Sample records for highly sensitive uplc-ms

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

    PubMed Central

    2012-01-01

    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

  2. Magnetic solid phase extraction coupled with in situ derivatization for the highly sensitive determination of acidic phytohormones in rice leaves by UPLC-MS/MS.

    PubMed

    Liu, Jiu-Feng; Ding, Jun; Yuan, Bi-Feng; Feng, Yu-Qi

    2014-11-01

    A simple, rapid and sensitive method based on magnetic solid phase extraction (MSPE) coupled with in situ derivatization (ISD) was developed for the determination of endogenous acidic phytohormones in rice leaves by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) analysis. With this method, acidic phytohormones were extracted onto the surface of a TiO2/magnetic hollow mesoporous silica sphere (MHMSS) through hydrophilic interaction, and then in situ derivatization was performed by the subsequent addition of 3-bromoactonyltrimethylammonium bromide (BTA). Thus, the process integrated extraction, purification, and derivatization into one step. Additionally, the permanent positively charged moiety from BTA significantly improved the ionization efficiencies of the acidic phytohormones. Several parameters affecting the efficiencies of the extraction, derivatization, and desorption were evaluated. The signal intensities of acidic phytohormones increased by 2 to 481 fold after treatment with MSPE-ISD. Under the optimized conditions, several endogenous acidic phytohormones, including GA4, GA9, GA20, JA, IAA, and ABA, were identified and quantified in rice leaves by the MSPE-ISD method. The limits of detection (LODs) were in the range of 1.03-91.21 pg mL(-1). The relative recoveries ranged from 71.6-112.8%, with the intra- and interday relative standard deviations (RSDs) being less than 14.9% and 16.2%, respectively. Taken together, the proposed method provides a novel approach of combining magnetic solid phase extraction and in situ derivatization for the highly sensitive determination of endogenous acidic phytohormones. PMID:25148576

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

    PubMed

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

    2014-08-01

    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

  4. Sensitive UPLC-MS-MS assay for 21 benzodiazepine drugs and metabolites, zolpidem and zopiclone in serum or plasma.

    PubMed

    Marin, Stephanie J; Roberts, Mark; Wood, Michelle; McMillin, Gwendolyn A

    2012-09-01

    This paper reports an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method to quantitate 21 benzodiazepines, zolpidem and zopiclone in serum and plasma. After liquid-liquid extraction, an Acquity UPLC with a TQ Detector and BEH C18 column was used (Waters, Milford, MA). The injection-to-injection run time was 7.5 min. Forty-eight authentic serum and plasma patient specimens were analyzed and results compared to those obtained using a previously published method. Average r(2) values for linearity (1 to 1,000 ng/mL over five days) were all above 0.995, except ?-hydroxytriazolam (0.993). Intra-day and inter-day relative standard deviation values were within ± 15% and the percent deviation from the expected concentrations were within ± 11%. Recovery ranged from 62 to 89%. Matrix effects ranged from -28% to +6%. The limits of detection were 1 ng/mL, except for lorazepam, nordiazepam, oxazepam and temazepam (5 ng/mL). Ion ratios were ± 15% for all analytes. For authentic patient specimens (n = 48, 76 positive results), there was excellent correlation between the UPLC-MS-MS results and the previous method. The best least-squares fit had an equation of y = 1.0708x + 1.6521, r(2) = 0.9822. This UPLC-MS-MS method is suitable for the quantification of benzodiazepines and hypnotics in serum and plasma, and offers fast, reliable and sensitive results. PMID:22833647

  5. Development of a rapid and sensitive UPLC-MS/MS assay for the determination of TM-2 in beagle dog plasma and its application to a pharmacokinetic study.

    PubMed

    Lin, Hongli; Zhao, Yunli; Men, Lei; Yang, Mingjing; Liu, Hui; Shao, Yanjie; Wang, Pei; Tang, Xing; Yu, Zhiguo

    2015-01-01

    A simple and sensitive method based on ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) has been developed for the determination of TM-2, which was a novel semi-synthetic taxane derivative in beagle dog plasma. Cabazitaxel was chosen as internal standard. Following extraction by methyl tert-butyl ether, the chromatographic separation was achieved on a Thermo Syncronis C18 column (50?×?2.1 mm, 1.7 µm) by gradient elution within a runtime of 3.5 min. The mobile phase consisted of (A) acetonitrile and (B) 2 mmol/L ammonium acetate in water. The detection was accomplished using positive ion electrospray ionization in multiple reaction monitoring mode. The MS/MS ion transitions were monitored at m/z 812.39???551.35 for TM-2 and 836.36???555.26 for IS, respectively. The method was linear for TM-2 (r?=?0.9924) ranging from 2.5 to 1000 ng/mL. The intra-day and inter-day precisions (relative standard deviation) were within 8.0 and 17.6%, respectively, and the accuracy (relative error) was less than 2.3%. The extraction recovery ranged from 83.1 to 97.1%. The reliable method was successfully applied to a pharmacokinetic study of TM-2 in beagle dogs after intravenous drip with different doses of 0.6, 1.2, and 2.4 mg/kg, respectively. PMID:24828525

  6. A UPLC-MS/MS application for profiling of intermediary energy metabolites in microdialysis samples--a method for high-throughput.

    PubMed

    Birkler, Rune Isak Dupont; Støttrup, Nicolaj Brejnholt; Hermannson, Sigurd; Nielsen, Torsten Toftegaard; Gregersen, Niels; Bøtker, Hans Erik; Andreasen, Mette Findal; Johannsen, Mogens

    2010-12-01

    Research within the field of metabolite profiling has already illuminated our understanding of a variety of physiological and pathological processes. Microdialysis has added further refinement to previous models and has allowed the testing of new hypotheses. In the present study, a new ultra-performance liquid chromatography/electrospray-tandem mass spectrometry (UPLC-ESI-MS/MS) method for the simultaneous detection and quantification of intermediary energy metabolites in microdialysates was developed. The targeted metabolites were mainly from the citric acid cycle in combination with pyruvic acid, lactic acid, and the ATP (adenosine triphosphate) hydrolysis product adenosine along with metabolites of adenosine. This method was successfully applied to analyze the microdialysates obtained from an experimental animal study giving insight into the hitherto unknown concentration of many interstitial energy metabolites, such as succinic acid and malic acid. With a total cycle time of 3 min, injection to injection, this method permits analysis of a much larger number of samples in comparison with conventional high performance liquid chromatography/tandem mass spectrometry HPLC-MS/MS strategies. With this novel combination where microdialysis and high sensitivity UPLC-MS/MS technique is combined within cardiologic research, new insights into the intermediary energy metabolism during ischemia-reperfusion is now feasible. PMID:20634014

  7. A validated UPLC-MS/MS assay using negative ionization mode for high-throughput determination of pomalidomide in rat plasma.

    PubMed

    Iqbal, Muzaffar; Ezzeldin, Essam; Al-Rashood, Khalid A; Shakeel, Faiyaz

    2015-03-01

    In this study, a sensitive UPLC-MS/MS assay was developed and validated for high-throughput determination of pomalidomide in rat plasma using celecoxib as an internal standard (IS). Liquid liquid extraction using dichloromethane was employed to extract pomalidomide and IS from 200?L of plasma. Chromatographic separation was carried on Acquity BEH™ C18 column (50mm×2.1mm, 1.7?m) using an isocratic mobile phase of acetonitrile: 10mM ammonium acetate (80:20, v/v), at a flow rate of 0.250mL/min. Both pomalidomide and IS were eluted at 0.66±0.03 and 0.80±0.03min, respectively, with a total run time of 1.5min only. A triple quadruple tandem mass spectrometer using electrospray ionization in negative mode was employed for analyte detection. The precursor to product ion transitions of m/z 272.01?160.89 for pomalidomide and m/z 380.08?316.01 for IS were used to quantify them respectively, multiple reaction monitoring mode. The developed method was validated according to regulatory guideline for bioanalytical method validation. The linearity in plasma sample was achieved in the concentration range of 0.47-400ng/mL (r(2)?0.997). The intra and inter-day precision values were ?11.1% (RSD, %) whereas accuracy values ranged from -6.8 to 8.5% (RE, %). In addition, other validation results were within the acceptance criteria and the method was successfully applied in a pharmacokinetic study of pomalidomide in rats. PMID:25621435

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

    PubMed

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

    2014-06-01

    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?mm×50?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

  9. Determination of opiates and cocaine in urine by high pH mobile phase reversed phase UPLC-MS/MS.

    PubMed

    Berg, Thomas; Lundanes, Elsa; Christophersen, Asbjørg S; Strand, Dag Helge

    2009-02-01

    A fast and selective ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the determination of opiates (morphine, codeine, 6-monoacetylmorphine (6-MAM), pholcodine, oxycodone, ethylmorphine), cocaine and benzoylecgonine in urine has been developed and validated. Sample preparation was performed by solid phase extraction (SPE) on a mixed mode cation exchange (MCX) cartridge. For optimized chromatographic performance with repeatable retention times, narrow and symmetrical peaks, and focusing of all analytes at the column inlet at gradient start, a basic mobile phase consisting of 5mM ammonium bicarbonate, pH 10.2, and methanol (MeOH) was chosen. Positive electrospray ionization (ESI(+)) MS/MS detection was performed with a minimum of two multiple reaction monitoring (MRM) transitions for each analyte. Deuterium labelled-internal standards were used for six of the analytes. Between-assay retention time repeatabilities (n=10 series, 225 injections in total) had relative standard deviation (RSD) values within 0.1-0.6%. Limit of detection (LOD) and limit of quantification (LOQ) values were in the range 0.003-0.05 microM (0.001-0.02 microg/mL) and 0.01-0.16 microM (0.003-0.06 microg/mL), respectively. The RSD values of the between-assay repeatabilities of concentrations were

  10. A selective and sensitive UPLC-MS/MS approach for trace level quantification of four potential genotoxic impurities in zolmitriptan drug substance.

    PubMed

    Vijaya Bhaskar Reddy, A; Venugopal, N; Madhavi, G; Gangadhara Reddy, K; Madhavi, V

    2013-10-01

    The pivotal task of pharmaceutical industry is to separate and quantify the potential genotoxic impurities (PGIs) rising from the process of drug production. For trace level quantification of these PGIs we need to develop sensitive and selective analytical methods. APP, NPA, NPP and MNA have been highlighted as PGIs in zolmitriptan. A sensitive and selective UPLC-MS/MS method has developed for identification and quantification of four PGIs viz. APP, NPA, NPP and MNA in zolmitriptan. The method utilizes Hypersil BDS C8 column (50 mm × 4.6 mm, 3.0 ?m) with electrospray ionization in selected ion recording (SIR) mode for quantitation of four PGIs. The method was validated as per International Conference on Harmonization (ICH) guidelines and is able to quantitate APP at 0.1 ppm and NPA, NPP and MNA at 0.15 ppm with respect to 5.0mg/mL of zolmitriptan. The proposed method is specific, linear, accurate and precise. The method is linear in the range of 0.1-2.0 ppm for APP and 0.15-2.0 ppm for NPA, NPP and MNA, which matches the range of LOQ-200% of estimated permitted level (1.0 ppm). The correlation coefficient obtained was >0.999 in each case. The impurities were not present in the studied three pure and formulation batches of zolmitriptan. The accuracy of the method was ranged between 98.1 and 102.8% for four PGIs. This method is a good quality control tool for quantitation of four APP, NPA, NPP and MNA PGIs at very low levels in zolmitriptan. PMID:23816589

  11. 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

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

    2015-01-01

    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 (100 mm × 4.6mm, 2.4 ?m) at a flow rate of 0.7 ml/min using 0.2% ammonium acetate solution (containing 0.1% formic acid) and methanol as mobile phase. The total run time was 4 min. 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 1 ng/ml for rat plasma and 0.25 ng/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

  12. Simultaneous determination of genistein and its four phase II metabolites in blood by a sensitive and robust UPLC-MS/MS method: application to an oral bioavailability study of genistein in mice

    PubMed Central

    Yang, Zhen; Zhu, Wei; Gao, Song; Xu, Haiyan; Wu, Baojian; Kulkarni, Kaustubh; Singh, Rashim; Tang, Lan; Hu, Ming

    2012-01-01

    The purpose of this research was to develop a sensitive and reproducible UPLC-MS/MS method to simultaneously quantify genistein, genistein-7-O-glucuronide (G-7-G), genistein-4’-O-glucuronide (G-4’-G), genistein-4’-O-sulfate (G-4’-S) and genistein-7-Osulfate (G-7-S) in mouse blood samples. After the method was fully validated over a wide linear range, it was applied to quantify the levels of genistein and its metabolites in a mouse bioavailability study. The linear response range were 19.5–10,000 nM for genistein, 12.5–3,200 nM for G-7-G, 20–1280 nM for G-4’-G, 1.95–2,000 nM for G-4’-S, and 1.56–3,200 nM for G-7-S, respectively. The lower limit of quantification (LLOQ) was 4.88, 6.25, 5, 0.98 and 0.78 nM for genistein, G-7-G, G-4’-G, G-4’-S and G-7-S, respectively. Only 20 µl mouse blood sample from i.v. and p.o. administration were needed for analysis because of the high sensitivity of the method. The intra- and inter-day variance is less than 15% and accuracy is within 85–115%. The analysis was finished within 4.5 min. The applicability of this assay was demonstrated and successfully applied for bioavailability study in FVB mouse after i.v. and p.o. administration of 20 mg/kg of genistein, and its oral bioavailability was ~24%. PMID:20378296

  13. Simultaneous Determination of Fluoroquinolones, Tetracyclines and Sulfonamides in Chicken Muscle by UPLC–MS–MS

    Microsoft Academic Search

    Jianzhong Shen; Liming Guo; Fei Xu; Qinxiong Rao; Xi Xia; Xiaowei Li; Shuangyang Ding

    2010-01-01

    A rapid and sensitive analytical method for the simultaneous determination of four fluoroquinolones, four tetracyclines and\\u000a six sulfonamides in chicken muscle using ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC–MS–MS)\\u000a has been developed and validated. Samples were extracted with McIlvaine buffer-acetonitrile, defatted with n-hexane, and analyzed by UPLC–MS–MS. Solvent delay technique was applied in the analysis to remove the

  14. SIMPLE AND RAPID QUANTITATION OF 21 BILE ACIDS IN RAT SERUM AND LIVER BY UPLC-MS-MS: EFFECT OF HIGH FAT DIET ON GLYCINE CONJUGATES OF RAT BILE ACIDS

    PubMed Central

    SUZUKI, YUDAI; KANEKO, RINA; NOMURA, MINA; NAITO, HISAO; KITAMORI, KAZUYA; NAKAJIMA, TAMIE; OGAWA, TADASHI; HATTORI, HIDEKI; SENO, HIROSHI; ISHII, AKIRA

    2013-01-01

    ABSTRACT In this report, we present a simple and rapid method for analysis of 21 kinds of bile acids and the conjugates in rat serum and liver samples by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) in the negative ionization mode, using cholic-2, 2, 4, 4-d4 acid as internal standard. After liquid-liguid extraction from serum and liver samples, specimens were analyzed by UPLC equipped with an Acquity TQD tandem quadrupole mass spectrometer. All of the 21 bile acids were sufficiently separated within 5 min. For most bile acids, calibration curves showed good linearities in the range of 0.25 to 5000 ng/mL for serum samples, 2.5 ng/g to 50 ?g/g for liver samples. The limits of detection (LOD) were estimated to be less than 0.25 to 7.5 ng/mL in serum, less than 2.5 to 10 ng/g in liver samples. The present method was validated with respect to repeatability; the coefficient of variation (CV) values were less than 26.7% in the serum and 25.9% in the liver. In the animal study, we compared 21 bile acids in the serum and liver samples of the stroke-prone spontaneously hypertensive (SHRSP) rats fed with control (SP) diet or high-fat and high-cholesterol-containing (HFC) diet. By feeding with HFC diet, the glycine conjugates of some bile acids significantly increased and the taurine conjugate of ulsodeoxicolate (TUDC) decreased in serum and liver samples. Our results suggest that the change of bile acid profiles could be applied for the diagnosis of non-alcoholic fatty liver disease (NAFLD). PMID:23544269

  15. Profiling counterfeit Cialis, Viagra and analogs by UPLC-MS.

    PubMed

    Ortiz, Rafael S; Mariotti, Kristiane de Cássia; Holzschuh, Maribete H; Romão, Wanderson; Limberger, Renata P; Mayorga, Paulo

    2013-06-10

    In this work, the chemical profile of 43 commercial samples of tablets for male erectile dysfunction (Viagra, Cialis, Lazar, Libiden, Maxfil, Plenovit, Potent 75, Rigix, Vimax, Pramil 75 and Pramil) and 65 counterfeit samples (Viagra and Cialis) were obtained from UPLC-MS data. Methanol extracts of crushed tablets were investigated by ultra performance liquid chromatography (UPLC) with diode array detection (DAD) coupled with eletrospray ionization in the positive ion mode (ESI(+)) quadrupole time-of-flight (Q-Tof) mass spectrometry (MS). A validated method was employed for the simultaneous determination of sildenafil citrate (SLD) and tadalafil (TAD). The ultra-chromatograms obtained with method provide high resolution of MS, and are a quick (less to 1.5 min) and reliable tool in the distinction between authentic and counterfeit tablets. It was observed in most cases the presence of other active pharmaceutical ingredients (APIs) than specified on the package (TAD and SLD). Additionally, high concentrations of TAD and SLD were detected in counterfeit samples when compare with observed values for a typical commercial product. Chemometric methods were employed and the samples were grouped in five groups as function of API content. PMID:23683904

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

    PubMed

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

    2015-02-15

    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

  17. Assessment of Oxidative Damage to Proteins and DNA in Urine of Newborn Infants by a Validated UPLC-MS/MS Approach

    PubMed Central

    Kuligowski, Julia; Torres-Cuevas, Isabel; Quintás, Guillermo; Rook, Denise; van Goudoever, Johannes B.; Cubells, Elena; Asensi, Miguel; Lliso, Isabel; Nuñez, Antonio; Vento, Máximo; Escobar, Javier

    2014-01-01

    The assessment of oxidative stress is highly relevant in clinical Perinatology as it is associated to adverse outcomes in newborn infants. This study summarizes results from the validation of an Ultra Performance Liquid Chromatography–tandem Mass Spectrometry (UPLC-MS/MS) method for the simultaneous quantification of the urinary concentrations of a set of endogenous biomarkers, capable to provide a valid snapshot of the oxidative stress status applicable in human clinical trials, especially in the field of Perinatology. The set of analytes included are phenylalanine (Phe), para-tyrosine (p-Tyr), ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-NO2-tyrosine (3NO2-Tyr), 3-Cl-tyrosine (3Cl-Tyr), 2?-deoxyguanosine (2dG) and 8-hydroxy-2?-deoxyguanosine (8OHdG). Following the FDA-based guidelines, appropriate levels of accuracy and precision, as well as adequate levels of sensitivity with limits of detection (LODs) in the low nanomolar (nmol/L) range were confirmed after method validation. The validity of the proposed UPLC-MS/MS method was assessed by analysing urine samples from a clinical trial in extremely low birth weight (ELBW) infants randomized to be resuscitated with two different initial inspiratory fractions of oxygen. PMID:24695409

  18. Determination of buprenorphine, fentanyl and LSD in whole blood by UPLC-MS-MS.

    PubMed

    Berg, Thomas; Jørgenrud, Benedicte; Strand, Dag Helge

    2013-04-01

    A sensitive ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) method has been developed and validated for the quantification of buprenorphine, fentanyl and lysergic acid diethylamide (LSD) in whole blood. Sample preparation was performed by liquid-liquid extraction (LLE) with methyl tert-butyl ether. UPLC-MS-MS analysis was performed with a mobile phase consisting of ammonium formate (pH 10.2) and methanol. Positive electrospray ionization MS-MS detection was performed with two multiple reaction monitoring transitions for each of the analytes and the deuterium labeled internal standards. Limit of detection values of buprenorphine, fentanyl and LSD were 0.28, 0.044 and 0.0097 ng/mL and limit of quantification values were 0.94, 0.14 and 0.036 ng/mL, respectively. Most phospholipids were removed during LLE. No or only minor matrix effects were observed. The method has been routinely used at the Norwegian Institute of Public Health since September 2011 for qualitative and quantitative detections of buprenorphine, fentanyl and/or LSD in more than 400 whole blood samples with two replicates per sample. PMID:23423312

  19. Simultaneous determination of 38 veterinary antibiotic residues in raw milk by UPLC-MS/MS.

    PubMed

    Han, R W; Zheng, N; Yu, Z N; Wang, J; Xu, X M; Qu, X Y; Li, S L; Zhang, Y D; Wang, J Q

    2015-08-15

    A selective and rapid method has been developed to determine, simultaneously, 38 veterinary antibiotic residues in raw milk by ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). One milliliter of raw milk was diluted with 0.5mL water and 3mL acetonitrile, then purified using an Oasis HLB cartridge. The eluates were evaporated by nitrogen drying and then reconstituted to 4mL with water/acetonitrile (8:1) before being injected into the UPLC-MS/MS system. The results indicated recoveries of 68-118% for 14 ?-lactams, 79-118% for eight quinolones, 71-106% for eight sulfonamides, 76-116% for four tetracyclines, 78-106% for three macrolides, and 88-103% for one lincosamides, with coefficients of variation less than 15% for intraday and interday precisions. The limit of quantification for all antibiotics was 0.03-10?gkg(-1). This methodology was then applied to field-collected real raw milk samples and trace levels of four antibiotics were detected. PMID:25794729

  20. Screening and quantitative determination of drugs of abuse in diluted urine by UPLC-MS/MS.

    PubMed

    Hegstad, Solfrid; Hermansson, Sigurd; Betnér, Ingvar; Spigset, Olav; Falch, Berit Margrethe Hasle

    2014-02-01

    The purpose of this work was to develop and evaluate a fast, robust and specific UPLC-MS/MS screening platform for the determination and quantification of a variety of commonly used drugs of abuse in urine, i.e. a high-throughput quantitative analysis. Substances in the drug classes opioids, central nervous system stimulants and benzodiazepines and related agents were included in addition to cannabis and pregabalin, a total of 35 different analytes. Based on the concentrations and the physico-chemical properties of the substances, three UPLC-MS/MS methods were developed in parallel. Prior to analysis, sample preparation consisted of two different simple dilutions with 60 and 100 ?L urine, respectively, using a Tecan Freedom Evo pipetting robot platform. A Waters Xevo TQ-S tandem quadrupole mass spectrometer coupled to a Waters I-class UPLC was used for quantitative analysis of one quantitative and one qualifying MRM transition for each analyte, except for tramadol for which the metabolite O-desmethyl-tramadol was included in the MRM method to confirm tramadol identity. Deuterated analogs were included as internal standards. The between-assay relative standard deviations varied from 2% to 11% and the limits of quantification were in the range 1-200 ng/mL for the various analytes. After development and initial testing, the method has been successfully implemented and routinely used at our hospital for quantitative screening of drugs of abuse in more than 35,000 urinary samples. PMID:24413020

  1. An UPLC-MS/MS method for quantitative profiling of bile acids in sea lamprey plasma and tissues.

    PubMed

    Wang, Huiyong; Yeh, Chu-Yin; Li, Ke; Chung-Davidson, Yu-Wen; Li, Weiming

    2015-02-01

    Bile acids (BAs) have recently gained more attention because of their diverse roles from digestion to signaling. Simultaneous analyses of various BAs in biological samples are challenging due to their structural similarity, relatively low concentrations, and the presence of isomeric forms. In this study, we report a simple and sensitive UPLC-MS/MS method for simultaneous quantifications of 13 BAs including four unique sea lamprey BAs in sea lamprey plasma, liver, intestine, and gills. A straightforward protein precipitation (PPT) method was used to extract BAs from the biological samples. Separation of all target analytes was achieved on a reverse-phase UPLC column in 15min, and detection was carried out on MS/MS with ESI in the negative ionization mode. This method was validated regarding its linearity, limits of detection (LOD), recovery, matrix effect, reproducibility, accuracy and precision. Significant improvements compared to previous LC-MS/MS methods were observed as a result of the application of UPLC and extensive optimization of experimental conditions. The method showed excellent linearity with high regression coefficients (>0.99) over a range of 0.5-1000ng/mL and LODs ranged from 0.009 to 0.11ng/mL. The applications of the developed method demonstrated that it simultaneously determined all target BAs in different biological sample matrices with excellent sensitivity, selectivity and reproducibility. PMID:25589257

  2. A Fast One Step Extraction and UPLC-MS/MS Analysis for E2/D2 Series Prostaglandins and Isoprostanes

    PubMed Central

    Brose, Stephen A.; Baker, Andrew G.; Golovko, Mikhail Y.

    2013-01-01

    Prostaglandins (PG) and isoprostanes (iso-PG) may be derived through cyclooxygenase or free radical pathways and are important signaling molecules that are also robust biomarkers of oxidative stress. Their quantification is important for understanding many biological processes where PG, iso-PG, or oxidative stress are involved. One of the common methods for PG and iso-PG quantifications is LC-MS/MS that allows a highly selective, sensitive, simultaneous analysis for prostanoids without derivatization. However, the currently used LC-MS/MS methods require a multi-step extraction and a long (within an hour) LC separation to achieve simultaneous separation and analysis of the major iso-PG. The developed and validated for brain tissue analysis one-step extraction protocol and UPLC-MS/MS method significantly increases the recovery of the PG extraction up to 95%, and allows for a much faster (within 4 min) major iso-PGE2 and -PGD2 separation with 5 times narrower chromatographic peaks as compared to previously used methods. In addition, it decreases the time and cost of analysis due to one-step extraction approach performed in disposable centrifuge tubes. All together, this significantly increases the sensitivity, and the time and cost efficiency of the PG and iso-PG analysis. PMID:23400687

  3. UPLC-MS/MS measurement of S-nitrosoglutathione (GSNO) in human plasma solves the S-nitrosothiol concentration enigma.

    PubMed

    Tsikas, Dimitrios; Schmidt, Mario; Böhmer, Anke; Zoerner, Alexander A; Gutzki, Frank-Mathias; Jordan, Jens

    2013-05-15

    We developed and validated a fast UPLC-MS/MS method with positive electrospray ionization (ESI+) for the quantitative determination of S-nitrosoglutathione (GSNO) in human plasma. We used a published protocol for the inactivation of plasma ?-glutamyltransferase (?GT) activity by using the ?GT transition inhibitor serine/borate and the chelator EDTA for the stabilization of GSNO, and N-ethylmaleimide (NEM) to block SH groups and to avoid S-transnitrosylation reactions which may diminish GSNO concentration. S-[(15)N]Nitrosoglutathione (GS(15)NO) served as internal standard. Fresh blood was treated with NEM/serine/borate/EDTA, plasma spiked with GS(15)NO (50nM) was ultrafiltered (cut-off 10kDa) and 10?L aliquots of the ultrafiltrate were analyzed by UPLC-MS/MS. Five HILIC columns and an Acquity UPLC BH amide column were tested. The mobile phase was acetonitrile-water (70:30, v/v), contained 20mM ammonium formate, had a pH value of 7, and was pumped isocratically (0.5mL/min). The Nucleoshell column allowed better LC performance and higher MS sensitivity. The retention time of GSNO was about 1.1min. Quantification was performed by selected-reaction monitoring the mass transition m/z 337 ([M+H](+))?m/z 307 ([M+H(14)NO](+)) for GSNO (i.e., GS(14)NO) and m/z 338 ([M+H](+))?m/z 307 ([M+H(15)NO](+)) for GS(15)NO. NEM/serine/borate/EDTA was found to stabilize GSNO in human plasma. The method was validated in human plasma (range, 0-300nM) using 50nM GS(15)NO. Accuracy and precision were in generally acceptable ranges. A considerable matrix effect was observed, which was however outweighed by the internal standard GS(15)NO. In freshly prepared plasma from heparinized blood donated by 10 healthy subjects, no endogenous GSNO was determined above 2.8nM, the limit of quantitation (LOQ) of the method. This study challenges previously reported GSNO plasma concentrations being far above the present method LOQ value and predicts that the concentration of low-molecular-mass and high-molecular-mass S-nitrosothiols are in the upper pM- and lower nM-range, respectively. PMID:23453822

  4. From cells to muropeptide structures in 24?h: Peptidoglycan mapping by UPLC-MS

    PubMed Central

    Kühner, Daniel; Stahl, Mark; Demircioglu, Dogan D.; Bertsche, Ute

    2014-01-01

    Peptidoglycan (PGN) is ubiquitous in nearly all bacterial species. The PGN sacculus protects the cells against their own internal turgor making PGN one of the most important targets for antibacterial treatment. Within the last sixty years PGN composition has been intensively studied by various methods. The breakthrough was the application of HPLC technology on the analysis of muropeptides. However, preparation of pure PGN relied on a very time consuming method of about one week. We established a purification protocol for both Gram-positive and Gram-negative bacteria which can be completely performed in plastic reaction tubes yielding pure muropeptides within 24?hours. The muropeptides can be analyzed by UPLC-MS, allowing their immediate determination. This new rapid method provides the feasibility to screen PGN composition even in high throughput, making it a highly useful tool for basic research as well as for the pharmaceutical industry. PMID:25510564

  5. Quantitation of leukotriene B(4) in human sputum as a biomarker using UPLC-MS/MS.

    PubMed

    Jian, Wenying; Edom, Richard W; Xue, Xiaohua; Huang, Mike-Qingtao; Fourie, Anne; Weng, Naidong

    2013-08-01

    Leukotriene B4 (LTB4) is a potent mediator of inflammation and has been recognized as an important target for therapeutic intervention for treatment of diseases such as asthma. In the current work, a highly selective and sensitive UPLC-MS/MS assay was developed for quantitation of LTB4 in human sputum as a biomarker for LTB4 biosynthesis inhibition. A fit-for-purpose strategy for method development, assay qualification, and study support was adopted for this biomarker project. A surrogate matrix (protein buffer) was used for preparation of calibration samples and certain levels of quality control (QC) samples to avoid interference from endogenous analyte, while the low QC was prepared in authentic matrix, human sputum. The analytical methodology utilized a liquid-liquid extraction procedure in 96-well plate format. Chromatographic separation was achieved with a reversed-phase ultra high pressure liquid chromatography (UPLC) column using gradient elution, and the run time was 4.5min per sample. The lower limit of quantitation (LLOQ) was 0.2ng/mL, and the calibration curve range was 0.2-20ng/mL. Acceptable accuracy, precision, linearity, specificity, recovery, and matrix effect was obtained. Bench-top stability (6h), freeze-thaw stability (3 cycles at -20°C), and autosampler stability (97h at ambient temperature) all met acceptance criteria. Frozen long-term stability for 166 days at -20°C in sputum did not meet acceptance criteria by showing only ?75% of nominal concentration and the information was taken into consideration for study support. Two important observations in the current work were: (1) LTB4 was unstable in sputum in the presence of liquification reagent dithiothreitol (DTT). Therefore, a non-DTT treatment method for sputum processing was developed and applied to the bioanalytical assay and clinical study support; and (2) chromatographic separation of LTB4 from its three non-enzymatically derived isomers, i.e. 6-trans-LTB4, 12-epi-LTB4, and 6-trans-12-epi-LTB4, was achieved. This assay was successfully applied to a Phase II clinical study for proof-of-concept of a LTA4 hydrolase inhibitor for treatment of asthma. PMID:23831697

  6. A rapid and sensitive UPLC-MS/MS method for the simultaneous quantification of serum androsterone glucuronide, etiocholanolone glucuronide, and androstan-3?, 17? diol 17-glucuronide in postmenopausal women.

    PubMed

    Ke, Yuyong; Gonthier, Renaud; Isabelle, Maxim; Bertin, Jonathan; Simard, Jean-Nicolas; Dury, Alain Y; Labrie, Fernand

    2015-05-01

    Quantification of steroidal glucuronide conjugates by the indirect methods of immunoassay and GC-MS/MS may underestimate some conjugates since hydrolysis is needed in sample processing. In the present work, a sensitive and rapid liquid chromatography-tandem mass spectrometry (LC-MS/MS) method has been developed and validated for the simultaneous direct quantification of androsterone glucuronide, etiocholanolone glucuronide, and androstan-3?, 17? diol 17-glucuronide in postmenopausal women's serum. The quantification limits are 0.1ng/mL for 3?-diol-17G and 4ng/mL for both ADT-G and Etio-G, respectively, with an extraction from 200?L serum while the total run time is less than 6min for all three glucuronides. In this method, solid phase extraction is used for sample preparation. The assay has been validated in compliance with EndoCeutics SOPs and FDA guidelines for bioanalytical method development and validation. The recovery of glucuronides in stripped serum is consistent with that in unstripped serum, where the average difference in stripped and unstripped is less than 10%. A linear regression model fits well the standard curves of all three compounds with R?0.99 where the weighting factor is 1/X. Interday accuracy and CV for all levels of QCs are within the range of 15% in both stripped and unstripped serum while all calibration curves are within the range of 6% except for LLOQs, which are within the range of 9%. Other parameters have also been assessed such as selectivity, matrix, lipemic and hemolysis effects as well as stabilities in solution and matrix. Incurred sample reanalysis has been performed with a result of over 93% within 20% of the original values. This reliable, sensitive and fast method is ready for large-scale clinical sample assays. PMID:25701608

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

    PubMed Central

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

    2014-01-01

    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

  8. A method for the direct injection and analysis of small volume human blood spots and plasma extracts containing high concentrations of organic solvents using revered-phase 2D UPLC/MS.

    PubMed

    Rainville, Paul D; Simeone, Jennifer L; Root, Dan S; Mallet, Claude R; Wilson, Ian D; Plumb, Robert S

    2015-03-01

    The emergence of micro sampling techniques holds great potential to improve pharmacokinetic data quality, reduce animal usage, and save costs in safety assessment studies. The analysis of these samples presents new challenges for bioanalytical scientists, both in terms of sample processing and analytical sensitivity. The use of two dimensional LC/MS with, at-column-dilution for the direct analysis of highly organic extracts prepared from biological fluids such as dried blood spots and plasma is demonstrated. This technique negated the need to dry down and reconstitute, or dilute samples with water/aqueous buffer solutions, prior to injection onto a reversed-phase LC system. A mixture of model drugs, including bromhexine, triprolidine, enrofloxacin, and procaine were used to test the feasibility of the method. Finally an LC/MS assay for the probe pharmaceutical rosuvastatin was developed from dried blood spots and protein-precipitated plasma. The assays showed acceptable recovery, accuracy and precision according to US FDA guidelines. The resulting analytical method showed an increase in assay sensitivity of up to forty fold as compared to conventional methods by maximizing the amount loaded onto the system and the MS response for the probe pharmaceutical rosuvastatin from small volume samples. PMID:25655051

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

    PubMed Central

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

    2014-01-01

    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 µg kg?1 and 0.96 µg 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 (µg kg?1) of cephapirin in dairy cow feces, and cephapirin in urine was detected at very high concentrations (133 to 480 µg 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

  10. A rapid SPE-based analytical method for UPLC/MS/MS determination of aminoglycoside antibiotic residues in bovine milk, muscle, and kidney.

    PubMed

    Young, Michael S; van Tran, Kim; Goh, Evelyn; Shia, Jeremy C

    2014-01-01

    An SPE-based cleanup protocol was developed for ultra-performance LC (UPLC)/MS/MS determination of residues of the common aminoglycoside antibiotics streptomycin, dihydrostreptomycin, neomycin, and gentamicin in bovine milk, kidney, and muscle. Recoveries for all compounds except neomycin ranged from 80 to 104% for all matrixes studied; recoveries for neomycin ranged from 71 to 84%. Intraday and interday precision data were under 15% for all sample matrixes. Compared with other recently reported cleanup methods, less sample is required, the use of potentially dangerous reagents is minimized, and fewer manipulations are required by the analyst. A high throughput 96-well plate format was used for SPE cleanup and UPLC/MS analysis. PMID:25632452

  11. Ultra-performance liquid chromatography tandem mass-spectrometry (uplc-ms/ms) for the rapid, simultaneous analysis of thiamin, riboflavin, flavin adenine dinucleotide, nicotinamide and pyridoxal in human milk

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A novel, rapid and sensitive Ultra Performance Liquid-Chromatography tandem Mass-Spectrometry (UPLC-MS/MS) method for the simultaneous determination of several B-vitamins in human milk was developed. Resolution by retention time or multiple reaction monitoring (MRM) for thiamin, riboflavin, flavin a...

  12. Simultaneous UPLC-MS/MS analysis of native catechins and procyanidins and their microbial metabolites in intestinal contents and tissues of male Wistar Furth inbred rats.

    PubMed

    Goodrich, Katheryn M; Neilson, Andrew P

    2014-05-01

    Procyanidins have been extensively investigated for their potential health protective activities. However, the potential bioactivities of procyanidins are limited by their poor bioavailability. The majority of the ingested dose remains unabsorbed and reaches the colon where extensive microbial metabolism occurs. Most existing analytical methods measure either native compounds (catechins and procyanidins), or their microbial metabolites. The objectives of this study were to develop a high-throughput extraction and UPLC-MS/MS method for simultaneous measurement of both native procyanidins and their metabolites, facilitating high-throughput analysis of native and metabolite profiles in various regions of the colon. The present UPLC-MS/MS method facilitates simultaneous resolution and detection of authentic standards of 14 native catechin monomers and procyanidins, as well as 24 microbial metabolites. Detection and resolution of an additional 3 procyanidin dimers and 10 metabolites for which standards were not available was achieved. Elution and adequate resolution of both native compounds and metabolites were achieved within 10min. The intraday repeatability for native compounds was between 1.1 and 16.5%, and the interday repeatability for native compounds was between 2.2 and 25%. Intraday and interday repeatability for metabolites was between 0.6 and 24.1% and 1 and 23.9%, respectively. Observed lower limits of quantification for native compounds were ?9-350fmol on-column, and for the microbial metabolites were ?0.8-12,000fmol on-column. Observed lower limits of detection for native compounds were ?4.5-190fmol on-column, and for metabolites were 0.304-6020fmol on-column. For native monomers and procyanidins, extraction recoveries ranged from 38 to 102%. Extraction recoveries for the 9 microbial metabolites tested ranged from 41 to 95%. Data from tissue analysis of rats gavaged with grape seed extract indicate fairly high accumulation of native compounds, primarily monomers and dimers, in the cecum and colon. Metabolite data indicate the progressive nature of microbial metabolism as the digesta moves through the lower GI tract. This method facilitates the high-throughput, sensitive, and simultaneous analysis of both native compounds and their microbial metabolites in biological samples and provides a more efficient means of extraction and analysis than previous methods. PMID:24704909

  13. Determination of anthelmintic drug residues in milk using UPLC-MS/MS with rapid polarity switching

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A new UPLC-MS/MS (ultra-performance liquid chromatography coupled to tandem mass spectrometry) method was developed and validated to detect 38 anthelmintic drug residues, consisting of benzimidazoles, avermectins and flukicides. A modified QuEChERS-type extraction method was developed with an added...

  14. Serum UPLC-MS/MS metabolic profiling in an experimental model for acute-liver injury reveals potential biomarkers for hepatotoxicity

    PubMed Central

    Gonzalez, Esperanza; van Liempd, Sebastiaan; Conde-Vancells, Javier; Gutierrez-de Juan, Virginia; Perez-Cormenzana, Miriam; Mayo, Rebeca; Berisa, Agustin; Alonso, Cristina; Marquez, Cesar A.; Barr, Jonathan; Lu, Shelly C.; Mato, Jose M.

    2012-01-01

    A key interest in clinical diagnosis and pharmaceutical industry is to have a repertoire of noninvasive biomarkers to—individually or in combination—be able to infer or predict the degree of liver injury caused by pathological conditions or drugs. Metabolomics—a comprehensive study of global metabolites—has become a highly sensitive and powerful tool for biomarker discovery thanks to recent technological advances. An ultra-performance liquid chromatography/time-of-flight tandem mass spectrometry (UPLC/TOF MS/MS)-based metabolomics approach was employed to investigate sera from galactosamine-treated rats to find potential biomarkers for acute liver injury. Hepatic damage was quantified by determining serum transaminase activity and in situ liver histological lesions. Principal component analysis in combination with coefficient of correlation analysis was used for biomarker selection and identification. According to the data, serum levels of several metabolites including glucose, amino acids, and membrane lipids were significantly modified, some of them showing a high correlation with the degree of liver damage determined by histological examination of the livers. In conclusion, this study supports that UPLC-MS/MS based serum metabolomics in experimental animal models could be a powerful approach to search for biomarkers for drug- or disease-induced liver injury. PMID:23139648

  15. Determination of kurarinone in rat plasma by UPLC-MS/MS.

    PubMed

    Zhang, Wei-Min; Li, Rui-Fang; Qiu, Jian-Fei; Zhang, Zhi-Yin; Wang, Hong-Bo; Bian, Lu; Lei, Jia-Hui

    2015-04-01

    A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine kurarinone in rat plasma using chlorzoxazone as the internal standard (IS). Sample preparation was accomplished through a liquid-liquid extraction procedure with ethyl acetate to 0.2mL plasma sample. The analyte and IS were separated on an Acquity UPLC BEH C18 column (2.1mm×50mm, 1.7?m) with the mobile phase of acetonitrile and 1% formic acid in water with gradient elution at a flow rate of 0.40mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by multiple reactions monitoring (MRM) of the transitions at m/z 437.0?301.2 for kurarinone and m/z 168.1?132.1 for IS. The linearity of this method was found to be within the concentration range of 20-2000ng/mL with a lower limit of quantification of 20ng/mL. Only 3.0min was needed for an analytical run. The matrix effect was 94.7-107.2% for kurarinone. The intra- and inter-day precision (RSD%) were less than 8.2% and accuracy (RE%) was within ±9.0%. The recovery ranged from 77.3% to 85.6%. Kurarinone was sufficiently stable under all relevant analytical conditions. The method was also successfully applied to the pharmacokinetic study of kurarinone in rats. PMID:25703950

  16. Monitoring sea lamprey pheromones and their degradation using rapid stream-side extraction coupled with UPLC-MS/MS

    USGS Publications Warehouse

    Wang, Huiyong Wang; Johnson, Nicholas; Bernardy, Jeffrey; Hubert, Terry; Li, Weiming

    2013-01-01

    Pheromones guide adult sea lamprey (Petromyzon marinus) to suitable spawning streams and mates, and therefore, when quantified, can be used to assess population size and guide management. Here, we present an efficient sample preparation method where 100 mL of river water was spiked with deuterated pheromone as an internal standard and underwent rapid field-based SPE and elution in the field. The combination of field extraction with laboratory UPLC-MS/MS reduced the sample consumption from 1 to 0.1 L, decreased the sample process time from more than 1 h to 10 min, and increased the precision and accuracy. The sensitivity was improved more than one order of magnitude compared with the previous method. The influences of experimental conditions were assessed to optimize the separation and peak shapes. The analytical method has been validated by studies of stability, selectivity, precision, and linearity and by the determination of the limits of detection and quantification. The method was used to quantify pheromone concentration from five streams tributary to Lake Ontario and to estimate that the environmental half-life of 3kPZS is about 26 h.

  17. Monitoring sea lamprey pheromones and their degradation using rapid stream-side extraction coupled with UPLC-MS/MS.

    PubMed

    Wang, Huiyong; Johnson, Nicholas; Bernardy, Jeffrey; Hubert, Terry; Li, Weiming

    2013-05-01

    Pheromones guide adult sea lamprey (Petromyzon marinus) to suitable spawning streams and mates, and therefore, when quantified, can be used to assess population size and guide management. Here, we present an efficient sample preparation method where 100 mL of river water was spiked with deuterated pheromone as an internal standard and underwent rapid field-based SPE and elution in the field. The combination of field extraction with laboratory UPLC-MS/MS reduced the sample consumption from 1 to 0.1 L, decreased the sample process time from more than 1 h to 10 min, and increased the precision and accuracy. The sensitivity was improved more than one order of magnitude compared with the previous method. The influences of experimental conditions were assessed to optimize the separation and peak shapes. The analytical method has been validated by studies of stability, selectivity, precision, and linearity and by the determination of the limits of detection and quantification. The method was used to quantify pheromone concentration from five streams tributary to Lake Ontario and to estimate that the environmental half-life of 3kPZS is about 26 h. PMID:23529861

  18. UPLC-MS/MS determination of thiamphenicol in human plasma and its application to a pharmacokinetic study.

    PubMed

    Wang, Zhe; Yang, Hui; Sun, Wei; Huang, Cheng-ke; Cui, Xiao; Qiu, Xiang-jun; Lian, Qing-quan; Wang, Zeng-shou

    2014-09-15

    A sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine thiamphenicol (TAP) in human plasma using chlorzoxazone as the internal standard (IS). Sample preparation was accomplished through a liquid-liquid extraction procedure with ethyl acetate to precipitation of plasma protein, and to a 0.1 mL plasma sample. The analyte and IS were separated on an Acquity UPLC BEH C18 column (2.1 mm × 50 mm, 1.7 ?m) with the mobile phase of acetonitrile and 1% formic acid in water with gradient elution at a flow rate of 0.40 mL/min. The detection was performed on a triple quadrupole tandem mass spectrometer equipped with electrospray ionization (ESI) by multiple reactions monitoring (MRM) of the transitions at m/z 354.3?185.1 for TAP and m/z 168.1?132.1 for IS. The linearity of this method was found to be within the concentration range of 10-8000 ng/mL with a lower limit of quantification of 10 ng/mL. 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 TAP in healthy Chinese volunteers after oral administration. PMID:25129408

  19. Rapid determination of fenoldopam in human plasma by UPLC-MS/MS for pharmacokinetic analysis in patients.

    PubMed

    Wang, Xipei; Zheng, Zhijie; He, Guodong; Mai, Liping; Zhou, Zhiling; Zhong, Shilong; Lin, Qiuxiong; Shan, Zhixin; Deng, Chunyu; Yang, Min; Yu, Xiyong

    2015-01-26

    We developed and validated a rapid, selective, and sensitive ultra-performance liquid-chromatography mass-spectrometry (UPLC-MS/MS) method for quantifying fenoldopam in human plasma for pharmacokinetic studies. Fenoldopam and the internal-standard (IS), oxazepam, were isolated from human plasma by liquid-liquid extraction using ethyl acetate after alkalization, and were separated on a 2.1×100 mm Acquity UPLC HSS T3 C18 column (inside diameter, 1.8 ?m) using a mobile phase of water (0.05% formic acid) and acetonitrile gradient elution. The fenoldopam and IS were eluted at 1.07 and 2.32 min, respectively. Quantification was performed using positive-ion electrospray-ionization (ESI), and the fenoldopam and IS responses were optimized at the m/z 306.16?107.10 and m/z 287.1?241.01 transitions, respectively. The assay was validated over the linear range of 0.1-40 ng/mL fenoldopam with intra- and interassay precision <13.21%. The matrix effect of normal and hemolyzed plasma was 94.9-101.6%. Fenoldopam was stable for ?34 days at -70 °C in normal and hemolyzed plasma containing ascorbic acid as a stabilizer. This method can be successfully applied in pharmacokinetic studies of fenoldopam in hypertensive patients. PMID:25531873

  20. UPLC-MS/MS determination of phentolamine in human plasma and its application to a pharmacokinetic study.

    PubMed

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

    2014-11-01

    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

  1. Pharmacokinetics and tissue distribution model of cabozantinib in rat determined by UPLC-MS/MS.

    PubMed

    Wang, Xianqin; Wang, Shuanghu; Lin, Feiyan; Zhang, Qingwei; Chen, HuiLing; Wang, Xianchuan; Wen, Congcong; Ma, Jianshe; Hu, Lufeng

    2015-03-01

    Cabozantinib (XL184) is a novel small molecule inhibitor of receptor tyrosine kinases (RTKs) targeted at mesenchymal-epithelial transition factor (MET). In order to study the pharmacokinetics and tissue distribution in rat, a specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed with midazolam as internal standard. The calibration curves in plasma and tissues were linear in the range of 5-5000ng/mL (r(2)>0.99). The recoveries were better than 80.4% and matrix effects ranged from 96.9% to 105.1%. Then, the developed UPLC-MS/MS method was applied to determine the concentration of XL184 in blood and tissues. The pharmacokinetics of four different dosages (iv 5, 10mg/kg and ig 15, 30mg/kg) revealed that XL184 was eliminated slowly, the t1/2 was longer than 10h and the absolute bioavailability was 25.6±8.3%. The concentration distribution of XL184 in tissues was liver>lung>kidney>spleen>heart. Based on the concentration-time of XL184 in tissues, a BP-ANN distribution model was developed with good performance, and can be used to predict the concentration of XL184 in tissues. PMID:25638029

  2. Ultrafast quantification of ?-lactam antibiotics in human plasma using UPLC-MS/MS.

    PubMed

    Carlier, Mieke; Stove, Veronique; De Waele, Jan J; Verstraete, Alain G

    2015-01-26

    There is an increasing interest in monitoring plasma concentrations of ?-lactam antibiotics. The objective of this work was to develop and validate a fast ultra-performance liquid chromatographic method with tandem mass spectrometric detection (UPLC-MS/MS) for simultaneous quantification of amoxicillin, cefuroxime, ceftazidime, meropenem and piperacillin with minimal turn around time. Sample clean-up included protein precipitation with acetonitrile containing 5 deuterated internal standards, and subsequent dilution of the supernatant with water after centrifugation. Runtime was only 2.5 min. Chromatographic separation was performed on a Waters Acquity UPLC system using a BEH C18 column (1.7 ?m, 100 mm × 2.1 mm) applying a binary gradient elution of water and methanol both containing 0.1% formic acid and 2 mmol/L ammonium acetate on a Water TQD instrument in MRM mode. All compounds were detected in electrospray positive ion mode and could be quantified between 1 and 100 mg/L for amoxicillin and cefuroxime, between 0.5 and 80 mg/L for meropenem and ceftazidime, and between 1 and 150 mg/L for piperacillin. The method was validated in terms of precision, accuracy, linearity, matrix effect and recovery and has been compared to a previously published UPLC-MS/MS method. PMID:25531875

  3. Metabolomic Analysis of Diet-Induced Type 2 Diabetes Using UPLC/MS Integrated with Pattern Recognition Approach

    PubMed Central

    Sun, Hui; Zhang, Shuxiang; Zhang, Aihua; Yan, Guangli; Wu, Xiuhong; Han, Ying; Wang, Xijun

    2014-01-01

    Metabolomics represents an emerging discipline concerned with comprehensive assessment of small molecule endogenous metabolites in biological systems and provides a powerful approach insight into the mechanisms of diseases. Type 2 diabetes (T2D), called the burden of the 21st century, is growing with an epidemic rate. However, its precise molecular mechanism has not been comprehensively explored. In this study, we applied urinary metabolomics based on the UPLC/MS integrated with pattern recognition approaches to discover differentiating metabolites, to characterize and explore metabolic pathway disruption in an experimental model for high-fat-diet induced T2D. Six differentiating urinary metabolites were found in the negative mode, and two (2-(4-hydroxy-3-methoxy-phenyl) acetaldehyde sulfate, 2-phenylethanol glucuronide) of which were identified involving the key metabolic pathways linked to pentose and glucuronate interconversions, starch, sucrose metabolism and tyrosine metabolism. Our study provides new insight into pathophysiologic mechanisms and may enhance the understanding of T2D pathogenesis. PMID:24671089

  4. Method development and validation for pharmacokinetic and tissue distributions of ellagic acid using ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS).

