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Sample records for hybrid triple-quadrupole linear

  1. Comparison of triple quadrupole, hybrid linear ion trap triple quadrupole, time-of-flight and LTQ-Orbitrap mass spectrometers in drug discovery phase metabolite screening and identification in vitro--amitriptyline and verapamil as model compounds.

    Science.gov (United States)

    Rousu, Timo; Herttuainen, Jukka; Tolonen, Ari

    2010-04-15

    Liquid chromatography in combination with mass spectrometry (LC/MS) is a superior analytical technique for metabolite profiling and identification studies performed in drug discovery and development laboratories. In the early phase of drug discovery the analytical approach should be both time- and cost-effective, thus providing as much data as possible with only one visit to the laboratory, without the need for further experiments. Recent developments in mass spectrometers have created a situation where many different mass spectrometers are available for the task, each with their specific strengths and drawbacks. We compared the metabolite screening properties of four main types of mass spectrometers used in analytical laboratories, considering both the ability to detect the metabolites and provide structural information, as well as the issues related to time consumption in laboratory and thereafter in data processing. Human liver microsomal incubations with amitriptyline and verapamil were used as test samples, and early-phase 'one lab visit only' approaches were used with all instruments. In total, 28 amitriptyline and 69 verapamil metabolites were found and tentatively identified. Time-of-flight mass spectrometry (TOFMS) was the only approach detecting all of them, shown to be the most suitable instrument for elucidating as comprehensive metabolite profile as possible leading also to lowest overall time consumption together with the LTQ-Orbitrap approach. The latter however suffered from lower detection sensitivity and false negatives, and due to slow data acquisition rate required slower chromatography. Approaches with triple quadrupole mass spectrometry (QqQ) and hybrid linear ion trap triple quadrupole mass spectrometry (Q-Trap) provided the highest amount of fragment ion data for structural elucidation, but, in addition to being unable to produce very high-important accurate mass data, they suffered from many false negatives, and especially with the Qq

  2. Non-target screening of Allura Red AC photodegradation products in a beverage through ultra high performance liquid chromatography coupled with hybrid triple quadrupole/linear ion trap mass spectrometry.

    Science.gov (United States)

    Gosetti, Fabio; Chiuminatto, Ugo; Mazzucco, Eleonora; Calabrese, Giorgio; Gennaro, Maria Carla; Marengo, Emilio

    2013-01-15

    The study deals with the identification of the degradation products formed by simulated sunlight photoirradiation in a commercial beverage that contains Allura Red AC dye. An UHPLC-MS/MS method, that makes use of hybrid triple quadrupole/linear ion trap, was developed. In the identification step the software tool information dependent acquisition (IDA) was used to automatically obtain information about the species present and to build a multiple reaction monitoring (MRM) method with the MS/MS fragmentation pattern of the species considered. The results indicate that the identified degradation products are formed from side-reactions and/or interactions among the dye and other ingredients present in the beverage (ascorbic acid, citric acid, sucrose, aromas, strawberry juice, and extract of chamomile flowers). The presence of aromatic amine or amide functionalities in the chemical structures proposed for the degradation products might suggest potential hazards to consumer health.

  3. P202-S Expanding the Capabilities of Peptide MRM-Based Assays in Plasma Using a Hybrid Triple-Quadrupole Linear Ion-Trap Mass Spectrometer

    OpenAIRE

    Hunter, C.

    2007-01-01

    As the study of protein biomarkers increases in importance, technical limitations to the detection of low-abundance proteins and high-throughput, high-precision quantitation remain to be overcome. The complexity and dynamic range of the plasma proteome makes the task of specific, quantitative detection even more challenging. Multiple reaction monitoring (MRM) capabilities of triple quadrupole MS systems have been explored as solutions to this challenge due to their well-known sensitivity and ...

  4. A hybrid liquid chromatography-mass spectrometry strategy in a forensic laboratory for opioid, cocaine and amphetamine classes in human urine using a hybrid linear ion trap-triple quadrupole mass spectrometer.

    Science.gov (United States)

    Dowling, Geraldine; Regan, Liam; Tierney, Julie; Nangle, Michael

    2010-10-29

    A rapid method has been developed to analyse morphine, codeine, morphine-3-glucuronide, 6-monoacetylmorphine, cocaine, benzoylegonine, buprenorphine, dihydrocodeine, cocaethylene, 3,4-methylenedioxyamphetamine, ketamine, 3,4-methylenedioxymethamphetamine, pseudoephedrine, lignocaine, benzylpiperazine, methamphetamine, amphetamine, 2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine and methadone in human urine. Urine samples were diluted with methanol:water (1:1, v/v) and sample aliquots were analysed by hybrid linear ion trap-triple quadrupole mass spectrometry with a runtime of 12.5 min. Multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information-dependent acquisition (IDA) experiment. Finally, drug identification and confirmation was carried out by library search with a developed in-house MS/MS library based on EPI spectra at a collision energy spread of 35±15 in positive mode and MRM ratios. The method was validated in urine, according to the criteria defined in Commission Decision 2002/657/EC. At least two MRM transitions for each substance were monitored in addition to EPI spectra and deuterated analytes were used as internal standards for quantitation. The reporting level was 0.05 μg mL(-1) for the range of analytes tested. The regression coefficients (r(2)) for the calibration curves (0-4 μg mL(-1)) in the study were ≥0.98. The method proved to be simple and time efficient and was implemented as an analytical strategy for the illicit drug monitoring of opioids, cocaines and amphetamines in criminal samples from crime offenders, abusers or victims in the Republic of Ireland. To the best of our knowledge there are no hybrid LC-MS applications using MRM mode and product ion spectra in the linear ion trap mode for opioids, cocaines or amphetamines with validation data in urine.

  5. Evaluation of multiple reaction monitoring cubed for the analysis of tachykinin related peptides in rat spinal cord using a hybrid triple quadrupole-linear ion trap mass spectrometer.

    Science.gov (United States)

    Pailleux, Floriane; Beaudry, Francis

    2014-02-01

    Targeted peptide methods generally use HPLC-MS/MRM approaches. Although dependent on the instrumental resolution, interferences may occur while performing analysis of complex biological matrices. HPLC-MS/MRM(3) is a technique, which provides a significantly better selectivity, compared with HPLC-MS/MRM assay. HPLC-MS/MRM(3) allows the detection and quantitation by enriching standard MRM with secondary product ions that are generated within the linear ion trap. Substance P (SP) and neurokinin A (NKA) are tachykinin peptides playing a central role in pain transmission. The objective of this study was to verify whether HPLC-MS/MRM(3) could provide significant advantages over a more traditional HPLC-MS/MRM assay for the quantification of SP and NKA in rat spinal cord. The results suggest that reconstructed MRM(3) chromatograms display significant improvements with the nearly complete elimination of interfering peaks but the sensitivity (i.e. signal-to-noise ratio) was severely reduced. The precision (%CV) observed was between 3.5% and 24.1% using HPLC-MS/MRM and in the range of 4.3-13.1% with HPLC-MS/MRM(3), for SP and NKA. The observed accuracy was within 10% of the theoretical concentrations tested. HPLC-MS/MRM(3) may improve the assay sensitivity to detect difference between samples by reducing significantly the potential of interferences and therefore reduce instrumental errors.

  6. Performance Characteristics of a New Hybrid Triple Quadrupole Time-of-Flight Tandem Mass Spectrometer

    Science.gov (United States)

    Andrews, Genna L.; Simons, Brigitte L.; Young, J. Bryce; Hawkridge, Adam M.; Muddiman, David C.

    2011-01-01

    The TripleTOF 5600 System, a hybrid triple quadrupole time-of-flight mass spectrometer, was evaluated to explore the key figures of merit in generating peptide and protein identifications which included spectral acquisition rates, data quality, proteome coverage, and biological depth. Employing a Saccharomyces cerevisiae tryptic digest, careful consideration of several performance features demonstrated that the speed of the TripleTOF contributed most to the resultant data. The TripleTOF system was operated with 8, 20, and 50 MS/MS events in an effort to compare to other MS technologies and to demonstrate the abilities of the instrument platform. PMID:21619048

  7. Degradation study of enniatins by liquid chromatography-triple quadrupole linear ion trap mass spectrometry.

    Science.gov (United States)

    Serrano, A B; Meca, G; Font, G; Ferrer, E

    2013-12-15

    Enniatins A, A1, B and B1 (ENs) are mycotoxins produced by Fusarium spp. and are normal contaminants of cereals and derivate products. In this study, the stability of ENs was evaluated during food processing by simulation of pasta cooking. Thermal treatments at different incubation times (5, 10 and 15 min) and different pH (4, 7 and 10) were applied in an aqueous system and pasta resembling system (PRS). The concentrations of the targeted mycotoxins were determined using liquid chromatography coupled to tandem mass spectrometry. High percentages of ENs reduction (81-100%) were evidenced in the PRS after the treatments at 5, 10 and 15 min of incubation. In contrast to the PRS, an important reduction of the ENs was obtained in the aqueous system after 15 min of incubation (82-100%). In general, no significant differences were observed between acid, neutral and basic solutions. Finally, several ENs degradation products were identified using the technique of liquid chromatography-triple quadrupole linear ion trap mass spectrometry.

  8. A Generic Multiple Reaction Monitoring Based Approach for Plant Flavonoids Profiling Using a Triple Quadrupole Linear Ion Trap Mass Spectrometry

    Science.gov (United States)

    Yan, Zhixiang; Lin, Ge; Ye, Yang; Wang, Yitao; Yan, Ru

    2014-06-01

    Flavonoids are one of the largest classes of plant secondary metabolites serving a variety of functions in plants and associating with a number of health benefits for humans. Typically, they are co-identified with many other secondary metabolites using untargeted metabolomics. The limited data quality of untargeted workflow calls for a shift from the breadth-first to the depth-first screening strategy when a specific biosynthetic pathway is focused on. Here we introduce a generic multiple reaction monitoring (MRM)-based approach for flavonoids profiling in plants using a hybrid triple quadrupole linear ion trap (QTrap) mass spectrometer. The approach includes four steps: (1) preliminary profiling of major aglycones by multiple ion monitoring triggered enhanced product ion scan (MIM-EPI); (2) glycones profiling by precursor ion triggered EPI scan (PI-EPI) of major aglycones; (3) comprehensive aglycones profiling by combining MIM-EPI and neutral loss triggered EPI scan (NL-EPI) of major glycone; (4) in-depth flavonoids profiling by MRM-EPI with elaborated MRM transitions. Particularly, incorporation of the NH3 loss and sugar elimination proved to be very informative and confirmative for flavonoids screening. This approach was applied for profiling flavonoids in Astragali radix ( Huangqi), a famous herb widely used for medicinal and nutritional purposes in China. In total, 421 flavonoids were tentatively characterized, among which less than 40 have been previously reported in this medicinal plant. This MRM-based approach provides versatility and sensitivity that required for flavonoids profiling in plants and serves as a useful tool for plant metabolomics.

  9. Quantitative determination of multi markers in five varieties of Withania somnifera using ultra-high performance liquid chromatography with hybrid triple quadrupole linear ion trap mass spectrometer combined with multivariate analysis: Application to pharmaceutical dosage forms.

    Science.gov (United States)

    Chandra, Preeti; Kannujia, Rekha; Saxena, Ankita; Srivastava, Mukesh; Bahadur, Lal; Pal, Mahesh; Singh, Bhim Pratap; Kumar Ojha, Sanjeev; Kumar, Brijesh

    2016-09-10

    An ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry method has been developed and validated for simultaneous quantification of six major bioactive compounds in five varieties of Withania somnifera in various plant parts (leaf, stem and root). The analysis was accomplished on Waters ACQUITY UPLC BEH C18 column with linear gradient elution of water/formic acid (0.1%) and acetonitrile at a flow rate of 0.3mLmin(-1). The proposed method was validated with acceptable linearity (r(2), 0.9989-0.9998), precision (RSD, 0.16-2.01%), stability (RSD, 1.04-1.62%) and recovery (RSD ≤2.45%), under optimum conditions. The method was also successfully applied for the simultaneous determination of six marker compounds in twenty-six marketed formulations. Hierarchical cluster analysis and principal component analysis were applied to discriminate these twenty-six batches based on characteristics of the bioactive compounds. The results indicated that this method is advance, rapid, sensitive and suitable to reveal the quality of Withania somnifera and also capable of performing quality evaluation of polyherbal formulations having similar markers/raw herbs. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Rapid quantification of four major bioactive alkaloids in Corydalis decumbens (Thunb.) Pers. by pressurised liquid extraction combined with liquid chromatography-triple quadrupole linear ion trap mass spectrometry.

    Science.gov (United States)

    Shen, Yan; Han, Chao; Jiang, Yongxiang; Zhou, Xiujin; Zhu, Zhenou; Lei, Xinxiang

    2011-05-30

    A new method based on pressurised liquid extraction (PLE) followed by liquid chromatography-triple quadrupole linear ion trap mass spectrometry (LC-QTrap-MS) analysis has been developed for the identification and quantification of four major alkaloids in extracts of Corydalis decumbens (Thunb.) Pers. PLE extractions were performed using 90% ethanol; temperature was set at 100°C and pressure at 1500 psi. HPLC analysis was performed on a Waters XBridge™ C(18) column (150 mm × 2.1mm i.d., 3.5 μm) eluted by a mobile phase of acetonitrile and 0.2% acetic acid. Data acquisition was carried out in multiple reaction monitoring transitions (MRMs) mode, monitoring two MRM transitions to ensure an accurate identification of target compounds in the samples. Additional identification and confirmation of target compounds were performed using the enhanced product ion modus (EPI) of the linear ion trap. The novel LC-QTrap-MS platform offers the best sensitivity and specificity for characterization and quantitative determination of the four alkaloids in C. decumbens (Thunb.) Pers. and fulfils the quality criteria for routine laboratory application.

  11. MS/MS studies for the selective detection of isomeric biogenic VOCs using a Townsend Discharge Triple Quadrupole Tandem MS and a PTR-Linear Ion Trap MS

    Directory of Open Access Journals (Sweden)

    M. Müller

    2009-08-01

    Full Text Available We performed MS/MS investigations of biogenic volatile organic compounds (BVOC using a triple quadrupole tandem mass spectrometer (QqQ-MS equipped with a Townsend Discharge ion source and a Proton Transfer Reaction Linear Ion Trap (PTR-LIT mass spectrometer. Both instruments use H2O chemical ionization to produce protonated molecular ions. Here we report a study of the application of these instruments to determine methyl vinyl ketone (MVK and methacrolein (MACR and a series of monoterpenes (α-pinene, β-pinene, 3-carene, limonene, myrcene, ocimene and sesquiterpenes (humulene and farnesene. Both instruments achieved sub-ppb detection limits in the single MS mode and in the MS/MS mode for differentiating MVK and MACR. Collision induced dissociation (CID of protonated monoterpenes and sesquiterpenes was studied under the high-energy, single-to-few collision conditions of the QqQ-MS instrument and under the low-energy, multiple collision conditions of the PTR-LIT. Differences and similarities in the breakdown curves obtained are discussed. In addition, we performed MS4 of protonated limonene to illustrate the analytical power of the PTR-LIT. In spite of the progress we have made, the selective on-line mass-spectrometric detection of individual monoterpenes or sesquiterpenes in complex mixtures currently does not yet seem to be possible.

  12. Confirmation of pinnatoxins and spirolides in shellfish and passive samplers from Catalonia (Spain) by liquid chromatography coupled with triple quadrupole and high-resolution hybrid tandem mass spectrometry.

    Science.gov (United States)

    García-Altares, María; Casanova, Alexis; Bane, Vaishali; Diogène, Jorge; Furey, Ambrose; de la Iglesia, Pablo

    2014-06-01

    Cyclic imines are lipophilic marine toxins that bioaccumulate in seafood. Their structure comprises a cyclic-imino moiety, responsible for acute neurotoxicity in mice. Cyclic imines have not been linked yet to human poisonings and are not regulated in Europe, although the European Food Safety Authority requires more data to perform a conclusive risk assessment for consumers. This work presents the first detection of pinnatoxin G (PnTX-G) in Spain and 13-desmethyl spirolide C (SPX-1) in shellfish from Catalonia (Spain, NW Mediterranean Sea). Cyclic imines were found at low concentrations (2 to 60 µg/kg) in 13 samples of mussels and oysters (22 samples analyzed). Pinnatoxin G has been also detected in 17 seawater samples (out of 34) using solid phase adsorption toxin tracking devices (0.3 to 0.9 µg/kg-resin). Pinnatoxin G and SPX-1 were confirmed with both low and high resolution (<2 ppm) mass spectrometry by comparison of the response with that from reference standards. For other analogs without reference standards, we applied a strategy combining low resolution MS with a triple quadrupole mass analyzer for a fast and reliable screening, and high resolution MS LTQ Orbitrap® for unambiguous confirmation. The advantages and limitations of using high resolution MS without reference standards were discussed.

  13. Comparison between triple quadrupole, time of flight and hybrid quadrupole time of flight analysers coupled to liquid chromatography for the detection of anabolic steroids in doping control analysis.

    Science.gov (United States)

    Pozo, Oscar J; Van Eenoo, Peter; Deventer, Koen; Elbardissy, Hisham; Grimalt, Susana; Sancho, Juan V; Hernandez, Felix; Ventura, Rosa; Delbeke, Frans T

    2011-01-17

    Triple quadrupole (QqQ), time of flight (TOF) and quadrupole-time of flight (QTOF) analysers have been compared for the detection of anabolic steroids in human urine. Ten anabolic steroids were selected as model compounds based on their ionization and the presence of endogenous interferences. Both qualitative and quantitative analyses were evaluated. QqQ allowed for the detection of all analytes at the minimum required performance limit (MRPL) established by the World Anti-Doping Agency (between 2 and 10 ng mL(-1) in urine). TOF and QTOF approaches were not sensitive enough to detect some of the analytes (3'-hydroxy-stanozolol or the metabolites of boldenone and formebolone) at the established MRPL. Although a suitable accuracy was obtained, the precision was unsatisfactory (RSD typically higher than 20%) for quantitative purposes irrespective of the analyser used. The methods were applied to 30 real samples declared positives either for the misuse of boldenone, stanozolol and/or methandienone. Most of the compounds were detected by every technique, however QqQ was necessary for the detection of some metabolites in a few samples. Finally, the possibility to detect non-target steroids has been explored by the use of TOF and QTOF. The use of this approach revealed that the presence of boldenone and its metabolite in one sample was due to the intake of androsta-1,4,6-triene-3,17-dione. Additionally, the intake of methandienone was confirmed by the post-target detection of a long-term metabolite.

  14. Toxin screening in phytoplankton: detection and quantitation using MALDI triple quadrupole mass spectrometry.

    Science.gov (United States)

    Sleno, Lekha; Volmer, Dietrich A

    2005-03-01

    The investigation of a MALDI triple quadrupole instrument for the analysis of spirolide toxins in phytoplankton samples is described in this study. A high-frequency (kHz) laser was employed for MALDI, generating a semicontinuous ion beam, thus taking advantage of the high duty cycle obtained in sensitive triple quadrupole MRM experiments. Initially, several experimental parameters such as type of organic matrix and concentration, solvent composition, and matrix-to-analyte ratio were optimized, and their impact on sensitivity and precision of the obtained ion currents for a reference spirolide, 13-desmethyl-C, was studied. In all quantitative experiments, excellent linearities in the concentration range between 0.01 and 1.75 microg/mL were obtained, with R2 values of 0.99 or higher. The average precision of the quantitative MALDI measurements was 7.4+/-2.4% RSD. No systematic errors were apparent with this method as shown by a direct comparison to an electrospray LC/MS/MS method. Most importantly, the MALDI technique was very fast; each sample spot was analyzed in less than 5 s as compared to several minutes with the electrospray assay. To demonstrate the potential of the MALDI triple quadrupole method, its application to quantitative analysis in several different phytoplankton samples was investigated, including crude extracts and samples from mass-triggered fractionation experiments. 13-Desmethyl spirolide C was successfully quantified in these complex samples at concentration levels from 0.05 to 90.4 microg/mL (prior to dilution to have samples fall within the dynamic range of the method) without extensive sample preparation steps. The versatility of the MALDI triple quadrupole method was also exhibited for the identification of unknown spirolide analogues. Through the use of dedicated linked scan functions such as precursor ion and neutral loss scans, several spirolide compounds were tentatively identified directly from the crude extract, without the usual time

  15. Characterization of xylazine metabolism in rat liver microsomes using liquid chromatography-hybrid triple quadrupole-linear ion trap-mass spectrometry.

    Science.gov (United States)

    Lavoie, David St-Germain; Pailleux, Floriane; Vachon, Pascal; Beaudry, Francis

    2013-07-01

    Xylazine is an α2 -adrenoceptor agonist and it is widely used in veterinary anesthesia in combination with ketamine. There is limited information on the metabolism of xylazine. A quantitative method for the determination of xylazine by HPLC-ESI/MS/MS was developed. The method consisted of a protein precipitation extraction followed by analysis using liquid chromatography electrospray tandem mass spectrometry. The chromatographic separation was achieved using a Thermo Betasil Phenyl 100 × 2 mm column combined with an isocratic mobile phase composed of acetonitrile, methanol, water and formic acid (60:20:20:0.4) at a flow rate of 300 μL/min. The mass spectrometer was operating in selected reaction monitoring mode and the analytical range was set at 0.05-50 μm. The precision (%CV) and accuracy (%NOM) observed were 2.3-7.2 and 88.2-96.4%. In vitro metabolism studies were performed in rat liver microsomes and results showed moderate cytochrome P450 affinity (Km = 10.1 μm) and a low metabolic stability of xylazine with a half-life of 4.1 min in rat liver microsomes. Five phase 1 metabolites were observed. The main metabolite observed was an oxidation of the thiazine moiety at m/z 235 and, to a lesser extent, we observed the formation of N-(2,6-dimethylphenyl)thiourea at m/z 181 and three distinctive hydroxylated metabolites at m/z 237. Further experiments with ketamine and ketoconazole strongly supported that the metabolism of xylazine to its main metabolite is mediated by CYP3A in rat liver microsomes.

  16. Multiple Reaction Monitoring for Direct Quantitation of Intact Proteins Using a Triple Quadrupole Mass Spectrometer.

    Science.gov (United States)

    Wang, Evelyn H; Combe, Peter C; Schug, Kevin A

    2016-05-01

    Methods that can efficiently and effectively quantify proteins are needed to support increasing demand in many bioanalytical fields. Triple quadrupole mass spectrometry (QQQ-MS) is sensitive and specific, and it is routinely used to quantify small molecules. However, low resolution fragmentation-dependent MS detection can pose inherent difficulties for intact proteins. In this research, we investigated variables that affect protein and fragment ion signals to enable protein quantitation using QQQ-MS. Collision induced dissociation gas pressure and collision energy were found to be the most crucial variables for optimization. Multiple reaction monitoring (MRM) transitions for seven standard proteins, including lysozyme, ubiquitin, cytochrome c from both equine and bovine, lactalbumin, myoglobin, and prostate-specific antigen (PSA) were determined. Assuming the eventual goal of applying such methodology is to analyze protein in biological fluids, a liquid chromatography method was developed. Calibration curves of six standard proteins (excluding PSA) were obtained to show the feasibility of intact protein quantification using QQQ-MS. Linearity (2-3 orders), limits of detection (0.5-50 μg/mL), accuracy (protein. Sensitivities for different proteins varied considerably. Biological fluids, including human urine, equine plasma, and bovine plasma were used to demonstrate the specificity of the approach. The purpose of this model study was to identify, study, and demonstrate the advantages and challenges for QQQ-MS-based intact protein quantitation, a largely underutilized approach to date.

  17. Multiple Reaction Monitoring for Direct Quantitation of Intact Proteins Using a Triple Quadrupole Mass Spectrometer

    Science.gov (United States)

    Wang, Evelyn H.; Combe, Peter C.; Schug, Kevin A.

    2016-05-01

    Methods that can efficiently and effectively quantify proteins are needed to support increasing demand in many bioanalytical fields. Triple quadrupole mass spectrometry (QQQ-MS) is sensitive and specific, and it is routinely used to quantify small molecules. However, low resolution fragmentation-dependent MS detection can pose inherent difficulties for intact proteins. In this research, we investigated variables that affect protein and fragment ion signals to enable protein quantitation using QQQ-MS. Collision induced dissociation gas pressure and collision energy were found to be the most crucial variables for optimization. Multiple reaction monitoring (MRM) transitions for seven standard proteins, including lysozyme, ubiquitin, cytochrome c from both equine and bovine, lactalbumin, myoglobin, and prostate-specific antigen (PSA) were determined. Assuming the eventual goal of applying such methodology is to analyze protein in biological fluids, a liquid chromatography method was developed. Calibration curves of six standard proteins (excluding PSA) were obtained to show the feasibility of intact protein quantification using QQQ-MS. Linearity (2-3 orders), limits of detection (0.5-50 μg/mL), accuracy (protein. Sensitivities for different proteins varied considerably. Biological fluids, including human urine, equine plasma, and bovine plasma were used to demonstrate the specificity of the approach. The purpose of this model study was to identify, study, and demonstrate the advantages and challenges for QQQ-MS-based intact protein quantitation, a largely underutilized approach to date.

  18. Simultaneous determination of 24 constituents in Cortex Lycii using high-performance liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Zhang, Jing-Xian; Guan, Shu-Hong; Yang, Min; Feng, Rui-Hong; Wang, Yang; Zhang, Yi-Bei; Chen, Xin; Chen, Xiao-Hui; Bi, Kai-Shun; Guo, De-An

    2013-04-15

    A fast high-performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) tandem mass spectrometry method was developed to determine 24 components including 11 phenolic compounds, 9 phenolic amides, and 4 cyclic peptides in Cortex Lycii. The analytes were quantified by a triple quadrupole instrument in multiple reaction monitoring (MRM) mode. The fragmentation patterns of phenolic amides and cyclic peptides using ESI and collision-induced dissociation (CID) techniques are reported. This assay method was validated with respect to linearity (r(2)>0.9920), precision, repeatability, and accuracy (recovery rate between 93.0 and 105.9% with RSDPrinciple component analysis (PCA) was used to discriminate samples from different geographical regions of China, and cyclic peptides were considered to be the chemical markers responsible for the classification. The systematic and integrated assessment of Cortex Lycii provides sufficient evidence for the establishment of the quality standard.

  19. Correlation between y-type ions observed in ion trap and triple quadrupole mass spectrometers.

    Science.gov (United States)

    Sherwood, Carly A; Eastham, Ashley; Lee, Lik Wee; Risler, Jenni; Vitek, Olga; Martin, Daniel B

    2009-09-01

    Multiple reaction monitoring mass spectrometry (MRM-MS) is a technique for high-sensitivity targeted analysis. In proteomics, MRM-MS can be used to monitor and quantify a peptide based on the production of expected fragment peaks from the selected peptide precursor ion. The choice of which fragment ions to monitor in order to achieve maximum sensitivity in MRM-MS can potentially be guided by existing MS/MS spectra. However, because the majority of discovery experiments are performed on ion trap platforms, there is concern in the field regarding the generalizability of these spectra to MRM-MS on a triple quadrupole instrument. In light of this concern, many operators perform an optimization step to determine the most intense fragments for a target peptide on a triple quadrupole mass spectrometer. We have addressed this issue by targeting, on a triple quadrupole, the top six y-ion peaks from ion trap-derived consensus library spectra for 258 doubly charged peptides from three different sample sets and quantifying the observed elution curves. This analysis revealed a strong correlation between the y-ion peak rank order and relative intensity across platforms. This suggests that y-type ions obtained from ion trap-based library spectra are well-suited for generating MRM-MS assays for triple quadrupoles and that optimization is not required for each target peptide.

  20. Analysis of butadiene urinary metabolites by liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    McDonald, Jacob D; Bechtold, William E; Krone, Jennifer R; Blackwell, Walter B; Kracko, Dean A; Henderson, Rogene F

    2004-04-01

    1,3-Butadiene (BD) is a monomer produced in petrochemical production facilities and from several combustion sources. The United States Environmental Protection Agency has defined BD as a probable human carcinogen. Methods for assessing exposure and internal dose are therefore of critical interest, and one technique is the measurement of urinary metabolites. Here we describe methods for measuring two urinary metabolites, N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (referred to as MI) and an isomeric mixture of the regio- and stereoisomers (R)/(S)-N-acetyl-S-(1-(hydroxymethyl)-2-propen-yl)-L-cysteine and (R)/(S)-N-acetyl-S-(2-hydroxy-3-butenyl)-L-cysteine (referred to as MII). The method is based on isolation of the metabolites by solid-phase extraction and measurement using liquid chromatography and triple quadrupole mass spectrometry (LC-MS(3)). The LC-MS(3) allowed good selectivity with minimal sample preparation. Assay accuracy was within 10% or better, with substantial improvement in accuracy accompanying the commercial availability of deuterated internal standards for both compounds. Assay precision and linearity passed rigorous validation criteria, and precision-based limits of quantitation values were 12 and 1 ng/mL for MI and MII, respectively. Data are shown from analysis of human urine from occupationally exposed individuals and rat urine from BD exposures conducted to investigate rodent metabolic profiles. Both of these data sets clearly show that this assay can discern previously described relationships between BD exposure and the production of MI/MII.

  1. Simultaneous determination of 23 flavor additives in tobacco products using gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Zhang, Yi; Wang, Xiujuan; Li, Li; Li, Weiqing; Zhang, Feng; Du, Tianxin; Chu, Xiaogang

    2013-09-06

    A method based on gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ MS/MS) was developed for the determination of 23 widely used flavor additives in tobacco products in this paper. The MS/MS fragmentation pathway of the cinnamic esters additives was illustrated. The new analytical method was defined based on two main axes, ultrasonic solvent extraction procedure with dichloromethane and analyte detection performed by GC-QqQ MS/MS in electron impact mode. The excellent selectivity and sensitivity achieved in multiple reactions monitoring (MRM) mode allowed satisfactory confirmation and quantitation for the tobacco flavor additives. The linear range of the 23 flavor additives is 0.2-500.0μg/L with good correlation coefficients (r(2)>0.9963). The limits of detection (LODs) and limits of quantitation (LOQs) of these compounds were in the range 0.1-2.0μg/L and 0.4-6.0μg/kg, respectively. The average recoveries at three spiked levels (LOQ, 2LOQ, 4LOQ) were all in the range 62.1-93.8% with RSDs (n=6) lower than 7.8%. The method of GC-QqQ MS/MS developed in this study was initially applied to the research of flavor additives in 12 retail cigarette samples and proved to be accurate, sensitive, convenient and practical. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Quantification of steroidal alkaloids in Buxus papillosa using electrospray ionization liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Musharraf, Syed Ghulam; Goher, Madiha; Zareena, Bibi

    2015-08-01

    Buxus papillosa is one of the most extensively studied species of the genus Buxus known to possess steroidal alkaloids which can be used for assessing the various pharmacological activities of this plant. This paper describes the liquid chromatography-electrospray ionization triple quadrupole mass spectrometry (LC-ESI-QQQ-MS) method for the quantification of six steroidal alkaloids as chemical markers in the extracts of leaves, roots and stems of B. papillosa. Quantitative MS/MS analysis was carried out by optimization of the most sensitive transition for each analyte. This has yielded detection and quantification limits of 0.486-8.08 ng/mL and 1.473-24.268 ng/mL, respectively for all analytes. Linearity of response was also achieved and the regression coefficient found to be >0.99 for all analyzed compounds. The newly developed MRM (Multiple Reaction Monitoring) method showed excellent sensitivity for the quantification of steroidal alkaloids within 15 min run time. This paper describes the application of LC-QQQ-MS technique for steroidal alkaloids analysis in plant samples.

  3. [Determination of 99 pesticide residues in Paeoniae Radix Alba by gas chromatography-triple quadrupole tandem mass spectrometry].

    Science.gov (United States)

    Liu, Xiaoqin; Tong, Ling; Meng, Wenting; Sun, Guoxiang

    2015-08-01

    A method was established for the simultaneous determination of 99 pesticide residues with combination of solid-phase extraction technique ( SPE) and gas chromatography-triple quadrupole tandem mass spectrometry (GC-QqQ-MS). The sample was extracted with ethyl acetate, and cleaned-up by an amino SPE column. The extract was determined by GC-MS/MS in multi-reaction monitoring (MRM) mode, and matrix-matched internal standard method was applied to quantify the pesticides. The results of all the 99 pesticides showed good linearity in the range of 0.001-0.25 mg/L, with correlation coefficients (r2) > 0.99. The limits of quantification (LOQs) were between 0.001-0.050 mg/kg. The recoveries were between 66.7% and 128.0% with RSD values typically lower than 18.3% at three spiked levels of 0.05, 0.10 and 0.20 mg/kg. This method has been applied to determine thirteen batches of commercially available samples, chlorpyriphos-ethyl and p,p'-DDE were detected in four batches of Paeoniae Radix Alba. The method is highly accurate, reliable and sensitive for monitoring the 99 pesticide residues in Paeoniae Radix Alba.

  4. Multidrug analysis of pharmaceutical and urine matrices by on-line coupled capillary electrophoresis and triple quadrupole mass spectrometry.

    Science.gov (United States)

    Maráková, Katarína; Piešt'anský, Juraj; Veizerová, Lucia; Galba, Jaroslav; Dokupilová, Svetlana; Havránek, Emil; Mikuš, Peter

    2013-06-01

    The present work illustrates potentialities of CE hyphenated with MS/MS for the simultaneous determination and identification of a mixture of simultaneously acting drugs in pharmaceutical and biological matrices. Here, the hyphenation was provided by ESI interface, while the MS/MS technique was based on the triple quadrupole configuration. Three drugs, namely pheniramine, phenylephrine, and paracetamol were determined and identified with high reliability due to their characterization in three different dimensions, i.e. electrophoresis and MS/MS, that prevented practically any interference. Appropriately selected transitions of the analytes (parent ion-quantifier product ion-qualifier product ion) provided their selective determination at maximum S/N. The proposed CE-MS/MS method was validated (LOD/LOQ, linearity, precision, recovery, accuracy) and applied for (i) the multidrug composition pharmaceuticals, namely Theraflu®, and (ii) human urine taken after per-oral administration of the same pharmaceutical preparation. The method was applied also for the investigation of potential weak associates of the drugs and monitoring of predicted (bio)degradation products of the drugs. Successful validation and application of the proposed method suggest its routine use in highly effective and reliable advanced drug control and biomedical research.

  5. Quantitative analysis of antiretroviral drugs in lysates of peripheral blood mononuclear cells using MALDI-triple quadrupole mass spectrometry.

    NARCIS (Netherlands)

    Kampen, JJ van; Burgers, P.C.; Gruters, R.A.; Osterhaus, A.D.; Groot, R. de; Luider, T.M.; Volmer, D.A.

    2008-01-01

    We report here on the use of a prototype matrix-assisted laser desorption/ionization (MALDI)-triple quadrupole mass spectrometer for quantitative analysis of six antiretroviral drugs in lysates of peripheral blood mononuclear cells (PBMC). Of the five investigated MALDI matrixes, 2,5-dihydroxybenzoi

  6. [Determination of Total Sulfur Dioxide in Chinese Herbal Medicines via Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry].

    Science.gov (United States)

    Wang, Xiao-wei; Liu, Jing-fu; Guan, Hong; Wang, Xiao-yan; Shag, Bing; Zhang, Jing; Liu, Li-ping; Zhang, Ni-na

    2016-02-01

    As an important treatment method, sulfur fumigation plays an essential role in the production and preservation of traditional Chinese herbal medicines. Although there is strict regulation on the use of sulfur dioxide, the abuse of sulfur dioxide still occurred from time to time. And the public faces a high risk of exposure. Because of the poor precision and tedious preparation procedures of traditional recommended titration, the accurate and convenient determination of sulfur dioxide in Chinese herbal medicines is still a critical analytical task for medicines safety and the public health. In this study, an accurate, high-throughput, and convenient method for the absolute determination of SO₂ in Chinese herbal medicines based on triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) technique is developed. The study compared the quantitative ability for sulfur when the ICP-MS operated under traditional single quadrupole (QMS) mode and novel triple quadrupole (MS/MS) mode with three Reaction/Collision cell condition (no gas, helium, and oxygen). The result indicated that when the concentration of sulfate ranging from 0.5 to 100 mg · L⁻¹, isotopic ³⁴S can be selected as quantitative ion either the ICP-MS operated under the QMS mode or MS/MS mode. The use of helium in the Reaction/Collision cell decreased the single intensity of background ions. Better than QMS mode, the MS/MS mode can effectively reduced background interference. But there are no significant differences about the linear range and limit of detection. However, when the ICP-MS operated under MS/MS mode and oxygen was used as reaction gas in the Reaction/Collision cell, the ICP-MS/MS provided an interference-free performance, the linear range and limit of detection improved significantly. Either ³²S or ³⁴S exhibits an excellent linearity (r > 0.999) over the concentration range of 0.02-100 mg · L⁻¹, with a limit of detection of 5.48 and 9.76 µg · L⁻¹ for

  7. [Simultaneous determination of ethyl carbamate and chloropropanols in flavorings by gas chromatography-triple quadrupole tandem mass spectrometry].

    Science.gov (United States)

    Xu, Xiaomin; He, Huali; Ruan, Yudi; Huang, Baifen; Zhang, Jingshun; Cai, Zengxuan; Ren, Yiping

    2013-11-01

    A simultaneous determination method for ethyl carbamate (EC) and chloropropanols (3-monochloropropane-1, 2-diol (3-MCPD) and 2-monochloropropane-1, 3-diol (2-MCPD)) in flavorings was developed by gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS). After spiked with internal standard, the sample was extracted by matrix solid-phase dispersion extraction technique with an Extrelut NT column. Hexane was used to wash the fat soluble matrix interferences and then an ethyl acetate-ethyl ether (20: 80, v/v) mixture was added to elute the analytes. The concentrated extract was detected by GC-MS/MS in multiple reaction monitoring (MRM) mode. The limits of detection (LODs) were 2, 5 and 5 microg/kg for EC, 3-MCPD and 2-MCPD, respectively. The linear ranges were 5 - 1 000 microg/kg (r = 0.9997), 10-1000 microg/kg (r = 0.999 1) and 10-1000 microg/kg (r = 0.999 5) for EC, 3-MCPD and 2-MCPD, respectively. In soy sauce, yellow rice wine, salami sauce and flavoring of instant noodle matrices, the recoveries (RSDs, n = 7) in MRM mode at the levels of 20, 100 and 400 microg/kg were 87.7%-104% (4.3%-10.7%), 90.1%-109% (2.6%-10.2%), and 90.9%-103% (3.0%-9.5%), respectively. EC, 3-MCPD and 2-MCPD were found in some real samples of the soy sauce, wine and flavoring of instant noodle. EC or 3-MCPD was found in some of the salami samples. The method is accurate, fast and suitable for the simultaneous determination of EC, 3-MCPD and 2-MCPD in flavorings.

  8. Determination of albendazole and metabolites in silkworm Bombyx mori hemolymph by ultrafast liquid chromatography tandem triple quadrupole mass spectrometry.

    Science.gov (United States)

    Li, Li; Xing, Dong-Xu; Li, Qing-Rong; Xiao, Yang; Ye, Ming-Qiang; Yang, Qiong

    2014-01-01

    Albendazole is a broad-spectrum parasiticide with high effectiveness and low host toxicity. No method is currently available for measuring albendazole and its metabolites in silkworm hemolymph. This study describes a rapid, selective, sensitive, synchronous and reliable detection method for albendazole and its metabolites in silkworm hemolymph using ultrafast liquid chromatography tandem triple quadrupole mass spectrometry (UFLC-MS/MS). The method is liquid-liquid extraction followed by UFLC separation and quantification in an MS/MS system with positive electrospray ionization in multiple reaction monitoring mode. Precursor-to-product ion transitions were monitored at 266.100 to 234.100 for albendazole (ABZ), 282.200 to 208.100 for albendazole sulfoxide (ABZSO), 298.200 to 159.100 for albendazole sulfone (ABZSO2) and 240.200 to 133.100 for albendazole amino sulfone (ABZSO2-NH2). Calibration curves had good linearities with R2 of 0.9905-0.9972. Limits of quantitation (LOQs) were 1.32 ng/mL for ABZ, 16.67 ng/mL for ABZSO, 0.76 ng/mL for ABZSO2 and 5.94 ng/mL for ABZSO2-NH2. Recoveries were 93.12%-103.83% for ABZ, 66.51%-108.51% for ABZSO, 96.85%-105.6% for ABZSO2 and 96.46%-106.14% for ABZSO2-NH2, (RSDs albendazole and its metabolites in silkworm hemolymph in a pharmacokinetic study. The results of single-dose treatment suggested that the concentrations of ABZ, ABZSO and ABZSO2 increased and then fell, while ABZSO2-NH2 level was low without obvious change. Different trends were observed for multi-dose treatment, with concentrations of ABZSO and ABZSO2 rising over time.

  9. Determination of pesticide residues in animal origin baby foods by gas chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Amendola, Graziella; Pelosi, Patrizia; Attard Barbini, Danilo

    2015-01-01

    A simple, fast and multiresidue method for the determination of pesticide residues in baby foods of animal origin has been developed in order to check the compliance with the Maximum Residue Levels (MRLs) set at a general value of 0.01 mg/kg by Commission Directive 2006/125/EC for infant foods. The main classes of organochlorine, organophosphorus and pyrethroid compounds have been considered, which are mainly fat soluble pesticides. The analytical procedure consists in the extraction of baby food samples by acetonitrile (ACN) followed by a clean up using C18 solid-phase extraction column eluted with ACN. The compounds were determined by gas chromatography-triple quadrupole mass spectrometry equipped with a Programmed Temperature Vaporizer (PTV) injection and a backflush system. In order to compensate for matrix effects PTV and matrix matched standard calibrations have been used. The method has been fully validated for 57 pesticides according to the Document SANCO/12571/2013. Accuracy and precision (repeatability) have been studied by recoveries at two spiking levels, the Limit of Quantitation (LOQ) (0.003-0.008 mg/kg) and 10 time greater (0.03-0.08 mg/kg), and the results were in the acceptable range of 70-120% with Relative Standards Deviations (RSD) ≤20%. Selectivity, linearity, LOQ and uncertainty of measurement were also determined for all the compounds. The method has been also applied for the analysis of 18 baby food animal origin samples, bought form the local market in Rome (Italy), and no pesticide in the scope of the method has been found above the MRL or the LOQ.

  10. [Determination of 16 phthalate acid ester residues in health wine by gas chromatography-triple quadrupole mass spectrometry].

    Science.gov (United States)

    Lu, Li; Gong, Xu; Feng, Youlong

    2014-11-01

    A method for the analysis of sixteen phthalate acid ester (PAE) residues in health wine was developed using gas chromatography-triple quadrupole mass spectrometry (GC-QQQ- MS). The health wine samples were extracted with n-hexane by liquid-liquid extraction method before analysis. The samples were detected by GC-QQQ-MS with electron impact source (EI) in selected ion monitoring (SIM) mode after extraction. The separation was performed on an HP-5MS capillary column (30 m x 0.25 mm x 0.25 μm) with temperature programming. The retention time and the fragment ion abundance ratio were used to judge the qualitative results, and the quantitation was performed with standard curve method of the characteristic ion chrom- atographic peak area-concentration. Eighty-one batches of health wine samples were detected using the method. The results showed that the method had good linear relationships with correlation coefficients (r2) not less than 0.995 9. The recoveries of fifteen PAEs ranged from 88.6% to 107. 3% except dimethyl phthalate (DMP) which was 52.3%-58.7% in all the three spiked levels with the relative standard deviations of 0.1%-6.8% (RSD, n = 6). The limits of detection were between 0.002 mg/L to 0.061 mg/L. The limits of quantification were between 0.005 mg/L and 0.202 mg/L. The method is accurate, sensitive, proprietary and suitable for the simultaneous determination of the sixteen phthalate acid esters in health wine.

  11. Simultaneous determination of iridoid glycosides, phenethylalcohol glycosides and furfural derivatives in Rehmanniae Radix by high performance liquid chromatography coupled with triple-quadrupole mass spectrometry

    DEFF Research Database (Denmark)

    Xu, Jun; Wu, Jie; Zhu, Ling-Ying

    2012-01-01

    In this study, a sensitive and selective method for simultaneously quantifying eight major components (four iridoid glycosides, three phenethylalcohol glycosides and one furfural derivative) of Rehmanniae Radix by high performance liquid chromatography coupled with triple-quadrupole mass...

  12. The role of GC-MS/MS with triple quadrupole in pesticide residue analysis in food and the environment

    OpenAIRE

    Hernández Hernández, Félix; Cervera Vidal, María Inés; Portolés Nicolau, Tania; Beltrán Arandes, Joaquim; Pitarch Arquimbau, María Elena

    2013-01-01

    Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole (QqQ) analyzer has in the last few years become a powerful technique for the determination of pesticide residues due to its robustness, and excellent sensitivity and selectivity. This review gives an overview of currently published applications of GC-MS/MS with a QqQ analyzer for pesticide residue analysis of different food and environmental sample matrices. This technique allows the reliable quantific...

  13. Large-molecule quantification: sensitivity and selectivity head-to-head comparison of triple quadrupole with Q-TOF.

    Science.gov (United States)

    Morin, Louis-Philippe; Mess, Jean-Nicholas; Garofolo, Fabio

    2013-05-01

    Bioanalysts are continuously looking for innovative ideas or instruments to increase the sensitivity and selectivity of their assays. Research for better mass spectrometers is becoming crucial with the emerging trend of large-molecule quantification. This study lists the different advantages of high-resolution MS (HRMS) over standard triple quadrupole instruments and proposes basic guidelines on how to use HRMS for large-molecule quantification in a regulated environment. A direct comparison between HRMS and triple quadrupole instruments for the quantification of six different model peptides (desmopressin, calcitonin, enfuvirtide, exenatide, glucagon and somatostatin) was completed. The HRMS instrument, when used specifically for targeted quantification ('quant/quant'), showed equivalent or better sensitivity for all compounds tested. This paper demonstrates that the use of a HRMS instrument in a regulated environment is a viable technique for quantification of large molecules. The latter was able to allow flexibility and selectivity to adapt the specificity of each assay with sensitivity comparable to the triple quadrupole instrument.

  14. Gas chromatography–triple quadrupole mass spectrometry for the determination of atmospheric polychlorinated naphthalenes

    Energy Technology Data Exchange (ETDEWEB)

    Li, Fang [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Jin, Jing [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); Sun, Xiaoli [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); University of Chinese Academy of Sciences, Beijing 100049 (China); Wang, Xueli; Li, Yun; Shah, Syed Mazhar [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China); Chen, Jiping, E-mail: chenjp@dicp.ac.cn [Key Laboratory of Separation Science for Analytical Chemistry, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, No. 457 Zhongshan Road, Dalian 116023 (China)

    2014-09-15

    Highlights: • Atmospheric PCNs were detected by isotope-dilution GC–MS/MS. • The pollution levels of PCNs covering from mono- to octa-CNs were investigated comprehensively in air samples. • The dioxin-like toxicity and human exposure levels of PCNs in air samples were estimated. - Abstract: Atmospheric polychlorinated naphthalenes (PCNs) ranging from mono-CNs to octa-CNs were detected using isotope-dilution gas chromatography coupled with triple quadrupole mass spectrometry (GC–MS/MS). The developed instrumental method was successfully applied to the determination of PCNs in technical products. It was observed that there were significant differences in concentrations, homologue profiles, chlorinated contents and total toxic equivalents (∑TEQs) of PCNs for four Halowax products. Subsequently, the validation of the analytical method was evaluated for the determination of PCNs in air samples in terms of method detection limit (MDL), recovery and matrix effect. The results demonstrated that this method could provide satisfactory sensitivity and adequate selectivity with lower cost. It was conducted to comprehensively evaluate the levels, composition patterns, ∑TEQs, and daily intake exposure of PCNs in indoor and outdoor air samples. Concentrations and ∑TEQs of PCNs in air samples ranged 47.7–832.7 pg m{sup −3} and 1.31–5.99 fg m{sup −3}, respectively, and the predominant homologues were di- and tri-CNs in the gas phase. The results indicated that this analytical method was useful for the accurate and specific evaluation of dioxin-like toxicity and human exposure levels of PCNs in the atmosphere.

  15. Adduct formation in liquid chromatography-triple quadrupole mass spectrometric measurement of bryostatin 1.

    Science.gov (United States)

    Nelson, Thomas J; Sen, Abhik; Alkon, Daniel L; Sun, Miao-Kun

    2014-01-01

    Bryostatin 1, a potential anti-Alzheimer drug, is effective at subnanomolar concentrations. Measurement is complicated by the formation of low m/z degradation products and the formation of adducts with various cations, which make accurate quantitation difficult. Adduct formation caused the sample matrix or mobile phase to partition bryostatin 1 into products of different mass. Degradation of the 927 [M+Na](+) ion to a 869m/z product was strongly influenced by ionization conditions. We validated a bryostatin 1 assay in biological tissues using capillary column HPLC with nanospray ionization (NSI) in a triple-quadrupole mass spectrometer in selected reaction monitoring (SRM) mode. Adduct formation was controlled by adding 1mM acetic acid and 0.1mM sodium acetate to the HPLC buffer, maximizing the formation of the [M+Na](+) ion. Efficient removal of contaminating cholesterol from the sample during solvent extraction was also critical. The increased sensitivity provided by NSI and capillary-bore columns and the elimination of signal partitioning due to adduct formation and degradation in the ionization source enabled a detection limit of 1×10(-18)mol of bryostatin 1 and a LLOQ of 3×10(-18)mol from 1μl of sample. Bryostatin 1 at low pmol/l concentrations enabled measurement in brain and other tissues without the use of radioactive labels. Despite bryostatin 1's high molecular weight, considerable brain access was observed, with peak brain concentrations exceeding 8% of the peak blood plasma concentrations. Bryostatin 1 readily crosses the blood-brain barrier, reaching peak concentrations of 0.2nM, and specifically activates and translocates brain PKCɛ. Copyright © 2013 Elsevier B.V. All rights reserved.

  16. Interfacing an ion mobility spectrometry based explosive trace detector to a triple quadrupole mass spectrometer.

    Science.gov (United States)

    Kozole, Joseph; Stairs, Jason R; Cho, Inho; Harper, Jason D; Lukow, Stefan R; Lareau, Richard T; DeBono, Reno; Kuja, Frank

    2011-11-15

    Hardware from a commercial-off-the-shelf (COTS) ion mobility spectrometry (IMS) based explosive trace detector (ETD) has been interfaced to an AB/SCIEX API 2000 triple quadrupole mass spectrometer. To interface the COTS IMS based ETD to the API 2000, the faraday plate of the IMS instrument and the curtain plate of the mass spectrometer were removed from their respective systems and replaced by a custom faraday plate, which was fabricated with a hole for passing the ion beam to the mass spectrometer, and a custom interface flange, which was designed to attach the IMS instrument onto the mass spectrometer. Additionally, the mass spectrometer was modified to increase the electric field strength and decrease the pressure in the differentially pumped interface, causing a decrease in the effect of collisional focusing and permitting a mobility spectrum to be measured using the mass spectrometer. The utility of the COTS-ETD/API 2000 configuration for the characterization of the gas phase ion chemistry of COTS-ETD equipment was established by obtaining mass and tandem mass spectra in the continuous ion flow and selected mobility monitoring operating modes and by obtaining mass-selected ion mobility spectra for the explosive standard 2,4,6 trinitrotoluene (TNT). This analysis confirmed that the product ion for TNT is [TNT - H](-), the predominant collision-induced dissociation pathway for [TNT- H](-) is the loss of NO and NO(2), and the reduced mobility value for [TNT - H](-) is 1.54 cm(2)V(-1) s(-1). Moreover, this analysis was attained for sample amounts of 1 ng and with a resolving power of 37. The objective of the research is to advance the operational effectiveness of COTS IMS based ETD equipment by developing a platform that can facilitate the understanding of the ion chemistry intrinsic to the equipment.

  17. [Determination of aflatoxins in cereals and oils by liquid chromatography-triple quadrupole tandem mass spectrometry].

    Science.gov (United States)

    Wang, Xiupin; Li, Peiwu; Yang, Yang; Zhang, Wen; Zhang, Qi; Fan, Sufang; Yu, Li; Wang, Lin; Chen, Xiaomei; Li, Ying; Jiang, Jun

    2011-06-01

    The high performance liquid chromatography (HPLC)-triple quadrupole tandem mass spectrometry was applied for the determination of the aflatoxins: B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2), in cereals and oils. The samples were first extracted by ultrasonic method. The optimized conditions of ultrasonic extraction were as follows: temperature of 50 degrees C, extraction time of 3 min, methanol-water (containing 40 g/L NaCl) (80: 20, v/v) solution as the medium and a ratio of sample to solvent of 1 : 3 (g: mL). The extracts were then purified using an immunoaffinity column. The separation was performed on a C18 column with mobile phases of 10 mmol/L ammonium acetate and methanol in gradient elution. The sensitive detection of the four AFT compounds by electrospray ionization mass spectrometry (ESI-MS) was carried out in selected reaction monitoring (SRM) mode with aflatoxin M1 (AFM1) as the internal standard. Under the optimized conditions, the limits of detection of AFB1, AFB2, AFG1 and AFG2 were 0.002, 0.004, 0.004 and 0.012 microg/kg, respectively. The recoveries of aflatoxins in different spiked cereals and oils were in the range from 87% to 111%. The intra-day and inter-day precisions were not more than 6.7% and 5.6%, respectively. In comparison with the external standard method, this method can effectively inhibit the matrix effects, and greatly improve the accuracy.

  18. Investigation of Ion Transmission Effects on Intact Protein Quantification in a Triple Quadrupole Mass Spectrometer

    Science.gov (United States)

    Wang, Evelyn H.; Appulage, Dananjaya Kalu; McAllister, Erin A.; Schug, Kevin A.

    2017-09-01

    Recently, direct intact protein quantitation using triple quadrupole mass spectrometry (QqQ-MS) and multiple reaction monitoring (MRM) was demonstrated (J. Am. Soc. Mass Spectrom. 27, 886-896 (2016)). Even though QqQ-MS is known to provide extraordinary detection sensitivity for quantitative analysis, we found that intact proteins exhibited a less than 5% ion transmission from the first quadrupole to the third quadrupole mass analyzer in the presence of zero collision energy (ZCE). With the goal to enhance intact protein quantitation sensitivity, ion scattering effects, proton transfer effects, and mass filter resolution widths were examined for their contributions to the lost signal. Protein standards myoglobin and ubiquitin along with small molecules reserpine and vancomycin were analyzed together with various collision induced dissociation (CID) gases (N2, He, and Ar) at different gas pressures. Mass resolution settings played a significant role in reducing ion transmission signal. By narrowing the mass resolution window by 0.35 m/z on each side, roughly 75%-90% of the ion signal was lost. The multiply charged proteins experienced additional proton transfer effects, corresponding to 10-fold signal reduction. A study of increased sensitivity of the method was also conducted with various MRM summation techniques. Although the degree of enhancement was analyte-dependent, an up to 17-fold increase in sensitivity was observed for ubiquitin using a summation of multiple MRM transitions. Biological matrix, human urine, and equine plasma were spiked with proteins to demonstrate the specificity of the method. This study provides additional insight into optimizing the use and sensitivity of QqQ-MS for intact protein quantification. [Figure not available: see fulltext.

  19. [Determination of congo red in beef by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Lin, Hui; Xu, Chunxiang; Yan, Chunrong; Zhang, Zheng; Wang, Suilou

    2013-09-01

    A method was developed for the determination of congo red in beef. The analyte was identified by high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry (LC-QTOF MS) and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the congo red in the beef sample was separated on an Agilent ZORBAX Eclipse Plus C18 Rapid Resolution HD UPLC column (50 mm x 2.1 mm, 1.8 microm) HPLC , using 95% (volume percentage) methanol as the mobile phase at 0.2 mL/min. The detection was performed on an AB 4000 + triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The results showed that the linear range of congo red mass concentration was 0.03 - 1 mg/L with the correlation coefficient of 0.999 8. The method had a good precision with the RSDs lower than 5% and the recoveries ranging from 88% to 91%. The limit of detection (LOD) of congo red was 0.01 mg/L. With good reproducibility, the method is simple, fast and effective for the determination of the illegally added congo red in beef and other meat products.

  20. Determination of aromatic sulphur compounds in heavy gas oil by using (low-)flow modulated comprehensive two-dimensional gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Franchina, Flavio Antonio; Machado, Maria Elisabete; Tranchida, Peter Quinto; Zini, Cláudia Alcaraz; Caramão, Elina Bastos; Mondello, Luigi

    2015-03-27

    The present research is focused on the development of a flow-modulated comprehensive two-dimensional gas chromatography-triple quadrupole mass spectrometry (FM GC × GC-MS/MS) method for the determination of classes of aromatic organic sulphur compounds (benzothiophenes, dibenzothiophenes, and benzonaphthothiophene) in heavy gas oil (HGO). The MS/MS instrument was used to provide both full-scan and multiple-reaction-monitoring (MRM) data. Linear retention index (LRI) ranges were used to define the MRM windows for each chemical class. Calibration solutions (internal standard: 1-fluoronaphthalene) were prepared by using an HGO sample, depleted of S compounds. Calibration information was also derived for the thiophene class (along with MRM and LRI data), even though such constituents were not present in the HGO. Linearity was satisfactory over the analyzed concentration range (1-100 mg/L); intra-day precision for the lowest calibration point was always below 17%. Accuracy was also satisfactory, with a maximum percentage error of 3.5% (absolute value) found among the S classes subjected to (semi-)quantification. The highest limit of quantification was calculated to be 299 μg/L (for the C1-benzothiophene class), while the lowest was 21 μg/L (for the C4-benzothiophene class).

  1. Direct determination of fatty acid esters of 3-chloro-1, 2-propanediol in edible vegetable oils by isotope dilution - ultra high performance liquid chromatography - triple quadrupole mass spectrometry.

    Science.gov (United States)

    Li, Heli; Chen, Dawei; Miao, Hong; Zhao, Yunfeng; Shen, Jianzhong; Wu, Yongning

    2015-09-04

    A selective and sensitive ultra-high performance liquid chromatography - triple quadrupole mass spectrometry (UHPLC-MS/MS) method coupled with matrix solid phase dispersion (MSPD) extraction was developed for the direct determination of fatty acid esters of 3-chloro-1,2-propanediol (3-MCPD esters) in edible vegetable oils. The method integrated the isotope dilution technique, MSPD extraction and UHPLC - MS/MS analysis with multi-reaction monitoring mode (MRM). Matrix-matched calibration curves showed good linearity within the range of 0.01-10mgL(-1) with the correlation coefficient not less than 0.999. Limits of detection (LODs) and limit of quantification (LOQs) of the 3-MCPD esters fell into the range of 0.0001-0.02mgkg(-1) and 0.0004-0.05mgkg(-1), respectively. The recoveries for the spiked extra virgin olive oils ranged from 94.4% to 108.3%, with the relative standard deviations (RSD) ranging from 0.6% to 10.5%. The method was applied for the oil sample (T2642) of the official Food Analysis Performance Assessment Scheme (FAPAS) in 2014 and other real samples from supermarket, and the results showed that the present method was comparative to the gas chromatography-mass spectrometry (GC-MS) method based on the improved German Society for Fat Science (DGF) standard method C-III 18 (09) except for palm oil.

  2. Simultaneous determination of triptolide, tripterifordin, celastrol and nine sesquiterpene alkaloids in Tripterygium preparations using high-performance liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Luo, Heng; Wu, Xia; Huang, Hao; Chen, Shuiying; Yang, Wei; Zhang, Lei; Cui, Hongmei; Yang, Jun; Yang, Andong

    2016-01-05

    Tripterygium wilfordii tablet (TWT) and Tripterygium hypoglaucum tablet (THT), the preparations of the two Tripterygium herbs, are well known for the treatment of rheumatoid arthritis and other related inflammatory diseases clinically. In the present study, a high performance liquid chromatography (HPLC) coupled with electrospray ionization (ESI) tandem triple quadrupole mass spectrometry (QQQ/MS) method was developed for simultaneous quantification of 12 chemical components in Tripterygium preparations. The fragmentation patterns of analytes using ESI and collision-induced dissociation (CID) techniques were reported. This assay method was validated with respect to linearity (r(2)>0.9991), precision, repeatability, and accuracy (recovery rate between 97.2 and 104.2%). The proposed method was successfully applied for simultaneous quantification of the 12 compounds in Tripterygium preparations from the different manufactures. In addition, to evaluate the quality of Tripterygium preparations, partial least square discrimination analysis (PLS-DA) was performed to differentiate the contents of 12 compounds. In conclusion, the established HPLC/QQQ/MS method was proven to be useful and efficient for quality control of Tripterygium preparations.

  3. Determination of terbuthylazine and desethylterbuthylazine in human urine and hair samples by eletrospray ionization-liquid chromatography/triple quadrupole mass spectrometry.

    Science.gov (United States)

    Mercadante, Rosa; Polledri, Elisa; Fustinoni, Silvia

    2012-08-01

    Terbuthylazine (TBA) is a widely applied herbicide and an environmental contaminant. Following its use, humans, such as agricultural workers and rural residents, may be exposed. An isotope-dilution liquid chromatography coupled to electrospray-tandem mass spectrometry method for the determination of TBA, and its metabolite desethylterbuthylazine (DET) in human urine and hair was developed and validated. Under the optimised conditions, analytes were extracted from urine using a solid phase cartridge or from hair by sonication in methanol. Analytes were separated using a C18 reversed-phase chromatographic column and quantified, after positive ionization using a heated electrospray source, by a triple quadrupole mass detector in the selected reaction monitoring mode. Validation showed linear dynamic ranges up to 100 μg/L or 5.00 ng/mg hair, inter- and intra-run precisions <7%, and accuracies within 12% of spiked concentrations. Limits of quantification were 0.25 μg/L in urine and 0.01 ng/mg hair for both TBA and DET. Matrix effect evaluation showed that the isotope dilution approach allowed for the control of bias sources. TBA and DET were determined in specimens of agriculture workers exposed to TBA using the validated method. Hair samples contained TBA levels in the low nanogram per milligram range, and urine samples contained DET levels in the low microgram per liter range. Conversely, TBA levels in urine samples and DET levels in hair samples were always below the limit of quantification.

  4. [Simultaneous determination of 22 typical pharmaceuticals and personal care products in environmental water using ultra performance liquid chromatography- triple quadrupole mass spectrometry].

    Science.gov (United States)

    Wu, Chunying; Gu, Feng; Bai, Lu; Lu, Wenlong

    2015-08-01

    An analytical method for simultaneous determination of 22 typical pharmaceuticals and personal care products (PPCPs) in environmental water samples was developed by ultra performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS). An Oasis HLB solid phase extraction cartridge, methanol as washing solution, water containing 0. 1% formic acid-methanol (7:3, v/v) as the mobile phases were selected for sample pretreatment and chromatographic separation. Based on the optimized sample pretreatment procedures and separation condition, the target recoveries ranged from 73% to 125% in water with the relative standard deviations ( RSDs) from 8.8% to 17.5%, and the linear ranges were from 2 to 2 000 µg/L with correlation coefficients (R2) not less than 0.997. The method can be applied to simultaneous determination of the 22 typical PPCPs in environmental water samples because of its low detection limits and high recoveries. It can provide support and help for the related research on water environmental risk assessment and control of the micro-organic pollutants.

  5. Rapid simultaneous determination of twelve major components in Pien Tze Huang by ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Huang, Mingqing; Zhao, Haiyu; Xu, Wei; Chu, Kedan; Hong, Zhenfeng; Peng, Jun; Chen, Lidian

    2013-12-01

    An efficient method using ultra-performance LC coupled with triple quadrupole MS was developed for the rapid determination of 12 major active components in Pien Tze Huang (PZH), a well-known traditional Chinese formula. Chromatographic separation was achieved on a Waters XBridge BEH RP18 column (50 mm × 2.1 mm id, 1.7 μm) with a gradient mobile phase (A: 0.1% aqueous formic acid and B: acetonitrile with 0.1% formic acid) at a flow rate of 0.8 mL/min. The chromatographic peaks of 12 components were identified by comparing their retention time and MS data with the related reference compounds. Multiple-reaction monitoring was employed for the quantitative analysis. Ten batches of PZH were analyzed with a good linear regression relationship (r, 0.9987–0.9995), intraday precisions (RSD, 2.05–4.80%), interday precisions (RSD, 1.99–4.98%), repeatability (RSD, 2.21–4.20%), stability (RSD, 3.52–4.81%), and recovery (95.63–104.80%). By using this established method, the present study offered highly sensitive, specific, and speedy determination of 12 major components, which promoted the quality control investigation of PZH greatly.

  6. Hydrophilic interaction ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry for highly rapid and sensitive analysis of underivatized amino acids in functional foods.

    Science.gov (United States)

    Zhou, Guisheng; Pang, Hanqing; Tang, Yuping; Yao, Xin; Mo, Xuan; Zhu, Shaoqing; Guo, Sheng; Qian, Dawei; Qian, Yefei; Su, Shulan; Zhang, Li; Jin, Chun; Qin, Yong; Duan, Jin-ao

    2013-05-01

    This work presented a new analytical methodology based on hydrophilic interaction ultra-performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry in multiple-reaction monitoring mode for analysis of 24 underivatized free amino acids (FAAs) in functional foods. The proposed method was first reported and validated by assessing the matrix effects, linearity, limit of detections and limit of quantifications, precision, repeatability, stability and recovery of all target compounds, and it was used to determine the nutritional substances of FAAs in ginkgo seeds and further elucidate the nutritional value of this functional food. The result showed that ginkgo seed turned out to be a good source of FAAs with high levels of several essential FAAs and to have a good nutritional value. Furthermore, the principal component analysis was performed to classify the ginkgo seed samples on the basis of 24 FAAs. As a result, the samples could be mainly clustered into three groups, which were similar to areas classification. Overall, the presented method would be useful for the investigation of amino acids in edible plants and agricultural products.

