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1

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

PubMed Central

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. PMID:23173950

2012-01-01

2

A dual role of boronate affinity in high-sensitivity detection of vicinal diol brassinosteroids from sub-gram plant tissues via UPLC-MS/MS.  

PubMed

Based on the dual role of specific boronate affinity, making use of both novel self-synthesized boronate affinity-functionalized magnetic nanoparticles and a high-efficiency organic boronic acid-type derivatization reagent, we report a simple, convenient and highly-sensitive method for detection of endogenous brassinosteroids from real plant materials. PMID:23340859

Xin, Peiyong; Yan, Jijun; Fan, Jinshi; Chu, Jinfang; Yan, Cunyu

2013-03-01

3

Novel generic UPLC\\/MS\\/MS method for high throughput analysis applied to permeability assessment in early Drug Discovery  

Microsoft Academic Search

A novel generic ultra performance liquid chromatography-tandem mass spectrometric (UPLC\\/MS\\/MS) method for the high throughput quantification of samples generated during permeability assessment (PAMPA) has been developed and validated. The novel UPLC\\/MS\\/MS methodology consists of two stages. Firstly, running a 1.5min isocratic method, compound-specific multiple reaction monitoring (MRM) methods were automatically prepared. In a second stage, samples were analyzed by a

Jurgen Mensch; Mark Noppe; Jef Adriaensen; Anouche Melis; Claire Mackie; Patrick Augustijns; Marcus E Brewster

2007-01-01

4

High-throughput quantitation of amino acids in rat and mouse biological matrices using stable isotope labeling and UPLC-MS/MS analysis.  

PubMed

Quantifying amino acids in biological matrices is typically performed using liquid chromatography (LC) coupled with fluorescent detection (FLD), requiring both derivatization and complete baseline separation of all amino acids. Due to its high specificity and sensitivity, the use of UPLC-MS/MS eliminates the derivatization step and allows for overlapping amino acid retention times thereby shortening the analysis time. Furthermore, combining UPLC-MS/MS with stable isotope labeling (e.g., isobaric tag for relative and absolute quantitation, i.e., iTRAQ) of amino acids enables quantitation while maintaining sensitivity, selectivity and speed of analysis. In this study, we report combining UPLC-MS/MS analysis with iTRAQ labeling of amino acids resulting in the elution and quantitation of 44 amino acids within 5 min demonstrating the speed and convenience of this assay over established approaches. This chromatographic analysis time represented a 5-fold improvement over the conventional HPLC-MS/MS method developed in our laboratory. In addition, the UPLC-MS/MS method demonstrated improvements in both specificity and sensitivity without loss of precision. In comparing UPLC-MS/MS and HPLC-MS/MS results of 32 detected amino acids, only 2 amino acids exhibited imprecision (RSD) >15% using UPLC-MS/MS, while 9 amino acids exhibited RSD >15% using HPLC-MS/MS. Evaluating intra- and inter-assay precision over 3 days, the quantitation range for 32 detected amino acids in rat plasma was 0.90-497 ?M, with overall mean intra-day precision of less than 15% and mean inter-day precision of 12%. This UPLC-MS/MS assay was successfully implemented for the quantitative analysis of amino acids in rat and mouse plasma, along with mouse urine and tissue samples, resulting in the following concentration ranges: 0.98-431 ?M in mouse plasma for 32 detected amino acids; 0.62-443 ?M in rat plasma for 32 detected amino acids; 0.44-8590?M in mouse liver for 33 detected amino acids; 0.61-1241 ?M in mouse kidney for 37 detected amino acids; and 1.39-1,681 ?M in rat urine for 34 detected amino acids. The utility of the assay was further demonstrated by measuring and comparing plasma amino acid levels between pre-diabetic Zucker diabetic fatty rats (ZDF/Gmi fa/fa) and their lean littermates (ZDF/Gmi fa/?). Significant differences (P<0.001) in 9 amino acid concentrations were observed, with the majority ranging from a 2- to 5-fold increase in pre-diabetic ZDF rats on comparison with ZDF lean rats, consistent with previous literature reports. PMID:24842860

Takach, Edward; O'Shea, Thomas; Liu, Hanlan

2014-08-01

5

Novel generic UPLC/MS/MS method for high throughput analysis applied to permeability assessment in early Drug Discovery.  

PubMed

A novel generic ultra performance liquid chromatography-tandem mass spectrometric (UPLC/MS/MS) method for the high throughput quantification of samples generated during permeability assessment (PAMPA) has been developed and validated. The novel UPLC/MS/MS methodology consists of two stages. Firstly, running a 1.5min isocratic method, compound-specific multiple reaction monitoring (MRM) methods were automatically prepared. In a second stage, samples were analyzed by a 1.5min generic gradient UPLC method on a BEH C18 column (50mmx2.1mm). Compounds were detected with a Waters Micromass Quattro Premier mass spectrometer operating in positive electrospray ionization using the compound-specific MRM methods. The linearity for the validation compounds (caffeine, propranolol, ampicillin, atenolol, griseofulvin and carbamazepine) typically ranges from 3.05nM to 12,500nM and the limits of detection for all generically developed methods are in the range between 0.61nM and 12nM in an aqueous buffer. The novel generic methodology was successfully introduced within early Drug Discovery and resulted in a four-fold increase of throughput as well as a significant increase in sensitivity compared to other in-house generic LC/MS methods. PMID:17095304

Mensch, Jurgen; Noppe, Mark; Adriaensen, Jef; Melis, Anouche; Mackie, Claire; Augustijns, Patrick; Brewster, Marcus E

2007-03-01

6

Rapid and sensitive UPLC-MS/MS method for the determination of domperidone in human plasma and its application to pharmacokinetic study.  

PubMed

In this study, a simple, rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method is described for determination of domperidone in human plasma samples using oxcarbazepine as the internal standard (IS). Sample preparation was accomplished through protein precipitation with methanol, and chromatographic separation was performed on an Acquity BEH C18 column (2.1?mm50?mm, 1.7??m) with gradient profile at a flow of 0.45?mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transition of m/z 426.3?175.2 was used to quantify for domperidone. The linearity of this method was found to be within the concentration range of 0.25-100.0?ng/mL for domperidone in human plasma. Only 1.5?min was needed for an analytical run. The method herein described was superior to previous methods and was successfully applied to the pharmacokinetic study of domperidone in healthy Chinese volunteers after oral administration. PMID:24549964

Qiu, X-J; Zheng, S-L; Wang, Y-F; Wang, R; Ye, L

2014-06-01

7

A rapid and sensitive UPLC-MS/MS method for determination of HZ08 in rat plasma and tissues: Application to a pharmacokinetic study of liposome injections.  

PubMed

Overexpression of P-glycoprotein leads to tumor multidrug resistance (MDR). HZ08, a novel tetrahydro-isoquinoline derivate, was discovered to inhibit the MDR in the cancer cell lines of MCF-7/ADM, K562/ADM and KBV in our previous studies. A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was developed and validated for determination of HZ08 in rat plasma and tissues after intravenous administration of HZ08 liposome injection at different doses. The analytes were extracted from plasma and tissues using protein precipitation by acetonitrile with clotrimazole as internal standard. The chromatographic separation was performed on a Thermo BDS HYPERSIL C18 column (100mm4.6mm, 2.4?m) at a flow rate of 0.7ml/min using 0.2% ammonium acetate solution (containing 0.1% formic acid) and methanol as mobile phase. The total run time was 4min. The tandem mass detection was applied with electrospray ionization in positive ion selected reaction monitoring mode. The ion transitions monitored were m/z 523.5 to 342.3 for HZ08 and 277.1 to 165.1 for the internal standard, respectively. The calibration curves obtained were linear in different matrices, and the lower limit of quantification (LLOQ) achieved was 1ng/ml for rat plasma and 0.25ng/ml for rat tissues, respectively. The RSDs for intra- and inter-day precision were less than 15%. Extraction recovery, matrix effect and stability were satisfactory in rat plasma and tissues. The developed method was successfully applied to a pharmacokinetic study of HZ08 liposome injection following intravenous administration of 1, 3, 10mg/kg to Sprague-Dawley rats. The data profiles revealed that HZ08 had linear pharmacokinetic properties at the tested doses, and was rapidly distributed into the systemic circulation with wide distribution throughout the body followed by a rapid elimination phase. The major distribution tissues of HZ08 in rats were lung, spleen and liver. These results provided constructive contribution to support the clinical evaluation. PMID:25305722

Yan, Fang; Sun, Miaomiao; Hang, Taijun; Sun, Jing; Zhou, Xia; Deng, Xin; Ge, Liang; Qian, Hai; Ya, Ding; Huang, Wenlong

2015-01-01

8

UPLC-MS(E) application in disease biomarker discovery: the discoveries in proteomics to metabolomics.  

PubMed

In the last decade, proteomics and metabolomics have contributed substantially to our understanding of different diseases. Proteomics and metabolomics aims to comprehensively identify proteins and metabolites to gain insight into the cellular signaling pathways underlying disease and to discover novel biomarkers for screening, early detection and diagnosis, as well as for determining prognoses and predicting responses to specific treatments. For comprehensive analysis of cellular proteins and metabolites, analytical methods of wider dynamic range higher resolution and good sensitivity are required. Ultra performance liquid chromatography-mass spectrometry(Elevated Energy) (UPLC-MS(E)) is currently one of the most versatile techniques. UPLC-MS(E) is an established technology in proteomics studies and is now expanding into metabolite research. MS(E) was used for simultaneous acquisition of precursor ion information and fragment ion data at low and high collision energy in one analytical run, providing similar information to conventional MS(2). In this review, UPLC-MS(E) application in proteomics and metabolomics was highlighted to assess protein and metabolite changes in different diseases, including cancer, neuropsychiatric pharmacology studies from clinical trials and animal models. In addition, the future prospects for complete proteomics and metabolomics are discussed. PMID:24631021

Zhao, Ying-Yong; Lin, Rui-Chao

2014-05-25

9

Determination of caramel colorants' by-products in liquid foods by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).  

PubMed

2-Methylimidazole, 4-methylimidazole (2-MI and 4-MI), 2-acetyl-4-(1,2,3,4-tetrahydroxybutyl) imidazole (THI) and 5-hydroxymethylfurfural (5-HMF) are neo-formed compounds generated during the manufacture of caramel colours and are transferred to the processed food. These contaminants are known to have a toxicological profile that may pose health risks. Hence, to characterise THI, 2- and 4-MI and 5-HMF levels in liquid foods, an ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and sample preparation was divided into two analytical strategies depending on the concentration range expected in the type of foods targeted. For the determination of the imidazole substitutes (THI, 2- and 4-MI), a sample enrichment and clean-up step by strong cation solid-phase extraction was developed. This method is capable of quantifying over a range of 5ngml(-1) (LOQ) to 500ngml(-1) with recoveries of 75.4-112.4% and RSDs of 1.5-15%. For determination of 5-HMF, a standard addition method was applied covering the linear range of 0.25-30gml(-1) with RSDs from 2.8% (for intraday precision) to 9.2% (for intermediate precision). The validated analytical methods were applied to 28 liquid food samples purchased from local markets. THI was found only in the beer samples at levels up to 141.2ngml(-1). For 2-MI, non-quantifiable traces were observed for all samples, while 4-MI was observed in all samples with large concentration variations (from high level of dilution before following the standard addition protocol. PMID:25060737

Goscinny, Sverine; Hanot, Vincent; Trabelsi, Hasna; Van Loco, Joris

2014-10-01

10

Development and validation of a simple and sensitive method for quantification of levodopa and carbidopa in rat and monkey plasma using derivatization and UPLC-MS/MS.  

PubMed

A simple, selective, and sensitive quantitative method has been developed for the simultaneous determination of levodopa and carbidopa in rat and monkey plasma by protein precipitation using acetonitrile containing the derivatizing reagent, flourescamine. Derivatized products of levodopa and carbidopa were separated on a BEH C18 column (2.1 mm 50 mm; 1.7 ?m particle size) using ultra high performance liquid chromatography (UHPLC) without any further purification. Tandem mass spectrometry (MS/MS) was used for detection. The method was validated over the concentration range of 5-5000 ng/mL and 3-3000 ng/mL for levodopa and carbidopa, respectively in rat and monkey plasma. Due to the poor stability of the investigated analytes in biological matrices, a mixture of sodium metabisulfite and hydrazine dihydrochloride was used as a stabilizer. This method was successfully utilized to support pharmacokinetic studies in both species. The results from assay validations and incurred samples re-analysis show that the method is selective, sensitive and robust. To our knowledge, this is the first UHPLC-MS/MS based method that utilizes derivatization with fluorescamine and provides adequate sensitivity for both levodopa and carbidopa with 50 ?L of sample and a run time of 3.5 min. PMID:23548675

Junnotula, Venkatraman; Licea-Perez, Hermes

2013-05-01

11

Therapeutic monitoring of amphotericin B in Saudi ICU patients using UPLC MS/MS assay.  

PubMed

Amphotericin B (AmB) is the first-line agent for the treatment of life-threatening invasive fungal infections. The aim of this study was to monitor AmB in critically ill Saudi patients in ICU after i.v. administration of 0.68 0.1 mg/kg/day Fungizone. A selective, sensitive and precise UPLC MS/MS method was developed to measure AmB concentrations in these patients. Seven ICU patients with creatinine clearance (ClCr) >40 mL/min were included. AmB levels were analyzed using a Waters Aquity UPLC MS/MS system, a BEH Shield RP18 column and detection via electrospray ionization source with positive ionization mode. The precision and accuracy of the developed UPLC method in the concentration range of 200-4000 ng/mL show no significant difference among inter- and-intra-day analysis (p > 0.05). Linearity was observed over the investigated range with correlation coefficient, r > 0.995 (n = 6/day). The pharmacokinetics of AmB in these patients, at steady state, showed a high terminal half-life of 124.6 73.4 h, with a highest concentration of 513.9 281.1 ng/mL, a lowest concentration 316.4 129.0 ng/mL and a mean clearance 91.1 39.2 mL/h/kg. The pharmacokinetics of AmB in critically ill Saudi patients in ICU was studied using a fully validated assay. A weak correlation (r = -0.22) of AmB Cl with ClCr was obtained, which suggests the need for further investigation in a larger population. Copyright 2014 John Wiley & Sons, Ltd. PMID:24733605

Al-Quadeib, Bushra T; Radwan, Mahasen A; Siller, Lidija; Mutch, Elaine; Horrocks, Ben; Wright, Matthew; Alshaer, Abdulaziz

2014-12-01

12

Identifying static and kinetic lipid phenotypes by high resolution UPLC-MS: unraveling diet-induced changes in lipid homeostasis by coupling metabolomics and fluxomics.  

PubMed

A novel method to differentiate diet-induced alterations in plasma lipid phenotypes "static (concentration of lipids) and kinetic (endogenous production, e.g., denovo lipogenesis)" was employed. C57Bl6 mice were randomized into 2 groups and fed either a high-carbohydrate, low-fat (HC) or a carbohydrate-free, high-fat diet (HF) diet for 13 days; D(2)O was administered via intraperitoneal injection and then adding D(2)O to the drinking water for 96 h. Principal component analysis (PCA) revealed differences in the plasma lipid content, for example, triglycerides (TG) 50:2, 50:3, and 52:2 were up-regulated in mice fed the HC diet, whereas TG 52:4, 52:1, 54:5, 54:3, 54:4, and 54:2 were higher in animals fed the HF diet. However, although the fractional contribution of synthesis was ~10-fold lower in HF vs HC fed mice, changes in TG concentration were not entirely mediated by altered de novo lipogenesis. In addition, the ability to couple isotope labeling measurements with PCA analyses revealed cases where there were no differences in the concentration of a compound but its source was substantially altered. In summary, this strategy determined (i) the presence/absence of differences in concentration and (ii) the contribution of different pathways and synthesis that could affect lipid biology in a mouse model respectively. PMID:21744776

Castro-Perez, Jose M; Roddy, Thomas P; Shah, Vinit; McLaren, David G; Wang, Sheng-Ping; Jensen, Kristian; Vreeken, Rob J; Hankemeier, Thomas; Johns, Douglas G; Previs, Stephen F; Hubbard, Brian K

2011-09-01

13

UPLC\\/MS for the identification of ?-blockers  

Microsoft Academic Search

The ?-blockers Oxprenolol, Metoprolol, Acebutolol, Atenolol, Propranolol, Pindolol, and Alprenolol were analysed by both UPLC\\/MS and HPLC\\/MS using mobile phases containing acetonitrile, TFA and either H2O or D2O. UPLC gave superior separation performance and the quality of the mass spectra were at least as good as those from HPLC.

Stephen A. C. Wren; Pierre Tchelitcheff

2006-01-01

14

UPLC/MS for the identification of beta-blockers.  

PubMed

The beta-blockers Oxprenolol, Metoprolol, Acebutolol, Atenolol, Propranolol, Pindolol, and Alprenolol were analysed by both UPLC/MS and HPLC/MS using mobile phases containing acetonitrile, TFA and either H2O or D2O. UPLC gave superior separation performance and the quality of the mass spectra were at least as good as those from HPLC. PMID:16413161

Wren, Stephen A C; Tchelitcheff, Pierre

2006-02-24

15

Determination of sotolon content in South African white wines by two novel HPLC-UV and UPLC-MS methods.  

PubMed

Sotolon has been reported to play an important role in the atypical ageing and aroma character of many wines. A number of analytical techniques for sotolon analysis in wine have been reported, but these often require extensive sample preparation. In this work we report a HPLC-UV method and a novel UPLC-MS method to determine sotolon concentrations in white wines with little sample preparation applied for the first time for the evaluation of sotolon levels in South African wines. The validation showed that the instrumental methods had good accuracy, repeatability and linearity, but the UPLC-MS method proved more sensitive. For both methods, quantification limits were lower than the sotolon odour threshold in wine (10?g/L), 0.86?g/L and 0.013?g/L, for HPLC-UV and UPLC-MS methods, respectively. Sotolon levels in 65 South African white wines were often found to be lower than the reported odour threshold, with the highest concentration being 9.11?g/L. However, for low levels (<1?g/L), unknown interferences in certain wines led to sotolon not being quantified with the HPLC-UV method, which made the UPLC-MS method more suitable. PMID:25236214

Gabrielli, Mario; Buica, Astrid; Fracassetti, Daniela; Stander, Marietjie; Tirelli, Antonio; du Toit, Wessel J

2015-02-15

16

Global metabolic profiling procedures for urine using UPLCMS  

Microsoft Academic Search

The production of 'global' metabolite profiles involves measuring low molecular-weight metabolites (<1 kDa) in complex biofluids\\/tissues to study perturbations in response to physiological challenges, toxic insults or disease processes. Information-rich analytical platforms, such as mass spectrometry (MS), are needed. Here we describe the application of ultra-performance liquid chromatographyMS (UPLCMS) to urinary metabolite profiling, including sample preparation, stability\\/storage and the selection

Ian D Wilson; Helen Gika; Georgios Theodoridis; Robert S Plumb; John Shockcor; Elaine Holmes; Jeremy K Nicholson; Elizabeth J Want

2010-01-01

17

Determination of pergolide in horse plasma by UPLC-MS/MS for pharmacokinetic applications.  

PubMed

Pergolide, an ergot-derived dopamine D2 receptor agonist, is used extensively as an orally administered treatment for pituitary pars intermedia dysfunction (PPID) in horses. One of the barriers associated with pergolide determinations in plasma for pharmacokinetic applications has been the technically demanding requirement for sensitivity. The objective of our work was to develop a simple assay for the determination of pergolide in plasma and demonstrate its potential application in the study of pergolide pharmacokinetics (PK) in horses. A UPLC-MS/MS assay was developed with a simple sample preparation involving methanol protein precipitation and injection of supernatant. The assay was applied to samples from a horse dosed with 10mg pergolide (as the mesylate salt) by nasogastric intubation. Plasma samples were collected over a 48h period. The assay demonstrated performance sufficient to enable application to low level PK studies. Within-batch precision and accuracy were within acceptance criteria; precision was less than 10% RSD (n=5) and accuracy was -7.3% at 0.014ng/mL, the lower limit of quantification was 0.006ng/mL and the method detection limit was 0.002ng/mL. In the treated horse, Cmax was 0.40ng/mL and the assay easily allowed determination of plasma levels in the elimination phase to 48h. In conclusion, this assay using UPLC-MS/MS and methanol protein precipitation easily meets the challenging demands of pergolide analyses in plasma. PMID:24549007

Jacobson, Glenn A; Pirie, Adam; Edwards, Scott; Hughes, Kristopher J; Rendle, David I; Davies, Noel W

2014-06-01

18

Multimycotoxin UPLC-MS/MS for tea, herbal infusions and the derived drinkable products.  

PubMed

In recent years the consumption of tea and herbal infusions has increased. These hot drinks are consumed as daily drinks as well as for medicinal purposes. All tea varieties (white, yellow, green, oolong, black and puerh) originate from the leaves of the tea plant, Camellia sinensis. All extracts made of plant or herbal materials which do not contain Camellia sinensis are referred as herbal infusions or tisanes. During processing and manufacturing fungal contamination of the plant materials is possible, enabling contamination of these products with mycotoxins. In this study a multimycotoxin UPLC-MS/MS method was developed and validated for the analysis of the raw tea and herbal infusion materials as well as for their drinkable products. The samples were analyzed by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS), with a mobile phase consisting of variable mixtures of water and methanol with 0.3% formic acid. The limits of detection for the different mycotoxins varied between 2.1 ?g/kg and 121 ?g/kg for raw materials and between 0.4 ?g/L and 46 ?g/L for drinkable products. Afterward 91 different tea and herbal infusion samples were analyzed. Only in one sample, Ceylon melange, 76 ?g/kg fumonisin B(1) was detected. No mycotoxins were detected in the drinkable products. PMID:21121648

Monbaliu, Sofie; Wu, Aibo; Zhang, Dabing; Van Peteghem, Carlos; De Saeger, Sarah

2010-12-22

19

Rapid and simultaneous quantitation of prostanoids by UPLC-MS/MS in rat brain.  

PubMed

The metabolites of arachidonic acid (AA) produced from the cyclooxygenase (COX) pathway, collectively termed as prostanoids, and from the CYP 450 pathway, eicosanoids, have been implicated in various neuro-degenerative and neuroinflammatory diseases. This study developed a quantitative UPLC-MS/MS method to simultaneously measure 11 prostanoids including prostaglandins and cyclopentenone metabolites in the rat brain cortical tissue. Linear calibration curves ranging from 0.104 to 33.3ng/ml were validated. The inter-day and intra-day variance for all metabolites was less than 15%. The extraction recovery efficiency and matrix (deionized water) effects measured at 12.5ng/ml (750pg on column) ranged from 88 to 100% and 3 to 14%, respectively, with CV% values below 20%. Additionally, applying the processing and extraction conditions of this method to our previous CYP450 eicosanoids method resulted in overall improvement in extraction recovery and reduction in matrix effects at low (0.417ng/ml) and high (8.33ng/ml) concentrations. In rat brain cortical tissue samples, concentrations of prostanoids ranged from 10.2 to 937pmol/g wet tissue and concentration of eicosanoids ranged from 2.23 to 793pmol/g wet tissue. These data demonstrate that the successive measurement of prostanoids and eicosanoids from a single extracted sample of rat brain tissue can be achieved with a UPLC-MS/MS system and that this method is necessary for evaluation of these metabolites to delineate their role in various neuroinflammatory and cerebrovascular disorders. PMID:24355215

Shaik, Jafar Sadik B; Miller, Tricia M; Graham, Steven H; Manole, Mioara D; Poloyac, Samuel M

2014-01-15

20

Integrated metabolomic profiling of hepatocellular carcinoma in hepatitis C cirrhosis through GC/MS and UPLC/MS-MS  

PubMed Central

Background & Aims The metabolic pathway disturbances associated with hepatocellular carcinoma (HCC) remain unsatisfactorily characterized. Determination of the metabolic alterations associated with the presence of HCC can improve our understanding of the pathophysiology of this cancer and may provide opportunities for improved disease monitoring of patients at risk for HCC development. To characterize the global metabolic alterations associated with HCC arising from hepatitis C (HCV)-associated cirrhosis using an integrated non-targeted metabolomics methodology employing both gas chromatography/mass spectrometry (GC/MS) and ultrahigh-performance liquid chromatography/electrospray ionization tandem mass spectrometry (UPLC/MS-MS). Methods The global serum metabolomes of 30 HCC patients, 27 hepatitis C cirrhosis disease controls and 30 healthy volunteers were characterized using a metabolomics approach that combined two metabolomics platforms, GC/MS and UPLC/MS-MS. Random forest, multivariate statistics and receiver operator characteristic analysis were performed to identify the most significantly altered metabolites in HCC patients vs. HCV-cirrhosis controls and which therefore exhibited a close association with the presence of HCC. Results Elevated 12-hydroxyeicosatetraenoic acid (12-HETE), 15-HETE, sphingosine, ?-glutamyl oxidative stress-associated metabolites, xanthine, amino acids serine, glycine and aspartate, and a-cylcarnitines were strongly associated with the presence of HCC. Elevations in bile acids and dicarboxylic acids were highly correlated with cirrhosis. Conclusions Integrated metabolomic profiling through GC/MS and UPLC/MS-MS identified global metabolic disturbances in HCC and HCV-cirrhosis. Aberrant amino acid biosynthesis, cell turnover regulation, reactive oxygen species neutralization and eicosanoid pathways may be hallmarks of HCC. Aberrant dicarboxylic acid metabolism, enhanced bile acid metabolism and elevations in fibrinogen cleavage peptides may be signatures of cirrhosis. PMID:24661807

Fitian, Asem I.; Nelson, David R.; Liu, Chen; Xu, Yiling; Ararat, Miguel; Cabrera, Roniel

2014-01-01

21

Development and Validation of a UPLC-MS/MS Method to Monitor Cephapirin Excretion in Dairy Cows following Intramammary Infusion  

PubMed Central

Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 g kg?1 and 0.96 g L?1 for feces and urine, respectively. This robust method recovered >60% and >80% cephapirin from spiked blank fecal and urine samples, respectively, with acceptable intra- and inter-day variation (<10%). Using this method, we detected trace amounts (g kg?1) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 g L?1). Cephapirin was primarily excreted via urine and its urinary excretion was influenced by day (P?=?0.03). Peak excretion (2.69 mg) was on day 1 following intramammary infusion and decreased sharply thereafter (0.19, 0.19, 0.08, and 0.17 mg on day 2, 3, 4, and 5, respectively) reflecting a quadratic pattern of excretion (Quadratic: P?=?0.03). The described method for quantification of cephapirin in bovine feces and urine is sensitive, accurate, and robust and allowed to monitor the pattern of cephapirin excretion in dairy cows. This data will help develop manure segregation and treatment methods to minimize the risk of antibiotic loading to the environment from dairy farms. PMID:25375097

Ray, Partha; Knowlton, Katharine F.; Shang, Chao; Xia, Kang

2014-01-01

22

UPLC-MS/MS quantification of nanoformulated ritonavir, indinavir, atazanavir, and efavirenz in mouse serum and tissues.  

PubMed

Animal pharmacokinetic and tissue distribution assays of antiretroviral therapeutic drugs require accurate drug quantification in biological fluids and tissues. Here we report a simple, rapid, and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for quantification of commonly used antiretroviral drugs ritonavir (RTV), indinavir (IDV), atazanavir (ATV), and efavirenz (EFV) in mouse serum and tissues (liver, kidney, lung, and spleen). These antiretroviral drugs are currently the cornerstones of common therapeutic regimens for human immunodeficiency virus (HIV) infection. Chromatographic separation was achieved using a gradient mobile phase (5% acetonitrile in methanol and 7.5mM ammonium acetate (pH 4.0)) on an ACQUITY UPLC()BEH Shield RP 18 column. All compounds eluted within a 7 min run time. Lopinavir was used as an internal standard. Detection was achieved by dual positive and negative ionization modes on a quadrupole linear ion trap hybrid mass spectrometer with an electrospray ionization (ESI) source. The dynamic range was 0.2-1000 ng/mL for RTV, IDV, and ATV, and 0.5-1000 for EFV. The method was validated and showed high and consistent intra-day and inter-day accuracy and precision for all analytes. This method is used to support the preclinical development studies of targeted- and sustained-release combination ART (nanoART). The current data demonstrate a 1.5-4 fold increase in serum and tissue AUC of nanoformulated ATV, RTV, and EFV administered to mice when compared to native drug. In addition, the tested formulation enhanced exposure of the same anti-HIV drugs in mouse tissues. PMID:21752731

Huang, Jiangeng; Gautam, Nagsen; Bathena, Sai Praneeth R; Roy, Upal; McMillan, JoEllyn; Gendelman, Howard E; Alnouti, Yazen

2011-08-01

23

Detection of ?-methylphenethylamine, a novel doping substance, by means of UPLC/MS/MS.  

PubMed

Novel substances of expected doping activity are constantly introduced to the market. ?-Methylphenethylamine (BMPEA) is classified as a doping agent by the World Anti-Doping Agency as it is a positional isomer of amphetamine. In this work, the development and application of a simple and rapid analytical procedure that enables discrimination between both isomers is described. The analytes of interest were extracted from urine by a two-step liquid-liquid extraction and then analyzed by UPLC/MS/MS under isocratic conditions. The entire analytical procedure was validated by evaluating its selectivity, discrimination capabilities, carry-over, sensitivity, and influence of matrix effects on its performance. Application of the method resulted in detection of BMPEA in eight anti-doping samples, including the first report of adverse analytical finding regarding its use. Further analysis showed that BMPEA may be eliminated unchanged along with its phase II conjugates, the hydrolysis of which may considerably improve detection capabilities of the method. Omission of the hydrolysis step may therefore, produce false-negative results. Testing laboratories should also carefully examine their LC/MS/MS-based amphetamine and BMPEA findings as both isomers fragment yielding comparable collision-induced dissociation spectra and their insufficient chromatographic separation may result in misidentification. This is of great importance in case of forensic analyses as BMPEA is not controlled by the public law, and its manufacturing, distribution, and use are legal. PMID:24633566

Cho?bi?ski, Piotr; Wicka, Mariola; Kowalczyk, Katarzyna; Jarek, Anna; Kaliszewski, Pawe?; Pokrywka, Andrzej; Bulska, Ewa; Kwiatkowska, Dorota

2014-06-01

24

Photocatalytic degradation of hexazinone and its determination in water via UPLC-MS/MS.  

PubMed

Degradation of hexazinone has been investigated by means of photocatalysis of mixed-phase crystal nano-TiO(2). Influences of adsorption, amount of nano-TiO(2), pH and irradiation time on the photocatalytic process are studied. Results show that hexazinone is totally degraded within 40min of irradiation under pH neutral conditions. This compares favorably with Degussa P25 TiO(2) when conducted under the same experimental conditions. Preliminary photocatalytic kinetic information for hexazinone degradation is proposed. First order kinetics is obtained for the adsorption and photocatalytic degradation reactions, which fit the Langmuir-Hinshelwood model. A rapid, sensitive and accurate UPLC-MS/MS technique is developed and utilized to determine the level of hexazinone in water in support of the degradation kinetics study. The results indicate a limit of detection (LOD) at 0.05?g/l and the recoveries between 90.2 and 98.5% with relative standard deviations (RSD) lower than 12%. A LC-MS/MS technique is used to trace the degradation process. Complete degradation is achieved into final products including nontoxic water, carbon dioxide and urea. A probable pathway for the total photocatalytic degradation of hexazinone is proposed. PMID:22551636

Mei, Mei; Du, Zhenxia; Xu, Ruifen; Chen, Yun; Zhang, Haojie; Qu, Shuping

2012-06-30

25

Inhibition of the isoprenoid biosynthesis pathway; detection of intermediates by UPLC-MS/MS.  

PubMed

The isoprenoid biosynthesis pathway provides the cell with a variety of compounds which are involved in multiple cellular processes. Inhibition of this pathway with statins and bisphosphonates is widely applied in the treatment of hypercholesterolemia and metabolic bone disease, respectively. In addition, since isoprenylation of proteins is an important therapeutic target in cancer research there is interest in interfering with isoprenoid biosynthesis, for which new inhibitors to block farnesylation and geranylgeranylation of small GTPases are being developed. We recently developed a sensitive method using UPLC-MS/MS that allows the direct detection and quantification of all intermediates of the mevalonate pathway from MVA to GGPP which can be used to verify the specificity of inhibitors of the isoprenoid biosynthesis pathway. We here investigated the specificity of several inhibitors of the isoprenoid biosynthesis pathway in HepG2 cells, fibroblasts and lymphoblasts. The nitrogen-containing bisphosphonates pamidronate and zoledronate specifically inhibit farnesyl pyrophosphate synthase indicated by the accumulation of IPP/DMAPP. However, zaragozic acid A, a squalene synthase inhibitor, causes an increase of MVA in addition to the expected increase of FPP. Analysis of isoprenoid intermediate profiles after incubation with 6-fluoromevalonate showed a very nonspecific result with an increase in MVA, MVAP, MVAPP and IPP/DMAPP. These results show that inhibitors of a particular enzyme of the isoprenoid biosynthesis pathway can have additional effects on other enzymes of the pathway either direct or indirect through accumulation of isoprenoid intermediates. Our method can be used to test new inhibitors and their effect on overall isoprenoid biosynthesis. PMID:21237288

Henneman, Linda; van Cruchten, Arno G; Kulik, Willem; Waterham, Hans R

2011-04-01

26

Simultaneous determination of 30 hormones illegally added to anti-ageing functional foods using UPLC-MS/MS coupled with SPE clean-up.  

PubMed

A novel analytical method employing solid-phase extraction (SPE) coupled with ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the simultaneous determination of 30 hormones in anti-ageing functional foods (capsules, powders and tablets). The analytes were extracted with acetic acid-acetonitrile (1-99v/v), methanol and acetone, respectively. The extract was purified using a combined column, followed by analyte detection with electrospray ionisation in positive- or negative-ion modes. The results indicated that the 30 compounds had good linear correlations in the range of 1-1000?gkg(-1), and the correlation coefficients were above 0.99. The limits of detection (LOD) and limits of quantification (LOQ) were 0.03-2 and 0.1-5?gkg(-1), respectively. The average recovery of 30 compounds at the three spiked levels varied from 74.7% to 124.1%, and the relative standard deviation (RSD) was 2.4-15.0%. This method was applied to the analysis of hormones in 14 real samples of which seven hormones (such as estrone, dienestrol) were detected in four samples, but the remainder of the hormones were not detected. The developed method is sensitive, efficient, reliable and applicable to real samples. PMID:25188907

He, Xiaoqin; Xi, Cunxian; Tang, Bobin; Wang, Guomin; Chen, Dongdong; Peng, Tao; Mu, Zhaode

2014-10-01

27

Removal of malathion from aqueous solution using De-Acidite FF-IP resin and determination by UPLC-MS/MS: equilibrium, kinetics and thermodynamics studies.  

PubMed

In the present study, De-Acidite FF-IP resin was used to remove a highly toxic and persistent organophosphorus pesticide (malathion) from the aqueous solution. Batch experiments were performed as a function of various experimental parameters such as effect of pH (2-10), contact time (10-120 min), resin dose (0.05-0.5 g), initial malathion concentration (0.5-2.5 g mL(-1)) and temperature (25-65C). The concentration of malathion was determined using a sensitive, selective and rapid ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method. The uptake rate of malathion on De-Acidite FF-IP resin was rapid and equilibrium established within 40 min. Kinetics studies showed better applicability for pseudo-second-order model. The equilibrium data was fitted to Langmuir and Freundlich isotherm models and the isotherm constants were calculated for malathion. The values of thermodynamic parameters (?G(0), ?H(0) and ?S(0)) were computed from the Van't Hoff plot of lnKC vs. 1/T which showed that the adsorption of malathion was feasible, endothermic and spontaneous. The regeneration studies were carried out which demonstrated a decrease in the recovery of malathion from 95% to 68% after five consecutive cycles. Breakthrough and exhaustive capacities of malathion were found to be 1.25 mg g(-1) and 3.5 mg g(-1), respectively. PMID:24054556

Naushad, Mu; Alothman, Z A; Khan, M R

2013-10-15

28

Reliable quantification of bisphenol A and its chlorinated derivatives in human urine using UPLC-MS/MS method.  

PubMed

Bisphenol A (BPA), a widespread man-made chemical classified as an endocrine disruptor, is increasingly considered as a major cause of concern for human health. Chlorine present in drinking water may react with BPA to form chlorinated derivatives (ClxBPA), which have demonstrated a heightened level of estrogenic activity. If many epidemiological studies report that more than 90% of people have detectable BPA levels in their urine, then no such study has been undertaken regarding ClxBPA. The purpose of this work is to propose a highly sensitive and accurate analytical method adapted to large-scale biomonitoring studies aimed at assessing exposure to BPA and ClxBPA through the use of human urine. To achieve this, we have comprehensively validated a method using salting-out assisted liquid/liquid extraction (SALLE) coupled to UPLC-MS/MS and isotope dilution quantification, to measure unconjugated BPA and ClxBPA in human urine according to the accepted guidelines. Deutered BPA as well as deutered 2,2'-DCBPA was used as internal standards. The matrix calibration curve ranged from 0.05 to 1.60 ng mL(-1) and from 0.5 to 16.0 ng mL(-1) for ClxBPA and BPA respectively, and provided good linearity (r>0.99). This method was precise (the intra- and inter-day coefficients of variation were <20% at three different concentrations: 0.05 ng mL(-1), 0.2 ng mL(-1), 0.8 ng mL(-1) and 0.5 ng mL(-1), 2 ng mL(-1), 8 ng mL(-1) for ClxBPA and BPA, respectively) and accurate (bias ranged from -13% to +12%). The limit of quantification, validated at 0.05 ng mL(-1) and 0.5 ng mL(-1) for ClxBPA and BPA respectively when using 300 L of urine, was found to be suitable for the concentration existing in real samples. The matrix effect and the BPA cross-contamination were also investigated in this study. The analytical method developed in this study is in accordance with the requirements applicable to biomonitoring of BPA and ClxBPA in human urine. PMID:24840445

Venisse, N; Grignon, C; Brunet, B; Thvenot, S; Bacle, A; Migeot, V; Dupuis, A

2014-07-01

29

Determination of mangiferin in rat plasma by liquidliquid extraction with UPLCMS\\/MS  

Microsoft Academic Search

An ultra-performance liquid chromatography tandem mass spectrometry (UPLCMS\\/MS) method employing electrospray ionization (ESI) has been developed for the determination of mangiferin in rat plasma using diphenhydramine as the internal standard (IS). Liquidliquid extraction (LLE) was used for sample preparation and the analysis was achieved with gradient elution on C18 reversed phase column. The method was validated over the concentration range

Dandan Han; Chengjun Chen; Cong Zhang; Yu Zhang; Xing Tang

2010-01-01

30

Validated UPLC-MS/MS assay for the determination of synthetic phosphodiesterase type-5 inhibitors in postmortem blood samples.  

PubMed

The use of synthetic phosphodiesterase type 5 (PDE-5) inhibitors for the treatment of erectile dysfunction: sildenafil citrate (Viagra()), tadalafil (Cialis()) and vardenafil hydrochloride (Levitra()) has increased dramatically over the past 2 years. These substances are prescription drugs and must be used under medical supervision. However, they can easily be obtained over the internet from illegal sites, being a potential for a threat to public health. The development of an electrospray ionisation (ESI) ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) procedure for the simultaneous identification and quantification of three PDE5 inhibitors in blood samples was desired. Samples were prepared using Oasis() HLB solid-phase cartridges (3 cc, 60 mg) and chromatographic separation was achieved on an Acquity UPLC() HSS T3 (100 2.1 mm i.d., 1.8 ?m particles) column with a gradient mobile phase of 0.1% formic acid and acetonitrile at a 0.5 mL/min flow rate. Quantification was achieved by multiple reaction monitoring (MRM) of two transitions per compound: m/z 475.1 > 58 e m/z 475.1 > 311.1 for sildenafil; m/z 389.9 > 267.9 e m/z 389.9 > 134.8 for tadalafil and m/z 489 > 71.9 e m/z 489 > 150.9 for vardenafil. Zolpidem-d6 (m/z 314.5 > 235.3) was used as the internal standard. Calibration curves were linear over the concentration range of 5-1000 ng/mL, with a coefficient of determination better than 0.997. The lower limits of detection and quantification for these substances were ? 3 ng/mL and ? 8 ng/mL, respectively. The method showed a satisfactory sensitivity, precision, accuracy, recovery and selectivity. A rapid, selective and sensitive UPLC-MS/MS method using solid-phase extraction was developed for the simultaneous determination and quantification of sildenafil, vardenafil and tadalafil in blood samples. PMID:23910856

Proena, Paula; Mustra, Carla; Marcos, Mariana; Franco, Joo Miguel; Corte-Real, Francisco; Vieira, Duarte Nuno

2013-08-01

31

Pharmacokinetics of Dibutyl Phthalate (DBP) in the Rat Determined by UPLC-MS/MS  

PubMed Central

Dibutyl phthalate (DBP) is commonly used to increase the flexibility of plastics in industrial products. However, several plasticizers have been illegally used as clouding agents to increase dispersion of aqueous matrix in beverages. This study thus develops a rapid and validated analytical method by ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) for the evaluation of pharmacokinetics of DBP in free moving rats. The UPLC-MS/MS system equipped with positive electrospray ionization (ESI) source in multiple reaction monitoring (MRM) mode was used to monitor m/z 279.25?148.93 transitions for DBP. The limit of quantification for DBP in rat plasma and feces was 0.05 ?g/mL and 0.125 ?g/g, respectively. The pharmacokinetic results demonstrate that DBP appeared to have a two-compartment model in the rats; the area under concentration versus time (AUC) was 57.8 5.93 min ?g/mL and the distribution and elimination half-life (t1/2,? and t1/2,?) were 5.77 1.14 and 217 131 min, respectively, after DBP administration (30 mg/kg, i.v.). About 0.18% of the administered dose was recovered from the feces within 48 h. The pharmacokinetic behavior demonstrated that DBP was quickly degraded within 2 h, suggesting a rapid metabolism low fecal cumulative excretion in the rat. PMID:23344044

Chang, Li-Wen; Hou, Mei-Ling; Tsai, Tung-Hu

2013-01-01

32

Pharmacokinetics of Dibutyl Phthalate (DBP) in the Rat Determined by UPLC-MS/MS.  

PubMed

Dibutyl phthalate (DBP) is commonly used to increase the ?exibility of plastics in industrial products. However, several plasticizers have been illegally used as clouding agents to increase dispersion of aqueous matrix in beverages. This study thus develops a rapid and validated analytical method by ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) for the evaluation of pharmacokinetics of DBP in free moving rats. The UPLC-MS/MS system equipped with positive electrospray ionization (ESI) source in multiple reaction monitoring (MRM) mode was used to monitor m/z 279.25?148.93 transitions for DBP. The limit of quanti?cation for DBP in rat plasma and feces was 0.05 g/mL and 0.125 g/g, respectively. The pharmacokinetic results demonstrate that DBP appeared to have a two-compartment model in the rats; the area under concentration versus time (AUC) was 57.8 5.93 min ?g/mL and the distribution and elimination half-life (t(1/2,?) and t(1/2,?)) were 5.77 1.14 and 217 131 min, respectively, after DBP administration (30 mg/kg, i.v.). About 0.18% of the administered dose was recovered from the feces within 48 h. The pharmacokinetic behavior demonstrated that DBP was quickly degraded within 2 h, suggesting a rapid metabolism low fecal cumulative excretion in the rat. PMID:23344044

Chang, Li-Wen; Hou, Mei-Ling; Tsai, Tung-Hu

2013-01-01

33

UPLC-MS/MS Determination of Phentolamine in Human Plasma and its Application to a Pharmacokinetic Study.  

PubMed

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine phentolamine in human plasma. Sample preparation was accomplished through a simple liquid-liquid extraction with ethyl acetate. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using an isocratic mobile phase system composed of acetonitrile and 1% formic acid in water (33:67, v/v) at a flow rate of 0.45?mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transitions of m/z 282.1 ? 212.0 and m/z 237.1 ? 194.2 were used to quantify for phentolamine and carbamazepine (internal standard, IS), respectively. The linearity of this method was found to be within the concentration range of 0.5-100.0?ng/mL with a lower limit of quantification of 0.5?ng/mL. Only 1.0?min was needed for an analytical run. This fully validated method was successfully applied to the pharmacokinetic study after oral administration of 60?mg phentolamine to 20 Chinese healthy male volunteers. PMID:24452521

Kan, X; Zheng, S-L; Zhou, C-Y

2014-11-01

34

Quantitative Determination of Ketoconazole by UPLC-MS/MS in Human Plasma and its Application to Pharmacokinetic Study.  

PubMed

In this study, a simple, rapid and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method is described for determination of ketoconazole (KTZ) in human plasma samples using carbamazepine as the internal standard (IS). Sample preparation was accomplished through one-step liquid-liquid extraction by ethyl acetate, and chromatographic separation was performed on an Acquity BEH C18 column (2.1?mm50?mm, 1.7??m) with gradient profile at a flow of 0.45?mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transition of m/z 531.2?489.3 was used to quantify for KTZ. The linearity of this method was found to be within the concentration range of 5-15?000?ng/mL for KTZ in human plasma. Only 1.5?min was needed for an analytical run. The method herein described was superior to previous methods and was successfully applied to the pharmacokinetic study of KTZ in healthy Chinese volunteers after oral administration. PMID:24452517

Hu, M-L; Xu, M; Ye, Q

2014-10-01

35

Comparative study of the LC-MS/MS and UPLC-MS/MS for the multi-residue analysis of quinolones, penicillins and cephalosporins in cow milk, and validation according to the regulation 2002/657/EC.  

PubMed

The aim of this study was to develop and validate an analytical method to simultaneously determine European Union-regulated ?-lactams (penicillins and cephalosporins) and quinolones in cow milk. The procedure involves a new solid phase extraction (SPE) to clean-up and pre-concentrate the three series of antibiotics before analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). LC-MS/MS and UPLC-MS/MS techniques were also compared. The method was validated according to the Directive 2002/657/EC and subsequently applied to 56 samples of raw cow milk supplied by the Laboratori Interprofessional Lleter de Catalunya (ALLIC) (Laboratori Interprofessional Lleter de Catalunya, Control Laboratory Interprofessional of Milk of Catalunya). PMID:21820979

Junza, A; Amatya, R; Barrn, D; Barbosa, J

2011-09-01

36

Simultaneous determination of bioactive components of Radix Angelicae Sinensis-Radix Paeoniae Alba herb couple in rat plasma and tissues by UPLC-MS/MS and its application to pharmacokinetics and tissue distribution.  

PubMed

A highly sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed and validated for simultaneous quantification of seven components in rat plasma and five components in rat tissues after oral administration of the extracts of different combination Radix Angelicae Sinensis-Radix Paeoniae Alba herb couple and has been applied to compare the different pharmacokinetics and tissue distribution properties of these bioactive components. The extracts of Radix Angelicae Sinensis (RAS), Radix Paeoniae Alba (RPA) and Radix Angelicae Sinensis-Radix Paeoniae Alba herb couple (RRHC) were orally administrated to rats, respectively. The concentrations of ferulic acid, caffeic acid, vanillic acid, ligustilide, paeoniflorin, albiflorin and oxypaeoniflorin in rat plasma and the concentrations of ferulic acid, vanillic acid, paeoniflorin, albiflorin and oxypaeoniflorin in tissues were determined by UPLC-MS/MS. The plasma samples were pretreated by protein precipitation with methanol and the tissue samples were homogenated with water and pretreated by protein precipitation with methanol. Chromatographic separation was performed on a C18 column using 0.1% formic acid-acetonitrile as mobile phase for gradient elution. A triple quadrupole (TQ) tandem mass spectrometry equipped with an electrospray ionization source was used as detector operating both in positive and negative ionization mode and operated by multiple-reaction monitoring (MRM) scanning. Noncompartmental pharmacokinetic parameters were calculated by DAS 2.0 program. The differences between each group were compared by SPSS 16.0 with Independent-Samples T-test. The pharmacokinetic parameters (such as Cmax, Tmax, T1/2, AUC0-T, MRT0-T, Vz/F or CLz/F) of all the detected components between the single herb (RAS or RPA) and herb pair (RRHP) showed significant differences (P<0.05). It indicated that the compatibility of RAS and RPA could alter the pharmacokinetics features of each component. Tissue distribution results showed that ferulic acid, vanillic acid, paeoniflorin, albiflorin and oxypaeoniflorin mostly distributed in liver and kidney both in herb couple and single herb distributed most in liver and kidney. Compared with single herb, RRHC could increase or decrease the concentrations of five components at different time points compared with the sing herb. The results indicated the method was successfully applied to the comparative study on pharmacokinetics and tissue distribution of different combination of RRHC in rats. The compatibility of two Chinese herbs could alter the pharmacokinetics and tissue distribution properties of major bio-active components in the single herb. The results might be helpful for further investigation of compatibility mechanism of RRHC. PMID:24927419

Luo, Niancui; Li, Zhenhao; Qian, Dawei; Qian, Yefei; Guo, Jianming; Duan, Jin-Ao; Zhu, Min

2014-07-15

37

Method Development and Validation for Pharmacokinetic and Tissue Distributions of Ellagic Acid Using Ultrahigh Performance Liquid Chromatography-Tandem Mass Spectrometry (UPLC-MS/MS).  

PubMed

Ellagic acid is a dietary polyphenol found in numerous fruits and vegetables, possessing several health benefits such as antioxidant, anticancer and anti-atherosclerotic biological properties. The purpose of this study was to explore the pharmacokinetics and tissue distribution of ellagic acid in rats. A simple, rapid, sensitive and specific liquid chromatography-tandem mass spectrometry method to determine the ellagic acid in plasma and tissue samples was developed and validated. The separation was achieved using reversed-phase ultra-performance liquid chromatography (UPLC), and the mass spectrometric detection was achieved using heated electrospray ionization (negative mode) and multiple ion monitoring (m/z 301/229). A sample cleanup with a solid phase extraction (SPE) step prior to the UPLC-MS/MS analysis was also developed. The SPE and UPLC-MS/MS method established here was successfully applied to reveal the pharmacokinetic profiles and tissue distribution of ellagic acid. After oral administration dosing at 50 mg/kg, plasma levels of ellagic acid peaked at about 0.5 h, with Cmax value of 93.6 ng/mL, and the results showed that the ellagic acid was poorly absorbed after oral administration. The pharmacokinetic profile of ellagic acid fitted to a two-compartment model with t1/2? 0.25 h and t1/2? 6.86 h, respectively. Following oral administration, ellagic acid was detected in all examined tissues including kidney, liver, heart, lung and brain et al., and the highest levels were found in kidney and liver. PMID:25412040

Yan, Linlin; Yin, Peipei; Ma, Chao; Liu, Yujun

2014-01-01

38

Identification and quantitation of new glutamic acid derivatives in soy sauce by UPLC/MS/MS.  

