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1

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

PubMed Central

Background Phytohormones are the key metabolites participating in the regulation of multiple functions of plant organism. Among them, jasmonates, as well as abscisic and salicylic acids are responsible for triggering and modulating plant reactions targeted against pathogens and herbivores, as well as resistance to abiotic stress (drought, UV-irradiation and mechanical wounding). These factors induce dramatic changes in phytohormone biosynthesis and transport leading to rapid local and systemic stress responses. Understanding of underlying mechanisms is of principle interest for scientists working in various areas of plant biology. However, highly sensitive, precise and high-throughput methods for quantification of these phytohormones in small samples of plant tissues are still missing. Results Here we present an LC-MS/MS method for fast and highly sensitive determination of jasmonates, abscisic and salicylic acids. A single-step sample preparation procedure based on mixed-mode solid phase extraction was efficiently combined with essential improvements in mobile phase composition yielding higher efficiency of chromatographic separation and MS-sensitivity. This strategy resulted in dramatic increase in overall sensitivity, allowing successful determination of phytohormones in small (less than 50 mg of fresh weight) tissue samples. The method was completely validated in terms of analyte recovery, sensitivity, linearity and precision. Additionally, it was cross-validated with a well-established GC-MS-based procedure and its applicability to a variety of plant species and organs was verified. Conclusion The method can be applied for the analyses of target phytohormones in small tissue samples obtained from any plant species and/or plant part relying on any commercially available (even less sensitive) tandem mass spectrometry instrumentation. PMID:23173950

2012-01-01

2

Development and validation of a highly sensitive UPLC-MS/MS method for simultaneous determination of aconitine, mesaconitine, hypaconitine, and five of their metabolites in rat blood and its application to a pharmacokinetics study of aconitine, mesaconitine, and hypaconitine.  

PubMed

A rapid, specific and sensitive method was developed for the simultaneous determination of eight Aconitum alkaloids: aconitine (AC), mesaconitine (MA), hypaconitine (HA), benzoylaconine (BAC), benzoylmesaconine (BMA), benzoylhypaconine (BHA), aconine and mesaconine in rat blood by ultra-performance liquid chromatography coupled tandem mass spectrometry (UPLC-MS/MS). The UPLC-MS/MS system coupled with an electrospray ionization (ESI) source was operated in a positive mode via multiple-reaction monitoring (MRM). Samples were treated with methanol to remove protein prior to analysis by UPLC-MS/MS. The analytes were separated with a Waters C18 column (1.7 µm, 50?×?2.1?mm) and a gradient elution using acetonitrile and 0.1% formic acid-water as the mobile phases. The linear response range was from 0.125 to 1000 nmol/L for these eight alkaloids and the correlation coefficients (r(2) values) were all higher than 0.997. The method was validated with respect to precision, accuracy, recovery, matrix effect, carryover effect and sample stability, and found to be within the acceptable limits. The developed and validated method was successfully applied to simultaneously determine the eight Aconitum alkaloids in rats blood after intravenous administration of a mixture of AC, MA and HA. PMID:22188409

Ye, Ling; Gao, Song; Feng, Qian; Liu, Wei; Yang, Zhen; Hu, Ming; Liu, Zhongqiu

2012-06-01

3

Development of a highly sensitive and selective UPLC/MS/MS method for the simultaneous determination of testosterone and 5alpha-dihydrotestosterone in human serum to support testosterone replacement therapy for hypogonadism.  

PubMed

A highly sensitive and selective quantitative method to accurately determine testosterone (Te) and 5alpha-dihydrotestosterone (DHT) in human serum is crucial to the success of Te replacement therapy for hypogonadism. To this end we have developed and validated a semi-automated and relatively high-throughput method in a 96-well plate format using ultra-performance liquid chromatography coupled with tandem mass spectrometry (UPLC/MS/MS) for the simultaneous determination of Te and DHT in human serum. Te and DHT along with the internal standards [(2)H(3)]-Te and [(2)H(3)]-DHT were extracted from 300 microL of human serum by liquid-liquid extraction using methyl tertiary-butyl ether (MTBE), followed by derivatization with 2,3-pyridinedicarboxylic anhydride and solid-phase extraction for sample clean up. A novel chemical derivatization approach using 2,3-pyridinedicarboxylic anhydride was employed to achieve the MS sensitivity and selectivity required for DHT. Baseline separation of Te and DHT derivatives from endogenous steroid derivatives was achieved using UPLC technology on a C18 stationary-phase column with 1.7 microm particle size. The validity of using double charcoal-stripped female human serum as surrogate matrix for preparation of calibration standards was demonstrated through standard addition experiments. The method was validated over the concentration ranges of 0.2-40 ng/mL for Te and 0.01-2 ng/mL for DHT. The validation and study sample analysis results show that the method is rugged, precise, accurate, and well suited to support pharmacokinetic studies where approximately 300 samples can be extracted and analyzed in 1 day. PMID:18329061

Licea-Perez, Hermes; Wang, Sherry; Szapacs, Matthew E; Yang, Eric

2008-07-01

4

Development and validation of a rapid and sensitive UPLC-MS/MS method for determination of total docetaxel from a lipid microsphere formulation in human plasma.  

PubMed

Docetaxel lipid microsphere (DT-LM), an intravenous lipid emulsion for docetaxel without Tween 80, has demonstrated significant advantage over other conventional docetaxel formulations with respect to keeping sustained release, reducing irritation or toxicity of drug, sterile for intravenous injection and presenting targeting. A rapid, sensitive and reproducible ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for determination of total docetaxel from a lipid microsphere formulation in human plasma using paclitaxel as internal standard (IS) has been developed and validated. The analytes and IS were extracted from plasma by simple liquid-liquid extraction and separated on ACQUITY UPLC BEH C18 column at a flow rate of 0.3 ml/min using gradient elution mode. The total analytical time was only 2.5 min. Detection and quantitation were performed by electrospray ionization (ESI) in the positive ionization mode by multiple reaction monitoring (MRM) of the transitions at m/z 808.3?527.1 for docetaxel and 854.0?285.9 for IS. The assay was linear over the concentration range of 2-5000 ng/ml (r(2)>0.99) with the lower limit of quantification (LLOQ) of 2 ng/ml. The intra- and inter-day precision in terms of relative standard deviation (RSD%) was within 9% and accuracy in terms of relative error (RE%) was within 12%. The rapid, sensitive and reproducible UPLC-MS/MS method is now used to support clinical pharmacologic studies with DT-LM injection in patients with advanced cancer. PMID:23567294

Du, Ping; Li, Ning; Wang, Hongyu; Yang, Sheng; Song, Yuanyuan; Han, Xiaohong; Shi, Yuankai

2013-05-01

5

A sensitive analytical procedure for monitoring acrylamide in environmental water samples by offline SPE-UPLC/MS/MS.  

PubMed

The presence of acrylamide in natural systems is of concern from both environmental and health points of view. We developed an accurate and robust analytical procedure (offline solid phase extraction combined with UPLC/MS/MS) with a limit of quantification (20 ng L(-1)) compatible with toxicity threshold values. The optimized (considering the nature of extraction phases, sampling volumes, and solvent of elution) solid phase extraction (SPE) was validated according to ISO Standard ISO/IEC 17025 on groundwater, surface water, and industrial process water samples. Acrylamide is highly polar, which induces a high variability during the SPE step, therefore requiring the use of C(13)-labeled acrylamide as an internal standard to guarantee the accuracy and robustness of the method (uncertainty about 25 % (k?=?2) at limit of quantification level). The specificity of the method and the stability of acrylamide were studied for these environmental media, and it was shown that the method is suitable for measuring acrylamide in environmental studies. PMID:25471720

Togola, Anne; Coureau, Charlotte; Guezennec, Anne-Gwenaëlle; Touzé, Solène

2014-12-01

6

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

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. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24828525

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

2015-01-01

7

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

PubMed

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

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

2015-03-01

8

A simple and sensitive assay for eflornithine quantification in rat brain using pre-column derivatization and UPLC-MS/MS detection.  

PubMed

Eflornithine (?-difluoromethylornithine) has been used to treat second-stage (or meningoencephalitic-stage) human African trypanosomiasis and currently is under clinical development for cancer prevention. In this study, a new ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS)-based assay was developed and validated for the quantification of eflornithine in rat brain. To improve chromatographic retention and MS detection, eflornithine was derivatized with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate for 5?min at room temperature prior to injection. Derivatized eflornithine was separated on a reverse-phase C18 UPLC column with a 6-min gradient; elution occurred at approximately 1.5?min. Prior to derivatization, eflornithine was reproducibly extracted from rat brain homogenate by methanol protein precipitation (~70% recovery). Derivatized eflornithine was stable in the autosampler (6?°C) for at least 24?h. This new assay had acceptable intra- and interday accuracy and precision over a wide dynamic range (5000-fold) and excellent sensitivity with a lower limit of quantification of 0.1?µm (18?ng/mL) using only 10??L of rat brain homogenate. The validated eflornithine assay was applied successfully to determine eflornithine distribution in different regions of rat brain in an in situ rat brain perfusion study. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25365958

Yang, Sihyung; Peng, Kuan-Wei; Wang, Michael Zhuo

2014-11-01

9

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

PubMed

In this study, a simple, rapid and sensitive ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method is described for determination of domperidone in human plasma samples using oxcarbazepine as the internal standard (IS). Sample preparation was accomplished through protein precipitation with methanol, and chromatographic separation was performed on an Acquity BEH C18 column (2.1?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

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

2014-06-01

10

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

PubMed

Overexpression of P-glycoprotein leads to tumor multidrug resistance (MDR). HZ08, a novel tetrahydro-isoquinoline derivate, was discovered to inhibit the MDR in the cancer cell lines of MCF-7/ADM, K562/ADM and KBV in our previous studies. A rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometric method (UPLC-MS/MS) was developed and validated for determination of HZ08 in rat plasma and tissues after intravenous administration of HZ08 liposome injection at different doses. The analytes were extracted from plasma and tissues using protein precipitation by acetonitrile with clotrimazole as internal standard. The chromatographic separation was performed on a Thermo BDS HYPERSIL C18 column (100mm×4.6mm, 2.4?m) at a flow rate of 0.7ml/min using 0.2% ammonium acetate solution (containing 0.1% formic acid) and methanol as mobile phase. The total run time was 4min. The tandem mass detection was applied with electrospray ionization in positive ion selected reaction monitoring mode. The ion transitions monitored were m/z 523.5 to 342.3 for HZ08 and 277.1 to 165.1 for the internal standard, respectively. The calibration curves obtained were linear in different matrices, and the lower limit of quantification (LLOQ) achieved was 1ng/ml for rat plasma and 0.25ng/ml for rat tissues, respectively. The RSDs for intra- and inter-day precision were less than 15%. Extraction recovery, matrix effect and stability were satisfactory in rat plasma and tissues. The developed method was successfully applied to a pharmacokinetic study of HZ08 liposome injection following intravenous administration of 1, 3, 10mg/kg to Sprague-Dawley rats. The data profiles revealed that HZ08 had linear pharmacokinetic properties at the tested doses, and was rapidly distributed into the systemic circulation with wide distribution throughout the body followed by a rapid elimination phase. The major distribution tissues of HZ08 in rats were lung, spleen and liver. These results provided constructive contribution to support the clinical evaluation. PMID:25305722

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

2015-01-01

11

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

PubMed

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

Zhao, Ying-Yong; Lin, Rui-Chao

2014-05-25

12

Use of a sensitive and robust UPLC-MS/MS method to determine the gender-dependent pharmacokinetics in rats of emodin and its glucuronide  

PubMed Central

The purpose of this research was to set up a sensitive and consistent UPLC-UV and UPLCMS/MS method to analyze emodin and its glucuronidated metabolite, and to determine how gender differences affect its pharmacokinetic behaviors. In addition, a breast cancer resistance protein inhibitor dipyridamole was used to test how significant the absolute oral biovailabilty of emodin or its glucuronide is increased. A sensitive and fast UPLC-MS/MS method was successfully applied to determine emodin and its metabolite in male and female SD rat plasma. The absolute oral bioavailability of emodin was extremely low whether in male rats (7.5%) and female rats (5%). Following a single intravenous injection of 4 mg/kg emodin, the emodin plasma concentration-time data fit for a good two-compartment model either in male or female SD rats. The t1/2? were 13.26±6.28min (male rats) and 13.52±7.28min (female rats). The t1/2? were 187.38±0.16min (male rats) and 118.50±83.09min (female rats). Emodin showed significant gender differences in i.v. PK profiles with higher AUC values in male (422.71 ± 163.40 mg*?g/ml) than female (282.52 ± 98.42 mg*?g/ml) SD rats (n=6). Emodin glucuronide was suggested a good fit for single compartmental model for the plasma emodin metabolite concentrations. The t1/2Ke were 167.40±50.91min(male rats) and 251.31±114.20min (female rats), the area under the curve (AUC0-?, i.v.) were 2210.02 ± 950.09 mg*?g/ml and 1054.42 ± 290.31 mg*?g/ml (female rats)(n=6). There was no good fit for any PK compartmental model for the plasma concentration-time data for single dose oral administration of emodin (8mg/kg) and its metabolite. Analyzing the oral PK data using non-compartmental model, Cmax, Tmax and AUC0-?, p.o. of emodin in male rats were: 0.31±0.094 were ?g/ml, 18.00±6.71min and 65.76±34.77 mg*?g/ml respectively; whereas Cmax, Tmax and AUC0-?, p.o. of emodin in female rats were: 0.039±0.011 ?g/ml, 18.75±7.51min and 33.82±4.09 mg*?g/ml respectively. The parameters of emodin glucuronide were significant different with emodin, the Cmax, Tmax and AUC0-?, p.o of emodin glucuronide in male rats were 6.69±1.06 ?g/ml, 240min and 2261.89±655.87 mg*?g/ml respectively, in female rats, the Cmax, Tmax and AUC0-?, p.o. were 1.81±0.58 ?g/ml, 60min and 458.50±373.29 mg*?g/ml respectively. The absolute bioavailability of emodin glucuronide was 60% (male rats) and 15% (female rats). The absolute bioavailability of emodin was no significant changed (7.3%) in male rats by using dipyridamole, the bioavailability of metabolite of emodin was significant declined to 14.6%. PMID:21195574

Liu, Wei; Gao, Song; Zheng, Zhijie; Liu, Xi; Ye, Ling; Yang, Zhen; Hu, Ming; Liu, Zhongqiu

2014-01-01

13

A novel UPLC-MS/MS method for sensitive quantitation of boldine in plasma, a potential anti-inflammatory agent: application to a pharmacokinetic study in rats.  

PubMed

Boldine is a potential anti-inflammatory agent found in several different plants. Published bioanalytical methods using HPLC with ultraviolet and fluorescent detection lacked enough sensitivity and required tedious sample preparation procedures. Herein, we describe the development of a novel ultra-high performance LC with MS/MS for determination of boldine in plasma. Boldine in plasma was recovered by liquid-liquid extraction using 1?mL of methyl tert-butyl ether. Chromatographic separation was performed on a C18 column at 45°C, with a gradient elution consisting of acetonitrile and water containing 0.1% (v/v) formic acid at a flow rate of 0.3?mL/min. The detection was performed on an electrospray triple-quadrupole MS/MS by positive ion multiple reaction monitoring mode. Good linearity (r(2) ?>?0.9926) was achieved in a concentration range of 2.555-2555?ng/mL with a lower limit of quantification of 2.555?ng/mL for boldine. The intra- and inter-day precisions of the assay were 1.2-6.0 and 1.8-7.4% relative standard deviation with an accuracy of -6.0-8.0% relative error. This newly developed method was successfully applied to a single low-dose pharmacokinetic study in rats and was demonstrated to be simpler and more sensitive than the published methods, allowing boldine quantification in reduced plasma volume. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25065486

Zeng, Rong-Jie; Li, Yu; Chen, Jian-Zhong; Chou, Gui-Xin; Gao, Yu; Shao, Jing-Wei; Jia, Lee; Wu, Sheng-Dong; Wu, Shui-Sheng

2015-03-01

14

Development and validation of a fast and sensitive UPLC-MS/MS method for the quantification of six probe metabolites for the in vitro determination of cytochrome P450 activity.  

PubMed

A fast and sensitive UPLC-MS/MS method was developed and validated for the simultaneous quantification of six probe metabolites for the in vitro cytochrome P450 activity determination in hepatic microsomes from patients with hepatic impairment. The metabolites acetaminophen (CYP1A2), 4'-hydroxy-mephenytoin (CYP2C19), 4-hydroxy-tolbutamide (CYP2C9), dextrorphan (CYP2D6), 6-hydroxy-chlorzoxazone (CYP2E1) and 1-hydroxy-midazolam (CYP3A4), together with the internal standard chlorpropamide, were separated on a Waters Acquity UPLC BEH C18 column (50 mm × 2.1mm, 1.7 ?m particle size) with VanGuard pre-column (5 mm × 2.1mm, 1.7 ?m particle size). A short gradient elution (total run time of 5.25 min), using water with 0.1% formic acid (eluent A) and acetonitrile with 0.1% formic acid (eluent B) at a flow rate of 400 ?l/min, was used. The metabolites were detected with a triple quadrupole mass spectrometer in the multiple reaction monitoring mode. Two runs, one in the positive ionization mode and one in the negative mode, were necessary for the detection of all metabolites. The method was selective and showed good accuracy (84.59-109.83%) and between-day (RSD%<5.13%) and within-day (RSD%<9.60%) precision. The LOQ was in full accordance with the intended application, and no relative matrix effects were observed. Also, the sample incubation extracts were stable after three freeze-thaw cycles. The usability of the method was demonstrated by the incubation of pediatric microsomes with subsequent quantification of the formed metabolites and CYP activity calculation. PMID:22284482

De Bock, Lies; Boussery, Koen; Colin, Pieter; De Smet, Julie; T'jollyn, Huybrecht; Van Bocxlaer, Jan

2012-01-30

15

Simultaneous determination of antidementia drugs in human plasma: procedure transfer from HPLC-MS to UPLC-MS/MS.  

PubMed

A previously developed high performance liquid chromatography mass spectrometry (HPLC-MS) procedure for the simultaneous determination of antidementia drugs, including donepezil, galantamine, memantine, rivastigmine and its metabolite NAP 226-90, was transferred to an ultra performance liquid chromatography system coupled to a tandem mass spectrometer (UPLC-MS/MS). The drugs and their internal standards ([(2)H(7)]-donepezil, [(13)C,(2)H(3)]-galantamine, [(13)C(2),(2)H(6)]-memantine, [(2)H(6)]-rivastigmine) were extracted from 250 ?L human plasma by protein precipitation with acetonitrile. Chromatographic separation was achieved on a reverse phase column (BEH C18 2.1 mm × 50 mm; 1.7 ?m) with a gradient elution of an ammonium acetate buffer at pH 9.3 and acetonitrile at a flow rate of 0.4 mL/min and an overall run time of 4.5 min. The analytes were detected on a tandem quadrupole mass spectrometer operated in positive electrospray ionization mode, and quantification was performed using multiple reaction monitoring. The method was validated according to the recommendations of international guidelines over a calibration range of 1-300 ng/mL for donepezil, galantamine and memantine, and 0.2-50 ng/mL for rivastimgine and NAP 226-90. The trueness (86-108%), repeatability (0.8-8.3%), intermediate precision (2.3-10.9%) and selectivity of the method were found to be satisfactory. Matrix effects variability was inferior to 15% for the analytes and inferior to 5% after correction by internal standards. A method comparison was performed with patients' samples showing similar results between the HPLC-MS and UPLC-MS/MS procedures. Thus, this validated UPLC-MS/MS method allows to reduce the required amount of plasma, to use a simplified sample preparation, and to obtain a higher sensitivity and specificity with a much shortened run-time. PMID:22410501

Noetzli, Muriel; Ansermot, Nicolas; Dobrinas, Maria; Eap, Chin B

2012-05-01

16

Depletion of urinary zilpaterol residues in horses as measured by ELISA and UPLC-MS/MS.  

PubMed

Three horses were dosed with dietary zilpaterol and the urine concentrations measured from withdrawal day 0 to withdrawal day 21. The analyses were carried out using both enzyme-linked immunosorbent assay (ELISA) and an ultraperformance liquid chromatography with triple-quadrupole-tandem mass spectrometric detection (UPLC-MS/MS). The UPLC-MS/MS method was developed to provide rapid analysis with positive analyte identification by following three product ions and computing the two independent ion ratios. When urinary zilpaterol concentrations were between 0.2 and 2 ng/mL, the ELISA had interday recoveries of 114-120% with coefficients of variation (CV) of <22%; intraday recoveries were 79-111% with CVs of <13%. For urinary zilpaterol concentrations of 0.4-40 ng/mL the UPLC-MS/MS method had interday recoveries of 94-104% with CVs of <8%; intraday recoveries were 97-102% with CVs of < or = 7.5%. Correlation analysis demonstrated that the ELISA and UPLC-MS/MS methods returned essentially the same results, especially at urinary zilpaterol concentrations below 2000 ng/mL. Urinary excretion peaked rapidly after dosing between 5300 and 10800 ng/mL (UPLC-MS/MS) or between 5900 and 17900 ng/mL (ELISA) for the different horses, much higher than observed in other species. Urinary zilpaterol concentrations declined rapidly to below 3000 ng/mL within 24 h of study day 1. After about 5 days, zilpaterol elimination slowed markedly, taking nearly 10 days for an order of magnitude decrease. The analytical methods were able to detect zilpaterol in the urine even at withdrawal day 21, demonstrating the sensitivity of each analytical method and the slow rate of zilpaterol depuration from horses. PMID:20218607

Shelver, Weilin L; Thorson, Jennifer F; Hammer, Carolyn J; Smith, David J

2010-04-14

17

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

PubMed

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

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

2013-06-10

18

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

PubMed

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

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

2015-02-15

19

Quantification of tricyclic antidepressants using UPLC-MS/MS.  

PubMed

Depression is a psychiatric condition that affects about 120 million people worldwide and can interfere with independence and productivity in essentially all aspects of daily life. Depression is also associated with risk of self-harm, and ultimately suicide. Antidepressant medications are widely used to treat symptoms of depression. While there are several classes of antidepressants, therapeutic drug management (TDM) is most common for the tricyclic antidepressants (TCAs). TDM of TCAs is important due to wide inter-individual variability in pharmacokinetics, production of active metabolites, and a high risk of drug-drug interactions. In addition, TDM of some TCAs can be used to optimize dose, wherein concentration relationships are recognized for both therapeutic response and potentially life-threatening toxicity. In many clinical scenarios, TDM of TCAs is accomplished by currently available point of care or automated immunoassays that provide a "total" TCA concentration. However, these assays may not be adequately specific to meet the needs of all clinical scenarios, and hence, chromatographic separation and quantification of individual TCA parent drugs and active metabolites that may contribute to the "total" TCA concentration is sometimes required. This chapter describes an analytical method designed to detect and/or quantify clinically significant concentrations of nine TCAs (amitriptyline, nortriptyline, imipramine, desipramine, doxepin, nordoxepin, protriptyline, clomipramine, and norclomipramine) in serum or plasma, using ultra pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The sample preparation employs a rapid protein precipitation with 50:50 MeOH:acetonitrile, high speed centrifugation, and injection of 5 ?L of supernatant onto the instrument, with a 5 min run-time. PMID:22767118

Johnson-Davis, Kamisha L; Juenke, Joetta M; Davis, Rebecka; McMillin, Gwendolyn A

2012-01-01

20

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

PubMed Central

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

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

21

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

Microsoft Academic Search

Animal pharmacokinetic and tissue distribution assays of antiretroviral therapeutic drugs require accurate drug quantification in biological fluids and tissues. Here we report a simple, rapid, and sensitive ultra performance liquid chromatography–tandem mass spectrometry (UPLC–MS\\/MS) method for quantification of commonly used antiretroviral drugs ritonavir (RTV), indinavir (IDV), atazanavir (ATV), and efavirenz (EFV) in mouse serum and tissues (liver, kidney, lung, and

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

2011-01-01

22

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

PubMed

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

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

2013-04-01

23

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

PubMed

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

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

2014-02-01

24

Rapid quantitative analysis of clarithromycin in rat plasma by UPLC-MS/MS after intravenous injection of the clarithromycin-loaded ultrafine PLGA nanoparticles.  

PubMed

Nanoparticles were designed to encapsulate drugs to alter their pharmacological behaviors, therefore, it is very essential to monitor the pharmacokinetic profile of drug encapsulated in nanoparticles in order to clarify and predict their efficacy and side effects. In this paper, we reported a simple, rapid ?-elution 96-well solid phase extraction (?SPE) method combining with ultra high performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for determination of nanoformulated drug in rat plasma. This method presented satisfactory results in terms of sensitivity, precision, accuracy, and recovery, for the first time, of quantitatively analyzing clarithromycin (CLA) in rat plasma after intravenous administration CLA-loaded ultrafine PLGA nanoparticles for pharmacokinetic study. This method has been proved to be fast, reliable and reproducible to accurately analyze drug encapsulated in polymeric nanoparticles sample for a pharmacokinetic study. PMID:22483396

Wang, Yu-Jing; Wu, Yi-Ting; Lin, Jia-Yi; Chu, Chih-Hung; Huang, Hsin-Ying; Wang, Yu-Chao; Chen, Jen-Kun; Yang, Chung-Shi

2012-05-01

25

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

PubMed

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

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

2015-02-01

26

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

PubMed

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

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

2013-05-15

27

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

PubMed Central

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

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

2014-01-01

28

Coumarin and furanocoumarin quantitation in citrus peel via ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS).  

PubMed

Coumarins and furanocoumarins are secondary metabolites commonly found in citrus plants. These molecules are allelochemical compounds in plants that have controversial effects on humans, such as phototoxicity and the commonly described interactions with drugs, referred to as the "grapefruit juice effect". Thus, it is important to develop a reliable method to identify and quantitate the coumarins and furanocoumarins in citrus extracts. For this purpose, we herein describe an ultraperformance liquid chromatography coupled with mass spectrometry (UPLC-MS)-based method. We first developed a rapid UPLC method (20 min) to separate the isomers of each furanocoumarin. A subsequent single ion monitoring MS detection method was performed to distinguish between the molecules, which were possibly coeluting but had different molecular weights. The method was successfully used to separate and quantitate 6 coumarins and 21 furanocoumarins in variable amounts within peel extracts (flavedo and albedo) of 6 varieties of Citrus (sweet orange, lemon, grapefruit, bergamot, pummelo, and clementine). This method combines high selectivity and sensitivity in a rapid analysis and is useful for fingerprinting Citrus species via their coumarin and furanocoumarin contents. PMID:24117278

Dugrand, Audray; Olry, Alexandre; Duval, Thibault; Hehn, Alain; Froelicher, Yann; Bourgaud, Frédéric

2013-11-13

29

Pharmacokinetics of di-isononyl phthalate in freely moving rats by UPLC-MS/MS.  

PubMed

Di-isononyl phthalate (DINP) is a general-purpose plasticizer for polyvinyl chloride. However, this industrial chemical plasticizer used as a clouding agent has recently contaminated food and beverages that had been inspected by Taiwan Food and Drug Administration. This study develops a sensitive and specific method combining ultra-performance liquid chromatography with electrospray ionization tandem mass spectrometry (UPLC-MS/MS) to investigate the pharmacokinetics of DINP in freely moving rats. Multiple reaction monitoring (MRM) was used to monitor the transition of the protonated molecule m/z of 419 [M+H](+) to the product ion 149 for DINP. The analyte was analyzed by UPLC-MS/MS with C18 column (100×2.1mm, 1.7 ?m) which was equilibrated and eluted with an isocratic mixture of acetonitrile-ammonium acetate water solution (90:10, v/v) at a flow rate of 0.3 mL/min. Linear calibration curves were obtained for DINP concentration ranges of 0.05-2.5 ?g/mL in plasma and feces. The feces were homogenized mechanically using 50% acetonitrile as the medium. The pharmacokinetic curve demonstrates that the disposition of DINP in rat plasma was fitted well by the two-compartment model after DINP administration (10 mg/kg, i.v.). The elimination half-life of DINP was 364±146 min and 150±58 min for intravenous (10 mg/kg) and oral (100 mg/kg) administration, respectively. The pharmacokinetic data indicate that the oral bioavailability of DINP in freely moving rats was about 1.19%. The total DINP excretion up to 48 h was 13.64±3.99% in feces. PMID:23618960

Hou, Mei-Ling; Chang, Li-Wen; Chiang, Chang-Jung; Tsuang, Yang-Hwei; Lin, Chi-Hung; Tsai, Tung-Hu

2013-06-25

30

A rapid and sensitive UPLC-MS/MS method for quantification of two caffeoylquinic acids and four main active components in rat plasma after an intravenous administration of Qingkailing injection and its application to a pharmacokinetic study.  

PubMed

Qingkailing (QKL) injection, a modified modern Chinese medicine preparation, is widely used in the clinic for its significant antipyretic and anti-inflammatory effects, but its serious adverse drug reactions have attracted more and more attention. Series of caffeoylquinic acids in QKL are widely suspected to be the allergens responsible for these adverse drug reactions. Therefore, pharmacokinetic studies of the caffeoylquinic acids are needed. In this paper, a simple, rapid and sensitive ultra-performance liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of chlorogenic acid, neochlorogenic acid, baicalin, geniposide, cholic acid and hyodeoxycholic acid in rat plasma. Chromatographic separation was achieved on a BEH C18 column by a gradient elution at a flow rate of 0.40?mL/min in only 6.0?min. All analytes were monitored by multiple reaction monitoring mode with negative electrospray ionization. The calibration curves of these analytes were all linear (r?>?0.9978) over wide concentration ranges. The intra- and inter- day precisions (relative standard deviations) were within 14.3% and accuracy (relative error) ranged from -6.8 to 4.8%. The mean recoveries ranged from 74.5 to 105.6%. This validated method was successfully applied to the pharmacokinetic study of the six analytes in rats following an intravenous administration of QKL injection. PMID:24185835

Peng, Long; Gao, Xiaoyan; Song, Yuelin; Zhao, Longshan; Guo, Mingxing; Su, Jiankun; Zhang, Li; Liu, Haiyu

2014-05-01

31

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

PubMed Central

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

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

2014-01-01

32

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

PubMed Central

Cephapirin, a cephalosporin antibiotic, is used by the majority of dairy farms in the US. Fecal and urinary excretion of cephapirin could introduce this compound into the environment when manure is land applied as fertilizer, and may cause development of bacterial resistance to antibiotics critical for human health. The environmental loading of cephapirin by the livestock industry remains un-assessed, largely due to a lack of appropriate analytical methods. Therefore, this study aimed to develop and validate a cephapirin quantification method to capture the temporal pattern of cephapirin excretion in dairy cows following intramammary infusion. The method includes an extraction with phosphate buffer and methanol, solid-phase extraction (SPE) clean-up, and quantification using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The LOQ values of the developed method were 4.02 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

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

2014-01-01

33

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

PubMed Central

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

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

2011-01-01

34

Determination and pharmacokinetic study of pirfenidone in rat plasma by UPLC-MS/MS.  

PubMed

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of pirfenidone in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2mL of acetonitrile to a 0.1mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 3.0min and the elution of pirfenidone was at 1.39min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 186.2?92.1 for pirfenidone and m/z 237.1?194.2 for carbamazepine (IS), respectively. The calibration curve was linear over the range of 5-2000ng/mL with a lower limit of quantitation (LLOQ) of 5ng/mL. Mean recovery of pirfenidone in plasma was in the range of 80.4-84.3%. Intra-day and inter-day precision were both <12.1%. This method was successfully applied in pharmacokinetic study after oral administration of 10.0mg/kg pirfenidone in rats. PMID:25596380

Sun, Wei; Jiang, Zhe-Li; Zhou, Lei; Chen, Rui-Min; Wang, Zhe; Li, Wan-Shu; Jiang, Shuo-Min; Hu, Guo-Xin; Chen, Rui-Jie

2015-02-15

35

Determination of cefaclor by UPLC-MS-MS for a Chinese pharmacokinetic study.  