    PubMed

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

    2014-01-01

    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

  5. Photodegradation assessment of ciprofloxacin, moxifloxacin, norfloxacin and ofloxacin in the presence of excipients from tablets by UPLC-MS/MS and DSC

    PubMed Central

    2013-01-01

    Background Ciprofloxacin (CIP), moxifloxacin (MOX), norfloxacin (NOR) and ofloxacin (OFL), are the antibacterial synthetic drugs, belonging to the fluoroquinolones group. Fluoroquinolones are compounds susceptible to photodegradation process, which may lead to reduction of their antibacterial activity and to induce phototoxicity as a side effect. This paper describes a simple, sensitive UPLC-MS/MS method for the determination of CIP, MOX, NOR and OFL in the presence of photodegradation products. Results Chromatographic separations were carried out using the Acquity UPLC BEH C18 column; (2.1?×?100 mm, 1.7 ?m particle size). The column was maintained at 40°C, and the following gradient was used: 0 min, 95% of eluent A and 5% of eluent B; 10 min, 0% of eluent A and 100% of eluent B, at a flow rate of 0.3 mL min-1. Eluent A: 0.1% (v/v) formic acid in water; eluent B: 0.1% (v/v) formic acid in acetonitrile. The method was validated and all the validation parameters were in the ranges acceptable by the guidelines for analytical method validation. The photodegradation of examined fluoroquinolones in solid phase in the presence of excipients followed kinetic of the first order reaction and depended upon the type of analyzed drugs and coexisting substances. Photodegradation process of analyzed drugs was confirmed by differential scanning calorimetry. In addition, the identification of degradation products was carried out by mass spectrometry. Conclusion The developed UPLC-MS/MS method enables the determination of CIP, MOX, NOR and OFL in the presence of photodegradation products and identification of photodegradation products. PMID:23899303

  6. A method of analysis for T-2 toxin and neosolaniol by UPLC-MS/MS in apple fruit inoculated with Trichothecium roseum.

    PubMed

    Tang, Yamei; Xue, Huali; Bi, Yang; Li, Yongcai; Wang, Yi; Zhao, Ying; Shen, Keping

    2015-04-01

    Trichothecenes are one of the most important groups of mycotoxins produced by Trichothecium roseum, which causes core rot of apple. A reliable and sensitive method was developed and successfully applied for the rapid detection of trichothecenes including T-2 toxin and neosolaniol in harvested apple using UPLC-MS/MS. After the extraction of the two mycotoxins from the apple matrix with methanol/water (80/20, v/v), the concentrated extracts were cleaned-up by PriboFast M270 columns and then analysed by UPLC-MS/MS. T-2 toxin and neosolaniol were effectively separated as unique peaks. The validity of this method was established by its linearity (R(2) ? 0.9995), precision (relative standard deviation ? 3.6%), accuracy, selectivity, limit of detection of 2-5 ?g kg(-1), limit of quantification of 5-10 ?g kg(-1) and average recovery of 73-96%. Levels of T-2 toxin were found in the range 7.1-128.4 µg kg(-1) in the core rot lesion of three cultivars apple (cvs. Red Delicious, Fuji and Ralls). T-2 was detected not only in the lesion, but also in the tissue without any disease symptoms. However, neosolaniol was only detected in the lesion on 'Red Delicious' apples. In addition, the concentration of T-2 toxin in the susceptible cultivar (cv. Fuji) was significantly higher than that in the resistant one (cv. Ralls). This method proved to be suitable at detecting T-2 and neosolaniol simultaneously in apples infected with T. roseum. PMID:25254921

  7. Development and validation of an UPLC-MS/MS method for the quantification of ethoxzolamide in blood, brain tissue, and bioequivalent buffers: Applications to absorption, brain distribution, and pharmacokinetic studies.

    PubMed

    Gao, Song; Zhao, Jing; Yin, Taijun; Ma, Yong; Xu, Beibei; Moore, Anthony N; Dash, Pramod K; Hu, Ming

    2015-04-01

    The purpose of this study is to develop and validate an UPLC-MS/MS method to quantify ethoxzolamide in plasma (EZ) and apply the method to absorption, brain distribution, as well as pharmacokinetic studies. A C18 column was used with 0.1% of formic acid in acetonitrile and 0.1% of formic acid in water as the mobile phases to resolve EZ. The mass analysis was performed in a triple quadrupole mass spectrometer using multiple reaction monitoring (MRM) with positive scan mode. The results show that the linear range of EZ is 4.88-10,000.00nM. The intra-day variance is less than 12.43% and the accuracy is between 88.88 and 108.00%. The inter-day variance is less than 12.87% and accuracy is between 89.27 and 115.89%. Protein precipitation was performed using methanol to extract EZ from plasma and brain tissues. Only 40?L of plasma is needed for analysis due to the high sensitivity of this method, which could be completed in less than three minutes. This method was used to study the pharmacokinetics of EZ in SD rats, and the transport of EZ in Caco-2 and MDCK-MDR1 overexpressing cell culture models. Our data show that EZ is not a substrate for p-glycoprotein (P-gp) and its entry into the brain may not limited by the blood-brain barrier. PMID:25706567

  8. Simultaneous determination of mequindox, quinocetone, and their major metabolites in chicken and pork by UPLC-MS/MS.

    PubMed

    Li, Yanshen; Liu, Kaili; Beier, Ross C; Cao, Xingyuan; Shen, Jianzhong; Zhang, Suxia

    2014-10-01

    This report presents a UPLC-MS/MS method for determination of mequindox (MEQ), quinocetone (QCT) and their 11 metabolites in chicken and pork samples. Following extraction process with acetonitrile-ethyl acetate, acidulation, and re-extraction with ethyl acetate in turn, target analytes were further purified using C18 solid phase extraction (SPE) cartridges for UPLC-MS/MS analysis. Validation was processed with mean recoveries from 69.1% to 113.3% with intra-day relative standard deviation (RSD) <14.7%, inter-day RSD <19.2%, and limit of detection between 0.05 and 1.0 ?g/kg for each analytes. The verified method was successfully applied to the quantitative determination of commercial samples. This developed procedure will help to control food animal products with MEQ and QCT residues, and facilitate further pharmacokinetic and residue studies of similar quinoxaline-1,4-dioxide veterinary drugs. PMID:24799224

  9. Determination of Glucocorticoids in UPLC-MS in Environmental Samples from an Occupational Setting

    PubMed Central

    Oddone, Enrico; Negri, Sara; Bellinzona, Massimo; Martino, Silvia; Di Tuccio, Marcello; Grignani, Elena; Cottica, Danilo; Imbriani, Marcello

    2015-01-01

    Occupational exposures to glucocorticoids are still a neglected issue in some work environments, including pharmaceutical plants. We developed an analytical method to quantify simultaneously 21 glucocorticoids using UPLC coupled with mass spectrometry to provide a basis to carry out environmental monitoring. Samples were taken from air, hand-washing tests, pad-tests and wipe-tests. This paper reports the contents of the analytical methodology, along with the results of this extensive environmental and personal monitoring of glucocorticoids. The method in UPLC-MS turned out to be suitable and effective for the aim of the study. Wipe-test and pad-test desorption was carried out using 50?mL syringes, a simple technique that saves time without adversely affecting analyte recovery. Results showed a widespread environmental pollution due to glucocorticoids. This is of particular concern. Evaluation of the dose absorbed by each worker and identification of a biomarker for occupational exposure will contribute to assessment and prevention of occupational exposure.

  10. Large Scale Non-targeted Metabolomic Profiling of Serum by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS)

    PubMed Central

    Broeckling, Corey D.; Heuberger, Adam L.; Prenni, Jessica E.

    2013-01-01

    Non-targeted metabolite profiling by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS) is a powerful technique to investigate metabolism. The approach offers an unbiased and in-depth analysis that can enable the development of diagnostic tests, novel therapies, and further our understanding of disease processes. The inherent chemical diversity of the metabolome creates significant analytical challenges and there is no single experimental approach that can detect all metabolites. Additionally, the biological variation in individual metabolism and the dependence of metabolism on environmental factors necessitates large sample numbers to achieve the appropriate statistical power required for meaningful biological interpretation. To address these challenges, this tutorial outlines an analytical workflow for large scale non-targeted metabolite profiling of serum by UPLC-MS. The procedure includes guidelines for sample organization and preparation, data acquisition, quality control, and metabolite identification and will enable reliable acquisition of data for large experiments and provide a starting point for laboratories new to non-targeted metabolite profiling by UPLC-MS. PMID:23524330

  11. Pharmacokinetics of ketorolac loaded to polyethylcyanoacrylate nanoparticles using UPLC MS/MS for its determination in rats.

    PubMed

    Radwan, M A; AlQuadeib, B T; Aloudah, N M; Aboul Enein, H Y

    2010-09-15

    Polyethylcyanoacrylate (PECA) nanoparticles (NPs) have been employed as biodegradable polymeric carriers for oral (PO) delivery of ketorolac. The nanoparticles were prepared by polymerization technique at room temperature in a continuous aqueous phase at pH 2.5. This polymerization technique was able to hold 76-96% of ketorolac and the drug loading was a monomer concentration dependent. The feasibility of PECA NPs as PO controlled drug delivery systems of ketorolac was investigated in two groups of rats which were given orally either ketorolac tromethamine solution (1.5 mg/kg) or the selected ketorolac NPs aqueous dispersion (1.6 mg/kg). Ketorolac plasma concentrations were measured by a new fully validated specific, precise and accurate ultra-performance liquid chromatography tandem mass spectrometry (UPLC MS/MS) assay. The detection was performed on Waters TQ detector via negative electrospray ionization in a multiple reaction monitoring mode. Linear response (r(2)> or =0.995) was observed over the range of 10-10,000 ng/ml of ketorolac, with the lower limit of quantification of 5 ng/ml with 1 microl injection volume. The intra- and inter-day precision (relative standard deviation, R.S.D.) values were <10% and the accuracy (relative error) was < or =8 for ketorolac concentrations. The drug solution is rapidly absorbed, distributed, and eliminated and shows a monophasic elimination phase. The assay was sensitive to follow pharmacokinetics of ketorolac in rats up to 24 h after a PO dose of its aqueous solution or NPs suspension. After NPs administration the mean Cmax, 5.0+/-1.3 mg/l, was attained at 1 h. The drug was successfully maintained around this elevated plasma drug concentration up to 6h (>2t(1/2)), in rats. The AUC was significantly higher after the NPs suspension than the solution of ketorolac. This present study provides evidence that the sorption of ketorolac to PECA NPs could control the drug release/elimination in rats. PMID:20600724

  12. Drug screening in medical examiner casework by high-resolution mass spectrometry (UPLC-MSE-TOF).

    PubMed

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

    2013-10-01

    Postmortem drug findings yield important analytical evidence in medical examiner casework, and chromatography coupled with nominal mass spectrometry (MS) serves as the predominant general unknown screening approach. We report screening by ultra performance liquid chromatography (UPLC) coupled with hybrid quadrupole time-of-flight mass spectrometer (MS(E)-TOF), with comparison to previously validated nominal mass UPLC-MS and UPLC-MS-MS methods. UPLC-MS(E)-TOF screening for over 950 toxicologically relevant drugs and metabolites was performed in a full-spectrum (m/z 50-1,000) mode using an MS(E) acquisition of both molecular and fragment ion data at low (6 eV) and ramped (10-40 eV) collision energies. Mass error averaged 1.27 ppm for a large panel of reference drugs and metabolites. The limit of detection by UPLC-MS(E)-TOF ranges from 0.5 to 100 ng/mL and compares closely with UPLC-MS-MS. The influence of column recovery and matrix effect on the limit of detection was demonstrated with ion suppression by matrix components correlating closely with early and late eluting reference analytes. Drug and metabolite findings by UPLC-MS(E)-TOF were compared with UPLC-MS and UPLC-MS-MS analyses of postmortem blood in 300 medical examiner cases. Positive findings by all methods totaled 1,528, with a detection rate of 57% by UPLC-MS, 72% by UPLC-MS-MS and 80% by combined UPLC-MS and UPLC-MS-MS screening. Compared with nominal mass screening methods, UPLC-MS(E)-TOF screening resulted in a 99% detection rate and, in addition, offered the potential for the detection of nontargeted analytes via high-resolution acquisition of molecular and fragment ion data. PMID:23999055

  13. Determination of ?-6 and ?-3 PUFA metabolites in human urine samples using UPLC/MS/MS.

    PubMed

    Sasaki, Ai; Fukuda, Hayato; Shiida, Narumi; Tanaka, Nobuaki; Furugen, Ayako; Ogura, Jiro; Shuto, Satoshi; Mano, Nariyasu; Yamaguchi, Hiroaki

    2015-02-01

    The ?-6 and ?-3 polyunsaturated fatty acids (PUFAs) such as arachidonic acid (AA), eicosapentaenoic acid (EPA), and docosahexaenoic acid (DHA) are the precursors of various bioactive lipid mediators including prostaglandins, thromboxanes, leukotrienes, hydroxyeicosatetraenoic acid, isoprostanes, lipoxins, and resolvins (Rvs). These lipid mediators play important roles in various physiological and pathological processes. The quantitative determination of PUFA metabolites seems necessary for disease research and for developing biomarkers. However, there is a paucity of analytical methods for the quantification of ?-6 and ?-3 PUFA metabolites-the specialized pro-resolving mediators (SPMs) present in the human urine. We developed a method for the quantification of ?-6 and ?-3 PUFA metabolites present in human urine using ultra-performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS). The developed method shows good linearity, with a correlation coefficient >0.99 for all of the analytes. The validation results indicate that our method is adequately reliable, accurate, and precise. The method was successfully used to examine urine samples obtained from 43 healthy volunteers. We could identify 20 PUFA metabolites, and this is the first report of the quantitative determination of RvD1, 17(R)-RvD1, 11-dehydro thromboxane B3, RvE2, and 5(S)-HETE in human urine. The urinary 8-iso PGF2? and PGE2 levels were significantly higher in the men smokers than in the men nonsmokers (p?

  14. Determination of a novel anticancer c-Met inhibitor LS-177 in rat plasma and tissues with a validated UPLC-MS/MS method: application to pharmacokinetics and tissue distribution study.

    PubMed

    Ju, Ping; Liu, Zhenzhen; Jiang, Yu; Zhao, Simin; Zhang, Lunhui; Zhang, Yuanyuan; Gu, Liqiang; Tang, Xing; Bi, Kaishun; Chen, Xiaohui

    2014-12-01

    LS-177 is a novel small-molecule kinase inhibitor employed to interrupt the c-Met signaling pathway. A rapid and sensitive ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for determination of LS-177 in rat plasma and tissues. The biosamples were extracted by liquid-liquid extraction with methyl tert-butyl ether and separated on a C18 column (50?×?4.6?mm, 2.6?µm) using a gradient elution mobile phase consisting of acetonitrile-0.1% formic acid water. Under the optimal conditions, the selectivity of the method was satisfactory with no endogenous interference. The intraday and interday precisions (relative standard deviation) were <10.5% and the accuracy (relative error) was from -12.5 to 12.5% at all quality control levels. Excellent recovery and negligible matrix effects were observed. Stability studies showed that LS-177 was stable during the preparation and analytical processes. The UPLC-MS/MS method was successfully applied to pharmacokinetic and tissue distribution studies. The results indicated that there was no significant drug accumulation after multiple-dose oral administration of LS-177. The tissue distribution study exhibited significant higher uptakes of LS-177 in stomach, intestine, lung and liver among all of the tissues. The results in pharmacokinetics and tissue distribution may provide a meaningful basis for clinical application. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25472760

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

    PubMed

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

    2014-09-17

    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

  16. 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

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

    2014-08-13

    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

  17. An UPLC-MS/MS method for determination of solasonine in rat plasma and its application of a pharmacokinetic and bioavailability study.

    PubMed

    Chen, Yuanyuan; Zhang, Shuangshuang; Chen, Dahui; Zhou, Mi; Zheng, Jing; Xiang, Zheng

    2015-03-15

    Solasonine, a known glycoalkaloid, is a potential anti-cancer agent. In this work, a simple, sensitive and fast ultra performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the quantitative determination of solasonine in rat plasma. Plasma samples were processed with a protein precipitation. The separation was achieved by an ACQUITY HSS T3 (100×2.1mm, 1.8?m) column with a gradient mobile phase consisting of 0.1% formic acid and acetonitrile. Detection was carried out using positive-ion electrospray tandem mass spectrometry via multiple reaction monitoring (MRM). The validated method had an excellent linearity in the range of 0.1-500ng/mL (R(2)>0.994) with a low limit of detection (0.1ng/mL) and lower limit of quantification (0.5ng/mL). The extraction recovery was in the range of 92.4-94.9% for solasonine and 91.9% for dendrobine (internal standard, IS). The intra- and inter-day precision was below 9.8% and accuracy was from 86.0% to 94.3%. No notable matrix effect and astaticism was observed for solasonine. The method has been successfully applied to a pharmacokinetic and bioavailability study of solasonine in rats for the first time, which provides the basis for the further development and application of solasonine. PMID:25645955

  18. Direct UPLC-MS-MS validated method for the quantification of 5-aminolevulinic acid: application to in-vitro assessment of colonic-targeted oral tablets.

    PubMed

    Alsarra, Ibrahim A; Yassin, Alaa Eldeen B; Abdel-Hamid, Magdi; Alanazi, Fars K; Aljuffali, Ibrahim A

    2011-01-01

    A reliable, sensitive, specific, and rapid ultra-performance liquid chromatography-tandem mass spectrometric (UPLC-MS-MS) method was developed for the determination of 5-aminolevulinic acid (5-ALA) in orally-administered colonic delivery system. The prepared system is a compression-coated tablet using granulated chitosan as the coat layer. L-Tyrosine (TYR) was used as an internal standard with no need for derivatization. The chromatographic system consisted of Acquity UPLC BEH C18 column and isocratic mobile phase composed of acetonitrile and 0.1% formic acid with a flow rate of 2.5 min. The assay was based on ESI+ mode in a multiple reaction monitoring (MRM) transitions at m/z 132.08 > 86.0 and m/z 132.08 > 114.0 and m/z 182.1 > 91.2 for 5-ALA and TYR, respectively. Limit of quantification was 5.0 ng/mL and the calibration curve was linear (r(2) = 0.994). Within-run precision and between-run repeatability were expressed as relative standard deviation and were lower than 2.5%. The recoveries from control samples were > 95%. The method was successfully applied for evaluation in assay and release profile of 5-ALA colon targeted tablets media containing suspended rat cecal contents pH 6.8 medium (colonic) for colonic delivery. PMID:21682991

  19. 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

    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

    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

  20. [Metabonomic study on protective effect of ethanol extracts of drynariae rhizoma on osteoporosis in rats urine by using UPLC-MS/MS].

    PubMed

    Zhang, Shangshang; Liu, Xinyu; Zheng, Shuning; Jiang, Minyan; Xin, Changying; Lu, Xiumei; Li, Famei; Xiong, Zhili

    2012-03-01

    This paper was designed to study metabonomic characters of the osteoporosis induced by high dose of hydrocortisone and the protective effects of Drynariae Rhizoma, which can replenish the kidney and strengthen the bones. A urinary metabonomics method based on ultra-performance liquid chromatography coupled with mass spectrometry (UPLC-MS/MS) was developed. Clear separation of healthy control group, model group and treatment group was achieved by using the principal components analysis (PCA) and 9 significantly changed metabolites were identified as potential biomarkers of osteoporosis. Compared with the health control group, the model group rats showed lower levels of creatinine, citric acid, azelaic acid, hippurate, tryptophan and indoxyl sulfate together with higher levels of phenylalanine, cresol sulfate and phenaceturic acid. These changes in urinary metabolites suggest that the disorders of amino acid metabolism, energy metabolism, gut microflora and anti-oxidative damage are related to osteoporosis induced by high dose of hydrocortisone and the potential effect of Drynariae Rhizoma on all the four metabolic pathways. PMID:22693913

  1. Fast identification of lipase inhibitors in oolong tea by using lipase functionalised Fe3O4 magnetic nanoparticles coupled with UPLC-MS/MS.

    PubMed

    Zhu, Yuan-Ting; Ren, Xiao-Yun; Yuan, Li; Liu, Yi-Ming; Liang, Jian; Liao, Xun

    2015-04-15

    Oolong tea is an important member in tea family, which claims for various health benefits such as preventing obesity and improving lipid metabolism. In this work, using pancreatic lipase (PL) functionalised magnetic nanoparticles (PL-MNPs) as solid phase extraction absorbent in combination with ultra-high performance liquid chromatography-mass spectrometry (UPLC-MS), we developed a method for rapid screening and identification of lipase inhibitors from oolong tea. Three PL ligands were selectively extracted and identified as (-)-epigallocatechin-3-O-gallate (EGCG), (-)-gallocatechin-3-O-gallate (GCG) and (-)-epicatechin-3-O-gallate (ECG). Their lipase inhibitory activities were significantly higher than those non-ligands. Structure-activity analysis revealed that the presence of a galloyl moiety in the structure was required for binding to PL-MNPs, and therefore, exhibiting a strong inhibition on the enzyme. Taking advantages of the specificity in enzyme binding and the convenience of magnetic separation, this method has great potential for fast screening of lipase inhibitors from natural resources. PMID:25466054

  2. Advantages of on-line SPE coupled with UPLC/MS/MS1 for determining the fate of pesticides and2

    E-print Network

    Paris-Sud XI, Université de

    1 Advantages of on-line SPE coupled with UPLC/MS/MS1 for determining the fate of pesticides and2 techniques were validated for both 18 pesticides22 and their degradates and 17 pharmaceuticals for pesticides and24 metabolites have been obtained, with linearity range up to 1 µg.L-1.The limits of25

  3. Rapid qualitative and quantitative analysis of proanthocyanidin oligomers and polymers by ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    We developed a rapid method with ultra-performance liquid chromatography – tandem mass spectrometry (UPLC-MS/MS) for the qualitative and quantitative analysis of plant proanthocyanidins (PAs) directly from crude plant extracts. The method utilizes a range of cone voltages to achieve the depolymeriza...

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

    PubMed

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

    2014-06-01

    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

  5. 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...

  6. A novel UPLC/MS/MS method for rapid determination of metapristone in rat plasma, a new cancer metastasis chemopreventive agent derived from mifepristone (RU486).

    PubMed

    Chen, Jian-Zhong; Wang, Ji-Chuang; Gao, Yu; Zeng, Rong-Jie; Jiang, Zhou; Zhu, Ye-Wei; Shao, Jing-Wei; Jia, Lee

    2014-07-01

    Mifepristone (RU486) is a chemical abortifacient used by hundreds of millions of women world-wide. It has recently been used in clinical trials for psychotic depression and cancer chemotherapy. Metapristone is the most predominant biological active metabolite of mifepristone, and being developed as a novel cancer metastasis chemopreventive agent based on its unique pharmacological properties. In this study, a novel rapid and sensitive method using UPLC/MS/MS was developed and validated for quantitative analysis of metapristone in plasma, which used less plasma volume and was demonstrated to be more simple and low-cost than the published methods. Metapristone in plasma was recovered by liquid-liquid extraction using 1 mL of ethyl acetate and chromatographic separation was carried on a C?? column at 35 °C, with a gradient mobile phase consisting of methanol and water containing 0.1% (v/v) formic acid at a flow rate of 0.3 mL/min. The mass spectrometric detection was carried out using a triple-quadrupole system via positive electrospray ionization. Multiple reaction monitoring was used for quantitation of m/z transitions from 416.3 to 119.9 for metapristone and from 313.1 to 109 for levonorgestrel (internal standard). Good linearity (r²> 0.9926) was achieved over a concentration range from 7.1 to 2840 ng/mL with a lower limit of quantification of 7.1 ng/mL for metapristone. The intra- and inter-day variations of the assay were 2.4-10.0% relative standard deviation with an accuracy of -5.6 to 8.6% relative error. This newly developed method was successfully applied to a pharmacokinetic study that revealed, for the first time, that there was a significant difference in pharmacokinetic profile between genders. PMID:24682015

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

    Microsoft Academic Search

    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

    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

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

    PubMed

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

    2010-06-15

    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

  9. Development and validation of a systematic UPLC-MS/MS method for simultaneous determination of three phenol impurities in ritonavir.

    PubMed

    Venugopal, N; Vijaya Bhaskar Reddy, A; Madhavi, G

    2014-03-01

    A stability indicating gradient reverse phase UPLC-MS/MS method was developed and validated for the simultaneous determination of three phenol impurities in ritonavir drug substance. The chromatographic separation was performed on Acquity UPLC BEH C18 column (100 mm × 2.1 mm, 1.7 ?m) using gradient elution of 0.05% ammonia in methanol and 5.0 mM ammonium acetate buffer (30:70, v/v) at a flow rate of 0.2 mL/min. Both negative and positive electrospray ionization (ESI) modes were operated simultaneously for the quantification of three phenol impurities. The total run time was 11 min, within which ritonavir and its three impurities were well separated. The developed method was validated as per ICH guidelines with respect to specificity, linearity, limit of detection, limit of quantification, accuracy, precision and robustness. The calibration curves showed a good linearity over the concentration range of 0.3-1.5 ppm for phenol and 0.1-1.5 ppm for both 4-nitrophenol and N-phenoxycarbonyl-L-valine (NPV). The determination coefficient obtained was >0.9998 in each case. The method had very low limit of detection (LOD) and limit of quantification (LOQ) and the accuracy lies between 97.8% and 103.2% for all the three phenol impurities. The developed method was successfully applied for five formulation batches of ritonavir to determine its phenol impurities. PMID:24366213

  10. Simultaneous detection of multiple DNA adducts in human lung samples by isotope-dilution UPLC-MS/MS.

    PubMed

    Monien, Bernhard H; Schumacher, Fabian; Herrmann, Kristin; Glatt, Hansruedi; Turesky, Robert J; Chesné, Christophe

    2015-01-01

    Recent studies have demonstrated that various DNA adducts can be detected in human tissues and fluids using liquid chromatography connected to tandem mass spectrometry (LC-MS/MS). However, the utility of a single DNA adduct as a biomarker in risk assessment is debatable because humans are exposed to many genotoxicants. We established a method to measure DNA adducts derived from 16 ubiquitous genotoxicants and developed an analytical technique for their simultaneous quantification by ultra performance liquid chromatography (UPLC)-MS/MS. Methods for the enrichment of the analytes from DNA hydrolysates and chromatographic separation preceding mass spectrometric analysis were optimized, and the resultant technique was used for the simultaneous analysis of the 16 DNA adducts in human lung biopsy specimens. Eleven adducts (formed by benzo[a]pyrene, 1-methylpyrene, 4-aminobiphenyl, 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine, 1-methoxy-3-indolylmethylglucosinolate, 5-hydroxymethylfurfural, and malondialdehyde) were not detected in any tissue sample (limits of detection: 0.02-7.1 adducts/10(8) nucleosides). 3,N(4)-etheno-2'-deoxycytidine and 1,N(6)-etheno-2'-deoxyadenosine, formed from 2,3-epoxyaldehydes of endogenous lipid peroxidation products, were present in all subjects (16.9-115.3 and 27.2-179/10(8) nucleosides, respectively). The same was true for N(2)-(trans-methylisoeugenol-3'-yl)-2'-deoxyguanosine, the major adduct of methyleugenol (1.7-23.7/10(8) nucleosides). A minor adduct of methyleugenol and two adducts of furfuryl alcohol were detected in several pulmonary specimens. Taken together, we developed a targeted approach for the simultaneous mass spectrometric analyses of 16 DNA adducts, which can be easily extended by adducts formed from other mutagens. The method allowed one to detect adducts of furfuryl alcohol and methyleugenol in samples of human lung. PMID:25423194

  11. Two rapid ultra performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) methods with common sample pretreatment for therapeutic drug monitoring of immunosuppressants compared to immunoassay.

    PubMed

    Tszyrsznic, Wlodzimierz; Borowiec, Agnieszka; Pawlowska, Emilia; Jazwiec, Radoslaw; Zochowska, Dorota; Bartlomiejczyk, Irena; Zegarska, Jolanta; Paczek, Leszek; Dadlez, Michal

    2013-06-01

    Therapeutic drug monitoring of immunosuppressive agents is a critical and essential part of patient therapy after organ transplantation. We have developed high-throughput, robust, and rapid liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) methods with common pretreatment procedures for simultaneous quantification of four immunosuppressive agents (everolimus, sirolimus, tacrolimus, and cyclosporin A) in whole blood and one immunosuppressant (mycophenolic acid) in plasma. The new approach used in this work is based on improved sample preparation procedures allowing the analysis of five immunosuppressive drugs. Whole blood was prepared by transferring 100?L of blood into a 1.5-mL silanized conical test tube. Zinc sulfate solution (150?L), containing deuterated internal standards, was added to perform hemolysis. The samples were vortexing for 10s, followed by the addition of 250?L acetonitrile, containing internal standard for cyclosporin A, to precipitate proteins. The mixture was vortexed for 1min and centrifuged for 2min at 14,000rpm. The whole supernatant was transferred to a vial. To prepare blood plasma, the hemolysis step involving the addition of zinc sulfate was omitted and, instead of acetonitrile, methanol was used as the solvent for the internal standard (mycophenolic acid-d3). The volumes of chemicals used in this procedure were the same as those used in the procedure for immunosuppressants in whole blood. The basic validation parameters for the analytical methods were limits of detection (0.5ng/mL for everolimus, sirolimus and tacrolimus, 25ng/mL for cyclosporin A and 100ng/mL for mycophenolic acid), precision (<15%), recovery (>84%), repeatability and reproducibility. Possible mutual ion suppression was eliminated in the presence of internal standards. The method developed for the quantitation of immunosuppressants in whole blood was used to analyze 276 patient samples containing tacrolimus and 55 samples containing cyclosporin A. The results from LC/MS/MS were compared to those obtained from immunoassays of the same samples. Immunoassays significantly overestimated the concentrations of immunosuppressants. PMID:23584041

  12. An Improved UPLC-MS/MS Platform for Quantitative Analysis of Glycerophosphoinositol in Mammalian Cells

    PubMed Central

    Grauso, Laura; Mariggiò, Stefania; Corda, Daniela; Fontana, Angelo; Cutignano, Adele

    2015-01-01

    The glycerophosphoinositols constitute a class of biologically active lipid-derived mediators whose intracellular levels are modulated during physiological and pathological cell processes. Comprehensive assessment of the role of these compounds expands beyond the cellular biology of lipids and includes rapid and unambiguous measurement in cells and tissues. Here we describe a sensitive and simple liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for quantitative analysis of the most abundant among these phosphoinositide derivatives in mammalian cells, the glycerophosphoinositol (GroPIns). The method has been developed in mouse Raw 264.7 macrophages with limits of quantitation at 3 ng/ml. Validation on the same cell line showed excellent response in terms of linear dynamic range (from 3 to 3,000 ng/ml), intra-day and inter-day precision (coefficient of variation ? 7.10%) and accuracy (between 98.1 and 109.0%) in the range 10-320 ng/ml. As proof of concept, a simplified analytical platform based on this method and external calibration was also tested on four stimulated and unstimulated cell lines, including Raw 264.7 macrophages, Jurkat T-cells, A375MM melanoma cells and rat basophilic leukemia RBL-2H3 cells. The results indicate a wide variation in GroPIns levels among different cell lines and stimulation conditions, although the measurements were always in line with the literature. No significant matrix effects were observed thus indicating that the here proposed method can be of general use for similar determinations in cells of different origin. PMID:25860666

  13. Simultaneous determination of paeoniflorin, albiflorin, ferulic acid, tetrahydropalmatine, protopine, typhaneoside, senkyunolide I in Beagle dogs plasma by UPLC-MS/MS and its application to a pharmacokinetic study after Oral Administration of Shaofu Zhuyu Decoction.

    PubMed

    Huang, Xiaochen; Su, Shulan; Cui, Wenxia; Liu, Pei; Duan, Jin-ao; Guo, Jianming; Li, Zhenhao; Shang, Erxin; Qian, Dawei; Huang, Zhijun

    2014-07-01

    In this present study, a sensitive and rapid UPLC-MS/MS method was developed for simultaneous quantification of paeoniflorin, albiflorin, ferulic acid, tetrahydropalmatine, protopine, typhaneoside and senkyunolide I in Beagle dog plasma after oral administration of the Shao-Fu-Zhu-Yu Decoction. Chloramphenicol and clarithromycin were used as internal standards. Plasma samples were processed by protein precipitation with methanol. The separation was performed on an Acquity BEH C18 column (100mm×2.1mm, 1.7?m) at a flow-rate of 0.4mL/min, using 0.1% formic acid-acetonitrile as mobile phase. Method validation was performed as per Food and Drug Administration guidelines and the results met the acceptance criteria. After validation, this method was successfully applied to a pharmacokinetic study. The results showed that the apparent plasma clearance of paeoniflorin, albiflorin, typhaneoside and senkyunolide I were significantly higher than others. Double peak was observed in plasma concentration curves of tetrahydropalmatine, the ferulic acid had a good absorption in Beagle dog plasma, and senkyunolide I was detected in plasma from the first blood sampling time (15min) and rapidly reached Tmax. The compound of typhaneoside has a low bioavailability according to the results. PMID:24907546

  14. Determination of sunitinib and its active metabolite, N-desethyl sunitinib in mouse plasma and tissues by UPLC-MS/MS: assay development and application to pharmacokinetic and tissue distribution studies.

    PubMed

    Chen, Xiao; Wang, Zhong; Liu, Mengping; Liao, Min; Wang, Xinfeng; Du, Huajuan; Chen, Jiefeng; Yao, Meicun; Li, Qing

    2015-05-01

    A simple, sensitive and specific method using ultraperformance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) was developed to determine sunitinib and N-desethyl sunitinib in mouse plasma and tissues. The analytes were separated by an isocratic mobile phase consisting of acetonitrile and buffer solution (water with 0.1% formic acid and 5?m m ammonium acetate; 40: 60, v/v) running at a flow rate of 0.35?mL/min for 2?min. Quantification was performed using a mass spectrometer by multiple reaction monitoring in positive electrospray ionization mode. The transition was monitored at m/z 399???283, m/z 371???283 and m/z 327???270 for sunitinib, N-desethyl sunitinib and internal standard, respectively. Calibration curves were linear over concentration ranges of 2-500, 0.5-50 and 1-250?ng/mL for plasma, heart and other biosamples. The method was successfully applied to animal experiments. The pharmacokinetic study indicated that sunitinib was eliminated quickly in mice with a half-life of 1.2?h; tissue distribution data showed more sunitinib and its metabolite in liver, spleen and lung, which provided reference for further study. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25294592

  15. UPLC-MS/MS determination of ephedrine, methylephedrine, amygdalin and glycyrrhizic acid in Beagle plasma and its application to a pharmacokinetic study after oral administration of Ma Huang Tang.

    PubMed

    Yan, Tianhua; Fu, Qiang; Wang, Jing; Ma, Shiping

    2015-02-01

    An ultra performance liquid chromatography-mass spectrometric (UPLC-MS) method was developed to investigate the pharmacokinetic properties of ephedrine, methylephedrine, amygdalin, and glycyrrhizic acid after oral gavage of Ma Huang Tang (MHT) in Beagles. Beagle plasma samples were pretreated using liquid-liquid extraction, and chromatographic separation was performed on a C18 column using a linear gradient of water-formic acid mixture (0.1%). The pharmacokinetic parameters of ephedrine, methylephedrine, amygdalin, and glycyrrhizic acid from MHT in Beagles were quantitatively determined by UPLC with tandem mass detector. The qualitative detection of the four compounds was accomplished by selected ion monitoring in negative/positive ion modes electrospray ionization-mass spectrometry (ESI-MS). Detection was based on multiple reaction monitoring with the precursor-to-product ion transitions m/z 166.096-116.983 (ephedrine), m/z 179.034-146.087 (methylephedrine), m/z 456.351-323.074 (amygdalin), and m/z 821.606-351.062 (glycyrrhizic acid). The selectivity, sensitivity, linearity, accuracy, precision, extraction recovery, ion suppression, and stability were within the acceptable ranges. The method described was successfully applied to reveal the pharmacokinetic properties of ephedrine, methylephedrine, amygdalin, and glycyrrhizic acid after oral gavage of MHT in Beagles. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24824649

  16. Effects of borneol on the pharmacokinetics of geniposide in cortex, hippocampus, hypothalamus and striatum of conscious rat by simultaneous brain microdialysis coupled with UPLC-MS.

    PubMed

    Yu, Bin; Ruan, Ming; Cui, Xiao-bing; Guo, Jian-Ming; Xu, Li; Dong, Xiao-Ping

    2013-04-15

    It has been verified that borneol could promote the accumulation of other drugs in the whole brain. In this study, a microdialysis sampling system coupled with UPLC-MS was developed to evaluate the delivery of geniposide to four brain regions (cortex, hippocampus, hypothalamus and striatum) of conscious rats in the absence/presence of borneol: rats were administrated with geniposide alone (300mg/kg, iv) or administrated with both geniposide and borneol (0.2g/kg, ig). The dialysate collected from specific brain area was analyzed by a UPLC-MS system: separated on a BEH C18 column (50mm×2.1mm id, 1.7?m) within 1.5min, and detected in positive ion electrospray mode. The calibration curve was in good linearity over the concentration range of 0.009-90?g/mL. The inter- and intra-day accuracies were within ±10%, and the precisions were within 9.13%. The established method was applied to study the brain pharmacokinetics of geniposide and the results demonstrated that borneol markedly facilitated the delivery of geniposide to hippocampus and hypothalamus, but slightly hampered its delivery in cortex. PMID:23417086

  17. [Ureido-¹?N]citrulline UPLC-MS/MS nitric oxide synthase (NOS) activity assay: development, validation, and applications to assess NOS uncoupling and human platelets NOS activity.

    PubMed

    Böhmer, Anke; Gambaryan, Stepan; Flentje, Markus; Jordan, Jens; Tsikas, Dimitrios

    2014-08-15

    In healthy human subjects, less than 0.2% of l-arginine is converted to l-citrulline and nitric oxide (NO) by NO synthases (NOS), a metabolic pathway present in all cell types. Assessment of NOS activity in vitro and in vivo by measuring l-citrulline or NO is difficult. l-citrulline is formed from l-arginine to a much higher extent by other pathways including the urea cycle. Furthermore, NO is a very short-lived gaseous molecule and is oxidized to nitrite and nitrate which are ubiquitous. In fact, nitrite and nitrate are also derived from food and air and are major laboratory contaminants. Further, NOS (in the uncoupled state) are also able to produce superoxide in addition and/or instead of l-citrulline and NO. The difficulties of NOS assays based on l-citrulline and NO measurement can only in part be overcome by sophisticated techniques including use of radio-labeled ((3)H or (14)C) and stable-isotope labeled ((15)N2 at the guanidine group) l-arginine analogs as substrates for NOS and measurement of radio-labeled l-citrulline and (15)N-labeled nitrite and nitrate, respectively. In the present work, we report on the development, validation and application of an UPLC-MS/MS method for the assessment of the activity of recombinant NOS enzymes by using [guanidino-(15)N2]-l-arginine (20 ?M for recombinant NOS, 5mM in cell systems) as the substrate and by measuring [ureido-(15)N]-l-citrulline as the reaction product (usually formed at concentrations below 1 ?M) using (2)H7-l-citrulline as the internal standard. The lower limit of detection of the method is about 80 fmol (2)H7-l-citrulline. In cell systems, exceeding [guanidino-(15)N2]-l-arginine is removed by strong cation exchanger solid-phase extraction. The method was cross-validated by a GC-MS assay that measures simultaneously (15)N-nitrite and (15)N-nitrate as pentafluorobenzyl derivatives, with unlabeled nitrite and nitrate serving as the internal standards. By means of this UPLC-MS/MS (15)N-citrulline assay, N(G)-nitro-arginine (100 ?M) was found to inhibit recombinant inducible NOS (iNOS) activity (by 38%), whereas nitrite and GSSG (each at 500 ?M) did not affect iNOS activity at all. Nitrite and GSSG at pathophysiological concentrations are unlikely to uncouple NOS. NOS activity was not detectable in platelets of healthy humans by the UPLC-MS/MS and GC-MS assays. PMID:25033468

  18. 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

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

    2010-01-01

    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

  19. Simultaneous determination of triamcinolone acetonide palmitate and triamcinolone acetonide in beagle dog plasma by UPLC-MS/MS and its application to a long-term pharmacokinetic study of triamcinolone acetonide palmitate lipid emulsion injection.

    PubMed

    Liu, Hui; Yang, Mingjing; Wu, Panpan; Guan, Jiao; Men, Lei; Lin, Hongli; Tang, Xing; Zhao, Yunli; Yu, Zhiguo

    2015-02-01

    In order to investigate the pharmacokinetics of triamcinolone acetonide palmitate (TAP) which is a lipid-soluble prodrug of triamcinolone acetonide (TA), a rapid, simple, sensitive and reproducible UPLC-MS/MS method has been developed and validated for the simultaneous determination of TAP and TA in beagle dog plasma. After simple liquid-liquid extraction, the analytes and internal standard (dexamethasone, DEX) were separated on Phenomenex Luna C18 column (50 mm × 2.1mm, 1.7 ?m) using a mobile phase consisting of solvent A (acetonitrile) and solvent B (0.1% ammonia solution) at a flow rate of 0.2 ml/min with gradient elution. Acquisition of mass spectrometric data was performed in multiple reaction monitoring (MRM) mode via positive electrospray ionization using the ion transitions of m/z 673.5?397.3, 435.3?415.3 and 393.3?355.3 for TAP, TA and IS, respectively. The method was of satisfactory specificity, sensitivity, precision and accuracy over the concentration range of 1-1,000 ng/ml for TAP and 0.5-500 ng/ml for TA. The intra- and inter-day precisions for both TAP and TA were 3.2% to 18.7% and the accuracy was in the range of -8.4% to 6.8%. The mean recoveries of TAP, TA and IS were 86.7-104.7%. The method was successfully applied to a long-term pharmacokinetic study of TAP and TA after 28-day repeated intravenous administration of TAP lipid emulsion injection to beagle dogs. PMID:25497892

  20. Pharmacokinetic comparisons by UPLC-MS/MS of isomer paeoniflorin and albiflorin after oral administration decoctions of single-herb Radix Paeoniae Alba and Zengmian Yiliu prescription to rats.

    PubMed

    Gong, Can; Yang, Hong; Wei, Hai; Qi, Cong; Wang, Chang-Hong

    2015-03-01

    Zengmian Yiliu (ZMYL), a traditional Chinese formula, is designed to improve clinical efficacy and reduce adverse effects in combination with cisplatin in ovarian cancer chemotherapy. In ZMYL, Radix Paeoniae Alba (RPA, made from root of Paeonia lactiflora Pall.) acts as an adjunctive drug in cancer treatment by ameliorating side effects induced by radio- and chemotherapy. The pharmacokinetics differences between isomer albiflorin and paeoniflorin, the main components of RPA, after oral administration decoction of single-herb RPA and ZMYL were compared using a sensitive and accurate UPLC-MS/MS. The results indicate that there are statistically significant differences between the pharmacokinetic parameters: decreasing area under the plasma concentration-time curve (AUC), maximum concentration (Cmax ), elimination rate constant (Ke ) and increasing apparent volume of distribution (Vd ) and clearance (CL) for albiflorin, increasing distribution half-life (T1/2d ) and decreasing elimination half-life (T1/2e ), distribution rate constant (Kd ) and absorption rate constant (Ka ) for paeoniflorin in the ZMYL group compared with the single-herb RPA group. In comparison with albiflorin, the pharmacokinetic parameters of paeoniflorin included significantly increasing mean residence time (MRT) and Vd , decreasing CL and Ke in the single-herb RPA group and increasing MRT and T1/2d and decreasing CL, Ke and Kd in the ZMYL group. Both paeoniflorin and albiflorin are more likely, as the main active ingredients in RPA and ZMYL, to play a variety of pharmacological effects, and herb-herb interactions occur, resulting in different pharmacokinetics of albiflorin and paeoniflorin in RPA and ZMYL. PMID:25042570

  1. Development and validation of a UPLC-MS/MS method for the determination of 7-hydroxymitragynine, a ?-opioid agonist, in rat plasma and its application to a pharmacokinetic study.

    PubMed

    Vuppala, Pradeep K; Jamalapuram, Seshulatha; Furr, Edward B; McCurdy, Christopher R; Avery, Bonnie A

    2013-12-01

    A simple, sensitive and specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated to determine the concentrations of 7-hydroxymitragynine in rat plasma. Following a single-step liquid-liquid extraction of plasma samples using chloroform, 7-hydroxymitragynine and the internal standard (tryptoline) were separated on an Acquity UPLC(TM) BEH C18 (1.7 µm, 2.1 × 50 mm) column using an isocratic elution at a flow rate of 0.2 mL/min. The mobile phase consisted of 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile (10:90, v/v). The run time was 2.5 min. The analysis was carried out under the multiple reaction-monitoring mode using positive electrospray ionization. Protonated ions [M + H](+) and their respective product ions were monitored at the following transitions: 415 ? 190 for 7-hydroxymitragynine and 173 ? 144 for the internal standard. The calibration curve was linear over the range of 10-4000 ng/mL (r(2) = 0.999) with a lower limit of quantification of 10 ng/mL. The extraction recoveries ranged from 62.0 to 67.3% at concentrations of 20, 600 and 3200?ng/mL). Intra- and inter-day assay precisions (relative standard deviation) were <15% and the accuracy was within 96.5-104.0%. This validated method was successfully applied to quantify 7-hydroxymitragynine in rat plasma following intravenous administration. PMID:23893615

  2. Development and validation of an UPLC-MS/MS method for the determination of 7-hydroxymitragynine, a ?-opioid agonist, in rat plasma and its application to a pharmacokinetic study

    PubMed Central

    Vuppala, Pradeep K.; Jamalapuram, Seshulatha; Furr, Edward B.; McCurdy, Christopher R.; Avery, Bonnie A.

    2014-01-01

    A simple, sensitive and specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method has been developed and validated to determine the concentrations of 7-hydroxymitragynine in rat plasma. Following a single step liquid-liquid extraction of plasma samples using chloroform, 7-hydroxymitragynine and the internal standard (tryptoline) were separated on an Acquity UPLC™ BEH C18 (1.7 ?m, 2.1 mm×50 mm) column using an isocratic elution at a flow rate of 0.2 mL/min. The mobile phase consisted of 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile (10:90, v/v). The run was 2.5 min. The analysis was carried out under the multiple reaction-monitoring mode using positive electrospray ionization. Protonated ions [M+H]+ and their respective product ions were monitored at the following transitions: 415>190 for 7-hydroxymitragynine and 173>144 for the internal standard. The calibration curve was linear over the range of 10 to 4000 ng/mL (r2=0.999) with a lower limit of quantification (LLOQ) of 10 ng/mL. The extraction recoveries ranged from 62.0% to 67.3% at concentrations (20, 600, 3200 ng/mL). Intra- and inter-day assay precisions (relative standard deviation) were less than 15% and the accuracy was within 96.5% to 104.0%. This validated method was successfully applied to quantify 7-hydroxymitragynine in rat plasma following intravenous administration. PMID:23893615

  3. Determination of Serotonin and Dopamine Metabolites in Human Brain Microdialysis and Cerebrospinal Fluid Samples by UPLC-MS/MS: Discovery of Intact Glucuronide and Sulfate Conjugates

    PubMed Central

    Suominen, Tina; Uutela, Päivi; Ketola, Raimo A.; Bergquist, Jonas; Hillered, Lars; Finel, Moshe; Zhang, Hongbo; Laakso, Aki; Kostiainen, Risto

    2013-01-01

    An UPLC-MS/MS method was developed for the determination of serotonin (5-HT), dopamine (DA), their phase I metabolites 5-HIAA, DOPAC and HVA, and their sulfate and glucuronide conjugates in human brain microdialysis samples obtained from two patients with acute brain injuries, ventricular cerebrospinal fluid (CSF) samples obtained from four patients with obstructive hydrocephalus, and a lumbar CSF sample pooled mainly from patients undergoing spinal anesthesia in preparation for orthopedic surgery. The method was validated by determining the limits of detection and quantification, linearity, repeatability and specificity. The direct method enabled the analysis of the intact phase II metabolites of 5-HT and DA, without hydrolysis of the conjugates. The method also enabled the analysis of the regioisomers of the conjugates, and several intact glucuronide and sulfate conjugates were identified and quantified for the first time in the human brain microdialysis and CSF samples. We were able to show the presence of 5-HIAA sulfate, and that dopamine-3-O-sulfate predominates over dopamine-4-O-sulfate in the human brain. The quantitative results suggest that sulfonation is a more important phase II metabolism pathway than glucuronidation in the human brain. PMID:23826355

  4. Development of a rapid UPLC-MS/MS method for quantification of saxagliptin in rat plasma and application to pharmacokinetic study.

    PubMed

    Gao, Jing-wen; Yuan, Yue-mei; Lu, Ya-song; Yao, Mei-cun

    2012-12-01

    A novel, simple and rapid ultraperformance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) assay was established for quantification of saxagliptin in rat plasma. Plasma samples were processed by liquid-liquid extraction with ethyl acetate and chromatographed on a C?? column (2.1?×?50?mm i.d., 1.7?µm). The mobile phase consisted of methanol and 0.1% formic acid (40:60, v/v). Multiple reaction monitoring transitions were performed for detection in positive-ion mode with an electrospray ionization source. The calibration curve was linear over the concentration range of 0.5-100?ng/mL (R² ?>?0.99). All accuracy values were between 90.62 and 105.60% relative error and the intra- and inter-day precisions were less than 9.66% relative standard deviation. Extraction recovery was more than 81.01% and the matrix effect ranged from 90.27 to 109.15%. After validation, the method was applied to a pharmacokinetic study where healthy rats were orally given 0.5?mg/kg saxagliptin. PMID:22334441

  5. 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...

  6. An UPLC-MS/MS method for the determination of valproic acid in blood of a fatal intoxication case.

    PubMed

    Proença, Paula; Franco, João Miguel; Mustra, Carla; Marcos, Mariana; Pereira, Ana Rita; Corte-Real, Francisco; Vieira, Duarte Nuno

    2011-10-01

    Valproic acid (VPA) has been used as an anticonvulsant for the treatment of epilepsy. The authors present a fatal case involving a 45-year-old female, found dead lying in bed with empty tablets of Diplexil(®) next to her. She was a chronic alcoholic and epileptic who had been under psychiatric treatment, having repeatedly demonstrated intent to commit suicide. A rapid method was developed and validated to determine VPA in blood by ultra-performance liquid chromatography (UPLC) coupled with tandem mass spectrometry (MS/MS) with electrospray ionization source in negative ion mode. The method involved sample treatment with phosphoric acid followed by solid-phase extraction. Chromatographic separation was achieved using an Acquity UPLC(®) BEH (2.1 × 50 mm id, 1.7 ?m) column and a mobile phase containing ammonium acetate and acetonitrile, at a 0.5 mL/min flow rate. Detection and quantification of VPA was achieved using multiple reaction monitoring (MRM). The MS/MS transitions used for monitoring were m/z 143.1-143.1 for valproic acid and m/z 296.1-205.0 for hydrochlorothiazide used as an internal standard (IS). The limit of quantification (LOQ) was 0.5 ?g/mL and the method was linear in the concentration range of 0.5-100 ?g/mL. The coefficients of variation obtained for accuracy and precision were less than 10% and the mean recovery was 95% for the three concentrations levels studied (5 ?g/mL, 10 ?g/mL and 50 ?g/mL). Toxicological results showed high concentration of VPA (556 ?g/mL) and therapeutic concentrations of tiapride, mirtazapine, oxazepam and nordiazepam. Blood sample analysis also revealed the presence of ethanol at a concentration of 1.34 g/L. A specific, selective and sensitive method for the determination of VPA in blood was developed and can be used in routine forensic investigation. Toxicological results led the pathologist to rule that death was due to an intoxication caused by the simultaneous ingestion of high VPA concentrations and alcohol, with a suicidal legal-medical etiology. PMID:21907937

  7. A rapid and accurate UPLC/MS/MS method for the simultaneous determination of zolpidem and its main metabolites in biological fluids and its application in a forensic context.

