convertor, and memory, provide parallel operation of the system. When combined with a plurality of scintillators responsive to a selected source of radiation, in a scintillator array, the light from each scintillator being directed to a single corresponding photodiode in close proximity or lens-coupled thereto, embodiments of the present imaging system may provide images of x-ray, gamma ray, proton, and neutron sources with high efficiency.

  3. Large pi-aromatic molecules as potential sensitizers for highly efficient dye-sensitized solar cells.

    Science.gov (United States)

    Imahori, Hiroshi; Umeyama, Tomokazu; Ito, Seigo

    2009-11-17

    Recently, dye-sensitized solar cells have attracted much attention relevant to global environmental issues. Thus far, ruthenium(II) bipyridyl complexes have proven to be the most efficient TiO(2) sensitizers in dye-sensitized solar cells. However, a gradual increment in the highest power conversion efficiency has been recognized in the past decade. More importantly, considering that ruthenium is a rare metal, novel dyes without metal or using inexpensive metal are desirable for highly efficient dye-sensitized solar cells. Large pi-aromatic molecules, such as porphyrins, phthalocyanines, and perylenes, are important classes of potential sensitizers for highly efficient dye-sensitized solar cells, owing to their photostability and high light-harvesting capabilities that can allow applications in thinner, low-cost dye-sensitized solar cells. Porphyrins possess an intense Soret band at 400 nm and moderate Q bands at 600 nm. Nevertheless, the poor light-harvesting properties relative to the ruthenium complexes have limited the cell performance of porphyrin-sensitized TiO(2) cells. Elongation of the pi conjugation and loss of symmetry in porphyrins cause broadening and a red shift of the absorption bands together with an increasing intensity of the Q bands relative to that of the Soret band. On the basis of the strategy, the cell performance of porphyrin-sensitized solar cells has been improved intensively by the enhanced light absorption. Actually, some push-pull-type porphyrins have disclosed a remarkably high power conversion efficiency (6-7%) that was close to that of the ruthenium complexes. Phthalocyanines exhibit strong absorption around 300 and 700 nm and redox features that are similar to porphyrins. Moreover, phthalocyanines are transparent over a large region of the visible spectrum, thereby enabling the possibility of using them as "photovoltaic windows". However, the cell performance was poor, owing to strong aggregation and lack of directionality in the

  4. Portable High Sensitivity and High Resolution Sensor to Determine Oxygen Purity Levels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I STTR project is to develop a highly sensitive oxygen (O2) sensor, with high accuracy and precision, to determine purity levels of high...

  5. A Two-Dimensional Analytic Thermal Model for a High-Speed PMSM Magnet

    CSIR Research Space (South Africa)

    Grobler, AJ

    2015-11-01

    Full Text Available TRANSACTIONS ON INDUSTRIAL ELECTRONICS, VOL. 62, NO. 11, NOVEMBER 2015 A Two-Dimensional Analytic Thermal Model for a High-Speed PMSM Magnet Andries J. Groblera, Stanley Robert Holmb, and George van Schoorc a School of Electrical, Electronic...

  6. Analytical Study of High Concentration PCB Paint at the Heavy Water Components Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Lowry, N.J.

    1998-10-21

    This report provides results of an analytical study of high concentration PCB paint in a shutdown nuclear test reactor located at the US Department of Energy's Savannah River Site (SRS). The study was designed to obtain data relevant for an evaluation of potential hazards associated with the use of and exposure to such paints.

  7. Aluminum nano-cantilevers for high sensitivity mass sensors

    DEFF Research Database (Denmark)

    Davis, Zachary James; Boisen, Anja

    2005-01-01

    We have fabricated Al nano-cantilevers using a very simple one mask contact UV lithography technique with lateral dimensions under 500 nm and vertical dimensions of approximately 100 nm. These devices are demonstrated as highly sensitive mass sensors by measuring their dynamic properties. Further...

  8. Highly Sensitive AMS Measurement of 53Mn at CIAE

    Institute of Scientific and Technical Information of China (English)

    DONG; Ke-jun; HU; Hao; LIU; Guang-shan; HE; Ming; LI; Zhen-yu; DOU; Liang; XIE; Lin-bo; LIU; Jian-cheng; WANG; Xiang-gao; SHEN; Hong-tao; LIN; De-yu; ZHENG; Guo-wen; WANG; Xiao-bo; LI; Heng; LI; Chao-li; WU; Shao-yong; YOU; Qu-bo; JIN; Chun-sheng; CHEN; Zhi-gang; YUAN; Jian; JIANG; Shan

    2013-01-01

    Methods for highly sensitive AMS measurement of 53Mn were explored by extracting different Mn-containing molecular ions in ion source and using different chemical forms of sample materials.Preliminary results indicate that a method for AMS measurement of 53Mn has been established and a-155355

  9. Sensitivity Study of Strapdown Inertial Sensors in High Performance Applications

    Science.gov (United States)

    1980-12-01

    system error varied with a change in heading 7K. ( xii 1 SENSITIVITY STUDY OF STRAPDOWN INERTIAL SENSORS IN HIGH PERFORMANCE APPLICATIONS I. Introduction...given in Tabla 10. 23 State Meaning o Basic Altitude Damped INS x(1) Error in East Longitude 5.7735 x 1O Ŗ arc min x(2) Error in North Latitude

  10. [Burner head with high sensitivity in atomic absorption spectroscopy].

    Science.gov (United States)

    Feng, X; Yang, Y

    1998-12-01

    This paper presents a burner head with gas-sample separate entrance and double access, which is used for atomic absorption spectroscopy. According to comparison and detection, the device can improve sensitivity by a factor of 1 to 5. In the meantime it has properties of high stability and resistance to interference.

  11. Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

    Science.gov (United States)

    Zhang, Jing; Su, Yan; Shi, Qin; Qiu, An-Ping

    2015-01-01

    This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA). This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF) resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI) processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ) of 48 μg and the bias-instability of 4.8 μg have been achieved. PMID:26633425

  12. Microelectromechanical Resonant Accelerometer Designed with a High Sensitivity

    Directory of Open Access Journals (Sweden)

    Jing Zhang

    2015-12-01

    Full Text Available This paper describes the design and experimental evaluation of a silicon micro-machined resonant accelerometer (SMRA. This type of accelerometer works on the principle that a proof mass under acceleration applies force to two double-ended tuning fork (DETF resonators, and the frequency output of two DETFs exhibits a differential shift. The dies of an SMRA are fabricated using silicon-on-insulator (SOI processing and wafer-level vacuum packaging. This research aims to design a high-sensitivity SMRA because a high sensitivity allows for the acceleration signal to be easily demodulated by frequency counting techniques and decreases the noise level. This study applies the energy-consumed concept and the Nelder-Mead algorithm in the SMRA to address the design issues and further increase its sensitivity. Using this novel method, the sensitivity of the SMRA has been increased by 66.1%, which attributes to both the re-designed DETF and the reduced energy loss on the micro-lever. The results of both the closed-form and finite-element analyses are described and are in agreement with one another. A resonant frequency of approximately 22 kHz, a frequency sensitivity of over 250 Hz per g, a one-hour bias stability of 55 μg, a bias repeatability (1σ of 48 μg and the bias-instability of 4.8 μg have been achieved.

  13. Sensitive Method for Enantioseparation of Rivastigmine with Highly Sulfated Cyclodextrin as Chiral Selector by Capillary Electrophoresis

    Institute of Scientific and Technical Information of China (English)

    WANG Zhao-Yan; XU Xing-Xiang; HU Zhi-De; KANG Jing-Wu

    2006-01-01

    A sensitive method for enantioseparation of a basic drug rivastigmine and determination of its optical impurity by capillary electrophoresis with highly sulfatedβ-cyclodextrin (HS-β-CD) as the chiral selector is described. In general, enantioseparation of basic chiral compounds is carried out in acidic condition (pH 2.5) to prevent analytes from adsorption on the capillary wall. However, in the case of rivastigmine, the detection sensitivity was too limited to determine the optical impurity of S-rivastigmine lower than 1% when buffer pH was 2.5. It was found that the detection sensitivity was improved 1.6 times just by raising the buffer pH value from 2.5 to 5.8. The poor column efficiency due to the adsorption of the analytes on the capillary wall was resolved by using dynamical coating of the capillary wall with the linear polyacrylamide solution. The experimental parameters such as the concentration of HS-β-CD, buffer pH and buffer ionic strength were optimized, respectively. The method was validated in terms of repeatability, linearity, limit of detection (LOD) and limit of quantitation (LOQ). Using the present method, the optical purity of nonracemic rivastigmine with the enantiomeric excess (ee) value of 99.14% was determined.

  14. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR)

    Science.gov (United States)

    Arapan, Lilia; Alexieva, Gergana; Avramov, Ivan D.; Radeva, Ekaterina; Strashilov, Vesseline; Katardjiev, Ilia; Yantchev, Ventsislav

    2011-01-01

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented. PMID:22163994

  15. Highly mass-sensitive thin film plate acoustic resonators (FPAR).

    Science.gov (United States)

    Arapan, Lilia; Alexieva, Gergana; Avramov, Ivan D; Radeva, Ekaterina; Strashilov, Vesseline; Katardjiev, Ilia; Yantchev, Ventsislav

    2011-01-01

    The mass sensitivity of thin aluminum nitride (AlN) film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO)-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

  16. Design and Fabrication of High Sensitive Piezoresistive MEMS Accelerometer

    Directory of Open Access Journals (Sweden)

    JOSHI A.B

    2008-04-01

    Full Text Available This paper addresses the design and fabrication of high sensitive single axis piezoresistive micro-accelerometer for 50 g application. MEMS based accelerometer structure comprise of flexure fixed at one end and having attached proof mass at other end. This structure is designed and simulated using Coventorware. The simulation results show the sensitivity of 4mV/g. The structure is fabricated in N type silicon (100 substrate using Silicon bulk micromachining. This paper also discuses the use of PECVD Si3N4 layer as a masking material for silicon micromachining and process flow for accelerometer.

  17. Cardiac troponins and high-sensitivity cardiac troponin assays.

    Science.gov (United States)

    Conrad, Michael J; Jarolim, Petr

    2014-03-01

    Measurement of circulating cardiac troponins I and T has become integral to the diagnosis of myocardial infarction. This article discusses the structure and function of the troponin complex and the release of cardiac troponin molecules from the injured cardiomyocyte into the circulation. An overview of current cardiac troponin assays and their classification according to sensitivity is presented. The diagnostic criteria, role, and usefulness of cardiac troponin for myocardial infarction are discussed. In addition, several examples are given of the usefulness of high-sensitivity cardiac troponin assays for short-term and long-term prediction of adverse events.

  18. Highly Mass-Sensitive Thin Film Plate Acoustic Resonators (FPAR

    Directory of Open Access Journals (Sweden)

    Ventsislav Yantchev

    2011-07-01

    Full Text Available The mass sensitivity of thin aluminum nitride (AlN film S0 Lamb wave resonators is theoretically and experimentally studied. Theoretical predictions based on modal and finite elements method analysis are experimentally verified. Here, two-port 888 MHz synchronous FPARs are micromachined and subsequently coated with hexamethyl-disiloxane(HMDSO-plasma-polymerized thin films of various thicknesses. Systematic data on frequency shift and insertion loss versus film thickness are presented. FPARs demonstrate high mass-loading sensitivity as well as good tolerance towards the HMDSO viscous losses. Initial measurements in gas phase environment are further presented.

  19. High Sensitivity Very Low Frequency Receiver for Earthquake Data Acquisition.

    Science.gov (United States)

    Munir, A.; Najmurrokhman, A.

    2017-03-01

    high sensitivity very low frequency (VLF) receiver is developed based on AD744 monolithic operational amplifier (Op-Amp) for earthquake data acquisition. In research related natural phenomena such as atmospheric noise, lightning and earthquake, a VLF receiver particularly with high sensitivity is utterly required due to the low power of VLF wave signals received by the antenna. The developed receiver is intended to have high sensitivity reception for the signals in frequency range of 10-30kHz allocated for earthquake observation. The VLF receiver which is portably designed is also equipped with an output port connectable to the soundcard of personal computer for further data acquisition. After obtaining the optimum design, the hardware realization is implemented on a printed circuit board (PCB) for experimental characterization. It shows that the sensitivity of realized VLF receiver is almost linear in the predefined frequency range for the input signals lower than -12dBm and to be quadratic for the higher level input signals.

  20. Sensitive method for detection of cocaine and associated analytes by liquid chromatography-tandem mass spectrometry in urine.

    Science.gov (United States)

    Langman, Loralie J; Bjergum, Matthew W; Williamson, Christopher L; Crow, Frank W

    2009-10-01

    Cocaine (COC) is a potent CNS stimulant that is metabolized to benzoylecgonine (BE) and further metabolized to minor metabolites such as m-hydroxybenzoylecgonine (m-HOBE). COC is also metabolized to norcocaine (NC). Cocaethylene (CE) is formed when cocaine and ethyl alcohol are used simultaneously. Anhydroecgonine methyl ester (AEME) is a unique marker following smoked cocaine, and anhydroecgonine ethyl ester (AEEE) is found in cocaine smokers who also use ethyl alcohol. We developed a liquid chromatography-tandem mass spectrometry (LC-MS-MS) method for the detection and quantitation of COC, BE, NC, CE, m-HOBE, AEME, and AEEE in urine. Two hundred samples previously analyzed by gas chromatography (GC) coupled with MS were extracted using solid-phase extraction. Chromatographic separation was achieved using a gradient consisting of mobile phase A [20 mM ammonium formate (pH 2.7)] and mobile phase B (methanol/acetonitrile, 50:50), an XDB-C(8) (50 x 2.1 mm, 1.8 microm) column and a flow rate of 270 microL/min. Concentrations were calculated by comparing the peak-area with the internal standard and plotted against a standard curve. The assay displayed linearity from 1.0 to 100 ng/mL. Within- and between-run coefficients of variation were < 10% throughout the linear range. A method comparison between GC-MS and LC-MS-MS showed good correlation for COC (r(2) = 0.982) and BE (r(2) = 0.955). We report here on a sensitive method to identify clinically and forensically relevant cocaine and associated analytes at concentrations as low as 1.0 ng/mL.

  1. High Sensitivity Polymer Optical Fiber-Bragg-Grating-Based Accelerometer

    DEFF Research Database (Denmark)

    Stefani, Alessio; Andresen, Søren; Yuan, Wu

    2012-01-01

    We report on the fabrication and characterization of the first accelerometer based on a polymer optical fiber Bragg grating (FBG) for operation at both 850 and 1550 nm. The devices have a flat frequency response over a 1-kHz bandwidth and a resonance frequency of about 3 kHz. The response is linear...... up to at least 15 g and sensitivities as high as 19 pm/g (shift in resonance wavelength per unit acceleration) have been demonstrated. Given that 15 g corresponds to a strain of less than 0.02% and that polymer fibers have an elastic limit of more than 1%, the polymer FBG accelerometer can measure...... very strong accelerations. We compare with corresponding silica FBG accelerometers and demonstrate that using polymer FBGs improves the sensitivity by more than a factor of four and increases the figure of merit, defined as the sensitivity times the resonance frequency squared....

  2. Are Inflationary Predictions Sensitive to Very High Energy Physics?

    CERN Document Server

    Burgess, C P; Lemieux, F; Holman, R

    2003-01-01

    It has been proposed that the successful inflationary description of density perturbations on cosmological scales is sensitive to the details of physics at extremely high (trans-Planckian) energies. We test this proposal by examining how inflationary predictions depend on higher-energy scales within a simple model where the higher-energy physics is well understood. We find the best of all possible worlds: inflationary predictions are robust against the vast majority of high-energy effects, but can be sensitive to some effects in certain circumstances, in a way which does not violate ordinary notions of decoupling. This implies both that the comparison of inflationary predictions with CMB data is meaningful, and that it is also worth searching for small deviations from the standard results in the hopes of learning about very high energies.

  3. Sensitivity of HAWC to high-mass dark matter annihilations

    Science.gov (United States)

    Abeysekara, A. U.; Alfaro, R.; Alvarez, C.; Álvarez, J. D.; Arceo, R.; Arteaga-Velázquez, J. C.; Ayala Solares, H. A.; Barber, A. S.; Baughman, B. M.; Bautista-Elivar, N.; Becerra Gonzalez, J.; Belmont, E.; BenZvi, S. Y.; Berley, D.; Bonilla Rosales, M.; Braun, J.; Caballero-Lopez, R. A.; Caballero-Mora, K. S.; Carramiñana, A.; Castillo, M.; Cotti, U.; Cotzomi, J.; de la Fuente, E.; De León, C.; DeYoung, T.; Diaz Hernandez, R.; Diaz-Cruz, L.; Díaz-Vélez, J. C.; Dingus, B. L.; DuVernois, M. A.; Ellsworth, R. W.; Fiorino, D. W.; Fraija, N.; Galindo, A.; Garfias, F.; González, M. M.; Goodman, J. A.; Grabski, V.; Gussert, M.; Hampel-Arias, Z.; Harding, J. P.; Hui, C. M.; Hüntemeyer, P.; Imran, A.; Iriarte, A.; Karn, P.; Kieda, D.; Kunde, G. J.; Lara, A.; Lauer, R. J.; Lee, W. H.; Lennarz, D.; León Vargas, H.; Linares, E. C.; Linnemann, J. T.; Longo, M.; Luna-Garcia, R.; Marinelli, A.; Martinez, H.; Martinez, O.; Martínez-Castro, J.; Matthews, J. A. J.; McEnery, J.; Mendoza Torres, E.; Miranda-Romagnoli, P.; Moreno, E.; Mostafá, M.; Nellen, L.; Newbold, M.; Noriega-Papaqui, R.; Oceguera-Becerra, T.; Patricelli, B.; Pelayo, R.; Pérez-Pérez, E. G.; Pretz, J.; Rivière, C.; Rosa-González, D.; Ryan, J.; Salazar, H.; Salesa, F.; Sanchez, F. E.; Sandoval, A.; Schneider, M.; Silich, S.; Sinnis, G.; Smith, A. J.; Sparks Woodle, K.; Springer, R. W.; Taboada, I.; Toale, P. A.; Tollefson, K.; Torres, I.; Ukwatta, T. N.; Villaseñor, L.; Weisgarber, T.; Westerhoff, S.; Wisher, I. G.; Wood, J.; Yodh, G. B.; Younk, P. W.; Zaborov, D.; Zepeda, A.; Zhou, H.; Abazajian, K. N.; Milagro Collaboration

    2014-12-01

    The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19° North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi-TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from nonluminous dark matter subhalos. Here we consider the HAWC sensitivity to a subset of these sources, including dwarf galaxies, the M31 galaxy, the Virgo cluster, and the Galactic center. We simulate the HAWC response to gamma rays from these sources in several well-motivated dark matter annihilation channels. If no gamma-ray excess is observed, we show the limits HAWC can place on the dark matter cross section from these sources. In particular, in the case of dark matter annihilation into gauge bosons, HAWC will be able to detect a narrow range of dark matter masses to cross sections below thermal. HAWC should also be sensitive to nonthermal cross sections for masses up to nearly 1000 TeV. The constraints placed by HAWC on the dark matter cross section from known sources should be competitive with current limits in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.

  4. An UPLC-MS/MS method for highly sensitive high-throughput analysis of phytohormones in plant tissues

    Directory of Open Access Journals (Sweden)

    Balcke Gerd Ulrich

    2012-11-01

    Full Text Available Abstract Background Phytohormones are the key metabolites participating in the regulation of multiple functions of plant organism. Among them, jasmonates, as well as abscisic and salicylic acids are responsible for triggering and modulating plant reactions targeted against pathogens and herbivores, as well as resistance to abiotic stress (drought, UV-irradiation and mechanical wounding. These factors induce dramatic changes in phytohormone biosynthesis and transport leading to rapid local and systemic stress responses. Understanding of underlying mechanisms is of principle interest for scientists working in various areas of plant biology. However, highly sensitive, precise and high-throughput methods for quantification of these phytohormones in small samples of plant tissues are still missing. Results Here we present an LC-MS/MS method for fast and highly sensitive determination of jasmonates, abscisic and salicylic acids. A single-step sample preparation procedure based on mixed-mode solid phase extraction was efficiently combined with essential improvements in mobile phase composition yielding higher efficiency of chromatographic separation and MS-sensitivity. This strategy resulted in dramatic increase in overall sensitivity, allowing successful determination of phytohormones in small (less than 50 mg of fresh weight tissue samples. The method was completely validated in terms of analyte recovery, sensitivity, linearity and precision. Additionally, it was cross-validated with a well-established GC-MS-based procedure and its applicability to a variety of plant species and organs was verified. Conclusion The method can be applied for the analyses of target phytohormones in small tissue samples obtained from any plant species and/or plant part relying on any commercially available (even less sensitive tandem mass spectrometry instrumentation.

  5. Compact analytical model for single gate AlInSb/InSb high electron mobility transistors

    Institute of Scientific and Technical Information of China (English)

    S.Theodore Chandra; N.B.Balamurugan; G.Subalakshmi; T.Shalini; G.Lakshmi Priya

    2014-01-01

    We have developed a 2D analytical model for the single gate AlInSb/InSb HEMT device by solving the Poisson equation using the parabolic approximation method.The developed model analyses the device performance by calculating the parameters such as surface potential,electric field distribution and drain current.The high mobility of the AlInSb/InSb quantum makes this HEMT ideal for high frequency,high power applications.The working of the single gate AlInSb/InSb HEMT device is studied by considering the variation of gate source voltage,drain source voltage,and channel length under the gate region and temperature.The carrier transport efficiency is improved by uniform electric field along the channel and the peak values near the source and drain regions.The results from the analytical model are compared with that of numerical simulations (TCAD) and a good agreement between them is achieved.

  6. Project Title: Radiochemical Analysis by High Sensitivity Dual-Optic Micro X-ray Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George J.; Gao, Ning

    2003-06-01

    A novel dual-optic micro X-ray fluorescence instrument will be developed to do radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford. This concept incorporates new X-ray optical elements such as monolithic polycapillaries, which focus X-rays. The polycapillary optic can be used to focus X-rays emitted by the X-ray tube thereby increasing the X-ray flux on the sample over 1000 times. The polycapillary optic will also be used to collect the X-rays from the excitation site. This will effectively screen the radiation background from the radioactive species in the specimen. This dual-optic approach significantly reduces the background and increases the analyte signal thereby increasing the sensitivity of the analysis. This dual-capillary design is essentially a confocal (having the same foci) design, i.e. the detected X-rays are only emitted from the overlap of the two focal spots. This increases spatial resolution and reduce s background. The integration of the X-ray optics increases the signal-to-noise and thereby increases the sensitivity of the analysis for low-level analytes. This work will address a key need for radiochemical analysis of high-level waste using a non-destructive, multi-element, and rapid method in a radiation environment. There is significant potential that this instrumentation could be capable of on-line analysis for process waste stream characterization at DOE sites.

  7. Radiochemical Analysis by High Sensitivity Dual-Optic Micro X-ray Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George J.; Gao, Ning

    2004-06-01

    A novel dual-optic micro X-ray fluorescence instrument will be developed to do radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford. This concept incorporates new X-ray optical elements such as monolithic polycapillaries, which focus X-rays. The polycapillary optic can be used to focus X-rays emitted by the X-ray tube thereby increasing the X-ray flux on the sample over 1000 times. The polycapillary optic will also be used to collect the X-rays from the excitation site. This will effectively screen the radiation background from the radioactive species in the specimen. This dual-optic approach significantly reduces the background and increases the analyte signal thereby increasing the sensitivity of the analysis. This dual-capillary design is essentially a confocal (having the same foci) design, i.e. the detected X-rays are only emitted from the overlap of the two focal spots. This increases spatial resolution and reduces background. The integration of the X-ray optics increases the signal-to-noise and thereby increases the sensitivity of the analysis for low-level analytes. This work will address a key need for radiochemical analysis of high-level waste using a non-destructive, multi-element, and rapid method in a radiation environment. There is significant potential that this instrumentation could be capable of on-line analysis for process waste stream characterization at DOE sites.

  8. Integrating printed microfluidics with silicon photomultipliers for miniaturised and highly sensitive ATP bioluminescence detection.

    Science.gov (United States)

    Santangelo, M F; Libertino, S; Turner, A P F; Filippini, D; Mak, W C

    2018-01-15

    Bioluminescence has been widely used for important biosensing applications such as the measurement of adenosine triphosphate (ATP), the energy unit in biological systems and an indicator of vital processes. The current technology for detection is mainly based on large equipment such as readers and imaging systems, which require intensive and time-consuming procedures. A miniaturised bioluminescence sensing system, which would allow sensitive and continuous monitoring of ATP, with an integrated and low-cost disposable microfluidic chamber for handling of biological samples, is highly desirable. Here, we report the design, fabrication and testing of 3D printed microfluidics chips coupled with silicon photomultipliers (SiPMs) for high sensitive real-time ATP detection. The 3D microfluidic chip reduces reactant consumption and facilitates solution delivery close to the SiPM to increase the detection efficiency. Our system detects ATP with a limit of detection (LoD) of 8nM and an analytical dynamic range between 15nM and 1µM, showing a stability error of 3%, and a reproducibility error below of 20%. We demonstrate the dynamic monitoring of ATP in a continuous-flow system exhibiting a fast response time, ~4s, and a full recovery to the baseline level within 17s. Moreover, the SiPM-based bioluminescence sensing system shows a similar analytical dynamic range for ATP detection to that of a full-size PerkinElmer laboratory luminescence reader. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Molecular structure and thermodynamic predictions to create highly sensitive microRNA biosensors.

    Science.gov (United States)

    Larkey, Nicholas E; Brucks, Corinne N; Lansing, Shan S; Le, Sophia D; Smith, Natasha M; Tran, Victoria; Zhang, Lulu; Burrows, Sean M

    2016-02-25

    Many studies have established microRNAs (miRNAs) as post-transcriptional regulators in a variety of intracellular molecular processes. Abnormal changes in miRNA have been associated with several diseases. However, these changes are sometimes subtle and occur at nanomolar levels or lower. Several biosensing hurdles for in situ cellular/tissue analysis of miRNA limit detection of small amounts of miRNA. Of these limitations the most challenging are selectivity and sensor degradation creating high background signals and false signals. Recently we developed a reporter+probe biosensor for let-7a that showed potential to mitigate false signal from sensor degradation. Here we designed reporter+probe biosensors for miR-26a-2-3p and miR-27a-5p to better understand the effect of thermodynamics and molecular structures of the biosensor constituents on the analytical performance. Signal changes from interactions between Cy3 and Cy5 on the reporters were used to understand structural aspects of the reporter designs. Theoretical thermodynamic values, single stranded conformations, hetero- and homodimerization structures, and equilibrium concentrations of the reporters and probes were used to interpret the experimental observations. Studies of the sensitivity and selectivity revealed 5-9 nM detection limits in the presence and absence of interfering off-analyte miRNAs. These studies will aid in determining how to rationally design reporter+probe biosensors to overcome hurdles associated with highly sensitive miRNA biosensing.

  10. Data and Analytics to Inform Energy Retrofit of High Performance Buildings

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Tianzhen; Yang, Le; Hill, David; Feng, Wei

    2014-01-25

    Buildings consume more than one-third of the world?s primary energy. Reducing energy use in buildings with energy efficient technologies is feasible and also driven by energy policies such as energy benchmarking, disclosure, rating, and labeling in both the developed and developing countries. Current energy retrofits focus on the existing building stocks, especially older buildings, but the growing number of new high performance buildings built around the world raises a question that how these buildings perform and whether there are retrofit opportunities to further reduce their energy use. This is a new and unique problem for the building industry. Traditional energy audit or analysis methods are inadequate to look deep into the energy use of the high performance buildings. This study aims to tackle this problem with a new holistic approach powered by building performance data and analytics. First, three types of measured data are introduced, including the time series energy use, building systems operating conditions, and indoor and outdoor environmental parameters. An energy data model based on the ISO Standard 12655 is used to represent the energy use in buildings in a three-level hierarchy. Secondly, a suite of analytics were proposed to analyze energy use and to identify retrofit measures for high performance buildings. The data-driven analytics are based on monitored data at short time intervals, and cover three levels of analysis ? energy profiling, benchmarking and diagnostics. Thirdly, the analytics were applied to a high performance building in California to analyze its energy use and identify retrofit opportunities, including: (1) analyzing patterns of major energy end-use categories at various time scales, (2) benchmarking the whole building total energy use as well as major end-uses against its peers, (3) benchmarking the power usage effectiveness for the data center, which is the largest electricity consumer in this building, and (4) diagnosing HVAC

  11. Development, validation and application of a sensitive analytical method for residue determination and dissipation of imidacloprid in sugarcane under tropical field condition.

    Science.gov (United States)

    Ramasubramanian, T; Paramasivam, M; Nirmala, R

    2016-06-01

    A simple and sensitive analytical method has been developed and validated for the determination of trace amounts of imidacloprid in/on sugarcane sett, stalk and leaf. The method optimized in the present study requires less volume of organic solvent and time. Hence, this method is suitable for high-throughput analyses involving large number of samples. The limit of detection (LOD) and limit of quantification (LOQ) of the method were 0.003 and 0.01 mg/kg, respectively. The recovery and relative standard deviation were more than 93 % and less than 4 %, respectively. Thus, it is obvious that the analytical method standardized in this study is more precise and accurate enough to determine the residues of imidacloprid in sugarcane sett, stalk and leaf. The dissipation and translocation of imidacloprid residues from treated cane setts to leaf and stalk were studied by adopting this method. In sugarcane setts, the residues of imidacloprid persisted up to 120 days with half-life of 15.4 days at its recommended dose (70 g a.i./ha). The residues of imidacloprid were found to be translocated from setts to stalk and leaf. The imidacloprid residues were detected up to 105 days in both leaf and stalk. Dipping of sugarcane setts in imidacloprid at its recommended dose may result in better protection of cane setts and established crop because of higher initial deposit (>100 mg/kg) and longer persistence (>120 days).

  12. Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion

    Energy Technology Data Exchange (ETDEWEB)

    Kawahara, H.; Asada, T. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan); Naka, T. [Institute of Advanced Research, Nagoya University (Japan); Naganawa, N.; Kuwabara, K.; Nakamura, M. [Department of Physics, Nagoya University, Nagoya 464-8602 (Japan)

    2014-08-15

    Nuclear emulsion is a particle detector having high spacial resolution and angular resolution. It became useful for large statistics experiment thanks to the development of automatic scanning system. In 2010, a facility for emulsion production was introduced and R and D of nuclear emulsion began at Nagoya university. In this paper, we present results of development of the high sensitivity emulsion and fine grained emulsion for dark matter search experiment. Improvement of sensitivity is achieved by raising density of silver halide crystals and doping well-adjusted amount of chemicals. Production of fine grained emulsion was difficult because of unexpected crystal condensation. By mixing polyvinyl alcohol (PVA) to gelatin as a binder, we succeeded in making a stable fine grained emulsion.

  13. Highly sensitive troponin T in patients with acute ischemic stroke

    DEFF Research Database (Denmark)

    Jensen, J K; Ueland, T; Aukrust, P;

    2012-01-01

    in decedents than in survivors. After adjustment for stroke severity, C-reactive protein, age, NT-proBNP and prior heart and/or renal failure, hsTnT levels were not a significant predictor of long-term all-cause or cardiovascular mortality. Conclusion: Elevated levels of hsTnT are frequently present......Background: Newly developed troponin assays have superior diagnostic and prognostic performance in acute coronary syndrome (ACS), when compared to conventional troponin assays; however, highly sensitive troponin has not been evaluated in patients with acute ischemic stroke. Methods: Highly...... sensitive troponin T (hsTnT) was measured daily during the first 4 days in 193 consecutive patients with acute ischemic stroke without overt ACS or atrial fibrillation. The patients were previously tested normal with a fourth-generation TnT assay. The patients were followed for 47 months, with all...

  14. A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

    OpenAIRE

    Felisberto G. Santos; Boaventura F. Reis

    2017-01-01

    A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V) with thiocyanate ions (SCN−) in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm) to achieve high sensit...

  15. Highly Sensitive Flexible Magnetic Sensor Based on Anisotropic Magnetoresistance Effect.

    Science.gov (United States)

    Wang, Zhiguang; Wang, Xinjun; Li, Menghui; Gao, Yuan; Hu, Zhongqiang; Nan, Tianxiang; Liang, Xianfeng; Chen, Huaihao; Yang, Jia; Cash, Syd; Sun, Nian-Xiang

    2016-11-01

    A highly sensitive flexible magnetic sensor based on the anisotropic magnetoresistance effect is fabricated. A limit of detection of 150 nT is observed and excellent deformation stability is achieved after wrapping of the flexible sensor, with bending radii down to 5 mm. The flexible AMR sensor is used to read a magnetic pattern with a thickness of 10 μm that is formed by ferrite magnetic inks.

  16. Recent trends in high spin sensitivity magnetic resonance

    Science.gov (United States)

    Blank, Aharon; Twig, Ygal; Ishay, Yakir

    2017-07-01

    new ideas, show how these limiting factors can be mitigated to significantly improve the sensitivity of induction detection. Finally, we outline some directions for the possible applications of high-sensitivity induction detection in the field of electron spin resonance.

  17. Pulsed Discharge Helium Ionization Detector for Highly Sensitive Aquametry.

    Science.gov (United States)

    Mowry, Curtis D; Pimentel, Adam S; Sparks, Elizabeth S; Moorman, Matthew W; Achyuthan, Komandoor E; Manginell, Ronald P

    2016-01-01

    Trace moisture quantitation is crucial in medical, civilian and military applications. Current aquametry technologies are limited by the sample volume, reactivity, or interferences, and/or instrument size, weight, power, cost, and complexity. We report for the first time on the use of a pulsed discharge helium ionization detector (PDHID-D2) (∼196 cm(3)) for the sensitive (limit of detection, 0.047 ng; 26 ppm), linear (r(2) >0.99), and rapid (volume of liquid or gas. The relative humidity sensitivity was 0.22% (61.4 ppmv) with a limit of detection of less than 1 ng moisture with gaseous samples. The sensitivity was 10 to 100 to fold superior to competing technologies without the disadvantages inherent to these technologies. The PDHID-D2, due to its small footprint and low power requirement, has good size, weight, and power-portability (SWAPP) factors. The relatively low cost (∼$5000) and commercial availability of the PDHID-D2 makes our technique applicable to highly sensitive aquametry.

  18. An analytical inversion method for determining regional and global emissions of greenhouse gases: Sensitivity studies and application to halocarbons

    Directory of Open Access Journals (Sweden)

    A. Stohl

    2009-03-01

    Full Text Available A new analytical inversion method has been developed to determine the regional and global emissions of long-lived atmospheric trace gases. It exploits in situ measurement data from three global networks and builds on backward simulations with a Lagrangian particle dispersion model. The emission information is extracted from the observed concentration increases over a baseline that is itself objectively determined by the inversion algorithm. The method was applied to two hydrofluorocarbons (HFC-134a, HFC-152a and a hydrochlorofluorocarbon (HCFC-22 for the period January 2005 until March 2007. Detailed sensitivity studies with synthetic as well as with real measurement data were done to quantify the influence on the results of the a priori emissions and their uncertainties as well as of the observation and model errors. It was found that the global a posteriori emissions of HFC-134a, HFC-152a and HCFC-22 all increased from 2005 to 2006. Large increases (21%, 16%, 18%, respectively from 2005 to 2006 were found for China, whereas the emission changes in North America (−9%, 23%, 17%, respectively and Europe (11%, 11%, −4%, respectively were mostly smaller and less systematic. For Europe, the a posteriori emissions of HFC-134a and HFC-152a were slightly higher than the a priori emissions reported to the United Nations Framework Convention on Climate Change (UNFCCC. For HCFC-22, the a posteriori emissions for Europe were substantially (by almost a factor 2 higher than the a priori emissions used, which were based on HCFC consumption data reported to the United Nations Environment Programme (UNEP. Combined with the reported strongly decreasing HCFC consumption in Europe, this suggests a substantial time lag between the reported time of the HCFC-22 consumption and the actual time of the HCFC-22 emission. Conversely, in China where HCFC consumption is increasing rapidly according to the UNEP data, the a posteriori emissions are only about 40% of the a

  19. Development of a highly sensitive galvanic cell oxygen sensor.

    Science.gov (United States)

    Ogino, H; Asakura, K

    1995-02-01

    A highly sensitive galvanic cell oxygen sensor was successfully developed for determining parts per billion of oxygen in high purity gases such as nitrogen, argon, etc. The response of this improved sensor was proportional in the range of oxygen concentrations from 10.0 ppm to the detection limit. The response speed in this study was improved to within 90 sec for a 90% response. The detection limit was tentatively found to be less than 0.4 ppb corresponding to S N = 2 .

  20. A novel analytical approximation technique for highly nonlinear oscillators based on the energy balance method

    Science.gov (United States)

    Hosen, Md. Alal; Chowdhury, M. S. H.; Ali, Mohammad Yeakub; Ismail, Ahmad Faris

    In the present paper, a novel analytical approximation technique has been proposed based on the energy balance method (EBM) to obtain approximate periodic solutions for the focus generalized highly nonlinear oscillators. The expressions of the natural frequency-amplitude relationship are obtained using a novel analytical way. The accuracy of the proposed method is investigated on three benchmark oscillatory problems, namely, the simple relativistic oscillator, the stretched elastic wire oscillator (with a mass attached to its midpoint) and the Duffing-relativistic oscillator. For an initial oscillation amplitude A0 = 100, the maximal relative errors of natural frequency found in three oscillators are 2.1637%, 0.0001% and 1.201%, respectively, which are much lower than the errors found using the existing methods. It is highly remarkable that an excellent accuracy of the approximate natural frequency has been found which is valid for the whole range of large values of oscillation amplitude as compared with the exact ones. Very simple solution procedure and high accuracy that is found in three benchmark problems reveal the novelty, reliability and wider applicability of the proposed analytical approximation technique.

  1. CMOS Amperometric ADC With High Sensitivity, Dynamic Range and Power Efficiency for Air Quality Monitoring.

    Science.gov (United States)

    Li, Haitao; Boling, C Sam; Mason, Andrew J

    2016-08-01

    Airborne pollutants are a leading cause of illness and mortality globally. Electrochemical gas sensors show great promise for personal air quality monitoring to address this worldwide health crisis. However, implementing miniaturized arrays of such sensors demands high performance instrumentation circuits that simultaneously meet challenging power, area, sensitivity, noise and dynamic range goals. This paper presents a new multi-channel CMOS amperometric ADC featuring pixel-level architecture for gas sensor arrays. The circuit combines digital modulation of input currents and an incremental Σ∆ ADC to achieve wide dynamic range and high sensitivity with very high power efficiency and compact size. Fabricated in 0.5 [Formula: see text] CMOS, the circuit was measured to have 164 dB cross-scale dynamic range, 100 fA sensitivity while consuming only 241 [Formula: see text] and 0.157 [Formula: see text] active area per channel. Electrochemical experiments with liquid and gas targets demonstrate the circuit's real-time response to a wide range of analyte concentrations.

  2. Performance of terahertz metamaterials as high-sensitivity sensor

    Science.gov (United States)

    He, Yanan; Zhang, Bo; Shen, Jingling

    2017-09-01

    A high-sensitivity sensor based on the resonant transmission characteristics of terahertz (THz) metamaterials was investigated, with the proposal and fabrication of rectangular bar arrays of THz metamaterials exhibiting a period of 180 μm on a 25 μm thick flexible polyimide. Varying the size of the metamaterial structure revealed that the length of the rectangular unit modulated the resonant frequency, which was verified by both experiment and simulation. The sensing characteristics upon varying the surrounding media in the sample were tested by simulation and experiment. Changing the surrounding medium from that of air to that of alcohol or oil produced resonant frequency redshifts of 80 GHz or 150 GHz, respectively, which indicates that the sensor possessed a high sensitivity of 667 GHz per unit of refractive index. Finally, the influence of the sample substrate thickness on the sensor sensitivity was investigated by simulation. It may be a reference for future sensor design.

  3. High-sensitivity strain visualization using electroluminescence technologies

    Science.gov (United States)

    Xu, Jian; Jo, Hongki

    2016-04-01

    Visualizing mechanical strain/stress changes is an emerging area in structural health monitoring. Several ways are available for strain change visualization through the color/brightness change of the materials subjected to the mechanical stresses, for example, using mechanoluminescence (ML) materials and mechanoresponsive polymers (MRP). However, these approaches were not effectively applicable for civil engineering system yet, due to insufficient sensitivity to low-level strain of typical civil structures and limitation in measuring both static and dynamic strain. In this study, design and validation for high-sensitivity strain visualization using electroluminescence technologies are presented. A high-sensitivity Wheatstone bridge, of which bridge balance is precisely controllable circuits, is used with a gain-adjustable amplifier. The monochrome electroluminescence (EL) technology is employed to convert both static and dynamic strain change into brightness/color change of the EL materials, through either brightness change mode (BCM) or color alternation mode (CAM). A prototype has been made and calibrated in lab, the linearity between strain and brightness change has been investigated.

  4. High-sensitive scanning laser magneto-optical imaging system.

    Science.gov (United States)

    Murakami, Hironaru; Tonouchi, Masayoshi

    2010-01-01

    A high-sensitive scanning laser magneto-optical (MO) imaging system has been developed. The system is mainly composed of a laser source, galvano meters, and a high-sensitive differential optical-detector. Preliminary evaluation of system performance by using a Faraday indicator with a Faraday rotation coefficient of 3.47 x 10(-5) rad/microm Oe shows a magnetic sensitivity of about 5 microT, without any need for accumulation or averaging processing. Using the developed MO system we have succeeded in the fast and quantitative imaging of a rotationally symmetric magnetic field distribution around an YBa(2)Cu(3)O(7-delta) (YBCO) strip line applied with dc-biased current, and also succeeded in the detection of quantized fine signals corresponding to magnetic flux quantum generation in a superconducting loop of an YBCO Josephson vortex flow transistor. Thus, the developed system enables us not only to do fast imaging and local signal detection but also to directly evaluate both the strength and direction of a magnetic signal.

  5. HIGHLY SENSITIVE CATALASE ELECTRODE BASED ON POLYPYRROLE FILMS WITH MICROCONTAINERS

    Institute of Scientific and Technical Information of China (English)

    Yu-ying Gao; Gao-quan Shi

    2006-01-01

    Highly sensitive catalase electrodes for sensing hydrogen peroxide have been fabricated based on polypyrrole films with microcontainers. The microcontainers have a cup-like morphology and are arranged in a density of 4000 units cm-2.Catalase was immobilized into the polypyrrole films with microcontainers (Ppy-mc), which were coated on a Pt substrate electrode. The catalase/Ppy-mc/Pt electrode showed linear response to hydrogen peroxide in the range of 0-18 mmol/L at a potential of -0.3 V (versus SCE). Its sensitivity was measured to be approximately 3.64 μA (mmol/L)-1 cm-2, which is about two times that of the electrode fabricated from a flat Ppy film (catalase/Ppy-flat/Pt electrode). The electrode is highly selective for hydrogen peroxide and its sensitivity is interfered by potential interferents such as ascorbic acid, urea and fructose. Furthermore, such catalase electrodes showed long-term storage stability of 15 days under dry conditions at 4℃.

  6. Infiltrated photonic crystal cavity as a highly sensitive platform for glucose concentration detection

    Science.gov (United States)

    Arafa, Safia; Bouchemat, Mohamed; Bouchemat, Touraya; Benmerkhi, Ahlem; Hocini, Abdesselam

    2017-02-01

    A Bio-sensing platform based on an infiltrated photonic crystal ring shaped holes cavity-coupled waveguide system is proposed for glucose concentration detection. Considering silicon-on-insulator (SOI) technology, it has been demonstrated that the ring shaped holes configuration provides an excellent optical confinement within the cavity region, which further enhances the light-matter interactions at the precise location of the analyte medium. Thus, the sensitivity and the quality factor (Q) can be significantly improved. The transmission characteristics of light in the biosensor under different refractive indices that correspond to the change in the analyte glucose concentration are analyzed by performing finite-difference time-domain (FDTD) simulations. Accordingly, an improved sensitivity of 462 nm/RIU and a Q factor as high as 1.11х105 have been achieved, resulting in a detection limit of 3.03х10-6 RIU. Such combination of attributes makes the designed structure a promising element for performing label-free biosensing in medical diagnosis and environmental monitoring.

  7. Graphene prepared by one-pot solvent exfoliation as a highly sensitive platform for electrochemical sensing

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Can; Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Wu, Gang [Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Li, Qing, E-mail: qing_li_2@brown.edu [Materials Physics and Applications Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2014-05-01

    Highlights: • Graphene was prepared by one-step solvent exfoliation as superior electrode material. • Compared with RGO, prepared graphene exhibited stronger signal enhancement. • A widespread and highly-sensitive electrochemical sensing platform was constructed. - Abstract: Graphene was easily obtained via one-step ultrasonic exfoliation of graphite powder in N-methyl-2-pyrrolidone. Scanning electron microscopy, transmission electron microscopy, Raman and particle size measurements indicated that the exfoliation efficiency and the amount of produced graphene increased with ultrasonic time. The electrochemical properties and analytical applications of the resulting graphene were systematically studied. Compared with the predominantly-used reduced graphene oxides, the obtained graphene by one-step solvent exfoliation greatly enhanced the oxidation signals of various analytes, such as ascorbic acid (AA), dopamine (DA), uric acid (UA), xanthine (XA), hypoxanthine (HXA), bisphenol A (BPA), ponceau 4R, and sunset yellow. The detection limits of AA, DA, UA, XA, HXA, BPA, ponceau 4R, and sunset yellow were evaluated to be 0.8 μM, 7.5 nM, 2.5 nM, 4 nM, 10 nM, 20 nM, 2 nM, and 1 nM, which are much lower than the reported values. Thus, the prepared graphene via solvent exfoliation strategy displays strong signal amplification ability and holds great promise in constructing a universal and sensitive electrochemical sensing platform.

  8. Development of highly sensitive monolithic interferometer for infrared planet search

    Directory of Open Access Journals (Sweden)

    Jiang P.

    2011-07-01

    Full Text Available We present the design, fabrication and testing of a highly sensitive monolithic interferometer for InfraRed Exoplanet Tracker (IR-ET. This interferometer is field-compensated, thermal-stable for working in the wavelength range between 0.8 and 1.35 μm. Two arms of the interferometer creates a fixed delay of 18.0 mm, which is optimized to have the best sensitivity for radial velocity measurements of slow-rotating M dwarfs for planet detection. IR-ET is aiming to reach 3–20 m/s Doppler precision for J<10 M dwarfs in less than 15 min exposures. We plan to conduct a planet survey around hundreds of nearby M dwarfs through collaborations with Astrophysical Research Consortium scientists in 2011–2014.

  9. Polymer-Particle Pressure-Sensitive Paint with High Photostability

    Directory of Open Access Journals (Sweden)

    Yu Matsuda

    2016-04-01

    Full Text Available We propose a novel fast-responding and paintable pressure-sensitive paint (PSP based on polymer particles, i.e. polymer-particle (pp-PSP. As a fast-responding PSP, polymer-ceramic (PC-PSP is widely studied. Since PC-PSP generally consists of titanium (IV oxide (TiO2 particles, a large reduction in the luminescent intensity will occur due to the photocatalytic action of TiO2. We propose the usage of polymer particles instead of TiO2 particles to prevent the reduction in the luminescent intensity. Here, we fabricate pp-PSP based on the polystyrene particle with a diameter of 1 μm, and investigate the pressure- and temperature-sensitives, the response time, and the photostability. The performances of pp-PSP are compared with those of PC-PSP, indicating the high photostability with the other characteristics comparable to PC-PSP.

  10. New application of superconductors: high sensitivity cryogenic light detectors

    CERN Document Server

    Cardani, L; Casali, N; Casellano, M G; Colantoni, I; Coppolecchia, A; Cosmelli, C; Cruciani, A; D'Addabbo, A; Di Domizio, S; Martinez, M; Tomei, C; Vignati, M

    2016-01-01

    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs), that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results ob...

  11. Highly sensitive detection of urinary cadmium to assess personal exposure

    Energy Technology Data Exchange (ETDEWEB)

    Argun, Avni A.; Banks, Ashley M.; Merlen, Gwendolynne; Tempelman, Linda A. [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States); Becker, Michael F.; Schuelke, Thomas [Fraunhofer USA – CCL, 1449 Engineering Research Ct., East Lansing 48824, MI (United States); Dweik, Badawi M., E-mail: bdweik@ginerinc.com [Giner, Inc., 89 Rumford Ave., Newton 02466, MA United States (United States)

    2013-04-22

    Highlights: ► An electrochemical sensor capable of detecting cadmium at parts-per-billion levels in urine. ► A novel fabrication method for Boron-Doped Diamond (BDD) ultramicroelectrode (UME) arrays. ► Unique combination of BDD UME arrays and a differential pulse voltammetry algorithm. ► High sensitivity, high reproducibility, and very low noise levels. ► Opportunity for portable operation to assess on-site personal exposure. -- Abstract: A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 μA ppb{sup −1} cm{sup −2}) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium.

  12. Highly sensitive assay for the measurement of serotonin in microdialysates using capillary high-performance liquid chromatography with electrochemical detection.

    Science.gov (United States)

    Parrot, Sandrine; Lambás-Señas, Laura; Sentenac, Sabine; Denoroy, Luc; Renaud, Bernard

    2007-05-01

    A highly sensitive isocratic capillary high-performance liquid chromatographic (HPLC) method with electrochemical detection (ED) for the simultaneous measurement of serotonin (5-hydroxytryptamine, 5-HT) and its metabolite 5-hydroxyindole-3-acetic acid (5-HIAA) in microdialysates has been developed using a 0.5 mm i.d. capillary column and a 11-nL detection cell. This method, validated on both pharmacological and analytical bases, can be performed using injection volumes as low as 1 microL. The limits of detection were 5.6 x 10(-11)mol/L and 3.0 x 10(-9)mol/L for 5-HT and 5-HIAA. Several applications of the present method are given on microdialysates from rodent brain and human spinal cord.

  13. A technique coupling the analyte electrodeposition followed by in-situ stripping with electrothermal atomic absorption spectrometry for analysis of samples with high NaCl contents

    Science.gov (United States)

    Čánský, Zdeněk; Rychlovský, Petr; Petrová, Zuzana; Matousek, J. P.

    2007-03-01

    A technique coupling the analyte electrodeposition followed by in-situ stripping with electrothermal atomic absorption spectrometry has been developed for determination of lead and cadmium in samples with high salt contents. To separate the analyte from the sample matrix, the analyte was in-situ quantitatively electrodeposited on a platinum sampling capillary serving as the cathode (sample volume, 20 μL). The spent electrolyte containing the sample matrix was then withdrawn, the capillary with the analyte deposited was washed with deionized water and the analyte was stripped into a chemically simple electrolyte (5 g/L NH 4H 2PO 4) by reversing the polarity of the electrodeposition circuit. Electrothermal atomization using a suitable optimized temperature program followed. A fully automated manifold was designed for this coupled technique and the appropriate control software was developed. The operating conditions for determination of Pb and Cd in samples with high contents of inorganic salts were optimized, the determination was characterized by principal analytical parameters and its applicability was verified on analyses of urine reference samples. The absolute limits of detection for lead and cadmium (3 σ criterion) in a sample containing 30 g/L NaCl were 8.5 pg and 2.3 pg, respectively (peak absorbance) and the RSD values amounted to 1.6% and 1.9% for lead (at the 40 ng mL - 1 level) and cadmium (at the 4.0 ng mL - 1 level), respectively. These values (and also the measuring sensitivity) are superior to the results attained in conventional electrothermal atomic absorption spectrometric determination of Pb and Cd in pure solutions (5 g/L NH 4H 2PO 4). The sensitivity of the Pb and Cd determination is not affected by the NaCl concentration up to a value of 100 g/L, demonstrating an efficient matrix removal during the electrodeposition step.