PubMed

A novel method has been developed for the determination of cefaclor in human plasma by ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS-MS). The plasma was treated by a single step of protein precipitation with acetonitrile. The chromatographic separation was performed on a Waters Acquity UPLC BEH C18 (2.1 × 100 mm, 1.7 µm) with a gradient mobile phase consisting of 0.1% formic acid and acetonitrile at a flow rate of 0.4 mL/min. The analyses were conducted by multiple reaction monitoring using the precursor-to-product combinations of m/z 367.5 ? 173.8 (cefaclor) and m/z 454.1 ? 160.3 (internal standard). Validation results indicated that the lower limit of quantification was 2 ng/mL and the assay exhibited a linear range of 2-10,000 ng/mL. Quality control samples (5, 200 and 5,000 ng/mL) in five replicates from three different runs of analysis demonstrated an intra-assay precision (relative standard deviation) of 3.7-10.7%, an inter-assay precision of 5.8-8.9%, and an overall accuracy of < 15%. A sensitive and specific method for quantifying cefaclor in human plasma has been devised and successfully applied to a pharmacokinetic study. PMID:23839802

Huang, Chenrong; Wang, Wei; Miao, Liyan

2014-08-01

36

Determination of cephalomannine in rat plasma by gradient elution UPLC-MS/MS method.  

PubMed

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of cephalomannine in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of perchloric acid-methanol (1:9, v/v) to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 2.0 min and the elution of cephalomannine was at 1.60 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 832.8?264.1 for cephalomannine and m/z 812.6?286.0 for 10-DAT (internal standard), respectively. The calibration curve was linear over the range of 10-2,000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. Mean recovery of cephalomannine in plasma was in the range of 80.9-85.3%. Intra-day and inter-day precision were both <11.2%. This method was successfully applied in pharmacokinetic study after intravenous administration of 5.0mg/kg cephalomannine in rats. PMID:24929960

Wang, Xin-Shuai; Sun, Jia-Chun; Yang, Rui-Na; Ren, Jing; Liang, Shuo; Sun, Ming; Wang, Ying-Fei; Gao, She-Gan

2014-07-15

37

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

PubMed

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

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

2014-06-01

38

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...

39

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...

40

A UPLC-MS/MS Method for Therapeutic Drug Monitoring of Etonogestrel  

PubMed Central

Introduction Etonogestrel is a progestin used in the contraceptive vaginal ring NuvaRing and the subdermal implant Implanon. A sensitive method for measuring etonogestrel is useful for further investigating the progestin’s pharmacokinetics with these alternative contraceptive formulations as well as generating important information about possible continued efficacy or potential failure to remove the subdermal implant. Methods Standards and serum samples were spiked with D8 progesterone (internal standard) and subsequently extracted with dichloromethane, dried, and reconstituted in 25% methanol with formic acid. Etonogestrel was analyzed by positive electrospray ionization in multiple reaction monitoring mode with a run time of 5.5 minutes using a C18 BEH column. The mobile phase was a gradient of water:acetonitrile, with 0.1% formic acid. The method was applied successfully to study the pharmacokinetics of etonogestrel during vaginal ring use. The method was also used in routine patient care to assess etonogestrel levels. Results The method is linear from 50pg/ml to 2000pg/ml. The limit of detection and quantification (LOD and LOQ) are 25 and 50pg/ml respectively. There was no observed ionization suppression within the linear range of the assay and the average recovery was 87%. Serum etonogestrel levels of n=3 subjects were all within the linear range of the assay for a total study period of 42 days after insertion of the ring. Of n=20 patients with non-palpable subdermal implants, n=13 had etonogestrel levels > 25 pg/mL, while n=7 had levels < 25 pg/mL. Conclusions We developed a rapid, sensitive, and robust UPLC-MS/MS method for the quantification of etonogestrel in serum that is useful to study the progestin’s pharmacokinetics and inform physicians about successful implantation or potential failure to remove a subdermal device. PMID:24081205

Thomas, Tiffany; Petrie, Kelsey; Shim, Joonho; Abildskov, Kirsten M.; Westhoff, Carolyn L.; Cremers, Serge

2013-01-01

41

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

PubMed

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

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

2013-10-15

42

An UPLC-MS/MS method for the analysis of glimepiride and fluoxetine in human plasma.  

PubMed

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine glimepiride (GPD) and fluoxetine (FLU) in human plasma using diazepam as the internal standard (IS) simultaneously. The presented method used an Acquity UPLC BEH C18 column for chromatographic separation with tandem mass spectrometric detection on a QTrap5500 mass spectrometer operated in positive ESI mode. The mobile phase is a mixture of acetonitrile and 1% formic acid in water with gradient elution at a flow rate of 0.40mL/min. The GPD, FLU and IS were eluted at 1.46, 1.27 and 1.39min, respectively. The MRM transitions of m/z 491.3?126.3 and m/z 310.5?148.1 were used to quantify for GPD and FLU, respectively. The linearity of this method was found to be within the concentration range of 2.5-300ng/mL and 0.1-20ng/mL for GPD and FLU in human plasma, respectively. The intra- and inter-day precision (RSD%) were less than 10.3% and accuracy (RE%) was within ±7.3%. The matrix effect were 95.3-100.7% for GPD and FLU. GPD and FLU were sufficiently stable under all relevant analytical conditions. The method was also successfully applied to the clinical samples after a single oral dose of 2mg GLP and 40mg FLU in patients. PMID:25589252

Qiu, Xiangjun; Wang, Hong-Wei; Yuan, Ye; Wang, Ying-Fei; Sun, Ming; Huang, Xue-Sun

2015-02-01

43

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

PubMed

Bisphenol A (BPA), a widespread man-made chemical classified as an endocrine disruptor, is increasingly considered as a major cause of concern for human health. Chlorine present in drinking water may react with BPA to form chlorinated derivatives (ClxBPA), which have demonstrated a heightened level of estrogenic activity. If many epidemiological studies report that more than 90% of people have detectable BPA levels in their urine, then no such study has been undertaken regarding ClxBPA. The purpose of this work is to propose a highly sensitive and accurate analytical method adapted to large-scale biomonitoring studies aimed at assessing exposure to BPA and ClxBPA through the use of human urine. To achieve this, we have comprehensively validated a method using salting-out assisted liquid/liquid extraction (SALLE) coupled to UPLC-MS/MS and isotope dilution quantification, to measure unconjugated BPA and ClxBPA in human urine according to the accepted guidelines. Deutered BPA as well as deutered 2,2'-DCBPA was used as internal standards. The matrix calibration curve ranged from 0.05 to 1.60 ng mL(-1) and from 0.5 to 16.0 ng mL(-1) for ClxBPA and BPA respectively, and provided good linearity (r²>0.99). This method was precise (the intra- and inter-day coefficients of variation were <20% at three different concentrations: 0.05 ng mL(-1), 0.2 ng mL(-1), 0.8 ng mL(-1) and 0.5 ng mL(-1), 2 ng mL(-1), 8 ng mL(-1) for ClxBPA and BPA, respectively) and accurate (bias ranged from -13% to +12%). The limit of quantification, validated at 0.05 ng mL(-1) and 0.5 ng mL(-1) for ClxBPA and BPA respectively when using 300 µL of urine, was found to be suitable for the concentration existing in real samples. The matrix effect and the BPA cross-contamination were also investigated in this study. The analytical method developed in this study is in accordance with the requirements applicable to biomonitoring of BPA and ClxBPA in human urine. PMID:24840445

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

2014-07-01

44

Simultaneous extraction and screening of diuretics, beta-blockers, selected stimulants and steroids in human urine by HPLC-MS/MS and UPLC-MS/MS.  

PubMed

Described herein are two general screening procedures for the simultaneous determination of 49 exogenous compounds (21 diuretics, 19 beta-blockers, eight stimulants and two steroidal drugs) in human urine by high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) and ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS). Urine samples were extracted using a simple and robust solid phase extraction (SPE) method. Samples were injected onto reversed phase HPLC and UPLC columns connected to tandem mass spectrometers capable of scan-to-scan polarity switching. The methods were validated according to the ISO 17025 international standard for the validation of a qualitative method. Sixty urine samples submitted for routine analysis were tested using both methods, the results of which correlated with results obtained from previously validated procedures. Both methods proved to be useful for routine urine analysis; most notably, the use of UPLC-MS/MS demonstrated that samples can be reliably screened with significantly reduced analysis times. PMID:19837636

Murray, Gordon J; Danaceau, Jonathan P

2009-11-15

45

Systematic development of an UPLC-MS/MS method for the determination of tricyclic antidepressants in human urine.  

PubMed

Tricyclic antidepressants have been prescribed for the treatment of depression and other disorders since their discovery in the 1950s but have been replaced in recent decades by newer drugs with more favorable side effect profiles. However, for some patients and conditions, tricyclic antidepressants remain the drug of choice. A fast, sensitive, and robust UPLC-MS/MS method for the monitoring of amitriptyline, nortriptyline, imipramine, doxepin, and desipramine in human urine has been developed using a pre-defined and systematic method development approach. The method was developed using sub-2-?m particle technology, providing a state-of-the-art alternative to older methods. Total cycle time was 2.5min. Human urine samples (200?L) were prepared using an Oasis(®) WCX ?Elution solid-phase extraction plate, which provided good recovery for all analytes (>92%) and low matrix effects (absolute matrix effects <10%). Standard curves were linear over the range 0.02-250ng/mL with r(2) values>0.994. The method was evaluated against current FDA guidelines and was applied to the analysis of patient samples, including an assessment of incurred sample reanalysis (ISR). PMID:24239905

Chambers, Erin E; Woodcock, Matthew J; Wheaton, Jessalynn P; Pekol, Teresa M; Diehl, Diane M

2014-01-01

46

Quantitative determination of ketoconazole by UPLC-MS/MS in human plasma and its application to pharmacokinetic study.  

PubMed

In this study, a simple, rapid and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method is described for determination of ketoconazole (KTZ) in human plasma samples using carbamazepine as the internal standard (IS). Sample preparation was accomplished through one-step liquid-liquid extraction by ethyl acetate, and chromatographic separation was performed on an Acquity BEH C18 column (2.1?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 531.2?489.3 was used to quantify for KTZ. The linearity of this method was found to be within the concentration range of 5-15?000?ng/mL for KTZ in human plasma. Only 1.5?min was needed for an analytical run. The method herein described was superior to previous methods and was successfully applied to the pharmacokinetic study of KTZ in healthy Chinese volunteers after oral administration. PMID:24452517

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

2014-10-01

47

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

PubMed

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

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

2014-11-01

48

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

PubMed

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 2.1×100mm 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 2.32min, 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 0.1-40ng/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

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

49

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

PubMed

A sensitive and rapid ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was developed to determine voriconazole in human plasma. Sample preparation was accomplished through a simple one-step protein precipitation with methanol. Chromatographic separation was carried out on an Acquity UPLC BEH C18 column using an isocratic mobile phase system composed of acetonitrile and water containing 1% formic acid (45:55, v/v) at a flow rate of 0.50?mL/min. Mass spectrometric analysis was performed using a QTrap5500 mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 351.0???281.5 and m/z 237.1???194.2 were used to quantify voriconazole and carbamazepine (internal standard), respectively. The linearity of this method was found to be within the concentration range of 2.0-1000?ng/mL with a lower limit of quantification of 2.0?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 200?mg voriconazole to 20 Chinese healthy male volunteers. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24925071

Wang, Zhe; Huang, Cheng-Ke; Sun, Wei; Xiao, Cui; Wang, Zeng-Shou

2015-02-01

50

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

PubMed

A sensitive and rapid ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine 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

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

2014-09-15

51

Development and validation of an ultrafiltration-UPLC-MS/MS method for rapid quantification of unbound docetaxel in human plasma.  

PubMed

Docetaxel lipid microsphere (DT-LM) is a novel formulation of docetaxel without Tween-80. A sensitive, robust and reproducible ultrafiltration (UF) followed by UPLC-MS/MS method was developed and validated for the quantification of unbound docetaxel in human plasma using paclitaxel as IS. Ultrafiltrate samples were chromatographed on Acquity UPLC BEH C18 column (50 mm × 2.1 mm, 1.7 ?m). The mobile phase was a mixture of 10mM ammonium formate in water containing 0.2% formic acid (A) and acetonitrile containing 0.2% formic acid (B). The volume of plasma utilized was only 450 ?L. The calibration curve was linear over the range of 0.2-200 ng/mL, with LLOQ of 0.2 ng/mL. The method was shown to be reliable and reproducible with intra- and inter-day precision and accuracy <±15%, and extraction recovery of 98.1-104.8%. Docetaxel was stable during stability studies, e.g., short term, post-preparation and freeze-thaw cycles. The validated method was utilized to support the pharmacological study of DT-LM in patients with advanced cancer. PMID:25063925

Du, Ping; Han, Xiaohong; Li, Ning; Wang, Hongyu; Yang, Sheng; Song, Yuanyuan; Shi, Yuankai

2014-09-15

52

UPLC-MS/MS method for determination of avicularin in rat plasma and its application to a pharmacokinetic study.  

PubMed

A rapid, sensitive and selective ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) was developed and validated for the determination and pharmacokinetic investigation of avicularin in rat plasma. Sample preparation was accomplished through a simple one-step deproteinization procedure with 0.2 mL of acetonitrile-methanol (9:1, v/v) to a 0.1 mL plasma sample. Plasma samples were separated by UPLC on an Acquity UPLC BEH C18 column using a mobile phase consisting of acetonitrile-0.1% formic acid in water with gradient elution. The total run time was 1.60 min and the elution of avicularin was at 1.20 min. The detection was performed on a triple quadrupole tandem mass spectrometer in the multiple reaction-monitoring (MRM) mode using the respective transitions m/z 434.1?301.3 for avicularin and m/z 237.2?194.3 for carbamazepine (IS), respectively. The calibration curve was linear over the range of 10-3000 ng/mL with a lower limit of quantitation (LLOQ) of 10 ng/mL. Mean recovery of avicularin in plasma was in the range of 84.2-89.5%. Intra-day and inter-day precision were both <12%. This method was successfully applied in pharmacokinetic study after intravenous administration of 5.0mg/kg avicularin in rats. PMID:25010713

Zhang, Wei-Min; Li, Rui-Fang; Sun, Ming; Hu, Da-Ming; Qiu, Jian-Fei; Yan, Yun-Hao

2014-08-15

53

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

PubMed

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 2.5min. Chromatographic separation was performed on a Waters Acquity UPLC system using a BEH C18 column (1.7?m, 100mm×2.1mm) applying a binary gradient elution of water and methanol both containing 0.1% formic acid and 2mmol/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 100mg/L for amoxicillin and cefuroxime, between 0.5 and 80mg/L for meropenem and ceftazidime, and between 1 and 150mg/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

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

2015-01-26

54

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

PubMed Central

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

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

2013-01-01

55

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

PubMed

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

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

2015-03-01

56

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

PubMed

This paper presents the development of a rapid method with ultraperformance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) for the qualitative and quantitative analyses of plant proanthocyanidins directly from crude plant extracts. The method utilizes a range of cone voltages to achieve the depolymerization step in the ion source of both smaller oligomers and larger polymers. The formed depolymerization products are further fragmented in the collision cell to enable their selective detection. This UPLC-MS/MS method is able to separately quantitate the terminal and extension units of the most common proanthocyanidin subclasses, that is, procyanidins and prodelphinidins. The resulting data enable (1) quantitation of the total proanthocyanidin content, (2) quantitation of total procyanidins and prodelphinidins including the procyanidin/prodelphinidin ratio, (3) estimation of the mean degree of polymerization for the oligomers and polymers, and (4) estimation of how the different procyanidin and prodelphinidin types are distributed along the chromatographic hump typically produced by large proanthocyanidins. All of this is achieved within the 10 min period of analysis, which makes the presented method a significant addition to the chemistry tools currently available for the qualitative and quantitative analyses of complex proanthocyanidin mixtures from plant extracts. PMID:24665824

Engström, Marica T; Pälijärvi, Maija; Fryganas, Christos; Grabber, John H; Mueller-Harvey, Irene; Salminen, Juha-Pekka

2014-04-16

57

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

PubMed Central

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

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

2014-01-01

58

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

PubMed

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

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

2014-07-15

59

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

PubMed Central

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

2013-01-01

60

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

PubMed

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

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

2014-10-31

61

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

PubMed

The generation of natural product libraries containing column fractions, each with only a few small molecules, using a high-throughput, automated fractionation system, has made it possible to implement an improved dereplication strategy for selection and prioritization of leads in a natural product discovery program. Analysis of databased UPLC-MS-ELSD-PDA information of three leads from a biological screen employing the ependymoma cell line EphB2-EPD generated details on the possible structures of active compounds present. The procedure allows the rapid identification of known compounds and guides the isolation of unknown compounds of interest. Three previously known flavanone-type compounds, homoeriodictyol (1), hesperetin (2), and sterubin (3), were identified in a selected fraction derived from the leaves of Eriodictyon angustifolium. The lignan compound deoxypodophyllotoxin (8) was confirmed to be an active constituent in two lead fractions derived from the bark and leaves of Thuja occidentalis. In addition, two new but inactive labdane-type diterpenoids with an uncommon triol side chain were also identified as coexisting with deoxypodophyllotoxin in a lead fraction from the bark of T. occidentalis. Both diterpenoids were isolated in acetylated form, and their structures were determined as 14S,15-diacetoxy-13R-hydroxylabd-8(17)-en-19-oic acid (9) and 14R,15-diacetoxy-13S-hydroxylabd-8(17)-en-19-oic acid (10), respectively, by spectroscopic data interpretation and X-ray crystallography. This work demonstrates that a UPLC-MS-ELSD-PDA database produced during fractionation may be used as a powerful dereplication tool to facilitate compound identification from chromatographically tractable small-molecule natural product libraries. PMID:24617915

Yang, Jin; Liang, Qian; Wang, Mei; Jeffries, Cynthia; Smithson, David; Tu, Ying; Boulos, Nidal; Jacob, Melissa R; Shelat, Anang A; Wu, Yunshan; Ravu, Ranga Rao; Gilbertson, Richard; Avery, Mitchell A; Khan, Ikhlas A; Walker, Larry A; Guy, R Kiplin; Li, Xing-Cong

2014-04-25

62

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

PubMed

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

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

2014-10-01

63

Metabolite profiling of Angelica gigas from different geographical origins using 1H NMR and UPLC-MS analyses.  

PubMed

Angelica gigas obtained from different geographical regions was characterized using (1)H nuclear magnetic resonance (NMR) spectroscopy and ultraperformance liquid chromatography-mass spectrometry (UPLC-MS) followed by multivariate data analyses. Principal component analysis (PCA) and orthogonal partial least-squares-discriminant analysis (OPLS-DA) score plots from (1)H NMR and UPLC-MS data sets showed a clear distinction among A. gigas from three different regions in Korea. The major metabolites that contributed to the discrimination factor were primary metabolites including acetate, choline, citrate, 1,3-dimethylurate, fumarate, glucose, histamine, lactose, malate, N-acetylglutamate, succinate, and valine and secondary metabolites including decursin, decursinol, nodakenin, marmesin, 7-hydroxy-6-(2R-hydroxy-3-methylbut-3-ethyl)coumarin in A. gigas roots. The results demonstrate that (1)H NMR and UPLC-MS-based metabolic profiling coupled with chemometric analysis can be used to discriminate the geographical origins of various herbal medicines and to identify primary and secondary metabolites responsible for discrimination. PMID:21774558

Kim, Eun Jin; Kwon, Joseph; Park, Seong Hwa; Park, Chiyoul; Seo, Young-Bae; Shin, Hyun-Kyoo; Kim, Ho Kyoung; Lee, Kwang-Sik; Choi, Sang-Yun; Ryu, Do Hyun; Hwang, Geum-Sook

2011-08-24

64

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

PubMed

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

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

2013-10-01

65

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

PubMed

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

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

2014-08-13

66

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

PubMed

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

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

2014-11-01

67

Quantitative Determination of Fluconazole by Ultra-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS) in Human Plasma and its Application to a Pharmacokinetic Study.  

PubMed

In this study, a simple, rapid and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method is described for determination of fluconazole (FLA) in human plasma samples using phenacetin as the internal standard (IS). Sample preparation was accomplished through one-step protein precipitation by methanol, and chromatographic separation was performed on an Acquity BEH C18 column (2.1?mm×50?mm, 1.7??m) with mobile phase consisted of acetonitrile and water containing 0.1% formic acid (40:60, v/v) at a flow of 0.45?mL/min. Mass spectrometric analysis was performed using a QTrap 5500 mass spectrometer coupled with an electro-spray ionization (ESI) source in the positive ion mode. The MRM transition of m/z 307.2?238.2 was used to quantify for FLA. The linearity of this method was found to be within the concentration range of 10-6?000?ng/mL for FLA in human plasma. Only 1.0?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 FLA in healthy Chinese volunteers after oral administration. PMID:25093302

Song, J-J; Li, W; Wang, Z; Tian, D-D; Yin, W-Y

2015-01-01

68

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

PubMed Central

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

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

2014-01-01

69

[Plasma concentration and pharmacokinetics of ursolic acid carried in self-microemulsifying drug delivery system in rats studied by UPLC-MS/MS].  

PubMed

This study is to report the establishment of an UPLC-MS/MS method for the determination of plasma concentration of UA carried in self-microemulsifying drug delivery system (SMEDDS) and its pharmacokinetics in rats. It was used for determination and analysis when serum with internal standard was extracted from C18 solid-phase column. Acquity UPLC BEH C18 column (100 mm x 2.1 mm, 1.7 microm) was used for separation. The mobile phase was acetonitrile -0.1% ammonia with gradient elution at the flow rate of 0.2 mL x min(-1). The column temperature was 40 degrees C and the detection wave length was 210 nm. It was detected by negative ion using electrospray ionization source (ESI) and scanned by multiple reaction ion monitoring (MRM) mode. The liner relationship of UA was very good in the range of 1.19-3 815.00 ng x mL(-1) (r = 0.999 0). Recovery rate of different concentrations were 87.42%-89.95%. The precision of inter-day and intra-day were less than 11%. The method developed in our study was proved to be sensitive, rapid and simple. It is suitable for the pharmacokinetic study of UA-SMEDDS in rats. PMID:25212044

Chen, Hai-Xia; Xu, Xin-Gang; Han, Yuan-Yuan; Liu, Jin; Sheng, Li-Song; Sun, Dan-Dan; Zhao, Xu-Jie; Yan, Xue-Sheng

2014-06-01

70

[UPLC-MS/MS determination of content of three iridoids of xingnaojing oral preparation in rat brains and study on their brain pharmacokinetics].  

PubMed

To establish a UPLC-MS/MS method for the simultaneous determination of geniposide, genipin 1-O-beta-D-gentiobioside and geniposidic acid in rat brains and study the brain pharmacokinetics of the three iridoid glycosides in stroke rat after the oral administration of Xingnaojing. In this experiment, brain samples were precipitated with protein for twice. Acquity BEH C18 column was adopted, with acetonitrile-0.1% formic acid-water as the mobile phase for gradient elution. ESI source was adopted for mass spectra; multiple reaction monitoring (MRM) was conducted to detect negative ions. The time for sample analysis was 3.5 min. the results showed good linear relations among the three iridoid glycosides, with the extraction recovery between 99.6% and 114.3%, good intra- and inter-day precisions and accuracies and stability in line with the requirements. The t1/2 and MRT in the three components were similar in brains of stroke rats. Geniposide and genipin 1-O-beta-D-gentiobioside showed double peaks; where as geniposidic acid showed a single peak. In conclusion, the method is so specific, sensitive, accurate and reliable that it can be used to study the brain pharmacokinetics of Xingnaojing oral preparation. PMID:25244774

Xu, Pan; Du, Shou-Ying; Lu, Yang; Bai, Jie; Liu, Hui-Min; Du, Qiu; Chen, Zhen-Zhen; Wang, Zhen

2014-06-01

71

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

PubMed

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

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

2012-03-01

72

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

PubMed

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

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

2015-04-15

73

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...

74

Simultaneous determination of Guanfu base G and its active metabolites by UPLC-MS/MS in rat plasma and its application to a pharmacokinetic study.  

PubMed

To establish a rapid and sensitive ultra performance liquid chromatography mass spectrometry (UPLC-MS/MS) method for the determination of concentration of guanfu base G (GFG) and its active metabolites in rat plasma. The GFG and its active metabolites and the internal standard (phenacetin) were separated on an Acquity UPLC(®) BEH C18 chromatography column (2.1mm×50mm I.D., 1.7?m) using gradient elution with a mobile phase of methanol and ultrapure water at a flow rate of 0.4mL/min. The detection was performed on a Xevo triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) mode to monitor the precursor-to-product ion transitions of m/z 472.26?m/z 310.03 for GFG and m/z 180.00?m/z 109.99 for phenacetin (IS) using a positive electrospray ionization interface. The lower limit of quantification (LLOQ) was 1ng/mL, the limit of detection (LOD) was 0.3ng/mL, and the linear calibration curve was obtained over the concentration range of 1-200ng/mL. The intra-day and inter-day assay variations were measured to be below 10.97%, and the accuracy values (relative error) ranged from 95.4% to 103.6%. After validation, this method was successfully applied to a pharmacokinetic study where rats were intravenous administration of 5mg/kg GFG. A simple, rapid, sensitive, and accurate method for the determination of the concentration of GFG and its metabolites in rat plasma was developed and validated. PMID:24636893

Zhang, Lingchun; Wang, Aiqin; Wang, Xueqin; Zhang, Ying; Li, Xiaotian; Liu, Ping

2014-04-15

75

A validated, rapid UPLC-MS/MS method for simultaneous ivabradine, reboxetine, and metoprolol analysis in human plasma and its application to clinical trial samples.  

PubMed

A recent clinical trial assessing human autonomic cardiovascular regulation applied pacemaker channel inhibition with ivabradine, norepinephrine transporter blockade with reboxetine, and beta-adrenoreceptor blockade with metoprolol. To verify patient adherence, we developed and validated a fast UPLC-MS/MS assay measuring all three compounds simultaneously. Deuterium-labeled drugs, d3-ivabradine, d5-reboxetine and d7-metoprolol, served as internal standards. Sample preparation of 200?L human plasma consisted of a single liquid-liquid extraction step by means of ethyl acetate. Chromatographic separation was performed on a 50-mm long BEH C18 column with gradient elution using a mixture of water and methanol each containing 2mM ammonium acetate over 4.5min. The mass spectrometer was operated in the positive electrospray ionization (ESI+) mode. Characteristic product ions resulting from collision-induced dissociation of unlabeled and deuterium-labeled drugs with argon were used for quantification in the selected-reaction monitoring mode. We validated the method according to the European Medicines Agency (EMA) guideline on bioanalytical method validation over the range from 1ng/mL to 500ng/mL for all three analytes. Linear responses with correlation coefficients>0.99 over that range were acquired. The LOQ value was 1ng/mL for each drug. Regulatory criteria for accuracy (80-120%) and precision (RSD<15%) were met for all drugs. The internal standard-normalized matrix factor was close to 1 for low and high analyte concentrations. We successfully measured ivabradine, reboxetine, and metoprolol concentrations in 107 human plasma samples from a clinical trial. Quality control samples processed in parallel confirmed the method's reliability in a clinical setting. PMID:23434314

Zoerner, Alexander A; Schroeder, Christoph; Kayacelebi, Arslan Arinc; Suchy, Maria T; Gutzki, Frank-Mathias; Stichtenoth, Dirk O; Tank, Jens; Jordan, Jens; Tsikas, Dimitrios

2013-05-15

76

Development of an UPLC-MS/MS method for the determination of antibiotic ertapenem on dried blood spots.  

PubMed

Ertapenem (Invanz) is a newly developed carbapenem ?-lactam antimicrobial agent. The drug usage in pediatric age needs an accurate drug monitoring for effective patient management. The aim of this study was to evaluate the use of dried blood spot (DBS) specimens to measure ertapenem concentration during treatment. The analysis was performed by UPLC-MS/MS operating in multiple reaction monitoring (MRM) mode. The calibration curve in matrix was linear in the concentration range of 0.5-100 mg/L with correlation coefficient value higher than 0.997. Performance parameters of this method like lower limit of detection (LLOD, 0.2 mg/L), lower limit of quantification (LLOQ, 0.5 mg/L), matrix effect (20%), intra- and inter-day imprecision (CV within than 15%) and accuracy (between 94 and 155%) of drug concentrations have been evaluated. The drug stability at different temperatures was tested for one month, to evaluate the risks of sample delivery at different climatic conditions. The reported method allows now ertapenem analysis and offers many advantages for patients including the possibility of collecting samples at home. This new assay is both precise and accurate and is especially suitable for therapeutic drug monitoring and pharmacokinetic studies in neonates in whom obtaining larger blood samples is not convenient or possible. PMID:22226041

la Marca, Giancarlo; Giocaliere, Elisa; Villanelli, Fabio; Malvagia, Sabrina; Funghini, Silvia; Ombrone, Daniela; Filippi, Luca; De Gaudio, Marina; De Martino, Maurizio; Galli, Luisa

2012-03-01

77

Analysis of lipid peroxidation biomarkers in extremely low gestational age neonate urines by UPLC-MS/MS.  

PubMed

Extremely low gestational age neonates (ELGAN) frequently require the use of oxygen supply in the delivery room leading to systemic inflammation and oxidative stress that are responsible for increased morbidity and mortality. The objective of this study was to establish reference ranges of a set of representative isoprostanes and prostaglandins, which are stable biomarkers of lipid peroxidation often correlated with oxidative stress-related disorders. First, a quantitative ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. The proposed analytical method was tailored for its application in the field of neonatology, enabling multi-analyte detection in non-invasive, small-volume urine samples. Then, the lipid peroxidation product concentrations in a total of 536 urine samples collected within the framework of two clinical trials including extremely low gestational age neonates (ELGAN) were analyzed. The access to a substantially large number of samples from this very vulnerable population provided the chance to establish reference ranges of the studied biomarkers. Up to the present, and for this population, this is the biggest reference data set reported in literature. Results obtained should assist researchers and pediatricians in interpreting test results in future studies involving isoprostanes and prostaglandins, and could help assessing morbidities and evaluate effectiveness of treatment strategies (e.g., different resuscitation conditions) in the neonatal field. PMID:24817352

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

2014-07-01

78

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

PubMed

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

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

2014-03-01

79

Simultaneous Detection of Multiple DNA Adducts in Human Lung Samples by Isotope-Dilution UPLC-MS/MS.  

PubMed

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

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

2014-12-01

80

Simultaneous determination of cyromazine and dicyclanil in animal edible tissues using UPLC-MS/MS.  

PubMed

Cyromazine and dicyclanil are both used as insect growth regulators. This paper describes an easy and innovative simultaneous extraction method for residues of cyromazine and dicyclanil in food of animal origin, and a confirmation procedure using UHPLC-MS/MS. The sample was extracted, deproteinised by 1% trichloracetic acid in water-acetonitrile, followed by selective defatting using hexane based on the degree of matrix complexity; cleaned-up on an mixed-mode cation exchange (MCX) cartridge; and quantified by using matrix-matched calibration. The mean recoveries were all between 62.0% and 99.2%, and the RSDs were all below 9.94%. The present method was rapid, sensitive and reliable, which was applied to the quantitative analysis of these residues in animal tissues. PMID:23469982

Hou, Xiaolin; Zhou, Degang; Huai, Wenhui; Beier, Ross C; Sun, Yingjian; Lu, Yan; Wu, Guojuan; Sun, Zhiwen; Wu, Yongning

2013-01-01

81

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

PubMed

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

Bolechová, Martina; Cáslavský, Josef; Pospíchalová, Markéta; Kosubová, Petra

2015-03-01

82

Profiling of Serum Bile Acids in a Healthy Chinese Population Using UPLC-MS/MS.  