PubMed

Glutamic acid is an abundant amino acid that lends a characteristic umami taste to foods. In fermented foods, glutamic acid can be found as a free amino acid formed by proteolysis or as a non-proteolytic derivative formed by microorganisms. The aim of the present study was to identify different structures of glutamic acid derivatives in a typical fermented protein-based food product, soy sauce. An acidic fraction was prepared with anion-exchange solid-phase extraction (SPE) and analyzed by UPLC/MS/MS and UPLC/TOF-MS. ?-Glutamyl, ?-glutamyl, and pyroglutamyl dipeptides, as well as lactoyl amino acids, were identified in the acidic fraction of soy sauce. They were chemically synthesized for confirmation of their occurrence and quantified in the selected reaction monitoring (SRM) mode. Pyroglutamyl dipeptides accounted for 770?mg/kg of soy sauce, followed by lactoyl amino acids (135?mg/kg) and ?-glutamyl dipeptides (70?mg/kg). In addition, N-succinoylglutamic acid was identified for the first time in food as a minor compound in soy sauce (5?mg/kg). PMID:24130027

Frerot, Eric; Chen, Ting

2013-10-01

39

UPLC-MS/MS determination in blood of a mixed-drug fatal intoxication: a case report.  

PubMed

Trends in forensic toxicology show the introduction of rapid analytical methods for the simultaneous quantitative analysis of drugs. The authors present a fatal case involving a 32-year-old male, found dead in bed by his mother, with several blue, white and orange pills next to the body. Empty tablets were found in the trash bin and a suicide note was on the desk. He was diagnosed with bipolar disorder and had been under psychiatric treatment, having repeatedly demonstrated intent to commit suicide. A rapid method was developed to determine 55 different medicines and 32 benzodiazepines in blood by ultra-performance liquid chromatography (UPLC) coupled with tandem mass spectrometry (MS/MS) with electrospray ionization source in positive and negative ion mode. Chromatographic analysis was preceded by an optimized solid-phase extraction procedure using Oasis() HLB (3 cc, 60 mg) extraction columns. The extracted analytes were separated by UPLC (Waters) with a reversed-phase Acquity UPLC() HSS T3 (2.1100 mm id, 1.8 ?m) column with acetonitrile and 0.1% formic acid in water as mobile phase, at 0.5 mL/min flow rate and a chromatographic run-time of 8 min. Analytes detection was achieved with a triple-quadrupole mass spectrometer in positive and negative electrospray ionization mode with multiple reaction monitoring (MRM). Two MRM transitions were monitored for each target-compound and one for each deuterated internal standards. Toxicological results showed high blood concentrations of antipsychotics (haloperidol, olanzapine and quetiapine), antidepressants (fluoxetine and paroxetine) and anxiolytics (bromazepam and lorazepam). Risperidone and other benzodiazepines were also present in therapeutic concentrations. Neither alcohol nor illicit drugs were present in the analyzed samples. The UPLC-MS-MS method showed to be appropriate for screening, identification and quantitation of antipsychotics, antidepressants, anxiolytics and antiepileptic drugs in blood after intake of therapeutic as well as toxic doses. The autopsy and toxicological results led the pathologist to rule that death was due to a mixed-drug intoxication. The manner of death was determined to be suicide. PMID:23159339

Proena, Paula; Franco, Joo Miguel; Mustra, Carla; Monteiro, Carla; Costa, Joana; Corte-Real, Francisco; Vieira, Duarte Nuno

2013-04-10

40

Partial least-squares-discriminant analysis differentiating Chinese wolfberries by UPLC-MS and flow injection mass spectrometric (FIMS) fingerprints.  

PubMed

Lycium barbarum L. fruits (Chinese wolfberries) were differentiated for their cultivation locations and the cultivars by ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS) and flow injection mass spectrometric (FIMS) fingerprinting techniques combined with chemometrics analyses. The partial least-squares-discriminant analysis (PLS-DA) was applied to the data projection and supervised learning with validation. The samples formed clusters in the projected data. The prediction accuracies by PLS-DA with bootstrapped Latin partition validation were greater than 90% for all models. The chemical profiles of Chinese wolfberries were also obtained. The differentiation techniques might be utilized for Chinese wolfberry authentication. PMID:25152955

Lu, Weiying; Jiang, Qianqian; Shi, Haiming; Niu, Yuge; Gao, Boyan; Yu, Liangli Lucy

2014-09-17

41

A reversed-phase capillary ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method for comprehensive top-down/bottom-up lipid profiling  

PubMed Central

Lipidomics is a critical part of metabolomics and aims to study all the lipids within a living system. We present here the development and evaluation of a sensitive capillary UPLC-MS method for comprehensive top-down/bottom-up lipid profiling. Three different stationary phases were evaluated in terms of peak capacity, linearity, reproducibility, and limit of quantification (LOQ) using a mixture of lipid standards representative of the lipidome. The relative standard deviations of the retention times and peak abundances of the lipid standards were 0.29% and 7.7%, respectively, when using the optimized method. The linearity was acceptable at >0.99 over 3 orders of magnitude, and the LOQs were sub-fmol. To demonstrate the performance of the method in the analysis of complex samples, we analyzed lipids extracted from a human cell line, rat plasma, and a model human skin tissue, identifying 446, 444, and 370 unique lipids, respectively. Overall, the method provided either higher coverage of the lipidome, greater measurement sensitivity, or both, when compared to other approaches of global, untargeted lipid profiling based on chromatography coupled with MS. PMID:22354571

Gao, Xiaoli; Zhang, Qibin; Meng, Da; Issac, Giorgis; Zhao, Rui; Fillmore, Thomas L.; Chu, Rosey K.; Zhou, Jianying; Tang, Keqi; Hu, Zeping; Moore, Ronald J.; Smith, Richard D.; Katze, Michael G.; Metz, Thomas O.

2012-01-01

42

A reversed-phase capillary ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) method for comprehensive top-down/bottom-up lipid profiling.  

PubMed

Lipidomics is a critical part of metabolomics and aims to study all the lipids within a living system. We present here the development and evaluation of a sensitive capillary UPLC-MS method for comprehensive top-down/bottom-up lipid profiling. Three different stationary phases were evaluated in terms of peak capacity, linearity, reproducibility, and limit of quantification (LOQ) using a mixture of lipid standards representative of the lipidome. The relative standard deviations of the retention times and peak abundances of the lipid standards were 0.29% and 7.7%, respectively, when using the optimized method. The linearity was acceptable at >0.99 over 3 orders of magnitude, and the LOQs were sub-fmol. To demonstrate the performance of the method in the analysis of complex samples, we analyzed lipids extracted from a human cell line, rat plasma, and a model human skin tissue, identifying 446, 444, and 370 unique lipids, respectively. Overall, the method provided either higher coverage of the lipidome, greater measurement sensitivity, or both, when compared to other approaches of global, untargeted lipid profiling based on chromatography coupled with MS. PMID:22354571

Gao, Xiaoli; Zhang, Qibin; Meng, Da; Isaac, Giorgis; Zhao, Rui; Fillmore, Thomas L; Chu, Rosey K; Zhou, Jianying; Tang, Keqi; Hu, Zeping; Moore, Ronald J; Smith, Richard D; Katze, Michael G; Metz, Thomas O

2012-03-01

43

Separation and Quantitation of Three Acidic Herbicide Residues in Tobacco and Soil by Dispersive Solid-Phase Extraction and UPLC-MS/MS.  

PubMed

A method for the determination of three acidic herbicides, dicamba, 2,4-dichlorophenoxyacetic acid (2,4-D) and 2,4,5-trichlorophenoxyacetic acid (2,4,5-T) in tobacco and soil has been developed based on the use of liquid-liquid extraction and dispersive solid-phase extraction (dispersive-SPE) followed by UPLC-MS/MS. Two percentage of (v/v) formic acid in acetonitrile as the extraction helped partitioning of analytes into the acetonitrile phase. The extract was then cleaned up by dispersive-SPE using primary secondary amine as selective sorbents. Quantitative analysis was done in the multiple-reaction monitoring mode using stable isotope-labeled internal standards for each compound. A separate internal standard for each analyte is required to minimize sample matrix effects on each analyte, which can lead to poor analyte recoveries and decreases in method accuracy and precision. The total analysis time was <4 min. The linear range of the method was from 1 to 100 ng mL(-1) with a limit of detection of each herbicide varied from 0.012 to 0.126 ng g(-1). The proposed method is faster, more sensitive and selective than the traditional methods and more accurate and robust than the published LC-MS/MS methods. PMID:24366907

Xiong, Wei; Tao, Xiaoqiu; Pang, Su; Yang, Xue; Tang, GangLing; Bian, Zhaoyang

2014-11-01

44

Simultaneous determination by UPLC-MS/MS of seven bioactive compounds in rat plasma after oral administration of Ginkgo biloba tablets: application to a pharmacokinetic study*  

PubMed Central

A rapid, reliable, and sensitive method was developed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with an electrospray ionization (ESI) source for determination of seven bioactive compounds in rat plasma after oral administration of Ginkgo biloba tablets (GBTs). The method simultaneously detects bilobalide (BB), ginkgolide A (GA), ginkgolide B (GB), ginkgolide C (GC), quercetin (QCT), kaempferol (KMF), and isorhamnetin (ISR) for pharmacokinetic study. The analytes and internal standard (IS) were extracted from rat plasma by acetidin. An MS/MS detection was conducted using multiple reaction monitoring (MRM) and operating in the negative ionization mode. The calibration curve ranges were 5500, 5500, 2.5250, 1100, 1100, 1100, and 1100 ng/ml for BB, GA, GB, GC, QCT, KMF, and ISR, respectively. The mean recovery of the analytes ranged from 68.11% to 84.42%. The intra- and inter-day precisions were in the range of 2.33%9.86% and the accuracies were between 87.67% and 108.37%. The method was used successfully in a pharmacokinetic study of GBTs. The pharmacokinetic parameters of seven compounds were analyzed using a non-compartment model. Plasma concentrations of the seven compounds were determined up to 48 h after administration, and their pharmacokinetic parameters were in agreement with previous studies. PMID:25367786

Wang, Wen-ping; Liu, Na; Kang, Qian; Du, Pei-pei; Lan, Yi; Zhao, Bo-chen; Chen, Yan-yan; Zhang, Qing; Li, Hui; Zhang, Ye-wen; Wu, Qing

2014-01-01

45

Simultaneous determination by UPLC-MS/MS of seven bioactive compounds in rat plasma after oral administration of Ginkgo biloba tablets: application to a pharmacokinetic study.  

PubMed

A rapid, reliable, and sensitive method was developed using ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) with an electrospray ionization (ESI) source for determination of seven bioactive compounds in rat plasma after oral administration of Ginkgo biloba tablets (GBTs). The method simultaneously detects bilobalide (BB), ginkgolide A (GA), ginkgolide B (GB), ginkgolide C (GC), quercetin (QCT), kaempferol (KMF), and isorhamnetin (ISR) for pharmacokinetic study. The analytes and internal standard (IS) were extracted from rat plasma by acetidin. An MS/MS detection was conducted using multiple reaction monitoring (MRM) and operating in the negative ionization mode. The calibration curve ranges were 5-500, 5-500, 2.5-250, 1-100, 1-100, 1-100, and 1-100 ng/ml for BB, GA, GB, GC, QCT, KMF, and ISR, respectively. The mean recovery of the analytes ranged from 68.11% to 84.42%. The intra- and inter-day precisions were in the range of 2.33%-9.86% and the accuracies were between 87.67% and 108.37%. The method was used successfully in a pharmacokinetic study of GBTs. The pharmacokinetic parameters of seven compounds were analyzed using a non-compartment model. Plasma concentrations of the seven compounds were determined up to 48 h after administration, and their pharmacokinetic parameters were in agreement with previous studies. PMID:25367786

Wang, Wen-Ping; Liu, Na; Kang, Qian; Du, Pei-Pei; Lan, Yi; Zhao, Bo-Chen; Chen, Yan-Yan; Zhang, Qing; Li, Hui; Zhang, Ye-Wen; Wu, Qing

2014-11-01

46

Differentiating organically and conventionally grown oregano using ultraperformance liquid chromatography mass spectrometry (UPLC-MS), headspace gas chromatography with flame ionization detection (headspace-GC-FID), and flow injection mass spectrum (FIMS) fingerprints combined with multivariate data analysis.  

PubMed

Ultraperformance liquid chromatography mass spectrometry (UPLC-MS), flow injection mass spectrometry (FIMS), and headspace gas chromatography (headspace-GC) combined with multivariate data analysis techniques were examined and compared in differentiating organically grown oregano from that grown conventionally. It is the first time that headspace-GC fingerprinting technology is reported in differentiating organically and conventionally grown spice samples. The results also indicated that UPLC-MS, FIMS, and headspace-GC-FID fingerprints with OPLS-DA were able to effectively distinguish oreganos under different growing conditions, whereas with PCA, only FIMS fingerprint could differentiate the organically and conventionally grown oregano samples. UPLC fingerprinting provided detailed information about the chemical composition of oregano with a longer analysis time, whereas FIMS finished a sample analysis within 1 min. On the other hand, headspace GC-FID fingerprinting required no sample pretreatment, suggesting its potential as a high-throughput method in distinguishing organically and conventionally grown oregano samples. In addition, chemical components in oregano were identified by their molecular weight using QTOF-MS and headspace-GC-MS. PMID:25050447

Gao, Boyan; Qin, Fang; Ding, Tingting; Chen, Yineng; Lu, Weiying; Yu, Liangli Lucy

2014-08-13

47

[Simultaneous determination of 9 major components of dachengqi tang in rat plasma by UPLC-MS/MS].  

PubMed

The study established a UPLC-MS/MS method that is used for simultaneous determination nine major bioactive compounds of Dachengqi Tang in rat plasma. Using Aglient C18 column (2.1 mm x 50 mm,1.7 microm) was chromatographed, using methanol-5 mmol x L(-1) ammonium formate mobile phase gradient, elution 0.3 mL x min(-1). In the plasma pre-treatment process, not only the method of methanol and acetonitrile protein precipitation was investigated, and different factors extraction solvent, the type of the scroll time, the number and the type of extraction solvent, the extraction volume of the extraction solution of liquid-liquid extraction is investigated. Finally, with ibuprofen as an internal standard, using ethyl acetate liquid-liquid extraction method pretreatment blood, N2 dry reconstituted supernatant after centrifugation UPLC-MS/MS analysis, in electrospray ionization (ESI) negative mode, using multiple reaction monitoring mode for testing. The linear range of emodin, rhein, aloe-emodin, chrysophanol, magnolol, honokiol, hesperidin and hesperitin is 0.33-660, 0.40-792, 0.41-827, 0.34-680, 0.45-907, 0.46-927, 0.43-867, 0.34-683, 0.39-787 microg x L(-1) respectively, good linear relationship; and extraction recovery were greater than 69.39%, days after the day of the RSD is less than 15%. This method can be used to study the rat gastric large bearing gas after Dachengqi Tang, the simultaneous determination of nine components in plasma for its pharmacokinetics and efficacy material base to provide a theoretical basis. PMID:25244773

Shen, Feng-Yun; Wei, Hui-Zhen; Sun, Yong-Bing; Wang, Yue-Sheng; Lv, Shang; Gao, Meng; Zeng, Lian-Qing; Rao, Yi

2014-06-01

48

Quantitative Determination of Levonorgestrel in Fish Plasma using UPLC-MS/MS  

EPA Science Inventory

In this study, a sensitive high-performance liquid chromatography electrospray tandem mass spectrometric method was developed for the determination of levonorgestrel in fish plasma using levonorgestrel-d6 as an internal standard (IS). In the laboratory, the fish cunner, (Tautogol...

49

Simultaneous determination of phenolic acids by UPLC-MS/MS in rat plasma and its application in pharmacokinetic study after oral administration of Flos Lonicerae preparations.  

PubMed

The current study aims to investigate the pharmacokinetic study of five phenolic acids (neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid) following oral administration of Flos Lonicerae preparations in rats. A rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to simultaneously determine the five phenolic acids in rat plasma. After mixing with the internal standard (IS) tinidazole, plasma samples were pretreated by liquid-liquid extraction with ethyl acetate/n-hexane (9:1, v/v). The separation was performed on an Acquity UPLC BEH C18 column (100mm2.1mm, 1.7?m) at a flow rate of 0.4mlmin(-1), and acetonitrile/methanol (4:1, v/v)-0.4% formic acid was used as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization (ESI) source with positive ionization mode. All calibration curves had good linearity (r>0.991) over the concentration ranges of 0.74-378ngml(-1) for neochlorogenic acid, 0.50-1030ngml(-1) for chlorogenic acid, 1.9-250ngml(-1) for cryptochlorogenic acid, 0.74-380ngml(-1) for 3,5-dicaffeoylquinic acid, and 5.1-328ngml(-1) for 3,4-dicaffeoylquinic acid. The intra-and inter-day precision were within 15% and the accuracy ranged from 86.2% to 114.1%. PMID:24004636

Zhou, Wei; Liu, Shijia; Ju, Wenzheng; Shan, Jinjun; Meng, Minxin; Cai, Baochang; Di, Liuqing

2013-12-01

50

Analysis of 21-hydroxy deflazacort in human plasma by UPLC-MS/MS: application to a bioequivalence study in healthy volunteers.  

PubMed

A sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometric (UPLC-MS/MS) method has been developed for the determination of 21-hydroxy deflazacort in human plasma using betamethasone as the internal standard (IS). After solid-phase extraction from 100 ?L human plasma, the analyte and IS were analyzed on Waters Acquity UPLC BEH C18 (50 mm 2.1 mm, 1.7 ?m) column using acetonitrile-4.0mM ammonium formate, pH 3.5 (90:10, v/v) as the mobile phase. The protonated analyte was quantified by selected reaction monitoring in the positive ionization mode by triple quadrupole mass spectrometer. The calibration plots were linear over the concentration range 0.50-500 ng/mL. Intra-batch and inter-batch precision (% CV) and accuracy (%) for five quality control samples ranged within 1.40-4.82% and 98.0-102.0% respectively. The overall mean extraction recovery of 21-hydroxy deflazacort from plasma ranged from 95.3 to 97.3%. Matrix effect was assessed by post-column analyte infusion and the extraction recovery was >95.0% across four quality control levels for the analyte and IS. Stability was evaluated under different conditions like bench top, autosampler, processed sample (at room temperature and in cooling chamber), freeze-thaw and long term stability. The method was applied to support a bioequivalence study of 30 mg deflazacort tablet formulation in 28 healthy subjects. Assay reproducibility was demonstrated by reanalysis of 115 incurred samples. PMID:23973630

Patel, Daxesh P; Sharma, Primal; Patel, Bhargav M; Sanyal, Mallika; Singhal, Puran; Shrivastav, Pranav S

2013-11-01

51

Analysis of water-soluble azo dyes in soft drinks by high resolution UPLC-MS  

Microsoft Academic Search

An UPLC-Orbitrap MS system was exploited to develop and validate a method for the simultaneous determination of 11 water-soluble azo dyes (Acid Yellow 17, Acid Red 14, Acid Red 26, Acid Red 73, Acid Orange 52, Acid Orange 7, Acid Orange 12, Acid Yellow 36, Acid Orange 5, Acid Red 88, and Acid Red 9) in soft drinks. Three pairs

X Liu; J. H. Li; X. L. Li; X. Y. Lu; J. Z. Shen; Y. W. Wang; Z. H. Zhang

2011-01-01

52

Analysis of water-soluble azo dyes in soft drinks by high resolution UPLCMS  

Microsoft Academic Search

An UPLCOrbitrap MS system was exploited to develop and validate a method for the simultaneous determination of 11 water-soluble azo dyes (Acid Yellow 17, Acid Red 14, Acid Red 26, Acid Red 73, Acid Orange 52, Acid Orange 7, Acid Orange 12, Acid Yellow 36, Acid Orange 5, Acid Red 88 and Acid Red 9) in soft drinks. Three pairs

X. Liu; J. L. Yang; J. H. Li; X. L. Li; X. Y. Lu; J. Z. Shen; Y. W. Wang; Z. H. Zhang

2011-01-01

53

Rapid quantification of 14 saponins of Maesa lanceolata by UPLC-MS/MS.  

PubMed

Saponins are high molecular weight glycosides which are known for their broad range of biological activities. In case of Maesa lanceolata, a tree growing in African countries, the maesasaponins showed virucidal, haemolytic, molluscicidal and anti-angiogenic activity. Since the different activities are dependent on the structure of the saponins, a method was developed and validated for the analysis of the individual saponins in this plant. Since the saponins were only present in small amounts, it was necessary to develop a very sensitive analytical method. For the fast and sensitive analysis of the extracted and purified plant samples ultra-performance liquid chromatography was coupled to a triple quadrupole mass spectrometer for MS/MS detection. A method in positive ESI mode, using sodium acetate in the mobile phase, was developed. The sodium adduct ion was selected as the precursor ion since it provided better sensitivity and a better, more stable fragmentation compared to the deprotonated and protonated ions. The intensity of the signal obtained by fragmentation of the sodium adducts of the saponins, was optimized by the addition of different concentrations of sodium acetate to the mobile phase. Reference standards were not available for all 14 saponins. Therefore, a relative MS/UV response was calculated allowing the estimation of the saponins in real samples. alpha-Hederin was used as external standard. The method was linear over the investigated concentration range with a good correlation coefficient (>0.99). The intra- and inter-day precisions were below 15% for most maesasaponins with the exception of maesasaponin II, which showed a precision within 20%. The recoveries of the spiked pure compounds maesasaponin IV.1 and VII.1 were 96.6% and 85.5%, respectively. The validated method can be applied in the investigation of the content of 14 saponins in transgenic and non-transgenic plant material of M. lanceolata. PMID:20441893

Foubert, K; Cuyckens, F; Vleeschouwer, K; Theunis, M; Vlietinck, A; Pieters, L; Apers, S

2010-06-15

54

Fast simultaneous determination of multiple water-soluble vitamins and vitamin-like compounds in infant formula by UPLC-MS\\/MS  

Microsoft Academic Search

Fortification of infant formula provides the sole source of nutrition for bottle-fed baby; therefore, particular attention should be paid to ensure an adequate and balanced intake of vitamins, which cannot be synthesized by the body, but essential for the normal growth and functioning of human body. An Ultra Performance LC-Tandem Mass Spectrometry (UPLC-MS\\/MS) method was developed for fast simultaneous determination

Hong Zhang; Si Chen; Wenjuan Liao; Yiping Ren

55

Pharmacokinetic properties of isorhamnetin, kaempferol and quercetin after oral gavage of total flavones of Hippophae rhamnoides L. in rats using a UPLCMS method  

Microsoft Academic Search

An ultra performance liquid chromatographymass spectrometric (UPLCMS) method was developed to investigate the pharmacokinetic properties of isorhamnetin, kaempferol and quercetin from a total flavone extract of Hippophae rhamnoides L. (TFH) after single dose oral administration. Rat plasma samples were pretreated using liquidliquid extraction, and chromatographic separation was performed on a C18 column using a linear gradient of methanol and formic

Guowen Li; Xiaoli Zeng; Yan Xie; Zhenzhen Cai; Jeffrey C. Moore; Xiurong Yuan; Zhihong Cheng; Guang Ji

56

Determination of rhynchophylline and hirsutine in rat plasma by UPLC-MS/MS after oral administration of Uncaria rhynchophylla extract.  

PubMed

An ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to concurrently determine rhynchophylline and hirsutine in rat plasma. The sample preparation of rat plasma was achieved by alkalization and liquid-liquid extraction. The mass transition of precursor ion???product ion pairs were monitored at m/z 385.2???160.0 for rhynchophylline, m/z 369.3???144.0 for hirsutine and m/z 414.0???220.0 for noscapine (internal standard). This method revealed linear relationships from 2.5 to 50?ng/mL (r(2) ?>?0.997) for rhynchophylline and from 2.5 to 50?ng/mL (r(2) ?>?0.998) for hirsutine. The limit of quantification values for rhynchophylline and hirsutine in rat plasma were both 2.5?ng/mL. Intra-day and inter-day precisions were within 10.6% and 12.5%, respectively, for rhynchophylline and hirsutine, and the accuracy (bias) was <10%. Liquid-liquid extraction of rat plasma samples resulted in insignificant matrix effect, and the extraction recoveries were >83.6% for rhynchophylline, 73.4% for hirsutine and 90.7% for the internal standard. This method was applied successfully to a pharmacokinetic study of rhynchophylline and hirsutine in rats after oral administration. PMID:24122787

Wu, Yu-Tse; Lin, Lie-Chwen; Tsai, Tung-Hu

2014-03-01

57

An UPLC-MS/MS method for separation and accurate quantification of tamoxifen and its metabolites isomers.  

PubMed

A selective and accurate analytical method is needed to quantify tamoxifen and its phase I metabolites in a prospective clinical protocol, for evaluation of pharmacokinetic parameters of tamoxifen and its metabolites in adjuvant treatment of breast cancer. The selectivity of the analytical method is a fundamental criteria to allow the quantification of the main active metabolites (Z)-isomers from (Z)'-isomers. An UPLC-MS/MS method was developed and validated for the quantification of (Z)-tamoxifen, (Z)-endoxifen, (E)-endoxifen, Z'-endoxifen, (Z)'-endoxifen, (Z)-4-hydroxytamoxifen, (Z)-4'-hydroxytamoxifen, N-desmethyl tamoxifen, and tamoxifen-N-oxide. The validation range was set between 0.5ng/mL and 125ng/mL for 4-hydroxytamoxifen and endoxifen isomers, and between 12.5ng/mL and 300ng/mL for tamoxifen, tamoxifen N-desmethyl and tamoxifen-N-oxide. The application to patient plasma samples was performed. PMID:25173109

Arellano, Ccile; Allal, Ben; Goubaa, Anwar; Roch, Henri; Chatelut, Etienne

2014-11-01

58

UPLC-MS/MS method for determination of selected pyrrolizidine alkaloids in feed.  

PubMed

Alkaloids known as secondary metabolites are grouped by typical structural characteristics into large families such as pyrrolizidine alkaloids (PAs) comprising more than 350 individual heterocyclic compounds. The PAs present a serious health risk to human and livestock; hence there is a need for methods that allow these dangerous plant toxins to be determined. In this study, a fast, reliable and sensitive approach is proposed to identify and quantify PAs in feed samples. PAs including monocrotaline, senkirkine, senecionine, seneciphylline and retrorsine were determined by ultra-performance liquid chromatography coupled with tandem mass spectrometry. Sample preparation was based on a modified QuEChERS approach. The mean recovery, precision, matrix effects and limits of quantification were assessed for three matrices within the method validation. The presented method was used to inspect 41 various feed samples, where the presence of PAs was expected. Roughages and feed for rabbits contained the highest levels of PAs, in general. PMID:25306344

Bolechov, Martina; Cslavsk, Josef; Pospchalov, Markta; Kosubov, Petra

2015-03-01

59

Simultaneous determination of four alkaloids in Solanum lyratum Thunb by UPLC-MS/MS method.  

PubMed

Four alkaloids, strychnine, soladulcidine, solamargine and (3-O-beta-D-glucopyranosyl-(1 --> 2)beta-D-glucopyranosyl-(1 --> 4)-beta-D-galactopyranoside-(25xi)-solanidan-3beta,23beta-diol)(abbreviation, glycoalkaloid A) were isolated from Solanum lyratum Thunb. The structures were elucidated by NMR and measuring physicochemical properties. Then a novel and rapid method using an ultra-performance liquid chromatography coupled with mass spectrometry was developed and validated for the simultaneous determination of these compounds. An acquit UPLC BEH C18 column (2.1 mm x 50 mm, 1.7 microm) was used. Acetonitrile and 0.1% formic acid were adopted as mobile phase. Detection was performed on a Waters Micromass Quattro Premier tandem quadrupole mass spectrometer in the positive ion mode using an electrospray source. The multiple reaction monitoring (MRM) mode was used to detect the target compounds. The established method showed a good linearity (R2 > 0.999 0) over the investigated concentration ranges, good inter-day and intra-day precisions (less than 2%) and good recoveries (from 99.8% to 100.1%) for all four target compounds. Compared to previous methods employing conventional high performance liquid chromatography (HPLC) separation, the ultra-high-pressure liquid chromatography-tandem mass spectrometry achieved preferable chromatographic parameters and significantly increased sample throughput. PMID:22512079

Jia, Yu-Rong; Tian, Xiao-Ling; Liu, Kai; Chen, Chen; Wang, Xiang-Lin; Zhang, Chen-Chen; Sun, Li-Xin

2012-02-01

60

Development of a UPLC-MS/MS bioanalytical method for the pharmacokinetic study of (-)-epiafzelechin, a flavan-3-ol with osteoprotective activity, in C57BL/6J mice.  

PubMed

(-)-Epiafzelechin is a flavan-3-ol commonly found in plant source. Biological studies suggested that (-)-epiafzelechin may have anti-inflammatory, anti-oxidant and bone-protective effect. However, it's in vivo efficacy remains to be demonstrated. A specific detection method for (-)-epiafzelechin was successfully developed by using UPLC-MS/MS to quantify the amount of (-)-epiafzelechin present in mice plasma after a liquid-liquid extraction by ethyl acetate. The separation was achieved by using a reversed-phase C18 column with a 16 min gradient elution protocol consisting of water (0.1%, v/v, formic acid) and 0-70% ACN (0.1%, v/v, formic acid). The lower limit of quantitation for (-)-epiafzelechin was found to be 12.5 ng/mL. This method exhibited a good linearity (r(2)=0.992). The intra-day and inter-day precision were within 12%, while the accuracy was between 97.6 and 113. 4%. A quantity of 10mg/kg synthetic (-)-epiafzelechin was administered to C57BL/6J mice by intravenous (i.v.) and intraperitoneal (i.p.) injections and the blood was collected at different time points. The plasma was then analyzed by the UPLC-MS/MS method, and the plasma drug concentration-time curves for i.v. and i.p. (-)-epiafzelechin injection were constructed. The maximum concentrations (Cmax) of (-)-epiafzelechin in blood by i.v. and i.p. injection were found to be 10.6 and 6.0 ?g/mL, respectively, while the time for reaching Cmax in i.p. injection was found to be 15 min. The distribution half-lives of (-)-epiafzelechin after i.v. and i.p. injection were found to be 7.0 and 12.6 min, respectively. Some of the PK parameters were found to be similar in both i.v. and i.p. injections of (-)-epiafzelechin owing to its high solubility in water. PMID:25108364

Wong, Ka Chun; Law, Man Chun; Wong, Man Sau; Chan, Tak Hang

2014-09-15

61

Development and validation of a UPLC-MS/MS method for quantification of SKLB010, an investigational anti-inflammatory compound, and its application to pharmacokinetic studies in beagle dogs.  

PubMed

SKLB010 is currently under development as a potential therapeutic agent for the treatment of acute hepatitis and rheumatoid arthritis. The purpose of this paper was to investigate the pre-clinical pharmacokinetics of SKLB010 in beagle dogs. An ultra performance liquid chromatographic tandem mass spectroscopy (UPLC-MS/MS) method was developed and validated for the quantitative determination of SKLB010 in dog plasma, using rosiglitazone as the internal standard (I.S.). Plasma samples were prepared by a simple solid phase extraction (SPE) method. The analyte and internal standard were separated by an Acquity UPLC BEH C18 (2.1 mm 50 mm) column with a mobile phase of methanol-water (80/20, v/v) over 2 min. Detection was based on the multiple reaction monitoring with the precursor-to-product ion transitions m/z 234.10?147.92 (SKLB010) and m/z 356.15?150.00 (I.S.). The method was validated according to FDA guidelines on bio-analytical method validation. The selectivity, sensitivity, linearity, accuracy, precision, extraction recovery, ion suppression and stability were within the acceptable ranges. The method described above was successfully applied to reveal the single- and multi-pharmacokinetic profiles of SKLB010 in beagle dogs and should be extendable to pharmacokinetic studies in other species as well. PMID:21680128

Ye, Xia; Tang, Minghai; Liu, Juan; Wang, Xianhuo; Ma, Liang; Zheng, Hao; Hu, Jia; Chen, Xiang; Duan, Xingmei; Chen, Lijuan

2011-09-10

62

Validation of a fast method for quantitative analysis of elvitegravir, raltegravir, maraviroc, etravirine, tenofovir, boceprevir and 10 other antiretroviral agents in human plasma samples with a new UPLC-MS/MS technology.  

PubMed

Therapeutic drug monitoring (TDM) of antiretrovirals requires accurate and precise analysis of plasma drug concentrations. This work describes a simple, fast and sensitive UPLC-MS/MS method for determination of the commonly used protease inhibitors such as amprenavir, atazanavir, darunavir, indinavir, lopinavir, ritonavir, saquinavir and tipranavir, tenofovir a nucleoside reverse transcriptase inhibitor (NRTI), the non-NRTI such as efavirenz, nevirapine, etravirine, the CCR5 antagonist maraviroc as well as the more recent antiretrovirals, the integrase inhibitors such as raltegravir, elvitegravir and the new direct acting anti-HCV boceprevir. Adapted deuterated internal standard was added to plasma aliquots (100?l) prior to protein precipitation with methanol and acetonitrile. This method employed ultra-performance liquid chromatography coupled to tandem mass spectrometry with electrospray ionization mode. All compounds eluted within 4.2-min run time. Calibration curves were validated, with correlation coefficients (r(2)) higher than 0.997, for analysis of therapeutic concentrations reported in the literature. Inter- and intra-assay variations were <15%. Evaluation of accuracy shows a deviation <15% from target concentration at each quality control level. No significant matrix effect was observed for any of the antiretroviral studied. This new validated method fulfills all criteria for TDM of 15 antiretrovirals and boceprevir drugs and was successfully applied in routine TDM of antiretrovirals. PMID:23995753

Djerada, Zoubir; Feliu, Catherine; Tournois, Claire; Vautier, Damien; Binet, Laurent; Robinet, Arnaud; Marty, Hlne; Gozalo, Claire; Lamiable, Denis; Millart, Herv

2013-12-01

63

Identification and quantitation of cocaine, benzoylecgonine, and cocaethylene in blood, serum, and plasma using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS).  

PubMed

Cocaine is a widely abused stimulant. Numerous methods exist for the identification of the drug, or more commonly, one of its metabolites in urine. Urine testing is useful for most cases, but it is necessary to use other matrices in forensic situations and when subjects are anuric. We describe a novel method for the analysis of cocaine, benzoylecgonine, and cocaethylene in blood, serum, and plasma utilizing ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Sample preparation has been minimized to a simple deproteinization step in which each specimen is mixed with an acetonitrile-internal standard mixture. The method has excellent precision across the linear range of 25-2,000 ng/mL for each analyte. With a run-time of 4 min, this method provides a significant improvement over traditional GC/MS methods. PMID:20077068

Kriger, Scott; Gunn, Josh; Terrell, Andrea R

2010-01-01

64

Development and validation of methods for the extraction of phenolic acids from plasma, urine, and liver and analysis by UPLC-MS.  

PubMed

This study developed and validated a method for the extraction and determination of 11 phenolic acids in rat plasma, urine, and liver by ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). A system suitability test (instrumental linearity, area, and retention time precision) was performed and recovery, intraday and between-day precisions, detection limits (LOD), and quantification limits (LOQ) were determined for all compounds in each biological matrix. Recoveries varied between 88 and 117% in plasma, between 87 and 102% in urine, and between 38 and 100% in liver. Precision was higher than 13.7% intraday and 14.0% interday in all matrices, at three concentration levels. To demonstrate the applicability, the method was used to estimate the concentrations of phenolic acids in samples from animals that received 5-caffeoylquinic acid (5-CQA) by gavage. The excellent validation results and the applicability of the method to real samples confirmed the suitability for studies on absorption, bioavailability, and pharmacokinetics of phenolic acids derived from foods rich in phenolic compounds. PMID:23711305

de Oliveira, Daniela M; Pinto, Carolina B; Sampaio, Geni R; Yonekura, Lina; Catharino, Rodrigo R; Bastos, Deborah H M

2013-06-26

65

Analysis of ecologically relevant pharmaceuticals in wastewater and surface water using selective solid phase extraction and UPLC/MS/MS  

EPA Science Inventory

A rapid and sensitive method has been developed for the analysis of 48 human prescription active pharmaceutical ingredients (APIs) and 6 metabolites of interest, utilizing selective solid-phase extraction (SPE) and ultra performance liquid chromatography in combination with tripl...

66

Validation and application of an UPLC-MS/MS method for the quantification of synthetic cannabinoids in urine samples and analysis of seized materials from the Portuguese market.  

PubMed

An UPLC-MS/MS method using ESI+ionization and MRM was developed and fully validated according to international guidelines for the qualitative and quantitative analysis of nine synthetic cannabinoids and/or their metabolites in urine samples (1mL). Prior to extraction the samples were subjected to an enzymatic hydrolysis using ?-glucuronidase followed by a SPE procedure using Oasis() HLB 3cc (60mg) columns. The chromatographic separation was performed with an Acquity UPLC() HSS T3 (50mm2.1mm i.d., 1.8?m) reversed-phase column using a gradient with methanol-ammonium formate 2mM (0.1% formic acid) and with a run time of 9.5min. The method was validated in terms of selectivity, capacity of identification, limits of detection (0.01-0.5ng/mL) and quantification (0.05-0.5ng/mL), recovery (58-105%), carryover, matrix effect, linearity (0.05-50ng/mL), intra-assay precision, inter-assay accuracy and precision (CV<20%). The method was applied to 80 authentic samples, five of them (6.2%) were confirmed or suspected to be positive for the metabolites JWH-018 N-hydroxypentyl and JWH-018 N-pentanoic acid of JWH-018 and for the metabolite JWH-122 N-(5-hydroxypentyl) of JWH-122, and three of them in association with THC and/or THCCOOH (substances included in the method, together with the 11-OH-THC). Additionally, 17 spice products were analyzed, for which were confirmed the presence of the following substances: AM-2201, JWH-018, JWH-022 JWH-073, JWH-122, JWH-203, JWH-210, JWH-250, HU-210 and RCS-4, according to the comparison with authentic reference material and published data. The analytical method developed allowed the analysis of synthetic cannabinoids and the notification of the first cases in Portugal. PMID:25127518

Simes, Susana Sadler; Silva, Ins; Ajenjo, Antonio Castaera; Dias, Mrio Joo

2014-10-01

67

Pharmacokinetics difference of multiple active constituents from decoction and maceration of Fuzi Xiexin Tang after oral administration in rat by UPLC-MS/MS.  

PubMed

Fuzi Xiexin Tang (FXT) is a classic traditional Chinese medicine formula which has been employed in clinical for more than 1800 years. The distinctive preparation method (maceration) recorded in ancient time is different from one in modern clinical practice (decoction). Aim of this study is to investigate the pharmacokinetic difference of alkaloids, flavones and anthraquinones in rats after oral administration of decoction of FXT (DFXT, 30gkg(-1)), maceration of FXT (MFXT, 30gkg(-1)) and decoction of Aconiti Lateralis Radix Preparata (DAR, 6gkg(-1)) by a validated UPLC-MS/MS method. Plasma concentrations and pharmacokinetic parameters of 16 active constituents (aconitine, hypaconitine, mesaconitine, benzoylaconine, benzoylhypaconine, benzoylmesaconine, berberine, palmatine, jatrorrhizine, coptisine, baicalin, wogonin, wogonoside, emodin, aloe-emodin, rhein) in rat were quantified and compared. Different preparative methods resulted in significant difference on exposure and pharmacokinetic characteristics of alkaloids, flavones and anthraquinones from FXT, especially protoberberine alkaloids. Concentrations of monoester-diterpenoid alkaloids were below the LOD in rat plasma after administration of DFXT and MFXT because of the existence of other three herbs from FXT. Maceration could decrease the absorption of flavones while increased the absorption of anthraquinones. Cmax of emodin and rhein were 3.1 and 10.3 times increased, while eliminations of these two constituents were 8.0 and 19.0 times slower after administration of MFXT. Bioavailability of both flavones and anthraquinones increased after administration of MFXT, especially emodin and rhein increasing as much as 13.5 and 20.7 times. Herb-herb interaction between DAR and other three herbs from FXT significantly influenced the exposure of aconitum alkaloids. PMID:24469098

Zhang, Qian; Ma, Yue-ming; Wang, Zheng-tao; Wang, Chang-hong

2014-04-01

68

Simultaneous determination of 12 illicit drugs in whole blood and urine by solid phase extraction and UPLC-MS/MS.  

PubMed

A rapid and sensitive method based on solid phase extraction and ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) for the simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylene-dioxymethamphetamine, N-methyl-1-(3,4-methyl-enedioxyphenyl)-2-butanamine, 3,4-methylenedioxyethylamphetamine, p-methoxymethamphetamine, ephedrine, N-methylephedrine, cathinone, methcathinone, and ketamine in whole blood and urine was developed and validated. Following solid phase extraction, the analytes were separated on ACQUITY UPLC BEH Phenyl column (100mm2.1mm, 1.7?m) under gradient elution using a mobile phase containing of acetonitrile and 0.3% formic acid in water at a flow rate of 0.4mLmin(-1) and analyzed by a triplequadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode. The proposed method was linear for each analyte with correlation coefficients over 0.99. Recovery validation studies showed accuracy bias below 4.4%. Acceptable precision was also obtained with a relative standard deviation below 8.9%. The sensitivity of the assay was found to be adequate for the quantitation of the illicit drugs in whole blood and urine sample and was higher than reported methods. The present method was proved to be reliable and robust for drug screening in forensic toxicological analysis. PMID:24631805

Zhang, Lin; Wang, Zhao-Hong; Li, Hong; Liu, Yong; Zhao, Meng; Jiang, Ye; Zhao, Wen-Song

2014-04-01

69

Advantages of online SPE coupled with UPLC/MS/MS for determining the fate of pesticides and pharmaceutical compounds.  

PubMed

Laboratory experimentation is essential for our understanding of the fate and behaviour of pollutants. Many analytical techniques exist, but they all have disadvantages either in terms of sensitivity or of selectivity. The number of samples that can be analysed, the low volume of samples available during the experiment and the need to identify different degradates are all obstacles that new techniques are able to overcome. The work presented here summarizes progress in the field of metrology as concerns online solid phase extraction technology coupled with liquid chromatography followed by tandem mass spectrometry detection. Recently developed analytical techniques were validated for both 18 pesticides and their degradates and 17 pharmaceuticals and their degradates. Limits of quantification from 20 to 70ngL(-1) for pharmaceuticals and from 15 to 25ngL(-1) for pesticides and metabolites have been obtained, with linearity range up to 1?gL(-1). The limits of quantification of a few nanograms per litre, the possibility of working on less than 1mL of sample and the simultaneous quantification of the target products and their transformation products are all advantages that are demonstrated by two environmental applications. The first application concerns the evaluation of ecotoxicological effects of pesticides on aquatic organisms exposed in mesocosms. The second application aims to determine the adsorption constants of pharmaceutical molecules on soils and river sediments. For both applications, the robustness, range of linearity and limit of quantification of the developed analytical methods satisfy the requirements for laboratory experiments conducted under controlled conditions. Specific constraints generated by this type of experiment (adding CaCl2 for the adsorption study and filtration of the water coming from the mesocosms) were not found to limit the use of online SPE. These two preliminary studies show that new experimental fields are possible thanks to online solid phase extraction coupled with liquid chromatography. PMID:23907687

Togola, Anne; Baran, Nicole; Coureau, Charlotte

2014-02-01

70

Development and validation of an UPLC-MS/MS method for the determination of ionophoric and synthetic coccidiostats in vegetables.  

PubMed

In poultry farming, anticoccidial drugs are widely used as feed additives for the prevention and treatment of coccidiosis. Because coccidiostats and veterinary medicines, in general, are often poorly absorbed, manure from treated animals may contain high concentrations of these compounds. Experimental studies have shown that the uptake of veterinary medicines by plants from soil containing contaminated manure may occur. This leads to several questions regarding the impact on the environment, resistance problems, and public health and allergy issues. This work describes the development of a quantification method for coccidiostats in vegetables. Vegetables were spiked at 100 ?g kg(-1) (dry weight) with coccidiostats (monensin, narasin, lasalocid A, salinomycin, diclazuril, and nicarbazin) in order to optimize the extraction and clean-up. Possible critical factors (e.g., extraction solvent) were statistically examined by linear regression with the use of Plackett-Burman and full factorial designs. Final extracts were analyzed with ultra-performance liquid chromatography tandem mass spectrometry operating in multiple-reaction monitoring mode. Both the synthetic and ionophoric coccidiostats could be determined in a single run with an analysis time of 5 min. The developed method was validated taking into account the requirements of the Commission Decision 2002/657/EC as a guideline. The method is regarded as applicable for its intended purposes with quantification limits between 0.30 and 2.98 ?g kg(-1). This method could be used to establish possible maximum residue limits for coccidiostats in vegetables, as already exist for eggs, meat, and milk. PMID:21984012

Broekaert, N; Van Peteghem, C; Daeseleire, E; Sticker, D; Van Poucke, C

2011-12-01

71

Simultaneous determination of caffeic acid derivatives by UPLC-MS/MS in rat plasma and its application in pharmacokinetic study after oral administration of Flos Lonicerae-Fructus Forsythiae herb combination.  

PubMed

The current study aims to investigate the pharmacokinetic study of eight caffeic acid derivatives (forsythoside A, isoforsythoside, forsythoside B, neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid) following oral administration of Flos Lonicerae-Fructus Forsythiae herb combination in rats. A rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine the eight caffeic acid derivatives simultaneously in rat plasma. After mixing with the internal standard (IS) tinidazole, plasma samples were pretreated by liquid-liquid extraction with n-butyl alcohol/ethyl acetate (7:3, v/v). The separation was performed on an Acquity UPLC HSS T3 C18 column (100mm2.1mm, 1.8?m) at a flow rate of 0.4mLmin(-1), and acetonitrile/methanol (4:1, v/v)-0.4% formic acid was used as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization (ESI) source with positive and negative ionization modes. All calibration curves had good linearity (r>0.991) over the concentration ranges of 1.097-2246ngmL(-1) for neochlorogenic acid, 6.535-6692ngmL(-1) for chlorogenic acid, 2.103-2153ngmL(-1) for cryptochlorogenic acid, 0.5058-129.5ngmL(-1) for 3,5-dicaffeoylquinic acid, 0.3205-82.05ngmL(-1) for 3,4-dicaffeoylquinic acid, 1.002-512.8ngmL(-1) for isoforsythoside, 0.4795-982.1ngmL(-1) for forsythoside A and 0.7587-776.9ngmL(-1) for forsythoside B, respectively. The intra- and inter-batch precisions were all within 15% and the accuracy (relative error, RE%) all ranged from 85.68% to 114.7%. It was shown from pharmacokinetic parameters that the rank order of AUC0-t, Cmax and T1/2k for phenolic acids was chlorogenic acid>neochlorogenic acid?cryptochlorogenic acid>3,4-dicaffeoylquinic acid?3,5-dicaffeoylquinic acid (most of them had significant differences), which corresponded to their administration dosages to rats, but that of MRT0-t and T1/2z were opposite. Besides, the AUC0-t, Cmax, MRT and T1/2z except T1/2k of isoforsythoside and forsythoside B had no significant difference, compared to that of forsythoside A though their administration dosages were significantly lower than that of forsythoside A. All results showed that the method was applied to the pharmacokinetic study of the eight caffeic acid derivatives in rat plasma successfully after oral administration of Flos Lonicerae-Fructus Forsythiae herb combination, and there were significant differences of caffeic acid derivatives even isomers in the pharmacokinetic parameters. PMID:24441018

Zhou, Wei; Shan, Jinjun; Wang, Shouquan; Ju, Wenzheng; Meng, Minxin; Cai, Baochang; Di, Liuqing

2014-02-15

72

Development of a high-throughput ultra performance liquid chromatography-mass spectrometry assay to profile 18 eicosanoids as exploratory biomarkers for atherosclerotic diseases.  

PubMed

Abundant evidence suggests a prominent role for eicosanoids and metabolites in the pathogenesis and prognosis of inflammatory diseases. A sensitive and high-throughput SPE UPLC-MS/MS method was developed to quantitatively interrogate the levels of 18 eicosanoids in human and monkey plasma samples. A limit of quantitation of 0.25ng/mL was achieved for all 18 investigated compounds with linear ranges spanning four orders of magnitude. Bioanalytical performance of this assay was fully characterized including SPE extraction efficiency, matrix effect, autosampler stability, benchtop stability and freeze-thaw cycle variability. Endogenous levels of the eicosanoids and analogs within a set of monkey plasma samples challenged with lipopolysaccharide and human plasma samples were quantified by this ultra performance liquid chromatography-mass spectrometry (UPLC-MS/MS) assay. Quantitative eicosanoid profiles of the human samples were further analyzed by a non-supervised cluster analysis, which revealed a set of potential positive and negative lipid biomarkers to distinguish the following three groups: healthy individuals, hypertensive patients and severe atherosclerosis patients. The components of the negative biomarker cluster (8-HETE, LTB4, 9-HODE and 13-HODE) are putative ligands of peroxisome proliferator-activated receptors (PPARs), a family of master genes controlling the resolution of inflammatory signaling. PMID:23973531

Rago, Brian; Fu, Cexiong

2013-10-01

73

High-Sensitivity Spectrophotometry.  

ERIC Educational Resources Information Center

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.

Harris, T. D.

1982-01-01

74

UPLC-MS/MS assay for the simultaneous quantification of carvedilol and its active metabolite 4'-hydroxyphenyl carvedilol in human plasma to support a bioequivalence study in healthy volunteers.  

PubMed

An ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed for the simultaneous determination of carvedilol and its pharmacologically active metabolite 4'-hydroxyphenyl carvedilol in human plasma using their deuterated internal standards (IS). Samples were prepared by solid-phase extraction using 100 ?L human plasma. Chromatographic separation of analytes was achieved on UPLC C18 (50 2.1 mm, 1.7 m) column using acetonitrile-4.0 mM ammonium formate, pH 3.0 adjusted with 0.1% formic acid (78:22, v/v) as the mobile phase. The multiple reaction monitoring transitions for both the analytes and IS were monitored in the positive electrospray ionization mode. The method was validated over a concentration range of 0.05-50 ng/mL for carvedilol and 0.01-10 ng/mL for 4'-hydroxyphenyl carvedilol. Intra- and inter-batch precision (% CV) and accuracy for the analytes varied from 0.74 to 3.88 and 96.4 to 103.3% respectively. Matrix effect was assessed by post-column analyte infusion and by calculation of precision values (coefficient of variation) in the measurement of the slope of calibration curves from eight plasma batches. The assay recovery was within 94-99% for both the analytes and IS. The method was successfully applied to support a bioequivalence study of 12.5 mg carvedilol tablets in 34 healthy subjects. PMID:23483571

Patel, Daxesh P; Sharma, Primal; Sanyal, Mallika; Singhal, Puran; Shrivastav, Pranav S

2013-08-01

75

Natural occurrence of fumonisins and ochratoxin A in some herbs and spices commercialized in Poland analyzed by UPLC-MS/MS method.  