  14. Upconverting nanophosphors as reporters in a highly sensitive heterogeneous immunoassay for cardiac troponin I

    Energy Technology Data Exchange (ETDEWEB)

    Sirkka, Nina, E-mail: nkelon@utu.fi; Lyytikäinen, Annika; Savukoski, Tanja; Soukka, Tero

    2016-06-21

    Photon upconverting nanophosphors (UCNPs) have a unique capability to produce anti-Stokes emission at visible wavelengths via sequential multiphoton absorption upon infrared excitation. Since the anti-Stokes emission can be easily spectrally resolved from the Stokes' shifted autofluorescence, the upconversion luminescence (UCL) is a highly attractive reporter technology for optical biosensors and biomolecular binding assays – potentially enabling unprecedented sensitivity in separation-based solid-phase immunoassays. UCL technology has not previously been applied in sensitive detection of cardiac troponin I (cTnI), which requires highly sensitive detection to enable accurate and timely diagnosis of myocardial infarction. We have developed an UCL-based immunoassay for cTnI using NaYF{sub 4}: Yb{sup 3+}, Er{sup 3+} UCNPs as reporters. Biotinylated anti-cTnI monoclonal antibody (Mab) and Fab fragment immobilized to streptavidin-coated wells were used to capture cTnI. Captured cTnI was detected from dry well surface after a 15 min incubation with poly(acrylic acid) coated UCNPs conjugated to second anti-cTnI Mab. UCL was measured with a dedicated UCL microplate reader. The UCL-based immunoassay allowed sensitive detection of cTnI. The limit of detection was 3.14 ng L{sup −1}. The calibration curve was linear up to cTnI concentration 50,000 ng L{sup −1}. Plasma recoveries of added cTnI were 92–117%. Obtained cTnI concentrations from five normal plasma samples were 4.13–10.7 ng L{sup −1} (median 5.06 ng L{sup −1}). There is yet significant potential for even further improved limit of detection by reducing non-specifically bound fraction of the Mab-conjugated UCNPs. The assay background with zero calibrator was over 40-fold compared to the background obtained from wells where the reporter conjugate had been excluded. - Highlights: • Detection of attomole analyte quantity in microwell using upconversion luminescence. • Upconverting

  15. Analytical thermal modelling of multilayered active embedded chips into high density electronic board

    Directory of Open Access Journals (Sweden)

    Monier-Vinard Eric

    2013-01-01

    Full Text Available The recent Printed Wiring Board embedding technology is an attractive packaging alternative that allows a very high degree of miniaturization by stacking multiple layers of embedded chips. This disruptive technology will further increase the thermal management challenges by concentrating heat dissipation at the heart of the organic substrate structure. In order to allow the electronic designer to early analyze the limits of the power dissipation, depending on the embedded chip location inside the board, as well as the thermal interactions with other buried chips or surface mounted electronic components, an analytical thermal modelling approach was established. The presented work describes the comparison of the analytical model results with the numerical models of various embedded chips configurations. The thermal behaviour predictions of the analytical model, found to be within ±10% of relative error, demonstrate its relevance for modelling high density electronic board. Besides the approach promotes a practical solution to study the potential gain to conduct a part of heat flow from the components towards a set of localized cooled board pads.

  16. Teachable, high-content analytics for live-cell, phase contrast movies.

    Science.gov (United States)

    Alworth, Samuel V; Watanabe, Hirotada; Lee, James S J

    2010-09-01

    CL-Quant is a new solution platform for broad, high-content, live-cell image analysis. Powered by novel machine learning technologies and teach-by-example interfaces, CL-Quant provides a platform for the rapid development and application of scalable, high-performance, and fully automated analytics for a broad range of live-cell microscopy imaging applications, including label-free phase contrast imaging. The authors used CL-Quant to teach off-the-shelf universal analytics, called standard recipes, for cell proliferation, wound healing, cell counting, and cell motility assays using phase contrast movies collected on the BioStation CT and BioStation IM platforms. Similar to application modules, standard recipes are intended to work robustly across a wide range of imaging conditions without requiring customization by the end user. The authors validated the performance of the standard recipes by comparing their performance with truth created manually, or by custom analytics optimized for each individual movie (and therefore yielding the best possible result for the image), and validated by independent review. The validation data show that the standard recipes' performance is comparable with the validated truth with low variation. The data validate that the CL-Quant standard recipes can provide robust results without customization for live-cell assays in broad cell types and laboratory settings.

  17. Analytical Study of High Pitch Delay Resolution Technique for Tonal Speech Coding

    Directory of Open Access Journals (Sweden)

    Suphattharachai Chomphan

    2012-01-01

    Full Text Available Problem statement: In tonal-language speech, since tone plays important role not only on the naturalness and also the intelligibility of the speech, it must be treated appropriately in a speech coder algorithm. Approach: This study proposes an analytical study of the technique of High Pitch Delay Resolutions (HPDR applied to the adaptive codebook of core coder of Multi-Pulse based Code Excited Linear Predictive (MP-CELP coder. Results: The experimental results show that the speech quality of the MP-CELP speech coder with HPDR technique is improved above the speech quality of the conventional coder. An optimum resolution of pitch delay is also presented. Conclusion: From the analytical study, it has been found that the proposed technique can improve the speech coding quality.

  18. Influence of Smoking on Ultra-High-Frequency Auditory Sensitivity.

    Science.gov (United States)

    Prabhu, Prashanth; Varma, Gowtham; Dutta, Kristi Kaveri; Kumar, Prajwal; Goyal, Swati

    2017-04-01

    In this study, an attempt was made to determine the effect of smoking on ultra-high-frequency auditory sensitivity. The study also attempted to determine the relationship between the nature of smoking and ultra-high-frequency otoacoustic emissions (OAEs) and thresholds. The study sample included 25 smokers and 25 non-smokers. A detailed history regarding their smoking habits was collected. High-frequency audiometric thresholds and amplitudes of high-frequency distortion-product OAEs were analyzed for both ears from all participants. The results showed that the ultra-high-frequency thresholds were elevated and that there was reduction in the amplitudes of ultra-high-frequency OAEs in smokers. There was an increased risk of auditory damage with chronic smoking. The study results highlight the application of ultra-high-frequency OAEs and ultra-high-frequency audiometry for the early detection of auditory impairment. However, similar studies should be conducted on a larger population for better generalization of the results.

  19. The Convergence of High Performance Computing and Large Scale Data Analytics

    Science.gov (United States)

    Duffy, D.; Bowen, M. K.; Thompson, J. H.; Yang, C. P.; Hu, F.; Wills, B.

    2015-12-01

    As the combinations of remote sensing observations and model outputs have grown, scientists are increasingly burdened with both the necessity and complexity of large-scale data analysis. Scientists are increasingly applying traditional high performance computing (HPC) solutions to solve their "Big Data" problems. While this approach has the benefit of limiting data movement, the HPC system is not optimized to run analytics, which can create problems that permeate throughout the HPC environment. To solve these issues and to alleviate some of the strain on the HPC environment, the NASA Center for Climate Simulation (NCCS) has created the Advanced Data Analytics Platform (ADAPT), which combines both HPC and cloud technologies to create an agile system designed for analytics. Large, commonly used data sets are stored in this system in a write once/read many file system, such as Landsat, MODIS, MERRA, and NGA. High performance virtual machines are deployed and scaled according to the individual scientist's requirements specifically for data analysis. On the software side, the NCCS and GMU are working with emerging commercial technologies and applying them to structured, binary scientific data in order to expose the data in new ways. Native NetCDF data is being stored within a Hadoop Distributed File System (HDFS) enabling storage-proximal processing through MapReduce while continuing to provide accessibility of the data to traditional applications. Once the data is stored within HDFS, an additional indexing scheme is built on top of the data and placed into a relational database. This spatiotemporal index enables extremely fast mappings of queries to data locations to dramatically speed up analytics. These are some of the first steps toward a single unified platform that optimizes for both HPC and large-scale data analysis, and this presentation will elucidate the resulting and necessary exascale architectures required for future systems.

  20. High-Speed Rotor Analytical Dynamics on Flexible Foundation Subjected to Internal and External Excitation

    Science.gov (United States)

    Jivkov, Venelin S.; Zahariev, Evtim V.

    2016-12-01

    The paper presents a geometrical approach to dynamics simulation of a rigid and flexible system, compiled of high speed rotating machine with eccentricity and considerable inertia and mass. The machine is mounted on a vertical flexible pillar with considerable height. The stiffness and damping of the column, as well as, of the rotor bearings and the shaft are taken into account. Non-stationary vibrations and transitional processes are analyzed. The major frequency and modal mode of the flexible column are used for analytical reduction of its mass, stiffness and damping properties. The rotor and the foundation are modelled as rigid bodies, while the flexibility of the bearings is estimated by experiments and the requirements of the manufacturer. The transition effects as a result of limited power are analyzed by asymptotic methods of averaging. Analytical expressions for the amplitudes and unstable vibrations throughout resonance are derived by quasi-static approach increasing and decreasing of the exciting frequency. Analytical functions give the possibility to analyze the influence of the design parameter of many structure applications as wind power generators, gas turbines, turbo-generators, and etc. A numerical procedure is applied to verify the effectiveness and precision of the simulation process. Nonlinear and transitional effects are analyzed and compared to the analytical results. External excitations, as wave propagation and earthquakes, are discussed. Finite elements in relative and absolute coordinates are applied to model the flexible column and the high speed rotating machine. Generalized Newton - Euler dynamics equations are used to derive the precise dynamics equations. Examples of simulation of the system vibrations and nonstationary behaviour are presented.

  1. Big data in health care: using analytics to identify and manage high-risk and high-cost patients.

    Science.gov (United States)

    Bates, David W; Saria, Suchi; Ohno-Machado, Lucila; Shah, Anand; Escobar, Gabriel

    2014-07-01

    The US health care system is rapidly adopting electronic health records, which will dramatically increase the quantity of clinical data that are available electronically. Simultaneously, rapid progress has been made in clinical analytics--techniques for analyzing large quantities of data and gleaning new insights from that analysis--which is part of what is known as big data. As a result, there are unprecedented opportunities to use big data to reduce the costs of health care in the United States. We present six use cases--that is, key examples--where some of the clearest opportunities exist to reduce costs through the use of big data: high-cost patients, readmissions, triage, decompensation (when a patient's condition worsens), adverse events, and treatment optimization for diseases affecting multiple organ systems. We discuss the types of insights that are likely to emerge from clinical analytics, the types of data needed to obtain such insights, and the infrastructure--analytics, algorithms, registries, assessment scores, monitoring devices, and so forth--that organizations will need to perform the necessary analyses and to implement changes that will improve care while reducing costs. Our findings have policy implications for regulatory oversight, ways to address privacy concerns, and the support of research on analytics. Project HOPE—The People-to-People Health Foundation, Inc.

  2. Ultrathin plasmonic nanogratings for rapid and highly-sensitive detection

    CERN Document Server

    Zeng, Beibei; Bartoli, Filbert J

    2014-01-01

    We developed a nanoplasmonic sensor platform employing the extraordinary optical properties of one-dimensional nanogratings patterned on 30nm-thick ultrathin Ag films. Excitation of Fano resonances in the ultrathin Ag nanogratings results in transmission spectra with high amplitude, large contrast, and narrow bandwidth, making them well-suited for rapid and highly-sensitive sensing applications. The ultrathin nanoplasmonic sensor chip was integrated with a polydimethylsiloxane (PDMS) microfluidic channel, and the measured refractive index resolution was found to be 1.46x10-6 refractive index units (RIU) with a high temporal resolution of 1 sec. This compares favorably with commercial prism-based surface plasmon resonance sensors, but is achieved using a more convenient collinear transmission geometry and a significantly smaller sensor footprint of 50x50um2. In addition, an order-of-magnitude improvement in the temporal and spatial resolutions was achieved relative to state-of-the-art nanoplasmonic sensors, fo...

  3. Potential programs for high sensitivity FIR spectroscopy with SPICA

    CERN Document Server

    Spinoglio, L; Saraceno, P; Spinoglio, Luigi; Giorgio, Anna Maria Di; Saraceno, Paolo

    2006-01-01

    We discuss the potential of high sensitivity mid-IR and far-IR spectroscopy to proof the physical properties of active nuclei and starburst regions of local and distant galaxies. For local galaxies, it will be possible to map the discs and ISM through the low ionization ionic lines and a variety of molecular tracers, such as OH, H2O and high-J CO. At increasing distance, most of the ionic nebular lines (typical of stars and AGNs) are shifted into the FIR, making possible to compare the observed spectra with those predicted by different evolutionary scenarios. At the very high redshift of 10-15, sensitive mid-to-far-IR spectrometers, such as those planned to be at the focal plane of the future SPICA mision, could be adequate to detect the H recombination lines excited in the HII regions around population III stars, if these stars happened to reside in large clusters of more than 10^5 members.

  4. High-sensitivity piezoelectric perovskites for magnetoelectric composites

    Science.gov (United States)

    Amorín, Harvey; Algueró, Miguel; Campo, Rubén Del; Vila, Eladio; Ramos, Pablo; Dollé, Mickael; Romaguera-Barcelay, Yonny; Cruz, Javier Pérez De La; Castro, Alicia

    2015-01-01

    A highly topical set of perovskite oxides are high-sensitivity piezoelectric ones, among which Pb(Zr,Ti)O3 at the morphotropic phase boundary (MPB) between ferroelectric rhombohedral and tetragonal polymorphic phases is reckoned a case study. Piezoelectric ceramics are used in a wide range of mature, electromechanical transduction technologies like piezoelectric sensors, actuators and ultrasound generation, to name only a few examples, and more recently for demonstrating novel applications like magnetoelectric composites. In this case, piezoelectric perovskites are combined with magnetostrictive materials to provide magnetoelectricity as a product property of the piezoelectricity and piezomagnetism of the component phases. Interfaces play a key issue, for they control the mechanical coupling between the piezoresponsive phases. We present here main results of our investigation on the suitability of the high sensitivity MPB piezoelectric perovskite BiScO3–PbTiO3 in combination with ferrimagnetic spinel oxides for magnetoelectric composites. Emphasis has been put on the processing at low temperature to control reactions and interdiffusion between the two oxides. The role of the grain size effects is extensively addressed. PMID:27877758

  5. High-Sensitivity Measurement of Density by Magnetic Levitation.

    Science.gov (United States)

    Nemiroski, Alex; Kumar, A A; Soh, Siowling; Harburg, Daniel V; Yu, Hai-Dong; Whitesides, George M

    2016-03-01

    This paper presents methods that use Magnetic Levitation (MagLev) to measure very small differences in density of solid diamagnetic objects suspended in a paramagnetic medium. Previous work in this field has shown that, while it is a convenient method, standard MagLev (i.e., where the direction of magnetization and gravitational force are parallel) cannot resolve differences in density mm) because (i) objects close in density prevent each other from reaching an equilibrium height due to hard contact and excluded volume, and (ii) using weaker magnets or reducing the magnetic susceptibility of the medium destabilizes the magnetic trap. The present work investigates the use of weak magnetic gradients parallel to the faces of the magnets as a means of increasing the sensitivity of MagLev without destabilization. Configuring the MagLev device in a rotated state (i.e., where the direction of magnetization and gravitational force are perpendicular) relative to the standard configuration enables simple measurements along the axes with the highest sensitivity to changes in density. Manipulating the distance of separation between the magnets or the lengths of the magnets (along the axis of measurement) enables the sensitivity to be tuned. These modifications enable an improvement in the resolution up to 100-fold over the standard configuration, and measurements with resolution down to 10(-6) g/cm(3). Three examples of characterizing the small differences in density among samples of materials having ostensibly indistinguishable densities-Nylon spheres, PMMA spheres, and drug spheres-demonstrate the applicability of rotated Maglev to measuring the density of small (0.1-1 mm) objects with high sensitivity. This capability will be useful in materials science, separations, and quality control of manufactured objects.

  6. High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

    Directory of Open Access Journals (Sweden)

    R.F. Vogel

    2005-08-01

    Full Text Available Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacterium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress response, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to identify novel tools for high pressure biotechnology. To investigate the mechanisms of the complex bacterial response to high pressure we have analyzed changes in the proteome and transcriptome by 2-D electrophoresis, and by microarrays and real time PCR, respectively. More than 16 proteins were found to be differentially expressed upon high pressure stress and were compared to those sensitive to other stresses. Except for one apparently high pressure-specific stress protein, no pressure-specific stress proteins were found, and the proteome response to pressure was found to differ from that induced by other stresses. Selected pressure-sensitive proteins were partially sequenced and their genes were identified by reverse genetics. In a transcriptome analysis of a redundancy cleared shot gun library, about 7% of the genes investigated were found to be affected. Most of them appeared to be up-regulated 2- to 4-fold and these results were confirmed by real time PCR. Gene induction was shown for some genes up-regulated at the proteome level (clpL/groEL/rbsK, while the response of others to high hydrostatic pressure at the transcriptome level seemed to differ from that observed at the proteome level. The up-regulation of selected genes supports the view that the cell tries to compensate for pressure-induced impairment of translation and membrane transport.

  7. Analysis and Comprehensive Analytical Modeling of Statistical Variations in Subthreshold MOSFET's High Frequency Characteristics

    Directory of Open Access Journals (Sweden)

    Rawid Banchuin

    2014-01-01

    Full Text Available In this research, the analysis of statistical variations in subthreshold MOSFET's high frequency characteristics defined in terms of gate capacitance and transition frequency, have been shown and the resulting comprehensive analytical models of such variations in terms of their variances have been proposed. Major imperfection in the physical level properties including random dopant fluctuation and effects of variations in MOSFET's manufacturing process, have been taken into account in the proposed analysis and modeling. The up to dated comprehensive analytical model of statistical variation in MOSFET's parameter has been used as the basis of analysis and modeling. The resulting models have been found to be both analytic and comprehensive as they are the precise mathematical expressions in terms of physical level variables of MOSFET. Furthermore, they have been verified at the nanometer level by using 65~nm level BSIM4 based benchmarks and have been found to be very accurate with smaller than 5 % average percentages of errors. Hence, the performed analysis gives the resulting models which have been found to be the potential mathematical tool for the statistical and variability aware analysis and design of subthreshold MOSFET based VHF circuits, systems and applications.

  8. High-Speed Rotor Analytical Dynamics on Flexible Foundation Subjected to Internal and External Excitation

    Directory of Open Access Journals (Sweden)

    Jivkov Venelin S.

    2016-12-01

    Full Text Available The paper presents a geometrical approach to dynamics simulation of a rigid and flexible system, compiled of high speed rotating machine with eccentricity and considerable inertia and mass. The machine is mounted on a vertical flexible pillar with considerable height. The stiffness and damping of the column, as well as, of the rotor bearings and the shaft are taken into account. Non-stationary vibrations and transitional processes are analyzed. The major frequency and modal mode of the flexible column are used for analytical reduction of its mass, stiffness and damping properties. The rotor and the foundation are modelled as rigid bodies, while the flexibility of the bearings is estimated by experiments and the requirements of the manufacturer. The transition effects as a result of limited power are analyzed by asymptotic methods of averaging. Analytical expressions for the amplitudes and unstable vibrations throughout resonance are derived by quasi-static approach increasing and decreasing of the exciting frequency. Analytical functions give the possibility to analyze the influence of the design parameter of many structure applications as wind power generators, gas turbines, turbo-generators, and etc. A numerical procedure is applied to verify the effectiveness and precision of the simulation process.

  9. Experimental and analytical study of high velocity impact on Kevlar/Epoxy composite plates

    Science.gov (United States)

    Sikarwar, Rahul; Velmurugan, Raman; Madhu, Velmuri

    2012-12-01

    In the present study, impact behavior of Kevlar/Epoxy composite plates has been carried out experimentally by considering different thicknesses and lay-up sequences and compared with analytical results. The effect of thickness, lay-up sequence on energy absorbing capacity has been studied for high velocity impact. Four lay-up sequences and four thickness values have been considered. Initial velocities and residual velocities are measured experimentally to calculate the energy absorbing capacity of laminates. Residual velocity of projectile and energy absorbed by laminates are calculated analytically. The results obtained from analytical study are found to be in good agreement with experimental results. It is observed from the study that 0/90 lay-up sequence is most effective for impact resistance. Delamination area is maximum on the back side of the plate for all thickness values and lay-up sequences. The delamination area on the back is maximum for 0/90/45/-45 laminates compared to other lay-up sequences.

  10. Big data and high-performance analytics in structural health monitoring for bridge management

    Science.gov (United States)

    Alampalli, Sharada; Alampalli, Sandeep; Ettouney, Mohammed

    2016-04-01

    Structural Health Monitoring (SHM) can be a vital tool for effective bridge management. Combining large data sets from multiple sources to create a data-driven decision-making framework is crucial for the success of SHM. This paper presents a big data analytics framework that combines multiple data sets correlated with functional relatedness to convert data into actionable information that empowers risk-based decision-making. The integrated data environment incorporates near real-time streams of semi-structured data from remote sensors, historical visual inspection data, and observations from structural analysis models to monitor, assess, and manage risks associated with the aging bridge inventories. Accelerated processing of dataset is made possible by four technologies: cloud computing, relational database processing, support from NOSQL database, and in-memory analytics. The framework is being validated on a railroad corridor that can be subjected to multiple hazards. The framework enables to compute reliability indices for critical bridge components and individual bridge spans. In addition, framework includes a risk-based decision-making process that enumerate costs and consequences of poor bridge performance at span- and network-levels when rail networks are exposed to natural hazard events such as floods and earthquakes. Big data and high-performance analytics enable insights to assist bridge owners to address problems faster.

  11. Rituximab induction therapy in highly sensitized kidney transplant recipients

    Institute of Scientific and Technical Information of China (English)

    YIN Hang; WAN Hao; HU Xiao-peng; LI Xiao-bei; WANG Wei; LIU Hang; REN Liang; ZHANG Xiao-dong

    2011-01-01

    Background The number of highly sensitized patients is rising, and sensitization can lead to renal transplant failure.The present study aimed to investigate the safety and efficacy of renal transplantation following induction therapy with rituximab in highly sensitized kidney transplant recipients.Methods Seven highly sensitized kidney transplant recipients who underwent rituximab therapy from December 2008 to December 2009 were retrospectively analyzed. There were 3 men and 4 women, with a mean age of 38.5 years (range, 21-47 years). The duration of hemodialysis was 3-12 months, with a mean duration of 11 months. For 4 patients,this was the second transplant; the previous graft survival time was 2-11 years, with a mean survival time of 5.8 years. All the female recipients had history of multiple pregnancies, and all patients had previously received blood transfusions. All donors were men, with a mean age of 32.5 years (range, 25-37 years). In 2 of the 7 patients, both class I and class II of panel reactive antibody were high; the remaining 5 patients showed either high in class I or in class II of panel reactive antibody. The mean panel reactive antibody value was 31% for class I and 51% for class II respectively. The donors and the recipients had the same blood type, with low lymphocyte cytotoxicity ranging from 2% to 5%. The human leukocyte antigen (HLA) mismatch numbers were from 2 to 4. All patients received tacrolimus (0.1 mg·kg-1·d-1) and mycophenolate mofetil (750 mg twice per day) orally 3 days prior to surgery. All patients received a single dose of 600 mg rituximab (375 mg/m2) infusion on the day before surgery and polyclonal antibody (antithymocyte globulin) on the day of surgery.Postoperative creatinine, creatinine clearance rate, and occurrence of rejection by pathological biopsy confirmation were monitored.Results No patient had delayed graft function after surgery. Two patients had acute rejection, one on day 7 and the other on day 13 post

  12. Highly sensitive detection of Staphylococcus aureus directly from patient blood.

    Directory of Open Access Journals (Sweden)

    Padmapriya P Banada

    Full Text Available BACKGROUND: Rapid detection of bloodstream infections (BSIs can be lifesaving. We investigated the sample processing and assay parameters necessary for highly-sensitive detection of bloodstream bacteria, using Staphylococcus aureus as a model pathogen and an automated fluidic sample processing-polymerase chain reaction (PCR platform as a model diagnostic system. METHODOLOGY/PRINCIPAL FINDINGS: We compared a short 128 bp amplicon hemi-nested PCR and a relatively shorter 79 bp amplicon nested PCR targeting the S. aureus nuc and sodA genes, respectively. The sodA nested assay showed an enhanced limit of detection (LOD of 5 genomic copies per reaction or 10 colony forming units (CFU per ml blood over 50 copies per reaction or 50 CFU/ml for the nuc assay. To establish optimal extraction protocols, we investigated the relative abundance of the bacteria in different components of the blood (white blood cells (WBCs, plasma or whole blood, using the above assays. The blood samples were obtained from the patients who were culture positive for S. aureus. Whole blood resulted in maximum PCR positives with sodA assay (90% positive as opposed to cell-associated bacteria (in WBCs (71% samples positive or free bacterial DNA in plasma (62.5% samples positive. Both the assays were further tested for direct detection of S. aureus in patient whole blood samples that were contemporaneous culture positive. S. aureus was detected in 40/45 of culture-positive patients (sensitivity 89%, 95% CI 0.75-0.96 and 0/59 negative controls with the sodA assay (specificity 100%, 95% CI 0.92-1. CONCLUSIONS: We have demonstrated a highly sensitive two-hour assay for detection of sepsis causing bacteria like S. aureus directly in 1 ml of whole blood, without the need for blood culture.

  13. Coumarin-bearing triarylamine sensitizers with high molar extinction coefficient for dye-sensitized solar cells

    Science.gov (United States)

    Zhong, Changjian; Gao, Jianrong; Cui, Yanhong; Li, Ting; Han, Liang

    2015-01-01

    Coumarin unit is introduced into triarylamine and three organic sensitizers are designed and synthesized with triarylamine bearing coumarin moiety as the electron donor, conjugated system containing thiophene unit as the π-bridge, and cyanoacetic acid moiety as the electron acceptor. The light-harvesting capabilities and photovoltaic performance of these dyes are investigated systematically with the comparison of different π-bridges. High molar extinction coefficients are observed in these triarylamine dyes and the photocurrent and photovoltage are increased with the introduction of another thiophene or benzene. Optimal photovoltaic performance (η = 6.24%, Voc = 690 mV, Jsc = 14.33 mA cm-2, and ff = 0.63) is observed in the DSSC based on dye with thiophene-phenyl unit as the π-conjugated bridge under 100 mW cm-2 simulated AM 1.5 G solar irradiation.

  14. Highly Sensitive Assay for Measurement of Arenavirus-cell Attachment.

    Science.gov (United States)

    Klaus, Joseph P; Botten, Jason

    2016-03-02

    Arenaviruses are a family of enveloped RNA viruses that cause severe human disease. The first step in the arenavirus life cycle is attachment of viral particles to host cells. While virus-cell attachment can be measured through the use of virions labeled with biotin, radioactive isotopes, or fluorescent dyes, these approaches typically require high multiplicities of infection (MOI) to enable detection of bound virus. We describe a quantitative (q)RT-PCR-based assay that measures Junin virus strain Candid 1 attachment via quantitation of virion-packaged viral genomic RNA. This assay has several advantages including its extreme sensitivity and ability to measure attachment over a large dynamic range of MOIs without the need to purify or label input virus. Importantly, this approach can be easily tailored for use with other viruses through the use of virus-specific qRT-PCR reagents. Further, this assay can be modified to permit measurement of particle endocytosis and genome uncoating. In conclusion, we describe a simple, yet robust assay for highly sensitive measurement of arenavirus-cell attachment.

  15. Sensitivity study of reliable, high-throughput resolution metricsfor photoresists

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Christopher N.; Naulleau, Patrick P.

    2007-07-30

    The resolution of chemically amplified resists is becoming an increasing concern, especially for lithography in the extreme ultraviolet (EUV) regime. Large-scale screening and performance-based down-selection is currently underway to identify resist platforms that can support shrinking feature sizes. Resist screening efforts, however, are hampered by the absence of reliable resolution metrics that can objectively quantify resist resolution in a high-throughput fashion. Here we examine two high-throughput metrics for resist resolution determination. After summarizing their details and justifying their utility, we characterize the sensitivity of both metrics to two of the main experimental uncertainties associated with lithographic exposure tools, namely: limited focus control and limited knowledge of optical aberrations. For an implementation at EUV wavelengths, we report aberration and focus limited error bars in extracted resolution of {approx} 1.25 nm RMS for both metrics making them attractive candidates for future screening and down-selection efforts.

  16. Correcting systematic errors in high-sensitivity deuteron polarization measurements

    Energy Technology Data Exchange (ETDEWEB)

    Brantjes, N.P.M. [Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen (Netherlands); Dzordzhadze, V. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Gebel, R. [Institut fuer Kernphysik, Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Gonnella, F. [Physica Department of ' Tor Vergata' University, Rome (Italy); INFN-Sez. ' Roma tor Vergata,' Rome (Italy); Gray, F.E. [Regis University, Denver, CO 80221 (United States); Hoek, D.J. van der [Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen (Netherlands); Imig, A. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Kruithof, W.L. [Kernfysisch Versneller Instituut, University of Groningen, NL-9747AA Groningen (Netherlands); Lazarus, D.M. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Lehrach, A.; Lorentz, B. [Institut fuer Kernphysik, Juelich Center for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany); Messi, R. [Physica Department of ' Tor Vergata' University, Rome (Italy); INFN-Sez. ' Roma tor Vergata,' Rome (Italy); Moricciani, D. [INFN-Sez. ' Roma tor Vergata,' Rome (Italy); Morse, W.M. [Brookhaven National Laboratory, Upton, NY 11973 (United States); Noid, G.A. [Indiana University Cyclotron Facility, Bloomington, IN 47408 (United States); and others

    2012-02-01

    This paper reports deuteron vector and tensor beam polarization measurements taken to investigate the systematic variations due to geometric beam misalignments and high data rates. The experiments used the In-Beam Polarimeter at the KVI-Groningen and the EDDA detector at the Cooler Synchrotron COSY at Juelich. By measuring with very high statistical precision, the contributions that are second-order in the systematic errors become apparent. By calibrating the sensitivity of the polarimeter to such errors, it becomes possible to obtain information from the raw count rate values on the size of the errors and to use this information to correct the polarization measurements. During the experiment, it was possible to demonstrate that corrections were satisfactory at the level of 10{sup -5} for deliberately large errors. This may facilitate the real time observation of vector polarization changes smaller than 10{sup -6} in a search for an electric dipole moment using a storage ring.

  17. A rugged high-throughput analytical approach for the determination and quantification of multiple mycotoxins in complex feed matrices.

    Science.gov (United States)

    Dzuman, Zbynek; Zachariasova, Milena; Lacina, Ondrej; Veprikova, Zdenka; Slavikova, Petra; Hajslova, Jana

    2014-04-01

    We have developed and optimized high throughput method for reliable detection and quantification of 56 Fusarium, Alternaria, Penicillium, Aspergillus and Claviceps mycotoxins in a wide range of animal feed samples represented by cereals, complex compound feeds, extracted oilcakes, fermented silages, malt sprouts or dried distillers' grains with solubles (DDGS). From three tested extraction approaches (acetonitrile, acetonitrile/water, and QuEChERS), the QuEChERS-based method (Quick, Easy, Cheap, Effective, Rugged and Safe) was selected as the best in terms of analytes recoveries and low matrix effects. For separation and detection of target mycotoxins, method based on ultra-high performance liquid chromatography coupled with sensitive tandem mass spectrometry (U-HPLC-MS/MS) was employed. With regards to a high complexity of most of investigated feed samples, optimization of extraction/purification process was needed in the first phase to keep the method as rugged as possible. A special attention was paid to the pH of extraction solvents, especially with regard to the pH-sensitive silages. Additionally, purification of the acetonitrile extract by dispersive solid phase clean-up was assessed. Significant elimination of lipidic compounds was observed when using C18 silica sorbent. Matrix co-extracts were characterized by ultra-high performance liquid chromatography coupled with ultra-high resolution mass spectrometry (U-HPLC-HRMS). Large variability of matrix effects depending on the nature of examined feed was demonstrated in depth on a broad set of samples. Simple and unbiased strategies for their compensation were suggested.

  18. Sensitive and high-fidelity electrochemical immunoassay using carbon nanotubes coated with enzymes and magnetic nanoparticles.

    Science.gov (United States)

    Piao, Yunxian; Jin, Zongwen; Lee, Dohoon; Lee, Hye-Jin; Na, Hyon-Bin; Hyeon, Taeghwan; Oh, Min-Kyu; Kim, Jungbae; Kim, Hak-Sung

    2011-03-15

    We demonstrate a highly sensitive electrochemical immunosensor based on the combined use of substrate recycling and carbon nanotubes (CNTs) coated with tyrosinase (TYR) and magnetic nanoparticles (MNP). Both TYR and MNP were immobilized on the surface of CNTs by covalent attachment, followed by additional cross-linking via glutaraldehyde treatment to construct multi-layered cross-linked TYR-MNP aggregates (M-EC-CNT). Magnetically capturable, highly active and stable M-EC-CNT were further conjugated with primary antibody against a target analyte of hIgG, and used for a sandwich-type immunoassay with a secondary antibody conjugated with alkaline phosphatase (ALP). In the presence of a target analyte, a sensing assembly of M-EC-CNT and ALP-conjugated antibody was attracted onto a gold electrode using a magnet. On an electrode, ALP-catalyzed hydrolysis of phenyl phosphate generated phenol, and successive TYR-catalyzed oxidation of phenol produced electrochemically measurable o-quinone that was converted to catechol in a scheme of substrate recycling. Combination of highly active M-EC-CNT and substrate recycling for the detection of hIgG resulted in a sensitivity of 27.6 nA ng(-1) mL(-1) and a detection limit of 0.19 ng mL(-1) (1.2 pM), respectively, representing better performance than any other electrochemical immunosensors relying on the substrate recycling with the TYR-ALP combination. The present immunosensing system also displayed a long-term stability by showing a negligible loss of electrochemical detection signal even after reagents were stored in an aqueous buffer at 4°C for more than 6 months.

  19. High Sensitivity MEMS Strain Sensor: Design and Simulation

    Directory of Open Access Journals (Sweden)

    Edmond Lou

    2008-04-01

    Full Text Available In this article, we report on the new design of a miniaturized strain microsensor. The proposed sensor utilizes the piezoresistive properties of doped single crystal silicon. Employing the Micro Electro Mechanical Systems (MEMS technology, high sensor sensitivities and resolutions have been achieved. The current sensor design employs different levels of signal amplifications. These amplifications include geometric, material and electronic levels. The sensor and the electronic circuits can be integrated on a single chip, and packaged as a small functional unit. The sensor converts input strain to resistance change, which can be transformed to bridge imbalance voltage. An analog output that demonstrates high sensitivity (0.03mV/me, high absolute resolution (1μe and low power consumption (100μA with a maximum range of ±4000μe has been reported. These performance characteristics have been achieved with high signal stability over a wide temperature range (±50oC, which introduces the proposed MEMS strain sensor as a strong candidate for wireless strain sensing applications under harsh environmental conditions. Moreover, this sensor has been designed, verified and can be easily modified to measure other values such as force, torque…etc. In this work, the sensor design is achieved using Finite Element Method (FEM with the application of the piezoresistivity theory. This design process and the microfabrication process flow to prototype the design have been presented.

  20. Comparison of analytical and Monte Carlo calculations of multi-photon effects in bremsstrahlung emission by high-energy electrons

    DEFF Research Database (Denmark)

    Mangiarotti, Alessio; Sona, Pietro; Ballestrero, Sergio

    2012-01-01

    Approximate analytical calculations of multi-photon effects in the spectrum of total radiated energy by high-energy electrons crossing thin targets are compared to the results of Monte Carlo type simulations. The limits of validity of the analytical expressions found in the literature are establi...

  1. Comparison of analytical and Monte Carlo calculations of multi-photon effects in bremsstrahlung emission by high-energy electrons

    Energy Technology Data Exchange (ETDEWEB)

    Mangiarotti, A. [Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Coimbra (Portugal); Departamento de Fisica, Faculdade de Ciencias e Tecnologia da Universidade de Coimbra, Coimbra (Portugal); Sona, P., E-mail: pietro.sona@fi.infn.it [Dipartimento di Fisica e Astronomia, Universita degli Studi di Firenze, Polo Scientifico, Via G. Sansone 1, 50019 Sesto Fiorentino (Italy); INFN, Sezione di Firenze (Italy); Ballestrero, S. [Department of Physics University of Johannesburg, Johannesburg (South Africa); CERN PH/ADT, Geneve (Switzerland); Uggerhoj, U.I.; Andersen, K.K. [Department of Physics and Astronomy, University of Aarhus, Aarhus (Denmark)

    2012-10-15

    Approximate analytical calculations of multi-photon effects in the spectrum of total radiated energy by high-energy electrons crossing thin targets are compared to the results of Monte Carlo type simulations. The limits of validity of the analytical expressions found in the literature are established. The separate contributions to spectral distortion of electromagnetic processes other than bremsstrahlung are also studied in detail.

  2. PANTHER. Pattern ANalytics To support High-performance Exploitation and Reasoning.

    Energy Technology Data Exchange (ETDEWEB)

    Czuchlewski, Kristina Rodriguez [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Hart, William E. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Sandia has approached the analysis of big datasets with an integrated methodology that uses computer science, image processing, and human factors to exploit critical patterns and relationships in large datasets despite the variety and rapidity of information. The work is part of a three-year LDRD Grand Challenge called PANTHER (Pattern ANalytics To support High-performance Exploitation and Reasoning). To maximize data analysis capability, Sandia pursued scientific advances across three key technical domains: (1) geospatial-temporal feature extraction via image segmentation and classification; (2) geospatial-temporal analysis capabilities tailored to identify and process new signatures more efficiently; and (3) domain- relevant models of human perception and cognition informing the design of analytic systems. Our integrated results include advances in geographical information systems (GIS) in which we discover activity patterns in noisy, spatial-temporal datasets using geospatial-temporal semantic graphs. We employed computational geometry and machine learning to allow us to extract and predict spatial-temporal patterns and outliers from large aircraft and maritime trajectory datasets. We automatically extracted static and ephemeral features from real, noisy synthetic aperture radar imagery for ingestion into a geospatial-temporal semantic graph. We worked with analysts and investigated analytic workflows to (1) determine how experiential knowledge evolves and is deployed in high-demand, high-throughput visual search workflows, and (2) better understand visual search performance and attention. Through PANTHER, Sandia's fundamental rethinking of key aspects of geospatial data analysis permits the extraction of much richer information from large amounts of data. The project results enable analysts to examine mountains of historical and current data that would otherwise go untouched, while also gaining meaningful, measurable, and defensible insights into

  3. High-performance thin layer chromatography: A powerful analytical technique in pharmaceutical drug discovery

    Science.gov (United States)

    Attimarad, Mahesh; Ahmed, K. K. Mueen; Aldhubaib, Bandar E.; Harsha, Sree

    2011-01-01

    Analysis of pharmaceutical and natural compounds and newer drugs is commonly used in all the stages of drug discovery and development process. High-performance thin layer chromatography is one of the sophisticated instrumental techniques based on the full capabilities of thin layer chromatography. The advantages of automation, scanning, full optimization, selective detection principle, minimum sample preparation, hyphenation, and so on enable it to be a powerful analytical tool for chromatographic information of complex mixtures of pharmaceuticals, natural products, clinical samples, food stuffs, and so on. PMID:23781433

  4. Highly accurate analytical energy of a two-dimensional exciton in a constant magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Hoang, Ngoc-Tram D. [Department of Physics, Ho Chi Minh City University of Pedagogy 280, An Duong Vuong Street, District 5, Ho Chi Minh City (Viet Nam); Nguyen, Duy-Anh P. [Department of Natural Science, Thu Dau Mot University, 6, Tran Van On Street, Thu Dau Mot City, Binh Duong Province (Viet Nam); Hoang, Van-Hung [Department of Physics, Ho Chi Minh City University of Pedagogy 280, An Duong Vuong Street, District 5, Ho Chi Minh City (Viet Nam); Le, Van-Hoang, E-mail: levanhoang@tdt.edu.vn [Atomic Molecular and Optical Physics Research Group, Ton Duc Thang University, 19 Nguyen Huu Tho Street, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam); Faculty of Applied Sciences, Ton Duc Thang University, 19 Nguyen Huu Tho Street, Tan Phong Ward, District 7, Ho Chi Minh City (Viet Nam)

    2016-08-15

    Explicit expressions are given for analytically describing the dependence of the energy of a two-dimensional exciton on magnetic field intensity. These expressions are highly accurate with the precision of up to three decimal places for the whole range of the magnetic field intensity. The results are shown for the ground state and some excited states; moreover, we have all formulae to obtain similar expressions of any excited state. Analysis of numerical results shows that the precision of three decimal places is maintained for the excited states with the principal quantum number of up to n=100.

  5. In-line microfluidic integration of photonic crystal fibres as a highly sensitive refractometer.

    Science.gov (United States)

    Wu, Chuang; Tse, Ming-Leung Vincent; Liu, Zhengyong; Guan, Bai-Ou; Zhang, A Ping; Lu, Chao; Tam, Hwa-Yaw

    2014-11-07

    Photonic crystal fibres appear to be an ideal platform for the realisation of novel optofluidic devices and sensors due to their waveguide nature and microstructured architecture. In this paper, we present the fabrication and characterisation of an in-line photonic crystal fibre microfluidic refractometer enabled by a C-shaped fibre. The C-shaped fibre spliced in-between the photonic crystal fibre and the single-mode fibre allows simultaneous in-line optical signal delivery and analyte fluid feeding. Through an arc discharge pre-treatment technique, we successfully achieve selective exploitation of only the central two channels of the photonic crystal fibre for microfluidic sensing. After constructing a Sagnac interferometer, a highly sensitive refractometer with a sensitivity of 8699 nm per RIU was achieved experimentally; this agrees very well with the theoretical value of 8675 nm per RIU. As a demonstration for label-free optical sensing application, the refractometer was used to measure the concentration of NaCl solution with a sensitivity of 15.08 nm/(1 wt%) and a detection limit of 2.3 × 10(-3) wt% (23 ppm).

  6. Study on low-phase-noise optoelectronic oscillator and high-sensitivity phase noise measurement system.

    Science.gov (United States)

    Hong, Jun; Liu, An-min; Guo, Jian

    2013-08-01

    An analytic model for an injection-locked dual-loop optoelectronic oscillator (OEO) is proposed and verified by experiments in this paper. Based on this theoretical model, the effect of injection power on the single-sideband phase noise of the OEO is analyzed, and results suggest that moderate injection is one key factor for a balance between phase noise and spur for OEO. In order to measure superlow phase noise of OEOs, a cross-correlation measurement system based on the fiber delay line is built, in which high linear photodetector and low-phase-noise amplifier are used to improve systematic sensitivity. The cross-correlation measurement system is validated by experiments, and its noise floor for the X band is about -130 dBc/Hz at 1 kHz and -168 dBc/Hz at 10 kHz after a cross correlation of 200 times.

  7. Highly sensitive flow-injection chemiluminescence determination of pyrogallol compounds

    Science.gov (United States)

    Kanwal, Shamsa; Fu, Xiaohong; Su, Xingguang

    2009-12-01

    A highly sensitive flow-injection chemiluminescent method for the direct determination of pyrogallol compounds has been developed. Proposed method is based on the enhanced effect of pyrogallol compounds on the chemiluminescence signals of KMnO 4-H 2O 2 system in slightly alkaline medium. Three important pyrogallol compounds, pyrogallic acid, gallic acid and tannic acid, have been detected by this method, and the possible mechanism of the CL reaction is also discussed. The proposed method is simple, convenient, rapid (60 samples h -1), and sensitive, has a linear range of 8 × 10 -10 mol L -1 to 1 × 10 -5 mol L -1, for pyrogallic acid, with a detection limit of 6 × 10 -11 mol L -1, 4 × 10 -8 mol L -1 to 5 × 10 -3 mol L -1 for gallic acid with a detection limit of 9 × 10 -10 mol L -1, and 8 × 10 -8 mol L -1 to 5 × 10 -2 mol L -1 for tannic acid, with a detection limit of 2 × 10 -9 mol L -1, respectively. The relative standard deviation (RSD, n = 15) was 0.8, 1.1 and 1.3% for 5 × 10 -6 mol L -1 pyrogallic acid, gallic acid and tannic acid, respectively. The proposed method was successfully applied to the determination of pyrogallol compounds in tea and coffee samples.

  8. PlanetPol: A Very High Sensitivity Polarimeter

    Science.gov (United States)

    Hough, J. H.; Lucas, P. W.; Bailey, J. A.; Tamura, M.; Hirst, E.; Harrison, D.; Bartholomew-Biggs, M.

    2006-09-01

    We have built and used on several occasions an optical broadband stellar polarimeter, PlanetPol, which employs photoelastic modulators and avalanche photodiodes and achieves a photon-noise-limited sensitivity of at least 1 in 106 in fractional polarization. Observations of a number of polarized standards taken from the literature show that the accuracy of polarization measurements is ~1%. We have developed a method for accurately measuring the polarization of altitude-azimuth mounted telescopes by observing bright nearby stars at different parallactic angles, and we find that the on-axis polarization of the William Herschel Telescope is typically ~15 × 10-6, measured with an accuracy of a few parts in 107. The nearby stars (distance less than 32 pc) are found to have very low polarizations, typically a few ×10-6, indicating that very little interstellar polarization is produced close to the Sun and that their intrinsic polarization is also low. Although the polarimeter can be used for a wide range of astronomy, the very high sensitivity was set by the goal of detecting the polarization signature of unresolved extrasolar planets.

  9. Kinetics of Highly Sensitive Troponin T after Cardiac Surgery

    Directory of Open Access Journals (Sweden)

    Amr S. Omar

    2015-01-01

    Full Text Available Perioperative myocardial infarction (PMI confers a considerable risk in cardiac surgery settings; finding the ideal biomarker seems to be an ideal goal. Our aim was to assess the diagnostic accuracy of highly sensitive troponin T (hsTnT in cardiac surgery settings and to define a diagnostic level for PMI diagnosis. This was a single-center prospective observational study analyzing data from all patients who underwent cardiac surgeries. The primary outcome was the diagnosis of PMI through a specific level. The secondary outcome measures were the lengths of mechanical ventilation (LOV, stay in the intensive care unit (LOSICU, and hospitalization. Based on the third universal definition of PMI, patients were divided into two groups: no PMI (Group I and PMI (Group II. Data from 413 patients were analyzed. Nine patients fulfilled the diagnostic criteria of PMI, while 41 patients were identified with a 5-fold increase in their CK-MB (≥120 U/L. Using ROC analysis, a hsTnT level of 3,466 ng/L or above showed 90% sensitivity and 90% specificity for the diagnosis of PMI. Secondary outcome measures in patients with PMI were significantly prolonged. In conclusion, the hsTnT levels detected here paralleled those of CK-MB and a cut-off level of 3466 ng/L could be diagnostic of PMI.

  10. Development of a New, High Sensitivity 2000 kg Mechanical Balance.

    Science.gov (United States)

    Wang, Jian

    2017-04-13

    Mass measurement of more than 500 kg on an electronic mass comparator has no better repeatability and linearity of measurement for meeting the calibration requirement of over class F1 weights from pharmacy and power generation plants. For this purpose, a new 2000 kg mechanical balance was developed by the National Institute of Metrology (NIM). The advantages of measurement of more than 500 kg on a new 2000 kg mechanical balance are introduced in the paper. In order to obtain high measurement uncertainty, four vertical forces of two sides of beam are measured and used as reference for adjustment of the beam position. Laser displacement sensors in the indication system are more effective for decreasing reading errors caused by human vision. To improve the repeatability and sensitivity of the equipment, a synchronous lifting control is designed for synchronously lifting the beam ends along the vertical direction. A counterweight selection system is developed to get any combination of weights in a limited space. The sensitivity of the new mechanical balance for 2000 kg is more than 1.7 parts in 10(-4) rad/g. The extended uncertainties for the mechanical balance of 500 kg, 1000 kg and 2000 kg are 0.47 g, 1.8 g and 3.5 g respectively.

  11. New application of superconductors: High sensitivity cryogenic light detectors

    Science.gov (United States)

    Cardani, L.; Bellini, F.; Casali, N.; Castellano, M. G.; Colantoni, I.; Coppolecchia, A.; Cosmelli, C.; Cruciani, A.; D'Addabbo, A.; Di Domizio, S.; Martinez, M.; Tomei, C.; Vignati, M.

    2017-02-01

    In this paper we describe the current status of the CALDER project, which is developing ultra-sensitive light detectors based on superconductors for cryogenic applications. When we apply an AC current to a superconductor, the Cooper pairs oscillate and acquire kinetic inductance, that can be measured by inserting the superconductor in a LC circuit with high merit factor. Interactions in the superconductor can break the Cooper pairs, causing sizable variations in the kinetic inductance and, thus, in the response of the LC circuit. The continuous monitoring of the amplitude and frequency modulation allows to reconstruct the incident energy with excellent sensitivity. This concept is at the basis of Kinetic Inductance Detectors (KIDs) that are characterized by natural aptitude to multiplexed read-out (several sensors can be tuned to different resonant frequencies and coupled to the same line), resolution of few eV, stable behavior over a wide temperature range, and ease in fabrication. We present the results obtained by the CALDER collaboration with 2×2 cm2 substrates sampled by 1 or 4 Aluminum KIDs. We show that the performances of the first prototypes are already competitive with those of other commonly used light detectors, and we discuss the strategies for a further improvement.

  12. A highly sensitive fiber Bragg grating diaphragm pressure transducer

    Science.gov (United States)

    Allwood, Gary; Wild, Graham; Lubansky, Alex; Hinckley, Steven

    2015-10-01

    In this work, a novel diaphragm based pressure transducer with high sensitivity is described, including the physical design structure, in-depth analysis of optical response to changes in pressure, and a discussion of practical implementation and limitations. A flat circular rubber membrane bonded to a cylinder forms the body of the transducer. A fiber Bragg grating bonded to the center of the diaphragm structure enables the fractional change in pressure to be determined by analyzing the change in Bragg wavelength of the reflected spectra. Extensive evaluation of the physical properties and optical characteristics of the transducer has been performed through experimentation, and modeling using small deformation theory. The results show the transducer has a sensitivity of 0.116 nm/kPa, across a range of 15 kPa. Ultra-low cost interrogation of the optical signal was achieved through the use of an optically mismatched Bragg grating acting as an edge filter to convert the spectral change into an intensity change. A numerical model of the intensity based interrogation was implemented in order to validate the experimental results. Utilizing this interrogation technique and housing both the sensing and reference Bragg gratings within the main body of the transducer means it is effectively temperature insensitive and easily connected to electronic systems.

  13. Sensitivity of once-shocked, weathered high explosives

    Energy Technology Data Exchange (ETDEWEB)

    Williams, K.L.; Harris, B.W.

    1998-07-01

    Effects caused by stimulating once-shocked, weathered high explosives (OSW-HE) are investigated. The sensitivity of OSW-HE to mechanical stimuli was determined using standard industry tests. Some initial results are given. Pieces of OSW-HE were collected from active and inactive firing sites and from an area surrounding a drop tower at Los Alamos where skid and spigot tests were done. Samples evaluated were cast explosives or plastic bonded explosive (PBX) formulations containing cyclotrimethylenetrinitramine (RDX), cyclotetramethylene tetranitramine (HMX), 2,4,6-trinitrotoluene (TNT), mock or inert HE [tris(beta-chloroethyl)phosphate (CEF)], barium nitrate, cyanuric acid, talc, and Kel-F. Once-shocked, weathered LX-10 Livermore explosive [HMX/Viton A, (95/5 wt %)], PBX 9011 [HMX/Estane, (90/10 wt %)], PBX 9404 [HMX/nitrocellulose, tris(beta-chloroethyl) phosphate, (94/3/3 wt %)], Composition B or cyclotol (TNT/RDX explosives), and PBX 9007 (90% RDX, 9.1% styrene, 0.5% dioctyl phthalate, and 0.45 resin) were subjected to the hammer test, the drop-weight impact sensitivity test, differential thermal analysis (DTA), the spark test, the Henkin`s critical temperature test, and the flame test. Samples were subjected to remote, wet cutting and drilling; remote, liquid-nitrogen-cooled grinding and crushing; and scanning electron microscope (SEM) surface analyses for morphological changes.

  14. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.

    Energy Technology Data Exchange (ETDEWEB)

    Anstey, Mitchell R.; Fruetel, Julia A.; Foster, Michael E.; Hayden, Carl C.; Buckley, Heather L.; Arnold, John

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  15. Laser processes and analytics for high power 3D battery materials

    Science.gov (United States)

    Pfleging, W.; Zheng, Y.; Mangang, M.; Bruns, M.; Smyrek, P.

    2016-03-01

    Laser processes for cutting, modification and structuring of energy storage materials such as electrodes, separator materials and current collectors have a great potential in order to minimize the fabrication costs and to increase the performance and operational lifetime of high power lithium-ion-batteries applicable for stand-alone electric energy storage devices and electric vehicles. Laser direct patterning of battery materials enable a rather new technical approach in order to adjust 3D surface architectures and porosity of composite electrode materials such as LiCoO2, LiMn2O4, LiFePO4, Li(NiMnCo)O2, and Silicon. The architecture design, the increase of active surface area, and the porosity of electrodes or separator layers can be controlled by laser processes and it was shown that a huge impact on electrolyte wetting, lithium-ion diffusion kinetics, cell life-time and cycling stability can be achieved. In general, the ultrafast laser processing can be used for precise surface texturing of battery materials. Nevertheless, regarding cost-efficient production also nanosecond laser material processing can be successfully applied for selected types of energy storage materials. A new concept for an advanced battery manufacturing including laser materials processing is presented. For developing an optimized 3D architecture for high power composite thick film electrodes electrochemical analytics and post mortem analytics using laser-induced breakdown spectroscopy were performed. Based on mapping of lithium in composite electrodes, an analytical approach for studying chemical degradation in structured and unstructured lithium-ion batteries will be presented.