PubMed

Bile acids (BAs) are a group of important physiological agents for cholesterol metabolism, intestinal nutrient absorption, and biliary secretion of lipids, toxic metabolites, and xenobiotics. Extensive research in the last two decades has unveiled new functions of BAs as signaling molecules and metabolic regulators that modulate hepatic lipid, glucose, and energy homeostasis through the activation of nuclear receptors and G-protein-coupled receptor signaling in gut-liver metabolic axis involving host-gut microbial co-metabolism. Therefore, investigation of serum BA profiles, in healthy human male and female subjects with a wide range of age and body mass index (BMI), will provide important baseline information on the BA physiology as well as metabolic homeostasis among human subjects that are regulated by two sets of genome, host genome, and symbiotic microbiome. Previous reports on age- or gender-related changes on BA profiles in animals and human showed inconsistent results, and the information acquired from various studies was highly fragmentary. Here we profiled the serum BAs in a large population of healthy participants (n = 502) and examined the impact of age, gender, and BMI on serum BA concentrations and compositions using a targeted metabonomics approach with ultraperformance liquid chromatography triple-quadrupole mass spectrometry. We found that the BA profiles were dependent on gender, age, and BMI among study subjects. The total BAs were significantly higher in males than in females (p < 0.05) and higher in obese females than in lean females (p < 0.05). The difference in BA profiles between male and female subjects was decreased at age of 50-70 years, while the difference in BA profiles between lean and obese increased for subjects aged 50-70 years. The study provides a comprehensive understanding of the BA profiles in healthy subjects and highlights the need to take into account age, gender, and BMI differences when investigating pathophysiological changes of BAs resulting from gastrointestinal diseases. PMID:25581415

Xie, Guoxiang; Wang, Yixing; Wang, Xiaoning; Zhao, Aihua; Chen, Tianlu; Ni, Yan; Wong, Linda; Zhang, Hua; Zhang, Jue; Liu, Chang; Liu, Ping; Jia, Wei

2015-02-01

83

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

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

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

2014-05-13

84

Simultaneous determination of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid and geniposide in rat plasma by UPLC-MS/MS and its application to a pharmacokinetic study after administration of Reduning injection.  

PubMed

A simple, specific and sensitive ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method was established and validated for simultaneous determination of neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid and geniposide in rat plasma using puerarin as an internal standard (IS). Plasma samples were pretreated by a one-step direct protein precipitation procedure with acetonitrile after acidified using as little as 50??L plasma. Chromatographic separation was performed on an Acquity BEH C18 column (100?×?2.1?mm, 1.7?µm) at a flow rate of 0.2?mL/min by a gradient elution, using 0.2% acetic acid-methanol as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring via electrospray ionization source with negative ion mode. Calibration curves showed good linearity (r?>?0.995) over wide concentration ranges. The intra- and inter-day precisions were <15%, and the accuracy was within ±8.0%. The validated method was successfully applied to a pharmacokinetic study of the four bioactive components in rats after intravenous administration of Reduning injection. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24842397

Wang, Yanjuan; Wen, Jing; Zheng, Weihua; Zhao, Longshan; Fu, Xiaohuan; Wang, Zhenzhong; Xiong, Zhili; Li, Famei; Xiao, Wei

2015-01-01

85

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

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

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

2014-07-01

86

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

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 (50mm×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 0.2ml/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 1-1000ng/ml for TAP and 0.5-500ng/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

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

2015-02-01

87

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

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

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

2014-01-01

88

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

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

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

2013-12-01

89

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

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. Copyright © 2014 John Wiley & Sons, Ltd. PMID:25042570

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

2015-03-01

90

Simultaneous UPLC-MS/MS quantification of the endocannabinoids 2-arachidonoyl glycerol (2AG), 1-arachidonoyl glycerol (1AG), and anandamide in human plasma: minimization of matrix-effects, 2AG/1AG isomerization and degradation by toluene solvent extraction.  

PubMed

Analysis of the endocannabinoid (EC) system's key molecules 2-arachidonoyl glycerol (2AG) and arachidonoyl ethanolamide (anandamide, AEA) is challenging due to several peculiarities. 2AG isomerizes spontaneously to its biologically inactive analogue 1-arachidonoyl glycerol (1AG) by acyl migration and it is only chromatographically distinguishable from 1AG. Matrix-effects caused primarily by co-extracted phospholipids may further compromise analysis. In addition, 2AG and 1AG are unstable under certain conditions like solvent evaporation or reconstitution of dried extracts. We examined effects of different organic solvents and their mixtures, such as toluene, ethyl acetate, and chloroform-methanol, on 2AG/1AG isomerisation, 2AG/1AG stability, and matrix-effects in the UPLC-MS/MS analysis of 2AG and AEA in human plasma. Toluene prevented, both, 2AG isomerisation to 1AG and degradation of 2AG/1AG during evaporation. Toluene extracts contain only 2% of matrix-effect-causing plasma phospholipids compared to extracts from the traditionally used solvent mixture chloroform-methanol. Toluene and all other tested organic solvents provide comparable 2AG and AEA extraction yields (60-80%). Based on these favourable toluene properties, we developed and validated a UPLC-MS/MS method with positive electrospray ionization (ESI+) that allows for simultaneous accurate and precise measurement of 2AG and AEA in human plasma. The UPLC-MS/MS method was cross-validated with a previously described fully-validated GC-MS/MS method for AEA in human plasma. A close correlation (r(2)=0.821) was observed between the results obtained from UPLC-MS/MS (y) and GC-MS/MS (x) methods (y=0.01+0.85x). The UPLC-MS/MS method is suitable for routine measurement of 2AG and AEA in human plasma samples (1 mL) in clinical settings as shown by quality control plasma samples processed over a period of 100 days. The UPLC-MS/MS method was further extended to human urine. In urine, AEA was not detectable and 2AG was detected in only 3 out of 19 samples from healthy subjects at 160, 180 and 212 pM corresponding to 12.3, 14.5 and 9.9 pmol/mmol creatinine, respectively. PMID:21752730

Zoerner, Alexander A; Batkai, Sandor; Suchy, Maria-Theresia; Gutzki, Frank-Mathias; Engeli, Stefan; Jordan, Jens; Tsikas, Dimitrios

2012-02-01

91

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

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

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

2013-01-01

92

A rapid miniaturized residue analytical method for the determination of zoxamide and its two acid metabolites in ginseng roots using UPLC-MS/MS.  

PubMed

A miniaturized residue method was developed for the analysis of the fungicide zoxamide and its metabolites in dried ginseng root. The zoxamide metabolites, 3,5-dichloro-1,4-benzenedicarboxylic acid (DCBC) and 3,5-dichloro-4-hydroxymethylbenzoic acid (DCHB), are small acid molecules that have not been previously extracted from the ginseng matrix with common multiresidue methods. The presented extraction method effectively and rapidly recovers both the zoxamide parent compound and its acid metabolites from fortified ginseng root. The metabolites are extracted with an alkaline glycine buffer and the aqueous ginseng mixture is partitioned with ethyl acetate. In addition, this method avoids the use of derivatization of the small acid molecules by using UPLC-MS/MS instrumental analysis. In a quantitative validation of the analytical method at three levels for zoxamide (0.007 (LOD), 0.02 (LOQ), and 0.2 mg/kg) and four levels (0.07 (LOD), 0.2 (LOQ), and 0.6 and 6 mg/kg) for both metabolites, acceptable method performances were achieved with recoveries ranging from 86 to 107% (at levels of LOQ and 3×, 10×, and 30× the LOQ) with <20% RSD for the three analytes in accordance with international guidelines.1. PMID:24552297

Podhorniak, Lynda V

2014-04-30

93

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

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

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

2013-01-01

94

Simultaneous Determination of Typhaneoside and Isorhamnetin-3-O-Neohesperidoside in Rats After Oral Administration of Pollen Typhae Extract by UPLC-MS/MS.  

PubMed

For the first time, a selective and rapid ultra-performance liquid chromatography method with tandem mass spectrometric (UPLC-MS/MS) detection for simultaneous determination of typhaneoside and isorhamnetin-3-O-neohesperidoside in rat plasma was developed and validated, which was applied to the pharmacokinetic study of Pollen Typhae extract. The separation was carried out on an ACQUITY UPLC(TM) BEH C18 column with gradient elution using mobile phase including acetonitrile and water (containing 0.1% formic acid). The flow rate was 0.4 mL/min. The detection was conducted by means of electrospray ionization mass spectrometry in negative ion mode with multiple reaction monitoring. The assays were linear over the concentration range of 0.5-100 ng/mL, and the lower limit of quantification was 0.5 ng/mL for typhaneoside and isorhamnetin-3-O-neohesperidoside. The method was validated in terms of intra- and interday precision (<9.37%), accuracy (within ±10.91%), linearity, specificity and stability, and has been successfully applied to a pharmacokinetic study of Pollen Typhae extract in rats after oral administration. PMID:25349196

Cao, Sali; Ni, Boran; Feng, Lijun; Yin, Xingbin; Dou, Haoran; Fu, Jing; Lin, Longfei; Ni, Jian

2014-10-27

95

Determination of tapentadol and tapentadol-O-glucuronide in human serum samples by UPLC-MS/MS.  

PubMed

Tapentadol is a novel, centrally acting analgesic with 2 mechanisms of action, MOR agonism and noradrenaline (NA) reuptake inhibition in a single molecule. It is the first member of a new therapeutic class, MOR-NRI. A high throughput liquid chromatography-tandem mass spectrometric (LC-MS/MS) assay was developed and validated for the quantitative analysis of tapentadol and its O-glucuronide metabolite in human serum. Simultaneous quantification was deemed to be challenging because of the large difference in concentrations between tapentadol and its O-glucuronide metabolite in clinical samples. Therefore, a method was established using a common processed sample, but with different injection volumes and chromatographic conditions for each analyte. Tapentadol and tapentadol-O-glucuronide were determined by protein precipitation of 0.100ml of the samples with acetonitrile. The internal standards used are D6-tapentadol and D6-tapentadol-O-glucuronide. The validated concentration range was 0.200-200ng/ml (tapentadol) and 10.0-10,000ng/ml (tapentadol-O-glucuronide). Chromatographic separation was achieved by gradient elution on a Waters Acquity UPLC BEH C18 (1.7?m, 2.1×50mm) column, with mobile phase consisting of 0.01M ammonium formate (adjusted to pH 4 using formic acid) (A) and methanol (B). A separate injection was done for measurement of each analyte, with a different gradient and run time. The analytes were detected by using an electrospray ion source on a triple quadrupole mass spectrometer operating in positive ionization mode. The run time was 1.6min for tapentadol and 1.5min for tapentadol-O-glucuronide. The high sensitivity and acceptable performance of the assay allowed its application to the analysis of serum samples in clinical trials. The validated method was used for analysis of tapentadol in over 17,000 samples. PMID:25600054

Hillewaert, Vera; Pusecker, Klaus; Sips, Luc; Verhaeghe, Tom; de Vries, Ronald; Langhans, Manfred; Terlinden, Rolf; Timmerman, Philip

2015-02-15

96

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...

97

High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography–tandem mass spectrometry in the positive and negative ionization modes  

Microsoft Academic Search

In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma\\u000a by ultra-performance liquid chromatography–tandem mass spectrometry (UPLC-MS\\/MS) in the positive and negative ionization modes\\u000a using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with\\u000a an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with

Tadashi Ogawa; Hideki Hattori; Rina Kaneko; Kenjiro Ito; Masae Iwai; Yoko Mizutani; Tetsuya Arinobu; Akira Ishii; Hiroshi Seno

2011-01-01

98

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

PubMed

An UPLC-MS/MS method using ESI+ionization and MRM was developed and fully validated according to international guidelines for the qualitative and quantitative analysis of nine synthetic cannabinoids and/or their metabolites in urine samples (1mL). Prior to extraction the samples were subjected to an enzymatic hydrolysis using ?-glucuronidase followed by a SPE procedure using Oasis(®) HLB 3cc (60mg) columns. The chromatographic separation was performed with an Acquity UPLC(®) HSS T3 (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

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

2014-10-01

99

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

PubMed

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

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

2014-04-01

100

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

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

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

2013-12-15

101

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

PubMed

A rapid and sensitive method based on solid phase extraction and ultra performance liquid chromatography-electrospray ionization tandem mass spectrometry (UPLC-ESI-MS/MS) for the simultaneous determination of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine, 3,4-methylene-dioxymethamphetamine, N-methyl-1-(3,4-methyl-enedioxyphenyl)-2-butanamine, 3,4-methylenedioxyethylamphetamine, p-methoxymethamphetamine, ephedrine, N-methylephedrine, cathinone, methcathinone, and ketamine in whole blood and urine was developed and validated. Following solid phase extraction, the analytes were separated on ACQUITY UPLC BEH Phenyl column (100mm×2.1mm, 1.7?m) under gradient elution using a mobile phase containing of acetonitrile and 0.3% formic acid in water at a flow rate of 0.4mLmin(-1) and analyzed by a triplequadrupole mass spectrometer in the multiple reaction monitoring (MRM) mode. The proposed method was linear for each analyte with correlation coefficients over 0.99. Recovery validation studies showed accuracy bias below 4.4%. Acceptable precision was also obtained with a relative standard deviation below 8.9%. The sensitivity of the assay was found to be adequate for the quantitation of the illicit drugs in whole blood and urine sample and was higher than reported methods. The present method was proved to be reliable and robust for drug screening in forensic toxicological analysis. PMID:24631805

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

2014-04-01

102

Urinary Metabolic Biomarker and Pathway Study of Hepatitis B Virus Infected Patients Based on UPLC-MS System  

PubMed Central

Hepatitis B virus (HBV) is the fatal consequence of chronic hepatitis, and lack of biomarkers has been a long standing bottleneck in the clinical diagnosis. Metabolomics concerns with comprehensive analysis of small molecules and provides a powerful approach to discover biomarkers in biological systems. Here, we present metabolomics analysis applying ultra-performance liquid chromatography/electrospray ionization quadruple time-of-flight mass spectrometry. (UPLC-Q-TOF-HDMS) to determine metabolite alterations in HBV patients. Most important permutations are elaborated using multivariate statistical analysis and network analysis that was used to select the metabolites for the noninvasive diagnosis of HBV. In this study, the total 11 urinary differential metabolites were identified and contributed to HBV progress involving several key metabolic pathways by using pathway analysis with MetPA, which are promising biomarker candidates for diagnostic research. More importantly, of 11 altered metabolites, 4 metabolite markers were effective for the diagnosis of human HBV, achieved a satisfactory accuracy, sensitivity and specificity, respectively. It demonstrates that metabolomics has the potential as a non-invasive tool to evaluate the potential of these metabolites in the early diagnosis of HBV patients. These findings may be promising to yield a valuable insight into the pathophysiology of HBV and to advance the approaches of diagnosis, treatment, and prevention. PMID:23696887

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

2013-01-01

103

Determination of bioactive components in Chinese herbal formulae and pharmacokinetics of rhein in rats by UPLC-MS/MS.  

PubMed

Rhein (4,5-dihydroxy-9,10-dioxoanthracene-2-carboxylic acid, cassic acid) is a pharmacological active component found in Rheum palmatum L. the major herb of San-Huang-Xie-Xin-Tang (SHXXT), a medicinal herbal product used as a remedy for constipation. Here we have determined multiple bioactive components in SHXXT and investigated the comparative pharmacokinetics of rhein in rats. A sensitive and specific method combining liquid chromatography with electrospray ionization tandem mass spectrometry has been developed and validated to simultaneously quantify six active compounds in the pharmaceutical herbal product SHXXT to further study their pharmacokinetics in rats. Multiple reaction monitoring (MRM) was employed for quantification with switching electrospray ion source polarity between positive and negative modes in a single run. There were no significant matrix effects in the quantitative analysis and the mean recovery for rhein in rat plasma was 91.6%±3.4%. The pharmacokinetic data of rhein demonstrate that the herbal formulae or the single herbal extract provide significantly higher absorption rate than the pure compound. This phenomenon suggests that the other herbal ingredients of SHXXT and rhubarb extract significantly enhance the absorption of rhein in rats. In conclusion, the herbal formulae (SHXXT) are more efficient than the single herb (rhubarb) or the pure compound (rhein) in rhein absorption. PMID:24699148

Hou, Mei-Ling; Chang, Li-Wen; Lin, Chi-Hung; Lin, Lie-Chwen; Tsai, Tung-Hu

2014-01-01

104

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

PubMed

The current study aims to investigate the pharmacokinetic study of eight caffeic acid derivatives (forsythoside A, isoforsythoside, forsythoside B, neochlorogenic acid, chlorogenic acid, cryptochlorogenic acid, 3,5-dicaffeoylquinic acid and 3,4-dicaffeoylquinic acid) following oral administration of Flos Lonicerae-Fructus Forsythiae herb combination in rats. A rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed to determine the eight caffeic acid derivatives simultaneously in rat plasma. After mixing with the internal standard (IS) tinidazole, plasma samples were pretreated by liquid-liquid extraction with n-butyl alcohol/ethyl acetate (7:3, v/v). The separation was performed on an Acquity UPLC HSS T3 C18 column (100mm×2.1mm, 1.8?m) at a flow rate of 0.4mLmin(-1), and acetonitrile/methanol (4:1, v/v)-0.4% formic acid was used as mobile phase. The detection was performed on a triple quadrupole tandem mass spectrometer by multiple reaction monitoring (MRM) via electrospray ionization (ESI) source with positive and negative ionization modes. All calibration curves had good linearity (r>0.991) over the concentration ranges of 1.097-2246ngmL(-1) for neochlorogenic acid, 6.535-6692ngmL(-1) for chlorogenic acid, 2.103-2153ngmL(-1) for cryptochlorogenic acid, 0.5058-129.5ngmL(-1) for 3,5-dicaffeoylquinic acid, 0.3205-82.05ngmL(-1) for 3,4-dicaffeoylquinic acid, 1.002-512.8ngmL(-1) for isoforsythoside, 0.4795-982.1ngmL(-1) for forsythoside A and 0.7587-776.9ngmL(-1) for forsythoside B, respectively. The intra- and inter-batch precisions were all within 15% and the accuracy (relative error, RE%) all ranged from 85.68% to 114.7%. It was shown from pharmacokinetic parameters that the rank order of AUC0-t, Cmax and T1/2k for phenolic acids was chlorogenic acid>neochlorogenic acid?cryptochlorogenic acid>3,4-dicaffeoylquinic acid?3,5-dicaffeoylquinic acid (most of them had significant differences), which corresponded to their administration dosages to rats, but that of MRT0-t and T1/2z were opposite. Besides, the AUC0-t, Cmax, MRT and T1/2z except T1/2k of isoforsythoside and forsythoside B had no significant difference, compared to that of forsythoside A though their administration dosages were significantly lower than that of forsythoside A. All results showed that the method was applied to the pharmacokinetic study of the eight caffeic acid derivatives in rat plasma successfully after oral administration of Flos Lonicerae-Fructus Forsythiae herb combination, and there were significant differences of caffeic acid derivatives even isomers in the pharmacokinetic parameters. PMID:24441018

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

2014-02-15

105

Development and validation of a sample stabilization strategy and a UPLC-MS/MS method for the simultaneous quantitation of acetylcholine (ACh), histamine (HA), and its metabolites in rat cerebrospinal fluid (CSF).  

PubMed

A UPLC-MS/MS assay was developed and validated for simultaneous quantification of acetylcholine (ACh), histamine (HA), tele-methylhistamine (t-mHA), and tele-methylimidazolacetic acid (t-MIAA) in rat cerebrospinal fluid (CSF). The biological stability of ACh in rat CSF was investigated. Following fit-for-purpose validation, the method was applied to monitor the drug-induced changes in ACh, HA, t-mHA, and t-MIAA in rat CSF following administration of donepezil or prucalopride. The quantitative method utilizes hydrophilic interaction chromatography (HILIC) Core-Shell HPLC column technology and a UPLC system to achieve separation with detection by positive ESI LC-MS/MS. This UPLC-MS/MS method does not require extraction or derivatization, utilizes a stable isotopically labeled internal standard (IS) for each analyte, and allows for rapid throughput with a 4 min run time. Without an acetylcholinesterase (AChE) inhibitor present, ACh was found to have 1.9±0.4 min in vitro half life in rat CSF. Stability studies and processing modification, including the use of AChE inhibitor eserine, extended this half life to more than 60 min. The UPLC-MS/MS method, including stabilization procedure, was validated over a linear concentration range of 0.025-5 ng/mL for ACh and 0.05-10 ng/mL for HA, t-mHA, and t-MIAA. The intra-run precision and accuracy for all analytes were 1.9-12.3% CV and -10.2 to 9.4% RE, respectively, while inter-run precision and accuracy were 4.0-16.0% CV and -5.3 to 13.4% RE, respectively. By using this developed and validated method, donepezil caused increases in ACh levels at 0.5, 1, 2, and 4h post dose as compared to the corresponding vehicle group, while prucalopride produced approximately 1.6- and 3.1-fold increases in the concentrations of ACh and t-mHA at 1h post dose, respectively, compared to the vehicle control. Overall, this methodology enables investigations into the use of CSF ACh and HA as biomarkers in the study of these neurotransmitter systems and related drug discovery efforts. PMID:21684223

Zhang, Yanhua; Tingley, F David; Tseng, Elaine; Tella, Max; Yang, Xin; Groeber, Elizabeth; Liu, Jianhua; Li, Wenlin; Schmidt, Christopher J; Steenwyk, Rick

2011-07-15

106

High-Sensitivity Spectrophotometry.  

ERIC Educational Resources Information Center

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

Harris, T. D.

1982-01-01

107

Ultra-Performance Liquid Chromatography Mass Spectrometry and Sensitive Bioassay Methods for Quantification of Posaconazole Plasma Concentrations after Oral Dosing?  

PubMed Central

Posaconazole (POS) is a new antifungal agent for prevention and therapy of mycoses in immunocompromised patients. Variable POS pharmacokinetics after oral dosing may influence efficacy: a trough threshold of 0.5 ?g/ml has been recently proposed. Measurement of POS plasma concentrations by complex chromatographic techniques may thus contribute to optimize prevention and management of life-threatening infections. No microbiological analytical method is available. The objective of this study was to develop and validate a new simplified ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) method and a sensitive bioassay for quantification of POS over the clinical plasma concentration range. The UPLC-MS/MS equipment consisted of a triple quadrupole mass spectrometer, an electrospray ionization (ESI) source, and a C18 analytical column. The Candida albicans POS-hypersusceptible mutant (MIC of 0.002 ?g/ml) ?cdr1 ?cdr2 ?flu ?mdr1 ?can constructed by targeted deletion of multidrug efflux transporters and calcineurin genes was used for the bioassay. POS was extracted from plasma by protein precipitation with acetonitrile-methanol (75%/25%, vol/vol). Reproducible standard curves were obtained over the range 0.014 to 12 (UPLC-MS/MS) and 0.028 to 12 ?g/ml (bioassay). Intra- and interrun accuracy levels were 106% ± 2% and 103% ± 4% for UPLC-MS/MS and 102% ± 8% and 104% ± 1% for bioassay, respectively. The intra- and interrun coefficients of variation were 7% ± 4% and 7% ± 3% for UPLC-MS/MS and 5% ± 3% and 4% ± 2% for bioassay, respectively. An excellent correlation between POS plasma concentrations measured by UPLC-MS/MS and bioassay was found (concordance, 0.96). In 26 hemato-oncological patients receiving oral POS, 27/69 (39%) trough plasma concentrations were lower than 0.5 ?g/ml. The UPLC-MS/MS method and sensitive bioassay offer alternative tools for accurate and precise quantification of the plasma concentrations in patients receiving oral posaconazole. PMID:20921320

Rochat, Bertrand; Pascual, Andres; Pesse, Benoît; Lamoth, Frédéric; Sanglard, Dominique; Decosterd, Laurent A.; Bille, Jacques; Marchetti, Oscar

2010-01-01

108

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

PubMed

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

Lin, Baiwei; Pease, Joseph H

2013-12-01

109

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

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 0.05-2ngL(-1) and 0.25-10ngkg(-1), respectively. The LOQ for the four mycotoxins in liquid milk and milk powder were 0.1-5ngL(-1) and 0.5-25ngkg(-1), respectively. PMID:25466104

Wang, Xiupin; Li, Peiwu

2015-04-15

110

Radix Paeoniae Rubra and Radix Paeoniae Alba Attenuate CCl4-Induced Acute Liver Injury: An Ultra-Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS) Based Metabolomic Approach for the Pharmacodynamic Study of Traditional Chinese Medicines (TCMs)  

PubMed Central

Metabolomics has been frequently used in pharmacodynamic studies, especially those on traditional Chinese medicine (TCM). Radix Paeoniae Alba and Radix Paeoniae Rubra are popularly used in TCM, and both have hepatoprotective effects. In this study, a CCl4-induced acute liver injury rat model was established and confirmed by the observed serum aminotransferase activities. The metabolomics approach was applied to study the influence of Radix Paeoniae Alba and Radix Paeoniae Rubra on the metabolic changes in rats with acute liver injury. The partial least-squares-discriminant analysis (PLS-DA) of rat serum and their ultra-performance liquid chromatography-mass spectrometry (UPLC-MS) fingerprints allowed discrimination of controlled, acute liver injury-model rats after administration of the two types of TCMs. The time-dependent PLS-DA plots showed that the changes in the metabolic patterns of the rats, which were administered with the TCMs, had stabilized within 2 h after they received the intraperitoneal CCl4 injection. The results indicated the protective effect of TCMs against liver injury. Several potential biomarkers were detected and identified, which included creatine, deoxycholic acid, choline, 5-methylenetetrahydrofolate, folic acid, and glycocholic acid. The physiological significance of these metabolic changes was discussed. PMID:23203085

Wang, Rui; Xiong, Ai-Zhen; Teng, Zhong-Qiu; Yang, Qi-Wei; Shi, Yan-Hong; Yang, Li

2012-01-01

111

A rapid UPLC-MS/MS method for simultaneous determination of flunitrazepam, 7-aminoflunitrazepam, methadone and EDDP in human, rat and rabbit plasma.  

PubMed

A simple, high-throughput, sensitive LC-ESI-MS/MS method is presented for the simultaneous determination of methadone (MET), flunitrazepam (FNZ) and their major metabolites, EDDP (2-ethilidene-1,5-dimethyl-3,3-diphenylpyrrolidone) and 7-aminoflunitrazepam (7-AFNZ), respectively, in human, rat and rabbit plasma. The isolation of the selected compounds involved a liquid-liquid extraction with ethyl acetate at a basic pH. Good chromatographic separation was achieved on a HSS T3 column (1.8 ?m particle size), with a 3 min gradient elution using a mixture of acetonitrile with 0.1% formic acid (solvent A) and 5mM ammonium acetate (solvent B) as the mobile phase. The tandem mass spectrometric detection was performed in multiple reaction monitoring (MRM) mode with ionization of the analytes in positive mode. The assay was fully validated according to current acceptance criteria for bioanalytical methods validation. It was proved to be linear in the range of 0.5-250 ng/mL, with adequate accuracy and precision over this range. Based on accuracy and CV% values the LOQ and ULOQ values were set at 0.509 ng/mL and 2036 ng/mL for MET, 0.520 ng/mL and 2080 ng/mL for EDDP, 0.524 ng/mL and 2096 ng/mL for FNZ and 0.528 ng/mL and 2114 ng/mL for 7-AFNZ, respectively. The method was tested for potential matrix effects, without observing significant ion suppression. The investigated compounds stability was examined in plasma at room temperature and after three freeze-thaw cycles and in the final extract when maintained at 4 °C in the autosampler. Potential stability issues were observed only for FNZ at room temperature. The method was successfully applied to quantify the selected compounds in human, rat and rabbit plasma samples, after exposure to FNZ or simultaneous exposure to FNZ and MET. PMID:22967607

Kiss, Béla; Bogdan, Catalina; Pop, Anca; Loghin, Felicia

2012-09-15

112

Direct Quantitative Analysis of a 20 kDa PEGylated Human Calcitonin Gene Peptide Antagonist in Cynomolgus Monkey Serum Using In-Source CID and UPLC-MS/MS  

NASA Astrophysics Data System (ADS)

PEGylation is a successful strategy to improve the pharmacokinetic and pharmaceutical properties of therapeutic peptides. However, quantitative analysis of PEGylated peptides in biomatrix by LC-MS/MS poses significant analytical challenge due to the polydispersity of the polyethylene glycol (PEG), and the multiple charge states observed for both the peptide and PEG moieties. In this report, a novel LC-MS/MS method for direct quantitative analysis of 20 kDa PEGylated CGRP[Cit, Cit] in cynomolgus monkey serum is presented. CGRP[Cit, Cit] is an investigational human calcitonin gene peptide receptor antagonist with amino acid sequence Ac -WVTH[Cit]LAGLLS[Cit]SGGVVRKNFVPT DVGPFAF- NH 2 . In-source collision-induced dissociation (in-source CID) of 20 kDa PEGylated peptide was used to generate CGRP[Cit, Cit] fragment ions, among which the most abundant b {8/+} ion was selected and measured as a surrogate for the 20 kDa PEGylated peptide. A solid phase extraction (SPE) method was used to extract the PEGylated peptides from the biomatrix prior to the UPLC-MS/MS analysis. This method achieved a lower limit of quantitation (LLOQ) of 5.00 ng/mL with a serum sample volume of 100 ?L, and was linear over the calibration range of 5.00 to 500 ng/mL in cynomolgus monkey serum. Intraday and interday accuracy and precision from QC samples were within ±15%. This method was successfully applied to a pharmacokinetic study of the 20 kDa PEGylated CGRP[Cit, Cit] in cynomolgus monkeys.

Li, Hongyan; Rose, Mark J.; Holder, Jerry Ryan; Wright, Marie; Miranda, Les P.; James, Christopher A.

2011-09-01

113

HILIC-UPLC-MS/MS combined with hierarchical clustering analysis to rapidly analyze and evaluate nucleobases and nucleosides in Ginkgo biloba leaves.  

PubMed

Ginkgo biloba leaf extract has been widely used in dietary supplements and more recently in some foods and beverages. In addition to the well-known flavonol glycosides and terpene lactones, G. biloba leaves are also rich in nucleobases and nucleosides. To determine the content of nucleobases and nucleosides in G. biloba leaves at trace levels, a reliable method has been established by using hydrophilic interaction ultra performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HILIC-UPLC-TQ-MS/MS) working in multiple reaction monitoring mode. Eleven nucleobases and nucleosides were simultaneously determined in seven min. The proposed method was fully validated in terms of linearity, sensitivity, and repeatability, as well as recovery. Furthermore, hierarchical clustering analysis (HCA) was performed to evaluate and classify the samples according to the contents of the eleven chemical constituents. The established approach could be helpful for evaluation of the potential values as dietary supplements and the quality control of G. biloba leaves, which might also be utilized for the investigation of other medicinal herbs containing nucleobases and nucleosides. Copyright © 2014 John Wiley & Sons, Ltd. PMID:24665003

Yao, Xin; Zhou, Guisheng; Tang, Yuping; Guo, Sheng; Qian, Dawei; Duan, Jin-Ao

2015-02-01

114

A Rapid and Simple UPLC-MS-MS Method for Determination of Glipizide in Human Plasma and Its Application to Bioequivalence Study.  

PubMed

In this study, a simple, rapid and sensitive ultra performance liquid chromatography-tandem mass spectrometry method is described for the determination of glipizide in human plasma samples using carbamazepine as the internal standard (IS) from bioequivalence assays. 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 rate of 0.4 mL/min. Mass spectrometric analysis was performed using an QTrap5500 mass spectrometer coupled with an electrospray ionization source in the positive ion mode. The multiple reaction monitoring transitions of m/z 446.1 ? 321.0 and m/z 237.1 ? 194.2 were used to quantify for glipizide and IS. The linearity of this method was found to be within the concentration range of 10-1,500 ng/mL for glipizide in human plasma. Only 1.0 min was needed for an analytical run. The method was applied to a bioequivalence study of two drug products containing glipizide in human plasma samples. PMID:24771054

Qiu, Xiangjun; Zheng, Shuang-Li; Wang, Yingfei; Wang, Rong; Ye, Lei

2015-01-01

115

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

PubMed

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

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

2014-02-01

116

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

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

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

2014-06-17

117

High-performance liquid chromatography with fluorescence detection and ultra-performance liquid chromatography with electrospray tandem mass spectrometry method for the determination of indoleamine neurotransmitters and their metabolites in sea lamprey plasma.  