    PubMed

    Shi, Yan; Xiang, Ping; Shen, Baohua; Shen, Min

    2012-12-12

    Zolpidem (ZPD) is an imidazopyridine derivative used as a new type of hypnotic and is commonly used in drug-facilitated crimes. A rapid, sensitive, and specific ultra-performance liquid chromatography-tandem mass spectrometry (UPLC/MS/MS) assay method for the simultaneous determination of zolpidem and its main metabolites zolpidem 6-carboxylic acid (ZCA) and zolpidem phenyl-4-carboxylic acid (ZPCA) in biological fluids was developed and validated. Aliquots of 0.1mL blood or urine specimens were used for the analysis, and zolpidem and its metabolites were extracted in a single step using acetonitrile (containing 0.1% formic acid) precipitation. The supernatant was then dried, and 100?L methanol was added. The separation was performed on an Acquity™ UPLC HSS T3 (100mm×2.1mm, 1.8?m) analytical column by API 4000Q ultra-performance liquid chromatography-tandem mass spectrometry. Positive ionisation tandem MS detection in the multiple reaction monitoring (MRM) mode was used. The mobile phases consisted of either acetonitrile or water containing 20mmol/L ammonium acetate and 0.1% formic acid, and the flow rate was 0.5mL/min. The chromatographic separation time was 4min, and calibration curves for human blood were generated over the range of 0.1-300ng/mL for ZPD, 0.1-500ng/mL for ZPCA and 0.1-200ng/mL for ZCA. For urine, the linear range was 0.1-600ng/mL for ZPD and ZPCA, and 0.1-300ng/mL for ZCA. The limit of detection was 0.05ng/mL and the limit of quantitation was 0.1ng/mL for ZPD, ZCA and ZPCA. The linear correlation coefficients were greater than 0.9995. Both the inter-day and intra-day precisions were less than 15%, the recoveries were in the range of 70.0-98.3%, the matrix effects were approximately 79.5-99.0%, and the process efficiency was between 60.7% and 94.4%. This method allowed for the determination of zolpidem and its metabolites in human blood and urine and may be applied to forensic toxicological analyses. PMID:23217317

  8. 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

    Simões, Susana Sadler; Silva, Inês; Ajenjo, Antonio Castañera; Dias, Mário João

    2014-10-01

    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 (50mm×2.1mm 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

  9. Antioxidant properties and quantitative UPLC-MS analysis of phenolic compounds from extracts of fenugreek (Trigonella foenum-graecum) seeds and bitter melon (Momordica charantia) fruit.

    PubMed

    Kenny, O; Smyth, T J; Hewage, C M; Brunton, N P

    2013-12-15

    Freeze-dried fenugreek (Trigonella foenum-graecum) seeds and bitter melon (Momordica charantia) fruit were extracted sequentially using non-polar to polar solvents, with further separation carried out on polar extracts by molecular weight cut off dialysis. The fenugreek ethyl acetate crude extract (FGE3) demonstrated the highest antioxidant activity, in terms of Trolox Equivalents (TE), for both the DPPH (35.338±0.908 mg TE/g) and FRAP (77.352±0.627 mg TE/g) assays. This extract also contained the highest phenolic content, in terms of Gallic Acid Equivalents (GAE) (106.316±0.377 mg GAE/g). Despite having considerably lower antioxidant activity than fenugreek, the highest antioxidant activities for bitter fruit were observed in the hexane (BME1) and methanol hydrophilic<3.5 kDa dialysed (BME4<3.5 kDa) extracts, while the highest phenolic content was found in the methanol hydrophilic>3.5 kDa (BME4>3.5 kDa) dialysed extract. UPLC-MS was used to quantify 18 phenolic compounds from fenugreek and 13 from bitter melon in active crude extracts. The flavonoids apigenin-7-O-glycoside (1955.55 ng/mg) and luteolin-7-O-glycoside (725.50 ng/mg) were the most abundant compounds in FGE3, while bitter melon extracts contained only small amounts of mainly phenolic acids. A further 5 fenugreek and 1 bitter melon compounds were identified in trace amounts from the same extracts, respectively. PMID:23993618

  10. UPLC-MS-ELSD-PDA as a powerful dereplication tool to facilitate compound identification from small molecule natural product libraries

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Generation of natural product libraries containing column fractions, each with only a few small molecules, by a high throughput, automated fractionation system has made it possible to implement an improved dereplication strategy for selection and prioritization of hits in a natural product discovery...

  11. Simultaneous determination of xylazine, free morphine, codeine, 6-acetylmorphine, cocaine and benzoylecgonine in postmortem blood by UPLC-MS-MS.

    PubMed

    Ruiz-Colón, Kazandra; Martínez, María A; Silva-Torres, Luz A; Chavez-Arias, Carlos; Meléndez-Negrón, Margarita; Conte-Miller, María S; Bloom-Oquendo, Joseph

    2012-06-01

    Xylazine, a veterinary sedative, has been found as an adulterant of heroin in street drugs in Puerto Rico. It was found in combination with free morphine and 6-acetylmorphine, codeine, cocaine and benzoylecgonine in postmortem cases at the Puerto Rico Institute of Forensic Sciences (PRIFS). Xylazine is not approved for human use because it has been proven harmful. Currently, three separate analyses are required to determine all the aforementioned drugs at the PRIFS's toxicology laboratory. To reduce analysis time consumption, sample volume, run time, sample preparation and cost, a high-throughput ultra-high-pressure liquid chromatography-tandem mass spectrometry method was developed and validated for the simultaneous quantification of xylazine, free morphine, 6-acetylmorphine, codeine, cocaine and benzoylecgonine in 0.25 mL postmortem blood by protein precipitation, fulfilling confirmation criteria with three transitions for each compound with acceptable relative ion intensities. Linearity was established between 10-1,000 ng/mL. Total run time was 2.5 min. Limit of detection was 1 ng/mL for cocaine and xylazine, 2 ng/mL for 6-acetylmorphine and 10 ng/mL for free morphine, codeine and benzoylecgonine. The intra-day and inter-day precision and accuracy was less than 15.6%. Process efficiencies ranged from 35.9 to 123.4% and recoveries from 59.9 to 110.1%. The developed method was successfully applied to casework. PMID:22582266

  12. Assessment of nicotine for second hand smoke exposure in some public places in Romania by UPLC-MS

    PubMed Central

    2014-01-01

    Background Air nicotine monitoring is a well-known procedure for estimation of exposure to second hand smoke. Few research studies were realized in Romania to evaluate environmental tobacco smoke (ETS) exposure of humans in different public places. The levels of airborne nicotine from environmental tobacco smoke and urinary cotinine and nicotine levels of some subjects were analyzed. In order to better implement/enforce the European legislation regarding the interdiction of smoking in the public places the national authorities need a rapid and reliable analytical method to quickly asses the state of the pollution with cigarette smoke of these populated areas. Results The nicotine concentration in the air from different types of public buildings was determined. The median concentration of nicotine in the air from 32 pubs where the smoking was allowed was 590 ng?·?L-1, comparing with the pubs where the smoking was not permitted (22 locations) where the median concentration of nicotine was only 32 ng?·?L-1. Similarly, the median concentration of nicotine in restaurants where the smoking was allowed (23 locations) was 510 ng?·?L-1, in comparison with the restaurants where the smoking was prohibited (11 places) where the median value was 19 ng?·?L-1. The lowest concentrations of nicotine were found in high schools (8 locations, median concentration 7.4 ng?·?L-1), universities (5 locations, 23 ng?·?L-1) and hospitals (6 locations, 16 ng?·?L-1). Conclusions The method was validated and gave good linearity, precision, accuracy and limit of detection. The buildings included hospitals, high schools, universities, pubs and restaurants. The presence of air nicotine was recorded in all buildings studied. The highest median levels of air nicotine were found in pubs and restaurants. The presence of air nicotine in indoor public buildings indicates weak implementation of the smoke free law in Romania. PMID:24839459

  13. Determination of benzodiazepines in ante-mortem and post-mortem whole blood by solid-supported liquid-liquid extraction and UPLC-MS/MS.

    PubMed

    Sauve, E N; Langødegård, M; Ekeberg, D; Øiestad, A M L

    2012-02-01

    A solid-supported liquid-liquid extraction ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed and validated for the determination of benzodiazepines commonly found in Norway, for use in cases with suspected driving impairment and autopsy cases by analysis of human whole blood samples. The following compounds were included: alprazolam, bromazepam, clonazepam, diazepam, flunitrazepam, lorazepam, midazolam, nitrazepam, nordiazepam (metabolite of diazepam), oxazepam and phenazepam. Aliquots of 500 ?L whole blood were added 500 ?L of borate buffer pH 11 and extracted by solid-supported liquid-liquid extraction on ChemElut(®) columns using three times 2.5 mL of methyl tert-butyl ether. Deuterated analogues were used as internal standards (IS) for all analytes, except for midazolam, phenazepam and bromazepam which had no commercially available deuterated analogues at the time the method was developed, and therefore used diazepam-d(5), flunitrazepam-d(7) and nitrazepam-d(5), respectively. The analytes were separated using UPLC with a 2.1×100 mm BEH C(18)-column, 1.7 ?m particle size, and quantified by MS/MS using multiple reaction monitoring (MRM) in positive mode. Two transitions were used for the analytes and one transition for the IS. The run time of the method was 8 min including equilibration time. The concentrations of the benzodiazepines in the method span a broad range varying from the lowest concentration of 0.005 ?M for flunitrazepam to the highest of 20 ?M for oxazepam. The calibration curves of extracted whole blood standards were fitted by second-order calibration curves weighted 1/x, with R(2) values ranging from 0.9981 to 0.9998. The intermediate precision had a CV (%) ranging between 2 and 19%. Recoveries of the analytes were from 71 to 96%. The LLOQs for the analytes varied from 0.0006 to 0.075 ?M and the LODs from 0.005 to 3.0 nM. Matrix effects were studied by post extraction addition and found to be between 95 and 104% when calculated against an internal standard. A comparison with two other LC-MS methods was performed during method validation. Good correlation was seen for all analytes. The method has been running on a routine basis for several years, and has proven to be very robust and reliable with good results for external quality samples. The method also meets the requirements of the legislative limits for driving under the influence of non-alcohol drugs to be introduced in the Norwegian legislative system from 2012. PMID:22119506

  14. Development of a sensitive and selective liquid chromatography-mass spectrometry method for high throughput analysis of paralytic shellfish toxins using graphitised carbon solid phase extraction.

    PubMed

    Boundy, Michael J; Selwood, Andrew I; Harwood, D Tim; McNabb, Paul S; Turner, Andrew D

    2015-03-27

    Routine regulatory monitoring of paralytic shellfish toxins (PST) commonly employs oxidative derivitisation and complex liquid chromatography fluorescence detection methods (LC-FL). The pre-column oxidation LC-FL method is currently implemented in New Zealand and the United Kingdom. When using this method positive samples are fractionated and two different oxidations are required to confirm the identity and quantity of each PST analogue present. There is a need for alternative methods that are simpler, provide faster turnaround times and have improved detection limits. Hydrophilic interaction liquid chromatography (HILIC) HPLC-MS/MS analysis of PST has been used for research purposes, but high detection limits and substantial sample matrix issues have prevented it from becoming a viable alternative for routine monitoring purposes. We have developed a HILIC UPLC-MS/MS method for paralytic shellfish toxins with an optimised desalting clean-up procedure on inexpensive carbon solid phase extraction cartridges for reduction of matrix interferences. This represents a major technical breakthrough and allows sensitive, selective and rapid analysis of paralytic shellfish toxins from a variety of sample types, including many commercially produced bivalve molluscan shellfish species. Additionally, this analytical approach avoids the need for complex calculations to determine sample toxicity, as unlike other methods each PST analogue is able to be quantified as a single resolved peak. This article presents the method development and optimisation information. A thorough single laboratory validation study has subsequently been performed and this data will be presented elsewhere. PMID:25704772

  15. A novel method for high throughput lipophilicity determination by microscale shake flask and liquid chromatography tandem mass spectrometry.

    PubMed

    Lin, Baiwei; Pease, Joseph H

    2013-12-01

    Modern small molecule drug design requires the optimization of not only the binding characteristics of the molecule but also its physicochemical properties for ADMET performance. A key physical property is lipophilicity and medicinal chemists need rapid access to high quality data in order to drive their decision making. Traditionally lipophilicity (log D) measurements are performed with a shake flask method and UV determination. This method suffers from low sensitivity and is not easily converted to a high throughput format. Over the past decade, several groups have taken different approaches to improve this assay, including replacing the shake flask method with one that utilizes reverse phase HPLC. Here we describe a new microscale shake flask method that utilizes UPLC-MS/MS to achieve increased throughput, sensitivity and accuracy. Approaches for assessing data quality are also described. This platform technology only requires micrograms of compound and is routinely used by most small molecule drug discovery project teams at Genentech. PMID:24168238

  16. A UPLC–MS\\/MS application for profiling of intermediary energy metabolites in microdialysis samples—A method for high-throughput

    Microsoft Academic Search

    Rune Isak Dupont Birkler; Nicolaj Brejnholt Støttrup; Sigurd Hermannson; Torsten Toftegaard Nielsen; Niels Gregersen; Hans Erik Bøtker; Mette Findal Andreasen; Mogens Johannsen

    2010-01-01

    Research within the field of metabolite profiling has already illuminated our understanding of a variety of physiological and pathological processes. Microdialysis has added further refinement to previous models and has allowed the testing of new hypotheses. In the present study, a new ultra-performance liquid chromatography\\/electrospray-tandem mass spectrometry (UPLC-ESI-MS\\/MS) method for the simultaneous detection and quantification of intermediary energy metabolites in

  17. Rapid screening of mycotoxins in liquid milk and milk powder by automated size-exclusion SPE-UPLC-MS/MS and quantification of matrix effects over the whole chromatographic run.

    PubMed

    Wang, Xiupin; Li, Peiwu

    2015-04-15

    An automated, size-exclusion solid phase extraction (SPE)-UPLC-MS/MS protocol without pre-treatment of samples was developed to screen for four mycotoxins (OTA, ZEN, AFB1, and AFM1) in liquid milk and milk powder. Firstly, a mixed macropore-silica gel cartridge was established as a size-exclusion SPE column. The proposed methodology could be a candidate in green analytical chemistry because it saves on manpower and organic solvent. Permanent post-column infusion of mycotoxin standards was used to quantify matrix effects throughout the chromatographic run. Matrix-matched calibration could effectively compensate for matrix effects, which may be caused by liquid milk or milk powder matrix. Recovery of the four mycotoxins in fortified liquid milk was in the range 89-120% and RSD 2-9%. The LOD for the four mycotoxins in liquid milk and milk powder were 0.05-2 ng L(-1) and 0.25-10 ng kg(-1), respectively. The LOQ for the four mycotoxins in liquid milk and milk powder were 0.1-5 ng L(-1) and 0.5-25 ng kg(-1), respectively. PMID:25466104

  18. Validation of Simultaneous Quantitative Method of HIV Protease Inhibitors Atazanavir, Darunavir and Ritonavir in Human Plasma by UPLC-MS/MS

    PubMed Central

    Mishra, Tulsidas; Shrivastav, Pranav S.

    2014-01-01

    Objectives. HIV protease inhibitors are used in the treatment of patients suffering from AIDS and they act at the final stage of viral replication by interfering with the HIV protease enzyme. The paper describes a selective, sensitive, and robust method for simultaneous determination of three protease inhibitors atazanavir, darunavir and ritonavir in human plasma by ultra performance liquid chromatography-tandem mass spectrometry. Materials and Methods. The sample pretreatment consisted of solid phase extraction of analytes and their deuterated analogs as internal standards from 50??L human plasma. Chromatographic separation of analytes was performed on Waters Acquity UPLC C18 (50 × 2.1?mm, 1.7??m) column under gradient conditions using 10?mM ammonium formate, pH 4.0, and acetonitrile as the mobile phase. Results. The method was established over a concentration range of 5.0–6000?ng/mL for atazanavir, 5.0–5000?ng/mL for darunavir and 1.0–500?ng/mL for ritonavir. Accuracy, precision, matrix effect, recovery, and stability of the analytes were evaluated as per US FDA guidelines. Conclusions. The efficiency of sample preparation, short analysis time, and high selectivity permit simultaneous estimation of these inhibitors. The validated method can be useful in determining plasma concentration of these protease inhibitors for therapeutic drug monitoring and in high throughput clinical studies. PMID:24587725

  19. High specific monoclonal antibody production and development of an ELISA method for monitoring T-2 toxin in rice.

    PubMed

    Li, Yanshen; Luo, Xiangshu; Yang, Shupeng; Cao, Xingyuan; Wang, Zhanhui; Shi, Weimin; Zhang, Suxia

    2014-02-19

    This research produced a highly-specific and sensitive anti-T-2 toxin monoclonal antibody (mAb), and developed a rapid and sensitive competitive indirect enzyme-linked immunosorbent assay (ELISA) method for monitoring T-2 toxin in rice. The mAb showed a negligible cross-reactivity value (CR) to most of the mycotoxins, and it could specifically bind to T-2 toxin without other mycotoxins, including HT-2 toxin (CR value at 3.08%), which exhibited a similar structure to T-2 toxin. The limit of detection (LOD) value, measured by IC10, was 5.80 ?g/kg. In spiked samples, mean recoveries ranged from 72.0% to 108.5% with intraday and interday variation less than 16.8 and 13.7%. This proposed protocol was significantly confirmed by a reliable ultrahigh performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method and significant correlation was obtained. PMID:24450660

  20. Metabonomic analysis of urine from rats after low-dose exposure to 3-chloro-1,2-propanediol using UPLC-MS.

    PubMed

    Liu, Liyan; He, Yujie; Lu, Huimin; Wang, Maoqing; Sun, Changhao; Na, Lixin; Li, Ying

    2013-05-15

    To study the toxic effect of chronic exposure to 3-chloro-1,2-propanediol (3-MCPD) at low doses, a metabonomics approach based on ultrahigh-performance liquid chromatography and quadruple time-of-flight mass spectrometry (UPLC-Q-TOF-MS) was performed. Two different doses of 3-MCPD (1.1 and 5.5mg/kg bw/d) were administered to Wistar rats for 120 days (1.1mg/kg bw/d: lowest observed adverse effect level [LOAEL]). The metabolite profiles and biochemical parameters were obtained at five time points after treatment. For the 3-MCPD-treated groups, a significant change in urinary N-acetyl-?-d-glucosaminidase and ?-d-galactosidase was detected on day 90, while some biomarkers based on the metabonomics, such as N-acetylneuraminic acid, N-acetyl-l-tyrosine, and gulonic acid, were detected on day 30. These results suggest that these biomarkers changed more sensitively and earlier than conventional biochemical parameters and were thus considered early and sensitive biomarkers of exposure to 3-MCPD; these biomarkers provide more information on toxicity than conventional biochemical parameters. These results might be helpful to investigate the toxic mechanisms of 3-MCPD and provide a scientific basis for assessing the effect of chronic exposure to low-dose 3-MCPD on human health. PMID:23522902

  1. Simultaneous determination of seven taxoids in rat plasma by UPLC-MS/MS and pharmacokinetic study after oral administration of Taxus yunnanensis extracts.

    PubMed

    Liu, Bin; Gou, Xiaoli; Bai, Xupeng; Hou, Xiangyu; Li, Dongshun; Zhong, Guoping; Jin, Jing; Huang, Min

    2015-03-25

    A rapid, sensitive and reliable method has been developed and validated for the simultaneous determination of seven taxoids including 10-deacetylbaccatin III (10-DAB III), baccatin III, 5-epi-canadensene, taxinine M, 10-deacetyltaxol (10-DAT), cephalomannine and paclitaxel in rat plasma using docetaxel as the internal standard (IS). The plasma samples were pretreated by liquid-liquid extraction with methyl tert-butyl ether. The chromatographic separation was achieved on a C18 column (50mm×2.1mm, 1.8?m, Waters, USA) with a gradient elution program consisting of methanol and water (containing 0.1% formic acid) at a flow rate of 0.2mL/min. Detection was performed under the selected reaction monitoring (SRM) scan using an electrospray ionization (ESI) in the positive ion mode. The mass transitions were as follows: m/z 567.4?444.9 for 10-DAB III, m/z 609.0?549.3 for baccatin III, m/z 617.4?496.9 for 5-epi-canadensene, m/z 709.6?649.3 for taxinine M, m/z 834.8?307.9 for 10-DAT, m/z 854.5?285.4 for cephalomannine, m/z 876.8?307.3 for paclitaxel and m/z 830.8?549.6 for IS, respectively. All calibration curves exhibited good linearity (r(2)>0.99) over a wide concentration range for all components. The intra-day and inter-day precisions at three different levels were both less than 14.3% in terms of relative standard deviation (RSD) and the accuracies ranged from -8.3% to 14.8% in terms of relative error (RE). The extraction recoveries of the seven compounds ranged from 62.5% to 100.5%. The developed method was successfully applied to the pharmacokinetic study of the seven taxoids in rat plasma after oral administration of the crude extract of the twigs and leaves of Taxus yunnanensis. PMID:25645339

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

    PubMed

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

    2013-12-01

    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

  3. Objective set of criteria for optimization of sample preparation procedures for ultra-high throughput untargeted blood plasma lipid profiling by ultra performance liquid chromatography-mass spectrometry.

    PubMed

    Sarafian, Magali H; Gaudin, Mathieu; Lewis, Matthew R; Martin, Francois-Pierre; Holmes, Elaine; Nicholson, Jeremy K; Dumas, Marc-Emmanuel

    2014-06-17

    Exploratory or untargeted ultra performance liquid chromatography-mass spectrometry (UPLC-MS) profiling offers an overview of the complex lipid species diversity present in blood plasma. Here, we evaluate and compare eight sample preparation protocols for optimized blood plasma lipid extraction and measurement by UPLC-MS lipid profiling, including four protein precipitation methods (i.e., methanol, acetonitrile, isopropanol, and isopropanol-acetonitrile) and four liquid-liquid extractions (i.e., methanol combined with chloroform, dichloromethane, and methyl-tert butyl ether and isopropanol with hexane). The eight methods were then benchmarked using a set of qualitative and quantitative criteria selected to warrant compliance with high-throughput analytical workflows: protein removal efficiency, selectivity, repeatability, and recovery efficiency of the sample preparation. We found that protein removal was more efficient by precipitation (99%) than extraction (95%). Additionally, isopropanol appeared to be the most straightforward and robust solvent (61.1% of features with coefficient of variation (CV) < 20%) while enabling a broad coverage and recovery of plasma lipid species. These results demonstrate that isopropanol precipitation is an excellent sample preparation procedure for high-throughput untargeted lipid profiling using UPLC-MS. Isopropanol precipitation is not limited to untargeted profiling and could also be of interest for targeted UPLC-MS/MS lipid analysis. Collectively, these data show that lipid profiling greatly benefits from an isopropanol precipitation in terms of simplicity, protein removal efficiency, repeatability, lipid recovery, and coverage. PMID:24820162

  4. Wipe selection for the analysis of surface materials containing chemical warfare agent nitrogen mustard degradation products by ultra-high pressure liquid chromatography-tandem mass spectrometry.

    PubMed

    Willison, Stuart A

    2012-12-28

    Degradation products arising from nitrogen mustard chemical warfare agent were deposited on common urban surfaces and determined via surface wiping, wipe extraction, and liquid chromatography–tandem mass spectrometry detection. Wipes investigated included cotton gauze, glass fiber filter, non-woven polyester fiber and filter paper, and surfaces included several porous (vinyl tile, painted drywall, wood) and mostly non-porous (laminate, galvanized steel, glass) surfaces. Wipe extracts were analyzed by ultra-high pressure liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) and compared with high performance liquid chromatography–tandem mass spectrometry (HPLC–MS/MS) results. An evaluation of both techniques suggests UPLC–MS/MS provides a quick and sensitive analysis of targeted degradation products in addition to being nearly four times faster than a single HPLC run, allowing for greater throughput during a wide-spread release concerning large-scale contamination and subsequent remediation events. Based on the overall performance of all tested wipes, filter paper wipes were selected over other wipes because they did not contain interferences or native species (TEA and DEA) associated with the target analytes, resulting in high percent recoveries and low background levels during sample analysis. Other wipes, including cotton gauze, would require a pre-cleaning step due to the presence of large quantities of native species or interferences of the targeted analytes. Percent recoveries obtained from a laminate surface were 47–99% for all nitrogen mustard degradation products. The resulting detection limits achieved from wipes were 0.2 ng/cm(2) for triethanolamine (TEA), 0.03 ng/cm(2) for N-ethyldiethanolamine (EDEA), 0.1 ng/cm(2) for N-methyldiethanolamine (MDEA), and 0.1 ng/cm(2) for diethanolamine (DEA). PMID:23218189

  5. Highly sensitive integrated optical biosensors

    NASA Astrophysics Data System (ADS)

    Zamora, Vanessa; Lützow, Peter; Weiland, Martin; Pergande, Daniel; Schröder, Henning

    2014-03-01

    Optical sensor systems for biological and medical applications have been widely developed in order to satisfy the current requirements such as a miniaturization, cost reduction, label-free detection and fast response. Here, we demonstrate a highly sensitive optical sensor based on two cascaded microring resonators (MRRs) exploiting the Vernier effect. The architecture consists of a filter MRR connected to a sensor MRR via a common waveguide. The external medium of the filter MRR is isolated with a top cladding layer, while the sensor MRR interacts with the analyte sample via an opening. The sensor chip, that includes an array of five cascaded MRRs, was designed and fabricated on a silicon nitride platform. A first test has been performed with sodium chloride (NaCl) concentrations in deionized (DI) water providing a sensitivity of 1.03 nm/% (6317 nm/RIU). A limit of detection of 3.16 x 10-6 RIU was demonstrated for the current sensor, respectively. Several concentrations of isopropanol in ethanol ranging from 0% to 10% were also investigated. These preliminary measurements show a sensitivity as high as 0.95 nm/% at ~1535 nm compared to 0.02 nm/% from a single sensor MRR. For a moderated alignment between the chip and cleaved optical fibers, tapered grating couplers are included at the ends of waveguides. Hence, by combining the Vernier effect and the silicon nitride material, cascaded MRRs will be a powerful optical configuration for biosensing applications in a wide operating wavelength range.

  6. A high sensitivity THz detector

    NASA Astrophysics Data System (ADS)

    Su, Bo; Duan, Guoteng

    2011-08-01

    We have developed a novel THz detector which uses the cantilever technology and surface plasmon resonance (SPR) technology to achieve a high sensitivity. The Micro Electro Mechanical System (MEMS) technology is adopted to fabricate the detector, which comprise thermo-sensitive bi-material micro-cantilever, prism and optical readout system. The bi-material of Si3N4 and Al is used to fabricate the micro-cantilever because of the good absorption characteristic for THz of Si3N4 and the great difference in thermal expansion coefficient of the bi-material for the deformation of the micro-cantilever. In order to increase the deformation of micro-cantilever, the method of computer simulation is used to obtain the optimal structure of micro-cantilever and the thickness of Si3N4 and Al. The function of the glass prism is to make the incident light generate total reflection under certain conditions. The gold film is sputtering on the top of glass slide using the method of magnetron sputtering and it is necessary for the generation of SPR performance. The optical readout system can make the change of cantilever bending convert to the change of reflection luminous intensity proportionally. The heat on the micro-cantilever coming from the THz radiation can lose easily in the air, so the detector is placed vertically in a cylindrical vacuum chamber which is sealed with quartz glasses and polyethylene lamina at the two end surfaces respectively. The quartz glass is used for the incidence of visible polarized light and the polyethylene lamina for the THz radiation. In order to maintain the vacuum performance of the chamber, the mechanical pump and molecular pump are adopted. In static mode, THz radiation absorption raises the temperature of micro-cantilever, so it bends proportionally. The micro-cantilever bending changes the thicknesses of the gap between the micro-cantilever and the metallic thin film on the micro-prism. It will result in a shift of the SPR angle. Therefore, the surface plasmon excitation efficiency and therewith the measured at a fixed incident angle reflectance of a metallic film will be changed almost proportionally to the cantilever bending. Consequently, the radiation energy of THz can be determined via the metallic film reflectivity change. Finally, the technology of image processing is introduced in detail.

  7. Simultaneous Determination of 11 ?-Agonists in Human Urine Using High-Performance Liquid Chromatography/Tandem Mass Spectrometry with Isotope Dilution.

    PubMed

    Wang, Xiaoli; Guo, Tao; Wang, Shanshan; Yuan, Jinpeng; Zhao, Rusong

    2015-04-01

    The misuse of ?-agonists constitutes a potential risk to public health and has been forbidden in many countries. In this study, we describe a method for specific, sensitive and rapid detection of ?-agonists in human urine. Urine samples were extracted with ethyl acetate, without any additional purification step, and analyzed by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS) with Clenbuterol-D9 and Salbuterol-D3 as internal standards. The intra- and interday precision values of the method were all <5.60% and the accuracy ranged from 94.5 to 109%. Extraction recovery for 11 ?-agonists varied from 66.7 to 108%. One UPLC-MS-MS analysis could be completed within 12 min and the limits of detection for 11 ?-agonists were 0.1 ng/mL in the experiment. ?-Agonists in human urines from 24 volunteers were analyzed by our validated method and 1.70 ng/mL salbutamol was detected in one volunteer. The application of UPLC-MS-MS method in ?-agonists detection of human urine will be helpful in veterinary control of ?-agonists and for studying the effect of ?-agonists on human health. PMID:25542892

  8. Fast, high sensitivity dewpoint hygrometer

    NASA Technical Reports Server (NTRS)

    Hoenk, Michael E. (Inventor)

    1998-01-01

    A dewpoint/frostpoint hygrometer that uses a surface moisture-sensitive sensor as part of an RF oscillator circuit with feedback control of the sensor temperature to maintain equilibrium at the sensor surface between ambient water vapor and condensed water/ice. The invention is preferably implemented using a surface acoustic wave (SAW) device in an RF oscillator circuit configured to generate a condensation-dependent output signal, a temperature sensor to measure the temperature of the SAW device and to distinguish between condensation-dependent and temperature-dependent signals, a temperature regulating device to control the temperature of the SAW device, and a feedback control system configured to keep the condensation-dependent signal nearly constant over time in the presence of time-varying humidity, corrected for temperature. The effect of this response is to heat or cool the surface moisture-sensitive device, which shifts the equilibrium with respect to evaporation and condensation at the surface of the device. The equilibrium temperature under feedback control is a measure of dewpoint or frostpoint.

  9. Cryogenic High-Sensitivity Magnetometer

    NASA Technical Reports Server (NTRS)

    Day, Peter; Chui, Talso; Goodstein, David

    2005-01-01

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

  10. Modulated high sensitivity infrared polarimeter

    NASA Astrophysics Data System (ADS)

    Grisham, John A.; Clarke, Frederick W.; Christensen, Charles R.; Stenby, John L.

    1992-02-01

    A modulated Faraday rotation signal is produced by passing a linearly polarized laser beam through a semiconductor wafer sample in a modulated magnetic field that is induced in a electromagnet by a sine wave generator and driver coupled thereto. The rotation signal is normalized by dividing by a transmission signal produced by modulating the beam with a chopper that operates at a different frequency from the frequency of the driver. The result is a Faraday rotation measurement with high signal-to-noise ratio and compensation for laser drift in intensity and beam direction.

  11. High-speed and high-sensitive optical coherence angiography

    NASA Astrophysics Data System (ADS)

    Makita, Shuichi; Yamanari, Masahiro; Yasuno, Yoshiaki

    2009-07-01

    High-speed and high-sensitive phase-resolved spectral-domain optical coherence tomography has been developed. Two tomograms with a time separation have been acquired with dual beams. High-sensitive Doppler optical coherence angiography of the human eye has been demonstrated.

  12. Simultaneous determination of mosapride and its active des-p-fluorobenzyl and 4'-N-oxide metabolites in rat plasma using UPLC-MS/MS: An application for a pharmacokinetic study.

    PubMed

    Zhao, Longshan; Sun, Xiaohong; Xiong, Zhili; Wang, Shaojie

    2015-05-01

    An efficient and sensitive ultra-performance chromatography-tandem mass spectrometry method to simultaneously determinate and quantify mosapride (M) and its des-p-fluorobenzyl (M1) and 4'-N-oxide (M2) metabolites using carbamazepine as the internal standard (IS) in rat plasma has been developed and validated. Analytes were extracted from aliquots of plasma with ethyl acetate after alkalization using saturated sodium carbonate solution. The chromatographic separation was conducted on a BEH C18 column (100mm×2.1mm, 1.7?m) with the gradient elution using a mobile phase of acetonitrile - 0.2% formic acid in water at a flow rate of 0.25mL/min for 4min. The tandem mass spectrometric detection was conducted using multiple reaction monitoring (MRM) by the positive electrospray ionization (ESI). The ion transitions monitored were m/z 422?198 for mosapride, m/z 314?198 for M1, m/z 438?109 for M2 and m/z 237?194 for IS. The linear ranges of the calibration curves were 1.0-2000ng/mL for M, 0.75-1875ng/mL for M1 and 0.4-40ng/mL for M2. And the corresponding lower limits of quantitation (LLOQ) of the method were 1.0, 0.75, 0.4ng/mL for M, M1 and M2, respectively. The intra- and inter-day precision for all analytes were less than 8.1% and 11.6%, respectively. The inter-assay mean accuracy was between -6.4% and 8.1%. No relevant cross-talk and matrix effect were observed. There were significant differences between male and female rats for M, M1 and M2. PMID:25770615

  13. 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

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

    2014-01-01

    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

  14. High Sensitivity deflection detection of nanowires

    SciTech Connect

    Sanii, Babak; Ashby, Paul

    2009-10-28

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

  15. Metabolomic serum profiling detects early-stage high-grade serous ovarian cancer in a mouse model.

    PubMed

    Jones, Christina M; Monge, María Eugenia; Kim, Jaeyeon; Matzuk, Martin M; Fernández, Facundo M

    2015-02-01

    Ovarian cancer is a deadly disease killing more than any other gynecologic cancer. Nonspecific symptoms, combined with a lack of early detection methods, contribute to late diagnosis and low five-year survival rates. High-grade serous carcinoma (HGSC) is the most common and deadliest subtype that results in 90% of ovarian cancer deaths. To investigate metabolic patterns for early detection of this deadly ovarian cancer, Dicer-Pten double knockout (DKO) mice that phenocopy many of the features of metastatic HGSC observed in women were studied. Using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS), serum samples from 14 early-stage tumor (ET) DKO mice and 11 controls were analyzed in depth to screen for metabolic signatures capable of differentiating early-stage HGSC from controls. Iterative multivariate classification selected 18 metabolites that, when considered as a panel, yielded 100% accuracy, sensitivity, and specificity for classification. Altered metabolic pathways reflected in that panel included those of fatty acids, bile acids, glycerophospholipids, peptides, and some dietary phytochemicals. These alterations revealed impacts to cellular energy storage and membrane stability, as well as changes in defenses against oxidative stress, shedding new light on the metabolic alterations associated with early ovarian cancer stages. PMID:25567202

  16. Highly sensitive beam steering with plasmonic antenna

    NASA Astrophysics Data System (ADS)

    Rui, Guanghao; Zhan, Qiwen

    2014-08-01

    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.

  17. Highly sensitive beam steering with plasmonic antenna.

    PubMed

    Rui, Guanghao; Zhan, Qiwen

    2014-01-01

    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. PMID:25091405

  18. High sensitive method for optical birefringence measurement

    NASA Astrophysics Data System (ADS)

    Kunc, S.; Šulc, M.

    2015-01-01

    A sensitive method for optical birefringence measurement is presented. To optimize the signal over the noise ratio, the polarization of the laser beam is modulated exceptionally with a high frequency electro-optical modulator. The specially developed optical apparatus exhibits high sensitivity and accuracy, which were checked by measuring the Cotton-Mouton effect in nitrogen as a function of the pressure. It is able to measure the retardance down to 2x10-4 rad. This apparatus will be used with the locked optical cavity. The optical cavity will serve as an optical path multiplier for increasing the sensitivity. This proposed set-up will be able to measure the Cotton-Mouton effect in helium, where the birefringence effect is ?n ? 2.4x10-16.

  19. Highly sensitive beam steering with plasmonic antenna

    PubMed Central

    Rui, Guanghao; Zhan, Qiwen

    2014-01-01

    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. PMID:25091405

  20. High-sensitivity bunch charge monitor

    NASA Astrophysics Data System (ADS)

    Lebedev, N. I.; Fateev, A. A.

    2008-12-01

    The conceptual design for a high-sensitivity bunch charge monitor is presented. The device operates with short, spaced bunches. For optimal performance, the bunch duration should be less than 10 ns and bunch spacing should be more than 100 ns. Sensitivity of the monitor is close to 10 V per nanocoulomb. The equivalent scheme and the output signal shape are also presented. Such a monitor seems to be promising for the bunch charge measurements of beams like those in TESLA or ILC projects.

  1. Single photon detector with high polarization sensitivity.

    PubMed

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-01-01

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared. PMID:25875225

  2. Single photon detector with high polarization sensitivity

    PubMed Central

    Guo, Qi; Li, Hao; You, LiXing; Zhang, WeiJun; Zhang, Lu; Wang, Zhen; Xie, XiaoMing; Qi, Ming

    2015-01-01

    Polarization is one of the key parameters of light. Most optical detectors are intensity detectors that are insensitive to the polarization of light. A superconducting nanowire single photon detector (SNSPD) is naturally sensitive to polarization due to its nanowire structure. Previous studies focused on producing a polarization-insensitive SNSPD. In this study, by adjusting the width and pitch of the nanowire, we systematically investigate the preparation of an SNSPD with high polarization sensitivity. Subsequently, an SNSPD with a system detection efficiency of 12% and a polarization extinction ratio of 22 was successfully prepared. PMID:25875225

  3. High efficiency porphyrin sensitized mesoscopic solar cells

    NASA Astrophysics Data System (ADS)

    Giordano, Fabrizio; Yi, Chenyi; Teuscher, Joël.; Zakeeruddin, Shaik M.; Grätzel, Michael

    2014-10-01

    Dye-Sensitized Solar Cells (DSSC) represents a reliable technology, ready for the market and able to compete with silicon solar cells for specific fields of application. Porphyrin dyes allow reaching high power conversion efficiency in conjunction with cobalt redox electrolytes due to larger open circuit potentials. The bigger size of the cobalt complexes compared to standard iodide/triiodide redox couple hampers its percolation through the meso-porous TiO2 network, thus impairing the regeneration process. In case of porphyrin dyes mass transport problems in the electrolyte need to be carefully handled, due to the large size of the sensitizing molecule and the bulky cobalt complexes. Herein we report the study of structural variations on porphyrin sensitizers and their influence on the DSSC performance with cobalt based redox electrolyte.

  4. Rapid and sensitive hormonal profiling of complex plant samples by liquid chromatography coupled to electrospray ionization tandem mass spectrometry

    PubMed Central

    2011-01-01

    Background Plant hormones play a pivotal role in several physiological processes during a plant's life cycle, from germination to senescence, and the determination of endogenous concentrations of hormones is essential to elucidate the role of a particular hormone in any physiological process. Availability of a sensitive and rapid method to quantify multiple classes of hormones simultaneously will greatly facilitate the investigation of signaling networks in controlling specific developmental pathways and physiological responses. Due to the presence of hormones at very low concentrations in plant tissues (10-9 M to 10-6 M) and their different chemistries, the development of a high-throughput and comprehensive method for the determination of hormones is challenging. Results The present work reports a rapid, specific and sensitive method using ultrahigh-performance liquid chromatography coupled to electrospray ionization tandem spectrometry (UPLC/ESI-MS/MS) to analyze quantitatively the major hormones found in plant tissues within six minutes, including auxins, cytokinins, gibberellins, abscisic acid, 1-amino-cyclopropane-1-carboxyic acid (the ethylene precursor), jasmonic acid and salicylic acid. Sample preparation, extraction procedures and UPLC-MS/MS conditions were optimized for the determination of all plant hormones and are summarized in a schematic extraction diagram for the analysis of small amounts of plant material without time-consuming additional steps such as purification, sample drying or re-suspension. Conclusions This new method is applicable to the analysis of dynamic changes in endogenous concentrations of hormones to study plant developmental processes or plant responses to biotic and abiotic stresses in complex tissues. An example is shown in which a hormone profiling is obtained from leaves of plants exposed to salt stress in the aromatic plant, Rosmarinus officinalis. PMID:22098763

  5. High blood pressure and visual sensitivity

    NASA Astrophysics Data System (ADS)

    Eisner, Alvin; Samples, John R.

    2003-09-01

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

  6. A high sensitivity small animal SPECT system

    PubMed Central

    Mitchell, Gregory S; Cherry, Simon R

    2009-01-01

    Medical imaging using single gamma ray emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical SPECT (single photon emission computed tomography) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity—several tens of percent—with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo imaging of low-capacity receptor systems, aiding research into new tracer compounds, and reducing the cost and easing the regulatory burden of an experiment. Of course, a system with no collimator will not be able to approach the sub-millimeter spatial resolutions produced by the most advanced pinhole and collimated systems, but a high sensitivity system with resolution of order one centimeter could nonetheless find significant and new use in the many molecular imaging applications which do not require good spatial resolution—for example, screening applications for drug development or new imaging agents. Rather than as an alternative to high resolution SPECT systems, the high sensitivity system is proposed as a radiotracer alternative to optical imaging for small animals. We have developed a prototype system for mouse imaging applications. The scanner consists of two large, thin, closely spaced scintillation detectors. Simulation studies indicate that a FWHM spatial resolution of 7 mm is possible. In an in vivo mouse imaging study using the 99mTc labeled tracer MAG-3, the sensitivity of the system is measured to be 40%. Simple projection images created by analytically combining the two detectors' data show sufficient resolution to observe the dynamic distribution of the radiotracer in the mouse. PMID:19190360

  7. High sensitive materials in medical holographic microscopy

    NASA Astrophysics Data System (ADS)

    Osanlou, A.; Snashall, E.; Osanlou, O.; Osanlou, R.; Mirlis, E.; Shi, Lishen; Bjelkhagen, H.

    2015-02-01

    High sensitivity is defined in relation to the energy required to perform holographic recording. High sensitivity in silver halide materials is their main advantage over other similarly high resolving power holographic recording materials. This work reports progress on the development of silver halide based 'true colour holographic imaging', under a microscope. A thin layer of ultrafine grains of silver halide crystals of around 10 nm average diameter, dispersed in a colloid and coated on a substrate is used as the recording media. The significance of this method so far, is in its ability to produce 'true colour' three-dimensional images of specimen. The recordings have an appreciable depth, permitting the observer to scan through the image under a microscope, as one might with a real specimen sample. Current methods could perform ' True colour holographic imaging' directly under a microscope. The recording methodology has the potential for deeper complex and scattering media imaging, using very small pulses of appropriate laser wavelengths. The methodology, using novel nanosize panchromatic recording media consisting of dispersed fine nano grain crystals, could potentially revolutionise related medical imaging techniques. Future development of digital media will allow it to be utilized in this manner.

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

    PubMed

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

    2014-11-01

    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 (2.1×50 mm, 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 0.5-500 ng/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 24 h, 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

  9. Photodetector having high speed and sensitivity

    DOEpatents

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

    1991-01-01

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

  10. High speed curved position sensitive detector

    DOEpatents

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

    1989-01-01

    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.

  11. Highly sensitive silicon microreactor for catalyst testing

    NASA Astrophysics Data System (ADS)

    Henriksen, Toke R.; Olsen, Jakob L.; Vesborg, Peter; Chorkendorff, Ib; Hansen, Ole

    2009-12-01

    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 3×1014 molecules s-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 ?m2 are conveniently characterized with the device.

  12. Transportable high sensitivity small sample radiometric calorimeter

    SciTech Connect

    Wetzel, J.R.; Biddle, R.S.; Cordova, B.S.; Sampson, T.E.; Dye, H.R.; McDow, J.G.

    1998-12-31

    A new small-sample, high-sensitivity transportable radiometric calorimeter, which can be operated in different modes, contains an electrical calibration method, and can be used to develop secondary standards, will be described in this presentation. The data taken from preliminary tests will be presented to indicate the precision and accuracy of the instrument. The calorimeter and temperature-controlled bath, at present, require only a 30-in. by 20-in. tabletop area. The calorimeter is operated from a laptop computer system using unique measurement module capable of monitoring all necessary calorimeter signals. The calorimeter can be operated in the normal calorimeter equilibration mode, as a comparison instrument, using twin chambers and an external electrical calibration method. The sample chamber is 0.75 in (1.9 cm) in diameter by 2.5 in. (6.35 cm) long. This size will accommodate most {sup 238}Pu heat standards manufactured in the past. The power range runs from 0.001 W to <20 W. The high end is only limited by sample size.

  13. A case of high noise sensitivity

    NASA Astrophysics Data System (ADS)

    Murata, M.; Sakamoto, H.

    1995-10-01

    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.

  14. Transplantation in the highly sensitized pediatric patient.

    PubMed

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

    2014-06-01

    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

  15. High-Sensitivity GaN Microchemical Sensors

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

  16. High sensitivity leak detection method and apparatus

    DOEpatents

    Myneni, G.R.

    1994-09-06

    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.

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

    PubMed

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

    2013-02-15

    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

  18. ORIGINAL PAPER Allergen microarrays on high-sensitivity silicon slides

    E-print Network

    ORIGINAL PAPER Allergen microarrays on high-sensitivity silicon slides Marina Cretich & Daniela with sensitizations to inhalant allergens. We compared the performance of silicon versus glass substrates that reproducibility of the microarray on glass supports was not different from available data on allergen arrays

  19. High surface plasmon resonance sensitivity enabled by optical disks.

    PubMed

    Dou, Xuan; Phillips, Blayne M; Chung, Pei-Yu; Jiang, Peng

    2012-09-01

    We report a systematic, experimental, and theoretical investigation on the surface plasmon resonance (SPR) sensing using optical disks with different track pitches, including Blu-ray disk (BD), digital versatile disk (DVD), and compact disk (CD). Optical reflection measurements indicate that CD and DVD exhibit much higher SPR sensitivity than BD. Both experiments and finite-difference time-domain simulations reveal that the SPR sensitivity is significantly affected by the diffraction order of the SPR peaks and higher diffraction order results in lower sensitivity. Numerical simulations also show that very high sensitivity (?1600??nm per refractive index unit) is achievable by CDs. PMID:22940989

  20. Frequency Selective Surfaces for High-Sensitivity Terahertz Sensors

    Microsoft Academic Search

    Christian Debus; Peter Haring Bolivar

    2007-01-01

    We present a frequency selective surface (FSS) of asymmetric split-ring resonators for terahertz (THz) sensor applications. Multiple resonances of the rings combine to sharp edges in the FSS's frequency response to achieve high sensitivity.

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

    NASA Astrophysics Data System (ADS)

    Niu, Zhe; Zhao, Yulong; Tian, Bian

    2014-01-01

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

  2. A high sensitivity position-sensitive detector based on AuSiO2Si structure

    Microsoft Academic Search

    Liming Chi; Pengfei Zhu; Hui Wang; Xiaoan Huang; Xiangting Li

    2011-01-01

    A novel position-sensitive detector (PSD) based on the metal-oxide-semiconductor (MOS) structure, which is simply fabricated by an n-type Si substrate, a thin native SiO2 layer and an Au film, is reported in this work. This detector shows a large lateral photovoltage (LPV) with high sensitivity and good linearity. Furthermore, the LPV of this structure greatly depends on the incident angle

  3. High sensitivity optomechanical reference accelerometer over 10 kHz

    E-print Network

    Felipe Guzman Cervantes; Lee Kumanchik; Jon Pratt; Jacob Taylor

    2014-08-28

    We present an optically-detected mechanical accelerometer that achieves a sensitivity of 100 ng/rtHz over a bandwidth of 10kHz and is traceable. We have incorporated a Fabry-Perot fiber-optic micro-cavity that is currently capable of measuring the test-mass displacement with sensitivities of 200 am/rtHz, and whose length determination enables traceability to the International System of Units (SI). The compact size and high mQ-product achieved combined with the high sensitivity and simplicity of the implemented optical detection scheme highlight our device and this category of accelerometers, outlining a path for high sensitivity reference acceleration measurements and observations in seismology and gravimetry.

  4. Determination of a highly selective mixed-affinity sigma receptor ligand, in rat plasma by ultra performance liquid chromatography mass spectrometry and its application to a pharmacokinetic study.

    PubMed

    Jamalapuram, Seshulatha; Vuppala, Pradeep K; Mesangeau, Christophe; McCurdy, Christopher R; Avery, Bonnie A

    2012-04-01

    A selective, rapid and sensitive ultra performance liquid chromatography mass spectrometry (UPLC/MS) method was developed and validated to quantitate a highly selective mixed-affinity sigma receptor ligand, CM156 (3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d] thiazole-2(3H)-thione), in rat plasma. CM156 and the internal standard (aripiprazole) were extracted from plasma samples by a single step liquid-liquid extraction using chloroform. The analysis was carried out on an ACQUITY UPLC™ BEH HILIC column (1.7 ?m, 2.1 mm×50 mm) with isocratic elution at flow rate of 0.2 mL/min using 10mM ammonium formate in 0.1% formic acid and acetonitrile (10:90) as the mobile phase. The detection of the analyte was performed on a mass spectrometer operated in selected ion recording (SIR) mode with positive electrospray ionization (ESI). The validated analytical method resulted in a run time of 4 min and the retention times observed were 2.6±0.1 and 2.1±0.1 min for CM156 and the IS, respectively. The calibration curve exhibited excellent linearity over a concentration range of 5-4000 ng/mL with the lower limit of quantification of 5 ng/mL. The intra- and inter-day precision values were below 15% and accuracy ranged from -6.5% to 5.0%. The mean recovery of CM156 from plasma was 96.8%. The validated method was applied to a pilot intravenous pharmacokinetic study in rats. PMID:22406103

  5. Determination of a highly selective mixed-affinity sigma receptor ligand, in rat plasma by ultra performance liquid chromatography mass spectrometry and its application to a pharmacokinetic study

    PubMed Central

    Jamalapuram, Seshulatha; Vuppala, Pradeep K.; Mesangeau, Christophe; McCurdy, Christopher R.; Avery, Bonnie A.

    2014-01-01

    A selective, rapid and sensitive ultra performance liquid chromatography mass spectrometry (UPLC/MS) method was developed and validated to quantitate a highly selective mixed-affinity sigma receptor ligand, CM156 (3-(4-(4-cyclohexylpiperazin-1-yl)butyl)benzo[d] thiazole-2(3H)-thione), in rat plasma. CM156 and the internal standard (aripiprazole) were extracted from plasma samples by a single step liquid–liquid extraction using chloroform. The analysis was carried out on an ACQUITY UPLCTM BEH HILIC column (1.7 µm, 2.1 mm × 50 mm) with isocratic elution at flow rate of 0.2 mL/min using 10 mM ammonium formate in 0.1% formic acid and acetonitrile (10:90) as the mobile phase. The detection of the analyte was performed on a mass spectrometer operated in selected ion recording (SIR) mode with positive electrospray ionization (ESI). The validated analytical method resulted in a run time of 4 min and the retention times observed were 2.6 ± 0.1 and 2.1 ± 0.1 min for CM156 and the IS, respectively. The calibration curve exhibited excellent linearity over a concentration range of 5–4000 ng/mL with the lower limit of quantification of 5 ng/mL. The intra- and inter-day precision values were below 15% and accuracy ranged from ?6.5% to 5.0%. The mean recovery of CM156 from plasma was 96.8%. The validated method was applied to a pilot intravenous pharmacokinetic study in rats. PMID:22406103

  6. Highly sensitive wide bandwidth photodetectors using chemical vapor deposited graphene

    NASA Astrophysics Data System (ADS)

    Goo Kang, Chang; Kyung Lee, Sang; Jin Yoo, Tae; Park, Woojin; Jung, Ukjin; Ahn, Jinho; Hun Lee, Byoung

    2014-04-01

    A photodetector generating a nearly constant photocurrent in a very wide spectral range from ultraviolet (UV) to infrared has been demonstrated using chemical vapor deposited (CVD) graphene. Instability due to a photochemical reaction in the UV region has been minimized using an Al2O3 passivation layer, and a responsivity comparable to that of Highly Ordered Pyrolytic Graphite graphene photodetectors of ˜8 mA/W has been achieved at a 0.1 V bias, despite high defect density in the CVD graphene. A highly sensitive multi-band photodetector using graphene has many potential applications including optical interconnects, multi-band imaging sensors, highly sensitive motion detectors, etc.

  7. High-sensitivity three-mode optomechanical transducer

    NASA Astrophysics Data System (ADS)

    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.

    2011-12-01

    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 CO2 laser thermal tuning. We demonstrate a displacement sensitivity of ˜1×10-17m/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 ˜2×10-20m/Hz limited by the quantum shot noise is achievable with optimization of the cavity parameters.