PubMed

Unsanitary conditions during harvesting, drying, packing and storage stages in production and processing of spices and herbs could introduce mycotoxin contamination. The occurrence of ochratoxin A and fumonisins in popular spices and herbs was studied, using liquid chromatography-electrospray-mass spectrometry. Apart from mycotoxins, ergosterol as a factor indicating fungal development was also analysed. A total of 79 different samples commercialized in Poland were randomly purchased from popular markets were tested for mycotoxins. The frequency of samples with fumonisins was lower (31%) than ochratoxin A (49%). Free from mycotoxins were samples of bay leaf and white mustard. ERG content - in spice samples with high concentration level of mycotoxins - was also significantly higher than in samples with little to no mycotoxins. PMID:24010625

Wa?kiewicz, Agnieszka; Beszterda, Monika; Bocianowski, Jan; Goli?ski, Piotr

2013-12-01

76

Study of the ESI and APCI interfaces for the UPLC-MS/MS analysis of pesticides in traditional Chinese herbal medicine.  

PubMed

In this work, 53 selected pesticides of different chemical groups were extracted from Chinese herbal medicines and determined by ultra-high-performance liquid chromatography (UHPLC)-tandem mass spectrometry (MS/MS) using both electrospray ionization (ESI) and atmospheric-pressure chemical ionization (APCI). Extracts were obtained using the acetonitrile-based quick, easy, cheap, effective, rugged, and safe (QuEChERS) sample preparation technique. Cleanup was performed by dispersive solid-phase extraction using primary secondary amine, graphitized carbon black, and octadecylsilane. Two atmospheric-pressure interfaces, ESI and APCI, were checked and compared. The validation study, including detection limits, linearity, and matrix effects, was conducted on fritillaria, radix ginseng, folium isatidis, semen persicae, and flos lonicerae in multiple reaction monitoring mode. These matrices represent a variety of plants used in traditional Chinese medicine. Fritillaria and radix ginseng were chosen as representatives for roots, folium isatidis was chosen as a representative for leaves, semen persicae was chosen as a representative for seeds, and flos lonicerae was chosen as a representative for flowers. The limits of detection for pesticides were lower in the UHPLC-ESI-MS/MS method than in the UHPLC-APCI-MS/MS method. Matrix effects on the two ionizations were evaluated for the five matrices. Soft signal enhancement in UHPLC-APCI-MS/MS and signal suppression in UHPLC-ESI-MS/MS were observed. PMID:24346143

Chen, Lina; Song, Fengrui; Liu, Zhiqiang; Zheng, Zhong; Xing, Junpeng; Liu, Shuying

2014-02-01

77

High-Sensitivity Microwave Optics.  

ERIC Educational Resources Information Center

Describes a 3.33-cm wavelength (9 GHz) microwave system that achieves a high overall signal sensitivity and a well-collimated beam with moderate-size equipment. The system has been used to develop microwave versions of the Michelson interferometer, Bragg reflector, Brewster's law and total internal reflection, and Young's interference experiment.

Nunn, W. M., Jr.

1981-01-01

78

High sensitive airborne radioiodine monitor.  

PubMed

Airborne radioiodine monitoring includes a problem in that commercial radioactive gas monitors have inadequate sensitivity. To solve this problem, we designed a highly sensitive monitoring system. The higher counting efficiency and lower background made it possible to perform the low-level monitoring. The characteristics of the system were investigated using gaseous (125)I. The minimum detectable activity concentration was 1 10(-4)Bq cm(-3) for 1 min counting, which is one tenth of the legal limit for the radiation controlled areas in Japan. PMID:23602709

Ogata, Yoshimune; Yamasaki, Tadashi; Hanafusa, Ryuji

2013-11-01

79

High-sensitivity magnetoresistive transducers  

NASA Astrophysics Data System (ADS)

Magnetoresistive transducers, combined with appropriate signal conditioning, can be used to detect magnetic-field changes from small currents, geomagnetic anomalies, and perturbations in the earth's field from ferromagnetic objects. Two different designs of transducers are reported on-herringbone type, and barberpole biased type. Sensitivities as high as 3.5 mV/V/Oe have been obtained. The highest reported value seen in published literature is 1.75 mV/V/Oe (Philips Technical Publication 268), whereas values around 1.0 mV/V/Oe are typical. These high-sensitivity transducers are designed and fabricated based on previously published theoretical analysis [B. Pant, J. Appl. Phys. 67, 414 (1990)] of the response of thin magnetoresistive strips to external fields. This analysis indicates that to increase the sensitivity of these transducers one must reduce the ratio of strip thickness to its width and rotate the easy axis away from the long dimension of the strip wherever appropriate. The theoretical and experimental curves of bias field versus sensitivity for the herringbone design, and the transfer function for the barberpole design, are reported.

Pant, Bharat B.; Krahn, Donald R.

1991-04-01

80

A demonstration of the use of ultra-performance liquid chromatography-mass spectrometry [UPLC/MS] in the determination of amphetamine-type substances and ketamine for forensic and toxicological analysis.  

PubMed

We have recently seen the emergence of ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry as an alternative to traditional high-performance liquid chromatography techniques. The strengths of UPLC technology promote the ability to separate and identify drug compounds with significant gains in resolution and sensitivity and marked reductions in the overall time of analysis. As increased throughput is the desire of the practical toxicology laboratory, the aim of this study was to trial commercially available technology by assessment of the separation of several commonly encountered amphetamine-type substances. From injection of a poly-drug reference standard and whole blood extract, we successfully separated and identified amphetamine, methamphetamine, ephedrine, pseudoephedrine, phentermine, MDA, MDMA, MDEA and ketamine in less than 3 min using the Acquity UPLC-Micromass Quattro Micro API MS instrumentation (Waters Corporation, USA). In addition to this significant reduction in overall run time, all peaks exhibited acceptable resolution using selected ion recording (SIR), with analysis indicating the capability to separate 5-11 peaks in 1.75 min using the current system parameters. From this introductory data, it is therefore indicated that the technological advancements defining ultra-performance liquid chromatography will allow it to serve as a powerful analytical tool for rapid throughput analysis. PMID:16617037

Apollonio, Luigino G; Pianca, Dennis J; Whittall, Ian R; Maher, William A; Kyd, Jennelle M

2006-05-19

81

Sensitivities of High Energy Compounds  

Microsoft Academic Search

The article presents asurvey of the development trends in studies of sensitivity (initiation\\u000a reactivity) of energetic materials (EMs) over the last nine years, focusing mainly on impact and shock sensitivities.\\u000a Attention is given to the initiation by heat, laser, electrostatic discharge, impact and shock, including\\u000a the influence of hydrostatic compression, crystal defects, molecular structure and desensitizing admixtures\\u000a on the initiation

Svatopluk Zeman

82

High sensitivity RNA pseudoknot prediction  

PubMed Central

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. PMID:17179177

Huang, Xiaolu; Ali, Hesham

2007-01-01

83

Multi-drug and metabolite quantification in postmortem blood by liquid chromatography-high-resolution mass spectrometry: comparison with nominal mass technology.  

PubMed

High-resolution mass spectrometry (HRMS) is being applied in postmortem drug screening as an alternative to nominal mass spectrometry, and additional evaluation in quantitative casework is needed. We report quantitative analysis of benzoylecgonine, citalopram, cocaethylene, cocaine, codeine, dextromethorphan, dihydrocodeine, diphenhydramine, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine, hydrocodone, hydromorphone, meperidine, methadone, morphine, oxycodone and oxymorphone in postmortem blood by ultra-performance liquid chromatography (UPLC)-MS(E)/time-of-flight (TOF). The method employs analyte-matched deuterated internal standardization and MS(E) acquisition of precursor and product ions at low (6 eV) and ramped (10-40 eV) collision energies, respectively. Quantification was performed using precursor ion data obtained with a mass extraction window of 5 ppm. Fragment and residual precursor ion acquisitions at ramped collision energies were evaluated as additional analyte identifiers. Extraction recovery of >60% and matrix effect of <20% were determined for all analytes and internal standards. Defined limits of detection (10 ng/mL) and quantification (25 ng/mL) were validated along with a linearity analytical range of 25-3,000 ng/mL (R(2) > 0.99) for all analytes. Parallel UPLC-MS(E)/TOF and UPLC-MS/MS analysis showed comparable precision and bias along with concordance of 253 positive (y = 1.002x + 1.523; R(2) = 0.993) and 2,269 negative analyte findings in 159 postmortem cases. Analytical performance and correlation studies demonstrate accurate quantification by UPLC-MS(E)/TOF and extended application of HRMS in postmortem casework. PMID:25217537

Rosano, Thomas G; Na, Seo; Ihenetu, Kenneth; Swift, Thomas A; Wood, Michelle

2014-10-01

84

Cryogenic High-Sensitivity Magnetometer  

NASA Technical Reports Server (NTRS)

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.

Day, Peter; Chui, Talso; Goodstein, David

2005-01-01

85

Absolute quantification of UGT1A1 in various tissues and cell lines using isotope label-free UPLC-MS/MS method determines its turnover number and correlates with its glucuronidation activities.  

PubMed

Uridine 5'-diphosphate-glucuronosyltransferase (UGT)1A1 is a major phase II metabolism enzyme responsible for glucuronidation of drugs and endogenous compounds. The purpose of this study was to determine the expression level of UGT1A1 in human liver microsomes and human cell lines by using an isotope label-free LC-MS/MS method. A Waters Ultra performance liquid chromatography (UPLC) system coupled with an API 5500Qtrap mass spectrometer was used for the analysis. Two signature peptides (Pep-1, and Pep-2) were employed to quantify UGT1A1 by multiple reaction monitoring (MRM) approach. Standard addition method was used to validate the assay to account for the matrix effect. 17?-Estradiol was used as the marker substrate to determine UGT1A1 activities. The validated method has a linear range of 200-0.0195nM for both signature peptides. The precision, accuracy, and matrix effect were in acceptable ranges. UGT1A1 expression levels were then determined using 8 individual human liver microsomes, a pooled human liver microsomes, three UGT1A1 genotyped human liver microsomes, and four cell lines (Caco-2, MCF-7, Hela, and HepG2). The correlations study showed that the UGT1A1 protein levels were strongly correlated with its glucuronidation activities in human liver microsomes (R(2)=0.85) and in microsomes prepared from cell lines (R(2)=0.95). Isotope-labeled peptides were not necessary for LC-MS/MS quantitation of proteins. The isotope label-free absolute quantification method used here had good accuracy, sensitivity, linear range, and reproducibility, and were used successfully for the accurate determination of UGT1A1 from tissues and cell lines. PMID:24055854

Xu, Beibei; Gao, Song; Wu, Baojian; Yin, Taijun; Hu, Ming

2014-01-01

86

Capacitive transient detector of high sensitivity  

Microsoft Academic Search

A capacitive detector is described which displays high sensitivity and accuracy in the measurement of transients. The device has been used in an LC circuit for studies of third sound in thin helium films. When operated in a phase-lock mode at 21 MHz its observed sensitivity is 15 Hz per angstrom of helium film thickness; changes in average film thickness

F. M. Ellis; J. S. Brooks; R. B. Hallock

1981-01-01

87

High-throughput LC-MS/MS based simultaneous determination of polyamines including N-acetylated forms in human saliva and the diagnostic approach to breast cancer patients.  

PubMed

The determination of polyamines and their N-acetylated forms was performed by ultraperformance liquid chromatography coupled with tandem mass spectrometry (UPLC-MS/MS). The polyamines efficiently reacted with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) in 0.1 M borax (pH 9.3) at 60 C for 30 min. The resulting derivatives were analyzed by electrospray ionization (ESI)-MS and sensitively detected by selected reaction monitoring (SRM). Furthermore, a rapid separation of the polyamine derivatives within 10 min was performed by UPLC using an antipressurized column packed with 1.7-?m octadecylsilyl (ODS) silica gel. The limits of detection (S/N = 3) on the SRM chromatograms were at the attomole level (9-43 amol). This procedure was used to successfully determine 11 polyamines, including their N-acetylated forms, in the saliva of patients with primary and relapsed breast cancer and healthy volunteers. The level of several polyamines (Ac-PUT, Ac-SPD, Ac-SPM, DAc-SPD, and DAc-SPM) increases in breast cancer patients. Furthermore, the levels of three polyamines (Ac-SPM, DAc-SPD, and DAc-SPM) were significantly higher only in the relapsed patients. The present method proved highly sensitive and is characterized by specificity and feasibility for sample analysis. Consequently, the proposed method is useful for the noninvasive salivary diagnosis of cancer patients and could be applied to determine polyamines in several specimens of biological nature. PMID:24274257

Tsutsui, Haruhito; Mochizuki, Toshiki; Inoue, Koichi; Toyama, Tatsuya; Yoshimoto, Nobuyasu; Endo, Yumi; Todoroki, Kenichiro; Min, Jun Zhe; Toyo'oka, Toshimasa

2013-12-17

88

High Sensitivity deflection detection of nanowires  

SciTech Connect

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.

Sanii, Babak; Ashby, Paul

2009-10-28

89

High sensitivity optically pumped quantum magnetometer.  

PubMed

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 ?W and an operation temperature of 48C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327?fT/Hz() over a bandwidth of 26?Hz and that this sensitivity drops to 130?pT/Hz() 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. PMID:23766716

Tiporlini, Valentina; Alameh, Kamal

2013-01-01

90

High Sensitivity Optically Pumped Quantum Magnetometer  

PubMed Central

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??W and an operation temperature of 48C. Results show that the ultimate intrinsic sensitivity of the quantum magnetometer that can be achieved is 327?fT/Hz1/2 over a bandwidth of 26?Hz and that this sensitivity drops to 130?pT/Hz1/2 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. PMID:23766716

Tiporlini, Valentina; Alameh, Kamal

2013-01-01

91

Highly sensitive beam steering with plasmonic antenna  

NASA Astrophysics Data System (ADS)

In this work, we design and study a highly sensitive beam steering device that integrates a spiral plasmonic antenna with a subwavelength metallic waveguide. The short effective wavelength of the surface plasmon polaritons (SPPs) mode supported by the metallic waveguide is exploited to dramatically miniaturize the device and improve the sensitivity of the beam steering. Through introducing a tiny displacement of feed point with respect to the geometrical center of the spiral plasmonic antenna, the direction of the radiation can be steered at considerably high angles. Simulation results show that steering angles of 8, 17 and 34 are obtainable for a displacement of 50 nm, 100 nm and 200 nm, respectively. Benefiting from the reduced device size and the shorter SPP wavelength, the beam steering sensitivity of the beam steering is improved by 10-fold compared with the case reported previously. This miniature plasmonic beam steering device may find many potential applications in quantum optical information processing and integrated photonic circuits.

Rui, Guanghao; Zhan, Qiwen

2014-08-01

92

Highly sensitive submillimeter InSb photodetectors  

SciTech Connect

Submillimeter photoconductivity of the electron gas in bulk InSb has been studied. A new design of the InSb photodetector in the form of planar coils with a length-to-width ratio of two orders of magnitude is suggested. This design enables fabrication of highly sensitive photodetectors with the responsivity peak tunable by magnetic field.

Vasilyev, Yu. B., E-mail: yu.vasilyev@mail.ioffe.ru; Usikova, A. A.; Il'inskaya, N. D.; Petrov, P. V.; Ivanov, Yu. L. [Russian Academy of Sciences, Ioffe Physicotechnical Institute (Russian Federation)

2008-10-15

93

High blood pressure and visual sensitivity  

NASA Astrophysics Data System (ADS)

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.

Eisner, Alvin; Samples, John R.

2003-09-01

94

High sensitivity optical position sensitive detectors fabricated from high resistivity substrates  

Microsoft Academic Search

Position sensitive detectors (PSDs) comprise optical sensors used in applications such as robotic vision, machine tool alignment and other precision measurements. This paper will report on a series of Schottky Barrier crystalline silicon devices which display marked advantages including rapid response times, easier fabrication techniques and high sensitivities compared with most other research work now being concentrated on PECVD amorphous

J. Henry; J. Livingstone

2008-01-01

95

High sensitivity neutron detector for Z  

NASA Astrophysics Data System (ADS)

We have developed, calibrated, and tested a high sensitivity neutron detector that can be operated in the harsh x-ray bremsstrahlung environment that exists in experiments conducted on the 20 MA Z z-pinch facility located at Sandia National Laboratories in Albuquerque, New Mexico. The detector uses a scintillator coupled to a microchannel-plate photomultiplier tube detector and extensive x-ray shielding.

Ruggles, L. E.; Porter, J. L.; Simpson, W. W.; Vargas, M. F.; Zagar, D. M.; Hartke, R.; Buersgens, F.; Symes, D. R.; Ditmire, T.

2004-10-01

96

Developments of highly sensitive DNA sensors  

NASA Astrophysics Data System (ADS)

The large enhancements of optical properties of the dye-intercalated DNA lead us to apply the dye-intercalated DNA as various sensors with a high sensitivity to detect environmentally toxic gases such as dioxine, NOx or carbon monoxide. This paper retorts on DNA sensors for the further applications of DNA as materials. Also, bio-medical applications of DNA sensors such as a glucose sensor are reported.

Ogata, Naoya

2011-09-01

97

Highly sensitive catalytic spectrophotometric determination of ruthenium  

NASA Astrophysics Data System (ADS)

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 (? 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.

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

2008-01-01

98

Quantitative determination of mithramycin in human plasma by a novel, sensitive ultra-HPLC-MS/MS method for clinical pharmacokinetic application.  

PubMed

Mithramycin is a neoplastic antibiotic synthesized by various Streptomyces bacteria. It is under investigation as a chemotherapeutic treatment for a wide variety of cancers. Ongoing and forthcoming clinical trials will require pharmacokinetic analysis of mithramycin in humans, both to see if target concentrations are achieved and to optimize dosing and correlate outcomes (response/toxicity) with pharmacokinetics. Two published methods for mithramycin quantitation exist, but both are immunoassays that lack current bioanalytical standards of selectivity and sensitivity. To provide an upgraded and more widely applicable assay, a UPLC-MS/MS method for quantitation of mithramycin in human plasma was developed. Solid-phase extraction allowed for excellent recoveries (>90%) necessary for high throughput analyses on sensitive instrumentation. However, a ?55% reduction in analyte signal was observed as a result of plasma matrix effects. Mithramycin and the internal standard chromomycin were separated on a Waters Acquity BEH C18 column (2.150mm, 1.7?m) and detected using electrospray ionization operated in the negative mode at mass transitions m/z 1083.5?268.9 and 1181.5?269.0, respectively, on an AB Sciex QTrap 5500. The assay range was 0.5-500ng/mL and proved to be linear (r(2)>0.996), accurate (?10% deviation), and precise (CV<15%). Mithramycin was stable in plasma at room temperature for 24h, as well as through three freeze-thaw cycles. This method was subsequently used to quantitate mithramycin plasma concentrations from patients enrolled on two clinical trials at the NCI. PMID:25247492

Roth, Jeffrey; Peer, Cody J; Widemann, Brigitte; Cole, Diane E; Ershler, Rachel; Helman, Lee; Schrump, David; Figg, William D

2014-11-01

99

Photodetector having high speed and sensitivity  

DOEpatents

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.

Morse, Jeffrey D. (Martinez, CA); Mariella, Jr., Raymond P. (Danville, CA)

1991-01-01

100

Highly sensitive catalytic determination of molybdenum.  

PubMed

A novel, highly sensitive, selective, and simple kinetic method was developed for the determination of Mo(VI) based on its catalytic effect on the oxidation of 1-amino-2-naphthol-4-sulfonic acid (ANSA) with H(2)O(2). The reaction was followed spectrophotometrically by tracing the oxidized product at 465nm after 30min of mixing the reagents. The optimum reaction conditions were: 10mmol l(-1) ANSA, 50mmol l(-1) H(2)O(2), 100mmol l(-1) acetate buffer of pH 5.0+/-0.05 and at 40 degrees C. Addition of 200microg ml(-1) diethylenetriaminepentaacetic acid (DTPA) conferred high selectivity for the proposed method. Following the recommended procedure, Mo(VI) could be determined with a linear calibration graph up to 2.5ng ml(-1) and a detection limit, based on the 3S(b)-criterion, of 0.027ng ml(-1). The unique sensitivity and selectivity of the implemented method allowed its direct application to the determination of Mo(VI) in natural and industrial waste water. The method was validated by comparison with the standard ETAAS method. Moreover, published catalytic-spectrophotometric methods for the determination of molybdenum were reviewed. PMID:19071352

Mubarak, Ahmed T; Mohamed, Ashraf A; Fawy, Khaled F; Al-Shihry, Ayed S

2007-02-15

101

High-sensitivity detection of TNT  

PubMed Central

We report high-sensitivity detection of 2,4,6-trinitrotoluene (TNT) by using laser photoacoustic spectroscopy where the laser radiation is obtained from a continuous-wave room temperature high-power quantum cascade laser in an external grating cavity geometry. The external grating cavity quantum cascade laser is continuously tunable over ?400 nm around 7.3 ?m and produces a maximum continuous-wave power of ?200 mW. The IR spectroscopic signature of TNT is sufficiently different from that of nitroglycerine so that unambiguous detection of TNT without false positives from traces of nitroglycerine is possible. We also report the results of spectroscopy of acetylene in the 7.3-?m region to demonstrate continuous tunability of the IR source. PMID:17164325

Pushkarsky, Michael B.; Dunayevskiy, Ilya G.; Prasanna, Manu; Tsekoun, Alexei G.; Go, Rowel; Patel, C. Kumar N.

2006-01-01

102

High speed curved position sensitive detector  

DOEpatents

A high speed curved position sensitive porportional counter detector for use in x-ray diffraction, the detection of 5-20 keV photons and the like. The detector employs a planar anode assembly of a plurality of parallel metallic wires. This anode assembly is supported between two cathode planes, with at least one of these cathode planes having a serpentine resistive path in the form of a meander having legs generally perpendicular to the anode wires. This meander is produced by special microelectronic fabrication techniques whereby the meander "wire" fans outwardly at the cathode ends to produce the curved aspect of the detector, and the legs of the meander are small in cross-section and very closely spaced whereby a spatial resolution of about 50 .mu.m can be achieved. All of the other performance characteristics are about as good or better than conventional position sensitive proportional counter type detectors. Count rates of up to 40,000 counts per second with 0.5 .mu.s shaping time constants are achieved.

Hendricks, Robert W. (Montgomery County, VA); Wilson, Jack W. (Knox County, TN)

1989-01-01

103

Highly sensitive microwave temperature-jump apparatus.  

PubMed

A temperature-jump apparatus with repetitive microwave heating and spectrophotometric detection is described. Temperature jumps of 1.5 degrees C are achieved in a flow microcell within 1.5 mus (two shorter heating times of 0.5 and 0.25 mus are also available) at a repetition rate up to 50 Hz. On-line accumulation of the relaxation signals is performed with a PDP 11 processor, leading to very short recording times (more than 1000 signals accumulated in less than 50 s) and to a sensitivity better than 10(-4) optical density (OD) units. Nonlinear identification treatment permits processing the summed signal even when it is strongly blurred by noise. To demonstrate the capabilities of our apparatus, highly shifted fast prototropic equilibria in aqueous solutions of pyrimidine base have been studied. PMID:18699338

Aubard, J; Nozeran, J M; Levoir, P; Meyer, J J; Dubois, J E

1979-01-01

104

Highly sensitive silicon microreactor for catalyst testing  

SciTech Connect

A novel microfabricated chemical reactor for highly sensitive measurements of catalytic activity and surface kinetics is presented. The reactor is fabricated in a silicon chip and is intended for gas-phase reactions at pressures ranging from 0.1 to 5.0 bar. A high sensitivity is obtained by directing the entire gas flow through the catalyst bed to a mass spectrometer, thus ensuring that nearly all reaction products are present in the analyzed gas flow. Although the device can be employed for testing a wide range of catalysts, the primary aim of the design is to allow characterization of model catalysts which can only be obtained in small quantities. Such measurements are of significant fundamental interest but are challenging because of the low surface areas involved. The relationship between the reaction zone gas flow and the pressure in the reaction zone is investigated experimentally. A corresponding theoretical model is presented, and the gas flow through an on-chip flow-limiting capillary is predicted to be in the intermediate regime. The experimental data for the gas flow are found to be in good agreement with the theoretical model. At typical experimental conditions, the total gas flow through the reaction zone is around 3x10{sup 14} molecules s{sup -1}, corresponding to a gas residence time in the reaction zone of about 11 s. To demonstrate the operation of the microreactor, CO oxidation on low-area platinum thin film circles is employed as a test reaction. Using temperature ramping, it is found that platinum catalysts with areas as small as 15 {mu}m{sup 2} are conveniently characterized with the device.

Henriksen, Toke R.; Hansen, Ole [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark); Department of Physics, Danish National Research Foundation's Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, Building 312, DK-2800 Kgs. Lyngby (Denmark); Olsen, Jakob L.; Vesborg, Peter; Chorkendorff, Ib [Department of Physics, Danish National Research Foundation's Center for Individual Nanoparticle Functionality (CINF), Technical University of Denmark, Building 312, DK-2800 Kgs. Lyngby (Denmark)

2009-12-15

105

Highly sensitive electrochemical methyltransferase activity assay.  

PubMed

A simple and highly sensitive electrochemical DNA methyltransferase (MTase) activity assay is presented in this report. The assay employs the electrocatalytic oxidation of ascorbic acid (AA) by a threading intercalator (N,N'-bis(3-propylimidazole)-1,4,5,8-naphthalene diimide (PIND) functionalized with electrocatalytic redox Os(bpy)2Cl(+) moieties (PIND-Os)). Briefly, a double-stranded DNA (ds-DNA) containing the symmetric sequence of 5'-CCGG-3' is first immobilized on a gold electrode. The electrode is then incubated with M.SssI CpG methyltransferase (M.SssI MTase) which catalyzes the methylation of the specific CpG dinucleotides, and the electrode is subsequently treated with a restriction endonuclease HpaII which recognizes the 5'-CCGG-3' sequence. Once the CpG site in the 5'-CCGG-3' is methylated, HpaII recognition is blocked. Higher M.SssI MTase activity leads to more CpG sites being methylated and consequently impedes more the restriction endonuclease HpaII digestion process. Thus, a larger amount of ds-DNA remains on the electrode surface after the HpaII treatment. Thereafter, the electrode is incubated with PIND-Os during which PIND-Os specifically inserts itself between base pairs of ds-DNA and catalyzes the electrooxidation of AA. The methylation event corresponding to the MTase activity can therefore be monitored and amplified by the electrocatalytic oxidation of AA. A linear correlation between the catalytic oxidation current of AA and the activity of M.SssI MTase ranged from 0 to 120 U/mL with a current sensitivity of 0.046 ?A mL U(-1) is obtained. The inhibitor screening ability of the developed MTase activity assay is also demonstrated. PMID:24471506

Deng, Huimin; Yang, Xinjian; Yeo, Stephanie Pei Xing; Gao, Zhiqiang

2014-02-18

106

Demonstration of high sensitivity laser ranging system  

NASA Technical Reports Server (NTRS)

We report on a high sensitivity semiconductor laser ranging system developed for the Gravity and Magnetic Earth Surveyor (GAMES) for measuring variations in the planet's gravity field. The GAMES laser ranging instrument (LRI) consists of a pair of co-orbiting satellites, one which contains the laser transmitter and receiver and one with a passive retro-reflector mounted in an drag-stabilized housing. The LRI will range up to 200 km in space to the retro-reflector satellite. As the spacecraft pair pass over the spatial variations in the gravity field, they experience along-track accelerations which change their relative velocity. These time displaced velocity changes are sensed by the LRI with a resolution of 20-50 microns/sec. In addition, the pair may at any given time be drifting together or apart at a rate of up to 1 m/sec, introducing a Doppler shift into the ranging signals. An AlGaAs laser transmitter intensity modulated at 2 GHz and 10 MHz is used as fine and medium ranging channels. Range is measured by comparing phase difference between the transmit and received signals at each frequency. A separate laser modulated with a digital code, not reported in this paper, will be used for coarse ranging to unambiguously determine the distance up to 200 km.

Millar, Pamela S.; Christian, Kent D.; Field, Christopher T.

1994-01-01

107

High sensitivity optical position sensitive detectors fabricated from high resistivity substrates  

NASA Astrophysics Data System (ADS)

Position sensitive detectors (PSDs) comprise optical sensors used in applications such as robotic vision, machine tool alignment and other precision measurements. This paper will report on a series of Schottky Barrier crystalline silicon devices which display marked advantages including rapid response times, easier fabrication techniques and high sensitivities compared with most other research work now being concentrated on PECVD amorphous silicon structures. In this work, results from devices fabricated from substrates with a range of resistivities and various Schottky metals are presented. Some of the sensitivity measurements obtained are better than 25 mV/mm which are some of the best sensitivities reported for Schottky barrier crystalline PSDs. These results were obtained coincidentally with excellent linearities. Devices were also tested under a range of light beams including very low broadband white light levels of 0.1mW up to 10mW. The highest and most linear outputs occurred under different conditions for each substrate resistivity and Schottky metal. Also observed were the different effects that background illumination had on each set of devices, the biggest effect being on the highest resistivity devices.

Henry, J.; Livingstone, J.

2008-04-01

108

High Temperature Fatigue; Dwell Sensitivity and Life Prediction.  

National Technical Information Service (NTIS)

The objectives of this research were to develop knowledge to address dwell sensitivity behavior of high temperature materials and to predict dwell sensitivity and creep-fatigue life. The damage mechanisms resulting from various dwell cycles were summarize...

T. Goswami

1999-01-01

109

A case of high noise sensitivity  

NASA Astrophysics Data System (ADS)

A case of noise sensitivity with a five-year follow-up period is reported. The patient was a 34-year-old single man who was diagnosed as having psychosomatic disorder triggered by two stressful life events in rapid succession with secondary hypersensitivity to noise. Hypersensitivity to light and cold also developed later in the clinical course. The auditory threshold was within the normal range. The discomfort threshold as a measure of the noise sensitivity secondary to mental illness was measured repeatedly using test tone of audiometry. The discomfort threshold varied depending upon his mental status, ranging from 40-50 dB in the comparatively poorer mental state to 70-95 dB in the relatively good mental state. The features of noise sensitivity, including that secondary to mental illness, are discussed.

Murata, M.; Sakamoto, H.

1995-10-01

110

High-frequency sensitivity in infants.  

PubMed

Auditory thresholds were determined for infants and adults to half-octave bands of noise centered at 10,000 and 19,000 hertz. Adults were significantly more sensitive than infants at 10,000 hertz, but at 19,000 hertz, adults and infants had comparable thresholds. PMID:7352294

Schneider, B; Trehub, S E; Bull, D

1980-02-29

111

Transplantation in the highly sensitized pediatric patient.  

PubMed

Sensitization against HLA antigens is a growing problem in the field of pediatric cardiac transplantation. Although surgical outcomes for congenital heart disease have improved over the decades, these successes have added to the growing list of sensitized patients who eventually may require transplantation.Cardiac transplantation survival has improved, but morbidity and mortality secondary to HLA antibodies hinder outcome. Aside from acute hemodynamic compromise, there is compelling evidence linking sensitization and AMR with the development of CAV, a major limiting factor affecting long-term graft survival. Clinical advances have improved our understanding of the roles of antibody type, CFAs and non-CFAs, and DSAs and non-DSAs. Therapeutic strategies target both the T- and B-cell lines. Combinations that include plasmapheresis, IVIG, cyclophosphamide, and rituximab have been used in clinical studies with variable success.Two newer agents show promise, targeting both ends of the antibody-mediated spectrum: Bortezomib depletes plasma cell populations, and eculizumab blocks the terminal effects of antibody action, thus preventing myocardial cell dysfunction and death. Despite numerous diagnostic and therapeutic advances, many questions remain about the best approaches.The role of HLA antibodies remains the central target of investigation. PMID:24891624

Castleberry, Chesney; Ryan, Thomas D; Chin, Clifford

2014-06-01

112

High sensitivity leak detection method and apparatus  

DOEpatents

An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1 [times] 10[sup [minus]18] atm cc sec[sup [minus]1]. 2 figs.

Myneni, G.R.

1994-09-06

113

High sensitivity leak detection method and apparatus  

DOEpatents

An improved leak detection method is provided that utilizes the cyclic adsorption and desorption of accumulated helium on a non-porous metallic surface. The method provides reliable leak detection at superfluid helium temperatures. The zero drift that is associated with residual gas analyzers in common leak detectors is virtually eliminated by utilizing a time integration technique. The sensitivity of the apparatus of this disclosure is capable of detecting leaks as small as 1.times.10.sup.-18 atm cc sec.sup.-1.

Myneni, Ganapatic R. (Grafton, VA)

1994-01-01

114

Highly sensitive magnetite nano clusters for MR cell imaging  

NASA Astrophysics Data System (ADS)

High sensitivity and suitable sizes are essential for magnetic iron oxide contrast agents for cell imaging. In this study, we have fabricated highly MR sensitive magnetite nanoclusters (MNCs) with tunable sizes. These clusters demonstrate high MR sensitivity. Especially, water suspensions of the MNCs with average size of 63 nm have transverse relaxivity as high as 630 s-1mM-1, which is among the most sensitive iron oxide contrast agents ever reported. Importantly, such MNCs have no adverse effects on cells (RAW 264.7). When used for cell imaging, they demonstrate much higher efficiency and sensitivity than those of SHU555A (Resovist), a commercially available contrast agent, both in vitro and in vivo, with detection limits of 3,000 and 10,000 labeled cells, respectively. The studied MNCs are sensitive for cell imaging and promising for MR cell tracking in clinics.

Li, Mingli; Gu, Hongchen; Zhang, Chunfu

2012-03-01

115

High-Sensitivity GaN Microchemical Sensors  

NASA Technical Reports Server (NTRS)

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.

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

2009-01-01

116

Triggers for a high sensitivity charm experiment  

SciTech Connect

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.

Christian, D.C.

1994-07-01

117

Notch sensitivity of high strenght steels  

Microsoft Academic Search

A steel with 0.64-0.66~ 0.78-0.85 Mn, 0.24-0.28 Si and 0.22-0.23 Mo, as well as other high-strength steels were tested. The test results on Soviet steels displayed in Fig. 3 agree with the data in [1,2]. The fatigue limit was determined on rotating 7.5 mm dia specimens with a 0.75 mm notch radius. Fig. 4 shows that the fatigue limit of

M. P. Markovets

1960-01-01

118

Simultaneous quantification of seven plasma metabolites of sulfur mustard by ultra high performance liquid chromatography-tandem mass spectrometry.  

PubMed

Sulfur mustard (SM) is a hazardous chemical warfare agent that has been used in several military conflicts. SM is also considered as a major threat to civilians because of its existing stockpiles and easy production. Analysis of exposure biomarkers in biological samples collected from suspected victims is a useful tool for early diagnosis of SM poisoning. In this study, a sensitive and rapid quantitative method with ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for simultaneous determination of seven SM plasma biomarkers, including its oxidative, hydrolysis and ?-lyase metabolites. A simple one-step protein precipitation with acetonitrile-methanol (4:1) was used for sample preparation. A full validation was conducted with respect to specificity, linearity, recovery, matrix effect, precision, accuracy and stability. The lower limits of quantification for the seven metabolites ranged from 0.01?gL(-1) to 5?gL(-1). The intraday relative standard deviation was less than 7.0%, and the interday deviation was less than 9.1%. The recoveries varied in the range from 82.8% to 118%. This method has been successfully applied to a toxicokinetic study for obtaining the plasma profiles of seven metabolites in SM-exposed rats, following a single subcutaneous dose of 3.3mgkg(-1). All the targeted compounds were detected in rat plasma. bis-?-Chloroethyl sulfoxide (SMO), thiodiglycol (TDG), thiodiglycol sulfoxide (TDGO), 1,1'-sulfonylbis-[2-S-(N-acetylcysteinyl)ethane (SBSNAE), 1,1'-sulfonylbis-[2-(methylsulfinyl)ethane] (SBMSE) and 1-methylsulfinyl-2-[2-(methylthio)ethylsulfonyl]ethane (MSMTESE) were found to be the major metabolites in rat plasma. The time windows for the detection of these metabolites were varied in the range of 5min to 48h after exposure. The method provides a useful tool for short-term diagnosis of SM poisoning. PMID:23369883

Li, Chunzheng; Chen, Jia; Liu, Qin; Xie, Jianwei; Li, Hua

2013-02-15

119

Fabrication of sensitive high Tc bolometers  

NASA Technical Reports Server (NTRS)

The rapid change of resistance with temperature of high quality films of high T sub c superconductors can be used to make resistance thermometers with very low temperature noise. Measurements on c-axis yttrium barium copper oxide (YBCO) films have given a spectral intensity of temperature noise less than 4 times 10(exp -8) K/Hz(exp 1/2) at 10 Hz. Consequently, the opportunity exists to make useful bolometric infrared detectors that operate near 90 K which can be cooled with liquid nitrogen. The fabrication and measurement of two bolometer architectures are discussed. The first is a conventional bolometer which consists of a 3000 A thick YBCO film deposited in situ by laser ablation on top of a 500 A thick SrTiO3 thickness and diced into 1x1 mm(exp 2) bolometer chips. Gold black smoke was used as the radiation absorber. The voltage noise was less than the amplifier noise when the film was current biased. Optical measurements gave an NEP of 5 times 10(exp -11) W/Hz(exp 1/2) at 10 Hz. The second architecture is that of an antenna-coupled microbolometer which consists of a small (5x10 cubic microns) YBCO film deposited directly on a bulk substrate with a low thermal conductance (YSZ) and an impedance matched planar lithographed spiral or log-periodic antenna. This structure is produced by standard photolithographic techniques. Measurements gave an electrical NEP of 4.7 times 10(exp -12) W/Hz(exp 1/2) at 10 kHz. Measurements of the optical efficiency are in progress. The measured performance of both bolometers will be compared to other detectors operating at or above liquid nitrogen temperatures so as to identify potential applications.

Nahum, Michael; Verghese, S.; Hu, Qing; Richards, Paul L.; Char, K.; Newman, N.; Sachtjen, Scott A.

1990-01-01

120

[Analysis of 8-oxo-7,8-dihydro-2'-deoxyguanosine using ultra high performance liquid chromatography-tandem mass spectrometry].  

PubMed

An ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the analysis of biomarker 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-OHdG) in deoxyribonucleic acid (DNA) was developed. The artificial oxidation of 2'-deoxyguanosine (dG) at numerous stages in the sample preparation bring a challenge to the accurate measurement of 8-OHdG in DNA. To avoid the artificial oxidation during the enzymatic digestion, desferrioxamine mesylate as a protectant was added into the mixtures. By utilizing YM-3 Centricon membrane (3 000 of relative molecular mass cut off), excess proteins in enzymatic solutions were effectively removed, allowing direct UPLC-MS/MS analysis. The UPLCMS/MS analysis showed a linear relationship between the peak areas and the amounts of 8-OHdG in the range of 17.6-1400 fmol, and the correlation coefficient was 0.9998. By using the developed method, the content of 8-OHdG in calf thymus DNA (CT DNA) was estimated about 12.9 +/- 2.35 (calculated as 8-OHdG/10(6) dG), which was consistent with the previous work. This method can also be applicable for the detection of 8-OHdG in DNA under various oxidative stresses. PMID:21438362

Song, Yuling; Wang, Hailin

2010-12-01

121

Polymer microfiber rings for high-sensitivity optical humidity sensing.  

PubMed

We demonstrate microrings assembled with polyacrylamide (PAM) microfibers for high-sensitivity relative humidity (RH) sensing. When exposed to moisture, the PAM microfiber absorbs water molecules and inflates monotonically with the increasing humidity, resulting in evident spectral shifts of the resonance peaks of the microring. By measuring the spectral shifts, the microring shows sensitivity as high as 490 pm/%RH and a response time of about 120 ms, within a dynamic range from 5% to 71% RH. PMID:22086051

Wang, Pan; Gu, Fuxing; Zhang, Lei; Tong, Limin

2011-11-01

122

Fabrication of High Sensitivity Carbon Microcoil Pressure Sensors  

PubMed Central

This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS). CMCs were grown by chemical vapor deposition using various ratios of Fe-Sn catalytic solution. The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers. The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system. The yields of the growth of CMCs at a catalyst proportion of Fe:Sn = 95:5 reach 95%. Experimental results show that the sensor achieves a high sensitivity of 0.93%/kPa from the CMC yield of 95%. The sensitivity of the pressure sensor increases with increasing yield of CMCs. The demonstrated pressure sensor shows the advantage of high sensitivity and is suitable for mass production. PMID:23112586

Su, Chih-Chung; Li, Chen-Hung; Chang, Neng-Kai; Gao, Feng; Chang, Shuo-Hung

2012-01-01

123

Fabrication of high sensitivity carbon microcoil pressure sensors.  

PubMed

This work demonstrates a highly sensitive pressure sensor that was fabricated using carbon microcoils (CMCs) and polydimethylsiloxane (PDMS). CMCs were grown by chemical vapor deposition using various ratios of Fe-Sn catalytic solution. The pressure sensor has a sandwiched structure, in which the as-grown CMCs were inserted between two PDMS layers. The pressure sensor exhibits piezo-resistivity changes in response to mechanical loading using a load cell system. The yields of the growth of CMCs at a catalyst proportion of Fe:Sn = 95:5 reach 95%. Experimental results show that the sensor achieves a high sensitivity of 0.93%/kPa from the CMC yield of 95%. The sensitivity of the pressure sensor increases with increasing yield of CMCs. The demonstrated pressure sensor shows the advantage of high sensitivity and is suitable for mass production. PMID:23112586

Su, Chih-Chung; Li, Chen-Hung; Chang, Neng-Kai; Gao, Feng; Chang, Shuo-Hung

2012-01-01

124

Development of highly sensitive monolithic interferometer for infrared planet search  

Microsoft Academic Search

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 mum. 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

J. Wang; J. Ge; X. Wan; P. Jiang; B. Lee

2011-01-01

125

Highly sensitive optical microresonator sensors for photoacoustic imaging  

NASA Astrophysics Data System (ADS)

We present novel concave Fabry Perot (FP) sensor arrays for photoacoustic imaging which were fabricated using a high-precision inkjet printing approach to produce the cavity and employed physical vapor deposition to form the dielectric mirrors. Our concave FP cavity design provides excellent beam confinement within the cavity enabling high finesse and thus high sensitivity to be achieved. Two such concave sensors are evaluated in terms of their sensitivity and acoustic bandwidth. A 66 ?m thick concave sensor is shown to provide a noise equivalent pressure (NEP) of 85 Pa and an acoustic bandwidth of 16 MHz, and can potentially be used as a sensitive broadband sensor for superficial imaging. A 250 ?m thick sensor with an NEP of 12 Pa and acoustic bandwidth of 4 MHz was also developed for deep tissue imaging applications.

Li, Jing; Taylor, Alaric; Papakonstantinou, Ioannis; Zhang, Edward; Beard, Paul

2014-03-01

126

Analytical Glycobiology at High Sensitivity: Current Approaches and Directions  

PubMed Central

This review summarizes the analytical advances made during the last several years in the structural and quantitative determinations of glycoproteins in complex biological mixtures. The main analytical techniques used in the fields of glycomics and glycoproteomics involve different modes of mass spectrometry and their combinations with capillary separation methods such as microcolumn liquid chromatography and capillary electrophoresis. The needs for high-sensitivity measurements have been emphasized in the oligosaccharide profiling used in the field of biomarker discovery through MALDI mass spectrometry. High-sensitivity profiling of both glycans and glycopeptides from biological fluids and tissue extracts has been aided significantly through lectin preconcentration and the uses of affinity chromatography. PMID:22945852

Novotny, Milos V.; Alley, William R.; Mann, Benjamin F.

2013-01-01

127

Highly sensitive surface plasmon terahertz imaging with planar plasmonic crystals.  

PubMed

We report on the operation of a highly sensitive terahertz imaging system relying on a planar metallic plasmonic crystal as a terahertz surface plasmon resonant (THz-SPR) sensor. The terahertz imaging is based on the resonantly enhanced transmission phenomenon of a periodically perforated metal film. The detection sensitivity and the imaging contrast for small amounts of substance are considerably better than those of the conventional terahertz transmission imaging without a THz-SPR sensor. As a demonstration, a high contrast image of a fingerprint recorded on a thin film can be achieved by using this system. PMID:19550760

Miyamaru, F; Takeda, M W; Suzuki, T; Otani, C

2007-10-29

128

Highly sensitive bovine serum albumin biosensor based on liquid crystal  

NASA Astrophysics Data System (ADS)

A highly sensitive liquid crystal (LC) based bovine serum albumin (BSA) protein biosensor is designed. A uniform homeotropic alignment of nematic LC was observed in BSA free substrate which changed into homogeneous in presence of BSA. The change in the LC orientation is found to depend strongly on BSA concentration. This change in the LC alignment is attributed to the modification in the surface conditions which is verified by contact angle measurements. We have detected an ultra low concentration (0.5 ?g/ml) of BSA. The present study demonstrates the utilization of LC in the realization of high sensitivity biosensors.

Sharma, Vikash; Kumar, Ajay; Ganguly, Prasun; Biradar, A. M.

2014-01-01

129

High-sensitivity determination of birefringence in turbid media with enhanced polarization-sensitive optical coherence tomography  

Microsoft Academic Search

Polarization-sensitive optical coherence tomography provides high-resolution cross-sectional characterization of birefringence in turbid media. Weakly birefringent biological tissues such as the retinal nerve fiber layer (RNFL) require advanced speckle noise reduction for high-sensitivity measurement of form birefringence. We present a novel method for high-sensitivity birefringence quantification by using enhanced polarization-sensitive optical coherence tomography (EPS-OCT) and introduce the polarimetric signal-to-noise ratio, a

Nate J. Kemp; Haitham N. Zaatari; H. Grady Rylander; Thomas E. Milner

2005-01-01

130

HIGHLY SENSITIVE BIOASSAYS FOR EVALUATING AIRBORNE MUTAGENS INDOORS  

EPA Science Inventory

The standard mutagenicity bioassays that are readily applied to the valuation of outdoor air samples collected by high volume samplers are not efficiently sensitive to measure the mutagenicity of low volume air samples collected indoors. wo microsuspension mutation assays using v...

131

A high sensitivity inductive sensor for blade tip clearance measurement  

NASA Astrophysics Data System (ADS)

A multiplexed inductive sensor consisting of multiple mini-sized planar spiral coils for detecting multiple tip clearances of rotor blades is presented. The sensor measures the tip clearances by monitoring the inductance changes of planar spiral coils caused by the passage of the rotor blades. A resonance frequency division multiplexing technique and parallel LC resonance measurement were applied to the multiple sensor coils, making it feasible to measure multiple tip clearances using only one set of measurement electronics with high sensitivity and resolution. The results from tests conducted on a bench-top test rig have demonstrated that the sensor is capable of simultaneously measuring multiple tip clearances from 0 to 5 mm with a 10 ?m resolution at a high rotary speed up to 80?000 RPM. With its high resolution, high sensitivity and capability of monitoring a large number of tip clearances simultaneously, this sensor can potentially be used for advanced active tip clearance control in turbine machinery.

Du, Li; Zhu, Xiaoliang; Zhe, Jiang

2014-06-01

132

Part III. (1) The Grit Sensitiveness of High Explosives  

Microsoft Academic Search

Risks in handling various high explosives are enhanced if grit is present. Quantitative measurements of the enhanced sensitiveness, made by means of the Rotter impact machine, have included tests on the high explosives: T.N.T., picric acid, tetryl, cyclonite and waxed cyclonite, and penta-erythritol tetranitrate (P.E.T.N.). In addition to the standard Rotter test on the explosives as used in practice, experimental

J. L. Copp; A. R. Ubbelohde

1948-01-01

133

A High Sensitivity Ultraviolet Spectrograph for the THEIA Mission  

Microsoft Academic Search

We present the layout and performance specifications for the high sensitivity ultraviolet spectrograph (UVS) designed for the THEIA mission. Designed to revolutionize absorption-line spectroscopy in the 100-300 nm wavelength range, UVS will perform medium resolution (R 30,000) and high-resolution (R 100,000) observations of objects ranging from distant quasars to planets around nearby stars. Among its many science objectives, UVS will

Kenneth Sembach; D. Ebbets; V. Argabright; M. Beasley; M. Blouke; J. Green; E. Jenkins; J. MacKenty; W. Oegerle; J. X. Prochaska; J. M. Shull; O. Siegmund; T. Tripp; B. Woodgate; P. Scowen; D. Spergel

2009-01-01

134

Electrooptic modulation methods for high sensitivity tunable diode laser spectroscopy  

NASA Technical Reports Server (NTRS)

A CdTe phase modulator and low power RF sources have been used with Pb-salt tunable diode lasers operating near 8 microns to generate optical sidebands for high sensitivity absorption spectroscopy. Sweep averaged, first-derivative sample spectra of CH4 were acquired by wideband phase sensitive detection of the electrooptically (EO) generated carrier-sideband beat signal. EO generated beat signals were also used to frequency lock the TDL to spectral lines. This eliminates low frequency diode jitter, and avoids the excess laser linewidth broadening that accompanies TDL current modulation frequency locking methods.

Glenar, David A.; Jennings, Donald E.; Nadler, Shacher

1990-01-01

135

High-sensitivity linear piezoresistive transduction for nanomechanical beam resonators.  

PubMed

Highly sensitive conversion of motion into readable electrical signals is a crucial and challenging issue for nanomechanical resonators. Efficient transduction is particularly difficult to realize in devices of low dimensionality, such as beam resonators based on carbon nanotubes or silicon nanowires, where mechanical vibrations combine very high frequencies with miniscule amplitudes. Here we describe an enhanced piezoresistive transduction mechanism based on the asymmetry of the beam shape at rest. We show that this mechanism enables highly sensitive linear detection of the vibration of low-resistivity silicon beams without the need of exceptionally large piezoresistive coefficients. The general application of this effect is demonstrated by detecting multiple-order modes of silicon nanowire resonators made by either top-down or bottom-up fabrication methods. These results reveal a promising approach for practical applications of the simplest mechanical resonators, facilitating its manufacturability by very large-scale integration technologies. PMID:25000256

Sansa, Marc; Fernndez-Reglez, Marta; Llobet, Jordi; San Paulo, lvaro; Prez-Murano, Francesc

2014-01-01

136

Fluorinated-Polymer Based High Sensitivity Extreme Ultraviolet Resists  

NASA Astrophysics Data System (ADS)

There is a growing interest in the fluorinization of resist materials in improving pattern formation efficiency for extreme ultraviolet (EUV) lithography. The increased polymer absorption coefficient obtained through this resist platform is expected to enhance acid production and in effect improve pattern formation efficiency. Based on this, a EUV resist which was synthesized by co-polymerizing tetrafluoroethelyne (TFE) and functional norbornene derivative was investigated. Relatively high sensitivity of 6.3 mJ\\cdotcm-2 for half-pitch (hp) 45 nm and satisfactory resolution limit of hp 40 nm was achieved. However, at present, line width roughness (LWR) was measured at comparatively large values of more than 8.4 nm at hp 45 nm. Further material and process optimizations may be necessary to improve its present lithographic capability. However, these initial results have shown the potential of fluorinated-polymer based platform as a possible solution for high sensitivity, high resolution and low LWR EUV resists.