PubMed

We present a comparison of two sensitive methods, HPLC with fluorescence detector (HPLC/FLD) and UPLC with electrospray tandem mass spectrometry (UPLC/MS/MS), for the determination of indoleamine neurotransmitters (NTs) and their metabolites in sea lamprey plasma samples. Liquid-liquid extraction (LLE) and solid-phase extraction (SPE) were also tested for recovery and matrix effect. The recoveries of SPE determined by HPLC/FLD and UPLC/MS/MS ranged from 75 to 123% and 78 to 105%, respectively, while the recoveries of LLE ranged from 45 to 73% and 48 to 75%, respectively. SPE combined with HPLC/FLD and UPLC/MS/MS to determine the target analytes in plasma samples were validated of the sensitivity, reproducibility, accuracy and precision. Both methods exhibited excellent linearity in the range of 0.2-50 ng mL(-1) for all analytes. The limits of detection (LOD) varied from 0.04 ng mL(-1) to 0.13 ng mL(-1) for HPLC/FLD method and 0.003 ng mL(-1) to 0.02 ng mL(-1) for UPLC/MS/MS method. The inter-day accuracy ranged from 82.5 to 127.0% for HPLC/FLD and 93.0 to 113.0% for UPLC/MS/MS. The inter-day precision ranged from 9.9 to 32.3% for HPLC/FLD and 5.4 to 13.2% for UPLC/MS/MS. These results demonstrated that the values obtained by both methods were within the satisfactory range and the UPLC/MS/MS method provided more accurate and precise measurements than HPLC/FLD method. The comparison is of great importance to determine the available detectors, considering the complexity and expensiveness versus quality parameters. These two methods were applied to the analysis of four important indoleamine neurotransmitter analytes (5-hydroxytryptamine, 5-hydroxyindole-3-acetic acid, tryptamine and melatonin) in sea lamprey plasma samples. PMID:22405313

Wang, Huiyong; Walaszczyk, Erin J; Li, Ke; Chung-Davidson, Yu-Wen; Li, Weiming

2012-04-01

118

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

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

Willison, Stuart A

2012-12-28

119

High-Sensitivity Microwave Optics.  

ERIC Educational Resources Information Center

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

Nunn, W. M., Jr.

1981-01-01

120

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

Microsoft Academic Search

We have recently seen the emergence of ultra-performance liquid chromatography (UPLC) coupled to mass spectrometry as an alternative to traditional high-performance liquid chromatography techniques. The strengths of UPLC technology promote the ability to separate and identify drug compounds with significant gains in resolution and sensitivity and marked reductions in the overall time of analysis. As increased throughput is the desire

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

2006-01-01

121

A high sensitivity THz detector  

NASA Astrophysics Data System (ADS)

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.

Su, Bo; Duan, Guoteng

2011-08-01

122

A high sensitivity resonator pressure sensor  

Microsoft Academic Search

We propose a new resonator pressure sensor using shallow shells. The sensor has high sensitivity due to the shallow shell structure. A theoretical analysis is performed using the theory for small fields superposed on finite biasing fields in an elastic body. The analysis shows that shallow shells have a magnifying effect on sensor sensitivity. Sensitivity of a quartz plate thickness-shear

J. S. Yang; X. Zhang

2002-01-01

123

High-sensitivity nanosensors for biomarker detection†  

PubMed Central

High sensitivity nanosensors utilize optical, mechanical, electrical, and magnetic relaxation properties to push detection limits of biomarkers below previously possible concentrations. The unique properties of nanomaterials and nanotechnology are exploited to design biomarker diagnostics. High-sensitivity recognition is achieved by signal and target amplification along with thorough pre-processing of samples. In this tutorial review, we introduce the type of detection signals read by nanosensors to detect extremely small concentrations of biomarkers and provide distinctive examples of high-sensitivity sensors. The use of such high-sensitivity nanosensors can offer earlier detection of disease than currently available to patients and create significant improvements in clinical outcomes. PMID:22187721

Swierczewska, Magdalena; Liu, Gang

2013-01-01

124

High sensitivity radon emanation measurements.  

PubMed

The presented radon detection technique employs miniaturized ultra-low background proportional counters. (222)Rn samples are purified, mixed with a counting gas and filled into a counter using a special glass vacuum line. The absolute sensitivity of the system is estimated to be 40 microBq (20 (222)Rn atoms). For emanation investigations two metal sealed stainless steel vessels and several glass vials are available. Taking into account their blank contributions, measurements at a minimum detectable activity of about 100 microBq can be performed. PMID:19249216

Zuzel, G; Simgen, H

2009-05-01

125

Cryogenic High-Sensitivity Magnetometer  

NASA Technical Reports Server (NTRS)

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

Day, Peter; Chui, Talso; Goodstein, David

2005-01-01

126

High sensitivity cymbal-based accelerometer  

Microsoft Academic Search

A high sensitivity piezoelectric accelerometer has been developed by replacing the conventional piezoelectric rings with a cymbal transducer. The sensitivity of the cymbal-based accelerometers containing cymbal transducers with different endcap thicknesses and different seismic masses has been measured as a function of driving frequency. Due to the high d33' coefficient of the cymbal transducers, the cymbal-based accelerometers have a high

Cheng-Liang Sun; K. H. Lam; S. H. Choy; H. L. W. Chan; X.-Z. Zhao; C. L. Choy

2006-01-01

127

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

PubMed

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

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

2014-10-01

128

High Sensitivity deflection detection of nanowires  

SciTech Connect

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

Sanii, Babak; Ashby, Paul

2009-10-28

129

Competing interactions in highly sensitive ceramics  

NASA Astrophysics Data System (ADS)

Many complex ceramics are used as sensors and actuators because of their high sensitivity to external stimuli, even though ceramics are basically hard materials. The key to extract soft-behavior out of hard materials is the near-equal balance in competing forces. This can be found, for instance, near the phase transition. However, most phase transitions are first order, controlled by the motion of phase boundaries, and do not produce high sensitivity. Second order transition, on the other hand, provides high sensitivity only over a very narrow temperature range close to the transition. We discuss how controlled disorder and localization can produce the desired effect over wider ranges of temperature and amplitude of external stimuli. Examples used are the colossal magnetoresistive (CMR) oxides, piezoelectric oxides, and relaxor ferroelectric oxides, based upon the knowledge of the local atomic structure determined by pulsed neutron and synchrotron x-ray scattering.

Egami, Takeshi

2004-03-01

130

Highly sensitive submillimeter InSb photodetectors  

SciTech Connect

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

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

2008-10-15

131

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

PubMed

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

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

2014-01-01

132

Two highly sensitive microwave cavity spectrometers  

NASA Astrophysics Data System (ADS)

A description is presented for two unconventional highly sensitive spectrometers operating in the decimeter-wave region (90-450 MHz) and millimeter-wave region (90-150 GHz), respectively. In both cases a resonant cavity is used as an absorption cell. Either design combines high sensitivity with high resolution and wide spectral range. The radio frequency spectrometer allows measuring of extremely low absorption quantity 3×10-12 cm-1 in combination with high spectral resolution of order 1 kHz with the radio frequency-microwave double resonance method. The gas cell is a coaxial cavity (Q?103) with a diameter of 40 cm and length about a wavelength. The millimeter-wave spectrometer utilizes an orotron oscillator as the tunable, coherent source of radiation from 90 to 150 GHz. A gas cell is placed into a high quality (Q?104) Fabry-Pérot resonator of the orotron, and the absorption signal is detected by variation of the orotron electron current in the collector circuit. The sensitivity limit of (2-5)×10-10 cm-1 is achieved with Stark modulation as well as source frequency modulation. Some results of successful application of both designs in molecular spectroscopy are presented, and potential use of the millimeter-wave cavity spectrometer as a gas analyzer with a detection limit better than 1 ppm is briefly discussed.

Dumesh, B. S.; Surin, L. A.

1996-10-01

133

High sensitivity neutron detector for Z  

SciTech Connect

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

Ruggles, L.E.; Porter, J.L. Jr.; Simpson, W.W.; Vargas, M.F.; Zagar, D.M.; Hartke, R.; Buersgens, F.; Symes, D.R.; Ditmire, T. [Sandia National Laboratories, Albuquerque, New Mexico 87185-1193 (United States); The University of Texas at Austin, Austin, Texas 78712 (United States)

2004-10-01

134

Highly sensitive catalytic spectrophotometric determination of ruthenium.  

PubMed

A new and highly sensitive catalytic kinetic method (CKM) for the determination of ruthenium(III) has been established based on its catalytic effect on the oxidation of l-phenylalanine (l-Pheala) by KMnO(4) in highly alkaline medium. The reaction has been followed spectrophotometrically by measuring the decrease in the absorbance at 526nm. The proposed CKM is based on the fixed time procedure under optimum reaction conditions. It relies on the linear relationship where the change in the absorbance (DeltaA(t)) versus added Ru(III) amounts in the range of 0.101-2.526ngml(-1) is plotted. Under the optimum conditions, the sensitivity of the proposed method, i.e. the limit of detection corresponding to 5min is 0.08ngml(-1), and decreases with increased time of analysis. The method is featured with good accuracy and reproducibility for ruthenium(III) determination. The ruthenium(III) has also been determined in presence of several interfering and non-interfering cations, anions and polyaminocarboxylates. No foreign ions interfered in the determination ruthenium(III) up to 20-fold higher concentration of foreign ions. In addition to standard solutions analysis, this method was successfully applied for the quantitative determination of ruthenium(III) in drinking water samples. The method is highly sensitive, selective and very stable. A review of recently published catalytic spectrophotometric methods for the determination of ruthenium(III) has also been presented for comparison. PMID:17574906

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

2008-01-01

135

High sensitivity nanoparticle detection using optical microcavities  

PubMed Central

We demonstrate a highly sensitive nanoparticle and virus detection method by using a thermal-stabilized reference interferometer in conjunction with an ultrahigh-Q microcavity. Sensitivity is sufficient to resolve shifts caused by binding of individual nanobeads in solution down to a record radius of 12.5 nm, a size approaching that of single protein molecules. A histogram of wavelength shift versus nanoparticle radius shows that particle size can be inferred from shift maxima. Additionally, the signal-to-noise ratio for detection of Influenza A virus is enhanced to 38?1 from the previously reported 3?1. The method does not use feedback stabilization of the probe laser. It is also observed that the conjunction of particle-induced backscatter and optical-path-induced shifts can be used to enhance detection signal-to-noise. PMID:21444782

Lu, Tao; Lee, Hansuek; Chen, Tong; Herchak, Steven; Kim, Ji-Hun; Fraser, Scott E.; Flagan, Richard C.; Vahala, Kerry

2011-01-01

136

Highly sensitive nanoscale spin-torque diode.  

PubMed

Highly sensitive microwave devices that are operational at room temperature are important for high-speed multiplex telecommunications. Quantum devices such as superconducting bolometers possess high performance but work only at low temperature. On the other hand, semiconductor devices, although enabling high-speed operation at room temperature, have poor signal-to-noise ratios. In this regard, the demonstration of a diode based on spin-torque-induced ferromagnetic resonance between nanomagnets represented a promising development, even though the rectification output was too small for applications (1.4?mV?mW(-1)). Here we show that by applying d.c. bias currents to nanomagnets while precisely controlling their magnetization-potential profiles, a much greater radiofrequency detection sensitivity of 12,000?mV?mW(-1) is achievable at room temperature, exceeding that of semiconductor diode detectors (3,800?mV?mW(-1)). Theoretical analysis reveals essential roles for nonlinear ferromagnetic resonance, which enhances the signal-to-noise ratio even at room temperature as the size of the magnets decreases. PMID:24141450

Miwa, S; Ishibashi, S; Tomita, H; Nozaki, T; Tamura, E; Ando, K; Mizuochi, N; Saruya, T; Kubota, H; Yakushiji, K; Taniguchi, T; Imamura, H; Fukushima, A; Yuasa, S; Suzuki, Y

2014-01-01

137

Highly sensitive catalytic determination of molybdenum.  

PubMed

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

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

2007-02-15

138

Hematology consult: high-sensitivity warfarin genotype.  

PubMed

Warfarin sensitivity genotyping should be considered in patients who require multiple dosing adjustments to maintain a therapeutic international normalized ratio (INR)--patients with a history of bleeding/thrombosis when taking warfarin or patients who are being started on warfarin therapy for the first time. Studies showed that individuals with genetic variants require a longer time to achieve stable dosing, have more INR measurements that are above therapeutic range, and experience more frequent bleeding events than individuals with normal genotypes. This information prompted development of dosing algorithms based on genotypes in an attempt to more accurately predict warfarin dose and avoid such complications. We report herein a patient with an exaggerated response to warfarin, who was subsequently diagnosed with a high-sensitivitywarfarin genotype. Genetic testing for warfarin sensitivity polymorphisms is currently available, and may decrease event rates for bleeding and/orthromboembolismwhen used to guide dosing. Notwithstanding, randomized controlled trials are awaited to determine the true impact of this testing on clinical outcomes and its cost-effectiveness. PMID:24367840

Schwer, Caitlin; Lamana, Samuel; Dasanu, Constantin A

2013-01-01

139

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

PubMed

Mithramycin is a neoplastic antibiotic synthesized by various Streptomyces bacteria. It is under investigation as a chemotherapeutic treatment for a wide variety of cancers. Ongoing and forthcoming clinical trials will require pharmacokinetic analysis of mithramycin in humans, both to see if target concentrations are achieved and to optimize dosing and correlate outcomes (response/toxicity) with pharmacokinetics. Two published methods for mithramycin quantitation exist, but both are immunoassays that lack current bioanalytical standards of selectivity and sensitivity. To provide an upgraded and more widely applicable assay, a UPLC-MS/MS method for quantitation of mithramycin in human plasma was developed. Solid-phase extraction allowed for excellent recoveries (>90%) necessary for high throughput analyses on sensitive instrumentation. However, a ?55% reduction in analyte signal was observed as a result of plasma matrix effects. Mithramycin and the internal standard chromomycin were separated on a Waters Acquity BEH C18 column (2.1×50 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

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

2014-11-01

140

Highly sensitive silicon microreactor for catalyst testing  

SciTech Connect

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

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

2009-12-15

141

Transportable high sensitivity small sample radiometric calorimeter  

SciTech Connect

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.

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

1998-12-31

142

Axitinib sensitization of high Single Dose Radiotherapy  

PubMed Central

Background and purpose Single Dose Radiation Therapy (SDRT) provides remarkably high rates of control even for tumors resistant to fractionated radiotherapy. SDRT tumor control depends on acute acid sphingomyelinase-mediated endothelial cell injury and monoclonal antibodies targeting Vascular Endothelial Cell Growth Factor (VEGF) signaling radiosensitized tumor endothelium when delivered immediately prior to irradiation. Here we evaluate the ability of the oral VEGF receptor inhibitor, axitinib, to sensitize tumor endothelium and increase tumor control with SDRT. Methods and materials Axitinib was added to primary cultured endothelial cells, or administered orally to Sv129/BL6 mice bearing radiosensitive MCA/129 sarcoma or radioresistant B16F1 melanoma flank tumors, followed by SDRT. Endothelial apoptosis was assessed by TUNEL assay or bis-benzamide staining. Mice with irradiated tumors were followed for 90 days to evaluate the impact of axitinib on SDRT tumor control. Results Pre-treatment with axitinib increased acute endothelial cell apoptosis following SDRT in vitro, and in vivo for both MCA/129 and B16F1 tumors. Axitinib correspondingly increased SDRT tumor growth delay and complete response rate (by 40%) for both tumors. Administration precisely 1 h before SDRT was critical for radiosensitization. Conclusions Axitinib radiosensitizes tumor endothelial cells and enhances tumor cure with SDRT, which may permit dose de-escalation and significantly expand the range of clinical indications for SDRT. PMID:24794795

Rao, Shyam S.; Thompson, Chris; Cheng, Jin; Haimovitz-Friedman, Adriana; Powell, Simon N.; Fuks, Zvi; Kolesnick, Richard N.

2014-01-01

143

High sensitivity optical fiber temperature sensor based on the temperature cross-sensitivity feature of RI-sensitive device  

NASA Astrophysics Data System (ADS)

Considerable part of optical fiber refractive index (RI) sensors suffer from the drawback of cross-sensitivity to temperature because of the thermo-optic effect of materials. In this paper, we propose a straightforward method to utilize the temperature cross-sensitivity feature of an optical fiber RI-sensitive device and thus got a high sensitivity temperature sensor. The sensor consists of a single mode fiber-multimode fiber core(MMFC)-single mode fiber structural refractometer encapsulated into a deionized water-filled cylindrical aluminum alloy shell. Benefiting from the larger thermo-optic coefficient difference between water and MMFC compared with the general cladding and core, the wavelength of transmitted spectrum presents enhanced shift when the ambient temperature change and thus get a higher temperature sensitivity. Experimental results show that the enhanced temperature sensitivity is about 358 pm/°C, which is almost 30 times that of the inherent temperature sensitivity.

Sun, Hao; Hu, Manli; Rong, Qiangzhou; Du, Yanying; Yang, Hangzhou; Qiao, Xueguang

2014-07-01

144

A case of high noise sensitivity  

NASA Astrophysics Data System (ADS)

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

Murata, M.; Sakamoto, H.

1995-10-01

145

High sensitivity radiographic NDT using fluorescent screens  

SciTech Connect

Fluorescent Screen exposure previously reserved for thick sections, to shorten long exposures, may now be used for routine radiography. Changes in four areas make this possible: screen technology; specifications; imaging materials not previously available; and technique adjustment. This presentation covers these four areas, the use of fluorescent screens and image quality experimentation that show equivalent sensitivity with conventional techniques. The exposures were shorter and more productive.

Trapp, L.F.; Aman, J.K. [DuPont NDT Systems, Rochester, NY (United States)

1993-12-31

146

Highly sensitive thermal actuators for temperature sensing  

NASA Astrophysics Data System (ADS)

A thermal actuator based on two symmetrical V-shaped beam stacks (also called chevron-type) is presented. Each beam stack consists of 6 beams in parallel. The stacks are coupled facing each other and are slightly shifted along the mirror axis. Both stacks are connected to a lever beam. Due to the thermal expansion of the material, the tip of the lever moves up and downwards perpendicular to the mirror axis. The device is built up of galvanic deposited nickel. Finite element simulations were carried out for design considerations prior to the manufacturing of the device. The simulations were used to optimize the design regarding to the sensitivity and the maximum mechanical stress to be expected. The stress level needs to be lower than the yield strength of the material, to prevent plastic deformation and, therefore, irreversible tip defections. This also limits the overall sensitivity of the design. First results of the device with 400 µm long bent beams show a linear behavior and a sensitivity of 0.5 ?m/K and expectable forces of 66 ?N/K in a temperature range of -30°C up to +40°C.

Steiner, H.; Hortschitz, W.; Stifter, M.; Keplinger, F.; Sauter, T.

2013-05-01

147

Infrared spectroscopic imaging with high spatial resolution and high sensitivity  

NASA Astrophysics Data System (ADS)

Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) is a very sensitive imaging technique for the characterization of molecular films. In order to achieve a spatial resolution close to the diffraction limit a very small pinhole which acts as a point-source has to be used. However, such a small pinhole, the typical diameter would be app. 100 ?m, may reduces dramatically the intensity of the infrared beam. Using a common FTIR spectrometer the spatial resolution is mainly limited by the brilliance of the globar infrared source. Therefore, an improvement in lateral resolution requires a more brilliant light source. The free electron laser (FEL) is such a high brilliant infrared source. The combination of the FEL with the PM-IRRAS imaging system is a new approach to capture spectroscopic images with an excellent spatial resolution close to the diffraction limit. PM-IRRAS images of a self assembly monolayer of phosphonic acid molecules onto a microstructures gold / aluminum oxide surface where characterized. The spectroscopic image exhibits a spatial resolution of app. 5 ?m. An evaluation of characteristic absorbance bands of the phosphate group reveals that phosphonic acid molecules bound with a high degree of orientation but differently at the gold and aluminum oxide surfaces. However, the spectroscopic image reveals also several domains of disordering across the surface. Such domains have a dimension of only few micrometers and can be identified in a high resolved PM-IRRAS image.

Sablinskas, Valdas; Steiner, Gerald; Ceponkus, Justinas; Salzer, Reiner

2008-02-01

148

Highly sensitive magnetite nano clusters for MR cell imaging  

PubMed Central

High sensitivity and suitable sizes are essential for magnetic iron oxide contrast agents for cell imaging. In this study, we have fabricated highly MR sensitive magnetite nanoclusters (MNCs) with tunable sizes. These clusters demonstrate high MR sensitivity. Especially, water suspensions of the MNCs with average size of 63 nm have transverse relaxivity as high as 630 s-1mM-1, which is among the most sensitive iron oxide contrast agents ever reported. Importantly, such MNCs have no adverse effects on cells (RAW 264.7). When used for cell imaging, they demonstrate much higher efficiency and sensitivity than those of SHU555A (Resovist), a commercially available contrast agent, both in vitro and in vivo, with detection limits of 3,000 and 10,000 labeled cells, respectively. The studied MNCs are sensitive for cell imaging and promising for MR cell tracking in clinics. PMID:22462693

2012-01-01

149

Microstructured graphene arrays for highly sensitive flexible tactile sensors.  

PubMed

A highly sensitive tactile sensor is devised by applying microstructured graphene arrays as sensitive layers. The combination of graphene and anisotropic microstructures endows this sensor with an ultra-high sensitivity of -5.53 kPa(-1) , an ultra-fast response time of only 0.2 ms, as well as good reliability, rendering it promising for the application of tactile sensing in artificial skin and human-machine interface. PMID:24895228

Zhu, Bowen; Niu, Zhiqiang; Wang, Hong; Leow, Wan Ru; Wang, Hua; Li, Yuangang; Zheng, Liyan; Wei, Jun; Huo, Fengwei; Chen, Xiaodong

2014-09-24

150

Eugenic metal-free sensitizers with double anchors for high performance dye-sensitized solar cells.  

PubMed

A series of new phenothiazine-based dyes (HL5-HL7) with double acceptors/anchors have been synthesized and used as the sensitizers for highly efficient dye-sensitized solar cells (DSSCs). Among them, the HL7-based cell exhibits the best efficiency of 8.32% exceeding the N719-based cell (7.35%) by ?13%. PMID:25555237

Hung, Wei-I; Liao, You-Ya; Lee, Ting-Hui; Ting, Yu-Chien; Ni, Jen-Shyang; Kao, Wei-Siang; Lin, Jiann T; Wei, Tzu-Chien; Yen, Yung-Sheng

2015-02-01

151

High-sensitivity temperature sensor based on an optoelectronic oscillator.  

PubMed

A high-sensitivity temperature sensor based on an optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. The shift of the oscillation frequency in the OEO is inversely proportional to the variation of temperature. An injection-locking method is employed to set up the initial oscillation frequency of the sensor to overcome the uncertainty of the initial oscillation frequency. The experiment results show that high sensitivity of 43.91 kHz/°C with an accuracy of ±0.12°C is achieved between 20°C and 240°C. The system features high temperature sensitivity, wide dynamic range, and high reliability. PMID:25090345

Zhu, Yanhong; Jin, Xiaofeng; Chi, Hao; Zheng, Shilie; Zhang, Xianmin

2014-08-01

152

Development of a high sensitivity accelerometer for the Mica platform.  

E-print Network

Development of a high sensitivity accelerometer for the Mica platform. RUIZ-SANDOVAL Manuel of the computation to be done locally on the sensor's embedded microprocessor. The Mica Mote platform, along

Spencer Jr., B.F.

153

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

PubMed

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. PMID:24517800

Niu, Zhe; Zhao, Yulong; Tian, Bian

2014-01-01

154

Development of a high-sensitivity radiation detector for chromatography  

Microsoft Academic Search

Radionuclide techniques will be increasingly important for the development of biofuels, since they can both uniquely characterize metabolic pathways and image large model systems. We are investigating the application of nuclear medical imaging tools and techniques to biofuel development, using high-sensitivity chromatographic radiation detectors and compounds radiolabeled with short-lived, cyclotron-produced, positron-emitting isotopes (e.g., 11C). The application of high-sensitivity radiation detectors

J. S. Huber; S. M. Hanrahan; W. W. Moses; S. E. Derenzo; B. W. Reutter; J. P. O'Neil; G. T. Gullberg

2009-01-01

155

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

PubMed

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

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

2013-02-15

156

Infrared spectroscopic imaging with high spatial resolution and high sensitivity  

Microsoft Academic Search

Polarization Modulation Infrared Reflection Absorption Spectroscopy (PM-IRRAS) is a very sensitive imaging technique for the characterization of molecular films. In order to achieve a spatial resolution close to the diffraction limit a very small pinhole which acts as a point-source has to be used. However, such a small pinhole, the typical diameter would be app. 100 mum, may reduces dramatically

Valdas Sablinskas; Gerald Steiner; Justinas Ceponkus; Reiner Salzer

2008-01-01

157

High-Sensitivity Accelerometer Using Multilayer Piezoelectric Ceramics  

Microsoft Academic Search

A high sensitivity accelerometer using multilayer piezoelectric ceramics including internal electrodes has been developed. The sensitivity of this accelerometer is about 900 pC\\/G at the frequency range from 0.01 to 10 Hz. Because the circuit was structed to cancel pyroelectric voltages, the output voltage changes of this accelerometer were decreased to 1\\/10 compared with the case of a noncanceling circuit.

Yasunori Ohtsuki; Yoshiaki Fuda; Tetsuo Yoshida

1993-01-01

158

Highly-Sensitive and Efficient Infrared Absorption Spectroscopy  

E-print Network

Highly-Sensitive and Efficient Infrared Absorption Spectroscopy of Molecular Ions Mike Lindsay Oka diameter inner bore ·Discharge column length ~1 m ·Gas flow rate ~ 200 L/Min ·TRot ~500 K, TVib ~ 1500 K of molecular species High-spatial resolution Measurement of spectral fingerprint Generally applicable Low

Lindsay, C. Michael

159

Pressure sensitive paint suitable to high Knudsen number regime  

NASA Astrophysics Data System (ADS)

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.

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

2006-06-01

160

Stability of the proteasome inhibitor bortezomib in cell based assays determined by ultra-high performance liquid chromatography coupled to tandem mass spectrometry.  

PubMed

Bortezomib represents the first clinically approved proteasome inhibitor for multiple myeloma. Research conducted on its intracellular kinetics in target cells and on possibly related mechanisms of resistance is sparse so far. We therefore developed and validated a highly sensitive ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC/MS/MS) method for bortezomib quantification within cultured myeloma cells and media. Fast gradient UPLC based on a BEH C18 column (1.7 ?m particle size) with aqueous formic acid and acetonitrile as mobile phase. Selective extraction procedures using protein precipitation extraction (PPE) and liquid-liquid extraction (LLE) were established and compared. Extracted bortezomib was quantified by positive electrospray tandem mass spectrometry using deuterated D8-bortezomib as internal standard. The calibrated ranges were 0.5-2500 pg per sample. For LLE, overall accuracies varied between 99.2% and 112% (medium) and 89.9% and 111% (cells), while overall precision ranged from 1.13% to 13.0% (medium) and 2.80% to 12.7% (cells), respectively. Recovery rates (cells/medium) were >77%/>65% for LLE and >89%/63% for PPE. Matrix effects were generally lower for LLE compared to PPE. Regardless of the extraction method, retrievable amounts of bortezomib were considerably reduced after 24h of incubation (0.2, 1, 5, and 25 nM). Revealing greater dependence on the extent of acidification, retrieval of bortezomib can be increased distinctly in acidified solution or acidified culture medium. Thus, particular attention needs to be paid to the occurring bortezomib degradation in neutral culture medium since correct quantification of intracellular bortezomib can only be achieved in relation to the corresponding extracellular concentration. PMID:24780258

Clemens, Jannick; Longo, Magdalena; Seckinger, Anja; Hose, Dirk; Haefeli, Walter Emil; Weiss, Johanna; Burhenne, Jürgen

2014-06-01

161

A sensitive and high dynamic range cw laser power meter.  

PubMed

We report the design of a cost effective, highly sensitive cw laser power meter with a large dynamic range based on a photodiode. The power meter consists of a photodiode, a current to voltage converter circuit, an offset balancing circuit, a microcontroller, an analog to digital converter, reed relays, and an alphanumeric liquid crystal display. The power meter can record absolute laser power levels as low as 1 pW. The dynamic range measured with a cw laser at a wavelength of 532 nm is 8x10(10). The high sensitivity and large dynamic range are achieved by the implementation of an analog background balancing circuit and autoranging. PMID:19123586

Krishnan, S; Bindra, K S; Oak, S M

2008-12-01

162

Analytical Glycobiology at High Sensitivity: Current Approaches and Directions  

PubMed Central

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

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

2013-01-01

163

A high sensitivity position-sensitive detector based on Au-SiO2-Si structure  

NASA Astrophysics Data System (ADS)

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 of the light, suggesting some extra potential for the development of new types of waveguide-like devices.

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

2011-01-01

164

A high sensitivity nanomaterial based SAW humidity sensor  

NASA Astrophysics Data System (ADS)

In this paper, a highly sensitive humidity sensor is reported. The humidity sensor is configured by a 128°YX-LiNbO3 based surface acoustic wave (SAW) resonator whose operating frequency is at 145 MHz. A dual delay line configuration is realized to eliminate external temperature fluctuations. Moreover, for nanostructured materials possessing high surface-to-volume ratio, large penetration depth and fast charge diffusion rate, camphor sulfonic acid doped polyaniline (PANI) nanofibres are synthesized by the interfacial polymerization method and further deposited on the SAW resonator as selective coating to enhance sensitivity. The humidity sensor is used to measure various relative humidities in the range 5-90% at room temperature. Results show that the PANI nanofibre based SAW humidity sensor exhibits excellent sensitivity and short-term repeatability.

Wu, Tsung-Tsong; Chen, Yung-Yu; Chou, Tai-Hsu

2008-04-01

165

A highly conjugated benzimidazole carbene-based ruthenium sensitizer for dye-sensitized solar cells.  

PubMed

A new type of carbene-based ruthenium sensitizer, CB104, with a highly conjugated ancillary ligand, diphenylvinylthiophene-substituted benzimidazolepyridine, was designed and developed for dye-sensitized solar cell applications. The influence of the thiophene antenna on the performance of the cell anchored with CB104 was investigated. Compared with the dye CBTR, the conjugated thiophene in the ancillary ligand of CB104 enhanced the molar extinction coefficient of the intraligand ?-?* transition and the intensity of the lower energy metal-to-ligand charge-transfer band. However, the incident photon-to-current conversion efficiency spectrum of the cell anchored with CB104 (0.15?mM) showed a maximum of 63?% at 420?nm. The cell sensitized with the dye CB104 attained a power conversion efficiency of 7.30?%, which was lower than that of the cell with nonconjugated sensitizer CBTR (8.92?%) under the same fabrication conditions. The variation in the performance of these two dyes demonstrated that elongating the conjugated light-harvesting antenna resulted in the reduction of short-circuit photocurrent density, which might have been due to the aggregation of dye molecules. In the presence of a coabsorbate, chenodeoxycholic acid, the CB104-sensitized cell exhibited an enhanced photocurrent density and achieved a photovoltaic efficiency of 8.36?%. PMID:23832840

Ho, Shih-Yu; Su, Chaochin; Li, Chung-Yen; Prabakaran, Kumaresan; Shen, Ming-Tai; Chen, Ying-Fan; Chang, Wei-Chun; Tingare, Yogesh S; Akula, Suribabu; Tsai, Sheng-Han; Li, Wen-Ren

2013-09-01

166

A novel FBG pressure sensor with high sensitivity  

Microsoft Academic Search

A high-sensitivity fiber Bragg grating (FBG) pressure sensor has been designed and studied. Confining some gas inside a glass cylinder with a close glass piston which can move smoothly along the cylinder, and sticking two ends of a fiber Bragg grating on the outer side of the cylinder and piston respectively. The variation of the external pressure results in the

Shiya He; Shuyang Hu; Dawei Tian; Kuanxin Yu; Qida Zhao; Jinfeng Zhou; Li Wang

2005-01-01

167

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...