  16. Towards an analytical theory of the third-body problem for highly elliptical orbits

    CERN Document Server

    Lion, Guillaume; Deleflie, Florent

    2016-01-01

    When dealing with satellites orbiting a central body on a highly elliptical orbit, it is necessary to consider the effect of gravitational perturbations due to external bodies. Indeed, these perturbations can become very important as soon as the altitude of the satellite becomes high, which is the case around the apocentre of this type of orbit. For several reasons, the traditional tools of celestial mechanics are not well adapted to the particular dynamic of highly elliptical orbits. On the one hand, analytical solutions are quite generally expanded into power series of the eccentricity and therefore limited to quasi-circular orbits [17, 25]. On the other hand, the time-dependency due to the motion of the third-body is often neglected. We propose several tools to overcome these limitations. Firstly, we have expanded the disturbing function into a finite polynomial using Fourier expansions of elliptic motion functions in multiple of the satellite's eccentric anomaly (instead of the mean anomaly) and involving...

  17. Project Title: Radiochemical Analysis by High Sensitivity Dual-Optic Micro X-ray Fluorescence

    Energy Technology Data Exchange (ETDEWEB)

    Havrilla, George J.; Gao, Ning

    2002-06-01

    A novel dual-optic micro X-ray fluorescence instrument will be developed to do radiochemical analysis of high-level radioactive wastes at DOE sites such as Savannah River Site and Hanford. This concept incorporates new X-ray optical elements such as monolithic polycapillaries and double bent crystals, which focus X-rays. The polycapillary optic can be used to focus X-rays emitted by the X-ray tube thereby increasing the X-ray flux on the sample over 1000 times. Polycapillaries will also be used to collect the X-rays from the excitation site and screen the radiation background from the radioactive species in the specimen. This dual-optic approach significantly reduces the background and increases the analyte signal thereby increasing the sensitivity of the analysis. A doubly bent crystal used as the focusing optic produces focused monochromatic X-ray excitation, which eliminates the bremsstrahlung background from the X-ray source. The coupling of the doubly bent crystal for monochromatic excitation with a polycapillary for signal collection can effectively eliminate the noise background and radiation background from the specimen. The integration of these X-ray optics increases the signal-to-noise and thereby increases the sensitivity of the analysis for low-level analytes. This work will address a key need for radiochemical analysis of high-level waste using a non-destructive, multi-element, and rapid method in a radiation environment. There is significant potential that this instrumentation could be capable of on-line analysis for process waste stream characterization at DOE sites.

  18. Analytical Method Validation of High-Performance Liquid Chromatography and Stability-Indicating Study of Medroxyprogesterone Acetate Intravaginal Sponges.

    Science.gov (United States)

    Batrawi, Nidal; Wahdan, Shorouq; Abualhasan, Murad

    2017-01-01

    Medroxyprogesterone acetate is widely used in veterinary medicine as intravaginal dosage for the synchronization of breeding cycle in ewes and goats. The main goal of this study was to develop reverse-phase high-performance liquid chromatography method for the quantification of medroxyprogesterone acetate in veterinary vaginal sponges. A single high-performance liquid chromatography/UV isocratic run was used for the analytical assay of the active ingredient medroxyprogesterone. The chromatographic system consisted of a reverse-phase C18 column as the stationary phase and a mixture of 60% acetonitrile and 40% potassium dihydrogen phosphate buffer as the mobile phase; the pH was adjusted to 5.6. The method was validated according to the International Council for Harmonisation (ICH) guidelines. Forced degradation studies were also performed to evaluate the stability-indicating properties and specificity of the method. Medroxyprogesterone was eluted at 5.9 minutes. The linearity of the method was confirmed in the range of 0.0576 to 0.1134 mg/mL (R(2) > 0.999). The limit of quantification was shown to be 3.9 µg/mL. Precision and accuracy ranges were found to be %RSD <0.2 and 98% to 102%, respectively. Medroxyprogesterone capacity factor value of 2.1, tailing factor value of 1.03, and resolution value of 3.9 were obtained in accordance with ICH guidelines. Based on the obtained results, a rapid, precise, accurate, sensitive, and cost-effective analysis procedure was proposed for quantitative determination of medroxyprogesterone in vaginal sponges. This analytical method is the only available method to analyse medroxyprogesterone in veterinary intravaginal dosage form.

  19. Analytical Method Validation of High-Performance Liquid Chromatography and Stability-Indicating Study of Medroxyprogesterone Acetate Intravaginal Sponges

    Directory of Open Access Journals (Sweden)

    Nidal Batrawi

    2017-02-01

    Full Text Available Medroxyprogesterone acetate is widely used in veterinary medicine as intravaginal dosage for the synchronization of breeding cycle in ewes and goats. The main goal of this study was to develop reverse-phase high-performance liquid chromatography method for the quantification of medroxyprogesterone acetate in veterinary vaginal sponges. A single high-performance liquid chromatography/UV isocratic run was used for the analytical assay of the active ingredient medroxyprogesterone. The chromatographic system consisted of a reverse-phase C18 column as the stationary phase and a mixture of 60% acetonitrile and 40% potassium dihydrogen phosphate buffer as the mobile phase; the pH was adjusted to 5.6. The method was validated according to the International Council for Harmonisation (ICH guidelines. Forced degradation studies were also performed to evaluate the stability-indicating properties and specificity of the method. Medroxyprogesterone was eluted at 5.9 minutes. The linearity of the method was confirmed in the range of 0.0576 to 0.1134 mg/mL ( R 2 > 0.999. The limit of quantification was shown to be 3.9 µg/mL. Precision and accuracy ranges were found to be %RSD <0.2 and 98% to 102%, respectively. Medroxyprogesterone capacity factor value of 2.1, tailing factor value of 1.03, and resolution value of 3.9 were obtained in accordance with ICH guidelines. Based on the obtained results, a rapid, precise, accurate, sensitive, and cost-effective analysis procedure was proposed for quantitative determination of medroxyprogesterone in vaginal sponges. This analytical method is the only available method to analyse medroxyprogesterone in veterinary intravaginal dosage form.

  20. The sensitivity of past and near-future lunar radio experiments to ultra-high-energy cosmic rays and neutrinos

    CERN Document Server

    Bray, Justin

    2016-01-01

    Various experiments have been conducted to search for the radio emission from ultra-high-energy particles interacting in the lunar regolith. Although they have not yielded any detections, they have been successful in establishing upper limits on the flux of these particles. I present a review of these experiments in which I re-evaluate their sensitivity to radio pulses, accounting for effects which were neglected in the original reports, and compare them with prospective near-future experiments. In several cases, I find that past experiments were substantially less sensitive than previously believed. I apply existing analytic models to determine the resulting limits on the fluxes of ultra-high-energy neutrinos and cosmic rays. In the latter case, I amend the model to accurately reflect the fraction of the primary particle energy which manifests in the resulting particle cascade, resulting in a substantial improvement in the estimated sensitivity to cosmic rays. Although these models are in need of further ref...

  1. Tunable diameter electrostatically formed nanowire for high sensitivity gas sensing

    Institute of Scientific and Technical Information of China (English)

    Alex Henning; Nandhini Swaminathan; Andrey Godkin; Gil Shalev; Iddo Amit; Yossi Rosenwaks

    2015-01-01

    We report on an electrostatically formed nanowire (EFN)-based sensor with tunable diameters in the range of 16 nm to 46 nm and demonstrate an EFN- based field-effect transistor as a highly sensitive and robust room temperature gas sensor. The device was carefully designed and fabricated using standard integrated processing to achieve the 16 nm EFN that can be used for sensing without any need for surface modification. The effective diameter for the EFN was determined using Kelvin probe force microscopy accompanied by three- dimensional electrostatic simulations. We show that the EFN transistor is capable of detecting 100 parts per million of ethanol gas with bare SiO2.

  2. Magnetic probe array with high sensitivity for fluctuating field.

    Science.gov (United States)

    Kanamaru, Yuki; Gota, Hiroshi; Fujimoto, Kayoko; Ikeyama, Taeko; Asai, Tomohiko; Takahashi, Tsutomu; Nogi, Yasuyuki

    2007-03-01

    A magnetic probe array is constructed to measure precisely the spatial structure of a small fluctuating field included in a strong confinement field that varies with time. To exclude the effect of the confinement field, the magnetic probes consisting of figure-eight-wound coils are prepared. The spatial structure of the fluctuating field is obtained from a Fourier analysis of the probe signal. It is found that the probe array is more sensitive to the fluctuating field with a high mode number than that with a low mode number. An experimental demonstration of the present method is attempted using a field-reversed configuration plasma, where the fluctuating field with 0.1% of the confinement field is successfully detected.

  3. High Efficiency of Dye-Sensitized Solar Cells

    Institute of Scientific and Technical Information of China (English)

    Liyuan Han

    2005-01-01

    @@ 1Introduction Much attention has been paid to the development of dye-sensitized solar cells (DSCs) during the past decade. In general, a DSC comprises a nanocrystalline titanium dioxide (TiO2) electrode modified with a dye fabricated on a transparent conducting oxide (TCO), a platinum (Pt) counter electrode, and an electrolyte solution with a dissolved iodide ion/tri-iodide ion redox couple between the electrodes. Although a DSC using black dye with high efficiency of 10.4%, which was measured by NREL(U. S. A. ), was reported by Graetzel et al. [1], the efficiency of DSCs should be further improved for practical use in comparison with silicon solar cells.

  4. High efficiency solid-state sensitized heterojunction photovoltaic device

    KAUST Repository

    Wang, Mingkui

    2010-06-01

    The high molar extinction coefficient heteroleptic ruthenium dye, NaRu(4,4′-bis(5-(hexylthio)thiophen-2-yl)-2,2′-bipyridine) (4-carboxylic acid-4′-carboxylate-2,2′-bipyridine) (NCS) 2, exhibits certified 5% electric power conversion efficiency at AM 1.5 solar irradiation (100 mW cm-2) in a solid-state dye-sensitized solar cell using 2,2′,7,7′-tetrakis-(N,N-di-pmethoxyphenylamine)-9, 9′-spirobifluorene (spiro-MeOTAD) as the organic hole-transporting material. This demonstration elucidates a class of photovoltaic devices with potential for low-cost power generation. © 2010 Elsevier Ltd. All rights reserved.

  5. High sensitivity moiré interferometry with compact achromatic interferometry

    Science.gov (United States)

    Czarnek, Robert

    Experimental observations and measurements are the sources of information essential for correct development of mathematical models of real structural materials. Moiré interferometry offers high sensitivity in full-field measurements of in-plane displacements on the surface of a specimen. Although it is a powerful method in experimental stress analysis, it has some shortcomings. One is that existing systems require highly coherent light. The only sufficient source of light for this application is a long cavity laser, which is relatively expensive and at best cumbersome. Another shortcoming is that measurements must be performed in a vibration-free environment, such as that found on a holographic table. These requirements limit the use of existing moiré interferometers to a holographic laboratory. In this paper a modified concept of compensation is presented, which permits the use of a chromatic source of light in a compact moiré system. The compensator provides order in the angles of incident light for each separate wavelength, so that the virtual reference grating created by each wavelength in a continuous spectrum is identical in frequency and spatial position. The result is a virtual reference grating that behaves exactly like that created in coherent light. With this development the use of a laser diode, which is a non-coherent light source of tiny dimensions, becomes practical. The special configuration of the optics that create the virtual grating allows its synchronization with the specimen grating and leads to an interferometer design that is relatively insensitive to the vibrations found in a mechanical testing laboratory. Sensitivity to relative motion is analyzed theoretically. This development provides the oppurtunity to apply moiré interferometry to solid mechanics problems that cannot be studied in an optics laboratory. Experimental verification of the optical concepts is provided. A compact moiré interferometer based on the presented idea was

  6. Semi-analytical method for calculating aeroelastic effect of profiled rod flying at high velocity

    Directory of Open Access Journals (Sweden)

    Hui-jun Ning

    2015-03-01

    Full Text Available The key technique of a kinetic energy rod (KER warhead is to control the flight attitude of rods. The rods are usually designed to different shapes. A new conceptual KER named profiled rod which has large L/D ratio is described in this paper. The elastic dynamic equations of this profiled rod flying at high velocity after detonation are set up on the basis of Euler-Bernoulli beam, and the aeroelastic deformation of profiled rod is calculated by semi-analytical method for calculating the vibration characteristics of variable cross-section beam. In addition, the aeroelastic deformation of the undeformed profiled rod and the aeroelastic deformation of deformed profiled rod which is caused by the detonation of explosive are simulated by computational fluid dynamic and finite element method (CFD/FEM, respectively. A satisfactory agreement of these two methods is obtained by the comparison of two methods. The results show that the semi-analytical method for calculating the vibration characteristics of variable cross-section beam is applied to analyze the aeroelastic deformation of profiled rod flying at high velocity.

  7. Analytic modeling of a high temperature thermoelectric module for wireless sensors

    Science.gov (United States)

    Köhler, J. E.; Staaf, L. G. H.; Palmqvist, A. E. C.; Enoksson, P.

    2014-11-01

    A novel high temperature thermoelectric module with thermoelectric materials never before combined in a module is currently researched. The module placement in the cooling channels of a jet engine where the cold side will be cooled by high flow cooling air (550° C) and the hot side will be at the wall (800° C). The aim of the project is to drastically reduce the length of the wires by replacing wired sensors with wireless sensors and power these (3-10mW) with thermoelectric harvesters. To optimize the design for the temperature range and the environment an analytic model was constructed. Using known models for this purpose was not possible for this project, as many of the models have too many assumptions, e.g. that the temperature gradient is relatively low, that thick electrodes with very low resistance can be used, that the heat transfer through the base plates are perfect or that the aim of the design is to maximize the efficiency. The analytical model in this paper is a combination of several known models with the aim to examine what materials to use in this specific environment to achieve the highest possible specific power (mW/g).

  8. Analytical sensitivity of staining and molecular techniques for the detection of Cryptosporidium spp. oocysts isolated from bovines in water samples: a preliminary study

    Directory of Open Access Journals (Sweden)

    A Díaz-Lee

    2015-01-01

    Full Text Available Cryptosporidium spp. is a globally distributed protozoan that causes digestive disease in different animals including humans. Excreted oocysts contaminate water and soil, constituting a public health threat. Sensitive and fast methods to detect oocysts in water samples are necessary due to the small number of oocysts present in the environment and their low infectious dose. This study compared the analytical sensitivity of two staining techniques, modified Ziehl-Neelsen and Auramine versus a nested PCR that amplifies a region of ~520bp from 18S rDNA gene, to detect Cryptosporidium spp. in water samples. Water was inoculated with oocysts using serial dilutions, and then a water filtration method was used to recover the parasite oocysts. The staining techniques had similar analytical sensitivity, detecting 8 oocysts/mL, while the nested PCR detected down to 6 oocysts/mL. In conclusion, all of these methods are effective for Cryptosporidium spp. detection in water samples, contributing to the implementation of standardized diagnostic methods for environmental water infectious agents.

  9. Scanning Auger microscopy for high lateral and depth elemental sensitivity

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, E., E-mail: eugenie.martinez@cea.fr [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Yadav, P. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Bouttemy, M. [Institut Lavoisier de Versailles, 45 av. des Etats-Unis, 78035 Versailles Cedex (France); Renault, O.; Borowik, Ł.; Bertin, F. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France); Etcheberry, A. [Institut Lavoisier de Versailles, 45 av. des Etats-Unis, 78035 Versailles Cedex (France); Chabli, A. [CEA, LETI, MINATEC Campus, 17 rue des Martyrs, 38054 Grenoble Cedex 9 (France)

    2013-12-15

    Highlights: •SAM performances and limitations are illustrated on real practical cases such as the analysis of nanowires and nanodots. •High spatial elemental resolution is shown with the analysis of reference semiconducting Al{sub 0.7}Ga{sub 0.3}As/GaAs multilayers. •High in-depth elemental resolution is also illustrated. Auger depth profiling with low energy ion beams allows revealing ultra-thin layers (∼1 nm). •Analysis of cross-sectional samples is another effective approach to obtain in-depth elemental information. -- Abstract: Scanning Auger microscopy is currently gaining interest for investigating nanostructures or thin multilayers stacks developed for nanotechnologies. New generation Auger nanoprobes combine high lateral (∼10 nm), energy (0.1%) and depth (∼2 nm) resolutions thus offering the possibility to analyze the elemental composition as well as the chemical state, at the nanometre scale. We report here on the performances and limitations on practical examples from nanotechnology research. The spatial elemental sensitivity is illustrated with the analysis of Al{sub 0.7}Ga{sub 0.3}As/GaAs heterostructures, Si nanowires and SiC nanodots. Regarding the elemental in-depth composition, two effective approaches are presented: low energy depth profiling to reveal ultra-thin layers (∼1 nm) and analysis of cross-sectional samples.

  10. Laser-engraved carbon nanotube paper for instilling high sensitivity, high stretchability, and high linearity in strain sensors

    KAUST Repository

    Xin, Yangyang

    2017-06-29

    There is an increasing demand for strain sensors with high sensitivity and high stretchability for new applications such as robotics or wearable electronics. However, for the available technologies, the sensitivity of the sensors varies widely. These sensors are also highly nonlinear, making reliable measurement challenging. Here we introduce a new family of sensors composed of a laser-engraved carbon nanotube paper embedded in an elastomer. A roll-to-roll pressing of these sensors activates a pre-defined fragmentation process, which results in a well-controlled, fragmented microstructure. Such sensors are reproducible and durable and can attain ultrahigh sensitivity and high stretchability (with a gauge factor of over 4.2 × 10(4) at 150% strain). Moreover, they can attain high linearity from 0% to 15% and from 22% to 150% strain. They are good candidates for stretchable electronic applications that require high sensitivity and linearity at large strains.

  11. Alemtuzumab induction therapy in highly sensitized kidney transplant recipients

    Institute of Scientific and Technical Information of China (English)

    L(U) Tie-ming; YANG Shun-liang; WU Wei-zhen; TAN Jian-ming

    2011-01-01

    Background Immunosuppression for immunologically high-risk kidney transplant patients usually involves antithymocyte globulin induction with triple drug maintenance therapy. Alemtuzumab, a humanized anti-CD52 antibody,was expected to be a promising induction therapy agent for kidney transplantation. However, currently no consensus is available about its efficacy and safety. This study aimed to evaluate the efficacy and safety of alemtuzumab as immune induction therapy in highly sensitized kidney transplant recipients.Methods In this prospective, open-label, randomized, controlled trial, we enrolled 23 highly immunological risk patients (panel reactive antibody >20%). They were divided into two groups: alemtuzumab group (trial group) and anti-thymocyte globulin (ATG) group (control group). Patients in the alemtuzumab group received intravenous alemtuzumab (15 mg) as a single dose before reperfusion. At the 24th hour post-operation, another dosage of alemtuzumab (15 mg) was given.The control group received a bolus of rabbit ATG (9 mg/kg), which was given 2 hours before kidney transplantation and lasted until the removal of vascular clamps when the anastomoses were completed. Maintenance immunosuppression in both groups comprised standard triple therapy consisting of tacrolimus, prednisone, and mycophenolate mofetil (MMF).Acute rejection (AR) and infection episodes were recorded, and kidney function was monitored during a 2-year follow-up.χ2 test, t test and Kaplan-Meier analysis were performed with SPSS17.0 software.Results Median follow-up was 338 days. In both the alemtuzumab group and ATG group, creatinine and blood urea nitrogen values in surviving recipients were similar (P >0.05). White blood cell counts were significantly reduced in the alemtuzumab group for the most time points up to 6 months (P <0.05). One patient receiving alemtuzumab died for acute myocardial infarction at the 65th day post-operation. Two ATG patients died for severe pulmonary

  12. Analytical modeling of trilayer graphene nanoribbon Schottky-barrier FET for high-speed switching applications.

    Science.gov (United States)

    Rahmani, Meisam; Ahmadi, Mohammad Taghi; Abadi, Hediyeh Karimi Feiz; Saeidmanesh, Mehdi; Akbari, Elnaz; Ismail, Razali

    2013-01-30

    Recent development of trilayer graphene nanoribbon Schottky-barrier field-effect transistors (FETs) will be governed by transistor electrostatics and quantum effects that impose scaling limits like those of Si metal-oxide-semiconductor field-effect transistors. The current-voltage characteristic of a Schottky-barrier FET has been studied as a function of physical parameters such as effective mass, graphene nanoribbon length, gate insulator thickness, and electrical parameters such as Schottky barrier height and applied bias voltage. In this paper, the scaling behaviors of a Schottky-barrier FET using trilayer graphene nanoribbon are studied and analytically modeled. A novel analytical method is also presented for describing a switch in a Schottky-contact double-gate trilayer graphene nanoribbon FET. In the proposed model, different stacking arrangements of trilayer graphene nanoribbon are assumed as metal and semiconductor contacts to form a Schottky transistor. Based on this assumption, an analytical model and numerical solution of the junction current-voltage are presented in which the applied bias voltage and channel length dependence characteristics are highlighted. The model is then compared with other types of transistors. The developed model can assist in comprehending experiments involving graphene nanoribbon Schottky-barrier FETs. It is demonstrated that the proposed structure exhibits negligible short-channel effects, an improved on-current, realistic threshold voltage, and opposite subthreshold slope and meets the International Technology Roadmap for Semiconductors near-term guidelines. Finally, the results showed that there is a fast transient between on-off states. In other words, the suggested model can be used as a high-speed switch where the value of subthreshold slope is small and thus leads to less power consumption.

  13. Transcriptome characteristics of filamentous fungi deduced using high-throughput analytical technologies.

    Science.gov (United States)

    Meijueiro, Martha Lucía; Santoyo, Francisco; Ramírez, Lucía; Pisabarro, Antonio G

    2014-11-01

    Transcriptomes are the complete set of genome sequences transcribed at a given time point by a given organism, organ, tissue or cell. The availability of high-throughput analytical techniques and, especially, the democratization of the use of RNA sequencing using new platforms have made it possible to transform transcriptome analysis into a common study affordable by most laboratories. In many cases, however, there is a certain level of prevention toward the use of these technologies because of the lack of knowledge about what has been done, what can be done and how high-throughput sequencing can help us solve specific scientific questions. Here, we will try to answer some initial questions about fungal transcriptome analysis, provide some examples of fungal biology questions that have been addressed using this approach and extract some general conclusions about the transcriptome structure and dynamics in fungal systems.

  14. Efficient streptavidin-functionalized nitrogen-doped graphene for the development of highly sensitive electrochemical immunosensor.

    Science.gov (United States)

    Yang, Zhanjun; Lan, Qingchun; Li, Juan; Wu, Jiajia; Tang, Yan; Hu, Xiaoya

    2017-03-15

    In this work, an efficient and universal streptavidin-functionalized nitrogen-doped graphene (NG) was for the first time proposed and used to develop a highly sensitive electrochemical immunosensor for the detection of tumor markers. Transmission electron microscopy, electrochemical impedance spectrum, static water contact measurement, and cyclic voltammetry were used to characterize the streptavidin-functionalized NG platform and immunosensor. The biofunctionalized NG showed excellent hydrophilicity, larger specific surface area, and high electrochemical activity. These properties of the platform enhanced the loading capacity of proteins, and retained the bioactivity of the immobilized proteins, and thus remarkably improved the sensitivity of the immunosensor. Using carcinoembryonic antigen (CEA) as model analyte, the proposed immunosensor demonstrated a wide linear range of 0.02-12ngmL(-1) with a low detection limit of 0.01ngmL(-1). The CEA immunosensor could be applied to detect human serum samples with satisfactory results. The streptavidin-functionalized NG material provided an universal and promising platform for the electrochemical immunosensing applications. Copyright © 2016 Elsevier B.V. All rights reserved.

  15. High-sensitivity cardiac troponin assays: answers to frequently asked questions.

    Science.gov (United States)

    Chenevier-Gobeaux, Camille; Bonnefoy-Cudraz, Éric; Charpentier, Sandrine; Dehoux, Monique; Lefevre, Guillaume; Meune, Christophe; Ray, Patrick

    2015-02-01

    Cardiac troponin (cTn) assays have quickly gained in analytical sensitivity to become what are termed 'high-sensitivity cardiac troponin' (hs-cTn) assays, bringing a flurry of dense yet incomplete literature data. The net result is that cTn assays are not yet standardized and there are still no consensus-built data on how to use and interpret cTn assay results. To address these issues, the authors take cues and clues from multiple disciplines to bring responses to frequently asked questions. In brief, the effective use of hs-cTn hinges on knowing: specific assay characteristics, particularly precision at the 99th percentile of a reference population; factors of variation at the 99th percentile value; and the high-individuality of hs-cTn assays, for which the notion of individual kinetics is more informative than straight reference to 'normal' values. The significance of patterns of change between two assay measurements has not yet been documented for every hs-cTn assay. Clinicians need to work hand-in-hand with medical biologists to better understand how to use hs-cTn assays in routine practice.

  16. High sensitivity detection of bacteria by surface plasmon resonance enhanced common path interferometry

    Science.gov (United States)

    Greef, Charles; Petropavlovskikh, Viatcheslav; Nilsen, Oyvind; Hacioglu, Bilge; Khattatov, Boris; Hall, John

    2007-04-01

    Real time monitoring of biowarfare agents (BWA) for military and civilian protection remains a high priority for homeland security and battlefield readiness. Available devices have adequate sensitivity, but the detection modules have limited periods of deployment, require frequent maintenance, employ single-use disposable components, and have limited multiplexing capability. Surface Plasmon Resonance enhanced Common Path Interferometry (SPR-CPI) is a label-free, high sensitivity biomolecular interaction measurement technology that allows multiplexed real-time measurement of biowarfare agents, including small molecules, proteins, and microbes. The technology permits continuous operation in a field-deployable detection module of an integrated BWA monitoring system. SPR-CPI measures difference in phase shift of polarized light reflected from the transducer interface caused by changes in refractive index induced by biomolecular interactions. The measurement is performed on a discrete 2-dimensional area functionalized with biomolecule capture reagents in a microarray format, allowing simultaneous measurement of up to 100 separate analytes. Output consists of simultaneous voltage measurements proportional to the phase differences resulting from the refractive index changes and is automatically processed and displayed graphically or delivered to a decision making algorithm. This enables a fully automatic field-deployable detection system capable of integration into existing modular BWA detection systems. Proof-of-concept experiments on surrogate models of anticipated BWA threats have demonstrated utility. Efforts are in progress for full development and deployment of the device.

  17. Accelerated Sensitivity Analysis in High-Dimensional Stochastic Reaction Networks.

    Science.gov (United States)

    Arampatzis, Georgios; Katsoulakis, Markos A; Pantazis, Yannis

    2015-01-01

    Existing sensitivity analysis approaches are not able to handle efficiently stochastic reaction networks with a large number of parameters and species, which are typical in the modeling and simulation of complex biochemical phenomena. In this paper, a two-step strategy for parametric sensitivity analysis for such systems is proposed, exploiting advantages and synergies between two recently proposed sensitivity analysis methodologies for stochastic dynamics. The first method performs sensitivity analysis of the stochastic dynamics by means of the Fisher Information Matrix on the underlying distribution of the trajectories; the second method is a reduced-variance, finite-difference, gradient-type sensitivity approach relying on stochastic coupling techniques for variance reduction. Here we demonstrate that these two methods can be combined and deployed together by means of a new sensitivity bound which incorporates the variance of the quantity of interest as well as the Fisher Information Matrix estimated from the first method. The first step of the proposed strategy labels sensitivities using the bound and screens out the insensitive parameters in a controlled manner. In the second step of the proposed strategy, a finite-difference method is applied only for the sensitivity estimation of the (potentially) sensitive parameters that have not been screened out in the first step. Results on an epidermal growth factor network with fifty parameters and on a protein homeostasis with eighty parameters demonstrate that the proposed strategy is able to quickly discover and discard the insensitive parameters and in the remaining potentially sensitive parameters it accurately estimates the sensitivities. The new sensitivity strategy can be several times faster than current state-of-the-art approaches that test all parameters, especially in "sloppy" systems. In particular, the computational acceleration is quantified by the ratio between the total number of parameters over the

  18. Analytical theory for highly elliptical orbits including time-dependent perturbations

    CERN Document Server

    Lion, Guillaume

    2016-01-01

    Traditional analytical theories of celestial mechanics are not well-adapted when dealing with highly elliptical orbits. On the one hand, analytical solutions are quite generally expanded into power series of the eccentricity and so limited to quasi-circular orbits. On the other hand, the time-dependency due to the motion of the third body (e.g. Moon and Sun) is almost always neglected. We propose several tools to overcome these limitations. Firstly, we have expanded the third-body disturbing function into a finite polynomial using Fourier series in multiple of the satellite's eccentric anomaly (instead of the mean anomaly) and involving Hansen-like coefficients. Next, by combining the classical Brouwer-von Zeipel procedure and the time-dependent Lie-Deprit transforms, we have performed a normalization of the expanded Hamiltonian in order to eliminate all the periodic terms. One of the benefits is that the original Brouwer solution for J2 is not modified. The main difficulty lies in the fact that the generatin...

  19. Approximate analytic method for high-apogee twelve-hour orbits of artificial Earth's satellites

    Science.gov (United States)

    Vashkovyaka, M. A.; Zaslavskii, G. S.

    2016-09-01

    We propose an approach to the study of the evolution of high-apogee twelve-hour orbits of artificial Earth's satellites. We describe parameters of the motion model used for the artificial Earth's satellite such that the principal gravitational perturbations of the Moon and Sun, nonsphericity of the Earth, and perturbations from the light pressure force are approximately taken into account. To solve the system of averaged equations describing the evolution of the orbit parameters of an artificial satellite, we use both numeric and analytic methods. To select initial parameters of the twelve-hour orbit, we assume that the path of the satellite along the surface of the Earth is stable. Results obtained by the analytic method and by the numerical integration of the evolving system are compared. For intervals of several years, we obtain estimates of oscillation periods and amplitudes for orbital elements. To verify the results and estimate the precision of the method, we use the numerical integration of rigorous (not averaged) equations of motion of the artificial satellite: they take into account forces acting on the satellite substantially more completely and precisely. The described method can be applied not only to the investigation of orbit evolutions of artificial satellites of the Earth; it can be applied to the investigation of the orbit evolution for other planets of the Solar system provided that the corresponding research problem will arise in the future and the considered special class of resonance orbits of satellites will be used for that purpose.

  20. Highly accurate analytic formulae for projectile motion subjected to quadratic drag

    Science.gov (United States)

    Turkyilmazoglu, Mustafa

    2016-05-01

    The classical phenomenon of motion of a projectile fired (thrown) into the horizon through resistive air charging a quadratic drag onto the object is revisited in this paper. No exact solution is known that describes the full physical event under such an exerted resistance force. Finding elegant analytical approximations for the most interesting engineering features of dynamical behavior of the projectile is the principal target. Within this purpose, some analytical explicit expressions are derived that accurately predict the maximum height, its arrival time as well as the flight range of the projectile at the highest ascent. The most significant property of the proposed formulas is that they are not restricted to the initial speed and firing angle of the object, nor to the drag coefficient of the medium. In combination with the available approximations in the literature, it is possible to gain information about the flight and complete the picture of a trajectory with high precision, without having to numerically simulate the full governing equations of motion.

  1. Hadoop for High-Performance Climate Analytics: Use Cases and Lessons Learned

    Science.gov (United States)

    Tamkin, Glenn

    2013-01-01

    Scientific data services are a critical aspect of the NASA Center for Climate Simulations mission (NCCS). Hadoop, via MapReduce, provides an approach to high-performance analytics that is proving to be useful to data intensive problems in climate research. It offers an analysis paradigm that uses clusters of computers and combines distributed storage of large data sets with parallel computation. The NCCS is particularly interested in the potential of Hadoop to speed up basic operations common to a wide range of analyses. In order to evaluate this potential, we prototyped a series of canonical MapReduce operations over a test suite of observational and climate simulation datasets. The initial focus was on averaging operations over arbitrary spatial and temporal extents within Modern Era Retrospective- Analysis for Research and Applications (MERRA) data. After preliminary results suggested that this approach improves efficiencies within data intensive analytic workflows, we invested in building a cyber infrastructure resource for developing a new generation of climate data analysis capabilities using Hadoop. This resource is focused on reducing the time spent in the preparation of reanalysis data used in data-model inter-comparison, a long sought goal of the climate community. This paper summarizes the related use cases and lessons learned.

  2. Hydrodynamics of Highly Viscous Flow past a Compound Particle: Analytical Solution

    Directory of Open Access Journals (Sweden)

    Longhua Zhao

    2016-11-01

    Full Text Available To investigate the translation of a compound particle in a highly viscous, incompressible fluid, we carry out an analytic study on flow past a fixed spherical compound particle. The spherical object is considered to have a rigid kernel covered with a fluid coating. The fluid within the coating has a different viscosity from that of the surrounding fluid and is immiscible with the surrounding fluid. The inertia effect is negligible for flows both inside the coating and outside the object. Thus, flows are in the Stokes regime. Taking advantage of the symmetry properties, we reduce the problem in two dimensions and derive the explicit formulae of the stream function in the polar coordinates. The no-slip boundary condition for the rigid kernel and the no interfacial mass transfer and force equilibrium conditions at fluid interfaces are considered. Two extreme cases: the uniform flow past a sphere and the uniform flow past a fluid drop, are reviewed. Then, for the fluid coating the spherical object, we derive the stream functions and investigate the flow field by the contour plots of stream functions. Contours of stream functions show circulation within the fluid coating. Additionally, we compare the drag and the terminal velocity of the object with a rigid sphere or a fluid droplet. Moreover, the extended results regarding the analytical solution for a compound particle with a rigid kernel and multiple layers of fluid coating are reported.

  3. High Sensitivity Analysis of Nanoliter Volumes of Volatile and Nonvolatile Compounds using Matrix Assisted Ionization (MAI) Mass Spectrometry

    Science.gov (United States)

    Hoang, Khoa; Pophristic, Milan; Horan, Andrew J.; Johnston, Murray V.; McEwen, Charles N.

    2016-10-01

    First results are reported using a simple, fast, and reproducible matrix-assisted ionization (MAI) sample introduction method that provides substantial improvements relative to previously published MAI methods. The sensitivity of the new MAI methods, which requires no laser, high voltage, or nebulizing gas, is comparable to those reported for MALDI-TOF and n-ESI. High resolution full acquisition mass spectra having low chemical background are acquired from low nanoliters of solution using only a few femtomoles of analyte. The limit-of-detection for angiotensin II is less than 50 amol on an Orbitrap Exactive mass spectrometer. Analysis of peptides, including a bovine serum albumin digest, and drugs, including drugs in urine without a purification step, are reported using a 1 μL zero dead volume syringe in which only the analyte solution wetting the walls of the syringe needle is used in the analysis.

  4. Highly sensitive and multiplexed platforms for allergy diagnostics

    Science.gov (United States)

    Monroe, Margo R.

    Allergy is a disorder of the immune system caused by an immune response to otherwise harmless environmental allergens. Currently 20% of the US population is allergic and 90% of pediatric patients and 60% of adult patients with asthma have allergies. These percentages have increased by 18.5% in the past decade, with predicted similar trends for the future. Here we design sensitive, multiplexed platforms to detect allergen-specific IgE using the Interferometric Reflectance Imaging Sensor (IRIS) for various clinical settings. A microarray platform for allergy diagnosis allows for testing of specific IgE sensitivity to a multitude of allergens, while requiring only small volumes of patient blood sample. However, conventional fluorescent microarray technology is limited by i) the variation of probe immobilization, which hinders the ability to make quantitative, assertive, and statistically relevant conclusions necessary in immunodiagnostics and ii) the use of fluorophore labels, which is not suitable for some clinical applications due to the tendency of fluorophores to stick to blood particulates and require daily calibration methods. This calibrated fluorescence enhancement (CaFE) method integrates the low magnification modality of IRIS with enhanced fluorescence sensing in order to directly correlate immobilized probe (major allergens) density to allergen-specific IgE in patient serum. However, this platform only operates in processed serum samples, which is not ideal for point of care testing. Thus, a high magnification modality of IRIS was adapted as an alternative allergy diagnostic platform to automatically discriminate and size single nanoparticles bound to specific IgE in unprocessed, characterized human blood and serum samples. These features make IRIS an ideal candidate for clinical and diagnostic applications, such a POC testing. The high magnification (nanoparticle counting) modality in conjunction with low magnification of IRIS in a combined instrument

  5. Analysis and amelioration about the cross-sensitivity of a high resolution MOEMS accelerometer based on diffraction grating

    Science.gov (United States)

    Lu, Qianbo; Bai, Jian; Wang, Kaiwei; Lou, Shuqi; Jiao, Xufen; Han, Dandan

    2016-10-01

    Cross-sensitivity is a crucial parameter since it detrimentally affect the performance of an accelerometer, especially for a high resolution accelerometer. In this paper, a suite of analytical and finite-elements-method (FEM) models for characterizing the mechanism and features of the cross-sensitivity of a single-axis MOEMS accelerometer composed of a diffraction grating and a micromachined mechanical sensing chip are presented, which have not been systematically investigated yet. The mechanism and phenomena of the cross-sensitivity of this type MOEMS accelerometer based on diffraction grating differ quite a lot from the traditional ones owing to the identical sensing principle. By analyzing the models, some ameliorations and the modified design are put forward to suppress the cross-sensitivity. The modified design, achieved by double sides etching on a specific double-substrate-layer silicon-on-insulator (SOI) wafer, is validated to have a far smaller cross-sensitivity compared with the design previously reported in the literature. Moreover, this design can suppress the cross-sensitivity dramatically without compromising the acceleration sensitivity and resolution.

  6. tranSMART: An Open Source Knowledge Management and High Content Data Analytics Platform.

    Science.gov (United States)

    Scheufele, Elisabeth; Aronzon, Dina; Coopersmith, Robert; McDuffie, Michael T; Kapoor, Manish; Uhrich, Christopher A; Avitabile, Jean E; Liu, Jinlei; Housman, Dan; Palchuk, Matvey B

    2014-01-01

    The tranSMART knowledge management and high-content analysis platform is a flexible software framework featuring novel research capabilities. It enables analysis of integrated data for the purposes of hypothesis generation, hypothesis validation, and cohort discovery in translational research. tranSMART bridges the prolific world of basic science and clinical practice data at the point of care by merging multiple types of data from disparate sources into a common environment. The application supports data harmonization and integration with analytical pipelines. The application code was released into the open source community in January 2012, with 32 instances in operation. tranSMART's extensible data model and corresponding data integration processes, rapid data analysis features, and open source nature make it an indispensable tool in translational or clinical research.

  7. Piecewise Approximate Analytical Solutions of High-Order Singular Perturbation Problems with a Discontinuous Source Term

    Directory of Open Access Journals (Sweden)

    Essam R. El-Zahar

    2016-01-01

    Full Text Available A reliable algorithm is presented to develop piecewise approximate analytical solutions of third- and fourth-order convection diffusion singular perturbation problems with a discontinuous source term. The algorithm is based on an asymptotic expansion approximation and Differential Transform Method (DTM. First, the original problem is transformed into a weakly coupled system of ODEs and a zero-order asymptotic expansion of the solution is constructed. Then a piecewise smooth solution of the terminal value reduced system is obtained by using DTM and imposing the continuity and smoothness conditions. The error estimate of the method is presented. The results show that the method is a reliable and convenient asymptotic semianalytical numerical method for treating high-order singular perturbation problems with a discontinuous source term.

  8. Highly sensitive multianalyte immunochromatographic test strip for rapid chemiluminescent detection of ractopamine and salbutamol

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Hongfei; Han, Jing; Yang, Shijia; Wang, Zhenxing; Wang, Lin; Fu, Zhifeng, E-mail: fuzf@swu.edu.cn

    2014-08-11

    Graphical abstract: A multianalyte immunochromatographic test strip was developed for the rapid detection of two β{sub 2}-agonists. Due to the application of chemiluminescent detection, this quantitative method shows much higher sensitivity. - Highlights: • An immunochromatographic test strip was developed for detection of multiple β{sub 2}-agonists. • The whole assay process can be completed within 20 min. • The proposed method shows much higher sensitivity due to the application of CL detection. • It is a portable analytical tool suitable for field analysis and rapid screening. - Abstract: A novel immunochromatographic assay (ICA) was proposed for rapid and multiple assay of β{sub 2}-agonists, by utilizing ractopamine (RAC) and salbutamol (SAL) as the models. Owing to the introduction of chemiluminescent (CL) approach, the proposed protocol shows much higher sensitivity. In this work, the described ICA was based on a competitive format, and horseradish peroxidase-tagged antibodies were used as highly sensitive CL probes. Quantitative analysis of β{sub 2}-agonists was achieved by recording the CL signals of the probes captured on the two test zones of the nitrocellulose membrane. Under the optimum conditions, RAC and SAL could be detected within the linear ranges of 0.50–40 and 0.10–50 ng mL{sup −1}, with the detection limits of 0.20 and 0.040 ng mL{sup −1} (S/N = 3), respectively. The whole process for multianalyte immunoassay of RAC and SAL can be completed within 20 min. Furthermore, the test strip was validated with spiked swine urine samples and the results showed that this method was reliable in measuring β{sub 2}-agonists in swine urine. This CL-based multianalyte test strip shows a series of advantages such as high sensitivity, ideal selectivity, simple manipulation, high assay efficiency and low cost. Thus, it opens up new pathway for rapid screening and field analysis, and shows a promising prospect in food safety.

  9. A combined HM-PCR/SNuPE method for high sensitive detection of rare DNA methylation

    Directory of Open Access Journals (Sweden)

    Tierling Sascha

    2010-06-01

    Full Text Available Abstract Background DNA methylation changes are widely used as early molecular markers in cancer detection. Sensitive detection and classification of rare methylation changes in DNA extracted from circulating body fluids or complex tissue samples is crucial for the understanding of tumor etiology, clinical diagnosis and treatment. In this paper, we describe a combined method to monitor the presence of methylated tumor DNA in an excess of unmethylated background DNA of non-tumorous cells. The method combines heavy methyl-PCR, which favors preferential amplification of methylated marker sequence from bisulfite-treated DNA with a methylation-specific single nucleotide primer extension monitored by ion-pair, reversed-phase, high-performance liquid chromatography separation. Results This combined method allows detection of 14 pg (that is, four to five genomic copies of methylated chromosomal DNA in a 2000-fold excess (that is, 50 ng of unmethylated chromosomal background, with an analytical sensitivity of > 90%. We outline a detailed protocol for the combined assay on two examples of known cancer markers (SEPT9 and TMEFF2 and discuss general aspects of assay design and data interpretation. Finally, we provide an application example for rapid testing on tumor methylation in plasma DNA derived from a small cohort of patients with colorectal cancer. Conclusion The method allows unambiguous detection of rare DNA methylation, for example in body fluid or DNA isolates from cells or tissues, with very high sensitivity and accuracy. The application combines standard technologies and can easily be adapted to any target region of interest. It does not require costly reagents and can be used for routine screening of many samples.

  10. Characterization of Three High Efficiency and Blue Sensitive Silicon Photomultipliers

    CERN Document Server

    Otte, Adam Nepomuk; Nguyen, Thanh; Purushotham, Dhruv

    2016-01-01

    We report about the optical and electrical characterization of three high efficiency and blue sensitive Silicon photomultipliers from FBK, Hamamatsu, and SensL. Key features of the tested devices when operated at 90% breakdown probability are peak photon detection efficiencies between 40% and 55%, temperature dependencies of gain and PDE that are less than 1%/$^{\\circ}$C, dark rates of $\\sim$50\\,kHz/mm$^{2}$ at room temperature, afterpulsing of about 2%, and direct optical crosstalk between 6% and 20%. The characteristics of all three devices impressively demonstrate how the Silicon-photomultiplier technology has improved over the past ten years. It is further demonstrated how the voltage and temperature characteristics of a number of quantities can be parameterized on the basis of physical models. The models provide a deeper understanding of the device characteristics over a wide bias and temperature range. They also serve as examples how producers could provide the characteristics of their SiPMs to users. A...

  11. Characterization of three high efficiency and blue sensitive silicon photomultipliers

    Science.gov (United States)

    Otte, Adam Nepomuk; Garcia, Distefano; Nguyen, Thanh; Purushotham, Dhruv

    2017-02-01

    We report about the optical and electrical characterization of three high efficiency and blue sensitive Silicon photomultipliers from FBK, Hamamatsu, and SensL. Key features of the tested devices when operated at 90% breakdown probability are peak photon detection efficiencies between 40% and 55%, temperature dependencies of gain and PDE that are less than 1%/°C, dark rates of ∼50 kHz/mm2 at room temperature, afterpulsing of about 2%, and direct optical crosstalk between 6% and 20%. The characteristics of all three devices impressively demonstrate how the Silicon-photomultiplier technology has improved over the past ten years. It is further demonstrated how the voltage and temperature characteristics of a number of quantities can be parameterized on the basis of physical models. The models provide a deeper understanding of the device characteristics over a wide bias and temperature range. They also serve as examples how producers could provide the characteristics of their SiPMs to users. A standardized parameterization of SiPMs would enable users to find the optimal SiPM for their application and the operating point of SiPMs without having to perform measurements thus significantly reducing design and development cycles.

  12. High Speed Pressure Sensitive Paint for Dynamic Testing

    Science.gov (United States)

    Pena, Carolina; Chism, Kyle; Hubner, Paul

    2016-11-01

    Pressure sensitive paint (PSP) allows engineers to obtain accurate, high-spatial-resolution measurements of pressure fields over a structure. The pressure is directly related to the luminescence emitted by the paint due to oxygen quenching. Fast PSP has a higher surface area due to its porosity compared to conventional PSP, which enables faster diffusion and measurements to be acquired three orders of magnitude faster than with conventional PSP. A fast time response is needed when testing vibrating structures due to fluid-structure interaction. The goal of this summer project was to set-up, test and analyze the pressure field of an impinging air jet on a vibrating cantilever beam using Fast PSP. Software routines were developed for the processing of the emission images, videos of a static beam coated with Fast PSP were acquired with the air jet on and off, and the intensities of these two cases were ratioed and calibrated to pressure. Going forward, unsteady pressures on a vibrating beam will be measured and presented. Eventually, the long-term goal is to integrate luminescent pressure and strain measurement techniques, simultaneously using Fast PSP and a luminescent photoelastic coating on vibrating structures. Funding from NSF REU site Grant EEC 1358991 is greatly appreciated.

  13. Ultra-high sensitivity imaging of cancer using SERRS nanoparticles

    Science.gov (United States)

    Kircher, Moritz F.

    2016-05-01

    "Surface-enhanced Raman spectroscopy" (SERS) nanoparticles have gained much attention in recent years for in silico, in vitro and in vivo sensing applications. Our group has developed novel generations of biocompatible "surfaceenhanced resonance Raman spectroscopy" (SERRS) nanoparticles as novel molecular imaging agents. Via rigorous optimization of the different variables contributing to the Raman enhancement, we were able to design SERRS nanoparticles with so far unprecedented sensitivity of detection under in vivo imaging conditions (femto-attomolar range). This has resulted in our ability to visualize, with a single nanoparticle, many different cancer types (after intravenous injection) in mouse models. The cancer types we have tested so far include brain, breast, esophagus, stomach, pancreas, colon, sarcoma, and prostate cancer. All mouse models used are state-of-the-art and closely mimic the tumor biology in their human counterparts. In these animals, we were able to visualize not only the bulk tumors, but importantly also microscopic extensions and locoregional satellite metastases, thus delineating for the first time the true extent of tumor spread. Moreover, the particles enable the detection of premalignant lesions. Given their inert composition they are expected to have a high chance for clinical translation, where we envision them to have an impact in various scenarios ranging from early detection, image-guidance in open or minimally invasive surgical procedures, to noninvasive imaging in conjunction with spatially offset (SESORS) Raman detection devices.

  14. Fabrication of highly efficient flexible dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Chang, H., E-mail: f10381@ntut.edu.t [Department of Mechanical Engineering, National Taipei University of Technology, No.1 Sec.3, Chung Hsiao E. Rd., Taipei 10608, Taiwan (China); Chen, T.L. [Department of Industrial Design, National Taipei University of Technology, No.1 Sec.3, Chung Hsiao E. Rd., Taipei 10608, Taiwan (China); Huang, K.D. [Department of Vehicle Engineering, National Taipei University of Technology, No.1 Sec.3, Chung Hsiao E. Rd., Taipei 10608, Taiwan (China); Chien, S.H. [Institute of Chemistry, Academia Sinica, No. 128 Sec.2, Academia Rd., Nankang, Taipei 11529, Taiwan (China); Hung, K.C. [Department of Mechanical Engineering, National Taipei University of Technology, No.1 Sec.3, Chung Hsiao E. Rd., Taipei 10608, Taiwan (China)

    2010-08-15

    The paper studies the fabrication of a flexible dye-sensitized solar cell (DSSC). The photoelectrode substrates are flexible stainless steel sheet with thickness 0.07 mm and titanium (Ti) sheet with thickness 0.25 mm. For the photoelectrode fabrication process, eletrophoresis deposition (EPD) was employed for its merits of low-cost and fast fabrication. With an electric field of 40 V/cm, after undergoing EPD process twice, the TiO{sub 2} nanofilm thickness could be controlled to around 13 {mu}m thick. In addition, to achieve counter electrode, sputtering method was applied to deposit Pt on ITO-PET, resulting in thin films with four different thicknesses of 5, 8, 11 and 14 nm. The experimental results showed that the best colloid solution used in EPD process was a mixture of 100 ml isopropyl alcohol (IPA) and 0.4 g commercial TiO{sub 2} nanoparticles, Degussa P25. The best flatness for a 13 {mu}m thick film could be acquired under an electric field of 40 V/cm. Comparing the photoelectric conversion efficiency values of DSSC assembled by counter electrodes with different Pt thicknesses, the experimental results showed that the best Pt thickness was 11 nm, and the conversion efficiency could reach as high as 2.91%.

  15. ASIC for High Rate 3D Position Sensitive Detectors

    Energy Technology Data Exchange (ETDEWEB)

    Vernon, E.; De Geronimo, G.; Ackley, K.; Fried, J.; He, Z.; Herman, C.; Zhang, F.

    2010-06-16

    We report on the development of an application specific integrated circuit (ASIC) for 3D position sensitive detectors (3D PSD). The ASIC is designed to operate with pixelated wide bandgap sensors like Cadmium-Zinc-Telluride (CZT), Mercuric Iodide (Hgl2) and Thallium Bromide (TIBr). It measures the amplitudes and timings associated with an ionizing event on 128 anodes, the anode grid, and the cathode. Each channel provides low-noise charge amplification, high-order shaping with peaking time adjustable from 250 ns to 12 {micro}s, gain adjustable to 20 mV/fC or 120 mV/fC (for a dynamic range of 3.2 MeV and 530 keV in CZT), amplitude discrimination with 5-bit trimming, and positive and negative peak and timing detections. The readout can be full or sparse, based on a flag and single- or multi-cycle token passing. All channels, triggered channels only, or triggered with neighbors can be read out thus increasing the rate capability of the system to more than 10 kcps. The ASIC dissipates 330 mW which corresponds to about 2.5 mW per channel.

  16. A new analytical model of high voltage silicon on insulator (SOI) thin film devices

    Institute of Scientific and Technical Information of China (English)

    Hu Sheng-Dong; Zhang Bo; Li Zhao-Ji

    2009-01-01

    A new analytical model of high voltage silicon on insulator (SOI) thin film devices is proposed, and a formula of silicon critical electric field is derived as a function of silicon film thickness by solving a 2D Poisson equation from an effective ionization rate, with a threshold energy taken into account for electron multiplying. Unlike a conventional silicon critical electric field that is constant and independent of silicon film thickness, the proposed silicon critical electric field increases sharply with silicon film thickness decreasing especially in the case of thin films, and can come to 141 V/μm at a film thickness of 0.1 μm which is much larger than the normal value of about 30 V/μm. From the proposed formula of silicon critical electric field, the expressions of dielectric layer electric field and vertical breakdown voltage (VB,V) are obtained. Based on the model, an ultra thin film can be used to enhance dielectric layer electric field and so increase vertical breakdown voltage for SOI devices because of its high silicon critical electric field, and with a dielectric layer thickness of 2 μm the vertical breakdown voltages reach 852 and 300V for the silicon film thicknesses of 0.1 and 5μm, respectively. In addition, a relation between dielectric layer thickness and silicon film thickness is obtained, indicating a minimum vertical breakdown voltage that should be avoided when an SOI device is designed. 2D simulated results and some experimental results are in good agreement with analytical results.

  17. Analytical study of the liquid phase transient behavior of a high temperature heat pipe

    Science.gov (United States)

    Roche, Gregory Lawrence

    1988-09-01

    The transient operation of the liquid phase of a high temperature heat pipe is studied. The study was conducted in support of advanced heat pipe applications that require reliable transport of high temperature drops and significant distances under a broad spectrum of operating conditions. The heat pipe configuration studied consists of a sealed cylindrical enclosure containing a capillary wick structure and sodium working fluid. The wick is an annular flow channel configuration formed between the enclosure interior wall and a concentric cylindrical tube of fine pore screen. The study approach is analytical through the solution of the governing equations. The energy equation is solved over the pipe wall and liquid region using the finite difference Peaceman-Rachford alternating direction implicit numerical method. The continuity and momentum equations are solved over the liquid region by the integral method. The energy equation and liquid dynamics equation are tightly coupled due to the phase change process at the liquid-vapor interface. A kinetic theory model is used to define the phase change process in terms of the temperature jump between the liquid-vapor surface and the bulk vapor. Extensive auxiliary relations, including sodium properties as functions of temperature, are used to close the analytical system. The solution procedure is implemented in a FORTRAN algorithm with some optimization features to take advantage of the IBM System/370 Model 3090 vectorization facility. The code was intended for coupling to a vapor phase algorithm so that the entire heat pipe problem could be solved. As a test of code capabilities, the vapor phase was approximated in a simple manner.