  7. Qualitative and quantitative analysis of the chemical constituents in Mahuang-Fuzi-Xixin decoction based on high performance liquid chromatography combined with time-of-flight mass spectrometry and triple quadrupole mass spectrometers.

    Science.gov (United States)

    Sun, Qihui; Cao, Hongjie; Zhou, Yanyan; Wang, Xu; Jiang, Haiqiang; Gong, Lili; Yang, Yong; Rong, Rong

    2016-11-01

    High-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-TOF/MS) and high-performance liquid chromatography-triple quadrupole mass spectrometry (HPLC-QQQ/MS/MS) were utilized to clarify the chemical constituents of Mahuang-Fuzi-Xixin Decoction. There are 52 compounds, including alkaloids, amino acids and organic acids were identified or tentatively characterized by their characteristic high resolution mass data by HPLC-QQQ/MS/MS. In the subsequent quantitative analysis, 10 constituents, including methyl ephedrine, aconine, songrine, fuziline, neoline, talatisamine, chasmanine, benzoylmesaconine, benzoylaconine and benzoylhypaconine were simultaneously determined by HPLC-QQQ/MS/MS with multiple reaction monitoring mode. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r > 0.9992). The relative standard deviations (RSD) of inter- and intra-day precisions were chemical constituents studying, including identification and quantification of Mahuang-Fuzi-Xixin decoction. Copyright © 2016 John Wiley & Sons, Ltd.

  8. Liquid chromatography tandem mass spectrometric quantitation of sulfamethazine and its metabolites: direct analysis of swine urine by triple quadrupole and by ion trap mass spectrometry.

    Science.gov (United States)

    Bartolucci, G; Pieraccini, G; Villanelli, F; Moneti, G; Triolo, A

    2000-01-01

    This work describes a new method for the quantitation of trace amounts of sulfamethazine (SMZ) and its main metabolite, N4-acetylsulfamethazine (Ac-SMZ), in swine urine, using high-performance liquid chromatography (HPLC) tandem mass spectrometric analysis of crude urine after addition of internal standard and simple dilution with water. The aim was to determine whether residues of this sulfamidic drug, normally administered to swine in order to prevent infectious diseases, were present in urine at levels lower than those permitted by regulatory authorities before human consumption (EU Project SMT, contract number CT 96-2092). A 10 microL volume of diluted urine was injected into a very short, narrow-bore chromatographic column (Zorbax SB-C18 2.1 i. d. x30 mm length, 3.5 microm pore size). Elution of the analytes of interest was achieved in less than seven minutes using a rapid gradient (from 20 to 80% methanol in 3 minutes). Either a PE Sciex API 365 triple quadrupole (QqQ), operated in the selected reaction monitoring (SRM) mode, or a Finnigan LCQ ion trap (IT) mass spectrometer, operated in narrow-range product ion scan, was used as the final detector. Electrospray (ESI) was used as the ionization technique. A comparison of the two tandem mass spectrometers was performed by analyzing the same set of test samples, at three concentration levels, on three different days. Linearity of responses of the calibration standards, intra- and inter-assay precision of the samples, specificity and limits of detection were evaluated for both systems. Both the QqQ and the IT instrument was suitable for rapid, sensitive and specific determination of the analytes, although the overall performance of the QqQ was slightly superior in terms of linearity, precision and sensitivity.

  9. [Determination of alpha-solanine, alpha-chaconine and solanidine in plasma and urine by ultra-performance liquid chromatography-triple quadrupole mass spectrometry].

    Science.gov (United States)

    Zhang, Xiuyao; Cai, Xinxin; Zhang, Xiaoyi

    2014-06-01

    An ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS/MS) method was developed for the determination of alpha-solanine, alpha-chaconine and solanidine in plasma and urine. The sample was acidified with aqueous solution containing 2% (v/v if not specified) formic acid, and then cleaned-up by solid-phase extraction with a mixed-mode cation exchange (MCX) cartridge. The analysis of the glycoalkaloids was carried out on an Acquity UPLC BEH C18 column (50 mm x 2.1 mm, 1.7 microm) with gradient elution of acetonitrile (containing 0.1% formic acid) and H2O (containing 0.05% formic acid and 5.0 mmol/L ammonium acetate). The analytes were detected by positive electrospray ionization tandem mass spectrometry in MRM mode, and quantified by external matrix-matched standard calibration. The cycle time of each analysis was 5.5 min. The calibration curves were linear in the range of 0.3-100 ng/mL of the glycoalkaloids in plasma and urine. The correlation coefficients were 0.997-0.999. The limits of detection (S/N = 3) and quantitation (S/N = 10) were 0.1 ng/mL and 0.3 ng/mL. The average recoveries were 82%-112% and 96%-114% for the glycoalkaloids spiked in plasma and urine, respectively, with relative standard deviations of 4.0%-16% and 2.7%-17% (n = 6). The method is simple, accurate and sensitive to detect the glycoalkaloids in plasma and urine for both clinical and forensic purposes.

  10. A novel solid-phase extraction for the concentration of sweeteners in water and analysis by ion-pair liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Gan, Zhiwei; Sun, Hongwen; Wang, Ruonan; Feng, Biting

    2013-01-25

    A highly sensitive method for the simultaneous trace (ng/L) quantification of seven commonly used artificial sweeteners in a variety of water samples using solid-phase extraction and ion-pair high-performance liquid chromatography (HPLC) triple quadrupole mass spectrometer with an electrospray ionization source (ESI-MS) in negative ion multiple reaction monitoring mode was developed. Ten solid phase extraction (SPE) cartridges were tested to evaluate their applicability for the pre-concentration of the analytes, and their loading and eluting parameters were optimized. Satisfactory recoveries (77-99%) of all of the studied sweeteners were obtained using a Poly-Sery PWAX cartridge with 25 mM sodium acetate solution (pH 4) as wash buffer and methanol containing 1mM tris (hydroxymethyl) amino methane (TRIS) as eluent. The method is sound and does not require pH adjustment or buffering of water samples. The HPLC separation was performed on an Athena C18-WP column with water and acetonitrile, both containing 5mM ammonium acetate and 1mM TRIS as mobile phases, in gradient elution mode. The linearity, precision, and accuracy of the method were evaluated, and good reproducibility was obtained. Method quantification limits varied between 0.4 and 7.5 ng/L for different water samples. The post-extraction spike method was applied to assess matrix effects, and quantification was achieved using internal standard calibration to overcome the unavoidable matrix effects during ESI-MS analysis. The method was applied to the analysis of thirteen water samples from Tianjin, China, including wastewater, tap water, surface water, and groundwater. The method described here is time-saving, accurate and precise, and is suitable for monitoring artificial sweeteners in different water matrices.

  11. Selective determination of tobacco-specific nitrosamines in mainstream cigarette smoke by GC coupled to positive chemical ionization triple quadrupole MS.

    Science.gov (United States)

    Wu, Da; Lu, Yifeng; Lin, Huaqing; Zhou, Wanhong; Gu, Wenbo

    2013-08-01

    A rapid method for the selective determination of four kinds of tobacco-specific nitrosamines, N-nitrosonornicotine, N-nitrosoanatabine, N-nitrosoanabasine and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone, in mainstream cigarette smoke was developed by GC coupled to positive chemical ionization triple-quadrupole MS. After mainstream cigarette smoke was collected on a cambridge filter pad, the particulate matter was extracted with 0.1 M HCL aqueous solution, cleaned by positive cation-exchange solid extraction, and finally injected into GC-MS/MS using isotopically labeled analogues as internal standards. Excellent linearity was obtained over the concentration range of 0.5-200.0 ng mL(-1) for all tobacco-specific nitrosamines with values for correlation coefficient between 0.9996-0.9999. Limits of detection of each tobacco specific nitrosamine varied from 0.023-0.028 ng cig(-1), and lower limits of quantification varied from 0.077-0.093 ng cig(-1). The recovery of each tobacco specific nitrosamine was from 90.0-109.0%. The relative standard deviations of the intra-day and inter-day precisions were 3.1-5.8 and 3.9-6.6, respectively. This method was applied to reference and domestic cigarettes. The result showed that the method was consistent with traditional methods and can be used as an effective approach for the routine analysis of tobacco-specific nitrosamines. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Screening of drugs and toxic compounds with liquid chromatography-linear ion trap tandem mass spectrometry.

    Science.gov (United States)

    Sauvage, François-Ludovic; Saint-Marcoux, Franck; Duretz, Bénédicte; Deporte, Didier; Lachatre, Gérard; Marquet, Pierre

    2006-09-01

    In clinical and forensic toxicology, general unknown screening is used to detect and identify exogenous compounds. In this study, we aimed to develop a comprehensive general unknown screening method based on liquid chromatography coupled with a hybrid triple-quadrupole linear ion trap mass spectrometer. After solid-phase extraction, separation was performed using gradient reversed-phase chromatography. The mass spectrometer was operated in the information-dependent acquisition mode, switching between a survey scan acquired in the Enhanced Mass Spectrometry mode with dynamic subtraction of background noise and a dependent scan obtained in the enhanced product ion scan mode. The complete cycle time was 1.36 s. A library of 1000 enhanced product ion-tandem mass spectrometry spectra in positive mode and 250 in negative mode, generated using 3 alternated collision tensions during each scan, was created by injecting pure solutions of drugs and toxic compounds. Comparison with HPLC-diode array detection and gas chromatography-mass spectrometry for the analysis of 36 clinical samples showed that linear ion trap tandem mass spectrometry could identify most of the compounds (94% of the total). Some compounds were detected only by 1 of the other 2 techniques. Specific clinical cases highlighted the advantages and limitations of the method. A unique combination of new operating modes provided by hybrid triple-quadrupole linear ion trap mass spectrometers and new software features allowed development of a comprehensive and efficient method for the general unknown screening of drugs and toxic compounds in blood or urine.

  13. Qualitative identification of dibenzoylmethane in licorice root (Glycyrrhiza glabra) using gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Mancia, Marisela D; Reid, Michelle E; DuBose, Evan S; Campbell, James A; Jackson, Kimberly M

    2014-01-01

    Licorice root (Glycyrrhiza glabra), an herbal Chinese medicine, has shown medicinal uses in therapeutics and cancer prevention. Dibenzoylmethane (DBM; 1, 3-diphenyl-1, 3-propadinedione), a small beta-diketone, has been reported to be a minor constituent of licorice and a known deregulator of the human prostate cancer cell cycle. Characterization of the phytochemical profiles of licorice root forms including commercially available DBM will advance our search in identifying novel reagents for prostate cancer therapeutics. Gas chromatography- triple quadrupole-mass spectrometric analysis was used for detecting DBM in licorice root extracts. DBM and all licorice forms exhibited a component with a retention time of 14.5 minutes. The major fragment ions detected were at m/z 77, 105, 147, 223 and 224 at the identified retention time by selected reaction monitoring/SRM. These data confirm the presence of DBM from its natural source (G. glabra), and the GC-MS/SRM method helps in the identification of this minor component in a complex biological matrix.

  14. Trace determination of 13 haloacetamides in drinking water using liquid chromatography triple quadrupole mass spectrometry with atmospheric pressure chemical ionization.

    Science.gov (United States)

    Chu, Wenhai; Gao, Naiyun; Yin, Daqiang; Krasner, Stuart W; Templeton, Michael R

    2012-04-27

    The haloacetamides (HAcAms) are disinfection by-products (DBPs) in drinking water which are currently receiving increased scientific attention due to their elevated toxicity relative to regulated disinfection by-products. A simultaneous determination method of 13 HAcAms, combining solid-phase extraction (SPE) enrichment, liquid chromatographic (LC) separation, and triple quadrupole mass spectrometry (tqMS) detection with atmospheric pressure chemical ionization (APCI) using selective reaction monitoring in positive mode, was developed to measure HAcAms, including chlorinated, brominated, and iodinated analogs. Ammonium chloride and Oasis HLB were selected as the dechlorinating reagent and polymeric SPE sorbent of HAcAm samples. The used tqMS apparatus showed higher sensitivity for the studied HAcAms in the APCI mode than electrospray ionization. 13 HAcAms were separated by LC in 9.0 min, and the detection limits ranged from 7.6 to 19.7 ng/L. The SPE-LC/tqMS method was successfully applied to quantify 13 HAcAms in drinking water samples for the first time, and first indentified tribromoacetamide and chloroiodoacetamide as DBPs in drinking water.

  15. Paired-ion electrospray ionization--triple quadrupole tandem mass spectrometry for quantification of anionic surfactants in waters.

    Science.gov (United States)

    Santos, Inês C; Guo, Hongyue; Mesquita, Raquel B R; Rangel, António O S S; Armstrong, Daniel W; Schug, Kevin A

    2015-10-01

    A new paired ion electrospray ionization tandem mass spectrometry method for determination of anionic surfactants in water samples was developed. In this method, dicationic ion-pairing reagents were complexed with monoanionic analytes to facilitate analyte detection in positive mode electrospray ionization - mass spectrometry. Single ion monitoring and selected reaction monitoring on a triple quadrupole instrument were performed and compared. Four dicationic reagents were tested for the determination of perfluorooctanoic acid (PFOA), perfluorooctane sulfonate (PFOS), sodium dodecyl sulfate (SDS), dodecylbenzene sulfonic acid (DBS), and stearic acid (SA), among other common anions. The obtained limits of detection were compared with those from previous literature. Solid phase extraction using a C18 cartridge was performed in order to eliminate matrix interferences. A literature review was compiled for the methods published between 2010 and 2015 for determination of anionic surfactants. The optimized method was more sensitive than previously developed methods with LOD values of 2.35, 35.4, 37.0, 1.68, and 0.675 pg for SDS, SA, DBS, PFOS, and PFOA, respectively. The developed method was effectively applied for the determination of anionic surfactants in different water samples such as bottled drinking water, cooking water, tap water, and wastewater.

  16. Determinations of airborne synthetic musks by polyurethane foam coupled with triple quadrupole gas chromatography tandem mass spectrometer.

    Science.gov (United States)

    Wang, I-Ting Ivy; Cheng, Shu-Fang; Tsai, Shih-Wei

    2014-02-21

    Synthetic musk is widely used in various scented consumer products. However, the exposure via inhalation is often ignored due to pleasant smells. In addition, the information regarding the distribution of synthetic musk in air is limited. Hence, this research is aimed to develop a highly sensitive and widely applicable method for the determination of airborne synthetic musk. In this study, polyurethane foam (PUF) and filter were employed for active air sampling. Microwave assisted extraction (MAE) and nitrogen evaporator were performed for sample preparation. A gas chromatography coupled with triple quadrupole tandem mass spectrometer (GC/MS-MS) with specific multiple reaction monitoring (MRM) transition pairs was applied for sample analysis. Compared with using selected ion monitoring (SIM) mode traditionally, the sensitivities were improved in this study about an order at least. In terms of air concentration, as low as 0.48ngm(-3) can be determined when sampling at 3.5Lmin(-1) for 8h. The method established was further applied to the analysis of synthetic musk compounds in air samples collected in a cosmetics plant. The results showed that the airborne concentrations of gaseous polycyclic musk, gaseous nitro-musk, and particle-phase polycyclic musk were 6.4×10(2), 4.0×10(1) and 3.1×10(2)ngm(-3), respectively. Meanwhile, Cashmeran, Celstolide, Galaxolide, and Tonalide were found as the dominant musk compounds in the factory investigated.

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

    Science.gov (United States)

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

    2014-01-01

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

  18. A new method for quantifying N-nitrosamines in wastewater samples by gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Yoon, Suchul; Nakada, Norihide; Tanaka, Hiroaki

    2012-08-15

    We developed a methodology for the separation, identification, and quantification of eight N-nitrosamines. For a range of wastewater samples, including raw sewage and final-discharge wastewater, the methodology, which was based on solid-phase extraction (SPE) and a purification technique followed by analysis using a gas chromatograph equipped with a triple-quadrupole mass spectrometer, gave effective separation of the targeted compounds. The limits of detection of this method for N-nitrosamines in wastewaters ranged from 0.1 to 1.0 ng L(-1) and the limits of quantification ranged from 0.4 to 3.3 ng L(-1). As a result of preliminary recovery testing, we decided on a combination of two types of sorbent cartridges for SPE-one was aminoprophyl for sample purification and the other was activated charcoal for analyte concentration-that gave excellent recovery rates (98% to 152%) of three deuterided nitrosamines (surrogates). Using this combination of SPE, internal surrogates, and an injection surrogate, we obtained good recovery rates (80% to 131%) with low relative standard deviations (1% to 14%, n=3) for eight N-nitrosamines in all samples of influent, secondary effluent, and final discharge. We applied the newly developed pre-treatment method to an influent wastewater samples. All of the N-nitrosamines except two (NMEA and NDPA) were detected in the influent sample, at 1 to 1057 ng L(-1).

  19. Characterization and performance of MALDI on a triple quadrupole mass spectrometer for analysis and quantification of small molecules.

    Science.gov (United States)

    Gobey, Jason; Cole, Mark; Janiszewski, John; Covey, Thomas; Chau, Tung; Kovarik, Peter; Corr, Jay

    2005-09-01

    The usefulness of MALDI for small-molecule work has been limited by matrix chemical interference in the mass range of interest, tedious sample preparation, and various crystallization and sample deposition issues. We report instrument characterization and small-molecule quantification performance data from a high repetition rate laser MALDI ion source coupled to a triple quadrupole mass spectrometer. The high repetition rate laser improves sensitivity and precision and allows a proportional increase in sample throughput. Tandem mass spectrometry is used to discriminate the signal from the high chemical background caused by the MALDI matrix. Successful quantification requires use of an internal standard and a means of sample cleanup for typical in vitro sample compositions. This instrument combination and analysis technique is relatively insensitive to sample crystal quality and spot homogeneity. Quantitative performance results are characterized for 53 small-molecule pharmaceutical compounds and compared to those obtained by ESI-MS/MS. Further comparison between MALDI and ESI is examined, and the potential for high-throughput MALDI-MS/MS quantification is demonstrated.

  20. Determination of parabens in environmental solid samples by ultrasonic-assisted extraction and liquid chromatography with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Núñez, L; Tadeo, J L; García-Valcárcel, A I; Turiel, E

    2008-12-19

    Analysis of various p-hydroxybenzoic esters (methyl, ethyl, isopropyl, propyl, benzyl, and butylparaben) in environmental solid samples was carried out by sonication-assisted extraction in small columns (SAESC) followed by liquid chromatography with triple quadrupole mass spectrometry (MS/MS). Solid samples were placed in small glass columns and extraction performed assisted by sonication in two consecutive steps of 15 min using acetonitrile as extraction solvent. Sample extracts were evaporated under nitrogen stream to 1 ml and analysed by LC-MS/MS. Satisfactory recoveries were obtained ranging from 83% to 110% depending on the analyte. Good limits of quantification (LOQs), between 0.11 and 0.49 ng g(-1) were obtained for LC-MS/MS, making this technique suitable for the determination of parabens in environmental solid samples, particularly at trace level. The developed method was applied to the determination of target analytes in different types of soil and sediments, finding levels between LOD and 6.35 ng g(-1).

  1. Targeted comparative proteomics by liquid chromatography/matrix-assisted laser desorption/ionization triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Melanson, Jeremy E; Chisholm, Kenneth A; Pinto, Devanand M

    2006-01-01

    Here we report the first application of a matrix-assisted laser desorption/ionization (MALDI) triple-quadrupole mass spectrometer for targeted proteomics. Employing an amine-specific isotopic labelling approach, the technique was validated using five randomly selected bovine serum albumin peptides differentially labelled at known ratios. An indirect benefit of the isotopic labelling technique is a significant enhancement of the a1 ion in tandem mass (MS/MS) spectra of all peptides studied. Therefore, the a1 ion was selected as the fragment ion for multiple reaction monitoring (MRM) in all cases, eliminating tedious method development and optimization. Accurate quantification was achieved with an average relative standard deviation (RSD) of 5% (n = 5) and a detection limit of 14 amol. The technique was then applied to validate an important virulence biomarker of the fungal pathogen Candida albicans, which was not accurately quantified using global proteomics experiment employing two-dimensional liquid chromatography/electrospray ionization tandem mass spectrometry (2D-LC/ESI)-MS/MS. Using LC/MALDI-MRM analysis of five tryptic peptides, the protein PHR1 was found to be upregulated in the hyphal (pathogenic) form of C. albicans by a factor of 7.7 +/- 0.8.

  2. Qualitative analysis of seized synthetic cannabinoids and synthetic cathinones by gas chromatography triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Gwak, Seongshin; Arroyo-Mora, Luis E; Almirall, José R

    2015-02-01

    Designer drugs are analogues or derivatives of illicit drugs with a modification of their chemical structure in order to circumvent current legislation for controlled substances. Designer drugs of abuse have increased dramatically in popularity all over the world for the past couple of years. Currently, the qualitative seized-drug analysis is mainly performed by gas chromatography-electron ionization-mass spectrometry (GC-EI-MS) in which most of these emerging designer drug derivatives are extensively fragmented not presenting a molecular ion in their mass spectra. The absence of molecular ion and/or similar fragmentation pattern among these derivatives may cause the equivocal identification of unknown seized-substances. In this study, the qualitative identification of 34 designer drugs, mainly synthetic cannabinoids and synthetic cathinones, were performed by gas chromatography-triple quadrupole-tandem mass spectrometry with two different ionization techniques, including electron ionization (EI) and chemical ionization (CI) only focusing on qualitative seized-drug analysis, not from the toxicological point of view. The implementation of CI source facilitates the determination of molecular mass and the identification of seized designer drugs. Developed multiple reaction monitoring (MRM) mode may increase sensitivity and selectivity in the analysis of seized designer drugs. In addition, CI mass spectra and MRM mass spectra of these designer drug derivatives can be used as a potential supplemental database along with EI mass spectral database. Copyright © 2014 John Wiley & Sons, Ltd.

  3. Determination of polycyclic aromatic hydrocarbons in soy isoflavone nutraceutical products by gas chromatography coupled to triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Ruiz-Delgado, Ana; Martínez-Domínguez, Gerardo; Romero-González, Roberto; López-Ruiz, Rosalía; Frenich, Antonia Garrido

    2016-02-01

    Thirteen polycyclic aromatic hydrocarbons have been determined in soy-based nutraceutical products. First, an optimization of extraction procedure was performed, and a solid-liquid extraction assisted by sonication and a dilute and shoot procedure were compared, selecting the dilute and shoot approach for the extraction of target compounds, utilizing a mixture of acetone/n-hexane (1:1 v/v) as extractant solvent. After this, a clean-up step was needed bearing in mind the complexity of these matrices. Dispersive solid-phase extraction, using a mixture of C18 and Zr-Sep+ (25 mg/mL each) was used. The separation was achieved by gas chromatography and detection with triple quadrupole tandem mass spectrometry. For quantification purposes, matrix-matched calibration was used. The validation was applied at three concentration levels (20, 100 and 250 μg/kg), obtaining recoveries between 70 and 120% and precision values equal to or lower than 23%. Limits of detection and quantification were below 8 and 20 μg/kg, respectively. The method was applied in 11 samples, detecting five polycyclic aromatic hydrocarbons at concentrations ranging from 4.1 to 18.5 μg/kg.

  4. Determination of polychlorinated biphenyls in ambient air by gas chromatography coupled to triple quadrupole tandem mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Martinez Ocana, Rosa; Mena Granero, Angela; Egea Gonzalez, Francisco J.; Garrido Frenich, Antonia; Martinez Vidal, Jose L.; Plaza Bolanos, Patricia [University of Almeria, Department of Analytical Chemistry, Almeria (Spain)

    2008-03-15

    A multiresidue method for determining 22 polychlorinated biphenyls (PCBs) in air has been developed and validated by gas chromatography (GC) coupled to tandem mass spectrometry (MS/MS) using a triple quadrupole analyzer (QqQ). The method was validated in terms of both steps of sampling and analysis. The sampling method, which is based on active sampling using polyurethane foam (PUF) as adsorbent, was validated by generating standard atmospheres. The retention capacity of this sampling sorbent allows up to 5 m{sup 3} of air to be sampled without any breakthrough for most compounds. Two solvent extraction methods were compared: sonication and Soxhlet extraction with a mixture of n-hexane:diethyl ether (95:5 v/v). Both extraction methods yielded similar results, but the first one required less solvent and time. The method exhibited good accuracy (80.3-99.8%), precision (2.2-15.2%) and lower limits that allowed quantification and confirmation at levels as low as 0.008 ng/m{sup 3}. Finally, the method was applied to the analysis of PCBs in the air in areas near to a municipal solid-waste landfill and directly above the refuse in the landfill, where it indicated the presence of some of the target compounds. (orig.)

  5. A HYBRID METHOD FOR LINEAR PROGRAMMING

    Institute of Scientific and Technical Information of China (English)

    XIU Naihua; WU Fang

    1999-01-01

    In this paper, a hybrid method for linear programming is established.Its search direction is defined as a combination of two directions insimplex method and affine-scaling interior point method.The method is proven to have some promising convergence properties.The relation among the new method, the simplex method and the affine-scalinginteriorpoint method is discussed.

  6. Investigations in the possibility of early detection of colorectal cancer by gas chromatography/triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Nishiumi, Shin; Kobayashi, Takashi; Kawana, Shuichi; Unno, Yumi; Sakai, Takero; Okamoto, Koji; Yamada, Yasuhide; Sudo, Kazuki; Yamaji, Taiki; Saito, Yutaka; Kanemitsu, Yukihide; Okita, Natsuko Tsuda; Saito, Hiroshi; Tsugane, Shoichiro; Azuma, Takeshi; Ojima, Noriyuki; Yoshida, Masaru

    2017-03-07

    In developed countries, the number of patients with colorectal cancer has been increasing, and colorectal cancer is one of the most common causes of cancer death. To improve the quality of life of colorectal cancer patients, it is necessary to establish novel screening methods that would allow early detection of colorectal cancer. We performed metabolome analysis of a plasma sample set from 282 stage 0/I/II colorectal cancer patients and 291 healthy volunteers using gas chromatography/triple-quadrupole mass spectrometry in an attempt to identify metabolite biomarkers of stage 0/I/II colorectal cancer. The colorectal cancer patients included patients with stage 0 (N=79), I (N=80), and II (N=123) in whom invasion and metastasis were absent. Our analytical system detected 64 metabolites in the plasma samples, and the levels of 29 metabolites differed significantly (Bonferroni-corrected p=0.000781) between the patients and healthy volunteers. Based on these results, a multiple logistic regression analysis of various metabolite biomarkers was carried out, and a stage 0/I/II colorectal cancer prediction model was established. The area under the curve, sensitivity, and specificity values of this model for detecting stage 0/I/II colorectal cancer were 0.996, 99.3%, and 93.8%, respectively. The model's sensitivity and specificity values for each disease stage were >90%, and surprisingly, its sensitivity for stage 0, specificity for stage 0, and sensitivity for stage II disease were all 100%. Our predictive model can aid early detection of colorectal cancer and has potential as a novel screening test for cases of colorectal cancer that do not involve lymph node or distant metastasis.

  7. [Qualitative and quantitative analysis of amygdalin and its metabolite prunasin in plasma by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry].

    Science.gov (United States)

    Gao, Meng; Wang, Yuesheng; Wei, Huizhen; Ouyang, Hui; He, Mingzhen; Zeng, Lianqing; Shen, Fengyun; Guo, Qiang; Rao, Yi

    2014-06-01

    A method was developed for the determination of amygdalin and its metabolite prunasin in rat plasma after intragastric administration of Maxing shigan decoction. The analytes were identified by ultra-high performance liquid chromatography-tandem quadrupole time of flight mass spectrometry and quantitatively determined by ultra-high performance liquid chromatography-tandem triple quadrupole mass spectrometry. After purified by liquid-liquid extraction, the qualitative analysis of amygdalin and prunasin in the plasma sample was performed on a Shim-pack XR-ODS III HPLC column (75 mm x 2.0 mm, 1.6 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on a Triple TOF 5600 quadrupole time of flight mass spectrometer. The quantitative analysis of amygdalin and prunasin in the plasma sample was performed by separation on an Agilent C18 HPLC column (50 mm x 2.1 mm, 1.7 microm), using acetonitrile-0.1% (v/v) formic acid aqueous solution. The detection was performed on an AB Q-TRAP 4500 triple quadrupole mass spectrometer utilizing electrospray ionization (ESI) interface operated in negative ion mode and multiple-reaction monitoring (MRM) mode. The qualitative analysis results showed that amygdalin and its metabolite prunasin were detected in the plasma sample. The quantitative analysis results showed that the linear range of amygdalin was 1.05-4 200 ng/mL with the correlation coefficient of 0.999 0 and the linear range of prunasin was 1.25-2 490 ng/mL with the correlation coefficient of 0.997 0. The method had a good precision with the relative standard deviations (RSDs) lower than 9.20% and the overall recoveries varied from 82.33% to 95.25%. The limits of detection (LODs) of amygdalin and prunasin were 0.50 ng/mL. With good reproducibility, the method is simple, fast and effective for the qualitative and quantitative analysis of the amygdalin and prunasin in plasma sample of rats which were administered by Maxing shigan decoction.

  8. Identification and quantification of the anti-inflammatory constituents in Pian-Tze-Huang by liquid chromatography combined with quadrupole time-of-flight and triple quadrupole mass spectrometry.

    Science.gov (United States)

    Huang, Mingqing; Xu, Wen; Zhang, Yiping; Liu, Jie; Zhang, Xiaoqin; Lin, Jing; Peng, Jun; Lu, Jinjian

    2016-08-01

    Both qualitative and quantitative analyses combined with activity evaluation were used for the integrated quality control study of Pien-Tze-Huang (PZH), a precious lozenge used for 460 years in China. In qualitative analysis, a high performance LC-quadrupole time-of-flight MS method was developed for the identification of chemical profiling in PZH. 27 compounds were unambiguously identified by comparing with reference substances, and 12 compounds were tentatively deduced based on their MS data and comparing with literatures. Then the in vitro anti-inflammatory activity of 27 compounds were evaluated, and 9 saponins, 11 bile acids, taurine and muscone exhibited significant inhibitory activities on TNF-α production with IC50 values ranging from 12.34 to 147.24μM. In quantitative analysis, 21 active compounds, selected as quality control markers, were simultaneously detected in 15 batches of PZH samples by ultra-performance LC-triple quadrupole MS. All the analytes were detected within 15min. Satisfactory linearity was achieved with wide linear range and fine determination coefficient (r(2)>0.9990). The respective relative standard deviations of intra- and inter-day precisions, repeatability, stability, and recovery were less than 4.32%, 4.94%, 4.78%, 4.87%, and 4.91%. This study established a high sensitive and efficient method for the integrated quality control of PZH, including qualitative and quantitative analyses combined with pharmacological activity evaluation.

  9. Comprehensive profiling of N-acylhomoserine lactones produced by Yersinia pseudotuberculosis using liquid chromatography coupled to hybrid quadrupole-linear ion trap mass spectrometry.

    Science.gov (United States)

    Ortori, Catharine A; Atkinson, Steve; Chhabra, Siri Ram; Cámara, Miguel; Williams, Paul; Barrett, David A

    2007-01-01

    A method for the comprehensive profiling of the N-acylhomoserine lactone (AHL) family of bacterial quorum-sensing molecules is presented using liquid chromatography (LC) coupled to hybrid quadrupole-linear ion trap (QqQLIT) mass spectrometry. Information-dependent acquisition (IDA), using triggered combinations of triple-quadrupole and linear ion trap modes in the same LC-MS/MS run, was used to simultaneously screen, quantify and identify multiple AHLs in a single sample. This MS method uses common AHL fragment ions attributed to the homoserine moiety and the 3-oxo-, 3-hydroxy- or unsubstituted acyl side chains, to identify unknown AHLs in cell-free culture supernatants in an unbiased manner. This LC-MS technique was applied to determine the relative molar ratios of AHLs produced by Yersinia pseudotuberculosis and the consequences of inactivating by mutation either or both of the AHL synthase genes (ypsI and ytbI) on AHL profile and concentration. The Y. pseudotuberculosis wild type but not the ypsI ytbI double mutant produced at least 24 different AHLs with acyl chains ranging from C4 to C15 with or without 3-oxo or 3-hydroxy substituents. YtbI, in contrast to YpsI, could direct the synthesis of all of the AHLs identified. The most abundant and hence most biologically relevant Y. pseudotuberculosis AHLs were found to be the 3-oxo-substituted C6, C7 and C8 AHLs and the unsubstituted C6 and C8 compounds. The LC-QqQLIT methodology is broadly applicable to quorum-sensing signal molecule analysis and can provide comprehensive AHL profiles and concentrations from a single sample and simultaneously collect confirmatory spectra for each AHL identified.

  10. Detection of Gelatin Adulteration in Traditional Chinese Medicine: Analysis of Deer-Horn Glue by Rapid-Resolution Liquid Chromatography-Triple Quadrupole Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Jia Chen

    2015-01-01

    Full Text Available Simultaneous identification of donkey-hide gelatin and bovine-hide gelatin in deer-horn glue was established by rapid-resolution liquid chromatography-triple quadrupole mass spectrometry. Water containing 1% NH4HCO3 was used for sample dissolution and trypsin was used for hydrolysis of the gelatins. After separation by a SB-C18 reversed-phase analytical column, collagen marker peptides were detected by mass spectrometry in positive electrospray ionization mode with multiple reaction monitoring. The method was specific, precise and reliable, and suitable for detection of adulterants derived from donkey-hide gelatin and bovine-hide gelatin in deer-horn glue.

  11. High performance solid-phase extraction cleanup method coupled with gas chromatography-triple quadrupole mass spectrometry for analysis of polychlorinated naphthalenes and dioxin-like polychlorinated biphenyls in complex samples.

    Science.gov (United States)

    Li, Fang; Jin, Jing; Tan, Dongqin; Xu, Jiazhi; Dhanjai; Ni, Yuwen; Zhang, Haijun; Chen, Jiping

    2016-05-27

    A solid-phase extraction (SPE) cleanup method was developed to purify the sample extracts for the analysis of polychlorinated naphthalenes (PCNs) and dioxin-like polychlorinated biphenyls (dl-PCBs). Monodisperse magnesium oxide (MgO) microspheres and basic alumina were used as SPE adsorbents. Important parameters of the SPE procedure were optimized, including the amount of basic alumina and the type and volume of the washing and elution solvents. The optimized SPE cleanup method exhibited excellent purification performance for the removal of organochlorinated compounds, lipid compounds, sulfur, and pigments. Additionally, it was found that the retention activities of congeners differed with the number and position of the chlorine substituents in PCNs. In this study, an analytical method based on a combination of accelerated solvent extraction (ASE) coupled with SPE cleanup and gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS) is proposed for the analysis of PCNs and dl-PCBs in complex samples (sediment, pine needle, and scallop samples). The analytical method demonstrates good linearity, acceptable recovery (63-148%) and precision (relative standard deviations less than 26%). The limits of detection (LODs) of PCN and dl-PCB congeners were in the range of 0.6-19.1pgg(-1) and 0.4-8.6pgg(-1), respectively. The PCNs and dl-PCBs levels in these samples ranged from 0.16 to 3.07ngg(-1) dry weight (dw) and from undetectable to 0.07ngg(-1) dw, respectively.

  12. Simultaneous Quantification of Flavonol Glycosides, Terpene Lactones, Biflavones, Proanthocyanidins, and Ginkgolic Acids in Ginkgo biloba Leaves from Fruit Cultivars by Ultrahigh-Performance Liquid Chromatography Coupled with Triple Quadrupole Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Xin Yao

    2013-01-01

    Full Text Available On the basis of liquid chromatography coupled with triple quadrupole mass spectrometry working in multiple reaction monitoring mode, an analytical method has been established to simultaneously determine flavonol glycosides, terpene lactones, biflavones, proanthocyanidins, and ginkgolic acids in Ginkgo biloba leaves. Chromatographic separation was carried out on an Acquity BEH C18 column (100 mm × 2.1 mm, 1.7 μm with gradient elution of acetonitrile and 0.10% formic acid (v/v at a flow rate of 0.4 mL/min, and column temperature 30°C. The developed method was validated in terms of linearity, accuracy, precision, stability, and sensitivity. The optimized method was successfully applied to analyze twenty-two G. biloba leaf samples of fruit cultivars collected from different places in China. Furthermore, hierarchical clustering analysis (HCA was performed to evaluate and classify the samples according to the contents of the twenty-four chemical constituents. All of the results demonstrated that the developed method was useful for the overall evaluation of the quality of G. biloba leaves, and this study was also helpful for the comprehensive utilization and development of G. biloba resources.

  13. Determination of RH-5849 and indoxacarb in rice straw, rice husk, brown rice and soil using liquid chromatography-tandem triple quadrupole mass spectrometry following extraction with QuEChERS method.

    Science.gov (United States)

    Li, Zhurui; Zhao, Xiaozhen; Chen, Jiaojiao; Wu, Yue; Zhang, Jing; Zhang, Kankan; Hu, Deyu

    2016-10-01

    A fast and simple analytical method was developed for the simultaneous determination of RH-5849 and indoxacarb in soil, rice straw, rice husk and brown rice. QuEChERS (quick, easy, cheap, effective, rugged and safe) method was used for extraction, and liquid chromatography with tandem triple quadrupole mass spectrometry was used for quantification. The matrix-matched calibration plots were linear in the range between 25 and 5000 μg/L for soil, rice straw, rice husk and brown rice samples. All determination coefficients (R(2) ) were ≥0.9962. The limits of detection and quantification were 1.5 and 5 μg/kg, respectively. Recoveries at three fortification levels ranged between 79.5 and 97.9% with relative standard deviations <11%. The developed method was validated and applied for the analysis of dissipation study samples. For field experiments, the half-lives of RH-5849 and indoxacarb in rice straw were 11.93 and 5.83 days, respectively. The method was demonstrated to be reliable for the routine monitoring of RH-5849 and indoxacarb in rice samples. Copyright © 2016 John Wiley & Sons, Ltd.

  14. Chemical profiling and quantification of Gua-Lou-Gui-Zhi decoction by high performance liquid chromatography/quadrupole-time-of-flight mass spectrometry and ultra-performance liquid chromatography/triple quadrupole mass spectrometry.

    Science.gov (United States)

    Xu, Wen; Huang, Mingqing; Li, Huang; Chen, Xianwen; Zhang, Yuqin; Liu, Jie; Xu, Wei; Chu, Kedan; Chen, Lidian

    2015-04-01

    Gua-Lou-Gui-Zhi decoction (GLGZD) is a classical formula of traditional Chinese medicine, which has been commonly used to treat dysfunction after stroke, epilepsy and spinal cord injury. In this study, a systematic method was established for chemical profiling and quantification analysis of the major constituents in GLGZD. For qualitative analysis, a method of high performance liquid chromatography/quadrupole time-of-flight mass spectrometry (Q-TOF MS) was developed. 106 compounds, including monoterpene glycosides, galloyl glucoses, phenolic acids, flavonoids, gingerols and triterpene saponins were identified or tentatively presumed by comparison with reference standards or literature data. According to the qualitative results, a new quantitative analysis method of ultra-performance liquid chromatography/triple quadrupole mass spectrometry (QqQ-MS) was established. 24 representative compounds were simultaneously detected in 10 batches of GLGZD samples in 7.5 min. The calibration curves for all analytes showed good linearity (r>0.9959) within the test ranges. The LODs and the LOQs were less than 30.6 and 70.9 ng/mL, respectively. The RSDs of intra- and inter-day precision, repeatability and stability were below 3.64%, 4.85%, 4.84% and 3.87%, respectively. The overall recoveries ranged from 94.94% to 103.66%, with the RSDs within 5.12%. This study established a high sensitive and efficient method for the integrating quality control, including identification and quantification of Chinese medicinal preparation.

  15. [Ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction for the determination of eight drugs in biological samples by gas chromatography-triple quadrupole mass spectrometry].

    Science.gov (United States)

    Meng, Liang; Zhu, Binling; Zheng, Kefang; Zhang, Wenwen; Meng, Pinjia

    2015-03-01

    A novel microextraction technique based on ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction (UA-LDS-DLLME) has been developed for the determination of multiple drugs of abuse in biological samples by gas chromatography-triple quadrupole mass spectrometry (GC-QQQ-MS). A total of 100 µL of toluene as extraction solvent was dropped into the sample solution. Then the mixture was sonicated drastically in an ultrasonic bath for 3 min with occasional manual shaking to form a cloudy suspension. After centrifugation at 10,000 r/min for 3 min, the upper layer of low-density extractant was withdrawn and injected into the GC-QQQ-MS for analysis. The parameters affecting extraction efficiency have been investigated and optimized. Under the optimum conditions, good linearities were observed for all analytes with the correlation coefficients ranging from 0. 998 4 to 0. 999 4. The recoveries of 79.3%-100.3% with RSDs technique has the advantages of less extraction time, suitable for batches of sample pretreatment simultaneously, and higher extraction efficiency. It was successfully applied to the analysis of amphetamines in real human urine samples.

  16. A single marker choice strategy in simultaneous characterization and quantification of multiple components by rapid resolution liquid chromatography coupled with triple quadrupole tandem mass spectrometry (RRLC-QqQ-MS).

    Science.gov (United States)

    Ning, Zhangchi; Liu, Zhenli; Song, Zhiqian; Zhao, Siyu; Dong, Yunzhuo; Zeng, Honglian; Shu, Yisong; Lu, Cheng; Liu, Yuanyan; Lu, Aiping

    2016-05-30

    Single standard to determine multi-components (SSDMC) method has been accepted as an efficient technique for the quality control of Traditional Chinese medicines (TCMs), especially for overcoming the shortage of reference standards. HPLC-UV methods have been applied to establish SSDMC method for quantitative analysis in several plant medicines and Chinese patent medicines, however, no LC-MS methods have been used. The purpose of this study is to put forward an improved strategy for the choice of single marker in SSDMC using rapid resolution liquid chromatography coupled with triple quadrupole tandem mass spectrometry (RRLC-QqQ-MS). Five different Panax genus plants, recorded in the Chinese Pharmacopeia 2015 edition, were used as research subjects. An improved SSDMC strategy for simultaneous characterization and determination of 18 bioactive saponins in five Panax plants was put forward, and which was validated to be more superior. Then, it was fully investigated with respect to linearity, LODs, LOQs, precision and accuracy. Coupling with multivariate statistical analysis, the established and validated SSDMC strategy could be successively used in discrimination of the five Panax genus plants.

  17. General linear dynamics - quantum, classical or hybrid

    CERN Document Server

    Elze, H-T; Vallone, F

    2011-01-01

    We describe our recent proposal of a path integral formulation of classical Hamiltonian dynamics. Which leads us here to a new attempt at hybrid dynamics, which concerns the direct coupling of classical and quantum mechanical degrees of freedom. This is of practical as well as of foundational interest and no fully satisfactory solution of this problem has been established to date. Related aspects will be observed in a general linear ensemble theory, which comprises classical and quantum dynamics in the form of Liouville and von Neumann equations, respectively, as special cases. Considering the simplest object characterized by a two-dimensional state-space, we illustrate how quantum mechanics is special in several respects among possible linear generalizations.

  18. Simultaneous determination of 3-monochloropropane-1,2-diol and acrylamide in food by gas chromatography-triple quadrupole mass spectrometry with coupled column separation.

    Science.gov (United States)

    Xu, Xiao-min; He, Hua-li; Zhu, Yan; Feng, Liang; Ying, Ying; Huang, Bai-fen; Shen, Hai-tao; Han, Jian-long; Ren, Yi-ping

    2013-01-14

    Both 3-monochloropropane-1,2-diol (3-MCPD) and acrylamide are contaminants found in heat-processed foods and their related products. A quantitative method was developed for the simultaneous determination of both contaminants in food by gas chromatography-triple quadrupole mass spectrometry (GC-MS/MS). The analytes were purified and extracted by the matrix solid-phase dispersion extraction (MSPDE) technique with Extrelut NT. A coupled column (a 3 m Innowax combined with a 30 m DB-5 ms) was developed to separate both compounds efficiently without derivatization. Triple quadrupole mass spectrometry in multiple reaction monitoring mode (MRM) was applied to suppress matrix interference and obtain good sensitivity in the determination of both analytes. The limit of detection (LOD) in the sample matrix was 5 μg kg(-1) for 3-MCPD or acrylamide. The average recoveries for 3-MCPD and acrylamide in different food matrices were 90.5-107% and 81.9-95.7%, respectively, with the intraday relative standard deviations (RSDs) of 5.6-13.5% and 5.3-13.4%, respectively. The interday RSDs were 6.1-12.6% for 3-MCPD and were 5.0-12.8% for acrylamide. Both contaminants were found in samples of bread, fried chips, fried instant noodles, soy sauce, and instant noodle flavoring. Neither 3-MCPD nor acrylamide was detected in the samples of dairy products (solid or liquid samples) and non-fried instant noodles. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. CULA: hybrid GPU accelerated linear algebra routines

    Science.gov (United States)

    Humphrey, John R.; Price, Daniel K.; Spagnoli, Kyle E.; Paolini, Aaron L.; Kelmelis, Eric J.

    2010-04-01

    The modern graphics processing unit (GPU) found in many standard personal computers is a highly parallel math processor capable of nearly 1 TFLOPS peak throughput at a cost similar to a high-end CPU and an excellent FLOPS/watt ratio. High-level linear algebra operations are computationally intense, often requiring O(N3) operations and would seem a natural fit for the processing power of the GPU. Our work is on CULA, a GPU accelerated implementation of linear algebra routines. We present results from factorizations such as LU decomposition, singular value decomposition and QR decomposition along with applications like system solution and least squares. The GPU execution model featured by NVIDIA GPUs based on CUDA demands very strong parallelism, requiring between hundreds and thousands of simultaneous operations to achieve high performance. Some constructs from linear algebra map extremely well to the GPU and others map poorly. CPUs, on the other hand, do well at smaller order parallelism and perform acceptably during low-parallelism code segments. Our work addresses this via hybrid a processing model, in which the CPU and GPU work simultaneously to produce results. In many cases, this is accomplished by allowing each platform to do the work it performs most naturally.

  20. Detection of selenocompounds in a tryptic digest of yeast selenoprotein by MALDI time-of-flight MS prior to their structural analysis by electrospray ionization triple quadrupole MS.

    Science.gov (United States)

    Encinar, Jorge Ruiz; Ruzik, Rafal; Buchmann, William; Tortajada, Jeanine; Lobinski, Ryszard; Szpunar, Joanna

    2003-03-01

    MALDI-TOFMS was proposed as a key technique to a novel generic approach for the speciation analysis of selenium in yeast supplements. Owing to a lower detection limit and superior matrix tolerance to electrospray MS it allowed a successful detection of selenocompounds in samples for which electrospray MS had failed. The analytical approach developed was applied to the identification of a previously unreported selenopentapeptide (m/z 596) in the tryptic digest of a water-soluble selenoprotein fraction isolated by size-exclusion chromatography. The information on the mass of the protonated molecular ion obtained from MALDI allowed the optimization of the conditions for collision induced dissociation MS using a triple quadrupole spectrometer that enabled the determination of the amino acid sequence SeMet-Asn-Ala-Gly-Arg of the selenopeptide.

  1. Application of GC-triple quadrupole MS in the quantitative confirmation of polycyclic aromatic hydrocarbons and phthalic acid esters in soil.

    Science.gov (United States)

    Liao, Chong; Yang, Ping; Xie, Zhenwei; Zhao, Yunzhi; Cheng, Xiaoyan; Zhang, Yu; Ren, Zhaohui; Guo, Zhonghua; Liao, Ji

    2010-03-01

    A new multi-residue method has been developed and validated for the simultaneous analysis of 34 polycyclic aromatic hydrocarbons (PAHs) and phthalic acid esters (PAEs) in soil at trace levels by gas chromatography coupled to triple quadrupole mass spectrometry. Microwave extraction and solid-phase extraction have been employed prior to gas chromatography tandem mass spectrometry analysis. Quality parameters have been established using matrix spike and reference material IRM 104A. Average recoveries of the 34 organic compounds spiked at 5 microg/kg into soils are typically in the range of 66.59-122.07% with relative standard deviations generally less than 20%. Limits of detection (LODs) for PAEs are < or = 0.84 microg/kg, and limits of quantification (LOQs) ranged from 0.13 to 2.81 microg/kg. LODs for PAHs are < or = 0.51 microg/kg, and LOQs ranged from 0.02 to 1.81 microg/kg.

  2. Triple Quadrupole Versus High Resolution Quadrupole-Time-of-Flight Mass Spectrometry for Quantitative LC-MS/MS Analysis of 25-Hydroxyvitamin D in Human Serum

    Science.gov (United States)

    Geib, Timon; Sleno, Lekha; Hall, Rabea A.; Stokes, Caroline S.; Volmer, Dietrich A.

    2016-08-01

    We describe a systematic comparison of high and low resolution LC-MS/MS assays for quantification of 25-hydroxyvitamin D3 in human serum. Identical sample preparation, chromatography separations, electrospray ionization sources, precursor ion selection, and ion activation were used; the two assays differed only in the implemented final mass analyzer stage; viz. high resolution quadrupole-quadrupole-time-of-flight (QqTOF) versus low resolution triple quadrupole instruments. The results were assessed against measured concentration levels from a routine clinical chemiluminescence immunoassay. Isobaric interferences prevented the simple use of TOF-MS spectra for extraction of accurate masses and necessitated the application of collision-induced dissociation on the QqTOF platform. The two mass spectrometry assays provided very similar analytical figures of merit, reflecting the lack of relevant isobaric interferences in the MS/MS domain, and were successfully applied to determine the levels of 25-hydroxyvitamin D for patients with chronic liver disease.

  3. Qualitative and Quantitative Analysis of Major Triterpenoids in Alismatis Rhizoma by High Performance Liquid Chromatography/Diode-Array Detector/Quadrupole-Time-of-Flight Mass Spectrometry and Ultra-Performance Liquid Chromatography/Triple Quadrupole Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Wanli Zhao

    2015-07-01

    Full Text Available Alismatis Rhizoma (AMR is a well-known natural medicine with a long history in Chinese medicine and has been commonly used for treating a wide range of ailments related to dysuria, edema, nephropathy, hyperlipidaemia, diabetes, inflammation as well as tumors in clinical applications. Most beneficial effects of AMR are attributed to the presence of protostane terpenoids, the major active ingredients of Alismatis Rhizoma (AMR. In this study, a systematic high performance liquid chromatography/diode-array detector/quadrupole-time-of-flight mass spectrometry (HPLC-DAD-Q-TOF MS and ultra-performance liquid chromatography/triple quadrupole mass spectrometry (UPLC-QqQ MS method was developed for qualitative and quantitative analyses of the major AMR triterpenoids. First, a total of 25 triterpenoid components, including 24 known compounds and one new compound were identified by comparison with UV spectra, molecular ions and fragmentation behaviors of reference standards or the literature. Second, an efficient method was established for the rapid simultaneous determination of 14 representative triterpenoids by UPLC-QqQ MS. Forty-three batches of AMR were analyzed with linearity (r, 0.9980–0.9999, intra-day precision (RSD, 1.18%–3.79%, inter-day precision (RSD, 1.53%–3.96%, stability (RSD, 1.32%–3.97%, repeatability (RSD, 2.21%–4.25%, and recovery (98.11%–103.8%. These results indicated that new approaches combining HPLC-DAD-Q-TOF MS and UPLC-QqQ MS are applicable in the qualitative and quantitative analysis of AMR.

  4. ON THE STABILIZATION OF THE LINEAR HYBRID SYSTEM STRUCTURE

    Directory of Open Access Journals (Sweden)

    Kirillov

    2014-11-01

    Full Text Available The linear control hybrid system, consisting of a fi- nite set of subsystems (modes having different dimensions, is considered. The moments of reset time are determined by some complementary function – evolutionary time. This function satisfies the special complementary ordinary differential equation. The mode stabilization problem is solved for some class of piecewise linear controls. The method of stabilization relies on the set of invariant planes, the existence of which is due to the special form of the hybrid system.

  5. Multistage Fragmentation of Ion Trap Mass Spectrometry System and Pseudo-MS3 of Triple Quadrupole Mass Spectrometry Characterize Certain (E)-3-(Dimethylamino)-1-arylprop-2-en-1-ones: A Comparative Study

    OpenAIRE

    Ali S. Abdelhameed; Adnan A. Kadi; Abdel-Aziz, Hatem A.; Angawi, Rihab F.; Mohamed W. Attwa; Al-Rashood, Khalid A.

    2014-01-01

    A new approach was recently introduced to improve the structure elucidation power of tandem mass spectrometry simulating the MS3 of ion trap mass spectrometry system overcoming the different drawbacks of the latter. The fact that collision induced dissociation in the triple quadrupole mass spectrometer system provides richer fragment ions compared to those achieved in the ion trap mass spectrometer system utilizing resonance excitation. Moreover, extracting comprehensive spectra in the ion tr...

  6. Simultaneous ionization and analysis of 84 anabolic androgenic steroids in human urine using liquid chromatography-silver ion coordination ionspray/triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Kim, So-Hee; Cha, Eun-Ju; Lee, Kang Mi; Kim, Ho Jun; Kwon, Oh-Seung; Lee, Jaeick

    2014-01-01

    Metal ion coordination ionspray (M(+) CIS) ionization is a powerful technique to enhance ionization efficiency and sensitivity. In this study, we developed and validated an analytical method for simultaneous ionization and analysis of 84 anabolic androgenic steroids (65 exogenous and 19 endogenous) using liquid chromatography-silver ion coordination ionspray/triple-quadrupole mass spectrometry (LC-Ag(+) CIS/MS/MS). The concentrations of silver ions and organic solvents have been optimized to increase the amount of silver ion coordinated complexes. A combination of 25 μM of silver ions and methanol showed the best sensitivity. The validation results showed the intra- (0.8-9.2%) and inter-day (2.5-14.9%) precisions, limits of detection (0.0005-5.0 ng/mL), and matrix effect (71.8-100.3%) for the screening analysis. No significant ion suppression was observed. In addition, this method was successfully applied to analysis of positive samples from suspected abusers and useful for the detection of the trace levels of anabolic steroids in human urine samples.

  7. Quantitative determination of un-derivatised amino acids in artistic mural paintings using high-performance liquid chromatography/electrospray ionization triple quadrupole mass spectrometry.

    Science.gov (United States)

    Zangrando, Roberta; Piazza, Rossano; Cairns, Warren R L; Izzo, Francesca C; Vianello, Alvise; Zendri, Elisabetta; Gambaro, Andrea

    2010-08-18

    The tempera painting technique is one of the most common methods used throughout art history. Tempera is defined by the type of binders used and in this work we study protein-based temperas. Proteinaceous binders can be characterized by the chromatographic determination of the amino acids present where techniques are either based on gas chromatography or high-performance liquid chromatography (HPLC) coupled to mass spectrometry. The objective of this work was to develop a derivatisation-free HPLC method with triple quadrupole tandem mass spectrometric detection (HPLC/ESI-MS/MS) of 21 amino acids contained in the protein-based binders of tempera paints. The analytical method identifies the painting techniques of two contemporary artists: Sironi and DeLuigi. The sample data are compared to painting material standards. The results show that the samples from works by DeLuigi contain mainly animal glue binders, while the samples from Sironi paintings contain binders that are an amino acid mixture with an overall composition between that of eggs and casein.

  8. Liquid chromatography with triple-quadrupole or quadrupole-time of flight mass spectrometry for screening and confirmation of residues of pharmaceuticals in water.

    Science.gov (United States)

    Stolker, Alida A M; Niesing, Willem; Hogendoorn, Elbert A; Versteegh, Johanna F M; Fuchs, Regine; Brinkman, Udo A Th

    2004-02-01

    LC-MS-MS has been performed with triple-quadrupole (QqQ) and quadrupole-time of flight (Q-ToF) instruments and has been used for screening and confirmation of pharmaceuticals in surface, drinking, and ground water. Screening was based on monitoring of one specific MS-MS ion of the target compounds. Confirmation of the identity of the pharmaceuticals was based either on the monitoring of two specific MS-MS ions and calculation of the ratio of their intensities, or on the exact masses of MS-MS product ions obtained for a molecular ion by use of LC-Q-ToF MS. The set of pharmaceuticals included four analgesics (acetylsalicylic acid, diclofenac, ibuprofen, and paracetamol), three antibiotics (sulfamethoxazole, erythromycin, and chloramphenicol), five blood-lipid regulators and beta-blockers (fenofibrate, bezafibrate, clofibric acid, bisoprolol, and metoprolol), and the anti-epileptic drug carbamazepine. Limits of quantification ranged from 5 to 25 ng L(-1). Fifty-six samples were analysed and residues of the pharmaceuticals were detected in almost all surface and groundwater and in some drinking water samples. The identity of the compounds could be confirmed by use of both QqQ- and Q-ToF-based LC-MS-MS. However, the latter technique has the distinct advantage that a large number of pharmaceuticals can be screened and confirmed at low concentrations (1-100 ng L(-1)) in one run.

  9. Rapid determination of amino acids in fruits of Ziziphus jujuba by hydrophilic interaction ultra-high-performance liquid chromatography coupled with triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Guo, Sheng; Duan, Jin-ao; Qian, Dawei; Tang, Yuping; Qian, Yefei; Wu, Dawei; Su, Shulan; Shang, Erxin

    2013-03-20

    In this study, a sensitive and rapid method for the simultaneous determination of free amino acids without derivatization using hydrophilic interaction liquid chromatography coupled with tandem mass spectrometry (HILIC-MS/MS) was developed. The method was performed on an ultra-high-performance liquid chromatography (UHPLC) separation system coupled with a triple-quadrupole mass spectrometry (TQ-MS) instrument. Sufficient separation of 23 underivatized amino acids was achieved on an Acquity BEH Amide column (2.1 mm × 100 mm, 1.7 μm) in a single run of 12 min. Then the method was applied for the analysis of the free amino acids in 46 batches of Ziziphus jujuba fruits which comprised 39 cultivars from 26 cultivation regions. Multivariate statistical analysis was also used to investigate the differences in free amino acid profiles among the samples. This study showed that HILIC-UHPLC-TQ-MS is an effective technique to analyze underivatized amino acids in the food samples.

  10. Multi-class pesticide analysis in human hair by gas chromatography tandem (triple quadrupole) mass spectrometry with solid phase microextraction and liquid injection.

    Science.gov (United States)

    Salquèbre, Guillaume; Schummer, Claude; Millet, Maurice; Briand, Olivier; Appenzeller, Brice M R

    2012-01-13

    A method for the simultaneous detection and quantification of 22 pesticides from different chemical classes was developed using solid-phase microextraction (SPME) and gas chromatography tandem (triple quadrupole) mass spectrometry. Pesticides were extracted from 50mg of pulverized hair with acetonitrile. The extract was submitted to two successive steps of direct immersion-SPME at 30°C and 90°C or to a liquid injection without SPME in order to obtain optimized conditions for each of the 22 analytes investigated. Validation parameters were significantly influenced by both the injection mode (SPME vs liquid injection) and the temperature of SPME. Limits of quantification ranged from 0.05 pg mg(-1) for trifluralin to 10 pg mg(-1) for pentachlorophenol. The application of the validated method to the analysis of samples collected from non-occupationally exposed volunteers demonstrated the presence of pesticides in all the samples tested. Altogether, 13 different analytes were detected at concentration above the limit of quantification.

  11. On-line combination of high performance liquid chromatography with comprehensive two-dimensional gas chromatography-triple quadrupole mass spectrometry: a proof of principle study.

    Science.gov (United States)

    Zoccali, Mariosimone; Tranchida, Peter Quinto; Mondello, Luigi

    2015-02-03

    The present contribution is focused on the on-line combination of high performance liquid chromatography (HPLC), cryogenically modulated comprehensive two-dimensional gas chromatography (GC × GC), and triple quadrupole mass spectrometry (QqQ MS), generating a very powerful unified separation-science tool. The instrument can be used in seven different combinations ranging from one-dimensional HPLC with a photodiode array detector to on-line LC × GC × GC/QqQ MS. The main focus of the present research is directed to the LC-GC × GC/QqQ MS configuration, with its analytical potential shown in a proof-of-principle study involving a very complex sample, namely, coal tar. Specifically, a normal-phase LC process enabled the separation of three classes of coal tar compounds: (1) nonaromatic hydrocarbons; (2) unsaturated compounds (with and without S); (3) oxygenated constituents. The HPLC fractions were transferred to the GC × GC instrument via a syringe-based interface mounted on an autosampler. Each fraction was subjected to a specific programmed temperature vaporizer GC × GC/QqQ MS untargeted or targeted analysis. For example, the coal tar S-containing compounds were pinpointed through multiple-reaction-monitoring analysis, while full-scan information was attained for the oxygenated constituents.

  12. Application of enhanced gas chromatography/triple quadrupole mass spectrometry for monitoring petroleum weathering and forensic source fingerprinting in samples impacted by the Deepwater Horizon oil spill.

    Science.gov (United States)

    Adhikari, Puspa L; Wong, Roberto L; Overton, Edward B

    2017-10-01

    Accurate characterization of petroleum hydrocarbons in complex and weathered oil residues is analytically challenging. This is primarily due to chemical compositional complexity of both the oil residues and environmental matrices, and the lack of instrumental selectivity due to co-elution of interferences with the target analytes. To overcome these analytical selectivity issues, we used an enhanced resolution gas chromatography coupled with triple quadrupole mass spectrometry in Multiple Reaction Monitoring (MRM) mode (GC/MS/MS-MRM) to eliminate interferences within the ion chromatograms of target analytes found in environmental samples. This new GC/MS/MS-MRM method was developed and used for forensic fingerprinting of deep-water and marsh sediment samples containing oily residues from the Deepwater Horizon oil spill. The results showed that the GC/MS/MS-MRM method increases selectivity, eliminates interferences, and provides more accurate quantitation and characterization of trace levels of alkyl-PAHs and biomarker compounds, from weathered oil residues in complex sample matrices. The higher selectivity of the new method, even at low detection limits, provides greater insights on isomer and homolog compositional patterns and the extent of oil weathering under various environmental conditions. The method also provides flat chromatographic baselines for accurate and unambiguous calculation of petroleum forensic biomarker compound ratios. Thus, this GC/MS/MS-MRM method can be a reliable analytical strategy for more accurate and selective trace level analyses in petroleum forensic studies, and for tacking continuous weathering of oil residues. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Fingerprinting Deepwater Horizon Oil in the northern Gulf of Mexico using biomarkers and Gas Chromatography-Triple Quadrupole Mass Spectrometry (GC/MS/MS)

    Science.gov (United States)

    Adhikari, P. L.; Overton, E. B.; Maiti, K.; Wong, R. L.

    2016-02-01

    Petroleum biomarkers such as hopanes, steranes, and triaromatic steroids are more persistent than alkanes and aromatic compounds. Thus, they are often used to track spilled oil in the environments and as a proxy for weathering processes. The present study utilizes water samples, suspended and sinking particles, and seafloor sediments collected during 2011-2013 from various locations of the northern Gulf of Mexico with wide range of contaminated oil for Deepwater Horizon (DWH) oil fingerprinting. The MC252 source oil along with the samples collected in this study were analyzed using a gas chromatography coupled with a triple quadrupole mass spectrometry (GC/MS/MS) in Multiple Reaction Monitoring (MRM) mode and the results were compared with results from commonly used GC/MS selective ion monitoring (SIM) method. The results indicate that the MRM method separates interfering ions from interfering compounds and can be a powerful analytical strategy for a reliable identification and determination of trace levels of biomarkers in complex matrices. Source indicators such as the MRM fragment ion chromatograms of the biomarkers and their diagnostic ratios in samples were compared with the MC252 source oil. The preliminary results show that the biomarkers were below detection limits in dissolved samples. However, in few particulate and seafloor sediment samples, primarily from the immediate vicinity of the Macondo wellhead, contained their patterns. The results also illustrate that these biomarker compounds have been weathered within 1-3 years following the oil spill, and their DWH oil signature in some of these samples reflects this weathering.

  14. Intact Endogenous Metabolite Analysis of Mice Liver by Probe Electrospray Ionization/Triple Quadrupole Tandem Mass Spectrometry and Its Preliminary Application to in Vivo Real-Time Analysis.

    Science.gov (United States)

    Zaitsu, Kei; Hayashi, Yumi; Murata, Tasuku; Ohara, Tomomi; Nakagiri, Kenta; Kusano, Maiko; Nakajima, Hiroki; Nakajima, Tamie; Ishikawa, Tetsuya; Tsuchihashi, Hitoshi; Ishii, Akira

    2016-04-05

    Probe electrospray ionization (PESI) is a recently developed ionization technique that enables the direct detection of endogenous compounds like metabolites without sample preparation. In this study, we have demonstrated the first combination use of PESI with triple quadrupole tandem mass spectrometry (MS/MS), which was then applied to intact endogenous metabolite analysis of mice liver, achieving detection of 26 metabolites including amino acids, organic acids, and sugars. To investigate its practicality, metabolic profiles of control and CCl4-induced acute hepatic injury mouse model were measured by the developed method. Results showed clear separation of the two groups in score plots of principal component analysis and identified taurine as the primary contributor to group separation. The results were further validated by the established gas chromatography/MS/MS method, demonstrating the present method's usefulness. In addition, we preliminarily applied the method to real-time analysis of an intact liver of a living mouse. We successfully achieved monitoring of the real-time changes of two tricarboxylic acid cycle intermediates, α-ketoglutaric acid and fumaric acid, in the liver immediately after pyruvic acid injection via a cannulated tube to the portal vein. The present method achieved an intact analysis of metabolites in liver without sample preparation, and it also demonstrates future possibility to establish in vivo real-time metabolome analysis of living animals by PESI/MS/MS.

  15. Simultaneous determination of zearalenone and its derivatives in edible vegetable oil by gel permeation chromatography and gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Qian, Mingrong; Zhang, Hu; Wu, Liqin; Jin, Nuo; Wang, Jianmei; Jiang, Kezhi

    2015-01-01

    A sensitive gas chromatographic-triple quadrupole mass spectrometric (GC-QqQ MS) analytical method, for the determination of zearalenone and its five derivatives in edible vegetable oil, was developed. After the vegetable oil samples were prepared using gel permeation chromatography, the eluent was collected, evaporated and dried with nitrogen gas. The residue was silylated with N,O-bis-trimethylsilyltrifluoroacetamide, containing 1% trimethylchlorosilane. GC-QqQ MS was performed in the reaction-monitoring mode to confirm and quantify mycotoxins in vegetable oil. The limits of quantitation were 0.03-0.2 μg kg(-1) for the six mycotoxins. The average recoveries, measured at 2, 20 and 200 μg kg(-1), were in the range 80.3-96.5%. Zearalenone was detected in the range 5.2-184.6 μg kg(-1) in nine maize oils and at 40.7 μg kg(-1) in a rapeseed oil from the local market.