  8. Pressure sensitive paint suitable to high Knudsen number regime

    Microsoft Academic Search

    Hideo Mori; Tomohide Niimi; Madoka Hirako; Hiroyuki Uenishi

    2006-01-01

    Pressure sensitive paint (PSP) techniques have the capability to be applied to high Knudsen number flows, such as low density gas flows, micro-flows, and so on. In this study, to inspect the feasibility of PSP for measurement of pressure on a solid surface in high Knudsen number flows, the fundamental properties of PSPs are examined, especially in the range of

  9. Pressure sensitive paint suitable to high Knudsen number regime

    NASA Astrophysics Data System (ADS)

    Mori, Hideo; Niimi, Tomohide; Hirako, Madoka; Uenishi, Hiroyuki

    2006-06-01

    Pressure sensitive paint (PSP) techniques have the capability to be applied to high Knudsen number flows, such as low density gas flows, micro-flows, and so on. In this study, to inspect the feasibility of PSP for measurement of pressure on a solid surface in high Knudsen number flows, the fundamental properties of PSPs are examined, especially in the range of pressure below 130 Pa (about 1 Torr). As a result, it is clarified that the PSP using poly(TMSP) as a binder and using PdOEP or PdTFPP as a luminophore has very high sensitivity to oxygen pressure under low pressure conditions below 130 Pa. Pressure sensitivity to nitrogen monoxide is also examined for the above PSPs, and it is clarified that PdTFPP bound by poly(TMSP) has very high sensitivity while PdOEP has very low sensitivity to nitrogen monoxide. The combination of the PdTFPP-based PSP and NO-LIF technique enables composite measurement of flow field structures and surface pressure in the high-Kn regime.

  10. Analytical Glycobiology at High Sensitivity: Current Approaches and Directions

    PubMed Central

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

    2013-01-01

    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

  11. High-sensitivity cardiac troponins in everyday clinical practice

    PubMed Central

    Mair, Johannes

    2014-01-01

    High-sensitivity cardiac troponin (hs-cTn) assays are increasingly being used in many countries worldwide, however, a generally accepted definition of high-sensitivity is still pending. These assays enable cTn measurement with a high degree of analytical sensitivity with a low analytical imprecision at the low measuring range of cTn assays (coefficient of variation of < 10% at the 99th percentile upper reference limit). One of the most important advantages of these new assays is that they allow novel, more rapid approaches to rule in or rule out acute coronary syndromes (ACSs) than with previous cTn assay generations which are still more commonly used in practice worldwide. hs-cTn is also more sensitive for the detection of myocardial damage unrelated to acute myocardial ischemia. Therefore, the increase in early diagnostic sensitivity of hs-cTn assays for ACS comes at the cost of a reduced ACS specificity, because more patients with other causes of acute or chronic myocardial injury without overt myocardial ischemia are detected than with previous cTn assays. As hs-cTn assays are increasingly being adopted in clinical practice and more hs-cTn assays are being developed, this review attempts to synthesize the available clinical data to make recommendations for their everyday clinical routine use. PMID:24772257

  12. Determination of impact sensitivity of materials at high pressures

    NASA Technical Reports Server (NTRS)

    Davis, L.; Pippen, D.; Stradling, J.; Whitaker, D.

    1972-01-01

    Compact device is used to determine impact sensitivity of material in static, high pressure, gaseous environment. It can also be instrumented to monitor and record pressure, temperature, and striker impact force. Device is used in conjunction with commercially available liquid oxygen impact tester which provides impact energy.

  13. 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...

  14. A high sensitivity inductive sensor for blade tip clearance measurement

    NASA Astrophysics Data System (ADS)

    Du, Li; Zhu, Xiaoliang; Zhe, Jiang

    2014-06-01

    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.

  15. High-sensitivity CCD-based x-ray detector

    Microsoft Academic Search

    Walter C. Phillips; Alexander Stewart; M. Stanton; I. Naday; C. Ingersoll

    2002-01-01

    The detector is designed for imaging measurements requiring relatively high sensitivity and high spatial resolution. The detector can discriminate single X-ray photons, yet has the wide dynamic range (10000:1) associated with integrating detectors. A GdOS phosphor screen converts the incoming X-ray image into an optical image. The optical image is coupled (without demagnification) to the CCD image sensor using a

  16. Highly sensitive detection of Shigella flexneri using fluorescent silica nanoparticles.

    PubMed

    Li, Yan; Xu, Weijia

    2009-10-01

    Robust signal amplification tactic is a good solution for improving detection sensitivity. Unprocessed fluorophores have many limitations. Here we describe an effective strategy for highly sensitive detection of bacteria by using fluorescent conjugated nanoparticles. The nanoparticles were synthesized using silica as matrix. Fluorescein isothiocyanate distributed in the matrix. S. flexneri specific antibody was coated on the surface of the nanoparticles. Compared to the traditional fluorescent antibody, these antibody-coated fluorescent conjugated nanoparticles were resistant to photobleaching and could ensure prolonged microscope checking for a small number of target bacteria. These nanoparticles could be used in routine bacterial detection for different species. PMID:20128444

  17. Electrooptic modulation methods for high sensitivity tunable diode laser spectroscopy

    NASA Technical Reports Server (NTRS)

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

    1990-01-01

    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.

  18. Electrooptic modulation methods for high sensitivity tunable diode laser spectroscopy.

    PubMed

    Glenar, D A; Jennings, D E; Nadler, S

    1990-05-20

    A CdTe phase modulator and low power rf source have been used with Pb-salt tunable diode lasers operating near 8 microm to generate optical sidebands for high sensitivity absorption spectroscopy. Sweep averaged, first-derivative sample spectra of CH(4) 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. PMID:20563162

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

    DOEpatents

    Watson, Scott A; Bender, III, Howard A

    2014-11-18

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

  20. High sensitivity of positron annihilation to thermal oxidation of polyethylene

    NASA Astrophysics Data System (ADS)

    Ito, Kenji; Kobayashi, Yoshinori; Nanasawa, Atsushi

    2003-01-01

    We demonstrate the high sensitivity of positron annihilation to compositional changes related to the thermal degradation of polyethylene (PE). Positron annihilation ?-ray and lifetime measurements were conducted for PE films with and without antioxidant (1000-ppm Ciba® IRGANOX® 1076), subjected to heat treatment at 100 °C for different periods, to a maximum of 30 days. For the film without antioxidant, the positron Doppler parameter (S) and ortho-positronium formation probability (Io-Ps) appreciably decreased with increased heat treatment times, whereas they barely changed for the film with antioxidant. This, together with the Fourier transform infrared measurements, demonstrated that the variations of S and Io-Ps are caused by the thermal oxidation of PE. The S parameter was found to be sensitive to the early stage of degradation, where the carbonyl concentration is inferred to be lower than 100 ppm. The high sensitivity results from the large positron mobility in PE and from the high positron affinity of oxygen-containing polar groups. This work provides the basis for an application of positron annihilation to sensitive detection of the initial degradation of PE and other nonpolar polymers.

  1. A High Sensitivity Ultraviolet Spectrograph for the THEIA Mission

    NASA Astrophysics Data System (ADS)

    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

    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.

  2. High-sensitivity linear piezoresistive transduction for nanomechanical beam resonators

    NASA Astrophysics Data System (ADS)

    Sansa, Marc; Fernández-Regúlez, Marta; Llobet, Jordi; San Paulo, Álvaro; Pérez-Murano, Francesc

    2014-07-01

    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.

  3. High-sensitivity linear piezoresistive transduction for nanomechanical beam resonators.

    PubMed

    Sansa, Marc; Fernández-Regúlez, Marta; Llobet, Jordi; San Paulo, Álvaro; Pérez-Murano, Francesc

    2014-01-01

    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

  4. High sensitivity glucose sensor based on optical heterodyne phase detection

    NASA Astrophysics Data System (ADS)

    Lin, Jiun-You; Chen, Kun-Huang; Chen, Jing-Heng; Liao, Yu-Cheng; Lin, Yu-Hsien

    2009-07-01

    Measurements of glucose concentration are important parts of biochemical analyses. Based on the principles of the common-path heterodyne interferometry, we develop a high sensitivity optical sensor for measuring glucose concentration. A heterodyne light beam after transmitted through a glucose solution passes through some polarization components for interference. The phase difference determined with heterodyne interferometric technique of the interference signal is greatly enhanced as a result of proper azimuth angles of some polarization components, and a high sensitivity measurement of glucose concentration can be achieved. The feasibility of the measuring method was demonstrated by our experimental results. This optical sensor should bear the merits of high accuracy, short sample medium length, and simpler operational endeavor.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

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

  6. High-sensitivity diamond magnetometer with nanoscale resolution

    NASA Astrophysics Data System (ADS)

    Cappellaro, Paola

    2009-03-01

    We will discuss our recent work on using isolated electronic spins in the solid-state as sensitive magnetic sensors [1,2]. This novel approach to magnetometry is enabled by the good coherence properties of electronic qubits, such as the spins associated with Nitrogen-Vacancy (NV) centers in diamond, as well as by advanced techniques for their coherent control. The key feature of this solid-state magnetometer is the possibility to confine the sensing spins into a crystal of nanometer size that can be brought extremely close to the magnetic field source, thus achieving high spatial resolution. Our first experiments demonstrate that the resulting magnetic sensor provides an unprecedented combination of ultra-high sensitivity and spatial resolution. The ultimate sensitivity limit is set by the interaction of the spin sensor with its environment and in particular the nuclear and electronic spin bath. As an outlook, we will discuss how engineering, controlling or harnessing the environment can lead to better sensitivity, even beyond the standard quantum limit. Finally, we will outline several exciting applications of the novel magnetic sensors in areas ranging from bio- and materials science to fundamental physics and single electronic and nuclear spin detection. [4pt] [1] J. M. Taylor, et al. Nature Phys. 4, 810-816 (2008). [0pt] [2] J. R. Maze, et al. Nature 455, 644 - 647 (2008)

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

    NASA Astrophysics Data System (ADS)

    Kawahara, H.; Asada, T.; Naka, T.; Naganawa, N.; Kuwabara, K.; Nakamura, M.

    2014-08-01

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

  8. Quantum-Dot-Sensitized Solar Cell with Unprecedentedly High Photocurrent

    PubMed Central

    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

    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

  9. Structural glycomic analyses at high sensitivity: a decade of progress.

    PubMed

    Alley, William R; Novotny, Milos V

    2013-01-01

    The field of glycomics has recently advanced in response to the urgent need for structural characterization and quantification of complex carbohydrates in biologically and medically important applications. The recent success of analytical glycobiology at high sensitivity reflects numerous advances in biomolecular mass spectrometry and its instrumentation, capillary and microchip separation techniques, and microchemical manipulations of carbohydrate reactivity. The multimethodological approach appears to be necessary to gain an in-depth understanding of very complex glycomes in different biological systems. PMID:23560930

  10. Horizontal film balance having wide range and high sensitivity

    DOEpatents

    Abraham, B.M.; Miyano, K.; Ketterson, J.B.

    1983-11-08

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed. 5 figs.

  11. Horizontal film balance having wide range and high sensitivity

    DOEpatents

    Abraham, B.M.; Miyano, K.; Ketterson, J.B.

    1981-03-05

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed.

  12. Horizontal film balance having wide range and high sensitivity

    DOEpatents

    Abraham, Bernard M. (Oak Park, IL); Miyano, Kenjiro (Downers Grove, IL); Ketterson, John B. (Evanston, IL)

    1983-01-01

    A thin-film, horizontal balance instrument is provided for measuring surface tension (surface energy) of thin films suspended on a liquid substrate. The balance includes a support bearing and an optical feedback arrangement for wide-range, high sensitivity measurements. The force on the instrument is balanced by an electromagnet, the current through the magnet providing a measure of the force applied to the instrument. A novel float construction is also disclosed.

  13. High-sensitivity, single-beam n2 measurements

    Microsoft Academic Search

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

    1989-01-01

    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

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

    PubMed Central

    Alley, William R.; Novotny, Milos V.

    2014-01-01

    The field of glycomics has recently advanced in response to the urgent need for structural characterization and quantification of complex carbohydrates in biologically and medically important applications. The recent success of analytical glycobiology at high sensitivity reflects numerous advances in biomolecular mass spectrometry and its instrumentation, capillary and microchip separation techniques, and microchemical manipulations of carbohydrate reactivity. The multimethodological approach appears to be necessary to gain an in-depth understanding of very complex glycomes in different biological systems. PMID:23560930

  15. High sensitive FBG pressure sensor using metal bellows

    NASA Astrophysics Data System (ADS)

    Vengal Rao, P.; Srimannarayana, K.; Sai Shankar, M.; Kishore, P.

    2013-09-01

    A fiber-optic sensor scheme, capable of the simultaneous measurement of pressure and temperature using two in-line Fiber Bragg Gratings (FBGs) is reported. Sensor head is configured by embedding the two FBGs with metal bellows, such that FBG1 is sensitive to both pressure and temperature, whereas FBG2 is only sensitive to temperature. High pressure sensitivity is achieved because of the lower spring rate in longitudinal direction to that of the large elastic modulus in transverse direction of the metal bellows. Pressure and temperature measurement is made by monitoring the shift of Bragg wavelengths of the FBGs corresponds to variation in pressure and temperature. From the test results, the obtained pressure and temperature sensitivities are 86 pm/psi and 9.17 pm/°C, over a dynamic range of 0-40 psi pressure, and 25-110°C temperature measurements respectively. The experimental results well agreed with the theoretical results and show good linearity. This simple design, economical and all fiber optic sensors can be used for liquid and gas pressure measurements, and under-water applications.

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

    PubMed Central

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

    2013-01-01

    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

  17. High-speed high-sensitivity low-noise scientific CMOS image sensors

    Microsoft Academic Search

    Stuart Kleinfelder

    2004-01-01

    Image sensors for scientific applications face unusually demanding performance requirements for speed, sensitivity, noise, dynamic range and data throughput. Dynamic proton radiography, for example, requires both extremely high frame rates (multi-MHz) and high dynamic range (~80 dB). Electron microscopy, particle physics, nuclear science and astrophysics applications requires high sensitivity and low noise for single-photon\\/single charged particle efficiency, often in extremely

  18. High-sensitivity photoacoustic absorption spectroscopy of nonlinear optical materials

    NASA Astrophysics Data System (ADS)

    Waasem, Niklas; Buse, Karsten; Kühnemann, Frank

    2013-03-01

    Nonlinear optical materials are important to extend the spectral coverage of existing lasers, mainly via frequency doubling and with optical parametric oscillators. The quality of the materials and components, e.g. in terms of residual absorption, is pivotal for the performance of the devices. The paper presents high-sensitivity absorption measurements of nonlinear optical materials. They were performed using a photoacoustic spectrometer which combines high sensitivity with broad spectral coverage. This allows one not only to quantify the level of residual absorption but also to assist in the characterization of the materials in terms of optically relevant impurities and imperfections. The spectrometer covers the wavelength range between 407 and 2600 nm using a pulsed optical parametric oscillator as excitation source. Pulse energies up to 100 mJ allow one to record absorption spectra with a sensitivity down to 10 ppm/cm. The paper presents spectra of lithium niobate and lithium triborate crystals which are important for highpower nonlinear optical applications. The results are discussed with respect to material impurities and the suitability of individual samples for frequency conversion.

  19. A high-sensitivity small animal SPECT system.

    PubMed

    Mitchell, Gregory S; Cherry, Simon R

    2009-03-01

    Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity-several tens of percent-with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo imaging of low-capacity receptor systems, aiding research into new tracer compounds, and reducing the cost and easing the regulatory burden of an experiment. Of course, a system with no collimator will not be able to approach the submillimeter spatial resolutions produced by the most advanced pinhole and collimated systems, but a high-sensitivity system with resolution of order 1 cm could nonetheless find significant and new use in the many molecular imaging applications which do not require good spatial resolution-for example, screening applications for drug development or new imaging agents. Rather than as an alternative to high-resolution SPECT systems, the high-sensitivity system is proposed as a radiotracer alternative to optical imaging for small animals. We have developed a prototype system for mouse imaging applications. The scanner consists of two large, thin, closely spaced scintillation detectors. Simulation studies indicate that a FWHM spatial resolution of 7 mm is possible. In an in vivo mouse imaging study using the (99m)Tc labeled tracer MAG-3, the sensitivity of the system is measured to be 40%. Simple projection images created by analytically combining the two detectors' data show sufficient resolution to observe the dynamic distribution of the radiotracer in the mouse. PMID:19190360

  20. A high-sensitivity small animal SPECT system

    NASA Astrophysics Data System (ADS)

    Mitchell, Gregory S.; Cherry, Simon R.

    2009-03-01

    Medical imaging using single gamma-ray-emitting radionuclides typically makes use of parallel hole collimators or pinholes in order to achieve good spatial resolution. However, a tradeoff in sensitivity is inherent in the use of a collimator, and modern preclinical single photon emission computed tomography (SPECT) systems detect a very small fraction of emitted gamma rays, often less than 0.1%. A system for small animal SPECT imaging which uses no collimators could potentially achieve very high sensitivity—several tens of percent—with reasonably sized detectors. This would allow two significant improvements in preclinical studies: images could be obtained more rapidly, allowing higher throughput for screening applications, or for dynamic processes to be observed with very good time resolution; and images could be obtained with less radioactive tracer, making possible the in vivo imaging of low-capacity receptor systems, aiding research into new tracer compounds, and reducing the cost and easing the regulatory burden of an experiment. Of course, a system with no collimator will not be able to approach the submillimeter spatial resolutions produced by the most advanced pinhole and collimated systems, but a high-sensitivity system with resolution of order 1 cm could nonetheless find significant and new use in the many molecular imaging applications which do not require good spatial resolution—for example, screening applications for drug development or new imaging agents. Rather than as an alternative to high-resolution SPECT systems, the high-sensitivity system is proposed as a radiotracer alternative to optical imaging for small animals. We have developed a prototype system for mouse imaging applications. The scanner consists of two large, thin, closely spaced scintillation detectors. Simulation studies indicate that a FWHM spatial resolution of 7 mm is possible. In an in vivo mouse imaging study using the 99mTc labeled tracer MAG-3, the sensitivity of the system is measured to be 40%. Simple projection images created by analytically combining the two detectors' data show sufficient resolution to observe the dynamic distribution of the radiotracer in the mouse.

  1. Highly Sensitive Measurements of 222Rn Diffusion and Emanation

    NASA Astrophysics Data System (ADS)

    Zuzel, Grzegorz

    2005-09-01

    Highly sensitive techniques for determination of the 222Rn emanation from solids and diffusion through different membranes are presented. 222Rn and its daughters are measured via the alpha decays in special proportional counters at the absolute sensitivity of ˜30 ?Bq. Radon diffusion can be measured at the level of ˜10-13 cm2/s. Several samples were examined, e.g. stainless steel, teflon, various gaskets (emanation and diffusion measurements) and tanks. A combination of measurements of the 222Rn diffusion and emanation of thin nylon foils (used in the Borexino experiment) allowed the determination of 226Ra in the materials of interest at the level of ˜10-12 g/g 238U-equivalent.

  2. High-sensitivity uncooled microcantilever infrared imaging arrays

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Maurer, Gregory; Jiang, Lijun; Simelgor, Gregory

    2006-05-01

    The design and operation of an advanced bimorph microcantilever based infrared imaging detector are presented. This technology has the potential to achieve very high sensitivities due to its inherent high responsivity and low noise sensor and detection electronics. The sensor array is composed of bimaterial, thermally sensitive microcantilever structures that are the moving elements of variable plate capacitors. The heat sensing microcantilever structures are integrated with CMOS control and amplification electronics to produce a low cost imager that is compatible with standard silicon IC foundry processing and materials. The bimorph sensor structure is fabricated using low thermal expansion, high thermal isolation silicon oxide and oxynitride materials, and a high thermal expansion aluminum alloy bimetal. The microcantilever paddle is designed to move away from the substrate at elevated imaging temperatures, leading to large modeled sensor dynamic ranges (~16 bits). A temperature coefficient of capacitance, ?C/C, (equivalent to TCR for microbolometers) above 30% has been modeled and measured for these structures, leading to modeled NEDT < 20 mK and thermal time constants in the 5-10 msec range giving a figure-of-merit [1] NEDT.Tau = 100-200 mK.msec. The development efforts to date have focused on the fabrication of 160x120 pixel arrays with 50 micron pitch pixels. Results from detailed thermo-electro-opto-mechanical modeling of the operation of these sensors are compared with experimental measurements from various test and integrated sensor structures and arrays.

  3. Highly Stretchable and Sensitive Unidirectional Strain Sensor via Laser Carbonization.

    PubMed

    Rahimi, Rahim; Ochoa, Manuel; Yu, Wuyang; Ziaie, Babak

    2015-03-01

    In this paper, we present a simple and low-cost technique for fabricating highly stretchable (up to 100% strain) and sensitive (gauge factor of up to 20?000) strain sensors. Our technique is based on transfer and embedment of carbonized patterns created through selective laser pyrolization of thermoset polymers, such as polyimide, into elastomeric substrates (e.g., PDMS or Ecoflex). Embedded carbonized materials are composed of partially aligned graphene and carbon nanotube (CNT) particles and show a sharp directional anisotropy, which enables the fabrication of extremely robust, highly stretchable, and unidirectional strain sensors. Raman spectrum of pyrolized carbon regions reveal that under optimal laser settings, one can obtain highly porous carbon nano/microparticles with sheet resistances as low as 60 ?/?. Using this technique, we fabricate an instrumented latex glove capable of measuring finger motion in real-time. PMID:25686021

  4. Position sensitive detection of neutrons in high radiation background field.

    PubMed

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

    2014-01-01

    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 ?m(2)) spectroscopic Timepix detector adapted for neutron detection utilizing very thin (10)B 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). PMID:24517756

  5. Position sensitive detection of neutrons in high radiation background field

    SciTech Connect

    Vavrik, D., E-mail: vavrik@itam.cas.cz [Institute of Experimental and Applied Physics, Czech Technical University in Prague, Horska 3a/22, Prague (Czech Republic); Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic); Jakubek, J.; Pospisil, S. [Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic)] [Institute of Theoretical and Applied Mechanics, Academy of Sciences of the Czech Republic, Prosecka 76, 190 00 Prague 9 (Czech Republic); Vacik, J. [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez, 250 68 Prague, Czech Republic (Czech Republic)] [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Rez, 250 68 Prague, Czech Republic (Czech Republic)

    2014-01-15

    We present the development of a high-resolution position sensitive device for detection of slow neutrons in the environment of extremely high ? and e{sup ?} radiation background. We make use of a planar silicon pixelated (pixel size: 55 × 55 ?m{sup 2}) spectroscopic Timepix detector adapted for neutron detection utilizing very thin {sup 10}B 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{sup ?4}.

  6. High-sensitivity piezoelectric perovskites for magnetoelectric composites

    NASA Astrophysics Data System (ADS)

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

    2015-02-01

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

  7. The Georgia Tech High Sensitivity Microwave Measurement System

    NASA Technical Reports Server (NTRS)

    Deboer, David R.; Steffes, Paul G.

    1996-01-01

    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.

  8. High Sensitivity Torsion Balance Tests for LISA Proof Mass Modeling

    E-print Network

    S. Schlamminger; C. A. Hagedorn; M. G. Famulare; S. E. Pollack; J. H. Gundlach

    2007-02-08

    We have built a highly sensitive torsion balance to investigate small forces between closely spaced gold coated surfaces. Such forces will occur between the LISA proof mass and its housing. These forces are not well understood and experimental investigations are imperative. We describe our torsion balance and present the noise of the system. A significant contribution to the LISA noise budget at low frequencies is the fluctuation in the surface potential difference between the proof mass and its housing. We present first results of these measurements with our apparatus.

  9. High sensitivity charge amplifier for ion beam uniformity monitor

    DOEpatents

    Johnson, Gary W. (Livermore, CA)

    2001-01-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-12-01

    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.

  11. High refractive index and temperature sensitivity LPGs for high temperature operation

    NASA Astrophysics Data System (ADS)

    Nascimento, I. M.; Gouveia, C.; Jana, Surnimal; Bera, Susanta; Baptista, J. M.; Moreira, Paulo; Biwas, Palas; Bandyopadhyay, Somnath; Jorge, Pedro A. S.

    2013-11-01

    A fiber optic sensor for high sensitivity refractive index and temperature measurement able to withstand temperature up to 450 °C is reported. Two identical LPG gratings were fabricated, whereas one was coated with a high refractive index (~1.78) sol-gel thin film in order to increase its sensitivity to the external refractive index. The two sensors were characterized and compared in refractive index and temperature. Sensitivities of 1063 nm/RIU (1.338 - 1.348) and 260 pm/°C were achieved for refractive index and temperature, respectively.

  12. High Sensitivity Surface Enhanced Raman Scattering Detection of Tryptophan

    NASA Astrophysics Data System (ADS)

    Kandakkathara, Archana

    Raman spectroscopy has the capability of providing detailed information about molecular structure, but the extremely small cross section of Raman scattering prevents this technique from applications requiring high sensitivity. Surface enhanced Raman scattering (SERS) on the other hand provides strongly increased Raman signal from molecules attached to metallic nanostructures. SERS is thus a promising technique for high sensitivity analytical applications. One particular area of interest is the application of such techniques for the analysis of the composition of biological cells. However, there are issues which have to be addressed in order to make SERS a reliable technique such as the optimization of conditions for any given analyte, understanding the kinetic processes of binding of the target molecules to the nanostructures and understanding the evolution and coagulation of the nanostructures, in the case of colloidal solutions. The latter processes introduce a delay time for the observation of maximum enhancement factors which must be taken into account for any given implementation of SERS. In the present thesis the goal was to develop very sensitive SERS techniques for the measurement of biomolecules of interest for analysis of the contents of cells. The techniques explored could be eventually be applicable to microfluidic systems with the ultimate goal of analyzing the molecular constituents of single cells. SERS study of different amino acids and organic dyes were performed during the course of this thesis. A high sensitivity detection system based on SERS has been developed and spectrum from tryptophan (Trp) amino acid at very low concentration (10-8 M) has been detected. The concentration at which good quality SERS spectra could be detected from Trp is 4 orders of magnitude smaller than that previously reported in literature. It has shown that at such low concentrations the SERS spectra of Trp are qualitatively distinct from the spectra commonly reported in literature. These distinctions are attributed to the unique binding geometry of Trp molecules to the small silver nanoclusters at these low concentrations. Background electrolytes in the solution can have a significant role in SERS experiment as it helps in the binding of molecules to the metallic structures and stabilizes the colloid in some cases We performed a study of effects of different electrolytes and an optimization of electrolytes has been carried out, which leads to the high enhancement reported in this thesis. The SERS detection has also been performed in microfluidic and flow cell geometries which enable a combination of high sensitivity of the SERS with the low volume requirements of microfluidic devices. A Teflon AF capillary was used for performing liquid core waveguide (LCW) SERS measurements. With this geometry the enhancement obtained was about a factor of 10 compared to that from cuvette so the detection limit could be further decreased by a factor of 10 in LCW reaching 10 -9 - 10-10M for Trp amino acid. The enhanced sensitivity and better understanding of the optimum conditions for SERS developed in the thesis are important since they now could allow the possibility of assays of the chemical constituents of single cells in future microfluidic systems.

  13. High power and high sensitivity PLC module using a novel corner-illuminated PIN photodiode

    Microsoft Academic Search

    Gohji Nakagawa; Seimi Sasaki; Naoki Yamamoto; Kazuhiro Tanaka; Kazunori Miura; Mitsuhiro Yano

    1997-01-01

    A high power, high sensitivity PLC module, comprising an LD and a PD surface mounted on a PLC platform, has been realized by a novel passive alignment technique. We used a spot-size transformed LD and a corner-illuminated PD to form a highly efficient optical coupling between the devices and a PLC waveguide. We used the unique marker alignment method to

  14. Ultra high resolution ultra high sensitive optical micro-angiography based on super continuum light source

    NASA Astrophysics Data System (ADS)

    An, Lin; Qin, Jia; Zhi, Zhongwei; Wang, Ruikang

    2011-03-01

    In this paper, we demonstrate for the first time utilizing a super continuum light source to achieve ultra high sensitive Optical Micro-Angiography (UHS-OMAG) system. The broad band light with central wavelength around 800nm, emitted from the super continuum light source, could provide a ~2?m coherence gate for the system. Based on a fast CMOS camera, we could successfully develop a high speed (~70 kHz line rate) Fourier Domain Optical coherence tomography system. Applying the ultra high sensitive OMAG algorithm onto the system, we could visualize blood vessel networks buried within the tissue bed in a high resolution and high sensitivity mode. The modality is performed on imaging the human finger nail fold and the mouse pinna to obtain both high resolution structure image and detailed blood perfusion map. The excellent performance shows a great potential of our system in future biological imaging application.

  15. Ultra-long high-sensitivity ?-OTDR for high spatial resolution intrusion detection of pipelines.

    PubMed

    Peng, Fei; Wu, Han; Jia, Xin-Hong; Rao, Yun-Jiang; Wang, Zi-Nan; Peng, Zheng-Pu

    2014-06-01

    An ultra-long phase-sensitive optical time domain reflectometry (?-OTDR) that can achieve high-sensitivity intrusion detection over 131.5km fiber with high spatial resolution of 8m is presented, which is the longest ?-OTDR reported to date, to the best of our knowledge. It is found that the combination of distributed Raman amplification with heterodyne detection can extend the sensing distance and enhances the sensitivity substantially, leading to the realization of ultra-long ?-OTDR with high sensitivity and spatial resolution. Furthermore, the feasibility of applying such an ultra-long ?-OTDR to pipeline security monitoring is demonstrated and the features of intrusion signal can be extracted with improved SNR by using the wavelet detrending/denoising method proposed. PMID:24921572

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

    NASA Astrophysics Data System (ADS)

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

    2015-01-01

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

  17. Metal-free tetrathienoacene sensitizers for high-performance dye-sensitized solar cells.

    PubMed

    Zhou, Nanjia; Prabakaran, Kumaresan; Lee, Byunghong; Chang, Sheng Hsiung; Harutyunyan, Boris; Guo, Peijun; Butler, Melanie R; Timalsina, Amod; Bedzyk, Michael J; Ratner, Mark A; Vegiraju, Sureshraju; Yau, Shuehlin; Wu, Chun-Guey; Chang, Robert P H; Facchetti, Antonio; Chen, Ming-Chou; Marks, Tobin J

    2015-04-01

    A new series of metal-free organic chromophores (TPA-TTAR-A (1), TPA-T-TTAR-A (2), TPA-TTAR-T-A (3), and TPA-T-TTAR-T-A (4)) are synthesized for application in dye-sensitized solar cells (DSSC) based on a donor-?-bridge-acceptor (D-?-A) design. Here a simple triphenylamine (TPA) moiety serves as the electron donor, a cyanoacrylic acid as the electron acceptor and anchoring group, and a novel tetrathienoacene (TTA) as the ?-bridge unit. Because of the extensively conjugated TTA ?-bridge, these dyes exhibit high extinction coefficients (4.5-5.2 × 10(4) M(-1) cm(-1)). By strategically inserting a thiophene spacer on the donor or acceptor side of the molecules, the electronic structures of these TTA-based dyes can be readily tuned. Furthermore, addition of a thiophene spacer has a significant influence on the dye orientation and self-assembly modality on TiO2 surfaces. The insertion of a thiophene between the ?-bridge and the cyanoacrylic acid anchoring group in TPA-TTAR-T-A (dye 3) promotes more vertical dye orientation and denser packing on TiO2 (molecular footprint = 79 Å(2)), thus enabling optimal dye loading. Using dye 3, a DSSC power conversion efficiency (PCE) of 10.1% with Voc = 0.833 V, Jsc = 16.5 mA/cm(2), and FF = 70.0% is achieved, among the highest reported to date for metal-free organic DSSC sensitizers using an I(-)/I3(-) redox shuttle. Photophysical measurements on dye-grafted TiO2 films reveal that the additional thiophene unit in dye 3 enhances the electron injection efficiency, in agreement with the high quantum efficiency. PMID:25768124

  18. Highly Sensitive Detection of Urinary Cadmium to Assess Personal Exposure

    PubMed Central

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

    2013-01-01

    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 0.25–1 ppb cadmium. PMID:23561905

  19. Sensitivity of urban hydrodynamic modelling to high resolution radar rainfall

    NASA Astrophysics Data System (ADS)

    Bruni, Guendalina; Reinoso, Ricardo; van de Giesen, Nick; Clemens, Francois; ten Veldhuis, Marie-Claire

    2014-05-01

    Since the early 90's, the need to improve the spatial and temporal resolution of rainfall estimates has been emphasised. Urban hydrological applications require high resolution rainfall inputs matching rapid response times of such catchments. With the advent of new radar technology, urban hydrologists nowadays have access to highly accurate rainfall estimates to drive their models. High resolution rainfall products are provided by dual polarimetric X-band radars, which retrieve rainfall rates at 1 min temporal resolution and 30 m spatial resolution. This study attempts to characterise sensitivity of hydrologic response to high resolution weather radar rainfall input for hydrodynamic models at urban scale. Spatial resolutions of both rainfall input and hydrologic units are of the order of 100 meters. Rainfall rates derived from X-band polarimetric weather radar are used as input into a detailed hydrodynamic sewer model for an urban catchment in Rotterdam, The Netherlands. Rainfall data of two storms, one convective and one stratiform, at different spatial resolutions, are used to analyse the effect of precipitation data resolution on simulated in-sewer water levels as well as runoff peaks. Dimensionless parameters are derived to analyse the effect of rainfall resolution in relation to storm and catchment properties. Simulation results are first analysed in relation to 'storm redistribution' induced by spatial precipitation sampling: storm correlation distance is compared to rainfall resolution and the effect on hydrodynamic model results is discussed. Sensitivity of hydrodynamic model results to storm redistribution will be discussed for varying positions throughout the catchment and dependent on localisation of convective storm cells.

  20. High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors

    NASA Astrophysics Data System (ADS)

    Kim, Kangbaek

    Optical biosensors that can precisely quantify the presence of specific molecular species in real time without the need for labeling have seen increased use in the drug discovery industry and molecular biology in general. Of the many possible optical biosensors, the TM mode Si biosensor is shown to be very attractive in the sensing application because of large field amplitude on the surface and cost effective CMOS VLSI fabrication. Noise is the most fundamental factor that limits the performance of sensors in development of high-sensitivity biosensors, and noise reduction techniques require precise studies and analysis. One such example stems from thermal fluctuations. Generally SOI biosensors are vulnerable to ambient temperature fluctuations because of large thermo-optic coefficient of silicon (˜2x10 -4 RIU/K), typically requiring another reference ring and readout sequence to compensate temperature induced noise. To address this problem, we designed sensors with a novel TM-mode shallow-ridge waveguide that provides both large surface amplitude for bulk and surface sensing. With proper design, this also provides large optical confinement in the aqueous cladding that renders the device athermal using the negative thermo-optic coefficient of water (~ --1x10-4RIU/K), demonstrating cancellation of thermo-optic effects for aqueous solution operation near 300K. Additional limitations resulting from mechanical actuator fluctuations, stability of tunable lasers, and large 1/f noise of lasers and sensor electronics can limit biosensor performance. Here we also present a simple harmonic feedback readout technique that obviates the need for spectrometers and tunable lasers. This feedback technique reduces the impact of 1/f noise to enable high-sensitivity, and a DSP lock-in with 256 kHz sampling rate can provide down to micros time scale monitoring for fast transitions in biomolecular concentration with potential for small volume and low cost. In this dissertation, a novel high-sensitivity, athermal biosensor on a TM-mode SOI resonator was designed, fabricated, and evaluated. High-performance biosensing for bulk and surface detection limits of 1x10-7 RIU and 24 fg/mm2 was demonstrated.

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

    SciTech Connect

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

    2013-09-01

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

  2. Sensitivity of once-shocked, weathered high explosives

    SciTech Connect

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

    1998-07-01

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

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

    NASA Astrophysics Data System (ADS)

    Kanwal, Shamsa; Fu, Xiaohong; Su, Xingguang

    2009-12-01

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

  4. Highly sensitive biological sensor based on photonic crystal fiber

    NASA Astrophysics Data System (ADS)

    Azzam, Shaimaa I. H.; Hameed, Mohamed F.; Obayya, S. S. A.

    2014-05-01

    A photonic crystal fiber (PCF) surface plasmon resonance (SPR) based sensor is proposed and analysed. The proposed sensor consists of microuidic slots enclosing a dodecagonal layer of air holes cladding and a central air hole. The sensor can perform analyte detection using both HEx 11 and HEy 11 modes with a relatively high sensitivities up to 4000 nm=RIU and 3000 nm=RIU and resolutions of 2.5×10-5 RIU-1 and 3.33×10-5 RIU-1 with HEx11 and HEy11, respectively, with regards to spectral interrogation which to our knowledge are higher than those reported in the literature. Moreover, the structure of the suggested sensor is simple with no fabrication complexities which makes it easy to fabricate with standard PCF fabrication technologies.

  5. Sensitivity of LHC experiments to exotic highly ionising particles

    E-print Network

    A. De Roeck; A. Katre; P. Mermod; D. Milstead; T. Sloan

    2012-05-03

    The experiments at the Large Hadron Collider (LHC) are able to discover or set limits on the production of exotic particles with TeV-scale masses possessing values of electric and/or magnetic charge such that they behave as highly ionising particles (HIPs). In this paper the sensitivity of the LHC experiments to HIP production is discussed in detail. It is shown that a number of different detection methods are required to investigate as fully as possible the charge-mass range. These include direct detection as the HIPs pass through either passive or active detectors and, in the case of magnetically charged objects, the so-called induction method with which magnetic monopoles which stop in accelerator and detector material could be observed. The benefit of using complementary approaches to HIP detection is discussed.

  6. Versatile, high-sensitivity faraday cup array for ion implanters

    DOEpatents

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

    2003-01-01

    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.

  7. Measuring ambient ozone with high sensitivity and bandwidth

    NASA Astrophysics Data System (ADS)

    Pearson, Richard, Jr.

    1990-02-01

    An ozone (O3) analyzer for use in eddy-correlation measurements is described which has an unfiltered bandwidth of at least 20 Hz and sensitivity of at least 0.1 ppbv at 12-Hz bandwidth. Based on chemiluminescence with nitric oxide, it is designed primarily for use on meteorological aircraft, but it also works well for tower measurements. It is significant that the detecting mechanism responds linearly to time-dependent inputs, which is a definite advantage for applications involving measurements of eddy fluxes and spectra O3. The unit is highly specific, the only known interference being a slight quenching of the chemiluminescence by water vapor. The unit does not respond to cloud liquid water or to precipitation, and excellent performance has been obtained in the presence of these two conditions. The entire package weighs 110 kg and requires 360 W at 110 V ac (60 or 400 Hz), and 1200 W at 28 V dc.

  8. Dewar-cooler-integrated high sensitivity MWIR wave front sensor

    NASA Astrophysics Data System (ADS)

    Velghe, Sabrina; Magli, Serge; Aubry, Gilles; Guérineau, Nicolas; Rommeluère, Sylvain; Jaeck, Julien; Wattellier, Benoit

    2013-06-01

    Recent developments in the Mid Wave InfraRed (MWIR) optical domain were made on materials, optical design and manufacturing. They answer increasing demands for more compact, less temperature dependent optical systems with increased optical performances and complexity (multi- or hyper- spectral imagery). At the same time, the characterization of these components has become strategic and requires solutions with higher performance. The optical quality of such devices is measured by wave front sensing techniques. PHASICS previously developed wave front sensors based on Quadri-Wave Lateral Shearing Interferometry (QWLSI) using broadband microbolometers cameras for infrared measurements. However they suffer from reduced light sensitivity in the MWIR domain, which limits their use with broadband sources such as black bodies. To meet metrology demands, we developed an innovative wave front sensor. This instrument combines the metrological qualities of QWLSI with the radiometric performances of a last generation detection block (Infrared Detector Dewar Cooler Assembly, IDDCA) with a quantum infrared focal plane array (IRFPA) of HgCdTe technology. The key component of QWLSI is a specific diffractive grating placed a few millimeters from the focal plane array. This requirement implies that this optics should be integrated inside the IDDCA. To achieve this, we take advantage of the experience acquired from recent developments with optics integrated in IDDCA. Thanks to this approach, we developed a high spatial resolution MWIR wave front sensor (160x128 points) with a high sensitivity for accurate measurements under low-flux conditions. This paper will present the instrument technological solutions, the development key steps and experimental results on various metrology applications.

  9. A 1-D model for highly sensitive tubular reactors

    SciTech Connect

    Hagan, P.S.; Herskowitz, M.; Pirkle, J.C.

    1987-01-01

    We consider the steady state operation of wall-cooled, fixed-bed tubular reactors. In these reactors the temperature rise ..delta..T must normally be limited to small fractions of the adiabatic temperature rise ..delta..T/sub ad/, both to avoid runaway and maintain product selectivity. Yet ..delta..T/..delta..T/sub ad/ << 1 can only occur if eta = t/sub dif//t/sub reac/ << 1, where t/sub dif/ is the timescale on which heat escapes the reactor by ''diffusing'' to the cooled walls, and t/sub reac/ is the timescale over which the reaction occurs. So here we use asymptotic methods based on eta << 1 to analyze the 2-d reactor equations, and find the radial concentration and temperature profiles to leading order in eta. We then obtain a 1-d model of the reactor by substituting these asymptotically correct profiles into the reactor equations and averaging over r. This model, the ..cap alpha..-model, is identical to the standard (Beek and Singer) 1-d model, except that the reactor's overall heat transfer coefficient U is a decreasing function of the temperature rise ..delta..T. This occurs because as ..delta..T increases, the reaction becomes increasingly concentrated near r = 0, causing a decreased heat transfer efficiency through the reactor's walls. By comparing it with numerical solutions of the original 2-d reactor equations, we find that the ..cap alpha..-model simulates the 2-d equations very accurately, even for highly sensitive reactors operated near runaway. We also find that a runaway criterion derived from the ..cap alpha..-model predicts the runaway transition of the original 2-d equations accurately, especially for highly sensitive reactors. 19 refs.

  10. Depletion of Urinary Zilpaterol Residues in Horses as Measured by ELISA and UPLC-MS/MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Three horses were dosed with dietary zilpaterol and the urine concentration measured from withdrawal day 0 to withdrawal day 21. The analyses were carried out using both enzyme linked immunosorbent assay (ELISA) and an ultra-performance liquid chromatography with triple-quadrupole-tandem mass spect...

  11. Rapid analysis of phenolic acids in beverages by UPLC–MS\\/MS

    Microsoft Academic Search

    Ji?í Gruz; Ond?ej Novák; Miroslav Strnad

    2008-01-01

    A rapid method for qualitative and quantitative analysis of 17 phenolic acids (gallic acid, 3,5-dihydroxybenzoic acid, protocatechuic acid, chlorogenic acid, gentisic acid, 4-hydroxybenzoic acid, caffeic acid, vanillic acid, syringic acid, 3-hydroxybenzoic acid, 4-coumaric acid, sinapic acid, ferulic acid, 3-coumaric acid, 2-coumaric acid, salicylic acid and trans-cinnamic acid) in different beverages was developed using ultra performance liquid chromatography (UPLC) coupled with

  12. Rapid qualitative and quantitative analysis of proanthocyanidin oligomers and polymers by UPLC-MS/MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proanthocyanidins (PAs) are a structurally complex and bioactive group of tannins. Detailed analysis of PA concentration, composition, and structure typically requires the use of one or more time-consuming analytical methods. For example, the commonly employed thiolysis and phloroglucinolysis method...

  13. A new porphyrin sensitizer with phenolic binding group for high efficiency dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Jin, Liguo; Wang, Hongjie; Wang, Shuo; Wen, Liping; Zhai, Jin; Wei, Tianxin

    2014-12-01

    A novel zinc porphyrin (5,10,15-tri-dodecoxyphenyl-20-(4-hydroxyphenyl-azo-benzenyl)-porphyrinatozinc (tdhab-ZnP)) with benzenyl-azo-phenolic group, able to adsorb on the nanocrystalline-TiO2 film, has been synthesized. We constructed a dye-sensitized solar cell based on the nanocrystalline-TiO2 hierarchical structure film, with a power conversion efficiency of 4.15 % and a high current density of 14 mA/cm2 under AM 1.5 irradiation. UV-Vis absorption spectra measurements indicated that the tdhab-ZnP molecules formed a charge transfer complex with TiO2 nanoparticles (NPs) through the phenolic group. Cyclic voltammetry measurement showed that the charge separation resulting from the tdhab-ZnP excited singlet state to the conduction band (CB) of TiO2 and charge shifting from the I-/I{3/-} couple to the porphyrin radical cation were thermodynamically feasible.

  14. High sensitivity mapping of Ti distributions in Hadean zircons

    NASA Astrophysics Data System (ADS)

    Harrison, T. Mark; Schmitt, Axel K.

    2007-09-01

    Detrital zircons as old as nearly 4.4 Ga from the Jack Hills, Western Australia, offer possible insights into a phase of Earth history for which there exists no known rock record. Ti concentrations of Hadean zircons indicate a spectrum of crystallization temperatures that range from a cluster at ca. 680 °C to apparent values exceeding 1200 °C. The low temperature peak has been interpreted to indicate the existence of 'wet' melting conditions during the Hadean, but alternate views have been advanced. We have developed methods for quantitative ion imaging of titanium in zircons using positive and negative secondary ions, produced respectively under bombardment of O - and Cs +, that permit detailed insights regarding Ti concentration distributions. Each approach has particular advantages that tradeoff in terms of sensitivity, ultimate lateral resolution, and reproducibility. Coupled with high resolution spot analyses, these ion images show that Ti contents greater than about 20 ppm in the Jack Hills zircons are associated with cracks or other crystal imperfections and that virtually all of the high apparent temperatures (i.e., > 800 °C) yet obtained are suspect for contamination by Ti extraneous to the zircon. Removing these from consideration strengthens the previous conclusion that the Hadean Jack Hills population is dominated by zircons crystallized at 680-720 °C.

  15. High-sensitivity CCD-based X-ray detector.

    PubMed

    Phillips, Walter C; Stewart, Alexander; Stanton, Martin; Naday, Istvan; Ingersoll, Charles

    2002-01-01

    The detector is designed for imaging measurements requiring relatively high sensitivity and high spatial resolution. The detector can discriminate single X-ray photons, yet has the wide dynamic range ( approximately 10000:1) associated with integrating detectors. A GdO2S2 phosphor screen converts the incoming X-ray image into an optical image. The optical image is coupled (without demagnification) to the CCD image sensor using a fiber optic faceplate. The CCD (Philips Semiconductors) has an area of 4.9 x 8.6 cm with 4000 x 7000 12 microm pixels. A single 12 keV X-ray photon produces a signal of 100 e-. With 2 x 2 pixel binning, the total noise per 24 microm pixel in a 100 s image is approximately 30 e- the detective quantum efficiency is >0.6 at 1 X-ray photon per pixel, and the full image can be read out in <4 s. The spatial resolution is 50 microm. The CCD readout system is fully computer-controlled, allowing flexible operation in time-resolved experiments. The detector has been characterized using visible-light images, X-ray images and time-resolved muscle diffraction measurements. PMID:11779944

  16. High-sensitivity thermoluminescence applied to environmental monitoring

    NASA Astrophysics Data System (ADS)

    Velbeck, K. J.; Zhang, L.; Rotunda, Joe E.; Moscovitch, Marko

    1999-02-01

    We describe the development of a new environmental TLD Dosemeter Badge and dose computation algorithm based on the new LiF:Mg,Cu,P material. LiF:Mg,Cu,P, with its high sensitivity, tissue equivalence, energy independence, and low fading characteristics, is a natural choice for environmental dosimetry. The badge consists of a card and a plastic holder. The card contains four LiF:Mg,Cu,P elements, each 3.2 mm square and 0.4 mm thick, encapsulated in TeflonR. The badge is symmetrical and uses four filters to discriminate low and high energy photons and to determine Directional Dose Equivalent, H'(0.07,(alpha) ), and Ambient Dose Equivalent, H*(10). Extensive data was taken based on irradiations of 920 dosemeters to both single and mixed fields of photons and betas. In addition, angular incidence data of various fields was taken. The approach to the algorithm is empirical and is based on this data. While most algorithms are based solely on perpendicular incidence exposure, this algorithm is being developed to account for the angular response of the dosemeter. This paper will present the algorithm for perpendicular irradiation; the angular response portion is in development. The dosemeter is designed to meet the criteria of the new draft standard ANSI N13.29, 'Environmental Dosimetry Performance -- Criteria for Testing.'

  17. High sensitivity, low power, microfabricated electrochemical sensor for CO

    SciTech Connect

    Neuzil, P.; Kayvani, D.; Maclay, G.J. [Univ. of Illinois, Chicago, IL (United States)

    1996-12-31

    CO is a toxic byproduct of incomplete combustion. Improperly vented fireplaces and faulty furnaces cause a estimated 400 deaths in the US each year. The presence of high CO levels may also indicate the presence of a fire. Hence, improved CO detection is of great interest and in the last several years commercial CO detectors have been released. The two most common methods of CO detection in commercial systems for residential use are (1) optical colorometric method, and (2) tin oxide sensor. The colorometric method has the advantage of low power, but the devices tend to give an alarm condition when exposed to low CO levels for a long time period, are difficult to reset, and have a lifetime of about 1 year. The tin oxide sensors have limited stability and high power requirement since the sensor must be heated. There is a need for a stable, sensitive, low power, low cost CO sensor. The authors have developed a planar amperometric sensor for CO detection using microfabrication technology.

  18. Highly sensitive and multiplexed platforms for allergy diagnostics

    NASA Astrophysics Data System (ADS)

    Monroe, Margo R.

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

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

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.

    1998-01-01

    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.

  20. High-Sensitivity Instrument for Measuring Atmospheric NO2

    E-print Network

    Kono, Mitsu

    the LIF instrument and a photofragmenta- tion chemiluminescence (PF-CL) instrument have been performed have been developed. The photofragmentation chemiluminescence (PF-CL) technique provides sensitive

  1. Frequency Comb Vernier Spectroscopy for Broadband, High-Resolution, High-Sensitivity Absorption and Dispersion Spectra

    Microsoft Academic Search

    Christoph Gohle; Björn Stein; Albert Schliesser; Thomas Udem; Theodor W. Hänsch

    2007-01-01

    A femtosecond frequency comb provides a vast number of equidistantly spaced narrow band laser modes that can be simultaneously tuned and frequency calibrated with 15 digit accuracy. Our Vernier spectrometer utilizes all of theses modes in a massively parallel manner to rapidly record both absorption and dispersion spectra with a sensitivity that is provided by a high finesse broadband optical

  2. Design and performance of a high-sensitivity high-resolution thermal video system

    Microsoft Academic Search

    John J. Forsthoefel; John B. Toft; Hisaaki Furuichi; Shigeyuki Komatsubara; Akira Sema

    1994-01-01

    A high sensitivity thermal video system has been jointly developed by Cincinnati Electronics Corporation and Nippon Avionics Company, Ltd. (Avio) of Japan, the TVS-8000. The system utilizes an Indium Antimonide staring focal plane array sensor, cooled by a Stirling cryocooler. The sensor\\/cooler assembly is connected to a separate video processor, display, and electronics assembly. The TVS-8000 product series offers the

  3. New methods for bandwidth enhancement of integrated high-sensitivity optical receivers

    Microsoft Academic Search

    C. Seidl; H. Dietrich; A. Nemecek; J. Knorr; R. Swoboda; H. Zimmermann

    2005-01-01

    Optoelectronic integrated circuits (OEICs) offering high bandwidth and high sensitivity as well are needed for the pickups of optical storage systems of the next generation, such as Blu-Ray or HDDVD. High bandwidth is necessary to enable high data transfer rates between the disk and the processing device, and high sensitivity allows to operate at low optical power and to deal

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

    PubMed

    Haapala, Markus; Suominen, Tina; Kostiainen, Risto

    2013-06-18

    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

  5. Sensitivity study of high eccentricity orbits for Mars gravity recovery

    NASA Astrophysics Data System (ADS)

    He, Zhi-Zhou; Huang, Cheng-Li

    2015-01-01

    By linear perturbation theory, a sensitivity study is presented to calculate the contribution of the Mars gravity field to the orbital perturbations in velocity for spacecrafts in both low eccentricity Mars orbits and high eccentricity orbits (HEOs). In order to improve the solution of some low degree/order gravity coefficients, a method of choosing an appropriate semimajor axis is often used to calculate an expected orbital resonance, which will significantly amplify the magnitude of the position and velocity perturbations produced by certain gravity coefficients. We can then assess to what degree/order gravity coefficients can be recovered from the tracking data of the spacecraft. However, this existing method can only be applied to a low eccentricity orbit, and is not valid for an HEO. A new approach to choosing an appropriate semimajor axis is proposed here to analyze an orbital resonance. This approach can be applied to both low eccentricity orbits and HEOs. This small adjustment in the semimajor axis can improve the precision of gravity field coefficients and does not affect other scientific objectives.