168

Highly Sensitive, Mechanically Stable Nanopore Sensors for DNA Analysis  

E-print Network

Highly Sensitive, Mechanically Stable Nanopore Sensors for DNA Analysis By Bala Murali Venkatesan the biophysics governing single-molecule trans- port through solid-state nanopores is of fundamental importance in working toward the goal of DNA detection and genome sequencing using nanopore-based sensors. Even

Bashir, Rashid

169

Photonic Crystal Slot Waveguide Optical Absorption Spectrometer for Highly sensitive  

E-print Network

Photonic Crystal Slot Waveguide Optical Absorption Spectrometer for Highly sensitive Near · With photonic band gaps: "optical insulators" 1-D grating =1-D PhC 2-D PhC =2-D grating 3-D PhC =3-D grating

Texas at Austin, University of

170

A sensitive and high dynamic range cw laser power meter  

Microsoft Academic Search

We report the design of a cost effective, highly sensitive cw laser power meter with a large dynamic range based on a photodiode. The power meter consists of a photodiode, a current to voltage converter circuit, an offset balancing circuit, a microcontroller, an analog to digital converter, reed relays, and an alphanumeric liquid crystal display. The power meter can record

S. Krishnan; K. S. Bindra; S. M. Oak

2008-01-01

171

Instrumentation for high-efficiency, high-sensitivity actinide analysis  

SciTech Connect

This is the final report of a 3-year project. We have developed a high-efficiency thermal ionization source that provides one to two orders of magnitude improvement in sample utilization efficiency in comparison with the traditional filament-type ion source currently used in thermal ionization mass spectrometry. This improved sample utilization efficiency results in a proportional increase in sample throughput and proportional decrease in analysis time. Coupling this source with a quadrupole mass spectrometer results in an instrument system for high-efficiency actinide analysis and other applications. In addition to its high efficiency, the sample used in this source can be much smaller than that in previous tube-type sources. The compact structure of the cavity makes it more applicable to any type of mass spectrometer and the whole instrument is small and transportable.

Olivares, J.; Chamberlin, E.; Murrell, M.; Kahr, M.; Duan, Y.

1996-04-01

172

A high sensitivity inductive sensor for blade tip clearance measurement  

NASA Astrophysics Data System (ADS)

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

Du, Li; Zhu, Xiaoliang; Zhe, Jiang

2014-06-01

173

High-throughput and simultaneous analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry in the positive and negative ionization modes.  

PubMed

In this report, a high-throughput and sensitive method for analysis of eight central-acting muscle relaxants in human plasma by ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) in the positive and negative ionization modes using tolbutamide as internal standard is presented. After pretreatment of a plasma sample by solid-phase extraction with an Oasis HLB cartridge, muscle relaxants were analyzed by UPLC with Acquity UPLC BEH C(18) column and Acquity TQD tandem quadrupole mass spectrometer equipped with an electrospray ionization interface. The calibration curves for muscle relaxants spiked into human plasma equally showed good linearities in the nanogram per milliliter order range. The detection limits (signal-to-noise ratio?=?3) was as low as 0.1-2 ng/mL. The method gave satisfactory recovery rates, accuracy, and precision for quality control samples spiked with muscle relaxants. To further validate the present method, 250 mg of chlorphenesin carbamate was orally administered to a healthy male volunteer, and the concentrations of chlorphenesin carbamate in plasma were measured 0.5, 1, 2, 4, 6, and 8 h after dosing; their concentrations in human plasma were between 0.62 and 2.44 ?g/mL. To our knowledge, this is the first report describing simultaneous analysis of over more than two central-acting muscle relaxants by liquid chromatography-tandem mass spectrometry. This has been realized by the capability of our instrument for simultaneous multiple reaction monitoring of the target compounds in both positive and negative ionization modes. Therefore, the present method seems very useful in forensic and clinical toxicology and pharmacokinetic studies. PMID:21394449

Ogawa, Tadashi; Hattori, Hideki; Kaneko, Rina; Ito, Kenjiro; Iwai, Masae; Mizutani, Yoko; Arinobu, Tetsuya; Ishii, Akira; Seno, Hiroshi

2011-06-01

174

Sensitive high-Tc SQUID magnetometers for unshielded operation  

Microsoft Academic Search

We have developed sensitive highly reliable high-Tc SQUID magnetometers a reproducible SNS junction fabrication process. In order to enable unshielded operation in the earth's field, we have incorporated flux dams into direct-coupled SQUID magnetometers. By using up to four pickup coils in parallel, each with its own flux dam, an effective area of 0.57 mm2 has been achieved on 24

M. S. Dilorio; K. Yang; S. Yoshizumi; S. G. Haupt; D. Haran; R. H. Koch; F. P. Milliken; J. R. Rozen; D. K. Lathrop; S. Kumar

1999-01-01

175

High-sensitivity, high-speed continuous imaging system  

DOEpatents

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.

Watson, Scott A; Bender, III, Howard A

2014-11-18

176

High-sensitivity microfiber strain and force sensors  

NASA Astrophysics Data System (ADS)

A microfiber biconically tapered from a standard optical fiber shows obvious sinusoidal oscillatory transmission spectrum due to the multimode interference, with evident blue-shifted peak wavelength when applying an axial force. Based on this force-induced spectral shift, here we experimentally demonstrate compact microfiber strain and force sensors with low optical power and high sensitivity. With a 1.5-?W probing light, measured sensitivity of a 2.5-?m-diameter microfiber for the strain and elongation sensing are 4.84 pm/?? and 404 pm/?m respectively, with a force detection limit down to 50 ?N.

Li, Wei; Hu, Zhifang; Li, Xiyuan; Fang, Wei; Guo, Xin; Tong, Limin; Lou, Jingyi

2014-03-01

177

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

PubMed Central

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

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

2011-01-01

178

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

PubMed

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

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

2011-01-01

179

High-sensitivity linear piezoresistive transduction for nanomechanical beam resonators  

NASA Astrophysics Data System (ADS)

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.

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

2014-07-01

180

Sensitivity of HAWC to high-mass dark matter annihilations  

NASA Astrophysics Data System (ADS)

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.

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

181

High-sensitivity three-mode optomechanical transducer  

SciTech Connect

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

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

2011-12-15

182

Development of High Sensitivity Nuclear Emulsion and Fine Grained Emulsion  

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

183

Quantum-Dot-Sensitized Solar Cell with Unprecedentedly High Photocurrent  

PubMed Central

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

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

2013-01-01

184

Horizontal film balance having wide range and high sensitivity  

DOEpatents

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.

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

1981-03-05

185

Horizontal film balance having wide range and high sensitivity  

DOEpatents

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.

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

1983-11-08

186

Structural Glycomic Analyses at High Sensitivity: A Decade of Progress  

PubMed Central

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

Alley, William R.; Novotny, Milos V.

2014-01-01

187

Horizontal film balance having wide range and high sensitivity  

DOEpatents

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.

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

1983-01-01

188

High sensitive volumetric imaging of renal microcirculation in vivo using ultrahigh sensitive optical microangiography  

NASA Astrophysics Data System (ADS)

We present a non-invasive, label-free imaging technique called Ultrahigh Sensitive Optical Microangiography (UHSOMAG) for high sensitive volumetric imaging of renal microcirculation. The UHS-OMAG imaging system is based on spectral domain optical coherence tomography (SD-OCT), which uses a 47000 A-line scan rate CCD camera to perform an imaging speed of 150 frames per second that takes only ~7 seconds to acquire a 3D image. The technique, capable of measuring slow blood flow down to 4 um/s, is sensitive enough to image capillary networks, such as peritubular capillaries and glomerulus within renal cortex. We show superior performance of UHS-OMAG in providing depthresolved volumetric images of rich renal microcirculation. We monitored the dynamics of renal microvasculature during renal ischemia and reperfusion. Obvious reduction of renal microvascular density due to renal ischemia was visualized and quantitatively analyzed. This technique can be helpful for the assessment of chronic kidney disease (CKD) which relates to abnormal microvasculature.

Zhi, Zhongwei; Jung, Yeongri; Jia, Yali; An, Lin; Wang, Ruikang K.

2011-03-01

189

Sensitivity to Error Fields in NSTX High Beta Plasmas  

SciTech Connect

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

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

2011-11-07

190

Highly Sensitive Measurements of 222Rn Diffusion and Emanation  

SciTech Connect

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 {approx}30 {mu}Bq. Radon diffusion can be measured at the level of {approx}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 {approx}10-12 g/g 238U-equivalent.

Zuzel, Grzegorz [Max Planck Institute for Nuclear Physics, Saupfercheckweg 1, 69117 Heidelberg (Germany)

2005-09-08

191

Position sensitive detection of neutrons in high radiation background field  

SciTech Connect

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}.

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

192

Piezoelectric rubber films for highly sensitive impact measurement  

NASA Astrophysics Data System (ADS)

We have successfully demonstrated the microfabrication of piezoelectric rubber films and their application in impact measurement. To realize the desired piezoelectricity and stretchability, cellular polydimethylsiloxane (PDMS) structures with micrometer-sized voids are internally implanted with bipolar charges, which function as dipoles and respond promptly to electromechanical stimuli. In the prototype demonstration, 300 µm thick cellular PDMS films are fabricated and internally coated with a thin polytetrafluoroethylene (PTFE) layer to secure the implanted charges. Meanwhile, the top and bottom surfaces of the cellular PDMS films are deposited with stretchable gold electrodes. An electric field up to 35 MV m-1 is applied across the gold electrodes to ionize the air in the voids and to implant charges on the inner surfaces. The resulting composite structures behave like rubber (with an elastic modulus of about 300 kPa) and show strong piezoelectricity (with a piezoelectric coefficient d33 higher than 1000 pC N-1). While integrated with a wide bandwidth and large dynamic-range charge amplifier, highly sensitive impact measurement (with a stress sensitivity of about 10 mV Pa-1) is demonstrated. As such, the demonstrated piezoelectric rubber films could potentially serve as a sensitive electromechanical material for low-frequency stimuli, and fulfill the needs of a variety of physiological monitoring and wearable electronics applications.

Wang, Jhih-Jhe; Tsai, Jui-Wei; Su, Yu-Chuan

2013-07-01

193

Interface engineering of a highly sensitive solution processed organic photodiode.  

PubMed

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

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

2014-09-14

194

Highly sensitive magnetic field sensor and its application  

NASA Astrophysics Data System (ADS)

A pulse induction type magnetic field sensor using an amorphous ribbon as sensing material is described. Its operation principle is based on the dependency of the magnetic properties of the ribbon on ambient magnetic field. Because of the minimal use of active elements simple structure actuate sensitivity (as high as 14V/mT) and good thermostability (as small as O. OO8pT/C) this kind of magnetic field sensor consisting of pulse current sources coils with an amorphous core and induction voltage detectors is successfully used in monitoring the core mandrel of a cold rolling mill for seamless steel pipes. 1

Zhao, Ying-Jun; Yang, Ke-Chong; Yang, Shuzi; Zhen, Jun

1993-09-01

195

Highly sensitive millimeter-wave spectrometer based on an orotron  

NASA Astrophysics Data System (ADS)

The design and operation of a gas millimeter-wave spectrometer based on a tunable generator orotron are presented. The absorption cell occupies a part of the high quality (Q approximately equals 104) orotron Fabry-Perot cavity. The limit of sensitivity (gamma) min approximately equals (3- 5)X 10-10 cm-1 has been achieved with source frequency modulation at the output band of a receiver of 1 Hz. The narrow spectral width of the orotron radiation (10 - 15 kHz without locking) provides the Doppler resolution of spectral lines.

Dumesh, B. S.; Gorbatenkov, V. D.; Kostromin, V. P.; Rusin, F. S.; Surin, L. A.

1994-01-01

196

High Sensitivity Torsion Balance Tests for LISA Proof Mass Modeling  

E-print Network

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.

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

2007-02-08

197

High sensitivity charge amplifier for ion beam uniformity monitor  

DOEpatents

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

Johnson, Gary W. (Livermore, CA)

2001-01-01

198

Highly sensitive detection of cocaine using a piezoelectric immunosensor  

Microsoft Academic Search

This paper describes the development of a highly sensitive competitive immunoassay with the piezoelectric sensor. The immobilized derivative of cocaine was benzoylecgonine-1,8-diamino-3,4-dioxaoctane (BZE-DADOO). For the immobilization of BZE-DADOO, the conjugate BZE-DADOO with 11-mercaptomonoundecanoic acid (MUA) was synthesized via 2-(5-norbornen-2,3-dicarboximide)-1,1,3,3-tetramethyluronium-tetrafluoroborate (TNTU), followed by the creation of the conjugate monolayer on the piezosensor electrodes. For the optimization of the competitive assay we

Jan Halámek; Alexander Makower; Petr Skládal; Frieder W Scheller

2002-01-01

199

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

PubMed

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

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

2014-06-01

200

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

NASA Astrophysics Data System (ADS)

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.

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

2015-01-01

201

Highly sensitive reduced graphene oxide microelectrode array sensor.  

PubMed

Reduced graphene oxide (rGO) has been fabricated into a microelectrode array (MEA) using a modified nanoimprint lithography (NIL) technique. Through a modified NIL process, the rGO MEA was fabricated by a self-alignment of conducting Indium Tin Oxide (ITO) and rGO layer without etching of the rGO layer. The rGO MEA consists of an array of 10?m circular disks and microelectrode signature has been found at a pitch spacing of 60?m. The rGO MEA shows a sensitivity of 1.91nA?m(-1) to dopamine (DA) without the use of mediators or functionalization of the reduced graphene oxide (rGO) active layer. The performance of rGO MEA remains stable when tested under highly resistive media using a continuous flow set up, as well as when subjecting it to mechanical stress. The successful demonstration of NIL for fabricating rGO microelectrodes on flexible substrate presents a route for the large scale fabrication of highly sensitive, flexible and thin biosensing platform. PMID:25461168

Ng, Andrew M H; Kenry; Teck Lim, Chwee; Low, Hong Yee; Loh, Kian Ping

2014-10-23

202

High Sensitivity, Low Volume Method to Determine Dissolved Phosphorus  

NASA Astrophysics Data System (ADS)

A high sensitivity, low volume method was developed to determine nanomolar concentrations of soluble reactive phosphorus (SRP) using reverse phase HPLC. The technique in determining SRP involved using methods from Strickland and Parsons, 1972 and Karl and Tien, 1992. Various techniques for improving blanks and sensitivity will be discussed. The method was applied to seawater and freshwater samples taken from the estuarine Nueces Delta system, Texas, two sites in the Gulf of Mexico, and within two upland (2400 m) forest catchments in the Peruvian Andes. One catchment was partially deforested within the last 3 years, while the other has remained untouched. Samples in the Gulf of Mexico were taken at a series of coastal and open water stations at various depths. Samples in each of the two upland forest catchments in Peru were obtained at 33.3 m distance intervals along a 100 m reach. Samples were taken in the Nueces River, Texas upland from a marsh estuary and from high and low regions of the marsh. Comparisons are made between the forest catchment sites in addition to comparisons made in the Nueces marsh estuary/river system. Depth profiles of SRP in the Gulf of Mexico are established. Future studies should be conducted to investigate phosphate in sediment pore waters. This method has many potential applications, is scalable across a wide range of sample volumes, and can be automated.

Haberer, J. L.; Brandes, J. A.

2001-12-01

203

Sturdy Positioning with High Sensitivity GPS Sensors Under Adverse Conditions  

PubMed Central

High sensitivity GPS receivers have extended the use of GNSS navigation to environments which were previously deemed unsuitable for satellite signal reception. Under adverse conditions the signals become attenuated and reflected. High sensitivity receivers achieve signal reception by using a large number of correlators and an extended integration time. Processing the observation data in dynamic and rapidly changing conditions requires a careful and consistent treatment. Code-based autonomous solutions can cause major errors in the estimated position, due primarily to multipath effects. A custom procedure of autonomous GPS positioning has been developed, boosting the positioning performance through appropriate processing of code and Doppler observations. Besides the common positioning procedures, robust estimation methods have been used to minimise the effects of gross observation errors. In normal conditions, differential GNSS yields good results, however, under adverse conditions, it fails to improve significantly the receiver’s position. Therefore, a so-called conditional DGPS has been developed which determines the position differentially by using data from the strong signals only. These custom-developed procedures have been tested in different conditions in static and kinematic cases and the results have been compared to those processed by the receiver. PMID:22163657

Trajkovski, Klemen Kozmus; Sterle, Oskar; Stopar, Bojan

2010-01-01

204

Sensitivity study of reliable, high-throughput resolution metricsfor photoresists  

SciTech Connect

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

Anderson, Christopher N.; Naulleau, Patrick P.

2007-07-30

205

Highly sensitive detection of urinary cadmium to assess personal exposure.  

PubMed

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(-1) cm(-2)) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the U.S. National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25-1 ppb cadmium. PMID:23561905

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

2013-04-22

206

Highly Sensitive Detection of Urinary Cadmium to Assess Personal Exposure  

PubMed Central

A series of Boron-Doped Diamond (BDD) ultramicroelectrode arrays were fabricated and investigated for their performance as electrochemical sensors to detect trace level metals such as cadmium. The steady-state diffusion behavior of these sensors was validated using cyclic voltammetry followed by electrochemical detection of cadmium in water and in human urine to demonstrate high sensitivity (>200 ?A/ppb/cm2) and low background current (<4 nA). When an array of ultramicroelectrodes was positioned with optimal spacing, these BDD sensors showed a sigmoidal diffusion behavior. They also demonstrated high accuracy with linear dose dependence for quantification of cadmium in a certified reference river water sample from the National Institute of Standards and Technology (NIST) as well as in a human urine sample spiked with 0.25–1 ppb cadmium. PMID:23561905

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

2013-01-01

207

Correcting systematic errors in high-sensitivity deuteron polarization measurements  

NASA Astrophysics Data System (ADS)

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

Brantjes, N. P. M.; Dzordzhadze, V.; Gebel, R.; Gonnella, F.; Gray, F. E.; van der Hoek, D. J.; Imig, A.; Kruithof, W. L.; Lazarus, D. M.; Lehrach, A.; Lorentz, B.; Messi, R.; Moricciani, D.; Morse, W. M.; Noid, G. A.; Onderwater, C. J. G.; Özben, C. S.; Prasuhn, D.; Levi Sandri, P.; Semertzidis, Y. K.; da Silva e Silva, M.; Stephenson, E. J.; Stockhorst, H.; Venanzoni, G.; Versolato, O. O.

2012-02-01

208

Design of a charge sensitive preamplifier on high resistivity silicon  

SciTech Connect

A low noise, fast charge sensitive preamplifier was designed on high resistivity, detector grade silicon. It is built at the surface of a fully depleted region of n-type silicon. This allows the preamplifier to be placed very close to a detector anode. The preamplifier uses the classical input cascode configuration with a capacitor and a high value resistor in the feedback loop. The output stage of the preamplifier can drive a load up to 20pF. The power dissipation of the preamplifier is 13mW. The amplifying elements are ''Single Sided Gate JFETs'' developed especially for this application. Preamplifiers connected to a low capacitance anode of a drift type detector should achieve a rise time of 20ns and have an equivalent noise charge (ENC), after a suitable shaping, of less than 50 electrons. This performance translates to a position resolution better than 3..mu..m for silicon drift detectors. 6 refs., 9 figs.

Radeka, V.; Rehak, P.; Rescia, S.; Gatti, E.; Longoni, A.; Sampietro, M.; Holl, P.; Strueder, L.; Kemmer, J.

1987-01-01

209

Sensitivity of urban hydrodynamic modelling to high resolution radar rainfall  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

210

High-Sensitivity Temperature-Independent Silicon Photonic Microfluidic Biosensors  

NASA Astrophysics Data System (ADS)

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.

Kim, Kangbaek

211

A wide bandwidth, high linearity hybrid charge-sensitive preamplifier for high-capacitance silicon detectors  

Microsoft Academic Search

A new hybrid charge-sensitive preamplifier with a sensitivity of 5 mV\\/MeV has been specifically designed to operate in conjunction with high-capacitance silicon detectors. The shape of the leading edge of its impulse response keeps fast (20 ns) and unchanged over the full output voltage swing (7 V), as is required in nuclear-physics experiments in which Pulse-Shape Analysis is used for

Roberto Bassini; Ciro Boiano; Angelo Pagano; Alberto Pullia

2003-01-01

212

Sensitivity of once-shocked, weathered high explosives  

SciTech Connect

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.

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

1998-07-01

213

Highly sensitive flow-injection chemiluminescence determination of pyrogallol compounds  

NASA Astrophysics Data System (ADS)

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

Kanwal, Shamsa; Fu, Xiaohong; Su, Xingguang

2009-12-01

214

Highly sensitive detection of cocaine using a piezoelectric immunosensor.  

PubMed

This paper describes the development of a highly sensitive competitive immunoassay with the piezoelectric sensor. The immobilized derivative of cocaine was benzoylecgonine-1,8-diamino-3,4-dioxaoctane (BZE-DADOO). For the immobilization of BZE-DADOO, the conjugate BZE-DADOO with 11-mercaptomonoundecanoic acid (MUA) was synthesized via 2-(5-norbornen-2,3-dicarboximide)-1,1,3,3-tetramethyluronium-tetrafluoroborate (TNTU), followed by the creation of the conjugate monolayer on the piezosensor electrodes. For the optimization of the competitive assay we used electrodes with rough or smooth gold areas and for the interaction with immobilized antigen different anti-cocaine sheep polyclonal (pAb, either whole IgG or Fab fragment) and mouse monoclonal (mAb, whole IgG) antibodies. The assay of cocaine developed achieved a detection limit (LOD) of 100 pmol/l (34 ng/l) using the sheep antibody (IgG) and piezoelectric sensors with a smooth gold surface. The total time of one analysis was 15 min and the measuring area of the sensor could be used more than 40 times without losing its sensitivity. PMID:12392954

Halámek, Jan; Makower, Alexander; Skládal, Petr; Scheller, Frieder W

2002-12-01

215

High-throughput antibody screening using high-sensitivity microplate cytometry  

E-print Network

High-throughput antibody screening using high- sensitivity microplate cytometry The increased focus, particularly cell-based methods.TTP LabTech's Mirrorball® offers equivalent data with minimal change exponentially, and they now have a major role in the treatment of a variety of disease states, including cancer

Cai, Long

216

Highly sensitive biological sensor based on photonic crystal fiber  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

217

Versatile, high-sensitivity faraday cup array for ion implanters  

DOEpatents

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

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

2003-01-01

218

Highly sensitive hot electron bolometer based on disordered graphene  

PubMed Central

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

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

2013-01-01

219

Radiation noise in a high sensitivity star sensor  

NASA Technical Reports Server (NTRS)

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

Parkinson, J. B.; Gordon, E.

1972-01-01

220

Highly sensitive and selective catalytic determination of formaldehyde and acetaldehyde.  

PubMed

A highly sensitive, simple and selective kinetic method was developed for the determination of ultra-trace levels of formaldehyde and acetaldehyde based on their catalytic effect on the oxidation of N,N-diethyl-p-phenylenediamine (DPD) with hydrogen peroxide. The reaction was monitored spectrophotometrically by tracing the formation of the red-colored oxidized product of DPD at 510nm, within 30s of mixing the reagents. The optimum reaction conditions were: 20mmolL(-1) DPD, 250mmolL(-1) H(2)O(2), 150mmolL(-1) phosphate, 150mmolL(-1) citrate and pH 6.60+/-0.05 at 25 degrees C. Following the recommended procedure, formaldehyde and acetaldehyde could be determined with linear calibration graphs up to 0.50 and 1.4microg mL(-1) and detection limits, based on the 3S(b)-criterion, of 0.015 and 0.035microg mL(-1), respectively. In addition, analytical data for other 10 aldehydes were also presented. The high sensitivity and selectivity of the proposed method allowed its successful application to rain water, mainstream smoke (MSS) and disposed tips of smoked cigarettes (DTSC). A sample aliquot was directly analyzed for its total water-soluble aldehyde content. A second sample aliquot was heated at 80 degrees C for 10min to expel acetaldehyde and the aliquot was analyzed for its content of other water-soluble aldehydes (expressed as formaldehyde equivalent), and acetaldehyde was determined by difference. The analytical results were in excellent agreements with those obtained following the standard HPLC method based on pre-column derivatization with 2,4-dinitrophenylhydrazine. Moreover, published catalytic-spectrophotometric methods for the determination of aldehydes were reviewed. PMID:18371678

Mohamed, Ashraf A; Mubarak, Ahmed T; Marestani, Zakaria M H; Fawy, Khaled F

2008-01-15

221

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

NASA Astrophysics Data System (ADS)

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.

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

2014-12-01

222

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

E-print Network

of the composites is highly sensitive to strain with a pressure sensitivity of up to 8%/Pa for the whiskers, which is >10Ã? higher than all previously reported capacitive or resistive pressure sensors. It is notable. In essence, an e-whisker device consists of a highly sensitive tactile sensor that is mounted on a high

Javey, Ali

223

Graphene nanomesh as highly sensitive chemiresistor gas sensor.  

PubMed

Graphene is a one atom thick carbon allotrope with all surface atoms that has attracted significant attention as a promising material as the conduction channel of a field-effect transistor and chemical field-effect transistor sensors. However, the zero bandgap of semimetal graphene still limits its application for these devices. In this work, ethanol-chemical vapor deposition (CVD) of a grown p-type semiconducting large-area monolayer graphene film was patterned into a nanomesh by the combination of nanosphere lithography and reactive ion etching and evaluated as a field-effect transistor and chemiresistor gas sensors. The resulting neck-width of the synthesized nanomesh was about ?20 nm and was comprised of the gap between polystyrene (PS) spheres that was formed during the reactive ion etching (RIE) process. The neck-width and the periodicities of the graphene nanomesh (GNM) could be easily controlled depending on the duration/power of the RIE and the size of the PS nanospheres. The fabricated GNM transistor device exhibited promising electronic properties featuring a high drive current and an I(ON)/I(OFF) ratio of about 6, significantly higher than its film counterpart. Similarly, when applied as a chemiresistor gas sensor at room temperature, the graphene nanomesh sensor showed excellent sensitivity toward NO(2) and NH(3), significantly higher than their film counterparts. The ethanol-based graphene nanomesh sensors exhibited sensitivities of about 4.32%/ppm in NO(2) and 0.71%/ppm in NH(3) with limits of detection of 15 and 160 ppb, respectively. Our demonstrated studies on controlling the neck width of the nanomesh would lead to further improvement of graphene-based transistors and sensors. PMID:22931286

Paul, Rajat Kanti; Badhulika, Sushmee; Saucedo, Nuvia M; Mulchandani, Ashok

2012-10-01

224

High sensitivity mapping of Ti distributions in Hadean zircons  

NASA Astrophysics Data System (ADS)

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.

Harrison, T. Mark; Schmitt, Axel K.

2007-09-01

225

High-sensitivity receiver for infrared laser communications.  

NASA Technical Reports Server (NTRS)

Description of a high-sensitivity wide-bandwidth 10.6-micron heterodyne receiver for space and ground operational use. The receiver includes a cooled HgCdTe infrared mixer diode, a conical scanner for spatial tracking, an acquisition channel for spatial search and station alignment, and an automatic frequency-control channel to maintain a fixed laser frequency offset. The infrared mixer is designed to provide nearly quantum-noise-limited operation over an extended range of mixer temperature, bias voltage, and intermediate frequency. The resultant experimental receiver has a measured noise equivalent power of less than 10 to the minus 19th W/Hz over the 15- to 40-MHz i.f. band for mixer temperatures from 85 to 115 K, and less than 2 x 10 to the minus 19th W/Hz up to 140 K. Mixer 3-dB cutoff frequencies as high as 420 MHz were measured at a mixer temperature of 125 K. An analysis and engineering equations are given for receiver noise components, noise equivalent power, available mixer conversion gain, mixer transducer gain, and quantum-noise factor in terms of such factors as mixer parameters, quantum efficiency, mixer temperature, dynamic conductance, bias voltage, local oscillator power, and i.f. amplifier characteristics.

Peyton, B. J.; Dinardo, A. J.; Kanischak, G. M.; Lange, R. A.; Sard, E. W.; Arams, F. R.

1972-01-01

226

High olfactory sensitivity for dimethyl sulphide in harbour seals.  

PubMed

Productive areas are patchily distributed at sea and represent important feeding grounds for many marine organisms. Although pinnipeds are known to travel on direct routes and return regularly to particular feeding sites, the environmental information seals use to perform this navigation is as yet unknown. As atmospheric dimethyl sulphide (DMS) has been demonstrated to be a reliable indicator for profitable foraging areas, we tested seals for their ability to smell DMS at concentrations typical for the marine environment. Using a go/no-go response paradigm we determined the DMS detection threshold in two harbour seals (Phoca vitulina vitulina). DMS stimuli from 8.05 x 108 to 8 pmol (DMS)m(-3)(air) were tested against a control stimulus using a custom-made olfactometer. DMS-thresholds determined for both seals (20 and 13 pmol m(-3)) indicate that seals can detect ambient concentrations associated with high primary productivity, e.g. in the North Atlantic. Thus, seals possess an extraordinarily high olfactory sensitivity for DMS, which could provide a sensory basis for identifying or orienting to profitable foraging grounds. PMID:17148339

Kowalewsky, Sylvia; Dambach, Martin; Mauck, Björn; Dehnhardt, Guido

2006-03-22

227

High sensitivity dynamic spectral search for flare star radio  

NASA Technical Reports Server (NTRS)

We observed ten well-known flare stars with the Arcibo radio telescope at 1.4 GHz and 5 GHz, using a special observing technique to discriminate between real flares and radio freqeuncy interference. With a high sensitivity of 5.5 K/Jy at 1.4 GHz when averaged over a 50 MHz band, we are able to recognize flux enhancements as weak as approximately 6 mJy above the sky background variations. In about 85 hours of observation, about a dozen bursts were detected, only from AD Leo. All had flux densities lower than 70 mJy, which probably explains their lack of fine structures (except for the strongest one), such as were reported in the literature for stronger flares. Half of the bursts that we recorded are 100% circularly polarized, and half are not circularly polarized. Our results are a first attempt of reliable statistics on dMe flare rates at 1.4 GHz. The high brightness temperatures we infer for the observed bursts are interpreted in terms of coherent emission processes, either the cyclotron maser instability or plasma radiation. Efficiencies are comparable to those of solar or planetary radio emissions in the case of the cyclotron maser, and higher than the solar efficiency in the case of plasma radiation, with the caveat that there are great uncertainties in the coronal model and the source size.

Abada-Simon, M.; Lecacheux, A.; Louarn, P.; Dulk, G. A.; Belkora, L.; Bookbinder, J. A.; Rosolen, C.

1994-01-01

228

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

Microsoft Academic Search

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

Makoto NAKANO; Toshikazu TAKEDA; Hideki TAKANO

1987-01-01

229

Highly sensitive and multiplexed platforms for allergy diagnostics  

NASA Astrophysics Data System (ADS)

Allergy is a disorder of the immune system caused by an immune response to otherwise harmless environmental allergens. Currently 20% of the US population is allergic and 90% of pediatric patients and 60% of adult patients with asthma have allergies. These percentages have increased by 18.5% in the past decade, with predicted similar trends for the future. Here we design sensitive, multiplexed platforms to detect allergen-specific IgE using the Interferometric Reflectance Imaging Sensor (IRIS) for various clinical settings. A microarray platform for allergy diagnosis allows for testing of specific IgE sensitivity to a multitude of allergens, while requiring only small volumes of patient blood sample. However, conventional fluorescent microarray technology is limited by i) the variation of probe immobilization, which hinders the ability to make quantitative, assertive, and statistically relevant conclusions necessary in immunodiagnostics and ii) the use of fluorophore labels, which is not suitable for some clinical applications due to the tendency of fluorophores to stick to blood particulates and require daily calibration methods. This calibrated fluorescence enhancement (CaFE) method integrates the low magnification modality of IRIS with enhanced fluorescence sensing in order to directly correlate immobilized probe (major allergens) density to allergen-specific IgE in patient serum. However, this platform only operates in processed serum samples, which is not ideal for point of care testing. Thus, a high magnification modality of IRIS was adapted as an alternative allergy diagnostic platform to automatically discriminate and size single nanoparticles bound to specific IgE in unprocessed, characterized human blood and serum samples. These features make IRIS an ideal candidate for clinical and diagnostic applications, such a POC testing. The high magnification (nanoparticle counting) modality in conjunction with low magnification of IRIS in a combined instrument offers four significant advantages compared to existing sensing technologies: IRIS i) corrects for any variation in probe immobilization, ii) detects proteins from attomolar to nanomolar concentrations in unprocessed biological samples, iii) unambiguously discriminates nanoparticles tags on a robust and physically large sensor area, iv) detects protein targets with conjugated nanoparticle tags (~40nm diameter), which minimally affect assay kinetics compared to conventional microparticle tagging methods, and v) utilizes components that make the instrument inexpensive, robust, and portable. This platform was successfully validated on patient serum and whole blood samples with documented allergy profiles (ImmunoCAPRTM, ThermoFisher Scientific).