  16. Study of bis(bibenzyls) in bryophytes using electron ionization time-of-flight and electrospray ionization triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Guo, Huaifang; Xing, Jie; Xie, Chunfeng; Qu, Jianbo; Gao, Yanhui; Lou, Hongxiang

    2007-01-01

    A detailed analysis of mass spectra generated from bis(bibenzyl) compounds in bryophytes under electron ionization time-of-flight (EI-TOF) and electrospray ionization triple-quadrupole (ESI-TQ) mass spectrometry conditions is reported. Proposed structures of the fragment ions were obtained by tracking the functional groups of 15 bis(bibenzyls), the structures of which are similar except for some alkoxyl substituents and linkage sites of biphenyl ether bonds. The elucidation was aided by the use of accurate mass measurements. Attempts have been made to provide rational pathways for the formation of these fragment ions, and a generalized fragmentation mechanism is proposed. The bis(bibenzyls) mentioned in this study include three types according to their structure characteristics, i.e. one biphenyl ether bond (A-type), two biphenyl ether bonds (B-type), one biphenyl ether and one biphenyl bond (C-type). The three types display different EI-MS and ESI-MS/MS product profiles, by which the bis(bibenzyl) type and the number of alkoxyl substituents can be identified. Isomers of bis(bibenzyls) can be differentiated to some extent, while the linkage sites of biphenyl ether bonds are difficult to identify. The structure-fragmentation relationships will facilitate the characterization of other bis(bibenzyls) and this will be of value for the high-throughput screening of novel bis(bibenzyls) in bryophytes.

  17. Multistage fragmentation of ion trap mass spectrometry system and pseudo-MS3 of triple quadrupole mass spectrometry characterize certain (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones: a comparative study.

    Science.gov (United States)

    Abdelhameed, Ali S; Kadi, Adnan A; Abdel-Aziz, Hatem A; Angawi, Rihab F; Attwa, Mohamed W; Al-Rashood, Khalid A

    2014-01-01

    A new approach was recently introduced to improve the structure elucidation power of tandem mass spectrometry simulating the MS(3) of ion trap mass spectrometry system overcoming the different drawbacks of the latter. The fact that collision induced dissociation in the triple quadrupole mass spectrometer system provides richer fragment ions compared to those achieved in the ion trap mass spectrometer system utilizing resonance excitation. Moreover, extracting comprehensive spectra in the ion trap needs multistage fragmentation, whereas similar fragment ions may be acquired from one stage product ion scan using the triple quadrupole mass spectrometer. The new strategy was proven to enhance the qualitative performance of tandem mass spectrometry for structural elucidation of different chemical entities. In the current study we are endeavoring to prove our hypothesis of the efficiency of the new pseudo-MS(3) technique via its comparison with the MS(3) mode of ion trap mass spectrometry system. Ten pharmacologically and synthetically important (E)-3-(dimethylamino)-1-arylprop-2-en-1-ones (enaminones 4a-j) were chosen as model compounds for this study. This strategy permitted rigorous identification of all fragment ions using triple quadrupole mass spectrometer with sufficient specificity. It can be used to elucidate structures of different unknown components. The data presented in this paper provide clear evidence that our new pseudo-MS(3) may simulate the MS(3) of ion trap spectrometry system.

  18. Multistage Fragmentation of Ion Trap Mass Spectrometry System and Pseudo-MS3 of Triple Quadrupole Mass Spectrometry Characterize Certain (E-3-(Dimethylamino-1-arylprop-2-en-1-ones: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Ali S. Abdelhameed

    2014-01-01

    Full Text Available A new approach was recently introduced to improve the structure elucidation power of tandem mass spectrometry simulating the MS3 of ion trap mass spectrometry system overcoming the different drawbacks of the latter. The fact that collision induced dissociation in the triple quadrupole mass spectrometer system provides richer fragment ions compared to those achieved in the ion trap mass spectrometer system utilizing resonance excitation. Moreover, extracting comprehensive spectra in the ion trap needs multistage fragmentation, whereas similar fragment ions may be acquired from one stage product ion scan using the triple quadrupole mass spectrometer. The new strategy was proven to enhance the qualitative performance of tandem mass spectrometry for structural elucidation of different chemical entities. In the current study we are endeavoring to prove our hypothesis of the efficiency of the new pseudo-MS3 technique via its comparison with the MS3 mode of ion trap mass spectrometry system. Ten pharmacologically and synthetically important (E-3-(dimethylamino-1-arylprop-2-en-1-ones (enaminones 4a–j were chosen as model compounds for this study. This strategy permitted rigorous identification of all fragment ions using triple quadrupole mass spectrometer with sufficient specificity. It can be used to elucidate structures of different unknown components. The data presented in this paper provide clear evidence that our new pseudo-MS3 may simulate the MS3 of ion trap spectrometry system.

  19. Triple quadrupole tandem mass spectrometry: A real alternative to high resolution magnetic sector instrument for the analysis of polychlorinated dibenzo-p-dioxins, furans and dioxin-like polychlorinated biphenyls.

    Science.gov (United States)

    García-Bermejo, Ángel; Ábalos, Manuela; Sauló, Jordi; Abad, Esteban; González, María José; Gómara, Belén

    2015-08-19

    This paper reports on the optimisation, characterisation, validation and applicability of gas chromatography coupled to triple quadrupole mass spectrometry in its tandem operation mode (GC-QqQ(MS/MS) for the quantification of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs, dioxins) and dioxin-like polychlorinated biphenyls (DL-PCBs) in environmental and food matrices. MS/MS parameters were selected to achieve the high sensitivity and selectivity required for the analysis of this type of compounds and samples. Good repeatability for areas (RSD = 1-10%, for PCDD/Fs and DL-PCBs) and for ion transition ratios (RSD = 0.3-10%, for PCDD/Fs, and 0.2-15%, for DL-PCBs) and low instrumental limits of detection, 0.07-0.75 pg μL(-1) (for dioxins) and 0.05-0.63 pg μL(-1) (for DL-PCBs), were obtained. A comparative study of the congener specific determination using both GC-QqQ(MS/MS) and gas chromatography-high resolution mass spectrometry (GC-HRMS) was also performed by analysing several fortified samples and certified reference materials (CRMs) with low (feed and foodstuffs), median (sewage sludge) and high (fly ash) toxic equivalency (TEQ) concentration levels, i.e. 0.60, 1.83, 72.9 and 3609 pg WHO-TEQ(PCDD/Fs) g(-1). The agreement between the results obtained for the total TEQs (dioxins) on GC-QqQ(MS/MS) and GC-HRMS in all the investigated samples were within the range of ±4%, and that of DL-PCBs at concentration levels of 0.84 pg WHO-TEQs (DL-PCBs) g(-1), in the case of feedstuffs, was 0.11%. Both instrumental methods have similar and comparable linearity, precision and accuracy. The GC-QqQ(MS/MS) sensitivity, lower than that of GC-HRMS, is good enough (iLODs in the down to low pg levels) to detect the normal concentrations of these compounds in food and environmental samples. These results make GC-QqQ(MS/MS) suitable for the quantitative analysis of dioxins and DL-PCBs and a real alternative tool to the reference sector HRMS instruments. Copyright © 2015 Elsevier

  20. 三重四极杆质谱技术测定固体废弃物中多氯联苯%Determination of PCBs in Solid Waste by Triple Quadrupole Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    卢益; 郭志顺; 孙静; 朱明吉

    2012-01-01

    以二氯甲烷为萃取剂,采用快速溶剂萃取、凝胶渗透色谱净化、三重四极杆质谱技术测定固体废弃物中7种多氯联苯单体,选择十氯联苯为内标物,2,4,5,6 -四氯间二甲苯为替代物.质谱采用MRM扫描,优化了目标物质保留时间、母离子和子离子质量数及碰撞能量等参数.方法在0.050 mg/L ~2.00 mg/L范围内线性良好,7种多氯联苯单体的检出限为0.194 ng/g ~0.355 ng/g(以称取30 g样品、定容至2.0 mL计),标准样品回收率多在60% ~ 105%之间,空白加标样品测定值的相对标准偏差在8.6%~13.0%之间.%7 components of PCBs in solid waste were determined with triple quadrupole mass spectrometry by using accelerated solvent extraction and gel-permeation chromatograph purification. During the analysis process,methylene dichloride was used as extractant,decachlorobiphenyl as internal standard and 2,4,5,6 -Tetrachloro-m-xylene as surrogate. MRM was used as a quantitative scan mode. Experimental parameters were optimized for retention times of target compounds,mass numbers of parent ions and daughter ions and collision energy. The calibration curves of the method showed a good linearity from 0.050 mg/L to 2.00 mg/L,detection limits of 7 components of PCBs ranged form 0. 194 ng/g to 0. 355 ng/g ( 30 g sample,formulated into a volume 2.0 mL). Standard sample recoveries were between 60% and 105%. Relative standard deviations of spiked blank sample were between 8.6% and 13.0%.

  1. Preparation and characterization of amino functionalized nano-composite material and its application for multi-residue analysis of pesticides in cabbage by gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Zhao, Yong-Gang; Shen, Hao-Yu; Shi, Jia-Wei; Chen, Xiao-Hong; Jin, Mi-Cong

    2011-08-19

    In this paper, a novel and recyclable amino-functionalized nano-composite material (NCM) using tetraethylenepentamine (TEPA) as a coupling agent was synthesized. The properties of the TEPA-NCM were characterized by transmission electron microscopy (TEM), Fourier transform infrared analysis (FTIR), thermogravimetric analysis (TGA) and elemental analysis (EA). An effective dispersive solid-phase extraction (dSPE) procedure using the TEPA-NCM was developed, and comparative studies were carried out among Carbon/NH₂ SPE, primary secondary amine (PSA) dSPE and TEPA-NCM dSPE. The results showed that TEPA-NCM dSPE was faster, easier and more effective to clean and enrich than the Carbon/NH₂ cartridges, and the TEPA-NCM was much more effective to remove the pigments in vegetable samples than the PSA materials. The TEPA-NCM could be reused at least five times without much sacrifice of the cleanup efficiency. Furthermore, a gas chromatography-triple quadrupole mass spectrometry (GC-QqQ-MS/MS) method was established for the simultaneous determination of 29 pesticides (such as organochlorine and organophosphorus pesticides) in vegetables by dSPE using acetonitrile as an extraction solvent and TEPA-NCM as an adsorbent instead of PSA. The recoveries were in the range of 75-114% for all analytes except for trans-chlordane. The RSDs were in the range of 2-17%. The linearities were in the range of 0.4-100.0 μg/kg with determination coefficients (r²) higher than 0.986 for all compounds. The limits of detection (LODs) for all pesticides were less than 0.29 μg/kg and the limits of quantification (LOQs) were between 0.17 and 0.95 μg/kg. The developed method was applied to fifteen real vegetable samples, and it was confirmed that the TEPA-NCM was one of a kind of highly effective dSPE materials used for the pesticides analyses.

  2. Quantification of 2'-deoxy-2'-β-fluoro-4'-azidocytidine in rat and dog plasma using liquid chromatography-quadrupole time-of-flight and liquid chromatography-triple quadrupole mass spectrometry: Application to bioavailability and pharmacokinetic studies.

    Science.gov (United States)

    Peng, Youmei; Cheng, Tiefeng; Dong, Lihong; Zhang, Yuhai; Chen, Xiaojing; Jiang, Jinhua; Zhang, Jingmin; Guo, Xiaohe; Guo, Mintong; Chang, Junbiao; Wang, Qingduan

    2014-09-01

    2'-Deoxy-2'-β-fluoro-4'-azidocytidine (FNC) is a novel pyrimidine analog that inhibits not only the replication of the hepatitis B virus (HBV), hepatitis C virus (HCV) and HIV but also the replication of lamivudine-resistant HBV, 4'-azidocytidine or 2'-β-methylcytidine-resistant HCV, and nucleoside reverse-transcriptase inhibitor-resistant HIV variants. The present study was undertaken to evaluate the absolute oral bioavailability of FNC in rats and the pharmacokinetic properties of FNC after intragastric administration of single and multiple doses in rats and dogs. A sensitive high-performance liquid chromatography tandem quadrupole time-of-flight mass spectrometry (HPLC/Q-TOF MS) method and a reliable high-performance liquid chromatography tandem triple quadrupole mass spectrometry (HPLC/QqQ MS/MS) method were established for the determination of FNC in the rat and dog plasmas, respectively. The sample preparation involved a protein-precipitation method with methanol after the addition of lamivudine as an internal standard. FNC was analyzed by LC using a YMC-Pack Pro C18 column (150mm×4.6mm, 3μm) with methanol (containing 0.3% formic acid): 10mM ammonium acetate (containing 0.3% formic acid, pH 2.8) (35:65, v/v) as the mobile phase. Both mass spectrometers were equipped with an electrospray ionization interface in the positive-ion mode. The linear range was from 2.00 to 2000.00ngmL(-1) in rat plasma and 0.50 to 400.00ngmL(-1) in dog plasma. The intraday and interday precision were less than 10.55%, and the accuracy was in the range of -5.86 to 5.13%. The mean recoveries were greater than 82.70% and 82.97% for FNC and IS, respectively. The HPLC/Q-TOF MS and HPLC/QqQ MS/MS methods were both successfully applied in the pharmacokinetic studies of FNC in rats and dogs.

  3. A PRODUCT HYBRID GMRES ALGORITHM FOR NONSYMMETRIC LINEAR SYSTEMS

    Institute of Scientific and Technical Information of China (English)

    Bao-jiang Zhong

    2005-01-01

    It has been observed that the residual polynomials resulted from successive restarting cycles of GMRES(m) may differ from one another meaningfully. In this paper, it is further shown that the polynomials can complement one another harmoniously in reducing the iterative residual. This characterization of GMRES(m) is exploited to formulate an efficient hybrid iterative scheme, which can be widely applied to existing hybrid algorithms for solving large nonsymmetric systems of linear equations. In particular, a variant of the hybrid GMRES algorithm of Nachtigal, Reichel and Trefethen (1992) is presented. It is described how the new algorithm may offer significant performance improvements over the original one.

  4. Determination of eugenol in fish and shrimp muscle tissue by stable isotope dilution assay and solid-phase extraction coupled gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Li, Jincheng; Liu, Huan; Wang, Chaoying; Wu, Lidong; Liu, Dan

    2016-09-01

    In this study, we developed a new method for the accurate quantification of eugenol in fish samples based on stable isotope dilution assay (SIDA) and solid-phase extraction (SPE) coupled gas chromatography-triple quadrupole mass spectrometry (SIDA-SPE-GC-MS/MS). Due to the difference of matrix effect (ME), it was difficult to determine accurately the level of eugenol residue in different fish and shrimp samples based on external standard calibration method. SIDA was applied to compensate matrix effect (ME) that eugenol-d3 was used as internal standard (IS). Freshwater fish (carp, channel catfish), marine fish (turbot), and shrimp (Penaeus vannawei) were used for the method validation. The average recoveries of eugenol were in the range of 94.7 to 109.78 % when the spiking levels were 10, 50, and 200 μg kg(-1). The inter-day and intra-day precisions were in the range of 1.15-8.19 and 0.71-8.45 %. The limit of detection (LOD) and the limit of quantification (LOQ) were approximately 2.5 and 5.0 μg kg(-1). This method was applied to the real fish samples assay obtained from aquaculture markets in Beijing, China. Eugenol residue was found in two fish samples with the levels at 6.2 and 7.7 μg kg(-1), respectively. Graphical abstract Determination of eugenol in fish and shrimp muscle tissue.

  5. Determination of (236)U in environmental samples by single extraction chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2016-11-09

    In order to measure trace (236)U and (236)U/(238)U in environmental samples with a high matrix effect, a novel and simple method was developed that makes the digestion and purification procedures compatible with advanced triple-quadrupole inductively coupled plasma-mass spectrometry. A total dissolution of sample with HF + HNO3 + HClO4 was followed by chromatographic separation with a single resin column containing normal type DGA resin (N,N,N',N'-tetra-n-octyldiglycolamide) as the extractant system. The analytical accuracy and precision of (236)U/(238)U ratios, measured as (236)U(16)O(+)/(238)U(16)O(+), were examined by using the reference materials IAEA-135, IAEA-385, IAEA-447, and JSAC 0471. The low method detection limit (3.50 × 10(-6) Bq kg(-1)) makes it possible to perform routine monitoring of environmental (236)U due to global fallout combined with the Fukushima Daiichi Nuclear Power Plant accident fallout (>10(-5) Bq kg(-1)). Finally, the developed method was successfully applied to measure (236)U/(238)U ratios and (236)U activities in soil samples contaminated by the accident. The low (236)U/(238)U atom ratios ((1.50-13.5) × 10(-8)) and (236)U activities ((2.25-14.1) × 10(-2) mBq kg(-1)) indicate (236)U contamination was mainly derived from global fallout in the examined samples.

  6. Comparison of a triple-quadrupole and a quadrupole time-of-flight mass analyzer to quantify 16 opioids in human plasma.

    Science.gov (United States)

    Viaene, Johan; Lanckmans, Katrien; Dejaegher, Bieke; Mangelings, Debby; Vander Heyden, Yvan

    2016-08-05

    The aim of this work is to study whether a quadrupole time-of-flight (QToF) mass analyzer, coupled to an ultra high performance liquid chromatography (UHPLC) system, can be a valuable alternative for a triple-quadrupole (QqQ) mass analyzer, for quantitative toxicological purposes. The case study considered was the quantification of 16 opioids (6-monoacetylmorphine, buprenorphine, codeine, dihydrocodeine, ethylmorphine, fentanyl, hydrocodone, hydromorphone, morphine, norbuprenorphine, norcodeine, norfentanyl, oxycodone, oxymorphone, pholcodine and tilidine) in human plasma. Both methods were validated in parallel in terms of selectivity, matrix effects, extraction recovery, carry-over, bias, precision and sensitivity. Accuracy-profile methodology was used to determine the optimal calibration model, and to estimate bias, repeatability, intermediate precision and total error. Selectivity was demonstrated for all opioids and deuterated analogues, except for codeine-d3 on the UHPLC-QTOF. For most compounds, extraction recoveries were in the range 60 to 80% on both systems, except for the synthetic analogues, buprenorphine, fentanyl and tilidine, where large variability is observed. Carry-over was negligible on both systems. For different opioids, the optimal calibration model was different between the systems. The accuracy profiles of the majority of the opioids indicated that, over the entire tested concentration range, for more than 5% of the future measurements, total errors are expected to exceed the a priori defined 15% acceptance limit. For some exceptions, however, the measurements even suffer from total errors above 30%, which can be attributed to the solid phase extraction procedure that was applied as sample pretreatment technique. Sensitivity was generally tenfold better on the LC-QToF system, probably due to the difference in ion choice for quantification between both systems. In conclusion, the best performing system seemed to depend on the compound, on the

  7. Confirmatory analysis of sulfonamide antibacterials in bovine liver and kidney: extraction with hot water and liquid chromatography coupled to a single- or triple-quadrupole mass spectrometer.

    Science.gov (United States)

    Bogialli, Sara; Curini, Roberta; Di Corcia, Antonio; Nazzari, Manuela; Sergi, Manuel

    2003-01-01

    A simple, specific, and rapid confirmatory method for determining 12 sulfonamide (SAs) antibacterials in bovine liver and kidney is presented. This method is based on the matrix solid-phase dispersion technique with hot water as extractant followed by liquid chromatography/mass spectrometry (LC/MS) with an electrospray ion source. The method was tailored for use with both single-quadrupole MS (I) and triple-quadrupole MS (II) instruments. After acidification and filtration of the aqueous extract, a 250-microL aliquot was injected into instrument I while only 25 microL was analyzed by instrument II. With instrument I MS data acquisition was performed in the selected ion monitoring (SIM) mode, selecting at least three ions for each target compound. With instrument II the selected reaction monitoring (SRM) mode with three fragmentation reactions for each compound was chosen. With the exception of sulfaquinoxaline (SQX), recovery of the analytes at the 50 ppb level in both liver and kidney was 72-96% with relative standard deviations (RSDs) ranging between 3 and 11%. The very poor recovery of SQX was due to its rapid enzymatic oxidation when in contact with the two tissues. With instrument I, limits of quantification (LOQs, S/N = 10) were 5-14 ppb of SAs. Even lower LOQs (1-8 ppb) were estimated by using instrument II, even though the extract volume analyzed was ten times lower than that with instrument I. With both matrices and using instrument I, severe ion signal suppression was experienced for the early-eluted SAs when trying to fractionate analytes by using a short chromatographic run time. This effect was traced to polar endogenous co-extractives eluted in the first part of the chromatographic run that interfered with gas-phase ion formation for SAs. Adopting more selective chromatographic conditions minimized this effect.

  8. Monitoring quinolone antibacterial residues in bovine tissues: extraction with hot water and liquid chromatography coupled to a single- or triple-quadrupole mass spectrometer.

    Science.gov (United States)

    Bogialli, Sara; D'Ascenzo, Giuseppe; Di Corcia, Antonio; Innocenti, Giorgiana; Laganà, Aldo; Pacchiarotta, Tiziana

    2007-01-01

    A rapid and sensitive procedure for determining residues of seven quinolone antibacterials in bovine muscle, kidney and liver is presented. The method is based on the matrix solid-phase dispersion (MSPD) technique with hot water as extractant followed by liquid chromatography/single quadrupole mass spectrometry (LC/MS) or triple-quadrupole mass spectrometry (LC/MS/MS). After dispersing tissue samples on hydrazine sulfate treated sand, target compounds were eluted from the MSPD column by passing through it 4 mL of water heated at 100 degrees C. After pH adjustment and filtration, 200 and 5 microL of the aqueous extracts were respectively injected into the LC/MS and LC/MS/MS instruments. With the former instrument, MS data were acquired in the three-ion selected ion monitoring mode, while MS/MS data acquisition was performed in the multi-reaction monitoring mode by selecting two precursor ion to product ion transitions for each target compound. Hot water appeared to be an efficient extracting medium, since absolute recoveries of the analytes were 84-102%. Using norfloxacin (a quinolone not used in veterinary medicine) as surrogate internal standard, the accuracy of the method at three concentration levels equal to 0.5, 1 and 1.5 times the maximum residue limits (MRLs) set by the european union was 88-109% with relative standard deviations (RSDs) not higher than 7%. The use of LC/MS/MS allowed detection and quantification of the analytes in any tissue considered to be performed at concentrations by far lower than half of their MRLs. Vice versa, the single-quadrupole MS arrangement, while succeeding in monitoring quinolones in muscle tissue at the 0.5 MRL level, showed to be not sufficiently selective for unambiguous identification of some quinolones in kidney and liver.

  9. Determination of volatile organic compounds in water by headspace solid-phase microextraction gas chromatography coupled to tandem mass spectrometry with triple quadrupole analyzer.

    Science.gov (United States)

    Cervera, M I; Beltran, J; Lopez, F J; Hernandez, F

    2011-10-17

    In the present work, a rapid method with little sample handling has been developed for determination of 23 selected volatile organic compounds in environmental and wastewater samples. The method is based on headspace solid-phase microextraction (SPME) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) determination using triple quadrupole analyzer (QqQ) in electron ionization mode. The best conditions for extraction were optimised with a factorial design taking into account the interaction between different parameters and not only individual effects of variables. In the optimized procedure, 4 mL of water sample were extracted using a 10 mL vial and adding 0.4 g NaCl (final NaCl content of 10%). An SPME extraction with carboxen/polydimethylsiloxane 75 μm fiber for 30 min at 50°C (with 5 min of previous equilibration time) with magnetic stirring was applied. Chromatographic determination was carried out by GC-MS/MS working in Selected Reaction Monitoring (SRM) mode. For most analytes, two MS/MS transitions were acquired, although for a few compounds it was difficult to obtain characteristic abundant fragments. In those cases, a pseudo selected reaction monitoring (pseudo-SRM) with three ions was used instead. The intensity ratio between quantitation (Q) and confirmation (q) signals was used as a confirmatory parameter. The method was validated by means of recovery experiments (n=6) spiking mineral water samples at three concentration levels (0.1, 5 and 50 μg L(-1)). Recoveries between 70% and 120% were generally obtained with relative standard deviations (RSDs) lower than 20%. The developed method was applied to surface water and wastewater from a wastewater treatment plant and from a municipal solid-waste treatment plant. Several compounds, like chloroform, benzene, trichloroethylene, toluene, tetrachloroethylene, dibromochloromethane, xylenes and bromoform were detected and confirmed in all the samples analyzed.

  10. Instrument contributions to resolution and sensitivity in ultra high performance liquid chromatography using small bore columns: comparison of diode array and triple quadrupole mass spectrometry detection.

    Science.gov (United States)

    Buckenmaier, Stephan; Miller, Christine A; van de Goor, Tom; Dittmann, Monika M

    2015-01-16

    UHPLC with DAD-UV detection or in combination with mass spectrometry (MS) has proven to be a robust and widely applicable platform for high sensitivity analyses of many types of chemical compounds. The majority of users employ narrow bore columns with 2.1mm internal diameter (ID) typically exhibiting very high efficiencies (>200,000 plates/m). This ultimately sets stringent demands upon the chromatographic system as the separation efficiency can be compromised by external contributions to dispersion caused by connection capillaries, auto-sampler and/or the detection device. Sample limited applications often use reduced column diameters down to capillary- or even nano-column format. Capillary (ID≤0.5mm) or small-bore columns (ID≤1mm) can be a good compromise between system robustness and enhanced sensitivity. Yet in this case, extra-column dispersion gains additional importance due to reduced peak volumes. To design an optimized system configuration for specific column dimensions and applications it is crucial to understand the dispersion contributions of individual extra-column components. This was subject to many studies done within our group and by others. Here, we employed a fully optimized UHPLC/UV system to investigate the contribution to peak dispersion obtained from columns ranging from capillary to narrow bore (0.3, 0.5, 1, 2.1mm) using a set of small molecules that were analyzed in gradient mode. Further UV detection was replaced by a triple quadrupole (QQQ) MS in order to evaluate its contribution to band broadening. In this context the impact of column-ID upon MS sensitivity when interfaced with an Agilent Jet Stream source was investigated. Data obtained from our test suite of compounds shows mostly mass-sensitive behavior of this advanced electrospray technology.

  11. Efficient tandem solid-phase extraction and liquid chromatography-triple quadrupole mass spectrometry method to determine polar benzotriazole, benzothiazole and benzenesulfonamide contaminants in environmental water samples.

    Science.gov (United States)

    Herrero, P; Borrull, F; Pocurull, E; Marcé, R M

    2013-09-27

    An analytical method has been developed that allows the simultaneous determination of five benzotriazole (BTRs), four benzothiazole (BTs) and five benzenesulfonamide (BSAs) derivates. The method is based on tandem solid-phase extraction (SPE) with Oasis HLB followed by a clean-up step with Florisil. The chromatographic analysis was performed in less than 15min and detection was carried out with a triple quadrupole mass analyser operating in multiple reaction monitoring (MRM) mode. A comparison was performed between Oasis HLB and Oasis MAX sorbents for the solid-phase extraction, with Oasis HLB being the sorbent that gave the highest recoveries, ranging between 75% and 106%, depending on the compound and the matrix analysed. The proposed clean-up with Florisil sorbent reduced the matrix effect to below 20%. The repeatability (%RSD, 50-3000ng/L, n=3) of the method was less than 15% for all of the compounds in all of the matrices. The limits of detection (LODs) achieved ranged from 1ng/L for BTR in river water up to 100ng/L for BT in influent sewage. All of the compounds were determined in environmental waters such as river water and sewage. The highest concentrations determined corresponded to influent sewage samples in which the sum of concentrations for all compounds were between 4.6μg/L and 8.0μg/L. These concentrations were slightly reduced in secondary effluent and tertiary effluent sewage. Moreover, samples from tertiary effluent sewage based on ultra-filtration membrane treatments were also analysed and preliminary results seem to indicate that these treatments may be most effective for removing BTR, BT and BSA derivates.

  12. Quantitation of isobaric phosphatidylcholine species in human plasma using a hybrid quadrupole linear ion-trap mass spectrometer.

    Science.gov (United States)

    Zacek, Petr; Bukowski, Michael; Rosenberger, Thad A; Picklo, Matthew

    2016-12-01

    Phosphatidylcholine (PC) species in human plasma are used as biomarkers of disease. PC biomarkers are often limited by the inability to separate isobaric PCs. In this work, we developed a targeted shotgun approach for analysis of isobaric and isomeric PCs. This approach is comprised of two MS methods: a precursor ion scanning (PIS) of mass m/z 184 in positive mode (PIS m/z +184) and MS(3) fragmentation in negative mode, both performed on the same instrument, a hybrid triple quadrupole ion-trap mass spectrometer. The MS(3) experiment identified the FA composition and the relative abundance of isobaric and sn-1, sn-2 positional isomeric PC species, which were subsequently combined with absolute quantitative data obtained by PIS m/z +184 scan. This approach was applied to the analysis of a National Institute of Standards and Technology human blood plasma standard reference material (SRM 1950). We quantified more than 70 PCs and confirmed that a majority are present in isobaric and isomeric mixtures. The FA content determined by this method was comparable to that obtained using GC with flame ionization detection, supporting the quantitative nature of this MS method. This methodology will provide more in-depth biomarker information for clinical and mechanistic studies.

  13. Total 25-Hydroxyvitamin D Determination by an Entry Level Triple Quadrupole Instrument: Comparison between Two Commercial Kits

    Directory of Open Access Journals (Sweden)

    Jacopo Gervasoni

    2013-01-01

    Full Text Available Objective. 25-hydroxyvitamin D2/D3 (25-OHD2/D3 determination is a reliable biomarker for vitamin D status. Liquid chromatography-tandem mass spectrometry was recently proposed as a reference method for vitamin D status evaluation. The aim of this work is to compare two commercial kits (Chromsystems and PerkinElmer for 25-OHD2/D3 determination by our entry level LC-MS/MS. Design and Methods. Chromsystems kit adds an online trap column to an HPLC column and provides atmospheric pressure chemical ionization, isotopically labeled internal standard, and 4 calibrator points. PerkinElmer kit uses a solvent extraction and protein precipitation method. This kit can be used with or without derivatization with, respectively, electrospray and atmospheric pressure chemical ionization. For each analyte, there are isotopically labeled internal standards and 7 deuterated calibrator points. Results. Performance characteristics are acceptable for both methods. Mean bias between methods calculated on 70 samples was 1.9 ng/mL. Linear regression analysis gave an of 0.94. 25-OHD2 is detectable only with PerkinElmer kit in derivatized assay option. Conclusion. Both methods are suitable for routine. Chromsystems kit minimizes manual sample preparation, requiring only protein precipitation, but, with our system, 25-OHD2 is not detectable. PerkinElmer kit without derivatization does not guarantee acceptable performance with our LC-MS/MS system, as sample is not purified online. Derivatization provides sufficient sensitivity for 25-OHD2 detection.

  14. Metabolite Profile of Salidroside in Rats by Ultraperformance Liquid Chromatography Coupled with Quadrupole Time-of-Flight Mass Spectrometry and High-Performance Liquid Chromatography Coupled with Quadrupole-Linear Ion Trap Mass Spectrometry.

    Science.gov (United States)

    Hu, Zhiwei; Wang, Ziming; Liu, Yong; Wu, Yan; Han, Xuejiao; Zheng, Jian; Yan, Xiufeng; Wang, Yang

    2015-10-21

    In the present work, the salidroside metabolite profile in rat urine was investigated, and subsequently the metabolic pathways of salidroside were proposed. After administrations of salidroside at an oral dose of 100 or 500 mg/kg, rat urine samples were collected and pretreated with methanol to precipitate the proteins. The pretreated samples were analyzed by an Acquity ultraperformance liquid chromatography (UPLC) coupled with an HSS T3 column and detected by quadrupole time-of-flight mass spectrometry (Q-TOF-MS) or high-performance liquid chromatography coupled with hybrid triple-quadrupole linear ion trap mass spectrometry (HPLC/Q-trap-MS). A total of eight metabolites were detected and identified on the basis of the characteristics of their protonated ions in the urine samples. The results elucidated that salidroside was metabolized via glucuronidation, sulfation, deglycosylation, hydroxylation, methylation, and dehydroxylation pathways in vivo.

  15. Simultaneous Analysis of 3-MCPD and 1,3-DCP in Asian Style Sauces Using QuEChERS Extraction and Gas Chromatography–Triple Quadrupole Mass Spectrometry

    Science.gov (United States)

    Genualdi, Susan; Nyman, Patricia; DeJager, Lowri

    2017-01-01

    Acid hydrolyzed vegetable protein (aHVP) is used for flavoring a wide variety of foods and also in the production of nonfermented soy sauce. During the production of aHVP, chloropropanols including 3-monochloropropane-1,2-diol (3-MCPD) and 1,3 dichloropropane-2-ol (1,3-DCP) can be formed through the reaction of the hydrochloric acid catalyst and residual fat and the reaction of 3-MCPD with acetic acid, respectively. 3-MCPD is a carcinogen, and 1,3-DCP has been classified as a genotoxic carcinogen. The European Union (EU) has set a maximum concentration of 0.02 mg/kg of 3-MCPD in aHVP, and the Food and Drug Administration (FDA) set a guidance limit of 1 mg/kg of 3-MCPD in aHVP. 1,3-DCP is not an approved food additive, and the Joint FAO/WHO Expert Committee on Food Additives (JEFCA) has set a limit at 0.005 mg/kg, which is close to the estimated method detection limit. Currently there are few analytical methods for the simultaneous determination of 3-MCPD and 1,3-DCP without derivatization due to differences in their physical chemical properties and reactivity. A new method was developed using QuEChERS (quick, easy, cheap, effective, rugged, and safe) with direct analysis of the extract without derivatization using gas chromatography–triple quadrupole mass spectrometry (GC-QQQ). Additionally, a market sampling of 60 soy sauce samples was performed in 2015 to determine if concentrations have changed since the FDA limit was set in 2008. The sampling results were compared between the new QuEChERS method and a method using phenylboronic acid (PBA) as a derivatizing agent for 3-MCPD analysis. The concentrations of 3-MCPD detected in soy sauce samples collected in 2015 (

  16. Characterization of TATP gas phase product ion chemistry via isotope labeling experiments using ion mobility spectrometry interfaced with a triple quadrupole mass spectrometer.

    Science.gov (United States)

    Tomlinson-Phillips, Jill; Wooten, Alfred; Kozole, Joseph; Deline, James; Beresford, Pamela; Stairs, Jason

    2014-09-01

    Identification of the fragment ion species associated with the ion reaction mechanism of triacetone triperoxide (TATP), a homemade peroxide-based explosive, is presented. Ion mobility spectrometry (IMS) has proven to be a key analytical technique in the detection of trace explosive material. Unfortunately, IMS alone does not provide chemical identification of the ions detected; therefore, it is unknown what ion species are actually formed and separated by the IMS. In IMS, ions are primarily characterized by their drift time, which is dependent on the ion׳s mass and molecular cross-section; thus, IMS as a standalone technique does not provide structural signatures, which is in sharp contrast to the chemical and molecular information that is generally obtained from other customary analytical techniques, such as NMR, Raman and IR spectroscopy and mass spectrometry. To help study the ion chemistry that gives rise to the peaks observed in IMS, the hardware of two different commercial IMS instruments has been directly coupled to triple quadrupole (QQQ) mass spectrometers, in order to ascertain each ion׳s corresponding mass/charge (m/z) ratios with different dopants at two temperatures. Isotope labeling was then used to help identify and confirm the molecular identity of the explosive fragment and adduct ions of TATP. The m/z values and isotope labeling experiments were used to help propose probable molecular formulas for the ion fragments. In this report, the fragment and adduct ions m/z 58 and 240 of TATP have been confirmed to be [C3H6NH·H](+) and [TATP·NH4](+), respectively; while the fragment ions m/z 73 and 89 of TATP are identified as having the molecular formulas [C4H9NH2](+) and [C4H9O2](+), respectively. It is anticipated that the work in this area will not only help to facilitate improvements in mobility-based detection (IMS and MS), but also aid in the development and optimization of MS-based detection algorithms for TATP.

  17. Determination of volatile organic compounds in water by headspace solid-phase microextraction gas chromatography coupled to tandem mass spectrometry with triple quadrupole analyzer

    Energy Technology Data Exchange (ETDEWEB)

    Cervera, M.I. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain); Beltran, J., E-mail: joaquim.beltran@uji.es [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain); Lopez, F.J.; Hernandez, F. [Research Institute for Pesticides and Water, University Jaume I, Avda. Sos Baynat, E-12071 Castellon (Spain)

    2011-10-17

    Highlights: {yields} Employing a statistical optimization improves results reducing experiments. {yields} Use of MS (QqQ) allows high sensitivity determination and improves identification capabilities. {yields} Using Q/q intensity ratios is a powerful tool to ensure compound identification. {yields} HS SPME GC-MS/MS method allows determination of VOCs in complex matrix water samples. - Abstract: In the present work, a rapid method with little sample handling has been developed for determination of 23 selected volatile organic compounds in environmental and wastewater samples. The method is based on headspace solid-phase microextraction (SPME) followed by gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) determination using triple quadrupole analyzer (QqQ) in electron ionization mode. The best conditions for extraction were optimised with a factorial design taking into account the interaction between different parameters and not only individual effects of variables. In the optimized procedure, 4 mL of water sample were extracted using a 10 mL vial and adding 0.4 g NaCl (final NaCl content of 10%). An SPME extraction with carboxen/polydimethylsiloxane 75 {mu}m fiber for 30 min at 50 deg. C (with 5 min of previous equilibration time) with magnetic stirring was applied. Chromatographic determination was carried out by GC-MS/MS working in Selected Reaction Monitoring (SRM) mode. For most analytes, two MS/MS transitions were acquired, although for a few compounds it was difficult to obtain characteristic abundant fragments. In those cases, a pseudo selected reaction monitoring (pseudo-SRM) with three ions was used instead. The intensity ratio between quantitation (Q) and confirmation (q) signals was used as a confirmatory parameter. The method was validated by means of recovery experiments (n = 6) spiking mineral water samples at three concentration levels (0.1, 5 and 50 {mu}g L{sup -1}). Recoveries between 70% and 120% were generally obtained with

  18. Quantification of tamoxifen and three of its phase-I metabolites in human plasma by liquid chromatography/triple-quadrupole mass spectrometry.

    Science.gov (United States)

    Binkhorst, Lisette; Mathijssen, Ron H J; Ghobadi Moghaddam-Helmantel, Inge M; de Bruijn, Peter; van Gelder, Teun; Wiemer, Erik A C; Loos, Walter J

    2011-12-15

    In view of future pharmacokinetic studies, a highly sensitive ultra performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS) method has been developed for the simultaneous quantification of tamoxifen and three of its main phase I metabolites in human lithium heparinized plasma. The analytical method has been thoroughly validated in agreement with FDA recommendations. Plasma samples of 200 μl were purified by liquid-liquid extraction with 1 ml n-hexane/isopropanol, after deproteination through addition of 50 μl acetone and 50 μl deuterated internal standards in acetonitrile. Tamoxifen, N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen and endoxifen were chromatographically separated on an Acquity UPLC(®) BEH C18 1.7 μm 2.1 mm×100 mm column eluted at a flow-rate of 0.300 ml/min on a gradient of 0.2mM ammonium formate and acetonitrile, both acidified with 0.1% formic acid. The overall run time of the method was 10 min, with elution times of 2.9, 3.0, 4.1 and 4.2 min for endoxifen, 4-hydroxy-tamoxifen, N-desmethyl-tamoxifen and tamoxifen, respectively. Tamoxifen and its metabolites were quantified by triple-quadrupole mass spectrometry in the positive ion electrospray ionization mode. The multiple reaction monitoring transitions were set at 372>72 (m/z) for tamoxifen, 358>58 (m/z) for N-desmethyl-tamoxifen, 388>72 (m/z) for 4-hydroxy-tamoxifen and 374>58 (m/z) for endoxifen. The analytical method was highly sensitive with the lower limit of quantification validated at 5.00 nM for tamoxifen and N-desmethyl-tamoxifen and 0.500 nM for 4-hydroxy-tamoxifen and endoxifen, which is equivalent to 1.86, 1.78, 0.194 and 0.187 ng/ml for tamoxifen, N-desmethyl-tamoxifen, 4-hydroxy-tamoxifen and endoxifen, respectively. The method was also precise and accurate, with within-run and between-run precisions within 12.0% and accuracy ranging from 89.5 to 105.3%. The method has been applied to samples from a clinical study and cross-validated with a validated LC

  19. Utilization of MATLAB in Simulation of Linear Hybrid Circuits

    OpenAIRE

    BRANCIK, L.

    2003-01-01

    In the paper a MATLAB-based method for simulating transient phenomena in linear hybrid circuits containing parts with both lumped and distributed parameters is presented. Distributed parts of the circuit are multiconductor transmission lines, which can generally be nonuniform, with frequency-dependent parameters, and under nonzero initial voltage and/or current distributions. In principle a solution is formulated using the modified nodal analysis method in the frequency domain. Subsequently a...

  20. Quantification of urinary o,o'-dityrosine, a biomarker for oxidative damage to proteins, by high performance liquid chromatography with triple quadrupole tandem mass spectrometry. A comparison with ion-trap tandem mass spectrometry.

    Science.gov (United States)

    Orhan, Hilmi; Coolen, Stefan; Meerman, John H N

    2005-11-15

    We recently described an isotope dilution reversed-phase liquid chromatography-atmospheric pressure chemical ionization-ion-trap-tandem mass spectrometry (HPLC-APCI-MS/MS) method for the quantitative determination of oxidized amino acids in human urine, including o,o'-dityrosine, a specific marker of protein oxidation. In the present study, we investigated the possibility to use a triple quadrupole instrument for the analysis of this biomarker in urine. The two instruments were compared in terms of sensitivity, specificity and reproducibility. Results showed that the triple quadrupole instrument reaches 2.5-fold higher sensitivity (LOD=0.01 microM) compared to the previously used ion-trap instrument. Precision of the present assay is as follows: in-day variation is 4.6% and inter-day variation is 17%. The currently developed method was applied to a group of smoker urine samples. The mean urinary o,o'-dityrosine concentration was 0.08+/-0.01 microM. Expressed per urinary creatinine concentration, this corresponds to 10.1+/-0.4 micromol/mol creatinine. This is comparable to the previously reported values of 5.8+/-0.3 micromol/mol creatinine in non-smokers night-time urines, and 12.3+/-5 micromol/mol creatinine in day-time urines measured by the ion-trap instrument.

  1. Hybrid Spectral Unmixing: Using Artificial Neural Networks for Linear/Non-Linear Switching

    Directory of Open Access Journals (Sweden)

    Asmau M. Ahmed

    2017-07-01

    Full Text Available Spectral unmixing is a key process in identifying spectral signature of materials and quantifying their spatial distribution over an image. The linear model is expected to provide acceptable results when two assumptions are satisfied: (1 The mixing process should occur at macroscopic level and (2 Photons must interact with single material before reaching the sensor. However, these assumptions do not always hold and more complex nonlinear models are required. This study proposes a new hybrid method for switching between linear and nonlinear spectral unmixing of hyperspectral data based on artificial neural networks. The neural networks was trained with parameters within a window of the pixel under consideration. These parameters are computed to represent the diversity of the neighboring pixels and are based on the Spectral Angular Distance, Covariance and a non linearity parameter. The endmembers were extracted using Vertex Component Analysis while the abundances were estimated using the method identified by the neural networks (Vertex Component Analysis, Fully Constraint Least Square Method, Polynomial Post Nonlinear Mixing Model or Generalized Bilinear Model. Results show that the hybrid method performs better than each of the individual techniques with high overall accuracy, while the abundance estimation error is significantly lower than that obtained using the individual methods. Experiments on both synthetic dataset and real hyperspectral images demonstrated that the proposed hybrid switch method is efficient for solving spectral unmixing of hyperspectral images as compared to individual algorithms.

  2. Hybrid proper orthogonal decomposition formulation for linear structural dynamics

    Science.gov (United States)

    Placzek, A.; Tran, D.-M.; Ohayon, R.

    2008-12-01

    Hybrid proper orthogonal decomposition (PODh) formulation is a POD-based reduced-order modeling method where the continuous equation of the physical system is projected on the POD modes obtained from a discrete model of the system. The aim of this paper is to evaluate the hybrid POD formulation and to compare it with other POD formulations on the simple case of a linear elastic rod subject to prescribed displacements in the perspective of building reduced-order models for coupled fluid-structure systems in the future. In the first part of the paper, the hybrid POD is compared to two other formulations for the response to an initial condition: an approach based on the discrete finite elements equation of the rod called the discrete POD (PODd), and an analytical approach using the exact solution of the problem and consequently called the analytical POD (PODa). This first step is useful to ensure that the PODh performs well with respect to the other formulations. The PODh is therefore used afterwards for the forced motion response where a displacement is imposed at the free end of the rod. The main contribution of this paper lies in the comparison of three techniques used to take into account the non-homogeneous Dirichlet boundary condition with the hybrid POD: the first method relies on control functions, the second on the penalty method and the third on Lagrange multipliers. Finally, the robustness of the hybrid POD is investigated on two examples involving firstly the introduction of structural damping and secondly a nonlinear force applied at the free end of the rod.

  3. Utilization of MATLAB in Simulation of Linear Hybrid Circuits

    Directory of Open Access Journals (Sweden)

    L. Brancik

    2003-12-01

    Full Text Available In the paper a MATLAB-based method for simulating transientphenomena in linear hybrid circuits containing parts with both lumpedand distributed parameters is presented. Distributed parts of thecircuit are multiconductor transmission lines, which can generally benonuniform, with frequency-dependent parameters, and under nonzeroinitial voltage and/or current distributions. In principle a solutionis formulated using the modified nodal analysis method in the frequencydomain. Subsequently an improved fast method of the numerical inversionof Laplace transforms in the vector or matrix form is applied to obtainsolution in the time domain.

  4. Star-Shaped and Linear POSS-Polylactide Hybrid Copolymers

    Directory of Open Access Journals (Sweden)

    Krystyna Rozga-Wijas

    2015-07-01

    Full Text Available Novel octakis-2[(6-hydroxyhexylthio]ethyl-octasilsesquioxane (POSS-S-OH as well as heptaisobutyl-2[(6-hydroxyhexylthio]ethyl-octasilsesquioxane (iBu-POSS-S-OH were synthesized. POSS structures, bearing both types of groups i.e., 2[(6-hydroxyhexylthio]ethyl and the vinyl ones, pendant from the octahedral cage are also described. The synthetic pathway involved thiol-ene click reaction of 6-mercapto-1-hexanol (MCH to octavinyloctasilsesquioxane (POSS-Vi, and heptaisobutylvinyloctasilsesquioxane (iBu-POSS-Vi, in the presence of 2,2′-azobisisobutyronitrile. The functionalized silsesquioxane cages of regular octahedral structure were used further as initiators for ring opening polymerization of L,L-dilactide, catalyzed by tin (II 2-ethylhexanoate. The polymerization afforded biodegradable hybrid star shape and linear systems with an octasilsesquioxane cage as a core, bearing polylactide arm(s.

  5. Linear engine development for series hybrid electric vehicles

    Science.gov (United States)

    Toth-Nagy, Csaba

    This dissertation argues that diminishing oil reserves, concern over global climate change, and desire to improve ambient air quality all demand the development of environment-friendly personal transportation. In certain applications, series hybrid electric vehicles offer an attractive solution to reducing fuel consumption and emissions. Furthermore, linear engines are emerging as a powerplant suited to series HEV applications. In this dissertation, a linear engine/alternator was considered as the auxiliary power unit of a range extender series hybrid electric vehicle. A prototype linear engine/alternator was developed, constructed and tested at West Virginia University. The engine was a 2-stroke, 2-cylinder, dual piston, direct injection, diesel engine. Experiment on the engine was performed to study its behavior. The study variables included mass of the translator, amount of fuel injected, injection timing, load, and stroke with operating frequency and mechanical efficiency as the basis of comparison. The linear engine was analyzed in detail and a simple simulation model was constructed to compare the trends of simulation with the experimental data and to expand on the area where the experimental data were lacking. The simulation was based on a simple and analytical model, rather than a detailed and intensely numerical one. The experimental and theoretical data showed similar trends. Increasing translator mass decreased the operating frequency and increased compression ratio. Larger mass and increased compression ratio improved the ability of the engine to sustain operation and the engine was able to idle on less fuel injected into the cylinder. Increasing the stroke length caused the operating frequency to drop. Increasing fueling or decreasing the load resulted in increased operating frequency. This projects the possibility of using the operating frequency as an input for feedback control of the engine. Injection timing was varied to investigate two different

  6. 气相色谱-串联质谱法测定水中痕量有机磷农药和甲萘威%Determination of Organophosphorus Pesticides and Carbaryl in Environmental Water by Gas Chromatography with Triple Quadrupole Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    施择; 黄云; 张榆霞; 赵安楠; 金玉; 铁程

    2014-01-01

    A method of gas chromatography coupled with triple quadrupole mass spectrometry was estab-lished for determining organophosphorus pesticides and carbaryl in water.The experimental results showed that all the target compounds had good linear relations in the range of 20.0 μg/L~1 000 μg/L.The method limits of detection were 0.004 μg/L~0.01 μg/L.The recoveries of the target compounds ranged from 71.8% to 94.5%and the RSDs were between 3.7% ~8.5% for three concentrations of 0.02 μg/L,0.05 μg/L and 0.1 μg/L. The method could meet the requirements for determination of trace organophosphorus pesticide and carbaryl in water samples.%采用二氯甲烷萃取水样,气相色谱-串联质谱法同时测定水中有机磷农药和甲萘威。试验表明:方法在20.0μg/L ~1000μg/L范围内,各目标化合物线性良好;方法检出限为0.004μg/L~0.01μg/L;对实际水样进行3个质量浓度水平的加标回收试验,回收率在71.8%~94.5%之间,RSD为3.7%~8.5%,满足水中痕量有机磷农药和甲萘威的测定要求。

  7. High throughput sample preparation in combination with gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-MS/MS): a smart procedure for (ultra)trace analysis of brominated flame retardants in fish.

    Science.gov (United States)

    Kalachova, Kamila; Cajka, Tomas; Sandy, Chris; Hajslova, Jana; Pulkrabova, Jana

    2013-02-15

    In this study, gas chromatography (GC) coupled to triple quadrupole tandem mass spectrometry (MS/MS) operated in electron ionisation mode (EI) has been shown to be an effective tool for the (ultra)trace analysis of several representative brominated flame retardants (BFRs) including polybrominated diphenyl ethers (PBDEs), pentabromotoluene (PBT), pentabromoethylbenzene (PBEB), etc. in complex food and environmental matrices. Using this type of instrumentation, improved selectivity and sensitivity of the instrumental analysis was achieved. In addition to GC-MS/MS (EI), a GC-MS method employing QqQ as a single quadrupole in negative chemical ionisation (NCI) mode was also developed, as this technique might be preferred for those compounds where EI did not provide suitable (intensive enough) mass transitions (e.g., decabromodiphenyl ethane). Following the development of the GC-MS/MS method, a substantial simplification of the sample preparation method was achieved by employing an ethyl acetate QuEChERS-based extraction followed by silica minicolumn clean-up. Using this novel approach, six samples may be prepared in approx. one hour, thus significant time savings were achieved compared to routinely used methods. In addition, the method employs the reduced amounts of organic solvent and other chemicals. Under the optimised conditions, recoveries of all target analytes using both GC-MS/MS (EI) and GC-MS (NCI) were within the range of 70-119% and repeatabilities of the analytical procedure were ≤ 16% at all three spiking levels (0.1, 1 and 5 μg kg(-1)). Regarding quantification limits (LOQs), as expected, a single quadruple operated in NCI provided significantly lower LOQs compared to EI. However, using the triple quadrupole mass analyser, comparable LOQs were achieved for both methods (0.005-1 μg kg(-1) and 0.005-0.1 μg kg(-1) for GC-MS/MS (EI) and GC-MS (NCI), respectively). Moreover, when highly selective mass transitions in GC-MS/MS (EI) were used for

  8. Max-plus-linear model-based predictive control for constrained hybrid systems:linear programming solution

    Institute of Scientific and Technical Information of China (English)

    Yuanyuan ZOU; Shaoyuan LI

    2007-01-01

    In this paper,a linear programming method is proposed to solve model predictive control for a class of hybrid systems.Firstly,using the(max,+)algebra,a typical subclass of hybrid systems called max-plus-linear(MPL)systems is obtained.And then,model predictive control(MPC)framework is extended to MPL systems.In general,the nonlinear optimization approach or extended linear complementarity problem(ELCP)were applied to solve the MPL-MPC optimization problem.A new optimization method based on canonical forms for max-min-plus-scaling(MMPS)functions (using the operations maximization,minimization,addition and scalar multiplication)with linear constraints on the inputs is presented.The proposed approach consists in solving several linear programming problems and is more efficient than nonlinear optimization.The validity of the algorithm is illustrated by an example.

  9. Liquid chromatography coupled with ultraviolet absorbance detection, electrospray ionization, collision-induced dissociation and tandem mass spectrometry on a triple quadrupole for the on-line characterization of polyphenols and methylxanthines in green coffee beans.

    Science.gov (United States)

    Alonso-Salces, Rosa Maria; Guillou, Claude; Berrueta, Luis A

    2009-02-01

    Liquid chromatography coupled with a photodiode array detector, electrospray ionization, collision-induced dissociation and tandem mass spectrometry (LC-DAD/ESI-CID-MS/MS) on a triple quadrupole (QqQ) has been used to detect and characterize polyphenols and methylxanthines in green coffee beans: three phenolic acids (caffeic acid, ferulic acid and dimethoxycinnamic acid), three isomeric caffeoylquinic acids (M(r) 354), three feruloylquinic acids (M(r) 368), one p-coumaroylquinic acid (M(r) 338), three dicaffeoylquinic acids (M(r) 516), three feruloyl-caffeoylquinic acids (M(r) 530), four p-coumaroyl-caffeoylquinic acids (M(r) 500), three diferuloylquinic acids (M(r) 544), six dimethoxycinnamoyl-caffeoylquinic acids (M(r) 544), three dimethoxycinnamoyl-feruloylquinic acids (M(r) 558), six cinnamoyl-amino acid conjugates, three cinnamoyl glycosides, and three methylxanthines (caffeine, theobromine and theophylline). Dimethoxycinnamic acid, three isomers of dimethoxycinnamoyl-caffeoylquinic acids and another three of dimethoxycinnamoyl-feruloylquinic acids, as well as the three cinnamoyl glycosides, had not previously been reported in coffee beans. Structures have been assigned on the basis of the complementary information obtained from UV-visible spectra, relative hydrophobicity, scan mode MS spectra, and fragmentation patterns in MS(2) spectra (both in the positive and negative ion modes) obtained using a QqQ at different collision energies. A structure diagnosis scheme is provided for the identification of different isomers of polyphenols and methylxanthines.

  10. Analysis of 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues in chlorine-treated water by gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS).

    Science.gov (United States)

    Planas, Carles; Ventura, Francesc; Caixach, Josep; Martín, Jordi; Boleda, M Rosa; Paraira, Miquel

    2015-11-01

    A simple, selective and sensitive method for the analysis of the strong mutagen 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX) and its brominated analogues (BMXs) in chlorine-treated water has been developed. The method is based on gas chromatography coupled to triple quadrupole tandem mass spectrometry (GC-QqQ-MS/MS), previous liquid-liquid extraction (LLE) of a smaller sample volume compared to other methods and on-line derivatization with a silylation reactive. GC-QqQ-MS/MS has been raised as an alternative easier to perform than gas chromatography coupled to high resolution mass spectrometry (GC-HRMS) for the analysis of MX and BMXs, and it allows to achieve low LODs (0.3 ng/L for MX and 0.4-0.9 ng/L for BMXs). This technique had not been previously described for the analysis of MX and BMXs. Quality parameters were calculated and real samples related to 3 drinking water treatment plants (DWTPs), tap water and both untreated and chlorinated groundwater were analyzed. Concentrations of 0.3-6.6 ng/L for MX and 1.0-7.3 ng/L for BMXs were detected. Results were discussed according to five of the main factors affecting MX and BMXs formation in chlorine-treated water (organic precursors, influence of bromide ions, evolution of MX and BMXs in the drinking water distribution system, groundwater chlorination and infiltration of water coming from chlorination processes in groundwater).

  11. Rapid and sensitive analysis of phthalate metabolites, bisphenol A, and endogenous steroid hormones in human urine by mixed-mode solid-phase extraction, dansylation, and ultra-performance liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Wang, He-xing; Wang, Bin; Zhou, Ying; Jiang, Qing-wu

    2013-05-01

    Steroid hormone levels in human urine are convenient and sensitive indicators for the impact of phthalates and/or bisphenol A (BPA) exposure on the human steroid hormone endocrine system. In this study, a rapid and sensitive method for determination of 14 phthalate metabolites, BPA, and ten endogenous steroid hormones in urine was developed and validated on the basis of ultra-performance liquid chromatography coupled with electrospray ionization triple quadrupole mass spectrometry. The optimized mixed-mode solid phase-extraction separated the weakly acidic or neutral BPA and steroid hormones from acidic phthalate metabolites in urine: the former were determined in positive ion mode with a methanol/water mobile phase containing 10 mM ammonium formate; the latter were determined in negative ion mode with a acetonitrile/water mobile phase containing 0.1 % acetic acid, which significantly alleviated matrix effects for the analysis of BPA and steroid hormones. Dansylation of estrogens and BPA realized simultaneous and sensitive analysis of the endogenous steroid hormones and BPA in a single chromatographic run. The limits of detection were less than 0.84 ng/mL for phthalate metabolites and less than 0.22 ng/mL for endogenous steroid hormones and BPA. This proposed method had satisfactory precision and accuracy, and was successfully applied to the analyses of human urine samples. This method could be valuable when investigating the associations among endocrine-disrupting chemicals, endogenous steroid hormones, and relevant adverse outcomes in epidemiological studies.

  12. A Focused Multiple Reaction Monitoring (MRM Quantitative Method for Bioactive Grapevine Stilbenes by Ultra-High-Performance Liquid Chromatography Coupled to Triple-Quadrupole Mass Spectrometry (UHPLC-QqQ

    Directory of Open Access Journals (Sweden)

    Elías Hurtado-Gaitán

    2017-03-01

    Full Text Available Grapevine stilbenes are a family of polyphenols which derive from trans-resveratrol having antifungal and antimicrobial properties, thus being considered as phytoalexins. In addition to their diverse bioactive properties in animal models, they highlight a strong potential in human health maintenance and promotion. Due to this relevance, highly-specific qualitative and quantitative methods of analysis are necessary to accurately analyze stilbenes in different matrices derived from grapevine. Here, we developed a rapid, sensitive, and specific analysis method using ultra-high-performance liquid chromatography coupled to triple-quadrupole mass spectrometry (UHPLC-QqQ in MRM mode to detect and quantify five grapevine stilbenes, trans-resveratrol, trans-piceid, trans-piceatannol, trans-pterostilbene, and trans-ε-viniferin, whose interest in relation to human health is continuously growing. The method was optimized to minimize in-source fragmentation of piceid and to avoid co-elution of cis-piceid and trans-resveratrol, as both are detected with resveratrol transitions. The applicability of the developed method of stilbene analysis was tested successfully in different complex matrices including cellular extracts of Vitis vinifera cell cultures, reaction media of biotransformation assays, and red wine.

  13. Direct analysis of 18 flavonol glycosides, aglycones and terpene trilactones in Ginkgo biloba tablets by matrix solid phase dispersion coupled with ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry.

    Science.gov (United States)

    Liu, Xin-Guang; Yang, Hua; Cheng, Xiao-Lan; Liu, Lei; Qin, Yong; Wang, Qi; Qi, Lian-Wen; Li, Ping

    2014-08-01

    Analysis and quality control of Ginkgo biloba have been comprehensively studied. However, little attention has been devoted to the simultaneous extraction and analysis of flavonols and terpene trilactones, especially for direct quantification of flavonol glycosides. This work described a rapid strategy for one-step extraction and quantification of the components. A matrix solid phase dispersion (MSPD) method was designed for the extraction of ginkgo ingredients and compared with the heat-reflux and ultrasonic extraction methods. An ultra-high performance liquid chromatography (UHPLC)-tandem-triple-quadrupole-mass spectrometry (QQQ-MS) method was developed for detection of the 18 components, including 10 original flavonol glycosides, 3 aglycones, and 5 lactones. Subsequently, the proposed strategy was used for the analysis of 12 G. biloba tablets. Results showed that MSPD produced comparable extraction efficiency but consumed less time and required lower solvent volumes compared with conventional methods. Without hydrolysis, the concentration detected was much closer to the original in the sample. The total flavonol glycoside contents in ginkgo tablets ranged from 3.59 to 125.21μgmg(-1), and the terpene trilactone varied from 3.45 to 57.8μgmg(-1) among different manufacturers. In conclusion, the proposed MSPD and UHPLC-QQQ-MS is rapid and sensitive in providing comprehensive profile of chemical constituents especially the genuine flavonol glycosides for improved quality control of ginkgo products.

  14. Determination of polybrominated diphenyl ethers in fish tissues by matrix solid-phase dispersion and gas chromatography coupled to triple quadrupole mass spectrometry: case study on European eel (Anguilla anguilla) from Mediterranean coastal lagoons.

    Science.gov (United States)

    Labadie, Pierre; Alliot, Fabrice; Bourges, Catherine; Desportes, Annie; Chevreuil, Marc

    2010-08-24

    This paper describes the development and validation of an analytical methodology to determine 28 polybrominated diphenyl ethers (PBDEs) in European eel (Anguilla anguilla) tissues using matrix solid-phase dispersion (MSPD) and gas chromatography coupled to triple quadrupole mass spectrometry (GC-QQQ-MS/MS). A total of 28 PBDEs were targeted, including tri- to deca-brominated congeners. The robustness and effectiveness of the proposed sample preparation procedure was demonstrated in lipid-rich eel tissues. The use of batch MSPD with activated silica gel and H(2)SO(4)-impregnated silica gel, followed by H(2)SO(4) digestion and multilayer cartridge clean-up allowed for complete lipid removal and eliminated matrix effects during GC-QQQ-MS/MS analysis. The average PBDE recoveries from eel muscle samples spiked with PBDEs at two levels were in the range 56.2-119.0%. Precision was satisfactory since relative standard deviations were lower than 19.6%, regardless of spike level, and method quantification limits ranged between 1 and 170 pg g(-1) (wet weight). The method demonstrated its successful application for the analysis of eel samples from two coastal lagoons located on the western French Mediterranean coast. All samples tested positive, but for tri- to hexa-brominated congeners only and total PBDE levels observed in this study were in the range 0.08-1.80 ng g(-1) wet weight.

  15. 溴化衍生-三重四极杆气质联用法测定地表水中丙烯酰胺%Determination of Acrylamide in Surface Water by Brominating Derivation-Gas Chromatography Coupled with Triple Quadrupole Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    吕康乐; 宋俊密

    2016-01-01

    Acrylamide in surface water was determined in the form of α,β-dibromo acrylamide by brominating derivatization-liquid/liquid extraction-gas chromatography coupled with triple quadrupole mass spectrometry.The linearity range was from 20.0 μg/L to 500 μg/L with the correlation coefficient 0.998, and the detection limit was 0.08μg/L.Average spiked recoveries in two levels of 0.300μg/L and 2.00μg/L were 87.5%and 92.2%, respectively.The relative standard deviations of 7 measurement results were 9.1% and 6.1%.The samples from Lanzhou section of the Yellow River and tap water of laboratory were detected, the target was not detected in both samples.%采用溴化衍生-液液萃取法处理地表水,用三重四极杆气相色谱质谱联用仪测定样品中α,β-二溴丙烯酰胺,再换算成丙烯酰胺的质量浓度,该方法在20.0μg/L~500μg/L范围内线性良好,相关系数r为0.998,方法检出限为0.08μg/L。实际水样2个质量浓度水平的平均加标回收率分别为87.5%和92.2%,7次测定结果的RSD分别为9.1%和6.1%。用该方法测定黄河兰州段的黄河水和实验室自来水,结果均未检出。

  16. Simultaneous Determination of Fifteen Constituents of Jitai Tablet Using Ultra High-Performance Liquid Chromatography Coupled with Triple Quadrupole Electrospray Tandem Mass Spectrometry

    Directory of Open Access Journals (Sweden)

    Shuping Wang

    2014-01-01

    Full Text Available An ultra-high-performance liquid chromatography-electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS method was developed for simultaneous determination of fifteen constituents in Jitai tablet (JTT, a complex Traditional Chinese Medicine prescription (TCMP used in treating opiate addiction. Benefitting from a small particle size (1.8 µm C18 column, accelerated analysis with satisfactory resolution, sensitivity and selectivity were achieved in a single run within 7 min with linear gradient elution of acetonitrile-0.1% (v/v formic acid in water. The analytical signal was obtained by multiple reaction monitoring transitions via electrospray ionization source operating in both positive and negative ionization mode. The approach was validated for linearity, sensitivity, precision, repeatability, stability and recovery. All analytes showed good linearity over a wide concentration range (r > 0.99. The method limits ranged from 0.03 ng/mL to 19.35 ng/mL which are sensitive enough for quality control studies. The developed method was successfully applied to the simultaneous determination of fifteen constituents in JTT. In conclusion, our experimental results demonstrate that UHPLC-ESI-MS/MS is a useful approach for the overall quality assessment of complex TCMPs.

  17. A generalized hybrid transfinite element computational approach for nonlinear/linear unified thermal/structural analysis

    Science.gov (United States)

    Tamma, Kumar K.; Railkar, Sudhir B.