Julius Joseph Santillan,; Tsuneo Yamashita,; Masamichi Morita,; Yoshito Tanaka,; Toshiro Itani,

2010-06-01

137

Fluorinated-Polymer Based High Sensitivity Extreme Ultraviolet Resists  

NASA Astrophysics Data System (ADS)

There is a growing interest in the fluorinization of resist materials in improving pattern formation efficiency for extreme ultraviolet (EUV) lithography. The increased polymer absorption coefficient obtained through this resist platform is expected to enhance acid production and in effect improve pattern formation efficiency. Based on this, a EUV resist which was synthesized by co-polymerizing tetrafluoroethelyne (TFE) and functional norbornene derivative was investigated. Relatively high sensitivity of 6.3 mJcm-2 for half-pitch (hp) 45 nm and satisfactory resolution limit of hp 40 nm was achieved. However, at present, line width roughness (LWR) was measured at comparatively large values of more than 8.4 nm at hp 45 nm. Further material and process optimizations may be necessary to improve its present lithographic capability. However, these initial results have shown the potential of fluorinated-polymer based platform as a possible solution for high sensitivity, high resolution and low LWR EUV resists.

Santillan, Julius Joseph; Yamashita, Tsuneo; Morita, Masamichi; Tanaka, Yoshito; Itani, Toshiro

2010-06-01

138

A High Sensitivity Ultraviolet Spectrograph for the THEIA Mission  

NASA Astrophysics Data System (ADS)

We present the layout and performance specifications for the high sensitivity ultraviolet spectrograph (UVS) designed for the THEIA mission. Designed to revolutionize absorption-line spectroscopy in the 100-300 nm wavelength range, UVS will perform medium resolution (R 30,000) and high-resolution (R 100,000) observations of objects ranging from distant quasars to planets around nearby stars. Among its many science objectives, UVS will determine the baryonic content, ionization, and distribution of the intergalactic medium with sensitivities and cosmic volume grasp orders of magnitude larger than those of previous observatories. We are presently conducting an Astrophysics Strategic Mission Concept Study that is focusing on key technology development areas needed to enable UVS and other high performance spectrographs within the next decade. These include ultraviolet detector quantum efficiency and format, optimization of optical coatings, grating efficiency and aberration correction, and optical design. The UVS design and study results will serve as inputs into NASA's strategic planning process.

Sembach, Kenneth; Ebbets, D.; Argabright, V.; Beasley, M.; Blouke, M.; Green, J.; Jenkins, E.; MacKenty, J.; Oegerle, W.; Prochaska, J. X.; Shull, J. M.; Siegmund, O.; Tripp, T.; Woodgate, B.; Scowen, P.; Spergel, D.

2009-01-01

139

High-sensitivity EUV resists based on fluorinated polymers  

NASA Astrophysics Data System (ADS)

There is a growing interest in the fluorinization of resist materials in improving pattern formation efficiency for extreme ultraviolet (EUV) lithography. The increased polymer absorption coefficient obtained through this resist platform is expected to enhance acid production and in effect improve pattern formation efficiency. Our work over the past several years has shown that the main-chain fluorinated base resins realized by the co-polymerization of tetrafluoroethylene (TFE) and norbornene derivatives offer high dissolution rates. Based on this, a EUV resist which was prepared using the by the fluorinated polymers was investigated. Imaging evaluations, using the small field exposure tool (SFET by Canon / EUVA) with annular (?outer 0.7 / ?inner 0.3) illumination conditions were performed. Relatively high sensitivity of 6.3mJcm-2 for half-pitch (hp) 45nm and satisfactory resolution limit of hp 40nm was achieved. At present, line width roughness (LWR) was measured at comparatively large values of more than 8.4nm at hp 45nm. This shows that further material and process optimizations may be necessary to improve its present lithographic capability. However, these initial results have shown the potential of fluorinated-polymer based platform as a possible solution for high sensitivity, high resolution and low LWR EUV resists. In this paper, we report recent results of high sensitivity of 5.1mJcm-2 for half-pitch (hp) 40nm, optimization of protecting groups and photo acid generators

Yamashita, Tsuneo; Morita, Masamichi; Tanaka, Yoshito; Santillan, Julius Joseph; Itani, Toshiro

2011-04-01

140

High-sensitivity three-mode optomechanical transducer  

SciTech Connect

Three-mode optomechanical interactions have been predicted to allow the creation of very high sensitivity transducers in which very strong optical self-cooling and strong optomechanical quantum entanglement are predicted. Strong coupling is achieved by engineering a transducer in which both the pump laser and a single signal sideband frequency are resonantly enhanced. Here we demonstrate that very high sensitivity can be achieved in a very simple system consisting of a Fabry-Perot cavity with CO{sub 2} laser thermal tuning. We demonstrate a displacement sensitivity of {approx}1x10{sup -17} m/{radical}(Hz), which is sufficient to observe a thermally excited acoustic mode in a 5.6 kg sapphire mirror with a signal-to-noise ratio of more than 20 dB. It is shown that a measurement sensitivity of {approx}2x10{sup -20} m/{radical}(Hz) limited by the quantum shot noise is achievable with optimization of the cavity parameters.

Zhao, C.; Fang, Q.; Susmithan, S.; Miao, H.; Ju, L.; Fan, Y.; Blair, D.; Hosken, D. J.; Munch, J.; Veitch, P. J.; Slagmolen, B. J. J. [School of Physics, University of Western Australia, 35 Stirling Highway, Nedlands, Western Australia, 6009 (Australia); Department of Physics, University of Adelaide, Adelaide, South Australia, 5005 (Australia); Centre for Gravitational Physics, Australian National University, Canberra, 0200 (Australia)

2011-12-15

141

Very low frequency/high sensitivity triaxial monolithic inertial sensor  

NASA Astrophysics Data System (ADS)

This paper describes a new mechanical implementation of a triaxial sensor, configurable as seismometer and/or as accelerometer, consisting of three one-dimensional monolithic FP sensors, suitably geometrically positioned. The triaxial sensor is, therefore, compact, light, scalable, tunable instrument (frequency < 100mHz), with large band (10-7 Hz - 10Hz), high quality factor (Q > 2500 in air) with good immunity to environmental noises, guaranteed by an integrated laser optical readout. The measured sensitivity curve is in very good agreement with the theoretical ones (10-12m/?Hz) in the band (0.1 10Hz). Typical applications are in the field of earthquake engineering, geophysics, civil engineering and in all applications requiring large band-low frequency performances coupled with high sensitivities.

Acernese, F.; De Rosa, R.; Giordano, G.; Romano, R.; Barone, F.

2014-03-01

142

Quantum-Dot-Sensitized Solar Cell with Unprecedentedly High Photocurrent  

PubMed Central

The reported photocurrent density (JSC) of PbS quantum dot (QD)-sensitized solar cell was less than 19 mA/cm2 despite the capability to generate 38?mA/cm2, which results from inefficient electron injection and fast charge recombination. Here, we report on a PbS:Hg QD-sensitized solar cell with an unprecedentedly high JSC of 30?mA/cm2. By Hg2+ doping into PbS, JSC is almost doubled with improved stability. Femtosecond transient study confirms that the improved JSC is due to enhanced electron injection and suppressed charge recombination. EXAFS reveals that Pb-S bond is reinforced and structural disorder is reduced by interstitially incorporated Hg2+, which is responsible for the enhanced electron injection, suppressed recombination and stability. Thanks to the extremely high JSC, power conversion efficiency of 5.6% is demonstrated at one sun illumination. PMID:23308343

Lee, Jin-Wook; Son, Dae-Yong; Ahn, Tae Kyu; Shin, Hee-Won; Kim, In Young; Hwang, Seong-Ju; Ko, Min Jae; Sul, Soohwan; Han, Hyouksoo; Park, Nam-Gyu

2013-01-01

143

High-sensitivity, single-beam n2 measurements  

Microsoft Academic Search

We present a simple yet highly sensitive single-beam experimental technique for the determination of both the sign and magnitude of n2. The sample is moved along the z direction of a focused Gaussian beam while the repetitively pulsed laser energy is held fixed. The resultant plot of transmittance through an aperture in the far field yields a dispersion-shaped curve from

Mahsoor Sheik-Bahae; A. A. Said; Eric W. van Stryland

1989-01-01

144

An embedded high sensitivity navigation receiver for GPS  

Microsoft Academic Search

A high sensitivity navigation receiver based on FPGA and DSP was presented in this paper, which performed to mitigate cross correlations between multiple satellite signals. The hardware was consisted of RF parts, FPGA and DSP. The core chips were SPARTAN3 and TMS320VC5402, which were adapted to process navigation data and calculate user position. The RF Front-End received the navigation signal

Yangchun Shi; Lingwen Zhang; YouBao Liu

2011-01-01

145

Novel type of cryogenic liquid level sensor with high sensitivity  

NASA Astrophysics Data System (ADS)

The results of experiments carried out during the investigation of the thermoelectric force of different high Tc superconductors led to the development of a cryogenic liquid level indicator. These sensors can be easily realized using high temperature superconductors based on different high Tc compounds, such as compounds of the Y-Ba-Cu-O 123, iron doped 123, 124, and 5611 and Bi-(Pb)-Ca-Sr-Cu-O systems in both bulk ceramic and thick film form. The measuring equipment designed in the study is suitable for examination of different high Tc materials to be used as cryogenic liquid level indicators. An example demonstrates the method of selection of the proper high Tc material, the sensitivity of the material, and the simplicity of the application.

Immonen, E.; Uusimaki, A.; Hagberg, J.; Leppavuori, S.; Porjesz, T.

146

A simple, tunable, and highly sensitive radio-frequency sensor  

PubMed Central

We report a radio frequency (RF) sensor that exploits tunable attenuators and phase shifters to achieve high-sensitivity and broad band frequency tunability. Three frequency bands are combined to enable sensor operations from ?20?MHz to ?38?GHz. The effective quality factor (Qeff) of the sensor is as high as ?3.8??106 with 200??l of water samples. We also demonstrate the measurement of 2-proponal-water-solution permittivity at 0.01 mole concentration level from ?1?GHz to ?10?GHz. Methanol-water solution and de-ionized water are used to calibrate the RF sensor for the quantitative measurements. PMID:24023393

Cui, Yan; Sun, Jiwei; He, Yuxi; Wang, Zheng; Wang, Pingshan

2013-01-01

147

New approach to 3-D, high sensitivity, high mass resolution space plasma composition measurements  

Microsoft Academic Search

This paper describes a new type of 3-D space plasma composition analyzer. The design combines high sensitivity, high mass resolution measurements with somewhat lower mass resolution but even higher sensitivity measurements in a single compact and robust design. While the lower resolution plasma measurements are achieved using conventional straight-through time-of-flight mass spectrometry, the high mass resolution measurements are made by

David J. McComas; Jane E. Nordholt

1990-01-01

148

Sensitivity to Error Fields in NSTX High Beta Plasmas  

SciTech Connect

It was found that error field threshold decreases for high ? in NSTX, although the density correlation in conventional threshold scaling implies the threshold would increase since higher ? plasmas in our study have higher plasma density. This greater sensitivity to error field in higher ? plasmas is due to error field amplification by plasmas. When the effect of amplification is included with ideal plasma response calculations, the conventional density correlation can be restored and threshold scaling becomes more consistent with low ? plasmas. However, it was also found that the threshold can be significantly changed depending on plasma rotation. When plasma rotation was reduced by non-resonant magnetic braking, the further increase of sensitivity to error field was observed.

Jong-Kyu Park, Jonathan E. Menard, Stefan P. Gerhardt, Richard J. Buttery, Steve A. Sabbagh, Ronald E. Bell and Benoit P. LeBlanc

2011-11-07

149

High sensitivity tests of the standard model for electroweak interactions  

SciTech Connect

The work done on this project was focussed mainly on LAMPF experiment E969 known as the MEGA experiment, a high sensitivity search for the lepton family number violating decay {mu} {yields} e{gamma} to a sensitivity which, measured in terms of the branching ratio, BR = ({mu}{yields}e{gamma})/({mu}{yields}e {nu}{sub {mu}} {nu}{sub e}) {approx}10{sup {minus}13} is over two orders of magnitude better than previously reported values. The work done on MEGA during this period was divided between that done at Valparaiso University and that done at LAMPF. In addition, some contributions were made to a proposal to the LAMPF PAC to perform a precision measurement of the Michel {rho} parameter, described below.

Koetke, D.D.

1992-01-01

150

A CMOS In-Pixel CTIA High Sensitivity Fluorescence Imager  

PubMed Central

Traditionally, charge coupled device (CCD) based image sensors have held sway over the field of biomedical imaging. Complementary metal oxide semiconductor (CMOS) based imagers so far lack sensitivity leading to poor low-light imaging. Certain applications including our work on animal-mountable systems for imaging in awake and unrestrained rodents require the high sensitivity and image quality of CCDs and the low power consumption, flexibility and compactness of CMOS imagers. We present a 132124 high sensitivity imager array with a 20.1 ?m pixel pitch fabricated in a standard 0.5 ? CMOS process. The chip incorporates n-well/p-sub photodiodes, capacitive transimpedance amplifier (CTIA) based in-pixel amplification, pixel scanners and delta differencing circuits. The 5-transistor all-nMOS pixel interfaces with peripheral pMOS transistors for column-parallel CTIA. At 70 fps, the array has a minimum detectable signal of 4 nW/cm2 at a wavelength of 450 nm while consuming 718 ?A from a 3.3 V supply. Peak signal to noise ratio (SNR) was 44 dB at an incident intensity of 1 ?W/cm2. Implementing 44 binning allowed the frame rate to be increased to 675 fps. Alternately, sensitivity could be increased to detect about 0.8 nW/cm2 while maintaining 70 fps. The chip was used to image single cell fluorescence at 28 fps with an average SNR of 32 dB. For comparison, a cooled CCD camera imaged the same cell at 20 fps with an average SNR of 33.2 dB under the same illumination while consuming over a watt. PMID:23136624

Murari, Kartikeya; Etienne-Cummings, Ralph; Thakor, Nitish; Cauwenberghs, Gert

2012-01-01

151

Long sample high sensitivity critical current measurements under strain  

NASA Astrophysics Data System (ADS)

The extreme strain sensitivity of the critical current in Nb 3Sn superconductors at high fields is well known and must be taken into account in the design of high field magnets where strains up to 0.5% may be encountered. Current density/field measurements are relatively easy to perform but current density/strain measurements require fairly elaborate equipment and are time consuming in their execution. As a result commercial data is readily available for predicting current density at a particular field for a particular conductor but its measurement at a particular strain is less available. In this Paper an apparatus is described in which the sample is attached on the outside of the turns of a very thick spiral spring such that when one end of the spring is rotated with respect to the other the outer surface and, therefore, the sample is either stretched or even compressed. The sample geometry of six turns of 40 mm diameter over a length of 70 mm, is very similar to that typically used in current density/field measurements and using it strain tests can similarly be easily performed. Long samples can be tested in small bore ( ? 55 mm) solenoids where > 1-2% field variation can be achieved over the measured length and current transfer effects can be avoided so that unambiguous measurements can be obtained at a sensitivity of > 1.0 ?Vm-1. The strain sensitivity of the conductors used in this work increased between 3.6 and 5.4% per decade increase in electric field sensitivity at 11 T.

Walters, C. R.; Davidson, I. M.; Tuck, G. E.

152

Development of Highly Sensitive Temperature Sensor Using Ni foil  

NASA Astrophysics Data System (ADS)

This paper describes the development of a highly sensitive Ni foil temperature sensor. The element structure of the Ni foil temperature sensor is constructed from Ni foil with approx.3 ?m in thickness bonded on to crystallized glass with epoxy resin and measures just 0.78.00.3 mm, yet its resistance value is 1 k?. A fine pattern is fabricated in the Ni foil using photo etching technology. The size of the sensing part of the stainless steel protective tube, which houses the Ni sensing element, is a mere, ?130 mm. Optimal conditions for the main manufacturing processes of the sensor were determined by examining the crystal structure and stress on the Ni foil using an X-ray diffractometer, X-ray stress analyzer and SEM. Ni temperature sensors fabricated using these optimal conditions exhibited high sensitivity and stable performance. TCR is 6600ppm/C between 0C and 100C, the same as pure Ni wire, and is stable at room temperature with a drift of 0.005C/year. After calibration this temperature sensor is highly accurate with a fast thermal response time. Therefore the Ni foil temperature sensor is applied to precision manufacturing, semiconductor and other industries where high accuracy is demanded.

Ichida, Shunji; Okamoto, Tohru; Yamaguchi, Toru; Kumehara, Hiroyuki

153

Position sensitive detection of neutrons in high radiation background field  

NASA Astrophysics Data System (ADS)

We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high ? and e- radiation background. We make use of a planar silicon pixelated (pixel size: 55 55 ?m2) spectroscopic Timepix detector adapted for neutron detection utilizing very thin 10B converter placed onto detector surface. We demonstrate that electromagnetic radiation background can be discriminated from the neutron signal utilizing the fact that each particle type produces characteristic ionization tracks in the pixelated detector. Particular tracks can be distinguished by their 2D shape (in the detector plane) and spectroscopic response using single event analysis. A Cd sheet served as thermal neutron stopper as well as intensive source of gamma rays and energetic electrons. Highly efficient discrimination was successful even at very low neutron to electromagnetic background ratio about 10-4.

Vavrik, D.; Jakubek, J.; Pospisil, S.; Vacik, J.

2014-01-01

154

Ultrathin plasmonic nanogratings for rapid and highly-sensitive detection  

E-print Network

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...

Zeng, Beibei; Bartoli, Filbert J

2014-01-01

155

Highly sensitive electrochemiluminescent nanobiosensor for the detection of palytoxin.  

PubMed

Marine toxins appear to be increasing in many areas of the world. An emerging problem in the Mediterranean Sea is represented by palytoxin (PlTX), one of the most potent marine toxins, frequently detected in seafood. Due to the high potential for human toxicity of PlTX, there is a strong and urgent need for sensitive methods toward its detection and quantification. We have developed an ultrasensitive electrochemiluminescence-based sensor for the detection of PlTX, taking advantage of the specificity provided by anti-PlTX antibodies, the good conductive properties of carbon nanotubes, and the excellent sensitivity achieved by a luminescence-based transducer. The sensor was able to produce a concentration-dependent light signal, allowing PlTX quantification in mussels, with a limit of quantification (LOQ = 2.2 ?g/kg of mussel meat) more than 2 orders of magnitude more sensitive than that of the commonly used detection techniques, such as LC-MS/MS. PMID:22913785

Zamolo, Valeria Anna; Valenti, Giovanni; Venturelli, Enrica; Chaloin, Olivier; Marcaccio, Massimo; Boscolo, Sabrina; Castagnola, Valentina; Sosa, Silvio; Berti, Federico; Fontanive, Giampaolo; Poli, Mark; Tubaro, Aurelia; Bianco, Alberto; Paolucci, Francesco; Prato, Maurizio

2012-09-25

156

High sensitivity chemically amplified EUV resists through enhanced EUV absorption  

NASA Astrophysics Data System (ADS)

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

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

2012-03-01

157

Interface engineering of a highly sensitive solution processed organic photodiode.  

PubMed

We report on tuning of the interfacial properties of a highly sensitive organic photodiode by introducing a buffer layer between the anode and the semiconductor layer. The effects of different buffer layers consisting of a self-assembled monolayer (SAM), PEDOT:PSS, and pentacene on the morphology and crystallinity of the upper-deposited bulk heterojunction semiconductor layer are carefully analyzed combined with electrical analysis. The active layer is controlled to be nearly homogeneous and to have low crystallinity by using a SAM or PEDOT:PSS buffer layers, whereas a highly crystalline morphology is realized by using the pentacene buffer layer. When exposed to light pulses, the external quantum efficiency and thus the photocurrent are slightly higher for the PEDOT:PSS-based photodiode; however the dark current is the lowest for the pentacene-based photodiode. We discuss the origin of the high sensitivity (a detectivity of 1.3 10(12) Jones and a linear dynamic range of 95 dB) of the pentacene-based photodiode, particularly in terms of the morphology-driven low dark current. PMID:25069515

Kim, Yu Jin; Park, Chan Eon; Chung, Dae Sung

2014-09-14

158

High Sensitivity Wavefront Sensing with a Nonlinear Curvature Wavefront Sensor  

NASA Astrophysics Data System (ADS)

A new wavefront sensing approach, derived from the successful curvature wavefront sensing concept but using a nonlinear phase retrieval wavefront reconstruction scheme, is described. The nonlinear curvature wavefront sensor (nlCWFS) approaches the theoretical sensitivity limit imposed by fundamental physics by taking full advantage of wavefront spatial coherence in the pupil plane. Interference speckles formed by natural starlight encode wavefront aberrations with the sensitivity set by the telescope's diffraction limit ?/D rather than the seeing limit of more conventional linear wavefront sensors (WFSs). Closed-loop adaptive optics simulations show that with an nlCWFS, a 100 nm rms wavefront error can be reached on an 8 m telescope on an m=13 natural guide star. The nlCWFS technique is best suited for high precision adaptive optics on bright natural guide stars. It is therefore an attractive technique to consider for direct imaging of exoplanets and disks around nearby stars, where achieved performance is set by wavefront control accuracy and exquisite control of low-order aberrations is essential for high contrast coronagraphic imaging. Performance gains derived from simulations are shown, and approaches for high speed reconstruction algorithms are briefly discussed.

Guyon, Olivier

2010-01-01

159

The Georgia Tech High Sensitivity Microwave Measurement System  

NASA Technical Reports Server (NTRS)

As observations and models of the planets become increasingly more accurate and sophisticated, the need for highly accurate laboratory measurements of the microwave properties of the component gases present in their atmospheres become ever more critical. This paper describes the system that has been developed at Georgia Tech to make these measurements at wavelengths ranging from 13.3 cm to 1.38 cm with a sensitivity of 0.05 dB/km at the longest wavelength and 0.6 db/km at the shortest wavelength.

Deboer, David R.; Steffes, Paul G.

1996-01-01

160

High sensitivity charge amplifier for ion beam uniformity monitor  

DOEpatents

An ion beam uniformity monitor for very low beam currents using a high-sensitivity charge amplifier with bias compensation. The ion beam monitor is used to assess the uniformity of a raster-scanned ion beam, such as used in an ion implanter, and utilizes four Faraday cups placed in the geometric corners of the target area. Current from each cup is integrated with respect to time, thus measuring accumulated dose, or charge, in Coulombs. By comparing the dose at each corner, a qualitative assessment of ion beam uniformity is made possible. With knowledge of the relative area of the Faraday cups, the ion flux and areal dose can also be obtained.

Johnson, Gary W. (Livermore, CA)

2001-01-01

161

High temperature fiber sensor based on spherical-shape structures with high sensitivity  

NASA Astrophysics Data System (ADS)

An optical fiber high temperature sensor is proposed and fabricated by cascading two spherical-shape structures, which are built by a section of single mode fiber (SMF). The spherical-shape structures can realize the coupling and recoupling between the core mode and the cladding modes. Experimental results show that the sensor is capable of monitoring temperature change from 25 C to 735 C with sensitivity of 0.1193 nm/C and the sensitivity of microstrain is -0.0012 nm/?? which is beneficial for encapsulation. The characteristics of the proposed sensor indicate compact, high sensitive and inexpensive properties, which can be widely applied in many fields.

Yuan, Shuo; Tong, Zhengrong; Zhao, Junfa; Zhang, Weihua; Cao, Ye

2014-12-01

162

A UPLC-MS Method for the Determination of Ofloxacin Concentrations in Aqueous Humor  

PubMed Central

A rapid, simple, and specific method based on ultra performance liquid chromatography (UPLC) with mass spectrometry detection has been developed for quantitative analysis of ofloxacin in human aqueous humor using tobramycin as internal standard (IS). Chromatographic separation was achieved on a Waters Acquity UPLC BEH C18 Shield column (150 2.1 mm, 1.7 ?m) eluted with 95:5 water: acetonitrile (v/v) containing 0.1% formic acid and a flow rate of 0.3 mL/minute. The total analysis time was three minutes with ofloxacin eluting at 1.67 0.03 minutes. The linearity of the method ranged from 0.1 to 8 ?g/mL with r2 = 0.998. The method was validated according to FDA guidelines with respect to linearity, accuracy, precision, specificity, and stability. The limits of detection and quantification were 0.03 and 0.10 ?g/mL, respectively. The developed method was successfully applied to the analysis of samples that have been obtained from patients. PMID:24868142

Plotas, Panagiotis; Anastasopoulos, Charalampos; Makri, Olga E; Leotsinidis, Michalis; Georgakopoulos, Constantine D

2014-01-01

163

[The impurity profiling of simvastatin and its tablets by UPLC-MS/MS].  

PubMed

Investigation of simvastatin and its related substances was carried out using a reversed phase ultra performance liquid chromatography/tandem mass spectrometry method. The identification of impurities in simvastatin was performed with a triple-quadrupole mass spectrometer, with an electrospray ionization (ESI) source in the negative/positive ion mode. A total of 12 compounds were characterized in commercial samples, among which 2 impurities had never been reported. All the impurities were deduced based on the MS fragment pathways of simvastatin and the biosynthetic pathway of lovastatin. This work provides very useful information for quality control of simvastatin. PMID:25151740

Li, Jie; Huang, Hai-Wei; Zhang, Hong; Li, Tao; Shi, Ya-Qin

2014-05-01

164

High Sensitivity Micro-Elastometry: Applications in Blood Coagulopathy  

PubMed Central

Highly sensitive methods for the assessment of clot structure can aid in our understanding of coagulation disorders and their risk factors. Rapid and simple clot diagnostic systems are also needed for directing treatment in a broad spectrum of cardiovascular diseases. Here we demonstrate a method for micro-elastometry, named Resonant Acoustic Spectroscopy with Optical Vibrometry (RASOV), which measures the clot elastic modulus (CEM) from the intrinsic resonant frequency of a clot inside a microwell. We observed a high correlation between the CEM of human blood measured by RASOV and a commercial Thromboelastograph (TEG), (R=0.966). Unlike TEG, RASOV requires only 150 ?L of sample and offers improved repeatability. Since CEM is known to primarily depend upon fibrin content and network structure, we investigated the CEM of purified clots formed with varying amounts of fibrinogen and thrombin. We found that RASOV was sensitive to changes of fibrinogen content (0.56 mg/mL), as well as to the amount of fibrinogen converted to fibrin during clot formation. We then simulated plasma hypercoagulability via hyperfibrinogenemia by spiking whole blood to 150% and 200% of normal fibrinogen levels, and subsequently found that RASOV could detect hyperfibrinogenemia-induced changes in CEM and distinguish these conditions from normal blood. PMID:23649979

Wu, Gongting; Krebs, Charles R.; Lin, Feng-Chang; Wolberg, Alisa S.; Oldenburg, Amy L.

2013-01-01

165

Highly Sensitive Detection of Urinary Cadmium to Assess Personal Exposure  

PubMed Central

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 ?A/ppb/cm2) 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 National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.251 ppb cadmium. PMID:23561905

Argun, Avni A.; Banks, Ashley; Merlen, Gwendolynne; Tempelman, Linda A.; Becker, Michael F.; Schuelke, Thomas; Dweik, Badawi

2013-01-01

166

Sensitivity study of reliable, high-throughput resolution metricsfor photoresists  

SciTech Connect

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.

Anderson, Christopher N.; Naulleau, Patrick P.

2007-07-30

167

Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.  

SciTech Connect

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 %22Click%22 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.

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

2013-09-01

168

High sensitivity permeation measurement system for 'ultrabarrier' thin films  

SciTech Connect

The authors demonstrate a new technique for high sensitivity gas permeation measurements by integrating mass spectrometry with programed accumulation, detection, and evacuation of permeant. After passing through the film of interest, the gas permeant is captured and accumulated in an isolated ultrahigh vacuum (UHV) volume. The permeant is then allowed to enter an adjacent residual gas analyzer (RGA) and the resulting partial pressure increase is correlated with the steady state permeation rate. Calibrated results are given for helium and argon permeation through polymer films. The measured detection limits of the system are 1.8x10{sup -4} cm{sup 3}/m{sup 2} day for helium and 2.5x10{sup -4} cm{sup 3}/m{sup 2} day for argon. Both values are several orders of magnitude lower than what is available from commercial instruments or similar RGA-based instruments. Potential applications of this technique include measurement of oxygen and water vapor permeation with sensitivities required for assessment of ultrabarrier coatings.

Zhang Xiaodong; Lewis, Jay S.; Wolter, Scott D.; Parker, Charles B.; Glass, Jeffrey T. [Pratt School of Engineering, Duke University, Durham, North Carolina 27708 (United States); RTI International, Research Triangle Park, North Carolina 27709 (United States); Pratt School of Engineering, Duke University, Durham, North Carolina 27708 (United States)

2007-11-15

169

Highly sensitive flow-injection chemiluminescence determination of pyrogallol compounds  

NASA Astrophysics Data System (ADS)

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.

Kanwal, Shamsa; Fu, Xiaohong; Su, Xingguang

2009-12-01

170

High sensitivity of tubifex for ultraviolet-B.  

PubMed

Phytoplankton and zooplankton serve as major food material for primary and secondary consumers in the marine food web. Although phytoplankton are primary targets to UV radiation damaging effects, we have demonstrated that stratospheric ozone depletion will affect zooplankton to contribute to inhibition in biomass production. In this study, an annilid Tubifex was irradiated under UVA, UVB, UVC or direct sunlight to demonstrate behavioral changes (motility and mortality). The organism showed varying degrees of sensitivity towards UVB and UVC. Even a small increment in UVB resulted in high degree of mortality. Interestingly, water turbidity seems to have a protective effect against UV exposure. These results strongly suggest that a change in UVB flux has direct impact on biomass production. PMID:9070900

Soni, A K; Joshi, P C

1997-02-24

171

Versatile, high-sensitivity faraday cup array for ion implanters  

DOEpatents

An improved Faraday cup array for determining the dose of ions delivered to a substrate during ion implantation and for monitoring the uniformity of the dose delivered to the substrate. The improved Faraday cup array incorporates a variable size ion beam aperture by changing only an insertable plate that defines the aperture without changing the position of the Faraday cups which are positioned for the operation of the largest ion beam aperture. The design enables the dose sensitivity range, typically 10.sup.11 -10.sup.18 ions/cm.sup.2 to be extended to below 10.sup.6 ions/cm.sup.2. The insertable plate/aperture arrangement is structurally simple and enables scaling to aperture areas between <1 cm.sup.2 and >750 cm.sup.2, and enables ultra-high vacuum (UHV) applications by incorporation of UHV-compatible materials.

Musket, Ronald G. (Danville, CA); Patterson, Robert G. (Dublin, CA)

2003-01-01

172

Highly sensitive hot electron bolometer based on disordered graphene  

PubMed Central

A bolometer is a device that makes an electrical resistive response to the electromagnetic radiation resulted from a raise of temperature due to heating. The combination of the extremely weak electron-phonon interactions along with its small electron heat capacity makes graphene an ideal material for applications in ultra-fast and sensitive hot electron bolometer. However, a major issue is that the resistance of pristine graphene weakly depends on the electronic temperature. We propose using disordered graphene to obtain a strongly temperature dependent resistance. The measured electrical responsivity of the disordered graphene bolometer reaches 6 106?V/W at 1.5?K, corresponding to an optical responsivity of 1.6 105?V/W. The deduced electrical noise equivalent power is 1.2 , corresponding to the optical noise equivalent power of 44?. The minimal device structure and no requirement for high mobility graphene make a step forward towards the applications of graphene hot electron bolometers. PMID:24346418

Han, Qi; Gao, Teng; Zhang, Rui; Chen, Yi; Chen, Jianhui; Liu, Gerui; Zhang, Yanfeng; Liu, Zhongfan; Wu, Xiaosong; Yu, Dapeng

2013-01-01

173

Radiation noise in a high sensitivity star sensor  

NASA Technical Reports Server (NTRS)

An extremely accurate attitude determination was developed for space applications. This system uses a high sensitivity star sensor in which the photomultiplier tube is subject to noise generated by space radiations. The space radiation induced noise arises from trapped electrons, solar protons and other ionizing radiations, as well as from dim star background. The solar activity and hence the electron and proton environments are predicted through the end of the twentieth century. The available data for the response of the phototube to proton, electron, gamma ray, and bremsstrahlung radiations are reviewed and new experimental data is presented. A simulation was developed which represents the characteristics of the effect of radiations on the star sensor, including the non-stationarity of the backgrounds.

Parkinson, J. B.; Gordon, E.

1972-01-01

174

Comparing standard Bonner spheres and high-sensitivity Bonner cylinders.  

PubMed

Standard Bonner spheres and proposed high-sensitivity Bonner cylinders were calibrated in a neutron calibration room, using a (252)Cf source. The Bonner sphere system consists of 11 polyethylene (PE) spheres of various diameters and 4 extended spheres that comprise embedded metal shells. Similar to the design of Bonner spheres, a set of Bonner cylinders was assembled using a large cylindrical (3)He tube as the central probe, which was wrapped using various thicknesses of PE. A layer of lead was employed inside one of the PE cylinders to increase the detection efficiency of high-energy neutrons. The central neutron probe used in the Bonner cylinders exhibited an efficiency of ?17.9 times higher than that of the Bonner spheres. However, compared with the Bonner spheres, the Bonner cylinders are not fully symmetric in their geometry, exhibiting angular dependence in their responses to incoming neutrons. Using a series of calculations and measurements, this study presents a systematic comparison between Bonner spheres and cylinders in terms of their response functions, detection efficiencies, angular dependences and spectrum unfolding. PMID:24366247

Lee, Kuo-Wei; Yuan, Ming-Chen; Jiang, Shiang-Huei; Sheu, Rong-Jiun

2014-10-01

175

New Ultra-High Sensitivity, Absolute, Linear, and Rotary Encoders  

NASA Technical Reports Server (NTRS)

Several new types of absolute optical encoders of both rotary and linear function are discussed. The means for encoding are complete departures from conventional optical encoders and offer advantages of compact form, immunity to damage-induced dropouts of position information, and about an order of magnitude higher sensitivity over what is commercially available. Rotary versions have sensitivity from 0.02 arcseconds down to 0.003 arcsecond while linear models have sensitivity of 10 nm.

Leviton, Douglas B.

1998-01-01

176

Highly sensitive and multiplexed platforms for allergy diagnostics  

NASA Astrophysics Data System (ADS)

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 offers four significant advantages compared to existing sensing technologies: IRIS i) corrects for any variation in probe immobilization, ii) detects proteins from attomolar to nanomolar concentrations in unprocessed biological samples, iii) unambiguously discriminates nanoparticles tags on a robust and physically large sensor area, iv) detects protein targets with conjugated nanoparticle tags (~40nm diameter), which minimally affect assay kinetics compared to conventional microparticle tagging methods, and v) utilizes components that make the instrument inexpensive, robust, and portable. This platform was successfully validated on patient serum and whole blood samples with documented allergy profiles (ImmunoCAPRTM, ThermoFisher Scientific).

Monroe, Margo R.

177

Sensitivity Analysis of Cell Neutronic Parameters in High-Conversion Light-Water Reactors  

Microsoft Academic Search

The sensitivity coefficients of neutronic performance parameters in high-conversion LWR cells have been calculated by means of the SAINT code. In order to show the specific features of the sensitivity coefficients in the HCLWR cells, the differences between sensitivities were investigated for cells with different moderator to fuel volume ratios and different Pu enrichments. The burnup dependence of the sensitivities

Makoto NAKANO; Toshikazu TAKEDA; Hideki TAKANO

1987-01-01

178

Capillary photoionization: a high sensitivity ionization method for mass spectrometry.  

PubMed

We present a capillary photoionization (CPI) method for mass spectrometric (MS) analysis of liquid and gaseous samples. CPI utilizes a heated transfer capillary with a vacuum ultraviolet transparent MgF2 window, through which vacuum UV light (10 eV) from an external source enters the capillary. The liquid or gaseous sample, together with dopant, is introduced directly into the heated transfer capillary between the atmosphere and the vacuum of the MS. Since the sample is vaporized and photoionized inside the capillary, ion transmission is maximized, resulting in good overall sensitivity for nonpolar and polar compounds. As in atmospheric pressure photoionization, ionization in CPI occurs either by proton transfer or by charge exchange reactions. The feasibility of CPI was demonstrated with selected nonpolar and polar compounds. A particular advantage of CPI is that it enables the analysis of nonvolatile and nonpolar compounds in liquid samples with high ionization efficiency. This is not possible with existing capillary ionization methods. The performance of CPI as an interface between GC and MS and its applicability for the analysis of steroids in biological samples are also demonstrated. The GC-CPI-MS method shows good chromatographic resolution, linearity (R(2) > 0.993), limits of detection (LOD) in the range of 2-6 pg/mL and repeatability of injection with relative standard deviations of 4-15%. PMID:23713722

Haapala, Markus; Suominen, Tina; Kostiainen, Risto

2013-06-18

179

Highly sensitive tube-topology magnetoelectric magnetic sensors  

NASA Astrophysics Data System (ADS)

Magnetoelectric (ME) composites have drawn increasing interest in recent years due to advancements in the technology resulting in enhanced ME coupling coefficients, stable room-temperature operation, sub-nanoTesla noise floor, low- and zero-biased operation, and fabrication of compact, miniaturized devices. Now, more than ever, practical use of ME devices in commercial magnetometry applications is feasible, while continued development of numerous other applications, such as voltage-tunable magnetic field generators, voltage-tunable inductors, and magnetically-tunable capacitors, bolster the overall usefulness of ME composites as a valuable technology. This dissertation focuses on development and characterization of tube-topology ME composites as magnetic field sensors. The novel topology is most notable for demonstrating high zero-external-bias sensitivity, low noise floor, low-frequency bandwidth, and self-powered, stable room temperature operation. Numerous characterization studies are included in this work where several devices are analyzed as a function of test-field, DC-bias field, geometry, material choice, and more. The overall conclusions drawn upon these results indicate strongly that the tube-topology ME magnetic field sensor holds promise to compete with existing hall-effect and flux-gate magnetometers. ME composites are at the tipping point of commercialization for use in magnetometry applications and are emerging as a valuable technology for use in numerous creative ways.

Gillette, Scott Matthew

180

Physical Activity and High-Sensitivity C-Reactive Protein  

PubMed Central

Background Previous studies have suggested an inverse relationship between physical activity and markers of inflammation such as high-sensitivity C-reactive protein (hs-CRP). However, these were inconsistent, and few examined whether race and gender influenced the relationship. This study determined a cross-sectional association between physical activity and hs-CRP level in 6142 middle-aged white, Chinese, black, and Hispanic participants enrolled in the Multi Ethnic Study of Atherosclerosis in 20002002. Methods Combined moderate and vigorous physical activity was measured by self-reported leisure, conditioning, occupational, and household activities. ANCOVA was used to assess the association between moderate/vigorous physical activity and hs-CRP by gender and race. Results Hs-CRP was higher in women. Blacks had the highest hs-CRP, and Chinese participants had the lowest. Hs-CRP decreased across tertiles of moderate/vigorous physical activity in Hispanic men in models adjusted for age, education, study site, and physical activity questionnaire mode of administration (p=0.005) and further adjusted for smoking, infection, and aspirin use (p=0.020). The trend remained significant after further adjustment for BMI; blood pressure; low-density lipoprotein cholesterol; high-density lipoprotein cholesterol; diabetes; and the use of antihypertensive, statin, and diabetes medication (p=0.044). There was a downward trend in hs-CRP across tertiles of physical activity in black and white men, but the association was weaker. No clear trend was observed in any female racial/ethnic groups. Conclusions These findings suggest that the association between moderate/vigorous physical activity and hs-CRP differs by race and gender. Further studies are needed to confirm this and to examine the mechanisms for these race and gender differences. PMID:19013748

Majka, Darcy S.; Chang, Rowland W.; Vu, Thanh-Huyen T.; Palmas, Walter; Geffken, Dominic F.; Ouyang, Pamela; Ni, Hanyu; Liu, Kiang

2013-01-01

181

Comparison of different calibration approaches for chloramphenicol quantification in chicken muscle by ultra-high pressure liquid chromatography tandem mass spectrometry.  

PubMed

Matrix-dependent signal suppression often occurs in quantitative analysis by ultra-high pressure liquid chromatography tandem mass spectrometry (UPLC-MS/MS). In this study, we investigated three calibration methods for compensation of signal suppression on chloramphenicol (CAP) quantification in chicken muscle. The data showed that the spiking recoveries by solvent standard calibration with a stable isotope labelled internal standard (SIL-IS) and matrix-matched standard calibration with a SIL-IS were significantly higher than by external matrix-matched standard calibration (P < 0.05). When the SIL-IS was used, standards prepared in the mobile phase solvent showed no significant difference as those prepared in the matrix (P > 0.05). The limit of detection (LOD) for external matrix matched standard calibration was 0.1 ?g kg(-1), and that for SIL-IS calibration (including matrix matched and solvent dissolved standard) was 0.03 ?g kg(-1). PMID:25406881

Pan, Xiao-Dong; Jiang, Wei; Wu, Ping-Gu

2014-12-01

182

The increased shock sensitivity of PBX 9502 at high temperature  

NASA Astrophysics Data System (ADS)

A modified gap test using brass attenuators has been designed that can significantly heat explosive samples prior to testing. The sensitivity of PBX 9502 when heated to 180, 200, 230 & 260C and soaked for 30 minutes was investigated. It was discovered that under the moderate confinement (0.46 MPa) of this test, the sensitivity of the material did increase close to literature data for LX-17 (a very similar composition) heated to 250C under numerically unquantified 'heavy confinement'.

Rae, P. J.; Baca, E. V.; Cartelli, A. R.; Holmes, M. D.; Kuiper, T. A.

2014-05-01

183

Sensitive, high-strain, high-rate bodily motion sensors based on graphene-rubber composites.  

PubMed

Monitoring of human bodily motion requires wearable sensors that can detect position, velocity and acceleration. They should be cheap, lightweight, mechanically compliant and display reasonable sensitivity at high strains and strain rates. No reported material has simultaneously demonstrated all the above requirements. Here we describe a simple method to infuse liquid-exfoliated graphene into natural rubber to create conducting composites. These materials are excellent strain sensors displaying 10(4)-fold increases in resistance and working at strains exceeding 800%. The sensitivity is reasonably high, with gauge factors of up to 35 observed. More importantly, these sensors can effectively track dynamic strain, working well at vibration frequencies of at least 160 Hz. At 60 Hz, we could monitor strains of at least 6% at strain rates exceeding 6000%/s. We have used these composites as bodily motion sensors, effectively monitoring joint and muscle motion as well and breathing and pulse. PMID:25100211

Boland, Conor S; Khan, Umar; Backes, Claudia; O'Neill, Arlene; McCauley, Joe; Duane, Shane; Shanker, Ravi; Liu, Yang; Jurewicz, Izabela; Dalton, Alan B; Coleman, Jonathan N

2014-09-23

184

High-sensitivity DPSK receiver for high-bandwidth free-space optical communication links.  

PubMed

A high-sensitivity modem and high-dynamic range optical automatic gain controller (OAGC) have been developed to provide maximum link margin and to overcome the dynamic nature of free-space optical links. A sensitivity of -48.9 dBm (10 photons per bit) at 10 Gbps was achieved employing a return-to-zero differential phase shift keying based modem and a commercial Reed-Solomon forward error correction system. Low-noise optical gain was provided by an OAGC with a noise figure of 4.1 dB (including system required input loses) and a dynamic range of greater than 60 dB. PMID:21643335

Juarez, Juan C; Young, David W; Sluz, Joseph E; Stotts, Larry B

2011-05-23

185

Sensitivity of fast-response nanographite photodetector at high temperature  

NASA Astrophysics Data System (ADS)

We studied performance of a fast-response nanographite film photodetector (PD) in the temperature range of 300- 1000 K. In experiment, we measured the magnitude of the electric signal generated in nanographite film (NGF) under irradiation of intense nanosecond laser pulses at ?=1.064 ?m. In vacuum, the measurements of the PD sensitivity were performed in the temperature range of 300-800 K. We showed experimentally that the PD sensitivity at 300 K was about 30% higher than that at 625 K and 50% higher than that at 740 K. At T>625 K, the magnitude of the light-induced signal decreases as a linear function of temperature and vanish at T ~ 1000 K. In atmospheric conditions, we observed a stable operation of the NGF-based PD during several tens of hours in the temperature range from 300 to 580 K. However, at higher temperature, degradation of the NG film resulted in a drop in the PD sensitivity.

Mikheev, Gennady M.; Zonov, Ruslan G.; Obraztsov, Alexander N.; Svirko, Yuri P.

2009-05-01

186

Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers.  

PubMed

The development of an electronic skin is critical to the realization of artificial intelligence that comes into direct contact with humans, and to biomedical applications such as prosthetic skin. To mimic the tactile sensing properties of natural skin, large arrays of pixel pressure sensors on a flexible and stretchable substrate are required. We demonstrate flexible, capacitive pressure sensors with unprecedented sensitivity and very short response times that can be inexpensively fabricated over large areas by microstructuring of thin films of the biocompatible elastomer polydimethylsiloxane. The pressure sensitivity of the microstructured films far surpassed that exhibited by unstructured elastomeric films of similar thickness, and is tunable by using different microstructures. The microstructured films were integrated into organic field-effect transistors as the dielectric layer, forming a new type of active sensor device with similarly excellent sensitivity and response times. PMID:20835231

Mannsfeld, Stefan C B; Tee, Benjamin C-K; Stoltenberg, Randall M; Chen, Christopher V H-H; Barman, Soumendra; Muir, Beinn V O; Sokolov, Anatoliy N; Reese, Colin; Bao, Zhenan

2010-10-01

187

High-sensitivity photoacoustic detection of chemical warfare agents  

NASA Astrophysics Data System (ADS)

We report sensitive and selective detection of Diisopropyl methylphosphonate (DIMP) - a decomposition product of Sarin and a common surrogate for the nerve gases - in presence of several gases expected to be interferences in an urban setting. By employing photoacosutic spectroscopy with broadly tunable CO2 laser as a radiation source we demonstrate detection sensitivity for DIMP in the presence of these interferences of better than 0.5 ppb in 60 second long measurement time, which satisfies most current homeland and military security requirements and validates the photoacoustic spectroscopy as a powerful technology for nerve gas sensing instrumentation.

Pushkarsky, Michael B.; Webber, Michael E.; MacDonald, Tyson; Patel, C. Kumar N.

2004-12-01

188

A high-sensitivity push-pull magnetometer  

E-print Network

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).

Breschi, E; Knowles, P; Weis, A

2013-01-01

189

High-sensitivity, high-selectivity detection of chemical warfare agents  

Microsoft Academic Search

We report high-sensitivity detection of chemical warfare agents (nerve gases) with very low probability of false positives (PFP). We demonstrate a detection threshold of 1.2 ppb (7.7 mug\\/m3 equivalent of Sarin) with a PFP of <1:106 in the presence of many interfering gases present in an urban environment through the detection of diisopropyl methylphosphonate, an accepted relatively harmless surrogate for

Michael B. Pushkarsky; Michael E. Webber; Tyson MacDonald; C. Kumar N. Patel

2006-01-01

190

High-sensitivity, high-selectivity detection of chemical warfare agents  

Microsoft Academic Search

We report high-sensitivity detection of chemical warfare agents (nerve gases) with very low probability of false positives (PFP). We demonstrate a detection threshold of 1.2 ppb (7.7 ?g?m3 equivalent of Sarin) with a PFP of <1:106 in the presence of many interfering gases present in an urban environment through the detection of diisopropyl methylphosphonate, an accepted relatively harmless surrogate for

Michael B. Pushkarsky; Michael E. Webber; Tyson Macdonald; C. Kumar N. Patel

2006-01-01

191

A High-Sensitivity Current Sensor Utilizing CrNi Wire and Microfiber Coils  

PubMed Central

We obtain an extremely high current sensitivity by wrapping a section of microfiber on a thin-diameter chromium-nickel wire. Our detected current sensitivity is as high as 220.65 nm/A2 for a structure length of only 35 ?m. Such sensitivity is two orders of magnitude higher than the counterparts reported in the literature. Analysis shows that a higher resistivity or/and a thinner diameter of the metal wire may produce higher sensitivity. The effects of varying the structure parameters on sensitivity are discussed. The presented structure has potential for low-current sensing or highly electrically-tunable filtering applications. PMID:24824372

Xie, Xiaodong; Li, Jie; Sun, Li-Peng; Shen, Xiang; Jin, Long; Guan, Bai-ou

2014-01-01

192

High sensitivity surface plasmon resonace sensor based on phase detection  

Microsoft Academic Search

A surface plasmon resonance sensing technique based on optical heterodyne phase detection is presented. The theoretical sensitivity of this new method is compared with traditioal surface plasmon resonance technique. The results of phase detection modeling shows a strong dependence on sensor film thickness. With a practical configuration, the resolution of refractive index is predicted to be 5 10?7 refractive

S. G Nelson; K. S Johnston; S. S Yee

1996-01-01

193

ORIGINAL PAPER Allergen microarrays on high-sensitivity silicon slides  

E-print Network

substrate for allergy diagnosis, in the detection of specific IgE in serum samples of subjects to discriminate between the allergy and no allergy status in 30 well-characterized serum samples. We found allergens. Keywords Protein microarrays . Diagnosis . Fluorescence . Allergy. Sensitivity. Specificity. ROC

194

Genetic influence on brain catecholamines: high brain norepinephrine in salt-sensitive rats  

SciTech Connect

Rats genetically sensitive to salt-induced hypertension evinced higher levels of plasma norepinephrine and epinephrine than rats genetically resistant to hypertension. The hypertension-sensitive rats showed higher hypothalamic norepinephrine and lower epinephrine than resistant rats. In response to a high salt diet, brain stem norepinephrine increased in sensitive rats while resistant rats exhibited a decrease on the same diet.

Iwai, J.; Friedman, R.; Tassinari, L.