  6. Patternhunter Ii: Highly Sensitive and Fast Homology Search

    Microsoft Academic Search

    Ming Li; Bin Ma; Derek Kisman; John Tromp

    2004-01-01

    Extending the single optimized spaced seed of PatternHunter (20) to multiple ones, Pattern- Hunter II simultaneously remedies the lack of sensitivity of Blastn and the lack of speed of Smith- Waterman, for homology search. At Blastn speed, PatternHunter II approaches Smith-Waterman sensitivity, bringing homology search technology back to a full circle.

  7. High sensitivity metamaterial based bi-material terahertz sensor

    NASA Astrophysics Data System (ADS)

    Alves, Fabio; Grbovic, Dragoslav; Kearney, Brian; Karunasiri, Gamani

    2013-03-01

    We report on the fabrication of a microelectromechanical systems (MEMS) based bi-material terahertz (THz) detector integrated with a metamaterial structure to provide high absorption at 3.8 THz. The absorbing element of the sensor was designed with a resonant frequency that matches the quantum cascade laser illumination source, while simultaneously providing structural support, desired thermomechanical properties and optical read-out access. It consists of a periodic array of aluminum squares separated from a homogeneous aluminum (Al) ground plane by a silicon-rich silicon oxide (SiOx) layer. The absorbing element is connected to two Al/SiOx microcantilevers (legs), anchored to a silicon substrate, which acts as a heat sink, allowing the sensor to return to its unperturbed position when excitation is terminated. The metamaterial structure absorbs the incident THz radiation and transfers the heat to the legs where the significant difference between thermal expansion coefficients of Al and SiOx causes the structure to deform proportionally to the absorbed power. The amount of deformation is probed optically by measuring the displacement of a laser beam reflected on the Al ground plane of the metamaterial absorber. Measurement showed that the fabricated absorber has nearly 95% absorption at 3.8 THz. The responsivity and time constant were found to be 1.2 deg/?W and 0.65 s, respectively. The minimum detectable incident power including the readout noise is around 9 nW. The obtained high sensitivity and design flexibility indicate that sensor can be further tuned to achieve the required parameters for real time THz imaging applications.

  8. High sensitivity comparison of potential differences between two Josephson junctions

    SciTech Connect

    Tsai, J.S.

    1983-01-01

    The experimental and theoretical exactness of the Josephson voltage-frequency relation dUPSILON/dt = (2e/h)V and its relation to the accuracy of quantum electrodynamics, as well as the possible discrepancy between them are discussed. The experiment was designed to compare the electrochemical potential difference between two Josephson junctions by putting them in a DC SQUID configuration, and biasing them on a microwave induced constant-voltage step. On a step, the voltage across the junctions is determined by the applied microwave frequency v through the Josephson relation V = (h/2e) vn, where n is the order of the step. Faraday's law implies that any potential difference ..delta..V around the closed loop has to be sustained by a changing magnetic flux inside the closed loop. Thus under this condition: ((h/2e)/sub 1/ - (h/2e)/sub 2/)vn = dUPSILON/dt, so that any local dependence of the Josephson relation can be measured by monitoring the flux in the DC SQUID. The flux in the DC SQUID was measured by an RF SQUID, coupled to the DC SQUID by a superconducting flux transformer. The use of the RF SQUID and high voltage steps results in very high sensitivity of the measurement. The relative exactness of the Josephson relation between two similar junctions is established to less than one part in 10/sup 17/. This is almost one billion times better than previous results. Measurements were also made on two dissimilar junctions, namely an In microbridge and a Nb-Cu-Nb junction. For those junctions, the relative exactness is established to about two parts in 10/sup 16/. The reduced accuracy is mainly attributed to the lower biasing voltage used. The material and microscopic coupling mechanism dependence of the Josephson relation was shown to be nonexistent at this accuracy.

  9. High-sensitivity uncooled microcantilever infrared imaging arrays

    NASA Astrophysics Data System (ADS)

    Hunter, Scott R.; Amantea, Robert A.; Goodman, Lawrence A.; Kharas, David B.; Gershtein, Sergey; Matey, James R.; Perna, Steven N.; Yu, Young; Maley, Nagi; White, Lawrence K.

    2003-09-01

    The structure and operation of a new uncooled thermal infrared imaging detector is described which is composed of bimaterial, thermally sensitive microcantilever structures that are the moving elements of variable plate capacitors. The heat sensing microcantilever structures are integrated with CMOS control and amplification electronics to produce a low cost imager that is compatible with silicon IC foundry processing and materials. The bimorph sensor structure is fabricated using amorphous hydrogenated silicon carbide (a-SiC:H) as the low thermal expansion coefficient material, and gold as the high thermal expansion coefficient bimaterial (14 x 10-6/K). Amorphous hydrogenated silicon carbide is an ideal material in this application due to its very low thermal conductivity (0.34 W/m-K) and low thermal expansion coefficient (4x10-6/K). High resistivity (200-400 ?/sq) thin Ti/W films are used as the infrared resonant cavity absorber and low thermal loss electrical interconnect to the substrate electrical contacts. A temperature coefficient of capacitance, ?C/C, (equivalent to TCR for microbolometers) above 20% has been measured for these structures, and modeling of the performance of these devices indicates sensor performance in the range NETD < 5 mK and thermal time constants in the 5 -10 msec range are feasible with this technique. Our development efforts have focused on the fabrication of 320 x 240 imaging arrays with 50 micron pitch pixels. A number of these arrays have been fabricated with performance characteristics that are predicted by a detailed thermo-electro-optical-mechanical model of the sensor. The sensor design and the results from measurements of the thermo-electromechanical and optical properties of the detector arrays will be discussed.

  10. Proposed Ultra-High Sensitivity High-Frequency Gravitational Wave Detector

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.; Stephenson, Gary V.; Li, Fangyu

    2008-01-01

    The paper discusses the proposed improvement of a High-Frequency Relic Gravitational Wave (HFRGW) detector designed by Li, Baker, Fang, Stephenson and Chen in order to greatly improve its sensitivity. The improved detector is inspired by the Laser Interferometer Gravitational Observatory or LIGO, but is sensitive to the high-frequency end of the gravitational-wave spectrum. As described in prior papers it utilizes the Gertsenshtein effect, which introduces the conversion of gravitational waves to electromagnetic (EM) waves in the presence of a static magnetic field. Such a conversion, if it leads to photons moving in a direction perpendicular to the plane of the EM waves and the magnetic field, will allow for ultra-high sensitivity HFRGW detection. The use of sensitive microwave, single photon detectors such as a circuit QED and/or the Rydberg Atom Cavity Detector, or off-the-shelf detectors, could lead to such detection. When the EM-detection photons are focused at the microwave detectors by fractal-membrane reflectors sensitivity is also improved. Noise sources external to the HFRGW detector will be eliminated by placing a tight mosaic of superconducting tiles (e.g., YBCO) and/or fractal membranes on the interior surface of the detector's cryogenic containment vessel in order to provide a perfect Faraday cage. Internal thermal noise will be eliminated by means of a microwave absorbing (or reflecting) interior enclosure shaped to conform to a high-intensity continuous microwave Gaussian beam (GB), will reduce any background photon flux (BPF) noise radiated normal to the GB's axis. Such BPF will be further attenuated by a series of microwave absorbing baffles forming tunnels to the sensitive microwave detectors on each side of the GB and at right angles to the static magnetic field. A HFGW detector of bandwidth of 1 KHz to 10 KHz or less in the GHz band has been selected. It is concluded that the utilization of the new ultra-high-sensitivity microwave detectors, together with the increased microwave power and magnet intensity will allow for a detection of high-frequency gravitational waves (HFGWs) exhibiting amplitudes, A, of the time-varying spacetime strains on the order of 10-30 to 10-34.

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

    PubMed

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

    2015-01-01

    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

  12. Multi-residue and multi-class determination of antibiotics in gilthead sea bream (Sparus aurata) by ultra high-performance liquid chromatography-tandem mass spectrometry.

    PubMed

    Freitas, Andreia; Leston, Sara; Rosa, João; Castilho, Maria da Conceição; Barbosa, Jorge; Rema, Paulo; Pardal, Miguel Ângelo; Ramos, Fernando

    2014-01-01

    This paper describes a method for the determination of 41 antibiotics from seven different classes in gilthead sea bream (Sparus aurata) by ultra-high-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS). Sulfonamides, trimethoprim, tetracyclines, macrolides, quinolones, penicillins and chloramphenicol were simultaneously determined. Fourteen procedures for sample treatment were tested and an extraction with acetonitrile and ethylenediaminetetra acetic acid was found to be the best option. The methodology was validated in accordance with Decision 2002/657/EC. Precision in terms of relative standard deviation (RSD) was under 17% for all compounds, and the recoveries ranged from 92% to 111%. CC? and CC? were determined according to the maximum residue limit or the minimum required performance limit, when necessary. The validation provided evidence that the method was suitable for application in routine analysis for the detection and confirmation of antibiotics in muscle of gilthead sea bream, an important and intensively produced fish in aquaculture. PMID:24512256

  13. High sensitivity 640 x 512 (20?m pitch) microbolometer FPAs

    NASA Astrophysics Data System (ADS)

    Murphy, D. F.; Ray, M.; Kennedy, A.; Wyles, J.; Hewitt, C.; Wyles, R.; Gordon, E.; Sessler, T.; Baur, S.; Van Lue, D.; Anderson, S.; Chin, R.; Gonzalez, H.; Le Pere, C.; Ton, S.

    2006-05-01

    RVS has made a significant breakthrough in the development of a 640 × 512 array with a unit cell size of 20?m × 20 ?m and performance equivalent to that of the 25?m arrays. The successful development of this array is the first step in achieving mega-pixel formats. This FPA is designed to ultimately achieve performance near the temperature fluctuation limited NETD (<20mK, f/1, 30 Hz). The SB-300 is a highly productized readout and is designed to achieve very good sensitivity (low NETD and low spatial noise) and good dynamic range. The improved performance is through bolometer structure improvements and an innovative ROIC design. It also has a simple and flexible electrical interface which allows external electronics to be small, light, low-cost, and low-power. Almost all adjustments can be made through the serial interface; hence there is no need for external adjustable (DAC) circuitry. The improved power supply rejection helps maintain highly stable detector and strip resistor bias voltages which helps reduce spatial noise and image artifacts. We will show updated performance and imagery on these arrays, which is currently being measured at <30mK, f/1,555 30 Hz. Pixel operability is greater than 99.5% on most FPAs, where the uncorrected responsivity nonuniformity is less than 4% (sigma/mean), and time constant for these arrays was measured at <8msec. We will report detailed FPA performance results including responsivity, noise, uniformity and pixel operability. We also plan to present video imagery from the most recent FPAs. The reduction in pixel size offers several potential benefits for IR systems. For a given system resolution (IFOV) requirement, the 20 ?m pixel will allow an optical volume that is 50 % the size of a 25 ?m based system! We will also provide an update on the enhanced performance and yield producibility of our NVESD ManTech 640 × 480 25 ?m arrays, and also show data on 25 ?m arrays that have been designed for faster time constants (5 ms), while maintaining high performance. We will also show the improvement in our uncooled 320 × 240 and 640 × 480 sensor electronics in terms of reduced power and size for helmet and rifle mounted sensors.

  14. Highly sensitive and selective colorimetric sensing of antibiotics in milk.

    PubMed

    Zhang, Xiaofang; Zhang, Yang; Zhao, Hong; He, Yujian; Li, Xiangjun; Yuan, Zhuobin

    2013-05-17

    Antibiotics residues in foods are very harmful to human beings. Determination of antibiotics residues relies largely on the availability of adequate analytical techniques. Currently, there is an urgent need for on site and real time detection of antibiotics in food. In this work, a novel one step synthesis of gold nanoparticles (AuNPs) was proposed using pyrocatechol violet (PCV) as a reducer agent. Highly sensitive and selective colorimetric detection of four antibiotics kanamycin mono sulfate (KA), neomycin sulfate (NE), streptomycin sulfate (ST) and bleomycin sulfate (BL) was realized during the formation of AuNPs. PCV has -OH groups and these antibiotics have -OH, -NH2, -NH- groups, so there may be some special hydrogen-bonding interactions between PCV and these antibiotics. Therefore, the presence of KA, NE, ST and BL would influence the synthesis of AuNPs, then the color and state of AuNPs would change, which could be observed with the naked eye or a UV-vis spectrophotometer. Results showed that A670 was linear with the logarithm of KA concentration in the range from 1.0×10(-8) to 5.0×10(-7)M and 5.0×10(-7) to 5.5×10(-5)M. The detection limit of KA was 1.0×10(-9)M (S/N=3). The coexisting substances including 1.0×10(-5)M phenylalanine, alanine, glycerol, glucose, Mg(2+), Ca(2+), Na(+), K(+), CO3(2-), SO4(2-), NO3(-), Cl(-) and Br(-) did not affect the determination of 1.0×10(-7)M antibiotics. In particular, the proposed method could be applied successfully to the detection of antibiotics in the pretreated liquid milk products. PMID:23639400

  15. Stochastic sensitivity measure for mistuned high-performance turbines

    NASA Technical Reports Server (NTRS)

    Murthy, Durbha V.; Pierre, Christophe

    1992-01-01

    A stochastic measure of sensitivity is developed in order to predict the effects of small random blade mistuning on the dynamic aeroelastic response of turbomachinery blade assemblies. This sensitivity measure is based solely on the nominal system design (i.e., on tuned system information), which makes it extremely easy and inexpensive to calculate. The measure has the potential to become a valuable design tool that will enable designers to evaluate mistuning effects at a preliminary design stage and thus assess the need for a full mistuned rotor analysis. The predictive capability of the sensitivity measure is illustrated by examining the effects of mistuning on the aeroelastic modes of the first stage of the oxidizer turbopump in the Space Shuttle Main Engine. Results from a full analysis mistuned systems confirm that the simple stochastic sensitivity measure predicts consistently the drastic changes due to misturning and the localization of aeroelastic vibration to a few blades.

  16. High-sensitivity imaging with multi-mode twin beams

    E-print Network

    E. Brambilla; L. Caspani; O. Jedrkiewicz; L. A. Lugiato; A. Gatti

    2007-09-29

    Twin entangled beams produced by single-pass parametric down-conversion (PDC) offer the opportunity to detect weak amount of absorption with an improved sensitivity with respect to standard techniques which make use of classical light sources. We propose a differential measurement scheme which exploits the spatial quantum correlation of type II PDC to image a weak amplitude object with a sensitivity beyond the standard quantum limit imposed by shot-noise.

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

    PubMed Central

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

    2014-01-01

    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

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

    SciTech Connect

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

    2013-08-13

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

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

    PubMed

    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

    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

  20. SML resist processing for high-aspect-ratio and high-sensitivity electron beam lithography

    PubMed Central

    2013-01-01

    A detailed process characterization of SML electron beam resist for high-aspect-ratio nanopatterning at high sensitivity is presented. SML contrast curves were generated for methyl isobutyl ketone (MIBK), MIBK/isopropyl alcohol (IPA) (1:3), IPA/water (7:3), n-amyl acetate, xylene, and xylene/methanol (3:1) developers. Using IPA/water developer, the sensitivity of SML was improved considerably and found to be comparable to benchmark polymethylmethacrylate (PMMA) resist without affecting the aspect ratio performance. Employing 30-keV exposures and ultrasonic IPA/water development, an aspect ratio of 9:1 in 50-nm half-pitch dense grating patterns was achieved representing a greater than two times improvement over PMMA. Through demonstration of 25-nm lift-off features, the pattern transfer performance of SML is also addressed. PMID:23531370

  1. Design and performance of a high-sensitivity high-resolution thermal video system

    NASA Astrophysics Data System (ADS)

    Forsthoefel, John J.; Toft, John B.; Furuichi, Hisaaki; Komatsubara, Shigeyuki; Sema, Akira

    1994-07-01

    A high sensitivity thermal video system has been jointly developed by Cincinnati Electronics Corporation and Nippon Avionics Company, Ltd. (Avio) of Japan, the TVS-8000. The system utilizes an Indium Antimonide staring focal plane array sensor, cooled by a Stirling cryocooler. The sensor/cooler assembly is connected to a separate video processor, display, and electronics assembly. The TVS-8000 product series offers the performance advantages of combining a high sensitivity focal plane array sensor with all of the advanced features and quality of an Avio Thermal Video System (TVS) processor. This unique system offers the user a wide variety of options for real time display, analysis, and recording of thermal scenes. The design, performance, and special features of the TVS-8000 Thermal Video System will be discussed.

  2. Towards high-sensitivity and high-resolution submillimeter-wave video imaging

    Microsoft Academic Search

    Erik Heinz; Torsten May; Detlef Born; Gabriel Zieger; Solveig Anders; Viatcheslav Zakosarenko; Marco Schubert; Torsten Krause; André Krüger; Marco Schulz; Hans-Georg Meyer

    2011-01-01

    Against a background of newly emerged security threats the well-established idea of utilizing submillimeter-wave radiation for personal security screening applications has recently evolved into a promising technology. Possible application scenarios demand sensitive, fast, flexible and high-quality imaging techniques. At present, best results are obtained by passive imaging using cryogenic microbolometers as radiation detectors. Building upon the concept of a passive

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

    E-print Network

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

    2007-01-01

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

  4. Improvement in the light sensitivity of the ultrahigh-speed high-sensitivity CCD with a microlens array

    NASA Astrophysics Data System (ADS)

    Hayashida, T.,; Yonai, J.; Kitamura, K.; Arai, T.; Kurita, T.; Tanioka, K.; Maruyama, H.; Etoh, T. Goji; Kitagawa, S.; Hatade, K.; Yamaguchi, T.; Takeuchi, H.; Iida, K.

    2008-02-01

    We are advancing the development of ultrahigh-speed, high-sensitivity CCDs for broadcast use that are capable of capturing smooth slow-motion videos in vivid colors even where lighting is limited, such as at professional baseball games played at night. We have already developed a 300,000 pixel, ultrahigh-speed CCD, and a single CCD color camera that has been used for sports broadcasts and science programs using this CCD. However, there are cases where even higher sensitivity is required, such as when using a telephoto lens during a baseball broadcast or a high-magnification microscope during science programs. This paper provides a summary of our experimental development aimed at further increasing the sensitivity of CCDs using the light-collecting effects of a microlens array.

  5. Highly sensitive flexible pressure sensors with microstructured rubber dielectric layers

    NASA Astrophysics Data System (ADS)

    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

    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.

  6. Ultra high phase sensitive surface plasmon resonance biosensor

    NASA Astrophysics Data System (ADS)

    Li, Ying-Chang; Chou, Chien

    2009-02-01

    This study demonstrates a novel phase-sensitive surface plasman resonance biosensor (PS-SPRB) which is able to convert the phase modulation into amplitude modulation analytically via a differential amplifier. PS-SPRB is able to measure biomolecule interactions at ultra-low concentration relying on the properties of phase sensitive detection at shot-noise detection in a real-time. The common-phase noise-rejection mode is provided in PS-SPRB to be able to immune the background phase noise efficiently. The experimental results confirm the detection sensitivity of 0.00001 wt % concentration of sucrose solution and 10 fg/ml mouse IgG interaction with anti IgG in real time.

  7. Metal ion-organic compound for high sensitive ESR dosimetry

    PubMed

    Hassan; Ikeya

    2000-05-01

    A systematic study to find a tissue equivalent and high sensitive dosimeter material has been made to stimulate the field of ESR dosimetry. Lithium acetate dihydrate (Li-Ac.2H2O:CH3COOLi.2H2O) and lithium phosphate (Li-phosphate:Li3PO4) were irradiated by gamma-rays to study radicals with (ESR) in addition to magnesium lactate (Mg-lactate (CH3CH(OH)COO)2Mg) doped with nominal pure lithium lactate (Mg(Li)-lactate) and lithium lactate (CH3CH(OH)COOLi) doped with Mg-lactate (Li(Mg)-lactate). A triplet spectrum with intensity ratio of 1:2:1 in Li-Ac.2H2O was ascribed to acetate radical which has g = 2.0031+/-0.0004 and hyperfine splitting of A/gbeta = 2.12+/-0.1 mT. The Li-phosphate spectrum shows splitting due to anisotropic g-factors of g(parallel) = 2.0190+/-0.0005 and g(perpendicular) = 1.9974+/-0.0004. Quartet spectra with the intensity ratio of 1:3:3:1 in Mg(Li)-lactate and Li(Mg)-lactate were ascribed to lactate radicals with g-factors of 2.0032+/-0.0004 and 2.0029+/-0.0004 and the intensity ratio of 1:3:3:1 and A/gbeta = 1.92+/-0.06 and 1.82+/-0.06 mT, respectively. The response to gamma-ray dose and the thermal stability as well as the effect of UV-illumination have been studied. The obtained number of free radicals per 100 eV (G-values) were 0.4+/-0.13, 1.02+/-0.31, 1.35+/-0.35 and 0.78+/-0 for Li-Ac.2H2O, Li-phosphate, Mg(Li)-lactate, and Li(Mg)-lactate, respectively. The lifetimes were estimated from Arrhenius plots to be approximately 2.0+/-0.6, 50.7+/-20 and 10+/-3.5 years for Li-phosphate, Mg(Li)-lactate and Li(Mg)-lactate, respectively. The lifetime for Li-Ac.2H2O cannot be estimated because of the decomposition by heating. PMID:10836438

  8. A high-sensitivity push-pull magnetometer

    SciTech Connect

    Breschi, E.; Gruji?, Z. D.; Knowles, P.; Weis, A. [Department of Physics, University of Fribourg, Fribourg 1700 (Switzerland)

    2014-01-13

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

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

    SciTech Connect

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

    1980-01-01

    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.

  10. High-sensitivity and wide-directivity ultrasound detection using high Q polymer microring resonators

    PubMed Central

    Ling, Tao; Chen, Sung-Liang; Guo, L. Jay

    2011-01-01

    Small size ultrahigh Q polymer microrings working at near visible wavelength have been experimentally demonstrated as ultralow noise ultrasound detectors with wide directivity at high frequencies (>20 MHz). By combining a resist reflow and a low bias continuous etching and passivation process in mold fabrication, imprinted polymer microrings with drastically improved sidewall smoothness were obtained. An ultralow noise-equivalent pressure of 21.4 Pa over 1–75 MHz range has been achieved using a fabricated detector of 60 ?m diameter. The device’s wide acceptance angle with high sensitivity considerably benefits ultrasound-related imaging. PMID:21673832

  11. An insulin sensitizer improves the free radical defense system potential and insulin sensitivity in high fructose-fed rats

    Microsoft Academic Search

    Patrice Faure; Eliane Rossini; N. Wiernsperger; Marie Jeanne Richard; Alain Favier; Serge Halimi

    1999-01-01

    Recently there has been growing interest in the eff e c t s of antioxidants on insulin activity. In the present study, we investigated the effect of metformin on free radical activity and insulin sensitivity in high fructose-fed rats, a diet that leads to insulin resistance. The animals were divided into four groups (n = 16 per group; exper- iment

  12. AMRIS Update Ultra High Sensitivity NMR: 1-mm HTS

    E-print Network

    Weston, Ken

    .S. Edison, NHMFL/UF, Biochemistry and McKnight Brain Institute R.E. Nast, Varian, Inc. J.R. Rocca, UF, McKnight Brain Institute S. Saha, NHMFL R.S. Withers, Varian, Inc. It seems that every few months the Magnet Lab from Bruker to Varian, Inc. The overall goal of the NIH resource grant is to improve the sensitivity

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

    SciTech Connect

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

    2006-01-01

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

  14. A highly sensitive, highly reproducible laser-induced fluorescence detection system with optical pickup

    NASA Astrophysics Data System (ADS)

    Shimomura, T.; Izawa, C.; Matsui, T.

    2008-08-01

    In this study, we have developed a novel laser-induced fluorescence detection (LIF) system, which is particularly well suited for measurements in microfluidic processes such as capillary electrophoresis and microchip-based separations and in devices such as microreactors. In order to obtain a high-performance system, we have used a commercially available optical pickup head as a measurement probe along with an objective lens actuator that is vibrated in the vertical and horizontal directions of a light axis according to a simple methodology. Our system is superior to conventional systems because it has high sensitivity and high reproducibility, and it can be implemented without complex and expensive apparatus for high-precision positioning of the component and detection probe.

  15. High sensitivity gas sensor based on high-Q suspended polymer photonic crystal nanocavity

    SciTech Connect

    Clevenson, Hannah, E-mail: hannahac@mit.edu; Desjardins, Pierre; Gan, Xuetao; Englund, Dirk, E-mail: englund@mit.edu [Department of Electrical Engineering and Computer Science, Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2014-06-16

    We present high-sensitivity, multi-use optical gas sensors based on a one-dimensional photonic crystal cavity. These devices are implemented in versatile, flexible polymer materials which swell when in contact with a target gas, causing a measurable cavity length change. This change causes a shift in the cavity resonance, allowing precision measurements of gas concentration. We demonstrate suspended polymer nanocavity sensors and the recovery of sensors after the removal of stimulant gas from the system. With a measured quality factor exceeding 10{sup 4}, we show measurements of gas concentration as low as 600 parts per million (ppm) and an experimental sensitivity of 10?ppm; furthermore, we predict detection levels in the parts-per-billion range for a variety of gases.

  16. High-sensitivity Orbitrap mass analysis of intact macromolecular assemblies.

    PubMed

    Rose, Rebecca J; Damoc, Eugen; Denisov, Eduard; Makarov, Alexander; Heck, Albert J R

    2012-11-01

    The analysis of intact protein assemblies in native-like states by mass spectrometry offers a wealth of information on their biochemical and biophysical properties. Here we show that the Orbitrap mass analyzer can be used to measure protein assemblies of molecular weights approaching one megadalton with sensitivity down to the detection of single ions. Minor instrumental modifications enabled the measurement of various protein assemblies with outstanding mass-spectral resolution. PMID:23064518

  17. Low frequency, high sensitive tunable mechanical monolithic horizontal sensors

    NASA Astrophysics Data System (ADS)

    Acernese, Fausto; De Rosa, Rosario; Giordano, Gerardo; Romano, Rocco; Vilasi, Silvia; Barone, Fabrizio

    2011-04-01

    This paper describes an optimized version of the mechanical version of the monolithic tunable folded pendulum, developed at the University of Salerno, configurable both as seismometer and, in a force-feedback configuration, as accelerometer. Typical application of the sensors are in the field of geophysics, including the study of seismic and newtonian noise for characterization of suitable sites for underground interferometer for gravitational waves detection. The sensor, shaped with precision machining and electric-discharge-machining, like the previous version, is a very compact instrument, very sensitive in the low-frequency seismic noise band, with a very good immunity to environmental noises. Important characteristics are the tunability of the resonance frequency and the integrated laser optical readout, consisting of an optical lever and an interferometer. The theoretical sensitivity curves, largely improved due to a new design of the pendulum arms and of the electronics, are in a very good agreement with the measurements. The very large measurement band (10-6 +/- 10Hz) is couple to a very good sensitivity (10-12 m/?Hz in the band 0.1 +/- 10Hz), as seismometer. Prototypes of monolithic seismometers are already operational in selected sites around the world both to acquire seismic data for scientific analysis of seismic noise and to collect all the useful information to understand their performances in the very low frequency band (f < 1mHz). The results of the monolithic sensor as accelerometer (force feed-back configuration) are also presented and discussed. Particular relevance has their sensitivity that is better than 10-11 m/s2/?Hz in the band 0.1 +/- 10Hz. Finally, hypotheses are made on further developments and improvements of monolithic sensors.

  18. Ultra-high sensitive and high resolution optical coherence tomography using a laser induced electromagnetic dipole

    NASA Astrophysics Data System (ADS)

    Kuroda, Hiroto; Baba, Motoyoshi; Suzuki, Masayuki; Yoneya, Shin

    2013-09-01

    Utilizing an optical coherence tomography measurement, we have developed a technique that actively uses a dielectric response due to an induced dipole moment caused by a mode-locked pulsed laser light source. Irradiated laser light in the material induces a photo-induced electric dipole resulting in a refractive index change for its strong electric field. Using this technique, we obtained a highly sensitive fundus retina tomogram of a human eye in vivo with a resolution of 1.3 ?m by single scanning for 20 ms using 8 fs mode-locked pulse laser light with a 350 nm spread spectrum.

  19. A highly efficient and sensitive screening method for trans-activation activity of estrogen receptors

    E-print Network

    Zhao, Huimin

    describe a highly efficient and sensitive yeast-based screening method for isolating human estrogen of estrogen receptor to the growth rate of yeast cells. We used this method to screen a library of human ERaA highly efficient and sensitive screening method for trans-activation activity of estrogen

  20. A highly sensitive and specific system for large-scale gene expression profiling

    Microsoft Academic Search

    Guohong Hu; Qifeng Yang; Xiangfeng Cui; Gang Yue; Marco A Azaro; Hui-Yun Wang; Honghua Li

    2008-01-01

    BACKGROUND: Rapid progress in the field of gene expression-based molecular network integration has generated strong demand on enhancing the sensitivity and data accuracy of experimental systems. To meet the need, a high-throughput gene profiling system of high specificity and sensitivity has been developed. RESULTS: By using specially designed primers, the new system amplifies sequences in neighboring exons separated by big

  1. Agilent D1K ScreenTape and High Sensitivity D1K ScreenTape

    E-print Network

    Agilent D1K ScreenTape and High Sensitivity D1K ScreenTape Accelerate DNA analysis with the Agilent 2200 TapeStation system Automated DNA electrophoresis with scalable throughput The Agilent 2200 Tape Solution for DNA analysis · Agilent D1K ScreenTape (5067- 5361) or Agilent High Sensitivity D1K Screen

  2. A highly efficient (>6%) Cd1xMnxSe quantum dot sensitized solar cell

    E-print Network

    Cao, Guozhong

    -effective solar cell. The design and synthesis of quantum dots (QDs) for achieving high photoelectric performanceA highly efficient (>6%) Cd1Ã?xMnxSe quantum dot sensitized solar cell Jianjun Tian,*a Lili Lv,a Chengbin Fei,b Yajie Wang,b Xiaoguang Liua and Guozhong Cao*bc Quantum dot sensitized solar cells (QDSCs

  3. Design of a high-sensitivity, low-power instrument for chlorophyll a measurements

    Microsoft Academic Search

    Yi-min Yang; Kai-kai Lou; Le-chuan Zhou; Shu-ming Ye

    2010-01-01

    Detection of chlorophyll a is important in the protection of marine ecosystem. This paper focused on designing and developing a high-sensitivity, low-power instrument (Named HME Chlometer) for chlorophyll a measurements. Chlorophyll a samples of different concentration were measured, using HME Chlometer and Seapoint Chlorophyll Fluorometer for comparison, and the result showed HME Chlometer was of high sensitivity, great stability, and

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

    PubMed

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

    2014-10-01

    Babesia ovis is a tick-transmitted protozoa parasite that infects small ruminants causing fever, anaemia, hemoglobinuria, anorexia and, in acute cases, death. Common in tropical and sub-tropical areas, the presence of this parasite in sheep herds has an economic impact on industry and therefore sensitive methods for the diagnosis and disease eradication are required. To achieve this goal, a semi-nested PCR for B. ovis specific identification was developed and consequent reaction conditions and enzymes were optimized and tested with field samples. 300 blood samples from small ruminants and 39 ticks from Rhipicephalus genus were collected from different regions of Portugal. Afterwards, DNA extraction was performed and conventional and semi-nested PCR were accomplished for all samples. The results obtained from both methodologies were compared and the sensitivity was evaluated. Employing the semi-nested PCR it was possible to identify a higher number of positive cases among the evaluated samples than using the conventional PCR, namely 38/300 blood samples and 7/39 ticks. However, fragment amplification was only observed in 5 out of 300 blood samples and in none of the 39 ticks when a conventional PCR was employed. The validation of the results was achieved by sequencing the DNA fragments corresponding to the hypervariable v4 region of the 18S ribosomal RNA gene and performing an alignment with sequences already published on GenBank(®). The ticks collected in this study belong to the Rhipicephalus genus, although other species could be involved as a vector in the Babesia spread. The diagnostic assay here described is presently the most effective and sensitive method for detection of B. ovis in field blood samples and ticks, enabling the detection up to 1 parasite into 10(9) erythrocytes. PMID:25127159

  5. High order sensitivity analysis of complex, coupled systems

    NASA Technical Reports Server (NTRS)

    Sobieszczanski-Sobieski, Jaroslaw

    1990-01-01

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

  6. A low-power, high-sensitivity micromachined optical magnetometer

    NASA Astrophysics Data System (ADS)

    Mhaskar, R.; Knappe, S.; Kitching, J.

    2012-12-01

    We demonstrate an optical magnetometer based on a microfabricated 87Rb vapor cell in a micromachined silicon sensor head. The alkali atom density in the vapor cell is increased by heating the cell with light brought to the sensor through an optical fiber, and absorbed by colored filters attached to the cell windows. A second fiber-optically coupled beam optically pumps and interrogates the atoms. The magnetometer operates on 140 mW of heating power and achieves a sensitivity below 20 fT/?Hz throughout most of the frequency band from 15 Hz to 100 Hz. Such a sensor can measure magnetic fields from the human heart and brain.

  7. High sensitivity 810 GHz SIS receivers at AST/RO

    NASA Astrophysics Data System (ADS)

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

    2004-10-01

    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.

  8. Ultra-performance liquid chromatography-mass spectrometry as a sensitive and powerful technology in lipidomic applications.

    PubMed

    Zhao, Ying-Yong; Wu, Shao-Ping; Liu, Shuman; Zhang, Yongmin; Lin, Rui-Chao

    2014-09-01

    Lipidomics, the comprehensive illumination of lipid-based information in biology systems, involves in identifying lipids and profiling lipids and lipid-derived mediators. The development of lipidomics enables the characterization of lipid species and detailed lipid profiling in body fluid, tissue or cell, and allows for a wider understanding of the biological roles of lipid networks. Lipidomic research has been greatly facilitated by recent advances in ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) and involved in lipid extraction, lipid identification and data analysis supporting applications from qualitative and quantitative assessment of multiple lipid species. UPLC technique, different mass spectrometry technique, lipid extraction and data analysis in lipidomics are reviewed. Afterwards, examples are provided on the use of UPLC-MS for finding lipid biomarkers in disease, drug, food, nutrition and plant fields. We also discuss the UPLC-MS-based lipidomics for the future perspectives and their potential problems. PMID:25014415

  9. High fat diet-fed obese rats are highly sensitive to doxorubicin-induced cardiotoxicity

    SciTech Connect

    Mitra, Mayurranjan S.; Donthamsetty, Shashikiran [Department of Toxicology, College of Pharmacy, University of Louisiana at Monroe (United States); White, Brent [Cumming Veterinary Hospital, Monroe, Louisiana (United States); Mehendale, Harihara M. [Department of Toxicology, College of Pharmacy, University of Louisiana at Monroe (United States)], E-mail: mehendale@ulm.edu

    2008-09-15

    Often, chemotherapy by doxorubicin (Adriamycin) is limited due to life threatening cardiotoxicity in patients during and posttherapy. Recently, we have shown that moderate diet restriction remarkably protects against doxorubicin-induced cardiotoxicity. This cardioprotection is accompanied by decreased cardiac oxidative stress and triglycerides and increased cardiac fatty-acid oxidation, ATP synthesis, and upregulated JAK/STAT3 pathway. In the current study, we investigated whether a physiological intervention by feeding 40% high fat diet (HFD), which induces obesity in male Sprague-Dawley rats (250-275 g), sensitizes to doxorubicin-induced cardiotoxicity. A LD{sub 10} dose (8 mg doxorubicin/kg, ip) administered on day 43 of the HFD feeding regimen led to higher cardiotoxicity, cardiac dysfunction, lipid peroxidation, and 80% mortality in the obese (OB) rats in the absence of any significant renal or hepatic toxicity. Doxorubicin toxicokinetics studies revealed no change in accumulation of doxorubicin and doxorubicinol (toxic metabolite) in the normal diet-fed (ND) and OB hearts. Mechanistic studies revealed that OB rats are sensitized due to: (1) higher oxyradical stress leading to upregulation of uncoupling proteins 2 and 3, (2) downregulation of cardiac peroxisome proliferators activated receptor-{alpha}, (3) decreased plasma adiponectin levels, (4) decreased cardiac fatty-acid oxidation (666.9 {+-} 14.0 nmol/min/g heart in ND versus 400.2 {+-} 11.8 nmol/min/g heart in OB), (5) decreased mitochondrial AMP-{alpha}2 protein kinase, and (6) 86% drop in cardiac ATP levels accompanied by decreased ATP/ADP ratio after doxorubicin administration. Decreased cardiac erythropoietin and increased SOCS3 further downregulated the cardioprotective JAK/STAT3 pathway. In conclusion, HFD-induced obese rats are highly sensitized to doxorubicin-induced cardiotoxicity by substantially downregulating cardiac mitochondrial ATP generation, increasing oxidative stress and downregulating the JAK/STAT3 pathway.

  10. Carbon nanotube quantum dots as highly sensitive THz spectrometers

    NASA Astrophysics Data System (ADS)

    Rinzan, Mohamed; Jenkins, Greg; Drew, Dennis; Shafranjuk, Serhii; Barbara, Paola

    2012-02-01

    We show that carbon nanotube quantum dots (CNT-Dots) coupled to antennas are extremely sensitive, broad-band, terahertz quantum detectors. Their response is due to photon-assisted single-electron tunneling (PASET)[1], but cannot be fully understood with orthodox PASET models[2]. We consider intra-dot excitations and non-equilibrium cooling to explain the anomalous response. REFERENCES: [1] Y. Kawano, S. Toyokawa, T. Uchida and K. Ishibashi, THz photon assisted tunneling in carbon-nanotube quantum dots, Journal of Applied Physics 103, 034307 (2008). [2] P. K. Tien and J. P. Gordon, Multiphoton Process Observed in the Interaction of Microwave Fields with the Tunneling between Superconductor Films, Phys. Rev. 129, 647 (1963).

  11. High sensitivity infrared 10.6 micrometer heterodyne receiver development

    NASA Technical Reports Server (NTRS)

    1972-01-01

    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.

  12. Polycarbazole-based organic photodiodes for highly sensitive chemiluminescent immunoassays.

    PubMed

    Pires, Nuno M M; Dong, Tao

    2013-01-01

    It is reported the development of a polycarbazole-based organic photodetector for chemiluminescent immunoassays. The optical detector comprised a 1?4 blend by weight of poly [N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) and [6,6]-phenyl C71-butyric acid methyl ester (PC70BM). Optimization of the photodetector design was conducted aiming to maximize photosensitivity and reduce the background level. Quantitation of recombinant human thyroid stimulating hormone indicated good linearity and yielded a detection sensitivity of ?3.7 nA × nM(-1) and a detection limit of 80 pg/ml. PMID:24110033

  13. Highly sensitive humidity sensing properties of carbon quantum dots films

    SciTech Connect

    Zhang, Xing; Ming, Hai; Liu, Ruihua; Han, Xiao [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China)] [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Kang, Zhenhui, E-mail: zhkang@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China)] [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Liu, Yang, E-mail: yangl@suda.edu.cn [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China)] [Institute of Functional Nano and Soft Materials (FUNSOM) and Jiangsu Key Laboratory for Carbon-Based Functional Materials and Devices, Soochow University, Suzhou (China); Zhang, Yonglai, E-mail: yonglaizhang@jlu.edu.cn [Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China) [Center of Super-Diamond and Advanced Films (COSDAF), Department of Physics and Materials Science, City University of Hong Kong, Hong Kong (China); State Key Laboratory on Integrated Optoelectronics, College of Electronic Science and Engineering, Jilin University, 2699 Qianjin Street, Changchun 130012 (China)

    2013-02-15

    Graphical abstract: Display Omitted Highlights: ? A humidity sensing device was fabricated based on carbon quantum dots (CQDs) films. ? The conductivity of the CQDs films shows a linear and rapid response to atmosphere humidity. ? The humidity sensing property was due to the hydrogen bonds between the functional groups on CQDs. -- Abstract: We reported the fabrication of a humidity sensing device based on carbon quantum dots (CQDs) film. The conductivity of the CQDs film has a linear and rapid response to relative humidity, providing the opportunity for the fabrication of humidity sensing devices. The mechanism of our humidity sensor was proposed to be the formation of hydrogen bonds between carbon quantum dots and water molecules in the humidity environment, which significantly promote the electrons migration. In a control experiment, this hypothesis was confirmed by comparing the humidity sensitivity of candle soot (i.e. carbon nanoparticles) with and without oxygen containing groups on the surfaces.

  14. Highly sensitive fiber Bragg grating refractive index sensors

    NASA Astrophysics Data System (ADS)

    Liang, Wei; Huang, Yanyi; Xu, Yong; Lee, Reginald K.; Yariv, Amnon

    2005-04-01

    We combine fiber Bragg grating (FBG) technology with a wet chemical etch-erosion procedure and demonstrate two types of refractive index sensors using single-mode optical fibers. The first index sensor device is an etch-eroded single FBG with a radius of 3?m, which is used to measure the indices of four different liquids. The second index sensor device is an etch-eroded fiber Fabry-Pérot interferometer (FFPI) with a radius of ˜1.5?m and is used to measure the refractive indices of isopropyl alcohol solutions of different concentrations. Due to its narrower resonance spectral feature, the FFPI sensor has a higher sensitivity than the FBG sensor and can detect an index variation of 1.4×10-5. Since we can measure the reflection signal, these two types of sensors can be fabricated at the end of a fiber and used as point sensors.

  15. Particles and microfluidics merged: perspectives of highly sensitive diagnostic detection

    PubMed Central

    Bale, Shyam Sundhar; Bhushan, Abhinav; Shen, Keyue; Seker, Erkin; Polyak, Boris

    2014-01-01

    There is a growing need for diagnostic technologies that provide laboratories with solutions that improve quality, enhance laboratory system productivity, and provide accurate detection of a broad range of infectious diseases and cancers. Recent advances in micro- and nanoscience and engineering, in particular in the areas of particles and microfluidic technologies, have advanced the “lab-on-a-chip” concept towards the development of a new generation of point-of-care diagnostic devices that could significantly enhance test sensitivity and speed. In this review, we will discuss many of the recent advances in microfluidics and particle technologies with an eye towards merging these two technologies for application in medical diagnostics. Although the potential diagnostic applications are virtually unlimited, the most important applications are foreseen in the areas of biomarker research, cancer diagnosis, and detection of infectious microorganisms. PMID:25378716

  16. Development and validation of sensitive LC-MS/MS assays for quantification of HP-?-CD in human plasma and CSF.

    PubMed

    Jiang, Hui; Sidhu, Rohini; Fujiwara, Hideji; De Meulder, Marc; de Vries, Ronald; Gong, Yong; Kao, Mark; Porter, Forbes D; Yanjanin, Nicole M; Carillo-Carasco, Nuria; Xu, Xin; Ottinger, Elizabeth; Woolery, Myra; Ory, Daniel S; Jiang, Xuntian

    2014-05-27

    2-Hydroxypropyl-?-cyclodextrin (HP-?-CD), a widely used excipient for drug formulation, has emerged as an investigational new drug for the treatment of Niemann-Pick type C1 (NPC1) disease, a neurodegenerative cholesterol storage disorder. Development of a sensitive quantitative LC-MS/MS assay to monitor the pharmacokinetics (PKs) of HP-?-CD required for clinical trials has been challenging owing to the dispersity of the HP-?-CD. To support a phase 1 clinical trial for ICV delivery of HP-?-CD in NPC1 patients, novel methods for quantification of HP-?-CD in human plasma and cerebrospinal fluid (CSF) using LC-MS/MS were developed and validated: a 2D-LC-in-source fragmentation-MS/MS (2D-LC-IF-MS/MS) assay and a reversed phase ultra performance LC-MS/MS (RP-UPLC-MS/MS) assay. In both assays, protein precipitation and "dilute and shoot" procedures were used to process plasma and CSF, respectively. The assays were fully validated and in close agreement, and allowed determination of PK parameters for HP-?-CD. The LC-MS/MS methods are ?100-fold more sensitive than the current HPLC assay, and were successfully employed to analyze HP-?-CD in human plasma and CSF samples to support the phase 1 clinical trial of HP-?-CD in NPC1 patients. PMID:24868096

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

    SciTech Connect

    Gillette, Scott M.; Fitchorov, Trifon; Obi, Ogheneyunume; Chen, Yajie, E-mail: y.chen@neu.edu; Harris, Vincent G. [Department of Electrical and Computer Engineering, Northeastern University, Boston, Massachusetts 02115 (United States); Jiang, Liping; Hao, Hongbo; Wu, Shuangxia [Baotou Research Institute of Rare Earths, Baotou, Inner Mongolia 014030 (China)

    2014-05-07

    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.

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

    PubMed Central

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

    2014-01-01

    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

  19. Birth Weight, Current Anthropometric Markers, and High Sensitivity C-Reactive Protein in Brazilian School Children

    PubMed Central

    Pellanda, Lucia Campos

    2015-01-01

    Studies have shown associations of birth weight with increased concentrations of high sensitivity C-reactive protein. This study assessed the relationship between birth weight, anthropometric and metabolic parameters during childhood, and high sensitivity C-reactive protein. A total of 612 Brazilian school children aged 5–13 years were included in the study. High sensitivity C-reactive protein was measured by particle-enhanced immunonephelometry. Nutritional status was assessed by body mass index, waist circumference, and skinfolds. Total cholesterol and fractions, triglycerides, and glucose were measured by enzymatic methods. Insulin sensitivity was determined by the homeostasis model assessment method. Statistical analysis included chi-square test, General Linear Model, and General Linear Model for Gamma Distribution. Body mass index, waist circumference, and skinfolds were directly associated with birth weight (P < 0.001, P = 0.001, and P = 0.015, resp.). Large for gestational age children showed higher high sensitivity C-reactive protein levels (P < 0.001) than small for gestational age. High birth weight is associated with higher levels of high sensitivity C-reactive protein, body mass index, waist circumference, and skinfolds. Large for gestational age altered high sensitivity C-reactive protein and promoted additional risk factor for atherosclerosis in these school children, independent of current nutritional status. PMID:25874126

  20. Highly sensitive homogenous chemiluminescence immunoassay using gold nanoparticles as label

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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.

  1. Highly heat-sensitive luminophor for recording IR radiation

    SciTech Connect

    Zaitsev, L.M.; Martyshova, N.E.; Pospelova, L.A.; Senashenko, M.V.; Timofeev, Yu.P.

    1988-12-01

    The purpose of this study was to develop and predict the properties of a single-phase crystalline phosphor with an extended range of temperature sensitivity. The luminophors ZnS /times/ CdS mentioned above were used as a matrix to synthesize a luminophor of the new type. Substances exhibiting a different temperature dependence - Ag and Eu - were chosen for activation. The choice of the composition of the base made it possible to rely on the fact that the emission bands of both activators will mutually overlap and that a spectrally uniform crystalline phosphor will be obtained. It was shown that the dynamic range of the power density of the recorded IR radiation can be substantially expanded (up to 30). The receiving luminescent screen is made of a single-phase crystalline phosphor ZnS /times/ CdS with Ag, Eu, and Ni with thermal extinction of both centers of luminescence in different temperature regions, making it possible to obtain a series of screens with well-reproducible characteristics.

  2. High sensitivity capacitive MEMS microphone with spring supported diaphragm

    NASA Astrophysics Data System (ADS)

    Mohamad, Norizan; Iovenitti, Pio; Vinay, Thurai

    2007-12-01

    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.

  3. High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice cores

    E-print Network

    Howat, Ian M.

    High-sensitivity measurement of diverse vascular plant-derived biomarkers in high-altitude ice of diverse vascular plant- derived biomarkers in high-altitude ice cores, Geophys. Res. Lett., 36, L13501-volatile organic compounds derived from burned and fresh vascular plant sources and preserved in high- altitude ice

  4. Highly sensitive vacuum ion pump current measurement system

    DOEpatents

    Hansknecht, John Christopher (Williamsburg, VA)

    2006-02-21

    A vacuum system comprising: 1) an ion pump; 2) power supply; 3) a high voltage DC--DC converter drawing power from the power supply and powering the vacuum pump; 4) a feedback network comprising an ammeter circuit including an operational amplifier and a series of relay controlled scaling resistors of different resistance for detecting circuit feedback; 5) an optional power block section intermediate the power supply and the high voltage DC--DC converter; and 6) a microprocessor receiving feedback information from the feedback network, controlling which of the scaling resistors should be in the circuit and manipulating data from the feedback network to provide accurate vacuum measurement to an operator.

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

    PubMed Central

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

    2013-01-01

    Giardiasis, a gastrointestinal disease caused by Giardia duodenalis, is currently treated mainly with nitroimidazoles, primarily metronidazole (MTZ). Treatment failure rates of up to 20 percent reflect the compelling need for alternative treatment options. Here, we investigated whether orlistat, a drug approved to treat obesity, represents a potential therapeutic agent against giardiasis. We compared the growth inhibitory effects of orlistat and MTZ on a long-term in vitro culture adapted G. duodenalis strain, WB-C6, and on a new isolate, 14-03/F7, from a patient refractory to MTZ treatment using a resazurin assay. The giardiacidal concentration of the drugs and their combined in vitro efficacy was determined by median-effect analysis. Morphological changes after treatment were analysed by light and electron microscopy. Orlistat inhibited the in vitro growth of G. duodenalis at low micromolar concentrations, with isolate 14-03/F7 (IC5024h?=?2.8 µM) being more sensitive than WB-C6 (IC5024h?=?6.2 µM). The effect was significantly more potent compared to MTZ (IC5024h?=?4.3 µM and 11.0 µM, respectively) and led to specific undulated morphological alterations on the parasite surface. The giardiacidal concentration of orlistat was >14 µM for 14-03/F7 and >43 µM for WB-C6, respectively. Importantly, the combination of both drugs revealed no interaction on their inhibitory effects. We demonstrate that orlistat is a potent inhibitor of G. duodenalis growth in vitro and kills parasites at concentrations achievable in the gut by approved treatment regimens for obesity. We therefore propose to investigate orlistat in controlled clinical studies as a new drug in giardiasis. PMID:23977083

  6. HIGH SENSITIVITY MASS SPECTROMETRY OF THE RARE GASES

    Microsoft Academic Search

    1959-01-01

    A 60 deg sector type of mass spectrometer and associated sample ; preparation system adapted for ultrasensitive analysis of rare gas isotopic ; abundances is described. The electron bombardment ion source was designed to be ; stable over long periods wtth a high efficiency for ion production. The ; spectrometer uses a Hall crystal as a rapid method of mass

  7. High pressure-sensitive gene expression in Lactobacillus sanfranciscensis

    Microsoft Academic Search

    R. F. Vogel; M. Pavlovic; S. Hörmann; M. A. Ehrmann

    2005-01-01

    Lactobacillus sanfranciscensis is a Gram-positive lactic acid bacte- rium used in food biotechnology. It is necessary to investigate many aspects of a model organism to elucidate mechanisms of stress re- sponse, to facilitate preparation, application and performance in food fermentation, to understand mechanisms of inactivation, and to iden- tify novel tools for high pressure biotechnology. To investigate the mechanisms of

  8. High-sensitivity mass spectrometry with a tandem accelerator

    SciTech Connect

    Henning, W.

    1983-01-01

    The characteristic features of accelerator mass spectrometry are discussed. A short overview is given of the current status of mass spectrometry with high-energy (MeV/nucleon) heavy-ion accelerators. Emphasis is placed on studies with tandem accelerators and on future mass spectrometry of heavier isotopes with the new generation of higher-voltage tandems.