    1987-01-01

    The present paper describes the development of a new hybrid computational approach for applicability for nonlinear/linear thermal structural analysis. The proposed transfinite element approach is a hybrid scheme as it combines the modeling versatility of contemporary finite elements in conjunction with transform methods and the classical Bubnov-Galerkin schemes. Applicability of the proposed formulations for nonlinear analysis is also developed. Several test cases are presented to include nonlinear/linear unified thermal-stress and thermal-stress wave propagations. Comparative results validate the fundamental capablities of the proposed hybrid transfinite element methodology.

  18. Effect of drying methods on the free and conjugated bufadienolide content in toad venom determined by ultra-performance liquid chromatography-triple quadrupole mass spectrometry coupled with a pattern recognition approach.

    Science.gov (United States)

    Zhou, Jing; Gong, Yan; Ma, Hongyue; Wang, Honglan; Qian, Dawei; Wen, Hongmei; Liu, Rui; Duan, Jinao; Wu, Qinan

    2015-10-10

    Drying is a useful technique for extending the shelf-life of biological products and enabling long-term storage; however, improper drying can reduce the chemical quality of the products. In this study, we used ultra-performance liquid chromatography-triple quadrupole/mass spectrometry (LC-MS/MS) and multivariate statistical analysis to investigate the effects of four drying methods (V: vacuum-drying at 60°C, F: freeze-drying, H: air-drying at 60°C and R: air-drying at room temperature) on the levels of 36 bufadienolides in toad venom. Vacuum-drying at 60°C produced the highest quality dried toad venom in terms of total bufadienolide content, whereas traditional air-drying at room temperature (RT) to dehydrate the toad venom led to a dramatic loss in free and conjugated bufadienolides, reaching up to 60% and 70%, respectively. Assaying for free bufadienolides ranked the drying methods as V≈F>H>R, whereas assaying for conjugated bufadienolides slightly changed the order to V>F≈H>R. Furthermore, we identified 21 bufadienolides as biomarkers responsible for the decline in the quality of dried toad venom, whose loss varied from 1.5-fold to 100-fold. Of these biomarkers, group I bufadienolides that contain 16-OAc (e.g., cinobufagin and its hydroxyl or arginine ester derivatives) were characteristic components and were reduced to trace levels (loss of more than 10-fold) following traditional air-drying at RT. This might be attributed to the fact that most enzyme-sensitive bufadienolides were biotransformed or degraded at room temperature but were retained using other drying methods.

  19. A reliable solid phase microextraction-gas chromatography-triple quadrupole mass spectrometry method for the assay of selenomethionine and selenomethylselenocysteine in aqueous extracts: difference between selenized and not-enriched selenium potatoes.

    Science.gov (United States)

    Gionfriddo, Emanuela; Naccarato, Attilio; Sindona, Giovanni; Tagarelli, Antonio

    2012-10-17

    A new analytical approach is exploited in the assay of selenium speciation in selenized and not selenium enriched potatoes based on the widely available solid-phase microextraction (SPME) coupled to-GC-triple quadrupole mass spectrometry (SPME-GC-QqQ MS) method. The assay of selenomethionine (SeMet) and selenomethylselenocysteine (SeMeSeCys) in potatoes here reported provides clues to the effectiveness of SPME technique combined with gas chromatography-tandem mass spectrometry, which could be of general use. For the exploitation of the GC method, the selected analytes were converted into their N(O,S)-alkoxycarbonyl alkyl esters derivatives by direct treatment with alkyl chloroformate in aqueous extracts. The performance of five SPME fibers and three chloroformates were tested in univariate mode and the best results were obtained using the divinylbenzene/carboxen/polydimethylsiloxane fiber and propylchloroformate. The variables affecting the efficiency of SPME analysis were optimized by the multivariate approach of design of experiment (DoE) and, in particular, a central composite design (CCD) was applied. Tandem mass spectrometry in selected reaction monitoring (SRM) has allowed the elimination of matrix interferences, providing reconstructed chromatograms with well-resolved peaks and the achievement of very satisfactory detection and quantification limits. Both precision and recovery of the proposed protocol tested at concentration of 8 and 40 μg kg(-1) (dry matter), offered values ranging from 82.3 to 116.3% and from 8.5 to 13.1% for recovery and precision, respectively. The application of the method to commercial samples of selenized and not selenium enriched potatoes proved that the Se fertilization increases significantly the concentration of these bioavailable selenoamino acids.

  20. Triple-Quadrupole Inductively Coupled Plasma-Mass Spectrometry with a High-Efficiency Sample Introduction System for Ultratrace Determination of (135)Cs and (137)Cs in Environmental Samples at Femtogram Levels.

    Science.gov (United States)

    Zheng, Jian; Cao, Liguo; Tagami, Keiko; Uchida, Shigeo

    2016-09-06

    High yield fission products, (135)Cs and (137)Cs, have entered the environment as a result of anthropogenic nuclear activities. Analytical methods for ultratrace measurement of (135)Cs and (137)Cs are required for environmental geochemical and nuclear forensics studies. Here we report a highly sensitive method combining a desolvation sample introduction system (APEX-Q) with triple-quadrupole inductively coupled plasma mass spectrometry (AEPX-ICPMS/MS) for the determination of (135)Cs and (135)Cs/(137)Cs isotope ratio at femtogram levels. Using this system, we introduced only selected ions into the collision/reaction cell to react with N2O, significantly reducing the isobaric interferences ((135)Ba(+) and (137)Ba(+)) and polyatomic interferences ((95,97)Mo(40)Ar(+), (119)Sn(16)O(+), and (121)Sb(16)O(+)). Compared to the instrument setup of ICPMS/MS, the APEX-ICPMS/MS enables a 10-fold sensitivity increase. In addition, an effective chemical separation scheme consisting of ammonium molybdophosphate (AMP) Cs-selective adsorption and two-stage ion-exchange chromatographic separation was developed to remove major matrix and interfering elements from environmental samples (10-40 g). This separation method showed high decontamination factors (10(4)-10(7)) for major matrix elements (Al, Ca, K, Mg, Na, and Si) and interfering elements (Ba, Mo, Sb, and Sn). The high sensitivity of APEX-ICPMS/MS and the effective removal sample matrix allowed reliable analysis of (135)Cs and (137)Cs with extremely low detection limits (0.002 pg mL(-1), corresponding to 0.006 Bq mL(-1) (137)Cs). The accuracy and applicability of the APEX-ICPMS/MS method was validated by analysis of seven standard reference materials (soils, sediment, and plants). For the first time, ultratrace determination of (135)Cs and (135)Cs/(137)Cs isotope ratio at global fallout source environmental samples was achieved with the ICPMS technique.

  1. Rapid determination of {sup 135}Cs and precise {sup 135}Cs/{sup 137}Cs atomic ratio in environmental samples by single-column chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Guosheng [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564 (Japan); Division of Nuclear Technology and Applications, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049 (China); Beijing Engineering Research Center of Radiographic Techniques and Equipment, Beijing 100049 (China); Tazoe, Hirofumi [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564 (Japan); Yamada, Masatoshi, E-mail: myamada@hirosaki-u.ac.jp [Department of Radiation Chemistry, Institute of Radiation Emergency Medicine, Hirosaki University, 66-1 Hon-cho, Hirosaki, Aomori 036-8564 (Japan)

    2016-02-18

    For source identification, measurement of {sup 135}Cs/{sup 137}Cs atomic ratio not only provides information apart from the detection of {sup 134}Cs and {sup 137}Cs, but it can also overcome the application limit that measurement of the {sup 134}Cs/{sup 137}Cs ratio has due to the short half-life of {sup 134}Cs (2.06 y). With the recent advancement of ICP-MS, it is necessary to improve the corresponding separation method for rapid and precise {sup 135}Cs/{sup 137}Cs atomic ratio analysis. A novel separation and purification technique was developed for the new generation of triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The simple chemical separation, incorporating ammonium molybdophosphate selective adsorption of Cs and subsequent single cation-exchange chromatography, removes the majority of isobaric and polyatomic interference elements. Subsequently, the ICP-MS/MS removes residual interference elements and eliminates the peak tailing effect of stable {sup 133}Cs, at m/z 134, 135, and 137. The developed analytical method was successfully applied to measure {sup 135}Cs/{sup 137}Cs atomic ratios and {sup 135}Cs activities in environmental samples (soil and sediment) for radiocesium source identification. - Highlights: • A simple {sup 135}Cs/{sup 137}Cs analytical method was developed. • The separation procedure was based on AMP adsorption and one column chromatography. • {sup 135}Cs/{sup 137}Cs was measured by ICP-MS/MS. • Decontamination factors for Ba, Mo, Sb, and Sn were improved. • {sup 135}Cs/{sup 137}Cs atomic ratios of 0.341–0.351 were found in Japanese soil samples.

  2. Multiresidue method for the determination of pesticides in Oolong tea using QuEChERS by gas chromatography-triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Wu, Chia-Chang

    2017-08-15

    We propose a simple, rapid analytical method for determination of 89 pesticides in Oolong tea by GC/MS/MS. Samples were extracted via QuEChERS. The limits of detection and quantification range of the 89 pesticides were 1-25μgL(-1) and 10-50μgL(-1), respectively. Good separation was attained in less than 36min. A wide linear range of 1-250μgL(-1) was observed with r(2) values from 0.9955 to 0.9998. Pesticide-free tea powder spiked at 50 and 100μgL(-1). Recovery ranges of the 86 (50μgL(-1)) and 83 (100μgL(-1)) pesticides were from 60% to 120%. Relative standard deviations were less than 20%. The laboratory proficiency test (FAPAS, 2014) shows satisfactory (|z|pesticides in Oolong tea. Copyright © 2017 Elsevier Ltd. All rights reserved.

  3. 三重串联四极杆电感耦合等离子体质谱法 测定植源性中药材中总硫含量%Determination of Total Sulfur Dioxide in Chinese Herbal Medicines via Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    王晓伟; 刘景富; 关红; 王小艳; 邵兵; 张晶; 刘丽萍; 张妮娜

    2016-01-01

    As an important treatment method ,sulfur fumigation plays an essential role in the production and preservation of traditional Chinese herbal medicines .Although there is strict regulation on the use of sulfur dioxide ,the abuse of sulfur dioxide still occurred from time to time .And the public faces a high risk of exposure .Because of the poor precision and tedious prepara-tion procedures of traditional recommended titration ,the accurate and convenient determination of sulfur dioxide in Chinese herb-al medicines is still a critical analytical task for medicines safety and the public health .In this study ,an accurate ,high-through-put ,and convenient method for the absolute determination of SO2 in Chinese herbal medicines based on triple quadrupole induc-tively coupled plasma mass spectrometry (ICP-MS/MS) technique is developed .The study compared the quantitative ability for sulfur when the ICP-MS operated under traditional single quadrupole (QMS) mode and novel triple quadrupole (MS/MS) mode with three Reaction/Collision cell condition (no gas ,helium ,and oxygen) .The result indicated that when the concentration of sulfate ranging from 0 .5 to 100 mg · L -1 ,isotopic 34 S can be selected as quantitative ion either the ICP-MS operated under the QMS mode or MS/MS mode .The use of helium in the Reaction/Collision cell decreased the single intensity of background ions . Better than QMS mode ,the MS/MS mode can effectively reduced background interference .But there are no significant differ-ences about the linear range and limit of detection .However ,when the ICP-MS operated under MS/MS mode and oxygen was used as reaction gas in the Reaction/Collision cell ,the ICP-MS/MS provided an interference-free performance ,the linear range and limit of detection improved significantly .Either 32S or 34S exhibits an excellent linearity (r>0.999) over the concentration range of 0 .02~100 mg · L -1 ,with a limit of detection of 5.48 and 9.76 μg · L -1 for 32S16O2 -4 and 34

  4. Preconditioning Schur Complement Systems of Highly-Indefinite Linear Systems for a Parallel Hybrid Solve

    Institute of Scientific and Technical Information of China (English)

    I.Yamazaki; X.S.Li; E.G.Ng

    2010-01-01

    A parallel hybrid linear solver based on the Schur complement method has the potential to balance the robustness of direct solvers with the efficiency of precon-ditioned iterative solvers. However, when solving large-scale highly-indefinite linear systems, this hybrid solver often suffers from either slow convergence or large memory requirements to solve the Schur complement systems. To overcome this challenge, we in this paper discuss techniques to preprocess the Schur complement systems in paral-lel. Numerical results of solving large-scale highly-indefinite linear systems from various applications demonstrate that these techniques improve the reliability and performance of the hybrid solver and enable efficient solutions of these linear systems on hundreds of processors, which was previously infeasible using existing state-of-the-art solvers.

  5. Screening of inhibitors of angiotensin-converting enzyme (ACE) employing high performance liquid chromatography-electrospray ionization triple quadrupole mass spectrometry (HPLC-ESI-QqQ-MS).

    Science.gov (United States)

    Musharraf, Syed Ghulam; Bhatti, Muhammad Salman; Choudhary, Muhammad Iqbal; Rahman, Atta-Ur

    2017-04-01

    Angiotensin-converting enzyme (ACE) plays a key role in regulating blood pressure in the body by converting the angiotensin I (AI) into angiotensin II (AII). Angiotensin II is a potent vaso-active peptide that causes arterioles to constrict, resulting in increased blood pressure. A rapid and sensitive method for the identification of inhibitors of ACE was developed, and optimized employing HPLC-ESI-QqQ-MS. In this assay, angiotensin I substrate was converted into the product angiotensin II with the catalytic action of ACE. A calibration curve for depleting concentration of angiotensin I was developed and linearity of R(2)=0.999 with a remarkably low concentration of substrate range 20-200nM. The limit of detection and quantification of angiotensin I was found to be 1.93 and 5.84nM, respectively. The enzymatic reaction was optimized for incubation time, concentration, and volume of enzyme and substrate. All reactions were performed at 37°C at pH7.5 with standard incubation time of 20min. Two standard inhibitors, Captopril and Lisinopril, were checked through the newly developed method for their inhibitory potential, and their IC50 values were found to be 3.969 and 0.852μM, respectively. Reproducibility and precision analysis of different experiments showed <9.9% RSD. The developed method can be used for the identification of new ACE inhibitors.

  6. Determination of phthalate esters in vegetable oils using direct immersion solid-phase microextraction and fast gas chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Barp, Laura; Purcaro, Giorgia; Franchina, Flavio A; Zoccali, Mariosimone; Sciarrone, Danilo; Tranchida, Peter Q; Mondello, Luigi

    2015-08-01

    Phthalates are a group of synthetic compounds mainly used as plasticizers, which have been classified as endocrine-disrupting chemicals and potential human-cancer causing agents. They can be found in high amounts in foods, deriving mainly from plastic packaging. The analytical determination of these compounds is very challenging since they are ubiquitous. Therefore, minimization of sample manipulation is highly desirable. The present work exploited the application of a solid-phase microextraction method for the analysis of phthalates in vegetable oil. A preliminary comparison between a polydimethylsiloxane (PDMS) and a Carbopack Z/PDMS fiber was carried out both in the headspace and direct immersion extraction modes. Before immersing the fiber, a rapid liquid-liquid extraction was performed using acetonitrile to remove the bulk of triglycerides. PDMS in the direct immersion mode showed the best performance. The method was fully validated obtaining a good linearity with a coefficient of correlation of over 0.9960 for all compounds, repeatability and accuracy values generally better than 10%, and very good limit of quantification values.

  7. Simultaneous qualitative and quantitative analysis of 21 mycotoxins in Radix Paeoniae Alba by ultra-high performance liquid chromatography quadrupole linear ion trap mass spectrometry and QuEChERS for sample preparation.

    Science.gov (United States)

    Xing, Yanyan; Meng, Wenting; Sun, Wanyang; Li, Dongxiang; Yu, Zhiguo; Tong, Ling; Zhao, Yunli

    2016-09-15

    A high-throughput method for simultaneous qualitative and quantitative analysis of 21 mycotoxins in Radix Paeoniae Alba (RPA) was developed by coupling the modified QuEChERS method with ultra-high performance liquid chromatography quadrupole linear ion trap mass spectrometry (UHPLC-QqLIT-MS). The 21 mycotoxins were extracted and cleaned up using QuEChERS-based procedure, then further separated on a C18 column and detected by a hybrid triple quadrupole linear ion trap mass spectrometer equipped with electrospray ionization source in the multiple reaction monitoring-information dependent acquisition-enhanced product ion (MRM-IDA-EPI) mode. Under this technique, 13 mycotoxins were detected using acetonitrile and water containing 0.1% formic acid as the mobile phase in positive mode while the other 8 mycotoxins were detected using acetonitrile and water containing 0.1% ammonia as the mobile phase in negative mode. The calibration curves of all analytes showed good linearity (r(2)>0.995) within test ranges. The limits of detection and quantification ranged from 0.031 to 5.4μg/kg and 0.20 to 22μg/kg, respectively. Additionally, recoveries were all above 75.3% with relative standard deviations within 15%. The method proposed herein with significant advantages including simple pretreatment, rapid determination as well as high sensitivity, accuracy and throughput would be a preferred candidate for the determination and quantification of multi-class mycotoxin contaminants in real samples.

  8. Differentiation of various traditional Chinese medicines derived from animal bile and gallstone: simultaneous determination of bile acids by liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Qiao, Xue; Ye, Min; Pan, De-lin; Miao, Wen-juan; Xiang, Cheng; Han, Jian; Guo, De-an

    2011-01-01

    Animal biles and gallstones are popularly used in traditional Chinese medicines, and bile acids are their major bioactive constituents. Some of these medicines, like cow-bezoar, are very expensive, and may be adulterated or even replaced by less expensive but similar species. Due to poor ultraviolet absorbance and structural similarity of bile acids, effective technology for species differentiation and quality control of bile-based Chinese medicines is still lacking. In this study, a rapid and reliable method was established for the simultaneous qualitative and quantitative analysis of 18 bile acids, including 6 free steroids (cholic acid, chenodeoxycholic acid, deoxycholic acid, lithocholic acid, hyodeoxycholic acid, and ursodeoxycholic acid) and their corresponding glycine conjugates and taurine conjugates, by using liquid chromatography coupled with tandem mass spectrometry (LC/MS/MS). This method was used to analyze six bile-based Chinese medicines: bear bile, cattle bile, pig bile, snake bile, cow-bezoar, and artificial cow-bezoar. Samples were separated on an Atlantis dC₁₈ column and were eluted with methanol-acetonitrile-water containing ammonium acetate. The mass spectrometer was monitored in the negative electrospray ionization mode. Total ion currents of the samples were compared for species differentiation, and the contents of bile acids were determined by monitoring specific ion pairs in a selected reaction monitoring program. All 18 bile acids showed good linearity (r² > 0.993) in a wide dynamic range of up to 2000-fold, using dehydrocholic acid as the internal standard. Different animal biles could be explicitly distinguished by their major characteristic bile acids: tauroursodeoxycholic acid and taurochenodeoxycholic acid for bear bile, glycocholic acid, cholic acid and taurocholic acid for cattle bile, glycohyodeoxycholic acid and glycochenodeoxycholic acid for pig bile, and taurocholic acid for snake bile. Furthermore, cattle bile, cow

  9. Linear Viscoelasticity of Spherical SiO 2 Nanoparticle-Tethered Poly(butyl acrylate) Hybrids

    KAUST Repository

    Goel, Vivek

    2010-12-01

    The melt state linear viscoelastic properties of spherical silica nanoparticles with grafted poly(n-butyl acrylate) chains of varying molecular weight were probed using linear small amplitude dynamic oscillatory measurements and complementary linear stress relaxation measurements. While the pure silica-tethered-polymer hybrids with no added homopolymer exhibit solid-like response, addition of matched molecular weight free matrix homopolymer chains to this hybrid, at low concentrations of added homopolymer, maintains the solid-like response with a lowered modulus that can be factored into a silica concentration dependence and a molecular weight dependence. While the silica concentration dependence of the modulus is strong, the dependence on molecular weight is weak. On the other hand, increasing the amount of added homopolymer changes the viscoelastic response to that of a liquid with a relaxation time that scales exponentially with hybrid concentration. © 2010 American Chemical Society.

  10. Exciton dynamics and non-linearities in two-dimensional hybrid organic perovskites

    Science.gov (United States)

    Abdel-Baki, K.; Boitier, F.; Diab, H.; Lanty, G.; Jemli, K.; Lédée, F.; Garrot, D.; Deleporte, E.; Lauret, J. S.

    2016-02-01

    Due to their high potentiality for photovoltaic applications or coherent light sources, a renewed interest in hybrid organic perovskites has emerged for few years. When they are arranged in two dimensions, these materials can be considered as hybrid quantum wells. One consequence of the unique structure of 2D hybrid organic perovskites is a huge exciton binding energy that can be tailored through chemical engineering. We present experimental investigations of the exciton non-linearities by means of femtosecond pump-probe spectroscopy. The exciton dynamics is fitted with a bi-exponential decay with a free exciton life-time of ˜100 ps. Moreover, an ultrafast intraband relaxation (energy.

  11. Development and application of a high-throughput sample cleanup process based on 96-well plate for simultaneous determination of 16 steroids in biological matrices using liquid chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Luo, Guanzhong; Li, Youxin; Bao, James J

    2016-02-01

    A novel high-throughput sample pretreatment system was developed by the integration of protein precipitation (PP), phospholipid removal (PPR), and hollow fiber liquid-phase microextraction (HF-LPME) into two simple 96-well plates and a matching 96-grid lid. With this system, 16 steroids were separated from biological matrices of plasma, milk, and urine and analyzed by liquid chromatography-triple quadrupole mass spectrometry. In the tandem sample cleanup process, the prepositive PP and PPR step preliminarily removed some of the interferences from the biological matrices. The following HF-LPME step kept the residual interference out of the hollow fiber and enriched the steroids in the hollow fiber to achieve high sensitivity. By a series of method optimizations, acetonitrile was chosen as the crash solvent for PP and PPR. A mixture of octanol and toluene (1:1 v/v) was used as the acceptor phase for HF-LPME. The extraction was conducted at 80 rpm for 50 min in a donor phase containing 1 mL 20% sodium chloride at 25 °C. Under these conditions, the limits of detection for the 16 steroids were 3.6-300.0 pg(.)mL(-1) in plasma, 3.0-270.0 pg·mL(-1) in milk, and 2.2-210.0 pg(.)mL(-1) in urine. The recoveries of the 16 steroids were 81.9-97.9% in plasma (relative standard deviation 1.0-8.0%), 80.6-97.7% in milk (relative standard deviation 0.8-5.4%), and 87.3-98.7% in urine (relative standard deviation 1.0-4.9%). Further, the integrated 96-well platform of PP, PPR, and HF-LPME enabled us to run this assay in an automatic and high-throughput fashion. The reliability of the method was further corroborated by evaluation of its applicability in plasma and urine samples from volunteers and fresh bovine milk from local dairy enterprises.

  12. Trace analysis of pesticides in paddy field water by direct injection using liquid chromatography-quadrupole-linear ion trap-mass spectrometry.

    Science.gov (United States)

    Pareja, Lucía; Martínez-Bueno, M J; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, A R

    2011-07-29

    A multiresidue method was developed for the quantification and confirmation of 70 pesticides in paddy field water. After its filtration, water was injected directly in a liquid chromatograph coupled to a hybrid triple quadrupole-linear ion trap-mass spectrometer (QqLIT). The list of target analytes included organophosphates, phenylureas, sulfonylureas, carbamates, conazoles, imidazolinones and others compounds widely used in different countries where rice is cropped. Detection and quantification limits achieved were in the range from 0.4 to 80 ng L(-1) and from 2 to 150 ng L(-1), respectively. Correlation coefficients for the calibration curves in the range 0.1-50 μg L(-1) were higher than 0.99 except for diazinon (0.1-25 μg L(-1)). Only 9 pesticides presented more than 20% of signal suppression/enhancement, no matrix effect was observed in the studied conditions for the rest of the target pesticides. The method developed was used to investigate the occurrence of pesticides in 59 water samples collected in paddy fields located in Spain and Uruguay. The study shows the presence of bensulfuron methyl, tricyclazole, carbendazim, imidacloprid, tebuconazole and quinclorac in a concentration range from 0.08 to 7.20 μg L(-1). Copyright © 2011 Elsevier B.V. All rights reserved.

  13. GA and Lyapunov theory-based hybrid adaptive fuzzy controller for non-linear systems

    Science.gov (United States)

    Roy, Ananya; Das Sharma, Kaushik

    2015-02-01

    In this present article, a new hybrid methodology for designing stable adaptive fuzzy logic controllers (AFLCs) for a class of non-linear system is proposed. The proposed design strategy exploits the features of genetic algorithm (GA)-based stochastic evolutionary global search technique and Lyapunov theory-based local adaptation scheme. The objective is to develop a methodology for designing AFLCs with optimised free parameters and guaranteed closed-loop stability. Simultaneously, the proposed method introduces automation in the design process. The stand-alone Lyapunov theory-based design, GA-based design and proposed hybrid GA-Lyapunov design methodologies are implemented for two benchmark non-linear plants in simulation case studies with different reference signals and one experimental case study. The results demonstrate that the hybrid design methodology outperforms the other control strategies on the whole.

  14. High Bandwidth Rotary Fast Tool Servos and a Hybrid Rotary/Linear Electromagnetic Actuator

    Energy Technology Data Exchange (ETDEWEB)

    Montesanti, Richard Clement [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2005-09-01

    This thesis describes the development of two high bandwidth short-stroke rotary fast tool servos and the hybrid rotary/linear electromagnetic actuator developed for one of them. Design insights, trade-o® methodologies, and analytical tools are developed for precision mechanical systems, power and signal electronic systems, control systems, normal-stress electromagnetic actuators, and the dynamics of the combined systems.

  15. Global hybrids from the semiclassical atom theory satisfying the local density linear response

    CERN Document Server

    Fabiano, E; Cortona, P; Della Sala, F

    2015-01-01

    We propose global hybrid approximations of the exchange-correlation (XC) energy functional which reproduce well the modified fourth-order gradient expansion of the exchange energy in the semiclassical limit of many-electron neutral atoms and recover the full local density approximation (LDA) linear response. These XC functionals represent the hybrid versions of the APBE functional [Phys. Rev. Lett. 106, 186406, (2011)] yet employing an additional correlation functional which uses the localization concept of the correlation energy density to improve the compatibility with the Hartree-Fock exchange as well as the coupling-constant-resolved XC potential energy. Broad energetical and structural testings, including thermochemistry and geometry, transition metal complexes, non-covalent interactions, gold clusters and small gold-molecule interfaces, as well as an analysis of the hybrid parameters, show that our construction is quite robust. In particular, our testing shows that the resulting hybrid, including 20\\% o...

  16. Determination of 19 phthalate esters in cucumbers using QuEChERS coupled with gas chromatography-triple quadrupole mass spectrometry%QuEChERS-气相色谱-三重四极杆质谱法检测黄瓜中的19种邻苯二甲酸酯

    Institute of Scientific and Technical Information of China (English)

    孙欣; 齐莉; 秦廷亭; 王明林

    2014-01-01

    An efficient method using QuEChERS equipped with triple quadrupole GC-MS / MS for the simultaneous detection of 19 phthalate acid ester residues in cucumbers was established. The phthalate acid esters were extracted from cucumber samples by ultrasonic with acetonitrile. The extracts were salted out and centrifuged with anhydrous magnesium sulfate and sodium chloride. The supernatants were enriched by vacuum distillation,and then purified by C18 ad-sorbent. The 19 phthalate esters were separated on an HP-5ms UI column( 30 m × 0. 25 mm × 0. 25 μm),and determined using MS / MS in multiple reactions monitoring mode. The method showed favorable qualitative and quantitative analysis of the phthalate esters with good linearity (r ≥ 0. 999 5)in the linear range of 10-5 000 μg / kg and the limits of detection( LODs)were 0. 2-3. 5 μg / kg. With the proposed method,the recoveries were evaluated in cucumbers at the spiked levels of 10,100 and 500 μg / kg. The results showed that the average recoveries were ranged from 63. 3% -127. 8% and the relative standard deviations(RSDs)were 0. 5% -13. 3% . In short,the proposed method with high sensitivity and good accuracy can meet the determination requirements for multi-residues. Furthermore,the method can be applied for the simultaneous determination of phthalate acid esters in cucumbers.%建立了 QuEChERS 结合气相色谱-三重四极杆质谱联用仪同时检测黄瓜中19种邻苯二甲酸酯残留的方法。黄瓜样品采用乙腈超声提取,经无水硫酸镁和氯化钠盐析离心后减压蒸馏富集,然后用 C18吸附剂净化,经 HP-5ms UI 色谱柱分离后在多反应监测模式下进行测定。该方法在10~5000μg / kg 范围内线性关系良好( r ≥0.9995),检出限为0.2~3.5μg / kg。按照建立的方法分别进行了10、100和500μg / kg 3个添加水平的19种邻苯二甲酸酯的加标回收率试验,回收率为63.3%~127.8%,相对标准偏差为0.5%~13.3%。该

  17. An Effective Hybrid Artificial Bee Colony Algorithm for Nonnegative Linear Least Squares Problems

    Directory of Open Access Journals (Sweden)

    Xiangyu Kong

    2014-07-01

    Full Text Available An effective hybrid artificial bee colony algorithm is proposed in this paper for nonnegative linear least squares problems. To further improve the performance of algorithm, orthogonal initialization method is employed to generate the initial swarm. Furthermore, to balance the exploration and exploitation abilities, a new search mechanism is designed. The performance of this algorithm is verified by using 27 benchmark functions and 5 nonnegative linear least squares test problems. And the comparison analyses are given between the proposed algorithm and other swarm intelligence algorithms. Numerical results demonstrate that the proposed algorithm displays a high performance compared with other algorithms for global optimization problems and nonnegative linear least squares problems.

  18. Linear and Nonlinear Rheology Combined with Dielectric Spectroscopy of Hybrid Polymer Nanocomposites for Semiconductive Applications

    Science.gov (United States)

    Kádár, Roland; Abbasi, Mahdi; Figuli, Roxana; Rigdahl, Mikael; Wilhelm, Manfred

    2017-01-01

    The linear and nonlinear oscillatory shear, extensional and combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. The main focus was the influence of processing conditions on percolated poly(ethylene-butyl acrylate) (EBA) nanocomposite hybrids containing graphite nanoplatelets (GnP) and carbon black (CB). The rheological response of the samples was interpreted in terms of dispersion properties, filler distortion from processing, filler percolation, as well as the filler orientation and distribution dynamics inside the matrix. Evidence of the influence of dispersion properties was found in linear viscoelastic dynamic frequency sweeps, while the percolation of the nanocomposites was detected in nonlinearities developed in dynamic strain sweeps. Using extensional rheology, hybrid samples with better dispersion properties lead to a more pronounced strain hardening behavior, while samples with a higher volume percentage of fillers caused a drastic reduction in strain hardening. The rheo-dielectric time-dependent response showed that in the case of nanocomposites containing only GnP, the orientation dynamics leads to non-conductive samples. However, in the case of hybrids, the orientation of the GnP could be offset by the dispersing of the CB to bridge the nanoplatelets. The results were interpreted in the framework of a dual PE-BA model, where the fillers would be concentrated mainly in the BA regions. Furthermore, better dispersed hybrids obtained using mixing screws at the expense of filler distortion via extrusion processing history were emphasized through the rheo-dielectric tests. PMID:28336857

  19. Linear and Nonlinear Rheology Combined with Dielectric Spectroscopy of Hybrid Polymer Nanocomposites for Semiconductive Applications.

    Science.gov (United States)

    Kádár, Roland; Abbasi, Mahdi; Figuli, Roxana; Rigdahl, Mikael; Wilhelm, Manfred

    2017-01-24

    The linear and nonlinear oscillatory shear, extensional and combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. The main focus was the influence of processing conditions on percolated poly(ethylene-butyl acrylate) (EBA) nanocomposite hybrids containing graphite nanoplatelets (GnP) and carbon black (CB). The rheological response of the samples was interpreted in terms of dispersion properties, filler distortion from processing, filler percolation, as well as the filler orientation and distribution dynamics inside the matrix. Evidence of the influence of dispersion properties was found in linear viscoelastic dynamic frequency sweeps, while the percolation of the nanocomposites was detected in nonlinearities developed in dynamic strain sweeps. Using extensional rheology, hybrid samples with better dispersion properties lead to a more pronounced strain hardening behavior, while samples with a higher volume percentage of fillers caused a drastic reduction in strain hardening. The rheo-dielectric time-dependent response showed that in the case of nanocomposites containing only GnP, the orientation dynamics leads to non-conductive samples. However, in the case of hybrids, the orientation of the GnP could be offset by the dispersing of the CB to bridge the nanoplatelets. The results were interpreted in the framework of a dual PE-BA model, where the fillers would be concentrated mainly in the BA regions. Furthermore, better dispersed hybrids obtained using mixing screws at the expense of filler distortion via extrusion processing history were emphasized through the rheo-dielectric tests.

  20. Two Hybrid Methods for Solving Two-Dimensional Linear Time-Fractional Partial Differential Equations

    Directory of Open Access Journals (Sweden)

    B. A. Jacobs

    2014-01-01

    Full Text Available A computationally efficient hybridization of the Laplace transform with two spatial discretization techniques is investigated for numerical solutions of time-fractional linear partial differential equations in two space variables. The Chebyshev collocation method is compared with the standard finite difference spatial discretization and the absolute error is obtained for several test problems. Accurate numerical solutions are achieved in the Chebyshev collocation method subject to both Dirichlet and Neumann boundary conditions. The solution obtained by these hybrid methods allows for the evaluation at any point in time without the need for time-marching to a particular point in time.

  1. Non-fragile hybrid guaranteed cost control for a class of uncertain switched linear systems

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    This paper focuses on the problem of non-fragile hybrid guaranteed cost control for a class of uncertain switched linear systems. The controller gain to be designed is assumed to have additive gain variations. Based on multiple-Lyapunov function technique, the design of non-fragile hybrid guaranteed cost controllers is derived to make the corresponding closed-loop system asymptotically stable for all admissible uncertainties. Furthermore, a convex optimization approach with LMIs constraints is introduced to select the optimal non-fragile guaranteed cost controllers. Finally, a simulation example illustrates the effectiveness of the proposed approach.

  2. 罗丹明B衍生化超高效液相色谱三重四极杆质谱高灵敏测定人参二醇%Sensitive Determination of Panaxadiol Using Rhodamine B as Sensitizing Derivatization-Reagent by Ultrahigh Performance Liquid Chromatography-Triple Quadrupole Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    赵先恩; 吕涛; 魏娜; 朱树芸; 尤进茂

    2014-01-01

    Invirtueofthestrategyofultrasonic-assisteddispersiveliquid-liquidmicroextraction(UA-DLLME) combined with Rhodamine B derivatization, a new ultrahigh performance liquid chromatography-triple quadrupole mass spectrometry ( UHPLC-MS/MS) method was devepled for the sensitive determination of Panaxadiol ( PD) . UA-DLLME and derivatization conditions were investigated. PD in cosmetics and ginseng was extracted by UA-DLLME (150 μL of chloroform as extraction solvent and 500 of μL ethanol as disperser solvent, 3 min) . Using Rhodamine B as precolumn derivatization reagent, the stable derivative of PD was obtained in acetonitrile at 70 ℃ for 30 min under microwave radiation (800 W) with the catalyst of N,N'-carbonyldiimidazole ( CDI) and 4-dimethylaminopyridine ( DMAP) . And then the PD derivative was separated and detected within 3 min by multiple reaction monitoring ( MRM ) mode of UHPLC-MS/MS. LOD was 4. 0 ng/L, and the LOQ was 15. 0 ng/L. This method had good linearity, precision and recovery, and showed obvious advantages such as sensitivity and low matrix effect comparing to the previously reported methods.%以罗丹明B为质谱增敏衍生化试剂,标记羟基化合物,通过超声波辅助-分散液液微萃取( Ultrasonic assisted-dispersive liquid-liquid microextraction, UA-DLLME)和罗丹明B衍生化联合的策略,建立了超高效液相色谱三重四极杆质谱检测人参二醇( Panaxadiol, PD)的分析方法。化妆品和人参药材中PD经UA-DLLME进行萃取富集(150μL氯仿作为萃取剂,500μL乙醇作为分散剂,3 min),以罗丹明B为衍生试剂,在N,N-羰基二咪唑(N,N-Carbonyldiimidazole, CDI)和4-二甲氨基吡啶(4-Dimethylaminopyridine, DMAP)的催化作用下,70℃微波辅助衍生反应30 min得到稳定的衍生产物。PD衍生物的多反应监测( Multiple reaction monitoring, MRM)模式质谱测定3 min内完成,方法检出限4.0 ng/L,定量限15.0 ng/L,线性、精密度和回收率良好,与以往报道的方法相

  3. 气相色谱-三重四极杆串联质谱法测定白芍中99种农药残留%Determination of 99 pesticide residues in Paeoniae Radix Alba by gas chromatography-triple quadrupole tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    刘小勤; 佟玲; 孟文婷; 孙国祥

    2015-01-01

    A method was established for the simultaneous determination of 99 pesticide resi-dues with combination of solid-phase extraction technique ( SPE ) and gas chromatography-triple quadrupole tandem mass spectrometry( GC-QqQ-MS ). The sample was extracted with ethyl acetate,and cleaned-up by an amino SPE column. The extract was determined by GC-MS/MS in multi-reaction monitoring ( MRM ) mode, and matrix-matched internal standard method was applied to quantify the pesticides. The results of all the 99 pesticides showed good linearity in the range of 0. 001-0. 25 mg/L,with correlation coefficients(r2)> 0. 99. The limits of quantification( LOQs ) were between 0. 001-0. 050 mg/kg. The recoveries were between 66. 7% and 128. 0% with RSD values typically lower than 18. 3% at three spiked levels of 0. 05, 0. 10 and 0. 20 mg/kg. This method has been applied to determine thirteen batches of commer-cially available samples,chlorpyriphos-ethyl and p,p′-DDE were detected in four batches of Paeoniae Radix Alba. The method is highly accurate,reliable and sensitive for monitoring the 99 pesticide residues in Paeoniae Radix Alba.%采用固相萃取技术( SPE)结合气相色谱-三重四极杆质谱( GC-MS/MS)建立了白芍中99种农药同时检测的分析方法。试样用乙酸乙酯提取,采用氨基固相萃取柱净化后,在 GC-MS/MS 多反应监测( MRM)模式下进行检测,基质匹配标准曲线内标法定量。结果表明,99种农药在0.001~0.25 mg/L 范围内线性关系良好,相关系数( r2)大于0.99,方法定量限为0.001~0.050 mg/kg。加标水平为0.05、0.10和0.20 mg/kg时,99种农药的平均回收率为66.7%~128.0%,相对标准偏差( RSD,n=6)小于18.3%。对市售的13批样品进行测定,其中4批样品中检出微量的毒死蜱和 p,p′-滴滴伊。实验证明,建立的 SPE净化和 GC-QqQ-MS相结合的检测方法具有准确可靠、灵敏度高等优点,适用于白芍中多

  4. Determination of α-solanine,α-chaconine and solanidine in plasma and urine by ultra-performance liquid chromatography-triple quadrupole mass spectrometry%超高效液相色谱-三重四极杆质谱联用方法测定血浆和尿液中的α-龙葵碱、α-卡茄碱和茄啶

    Institute of Scientific and Technical Information of China (English)

    张秀尧; 蔡欣欣; 张晓艺

    2014-01-01

    建立了超高效液相色谱-三重四极杆质谱联用方法,检测血浆和尿液中的α-龙葵碱、α-卡茄碱和茄啶。样品经2%(v / v,下同)甲酸水溶液等量稀释,再经混合型阳离子交换固相萃取柱(MCX SPE)净化,以0.1%甲酸乙腈溶液和含0.05%甲酸的5 mmol / L 乙酸铵水溶液作为流动相进行梯度洗脱,在 UPLC BEH C 18色谱柱上实现分离,正离子电喷雾串联质谱多反应监测(ESI-MS / MS MRM)方式检测,基质匹配外标法定量。一次进样分析时间为5.5 min。血浆和尿液中3种待测物的线性范围均为0.3~100 ng / mL,相关系数为0.997~0.999;样品的检出限为0.1 ng / mL,定量限为0.3 ng / mL;血浆和尿液中的平均加标回收率分别为82%~112%和96%~114%,相对标准偏差为4.0%~16%和2.7%~17%(n =6)。方法简单、准确、灵敏,适用于马铃薯中毒检测。%An ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-MS / MS)method was developed for the determination of α-solanine,α-chaconine and solanidine in plasma and urine. The sample was acidified with aqueous solution containing 2%(v / v if not specified)formic acid,and then cleaned-up by solid-phase extraction with a mixed-mode cation exchange(MCX)cartridge. The analysis of the glycoalkaloids was carried out on an Acquity UPLC BEH C 18 column(50 mm×2. 1 mm,1. 7 μm)with gradient elution of acetoni-trile(containing 0. 1% formic acid)and H 2 O( containing 0. 05% formic acid and 5. 0 mmol / L ammonium acetate ). The analytes were detected by positive electrospray ionization tandem mass spectrometry in MRM mode,and quantified by external matrix-matched standard calibra-tion. The cycle time of each analysis was 5. 5 min. The calibration curves were linear in the range of 0. 3-100 ng / mL of the glycoalkaloids in plasma and urine. The correlation coefficients were 0. 997- 0. 999. The limits of detection( S / N = 3)and

  5. Analysis of drugs in plasma samples from schizophrenic patients by column-switching liquid chromatography-tandem mass spectrometry with organic-inorganic hybrid cyanopropyl monolithic column.

    Science.gov (United States)

    Domingues, Diego Soares; Souza, Israel Donizeti de; Queiroz, Maria Eugênia Costa

    2015-07-01

    This study reports on the development of a rapid, selective, and sensitive column-switching liquid chromatography-tandem mass spectrometry (LC-MS/MS) method to analyze sixteen drugs (antidepressants, anticonvulsants, anxiolytics, and antipsychotics) in plasma samples from schizophrenic patients. The developed organic-inorganic hybrid monolithic column with cyanopropyl groups was used for the first dimension of the column-switching arrangement. This arrangement enabled online pre-concentration of the drugs (monolithic column) and their subsequent analytical separation on an XSelect SCH C18 column. The drugs were detected on a triple quadrupole tandem mass spectrometer (multiple reactions monitoring mode) with an electrospray ionization source in the positive ion mode. The developed method afforded adequate linearity for the sixteen target drugs; the coefficients of determination (R(2)) lay above 0.9932, the interassay precision had coefficients of variation lower than 6.5%, and the relative standard error values of the accuracy ranged from -14.0 to 11.8%. The lower limits of quantification in plasma samples ranged from 63 to 1250pgmL(-1). The developed method successfully analyzed the target drugs in plasma samples from schizophrenic patients for therapeutic drug monitoring (TDM).

  6. A new mixed mode solid phase extraction strategy for opioids, cocaines, amphetamines and adulterants in human blood with hybrid liquid chromatography tandem mass spectrometry detection.

    Science.gov (United States)

    Dowling, Geraldine; Regan, Liam

    2011-04-05

    A rapid method has been developed to analyse morphine, codeine, 6-monoacetylmorphine, cocaine, benzoylecgonine, dihydrocodeine, cocaethylene, 3,4-methylenedioxyamphetamine, ketamine, 3,4-methylenedioxymethamphetamine, pseudoephedrine, lignocaine, benzylpiperazine, methamphetamine, amphetamine, methadone, phenethylamine and levamisole in human blood. Blood samples were cleaned up using mixed mode solid phase extraction using Evolute™ CX solid phase extraction cartridges and the sample aliquots were analysed by hybrid triple quadrupole linear ion trap (QTRAP) mass spectrometry with a runtime of 12.5 min. Multiple reaction monitoring (MRM) as survey scan and an enhanced product ion (EPI) scan as dependent scan were performed in an information-dependent acquisition (IDA) experiment. Finally, drug identification and confirmation was carried out by library search with a developed in-house MS/MS library based on EPI spectra at a collision energy spread of 35 ± 15 in positive mode and MRM ratios. The method was validated in blood, according to the criteria defined in Commission Decision 2002/657/EC. At least two MRM transitions for each substance were monitored in addition to EPI spectra. Deuterated analogues of analytes were used as internal standards for quantitation where possible. The method proved to be simple and time efficient and was implemented as an analytical strategy for the illicit drug monitoring of opioids, cocaines, amphetamines and adulterants in forensic cases of crime offenders, abusers or victims in the Republic of Ireland.

  7. The Complexity of Monotone Hybrid Logics over Linear Frames and the Natural Numbers

    CERN Document Server

    Göller, Stefan; Mundhenk, Martin; Schneider, Thomas; Thomas, Michael; Weiss, Felix

    2012-01-01

    Hybrid logic with binders is an expressive specification language. Its satisfiability problem is undecidable in general. If frames are restricted to the natural numbers or general linear orders, then satisfiability is known to be decidable, but of non-elementary complexity. In this paper, we consider monotone hybrid logics (i.e., the Boolean connectives are conjunction and disjunction only) over the natural numbers and general linear orders. We show that the satisfiability problem remains non-elementary over linear orders, but its complexity drops to PSPACE-completeness over natural numbers. We categorize the strict fragments arising from different combinations of modal and hybrid operators into NP-complete and tractable, and show that the latter cases are complete for NC1 or LOGSPACE. Interestingly, NP-completeness depends only on the fragment and not on the frame. For the cases above NP, satisfiability over linear orders is harder than over natural numbers, while below NP it is at most as hard. In addition ...

  8. Metabolic profile of naringenin in the stomach and colon using liquid chromatography/electrospray ionization linear ion trap quadrupole-Orbitrap-mass spectrometry (LC-ESI-LTQ-Orbitrap-MS) and LC-ESI-MS/MS.

    Science.gov (United States)

    Orrego-Lagarón, Naiara; Vallverdú-Queralt, Anna; Martínez-Huélamo, Miriam; Lamuela-Raventos, Rosa M; Escribano-Ferrer, Elvira

    2016-02-20

    Several biological activities (antioxidant, anti-inflammatory, anticarcinogenic) are attributed to naringenin (NAR)-a predominant flavonoid of citrus fruit and tomato-despite its low bioavailability after ingestion. NAR undergoes extensive metabolism when crossing the gastrointestinal tract, resulting in enteric, hepatic and microbial metabolites, some of them with recognized beneficial effects on human health. This study sought to provide new insights into the metabolism of NAR in regions of the gastrointestinal tract where it has been less studied: the stomach and colon. With this purpose, liquid chromatography coupled with an electrospray ionization hybrid linear ion trap quadrupole Orbitrap mass spectrometry technique (LC-ESI-LTQ-Orbitrap-MS) was used for an accurate identification of NAR metabolites, and liquid chromatography/electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) on a triple quadrupole was used for their identification and quantification. The combination of both analytical techniques provided a broader metabolic profile of NAR. As far as we know, this is the first in-depth metabolic profiling study of NAR in the stomach of mice. Three of the metabolites determined using the LC-LTQ-Orbitrap could not be identified by LC-ESI-MS/MS in stomach perfusion samples: apigenin, 3-(4-hydroxyphenyl) propionic acid and phloroglucinol. The number of colonic metabolites determined using the LTQ-Orbitrap-MS was more than twice the number identified by LC-ESI-MS/MS.

  9. A hybrid analysis method for linear dynamic soil-structure interaction in time and frequency domain

    Institute of Scientific and Technical Information of China (English)

    丁海平; 廖振鹏

    2001-01-01

    A hybrid analysis method in time and frequency domains for linear soil-structure interaction is presented. First, the time domain solution of the system with Rayleigh damping excited by a short time impulse is obtained by the decoupling numerical simulation technique of near-field wave motion. Then, the corresponding frequency domain solution can be got by Fourier transform. According to the relationship between damping value and dynamic re-sponse of a system, the solution of the system with complex damping can be got by Taylor expansion. The hybrid method makes the best of decoupling and explicit algorithm in time domain, and increases the calculation efficien-cy for linear soil-structure interaction analysis.

  10. A linear dispersion relation for the hybrid kinetic-ion/fluid-electron model of plasma physics

    CERN Document Server

    Told, Daniel; Astfalk, Patrick; Jenko, Frank

    2016-01-01

    A dispersion relation for a commonly used hybrid model of plasma physics is developed, which combines fully kinetic ions and a massless-electron fluid description. Although this model and variations of it have been used to describe plasma phenomena for about 40 years, to date there exists no general dispersion relation to describe the linear wave physics contained in the model. Previous efforts along these lines are extended here to retain arbitrary wave propagation angles, temperature anisotropy effects, as well as additional terms in the generalized Ohm's law which determines the electric field. A numerical solver for the dispersion relation is developed, and linear wave physics is benchmarked against solutions of a full Vlasov-Maxwell dispersion relation solver. This work opens the door to a more accurate interpretation of existing and future wave and turbulence simulations using this type of hybrid model.

  11. Screening methods for linear-scaling short-range hybrid calculations on CPU and GPU architectures

    Science.gov (United States)

    Beuerle, Matthias; Kussmann, Jörg; Ochsenfeld, Christian

    2017-04-01

    We present screening schemes that allow for efficient, linear-scaling short-range exchange calculations employing Gaussian basis sets for both CPU and GPU architectures. They are based on the LinK [C. Ochsenfeld et al., J. Chem. Phys. 109, 1663 (1998)] and PreLinK [J. Kussmann and C. Ochsenfeld, J. Chem. Phys. 138, 134114 (2013)] methods, but account for the decay introduced by the attenuated Coulomb operator in short-range hybrid density functionals. Furthermore, we discuss the implementation of short-range electron repulsion integrals on GPUs. The introduction of our screening methods allows for speedups of up to a factor 7.8 as compared to the underlying linear-scaling algorithm, while retaining full numerical control over the accuracy. With the increasing number of short-range hybrid functionals, our new schemes will allow for significant computational savings on CPU and GPU architectures.

  12. An Object Detection Method Using Wavelet Optical Flow and Hybrid Linear-Nonlinear Classifier

    Directory of Open Access Journals (Sweden)

    Pengcheng Han

    2013-01-01

    Full Text Available We propose a new computational intelligence method using wavelet optical flow and hybrid linear-nonlinear classifier for object detection. With the existing optical flow methods, it is difficult to accurately estimate moving objects with diverse speeds. We propose a wavelet-based optical flow method, which uses wavelet decomposition in optical flow motion estimation. The algorithm can accurately detect moving objects with variable speeds in a scene. In addition, we use the hybrid linear-nonlinear classifier (HLNLC to classify moving objects and static background. HLNLC transforms a nonoptimal scalar variable into its likelihood ratio and uses a scalar quantity as the decision variable. This approach is appropriate for the classification of optical flow feature vectors with unequal variance matrices. The experimental results confirm that our proposed object detection method has an improved accuracy and computation efficiency over other state-of-the-art methods.

  13. A Linear Approach for Depth and Colour Camera Calibration Using Hybrid Parameters

    Institute of Scientific and Technical Information of China (English)

    Ke-Li Cheng; Xuan Ju; Ruo-Feng Tong; Min Tang; Jian Chang; Jian-Jun Zhang

    2016-01-01

    Many recent applications of computer graphics and human computer interaction have adopted both colour cameras and depth cameras as input devices. Therefore, an effective calibration of both types of hardware taking different colour and depth inputs is required. Our approach removes the numerical difficulties of using non-linear optimization in previous methods which explicitly resolve camera intrinsics as well as the transformation between depth and colour cameras. A matrix of hybrid parameters is introduced to linearize our optimization. The hybrid parameters offer a transformation from a depth parametric space (depth camera image) to a colour parametric space (colour camera image) by combining the intrinsic parameters of depth camera and a rotation transformation from depth camera to colour camera. Both the rotation transformation and intrinsic parameters can be explicitly calculated from our hybrid parameters with the help of a standard QR factorisation. We test our algorithm with both synthesized data and real-world data where ground-truth depth information is captured by Microsoft Kinect. The experiments show that our approach can provide comparable accuracy of calibration with the state-of-the-art algorithms while taking much less computation time (1/50 of Herrera’s method and 1/10 of Raposo’s method) due to the advantage of using hybrid parameters.

  14. Exciton dynamics and non-linearities in two-dimensional hybrid organic perovskites

    Energy Technology Data Exchange (ETDEWEB)

    Abdel-Baki, K.; Boitier, F.; Diab, H.; Lanty, G.; Jemli, K.; Lédée, F.; Deleporte, E.; Lauret, J. S., E-mail: jean-sebastien.lauret@lac.u-psud.fr [Laboratoire Aimé Cotton, CNRS, Univ. Paris-Sud, ENS Cachan, Université Paris-Saclay, 91405 Orsay Cedex (France); Garrot, D. [GEMAC, CNRS, UVSQ, Université Paris-Saclay, 45 avenue des États Unis 78035 Versailles Cedex (France)

    2016-02-14

    Due to their high potentiality for photovoltaic applications or coherent light sources, a renewed interest in hybrid organic perovskites has emerged for few years. When they are arranged in two dimensions, these materials can be considered as hybrid quantum wells. One consequence of the unique structure of 2D hybrid organic perovskites is a huge exciton binding energy that can be tailored through chemical engineering. We present experimental investigations of the exciton non-linearities by means of femtosecond pump-probe spectroscopy. The exciton dynamics is fitted with a bi-exponential decay with a free exciton life-time of ∼100 ps. Moreover, an ultrafast intraband relaxation (<150 fs) is also reported. Finally, the transient modification of the excitonic line is analyzed through the moment analysis and described in terms of reduction of the oscillator strength and linewidth broadening. We show that excitonic non-linearities in 2D hybrid organic perovskites share some behaviours of inorganic semiconductors despite their high exciton binding energy.

  15. Characteristic Analysis and Control of a Hybrid Excitation Linear Eddy Current Brake

    Directory of Open Access Journals (Sweden)

    Baoquan Kou

    2015-07-01

    Full Text Available In this paper, a novel hybrid excitation linear eddy current brake is presented as a braking system for high-speed road and rail vehicles. The presence of the permanent magnets (PMs, whose flux lines in the primary core are oppositely directed with respect to the flux lines by the excitation windings, has the effect of mitigating the saturation of the iron in the teeth of the primary core. This allows the brake to be fed with more intense currents, improving the braking force. First, using the magnetic equivalent circuit method and the layer theory approach, the analytical model of the hybrid excitation linear eddy current brake was developed, which can account for the saturation effects occurring in the iron parts. The saturation effects make the design and control of eddy current brakes more difficult. Second, the relationship between the braking force characteristics and the design parameters were analyzed to provide useful information to the designers of eddy current brakes. Then, the controller of the hybrid excitation linear eddy current brake was designed to control the amplitude of the braking force. Finally, experimental measurements were conducted to verify the validity of the theoretical analysis.

  16. Application of Hybrid Optimization Algorithm in the Synthesis of Linear Antenna Array

    Directory of Open Access Journals (Sweden)

    Ezgi Deniz Ülker

    2014-01-01

    Full Text Available The use of hybrid algorithms for solving real-world optimization problems has become popular since their solution quality can be made better than the algorithms that form them by combining their desirable features. The newly proposed hybrid method which is called Hybrid Differential, Particle, and Harmony (HDPH algorithm is different from the other hybrid forms since it uses all features of merged algorithms in order to perform efficiently for a wide variety of problems. In the proposed algorithm the control parameters are randomized which makes its implementation easy and provides a fast response. This paper describes the application of HDPH algorithm to linear antenna array synthesis. The results obtained with the HDPH algorithm are compared with three merged optimization techniques that are used in HDPH. The comparison shows that the performance of the proposed algorithm is comparatively better in both solution quality and robustness. The proposed hybrid algorithm HDPH can be an efficient candidate for real-time optimization problems since it yields reliable performance at all times when it gets executed.

  17. Linear and Nonlinear Rheology Combined with Dielectric Spectroscopy of Hybrid Polymer Nanocomposites for Semiconductive Applications

    Directory of Open Access Journals (Sweden)

    Roland Kádár

    2017-01-01

    Full Text Available The linear and nonlinear oscillatory shear, extensional and combined rheology-dielectric spectroscopy of hybrid polymer nanocomposites for semiconductive applications were investigated in this study. The main focus was the influence of processing conditions on percolated poly(ethylene-butyl acrylate (EBA nanocomposite hybrids containing graphite nanoplatelets (GnP and carbon black (CB. The rheological response of the samples was interpreted in terms of dispersion properties, filler distortion from processing, filler percolation, as well as the filler orientation and distribution dynamics inside the matrix. Evidence of the influence of dispersion properties was found in linear viscoelastic dynamic frequency sweeps, while the percolation of the nanocomposites was detected in nonlinearities developed in dynamic strain sweeps. Using extensional rheology, hybrid samples with better dispersion properties lead to a more pronounced strain hardening behavior, while samples with a higher volume percentage of fillers caused a drastic reduction in strain hardening. The rheo-dielectric time-dependent response showed that in the case of nanocomposites containing only GnP, the orientation dynamics leads to non-conductive samples. However, in the case of hybrids, the orientation of the GnP could be offset by the dispersing of the CB to bridge the nanoplatelets. The results were interpreted in the framework of a dual PE-BA model, where the fillers would be concentrated mainly in the BA regions. Furthermore, better dispersed hybrids obtained using mixing screws at the expense of filler distortion via extrusion processing history were emphasized through the rheo-dielectric tests.

  18. Surpassing the no-cloning limit with a heralded hybrid linear amplifier for coherent states

    Science.gov (United States)

    Haw, Jing Yan; Zhao, Jie; Dias, Josephine; Assad, Syed M.; Bradshaw, Mark; Blandino, Rémi; Symul, Thomas; Ralph, Timothy C.; Lam, Ping Koy

    2016-10-01

    The no-cloning theorem states that an unknown quantum state cannot be cloned exactly and deterministically due to the linearity of quantum mechanics. Associated with this theorem is the quantitative no-cloning limit that sets an upper bound to the quality of the generated clones. However, this limit can be circumvented by abandoning determinism and using probabilistic methods. Here, we report an experimental demonstration of probabilistic cloning of arbitrary coherent states that clearly surpasses the no-cloning limit. Our scheme is based on a hybrid linear amplifier that combines an ideal deterministic linear amplifier with a heralded measurement-based noiseless amplifier. We demonstrate the production of up to five clones with the fidelity of each clone clearly exceeding the corresponding no-cloning limit. Moreover, since successful cloning events are heralded, our scheme has the potential to be adopted in quantum repeater, teleportation and computing applications.

  19. Development of an intense positron source using a crystal--amorphous hybrid target for linear colliders

    CERN Document Server

    Uesugi, Y; Chehab, R; Dadoun, O; Furukawa, K; Kamitani, T; Kawada, S; Omori, T; Takahashi, T; Umemori, K; Urakawa, U; Satoh, M; Strakhovenko, V; Suwada, T; Variola, A

    2013-01-01

    In a conventional positron source driven by a few GeV electron beam, a high amount of heat is loaded into a positron converter target to generate intense positrons required by linear colliders, and which would eventually damage the converter target. A hybrid target, composed of a single crystal target as a radiator of intense gamma--rays, and an amorphous converter target placed downstream of the crystal, was proposed as a scheme which could overcome the problem.This paper describes the development of an intense positron source with the hybrid target. A series of experiments on positron generation with the hybrid target has been carried out with a 8--GeV electron beam at the KEKB linac. We observed that positron yield from the hybrid target increased when the incident electron beam was aligned to the crystal axis and exceeded the one from the conventional target with the converter target of the same thickness, when its thickness is less than about 2 radiation length. The measurements in the temperature rise o...

  20. Analysis, control and optimal operations in hybrid power systems advanced techniques and applications for linear and nonlinear systems

    CERN Document Server

    Bizon, Nicu; Mahdavi Tabatabaei, Naser

    2014-01-01

    This book explains and analyzes the dynamic performance of linear and nonlinear systems, particularly for Power Systems including Hybrid Power Sources. Offers a detailed description of system stability using state space energy conservation principle, and more.

  1. 离子色谱-串联质谱法分析环境水体中痕量人工甜味剂%An Innovative Approach to Sensitive Artificial Sweeteners Analysis by Ion Chromatography-Triple Quadrupole Mass Spectrometry

    Institute of Scientific and Technical Information of China (English)

    桂建业; 孙威; 张辰凌; 张永涛; 张莉; 刘菲

    2016-01-01

    Artificial sweeteners ( ASs ) have gained more and more attention by environmental scientists because some of them such as acesulfame, have the potential to be the ideal tracers of domestic wastewater for environmental monitoring. In contrast to the existing methods of artificial sweeteners, the analytical method of ASs as a new tracer for environmental samples requires better sensitivity and selectivity to avoid matrix interference. A highly sensitive method for the simultaneous determination of four frequently-used artificial sweeteners in water samples using solid-phase extraction and ion chromatography triple quadrupole mass spectrometer with an electrospray ionization source ( IC-MS/MS) in negative ion mode was developed. The separation effect of different separation columns was compared and a 2-mm ion chromatography column AS19 was chosen in the experiment. Chromatographic separation of all the 4 artificial sweeteners was carried out in 9 min in isocratic elution mode using 60 mmol/L sodium hydroxide as eluent. Different kinds of solid phase extraction cartridges were evaluated to obtain satisfactory recoveries of all of the analytes. Merk LiChrolut EN (200 mg, 3 mL) was preconditioned with 2 mL of methanol, followed by 2 mL of H2 O. About 200 mL of sample (pH<2. 0) was passed through the cartridge at a flow rate of 4 mL/min, and then the cartridge was eluted using 2 mL of methanol. 2 mm suppresser (75 mA) was used to reduce the background noise and to remove the matrix interference. The limits of detection were below 5. 0 ng/L for various artificial sweeteners based on 3-fold the S/N. The recoveries of different matrices in the samples were 65%-120%. The method described here is time-saving, accurate and precise, and is suitable for monitoring artificial sweeteners in different water matrices. The method has also the potential to trace other contaminants in groundwater.%人工甜味剂被广泛使用并且在环境中持久存在,因此可能成为生活

  2. A LINEAR HYBRID MODEL OF MSE AND BEM FOR FLOATING STRUCTURES IN COASTAL ZONES

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun; MIAO Guo-ping

    2006-01-01

    A linear hybrid model of Mild Slope Equation (MSE) and Boundary Element Method (BEM) is developed to study the wave propagation around floating structures in coastal zones. Both the wave refraction under the influence of topography and the wave diffraction by floating structures are considered. Hence, the model provides wave properties around the coastal floating structures of arbitrary shape but also the wave forces on and the hydrodynamic characteristics of the structures. Different approaches are compared to demonstrate the validity of the present hybrid model. Several numerical tests are carried out for the cases of pontoons under different circumstances. The results show that the influence of topography on the hydrodynamic characteristics of floating structures in coastal regions is important and must not be ignored in the most wave period range with practical interests.

  3. Design and property analysis of a hybrid linear actuator based on shape memory alloy

    Science.gov (United States)

    Zhang, Xiaoguang; Hu, Jinhong; Mao, Shixin; Dong, Erbao; Yang, Jie

    2014-12-01

    This paper introduces two methods for solving two bottlelike problems regarding the shape memory alloy (SMA) application as actuators. These methods are ‘rotating output,’ which aims to solve the problem of the low working frequency caused by the demand for cool time, and ‘accumulated shifting,’ which solves the problem of difficult-to-obtain output displacements in a large scale. We also introduce a hybrid linear actuator that applies the two methods and achieves both a strong force and an accurate large output displacement while working at a high frequency based on the SMA wires and DC motors. A prototype of this actuator was fabricated and tested to verify the two methods. This hybrid actuator system dynamic model, which was composed of the constitutive model of the SMA, the electrical and heat transfer behavior of the SMA wires and the dynamics of the linear actuation system, was established and discussed. Our study aims to illuminate the application of an SMA in actuators with the proposed methods with regard to its two main problems. An actuator with a high power-weight ratio and the capability to work at a high frequency, as well as accurate linear step displacements in a large scale, is also presented.

  4. Hybrid state-space self-tuning control of uncertain linear systems

    Science.gov (United States)

    Shieh, L. S.; Wang, Y. J.; Sunkel, J. W.

    1993-01-01

    The paper presents a hybrid state-space self-tuner using a new dual-rate sampling scheme for digital adaptive control of continuous-time uncertain linear systems. A state-space-based recursive least-squares algorithm, together with a variable forgetting factor, is used for direct estimations of both the equivalent discrete-time uncertain linear system parameters and the associated discrete-time state of a continuous-time uncertain linear system from the sampled input and output data. An analogue optimal regional pole-placement design method is used for designing an optimal observer-based analogue controller. A suboptimal observer-based digital controller is then designed from the designed analogue controller using digital redesign technique. To enhance the robustness of parameter identification and state estimation algorithms, a dynamic bound for a class of uncertain bilinear parameters and a fast-rate digital controller are developed at each fast-sampling period. Also, to accommodate computation loads and computation delay for developing the advanced hybrid self-tuner, the designed analogue controller and observer gains are both updated at each slow-sampling period. This control technique has been successfully applied to benchmark control problems.

  5. A hybrid-stress solid-shell element for non-linear analysis of piezoelectric structures

    Institute of Scientific and Technical Information of China (English)

    SZE; K; Y

    2009-01-01

    This paper presents eight-node solid-shell elements for geometric non-linear analyze of piezoelectric structures. To subdue shear, trapezoidal and thickness locking, the assumed natural strain method and an ad hoc modified generalized laminate stiffness matrix are employed. With the generalized stresses arising from the modified generalized laminate stiffness matrix assumed to be independent from the ones obtained from the displacement, an extended Hellinger-Reissner functional can be derived. By choosing the assumed generalized stresses similar to the assumed stresses of a previous solid ele- ment, a hybrid-stress solid-shell element is formulated. The presented finite shell element is able to model arbitrary curved shell structures. Non-linear numerical examples demonstrate the ability of the proposed model to analyze nonlinear piezoelectric devices.