1980-01-01

195

Extremely high frequency sensitivity in a 'simple' ear  

PubMed Central

An evolutionary war is being played out between the bat, which uses ultrasonic calls to locate insect prey, and the moth, which uses microscale ears to listen for the approaching bat. While the highest known frequency of bat echolocation calls is 212 kHz, the upper limit of moth hearing is considered much lower. Here, we show that the greater wax moth, Galleria mellonella, is capable of hearing ultrasonic frequencies approaching 300 kHz; the highest frequency sensitivity of any animal. With auditory frequency sensitivity that is unprecedented in the animal kingdom, the greater wax moth is ready and armed for any echolocation call adaptations made by the bat in the on-going batmoth evolutionary war. PMID:23658005

Moir, Hannah M.; Jackson, Joseph C.; Windmill, James F. C.

2013-01-01

196

High sensitive quartz crystal microbalance with porous gold electrodes  

NASA Astrophysics Data System (ADS)

Quartz crystal microbalance (QCM) is a useful device commonly employed as a thickness monitor in vacuum deposition, sputtering and chemical vapor deposition applications. The thickness of the adsorbed film is given by the decrease in the resonant frequency of the device. With care, the resonant frequency can be determined to 5 parts in 10^9. It is therefore also useful in sensor applications and as research device for nanotribology, wetting transition and superfluid transition studies. The sensitivity of the device is limited by the hydrodynamic, hydrostatic and temperature dependent correction on the resonant frequency. By replacing the conventional gold electrodes with porous gold electrodes, we have been able to enhance the mass sensitivity by a factor of 30 with no sacrifice of the mechanical quality factor. This study is supported by NSF MRSEC program under grant numbers DMR-0080019 and DMR-0213623.

Hieda, Mitsunori; Galcia, Rafael; Daniels, Tad; Dixson, Matt; Allara, David; Chan, Moses

2003-03-01

197

AERO-STRUCTURAL WING DESIGN OPTIMIZATION USING HIGH-FIDELITY SENSITIVITY ANALYSIS  

Microsoft Academic Search

This paper develops and implements a framework for the computation of cou- pled aero-structural sensitivities which are required for the design of aircraft where aeroelastic interactions are significant. All aero-structural sensitivities are computed using high-fidelity models of both the aerodynamics and the structure of the wing with a coupled-adjoint approach that uses single discipline sensitivity information to calculate the sensitivities

Joaquim R. R. A. Martins; Juan J. Alonso; James Reuther

2001-01-01

198

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

PubMed

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. PMID:25127159

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

2014-10-01

199

Super LOTIS a high sensitive optical counterpart search experiment  

SciTech Connect

We are constructing a 0.6 meter telescope system to search for early time gamma-ray burst (GRB) optical counterparts. Super-LOTIS (Super-Livermore Optical Transient Imaging System) is an automated telescope system that has a 0.8 x 0.8{degree} field-of-view, is sensitive to M{sub v} {approximately} 19 and responds to a burst trigger within 5 min. This telescope will record images of the gamma-ray burst coordinates that is given by the GCN (GRB Coordinate Network). A measurement of GRB light curves at early times will greatly enhance our understanding of GRB physics.

Park, H.S., Ables, E.; Band, D.L [and others

1997-11-17

200

Platinum decorated carbon nanotubes for highly sensitive amperometric glucose sensing  

NASA Astrophysics Data System (ADS)

Fine platinum nanoparticles (1-5 nm in diameter) were deposited on functionalized multi-walled carbon nanotubes (MWNTs) through a decoration technique. A novel type of enzymatic Pt/MWNTs paste-based mediated glucose sensor was fabricated. Electrochemical measurements revealed a significantly improved sensitivity (around 52.7 A mM-1 cm-2) for glucose sensing without using any picoampere booster or Faraday cage. In addition, the calibration curve exhibited a good linearity in the range of 1-28 mM of glucose concentration. Transmission electron microscopy (TEM) and x-ray photoelectron spectroscopy (XPS) were performed to investigate the nanoscale structure and the chemical bonding information of the Pt/MWNTs paste-based sensing material, respectively. The improved sensitivity of this novel glucose sensor could be ascribed to its higher electroactive surface area, enhanced electron transfer, efficient enzyme immobilization, unique interaction in nanoscale and a synergistic effect on the current signal from possible multi-redox reactions.

Xie, Jining; Wang, Shouyan; Aryasomayajula, L.; Varadan, V. K.

2007-02-01

201

High sensitivity 810 GHz SIS receivers at AST/RO  

NASA Astrophysics Data System (ADS)

In November 2003 the heterodyne receivers WANDA (polarization diplexed 492/810 GHz) and PoleSTAR (2x2 810 GHz array) of AST/RO (Antarctic Submillimeter Telescope and Remote Observatory, located at the South Pole) were upgraded with new 810 GHz SIS (Superconductor-Insulator-Superconductor) waveguide mixers from KOSMA. Profiting from device development for the HIFI (Heterodyne Instrument for the Far-Infrared) Band 2 SIS mixers of the Herschel Space Observatory, a factor of approx. 2 improvement in receiver noise temperature (from 1100 K to 550 K DSB) was achieved with WANDA. The SIS mixer devices employ low-loss NbTiN-Al tuning circuits and are fabricated using electron beam lithographic junction area definition and CMP (Chemical Mechanical Polishing) of the tuning circuit dielectric. With the South Pole being one of the best possible sites for ground-based submillimeter astronomy, the 1.7 m telescope currently makes AST/RO well suited for sensitive, large scale spectral line mapping at 810 GHz. Low atmospheric opacity (tau < 1) and, consequently, very low system noise temperatures (< 3000 K) are regularly achieved at 810 GHz, making AST/RO an extremely sensitive observatory at these frequencies. "First light" astronomical measurements made with the upgraded 810 GHz channel of WANDA towards the galactic HII region NGC 3576 in CO J=7-6 (806.65 GHz) and the neutral carbon [CI] 3P2-3P1 (809.3 GHz) lines are presented.

Ptz, Patrick; Glenz, Stefan; Teipen, Rafael; Tils, Thomas; Honingh, Netty; Jacobs, Karl; Hedden, Abigail; Kulesa, Craig; Groppi, Christopher E.; Walker, Christopher K.

2004-10-01

202

A new compact, high sensitivity neutron imaging system.  

PubMed

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(9)-10(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 10(10). The resolution of this image was 54 ?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 (60)Co ?-ray source. The calibration showed that the signal-to-noise ratio could be improved by using raw binning detection. PMID:23126952

Caillaud, T; Landoas, O; Briat, M; Ross, B; Thfoin, I; Philippe, F; Casner, A; Bourgade, J L; Disdier, L; Glebov, V Yu; Marshall, F J; Sangster, T C; Park, H S; Robey, H F; Amendt, P

2012-10-01

203

High sensitivity infrared 10.6 micrometer heterodyne receiver development  

NASA Technical Reports Server (NTRS)

The results are presented for a study on the design of an infrared 10.6-micrometer quantum-noise-limited optical receiver subsystem. Performance measurements of the HgCdTe photomixer preamplifier combination were carried out for photomixer temperatures up to 152 K and a photomixer frequency response of up to 420 MHz was obtained. Results of temperature and bias cycling of HgCdTe photomixers are reported. Design considerations for an operational 10.6 micrometer heterodyne receiver are presented. These consist of design data on required laser LO illumination, heat load levels for photomixer cooler, photomixer uniformity and the effects of photomixer impedance match on receiver sensitivity. Analysis and measurements of 10.6 micrometer heterodyne detection in an extrinsic photoconductive (p-type) HgCdTe photomixer are also presented.

1972-01-01

204

Development of High Sensitive Micro-Kerr Magnetometer H_^E` '  

E-print Network

Development of High Sensitive Micro-Kerr Magnetometer ·?H·_^ê·E­?`º ·' ·­ ·E`å'J-1 Hirosawa, Wako, Saitama 351-0198 We describe the detailed design of a highly sensitive magnetometer based·C micro-Kerr magnetometer 1·D,Í,¶,?,?

Otani, Yoshichika

205

Development of a high sensitivity Giant Magneto-Impedance magnetometer: comparison  

E-print Network

1 Development of a high sensitivity Giant Magneto-Impedance magnetometer: comparison of an operational giant magne- toimpedance (GMI)-based magnetometer, one of which is capable of working-Gate magnetometer, offering a low-cost solution for high sensitivity magnetometry. However, the proposed GMI

Paris-Sud XI, Université de

206

Development of Super-high Sensitivity Radon Detector for the Super-Kamiokande Detector  

E-print Network

collection, and upgraded electronics. Next, a super-high sensitivity full radon detector for water (700L element in the extraction of radon from water, with the electrostatic collection unit. 2 Super-high sensitivity radon detector for water which works as a real-time monitor of the radon concentration in water

Takeuchi, Yasuo

207

High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells  

E-print Network

High Excitation Transfer Efficiency from Energy Relay Dyes in Dye-Sensitized Solar Cells Brian E soluble energy relay dyes with high molar extinction coefficients. KEYWORDS Solar cell, energy transfer, dye-sensitized dolar cell, energy relay dye, titania L ong range energy transfer has recently been

McGehee, Michael

208

Highly sensitive glucose biosensor based on Au-Ni coaxial nanorod array having high aspect ratio.  

PubMed

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 ?m. 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 ?M-27.5mM with a detection limit of 5.5?M and a very high sensitivity of 769.6 ?A 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. PMID:24495482

Hsu, Che-Wei; Wang, Gou-Jen

2014-06-15

209

Highly sensitive homogenous chemiluminescence immunoassay using gold nanoparticles as label.  

PubMed

Homogeneous immunoassay is becoming more and more attractive for modern medical diagnosis because it is superior to heterogeneous immunoassay in sample and reagent consumption, analysis time, portability and disposability. Herein, a universal platform for homogeneous immunoassay, using human immunoglobulin G (IgG) as a model analyte, has been developed. This assay relies upon the catalytic activity of gold nanoparticles (AuNPs) on luminol-AgNO3 chemiluminescence (CL) reaction. The immunoreaction of antigen and antibody can induce the aggregation of antibody-functionalized AuNPs, and after aggregation the catalytic activity of AuNPs on luminol-AgNO3 CL reaction is greatly enhanced. Without any separation steps, a CL signal is generated upon addition of a trigger solution, and the CL intensity is directly correlated to the quantity of IgG. The detection limit of IgG was estimated to be as low as 3pg/mL, and the sensitivity was better than that of the reported AuNPs-based CL immunoassay for IgG. PMID:24835732

Luo, Jing; Cui, Xiang; Liu, Wei; Li, Baoxin

2014-10-15

210

HLA desensitization with bortezomib in a highly sensitized pediatric patient.  

PubMed

The proteasome inhibitor bortezomib has been used with variable success in the treatment of AMR following heart transplant. There is limited experience with this agent as a pretransplant desensitizing therapy. We report a case of successful HLA desensitization with a bortezomib-based protocol prior to successful heart transplantation. A nine-yr-old boy with dilated cardiomyopathy, not initially sensitized to HLA (cPRA of zero), required threedays of ECMO, followed by implantation of a Heartmate II LVAD. Within sixwk, the patient developed de novo class I IgG and C1q complement-fixing HLA antibodies with a cPRA of 100%. Two doses of IVIG (2g/kg) failed to reduce antibody levels, although two courses of a novel desensitization protocol consisting of rituximab (375mg/m(2) ), bortezomib (1.3mg/m(2) נ5 doses), and plasmapheresis reduced his cPRA to 0% and 87% by the C1q and IgG assays, respectively. He underwent heart transplantation nearly twomonths later. The patient is now >oneyr post-transplant, is free of both AMR and ACR, and has no detectable donor-specific antibodies by IgG or C1q. Proteasome inhibition with bortezomib and plasmapheresis may be an effective therapy for HLA desensitization pretransplant. PMID:25174602

May, Lindsay J; Yeh, Justin; Maeda, Katsuhide; Tyan, Dolly B; Chen, Sharon; Kaufman, Beth D; Bernstein, Daniel; Rosenthal, David N; Hollander, Seth A

2014-12-01

211

High sensitivity capacitive MEMS microphone with spring supported diaphragm  

NASA Astrophysics Data System (ADS)

Capacitive microphones (condenser microphones) work on a principle of variable capacitance and voltage by the movement of its electrically charged diaphragm and back plate in response to sound pressure. There has been considerable research carried out to increase the sensing performance of microphones while reducing their size to cater for various modern applications such as mobile communication and hearing aid devices. This paper reviews the development and current performance of several condenser MEMS microphone designs, and introduces a microphone with spring supported diaphragm to further improve condenser microphone performance. The numerical analysis using Coventor FEM software shows that this new microphone design has a higher mechanical sensitivity compared to the existing edge clamped flat diaphragm condenser MEMS microphone. The spring supported diaphragm is shown to have a flat frequency response up to 7 kHz and more stable under the variations of the diaphragm residual stress. The microphone is designed to be easily fabricated using the existing silicon fabrication technology and the stability against the residual stress increases its reproducibility.

Mohamad, Norizan; Iovenitti, Pio; Vinay, Thurai

2007-12-01

212

High-sensitivity observations of solar flare decimeter radiation  

E-print Network

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.

Arnold O. Benz; Peter Messmer; Christian Monstein

2000-12-05

213

Highly sensitive homogenous chemiluminescence immunoassay using gold nanoparticles as label  

NASA Astrophysics Data System (ADS)

Homogeneous immunoassay is becoming more and more attractive for modern medical diagnosis because it is superior to heterogeneous immunoassay in sample and reagent consumption, analysis time, portability and disposability. Herein, a universal platform for homogeneous immunoassay, using human immunoglobulin G (IgG) as a model analyte, has been developed. This assay relies upon the catalytic activity of gold nanoparticles (AuNPs) on luminol-AgNO3 chemiluminescence (CL) reaction. The immunoreaction of antigen and antibody can induce the aggregation of antibody-functionalized AuNPs, and after aggregation the catalytic activity of AuNPs on luminol-AgNO3 CL reaction is greatly enhanced. Without any separation steps, a CL signal is generated upon addition of a trigger solution, and the CL intensity is directly correlated to the quantity of IgG. The detection limit of IgG was estimated to be as low as 3 pg/mL, and the sensitivity was better than that of the reported AuNPs-based CL immunoassay for IgG.

Luo, Jing; Cui, Xiang; Liu, Wei; Li, Baoxin

2014-10-01

214

High Sensitivity of Giardia duodenalis to Tetrahydrolipstatin (Orlistat) In Vitro  

PubMed Central

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 (IC5024h?=?2.8 M) being more sensitive than WB-C6 (IC5024h?=?6.2 M). The effect was significantly more potent compared to MTZ (IC5024h?=?4.3 M and 11.0 M, respectively) and led to specific undulated morphological alterations on the parasite surface. The giardiacidal concentration of orlistat was >14 M for 14-03/F7 and >43 M 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. PMID:23977083

Hahn, Juliane; Seeber, Frank; Kolodziej, Herbert; Ignatius, Ralf; Laue, Michael; Aebischer, Toni; Klotz, Christian

2013-01-01

215

High-sensitivity dye binding assay for albumin in urine.  

PubMed

We developed a dye-binding method for albumin in urine based on bis (3',3"-diiodo4'4"-dihydroxy-5'5"-dinitrophenyl)-3,4,5,6-tetrabr omosulfonphthalein (DIDNTB), a dye that has a higher chemical sensitivity and specificity for albumin when compared to two other commonly used dyes. We prepared urine dipsticks with DIDNTB and certain other compounds to prevent "nonspecific" binding to the dipstick matrix. The detection limit for albumin with DIDNTB as the dye is about 10 mg/L. The extent of dye binding to proteins and other compounds was studied using ultracentrifugation and a selectively permeable membrane that permitted the passage of free but not bound dye; we believe this method is superior to photometric titration. The affinity of the dyes for albumin was found to be pH dependent with stronger binding at pH 1.8 than at pH 7.0. At pH 1.8, DIDNTB had a ca.10-fold greater binding coefficient to albumin when compared to the widely used dyes, tetrabromophenol blue (CI 4430-25-5) or bromophenol blue (CI 115-39-9). We developed a system that minimized nonspecific binding by the dye through the use of polymethyl vinyl ethers and bis-(heptapropylene glycol) carbonate. DIDNTB showed a greater chemical specificity for albumin when compared to most other proteins. The new albumin dipsticks are resistant to many potential interferences at substantial concentrations, making the dipsticks suitable to screen for albuminuria. PMID:10414598

Pugia, M J; Lott, J A; Profitt, J A; Cast, T K

1999-01-01

216

The highly sensitive brain: an fMRI study of sensory processing sensitivity and response to others' emotions  

PubMed Central

Background Theory and research suggest that sensory processing sensitivity (SPS), found in roughly 20% of humans and over 100 other species, is a trait associated with greater sensitivity and responsiveness to the environment and to social stimuli. Self-report studies have shown that high-SPS individuals are strongly affected by others' moods, but no previous study has examined neural systems engaged in response to others' emotions. Methods This study examined the neural correlates of SPS (measured by the standard short-form Highly Sensitive Person [HSP] scale) among 18 participants (10 females) while viewing photos of their romantic partners and of strangers displaying positive, negative, or neutral facial expressions. One year apart, 13 of the 18 participants were scanned twice. Results Across all conditions, HSP scores were associated with increased brain activation of regions involved in attention and action planning (in the cingulate and premotor area [PMA]). For happy and sad photo conditions, SPS was associated with activation of brain regions involved in awareness, integration of sensory information, empathy, and action planning (e.g., cingulate, insula, inferior frontal gyrus [IFG], middle temporal gyrus [MTG], and PMA). Conclusions As predicted, for partner images and for happy facial photos, HSP scores were associated with stronger activation of brain regions involved in awareness, empathy, and self-other processing. These results provide evidence that awareness and responsiveness are fundamental features of SPS, and show how the brain may mediate these traits. PMID:25161824

Acevedo, Bianca P; Aron, Elaine N; Aron, Arthur; Sangster, Matthew-Donald; Collins, Nancy; Brown, Lucy L

2014-01-01

217

UNCERTAINTY AND SENSITIVITY ANALYSES FOR VERY HIGH ORDER MODELS  

EPA Science Inventory

While there may in many cases be high potential for exposure of humans and ecosystems to chemicals released from a source, the degree to which this potential is realized is often uncertain. Conceptually, uncertainties are divided among parameters, model, and modeler during simula...

218

Effects of intrinsic magnetostriction on tube-topology magnetoelectric sensors with high magnetic field sensitivity  

NASA Astrophysics Data System (ADS)

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.

Gillette, Scott M.; Fitchorov, Trifon; Obi, Ogheneyunume; Jiang, Liping; Hao, Hongbo; Wu, Shuangxia; Chen, Yajie; Harris, Vincent G.

2014-05-01

219

First experiences with a high sensitive videocamera with internal multiframe exposure time  

NASA Astrophysics Data System (ADS)

This is a short report about the use of the high sensitive black-white video camera MTV-12V1-EX that allows to increase the sensitivity about 2 magnitudes in normal video mode and about 4 magnitudes by using the internal selectable multiframe exposure time with 0.3 sec time resolution (compared with sensitivity of simple black-white video cameras). A video record demonstrates some occultation events and starfields.

Rothe, Wolfgang

2002-07-01

220

Implicit and Explicit Memory for Threat Words in High and Low-Anxiety-Sensitive Participants  

Microsoft Academic Search

This study examined memory for anxiety andthreat words in high-anxiety-sensitive (HAS; n = 38) andlow-anxiety-sensitive (LAS; n = 36) participants. Basedon Foa and Kozak's (1986) information processing theory of fear, it was hypothesized that HASparticipants would remember anxiety and threat-relatedinformation better than LAS participants and thatphysiological arousal would enhance this difference. Support for the first hypothesis was limited.Anxiety sensitivity did

Randi E. Mccabe

1999-01-01

221

High-speed polarization-sensitive optical coherence tomography for the investigation of tissue birefringence  

Microsoft Academic Search

Polarization-sensitive optical coherence tomography (PSOCT) is an optical imaging modality that is sensitive to the birefringence properties of tissues. Birefringence is related to various biological components and therefore, polarization can provide novel contrast mechanisms for imaging. In this work, we will describe the design of a high-speed polarization sensitive optical coherence tomography system. A broadband source centered at 1310nm with

Gultekin Gulsen; Orhan Nalcioglu

2005-01-01

222

Highly Sensitive and Easy-to-Use SQUID Sensors  

Microsoft Academic Search

We have developed a novel family of low-noise superconducting quantum interference devices (SQUIDs) to cover a wide range of applications. These sensors are robust and easy to use without compromising noise performance. They are optimized for operation with our high-speed direct-coupled flux-locked loop (FLL) electronics XXF-1. For the readout of cryogenic detectors, series arrays of 16 SQUIDs with 3 nH

D.. Drung; C.. Assmann; J.. Beyer; A.. Kirste; M.. Peters; F.. Ruede; T.. Schurig

2007-01-01

223

Dynamics and sensitivity analysis of high frequency conduction block  

PubMed Central

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) That depolarizing currents promote conduction block via inactivation of sodium channels, and 2) that 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 too slow to track the high frequency changes in membrane potential during HFS, and that the behavior of the fast sodium current was dominated by the low frequency depolarization of the membrane. As a result, in the blocked state, only 5.4% of nodal sodium channels were found to be in the activatable state in the node closest to the blocking electrode, resulting in a conduction block. Moreover, we find that the corner frequency for the persistent sodium channel activation gate corresponds to the frequency below which high frequency stimuli of arbitrary amplitude are incapable of inducing conduction block. PMID:22056338

Ackermann, D. Michael; Bhadra, Niloy; Gerges, Meana; Thomas, Peter J.

2012-01-01

224

Detecting hybridization of DNA by highly sensitive evanescent field etched core fiber Bragg grating sensors  

Microsoft Academic Search

Highly sensitive fiber Bragg grating sensors were developed by etching away the cladding and part of the core of the fiber and detecting the change of Bragg wavelength due to the change of index of the surrounding medium. A sensitivity of 1394 nm\\/riu was achieved when the diameter of the grating core was 3.4 ?m and the index of the

Athanasios N. Chryssis; Simarjeet S. Saini; Sang M. Lee; Hyunmin Yi; William E. Bentley; Mario Dagenais

2005-01-01

225

Assessing the intercultural sensitivity of high school students attending an international school  

Microsoft Academic Search

The purpose of this exploratory study was to measure the level of intercultural sensitivity (ICS) of high school students attending an international school. ICS was defined as sensitivity to the importance of cultural differences and to the points of view of people in other cultures (Int. J. Intercultural Relat. 16(4) (1992) 413). Students ranged in age from 13 to 19

David A Straffon

2003-01-01

226

3D Brownian Motion Simulator for High-Sensitivity Nano-Biotechnological  

E-print Network

3D Brownian Motion Simulator for High-Sensitivity Nano-Biotechnological Applications ´Arp´ad T of the nanoparticles involved. Results: We present a three-dimensional Brownian motion simulation tool-sensitivity applications in molecular recognition need the reliable mod- elling of the Brownian motion of the nanoparticles

Grolmusz, Vince

227

A high- trans fatty acid diet and insulin sensitivity in young healthy women  

Microsoft Academic Search

Epidemiological and experimental studies suggest that a diet rich in saturated fat affects insulin sensitivity. Monoenes and dienes that have an usaturated bond with the trans configuration (trans fatty acids) resemble saturated fatty acids with respect to structure, but no published data are available on the effect of trans fatty acids on insulin sensitivity. Therefore, the effects of diets high

Anne M. Louheranta; Anu K. Turpeinen; Helvi M. Vidgren; Ursula S. Schwab; Matti I. J. Uusitupa

1999-01-01

228

A highly sensitive and selective fluorescent chemosensor for Pb2+ ions in an aqueous solution.  

PubMed

A new fluorescent sensor based on the BODIPY fluorophore and the polyamide receptor for Pb(2+) was designed and synthesized. The sensor is highly selective for Pb(2+) over relevant competing metal ions, and sensitive to ppb levels of Pb(2+). It features the most sensitive probe to date for Pb(2+) ions in water. PMID:23319008

Liu, Jing; Wu, Kai; Li, Sha; Song, Tao; Han, Yifeng; Li, Xin

2013-03-21

229

Sensitivity of the thermohaline circulation to tropical and high latitude freshwater forcing during the last  

E-print Network

Sensitivity of the thermohaline circulation to tropical and high latitude freshwater forcing during thermohaline circulation (THC). Here we present a sensitivity study in which we use a model scenario for ENSOIntyre, 1981]. Broecker and Denton [1989] argued that changes in North Atlantic thermohaline circulation (THC

Schmittner, Andreas

230

"Ultra-high resolution optical trap with single fluorophore sensitivity"  

PubMed Central

We present a single-molecule instrument that combines a timeshared ultra-high resolution dual optical trap interlaced with a confocal fluorescence microscope. In a demonstration experiment, individual single-fluorophore labeled DNA oligonucleotides were observed to bind and unbind to complementary DNA suspended between two trapped beads. Simultaneous with the single-fluorophore detection, coincident angstrom-scale changes in tether extension could be clearly observed. Fluorescence readout allowed us to determine the duplex melting rate as a function of force. The new instrument will enable the simultaneous measurement of angstrom-scale mechanical motion of individual DNA-binding proteins (e.g., single base pair stepping of DNA translocases) along with the detection of fluorescently labeled protein properties (e.g., internal configuration). PMID:21336286

Comstock, Matthew J; Ha, Taekjip; Chemla, Yann R

2013-01-01

231

Highly Sensitive Nanoparticle-based Multifunctional Biosensor for Antigen Detection  

NASA Astrophysics Data System (ADS)

Precise and selective positioning of nanoparticles gives rise to many applications where assembly of nano building blocks with different biological or chemical functionalization is necessary. One remarkable application is the simultaneous early detection of multiple biomarkers in the field of miniaturized multiplex biosensors. To enable multiplex detection of antigens, nanoparticles with various antibody coatings can be selectively assembled in trenches on different regions on a biochip so that they bind selectively to the specific antigen of interest. The presented work utilizes electric field assisted assembly techniques to assemble nanoparticles with various surface functionalization and coatings. Nanoparticles are assembled into pre-fabricated via and trench patterns generated on a PMMA coated gold surface, using electron-beam lithography. Two techniques have been developed for selective assembly of nanoparticles: sequential size-selective directed assembly and sequential site-selective assembly. Both selective assembly techniques provide fast and reproducible assembly over large areas while achieving high yield. The sequential size-selective assembly is a template-assisted technique where the selectivity is achieved by controlling the size of the nanopatterns and the size of the nanoparticles. The possibility of particle detachment and the factors affecting the sorting efficiency for this technique is studied. We show that a complete sorting can be achieved when the size of the vias is close to the diameter of the nanoparticles and the size distribution of the chosen nanoparticles do not overlap. In the site-selective assembly, the selectivity is achieved by having electrically isolated sites (regions) on the same chip. Electrophoresis is performed for each region in a step by step process. Selective assembly results, for up to four nanoparticles with various coating/functionalization are presented using the site-selective assembly technique. We use the electrophoresis technique to assemble the cancer specific anti-PSA, mAb-2C5 and CEA coated nanoparticles to show that the nanoparticle-based biochip can successfully measure low concentrations of various antigen. The principle of operation of these biosensors is the fluorescence based ELISA. Testing results of the nanoparticle-based biochips indicate very high specificity and the detection limit 200 times smaller than the commercially available devices for antigen detection, laying the foundation for early detection of various diseases. The optimized assembly of antibody coated particles and selective assembly techniques introduced in this work provide the necessary tools for fabricating a miniaturized nanoparticle-based in-vivo multiplex biosensor. The antigen detection results show the great potential for early detection of various diseases using the fabricated in-vivo device.

Siavoshi, Salome

232

High sensitivity microchannel plate detectors for space extreme ultraviolet missions  

NASA Astrophysics Data System (ADS)

Microchannel plate (MCP) detectors have been widely used as two-dimensional photon counting devices on numerous space EUV (extreme ultraviolet) missions. Although there are other choices for EUV photon detectors, the characteristic features of MCP detectors such as their light weight, low dark current, and high spatial resolution make them more desirable for space applications than any other detector. In addition, it is known that the photocathode can be tailored to increase the quantum detection efficiency (QDE) especially for longer UV wavelengths (100-150 nm). There are many types of photocathode materials available, typically alkali halides. In this study, we report on the EUV (50-150 nm) QDE evaluations for MCPs that were coated with Au, MgF2, CsI, and KBr. We confirmed that CsI and KBr show 2-100 times higher QDEs than the bare photocathode MCPs, while Au and MgF2 show reduced QDEs. In addition, the optimal geometrical parameters for the CsI deposition were also studied experimentally. The best CsI thickness was found to be 150 nm, and it should be deposited on the inner wall of the channels only where the EUV photons initially impinge. We will also discuss the techniques and procedures for reducing the degradation of the photocathode while it is being prepared on the ground before being deployed in space, as adopted by JAXA's EXCEED mission which will be launched in 2013.

Yoshioka, K.; Homma, T.; Murakami, G.; Yoshikawa, I.

2012-08-01

233

BCN Nanotubes as Highly Sensitive Torsional Electromechanical Transducers.  

PubMed

Owing to their mechanically tunable electronic properties, carbon nanotubes (CNTs) have been widely studied as potential components for nanoelectromechanical systems (NEMS); however, the mechanical properties of multiwall CNTs are often limited by the weak shear interactions between the graphitic layers. Boron nitride nanotubes (BNNTs) exhibit a strong interlayer mechanical coupling, but their high electrical resistance limits their use as electromechanical transducers. Can the outstanding mechanical properties of BNNTs be combined with the electromechanical properties of CNTs in one hybrid structure? Here, we report the first experimental study of boron carbonitride nanotube (BCNNT) mechanics and electromechanics. We found that the hybrid BCNNTs are up to five times torsionally stiffer and stronger than CNTs, thereby retaining to a large extent the ultrahigh torsional stiffness of BNNTs. At the same time, we show that the electrical response of BCNNTs to torsion is 1 to 2 orders of magnitude higher than that of CNTs. These results demonstrate that BCNNTs could be especially attractive building blocks for NEMS. PMID:25275220

Garel, Jonathan; Zhao, Chong; Popovitz-Biro, Ronit; Golberg, Dmitri; Wang, Wenlong; Joselevich, Ernesto

2014-11-12

234

Confidence Level and Sensitivity Limits in High Contrast Imaging  

SciTech Connect

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3 x 10{sup -7} confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

Marois, C; LaFreniere, D; Macintosh, B; Doyon, R

2008-06-02

235

Confidence Level and Sensitivity Limits in High Contrast Imaging  

SciTech Connect

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground and space-based telescopes. Previous theoretical analysis have shown that the time intensity variations of a single speckle follows a modified Rician. It is first demonstrated here that for a circular pupil this temporal intensity distribution also represents the speckle spatial intensity distribution at a fix separation from the point spread function center; this fact is demonstrated using numerical simulations for coronagraphic and non-coronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level. In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding confidence level as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckles noise, a detection threshold up to three times higher is required to obtain a confidence level equivalent to that at 5{sigma} for Gaussian noise. The technique is then tested using TRIDENT CFHT and angular differential imaging NIRI Gemini adaptive optics data. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. A power-law is finally derived to predict the 1-3 x 10{sup -7} confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

Marois, C

2007-11-07

236

Confidence Level and Sensitivity Limits in High-Contrast Imaging  

NASA Astrophysics Data System (ADS)

In long adaptive optics corrected exposures, exoplanet detections are currently limited by speckle noise originating from the telescope and instrument optics, and it is expected that such noise will also limit future high-contrast imaging instruments for both ground- and space-based telescopes. Previous theoretical analyses have shown that the time intensity variations of a single speckle follow a modified Rician. It is first demonstrated here that for a circular pupil, this temporal intensity distribution also represents the speckle spatial intensity distribution at a fixed separation from the point-spread function center; this fact is demonstrated using numerical simulations for coronagraphic and noncoronagraphic data. The real statistical distribution of the noise needs to be taken into account explicitly when selecting a detection threshold appropriate for some desired confidence level (CL). In this paper, a technique is described to obtain the pixel intensity distribution of an image and its corresponding CL as a function of the detection threshold. Using numerical simulations, it is shown that in the presence of speckle noise, a detection threshold up to 3 times higher is required to obtain a CL equivalent to that at 5 ? for Gaussian noise. The technique is then tested on data acquired by simultaneous spectral differential imaging with TRIDENT and by angular differential imaging with NIRI. It is found that the angular differential imaging technique produces quasi-Gaussian residuals, a remarkable result compared to classical adaptive optic imaging. Finally, a power law is derived to predict the 1-310-7 CL detection threshold when averaging a partially correlated non-Gaussian noise. Based on observations obtained at the Canada-France-Hawaii Telescope (CFHT), which is operated by the National Research Council of Canada, the Institut National des Sciences de l'Univers of the Centre National de la Recherche Scientifique of France, and the University of Hawaii. Also based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).

Marois, Christian; Lafrenire, David; Macintosh, Bruce; Doyon, Ren

2008-01-01

237

HIGH SENSITIVITY FOURIER TRANSFORM NMR. INTERMOLECULAR INTERACTIONS BETWEEN ENVIRONMENTAL TOXIC SUBSTANCES AND BIOLOGICAL MACROMOLECULES  

EPA Science Inventory

This project explored the feasibility of developing new techniques for evaluation of the effects of environmental toxic materials on complex biopolymer systems using high sensitivity Fourier transform nuclear magnetic resonance (nmr) spectroscopy. Commercial instrumentation avail...

238

High-Sensitivity Optical Monitoring of a Micromechanical Resonator with a Quantum-Limited Optomechanical Sensor  

Microsoft Academic Search

We experimentally demonstrate the high-sensitivity optical monitoring of a micromechanical resonator and its cooling by active control. Coating a low-loss mirror upon the resonator, we have built an optomechanical sensor based on a very high-finesse cavity (30 000). We have measured the thermal noise of the resonator with a quantum-limited sensitivity at the 10-19m\\/Hz level, and cooled the resonator down

O. Arcizet; P.-F. Cohadon; T. Briant; M. Pinard; A. Heidmann; J.-M. Mackowski; C. Michel; L. Pinard; O. Franais; L. Rousseau

2006-01-01

239

Highly Sensitive Determination of Hydrogen Peroxide and Glucose by Fluorescence Correlation Spectroscopy  

Microsoft Academic Search

BackgroundBecause H2O2 is generated by various oxidase-catalyzed reactions, a highly sensitive determination method of H2O2 is applicable to measurements of low levels of various oxidases and their substrates such as glucose, lactate, glutamate, urate, xanthine, choline, cholesterol and NADPH. We propose herein a new, highly sensitive method for the measurement of H2O2 and glucose using fluorescence correlation spectroscopy (FCS).Methodology\\/Principal FindingsFCS

Satoshi Watabe; Yuki Sakamoto; Mika Morikawa; Ryuichi Okada; Toshiaki Miura; Etsuro Ito

2011-01-01

240

Monte Carlo study of a high-sensitivity gamma-ray detection system  

SciTech Connect

The authors use Monte Carlo calculations to study a new design for a high-sensitivity gamma-ray detection system. The system uses an array of high-purity germanium detectors operating with an event-mode data acquisition system. The calculations show that the proposed design could produce a factor of 10 increase in the sensitivity of these measurements compared to currently employed systems.

Decman, D.J.; Namboodiri, M.N.

1995-03-01

241

Highly sensitive refractometer with a photonic-crystal-fiber long-period grating.  

PubMed

We present highly sensitive refractometers based on a long-period grating in a large-mode-area photonic crystal fiber (PCF). The maximum sensitivity is 1500 nm/refractive index unit at a refractive index of 1.33, to our knowledge the highest reported for any fiber grating. The minimal detectable index change is 2 x 10(-5). The high sensitivity is obtained by infiltrating the sample into the holes of the PCF to give a strong interaction between the sample and the probing field. PMID:18347710

Rindorf, Lars; Bang, Ole

2008-03-15

242

Highly Sensitive Terahertz Sensing of Glycerol-Water Mixtures with Metamaterials  

NASA Astrophysics Data System (ADS)

We demonstrate the highly sensitive terahertz (THz) sensing of a water-glycerol mixture poured on a metamaterial surface using reflection-based THz time domain spectroscopy. The reflectance at the resonant dip frequency changes significantly with glycerol concentration. The detection sensitivity is about 8 times higher than that compared to the case without a metamaterial structure. We also investigate how sensitivity depends on the Q factor of the metamaterial resonance for highly absorptive media, such as a water solution in the THz region.

Miyamaru, F.; Hattori, K.; Shiraga, K.; Kawashima, S.; Suga, S.; Nishida, T.; Takeda, M. W.; Ogawa, Y.

2013-11-01

243

A Fabry-Perot cuboid cavity across the fibre for high-sensitivity strain force sensing  

NASA Astrophysics Data System (ADS)

A Fabry-Perot interferometer (FPI) cuboid cavity across the fibre for strain force sensing with high sensitivity is proposed and investigated. Theoretical simulations and calculation results based on the method of static mechanics analysis showed that the sensitivity of an FPI cuboid cavity across the fibre with a smaller cavity length is better than that of FPI cavities with other shapes. Then two FPI cuboid cavities across the fibres with the sizes of 18 60 ?m and 15 60 ?m were fabricated using a femtosecond laser micromachine followed by fibre fusion. Their strain force sensitivities reached as high as 21.95 nm N-1 (18.9 pm/??) and 26.10 nm N-1 (22.5 pm/??). The experimental results agree well with the theoretical analysis and simulation. The FPI cuboid cavities across the fibres can be used as strain force sensors because of their high sensitivity, good temperature-insensitive characteristics, miniature size and simple fabrication.

Liu, Yi; Qu, Shiliang; Qu, Wenge; Que, Ruyue

2014-10-01

244

High-sensitivity temperature sensor based on a droplet-like fiber circle.  

PubMed

A low-cost yet high-sensitivity temperature fiber sensor is proposed and demonstrated in this paper. A single-mode fiber with coating is simply bent in a droplet-like circle with a radius of several millimeters. The strong bending induces mode interferences between the silica core mode and the excited modes propagating in the polymer coating. Many resonant dips were observed in the transmission spectra and are found to shift to a shorter wavelength with the increase of environmental temperature. Our linear fitting result of the experimental data shows that the proposed sensor presents high temperature sensitivity up to -3.102??nm/C, which is even comparable with sensors based on selective liquid-filled photonic crystal fibers. Such high temperature sensitivity results from the large thermo-optical coefficient difference between the silica core and the polymer coating. The influence of a circle radius to the sensitivities is also discussed. PMID:24979444

Xie, Jianglei; Xu, Ben; Li, Yi; Kang, Juan; Shen, Changyu; Wang, Jianfeng; Jin, Yongxing; Liu, Honglin; Ni, Kai; Dong, Xinyong; Zhao, Chunliu; Jin, Shangzhong

2014-06-20

245

Highly sensitive potentiometric strip test for detecting high charge density impurities in heparin.  

PubMed

Contamination of heparin with oversulfated chondroitin sulfate (OSCS) became a matter of grave concern in the medical field after many fatal responses to OSCS tainted heparin products occurred during the 2007-2008 period. Even though standard lab-based analytical techniques such as nuclear magnetic resonance (NMR) and strong anion-exchange high performance liquid chromatography (SAX-HPLC) have proven useful for monitoring the OSCS content in heparin products, an easy-to-use, quick, portable, and cost-efficient method is still needed for on-site monitoring during and after the heparin production. In this report, a disposable strip-type electrochemical polyion sensor is described for detection of low levels of OSCS contamination in heparin. A magnetic actuator is incorporated into this simple electrode-based microfluidic device in order to create the mixing effect necessary to achieve equilibrium potential changes of the sensor within a microfluidic channel. The planar membrane electrode detector within the sample channel is prepared with a tridodecylmethylammonium chloride (TDMAC)-doped poly(vinyl chloride) (PVC) membrane essentially equivalent to previously reported polyanion-sensitive electrodes. When the concentration of heparin applied to the single-use strip device is 57 mg/mL (in only 20 ?L of sample), the same concentration recommended in the NMR analysis protocol for detecting OSCS in heparin, the detection limit is 0.005 wt % of OSCS, which is ca. 20 times lower than the reported detection limit of the NMR method. PMID:21500820

Kang, Youngjea; Gwon, Kihak; Shin, Jae Ho; Nam, Hakhyun; Meyerhoff, Mark E; Cha, Geun Sig

2011-05-15

246

Highly sensitive electronic whiskers based on patterned carbon nanotube and silver nanoparticle composite films.  

PubMed

Mammalian whiskers present an important class of tactile sensors that complement the functionalities of skin for detecting wind with high sensitivity and navigation around local obstacles. Here, we report electronic whiskers based on highly tunable composite films of carbon nanotubes and silver nanoparticles that are patterned on high-aspect-ratio elastic fibers. The nanotubes form a conductive network matrix with excellent bendability, and nanoparticle loading enhances the conductivity and endows the composite with high strain sensitivity. The resistivity of the composites is highly sensitive to strain with a pressure sensitivity of up to ?8%/Pa for the whiskers, which is >10 higher than all previously reported capacitive or resistive pressure sensors. It is notable that the resistivity and sensitivity of the composite films can be readily modulated by a few orders of magnitude by changing the composition ratio of the components, thereby allowing for exploration of whisker sensors with excellent performance. Systems consisting of whisker arrays are fabricated, and as a proof of concept, real-time two- and three-dimensional gas-flow mapping is demonstrated. The ultrahigh sensitivity and ease of fabrication of the demonstrated whiskers may enable a wide range of applications in advanced robotics and human-machine interfacing. PMID:24449857

Takei, Kuniharu; Yu, Zhibin; Zheng, Maxwell; Ota, Hiroki; Takahashi, Toshitake; Javey, Ali

2014-02-01

247

Calibration of the high sensitivity shadow moir system using random phase-shifting technique  

NASA Astrophysics Data System (ADS)

In high sensitivity shadow moir, the small Talbot distance limits the dynamic range. In this case, if the phase shift is introduced by object translation in its own plane, the object may be out of the dynamic range. The result is rapid changes in the period of fringe pattern. So problems arise when Dirckx' way is used to calibrate the fringe distance (or the sensitivity). In the presented paper, we describe a solution to solve the problem. The proposed method based on the idea of random phase shifting technique, which can extract the measurement phase not requiring a previous knowledge of the exact phase shift, and the sensitivity can be calibrated during the process of phase demodulation. Besides, the proposed method can provide an exact close-form result for the sensitivity. Simulations and optical experiments are implemented to verify the effectiveness of this method. The proposed method is suitable for the calibration of the sensitivity in phase shift shadow moir.

Du, Hubing; Wang, Jianhua; Zhao, Hong; Jia, Pingping

2014-12-01

248

Is sensitivity to reward associated with the malleability of implicit inclinations toward high-fat food?  

PubMed

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. PMID:23527505

Ashby, Casey R; Stritzke, Werner G K

2013-08-01

249

Sensitivity of downward longwave surface radiation to humidity and clouds at a high elevation site  

NASA Astrophysics Data System (ADS)

This study investigates why some high elevation regions can experience greater rates of warming than their lower elevation surroundings. We focus on the combined effects of specific humidity (q) and clouds on the surface downward longwave radiation (DLR). Using 6-years of ground-based observations at two nearby high-elevation sites in the San Juan Mountains in southwestern Colorado, we investigate the sensitivity of DLR to changes in q. We find that the sensitivity of DLR to changes in q is much greater when the atmosphere is dry, and these conditions tend to occur at higher elevations during winter. In addition, we use satellite-derived cloud properties to examine how the sensitivity is affected by changes in cloud cover and optical thickness. Although DLR increases with increasing cloud cover, both a simple regression and a neural network analysis indicate that clouds have a small effect on the sensitivity of DLR to q, mostly a reduction that increases with increasing q. Changes in cloud fraction have a larger impact on DLR for large cloud fractions, but have less impact on changes in DLR than changes in humidity. In the limit of overcast clouds, DLR is sensitive to changes in optical thickness only when clouds are optically thin, otherwise the sensitivity of DLR to optical thickness is negligible. We discuss differences between nighttime and daytime sensitivities at two nearby sites, as well as the generality of our results.

Chen, Y.; Naud, C. M.; Rangwala, I.; Miller, J. R.

2013-12-01

250

Highly sensitive fiber refractive index sensor based on side-core holey structure  

NASA Astrophysics Data System (ADS)

We propose a side-core holey fiber (SCHF)-based surface plasmon resonance (SPR) sensor to achieve high refractive index (RI) sensitivity. The SCHF structure can facilitate analyte filling and enhance the overlapping area of the core mode and surface plasmon polariton (SPP) mode. The coupling properties of the sensor are analyzed by numerical simulation. The maximum sensitivity of 5000 nm/RIU in an RI range of 1.331.44, and the average sensitivity of 9295 nm/RIU in an RI range from 1.44 to 1.54 can be obtained.

Han, Ya; Xia, Li; Liu, De-Ming

2014-10-01

251

High sensitivity molecular detection with enzyme-linked immuno-sorbent assay (ELISA)-type immunosensing  

NASA Astrophysics Data System (ADS)

Here we describe an immunosensing method, which is designed for high sensitivity sensing of various substances utilizing specificity of antigen-antibody (ELISA-type) interaction. The building up of the nanostructured sensing interface and the immunointeraction at the surface were characterized by atomic force microscopy. The proposed design makes potentially feasible attaining ultimate single-molecule sensitivity upon optimization of the system. The first non-optimized prototype described here has already demonstrated sensitivity to the presence of dinitrophenyl (DNP) in concentrations as low as 10 pM, which is 100 times better than reported limits of detection of DNP with a traditional enzyme-linked immuno-sorbent assay setup.

Pita, Marcos; Cui, Lili; Gaikwad, Ravi M.; Katz, Evgeny; Sokolov, Igor

2008-09-01

252

Highly asymmetrical porphyrins with enhanced push-pull character for dye-sensitized solar cells.  

PubMed

A porphyrin ?-system has been modulated by enhancing the push-pull character with highly asymmetrical substitution for dye-sensitized solar cells for the first time. Namely, both two diarylamino moieties as a strong electron-donating group and one carboxyphenylethynyl moiety as a strong electron-withdrawing, anchoring group were introduced into the meso-positions of the porphyrin core in a lower symmetrical manner. As a result of the improved light-harvesting property as well as high electron distribution in the anchoring group of LUMO, a push-pull-enhanced, porphyrin-sensitized solar cell exhibited more than 10% power conversion efficiency, which exceeded that of a representative highly efficient porphyrin (i.e., YD2)-sensitized solar cell under optimized conditions. The rational molecular design concept based on highly asymmetric, push-pull substitution will open the possibilities of further improving cell performance in organic solar cells. PMID:24227165

Kurotobi, Kei; Toude, Yuuki; Kawamoto, Kyosuke; Fujimori, Yamato; Ito, Seigo; Chabera, Pavel; Sundstrm, Villy; Imahori, Hiroshi

2013-12-01

253

Ultra high vacuum pumping system and high sensitivity helium leak detector  

Microsoft Academic Search

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

Myneni; Ganapati Rao

1997-01-01

254

High-sensitivity cytometric detection using fluidic-photonic integrated circuits with array waveguides  

Microsoft Academic Search

We demonstrate a new detection scheme for a microfabricated flow cytometer. The fluidic-photonic integrated circuits (FPICs) that perform flow cytometric detection possess new functionality, such as on-chip excitation, time-of-flight measurement, and above all, greatly enhanced fluorescence detection sensitivity. Using the architecture of space-division waveguide demultiplexer and the technique of cross-correlation analysis, we obtained high detection sensitivity with a simple light

Victor Lien; Kai Zhao; Yevgeny Berdichevsky; Yu-Hwa Lo

2005-01-01

255

Anomalous Strain Rate Sensitivity of Twinning in a Magnesium Alloy at High Temperature  

NASA Astrophysics Data System (ADS)

Anomalous strain rate sensitivity of twinning was observed in a Mg-Al-Mn magnesium alloy during extrusion around 723 K (450 C). The density of twins decreases as the ram speed increases. At 10 mm min-1, relatively high density twins are activated, but much fewer twins were observed at 30 mm min-1; at 50 mm min-1, twins were hardly seen. The negative strain rate sensitivity was ascribed to the interaction of twinning with defects.

Ma, Quancang; Li, Bin; Mcclelland, Zackery; Horstemeyer, Stephen J.

2013-10-01

256

Design of a high-sensitivity DVB-T system using dual receivers and silicon tuners  

Microsoft Academic Search

In this paper we design a high-sensitivity DVB-T (digital video broadcasting-terrestrial) system using dual receivers and silicon tuners. We have modified and utilized two receivers in our front end, each integrated with a tuner by using an OFDM (orthogonal frequency division multiplexing) structure to demodulate the receiving signal. Dual receivers compensate each other and improve the sensitivity of the DVB-T

Ying-Wen Bai; Wei-Shen Lai

2009-01-01

257

Mechanism of highly sensitive and fast response Cr doped TiO 2 oxygen gas sensor  

Microsoft Academic Search

The recent trend in the field of gas sensor research is to develop new sensing materials with higher sensitivity, selectivity and shorter response time. Titania (TiO2) doped with chromium has been investigated for its oxygen sensing properties. At an optimum Cr concentration of 0.4 wt.% the sensor shows a high sensitivity and shorter response time at 700C as compared to

Rajnish K Sharma; M. C Bhatnagar; G. L Sharma

1997-01-01

258

Highly efficient photon-to-electron conversion with mercurochrome-sensitized nanoporous oxide semiconductor solar cells  

Microsoft Academic Search

Dye-sensitized solar cells based on nanoporous oxide semiconductor thin films such as TiO2, Nb2O5, ZnO, SnO2, and In2O3 with mercurochrome as the sensitizer were investigated. Photovoltaic performance of the solar cell depended remarkably on the semiconductor materials. Mercurochrome can convert visible light in the range of 400600nm to electrons. A high incident photon-to-current efficiency (IPCE), 69%, was obtained at 510nm

Kohjiro Hara; Takaro Horiguchi; Tohru Kinoshita; Kazuhiro Sayama; Hideki Sugihara; Hironori Arakawa

2000-01-01

259

Multiple probing-based microwave methods for highly sensitive measurement of nonelectrical quantities  

Microsoft Academic Search

Design principles of highly sensitive microwave measuring devices with waveguide\\/waveguide resonator sensors of nonelectrical quantities are proposed. These sensors contain passive microwave components for controlling propagation characteristics of guided microwaves. Such sensors are characterized by increased measurement accuracy and sensor sensitivity to measured parameters in comparison with prototypes without such components. Examples of schemes for separate single\\/multiple interaction of oppositely-directed

A. S. Sovlukov; T. Varpula

2006-01-01

260

Implicit associations between anxiety-related symptoms and catastrophic consequences in high anxiety sensitive individuals  

Microsoft Academic Search

Anxiety sensitivity refers to the fear of anxiety-related physical sensations arising from beliefs that these sensations have harmful consequences (Reiss & McNally, 1985). The present study examined whether individuals with high (vs. low) anxiety sensitivity show stronger implicit associations in memory between anxiety-related symptoms, as opposed to neutral body parts, and harmful, as compared to harmless, consequences. A total of

Margo C. Watt; Sherry H. Stewart; Kristi D. Wright

2006-01-01

261

Highly sensitive and selective fluorometric/electrochemical dual-channel sensors for TNT and DNT explosives.  