  18. Preservatives and neutralizing substances in milk: analytical sensitivity of official specific and nonspecific tests, microbial inhibition effect, and residue persistence in milk

    Directory of Open Access Journals (Sweden)

    Livia Cavaletti Corrêa da Silva

    2015-09-01

    Full Text Available Milk fraud has been a recurring problem in Brazil; thus, it is important to know the effect of most frequently used preservatives and neutralizing substances as well as the detection capability of official tests. The objective of this study was to evaluate the analytical sensitivity of legislation-described tests and nonspecific microbial inhibition tests, and to investigate the effect of such substances on microbial growth inhibition and the persistence of detectable residues after 24/48h of refrigeration. Batches of raw milk, free from any contaminant, were divided into aliquots and mixed with different concentrations of formaldehyde, hydrogen peroxide, sodium hypochlorite, chlorine, chlorinated alkaline detergent, or sodium hydroxide. The analytical sensitivity of the official tests was 0.005%, 0.003%, and 0.013% for formaldehyde, hydrogen peroxide, and hypochlorite, respectively. Chlorine and chlorinated alkaline detergent were not detected by regulatory tests. In the tests for neutralizing substances, sodium hydroxide could not be detected when acidity was accurately neutralized. The yogurt culture test gave results similar to those obtained by official tests for the detection of specific substances. Concentrations of 0.05% of formaldehyde, 0.003% of hydrogen peroxide and 0.013% of sodium hypochlorite significantly reduced (P

  19. Adjoint sensitivity analysis of high frequency structures with Matlab

    CERN Document Server

    Bakr, Mohamed; Demir, Veysel

    2017-01-01

    This book covers the theory of adjoint sensitivity analysis and uses the popular FDTD (finite-difference time-domain) method to show how wideband sensitivities can be efficiently estimated for different types of materials and structures. It includes a variety of MATLAB® examples to help readers absorb the content more easily.

  20. Development, fabrication, and modeling of highly sensitive conjugated polymer based piezoresistive sensors in electronic skin applications

    Science.gov (United States)

    Khalili, Nazanin; Naguib, Hani E.; Kwon, Roy H.

    2016-04-01

    Human intervention can be replaced through development of tools resulted from utilizing sensing devices possessing a wide range of applications including humanoid robots or remote and minimally invasive surgeries. Similar to the five human senses, sensors interface with their surroundings to stimulate a suitable response or action. The sense of touch which arises in human skin is among the most challenging senses to emulate due to its ultra high sensitivity. This has brought forth novel challenging issues to consider in the field of biomimetic robotics. In this work, using a multiphase reaction, a polypyrrole (PPy) based hydrogel is developed as a resistive type pressure sensor with an intrinsically elastic microstructure stemming from three dimensional hollow spheres. Furthermore, a semi-analytical constriction resistance model accounting for the real contact area between the PPy hydrogel sensors and the electrode along with the dependency of the contact resistance change on the applied load is developed. The model is then solved using a Monte Carlo technique and the sensitivity of the sensor is obtained. The experimental results showed the good tracking ability of the proposed model.

  1. Electronic characterization of lithographically patterned microcoils for high sensitivity NMR detection.

    Science.gov (United States)

    Demas, Vasiliki; Bernhardt, Anthony; Malba, Vince; Adams, Kristl L; Evans, Lee; Harvey, Christopher; Maxwell, Robert S; Herberg, Julie L

    2009-09-01

    Nuclear magnetic resonance (NMR) offers a non-destructive, powerful, structure-specific analytical method for the identification of chemical and biological systems. The use of radio frequency (RF) microcoils has been shown to increase the sensitivity in mass-limited samples. Recent advances in micro-receiver technology have further demonstrated a substantial increase in mass sensitivity [D.L. Olson, T.L. Peck, A.G. Webb, R.L. Magin, J.V. Sweedler, High-resolution microcoil H-1-NMR for mass-limited, nanoliter-volume samples, Science 270 (5244) (1995) 1967-1970]. Lithographic methods for producing solenoid microcoils possess a level of flexibility and reproducibility that exceeds previous production methods, such as hand winding microcoils. This paper presents electrical characterizations of RF microcoils produced by a unique laser lithography system that can pattern three dimensional surfaces and compares calculated and experimental results to those for wire wound RF microcoils. We show that existing optimization conditions for RF coil design still hold true for RF microcoils produced by lithography. Current lithographic microcoils show somewhat inferior performance to wire wound RF microcoils due to limitations in the existing electroplating technique. In principle, however, when the pitch of the RF microcoil is less than 100mum lithographic coils should show comparable performance to wire wound coils. In the cases of larger pitch, wire cross sections can be significantly larger and resistances lower than microfabricated conductors.

  2. Highly sensitive detection of molecular interactions with plasmonic optical fiber grating sensors.

    Science.gov (United States)

    Voisin, Valérie; Pilate, Julie; Damman, Pascal; Mégret, Patrice; Caucheteur, Christophe

    2014-01-15

    Surface Plasmon resonance (SPR) optical fiber biosensors constitute a miniaturized counterpart to the bulky prism configuration and offer remote operation in very small volumes of analyte. They are a cost-effective and relatively straightforward technique to yield in situ (or even possibly in vivo) molecular detection. The biosensor configuration reported in this work uses nanometric-scale gold-coated tilted fiber Bragg gratings (TFBGs) interrogated by light polarized radially to the optical fiber outer surface, so as to maximize the optical coupling with the SPR. These gratings were recently associated to aptamers to assess their label-free biorecognition capability in buffer and serum solutions. In this work, using the well-acknowledged biotin-streptavidin pair as a benchmark, we go forward in the demonstration of their unique sensitivity. In addition to the monitoring of the self-assembled monolayer (SAM) in real time, we report an unprecedented limit of detection (LOD) as low as 2 pM. Finally, an immunosensing experiment is realized with human transferrin (dissociation constant Kd~10(-8) M(-1)). It allows to assess both the reversibility and the robustness of the SPR-TFBG biosensors and to confirm their high sensitivity.

  3. Highly sensitive NIR PtSi/Si-nanostructure detectors

    Science.gov (United States)

    Li, Hua-gao; Guo, Pei; Yuan, An-bo; Long, Fei; Li, Rui-zhi; Li, Ping; Li, Yi

    2016-10-01

    We report a high external quantum efficiency (EQE) photodiode detector with PtSi/Si-nanostructures. Black silicon nanostructures were fabricated by metal-assist chemical etching (MCE), a 2 nm Pt layer was subsequently deposited on black silicon surface by DC magnetron sputtering system, and PtSi/Si-nanostructures were formed in vacuum annealing at 450 oC for 5 min. As the PtSi/Si-nanostructures presented a spiky shape, the absorption of incident light was remarkably enhanced for the repeat reflection and absorption. The breakdown voltage, dark current, threshold voltage and responsivity of the device were investigated to evaluate the performance of the PtSi/Si-nanostructures detector. The threshold voltage and dark currents of the PtSi/Si-nanostructure photodiode tends to be slightly higher than those of the standard diodes. The breakdown voltage remarkably was reduced because of existing avalanche breakdown in PtSi/Si-nanostructures. However, the photodiodes had high response at room temperature in near infrared region. At -5 V reverse bias voltage, the responsivity was 0.72 A/W in 1064 nm wavelength, and the EQE was 83.9%. By increasing the reverse bias voltage, the responsivity increased. At -60 V reverse bias voltage, the responsivity was 3.5 A/W, and the EQE was 407.5%, which means the quantum efficiency of PtSi/Si-nanostructure photodiodes was about 10 times higher than that of a standard diode. Future research includes how to apply this technology to enhance the NIR sensitivity of image sensors, such as Charge Coupled Devices (CCD).

  4. High temperature and dynamic testing of AHSS for an analytical description of the adiabatic cutting process

    Science.gov (United States)

    Winter, S.; Schmitz, F.; Clausmeyer, T.; Tekkaya, A. E.; F-X Wagner, M.

    2017-03-01

    In the automotive industry, advanced high strength steels (AHSS) are widely used as sheet part components to reduce weight, even though this leads to several challenges. The demand for high-quality shear cutting surfaces that do not require reworking can be fulfilled by adiabatic shear cutting: High strain rates and local temperatures lead to the formation of adiabatic shear bands (ASB). While this process is well suited to produce AHSS parts with excellent cutting surface quality, a fundamental understanding of the process is still missing today. In this study, compression tests in a Split-Hopkinson Pressure Bar with an initial strain rate of 1000 s-1 were performed in a temperature range between 200 °C and 1000 °C. The experimental results show that high strength steels with nearly the same mechanical properties at RT may possess a considerably different behavior at higher temperatures. The resulting microstructures after testing at different temperatures were analyzed by optical microscopy. The thermo-mechanical material behavior was then considered in an analytical model. To predict the local temperature increase that occurs during the adiabatic blanking process, experimentally determined flow curves were used. Furthermore, the influence of temperature evolution with respect to phase transformation is discussed. This study contributes to a more complete understanding of the relevant microstructural and thermo-mechanical mechanisms leading to the evolution of ASB during cutting of AHSS.

  5. High throughput modular chambers for rapid evaluation of anesthetic sensitivity

    Directory of Open Access Journals (Sweden)

    Eckmann David M

    2006-11-01

    Full Text Available Abstract Background Anesthetic sensitivity is determined by the interaction of multiple genes. Hence, a dissection of genetic contributors would be aided by precise and high throughput behavioral screens. Traditionally, anesthetic phenotyping has addressed only induction of anesthesia, evaluated with dose-response curves, while ignoring potentially important data on emergence from anesthesia. Methods We designed and built a controlled environment apparatus to permit rapid phenotyping of twenty-four mice simultaneously. We used the loss of righting reflex to indicate anesthetic-induced unconsciousness. After fitting the data to a sigmoidal dose-response curve with variable slope, we calculated the MACLORR (EC50, the Hill coefficient, and the 95% confidence intervals bracketing these values. Upon termination of the anesthetic, Emergence timeRR was determined and expressed as the mean ± standard error for each inhaled anesthetic. Results In agreement with several previously published reports we find that the MACLORR of halothane, isoflurane, and sevoflurane in 8–12 week old C57BL/6J mice is 0.79% (95% confidence interval = 0.78 – 0.79%, 0.91% (95% confidence interval = 0.90 – 0.93%, and 1.96% (95% confidence interval = 1.94 – 1.97%, respectively. Hill coefficients for halothane, isoflurane, and sevoflurane are 24.7 (95% confidence interval = 19.8 – 29.7%, 19.2 (95% confidence interval = 14.0 – 24.3%, and 33.1 (95% confidence interval = 27.3 – 38.8%, respectively. After roughly 2.5 MACLORR • hr exposures, mice take 16.00 ± 1.07, 6.19 ± 0.32, and 2.15 ± 0.12 minutes to emerge from halothane, isoflurane, and sevoflurane, respectively. Conclusion This system enabled assessment of inhaled anesthetic responsiveness with a higher precision than that previously reported. It is broadly adaptable for delivering an inhaled therapeutic (or toxin to a population while monitoring its vital signs, motor reflexes, and providing precise control

  6. An Analytical Delay Model

    Institute of Scientific and Technical Information of China (English)

    MIN Yinghua; LI Zhongcheng

    1999-01-01

    Delay consideration has been a majorissue in design and test of high performance digital circuits. Theassumption of input signal change occurring only when all internal nodesare stable restricts the increase of clock frequency. It is no longertrue for wave pipelining circuits. However, previous logical delaymodels are based on the assumption. In addition, the stable time of arobust delay test generally depends on the longest sensitizable pathdelay. Thus, a new delay model is desirable. This paper explores thenecessity first. Then, Boolean process to analytically describe thelogical and timing behavior of a digital circuit is reviewed. Theconcept of sensitization is redefined precisely in this paper. Based onthe new concept of sensitization, an analytical delay model isintroduced. As a result, many untestable delay faults under thelogical delay model can be tested if the output waveforms can be sampledat more time points. The longest sensitizable path length is computedfor circuit design and delay test.

  7. A highly accurate and analytic equation of state for a hard sphere fluid in random porous media.

    Science.gov (United States)

    Holovko, M; Dong, W

    2009-05-07

    An analytical equation of state (EOS) for a hard sphere fluid confined in random porous media is derived by extending the scaled particle theory to such complex systems with quenched disorders. A simple empirical correction allows us to obtain a highly accurate EOS with errors within the simulation ones. These are the first analytical results for non trivial off-lattice quench-annealed systems.

  8. High-sensitivity high-throughput chip based biosensor array for multiplexed detection of heavy metals

    Science.gov (United States)

    Yan, Hai; Tang, Naimei; Jairo, Grace A.; Chakravarty, Swapnajit; Blake, Diane A.; Chen, Ray T.

    2016-03-01

    Heavy metal ions released into the environment from industrial processes lead to various health hazards. We propose an on-chip label-free detection approach that allows high-sensitivity and high-throughput detection of heavy metals. The sensing device consists of 2-dimensional photonic crystal microcavities that are combined by multimode interferometer to form a sensor array. We experimentally demonstrate the detection of cadmium-chelate conjugate with concentration as low as 5 parts-per-billion (ppb).

  9. Mismatches in Phenology of Birds and Their Food Due to Climate Change: Big Data, Analytical Challenges, and Scale Sensitivity

    Science.gov (United States)

    Mayor, S.; Andrew, M. E.; Elmendorf, S.; Guralnick, R. P.; Minor, E. S.; Schneider, D.; Tersigni, V.; Thibault, K. M.; Tingley, M. W.; Withey, J. C.

    2013-12-01

    We explored analytical issues that come with challenging ecological concepts against large data sets. As an example, we examined the expected mismatch between the phenology (annual timing) of endothermic migratory birds with the phenology of primarily ectothermic (degree-day dependent) food resources. We hypothesized that bird phenology, which is often tightly hormonally tied to day length cues would be increasing out of phase the phenology of their food resources, due to increases in both mean and variability of spring temperatures. Specifically, we tested whether bird populations have been able to match their migration times to the timing of spring 'greenup', when food resources become plentiful. If not, we also test if suboptimal migration timing resulted in negative fitness consequences for individual bird species? We expected (1) a mismatch between optimal migration time and observed migration time; (2) greater variation in mean timing of ectothermic prey resources than migratory arrival of endothermic birds; (3) higher per capita survival and reproduction of species with the smallest optimal/observed migration timing mismatch. We tested these expectations with rich datasets extensive in both time and space. We brought together nearly a decade of migratory arrival records for over 100 bird species across the continental U.S. (eBird) with remotely sensed (MODIS) time of spring greenup, which is concurrent with insect abundance, and survival and reproduction estimates for each bird species (MAPS). In testing these questions with large data sets, we encountered several challenges. First, selecting the spatial scale(s) of analyses involve a priori estimation of scale(s) at which birds select food resources, and mismatches depend on analytical scale. To assess a mismatch in phenology (between birds and food), we attempted to minimize a mismatch in scales (between analyses and phenomena). Second, forming causal linkages between variables relied on previous

  10. Electromagnetic environment around a high-speed railway using analytical technique

    Institute of Scientific and Technical Information of China (English)

    Yong-jian ZHI; Bin ZHANG; Kai LI; Xiao-yan HUANG; You-tong FANG; Wen-ping CAO

    2011-01-01

    A switched-mode unit used in electric locomotive generates a strong high frequency conducted electromagnetic interference (EMI),which radiates electromagnetic energy through railway lines.Evaluation of magnetic field using analytical technique based on contour integral is presented,in order to assess the electromagnetic environment around a high-speed railway.Actual railway multiconductor finitely long overhead lines are represented by an infinitely long single line above two-layered earth,whose characteristic is different from homogeneous earth.Owing to the constraint of the GB/T 24338-2009 and the high frequency investigated (a few MHz),only the magnetic fields are examined.The magnetic fields consist of four components: the direct wave,the ideal reflected wave or image wave,the trapped surface wave,and the lateral wave.The calculation results proved that due to the presence of the trapped surface wave,the magnetic field of the observer point on the interface is strongly influenced,when the line is on or closed to the interface.

  11. Designing Progressive and Interactive Analytics Processes for High-Dimensional Data Analysis.

    Science.gov (United States)

    Turkay, Cagatay; Kaya, Erdem; Balcisoy, Selim; Hauser, Helwig

    2017-01-01

    In interactive data analysis processes, the dialogue between the human and the computer is the enabling mechanism that can lead to actionable observations about the phenomena being investigated. It is of paramount importance that this dialogue is not interrupted by slow computational mechanisms that do not consider any known temporal human-computer interaction characteristics that prioritize the perceptual and cognitive capabilities of the users. In cases where the analysis involves an integrated computational method, for instance to reduce the dimensionality of the data or to perform clustering, such non-optimal processes are often likely. To remedy this, progressive computations, where results are iteratively improved, are getting increasing interest in visual analytics. In this paper, we present techniques and design considerations to incorporate progressive methods within interactive analysis processes that involve high-dimensional data. We define methodologies to facilitate processes that adhere to the perceptual characteristics of users and describe how online algorithms can be incorporated within these. A set of design recommendations and according methods to support analysts in accomplishing high-dimensional data analysis tasks are then presented. Our arguments and decisions here are informed by observations gathered over a series of analysis sessions with analysts from finance. We document observations and recommendations from this study and present evidence on how our approach contribute to the efficiency and productivity of interactive visual analysis sessions involving high-dimensional data.

  12. Fabrication of gold nanoparticle-embedded metal-organic framework for highly sensitive surface-enhanced Raman scattering detection.

    Science.gov (United States)

    Hu, Yuling; Liao, Jia; Wang, Dongmei; Li, Gongke

    2014-04-15

    Surface-enhanced Raman scattering (SERS) signals strongly rely on the interactions and distance between analyte molecules and metallic nanostructures. In this work, the use of a gold nanoparticle (AuNP)-embedded metal-organic framework was introduced for the highly sensitive SERS detection. The AuNPs were in situ grown and encapsulated within the host matrix of MIL-101 by a solution impregnation strategy. The as-synthesized AuNPs/MIL-101 nanocomposites combined the localized surface plasmon resonance properties of the gold nanoparticles and the high adsorption capability of metal-organic framework, making them highly sensitive SERS substrates by effectively preconcentrating analytes in close proximity to the electromagnetic fields at the SERS-active metal surface. We discussed the fabrication, physical characterization, and SERS activity of our novel substrates by measuring the Raman signals of a variety of model analytes. The SERS substrate was found to be highly sensitive, robust, and amiable to several different target analytes. A SERS detection limit of 41.75 and 0.54 fmol for Rhodamine 6G and benzadine, respectively, was demonstrated. The substrate also showed high stability and reproducibility, as well as molecular sieving effect thanks to the protective shell of the metal-organic framework. Subsequently, the potential practical application of the novel SERS substrate was evaluated by quantitative analysis of organic pollutant p-phenylenediamine in environmental water and tumor marker alpha-fetoprotein in human serum. The method showed good linearity between 1.0 and 100.0 ng/mL for p-phenylenediamine and 1.0-130.0 ng/mL for alpha-fetoprotein with the correlation coefficients of 0.9950 and -0.9938, respectively. The recoveries ranged from 80.5% to 114.7% for p-phenylenediamine in environmental water and 79.3% to 107.3% for alpha-fetoprotein in human serum. These results foresee promising application of the novel metal-organic framework based composites as

  13. Restoring ecological integrity in highly regulated rivers: the role of baseline data and analytical references.

    Science.gov (United States)

    Downs, Peter W; Singer, Maia S; Orr, Bruce K; Diggory, Zooey E; Church, Tamara C; Stella, J C

    2011-10-01

    The goal of restoring ecological integrity in rivers is frequently accompanied by an assumption that a comparative reference reach can be identified to represent minimally impaired conditions. However, in many regulated rivers, no credible historical, morphological or process-based reference reach exists. Resilient restoration designs should instead be framed around naturalization, using multiple analytical references derived from empirically-calibrated field- and model-based techniques to develop an integrated ecological reference condition. This requires baseline data which are rarely collected despite increasing evidence for systematic deficiencies in restoration practice. We illustrate the utility of baseline data collection in restoration planning for the highly fragmented and regulated lower Merced River, California, USA. The restoration design was developed using various baseline data surveys, monitoring, and modeling within an adaptive management framework. Baseline data assisted in transforming conceptual models of ecosystem function into specific restoration challenges, defining analytical references of the expected relationships among ecological parameters required for restoration, and specifying performance criteria for post-project monitoring and evaluation. In this way the study is an example of process-based morphological restoration designed to prompt recovery of ecosystem processes and resilience. For the Merced River, we illustrate that project-specific baseline data collection is a necessary precursor in developing performance-based restoration designs and addressing scale-related uncertainties, such as whether periodic gravel augmentation will sustain bed recovery and whether piecemeal efforts will improve ecological integrity. Given the numerous impediments to full, historical, restoration in many river systems, it seems apparent that projects of naturalization are a critical step in reducing the deleterious impacts of fragmented rivers

  14. [Detection of anti-ENA autoantibodies in patients with systemic connective tissue diseases. Analytical variability and diagnostic sensitivity of 4 methods].

    Science.gov (United States)

    Villalta, D; Bizzaro, N; Tonutti, E; Visentin, D; Manoni, F; Piazza, A; Toffolo, L; Rizzotti, P; Clemen, P; Pradella, M; Bassetti, D; Tozzoli, R

    1999-11-01

    This study was designed to assess the analytical sensitivity and rate of agreement between commercial methods and reagents, among the most used in Italy for the detection of autoantibodies to extractable nuclear antigens (ENA). Sixty-eight serum samples from patients with clinically diagnosed systemic rheumatic diseases were aliquoted and distributed to 4 hospital laboratories; three ELISA (Elias, Shield, Inova) and 1 immunoblot method (Euroimmun) were used. Overall agreement between the test reagents, for each anti-ENA specificity, was 69.1% for Ro/SSA, 83.3% for La/SSB, 70.6% for RNP, 73.5% for Sm, 91.1% for Jo1, and 82.3% for Scl70. Lack of specificity (i.e., false positive reactions) was the most important cause of low concordance. When the data were analysed according to the clinical diagnosis, total agreement and specificity improved. However, a significant difference in terms of sensitivity was observed in the SLE group (30 sera) for RNP (positivity ranged from 20% to 43%) and for Sm (from 7% to 37%), and in the Sjögren's syndrome group (13 sera) for anti-La/SSB (from 8% to 38%). Comparable data were obtained for anti-Ro/SSA (from 70% to 77%) both in the SLE and the Sjögren's syndrome group. Sensitivity of all 4 reagents was good in detecting anti-Scl70 autoantibodies in the 8 patients with diffuse systemic sclerosis, as well as anti-Jo1 autoantibody in the 5 polymyositis patients, with a 100% and a 95% agreement, respectively. These data suggest the need of a better standardization of commercial reagents and analytical procedures, and the opportunity that every laboratory should perform anti-ENA determination by at least two different methods, since none of the methods tested was completely reliable in detecting all anti-ENA autoantibody specificities.

  15. High sensitivity fiber Bragg grating pressure difference sensor

    Institute of Scientific and Technical Information of China (English)

    Haiwei Fu(傅海威); Junmei Fu(傅君眉); Xueguang Qiao(乔学光)

    2004-01-01

    Based on the effect of fiber Bragg grating (FBG) pressure difference sensitivity enhancement by encapsulating the FBG with uniform strength beam and metal bellows, a FBG pressure difference sensor is proposed, and its mechanism is also discussed. The relationship between Bragg wavelength and the pressure difference is derived, and the expression of the pressure difference sensitivity coefficient is also given. It is indicated that there is good linear relation between the Bragg wavelength shift and the pressure difference of the sensor. The theoretical and experimental pressure difference sensitivity coefficients are 38.67 and 37.6 nm/MPa, which are 12890 and 12533 times of that of the bare FBG, respectively. The pressure difference sensitivity and dynamic range can be easily changed by changing the size, Young's modulus, and Poisson's ratio of the beam and the bellows.

  16. Design of a High Sensitivity GNSS receiver for Lunar missions

    Science.gov (United States)

    Musumeci, Luciano; Dovis, Fabio; Silva, João S.; da Silva, Pedro F.; Lopes, Hugo D.

    2016-06-01

    This paper presents the design of a satellite navigation receiver architecture tailored for future Lunar exploration missions, demonstrating the feasibility of using Global Navigation Satellite Systems signals integrated with an orbital filter to achieve such a scope. It analyzes the performance of a navigation solution based on pseudorange and pseudorange rate measurements, generated through the processing of very weak signals of the Global Positioning System (GPS) L1/L5 and Galileo E1/E5 frequency bands. In critical scenarios (e.g. during manoeuvres) acceleration and attitude measurements from additional sensors complementing the GNSS measurements are integrated with the GNSS measurement to match the positioning requirement. A review of environment characteristics (dynamics, geometry and signal power) for the different phases of a reference Lunar mission is provided, focusing on the stringent requirements of the Descent, Approach and Hazard Detection and Avoidance phase. The design of High Sensitivity acquisition and tracking schemes is supported by an extensive simulation test campaign using a software receiver implementation and navigation results are validated by means of an end-to-end software simulator. Acquisition and tracking of GPS and Galileo signals of the L1/E1 and L5/E5a bands was successfully demonstrated for Carrier-to-Noise density ratios as low as 5-8 dB-Hz. The proposed navigation architecture provides acceptable performances during the considered critical phases, granting position and velocity errors below 61.4 m and 3.2 m/s, respectively, for the 99.7% of the mission time.

  17. Stepwise chemical reaction strategy for highly sensitive electrochemiluminescent detection of dopamine.

    Science.gov (United States)

    Zhang, Lei; Cheng, Yan; Lei, Jianping; Liu, Yueting; Hao, Qing; Ju, Huangxian

    2013-08-20

    A stepwise chemical reaction strategy based on the specific recognition of boronic acid to diol, and N-hydroxysuccinimide (NHS) ester to amine group, was designed to construct a "signal on" electrochemiluminescence (ECL) platform for highly sensitive detection of dopamine. A boronic acid-functionalized pyrene probe was synthesized and was self-assembled on the sidewalls of carbon nanotubes via π-π stacking interactions as capture probes on a glassy carbon electrode. Meanwhile, 3,3'-dithiodipropionic acid di(N-hydroxysuccinimide ester) (DSP)-functionalized CdTe quantum dots (QDs) were designed as signal probes and characterized with transmission electron microscopy and spectroscopic techniques. Upon stepwise chemical reaction of dopamine with boronic acid and then DSP-QDs, the QDs were captured on the electrode as ECL emitters for signal readout, leading to an ultralow background signal. By using O2 as an endogenous coreactant, the "signal on" ECL method was employed to quantify the concentration of dopamine from 50 pM to 10 nM with a detection limit of 26 pM. Moreover, the stepwise chemical reaction-based biosensor showed high specificity against cerebral interference and was successfully applied in the detection of dopamine in cerebrospinal fluid samples. The stepwise chemical reaction strategy should be a new concept for the design of highly selective analytical methods for the detection of small biomolecules.

  18. A high sensitive fiber-optic strain sensor with tunable temperature sensitivity for temperature-compensation measurement

    Science.gov (United States)

    Hu, Jie; Huang, Hui; Bai, Min; Zhan, Tingting; Yang, Zhibo; Yu, Yan; Qu, Bo

    2017-02-01

    A high sensitive fiber-optic strain sensor, which consists of a cantilever, a tandem rod and a fiber collimator, was proposed. The tandem rod, which transfer the applied strain to the cantilever, was used for tuning the temperature sensitivity from ‑0.15 to 0.19 dB/°C via changing the length ratio of the rods. Moreover, due to the small beam divergence of the collimator, high strain sensitivity can be realized via incident-angle sensitive detection-mechanism. A strain detection-range of 1.1 × 103 με (with a sensing length of 21.5 mm), a detection limit of 5.7 × 10‑3 με, and a maximum operating frequency of 1.18 KHz were demonstrated. This sensor is promising for compensating the thermal-expansion of various target objects.

  19. Development of a synchronous enzyme-reaction system for a highly sensitive enzyme immunoassay.

    Science.gov (United States)

    Inouye, Kuniyo; Ueno, Iori; Yokoyama, Shin-ichi; Sakaki, Toshiyuki

    2002-01-01

    A synchronous enzyme-reaction system using water-soluble formazan and a non-enzymatic electron mediator was developed and applied to an enzyme immunoassay (EIA). The reaction system consists of four steps: (I) dephosphorylation of NADP(+) to produce NAD(+) by alkaline phosphatase (ALP), (II) reduction of NAD(+) to produce NADH with oxidation of ethanol to yield acetaldehyde by alcohol dehydrogenase (ADH), (III) reduction of water-soluble tetrazolium salt (WST-1) to produce formazan by NADH via 1-methoxy-5-methyl-phenazinium methyl sulfate (PMS), and (IV) re-reduction of NAD(+) to produce NADH by ADH. During each cycle, one molecule of tetrazolium is converted to one molecule of formazan. The concentration of formazan during the reaction was given by second-order polynomials of the reaction time. Kinetic studies strongly suggested that the synchronous enzyme-reaction system had the potential to detect an analyte at the attomole level in EIA. On the basis of the kinetic studies, optimal conditions for EIA incorporating the synchronous system were examined. NADP(+) was purified thoroughly to remove minor traces of NAD(+) in the preparation, and an ADH preparation contaminated with the lowest level of ALP activity was used. When the synchronous system was applied to a sandwich-type EIA for human C-reactive protein, the protein was detected with a sensitivity of 50 attomole per well of a micro-titer plate (0.1 ml) in a 1-h reaction. In addition, EIA with water-soluble formazan showed a more quantitative and sensitive result than that with insoluble formazan. These findings indicated that the (WST-1)-PMS system introduced in this study has a great potential for highly sensitive enzyme immunoassay.

  20. Increasing the Analytical Sensitivity by Oligonucleotides Modified with Para- and Ortho-Twisted Intercalating Nucleic Acids - TINA

    DEFF Research Database (Denmark)

    Schneider, Uffe V; Géci, Imrich; Jøhnk, Nina

    2011-01-01

    The sensitivity and specificity of clinical diagnostic assays using DNA hybridization techniques are limited by the dissociation of double-stranded DNA (dsDNA) antiparallel duplex helices. This situation can be improved by addition of DNA stabilizing molecules such as nucleic acid intercalators....... Here, we report the synthesis of a novel ortho-Twisted Intercalating Nucleic Acid (TINA) amidite utilizing the phosphoramidite approach, and examine the stabilizing effect of ortho- and para-TINA molecules in antiparallel DNA duplex formation. In a thermal stability assay, ortho- and para......-TINA molecules increased the melting point (Tm) of Watson-Crick based antiparallel DNA duplexes. The increase in Tm was greatest when the intercalators were placed at the 5' and 3' termini (preferable) or, if placed internally, for each half or whole helix turn. Terminally positioned TINA molecules improved...

  1. A less sensitive detector does not necessarily result in a less sensitive method: fast quantification of 13 antiretroviral analytes in plasma with liquid chromatography coupled with tandem mass spectrometry.

    Science.gov (United States)

    Ter Heine, Rob; Rosing, Hilde; Beijnen, Jos H; Huitema, Alwin D R

    2010-08-01

    We previously developed a method for the simultaneous determination of the human immunodeficiency protease inhibitors: amprenavir, atazanavir, darunavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir and tipranavir, the active nelfinavir metabolite M8 the non-nucleoside reverse transcriptase inhibitors efavirenz, nevirapine and etravirine and the internal standards dibenzepine, (13)C(6)-efavirenz, D5-saquinavir and D6-indinavir in plasma using liquid chromatography coupled with tandem mass spectrometry with a Sciex API3000 triple quadrupole mass spectrometer and an analytical run time of only 10 min. We report the transfer of this method from the API3000 to a supposedly less sensitive Sciex API365 mass spectrometer. We describe the steps that were undertaken to optimize the sensitivity and validation of the method that we transferred. We showed that transfer of a method to a putative less sensitive detector did not necessarily result in a less sensitive assay, and this method can be applied in laboratories where older mass spectrometers are available. Ultimately, the performance of the method was validated. Accuracy and precision was within 87%-110% and <13%, respectively. No notable loss in selectivity was observed.

  2. Folded cladding porous shaped photonic crystal fiber with high sensitivity in optical sensing applications: Design and analysis

    Directory of Open Access Journals (Sweden)

    Bikash Kumar Paul

    2017-02-01

    Full Text Available A micro structure folded cladding porous shaped with circular air hole photonic crystal fiber (FP-PCF is proposed and numerically investigated in a broader wavelength range from 1.4 µm to 1.64 µm (E+S+C+L+U for chemical sensing purposes. Employing finite element method (FEM with anisotropic perfectly matched layer (PML various properties of the proposed FP-PCF are numerically inquired. Filling the hole of core with aqueous analyte ethanol (n = 1.354 and tuning different geometric parameters of the fiber, the sensitivity order of 64.19% and the confinement loss of 2.07 × 10-5 dB/m are attained at 1.48 µm wavelength in S band. The investigated numerical simulation result strongly focuses on sensing purposes; because this fiber attained higher sensitivity with lower confinement loss over the operating wavelength. Measuring time of sensitivity, simultaneously confinement loss also inquired. It reflects that confinement loss is highly dependable on PML depth but not for sensitivity. Beside above properties numerical aperture (NA, nonlinearity, and effective area are also computed. This FP-PCF also performed as sensor for other alcohol series (methanol, propanol, butanol, pentanol. Optimized FP-PCF shows higher sensitivity and low confinement loss carrying high impact in the area of chemical as well as gas sensing purposes. Surely it is clear that install such type of sensor will flourish technology massively.

  3. High spectral response heteroleptic ruthenium (II) complexes as sensitizers for dye sensitized solar cells

    Indian Academy of Sciences (India)

    M Chandrasekharam; Ch Srinivasarao; T Suresh; M Anil Reddy; M Raghavender; G Rajkumar; M Srinivasu; P Yella Reddy

    2011-01-01

    Heteroleptic ruthenium(II) bipyridyl complex, cis-Ru(II)(4,4'-bis(4-tert-butylstyryl)-2,2'-bipyridyl) (4,4'-dicarboxy-2,2'-bipyridyl) (NCS2) (H112) was synthesized and characterized by 1H-NMR, MASS, Spectrofluorometer and UV-Vis spectroscopes. The photo-voltaic performance of the sensitizer was evaluated in Dye Sensitized Solar Cell (DSSC) under irradiation of AM 1.5 G solar light and the photovoltaic characteristics were compared with those of reference cells of HRS1 and N719 fabricated under comparable conditions. Compared to N719, H112 sensitizer showed enhanced molar extinction coefficient and relatively better monochromatic incident photon-to-current conversion efficiency (IPCE) across the spectral range of 400 to 800 nm with solar energy-to-electrical conversion efficiency () of 2.43% [open circuit photovoltage (VOC) = 0.631V, short-circuit photocurrent density (JSC) = 8.96 mA/cm2, fill factor (ff) = 0.430], while values of 2.51% (VOC = 0.651V, JSC = 9.41 mA/cm2, ff = 0.410) and 2.74% (VOC = 0.705 V, JSC = 8.62 mA/cm2, ff = 0.455) were obtained for HRS1 and N719 sensitized solar cells respectively. The introduction of 4,4'-bis(4-tert-butylstyryl) moieties on one of the bipyridine moieties of N719 complex shows higher light absorption abilities, IPCE and JSC.

  4. Evaluation of a High-Throughput Peptide Reactivity Format Assay for Assessment of the Skin Sensitization Potential of Chemicals

    Science.gov (United States)

    Wong, Chin Lin; Lam, Ai-Leen; Smith, Maree T.; Ghassabian, Sussan

    2016-01-01

    The direct peptide reactivity assay (DPRA) is a validated method for in vitro assessment of the skin sensitization potential of chemicals. In the present work, we describe a peptide reactivity assay using 96-well plate format and systematically identified the optimal assay conditions for accurate and reproducible classification of chemicals with known sensitizing capacity. The aim of the research is to ensure that the analytical component of the peptide reactivity assay is robust, accurate, and reproducible in accordance with criteria that are used for the validation of bioanalytical methods. Analytical performance was evaluated using quality control samples (QCs; heptapeptides at low, medium, and high concentrations) and incubation of control chemicals (chemicals with known sensitization capacity, weak, moderate, strong, extreme, and non-sensitizers) with each of three synthetic heptapeptides, viz Cor1-C420 (Ac-NKKCDLF), cysteine- (Ac-RFAACAA), and lysine- (Ac-RFAAKAA) containing heptapeptides. The optimal incubation temperature for all three heptapeptides was 25°C. Apparent heptapeptide depletion was affected by vial material composition. Incubation of test chemicals with Cor1-C420, showed that peptide depletion was unchanged in polypropylene vials over 3-days storage in an autosampler but this was not the case for borosilicate glass vials. For cysteine-containing heptapeptide, the concentration was not stable by day 3 post-incubation in borosilicate glass vials. Although the lysine-containing heptapeptide concentration was unchanged in both polypropylene and borosilicate glass vials, the apparent extent of lysine-containing heptapeptide depletion by ethyl acrylate, differed between polypropylene (24.7%) and glass (47.3%) vials. Additionally, the peptide-chemical complexes for Cor1-C420-cinnamaldehyde and cysteine-containing heptapeptide-2, 4-dinitrochlorobenzene were partially reversible during 3-days of autosampler storage. These observations further highlight

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Chonglin; Nash, Patrick; Ma, Chunrui; Enriquez, Erik; Wang, Haibing; Xu, Xing; Bao, Shangyong; Collins, Gregory

    2013-08-13

    The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo{sub 2}O{sub 5+d} (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

  6. A high-sensitivity push-pull magnetometer

    Science.gov (United States)

    Breschi, E.; Grujić, Z. D.; Knowles, P.; Weis, A.

    2014-01-01

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/√Hz , using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/√Hz .

  7. A high-sensitivity push-pull magnetometer

    CERN Document Server

    Breschi, E; Knowles, P; Weis, A

    2013-01-01

    We describe our approach to atomic magnetometry based on the push-pull optical pumping technique. Cesium vapor is pumped and probed by a resonant laser beam whose circular polarization is modulated synchronously with the spin evolution dynamics induced by a static magnetic field. The magnetometer is operated in a phase-locked loop, and it has an intrinsic sensitivity below 20fT/\\sqrt(Hz) using a room temperature paraffin-coated cell. We use the magnetometer to monitor magnetic field fluctuations with a sensitivity of 300fT/\\sqrt(Hz).

  8. High Sensitivity SPECT for Small Animals and Plants

    Energy Technology Data Exchange (ETDEWEB)

    Mitchell, Gregory S. [UC Davis

    2015-02-28

    Imaging systems using single gamma-ray emitting radioisotopes typically implement collimators in order to form the images. However, a tradeoff in sensitivity is inherent in the use of collimators, and modern preclinical single-photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma-rays (<0.3%). We have built a collimator-less system, which can reach sensitivity of 40% for 99mTc imaging, while still producing images of sufficient spatial resolution for certain applications in thin objects such as mice, small plants, and well plates used for in vitro experiments.

  9. The effect of material composition of 3-dimensional graphene oxide and self-doped polyaniline nanocomposites on DNA analytical sensitivity.

    Science.gov (United States)

    Yang, Tao; Chen, Huaiyin; Yang, Ruirui; Wang, Xinxing; Nan, Fuxin; Jiao, Kui

    2015-09-01

    Until now, morphology effects of 2-dimensional or 3-dimensional graphene nanocomposites and the effect of material composition on the biosensors have been rarely reported. In this paper, the various nanocomposites based on graphene oxide and self-doped polyaniline nanofibres for studying the effect of morphology and material composition on DNA sensitivity were directly reported. The isolation and dispersion of graphene oxide were realized via intercalated self-doped polyaniline and ultrasonication, where the ultrasonication prompts the aggregates of graphite oxide to break up and self-doped polyaniline to diffuse into the stacked graphene oxide. Significant electrochemical enhancement has been observed due to the existence of self-doped polyaniline, which bridges the defects for electron transfer and, in the mean time, increases the basal spacing between graphene oxide sheets. Different morphologies can result in different ssDNA surface density, which can further influence the hybridization efficiency. Compared with 2-dimensional graphene oxide, self-doped polyaniline and other morphologies of nanocomposites, 3-dimensional graphene oxide-self-doped polyaniline nanowalls exhibited the highest surface density and hybridization efficiency. Furthermore, the fabricated biosensors presented the broad detection range with the low detection limit due to the specific surface area, a large number of electroactive species, and open accessible space supported by nanowalls.

  10. High sensitivity automated multiplexed immunoassays using photonic crystal enhanced fluorescence microfluidic system.

    Science.gov (United States)

    Tan, Yafang; Tang, Tiantian; Xu, Haisheng; Zhu, Chenqi; Cunningham, Brian T

    2015-11-15

    We demonstrate a platform that integrates photonic crystal enhanced fluorescence (PCEF) detection of a surface-based microspot fluorescent assay with a microfluidic cartridge to achieve simultaneous goals of high analytic sensitivity (single digit pg/mL), high selectivity, low sample volume, and assay automation. The PC surface, designed to provide optical resonances for the excitation wavelength and emission wavelength of Cyanines 5 (Cy5), was used to amplify the fluorescence signal intensity measured from a multiplexed biomarker microarray. The assay system is comprised of a plastic microfluidic cartridge for holding the PC and an assay automation system that provides a leak-free fluid interface during introduction of a sequence of fluids under computer control. Through the use of the assay automation system and the PC embedded within the microfluidic cartridge, we demonstrate pg/mL-level limits of detection by performing representative biomarker assays for interleukin 3 (IL3) and Tumor Necrosis Factor (TNF-α). The results are consistent with limits of detection achieved without the use of the microfluidic device with the exception that coefficients of variability from spot-to-spot are substantially lower than those obtained by performing assays with manual manipulation of assay liquids. The system's capabilities are compatible with the goal of diagnostic instruments for point-of-care settings.

  11. Analytical and Clinical Validation of a Digital Sequencing Panel for Quantitative, Highly Accurate Evaluation of Cell-Free Circulating Tumor DNA.

    Directory of Open Access Journals (Sweden)

    Richard B Lanman

    Full Text Available Next-generation sequencing of cell-free circulating solid tumor DNA addresses two challenges in contemporary cancer care. First this method of massively parallel and deep sequencing enables assessment of a comprehensive panel of genomic targets from a single sample, and second, it obviates the need for repeat invasive tissue biopsies. Digital Sequencing™ is a novel method for high-quality sequencing of circulating tumor DNA simultaneously across a comprehensive panel of over 50 cancer-related genes with a simple blood test. Here we report the analytic and clinical validation of the gene panel. Analytic sensitivity down to 0.1% mutant allele fraction is demonstrated via serial dilution studies of known samples. Near-perfect analytic specificity (> 99.9999% enables complete coverage of many genes without the false positives typically seen with traditional sequencing assays at mutant allele frequencies or fractions below 5%. We compared digital sequencing of plasma-derived cell-free DNA to tissue-based sequencing on 165 consecutive matched samples from five outside centers in patients with stage III-IV solid tumor cancers. Clinical sensitivity of plasma-derived NGS was 85.0%, comparable to 80.7% sensitivity for tissue. The assay success rate on 1,000 consecutive samples in clinical practice was 99.8%. Digital sequencing of plasma-derived DNA is indicated in advanced cancer patients to prevent repeated invasive biopsies when the initial biopsy is inadequate, unobtainable for genomic testing, or uninformative, or when the patient's cancer has progressed despite treatment. Its clinical utility is derived from reduction in the costs, complications and delays associated with invasive tissue biopsies for genomic testing.

  12. Analytical and Clinical Validation of a Digital Sequencing Panel for Quantitative, Highly Accurate Evaluation of Cell-Free Circulating Tumor DNA

    Science.gov (United States)

    Zill, Oliver A.; Sebisanovic, Dragan; Lopez, Rene; Blau, Sibel; Collisson, Eric A.; Divers, Stephen G.; Hoon, Dave S. B.; Kopetz, E. Scott; Lee, Jeeyun; Nikolinakos, Petros G.; Baca, Arthur M.; Kermani, Bahram G.; Eltoukhy, Helmy; Talasaz, AmirAli

    2015-01-01

    Next-generation sequencing of cell-free circulating solid tumor DNA addresses two challenges in contemporary cancer care. First this method of massively parallel and deep sequencing enables assessment of a comprehensive panel of genomic targets from a single sample, and second, it obviates the need for repeat invasive tissue biopsies. Digital SequencingTM is a novel method for high-quality sequencing of circulating tumor DNA simultaneously across a comprehensive panel of over 50 cancer-related genes with a simple blood test. Here we report the analytic and clinical validation of the gene panel. Analytic sensitivity down to 0.1% mutant allele fraction is demonstrated via serial dilution studies of known samples. Near-perfect analytic specificity (> 99.9999%) enables complete coverage of many genes without the false positives typically seen with traditional sequencing assays at mutant allele frequencies or fractions below 5%. We compared digital sequencing of plasma-derived cell-free DNA to tissue-based sequencing on 165 consecutive matched samples from five outside centers in patients with stage III-IV solid tumor cancers. Clinical sensitivity of plasma-derived NGS was 85.0%, comparable to 80.7% sensitivity for tissue. The assay success rate on 1,000 consecutive samples in clinical practice was 99.8%. Digital sequencing of plasma-derived DNA is indicated in advanced cancer patients to prevent repeated invasive biopsies when the initial biopsy is inadequate, unobtainable for genomic testing, or uninformative, or when the patient’s cancer has progressed despite treatment. Its clinical utility is derived from reduction in the costs, complications and delays associated with invasive tissue biopsies for genomic testing. PMID:26474073

  13. Analytical and Clinical Validation of a Digital Sequencing Panel for Quantitative, Highly Accurate Evaluation of Cell-Free Circulating Tumor DNA.

    Science.gov (United States)

    Lanman, Richard B; Mortimer, Stefanie A; Zill, Oliver A; Sebisanovic, Dragan; Lopez, Rene; Blau, Sibel; Collisson, Eric A; Divers, Stephen G; Hoon, Dave S B; Kopetz, E Scott; Lee, Jeeyun; Nikolinakos, Petros G; Baca, Arthur M; Kermani, Bahram G; Eltoukhy, Helmy; Talasaz, AmirAli

    2015-01-01

    Next-generation sequencing of cell-free circulating solid tumor DNA addresses two challenges in contemporary cancer care. First this method of massively parallel and deep sequencing enables assessment of a comprehensive panel of genomic targets from a single sample, and second, it obviates the need for repeat invasive tissue biopsies. Digital Sequencing™ is a novel method for high-quality sequencing of circulating tumor DNA simultaneously across a comprehensive panel of over 50 cancer-related genes with a simple blood test. Here we report the analytic and clinical validation of the gene panel. Analytic sensitivity down to 0.1% mutant allele fraction is demonstrated via serial dilution studies of known samples. Near-perfect analytic specificity (> 99.9999%) enables complete coverage of many genes without the false positives typically seen with traditional sequencing assays at mutant allele frequencies or fractions below 5%. We compared digital sequencing of plasma-derived cell-free DNA to tissue-based sequencing on 165 consecutive matched samples from five outside centers in patients with stage III-IV solid tumor cancers. Clinical sensitivity of plasma-derived NGS was 85.0%, comparable to 80.7% sensitivity for tissue. The assay success rate on 1,000 consecutive samples in clinical practice was 99.8%. Digital sequencing of plasma-derived DNA is indicated in advanced cancer patients to prevent repeated invasive biopsies when the initial biopsy is inadequate, unobtainable for genomic testing, or uninformative, or when the patient's cancer has progressed despite treatment. Its clinical utility is derived from reduction in the costs, complications and delays associated with invasive tissue biopsies for genomic testing.

  14. High-speed high-sensitivity infrared spectroscopy using mid-infrared swept lasers (Conference Presentation)

    Science.gov (United States)

    Childs, David T. D.; Groom, Kristian M.; Hogg, Richard A.; Revin, Dmitry G.; Cockburn, John W.; Rehman, Ihtesham U.; Matcher, Stephen J.

    2016-03-01

    Infrared spectroscopy is a highly attractive read-out technology for compositional analysis of biomedical specimens because of its unique combination of high molecular sensitivity without the need for exogenous labels. Traditional techniques such as FTIR and Raman have suffered from comparatively low speed and sensitivity however recent innovations are challenging this situation. Direct mid-IR spectroscopy is being speeded up by innovations such as MEMS-based FTIR instruments with very high mirror speeds and supercontinuum sources producing very high sample irradiation levels. Here we explore another possible method - external cavity quantum cascade lasers (EC-QCL's) with high cavity tuning speeds (mid-IR swept lasers). Swept lasers have been heavily developed in the near-infrared where they are used for non-destructive low-coherence imaging (OCT). We adapt these concepts in two ways. Firstly by combining mid-IR quantum cascade gain chips with external cavity designs adapted from OCT we achieve spectral acquisition rates approaching 1 kHz and demonstrate potential to reach 100 kHz. Secondly we show that mid-IR swept lasers share a fundamental sensitivity advantage with near-IR OCT swept lasers. This makes them potentially able to achieve the same spectral SNR as an FTIR instrument in a time x N shorter (N being the number of spectral points) under otherwise matched conditions. This effect is demonstrated using measurements of a PDMS sample. The combination of potentially very high spectral acquisition rates, fundamental SNR advantage and the use of low-cost detector systems could make mid-IR swept lasers a powerful technology for high-throughput biomedical spectroscopy.

  15. Cavity Enhanced Optical Vernier Spectroscopy, Broad Band, High Resolution, High Sensitivity

    CERN Document Server

    Gohle, Christoph; Schliesser, Albert; Udem, Thomas; Hänsch, Theodor W

    2007-01-01

    A femtosecond frequency comb provides a vast number of equidistantly spaced narrow band laser modes that can be simultaneously tuned and frequency calibrated with 15 digits accuracy. Our Vernier spectrometer utilizes all of theses modes in a massively parallel manner to rapidly record both absorption and dispersion spectra with a sensitivity that is provided by a high finesse broad band optical resonator and a resolution that is only limited by the frequency comb line width while keeping the required setup simple.

  16. Pajarito Monitor: a high-sensitivity monitoring system for highly enriched uranium

    Energy Technology Data Exchange (ETDEWEB)

    Fehlau, P.E.; Coop, K.; Garcia, C. Jr.; Martinez, J.

    1984-01-01

    The Pajarito Monitor for Special Nuclear Material is a high-sensitivity gamma-ray monitoring system for detecting small quantities of highly enriched uranium transported by pedestrians or motor vehicles. The monitor consists of two components: a walk-through personnel monitor and a vehicle monitor. The personnel monitor has a plastic-scintillator detector portal, a microwave occupancy monitor, and a microprocessor control unit that measures the radiation intensity during background and monitoring periods to detect transient diversion signals. The vehicle monitor examines stationary motor vehicles while the vehicle's occupants pass through the personnel portal to exchange their badges. The vehicle monitor has four groups of large plastic scintillators that scan the vehicle from above and below. Its microprocessor control unit measures separate radiation intensities in each detector group. Vehicle occupancy is sensed by a highway traffic detection system. Each monitor's controller is responsible for detecting diversion as well as serving as a calibration and trouble-shooting aid. Diversion signals are detected by a sequential probability ratio hypothesis test that minimizes the monitoring time in the vehicle monitor and adapts itself well to variations in individual passage speed in the personnel monitor. Designed to be highly sensitive to diverted enriched uranium, the monitoring system also exhibits exceptional sensitivity for plutonium. 6 references, 9 figures, 2 tables.

  17. Cisapride a green analytical reagent for rapid and sensitive determination of bromate in drinking water, bread and flour additives by oxidative coupling spectrophotometric methods

    Science.gov (United States)

    Al Okab, Riyad Ahmed

    2013-02-01

    Green analytical methods using Cisapride (CPE) as green analytical reagent was investigated in this work. Rapid, simple, and sensitive spectrophotometric methods for the determination of bromate in water sample, bread and flour additives were developed. The proposed methods based on the oxidative coupling between phenoxazine and Cisapride in the presence of bromate to form red colored product with max at 520 nm. Phenoxazine and Cisapride and its reaction products were found to be environmentally friendly under the optimum experimental condition. The method obeys beers law in concentration range 0.11-4.00 g ml-1 and molar absorptivity 1.41 × 104 L mol-1 cm-1. All variables have been optimized and the presented reaction sequences were applied to the analysis of bromate in water, bread and flour additive samples. The performance of these method was evaluated in terms of Student's t-test and variance ratio F-test to find out the significance of proposed methods over the reference method. The combination of pharmaceutical drugs reagents with low concentration create some unique green chemical analyses.