Monroe, Margo R.

230

Highly birefringent microstructured fibers with enhanced sensitivity to hydrostatic pressure.  

PubMed

We designed, manufactured and characterized two birefringent microstructured fibers that feature a 5-fold increase in polarimetric sensitivity to hydrostatic pressure compared to the earlier reported values for microstructured fibers. We demonstrate a good agreement between the finite element simulations and the experimental values for the polarimetric sensitivity to pressure and to temperature. The sensitivity to hydrostatic pressure has a negative sign and exceeds -43 rad/MPa x m at 1.55 microm for both fibers. In combination with the very low sensitivity to temperature, this makes our fibers the candidates of choice for the development of microstructured fiber based hydrostatic pressure measurement systems. PMID:20639996

Martynkien, Tadeusz; Statkiewicz-Barabach, Gabriela; Olszewski, Jacek; Wojcik, Jan; Mergo, Pawe?; Geernaert, Thomas; Sonnenfeld, Camille; Anuszkiewicz, Alicja; Szczurowski, Marcin K; Tarnowski, Karol; Makara, Mariusz; Skorupski, Krzysztof; Klimek, Jacek; Poturaj, Krzysztof; Urbanczyk, Waclaw; Nasilowski, Tomasz; Berghmans, Francis; Thienpont, Hugo

2010-07-01

231

Highly-sensitive and high-resolution all-fiber three-dimensional measurement system  

Microsoft Academic Search

A practical all-fiber three-dimensional measurement system is demonstrated with an incoherent interferometer at the eye-safe wavelength of 1.55 mum. The sensitivity and axial resolution are as high as 102 dB and 1.4 mum from a few meters' distance, respectively. A rotating scanner is developed for axial scanning, and a wide longitudinal scanning range of 54 mm is demonstrated. The high

Takefumi Ohta; Norihiko Nishizawa; Tetsuya Ozawa; Kazuyoshi Itoh

2008-01-01

232

Highly sensitive spectrofluorimetric determination of ephedrine hydrochloride in pharmaceutical preparations.  

PubMed

A sensitive and specific spectrofluorimetry method was developed and validated for the quantification of ephedrine (EP) in pharmaceutical preparations. The method is based on the fluorescent enhancing reaction of EP with 7-chloro-4-nitrobenzofurazan (NBD-C1; derivatization reagent), in borate buffer of pH 9 to yield a yellow, fluorescent product. Under these experimental conditions, the derivatized product of EP had excitation and emission wavelength maxima at 458 and 516 nm, respectively. The linear range of this method was 20-2500 ng/mL. The detection limit was 7.3 ng/mL EP. Intra- and interday precisions of the assay at 3 concentrations within this range were 0.037-1.77%. The low relative standard deviation values indicate good precision, and high recovery values indicate excellent accuracy of the method. The proposed method was applied to the determination of the examined drugs in pharmaceutical formulations, and the results indicate that the method is equally as accurate, precise, and reproducible as the official method. PMID:17042174

Ulu, Sevgi Tatar

2006-01-01

233

Improvement of sensitivity in high-resolution Rutherford backscattering spectroscopy  

SciTech Connect

The sensitivity (limit of detection) of high-resolution Rutherford backscattering spectroscopy (HRBS) is mainly determined by the background noise of the spectrometer. There are two major origins of the background noise in HRBS, one is the stray ions scattered from the inner wall of the vacuum chamber of the spectrometer and the other is the dark noise of the microchannel plate (MCP) detector which is commonly used as a focal plane detector of the spectrometer in HRBS. In order to reject the stray ions, several barriers are installed inside the spectrometer and a thin Mylar foil is mounted in front of the detector. The dark noise of the MCP detector is rejected by the coincidence measurement with the secondary electrons emitted from the Mylar foil upon the ion passage. After these improvements, the background noise is reduced by a factor of 200 at a maximum. The detection limit can be improved down to 10 ppm for As in Si at a measurement time of 1 h under ideal conditions.

Hashimoto, H.; Nakajima, K.; Suzuki, M.; Kimura, K. [Department of Micro Engineering, Kyoto University, Kyoto 606-8501 (Japan); Sasakawa, K. [Department of Micro Engineering, Kyoto University, Kyoto 606-8501 (Japan); Kobelco Research Institute, Inc., Takatsukadai 1-5-5, Nishi-ku, Kobe 651-2271 (Japan)

2011-06-15

234

Sensitivity study of high eccentricity orbits for Mars gravity recovery  

NASA Astrophysics Data System (ADS)

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.

He, Zhi-Zhou; Huang, Cheng-Li

2015-01-01

235

Sensitive Radio Observations of High Redshift Dusty QSOs  

E-print Network

We present sensitive radio continuum imaging at 1.4 GHz and 4.9 GHz of seven high redshift QSOs selected for having a 240 GHz continuum detection, which is thought to be thermal dust emission. We detect radio continuum emission from four of the sources: BRI 0952-0115, BR 1202-0725, LBQS 1230+1627B, and BRI 1335-0417. The radio source in BR 1202-0725 is resolved into two components, coincident with the double mm and CO sources. We compare the results at 1.4 GHz and 240 GHz to empirical and semi-analytic spectral models based on star forming galaxies at low redshift. The radio-to-submm spectral energy distribution for BR 1202-0725, LBQS 1230+1627B, and BRI 1335-0417 are consistent with that expected for a massive starburst galaxy, with implied massive star formation rates of order 1000 solar masses per year (without correcting for possible amplification by gravitational lensing). The radio-to-submm spectral energy distribution for BRI 0952-0115 suggests a low-luminosity radio jet source driven by the AGN.

M. S. Yun; C. L. Carilli; R. Kawabe; Y. Tutui; K. Kohno; K. Ohta

1999-09-21

236

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

PubMed

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

Haapala, Markus; Suominen, Tina; Kostiainen, Risto

2013-06-18

237

High sensitivity GEM experiment on 2? decay of 76Ge  

NASA Astrophysics Data System (ADS)

The GEM project is designed for the next-generation 2? decay experiments with 76Ge. One ton of `naked' HP Ge detectors (natural at the first GEM-I phase and enriched in 76Ge to 86% at the second GEM-II stage) are operating in super-high-purity liquid nitrogen contained in a Cu vacuum cryostat (sphere of diameter 5 m). The latter is placed in the water shield (of dimensions 11×11 m2). Monte Carlo simulation evidently shows that the sensitivity of the experiment (in terms of the T1/2 limit for 0?2? decay) is ?1027 yr with natural HP Ge crystals and ?1028 yr with enriched ones. These bounds correspond to the restrictions on the neutrino mass m??0.05 eV and m??0.015 eV with natural and enriched detectors, respectively. Besides, the GEM-I set-up could advance the current best limits on the existence of neutralinos - as dark matter candidates - by three orders of magnitude, and at the same time would be able to identify unambiguously the dark matter signal by detection of its seasonal modulation.

Zdesenko, Yu G.; Ponkratenko, O. A.; Tretyak, V. I.

2001-10-01

238

[High-sensitivity troponin assay: biochemistry and clinical application].  

PubMed

Cardiac troponin is the marker of choice for the diagnosis of acute coronary syndrome. Its introduction in clinical practice consistently improved both sensibility and specificity as compared with other biomarkers, as creatin-chinase MB. However traditional troponin assays show some limits: the relatively long time elapsing between the onset of ischemia and the increase in serum concentration, and the difficulty in distinguishing ischemic from non ischemic damage. An earlier diagnosis could be obtained by adopting new high sensitivity troponin assays, with a coefficient of variation ?10% at the 99° percentile of a reference healthy population, and capable of detecting circulating troponin in the most healty subjects. The difficulty in distinguishing ischemic from non ischemic harm can be overcome considering that only a rising and falling pattern can be attributed to ischemic harm. Further studies are needed to evaluate the prognostic role of low circulating troponin levels in healthy subjects and for properly fixing cut off values. Indeed biomarker increase has always to be considered in the specific clinical context. PMID:21483403

Gustapane, M; Biasillo, G; Della Bona, R; Biasucci, L M

2011-04-01

239

Hi-net: High sensitivity seismograph network, Japan  

NASA Astrophysics Data System (ADS)

The high sensitivity seismograph network in Japan (Hi-net), composed of around 600 seismic stations, is a part of the project made by ‘The Headquarter for Earthquake Research Promotion’ after 1995 Hyogoken-nanbu Earthquake and has been constructed and operated by National Research Institute for Earth Science and Disaster Prevention (NIED). Seismic stations are distributed homogeneously covering whole Japan Islands with an average spacing of 20 30 km. Three-component short period velocity seismometers are installed at the bottom of boreholes with depth of 100 m or deeper. Seismic data are digitized by 24-bit A/D converter and decimated to 27bit data with the sampling frequency of 100Hz. Stations are connected to the Hi-net data center, NIED in Tsukuba by a frame relay network service. TCP/IP and SNMP are used for data transmission and network management, respectively. The data are continuously transmitted to the data center and local offices of Japan Meteorological Agency for routine monitoring of seismic activity. The data receiving, monitoring, processing, and archiving system is controlled by a database management system in the data center. Event detection, phase picking, hypocentral determination, spectra analyses, and extracting waveform parameters are processed automatically. Event information and continuous waveform data are available through the world-wide-web.

Obara, Kazushige

240

High sensitivity metamaterial based bi-material terahertz sensor  

NASA Astrophysics Data System (ADS)

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.

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

2013-03-01

241

High sensitivity Moire interferometry with phase shifting at nano resolution  

NASA Astrophysics Data System (ADS)

Due to insatiate demand for miniaturization of electronics, there is a need for new techniques to measure full-field strain at micro-scale structures. In addition, Micro-Electronic-Mechanical-Systems (MEMS) require a high resolution and high sensitivity material property characterization technique. In this study, a theoretic model for a high sensitivity Moire Interferometry (MI) for measuring nano-scale strain field has been developed. The study also includes the application of the proposed measurement technique for the study of reliability of next generation nano-electronics/power electronics. The study includes both theoretical and experimental work. In the theoretical part, a far field modeling of a Moire Interferometer (MI) using the mode decomposition method is proposed according to the analytical formulation from the scalar diffraction theory. The wave propagation within the defined MI far field domain is solved analytically for a single frequency surface relieved grating structure following the Rayleigh-Sommerfeld formulation under the paraxial approximation. It is shown that the far-field electrical field and the intensity interferogram can be calculated using the mode decomposition method. Furthermore, the near-field (propagation distance < 1 mum) assumptions are validated using exact electromagnetic (EM) theory; and the EM fields are simulated in a few microns region above the surface of the diffraction grating. The study shows that there is a strong correlation (correlation factor R = 0.869) of spatial frequency response between EM field and strain field at the nanoscale. Experimentally, a 164 nm/pixel spatial resolution Moire Interferometer with automated full strain field calculation is proposed. Accurate full strain field maps are generated automatically by a combination of phase shifting technique (temporal data redundancy) and Continuous Wavelet Transform (CWT) (spatial data redundancy). A thermal experiment on BGA packaging is used to demonstrate the advantages of the proposed new design. To enhance the stability of the phase shifting process, a statistical phase shifting estimation algorithm for temporal phase shifting interferometry (PSI) based on (CWT) is proposed. The proposed algorithm explores spatial information redundancy in the intra-frame interferogram data set using the phase recovery property on the power ridge of CWT. With the proposed MI, it is able to locate and measure the temperature of the hot spots caused by Joule Heating by measuring the free thermal expansion in-plane strain. It is demonstrated that the hotspot caused by the Joule heating in a thin metal film/plate structure can be measured by Phase shifting Moire interferometry with continuous wavelet transform (PSMI/CWT) at the microscopic scale. A demonstration on a copper film is conducted to verify the theory under different current densities. It is shown that a linear relationship exists between current density squared and normal strains.

Chen, Bicheng

242

High-intensity xenon plasma discharge lamp for bulk-sensitive high-resolution photoemission spectroscopy  

SciTech Connect

We have developed a highly brilliant xenon (Xe) discharge lamp operated by microwave-induced electron cyclotron resonance (ECR) for ultrahigh-resolution bulk-sensitive photoemission spectroscopy (PES). We observed at least eight strong radiation lines from neutral or singly ionized Xe atoms in the energy region of 8.4-10.7 eV. The photon flux of the strongest Xe I resonance line at 8.437 eV is comparable to that of the He I{alpha} line (21.218 eV) from the He-ECR discharge lamp. Stable operation for more than 300 h is achieved by efficient air-cooling of a ceramic tube in the resonance cavity. The high bulk sensitivity and high-energy resolution of PES using the Xe lines are demonstrated for some typical materials.

Souma, S.; Sato, T.; Takahashi, T.; Baltzer, P. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); MB Scientific AB, Seminariegatan 29B, Uppsala 752 28 (Sweden)

2007-12-15

243

Label-free biosensing with high sensitivity in dual-core microstructured polymer optical fibers  

E-print Network

as a highly sensitive, label-free, and selective biosensor. An immobilized antigen sensing layer on the walls sensitivity up to 20 nm/nm (defined as the shift in the resonance wavelength per nm biolayer) at visible

Vlachos, Kyriakos G.

244

The Subaru Coronagraphic Extreme AO High Speed and High Sensitivity Wavefront Sensors  

NASA Astrophysics Data System (ADS)

The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) system uses advanced coronagraphic technique for high contrast imaging of exoplanets and disks as close as 1 lambda/D from the host star. In addition to unusual optics, achieving high contrast at this small angular separation requires a wavefront sensing and control architecture which is optimized for exquisite control and calibration of low order aberrations. To complement the current near-IR wavefront control system driving a single MEMS type deformable mirror mounted on a tip-tilt mount, two high order and high sensitivity visible wavefront sensors have been integrated to SCEXAO: - a non modulated Pyramid wavefront sensor (CHEOPS) which is a sensitivity improvement over modulated Pyramid systems now used in high performant astronomical AO, - a non linear wavefront sensor designed in 2012 by Subaru Telescope with the collaboration of the NRC-CNRC which is expected to improve significantly the achieved sensitivity of low order aberations measurements. I will present the CHEOPS last results measured downstream the Subaru AO188 system highlighting limits of our instrument and then introduce the primary laboratory images of the first built prototype of the non linear curvature wavefront sensor.

Clergeon, Christophe; Guyon, Olivier; Martinache, Frantz; Veran, Jean-Pierre; Gendron, Eric; Rousset, Gérard; Correia, Carlos; Garrel, Vincent

2013-12-01

245

Determination of nine environmental phenols in urine by ultra-high-performance liquid chromatography-tandem mass spectrometry.  

PubMed

A method was developed to determine nine environmental phenols, including bisphenol A, 2,3,4-trichlorophenol, 2,4,5-trichlorophenol, pentachlorophenol, triclosan (2,4,4'-trichloro-2'-hydroxyphenylether), 4-tert-octylphenol, 4-n-octylphenol, 4-n-nolyphenol and benzophenone-3 (2-hydroxy-4-methoxybenzophenone) in human urine using ultra-high-performance liquid chromatography-tandem mass spectrometry (UPLC-MS-MS). The analytes were extracted and preconcentrated with solid-phase extraction, and then quantified with UPLC-electrospray ionization (negative ion mode)-MS-MS using multiple reaction monitoring mode. Limits of detection of the nine phenols ranged from 0.02 to 0.90 ng/mL. This method was further validated by the determination of phenols in 325 human urine samples that generated data regarding the exposure of various phenols to Chinese adults without occupational exposure to phenols. PMID:22989423

Chen, Minjian; Zhu, Pengfei; Xu, Bin; Zhao, Rencheng; Qiao, Shanlei; Chen, Xiaojiao; Tang, Rong; Wu, Di; Song, Ling; Wang, Shoulin; Xia, Yankai; Wang, Xinru

2012-01-01

246

[Clinical evaluation of routinely applied highly sensitive TSH-RIA].  

PubMed

Forty-one routine TSH assays were carried out by applying newly developed, highly sensitive TSH RIA (T. Mori, et al., Folia Endocrinol. Jap., 56: 1231, 1980). B/B0 percent of the least standard point (0.156 microU/ml) was consistently lower than B0 and higher than that of 0.31 microU/ml. The distributions of assayed TSH concentrations in 1394 sera revealed that 34.8% of the total were in an undetectable range when measured by conventional method (less than 1.0 microU/ml), but this method picked up 16.4% (0.156-1.0 microU/ml), and only 5.4% exceeded the upper limit (20 microU/ml). TRH test results (500 micrograms i.v. bolus) in 45 cases of thyroid disorders with low or normal basal TSH revealed that the peak TSH of those with basal TSH of 0.156-1.0 microU/ml (8.98 +/- 4.15 microU/ml) was significantly different from those of less than 0.156 microU/ml or 1.0-3.2 microU/ml. Further, TSH concentrations in 19 patients after T3 administration (75 micrograms X 7 days) were 0.183 +/- 0.073 microU/ml, and all but one (0.43 microU/ml) showed values lower than the normal range (0.31-3.2 microU/ml). Thyroid hormone concentrations in cases with TSH of 0.156-1.0 microU/ml were limited in the ranges of less than 300 ng/dl T3 and/or less than 15 micrograms/dl T4, and these were considered to be the threshold of definite TSH inhibition.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:6688785

Mori, T; Ishihara, T; Bito, S; Ikekubo, K

1983-07-20

247

Stochastic sensitivity measure for mistuned high-performance turbines  

NASA Technical Reports Server (NTRS)

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.

Murthy, Durbha V.; Pierre, Christophe

1992-01-01

248

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...

249

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...

250

Confirmation of phenolic acids and flavonoids in honeys by UPLC-MS  

Microsoft Academic Search

Certain phenolic acids and flavonoids are described in the literature as marker substances for several unifloral honeys. As\\u000a not all authors utilised the same methods for extraction and determination, there are remarkable discrepancies in the published\\u000a data concerning these substances. Ethyl acetate extracts which, aside from phenolic acids, also contain flavonoids were analysed\\u000a by Ultra Performance Liquid Chromatography-Quadrupole\\/Time of flight-mass

Sophie Trautvetter; Isabelle Koelling-Speer; Karl Speer

2009-01-01

251

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

PubMed Central

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

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

2014-01-01

252

UPLC-MS as a powerful technique for screening the nonvolatile contaminants in recycled PET.  

PubMed

The possibility of using recycled polyethylene terephthalate as a food contact material is being seriously considered, but the potential migration of nonvolatile compounds from it must be assessed to ensure that it is safe to do so. In the study presented here, four samples of recycled PET were each exposed to three food simulants under the harsh extraction conditions stipulated by European legislation regarding migration tests. The nonvolatile compounds that migrated from them were determined by ultra performance liquid chromatography-mass spectrometry using three different cone voltages, and both positive and negative ionization modes. A total of 36 chemical compounds were detected, some of which were identified, including common additives such as N,N'-di-beta-naphthyl-p-phenylenediamine (antioxidant) and 2,4-di-tert-butyl-6-(5-chloro-2H-benzotriazol-2-yl)phenol (light stabilizer) as well as degradation compounds such as ethylene terephthalate dimers and trimers. In addition, specific migration values of three common components of polyethylene terephthalate (diethylene glycol, terephthalic acid, and isophthalic acid) were determined and found to occur at levels of <1 mg/kg-much lower than the specific migration limits stipulated by European legislation. PMID:17546445

Bentayeb, K; Batlle, R; Romero, J; Nerín, C

2007-07-01

253

Simultaneous determination of cyromazine and dicyclanil in animal edible tissues using UPLC-MS/MS  

Technology Transfer Automated Retrieval System (TEKTRAN)

Cyromazine and dicyclanil are used as insect growth regulators. This article describes an easy and innovative simultaneous extraction for residues of cyromazine and dicyclanil in food of animal origin and the confirmation procedure using an ultra-performance liquid chromatography-electrospray ioniz...

254

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

PubMed

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

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

2014-09-23

255

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

NASA Astrophysics Data System (ADS)

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.

Mohammad, Mohammad Ali; Dew, Steven K.; Stepanova, Maria

2013-03-01

256

High Sensitivity High Performance Liquid Chromatography Electrospray Tandem Mass Spectrometry Determination of Terfenadine in Human Plasma  

Microsoft Academic Search

A highly sensitive and selective HPLC-MS-MS method was developed for the determination of terfenadine in human plasma. The analytes, terfenadine and terfenadine related compound A (internal standard), were extracted from human plasma by methyl t-butyl ether\\/methylene chloride\\/n-butyl chloride (3:2:1). The organic solvent is evaporated to dryness and reconstituted in 100 ?L of acetonitrile\\/0.02 M ammonium acetate buffer pH 3.5 (50:50).

Yau Yi Lau; Paul H. Anderson; Rasmy Talaat

1996-01-01

257

Design of a high sensitive non-faradaic impedimetric sensor.  

PubMed

An electrochemical approach towards identifying antigen-antibody binding interactions is studied by using a non-faradaic impedimetric sensor fabricated on a printed circuit board (PCB) chip. An electrical methodology for detecting protein interactions at ultra-low concentrations (in the femtogram/mL) regime has been demonstrated. Nanoporous alumina with pore diameter of 200nm and pore depth of 250 nm was used as the signal amplifying medium. Cardiac biomarker, brain natriuretic peptide (BNP) was used as the study marker in characterizing the sensor's sensitivity. A sensitivity of 10 femtogram/mL was determined based on the impedimetric signal response. Sensitivity was determined through Nyquist plot analysis for the non-faradaic interactions of the protein biomolecules. This paper is the first demonstration of clinically relevant limit of detection with the BNP biomarker. PMID:23366619

Panneer Selvam, Anjan; Vattipalli, Krishna M; Prasad, Shalini

2012-01-01

258

A high-sensitivity push-pull magnetometer  

SciTech Connect

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)

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

2014-01-13

259

A high-sensitivity push-pull magnetometer  

E-print Network

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

Breschi, E; Knowles, P; Weis, A

2013-01-01

260

Theoretical analysis of highly sensitive prism based surface plasmon resonance sensor with indium tin oxide  

NASA Astrophysics Data System (ADS)

An extremely sensitive silica glass prism based SPR sensor with indium tin oxide (ITO) layer is presented and theoretically analyzed. The sensitivity of the sensor enhances with the increase in the thickness of ITO layer. With optimized values of thickness of ITO layer and incident wavelength to be 50 nm and 1600 nm, respectively, the proposed sensor offers high sensitivity of 164°/RIU.

Sharma, Navneet K.; Yadav, Swati; Sajal, Vivek

2014-05-01

261

High sensitivity wavefront sensing with the non-linear curvature WFS  

E-print Network

1 High sensitivity wavefront sensing with the non-linear curvature WFS Olivier Guyon University to use the WFS in open loop - possible to "dial in" large offset aberrations Sensitivity: The WFS should requirements. #12;Wavefront Sensor Options... Linearity, dynamical range and sensitivity Linear, large

Guyon, Olivier

262

High sensitivity cantilevers for measuring persistent currents in normal metal rings  

E-print Network

High sensitivity cantilevers for measuring persistent currents in normal metal rings A. C to measuring persistent currents in normal metal rings. By integrating micron-scale metal rings into sensitive the rings' persistent currents with greater sensitivity than the superconducting quantum interference device

Harris, Jack

263

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

PubMed

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

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

2014-01-01

264

ORIGINAL PAPER Allergen microarrays on high-sensitivity silicon slides  

E-print Network

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

265

Coomassie blue staining for high sensitivity gel-based proteomics.  

PubMed

Gel electrophoresis, particularly one- (1DE) and two-dimensional electrophoresis (2DE), remain among the most widely used top-down methods for resolving and analysing proteomes. Detection of the resulting protein maps relies on staining (i.e. colloidal coomassie blue (CCB) or SYPRO Ruby (SR), in addition to many others). Fluorescent in-gel protein stains are generally preferred for higher sensitivity, reduced background, and wider dynamic range. Although traditionally used for densitometry, CBB has fluorescent properties. Indeed, infrared detection of CCB stained protein was comparable to SR, with BioSafe (Bio-Rad) and the Neuhoff formulation (NCCB) identified as potentially superior to SR; a minor sensitivity issue encountered in gel-resolved proteomes; might have been due to the unified staining protocol used. Here the staining protocol for both CCB formulations was optimised, yielding improved selectivity without affecting sensitivity; the resulting linear dynamic range was similar for BioSafe and NCCB and somewhat better than SR. 2D gel-based analyses of mouse brain and Arabidopsis thaliana (leaf) proteomes indicated markedly superior spot detection using the NCCB formulation. Thus more sensitive, quantitative in-gel protein analyses can be achieved using NCCB, at a fraction of the cost. PMID:23428344

Gauci, Victoria J; Padula, Matthew P; Coorssen, Jens R

2013-09-01

266

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

SciTech Connect

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.

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

2006-01-01

267

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

SciTech Connect

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.

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

268

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

NASA Astrophysics Data System (ADS)

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 104, 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.

Clevenson, Hannah; Desjardins, Pierre; Gan, Xuetao; Englund, Dirk

2014-06-01

269

A Surface Micromachined Piezoresistive Pressure Sensor with High Sensitivity  

Microsoft Academic Search

This paper presents a surface micromachined piezoresistive absolute pressure sensor with improved performance. A sensitivity of about 11 mV\\/V\\/bar in the range 0-500 mbar overpressure has been achieved. The sensor contains four polysilicon piezoresistors arranged in a Wheatstone bridge at the underside of a polysilicon membrane to reduce invironmental influences (e.g. light, moisture). Position and size of the piezoresistors has

T. Lisec; M. Kreutzer; B. Wagner

1995-01-01

270

Temperature-independent FBG pressure sensor with high sensitivity  

Microsoft Academic Search

This study develops a fiber Bragg grating (FBG) pressure sensor partly shielded with a metal tube. The thermal-strain cross effect is avoided and its pressure sensitivity is increased to ?2.44×10?3 MPa, about 1200 times as that of a bare fiber grating. Due to its good sensing linearity, this sensor can be applied in the measurement of hydraulic pressure and vibration.

Lihui Liu; Hao Zhang; Qida Zhao; Yuliang Liu; Fang Li

2007-01-01

271

Low frequency, high sensitive tunable mechanical monolithic horizontal sensors  

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

272

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

PubMed

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

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

2014-10-01

273

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

E-print Network

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

Paris-Sud XI, Université de

274

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

E-print Network

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

Otani, Yoshichika

275

Coordinate-sensitive ionization chamber with high spatial resolution  

NASA Astrophysics Data System (ADS)

The coordinate sensitive ionization chamber for measurement of parameters of a synchrotron radiation beam in the X-ray range was designed. The parameters of the chamber are as follows: (1) coordinate resolution better than 1 ?m; (2) range of measurements in the cross-section of SR beam is 10 mm; (3) dynamic ranges ˜10 5; (4) the apertures of the entrance window are 12×24 mm; (5) the material of the window is Be; (6) Ar gas; (7) frequency of measurements is 6-50 Hz; (8) interface is Ethernet.

Fisenko, A. N.; Kosov, A. V.; Kozak, V. R.; Kuper, E. A.; Pirogov, B. Ja.; Sheromov, M. A.; Zolotarev, K. V.

2005-05-01

276

High order sensitivity analysis of complex, coupled systems  

NASA Technical Reports Server (NTRS)

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.

Sobieszczanski-Sobieski, Jaroslaw

1990-01-01

277

High refractive index sensitivity sensing in gold nanoslit arrays  

NASA Astrophysics Data System (ADS)

The extraordinary optical transmission (EOT) phenomenon of nano-periodic aperture array in metallic film has been widely investigated and used in biosensors. The surface plasmon resonance and cavity mode in some periodic nanostructures, such as nanohole and nanoslit, cause EOTs at certain wavelengths. This resonance wavelength is sensitive to the refractive index on the surface of periodic nanostructures. Therefore, the metallic nanostructures are expected to be good sensing elements. The sensing performances of gold nanoslit arrays are experimentally and theoretically investigated. Three-dimensional finite difference time domain (FDTD) simulations are utilized to explore their transmission spectra and steady-state field intensity distributions. The electron beam evaporation, electron beam lithography, and ion milling are applied to the gold nanoslit arrays with different widths and periods. The sensing performances of the gold nanoslit array are characterized via transmission spectra in four kinds of refractive index samples. The highest sensitivity reaches 726 nm/RIU when the width of the gold nanoslit array is 38.5 nm.

Yuan, Jun; Kan, Qiang; Geng, Zhao-Xin; Xie, Yi-Yang; Wang, Chun-Xia; Chen, Hong-Da

2014-08-01

278

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

SciTech Connect

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.

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

279

Quantitative, high sensitivity, high resolution, nuclear microprobe imaging of fluids, melts and minerals  

NASA Astrophysics Data System (ADS)

Samples of fluids and melts trapped and preserved as inclusions in growing minerals or healed fractures provide unique windows on a range of geological processes from mantle melting and metasomatism through to economic ore formation and remobilization. Recent advances in nuclear microprobe (NMP) technology at the CSIRO provide powerful tools for the study of these inclusions and associated mineral assemblages. These tools include a new NMP designed for high resolution and high sensitivity, PIXE analytical methods for quantitative imaging and analysis, and simultaneous PIGE imaging. The quantitative imaging and analysis methods are based on the dynamic analysis approach, which generates a fast matrix transform for projection of list-mode PIXE data onto pure elemental images. Recent advances provide rapid pixel-by-pixel correction for matrix and absorption effects in different (mineral) compositions across the image area to yield true quantitative images. These methods are combined in a software package called GeoPIXE II.

Ryan, C. G.; van Achterbergh, E.; Yeats, C. J.; Drieberg, S. L.; Mark, G.; McInnes, B. M.; Win, T. T.; Cripps, G.; Suter, G. F.

2002-04-01

280

A new compact, high sensitivity neutron imaging system  

SciTech Connect

We have developed a new small neutron imaging system (SNIS) diagnostic for the OMEGA laser facility. The SNIS uses a penumbral coded aperture and has been designed to record images from low yield (10{sup 9}-10{sup 10} neutrons) implosions such as those using deuterium as the fuel. This camera was tested at OMEGA in 2009 on a rugby hohlraum energetics experiment where it recorded an image at a yield of 1.4 Multiplication-Sign 10{sup 10}. The resolution of this image was 54 {mu}m and the camera was located only 4 meters from target chamber centre. We recently improved the instrument by adding a cooled CCD camera. The sensitivity of the new camera has been fully characterized using a linear accelerator and a {sup 60}Co {gamma}-ray source. The calibration showed that the signal-to-noise ratio could be improved by using raw binning detection.