PubMed

A novel electro-active compound, TCAC, is synthesized and its electrochemical polymerized film is used to detect 2,4,6-trinitrotoluene (TNT) and 2,4-dinitrotoluene (DNT) explosives through a fluorometric/electrochemical dual-channel sensor with high sensitivity and selectivity. In particular, the electrochemical sensor for the analysis of TNT had an enhanced sensitivity of 0.5??M. The detection limit of the sensor was calculated to be 15?nM. PMID:25070924

Ma, Hongwei; Yao, Liang; Li, Peng; Ablikim, Obolda; Cheng, Yunfei; Zhang, Ming

2014-09-01

262

Highly sensitive carbon nanotube-embedding gas sensors operating at atmospheric pressure  

Microsoft Academic Search

Highly sensitive palladium (Pd) decorated carbon nanotube (CNT) embedding gas sensors working at atmospheric pressure were fabricated. Two types of gas sensors of bare CNTs and Pd nanoparticle decorated CNTs were synthesized by dielectrophoresis. The CNT-containing solution was dropped onto the patterned-platinum electrodes with ac bias. The CNT-embedding sensors sensitively detected 100 ppb level of NO2 in an atmospheric pressure

Ju-Hyung Yun; Joondong Kim; Yun Chang Park; Jin-Won Song; Dong-Hun Shin; Chang-Soo Han

2009-01-01

263

Identification of Three Subunits of the High Affinity -Conotoxin MVIIC-sensitive Ca2  

E-print Network

Identification of Three Subunits of the High Affinity -Conotoxin MVIIC-sensitive Ca2 Channel MVIIC. In this study, both a high affinity and a low affinity binding site for -conotoxin MVIIC were detected in rabbit brain. The low affinity binding site is shown to be present on the N-type Ca2 channel

Campbell, Kevin P.

264

Highly sensitive electronic whiskers based on patterned carbon nanotube and silver nanoparticle  

E-print Network

composite films of carbon nanotubes and silver nanoparticles that are patterned on high-aspect-ratio elasticHighly sensitive electronic whiskers based on patterned carbon nanotube and silver nanoparticle composite films Kuniharu Takei1,2 , Zhibin Yu1 , Maxwell Zheng, Hiroki Ota, Toshitake Takahashi, and Ali

Javey, Ali

265

Z - R relation for snowfall using small Doppler radar and high sensitive snow gauges  

Microsoft Academic Search

Snowfall data was simultaneously recorded by a weather radar, two high sensitive snow gauges and an imaging system with high accuracy at short time intervals. The snowfall rate R was measured with two gauges and radar reflectivity factor Z was measured using a small bistatic X-band Doppler radar. The images of falling snow particles were used to obtain size and

M. Kubo; A. Sougen; K. Muramoto; Y. Fujiyoshi

2009-01-01

266

Image quality and dose efficiency of high energy phase sensitive x-ray imaging: Phantom studies  

PubMed Central

The goal of this preliminary study was to perform an image quality comparison of high energy phase sensitive imaging with low energy conventional imaging at similar radiation doses. The comparison was performed with the following phantoms: American College of Radiology (ACR), contrast-detail (CD), acrylic edge and tissue-equivalent. Visual comparison of the phantom images indicated comparable or improved image quality for all phantoms. Quantitative comparisons were performed through ACR and CD observer studies, both of which indicated higher image quality in the high energy phase sensitive images. The results of this study demonstrate the ability of high energy phase sensitive imaging to overcome existing challenges with the clinical implementation of phase contrast imaging and improve the image quality for a similar radiation dose as compared to conventional imaging near typical mammography energies. In addition, the results illustrate the capability of phase sensitive imaging to sustain the image quality improvement at high x-ray energies and for breast simulating phantoms, both of which indicate the potential to benefit fields such as mammography. Future studies will continue to investigate the potential for dose reduction and image quality improvement provided by high energy phase sensitive contrast imaging. PMID:24865208

Wong, Molly Donovan; Wu, Xizeng; Liu, Hong

2014-01-01

267

Ultrasensitive UPLC-MS-MS Method for the Quantitation of Etheno-DNA Adducts in Human Urine.  

PubMed

Etheno-DNA adducts are generated from the metabolism of exogenous carcinogens and endogenous lipid peroxidation. We and others have previously reported that 1,N6-ethenodeoxyadenosine (?dA) and 3,N4-ethenodeoxycytidine (?dC) are present in human urine and can be utilized as biomarkers of oxidative stress. In this study, we report a new ultrasensitive UPLC-ESI-MS/MS method for the analysis of ?dA and edC in human urine, capable of detecting 0.5 fmol ?dA and 0.3 fmol ?dC in 1.0 mL of human urine, respectively. For validation of the method, 20 human urine samples were analyzed, and the results revealed that the mean levels of ?dA and ?dC (SD) fmol/mol creatinine are 5.82 2.11 (range 3.0-9.5) for ?dA and 791.4 328.8 (range 116.7-1264.9) for ?dC in occupational benzene-exposed workers and 2.10 1.32 (range 0.6-4.7) for ?dA and 161.8 200.9 (range 1.8-557.5) for ?dC in non-benzene-exposed workers, respectively. The ultrasensitive detection method is thus suitable for applications in human biomonitoring and molecular epidemiology studies. PMID:25337939

Cui, Shiwei; Li, Haibin; Wang, Shaojia; Jiang, Xiao; Zhang, Shusheng; Zhang, Rongjie; Sun, Xin

2014-01-01

268

Ultrasensitive UPLC-MS-MS Method for the Quantitation of Etheno-DNA Adducts in Human Urine  

PubMed Central

Etheno-DNA adducts are generated from the metabolism of exogenous carcinogens and endogenous lipid peroxidation. We and others have previously reported that 1,N6-ethenodeoxyadenosine (?dA) and 3,N4-ethenodeoxycytidine (?dC) are present in human urine and can be utilized as biomarkers of oxidative stress. In this study, we report a new ultrasensitive UPLC-ESI-MS/MS method for the analysis of ?dA and ?dC in human urine, capable of detecting 0.5 fmol ?dA and 0.3 fmol ?dC in 1.0 mL of human urine, respectively. For validation of the method, 20 human urine samples were analyzed, and the results revealed that the mean levels of ?dA and ?dC (SD) fmol/mol creatinine are 5.82 2.11 (range 3.09.5) for ?dA and 791.4 328.8 (range 116.71264.9) for ?dC in occupational benzene-exposed workers and 2.10 1.32 (range 0.64.7) for ?dA and 161.8 200.9 (range 1.8557.5) for ?dC in non-benzene-exposed workers, respectively. The ultrasensitive detection method is thus suitable for applications in human biomonitoring and molecular epidemiology studies. PMID:25337939

Cui, Shiwei; Li, Haibin; Wang, Shaojia; Jiang, Xiao; Zhang, Shusheng; Zhang, Rongjie; Sun, Xin

2014-01-01

269

Highly adaptable and sensitive protease assay based on fluorescence resonance energy transfer.  

PubMed

Proteases are widely used in analytical sciences and play a central role in several widespread diseases. Thus, there is an immense need for highly adaptable and sensitive assays for the detection and monitoring of various proteolytic enzymes. We established a simple protease fluorescence resonance energy transfer (pro-FRET) assay for the determination of protease activities, which could in principle be adapted for the detection of all proteases. As proof of principle, we demonstrated the potential of our method using trypsin and enteropeptidase in complex biological mixtures. Briefly, the assay is based on the cleavage of a FRET peptide substrate, which results in a dramatic increase of the donor fluorescence. The assay was highly sensitive and fast for both proteases. The detection limits for trypsin and enteropeptidase in Escherichia coli lysate were 100 and 10 amol, respectively. The improved sensitivity for enteropeptidase was due to the application of an enzyme cascade, which leads to signal amplification. The pro-FRET assay is highly specific as even high concentrations of other proteases did not result in significant background signals. In conclusion, this sensitive and simple assay can be performed in complex biological mixtures and can be easily adapted to act as a versatile tool for the sensitive detection of proteases. PMID:21892820

Zauner, Thomas; Berger-Hoffmann, Renate; Mller, Katrin; Hoffmann, Ralf; Zuchner, Thole

2011-10-01

270

Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon  

NASA Astrophysics Data System (ADS)

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.8B19.2 (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 %/Am-1). 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 %/Am-1) is obtained when the FeCo-based 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.

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

2012-03-01

271

A highly sensitive mean-reverting process in finance and the Euler-Maruyama approximations  

NASA Astrophysics Data System (ADS)

Empirical studies show that the most successful continuous-time models of the short-term rate in capturing the dynamics are those that allow the volatility of interest changes to be highly sensitive to the level of the rate. However, from the mathematics, the high sensitivity to the level implies that the coefficients do not satisfy the linear growth condition, so we can not examine its properties by traditional techniques. This paper overcomes the mathematical difficulties due to the nonlinear growth and examines its analytical properties and the convergence of numerical solutions in probability. The convergence result can be used to justify the method within Monte Carlo simulations that compute the expected payoff of financial productsE For illustration, we apply our results compute the value of a bond with interest rate given by the highly sensitive mean-reverting process as well as the value of a single barrier call option with the asset price governed by this process.

Wu, Fuke; Mao, Xuerong; Chen, Kan

2008-12-01

272

High-sensitive monitoring of carbon monoxide in industry flue gases using tunable diode lasers  

NASA Astrophysics Data System (ADS)

Carbon monoxide (CO) is a very important gas generated in the industrial process; therefore to implement CO concentration on-line monitoring is a key factor for industrial process control. Tunable diode laser absorption spectroscopy (TDLAS) is a high sensitive, high selective and fast trace gas detection technique. With the features of tunability and narrow linewidth of distributed feedback (DFB) laser and by precisely tuning its wavelength to a single isolated absorption line of the gas, TDLAS technique can be utilized to accurately perform online gas concentration monitoring with very high sensitivity. In this paper, a system for online monitoring of CO concentration is developed by our group employing TDLAS technique. The experimental results are present and discussed in this report. The characteristics of the system are: the sensitivity, 10ppm; detection accuracy, 0.02%; long term stability, 1%.

Zhang, Zhi-rong; Dong, Feng-zhong; Xia, Hua; Tu, Guo-jie; Wu, Bian; Wang, Yu

2009-07-01

273

Ultra-high sensitivity photodetector arrays with integrated amplification and passivation nano-layers  

NASA Astrophysics Data System (ADS)

Miniaturized field-deployable spectrometers used for the rapid analysis of chemical and biological substances require high-sensitivity photo detectors. For example, in a Raman spectroscopy system, the receiver must be capable of high-gain, low-noise detection performance due to the intrinsically weak signals produced by the Raman effects of most substances. We are developing a novel, high-gain hetero-junction phototransistor (HPT) detector which employs two nano-structures simultaneously to achieve 100 times higher sensitivity than InGaAs avalanche photodiodes, the most sensitive commercially available photo-detector in the near infrared (NIR) wavelength range, under their normal operation conditions. Integrated into a detector array, this technology has application for Laser-Induced Breakdown Spectroscopy (LIBS), pollution monitoring, pharmaceutical manufacturing by reaction monitoring, chemical & biological transportation safety, and bio-chemical analysis in planetary exploration.

Yao, Jie; Mokina, Irina A.; Liu, Feng; Wang, Sean; Zhou, Jack; Lange, Michael; Yang, Weiguo; Gardner, Patrick; Peltz, Leora; Frampton, Robert; Hunt, Jeffrey H.

2010-02-01

274

Periodically porous top electrodes on vertical nanowire arrays for highly sensitive gas detection  

NASA Astrophysics Data System (ADS)

Nanowires of various materials and configurations have been shown to be highly effective in the detection of chemical and biological species. In this paper, we report a novel, nanosphere-enabled approach to fabricating highly sensitive gas sensors based on ordered arrays of vertically aligned silicon nanowires topped with a periodically porous top electrode. The vertical array configuration helps to greatly increase the sensitivity of the sensor while the pores in the top electrode layer significantly improve sensing response times by allowing analyte gases to pass through freely. Herein, we show highly sensitive detection to both nitrogen dioxide (NO2) and ammonia (NH3) in humidified air. NO2 detection down to 10 parts per billion (ppb) is demonstrated and an order-of-magnitude improvement in sensor response time is shown in the detection of NH3.

In, Hyun Jin; Field, Christopher R.; Pehrsson, Pehr E.

2011-09-01

275

Performance evaluation of the ECAT HRRT: an LSO-LYSO double layer high resolution, high sensitivity scanner  

Microsoft Academic Search

The ECAT high resolution research tomograph (HRRT) is a dedicated brain and small animal PET scanner, with design features that enable high image spatial resolution combined with high sensitivity. The HRRT is the first commercially available scanner that utilizes a double layer of LSO\\/LYSO crystals to achieve photon detection with depth-of-interaction information. In this study, the performance of the commercial

Floris H P van Velden; Reina W Kloet; Fred L Buijs; Ronald Boellaard; Adriaan A Lammertsma

2007-01-01

276

High temperature sensitivity is intrinsic to voltage-gated potassium channels  

PubMed Central

Temperature-sensitive transient receptor potential (TRP) ion channels are members of the large tetrameric cation channels superfamily but are considered to be uniquely sensitive to heat, which has been presumed to be due to the existence of an unidentified temperature-sensing domain. Here we report that the homologous voltage-gated potassium (Kv) channels also exhibit high temperature sensitivity comparable to that of TRPV1, which is detectable under specific conditions when the voltage sensor is functionally decoupled from the activation gate through either intrinsic mechanisms or mutations. Interestingly, mutations could tune Shaker channel to be either heat-activated or heat-deactivated. Therefore, high temperature sensitivity is intrinsic to both TRP and Kv channels. Our findings suggest important physiological roles of heat-induced variation in Kv channel activities. Mechanistically our findings indicate that temperature-sensing TRP channels may not contain a specialized heat-sensor domain; instead, non-obligatory allosteric gating permits the intrinsic heat sensitivity to drive channel activation, allowing temperature-sensitive TRP channels to function as polymodal nociceptors. DOI: http://dx.doi.org/10.7554/eLife.03255.001 PMID:25030910

Yang, Fan; Zheng, Jie

2014-01-01

277

Ultra high vacuum pumping system and high sensitivity helium leak detector  

DOEpatents

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.

Myneni, Ganapati Rao (Yorktown, VA)

1997-01-01

278

Ultra high vacuum pumping system and high sensitivity helium leak detector  

DOEpatents

An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10{sup {minus}13} atm cc/s. 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 back streaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium. 2 figs.

Myneni, G.R.

1997-12-30

279

Alkanethiol-functionalized terahertz metamaterial as label-free, highly-sensitive and specific biosensor.  

PubMed

Specific biorecognition is essential for many biological processes, for which highly sensitive and label-free biosensors are strongly demanded. The recently developed metamaterials are a potential choice for biosensing due to their exotic properties. In the current work, a label-free and specific sensor for streptavidin-agarose (SA) was fabricated based on terahertz metamaterial functionlized by octadecanthiols and biotins. Both low and high frequency resonant modes from the metamaterials are found applicable for the detection of SA, and a redshift up to 6.76 GHz for the high frequency mode was measured in the undiluted commercial solution. The low frequency mode is attributed to inductor-capacitor (LC) oscillation, while the high frequency mode originates from the plasmonic dipole oscillator, both of which are highly sensitive to the micro-environment change. Adsorption of SA of different concentrations causes different redshifts, and the replacement of high refractive-index substrate with low refractive-index substrate can efficiently promote the sensitivity, well agreeing with the numerical simulation. Moreover, for a particular biomolecule, the sensitivity can be further improved by optimizing the metamaterial design. This method might be very helpful for desirable biorecognition in biology, medicine, and drug industry. PMID:23261700

Wu, Xiaojun; Quan, Baogang; Pan, Xuecong; Xu, Xinlong; Lu, Xinchao; Gu, Changzhi; Wang, Li

2013-04-15

280

High-Sensitivity X-ray Polarimetry with Amorphous Silicon Active-Matrix Pixel Proportional Counters  

NASA Technical Reports Server (NTRS)

Photoelectric X-ray polarimeters based on pixel micropattern gas detectors (MPGDs) offer order-of-magnitude improvement in sensitivity over more traditional techniques based on X-ray scattering. This new technique places some of the most interesting astronomical observations within reach of even a small, dedicated mission. The most sensitive instrument would be a photoelectric polarimeter at the focus of 2 a very large mirror, such as the planned XEUS. Our efforts are focused on a smaller pathfinder mission, which would achieve its greatest sensitivity with large-area, low-background, collimated polarimeters. We have recently demonstrated a MPGD polarimeter using amorphous silicon thin-film transistor (TFT) readout suitable for the focal plane of an X-ray telescope. All the technologies used in the demonstration polarimeter are scalable to the areas required for a high-sensitivity collimated polarimeter. Leywords: X-ray polarimetry, particle tracking, proportional counter, GEM, pixel readout

Black, J. K.; Deines-Jones, P.; Jahoda, K.; Ready, S. E.; Street, R. A.

2003-01-01

281

High open circuit voltages of solar cells based on quantum dot and dye hybrid-sensitization  

NASA Astrophysics Data System (ADS)

A type of solar cell based on quantum dot (QD) and dye hybrid-sensitized mesoporous TiO2 film electrode was designed and reported. The electrode was consisted of a TiO2 nanoparticle (NP) thin film layer sensitized with CdS quantum dot (QD) and an amorphous TiO2 coated TiO2 NP thin film layer that sensitized with C106 dye. The amorphous TiO2 layer was obtained by TiCl4 post-treatment to improve the properties of solar cells. Research showed that the solar cells fabricated with as-prepared hybrid-sensitized electrode exhibited excellent photovoltaic performances and a fairly high open circuit voltage of 796 mV was achieved.

Zhao, Yujie; Bala, Hari; Zhao, Wanyu; Chen, Jingkuo; Li, Huayang; Fu, Wuyou; Sun, Guang; Cao, Jianliang; Zhang, Zhanying

2014-01-01

282

CO sensitive nanocrystalline LaCoO 3 perovskite sensor prepared by high energy ball milling  

Microsoft Academic Search

This paper reports high energy ball milling as a promising nanostructured perovskite synthesis route to develop high sensitive and low cost nano-perovskite gas sensors. CO gas sensing properties of thick film LaCoO3 perovskite prepared by (a) high energy ball milling, (b) solgel and (c) solid state reaction have been comparatively studied under 100ppm CO in dry air at different operating

Mohammad Ghasdi; Houshang Alamdari

2010-01-01

283

A hybrid LPG/CFBG for highly sensitive refractive index measurements.  

PubMed

A simple and high sensitive method employing a hybrid long period grating (LPG)/chirped fiber Bragg grating (CFBG) for refractive index (RI) measurements is proposed and investigated experimentally. The wide wavelength range of backward cladding modes are excited through the coupling and recoupling between LPG and CFBG. Experimental results indicate that the recoupled cladding modes between LPG and CFBG and core mode are modulated by the surrounding RI and highly sensitive RI measurements can be achieved by simply measuring the reflected intensity changes of the recoupled cladding modes and core mode. PMID:22969347

Sun, An; Wu, Zhishen

2012-01-01

284

Chemically attached gold nanoparticle-carbon nanotube hybrids for highly sensitive SERS substrate  

NASA Astrophysics Data System (ADS)

Surface-enhanced Raman spectroscopy (SERS) has been shown as one of the most powerful analytical tool with high sensitivity. In this manuscript, we report the chemical design of SERS substrate, based on gold nanoparticles of different shapes-decorated with carbon nanotube with an enhancement factor of 7.5 10 10. Shape dependent result shows that popcorn shape gold nanoparticle decorated SWCNT is the best choice for SERS substrate due to the existence of 'lightning rod effect' through several sharp edges or corners. Our results provide a good approach to develop highly sensitive SERS substrates and can help to improve the fundamental understanding of SERS phenomena.

Beqa, Lule; Singh, Anant Kumar; Fan, Zheng; Senapati, Dulal; Ray, Paresh Chandra

2011-08-01

285

Highly sensitive twist sensor based on tilted fiber Bragg grating of polarization-dependent properties  

NASA Astrophysics Data System (ADS)

The transmission intensity of the tilted fiber Bragg grating (TFBG) is strongly dependent on the polarization properties of the TFBG. The polarization characteristic of the cladding modes can be used for twist measuring. In this paper, a highly sensitive fiber twist sensor is proposed. The transmission intensity on the strong loss wavelength showed a quasi-sin ? changing with the twist angle ranging from 0 to 180 for S- or P-polarized input. A high sensitivity of 0.299 dB/ is achieved, which is almost 17.9 times higher than that of the current similar existing twist sensor. The twist angle can be measured precisely with the matrix.

Lu, Yanfang; Shen, Changyu; Chen, Debao; Chu, Jinlei; Wang, Qiang; Dong, Xinyong

2014-10-01

286

A sensitive, simple and robust LC-MS/MS method for the simultaneous quantification of seven androgen- and estrogen-related steroids in postmenopausal serum.  

PubMed

Steroids were first analyzed by immunoassay-based methods followed by gas chromatography mass spectrometry (GC-MS or GC-MS/MS) with derivatization techniques since steroids are neutral and do not ionize at a high level using the electrospray ionization technique. We now report a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantification of seven steroidal compounds, i.e., estradiol (E2), estrone (E1), testosterone (Testo), dihydrotestosterone (DHT), androst-5-ene-3?, 17?-diol (5-diol), dehydroepiandrosterone (DHEA) and androstenedione (4-dione). The system used is a UPLC-MS/MS (Qtrap 6500) system. With this method, the sample preparation is the combination of liquid-liquid extraction and a simple selective derivatization for only E1 and E2. This assay method is simple and practically eliminates potential contamination. Low quantification limits of 1pg/mL, 4pg/mL, 50pg/mL, 10pg/mL, 100pg/mL, 500pg/mL and 100pg/mL have been found, respectively for the steroids mentioned above. Without derivatization, DHT sensitivity can be as low as 4pg/mL with S/N?5. A full validation has been performed for the seven compounds in compliance with GLP and FDA guidelines for bioanalytical method development and validation. Recovery of all seven compounds in unstripped serum is similar to that in stripped serum: 72.1-84.7% for E2, 83.6-94.5% for E1, 88.2-90.3% for Testo, 82.0-90.6% for DHT, 84.9-92.0% for 5-diol, 88.1-93.8% for DHEA and 86.2-90.3% for 4-dione, respectively. A good linearity is obtained with R>0.99 for each compound within its calibration range. Accuracies of all levels of QC are within the range of 15% for all seven compounds. The between day variation coefficients are 6.1-8.9% for the low limits of quantification of all seven compounds with 0.7-6.1% for higher levels of QCs for all seven compounds. All results of other test parameters similarly meet the acceptance criteria of EndoCeutics SOPs and FDA guidelines. By comparison of GC-MS/MS and LC-MS/MS data for six derivatized and nonderivatized free steroids, the present data show the crucial importance to use validated assays according to the FDA guidelines to increase specificity, precision and reliability of the absolute values associated with MS/MS-based assays. This method has already been applied to series of samples from clinical trials and is ready for wide clinical use. PMID:25158021

Ke, Yuyong; Bertin, Jonathan; Gonthier, Renaud; Simard, Jean-Nicolas; Labrie, Fernand

2014-10-01

287

High-resolution, high sensitivity detectors for molecular imaging with radionuclides: The coded aperture option  

NASA Astrophysics Data System (ADS)

Molecular imaging with radionuclides is a very sensitive technique because it allows to obtain images with nanomolar or picomolar concentrations. This has generated a rapid growth of interest in radionuclide imaging of small animals. Indeed radiolabeling of small molecules, antibodies, peptides and probes for gene expression enables molecular imaging in vivo, but only if a suitable imaging system is used. Detecting small tumors in humans is another important application of such techniques. In single gamma imaging, there is always a well known tradeoff between spatial resolution and sensitivity due to unavoidable collimation requirements. Limitation of the sensitivity due to collimation is well known and affects the performance of imaging systems, especially if only radiopharmaceuticals with limited uptake are available. In many cases coded aperture collimation can provide a solution, if the near field artifact effect can be eliminated or limited. At least this is the case for "small volumes" imaging, involving small animals. In this paper 3D-laminography simulations and preliminary measurements with coded aperture collimation are presented. Different masks have been designed for different applications showing the advantages of the technique in terms of sensitivity and spatial resolution. The limitations of the technique are also discussed.

Cusanno, F.; Cisbani, E.; Colilli, S.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lo Meo, S.; Lucentini, M.; Magliozzi, M. L.; Santavenere, F.; Lanza, R. C.; Majewski, S.; Cinti, M. N.; Pani, R.; Pellegrini, R.; Orsini Cancelli, V.; De Notaristefani, F.; Bollini, D.; Navarria, F.; Moschini, G.

2006-12-01

288

High-sensitivity compact ultrasonic detector based on a pi-phase-shifted fiber Bragg grating.  

PubMed

A highly sensitive compact hydrophone, based on a pi-phase-shifted fiber Bragg grating, has been developed for the measurement of wideband ultrasonic fields. The grating exhibits a sharp resonance, whose centroid wavelength is pressure sensitive. The resonance is monitored by a continuous-wave (CW) laser to measure ultrasound-induced pressure variations within the grating. In contrast to standard fiber sensors, the high finesse of the resonance--which is the reason for the sensor's high sensitivity--is not associated with a long propagation length. Light localization around the phase shift reduces the effective size of the sensor below that of the grating and is scaled inversely with the resonance spectral width. In our system, an effective sensor length of 270 ?m, pressure sensitivity of 440 Pa, and effective bandwidth of 10 MHz were achieved. This performance makes our design attractive for medical imaging applications, such as optoacoustic tomography, in which compact, sensitive, and wideband acoustic detectors are required. PMID:21593906

Rosenthal, Amir; Razansky, Daniel; Ntziachristos, Vasilis

2011-05-15

289

In situ, high sensitivity, measurement of 90strontium in ground water using Cherenkov light  

NASA Astrophysics Data System (ADS)

The measurement of 90Sr in soils and ground water is important for characterization and remediation of radioactively contaminated sites. Measuring the 90Sr content to a few pCi/g of soil has been accomplished based on a design of scintillating fibers in a multilayered configuration measuring the high-energy beta emitted from 90Y decay (when in secular equilibrium with 90Sr), but has not been applied to water because the technique is sensitive to only the first few mm of soil. The volume of the source to which the detector is sensitive limits the theoretical sensitivity of such a detector, unless chemical preprocessing to strip the 90Sr from the water is performed. 90Sr activity in water can be quantified by detecting the high-energy beta particle by the Cherenkov light it produces when the high-energy beta from 90Y passes through the medium. We have used this phenomenon to sensitively measure 90Sr ( 90Y) from a volume of water large enough (765 cm 3) to make very sensitive measurements with short count times. For counting intervals of about 1000 s, we were able to achieve a minimum detectable concentration (MDC) (at 4.65 ? above background) of 14 pCi/L, and for 3000 s counts the MDC dropped to the drinking water limit of 8 pCi/L.

Bowyer, T. W.; Geelhood, B. D.; Hossbach, T. W.; Hansen, R.; Wilcox, W. A.

2000-03-01

290

Polymer Microring Resonators for High-Sensitivity and Wideband Photoacoustic Imaging  

PubMed Central

Polymer microring resonators have been exploited for high-sensitivity and wideband photoacoustic imaging. To demonstrate high-sensitivity ultrasound detection, high-frequency photoacoustic imaging of a 49-?m-diameter black bead at an imaging depth of 5 mm was imaged photoacoustically using a synthetic 2-D array with 249 elements and a low laser fluence of 0.35 mJ/cm2. A bandpass filter with a center frequency of 28 MHz and a bandwidth of 16 MHz was applied to all element data but without signal averaging, and a signal-to-noise ratio of 16.4 dB was obtained. A wideband detector response is essential for imaging reconstruction of multiscale objects, e.g., various sizes of tissues, by using a range of characteristic acoustic wavelengths. A simulation of photoacoustic tomography of beads shows that objects with their boundaries characteristic of high spatial frequencies and the inner structure primarily of low spatial frequency components can be faithfully reconstructed using such a detector. Photoacoustic tomography experiments of 49- and 301-?m-diameter beads were presented. A high resolution of 12.5 ?m was obtained. The boundary of a 301-?m bead was imaged clearly. The results demonstrated that the high sensitivity and broadband response of polymer microring resonators have potential for high resolution and high-fidelity photoacoustic imaging. PMID:19942534

Chen, Sung-Liang; Huang, Sheng-Wen; Ling, Tao; Ashkenazi, Shai; Guo, L. Jay

2010-01-01

291

Food intake and energy expenditure are increased in high-fat-sensitive but not in high-carbohydrate-sensitive obesity-prone rats.  

PubMed

Obesity-prone (OP) rodents are used as models of human obesity predisposition. The goal of the present study was to identify preexisting defects in energy expenditure components in OP rats. Two studies were performed. In the first one, male Wistar rats (n = 48) were fed a high-carbohydrate diet (HCD) for 3 wk and then a high-fat diet (HFD) for the next 3 wk. This study showed that adiposity gain under HCD was 2.9-fold larger in carbohydrate-sensitive (CS) than in carbohydrate-resistant (CR) rats, confirming the concept of "carbohydrate-sensitive" rats. Energy expenditure (EE), respiratory quotient (RQ), caloric intake (CI), and locomotor activity measured during HFD identified no differences in EE and RQ between fat-resistant (FR) and fat-sensitive (FS) rats, and indicated that obesity developed in FS rats only as the result of a larger CI not fully compensated by a parallel increase in EE. A specific pattern of spontaneous activity, characterized by reduced activity burst intensity, was identified in FS rats but not in CS ones. This mirrors a previous observation that under HCD, CS but not FS rats, exhibited bursts of activity of reduced intensity. In a second study, rats were fed a HFD for 3 wk, and the components of energy expenditure were examined by indirect calorimetry in 10 FR and 10 FS rats. This study confirmed that a low basal EE, reduced thermic effect of feeding, defective postprandial energy partitioning, or a defective substrate utilization by the working muscle are not involved in the FS phenotype. PMID:24898839

Azzout-Marniche, Dalila; Chaumontet, Catherine; Nadkarni, Nachiket A; Piedcoq, Julien; Fromentin, Gilles; Tom, Daniel; Even, Patrick C

2014-08-01

292

A low-power, high-sensitivity micromachined optical magnetometer R. Mhaskar,1,2  

E-print Network

A low-power, high-sensitivity micromachined optical magnetometer R. Mhaskar,1,2 S. Knappe,1,2 and J magnetometer based on a microfabricated 87 Rb vapor cell in a micromachined silicon sensor head. The alkali-optically coupled beam optically pumps and interrogates the atoms. The magnetometer operates on 140 mW of heating

Bentz, Dale P.

293

Highly sensitive fiber Bragg grating refractive index sensors Wei Liang, Yanyi Huang,a  

E-print Network

Highly sensitive fiber Bragg grating refractive index sensors Wei Liang, Yanyi Huang,a Yong Xu We combine fiber Bragg grating FBG technology with a wet chemical etch-erosion procedure American Institute of Physics. DOI: 10.1063/1.1904716 Since the early 1990s, fiber Bragg grating FBG

Huang, Yanyi

294

Simple autocollimation laser refractometer with highly sensitive, fiber-optic output.  

PubMed

A simple autocollimation scheme for a laser refractometer with a highly sensitive, single-mode, fiber-optic output is described. It allows for the determination of the refractive index and dispersion of optical materials with an accuracy exceeding 10(-5), which is confirmed by both experimental and analytical investigations. PMID:21037717

Ilev, I K

1995-04-01

295

High-sensitivity rotation sensing with atom interferometers using Aharonov-Bohm effect  

Microsoft Academic Search

In recent years there has been significant activity in research and development of high sensitivity accelerometers and gyroscopes using atom interferometers. In these devices, a fringe shift in the interference of atom de Broglie waves indicates the rotation rate of the interferometer relative to an inertial frame of reference. In both optical and atomic conventional Sagnac interferometers, the resultant phase

2006-01-01

296

A New Kind of Laser Microphone Using High Sensitivity Pulsed Laser Vibrometer  

NASA Technical Reports Server (NTRS)

We demonstrate experimentally a new kind of laser microphone using a highly sensitive pulsed laser vibrometer. By using the photo-electromotive-force (photo-EMF) sensors, we present data indicating the real-time detection of surface displacements as small as 4 pm.

Wang, Chen-Chia; Trivedi, Sudhir; Jin, Feng; Swaminathan, V.; Prasad, Narasimha S.

2008-01-01

297

Matrix-addressable infrared filters for the protection of highly sensitive detectors  

Microsoft Academic Search

Highly sensitive infrared detectors have to be protected against the impact of intense infrared radiation, for example from lasers or sun light. Conventional laser safety filters work only in a limited wavelength range, electro-optical shutters reduce the transmission significantly and micro-opto- mechanical systems (MOEMS) show problems with picture quality due to difficulties in aligning precisely all mirrors. As in many

H. Obloh; W. Muller-Sebert; D. Brink; W. Fehrenbach; Chr. Nebel; Chr. Wild; E. Worner

2011-01-01

298

Rats bred for high alcohol drinking are more sensitive to delayed and probabilistic outcomes.  

PubMed

Alcoholics and heavy drinkers score higher on measures of impulsivity than nonalcoholics and light drinkers. This may be because of factors that predate drug exposure (e.g. genetics). This study examined the role of genetics by comparing impulsivity measures in ethanol-naive rats selectively bred based on their high [high alcohol drinking (HAD)] or low [low alcohol drinking (LAD)] consumption of ethanol. Replicates 1 and 2 of the HAD and LAD rats, developed by the University of Indiana Alcohol Research Center, completed two different discounting tasks. Delay discounting examines sensitivity to rewards that are delayed in time and is commonly used to assess 'choice' impulsivity. Probability discounting examines sensitivity to the uncertain delivery of rewards and has been used to assess risk taking and risk assessment. High alcohol drinking rats discounted delayed and probabilistic rewards more steeply than LAD rats. Discount rates associated with probabilistic and delayed rewards were weakly correlated, while bias was strongly correlated with discount rate in both delay and probability discounting. The results suggest that selective breeding for high alcohol consumption selects for animals that are more sensitive to delayed and probabilistic outcomes. Sensitivity to delayed or probabilistic outcomes may be predictive of future drinking in genetically predisposed individuals. PMID:18518928

Wilhelm, C J; Mitchell, S H

2008-10-01

299

A high sensitivity of children to swimming associated gastrointestinal illness (response to letter by Linn)  

EPA Science Inventory

We disagree with Mr. Linn?s interpretation of our paper, ?High Sensitivity of Children to Swimming-Associated Gastrointestinal Illness?.1 His comments are focused on hypothetical interpretation of our results as related to criteria development rather than the science presented. ...

300

Silicon Photonic Crystal Microcavity Biosensors for Label Free Highly Sensitive and Specific Lung Cancer Detection  

E-print Network

detect lung cancer cell lysates with high sensitivity down to 2 cells per microliter with silicon based detection of control experiment to verify specificity again. Primary lung cancer develops from epithelial a prominent role in controlling the EMT process in lung cancer [7]. In this paper, we present proof

Chen, Ray

301

Ultra-high sensitivity photodetector arrays with integrated amplification and passivation nano-layers  

NASA Astrophysics Data System (ADS)

Miniaturized field-deployable spectrometers used for rapid analysis of chemical and biological substances require high-sensitivity photo detectors. For example, in a Raman spectroscopy system, the receiver must be capable of high-gain, low-noise detection performance due to the intrinsically weak signals produced by the Raman effects of most substances. We are developing a novel, high-gain hetero-junction phototransistor (HPT) detector which employs two nano-structures simultaneously: a 3-30 nm passivation layer that enables micron-sized devices, large-scale integration and low-cost products; and a 50-65 nm amplification layer that offers high sensitivity with 1,000x amplification and zero avalanche access noise. We report preliminary tests on single pixels, validating the design target of >1,000 Ampere/Watt responsivity at the near infrared wavelength of 1550nm, which is 100 times more sensitive than InGaAs avalanche photodiodes, the most sensitive commercially available photo-detector in this wavelength range, under their normal operation conditions. Integrated into a detector array, this technology has application for Laser-Induced Breakdown Spectroscopy (LIBS), pollution monitoring, pharmaceutical manufacturing by reaction monitoring, chemical & biological transportation safety, and bio-chemical analysis in planetary exploration.

Yao, Jie; Wang, Sean; Zhou, Jack; Li, Ken; Lange, Michael; Yang, Weiguo; Gardner, Patrick; Peltz, Leora; Frampton, Robert; Hunt, Jeffrey H.; Becker, Jill

2009-02-01

302

On noise- and period-time sensitivity in high order repetitive control  

Microsoft Academic Search

Repetitive control is useful if periodic disturbances act on a control system. Perfect (asymptotic) disturbance rejection is achieved if the period-time is exactly known. The improved disturbance rejection at the periodic frequency and its harmonics is achieved at the expense of a degraded system sensitivity at intermediate frequencies. A convex optimization problem is defined for the design of high-order repetitive

Maarten Steinbuch; Siep Weiland; Johan Van den Eerenbeemt; Tarunraj Singh

2004-01-01

303

A highly sensitive method for measurement of lipid hydroperoxides by iodimetry and amperometric endpoint  

Microsoft Academic Search

SUMMARY A simple, accurate, and highly sensitive method is described for measurement of lipid hydroperoxides, utilizing standard iodimetric reactions and an amperometric endpoint. Measurement of 10-8 equivalents of hydroperoxides is feasible in samples of milligram size. Several parameters of the analysis have been defined. This report describes a procedure that permits accurate and specific measurement of lipid peroxides by iodimetry

KURT OETTE; M. L. PETERSON; R. L. MCAULEY

304

Incorporation of beams into bossed diaphragm for a high sensitivity and overload micro pressure sensor  

NASA Astrophysics Data System (ADS)

The paper presents a piezoresistive absolute micro pressure sensor, which is of great benefits for altitude location. In this investigation, the design, fabrication, and test of the sensor are involved. By analyzing the stress distribution of sensitive elements using finite element method, a novel structure through the introduction of sensitive beams into traditional bossed diaphragm is built up. The proposed configuration presents its advantages 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 equations about the sensor. Nonlinear optimization by MATLAB is carried out to determine the structure dimensions. The output signals in both static and dynamic environments are evaluated. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the fabrication process is discussed. Experimental results demonstrate the sensor features a high sensitivity of 11.098 ?V/V/Pa in the operating range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure to promise its survival under atmosphere. Due to the excellent performance above, the sensor can be applied in measuring the absolute micro pressure lower than 500 Pa.

Yu, Zhongliang; Zhao, Yulong; Sun, Lu; Tian, Bian; Jiang, Zhuangde

2013-01-01

305

Incorporation of beams into bossed diaphragm for a high sensitivity and overload micro pressure sensor.  

PubMed

The paper presents a piezoresistive absolute micro pressure sensor, which is of great benefits for altitude location. In this investigation, the design, fabrication, and test of the sensor are involved. By analyzing the stress distribution of sensitive elements using finite element method, a novel structure through the introduction of sensitive beams into traditional bossed diaphragm is built up. The proposed configuration presents its advantages 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 equations about the sensor. Nonlinear optimization by MATLAB is carried out to determine the structure dimensions. The output signals in both static and dynamic environments are evaluated. Silicon bulk micromachining technology is utilized to fabricate the sensor prototype, and the fabrication process is discussed. Experimental results demonstrate the sensor features a high sensitivity of 11.098 ?V/V/Pa in the operating range of 500 Pa at room temperature, and a high overload resistance of 200 times overpressure to promise its survival under atmosphere. Due to the excellent performance above, the sensor can be applied in measuring the absolute micro pressure lower than 500 Pa. PMID:23387684

Yu, Zhongliang; Zhao, Yulong; Sun, Lu; Tian, Bian; Jiang, Zhuangde

2013-01-01

306

High-Sensitivity Analysis of Human Plasma Proteome by Immobilized Isoelectric Focusing Fractionation Coupled to Mass  

E-print Network

High-Sensitivity Analysis of Human Plasma Proteome by Immobilized Isoelectric Focusing-Jun Deng, Qi-Chang Xia, and Rong Zeng* Research Center for Proteome Analysis, Key Lab of Proteomics · proteomics · linear ion trap mass spectrometry Introduction The prefractionation techniques in proteome

Tian, Weidong

307

Sensitivity of single crystals to the circular polarization of high-energy gamma-quanta  

E-print Network

It is shown that single crystals are sensitive to the initial circular polarization of gamma-quanta with energies in tens GeV and more. The possibility of measurement of gamma-beam polarization is discussed. The obtained results may be useful for creation of polarimeters for high energy beams of gamma-quanta.

V. A. Maisheev

1999-12-21

308

Highly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy  

E-print Network

explosives3 so detection of trace amounts of explosive, for example in security screening, also requiresHighly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy Manish Dubey, Steven and direct detection of NO at these levels is important. NO is also a decomposition product of several

Schwartz, Jeffrey

309

15Data Corruption by High-Energy Particles Solar flares can severely affect sensitive instruments in  

E-print Network

15Data Corruption by High-Energy Particles Solar flares can severely affect sensitive instruments the approximate times of the events. Problem 1: At about what time did the solar flare first erupt on the sun://spacemath.gsfc.nasa.gov #12;15 Answer Key: Problem 1: At about what time did the solar flare first erupt on the sun? Answer

310

Lighting up fluoride ions in cellular mitochondria using a highly selective and sensitive fluorescent probe.  

PubMed

We report a highly selective and sensitive fluorescent probe () for detecting fluoride ions, for the first time, lighting up the fluoride ions in mitochondria with a strong green fluorescence. could be easily prepared as fluoride paper test strips to detect fluoride ions in aqueous solutions with a detection limit as low as 19 ppb. PMID:25268252

Zhang, Shiling; Fan, Jiangli; Zhang, Shuangzhe; Wang, Jingyun; Wang, Xianwu; Du, Jianjun; Peng, Xiaojun

2014-10-16

311

High sensitivity mapping of Ti distributions in Hadean zircons T. Mark Harrison , Axel K. Schmitt  

E-print Network

High sensitivity mapping of Ti distributions in Hadean zircons T. Mark Harrison , Axel K. Schmitt there exists no known rock record. Ti concentrations of Hadean zircons indicate a spectrum of crystallization peak has been interpreted to indicate the existence of `wet' melting conditions during the Hadean

312

A high sensitivity satellite-borne television camera for the detection of auroras.  

PubMed

A high sensitivity satellite-borne television camera has been developed to measure such faint light sources as auroras. A secondary electron conduction (SEC) television camera tube is used as the image sensor. In the present application for the Rice/NASA satellites code-named Owls, the tube is exposed by the application of a high voltage pulse of 0.1 sec or 0.2 sec duration. The picture is scanned for about 19 sec, and the video is digitized in synchronism with the satellite PCM system. The television data are then telemetered to the ground either real time or stored in one of the tape recorders. The optical system super-imposes star images on the picture for azimuthal aspect reference. The sensitivity of the slow scan camera was measured; it agrees with the sensitivity of a camera scanning at normal scan rate. Comparison was made of the relative sensitivity of the camera at the wavelength of the three most important auroral components. The camera has sensitivity comparable with the dark-adapted human eye. The weight of the system is 3.9 kg, and the power dissipation is 3.9 W. PMID:20068849

Mende, S B; O'Brien, B J

1968-08-01

313

Highly stretchable and sensitive strain sensor based on silver nanowire-elastomer nanocomposite.  

PubMed

The demand for flexible and wearable electronic devices is increasing due to their facile interaction with human body. Flexible, stretchable and wearable sensors can be easily mounted on clothing or directly attached onto the body. Especially, highly stretchable and sensitive strain sensors are needed for the human motion detection. Here, we report highly flexible, stretchable and sensitive strain sensors based on the nanocomposite of silver nanowire (AgNW) network and PDMS elastomer in the form of the sandwich structure (i.e., AgNW thin film embedded between two layers of PDMS). The AgNW network-elastomer nanocomposite based strain sensors show strong piezoresistivity with tunable gauge factors in the ranges of 2 to 14 and a high stretchability up to 70%. We demonstrate the applicability of our high performance strain sensors by fabricating a glove integrated with five strain sensors for the motion detection of fingers and control of an avatar in the virtual environment. PMID:24749972

Amjadi, Morteza; Pichitpajongkit, Aekachan; Lee, Sangjun; Ryu, Seunghwa; Park, Inkyu

2014-05-27

314

High sensitive formaldehyde graphene gas sensor modified by atomic layer deposition zinc oxide films  

NASA Astrophysics Data System (ADS)

Zinc oxide (ZnO) thin films with various thicknesses were fabricated by Atomic Layer Deposition on Chemical Vapor Deposition grown graphene films and their response to formaldehyde has been investigated. It was found that 0.5 nm ZnO films modified graphene sensors showed high response to formaldehyde with the resistance change up to 52% at the concentration of 9 parts-per-million (ppm) at room temperature. Meanwhile, the detection limit could reach 180 parts-per-billion (ppb) and fast response of 36 s was also obtained. The high sensitivity could be attributed to the combining effect from the highly reactive, top mounted ZnO thin films, and high conductive graphene base network. The dependence of ZnO films surface morphology and its sensitivity on the ZnO films thickness was also investigated.

Mu, Haichuan; Zhang, Zhiqiang; Zhao, Xiaojing; Liu, Feng; Wang, Keke; Xie, Haifen

2014-07-01

315

White-light interferometry using pseudo random-modulation for high-sensitivity and high-selectivity measurements  

Microsoft Academic Search

We developed a white-light interferometer that uses pseudo random-modulation for high-sensitivity, high-selectivity measurements of the surface profile of three-dimensional objects. The pseudo random-modulation is achieved by using a multi-segment mirror, where each segment has a different height in a maximum shift-register sequence (M-sequence). Preliminary experiments, where the white-light source was a halogen lamp and the test object was a plane

Akiko Hirai; Katuo Seta; Hirokazu Matsumoto

1999-01-01

316

Performance evaluation of high sensitive DRE camera for cultural heritage in subdued light conditions  

Microsoft Academic Search

We proposed a color video generation method for spatio-temporal high resolution video imaging in dark conditions. The method (dual resolutions and exposures(DRE) method) consists of a high sensitive imaging with employing long time exposure and a subsequent spatio-temporal decomposition process which suppresses a motion blur caused by the long time exposure. Imaging step captures RGB color video sequences with different

Sanzo Ugawa; Takeo Azuma; Taro Imagawa; Yusuke Okada

2010-01-01

317

Advanced nanoscale separations and mass spectrometry for sensitive high-throughput proteomics  

Microsoft Academic Search

We review recent development in separations and mass spectrometric instrumentation for sensitive and high-throughput proteomic analyses. These efforts have been primarily focused on the development of high-efficiency (separation peak capacity of ~103) nanoscale liquid chromatography (nanoLC; e.g., flow rates extending down to ~20 nL\\/min at optimal separation linear velocities through narrow packed capillaries) in combination with advanced mass spectrometry (MS),

Yufeng Shen; Richard D. Smith

2005-01-01

318

Diagnosis of Canine Leptospirosis by a Highly Sensitive FRET-PCR Targeting the lig Genes  

PubMed Central

Canine leptospirosis is underdiagnosed due to its wide spectrum of clinical presentations and the lack of a rapid and sensitive test for the accurate diagnosis of acute and chronic infections. In this study, we developed a highly sensitive and specific fluorescence resonance energy transfer (FRET)-PCR to detect common pathogenic leptospires in dogs, including Leptospira interrogans serovars Autumnalis, Canicola, Copenhageni (Icterohaemorrhagiae serogroup) and Pomona, and Leptospira kirschneri serovar Grippotyphosa. This PCR targets the lig genes, exclusively found in the pathogenic Leptospira species but not in saprophytic species (L. biflexa). A robust, high-stringency step-down real-time platform was coupled to the highly specific detection of leptospiral DNA by fluorescently labeled FRET probes. This enabled the detection of a single copy of the lig gene in a PCR containing DNA from up to 50 L canine blood or 400 L urine. Sensitivity determination by use of limiting serial dilutions of extracted leptospiral DNA indicated that the lig FRET-PCR we established was almost 100-fold more sensitive than the widely accepted lipL32 SYBR assay and 10-fold more sensitive than a 16S rRNA TaqMan assay. Application of this method to 207 dogs with potential leptospiral infection enabled us to diagnose three cases of canine leptospirosis characterized by low amounts of leptospiral DNA in body fluids. Detection of canine leptospirosis with the lig FRET-PCR was more sensitive with the lig FRET-PCR than with the 16S rRNA TaqMan PCR, which detected only 2 of the 3 cases, and the lipL32 SYBR PCR, which detected none of the 3 dogs with leptospirosis. PMID:24586833

Ahluwalia, Sudhir K.; Gao, Dongya; Verma, Ashutosh; Wang, Chengming; Kaltenboeck, Bernhard

2014-01-01

319

Nature's crucible: Manufacturing optical nonlinearities for high resolution, high sensitivity encoding in the compound eye of the fly, Musca domestica  

NASA Technical Reports Server (NTRS)

The number of pixels per unit area sampling an image determines Nyquist resolution. Therefore, the highest pixel density is the goal. Unfortunately, as reduction in pixel size approaches the wavelength of light, sensitivity is lost and noise increases. Animals face the same problems and have achieved novel solutions. Emulating these solutions offers potentially unlimited sensitivity with detector size approaching the diffraction limit. Once an image is 'captured', cellular preprocessing of information allows extraction of high resolution information from the scene. Computer simulation of this system promises hyperacuity for machine vision.

Wilcox, Mike

1993-01-01

320

ZnO-NiO hetero-nanostructures as highly sensitive and selective triethylamine sensor  

NASA Astrophysics Data System (ADS)

Al-doped ZnO nanorods arrays on NiO nanofibers to construct a typical ZnO-NiO hetero-nanostructure on Al2O3 substrate have been obtained by electrospinning and hydrothermal methods. The sensors based on this hetero-nanostructures exhibit high selectivity and sensitivity towards triethylamine gas under operating temperature of 250 C, and Al doping has a great influence on the air-sensitive performance of the sensors. Our results indicate that the ZnO-NiO hetero-nanostructure is a potential candidate for gas sensors with good performances for practical applications.