  9. Highly Sensitive, Mechanically Stable Nanopore Sensors for DNA Analysis

    E-print Network

    Bashir, Rashid

    molecules. The Al2O3 structures reported here exhibit enhanced mechanical properties (increased hardness, decreased stress) and improved electrical performance (low noise, high signal-to-noise ratio) over their Si, the formation of nanopores in Al2O3 membranes resulted in the localized crystallization and facetted grain

  10. PoGOLite -a high sensitivity balloon-borne

    E-print Network

    Haviland, David

    MF (~30% @ 50 keV) E Photoelectric absorption Compton scatter Array of plastic scintillators Po shield ·Orange: Side and bottom BGO (217+54 units) ·Pink: Phoswich Detector Cell (217 units) #12 (plastic) / BaSO4 (BGO) + high-Z foils 20cm NIIC, Novosibirsk Phoswich Detector Cells Side Anticoincidence

  11. Development of a Highly Sensitive Enzyme-Linked Immunosorbent Assay Based on Polyclonal

    E-print Network

    Hammock, Bruce D.

    of California, Davis, California 95616 The development of an enzyme-linked immunosorbent assay (ELISA) based-dibenzo-p-dioxin (TMDD; XVII)] which responded similarly to 2,3,7,8-TCDD in the ELISA. The most sensitive assay fromDevelopment of a Highly Sensitive Enzyme-Linked Immunosorbent Assay Based on Polyclonal Antibodies

  12. Quantitation of Rat Lacrimal Secretion: a Novel Sandwich ELISA with High Sensitivity

    E-print Network

    Quantitation of Rat Lacrimal Secretion: a Novel Sandwich ELISA with High Sensitivity SANDHYA SANGHI sensitive assay capable of monitoring tear protein secretion by small replicate cultures. To improve signi®cantly on current methods, a rat- and mouse-speci®c sandwich ELISA was developed. For this purpose, chickens

  13. Reward Sensitivity and Substance Abuse in Middle School and High School Students

    ERIC Educational Resources Information Center

    Genovese, Jeremy E. C.; Wallace, Deborah

    2007-01-01

    In this study, the authors investigated the relation between reward and punishment sensitivity and adolescent substance use. The sample (N = 216; 130 girls, 85 boys) was drawn from high school and middle school students enrolled in a Midwestern suburban school district. Participants completed a substance use questionnaire and the Sensitivity to…

  14. Hybrid Carbon Nanotubes-TiO2 Photoanodes for High Efficiency Dye-Sensitized Solar Cells

    E-print Network

    Hybrid Carbon Nanotubes-TiO2 Photoanodes for High Efficiency Dye-Sensitized Solar Cells Kadiatou, 25133 Brescia, Italy Solar Cells Laboratory, Institute of Materials Science and Technology (IMRE photoanodes for dye- sensitized solar cells (DSCs), based on nanocrystalline TiO2 with limited addition

  15. Nano-sized twins induce high rate sensitivity of flow stress in pure copper

    E-print Network

    Dao, Ming

    Nano-sized twins induce high rate sensitivity of flow stress in pure copper L. Lu a,b , R sensitivity of flow stress and the extent of strengthening in polycrystalline copper containing dif- ferent volume fractions of nano-sized twins, but having the same average grain size. The specimens were produced

  16. A Highly Sensitive, High-Throughput Assay for the Detection of Turner Syndrome

    PubMed Central

    Hager, Karl; Hosono, Seiyu; Wise, Anastasia; Li, Peining; Rinder, Henry M.; Gruen, Jeffrey R.

    2011-01-01

    Objective: Turner syndrome (TS) occurs when an X-chromosome is completely or partially deleted or when X-chromosomal mosaicism is present. Girls with TS benefit from early diagnosis and treatment with GH; however, many girls with TS are not detected until after 10 yr of age, resulting in delayed evaluation and treatment. Methods: We developed a high-throughput test for TS, based on a quantitative method of genotyping to detect X-chromosome abnormalities. This test uses pyrosequencing to quantitate relative allele strength (RAS) from single-nucleotide polymorphisms using 18 informative single-nucleotide polymorphisms markers that span the X-chromosome and one marker for the detection of Y-chromosome material. Results: Cutoff ranges for heterozygous, homozygous, or out-of-range RAS values were established from a cohort of 496 males and females. Positive TS scoring criteria were defined as the presence of homozygosity for all 18 markers or the presence of at least one out-of-range RAS value. To determine the validity of this rapid test for TS detection, we undertook a large-scale study using DNA from 132 females without TS and 74 females with TS for whom karyotypes were available. TS was identified with 96.0% sensitivity and 97.0% specificity in this cohort. We also tested buccal swab DNA from a group of 19 females without TS and 69 females with TS. In this group, TS was identified with 97.1% sensitivity and 84.2% specificity. Conclusions: These results demonstrate the validity of a high-throughput, pyrosequencing based test for the accurate detection of TS, providing a potential alternative to karyotype testing. PMID:21177792

  17. Highly Sensitive Superconducting Quantum-Interference Proximity Transistor

    NASA Astrophysics Data System (ADS)

    Ronzani, Alberto; Altimiras, Carles; Giazotto, Francesco

    2014-08-01

    We report the design and implementation of a high-performance superconducting quantum-interference proximity transistor based on aluminum-copper technology. With the adoption of a thin and short copper nanowire, we demonstrate full phase-driven modulation of the proximity-induced minigap in the normal-metal density of states. Under optimal bias, we record unprecedentedly high flux-to-voltage (up to 3 mV/?0) and flux-to-current (exceeding 100 nA/?0) transfer function values at subkelvin temperatures, where ?0 is the flux quantum. The best magnetic-flux resolution (as low as 500n?0/?Hz at 240 mK being limited by the room-temperature preamplification stage) is reached under fixed current bias. These figures of merit combined with ultralow power dissipation and micrometer-size dimensions make this mesoscopic interferometer attractive for low-temperature applications such as the investigation of the magnetization of small spin populations.

  18. Methylation-sensitive high resolution melting (MS-HRM): a new approach for sensitive and high-throughput assessment of methylation

    Microsoft Academic Search

    Tomasz K. Wojdacz; Alexander Dobrovic

    2007-01-01

    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

  19. Single-photon camera for high-sensitivity high-speed applications

    NASA Astrophysics Data System (ADS)

    Guerrieri, Fabrizio; Tisa, Simone; Tosi, Alberto; Zappa, Franco

    2010-01-01

    We present a high-speed Single-Photon Camera for demanding applications in biology, astrophysics, telecommunications, 3D imaging and security surveillance. The camera is based on a 32-by-32 array of "smart pixels" processed in a standard high-voltage technology. Every pixel is a completely independent photon-counting channel. Sensitivity is at the single-photon level and no readout noises affect the measure. The camera has high Photon-Detection Efficiency (PDE) in the blu/green visible spectrum (45% at 450 nm) and low Dark-Counting Rate (DCR) even at room temperature (usually lower than 2 kcps). The use of microlenses makes it possible to further increase the effective pixel fill-factor. The camera can be configured by means of a cross-platform user-friendly software that communicates with the camera through a fast USB link. The integration time window may range from few tens of nanoseconds to milliseconds. The maximum frame rate for the whole 1,024 pixels is about 100 kframe/s, while the minimum 20 ns dead-time between frames boosts the sensor dynamic range. The camera is equipped with a standard C-Mount connector. A gating input pin can be used to quickly gate on/off the integration. The camera works in One-Shot mode for the maximum acquisition speed, Real-Time mode for very long measurements and Live mode for setups alignment purposes.

  20. A novel high resolution, high sensitivity SPECT detector for molecular imaging of cardiovascular diseases

    NASA Astrophysics Data System (ADS)

    Cusanno, F.; Argentieri, A.; Baiocchi, M.; Colilli, S.; Cisbani, E.; De Vincentis, G.; Fratoni, R.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Lucentini, M.; Magliozzi, M. L.; Majewski, S.; Marano, G.; Musico, P.; Musumeci, M.; Santavenere, F.; Torrioli, S.; Tsui, B. M. W.; Vitelli, L.; Wang, Y.

    2010-05-01

    Cardiovascular diseases are the most common cause of death in western countries. Understanding the rupture of vulnerable atherosclerotic plaques and monitoring the effect of innovative therapies of heart failure is of fundamental importance. A flexible, high resolution, high sensitivity detector system for molecular imaging with radionuclides on small animal models has been designed for this aim. A prototype has been built using tungsten pinhole and LaBr3(Ce) scintillator coupled to Hamamatsu Flat Panel PMTs. Compact individual-channel readout has been designed, built and tested. Measurements with phantoms as well as pilot studies on mice have been performed, the results show that the myocardial perfusion in mice can be determined with sufficient precision. The detector will be improved replacing the Hamamatsu Flat Panel with Silicon Photomultipliers (SiPMs) to allow integration of the system with MRI scanners. Application of LaBr3(Ce) scintillator coupled to photosensor with high photon detection efficiency and excellent energy resolution will allow dual-label imaging to monitor simultaneously the cardiac perfusion and the molecular targets under investigation during the heart therapy.

  1. Purification of ethanol for highly sensitive self-assembly experiments

    PubMed Central

    Barbe, Kathrin; Kind, Martin; Pfeiffer, Christian

    2014-01-01

    Summary Ethanol is the preferred solvent for the formation of self-assembled monolayers (SAMs) of thiolates on gold. By applying a thin film sensor system, we could demonstrate that even the best commercial qualities of ethanol contain surface-active contaminants, which can compete with the desired thiolates for surface sites. Here we present that gold nanoparticles deposited onto zeolite X can be used to remove these contaminants by chemisorption. This nanoparticle-impregnated zeolite does not only show high capacities for surface-active contaminants, such as thiols, but can be fully regenerated via a simple pyrolysis protocol. PMID:25161861

  2. Dynamics and sensitivity analysis of high-frequency conduction block

    NASA Astrophysics Data System (ADS)

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

    2011-10-01

    The local delivery of extracellular high-frequency stimulation (HFS) has been shown to be a fast acting and quickly reversible method of blocking neural conduction and is currently being pursued for several clinical indications. However, the mechanism for this type of nerve block remains unclear. In this study, we investigate two hypotheses: (1) depolarizing currents promote conduction block via inactivation of sodium channels and (2) the gating dynamics of the fast sodium channel are the primary determinate of minimal blocking frequency. Hypothesis 1 was investigated using a combined modeling and experimental study to investigate the effect of depolarizing and hyperpolarizing currents on high-frequency block. The results of the modeling study show that both depolarizing and hyperpolarizing currents play an important role in conduction block and that the conductance to each of three ionic currents increases relative to resting values during HFS. However, depolarizing currents were found to promote the blocking effect, and hyperpolarizing currents were found to diminish the blocking effect. Inward sodium currents were larger than the sum of the outward currents, resulting in a net depolarization of the nodal membrane. Our experimental results support these findings and closely match results from the equivalent modeling scenario: intra-peritoneal administration of the persistent sodium channel blocker ranolazine resulted in an increase in the amplitude of HFS required to produce conduction block in rats, confirming that depolarizing currents promote the conduction block phenomenon. Hypothesis 2 was investigated using a spectral analysis of the channel gating variables in a single-fiber axon model. The results of this study suggested a relationship between the dynamical properties of specific ion channel gating elements and the contributions of corresponding conductances to block onset. Specifically, we show that the dynamics of the fast sodium inactivation gate are 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 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.

  3. A compact high-sensitivity heterodyne interferometer for industrial metrology

    NASA Astrophysics Data System (ADS)

    Schuldt, Thilo; Gohlke, Martin; Weise, Dennis; Peters, Achim; Johann, Ulrich; Braxmaier, Claus

    2008-04-01

    For translation and tilt metrology, we developed a compact fiber-coupled polarizing heterodyne interferometer which is based on a highly symmetric design where both, measurement and reference beam have similar optical pathlengths and the same frequency and polarization. The method of differential wavefront sensing is implemented for tilt measurement. With this setup we reached noise levels below 5 pm/square root of Hz; Hz in translation and below 10 nrad/square root of Hz; in tilt measurement, both for frequencies above 10-2 Hz. While this setup is developed with respect to the requirements of the LISA (Laser Interferometer Space Antenna) space mission, we here present the current status of its adoption to industrial applications. We currently design a very compact and quasi-monolithic setup of the interferometer sensor head based on ultra-low expansion glass material. The resulting compact and robust sensor head can be used for nano-positioning control. We also plan to implement a scan of the measurement beam over the surface under investigation enabling high resolution 3D profilometry and surface property measurements (i. e. roughness, evenness and roundness). The dedicated low-noise (<=1nm/square root of Hz) piezo-electric actuator in the measurement beam of the interferometer will be realized using integrated micro-system technology and can either be implemented in one or two dimensions.

  4. Development of a 300,000-pixel ultrahigh-speed high-sensitivity CCD

    NASA Astrophysics Data System (ADS)

    Ohtake, H.; Hayashida, T.; Kitamura, K.; Arai, T.; Yonai, J.; Tanioka, K.; Maruyama, H.; Etoh, T. Goji; Poggemann, D.; Ruckelshausen, A.; van Kuijk, H.; Bosiers, Jan T.

    2006-02-01

    We are developing an ultrahigh-speed, high-sensitivity broadcast camera that is capable of capturing clear, smooth slow-motion videos even where lighting is limited, such as at professional baseball games played at night. In earlier work, we developed an ultrahigh-speed broadcast color camera1) using three 80,000-pixel ultrahigh-speed, highsensitivity CCDs2). This camera had about ten times the sensitivity of standard high-speed cameras, and enabled an entirely new style of presentation for sports broadcasts and science programs. Most notably, increasing the pixel count is crucially important for applying ultrahigh-speed, high-sensitivity CCDs to HDTV broadcasting. This paper provides a summary of our experimental development aimed at improving the resolution of CCD even further: a new ultrahigh-speed high-sensitivity CCD that increases the pixel count four-fold to 300,000 pixels.

  5. 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...

  6. A Newly Developed Radio Frequency Wireless Passive Highly Sensitive Strain Transducer

    E-print Network

    Tentzeris, Manos

    A Newly Developed Radio Frequency Wireless Passive Highly Sensitive Strain Transducer Trang T. Thai Toulouse Cedex 4, France trang.thai@gatech.edu Trang T. Thai, Manos. M. Tentzeris School of ECE, Georgia

  7. High Temperature and High Sensitive NOx Gas Sensor with Pt\\/SnO2\\/SiC\\/Ni Heterojunction Structure

    Microsoft Academic Search

    Gao Wei; Shabbir A. Khan; Liqin Shi; Yuki Hasegawa; Teruaki Katsube

    2005-01-01

    In order to develop a high temperature (200°C˜400°C) and high sensitive NOx gas sensor with SiC based junction structure, a hetero-junction structure, Pt\\/SnO2\\/SiC\\/Ni, was investigated and compared with the catalytic metal gate Schottky structure (Pt\\/SiC\\/Ni) sensor. It was found that the hetero-junction device showed much higher sensitivity to NO2 gas compared with the Schottky junction structure sensor, whereas Schottky structure

  8. Impact sensitivity of materials in contact with liquid and gaseous oxygen at high pressure

    NASA Technical Reports Server (NTRS)

    Schwinghamer, R. J.

    1972-01-01

    As a result of the Apollo 13 incident, increased emphasis is being placed on materials compatibility in a high pressure GOX environment. It is known that in addition to impact sensitivity of materials, approximately adiabatic compression conditions can contrive to induce materials reactivity. Test runs at high pressure using the ABMA tester indicate the following: (1) The materials used in the tests showed an inverse relationship between thickness and impact sensitivity. (2) Several materials tested exhibited greater impact sensitivity in GOX than in LOX. (3) The impact sensitivity of the materials tested in GOX, at the pressures tested, showed enhanced impact sensitivity with higher pressure. (4) The rank ordering of the materials tested in LOX up to 1000 psia is the same as the rank ordering resulting from tests in LOX at 14.7 psia.

  9. Confidence Level and Sensitivity Limits in High Contrast Imaging

    E-print Network

    Marois, C; MacIntosh, B; Doyon, R

    2007-01-01

    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 confi...

  10. Construction of multidrug-sensitive yeast with high sporulation efficiency.

    PubMed

    Chinen, Takumi; Ota, Yu; Nagumo, Yoko; Masumoto, Hiroshi; Usui, Takeo

    2011-01-01

    Budding yeast is often used in chemical genetics for screening, target identification, and compound verification, but its high-level drug resistance has made the analysis of compounds difficult. Here we report the construction of 12gene?0HSR, a strain that lacks eight efflux pumps located on the plasma membrane and four transcription factors involved in expression of efflux pumps, and contains the RME1(ins-308A) mutation. This strain retained sufficient transformation, mating, and sporulation efficiency for genetic analysis in addition to hypersensitivity against several compounds. 12gene?0HSR is a useful tool for chemical biology, not only in chemical screening but in target identification and verification of bioactive compounds. PMID:21821930

  11. Stretchable and highly sensitive graphene-on-polymer strain sensors

    PubMed Central

    Li, Xiao; Zhang, Rujing; Yu, Wenjian; Wang, Kunlin; Wei, Jinquan; Wu, Dehai; Cao, Anyuan; Li, Zhihong; Cheng, Yao; Zheng, Quanshui; Ruoff, Rodney S.; Zhu, Hongwei

    2012-01-01

    The use of nanomaterials for strain sensors has attracted attention due to their unique electromechanical properties. However, nanomaterials have yet to overcome many technological obstacles and thus are not yet the preferred material for strain sensors. In this work, we investigated graphene woven fabrics (GWFs) for strain sensing. Different than graphene films, GWFs undergo significant changes in their polycrystalline structures along with high-density crack formation and propagation mechanically deformed. The electrical resistance of GWFs increases exponentially with tensile strain with gauge factors of ~103 under 2~6% strains and ~106 under higher strains that are the highest thus far reported, due to its woven mesh configuration and fracture behavior, making it an ideal structure for sensing tensile deformation by changes in strain. The main mechanism is investigated, resulting in a theoretical model that predicts very well the observed behavior. PMID:23162694

  12. Method for rapid, high sensitivity tritiated water extraction

    SciTech Connect

    Failor, R.; Belovodsky, L.; Gaevoy, V.; Golubev, A.

    1997-04-20

    We have developed a thermal vacuum desorption process to rapidly extract water from environmental samples for tritium analysis. Thermal vacuum desorption allows for extraction of the moisture from the sample within a few hours in a form and quantity suitable for liquid scintillation counting and allows detection of tritium at the levels of <2 Bq/L of milk, <0.5 Bq/gm of vegetation, and < 0.5 Bq/gin of soil. We developed a prototype unit that can process batches of twenty or more samples within 24 hours. Early data shows that a high percentage of water is extracted reproducibly without enrichment or depletion of the tritium content. The quench coefficient of the extracted water is low allowing for accurate, direct liquid scintillation counting. Excellent comparison has been observed with results using freeze-dry lypholization as the water extraction method.

  13. A new readout circuit for an ultra high sensitivity CMOS image sensor

    Microsoft Academic Search

    T. Watabe; M. Goto; H. Ohtake; H. Maruyama; K. Tanioka

    2002-01-01

    We have developed a new readout circuit for highly sensitive CMOS image sensors. The circuit makes it possible to obtain high signal-to-noise ratio (S\\/N) by effectively transferring signal charges accumulated in the photo-diode (PD) to a smaller capacitance. We fabricated and tested a CMOS image sensor with the readout circuit, and confirmed that it has higher sensitivity than conventional passive-type

  14. A sensitive colorimetric high-throughput screening method for lipase synthetic activity assay.

    PubMed

    Zheng, Jianyong; Fu, Xianfeng; Ying, Xiangxian; Zhang, Yinjun; Wang, Zhao

    2014-05-01

    A sensitive and practical high-throughput screening method for assaying lipase synthetic activity is described. Lipase-catalyzed transesterification between vinyl acetate and n-butanol in n-hexane was chosen as a model reaction. The released acetaldehyde was determined by the colorimetric method using 3-methyl-2-benzothialinone (MBTH) derivatization. In comparison with other methods, the major advantages of this process include high sensitivity, simple detection, inexpensive reagents, and low requirements for instruments. PMID:24525041

  15. Highly sensitive differential tomographic technique for real-time ultrashort pulse characterization.

    PubMed

    Kang, Inuk; Dorrer, Christophe

    2005-06-15

    We demonstrate a highly sensitive real-time optical pulse characterization technique based on differential chronocyclic tomography. The spectral intensity and phase of the pulse under test are reconstructed analytically from two experimental traces measured simultaneously in the spectral domain. The high sensitivity and accuracy are made possible by lock-in detection of the differential spectra in the simplified chronocyclic tomography. An accuracy of approximately 0.04 rad of spectral phase recovery is achieved with a 10-Hz refresh rate and 10-microW sensitivity. We also show that the measurement technique is applicable to pulses as short as approximately 100 fs. PMID:16007802

  16. Ultra-highly sensitive surface-corrugated microfiber Bragg grating force sensor

    NASA Astrophysics Data System (ADS)

    Luo, Wei; Kou, Jun-long; Chen, Ye; Xu, Fei; Lu, Yan-qing

    2012-09-01

    We experimentally demonstrate a microfiber Bragg grating force sensor with ultra-high sensitivity. The fiber Bragg grating (FBG) is inscribed in a microfiber tapered from standard non-photosensitive single-mode fiber by focused ion beam machining method, and has a compact size (˜112 ?m in length). Small diameter increases the force sensitivity of such grating when acting as a force-sensing element under tensile loads. We have demonstrated force sensitivity as high as ˜3146 nm/N around the resonant wavelength of 1538 nm, which is three orders of magnitude larger than FBGs in untapered fibers.

  17. Human cortical sensitivity to interaural level differences in low- and high-frequency sounds.

    PubMed

    Salminen, Nelli H

    2015-02-01

    Interaural level difference (ILD) is used as a cue in horizontal sound source localization. In free field, the magnitude of ILD depends on frequency: it is more prominent at high than low frequencies. Here, a magnetoencephalography experiment was conducted to test whether the sensitivity of the human auditory cortex to ILD is also frequency-dependent. Robust cortical sensitivity to ILD was found that could not be explained by monaural level effects, but this sensitivity did not differ between low- and high-frequency stimuli. This is consistent with previous psychoacoustical investigations showing that performance in ILD discrimination is not dependent on frequency. PMID:25698049

  18. Highly Sensitive Nanoparticle-based Multifunctional Biosensor for Antigen Detection

    NASA Astrophysics Data System (ADS)

    Siavoshi, Salome

    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.

  19. Confidence Level and Sensitivity Limits in High Contrast Imaging

    SciTech Connect

    Marois, C

    2007-11-07

    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.

  20. Confidence Level and Sensitivity Limits in High Contrast Imaging

    SciTech Connect

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

    2008-06-02

    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.

  1. Confidence Level and Sensitivity Limits in High Contrast Imaging

    E-print Network

    C. Marois; D. Lafreniere; B. Macintosh; R. Doyon

    2007-09-21

    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 5sigma 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*10^-7 confidence level detection threshold when averaging a partially correlated non-Gaussian noise.

  2. [Lewis lung carcinoma variant with high sensitivity to antitumor antiangiogenic therapy reveals a high capacity to autophagy].

    PubMed

    Kolesnyk, D L; Piaskovs'ka, O M; Tregubova, N A; Solianyk, H I

    2012-01-01

    Comparative investigation of two variants of Lewis lung carcinoma cells (LLC and LLC/R9) growing under nutrient deficiency caused by long-term incubation without growth medium replacement was performed. It was established that LLC/R9 cells which in contrast to LLC cells had a high sensitivity to antitumor antiangiogenic therapy (AAT) revealed a high dependence of their survival from glucose level in growth medium as well as high capacity to autophagy under nutrient deficiency. Perhaps high autophagy activity in tumor cells may be considered as a marker of tumor AAT sensitivity. PMID:22856144

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

    PubMed

    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

    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

  4. Coupled Aerodynamic and Structural Sensitivity Analysis of a High-Speed Civil Transport

    NASA Technical Reports Server (NTRS)

    Mason, B. H.; Walsh, J. L.

    2001-01-01

    An objective of the High Performance Computing and Communication Program at the NASA Langley Research Center is to demonstrate multidisciplinary shape and sizing optimization of a complete aerospace vehicle configuration by using high-fidelity, finite-element structural analysis and computational fluid dynamics aerodynamic analysis. In a previous study, a multi-disciplinary analysis system for a high-speed civil transport was formulated to integrate a set of existing discipline analysis codes, some of them computationally intensive, This paper is an extension of the previous study, in which the sensitivity analysis for the coupled aerodynamic and structural analysis problem is formulated and implemented. Uncoupled stress sensitivities computed with a constant load vector in a commercial finite element analysis code are compared to coupled aeroelastic sensitivities computed by finite differences. The computational expense of these sensitivity calculation methods is discussed.

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

    PubMed Central

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

    2014-01-01

    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

  6. Toward high-sensitivity and high-resolution submillimeter-wave video imaging

    NASA Astrophysics Data System (ADS)

    Heinz, Erik; May, Torsten; Born, Detlef; Zieger, Gabriel; Thorwirth, Günter; Anders, Solveig; Zakosarenko, Vyacheslav; Krause, Torsten; Krüger, André; Schulz, Marco; Meyer, Hans-Georg; Schubert, Marco; Starkloff, Michael

    2011-11-01

    Against a background of newly emerged security threats, the well-established idea of utilizing submillimeter-wave radiation for personal security screening applications has recently evolved into a promising technology. Possible application scenarios demand sensitive, fast, flexible and high-quality imaging techniques. At present, best results are obtained by passive imaging using cryogenic microbolometers as radiation detectors. Building upon the concept of a passive submillimeter-wave stand-off video camera introduced previously, we present the evolution of this concept into a practical application-ready imaging device. This has been achieved using a variety of measures such as optimizing the detector parameters, improving the scanning mechanism, increasing the sampling speed, and enhancing the image generation software. The camera concept is based on a Cassegrain-type mirror optics, an optomechanical scanner, an array of 20 superconducting transition-edge sensors operated at a temperature of 450 to 650 mK, and a closed-cycle cryogen-free cooling system. The main figures of the system include: a frequency band of 350+/-40 GHz, an object distance of 7 to 10 m, a circular field of view of 1.05 m diameter, and a spatial resolution in the image center of 2 cm at 8.5 m distance, a noise equivalent temperature difference of 0.1 to 0.4 K, and a maximum frame rate of 10 Hz.

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

    PubMed

    Ashby, Casey R; Stritzke, Werner G K

    2013-08-01

    Two experiments examined the effect of positive and negative priming on implicit approach and avoidance inclinations toward high-fat food stimuli in participants high or low in reward sensitivity, using personalized unipolar variants of the Implicit Association Test (IAT; A. G. Greenwald, D. E. McGhee, & J. L. K. Schwartz, 1998, "Measuring individual differences in implicit cognition: The Implicit Association Test," Journal of Personality and Social Psychology, Vol. 74, pp. 1464-1480). Participants high in reward sensitivity showed an automatic processing bias that is characterized by a dual vulnerability of being particularly susceptible to priming of the rewarding aspects of high-fat foods, while being unaffected by priming of the negative aspects of those foods. In contrast, participants low in reward sensitivity generally showed no facilitation of implicit-approach inclinations following positive priming, but consistently showed facilitation of implicit-avoidance inclinations following negative priming. These results are consistent with the revised reinforcement sensitivity theory ( J. A. Gray & N. McNaughton, 2000, The neuropsychology of anxiety: An enquiry into the functions of the septo-hippocampal system, 2nd ed., New York, NY, Oxford University Press.) and suggest that the systems mediating reward sensitivity and punishment sensitivity are not orthogonal, as predicted by the separable subsystems hypothesis, but can be interdependent, as predicted by the joint subsystems hypothesis. PMID:23527505

  8. Slow light engineering for high Q high sensitivity photonic crystal microcavity biosensors in silicon.

    PubMed

    Chakravarty, Swapnajit; Zou, Yi; Lai, Wei-Cheng; Chen, Ray T

    2012-01-01

    Current trends in photonic crystal microcavity biosensors in silicon-on-insulator (SOI), that focus on small and smaller sensors have faced a bottleneck trying to balance two contradictory requirements of resonance quality factor and sensitivity. By simultaneous control of the radiation loss and optical mode volumes, we show that both requirements can be satisfied simultaneously. Microcavity sensors are designed in which resonances show highest Q ? 9300 in the bio-ambient phosphate buffered saline (PBS) as well as highest sensitivity among photonic crystal biosensors. We experimentally demonstrated mass sensitivity 8.8 atto-grams with sensitivity per unit area of 0.8 pg/mm(2). Highest sensitivity, irrespective of the dissociation constant K(d), is demonstrated among all existing label-free optical biosensors in silicon at the concentration of 0.1 ?g/ml. PMID:22748964

  9. Slow light engineering for high Q high sensitivity photonic crystal microcavity biosensors in silicon

    PubMed Central

    Chakravarty, Swapnajit; Zou, Yi; Lai, Wei-Cheng; Chen, Ray T.

    2012-01-01

    Current trends in photonic crystal microcavity biosensors in silicon-on-insulator (SOI), that focus on small and smaller sensors have faced a bottleneck trying to balance two contradictory requirements of resonance quality factor and sensitivity. By simultaneous control of the radiation loss and optical mode volumes, we show that both requirements can be satisfied simultaneously. Microcavity sensors are designed in which resonances show highest Q ~9,300 in the bio-ambient phosphate buffered saline (PBS) as well as highest sensitivity among photonic crystal biosensors. We experimentally demonstrated mass sensitivity 8.8 atto-grams with sensitivity per unit area of 0.8 picograms/mm2 Highest sensitivity, irrespective of the dissociation constant Kd, is demonstrated among all existing label-free optical biosensors in silicon at the concentration of 0.1?g/ml. PMID:22748964

  10. Clinical comparison of high-resolution with high-sensitivity collimators in low-count cardiac gated blood pool studies

    SciTech Connect

    Kuni, C.C.; Johnson, T.K.; Boudreau, R.J.

    1988-01-01

    We compared high-sensitivity (HS) and high-resolution (HR) collimators for 2.5-minute low-count acquisitions in 13 patients undergoing cardiac gated blood pool studies. High-count acquisitions served as standards. Ejection fractions calculated from low-count acquisitions were plotted against high-count acquisitions for each collimator; the variance of the HS plot was lower, and HS images were superior.

  11. High-sensitivity and high-Q-factor glass photonic crystal cavity and its applications as sensors.

    PubMed

    Siraji, Ashfaqul Anwar; Zhao, Yang

    2015-04-01

    We investigate the properties of a planar photonic crystal cavity on glass and its applications as sensors. An airbridged twofold defect cavity on Schott glass background and Gorilla glass substrate has been designed for high Q-factor up to 4459. The average sensitivity of the cavity resonance to background refractive index is 388 nm/Refractive Index Unit. The resonant wavelength is sensitive to background temperature by 18.5 pm/°C. The designed sensors show much higher sensitivity than those based on waveguide interferometers or photonic bandgap structures without cavity resonance. The results are also useful for experimental studies of glass photonic devices. PMID:25831371

  12. A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance.

    PubMed

    Wang, Xianfeng; Ding, Bin; Yu, Jianyong; Wang, Moran; Pan, Fukui

    2010-02-01

    A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log(Deltaf) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability. PMID:20023313

  13. A highly sensitive humidity sensor based on a nanofibrous membrane coated quartz crystal microbalance

    NASA Astrophysics Data System (ADS)

    Wang, Xianfeng; Ding, Bin; Yu, Jianyong; Wang, Moran; Pan, Fukui

    2010-02-01

    A novel humidity sensor was fabricated by electrospinning deposition of nanofibrous polyelectrolyte membranes as sensitive coatings on a quartz crystal microbalance (QCM). The results of sensing experiments indicated that the response of the sensors increased by more than two orders of magnitude with increasing relative humidity (RH) from 6 to 95% at room temperature, exhibiting high sensitivity, and that, in the range of 20-95% RH, the Log(?f) showed good linearity. The sensitivity of fibrous composite polyacrylic acid (PAA)/poly(vinyl alcohol) (PVA) membranes was two times higher than that of the corresponding flat films at 95% RH. Compared with fibrous PAA/PVA membranes, the nanofibrous PAA membranes exhibited remarkably enhanced humidity sensitivity due to their high PAA content and large specific surface area caused by the formation of ultrathin nanowebs among electrospun fibers. Additionally, the resultant sensors exhibited a good reversible behavior and good long term stability.

  14. Suppression of Sensitivity to Drugs and Antibiotics by High External Cation Concentrations in Fission Yeast

    PubMed Central

    Shabro, Aidin; Sunnerhagen, Per

    2015-01-01

    Background Potassium ion homeostasis plays an important role in regulating membrane potential and therefore resistance to cations, antibiotics and chemotherapeutic agents in Schizosaccharomyces pombe and other yeasts. However, the precise relationship between drug resistance in S. pombe and external potassium concentrations (particularly in its natural habitats) remains unclear. S. pombe can tolerate a wide range of external potassium concentrations which in turn affect plasma membrane polarization. We thus hypothesized that high external potassium concentrations suppress the sensitivity of this yeast to various drugs. Methods We have investigated the effect of external KCl concentrations on the sensitivity of S. pombe cells to a wide range of antibiotics, antimicrobial agents and chemotherapeutic drugs. We employed survival assays, immunoblotting and microscopy for these studies. Results We demonstrate that KCl, and to a lesser extent NaCl and RbCl can suppress the sensitivity of S. pombe to a wide range of antibiotics. Ammonium chloride and potassium hydrogen sulphate also suppressed drug sensitivity. This effect appears to depend in part on changes to membrane polarization and membrane transport proteins. Interestingly, we have found little relationship between the suppressive effect of KCl on sensitivity and the structure, polarity or solubility of the various compounds investigated. Conclusions High concentrations of external potassium and other cations suppress sensitivity to a wide range of drugs in S. pombe. Potassium-rich environments may thus provide S. pombe a competitive advantage in nature. Modulating potassium ion homeostasis may sensitize pathogenic fungi to antifungal agents. PMID:25793410

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

    NASA Astrophysics Data System (ADS)

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

    2008-09-01

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2014-10-01

    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 1.33–1.44, and the average sensitivity of 9295 nm/RIU in an RI range from 1.44 to 1.54 can be obtained.

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

    Microsoft Academic Search

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

    2000-01-01

    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 400–600nm to electrons. A high incident photon-to-current efficiency (IPCE), 69%, was obtained at 510nm

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

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

    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.

  19. Fabrication of a Highly Sensitive Chemical Sensor Based on ZnO Nanorod Arrays

    PubMed Central

    2010-01-01

    We report a novel method for fabricating a highly sensitive chemical sensor based on a ZnO nanorod array that is epitaxially grown on a Pt-coated Si substrate, with a top–top electrode configuration. To practically test the device, its O2 and NO2 sensing properties were investigated. The gas sensing properties of this type of device suggest that the approach is promising for the fabrication of sensitive and reliable nanorod chemical sensors. PMID:20672125

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

    Microsoft Academic Search

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

    2006-01-01

    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

  1. Sensitivity of High-Resolution Simulations of Hurricane Bob (1991) to Planetary Boundary Layer Parameterizations

    Microsoft Academic Search

    Scott A. Braun; Wei-Kuo Tao

    2000-01-01

    The fifth-generation Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model is used to simulate Hurricane Bob (1991) using grids nested to high resolution (4 km). Tests are conducted to determine the sensitivity of the simulation to the available planetary boundary layer parameterizations, including the bulk aerodynamic, Blackadar, Medium-Range Forecast (MRF) model, and Burk-Thompson bound- ary layer schemes. Significant sensitivity

  2. Polycrystalline CVD diamond detector: Fast response and high sensitivity with large area

    SciTech Connect

    Liu, Linyue, E-mail: liulinyue@gmail.com; Zhang, Xianpeng; Zhong, Yunhong [Northwest Institute of Nuclear Technology, Xi'an 710024 (China)] [Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Ouyang, Xiaoping, E-mail: oyxp@yahoo.com; Zhang, Jianfu [Northwest Institute of Nuclear Technology, Xi'an 710024 (China) [Northwest Institute of Nuclear Technology, Xi'an 710024 (China); Xi'an Jiaotong University, Xi'an 710049 (China)

    2014-01-15

    Polycrystalline diamond was successfully used to fabricate a large area (diameter up to 46 mm) radiation detector. It was proven that the developed detector shows a fast pulsed response time and a high sensitivity, therefore its rise time is lower than 5 ns, which is two times faster than that of a Si-PIN detector of the same size. And because of the large sensitive area, this detector shows good dominance in fast pulsed and low density radiation detection.

  3. Sensitivity of an underwater acoustic array to ultra-high energy neutrinos

    E-print Network

    Buckingham, Michael

    Sensitivity of an underwater acoustic array to ultra-high energy neutrinos Nikolai G. Lehtinen the possibility of searching for ultra high energy neutrinos in cosmic rays using acoustic techniques in ocean if a shower fully develops in water, would provide a clear neutrino identification. We find that it may

  4. Opioid-mediated pain sensitivity in mice bred for high voluntary wheel running

    E-print Network

    Garland Jr., Theodore

    Opioid-mediated pain sensitivity in mice bred for high voluntary wheel running Guo Lia , Justin S to drugs that block opioid receptors. We first compared tail-flick latency between High-Runner and C female of the opioid antagonist naloxone (10 mg/kg, i.p.) on tail-flick latency during the day (no wheel access). Third

  5. A four-pixel matched collimator for high-sensitivity SPECT imaging

    NASA Astrophysics Data System (ADS)

    Suzuki, Atsuro; Takeuchi, Wataru; Ishitsu, Takafumi; Tsuchiya, Katsutoshi; Ueno, Yuichiro; Kobashi, Keiji

    2013-04-01

    We propose a wide aperture parallel-hole collimator that we call a 4-pixel matched collimator (4-PMC) for high-sensitivity SPECT imaging. The hole size of the 4-PMC is matched to four detector pixels; that is, there are four (2 × 2) pixels per collimator hole. By contrast, a 1-pixel matched collimator (1-PMC) is defined as a collimator whose hole size is matched to one detector pixel. We evaluated four types of collimator (high-resolution collimator versions and high-sensitivity collimator versions of both 4-PMC and 1-PMC) by simulation. SPECT images of a cylindrical phantom with cold spots in the noise-free condition demonstrated that the 4-PMC provided a higher-contrast image than the 1-PMC for the same collimator version. In addition, SPECT images at the noise level corresponding to a human cerebral blood flow study suggested that the high-sensitivity version of the 4-PMC provided the highest contrast image among the four collimator types. In conclusion, the high-sensitivity SPECT system using the 4-PMC can improve the trade-off between spatial resolution and sensitivity and will consequently provide improved image contrast for clinical studies of the human brain compared with the SPECT system using the 1-PMC.

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

    PubMed Central

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

    2014-01-01

    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

  7. Towards high-sensitivity and high-resolution submillimeter-wave video imaging

    NASA Astrophysics Data System (ADS)

    Heinz, Erik; May, Torsten; Born, Detlef; Zieger, Gabriel; Anders, Solveig; Zakosarenko, Viatcheslav; Schubert, Marco; Krause, Torsten; Krüger, André; Schulz, Marco; Meyer, Hans-Georg

    2011-05-01

    Against a background of newly emerged security threats the well-established idea of utilizing submillimeter-wave radiation for personal security screening applications has recently evolved into a promising technology. Possible application scenarios demand sensitive, fast, flexible and high-quality imaging techniques. At present, best results are obtained by passive imaging using cryogenic microbolometers as radiation detectors. Building upon the concept of a passive submillimeter-wave stand-off video camera introduced previously, we present the evolution of this concept in a practical application-ready imaging device. This has been achieved using a variety of measures such as optimizing the detector parameters, improving the scanning mechanism, increasing the sampling speed, and enhancing the camera software. The image generation algorithm has been improved and an automatic sensor calibration technique has been implemented taking advantage of redundancy in the sensor data. The concept is based on a Cassegrain-type mirror optics, an opto-mechanical scanner providing spiraliform scanning traces, and an array of 20 superconducting transition-edge sensors (TES) operated at a temperature of 450-650 mK. The TES are cooled by a closed-cycle cooling system and read out by superconducting quantum interference devices (SQUIDs). The frequency band of operation centers around 350 GHz. The camera can operate at an object distance of 7-10 m. At 9m distance it covers a field of view of 110 cm diameter, achieves a spatial resolution of 2 cm and a pixel NETD (noise equivalent temperature difference) of 0.1-0.4 K. The maximum frame rate is 10 frames per second.

  8. Highly sensitive glucose sensors based on enzyme-modified whole-graphene solution-gated transistors

    PubMed Central

    Zhang, Meng; Liao, Caizhi; Mak, Chun Hin; You, Peng; Mak, Chee Leung; Yan, Feng

    2015-01-01

    Noninvasive glucose detections are convenient techniques for the diagnosis of diabetes mellitus, which require high performance glucose sensors. However, conventional electrochemical glucose sensors are not sensitive enough for these applications. Here, highly sensitive glucose sensors are successfully realized based on whole-graphene solution-gated transistors with the graphene gate electrodes modified with an enzyme glucose oxidase. The sensitivity of the devices is dramatically improved by co-modifying the graphene gates with Pt nanoparticles due to the enhanced electrocatalytic activity of the electrodes. The sensing mechanism is attributed to the reaction of H2O2 generated by the oxidation of glucose near the gate. The optimized glucose sensors show the detection limits down to 0.5??M and good selectivity, which are sensitive enough for non-invasive glucose detections in body fluids. The devices show the transconductances two orders of magnitude higher than that of a conventional silicon field effect transistor, which is the main reason for their high sensitivity. Moreover, the devices can be conveniently fabricated with low cost. Therefore, the whole-graphene solution-gated transistors are a high-performance sensing platform for not only glucose detections but also many other types of biosensors that may find practical applications in the near future. PMID:25655666

  9. Highly sensitive glucose sensors based on enzyme-modified whole-graphene solution-gated transistors

    NASA Astrophysics Data System (ADS)

    Zhang, Meng; Liao, Caizhi; Mak, Chun Hin; You, Peng; Mak, Chee Leung; Yan, Feng

    2015-02-01

    Noninvasive glucose detections are convenient techniques for the diagnosis of diabetes mellitus, which require high performance glucose sensors. However, conventional electrochemical glucose sensors are not sensitive enough for these applications. Here, highly sensitive glucose sensors are successfully realized based on whole-graphene solution-gated transistors with the graphene gate electrodes modified with an enzyme glucose oxidase. The sensitivity of the devices is dramatically improved by co-modifying the graphene gates with Pt nanoparticles due to the enhanced electrocatalytic activity of the electrodes. The sensing mechanism is attributed to the reaction of H2O2 generated by the oxidation of glucose near the gate. The optimized glucose sensors show the detection limits down to 0.5 ?M and good selectivity, which are sensitive enough for non-invasive glucose detections in body fluids. The devices show the transconductances two orders of magnitude higher than that of a conventional silicon field effect transistor, which is the main reason for their high sensitivity. Moreover, the devices can be conveniently fabricated with low cost. Therefore, the whole-graphene solution-gated transistors are a high-performance sensing platform for not only glucose detections but also many other types of biosensors that may find practical applications in the near future.

  10. High degree gravitational sensitivity from Mars orbiters for the GMM-1 gravity model

    NASA Technical Reports Server (NTRS)

    Lerch, F. J.; Smith, D. E.; Chan, J. C.; Patel, G. B.; Chinn, D. S.

    1994-01-01

    Orbital sensitivity of the gravity field for high degree terms (greater than 30) is analyzed on satellites employed in a Goddard Mars Model GMM-1, complete in spherical harmonics through degree and order 50. The model is obtained from S-band Doppler data on Mariner 9 (M9), Viking Orbiter 1 (VO1), and Viking Orbiter 2 (VO2) spacecraft, which were tracked by the NASA Deep Space Network on seven different highly eccentric orbits. The main sensitivity of the high degree terms is obtained from the VO1 and VO2 low orbits (300 km periapsis altitude), where significant spectral sensitivity is seen for all degrees out through degree 50. The velocity perturbations show a dominant effect at periapsis and significant effects out beyond the semi-latus rectum covering over 180 degrees of the orbital groundtrack for the low altitude orbits. Because of the wideband of periapsis motion covering nearly 180 degrees in w and +39 degrees in latitude coverage, the VO1 300 km periapsis altitude orbit with inclination of 39 degrees gave the dominant sensitivity in the GMM-1 solution for the high degree terms. Although the VO2 low periapsis orbit has a smaller band of periapsis mapping coverage, it strongly complements the VO1 orbit sensitivity for the GMM-1 solution with Doppler tracking coverage over a different inclination of 80 degrees.

  11. A highly sensitive CMOS digital Hall sensor for low magnetic field applications.

    PubMed

    Xu, Yue; Pan, Hong-Bin; He, Shu-Zhuan; Li, Li

    2012-01-01

    Integrated CMOS Hall sensors have been widely used to measure magnetic fields. However, they are difficult to work with in a low magnetic field environment due to their low sensitivity and large offset. This paper describes a highly sensitive digital Hall sensor fabricated in 0.18 ?m high voltage CMOS technology for low field applications. The sensor consists of a switched cross-shaped Hall plate and a novel signal conditioner. It effectively eliminates offset and low frequency 1/f noise by applying a dynamic quadrature offset cancellation technique. The measured results show the optimal Hall plate achieves a high current related sensitivity of about 310 V/AT. The whole sensor has a remarkable ability to measure a minimum ± 2 mT magnetic field and output a digital Hall signal in a wide temperature range from -40 °C to 120 °C. PMID:22438758

  12. High Temperature and High Sensitive NOx Gas Sensor with HeteroJunction Structure using Laser Ablation Method

    Microsoft Academic Search

    Wei Gao; Liqin Shi; Yuki Hasegawa; Teruaki Katsube

    2006-01-01

    In order to develop a high temperature (200°C˜400°C) and high sensitive NOx gas sensor, we developed a new structure of SiC-based hetero-junction device Pt\\/SnO2\\/SiC\\/Ni, Pt\\/In2O3\\/SiC\\/Ni and Pt\\/WO3\\/SiC\\/Ni using a laser ablation method for the preparation of both metal (Pt) electrode and metal-oxide film. It was found that Pt\\/In2O3\\/SiC\\/Ni sensor shows higher sensitivity to NO2 gas compared with the Pt\\/SnO2\\/SiC\\/Ni and

  13. High temperature and high sensitive NOx gas sensor with hetero-junction structure using laser ablation method

    Microsoft Academic Search

    Wei Gaol; Liqin Shi; S. A. Khan; Y. Hasegawa; T. Katsube

    2005-01-01

    In order to develop a high temperature (200°C ? 400°C) and high sensitive NOx gas sensor, we developed a new structure of SiC-based hetero-junction device Pt\\/SnO2\\/SiC\\/Ni and Pt\\/WO3\\/SiC\\/Ni using a laser ablation method for the preparation of both metal (Pt) electrode and metal-oxide film. It was found that Pt\\/SnO2\\/SiC\\/Ni sensor show higher sensitivity to NO2 gas compared with the Pt\\/WO3\\/SiC\\/Ni

  14. Human cortical sensitivity to interaural time difference in high-frequency sounds.

    PubMed

    Salminen, Nelli H; Altoè, Alessandro; Takanen, Marko; Santala, Olli; Pulkki, Ville

    2015-05-01

    Human sound source localization relies on various acoustical cues one of the most important being the interaural time difference (ITD). ITD is best detected in the fine structure of low-frequency sounds but it may also contribute to spatial hearing at higher frequencies if extracted from the sound envelope. The human brain mechanisms related to this envelope ITD cue remain unexplored. Here, we tested the sensitivity of the human auditory cortex to envelope ITD in magnetoencephalography (MEG) recordings. We found two types of sensitivity to envelope ITD. First, the amplitude of the auditory cortical N1m response was smaller for zero envelope ITD than for long envelope ITDs corresponding to the sound being in opposite phase in the two ears. Second, the N1m response amplitude showed ITD-specific adaptation for both fine-structure and for envelope ITD. The auditory cortical sensitivity was weaker for envelope ITD in high-frequency sounds than for fine-structure ITD in low-frequency sounds but occurred within a range of ITDs that are encountered in natural conditions. Finally, the participants were briefly tested for their behavioral ability to detect envelope ITD. Interestingly, we found a correlation between the behavioral performance and the neural sensitivity to envelope ITD. In conclusion, our findings show that the human auditory cortex is sensitive to ITD in the envelope of high-frequency sounds and this sensitivity may have behavioral relevance. PMID:25668126

  15. High temperature sensitivity is intrinsic to voltage-gated potassium channels

    PubMed Central

    Yang, Fan; Zheng, Jie

    2014-01-01

    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

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

    NASA Astrophysics Data System (ADS)

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

    2014-01-01

    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.

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

    SciTech Connect

    Zhao, Yujie; Zhao, Wanyu; Chen, Jingkuo; Li, Huayang; Fu, Wuyou, E-mail: hari@hpu.edu.cn, E-mail: fuwy56@163.com; Sun, Guang; Cao, Jianliang; Zhang, Zhanying [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China)] [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China); Bala, Hari, E-mail: hari@hpu.edu.cn, E-mail: fuwy56@163.com [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China) [School of Materials Science and Engineering and Cultivating Base for Key Laboratory of Environment-friendly Inorganic Materials in University of Henan Province, Henan Polytechnic University, Jiaozuo 454000 (China); College of Chemistry and Chemical Engineering, Inner Mongolia University for the Nationalities, Tongliao 028043 (China)

    2014-01-06

    A type of solar cell based on quantum dot (QD) and dye hybrid-sensitized mesoporous TiO{sub 2} film electrode was designed and reported. The electrode was consisted of a TiO{sub 2} nanoparticle (NP) thin film layer sensitized with CdS quantum dot (QD) and an amorphous TiO{sub 2} coated TiO{sub 2} NP thin film layer that sensitized with C106 dye. The amorphous TiO{sub 2} layer was obtained by TiCl{sub 4} 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.

  18. High-sensitivity strain sensor based on in-fiber rectangular air bubble

    NASA Astrophysics Data System (ADS)

    Liu, Shen; Yang, Kaiming; Wang, Yiping; Qu, Junle; Liao, Changrui; He, Jun; Li, Zhengyong; Yin, Guolu; Sun, Bing; Zhou, Jiangtao; Wang, Guanjun; Tang, Jian; Zhao, Jing

    2015-01-01

    We demonstrated a unique rectangular air bubble by means of splicing two sections of standard single mode fibers together and tapering the splicing joint. Such an air bubble can be used to develop a promising high-sensitivity strain sensor based on Fabry-Perot interference. The sensitivity of the strain sensor with a cavity length of about 61 ?m and a wall thickness of about 1 ?m was measured to be up to 43.0 pm/?? and is the highest strain sensitivity among the in-fiber FPI-based strain sensors with air cavities reported so far. Moreover, our strain sensor has a very low temperature sensitivity of about 2.0 pm/°C. Thus, the temperature-induced strain measurement error is less than 0.046 ??/°C.

  19. A Hybrid LPG/CFBG for Highly Sensitive Refractive Index Measurements

    PubMed Central

    Sun, An; Wu, Zhishen

    2012-01-01

    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

  20. Real-time, single-step bioassay using nanoplasmonic resonator with ultra-high sensitivity

    DOEpatents

    Zhang, Xiang; Ellman, Jonathan A; Chen, Fanqing Frank; Su, Kai-Hang; Wei, Qi-Huo; Sun, Cheng

    2014-04-01

    A nanoplasmonic resonator (NPR) comprising a metallic nanodisk with alternating shielding layer(s), having a tagged biomolecule conjugated or tethered to the surface of the nanoplasmonic resonator for highly sensitive measurement of enzymatic activity. NPRs enhance Raman signals in a highly reproducible manner, enabling fast detection of protease and enzyme activity, such as Prostate Specific Antigen (paPSA), in real-time, at picomolar sensitivity levels. Experiments on extracellular fluid (ECF) from paPSA-positive cells demonstrate specific detection in a complex bio-fluid background in real-time single-step detection in very small sample volumes.