  18. Highly sensitive and selective analysis of widely targeted metabolomics using gas chromatography/triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Tsugawa, Hiroshi; Tsujimoto, Yuki; Sugitate, Kuniyo; Sakui, Norihiro; Nishiumi, Shin; Bamba, Takeshi; Fukusaki, Eiichiro

    2014-01-01

    In metabolomics studies, gas chromatography coupled with time-of-flight or quadrupole mass spectrometry has frequently been used for the non-targeted analysis of hydrophilic metabolites. However, because the analytical platform employs the deconvolution method to extract single-metabolite information from co-eluted peaks and background noise, the extracted peak is artificial product depending on the mathematical parameters and is not completely compatible with the pure component obtained by analyzing a standard compound. Moreover, it has insufficient ability for quantitative metabolomics. Therefore, highly sensitive and selective methods capable of pure peak extraction without any complicated mathematical techniques are needed. For this purpose, we have developed a novel analytical method using gas chromatography coupled with triple-quadrupole mass spectrometry (GC-QqQ/MS). We developed a selected reaction monitoring (SRM) method to analyze the trimethylsilyl derivatives of 110 metabolites, using electron ionization. This methodology enables us to utilize two complementary techniques-non-targeted and widely targeted metabolomics in the same sample preparation protocol, which would facilitate the formulation or verification of novel hypotheses in biological sciences. The GC-QqQ/MS analysis can accurately identify a metabolite using multichannel SRM transitions and intensity ratios in the analysis of living organisms. In addition, our methodology offers a wide dynamic range, high sensitivity, and highly reproducible metabolite profiles, which will contribute to the biomarker discoveries and quality evaluations in biology, medicine, and food sciences.

  19. Ship Classification with High Resolution TerraSAR-X Imagery Based on Analytic Hierarchy Process

    Directory of Open Access Journals (Sweden)

    Zhi Zhao

    2013-01-01

    Full Text Available Ship surveillance using space-borne synthetic aperture radar (SAR, taking advantages of high resolution over wide swaths and all-weather working capability, has attracted worldwide attention. Recent activity in this field has concentrated mainly on the study of ship detection, but the classification is largely still open. In this paper, we propose a novel ship classification scheme based on analytic hierarchy process (AHP in order to achieve better performance. The main idea is to apply AHP on both feature selection and classification decision. On one hand, the AHP based feature selection constructs a selection decision problem based on several feature evaluation measures (e.g., discriminability, stability, and information measure and provides objective criteria to make comprehensive decisions for their combinations quantitatively. On the other hand, we take the selected feature sets as the input of KNN classifiers and fuse the multiple classification results based on AHP, in which the feature sets’ confidence is taken into account when the AHP based classification decision is made. We analyze the proposed classification scheme and demonstrate its results on a ship dataset that comes from TerraSAR-X SAR images.

  20. Shallow groundwater thermal sensitivity to climate change and land cover disturbances: derivation of analytical expressions and implications for stream temperature projections

    Directory of Open Access Journals (Sweden)

    B. L. Kurylyk

    2014-11-01

    Full Text Available Climate change is expected to increase stream temperatures, and the projected warming may alter the spatial extent of habitat for coldwater fish and other aquatic taxa. Recent studies have proposed that stream thermal sensitivities, derived from short term air temperature variations, can be employed to infer future stream warming due to long term climate change. However, this approach does not consider the potential for streambed heat fluxes to increase due to gradual warming of shallow groundwater. The temperature of shallow groundwater is particularly important for the thermal regimes of groundwater-dominated streams and rivers. Also, other recent stream temperature studies have investigated how land surface perturbations, such as wildfires or timber harvesting, can influence stream temperatures by changing surface heat fluxes, but these studies have typically not considered how these surface disturbances can also alter shallow groundwater temperatures and consequent streambed heat fluxes. In this study, several analytical solutions to the one-dimensional unsteady advection–diffusion equation for subsurface heat transport are employed to investigate the timing and magnitude of groundwater warming due to seasonal and long term variability in land surface temperatures. Novel groundwater thermal sensitivity formulae are proposed that accommodate different surface warming scenarios. The thermal sensitivity formulae demonstrate that shallow groundwater will warm in response to climate change and other surface perturbations, but the timing and magnitude of the warming depends on the rate of surface warming, subsurface thermal properties, aquifer depth, and groundwater velocity. The results also emphasize the difference between the thermal sensitivity of shallow groundwater to short term (e.g. seasonal and long term (e.g. multi-decadal land surface temperature variability, and thus demonstrate the limitations of using short term air and water

  1. Desensitization protocol in highly HLA-sensitized and ABO-incompatible high titer kidney transplantation.

    Science.gov (United States)

    Uchida, J; Machida, Y; Iwai, T; Naganuma, T; Kitamoto, K; Iguchi, T; Maeda, S; Kamada, Y; Kuwabara, N; Kim, T; Nakatani, T

    2010-12-01

    A positive crossmatch indicates the presence of donor-specific alloantibodies and is associated with a graft loss rate of >80%; anti-ABO blood group antibodies develop in response to exposure to foreign blood groups, resulting in immediate graft loss. However, a desensitization protocol for highly HLA-sensitized and ABO-incompatible high-titer kidney transplantation has not yet been established. We treated 6 patients with high (≥1:512) anti-A/B antibody titers and 2 highly HLA-sensitized patients. Our immunosuppression protocol was initiated 1 month before surgery and included mycophenolate mofetil (1 g/d) and/or low-dose steroid (methylprednisolone 8 mg/d). Two doses of the anti-CD20 antibody rituximab (150 mg/m(2)) were administered 2 weeks before and on the day of transplantation. We performed antibody removal with 6-12 sessions of plasmapheresis (plasma exchange or double-filtration plasmapheresis) before transplantation. Splenectomy was also performed on the day of transplantation. Postoperative immunosuppression followed the same regimen as ABO-compatible cases, in which calcineurin inhibitors were initiated 3 days before transplantation, combined with 2 doses of basiliximab. Of the 8 patients, 7 subsequently underwent successful living-donor kidney transplantation. Follow-up of our recipients showed that the patient and graft survival rates were 100%. Acute cellular rejection and antibody-mediated rejection episodes occurred in 1 of the 7 recipients. These findings suggest that our immunosuppression regimen consisting of rituximab infusions, splenectomy, plasmapheresis, and pharmacologic immunosuppression may prove to be effective as a desensitization protocol for highly HLA-sensitized and ABO-incompatible high-titer kidney transplantation. Copyright © 2010 Elsevier Inc. All rights reserved.

  2. Temperature insensitive hysteresis free highly sensitive polymer optical fiber Bragg grating humidity sensor

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Nielsen, Kristian; Stefani, Alessio

    2016-01-01

    sensitivity and a high hysteresis in the humidity response, in particular when operated at high temperature. PMMA mPOFBGs annealed at high humidity show higher and more linear humidity sensitivity with negligible hysteresis. We also report how annealing at high humidity can blue-shift the FBG wavelength more...

  3. Architectural Considerations for Highly Scalable Computing to Support On-demand Video Analytics

    Science.gov (United States)

    2017-04-19

    be passed on to multiple operating systems of choice (windows or Linux ) in a uniform fashion. This helps in running analytics on multiple OS’s. A...common share between windows and Linux nodes. Another implementation detail is that the algorithm processing part of an analytics must run to...shared storage was made available to windows nodes as \\\\sigmafs\\data CIFS share and to Linux nodes as /sigmafs/data NFS mount point. VI. CONCLUSION

  4. Analytical Modeling of the High Strain Rate Deformation of Polymer Matrix Composites

    Science.gov (United States)

    Goldberg, Robert K.; Roberts, Gary D.; Gilat, Amos

    2003-01-01

    The results presented here are part of an ongoing research program to develop strain rate dependent deformation and failure models for the analysis of polymer matrix composites subject to high strain rate impact loads. State variable constitutive equations originally developed for metals have been modified in order to model the nonlinear, strain rate dependent deformation of polymeric matrix materials. To account for the effects of hydrostatic stresses, which are significant in polymers, the classical 5 plasticity theory definitions of effective stress and effective plastic strain are modified by applying variations of the Drucker-Prager yield criterion. To verify the revised formulation, the shear and tensile deformation of a representative toughened epoxy is analyzed across a wide range of strain rates (from quasi-static to high strain rates) and the results are compared to experimentally obtained values. For the analyzed polymers, both the tensile and shear stress-strain curves computed using the analytical model correlate well with values obtained through experimental tests. The polymer constitutive equations are implemented within a strength of materials based micromechanics method to predict the nonlinear, strain rate dependent deformation of polymer matrix composites. In the micromechanics, the unit cell is divided up into a number of independently analyzed slices, and laminate theory is then applied to obtain the effective deformation of the unit cell. The composite mechanics are verified by analyzing the deformation of a representative polymer matrix composite (composed using the representative polymer analyzed for the correlation of the polymer constitutive equations) for several fiber orientation angles across a variety of strain rates. The computed values compare favorably to experimentally obtained results.

  5. Evaluation of an analytic linear Boltzmann transport equation solver for high-density inhomogeneities

    Energy Technology Data Exchange (ETDEWEB)

    Lloyd, S. A. M.; Ansbacher, W. [Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada); Department of Physics and Astronomy, University of Victoria, Victoria, British Columbia V8W 3P6 (Canada) and Department of Medical Physics, British Columbia Cancer Agency-Vancouver Island Centre, Victoria, British Columbia V8R 6V5 (Canada)

    2013-01-15

    Purpose: Acuros external beam (Acuros XB) is a novel dose calculation algorithm implemented through the ECLIPSE treatment planning system. The algorithm finds a deterministic solution to the linear Boltzmann transport equation, the same equation commonly solved stochastically by Monte Carlo methods. This work is an evaluation of Acuros XB, by comparison with Monte Carlo, for dose calculation applications involving high-density materials. Existing non-Monte Carlo clinical dose calculation algorithms, such as the analytic anisotropic algorithm (AAA), do not accurately model dose perturbations due to increased electron scatter within high-density volumes. Methods: Acuros XB, AAA, and EGSnrc based Monte Carlo are used to calculate dose distributions from 18 MV and 6 MV photon beams delivered to a cubic water phantom containing a rectangular high density (4.0-8.0 g/cm{sup 3}) volume at its center. The algorithms are also used to recalculate a clinical prostate treatment plan involving a unilateral hip prosthesis, originally evaluated using AAA. These results are compared graphically and numerically using gamma-index analysis. Radio-chromic film measurements are presented to augment Monte Carlo and Acuros XB dose perturbation data. Results: Using a 2% and 1 mm gamma-analysis, between 91.3% and 96.8% of Acuros XB dose voxels containing greater than 50% the normalized dose were in agreement with Monte Carlo data for virtual phantoms involving 18 MV and 6 MV photons, stainless steel and titanium alloy implants and for on-axis and oblique field delivery. A similar gamma-analysis of AAA against Monte Carlo data showed between 80.8% and 87.3% agreement. Comparing Acuros XB and AAA evaluations of a clinical prostate patient plan involving a unilateral hip prosthesis, Acuros XB showed good overall agreement with Monte Carlo while AAA underestimated dose on the upstream medial surface of the prosthesis due to electron scatter from the high-density material. Film measurements

  6. Highly sensitive BTX detection using surface functionalized QCM sensor

    Energy Technology Data Exchange (ETDEWEB)

    Bozkurt, Asuman Aşıkoğlu; Özdemir, Okan; Altındal, Ahmet, E-mail: altindal@yildiz.edu.tr [Department of Physics, Yildiz Technical University, Davutpasa, 34210 Istanbul (Turkey)

    2016-03-25

    A novel organic compound was designed and successfully synthesized for the fabrication of QCM based sensors to detect the low concentrations of BTX gases in indoor air. The effect of the long-range electron orbital delocalization on the BTX vapour sensing properties of azo-bridged Pcs based chemiresistor-type sensors have also been investigated in this work. The sensing behaviour of the film for the online detection of volatile organic solvent vapors was investigated by utilizing an AT-cut quartz crystal resonator. It was observed that the adsorption of the target molecules on the coating surface cause a reversible negative frequency shift of the resonator. Thus, a variety of solvent vapors can be detected by using the phthalocyanine film as sensitive coating, with sensitivity in the ppm range and response times in the order of several seconds depending on the molecular structure of the organic solvent.

  7. Highly Sensitive Cadmium Concentration Sensor Using Long Period Grating

    Directory of Open Access Journals (Sweden)

    A. S. Lalasangi

    2011-08-01

    Full Text Available In this paper we have proposed a simple and effective Long Period Grating chemical sensor for detecting the traces of Cadmium (Cd++ in drinking water at ppm level. Long Period gratings (LPG were fabricated by point-by-point technique with CO2 laser. We have characterized the LPG concentration sensor sensitivity for different solutions of Cd concentrations varying from 0.01 ppm to 0.04 ppm by injecting white Light source and observed transmitted spectra using Optical Spectrum Analyzer (OSA. Proper reagents have been used in the solutions for detection of the Cd species. The overall shift in wavelength is 10 nm when surrounding medium gradually changed from water to 0.04 ppm of cadmium concentrations. A comparative study has been done using sophisticated spectroscopic atomic absorption spectrometer (AAS and Inductively Coupled Plasma (ICP instruments. The spectral sensitivity enhancement was done by modifying grating surface with gold nanoparticles.

  8. Highly sensitive detection using Herriott cell for laser absorption spectroscopy

    Science.gov (United States)

    Zhao, Chongyi; Song, Guangming; Du, Yang; Zhao, Xiaojun; Wang, Wenju; Zhong, Liujun; Hu, Mai

    2016-11-01

    The tunable diode laser absorption spectroscopy combined with the long absorption path technique is a significant method to detect harmful gas. The long optical path could come true by Herriott cell reducing the size of the spectrometers. A 15 cm long Herriott cell with 28.8 m optical absorption path after 96 times reflection was designed that enhanced detection sensitivity of absorption spectroscopy. According to the theory data of calculation, Herriott cell is analyzed and simulated by softwares Matlab and Lighttools.

  9. HIGH SENSITIVE C-REACTIVE PROTEIN IN CEREBROVASCULAR ISCHEMIA

    OpenAIRE

    Padmalatha; Neeraja

    2016-01-01

    BACKGROUND Cerebrovascular ischemia is recognized as a major health problem, which causes significant morbidity and mortality. The main pathophysiology of ischemic stroke is atherosclerosis of cerebral vessels. Hs-CRP is a sensitive marker of inflammation tissue injury in the arterial wall, which contributes to atherosclerosis. In this study, we aim to investigate the association of hs-CRP in patients with ischemic stroke and to correlate hs-CRP levels with possible risk facto...

  10. The strain-rate sensitivity of high-strength high-toughness steels.

    Energy Technology Data Exchange (ETDEWEB)

    Dilmore, M.F. (AFRL/MNMW, Eglin AFB, FL); Crenshaw, Thomas B.; Boyce, Brad Lee

    2006-01-01

    The present study examines the strain-rate sensitivity of four high strength, high-toughness alloys at strain rates ranging from 0.0002 s-1 to 200 s-1: Aermet 100, a modified 4340, modified HP9-4-20, and a recently developed Eglin AFB steel alloy, ES-1c. A refined dynamic servohydraulic method was used to perform tensile tests over this entire range. Each of these alloys exhibit only modest strain-rate sensitivity. Specifically, the strain-rate sensitivity exponent m, is found to be in the range of 0.004-0.007 depending on the alloy. This corresponds to a {approx}10% increase in the yield strength over the 7-orders of magnitude change in strain-rate. Interestingly, while three of the alloys showed a concominant {approx}3-10% drop in their ductility with increasing strain-rate, the ES1-c alloy actually exhibited a 25% increase in ductility with increasing strain-rate. Fractography suggests the possibility that at higher strain-rates ES-1c evolves towards a more ductile dimple fracture mode associated with microvoid coalescence.

  11. Antibody desensitization therapy in highly sensitized lung transplant candidates.

    Science.gov (United States)

    Snyder, L D; Gray, A L; Reynolds, J M; Arepally, G M; Bedoya, A; Hartwig, M G; Davis, R D; Lopes, K E; Wegner, W E; Chen, D F; Palmer, S M

    2014-04-01

    As HLAs antibody detection technology has evolved, there is now detailed HLA antibody information available on prospective transplant recipients. Determining single antigen antibody specificity allows for a calculated panel reactive antibodies (cPRA) value, providing an estimate of the effective donor pool. For broadly sensitized lung transplant candidates (cPRA ≥ 80%), our center adopted a pretransplant multi-modal desensitization protocol in an effort to decrease the cPRA and expand the donor pool. This desensitization protocol included plasmapheresis, solumedrol, bortezomib and rituximab given in combination over 19 days followed by intravenous immunoglobulin. Eight of 18 candidates completed therapy with the primary reasons for early discontinuation being transplant (by avoiding unacceptable antigens) or thrombocytopenia. In a mixed-model analysis, there were no significant changes in PRA or cPRA changes over time with the protocol. A sub-analysis of the median fluorescence intensity (MFI) change indicated a small decline that was significant in antibodies with MFI 5000-10,000. Nine of 18 candidates subsequently had a transplant. Posttransplant survival in these nine recipients was comparable to other pretransplant-sensitized recipients who did not receive therapy. In summary, an aggressive multi-modal desensitization protocol does not significantly reduce pretransplant HLA antibodies in a broadly sensitized lung transplant candidate cohort. © Copyright 2014 The American Society of Transplantation and the American Society of Transplant Surgeons.

  12. Development, optimization and validation of a sub-minute analytical enantioselective high performance liquid chromatographic separation for a folic acid precursor in normal phase mode.

    Science.gov (United States)

    Frühauf, Doris; Juza, Markus

    2012-12-21

    A sub-minute enantioselective normal phase high performance liquid chromatographic (HPLC) method for the analysis of a chiral precursor molecule employed frequently in folic acid syntheses was developed, optimized and successfully validated according to ICH-guidelines. It could be shown that ultra-high performance chromatography (UHPLC) can give significant advantages compared to traditional HPLC not only in reversed phase HPLC, but also for enantioselective separations in normal phase mode. Novel 3 μm-particle sizes allow developing analytical chromatographic methods completely resolving two enantiomers in the shortest time possible while preserving high efficiency and low detection limits. By offering increased resolution, sensitivity and speed, enantioselective UHPLC (eUHPLC) improves sample throughput, productivity and provides considerably faster access to information on enantiomeric purity also under non-aqueous conditions.

  13. Ion suppression and enhancement effects of co-eluting analytes in multi-analyte approaches: systematic investigation using ultra-high-performance liquid chromatography/mass spectrometry with atmospheric-pressure chemical ionization or electrospray ionization.

    Science.gov (United States)

    Remane, Daniela; Meyer, Markus R; Wissenbach, Dirk K; Maurer, Hans H

    2010-11-15

    In multi-analyte procedures, sufficient separation is important to avoid interferences, particularly when using liquid chromatography/mass spectrometry (LC/MS) because of possible ion suppression or enhancement. However, even using ultra-high-performance LC, baseline separation is not always possible. For development and validation of an LC/MS/MS approach for quantification of 140 antidepressants, benzodiazepines, neuroleptics, beta-blockers, oral antidiabetics, and analytes measured in the context of brain death diagnosis in plasma, the extent of ion suppression or enhancement of co-eluting analytes within and between the drug classes was investigated using atmospheric-pressure chemical ionization (APCI) or electrospray ionization (ESI). Within the drug classes, five analytes showed ion enhancement of over 25% and six analytes ion suppression of over 25% using APCI and 16 analytes ion suppression of over 25% using ESI. Between the drug classes, two analytes showed ion suppression of over 25% using APCI. Using ESI, one analyte showed ion enhancement of over 25% and five analytes ion suppression of over 25%. These effects may influence the drug quantification using calibrators made in presence of overlapping and thus interfering analytes. Ion suppression/enhancement effects induced by co-eluting drugs of different classes present in the patient sample may also lead to false measurements using class-specific calibrators made in absence of overlapping and thus interfering analytes. In conclusion, ion suppression and enhancement tests are essential during method development and validation in LC/MS/MS multi-analyte procedures, with special regards to co-eluting analytes.

  14. High-performance and high-sensitivity applications of graphene transistors with self-assembled monolayers.

    Science.gov (United States)

    Yeh, Chao-Hui; Kumar, Vinod; Moyano, David Ricardo; Wen, Shao-Hsuan; Parashar, Vyom; Hsiao, She-Hsin; Srivastava, Anchal; Saxena, Preeti S; Huang, Kun-Ping; Chang, Chien-Chung; Chiu, Po-Wen

    2016-03-15

    Charge impurities and polar molecules on the surface of dielectric substrates has long been a critical obstacle to using graphene for its niche applications that involve graphene's high mobility and high sensitivity nature. Self-assembled monolayers (SAMs) have been found to effectively reduce the impact of long-range scatterings induced by the external charges. Yet, demonstrations of scalable device applications using the SAMs technique remains missing due to the difficulties in the device fabrication arising from the strong surface tension of the modified dielectric environment. Here, we use patterned SAM arrays to build graphene electronic devices with transport channels confined on the modified areas. For high-mobility applications, both rigid and flexible radio-frequency graphene field-effect transistors (G-FETs) were demonstrated, with extrinsic cutoff frequency and maximum oscillation frequency enhanced by a factor of ~2 on SiO2/Si substrates. For high sensitivity applications, G-FETs were functionalized by monoclonal antibodies specific to cancer biomarker chondroitin sulfate proteoglycan 4, enabling its detection at a concentration of 0.01 fM, five orders of magnitude lower than that detectable by a conventional colorimetric assay. These devices can be very useful in the early diagnosis and monitoring of a malignant disease.

  15. Fabrication of highly sensitive gold nanourchins based electrochemical sensor for nanomolar determination of primaquine.

    Science.gov (United States)

    Thapliyal, Neeta Bachheti; Chiwunze, Tirivashe Elton; Karpoormath, Rajshekhar; Cherukupalli, Srinivasulu

    2017-05-01

    A gold nanourchins modified glassy carbon electrode (AuNu/GCE) was developed for the determination of antimalarial drug, primaquine (PQ). The surface of AuNu/GCE was characterized by electrochemical impedance spectroscopy (EIS), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and cyclic voltammetry (CV). EIS results indicated that the electron transfer process at AuNu/GCE was faster as compared to the bare electrode. The SEM and TEM image confirmed the presence and uniform dispersion of gold nanourchins on the GCE surface. Upon investigating the electrochemical behavior of PQ at AuNu/GCE, the developed sensor was found to exhibit high electrocatalytic activity towards the oxidation of PQ. Under optimal experimental conditions, the sensor showed fast and sensitive current response to PQ over a linear concentration range of 0.01-1μM and 0.001-1μM with a detection limit of 3.5nM and 0.9nM using differential pulse voltammetry (DPV) and square wave voltammetry (SWV), respectively. The AuNu/GCE showed good selectivity, reproducibility and stability. Further, the developed sensor was successfully applied to determine the drug in human urine samples and pharmaceutical formulations demonstrating its analytical applicability in clinical analysis as well as quality control. The proposed method thus provides a promising alternative in routine sensing of PQ as well as promotes the application of gold nanourchins in electrochemical sensors. Copyright © 2017 Elsevier B.V. All rights reserved.

  16. Highly sensitive dual mode electrochemical platform for microRNA detection

    Science.gov (United States)

    Jolly, Pawan; Batistuti, Marina R.; Miodek, Anna; Zhurauski, Pavel; Mulato, Marcelo; Lindsay, Mark A.; Estrela, Pedro

    2016-11-01

    MicroRNAs (miRNAs) play crucial regulatory roles in various human diseases including cancer, making them promising biomarkers. However, given the low levels of miRNAs present in blood, their use as cancer biomarkers requires the development of simple and effective analytical methods. Herein, we report the development of a highly sensitive dual mode electrochemical platform for the detection of microRNAs. The platform was developed using peptide nucleic acids as probes on gold electrode surfaces to capture target miRNAs. A simple amplification strategy using gold nanoparticles has been employed exploiting the inherent charges of the nucleic acids. Electrochemical impedance spectroscopy was used to monitor the changes in capacitance upon any binding event, without the need for any redox markers. By using thiolated ferrocene, a complementary detection mode on the same sensor was developed where the increasing peaks of ferrocene were recorded using square wave voltammetry with increasing miRNA concentration. This dual-mode approach allows detection of miRNA with a limit of detection of 0.37 fM and a wide dynamic range from 1 fM to 100 nM along with clear distinction from mismatched target miRNA sequences. The electrochemical platform developed can be easily expanded to other miRNA/DNA detection along with the development of microarray platforms.

  17. Highly sensitive method for diagnosis of subclinical B. ovis infection.

    Science.gov (United States)

    Horta, Sara; Barreto, Maria C; Pepe, Ana; Campos, Joana; Oliva, Abel

    2014-10-01

    Babesia ovis is a tick-transmitted protozoa parasite that infects small ruminants causing fever, anaemia, hemoglobinuria, anorexia and, in acute cases, death. Common in tropical and sub-tropical areas, the presence of this parasite in sheep herds has an economic impact on industry and therefore sensitive methods for the diagnosis and disease eradication are required. To achieve this goal, a semi-nested PCR for B. ovis specific identification was developed and consequent reaction conditions and enzymes were optimized and tested with field samples. 300 blood samples from small ruminants and 39 ticks from Rhipicephalus genus were collected from different regions of Portugal. Afterwards, DNA extraction was performed and conventional and semi-nested PCR were accomplished for all samples. The results obtained from both methodologies were compared and the sensitivity was evaluated. Employing the semi-nested PCR it was possible to identify a higher number of positive cases among the evaluated samples than using the conventional PCR, namely 38/300 blood samples and 7/39 ticks. However, fragment amplification was only observed in 5 out of 300 blood samples and in none of the 39 ticks when a conventional PCR was employed. The validation of the results was achieved by sequencing the DNA fragments corresponding to the hypervariable v4 region of the 18S ribosomal RNA gene and performing an alignment with sequences already published on GenBank(®). The ticks collected in this study belong to the Rhipicephalus genus, although other species could be involved as a vector in the Babesia spread. The diagnostic assay here described is presently the most effective and sensitive method for detection of B. ovis in field blood samples and ticks, enabling the detection up to 1 parasite into 10(9) erythrocytes. Copyright © 2014 Elsevier GmbH. All rights reserved.

  18. Liquid-phase exfoliated graphene as highly-sensitive sensor for simultaneous determination of endocrine disruptors: Diethylstilbestrol and estradiol

    Energy Technology Data Exchange (ETDEWEB)

    Hu, Lintong; Cheng, Qin [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China); Chen, Danchao; Ma, Ming [Ningbo Entry-exit Inspection and Quarantine Bureau of China, Ningbo 315012 (China); Wu, Kangbing, E-mail: kbwu@hust.edu.cn [Key Laboratory for Large-Format Battery Materials and System, Ministry of Education, School of Chemistry and Chemical Engineering, Huazhong University of Science and Technology, Wuhan 430074 (China)

    2015-02-11

    Graphical abstract: - Highlights: • A novel electrochemical sensor was developed for diethylstilbestrol and estradiol. • Graphene prepared by solvent exfoliation greatly enhances the detection sensitivity. • The newly-developed method has promising application and the accuracy is good. - Abstract: It is quite important to develop convenient and rapid analytical methods for trace levels of endocrine disruptors because they heavily affect health and reproduction of humans and animals. Herein, graphene was easily prepared via one-step exfoliation using N-methyl-2-pyrrolidone as solvent, and then used to construct an electrochemical sensor for highly-sensitive detection of diethylstilbestrol (DES) and estradiol (E2). On the surface of prepared graphene film, two independent and greatly-increased oxidation waves were observed at 0.28 V and 0.49 V for DES and E2. The remarkable signal enlargements indicated that the detection sensitivity was improved significantly. The influences of pH value, amount of graphene and accumulation time on the oxidation signals of DES and E2 were discussed. As a result, a highly-sensitive and rapid electrochemical method was newly developed for simultaneous detection of DES and E2. The values of detection limit were evaluated to be 10.87 nM and 4.9 nM for DES and E2. Additionally, this new method was successfully used in lake water samples and the accuracy was satisfactory.

  19. HIGHLY SENSITIVE TIMER-BASED RESISTANCE DEVIATION TO TIME CONVERTER

    Directory of Open Access Journals (Sweden)

    Sheroz Khan

    2012-02-01

    Full Text Available Based on an inexpensive popular precision timing chip 555 timer, a resistance to time converter is proposed in this paper which is indeed capable of converting resistive and capacitive changes into pulse widths of proportional durations. This converter exhibits a compatibility of wider conversion range with a reasonable level of sensitivity required for industrial applications. The circuit is expected to have utility in oil and water supply schemes. Simulated results are shown to be compared with mathematical derivations, both reporting a good level of resemblance and similarities.

  20. High order sensitivity analysis of complex, coupled systems

    Science.gov (United States)

    Sobieszczanski-Sobieski, Jaroslaw

    1990-01-01

    The Sobieszczanski-Sobieski (1988) algorithm is extended to include second- and higher-order derivatives while retaining the obviation of finite-differencing of the system analysis. This is accomplished by means of a recursive application of the same implicit function theorem as in the original algorithm. In optimization, the computational cost of the higher-order derivatives is relative to the aggregate cost of analysis together with a repetition of the first-order sensitivity analysis as often as is required to produce the equivalent information by successive linearizations within move limits.

  1. Analysis of Cyberbullying Sensitivity Levels of High School Students and Their Perceived Social Support Levels

    Science.gov (United States)

    Akturk, Ahmet Oguz

    2015-01-01

    Purpose: The purpose of this paper is to determine the cyberbullying sensitivity levels of high school students and their perceived social supports levels, and analyze the variables that predict cyberbullying sensitivity. In addition, whether cyberbullying sensitivity levels and social support levels differed according to gender was also…

  2. Analysis of Cyberbullying Sensitivity Levels of High School Students and Their Perceived Social Support Levels

    Science.gov (United States)

    Akturk, Ahmet Oguz

    2015-01-01

    Purpose: The purpose of this paper is to determine the cyberbullying sensitivity levels of high school students and their perceived social supports levels, and analyze the variables that predict cyberbullying sensitivity. In addition, whether cyberbullying sensitivity levels and social support levels differed according to gender was also…

  3. High-Performance X-ray Detection in a New Analytical Electron Microscope

    Science.gov (United States)

    Lyman, C. E.; Goldstein, J. I.; Williams, D. B.; Ackland, D. W.; vonHarrach, S.; Nicholls, A. W.; Statham, P. J.

    1994-01-01

    X-ray detection by energy-dispersive spectrometry in the analytical electron microscope (AEM) is often limited by low collected X-ray intensity (P), modest peak-to-background (P/B) ratios, and limitations on total counting time (tau) due to specimen drift and contamination. A new AFM has been designed with maximization of P. P/B, and tau as the primary considerations. Maximization of P has been accomplished by employing a field-emission electron gun, X-ray detectors with high collection angles, high-speed beam blanking to allow only one photon into the detector at a time, and simultaneous collection from two detectors. P/B has been maximized by reducing extraneous background signals generated at the specimen holder, the polepieces and the detector collimator. The maximum practical tau has been increased by reducing specimen contamination and employing electronic drift correction. Performance improvments have been measured using the NIST standard Cr thin film. The 0-3 steradian solid angle of X-ray collection is the highest value available. The beam blanking scheme for X-ray detection provides 3-4 times greater throughput of X-rays at high count rates into a recorded spectrum than normal systems employing pulse-pileup rejection circuits. Simultaneous X-ray collection from two detectors allows the highest X-ray intensity yet recorded to be collected from the NIST Cr thin film. The measured P/B of 6300 is the highest level recorded for an AEM. In addition to collected X-ray intensity (cps/nA) and P/B measured on the standard Cr film, the product of these can be used as a figure-of-merit to evaluate instruments. Estimated minimum mass fraction (MMF) for Cr measured on the standard NIST Cr thin film is also proposed as a figure-of-merit for comparing X-ray detection in AEMs. Determinations here of the MMF of Cr detectable show at least a threefold improvement over previous instruments.

  4. Sensitivity analysis for high accuracy proximity effect correction

    Science.gov (United States)

    Thrun, Xaver; Browning, Clyde; Choi, Kang-Hoon; Figueiro, Thiago; Hohle, Christoph; Saib, Mohamed; Schiavone, Patrick; Bartha, Johann W.

    2015-10-01

    A sensitivity analysis (SA) algorithm was developed and tested to comprehend the influences of different test pattern sets on the calibration of a point spread function (PSF) model with complementary approaches. Variance-based SA is the method of choice. It allows attributing the variance of the output of a model to the sum of variance of each input of the model and their correlated factors.1 The objective of this development is increasing the accuracy of the resolved PSF model in the complementary technique through the optimization of test pattern sets. Inscale® from Aselta Nanographics is used to prepare the various pattern sets and to check the consequences of development. Fraunhofer IPMS-CNT exposed the prepared data and observed those to visualize the link of sensitivities between the PSF parameters and the test pattern. First, the SA can assess the influence of test pattern sets for the determination of PSF parameters, such as which PSF parameter is affected on the employments of certain pattern. Secondly, throughout the evaluation, the SA enhances the precision of PSF through the optimization of test patterns. Finally, the developed algorithm is able to appraise what ranges of proximity effect correction is crucial on which portion of a real application pattern in the electron beam exposure.

  5. Development of a high sensitive MEMS hydrophone using PVDF

    Science.gov (United States)

    Varadan, Vijay K.; Zhu, Bei; K. A, Jose

    2002-05-01

    The design and experimental evaluation of a PVDF-based MEMS hydrophone is presented in this paper. The basic structure of the hydrophone was fabricated on a silicon wafer using standard NMOS process technology. A MOSFET with extended gate electrode was designed as the interface circuit to the sensing material, which is a piezoelectric polymer, polyvinylidene difluoride (PVDF). Acoustic impedance possessed by this piezoelectric material provides a reasonable match to water, which makes it very attractive for underwater applications. The electrical signal generated by the PVDF film was directly coupled to the gate of the MOSFET. To minimize the parasitic capacitance underneath the PVDF film and hence improve the device sensitivity, a thick photoresist was first employed as the dielectric layer under the extended gate electrode. For underwater operation, a waterproof Rho-C rubber encapsulated the hydrophone. A silicon nitride layer passivated the active device, which is a good barrier material to most mobile ions and solvents. The device after passivation also shows a lower noise level. The theoretical model developed to predict the sensitivity of the hydrophone shows a reasonable agreement between the theory and the experiment.

  6. Photothermal Microscopy for High Sensitivity and High Resolution Absorption Contrast Imaging of Biological Tissues

    Directory of Open Access Journals (Sweden)

    Jun Miyazaki

    2017-04-01

    Full Text Available Photothermal microscopy is useful to visualize the distribution of non-fluorescence chromoproteins in biological specimens. Here, we developed a high sensitivity and high resolution photothermal microscopy with low-cost and compact laser diodes as light sources. A new detection scheme for improving signal to noise ratio more than 4-fold is presented. It is demonstrated that spatial resolution in photothermal microscopy is up to nearly twice as high as that in the conventional widefield microscopy. Furthermore, we demonstrated the ability for distinguishing or identifying biological molecules with simultaneous muti-wavelength imaging. Simultaneous photothermal and fluorescence imaging of mouse brain tissue was conducted to visualize both neurons expressing yellow fluorescent protein and endogenous non-fluorescent chromophores.

  7. High temperature probe sensor with high sensitivity based on Michelson interferometer

    Science.gov (United States)

    Zhao, Na; Fu, Haiwei; Shao, Min; Yan, Xu; Li, Huidong; Liu, Qinpeng; Gao, Hong; Liu, Yinggang; Qiao, Xueguang

    2015-05-01

    A novel Michelson interferometer based on a bi-taper is achieved. Such a device is fabricated by splicing a section of thin core fiber (TCF) at one end of single-mode fiber (SMF). Due to the fiber bi-taper at the splicing point of SMF and TCF, the light is coupled into the fiber core and cladding from lead in fiber core. The light will be reflected at the end of the fiber and then will be recoupled back into the lead out fiber core by the fiber bi-taper. While the light returns back to the lead out fiber, the intermodal interference will occur for the optical path difference between core mode and cladding mode. A high temperature sensitivity of 0.140 nm/°C is achieved from 30 to 800 °C, and the linearity is 99.9%. The configuration features the advantages of easy fabrication, a compact size, high sensitivity, wide sensing range and high mechanical strength, making it a good candidate for distant temperature sensing and oil prospecting.

  8. A new compact, high sensitivity neutron imaging system

    Energy Technology Data Exchange (ETDEWEB)

    Caillaud, T.; Landoas, O.; Briat, M.; Rosse, B.; Thfoin, I.; Philippe, F.; Casner, A.; Bourgade, J. L.; Disdier, L. [CEA, DAM, DIF,F-91297 Arpajon (France); Glebov, V. Yu.; Marshall, F. J.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Park, H. S.; Robey, H. F.; Amendt, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

    2012-10-15

    We have developed a new small neutron imaging system (SNIS) diagnostic for the OMEGA laser facility. The SNIS uses a penumbral coded aperture and has been designed to record images from low yield (10{sup 9}-10{sup 10} neutrons) implosions such as those using deuterium as the fuel. This camera was tested at OMEGA in 2009 on a rugby hohlraum energetics experiment where it recorded an image at a yield of 1.4 Multiplication-Sign 10{sup 10}. The resolution of this image was 54 {mu}m and the camera was located only 4 meters from target chamber centre. We recently improved the instrument by adding a cooled CCD camera. The sensitivity of the new camera has been fully characterized using a linear accelerator and a {sup 60}Co {gamma}-ray source. The calibration showed that the signal-to-noise ratio could be improved by using raw binning detection.

  9. Carbon nanotube quantum dots as highly sensitive THz spectrometers

    Science.gov (United States)

    Rinzan, Mohamed; Jenkins, Greg; Drew, Dennis; Shafranjuk, Serhii; Barbara, Paola

    2012-02-01

    We show that carbon nanotube quantum dots (CNT-Dots) coupled to antennas are extremely sensitive, broad-band, terahertz quantum detectors. Their response is due to photon-assisted single-electron tunneling (PASET)[1], but cannot be fully understood with orthodox PASET models[2]. We consider intra-dot excitations and non-equilibrium cooling to explain the anomalous response. REFERENCES: [1] Y. Kawano, S. Toyokawa, T. Uchida and K. Ishibashi, THz photon assisted tunneling in carbon-nanotube quantum dots, Journal of Applied Physics 103, 034307 (2008). [2] P. K. Tien and J. P. Gordon, Multiphoton Process Observed in the Interaction of Microwave Fields with the Tunneling between Superconductor Films, Phys. Rev. 129, 647 (1963).

  10. High-sensitivity observations of solar flare decimeter radiation

    CERN Document Server

    Benz, Arnold O; Monstein, C; Benz, Arnold O.; Messmer, Peter; Monstein, Christian

    2000-01-01

    A new acousto-optic radio spectrometer has observed the 1 - 2 GHz radio emission of solar flares with unprecedented sensitivity. The number of detected decimeter type III bursts is greatly enhanced compared to observations by conventional spectrometers observing only one frequency at the time. The observations indicate a large number of electron beams propagating in dense plasmas. For the first time, we report weak, reversed drifting type III bursts at frequencies above simultaneous narrowband decimeter spikes. The type III bursts are reliable signatures of electron beams propagating downward in the corona, apparently away from the source of the spikes. The observations contradict the most popular spike model that places the spike sources at the footpoints of loops. Conspicuous also was an apparent bidirectional type U burst forming a fish-like pattern. It occurs simultaneously with an intense U-burst at 600-370 MHz observed in Tremsdorf. We suggest that it intermodulated with strong terrestrial interference ...

  11. Highly sensitive biosensors based on water-soluble conjugated polymers

    Institute of Scientific and Technical Information of China (English)

    XU Hui; WU Haiping; FAN Chunhai; LI Wenxin; ZHANG Zhizhou; HE Lin

    2004-01-01

    Conjugated, conductive polymers are a kind of important organic macromolecules, which has found applications in a variety of areas. The application of conjugated polymers in developing fluorescent biosensors represents the merge of polymer sciences and biological sciences. Conjugated polymers are very good light harvesters as well as fluorescent polymers, and they are also "molecular wires". Through elaborate designs, these important features, i.e. efficient light harvesting and electron/energy transfer, can be used as signal amplification in fluorescent biosensors. This might significantly improve the sensitivity of conjugated polymer-based biosensors. In this article, we reviewed the application of conjugated polymers, via either electron transfer or energy transfer, to detections of gene targets, antibodies or enzymes. We also reviewed recent efforts in conjugated polymer-based solid-state sensor designs as well as chip-based multiple target detection. Possible directions in this conjugated polymer-based biosensor area are also discussed.

  12. Highly sensitive urea sensing with ion-irradiated polymer foils

    Energy Technology Data Exchange (ETDEWEB)

    Fink, Dietmar, E-mail: fink@daad-alumni.de [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 Mexico, D.F. (Mexico); Nuclear Physics Institute, Academy of Sciences of the Czech Republic, 250 68 Rez (Czech Republic); Munoz Hernandez, Gerardo [Departamento de Fisica, Universidad Autonoma Metropolitana-Iztapalapa, P.O. Box 55-534, 09340 Mexico, D.F. (Mexico); Division de Ciencias Naturales e Ingenieria, Universidad Autonoma Metropolitana-Cuajimalpa, Pedro Antonio de los Santos 84, Col. Sn. Miguel Chapultepec, C.P. 11850, Mexico, D.F. (Mexico); Alfonta, Lital, E-mail: alfontal@bgu.ac.il [Avram and Stella Goldstein-Goren Department of Biotechnology Engineering, Ben-Gurion University of the Negev, P.O. Box 653, Beer-Sheva 84105 (Israel)

    2012-02-15

    Recently we prepared urea-sensors by attaching urease to the inner walls of etched ion tracks within thin polymer foil. Here, alternative track-based sensor configurations are examined where the enzyme remained in solution. The conductivities of systems consisting of two parallel irradiated polymer foils and confining different urea/urease mixtures in between were examined. The correlations between conductivity and urea concentration differed strongly for foils with unetched and etched tracks, which points at different sensing mechanisms - tentatively attributed to the adsorption of enzymatic reaction products on the latent track entrances and to the enhanced conductivity of reaction product-filled etched tracks, respectively. All examined systems enable in principle, urea sensing. They point at the possibility of sensor cascade construction for more sensitive or selective sensor systems.

  13. Quantitative determination of several toxicological important mycotoxins in pig plasma using multi-mycotoxin and analyte-specific high performance liquid chromatography-tandem mass spectrometric methods.

    Science.gov (United States)

    Devreese, Mathias; De Baere, Siegrid; De Backer, Patrick; Croubels, Siska

    2012-09-28

    A sensitive and reliable multi-mycotoxin method was developed for the identification and quantification of several toxicological important mycotoxins such as deoxynivalenol (DON), deepoxy-deoxynivalenol (DOM-1), T-2 toxin (T-2), HT-2 toxin (HT-2), zearalenone (ZON), zearalanone (ZAN), α-zearalenol (α-ZOL), β-zearalenol (β-ZOL), α-zearalanol (α-ZAL), β-zearalanol (β-ZAL), ochratoxin A (OTA), fumonisin B1 (FB1) and aflatoxin B1 (AFB1) in pig plasma using liquid chromatography combined with heated electrospray ionization triple quadrupole tandem mass spectrometry (LC-h-ESI-MS/MS). Sample clean-up consisted of a deproteinization step using acetonitrile, followed by evaporation of the supernatant and resuspension of the dry residue in water/methanol (85/15, v/v). Each plasma sample was analyzed twice, i.e. once in the ESI+ and ESI- mode, respectively. This method can be used for the assessment of animal exposure to mycotoxins and in the diagnosis of mycotoxicoses. For the performance of toxicokinetic studies with individual mycotoxins, highly sensitive analyte-specific LC-MS/MS methods were developed. The multi-mycotoxin and analyte-specific methods were in-house validated: matrix-matched calibration graphs were prepared for all compounds and correlation and goodness-of-fit coefficients ranged between 0.9974-0.9999 and 2.4-15.5%, respectively. The within- and between-run precision and accuracy were evaluated and the results fell within the ranges specified. The limits of quantification for the multi-mycotoxin and analyte-specific methods ranged from 2 to 10 ng/mL and 0.5 to 5 ng/mL, respectively, whereas limits of detection fell between 0.01-0.52 ng/mL and <0.01-0.15 ng/mL, respectively.

  14. Analytical calculations of anode plasma position in high-voltage discharge range in case of auxiliary discharge firing

    OpenAIRE

    Melnyk, Igor V.; Tugay, S. B.

    2012-01-01

    We consider the mathematical model of triode high-voltage glow discharge range in case of auxiliary discharge firing. On a basis of analysis of elementary processes of charged particles interaction in a discharge range we obtain analytical relation, which allows to obtain the anode plasma position with regard to the cathode. Obtained results can be used for analysis of analysis of energy balance in a discharge range and self-maintained electron-ion optics of high voltage glow discharge electr...

  15. Thermoelastic analysis of spent fuel and high level radioactive waste repositories in salt. A semi-analytical solution. [JUDITH

    Energy Technology Data Exchange (ETDEWEB)

    St. John, C.M.

    1977-04-01

    An underground repository containing heat generating, High Level Waste or Spent Unreprocessed Fuel may be approximated as a finite number of heat sources distributed across the plane of the repository. The resulting temperature, displacement and stress changes may be calculated using analytical solutions, providing linear thermoelasticity is assumed. This report documents a computer program based on this approach and gives results that form the basis for a comparison between the effects of disposing of High Level Waste and Spent Unreprocessed Fuel.

  16. High-sensitivity in situ QCLAS-based ammonia concentration sensor for high-temperature applications

    Science.gov (United States)

    Peng, W. Y.; Sur, R.; Strand, C. L.; Spearrin, R. M.; Jeffries, J. B.; Hanson, R. K.

    2016-07-01

    A novel quantum cascade laser (QCL) absorption sensor is presented for high-sensitivity in situ measurements of ammonia (hbox {NH}_3) in high-temperature environments, using scanned wavelength modulation spectroscopy (WMS) with first-harmonic-normalized second-harmonic detection (scanned WMS-2 f/1 f) to neutralize the effect of non-absorption losses in the harsh environment. The sensor utilized the sQ(9,9) transition of the fundamental symmetric stretch band of hbox {NH}_3 at 10.39 {\\upmu }hbox {m} and was sinusoidally modulated at 10 kHz and scanned across the peak of the absorption feature at 50 Hz, leading to a detection bandwidth of 100 Hz. A novel technique was used to select an optimal WMS modulation depth parameter that reduced the sensor's sensitivity to spectral interference from hbox {H}_2hbox {O} and hbox {CO}_2 without significantly sacrificing signal-to-noise ratio. The sensor performance was validated by measuring known concentrations of hbox {NH}_3 in a flowing gas cell. The sensor was then demonstrated in a laboratory-scale methane-air burner seeded with hbox {NH}_3, achieving a demonstrated detection limit of 2.8 ± 0.26 ppm hbox {NH}_3 by mole at a path length of 179 cm, equivalence ratio of 0.6, pressure of 1 atm, and temperatures of up to 600 K.

  17. Highly sensitive glucose biosensor based on Au-Ni coaxial nanorod array having high aspect ratio.

    Science.gov (United States)

    Hsu, Che-Wei; Wang, Gou-Jen

    2014-06-15

    An effective glucose biosensor requires a sufficient amount of GOx immobilizing on the electrode surface. An electrode of a 3D nanorod array, having a larger surface-to-volume ratio than a 2D nanostructure, can accommodate more GOx molecules to immobilize onto the surface of the nanorods. In this study, a highly sensitive Au-Ni coaxial nanorod array electrode fabricated through the integration of nano electroforming and immersion gold (IG) method for glucose detection was developed. The average diameter of the as-synthesized Ni nanorods and that of the Au-Ni nanorods were estimated to be 150 and 250 nm, respectively; both had a height of 30 μm. The aspect ratio was 120. Compared to that of a flat Au electrode, the effective sensing area was enhanced by 79.8 folds. Actual glucose detections demonstrated that the proposed Au-Ni coaxial nanorod array electrode could operate in a linear range of 27.5 μM-27.5mM with a detection limit of 5.5μM and a very high sensitivity of 769.6 μA mM(-1)cm(-2). Good selectivity of the proposed sensing device was verified by sequential injections of uric acid (UA) and ascorbic acid (AA). Long-term stability was examined through successive detections over a period of 30 days.

  18. Nitrogen detected TROSY at high field yields high resolution and sensitivity for protein NMR

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Koh [National Institute for Advanced Industrial Science and Technology, Molecular Profiling Research Center for Drug Discovery (Japan); Arthanari, Haribabu [Harvard Medical School, Department of Biochemistry and Molecular Pharmacology (United States); Shimada, Ichio, E-mail: shimada@iw-nmr.f.u-tokyo.ac.jp [National Institute for Advanced Industrial Science and Technology, Molecular Profiling Research Center for Drug Discovery (Japan); Wagner, Gerhard, E-mail: gerhard-wagner@hms.harvard.edu [Harvard Medical School, Department of Biochemistry and Molecular Pharmacology (United States)

    2015-12-15

    Detection of {sup 15}N in multidimensional NMR experiments of proteins has sparsely been utilized because of the low gyromagnetic ratio (γ) of nitrogen and the presumed low sensitivity of such experiments. Here we show that selecting the TROSY components of proton-attached {sup 15}N nuclei (TROSY {sup 15}N{sub H}) yields high quality spectra in high field magnets (>600 MHz) by taking advantage of the slow {sup 15}N transverse relaxation and compensating for the inherently low {sup 15}N sensitivity. The {sup 15}N TROSY transverse relaxation rates increase modestly with molecular weight but the TROSY gain in peak heights depends strongly on the magnetic field strength. Theoretical simulations predict that the narrowest line width for the TROSY {sup 15}N{sub H} component can be obtained at 900 MHz, but sensitivity reaches its maximum around 1.2 GHz. Based on these considerations, a {sup 15}N-detected 2D {sup 1}H–{sup 15}N TROSY-HSQC ({sup 15}N-detected TROSY-HSQC) experiment was developed and high-quality 2D spectra were recorded at 800 MHz in 2 h for 1 mM maltose-binding protein at 278 K (τ{sub c} ∼ 40 ns). Unlike for {sup 1}H detected TROSY, deuteration is not mandatory to benefit {sup 15}N detected TROSY due to reduced dipolar broadening, which facilitates studies of proteins that cannot be deuterated, especially in cases where production requires eukaryotic expression systems. The option of recording {sup 15}N TROSY of proteins expressed in H{sub 2}O media also alleviates the problem of incomplete amide proton back exchange, which often hampers the detection of amide groups in the core of large molecular weight proteins that are expressed in D{sub 2}O culture media and cannot be refolded for amide back exchange. These results illustrate the potential of {sup 15}N{sub H}-detected TROSY experiments as a means to exploit the high resolution offered by high field magnets near and above 1 GHz.

  19. High Sensitivity Optomechanical Reference Accelerometer over 10 kHz

    Science.gov (United States)

    2014-06-05

    characterizing fast mechanical dynamics and piezo -electric devices, but typically not both. Yet extremely high resolution maintained over large...applying a ringdown technique in vacuum. To this end, we used a piezo -shaker to excite the oscillator at its resonance frequency and measured the...exponential decay response. The resonance peak was determined by spectral analysis and then honed in by a high resolution function generator driving the piezo

  20. Achieving tunable sensitivity in composite high-energy density materials

    Science.gov (United States)

    Kuklja, Maija M.; Tsyshevsky, Roman V.; Rashkeev, Sergey

    2017-01-01

    Laser irradiation provides a unique opportunity for selective, predictive, and controlled initiation of energetic materials. We propose a consistent micro-scale mechanism of photoexcitation at the interface, formed by a molecular energetic material and a metal oxide. A specific PETN-MgO model composite is used to illustrate and explain seemingly puzzling experiments on selective laser initiation of energetic materials, which reported that the presence of metal oxide additives triggered the photoinitiation by an unusually low energy. We suggest that PETN photodecomposition is catalyzed by oxygen vacancies (F0 centers) at the MgO surface. The proposed model suggests ways to tune sensitivity of energetic molecular materials to photoinitiation. Our quantum-chemical calculations suggest that the structural point defects (e.g., oxygen vacancies) strongly interact with the molecular material (e.g., adsorbed energetic molecules) by inducing a charge transfer at the interface and hence play an imperative role in governing both energy absorption and energy release in the system. Our approach and conclusions provide a solid basis for novel design of energetic interfaces with desired properties and offers a new perspective in the field of explosive materials and devices.

  1. High-sensitivity observations of solar flare decimeter radiation

    Science.gov (United States)

    Benz, A. O.; Messmer, P.; Monstein, C.