Guo, Ting; Luo, Yidong; Zhang, Yujun; Lin, Yuan-Hua; Nan, Ce-Wen

2014-07-01

321

A small mission featuring an imaging x-ray polarimeter with high sensitivity  

NASA Astrophysics Data System (ADS)

We show that meaningful, highly sensitive x-ray polarimetry with imaging capability is possible with a small mission tailored to the NASA Explorer program. Such a missionderived from the Imaging X-ray Polarimetry Explorer (IXPE) proposed to a previous NASA calltakes advantage of progress in light-weight x-ray optics and in gas pixel detectors to achieve sensitive time-resolved, spectrometric, imaging polarimetry. We outline the main characteristics and requirements of this mission and provide a realistic assessment of its scientific utility for modeling point-like and extended x-ray sources and for studying physical processes (including questions of fundamental physics).

Weisskopf, Martin C.; Baldini, Luca; Bellazini, Ronaldo; Brez, Alessandro; Costa, Enrico; Dissly, Richard; Elsner, Ronald F.; Fabiani, Sergio; Matt, Giorgio; Minuti, Massimo; Muleri, Fabio; O'Dell, Steve; Pinchera, Michele; Ramsey, Brian; Rubini, Alda; Sgro', Carmelo; Soffitta, Paolo; Spandre, Gloria

2013-09-01

322

A high sensitive fiber Bragg grating(FBG) geophone detecting system  

NASA Astrophysics Data System (ADS)

A high sensitive fiber Bragg grating (FBG) geophone detecting system based on narrow line width distributed feedback (DFB) laser is realized by using filtering demodulation. Sensitivity of FBG geophone lies on the structure of the sensor shell and the shape of the reflectivity spectrum of FBG. Experiments on the detecting system's frequency character have been done. Results show that this geophone can detect the smallest acceleration of 1mm/s2 with a flat response from 5Hz to 40Hz.. The experiments on coal mine exhibit that the geophone can be used to measure microseismic signals. The detecting system shows great prospect in micro-seismic detection, and geological disasters detecting.

Wang, Jin-Yu; Qi, Hai-Feng; Song, Guang-Dong; Wang, Chang; Liu, Tong-Yu

2012-02-01

323

High sensitivity photoconductivity based measurement setup for the determination of effective recombination lifetime in silicon wafers.  

PubMed

We describe a high sensitivity measurement setup for the determination of recombination parameters in semiconductors at low levels of carrier injection. The setup is based on a lock-in amplifier and on a commercially available contactless conductivity detector. The information on recombination is extracted through the analysis, assuming quasi-steady-state conditions, of the low frequency, sinusoidally modulated photoconductivity signal induced by the illumination of a 950 nm light emitting diode array. Experimental results show a substantial increase in sensitivity with respect to traditional transient or quasi-steady-state techniques based on the same detection principle. The sensitivity bonus can be exploited for the extension of the carrier injection range for which effective recombination lifetime is measurable, both in the case of p-type and n-type wafers. PMID:19485519

Cornagliotti, E; Kang, X; Beaucarne, G; John, J; Poortmans, J; Mertens, R

2009-05-01

324

High-frequency, high-sensitivity acoustic sensor implemented on ALN/Si substrate  

NASA Astrophysics Data System (ADS)

AlN films, 1.6-6.3 ?m thick, were sputtered at 200 C on Si(100) and Si(111) substrates. The films were crack-free, uniform, and c-axis oriented. The experimental phase velocities of surface acoustic waves (SAW) propagating in the AlN/Si structures were estimated and showed only a small discrepancy (20-40 m/s) compared to the calculated theoretical values. A SAW resonator (SAWR)-based chemical sensor, operating at about 700 MHz, was implemented on AlN/Si. The SAWR surface was covered with a polymer film sensitive to relative humidity (RH) changes, already tested for RH sensing in previous works on SAW delay lines implemented on AlN/Si and ZnO/Si and operating at about 130 MHz. The RH mass sensitivity and the detection limit of the SAWR sensor improved by 38% and by one order of magnitude, respectively, compared to the delay line-based sensors previously tested.

Caliendo, C.; Imperatori, P.

2003-08-01

325

Highly sensitive and selective gas sensor using hydrophilic and hydrophobic graphenes.  

PubMed

New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor. PMID:23736838

Some, Surajit; Xu, Yang; Kim, Youngmin; Yoon, Yeoheung; Qin, Hongyi; Kulkarni, Atul; Kim, Taesung; Lee, Hyoyoung

2013-01-01

326

Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes  

PubMed Central

New hydrophilic 2D graphene oxide (GO) nanosheets with various oxygen functional groups were employed to maintain high sensitivity in highly unfavorable environments (extremely high humidity, strong acidic or basic). Novel one-headed polymer optical fiber sensor arrays using hydrophilic GO and hydrophobic reduced graphene oxide (rGO) were carefully designed, leading to the selective sensing of volatile organic gases for the first time. The two physically different surfaces of GO and rGO could provide the sensing ability to distinguish between tetrahydrofuran (THF) and dichloromethane (MC), respectively, which is the most challenging issue in the area of gas sensors. The eco-friendly physical properties of GO allowed for faster sensing and higher sensitivity when compared to previous results for rGO even under extreme environments of over 90% humidity, making it the best choice for an environmentally friendly gas sensor. PMID:23736838

Some, Surajit; Xu, Yang; Kim, Youngmin; Yoon, Yeoheung; Qin, Hongyi; Kulkarni, Atul; Kim, Taesung; Lee, Hyoyoung

2013-01-01

327

R and D of crystal scintillators from enriched isotopes for high sensitivity double ? decay experiments  

SciTech Connect

Experiments to search for neutrinoless double beta decay enters to a new phase when a sensitivity on the level of T{sub 1/2}?10{sup 26}?10{sup 28} yr is required. Scintillating low temperature detectors possess important properties required for high-sensitivity double beta decay experiments: presence of elements of interest, high energy resolution and detection efficiency, low level of background thanks to excellent particle discrimination ability. High concentration of isotope of interest and as low as possible radioactive contamination are important requirements to crystal scintillators. Other crucial issues are maximal output of detectors and minimal loss of enriched materials. Prospects of several scintillation materials, enriched in isotopes promising for double beta decay experiments, are discussed.

Danevich, F. A. [Institute for Nuclear Research, Kyiv (Ukraine)

2013-12-30

328

High-Sensitivity Temperature Sensing Using an Implanted Single Nitrogen-Vacancy Center Array in Diamond  

E-print Network

We presented a high-sensitivity temperature detection using an implanted single Nitrogen-Vacancy center array in diamond. The high-order Thermal Carr-Purcell-Meiboom-Gill (TCPMG) method was performed on the implanted single nitrogen vacancy (NV) center in diamond in a static magnetic field. We demonstrated that under small detunings for the two driving microwave frequencies, the oscillation frequency of the induced fluorescence of the NV center equals approximately to the average of the detunings of the two driving fields. On basis of the conclusion, the zero-field splitting D for the NV center and the corresponding temperature could be determined. The experiment showed that the coherence time for the high-order TCPMG was effectively extended, particularly up to 108 {\\mu}s for TCPMG-8, about 14 times of the value 7.7 {\\mu}s for thermal Ramsey method. This coherence time corresponded to a thermal sensitivity of 10.1 mK/Hz1/2. We also detected the temperature distribution on the surface of a diamond chip in three different circumstances by using the implanted NV center array with the TCPMG-3 method. The experiment implies the feasibility for using implanted NV centers in high-quality diamonds to detect temperatures in biology, chemistry, material science and microelectronic system with high-sensitivity and nanoscale resolution.

Junfeng Wang; Fupan Feng; Jian Zhang; Jihong Chen; Zhongcheng Zheng; Liping Guo; Wenlong Zhang; Xuerui Song; Guoping Guo; Lele Fan; Chongwen Zou; Liren Lou; Wei Zhu; Guanzhong Wang

2014-10-25

329

Application of a sensitivity analysis technique to high-order digital flight control systems  

NASA Technical Reports Server (NTRS)

A sensitivity analysis technique for multiloop flight control systems is studied. This technique uses the scaled singular values of the return difference matrix as a measure of the relative stability of a control system. It then uses the gradients of these singular values with respect to system and controller parameters to judge sensitivity. The sensitivity analysis technique is first reviewed; then it is extended to include digital systems, through the derivation of singular-value gradient equations. Gradients with respect to parameters which do not appear explicitly as control-system matrix elements are also derived, so that high-order systems can be studied. A complete review of the integrated technique is given by way of a simple example: the inverted pendulum problem. The technique is then demonstrated on the X-29 control laws. Results show linear models of real systems can be analyzed by this sensitivity technique, if it is applied with care. A computer program called SVA was written to accomplish the singular-value sensitivity analysis techniques. Thus computational methods and considerations form an integral part of many of the discussions. A user's guide to the program is included. The SVA is a fully public domain program, running on the NASA/Dryden Elxsi computer.

Paduano, James D.; Downing, David R.

1987-01-01

330

Tetrathiatriarylmethyl radical with a single aromatic hydrogen as a highly sensitive and specific superoxide probe  

PubMed Central

Superoxide (O2?) plays crucial roles in normal physiology and disease; however, its measurement remains challenging because of the limited sensitivity and/or specificity of prior detection methods. We demonstrate that a tetrathiatriarylmethyl (TAM) radical with a single aromatic hydrogen (CT02-H) can serve as a highly sensitive and specific O2? probe. CT02-H is an analogue of the fully substituted TAM radical CT-03 (Finland trityl) with an electron paramagnetic resonance (EPR) doublet signal due to its aromatic hydrogen. Owing to the neutral nature and negligible steric hindrance of the hydrogen, O2? preferentially reacts with CT02-H at this site with production of the diamagnetic quinone methide via oxidative dehydrogenation. Upon reaction with O2?, CT02-H loses its EPR signal and this EPR signal decay can be used to quantitatively measure O2?. This is accompanied by a change in color from green to purple, with the quinone methide product exhibiting a unique UVVis absorbance (? =15,900 M?1 cm?1) at 540 nm, providing an additional O2? detection method. More than five-fold higher reactivity of CT02-H for O2? relative to CT-03 was demonstrated, with a second-order rate constant of 1.7 104 M?1 s?1 compared to 3.1 103 M?1 s?1 for CT-03. CT02-H exhibited high specificity for O2? as evidenced by its inertness to other oxidoreductants. The O2? generation rates detected by CT02-H from xanthine/xanthine oxidase were consistent with those measured by cytochrome c reduction but detection sensitivity was 10- to 100-fold higher. EPR detection of CT02-H enabled measurement of very low O2? flux with a detection limit of 0.34 nM/min over 120 min. HPLC in tandem with electrochemical detection was used to quantitatively detect the stable quinone methide product and is a highly sensitive and specific method for measurement of O2?, with a sensitivity limit of ~2 10?13 mol (10 nM with 20-?l injection volume). Based on the O2-dependent linewidth broadening of its EPR spectrum, CT02-H also enables simultaneous measurement of O2 concentration and O2? generation and was shown to provide sensitive detection of extracellular O2? generation in endothelial cells stimulated either by menadione or with anoxia/reoxygenation. Thus, CT02-H is a unique probe that provides very high sensitivity and specificity for measurement of O2? by either EPR or HPLC methods. PMID:23000244

De Pascali, Francesco; Liu, Xiaoping; Villamena, Frederick A.; Zweier, Jay L.

2014-01-01

331

A sensitivity study of the localised surface plasmon resonance of high-definition structured silver nanoparticles in solution  

Microsoft Academic Search

Within this work we present a new class of shaped silver nanoparticle ensembles which have demonstrated high sensitivities to variations in the refractive index of their surrounding environment. The ensembles' collective response has proven to exceed that of other sensitivities quoted in literature by various other nanoparticle structures, with sensitivity values of up to 376.6 nm\\/RIU recorded. A quick, simple

Denise Charles; Patrick Fournet; Stephen Cunningham; Deirdre Ledwith; John M. Kelly; Werner Blau; Margaret Brennan Fournet

2008-01-01

332

absorption sensor for sensitive temperature and species measurements in high-temperature gases  

NASA Astrophysics Data System (ADS)

A continuous-wave laser absorption diagnostic, based on the infrared CO2 bands near 4.2 and 2.7 ?m, was developed for sensitive temperature and concentration measurements in high-temperature gas systems using fixed-wavelength methods. Transitions in the respective R-branches of both the fundamental ? 3 band (~2,350 cm-1) and combination ? 1 + ? 3 band (~3,610 cm-1) were chosen based on absorption line-strength, spectral isolation, and temperature sensitivity. The R(76) line near 2,390.52 cm-1 was selected for sensitive CO2 concentration measurements, and a detection limit of <5 ppm was achieved in shock tube kinetics experiments (~1,300 K). A cross-band, two-line thermometry technique was also established utilizing the R(96) line near 2,395.14 cm-1, paired with the R(28) line near 3,633.08 cm-1. This combination yields high temperature sensitivity (?E" = 3,305 cm-1) and expanded range compared with previous intra-band CO2 sensors. Thermometry performance was validated in a shock tube over a range of temperatures (600-1,800 K) important for combustion. Measured temperature accuracy was demonstrated to be better than 1 % over the entire range of conditions, with a standard error of ~0.5 % and s temporal resolution.

Spearrin, R. M.; Ren, W.; Jeffries, J. B.; Hanson, R. K.

2014-09-01

333

Highly sensitive, patternable organic films at the nanoscale made by bottom-up assembly.  

PubMed

Nanoscale patterning of organic thin films is of great interest for next-generation technologies. To keep pace with the demands of state-of-the-art lithography, both the sensitivity and resolution of the patternable thin films need to be improved. Here we report a highly sensitive polyurea film grown by bottom-up assembly via the molecular layer deposition (MLD) technique, which allows for high-resolution patterning at the nanoscale. The MLD process used in this work provides an exceptionally high degree of control over the film thickness and composition and also offers high coating conformality. The polyurea film was formed by urea coupling reactions between 1,4-diisocyanatobutane and 2,2'-(propane-2,2-diyldioxy)diethanamine precursors and deposited in a layer-by-layer fashion. Acid-labile ketal groups were incorporated into the backbone of the polymer chains to ensure chemically amplified cleaving reactions when combined with photoacid, which was generated by electron-beam activation of triphenylsulfonium triflate soaked into the polyurea film. With electron-beam lithography, sub-100 ?C/cm(2) sensitivity and sub-100 nm resolution were demonstrated using this new bottom-up assembly approach to resist fabrication. PMID:23594160

Zhou, Han; Blackwell, James M; Lee, Han-Bo-Ram; Bent, Stacey F

2013-05-01

334

Highly-sensitive and label-free indium phosphide biosensor for early phytopathogen diagnosis.  

PubMed

The development of highly-sensitive and label-free operating semiconductor-based, biomaterial detecting sensors has important applications in areas such as environmental science, biomedical research and medical diagnostics. In the present study, we developed an Indium Phosphide (InP) semiconductor-based resistive biosensor using the change of its electronic properties upon biomaterial adsorption as sensing element. To detect biomaterial at low concentrations, the procedure of functionalization and covalent biomolecule immobilization was also optimized to guarantee high molecule density and high reproducibility which are prerequisite for reliable results. The characterization, such as biomolecular conjugation efficiency, detection concentration limits, receptor:ligand specificity and concentration detection range was analyzed by using three different biological systems: i) synthetic dsDNA and two phytopathogenic diseases, ii) the severe CB-form of Citrus Tristeza Virus (CTV) and iii) Xylella fastidiosa, both causing great economic loss worldwide. The experimental results show a sensitivity of 1 pM for specific ssDNA detection and about 2 nM for the specific detection of surface proteins of CTV and X. fastidiosa phytopathogens. A brief comparison with other semiconductor based biosensors and other methodological approaches is discussed and confirms the high sensitivity and reproducibility of our InP based biosensor which could be suitable for reliable early infection diagnosis in environmental and life sciences. PMID:22538056

Moreau, Alberto L D; Janissen, Richard; Santos, Clelton A; Peroni, Luis A; Stach-Machado, Dagmar R; de Souza, Alessandra A; de Souza, Anete P; Cotta, Mnica A

2012-01-01

335

High efficiency dye-sensitized solar cells exploiting sponge-like ZnO nanostructures.  

PubMed

Sponge-like nanostructured ZnO layers were successfully employed as photoanodes for the fabrication of highly efficient dye-sensitized solar cells. The sponge-like ZnO layers were obtained by room temperature radio-frequency magnetron sputtering deposition of metallic zinc, followed by thermal oxidation treatment in an ambient atmosphere. The porous films show a 3D branched nanomorphology, with a feature similar to natural coral. The morphological and optical properties of these layers were studied through field emission scanning electron microscopy, specific surface area measurements, ultraviolet-visible transmittance and absorption spectroscopy. The sponge-like ZnO film presents a high density of branches, with a relatively high specific surface area value, and fine optical transmittance. The morphology of the porous structure provides a high number of adsorption sites for the anchoring of sensitizer molecules, making it suitable for the fabrication of ZnO-based photoanodes for dye-sensitized solar cells. The light harvesting performance of the sensitized semiconductor was evaluated by current density vs. voltage measurements, incident photon-to-electron conversion efficiency, open circuit voltage decay and impedance spectroscopy. The modelling of the electrical characteristics evidences a higher electron lifetime and a longer charge diffusion length, if compared to standard TiO(2) nanoparticle based photoanodes. For ZnO films with a thickness up to 18 ?m, a photoconversion efficiency as high as 6.67% and a maximum value of the incident photon-to-electron collection efficiency equal to 87% at 530 nm were demonstrated. PMID:23001064

Sacco, Adriano; Lamberti, Andrea; Gazia, Rossana; Bianco, Stefano; Manfredi, Diego; Shahzad, Nadia; Cappelluti, Federica; Ma, Shuai; Tresso, Elena

2012-12-21

336

Robust emergent climate phenomena associated with the high-sensitivity tail.  

SciTech Connect

Because the potential effects of climate change are more severe than had previously been thought, increasing focus on uncertainty quantification is required for risk assessment needed by policy makers. Current scientific efforts focus almost exclusively on establishing best estimates of future climate change. However, the greatest consequences occur in the extreme tail of the probability density functions for climate sensitivity (the 'high-sensitivity tail'). To this end, we are exploring the impacts of newly postulated, highly uncertain, but high-consequence physical mechanisms to better establish the climate change risk. We define consequence in terms of dramatic change in physical conditions and in the resulting socioeconomic impact (hence, risk) on populations. Although we are developing generally applicable risk assessment methods, we have focused our initial efforts on uncertainty and risk analyses for the Arctic region. Instead of focusing on best estimates, requiring many years of model parameterization development and evaluation, we are focusing on robust emergent phenomena (those that are not necessarily intuitive and are insensitive to assumptions, subgrid-parameterizations, and tunings). For many physical systems, under-resolved models fail to generate such phenomena, which only develop when model resolution is sufficiently high. Our ultimate goal is to discover the patterns of emergent climate precursors (those that cannot be predicted with lower-resolution models) that can be used as a 'sensitivity fingerprint' and make recommendations for a climate early warning system that would use satellites and sensor arrays to look for the various predicted high-sensitivity signatures. Our initial simulations are focused on the Arctic region, where underpredicted phenomena such as rapid loss of sea ice are already emerging, and because of major geopolitical implications associated with increasing Arctic accessibility to natural resources, shipping routes, and strategic locations. We anticipate that regional climate will be strongly influenced by feedbacks associated with a seasonally ice-free Arctic, but with unknown emergent phenomena.

Backus, George A.; Levy, Michael Nathan; Boslough, Mark Bruce Elrick

2010-12-01

337

The Potential Utility of High Resolution Ensemble Sensitivities During Weak Flow in Complex Terrain  

NASA Astrophysics Data System (ADS)

Recent expansion in availability of re-locatable near-surface atmospheric observing sensors introduces the question of where placement maximizes gain in forecast accuracy. Here the potential for ensemble sensitivity analysis (ESA) is examined for high-resolution (?x=4 km) predictions in complex terrain. The primary objective is to determine whether a mesoscale ESA applied at these scales is useful for identifying potential observing locations in weak flow. ESA can be inaccurate when the underlying assumptions of linear dynamics (and Gaussian statistics) are violated, or when the sensitivity cannot be robustly sampled. A case study of a fog event at the Salt Lake City airport (KSLC) provides a useful period for examining these issues, with the additional influence of complex terrain. A realistic upper-air observing network is used in perfect-model ensemble data assimilation experiments, providing the statistics for ESA. Results show that water vapor mixing ratios over KSLC are sensitive to temperature on the first model layer tens of km away, 6 h prior to verification and prior to the onset of fog. Sensitivity 12 h prior is weaker but leads to qualitatively similar results. Temperatures are shown to be a predictor of inversion strength in the Salt Lake basin; the ESA predicts southerly flow and strengthened inversions with warmer temperatures in a few locations. Simple linearity tests show that small perturbations do not lead to the expected forecast change, but larger perturbations do, suggesting that noise can dominate a small perturbation. Assimilating a perfect observation at the maximum sensitivity location produces forecasts more closely agreeing with the ESA. Sampling error evaluation show that similar conclusions can be reached with ensembles as small as 48 members, but smaller ensembles do not produce accurate sensitivity estimates.

Hacker, J.; Wile, S.

2013-12-01

338

A high sensitivity ultralow temperature RF conductance and noise measurement setup.  

PubMed

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milli-Kelvin temperatures. The setup relies on the combination of an interferometric amplification scheme and a quarter-wave impedance transformer, allowing the measurement of noise power spectral densities with gigahertz bandwidth up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwidth make it suitable for applications manipulating single charges at GHz frequencies. PMID:21280842

Parmentier, F D; Mah, A; Denis, A; Berroir, J-M; Glattli, D C; Plaais, B; Fve, G

2011-01-01

339

Highly sensitive detection of chromium (III) ions by resonance Rayleigh scattering enhanced by gold nanoparticles  

NASA Astrophysics Data System (ADS)

Simple and sensitive determination of chromium (III) ions (Cr3+) has potential applications for detecting trace contamination in environment. Here, the assay is based on the enhancement of resonance Rayleigh scattering (RRS) by Cr3+-induced aggregation of citrate-capped gold nanoparticles (AuNPs). Transmission electron microscopy (TEM) and UV-vis absorption spectroscopy were employed to characterize the nanostructures and spectroscopic properties of the Cr3+-AuNP system. The experiment conditions, such as reaction time, pH value, salt concentration and interfering ions, were investigated. The combination of signal amplification of Cr3+-citrate chelation with high sensitivity of RRS technique allow a selective assay of Cr3+ ions with a detection limit of up to 1.0 pM. The overall assay can be carried out at room temperature within only twenty minutes, making it suitable for high-throughput routine applications in environment and food samples.

Chen, Min; Cai, Huai-Hong; Yang, Fen; Lin, Dewen; Yang, Pei-Hui; Cai, Jiye

2014-01-01

340

Graphene-coated microfiber Bragg grating for high-sensitivity gas sensing.  

PubMed

A graphene coated microfiber Bragg grating (GMFBG) for gas sensing is reported in this Letter. Taking advantage of the surface field enhancement and gas absorption of a GMFBG, we demonstrate an ultrasensitive approach to detect the concentration of chemical gas. The obtained sensitivities are 0.2 and 0.5 ppm for NH3 and xylene gas, respectively, which are tens of times higher than that of a GMFBG without graphene for tiny gas concentration change detection. Experimental results indicate that the GMFBG-based NH3 gas sensor has fast response due to its highly compact structure. Such a miniature fiber-optic element may find applications in high sensitivity gas sensing and trace analysis. PMID:24690715

Wu, Yu; Yao, Baicheng; Zhang, Anqi; Rao, Yunjiang; Wang, Zegao; Cheng, Yang; Gong, Yuan; Zhang, Weili; Chen, Yuanfu; Chiang, K S

2014-03-01

341

Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties  

DOEpatents

An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

Pipino, Andrew C. R. (Gaithersburg, MD); Hudgens, Jeffrey W. (Rockville, MD)

1999-08-24

342

Intra-Cavity Total Reflection For High Sensitivity Measurement Of Optical Properties  

DOEpatents

An optical cavity resonator device is provided for conducting sensitive murement of optical absorption by matter in any state with diffraction-limited spatial resolution through utilization of total internal reflection within a high-Q (high quality, low loss) optical cavity. Intracavity total reflection generates an evanescent wave that decays exponentially in space at a point external to the cavity, thereby providing a localized region where absorbing materials can be sensitively probed through alteration of the Q-factor of the otherwise isolated cavity. When a laser pulse is injected into the cavity and passes through the evanescent state, an amplitude loss resulting from absorption is incurred that reduces the lifetime of the pulse in the cavity. By monitoring the decay of the injected pulse, the absorption coefficient of manner within the evanescent wave region is accurately obtained from the decay time measurement.

Pipino, Andrew Charles Rule (Gaithersburg, MD)

1999-11-16

343

Printable highly catalytic Pt- and TCO-free counter electrode for dye-sensitized solar cells.  

PubMed

Here we show that a counter electrode based on carbon network supported Cu2ZnSnS4 nanodots on Mo-coated soda-lime glass for dye-sensitized solar cells can outperform the conventional best electrode with Pt nanoparticles on the fluorine-doped SnO2 conducting glass. In the as-developed electrode, all of the elements are of high abundance ratios with low materials cost. The fabrication is scalable because it is conducted by a screen-printing based approach. Therefore, this research lays a solid ground for the large area fabrication of high-performance dye-sensitized solar cell at reduced material cost. PMID:24467193

He, Jian; Lee, Lawrence Tien Lin; Yang, Shihang; Li, Quan; Xiao, Xudong; Chen, Tao

2014-02-26

344

High sensitivity resonance frequency measurements of individualmicro-cantilevers using fiber optical interferometry  

SciTech Connect

We describe a setup for the resonance frequency measurement of individual microcantilevers. The setup displays both high spatial selectivity and sensitivity to specimen vibrations by utilizing a tapered uncoated fiber tip. The high sensitivity to specimen vibrations is achieved by the combination of optical Fabry-Perot interferometry and narrow band RF detection. Wave fronts reflected on the specimen and on the fiber tip end face interfere, thus no reference plane on the specimen is needed, as demonstrated with the example of freestanding silicon nitride micro-cantilevers. The resulting system is integrated in a DB-235 dual beam FIB system, thereby allowing the measurement of micro-cantilever responses during observation in SEM mode. The FIB was used to modify the optical fiber tip. At this point of our RF system development, the microcantilevers used to characterize the detector were not modified in situ.

Duden, Thomas; Radmilovic, Velimir

2009-03-04

345

Theoretical Consideration of High-Sensitive Biosensor Using Shear Horizontal Acoustic Waves in Layered Structures  

NASA Astrophysics Data System (ADS)

Realization of high sensitive biosensors is required. As an acoustic wave based biosensor can detect immunoreactions, it is expected for applying the biosensor. In this paper, a shear horizontal (SH) acoustic wave in layered structures, namely Love wave, is discussed on the basis of numerical calculations. For generating the Love wave, a 36YX-LiTaO3 is chosen as a piezoelectric substrate. Also, SiO2, polymer, and gold are chosen as guiding layer materials. First, phase velocity and propagation loss are calculated as a function of layer thickness. Then, an additional mass layer is loaded on the guiding layer for simulating bio-layer deposition. The simulated results indicate that high sensitive biosensor is realized by using gold guiding layer.

Kondoh, Jun

346

A high sensitivity ultra-low temperature RF conductance and noise measurement setup  

E-print Network

We report on the realization of a high sensitivity RF noise measurement scheme to study small current fluctuations of mesoscopic systems at milliKelvin temperatures. The setup relies on the combination of an interferometric ampli- fication scheme and a quarter-wave impedance transformer, allowing the mea- surement of noise power spectral densities with GHz bandwith up to five orders of magnitude below the amplifier noise floor. We simultaneously measure the high frequency conductance of the sample by derivating a portion of the signal to a microwave homodyne detection. We describe the principle of the setup, as well as its implementation and calibration. Finally, we show that our setup allows to fully characterize a subnanosecond on-demand single electron source. More generally, its sensitivity and bandwith make it suitable for applications manipulating single charges at GHz frequencies.

Parmentier, Franois D; Denis, Anne; Berroir, Jean-Marc; Glattli, D Christian; Plaais, Bernard; Fve, Gwendal

2010-01-01

347

Development of high-sensitivity accelerometer board for structural health monitoring  

NASA Astrophysics Data System (ADS)

State-of-the-art wireless smart sensor technology enables a dense array of sensors to be distributed through a structure to provide an abundance of structural information. However, the relatively low resolution of the MEMS sensors that are generally adopted for wireless smart sensors limits the network's ability to measure lowlevel vibration often found in the ambient vibration response of building structures. To address this problem, development of a high-sensitivity acceleration board for the Imote2 platform using a low-noise accelerometer is presented. The performance of this new sensor board is validated through extensive laboratory testing. In addition, the use of the high-sensitivity accelerometer board as a reference sensor to improve the capability to capture structural behavior in the smart sensor network is discussed.

Jo, Hongki; Rice, Jennifer A.; Spencer, Billie F., Jr.; Nagayama, Tomonori

2010-04-01

348

Quasi-one-dimensional miniature multiferroic magnetic field sensor with high sensitivity at zero bias field  

NASA Astrophysics Data System (ADS)

A miniature, quasi one dimensional, magnetic field sensor based on magnetoelectric coupling is presented. The magnetoelectric sensor makes use of the d31 coupling mode between a piezoelectric lead zirconate titanate tube and FeNi magnetostrictive wire. The sensors demonstrate high sensitivity, high signal-to-noise ratio, and low noise floor at zero DC magnetic bias field and at low frequency resulting in smaller, lower power consumption, and volumetric efficiency. Experiments indicate a zero bias field sensitivity of 16.5 mV/Oe at 100 Hz stemming from a magnetoelectric coefficient of 1.65 V/cm-Oe. The results are quantitatively described by a theoretical model of laminate composites.

Chen, Yajie; Gillette, Scott M.; Fitchorov, Trifon; Jiang, Liping; Hao, Hongbo; Li, Jiheng; Gao, Xuexu; Geiler, Anton; Vittoria, C.; Harris, V. G.

2011-07-01

349

High Sensitivity Detection of ATP Using Bioluminescence at An Optical Fiber End  

NASA Astrophysics Data System (ADS)

We investigated the sensitivity of ATP detection based on bioluminescence at an optical fiber end where luciferase molecules were immobilized via silica-binding protein molecules. Luminescence was detected by an avalanche photo diode (APD), with coupling optics to make full use of the merit of compactness, high quantum efficiency and low noise of the APD. The core diameter and the numerical aperture of the optical fiber, as well as the design of the coupling optics, were optimized so as to realize high photon-collection efficiency. A detection limit of about 10-10 M was obtained, which corresponds to 10-15 mol of ATP. A rough estimation shows that the photon count rate is still two orders of magnitude lower than that limited by diffusion or reaction processes, implying a possibility of further improvement of the sensitivity.

Iinuma, Masataka; Ushio, Yasuaki; Kuroda, Akio; Kadoya, Yutaka

350

A new rapid and sensitive high-performance liquid chromatographic assay for diclofenac in human plasma.  

PubMed

A new rapid and sensitive reversed-phase HPLC method for the routine analysis of diclofenac in human plasma is described. The method shows high selectivity, sensitivity, and reproducibility employing 4'-methoxydiclofenac as internal standard (IS) with UV-detection at 282 nm. The correlation of peak area ratios (diclofenac/IS) versus diclofenac plasma concentrations are linear between 5.0-2000 ng/ml with a detection limit of 3 ng/ml. Intra- and interday precision studies yielded coefficients of variation < 6.2% for all concentrations (range 20.0-1600 ng/ml). The method was applied for the assay of diclofenac in plasma of healthy volunteers after p.o. and rectal dosage of 50 mg diclofenac sodium and was found to be highly suitable for routine analyses. PMID:7763141

Hanses, A; Spahn-Langguth, H; Mutschler, E

1995-03-01

351

High-sensitivity SrTiO3 photodetectors with paralleled multiple interdigital electrode cells.  

PubMed

We report high-sensitivity SrTiO(3) photoconductive detectors with multiple photoelectric cells connected in parallel. The photocurrent of the detectors increases significantly with an increase of the cell number. The photocurrent responsivity of the detector with three cells can reach 237 mA/W at 10 V bias under illumination of the 375 nm laser, and the corresponding quantum efficiency is 77% at 10 V bias. Furthermore, a transient photovoltaic signal with a rise time of ~490 ps and a full width at half-maximum of ~900 ps is obtained. These results demonstrate that the present devices with further improvement of performance have great potential application in high-sensitivity and ultrafast ultraviolet photodetectors. PMID:23736231

Wang, Le; Jin, Kui-juan; Xing, Jie; Ge, Chen; Lu, Hui-bin; Zhou, Wen-jia; Yang, Guo-zhen

2013-05-20

352

High-sensitive concentration analysis of biochemical liquids using a microfluidic chip fabricated by femtosecond laser  

NASA Astrophysics Data System (ADS)

We demonstrate fabrication of microfluidic chips integrated with optical waveguide embedded in a photostructurable glass for high-sensitive biochemical liquid analysis using a femtosecond laser. Femtosecond laser direct writing followed by annealing and successive wet etching in hydrofluoric acid solution resulted in the rapid manufacturing of microfluidic chips for the biochemical liquid concentration assay. By covering the internal wall of the microfluidic channel in the glass with low refractive index polymer, interaction between the liquid and incident analyzing light is enhanced. Therefore, the microfluidic chip enables us to analyze the low concentrations down to 7.5 mM of protein in bovine serum albumin. Such microfluidic chip realizes the efficient and high-sensitive concentration analysis of biochemical liquids at early stages of biochemical reactions.

Hanada, Y.; Sugioka, K.; Midorikawa, K.

2012-03-01

353

S-phase cells are more sensitive to high-linear energy transfer radiation  

SciTech Connect

S-phase cells are more resistant to low-linear energy transfer (LET) ionizing radiation (IR) than nonsynchronized and G{sub 1}-phase cells, because both nonhomologous end-joining (NHEJ) and homologous recombination repair can repair DNA double-strand breaks (DSBs) in the S phase. Although it was reported 3 decades ago that S-phase cells did not show more resistance to high-LET IR than cells in other phases, the mechanism remains unclear. We therefore attempted to study the phenotypes and elucidate the mechanism involved. Wild-type and NHEJ-deficient cell lines were synchronized using the double-thymidine approach. A clonogenic assay was used to detect the sensitivity of nonsynchronized, synchronized S-phase, and G{sub 2}-phase cells to high- and low-LET IR. The amounts of Ku bound to DSBs in the high- and low-LET-irradiated cells were also examined. S-phase wild-type cells (but not NHEJ-deficient cells) were more sensitive to high-LET IR than nonsynchronized and G{sub 2}-phase cells. In addition, S-phase wild-type cells showed less efficient Ku protein binding to DSBs than nonsynchronized and G{sub 2}-phase cells in response to high-LET IR, although all cells at all phases showed similarly efficient levels of Ku protein binding to DSBs in response to low-LET IR. S-phase cells are more sensitive to high-LET IR than nonsynchronized and G{sub 2}-phase cells, because of the following mechanism: it is more difficult for Ku protein to bind to high-LET IR-induced DNA DSBs in S-phase cells than in cells at other phases, which results in less efficient NHEJ.

Wang, H.; Naidu, M.; Liu, S.; Zhang, P.; Zhang, S.; Wang, H.; Wang, Y.

2009-07-15

354

Effect of Coadministration of Ezetimibe and Simvastatin on High-Sensitivity C-Reactive Protein  

Microsoft Academic Search

This study assessed the effect of ezetimibe coadminis- tered with simvastatin on high-sensitivity C-reactive pro- tein (hs-CRP) in patients with primary hypercholesterol- emia. After dietary stabilization, a 2- to 12-week washout period, and a 4-week, single-blind, placebo lead-in period, patients with baseline low-density li- poprotein cholesterol >145 and <250 mg\\/dl and trig- lycerides <350 mg\\/dl were randomized to one of

Philip T. Sager; Lorenzo Melani; Leslie Lipka; John Strony; Bo Yang; Ramachandran Suresh; Enrico Veltri

2003-01-01

355

Use of phenolic compounds for sensitizing Listeria monocytogenes to high-pressure processing  

Microsoft Academic Search

Three Listeria monocytogenes strains (Scott A, OSY-8578, and OSY-328) that differ considerably in barotolerance were grown to stationary phase and suspended individually in phosphate buffer (pH 7.0). Twelve phenolic compounds, including commercially used food additives, were screened for the ability to sensitize L. monocytogenes to high-pressure processing (HPP). Each L. monocytogenes strain was exposed to each of the 12 phenolic

Mustafa Vurma; Yoon-Kyung Chung; Thomas H. Shellhammer; Evan J. Turek; Ahmed E. Yousef

2006-01-01

356

Improvement of neutron detection efficiency with high sensitive CR39 track detector  

Microsoft Academic Search

Two subjects have been studied for establishing an efficient detection technique applicable to neutrons with an energy higher than 20MeV, for which personnel dosimetry becomes more important especially in space activities and radiation protection around high-energy accelerators.A performance of a new sensitive detector, recently developed copolymer of CR-39 and N-isopropylacrylamide, was checked in a DT neutron field. It was confirmed

K Oda; H Ichijo; N Miyawaki; T Yamauchi; Y Nakane

2001-01-01

357

High Sensitivity InSb Ultra-Thin Film Micro-Hall Sensors for Bioscreening Applications  

Microsoft Academic Search

A high sensitivity, 4.5 \\\\micron 4.5 \\\\micron InSb thin film micro-Hall sensor (micro-HS) with a minimum field detection (Bmin) of 77 nT\\/(Hz)1\\/2 was developed for bioscreening applications and used for the detection of a single 2.8 mum diameter superparamagnetic microbead by monitoring its ac magnetic susceptibility. The scalability of the InSb micro-HS was demonstrated by fabricating 500 nm 500 nm

Adarsh Sandhu; Hideaki Sanbonsugi; Ichiro Shibasaki; Masanori Abe; Hiroshi Handa

2004-01-01

358

High-Sensitivity C-Reactive Protein in Japanese Patients with Type 2 Diabetes  

Microsoft Academic Search

Objective: To assess the relationship between high-sensitivity (HS) C-reactive protein (CRP) and metabolic syndrome (MetS) or atherosclerosis and to assess effects of strict metabolic control on the degree of inflammation and MetS in patients with type 2 diabetes.Research Methods and Procedures: Four hundred thirteen patients with diabetes were enrolled in the cross-sectional study. Of these 413 patients, 161 patients were

Yuji Tajiri; Kazuo Mimura; Fumio Umeda

2005-01-01

359

High-Sensitive Visually Controlled Membrane-Type Quantitation of NAD and Alkaline Phosphatase  

Microsoft Academic Search

New high-sensitive visually controlled membrane-type analytical methods are proposed for quantitation of nicotineamide adenine dinucleotide and alkaline phosphatase in water solutions. The methods are based on using nitrocellulose membrane as a solid matrix on which the components of one-enzyme cofactor regeneration system are being immobilised by adsorption. In the presence of substances to be assayed, the end colored product is

Alexander P. Osipov; Natalia K. Gaponova; Boris B. Dzantiev

1994-01-01

360

A highly reversible and sensitive tyrosinase inhibition-based amperometric biosensor for benzoic acid monitoring  

Microsoft Academic Search

In this present work, a highly reversible and sensitive amperometric biosensor, based on the immobilization of tyrosinase (Tyro) by calcium carbonate nano-materials (nano-CaCO3), was applied for determination of food preservative, benzoic acid. The detection of benzoic acid was performed via its inhibiting action on the Tyro\\/nano-CaCO3 modified glassy carbon electrode. The effects of enzyme substrate type and substrate concentration on

Dan Shan; Qingbo Li; Huaiguo Xue; Serge Cosnier

2008-01-01

361

A high-sensitivity search for X-rays from supernova remnants in Aquila.  

NASA Technical Reports Server (NTRS)

A high-sensitivity scan of the galactic plane from 70 to 30 deg was performed to search for 2-20-keV X rays from supernova remnants. The spectra of five X-ray sources detected between 44 and 31 deg longitude are presented, of which only two might be associated with suggested supernova remnants. Upper limits are given for the 19 possible supernova remnants scanned.

Schwartz, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.; Bleach, R. D.

1972-01-01

362

A high sensitivity search for X-rays from supernova remnants in Aquila  

NASA Technical Reports Server (NTRS)

A high sensitivity scan of the galactic plane was performed to search for 2-20 keV X-rays from supernova remnants. The spectra of five X-ray sources detected between 44 deg and 31 deg longitude, of which only two might be associated with suggested supernova remnants, are reported on. Upper limits are presented for the 19 possible supernova remnants scanned in this survey.

Schwartz, D. A.; Bleach, D. A.; Boldt, E. A.; Holt, S. S.; Serlemitsos, P. J.

1972-01-01

363

Highly sensitive giant magnetoimpedance in a solenoid containing FeCo-based ribbon  

Microsoft Academic Search

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.8B19.2 (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

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

364

Sensitive determination of cinnarizine in human plasma by high performance liquid chromatography and fluorescence detection  

Microsoft Academic Search

A sensitive high performance liquid chromatographic method has been developed for the determination of cinnarizine in human plasma. Cinnarizine and clocinizine (internal standard) were extracted from acidified plasma (pH 4.7) into carbon tetrachloride and the organic layer was evaporated. The products were separated on a Microspher C18 (3 ?m) column, using a mixture of 0.04 % triethylamine in 0.01 M

M. T. Rosseel; R. A. Lefebvre

1993-01-01

365

Dyes designed for high sensitivity detection of double-stranded DNA  

DOEpatents

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a polycationic chain of at least two positive charges. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Albany, CA)

1994-01-01

366

Dyes designed for high sensitivity detection of double-stranded DNA  

DOEpatents

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a cationic chain. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Oakland, CA)

1998-01-01

367

Dyes designed for high sensitivity detection of double-stranded DNA  

DOEpatents

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a cationic chain. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye.

Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Oakland, CA)

2000-01-01

368

Dyes designed for high sensitivity detection of double-stranded DNA  

DOEpatents

Novel fluorescent dyes are provided, characterized by having a fluorophore joined to a cationic chain. The dyes are found to provide for high enhancement upon binding to nucleic acid and have strong binding affinities to the nucleic acid, as compared to the fluorophore without the polycationic chain. The dyes find use in detection of dsDNA in gel electrophoresis and solution at substantially higher sensitivities using substantially less dye. 10 figs.

Glazer, A.N.; Benson, S.C.

1998-07-21

369

High speed spectral domain polarization sensitive optical coherence tomography of the human retina  

Microsoft Academic Search

We developed a high-speed polarization sensitive optical coherence tomography (PS-OCT) system for retinal imaging based on spectral domain OCT. The system uses two spectrometers, one for each polarization channel, that operate in parallel at 20000 A-lines\\/s each. It provides reflectivity, retardation, and cumulative optic axis orientation simultaneously. We present our instrument and discuss the requirements for the alignment of the

Erich Gtzinger; Michael Pircher; Christoph K. Hitzenberger

2005-01-01

370

Development of a Simple and Highly Sensitive Enzyme Immunoassay for Hepatitis C Virus Core Antigen  

Microsoft Academic Search

A highly sensitive enzyme immunoassay (EIA) for the hepatitis C virus (HCV) core antigen (HCVcAg) was developed, and its performance was compared with that of the AMPLICOR HCV test (Roche Molecular Systems). The developed one-step pretreatment method, 30-min incubation of the specimen with a solution containing three different types of detergents (Triton X-100, 3-((3-cholamidopropyl)-dimethylammonio)-1- propanesulfonate (CHAPS), and sodium dodecyl sulfate),

KATSUMI AOYAGI; CHIHARU OHUE; KUMIKO IIDA; TATSUJI KIMURA; EIJI TANAKA; KENDO KIYOSAWA; SHINTARO YAGI

1999-01-01

371

Determination of a ZR Relationship for Snowfall Using a Radar and High Sensitivity Snow Gauges  

Microsoft Academic Search

A best-fit power-law relationship (Z = 427 R1.09) between 1-minute integrated averages of snowfall rate (R) and radar reflectivity factor (Z) was determined on the basis of observations made by using high sensitivity snow gauges (accuracy 0.03 mm h1) and a radar (wavelength 3.2 cm, beamwidth 1.1) of three 1987 Sapporo snowstorms. The relationship Z = 554R0.88, using 30-minute integrated

Yasushi Fujiyoshi; Tatsuo Endoh; Tomomi Yamada; Kazuhisa Tsuboki; Yoshihiro Tachibana; Gorow Wakahama

1990-01-01

372

Cones fabricated by 3D nanoimprint lithography for highly sensitive surface enhanced Raman spectroscopy  

Microsoft Academic Search

We demonstrated a cost-effective and deterministic method of patterning 3D cone arrays over a large area by using nanoimprint lithography (NIL). Cones with tip radius of less than 10 nm were successfully duplicated onto the UV-curable imprint resist materials from the silicon cone templates. Such cone structures were shown to be a versatile platform for developing reliable, highly sensitive surface

Wei Wu; Min Hu; Fung Suong Ou; Zhiyong Li; R. Stanley Williams

2010-01-01

373

Quantitative high-throughput measurement of gene expression with sub-zeptomole sensitivity by capillary electrophoresis  

Microsoft Academic Search

Microarray technologies have provided the ability to monitor the expression of whole genomes rapidly. However, concerns persist with regard to quantitation and reproducibility, and the detection limits for individual genes in particular arrays are generally unknown. This article describes a semiautomated PCR-based technology, Q-RAGE, which rapidly provides measurements of mRNA abundance with extremely high sensitivity using fluorescent detection of specific

Lea Spyres; Sally Gaddis; Ella Bedford; Stacey Arantes; Nikki Liburd; K. Leslie Powell; Howard Thames; David Mitchell; Earl Walborg; Mahmoud Rouabhia; C. Marcelo Aldaz; Michael C. MacLeod

2005-01-01

374

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations  

E-print Network

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 degrees 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 Summer 2014. 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 non-luminous 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 non-thermal 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.

A. U. Abeysekara; R. Alfaro; C. Alvarez; J. D. lvarez; R. Arceo; J. C. Arteaga-Velzquez; H. A. Ayala Solares; A. S. Barber; B. M. Baughman; N. Bautista-Elivar; J. Becerra Gonzalez; E. Belmont; S. Y. BenZvi; D. Berley; M. Bonilla Rosales; J. Braun; R. A. Caballero-Lopez; K. S. Caballero-Mora; A. Carramiana; M. Castillo; U. Cotti; J. Cotzomi; E. de la Fuente; C. De Len; T. DeYoung; R. Diaz Hernandez; L. Diaz-Cruz; J. C. D\\'\\iaz-Vlez; B. L. Dingus; M. A. DuVernois; R. W. Ellsworth; S. F. E.; D. W. Fiorino; N. Fraija; A. Galindo; F. Garfias; M. M. Gonzlez; J. A. Goodman; V. Grabski; M. Gussert; Z. Hampel-Arias; J. P. Harding; C. M. Hui; P. Hntemeyer; A. Imran; A. Iriarte; P. Karn; D. Kieda; G. J. Kunde; A. Lara; R. J. Lauer; W. H. Lee; D. Lennarz; H. Len Vargas; E. C. Linares; J. T. Linnemann; M. Longo; R. Luna-Garcia; A. Marinelli; H. Martinez; O. Martinez; J. Mart\\'\\inez-Castro; J. A. J. Matthews; J. McEnery; E. Mendoza Torres; P. Miranda-Romagnoli; E. Moreno; M. Mostaf; L. Nellen; M. Newbold; R. Noriega-Papaqui; T. Oceguera-Becerra; B. Patricelli; R. Pelayo; E. G. Prez-Prez; J. Pretz; C. Rivire; D. Rosa-Gonzlez; J. Ryan; H. Salazar; F. Salesa; A. Sandoval; M. Schneider; S. Silich; G. Sinnis; A. J. Smith; K. Sparks Woodle; R. W. Springer; I. Taboada; P. A. Toale; K. Tollefson; I. Torres; T. N. Ukwatta; L. Villaseor; T. Weisgarber; S. Westerhoff; I. G. Wisher; J. Wood; G. B. Yodh; P. W. Younk; D. Zaborov; A. Zepeda; H. Zhou; K. N. Abazajian

2014-05-07

375

High sensitivity high resolution double scatter 1-30 MeV gamma ray telescope  

NASA Astrophysics Data System (ADS)

The design and performance of the double-scatter 1-30-MeV gamma-ray telescope developed at the University of California for balloon-borne observations are reported and illustrated with drawings, diagrams, and graphs. The telescope comprises an upper array of 16 6.03 x 6.03 x 100-cm plastic scintillator bars viewed by photomultiplier tubes (PMTs) at both ends, a lower array (at 100-cm distance) of 16 4.83 x 4.83 x 100-cm NaI(Tl) bars viewed at both ends by PMTs, and four 122 x 122 x 0.64-cm plastic sheets viewed by four PMTs each as charged-particle anticoincidence shielding. The operating principle of the telescope, the tests conducted on the NaI(Tl) bars, the on-board data-processing electronics, and the overall performance are characterized. Performance parameters include area 1 sq m, field of view pi sr, 4-sigma sensitivity above 1 MeV 0.00004 gamma/sq cm sec over 25 h, angular resolution about 3.5 deg FWHM, and energy resolution 10 percent at 1 MeV and 6 percent at 6 MeV.

Zych, A. D.; Tumer, O. T.; White, R. S.; Dayton, B.

1983-08-01

376

High sensitivity high resolution double scatter 1-30 MeV gamma ray telescope  

NASA Technical Reports Server (NTRS)

The design and performance of the double-scatter 1-30-MeV gamma-ray telescope developed at the University of California for balloon-borne observations are reported and illustrated with drawings, diagrams, and graphs. The telescope comprises an upper array of 16 6.03 x 6.03 x 100-cm plastic scintillator bars viewed by photomultiplier tubes (PMTs) at both ends, a lower array (at 100-cm distance) of 16 4.83 x 4.83 x 100-cm NaI(Tl) bars viewed at both ends by PMTs, and four 122 x 122 x 0.64-cm plastic sheets viewed by four PMTs each as charged-particle anticoincidence shielding. The operating principle of the telescope, the tests conducted on the NaI(Tl) bars, the on-board data-processing electronics, and the overall performance are characterized. Performance parameters include area 1 sq m, field of view pi sr, 4-sigma sensitivity above 1 MeV 0.00004 gamma/sq cm sec over 25 h, angular resolution about 3.5 deg FWHM, and energy resolution 10 percent at 1 MeV and 6 percent at 6 MeV.

Zych, A. D.; Tumer, O. T.; White, R. S.; Dayton, B.