  1. Real-Time, Single-Step Bioassay Using Nanoplasmonic Resonator With Ultra-High Sensitivity

    NASA Technical Reports Server (NTRS)

    Zhang, Xiang (Inventor); Ellman, Jonathan A. (Inventor); Chen, Fanqing Frank (Inventor); Su, Kai-Hang (Inventor); Wei, Qi-Huo (Inventor); Sun, Cheng (Inventor)

    2014-01-01

    A nanoplasmonic resonator (NPR) comprising a metallic nanodisk with alternating shielding layer(s), having a tagged biomolecule conjugated or tethered to the surface of the nanoplasmonic resonator for highly sensitive measurement of enzymatic activity. NPRs enhance Raman signals in a highly reproducible manner, enabling fast detection of protease and enzyme activity, such as Prostate Specific Antigen (paPSA), in real-time, at picomolar sensitivity levels. Experiments on extracellular fluid (ECF) from paPSA-positive cells demonstrate specific detection in a complex bio-fluid background in real-time single-step detection in very small sample volumes.

  2. High-sensitivity monitoring of micromechanical vibration using optical whispering gallery mode resonators

    E-print Network

    A. Schliesser; G. Anetsberger; R. Rivière; O. Arcizet; T. J. Kippenberg

    2008-05-12

    The inherent coupling of optical and mechanical modes in high finesse optical microresonators provide a natural, highly sensitive transduction mechanism for micromechanical vibrations. Using homodyne and polarization spectroscopy techniques, we achieve shot-noise limited displacement sensitivities of 10^(-19) m Hz^(-1/2). In an unprecedented manner, this enables the detection and study of a variety of mechanical modes, which are identified as radial breathing, flexural and torsional modes using 3-dimensional finite element modelling. Furthermore, a broadband equivalent displacement noise is measured and found to agree well with models for thermorefractive noise in silica dielectric cavities. Implications for ground-state cooling, displacement sensing and Kerr squeezing are discussed.

  3. Multiplexed highly sensitive detections of cancer biomarkers in thermal space using encapsulated phase change nanoparticles

    NASA Astrophysics Data System (ADS)

    Ma, Liyuan; Hong, Yan; Ma, Zeyu; Kaittanis, Charalambos; Perez, J. Manuel; Su, Ming

    2009-07-01

    We describe a multiplexed highly sensitive method to detect cancer biomarkers using silica encapsulated phase change nanoparticles as thermal barcodes. During phase changes, nanoparticles absorb heat energy without much temperature rise and show sharp melting peaks (0.6 °C). A series of phase change nanoparticles of metals or alloys can be synthesized in such a way that they melt between 100 and 700 °C, thus the multiplicity could reach 1000. The method has high sensitivity (8 nM) that can be enhanced using materials with large latent heat, nanoparticles with large diameter, or reducing the grafting density of biomolecules on nanoparticles.

  4. Highly sensitive colorimetric detection of 17?-estradiol using split DNA aptamers immobilized on unmodified gold nanoparticles

    PubMed Central

    Liu, Jinchuan; Bai, Wenhui; Niu, Shucao; Zhu, Chao; Yang, Shuming; Chen, Ailiang

    2014-01-01

    Gold nanoparticle (AuNP) based colorimetric aptasensor have been developed for many analytes recently largely because of the ease of detection, high sensitivity, and potential for high-throughput analysis. Most of the target aptamers for detection have short sequences. However, the approach shows poor performance in terms of detection sensitivity for most of the long-sequence aptamers. To address this problem, for the first time, we split the 76?mer aptamer of 17?-estradiol into two short pieces to improve the AuNP based colorimetric sensitivity. Our results showed that the split P1 + P2 still retained the original 76?mer aptamer's affinity and specificity but increased the detection limit by 10-fold, demonstrating that as low as 0.1?ng/mL 17?-estradiol could be detected. The increased sensitivity may be caused by lower aptamer adsorption concentration and a lower affinity to the AuNPs of a short single-strand DNA (ssDNA) sequence. Our study provided a new way to use long-sequence aptamers to develop a highly sensitive AuNP-based colorimetric aptasensor. PMID:25524368

  5. A Highly Sensitive Refractometric Sensor Based on Cascaded SiN Microring Resonators

    PubMed Central

    Zamora, Vanessa; Lützow, Peter; Weiland, Martin; Pergande, Daniel

    2013-01-01

    We investigate a highly sensitive optical sensor based on two cascaded microring resonators exploiting the Vernier effect. The architecture consists of two microrings with a slight difference in their free spectral ranges. This allows the generation of the Vernier effect for achieving ultra-high sensitivities. The sensor chip was fabricated using a silicon nitride platform and characterized with isopropanol/ethanol mixtures. A sensitivity of 0.95 nm/% was found for isopropanol concentrations in ethanol ranging from 0% to 10%. Furthermore, a collection of measurements was carried out using aqueous sodium chloride (NaCl) in solutions of different concentrations, confirming a high sensitivity of 10.3 nm/% and a bulk refractive index sensitivity of 6,317 nm/RIU. A limit of detection of 3.16 × 10?6 RIU was determined. These preliminary results show the potential features of cascaded silicon nitride microring resonators for real-time and free-label monitoring of biomolecules for a broad range of applications. PMID:24169543

  6. Ultra high vacuum pumping system and high sensitivity helium leak detector

    DOEpatents

    Myneni, Ganapati Rao (Yorktown, VA)

    1997-01-01

    An improved helium leak detection method and apparatus are disclosed which increase the leak detection sensitivity to 10.sup.-13 atm cc s.sup.-1. The leak detection sensitivity is improved over conventional leak detectors by completely eliminating the use of o-rings, equipping the system with oil-free pumping systems, and by introducing measured flows of nitrogen at the entrances of both the turbo pump and backing pump to keep the system free of helium background. The addition of dry nitrogen flows to the system reduces backstreaming of atmospheric helium through the pumping system as a result of the limited compression ratios of the pumps for helium.

  7. The nature and nurture of high IQ: an extended sensitive period for intellectual development.

    PubMed

    Brant, Angela M; Munakata, Yuko; Boomsma, Dorret I; Defries, John C; Haworth, Claire M A; Keller, Matthew C; Martin, Nicholas G; McGue, Matthew; Petrill, Stephen A; Plomin, Robert; Wadsworth, Sally J; Wright, Margaret J; Hewitt, John K

    2013-08-01

    IQ predicts many measures of life success, as well as trajectories of brain development. Prolonged cortical thickening observed in individuals with high IQ might reflect an extended period of synaptogenesis and high environmental sensitivity or plasticity. We tested this hypothesis by examining the timing of changes in the magnitude of genetic and environmental influences on IQ as a function of IQ score. We found that individuals with high IQ show high environmental influence on IQ into adolescence (resembling younger children), whereas individuals with low IQ show high heritability of IQ in adolescence (resembling adults), a pattern consistent with an extended sensitive period for intellectual development in more-intelligent individuals. The pattern held across a cross-sectional sample of almost 11,000 twin pairs and a longitudinal sample of twins, biological siblings, and adoptive siblings. PMID:23818653

  8. High-Sensitivity Troponin T: A Biomarker for Diuretic Response in Decompensated Heart Failure Patients

    PubMed Central

    Santos, Mário; Almeida, Sofia; Marques, Irene; Bettencourt, Paulo; Carvalho, Henrique

    2014-01-01

    Background. Patients presenting with acutely decompensated heart failure (ADHF) and positive circulating cardiac troponins were found to be a high-risk cohort. The advent of high-sensitive troponins resulted in a detection of positive troponins in a great proportion of heart failure patients. However, the pathophysiological significance of this phenomenon is not completely clear. Objectives. The aim of this study is to determine the early evolution and clinical significance of high-sensitivity troponin T (hsTnT) in ADHF. Methods. Retrospective, secondary analysis of a prospective study including 100 patients with ADHF. Results. Globally, high-sensitivity troponin T decreased from day 1 to day 3 (P = 0,039). However, in the subgroup of patients who remained decompensated no significant differences in hsTnT from day 1 to day 3 were observed (P = 0,955), whereas in successfully compensated patients a significant reduction in hsTnT levels was observed (P = 0,025). High-sensitivity troponin T decrease was correlated with NTproBNP reduction (P = 0,007). Patients with hsTnT increase had longer length of stay (P = 0,033). Conclusions. Episodes of ADHF are associated with transient increases in the blood levels of hsTnT that are reduced with effective acute episode treatment. The decrease in hsTnT can translate less myocardial damage along with favourable ADHF treatment. PMID:25247106

  9. Highly sensitive liquid level monitoring system utilizing polymer fiber Bragg gratings.

    PubMed

    Marques, Carlos A F; Peng, Gang-Ding; Webb, David J

    2015-03-01

    A novel and highly sensitive liquid level sensor based on a polymer optical fiber Bragg grating (POFBG) is experimentally demonstrated. Two different configurations are studied and both configurations show the potential to interrogate liquid level by measuring the strain induced in a POFBG embedded in a silicone rubber diaphragm, which deforms due to hydrostatic pressure variations. The sensor exhibits a highly linear response over the sensing range and a good repeatability. For comparison, a similar sensor using a FBG inscribed in silica fiber is fabricated, which displays a sensitivity that is a factor of 5 smaller than the POFBG. The temperature sensitivity is studied and a novel multi-sensor arrangement proposed which has the potential to provide level readings independent of temperature and the liquid density. PMID:25836830

  10. Highly Sensitive and Fast Anion-Selective InN Quantum Dot Electrochemical Sensors

    NASA Astrophysics Data System (ADS)

    Hassan Alvi, Naveed ul; Rodriguez, Paul E. D. Soto; Gómez, Victor J.; Kumar, Praveen; Willander, Magnus; Nötzel, Richard

    2013-11-01

    Epitaxial InN quantum dots (QDs) are demonstrated as ion-selective electrode for potentiometric anion concentration measurements. The sensor reveals high sensitivity above 90 mV/decade for the detection of chlorine and hydroxyl ions in sodium chloride (NaCl), calcium chloride (CaCl2), and sodium hydroxide (NaOH) solutions. The response time is less than two seconds after which the signal is very stable and repeatable. The sensitivity for the InN QDs is about two times that for a reference InN thin film and the response time is about five times shorter. In pH buffer solutions the sensor reveals no clear response to cations. A model is presented for the high sensitivity, fast response, and ion selectivity based on the unique electronic properties of the InN surface together with the zero-dimensional nature of the QDs.

  11. High IgE sensitization to maize and rice pollen in the highlands of Madagascar

    PubMed Central

    Ramavovololona; Sénéchal, Hélène; Andrianarisoa, Ange; Rakotoarimanana, Vololona; Godfrin, Dominique; Peltre, Gabriel; Poncet, Pascal; Sutra, Jean-Pierre

    2014-01-01

    Introduction Maize and rice are two crops constituting the main food supply in many under-developed and developing countries. Despite the large area devoted to the culture, the sensitization to the pollen from these plants is reported to be low and often considered as an occupational allergy. Methods Sixty five Malagasy pollen allergic patients were clinically and immunochemically investigated with regard to maize and rice pollen allergens. Pollen extracts were electrophoretically separated in 1 and 2 dimensions and IgE and IgG reactivities detected upon immunoblotting. Results When exploring the sensitization profile of Malagasy allergic patients to maize and rice pollen, it appears that a high proportion of these patients consulting during grass pollinating season were sensitized to both pollen as revealed by skin prick testing (62 vs. 59%) and IgE immunoblotting (85 vs. 40%). Several clinically relevant allergens were recognized by patients’ serum IgE in maize and rice pollen extracts. Conclusion The high levels of maize and rice pollen sensitization should be related, in this tropical region, to a specific environmental exposure including i) a proximity of the population to the allergenic sources and ii) a putative exacerbating effect of a highly polluted urban atmosphere on pollen allergenicity. Cross-reactivities between wild and cultivated grasses and also between rice and maize pollen are involved as well as some specific maize sensitizations. The presence of dense urban and peri-urban agriculture, in various African regions and worldwide, could be a high environmental risk factor for people sensitive to maize pollen.

  12. High-frequency stimulation of the hippocampus blocks fear learning sensitization and return of extinguished fear.

    PubMed

    Deschaux, O; Koumar, O-C; Canini, F; Moreau, J-L; Garcia, R

    2015-02-12

    Patients with post-traumatic stress disorder (PTSD) present hippocampal (HPC) dysfunction, which may facilitate fear-related phenomena such as fear learning sensitization (i.e. potentiation of fear acquisition by initial fear conditioning (FC1)) and fear return (i.e. reactivation of extinguished fear). Fear return is sensitive to HPC high-frequency stimulation (HFS) in rats. The goal of the present study was to examine whether fear learning sensitization is also sensitive to HPC HFS in rats. We found in control conditions that, after FC1 (with 15 shock administrations) and extinction, conditioning in a different context with one shock administration was potentiated (proactive effect) and associated with fear return in the initial context (retroactive effect). Both phenomena were prevented by HPC HFS applied before the second conditioning. We also found that the effect of HPC HFS on fear learning sensitization required initial extinction. These findings suggest a pivotal role of the HPC in preventing proactive and retroactive effects of successive fear conditionings. These data also support the concept that HPC deactivation may be involved in fear learning sensitization and fear return in PTSD patients. PMID:25522719

  13. Silicon nano-membrane based photonic crystal microcavities for high sensitivity bio-sensing

    E-print Network

    Chen, Ray

    Silicon nano-membrane based photonic crystal microcavities for high sensitivity bio-sensing Wei for chemical and bio-sensing. Linear L-type microcavities are considered. In contrast to cavities with small mode volumes, but low quality factors for bio-sensing, we showed increasing the length

  14. Transgenic elimination of high-affinity antidepressant and cocaine sensitivity in the presynaptic

    E-print Network

    Blakely, Randy

    Transgenic elimination of high-affinity antidepressant and cocaine sensitivity in the presynaptic. Psychostimulants, such as cocaine and 3,4-methylene- dioxymethamphetamine (i.e., "ecstasy"), also impact 5-HT and cocaine is eliminated. Our animals possess a modified copy of the 5- HT transporter (i.e., SERT, slc6a4

  15. High-sensitivity C-reactive protein levels in players on a major league baseball team

    Microsoft Academic Search

    John D. Cantwell

    2003-01-01

    We performed a high-sensitivity C-reactive protein test in major league baseball players. This test was of limited usefulness on preseason physical examination of 50 major league baseball players. The test is more likely to be of greater value performed on those whose 10-year risk of coronary heart disease is in the 10% to 20% range.

  16. Design performance of a high pressure parallel grids position sensitive gas scintillation proportional counter

    SciTech Connect

    Manzo, G.; Fici, G.M.; Gerardi, G.; Giarrusso, S.; Mistretta, O.; Re, S.

    1985-02-01

    The authors present design performance on an high pressure parallel grids position sensitive Gas Scintillation Proportional Counters (HPGSPC). The detector has a useful geometric area of 450 cm/sup 2/, an energy resolution better than 4% at 60 KeV, a spatial resolution in the millimiters range from 3 to 120 KeV.

  17. Highly sensitive strain detection in strained silicon by surface-enhanced Raman spectroscopy

    Microsoft Academic Search

    Norihiko Hayazawa; Masashi Motohashi; Yuika Saito; Satoshi Kawata

    2005-01-01

    We used surface-enhanced Raman spectroscopy to observe selective amplification of the vibration mode of Si-Si in strained silicon. By covering the silver island film on a strained silicon layer, the Raman signal from the strained silicon can be detected with a high sensitivity compared with the overwhelming background signal from the underlying silicon layer. This technique allowed us to carry

  18. 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. ...

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

    E-print Network

    Chen, Ray

    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

  20. High-sensitivity C-reactive Protein and Tumor Necrosis Factor Alpha in Pseudoexfoliation Syndrome

    PubMed Central

    Sorkhabi, Rana; Ghorbanihaghjo, Amir; Ahoor, Mohamadhossein; Nahaei, Mehriar; Rashtchizadeh, Nadereh

    2013-01-01

    Objectives The purpose of the present study was to determine the alterations in high-sensitivity C-reactive protein and Tumor Necrosis factor alpha levels in the blood serum of pseudoexfoliation syndrome cases (a disease with similar risk factors as systemic endothelial dysfunction diseases) and to compare the results with healthy individuals. Methods High-sensitivity C-reactive protein and Tumor Necrosis factor alpha levels were determined in 30 cases with pseudoexfoliation syndrome and in 30 control patients of the same age and sex, by enzyme-linked immunosorbent assay. Results The levels of high- sensitivity C-reactive protein and Tumor Necrosis factor alpha in the blood serum of patients with pseudoexfoliation syndrome (3.95±0.88 mg/l, 3.32±0.99 pg/ml, respectively) were significantly higher than in the control group (2.51±0.79mg/l, 0.43±0.15 pg/ml, respectively) p=0.001, p=0.002. Conclusion The results suggest that increased levels of high- sensitivity C-reactive protein and Tumor Necrosis factor alpha, as markers of inflammation and peripheral endothelial dysfunction in pseudoexfoliation syndrome, may be risk factors for systemic and ocular manifestations of pseudoexfoliation syndrome. PMID:23386939

  1. High sensitivity Cavity Ring Down spectroscopy O enriched carbon dioxide between 5850 and 7000 cm-1

    E-print Network

    Paris-Sud XI, Université de

    1 High sensitivity Cavity Ring Down spectroscopy of 18 O enriched carbon dioxide between 5850: 15 Number of figures: 10 Key words: Carbon dioxide, CO2, Isotopologue, Global modelling, Cavity Ring More than 19700 transitions belonging to eleven isotopologues of carbon dioxide have been assigned

  2. A Resonant Microaccelerometer With High Sensitivity Operating in an Oscillating Circuit

    Microsoft Academic Search

    Claudia Comi; Alberto Corigliano; Giacomo Langfelder; Antonio Longoni; Alessandro Tocchio; Barbara Simoni

    2010-01-01

    A new micromachined uniaxial silicon resonant accelerometer characterized by a high sensitivity and very small dimensions is presented. The device's working principle is based on the frequency variations of two resonating beams coupled to a proof mass. Under an external acceleration, the movement of the proof mass causes an axial load on the beams, generating opposite stiffness variations, which, in

  3. 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

  4. Modeling and simulation results on high sensitivity scattered gamma-ray emission imaging

    E-print Network

    Nguyen-Verger, Maï K.

    -medical imaging, gamma-ray astronomy, non-destructive industrial testing, environmental survey and control, etcModeling and simulation results on high sensitivity scattered gamma-ray emission imaging C. Driol a simulations Numerical image reconstruction a b s t r a c t A new modality in gamma-ray emission imaging, based

  5. Constructing a High-Sensitivity, Computer-Interfaced, Differential Thermal Analysis Device for Teaching and Research

    ERIC Educational Resources Information Center

    Martinez, L. M.; Videa, M.; Mederos, F.; Mesquita, J.

    2007-01-01

    The construction of a new highly-sensitive, computer-interfaced, differential thermal analysis (DTA) device, used for gathering different information about the chemical reactions, is described. The instrument provides a better understanding about the phase transitions, phase diagrams and many more concepts to the students.

  6. Electrophoretic build-up of multi nanoparticle array for a highly sensitive immunoassay

    E-print Network

    Hammock, Bruce D.

    Electrophoretic build-up of multi nanoparticle array for a highly sensitive immunoassay Jin-Hee Han Accepted 17 August 2012 Available online 6 September 2012 Keywords: Nanoarray Immunoassay Electrophoretic immunoassays to smaller sizes is to immobilize the biological molecules to nanometer-scaled spots. To overcome

  7. Optical fiber sensor based on capillary wall for highly-sensitive refractive index measurement

    NASA Astrophysics Data System (ADS)

    Liu, Yun; Peng, Wei; Zhang, Xinpu; Qian, Siyu

    2014-05-01

    This paper reports a temperature-compensated fiber-optic refractive index (RI) sensor for high sensitivity measurement. The sensor includes a piece of fused-silica capillary (FSC) and a fiber Bragg grating (FBG), both of which are sandwiched by single-mode fibers (SMFs). When light from the lead-in SMF enters into the wall of the FSC that acts as a RI sensing element, multiple modes are excited and interfere to form fringes collected by the lead-out SMF. The FBG is fabricated adjunct to the FSC to compensate its temperature sensitivity. The FSC based sensor prototype is fabricated and sealed in a flow cell to test its performance. Experimental results show that the sensor is highly sensitive to RI, and the sensitivity in the tested RI range from 1.33 to 1.35 is 698.52 nm/RIU and from 1.35 to 1.37 is 1061.78 nm/RIU. The temperature sensitivity of the FSC is -0.173 nm/°C, which is compensated by the FBG. This capillary wall based sensor can be further developed as a miniaturized fiber optic biosensor for biochemical application.

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

    PubMed

    Mende, S B; O'Brien, B J

    1968-08-01

    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

  9. High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range.

    PubMed

    Lin, Tingting; Zhang, Yi; Lee, Yong-Ho; Krause, Hans-Joachim; Lin, Jun; Zhao, Jing

    2014-11-01

    In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-Tc superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz(1/2) are employed as detectors. Considering the flux trapping and operational difficulties associated with low-Tc SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2 fT/Hz(1/2) at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-Tc SQUIDs. PMID:25430134

  10. High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range

    NASA Astrophysics Data System (ADS)

    Lin, Tingting; Zhang, Yi; Lee, Yong-Ho; Krause, Hans-Joachim; Lin, Jun; Zhao, Jing

    2014-11-01

    In several low-field Nuclear Magnetic Resonance (LF-NMR) and surface nuclear magnetic resonance applications, i.e., in the frequency range of kHz, high sensitivity magnetic field detectors are needed. Usually, low-Tc superconducting quantum interference devices (SQUIDs) with a high field sensitivity of about 1 fT/Hz1/2 are employed as detectors. Considering the flux trapping and operational difficulties associated with low-Tc SQUIDs, we designed and fabricated liquid-nitrogen-cooled Cu coils for NMR detection in the kHz range. A cooled coil system consisting of a 9-cm diameter Cu coil and a low noise preamplifier was systematically investigated and reached a sensitivity of 2 fT/Hz1/2 at 77 K, which is 3 times better compared to the sensitivity at 300 K. A Q-switch circuit as an essential element for damping the ringing effects of the pickup coil was developed to acquire free induction decay signals of a water sample with minimum loss of signal. Our studies demonstrate that cooled Cu coils, if designed properly, can provide a comparable sensitivity to low-Tc SQUIDs.

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

    SciTech Connect

    Mu, Haichuan; Zhang, Zhiqiang; Wang, Keke; Xie, Haifen, E-mail: hfxie@ecust.edu.cn [Department of Physics, School of Science, East China University of Science and Technology, 130 Meilong Road, Shanghai 200237 (China); Zhao, Xiaojing; Liu, Feng [Department of Physics, Shanghai Normal University, 100 Guilin Road, Shanghai 200234 (China)

    2014-07-21

    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.

  12. Performance of high-resolution position-sensitive detectors developed for storage-ring decay experiments

    NASA Astrophysics Data System (ADS)

    Yamaguchi, T.; Suzaki, F.; Izumikawa, T.; Miyazawa, S.; Morimoto, K.; Suzuki, T.; Tokanai, F.; Furuki, H.; Ichihashi, N.; Ichikawa, C.; Kitagawa, A.; Kuboki, T.; Momota, S.; Nagae, D.; Nagashima, M.; Nakamura, Y.; Nishikiori, R.; Niwa, T.; Ohtsubo, T.; Ozawa, A.; Sato, K.; Sato, S.; Suzuki, S.

    2013-12-01

    As next generation spectroscopic tools, heavy-ion cooler storage rings will be a unique application of highly charged RI beam experiments. Decay spectroscopy of highly charged rare isotopes provides us important information relevant to the stellar conditions, such as for the s- and r-process nucleosynthesis. In-ring decay products of highly charged RI will be momentum-analyzed and reach a position-sensitive detector set-up located outside of the storage orbit. To realize such in-ring decay experiments, we have developed and tested two types of high-resolution position-sensitive detectors: silicon strips and scintillating fibers. The beam test experiments resulted in excellent position resolutions for both detectors, which will be available for future storage-ring experiments.

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

    Microsoft Academic Search

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

    2007-01-01

    Real time monitoring of biowarfare agents (BWA) for military and civilian protection remains a high priority for homeland security and battlefield readiness. Available devices have adequate sensitivity, but the detection modules have limited periods of deployment, require frequent maintenance, employ single-use disposable components, and have limited multiplexing capability. Surface Plasmon Resonance enhanced Common Path Interferometry (SPR-CPI) is a label-free, high

  14. A High-Resolution Accelerometer With Electrostatic Damping and Improved Supply Sensitivity

    Microsoft Academic Search

    Mikail Yucetas; Mika Pulkkinen; Antti Kalanti; Jarno Salomaa; Lasse Aaltonen; Kari Halonen

    2012-01-01

    In this paper, a charge-balancing accelerometer is presented. A hybrid interface topology is utilised to achieve high resolution, high linearity and low power supply sensitivity. The accelerometer consists of a micromechanical sensor element, a self-balancing bridge (SBB) open-loop readout, AC force feedback and $\\\\Delta \\\\Sigma$ ADC. The SBB converts acceleration to ratiometric voltage. The ratiometric output of the SBB is

  15. High-speed and sensitive multiple-point ammonia gas monitor system

    Microsoft Academic Search

    Y. Matsuyoshi; Yuuichi Satoh; Tsutomu Shinozaki; Eiko Suzuki; Norimasa Nagata

    1999-01-01

    In order to get a precise pattern control in a chemically amplified photo-resist process, the high performance multi-point ammonia gas monitor was developed. A single point high speed and sensitive ammonia monitor was reported in ISSM'96. This system has expanded its ability by adding 16 measurement ports, 4 diffusion scrubbers, and one analyzer. As a result, it provided the capability

  16. Sensitization of High-Nitrogen Austenitic Stainless Steels by Dichromium Nitride Precipitation

    Microsoft Academic Search

    J. W. Simmons; J. C. Rawers; D. G. Atteridge

    1994-01-01

    High-nitrogen (N) stainless steels (SS) are receiving increased attention because of their strength advantages over carbon (C)-alloyed materials, but they have been found susceptible to dichromium nitride (Cr[sub 2]N) precipitation during thermal exposure between [approximately]600 C and 1,050 C. Sensitization susceptibility of a high-N, low-C austenitic SS by Cr[sub 2]N precipitation at 700 C and 900 C was determined using

  17. A high-sensitivity search for extraterrestrial intelligence at lambda 18 CM

    Microsoft Academic Search

    J. Tarter; J. Cuzzi; D. Black; T. Clark

    1980-01-01

    A targeted high-sensitivity search for narrow-band signals near a wavelength of 18 cm has been conducted using the 91-m radiotelescope of the National Radio Astronomy Observatory. The search included 201 nearby solar-type stars and achieved a frequency resolution of 5.5 Hz over a 1.4-MHz bandwidth. This high spectral resolution was obtained through a non-real-time reduction procedure using a Mark I

  18. Development of pressure sensitive molecular film applicable to pressure measurement for high Knudsen number flows

    NASA Astrophysics Data System (ADS)

    Matsuda, Yu; Mori, Hideo; Niimi, Tomohide; Uenishi, Hiroyuki; Hirako, Madoka

    2007-04-01

    Experimental analyses of thermo-fluid phenomena of micro- and nano-flows with high Knudsen number need the measurement techniques based on interaction of atoms or molecules with photons. The pressure-sensitive paint (PSP) technique has potential as a diagnostic tool for pressure measurement in the high Knudsen number regime because it works as a so-called “molecular sensor”. However, application of PSP to micro devices is very difficult because the conventional PSP is too thick owing to the use of polymer binder and does not have sufficient spatial resolution for pressure measurement of micro-flows. In this study, we have adopted the Langmuir-Blodgett (LB) technique to fabricate pressure sensitive molecular films (PSMFs) using Pd(II) Octaethylporphine (PdOEP) and Pd(II) Mesoporphyrin IX (PdMP) to resolve ordinary PSPs problems, and have tested these PSMFs to evaluate the feasibility of the pressure measurement around micro-devices. It is clarified that the PSMF composed of PdMP has higher sensitivity than that of PdOEP. Since it is also considered that the sensitivity of PSMFs can be increased by introducing arachidic acid (AA) as spacer molecules of LB films to prevent the aggregation of luminescent molecules, we have produced PSMFs with several molar ratio of PdMP to AA. At the most suitable ratio, the PSMF has high sensitivity in the low pressure region with high Knudsen number, even if the amount of the luminescent molecules in the PSMF layer is smaller than that in conventional PSPs. This result indicates that the PSMF is feasible to measure the pressure in high Knudsen number flows such as micro-flows.

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

    NASA Astrophysics Data System (ADS)

    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

    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 mission—derived from the Imaging X-ray Polarimetry Explorer (IXPE) proposed to a previous NASA call—takes 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).

  20. Thermal sensitivity studies of fibre Bragg gratings inscribed by high-intensity femtosecond UV laser pulses

    Microsoft Academic Search

    Jean-François Rysman; David N. Nikogosyan

    2009-01-01

    We studied the thermal sensitivity of fibre Bragg gratings (FBGs), fabricated in single-mode standard telecom (SMF-28) and photosensitive Ge\\/B codoped (Fibercore PS 1250\\/1500) fibres with high-intensity (140–210 GW\\/cm2) 264nm 220 fs laser pulses. The accurate measurement of Bragg wavelength thermal shift in the mentioned fibres brought about the values of 9.62±0.04 and 8.03±0.12pm\\/°C, respectively. The comparison of the thermal sensitivity

  1. Polarimetric fiber grating biosensor for in-situ high-sensitive intracellular density measurement

    NASA Astrophysics Data System (ADS)

    Guo, Tuan; Liu, Fu; Liu, Yu; Chen, Nan-Kuang; Guan, Bai-Ou; Albert, Jacques

    2014-05-01

    High sensitivity biological sample measurements have been achieved by using a 12o tilted fiber Bragg grating (TFBG). Human acute leukemia cells with different intracellular densities and refractive index (RI) ranging from 1.3342 to 1.3344 were clearly discriminated in-situ by using the differential transmission spectrum between two orthogonal polarizations for the last guided mode resonance before "cut-off", with an amplitude variation sensitivity of 1.8×104 dB/RIU and a limit of detection of 2×10-5 RIU. The technique is inherently temperature-insensitive.

  2. Compact highly sensitive multi-species airborne mid-IR spectrometer

    NASA Astrophysics Data System (ADS)

    Richter, Dirk; Weibring, Petter; Walega, James G.; Fried, Alan; Spuler, Scott M.; Taubman, Matthew S.

    2015-02-01

    We report on the development and airborne field deployment of a mid-IR laser-based spectrometer. The instrument was configured for the simultaneous in situ detection of formaldehyde (CH2O) and ethane (C2H6). Numerous mechanical, optical, electronic, and software improvements over a previous instrument design resulted in reliable highly sensitive airborne operation with long stability times yielding 90 % airborne measurement coverage during the recent air quality study over the Colorado Front Range, FRAPPÉ 2014. Airborne detection sensitivities of ~15 pptv (C2H6) and ~40 pptv (CH2O) were generally obtained for 1 s of averaging for simultaneous detection.

  3. High sensitivity chlorine gas sensors using multicomponent transparent conducting oxide thin films

    Microsoft Academic Search

    Toshihiro Miyata; Tomohiro Hikosaka; Tadatsugu Minami

    2000-01-01

    Newly developed semiconductor thin-film gas sensors with a high sensitivity for chlorine (Cl2) gas using multicomponent transparent conducting oxide (TCO) thin films such as MgO–In2O3, ZnO–In2O3 and Zn2In2O5–MgIn2O4 are described. The multicomponent oxide thin-film gas sensors used in this work exhibited an increase in resistance with exposure to Cl2 gas. The sensitivity of multicomponent TCO thin-film gas sensors could be

  4. High sensitive detection of field-induced susceptibility modulation with circuit resonance

    NASA Astrophysics Data System (ADS)

    Zhang, M.; Shimizu, K.; Nozaki, Y.; Matsuyama, K.

    2007-03-01

    A high sensitive detection of reversible susceptibility in magnetic thin films was performed with an electric circuit resonant technique. A multilayer sample of [NiFe(100 nm)/Cu(10 nm)] 5 exihibits the most sensitive modulation effect among the fabricated samples. That is, the resonance frequency fr, was decreased with the bias field Hb from 9.3 ( Hb=0 Oe) to 8.6 MHz ( Hb=6.0 Oe) at an exciting field Hex=70 mOe. The marked fr change can be associated with the field-induced susceptibility modulation in the soft magnetic thin film.

  5. A gyroscope fabrication method for high sensitivity and robustness to fabrication tolerances

    NASA Astrophysics Data System (ADS)

    Sung, Jungwoo; Kim, Jin Young; Seok, Seyeong; Kwon, Hyuckjin J.; Kim, Minseo; Kim, Geonhwee; Lim, Geunbae

    2014-07-01

    MEMS gyroscopes have favorable characteristics, including small size, high throughput, and low cost. The performance of MEMS gyroscopes depends on the displacement sensitivity of the capacitors. In this paper, we describe the fabrication of 300-µm-thick gyroscopes that can provide high displacement sensitivity and are robust to fabrication tolerances, i.e. deep reactive ion etch (DRIE) rate uniformity. When thick structures are perforated using DRIE to achieve high-aspect-ratio features, footing is commonly observed. However, we describe a fabrication method that circumvents problems associated with footing and side-wall etching, so that the gyroscopes can have uniform dimensions and small variations across the wafer. Using a post-fabrication translation approach, the position of capacitors is modified following DRIE, and the gap in the gyroscopes can be reduced to 3??m, which leads to an aspect ratio of 100. Using this method, we fabricated MEMS gyroscopes that can overcome the DRIE aspect ratio limit and have capacitors with higher sensitivities than those of other gyroscopes, which typically employ substrates that are less than 100?µm thick. The gyroscope had a resonant frequency of 9.91?kHz, a quality factor of 2500 and a sensitivity of 23?mV/[deg/s].

  6. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    NASA Astrophysics Data System (ADS)

    Andersen, T.; Jensen, R.; Christensen, M. K.; Pedersen, T.; Hansen, O.; Chorkendorff, I.

    2012-07-01

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/?m > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH3.

  7. High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors

    SciTech Connect

    Andersen, T.; Jensen, R.; Christensen, M. K.; Chorkendorff, I. [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); Pedersen, T.; Hansen, O. [Department of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech Building 345 East, DK-2800 Kgs. Lyngby (Denmark)

    2012-07-15

    We demonstrate a combined microreactor and time of flight system for testing and characterization of heterogeneous catalysts with high resolution mass spectrometry and high sensitivity. Catalyst testing is performed in silicon-based microreactors which have high sensitivity and fast thermal response. Gas analysis is performed with a time of flight mass spectrometer with a modified nude Bayard-Alpert ionization gauge as gas ionization source. The mass resolution of the time of flight mass spectrometer using the ion gauge as ionization source is estimated to m/{Delta}m > 2500. The system design is superior to conventional batch and flow reactors with accompanying product detection by quadrupole mass spectrometry or gas chromatography not only due to the high sensitivity, fast temperature response, high mass resolution, and fast acquisition time of mass spectra but it also allows wide mass range (0-5000 amu in the current configuration). As a demonstration of the system performance we present data from ammonia oxidation on a Pt thin film showing resolved spectra of OH and NH{sub 3}.

  8. Ultrasensitive UPLC-MS-MS method for the quantitation of etheno-DNA adducts in human urine.

    PubMed

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

    2014-01-01

    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/µmol 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

  9. An UPLC-MS-based metabolomics investigation on the anti-fatigue effect of salidroside in mice.

    PubMed

    Ma, Chaoyang; Hu, Liming; Tao, Guanjun; Lv, Wenping; Wang, Hongxin

    2015-02-01

    An ultra-performance liquid chromatography-quadrupole time-of-flight-based metabolomic approach was developed to study influence of salidroside, an anti-fatigue ingredient from Rhoiola rosea, on urinary metabolic profiling of rats to a single dose of 180 mg/kg per day. Unsupervised principal component analysis (PCA) and supervised orthogonal pre-projection to latent structures discriminate analysis (OPLS-DA) on metabolite profiling revealed obvious differentiation between the salidroside treated groups and controls in both positive and negative ion modes. Eleven urinary metabolites contributing to the differentiation were identified as anti-fatigue biomarkers: N-acetylserotonin, 2-Methoxyestrone 3-glucuronide, Taurine, Melatonin, Sorbitol, Geranyl diphosphate, Z-nucleotide, Cortisone, Dihydrocortisol, Sebacic acid, Pregnenolone sulfate. The physiological significance of these biomarkers is discussed. The work showed that metabolomics is a powerful tool in studying the anti-fatigue effects of natural compound salidroside on multiple targets in vivo. PMID:25543286

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

    PubMed Central

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

    2014-01-01

    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/µmol 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

  11. An optimized method for measuring methylmalonic acid in low volumes of serum using UPLC-MS/MS

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Background: Methylmalonic acid (MMA) is a metabolic intermediate which is transformed to succinic acid (SA) by a vitamin B12-dependent catalytic step. MMA is broadly used as a clinical biomarker of functional vitamin B12 status. However, currently validated protocols use between 100 -1000 µL of se...

  12. Determination of Zilpaterol in Horse Urine from Withdrawal Day 0 to Day 21 by UPLC-MS/MS and ELISA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Zilpaterol is a beta-adrenergic agonist that is approved in the United States, Mexico and South Africa as a feed additive to increase weight gain and improve feed efficiency of cattle. Beta-adrenergic agonists have a long history of illicit and off-label use in livestock, competitive sport animals,...

  13. UPLC-MS-based analysis of human plasma for metabonomics using solvent precipitation or solid phase extraction.

    PubMed

    Michopoulos, Filippos; Lai, Lindsay; Gika, Helen; Theodoridis, Georgios; Wilson, Ian

    2009-04-01

    A study of the factors involved in obtaining valid global metabolite profiles from the LC-MS of human plasma for the purposes of metabonomic analysis has been undertaken. Plasma proteins were either precipitated with 3 vol of organic solvent (methanol or acetonitrile) or subjected to solid phase extraction (SPE) on a C18-bonded phase. For chromatography, a reversed-phase gradient system, based on acidified water/methanol, was used. Ultra performance liquid chromatography (UPLC) was performed on a C18-bonded stationary phase using sub 2 microm particles packed into a 2.1 x 100 mm column. The eluent from the column was subjected to analysis by positive electrospray ionization using a time-of-flight mass spectrometer. To obtain reproducible results for solvent-precipitated plasma, the "conditioning" of the system with injections of matrix prior to the main analytical run was essential. The repeatability of the methodology was improved significantly when the sample preparation was performed using solid phase extraction. PMID:19714883

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

    PubMed Central

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

    2011-01-01

    Background Because 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 Findings FCS has the advantage of allowing us to determine the number of fluorescent molecules. FCS measures the fluctuations in fluorescence intensity caused by fluorescent probe movement in a small light cavity with a defined volume generated by confocal illumination. We thus developed a highly sensitive determination system of H2O2 by FCS, where horseradish peroxidase (HRP) catalyzes the formation of a covalent bond between fluorescent molecules and proteins in the presence of H2O2. Our developed system gave a linear calibration curve for H2O2 in the range of 28 to 300 nM with the detection limit of 8 nM. In addition, by coupling with glucose oxidase (GOD)-catalyzed reaction, the method allows to measure glucose in the range of 80 nM to 1.5 µM with detection limit of 24 nM. The method was applicable to the assay of glucose in blood plasma. The mean concentration of glucose in normal human blood plasma was determined to be 4.9 mM. Conclusions/Significance In comparison with commercial available methods, the detection limit and the minimum value of determination for glucose are at least 2 orders of magnitude more sensitive in our system. Such a highly sensitive method leads the fact that only a very small amount of plasma (20 nL) is needed for the determination of glucose concentration in blood plasma. PMID:21850246

  15. A position sensitive high resolution hodoscope for particle unstable intermediate mass fragments

    NASA Astrophysics Data System (ADS)

    Murakami, T.; Nayak, T. K.; Lynch, W. G.; Swartz, K.; Chen, Z.; Fields, D. J.; Gelbke, C. K.; Kim, Y. D.; Maier, M. R.; Pochodzalla, J.; Tsang, M. B.; Xu, H. M.; Zhu, F.

    1989-02-01

    A position sensitive high resolution hodoscope was developed to detect particle unstable intermediate mass fragments and to resolve the individual excited states of these nuclei. The hodoscope consists of 13 telescopes, four of these telescopes were designed to isotopically resolve fragments with 3 <= Z <= 10 and the other nine to resolve hydrogen and helium isotopes. In order to optimize the excitation energy resolution of the hodoscope, each telescope contains an x - y position sensitive gas proportional counter. A position resolution better than 0.5 mm is obtained for 5.8 MeV ?-particles. This position sensitivity also allows compensation for the thickness nonuniformity of the nonplanar silicon detectors incorporated in the nine light particle telescopes. For proton decay channels of the particle unstable nucleus 14N* produced in 14N induced reactions on natAg at E/A = 35 MeV, the hodoscope provides an excitati energy resolution of about 60 keV (FWHM).

  16. A sensitive, high resolution magic angle turning experiment for measuring chemical shift tensor principal values

    NASA Astrophysics Data System (ADS)

    Alderman, D. W.

    1998-12-01

    A sensitive, high-resolution 'FIREMAT' two-dimensional (2D) magic-angle-turning experiment is described that measures chemical shift tensor principal values in powdered solids. The spectra display spinning-sideband patterns separated by their isotropic shifts. The new method's sensitivity and high resolution in the isotropic-shift dimension result from combining the 5pi magic-angle-turning pulse sequence, an extension of the pseudo-2D sideband-suppression data rearrangement, and the TIGER protocol for processing 2D data. TPPM decoupling is used to enhance resolution. The method requires precise synchronization of the pulses and sampling to the rotor position. It is shown that the technique obtains 35 natural-abundance 13C tensors from erythromycin in 19 hours, and high quality naturalabundance 15N tensors from eight sites in potassium penicillin V in three days on a 400MHz spectrometer.

  17. Ultra-sensitive high-density Rb-87 radio-frequency magnetometer

    SciTech Connect

    Savukov, I.; Boshier, M. G. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Karaulanov, T. [CNLS - Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    2014-01-13

    Radio-frequency (RF) atomic magnetometers (AMs) can be used in many applications, such as magnetic resonance imaging and nuclear quadrupole resonance. High-density AMs provide both superior sensitivity and large bandwidth. Previously, high-density potassium AMs were demonstrated, but these magnetometers have various disadvantages, such as high-temperature of operation and bulky design. We demonstrate a rubidium-87 RF AM with 5 fT/Hz{sup 1/2} sensitivity (3 fT Hz{sup 1/2} probe noise), which is comparable to that of the best potassium magnetometers. Our magnetometer also features a simple fiber-optic design, providing maximum flexibility for magnetic-field measurements.

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

    SciTech Connect

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

    2013-12-30

    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.

  19. Using confined self-adjusting carbon nanotube arrays as high-sensitivity displacement sensing element.

    PubMed

    Lee, Jae-Ik; Eun, Youngkee; Choi, Jungwook; Kwon, Dae-Sung; Kim, Jongbaeg

    2014-07-01

    Displacement sensing is a fundamental process in mechanical sensors such as force sensors, pressure sensors, accelerometers, and gyroscopes. Advanced techniques utilizing nanomaterials have attracted considerable attention in the drive to enhance the process. In this paper, we propose a novel and highly sensitive device for detecting small displacements. The device utilizes the changes in contact resistance between two sets of vertically aligned carbon nanotube (CNT) arrays, the growth of which was confined to enable their facile and reliable integration with fully fabricated microstructures. Using the displacement transduction of the proposed device, we successfully demonstrated a 3-axis wide bandwidth accelerometer, which was experimentally confirmed to be highly sensitive compared to conventional piezoresistive sensors. Through a test involving 1.2 million cycles of displacement transductions, the contact resistance of the CNT arrays was proved to be excellently stable, which was a consequence of the high electrical stability and mechanical durability of the CNTs. PMID:24914449

  20. Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes

    NASA Astrophysics Data System (ADS)

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

    2013-06-01

    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.

  1. Large area CMOS bio-pixel array for compact high sensitive multiplex biosensing.

    PubMed

    Sandeau, Laure; Vuillaume, Cassandre; Contié, Sylvain; Grinenval, Eva; Belloni, Federico; Rigneault, Hervé; Owens, Roisin M; Fournet, Margaret Brennan

    2015-02-01

    A novel CMOS bio-pixel array which integrates assay substrate and assay readout is demonstrated for multiplex and multireplicate detection of a triplicate of cytokines with single digit pg ml(-1) sensitivities. Uniquely designed large area bio-pixels enable individual assays to be dedicated to and addressed by single pixels. A capability to simultaneously measure a large number of targets is provided by the 128 available pixels. Chemiluminescent assays are carried out directly on the pixel surface which also detects the emitted chemiluminescent photons, facilitating a highly compact sensor and reader format. The high sensitivity of the bio-pixel array is enabled by the high refractive index of silicon based pixels. This in turn generates a strong supercritical angle luminescence response significantly increasing the efficiency of the photon collection over conventional farfield modalities. PMID:25490928

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

    SciTech Connect

    Shen, Yufeng; Smith, Richard D.

    2005-06-01

    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), including high sensitivity and high resolution Fourier transform ion cyclotron resonance (FTICR) MS. This technology enables MS analysis of low nanogram-level proteomic samples (i.e., nanoscale proteomics) with individual protein identification sensitivity at the low zeptomole-level. The resultant protein measurement dynamic range can reach 106 for nanogram-sized proteomic samples, while more abundant proteins can be detected from complex sub-picogram size proteome samples. The average proteome identification throughput using MS/MS is >200 proteins/h for a ~3 h analysis. These qualities provide the foundation for proteomics studies of single or small populations of cells. The instrumental robustness required for automation and providing high quality routine performance nanoscale proteomic analyses is also discussed.

  3. High Sensitivity Combined with Extended Structural Coverage of Labile Compounds via Nanoelectrospray Ionization at Subambient Pressures

    SciTech Connect

    Cox, Jonathan T.; Kronewitter, Scott R.; Shukla, Anil K.; Moore, Ronald J.; Smith, Richard D.; Tang, Keqi

    2014-10-07

    Subambient pressure ionization with nanoelectrospray (SPIN) has proven to be effective in producing ions with high efficiency and transmitting them to low pressures for high sensitivity mass spectrometry (MS) analysis. Here we present evidence that not only does the SPIN source improve MS sensitivity but also allows for gentler ionization conditions. The gentleness of a conventional heated capillary electrospray ionization (ESI) source and the SPIN source was compared by the liquid chromatography mass spectrometry (LC-MS) analysis of colominic acid. Colominic acid is a mixture of sialic acid polymers of different lengths containing labile glycosidic linkages between monomer units necessitating a gentle ion source. By coupling the SPIN source with high resolution mass spectrometry and using advanced data processing tools, we demonstrate much extended coverage of sialic acid polymer chains as compared to using the conventional ESI source. Additionally we show that SPIN-LC-MS is effective in elucidating polymer features with high efficiency and high sensitivity previously unattainable by the conventional ESI-LC-MS methods. ?

  4. The Sensitivity of HAWC to High-Mass Dark Matter Annihilations

    E-print Network

    A. U. Abeysekara; R. Alfaro; C. Alvarez; J. D. Alvarez; R. Arceo; J. C. Arteaga-Velazquez; 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. Carraminana; M. Castillo; U. Cotti; J. Cotzomi; E. de la Fuente; C. De Leon; T. DeYoung; R. Diaz Hernandez; L. Diaz-Cruz; J. C. Diaz-Velez; B. L. Dingus; M. A. DuVernois; R. W. Ellsworth; S. F. E.; D. W. Fiorino; N. Fraija; A. Galindo; F. Garfias; M. M. Gonzalez; J. A. Goodman; V. Grabski; M. Gussert; Z. Hampel-Arias; J. P. Harding; C. M. Hui; P. Huentemeyer; A. Imran; A. Iriarte; P. Karn; D. Kieda; G. J. Kunde; A. Lara; R. J. Lauer; W. H. Lee; D. Lennarz; H. Leon Vargas; E. C. Linares; J. T. Linnemann; M. Longo; R. Luna-Garcia; A. Marinelli; H. Martinez; O. Martinez; J. Martinez-Castro; J. A. J. Matthews; J. McEnery; E. Mendoza Torres; P. Miranda-Romagnoli; E. Moreno; M. Mostafa; L. Nellen; M. Newbold; R. Noriega-Papaqui; T. Oceguera-Becerra; B. Patricelli; R. Pelayo; E. G. Perez-Perez; J. Pretz; C. Riviere; D. Rosa-Gonzalez; 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. Villasenor; T. Weisgarber; S. Westerhoff; I. G. Wisher; J. Wood; G. B. Yodh; P. W. Younk; D. Zaborov; A. Zepeda; H. Zhou; K. N. Abazajian

    2014-12-09

    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 Spring 2015. In this paper, we study the HAWC sensitivity to the gamma-ray signatures of high-mass (multi- TeV) dark matter annihilation. The HAWC observatory will be sensitive to diverse searches for dark matter annihilation, including annihilation from extended dark matter sources, the diffuse gamma-ray emission from dark matter annihilation, and gamma-ray emission from 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 in the mass range where HAWC has similar sensitivity. HAWC can additionally explore higher dark matter masses than are currently constrained.

  5. Molecular basis for the high THIP/gaboxadol sensitivity of extrasynaptic GABA(A) receptors.

    PubMed

    Meera, Pratap; Wallner, Martin; Otis, Thomas S

    2011-10-01

    Extrasynaptic GABA(A) receptors (eGABARs) allow ambient GABA to tonically regulate neuronal excitability and are implicated as targets for ethanol and anesthetics. These receptors are thought to be heteropentameric proteins made up of two ? subunits-either ?4 or ?6-two ?2 or ?3 subunits, and one ? subunit. The GABA analog 4,5,6,7-tetrahydroisoxazolo (5,4-c)pyridin-3(-ol) (THIP) has been proposed as a selective ligand for eGABARs. Behavioral and in vitro studies suggest that eGABARs have nanomolar affinity for THIP; however, all published studies on recombinant versions of eGABARs report micromolar affinities. Here, we examine THIP sensitivity of native eGABARs on cerebellar neurons and on reconstituted GABARs in heterologous systems. Concentration-response data for THIP, obtained from cerebellar granule cells and molecular layer interneurons in wild-type and ? subunit knockout slices, confirm that submicromolar THIP sensitivity requires ? subunits. In recombinant experiments, we find that ? subunit coexpression leads to receptors activated by nanomolar THIP concentrations (EC(50) of 30-50 nM for ?4?3? and ?6?3?), a sensitivity almost 1,000-fold higher than receptors formed by ?4/6 and ?3 subunits. In contrast, ?2 subunit expression significantly reduces THIP sensitivity. Even when ? subunit cDNA or cRNA was supplied in excess, high- and low-sensitivity THIP responses were often apparent, indicative of variable mixtures of low-affinity ?? and high-affinity ??? receptors. We conclude that ? subunit incorporation into GABARs leads to a dramatic increase in THIP sensitivity, a defining feature that accounts for the unique behavioral and neurophysiological properties of THIP. PMID:21795619

  6. Spatial sensitivities of human health risk to intercontinental and high-altitude pollution

    NASA Astrophysics Data System (ADS)

    Koo, Jamin; Wang, Qiqi; Henze, Daven K.; Waitz, Ian A.; Barrett, Steven R. H.

    2013-06-01

    We perform the first long-term (>1 year) continuous adjoint simulations with a global atmospheric chemistry-transport model focusing on population exposure to fine particulate matter (PM2.5) and associated risk of early death. Sensitivities relevant to intercontinental and high-altitude PM pollution are calculated with particular application to aircraft emissions. Specifically, the sensitivities of premature mortality risk in different regions to NOx, SOx, CO, VOC and primary PM2.5 emissions as a function of location are computed. We apply the resultant sensitivity matrices to aircraft emissions, finding that NOx emissions are responsible for 93% of population exposure to aircraft-attributable PM2.5. Aircraft NOx accounts for all of aircraft-attributable nitrate exposure (as expected) and 53% of aircraft-attributable sulfate exposure due to the strong "oxidative coupling" between aircraft NOx emissions and non-aviation SO2 emissions in terms of sulfate formation. Of the health risk-weighted human PM2.5 exposure attributable to aviation, 73% occurs in Asia, followed by 18% in Europe. 95% of the air quality impacts of aircraft emissions in the US are incurred outside the US. We also assess the impact of uncertainty or changes in (non-aviation) ammonia emissions on aviation-attributable PM2.5 exposure by calculating second-order sensitivities. We note the potential application of the sensitivity matrices as a rapid policy analysis tool in aviation environmental policy contexts.