    2001-01-01

    A new acousto-optic radio spectrometer has observed the 1-2 GHz radio emission of solar flares with unprecedented sensitivity. The number of detected decimeter type III bursts is greatly enhanced compared to observations by conventional spectrometers observing only one frequency at the time. The observations indicate a large number of electron beams propagating in dense plasmas. For the first time, we report weak, reversed drifting type III bursts at frequencies above simultaneous narrowband decimeter spikes. The type III bursts are reliable signatures of electron beams propagating downward in the corona, apparently away from the source of the spikes. The observations contradict the most popular spike model that places the spike sources at the footpoints of loops. Conspicuous also was an apparent bidirectional type U burst forming a fish-like pattern. It occurs simultaneously with an intense U-burst at 600-370 MHz observed in Tremsdorf. We suggest that it intermodulated with strong terrestrial interference(cellular phones) causing a spurious symmetric pattern in the spectrogram at 1.4 GHz. Symmetric features in the 1-2 GHz range, some already reported in the literature, therefore must be considered with utmost caution.

  2. A low-cost smartphone-based platform for highly sensitive point-of-care testing with persistent luminescent phosphors.

    Science.gov (United States)

    Paterson, Andrew S; Raja, Balakrishnan; Mandadi, Vinay; Townsend, Blane; Lee, Miles; Buell, Alex; Vu, Binh; Brgoch, Jakoah; Willson, Richard C

    2017-03-14

    Through their computational power and connectivity, smartphones are poised to rapidly expand telemedicine and transform healthcare by enabling better personal health monitoring and rapid diagnostics. Recently, a variety of platforms have been developed to enable smartphone-based point-of-care testing using imaging-based readout with the smartphone camera as the detector. Fluorescent reporters have been shown to improve the sensitivity of assays over colorimetric labels, but fluorescence readout necessitates incorporating optical hardware into the detection system, adding to the cost and complexity of the device. Here we present a simple, low-cost smartphone-based detection platform for highly sensitive luminescence imaging readout of point-of-care tests run with persistent luminescent phosphors as reporters. The extremely bright and long-lived emission of persistent phosphors allows sensitive analyte detection with a smartphone by a facile time-gated imaging strategy. Phosphors are first briefly excited with the phone's camera flash, followed by switching off the flash, and subsequent imaging of phosphor luminescence with the camera. Using this approach, we demonstrate detection of human chorionic gonadotropin using a lateral flow assay and the smartphone platform with strontium aluminate nanoparticles as reporters, giving a detection limit of ≈45 pg mL(-1) (1.2 pM) in buffer. Time-gated imaging on a smartphone can be readily adapted for sensitive and potentially quantitative testing using other point-of-care formats, and is workable with a variety of persistent luminescent materials.

  3. Highly Sensitive GMO Detection Using Real-Time PCR with a Large Amount of DNA Template: Single-Laboratory Validation.

    Science.gov (United States)

    Mano, Junichi; Hatano, Shuko; Nagatomi, Yasuaki; Futo, Satoshi; Takabatake, Reona; Kitta, Kazumi

    2017-08-28

    Current genetically modified organism (GMO) detection methods allow for sensitive detection. However, a further increase in sensitivity will enable more efficient testing for large grain samples and reliable testing for processed foods. In this study, we investigated real-time PCR-based GMO detection methods using a large amount of DNA template. We selected target sequences that are commonly introduced into many kinds of GM crops, i.e., 35S promoter and nopaline synthase (NOS) terminator. This makes the newly developed method applicable to a wide range of GMOs, including some unauthorized ones. The estimated LOD of the new method was 0.005% of GM maize events; to the best of our knowledge, this method is the most sensitive among the GM maize detection methods for which the LOD was evaluated in terms of GMO content. A 10-fold increase in the DNA amount as compared with the amount used under common testing conditions gave an approximately 10-fold reduction in the LOD without PCR inhibition. Our method is applicable to various analytical samples, including processed foods. The use of other primers and fluorescence probes would permit highly sensitive detection of various recombinant DNA sequences besides the 35S promoter and NOS terminator.

  4. Direct quantification of lycopene in products derived from thermally processed tomatoes: optothermal window as a selective, sensitive, and accurate analytical method without the need for preparatory steps.

    Science.gov (United States)

    Bicanic, Dane; Swarts, Jan; Luterotti, Svjetlana; Pietraperzia, Giangaetano; Dóka, Otto; de Rooij, Hans

    2004-09-01

    The concept of the optothermal window (OW) is proposed as a reliable analytical tool to rapidly determine the concentration of lycopene in a large variety of commercial tomato products in an extremely simple way (the determination is achieved without the need for pretreatment of the sample). The OW is a relative technique as the information is deduced from the calibration curve that relates the OW data (i.e., the product of the absorption coefficient beta and the thermal diffusion length micro) with the lycopene concentration obtained from spectrophotometric measurements. The accuracy of the method has been ascertained with a high correlation coefficient (R = 0.98) between the OW data and results acquired from the same samples by means of the conventional extraction spectrophotometric method. The intrinsic precision of the OW method is quite high (better than 1%), whereas the repeatability of the determination (RSD = 0.4-9.5%, n= 3-10) is comparable to that of spectrophotometry.

  5. Chromatic analysis by monitoring unmodified silver nanoparticles reduction on double layer microfluidic paper-based analytical devices for selective and sensitive determination of mercury(II).

    Science.gov (United States)

    Meelapsom, Rattapol; Jarujamrus, Purim; Amatatongchai, Maliwan; Chairam, Sanoe; Kulsing, Chadin; Shen, Wei

    2016-08-01

    This study demonstrates chromatic analysis based on a simple red green blue (RGB) color model for sensitive and selective determination of mercury(II). The analysis was performed by monitoring the color change of a microfluidic Paper-based Analytical Device (µPAD). The device was fabricated by using alkyl ketene dimer (AKD)-inkjet printing and doped with unmodified silver nanoparticles (AgNPs) which were disintegrated when being exposed to mercury(II). The color intensity was detected by using an apparatus consisting of a digital camera and a homemade light box generating constant light intensity. A progressive increase in color intensity of the tested area on the µPAD (3.0mm) was observed with increasing mercury(II) concentration. The developed system enabled quantification of mercury(II) at low concentration with the detection limit of 0.001mgL(-1) (3 SD blank/slope of the calibration curve) and small sample volume uptake (2µL). The linearity range of the calibration curve in this technique was demonstrated from 0.05 to 7mgL(-1) (r(2)=0.998) with good precision (RSD less than 4.1%). Greater selectivity towards mercury(II) compared with potential interference ions was also observed. Furthermore, the percentage recoveries of spiked water samples were in an acceptable range which was in agreement with the values obtained from the conventional method utilizing cold vapor atomic absorption spectrometer (CVAAS). The proposed technique allows a rapid, simple, sensitive and selective analysis of trace mercury(II) in water samples.

  6. High sensitivity of Giardia duodenalis to tetrahydrolipstatin (orlistat in vitro.

    Directory of Open Access Journals (Sweden)

    Juliane Hahn

    Full Text Available Giardiasis, a gastrointestinal disease caused by Giardia duodenalis, is currently treated mainly with nitroimidazoles, primarily metronidazole (MTZ. Treatment failure rates of up to 20 percent reflect the compelling need for alternative treatment options. Here, we investigated whether orlistat, a drug approved to treat obesity, represents a potential therapeutic agent against giardiasis. We compared the growth inhibitory effects of orlistat and MTZ on a long-term in vitro culture adapted G. duodenalis strain, WB-C6, and on a new isolate, 14-03/F7, from a patient refractory to MTZ treatment using a resazurin assay. The giardiacidal concentration of the drugs and their combined in vitro efficacy was determined by median-effect analysis. Morphological changes after treatment were analysed by light and electron microscopy. Orlistat inhibited the in vitro growth of G. duodenalis at low micromolar concentrations, with isolate 14-03/F7 (IC50(24h = 2.8 µM being more sensitive than WB-C6 (IC50(24h = 6.2 µM. The effect was significantly more potent compared to MTZ (IC50(24h = 4.3 µM and 11.0 µM, respectively and led to specific undulated morphological alterations on the parasite surface. The giardiacidal concentration of orlistat was >14 µM for 14-03/F7 and >43 µM for WB-C6, respectively. Importantly, the combination of both drugs revealed no interaction on their inhibitory effects. We demonstrate that orlistat is a potent inhibitor of G. duodenalis growth in vitro and kills parasites at concentrations achievable in the gut by approved treatment regimens for obesity. We therefore propose to investigate orlistat in controlled clinical studies as a new drug in giardiasis.

  7. High sensitivity of Giardia duodenalis to tetrahydrolipstatin (orlistat) in vitro.

    Science.gov (United States)

    Hahn, Juliane; Seeber, Frank; Kolodziej, Herbert; Ignatius, Ralf; Laue, Michael; Aebischer, Toni; Klotz, Christian

    2013-01-01

    Giardiasis, a gastrointestinal disease caused by Giardia duodenalis, is currently treated mainly with nitroimidazoles, primarily metronidazole (MTZ). Treatment failure rates of up to 20 percent reflect the compelling need for alternative treatment options. Here, we investigated whether orlistat, a drug approved to treat obesity, represents a potential therapeutic agent against giardiasis. We compared the growth inhibitory effects of orlistat and MTZ on a long-term in vitro culture adapted G. duodenalis strain, WB-C6, and on a new isolate, 14-03/F7, from a patient refractory to MTZ treatment using a resazurin assay. The giardiacidal concentration of the drugs and their combined in vitro efficacy was determined by median-effect analysis. Morphological changes after treatment were analysed by light and electron microscopy. Orlistat inhibited the in vitro growth of G. duodenalis at low micromolar concentrations, with isolate 14-03/F7 (IC50(24h) = 2.8 µM) being more sensitive than WB-C6 (IC50(24h) = 6.2 µM). The effect was significantly more potent compared to MTZ (IC50(24h) = 4.3 µM and 11.0 µM, respectively) and led to specific undulated morphological alterations on the parasite surface. The giardiacidal concentration of orlistat was >14 µM for 14-03/F7 and >43 µM for WB-C6, respectively. Importantly, the combination of both drugs revealed no interaction on their inhibitory effects. We demonstrate that orlistat is a potent inhibitor of G. duodenalis growth in vitro and kills parasites at concentrations achievable in the gut by approved treatment regimens for obesity. We therefore propose to investigate orlistat in controlled clinical studies as a new drug in giardiasis.

  8. HIGH SENSITIVE C-REACTIVE PROTEIN IN CEREBROVASCULAR ISCHEMIA

    Directory of Open Access Journals (Sweden)

    Padmalatha

    2016-02-01

    Full Text Available BACKGROUND Cerebrovascular ischemia is recognized as a major health problem, which causes significant morbidity and mortality. The main pathophysiology of ischemic stroke is atherosclerosis of cerebral vessels. Hs-CRP is a sensitive marker of inflammation tissue injury in the arterial wall, which contributes to atherosclerosis. In this study, we aim to investigate the association of hs-CRP in patients with ischemic stroke and to correlate hs-CRP levels with possible risk factors of ischemic stroke and to assess the prognostic value of hs-CRP in ischemic stroke. METHODS In the present case control study after meeting inclusion and exclusion criteria, 50 patients with acute ischemic stroke admitted in the medical ward, King George Hospital, during the period between April 2014 and October 2014 and 40 asymptomatic age and sex matched control subjects were included. RESULTS The mean hs-CRP value in cases is 3.78+5.28mg/dl and in controls is 0.425+0.305mg/dl. Mean hs-CRP value is higher (3.78mg/dl in cases when compared to controls (0.425mg/dl, which is statistically significant. P admitted with severe degree of weakness (0-1/5 power with mean hs-CRP value of 4.28+4.07 without significant improvement in the power at the time of discharge; 8(16%> with mean hs-CRP value of 10.43+7.74 were expired. CONCLUSION Acute ischemic patients had higher mean hs-CRP values when compared to healthy asymptomatic control subjects P0.05. Higher mean hs-CRP values were associated with poor outcome after acute ischemic stroke. P<0.001.

  9. High Sensitivity Indium Phosphide Based Avalanche Photodiode Focal Plane Arrays Project

    Data.gov (United States)

    National Aeronautics and Space Administration — nLight has demonstrated highly-uniform APD arrays based on the highly sensitive InGaAs/InP material system. These results provide great promise for achieving the...

  10. Polycarbonates: a long-term highly sensitive radon monitor

    CERN Document Server

    Pressyanov, D; Poffijn, A; Meesen, G; Deynse, A V

    2000-01-01

    An approach for long-term (either retrospective or prospective) sup 2 sup 2 sup 2 Rn measurements is proposed that is based on the combination of the high radon absorption ability of some polycarbonates with their alpha track-etch properties. The detection limit is projected to be <10 Bq m sup - sup 3 for an exposure time of 20 yr.

  11. Pyrrolizidine alkaloids in honey: comparison of analytical methods

    NARCIS (Netherlands)

    Kempf, M.; Wittig, M.; Reinhard, A.; Ohe, von der K.; Blacquière, T.; Raezke, K.P.; Michel, R.; Schreier, P.; Beuerle, T.

    2011-01-01

    Pyrrolizidine alkaloids (PAs) are a structurally diverse group of toxicologically relevant secondary plant metabolites. Currently, two analytical methods are used to determine PA content in honey. To achieve reasonably high sensitivity and selectivity, mass spectrometry detection is demanded. One me

  12. Sensitive Detection of Melamine in Infant Milk and Coffee Mate by a Buffer Mediated Extraction and HPLC-PDA Analytical Method

    Directory of Open Access Journals (Sweden)

    Maryam Rezai

    2014-12-01

    Full Text Available Melamine is a potentially hazardous compound and one of the major concerns especially in dairy products and pet foods. In the present study a sensitive, simple and reliable method for extraction and determination of melamine in infant milk and coffee mate has been developed. This method consists of an initial extraction in buffer media prepared by formic acid and sodium formate, followed by protein precipitation by acetonitrile and dichloromethane. The chromatographic separation was carried out on a 100-Nucleosil -NH2 column with an optimized acetonitrile-water (80:20 v/v as a mobile phase and with a photodiode-array detector. The analytical method was validated according to the validation parameters, such as, selectivity, linearity (0.08-10 µg/mL, with r2= 0.9998 and 0.05-10 µg/mL with r2= 0.9997, precision (intra-day 0.52-2.66%, 0.78-1.20; inter-day 2.96-4.20%, 2.80-3.00% and accuracy (92-102%, 92-100% for powdered milk and coffee mates respectively. The limits of detection and quantization were 0.02, 0.08 µg/mL for powdered milk and 0.01, 0.05 µg/mL for coffee mate, respectively.

  13. Mass Spectrometry-based Assay for High Throughput and High Sensitivity Biomarker Verification

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Xuejiang; Tang, Keqi

    2017-06-14

    Searching for disease specific biomarkers has become a major undertaking in the biomedical research field as the effective diagnosis, prognosis and treatment of many complex human diseases are largely determined by the availability and the quality of the biomarkers. A successful biomarker as an indicator to a specific biological or pathological process is usually selected from a large group of candidates by a strict verification and validation process. To be clinically useful, the validated biomarkers must be detectable and quantifiable by the selected testing techniques in their related tissues or body fluids. Due to its easy accessibility, protein biomarkers would ideally be identified in blood plasma or serum. However, most disease related protein biomarkers in blood exist at very low concentrations (<1ng/mL) and are “masked” by many none significant species at orders of magnitude higher concentrations. The extreme requirements of measurement sensitivity, dynamic range and specificity make the method development extremely challenging. The current clinical protein biomarker measurement primarily relies on antibody based immunoassays, such as ELISA. Although the technique is sensitive and highly specific, the development of high quality protein antibody is both expensive and time consuming. The limited capability of assay multiplexing also makes the measurement an extremely low throughput one rendering it impractical when hundreds to thousands potential biomarkers need to be quantitatively measured across multiple samples. Mass spectrometry (MS)-based assays have recently shown to be a viable alternative for high throughput and quantitative candidate protein biomarker verification. Among them, the triple quadrupole MS based assay is the most promising one. When it is coupled with liquid chromatography (LC) separation and electrospray ionization (ESI) source, a triple quadrupole mass spectrometer operating in a special selected reaction monitoring (SRM) mode

  14. Why High Performance Visual Data Analytics is both Relevant and Difficult

    Energy Technology Data Exchange (ETDEWEB)

    Bethel, E. Wes; Byna, Suren; Ruebel, Oliver; Wu, K. John; Wehner, Michael

    2012-12-01

    Data visualization, as well as data analysis and data analytics, are all an integral part of the scientific process. Collectively, these technologies provide the means to gain insight into data of ever-increasing size and complexity. Over the past two decades, a substantial amount of visualization, analysis, and analytics R&D has focused on the challenges posed by increasing data size and complexity, as well as on the increasing complexity of a rapidly changing computational platform landscape. While some of this research focuses on solely on technologies, such as indexing and searching or novel analysis or visualization algorithms, other R&D projects focus on applying technological advances to specific application problems. Some of the most interesting and productive results occur when these two activities R&D and application are conducted in a collaborative fashion, where application needs drive R&D, and R&D results are immediately applicable to real world problems.

  15. A high fidelity Rydberg blockade entangling gate using shaped, analytic pulses

    CERN Document Server

    Theis, L S; Wilhelm, F K; Saffmann, M

    2016-01-01

    We show that the use of shaped pulses improves the fidelity of a Rydberg blockade two-qubit entangling gate by several orders of magnitude compared to previous protocols based on square pulses or optimal control pulses. Using analytical Derivative Removal by Adiabatic Gate (DRAG) pulses that reduce excitation of primary leakage states and an analytical method of finding the optimal Rydberg blockade we generate Bell states with a fidelity of $F>0.9999$ in a 300 K environment for a gate time of only $50\\;{\\rm ns}$, which is an order of magnitude faster than previous protocols. These results establish the potential of neutral atom qubits with Rydberg blockade gates for scalable quantum computation.

  16. Analytical strategy for the determination of various arsenic species in landfill leachate containing high concentrations of chlorine and organic carbon by HPLC-ICPMS

    Science.gov (United States)

    Bae, J.; An, J.; Kim, J.; Jung, H.; Kim, K.; Yoon, C.; Yoon, H.

    2012-12-01

    As a variety of wastes containing arsenic are disposed of in landfills, such facilities can play a prominent role in disseminating arsenic sources to the environment. Since it is widely recognized that arsenic toxicity is highly dependent on its species, accurate determination of various arsenic species should be considered as one of the essential goals to properly account for the potential health risk of arsenic in human and the environment. The inductively coupled plasma mass spectrometry linked to high performance liquid chromatography (HPLC-ICPMS) is acknowledged as one of the most important tools for the trace analysis of metallic speciation because of its superior separation capability and detectability. However, the complexity of matrices can cause severe interferences in the analysis results, which is the problem often encountered with HPLC-ICPMS system. High concentration of organic carbon in a sample solution causes carbon build-up on the skimmer and sampling cone, which reduces analytical sensitivity and requires a high maintenance level for its cleaning. In addition, argon from the plasma and chlorine from the sample matrix may combine to form 40Ar35Cl, which has the same nominal mass to charge (m/z) ratio as arsenic. In this respect, analytical strategy for the determination of various arsenic species (e.g., inorganic arsenite and arsenate, monomethylarsonic acid, dimethylarsinic acid, dimethyldithioarsinic acid, and arsenobetaine) in landfill leachate containing high concentrations of chlorine and organic carbon was developed in the present study. Solid phase extraction disk (i.e., C18 disk), which does not significantly adsorb any target arsenic species, was used to remove organic carbon in sample solutions. In addition, helium (He) gas was injected into the collision reaction cell equipped in ICPMS to collapse 40Ar35Cl into individual 40Ar and 35Cl. Although He gas also decreased arsenic intensity by blocking 75As, its signal to noise ratio

  17. A data model and database for high-resolution pathology analytical image informatics

    Directory of Open Access Journals (Sweden)

    Fusheng Wang

    2011-01-01

    Full Text Available Background: The systematic analysis of imaged pathology specimens often results in a vast amount of morphological information at both the cellular and sub-cellular scales. While microscopy scanners and computerized analysis are capable of capturing and analyzing data rapidly, microscopy image data remain underutilized in research and clinical settings. One major obstacle which tends to reduce wider adoption of these new technologies throughout the clinical and scientific communities is the challenge of managing, querying, and integrating the vast amounts of data resulting from the analysis of large digital pathology datasets. This paper presents a data model, which addresses these challenges, and demonstrates its implementation in a relational database system. Context: This paper describes a data model, referred to as Pathology Analytic Imaging Standards (PAIS, and a database implementation, which are designed to support the data management and query requirements of detailed characterization of micro-anatomic morphology through many interrelated analysis pipelines on whole-slide images and tissue microarrays (TMAs. Aims: (1 Development of a data model capable of efficiently representing and storing virtual slide related image, annotation, markup, and feature information. (2 Development of a database, based on the data model, capable of supporting queries for data retrieval based on analysis and image metadata, queries for comparison of results from different analyses, and spatial queries on segmented regions, features, and classified objects. Settings and Design: The work described in this paper is motivated by the challenges associated with characterization of micro-scale features for comparative and correlative analyses involving whole-slides tissue images and TMAs. Technologies for digitizing tissues have advanced significantly in the past decade. Slide scanners are capable of producing high-magnification, high-resolution images from whole

  18. Highly sensitive SERS-based immunoassay of aflatoxin B1 using silica-encapsulated hollow gold nanoparticles.

    Science.gov (United States)

    Ko, Juhui; Lee, Chankil; Choo, Jaebum

    2015-03-21

    Aflatoxin B1 (AFB1) is a well-known carcinogenic contaminant in foods. It is classified as an extremely hazardous compound because of its potential toxicity to the human nervous system. AFB1 has also been extensively used as a biochemical marker to evaluate the degree of food spoilage. In this study, a novel surface-enhanced Raman scattering (SERS)-based immunoassay platform using silica-encapsulated hollow gold nanoparticles (SEHGNs) and magnetic beads was developed for highly sensitive detection of AFB1. SEHGNs were used as highly stable SERS-encoding nano tags, and magnetic beads were used as supporting substrates for the high-density loading of immunocomplexes. Quantitative analysis of AFB1 was performed by monitoring the intensity change of the characteristic peaks of Raman reporter molecules. The limit of detection (LOD) of AFB1, determined by this SERS-based immunoassay, was determined to be 0.1 ng/mL. This method has some advantages over other analytical methods with respect to rapid analysis (less than 30 min), good selectivity, and reproducibility. The proposed method is expected to be a new analytical tool for the trace analysis of various mycotoxins.

  19. Microstructure-Sensitive Modeling of High Cycle Fatigue (Preprint)

    Science.gov (United States)

    2009-03-01

    history ( carburization and shot peening) and resulting residual stresses are considered in the case of subsurface crack formation at primary inclusions...experimental responses for known microstructures. Effects of process history ( carburization and shot peening) and resulting residual stresses are considered...nonmetallic inclusions. 3. HCF Crack Formation in Carburized and Shot Peened Martensitic Gear Steel High strength low carbon martensitic gear steel is a

  20. A highly selective and sensitive fluorescent chemosensor for Zn2+

    Institute of Scientific and Technical Information of China (English)

    Xiu Ying Zhang; Zuo Hui Wang; Lin Yang

    2008-01-01

    A new selective Zn2+ fluorescent chemosensor,o-vanillin-4-ethoxybenzoylhydrazone(1),was designed and prepared.Free 1 mainly displayed very weak fluorescence at 480 nm upone xcitation at 403 nln.It displayed high selectivity for Zn2+ and had a 518-fold fluorescent enhancement upon binding of Zn2+.while the other cation ions had only little influence on the fluorescence of 1.Mechanism of enhancement of 1's fluorescence by Zn2+ was briefly discussed.

  1. Highly sensitive bolometers for rare alpha decay studies

    Directory of Open Access Journals (Sweden)

    Gironi L.

    2014-03-01

    Full Text Available High resolution detectors able to identify background events are very appealing in the study of rare nuclear processes. Scintillating bolometers featuring simultaneous read-out of heat and scintillation signals, can effectively address this problem thanks to the possibility to discriminate different ionizing particles and achieve background free experiments. With this technique it has already been possible to measure rare alpha decays never observed before or improve by orders of magnitude the existing limits.

  2. Liquid-phase exfoliated graphene as highly-sensitive sensor for simultaneous determination of endocrine disruptors: diethylstilbestrol and estradiol.

    Science.gov (United States)

    Hu, Lintong; Cheng, Qin; Chen, Danchao; Ma, Ming; Wu, Kangbing

    2015-01-01

    It is quite important to develop convenient and rapid analytical methods for trace levels of endocrine disruptors because they heavily affect health and reproduction of humans and animals. Herein, graphene was easily prepared via one-step exfoliation using N-methyl-2-pyrrolidone as solvent, and then used to construct an electrochemical sensor for highly-sensitive detection of diethylstilbestrol (DES) and estradiol (E2). On the surface of prepared graphene film, two independent and greatly-increased oxidation waves were observed at 0.28V and 0.49V for DES and E2. The remarkable signal enlargements indicated that the detection sensitivity was improved significantly. The influences of pH value, amount of graphene and accumulation time on the oxidation signals of DES and E2 were discussed. As a result, a highly-sensitive and rapid electrochemical method was newly developed for simultaneous detection of DES and E2. The values of detection limit were evaluated to be 10.87 nM and 4.9 nM for DES and E2. Additionally, this new method was successfully used in lake water samples and the accuracy was satisfactory.

  3. High-throughput single-cell analysis of low copy number β-galactosidase by a laboratory-built high-sensitivity flow cytometer.

    Science.gov (United States)

    Yang, Lingling; Huang, Tianxun; Zhu, Shaobin; Zhou, Yingxing; Jiang, Yunbin; Wang, Shuo; Chen, Yuqing; Wu, Lina; Yan, Xiaomei

    2013-10-15

    Single-cell analysis is vital in providing insights into the heterogeneity in molecular content and phenotypic characteristics of complex or clonal cell populations. As many essential proteins and most transcription factors are produced at a low copy number, analytical tools with superior sensitivity to enable the analysis of low abundance proteins in single cells are in high demand. β-galactosidase (β-gal) has been the standard cellular reporter for gene expression in both prokaryotic and eukaryotic cells. Here we report the development of a high-throughput method for the single-cell analysis of low copy number β-gal proteins using a laboratory-built high-sensitivity flow cytometer (HSFCM). Upon fluorescence staining with a fluorogenic substrate, quantitative measurements of the basal and near-basal expression of β-gal in single Escherichia coli BL21(DE3) cells were demonstrated. Statistical distribution can be determined quickly by analyzing thousands of individual cells in 1-2min, which reveals the heterogeneous expression pattern that is otherwise masked by the ensemble analysis. Combined with the quantitative fluorometric assay and the rapid bacterial enumeration by HSFCM, the β-gal expression distribution profile could be converted from arbitrary fluorescence units to protein copy numbers per cell. The sensitivity and speed of the HSFCM offers great capability in quantitative analysis of low abundance proteins in single cells, which would help gaining a deeper insight into the heterogeneity and fundamental biological processes in microbial populations.

  4. Aptamer-Functionalized Fluorescent Silica Nanoparticles for Highly Sensitive Detection of Leukemia Cells

    Science.gov (United States)

    Tan, Juntao; Yang, Nuo; Hu, Zixi; Su, Jing; Zhong, Jianhong; Yang, Yang; Yu, Yating; Zhu, Jianmeng; Xue, Dabin; Huang, Yingying; Lai, Zongqiang; Huang, Yong; Lu, Xiaoling; Zhao, Yongxiang

    2016-06-01

    A simple, highly sensitive method to detect leukemia cells has been developed based on aptamer-modified fluorescent silica nanoparticles (FSNPs). In this strategy, the amine-labeled Sgc8 aptamer was conjugated to carboxyl-modified FSNPs via amide coupling between amino and carboxyl groups. Sensitivity and specificity of Sgc8-FSNPs were assessed using flow cytometry and fluorescence microscopy. These results showed that Sgc8-FSNPs detected leukemia cells with high sensitivity and specificity. Aptamer-modified FSNPs hold promise for sensitive and specific detection of leukemia cells. Changing the aptamer may allow the FSNPs to detect other types of cancer cells.

  5. Highly sensitive passive radio frequency identification based sensor systems.

    Science.gov (United States)

    Wissenwasser, J; Vellekoop, M; Heer, R

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments.

  6. Highly sensitive passive radio frequency identification based sensor systems

    Science.gov (United States)

    Wissenwasser, J.; Vellekoop, M.; Heer, R.

    2010-02-01

    A novel platform for sensor applications based on radio frequency (rf) identification technology, where passive tags are powered by the rf-field of a reader, is presented. The sophisticated energy harvesting system of the tag enables a blanking of the rf-field for a defined period, while supplying the tag electronics with a highly stable voltage and a power of 25 mW for 100 ms. During this time, span measurements can be performed without interferences of the rf-field. The presented tags work without batteries and are designed for impedance measurements on microbiological cell cultures under physiological relevant conditions as well as in harsh environments.

  7. Purification of ethanol for highly sensitive self-assembly experiments

    Directory of Open Access Journals (Sweden)

    Kathrin Barbe

    2014-08-01

    Full Text Available Ethanol is the preferred solvent for the formation of self-assembled monolayers (SAMs of thiolates on gold. By applying a thin film sensor system, we could demonstrate that even the best commercial qualities of ethanol contain surface-active contaminants, which can compete with the desired thiolates for surface sites. Here we present that gold nanoparticles deposited onto zeolite X can be used to remove these contaminants by chemisorption. This nanoparticle-impregnated zeolite does not only show high capacities for surface-active contaminants, such as thiols, but can be fully regenerated via a simple pyrolysis protocol.

  8. Dynamics and sensitivity analysis of high-frequency conduction block

    Science.gov (United States)

    Ackermann, D. Michael; Bhadra, Niloy; Gerges, Meana; Thomas, Peter J.

    2011-10-01

    The local delivery of extracellular high-frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: (1) depolarizing currents promote conduction block via inactivation of sodium channels and (2) the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency. Hypothesis 1 was investigated using a combined modeling and experimental study to investigate the effect of depolarizing and hyperpolarizing currents on high-frequency block. The results of the modeling study show that both depolarizing and hyperpolarizing currents play an important role in conduction block and that the conductance to each of three ionic currents increases relative to resting values during HFS. However, depolarizing currents were found to promote the blocking effect, and hyperpolarizing currents were found to diminish the blocking effect. Inward sodium currents were larger than the sum of the outward currents, resulting in a net depolarization of the nodal membrane. Our experimental results support these findings and closely match results from the equivalent modeling scenario: intra-peritoneal administration of the persistent sodium channel blocker ranolazine resulted in an increase in the amplitude of HFS required to produce conduction block in rats, confirming that depolarizing currents promote the conduction block phenomenon. Hypothesis 2 was investigated using a spectral analysis of the channel gating variables in a single-fiber axon model. The results of this study suggested a relationship between the dynamical properties of specific ion channel gating elements and the contributions of corresponding conductances to block onset. Specifically, we show that the dynamics of the fast sodium inactivation gate are

  9. A compact high-sensitivity heterodyne interferometer for industrial metrology

    Science.gov (United States)

    Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Peters, Achim; Johann, Ulrich; Braxmaier, Claus

    2008-04-01

    For translation and tilt metrology, we developed a compact fiber-coupled polarizing heterodyne interferometer which is based on a highly symmetric design where both, measurement and reference beam have similar optical pathlengths and the same frequency and polarization. The method of differential wavefront sensing is implemented for tilt measurement. With this setup we reached noise levels below 5 pm/square root of Hz; Hz in translation and below 10 nrad/square root of Hz; in tilt measurement, both for frequencies above 10-2 Hz. While this setup is developed with respect to the requirements of the LISA (Laser Interferometer Space Antenna) space mission, we here present the current status of its adoption to industrial applications. We currently design a very compact and quasi-monolithic setup of the interferometer sensor head based on ultra-low expansion glass material. The resulting compact and robust sensor head can be used for nano-positioning control. We also plan to implement a scan of the measurement beam over the surface under investigation enabling high resolution 3D profilometry and surface property measurements (i. e. roughness, evenness and roundness). The dedicated low-noise (piezo-electric actuator in the measurement beam of the interferometer will be realized using integrated micro-system technology and can either be implemented in one or two dimensions.

  10. Highly sensitive thermoluminescent carbon doped nanoporous aluminium oxide detectors.

    Science.gov (United States)

    de Azevedo, W M; de Oliveira, G B; da Silva, E F; Khoury, H J; Oliveira de Jesus, E F

    2006-01-01

    In this work we present the synthesis, characterisation and the thermoluminescence (TL) response of nanoporous carbon doped aluminium oxide Al2O3:C produced by anodic oxidation of aluminium in organic and inorganic solvents. The X-ray and scanning electron microscopy (SEM) measurements reveal that the synthesised samples are amorphous and present highly ordered structures with uniform pore distribution with diameter of the order 50 nm. The photoluminescence and spectroscopic analysis in the visible and infrared regions show that the luminescence properties presented by the samples prepared in organic acid are due to carboxylate species, incorporated in anodic alumina films during the synthesis process. After an annealing treatment, part of the incorporated species decomposes and is incorporated into the structure of the aluminium oxide yielding a highly thermoluminescent detector (TL) . The results for X-ray irradiation in the range from 21 to 80 keV indicate a linear TL response with the dose in the range from 5 mGy to 1 Gy, suggesting that nanoporous aluminium oxide produced in the present route of synthesis is a suitable detector for radiation measurements.

  11. Porous tungsten oxide nanoflakes for highly alcohol sensitive performance.

    Science.gov (United States)

    Xiao, J; Liu, P; Liang, Y; Li, H B; Yang, G W

    2012-11-21

    Porous tungsten oxide (WO(3)) nanoflakes have been synthesized by a simple and green approach in an ambient environment. As a precursor solution a polycrystalline hydrated tungstite (H(2)WO(4)·H(2)O) nanoparticles colloid was first prepared by pulsed-laser ablation of a tungsten target in water. The H(2)WO(4)·H(2)O nanoflakes were produced by 72 h aging treatment at room temperature. Finally, porous WO(3) nanoflakes were synthesized by annealing at 800 °C for 4 h. Considering the large surface-to-volume ratio of porous nanoflakes, a porous WO(3) nanoflake gas sensor was fabricated, which exhibits an excellent sensor response performance to alcohol concentrations in the range of 20 to 600 ppm under low working temperature. This high response was attributed to the highly crystalline and porous flake-like morphology, which leads to effective adsorption and desorption, and provides more active sites for the gas molecules' reaction. These findings showed that the porous tungsten oxide nanoflake has great potential in gas-sensing performance.

  12. Highly sensitive temperature sensor based on an isopropanol-filled photonic crystal fiber long period grating

    Science.gov (United States)

    Du, Chao; Wang, Qi; Zhao, Yong; Li, Jin

    2017-03-01

    A high sensitivity measurement method for temperature has been proposed and investigated based on an isopropanol-filled photonic crystal fiber long period grating (PCF-LPG). Due to the high thermo-optic coefficient (TOC) of isopropanol, the sensitivity of the proposed temperature sensor could be effectively improved by filling isopropanol in the air waveguides of PCF. It can be found that the resonant dip will be split in two dips after filling isopropanol and the two dips have different sensitivities to surrounding temperature. Because of PCF-LPG is sensitive to the refractive index (RI) of internal filled liquid, the isopropanol-filled PCF-LPG temperature sensor has a high sensitivities of 1.356 nm/°C in the range of 20-50 °C. The simplicity and the excellent performance of our proposed device make it potential for the applications of high-precision temperature measurement is required.

  13. Analytic continuation and high energy estimates for the resolvent of the Laplacian on forms on asymptotically hyperbolic spaces

    OpenAIRE

    2012-01-01

    We show the analytic continuation of the resolvent of the Laplacian on asymptotically hyperbolic spaces on differential forms, including high energy estimates in strips. This is achieved by placing the spectral family of the Laplacian within the framework developed, and applied to scalar problems, by the author recently, roughly by extending the problem across the boundary of the compactification of the asymptotically hyperbolic space in a suitable manner. The main novelty is that the non-sca...

  14. Highly sensitive and selective detection of phosphate using novel highly photoluminescent water-soluble Mn-doped ZnTe/ZnSe quantum dots.

    Science.gov (United States)

    Song, Yu; Li, Yang; Liu, Yunling; Su, Xingguang; Ma, Qiang

    2015-11-01

    Herein, the facile method with high selectivity for phosphate ion (Pi) sensing using novel Type-II core/shell Mn: ZnTe/ZnSe quantum dots (QDs) was reported. This was the first time that Mn: ZnTe/ZnSe QDs with highlighted optical properties were used for sensing. The water-soluble Mn: ZnTe/ZnSe QDs with a high quantum yield of 7% were synthesized by aqueous synthetic method. Compared with traditional ZnSe QDs or Mn: ZnSe QDs, the smaller effective band gap, longer wavelength and lower ionization potential (high valence band edge) for effective hole localization made Type-II core/shell Mn: ZnTe/ZnSe QDs to be stable and had high photoluminescence (PL). Only Mg(2+) was found to be able to enhance Mn: ZnTe/ZnSe QDs PL selectively. The mechanism of fluorescence enhancement was attributed to the passivated surface nonradiative relaxation centers of Mn: ZnTe/ZnSe QDs. In the presence of Pi anion, the PL intensity got quenched due to the aggregation species of QDs via electrostatic attraction between Pi and Mg(2+) on the surface of Mn: ZnTe/ZnSe QDs. Therefore, the quenching effect can be used to detect Pi selectively. The PL was observed to be linearly proportional to the Pi analyte concentration in the range from 0.67 to 50.0 μmol/L, with a detection limit of 0.2μ mol/L (S/N=3). The novel "on-off" fluorescence nanosensor for Pi detection was sensitive and convenient in the real analysis application. The reported analytical method of Mn: ZnTe/ZnSe QDs is highly sensitive and selective, which can corroborate the extension of its usages in chemo/ biosensing and bioimaging. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. A novel high resolution, high sensitivity SPECT detector for molecular imaging of cardiovascular diseases

    Science.gov (United States)

    Cusanno, F.; Argentieri, A.; Baiocchi, M.; Colilli, S.; Cisbani, E.; De Vincentis, G.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lucentini, M.; Magliozzi, M. L.; Majewski, S.; Marano, G.; Musico, P.; Musumeci, M.; Santavenere, F.; Torrioli, S.; Tsui, B. M. W.; Vitelli, L.; Wang, Y.

    2010-05-01

    Cardiovascular diseases are the most common cause of death in western countries. Understanding the rupture of vulnerable atherosclerotic plaques and monitoring the effect of innovative therapies of heart failure is of fundamental importance. A flexible, high resolution, high sensitivity detector system for molecular imaging with radionuclides on small animal models has been designed for this aim. A prototype has been built using tungsten pinhole and LaBr3(Ce) scintillator coupled to Hamamatsu Flat Panel PMTs. Compact individual-channel readout has been designed, built and tested. Measurements with phantoms as well as pilot studies on mice have been performed, the results show that the myocardial perfusion in mice can be determined with sufficient precision. The detector will be improved replacing the Hamamatsu Flat Panel with Silicon Photomultipliers (SiPMs) to allow integration of the system with MRI scanners. Application of LaBr3(Ce) scintillator coupled to photosensor with high photon detection efficiency and excellent energy resolution will allow dual-label imaging to monitor simultaneously the cardiac perfusion and the molecular targets under investigation during the heart therapy.

  16. Color Sensitivity Multiple Exposure Fusion using High Dynamic Range Image

    Directory of Open Access Journals (Sweden)

    Varsha Borole

    2014-02-01

    Full Text Available In this paper, we present a high dynamic range imaging (HDRI method using a capturing camera image using normally exposure, over exposure and under exposure. We make three different images from a multiple input image using local histogram stretching. Because the proposed method generated three histogram-stretched images from a multiple input image, ghost artifacts that are the result of the relative motion between the camera and objects during exposure time, are inherently removed. Therefore, the proposed method can be applied to a consumer compact camera to provide the ghost artifacts free HDRI. Experiments with several sets of test images with different exposures show that the proposed method gives a better performance than existing methods in terms of visual results and computation time.

  17. Highly sensitive measurements of substrates and inhibitors on the basis of tyrosinase sensors and recycling systems

    Science.gov (United States)

    Streffer, Katrin

    2002-12-01

    compounds in river and sea water and the results could correlated very well with the corresponding DIN-test for the determination of phenolic compounds. An other developed tyrosinasesensor showed a very high sensitiveness for catecholamines, substances which are of special importance in the medical diagnostics. In addition, the investigations of two different tyrosinases, which were carried out also in the context of this thesis, have shown, that a special tyrosinase (tyrosinase from Streptomyces antibioticus) will be the better choice as tyrosinase from Agaricus bisporus, which is used in the area of biosensor research till now, if one wants to develop in future even more sensitive tyrosinasesensors. Furthermore, first successes became reached on a molecular biological field, the production of tyrosinasemutants with special, before well-considered features. These successes can be used to develop a new generation of tyrosinasesensors, tyrosinasesensors in which tyrosinase can be bound directionally both to the corresponding physical pickup or also to another enzyme. From this one expects to achieve ways minimized which the substance to be determined (or whose product) otherwise must cover. Finally, this should result in an clearly visible increase of sensitivity of the Biosensor. Analytische Chemie heute meint nicht länger nur die große Messtechnik, die zeit- und kostenintensiv ist, die außerdem nur von qualifiziertem Personal zu bedienen ist und deren Resultate nur durch dieses Personal auswertbar sind. Meist erfordert diese sagen wir 'klassische analytische Messtechnik' auch noch spezielle Räumlichkeiten und oft eine relative große Menge an speziell vorbereiteten Proben. Neben dieser klassischen analytischen Messtechnik hat sich besonders in den letzten Jahren eine auf bestimmte Stoffgruppen und Anforderungen zugeschnittene Messtechnik durchgesetzt, die oft auch durch einen Laien bedient werden kann. Meist sind es sehr kleine Geräte. Auch die ben

  18. High sensitivity, wide coverage, and high-resolution NIR non-cryogenic spectrograph, WINERED

    Science.gov (United States)

    Ikeda, Yuji; Kobayashi, Naoto; Kondo, Sohei; Otsubo, Shogo; Hamano, Satoshi; Sameshima, Hiroaki; Yoshikawa, Tomoshiro; Fukue, Kei; Nakanishi, Kenshi; Kawanishi, Takafumi; Nakaoka, Tetsuya; Kinoshita, Masaomi; Kitano, Ayaka; Asano, Akira; Takenaka, Keiichi; Watase, Ayaka; Mito, Hiroyuki; Yasui, Chikako; Minami, Atsushi; Izumu, Natsuko; Yamamoto, Ryo; Mizumoto, Misaki; Arasaki, Takayuki; Arai, Akira; Matsunaga, Noriyuki; Kawakita, Hideyo

    2016-08-01

    Near-infrared (NIR) high-resolution spectroscopy is a fundamental observational method in astronomy. It provides significant information on the kinematics, the magnetic fields, and the chemical abundances, of astronomical objects embedded in or behind the highly extinctive clouds or at the cosmological distances. Scientific requirements have accelerated the development of the technology required for NIR high resolution spectrographs using 10 m telescopes. WINERED is a near-infrared (NIR) high-resolution spectrograph that is currently mounted on the 1.3 m Araki telescope of the Koyama Astronomical Observatory in Kyoto-Sangyo University, Japan, and has been successfully operated for three years. It covers a wide wavelength range from 0.90 to 1.35 μm (the z-, Y-, and J-bands) with a spectral resolution of R = 28,000 (Wide-mode) and R = 80,000 (Hires-Y and Hires-J modes). WINERED has three distinctive features: (i) optics with no cold stop, (ii) wide spectral coverage, and (iii) high sensitivity. The first feature, originating from the Joyce proposal, was first achieved by WINERED, with a short cutoff infrared array, cold baffles, and custom-made thermal blocking filters, and resulted in reducing the time for development, alignment, and maintenance, as well as the total cost. The second feature is realized with the spectral coverage of Δλ/λ 1/6 in a single exposure. This wide coverage is realized by a combination of a decent optical design with a cross-dispersed echelle and a large format array (2k x 2k HAWAII- 2RG). The Third feature, high sensitivity, is achieved via the high-throughput optics (>60 %) and the very low noise of the system. The major factors affecting the high throughput are the echelle grating and the VPH cross-disperser with high diffraction efficiencies of 83 % and 86 %, respectively, and the high QE of HAWAII-2RG (83 % at 1.23 μm). The readout noise of the electronics and the ambient thermal background radiation at longer wavelengths could be

  19. Effects of intrinsic magnetostriction on tube-topology magnetoelectric sensors with high magnetic field sensitivity

    Science.gov (United States)

    Gillette, Scott M.; Fitchorov, Trifon; Obi, Ogheneyunume; Jiang, Liping; Hao, Hongbo; Wu, Shuangxia; Chen, Yajie; Harris, Vincent G.

    2014-05-01

    Three quasi-one-dimensional magnetoelectric (ME) magnetic field sensors, each with a different magnetostrictive wire material, were investigated in terms of sensitivity and noise floor. Magnetostrictive Galfenol, iron-cobalt-vanadium, and iron-nickel wires were examined. Sensitivity profiles, hysteresis effects, and noise floor measurements for both optimally biased and zero-biased conditions are presented. The FeNi wire (FN) exhibits high sensitivity (5.36 mV/Oe) at bias fields below 22 Oe and an optimal bias of 10 Oe, whereas FeGa wire (FG) exhibits higher sensitivity (6.89 mW/Oe) at bias fields >22 Oe. The sensor of FeCoV wire (FC) presents relatively low sensitivity (2.12 mV/Oe), due to low magnetostrictive coefficient. Each ME tube-topology sensor demonstrates relatively high sensitivity at zero bias field, which results from a magnetic shape anisotropy and internal strain of the thin magnetostrictive wire.

  20. Silver dendrites decorated filter membrane as highly sensitive and reproducible three dimensional surface enhanced Raman scattering substrates

    Science.gov (United States)

    Zhao, Bin; Lu, Ya; Zhang, Congyun; Fu, Yizheng; Moeendarbari, Sina; Shelke, Sandesh R.; Liu, Yaqing; Hao, Yaowu

    2016-11-01

    We report a novel and flexible surface enhanced Raman scattering (SERS) substrate based on filter membranes decorated with silver dendritic nanostructures. The SERS-active substrate was fabricated via electrodeposition, where hierarchical silver dendrites were uniformly and firmly deposited within and on the top of the porous filter membranes. The morphological evolution of silver dendrites was investigated at different deposition times, and the effect of the components of electrolyte was also studied. Finite difference time domain (FDTD) simulations were performed to reveal the distribution of electric filed when Ag dendrites were illuminated with 785 nm light. Such 3D SERS-active substrate exhibits extremely high sensitivity and excellent reproducibility. Raman signal sensitivity for rhodamine 6G was tested as high as 1 × 10-11 M with 12% average intensity variations at the major Raman peak. Additionally, the as-synthesized robust substrate displays high stability under an ambient condition for several months. This 3D eco-friendly filter membrane-based substrate provides not only high density of SERS hot spots, but also a very large area for capturing target analytes. It has potential applications for the detection of trace organic contaminants in the environment.

  1. Nanowire-templated microelectrodes for high-sensitivity pH detection

    DEFF Research Database (Denmark)

    Antohe, V.A.; Radu, Adrian; Mátéfi-Tempfli, Mária

    2009-01-01

    A highly sensitive pH capacitive sensor has been designed by confined growth of vertically aligned nanowire arrays on interdigited microelectrodes. The active surface of the device has been functionalized with an electrochemical pH transducer (polyaniline). We easily tune the device features...... by combining lithographic techniques with electrochemical synthesis. The reported electrical LC resonance measurements show considerable sensitivity enhancement compared to conventional capacitive pH sensors realized with microfabricated interdigited electrodes. The sensitivity can be easily improved...

  2. Miscibility of Itraconazole-Hydroxypropyl Methylcellulose Blends: Insights with High Resolution Analytical Methodologies.

    Science.gov (United States)

    Purohit, Hitesh S; Taylor, Lynne S

    2015-12-07

    Drug-polymer miscibility is considered to be a prerequisite to achieve an optimally performing amorphous solid dispersion (ASD). Unfortunately, it can be challenging to evaluate drug-polymer miscibility experimentally. The aim of this study was to investigate the miscibility of ASDs of itraconazole (ITZ) and hydroxypropyl methylcellulose (HPMC) using a variety of analytical approaches. The phase behavior of ITZ-HPMC films prepared by solvent evaporation was studied before and after heating. Conventional methodology for miscibility determination, that is, differential scanning calorimetry (DSC), was used in conjunction with emerging analytical techniques, such as fluorescence spectroscopy, fluorescence imaging, and atomic force microscopy coupled with nanoscale infrared spectroscopy and nanothermal analysis (AFM-nanoIR-nanoTA). DSC results showed a single glass transition event for systems with 10% to 50% drug loading, suggesting that the ASDs were miscible, whereas phase separation was observed for all of the films based on the other techniques. The AFM-coupled techniques indicated that the phase separation occurred at the submicron scale. When the films were heated, it was observed that the ASD components underwent mixing. The results provide new insights into the phase behavior of itraconazole-HPMC dispersions and suggest that the emerging analytical techniques discussed herein are promising for the characterization of miscibility and microstructure in drug-polymer systems. The observed differences in the phase behavior in films prepared by solvent evaporation before and after heating also have implications for processing routes and suggest that spray drying/solvent evaporation and hot melt extrusion/melt mixing can result in ASDs with varying extent of miscibility between the drug and the polymer.

  3. Complete analytical solution of electromagnetic field problem of high-speed spinning ball

    Science.gov (United States)

    Reichert, T.; Nussbaumer, T.; Kolar, J. W.

    2012-11-01

    In this article, a small sphere spinning in a rotating magnetic field is analyzed in terms of the resulting magnetic flux density distribution and the current density distribution inside the ball. From these densities, the motor torque and the eddy current losses can be calculated. An analytical model is derived, and its results are compared to a 3D finite element analysis. The model gives insight into the torque and loss characteristics of a solid rotor induction machine setup, which aims at rotating the sphere beyond 25 Mrpm.

  4. Evaluation of a high-throughput peptide reactivity format assay for assessment of the skin sensitization potential of chemicals

    Directory of Open Access Journals (Sweden)

    Chin Lin eWong

    2016-03-01

    Full Text Available The direct peptide reactivity assay (DPRA is a validated method for in vitro assessment of the skin sensitization potential of chemicals. In the present work, we describe a peptide reactivity assay using 96-well plate format and systematically identified the optimal assay conditions for accurate and reproducible classification of chemicals with known sensitizing capacity. The aim of the research is to ensure that the analytical component of the peptide reactivity assay is robust, accurate and reproducible in accordance with criteria that are used for the validation of bioanalytical methods. Analytical performance was evaluated using quality control samples (QCs; heptapeptides at low, medium and high concentrations and incubation of control chemicals (chemicals with known sensitization capacity, weak, moderate, strong, extreme and non-sensitizers with each of three synthetic heptapeptides, viz Cor1-C420 (Ac-NKKCDLF, cysteine- (Ac-RFAACAA and lysine- (Ac-RFAAKAA containing heptapeptides. The optimal incubation temperature for all three heptapeptides was 25°C. Apparent heptapeptide depletion was affected by vial material composition. Incubation of test chemicals with Cor1-C420, showed that peptide depletion was unchanged in polypropylene vials over 3-days storage in an autosampler but this was not the case for borosilicate glass vials. For cysteine-containing heptapeptide, the concentration was not stable by day 3 post-incubation in borosilicate glass vials. Although the lysine-containing heptapeptide concentration was unchanged in both polypropylene and borosilicate glass vials, the apparent extent of lysine-containing heptapeptide depletion by ethyl acrylate, differed between polypropylene (24.7% and glass (47.3% vials. Additionally, the peptide-chemical complexes for Cor1-C420-cinnamaldehyde and cysteine-containing heptapeptide-2,4-dinitrochlorobenzene were partially reversible during 3-days of autosampler storage. These observations further

  5. Hypoxia-sensitive reporter system for high-throughput screening.

    Science.gov (United States)

    Tsujita, Tadayuki; Kawaguchi, Shin-ichi; Dan, Takashi; Baird, Liam; Miyata, Toshio; Yamamoto, Masayuki

    2015-01-01

    The induction of anti-hypoxic stress enzymes and proteins has the potential to be a potent therapeutic strategy to prevent the progression of ischemic heart, kidney or brain diseases. To realize this idea, small chemical compounds, which mimic hypoxic conditions by activating the PHD-HIF-α system, have been developed. However, to date, none of these compounds were identified by monitoring the transcriptional activation of hypoxia-inducible factors (HIFs). Thus, to facilitate the discovery of potent inducers of HIF-α, we have developed an effective high-throughput screening (HTS) system to directly monitor the output of HIF-α transcription. We generated a HIF-α-dependent reporter system that responds to hypoxic stimuli in a concentration- and time-dependent manner. This system was developed through multiple optimization steps, resulting in the generation of a construct that consists of the secretion-type luciferase gene (Metridia luciferase, MLuc) under the transcriptional regulation of an enhancer containing 7 copies of 40-bp hypoxia responsive element (HRE) upstream of a mini-TATA promoter. This construct was stably integrated into the human neuroblastoma cell line, SK-N-BE(2)c, to generate a reporter system, named SKN:HRE-MLuc. To improve this system and to increase its suitability for the HTS platform, we incorporated the next generation luciferase, Nano luciferase (NLuc), whose longer half-life provides us with flexibility for the use of this reporter. We thus generated a stably transformed clone with NLuc, named SKN:HRE-NLuc, and found that it showed significantly improved reporter activity compared to SKN:HRE-MLuc. In this study, we have successfully developed the SKN:HRE-NLuc screening system as an efficient platform for future HTS.