  6. Extraction of linear anisotropic parameters using optical coherence tomography and hybrid Mueller matrix formalism.

    Science.gov (United States)

    Liao, Chia-Chi; Lo, Yu-Lung

    2015-04-20

    A method is proposed for extracting the linear birefringence (LB) and linear dichroism (LD) properties of an anisotropic optical sample using reflection-mode optical coherence tomography (OCT) and a hybrid Mueller matrix formalism. To ensure the accuracy of the extracted parameter values, a method is proposed for calibrating and compensating the polarization distortion effect induced by the beam splitters in the OCT system using a composite quarter-waveplate / half-waveplate / quarter-waveplate structure. The validity of the proposed method is confirmed by extracting the LB and LD properties of a quarter-wave plate and a defective polarizer. To the best of the authors' knowledge, the method proposed in this study represents the first reported attempt to utilize an inverse Mueller matrix formalism and a reflection-mode OCT structure to extract the LB and LD parameters of optically anisotropic samples.

  7. State estimation of stochastic non-linear hybrid dynamic system using an interacting multiple model algorithm.

    Science.gov (United States)

    Elenchezhiyan, M; Prakash, J

    2015-09-01

    In this work, state estimation schemes for non-linear hybrid dynamic systems subjected to stochastic state disturbances and random errors in measurements using interacting multiple-model (IMM) algorithms are formulated. In order to compute both discrete modes and continuous state estimates of a hybrid dynamic system either an IMM extended Kalman filter (IMM-EKF) or an IMM based derivative-free Kalman filters is proposed in this study. The efficacy of the proposed IMM based state estimation schemes is demonstrated by conducting Monte-Carlo simulation studies on the two-tank hybrid system and switched non-isothermal continuous stirred tank reactor system. Extensive simulation studies reveal that the proposed IMM based state estimation schemes are able to generate fairly accurate continuous state estimates and discrete modes. In the presence and absence of sensor bias, the simulation studies reveal that the proposed IMM unscented Kalman filter (IMM-UKF) based simultaneous state and parameter estimation scheme outperforms multiple-model UKF (MM-UKF) based simultaneous state and parameter estimation scheme.

  8. A Neural Network Based Hybrid Mixture Model to Extract Information from Non-linear Mixed Pixels

    Directory of Open Access Journals (Sweden)

    Uttam Kumar

    2012-09-01

    Full Text Available Signals acquired by sensors in the real world are non-linear combinations, requiring non-linear mixture models to describe the resultant mixture spectra for the endmember’s (pure pixel’s distribution. This communication discusses inferring class fraction through a novel hybrid mixture model (HMM. HMM is a three-step process, where the endmembers are first derived from the images themselves using the N-FINDR algorithm. These endmembers are used by the linear mixture model (LMM in the second step that provides an abundance estimation in a linear fashion. Finally, the abundance values along with the training samples representing the actual ground proportions are fed into neural network based multi-layer perceptron (MLP architecture as input to train the neurons. The neural output further refines the abundance estimates to account for the non-linear nature of the mixing classes of interest. HMM is first implemented and validated on simulated hyper spectral data of 200 bands and subsequently on real time MODIS data with a spatial resolution of 250 m. The results on computer simulated data show that the method gives acceptable results for unmixing pixels with an overall RMSE of 0.0089 ± 0.0022 with LMM and 0.0030 ± 0.0001 with the HMM when compared to actual class proportions. The unmixed MODIS images showed overall RMSE with HMM as 0.0191 ± 0.022 as compared to the LMM output considered alone that had an overall RMSE of 0.2005 ± 0.41, indicating that individual class abundances obtained from HMM are very close to the real observations.

  9. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Directory of Open Access Journals (Sweden)

    Yi Sui

    2017-05-01

    Full Text Available A single-phase tubular permanent-magnet linear machine (PMLM with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA. The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  10. A tubular hybrid Halbach/axially-magnetized permanent-magnet linear machine

    Science.gov (United States)

    Sui, Yi; Liu, Yong; Cheng, Luming; Liu, Jiaqi; Zheng, Ping

    2017-05-01

    A single-phase tubular permanent-magnet linear machine (PMLM) with hybrid Halbach/axially-magnetized PM arrays is proposed for free-piston Stirling power generation system. Machine topology and operating principle are elaborately illustrated. With the sinusoidal speed characteristic of the free-piston Stirling engine considered, the proposed machine is designed and calculated by finite-element analysis (FEA). The main structural parameters, such as outer radius of the mover, radial length of both the axially-magnetized PMs and ferromagnetic poles, axial length of both the middle and end radially-magnetized PMs, etc., are optimized to improve both the force capability and power density. Compared with the conventional PMLMs, the proposed machine features high mass and volume power density, and has the advantages of simple control and low converter cost. The proposed machine topology is applicable to tubular PMLMs with any phases.

  11. A high temperature hybrid photovoltaic-thermal receiver employing spectral beam splitting for linear solar concentrators

    Science.gov (United States)

    Mojiri, Ahmad; Stanley, Cameron; Rosengarten, Gary

    2015-09-01

    Hybrid photovoltaic/thermal (PV-T) solar collectors are capable of delivering heat and electricity concurrently. Implementing such receivers in linear concentrators for high temperature applications need special considerations such as thermal decoupling of the photovoltaic (pv) cells from the thermal receiver. Spectral beam splitting of concentrated light provides an option for achieving this purpose. In this paper we introduce a relatively simple hybrid receiver configuration that spectrally splits the light between a high temperature thermal fluid and silicon pv cells using volumetric light filtering by semi-conductor doped glass and propylene glycol. We analysed the optical performance of this device theoretically using ray tracing and experimentally through the construction and testing of a full scale prototype. The receiver was mounted on a commercial parabolic trough concentrator in an outdoor experiment. The prototype receiver delivered heat and electricity at total thermal efficiency of 44% and electrical efficiency of 3.9% measured relative to the total beam energy incident on the primary mirror.

  12. Quasi-linear modeling of lower hybrid current drive in ITER and DEMO

    Energy Technology Data Exchange (ETDEWEB)

    Cardinali, A., E-mail: alessandro.cardinali@enea.it; Cesario, R.; Panaccione, L.; Santini, F.; Amicucci, L.; Castaldo, C.; Ceccuzzi, S.; Mirizzi, F.; Tuccillo, A. A. [ENEA, Unità Tecnica Fusione, Via E Fermi 45 Rome (Italy)

    2015-12-10

    First pass absorption of the Lower Hybrid waves in thermonuclear devices like ITER and DEMO is modeled by coupling the ray tracing equations with the quasi-linear evolution of the electron distribution function in 2D velocity space. As usually assumed, the Lower Hybrid Current Drive is not effective in a plasma of a tokamak fusion reactor, owing to the accessibility condition which, depending on the density, restricts the parallel wavenumber to values greater than n{sub ∥crit} and, at the same time, to the high electron temperature that would enhance the wave absorption and then restricts the RF power deposition to the very periphery of the plasma column (near the separatrix). In this work, by extensively using the “ray{sup star}” code, a parametric study of the propagation and absorption of the LH wave as function of the coupled wave spectrum (as its width, and peak value), has been performed very accurately. Such a careful investigation aims at controlling the power deposition layer possibly in the external half radius of the plasma, thus providing a valuable aid to the solution of how to control the plasma current profile in a toroidal magnetic configuration, and how to help the suppression of MHD mode that can develop in the outer part of the plasma. This analysis is useful not only for exploring the possibility of profile control of a pulsed operation reactor as well as the tearing mode stabilization, but also in order to reconsider the feasibility of steady state regime for DEMO.

  13. 超声辅助低密度溶剂分散液液微萃取-气相色谱-三重四极杆质谱法检测生物样品中的8种毒品%Ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction for the determination of eight drugs in biological samples by gas chromatography-triple quadrupole mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    孟梁; 朱彬玲; 郑可芳; 张文文; 孟品佳

    2015-01-01

    A novel microextraction technique based on ultrasound-assisted low-density solvent dispersive liquid-liquid microextraction( UA-LDS-DLLME)has been developed for the determi-nation of multiple drugs of abuse in biological samples by gas chromatography-triple quadrupole mass spectrometry( GC-QQQ-MS). A total of 100 μL of toluene as extraction solvent was dropped into the sample solution. Then the mixture was sonicated drastically in an ultrasonic bath for 3 min with occasional manual shaking to form a cloudy suspension. After centrifugation at 10 000 r/min for 3 min,the upper layer of low-density extractant was withdrawn and injected into the GC-QQQ-MS for analysis. The parameters affecting extraction efficiency have been investigated and optimized. Under the optimum conditions,good linearities were observed for all analytes with the correlation coefficients ranging from 0. 998 4 to 0. 999 4. The recoveries of 79. 3%—100. 3% with RSDs<5. 7% were obtained. The LODs( S/N=3)were in the range from 0. 05 to 0. 40 μg/L. UA-LDS-DLLME technique has the advantages of less extraction time,suit-able for batches of sample pretreatment simultaneously,and higher extraction efficiency. It was successfully applied to the analysis of amphetamines in real human urine samples.%建立了生物样品中8种毒品的超声辅助分散液液微萃取-气相色谱-三重四极杆串联质谱检测方法,采用密度比水低的有机溶剂甲苯作为萃取溶剂,萃取过程中不需要任何分散剂。对影响萃取富集效率的因素进行优化:将100μL甲苯萃取剂加入到1 mL样品溶液中,超声波剧烈振荡使甲苯充分分散到样品溶液中进行萃取,离心分层后,抽取上层萃取剂供气相色谱-三重四极杆串联质谱分析检测。在优化条件下,分析物在各自的线性范围内具有良好的线性关系,线性相关系数在0.9984~0.9994之间;检出限为0.05~0.40μg/L( S/N=3);样品加标回收率在79.3

  14. Rapid determination of ¹³⁵Cs and precise ¹³⁵Cs/¹³⁷Cs atomic ratio in environmental samples by single-column chromatography coupled to triple-quadrupole inductively coupled plasma-mass spectrometry.

    Science.gov (United States)

    Yang, Guosheng; Tazoe, Hirofumi; Yamada, Masatoshi

    2016-02-18

    For source identification, measurement of (135)Cs/(137)Cs atomic ratio not only provides information apart from the detection of (134)Cs and (137)Cs, but it can also overcome the application limit that measurement of the (134)Cs/(137)Cs ratio has due to the short half-life of (134)Cs (2.06 y). With the recent advancement of ICP-MS, it is necessary to improve the corresponding separation method for rapid and precise (135)Cs/(137)Cs atomic ratio analysis. A novel separation and purification technique was developed for the new generation of triple-quadrupole inductively coupled plasma-mass spectrometry (ICP-MS/MS). The simple chemical separation, incorporating ammonium molybdophosphate selective adsorption of Cs and subsequent single cation-exchange chromatography, removes the majority of isobaric and polyatomic interference elements. Subsequently, the ICP-MS/MS removes residual interference elements and eliminates the peak tailing effect of stable (133)Cs, at m/z 134, 135, and 137. The developed analytical method was successfully applied to measure (135)Cs/(137)Cs atomic ratios and (135)Cs activities in environmental samples (soil and sediment) for radiocesium source identification.

  15. Optimal Design of Stochastic Distributed Order Linear SISO Systems Using Hybrid Spectral Method

    Directory of Open Access Journals (Sweden)

    Pham Luu Trung Duong

    2015-01-01

    Full Text Available The distributed order concept, which is a parallel connection of fractional order integrals and derivatives taken to the infinitesimal limit in delta order, has been the main focus in many engineering areas recently. On the other hand, there are few numerical methods available for analyzing distributed order systems, particularly under stochastic forcing. This paper proposes a novel numerical scheme for analyzing the behavior of a distributed order linear single input single output control system under random forcing. The method is based on the operational matrix technique to handle stochastic distributed order systems. The existing Monte Carlo, polynomial chaos, and frequency methods were first adapted to the stochastic distributed order system for comparison. Numerical examples were used to illustrate the accuracy and computational efficiency of the proposed method for the analysis of stochastic distributed order systems. The stability of the systems under stochastic perturbations can also be inferred easily from the moment of random output obtained using the proposed method. Based on the hybrid spectral framework, the optimal design was elaborated on by minimizing the suitably defined constrained-optimization problem.

  16. Dynamical Linear Response of TDDFT with LDA+U Functional: Strongly Hybridized Frenkel Excitons in NiO

    Energy Technology Data Exchange (ETDEWEB)

    Lee, C.C.; Ku, W.; Hsueh, H.C.

    2010-08-30

    Within the framework of time-dependent density-functional theory (TDDFT), we derive the dynamical linear response of local-density approximation plus U functional and benchmark it on NiO, a prototypical Mott insulator. Formulated using real-space Wannier functions, our computationally inexpensive framework gives detailed insights into the formation of tightly bound Frenkel excitons with reasonable accuracy. Specifically, a strong hybridization of multiple excitons is found to significantly modify the exciton properties. Furthermore, our study exposes a significant generic limitation of adiabatic approximation in TDDFT with hybrid functionals and in existing Bethe-Salpeter-equation approaches, advocating the necessity of strongly energy-dependent kernels in future development.

  17. Development of hybrid gas detectors for monitoring neutrons induced from the large intensity proton linear Accelerator

    Energy Technology Data Exchange (ETDEWEB)

    Shim, G. S.; Lee, G. S.; Ahn, S. H. [Korea Univ., Seoul (Korea, Republic of)

    2005-05-15

    Design of a hybrid gaseous detector for slow neutrons. Construction of the hybrid gaseous detector and tests with a {sup 52}Cf isotope and the MC-50 cyclotron. Designs, constructions, and tests for hybrid scintillators using various neutron sensitive materials (2{sup nd} year). Application to development of detectors for high energy physics (2{sup nd} year). Practical R and Ds for applications to medical and industrial purposes (3{sup rd} year)

  18. Total synthesis of feglymycin based on a linear/convergent hybrid approach using micro-flow amide bond formation

    Science.gov (United States)

    Fuse, Shinichiro; Mifune, Yuto; Nakamura, Hiroyuki; Tanaka, Hiroshi

    2016-11-01

    Feglymycin is a naturally occurring, anti-HIV and antimicrobial 13-mer peptide that includes highly racemizable 3,5-dihydroxyphenylglycines (Dpgs). Here we describe the total synthesis of feglymycin based on a linear/convergent hybrid approach. Our originally developed micro-flow amide bond formation enabled highly racemizable peptide chain elongation based on a linear approach that was previously considered impossible. Our developed approach will enable the practical preparation of biologically active oligopeptides that contain highly racemizable amino acids, which are attractive drug candidates.

  19. Hybrid Estimation of State and Input for Linear Continuous Time-varying Systems: A Game Theory Approach

    Institute of Scientific and Technical Information of China (English)

    YANGXiao-Jun; WENGZheng-Xin; TIANZuo-Hua; SHISong-Jiao

    2005-01-01

    The H∞ hybrid estimation problem for linear continuous time-varying systems is investigated in this paper, where estimated signals are linear combination of state and input. Design objective requires the worst-case energy gain from disturbance to estimation error be less than a prescribed level. Optimal solution of the hybrid estimation problem is the saddle point of a two-player zero sum differential game. Based on the differential game approach, necessary and sufficient solvable conditions for the hybrid estimation problem are provided in terms of solutions to a Riccati differential equation. Moreover, one possible estimator is proposed if the solvable conditions are satisfied.The estimator is characterized by a gain matrix and an output mapping matrix that reflects the internal relations between the unknown input and output estimation error. Both state and unknown inputs estimation are realized by the proposed estimator. Thus, the results in this paper are also capable of dealing with fault diagnosis problems of linear time-varying systems. At last, a numerical example is provided to illustrate the proposed approach.

  20. Comparison of two ionic liquid dispersive liquid-liquid microextraction approaches for the determination of benzoylurea insecticides in wastewater using liquid chromatography-quadrupole-linear ion trap-mass spectrometry: evaluation of green parameters.

    Science.gov (United States)

    Vázquez, M M Parrilla; Vázquez, P Parrilla; Galera, M Martínez; Moreno, A Uclés

    2014-08-22

    Two dispersive liquid-liquid microextraction (DLLME) approaches including temperature-controlled ionic liquid dispersive liquid-liquid microextraction (TCIL-DLLME) and ultrasound-assisted ionic liquid dispersive liquid-liquid microextraction (US-IL-DLLME) were compared for the extraction of six benzoylurea insecticides (diflubenzuron, triflumuron, hexaflumuron, teflubenzuron, lufenuron and flufenoxuron) from wastewater samples prior to their determination by high-performance liquid chromatography with a hybrid triple quadrupole-linear ion trap-mass spectrometer (LC-QqLIT-MS/MS). Influential parameters affecting extraction efficiency were systematically studied and optimized and the most significant green parameters were quantified and compared. The best results were obtained using the US-IL-DLLME procedure, which employed the IL 1-octyl-3-methylimidazolium hexafluorophosphate ([C8MIM][PF6]) and methanol (MeOH) as extraction and disperser solvent, respectively. US-IL-DLLME procedure was fast, easy, low environmental toxicity and, it was also able to successfully extract all selected benzoylureas. This method was extensively validated with satisfactory results: limits of detection and quantification were in the range 0.5-1.0 ng L(-1) and 1.5-3.5 ng L(-1), respectively, whereas recovery rates ranged from 89 to 103% and the relative standard deviations were lower than 13.4%. The applicability of the method was assessed with the analysis of effluent wastewater samples from a wastewater treatment plant located in an agricultural zone of Almería (Spain) and the results indicated the presence of teflubenzuron at mean concentration levels of 11.3 ng L(-1). US-IL-DLLME sample treatment in combination with LC-QqLIT-MS/MS has demonstrated to be a sensitive, selective and efficient method to determine benzoylurea insecticides in wastewaters at ultra-trace levels.

  1. Anionic linear-globular dendrimers: biocompatible hybrid materials with potential uses in nanomedicine.

    Science.gov (United States)

    Alavidjeh, Mohammad Shafiee; Haririan, Ismaeil; Khorramizadeh, Mohammad Reza; Ghane, Zohre Zarei; Ardestani, Mehdi Shafiee; Namazi, Hassan

    2010-04-01

    The use of dendrimers as nano-sized excipients/vectors in biological and pharmaceutical systems is dependent on the investigation of their toxicological profiles in biological media. In this study, a series of mechanistic in vitro structure-associated cell toxicity evaluations was performed on the two generations of an anionic linear-globular dendrimer G1 and G2 (where PEG is the core, and citric acid is the periphery) each of which has a different size, charge, and MW. In vitro cytotoxicity behavior of the dendrimers with the methods like crystal violet staining, methyl thiazolyl tetrazolium (MTT), and lactate dehydrogenase (LDH) assays was analyzed. The cell death mechanisms (apoptosis-necrosis) induced by the dendrimers were also evaluated in HT1080 cell line. The impact of the dendrimers on the release of the pro-inflammatory cytokines like TNF-alpha (tumor necrosis factor alpha) and IL1-beta (interleukin 1 beta) was assessed in THP-1 cell line. Hemolysis assay and coagulation studies such as PT (prothrombin time) and APTT (activated partial thromboplastin time) on human blood samples were conducted to examine the interactions of the dendrimers with such bio-environments. The results of cell cytotoxicity experiments and the amounts of IL1-beta and TNF-alpha secretions from THP-1 cell line were consistent with the hemoglobin release from the erythrocytes and the results gained from the coagulation studies. In fact, no significant harmful effect was observed for the dendrimers up to the concentration of 0.5 mg/ml. Both apoptosis and necrosis were ascribed to cell death. The G1 with more flexibility, less negative charge, and greater poly dispersity in size versus the G2 displayed more toxicity than the G2 at the concentration of 1 mg/ml and above in most of the experiments. As a whole, these results suggest a biocompatible range for these hybrid structures up to the concentration of 0.5 mg/ml. Therefore, the potentiality for these structures to be employed in the

  2. Optimisation Sizing of Hybrid Wind-Diesel Systems using Linear Programming Technique

    OpenAIRE

    Gan, Leong Kit; Shek, Jonathan; Mueller, Markus

    2014-01-01

    Despite the great potential of hybrid wind-diesel system in supplying energy to remote or island communities, sizing the system components have been a challenging problem for many project managers due to the reliance on various factors. This work considers utilising a fixed speed wind turbine (induction generator) in the hybrid system. It requires energy for start-up operation and this work takes into account for sizing the battery storage. In addition, the trade-off between the number of bat...

  3. Semiconductor-metal nanoparticle molecules: hybrid excitons and non-linear Fano effect

    OpenAIRE

    Zhang, Wei; Govorov, Alexander O.; Bryant, Garnett W.

    2006-01-01

    Modern nanotechnology opens the possibility of combining nanocrystals of various materials with very different characteristics in one superstructure. The resultant superstructure may provide new physical properties not encountered in homogeneous systems. Here we study theoretically the optical properties of hybrid molecules composed of semiconductor and metal nanoparticles. Excitons and plasmons in such a hybrid molecule become strongly coupled and demonstrate novel properties. At low inciden...

  4. One step derivatization with British Anti-Lewsite in combination with gas chromatography coupled to triple-quadrupole tandem mass spectrometry for the fast and selective analysis of inorganic arsenic in rice.

    Science.gov (United States)

    Kang, Ju Hui; Jung, Hyun Jeong; Jung, Mun Yhung

    2016-08-31

    We developed a new fast and selective analytical method for the determination of inorganic arsenic (iAs) in rice by a gas chromatography - tandem mass spectrometry (GC-MS/MS) in combination with one step derivatization of inorganic arsenic (iAs) with British Anti-Lewsite (BAL). Two step derivatization of iAs with BAL has been previously performed for the GC-MS analysis. In this paper, the quantitative one step derivatization condition was successfully established. The GC-MS/MS was carried out with a short nonpolar capillary column (0.25 mm × 10 m) under the conditions of fast oven temperature ramp rate (4 °C/s) and high linear velocity (108.8 cm/s) of the carrier gas. The established GC-MS/MS method showed an excellent linearity (r(2) > 0.999) in a tested range (0.2-100.0 μg L(-1)), ultra-low limit of detection (LOD, 0.08 pg), and high precision and accuracy. The GC-MS/MS technique showed far greater selectivity (22.5 fold higher signal to noise ratio in rice sample) on iAs than GC-MS method. The gas chromatographic running time was only 2.5 min with the iAs retention time of 1.98 min. The established method was successfully applied to quantify the iAs contents in polished rice. The mean iAs content in the Korean polished rice (n = 27) was 66.1 μg kg(-1) with the range of 37.5-125.0 μg kg(-1). This represents the first report on the GC-tandem mass spectrometry in combination with the one step derivatization with BAL for the iAs speciation in rice. This GC-MS/MS method would be a simple, useful and reliable measure for the iAs analysis in rice in the laboratories in which the expensive and element specific HPLC-ICP-MS is not available.

  5. [QuEChERS-based extraction procedure and rapid resolution liquid chromatography coupled to triple quadrupole mass spectrometry for the determination of nine mycotoxins in cereal-based complementary foods for infants and young children].

    Science.gov (United States)

    Hu, Wenyan; Xu, Lei; Yang, Jun; Ling, Rui

    2014-02-01

    A rapid method has been developed for the determination of aflatoxins B1, B2, G1 and G2, ochratoxin A, zearalenone, T-2 toxin, deoxynivalenol and fumonisin B1 in cereal-based complementary foods for infants and young children. The mycotoxins were extracted from the samples using a modified QuEChERS-based extraction procedure without any further clean-up step. The separation of the analytes was carried out on an Agilent XDB C18 column (50 mm x 2.1 mm, 1.8 microm) using the mobile phases of acetonitrile and 5 mmol/L ammonium acetate-0.1% (volume percentage) formic acid aqueous solution with gradient elution. The extract was determined by rapid resolution liquid chromatography-tandem mass spectrometry. Matrix-matched calibration was used for the quantification. The proposed method showed good linear correlation with the correlation coefficients all above 0.98. The blank samples were fortified at three levels, and the recoveries ranged from 77.6% to 105.7% with the RSDs from 2.5% to 13.7%. The limits of detection ranged from 0.1 microg/kg to 15.8 microg/kg. The developed method was successfully applied for mycotoxin analysis in 41 samples bought from markets. The method shows advantages in both accuracy and sensitivity, and is suitable for the rapid multi-aflatoxin screening in cereal-based complementary foods for infants and young children.

  6. Hybrid System Modeling and Full Cycle Operation Analysis of a Two-Stroke Free-Piston Linear Generator

    Directory of Open Access Journals (Sweden)

    Peng Sun

    2017-02-01

    Full Text Available Free-piston linear generators (FPLGs have attractive application prospects for hybrid electric vehicles (HEVs owing to their high-efficiency, low-emissions and multi-fuel flexibility. In order to achieve long-term stable operation, the hybrid system design and full-cycle operation strategy are essential factors that should be considered. A 25 kW FPLG consisting of an internal combustion engine (ICE, a linear electric machine (LEM and a gas spring (GS is designed. To improve the power density and generating efficiency, the LEM is assembled with two modular flat-type double-sided PM LEM units, which sandwich a common moving-magnet plate supported by a middle keel beam and bilateral slide guide rails to enhance the stiffness of the moving plate. For the convenience of operation processes analysis, the coupling hybrid system is modeled mathematically and a full cycle simulation model is established. Top-level systemic control strategies including the starting, stable operating, fault recovering and stopping strategies are analyzed and discussed. The analysis results validate that the system can run stably and robustly with the proposed full cycle operation strategy. The effective electric output power can reach 26.36 kW with an overall system efficiency of 36.32%.

  7. Efficient modeling of plasma wakefield acceleration in quasi-non-linear-regimes with the hybrid code Architect

    Science.gov (United States)

    Marocchino, A.; Massimo, F.; Rossi, A. R.; Chiadroni, E.; Ferrario, M.

    2016-09-01

    In this paper we present a hybrid approach aiming to assess feasible plasma wakefield acceleration working points with reduced computation resources. The growing interest for plasma wakefield acceleration and especially the need to control with increasing precision the quality of the accelerated bunch demands for more accurate and faster simulations. Particle in cell codes are the state of the art technique to simulate the underlying physics, however the run-time represents the major drawback. Architect is a hybrid code that treats the bunch kinetically and the background electron plasma as a fluid, initialising bunches in vacuum so to take into account for the transition from vacuum to plasma. Architect solves directly the Maxwell's equations on a Yee lattice. Such an approach allows us to drastically reduce run time without loss of generality or accuracy up to the weakly non linear regime.

  8. Efficient modeling of plasma wakefield acceleration in quasi-non-linear-regimes with the hybrid code Architect

    Energy Technology Data Exchange (ETDEWEB)

    Marocchino, A., E-mail: albz.uk@gmail.com [Dipartimento SBAI, “Sapienza” University of Rome and INFN-Roma 1, Rome (Italy); Massimo, F. [Dipartimento SBAI, “Sapienza” University of Rome and INFN-Roma 1, Rome (Italy); Rossi, A.R. [Dipartimento di Fisica, University of Milan and INFN-Milano, Milano (Italy); Chiadroni, E.; Ferrario, M. [INFN-LNF, Frascati (Italy)

    2016-09-01

    In this paper we present a hybrid approach aiming to assess feasible plasma wakefield acceleration working points with reduced computation resources. The growing interest for plasma wakefield acceleration and especially the need to control with increasing precision the quality of the accelerated bunch demands for more accurate and faster simulations. Particle in cell codes are the state of the art technique to simulate the underlying physics, however the run-time represents the major drawback. Architect is a hybrid code that treats the bunch kinetically and the background electron plasma as a fluid, initialising bunches in vacuum so to take into account for the transition from vacuum to plasma. Architect solves directly the Maxwell's equations on a Yee lattice. Such an approach allows us to drastically reduce run time without loss of generality or accuracy up to the weakly non linear regime.

  9. A novel methodology for non-linear system identification of battery cells used in non-road hybrid electric vehicles

    Science.gov (United States)

    Unger, Johannes; Hametner, Christoph; Jakubek, Stefan; Quasthoff, Marcus

    2014-12-01

    An accurate state of charge (SoC) estimation of a traction battery in hybrid electric non-road vehicles, which possess higher dynamics and power densities than on-road vehicles, requires a precise battery cell terminal voltage model. This paper presents a novel methodology for non-linear system identification of battery cells to obtain precise battery models. The methodology comprises the architecture of local model networks (LMN) and optimal model based design of experiments (DoE). Three main novelties are proposed: 1) Optimal model based DoE, which aims to high dynamically excite the battery cells at load ranges frequently used in operation. 2) The integration of corresponding inputs in the LMN to regard the non-linearities SoC, relaxation, hysteresis as well as temperature effects. 3) Enhancements to the local linear model tree (LOLIMOT) construction algorithm, to achieve a physical appropriate interpretation of the LMN. The framework is applicable for different battery cell chemistries and different temperatures, and is real time capable, which is shown on an industrial PC. The accuracy of the obtained non-linear battery model is demonstrated on cells with different chemistries and temperatures. The results show significant improvement due to optimal experiment design and integration of the battery non-linearities within the LMN structure.

  10. ε-MAXIMUM PRINCIPLE IN LINEAR PROBLEM OF HYBRID SYSTEM OPTIMUM CONTROL

    Directory of Open Access Journals (Sweden)

    O. R. Gabasova

    2009-01-01

    Full Text Available The paper reveals necessary and sufficient conditions of optimality and sub-optimality of the programs for a hybrid system in the class of discrete control actions. The conditions are formulated in the support terms of  the initial problem. 

  11. Ultraprecision XY stage using a hybrid bolt-clamped Langevin-type ultrasonic linear motor for continuous motion

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Dong-Jin; Lee, Sun-Kyu, E-mail: skyee@gist.ac.kr [School of Mechatronics, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712 (Korea, Republic of)

    2015-01-15

    This paper presents a design and control system for an XY stage driven by an ultrasonic linear motor. In this study, a hybrid bolt-clamped Langevin-type ultrasonic linear motor was manufactured and then operated at the resonance frequency of the third longitudinal and the sixth lateral modes. These two modes were matched through the preload adjustment and precisely tuned by the frequency matching method based on the impedance matching method with consideration of the different moving weights. The XY stage was evaluated in terms of position and circular motion. To achieve both fine and stable motion, the controller consisted of a nominal characteristics trajectory following (NCTF) control for continuous motion, dead zone compensation, and a switching controller based on the different NCTFs for the macro- and micro-dynamics regimes. The experimental results showed that the developed stage enables positioning and continuous motion with nanometer-level accuracy.

  12. Linear and nonlinear optics of hybrid plasmon-exciton nanomaterials in the presence of overlapping resonances

    CERN Document Server

    Sukharev, Maxim; Pachter, Ruth

    2015-01-01

    We consider a hybrid plasmon-exciton system comprised of a resonant molecular subsystem and three Au wires supporting a dipole mode which can be coupled to a dark mode in controllable fashion by variation of a symmetry parameter. The physics of such a system under strong coupling conditions is examined in detail. It is shown that if two wires supporting the dark mode are covered with molecular layers the system exhibits four resonant modes for a strong coupling regime due to asymmetry and lifted degeneracy of the molecular state in this case, while upon having molecular aggregates covering the top wire with dipolar mode, three resonant modes appear. Pump-probe simulations are performed to scrutinize the quantum dynamics and find possible ways to control plasmon-exciton materials. It is demonstrated that one can design hybrid nanomaterials with highly pronounced Fano-type resonances when excited by femtosecond lasers.

  13. A LINEAR-NEURAL HYBRID MODEL FOR ANALYSIS AND FORECASTING OF TIME-SERIES

    OpenAIRE

    MARCELO CUNHA MEDEIROS

    1998-01-01

    Esta dissertação apresenta um modelo não linear auto-regressivo com variáveis exógenas (ARX), para análise e previsão de séries temporais. Os coeficientes do modelo são estimados pela saída de uma rede neural feed-forward, treinada por um algoritmo híbrido de otimização. Os resultados obtidos são comparados tanto com modelos lineares, quanto com não lineares. This thesis presents a non linear autoregressive model with exogeneous variables (ARX), for time series analysis and forecasting. Th...

  14. Studying non-linearity of Mercury magnetosphere and solar wind interaction features using the combined hybrid model

    Science.gov (United States)

    Parunakian, David; Dyadechkin, Sergey; Alexeev, Igor; Belenkaya, Elena; Khodachenko, Maxim; Kallio, Esa; Alho, Markku

    2017-04-01

    The main focus of this work is to investigate non-linearity of Mercury's magnetospheric features. We use the paraboloid magnetospheric model (PMM) to calculate the initial magnetospheric field which we then use in hybrid simulations. We show that the initial total magnetospheric field can be considered a linear combination of the planetary dipole field, magnetospheric current system fields, and a penetrating portion of the interplanetary magnetic field (IMF). We use two sets of modelling runs with IMF values of identical magnitudes and anti-parallel directions. We then compute semi-sums and semi-differences of final magnetic field maps generated by hybrid plasma simulations, and use semi-sums to cancel out IMF contributions and semi-differences to cancel out PMM contributions. The remnant fields outside and inside the magnetosphere (for semi-sum and semi-difference fields, accordingly) are used to improve our ability to determine the position of the bow shock and magnetopause, as well as calculate the IMF penetration coefficient that results into best matches of this model to observational MESSENGER data. We compare Mercury's magnetosheath magnetic field predicted by our model with MESSENGER data in the appropriate orbit sections.

  15. Free chattering hybrid sliding mode control for a class of non-linear systems

    DEFF Research Database (Denmark)

    Khooban, Mohammad-Hassan; Niknam, Taher; Blaabjerg, Frede

    2016-01-01

    In current study, in order to find the control of general uncertain nonlinear systems, a new optimal hybrid control approach called Optimal General Type II Fuzzy Sliding Mode (OGT2FSM) is presented. In order to estimate unknown nonlinear activities in monitoring dynamic uncertainties, the benefits...... on the same topic, which are an Adaptive Interval Type-2 Fuzzy Logic Controller (AGT2FLC) and Conventional Sliding Mode Controller (CSMC), to assess the efficiency of the suggested controller. The suggested control scheme is finally used to the Electric Vehicles type as a case study. Results of simulation...

  16. Mixed-Integer-Linear-Programming-Based Energy Management System for Hybrid PV-Wind-Battery Microgrids

    DEFF Research Database (Denmark)

    Hernández, Adriana Carolina Luna; Aldana, Nelson Leonardo Diaz; Graells, Moises

    2017-01-01

    -side strategy, defined as a general mixed-integer linear programming by taking into account two stages for proper charging of the storage units. This model is considered as a deterministic problem that aims to minimize operating costs and promote self-consumption based on 24-hour ahead forecast data...

  17. Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

    Science.gov (United States)

    Gao, Q. D.; Budny, R. V.

    2015-03-01

    By using gyro-Landau fluid transport model (GLF23), time-dependent integrated modeling is carried out using TRANSP to explore the dynamic process of internal transport barrier (ITB) formation in the neutral beam heating discharges. When the current profile is controlled by LHCD (lower hybrid current drive), with appropriate neutral beam injection, the nonlinear interplay between the transport determined gradients in the plasma temperature (Ti,e) and toroidal velocity (Vϕ) and the E×B flow shear (including q-profile) produces transport bifurcations, generating spontaneously a stepwise growing ITB. In the discharge, the constraints imposed by the wave propagation condition causes interplay of the LH driven current distribution with the plasma configuration modification, which constitutes non-linearity in the LH wave deposition. The non-linear effects cause bifurcation in LHCD, generating two distinct quasi-stationary reversed magnetic shear configurations. The change of current profile during the transition period between the two quasi-stationary states results in increase of the E×B shearing flow arising from toroidal rotation. The turbulence transport suppression by sheared E×B flow during the ITB development is analysed, and the temporal evolution of some parameters characterized the plasma confinement is examined. Ample evidence shows that onset of the ITB development is correlated with the enhancement of E×B shearing rate caused by the bifurcation in LHCD. It is suggested that the ITB triggering is associated with the non-linear effects of the LH power deposition.

  18. Optimal Design of Stochastic Distributed Order Linear SISO Systems Using Hybrid Spectral Method

    OpenAIRE

    2015-01-01

    The distributed order concept, which is a parallel connection of fractional order integrals and derivatives taken to the infinitesimal limit in delta order, has been the main focus in many engineering areas recently. On the other hand, there are few numerical methods available for analyzing distributed order systems, particularly under stochastic forcing. This paper proposes a novel numerical scheme for analyzing the behavior of a distributed order linear single input single output control s...

  19. Optimal design of stochastic distributed order linear SISO systems using hybrid spectral method

    OpenAIRE

    2015-01-01

    The distributed order concept, which is a parallel connection of fractional order integrals and derivatives taken to the infinitesimal limit in delta order, has been the main focus in many engineering areas recently. On the other hand, there are few numerical methods available for analyzing distributed order systems, particularly under stochastic forcing. This paper proposes a novel numerical scheme for analyzing the behavior of a distributed order linear single input single output control sy...

  20. A HYBRID TECHNIQUE FOR PAPR REDUCTION OF OFDM USING DHT PRECODING WITH PIECEWISE LINEAR COMPANDING

    Directory of Open Access Journals (Sweden)

    Thammana Ajay

    2016-06-01

    Full Text Available Orthogonal Frequency Division Multiplexing (OFDM is a fascinating approach for wireless communication applications which require huge amount of data rates. However, OFDM signal suffers from its large Peak-to-Average Power Ratio (PAPR, which results in significant distortion while passing through a nonlinear device, such as a transmitter high power amplifier (HPA. Due to this high PAPR, the complexity of HPA as well as DAC also increases. For the reduction of PAPR in OFDM many techniques are available. Among them companding is an attractive low complexity technique for the OFDM signal’s PAPR reduction. Recently, a piecewise linear companding technique is recommended aiming at minimizing companding distortion. In this paper, a collective piecewise linear companding approach with Discrete Hartley Transform (DHT method is expected to reduce peak-to-average of OFDM to a great extent. Simulation results shows that this new proposed method obtains significant PAPR reduction while maintaining improved performance in the Bit Error Rate (BER and Power Spectral Density (PSD compared to piecewise linear companding method.

  1. Oligo(ethylene glycol)-incorporated hybrid linear alkyl side chains for n-channel polymer semiconductors and their effect on the thin-film crystalline structure.

    Science.gov (United States)

    Kim, Ran; Kang, Boseok; Sin, Dong Hun; Choi, Hyun Ho; Kwon, Soon-Ki; Kim, Yun-Hi; Cho, Kilwon

    2015-01-28

    Oligo(ethylene glycol)-incorporated hybrid linear alkyl side chains, serving as solubilizing groups, are designed and introduced into naphthalene-diimide-based n-channel copolymers. The synthesized polymers exhibit unipolar n-type operation with an electron mobility of up to 1.64 cm(2) V(-1) s(-1), which demonstrates the usefulness of the hybrid side chains in polymer electronics applications.

  2. Hybrid microscopy of human carotid atheroma by means of optical-resolution optoacoustic and non-linear optical microscopy

    Science.gov (United States)

    Seeger, Markus; Karlas, Angelos; Soliman, Dominik; Pelisek, Jaroslav; Ntziachristos, Vasilis

    2017-03-01

    Carotid atheromatosis is causally related to stroke, a leading cause of disability and death. We present the analysis of a human carotid atheroma using a novel hybrid microscopy system that combines optical-resolution optoacoustic (photoacoustic) microscopy and several non-linear optical microscopy modalities (second and third harmonic generation, as well as, two-photon excitation fluorescence) to achieve a multimodal examination of the extracted tissue within the same imaging framework. Our system enables the label-free investigation of atheromatous human carotid tissue with a resolution of about 1 μm and allows for the congruent interrogation of plaque morphology and clinically relevant constituents such as red blood cells, collagen, and elastin. Our data reveal mutual interactions between blood embeddings and connective tissue within the atheroma, offering comprehensive insights into its stage of evolution and severity, and potentially facilitating the further development of diagnostic tools, as well as treatment strategies.

  3. Evaluation Of Electrical And Thermal Performance Of A Linear Hybrid CPV-T Micro-Concentrator System

    Science.gov (United States)

    Everett, Vernie; Harvey, Judy; Surve, Sachin; Thomsen, Elizabeth; Walter, Daniel; Vivar, Marta; Blakers, Andrew; Tanner, Andrew; Greaves, Mikal; Le Leivre, Peter

    2011-12-01

    Chromasun Inc. and The Australian National University have developed a low-concentration, linear, hybrid micro-concentrator (MCT) system suitable for urban rooftop installation. The system produces both electrical and thermal power, integrating the functionality of separate flat plate photovoltaic and solar hot water systems. The MCT system utilises industry-standard components, including modified mono-crystalline silicon one-sun solar cells, commonly used in flat panel applications. The MCT manufacturing processes are designed around low-cost methods, and tap directly into existing economies of scale. Initial test results without any system optimisation has demonstrated an electrical output of more than 300 W, and a thermal output of more than 1500 W at 950 W/m2 DNI.

  4. Accurate localized resolution of identity approach for linear-scaling hybrid density functionals and for many-body perturbation theory

    Science.gov (United States)

    Ihrig, Arvid Conrad; Wieferink, Jürgen; Zhang, Igor Ying; Ropo, Matti; Ren, Xinguo; Rinke, Patrick; Scheffler, Matthias; Blum, Volker

    2015-09-01

    A key component in calculations of exchange and correlation energies is the Coulomb operator, which requires the evaluation of two-electron integrals. For localized basis sets, these four-center integrals are most efficiently evaluated with the resolution of identity (RI) technique, which expands basis-function products in an auxiliary basis. In this work we show the practical applicability of a localized RI-variant (‘RI-LVL’), which expands products of basis functions only in the subset of those auxiliary basis functions which are located at the same atoms as the basis functions. We demonstrate the accuracy of RI-LVL for Hartree-Fock calculations, for the PBE0 hybrid density functional, as well as for RPA and MP2 perturbation theory. Molecular test sets used include the S22 set of weakly interacting molecules, the G3 test set, as well as the G2-1 and BH76 test sets, and heavy elements including titanium dioxide, copper and gold clusters. Our RI-LVL implementation paves the way for linear-scaling RI-based hybrid functional calculations for large systems and for all-electron many-body perturbation theory with significantly reduced computational and memory cost.

  5. Linear benchmarks between the hybrid codes HYMAGYC and HMGC to study energetic particle driven Alfvénic modes

    Science.gov (United States)

    Fogaccia, G.; Vlad, G.; Briguglio, S.

    2016-11-01

    Resonant interaction between energetic particles (EPs), produced by fusion reactions and/or additional heating systems, and shear Alfvén modes can destabilize global Alfvénic modes enhancing the EP transport. In order to investigate the EP transport in present and next generation fusion devices, numerical simulations are recognized as a very important tool. Among the various numerical models, the hybrid MHD gyrokinetic one has shown to be a valid compromise between a sufficiently accurate wave-particle interaction description and affordable computational resource requirements. This paper presents a linear benchmark between the hybrid codes HYMAGYC and HMGC. The HYMAGYC code solves the full, linear MHD equations in general curvilinear geometry for the bulk plasma and describes the EP population by the nonlinear gyrokinetic Vlasov equation. On the other side, HMGC solves the nonlinear, reduced O≤ft(ε 03\\right) , pressureless MHD equations ({ε0} being the inverse aspect ratio) for the bulk plasma and the drift kinetic Vlasov equation for the EPs. The results of the HYMAGYC and HMGC codes have been compared both in the MHD limit and in a wide range of the EP parameter space for two test cases (one of which being the so-called TAE n  =  6 ITPA Energetic Particle Group test case), both characterized by {ε0}\\ll 1 . In the first test case (test case A), good qualitative agreement is found w.r.t. real frequencies, growth rates and spatial structures of the most unstable modes, with some quantitative differences for the growth rates. For the so-called ITPA test case (test case B), at the nominal energetic particle density value, the disagreement between the two codes is, on the contrary, also qualitative, as a different mode is found as the most unstable one.

  6. Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide) and Poly(Butadiene-b-Ethylene Oxide) Block Copolymers.

    Science.gov (United States)

    Gaspard, Jeffery; Casey, Liam M; Rozin, Matt; Munoz-Pinto, Dany J; Silas, James A; Hahn, Mariah S

    2016-03-18

    Poly(dimethylsiloxane-ethylene oxide) (PDMS-PEO) and poly(butadiene-b-ethylene oxide) (PBd-PEO) are two block copolymers which separately form vesicles with disparate membrane permeabilities and fluidities. Thus, hybrid vesicles formed from both PDMS-PEO and PBd-PEO may ultimately allow for systematic, application-specific tuning of vesicle membrane fluidity and permeability. However, given the relatively low strength previously noted for comb-type PDMS-PEO vesicles, the mechanical robustness of the resulting hybrid vesicles must first be confirmed. Toward this end, we have characterized the mechanical behavior of vesicles formed from mixtures of linear PDMS-PEO and linear PBd-PEO using micropipette aspiration. Tension versus strain plots of pure PDMS12-PEO46 vesicles revealed a non-linear response in the high tension regime, in contrast to the approximately linear response of pure PBd33-PEO20 vesicles. Remarkably, the area expansion modulus, critical tension, and cohesive energy density of PDMS12-PEO46 vesicles were each significantly greater than for PBd33-PEO20 vesicles, although critical strain was not significantly different between these vesicle types. PDMS12-PEO46/PBd33-PEO20 hybrid vesicles generally displayed graded responses in between that of the pure component vesicles. Thus, the PDMS12-PEO46/PBd33-PEO20 hybrid vesicles retained or exceeded the strength and toughness characteristic of pure PBd-PEO vesicles, indicating that future assessment of the membrane permeability and fluidity of these hybrid vesicles may be warranted.

  7. Broadband Energy Harvester Using Non-linear Polymer Spring and Electromagnetic/Triboelectric Hybrid Mechanism

    Science.gov (United States)

    Gupta, Rahul Kumar; Shi, Qiongfeng; Dhakar, Lokesh; Wang, Tao; Heng, Chun Huat; Lee, Chengkuo

    2017-01-01

    Over the years, several approaches have been devised to widen the operating bandwidth, but most of them can only be triggered at high accelerations. In this work, we investigate a broadband energy harvester based on combination of non-linear stiffening effect and multimodal energy harvesting to obtain high bandwidth over wide range of accelerations (0.1 g–2.0 g). In order to achieve broadband behavior, a polymer based spring exhibiting multimodal energy harvesting is used. Besides, non-linear stiffening effect is introduced by using mechanical stoppers. At low accelerations (energy-harvesting, the obtained bandwidth increases from 23 Hz to 68 Hz with percentage increment of 295% at 1.8 g. Further, we have demonstrated the triboelectric output measured as acceleration sensing signals in terms of voltage and current sensitivity of 4.7 Vg−1 and 19.7 nAg−1, respectively. PMID:28120924

  8. Ultra high performance liquid chromatography-time-of-flight high resolution mass spectrometry in the analysis of hexabromocyclododecane diastereomers: method development and comparative evaluation versus ultra high performance liquid chromatography coupled to Orbitrap high resolution mass spectrometry and triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Zacs, D; Rjabova, J; Pugajeva, I; Nakurte, I; Viksna, A; Bartkevics, V

    2014-10-31

    An efficient ultra high performance liquid chromatography (UHPLC)-time-of-flight high resolution mass spectrometry (TOF-HRMS) method was elaborated for the determination of hexabromocyclododecane (HBCD) diastereomers in fish samples and compared against UHPLC-Orbitrap-HRMS and UHPLC-triple quadrupole (QqQ) tandem MS (MS/MS) techniques. The TOF-HRMS analyzer was operated at high resolution (>10000 full width at half maximum (FWHM)) with scanning the m/z range from 600 to 700, to achieve picogram quantitation limits. The effects of various operational parameters on the instrumental response were systematically investigated. Evaluation of the influence of sample clean-up procedure steps on signal suppression effect including removal of the matrix components by means of destructive acidic treatment or non-destructive gel permeation chromatography (GPC), and additional Florisil column chromatography step showed that the analytical response of UHPLC-TOF-HRMS system is much more affected by the presence of matrix components in the final extracts in comparison with UHPLC-Orbitrap-HRMS and UHPLC-QqQ-MS/MS systems. The method was robustly validated and used for the analysis of eel (Anquilla anquilla) samples originating from a Latvian lake. UHPLC-TOF-HRMS showed a suitable performance under the optimized conditions: recoveries for three selected diastereomers in the range of 99-116%; repeatability and intermediate precision expressed as relative standard deviation (RSD) in the ranges of 2.3-7.1% and 2.9-8.1%, respectively. The elaborated method achieved instrumental limits of quantification (i-LOQ) of 0.9-4.5pg on column that were suitable for the trace analysis of three HBCD diastereomers, corresponding to the method limits of quantification (m-LOQ) of 7.0-29pgg(-1) wet weight (w.w.). The efficiency of UHPLC-TOF-HRMS method was evaluated by comparing the performance characteristics and analytical data from real samples with the validation data and real sample results

  9. 高效液相色谱-质谱联用技术对缬草三酯稳定性的研究%Investigation of the long-term stability and forced degradation of valtrate by high performance liquid chromatography coupled with triple quadrupole tandem mass spectrometry

    Institute of Scientific and Technical Information of China (English)

    王菲菲; 王明娟; 张聿梅; 王琰; 于健东; 王瑞忠; 程显龙; 汪祺; 郑笑为

    2014-01-01

    Valtrate is the main drug quality control for the qualitative and quantitative analysis of Valerian medicines in the Chinese Pharmacopoeia 2010.However,valtrate is unstable under some conditions.We,for the first time,systemically evaluated the stability of two bath reference standards (RS) by high performance liquid chromatography coupled with a triple quadrupole mass spectrometer (HPLC-MS/MS).The forced degradations of valtrate were performed to evaluate its optimal storage,transportation and experiment conditions according to ICH guideline.The developed HPLC method was validated to determine the degradation products.Valtrate RS was sensitive to alkaline and thermal conditions,but it was relatively stable under acidic,oxidation and photolysis conditions.A total of nine degradation components were identified under alkaline hydrolysis (N l-N4) and thermal degradation (B1-B5).The information obtained in this work would be valuable to minimize the decomposition of valtrate during the processes of preparation,storage,distribution and utilization.It was highly suggested to store valtrate with a single dose packing in brown closed ampoule at-20 ℃C.Under the above-mentioned storage condition,valtrate could be stable for up to 3 years.%缬草三酯属于多酰基类环烯醚萜化合物.中国药典2010年版一部蜘蛛香项下收载缬草三酯作为质量控制对照品使用.然而,结构不稳定是该类对照品发放中亟待解决的问题.本文通过高效液相色谱-质谱联用的方法对缬草三酯的稳定性进行了研究.根据ICH导则要求,使用加速稳定性实验对缬草三酯适宜贮存条件、运输和实验条件进行研究.结果表明,缬草三酯在碱性和加热条件下不稳定,而在酸性、氧化和强光照射条件下保持相对稳定.实验中有九个缬草三酯降解产物被检出,其中N1-N4为碱性水解时产生,B1-B5为热降解中产生.研究结果为本对照品的稳定性分析提供了

  10. Hybrid Model Representation of a TLP Including Flexible Topsides in Non-Linear Regular Waves

    Directory of Open Access Journals (Sweden)

    Christof Wehmeyer

    2014-08-01

    Full Text Available The rising demand for renewable energy solutions is forcing the established industries to expand and continue evolving. For the wind energy sector, the vast resources in deep sea locations have encouraged research towards the installation of turbines in deeper waters. One of the most promising technologies able to solve this challenge is the floating wind turbine foundation. For the ultimate limit state, where higher order wave loads have a significant influence, a design tool that couples non-linear excitations with structural dynamics is required. To properly describe the behavior of such a structure, a numerical model is proposed and validated by physical test results. The model is applied to a case study of a tension leg platform with a flexible topside mimicking the tower and a lumped mass mimicking the rotor-nacelle assembly. The model is additionally compared to current commercial software, where the need for the coupled higher order dynamics proposed in this paper becomes evident.

  11. Internal transport barrier triggered by non-linear lower hybrid wave deposition under condition of beam-driven toroidal rotation

    Energy Technology Data Exchange (ETDEWEB)

    Gao, Q. D., E-mail: qgao@swip.ac.cn [Southwestern Institute of Physics, Chengdu 610041 (China); Budny, R. V. [Princeton Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2015-03-15

    By using gyro-Landau fluid transport model (GLF23), time-dependent integrated modeling is carried out using TRANSP to explore the dynamic process of internal transport barrier (ITB) formation in the neutral beam heating discharges. When the current profile is controlled by LHCD (lower hybrid current drive), with appropriate neutral beam injection, the nonlinear interplay between the transport determined gradients in the plasma temperature (T{sub i,e}) and toroidal velocity (V{sub ϕ}) and the E×B flow shear (including q-profile) produces transport bifurcations, generating spontaneously a stepwise growing ITB. In the discharge, the constraints imposed by the wave propagation condition causes interplay of the LH driven current distribution with the plasma configuration modification, which constitutes non-linearity in the LH wave deposition. The non-linear effects cause bifurcation in LHCD, generating two distinct quasi-stationary reversed magnetic shear configurations. The change of current profile during the transition period between the two quasi-stationary states results in increase of the E×B shearing flow arising from toroidal rotation. The turbulence transport suppression by sheared E×B flow during the ITB development is analysed, and the temporal evolution of some parameters characterized the plasma confinement is examined. Ample evidence shows that onset of the ITB development is correlated with the enhancement of E×B shearing rate caused by the bifurcation in LHCD. It is suggested that the ITB triggering is associated with the non-linear effects of the LH power deposition.

  12. Hybrid concept for the parameterization of the cascade of linear reservoirs for river flow routing using artificial neural networks

    Science.gov (United States)

    Úrek, Peter Å.; Szolgay, Jan; Čistý, Milan

    2010-05-01

    The lack of hydraulic and morphological data in many cases does not allow for using hydraulic methods for the simulation of the flood wave transformation between two river cross-sections. Under such conditions, as a rational alternative to hydraulic routing, hydrological routing models appear to be a suitable in the practice for flow forecasting. These models, beside numerical hydraulic models (and also models belonging to the class of non-storage routing methods), are in operational use in Slovakia. Usually, the morphological and hydraulic characteristics of the modelled river reaches and of the flow conditions are reflected in the routing model parameters, which are estimated by calibration and are kept constant for a given model during the simulation. In this contribution a new hybrid concept of model parameterization of the KLN model is presented. The KLN model is based on the state-space representation of the cascade of linear reservoirs. In the multilinear concept the travel-time parameter of the model was allowed to vary during simulation according to changing flow conditions. The model parameter changes in time according to an assumed relationship between the travel time of flood peaks and of selected characteristics of the flood wave. This relationship was estimated using artificial neural networks (ANN). In order to include all several possible effects, several setups of the ANN, which could possibly affect the model parameter, were tested. The ANN was trained to estimate the optimal values of model parameter and is used on- line during the routing procedure. The proposed hybrid concept is compared with other models used in practice.

  13. Incorporated W Roles on Microstructure and Properties of W-C:H Films by a Hybrid Linear Ion Beam Systems

    Directory of Open Access Journals (Sweden)

    Peng Guo

    2013-01-01

    Full Text Available W-incorporated diamond-like carbon (W-C:H films were fabricated by a hybrid beams system consisting of a DC magnetron sputtering and a linear ion source. The W concentration (1.08~31.74 at.% in the film was controlled by varying the sputtering current. The cross-sectional topography, composition, and microstructure of the W-C:H films were investigated by SEM, XPS, TEM, and Raman spectroscopy. The mechanical and tribological properties of the films as a function of W concentration were evaluated by a stress-tester, nanoindentation, and ball-on-disk tribometer, respectively. The results showed that films mainly exhibited the feature of amorphous carbon when W concentration of the films was less than 4.38 at.%, where the incorporated W atoms would be bonded with C atoms and resulted in the formation of WC1-x nanoparticles. The W-C:H film with 4.38 at.% W concentration showed a minimum value of residual compressive stress, a higher hardness, and better tribological properties. Beyond this W concentration range, both the residual stress and mechanical properties were deteriorated due to the growth of tungsten carbide nanoparticles in the carbon matrix.

  14. Crude oil price forecasting based on hybridizing wavelet multiple linear regression model, particle swarm optimization techniques, and principal component analysis.

    Science.gov (United States)

    Shabri, Ani; Samsudin, Ruhaidah

    2014-01-01

    Crude oil prices do play significant role in the global economy and are a key input into option pricing formulas, portfolio allocation, and risk measurement. In this paper, a hybrid model integrating wavelet and multiple linear regressions (MLR) is proposed for crude oil price forecasting. In this model, Mallat wavelet transform is first selected to decompose an original time series into several subseries with different scale. Then, the principal component analysis (PCA) is used in processing subseries data in MLR for crude oil price forecasting. The particle swarm optimization (PSO) is used to adopt the optimal parameters of the MLR model. To assess the effectiveness of this model, daily crude oil market, West Texas Intermediate (WTI), has been used as the case study. Time series prediction capability performance of the WMLR model is compared with the MLR, ARIMA, and GARCH models using various statistics measures. The experimental results show that the proposed model outperforms the individual models in forecasting of the crude oil prices series.

  15. Crude Oil Price Forecasting Based on Hybridizing Wavelet Multiple Linear Regression Model, Particle Swarm Optimization Techniques, and Principal Component Analysis

    Directory of Open Access Journals (Sweden)

    Ani Shabri

    2014-01-01

    Full Text Available Crude oil prices do play significant role in the global economy and are a key input into option pricing formulas, portfolio allocation, and risk measurement. In this paper, a hybrid model integrating wavelet and multiple linear regressions (MLR is proposed for crude oil price forecasting. In this model, Mallat wavelet transform is first selected to decompose an original time series into several subseries with different scale. Then, the principal component analysis (PCA is used in processing subseries data in MLR for crude oil price forecasting. The particle swarm optimization (PSO is used to adopt the optimal parameters of the MLR model. To assess the effectiveness of this model, daily crude oil market, West Texas Intermediate (WTI, has been used as the case study. Time series prediction capability performance of the WMLR model is compared with the MLR, ARIMA, and GARCH models using various statistics measures. The experimental results show that the proposed model outperforms the individual models in forecasting of the crude oil prices series.

  16. Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide and Poly(Butadiene-b-Ethylene Oxide Block Copolymers

    Directory of Open Access Journals (Sweden)

    Jeffery Gaspard

    2016-03-01

    Full Text Available Poly(dimethylsiloxane-ethylene oxide (PDMS-PEO and poly(butadiene-b-ethylene oxide (PBd-PEO are two block copolymers which separately form vesicles with disparate membrane permeabilities and fluidities. Thus, hybrid vesicles formed from both PDMS-PEO and PBd-PEO may ultimately allow for systematic, application-specific tuning of vesicle membrane fluidity and permeability. However, given the relatively low strength previously noted for comb-type PDMS-PEO vesicles, the mechanical robustness of the resulting hybrid vesicles must first be confirmed. Toward this end, we have characterized the mechanical behavior of vesicles formed from mixtures of linear PDMS-PEO and linear PBd-PEO using micropipette aspiration. Tension versus strain plots of pure PDMS12-PEO46 vesicles revealed a non-linear response in the high tension regime, in contrast to the approximately linear response of pure PBd33-PEO20 vesicles. Remarkably, the area expansion modulus, critical tension, and cohesive energy density of PDMS12-PEO46 vesicles were each significantly greater than for PBd33-PEO20 vesicles, although critical strain was not significantly different between these vesicle types. PDMS12-PEO46/PBd33-PEO20 hybrid vesicles generally displayed graded responses in between that of the pure component vesicles. Thus, the PDMS12-PEO46/PBd33-PEO20 hybrid vesicles retained or exceeded the strength and toughness characteristic of pure PBd-PEO vesicles, indicating that future assessment of the membrane permeability and fluidity of these hybrid vesicles may be warranted.

  17. Hybrid fusion of linear, non-linear and spectral models for the dynamic modeling of sEMG and skeletal muscle force: an application to upper extremity amputation.

    Science.gov (United States)

    Potluri, Chandrasekhar; Anugolu, Madhavi; Schoen, Marco P; Subbaram Naidu, D; Urfer, Alex; Chiu, Steve

    2013-11-01

    Estimating skeletal muscle (finger) forces using surface Electromyography (sEMG) signals poses many challenges. In general, the sEMG measurements are based on single sensor data. In this paper, two novel hybrid fusion techniques for estimating the skeletal muscle force from the sEMG array sensors are proposed. The sEMG signals are pre-processed using five different filters: Butterworth, Chebychev Type II, Exponential, Half-Gaussian and Wavelet transforms. Dynamic models are extracted from the acquired data using Nonlinear Wiener Hammerstein (NLWH) models and Spectral Analysis Frequency Dependent Resolution (SPAFDR) models based system identification techniques. A detailed comparison is provided for the proposed filters and models using 18 healthy subjects. Wavelet transforms give higher mean correlation of 72.6 ± 1.7 (mean ± SD) and 70.4 ± 1.5 (mean ± SD) for NLWH and SPAFDR models, respectively, when compared to the other filters used in this work. Experimental verification of the fusion based hybrid models with wavelet transform shows a 96% mean correlation and 3.9% mean relative error with a standard deviation of ± 1.3 and ± 0.9 respectively between the overall hybrid fusion algorithm estimated and the actual force for 18 test subjects' k-fold cross validation data.

  18. Simulation and performance evaluation of shunt hybrid power filter using fuzzy logic based non-linear control for power quality improvement

    Indian Academy of Sciences (India)

    R BALASUBRAMANIAN; R SANKARAN; S PALANI

    2017-09-01

    This paper deals with design and simulation of a three-phase shunt hybrid power filter consisting of a pair of 5th and 7th selective harmonic elimination passive power filters connected in series with a conventional active power filter with reduced kVA rating. The objective is to enhance the power quality in a distributionnetwork feeding variety of non-linear, time-varying and unbalanced loads. The theory and modelling of the entire power circuit in terms of synchronously rotating reference frame and leading to a non-linear control scheme is presented. This work involves introduction of individual fuzzy logic controllers for d and q axiscurrent control and for voltage regulation of the DC link capacitor. The simulation schematic covering the power and control circuits have been developed taking into account severe harmonic distortion caused by non-linear and unbalanced loads. The effectiveness of the fuzzy logic controller for the compensation of harmonics and reactive power has been verified by successive simulation runs and analysis of the results. The proposed controller is also able to compensate the distortion generated by the voltage- and current-fed non-linear loads, unbalanced and dynamically varying loads. Further, excellent regulation of the DC link voltage is accomplished, which significantly contributes to improvement of power quality.

  19. A New Therapeutic Paradigm for Breast Cancer Exploiting Low Dose Estrogen-Induced Apoptosis

    Science.gov (United States)

    2011-06-01

    with MALDI-TOF/TOF 4800 (AB Sciex , Framingham, MA) or using reversed phase nanoUPLC Acquity (Waters) coupled to ESI-Q-STAR quadrupole/ orthogonal...TOF (AB Sciex , Framingham, MA) or on E SI-4000 QTRAP hybrid triple quadrupole/linear ion trap mass spectrometer (AB Sciex , Framingham, MA). For LC...ionsource (AB Sciex , Framingham, MA). Eluted peptides were ionized in positive mode using a fused silica PicoTip emitter (outer diameter 75 μm inner

  20. Application of the linear/exponential hybrid force field scaling scheme to the bond length alternation modes of polyacetylene

    Science.gov (United States)

    Yang, Shujiang; Kertesz, Miklos

    2006-12-01

    The two bond length alternation related backbone carbon-carbon stretching Raman active normal modes of polyacetylene are notoriously difficulty to predict theoretically. We apply our new linear/exponential scaled quantum mechanical force field scheme to tackle this problem by exponentially adjusting the decay of the coupling force constants between backbone stretchings based on their distance which extends over many neighbors. With transferable scaling parameters optimized by least squares fitting to the experimental vibrational frequencies of short oligoenes, the scaled frequencies of trans-polyacetylene and its isotopic analogs agree very well with experiments. The linear/exponential scaling scheme is also applicable to the cis-polyacetylene case.

  1. Estimating biomass of mixed and uneven-aged forests using spectral data and a hybrid model combining regression trees and linear models

    Directory of Open Access Journals (Sweden)

    López-Serrano PM

    2016-04-01

    Full Text Available The Sierra Madre Occidental mountain range (Durango, Mexico is of great ecological interest because of the high degree of environmental heterogeneity in the area. The objective of the present study was to estimate the biomass of mixed and uneven-aged forests in the Sierra Madre Occidental by using Landsat-5 TM spectral data and forest inventory data. We used the ATCOR3® atmospheric and topographic correction module to convert remotely sensed imagery digital signals to surface reflectance values. The usual approach of modeling stand variables by using multiple linear regression was compared with a hybrid model developed in two steps: in the first step a regression tree was used to obtain an initial classification of homogeneous biomass groups, and multiple linear regression models were then fitted to each node of the pruned regression tree. Cross-validation of the hybrid model explained 72.96% of the observed stand biomass variation, with a reduction in the RMSE of 25.47% with respect to the estimates yielded by the linear model fitted to the complete database. The most important variables for the binary classification process in the regression tree were the albedo, the corrected readings of the short-wave infrared band of the satellite (2.08-2.35 µm and the topographic moisture index. We used the model output to construct a map for estimating biomass in the study area, which yielded values of between 51 and 235 Mg ha-1. The use of regression trees in combination with stepwise regression of corrected satellite imagery proved a reliable method for estimating forest biomass.

  2. Comparison of analytical and clinical performance of CLART HPV2 genotyping assay to Linear Array and Hybrid Capture 2

    DEFF Research Database (Denmark)

    Ejegod, Ditte Møller; Rebolj, Matejka; Bonde, Jesper

    2015-01-01

    prone to inter-observer variability. The reading of test results on the CLART HPV2 genotyping assay is, on the other hand, automated. The aim of our study was to directly compare the detection of HPV genotypes and high-grade cervical intraepithelial neoplasia (CIN) by CLART, Linear Array (LA...