Caillaud, T.; Landoas, O.; Briat, M.; Rosse, B.; Thfoin, I.; Philippe, F.; Casner, A.; Bourgade, J. L.; Disdier, L. [CEA, DAM, DIF,F-91297 Arpajon (France); Glebov, V. Yu.; Marshall, F. J.; Sangster, T. C. [Laboratory for Laser Energetics, University of Rochester, 250 East River Road, Rochester, New York 14623-1299 (United States); Park, H. S.; Robey, H. F.; Amendt, P. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)

2012-10-15

281

Particles and microfluidics merged: perspectives of highly sensitive diagnostic detection  

PubMed Central

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

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

2014-01-01

282

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

SciTech Connect

Three quasi-one-dimensional magnetoelectric (ME) magnetic field sensors, each with a different magnetostrictive wire material, were investigated in terms of sensitivity and noise floor. Magnetostrictive Galfenol, iron-cobalt-vanadium, and iron-nickel wires were examined. Sensitivity profiles, hysteresis effects, and noise floor measurements for both optimally biased and zero-biased conditions are presented. The FeNi wire (FN) exhibits high sensitivity (5.36?mV/Oe) at bias fields below 22?Oe and an optimal bias of 10?Oe, whereas FeGa wire (FG) exhibits higher sensitivity (6.89 mW/Oe) at bias fields >22?Oe. The sensor of FeCoV wire (FC) presents relatively low sensitivity (2.12?mV/Oe), due to low magnetostrictive coefficient. Each ME tube-topology sensor demonstrates relatively high sensitivity at zero bias field, which results from a magnetic shape anisotropy and internal strain of the thin magnetostrictive wire.

Gillette, Scott M.; Fitchorov, Trifon; Obi, Ogheneyunume; 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

283

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

PubMed Central

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

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

2014-01-01

284

High-sensitivity optical recording in KTN by two-photon absorption  

Microsoft Academic Search

Birefringence changes are induced in a cubic potassium tantalate niobate crystal with an external electric field by two-photon absorption of picosecond optical pulses. The recording sensitivity of 100 muJ\\/cm2 for elementary holograms with a few percent reconstruction efficiency is comparable to the sensitivity of holographic silver halide emulsions. The high sensitivity of KTN is shown to be due to efficient

D. von der Linde; A. M. Glass; K. F. Rodgers

1975-01-01

285

High?sensitivity optical recording in KTN by two?photon absorption  

Microsoft Academic Search

Birefringence changes are induced in a cubic potassium tantalate niobate crystal with an external electric field by two?photon absorption of picosecond optical pulses. The recording sensitivity of 100 ?J\\/cm2 for elementary holograms with a few percent reconstruction efficiency is comparable to the sensitivity of holographic silver halide emulsions. The high sensitivity of KTN is shown to be due to efficient

D. von der Linde; A. M. Glass; K. F. Rodgers

1975-01-01

286

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

Microsoft Academic Search

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

Randi E. Mccabe

1999-01-01

287

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

E-print Network

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

Howat, Ian M.

288

Signal-enhancing thermosensitive liposomes for highly sensitive immunosensor development.  

PubMed

Liposomes are potential candidates as nanovesicles for the development of detection systems with improved sensitivity and detection limits, due to their capacity to encapsulate diverse types of signal enhancing molecules. An amperometric immunosensor exploiting enzyme encapsulating thermosensitive liposomes for the ultrasensitive detection of carcinoembryonic antigen (CEA) is reported. Five different bioconjugation methods to link an anti-CEA antibody to horseradish peroxidase (HRP) encapsulating liposomes were studied and compared to HRP-Ab conjugate. ?-Potential measurements of liposomes before and after each modification method as well as following incubation with CEA were used as a tool to monitor the success of modification and probe the affinity of the liposome linked antibodies. The use of different lysing conditions (temperature vs detergent) was evaluated, with the application of temperature providing an extremely effective means of liposome lysis. Finally, thermosensitive liposomes modified using biotin-streptavidin and N-succinimidyl-S-acetylthioacetate (SATA)/sulfosuccinimidyl 4-(N-maleimidomethyl) cyclohexane-1-1-carboxylate (Sulfo-SMCC) chemistries were used to detect CEA and compared in terms of their stability, background signal, and limit of detection. Detection limits of 2 orders of magnitude lower than that obtained with the HRP-antibody reporter conjugate were obtained (0.080 ng CEA/mL and 0.0113 ng CEA/mL), with 11-fold and 9-fold amplification of signal, for the biotin-streptavidin and SATA/Sulfo-SMCC modified liposomes respectively, clearly demonstrating the powerful potential of enzyme encapsulating liposomes as signal enhancement tools. PMID:21155541

Genç, Rükan; Murphy, Deirdre; Fragoso, Alex; Ortiz, Mayreli; O'Sullivan, Ciara K

2011-01-15

289

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

PubMed Central

Giardiasis, a gastrointestinal disease caused by Giardia duodenalis, is currently treated mainly with nitroimidazoles, primarily metronidazole (MTZ). Treatment failure rates of up to 20 percent reflect the compelling need for alternative treatment options. Here, we investigated whether orlistat, a drug approved to treat obesity, represents a potential therapeutic agent against giardiasis. We compared the growth inhibitory effects of orlistat and MTZ on a long-term in vitro culture adapted G. duodenalis strain, WB-C6, and on a new isolate, 14-03/F7, from a patient refractory to MTZ treatment using a resazurin assay. The giardiacidal concentration of the drugs and their combined in vitro efficacy was determined by median-effect analysis. Morphological changes after treatment were analysed by light and electron microscopy. Orlistat inhibited the in vitro growth of G. duodenalis at low micromolar concentrations, with isolate 14-03/F7 (IC5024h?=?2.8 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

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

2013-01-01

290

High Explosive Deonation Threshold Sensitivity Due to Multiple Fragment Impacts  

Microsoft Academic Search

Fragments, bullets or projectiles can initiate a detonation in a high explosive (HE). For this to happen certain critical conditions need to be exceeded. For a given explosive, these critical conditions are the projectile velocity, the projectile size and shape, and the projectile material properties. A lot of work has been done in the area of metal shaped charge jets

V Georgevich; P Pincosy; J Chase

2004-01-01

291

UNCERTAINTY AND SENSITIVITY ANALYSES FOR VERY HIGH ORDER MODELS  

EPA Science Inventory

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

292

HIGH SENSITIVITY MASS SPECTROMETRY OF THE RARE GASES  

Microsoft Academic Search

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

1959-01-01

293

High-sensitivity mass spectrometry with a tandem accelerator  

SciTech Connect

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.

Henning, W.

1983-01-01

294

Development of a High-Sensitivity Radiation Detector for Chromatography  

Microsoft Academic Search

We describe a radiotracer imaging system for mea- suring the biochemical production rates of organic compounds from animals or plants. It uses a high performance liquid chro- matography (HPLC) column to separate the compounds and a parallel-plane radiation detector to measure the disintegrations from each compound over a period of time. Because the mea- surement time is much longer than

Jennifer S. Huber; Stephen M. Hanrahan; William W. Moses; Steve E. Derenzo; Bryan W. Reutter; James P. O'Neil; Grant T. Gullberg

2011-01-01

295

Enhanced Laboratory Sensitivity to Variation of the Fine-Structure Constant using Highly Charged Ions  

NASA Astrophysics Data System (ADS)

We study atomic systems that are in the frequency range of optical atomic clocks and have enhanced sensitivity to potential time variation of the fine-structure constant ?. The high sensitivity is due to coherent contributions from three factors: high nuclear charge Z, high ionization degree, and significant differences in the configuration composition of the states involved. Configuration crossing keeps the frequencies in the optical range despite the large ionization energies. We discuss a few promising examples that have the largest ? sensitivities seen in atomic systems.

Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.

2010-09-01

296

Design and simulation of high sensitive capacitive pressure sensor with slotted diaphragm  

Microsoft Academic Search

This paper presents a high sensitive MEMS capacitive pressure sensor for biomedical applications. Two sensor designs incorporating clamped and slotted diaphragm are implemented and compared to realize the pressure-sensitive components. The pressure sensor has been designed to measure pressures in the range of 0 to 60 mmhg that is in the range of intraocular pressure sensors. Intraocular pressure sensors are

M. Shahiri-Tabarestani; B. A. Ganji; R. Sabbaghi-Nadooshan

2012-01-01

297

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

E-print Network

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

Schmittner, Andreas

298

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

PubMed

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

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

2013-03-21

299

Label-Free Biomedical Imaging with High Sensitivity by Stimulated Raman Scattering Microscopy  

Microsoft Academic Search

Label-free chemical contrast is highly desirable in biomedical imaging. Spontaneous Raman microscopy provides specific vibrational signatures of chemical bonds, but is often hindered by low sensitivity. Here we report a three-dimensional multiphoton vibrational imaging technique based on stimulated Raman scattering (SRS). The sensitivity of SRS imaging is significantly greater than that of spontaneous Raman microscopy, which is achieved by implementing

Christian W. Freudiger; Wei Min; Brian G. Saar; Sijia Lu; Gary R. Holtom; Chengwei He; Jason C. Tsai; Jing X. Kang; X. Sunney Xie

2008-01-01

300

Highly Sensitive and Easy-to-Use SQUID Sensors  

Microsoft Academic Search

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

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

2007-01-01

301

Purification of ethanol for highly sensitive self-assembly experiments  

PubMed Central

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

Barbe, Kathrin; Kind, Martin; Pfeiffer, Christian

2014-01-01

302

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

PubMed

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

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

303

Application of the Mirrorball High-Sensitivity Cytometer to Multiplexed Assays for Antibody Drug Discovery.  

PubMed

Highly sensitive, high-throughput assay technologies are required for the identification of antibody therapeutics. Multiplexed assay systems are particularly advantageous because they allow evaluation of several parameters within 1 well, increasing throughput and reducing hands-on laboratory time. The mirrorball (TTP Labtech), using high-throughput fluorometric microvolume assay technology, offers simultaneous scanning with up to 3 lasers as well as laser scatter detection. This makes the mirrorball especially suitable for the development of highly sensitive and multiplexed assays. We have developed bead- and cell-based binding assays that demonstrate how the multilaser capability of the mirrorball can be exploited to enhance assay sensitivity. In addition, using the multilaser simultaneous scanning capability, we have established multiplexed cytokine quantitation assays and antibody-cell binding assays. Our results demonstrate the potential utility of this technology to improve the sensitivity and efficiency of biologics screening, resulting in streamlining of the lead antibody selection process. PMID:25381256

England, Elizabeth; Newton, Philip; Neal, Frances; Kitching, Lisa; Colley, Caroline; Rossant, Christine J

2014-11-01

304

Postsynthetic lanthanide functionalization of nanosized metal-organic frameworks for highly sensitive ratiometric luminescent thermometry.  

PubMed

A straightforward postsynthetic lanthanide functionalization strategy is developed for fabricating highly sensitive ratiometric luminescent nanothermometers based on nanosized MOFs, which highlights the ability of a broad range of nanosized MOFs to construct nanothermometers. PMID:25345472

Zhou, You; Yan, Bing; Lei, Fang

2014-12-14

305

Prevalence and significance of detectable troponins as measured by highly sensitive assays in the general population.  

PubMed

Cardiac troponins, when measured using highly sensitive assays, appear to be among the most powerful prognostic biomarkers yet identified for risk assessment in the general population. Very low troponin levels detectable with these highly sensitive assays are correlated with multiple clinical determinants of future heart failure risk and cardiovascular death. Corresponding imaging evidence of subclinical heart disease includes strong associations between cardiac troponins, left ventricular hypertrophy, and reduced left ventricular ejection fraction. This is in contrast to the poor correlation with coronary disease. Cardiac troponins provide complementary information to natriuretic peptides, as well as measures of renal function, and appear to outperform high-sensitivity C-reactive protein in predicting risk for a variety of cardiovascular disease endpoints. Additional research is now needed to define the role of highly sensitive troponin assays in screening of the general population and risk assessment. PMID:24201087

de Lemos, James A; deFilippi, Christopher R

2013-12-01

306

“Ultra-high resolution optical trap with single fluorophore sensitivity”  

PubMed Central

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

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

2013-01-01

307

Stretchable and highly sensitive graphene-on-polymer strain sensors  

PubMed Central

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

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

308

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

NASA Technical Reports Server (NTRS)

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.

Schwinghamer, R. J.

1972-01-01

309

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

NASA Astrophysics Data System (ADS)

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.

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

2012-09-01

310

Highly Sensitive Signal Detection in Stimulated Parametric Emission Microscopy Based on Two-Beam Interferometry  

NASA Astrophysics Data System (ADS)

We present a simple and highly sensitive optical detection method based on two-beam interferometry for application to coherent nonlinear optical microscopy (CNOM). The theoretical sensitivity of this method is higher than that of conventional spectral interferometry (SI). We experimentally applied this technique to stimulated parametric emission (SPE) microscopy and achieved a high sensitivity that is only 4 or 5 dB lower than that of a theoretical shot noise limit. In order to validate the practical applicability of this technique, we demonstrated a noise reduction experiment in the observation of a plant cell with an SPE microscope.

Yamagiwa, Masatomo; Ozeki, Yasuyuki; Kawasumi, Takehito; Kajiyama, Shin'ichiro; Fukui, Kiichi; Itoh, Kazuyoshi

2008-12-01

311

High sensitivity microchannel plate detectors for space extreme ultraviolet missions.  

PubMed

Microchannel plate (MCP) detectors have been widely used as two-dimensional photon counting devices on numerous space EUV (extreme ultraviolet) missions. Although there are other choices for EUV photon detectors, the characteristic features of MCP detectors such as their light weight, low dark current, and high spatial resolution make them more desirable for space applications than any other detector. In addition, it is known that the photocathode can be tailored to increase the quantum detection efficiency (QDE) especially for longer UV wavelengths (100-150 nm). There are many types of photocathode materials available, typically alkali halides. In this study, we report on the EUV (50-150 nm) QDE evaluations for MCPs that were coated with Au, MgF(2), CsI, and KBr. We confirmed that CsI and KBr show 2-100 times higher QDEs than the bare photocathode MCPs, while Au and MgF(2) show reduced QDEs. In addition, the optimal geometrical parameters for the CsI deposition were also studied experimentally. The best CsI thickness was found to be 150 nm, and it should be deposited on the inner wall of the channels only where the EUV photons initially impinge. We will also discuss the techniques and procedures for reducing the degradation of the photocathode while it is being prepared on the ground before being deployed in space, as adopted by JAXA's EXCEED mission which will be launched in 2013. PMID:22938284

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

2012-08-01

312

(abstract) A Miniature, High-Sensitivity, Electron-Tunneling Accelerometer  

NASA Technical Reports Server (NTRS)

A prototype low-noise accelerometer has been fabricated with an electron-tunneling transducer. By measuring the tunneling current between an electrode on the proof mass and a feedback-controlled monitor electrode, very small accelerations can be detected with high responsivity. This particular prototype (10x10x1.5 mm) was designed for underwater acoustic measurement from a few hertz to 1 kHz. The measured responsivity below the fundamental device resonance at 100 Hz is roughly 1500 volts per m/s(sup 2) with a measured noise spectral density of 10(sup -6) m/s(sup 2) per root hertz or less between 30 and 300 Hz. The noise floor is controlled primarily by 1/f noise in the tunneling current although the noise floor reaches the theoretical molecular-agitation limit at 100 hertz. The responsivity and directivity of the device were measured in a standard gradient-hydrophone calibrator; the noise floor was determined in a vacuum-ionization chamber assembled from commercial off-the-shelf components; and the detailed dynamics of the proof-mass motion were examined using a heterodyne laser interferometer that was scanned across the surface and synchronously detected with respect to the excitation.

Gabrielson, Thomas B.; Rockstad, Howard K.; Tang, Tony K.

1994-01-01

313

Radiation sensitivity enhancement in cells using high-Z nanoparticles  

NASA Astrophysics Data System (ADS)

Cerium-doped lanthanum fluoride colloidal nanocrystals offer a way to improve radiation therapy through the enhanced absorption of high-energy photons. Lanthanum fluoride nanocrystals doped with 10% cerium and capped with oleic acid were synthesized in anhydrous methanol as platelets 3-6 nm in diameter and 1-3 nm thick. The nanocrystals were characterized by transmission electron microscopy and photoluminescence spectroscopy. Previously synthesized lanthanum fluoride nanocrystals doped with 10% cerium and capped with hydroxyl were used in radiation dose enhancement experiments that involved an incoming gamma flux from a 137Cs source and a FOX assay to measure absorbed energy. Possibility for lanthanide ions to be released into solution under gamma irradiation and to interfere with the assay was shown after the results were compared with the outcome of a similar previous experiment with the Fricke dosimeter solution. Finally, increased cell mortality of S. cerevisiae under gamma irradiation was observed in the presence of hydroxyl-capped lanthanum fluoride nanocrystals in the solution.

Withers, Nathan J.; Plumley, John B.; Akins, Brian A.; Rivera, Antonio C.; Medina, Gloria; Smolyakov, Gennady A.; Timmons, Graham S.; Osinski, Marek

2010-02-01

314

Highly sensitive biochemical sensor utilizing Bragg grating in submicron Si/SiO2 waveguides  

NASA Astrophysics Data System (ADS)

We present a novel highly sensitive biochemical sensor based on a Bragg grating written in the cladding region of a submicron planar Si/SiO2 waveguide. Owing to the high refractive index contrast at the Si/SiO2 boundary the TM modal power is relatively high in low refractive index sensing region, leading to higher sensitivity in this configuration [1]. Waveguide parameters have been optimized to obtain maximum modal power in the sensing region (PSe) and an optimum core width corresponding to maximum sensitivity is found to exist while operating in TM mode configuration, as has been shown in Fig. 1. It has been found that operating in TM mode configuration at optimum core width the structure exhibits extremely high sensitivity, ~ 5×10-6 RIU - 1.35×10-6 RIU for the ambient refractive indices between 1.33 - 1.63. Such high sensitivities are typically attainable for Surface Plasmon Polariton (SPP) based biosensors and is much higher than any non SPP based sensors. Being free from any metallic layer or bulky prism the structure is easy to realize. Owing to its simple structure and small dimensions the proposed sensor can be integrated with planar lightwave circuits and could be used in handy lab-on-a-chip devices. The device may find application in highly sensitive biological/chemical sensing areas in civil and defense sectors where analyzing the samples at the point of need is required rather than sending it to some centralized laboratory.

Tripathi, Saurabh Mani; Kumar, Arun; Meunier, Jean-Pierre; Marin, Emmanuel

2009-05-01

315

Confidence Level and Sensitivity Limits in High Contrast Imaging  

SciTech Connect

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

Marois, C

2007-11-07

316

Confidence Level and Sensitivity Limits in High Contrast Imaging  

SciTech Connect

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

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

2008-06-02

317

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

NASA Technical Reports Server (NTRS)

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.

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

2001-01-01

318

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

PubMed Central

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

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

2014-01-01

319

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

PubMed

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

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

2014-02-01

320

Variable sensitivity of US maize yield to high temperatures across developmental stages  

NASA Astrophysics Data System (ADS)

The sensitivity of maize to high temperatures has been widely demonstrated. Furthermore, field work has indicated that reproductive development stages are particularly sensitive to stress, but this relationship has not been quantified across a wide geographic region. Here, the relationship between maize yield and temperature variations is examined as a function of developmental stage. US state-level data from the National Agriculture Statistics Service provide dates for six growing stages: planting, silking, doughing, dented, mature, and harvested. Temperatures that correspond to each developmental stage are then inferred from a network of weather station observations interpolated to the county level, and a multiple linear regression technique is employed to estimate the sensitivity of county yield outcomes to variations in growing-degree days and an analogous measure of high temperatures referred to as killing-degree days. Uncertainties in the transition times between county-level growth stages are accounted for. Results indicate that the silking and dented stages are generally the most sensitive to killing degree days, with silking the most sensitive stage in the US South and dented the most sensitive in the US North. These variable patterns of sensitivity aid in interpreting which weather events are of greatest significance to maize yields and provide some insight into how shifts in planting time or changes in developmental timing would influence the risks associated with exposure to high temperatures.

Butler, E. E.; Huybers, P. J.

2013-12-01

321

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

322

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

E-print Network

among photonic crystal biosensors. We experimentally demon- strated mass sensitivity 8.8 atto focused on demon- strating on-chip microarrays for diagnostic assays in diverse fields of science sensitivity than other devices. Since the first demon- stration of biosensors on the photonic crystal platform

Texas at Austin, University of

323

Fully printed, highly sensitive multifunctional artificial electronic whisker arrays integrated with strain and temperature sensors.  

PubMed

Mammalian-mimicking functional electrical devices have tremendous potential in robotics, wearable and health monitoring systems, and human interfaces. The keys to achieve these devices are (1) highly sensitive sensors, (2) economically fabricated macroscale devices on flexible substrates, and (3) multifunctions beyond mammalian functions. Although highly sensitive artificial electronic devices have been reported, none have been fabricated using cost-effective macroscale printing methods and demonstrate multifunctionalities of artificial electronics. Herein we report fully printed high-sensitivity multifunctional artificial electronic whiskers (e-whisker) integrated with strain and temperature sensors using printable nanocomposite inks. Importantly, changing the composition ratio tunes the sensitivity of strain. Additionally, the printed temperature sensor array can be incorporated with the strain sensor array beyond mammalian whisker functionalities. The sensitivity for the strain sensor is impressively high (?59%/Pa), which is the best sensitivity reported to date (>7× improvement). As the proof-of-concept for a truly printable multifunctional artificial e-whisker array, two- and three-dimensional space and temperature distribution mapping are demonstrated. This fully printable flexible sensor array should be applicable to a wide range of low-cost macroscale electrical applications. PMID:24580035

Harada, Shingo; Honda, Wataru; Arie, Takayuki; Akita, Seiji; Takei, Kuniharu

2014-04-22

324

Luminescence sensitivity changes in natural quartz induced by high temperature annealing: a high frequency EPR and OSL study  

Microsoft Academic Search

Quartz undergoes very significant luminescence sensitivity changes after high temperature annealing (0-1200 °C), with particular enhancement occurring between the phase transition temperatures 573 and 870 °C. In order to understand why this occurs, high frequency electron paramagnetic resonance (EPR), operating at 90 GHz, has been used to monitor the structure and population of defects in natural sedimentary quartz, following annealing

N. R. J. Poolton; G. M. Smith; P. C. Riedi; E. Bulur; L. Bøtter-Jensen; A. S. Murray; M. Adrian

2000-01-01

325

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

NASA Astrophysics Data System (ADS)

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

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

2008-09-01

326

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

NASA Astrophysics Data System (ADS)

We propose a side-core holey fiber (SCHF)-based surface plasmon resonance (SPR) sensor to achieve high refractive index (RI) sensitivity. The SCHF structure can facilitate analyte filling and enhance the overlapping area of the core mode and surface plasmon polariton (SPP) mode. The coupling properties of the sensor are analyzed by numerical simulation. The maximum sensitivity of 5000 nm/RIU in an RI range of 1.33–1.44, and the average sensitivity of 9295 nm/RIU in an RI range from 1.44 to 1.54 can be obtained.

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

2014-10-01

327

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

E-print Network

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

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

2013-01-01

328

Adjoint techniques for sensitivity analysis in high-frequency structure CAD  

Microsoft Academic Search

There is a revival of the interest in adjoint sensitivity analysis techniques. This is partly because current computer-aided-design software based on full-wave electromagnetic (EM) solvers remains too slow for the purposes of practical high-frequency structure design despite the increasing capacity of computers. The adjoint-variable methods for design sensitivity analysis offer computational speed and accuracy. They can be used for efficient

N. K. Nikolova; J. W. Bandler; M. H. Bakr

2004-01-01

329

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

Microsoft Academic Search

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

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

2006-01-01

330

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

Microsoft Academic Search

Dye-sensitized solar cells based on nanoporous oxide semiconductor thin films such as TiO2, Nb2O5, ZnO, SnO2, and In2O3 with mercurochrome as the sensitizer were investigated. Photovoltaic performance of the solar cell depended remarkably on the semiconductor materials. Mercurochrome can convert visible light in the range of 400–600nm to electrons. A high incident photon-to-current efficiency (IPCE), 69%, was obtained at 510nm

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

2000-01-01

331

High-sensitivity temperature-independent differential pressure sensor using fiber Bragg gratings.  

PubMed

By means of novel packaged-structure design, a temperature independent differential pressure sensor based on fiber Bragg gratings with high sensitivity is experimentally demonstrated. The differential pressure sensitivity of the sensor can reach to 821.87nm/MPa. This device can also be used for simultaneous measurement of temperature and differential pressure, which is suitable for applications involving measurement of liquid level, liquid density or specific gravity detection. PMID:18825240

Sheng, Hao-Jan; Liu, Wen-Fung; Lin, Kuei-Ru; Bor, Sheau-Shong; Fu, Ming-Yue

2008-09-29

332

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

SciTech Connect

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.

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

333

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

Microsoft Academic Search

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

Scott A. Braun; Wei-Kuo Tao

2000-01-01

334

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

E-print Network

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

Buckingham, Michael

335

Simple Fabrication of a Highly Sensitive Glucose Biosensor Using Enzymes Immobilized in Exfoliated Graphite Nanoplatelets Nafion  

E-print Network

Simple Fabrication of a Highly Sensitive Glucose Biosensor Using Enzymes Immobilized in Exfoliated for the development of a glucose biosensor. Exfoliated graphite nanoplatelets (xGnP) were tested to enhance­isopropyl-alcohol solution with a high concentrated organic solvent (85 wt%). The resulting biosensors showed rapid response

Lee, Ilsoon

336

Real-Time High-Sensitivity Impedance Measurement Interface for Tethered BLM Biosensor Arrays  

E-print Network

Real-Time High-Sensitivity Impedance Measurement Interface for Tethered BLM Biosensor Arrays Yuksel lipid membrane (tBLM) biosensors. The circuit comprises a small number of high performance components and the current response to membrane resistance (RM) change of the tBLM biosensor is converted to voltage

De Micheli, Giovanni

337

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

PubMed Central

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

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

2014-01-01

338

Thyroglobulin measurement using highly sensitive assays in patients with differentiated thyroid cancer: a clinical position paper.  

PubMed

Differentiated thyroid cancer (DTC) is the most common endocrine cancer and its incidence has increased in recent decades. Initial treatment usually consists of total thyroidectomy followed by ablation of thyroid remnants by iodine-131. As thyroid cells are assumed to be the only source of thyroglobulin (Tg) in the human body, circulating Tg serves as a biochemical marker of persistent or recurrent disease in DTC follow-up. Currently, standard follow-up for DTC comprises Tg measurement and neck ultrasound combined, when indicated, with an additional radioiodine scan. Measurement of Tg after stimulation by endogenous or exogenous TSH is recommended by current clinical guidelines to detect occult disease with a maximum sensitivity due to the suboptimal sensitivity of older Tg assays. However, the development of new highly sensitive Tg assays with improved analytical sensitivity and precision at low concentrations now allows detection of very low Tg concentrations reflecting minimal amounts of thyroid tissue without the need for TSH stimulation. Use of these highly sensitive Tg assays has not yet been incorporated into clinical guidelines but they will, we believe, be used by physicians caring for patients with DTC. The aim of this clinical position paper is, therefore, to offer advice on the various aspects and implications of using these highly sensitive Tg assays in the clinical care of patients with DTC. PMID:24743400

Giovanella, Luca; Clark, Penelope M; Chiovato, Luca; Duntas, Leonidas; Elisei, Rossella; Feldt-Rasmussen, Ulla; Leenhardt, Laurence; Luster, Markus; Schalin-Jäntti, Camilla; Schott, Matthias; Seregni, Ettore; Rimmele, Herald; Smit, Jan; Verburg, Frederik A

2014-08-01

339

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

PubMed

Nanowires of various materials and configurations have been shown to be highly effective in the detection of chemical and biological species. In this paper, we report a novel, nanosphere-enabled approach to fabricating highly sensitive gas sensors based on ordered arrays of vertically aligned silicon nanowires topped with a periodically porous top electrode. The vertical array configuration helps to greatly increase the sensitivity of the sensor while the pores in the top electrode layer significantly improve sensing response times by allowing analyte gases to pass through freely. Herein, we show highly sensitive detection to both nitrogen dioxide (NO(2)) and ammonia (NH(3)) in humidified air. NO(2) detection down to 10 parts per billion (ppb) is demonstrated and an order-of-magnitude improvement in sensor response time is shown in the detection of NH(3). PMID:21817785

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

2011-09-01

340

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

PubMed Central

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

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

2015-01-01

341

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

PubMed

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

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

2015-01-01

342

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

NASA Astrophysics Data System (ADS)

The highly sensitive giant magneto-impedance effect in a solenoid containing a magnetic core of Fe36Co36Nb4Si4.8B19.2 (FeCo-based) ribbon under a weak magnetic field (WMF) is presented in this paper. The FeCo-based amorphous ribbon is prepared by single roller quenching and annealed with Joule heat in a flowing nitrogen atmosphere. The giant magnetoimpedance effect in solenoid (GMIES) profiles are measured with an HP4294A impedance analyzer. The result shows that the GMIES responds to the WMF sensitively (as high as 1580 %/A·m-1). The high sensitivity can be obtained in a moderate narrow range of annealing current density (30-34 A/mm2) and closely depends on the driven current frequency. The highest sensitivity (1580 %/A·m-1) is obtained when the FeCo-based amorphous ribbon is annealed at 32 A/mm2 for 10 min and then driven with an alterning current (AC) at the frequency of 350 kHz. The highly sensitive GMIES under the WMF may result from the multiple magnetic-anisotropic structure, which is induced by the temperature gradient produced during Joule-heating the ribbon.

Fang, Yun-Zhang; Xu, Qi-Ming; Zheng, Jin-Ju; Wu, Feng-Min; Ye, Hui-Qun; Si, Jian-Xiao; Zheng, Jian-Long; Fan, Xiao-Zhen; Yang, Xiao-Hong

2012-03-01

343

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

NASA Technical Reports Server (NTRS)

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.

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

1994-01-01

344

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

Microsoft Academic Search

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

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

2007-01-01

345

RAD51C-deficient cancer cells are highly sensitive to the PARP inhibitor olaparib.  

PubMed

A PARP inhibitor is a rationally designed targeted therapy for cancers with impaired DNA repair abilities. RAD51C is a paralog of RAD51 that has an important role in the DNA damage response. We found that cell lines sensitive to a novel oral PARP inhibitor, olaparib, had low levels of RAD51C expression using microarray analysis, and we therefore hypothesized that low expression of RAD51C may hamper the DNA repair process, resulting in increased sensitivity to olaparib. Compared with the cells with normal RAD51C expression levels, RAD51C-deficient cancer cells were more sensitive to olaparib, and a higher proportion underwent cell death by inducing G2-M cell-cycle arrest and apoptosis. The restoration of RAD51C in a sensitive cell line caused attenuation of olaparib sensitivity. In contrast, silencing of RAD51C in a resistant cell line enhanced the sensitivity to olaparib, and the number of RAD51 foci decreased with ablated RAD51C expression. We also found the expression of RAD51C was downregulated in cancer cells due to epigenetic changes and RAD51C expression was low in some gastric cancer tissues. Furthermore, olaparib significantly suppressed RAD51C-deficient tumor growth in a xenograft model. In summary, RAD51C-deficient cancer cells are highly sensitive to olaparib and offer preclinical proof-of-principle that RAD51C deficiency may be considered a biomarker for predicting the antitumor effects of olaparib. PMID:23512992

Min, Ahrum; Im, Seock-Ah; Yoon, Young-Kwang; Song, Sang-Hyun; Nam, Hyun-Jin; Hur, Hyung-Seok; Kim, Hwang-Phill; Lee, Kyung-Hun; Han, Sae-Won; Oh, Do-Youn; Kim, Tae-You; O'Connor, Mark J; Kim, Woo-Ho; Bang, Yung-Jue

2013-06-01

346

Optical transitions in highly charged californium ions with high sensitivity to variation of the fine-structure constant.  

PubMed

We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, ?. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf(16+) is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf(16+) has very large nuclear charge and large ionization energy, resulting in the largest ? sensitivity seen in atomic systems. The lines include positive and negative shifters. PMID:23006353

Berengut, J C; Dzuba, V A; Flambaum, V V; Ong, A

2012-08-17

347

Optical Transitions in Highly Charged Californium Ions with High Sensitivity to Variation of the Fine-Structure Constant  

NASA Astrophysics Data System (ADS)

We study electronic transitions in highly charged Cf ions that are within the frequency range of optical lasers and have very high sensitivity to potential variations in the fine-structure constant, ?. The transitions are in the optical range despite the large ionization energies because they lie on the level crossing of the 5f and 6p valence orbitals in the thallium isoelectronic sequence. Cf16+ is a particularly rich ion, having several narrow lines with properties that minimize certain systematic effects. Cf16+ has very large nuclear charge and large ionization energy, resulting in the largest ? sensitivity seen in atomic systems. The lines include positive and negative shifters.