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

    NASA Technical Reports Server (NTRS)

    Paduano, James D.; Downing, David R.

    1987-01-01

    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.

  8. High-sensitivity sapphire cells for high pressure NMR spectroscopy on proteins

    Microsoft Academic Search

    Martin Reinhard Arnold; Hans Robert Kalbitzer; Werner Kremer

    2003-01-01

    High pressure NMR spectroscopy is a most exciting method for studying the structural anisotropy and conformational dynamics of proteins. The restricted volume of the high pressure glass cells causes a poor signal to noise ratio which up to now renders the application of most of the multidimensional NMR experiments impossible. The method presented here using high strength single crystal sapphire

  9. A high-sensitivity thromboplastin reagent prepared from cultured human cells.

    PubMed

    Valdes-Camin, R; Callahan, J B; Ebert, R F

    1994-08-01

    High-sensitivity thromboplastin reagents suitable for use in the prothrombin time (PT) assay are typically prepared from human brain and placenta, tissues that are in limited supply and subject to viral contamination. Cloning and expression of recombinant human tissue factor (TF) has enabled production of a new generation of thromboplastin reagents whose performance and utility are under active investigation. The purpose of this study was to determine the feasibility of producing a sensitive human thromboplastin reagent from a non-recombinant source: cultured human cells. Several human cell lines with apparently high constitutive TF synthesis were identified, and a viable thromboplastin reagent (Humaplastin) was produced from a human lung cell line via a non-conventional process that did not require reconstitution or rehydration of TF in cell membranes. When calibrated against BCT/253, a human brain international reference thromboplastin, Humaplastin exhibited a mean normal prothrombin time of 12.6 +/- 0.7 s (mean +/- SD: n = 20) and an International Sensitivity Index of 1.09 +/- 0.019. The performance of this reagent was well correlated (r = 0.983) with Thromborel S, a commercially available human placental thromboplastin reagent. Orthogonal least squares regression of the log PT values from the placental thromboplastin reagent versus Humaplastin and two recombinant TF-based thromboplastin reagents suggested that the latter three reagents are somewhat more sensitive than the placental thromboplastin reagent, although such differences should not be expected to have a significant impact on clinical utility. It is concluded that cultured human lung cells represent a suitable source of tissue thromboplastin for production of a high-sensitivity non-recombinant thromboplastin reagent. PMID:7841320

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

    NASA Astrophysics Data System (ADS)

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

    2014-09-01

    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 µs temporal resolution.

  11. High Sensitivity Gas Detection Using a Macroscopic Three-Dimensional Graphene Foam Network

    PubMed Central

    Yavari, Fazel; Chen, Zongping; Thomas, Abhay V.; Ren, Wencai; Cheng, Hui-Ming; Koratkar, Nikhil

    2011-01-01

    Nanostructures are known to be exquisitely sensitive to the chemical environment and offer ultra-high sensitivity for gas-sensing. However, the fabrication and operation of devices that use individual nanostructures for sensing is complex, expensive and suffers from poor reliability due to contamination and large variability from sample-to-sample. By contrast, conventional solid-state and conducting-polymer sensors offer excellent reliability but suffer from reduced sensitivity at room-temperature. Here we report a macro graphene foam-like three-dimensional network which combines the best of both worlds. The walls of the foam are comprised of few-layer graphene sheets resulting in high sensitivity; we demonstrate parts-per-million level detection of NH3 and NO2 in air at room-temperature. Further, the foam is a mechanically robust and flexible macro-scale network that is easy to contact (without Lithography) and can rival the durability and affordability of traditional sensors. Moreover, Joule-heating expels chemisorbed molecules from the foam's surface leading to fully-reversible and low-power operation. PMID:22355681

  12. Development of a high sensitivity, nested Q-PCR assay for mouse and human aromatase.

    PubMed

    Liu, Gui-Jian; Liu, Giujian; Wu, Yu-Sheen; Brenin, David; Yue, Wei; Aiyar, Sarah; Gompel, Anne; Wang, Ji-Ping; Tekmal, Rajeshwar Rao; Santen, Richard J

    2008-09-01

    Measurement of breast tissue estradiol levels could provide a powerful method to predict the risk of developing breast cancer but obtaining sufficient amounts of tissue from women is difficult from a practical standpoint. Assessment of aromatase in ductal lavage fluid or fine needle aspirates from breast might provide a surrogate marker for tissue estrogen levels but highly sensitive methods would be required. These considerations prompted us to develop an ultra-sensitive, "nested" PCR assay for aromatase which is up to one million fold more sensitive than standard PCR methods. We initially validated this assay using multiple tissues from the aromatase transgenic mouse and found that coefficients of variation for measurement of replicate samples averaged less than 5%. We demonstrated a 60-fold enhancement in aromatase message in the transgenic versus the wild type mouse breast but surprisingly, levels in the transgenic animals were highly variable, ranging from 0.4 to 27 relative units. The variability of aromatase expression in the transgenic breast did not correlate with the degree of breast development and did not appear to relate to hormonal manipulation of the MMTV promoter but probably related to lack of exhaustive inbreeding and mixed zygocity of transgenic animals. Extensive validation in mouse tissues provided confidence regarding the assay in human tissues, since nearly identical methods were used. The human assay was sufficiently sensitive to detect aromatase in a single human JAR (choriocarcinoma) cell, in all breast biopsies measured, and in 7/23 ductal lavage fluids. PMID:17975728

  13. High-sensitivity Q-band electron spin resonance imaging system with submicron resolution.

    PubMed

    Shtirberg, Lazar; Twig, Ygal; Dikarov, Ekaterina; Halevy, Revital; Levit, Michael; Blank, Aharon

    2011-04-01

    A pulsed electron spin resonance (ESR) microimaging system operating at the Q-band frequency range is presented. The system includes a pulsed ESR spectrometer, gradient drivers, and a unique high-sensitivity imaging probe. The pulsed gradient drivers are capable of producing peak currents ranging from ?9 A for short 150 ns pulses up to more than 94 A for long 1400 ns gradient pulses. Under optimal conditions, the imaging probe provides spin sensitivity of ?1.6 × 10(8) spins??Hz or ?2.7 × 10(6) spins for 1 h of acquisition. This combination of high gradients and high spin sensitivity enables the acquisition of ESR images with a resolution down to ?440 nm for a high spin concentration solid sample (?10(8) spins??m(3)) and ?6.7 ?m for a low spin concentration liquid sample (?6 × 10(5) spins/?m(3)). Potential applications of this system range from the imaging of point defects in crystals and semiconductors to measurements of oxygen concentration in biological samples. PMID:21529014

  14. PARP inhibition sensitizes childhood high grade glioma, medulloblastoma and ependymoma to radiation

    PubMed Central

    van Vuurden, Dannis G.; Hulleman, Esther; Meijer, Olga L.M.; Wedekind, Laurine E.; Kool, Marcel; Witt, Hendrik; Vandertop, Peter W. Peter; Würdinger, Thomas; Noske, David P.; Kaspers, Gertjan J.L.; Cloos, Jacqueline

    2011-01-01

    Poly ADP-ribose polymerase (PARP) is a protein involved in single strand break repair. Recently, PARP inhibitors have shown considerable promise in the treatment of several cancers, both in monotherapy and in combination with cytotoxic agents. Synthetic lethal action of PARP inhibitors has been observed in tumors with mutations in double strand break repair pathways. In addition, PARP inhibition potentially enhances sensitivity of tumor cells to DNA damaging agents, including radiotherapy. Aim of this study is to determine the radiosensitizing properties of the PARP inhibitor Olaparib in childhood medulloblastoma, ependymoma and high grade glioma (HGG). Increased PARP1 expression was observed in medulloblastoma, ependymoma and HGG, as compared to non-neoplastic brain tissue. Pediatric high grade glioma, medulloblastoma and ependymoma gene expression profiling revealed that high PARP1 expression is associated with poor prognosis. Cell growth inhibition assays with Olaparib resulted in differential sensitivity, with IC50 values ranging from 1.4 to 8.4 ?M, irrespective of tumor type and PARP1 protein expression. Sensitization to radiation was observed in medulloblastoma, ependymoma and HGG cell lines with subcytotoxic concentrations of Olaparib, which coincided with persistence of double strand breaks. Combining PARP inhibitors with radiotherapy in clinical studies in childhood high grade brain tumors may improve therapeutic outcome. PMID:22184287

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

    PubMed

    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, Mônica A

    2012-01-01

    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

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

    SciTech Connect

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

    2010-12-01

    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.

  17. Sensitive and selective tumor imaging with novel and highly activatable fluorescence strategies

    NASA Astrophysics Data System (ADS)

    Urano, Yasuteru

    2008-02-01

    Nowadays, several tumor imaging modalities such as MRI, PET and fluorescence imaging techniques have been extensively investigated. One of the central problems associated with these conventional tumor-targeted imaging methods, however, is the fact that the signal contrast between tumor and surrounding tissues relies on the efficient targeting to the tumor and the rapid sequestration or excretion of unbound agent. Among these modalities, only fluorescence imaging technique has a significant feature, in that great signal activation could be achieved which potentially leads to the selective imaging of cancer with higher tumor-to-background ratio. In this symposium, I will present some examples of fluorescence cancer imaging based on highly activatable strategies with using precisely designed novel fluorescence probes. Recently, we developed highly sensitive fluorescence probes for ?-galactosidase which is applicable for living cell system. By utilizing these probes, we could establish a novel and highly activatable strategy for sensitive and selective optical imaging of imbedded tumor in the peritoneum. We took a two step procedure in that a lectin is used to localize ?-galactosidase to cancer cells as an activating enzyme, and subsequent administration of a highly-sensitive fluorescence probe for the enzyme have afforded remarkable fluorescence activation selectively in tumor mass. Since the tumor-targeted enzyme can catalyze numerous substrate turnovers, a great number of fluorescent molecules could be produced and hence the rapid and sensitive detection of tumor in vivo with high tumor-to-background ratio could be achieved. Moreover, the consequent close-up investigation using fluorescence microscopy revealed that cancer microfoci as small as 200 ?m could be successfully visualized.

  18. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    Microsoft Academic Search

    Tara Grauwet; Iesel Van der Plancken; Liesbeth Vervoort; Ariette Matser; Marc Hendrickx; Ann Van Loey

    2011-01-01

    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be optimized. To this end, this work aimed at the development of an ovomucoid-based indicator with combined pressure temperature dependent inactivation kinetics and a sufficient

  19. Highly H+-sensitive neurons in the caudal ventrolateral medulla of the rat

    PubMed Central

    Ribas-Salgueiro, J L; Gaytán, S P; Crego, R; Pásaro, R; Ribas, J

    2003-01-01

    The ventral surface of the caudal ventrolateral medulla (cVLM) has been shown to generate intense respiratory responses after surface acid-base stimulation. With respect to their chemosensitive characteristics, cVLM neurons have been less studied than other rostral-most regions of the brainstem. The purpose of these experiments was to determine the bioelectric responses of cVLM neurons to acidic stimuli and to determine their chemosensitive properties. Using extracellular and microiontophoretic techniques, we recorded electrical activities from 117 neurons in an area close to the ventral surface of the cVLM in anaesthetised rats. All neurons were tested for their sensitivity to H+. The fluorescent probe BCECF was used to measure extracellular pH changes produced by the microiontophoretic injection of H+ in brainstem slices. This procedure provided an estimation of the local changes in pH produced by microiontophoretic H+ application in the anaesthetised rat. Neurons coupled to the respiratory cycle, R (n = 51), were not responsive to direct stimulation with H+. Sixty-six neurons that did respond to H+ stimulation were uncoupled from respiration, and identified as NR neurons. These neurons presented distinct ranges of H+ sensitivity. The neuronal sensitivity to H+ was mainly assessed by the slope of the stimulus-response curve, where the steeper the slope, the higher the H+ sensitivity. On this basis, NR neurons were classed as being either weakly or highly sensitive to H+. NR neurons with a high H+ sensitivity (n = 12) showed an average value of 34.17 ± 7.44 spikes s?1 (100 nC)?1 (mean ± s.d.) for maximal slope and an EC50 of 126.76 ± 33 nC. Suprathreshold H+ stimulation of highly sensitive NR neurons elicited bursting pattern responses coupled to the respiratory cycle. The bursting responses, which were synchronised with the inspiratory phase and the early expiratory phase of the respiratory cycle, lasted for several seconds before returning to the steady state firing pattern characteristic of the pre-stimulus condition. These NR neurons, which possess the capacity to detect distinct H+ concentrations in the extracellular microenvironment, are excellent candidates to serve in a chemoreceptor capacity in the caudal medulla. PMID:12665611

  20. High speed and nonvolatile Si nanocrystal memory for scaled flash technology using highly field-sensitive tunnel barrier

    Microsoft Academic Search

    Seung Jae Baik; Siyoung Choi; U-In Chung; Joo Tae Moon

    2003-01-01

    For the first time, a nitride\\/oxide\\/nitride stacked tunnel structure is adopted as highly field-sensitive tunnel barrier to improve both program\\/erase speed and data retention of nanocrystal memory. Product-adaptive nonvolatility (>10 years at 85°C) and cycling endurance (>106) were obtained with the program time of 10 ?s at VG=8 V and the erase time of 100 ?s at VG=-8 V with

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

    DOEpatents

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

    1999-08-24

    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.

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

    DOEpatents

    Pipino, Andrew Charles Rule (Gaithersburg, MD)

    1999-11-16

    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.

  3. Highly stretchable and wearable graphene strain sensors with controllable sensitivity for human motion monitoring.

    PubMed

    Park, Jung Jin; Hyun, Woo Jin; Mun, Sung Cik; Park, Yong Tae; Park, O Ok

    2015-03-25

    Because of their outstanding electrical and mechanical properties, graphene strain sensors have attracted extensive attention for electronic applications in virtual reality, robotics, medical diagnostics, and healthcare. Although several strain sensors based on graphene have been reported, the stretchability and sensitivity of these sensors remain limited, and also there is a pressing need to develop a practical fabrication process. This paper reports the fabrication and characterization of new types of graphene strain sensors based on stretchable yarns. Highly stretchable, sensitive, and wearable sensors are realized by a layer-by-layer assembly method that is simple, low-cost, scalable, and solution-processable. Because of the yarn structures, these sensors exhibit high stretchability (up to 150%) and versatility, and can detect both large- and small-scale human motions. For this study, wearable electronics are fabricated with implanted sensors that can monitor diverse human motions, including joint movement, phonation, swallowing, and breathing. PMID:25735398

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

    NASA Astrophysics Data System (ADS)

    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

    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.

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

    NASA Astrophysics Data System (ADS)

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

    2012-03-01

    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.

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

    SciTech Connect

    Duden, Thomas; Radmilovic, Velimir

    2009-03-04

    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.

  7. Silicene as a highly sensitive molecule sensor for NH3, NO and NO2.

    PubMed

    Hu, Wei; Xia, Nan; Wu, Xiaojun; Li, Zhenyu; Yang, Jinlong

    2014-04-21

    On the basis of first-principles calculations, we demonstrate the potential application of silicene as a highly sensitive molecule sensor for NH3, NO, and NO2 molecules. NH3, NO and NO2 molecules chemically adsorb on silicene via strong chemical bonds. With distinct charge transfer from silicene to molecules, silicene and chemisorbed molecules form charge-transfer complexes. The adsorption energy and charge transfer in NO2-adsorbed silicene are larger than those of NH3- and NO-adsorbed silicones. Depending on the adsorbate types and concentrations, the silicene-based charge-transfer complexes exhibit versatile electronic properties with tunable band gap opening at the Dirac point of silicene. The calculated charge carrier concentrations of NO2-chemisorbed silicene are 3 orders of magnitude larger than intrinsic charge carrier concentration of graphene at room temperature. The results present a great potential of silicene for application as a highly sensitive molecule sensor. PMID:24595614

  8. Silicon on-chip bandpass filters for the multiplexing of high sensitivity photonic crystal microcavity biosensors

    NASA Astrophysics Data System (ADS)

    Yan, Hai; Zou, Yi; Chakravarty, Swapnajit; Yang, Chun-Ju; Wang, Zheng; Tang, Naimei; Fan, Donglei; Chen, Ray T.

    2015-03-01

    A method for the dense integration of high sensitivity photonic crystal (PC) waveguide based biosensors is proposed and experimentally demonstrated on a silicon platform. By connecting an additional PC waveguide filter to a PC microcavity sensor in series, a transmission passband is created, containing the resonances of the PC microcavity for sensing purpose. With proper engineering of the passband, multiple high sensitivity PC microcavity sensors can be integrated into microarrays and be interrogated simultaneously between a single input and a single output port. The concept was demonstrated with a 2-channel L55 PC biosensor array containing PC waveguide filters. The experiment showed that the sensors on both channels can be monitored simultaneously from a single output spectrum. Less than 3 dB extra loss for the additional PC waveguide filter is observed.

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

    PubMed

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

    2013-05-20

    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

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

    NASA Astrophysics Data System (ADS)

    Hacker, J.; Wile, S.

    2013-12-01

    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.

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

    E-print Network

    Takeuchi, Yasuo

    ) to monitor the SK puri#12;ed water. The detection limit of the 70L radon detector for water was suÆcient for previous studies. However, the detection limit for the SK degasi#12;ed water was about 6 mBq=m 3 , higher-high sensitivity radon detector for water which works as a real-time monitor of the radon concentration in water

  12. Novel luminescent Ir(III) dyes for developing highly sensitive oxygen sensing films

    Microsoft Academic Search

    M. Marin-Suarezdel Toro; J. F. Fernandez-Sanchez; E. Baranoff; M. Graetzel; A. Fernandez-Gutierrez

    2010-01-01

    New sensing films have been developed for the detection of molecular oxygen. These films are based on luminescent Ir(III) dyes incorporated either into polystyrene (with and without plasticizer) or metal oxide, nanostructured material. The preparation and characterization of each film have been investigated in detail. Due to their high sensitivity for low oxygen concentration, the parameters pO2(S=1\\/2) and ?I1% have

  13. A low-noise high-sensitivity readout circuit for MEMS capacitive sensors

    Microsoft Academic Search

    Jack Shiah; Hooman Rashtian; Shahriar Mirabbasi

    2010-01-01

    This paper presents a differential low-noise high-resolution switched-capacitor readout circuit that is intended for capacitive sensors. Amplitude modulation\\/demodulation and correlated double sampling are used to minimize the adverse effects of the amplifier offset and flicker (1\\/f) noise and improve the sensitivity of the readout circuit. In order to simulate the response of the readout circuit, a Verilog-A model is used

  14. Dyes designed for high sensitivity detection of double-stranded DNA

    DOEpatents

    Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Oakland, CA)

    2000-01-01

    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.

  15. Dyes designed for high sensitivity detection of double-stranded DNA

    DOEpatents

    Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Oakland, CA)

    1998-01-01

    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.

  16. A highly sensitive spectrophotometric determination of platinum(IV) using leuco xylene cyanol FF

    Microsoft Academic Search

    H. D. Revanasiddappa; Kiran T. Kumar

    2003-01-01

    A new, simple, highly sensitive and rapid spectrophotometric method has been described for the determination of platinum(IV). The method is based on the oxidation of leuco xylene cyanol FF (LXCFF) to its blue form of xylene cyanol FF by platinum(IV) in sulfuric acid medium (pH 1.0-2.5), the formed dye shows an absorption maximum at 620 nm in acetate buffer medium

  17. High frame-rate imaging of surface pressure distribution using a porous pressure-sensitive paint

    Microsoft Academic Search

    Y. Sakamura; M. Matsumoto; T. Suzuki

    2005-01-01

    The aim of the present work is to demonstrate the feasibility of a porous pressure-sensitive paint (PSP) for time-resolved surface pressure measurements in unsteady high-speed flows. The porous PSP was composed of bathophenanthroline ruthenium(II) complex, Ru(Ph2-phen) and a silica-gel thin-layer chromatography aluminium plate. The dynamic response of the porous PSP was characterized by a point-wise luminescence intensity measurement conducted in

  18. Dyes designed for high sensitivity detection of double-stranded DNA

    DOEpatents

    Glazer, Alexander N. (Orinda, CA); Benson, Scott C. (Albany, CA)

    1994-01-01

    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.

  19. Dyes designed for high sensitivity detection of double-stranded DNA

    DOEpatents

    Glazer, A.N.; Benson, S.C.

    1998-07-21

    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.

  20. A new reagent system for the highly sensitive spectrophotometric determination of selenium

    Microsoft Academic Search

    Hosakere D. Revanasiddappa; Banadahalli P. Dayananda

    2006-01-01

    Highly sensitive and simple spectrophotometric determination of selenium is described for the determination of selenium(IV)\\u000a using a new reagent leuco malachite green. The method is based on the reaction of selenium(IV) with potassium iodide in an\\u000a acidic condition to liberate iodine, the liberated iodine oxidizes leuco malachite green to malachite green dye. The green\\u000a coloration was developed in an acetate

  1. Development of a high sensitivity, nested Q-PCR assay for mouse and human aromatase

    Microsoft Academic Search

    Giujian Liu; Yu-sheen Wu; David Brenin; Wei Yue; Sarah Aiyar; Anne Gompel; Ji-Ping Wang; Rajeshwar Rao Tekmal; Richard J. Santen

    2008-01-01

    Measurement of breast tissue estradiol levels could provide a powerful method to predict the risk of developing breast cancer\\u000a but obtaining sufficient amounts of tissue from women is difficult from a practical standpoint. Assessment of aromatase in\\u000a ductal lavage fluid or fine needle aspirates from breast might provide a surrogate marker for tissue estrogen levels but highly\\u000a sensitive methods would

  2. Highly sensitive and specific microRNA expression profiling using BeadArray technology

    Microsoft Academic Search

    Jing Chen; Jean Lozach; Eliza Wickham Garcia; Bret Barnes; Shujun Luo; Ivan Mikoulitch; Lixin Zhou; Gary Schroth; Jian-Bing Fan

    2008-01-01

    We have developed a highly sensitive, specific and reproducible method for microRNA (miRNA) expres- sion profiling, using the BeadArrayTM technology. This method incorporates an enzyme-assisted spe- cificity step, a solid-phase primer extension to dis- tinguish between members of miRNA families. In addition, a universal PCR is used to amplify all tar- gets prior to array hybridization. Currently, assay probes are

  3. Gold nanoparticle/polymer nanocomposite for highly sensitive drug-DNA interaction.

    PubMed

    Kuralay, F; Erdem, A

    2015-04-21

    The interaction of the anticancer drug mitomycin C (MC) and DNA immobilized on gold a nanoparticle/polyvinylferrocenium (AuNP/PVF(+)) coated electrode is presented. This is the first attempt to prepare a biocompatible nanoparticle/redox polymer composite in a one-step and easy electropolymerization procedure and then use the coated electrode for MC-DNA interaction. The prepared electrode exhibits high sensitivity for the investigation of drug-DNA interaction. PMID:25743103

  4. Future detectability of gravitational-wave induced lensing from high-sensitivity CMB experiments

    NASA Astrophysics Data System (ADS)

    Namikawa, Toshiya; Yamauchi, Daisuke; Taruya, Atsushi

    2015-02-01

    We discuss the future detectability of gravitational-wave induced lensing from high-sensitivity cosmic microwave background (CMB) experiments. Gravitational waves can induce a rotational component of the weak-lensing deflection angle, usually referred to as the curl mode, which would be imprinted on the CMB maps. Using the technique of reconstructing lensing signals involved in CMB maps, this curl mode can be measured in an unbiased manner, offering an independent confirmation of the gravitational waves complementary to B-mode polarization experiments. Based on the Fisher matrix analysis, we first show that with the noise levels necessary to confirm the consistency relation for the primordial gravitational waves, the future CMB experiments will be able to detect the gravitational-wave induced lensing signals. For a tensor-to-scalar ratio of r ?0.1 , even if the consistency relation is difficult to confirm with a high significance, the gravitational-wave induced lensing will be detected at more than 3 ? significance level. Further, we point out that high-sensitivity experiments will be also powerful to constrain the gravitational waves generated after the recombination epoch. Compared to the B-mode polarization, the curl mode is particularly sensitive to gravitational waves generated at low redshifts (z ?10 ) with a low frequency (k ?1 0-3 Mpc-1 ), and it could give a much tighter constraint on their energy density ?GW by more than 3 orders of magnitude.

  5. Effect of high altitude on sensitivity to the taste of phenylthiocarbamide

    NASA Astrophysics Data System (ADS)

    Singh, S. B.; Chatterjee, A.; Panjwani, U.; Yadav, D. K.; Selvamurthy, W.; Sharma, K. N.

    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.

  6. Effect of high altitude on sensitivity to the taste of phenylthiocarbamide.

    PubMed

    Singh, S B; Chatterjee, A; Panjwani, U; Yadav, D K; Selvamurthy, W; Sharma, K N

    2000-05-01

    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. PMID:10879424

  7. A highly sensitive magnetic biosensor for detection and quantification of anticancer drugs tagged to superparamagnetic nanoparticles

    NASA Astrophysics Data System (ADS)

    Devkota, J.; Wingo, J.; Mai, T. T. T.; Nguyen, X. P.; Huong, N. T.; Mukherjee, P.; Srikanth, H.; Phan, M. H.

    2014-05-01

    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.

  8. Highly sensitive hydrogen sulfide (H?S) gas sensors from viral-templated nanocrystalline gold nanowires.

    PubMed

    Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V; Haberer, Elaine D

    2014-04-01

    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

  9. High Steroid Sensitivity among Children with Nephrotic Syndrome in Southwestern Nigeria

    PubMed Central

    Ladapo, Taiwo Augustina; Esezobor, Christopher Imokhuede; Lesi, Foluso Ebun

    2014-01-01

    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

  10. Highly sensitive hydrogen sulfide (H2 S) gas sensors from viral-templated nanocrystalline gold nanowires

    NASA Astrophysics Data System (ADS)

    Moon, Chung Hee; Zhang, Miluo; Myung, Nosang V.; Haberer, Elaine D.

    2014-04-01

    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%/ppmv, theoretical lowest detection limit of 2 ppbv, and 70% recovery within 9 min for 0.025 ppmv. The role of the viral template and associated gold-binding peptide was elucidated by removing organics using a short O2 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%/ppmv, 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.

  11. MOSFET sensitivity dependence on integrated dose from high-energy photon beams.

    PubMed

    Tanyi, James A; Krafft, Shane P; Hagio, Tomoe; Fuss, Martin; Salter, Bill J

    2008-01-01

    The ability of a commercially available dual bias, dual MOSFET dosimetry system to measure therapeutic doses reproducibly throughout its vendor-defined dose-based lifetime has been evaluated by characterizing its sensitivity variation to integrated/cumulative doses from,high-energy (6 and 15 MV) photon radiotherapy beams. The variation of sensitivity as a function of total integrated dose was studied for three different dose-per-fraction levels; namely, 50, 200, and 1200 cGy/fraction. In standard sensitivity mode (i.e., measurements involving dose-per-fraction levels > or =100 cGy), the response of the MOSFET system to identical irradiations increased with integrated dose for both energies investigated. Dose measurement reproducibility for the low (i.e., 50 cGy) dose fractions was within 2.1% (if the system was calibrated before each in-phantom measurement) and 3.1% [if the system was calibrated prior to first use, with no intermediate calibration(s)]. Similarly, dose measurement reproducibility was between 2.2% and 6.6% for the conventional (i.e., 200 cGy) dose fractions and between 1.8% and 7.9% for escalated (i.e., 1200 cGy) dose fractions. The results of this study suggest that, due to the progressively increasing sensitivity resulting from the dual-MOSFET design, frequent calibrations are required to achieve measurement accuracy of < or =3% (within one standard deviation). PMID:18293559

  12. Performance Sensitivity Studies on the PIAA Implementation of the High-Contrast Imaging Testbed

    NASA Technical Reports Server (NTRS)

    Sidick, Erkin; Lou, John; Shaklan, Stuart; Levine, Marie

    2010-01-01

    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

  13. Highly sensitive antenna using inkjet overprinting with particle-free conductive inks.

    PubMed

    Komoda, Natsuki; Nogi, Masaya; Suganuma, Katsuaki; Otsuka, Kanji

    2012-11-01

    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

  14. Development of a high-sensitivity 80 L radon detector for purified gases

    NASA Astrophysics Data System (ADS)

    Hosokawa, K.; Murata, A.; Nakano, Y.; Onishi, Y.; Sekiya, H.; Takeuchi, Y.; Tasaka, S.

    2015-03-01

    In underground particle physics experiments, the radioactive noble gas ^{222}Rn generated from the decay chain of the uranium series could be a serious background source. We have been developing high-sensitivity radon detectors to assay radon in the Kamioka underground laboratory. In order to achieve a further low background level, we developed a new radon detector with better hermeticity. The high-voltage dependence and humidity dependence of the detection efficiencies were obtained through our calibration systems. The background level of the new radon detector was also measured.

  15. Highly Sensitive, Highly Specific Whole-Cell Bioreporters for the Detection of Chromate in Environmental Samples

    PubMed Central

    Branco, Rita; Cristóvão, Armando; Morais, Paula V.

    2013-01-01

    Microbial bioreporters offer excellent potentialities for the detection of the bioavailable portion of pollutants in contaminated environments, which currently cannot be easily measured. This paper describes the construction and evaluation of two microbial bioreporters designed to detect the bioavailable chromate in contaminated water samples. The developed bioreporters are based on the expression of gfp under the control of the chr promoter and the chrB regulator gene of TnOtChr determinant from Ochrobactrum tritici 5bvl1. pCHRGFP1 Escherichia coli reporter proved to be specific and sensitive, with minimum detectable concentration of 100 nM chromate and did not react with other heavy metals or chemical compounds analysed. In order to have a bioreporter able to be used under different environmental toxics, O. tritici type strain was also engineered to fluoresce in the presence of micromolar levels of chromate and showed to be as specific as the first reporter. Their applicability on environmental samples (spiked Portuguese river water) was also demonstrated using either freshly grown or cryo-preserved cells, a treatment which constitutes an operational advantage. These reporter strains can provide on-demand usability in the field and in a near future may become a powerful tool in identification of chromate-contaminated sites. PMID:23326558

  16. Optimization of X-ray phase contrast imaging system toward high-sensitivity measurements of biological organs

    SciTech Connect

    Hoshino, Masato; Uesugi, Kentaro; Yagi, Naoto [Japan Synchrotron Radiation Research Institute (JASRI/SPring-8) (Japan)

    2012-07-31

    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.

  17. From maps to movies: High resolution time-varying sensitivity analysis for spatially distributed watershed models

    NASA Astrophysics Data System (ADS)

    Herman, J. D.; Kollat, J. B.; Reed, P. M.; Wagener, T.

    2013-12-01

    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.

  18. From maps to movies: high resolution time-varying sensitivity analysis for spatially distributed watershed models

    NASA Astrophysics Data System (ADS)

    Herman, J. D.; Kollat, J. B.; Reed, P. M.; Wagener, T.

    2013-08-01

    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.

  19. Ultra-high-speed phase-sensitive optical coherence reflectometer with a stretched pulse supercontinuum source.

    PubMed

    Song, Hoseong; Cho, Seung Bum; Kim, Dong Uk; Jeong, Sungho; Kim, Dug Young

    2011-07-20

    We demonstrate an ultra-high-speed phase-sensitive time-wavelength-domain optical coherence reflectometer with a stretched pulse supercontinuum source. A pulsed fiber laser operating at 10 MHz repetition rate was used to generate a pulsed supercontinuum of 30 ps pulse duration by using a nonlinear optical fiber. The supercontinuum pulses are stretched into 70 ns pulses with a highly dispersive fiber. With this stretched pulse source, we have built a phase-sensitive optical coherence reflectometer that measures the spectral interferogram of reflected light. By using the linear relation between the wavelength and the temporal position in a linearly chirped pulse, ultra-high-speed spectrum measurement can be obtained with this method in the time domain. We have demonstrated ultra-high-speed two-dimensional surface profiling for a standard image target and high-speed single-point monitoring for a fixed point under vibrational motion. It is shown that the measurement speed for the position of a single point can be as fast as 2.5 MHz, while the position accuracy can be better than 4.49 nm. PMID:21772383

  20. Highly sensitive operation of intensity-based fiber-optic vibration sensor using cascaded long period fiber grating

    NASA Astrophysics Data System (ADS)

    Tanaka, Satoshi; Tsukida, Osamu; Takeuchi, Makoto; Tekuramori, Shingo; Uchimura, Ryotaro; Wada, Atsushi; Takahashi, Nobuaki

    2014-05-01

    A highly sensitive fiber-optic mechanical vibration sensor is constructed by using a cascaded long period fiber grating (LPG) based on an intensity modulation scheme. In the fabrication process, the cascaded LPG, which is composed of a pair of identical LPGs with a certain distance, is inscribed in a length of photosensitive single-mode optical fiber by means of a point-by-point technique using a KrF excimer laser. Since the sensitivity of the intensity-based LPG sensor depends on a gradient of the slope of transmittance spectrum curve as well as the strain-sensitivity of the spectral shift, the channeled spectrum of the cascaded LPG provides a highly sensitive operation for the vibration detection. In the experiment, several kinds of cascaded LPGs have been fabricated and examined in terms of the sensor sensitivity. In addition, highly sensitive mechanical vibration detection has been successfully demonstrated.

  1. Future detectability of gravitational-wave induced lensing from high-sensitivity CMB experiments

    E-print Network

    Toshiya Namikawa; Daisuke Yamauchi; Atsushi Taruya

    2015-03-03

    We discuss the future detectability of gravitational-wave induced lensing from high-sensitivity cosmic microwave background (CMB) experiments. Gravitational waves can induce a rotational component of the weak-lensing deflection angle, usually referred to as the curl mode, which would be imprinted on the CMB maps. Using the technique of reconstructing lensing signals involved in CMB maps, this curl mode can be measured in an unbiased manner, offering an independent confirmation of the gravitational waves complementary to the B-mode polarization experiments. Based on the Fisher matrix analysis, we first show that with the noise levels necessary to confirm the consistency relation for the primordial gravitational waves, the future CMB experiments will be able to detect the gravitational-wave induced lensing signals. For a tensor-to-scalar ratio of $r induced lensing would be detected at more than $3\\,\\sigma$ significance level. Further, we point out that high-sensitivity experiments will be also powerful to constrain the gravitational waves generated after the recombination epoch. Compared to the B-mode polarization, the curl mode is particularly sensitive to gravitational waves generated at low redshifts ($z < 10$) with a low frequency ($k < 10^{-3}$ Mpc$^{-1}$), and it could give a much tighter constraint on their energy density $\\Omega_{\\rm GW}$ by more than three orders of magnitude.

  2. Determination of chlorinated hydrocarbons in water using highly sensitive mid-infrared sensor technology.

    PubMed

    Lu, Rui; Mizaikoff, Boris; Li, Wen-Wei; Qian, Chen; Katzir, Abraham; Raichlin, Yosef; Sheng, Guo-Ping; Yu, Han-Qing

    2013-01-01

    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

  3. Determination of Chlorinated Hydrocarbons in Water Using Highly Sensitive Mid-Infrared Sensor Technology

    PubMed Central

    Lu, Rui; Mizaikoff, Boris; Li, Wen-Wei; Qian, Chen; Katzir, Abraham; Raichlin, Yosef; Sheng, Guo-Ping; Yu, Han-Qing

    2013-01-01

    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

  4. Optical clearing method for monitoring cutaneous microcirculation response to vasoactive drugs with high sensitivity

    NASA Astrophysics Data System (ADS)

    Shi, Rui; Chen, Min; Wang, Ruilin; Ma, Cong; Jin, Junbo; Lu, Yuhua; Timoshina, Polina; Tuchin, Valery V.; Zhu, Dan

    2014-02-01

    Laser speckle contrast imaging technique has been playing an important role in monitoring cutaneous microcirculation, but the strong scattering of skin restricts the imaging depth and contrast, and also makes it impossible to assess the cutaneous microcirculation response dynamically with high sensitivity. The tissue optical clearing is helpful for opening a visible window on mouse dorsal skin. In this work, the cutaneous microcirculation response to vasoactive noradrenaline is monitored with the laser speckle contrast imaging system before and after skin optical clearing. The results show that the optical clearing method can significantly enhance the contrast of laser speckle contrast imaging, and small blood vessels whose diameter less than 20?m can be distinguished with high resolution. The dynamic changes in cutaneous microvascular diameter and blood flow velocity caused by drug can be monitored sensitively. In contrast, it is difficult to detect the cutaneous microcirculation response that occurred in the blood vessels more than 100?m in the intact skin, and the signal-to-noise ratio is too low to monitor the dynamic changes caused by the same drug. Thus, skin optical clearing method can enhance the ability of laser speckle contrast imaging in accessing cutaneous microcirculation response, including the imaging contrast, resolution and sensitivity.

  5. Sensitive high-throughput screening for the detection of reducing sugars.

    PubMed

    Mellitzer, Andrea; Glieder, Anton; Weis, Roland; Reisinger, Christoph; Flicker, Karlheinz

    2012-01-01

    The exploitation of renewable resources for the production of biofuels relies on efficient processes for the enzymatic hydrolysis of lignocellulosic materials. The development of enzymes and strains for these processes requires reliable and fast activity-based screening assays. Additionally, these assays are also required to operate on the microscale and on the high-throughput level. Herein, we report the development of a highly sensitive reducing-sugar assay in a 96-well microplate screening format. The assay is based on the formation of osazones from reducing sugars and para-hydroxybenzoic acid hydrazide. By using this sensitive assay, the enzyme loads and conversion times during lignocellulose hydrolysis can be reduced, thus allowing higher throughput. The assay is about five times more sensitive than the widely applied dinitrosalicylic acid based assay and can reliably detect reducing sugars down to 10 ?M. The assay-specific variation over one microplate was determined for three different lignocellulolytic enzymes and ranges from 2 to 8%. Furthermore, the assay was combined with a microscale cultivation procedure for the activity-based screening of Pichia pastoris strains expressing functional Thermomyces lanuginosus xylanase A, Trichoderma reesei ?-mannanase, or T. reesei cellobiohydrolase 2. PMID:21538898

  6. High sensitivity multiplex short tandem repeat loci analyses with massively parallel sequencing.

    PubMed

    Zeng, Xiangpei; King, Jonathan L; Stoljarova, Monika; Warshauer, David H; LaRue, Bobby L; Sajantila, Antti; Patel, Jaynish; Storts, Douglas R; Budowle, Bruce

    2015-05-01

    STR typing in forensic genetics has been performed traditionally using capillary electrophoresis (CE). However, CE-based method has some limitations: a small number of STR loci can be used; stutter products, dye artifacts and low level alleles. Massively parallel sequencing (MPS) has been considered a viable technology in recent years allowing high-throughput coverage at a relatively affordable price. Some of the CE-based limitations may be overcome with the application of MPS. In this study, a prototype multiplex STR System (Promega) was amplified and prepared using the TruSeq DNA LT Sample Preparation Kit (Illumina) in 24 samples. Results showed that the MinElute PCR Purification Kit (Qiagen) was a better size selection method compared with recommended diluted bead mixtures. The library input sensitivity study showed that a wide range of amplicon product (6-200ng) could be used for library preparation without apparent differences in the STR profile. PCR sensitivity study indicated that 62pg may be minimum input amount for generating complete profiles. Reliability study results on 24 different individuals showed that high depth of coverage (DoC) and balanced heterozygote allele coverage ratios (ACRs) could be obtained with 250pg of input DNA, and 62pg could generate complete or nearly complete profiles. These studies indicate that this STR multiplex system and the Illumina MiSeq can generate reliable STR profiles at a sensitivity level that competes with current widely used CE-based method. PMID:25528025

  7. [The clinical role of high-sensitive troponin assays: update, interpretation, and perspectives].

    PubMed

    Lippi, Giuseppe; Cervellin, Gianfranco

    2010-11-01

    More than thirty years have elapsed since the release of the first criteria of acute myocardial infarction defined by the WHO, but the diagnostic approach to the patients presenting with chest pain remains complex and controversial. Several diagnostic strategies have been proposed, characterized by a variety of algorithms and biochemical markers. The recent introduction of the new cardiac troponin assays, defined "highly-sensitive" and characterized by a higher analytic sensitivity, carries several advantages and some problems. These methods have allowed to identify the continuum of pathophysiological events ranging from an angina attack to the onset of a manifest myocardial infarction, as well as to drastically shorten the triage of the patients because minimum increments of the marker are appreciated much earlier than using the traditional assays. It is also predictable that the usefulness of these highly sensitive methods might be useful beyond the diagnosis of ischemic heart disease, especially for the prospective evaluation of the patients. Nevertheless, the drastic reduction of the diagnostic thresholds, which is a hallmark of this new generation of test, requires a more careful formulation of the reference intervals, a reassessment of the therapeutic strategies, and especially an accurate troubleshooting of the several causes of troponin abnormalities which are not associated with a clear clinical significance. In this context, a close partnership between the clinics and the laboratory is an essential aspect for the appropriate use of the tests and for the accurate interpretation of results. PMID:21197762

  8. FBG sensor for temperature-independent high sensitive pressure measurement with aid of a Bourdon tube

    NASA Astrophysics Data System (ADS)

    Srimannarayana, K.; Vengal Rao, P.; Sai Shankar, M.; Kishore, P.

    2014-05-01

    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.

  9. Performance of the high-sensitivity troponin assay in diagnosing acute myocardial infarction: systematic review and meta-analysis

    PubMed Central

    Al-Saleh, Ayman; Alazzoni, Ashraf; Al Shalash, Saleh; Ye, Chenglin; Mbuagbaw, Lawrence; Thabane, Lehana; Jolly, Sanjit S.

    2014-01-01

    Background High-sensitivity cardiac troponin assays have been adopted by many clinical centres worldwide; however, clinicians are uncertain how to interpret the results. We sought to assess the utility of these assays in diagnosing acute myocardial infarction (MI). Methods We carried out a systematic review and meta-analysis of studies comparing high-sensitivity with conventional assays of cardiac troponin levels among adults with suspected acute MI in the emergency department. We searched MEDLINE, EMBASE and Cochrane databases up to April 2013 and used bivariable random-effects modelling to obtain summary parameters for diagnostic accuracy. Results We identified 9 studies that assessed the use of high-sensitivity troponin T assays (n = 9186 patients). The summary sensitivity of these tests in diagnosing acute MI at presentation to the emergency department was estimated to be 0.94 (95% confidence interval [CI] 0.89–0.97); for conventional tests, it was 0.72 (95% CI 0.63–0.79). The summary specificity was 0.73 (95% CI 0.64–0.81) for the high-sensitivity assay compared with 0.95 (95% CI 0.93–0.97) for the conventional assay. The differences in estimates of the summary sensitivity and specificity between the high-sensitivity and conventional assays were statistically significant (p < 0.01). The area under the curve was similar for both tests carried out 3–6 hours after presentation. Three studies assessed the use of high-sensitivity troponin I assays and showed similar results. Interpretation Used at presentation to the emergency department, the high-sensitivity cardiac troponin assay has improved sensitivity, but reduced specificity, compared with the conventional troponin assay. With repeated measurements over 6 hours, the area under the curve is similar for both tests, indicating that the major advantage of the high-sensitivity test is early diagnosis. PMID:25295240

  10. Test and evaluation of a high-sensitivity assay system for bulk transuranic waste

    SciTech Connect

    Caldwell, J.T.; Close, D.A.; Kuckertz, T.H.; Kunz, W.E.; Pratt, J.C.; Haff, K.W.; Schultz, F.J.

    1983-01-01

    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.

  11. Highly sensitive and noise-protected adaptive optical microphone based on a dynamic photorefractive hologram

    NASA Astrophysics Data System (ADS)

    Romashko, R. V.; Kulchin, Y. N.; Nippolainen, E.

    2014-11-01

    We report a novel scheme of an adaptive optical microphone (AOM) based on two-wave mixing in a photorefractive crystal. The sensitive element of the microphone is a thin metal membrane which receives acoustic waves and modulates a light phase that is demodulated by means of a dynamic hologram continuously recorded in a photorefractive CdTe crystal. Due to the interferometric operation principle, the AOM possesses an ultra-high sensitivity to acoustic pressure (4.3?rad?Pa?1 at a frequency of 1?kHz), low detection threshold (0.79?mPa or 32?dB) and large dynamic range (55?dB), while the adaptive properties of a dynamic hologram allow one to perform a measurement in an unstable environment.

  12. Blue-Coloured Highly Efficient Dye-Sensitized Solar Cells by Implementing the Diketopyrrolopyrrole Chromophore

    PubMed Central

    Yum, Jun-Ho; Holcombe, Thomas W.; Kim, Yongjoo; Rakstys, Kasparas; Moehl, Thomas; Teuscher, Joel; Delcamp, Jared H.; Nazeeruddin, Mohammed K.; Grätzel, Michael

    2013-01-01

    The paradigm shift in dye sensitized solar cells (DSCs) – towards donor- ? bridge-acceptor (D-?-A) dyes – increases the performances of DSCs and challenges established design principles. Framed by this shifting landscape, a series of four diketopyrrolopyrrole (DPP)-based sensitizers utilizing the donor-chromophore-anchor (D-C-A) motif were investigated computationally, spectroscopically, and fabricated by systematic evaluation of finished photovoltaic cells. In all cases, the [Co(bpy)3]3+/2+ redox-shuttle afforded superior performance compared to I3?/I?. Aesthetically, careful molecular engineering of the DPP chromophore yielded the first example of a high-performance blue DSC – a challenge unmet since the inception of this photovoltaic technology: DPP17 yields over 10% power conversion efficiency (PCE) with the [Co(bpy)3]3+/2+ electrolyte at full AM 1.5?G simulated sun light. PMID:23945746

  13. A microfluidic electrochemical device for high sensitivity biosensing: detection of nanomolar hydrogen peroxide

    PubMed Central

    Chikkaveeraiah, Bhaskara V.; Liu, Hongyun; Mani, Vigneshwaran; Papadimitrakopoulos, Fotios; Rusling, James F.

    2009-01-01

    We report herein a simple device for rapid biosensing consisting of a single microfluidic channel made from poly(dimethylsiloxane) (PDMS) coupled to an injector, and incorporating a biocatalytic sensing electrode, reference and counter electrodes. The sensing electrode was a gold wire coated with 5 nm glutathione-decorated gold nanoparticles (AuNPs). Sensitive detection of H2O2 based on direct bioelectrocatalysis by horseradish peroxidase (HRP) was used for evaluation. HRP was covalently linked the glutathione-AuNPs. This electrode presented quasi-reversible cyclic voltammetry peaks at ?0.01 V vs Ag/AgCl at pH 6.5 for the HRP heme FeIII/FeII couple. Direct electrochemical activity of HRP was used to detect H2O2 at high sensitivity with a detection limit of 5 nM in an unmediated system. PMID:20161158

  14. A Small Mission Featuring an Imaging X-ray Polarimeter with High Sensitivity

    NASA Technical Reports Server (NTRS)

    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

    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.

  15. Highly sensitive and selective odorant sensor using living cells expressing insect olfactory receptors

    PubMed Central

    Misawa, Nobuo; Mitsuno, Hidefumi; Kanzaki, Ryohei; Takeuchi, Shoji

    2010-01-01

    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

  16. Small-angle measurement with highly sensitive total-internal-reflection heterodyne interferometer.

    PubMed

    Lin, Jiun-You; Liao, Yu-Cheng

    2014-03-20

    In this paper, a high-sensitivity total-internal-reflection (TIR) heterodyne interferometer is proposed for measuring small angles. In the proposed interferometer, a half-wave plate and two quarter-wave plates that exhibit specific optic-axis azimuths are combined to form a phase shifter. When a rhomboid prism is placed between the phase shifter and an analyzer that exhibits suitable transmission-axis azimuth, it shifts and enhances the phase difference of the s- and p-polarization states at double TIR. The enhanced phase difference is dependent on the incident angle; thus small angles can be easily and accurately measured by estimating the phase difference. The experimental results demonstrate the feasibility of this method. Angular resolution and sensitivity levels superior to 1.2×10?? deg (2.1×10?? rad) and 100 (deg/deg), respectively, were attainable in a dynamic range of 0.5 deg. PMID:24663469

  17. Application of strong transverse magneto-optical Kerr effect on high sensitive surface plasmon grating sensors.

    PubMed

    Chou, Kuei-Hsu; Lin, En-Ping; Chen, Te-Chang; Lai, Chih-Huang; Wang, Liang-Wei; Chang, Ko-Wei; Lee, Gwo-Bin; Lee, Ming-Chang M

    2014-08-11

    A high sensitive sensor is demonstrated by exploiting strong transverse magneto-optical Kerr effect on a ferromagnetic surface plasmon grating. The surface plasmon grating, made of a hybridized Au/Fe/Au layer, exhibits a very dispersive Kerr parameter variation near the surface plasmon polariton (SPP) wavelength via coherent scattering of the SPP on the grating structure. Interrogating this Kerr parameter can be utilized for detecting chemical or biological objects in a fluid medium. The experiment results show the minimal detectable mass concentration of sodium chloride in a saline solution is 4.27 × 10(-3) %, corresponding to a refractive index change of 7.60 × 10(-6) RIU. For an avidin-biotin interaction experiment, the sensitivity of avidin detection in PBS solution is 1.97 nM, which is limited by the index fluctuation of flowing media during measurement. PMID:25321061

  18. Graphene enhanced evanescent field in microfiber multimode interferometer for highly sensitive gas sensing.

    PubMed

    Yao, B C; Wu, Y; Zhang, A Q; Rao, Y J; Wang, Z G; Cheng, Y; Gong, Y; Zhang, W L; Chen, Y F; Chiang, K S

    2014-11-17

    Graphene based new physics phenomena are leading to a variety of stimulating graphene-based photonic devices. In this study, the enhancement of surface evanescent field by graphene cylindrical cladding is observed, for the first time, by using a graphene-coated microfiber multi-mode interferometer (GMMI). It is found theoretically and experimentally that the light transmitting in the fiber core is efficiently dragged by the graphene, hence significantly enhancing the evanescent fields, and subsequently improving the sensitivity of the hybrid waveguide. The experimental results for gas sensing verified the theoretical prediction, and ultra-high sensitivities of ~0.1 ppm for NH(3) gas detection and ~0.2 ppm for H(2)O vapor detection are achieved, which could be used for trace analysis. The enhancement of surface evanescent field induced by graphene may pave a new way for developing novel graphene-based all-fiber devices with compactness, low cost, and temperature immunity. PMID:25402055

  19. High-sensitivity detection of triacetone triperoxide (TATP) and its precursor acetone

    NASA Astrophysics Data System (ADS)

    Dunayevskiy, Ilya; Tsekoun, Alexei; Prasanna, Manu; Go, Rowel; Patel, C. Kumar N.

    2007-09-01

    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.

  20. High sensitivity piezomagnetic force microscopy for quantitative probing of magnetic materials at the nanoscale.

    PubMed

    Chen, Qian Nataly; Ma, Feiyue; Xie, Shuhong; Liu, Yuanming; Proksch, Roger; Li, Jiangyu

    2013-07-01

    Accurate scanning probing of magnetic materials at the nanoscale is essential for developing and characterizing magnetic nanostructures, yet quantitative analysis is difficult using the state of the art magnetic force microscopy, and has limited spatial resolution and sensitivity. In this communication, we develop a novel piezomagnetic force microscopy (PmFM) technique, with the imaging principle based on the detection of magnetostrictive response excited by an external magnetic field. In combination with the dual AC resonance tracking (DART) technique, the contact stiffness and energy dissipation of the samples can be simultaneously mapped along with the PmFM phase and amplitude, enabling quantitative probing of magnetic materials and structures at the nanoscale with high sensitivity and spatial resolution. PmFM has been applied to probe magnetic soft discs and cobalt ferrite thin films, demonstrating it as a powerful tool for a wide range of magnetic materials. PMID:23720016