1983-01-01

377

A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles  

NASA Astrophysics Data System (ADS)

We report on a highly sensitive magnetic biosensor based on the magneto-reactance (MX) effect of a Co65Fe4Ni2Si15B14 amorphous ribbon with a nanohole-patterned surface for detection and quantification of anticancer drugs (Curcumin) tagged to superparamagnetic (Fe3O4) nanoparticles. Fe3O4 nanoparticles (mean size, 10 nm) were first coated with Alginate, and Curcumin was then tagged to the nanoparticles. The detection and quantification of Curcumin were assessed by the change in MX of the ribbon subject to varying concentrations of the Fe3O4 nanoparticles to which Curcumin was tagged. A high capacity of the MX-based biosensor in quantitative analysis of Curcumin-loaded Fe3O4 nanoparticles was achieved in the range of 0-50 ng/ml, beyond which the detection sensitivity of the sensor remained unchanged. The detection sensitivity of the biosensor reached an extremely high value of 30%, which is about 4-5 times higher than that of a magneto-impedance (MI) based biosensor. This biosensor is well suited for detection of low-concentration magnetic biomarkers in biological systems.

Devkota, J.; Wingo, J.; Mai, T. T. T.; Nguyen, X. P.; Huong, N. T.; Mukherjee, P.; Srikanth, H.; Phan, M. H.

2014-05-01

378

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

PubMed

A novel immunochromatographic assay (ICA) was proposed for rapid and multiple assay of ?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 ?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(-1), with the detection limits of 0.20 and 0.040 ng mL(-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 ?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. PMID:25066723

Gao, Hongfei; Han, Jing; Yang, Shijia; Wang, Zhenxing; Wang, Lin; Fu, Zhifeng

2014-08-11

379

Effect of high altitude on sensitivity to the taste of phenylthiocarbamide  

NASA Astrophysics Data System (ADS)

Sensitivity to the taste of phenylthiocarbamide (PTC) was studied using the Harris-Kalmus method in healthy human volunteers at sea level and then subsequently at an altitude of 3500 m over a period of 3 weeks, after which they were brought back to sea level. Blood sugar, insulin and blood cortisol levels were estimated weekly. The results indicated that, out of 51 subjects studied, 26 (55%) were PTC tasters at sea level. Eight of those unable to taste PTC at sea level tested as tasters at high altitude, and 2 of them reverted to being non-tasters on return to sea level. In the blood, an increase in cortisol and blood insulin levels was seen without any significant change in sugar levels. All the changes recorded at high altitude tended to return to basal values after re-induction to sea level. The study suggests that high-altitude hypoxia in some way, possibly involving changes in hormonal profile among other factors, causes an alteration in sensitivity to the taste of PTC, resulting in some of the individuals shifting to lower PTC sensitivity.

Singh, S. B.; Chatterjee, A.; Panjwani, U.; Yadav, D. K.; Selvamurthy, W.; Sharma, K. N.

380

High sensitive/wide dynamic range, field emission pressure sensor based on fully embedded CNTs  

NASA Astrophysics Data System (ADS)

The formation of high sensitivity-wide dynamic range field emission pressure sensors based on carbon nanotubes (CNTs) is reported. In this work, CNTs are grown inside an array of micromachined holes in order to ensure a high sensitivity and a wide dynamic range by allowing anode-cathode proximity while preventing anode-cathode direct contact simultaneously. External pressure is applied to a Si-based flexible anode, which results in consequent variations in emission current, due to electric field changes. Microcavities in this structure have been formed by a Si deep vertical etching process, while the CNTs have been grown by direct current plasma-enhanced chemical vapour deposition. Also, it is demonstrated that a similar fabrication process can be applied to implement a device with an electrically controllable emission current. A high sensitivity of 1.5-13.7 A kPa-1 (with Vanode/cathode < 100 V) within a dynamic range from around 0.1 to 1 GPa, is measured in this experiment.

Taak, S.; Rajabali, S.; Darbari, S.; Mohajerzadeh, S.

2014-01-01

381

Isothermal nucleic acid amplification strategy by cyclic enzymatic repairing for highly sensitive microRNA detection.  

PubMed

Technologies enabling highly sensitive and selective detection of microRNAs (miRNAs) are critical for miRNA discovery and clinical theranostics. Here we develop a novel isothermal nucleic acid amplification technology based on cyclic enzymatic repairing and strand-displacement polymerase extension for highly sensitive miRNA detection. The enzymatic repairing amplification (ERA) reaction is performed via replicating DNA template using lesion bases by DNA polymerase and cleaving the DNA replicate at the lesions by repairing enzymes, uracil-DNA glycosylase, and endonuclease IV, to prime a next-round replication. By utilizing the miRNA target as the primer, the ERA reaction is capable of producing a large number of reporter sequences from the DNA template, which can then be coupled to a cyclic signal output reaction mediated by endonuclease IV. The ERA reaction can be configured as a single-step, close-tube, and real-time format, which enables highly sensitive and selective detection of miRNA with excellent resistance to contaminants. The developed technology is demonstrated to give a detection limit of 0.1 fM and show superb specificity in discriminating single-base mismatch. The results reveal that the ERA reaction may provide a new paradigm for efficient nucleic acid amplification and may hold the potential for miRNA expression profiling and related theranostic applications. PMID:24949808

Zhou, Dian-Ming; Du, Wen-Fang; Xi, Qiang; Ge, Jia; Jiang, Jian-Hui

2014-07-15

382

High Mitochondrial Priming Sensitizes hESCs to DNA-Damage-Induced Apoptosis  

PubMed Central

SUMMARY Human embryonic stem cells (hESCs) are highly sensitive to DNA damage and have low survival ability relative to differentiated cells. We investigated the source of this difference by comparing damage response pathways in hESCs and differentiated cells. We found that hESCs undergo more rapid p53-dependent apoptosis after DNA damage than differentiated cells do. However, p53 localization and function are similar between hESCs and differentiated cells, suggesting that p53 alone cannot explain the difference in sensitivity. Instead, we show that mitochondrial readiness for apoptosis, known as mitochondrial priming, differs between hESCs and differentiated cells. Specifically, the balance between proapoptotic and antiapoptotic proteins is shifted closer to the apoptotic threshold in hESCs than in differentiated cells. Altering this balance in differentiated cells increases their sensitivity and results in cell death, suggesting that manipulation of mitochondrial priming could potentially alter the sensitivity of other stem cells, including cancer stem cells. PMID:23954752

Liu, Julia C.; Guan, Xiao; Ryan, Jeremy A.; Rivera, Ana G.; Mock, Caroline; Agrawal, Vishesh; Letai, Anthony; Lerou, Paul H.; Lahav, Galit

2013-01-01

383

Increased thermal pain sensitivity in animals exposed to chronic high dose Vicodin but not pure hydrocodone.  

PubMed

Vicodin, the combination drug of acetaminophen and the opioid hydrocodone, is one of the most prescribed drugs on the market today. Opioids have demonstrated the ability to paradoxically cause increased pain sensitivity to users in a phenomena called opioid-induced hyperalgesia (OIH). While selected opioids have been shown to produce OIH symptoms in an animal model, hydrocodone and the combination drug Vicodin have yet to be studied. The purpose of this study was to explore the effect of exposure to chronic high dose Vicodin or its components on the sensitivity to both thermal and mechanical pain. Animals were randomly divided into 4 groups, Vicodin, acetaminophen, hydrocodone, or vehicle control, and administered the drug daily for 120 days. Rats were subsequently tested for thermal and mechanical sensitivity. The rats in the Vicodin group displayed a significant decrease in withdrawal time to thermal pain. The rats receiving acetaminophen, hydrocodone, and vehicle showed no statistically significant hypersensitivity in thermal testing. None of the groups demonstrated statistically significant hypersensitivity to mechanical testing. The data suggests Vicodin produces signs of OIH in a rodent model. However, increased pain sensitivity was only noted in the thermal pathway and the hypersensitivity was only seen with the opioid combination drug, not the opioid alone. The results of this study both support the results of previous rodent opioid studies while generating further questions about the specific properties of Vicodin that contribute to pain hypersensitivity. The growing use of Vicodin to treat chronic pain necessitates further research looking into this paradoxical pain response. PMID:25054394

O'Connell, Thomas F; Carpenter, Patrick S; Caballero, Nadia; Putnam, Andrew J; Steere, Joshua T; Matz, Gregory J; Foecking, Eileen M

2014-01-01

384

All-solid-state dye-sensitized solar cells with high efficiency.  

PubMed

Dye-sensitized solar cells based on titanium dioxide (TiO(2)) are promising low-cost alternatives to conventional solid-state photovoltaic devices based on materials such as Si, CdTe and CuIn(1-x)Ga(x)Se(2) (refs 1, 2). Despite offering relatively high conversion efficiencies for solar energy, typical dye-sensitized solar cells suffer from durability problems that result from their use of organic liquid electrolytes containing the iodide/tri-iodide redox couple, which causes serious problems such as electrode corrosion and electrolyte leakage. Replacements for iodine-based liquid electrolytes have been extensively studied, but the efficiencies of the resulting devices remain low. Here we show that the solution-processable p-type direct bandgap semiconductor CsSnI(3) can be used for hole conduction in lieu of a liquid electrolyte. The resulting solid-state dye-sensitized solar cells consist of CsSnI(2.95)F(0.05) doped with SnF(2), nanoporous TiO(2) and the dye N719, and show conversion efficiencies of up to 10.2 per cent (8.51 per cent with a mask). With a bandgap of 1.3 electronvolts, CsSnI(3) enhances visible light absorption on the red side of the spectrum to outperform the typical dye-sensitized solar cells in this spectral region. PMID:22622574

Chung, In; Lee, Byunghong; He, Jiaqing; Chang, Robert P H; Kanatzidis, Mercouri G

2012-05-24

385

High Steroid Sensitivity among Children with Nephrotic Syndrome in Southwestern Nigeria  

PubMed Central

Recent reports from both Caucasian and black populations suggest changes in steroid responsiveness of childhood nephrotic syndrome. This study was therefore undertaken to determine the features and steroid sensitivity pattern of a cohort of black children with nephrotic syndrome. Records of children managed for nephrotic syndrome from January 2008 to April 2013 were reviewed. Details including age, response to treatment, and renal histology were analysed. There were 108 children (median age: 5.9 years, peak: 1-2 years), 90.2% of whom had idiopathic nephrotic syndrome. Steroid sensitivity was 82.8% among children with idiopathic nephrotic syndrome but 75.9% overall. Median time to remission was 7 days. Median age was significantly lower in steroid sensitive compared with resistant patients. The predominant histologic finding in resistant cases was focal segmental glomerulosclerosis (53.3%). No cases of quartan malaria nephropathy or hepatitis B virus nephropathy were diagnosed. Overall mortality was 6.5%. In conclusion, unusually high steroid sensitivity is reported among a cohort of black children. This is likely attributable to the lower age structure of our cohort as well as possible changing epidemiology of some other childhood diseases. Surveillance of the epidemiology of childhood nephrotic syndrome and corresponding modifications in practice are therefore recommended. PMID:25140253

Ladapo, Taiwo Augustina; Esezobor, Christopher Imokhuede; Lesi, Foluso Ebun

2014-01-01

386

Highly sensitive hydrogen sulfide (H?S) gas sensors from viral-templated nanocrystalline gold nanowires.  

PubMed

A facile, site-specific viral-templated assembly method was used to fabricate sensitive hydrogen sulfide (H2S) gas sensors at room temperature. A gold-binding M13 bacteriophage served to organize gold nanoparticles into linear arrays which were used as seeds for subsequent nanowire formation through electroless deposition. Nanowire widths and densities within the sensors were modified by electroless deposition time and phage concentration, respectively, to tune device resistance. Chemiresistive H2S gas sensors with superior room temperature sensing performance were produced with sensitivity of 654%/ppm(v), theoretical lowest detection limit of 2 ppb(v), and 70% recovery within 9 min for 0.025 ppm(v). The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O? plasma treatment followed by an ethanol dip. The template and gold-binding peptide were crucial to electrical and sensor performance. Without surface organics, the resistance fell by several orders of magnitude, the sensitivity dropped by more than a factor of 100 to 6%/ppm(v), the lower limit of detection increased, and no recovery was detected with dry air flow. Viral templates provide a novel, alternative fabrication route for highly sensitive, nanostructured H2S gas sensors. PMID:24598078

Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V; Haberer, Elaine D

2014-04-01

387

Methylation-sensitive high resolution melting (MS-HRM): a new approach for sensitive and high-throughput assessment of methylation  

PubMed Central

In this article, we show that high resolution melting analysis (HRM) is a sensitive and specific method for the detection of methylation. Methylated DNA and unmethylated DNA acquire different sequences after bisulphite treatment resulting in PCR products with markedly different melting profiles. We used PCR to amplify both methylated and unmethylated sequences and assessed HRM for the determination of the methylation status of the MGMT promoter region. Reconstruction experiments showed that MGMT methylation could be detected at levels as low as 0.1%. Moreover, MS-HRM allows for estimation of the methylation level by comparing the melting profiles of unknown PCR products to the melting profiles of PCR products derived from standards with a known unmethylated to methylated template ratio. We used MS-HRM for the analysis of eight cell lines of known methylation status and a panel of colorectal cancer specimens. The simplicity and high reproducibility of the MS-HRM protocol makes MS-HRM the method of choice for methylation assessment in many diagnostic and research applications. PMID:17289753

Dobrovic, Alexander

2007-01-01

388

High-sensitivity explosives detection using dual-excitation-wavelength resonance-Raman detector  

NASA Astrophysics Data System (ADS)

A key challenge for standoff explosive sensors is to distinguish explosives, with high confidence, from a myriad of unknown background materials that may have interfering spectral peaks. To meet this challenge a sensor needs to exhibit high specificity and high sensitivity in detection at low signal-to-noise ratio levels. We had proposed a Dual-Excitation- Wavelength Resonance-Raman Detector (DEWRRED) to address this need. In our previous work, we discussed various components designed at WVHTCF for a DEWRRED sensor. In this work, we show a completely assembled laboratory prototype of a DEWRRED sensor and utilize it to detect explosives from two standoff distances. The sensor system includes two novel, compact CW deep-Ultraviolet (DUV) lasers, a compact dual-band high throughput DUV spectrometer, and a highly-sensitive detection algorithm. We choose DUV excitation because Raman intensities from explosive traces are enhanced and fluorescence and solar background are not present. The DEWRRED technique exploits the excitation wavelength dependence of Raman signal strength, arising from complex interplay of resonant enhancement, self-absorption and laser penetration depth. We show measurements from >10 explosives/pre-cursor materials at different standoff distances. The sensor showed high sensitivity in explosive detection even when the signalto- noise ratio was close to one (~1.6). We measured receiver-operating-characteristics, which show a clear benefit in using the dual-excitation-wavelength technique as compared to a single-excitation-wavelength technique. Our measurements also show improved specificity using the amplitude variation information in the dual-excitation spectra.

Yellampalle, Balakishore; McCormick, William B.; Wu, Hai-Shan; Sluch, Mikhail; Martin, Robert; Ice, Robert V.; Lemoff, Brian

2014-05-01

389

Design Parameter Sensitivity Analysis of High-Speed Motorized Spindle Systems Considering High-Speed Effects  

Microsoft Academic Search

With increasing demands for higher productivity and lower production costs, high-speed machine tools have been widely utilized in the modern production facilities. Meanwhile, to meet the requirements of higher spindle speeds and more versatile machining capabilities, it is becoming necessary for engineers to thoroughly realize how the spindle system design would influence the system dynamics with considering highspeed effects. With

Chi-Wei Lin

2007-01-01

390

Highly sensitive antenna using inkjet overprinting with particle-free conductive inks.  

PubMed

Printed antennas with low signal losses and fast response in high-frequency bands have been required. Here we reported on highly sensitive antennas using additive patterning of particle-free metallo-organic decomposition silver inks. Inkjet overprinting of metallo-organic decomposition inks onto copper foil and silver nanowire line produced antenna with mirror surfaces. As a result, the overprinted antennas decreased their return losses at 0.5-4.0 GHz and increased the speed of data communication in WiFi network. PMID:23075475

Komoda, Natsuki; Nogi, Masaya; Suganuma, Katsuaki; Otsuka, Kanji

2012-11-01

391

A Small-Field, High-Sensitivity Focusing Schlieren System for Flowfield Visualization  

NASA Astrophysics Data System (ADS)

The focusing Schlieren technique has been used worldwide for flow visualization because it produces a global, easily-interpretable image of the refractive-index-gradient fields of large dimensions. A very high sensitivity (less than 2 arcseconds) focusing Schlieren system was designed and constructed for application to the NASA Langley High-speed Flow Generator (HFG). The HFG system produces a low-density fast flow and operates as a free jet expansion. The shock and boundary layers produced by an obstacle in the supersonic flow-field can be visualized. The qualitative and quantitative results of the flowfield visualization will be presented.

Spraggins, Darrell A.; Tabibi, Bagher M.; Lee, Ja H.; Weinstein, Leonard M.

1996-11-01

392

Performance Sensitivity Studies on the PIAA Implementation of the High-Contrast Imaging Testbed  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the sensitivity studies on the Phase-Induced Amplitude Apodization (PIAA), or pupil mapping using the High-Contrast Imaging Testbed (HCIT). PIAA is a promising technique in high-dynamic range stellar coronagraph. This presentation reports on the investigation of the effects of the phase and rigid-body errors of various optics on the narrowband contrast performance of the PIAA/HCIT hybrid system. The results have shown that the 2-step wavefront control method utilizing 2-DMs is quite effective in compensating the effects of realistic phase and rigid-body errors of various optics

Sidick, Erkin; Lou, John; Shaklan, Stuart; Levine, Marie

2010-01-01

393

From maps to movies: High resolution time-varying sensitivity analysis for spatially distributed watershed models  

NASA Astrophysics Data System (ADS)

Distributed watershed models are now widely used in practice to simulate runoff responses at high spatial and temporal resolutions. Counter to this purpose, diagnostic analyses of distributed models currently aggregate performance measures in space and/or time and are thus disconnected from the models' operational and scientific goals. To address this disconnect, this study contributes a novel approach for computing and visualizing time-varying global sensitivity indices for spatially distributed model parameters. The high-resolution model diagnostics employ the method of Morris to identify evolving patterns in dominant model processes at sub-daily timescales over a six-month period. The method is demonstrated on the United States National Weather Service's Hydrology Laboratory Research Distributed Hydrologic Model (HL-RDHM) in the Blue River watershed, Oklahoma, USA. Three hydrologic events are selected from within the six-month period to investigate the patterns in spatiotemporal sensitivities that emerge as a function of forcing patterns as well as wet-to-dry transitions. Surprisingly, events with similar magnitudes and durations exhibit significantly different performance controls in space and time, indicating that the diagnostic inferences drawn from representative events will be heavily biased by the a priori selection of those events. By contrast, this study demonstrates high-resolution time-varying sensitivity analysis, requiring no assumptions regarding representative events and allowing modelers to identify transitions between modeled hydrologic regimes a posteriori. The proposed approach details the dynamics of parameter sensitivity in nearly continuous time, providing critical diagnostic insights into the underlying model processes driving predictions. Furthermore, the approach offers the potential to identify transition points between hydrologic regimes under nonstationarity.

Herman, J. D.; Kollat, J. B.; Reed, P. M.; Wagener, T.

2013-12-01

394

From maps to movies: high resolution time-varying sensitivity analysis for spatially distributed watershed models  

NASA Astrophysics Data System (ADS)

Distributed watershed models are now widely used in practice to simulate runoff responses at high spatial and temporal resolutions. Counter to this purpose, diagnostic analyses of distributed models currently aggregate performance measures in space and/or time and are thus disconnected from the models' operational and scientific goals. To address this disconnect, this study contributes a novel approach for computing and visualizing time-varying global sensitivity indices for spatially distributed model parameters. The high-resolution model diagnostics employ the method of Morris to identify evolving patterns in dominant model processes at sub-daily timescales over a six-month period. The method is demonstrated on the United States National Weather Service's Hydrology Laboratory Research Distributed Hydrologic Model (HL-RDHM) in the Blue River watershed, Oklahoma, USA. Three hydrologic events are selected from within the six-month period to investigate the patterns in spatiotemporal sensitivities that emerge as a function of forcing patterns as well as wet-to-dry transitions. Surprisingly, events with similar magnitudes and durations exhibit significantly different performance controls in space and time, indicating that the diagnostic inferences drawn from representative events will be heavily biased by the a priori selection of those events. By contrast, this study demonstrates high-resolution time-varying sensitivity analysis, requiring no assumptions regarding representative events and allowing modelers to identify transitions between modeled hydrologic regimes a posteriori. The proposed approach details the dynamics of parameter sensitivity in nearly continuous time, providing critical diagnostic insights into the underlying model processes driving predictions. Furthermore, the approach offers the potential to identify transition points between hydrologic regimes under nonstationarity.

Herman, J. D.; Kollat, J. B.; Reed, P. M.; Wagener, T.

2013-08-01

395

Two-dimensional array of cold-electron bolometers for high-sensitivity polarization measurements  

NASA Astrophysics Data System (ADS)

A new concept of a two-dimensional array of cold-electron bolometers with distributed dipole antennas in the focal plane for high-sensitivity polarization measurements is proposed. The concept gives a unique combination of high polarization resolution due to a large uniforms array of cold-electron bolometers and optimal matching with junction field effect transistor (JFET) amplifiers because of flexibility in direct-current connections. The noise characteristics are improved due to arriving-signal power distribution among numerous cold-electron bolometers and an increase in their response. This should lead to a significant increase in the sensitivity and dynamic range compared with competing alternative bolometer technologies. The reliability of the twodimensional array significantly increases due to a series-parallel connection of a large number of cold-electron bolometers. High polarization resolution should be ensured due to uniform covering of a substrate by a two-dimensional array over a large area and the absence of the beam compression to small lumped elements. The fundamental sensitivity limit of the cold-electron bolometer array is smaller than photon noise which is considered to be the ultimate level restricted by the background radiation. Estimates of noise of bolometers with the JFET reading system show the possibility of realizing the ultimate sensitivity below the photon-noise level 5 ?10-17 W/Hz1/2 at a frequency of 350 GHz for an optical load with a power of 5 pW. These parameters correspond to the requirements to the receiving system of a BOOMERanG balloon telescope.

Kuzmin, L. S.

2012-01-01

396

Development of a low-power high-sensitivity cloud profiling FM-CW radar at 95 GHz  

Microsoft Academic Search

We developed a low-power and high-sensitivity cloud profiling radar transmitting frequency-modulated continuous waves (FM-CW) at 95 GHz for ground-based observations. Millimeter waves at 95 GHz are used to realize high sensitivity to small cloud particles. An FM-CW type radar realizes similar sensitivity with much smaller output power than a pulse type radar. Two 1 m-diameter parabolic antennas, separated by 1.4

Toshiaki TAKANO; Ken-ichi AKITA; Hiroshi KUBO; Youhei KAWAMURA; Hiroshi KUMAGAI; Tamio TAKAMURA; Yuji NAKANISHI; Teruyuki NAKAJIMA

2004-01-01

397

High-sensitivity electro-optic CO2 gas sensing based on absorption spectroscopy  

NASA Astrophysics Data System (ADS)

We reported a high-sensitivity CO2 gas sensing system based on wavelength scanning absorption spectroscopy. A distributed feedback (DFB) laser was used as the light source in the system, whose wavelength was thermally tuned, by a thermoelectric cooler (TEC), to scan around one CO2 absorption line near 1572nm. Scanning of the absorption line spectrum is performed over a glass CO2 gas cell, 16.5 cm long with collimated optical fiber connectors. Different concentrations of CO2 were prepared by a high-precision gas flow control meter and sealed within the gas cell. A self-designed detection and amplification circuit was employed for absorption spectrum detection. The circuit implements background-cancellation with a two tier amplification scheme. By cancelling the high background signal, we can improve the CO2 sensitivity by about two orders of magnitude compared with commonly used direct detection methods with high background signals. Reducing the high DC signal permits isolated amplification of the absorption line spectrum. Absorption spectra of different CO2 concentrations were measured, and the results demonstrated sensing capability of 100% to <0.1% concentrations of CO2. This sensing system is expected to be used in conjunction with a wireless CO2 sensor network for large area CO2 monitoring. Given the very lower power consumption of the DFB laser and the detection circuit this sensing system offers a solution for affordable long term CO2 monitoring for reliable storage in carbon sequestration.

Zhang, Scott N.; Wang, Dorothy Y.; Gong, Jianmin; Fan, Dian; Dong, Bo; Fraser, Michael; Wang, Anbo

2012-06-01

398

Capillary electrophoresis mass spectrometry with sheathless electrospray ionization for high sensitivity analysis of underivatized amino acids.  

PubMed

A high durability sheathless electrospray ionization interface of CE-MS is applied for the sensitive analysis of underivatized amino acids. The sheathless interface was realized using an ionophore membrane-packed electro-conduction channel. The interface functioned well with a volatile alkaline background electrolyte (BGE) and uncoated fused-silica capillaries for CE-MS analysis of underivatized amino acids. High electroosmotic flow with alkaline BGE facilitated high separation efficiency (>100,000 theoretical plates) and short analysis time (<15 min). Both the short-term stability and long-term durability are particularly suited for routine applications. Using electrokinetic injection and the multiple reaction monitoring (MRM) mode with a triple-quadrupole analyzer, high sensitivity was achieved, which yielded detection limits of 0.05-0.81 ?M. For the quantitation of underivatized amino acids, quantification precisions (RSDs) for intra- and inter-day analyses were less than 3%. Recoveries from serum were 96.3-101.8% for isotope dilution mass spectrometry (IDMS). When compared with HPLC-IDMS for human serum samples, highly agreeable (96.9-102.0%) results were obtained with the proposed CE-IDMS method. PMID:22821486

Jeong, Ji-Seon; Kim, Sook-Kyung; Park, Sang-Ryoul

2012-07-01

399

Cerebral blood flow recorded at high sensitivity in two dimensions using high resolution optical imaging  

Microsoft Academic Search

1. ABSTRACT Knowledge about sensory-evoked blood-fl ow changes is es- sential for constraining hemodynamic response models used to interpret functional brain imaging signals, such as fMRI. Here, we extracted 2-dimensional blood-flow and its tempo- ral modulations from high-resolution optical imaging data in the awake monkey. Optical imaging allows to track moving erythrocytes (or small clusters thereof), thus providing, albeit noisy,

Ivo Vanzetta; Thomas Deneux; Guillaume S. Masson; Olivier D. Faugeras

2006-01-01

400

Development of novel optical fiber interferometric sensors with high sensitivity for acoustic emission detection  

NASA Astrophysics Data System (ADS)

For the purpose of developing a new highly-sensitive and reliable fiber optical acoustic sensor capable of real-time on-line detection of acoustic emissions in power transformers, this dissertation presents the comprehensive research work on the theory, modeling, design, instrumentation, noise analysis, and performance evaluation of a diaphragm-based optical fiber acoustic (DOFIA) sensor system. The optical interference theory and the diaphragm dynamic vibration analysis form the two foundation stones of the diaphragm-based optical fiber interferometric acoustic (DOFIA) sensor. Combining these two principles, the pressure sensitivity and frequency response of the acoustic sensor system is analyzed quantitatively, which provides guidance for the practical design for the DOFIA sensor probe and system. To meet all the technical requirements for partial discharge detection, semiconductor process technologies are applied, for the first time to our knowledge, in fabricating the micro-caved diaphragm (MCD) used for the DOFIA sensor probe. The novel controlled thermal bonding method was proposed, designed, and developed to fabricate high performance DOFIA sensor probes with excellent mechanical strength and temperature stability. In addition, the signal processing unit is designed and implemented with high gain, wide band response, and ultra low noise. A systematic noise analysis is also presented to provide a better understanding of the performance limitations of the DOFIA sensor system. Based on the system noise analysis results, optimization measures are proposed to improve the system performance. Extensive experiments, including the field testing in a power transformer, have also been conducted to systematically evaluate the performance of the instrumentation systems and the sensor probes. These results clearly demonstrated the feasibility of the developed DOFIA sensor for the detection of partial discharges inside electrical power transformers, with unique advantages of non-electrically conducting, high sensitivity, high frequency response, and immunity to the electro-magnetic interference (EMI).

Deng, Jiangdong

401

FBG sensor for temperature-independent high sensitive pressure measurement with aid of a Bourdon tube  

NASA Astrophysics Data System (ADS)

A temperature independent high sensitive pressure sensing system using fiber Bragg grating (FBG) and `C' shaped Bourdon tube (CBT) is demonstrated. The sensor is configured by firmly fixing the FBG (FBG1) between free and fixed ends of the CBT. Additional FBG (FBG2) in line to the FBG1 is introduced which is shielded from the external pressure, tend to measure only the ambient temperature fluctuations. The CBT has an elliptical cross section where its free end is sealed and the fixed end is open for subjecting the liquid or gas pressure to be measured. With the application of pressure, the free end of CBT tends to straighten out results in an axial strain in FBG1 causes red shift in Bragg wavelength. The pressure can be determined by measuring the shift of the Bragg wavelength. The experimental pressure sensitivity is found to be 66.9 pm/psi over a range of 0 to 100 psi. The test results show that the Bragg wavelength shift is linear corresponds to change in applied pressure and well agreed with the simulated results. This simple and high sensitive design is capable of measuring static/dynamic pressure and temperature simultaneously which suits for industrial applications.

Srimannarayana, K.; Vengal Rao, P.; Sai Shankar, M.; Kishore, P.

2014-05-01

402

High-throughput screening of human leukemia xenografts to identify dexamethasone sensitizers.  

PubMed

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy. Glucocorticoids (e.g., dexamethasone) form a critical component of chemotherapy regimens for pediatric ALL, and the initial response to glucocorticoid therapy is a major prognostic factor, where resistance is predictive of poor outcome. We have previously established a clinically relevant ALL xenograft model, consisting of primary pediatric ALL biopsies engrafted into immune-deficient mice, in which in vitro and in vivo dexamethasone sensitivity significantly correlated with patient outcome. In this study, we used high-throughput screening (HTS) to identify novel compounds that reverse dexamethasone resistance in a xenograft (ALL-19) derived from a chemoresistant pediatric ALL patient that is representative of the most common pediatric ALL subtype (B-cell precursor [BCP-ALL]). The compound 2-(4-chlorophenoxy)-2-methyl-N-(2-(piperidin-1-yl)phenyl)propanamide showed little cytotoxic activity alone (IC50 = 31 M), but when combined with dexamethasone, it caused a marked decrease in cell viability. Fixed-ratio combination assays were performed against a broad panel of dexamethasone-resistant and -sensitive xenografts representative of BCP-ALL, T-cell ALL, and Mixed Lineage Leukemia-rearranged ALL, and synergy was observed in six of seven xenografts. We describe here the development of a novel 384-well cell-based high-throughput screening assay for identifying potential dexamethasone sensitizers using a clinically relevant ALL xenograft model. PMID:25104793

Toscan, Cara E; Failes, Tim; Arndt, Greg M; Lock, Richard B

2014-12-01

403

Highly sensitive integrated pressure sensor with horizontally oriented carbon nanotube network  

PubMed Central

This paper presents a functionalized, horizontally oriented carbon nanotube network as a sensing element to enhance the sensitivity of a pressure sensor. The synthesis of horizontally oriented nanotubes from the AuFe catalyst and their deposition onto a mechanically flexible substrate via transfer printing are studied. Nanotube formation on thermally oxidized Si (100) substrates via plasma-enhanced chemical vapor deposition controls the nanotube coverage and orientation on the flexible substrate. These nanotubes can be simply transferred to the flexible substrate without changing their physical structure. When tested under a pressure range of 0 to 50 kPa, the performance of the fabricated pressure sensor reaches as high as approximately 1.68%/kPa, which indicates high sensitivity to a small change of pressure. Such sensitivity may be induced by the slight contact in isolated nanotubes. This nanotube formation, in turn, enhances the modification of the contact and tunneling distance of the nanotubes upon the deformation of the network. Therefore, the horizontally oriented carbon nanotube network has great potential as a sensing element for future transparent sensors. PMID:24472487

2014-01-01

404

Determination of Chlorinated Hydrocarbons in Water Using Highly Sensitive Mid-Infrared Sensor Technology  

PubMed Central

Chlorinated aliphatic hydrocarbons and chlorinated aromatic hydrocarbons (CHCs) are toxic and carcinogenic contaminants commonly found in environmental samples, and efficient online detection of these contaminants is still challenging at the present stage. Here, we report an advanced Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) sensor for in-situ and simultaneous detection of multiple CHCs, including monochlorobenzene, 1,2-dichlorobenzene, 1,3-dichlorobenzene, trichloroethylene, perchloroethylene, and chloroform. The polycrystalline silver halide sensor fiber had a unique integrated planar-cylindric geometry, and was coated with an ethylene/propylene copolymer membrane to act as a solid phase extractor, which greatly amplified the analytical signal and contributed to a higher detection sensitivity compared to the previously reported sensors. This system exhibited a high detection sensitivity towards the CHCs mixture at a wide concentration range of 5~700?ppb. The FTIR-ATR sensor described in this study has a high potential to be utilized as a trace-sensitive on-line device for water contamination monitoring. PMID:23982222

Lu, Rui; Mizaikoff, Boris; Li, Wen-Wei; Qian, Chen; Katzir, Abraham; Raichlin, Yosef; Sheng, Guo-Ping; Yu, Han-Qing

2013-01-01

405

Highly sensitive nano-porous lattice biosensor based on localized surface plasmon resonance and interference.  

PubMed

We propose a design for a highly sensitive biosensor based on nanostructured anodized aluminum oxide (AAO) substrates. A gold-deposited AAO substrate exhibits both optical interference and localized surface plasmon resonance (LSPR). In our sensor, application of these disparate optical properties overcomes problems of limited sensitivity, selectivity, and dynamic range seen in similar biosensors. We fabricated uniform periodic nanopore lattice AAO templates by two-step anodizing and assessed their suitability for application in biosensors by characterizing the change in optical response on addition of biomolecules to the AAO template. To determine the suitability of such structures for biosensing applications, we immobilized a layer of C-reactive protein (CRP) antibody on a gold coating atop an AAO template. We then applied a CRP antigen (Ag) atop the immobilized antibody (Ab) layer. The shift in reflectance is interpreted as being caused by the change in refractive index with membrane thickness. Our results confirm that our proposed AAO-based biosensor is highly selective toward detection of CRP antigen, and can measure a change in CRP antigen concentration of 1 fg/ml. This method can provide a simple, fast, and sensitive analysis for protein detection in real-time. PMID:22109166

Yeom, Se-Hyuk; Kim, Ok-Geun; Kang, Byoung-Ho; Kim, Kyu-Jin; Yuan, Heng; Kwon, Dae-Hyuk; Kim, Hak-Rin; Kang, Shin-Won

2011-11-01

406

High-Sensitivity Atomic Magnetometer Unaffected by Spin-Exchange Relaxation J. C. Allred and R. N. Lyman  

E-print Network

High-Sensitivity Atomic Magnetometer Unaffected by Spin-Exchange Relaxation J. C. Allred and R. N; published 9 September 2002) Alkali-metal magnetometers compete with SQUID detectors as the most sensitive demonstrate a K magnetometer in which spin-exchange relaxation is completely eliminated by operating at high K

Romalis, Mike

407

Optimization of X-ray phase contrast imaging system toward high-sensitivity measurements of biological organs  

SciTech Connect

X-ray phase contrast imaging and tomography using a Talbot grating interferometer is currently available for user experiments at BL20B2 in SPring-8. The measurement condition for X-ray phase contrast tomography has been optimized to achieve high-sensitivity measurements of biological soft tissues and organs. Some biological samples were measured to demonstrate the high-sensitivity imaging.

Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8) (Japan)

2012-07-31

408

Faster and Active Surveillance of Hospital-Acquired Infections: A Model for Settings with High Sensitivity Predictors  

Microsoft Academic Search

Background: At present, passive alarm system from culture reports and announced from groups outbreak events make cases investigate delayed. Is there any predict factor can be used to suggest active high capture sensitivity surveillance and alarm outbreak early? Objectives: Is there any predict factor can be used to get active high capture sensitivity surveillance of hospital-acquired infections (HAI) in acute

Yao-wen Chung; Yu-sheng Lo; Wen-sen Lee; Min-huei Hsu; Chien-tsai Liu

2009-01-01

409

A high-sensitivity OH 5-cm line survey in late-type stars  

E-print Network

We have undertaken a comprehensive search for 5-cm excited OH maser emission from evolved stars representative of various stages of late stellar evolution. Observed sources were selected from known 18-cm OH sources. This survey was conducted with the 100-m Effelsberg telescope to achieve high signal to noise ratio observations and a sensitivity limit of about 0.05 to 0.1 Jy. A total of 64 stellar sources were searched for both main line and satellite line emission. We confirm the previous detection of 5 cm OH in Vy 2-2, do not confirm emission from NML-Cyg and do not report any other new detection within the above sensitivity limit. Implications of these results on the pumping mechanism of the OH radical in circumstellar envelopes are briefly discussed.

J. -F. Desmurs; A. Baudry; P. Sivagnanam; C. Henkel

2002-10-07

410

Development of a highly sensitive chemiluminescence enzyme immunoassay using enhanced luminol as substrate.  

PubMed

In this study, a high sensitivity chemiluminescence enzyme immunoassay (CLEIA) based on novel enhancers was developed. Under optimal conditions, we developed an enhanced chemiluminescence reaction (ECR) catalyzed by horseradish peroxidase (HRP-C) in the presence of 3-(10'-phenothiazinyl) propane-1-sulfonate (SPTZ) and 4-morpholinopyridine (MORP) as enhancers. The limit of detection of the newly prepared chemiluminescent cocktail for HRP was 0.33?pg/well, which is lower than that of commercial Super Signal substrate. The results showed that this novel chemiluminescent cocktail can significantly increase the light output of HRP-catalyzed ECR, which can be translated into a corresponding improvement in sensitivity. Similar improvements were observed in CLEIA for the determination of chloramphenicol in milk. In addition, the ECR of N-azoles as secondary enhancer was also presented. PMID:23785024

Tao, Xiaoqi; Wang, Wenjun; Wang, Zhanhui; Cao, Xingyuan; Zhu, Jinghui; Niu, Lanlan; Wu, Xiaoping; Jiang, Haiyang; Shen, Jianzhong

2014-06-01

411

A highly sensitive ethanol sensor based on mesoporous ZnO-SnO2 nanofibers  

PubMed Central

A facile and versatile method for the large-scale synthesis of sensitive mesoporous ZnOSnO2 (m-ZS) nanofibers through a combination of surfactant-directed assembly and an electrospinning approach is reported. The morphology and the structure were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), x-ray diffraction (XRD), and nitrogen adsorptiondesorption isotherm analysis. The results showed that the diameters of fibers ranged from 100 to 150 nm with mixed structures of wurtzite (ZnO) and rutile (SnO2), and a mesoporous structure was observed in the m-ZS nanofibers. The sensor performance of the prepared m-ZS nanofibers was measured for ethanol. It is found that the mesoporous fiber film obtained exhibited excellent ethanol sensing properties, such as high sensitivity, quick response and recovery, good reproducibility, and linearity in the range 3500 ppm. PMID:19417420

Song, Xiaofeng; Wang, Zhaojie; Liu, Yongben; Wang, Ce; Li, Lijuan

2009-01-01

412

Building highly sensitive dye assemblies for biosensing from molecular building blocks  

PubMed Central

Fluorescence superquenching is investigated for polyelectrolytes consisting of cyanine dye pendant polylysines ranging in number of polymer repeat units (NPRU) from 1 to 900, both in solution and after adsorption onto silica nanoparticles. As NPRU increases, the absorption and fluorescence evolve from monomer spectra to red-shifted features indicative of molecular J aggregates. In solution, the superquenching sensitivity toward an anionic electron acceptor increases by more than a millionfold over the NPRU range from 1 to 900. The dramatic increase is attributed to enhanced equilibrium constants for binding the quenchers, and the amplified quenching of a delocalized exciton of ?100 polymer repeat units. The self-assembly of monomer onto silica and clay nanoparticles leads to formation of J aggregates, and surface-activated superquenching enhanced 10,000 over the monomer in solution, indicating the formation of self-assembled polymers on the nanoparticle surface. Utilization of these self-assembled polymers as high-sensitivity biosensors is demonstrated. PMID:11742082

Jones, Robert M.; Lu, Liangde; Helgeson, Roger; Bergstedt, Troy S.; McBranch, Duncan W.; Whitten, David G.

2001-01-01

413

High Sensitive Precise 3D Accelerometer for Solar System Exploration with Unmanned Spacecrafts  

NASA Astrophysics Data System (ADS)

Solutions of several space and geophysical tasks require creating high sensitive precise accelerometers with sensitivity in order of 10 -13 g. These several tasks are following: inertial navigation of the Earth and Space; gravimetry nearby the Earth and into Space; geology; geophysics; seismology etc. Accelerometers (gravimeters and gradientmeters) with required sensitivity are not available now. The best accelerometers in the world have sensitivity worth on 4-5 orders. It has been developed a new class of fiber-optical sensors (FOS) with light pulse modulation. These sensors have super high threshold sensitivity and wide (up to 10 orders) dynamic range, and can be used as a base for creating of measurement units of physical values as 3D superhigh sensitive precise accelerometers of linear accelerations that is suitable for highest requirements. The principle of operation of the FOS is organically combined with a digital signal processing. It allows decreasing hardware of the accelerometer due to using a usual air-borne or space-borne computer; correcting the influence of natural, design, technological drawbacks of FOS on measured results; neutralising the influence of extraordinary situations available during using of FOS; decreasing the influence of internal and external destabilising factors (as for FOS), such as oscillation of environment temperature, instability of pendulum cycle frequency of sensitive element of the accelerometer etc. We were conducted a quantitative estimation of precise opportunities of analogue FOS in structure of fiber optical measuring devices (FOMD) for elementary FOMD with analogue FOS built on modern element basis of fiber optics (FO), at following assumptions: absolute parameter stability of devices of FOS measuring path; single transmission band of registration path; maximum possible inserted in optical fiber (OF) a radiated power. Even at such idealized assumptions, a calculated value in limit reached minimum inaccuracy of measuring, by analogue FOS, has been 10-4 %. Substantially accessible values are yet worse on 2-3 order. The reason of poor precise performances of measurers on the basis of analogue FOS is metrologically poor quality of a stream of optical radiation carrying out role of the carrier and receptor of the information. It is a high level of photon noise and a small blanket intensity level. First reason reflects the fact of discreteness of flow of high-energy photons, and it is consequence of second one - smallness, on absolute value, of inserted power into OF from available radiation sources (RS). Works on improvement of FO elements are carrying out. Certainly, it will be created RS allow to insert enough of power into standard OF. But simple increasing of optical flow power in measuring path of FOS will not be able to decide radically the problem of increasing of measuring prices: with raising of power in proportion of square root of its value there is raising a power of photon noises - 1000-times increase of power promises only 30-times increase of measuring precise; insertion into OF more large power ( 1 W for standard silicon OF) causes an appearance of non-linear effects in it, which destroying an operating principle of analogue FOS. Thus, it is needed to constatate impossibility of building, at that time, measurers of analogue FOS, concurated with traditional (electrical) measurers on measuring precise. At that all, advantages of FO, as basis of building of FO MD requires to find ways for decision of these problems. Analysis of problem of sensitivity of usual (analogue) FOS has brought us to conclusion about necessity of reviewing of principles of information signal forming in FOS and principles its next electronic processing. For radical increasing of accuracy of measurements with using FOS it is necessary to refuse analogue modulation of optical flow and to transfer to discreet its modulations, entering thus in optical flow new, non-optical, parameters, which will serve as recipients of the information. It allows to save up all advantages of FOS (carrier of in

Savenko, Y. V.; Demyanenko, P. O.; Zinkovskiy, Y. F.

414

Highly sensitive and selective odorant sensor using living cells expressing insect olfactory receptors  

PubMed Central

This paper describes a highly sensitive and selective chemical sensor using living cells (Xenopus laevis oocytes) within a portable fluidic device. We constructed an odorant sensor whose sensitivity is a few parts per billion in solution and can simultaneously distinguish different types of chemicals that have only a slight difference in double bond isomerism or functional group such as ?OH, ?CHO and ?C(?O)?. We developed a semiautomatic method to install cells to the fluidic device and achieved stable and reproducible odorant sensing. In addition, we found that the sensor worked for multiple-target chemicals and can be integrated with a robotic system without any noise reduction systems. Our developed sensor is compact and easy to replace in the system. We believe that the sensor can potentially be incorporated into a portable system for monitoring environmental and physical conditions. PMID:20798064

Misawa, Nobuo; Mitsuno, Hidefumi; Kanzaki, Ryohei; Takeuchi, Shoji

2010-01-01

415

A Small Mission Featuring an Imaging X-ray Polarimeter with High Sensitivity  

NASA Technical Reports Server (NTRS)

We present a detailed description of a small mission capable of obtaining high precision and meaningful measurement of the X-ray polarization of a variety of different classes of cosmic X-ray sources. Compared to other ideas that have been suggested this experiment has demonstrated in the laboratory a number of extremely important features relevant to the ultimate selection of such a mission by a funding agency. The most important of these questions are: 1) Have you demonstrated the sensitivity to a polarized beam at the energies of interest (i.e. the energies which represent the majority (not the minority) of detected photons from the X-ray source of interest? 2) Have you demonstrated that the device's sensitivity to an unpolarized beam is really negligible and/or quantified the impact of any systematic effects upon actual measurements? We present our answers to these questions backed up by laboratory measurements and give an overview of the mission.

Weisskopf, Martin C.; Baldini, Luca; Bellazini, Ronaldo; Brez, Alessandro; Costa, Enrico; Dissley, Richard; Elsner, Ronald; Fabiani, Sergio; Matt, Giorgio; Minuti, Massimo; Mulieri, Fabio; O'Dell, Steve; Pinchera, Michelle; Ramsey, Brian; Rubini, Alda; Sgro, Carmelo; Soffitta, Paolo; Spandre, Gloria

2013-01-01

416

Compressible fiber optic micro-Fabry-Prot cavity with ultra-high pressure sensitivity.  

PubMed

We propose and demonstrate a pressure sensor based on a micro air bubble at the end facet of a single mode fiber fusion spliced with a silica tube. When immersed into the liquid such as water, the air bubble essentially acts as a Fabry-Prot interferometer cavity. Such a cavity can be compressed by the environmental pressure and the sensitivity obtained is >1000 nm/kPa, at least one order of magnitude higher than that of the diaphragm-based fiber-tip sensors reported so far. The compressible Fabry-Prot interferometer cavity developed is expected to have potential applications in highly sensitive pressure and/or acoustic sensing. PMID:23787598

Wang, Ying; Wang, D N; Wang, Chao; Hu, Tianyi

2013-06-17

417

Test and evaluation of a high-sensitivity assay system for bulk transuranic waste  

SciTech Connect

During the past year, we tested and evaluated the performance of an assay system that accommodates 55-gal drums of transuranic waste at Oak Ridge National Laboratory. This neutron assay system provides a routine assay of fissile transuranic isotopes to the 1-mg sensitivity level with a pulsed active neutron interrogation based on the differential dieaway technique. A highly sensitive passive neutron measurement determines the content of spontaneous fission transuranic isotopes in each drum as well as an upper-bound estimate of the total alpha activity. All components of the combined, pulsed active and passive neutron assay system performed well on a routine basis during the test-and-evaluation period. We performed more than 400 combined passive and active assay measurements of waste drums at Oak Ridge. One-fifth of the initial set of waste drums measured contain less than 100 nCi/g of total transuranic isotopes and thus qualify legally as nontransuranic waste.

Caldwell, J.T.; Close, D.A.; Kuckertz, T.H.; Kunz, W.E.; Pratt, J.C.; Haff, K.W.; Schultz, F.J.

1983-01-01

418

High-sensitivity detection of triacetone triperoxide (TATP) and its precursor acetone  

NASA Astrophysics Data System (ADS)

Triacetone triperoxide (C9H18O6, molecular mass of 222.24 g/mol) (TATP) is a powerful explosive that is easy to synthesize using commonly available household chemicals, acetone, and hydrogen peroxide 1 2. Because of the simplicity of its synthesis, TATP is often the explosive of choice for terrorists, including suicide bombers. For providing safety to the population, early detection of TATP and isolation of such individuals are essential. We report unambiguous, high-sensitivity detection of TATP and its precursor, acetone, using room-temperature quantum cascade laser photoacoustic spectroscopy (QCL-PAS). The available sensitivity is such that TATP, carried on a person (at a nominal body temperature of 37 C), should be detectable at some distance. The combination of demonstrated detection of TATP and acetone should be ideal for screening at airports and other public places for providing increased public safety.

Dunayevskiy, Ilya; Tsekoun, Alexei; Prasanna, Manu; Go, Rowel; Patel, C. Kumar N.

2007-09-01

419

High-sensitivity detection of triacetone triperoxide (TATP) and its precursor acetone.  

PubMed

Triacetone triperoxide (C(9)H(18)O(6), molecular mass of 222.24 g/mol) (TATP) is a powerful explosive that is easy to synthesize using commonly available household chemicals, acetone, and hydrogen peroxide 1 2. Because of the simplicity of its synthesis, TATP is often the explosive of choice for terrorists, including suicide bombers. For providing safety to the population, early detection of TATP and isolation of such individuals are essential. We report unambiguous, high-sensitivity detection of TATP and its precursor, acetone, using room-temperature quantum cascade laser photoacoustic spectroscopy (QCL-PAS). The available sensitivity is such that TATP, carried on a person (at a nominal body temperature of 37 degrees C), should be detectable at some distance. The combination of demonstrated detection of TATP and acetone should be ideal for screening at airports and other public places for providing increased public safety. PMID:17805380

Dunayevskiy, Ilya; Tsekoun, Alexei; Prasanna, Manu; Go, Rowel; Patel, C Kumar N

2007-09-01

420

Highly sensitive carbon nanotube-embedding gas sensors operating at atmospheric pressure  

NASA Astrophysics Data System (ADS)

Highly sensitive palladium (Pd) decorated carbon nanotube (CNT) embedding gas sensors working at atmospheric pressure were fabricated. Two types of gas sensors of bare CNTs and Pd nanoparticle decorated CNTs were synthesized by dielectrophoresis. The CNT-containing solution was dropped onto the patterned-platinum electrodes with ac bias. The CNT-embedding sensors sensitively detected 100 ppb level of NO2 in an atmospheric pressure condition. The Pd decoration on CNTs forming the depletion region was found to be an effective way to enhance the sensor response by the control of carrier mobility and density. Raman spectroscopy revealed a low defect ratio of D/G- by heat treatment at 450 C. Moreover, it was investigated that there exists an optimum temperature to enhance the sensor response.

Yun, Ju-Hyung; Kim, Joondong; Park, Yun Chang; Song, Jin-Won; Shin, Dong-Hun; Han, Chang-Soo

2009-02-01