Berengut, J. C.; Dzuba, V. A.; Flambaum, V. V.; Ong, A.

2012-08-01

348

High temperature sensitivity is intrinsic to voltage-gated potassium channels  

PubMed Central

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

Yang, Fan; Zheng, Jie

2014-01-01

349

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

NASA Astrophysics Data System (ADS)

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.

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

350

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

PubMed

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. PMID:25557614

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

351

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

SciTech Connect

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.

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

352

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

NASA Technical Reports Server (NTRS)

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

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

2003-01-01

353

Circularly polarized light with high degree of circularity and low azimuthal error sensitivity.  

PubMed

The generation of circularly polarized light with a high circularity degree and low azimuthal error sensitivity was analyzed using a system composed by two waveplates. It is shown how the high circularity degree is achieved using a combination of a half- (?/2) and a quarter- (?/4) waveplate ?/2+?/4 configuration. However, the lowest azimuthal sensitivity under small variations in the azimuths of the waveplates is obtained by employing a ?/4+?/2 configuration. Analytical calculus particularized for quartz and MgF? waveplates is presented. PMID:24922413

Vilas, Jose Luis; Bernabeu, Eusebio; Sanchez-Brea, Luis Miguel; Espinosa-Luna, Rafael

2014-06-01

354

A high sensitivity humidity sensor based on micro-ring resonator with three coupling points  

NASA Astrophysics Data System (ADS)

A novel high sensitivity humidity sensor based on micro-ring resonator with three coupling points (MRRTCP) is reported. Since the dielectric constant of Polyimide is highly sensible to the relative humidity of the environment, we choose the Polyimide (PI) as the moisture material. The effective refractive index of the sensing part of the sensor changes as the relative humidity of the environment changes, this leading to an obvious shift of the output spectrum. The sensing range of the relative humidity sensor is 0~100%RH, and the sensitivity is 0.0017?m/%RH, and the structure is relatively simple and could be used in micro-scale humidity sensing.

Guo, Shi-liang; Wang, Wen-juan; Hu, Chun-hai

2014-12-01

355

Fabrication of elliptic microfibers with CO2 laser for high-sensitivity refractive index sensing.  

PubMed

We propose a convenient method for achieving highly birefringent (HiBi) elliptic microfibers by use of the CO2-laser machining and the flame-brushing techniques. With optimization of fabrication process, a high birefringence of up to 2.10×10(-2) is experimentally obtained. Especially, within a polarization Sagnac interferometer acting as a refractive index (RI) sensor, both positive and abnormal negative sensitivity is measured, dependent on the geometrical variables of the HiBi microfiber. The maximum RI sensitivity is ?195,348??nm/RI-unit around RI=1.35887, which is the highest among the microfiber devices as reported, to our knowledge. PMID:24978529

Sun, Li-Peng; Li, Jie; Gao, Shuai; Jin, Long; Ran, Yang; Guan, Bai-Ou

2014-06-15

356

Real-time, single-step bioassay using nanoplasmonic resonator with ultra-high sensitivity  

DOEpatents

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.

Zhang, Xiang; Ellman, Jonathan A; Chen, Fanqing Frank; Su, Kai-Hang; Wei, Qi-Huo; Sun, Cheng

2014-04-01

357

High-sensitivity temperature sensor based on an alcohol-filled photonic crystal fiber loop mirror.  

PubMed

A compact temperature sensor based on a fiber loop mirror (FLM) combined with an alcohol-filled high-birefringence photonic crystal fiber (PCF) is proposed and experimentally demonstrated. The output of the FLM is an interference spectrum with many resonant dips, of which the wavelengths are quite sensitive to the change of the refractive index of the filled alcohol for the interference of the FLM. Simulation analysis predicts a high temperature sensitivity, and experimental results show it reaches up to 6.6 nm/°C for the 6.1-cm-long PCF used in the FLM. PMID:21540923

Qian, Wenwen; Zhao, Chun-Liu; He, Shaoling; Dong, Xinyong; Zhang, Shuqin; Zhang, Zaixuan; Jin, Shangzhong; Guo, Jiangtao; Wei, Huifeng

2011-05-01

358

High potential sensitivity in heterodyne amplitude-modulation Kelvin probe force microscopy  

NASA Astrophysics Data System (ADS)

A surface potential measurement method using amplitude-modulation and heterodyne techniques is proposed. The effect of the stray capacitance between a cantilever and a sample in Kelvin probe force microscopy and the electrostatic force spectroscopy measurements are almost completely removed, because the distance (z) dependence of the modulated electrostatic force increases from 1/z to1/z2. This method improves the sensitivity of short range forces and reduces the surface potential measurement crosstalk that is induced by topographic feedback. This method has the advantage of high potential sensitivity due to the high cantilever Q value under vacuum. Quantitative surface potential measurements are demonstrated.

Sugawara, Yasuhiro; Kou, Lili; Ma, Zongmin; Kamijo, Takeshi; Naitoh, Yoshitaka; Jun Li, Yan

2012-05-01

359

Highly sensitive colorimetric detection of 17?-estradiol using split DNA aptamers immobilized on unmodified gold nanoparticles.  

PubMed

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

Liu, Jinchuan; Bai, Wenhui; Niu, Shucao; Zhu, Chao; Yang, Shuming; Chen, Ailiang

2014-01-01

360

Highly sensitive colorimetric detection of 17?-estradiol using split DNA aptamers immobilized on unmodified gold nanoparticles  

PubMed Central

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

Liu, Jinchuan; Bai, Wenhui; Niu, Shucao; Zhu, Chao; Yang, Shuming; Chen, Ailiang

2014-01-01

361

A Highly Sensitive Refractometric Sensor Based on Cascaded SiN Microring Resonators  

PubMed Central

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

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

2013-01-01

362

The nature and nurture of high IQ: an extended sensitive period for intellectual development.  

PubMed

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

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

363

High-Sensitivity Troponin T: A Biomarker for Diuretic Response in Decompensated Heart Failure Patients  

PubMed Central

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

Santos, Mário; Almeida, Sofia; Marques, Irene; Bettencourt, Paulo; Carvalho, Henrique

2014-01-01

364

A Highly Sensitive Fiber Optic Sensor Based on Two-Core Fiber for Refractive Index Measurement  

PubMed Central

A simple and compact fiber optic sensor based on a two-core fiber is demonstrated for high-performance measurements of refractive indices (RI) of liquids. In order to demonstrate the suitability of the proposed sensor to perform high-sensitivity sensing in a variety of applications, the sensor has been used to measure the RI of binary liquid mixtures. Such measurements can accurately determine the salinity of salt water solutions, and detect the water content of adulterated alcoholic beverages. The largest sensitivity of the RI sensor that has been experimentally demonstrated is 3,119 nm per Refractive Index Units (RIU) for the RI range from 1.3160 to 1.3943. On the other hand, our results suggest that the sensitivity can be enhanced up to 3485.67 nm/RIU approximately for the same RI range. PMID:24152878

Guzmán-Sepúlveda, José Rafael; Guzmán-Cabrera, Rafael; Torres-Cisneros, Miguel; Sánchez-Mondragón, José Javier; May-Arrioja, Daniel Alberto

2013-01-01

365

Highly Sensitive and Fast Anion-Selective InN Quantum Dot Electrochemical Sensors  

NASA Astrophysics Data System (ADS)

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.

Hassan Alvi, Naveed ul; Rodriguez, Paul E. D. Soto; Gómez, Victor J.; Kumar, Praveen; Willander, Magnus; Nötzel, Richard

2013-11-01

366

High-frequency stimulation of the hippocampus blocks fear learning sensitization and return of extinguished fear.  

PubMed

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

Deschaux, O; Koumar, O-C; Canini, F; Moreau, J-L; Garcia, R

2015-02-12

367

A fast, highly sensitive double-nested PCR-based method to screen fish immunobiomes  

E-print Network

A fast, highly sensitive double-nested PCR-based method to screen fish immunobiomes SE´ BASTIEN samples. Here we have developed a double-nested PCR method- ology that generates 16S tag amplicon populations. The double-nested PCR efficiency was compared with two other PCR strategies: single primer pair

Bernatchez, Louis

368

HIGH SENSITIVITY ACOUSTIC TRANSDUCERS WITH THIN P+ MEMBRANES AND GOLD BACK-PLATE  

E-print Network

pressure sensors have been reported in literature. Acoustic transducers, which can be considered a special class of pressure sensors, have been made in silicon. The key features of introducing silicon technology1 1 HIGH SENSITIVITY ACOUSTIC TRANSDUCERS WITH THIN P+ MEMBRANES AND GOLD BACK-PLATE A. E. Kabir, R

Bashir, Rashid

369

Constructing a High-Sensitivity, Computer-Interfaced, Differential Thermal Analysis Device for Teaching and Research  

ERIC Educational Resources Information Center

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.

Martinez, L. M.; Videa, M.; Mederos, F.; Mesquita, J.

2007-01-01

370

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

371

A Simple and Highly Sensitive Colorimetric Detection Method for Gaseous Formaldehyde  

E-print Network

A Simple and Highly Sensitive Colorimetric Detection Method for Gaseous Formaldehyde Liang Feng inexpensive colorimetric methods, which see some field use.5 A number of colorimetric or fluorometric methods colorimetric method for fast formaldehyde detection. Most colorimetric formaldehyde detection methods are based

Suslick, Kenneth S.

372

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

PubMed

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

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

2013-01-01

373

Highly Sensitive and Rapid Detection of Antibody Catalysis by Luminescent Bacteria  

E-print Network

allowed for ¯uorescence detection on TLC plates.7 Intact marine bioluminescent bacteria provideHighly Sensitive and Rapid Detection of Antibody Catalysis by Luminescent Bacteria Hagit Shulman, and facile bioluminescent assay for the detection of catalytic antibodies has been devel- oped. This assay

Keinan, Ehud

374

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

E-print Network

of the quantum efficiency of the solar cells. The power conversion efficiency of the solar cell is increased to 6A highly efficient (>6%) Cd1Ã?xMnxSe quantum dot sensitized solar cell Jianjun Tian,*a Lili Lv,12,13 Improving the power conversion efficiency (h) of QDSCs has always been an overarching concern for all

Cao, Guozhong

375

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

NASA Astrophysics Data System (ADS)

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

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

2013-01-01

376

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. ...

377

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

E-print Network

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

Chen, Ray

378

Highly Sensitive Measurement of Doppler-Shift with a Microchip Solid-State Laser  

Microsoft Academic Search

Intensity modulation of a LiNdP4O12 microchip solid-state laser by reflected scattered light from a moving object is investigated experimentally and numerically. Ultra-high sensitivity detection of Doppler-shift and application to a laser velocity meter are demonstrated.

Kenju Otsuka

1992-01-01

379

High-sensitivity vibrational imaging with frequency modulation coherent anti-Stokes  

E-print Network

High-sensitivity vibrational imaging with frequency modulation coherent anti-Stokes Raman vibrational os- cillators than possible through existing CARS microscopy methods. © 2006 Optical Society information about the intrinsic vibrational resonances of a sample, allowing for label-free, chemically

Xie, Xiaoliang Sunney

380

Transgenic elimination of high-affinity antidepressant and cocaine sensitivity in the presynaptic  

E-print Network

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

Blakely, Randy

381

PCR detection of nearly any dengue virus strain using a highly sensitive primer `cocktail'  

E-print Network

PCR detection of nearly any dengue virus strain using a highly sensitive primer `cocktail' Charul to target effectively. This problem is espe- cially pronounced with the mutation-prone RNA viruses. Dengue Keywords cocktail PCR; dengue virus; diagnostic; PCR; primer Correspondence R. C. Willson, Department

Fox, George

382

A Diode Laser Chemical Sensor Utilizing an Oxidized Lower Cladding Layer for High Sensitivity  

E-print Network

A Diode Laser Chemical Sensor Utilizing an Oxidized Lower Cladding Layer for High Sensitivity Chad@engineering.ucsb.edu Tel: 805.893.7065 Abstract: We demonstrate a novel chemical sensor incorporating a symmetrically-clad clad, and have tight optical confinement [4]. Symmetrically clad dielectric waveguides have been

Coldren, Larry A.

383

Highly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy  

E-print Network

to stably bond monolayers of an iron heme complex onto silicon that enables direct, quantitative detectionHighly Sensitive Nitric Oxide Detection Using X-ray Photoelectron Spectroscopy Manish Dubey, Steven and direct detection of NO at these levels is important. NO is also a decomposition product of several

Schwartz, Jeffrey

384

A delay line with highly linear thermal sensitivity for smart temperature sensor  

Microsoft Academic Search

A highly linear thermal sensitivity delay line for smart temperature sensor is presented. The proposed delay line is a current starved inverter chain. A simple bias current source circuit is incorporated with the delay line to generate a current inversely proportional to temperature based on the transconductance characteristics of a MOS device at the vicinity of the zero temperature coefficient

Nguyen Thanh Trung; Kwansu Shon; Soo-Won Kim

2007-01-01

385

Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts  

E-print Network

Stable and highly sensitive gas sensors based on semiconducting oxide nanobelts E. Comini, G for publication 16 July 2002 Gas sensors have been fabricated using the single-crystalline SnO2 nanobelts of the gas, is 4160% for 250 ppm of ethanol and 1550% for 0.5 ppm NO2 at 400 °C. The results demonstrate

Wang, Zhong L.

386

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

E-print Network

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

Bentz, Dale P.

387

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

PubMed

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

Wilhelm, C J; Mitchell, S H

2008-10-01

388

High Sensitivity GPS Velocity Updates For Personal Indoor Navigation Using Inertial  

E-print Network

High Sensitivity GPS Velocity Updates For Personal Indoor Navigation Using Inertial Navigation been working in the area of satellite and inertial navigation since receiving his BSc from the same extensively on the integration of GPS and inertial navigation systems for precise aircraft positioning. Dr

Calgary, University of

389

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

PubMed

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

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

2014-08-01

390

GATE Monte Carlo Simulation of a High-Sensitivity and High-Resolution LSO-Based Small Animal PET Camera  

Microsoft Academic Search

In this paper, we describe a Monte Carlo simulation of the performance of a high-sensitivity and high-resolution small animal positron emission tomography (PET) scanner with a large axial fleld-of-view (AFOV). The simulated camera is based on the photomultiplier-quadrant-sharing (PQS) concept and composed of 180 blocks of 14 times 14 lutetium oxyorthosilicate (LSO) crystals each measuring 1.16 mm transaxially, 1.27 mm

Hossain Baghaei; Yuxuan Zhang; Hongdi Li; Yu Wang; Soonseok Kim; Rocio A. Ramirez; Jiguo Liu; Shitao Liu; Wai-Hoi Wong

2007-01-01

391

A high sensitivity wireless mass-loading surface acoustic wave DNA biosensor  

NASA Astrophysics Data System (ADS)

In this paper, a surface acoustic wave (SAW) biosensor with gold delay area on LiNbO3 substrate detecting DNA sequences is proposed. By well-designed device parameters of the SAW sensor, it achieves a high performance for highly sensitive detection of target DNA. In addition, an effective biological treatment method for DNA immobilization and abundant experimental verification of the sensing effect have made it a reliable device in DNA detection. The loading mass of the probe and target DNA sequences is obtained from the frequency shifts, which are big enough in this work due to an effective biological treatment. The experimental results show that the biosensor has a high sensitivity of 1.2 pg/ml/Hz and high selectivity characteristic is also verified by the few responses of other substances. In combination with wireless transceiver, we develop a wireless receiving and processing system that can directly display the detection results.

Cai, Hua-Lin; Yang, Yi; Zhang, Yi-Han; Zhou, Chang-Jian; Guo, Cang-Ran; Liu, Jing; Ren, Tian-Ling

2014-03-01

392

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

PubMed

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

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

2014-05-27

393

High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range  

NASA Astrophysics Data System (ADS)

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.

Lin, Tingting; Zhang, Yi; Lee, Yong-Ho; Krause, Hans-Joachim; Lin, Jun; Zhao, Jing

2014-11-01

394

High-sensitivity cooled coil system for nuclear magnetic resonance in kHz range.  

PubMed

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

Lin, Tingting; Zhang, Yi; Lee, Yong-Ho; Krause, Hans-Joachim; Lin, Jun; Zhao, Jing

2014-11-01

395

A high-sensitivity search for extraterrestrial intelligence at lambda 18 CM  

Microsoft Academic Search

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

J. Tarter; J. Cuzzi; D. Black; T. Clark

1980-01-01

396

Label-free highly sensitive detection of (small) molecules by wavelength interrogation of integrated optical chips  

Microsoft Academic Search

A bio-chemical sensor system based on wavelength interrogation of integrated optical sensor chips is presented. The combination of a non-mechanical scanning approach with sensor chips of high quality and stability allows fast and accurate multi-channel measurements. The emphasis of the present paper lies in presenting detailed design considerations, and in reporting the application of the system to several high sensitivity

K. Cottier; M. Wiki; G. Voirin; H. Gao; R. E. Kunz

2003-01-01

397

Sensitization of High-Nitrogen Austenitic Stainless Steels by Dichromium Nitride Precipitation  

Microsoft Academic Search

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

J. W. Simmons; J. C. Rawers; D. G. Atteridge

1994-01-01

398

Long-term sensitivity of a High Arctic wetland to Holocene climate change  

Microsoft Academic Search

Summary 1 The response of peat-rich permafrost soils to human-induced climate change may be especially important in modifying the global C-flux. We examined the Holocene developmental record of a High Arctic peat-forming wetland to investigate its sensitivity to past climate change and aid understanding of the likely effects of future climate warming on high-latitude ecosystems. 2 The microhabitat of mosses

CHRISTOPHER J. ELLIS; LINE ROCHEFORT

2006-01-01

399

A novel light tracing system with high-precision and high-sensitivity sensors setup  

NASA Astrophysics Data System (ADS)

This paper presents a novel light source tracing system, which is comprised of a light-tracing board, with four photo-sensors of different incline angles, correspondingly disposed on its four edges, which are adjustable according to the movement range of the light source in order to achieve light-tracing purposes. This system introduces the algorithm of four-edge-sensors with servo motors in each site to improve sensor's sensitivity. The measurement values of light perception can be feedback to the programmable logic controller by wireless transceiver module. After proportional-integral-derivative operation, the system can obtain the situation of light source. In a normal mode, the light source movement range is large, the range of the incline angle of the light sensors are also set to large to obtain wide detection angle. But in a locking mode, the incline angle of the light sensing plane decreases, thus, the measurement range reduces, and the sensitivity is higher.

Lin, Chern-Sheng; Wu, Pin Yi; Tsai, Jen Min; Tseng, Yu Hung; Chen, Hsin-Hung; Hwang, Jiann-Lih

2013-11-01

400

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

PubMed Central

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

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

2014-01-01

401

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

NASA Technical Reports Server (NTRS)

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

Wilcox, Mike

1993-01-01

402

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

PubMed

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

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

2014-10-01

403

High sensitivity to humidity of an element based on a carbon-nanotube bundle  

NASA Astrophysics Data System (ADS)

The results of development and studies of humidity-sensitive elements based on a carbon-nanotube bundle are presented. It has been demonstrated that arrays of nanotubes grown by the low-temperature plasma-chemical method on planar silicon structures have exceptional sensitivity to humidity. The ratio of the structure resistance in dry and humid states is more than 105-fold. Such a high relative resistance change is caused by the character of changes in conductivity of the charge carriers between individual tubes of the bundle upon adsorption of water molecules.

Bulyarskii, S. V.; Basaev, A. S.; Gal'perin, A. V.; Ermakov, M. S.; Pavlov, A. A.; Shaman, Yu. P.

2013-10-01

404

A sensitive assay method of furosemide in plasma and urine by high-performance liquid chromotography.  

PubMed

A sensitive assay method of furosemide in plasma and urine by high-performance liquid chromatography (HPLC) is described. The minimum measurable concentrations of furosemide in plasma and urine were 0.2 and 5.0 microgram/ml, respectively; whereas the coefficients of variation of furosemide levels were found to be 7.8% for plasma and 2.0% for urine. These are within the acceptably low limits. Hence, the present method of furosemide is sensitive, reproducible, and accurate for therapeutic drug monitoring. The significance of this HPLC assay method is discussed. PMID:7157461

Snedden, W; Sharma, J N; Fernandez, P G

1982-01-01

405

Polymer-coated symmetrical metal-cladding waveguide for chemical vapor detection with high sensitivity  

NASA Astrophysics Data System (ADS)

An optical platform for sensitive detection of chemical vapor based on a polymer-coated symmetrical metal-cladding waveguide is proposed. The diffusion of chemical vapor usually leads to a combinational effect in the polymer layer, i.e., swelling and refractive index change. Owing to the high sensitivity of ultrahigh-order modes, the vapor-induced effect will give rise to a dramatic variation of the reflected light intensity. For proof-of-concept, a good linearity and a low detection limit of toluene and benzene are experimentally demonstrated with an amorphous Teflon AF polymer layer.

Xiao, PingPing; Deng, ManLan

2012-11-01

406

A high sensitivity hall sensor fabricated on a SOI wafer using surface micromachining technique  

NASA Astrophysics Data System (ADS)

Hall sensors of high sensitivity have been designed and fabricated using the Micro-Electro-Mechanical System (MEMS) process. This paper presents the design and fabrication techniques used to obtain high sensitivity Hall sensors on a thin film polyimide flexible substrate. The devices are fabricated on a Silicon-on-Insulator (SOI), with boron-doped p-type Silicon as the active layer, using surface micromachining principles. The arrays of Hall devices are further transferred to a flexible substrate using a combination of wet and dry micromachining processes. The manufactured devices are stable over a range of temperature displaying relatively high magnetic sensitivity values. The recorded device sensitivities are in the range of 10?V/mA-G. The fabrication process aims at fabricating devices on a flexible substrate that enables to curve the Hall probes and thus use them for the measurement of radial magnetic fields and magnetic fields on curved surfaces. The volume of the active region is 1000×100×2?m.

Singh, Namit; Estrada, Horacio V.

2009-02-01

407

Chemostat-like microfluidic platform for highly sensitive detection of heavy metal ions using microbial biosensors.  

PubMed

Reporter-gene-based microbial biosensors have high potential for detecting small molecules, including heavy metal ions (HMIs), in a sensitive and selective manner by involving low costs. However, the sensitivity and dynamic range of the sensing mechanism are largely limited by the conventional culture environment that relies on the batch-type addition of the small molecules in nutrients and the subsequent genetic induction of sensing microbes. Here, we describe a high-throughput, chemostat-like microfluidic platform that can continuously supply both nutrients and inducers (HMIs) using microfabricated ratchet structures and a mixing microchannel network. We found that the microfluidic platform not only allowed microbial biosensors to be highly concentrated in a detection microchamber array but also enabled them to continuously grow and control synthetic genetic circuits in response to heavy metals. We also demonstrated that the combination of the platform and microbial biosensors enhanced the sensitivity for detecting divalent lead and cadmium ions by approximately three orders of magnitude relative to conventional batch-type methods. Because the platform is portable and only requires small sample volumes and fluorescent detection, the chemostat-like microfluidic platform in conjunction with microbial biosensors could be widely utilized to facilitate the specific and sensitive detection of molecular analytes on a chip. PMID:25461167

Kim, Minseok; Lim, Ji Won; Kim, Hyun Ju; Lee, Sung Kuk; Lee, Sang Jun; Kim, Taesung

2014-10-18

408

A gyroscope fabrication method for high sensitivity and robustness to fabrication tolerances  

NASA Astrophysics Data System (ADS)

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].

Sung, Jungwoo; Kim, Jin Young; Seok, Seyeong; Kwon, Hyuckjin J.; Kim, Minseo; Kim, Geonhwee; Lim, Geunbae

2014-07-01

409

High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors  

NASA Astrophysics Data System (ADS)

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.

Andersen, T.; Jensen, R.; Christensen, M. K.; Pedersen, T.; Hansen, O.; Chorkendorff, I.

2012-07-01

410

High mass resolution time of flight mass spectrometer for measuring products in heterogeneous catalysis in highly sensitive microreactors  

SciTech Connect

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}.

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

411

Highly sensitive optical fiber oxygen sensor based on dye entrapped core-shell silica nanoparticles  

NASA Astrophysics Data System (ADS)

This paper presents a highly-sensitive oxygen sensor that comprises an optical fiber coated at one end with platinum (II) meso-tetrakis (pentrafluorophenyl)porphine (PtTFPP) and PtTFPP entrapped core-shell silica nanaparticles embedded in an n-octyltriethoxysilane (Octyl-triEOS)/tetraethylorthosilane (TEOS) composite xerogel. The sensitivity of the optical oxygen sensor is quantified in terms of the ratio I0/I100, where I0 and I100 represent the detected fluorescence intensities in pure nitrogen and pure oxygen environments, respectively. The experimental results reveal that the oxygen sensor has a sensitivity of 166. The response time was 1.3 s when switching from pure nitrogen to pure oxygen, and 18.6 s when switching in the reverse direction.

Chu, Chen-Shane; Lo, Yu-Lung; Sung, Ti-Wen

2011-05-01

412

Portable and High-Sensitive Apparatus for Measurement of Environmental Radon Using CR-39 Track Detector  

NASA Astrophysics Data System (ADS)

Highly sensitive, electrostatic collection chambers have been developed for low-level radon measurements using CR-39 plastic track detectors. Chambers with outer electrodes shaped as a cone and a hemisphere with lines of electric force that were focused on the center of the collector electrode gave alpha-track distributions similar to a 2-dimensional Gaussian with a FWHM of less than 3 mm. The sensitivities, defined as the track density for a radon exposure of 1 Bq h/m3, were more than 4 tracks/cm2 using a chamber with a volume of about 300 cm3. The dependencies of the sensitivity and the track distribution on the collector voltage and humidity were investigated.

Miyake, Hiroshi; Oda, Keiji; Michijima, Masami

1987-04-01

413

Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes  

NASA Astrophysics Data System (ADS)

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.

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

2013-06-01

414

Large area CMOS bio-pixel array for compact high sensitive multiplex biosensing.  

PubMed

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

Sandeau, Laure; Vuillaume, Cassandre; Contié, Sylvain; Grinenval, Eva; Belloni, Federico; Rigneault, Hervé; Owens, Roisin M; Fournet, Margaret Brennan

2014-12-10

415

A sensitive, high resolution magic angle turning experiment for measuring chemical shift tensor principal values  

NASA Astrophysics Data System (ADS)

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.

Alderman, D. W.

1998-12-01

416

Highly Sensitive and Selective Gas Sensor Using Hydrophilic and Hydrophobic Graphenes  

PubMed Central

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

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

2013-01-01

417

Ultra-sensitive high-density Rb-87 radio-frequency magnetometer  

SciTech Connect

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.

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

418

Gold nanoparticle thin films fabricated by electrophoretic deposition method for highly sensitive SERS application  

NASA Astrophysics Data System (ADS)

We report an electrophoretic deposition method for the fabrication of gold nanoparticle (GNP) thin films as sensitive surface-enhanced Raman scattering (SERS) substrates. In this method, GNP sol, synthesized by a seed-mediated growth approach, and indium tin oxide (ITO) glass substrates were utilized as an electrophoretic solution and electrodes, respectively. From the scanning electron microscopy analysis, we found that the density of GNPs deposited on ITO glass substrates increases with prolonged electrophoresis time. The films possess high mechanical adhesion strength and exhibit strong localized surface plasmon resonance (LSPR) effect by showing high SERS sensitivity to detect 1 × 10-7 M rhodamine 6 G in methanol solution. Finally, the relationship between Raman signal amplification capability and GNP deposition density has been further investigated. The results of our experiment indicate that the high-density GNP film shows relatively higher signal amplification capability due to the strong LSPR effect in narrow gap regions between the neighboring particles on the film.

Zhu, Sheng-Qing; Zhang, Tong; Guo, Xin-Li; Wang, Qi-Long; Liu, Xuefeng; Zhang, Xiao-Yang

2012-11-01

419

Proposed configurations for a high-repetition-rate position-sensitive atom probe  

NASA Astrophysics Data System (ADS)

We consider the means available for dramatically increasing the data collection rate and mass resolution for position-sensitive atom probes. We conclude that thermal pulsing offers the best opportunity for improving these parameters. Pulsed electron beams can provide the thermal pulses, but will require very high current densities in small probes. Pulsed photon beam systems focused with reflecting objectives offer higher performance and simpler construction than existing laser pulsing systems. A position-sensitive detector using a wedge-and-strip anode, multichannel plates, and high-speed electronics provides necessary speed and resolution for single events. Hybrid multi-element detectors with integrated charge separation electronics handle multiple events at high repetition rates. Aquisition rates of 10 6 atoms per second should be achievable with systems incorporating these design elements.

Kelly, Thomas F.; Mancini, Derrick C.; McCarthy, Jon J.; Zreiba, Nuri A.

1991-04-01

420

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

SciTech Connect

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

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

2013-12-30

421

High sensitivity beam emission spectroscopy for core plasma turbulence imaging (invited)  

SciTech Connect

An upgraded beam emission spectroscopy (BES) diagnostic has been developed and deployed at the DIII-D tokamak to achieve a dramatic increase in sensitivity to small-scale density fluctuations. This upgraded BES diagnostic system incorporates high-throughput silica optical fiber bundles (1.62 mm{sup 2}-ster per channel), ultra fast spectrometer collection optics, custom-designed high-transmission interference filters, and large-area photodiodes. The fiber bundle images are optimized to match measured radial and poloidal asymmetries of turbulent eddies. These enhancements result in an approximately one order of magnitude increase in measured beam emission signal. As a consequence of the relative contributions of photon and electronic noise, the net increase in sensitivity to plasma density fluctuation power ranges from ten to 30, allowing for the observation of small-amplitude (n-tilde sign/n{>=}0.1%) density fluctuations associated with turbulence and energetic particle modes in the core of high-performance discharges. An array of 16 BES channels has been arranged in a 4x4 grid to provide modest-field (3.2x5 cm), high-sensitivity imaging capability that extends over multiple turbulence correlation lengths. This diagnostic capability allows for the first direct imaging of turbulence in the core region of low-confinement and high-confinement tokamak plasmas.

McKee, G. R.; Fonck, R. J.; Gupta, D. K.; Schlossberg, D. J.; Shafer, M. W.; Boivin, R. L. [University of Wisconsin-Madison, 1500 Engineering Dr., Madison, Wisconsin (United States); General Atomics, San Diego, California (United States)

2006-10-15

422

High Sensitivity Combined with Extended Structural Coverage of Labile Compounds via Nanoelectrospray Ionization at Subambient Pressures  

SciTech Connect

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. ?

Cox, Jonathan T.; Kronewitter, Scott R.; Shukla, Anil K.; Moore, Ronald J.; Smith, Richard D.; Tang, Keqi

2014-10-07

423

High-Sensitivity Atomic Magnetometer Unaffected by Spin-Exchange Relaxation J. C. Allred and R. N. Lyman  

E-print Network

High-Sensitivity Atomic Magnetometer Unaffected by Spin-Exchange Relaxation J. C. Allred and R. N; published 9 September 2002) Alkali-metal magnetometers compete with SQUID detectors as the most sensitive magnetic field sensors. Their sensitivity is limited by relaxation due to spin-exchange collisions. We

Romalis, Mike

424

The Sensitivity of HAWC to High-Mass Dark Matter Annihilations  

E-print Network

The High Altitude Water Cherenkov (HAWC) observatory is a wide field-of-view detector sensitive to gamma rays of 100 GeV to a few hundred TeV. Located in central Mexico at 19 degrees North latitude and 4100 m above sea level, HAWC will observe gamma rays and cosmic rays with an array of water Cherenkov detectors. The full HAWC array is scheduled to be operational in 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.