  6. Sensory Processing Sensitivity: Factors of the Highly Sensitive Person Scale and Their relationships to Personality and Subjective Health Complaints.

    Science.gov (United States)

    Listou Grimen, Hanne; Diseth, Åge

    2016-12-01

    The aim of the present study was to examine the factor structure of a Norwegian version of the Highly Sensitive Person Scale (HSPS) and to investigate how sensory processing sensitivity (SPS) is related to personality traits of neuroticism, extraversion, and openness and to subjective health complaints (SHC) in a sample of 167 undergraduate psychology students. The results showed that the variance in a shortened version of the HSPS was best described by three separate factors: ease of excitation (EOE), aesthetic sensitivity (AES), and low sensory threshold (LST). Furthermore, the result showed than an overall SPS factor (EOE, LST, and AES combined) was predicted positively by neuroticism and openness and negatively by extraversion. With respect to SHC, the results showed that EOE and LST were positively associated with psychological health complaints. However, the personality trait of neuroticism contributed more than the SPS factors as predictor of SHC. In conclusion, the present study supported a shortened version of the HSPS and its relation to personality factors and SHC.

  7. Enhanced laboratory sensitivity to variation of the fine-structure constant using highly charged ions.

    Science.gov (United States)

    Berengut, J C; Dzuba, V A; Flambaum, V V

    2010-09-17

    We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time variation of the fine-structure constant α. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest α sensitivities seen in atomic systems.

  8. From Big Data to Meaningful Information with SAS High-Performance Analytics

    Directory of Open Access Journals (Sweden)

    Silvia BOLOHAN

    2013-10-01

    Full Text Available This paper is about the importance of Big Data and What You Can Accomplish with the data that counts. Until recently, organizations have been limited to using subsets of their data, or they were constrained to simplistic analyses because the sheer volumes of data overwhelmed their processing platforms. But, what is the point of collecting and storing terabytes of data if you can't analyze it in full context, or if you have to wait hours or days to get results? On the other hand, not all business questions are better answered by bigger data. How can you make the most of all that data, now and in the future? It is a twofold proposition. You can only optimize your success if you weave analytics into your solution. But you also need analytics to help you manage the data itself. There are several key technologies that can help you get a handle on your big data, and more importantly, extract meaningful value from it.

  9. Highly sensitive surface plasmon resonance chemical sensor based on Goos-Hanchen effects

    Science.gov (United States)

    Yin, Xiaobo; Hesselink, Lambertus

    2006-08-01

    The resonance enhanced Goos-Hanchen shifts at attenuated total internal reflection enables the possibility for highly sensitive surface plasmon resonance sensor. The observed giant displacements result from the singular phase retardation at the resonance where the phase is continuous but changes dramatically. The phenomenon is proposed for chemical sensing and the superior sensitivity is demonstrated.

  10. Crosstalk between adjacent nanopores in a solid-state membrane array for multi-analyte high-throughput biomolecule detection

    Science.gov (United States)

    Raza, Muhammad Usman; Saleem, Sajid; Ali, Waqas; Iqbal, Samir M.

    2016-08-01

    Single nanopores are used to detect a variety of biological molecules. The modulations in ionic current under applied bias across the nanopore contain important information about translocating species, thus providing single analyte detection. These systems are, however, challenged in practical situations where multiple analytes have to be detected at high throughput. This paper presents the analysis of a multi-nanopore system that can be used for the detection of analytes with high throughput. As a scalable model, two nanopores were simulated in a single solid-state membrane. The interactions of the electric fields at the mouths of the individual nanopores were analyzed. The data elucidated the electrostatic properties of the nanopores from a single membrane and provided a framework to calculate the -3 dB distance, akin to the Debye length, from one nanopore to the other. This distance was the minimum distance between the adjacent nanopores such that their individual electric fields did not significantly interact with one another. The results can help in the optimal experimental design to construct solid-state nanopore arrays for any given nanopore size and applied bias.

  11. The sensitivity of past and near-future lunar radio experiments to ultra-high-energy cosmic rays and neutrinos

    Science.gov (United States)

    Bray, J. D.

    2016-04-01

    Various experiments have been conducted to search for the radio emission from ultra-high-energy (UHE) particles interacting in the lunar regolith. Although they have not yielded any detections, they have been successful in establishing upper limits on the flux of these particles. I present a review of these experiments in which I re-evaluate their sensitivity to radio pulses, accounting for effects which were neglected in the original reports, and compare them with prospective near-future experiments. In several cases, I find that past experiments were substantially less sensitive than previously believed. I apply existing analytic models to determine the resulting limits on the fluxes of UHE neutrinos and cosmic rays (CRs). In the latter case, I amend the model to accurately reflect the fraction of the primary particle energy which manifests in the resulting particle cascade, resulting in a substantial improvement in the estimated sensitivity to CRs. Although these models are in need of further refinement, in particular to incorporate the effects of small-scale lunar surface roughness, their application here indicates that a proposed experiment with the LOFAR telescope would test predictions of the neutrino flux from exotic-physics models, and an experiment with a phased-array feed on a large single-dish telescope such as the Parkes radio telescope would allow the first detection of CRs with this technique, with an expected rate of one detection per 140 h.

  12. Review of Analytes of Concern and Sample Methods for Closure of DOE High Level Waste Storage Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, Thomas Russell

    2002-08-01

    Sampling residual waste after tank cleaning and analysis for analytes of concern to support closure and cleaning targets of large underground tanks used for storage of legacy high level radioactive waste (HLW) at Department of Energy (DOE) sites has been underway since about 1995. The DOE Tanks Focus Area (TFA) has been working with DOE tank sites to develop new sampling plans, and sampling methods for assessment of residual waste inventories. This paper discusses regulatory analytes of concern, sampling plans, and sampling methods that support closure and cleaning target activities for large storage tanks at the Hanford Site, the Savannah River Site (SRS), the Idaho National Engineering and Environmental Laboratory (INEEL), and the West Valley Demonstration Project (WVDP).

  13. Review of Analytes of Concern and Sample Methods for Closure of DOE High Level Waste Storage Tanks

    Energy Technology Data Exchange (ETDEWEB)

    Thomas, T.R.

    2002-05-06

    Sampling residual waste after tank cleaning and analysis for analytes of concern to support closure and cleaning targets of large underground tanks used for storage of legacy high level radioactive waste (HLW) at Department of Energy (DOE) sites has been underway since about 1995. The DOE Tanks Focus Area (TFA) has been working with DOE tank sites to develop new sampling plans, and sampling methods for assessment of residual waste inventories. This paper discusses regulatory analytes of concern, sampling plans, and sampling methods that support closure and cleaning target activities for large storage tanks at the Hanford Site, the Savannah River Site (SRS), the Idaho National Engineering and Environmental Laboratory (INEEL), and the West Valley Demonstration Project (WVDP).

  14. Highly sensitive and selective fluoride detection in water through fluorophore release from a metal-organic framework.

    Science.gov (United States)

    Hinterholzinger, Florian M; Rühle, Bastian; Wuttke, Stefan; Karaghiosoff, Konstantin; Bein, Thomas

    2013-01-01

    The detection, differentiation and visualization of compounds such as gases, liquids or ions are key challenges for the design of selective optical chemosensors. Optical chemical sensors employ a transduction mechanism that converts a specific analyte recognition event into an optical signal. Here we report a novel concept for fluoride ion sensing where a porous crystalline framework serves as a host for a fluorescent reporter molecule. The detection is based on the decomposition of the host scaffold which induces the release of the fluorescent dye molecule. Specifically, the hybrid composite of the metal-organic framework NH2-MIL-101(Al) and fluorescein acting as reporter shows an exceptional turn-on fluorescence in aqueous fluoride-containing solutions. Using this novel strategy, the optical detection of fluoride is extremely sensitive and highly selective in the presence of many other anions.

  15. Analysis of ultra-high sensitivity configuration in chip-integrated photonic crystal microcavity bio-sensors

    Energy Technology Data Exchange (ETDEWEB)

    Chakravarty, Swapnajit, E-mail: swapnajit.chakravarty@omegaoptics.com; Hosseini, Amir; Xu, Xiaochuan [Omega Optics, Inc., Austin, Texas 78757 (United States); Zhu, Liang; Zou, Yi [Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States); Chen, Ray T., E-mail: raychen@uts.cc.utexas.edu [Omega Optics, Inc., Austin, Texas 78757 (United States); Department of Electrical and Computer Engineering, University of Texas at Austin, Austin, Texas 78758 (United States)

    2014-05-12

    We analyze the contributions of quality factor, fill fraction, and group index of chip-integrated resonance microcavity devices, to the detection limit for bulk chemical sensing and the minimum detectable biomolecule concentration in biosensing. We analyze the contributions from analyte absorbance, as well as from temperature and spectral noise. Slow light in two-dimensional photonic crystals provide opportunities for significant reduction of the detection limit below 1 × 10{sup −7} RIU (refractive index unit) which can enable highly sensitive sensors in diverse application areas. We demonstrate experimentally detected concentration of 1 fM (67 fg/ml) for the binding between biotin and avidin, the lowest reported till date.

  16. Hafnium dioxide as a dielectric for highly-sensitive waveguide-coupled surface plasmon resonance sensors

    Directory of Open Access Journals (Sweden)

    Kunal Tiwari

    2016-04-01

    Full Text Available Hafnium dioxide has been recognized as an excellent dielectric for microelectronics. However, its usefulness for the surface plasmon based sensors has not yet been tested. Here we investigate its usefulness for waveguide-coupled bi-metallic surface plasmon resonance sensors. Several Ag/HfO2/Au multilayer structure sensors were fabricated and evaluated by optical measurements and computer simulations. The resulting data establish correlations between the growth parameters and sensor performance. The sensor sensitivity to refractive index of analytes is determined to be S n = ∂ θ SPR ∂ n ≥ 4 7 0 . The sensitivity data are supported by simulations, which also predict 314 nm for the evanescent field decay length in air.

  17. Combination of electrochemical, spectrometric and other analytical techniques for high throughput screening of pharmaceutically active compounds.

    Science.gov (United States)

    Suzen, Sibel; Ozkan, Sibel A

    2010-08-01

    Recently, use of electrochemistry and combination of this method with spectroscopic and other analytical techniques are getting one of the important approaches in drug discovery and research as well as quality control, drug stability, determination of physiological activity, measurement of neurotransmitters. Many fundamental physiological processes are depending on oxido-reduction reactions in the body. Therefore, it may be possible to find connections between electrochemical and biochemical reactions concerning electron transfer pathways. Applications of electrochemical techniques to redox-active drug development and studies are one of the recent interests in drug discovery. In this review, the latest developments related to the use of electrochemical techniques in drug research in order to evaluate possible combination spectrometric methods with electrochemical techniques.

  18. A Highly Accurate and Efficient Analytical Approach to Bridge Deck Free Vibration Analysis

    Directory of Open Access Journals (Sweden)

    D.J. Gorman

    2000-01-01

    Full Text Available The superposition method is employed to obtain an accurate analytical type solution for the free vibration frequencies and mode shapes of multi-span bridge decks. Free edge conditions are imposed on the long edges running in the direction of the deck. Inter-span support is of the simple (knife-edge type. The analysis is valid regardless of the number of spans or their individual lengths. Exact agreement is found when computed results are compared with known eigenvalues for bridge decks with all spans of equal length. Mode shapes and eigenvalues are presented for typical bridge decks of three and four span lengths. In each case torsional and non-torsional modes are studied.

  19. Development of two highly sensitive immunoassays for detection of copper ions and a suite of relevant immunochemicals

    Energy Technology Data Exchange (ETDEWEB)

    Zhao Hongwei [College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193 (China); Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Nan Tiegui; Tan Guiyu; Gao Wei; Cao Zhen; Sun Shuo; Li Zhaohu [College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193 (China); Li, Qing X., E-mail: qingl@hawaii.edu [Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Wang Baomin, E-mail: wbaomin@263.com [College of Agronomy and Biotechnology, China Agricultural University, Beijing 100193 (China)

    2011-09-19

    Highlights: {center_dot} Two highly sensitive immunoassays for determination of Cu(II) at sub ppb levels. {center_dot} The heterologous competitive enzyme linked immunosorbent assay for heavy metals. {center_dot} Haptenated protein directly conjugated with HRP can reduce the loss of HRP activity. - Abstract: Availability of highly sensitive assays for metal ions can help monitor and manage the environmental and food contamination. In the present study, a monoclonal antibody against Copper(II)-ethylenediaminetetraacetic acid was used to develop two sensitive ELISAs for Cu(II) analysis. Cobalt(II)-EDTA-BSA was the coating antigen in a heterologous indirect competitive ELISA (hicELISA), whereas Co(II)-EDTA-BSA-horseradish peroxidase (HRP) was the enzyme tracer in a heterologous direct competitive ELISA (hdcELISA). Both ELISAs were validated for detecting the content of Cu(II) in environmental waters. The ELISA data agreed well with those from graphite furnace atomic absorption spectroscopy. The methods of developing the Cu(II) hicELISA and hdcELISA are potentially applicable for developing ELISAs for other metals. The chelator-protein complexes such as EDTA-BSA and EDTA-BSA-HRP can form a suite of metal complexes having the consistent hapten density, location and orientation on the conjugates except the difference of the metal core, which can be used as ideal reagents to investigate the relationship between assay sensitivity and antibody affinities for the haptens and the analytes. The strategy of conjugating a haptenated protein directly with HRP can reduce the loss of HRP activity during the conjugation reaction and thus can be applicable for the development of ELISAs for small molecules.

  20. Cavity-enhanced room-temperature high sensitivity optical Faraday magnetometry

    Science.gov (United States)

    Sun, Hui; Lei, Yaohua; Fan, Shuangli; Zhang, Qiaolin; Guo, Hong

    2017-01-01

    We propose a cavity QED system with two-photon Doppler-free configuration for weak magnetic field detection with high sensitivity at room temperature based on cavity electromagnetically induced transparency. Owing to the destructive interference induced by the control and driving fields, two transparency channels are opened. The Faraday rotation within two transparency channels can be used to detect weak magnetic field with high sensitivity at room temperature. The sensitivity with single photon and multiphoton probe inputs is analyzed. With single photon measurement, our numerical calculations demonstrate that the sensitivity with 3.8nT/√{Hz} and 6.4nT/√{Hz} could be achieved. When we measure the magnetic field with multiphoton input, the sensitivity can be improved to 7.7fT/√{Hz} and 25.6fT/√{Hz} under the realistic experimental conditions.

  1. High-throughput, Highly Sensitive Analyses of Bacterial Morphogenesis Using Ultra Performance Liquid Chromatography.

    Science.gov (United States)

    Desmarais, Samantha M; Tropini, Carolina; Miguel, Amanda; Cava, Felipe; Monds, Russell D; de Pedro, Miguel A; Huang, Kerwyn Casey

    2015-12-25

    The bacterial cell wall is a network of glycan strands cross-linked by short peptides (peptidoglycan); it is responsible for the mechanical integrity of the cell and shape determination. Liquid chromatography can be used to measure the abundance of the muropeptide subunits composing the cell wall. Characteristics such as the degree of cross-linking and average glycan strand length are known to vary across species. However, a systematic comparison among strains of a given species has yet to be undertaken, making it difficult to assess the origins of variability in peptidoglycan composition. We present a protocol for muropeptide analysis using ultra performance liquid chromatography (UPLC) and demonstrate that UPLC achieves resolution comparable with that of HPLC while requiring orders of magnitude less injection volume and a fraction of the elution time. We also developed a software platform to automate the identification and quantification of chromatographic peaks, which we demonstrate has improved accuracy relative to other software. This combined experimental and computational methodology revealed that peptidoglycan composition was approximately maintained across strains from three Gram-negative species despite taxonomical and morphological differences. Peptidoglycan composition and density were maintained after we systematically altered cell size in Escherichia coli using the antibiotic A22, indicating that cell shape is largely decoupled from the biochemistry of peptidoglycan synthesis. High-throughput, sensitive UPLC combined with our automated software for chromatographic analysis will accelerate the discovery of peptidoglycan composition and the molecular mechanisms of cell wall structure determination.

  2. A highly sensitive method for the detection of Chrysanthemum virus B

    Directory of Open Access Journals (Sweden)

    Zhiyong Guan

    2017-03-01

    Conclusion: A highly specific and sensitive nested PCR-based assay has been described for detecting CVB. This new method is highly specific and sensitive for the detection of CVB, which is known to infect chrysanthemum plants in the fields. Further, this protocol has an advantage over traditional methods as it is more cost-effective. This assay is ideal for an early stage diagnosis of the disease.

  3. Integration of a High Sensitivity MEMS Directional Sound Sensor With Readout Electronics

    Science.gov (United States)

    2012-12-01

    ERİŞMİŞ, “ MEMS accelerometers and gyroscopes for inertial measurement units,” M.S. thesis, Middle East Technical University, Cankaya, Ankara, Turkey...HIGH SENSITIVITY MEMS DIRECTIONAL SOUND SENSOR WITH READOUT ELECTRONICS by John D. Roth December 2012 Thesis Advisor: Gamani Karunasiri...3. REPORT TYPE AND DATES COVERED Master’s Thesis 4. TITLE AND SUBTITLE Integration of a High Sensitivity MEMS Directional Sound Sensor with

  4. High-sensitivity Cardiac Troponin Elevation after Electroconvulsive Therapy: A Prospective, Observational Cohort Study.

    Science.gov (United States)

    Duma, Andreas; Pal, Swatilika; Johnston, Joshua; Helwani, Mohammad A; Bhat, Adithya; Gill, Bali; Rosenkvist, Jessica; Cartmill, Christopher; Brown, Frank; Miller, J Philip; Scott, Mitchell G; Sanchez-Conde, Francisco; Jarvis, Michael; Farber, Nuri B; Zorumski, Charles F; Conway, Charles; Nagele, Peter

    2017-04-01

    While electroconvulsive therapy is widely regarded as a lifesaving and safe procedure, evidence regarding its effects on myocardial cell injury is sparse. The objective of this investigation was to determine the incidence and magnitude of new cardiac troponin elevation after electroconvulsive therapy using a novel high-sensitivity cardiac troponin I assay. This was a prospective cohort study in adult patients undergoing electroconvulsive therapy in a single academic center (up to three electroconvulsive therapy treatments per patient). The primary outcome was new high-sensitivity cardiac troponin I elevation after electroconvulsive therapy, defined as an increase of high-sensitivity cardiac troponin I greater than 100% after electroconvulsive therapy compared to baseline with at least one value above the limit of quantification (10 ng/l). Twelve-lead electrocardiogram and high-sensitivity cardiac troponin I values were obtained before and 15 to 30 min after electroconvulsive therapy; in a subset of patients, an additional 2-h high-sensitivity cardiac troponin I value was obtained. The final study population was 100 patients and a total of 245 electroconvulsive therapy treatment sessions. Eight patients (8 of 100; 8%) experienced new high-sensitivity cardiac troponin I elevation after electroconvulsive therapy with a cumulative incidence of 3.7% (9 of 245 treatments; one patient had two high-sensitivity cardiac troponin I elevations), two of whom had a non-ST-elevation myocardial infarction (incidence 2 of 245; 0.8%). Median high-sensitivity cardiac troponin I concentrations did not increase significantly after electroconvulsive therapy. Tachycardia and/or elevated systolic blood pressure developed after approximately two thirds of electroconvulsive therapy treatments. Electroconvulsive therapy appears safe from a cardiac standpoint in a large majority of patients. A small subset of patients with preexisting cardiovascular risk factors, however, may develop new

  5. Ultra-High Field NMR and MRI—The Role of Magnet Technology to Increase Sensitivity and Specificity

    Directory of Open Access Journals (Sweden)

    Ewald Moser

    2017-08-01

    Full Text Available “History, of course, is difficult to write, if for no other reason, than that it has so many players and so many authors.” – P. J. Keating (former Australian Prime MinisterStarting with post-war developments in nuclear magnetic resonance (NMR a race for stronger and stronger magnetic fields has begun in the 1950s to overcome the inherently low sensitivity of this promising method. Further challenges were larger magnet bores to accommodate small animals and eventually humans. Initially, resistive electromagnets with small pole distances, or sample volumes, and field strengths up to 2.35 T (or 100 MHz 1H frequency were used in applications in physics, chemistry, and material science. This was followed by stronger and more stable (Nb-Ti based superconducting magnet technology typically implemented first for small-bore systems in analytical chemistry, biochemistry and structural biology, and eventually allowing larger horizontal-bore magnets with diameters large enough to fit small laboratory animals. By the end of the 1970s, first low-field resistive magnets big enough to accommodate humans were developed and superconducting whole-body systems followed. Currently, cutting-edge analytical NMR systems are available at proton frequencies up to 1 GHz (23.5 T based on Nb3Sn at 1.9 K. A new 1.2 GHz system (28 T at 1.9 K, operating in persistent mode but using a combination of low and high temperature multi-filament superconductors is to be released. Preclinical instruments range from small-bore animal systems with typically 600–800 MHz (14.1–18.8 T up to 900 MHz (21 T at 1.9 K. Human whole-body MRI systems currently operate up to 10.5 T. Hybrid combined superconducting and resistive electromagnets with even higher field strength of 45 T dc and 100 T pulsed, are available for material research, of course with smaller free bore diameters. This rather costly development toward higher and higher field strength is a consequence of the inherently low

  6. Making sense of high sensitivity troponin assays and their role in clinical care.

    Science.gov (United States)

    Daniels, Lori B

    2014-04-01

    Cardiac troponin assays have an established and undisputed role in the diagnosis and risk stratification of patients with acute myocardial infarction. As troponin assays gets more sensitive and more precise, the number of potential uses has rapidly expanded, but the use of this test has also become more complicated and controversial. Highly sensitive troponin assays can now detect troponin levels in most individuals, but accurate interpretation of these levels requires a clear understanding of the assay in the context of the clinical scenario. This paper provides a practical and up-to-date overview of the uses of highly sensitive troponin assays for diagnosis, prognosis, and risk stratification in clinical practice.

  7. High sensitivity probe absorption technique for time-of-flight measurements on cold atoms

    Indian Academy of Sciences (India)

    A K Mohapatra; C S Unnikrishnan

    2006-06-01

    We report on a phase-sensitive probe absorption technique with high sensitivity, capable of detecting a few hundred ultra-cold atoms in flight in an observation time of a few milliseconds. The large signal-to-noise ratio achieved is sufficient for reliable measurements on low intensity beams of cold atoms. We demonstrate the high sensitivity and figure of merit of the simple method by measuring the time-of-flight of atoms moving upwards from a magneto-optical trap released in the gravitational field.

  8. High-overtone Bulk-Acoustic Resonator gravimetric sensitivity: towards wideband acoustic spectroscopy

    CERN Document Server

    Rabus, D; Ballandras, S; Baron, T; Lebrasseur, E; Carry, E

    2015-01-01

    In the context of direct detection sensors with compact dimensions, we investigate the gravimetric sensitivity of High-overtone Bulk Acoustic Resonators, through modeling of their acoustic characteristics and experiment. The high frequency characterizing such devices is expected to induce a significant effect when the acoustic field boundary conditions are modified by a thin adlayer. Furthermore, the multimode spectral characteristics is considered for wideband acoustic spectroscopy of the adlayer, once the gravimetric sensitivity dependence of the various overtones is established. Finally, means of improving the gravimetric sensitivity by confining the acoustic field in a low acoustic-impedance layer is theoretically established.

  9. Quantitative Mass Spectrometry for Bacterial Protein Toxins — A Sensitive, Specific, High-Throughput Tool for Detection and Diagnosis

    Directory of Open Access Journals (Sweden)

    Suzanne Kalb

    2011-03-01

    Full Text Available Matrix-assisted laser-desorption time-of-flight (MALDI-TOF mass spectrometry (MS is a valuable high-throughput tool for peptide analysis. Liquid chromatography electrospray ionization (LC-ESI tandem-MS provides sensitive and specific quantification of small molecules and peptides. The high analytic power of MS coupled with high-specificity substrates is ideally suited for detection and quantification of bacterial enzymatic activities. As specific examples of the MS applications in disease diagnosis and select agent detection, we describe recent advances in the analyses of two high profile protein toxin groups, the Bacillus anthracis toxins and the Clostridium botulinum neurotoxins. The two binary toxins produced by B. anthracis consist of protective antigen (PA which combines with lethal factor (LF and edema factor (EF, forming lethal toxin and edema toxin respectively. LF is a zinc-dependent endoprotease which hydrolyzes specific proteins involved in inflammation and immunity. EF is an adenylyl cyclase which converts ATP to cyclic-AMP. Toxin-specific enzyme activity for a strategically designed substrate, amplifies reaction products which are detected by MALDI-TOF-MS and LC-ESI-MS/MS. Pre-concentration/purification with toxin specific monoclonal antibodies provides additional specificity. These combined technologies have achieved high specificity, ultrasensitive detection and quantification of the anthrax toxins. We also describe potential applications to diseases of high public health impact, including Clostridium difficile glucosylating toxins and the Bordetella pertussis adenylyl cyclase.

  10. A three-dimensional finite-element thermal/mechanical analytical technique for high-performance traveling wave tubes

    Science.gov (United States)

    Shalkhauser, Kurt A.; Bartos, Karen F.; Fite, E. B.; Sharp, G. R.

    1992-01-01

    Current research in high-efficiency, high-performance traveling wave tubes (TWT's) has led to the development of novel thermal/mechanical computer models for use with helical slow-wave structures. A three-dimensional, finite element computer model and analytical technique used to study the structural integrity and thermal operation of a high-efficiency, diamond-rod, K-band TWT designed for use in advanced space communications systems. This analysis focused on the slow-wave circuit in the radiofrequency section of the TWT, where an inherent localized heating problem existed and where failures were observed during earlier cold compression, or 'coining' fabrication technique that shows great potential for future TWT development efforts. For this analysis, a three-dimensional, finite element model was used along with MARC, a commercially available finite element code, to simulate the fabrication of a diamond-rod TWT. This analysis was conducted by using component and material specifications consistent with actual TWT fabrication and was verified against empirical data. The analysis is nonlinear owing to material plasticity introduced by the forming process and also to geometric nonlinearities presented by the component assembly configuration. The computer model was developed by using the high efficiency, K-band TWT design but is general enough to permit similar analyses to be performed on a wide variety of TWT designs and styles. The results of the TWT operating condition and structural failure mode analysis, as well as a comparison of analytical results to test data are presented.

  11. High strain rate sensitivity of hardness in quinary Ti-Zr-Hf-Cu-Ni high entropy metallic glass thin films

    Science.gov (United States)

    Zhao, Shaofan; Wang, Haibin; Xiao, Lin; Guo, Nan; Zhao, Delin; Yao, Kefu; Chen, Na

    2017-10-01

    Quinary Ti-Zr-Hf-Cu-Ni high-entropy metallic glass thin films were produced by magnetron sputter deposition. Nanoindentation tests indicate that the deposited film exhibits a relatively large hardness of 10.4±0.6 GPa and a high elastic modulus of 131±11 GPa under the strain rate of 0.5 s-1. Specifically, the strain rate sensitivity of hardness measured for the thin film is 0.05, the highest value reported for metallic glasses so far. Such high strain rate sensitivity of hardness is likely due to the high-entropy effect which stabilizes the amorphous structure with enhanced homogeneity.

  12. Focused upon hybridization: rapid and high sensitivity detection of DNA using isotachophoresis and peptide nucleic acid probes.

    Science.gov (United States)

    Ostromohov, Nadya; Schwartz, Ortal; Bercovici, Moran

    2015-09-15

    We present a novel assay for rapid and high sensitivity detection of nucleic acids without amplification. Utilizing the neutral backbone of peptide nucleic acids (PNA), our method is based on the design of low electrophoretic mobility PNA probes, which do not focus under isotachophoresis (ITP) unless bound to their target sequence. Thus, background noise associated with free probes is entirely eliminated, significantly improving the signal-to-noise ratio while maintaining a simple single-step assay requiring no amplification steps. We provide a detailed analytical model and experimentally demonstrate the ability to detect targets as short as 17 nucleotides (nt) and a limit of detection of 100 fM with a dynamic range of 5 decades. We also demonstrate that the assay can be successfully implemented for detection of DNA in human serum without loss of signal. The assay requires 15 min to complete, and it could potentially be used in applications where rapid and highly sensitive amplification-free detection of nucleic acids is desired.

  13. A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step.

    Science.gov (United States)

    Santos, Felisberto G; Reis, Boaventura F

    2017-01-01

    A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V) with thiocyanate ions (SCN(-)) in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm) to achieve high sensitivity, allowing Mo(V) determination at a level of μg L(-1) without the use of an organic solvent extraction step. After optimization of operational conditions, samples of digested plant materials were analyzed employing the proposed procedure. The accuracy was assessed by comparing the obtained results with those of a reference method, with an agreement observed at 95% confidence level. In addition, a detection limit of 9.1 μg L(-1), a linear response (r = 0.9969) over the concentration range of 50-500 μg L(-1), generation of only 3.75 mL of waste per determination, and a sampling rate of 51 determinations per hour were achieved.

  14. A Highly Sensitive Multicommuted Flow Analysis Procedure for Photometric Determination of Molybdenum in Plant Materials without a Solvent Extraction Step

    Directory of Open Access Journals (Sweden)

    Felisberto G. Santos

    2017-01-01

    Full Text Available A highly sensitive analytical procedure for photometric determination of molybdenum in plant materials was developed and validated. This procedure is based on the reaction of Mo(V with thiocyanate ions (SCN− in acidic medium to form a compound that can be monitored at 474 nm and was implemented employing a multicommuted flow analysis setup. Photometric detection was performed using an LED-based photometer coupled to a flow cell with a long optical path length (200 mm to achieve high sensitivity, allowing Mo(V determination at a level of μg L−1 without the use of an organic solvent extraction step. After optimization of operational conditions, samples of digested plant materials were analyzed employing the proposed procedure. The accuracy was assessed by comparing the obtained results with those of a reference method, with an agreement observed at 95% confidence level. In addition, a detection limit of 9.1 μg L−1, a linear response (r=0.9969 over the concentration range of 50–500 μg L−1, generation of only 3.75 mL of waste per determination, and a sampling rate of 51 determinations per hour were achieved.

  15. A Study on Theoretical Performance of Graphene FET using Analytical Approach with Reference to High Cutoff Frequency

    Science.gov (United States)

    Fahim-Al-Fattah, Md.; Rahman, Md. Tawabur; Islam, Md. Sherajul; Bhuiyan, Ashraful G.

    2016-02-01

    This paper presents a detailed study of theoretical performance of graphene field effect transistor (GFET) using analytical approach. GFET shows promising performance in terms of faster saturation as well as extremely high cutoff frequency (3.9THz). A significant shift of the Dirac point as well as an asymmetrical ambipolar behavior is observed on the transfer characteristics. Similarly, an approximate symmetrical capacitance-voltage (C-V) characteristics is obtained where it has guaranteed the consistency because it shows a significant saturation both in the accumulation and inversion region. In addition, a high transconductance of 6800uS at small channel length (20nm) along with high cutoff frequency (3.9THz) has been observed which demands for high speed field effect devices.

  16. Highly Sensitive Local Surface Plasmon Resonance in Anisotropic Au Nanoparticles Deposited on Nanofibers

    Directory of Open Access Journals (Sweden)

    Masanari Saigusa

    2015-01-01

    Full Text Available This paper reports the facile and high-throughput fabrication method of anisotropic Au nanoparticles with a highly sensitive local surface plasmon resonance (LPR using cylindrical nanofibers as substrates. The substrates consisting of nanofibers were prepared by the electrospinning of poly(vinylidene fluoride (PVDF. The Au nanoparticles were deposited on the surface of electrospun nanofibers by vacuum evaporation. Scanning electron microscopy revealed the formation of a curved Au island structure on the surface of cylindrical nanofibers. Polarized UV-visible extinction spectroscopy showed anisotropy in their LPR arising from the high surface curvature of the nanofiber. The LPR of the Au nanoparticles on the thinnest nanofiber with a diameter of ~100 nm showed maximum refractive index (RI sensitivity over 500 nm/RI unit (RIU. The close correlation between the fiber diameter dependence of the RI sensitivity and polarization dependence of the LPR suggests that anisotropic Au nanoparticles improve RI sensitivity.

  17. Fano resonance-based highly sensitive, compact temperature sensor on thin film lithium niobate.

    Science.gov (United States)

    Qiu, Wentao; Ndao, Abdoulaye; Vila, Venancio Calero; Salut, Roland; Courjal, Nadège; Baida, Fadi Issam; Bernal, Maria-Pilar

    2016-03-15

    In this Letter, we report a Fano resonance-based highly sensitive and compact temperature sensor fabricated on thin film lithium niobate (TFLN) Suzuki phase lattice (SPL) photonic crystal. The experimental sensitivity is estimated to be 0.77 nm/°C with a photonic crystal size of only 25  μm × 24  μm. This sensitivity is 38 times larger than the intrinsic one of lithium niobate which is 0.02 nm/°C. The demonstrated sharp and high extinction ratio characteristics of the Fano lineshape resonance could be an excellent candidate in developing a high sensitivity temperature sensor, electric field sensor, etc.

  18. Comparison of excitation mechanisms in the analytical regions of a high-power two-jet plasma

    Energy Technology Data Exchange (ETDEWEB)

    Zaksas, Natalia P., E-mail: zak@niic.nsc.ru

    2015-07-01

    Excitation mechanisms in the analytical regions of a high-power two-jet plasma were investigated. A new plasmatron recently developed was applied in this work. The Boltzmann population of excited levels of Fe atoms and ions was observed in both analytical regions, before and after the jet confluence, as well as in the jet confluence, which proves excitation of atoms and ions by electron impact. The disturbance of local thermodynamic equilibrium in all regions of the plasma flow was deduced on the basis of considerable difference in Fe atomic and ionic excitation temperatures. Such a difference is most likely to be caused by contribution of metastable argon to atom ionization. The region before the jet confluence has the greatest difference in Fe atomic and ionic excitation temperatures and is more non-equilibrium than the region after the confluence due to comparatively low electron and high metastable argon concentrations. Low electron concentration in this region provides lower background emission than in the region after the jet confluence, which leads to better detection limits for the majority of elements. - Highlights: • Excitation mechanisms were investigated in the analytical regions of a high-power TJP. • Boltzmann population of excited levels of Fe atoms and ions takes place in all regions of the plasma flow. • The considerable difference in Fe atomic and ionic excitation temperatures occurs. • Penning ionization by metastable argon results in disturbance of LTE in the plasma. • The region before the jet confluence is more non-equilibrium than after that.

  19. Combined liver and kidney transplantation in a highly sensitized and positively cross-matched patient

    Directory of Open Access Journals (Sweden)

    Salem Alqurashi

    2011-01-01

    Full Text Available Combined liver kidney transplantation (CLKT has been used on many occasions and proved to be a successful event for both liver and kidney in highly sensitized patients. Our aim was to review the immunological and other laboratory results of a CLKT in a highly sensitized patient. CLKT was used to treat a highly sensitized, 42-year-old female. She was suffering from end-stage liver disease due to hepatitis C virus (HCV infection and renal disease due to diabetic nephropathy. Cross-matching, panel reactive assay (PRA and routine laboratory tests for liver and renal function were carried out before and after the CLKT. Prior to the CLKT, the patient was highly sensitized with human leukocytes antigens (anti-HLA class I antibodies (>90%. Patient was offered CLKT from a deceased donor. She had donor-specific antibodies, class I and II. Both T and B CDC cross-matches (XM were positive pre-transplant and eight hours post-transplant. Both cross-match and PRA results became completely negative six days post CKLT. Almost 30 months post CLKT, her renal function is normal and negative for class I and II PRA. Liver graft appears to be protective for renal graft when they are combined even in highly sensitized patients. CLKT is very useful in overcoming sensitization in addition to treating end-stage liver and renal diseases.

  20. Radial heterogeneity of some analytical columns used in high-performance liquid chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Mriziq, Khaled S [ORNL; Guiochon, Georges A [ORNL

    2009-01-01

    An on-column electrochemical microdetector was used to determine accurately the radial distribution of the mobile phase velocity and of the column efficiency at the exit of three common analytical columns, namely a 100 mm x 4.6 mm C18 bonded silica-based monolithic column, a 150 mm x 4.6 mm column packed with 2.7 {micro}m porous shell particles of C18 bonded silica (HALO), and a 150 mm x 4.6 mm column packed with 3 {micro}m fully porous C18 bonded silica particles (LUNA). The results obtained demonstrate that all three columns are not radially homogeneous. In all three cases, the efficiency was found to be lower in the wall region of the column than in its core region (the central core with a radius of 1/3 the column inner radius). The decrease in local efficiency from the core to the wall regions was lower in the case of the monolith (ca. 25%) than in that of the two particle-packed columns (ca. 35-50%). The mobile phase velocity was found to be ca. 1.5% higher in the wall than in the core region of the monolithic column while, in contrast, it was ca. 2.5-4.0% lower in the wall region for the two particle-packed columns.

  1. Simple Analytic Expression with High Precision for the Barker-Henderson Diameter

    Institute of Scientific and Technical Information of China (English)

    孙久勋

    2003-01-01

    A fitting procedure is proposed to establish two analytic approximate expressions for the complicated Barker-Henderson (BH) diameter with Lennard-Jones potential in two temperature ranges. Considering that the differentiation is a process enlarging the errors and the integration decreasing the errors and that the derivative of BH diameter is important in the calculation of internal energy, we propose to fit the derivative directly, instead of usually fitting the original function and subsequently deriving its derivative. The simplicity and precision of two expressions developed are superior to the extensively used expressions in literature. The one with following form only has an average fitting 0.0063% in the reduced temperature range (0.4 ≤ kT/ε≤ 15), and can be extrapolated to a wider temperature range (0.4 ≤ kT/ε≤ 50) with an average error 0.13%, which is d/σ = 1.1755 + 0.02878 lnτ - 0.2072τ1/4 + 0.00463τ3/4.

  2. Critical assessment of three high performance liquid chromatography analytical methods for food carotenoid quantification.

    Science.gov (United States)

    Dias, M Graça; Oliveira, Luísa; Camões, M Filomena G F C; Nunes, Baltazar; Versloot, Pieter; Hulshof, Paul J M

    2010-05-21

    Three sets of extraction/saponification/HPLC conditions for food carotenoid quantification were technically and economically compared. Samples were analysed for carotenoids alpha-carotene, beta-carotene, beta-cryptoxanthin, lutein, lycopene, and zeaxanthin. All methods demonstrated good performance in the analysis of a composite food standard reference material for the analytes they are applicable to. Methods using two serial connected C(18) columns and a mobile phase based on acetonitrile, achieved a better carotenoid separation than the method using a mobile phase based on methanol and one C(18)-column. Carotenoids from leafy green vegetable matrices appeared to be better extracted with a mixture of methanol and tetrahydrofuran than with tetrahydrofuran alone. Costs of carotenoid determination in foods were lower for the method with mobile phase based on methanol. However for some food matrices and in the case of E-Z isomer separations, this was not technically satisfactory. Food extraction with methanol and tetrahydrofuran with direct evaporation of these solvents, and saponification (when needed) using pyrogallol as antioxidant, combined with a HPLC system using a slight gradient mobile phase based on acetonitrile and a stationary phase composed by two serial connected C(18) columns was the most technically and economically favourable method.

  3. Interpersonal sensitivity and functioning impairment in youth at ultra-high risk for psychosis.

    Science.gov (United States)

    Masillo, A; Valmaggia, L R; Saba, R; Brandizzi, M; Lindau, J F; Solfanelli, A; Curto, M; Narilli, F; Telesforo, L; Kotzalidis, G D; Di Pietro, D; D'Alema, M; Girardi, P; Fiori Nastro, P

    2016-01-01

    A personality trait that often elicits poor and uneasy interpersonal relationships is interpersonal sensitivity. The aim of the present study was to explore the relationship between interpersonal sensitivity and psychosocial functioning in individuals at ultra-high risk for psychosis as compared to help-seeking individuals who screened negative for an ultra-high risk of psychosis. A total sample of 147 adolescents and young adult who were help seeking for emerging mental health problems participated in the study. The sample was divided into two groups: 39 individuals who met criteria for an ultra-high-risk mental state (UHR), and 108 (NS). The whole sample completed the Interpersonal Sensitivity Measure (IPSM) and the Global Functioning: Social and Role Scale (GF:SS; GF:RS). Mediation analysis was used to explore whether attenuated negative symptoms mediated the relationship between interpersonal sensitivity and social functioning. Individuals with UHR state showed higher IPSM scores and lower GF:SS and GF:RS scores than NS participants. A statistically negative significant correlation between two IPSM subscales (Interpersonal Awareness and Timidity) and GF:SS was found in both groups. Our results also suggest that the relationship between the aforementioned aspects of interpersonal sensitivity and social functioning was not mediated by negative prodromal symptoms. This study suggests that some aspects of interpersonal sensitivity were associated with low level of social functioning. Assessing and treating interpersonal sensitivity may be a promising therapeutic target to improve social functioning in young help-seeking individuals.

  4. Full validation and application of an ultra high performance liquid chromatographic-tandem mass spectrometric procedure for target screening and quantification of 34 antidepressants in human blood plasma as part of a comprehensive multi-analyte approach.

    Science.gov (United States)

    Remane, Daniela; Meyer, Markus R; Wissenbach, Dirk K; Maurer, Hans H

    2011-06-01

    Multi-analyte procedures are of great interest in clinical and forensic toxicology making the analytical process much simpler, faster, and cheaper and allow monitoring of analytes of different drug classes in one single body sample. The aim of the present study was to validate an ultra high performance liquid chromatographic-tandem mass spectrometric approach for fast target screening and quantification of 34 antidepressants in plasma after simple liquid-liquid extraction as part of a multi-analyte procedure for over 130 drugs. The validation process including recovery, matrix effects, process efficiency, ion suppression/enhancement of co-eluting analytes (already published), selectivity, cross talk, accuracy and precision, stabilities, and limits of quantification and detection showed that the approach was selective, sensitive, accurate, and precise for 28 of the 34 tested drugs. The applicability was successfully tested by analyzing authentic plasma samples and external quality control samples. Furthermore, it could be shown that time- and cost-saving one-point calibration was applicable for 21 drugs for daily routine and especially in emergency cases.

  5. Ultra high performance liquid chromatographic-tandem mass spectrometric multi-analyte procedure for target screening and quantification in human blood plasma: validation and application for 31 neuroleptics, 28 benzodiazepines, and Z-drugs.

    Science.gov (United States)

    Remane, Daniela; Meyer, Markus R; Wissenbach, Dirk K; Maurer, Hans H

    2011-09-01

    For fast and reliable screening, identification, and quantification of as many analytes as possible, multi-analyte approaches are very useful in clinical and forensic toxicology. Using ultra high performance liquid chromatography-tandem mass spectrometry, such an approach has been developed for blood plasma analysis after simple liquid-liquid extraction. In the present paper, validation and application is described for 31 neuroleptics, 28 benzodiazepines, and Z-drugs (zaleplone, zolpidem, and zopiclone). The validation parameters included recovery, matrix effects, process efficiency, ion suppression/enhancement of co-eluting analytes, selectivity, crosstalk, accuracy and precision, stabilities, and limits of quantification and detection. The results showed that the approach was selective, sensitive, accurate, and precise for 24 neuroleptics and 21 benzodiazepines and Z-drugs. The remaining analytes were unstable and/or too low dosed. Cost- and time-saving one-point calibration was applicable only for half of the analytes. The applicability was successfully shown for most of the drugs by analyzing authentic plasma samples and external quality control samples.

  6. Bridge Technology with TSH Receptor Chimera for Sensitive Direct Detection of TSH Receptor Antibodies Causing Graves' Disease: Analytical and Clinical Evaluation.

    Science.gov (United States)

    Frank, C U; Braeth, S; Dietrich, J W; Wanjura, D; Loos, U

    2015-11-01

    Graves' disease is caused by stimulating autoantibodies against the thyrotropin receptor inducing uncontrolled overproduction of thyroid hormones. A Bridge Assay is presented for direct detection of these thyroid-stimulating immunoglobulins using thyrotropin receptor chimeras. A capture receptor, formed by replacing aa residues 261-370 of the human thyrotropin receptor with residues 261-329 from rat lutropin/choriogonadotropin receptor and fixed to microtiter plates, binds one arm of the autoantibody. The second arm bridges to the signal receptor constructed from thyrotropin receptor (aa 21-261) and secretory alkaline phosphatase (aa 1-519) inducing chemiluminescence. The working range of the assay is from 0.3 IU/l to 50 IU/l with a cutoff of 0.54 IU/l and functional sensitivity of 0.3 IU/l. Sensitivity and specificity are 99.8 and 99.1%, respectively, with a diagnostic accuracy of 0.998. The low grey zone is from 0.3-0.54 IU/l. The stimulatory character of the assayed antibodies is shown through a good correlation (r=0.7079, pGraves' disease, titers are increased in associated eye disease. In 3 hypothyroid patients with sera positive in the thyrotropin receptor competition assay and in the blocking bioassay, antibodies are not detected by the Bridge Assay, while the monoclonal blocking antibody K1-70 was detected. In Hashimoto disease thyrotropin receptor autoantibodies are detected in some patients, but not in goiter. This Bridge Assay delivers good diagnostic accuracy for identification of Graves' disease patients. Its high sensitivity may facilitate early detection of onset, remission, or recurrence of Graves' disease enabling timely adaption of the treatment.Human genes: TSHR, Homo sapiens, acc. no. M31774.1.

  7. Analytical Estimation of Carrier Phase Recovery Approaches in Long-Haul High-Speed Optical Communication Systems

    CERN Document Server

    Xu, Tianhua

    2016-01-01

    The analytical study on the carrier phase estimation (CPE) approaches, involving a one-tap normalized least-mean-square (NLMS) algorithm, a block-wise average (BWA) algorithm, and a Viterbi-Viterbi (VV) algorithm has been investigated in the long-haul high-speed n-level phase shift keying (n-PSK) coherent optical fiber communication systems. The close-form predictions for the bit-error-rate (BER) performance have been derived and analyzed by considering both the intrinsic laser phase noise and the equalization enhanced phase noise (EEPN).

  8. Proposed helmet PET geometries with add-on detectors for high sensitivity brain imaging

    Science.gov (United States)

    Tashima, Hideaki; Yamaya, Taiga

    2016-10-01

    For dedicated brain PET, we can significantly improve sensitivity for the cerebrum region by arranging detectors in a compact hemisphere. The geometrical sensitivity for the top region of the hemisphere is increased compared with conventional cylindrical PET consisting of the same number of detectors. However, the geometrical sensitivity at the center region of the hemisphere is still low because the bottom edge of the field-of-view is open, the same as for the cylindrical PET. In this paper, we proposed a helmet PET with add-on detectors for high sensitivity brain PET imaging for both center and top regions. The key point is the add-on detectors covering some portion of the spherical surface in addition to the hemisphere. As the location of the add-on detectors, we proposed three choices: a chin detector, ear detectors, and a neck detector. For example, the geometrical sensitivity for the region-of-interest at the center was increased by 200% by adding the chin detector which increased the size by 12% of the size of the hemisphere detector. The other add-on detectors gave almost the same increased sensitivity effect as the chin detector did. Compared with standard whole-body-cylindrical PET, the proposed geometries can achieve 2.6 times higher sensitivity for brain region even with less than 1/4 detectors. In addition, we conducted imaging simulations for geometries with a diameter of 250 mm and with high resolution depth-of-interaction detectors. The simulation results showed that the proposed geometries increased image quality, and all of the add-on detectors were equivalently effective. In conclusion, the proposed geometries have high potential for widespread applications in high-sensitivity, high-resolution, and low-cost brain PET imaging.

  9. High-sensitivity and high-Q-factor glass photonic crystal cavity and its applications as sensors.

    Science.gov (United States)

    Siraji, Ashfaqul Anwar; Zhao, Yang

    2015-04-01

    We investigate the properties of a planar photonic crystal cavity on glass and its applications as sensors. An airbridged twofold defect cavity on Schott glass background and Gorilla glass substrate has been designed for high Q-factor up to 4459. The average sensitivity of the cavity resonance to background refractive index is 388 nm/Refractive Index Unit. The resonant wavelength is sensitive to background temperature by 18.5 pm/°C. The designed sensors show much higher sensitivity than those based on waveguide interferometers or photonic bandgap structures without cavity resonance. The results are also useful for experimental studies of glass photonic devices.

  10. Fully printed, highly sensitive multifunctional artificial electronic whisker arrays integrated with strain and temperature sensors.

    Science.gov (United States)

    Harada, Shingo; Honda, Wataru; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

    2014-04-22

    Mammalian-mimicking functional electrical devices have tremendous potential in robotics, wearable and health monitoring systems, and human interfaces. The keys to achieve these devices are (1) highly sensitive sensors, (2) economically fabricated macroscale devices on flexible substrates, and (3) multifunctions beyond mammalian functions. Although highly sensitive artificial electronic devices have been reported, none have been fabricated using cost-effective macroscale printing methods and demonstrate multifunctionalities of artificial electronics. Herein we report fully printed high-sensitivity multifunctional artificial electronic whiskers (e-whisker) integrated with strain and temperature sensors using printable nanocomposite inks. Importantly, changing the composition ratio tunes the sensitivity of strain. Additionally, the printed temperature sensor array can be incorporated with the strain sensor array beyond mammalian whisker functionalities. The sensitivity for the strain sensor is impressively high (∼59%/Pa), which is the best sensitivity reported to date (>7× improvement). As the proof-of-concept for a truly printable multifunctional artificial e-whisker array, two- and three-dimensional space and temperature distribution mapping are demonstrated. This fully printable flexible sensor array should be applicable to a wide range of low-cost macroscale electrical applications.

  11. Longevity Tests of High-Sensitivity BD-PND Bubble Dosimeters

    Energy Technology Data Exchange (ETDEWEB)

    Radev, R; Carlberg, E

    2002-07-09

    Medium- and very-high-sensitivity neutron bubble dosimeters (BD-PNDs) made by Bubble Technology Industries (BTI) were used to study the life span of such dosimeters in a standard setup with a {sup 252}Cf source. Although data on the longevity of bubble dosimeters with low and medium sensitivity exist, such data for dosimeters with high and very high sensitivity are not readily available. The manufacturer guarantees optimum dosimeter performance for 3 months after receipt. However, it is important to know the change in the dosimeters' characteristics with time, especially after the first 3 months. The long-term performance of four sets of very high sensitivity and one set of medium-sensitivity bubble dosimeters was examined for periods of up to 13 months. During that time, the detectors were exposed and reset more than 20 times. Although departures from initial detection sensitivity were observed in several cases, the detectors indicated a significantly longer life span than stated in the manufacturer's warranty. In addition, the change in the number of bubbles and in evaluated neutron dose as a function of the time from the end of exposure until the dosimeters were read was investigated.

  12. Is sensitivity to reward associated with the malleability of implicit inclinations toward high-fat food?

    Science.gov (United States)

    Ashby, Casey R; Stritzke, Werner G K

    2013-08-01

    Two experiments examined the effect of positive and negative priming on implicit approach and avoidance inclinations toward high-fat food stimuli in participants high or low in reward sensitivity, using personalized unipolar variants of the Implicit Association Test (IAT; A. G. Greenwald, D. E. McGhee, & J. L. K. Schwartz, 1998, "Measuring individual differences in implicit cognition: The Implicit Association Test," Journal of Personality and Social Psychology, Vol. 74, pp. 1464-1480). Participants high in reward sensitivity showed an automatic processing bias that is characterized by a dual vulnerability of being particularly susceptible to priming of the rewarding aspects of high-fat foods, while being unaffected by priming of the negative aspects of those foods. In contrast, participants low in reward sensitivity generally showed no facilitation of implicit-approach inclinations following positive priming, but consistently showed facilitation of implicit-avoidance inclinations following negative priming. These results are consistent with the revised reinforcement sensitivity theory ( J. A. Gray & N. McNaughton, 2000, The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system, 2nd ed., New York, NY, Oxford University Press.) and suggest that the systems mediating reward sensitivity and punishment sensitivity are not orthogonal, as predicted by the separable subsystems hypothesis, but can be interdependent, as predicted by the joint subsystems hypothesis.