  3. Quantum, classical, and hybrid QM/MM calculations in solution: General implementation of the ddCOSMO linear scaling strategy

    Energy Technology Data Exchange (ETDEWEB)

    Lipparini, Filippo, E-mail: flippari@uni-mainz.de [Sorbonne Universités, UPMC Univ. Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005 Paris (France); Sorbonne Universités, UPMC Univ. Paris 06, UMR 7616, Laboratoire de Chimie Théorique, F-75005 Paris (France); Sorbonne Universités, UPMC Univ. Paris 06, Institut du Calcul et de la Simulation, F-75005 Paris (France); Scalmani, Giovanni; Frisch, Michael J. [Gaussian, Inc., 340 Quinnipiac St. Bldg. 40, Wallingford, Connecticut 06492 (United States); Lagardère, Louis [Sorbonne Universités, UPMC Univ. Paris 06, Institut du Calcul et de la Simulation, F-75005 Paris (France); Stamm, Benjamin [Sorbonne Universités, UPMC Univ. Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005 Paris (France); CNRS, UMR 7598 and 7616, F-75005 Paris (France); Cancès, Eric [Université Paris-Est, CERMICS, Ecole des Ponts and INRIA, 6 and 8 avenue Blaise Pascal, 77455 Marne-la-Vallée Cedex 2 (France); Maday, Yvon [Sorbonne Universités, UPMC Univ. Paris 06, UMR 7598, Laboratoire Jacques-Louis Lions, F-75005 Paris (France); Institut Universitaire de France, Paris, France and Division of Applied Maths, Brown University, Providence, Rhode Island 02912 (United States); Piquemal, Jean-Philip [Sorbonne Universités, UPMC Univ. Paris 06, UMR 7616, Laboratoire de Chimie Théorique, F-75005 Paris (France); CNRS, UMR 7598 and 7616, F-75005 Paris (France); Mennucci, Benedetta [Dipartimento di Chimica e Chimica Industriale, Università di Pisa, Via Risorgimento 35, 56126 Pisa (Italy)

    2014-11-14

    We present the general theory and implementation of the Conductor-like Screening Model according to the recently developed ddCOSMO paradigm. The various quantities needed to apply ddCOSMO at different levels of theory, including quantum mechanical descriptions, are discussed in detail, with a particular focus on how to compute the integrals needed to evaluate the ddCOSMO solvation energy and its derivatives. The overall computational cost of a ddCOSMO computation is then analyzed and decomposed in the various steps: the different relative weights of such contributions are then discussed for both ddCOSMO and the fastest available alternative discretization to the COSMO equations. Finally, the scaling of the cost of the various steps with respect to the size of the solute is analyzed and discussed, showing how ddCOSMO opens significantly new possibilities when cheap or hybrid molecular mechanics/quantum mechanics methods are used to describe the solute.

  4. HybridSPE: A novel technique to reduce phospholipid-based matrix effect in LC-ESI-MS Bioanalysis.

    Science.gov (United States)

    Ahmad, Shafeeque; Kalra, Harsh; Gupta, Amit; Raut, Bharat; Hussain, Arshad; Rahman, Md Akhlaquer

    2012-10-01

    When complex biological materials are analyzed without an adequate sample preparation technique, MS signal and response undergo significant alteration and result in poor quantification and assay. This problem generally takes place due to the presence of several endogenous materials component in samples. One of the major causes of ion suppression in bioanalysis is the presence of phospholipids during LC-MS analysis. The phospholipid-based matrix effect was investigated with a commercially available electro spray ionization (ESI) source coupled with a triple quadrupole mass spectrometer. HybridSPE dramatically reduced the levels of residual phospholipids in biological samples, leading to significant reduction in matrix effects. This new procedure that combines the simplicity of precipitation with the selectivity of SPE allows obtaining much cleaner extracts than with conventional procedures. HybridSPE-precipitation procedure provides significant improvement in bioanalysis and a practical and fast way to ensure the avoidance of phospholipids-based matrix effects. The present review outlines the HybridSPE technique to minimize phospholipids-based matrix effects on LC-ESI-MS bioanalysis.

  5. HybridSPE: A novel technique to reduce phospholipid-based matrix effect in LC-ESI-MS Bioanalysis

    Directory of Open Access Journals (Sweden)

    Shafeeque Ahmad

    2012-01-01

    Full Text Available When complex biological materials are analyzed without an adequate sample preparation technique, MS signal and response undergo significant alteration and result in poor quantification and assay. This problem generally takes place due to the presence of several endogenous materials component in samples. One of the major causes of ion suppression in bioanalysis is the presence of phospholipids during LC-MS analysis. The phospholipid-based matrix effect was investigated with a commercially available electro spray ionization (ESI source coupled with a triple quadrupole mass spectrometer. HybridSPE dramatically reduced the levels of residual phospholipids in biological samples, leading to significant reduction in matrix effects. This new procedure that combines the simplicity of precipitation with the selectivity of SPE allows obtaining much cleaner extracts than with conventional procedures. HybridSPE-precipitation procedure provides significant improvement in bioanalysis and a practical and fast way to ensure the avoidance of phospholipids-based matrix effects. The present review outlines the HybridSPE technique to minimize phospholipids-based matrix effects on LC-ESI-MS bioanalysis.

  6. Measurement of the third order non-linearity of gold-graphene hybrid nanocomposite for near-infrared wavelengths

    Science.gov (United States)

    Syed, Salmaan R.; Lim, Guh-Hwan; Lim, Byungkwon; Chon, James W. M.

    2016-04-01

    We present measurements of nonlinear refraction (NLR) and nonlinear absorption (NLA) of single crystalline gold nanosheets (single crystalline-GNSs) and sputter coated polycrystalline thin gold metal film hybridized with multilayer grapheme (MLG) using Z-Scan technique for near-infrared wavelengths (NIR) ranging from 700 nm to 900 nm. Single crystalline GNSs of 20 nm thickness were prepared through chemical synthesis. MLG was found to have few monolayers of graphene, usually between 1-7 layers with an average of 4 monolayer thickness. The composite of GNSs and MLG was prepared by drop casting GNSs on MLG. Z-Scan experimental was carried out using Ti:sapphire femtosecond pulsed laser (700 nm - 900 nm wavelength, 115-130 fs pulse width and 0.82 MHz-82 MHz repetition rate). Intensity dependence on open aperture Z-scan was studied in detail for all materials. The NLA of polycrystalline thin gold metal film was found to be fractionally higher than that of single crystalline-GNSs. This is thought to be due to field enhancement around of gold islands formed on polycrystalline thin gold metal film during sputtering process. At higher repetition rates NLA phenomenon is diminished due to the temperature accumulation effect. As the repetition rate decreases the nonlinear effect is enhanced. On the other hand MLG exhibited saturable absorption (NSA) . Z-Scan results for single crystalline and poly crystalline gold-MLG nanocomposite exhibit NSA characteristics. The measured NSA coefficient `α' was found to be approximately ≍1.7×10-5-4.5×10-5 cmW-1 which is lower than that of MLG, clearly demonstrating the effect of hybridization.

  7. Synthesis and non linear optical properties of new inorganic-organic hybrid material: 4-Benzylpiperidinium sulfate monohydrate

    Science.gov (United States)

    Kessentini, Yassmin; Ahmed, Ali Ben; Al-Juaid, Salih S.; Mhiri, Tahar; Elaoud, Zakaria

    2016-03-01

    Single crystals of 4-benzyl-piperidine sulfate monohydrate were grown by slow evaporation method at room temperature. The synthesized compound was characterized by means of single-crystal X-ray diffraction, FT-IR and Raman spectroscopy, UV-visible and photoluminescence studies. The title compound crystallises at room temperature in the non centrosymmetric space group P212121.The recorded UV-visible spectrum show good transparency in the visible region and indicates a non-zero value of the first Hyperpolarizability. Photoluminescence spectrum shows a broad and intense band at 440 nm and indicates that the crystal emits blue fluorescence. We also report DFT calculations of the electric dipole moments (μ), Polarizability (α), the static first Hyperpolarizability (β) and HOMO-LUMO analysis of the title compound was theoretically investigated by GAUSSIAN 03 package. The calculated static first Hyperpolarizability is equal to 6.4022 × 10-31 esu. The results show that 4-benzyl-piperidine sulfate monohydrate crystal might have important non linear optical behavior and can be a potential non linear optical material of interest.

  8. Penalized linear regression for discrete ill-posed problems: A hybrid least-squares and mean-squared error approach

    KAUST Repository

    Suliman, Mohamed

    2016-12-19

    This paper proposes a new approach to find the regularization parameter for linear least-squares discrete ill-posed problems. In the proposed approach, an artificial perturbation matrix with a bounded norm is forced into the discrete ill-posed model matrix. This perturbation is introduced to enhance the singular-value (SV) structure of the matrix and hence to provide a better solution. The proposed approach is derived to select the regularization parameter in a way that minimizes the mean-squared error (MSE) of the estimator. Numerical results demonstrate that the proposed approach outperforms a set of benchmark methods in most cases when applied to different scenarios of discrete ill-posed problems. Jointly, the proposed approach enjoys the lowest run-time and offers the highest level of robustness amongst all the tested methods.

  9. Hybrid solar cells based on blends of poly(3-hexylthiophene) and surface dye-modified, ultrathin linear- and branched-TiO{sub 2} nanorods

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Jie [Department of Chemistry, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Experimental Teaching Center, Guangdong University of Technology, Guangzhou 510006 (China); Liu, Chenmin; Yang, Shihe [Department of Chemistry, William Mong Institute of Nano Science and Technology, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong (China); Cao, Yong [Institute of Polymer Optoelectronic Materials and Devices, Key Laboratory of Special Functional Materials and Advanced Manufacturing Technology, South China University of Technology, Guangzhou 510640 (China)

    2010-03-15

    We report on a comparative study of hybrid solar cells based on blends of poly(3-hexylthiophene) (P3HT) and TiO{sub 2} nanorods. Two types of ultrathin TiO{sub 2} nanorods, linear and branched, have been synthesized for the first time, and surface modified with different dyes before blending with P3HT. Using pristine P3HT as a reference, the short-circuit current and energy conversion efficiency of poly(3-hexylthiophene)/pyridine-HgBrRed-modified branched-TiO{sub 2} solar cells were increased by over an order of magnitude, which were also 2-3 times those of the corresponding linear-TiO{sub 2} cells. Our results indicate that the branching and the surface dye modification of TiO{sub 2} nanorods could effectively facilitate charge transport in the nanostructured network and exciton dissociation at the inorganic/organic interfaces. Thermal treatment of the blend films was found to further increase the efficiency up to 0.16%. (author)

  10. Analysis of test-beam data with hybrid pixel detector prototypes for the Compact LInear Collider (CLIC) vertex detectors

    CERN Document Server

    Pequegnot, Anne-Laure

    2013-01-01

    The LHC is currently the most powerful accelerator in the world. This proton-proton collider is now stoppped to increase significantly its luminosity and energy, which would provide a larger discovery potential in 2014 and beyond. A high-energy $e^{+}e^{-}$ collider, such as CLIC, is an option to complement and to extend the LHC physics programme. Indeed, a lepton collider gives access to additional physics processes, beyond those observable at the LHC, and therefore provides new discovery potential. It can also provide complementary and/or more precise information about new physics uncovered at the LHC. Many essential features of a detector are required to deliver the full physics potential of this CLIC machine. In this present report, I present my work on the vertex detector R\\&D for this future linear collider, which aims at developping highly granular and ultra-thin position sensitive detection devices with very low power consumption and fast time-stamping capability. We tested here thin silicon pixel...

  11. Comprehensive lipidome analysis by shotgun lipidomics on a hybrid quadrupole-orbitrap-linear ion trap mass spectrometer.

    Science.gov (United States)

    Almeida, Reinaldo; Pauling, Josch Konstantin; Sokol, Elena; Hannibal-Bach, Hans Kristian; Ejsing, Christer S

    2015-01-01

    Here we report on the application of a novel shotgun lipidomics platform featuring an Orbitrap Fusion mass spectrometer equipped with an automated nanoelectrospray ion source. To assess the performance of the platform for in-depth lipidome analysis, we evaluated various instrument parameters, including its high resolution power unsurpassed by any other contemporary Orbitrap instrumentation, its dynamic quantification range and its efficacy for in-depth structural characterization of molecular lipid species by quadrupole-based higher-energy collisional dissociation (HCD), and ion trap-based resonant-excitation collision-induced dissociation (CID). This evaluation demonstrated that FTMS analysis with a resolution setting of 450,000 allows distinguishing isotopes from different lipid species and features a linear dynamic quantification range of at least four orders of magnitude. Evaluation of fragmentation analysis demonstrated that combined use of HCD and CID yields complementary fragment ions of molecular lipid species. To support global lipidome analysis, we designed a method, termed MS(ALL), featuring high resolution FTMS analysis for lipid quantification, and FTMS(2) analysis using both HCD and CID and ITMS(3) analysis utilizing dual CID for in-depth structural characterization of molecular glycerophospholipid species. The performance of the MS(ALL) method was benchmarked in a comparative analysis of mouse cerebellum and hippocampus. This analysis demonstrated extensive lipidome quantification covering 311 lipid species encompassing 20 lipid classes, and identification of 202 distinct molecular glycerophospholipid species when applying a novel high confidence filtering strategy. The work presented here validates the performance of the Orbitrap Fusion mass spectrometer for in-depth lipidome analysis.

  12. A validated hybrid quadrupole linear ion-trap LC-MS method for the analysis of morphine and morphine glucuronides applied to opiate deaths.

    Science.gov (United States)

    Taylor, Kerry; Elliott, Simon

    2009-05-30

    A hybrid quadrupole linear ion-trap mass spectrometer using an electrospray ionisation ion source coupled to a HPLC system has been used to develop a method which can accurately measure morphine, morphine-3-glucuronide (M3G) and morphine-6-glucuronide (M6G) in plasma, whole blood and post-mortem blood following solid-phase extraction. The method can also qualitatively detect various other opioids and related compounds including: codeine, dihydrocodeine (and metabolites), noscapine, papaverine and 6-acetylmorphine (6-AM). The method has been favourably compared to an existing laboratory method using a now discontinued radio-immunoassay technique. The advantage of measuring the glucuronides directly rather than following deconjugation by beta-glucuronidase has also been shown. Detection and quantification of compounds was achieved using multiple reaction monitoring (MRM) incorporating the use of deuterated morphine and M3G as internal standards. Precision and accuracy was determined to be less than 10% at both high and low levels for all analytes and the calibration curve was deemed linear over an acceptable range. Recovery in blood was greater than 90% and ion suppression/enhancement was shown to be less than 15%. This method was applied to over 130 post-mortem cases involving the use of heroin, prescribed morphine and codeine. The range of concentrations of morphine, M3G and M6G was large (particularly in heroin and prescribed morphine cases), reflecting the many different factors involved with therapeutic use or fatal opiate poisonings, including tolerance associated with regular use, variable dose regimens and co-administration of other drugs. Detection of other constituents of the opium poppy such as noscapine and papaverine and metabolites of diacetylmorphine in the blood (6-AM) was useful in determining the source of the morphine (i.e. illicit heroin) and the rapidity of death after administration.

  13. Multiple and sequential data acquisition method: an improved method for fragmentation and detection of cross-linked peptides on a hybrid linear trap quadrupole Orbitrap Velos mass spectrometer.

    Science.gov (United States)

    Rudashevskaya, Elena L; Breitwieser, Florian P; Huber, Marie L; Colinge, Jacques; Müller, André C; Bennett, Keiryn L

    2013-02-05

    The identification and validation of cross-linked peptides by mass spectrometry remains a daunting challenge for protein-protein cross-linking approaches when investigating protein interactions. This includes the fragmentation of cross-linked peptides in the mass spectrometer per se and following database searching, the matching of the molecular masses of the fragment ions to the correct cross-linked peptides. The hybrid linear trap quadrupole (LTQ) Orbitrap Velos combines the speed of the tandem mass spectrometry (MS/MS) duty circle with high mass accuracy, and these features were utilized in the current study to substantially improve the confidence in the identification of cross-linked peptides. An MS/MS method termed multiple and sequential data acquisition method (MSDAM) was developed. Preliminary optimization of the MS/MS settings was performed with a synthetic peptide (TP1) cross-linked with bis[sulfosuccinimidyl] suberate (BS(3)). On the basis of these results, MSDAM was created and assessed on the BS(3)-cross-linked bovine serum albumin (BSA) homodimer. MSDAM applies a series of multiple sequential fragmentation events with a range of different normalized collision energies (NCE) to the same precursor ion. The combination of a series of NCE enabled a considerable improvement in the quality of the fragmentation spectra for cross-linked peptides, and ultimately aided in the identification of the sequences of the cross-linked peptides. Concurrently, MSDAM provides confirmatory evidence from the formation of reporter ions fragments, which reduces the false positive rate of incorrectly assigned cross-linked peptides.

  14. Correlation between y-Type Ions Observed in Ion Trap and Triple Quadrupole Mass Spectrometers

    OpenAIRE

    Sherwood, Carly A.; Eastham, Ashley; Lee, Lik Wee; Risler, Jenni; Vitek, Olga; Martin, Daniel B.

    2009-01-01

    Multiple reaction monitoring mass spectrometry (MRM-MS) is a technique for high-sensitivity targeted analysis. In proteomics, MRM-MS can be used to monitor and quantify a peptide based on the production of expected fragment peaks from the selected peptide precursor ion. The choice of which fragment ions to monitor in order to achieve maximum sensitivity in MRM-MS can potentially be guided by existing MS/MS spectra. However, because the majority of discovery experiments are performed on ion tr...

  15. BACH: A Toolset for Bounded Reachability Analysis of Linear Hybrid Systems%BACH:线性混成系统有界可达性模型检验工具

    Institute of Scientific and Technical Information of China (English)

    卜磊; 李游; 王林章; 李宣东

    2011-01-01

    混成自动机的模型检验问题非常困难,即使是其中相对简单的一个子类--线性混成自动机,它的可达性问题仍然是不可判定的.现有的相关工具大都使用多面体计算来判定线性混成自动机状态空间的可达集,复杂度高、效率低,无法解决实际应用规模的问题.描述了一个面向线性混成系统有界可达性模型检验工具--BACH(bounded reachability checker),该工具能够沿指定路径(组)对单个线性混成自动机、多个线性混成自动机的组合进行可达性检验,并且在此基础上结合路径遍历技术完成对所有路径的有界可达性检验.实验数据显示,BACH不仅在面向路径可达性检验方面性能优异,可以适用于足够长度的路径,而且在针对所有路径的有界可达性检验时,BACH可以解决的问题规模也远远超过同类工具,已接近工业界应用的要求.%The model-checking problem for hybrid systems is very difficult to resolve.Even for a relatively simple class of hybrid systems, the class of linear hybrid automata, the most common problem of reachability is unsolvable.Existing techniques for the reachability analysis of linear hybrid automata do not scale well to problem sizes of practical interest.Instead of developing a tool to perform a reachability checking of the complete state space of linear hybrid automata, a prototype toolset BACH (bounded reachability checker) is presented to perform path-oriented reachability checking and bounded reachability checking of the linear hybrid automata and the compositional linear hybrid systems, where the length of the path being checked can be made very large, and the size of the system can be made large enough to handle problems of practical interest.The experiment data shows that BACH has good performance and scalability and supports the fact that BACH can become a powerful assistant for design engineers in the reachability analysis of linear hybrid automata.

  16. Food contaminant analysis at ultra-high mass resolution: application of hybrid linear ion trap - orbitrap mass spectrometry for the determination of the polyether toxins, azaspiracids, in shellfish.

    LENUS (Irish Health Repository)

    2010-10-30

    The biotoxins, azaspiracids (AZAs), from marine phytoplankton accumulate in shellfish and affect human health by causing severe gastrointestinal disturbance, diarrhea, nausea and vomiting. Specific and sensitive methods have been developed and validated for the determination of the most commonly occurring azaspiracid analogs. An LTQ Orbitrap mass spectrometer is a hybrid instrument that combines linear ion trap (LIT) mass spectrometry (MS) with high-resolution Fourier transform (FT) MS and this was exploited to perform simultaneous ultra-high-resolution full-scan MS analysis and collision-induced dissociation (CID) tandem mass spectrometry (MS\\/MS). Using the highest mass resolution setting (100,000 FWHM) in full-scan mode, the methodology was validated for the determination of six AZAs in mussel (Mytilus galloprovincialis) tissue extracts. Ultra-high mass resolution, together with a narrow mass tolerance window of ±2 mDa, dramatically improved detection sensitivity. In addition to employing chromatographic resolution to distinguish between the isomeric azaspiracid analogs, AZA1\\/AZA6 and AZA4\\/AZA5, higher energy collisionally induced dissociation (HCD) fragmentation on selected precursor ions were performed in parallel with full-scan FTMS. Using HCD MS\\/MS, most precursor and product ion masses were determined within 1 ppm of the theoretical m\\/z values throughout the mass spectral range and this enhanced the reliability of analyte identity.For the analysis of mussels (M. galloprovincialis), the method limit of quantitation (LOQ) was 0.010 µg\\/g using full-scan FTMS and this was comparable with the LOQ (0.007 µg\\/g) using CID MS\\/MS. The repeatability data were; intra-day RSD% (1.8-4.4%; n = 6) and inter-day RSD% (4.7-8.6%; n = 3). Application of these methods to the analysis of mussels (M. edulis) that were naturally contaminated with azaspiracids, using high-resolution full-scan Orbitrap MS and low-resolution CID MS\\/MS, produced

  17. Quasi-linearly polarized hybrid modes in tapered and metal-coated tips with circular apertures: understanding the functionality of aperture tips

    Science.gov (United States)

    Tugchin, B. N.; Janunts, N.; Steinert, M.; Dietrich, K.; Kley, E. B.; Tünnermann, A.; Pertsch, T.

    2017-06-01

    In this study, we investigate analytically and experimentally the roles of quasi-linearly polarized (LP), hybrid, plasmonic and photonic modes in optical detection and excitation with aperture tips in scanning near-field optical microscopy. Aperture tips are tapered and metal-coated optical fibers where small circular apertures are made at the apex. In aperture tips, there exist plasmonic modes that are bound at the interface of the metal cladding to the inner dielectric fiber and photonic modes that are guided in the area of the increased index in the dielectric fiber core. The fundamental photonic mode, although excited by the free-space Gaussian beam, experiences cutoff and turns into an evanescent mode. The photonic mode also becomes lossier than the plasmonic mode toward the tip aperture, and its power decay due to absorption and reflection is expected to be at least 10-9. In contrast, the fundamental plasmonic mode has no cutoff and thus reaches all the way to the tip aperture. Due to the non-adiabaticity of both modes’ propagations through the taper below a core radius of 600 nm, there occurs coupling between the modes. The transmission efficiency of the plasmonic mode, including the coupling efficiency and the propagation loss, is expected to be about 10-6 that is at least 3 orders of magnitude larger than that of the photonic mode. Toward the tip aperture, the longitudinal field of the photonic mode becomes stronger than the transverse ones while the transverse fields always dominate for the plasmonic mode. Experimentally, we obtain polarization resolved images of the near-field at the tip aperture and compare with the x- and y-components of the fundamental quasi-LP plasmonic and photonic modes. The results show that not only the pattern but also the intensity ratios of the x- and y-components of the aperture near-field match with that of the fundamental plasmonic mode. Consequently, we conclude that only the plasmonic mode reaches the tip aperture and

  18. Linear equations and rap battles: how students in a wired classroom utilized the computer as a resource to coordinate personal and mathematical positional identities in hybrid spaces

    Science.gov (United States)

    Langer-Osuna, Jennifer

    2015-03-01

    This paper draws on the constructs of hybridity, figured worlds, and cultural capital to examine how a group of African-American students in a technology-driven, project-based algebra classroom utilized the computer as a resource to coordinate personal and mathematical positional identities during group work. Analyses of several vignettes of small group dynamics highlight how hybridity was established as the students engaged in multiple on-task and off-task computer-based activities, each of which drew on different lived experiences and forms of cultural capital. The paper ends with a discussion on how classrooms that make use of student-led collaborative work, and where students are afforded autonomy, have the potential to support the academic engagement of students from historically marginalized communities.

  19. Mechanical Characterization of Hybrid Vesicles Based on Linear Poly(Dimethylsiloxane-b-Ethylene Oxide) and Poly(Butadiene-b-Ethylene Oxide) Block Copolymers

    OpenAIRE

    2016-01-01

    Poly(dimethylsiloxane-ethylene oxide) (PDMS-PEO) and poly(butadiene-b-ethylene oxide) (PBd-PEO) are two block copolymers which separately form vesicles with disparate membrane permeabilities and fluidities. Thus, hybrid vesicles formed from both PDMS-PEO and PBd-PEO may ultimately allow for systematic, application-specific tuning of vesicle membrane fluidity and permeability. However, given the relatively low strength previously noted for comb-type PDMS-PEO vesicles, the mechanical robustness...

  20. High-optical-quality blends of anionic polymethine salts and polycarbonate with enhanced third-order non-linearities for silicon-organic hybrid devices.

    Science.gov (United States)

    Li, Zhong'an; Liu, Yang; Kim, Hyeongeu; Hales, Joel M; Jang, Sei-Hum; Luo, Jingdong; Baehr-Jones, Tom; Hochberg, Michael; Marder, Seth R; Perry, Joseph W; Jen, Alex K-Y

    2012-11-20

    A series of anionic polymethine dyes with different aromatic counterions are prepared to improve their compatibility as guests in an amorphous polycarbonate host. When they are used as the cladding material for silicon hybrid slot waveguides, four-wave mixing wavelength conversion and two-photon absorption-based optical-power modulation are observed. Such guest-host materials may be attractive candidates for all-optical signal-processing applications.

  1. Study of HV Dielectrics for High Frequency Operation in Linear & Nonlinear Transmission Lines & Simulation & Development of Hybrid Nonlinear Lines for RF Generation

    Science.gov (United States)

    2015-08-27

    The high voltage diodes D5 to D10 are used to protect the HV switch against negative back swing voltage, while D4 diode for reverse current ...AFRL-AFOSR-CL-TR-2015-0001 STUDY OF HV DIELECTRICS FOR HIGH FREQUENCY OPERATION IN LINEAR & NONLINEAR TRANSMISSION LINES & SIMULATION & DEVELOPMENT...AFOSR Final Performance Report Study of HV Dielectrics for High Frequency Operation in Linear and Nonlinear Transmission Lines and Simulation

  2. STUDYING GXE INTERACTION UNDER DIFFERENT MANAGEMENT SYSTEM AND YIELD LEVEL USING LINEAR-BILINEAR MODELS: THE CASE OF CIMMYT INTERMEDIATE TO LATE HYBRIDS TRAILS IN EASTERN AFRICA

    Directory of Open Access Journals (Sweden)

    Girma Taye

    2014-08-01

    Full Text Available CIMMYT, with national programs, conducts selection of stress-tolerant genotypes under managed stress conditions; this investigation is expected to add information to the existing knowledge. Data sets used in this study comes from Intermediate to Late Hybrid Trails (ILHT conducted in five Eastern and Central Africa (ECA countries from 2008 to 2011. Trials, ranging from 18 in 2009 to 29 in 2010 were used. Trials are categorized into four management systems and two yield levels. Variance Components, broad sense heritability (H, Site Regression (SREG, Genotypic Regression (GREG, Completely Multiplicative Model (COMM and Factor Analytic (FA models were fitted. Results are discussed and compared with those stated in literature. We argue that it is preferable to first fit the fixed effect models before proceeding to the mixed effect model, as the former shows the level of complexity of the GE component and number of Axis required to explain it. The fixed effect model, SREG2, is preferable for trails targeting to compare hybrids with checks. From the GGE biplots it was noted that the first two PC did not account for sufficient percentage of variation for all years which witnessed complexity in the GE component for this data. Nevertheless, since PC1 accounted for large percentage of variation than PC2, the plot still gives some idea of which hybrids are favored and where. Most importantly, location of genotypes along PC1 can serve for judging yielding potential of the genotypes to guide in selection decision. Equivalence between Finlay – Wilkinson and GREG was established. The few environmental covariables obtained for 2009 was used to fit Partial Least Square (PLS regression. The result indicated complexity in the GE component, as PLS latent factors accounted for small percentage of variation. It was recommended to use information from SREG2, GREG2 and FA(1 models in order to identify stable genotype.

  3. Molecular structure, experimental and theoretical spectroscopic characterization and non-linear optical properties studies of a new non-centrosymmetric hybrid material

    Science.gov (United States)

    Chihaoui, Nejla; Hamdi, Besma; Dammak, Thameur; Zouari, Ridha

    2016-11-01

    This paper gathers the synthesis and study of a novel nonlinear organic-inorganic (1,2-diammoniumcyclohexane tetrabromozincate (II) monohydrate; [C6H10(NH3)2]ZnBr4·H2O) hybrid. The newly developed hybrid was characterized by XRD and spectroscopic (FT-IR, Raman, UV-Visible and CP/MAS-NMR) studies. All theoretical calculations and structural optimization parameters were conducted by using DFT approach with B3LYP/6-31G(d) basis set and the vibrational wavenumbers were evaluated for the affectation of [C6H10(NH3)2]ZnBr4·H2O compound by using transferable scale factor. The inspection of intermolecular links in the studied framework has been executed by the Hirshfeld surface analysis. The nonlinear optical characteristics of this compound were theoretically explored also the molecular orbitals (HOMO) and (LUMO) properties are performed to describe the charge transfer within the crystal.

  4. Structural properties and surface wettability of Cu-containing diamond-like carbon films prepared by a hybrid linear ion beam deposition technique

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Peng; Sun, Lili; Li, Xiaowei [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Xu, Sheng [Gao Hong Coating Technology Co., Ltd, Huzhou 313000 (China); Ke, Peiling [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China); Wang, Aiying, E-mail: aywang@nimte.ac.cn [Key Laboratory of Marine Materials and Related Technologies, Zhejiang Key Laboratory of Marine Materials and Protective Technologies, Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201 (China)

    2015-06-01

    Cu-containing diamond-like carbon (Cu-DLC) films were deposited on Si/glass substrate by a hybrid ion beam deposition system. The Cu concentration (0.1–39.7 at.%) in the film was controlled by varying the sputtering current. The microstructure and composition of Cu-DLC films were investigated systematically. The surface topography, roughness and surface wettability of the films were also studied. Results indicated that with increasing the Cu concentration, the water contact angle of the films changed from 66.8° for pure carbon film to more than 104.4° for Cu-DLC films with Cu concentration larger than 24.4 at.%. In the hydrophilic region, the polar surface energy decreased from 30.54 mJ/m{sup 2} for pure carbon film to 2.48 mJ/m{sup 2} for the film with Cu 7.0 at.%. - Highlights: • Cu-containing diamond-like carbon (DLC) films were deposited by a hybrid ion beam system. • Cu-containing DLC films exhibited a wide range of water contact angle. • The water contact angles vary with the surface energies and surface roughness.

  5. C band predistortion linearizer using a 90° hybrid%采用90°分支电桥的C波段预失真线性化器

    Institute of Scientific and Technical Information of China (English)

    康力; 肖仕伟; 蔡钟斌

    2012-01-01

    为了改善功率放大器的三阶交调失真,提出了一种基于90°分支线电桥的C波段预失真线性化器,使用肖特基二极管产生非线性信号.通过改变线性化器的偏置电压及电容,可调整线性化器的增益扩张和相位延迟特性,与功放级联后对功放的三阶交调失真有改善作用.将该线性化器应用到工作频率为7 GHz,饱和功率为20 dBm的放大器上,在输出功率回退5 dBm处对放大器的三阶交调有10 dBc的改善.%This paper presents a C band predistortion linearizer using a 90° hybrid, which produces nonlinear signal by a Schottky diode, lo modify the distortion caused by the third-order inlermodulation of power amplifier. By changing the bias voltage and the capacitance, the gain expansion and phase shift characteristics of the linearizer can be adjustable. By applying this linearizer lo a 7 GHz-band amplifier with 20 dBm of saturation output power, the linearizer can improve 1MD3 more than 10 dBc when the output power depresses 5 dBm.

  6. Linearization Techniques

    Directory of Open Access Journals (Sweden)

    Gildeberto S. Cardoso

    2011-01-01

    Full Text Available This paper presents a study of linear control systems based on exact feedback linearization and approximate feedback linearization. As exact feedback linearization is applied, a linear controller can perform the control objectives. The approximate feedback linearization is required when a nonlinear system presents a noninvolutive property. It uses a Taylor series expansion in order to compute a nonlinear transformation of coordinates to satisfy the involutivity conditions.

  7. Linear algebra

    CERN Document Server

    Shilov, Georgi E

    1977-01-01

    Covers determinants, linear spaces, systems of linear equations, linear functions of a vector argument, coordinate transformations, the canonical form of the matrix of a linear operator, bilinear and quadratic forms, Euclidean spaces, unitary spaces, quadratic forms in Euclidean and unitary spaces, finite-dimensional space. Problems with hints and answers.

  8. Linear Psoriasis

    Directory of Open Access Journals (Sweden)

    Agarwalla Arun

    2001-01-01

    Full Text Available Linear psoriasis, inflammatory linear varrucous epidermal naevus (ILVEN. Lichen straitus, linear lichen planus and invasion of epidermal naevi by psoriasis have clinical and histopathological overlap. We report two young male patients of true linear psoriasis without classical lesions elsewhere which were proved histopathologically. Seasonal variation and good response to topical antipsoriatic treatment supported the diagnosis.

  9. Proposta de modelagem não-linear do desempenho germinativo de sementes de milho híbrido Nonlinear proposal modeling of seed germination performance of hybrid corn seeds

    Directory of Open Access Journals (Sweden)

    Sebastião Gazola

    2011-04-01

    Full Text Available Este trabalho foi desenvolvido com o objetivo de ajustar um modelo de regressão não-linear para estimar o desempenho germinativo de sementes de três lotes comerciais de milho híbrido OC 705, submetidas ao teste de envelhecimento acelerado, à temperatura de 43ºC. Utilizou-se o modelo logístico y(t=C/(1+exp(B(t-M para ajustar os dados. As medidas de viés de Box e de curvaturas paramétrica e intrínseca foram usadas para o diagnóstico do modelo. O modelo proposto ajusta-se adequadamente aos dados de percentuais germinativos de sementes de milho híbrido OC 705, para todos os lotes. Com base nas estimativas dos parâmetros e qualidade de ajuste, o lote três foi identificado como sendo o melhor para comercialização, por apresentar menor redução no poder germinativo ao longo do tempo.This research was developed with the goal to adjust a nonlinear regression model to estimate seed germination performance of three commercial seed lots of hybrid maize OC 705, subjected to accelerated aging test at a temperature of 43oC. The logistic model y(t=C/(1+exp (B (t-M was used to fit the data. Measures of bias Box and parametric intrinsic bends were used for the diagnosis of the model. The proposed model fits properly to seed germination percentage data of hybrid corn seeds for OC 705, for all seed lots. Based on estimates of the parameters and fit quality, the seed lot three was identified as being the best for marketing, by presenting less reduction in seed germination power over time.

  10. Hybrid Estimation of State and Input for Linear Discrete Time-varying Systems: A Game Theory Approach%线性离散时变系统的状态和输入混合估计:一种对策方法

    Institute of Scientific and Technical Information of China (English)

    尤富强; 王福利; 关守平

    2008-01-01

    The H∞ hybrid estimation problem for linear discrete time-varying systems is investigated in this paper, where estimated signals are linear combination of state and input. Design objective requires the worst-case energy gain from disturbance to estimation error to be less than a prescribed level. Optimal solution of the hybrid estimation problem is the saddle point of a two-player zero sum differential game. On the basis of the differential game approach, necessary and sufficient solvable conditions for the hybrid estimation problem are provided in terms of solutions to a Riccati differential equation. Moreover, one possible estimator is proposed if the solvable conditions are satisfied. The estimator is characterized by a gain matrix and an output mapping matrix, where the latter reflects the internal relations between unknown input and output estimation error. At last, a numerical example is provided to illustrate the proposed approach.

  11. Hybrid inorganic-organic materials: Novel poly(propylene oxide)-based ceramers, abrasion-resistant sol-gel coatings for metals, and epoxy-clay nanocomposites, with an additional chapter on: Metallocene-catalyzed linear polyethylene

    Science.gov (United States)

    Jordens, Kurt

    1999-12-01

    The sol-gel process has been employed to generate hybrid inorganic-organic network materials. Unique ceramers were prepared based on an alkoxysilane functionalized soft organic oligomer, poly(propylene oxide (PPO), and tetramethoxysilane (TMOS). Despite the formation of covalent bonds between the inorganic and organic constituents, the resulting network materials were phase separated, composed of a silicate rich phase embedded in a matrix of the organic oligomer chains. The behavior of such materials was similar to elastomers containing a reinforcing filler. The study focused on the influence of initial oligomer molecular weight, functionality, and tetramethoxysilane, water, and acid catalyst content on the final structure, mechanical and thermal properties. The sol-gel approach has also been exploited to generate thin, transparent, abrasion resistant coatings for metal substrates. These systems were based on alkoxysilane functionalized diethylenetriamine (DETA) with TMOS, which generated hybrid networks with very high crosslink densities. These materials were applied with great success as abrasion resistant coatings to aluminum, copper, brass, and stainless steel. In another study, intercalated polymer-clay nanocomposites were prepared based on various epoxy networks montmorillonite clay. This work explored the influence of incorporated clay on the adhesive properties of the epoxies. The lap shear strength decreased with increasing day content This was due to a reduction in the toughness of the epoxy. Also, the delaminated (or exfoliated) nanocomposite structure could not be generated. Instead, all nanocomposite systems possessed an intercalated structure. The final project involved the characterization of a series of metallocene catalyzed linear polyethylenes, produced at Phillips Petroleum. Polyolefins synthesized with such new catalyst systems are becoming widely available. The influence of molecular weight and thermal treatment on the mechanical, rheological

  12. Rapid screening of drugs of abuse in human urine by high-performance liquid chromatography coupled with high resolution and high mass accuracy hybrid linear ion trap-Orbitrap mass spectrometry.

    Science.gov (United States)

    Li, Xiaowen; Shen, Baohua; Jiang, Zheng; Huang, Yi; Zhuo, Xianyi

    2013-08-09

    A novel analytical toxicology method has been developed for the analysis of drugs of abuse in human urine by using a high resolution and high mass accuracy hybrid linear ion trap-Orbitrap mass spectrometer (LTQ-Orbitrap-MS). This method allows for the detection of different drugs of abuse, including amphetamines, cocaine, opiate alkaloids, cannabinoids, hallucinogens and their metabolites. After solid-phase extraction with Oasis HLB cartridges, spiked urine samples were analysed by HPLC/LTQ-Orbitrap-MS using an electrospray interface in positive ionisation mode, with resolving power of 30,000 full width at half maximum (FWHM). Gradient elution off of a Hypersil Gold PFP column (50mm×2.1mm) allowed to resolve 65 target compounds and 3 internal standards in a total chromatographic run time of 20min. Validation of this method consisted of confirmation of identity, selectivity, linearity, limit of detection (LOD), lowest limits of quantification (LLOQ), accuracy, precision, extraction recovery and matrix effect. The regression coefficients (r(2)) for the calibration curves (LLOQ - 100ng/mL) in the study were ≥0.99. The LODs for 65 validated compounds were better than 5ng/ml except for 4 compounds. The relative standard deviation (RSD), which was used to estimate repeatability at three concentrations, was always less than 15%. The recovery of extraction and matrix effects were above 50 and 70%, respectively. Mass accuracy was always better than 2ppm, corresponding to a maximum mass error of 0.8 millimass units (mmu). The accurate masses of characteristic fragments were obtained by collisional experiments for a more reliable identification of the analytes. Automated data analysis and reporting were performed using ToxID software with an exact mass database. This procedure was then successfully applied to analyse drugs of abuse in a real urine sample from subject who was assumed to be drug addict.

  13. Simultaneous determination of triazine herbicides in rice by high-performance liquid chromatography coupled with high resolution and high mass accuracy hybrid linear ion trap-orbitrap mass spectrometry.

    Science.gov (United States)

    Mou, Ren-Xiang; Chen, Ming-Xue; Cao, Zhao-Yun; Zhu, Zhi-Wei

    2011-11-07

    A method was developed for the simultaneous determination of 10 triazine herbicides (cyanazine, simazine, simetryn, metribuzin, atrazine, ametryn, terbuthylazine, prometryn, terbutryn, and dimethametryn) in rice samples by high resolution and high mass accuracy hybrid linear ion trap-Orbitrap mass spectrometer. After extraction with acetonitrile and evaporation, the herbicides were redissolved in n-hexane and purified on a Florisil solid-phase extraction column. All compounds were separated within 12 min, producing more than 11 data points for each herbicide and high mass accuracy quantified ions which the mass errors of absolute value were less than 1.9 ppm in pure solution and 2.1 ppm in the matrix-matched standards solution. The method was validated in terms of the limits of detection and the limits of quantification. The linearity was satisfactory, with a correlation coefficient of >0.9975. Precision and recovery studies were evaluated at three concentration levels for Japonica, Indica, and Glutinous rice matrix. The mean recoveries obtained for all analytes in spiked Xiushui 03, Liangyoupeijiu, and Taihunuo rice samples were 83.3-99.0%, 82.0-99.7%, and 84.2-99.4%, respectively, with relative standard deviation in range 1.7-10.6%, 1.2-10.7%, and 1.9-11.6% for spiked rice samples, respectively. The intra-day precision (n=5) for the 10 herbicides in rice samples spiked at an intermediate level was between 2.8% and 7.9%, and the inter-day precision over 10 days (n=10) was between 5.5% and 15.9%.

  14. Synthesis, X-ray crystal structure and highly non-linear optical properties of inorganic-organic hybrid compound: 1,4-Diazbicyclo-octane oxonium tri- nitrates single crystal

    Science.gov (United States)

    Henchiri, Rokaya; Ennaceur, Nasreddine; Cordier, Marie; Ledoux-Rak, Isabelle; Elaloui, Elimame

    2017-07-01

    A new nonlinear optical hybrid crystal 1,4-Diazbicyclo[222]octane oxonium tri-nitrates (DOTN), of the dimension 4×12×1 mm3. The crystal was grown using water as solvent at room temperature and crystal structure was determined by X-Ray diffraction respectively, this title compound was shown to crystallize in non-centrosymmetric trigonal system with space group P31c. The recorded FTIR spectrum has proven the presence of various functional groups in the grown crystal as well as the formation of DOTN. Besides, the thermal stability and melting temperature of the DOTN crystal were identified from the TG/DSC analysis. The suitability of this material for optical application was studied by non-linear optical (NLO) and UV-visible absorption techniques. Furthermore, the nonlinear optical property was analyzed by Kurtz-Perry powder technique and was 3.4 times than that of KDP (potassium dihydrogen phosphate) single crystals. The first hyperpolarizability of nitrate was determined by Second Harmonic light Scattering.

  15. Characterization and identification of the chemical constituents from tartary buckwheat (Fagopyrum tataricum Gaertn) by high performance liquid chromatography/photodiode array detector/linear ion trap FTICR hybrid mass spectrometry.

    Science.gov (United States)

    Ren, Qiang; Wu, Caisheng; Ren, Yan; Zhang, Jinlan

    2013-02-15

    In recent years tartary buckwheat has become popular healthful food due to its antioxidant, antidiabetic and antitumor activities. However, its chemical constituents have not yet been fully characterized and identified. In this paper, a novel high performance liquid chromatography coupled with photodiode array detector and linear ion trap FTICR hybrid mass spectrometry (HPLC-PDA/LTQ-FTICRMS) method was established to characterize and identify a total of 36 compounds by a single run. The retention time, maximum UV absorption wavelength, accurate mass weight and characteristic fragment ions were collected on line. To confirm the structures, 11 compounds were isolated and identified by MS and NMR experiments. 1, 3, 6, 6'-tetra-feruloyl sucrose named taroside was a new phenlypropanoid glycoside, together with 3, 6-di-p-coumaroyl-1, 6'-di-feruloyl sucrose, 1, 6, 6'-tri-feruloyl-3-p-coumaroyl sucrose, N-trans-feruloyltyramine and quercetin-3-O-[β-D-xyloxyl-(1→2)-α-L-rhamnoside] were isolated for the first time from the Fagopyrum species. The research enriched the chemical information of tartary buckwheat.

  16. Evaluation of Top-Cross Popcorn Hybrids Using Mixed Linear Model Methodology Evaluación de Híbridos Top-Cross de Maíz-Roseta Usando Modelos Lineales Mixtos

    Directory of Open Access Journals (Sweden)

    Emmanuel Arnhold

    2009-03-01

    Full Text Available The market for popcorn (Zea mays L. has been continuously growing in Brazil fact has required the development of cultivars adapted to local environmental conditions. For this reason, the analytical objectives of this study were to evaluate top-cross popcorn hybrids in relation to popping expansion and grain yield in three different eco-geographic regions of Brazil, in order to estimate variance components using Restricted Maximum Likelihood (REML and predict breeding values using Best Linear Unbiased Prediction (BLUP. Genetic evaluation considered a linear model with heterogeneous residual (environmental variances. The Restricted Likelihood Ratio Test (RLRT evidenced significant differences (p Evaluación de híbridos top-cross de maíz-roseta usando modelos lineales mixtos. El mercado del maíz-roseta (Zea mays L. está en continuo crecimiento en Brasil, lo cual ha demandado el desarrollo de cultivares adaptados a las condiciones locales. Por ello, los objetivos del presente trabajo fueron evaluar híbridos top-cross de maíz-roseta en función de la capacidad de expansión y el rendimiento de los granos, en diferentes regiones eco-geográficas de Brasil; estimar componentes de varianza usando Máxima Verosimilitud Restringida (REML y predecir los valores genotípicos a través de la Mejor Predicción Linear Insesgada (BLUP. La evaluación genética consideró un modelo lineal con una estructura de varianza residual (ambiental heterogénea. La prueba de la razón de verosimilitud (restringida evidenció diferencias significativas (p < 0,01 para el efecto genotípico. La producción de granos mostró ser una característica de heredabilidad media (h² = 0,26-0,39. En la capacidad de expansión se evidenció un mayor control genético aditivo (h² = 0,58-0,85. Las correlaciones genéticas y de Spearman entre las características fueron negativas, indicando que la selección basada en el rendimiento de granos tendría un efecto negativo sobre la

  17. Analog and hybrid computing

    CERN Document Server

    Hyndman, D E

    2013-01-01

    Analog and Hybrid Computing focuses on the operations of analog and hybrid computers. The book first outlines the history of computing devices that influenced the creation of analog and digital computers. The types of problems to be solved on computers, computing systems, and digital computers are discussed. The text looks at the theory and operation of electronic analog computers, including linear and non-linear computing units and use of analog computers as operational amplifiers. The monograph examines the preparation of problems to be deciphered on computers. Flow diagrams, methods of ampl

  18. Analysis of Linear Hybrid Systems in CLP

    DEFF Research Database (Denmark)

    Banda, Gourinath; Gallagher, John Patrick

    2009-01-01

    notation for specifying real-time systems. The main contributions are (i) a technique for capturing the reachable states of the continuously changing state variables of the LHA as CLP constraints; (ii) a way of representing events in the LHA as constraints in CLP, along with a product construction...... and argue that we contribute to the general field of using static analysis tools for verification...

  19. Liquid Chromatography - Triple Quadrupole Mass Spectrometry : The gold standard for quantitative bioanalysis of anti-cancer agents

    NARCIS (Netherlands)

    Vainchtein, L.D.

    2008-01-01

    To understand the pharmacologic mechanisms of action, efficacy and toxicity of any anti-cancer drug it is important to know how the compound is transformed in the body: either into active metabolites or inactive and toxic (degradation) products. This information may lead to the success or failure of

  20. Formation of solvated ions in the atmospheric interface of an electrospray ionization triple-quadrupole mass spectrometer.

    Science.gov (United States)

    Schlosser, Gitta; Takáts, Zoltán; Vékey, Károly

    2003-12-01

    A simple method capable of generating and investigating various solvent clusters and solvated ions was developed. The technique opens a door to studying these complexes on commercially available instruments. Formation of the desired solvated ion in the gas phase was achieved by introducing the appropriate volatile solvent vapour into the curtain gas stream. Capabilities of the technique are illustrated by generating alkali, alkaline earth and transition metal cations solvated by various volatile compounds such as water, methanol and acetonitrile. Depending on the ligands and on the experimental conditions, clusters of 2-100 molecules may be observed. Isotope labelling suggests that these are formed by a re-solvation process in the curtain gas region.

  1. Determination of deoxynivalenol in wheat-based snacks by gas chromatography-triple quadrupole tandem mass spectrometry

    Directory of Open Access Journals (Sweden)

    Y. Rodríguez-Carrasco

    2013-01-01

    Full Text Available El deoxinivalenol (DON es la micotoxina producida por hongos del género Fusarium que con más frecuencia se detecta en cereales y productos a base de cereales. Por ello, es recomendable realizar una continua monitorización de su incidencia en los alimentos. Este trabajo propone un procedimiento analítico basado en una extracción tipo QuEChERS seguido de una cromatografía de gases acoplada a un detector de triple cuadrupolo para la determinación de DON en rosquilletas. Se analizaron un total de 40 muestras las cuales se dividieron según su composición en dos grupos. El DON fue identificado en el 67,5% de las muestras analizadas con un contenido máximo de 61 μg/kg. A pesar de su incidencia elevada, los niveles de DON hallados fueron muy inferiores a los límites máximos legislados en la actual legislación europea (500 μg/kg. Los resultados obtenidos muestran una baja exposición a DON a través del consumo de esta matriz alimentaria.

  2. Application of MALDI-triple quadrupole mass spectrometry for the quantification of small molecules in biomedical research

    NARCIS (Netherlands)

    R.J.W. Meesters (Roland)

    2011-01-01

    textabstractA century after its introduction, mass spectrometry is still an innovative technology, which, due to continuous instrumental developments and improvements, has provided important scientific insights in biochemistry, molecular biology and medicine. Now, in 2011, mass spectrometry is used

  3. Method development for liquid chromatographic/triple quadrupole mass spectrometric analysis of trace level perfluorocarboxylic acids in articles of commerce

    Science.gov (United States)

    An analytical method to identify and quantify trace levels of C5 to C12 perfluorocarboxylic acids (PFCAs) in articles of commerce (AOC) is developed and rigorously validated. Solid samples were extracted in methanol, and liquid samples were diluted with a solvent consisting of 60...

  4. Application of MALDI-triple quadrupole mass spectrometry for the quantification of small molecules in biomedical research

    NARCIS (Netherlands)

    R.J.W. Meesters (Roland)

    2011-01-01

    textabstractA century after its introduction, mass spectrometry is still an innovative technology, which, due to continuous instrumental developments and improvements, has provided important scientific insights in biochemistry, molecular biology and medicine. Now, in 2011, mass spectrometry is used

  5. Linear Systems.

    Science.gov (United States)

    The report documents a series of seminars at Rome Air Development Center with the content equivalent to an intense course in Linear Systems . Material...is slanted toward the practicing engineer and introduces some of the fundamental concepts and techniques for analyzing linear systems . Techniques for

  6. Hybrid Baryons

    CERN Document Server

    Page, P R

    2003-01-01

    We review the status of hybrid baryons. The only known way to study hybrids rigorously is via excited adiabatic potentials. Hybrids can be modelled by both the bag and flux-tube models. The low-lying hybrid baryon is N 1/2^+ with a mass of 1.5-1.8 GeV. Hybrid baryons can be produced in the glue-rich processes of diffractive gamma N and pi N production, Psi decays and p pbar annihilation.

  7. Linear algebra

    CERN Document Server

    Stoll, R R

    1968-01-01

    Linear Algebra is intended to be used as a text for a one-semester course in linear algebra at the undergraduate level. The treatment of the subject will be both useful to students of mathematics and those interested primarily in applications of the theory. The major prerequisite for mastering the material is the readiness of the student to reason abstractly. Specifically, this calls for an understanding of the fact that axioms are assumptions and that theorems are logical consequences of one or more axioms. Familiarity with calculus and linear differential equations is required for understand

  8. 线性连续时变系统的状态和输入混合估计:一种对策方法%Hybrid Estimation of State and Input for Linear Continuous Time-varying Systems: A Game Theory Approach

    Institute of Scientific and Technical Information of China (English)

    杨晓军; 翁正新; 田作华; 施颂椒

    2005-01-01

    The H∞ hybrid estimation problem for linear continuous time-varying systems is investigated in this paper, where estimated signals are linear combination of state and input. Design objective requires the worst-case energy gain from disturbance to estimation error be less than a prescribed level. Optimal solution of the hybrid estimation problem is the saddle point of a two-player zero sum differential game. Based on the differential game approach, necessary and sufficient solvable conditions for the hybrid estimation problem are provided in terms of solutions to a Riccati differential equation. Moreover, one possible estimator is proposed if the solvable conditions are satisfied.The estimator is characterized by a gain matrix and an output mapping matrix that reflects the internal relations between the unknown input and output estimation error. Both state and unknown inputs estimation are realized by the proposed estimator. Thus, the results in this paper are also capable of dealing with fault diagnosis problems of linear time-varying systems. At last, a numerical example is provided to illustrate the proposed approach.

  9. Linear Models

    CERN Document Server

    Searle, Shayle R

    2012-01-01

    This 1971 classic on linear models is once again available--as a Wiley Classics Library Edition. It features material that can be understood by any statistician who understands matrix algebra and basic statistical methods.

  10. Linear programming

    CERN Document Server

    Solow, Daniel

    2014-01-01

    This text covers the basic theory and computation for a first course in linear programming, including substantial material on mathematical proof techniques and sophisticated computation methods. Includes Appendix on using Excel. 1984 edition.

  11. Linear algebra

    CERN Document Server

    Berberian, Sterling K

    2014-01-01

    Introductory treatment covers basic theory of vector spaces and linear maps - dimension, determinants, eigenvalues, and eigenvectors - plus more advanced topics such as the study of canonical forms for matrices. 1992 edition.

  12. Linear algebra

    CERN Document Server

    Liesen, Jörg

    2015-01-01

    This self-contained textbook takes a matrix-oriented approach to linear algebra and presents a complete theory, including all details and proofs, culminating in the Jordan canonical form and its proof. Throughout the development, the applicability of the results is highlighted. Additionally, the book presents special topics from applied linear algebra including matrix functions, the singular value decomposition, the Kronecker product and linear matrix equations. The matrix-oriented approach to linear algebra leads to a better intuition and a deeper understanding of the abstract concepts, and therefore simplifies their use in real world applications. Some of these applications are presented in detailed examples. In several ‘MATLAB-Minutes’ students can comprehend the concepts and results using computational experiments. Necessary basics for the use of MATLAB are presented in a short introduction. Students can also actively work with the material and practice their mathematical skills in more than 300 exerc...

  13. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    Stohlgren, Thomas J.; Szalanski, Allen L; Gaskin, John F.; Young, Nicholas E.; West, Amanda; Jarnevich, Catherine S.; Tripodi, Amber

    2015-01-01

    Science has shown that the introgression or hybridization of modern humans (Homo sapiens) with Neanderthals up to 40,000 YBP may have led to the swarm of modern humans on earth. However, there is little doubt that modern trade and transportation in support of the humans has continued to introduce additional species, genotypes, and hybrids to every country on the globe. We assessed the utility of species distributions modeling of genotypes to assess the risk of current and future invaders. We evaluated 93 locations of the genus Tamarix for which genetic data were available. Maxent models of habitat suitability showed that the hybrid, T. ramosissima x T. chinensis, was slightly greater than the parent taxa (AUCs > 0.83). General linear models of Africanized honey bees, a hybrid cross of Tanzanian Apis mellifera scutellata and a variety of European honey bee including A. m. ligustica, showed that the Africanized bees (AUC = 0.81) may be displacing European honey bees (AUC > 0.76) over large areas of the southwestern U.S. More important, Maxent modeling of sub-populations (A1 and A26 mitotypes based on mDNA) could be accurately modeled (AUC > 0.9), and they responded differently to environmental drivers. This suggests that rapid evolutionary change may be underway in the Africanized bees, allowing the bees to spread into new areas and extending their total range. Protecting native species and ecosystems may benefit from risk maps of harmful invasive species, hybrids, and genotypes.

  14. Linear regression

    CERN Document Server

    Olive, David J

    2017-01-01

    This text covers both multiple linear regression and some experimental design models. The text uses the response plot to visualize the model and to detect outliers, does not assume that the error distribution has a known parametric distribution, develops prediction intervals that work when the error distribution is unknown, suggests bootstrap hypothesis tests that may be useful for inference after variable selection, and develops prediction regions and large sample theory for the multivariate linear regression model that has m response variables. A relationship between multivariate prediction regions and confidence regions provides a simple way to bootstrap confidence regions. These confidence regions often provide a practical method for testing hypotheses. There is also a chapter on generalized linear models and generalized additive models. There are many R functions to produce response and residual plots, to simulate prediction intervals and hypothesis tests, to detect outliers, and to choose response trans...

  15. Linear algebra

    CERN Document Server

    Sahai, Vivek

    2013-01-01

    Beginning with the basic concepts of vector spaces such as linear independence, basis and dimension, quotient space, linear transformation and duality with an exposition of the theory of linear operators on a finite dimensional vector space, this book includes the concept of eigenvalues and eigenvectors, diagonalization, triangulation and Jordan and rational canonical forms. Inner product spaces which cover finite dimensional spectral theory and an elementary theory of bilinear forms are also discussed. This new edition of the book incorporates the rich feedback of its readers. We have added new subject matter in the text to make the book more comprehensive. Many new examples have been discussed to illustrate the text. More exercises have been included. We have taken care to arrange the exercises in increasing order of difficulty. There is now a new section of hints for almost all exercises, except those which are straightforward, to enhance their importance for individual study and for classroom use.

  16. Linear algebra

    CERN Document Server

    Edwards, Harold M

    1995-01-01

    In his new undergraduate textbook, Harold M Edwards proposes a radically new and thoroughly algorithmic approach to linear algebra Originally inspired by the constructive philosophy of mathematics championed in the 19th century by Leopold Kronecker, the approach is well suited to students in the computer-dominated late 20th century Each proof is an algorithm described in English that can be translated into the computer language the class is using and put to work solving problems and generating new examples, making the study of linear algebra a truly interactive experience Designed for a one-semester course, this text adopts an algorithmic approach to linear algebra giving the student many examples to work through and copious exercises to test their skills and extend their knowledge of the subject Students at all levels will find much interactive instruction in this text while teachers will find stimulating examples and methods of approach to the subject

  17. Linear algebra

    CERN Document Server

    Allenby, Reg

    1995-01-01

    As the basis of equations (and therefore problem-solving), linear algebra is the most widely taught sub-division of pure mathematics. Dr Allenby has used his experience of teaching linear algebra to write a lively book on the subject that includes historical information about the founders of the subject as well as giving a basic introduction to the mathematics undergraduate. The whole text has been written in a connected way with ideas introduced as they occur naturally. As with the other books in the series, there are many worked examples.Solutions to the exercises are available onlin

  18. VLSI Hybrid DC-DC Regulator

    OpenAIRE

    Cosp Vilella, Jordi; Martínez García, Herminio

    2015-01-01

    Hybrid DC-DC regulators are structures that combine both a linear voltage regulator and a switching DC-DC converter. The main objective of this hybrid topology is to converge, in a single circuit topology, the best of both alternatives: a small voltage output ripple, which is a common characteristic of linear regulator circuits, and good energy efficiency, as in switching alternatives. While the linear regulator fixes the required output voltage to a fixed value with negligible steady-state r...

  19. Hybrid vehicles

    Energy Technology Data Exchange (ETDEWEB)

    West, J.G.W. [Electrical Machines (United Kingdom)

    1997-07-01

    The reasons for adopting hybrid vehicles result mainly from the lack of adequate range from electric vehicles at an acceptable cost. Hybrids can offer significant improvements in emissions and fuel economy. Series and parallel hybrids are compared. A combination of series and parallel operation would be the ideal. This can be obtained using a planetary gearbox as a power split device allowing a small generator to transfer power to the propulsion motor giving the effect of a CVT. It allows the engine to run at semi-constant speed giving better fuel economy and reduced emissions. Hybrid car developments are described that show the wide range of possible hybrid systems. (author)

  20. Linear programming

    CERN Document Server

    Karloff, Howard

    1991-01-01

    To this reviewer’s knowledge, this is the first book accessible to the upper division undergraduate or beginning graduate student that surveys linear programming from the Simplex Method…via the Ellipsoid algorithm to Karmarkar’s algorithm. Moreover, its point of view is algorithmic and thus it provides both a history and a case history of work in complexity theory. The presentation is admirable; Karloff's style is informal (even humorous at times) without sacrificing anything necessary for understanding. Diagrams (including horizontal brackets that group terms) aid in providing clarity. The end-of-chapter notes are helpful...Recommended highly for acquisition, since it is not only a textbook, but can also be used for independent reading and study. —Choice Reviews The reader will be well served by reading the monograph from cover to cover. The author succeeds in providing a concise, readable, understandable introduction to modern linear programming. —Mathematics of Computing This is a textbook intend...

  1. Linear systems

    CERN Document Server

    Bourlès, Henri

    2013-01-01

    Linear systems have all the necessary elements (modeling, identification, analysis and control), from an educational point of view, to help us understand the discipline of automation and apply it efficiently. This book is progressive and organized in such a way that different levels of readership are possible. It is addressed both to beginners and those with a good understanding of automation wishing to enhance their knowledge on the subject. The theory is rigorously developed and illustrated by numerous examples which can be reproduced with the help of appropriate computation software. 60 exe

  2. On Fractional Order Hybrid Differential Equations

    Directory of Open Access Journals (Sweden)

    Mohamed A. E. Herzallah

    2014-01-01

    Full Text Available We develop the theory of fractional hybrid differential equations with linear and nonlinear perturbations involving the Caputo fractional derivative of order 0<α<1. Using some fixed point theorems we prove the existence of mild solutions for two types of hybrid equations. Examples are given to illustrate the obtained results.

  3. The nature of solutions to linear passive complementarity systems

    NARCIS (Netherlands)

    Camlibel, Mehmet; Heemels, W.P.M.H.; Schumacher, J.M.

    1999-01-01

    Linear passive systems with complementarity conditions (as an application, one may consider linear passive networks with ideal diodes) are studied. For these systems contained in the linear complementarity class of hybrid systems, existence and uniqueness of solutions are established. Moreover, the

  4. Hybrid Metaheuristics

    CERN Document Server

    2013-01-01

    The main goal of this book is to provide a state of the art of hybrid metaheuristics. The book provides a complete background that enables readers to design and implement hybrid metaheuristics to solve complex optimization problems (continuous/discrete, mono-objective/multi-objective, optimization under uncertainty) in a diverse range of application domains. Readers learn to solve large scale problems quickly and efficiently combining metaheuristics with complementary metaheuristics, mathematical programming, constraint programming and machine learning. Numerous real-world examples of problems and solutions demonstrate how hybrid metaheuristics are applied in such fields as networks, logistics and transportation, bio-medical, engineering design, scheduling.

  5. LINEAR SYSTEMS AND LINEAR INTERPOLATION I

    Institute of Scientific and Technical Information of China (English)

    丁立峰

    2001-01-01

    he linear interpolation of linear system on a family of linear systems is introduced and discussed. Some results and examples on singly generated systems on a finite dimensional vector space are given.

  6. Hybrid intermediaries

    OpenAIRE

    Cetorelli, Nicola

    2014-01-01

    I introduce the concept of hybrid intermediaries: financial conglomerates that control a multiplicity of entity types active in the "assembly line" process of modern financial intermediation, a system that has become known as shadow banking. The complex bank holding companies of today are the best example of hybrid intermediaries, but I argue that financial firms from the "nonbank" space can just as easily evolve into conglomerates with similar organizational structure, thus acquiring the cap...

  7. Hybrid composites

    CSIR Research Space (South Africa)

    Jacob John, Maya

    2009-04-01

    Full Text Available effect was observed for the elongation at break of the hybrid composites. The impact strength of the hybrid composites increased with the addition of glass fibres. The tensile and impact properties of thermoplastic natural rubber reinforced short... panels made from conventional structural materials. Figure 3 illustrates the performance of cellular biocomposite panels against conventional systems used for building and residential construction, namely a pre- cast pre-stressed hollow core concrete...

  8. Bounded hybrid superiority in an avian hybrid zone: effects of mate, diet, and habitat choice.

    Science.gov (United States)

    Good, T P; Ellis, J C; Annett, C A; Pierotti, R

    2000-10-01

    There has been considerable debate in the study of hybrid zones as to whether hybrids may be superior to parental types within the area of contact (bounded hybrid superiority). In birds, naturally occurring hybridization is relatively common, and hybridization within this group always involves mate choice. If hybrids are superior, females choosing heterospecific mates should be expected to show higher fitness under the conditions prevalent in the hybrid zone. Hybrid superiority under these circumstances would reduce reinforcement and thereby help to maintain the hybrid zone. To examine this issue, we studied reproductive performances of hybrids and parental species of gulls (Larus occidentalis and Larus glaucescens) at two colonies within a linear hybrid zone along the west coast of the United States. This hybrid zone contains predominantly gulls of intermediate phenotype. Previous studies indicated that hybrids were superior to one or both parental types, but provided no data on possible mechanisms that underlie this hybrid superiority. Using a hybrid index designed specifically for these species, we identified to phenotype more than 300 individuals associated with nests, including both individual males and females within 73 pairs in the central portion of the hybrid zone and 74 pairs in the northern portion of the hybrid zone. There was little evidence of assortative mating, and what little there was resulted solely because of pairings within intergrades. In the central hybrid zone, females paired with hybrid males produced larger clutches and hatched and fledged more chicks compared with females paired to western gull males. This was a result of heavy predation on eggs in sand habitat, where male western gulls established territories. In contrast, many hybrid males established territories in vegetated cover that was less vulnerable to predation. In the northern part of the hybrid zone, clutch size did not differ among pair categories, however, there were

  9. 计及非线性因素的混合供能系统协调控制%Coordinated Control of Hybrid Power Supply Systems Considering Non-linear Factors

    Institute of Scientific and Technical Information of China (English)

    郭力; 李霞林; 王成山

    2012-01-01

    The hybrid power supply system with its renewable energy generation units and energy storage devices integrated through a common DC bus can effectively improve the utilization and control flexibility of distributed generations. In this paper, a hybrid system containing lithium battery energy storage system, ultra-capacitors and PV was considered. After a brief description of two basic operation modes and DC-bus voltage control strategies of the system, the mechanism of the DC bus voltage transient impact in different control mode had been analysed via theoretical and experimental methods. Consequently, the solutions such as dead time compensation and the steady state duty cycle control signal compensation had been proposed, which eventually validated on the hybrid system based on a 30 kVA two-stage power converter.%通过公共直流母线集成可再生能源发电单元和储能设备等的混合供能系统,可以有效提高分布式电源的利用率和控制灵活性.该文针对包含锂电池、超级电容器及光伏的混合供能系统,介绍了该系统的2种基本运行模式及直流母线电压控制方式,并对不同运行模式下暂态时直流母线电压冲击产生的机理进行了理论和实验分析,提出了分别采用死区补偿及稳态占空比控制信号补偿等解决措施.在基于30 kVA双级式变流器的混合供能系统实验平台中验证了该文所提方法的有效性.