  13. High maltose sensitivity of sweet taste receptors in the Japanese macaque (Macaca fuscata)

    Science.gov (United States)

    Nishi, Emiko; Tsutsui, Kei; Imai, Hiroo

    2016-01-01

    Taste sensitivity differs among animal species depending on feeding habitat. To humans, sucrose is one of the sweetest natural sugars, and this trait is expected to be similar in other primates. However, previous behavioral tests have shown that some primate species have equal preferences for maltose and sucrose. Because sweet tastes are recognized when compounds bind to the sweet taste receptor Tas1R2/Tas1R3, we evaluated the responses of human and Japanese macaque Tas1R2/Tas1R3 to various natural sugars using a heterologous expression system. Human Tas1R2/Tas1R3 showed high sensitivity to sucrose, as expected; however, Japanese macaque Tas1R2/Tas1R3 showed equally high sensitivity to maltose and sucrose. Furthermore, Japanese macaques showed equally high sensitivity to sucrose and maltose in a two-bottle behavioral experiment. These results indicate that Japanese macaques have high sensitivity to maltose, and this sensitivity is directly related to Tas1R2/Tas1R3 function. This is the first molecular biological evidence that for some primate species, sucrose is not the most preferable natural sugar, as it is for humans. PMID:27982108

  14. AN ANALYTIC APPROACH TO THEORETICAL MODELING OF HIGHLY UNSTEADY VISCOUS FLOW EXCITED BY WING FLAPPING IN SMALL INSECTS

    Institute of Scientific and Technical Information of China (English)

    余永亮; 童秉纲; 马晖扬

    2003-01-01

    Numerous studies on the aerodynamics of insect wing flapping were carried out on different approaches of flight investigations, model experiments, and numerical simulations, but the theoretical modeling remains to be explored. In the present paper, an analytic approach is presented to model the flow interactions of wing flapping in air for small insects with the surrounding flow fields being highly unsteady and highly viscous. The model of wing flapping is a 2-D flat plate, which makes plunging and pitching oscillations as well as quick rotations reversing its positions of leading and trailing edges, respectively, during stroke reversals. It contains three simplified aerodynamic assumptions:(i) unsteady potential flow; (ii) discrete vortices shed from both leading and trailing edges of the wing; (iii) Kutta conditions applied at both edges. Then the problem is reduced to the solution of the unsteady Laplace equation, by using distributed singularities, i.e., sources/sinks, and vortices in the field. To validate the present physical model and analytic method proposed via benchmark examples, two elemental motions in wing flapping and a case of whole flapping cycles are analyzed,and the predicted results agree well with available experimental and numerical data. This verifies that the present analytical approach may give qualitatively correct and quantitatively reasonable results.Furthermore, the total fluid-dynamic force in the present method can be decomposed into three parts:one due to the added inertial (or mass) effect, the other and the third due to the induction of vortices shed from the leading- and the trailing-edge and their images respectively, and this helps to reveal the flow control mechanisms in insect wing flapping.

  15. Comprehensive analytical strategy for biomonitoring of pesticides in urine by liquid chromatography–orbitrap high resolution masss pectrometry.

    Science.gov (United States)

    Roca, M; Leon, N; Pastor, A; Yusà, V

    2014-12-29

    In this study we propose an analytical strategy that combines a target approach for the quantitative analysis of contemporary pesticide metabolites with a comprehensive post-target screening for the identification of biomarkers of exposure to environmental contaminants in urine using liquid chromatography coupled to high-resolution mass spectrometry (LC–HRMS). The quantitative method for the target analysis of 29 urinary metabolites of organophosphate (OP) insecticides, synthetic pyrethroids, herbicides and fungicides was validated after a previous statistical optimization of the main factors governing the ion source ionization and a fragmentation study using the high energy collision dissociation (HCD) cell. The full scan accurate mass data were acquired with a resolving power of 50,000 FWHM (scan speed, 2 Hz), in both ESI+ and ESI− modes, and with and without HCD-fragmentation. The method – LOQ was lower than 3.2 μg L−1 for the majority of the analytes. For post-target screening a customized theoretical database was built, for the identification of 60 metabolites including pesticides, PAHs, phenols, and other metabolites of environmental pollutants. For identification purposes, accurate exact mass with less than 5 ppm, and diagnostic ions including isotopes and/or fragments were used. The analytical strategy was applied to 20 urine sample collected from children living in Valencia Region. Eleven target metabolites were detected with concentrations ranging from 1.18 to 131 μg L−1. Likewise, several compounds were tentatively identified in the post-target analysis belonging to the families of phthalates, phenols and parabenes. The proposed strategy is suitable for the determination of target pesticide biomarkers in urine in the framework of biomonitoring studies, and appropriate for the identification of other non-target metabolites.

  16. A two-dimensional threshold voltage analytical model for metal-gate/high-k/SiO2/Si stacked MOSFETs

    Institute of Scientific and Technical Information of China (English)

    Ma Fei; Liu Hong-Xia; Fan Ji-Bin; Wang Shu-Long

    2012-01-01

    In this paper the influences of the metal-gate and high-k/SiO2/Si stacked structure on the metal-oxidesemiconductor field-effect transistor (MOSFET) axe investigated.The flat-band voltage is revised by considering the influences of stacked structure and metal-semiconductor work function fluctuation. The two-dimensional Poisson's equation of potential distribution is presented.A threshold voltage analytical model for metal-gate/high-k/SiO2/Si stacked MOSFETs is developed by solving these Poisson's equations using the boundary conditions.The model is verified by a two-dimensional device simulator,which provides the basic design guidance for metal-gate/high-k/SiO2/Si stacked MOSFETs.

  17. Analysis of transmitting characteristics of high-transparency double-layer metallic meshes with submillimeter period using an analytical model.

    Science.gov (United States)

    Lu, Zhengang; Tan, Jiubin

    2008-10-10

    The transmitting characteristics of high-transparency double-layer metallic meshes with submillimeter period were analyzed using an analytical model, which was established using angular spectrum propagation theory and verified through experiments. It was found through analysis that rotating misalignment has significant effect on the distribution of diffraction spot intensity. Large period and small linewidth can be used to obtain high transmittance and low levels of stray light. Substrate thickness has little effect on transmitting characteristics of mesh, and so it is a variable free to choose in optimizing shielding characteristics of mesh. We think, together with other ways and means of optimizing shielding characteristics of mesh, the model can also be used for the optimization of a high-pass mesh filter.

  18. Analytical specificity and sensitivity of the novel dual-target GeneProof Neisseria gonorrhoeae PCR kit for detection of N. gonorrhoeae.

    Science.gov (United States)

    Golparian, Daniel; Hellmark, Bengt; Unemo, Magnus

    2015-11-01

    Detection of Neisseria gonorrhoeae relies increasingly on nucleic acid amplification tests (NAATs). The specificity of many gonococcal NAATs has been suboptimal and supplementary testing remains recommended in Europe and several additional countries. The novel dual-target GeneProof Neisseria gonorrhoeae PCR kit, targeting porA pseudogene and 16S rRNA gene, showed a high specificity and sensitivity when isolates of non-gonococcal Neisseria and related species (n = 144), and gonococci (n = 104) were tested. However, rare gonococcal porA mutants were only detected in the 16S rRNA gene target and two non-gonococcal isolates showed a low-level cross-reactivity in the 16S rRNA gene target. The detection limit for both targets was 1.5 copies per reaction.

  19. A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance

    Energy Technology Data Exchange (ETDEWEB)

    Wang Xianfeng; Ding Bin [State Key Laboratory for Modification of Chemical Fibers and Polymer Materials, College of Materials Science and Engineering, Donghua University, Shanghai 201620 (China); Yu Jianyong [Nanomaterials Research Center, Modern Textile Institute, Donghua University, Shanghai 200051 (China); Wang, Moran [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Pan Fukui, E-mail: binding@dhu.edu.cn [College of Textiles and Fashion, Qingdao University, Qingdao 266071 (China)

    2010-02-05

    A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log({Delta}f) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability.

  20. A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance

    Science.gov (United States)

    Wang, Xianfeng; Ding, Bin; Yu, Jianyong; Wang, Moran; Pan, Fukui

    2010-02-01

    A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log(Δf) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability.

  1. High sensitivity to mass-ratio variation in deep molecular potentials

    CERN Document Server

    Hanneke, D; Lane, D A

    2016-01-01

    Molecular vibrational transitions are prime candidates for model-independent searches for variation of the proton-to-electron mass ratio. Searches for present-day variation achieve highest sensitivity with deep molecular potentials. We identify several high-sensitivity transitions in the deeply bound ${\\rm O}_2^+$ molecular ion. These transitions are electric-dipole forbidden and thus have narrow linewidths. The most sensitive transitions take advantage of an accidental degeneracy between vibrational states in different electronic potentials. We suggest experimentally feasible routes to a measurement with uncertainty exceeding current limits on present-day variation in $m_p/m_e$.

  2. High sensitivity to variation in the proton-to-electron mass ratio in O2+

    Science.gov (United States)

    Hanneke, D.; Carollo, R. A.; Lane, D. A.

    2016-11-01

    Molecular vibrational transitions are prime candidates for model-independent searches for variation of the proton-to-electron mass ratio. Searches for present-day variation achieve the highest sensitivity with deep molecular potentials. We identify several high-sensitivity transitions in the deeply bound O2+ molecular ion. These transitions are electric-dipole forbidden and have narrow linewidths. The most sensitive transitions take advantage of an accidental degeneracy between vibrational states in different electronic potentials. We suggest experimentally feasible routes to a measurement with uncertainty below current limits on present-day variation in mp/me .

  3. Solution Process Synthesis of High Aspect Ratio ZnO Nanorods on Electrode Surface for Sensitive Electrochemical Detection of Uric Acid

    Science.gov (United States)

    Ahmad, Rafiq; Tripathy, Nirmalya; Ahn, Min-Sang; Hahn, Yoon-Bong

    2017-04-01

    This study demonstrates a highly stable, selective and sensitive uric acid (UA) biosensor based on high aspect ratio zinc oxide nanorods (ZNRs) vertical grown on electrode surface via a simple one-step low temperature solution route. Uricase enzyme was immobilized on the ZNRs followed by Nafion covering to fabricate UA sensing electrodes (Nafion/Uricase-ZNRs/Ag). The fabricated electrodes showed enhanced performance with attractive analytical response, such as a high sensitivity of 239.67 μA cm-2 mM-1 in wide-linear range (0.01-4.56 mM), rapid response time (~3 s), low detection limit (5 nM), and low value of apparent Michaelis-Menten constant (Kmapp, 0.025 mM). In addition, selectivity, reproducibility and long-term storage stability of biosensor was also demonstrated. These results can be attributed to the high aspect ratio of vertically grown ZNRs which provides high surface area leading to enhanced enzyme immobilization, high electrocatalytic activity, and direct electron transfer during electrochemical detection of UA. We expect that this biosensor platform will be advantageous to fabricate ultrasensitive, robust, low-cost sensing device for numerous analyte detection.

  4. Highly sensitive refractive index sensor based on two cascaded microfiber knots with Vernier effect

    Science.gov (United States)

    Xu, Zhilin; Sun, Qizhen; Jia, Weihua; Shum, Perry Ping; Liu, Deming

    2014-05-01

    A highly sensitive refractive index (RI) sensor based on two cascaded microfiber knots with vernier effect is proposed and demonstrated by theoretical arithmetic. Deriving from high proportional evanescent field of microfiber and sharp spectrum fringes induced by vernier effect, a slight change of ambient RI will cause large variation of effective RI and significant wavelength shift of resonant peaks, indicating high sensitivity and resolution of the proposed compound resonator. Numerical analysis demonstrates a high sensitivity of 10000nm/RIU and a resolution of 5.57×10-5 RIU at the ambient RI around 1.33 for the fiber diameter of 1μm and cavity radii of R1 = 500μm, R2 = 547.62μm

  5. Highly sensitive optical chemosensor for the detection of Cu2+ using a rhodamine B spirolatam

    Indian Academy of Sciences (India)

    Gen Hua Wu; Dong Xiang Wang; Da Yu Wu; Yuan Gao; Zhu Qing Wang

    2009-07-01

    Highly sensitive colorimetric chemosensor molecule RHN for selective detection of Cu2+ in mixed CH3CN aqueous media was designed and prepared by incorporating the well-known rhodamine fluorophore and a terdentate O2N binding unit into one molecule. The chemosensor RHN showed not only a reversible, selective, and sensitive absorbance enhancement response to Cu2+, but also a strong colour development against the colourless blank during the sensing event, a feature that would facilitate `naked-eye’ detection.

  6. Highly sensitive electromembrane extraction for the determination of volatile organic compound metabolites in dried urine spot.

    Science.gov (United States)

    Suh, Joon Hyuk; Eom, Han Young; Kim, Unyong; Kim, Junghyun; Cho, Hyun-Deok; Kang, Wonjae; Kim, Da Som; Han, Sang Beom

    2015-10-16

    Electromembrane extraction coupled with liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed for determination of ten volatile organic compound metabolites in dried urine spot samples. The dried urine spot approach is a convenient and economical sampling method, wherein urine is spotted onto a filter paper and dried. This method requires only a small amount of sample, but the analysis sometimes suffers from low sensitivity, which can lead to analytical problems in the detection of minor components in samples. The newly developed dried urine spot analysis using electromembrane extraction exhibited improved sensitivity and extraction, and enrichment of the sample was rapidly achieved in one step by applying an electric field. Aliquots of urine were spotted onto Bond Elut DMS cards and dried at room temperature. After drying, the punched out dried urine spot was eluted with water. Volatile organic compound metabolites were extracted from the sample through a supported liquid membrane into an alkaline acceptor solution inside the lumen of a hollow fiber with the help of an electric potential. The optimum extraction conditions were determined by using design of experiments (fractional factorial design and response surface methodology). Satisfactory sensitivity was achieved and the limits of quantification (LOQ) obtained were lower than the regulatory threshold limits. The method was validated by assessing the linearity, precision, accuracy, recovery, reproducibility, stability, and matrix effects. The results were acceptable, and the developed method was successfully applied to biological exposure monitoring of volatile organic compound metabolites in fifty human urine samples.

  7. Analytical evaluation on loss of off-side electric power simulation of the High Temperature Engineering Test Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Takeshi; Nakagawa, Shigeaki; Tachibana, Yukio; Takada, Eiji; Kunitomi, Kazuhiko [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment

    2000-03-01

    A rise-to-power test of the high temperature engineering test reactor (HTTR) started on September 28 in 1999 for establishing and upgrading the technological basis for the high temperature gas-cooled reactor (HTGR). A loss of off-site electric power test of the HTTR from the normal operation under 15 and 30 MW thermal power will be carried out in the rise-to-power test. Analytical evaluations on transient behaviors of the reactor and plant during the loss of off-site electric power were conducted. These estimations are proposed as benchmark problems for the IAEA coordinated research program on 'Evaluation of HTGR Performance'. This report describes an event scenario of transient during the loss of off-site electric power, the outline of major components and system, detailed thermal and nuclear data set for these problems and pre-estimation results of the benchmark problems by an analytical code 'ACCORD' for incore and plant dynamics of the HTGR. (author)

  8. Analytic calculation of two-loop QCD corrections to b → sl+l- in the high q2 region

    Science.gov (United States)

    Greub, C.; Pilipp, V.; Schüpbach, C.

    2008-12-01

    We present our results for the NNLL virtual corrections to the matrix elements of the operators O1 and O2 for the inclusive process b → sl+l- in the kinematical region q2 > 4mc2, where q2 is the invariant mass squared of the lepton-pair. This is the first analytic two-loop calculation of these matrix elements in the high q2 region. We give the matrix elements as an expansion in mc/mb and keep the full analytic dependence on q2. Making extensive use of differential equation techniques, we fully automatize the expanding of the Feynman integrals in mc/mb. In coincidence with an earlier work where the master integrals were obtained numerically [1], we find that in the high q2 region the αs corrections to the matrix elements langlesl+l-|O1,2|brangle calculated in the present paper lead to a decrease of the perturbative part of the q2-spectrum by 10%-15% relative to the NNLL result in which these contributions are put to zero and reduce the renormalization scale uncertainty to ~ 2%.

  9. Automated Sample Preparation for Radiogenic and Non-Traditional Metal Isotopes: Removing an Analytical Barrier for High Sample Throughput

    Science.gov (United States)

    Field, M. Paul; Romaniello, Stephen; Gordon, Gwyneth W.; Anbar, Ariel D.; Herrmann, Achim; Martinez-Boti, Miguel A.; Anagnostou, Eleni; Foster, Gavin L.

    2014-05-01

    MC-ICP-MS has dramatically improved the analytical throughput for high-precision radiogenic and non-traditional isotope ratio measurements, compared to TIMS. The generation of large data sets, however, remains hampered by tedious manual drip chromatography required for sample purification. A new, automated chromatography system reduces the laboratory bottle neck and expands the utility of high-precision isotope analyses in applications where large data sets are required: geochemistry, forensic anthropology, nuclear forensics, medical research and food authentication. We have developed protocols to automate ion exchange purification for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U) using the new prepFAST-MC™ (ESI, Nebraska, Omaha). The system is not only inert (all-flouropolymer flow paths), but is also very flexible and can easily facilitate different resins, samples, and reagent types. When programmed, precise and accurate user defined volumes and flow rates are implemented to automatically load samples, wash the column, condition the column and elute fractions. Unattended, the automated, low-pressure ion exchange chromatography system can process up to 60 samples overnight. Excellent reproducibility, reliability, recovery, with low blank and carry over for samples in a variety of different matrices, have been demonstrated to give accurate and precise isotopic ratios within analytical error for several isotopic systems (B, Ca, Fe, Cu, Zn, Sr, Cd, Pb and U). This illustrates the potential of the new prepFAST-MC™ (ESI, Nebraska, Omaha) as a powerful tool in radiogenic and non-traditional isotope research.

  10. Analytical Validation of a Portable Mass Spectrometer Featuring Interchangeable, Ambient Ionization Sources for High Throughput Forensic Evidence Screening

    Science.gov (United States)

    Lawton, Zachary E.; Traub, Angelica; Fatigante, William L.; Mancias, Jose; O'Leary, Adam E.; Hall, Seth E.; Wieland, Jamie R.; Oberacher, Herbert; Gizzi, Michael C.; Mulligan, Christopher C.

    2016-12-01

    Forensic evidentiary backlogs are indicative of the growing need for cost-effective, high-throughput instrumental methods. One such emerging technology that shows high promise in meeting this demand while also allowing on-site forensic investigation is portable mass spectrometric (MS) instrumentation, particularly that which enables the coupling to ambient ionization techniques. While the benefits of rapid, on-site screening of contraband can be anticipated, the inherent legal implications of field-collected data necessitates that the analytical performance of technology employed be commensurate with accepted techniques. To this end, comprehensive analytical validation studies are required before broad incorporation by forensic practitioners can be considered, and are the focus of this work. Pertinent performance characteristics such as throughput, selectivity, accuracy/precision, method robustness, and ruggedness have been investigated. Reliability in the form of false positive/negative response rates is also assessed, examining the effect of variables such as user training and experience level. To provide flexibility toward broad chemical evidence analysis, a suite of rapidly-interchangeable ion sources has been developed and characterized through the analysis of common illicit chemicals and emerging threats like substituted phenethylamines.

  11. Analytical Validation of a Portable Mass Spectrometer Featuring Interchangeable, Ambient Ionization Sources for High Throughput Forensic Evidence Screening

    Science.gov (United States)

    Lawton, Zachary E.; Traub, Angelica; Fatigante, William L.; Mancias, Jose; O'Leary, Adam E.; Hall, Seth E.; Wieland, Jamie R.; Oberacher, Herbert; Gizzi, Michael C.; Mulligan, Christopher C.

    2017-06-01

    Forensic evidentiary backlogs are indicative of the growing need for cost-effective, high-throughput instrumental methods. One such emerging technology that shows high promise in meeting this demand while also allowing on-site forensic investigation is portable mass spectrometric (MS) instrumentation, particularly that which enables the coupling to ambient ionization techniques. While the benefits of rapid, on-site screening of contraband can be anticipated, the inherent legal implications of field-collected data necessitates that the analytical performance of technology employed be commensurate with accepted techniques. To this end, comprehensive analytical validation studies are required before broad incorporation by forensic practitioners can be considered, and are the focus of this work. Pertinent performance characteristics such as throughput, selectivity, accuracy/precision, method robustness, and ruggedness have been investigated. Reliability in the form of false positive/negative response rates is also assessed, examining the effect of variables such as user training and experience level. To provide flexibility toward broad chemical evidence analysis, a suite of rapidly-interchangeable ion sources has been developed and characterized through the analysis of common illicit chemicals and emerging threats like substituted phenethylamines. [Figure not available: see fulltext.

  12. Development of a method for comprehensive and quantitative analysis of plant hormones by highly sensitive nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Izumi, Yoshihiro; Okazawa, Atsushi; Bamba, Takeshi; Kobayashi, Akio [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan); Fukusaki, Eiichiro, E-mail: fukusaki@bio.eng.osaka-u.ac.jp [Department of Biotechnology, Graduate School of Engineering, Osaka University, 2-1 Yamadaoka, Suita, Osaka 565-0871 (Japan)

    2009-08-26

    In recent plant hormone research, there is an increased demand for a highly sensitive and comprehensive analytical approach to elucidate the hormonal signaling networks, functions, and dynamics. We have demonstrated the high sensitivity of a comprehensive and quantitative analytical method developed with nanoflow liquid chromatography-electrospray ionization-ion trap mass spectrometry (LC-ESI-IT-MS/MS) under multiple-reaction monitoring (MRM) in plant hormone profiling. Unlabeled and deuterium-labeled isotopomers of four classes of plant hormones and their derivatives, auxins, cytokinins (CK), abscisic acid (ABA), and gibberellins (GA), were analyzed by this method. The optimized nanoflow-LC-ESI-IT-MS/MS method showed ca. 5-10-fold greater sensitivity than capillary-LC-ESI-IT-MS/MS, and the detection limits (S/N = 3) of several plant hormones were in the sub-fmol range. The results showed excellent linearity (R{sup 2} values of 0.9937-1.0000) and reproducibility of elution times (relative standard deviations, RSDs, <1.1%) and peak areas (RSDs, <10.7%) for all target compounds. Further, sample purification using Oasis HLB and Oasis MCX cartridges significantly decreased the ion-suppressing effects of biological matrix as compared to the purification using only Oasis HLB cartridge. The optimized nanoflow-LC-ESI-IT-MS/MS method was successfully used to analyze endogenous plant hormones in Arabidopsis and tobacco samples. The samples used in this analysis were extracted from only 17 tobacco dry seeds (1 mg DW), indicating that the efficiency of analysis of endogenous plant hormones strongly depends on the detection sensitivity of the method. Our analytical approach will be useful for in-depth studies on complex plant hormonal metabolism.

  13. A novel detection platform for parallel monitoring of DNA hybridization with high sensitivity and specificity

    DEFF Research Database (Denmark)

    Yi, Sun; Perch-Nielsen, Ivan R.; Wang, Zhenyu;

    We developed a high-sensitive platform to monior multiple hybridization events in real time. By creating a microoptical array in a polymeric chip, the system combine the excellent discriminative power of supercritical angle fluorescence (SAF) microscopy with high-throughput capabilities...

  14. An analytical method for determination of fullerenes and functionalized fullerenes in soils with high performance liquid chromatography and UV detection

    Energy Technology Data Exchange (ETDEWEB)

    Carboni, Andrea, E-mail: A.carboni@uva.nl [University of Amsterdam - IBED, Sciencepark 904, 1098 XH Amsterdam (Netherlands); Emke, Erik [KWR, Watercycle Research Institute, P.O. Box 1072, 3433 PE Nieuwegein (Netherlands); Parsons, John R.; Kalbitz, Karsten [University of Amsterdam - IBED, Sciencepark 904, 1098 XH Amsterdam (Netherlands); Voogt, Pim de [University of Amsterdam - IBED, Sciencepark 904, 1098 XH Amsterdam (Netherlands); KWR, Watercycle Research Institute, P.O. Box 1072, 3433 PE Nieuwegein (Netherlands)

    2014-01-07

    Graphical abstract: -- Highlights: •A total of eight fullerenes can be analyzed in a single run with HPLC-UV. •The method allows the analysis of fullerenes in soil at relatively low concentrations. •The method developed is robust, highly reproducible and relatively efficient. •The method can be applied to the study of the environmental fate and toxicology of fullerenes. -- Abstract: Fullerenes are carbon-based nanomaterials expected to play a major role in emerging nanotechnology and produced at an increasing rate for industrial and household applications. In the last decade a number of novel compounds (i.e. fullerene derivatives) is being introduced into the market and specific analytical methods are needed for analytical purposes as well as environmental and safety issues. In the present work eight fullerenes (C60 and C70) and functionalized fullerenes (C60 and C70 exohedral-derivatives) were selected and a novel liquid chromatographic method was developed for their analysis with UV absorption as a method of detection. The resulting HPLC-UV method is the first one suitable for the analysis of all eight compounds. This method was applied for the analysis of fullerenes added to clayish, sandy and loess top-soils at concentrations of 20, 10 and 5 μg kg{sup −1} and extracted with a combination of sonication and shaking extraction. The analytical method limits of detection (LoD) and limits of quantification (LoQ) were in the range of 6–10 μg L{sup −1} and 15–24 μg L{sup −1} respectively for the analytical solutions. The extraction from soil was highly reproducible with recoveries ranging from 47 ± 5 to 71 ± 4% whereas LoD and LoQ for all soils tested were of 3 μg kg{sup −1} and 10 μg kg{sup −1} respectively. No significant difference in the extraction performance was observed depending of the different soil matrices and between the different concentrations. The developed method can be applied for the study of the fate and toxicity of

  15. A Validated High-Throughput Fluorometric Method for Determination of Omeprazole in Quality Control Laboratory via Charge Transfer Sensitized Fluorescence.

    Science.gov (United States)

    Mahmoud, Ashraf M; Ahmed, Sameh A

    2016-03-01

    A high-throughput 96-microwell plate fluorometric method was developed and validated to determine omeprazole (OMZ) in its dosage forms. The method was based on the charge-transfer (CT) sensitized fluorescence reaction of OMZ with 2, 3-dichloro-5, 6-dicyano-1, 4-benzoquinone (DDQ). This fluorescence reaction provided a new approach for simple, sensitive and selective determinations of OMZ in pharmaceutical preparations. In the present method, the fluorescence reaction was carried out in 96-microwell plates as reaction vessels in order to increase the automation of the methodology and the efficiency of its use in quality control laboratories. All factors affecting the fluorescence reaction were carefully studied and the conditions were optimized. The stoichiometry of the fluorescence reaction between OMZ and DDQ was determined and the reaction mechanism was suggested. Under the optimum conditions, the linear range was 100-6000 ng/ml with the lowest LOD of 33 ng/ml. Analytical performance of the proposed assay, in terms of accuracy and precision, was statistically validated and the results were satisfactory; RSD was <2.6 % and the accuracy was 98.6-101.6 %. The method was successfully applied to the analysis of OMZ in its dosage forms; the recovery values were 98.26-99.60 ± 0.95-2.22 %. The developed methodology may provide a safer, automated and economic tool for the analysis of OMZ in quality control laboratories.

  16. High-sensitivity MALDI-TOF MS quantification of anthrax lethal toxin for diagnostics and evaluation of medical countermeasures.

    Science.gov (United States)

    Boyer, Anne E; Gallegos-Candela, Maribel; Quinn, Conrad P; Woolfitt, Adrian R; Brumlow, Judith O; Isbell, Katherine; Hoffmaster, Alex R; Lins, Renato C; Barr, John R

    2015-04-01

    Inhalation anthrax has a rapid progression and high fatality rate. Pathology and death from inhalation of Bacillus anthracis spores are attributed to the actions of secreted protein toxins. Protective antigen (PA) binds and imports the catalytic component lethal factor (LF), a zinc endoprotease, and edema factor (EF), an adenylyl cyclase, into susceptible cells. PA-LF is termed lethal toxin (LTx) and PA-EF, edema toxin. As the universal transporter for both toxins, PA is an important target for vaccination and immunotherapeutic intervention. However, its quantification has been limited to methods of relatively low analytic sensitivity. Quantification of LTx may be more clinically relevant than LF or PA alone because LTx is the toxic form that acts on cells. A method was developed for LTx-specific quantification in plasma using anti-PA IgG magnetic immunoprecipitation of PA and quantification of LF activity that co-purified with PA. The method was fast (anthrax and as long as 8 days post-treatment. Over the course of infection in two rhesus macaques, LTx was first detected at 0.101 and 0.237 ng/mL at 36 h post-exposure and increased to 1147 and 12,107 ng/mL in late-stage anthrax. This demonstrated the importance of LTx as a diagnostic and therapeutic target. This method provides a sensitive, accurate tool for anthrax toxin detection and evaluation of PA-directed therapeutics.

  17. Development of highly sensitive and selective antibodies for the detection of the explosive pentaerythritol tetranitrate (PETN) by bioisosteric replacement.

    Science.gov (United States)

    Hesse, Almut; Biyikal, Mustafa; Rurack, Knut; Weller, Michael G

    2016-02-01

    An improved antibody against the explosive pentaerythritol tetranitrate (PETN) was developed. The immunogen was designed by the concept of bioisosteric replacement, which led to an excellent polyclonal antibody with extreme selectivity and immunoassays of very good sensitivity. Compounds such as nitroglycerine, 2,4,6-trinitrotoluene, 1,3,5-trinitrobenzene, hexogen (RDX), 2,4,6-trinitroaniline, 1,3-dinitrobenzene, octogen (HMX), triacetone triperoxide, ammonium nitrate, 2,4,6-trinitrophenol and nitrobenzene were tested for potential cross-reactivity. The detection limit of a competitive enzyme-linked immunosorbent assay was determined to be around 0.5 µg/l. The dynamic range of the assay was found to be between 1 and 1000 µg/l, covering a concentration range of three decades. This work shows the successful application of the bioisosteric concept in immunochemistry by exchange of a nitroester to a carbonate diester. The antiserum might be used for the development of quick tests, biosensors, microtitration plate immunoassays, microarrays and other analytical methods for the highly sensitive detection of PETN, an explosive frequently used by terrorists, exploiting the extreme difficulty of its detection. Copyright © 2015 John Wiley & Sons, Ltd.

  18. A versatile quantitation platform based on platinum nanoparticles incorporated volumetric bar-chart chip for highly sensitive assays.

    Science.gov (United States)

    Wang, Yuzhen; Zhu, Guixian; Qi, Wenjin; Li, Ying; Song, Yujun

    2016-11-15

    Platinum nanoparticles incorporated volumetric bar-chart chip (PtNPs-V-Chip) is able to be used for point-of-care tests by providing quantitative and visualized readout without any assistance from instruments, data processing, or graphic plotting. To improve the sensitivity of PtNPs-V-Chip, hybridization chain reaction was employed in this quantitation platform for highly sensitive assays that can detect as low as 16 pM Ebola Virus DNA, 0.01ng/mL carcinoembryonic antigen (CEA), and the 10 HER2-expressing cancer cells. Based on this amplified strategy, a 100-fold decrease of detection limit was achieved for DNA by improving the number of platinum nanoparticle catalyst for the captured analyte. This quantitation platform can also distinguish single base mismatch of DNA hybridization and observe the concentration threshold of CEA. The new strategy lays the foundation for this quantitation platform to be applied in forensic analysis, biothreat detection, clinical diagnostics and drug screening.

  19. New approaches to donor crossmatching and successful transplantation of highly sensitized patients.

    Science.gov (United States)

    Delmonico, F L; Fuller, A; Cosimi, A B; Tolkoff-Rubin, N; Russell, P S; Rodey, G E; Fuller, T C

    1983-12-01

    A class I HLA molecule may bear not only a private or unique determinant, but a shared, yet discrete, public epitope. These public determinants occur with a much higher frequency in the random donor population than the associated private determinants--and thus, are encountered more often in random donor blood transfusions and in renal transplantation. Sera from highly sensitized dialysis patients have been reported to contain a restricted number of antibodies to public determinants rather than a diverse array of antibodies directed against the private HLA-AB epitopes. As detailed in this report, comprehensive serum analysis of the public antibodies in highly sensitized transplant candidates has optimized identification of potential crossmatch-compatible donors and has avoided needless crossmatches. During the past two years, the incidence of renal transplantation from cadaveric donors to highly sensitized recipients has doubled at this institution. At 10-25 months following transplantation, 70% of these allografts are functioning. Private HLA class I antigen incompatibility was not a barometer for exclusion in the final donor crossmatch of these highly sensitized recipients. Furthermore, positive donor T cell crossmatches with sera obtained more than six months prior to transplantation may not represent an impediment to successful transplantation. We conclude that the approach of detailed antibody analysis can result in an improved outlook for successful transplantation of more dialysis patients who are highly sensitized to the class I HLA alloantigens.

  20. Evaluation of a High-Sensitivity GPS Receiver for Kinematics Application in Regions with High Shading

    Science.gov (United States)

    Suhandri, H. F.; Becker, D.; Kleusberg, A.

    2009-04-01

    GPS positioning has been very much improved with high-sensitivity GPS (HSGPS) receivers. This kind of receiver can track the signal until 20-25dB below the level of conventional receivers. Obviously, no problem occurs when GPS technology is used for air and ocean vehicles navigation; sufficient and/or redundant signals can be easily acquired due to good hemispherical signal reception. A problem arises whenever signals cannot be traced anymore, if not enough satellites are available or if there is very weak signal reception in forest areas or between buildings. Those situations cannot be avoided or eliminated in land vehicle navigation. The HSGPS technology tries to solve those problems by tracking signals below the normal signal threshold of non-HSGPS receivers. This paper discusses the two factors of availability and accuracy in the context of navigation with HSGPS receivers. In order to investigate these issues some scenarios of receivers-placing will be examined which represent various receiver environments: good hemispherical signal reception, strong signal shading environment and indoor environment. The signal availability and accuracy are investigated during observation sessions of several hours by comparing the measurements of the HSGPS receiver with the measurements of a conventional, non-HSGPS receiver. As expected, the non-HSGPS receiver yields the same level of availability as the HSGPS receiver in an environment with good hemispherical signal reception. When both receivers are located in an environment with significant signal shading, the percentage of availability will significantly decay for the non-HSGPS receiver whereas the availability of the HSGPS receiver is much less reduced. However the results from the HSGPS receiver in this case are at a significantly reduced accuracy level. The accuracy level is assessed by using three parameters: i) the difference between the C/A code and the carrier phase in order to investigate how big the multipath and

  1. Ultra high vacuum pumping system and high sensitivity helium leak detector

    Science.gov (United States)

    Myneni, Ganapati Rao

    1997-01-01

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

  2. A Concept of Constructing a Common Information Space for High Tech Programs Using Information Analytical Systems

    Science.gov (United States)

    Zakharova, Alexandra A.; Kolegova, Olga A.; Nekrasova, Maria E.

    2016-04-01

    The paper deals with the issues in program management used for engineering innovative products. The existing project management tools were analyzed. The aim is to develop a decision support system that takes into account the features of program management used for high-tech products: research intensity, a high level of technical risks, unpredictable results due to the impact of various external factors, availability of several implementing agencies. The need for involving experts and using intelligent techniques for information processing is demonstrated. A conceptual model of common information space to support communication between members of the collaboration on high-tech programs has been developed. The structure and objectives of the information analysis system “Geokhod” were formulated with the purpose to implement the conceptual model of common information space in the program “Development and production of new class mining equipment - “Geokhod”.

  3. Highly sensitive ion-sensitive field-effect transistor sensor using fully transparent amorphous In–Ga–Zn–O thin-film transistors

    Science.gov (United States)

    Ahn, Min-Ju; Lim, Cheol-Min; Cho, Won-Ju

    2017-03-01

    In this study, a highly sensitive ion-sensitive field-effect transistor (ISFET) sensor was developed using fully transparent amorphous In–Ga–Zn–O thin-film transistors fabricated on a glass substrate. To overcome the issues associated with conventional ISFETs, such as low sensitivity and poor reliability, a dual-gate (DG) operating mode was employed, which is able to significantly amplify the sensitivity through capacitive coupling between the front and back gate dielectrics. As a result, when compared to the sensitivity in the single-gate mode, the DG mode exhibited a high sensitivity of 269.3 mV/pH, which is beyond the Nernst response limit.

  4. High sensitivity detection and characterization of the chemical state of trace element contamination on silicon wafers

    CERN Document Server

    Pianetta, Piero A; Baur, K; Brennan, S; Homma, T; Kubo, N

    2003-01-01

    Increasing the speed and complexity of semiconductor integrated circuits requires advanced processes that put extreme constraints on the level of metal contamination allowed on the surfaces of silicon wafers. Such contamination degrades the performance of the ultrathin SiO sub 2 gate dielectrics that form the heart of the individual transistors. Ultimately, reliability and yield are reduced to levels that must be improved before new processes can be put into production. It should be noted that much of this metal contamination occurs during the wet chemical etching and rinsing steps required for the manufacture of integrated circuits and industry is actively developing new processes that have already brought the metal contamination to levels beyond the measurement capabilities of conventional analytical techniques. The measurement of these extremely low contamination levels has required the use of synchrotron radiation total reflection X-ray fluorescence (SR-TXRF) where sensitivities 100 times better than conv...

  5. New high temperature plasmas and sample introduction systems for analytical atomic emission and mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Montaser, A.

    1992-01-01

    New high temperature plasmas and new sample introduction systems are explored for rapid elemental and isotopic analysis of gases, solutions, and solids using mass spectrometry and atomic emission spectrometry. Emphasis was placed on atmospheric pressure He inductively coupled plasmas (ICP) suitable for atomization, excitation, and ionization of elements; simulation and computer modeling of plasma sources with potential for use in spectrochemical analysis; spectroscopic imaging and diagnostic studies of high temperature plasmas, particularly He ICP discharges; and development of new, low-cost sample introduction systems, and examination of techniques for probing the aerosols over a wide range. Refs., 14 figs. (DLC)

  6. The Design and Optimization of a Highly Sensitive and Overload-Resistant Piezoresistive Pressure Sensor

    Directory of Open Access Journals (Sweden)

    Xiawei Meng

    2016-03-01

    Full Text Available A piezoresistive pressure sensor with a beam-membrane-dual-island structure is developed for micro-pressure monitoring in the field of aviation, which requires great sensitivity and overload resistance capacity. The design, fabrication, and test of the sensor are presented in this paper. By analyzing the stress distribution of sensitive elements using the finite element method, a novel structure incorporating sensitive beams with a traditional bossed diaphragm is built up. The proposed structure proved to be advantageous in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the sensor equations. Fabricated on an n-type single crystal silicon wafer, the sensor chips are wire-bonded to a printed circuit board (PCB and packaged for experiments. The static and dynamic characteristics are tested and discussed. Experimental results show that the sensor has a sensitivity as high as 17.339 μV/V/Pa in the range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure. Due to the excellent performance, the sensor can be applied in measuring micro-pressure lower than 500 Pa.

  7. Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon

    Institute of Scientific and Technical Information of China (English)

    Fang Yun-Zhang; Xu Qi-Ming; Zheng Jin-Ju; Wu Feng-Min; Ye Hui-Qun; Si Jian-Xiao; Zheng Jian-Long; Fan Xiao-Zhen; Yang Xiao-Hong

    2012-01-01

    The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.sB19.2 (FeCo-based) ribbon under a weak magnetic field (WMF) is presented in this paper. The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitrogen atmosphere.The giant magnetoimpedance effect in solenoid (GMIES) profiles are measured with an HP4294A impedance analyzer.The result shows that the GMIES responds to the WMF sensitively (as high as 1580 %/A·m-l).The high sensitivity can be obtained in a moderate narrow range of annealing current density (30-34 A/mm2) and closely depends on the driven current frequency.The highest sensitivity (1580 %/A.m-1) is obtained when the FeCobased amorphous ribbon is annealed at 32 A/mm2 for 10 min and then driven with an alterning current (AC) at the frequency of 350 kHz.The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure,which is induced by the temperature gradient produced during Joule-heating the ribbon.

  8. High degree gravitational sensitivity from Mars orbiters for the GMM-1 gravity model

    Science.gov (United States)

    Lerch, F. J.; Smith, D. E.; Chan, J. C.; Patel, G. B.; Chinn, D. S.

    1994-01-01

    Orbital sensitivity of the gravity field for high degree terms (greater than 30) is analyzed on satellites employed in a Goddard Mars Model GMM-1, complete in spherical harmonics through degree and order 50. The model is obtained from S-band Doppler data on Mariner 9 (M9), Viking Orbiter 1 (VO1), and Viking Orbiter 2 (VO2) spacecraft, which were tracked by the NASA Deep Space Network on seven different highly eccentric orbits. The main sensitivity of the high degree terms is obtained from the VO1 and VO2 low orbits (300 km periapsis altitude), where significant spectral sensitivity is seen for all degrees out through degree 50. The velocity perturbations show a dominant effect at periapsis and significant effects out beyond the semi-latus rectum covering over 180 degrees of the orbital groundtrack for the low altitude orbits. Because of the wideband of periapsis motion covering nearly 180 degrees in w and +39 degrees in latitude coverage, the VO1 300 km periapsis altitude orbit with inclination of 39 degrees gave the dominant sensitivity in the GMM-1 solution for the high degree terms. Although the VO2 low periapsis orbit has a smaller band of periapsis mapping coverage, it strongly complements the VO1 orbit sensitivity for the GMM-1 solution with Doppler tracking coverage over a different inclination of 80 degrees.

  9. The Design and Optimization of a Highly Sensitive and Overload-Resistant Piezoresistive Pressure Sensor.

    Science.gov (United States)

    Meng, Xiawei; Zhao, Yulong

    2016-03-09

    A piezoresistive pressure sensor with a beam-membrane-dual-island structure is developed for micro-pressure monitoring in the field of aviation, which requires great sensitivity and overload resistance capacity. The design, fabrication, and test of the sensor are presented in this paper. By analyzing the stress distribution of sensitive elements using the finite element method, a novel structure incorporating sensitive beams with a traditional bossed diaphragm is built up. The proposed structure proved to be advantageous in terms of high sensitivity and high overload resistance compared with the conventional bossed diaphragm and flat diaphragm structures. Curve fittings of surface stress and deflection based on ANSYS simulation results are performed to establish the sensor equations. Fabricated on an n-type single crystal silicon wafer, the sensor chips are wire-bonded to a printed circuit board (PCB) and packaged for experiments. The static and dynamic characteristics are tested and discussed. Experimental results show that the sensor has a sensitivity as high as 17.339 μV/V/Pa in the range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure. Due to the excellent performance, the sensor can be applied in measuring micro-pressure lower than 500 Pa.

  10. The Sensitivity of Adolescent School-Based Hearing Screens Is Significantly Improved by Adding High Frequencies.

    Science.gov (United States)

    Sekhar, Deepa L; Zalewski, Thomas R; Beiler, Jessica S; Czarnecki, Beth; Barr, Ashley L; King, Tonya S; Paul, Ian M

    2016-12-01

    High frequency hearing loss (HFHL), often related to hazardous noise, affects one in six U.S. adolescents. Yet, only 20 states include school-based hearing screens for adolescents. Only six states test multiple high frequencies. Study objectives were to (1) compare the sensitivity of state school-based hearing screens for adolescents to gold standard sound-treated booth testing and (2) consider the effect of adding multiple high frequencies and two-step screening on sensitivity/specificity. Of 134 eleventh-grade participants (2013-2014), 43 of the 134 (32%) did not pass sound-treated booth testing, and 27 of the 43 (63%) had HFHL. Sensitivity/specificity of the most common protocol (1,000, 2,000, 4,000 Hz at 20 dB HL) for these hearing losses was 25.6% (95% confidence interval [CI] = [13.5, 41.2]) and 85.7% (95% CI [76.8, 92.2]), respectively. A protocol including 500, 1,000, 2,000, 4,000, 6,000 Hz at 20 dB HL significantly improved sensitivity to 76.7% (95% CI [61.4, 88.2]), p < .001. Two-step screening maintained specificity (84.6%, 95% CI [75.5, 91.3]). Adolescent school-based hearing screen sensitivity improves with high frequencies.

  11. A Highly Sensitive CMOS Digital Hall Sensor for Low Magnetic Field Applications

    Directory of Open Access Journals (Sweden)

    Li Li

    2012-02-01

    Full Text Available Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 μm high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ±2 mT magnetic field and output a digital Hall signal in a wide temperature range from −40 °C to 120 °C.

  12. A Highly Sensitive CMOS Digital Hall Sensor for Low Magnetic Field Applications

    Science.gov (United States)

    Xu, Yue; Pan, Hong-Bin; He, Shu-Zhuan; Li, Li

    2012-01-01

    Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 μm high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ±2 mT magnetic field and output a digital Hall signal in a wide temperature range from −40 °C to 120 °C. PMID:22438758

  13. Photon Counting System for High-Sensitivity Detection of Bioluminescence at Optical Fiber End.

    Science.gov (United States)

    Iinuma, Masataka; Kadoya, Yutaka; Kuroda, Akio

    2016-01-01

    The technique of photon counting is widely used for various fields and also applicable to a high-sensitivity detection of luminescence. Thanks to recent development of single photon detectors with avalanche photodiodes (APDs), the photon counting system with an optical fiber has become powerful for a detection of bioluminescence at an optical fiber end, because it allows us to fully use the merits of compactness, simple operation, highly quantum efficiency of the APD detectors. This optical fiber-based system also has a possibility of improving the sensitivity to a local detection of Adenosine triphosphate (ATP) by high-sensitivity detection of the bioluminescence. In this chapter, we are introducing a basic concept of the optical fiber-based system and explaining how to construct and use this system.

  14. Fabrication of a highly sensitive penicillin sensor based on charge transfer techniques.

    Science.gov (United States)

    Lee, Seung-Ro; Rahman, M M; Sawada, Kazuaki; Ishida, Makoto

    2009-03-15

    A highly sensitive penicillin biosensor based on a charge-transfer technique (CTTPS) has been fabricated and demonstrated in this paper. CTTPS comprised a charge accumulation technique for penicilloic acid and H(+) ions perception system. With the proposed CTTPS, it is possible to amplify the sensing signals without external amplifier by using the charge accumulation cycles. The fabricated CTTPS exhibits excellent performance for penicillin detection and exhibit a high-sensitivity (47.852 mV/mM), high signal-to-noise ratio (SNR), large span (1445 mV), wide linear range (0-25 mM), fast response time (penicillin sensor and exhibited almost eight times greater sensitivity as compared to ISFET (6.56 mV/mM). The sensor system is implemented for the measurement of the penicillin concentration in penicillin fermentation broth.

  15. Repeated high-intensity exercise modulates Ca(2+) sensitivity of human skeletal muscle fibers

    DEFF Research Database (Denmark)

    Gejl, K D; Hvid, L G; Willis, S J;

    2016-01-01

    The effects of short-term high-intensity exercise on single fiber contractile function in humans are unknown. Therefore, the purposes of this study were: (a) to access the acute effects of repeated high-intensity exercise on human single muscle fiber contractile function; and (b) to examine whether...... the fourth sprint with respect to Ca(2+) sensitivity and maximal Ca(2+) -activated force. To investigate the oxidative effects of exercise on single fiber contractile function, a subset of fibers was incubated with dithiothreitol (DTT) before analysis. Ca(2+) sensitivity was enhanced by exercise in both MHC...... I (17%, P exercise. In conclusion, repeated high-intensity exercise increased Ca(2+) sensitivity in both MHC I and MHC II...

  16. Design and Synthesis of an MOF Thermometer with High Sensitivity in the Physiological Temperature Range.

    Science.gov (United States)

    Zhao, Dian; Rao, Xingtang; Yu, Jiancan; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2015-12-07

    An important result of research on mixed-lanthanide metal-organic frameworks (M'LnMOFs) is the realization of highly sensitive ratiometric luminescent thermometers. Here, we report the design and synthesis of the new M'LnMOF Tb0.80Eu0.20BPDA with high relative sensitivity in the physiological temperature regime (298-318 K). The emission intensity and luminescence lifetime were investigated and compared to those of existing materials. It was found that the temperature-dependent luminescence properties of Tb0.80Eu0.20BPDA are strongly associated with the distribution of the energy levels of the ligand. Such a property can be useful in the design of highly sensitive M'LnMOF thermometers.

  17. Optical transitions in highly charged californium ions with high sensitivity to variation of the fine-structure constant.

    Science.gov (United States)

    Berengut, J C; Dzuba, V A; Flambaum, V V; Ong, A

    2012-08-17

    We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, α. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf(16+) is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf(16+) has very large nuclear charge and large ionization energy, resulting in the largest α sensitivity seen in atomic systems. The lines include positive and negative shifters.

  18. In vivo emergence of HIV-1 highly sensitive to neutralizing antibodies.

    Directory of Open Access Journals (Sweden)

    Marlén M I Aasa-Chapman

    Full Text Available BACKGROUND: The rapid and continual viral escape from neutralizing antibodies is well documented in HIV-1 infection. Here we report in vivo emergence of viruses with heightened sensitivity to neutralizing antibodies, sometimes paralleling the development of neutralization escape. METHODOLOGY/PRINCIPAL FINDINGS: Sequential viral envs were amplified from seven HIV-1 infected men monitored from seroconversion up to 5 years after infection. Env-recombinant infectious molecular clones were generated and tested for coreceptor use, macrophage tropism and neutralization sensitivity to homologous and heterologous serum, soluble CD4 and monoclonal antibodies IgG1b12, 2G12 and 17b. We found that HIV-1 evolves sensitivity to contemporaneous neutralizing antibodies during infection. Neutralization sensitive viruses grow out even when potent autologous neutralizing antibodies are present in patient serum. Increased sensitivity to neutralization was associated with susceptibility of the CD4 binding site or epitopes induced after CD4 binding, and mediated by complex envelope determinants including V3 and V4 residues. The development of neutralization sensitive viruses occurred without clinical progression, coreceptor switch or change in tropism for primary macrophages. CONCLUSIONS: We propose that an interplay of selective forces for greater virus replication efficiency without the need to resist neutralizing antibodies in a compartment protected from immune surveillance may explain the temporal course described here for the in vivo emergence of HIV-1 isolates with high sensitivity to neutralizing antibodies.

  19. Highly-sensitive electrochemical immunosensing method based on dual amplification systems.

    Science.gov (United States)

    Yasukawa, Tomoyuki; Yoshimoto, Yoshimi; Goto, Takuya; Mizutani, Fumio

    2012-01-01

    In this work, a novel immunosensing method has been developed on the basis of the sensitive determination of a product generated by an enzyme reaction with dual amplification system combining an electrochemical-redox cycling and coulometric signal transduction using a galvanic cell. Analytes were captured on microparticles to form sandwich-type immunocomplexes and then labeled with β-galactosidase (β-gal). 4-Aminophenol (PAP) produced by enzyme reaction of β-gal was introduced into the anode compartment consisting of a comb type of an interdigitated array (IDA) electrode. PAP was oxidized at the IDA electrode by the coupled reduction of silver ions at the glassy carbon (GC) electrode of the cathode, resulting in the deposition of silver metal on the GC electrode. The other comb of the IDA electrode was used to reduce quinoneimine generated by the oxidation of PAP, regenerating PAP. The deposited silver was collectively converted to a signal by anodic stripping voltammetry. The amount of silver deposited corresponded to the degree of PAP oxidation by redox cycling, which leads to an enhancement of the stripping signal due to the conversion of the product (PAP) and accumulation of the insoluble silver metal. Using carcinoembryonic antigen as a model analyte, the present immunosensing method showed linear behavior over two orders of magnitude with detection limits down to 0.01 ng/mL. Dual signal amplification with redox cycling and coulometric signal transduction provides a promising, sensitive, and simple method for the determination of marker proteins. Copyright © 2012 Elsevier B.V. All rights reserved.

  20. Highly Sensitive and Selective Ethanol Sensor Fabricated with In-Doped 3DOM ZnO.

    Science.gov (United States)

    Wang, Zhihua; Tian, Ziwei; Han, Dongmei; Gu, Fubo

    2016-03-02

    ZnO is an important n-type semiconductor sensing material. Currently, much attention has been attracted to finding an effective method to prepare ZnO nanomaterials with high sensing sensitivity and excellent selectivity. A three-dimensionally ordered macroporous (3DOM) ZnO nanostructure with a large surface area is beneficial to gas and electron transfer, which can enhance the gas sensitivity of ZnO. Indium (In) doping is an effective way to improve the sensing properties of ZnO. In this paper, In-doped 3DOM ZnO with enhanced sensitivity and selectivity has been synthesized by using a colloidal crystal templating method. The 3DOM ZnO with 5 at. % of In-doping exhibits the highest sensitivity (∼88) to 100 ppm ethanol at 250 °C, which is approximately 3 times higher than that of pure 3DOM ZnO. The huge improvement to the sensitivity to ethanol was attributed to the increase in the surface area and the electron carrier concentration. The doping by In introduces more electrons into the matrix, which is helpful for increasing the amount of adsorbed oxygen, leading to high sensitivity. The In-doped 3DOM ZnO is a promising material for a new type of ethanol sensor.