  10. Linear Algebra and Smarandache Linear Algebra

    OpenAIRE

    Vasantha, Kandasamy

    2003-01-01

    The present book, on Smarandache linear algebra, not only studies the Smarandache analogues of linear algebra and its applications, it also aims to bridge the need for new research topics pertaining to linear algebra, purely in the algebraic sense. We have introduced Smarandache semilinear algebra, Smarandache bilinear algebra and Smarandache anti-linear algebra and their fuzzy equivalents. Moreover, in this book, we have brought out the study of linear algebra and ve...

  11. Linear Algebra and Smarandache Linear Algebra

    OpenAIRE

    Vasantha, Kandasamy

    2003-01-01

    The present book, on Smarandache linear algebra, not only studies the Smarandache analogues of linear algebra and its applications, it also aims to bridge the need for new research topics pertaining to linear algebra, purely in the algebraic sense. We have introduced Smarandache semilinear algebra, Smarandache bilinear algebra and Smarandache anti-linear algebra and their fuzzy equivalents. Moreover, in this book, we have brought out the study of linear algebra and ve...

  12. Development of a Hybrid Photopolymer for Stereolithography

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    New liquid free radical-cationic hybrid photopolymer, consisting of acrylate-based photocurable resin and epoxy-based photosensitive resin for stereolithography by UV laser was developed.The experiment results indicated that the hybrid photopolymer exhibits advantages of both the acrylate- based photosensitive resin and the epoxy- based photosensitive polymer contained in the hybrid system with relatively high photospeed and low linear shrinkage.Stereolithography parts without obvious distortion were built on the stereolithography apparatus HRPLAI from this hybrid resin successfully and efficiently.

  13. Natural co-occurrence of mycotoxins in wheat grains from Italy and Syria.

    Science.gov (United States)

    Alkadri, D; Rubert, J; Prodi, A; Pisi, A; Mañes, J; Soler, C

    2014-08-15

    This article describes the application of an analytical method for the detection of 25 mycotoxins in wheat grain based on simultaneous extraction using matrix solid-phase dispersion (MSPD) followed by liquid chromatography coupled to tandem mass spectrometry, a hybrid triple quadrupole-linear ion trap mass spectrometer (QTrap®). Information Dependent Acquisition (IDA), an extra confirmation tool for samples that contain the target mycotoxins, was used. The analysis of 40 Syrian and 46 Italian wheat grain samples interestingly showed that Syrian samples were mainly contaminated with ochratoxin A and aflatoxins, whereas Italian samples with deoxynivalenol and 15-acetyldeoxynivalenol. Emerging Fusarium mycotoxins were predominant in Italian samples compared to the Syrian. Among the analysed samples, only one was found containing zeralenone with level above the maximum European recommended concentration (100 ppb). These results confirm that climatic differences between Syria and Italy, both in Mediterranean basin, play a key role in the diversity of fungal genera and mycotoxins in wheat grains.

  14. Limit Cycle Analysis in a Class of Hybrid Systems

    Directory of Open Access Journals (Sweden)

    Antonio Favela-Contreras

    2016-01-01

    Full Text Available Hybrid systems are those that inherently combine discrete and continuous dynamics. This paper considers the hybrid system model to be an extension of the discrete automata associating a continuous evolution with each discrete state. This model is called the hybrid automaton. In this work, we achieve a mathematical formulation of the steady state and we show a way to obtain the initial conditions region to reach a specific limit cycle for a class of uncoupled and coupled continuous-linear hybrid systems. The continuous-linear term is used in the sense of the system theory and, in this sense, continuous-linear hybrid automata will be defined. Thus, some properties and theorems that govern the hybrid automata dynamic behavior to evaluate a limit cycle existence have been established; this content is explained under a theoretical framework.

  15. Linearly constrained minimax optimization

    DEFF Research Database (Denmark)

    Madsen, Kaj; Schjær-Jacobsen, Hans

    1978-01-01

    We present an algorithm for nonlinear minimax optimization subject to linear equality and inequality constraints which requires first order partial derivatives. The algorithm is based on successive linear approximations to the functions defining the problem. The resulting linear subproblems...

  16. STABILITY OF A SWITCHED LINEAR SYSTEM

    Directory of Open Access Journals (Sweden)

    At-Tasneem Mohd Amin

    2012-12-01

    Full Text Available Hybrid systems are dynamic systems that arise out of the interaction of continuous state dynamics and discrete state dynamics. Switched systems, which are a type of hybrid system, have been given much attention by control systems research over the past decade. Problems with the controllability, observability, converseability and stabilizability of switched systems have always been discussed. In this paper, the trend in research regarding the stability of switched systems will be investigated. Then the variety of methods that have been discovered by researchers for stabilizing switched linear systems with arbitrary switching will be discussed in detail.

  17. Ultra-high performance liquid chromatography with linear ion trap-Orbitrap hybrid mass spectrometry combined with a systematic strategy based on fragment ions for the rapid separation and characterization of components in Stellera chamaejasme extracts.

    Science.gov (United States)

    Wang, Zhixin; Qu, Yang; Wang, Li; Zhang, Xiaozhe; Xiao, Hongbin

    2016-04-01

    Stellera chamaejasme, a famous toxic herb, has been used in traditional Chinese medicine to treat various diseases. For decades, increasing attention in modern pharmacological studies has been drawn to S. chamaejasme because of its potential anti-tumor, anti-virus, and anti-fungus activities. However, due to the intrinsic complexity of chemical constitutes, hardly any investigations formed an overall recognition for the chemical profiles of this herb. In this study, a rapid and sensitive ultra-high performance liquid chromatography coupled with linear ion trap-Orbitrap mass spectrometry method was developed to characterize the chemical components of S. chamaejasme extracts. Based on optimized ultra-high performance liquid chromatography and mass spectrometry conditions and systematic fragment ions-based strategy, a total of 47 components including flavones, diterpenes, coumarins, and lignans were simultaneously detected and identified or tentatively identified for the first time. The MS(n) fragmentation patterns of all the characterized compounds in positive or negative electrospray ionization modes were also explored and summarized. These results provided essential data for further pharmacological research on S. chamaejasme. Moreover, the method was demonstrated to be an efficient tool for rapid qualitative analysis of secondary metabolites from natural resources.

  18. Model Reduction of Hybrid Systems

    DEFF Research Database (Denmark)

    Shaker, Hamid Reza

    systems are derived in this thesis. The results are used for output feedback control of switched nonlinear systems. Model reduction of piecewise affine systems is also studied in this thesis. The proposed method is based on the reduction of linear subsystems inside the polytopes. The methods which......High-Technological solutions of today are characterized by complex dynamical models. A lot of these models have inherent hybrid/switching structure. Hybrid/switched systems are powerful models for distributed embedded systems design where discrete controls are applied to continuous processes...... of hybrid systems, designing controllers and implementations is very high so that the use of these models is limited in applications where the size of the state space is large. To cope with complexity, model reduction is a powerful technique. This thesis presents methods for model reduction and stability...

  19. Hybrid microelectronic technology

    Science.gov (United States)

    Moran, P.

    Various areas of hybrid microelectronic technology are discussed. The topics addressed include: basic thick film processing, thick film pastes and substrates, add-on components and attachment methods, thin film processing, and design of thick film hybrid circuits. Also considered are: packaging hybrid circuits, automating the production of hybrid circuits, application of hybrid techniques, customer's view of hybrid technology, and quality control and assurance in hybrid circuit production.

  20. DFT(B3LYP/LanL2DZ), non-linear optical and electrical studies of a new hybrid compound: [C6H10(NH3)2]CoCl4·H2O

    Science.gov (United States)

    Tounsi, Amal; Hamdi, Besma; Zouari, Ridha; Ben Salah, Abdelhamid

    2016-10-01

    A new organic-inorganic material [C6H10(NH3)2]CoCl4·H2O was reported. The title compound was synthesized at room temperature by slow evaporation and then characterized by a single X-ray diffraction, spectroscopic measurements, thermal analysis and dielectric technique. It crystallizes in the non-centrosymmetric space group Pna21 with the following unit cell parameters: a=12.5328(1) Å, b=9.0908(1) Å, c=11.7440(1) and α=β=γ=90°. The structure can be described by the alternation of two different cationic-anionic layers. It consists of isolated H2O, isolated [CoCl4]2- tetrahedral anions and diammoniumcyclohexane [C6H10(NH3)2]2+ cations, which are connected via N-H…Cl, N-H…O and O-H…N hydrogen bonds. The Hirshfeld surface analysis was conducted to investigate intermolecular interactions and associated 2D fingerprint plots, revealing the relative contribution of these interactions in the crystal structure quantitatively. Theoretical calculations were performed using DFT/B3LYP/LanL2DZ method for studying the molecular structure and vibrational spectra and especially to examine the non-linear optical behavior of the compound. Solid state 13C NMR spectrum shows three signals correspond to three different carbon environments. Thermal analysis discloses a phase transition at the temperature 315 K and the evaporation of water molecule at 327 K. A detailed dielectric study was reported and shows a good agreement with thermal measurements.

  1. Foundations of linear and generalized linear models

    CERN Document Server

    Agresti, Alan

    2015-01-01

    A valuable overview of the most important ideas and results in statistical analysis Written by a highly-experienced author, Foundations of Linear and Generalized Linear Models is a clear and comprehensive guide to the key concepts and results of linear statistical models. The book presents a broad, in-depth overview of the most commonly used statistical models by discussing the theory underlying the models, R software applications, and examples with crafted models to elucidate key ideas and promote practical model building. The book begins by illustrating the fundamentals of linear models,

  2. Hybrid Systems: Computation and Control.

    Science.gov (United States)

    2007-11-02

    elbow) and a pinned first joint (shoul- der) (see Figure 2); it is termed an underactuated system since it is a mechanical system with fewer...Montreal, PQ, Canada, 1998. [10] M. W. Spong. Partial feedback linearization of underactuated mechanical systems . In Proceedings, IROS󈨢, pages 314-321...control mechanism and search for optimal combinations of control variables. Besides the nonlinear and hybrid nature of powertrain systems , hardware

  3. Solving Factored MDPs with Hybrid State and Action Variables

    CERN Document Server

    Guestrin, C; Kveton, B; 10.1613/jair.2085

    2011-01-01

    Efficient representations and solutions for large decision problems with continuous and discrete variables are among the most important challenges faced by the designers of automated decision support systems. In this paper, we describe a novel hybrid factored Markov decision process (MDP) model that allows for a compact representation of these problems, and a new hybrid approximate linear programming (HALP) framework that permits their efficient solutions. The central idea of HALP is to approximate the optimal value function by a linear combination of basis functions and optimize its weights by linear programming. We analyze both theoretical and computational aspects of this approach, and demonstrate its scale-up potential on several hybrid optimization problems.

  4. Rapid, high performance method for the determination of vitamin K(1), menaquinone-4 and vitamin K(1) 2,3-epoxide in human serum and plasma using liquid chromatography-hybrid quadrupole linear ion trap mass spectrometry.

    Science.gov (United States)

    Gentili, Alessandra; Cafolla, Arturo; Gasperi, Tecla; Bellante, Simona; Caretti, Fulvia; Curini, Roberta; Fernández, Virginia Pérez

    2014-04-18

    Unlike the other fat-soluble vitamins, vitamin K circulates in the human bloodstream at very low levels because of a low intake in the diet. Mammals have developed an efficient recycling system, known as vitamin K-epoxide cycle, which involve quinone, hydroquinone and epoxide forms of the vitamin. Phylloquinone (K(1)) is the main homologue, while menaquinone-4 (MK-4) is both a member of the vitamin K(2) family and metabolite of K(1) in extra-hepatic tissues. Notwithstanding the recent advances, many aspects of the complex vitamin K physiology still remain to be investigated. Therefore, there is a critical need to develop more reliable analytical methods for determining the vitamin K and its metabolites in biological fluids and tissues. Nevertheless, relatively low concentrations, unavailability of some authentic standards and occurrence of interfering lipids make this a challenging task. The method proposed in the present paper can directly and accurately estimate K(1), K(1) 2,3-epoxide (K(1)O), and MK-4 in human serum and plasma at concentrations in the ng/L-μg/L range, using labelled internal standards and a quadrupole linear ion trap instrument operated in multiple reaction monitoring (MRM) mode. High sensitivity was achieved by removing signal "endogenous suppressors" and making the composition of the non-aqueous mobile phase suitable to support the positive atmospheric pressure chemical ionization of the analytes. An excellent selectivity resulted from the combination of some factors: the MRM acquisition, the adoption of an identification point system, an extraction optimized to remove most of the lipids and a tandem-C18 column-system necessary to separate isobaric interferences from analytes. The method was validated according to the Food and Drug Administration (FDA) guidelines and its accuracy was assessed by analysing 9 samples from the Vitamin K External Quality Assessment Scheme (KEQAS). Its feasibility in evaluating vitamin K status in human serum was

  5. Feedback linearization of piecewise linear systems

    NARCIS (Netherlands)

    Camlibel, Kanat; Ustoglu, Ilker

    2005-01-01

    One of the classical problems of nonlinear systems and control theory is feedback linearization. Its obvious motivation is that one can utilize linear control theory if the nonlinear system at hand is linearizable by feedback. This problem is well-understood for the smooth nonlinear systems. In the

  6. Hybrid Gear

    Science.gov (United States)

    Handschuh, Robert F. (Inventor); Roberts, Gary D. (Inventor)

    2016-01-01

    A hybrid gear consisting of metallic outer rim with gear teeth and metallic hub in combination with a composite lay up between the shaft interface (hub) and gear tooth rim is described. The composite lay-up lightens the gear member while having similar torque carrying capability and it attenuates the impact loading driven noise/vibration that is typical in gear systems. The gear has the same operational capability with respect to shaft speed, torque, and temperature as an all-metallic gear as used in aerospace gear design.

  7. Hybrid Qualifications

    DEFF Research Database (Denmark)

    has turned out as a major focus of European education and training policies and certainly is a crucial principle underlying the European Qualifications Framework (EQF). In this context, «hybrid qualifications» (HQ) may be seen as an interesting approach to tackle these challenges as they serve «two...... masters», i.e. by producing skills for the labour market and enabling individuals to progress more or less directly to higher education. The specific focus of this book is placed on conditions, structures and processes which help to combine VET with qualifications leading into higher education...

  8. Fault tolerant control design for hybrid systems

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Hao; Jiang, Bin [Nanjing University of Aeronautics and Astronautics, Nanjing (China); Cocquempot, Vincent [Universite des Sciences et Technologies de Lille, Villeneuve d' Ascq (France)

    2010-07-01

    This book intends to provide the readers a good understanding on how to achieve Fault Tolerant Control goal of Hybrid Systems. The book can be used as a reference for the academic research on Fault Tolerant Control and Hybrid Systems or used in Ph.D. study of control theory and engineering. The knowledge background for this monograph would be some undergraduate and graduate courses on Fault Diagnosis and Fault Tolerant Control theory, linear system theory, nonlinear system theory, Hybrid Systems theory and Discrete Event System theory. (orig.)

  9. Advanced propulsion system concept for hybrid vehicles

    Science.gov (United States)

    Bhate, S.; Chen, H.; Dochat, G.

    1980-01-01

    A series hybrid system, utilizing a free piston Stirling engine with a linear alternator, and a parallel hybrid system, incorporating a kinematic Stirling engine, are analyzed for various specified reference missions/vehicles ranging from a small two passenger commuter vehicle to a van. Parametric studies for each configuration, detail tradeoff studies to determine engine, battery and system definition, short term energy storage evaluation, and detail life cycle cost studies were performed. Results indicate that the selection of a parallel Stirling engine/electric, hybrid propulsion system can significantly reduce petroleum consumption by 70 percent over present conventional vehicles.

  10. An overview on hybrid active filters

    Energy Technology Data Exchange (ETDEWEB)

    Libano, Fausto B.; Uceda, Javier [Universidad Politecnica de Madrid (Spain). Division de Ingenieria Electronica; Simonetti, Domingos S.L. [Espirito Santo Univ., Vitoria, ES (Brazil). Dept. de Engenharia Eletrica

    1995-12-31

    This paper summarizes the main hybrid filter methods. A special attention is given to series active filter associations. Nowadays, an hybrid filtering is the preferred choice to improve line performance when feeding high-power non-linear loads. In addition, the use of an independent reference frame leads to a better response comparing to the initial proposition of p-q theory. A comparison of possible filter associations is given, presenting the expected function of each one. The work represents an interesting overview on the state-of-the-art of hybrid filters. (author) 16 refs., 8 figs., 2 tabs.

  11. Genomic Prediction of Barley Hybrid Performance

    Directory of Open Access Journals (Sweden)

    Norman Philipp

    2016-07-01

    Full Text Available Hybrid breeding in barley ( L. offers great opportunities to accelerate the rate of genetic improvement and to boost yield stability. A crucial requirement consists of the efficient selection of superior hybrid combinations. We used comprehensive phenotypic and genomic data from a commercial breeding program with the goal of examining the potential to predict the hybrid performances. The phenotypic data were comprised of replicated grain yield trials for 385 two-way and 408 three-way hybrids evaluated in up to 47 environments. The parental lines were genotyped using a 3k single nucleotide polymorphism (SNP array based on an Illumina Infinium assay. We implemented ridge regression best linear unbiased prediction modeling for additive and dominance effects and evaluated the prediction ability using five-fold cross validations. The prediction ability of hybrid performances based on general combining ability (GCA effects was moderate, amounting to 0.56 and 0.48 for two- and three-way hybrids, respectively. The potential of GCA-based hybrid prediction requires that both parental components have been evaluated in a hybrid background. This is not necessary for genomic prediction for which we also observed moderate cross-validated prediction abilities of 0.51 and 0.58 for two- and three-way hybrids, respectively. This exemplifies the potential of genomic prediction in hybrid barley. Interestingly, prediction ability using the two-way hybrids as training population and the three-way hybrids as test population or vice versa was low, presumably, because of the different genetic makeup of the parental source populations. Consequently, further research is needed to optimize genomic prediction approaches combining different source populations in barley.

  12. Characterization of polyoxyethylene tallow amine surfactants in technical mixtures and glyphosate formulations using ultra-high performance liquid chromatography and triple quadrupole mass spectrometry

    Science.gov (United States)

    Tush, Daniel; Loftin, Keith A.; Meyer, Michael T.

    2013-01-01

    Little is known about the occurrence, fate, and effects of the ancillary additives in pesticide formulations. Polyoxyethylene tallow amine (POEA) is a non-ionic surfactant used in many glyphosate formulations, a widely applied herbicide both in agricultural and urban environments. POEA has not been previously well characterized, but has been shown to be toxic to various aquatic organisms. Characterization of technical mixtures using ultra-high performance liquid chromatography (UHPLC) and mass spectrometry shows POEA is a complex combination of homologs of different aliphatic moieties and ranges of ethoxylate units. Tandem mass spectrometry experiments indicate that POEA homologs generate no product ions readily suitable for quantitative analysis due to poor sensitivity. A comparison of multiple high performance liquid chromatography (HPLC) and UHPLC analytical columns indicates that the stationary phase is more important in column selection than other parameters for the separation of POEA. Analysis of several agricultural and household glyphosate formulations confirms that POEA is a common ingredient but ethoxylate distributions among formulations vary.

  13. Determination of selected pharmaceuticals in tap water and drinking water treatment plant by high-performance liquid chromatography-triple quadrupole mass spectrometer in Beijing, China.

    Science.gov (United States)

    Cai, Mei-Quan; Wang, Rong; Feng, Li; Zhang, Li-Qiu

    2015-02-01

    A simultaneous determination method of 14 multi-class pharmaceuticals using solid-phase extraction (SPE) followed by high-performance liquid chromatography-tandem mass spectrometer (HPLC-MS/MS) was established to measure the occurrence and distribution of these pharmaceuticals in tap water and a drinking water treatment plant (DWTP) in Beijing, China. Target compounds included seven anti-inflammatory drugs, two antibacterial drugs, two lipid regulation drugs, one antiepileptic drug, and one hormone. Limits of detection (LODs) and limits of quantitation (LOQs) ranged from 0.01 to 1.80 ng/L and 0.05 to 3.00 ng/L, respectively. Intraday and inter-day precisions, recoveries of different matrices, and matrix effects were also investigated. Of the 14 pharmaceutical compounds selected, nine were identified in tap water of Beijing downtown with the concentration up to 38.24 ng/L (carbamazepine), and the concentration levels of detected pharmaceuticals in tap water (water and finished water at the concentration ranged from 0.10 to 16.23 and 0.13 to 17.17 ng/L, respectively. Five compounds were detected most frequently in DWTP, namely antipyrine, carbamazepine, isopropylantipyrine, aminopyrine, and bezafibrate. Ibuprofen was found to be the highest concentration pharmaceutical during DWTP, up to 53.30 ng/L. DWTP shows a positive effect on the removal of most pharmaceuticals with 81.2-99.5 % removal efficiencies, followed by carbamazepine with 55.4 % removal efficiency, but it has no effect for removing ibuprofen and bezafibrate.

  14. Application of gas chromatography–(triple quadrupole) massspectrometry with atmospheric pressure chemical ionization for thedetermination of multiclass pesticides in fruits and vegetables

    NARCIS (Netherlands)

    Cherta, L.; Portoles, T.; Beltran, J.; Pitarch, E.; Mol, J.G.J.; Hernandez, F.

    2013-01-01

    A multi-residue method for the determination of 142 pesticide residues in fruits and vegetables has been developed using a new atmospheric pressure chemical ionization (APCI) source for coupling gas chromatography (GC) to tandem mass spectrometry (MS). Selected reaction monitoring (SRM) mode has bee

  15. Multiresidue analysis of plant growth regulators in grapes by triple quadrupole and quadrupole-time of flight-based liquid chromatography/mass spectrometry.

    Science.gov (United States)

    Oulkar, Dasharath P; Banerjee, Kaushik; Kulkarni, Sunil

    2011-01-01

    A selective and sensitive LC-MS/MS method is presented for simultaneous determination of 12 plant growth regulators, viz., indol-3-acetic acid, indol-3-butyric acid, kinetin, zeatin, 6-benzyl aminopurine, gibberellic acid, abscisic acid, chlormequat chloride, forchlorfenuron, paclobutrazole, daminozide, and 2,4-dichlorophenoxy acetic acid, in bud sprouts and grape berries. The sample preparation method involved extraction of homogenized sample (5 g) with 40 mL methanol (80%), and final determination was by LC-MS/MS in the multiple reaction monitoring (MRM) mode with time segmentation for quantification supported by complementary analysis by quadrupole-time of flight (Q-TOF) MS with targeted high-resolution MS/MS scanning for confirmatory identification based on accurate mass measurements. The recovery of the test compounds ranged within 90-107% with precision RSD less than 5% (n = 6). The method could be successfully applied in analyzing incurred residue samples, and the strength of accurate mass analysis could be utilized in identifying the compounds in cases where the qualifier MRM ions were absent or at an S/N less than 3:1 due to low concentrations.

  16. Comparison of veterinary drug residue results in animal tissues by ultrahigh-performance liquid chromatography coupled to triple quadrupole ... use of a commercial lipid removal product

    Science.gov (United States)

    Veterinary drug residues in animal-derived foods must be monitored to ensure food safety, verify proper veterinary practices, enforce legal limits in domestic and imported foods, and other purposes. A common goal in drug residue analysis in foods is to achieve acceptable monitoring results for as m...

  17. Adduct ion-targeted qualitative and quantitative analysis of polyoxypregnanes by ultra-high pressure liquid chromatography coupled with triple quadrupole mass spectrometry.

    Science.gov (United States)

    Wu, Xu; Zhu, Lin; Ma, Jiang; Ye, Yang; Lin, Ge

    2017-10-25

    Polyoxypregnane and its glycosides (POPs) are frequently present in plants of Asclepiadaceae family, and have a variety of biological activities. There is a great need to comprehensively profile these phytochemicals and to quantify them for monitoring their contents in the herbs and the biological samples. However, POPs undergo extensive adduct ion formation in ESI-MS, which has posed a challenge for qualitative and quantitative analysis of POPs. In the present study, we took the advantage of such extensive adduct ion formation to investigate the suitability of adduct ion-targeted analysis of POPs. For the qualitative analysis, we firstly demonstrated that the sodium and ammonium adduct ion-targeted product ion scans (PIS) provided adequate MS/MS fragmentations for structural characterization of POPs. Aided with precursor ion (PI) scans, which showed high selectivity and sensitivity and improved peak assignment confidence in conjunction with full scan (FS), the informative adduct ion-targeted PIS enabled rapid POPs profiling. For the quantification, we used formic acid rather than ammonium acetate as an additive in the mobile phase to avoid simultaneous formation of sodium and ammonium adduct ions, and greatly improved reproducibility of MS response of POPs. By monitoring the solely formed sodium adduct ions [M+Na](+), a method for simultaneous quantification of 25 POPs in the dynamic multiple reaction monitoring mode was then developed and validated. Finally, the aforementioned methods were applied to qualitative and quantitative analysis of POPs in the extract of a traditional Chinses medicinal herb, Marsdenia tenacissima (Roxb.) Wight et Arn., and in the plasma obtained from the rats treated with this herb. The results demonstrated that adduct ion formation could be optimized for the qualitative and quantitative analysis of POPs, and our developed PI/FS-PIS scanning and sole [M+Na](+) ion monitoring significantly improved the analysis of POPs in both herbal and biological samples. This study also provides implications for the analysis of other compounds which undergo extensive adduct ion formation in ESI-MS. Copyright © 2017 Elsevier B.V. All rights reserved.

  18. Determination of hydrazine in drinking water: Development and multivariate optimization of a rapid and simple solid phase microextraction-gas chromatography-triple quadrupole mass spectrometry protocol.

    Science.gov (United States)

    Gionfriddo, Emanuela; Naccarato, Attilio; Sindona, Giovanni; Tagarelli, Antonio

    2014-07-04

    In this work, the capabilities of solid phase microextraction were exploited in a fully optimized SPME-GC-QqQ-MS analytical approach for hydrazine assay. A rapid and easy method was obtained by a simple derivatization reaction with propyl chloroformate and pyridine carried out directly in water samples, followed by automated SPME analysis in the same vial without further sample handling. The affinity of the different derivatized compounds obtained towards five commercially available SPME coatings was evaluated, in order to achieve the best extraction efficiency. GC analyses were carried out using a GC-QqQ-MS instrument in selected reaction monitoring (SRM) acquisition mode which has allowed the achievement of high specificity by selecting appropriate precursor-product ion couples improving the capability in analyte identification. The multivariate approach of experimental design was crucial in order to optimize derivatization reaction, SPME process and tandem mass spectrometry parameters. Accuracy of the proposed protocol, tested at 60, 200 and 800 ng L(-1), provided satisfactory values (114.2%, 83.6% and 98.6%, respectively), whereas precision (RSD%) at the same concentration levels were of 10.9%, 7.9% and 7.7% respectively. Limit of detection and quantification of 4.4 and 8.3 ng L(-1) were obtained. The reliable application of the proposed protocol to real drinking water samples confirmed its capability to be used as analytical tool for routine analyses.

  19. GC determination of N-nitrosamines by supersonic molecular beam MS equipped with triple quadrupole analyzer, GC/SMB/QQQ/MS.

    Science.gov (United States)

    Anna, Voloshenko; Rimma, Shelkov; Lev, Ovadia; Jenny, Gun

    2011-01-31

    The determination of 14 N-nitrosamines by a supersonic molecular beam electron ionization mass spectrometer equipped with triple quadruple analyzer, GC/SMB/EI/QQQ/MS is presented. The supersonic molecular beam electron ionization ion source allows the elucidation of the molecular ion of 13 out of the 14 examined nitrosamines (except for diphenylnitrosamine which was degraded before the analysis). It was possible to use the molecular ions of all the nitrosamines as the parent ions for multiple reactions monitoring mode, which in turn allows significant increase of specificity and lowering of the method limit of detection of the higher molecular weight nitrosamines. The instrumental LOD for different N-nitrosamines was 1-5 pg injection(-1). The proposed method was exemplified by analysis of N-nitrosamines and N-nitrosatables in rubber teats according to the British Standard BS EN 12868:1999. Copyright © 2010. Published by Elsevier B.V.

  20. Characterization of polyoxyethylene tallow amine surfactants in technical mixtures and glyphosate formulations using ultra-high performance liquid chromatography and triple quadrupole mass spectrometry.

    Science.gov (United States)

    Tush, Daniel; Loftin, Keith A; Meyer, Michael T

    2013-12-06

    Little is known about the occurrence, fate, and effects of the ancillary additives in pesticide formulations. Polyoxyethylene tallow amine (POEA) is a non-ionic surfactant used in many glyphosate formulations, a widely applied herbicide both in agricultural and urban environments. POEA has not been previously well characterized, but has been shown to be toxic to various aquatic organisms. Characterization of technical mixtures using ultra-high performance liquid chromatography (UHPLC) and mass spectrometry shows POEA is a complex combination of homologs of different aliphatic moieties and ranges of ethoxylate units. Tandem mass spectrometry experiments indicate that POEA homologs generate no product ions readily suitable for quantitative analysis due to poor sensitivity. A comparison of multiple high performance liquid chromatography (HPLC) and UHPLC analytical columns indicates that the stationary phase is more important in column selection than other parameters for the separation of POEA. Analysis of several agricultural and household glyphosate formulations confirms that POEA is a common ingredient but ethoxylate distributions among formulations vary.

  1. Rapid quantitation of avenanthramides in oat-containing products by high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-TQMS).

    Science.gov (United States)

    Xie, Zhuohong; Mui, Tracy; Sintara, Marsha; Ou, Boxin; Johnson, Jodee; Chu, YiFang; O'shea, Marianne; Kasturi, Prabhakar; Chen, Yumin

    2017-06-01

    Avenanthramides (AVNs) are a family of nitrogen-containing phenolic compounds produced in oat; AVN 2c, 2p, and 2f are the three major members. An LC-MS/MS method was developed, with the limit of detection (LOD) and the limit of quantitation (LOQ) being, respectively, 0.29ng/mL and 1.96ng/mL for AVN 2c, 0.24ng/mL and 0.60ng/mL for AVE 2p, and 0.42ng/mL and 2.2ng/mL for AVN 2f. The method was validated in oat-containing hot cereal and snack bar samples. The recovery of AVN 2c, 2p, and 2f from these two oat products was 95-113%, and the relative standard deviations ranged from 5% to 9%. This method was used to evaluate oat products and raw oat samples. The effects of location and variety on AVN composition were investigated. The method presented here provides a novel and rapid tool to quantitate the abundance of AVN 2c, 2p, and 2f in oat-containing products.

  2. Identification of in vitro metabolites of Indinavir by "intelligent automated LC-MS/MS" (INTAMS) utilizing triple quadrupole tandem mass spectrometry.

    Science.gov (United States)

    Yu, X; Cui, D; Davis, M R

    1999-02-01

    In an effort to improve the efficiency of the TSQ 7000 LC-MS/MS system for identification of drug metabolites in biological matrices in support of drug discovery programs, a combination of instrument control language procedures for the Finnigan MAT TSQ 7000 mass spectrometer, referred to as INTAMS, were composed. INTAMS was designed to conduct unattended, automatic liquid chromatography/mass spectrometry (LC-MS) and LC-MS/MS analyses of drugs and metabolites in commonly encountered in vitro biological matrices. A novel peak detection algorithm was developed to automatically detect and record the pseudomolecular ions and retention times of chromatographic components, even if not fully resolved. This algorithm was used in combination with an automated technique for predicting the molecular weights of metabolites based on incremental changes of the molecular weight of the parent drug resulting from well-known biotransformation processes. When applied to a sample of an incubation mixture of the HIV protease inhibitor Indinavir with a rat liver S9 preparation, the results obtained by the automatic metabolite detection procedures for LC-MS and LC-MS/MS analyses in real time were the same as those which were determined manually, by a knowledgeable operator.

  3. Optimised extraction of heterocyclic aromatic amines from blood using hollow fibre membrane liquid-phase microextraction and triple quadrupole mass spectrometry.

    Science.gov (United States)

    Cooper, Kevin M; Jankhaikhot, Natcha; Cuskelly, Geraldine

    2014-09-05

    Heterocyclic aromatic amines (HCA) are carcinogenic mutagens formed during cooking of proteinaceous foods, particularly meat. To assist in the ongoing search for biomarkers of HCA exposure in blood, a method is described for the extraction from human plasma of the most abundant HCAs: 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine (PhIP), 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) and 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4,8-DiMeIQx) (and its isomer 7,8-DiMeIQx), using hollow fibre membrane liquid-phase microextraction. This technique employs 2.5cm lengths of porous polypropylene fibres impregnated with organic solvent to facilitate simultaneous extraction from an alkaline aqueous sample into a low volume acidic acceptor phase. This low cost protocol is extensively optimised for fibre length, extraction time, sample pH and volume. Detection is by UPLC-MS/MS using positive mode electrospray ionisation with a 3.4min runtime, with optimum peak shape, sensitivity and baseline separation being achieved at pH 9.5. To our knowledge this is the first description of HCA chromatography under alkaline conditions. Application of fixed ion ratio tolerances for confirmation of analyte identity is discussed. Assay precision is between 4.5 and 8.8% while lower limits of detection between 2 and 5pg/mL are below the concentrations postulated for acid-labile HCA-protein adducts in blood.

  4. Highly sensitive and rapid profiling method for carotenoids and their epoxidized products using supercritical fluid chromatography coupled with electrospray ionization-triple quadrupole mass spectrometry.

    Science.gov (United States)

    Matsubara, Atsuki; Uchikata, Takato; Shinohara, Masakazu; Nishiumi, Shin; Yoshida, Masaru; Fukusaki, Eiichiro; Bamba, Takeshi

    2012-06-01

    Epoxy carotenoids, which are products of carotenoid oxidation, are potential oxidative stress markers. However, it is difficult to profile epoxy carotenoids owing to their small amount and difficulty in their separation from hydroxy carotenoids. In this study, a high-performance analytical system based on supercritical fluid chromatography (SFC) coupled with tandem mass spectrometry (MS/MS) was developed for the simultaneous analysis of carotenoids and epoxy carotenoids. SFC is an effective separation technique for hydrophobic compounds, by which major carotenoids in human serum and their epoxidation products can be analyzed within 20 min. The use of MS/MS increased the sensitivity; the detection limit for each carotenoid was of the sub-fmol order. When the constructed method was applied to biological samples such as human serum and low-density lipoprotein (LDL), the precise detection of the target carotenoids was disturbed by several isomers. However, highly selective detection of epoxy carotenoids was performed by targeting product ions that were generated with a structure-specific neutral loss of 80Da. Furthermore, the sample volume needed for the analysis was only 0.1ml for the serum, indicating the efficiency of this system in performing small-scale analyses. Using the analytical system developed in this study, highly sensitive and selective analysis of epoxy carotenoids could be performed in a short time. These features show the usefulness of this system in application to screening analysis of carotenoid profiles that are easily modified by oxidative stress.

  5. Determination of low-level ink photoinitiator residues in packaged milk by solid-phase extraction and LC-ESI/MS/MS using triple-quadrupole mass analyzer.

    Science.gov (United States)

    Shen, Dong-xu; Lian, Hong-zhen; Ding, Tao; Xu, Jin-zhong; Shen, Chong-yu

    2009-12-01

    A confirmatory and quantitative method based on liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI/MS/MS) has been developed for simultaneous determination of seven photoinitiator residues: benzophenone, (1-hydroxycyclohexyl)phenylketone (Irgacure 184), isopropylthioxanthone (ITX), 2-ethylhexyl-(4-dimethylamino)benzoate (EHA or EHDAB), 2-methyl-1-[4-(methylthio)phenyl]-2-(4-morpholinyl)-1-propanone (Irgacure 907), (2,4,6-trimethylbenzoyl)diphenylphosphine oxide (TPO) and 2-benzyl-2-(dimethylamino)-1-(4-morpholinophenyl)-1-butanone (Irgacure 369) in packaged milk and related packaging materials. Residues of photoinitiators were extracted from milk using acetonitrile, and further enriched and purified on HLB solid-phase extraction cartridges prior to being analyzed by LC-ESI/MS/MS with selected reaction monitoring mode, while photoinitiators in packaging materials were extracted using the same solvent. Satisfactory recovery (from 80 to 111%), intra- and inter-day precision (below 12%), and low limits of quantification (from 0.1 to 5.0 microg kg(-1)) were evaluated from spiked samples at three concentration levels (5.0, 10.0 and 25.0 microg kg(-1) for Irgacure 184 and 2.5, 5.0 and 25.0 microg kg(-1) for others). These excellent validation data suggested the possibility of using the LC-ESI/MS/MS method for simultaneous determination of low-level photoinitiator residues migrating from printed food-packaging materials into milk. The method has been successfully applied to the analysis of real samples of different fat contents ranging from 8 to 30 g L(-1). The photoinitiator residues were revealed to be higher in milk with higher fat content and the most important contaminations were benzophenone and ITX in concentration ranges of 2.84-18.35 and 0.83-8.87 microg kg(-1), respectively.

  6. Determination of type A and type B trichothecenes in paprika and chili pepper using LC-triple quadrupole-MS and GC-ECD.

    Science.gov (United States)

    Valle-Algarra, Francisco M; Mateo, Eva M; Mateo, Rufino; Gimeno-Adelantado, Jose V; Jiménez, Misericordia

    2011-05-30

    There is a need to develop sensitive and accurate analytical methods for determining deoxynivalenol (DON), HT-2 toxin and T-2 toxin in paprika to properly assess the relevant risk of human exposure. An optimized analytical method for determination of HT-2 toxin and T-2 toxin using capillary gas chromatography with electron capture detection and another method for determination of DON by liquid chromatography-mass spectrometry in paprika was developed. The method for determination of HT-2 toxin and T-2 toxin that gave the best recoveries involved extraction of the sample with acetonitrile-water (84:16, v/v), clean-up by solid-phase extraction on a cartridge made of different sorbent materials followed by a further clean-up in immunoaffinity column that was specific for the two toxins. The solvent was changed and the eluate was derivatized with pentafluoropropionic anhydride and injected into the GC system. The limits of detection (LOD) for T-2 and HT-2 toxins were 7 and 3 μg/kg, respectively, and the recovery rates for paprika spiked with 1000 μg toxin/kg were 71.1% and 80.1% for HT-2 and T-2 toxins, respectively. For DON determination, the optimized method consisted of extraction with acetonitrile-water (84:16, v/v) solution followed by a solid-phase extraction clean-up process in a cartridge made of different sorbent compounds. After solvent evaporation in N(2) stream, the residue was dissolved and DON was separated and determined by LC-MS/MS. The LOD for this method was 14 μg DON/kg paprika sample and the DON recovery rate was 86.8%.

  7. Simultaneous determination of taurine, glucuronolactone and glucuronic acid in energy drinks by ultra high performance liquid chromatography-tandem mass spectrometry (triple quadrupole).

    Science.gov (United States)

    Ricciutelli, Massimo; Caprioli, Giovanni; Cortese, Manuela; Lombardozzi, Antonietta; Strano, Morela; Vittori, Sauro; Sagratini, Gianni

    2014-10-17

    In this work, we present for the first time a rapid and robust UHPLC-MS/MS method for analyzing taurine, GlcLA and GlcA in energy drinks simultaneously and without derivatization. The separation of three analytes was achieved using a Kinetex Hilic analytical column (100 mm × 4.6 mm i.d.) and a mobile phase formed by water (A) and acetonitrile (B) both with formic acid 0.1% at a flow rate of 0.8 ml min(-1) with isocratic elution in 3.5 min. Calibration curves were calculated using the method of standard addition in a concentration range from 2 to 6 mg/100 ml for taurine (R(2)>0.987), from 0.4 to 1.2 mg/100 ml for GlcLa (R(2)>0.997), and from 0.2 to 0.6 mg/100 ml for GlcA acid (R(2)>0.998). The validated method was applied to the analysis of nine commercial energy drinks. The level of taurine found ranged from 0.01 to 0.45 g/100 ml, and it matched with that reported in the labels of the analyzed energy drink samples.

  8. Semi-automated tandem mass spectrometric (MS/MS) triple quadrupole operating parameter optimization for high-throughput MS/MS detection workflows.

    Science.gov (United States)

    Geddes, Kristin; Adamson, Gary; Dube, Neal; Crathern, Susan; King, Richard C

    2009-05-01

    This paper describes an automated workflow for the determination of selected reaction monitoring (SRM) transitions and optimum mass spectrometric (MS) instrument parameters. The approach uses a Nanomate from Advion Biosciences for automated infusion of small amounts of sample in combination with Automaton optimization software from Sciex. The results are stored in the Analyst software Compound Database for automated acquisition method building. Comparisons are presented between the more traditional optimization methods of manual flow injection optimization, Autotune infusion optimization, Automaton flow injection optimization and the Nanomate-Automaton optimization approach. Data is also presented to show that acquisition methods developed on the Sciex model API3000 instrument can be effectively transferred to the Sceix API4000 and API5000 model instruments. Copyright (c) 2009 John Wiley & Sons, Ltd.

  9. Determination of estrogenic compounds in milk and yogurt samples by hollow-fibre liquid-phase microextraction-gas chromatography-triple quadrupole mass spectrometry.

    Science.gov (United States)

    D'Orazio, Giovanni; Hernández-Borges, Javier; Herrera-Herrera, Antonio Vicente; Fanali, Salvatore; Rodríguez-Delgado, Miguel Ángel

    2016-10-01

    An environmentally friendly method based on hollow-fibre liquid-phase microextraction (HF-LPME) was developed for the extraction of selected estrogenic compounds (i.e. four natural sexual hormones: estrone, 17β-estradiol, 17α-estradiol and estriol; two exoestrogens: 17α-ethynylestradiol and 2-methoxyestradiol; two synthetic stilbenes: dienestrol and hexestrol; and five resorcylic acid lactones: zearalenone, α-zearalanol, β-zearalanol, α-zearalenol and β-zearalenol), from whole cow and semi-skimmed goat milk and whole natural yogurt. After the optimization of the sample preparation procedure, spiked extracts were derivatized to their trimethylsilyl products using N,O-bis(trimethylsilyl)trifluoroacetamide reagent and then analyzed by gas chromatography-tandem mass spectrometry (GC-MS/MS). Once optimum extraction conditions were established (protein precipitation with acetonitrile, extraction and the back-extraction in acetonitrile following the HF-LPME procedure), the method was validated and the calibration range, precision and accuracy were studied. The RSD values for the intra- and inter-day precision of the peak areas were in the range 0.65-9.69 and 1.00-11.47 %, respectively. The determination coefficients were higher than 0.991 for method calibration curves while LOD and LOQ values were between 0.06-2.55 and 0.16-6.11 μg/L for whole cow milk, 0.04-1.70 and 0.11-4.86 μg/L for semi-skimmed goat milk and 0.07-3.73 and 0.23-9.81 μg/L for natural yogurt, respectively. Finally, the accuracy and precision of the method were evaluated, obtaining a value in the range 84 81-119 % and RSD values lower than 20 % in all cases.

  10. Quantitative Analysis of Mixed Halogen Dioxins and Furans in Fire Debris Utilizing Atmospheric Pressure Ionization Gas Chromatography-Triple Quadrupole Mass Spectrometry.

    Science.gov (United States)

    Organtini, Kari L; Myers, Anne L; Jobst, Karl J; Reiner, Eric J; Ross, Brian; Ladak, Adam; Mullin, Lauren; Stevens, Douglas; Dorman, Frank L

    2015-10-20

    Residential and commercial fires generate a complex mixture of volatile, semivolatile, and nonvolatile compounds. This study focused on the semi/nonvolatile components of fire debris to better understand firefighter exposure risks. Using the enhanced sensitivity of gas chromatography coupled to atmospheric pressure ionization-tandem mass spectrometry (APGC-MS/MS), complex fire debris samples collected from simulation fires were analyzed for the presence of potentially toxic polyhalogenated dibenzo-p-dioxins and dibenzofurans (PXDD/Fs and PBDD/Fs). Extensive method development was performed to create multiple reaction monitoring (MRM) methods for a wide range of PXDD/Fs from dihalogenated through hexa-halogenated homologue groups. Higher halogenated compounds were not observed due to difficulty eluting them off the long column used for analysis. This methodology was able to identify both polyhalogenated (mixed bromo-/chloro- and polybromo-) dibenzo-p-dioxins and dibenzofurans in the simulated burn study samples collected, with the dibenzofuran species being the dominant compounds in the samples. Levels of these compounds were quantified as total homologue groups due to the limitations of commercial congener availability. Concentration ranges in household simulation debris were observed at 0.01-5.32 ppb (PXDFs) and 0.18-82.11 ppb (PBDFs). Concentration ranges in electronics simulation debris were observed at 0.10-175.26 ppb (PXDFs) and 0.33-9254.41 ppb (PBDFs). Samples taken from the particulate matter coating the firefighters' helmets contained some of the highest levels of dibenzofurans, ranging from 4.10 ppb to 2.35 ppm. The data suggest that firefighters and first responders at fire scenes are exposed to a complex mixture of potentially hundreds to thousands of different polyhalogenated dibenzo-p-dioxins and dibenzofurans that could negatively impact their health.

  11. Structure of coal: new approaches to characterizing organonitrogen and organosulfur functionalities in coal and coal liquids. Final report. [Finnigan triple quadrupole mass spectrometers

    Energy Technology Data Exchange (ETDEWEB)

    Cooks, R.G.

    1983-01-01

    This report describes the application of tandem mass spectrometry (MS/MS) to the analysis of coal-related materials. A Finnigan Triple State Quadrupole mass spectrometer was used for most of the results obtained in this study. Both collision energy (0 to 30 eV) and collision gas pressure (0 to 2.5 mtorr, typically argon) have significant effects on the spectra. Increasing the collision energy or collision pressure results in an increased fragmentation of the selected ion. The analytical utility of different chemical ionization (CI) reagent gases is shown. The MS/MS spectra of a selected ion obtained by isobutane and ammonia CI are identical, which paves the way for development of MS/MS libraries. A library is being developed especially for the analysis of coal-related materials. Three principal MS/MS scan modes (daughter, parent and neutral loss) are utilized in the analysis of coal-related materials. Parent and neutral loss scans characterize the complex mixture for particular chemical moieties (functional groups, structure type), while daughter scans are used for identification of specific components. SRC II was the principal sample studied by CI. Laser desorption methodology for coal analysis was developed. Other fuel-related materials were examined to generalize the analytical methodology being developed for the coal-related materials, including shale oil and diesel exhaust particulates. 35 references, 50 figures, 3 tables.

  12. Hybrid piezoelectric energy harvesting transducer system

    Science.gov (United States)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  13. Hybrid sol-gel optical materials

    Science.gov (United States)

    Zeigler, John M.

    1992-01-01

    Hybrid sol-gel materials comprise silicate sols cross-linked with linear polysilane, polygermane, or poly(silane-germane). The sol-gel materials are useful as optical identifiers in tagging and verification applications and, in a different aspect, as stable, visible light transparent non-linear optical materials. Methyl or phenyl silicones, polyaryl sulfides, polyaryl ethers, and rubbery polysilanes may be used in addition to the linear polysilane. The linear polymers cross-link with the sol to form a matrix having high optical transparency, resistance to thermooxidative aging, adherence to a variety of substrates, brittleness, and a resistance to cracking during thermal cycling.

  14. Intuitionistic hybrid logic

    DEFF Research Database (Denmark)

    Braüner, Torben

    2011-01-01

    Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area.......Intuitionistic hybrid logic is hybrid modal logic over an intuitionistic logic basis instead of a classical logical basis. In this short paper we introduce intuitionistic hybrid logic and we give a survey of work in the area....

  15. Continuity Controlled Hybrid Automata

    OpenAIRE

    Bergstra, J. A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of hybrid automata as timed transition systems. We also relate the synchronized product operator on hybrid automata to the parallel composition operator of the process algebra. It turns out that the f...

  16. Hybridized tetraquarks

    Directory of Open Access Journals (Sweden)

    A. Esposito

    2016-07-01

    Full Text Available We propose a new interpretation of the neutral and charged X,Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules but rather a manifestation of the interplay between the two. While meson molecules need a negative or zero binding energy, its counterpart for h-tetraquarks is required to be positive. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs0π± channel by the D0 Collaboration and the negative result presented subsequently by the LHCb Collaboration are understood in this scheme, together with a considerable portion of available data on X,Z particles. Considerations on a state with the same quantum numbers as the X(5568 are also made.

  17. Hybridized Tetraquarks

    CERN Document Server

    Esposito, A.; Polosa, A.D.

    2016-01-01

    We propose a new interpretation of the neutral and charged X, Z exotic hadron resonances. Hybridized-tetraquarks are neither purely compact tetraquark states nor bound or loosely bound molecules. The latter would require a negative or zero binding energy whose counterpart in h-tetraquarks is a positive quantity. The formation mechanism of this new class of hadrons is inspired by that of Feshbach metastable states in atomic physics. The recent claim of an exotic resonance in the Bs pi+- channel by the D0 collaboration and the negative result presented subsequently by the LHCb collaboration are understood in this scheme, together with a considerable portion of available data on X, Z particles. Considerations on a state with the same quantum numbers as the X(5568) are also made.

  18. Discodermolide/Dictyostatin hybrids: synthesis and biological evaluation.

    Science.gov (United States)

    Shin, Youseung; Choy, Nakyen; Turner, Tiffany R; Balachandran, Raghavan; Madiraju, Charitha; Day, Billy W; Curran, Dennis P

    2002-12-12

    [structure: see text] Two hybrid analogues of discodermolide and dictyostatin (3, 26) have been designed and synthesized. These are the first macrocyclic analogues of discodermolide and biological activities were evaluated and compared with linear discodermolide analogues.

  19. A linear programming manual

    Science.gov (United States)

    Tuey, R. C.

    1972-01-01

    Computer solutions of linear programming problems are outlined. Information covers vector spaces, convex sets, and matrix algebra elements for solving simultaneous linear equations. Dual problems, reduced cost analysis, ranges, and error analysis are illustrated.

  20. Classifying Linear Canonical Relations

    OpenAIRE

    Lorand, Jonathan

    2015-01-01

    In this Master's thesis, we consider the problem of classifying, up to conjugation by linear symplectomorphisms, linear canonical relations (lagrangian correspondences) from a finite-dimensional symplectic vector space to itself. We give an elementary introduction to the theory of linear canonical relations and present partial results toward the classification problem. This exposition should be accessible to undergraduate students with a basic familiarity with linear algebra.

  1. Linear shaped charge

    Energy Technology Data Exchange (ETDEWEB)

    Peterson, David; Stofleth, Jerome H.; Saul, Venner W.

    2017-07-11

    Linear shaped charges are described herein. In a general embodiment, the linear shaped charge has an explosive with an elongated arrowhead-shaped profile. The linear shaped charge also has and an elongated v-shaped liner that is inset into a recess of the explosive. Another linear shaped charge includes an explosive that is shaped as a star-shaped prism. Liners are inset into crevices of the explosive, where the explosive acts as a tamper.

  2. On Regular Linear Relations

    Institute of Scientific and Technical Information of China (English)

    T. (A)LVAREZ

    2012-01-01

    For a closed linear relation in a Banach space the concept of regularity is introduced and studied.It is shown that many of the results of Mbekhta and other authors for operators remain valid in the context of multivalued linear operators.We also extend the punctured neighbourhood theorem for operators to linear relations and as an application we obtain a characterization of semiFredholm linear relations which are regular.

  3. Linear-Algebra Programs

    Science.gov (United States)

    Lawson, C. L.; Krogh, F. T.; Gold, S. S.; Kincaid, D. R.; Sullivan, J.; Williams, E.; Hanson, R. J.; Haskell, K.; Dongarra, J.; Moler, C. B.

    1982-01-01

    The Basic Linear Algebra Subprograms (BLAS) library is a collection of 38 FORTRAN-callable routines for performing basic operations of numerical linear algebra. BLAS library is portable and efficient source of basic operations for designers of programs involving linear algebriac computations. BLAS library is supplied in portable FORTRAN and Assembler code versions for IBM 370, UNIVAC 1100 and CDC 6000 series computers.

  4. Linear-Algebra Programs

    Science.gov (United States)

    Lawson, C. L.; Krogh, F. T.; Gold, S. S.; Kincaid, D. R.; Sullivan, J.; Williams, E.; Hanson, R. J.; Haskell, K.; Dongarra, J.; Moler, C. B.

    1982-01-01

    The Basic Linear Algebra Subprograms (BLAS) library is a collection of 38 FORTRAN-callable routines for performing basic operations of numerical linear algebra. BLAS library is portable and efficient source of basic operations for designers of programs involving linear algebriac computations. BLAS library is supplied in portable FORTRAN and Assembler code versions for IBM 370, UNIVAC 1100 and CDC 6000 series computers.

  5. Analysis of chromosome aberration data by hybrid-scale models

    Energy Technology Data Exchange (ETDEWEB)

    Indrawati, Iwiq [Research and Development on Radiation and Nuclear Biomedical Center, National Nuclear Energy Agency (Indonesia); Kumazawa, Shigeru [Nuclear Technology and Education Center, Japan Atomic Energy Research Institute, Honkomagome, Tokyo (Japan)

    2000-02-01

    This paper presents a new methodology for analyzing data of chromosome aberrations, which is useful to understand the characteristics of dose-response relationships and to construct the calibration curves for the biological dosimetry. The hybrid scale of linear and logarithmic scales brings a particular plotting paper, where the normal section paper, two types of semi-log papers and the log-log paper are continuously connected. The hybrid-hybrid plotting paper may contain nine kinds of linear relationships, and these are conveniently called hybrid scale models. One can systematically select the best-fit model among the nine models by among the conditions for a straight line of data points. A biological interpretation is possible with some hybrid-scale models. In this report, the hybrid scale models were applied to separately reported data on chromosome aberrations in human lymphocytes as well as on chromosome breaks in Tradescantia. The results proved that the proposed models fit the data better than the linear-quadratic model, despite the demerit of the increased number of model parameters. We showed that the hybrid-hybrid model (both variables of dose and response using the hybrid scale) provides the best-fit straight lines to be used as the reliable and readable calibration curves of chromosome aberrations. (author)

  6. EXPONENTIAL ESTIMATES FOR STOCHASTIC DELAY HYBRID SYSTEMS WITH MARKOVIAN SWITCHING

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper deals with the problem of norm bounds for the solutions of stochastic hybrid systems with Markovian switching and time delay. Based on Lyapunov-Krasovskii theory for functional differential equations and the linear matrix inequality (LMI) approach, mean square exponential estimates for the solutions of this class of linear stochastic hybrid systems are derived. Finally, An example is illustrated to show the applicability and effectiveness of our method.

  7. Continuity Controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2004-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  8. Continuity controlled Hybrid Automata

    NARCIS (Netherlands)

    Bergstra, J.A.; Middelburg, C.A.

    2008-01-01

    We investigate the connections between the process algebra for hybrid systems of Bergstra and Middelburg and the formalism of hybrid automata of Henzinger et al. We give interpretations of hybrid automata in the process algebra for hybrid systems and compare them with the standard interpretation of

  9. Advanced linear algebra

    CERN Document Server

    Cooperstein, Bruce

    2010-01-01

    Vector SpacesFieldsThe Space FnVector Spaces over an Arbitrary Field Subspaces of Vector SpacesSpan and IndependenceBases and Finite Dimensional Vector SpacesBases and Infinite Dimensional Vector SpacesCoordinate VectorsLinear TransformationsIntroduction to Linear TransformationsThe Range and Kernel of a Linear TransformationThe Correspondence and Isomorphism TheoremsMatrix of a Linear TransformationThe Algebra of L(V, W) and Mmn(F)Invertible Transformations and MatricesPolynomialsThe Algebra of PolynomialsRoots of PolynomialsTheory of a Single Linear OperatorInvariant Subspaces of an Operator

  10. A multiconfigurational hybrid density-functional theory

    DEFF Research Database (Denmark)

    Sharkas, Kamal; Savin, Andreas; Jensen, Hans Jørgen Aagaard

    2012-01-01

    We propose a multiconfigurational hybrid density-functional theory which rigorously combines a multiconfiguration self-consistent-field calculation with a density-functional approximation based on a linear decomposition of the electron-electron interaction. This gives a straightforward extension ...

  11. A multiconfigurational hybrid density-functional theory

    DEFF Research Database (Denmark)

    Sharkas, Kamal; Savin, Andreas; Jensen, Hans Jørgen Aagaard

    2012-01-01

    We propose a multiconfigurational hybrid density-functional theory which rigorously combines a multiconfiguration self-consistent-field calculation with a density-functional approximation based on a linear decomposition of the electron-electron interaction. This gives a straightforward extension ...

  12. Recent Advances in Fluorescence in situ Hybridization

    OpenAIRE

    吉田, 廸弘; Michihiro C., Yoshida; 北海道大学理学部附属動物染色体研究施設; Chromosome Research Unit, Faculty of Science, Hokkaido University

    1992-01-01

    Fluorescence in situ hybridization (FISH) procedures that directly couple molecular and cytological information allow precise visualization of DNA sequences on metaphase chromosomes and interphase nuclei. These techniques can be used to identify chromosomes, detect chromosomal aberrations, and analyze linear and spetial genome organization. FISH procedures are also used to clinical fields for diagnosis of disease-related chromosome changes and tumor biology.

  13. Linear optimal control of tokamak fusion devices

    Energy Technology Data Exchange (ETDEWEB)

    Kessel, C.E.; Firestone, M.A.; Conn, R.W.

    1989-05-01

    The control of plasma position, shape and current in a tokamak fusion reactor is examined using linear optimal control. These advanced tokamaks are characterized by non up-down symmetric coils and structure, thick structure surrounding the plasma, eddy currents, shaped plasmas, superconducting coils, vertically unstable plasmas, and hybrid function coils providing ohmic heating, vertical field, radial field, and shaping field. Models of the electromagnetic environment in a tokamak are derived and used to construct control gains that are tested in nonlinear simulations with initial perturbations. The issues of applying linear optimal control to advanced tokamaks are addressed, including complex equilibrium control, choice of cost functional weights, the coil voltage limit, discrete control, and order reduction. Results indicate that the linear optimal control is a feasible technique for controlling advanced tokamaks where the more common classical control will be severely strained or will not work. 28 refs., 13 figs.

  14. Non linear system become linear system

    Directory of Open Access Journals (Sweden)

    Petre Bucur

    2007-01-01

    Full Text Available The present paper refers to the theory and the practice of the systems regarding non-linear systems and their applications. We aimed the integration of these systems to elaborate their response as well as to highlight some outstanding features.

  15. Photochromic organic-inorganic hybrid materials.

    Science.gov (United States)

    Pardo, Rosario; Zayat, Marcos; Levy, David

    2011-02-01

    Photochromic organic-inorganic hybrid materials have attracted considerable attention owing to their potential application in photoactive devices, such as optical memories, windows, photochromic decorations, optical switches, filters or non-linear optics materials. The growing interest in this field has largely expanded the use of photochromic materials for the purpose of improving existing materials and exploring new photochromic hybrid systems. This tutorial review summarizes the design and preparation of photochromic hybrid materials, and particularly those based on the incorporation of organic molecules in organic-inorganic matrices by the sol-gel method. This is the most commonly used method for the preparation of these materials as it allows vitreous hybrid materials to be obtained at low temperatures, and controls the interaction between the organic molecule and its embedding matrix, and hence allows tailoring of the performance of the resulting devices.

  16. A multiconfigurational hybrid density-functional theory

    CERN Document Server

    Sharkas, Kamal; Jensen, Hans Jørgen Aa; Toulouse, Julien; 10.1063/1.4733672

    2012-01-01

    We propose a multiconfigurational hybrid density-functional theory which rigorously combines a multiconfiguration self-consistent-field calculation with a density-functional approximation based on a linear decomposition of the electron-electron interaction. This gives a straightforward extension of the usual hybrid approximations by essentially adding a fraction \\lambda of exact static correlation in addition to the fraction \\lambda of exact exchange. Test calculations on the cycloaddition reactions of ozone with ethylene or acetylene and the dissociation of diatomic molecules with the Perdew-Burke-Ernzerhof (PBE) and Becke-Lee-Yang-Parr (BLYP) density functionals show that a good value of \\lambda is 0.25, as in the usual hybrid approximations. The results suggest that the proposed multiconfigurational hybrid approximations can improve over usual density-functional calculations for situations with strong static correlation effects.

  17. Atom-Light Hybrid Interferometer.

    Science.gov (United States)

    Chen, Bing; Qiu, Cheng; Chen, Shuying; Guo, Jinxian; Chen, L Q; Ou, Z Y; Zhang, Weiping

    2015-07-24

    A new type of hybrid atom-light interferometer is demonstrated with atomic Raman amplification processes replacing the beam splitting elements in a traditional interferometer. This nonconventional interferometer involves correlated optical and atomic waves in the two arms. The correlation between atoms and light developed with the Raman process makes this interferometer different from conventional interferometers with linear beam splitters. It is observed that the high-contrast interference fringes are sensitive to the optical phase via a path change as well as the atomic phase via a magnetic field change. This new atom-light correlated hybrid interferometer is a sensitive probe of the atomic internal state and should find wide applications in precision measurement and quantum control with atoms and photons.

  18. Screening and Confirmation of Phthalates in Food Contact Materials by Hybrid Linear Ion Trap/Orbitrap Mass Spectrometry%食品接触材料中邻苯二甲酸酯的LTQ-Orbitrap组合式高分辨质谱快速筛查和确证

    Institute of Scientific and Technical Information of China (English)

    王晓兵; 丁利; 朱绍华; 戴华; 许宙; 焦艳娜; 王利岳

    2011-01-01

    A fast screening and conformation method of phthalates in food contact materials based on liquid chromatography mass spectrometry using a linear ion trap-orbitrap hybrid instrument at high mass resolution(HPLC-LTQ-Oribitrap/MS) was developed.Accelerated s%建立了食品接触材料中邻苯二甲酸酯快速筛查确证的高效液相色谱-高分辨质谱法(HPLC-LTQ-Orbi-trap/MS)。实验中采用加速溶剂萃取(ASE)法为样品前处理手段,优化了萃取溶剂、萃取温度、静态萃取时间等实验参数,提高了食品接触材料中邻苯二甲酸酯的提取效率。采用高分辨质谱有效地去除了基体干扰,通过静电场轨道阱全扫描得到的精确相对分子质量进行了化合物的定量,用离子阱的二级质谱图对未知化合物进行了进一步确证。结果表明:邻苯二甲酸酯的检测限为1 ng/mL;该方法的加标回收率为89.8%~101.3%,

  19. Linear collider: a preview

    Energy Technology Data Exchange (ETDEWEB)

    Wiedemann, H.

    1981-11-01

    Since no linear colliders have been built yet it is difficult to know at what energy the linear cost scaling of linear colliders drops below the quadratic scaling of storage rings. There is, however, no doubt that a linear collider facility for a center of mass energy above say 500 GeV is significantly cheaper than an equivalent storage ring. In order to make the linear collider principle feasible at very high energies a number of problems have to be solved. There are two kinds of problems: one which is related to the feasibility of the principle and the other kind of problems is associated with minimizing the cost of constructing and operating such a facility. This lecture series describes the problems and possible solutions. Since the real test of a principle requires the construction of a prototype I will in the last chapter describe the SLC project at the Stanford Linear Accelerator Center.

  20. Basic linear algebra

    CERN Document Server

    Blyth, T S

    2002-01-01

    Basic Linear Algebra is a text for first year students leading from concrete examples to abstract theorems, via tutorial-type exercises. More exercises (of the kind a student may expect in examination papers) are grouped at the end of each section. The book covers the most important basics of any first course on linear algebra, explaining the algebra of matrices with applications to analytic geometry, systems of linear equations, difference equations and complex numbers. Linear equations are treated via Hermite normal forms which provides a successful and concrete explanation of the notion of linear independence. Another important highlight is the connection between linear mappings and matrices leading to the change of basis theorem which opens the door to the notion of similarity. This new and revised edition features additional exercises and coverage of Cramer's rule (omitted from the first edition). However, it is the new, extra chapter on computer assistance that will be of particular interest to readers:...

  1. Linearity in Process Languages

    DEFF Research Database (Denmark)

    Nygaard, Mikkel; Winskel, Glynn

    2002-01-01

    The meaning and mathematical consequences of linearity (managing without a presumed ability to copy) are studied for a path-based model of processes which is also a model of affine-linear logic. This connection yields an affine-linear language for processes, automatically respecting open-map bisi......The meaning and mathematical consequences of linearity (managing without a presumed ability to copy) are studied for a path-based model of processes which is also a model of affine-linear logic. This connection yields an affine-linear language for processes, automatically respecting open......-map bisimulation, in which a range of process operations can be expressed. An operational semantics is provided for the tensor fragment of the language. Different ways to make assemblies of processes lead to different choices of exponential, some of which respect bisimulation....

  2. Matrices and linear transformations

    CERN Document Server

    Cullen, Charles G

    1990-01-01

    ""Comprehensive . . . an excellent introduction to the subject."" - Electronic Engineer's Design Magazine.This introductory textbook, aimed at sophomore- and junior-level undergraduates in mathematics, engineering, and the physical sciences, offers a smooth, in-depth treatment of linear algebra and matrix theory. The major objects of study are matrices over an arbitrary field. Contents include Matrices and Linear Systems; Vector Spaces; Determinants; Linear Transformations; Similarity: Part I and Part II; Polynomials and Polynomial Matrices; Matrix Analysis; and Numerical Methods. The first

  3. Adding linear orders

    CERN Document Server

    Shelah, Saharon

    2011-01-01

    We address the following question: Can we expand an NIP theory by adding a linear order such that the expansion is still NIP? Easily, if acl(A)=A for all A, then this is true. Otherwise, we give counterexamples. More precisely, there is a totally categorical theory for which every expansion by a linear order has IP. There is also an \\omega-stable NDOP theory for which every expansion by a linear order interprets bounded arithmetic.

  4. Efficient Non Linear Loudspeakers

    DEFF Research Database (Denmark)

    Petersen, Bo R.; Agerkvist, Finn T.

    2006-01-01

    Loudspeakers have traditionally been designed to be as linear as possible. However, as techniques for compensating non linearities are emerging, it becomes possible to use other design criteria. This paper present and examines a new idea for improving the efficiency of loudspeakers at high levels...... by changing the voice coil layout. This deliberate non-linear design has the benefit that a smaller amplifier can be used, which has the benefit of reducing system cost as well as reducing power consumption....

  5. Linear integrated circuits

    CERN Document Server

    Carr, Joseph

    1996-01-01

    The linear IC market is large and growing, as is the demand for well trained technicians and engineers who understand how these devices work and how to apply them. Linear Integrated Circuits provides in-depth coverage of the devices and their operation, but not at the expense of practical applications in which linear devices figure prominently. This book is written for a wide readership from FE and first degree students, to hobbyists and professionals.Chapter 1 offers a general introduction that will provide students with the foundations of linear IC technology. From chapter 2 onwa

  6. Charges for linearized gravity

    CERN Document Server

    Aksteiner, Steffen

    2013-01-01

    Maxwell test fields as well as solutions of linearized gravity on the Kerr exterior admit non-radiating modes, i.e. non-trivial time-independent solutions. These are closely related to conserved charges. In this paper we discuss the non-radiating modes for linearized gravity, which may be seen to correspond to the Poincare Lie-algebra. The 2-dimensional isometry group of Kerr corresponds to a 2-parameter family of gauge-invariant non-radiating modes representing infinitesimal perturbations of mass and azimuthal angular momentum. We calculate the linearized mass charge in terms of linearized Newman-Penrose scalars.

  7. Recombineering linear BACs.

    Science.gov (United States)

    Chen, Qingwen; Narayanan, Kumaran

    2015-01-01

    Recombineering is a powerful genetic engineering technique based on homologous recombination that can be used to accurately modify DNA independent of its sequence or size. One novel application of recombineering is the assembly of linear BACs in E. coli that can replicate autonomously as linear plasmids. A circular BAC is inserted with a short telomeric sequence from phage N15, which is subsequently cut and rejoined by the phage protelomerase enzyme to generate a linear BAC with terminal hairpin telomeres. Telomere-capped linear BACs are protected against exonuclease attack both in vitro and in vivo in E. coli cells and can replicate stably. Here we describe step-by-step protocols to linearize any BAC clone by recombineering, including inserting and screening for presence of the N15 telomeric sequence, linearizing BACs in vivo in E. coli, extracting linear BACs, and verifying the presence of hairpin telomere structures. Linear BACs may be useful for functional expression of genomic loci in cells, maintenance of linear viral genomes in their natural conformation, and for constructing innovative artificial chromosome structures for applications in mammalian and plant cells.

  8. Fault tolerant linear actuator

    Science.gov (United States)

    Tesar, Delbert

    2004-09-14

    In varying embodiments, the fault tolerant linear actuator of the present invention is a new and improved linear actuator with fault tolerance and positional control that may incorporate velocity summing, force summing, or a combination of the two. In one embodiment, the invention offers a velocity summing arrangement with a differential gear between two prime movers driving a cage, which then drives a linear spindle screw transmission. Other embodiments feature two prime movers driving separate linear spindle screw transmissions, one internal and one external, in a totally concentric and compact integrated module.

  9. Linear models with R

    CERN Document Server

    Faraway, Julian J

    2014-01-01

    A Hands-On Way to Learning Data AnalysisPart of the core of statistics, linear models are used to make predictions and explain the relationship between the response and the predictors. Understanding linear models is crucial to a broader competence in the practice of statistics. Linear Models with R, Second Edition explains how to use linear models in physical science, engineering, social science, and business applications. The book incorporates several improvements that reflect how the world of R has greatly expanded since the publication of the first edition.New to the Second EditionReorganiz

  10. Linear Rogue waves

    CERN Document Server

    Yuce, C

    2015-01-01

    We predict the existence of linear discrete rogue waves. We discuss that Josephson effect is the underlying reason for the formation of such waves. We study linear rogue waves in continuous system and present an exact analytical rogue wave solution of the Schrodinger-like equation.

  11. Linearized Wenger graphs

    OpenAIRE

    2014-01-01

    © 2015 Elsevier B.V. Motivated by recent extensive studies on Wenger graphs, we introduce a new infinite class of bipartite graphs of a similar type, called linearized Wenger graphs. The spectrum, diameter and girth of these linearized Wenger graphs are determined.

  12. Efficient Proof Engines for Bounded Model Checking of Hybrid Systems

    DEFF Research Database (Denmark)

    Fränzle, Martin; Herde, Christian

    2005-01-01

    In this paper we present HySat, a new bounded model checker for linear hybrid systems, incorporating a tight integration of a DPLL-based pseudo-Boolean SAT solver and a linear programming routine as core engine. In contrast to related tools like MathSAT, ICS, or CVC, our tool exploits all...

  13. Efficient Non Linear Loudspeakers

    DEFF Research Database (Denmark)

    Petersen, Bo R.; Agerkvist, Finn T.

    2006-01-01

    Loudspeakers have traditionally been designed to be as linear as possible. However, as techniques for compensating non linearities are emerging, it becomes possible to use other design criteria. This paper present and examines a new idea for improving the efficiency of loudspeakers at high levels...... by changing the voice coil layout. This deliberate non-linear design has the benefit that a smaller amplifier can be used, which has the benefit of reducing system cost as well as reducing power consumption.......Loudspeakers have traditionally been designed to be as linear as possible. However, as techniques for compensating non linearities are emerging, it becomes possible to use other design criteria. This paper present and examines a new idea for improving the efficiency of loudspeakers at high levels...

  14. Linear algebra done right

    CERN Document Server

    Axler, Sheldon

    2015-01-01

    This best-selling textbook for a second course in linear algebra is aimed at undergrad math majors and graduate students. The novel approach taken here banishes determinants to the end of the book. The text focuses on the central goal of linear algebra: understanding the structure of linear operators on finite-dimensional vector spaces. The author has taken unusual care to motivate concepts and to simplify proofs. A variety of interesting exercises in each chapter helps students understand and manipulate the objects of linear algebra. The third edition contains major improvements and revisions throughout the book. More than 300 new exercises have been added since the previous edition. Many new examples have been added to illustrate the key ideas of linear algebra. New topics covered in the book include product spaces, quotient spaces, and dual spaces. Beautiful new formatting creates pages with an unusually pleasant appearance in both print and electronic versions. No prerequisites are assumed other than the ...

  15. From hybrid swarms to swarms of hybrids

    Science.gov (United States)

    The introgression of modern humans (Homo sapiens) with Neanderthals 40,000 YBP after a half-million years of separation, may have led to the best example of a hybrid swarm on earth. Modern trade and transportation in support of the human hybrids has continued to introduce additional species, genotyp...

  16. The Hybrid Museum: Hybrid Economies of Meaning

    DEFF Research Database (Denmark)

    Vestergaard, Vitus

    2013-01-01

    this article shows that there are two different museum mindsets where the second mindset leans towards participatory practices. It is shown how a museum can support a hybrid economy of meaning that builds on both a user generated economy of meaning and an institutional economy of meaning and adds value to both....... Such a museum is referred to as a hybrid museum....

  17. Hydraulic Hybrid Vehicles

    Science.gov (United States)

    EPA and the United Parcel Service (UPS) have developed a hydraulic hybrid delivery vehicle to explore and demonstrate the environmental benefits of the hydraulic hybrid for urban pick-up and delivery fleets.

  18. Hybrid Management in Hospitals

    DEFF Research Database (Denmark)

    Byrkjeflot, Haldor; Jespersen, Peter Kragh

    2010-01-01

    Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer......Artiklen indeholder et litteraturbaseret studium af ledelsesformer i sygehuse, hvor sundhedsfaglig ledelse og generel ledelse mikses til hybride ledelsesformer...

  19. An IIR median hybrid filter

    Science.gov (United States)

    Bauer, Peter H.; Sartori, Michael A.; Bryden, Timothy M.

    1992-01-01

    A new class of nonlinear filters, the so-called class of multidirectional infinite impulse response median hybrid filters, is presented and analyzed. The input signal is processed twice using a linear shift-invariant infinite impulse response filtering module: once with normal causality and a second time with inverted causality. The final output of the MIMH filter is the median of the two-directional outputs and the original input signal. Thus, the MIMH filter is a concatenation of linear filtering and nonlinear filtering (a median filtering module). Because of this unique scheme, the MIMH filter possesses many desirable properties which are both proven and analyzed (including impulse removal, step preservation, and noise suppression). A comparison to other existing median type filters is also provided.

  20. Super-hybrid composites - An emerging structural material

    Science.gov (United States)

    Chamis, C. C.; Lark, R. F.; Sullivan, T. L.

    1975-01-01

    Specimens of super-hybrids and advanced fiber composites were subjected to extensive tests to determine their mechanical properties, including impact and thermal fatigue. The super-hybrids were fabricated by a procedure similar to that reported by Chamis et al., (1975). Super-hybrids subjected to 1000 cycles of thermal fatigue from -100 to 300 F retained over 90% of their longitudinal flexural strength and over 75% of their transverse flexural strength; their transverse flexural strength may be as high as 8 times that of a commercially supplied boron/1100-Al composite. The thin specimen Izod longitudinal impact resistance of the super-hybrids was twice that of the boron/110-Al material. Super-hybrids subjected to transverse tensile loads exhibited nonlinear stress-strain relationships. The experimentally determined initial membrane (in-plane) and bending elastic properties of super-hybrids were predicted adequately by linear laminate analysis.

  1. Resin Catalyst Hybrids

    Institute of Scientific and Technical Information of China (English)

    S. Asaoka

    2005-01-01

    @@ 1Introduction: What are resin catalyst hybrids? There are typically two types of resin catalyst. One is acidic resin which representative is polystyrene sulfonic acid. The other is basic resin which is availed as metal complex support. The objective items of this study on resin catalyst are consisting of pellet hybrid, equilibrium hybrid and function hybrid of acid and base,as shown in Fig. 1[1-5].

  2. Mesoscale hybrid calibration artifact

    Science.gov (United States)

    Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.

    2010-09-07

    A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.

  3. Linearized FUN3D for Rapid Aeroelastic and Aeroservoelastic Design and Analysis Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The overall objective of this Phase I project is to develop a hybrid approach in FUN3D, referred herein to as the Linearized FUN3D, for rapid aeroelastic and...

  4. Realizing the Hybrid Library.

    Science.gov (United States)

    Pinfield, Stephen; Eaton, Jonathan; Edwards, Catherine; Russell, Rosemary; Wissenburg, Astrid; Wynne, Peter

    1998-01-01

    Outlines five projects currently funded by the United Kingdom's Electronic Libraries Program (eLib): HyLiFe (Hybrid Library of the Future), MALIBU (MAnaging the hybrid Library for the Benefit of Users), HeadLine (Hybrid Electronic Access and Delivery in the Library Networked Environment), ATHENS (authentication scheme), and BUILDER (Birmingham…

  5. Homoploid hybrid expectations

    Science.gov (United States)

    Homoploid hybrid speciation occurs when a stable, fertile, and reproductively isolated lineage results from hybridization between two distinct species without a change in ploidy level. Reproductive isolation between a homoploid hybrid species and its parents is generally attained via chromosomal re...

  6. Hybrid armature projectile

    Science.gov (United States)

    Hawke, Ronald S.; Asay, James R.; Hall, Clint A.; Konrad, Carl H.; Sauve, Gerald L.; Shahinpoor, Mohsen; Susoeff, Allan R.

    1993-01-01

    A projectile for a railgun that uses a hybrid armature and provides a seed block around part of the outer surface of the projectile to seed the hybrid plasma brush. In addition, the hybrid armature is continuously vaporized to replenish plasma in a plasma armature to provide a tandem armature and provides a unique ridge and groove to reduce plasama blowby.

  7. Intraply Hybrid Composite Design

    Science.gov (United States)

    Chamis, C. C.; Sinclair, J. H.

    1986-01-01

    Several theoretical approaches combined in program. Intraply hybrid composites investigated theoretically and experimentally at Lewis Research Center. Theories developed during investigations and corroborated by attendant experiments used to develop computer program identified as INHYD (Intraply Hybrid Composite Design). INHYD includes several composites micromechanics theories, intraply hybrid composite theories, and integrated hygrothermomechanical theory. Equations from theories used by program as appropriate for user's specific applications.

  8. Hybrid quantum information processing

    Energy Technology Data Exchange (ETDEWEB)

    Furusawa, Akira [Department of Applied Physics, School of Engineering, The University of Tokyo (Japan)

    2014-12-04

    I will briefly explain the definition and advantage of hybrid quantum information processing, which is hybridization of qubit and continuous-variable technologies. The final goal would be realization of universal gate sets both for qubit and continuous-variable quantum information processing with the hybrid technologies. For that purpose, qubit teleportation with a continuousvariable teleporter is one of the most important ingredients.

  9. Matrices and linear algebra

    CERN Document Server

    Schneider, Hans

    1989-01-01

    Linear algebra is one of the central disciplines in mathematics. A student of pure mathematics must know linear algebra if he is to continue with modern algebra or functional analysis. Much of the mathematics now taught to engineers and physicists requires it.This well-known and highly regarded text makes the subject accessible to undergraduates with little mathematical experience. Written mainly for students in physics, engineering, economics, and other fields outside mathematics, the book gives the theory of matrices and applications to systems of linear equations, as well as many related t

  10. Applied linear regression

    CERN Document Server

    Weisberg, Sanford

    2013-01-01

    Praise for the Third Edition ""...this is an excellent book which could easily be used as a course text...""-International Statistical Institute The Fourth Edition of Applied Linear Regression provides a thorough update of the basic theory and methodology of linear regression modeling. Demonstrating the practical applications of linear regression analysis techniques, the Fourth Edition uses interesting, real-world exercises and examples. Stressing central concepts such as model building, understanding parameters, assessing fit and reliability, and drawing conclusions, the new edition illus

  11. Elements of linear space

    CERN Document Server

    Amir-Moez, A R; Sneddon, I N

    1962-01-01

    Elements of Linear Space is a detailed treatment of the elements of linear spaces, including real spaces with no more than three dimensions and complex n-dimensional spaces. The geometry of conic sections and quadric surfaces is considered, along with algebraic structures, especially vector spaces and transformations. Problems drawn from various branches of geometry are given.Comprised of 12 chapters, this volume begins with an introduction to real Euclidean space, followed by a discussion on linear transformations and matrices. The addition and multiplication of transformations and matrices a

  12. Applied linear regression

    CERN Document Server

    Weisberg, Sanford

    2005-01-01

    Master linear regression techniques with a new edition of a classic text Reviews of the Second Edition: ""I found it enjoyable reading and so full of interesting material that even the well-informed reader will probably find something new . . . a necessity for all of those who do linear regression."" -Technometrics, February 1987 ""Overall, I feel that the book is a valuable addition to the now considerable list of texts on applied linear regression. It should be a strong contender as the leading text for a first serious course in regression analysis."" -American Scientist, May-June 1987

  13. Linear associative algebras

    CERN Document Server

    Abian, Alexander

    1973-01-01

    Linear Associative Algebras focuses on finite dimensional linear associative algebras and the Wedderburn structure theorems.The publication first elaborates on semigroups and groups, rings and fields, direct sum and tensor product of rings, and polynomial and matrix rings. The text then ponders on vector spaces, including finite dimensional vector spaces and matrix representation of vectors. The book takes a look at linear associative algebras, as well as the idempotent and nilpotent elements of an algebra, ideals of an algebra, total matrix algebras and the canonical forms of matrices, matrix

  14. Characterization of well-posedness of piecewise linear systems

    NARCIS (Netherlands)

    Imura, J.-I.; Schaft, van der A.J.

    1998-01-01

    One of the basic issues in the study of hybrid systems is the well-posedness (existence and uniqueness of solutions) problem of discontinuous dynamical systems. This paper addresses this problem for a class of piecewise-linear discontinuous systems under the definition of solutions of Carath\\'eodory

  15. Characterization of well-posedness of piecewise linear systems

    NARCIS (Netherlands)

    Imura, Jun-ichi; Schaft, van der Arjan

    2000-01-01

    One of the basic issues in the study of hybrid systems is the well-posedness (existence and uniqueness of solutions) problem of discontinuous dynamical systems. The paper addresses this problem for a class of piecewise-linear discontinuous systems under the definition of solutions of Caratheodory. T

  16. Characterization of Well-Posedness of Piecewise-Linear Systems

    NARCIS (Netherlands)

    Imura, Jun-ichi; Schaft, Arjan van der

    2000-01-01

    One of the basic issues in the study of hybrid systems is the well-posedness (existence and uniqueness of solutions) problem of discontinuous dynamical systems. The paper addresses this problem for a class of piecewise-linear discontinuous systems under the definition of solutions of Carathéodory. T

  17. Constructing Hybrid Baryons with Flux Tubes

    CERN Document Server

    Capstick, Simon; Capstick, Simon; Page, Philip R.

    1999-01-01

    Hybrid baryon states are described in quark potential models as having explicit excitation of the gluon degrees of freedom. Such states are described in a model motivated by the strong coupling limit of Hamiltonian lattice gauge theory, where three flux tubes meeting at a junction play the role of the glue. The adiabatic approximation for the quark motion is used, and the flux tubes and junction are modeled by beads which are attracted to each other and the quarks by a linear potential, and vibrate in various string modes. Quantum numbers and estimates of the energies of the lightest hybrid baryons are provided.

  18. A hybrid Scatter/Transform cloaking model

    Directory of Open Access Journals (Sweden)

    Gad Licht

    2015-01-01

    Full Text Available A new Scatter/Transform cloak is developed that combines the light bending of refraction characteristic of a Transform cloak with the scatter cancellation characteristic of a Scatter cloak. The hybrid cloak incorporates both Transform’s variable index of refraction with modified linear intrusions to maximize the Scatter cloak effect. Scatter/Transform improved the scattering cross-section of cloaking in a 2-dimensional space to 51.7% compared to only 39.6% or 45.1% respectively with either Scatter or Transform alone. Metamaterials developed with characteristics based on the new ST hybrid cloak will exhibit superior cloaking capabilities.

  19. Optical linear algebra processors - Architectures and algorithms

    Science.gov (United States)

    Casasent, David

    1986-01-01

    Attention is given to the component design and optical configuration features of a generic optical linear algebra processor (OLAP) architecture, as well as the large number of OLAP architectures, number representations, algorithms and applications encountered in current literature. Number-representation issues associated with bipolar and complex-valued data representations, high-accuracy (including floating point) performance, and the base or radix to be employed, are discussed, together with case studies on a space-integrating frequency-multiplexed architecture and a hybrid space-integrating and time-integrating multichannel architecture.

  20. Optical linear algebra processors - Architectures and algorithms

    Science.gov (United States)

    Casasent, David

    1986-01-01

    Attention is given to the component design and optical configuration features of a generic optical linear algebra processor (OLAP) architecture, as well as the large number of OLAP architectures, number representations, algorithms and applications encountered in current literature. Number-representation issues associated with bipolar and complex-valued data representations, high-accuracy (including floating point) performance, and the base or radix to be employed, are discussed, together with case studies on a space-integrating frequency-multiplexed architecture and a hybrid space-integrating and time-integrating multichannel architecture.

  1. Gravity localization on hybrid branes

    Energy Technology Data Exchange (ETDEWEB)

    Veras, D.F.S., E-mail: franklin@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Caixa Postal 6030, 60455-760, Fortaleza, Ceará (Brazil); Cruz, W.T., E-mail: wilamicruz@gmail.com [Instituto Federal de Educação, Ciência e Tecnologia do Ceará (IFCE), Campus Juazeiro do Norte, 63040-540 Juazeiro do Norte, Ceará (Brazil); Maluf, R.V., E-mail: r.v.maluf@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Caixa Postal 6030, 60455-760, Fortaleza, Ceará (Brazil); Almeida, C.A.S., E-mail: carlos@fisica.ufc.br [Universidade Federal do Ceará (UFC), Departamento de Física, Campus do Pici, Caixa Postal 6030, 60455-760, Fortaleza, Ceará (Brazil)

    2016-03-10

    This work deals with gravity localization on codimension-1 brane worlds engendered by compacton-like kinks, the so-called hybrid branes. In such scenarios, the thin brane behavior is manifested when the extra dimension is outside the compact domain, where the energy density is non-trivial, instead of asymptotically as in the usual thick brane models. The zero mode is trapped in the brane, as required. The massive modes, although not localized in the brane, have important phenomenological implications such as corrections to the Newton's law. We study such corrections in the usual thick domain wall and in the hybrid brane scenarios. By means of suitable numerical methods, we attain the mass spectrum for the graviton and the corresponding wavefunctions. The spectra possess the usual linearly increasing behavior from the Kaluza–Klein theories. Further, we show that the 4D gravitational force is slightly increased at short distances. The first eigenstate contributes highly for the correction to the Newton's law. The subsequent normalized solutions have diminishing contributions. Moreover, we find out that the phenomenology of the hybrid brane is not different from the usual thick domain wall. The use of numerical techniques for solving the equations of the massive modes is useful for matching possible phenomenological measurements in the gravitational law as a probe to warped extra dimensions.

  2. Gravity localization on hybrid branes

    Science.gov (United States)

    Veras, D. F. S.; Cruz, W. T.; Maluf, R. V.; Almeida, C. A. S.

    2016-03-01

    This work deals with gravity localization on codimension-1 brane worlds engendered by compacton-like kinks, the so-called hybrid branes. In such scenarios, the thin brane behavior is manifested when the extra dimension is outside the compact domain, where the energy density is non-trivial, instead of asymptotically as in the usual thick brane models. The zero mode is trapped in the brane, as required. The massive modes, although not localized in the brane, have important phenomenological implications such as corrections to the Newton's law. We study such corrections in the usual thick domain wall and in the hybrid brane scenarios. By means of suitable numerical methods, we attain the mass spectrum for the graviton and the corresponding wavefunctions. The spectra possess the usual linearly increasing behavior from the Kaluza-Klein theories. Further, we show that the 4D gravitational force is slightly increased at short distances. The first eigenstate contributes highly for the correction to the Newton's law. The subsequent normalized solutions have diminishing contributions. Moreover, we find out that the phenomenology of the hybrid brane is not different from the usual thick domain wall. The use of numerical techniques for solving the equations of the massive modes is useful for matching possible phenomenological measurements in the gravitational law as a probe to warped extra dimensions.

  3. Hybrid manifold embedding.

    Science.gov (United States)

    Liu, Yang; Liu, Yan; Chan, Keith C C; Hua, Kien A

    2014-12-01

    In this brief, we present a novel supervised manifold learning framework dubbed hybrid manifold embedding (HyME). Unlike most of the existing supervised manifold learning algorithms that give linear explicit mapping functions, the HyME aims to provide a more general nonlinear explicit mapping function by performing a two-layer learning procedure. In the first layer, a new clustering strategy called geodesic clustering is proposed to divide the original data set into several subsets with minimum nonlinearity. In the second layer, a supervised dimensionality reduction scheme called locally conjugate discriminant projection is performed on each subset for maximizing the discriminant information and minimizing the dimension redundancy simultaneously in the reduced low-dimensional space. By integrating these two layers in a unified mapping function, a supervised manifold embedding framework is established to describe both global and local manifold structure as well as to preserve the discriminative ability in the learned subspace. Experiments on various data sets validate the effectiveness of the proposed method.

  4. Unsupervised Linear Discriminant Analysis

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    An algorithm for unsupervised linear discriminant analysis was presented. Optimal unsupervised discriminant vectors are obtained through maximizing covariance of all samples and minimizing covariance of local k-nearest neighbor samples. The experimental results show our algorithm is effective.

  5. Isolated linear blaschkoid psoriasis.

    Science.gov (United States)

    Nasimi, M; Abedini, R; Azizpour, A; Nikoo, A

    2016-10-01

    Linear psoriasis (LPs) is considered a rare clinical presentation of psoriasis, which is characterized by linear erythematous and scaly lesions along the lines of Blaschko. We report the case of a 20-year-old man who presented with asymptomatic linear and S-shaped erythematous, scaly plaques on right side of his trunk. The plaques were arranged along the lines of Blaschko with a sharp demarcation at the midline. Histological examination of a skin biopsy confirmed the diagnosis of psoriasis. Topical calcipotriol and betamethasone dipropionate ointments were prescribed for 2 months. A good clinical improvement was achieved, with reduction in lesion thickness and scaling. In patients with linear erythematous and scaly plaques along the lines of Blaschko, the diagnosis of LPs should be kept in mind, especially in patients with asymptomatic lesions of late onset. © 2016 British Association of Dermatologists.

  6. Linear systems theory revisited

    NARCIS (Netherlands)

    Willigenburg, van L.G.; Koning, de W.L.

    2008-01-01

    This paper investigates and clarifies how different definitions of reachability, observability, controllability, reconstructability and minimality that appear in the control literature, may be equivalent or different, depending on the type of linear system. The differences are caused by (1) whether

  7. Original Framework for Optimizing Hybrid Energy Supply

    Directory of Open Access Journals (Sweden)

    Amevi Acakpovi

    2016-01-01

    Full Text Available This paper proposes an original framework for optimizing hybrid energy systems. The recent growth of hybrid energy systems in remote areas across the world added to the increasing cost of renewable energy has triggered the inevitable development of hybrid energy systems. Hybrid energy systems always pose a problem of optimization of cost which has been approached with different perspectives in the recent past. This paper proposes a framework to guide the techniques of optimizing hybrid energy systems in general. The proposed framework comprises four stages including identification of input variables for energy generation, establishment of models of energy generation by individual sources, development of artificial intelligence, and finally summation of selected sources. A case study of a solar, wind, and hydro hybrid system was undertaken with a linear programming approach. Substantial results were obtained with regard to how load requests were constantly satisfied while minimizing the cost of electricity. The developed framework gained its originality from the fact that it has included models of individual sources of energy that even make the optimization problem more complex. This paper also has impacts on the development of policies which will encourage the integration and development of renewable energies.

  8. Elementary linear algebra

    CERN Document Server

    Andrilli, Stephen

    2010-01-01

    Elementary Linear Algebra develops and explains in careful detail the computational techniques and fundamental theoretical results central to a first course in linear algebra. This highly acclaimed text focuses on developing the abstract thinking essential for further mathematical study. The authors give early, intensive attention to the skills necessary to make students comfortable with mathematical proofs. The text builds a gradual and smooth transition from computational results to general theory of abstract vector spaces. It also provides flexbile coverage of practical applications, expl

  9. Linear system theory

    Science.gov (United States)

    Callier, Frank M.; Desoer, Charles A.

    1991-01-01

    The aim of this book is to provide a systematic and rigorous access to the main topics of linear state-space system theory in both the continuous-time case and the discrete-time case; and the I/O description of linear systems. The main thrusts of the work are the analysis of system descriptions and derivations of their properties, LQ-optimal control, state feedback and state estimation, and MIMO unity-feedback systems.

  10. Linear Resonance Cooler.

    Science.gov (United States)

    1985-04-01

    7.0 % % o the testing of an experimental linear motor driven expander using a standard production 1/4W split Stirling Common Module compressor. . - o...3 2.2 Expander Design CTI-CRYOGENICS has long recognized the potential of employing a linear drive motor to assist regenerator displacement and...assessment of the expander’s performance with lip seals and clearance seals for a regenerator comprised of nickel balls. Further comparison of a stainless

  11. Dimension of linear models

    DEFF Research Database (Denmark)

    Høskuldsson, Agnar

    1996-01-01

    Determination of the proper dimension of a given linear model is one of the most important tasks in the applied modeling work. We consider here eight criteria that can be used to determine the dimension of the model, or equivalently, the number of components to use in the model. Four...... the basic problems in determining the dimension of linear models. Then each of the eight measures are treated. The results are illustrated by examples....

  12. Cascadable and reconfigurable photonic logic gates based on linear lightwave interference and non-linear phase erasure.

    Science.gov (United States)

    Larom, Bar; Nazarathy, Moshe; Rudnitsky, Arkady; Nevet, Amir; Zalevsky, Zeev

    2010-06-21

    Feasibility of cascading and reconfiguring a pair of linear-nonlinear all-optical logic gate structures is experimentally demonstrated using RF photonics. Progress in highly integrated O/E/O repeaters over Si/InP hybrid platforms enables large-scale reconfigurable gate arrays.

  13. IMPULSE CONTROL HYBRID ELECTRICAL SYSTEM

    Directory of Open Access Journals (Sweden)

    A. A. Lobaty

    2016-01-01

    Full Text Available This paper extends the recently introduced approach for modeling and solving the optimal control problem of fixedswitched mode DC-DC power converter. DCDC converters are a class of electric power circuits that used extensively in regulated DC power supplies, DC motor drives of different types, in Photovoltaic Station energy conversion and other applications due to its advantageous features in terms of size, weight and reliable performance. The main problem in controlling this type converters is in their hybrid nature as the switched circuit topology entails different modes of operation, each of it with its own associated linear continuous-time dynamics.This paper analyses the modeling and controller synthesis of the fixed-frequency buck DC-DC converter, in which the transistor switch is operated by a pulse sequence with constant frequency. In this case the regulation of the DC component of the output voltage is via the duty cycle. The optimization of the control system is based on the formation of the control signal at the output.It is proposed to solve the problem of optimal control of a hybrid system based on the formation of the control signal at the output of the controller, which minimizes a given functional integral quality, which is regarded as a linear quadratic Letov-Kalman functional. Search method of optimal control depends on the type of mathematical model of control object. In this case, we consider a linear deterministic model of the control system, which is common for the majority of hybrid electrical systems. For this formulation of the optimal control problem of search is a problem of analytical design of optimal controller, which has the analytical solution.As an example of the hybrid system is considered a step-down switching DC-DC converter, which is widely used in various electrical systems: as an uninterruptible power supply, battery charger for electric vehicles, the inverter in solar photovoltaic power plants.. A

  14. Constant switching frequency control-based linear-assisted DC/DC regulator for photovoltaic solar-powered facilities

    OpenAIRE

    Martínez García, Herminio; Grau Saldes, Antoni

    2015-01-01

    Hybrid DC-DC regulators or linear–assisted DC-DC regulators are structures that combine both a linear voltage regulator and a switching DC-DC converter. The main objective of this hybrid topology is to converge, in a single circuit topology, the best of both alternatives: One the one hand, obtaining small voltage output ripple, which is typical of linear regulator structures, and, on the other, achieving good energy efficiency, as in switching alternatives. While the linear regulator fixes th...

  15. The hydrogen hybrid option

    Energy Technology Data Exchange (ETDEWEB)

    Smith, J.R.

    1993-10-15

    The energy efficiency of various piston engine options for series hybrid automobiles are compared with conventional, battery powered electric, and proton exchange membrane (PEM) fuel cell hybrid automobiles. Gasoline, compressed natural gas (CNG), and hydrogen are considered for these hybrids. The engine and fuel comparisons are done on a basis of equal vehicle weight, drag, and rolling resistance. The relative emissions of these various fueled vehicle options are also presented. It is concluded that a highly optimized, hydrogen fueled, piston engine, series electric hybrid automobile will have efficiency comparable to a similar fuel cell hybrid automobile and will have fewer total emissions than the battery powered vehicle, even without a catalyst.

  16. Analysis of hybrid systems: An ounce of realism can save an infinity of states

    DEFF Research Database (Denmark)

    Fränzle, Martin

    1999-01-01

    no decision procedures due to inherent undecidability. Thus, unlike finite or timed automata, already linear hybrid automata are out-of-scope of fully automatic verification. In this article, we devise a new semi-decision method for safety of linear and polynomial hybrid systems which may only fail......Hybrid automata have been introduced in both control engineering and computer science as a formal model for the dynamics of hybrid discrete-continuous systems. In the case of so-called linear hybrid automata this formalization supports semi-decision procedures for state reachability, yet...... on pathological, practically uninteresting cases. These remaining cases are such that their safety depends on the complete absence of noise, a situation unlikely to occur in real hybrid systems. Furthermore, we show that if low probability effects of noise are ignored akin to the way they are suppressed...

  17. Hybridization and extinction.

    Science.gov (United States)

    Todesco, Marco; Pascual, Mariana A; Owens, Gregory L; Ostevik, Katherine L; Moyers, Brook T; Hübner, Sariel; Heredia, Sylvia M; Hahn, Min A; Caseys, Celine; Bock, Dan G; Rieseberg, Loren H

    2016-08-01

    Hybridization may drive rare taxa to extinction through genetic swamping, where the rare form is replaced by hybrids, or by demographic swamping, where population growth rates are reduced due to the wasteful production of maladaptive hybrids. Conversely, hybridization may rescue the viability of small, inbred populations. Understanding the factors that contribute to destructive versus constructive outcomes of hybridization is key to managing conservation concerns. Here, we survey the literature for studies of hybridization and extinction to identify the ecological, evolutionary, and genetic factors that critically affect extinction risk through hybridization. We find that while extinction risk is highly situation dependent, genetic swamping is much more frequent than demographic swamping. In addition, human involvement is associated with increased risk and high reproductive isolation with reduced risk. Although climate change is predicted to increase the risk of hybridization-induced extinction, we find little empirical support for this prediction. Similarly, theoretical and experimental studies imply that genetic rescue through hybridization may be equally or more probable than demographic swamping, but our literature survey failed to support this claim. We conclude that halting the introduction of hybridization-prone exotics and restoring mature and diverse habitats that are resistant to hybrid establishment should be management priorities.

  18. Analysis of Seven Drugs in Human Hair by Hybrid Linear Ion Trap/Orbitrap Mass Spectrometry%LTQ-Orbitrap组合式高分辨质谱法快速筛查毛发中7种毒品及代谢物

    Institute of Scientific and Technical Information of China (English)

    叶海英; 郑水庆; 梁晨; 汪蓉; 张玉荣; 张凌怡; 张维冰; 张润生

    2012-01-01

    A new method was developed for the determination of seven illicit drugs and metabolites in human hair by ultra high performance liquid chromatograph tandem a linear ion trap-orbitrap hybrid instrument at high mass resolution (UHPLC-LTQ-Orbitrap/MS). After being washed and grinded, the hair samples were soaked in pH 9. 2 borate buffer with ultrasonic for 90 min. Then the samples were extracted by solid phase extraction (SPE). High resolution mass spectrometry was applied to reduce matrix interference. Full scanning of electrostatic field orbitrap was applied for quantification of drugs. The limits of detection (LOD) of seven illicit drugs and metabolites in human hair were 0. 001 -0. 02 μg/g. The method showed a fairly good linearity over the range of 0. 05 - 50 μg/g (r>0. 9975). The spiked recoveries were between 76. 1% -109. 6% , and the deviation of intra- and inter- day precision was less than 14. 9%. The method is simple, high sensitive, and suitable for the determination of illicit drugs in human hair.%采用超高压液相色谱-二维线性离子阱结合静电场轨道阱组合式高分辨质谱联用技术(Accela U-HPLC/LTQ Orbitrap XL),建立了人毛发中吗啡、O6-单乙酰吗啡、可待因、乙酰可待因、氯胺酮、去甲氯胺酮和美沙酮毒品及代谢物快速筛查方法.取毛发样品经表层清洗后冷冻研磨粉碎,置于硼酸盐缓冲液(pH 9.2)中超声90 min,离心取上清液,用Oasis HLB柱固相萃取制备.通过静电场轨道阱全扫描得到毒品及其代谢物的精确相对分子质量,同时进行7种毒品及其代谢物的快速筛查.高分辨率质谱可有效去除毛发基质干扰,毒品及其代谢物筛查检出限在0.001~0.02 ng/mg,在0.05~50 ng/mg范围内存在良好线性关系(r>0.9975);本方法平均加标回收率为76.1%~109.6%;日内及日间精密度RSD≤14.9%.本方法灵敏度高,样品制备简便,适用于常见毒品的快速筛查.

  19. Spoof Plasmon Hybridization

    CERN Document Server

    Zhang, Jingjing; Luo, Yu; Shen, Xiaopeng; Maier, Stefan A; Cui, Tie Jun

    2016-01-01

    Plasmon hybridization between closely spaced nanoparticles yields new hybrid modes not found in individual constituents, allowing for the engineering of resonance properties and field enhancement capabilities of metallic nanostructure. Experimental verifications of plasmon hybridization have been thus far mostly limited to optical frequencies, as metals cannot support surface plasmons at longer wavelengths. Here, we introduce the concept of 'spoof plasmon hybridization' in highly conductive metal structures and investigate experimentally the interaction of localized surface plasmon resonances (LSPR) in adjacent metal disks corrugated with subwavelength spiral patterns. We show that the hybridization results in the splitting of spoof plasmon modes into bonding and antibonding resonances analogous to molecular orbital rule and plasmonic hybridization in optical spectrum. These hybrid modes can be manipulated to produce enormous field enhancements (larger than 5000) by tuning the separation between disks or alte...

  20. Marine Fish Hybridization

    KAUST Repository

    He, Song

    2017-04-01

    Natural hybridization is reproduction (without artificial influence) between two or more species/populations which are distinguishable from each other by heritable characters. Natural hybridizations among marine fishes were highly underappreciated due to limited research effort; it seems that this phenomenon occurs more often than is commonly recognized. As hybridization plays an important role in biodiversity processes in the marine environment, detecting hybridization events and investigating hybridization is important to understand and protect biodiversity. The first chapter sets the framework for this disseration study. The Cohesion Species Concept was selected as the working definition of a species for this study as it can handle marine fish hybridization events. The concept does not require restrictive species boundaries. A general history and background of natural hybridization in marine fishes is reviewed during in chapter as well. Four marine fish hybridization cases were examed and documented in Chapters 2 to 5. In each case study, at least one diagnostic nuclear marker, screened from among ~14 candidate markers, was found to discriminate the putative hybridizing parent species. To further investigate genetic evidence to support the hybrid status for each hybrid offspring in each case, haploweb analysis on diagnostic markers (nuclear and/or mitochondrial) and the DAPC/PCA analysis on microsatellite data were used. By combining the genetic evidences, morphological traits, and ecological observations together, the potential reasons that triggered each hybridization events and the potential genetic/ecology effects could be discussed. In the last chapter, sequences from 82 pairs of hybridizing parents species (for which COI barcoding sequences were available either on GenBank or in our lab) were collected. By comparing the COI fragment p-distance between each hybridizing parent species, some general questions about marine fish hybridization were discussed: Is

  1. Further linear algebra

    CERN Document Server

    Blyth, T S

    2002-01-01

    Most of the introductory courses on linear algebra develop the basic theory of finite­ dimensional vector spaces, and in so doing relate the notion of a linear mapping to that of a matrix. Generally speaking, such courses culminate in the diagonalisation of certain matrices and the application of this process to various situations. Such is the case, for example, in our previous SUMS volume Basic Linear Algebra. The present text is a continuation of that volume, and has the objective of introducing the reader to more advanced properties of vector spaces and linear mappings, and consequently of matrices. For readers who are not familiar with the contents of Basic Linear Algebra we provide an introductory chapter that consists of a compact summary of the prerequisites for the present volume. In order to consolidate the student's understanding we have included a large num­ ber of illustrative and worked examples, as well as many exercises that are strategi­ cally placed throughout the text. Solutions to the ex...

  2. On Linear Algebra Education

    Directory of Open Access Journals (Sweden)

    Sinan AYDIN

    2009-04-01

    Full Text Available Linear algebra is a basic course followed in mathematics, science, and engineering university departments.Generally, this course is taken in either the first or second year but there have been difficulties in teachingand learning. This type of active algebra has resulted in an increase in research by mathematics educationresearchers. But there is insufficient information on this subject in Turkish and therefore it has not beengiven any educational status. This paper aims to give a general overview of this subject in teaching andlearning. These education studies can be considered quadruple: a the history of linear algebra, b formalismobstacles of linear algebra and cognitive flexibility to improve teaching and learning, c the relation betweenlinear algebra and geometry, d using technology in the teaching and learning linear algebra.Mathematicseducation researchers cannot provide an absolute solution to overcome the teaching and learning difficultiesof linear algebra. Epistemological analyses and experimental teaching have shown the learning difficulties.Given these results, further advice and assistance can be offered locally.

  3. Theory of linear operations

    CERN Document Server

    Banach, S

    1987-01-01

    This classic work by the late Stefan Banach has been translated into English so as to reach a yet wider audience. It contains the basics of the algebra of operators, concentrating on the study of linear operators, which corresponds to that of the linear forms a1x1 + a2x2 + ... + anxn of algebra.The book gathers results concerning linear operators defined in general spaces of a certain kind, principally in Banach spaces, examples of which are: the space of continuous functions, that of the pth-power-summable functions, Hilbert space, etc. The general theorems are interpreted in various mathematical areas, such as group theory, differential equations, integral equations, equations with infinitely many unknowns, functions of a real variable, summation methods and orthogonal series.A new fifty-page section (``Some Aspects of the Present Theory of Banach Spaces'''') complements this important monograph.

  4. Handbook of linear algebra

    CERN Document Server

    Hogben, Leslie

    2013-01-01

    With a substantial amount of new material, the Handbook of Linear Algebra, Second Edition provides comprehensive coverage of linear algebra concepts, applications, and computational software packages in an easy-to-use format. It guides you from the very elementary aspects of the subject to the frontiers of current research. Along with revisions and updates throughout, the second edition of this bestseller includes 20 new chapters.New to the Second EditionSeparate chapters on Schur complements, additional types of canonical forms, tensors, matrix polynomials, matrix equations, special types of

  5. Linear Algebra Thoroughly Explained

    CERN Document Server

    Vujičić, Milan

    2008-01-01

    Linear Algebra Thoroughly Explained provides a comprehensive introduction to the subject suitable for adoption as a self-contained text for courses at undergraduate and postgraduate level. The clear and comprehensive presentation of the basic theory is illustrated throughout with an abundance of worked examples. The book is written for teachers and students of linear algebra at all levels and across mathematics and the applied sciences, particularly physics and engineering. It will also be an invaluable addition to research libraries as a comprehensive resource book for the subject.

  6. Advanced linear algebra

    CERN Document Server

    Cooperstein, Bruce

    2015-01-01

    Advanced Linear Algebra, Second Edition takes a gentle approach that starts with familiar concepts and then gradually builds to deeper results. Each section begins with an outline of previously introduced concepts and results necessary for mastering the new material. By reviewing what students need to know before moving forward, the text builds a solid foundation upon which to progress. The new edition of this successful text focuses on vector spaces and the maps between them that preserve their structure (linear transformations). Designed for advanced undergraduate and beginning graduate stud

  7. Linear- rubbing Manipulation

    Institute of Scientific and Technical Information of China (English)

    SHEN Guo-quan; XIAO Yuan-chun

    2003-01-01

    @@ Linear-rubbing is a characteristic technique in the academic school of internal exercise massage in Shanghai. It was known as "flat pushing method" in the past times. The academic school of internal exercise Tuina finds, in the clinical practice of flat pushing, that if the internal exercise accumuhtes in the palm and one-way movement is replaced by two-way movement, the kinetic energy may be transformed into heat energy, bringing about a new unique manipulating technique, which is rather different from the usual flat pushing no longer and now called linear-rubbing therapy.

  8. Linear Logical Voting Protocols

    DEFF Research Database (Denmark)

    DeYoung, Henry; Schürmann, Carsten

    2012-01-01

    . In response, we promote linear logic as a high-level language for both specifying and implementing voting protocols. Our linear logical specifications of the single-winner first-past-the-post (SW- FPTP) and single transferable vote (STV) protocols demonstrate that this approach leads to concise......Current approaches to electronic implementations of voting protocols involve translating legal text to source code of an imperative programming language. Because the gap between legal text and source code is very large, it is difficult to trust that the program meets its legal specification...... implementations that closely correspond to their legal specification, thereby increasing trust....

  9. Spoken Language Identification Using Hybrid Feature Extraction Methods

    CERN Document Server

    Kumar, Pawan; Mishra, A N; Chandra, Mahesh

    2010-01-01

    This paper introduces and motivates the use of hybrid robust feature extraction technique for spoken language identification (LID) system. The speech recognizers use a parametric form of a signal to get the most important distinguishable features of speech signal for recognition task. In this paper Mel-frequency cepstral coefficients (MFCC), Perceptual linear prediction coefficients (PLP) along with two hybrid features are used for language Identification. Two hybrid features, Bark Frequency Cepstral Coefficients (BFCC) and Revised Perceptual Linear Prediction Coefficients (RPLP) were obtained from combination of MFCC and PLP. Two different classifiers, Vector Quantization (VQ) with Dynamic Time Warping (DTW) and Gaussian Mixture Model (GMM) were used for classification. The experiment shows better identification rate using hybrid feature extraction techniques compared to conventional feature extraction methods.BFCC has shown better performance than MFCC with both classifiers. RPLP along with GMM has shown be...

  10. Filtering and control of stochastic jump hybrid systems

    CERN Document Server

    Yao, Xiuming; Zheng, Wei Xing

    2016-01-01

    This book presents recent research work on stochastic jump hybrid systems. Specifically, the considered stochastic jump hybrid systems include Markovian jump Ito stochastic systems, Markovian jump linear-parameter-varying (LPV) systems, Markovian jump singular systems, Markovian jump two-dimensional (2-D) systems, and Markovian jump repeated scalar nonlinear systems. Some sufficient conditions are first established respectively for the stability and performances of those kinds of stochastic jump hybrid systems in terms of solution of linear matrix inequalities (LMIs). Based on the derived analysis conditions, the filtering and control problems are addressed. The book presents up-to-date research developments and novel methodologies on stochastic jump hybrid systems. The contents can be divided into two parts: the first part is focused on robust filter design problem, while the second part is put the emphasis on robust control problem. These methodologies provide a framework for stability and performance analy...

  11. Analysis of exact linearization and aproximate feedback linearization techniques

    OpenAIRE

    Schnitman, Leizer; Cardoso, Gildeberto de Souza

    2011-01-01

    p. 1-17 This paper presents a study of linear control systems based on exact feedback linearization and approximate feedback linearization. As exact feedback linearization is applied, a linear controller can perform the control objectives. The approximate feedback linearization is required when a nonlinear system presents a noninvolutive property. It uses a Taylor series expansion in order to compute a nonlinear transformation of coordinates to satisfy the involutivity conditions.

  12. Analysis of Exact Linearization and Aproximate Feedback Linearization Techniques

    OpenAIRE

    Cardoso, Gildeberto S.; Leizer Schnitman

    2011-01-01

    This paper presents a study of linear control systems based on exact feedback linearization and approximate feedback linearization. As exact feedback linearization is applied, a linear controller can perform the control objectives. The approximate feedback linearization is required when a nonlinear system presents a noninvolutive property. It uses a Taylor series expansion in order to compute a nonlinear transformation of coordinates to satisfy the involutivity conditions.

  13. Henkin and Hybrid Logic

    DEFF Research Database (Denmark)

    Blackburn, Patrick Rowan; Huertas, Antonia; Manzano, Maria;

    2014-01-01

    Leon Henkin was not a modal logician, but there is a branch of modal logic that has been deeply influenced by his work. That branch is hybrid logic, a family of logics that extend orthodox modal logic with special proposition symbols (called nominals) that name worlds. This paper explains why...... Henkin’s techniques are so important in hybrid logic. We do so by proving a completeness result for a hybrid type theory called HTT, probably the strongest hybrid logic that has yet been explored. Our completeness result builds on earlier work with a system called BHTT, or basic hybrid type theory...... is due to the first-order perspective, which lies at the heart of Henin’s best known work and hybrid logic....

  14. Linear Projective Program Syntax

    NARCIS (Netherlands)

    Bergstra, J.A.; Bethke, I.

    2004-01-01

    Based on an extremely simple program notation more advanced program features can be developed in linear projective program syntax such as conditional statements, while loops, recursion, use of an evaluation stack, object classes, method calls etc. Taking care of a cumulative and bottom up

  15. About Some Linear Operators

    Directory of Open Access Journals (Sweden)

    Ovidiu T. Pop

    2007-01-01

    Full Text Available Using the method of Jakimovski and Leviatan from their work in 1969, we construct a general class of linear positive operators. We study the convergence, the evaluation for the rate of convergence in terms of the first modulus of smoothness and we give a Voronovskaja-type theorem for these operators.

  16. BSA Hybrid Synthesized Polymer

    Institute of Scientific and Technical Information of China (English)

    Zong Bin LIU; Xiao Pei DENG; Chang Sheng ZHAO

    2006-01-01

    Bovine serum albumin (BSA), a naturally occurring biopolymer, was regarded as a polymeric material to graft to an acrylic acid (AA)-N-vinyl pyrrolidone (NVP) copolymer to form a biomacromolecular hybrid polymer. The hybrid polymer can be blended with polyethersulfone (PES) to increase the hydrophilicity of the PES membrane, which suggested that the hybrid polymer might have a wide application in the modification of biomaterials.

  17. Hybrid Action Systems

    DEFF Research Database (Denmark)

    Ronkko, Mauno; Ravn, Anders P.

    1997-01-01

    a differential action, which allows differential equations as primitive actions. The extension allows us to model hybrid systems with both continuous and discrete behaviour. The main result of this paper is an extension of such a hybrid action system with parallel composition. The extension does not change...... the original meaning of the parallel composition, and therefore also the ordinary action systems can be composed in parallel with the hybrid action systems....

  18. HYBRID VEHICLE CONTROL SYSTEM

    Directory of Open Access Journals (Sweden)

    V. Dvadnenko

    2016-06-01

    Full Text Available The hybrid vehicle control system includes a start–stop system for an internal combustion engine. The system works in a hybrid mode and normal vehicle operation. To simplify the start–stop system, there were user new possibilities of a hybrid car, which appeared after the conversion. Results of the circuit design of the proposed system of basic blocks are analyzed.

  19. Nanoscale Organic Hybrid Electrolytes

    KAUST Repository

    Nugent, Jennifer L.

    2010-08-20

    Nanoscale organic hybrid electrolytes are composed of organic-inorganic hybrid nanostructures, each with a metal oxide or metallic nanoparticle core densely grafted with an ion-conducting polyethylene glycol corona - doped with lithium salt. These materials form novel solvent-free hybrid electrolytes that are particle-rich, soft glasses at room temperature; yet manifest high ionic conductivity and good electrochemical stability above 5V. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Hybrid radiator cooling system

    Science.gov (United States)

    France, David M.; Smith, David S.; Yu, Wenhua; Routbort, Jules L.

    2016-03-15

    A method and hybrid radiator-cooling apparatus for implementing enhanced radiator-cooling are provided. The hybrid radiator-cooling apparatus includes an air-side finned surface for air cooling; an elongated vertically extending surface extending outwardly from the air-side finned surface on a downstream air-side of the hybrid radiator; and a water supply for selectively providing evaporative cooling with water flow by gravity on the elongated vertically extending surface.

  1. Linear Mappings of Quaternion Algebra

    OpenAIRE

    Kleyn, Aleks

    2011-01-01

    In the paper I considered linear and antilinear automorphisms of quaternion algebra. I proved the theorem that there is unique expansion of R-linear mapping of quaternion algebra relative to the given set of linear and antilinear automorphisms.

  2. Hybrid Unifying Variable Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    In order to compare new phenomenon of topology change,evolution,hybrid ratio and network characteristics of unified hybrid network theoretical model with unified hybrid supernetwork model,this paper constructed unified hybrid variable supernetwork model(HUVSM).The first layer introduces a hybrid ratio dr,the

  3. Large Unifying Hybrid Supernetwork Model

    Institute of Scientific and Technical Information of China (English)

    LIU; Qiang; FANG; Jin-qing; LI; Yong

    2015-01-01

    For depicting multi-hybrid process,large unifying hybrid network model(so called LUHNM)has two sub-hybrid ratios except dr.They are deterministic hybrid ratio(so called fd)and random hybrid ratio(so called gr),respectively.

  4. Lower hybrid to whistler mode conversion on a density striation

    CERN Document Server

    Camporeale, Enrico; Colestock, Patrick

    2013-01-01

    When a wave packet composed of short wavelength lower hybrid modes traveling in an homogeneous plasma region encounters an inhomogeneity, it can resonantly excite long wavelength whistler waves via a linear mechanism known as mode conversion. An enhancement of lower hybrid/whistler activity has been often observed by sounding rockets and satellites in the presence of density depletions (striations) in the upper ionosphere. We address here the process of linear mode conversion of lower hybrid to whistler waves, mediated by a density striation, using a scalar-field formalism (in the limit of cold plasma linear theory) which we solve numerically. We show that the mode conversion can effectively transfer a large amount of energy from the short to the long wavelength modes. We also study how the efficiency scales by changing the properties (width and amplitude) of the density striation. We present a general criterion for the width of the striation that, if fulfilled, maximizes the conversion efficiency. Such a cri...

  5. Hybrid Rocket Technology

    National Research Council Canada - National Science Library

    Sankaran Venugopal; K K Rajesh; V Ramanujachari

    2011-01-01

    With their unique operational characteristics, hybrid rockets can potentially provide safer, lower-cost avenues for spacecraft and missiles than the current solid propellant and liquid propellant systems...

  6. Hybrid FOSS Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Armstrong researchers are continuing their efforts to further develop FOSS technologies. A hybrid FOSS technique (HyFOSS) employs conventional continuous grating...

  7. Titanium dioxide-cellulose hybrid nanocomposite based conductometric glucose biosensor

    Science.gov (United States)

    Maniruzzaman, Mohammad; Mahadeva, Suresha K.; Khondoker, Abu Hasan; Kim, Jaehwan

    2012-04-01

    This paper investigates the feasibility of conductometric glucose biosensor based on glucose oxidase (GOx) immobilized TiO2-cellulose hybrid nanocomposite. TiO2 nanoparticles were blended with cellulose solution prepared by dissolving cotton pulp with lithium chloride/N, N-dimethylacetamide solvent to fabricate TiO2-cellulose hybrid nanocomposite. The enzyme (GOx) was immobilized into this hybrid material by physical adsorption method. The successful immobilization of GOx into TiO2-cellulose hybrid nanocomposite via covalent bonding between TiO2 and GOx was confirmed by X-ray photoelectron analysis. The linear response of our propose glucose biosensor is obtained in the range of 1-10mM with correlation coefficient of 0.93. Our study demonstrates TiO2-cellulose hybrid material as a potential candidate for an inexpensive, flexible and disposable glucose biosensor.

  8. Finite-dimensional linear algebra

    CERN Document Server

    Gockenbach, Mark S

    2010-01-01

    Some Problems Posed on Vector SpacesLinear equationsBest approximationDiagonalizationSummaryFields and Vector SpacesFields Vector spaces Subspaces Linear combinations and spanning sets Linear independence Basis and dimension Properties of bases Polynomial interpolation and the Lagrange basis Continuous piecewise polynomial functionsLinear OperatorsLinear operatorsMore properties of linear operatorsIsomorphic vector spaces Linear operator equations Existence and uniqueness of solutions The fundamental theorem; inverse operatorsGaussian elimination Newton's method Linear ordinary differential eq

  9. Design of Magnetic Flux Feedback Controller in Hybrid Suspension System

    Directory of Open Access Journals (Sweden)

    Wenqing Zhang

    2013-01-01

    Full Text Available Hybrid suspension system with permanent magnet and electromagnet consumes little power consumption and can realize larger suspension gap. But realizing stable suspension of hybrid magnet is a tricky problem in the suspension control sphere. Considering from this point, we take magnetic flux signal as a state variable and put this signal back to suspension control system. So we can get the hybrid suspension mathematical model based on magnetic flux signal feedback. By application of MIMO feedback linearization theory, we can further realize linearization of the hybrid suspension system. And then proportion, integral, differentiation, magnetic flux density B (PIDB controller is designed. Some hybrid suspension experiments have been done on CMS04 magnetic suspension bogie of National University of Defense Technology (NUDT in China. The experiments denote that the new hybrid suspension control algorithm based on magnetic flux signal feedback designed in this paper has more advantages than traditional position-current double cascade control algorithm. Obviously, the robustness and stability of hybrid suspension system have been enhanced.

  10. Topics in computational linear optimization

    DEFF Research Database (Denmark)

    Hultberg, Tim Helge

    2000-01-01

    . Linear optimization problems covers both linear programming problems, which are polynomially solvable, and mixed integer linear programming problems, which belong to the class of NP-hard problems. The three main reasons for the practical succes of linear optimization are: wide applicability, availabilty...... of high quality solvers and the use of algebraic modelling systems to handle the communication between the modeller and the solver. This dissertation features four topics in computational linear optimization: A) automatic reformulation of mixed 0/1 linear programs, B) direct solution of sparse unsymmetric...... systems of linear equations, C) reduction of linear programs and D) integration of algebraic modelling of linear optimization problems in C++. Each of these topics is treated in a separate paper included in this dissertation. The efficiency of solving mixed 0-1 linear programs by linear programming based...

  11. Linearizing nonlinear optics

    CERN Document Server

    Schmidt, Bruno E; Ernotte, Guilmot; Clerici, Matteo; Morandotti, Roberto; Ibrahim, Heide; Legare, Francois

    2016-01-01

    In the framework of linear optics, light fields do not interact with each other in a medium. Yet, when their field amplitude becomes comparable to the electron binding energies of matter, the nonlinear motion of these electrons emits new dipole radiation whose amplitude, frequency and phase differ from the incoming fields. Such high fields are typically achieved with ultra-short, femtosecond (1fs = 10-15 sec.) laser pulses containing very broad frequency spectra. Here, the matter not only couples incoming and outgoing fields but also causes different spectral components to interact and mix through a convolution process. In this contribution, we describe how frequency domain nonlinear optics overcomes the shortcomings arising from this convolution in conventional time domain nonlinear optics1. We generate light fields with previously inaccessible properties because the uncontrolled coupling of amplitudes and phases is turned off. For example, arbitrary phase functions are transferred linearly to the second har...

  12. Extended linear chain compounds

    CERN Document Server

    Linear chain substances span a large cross section of contemporary chemistry ranging from covalent polymers, to organic charge transfer com­ plexes to nonstoichiometric transition metal coordination complexes. Their commonality, which coalesced intense interest in the theoretical and exper­ imental solid state physics/chemistry communities, was based on the obser­ vation that these inorganic and organic polymeric substrates exhibit striking metal-like electrical and optical properties. Exploitation and extension of these systems has led to the systematic study of both the chemistry and physics of highly and poorly conducting linear chain substances. To gain a salient understanding of these complex materials rich in anomalous aniso­ tropic electrical, optical, magnetic, and mechanical properties, the conver­ gence of diverse skills and talents was required. The constructive blending of traditionally segregated disciplines such as synthetic and physical organic, inorganic, and polymer chemistry, crystallog...

  13. Linear recursive distributed representations.

    Science.gov (United States)

    Voegtlin, Thomas; Dominey, Peter F

    2005-09-01

    Connectionist networks have been criticized for their inability to represent complex structures with systematicity. That is, while they can be trained to represent and manipulate complex objects made of several constituents, they generally fail to generalize to novel combinations of the same constituents. This paper presents a modification of Pollack's Recursive Auto-Associative Memory (RAAM), that addresses this criticism. The network uses linear units and is trained with Oja's rule, in which it generalizes PCA to tree-structured data. Learned representations may be linearly combined, in order to represent new complex structures. This results in unprecedented generalization capabilities. Capacity is orders of magnitude higher than that of a RAAM trained with back-propagation. Moreover, regularities of the training set are preserved in the new formed objects. The formation of new structures displays developmental effects similar to those observed in children when learning to generalize about the argument structure of verbs.

  14. Piecewise Linear Wilson lines

    CERN Document Server

    Van der Veken, Frederik F

    2014-01-01

    Wilson lines, being comparators that render non-local operator products gauge invariant, are extensively used in QCD calculations, especially in small-$x$ calculations, calculations concerning validation of factorisation schemes and in calculations for constructing or modelling parton density functions. We develop an algorithm to express piecewise path ordered exponentials as path ordered integrals over the separate segments, and apply it on linear segments, reducing the number of diagrams needed to be calculated. We show how different linear path topologies can be related using their colour structure. This framework allows one to easily switch results between different Wilson line structures, which is especially useful when testing different structures against each other, e.g. when checking universality properties of non-perturbative objects.

  15. Scaled Sparse Linear Regression

    CERN Document Server

    Sun, Tingni

    2011-01-01

    Scaled sparse linear regression jointly estimates the regression coefficients and noise level in a linear model. It chooses an equilibrium with a sparse regression method by iteratively estimating the noise level via the mean residual squares and scaling the penalty in proportion to the estimated noise level. The iterative algorithm costs nearly nothing beyond the computation of a path of the sparse regression estimator for penalty levels above a threshold. For the scaled Lasso, the algorithm is a gradient descent in a convex minimization of a penalized joint loss function for the regression coefficients and noise level. Under mild regularity conditions, we prove that the method yields simultaneously an estimator for the noise level and an estimated coefficient vector in the Lasso path satisfying certain oracle inequalities for the estimation of the noise level, prediction, and the estimation of regression coefficients. These oracle inequalities provide sufficient conditions for the consistency and asymptotic...

  16. Mathematical Modeling of Hybrid Electrical Engineering Systems

    Directory of Open Access Journals (Sweden)

    A. A. Lobaty

    2016-01-01

    Full Text Available A large class of systems that have found application in various industries and households, electrified transportation facilities and energy sector has been classified as electrical engineering systems. Their characteristic feature is a combination of continuous and discontinuous modes of operation, which is reflected in the appearance of a relatively new term “hybrid systems”. A wide class of hybrid systems is pulsed DC converters operating in a pulse width modulation, which are non-linear systems with variable structure. Using various methods for linearization it is possible to obtain linear mathematical models that rather accurately simulate behavior of such systems. However, the presence in the mathematical models of exponential nonlinearities creates considerable difficulties in the implementation of digital hardware. The solution can be found while using an approximation of exponential functions by polynomials of the first order, that, however, violates the rigor accordance of the analytical model with characteristics of a real object. There are two practical approaches to synthesize algorithms for control of hybrid systems. The first approach is based on the representation of the whole system by a discrete model which is described by difference equations that makes it possible to synthesize discrete algorithms. The second approach is based on description of the system by differential equations. The equations describe synthesis of continuous algorithms and their further implementation in a digital computer included in the control loop system. The paper considers modeling of a hybrid electrical engineering system using differential equations. Neglecting the pulse duration, it has been proposed to describe behavior of vector components in phase coordinates of the hybrid system by stochastic differential equations containing generally non-linear differentiable random functions. A stochastic vector-matrix equation describing dynamics of the

  17. Linear network theory

    CERN Document Server

    Sander, K F

    1964-01-01

    Linear Network Theory covers the significant algebraic aspect of network theory, with minimal reference to practical circuits. The book begins the presentation of network analysis with the exposition of networks containing resistances only, and follows it up with a discussion of networks involving inductance and capacity by way of the differential equations. Classification and description of certain networks, equivalent networks, filter circuits, and network functions are also covered. Electrical engineers, technicians, electronics engineers, electricians, and students learning the intricacies

  18. Linear abdominal trauma.

    Science.gov (United States)

    Danto, L A; Wolfman, E F

    1976-03-01

    Three cases of blunt abdominal trauma are presented to exemplify the mechanism of trauma and the problems of diagnosis associated with any linear blow to the abdomen. The mechanisms of visceral injury are reviewed, and special attention is directed to the abdominal wall injury that can be present in these patients. This injury has special implications in directing the operative approach and repair. An unusual aortic occlusion is described which is peculiar to this type of injury.

  19. Redesigning linear algebra algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J.J.

    1983-01-01

    Many of the standard algorithms in linear algebra as implemented in FORTRAN do not achieve maximum performance on today's large-scale vector computers. The author examines the problem and constructs alternative formulations of algorithms that do not lose the clarity of the original algorithm or sacrifice the FORTRAN portable environment, but do gain the performance attainable on these supercomputers. The resulting implementation not only performs well on vector computers but also increases performance on conventional sequential computers. 13 references.

  20. Redesigning linear algebra algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Dongarra, J.J.

    1983-01-01

    Many of the standard algorithms in linear algebra as implemented in FORTRAN do not achieve maximum performance on today's large-scale vector computers. In this paper we examine the problem and construct alternative formulations of algorithms that do not lose the clarity of the original algorithm or sacrifice the Fortran portable environment, but do gain the performance attainable on these supercomputers. The resulting implementation not only performs well on vector computers but also increases performance on conventional sequential computers.

  1. Fundamentals of linear algebra

    CERN Document Server

    Dash, Rajani Ballav

    2008-01-01

    FUNDAMENTALS OF LINEAR ALGEBRA is a comprehensive Text Book, which can be used by students and teachers of All Indian Universities. The Text has easy, understandable form and covers all topics of UGC Curriculum. There are lots of worked out examples which helps the students in solving the problems without anybody's help. The Problem sets have been designed keeping in view of the questions asked in different examinations.

  2. Relativistic Linear Restoring Force

    Science.gov (United States)

    Clark, D.; Franklin, J.; Mann, N.

    2012-01-01

    We consider two different forms for a relativistic version of a linear restoring force. The pair comes from taking Hooke's law to be the force appearing on the right-hand side of the relativistic expressions: d"p"/d"t" or d"p"/d["tau"]. Either formulation recovers Hooke's law in the non-relativistic limit. In addition to these two forces, we…

  3. Linear algebraic groups

    CERN Document Server

    Springer, T A

    1998-01-01

    "[The first] ten chapters...are an efficient, accessible, and self-contained introduction to affine algebraic groups over an algebraically closed field. The author includes exercises and the book is certainly usable by graduate students as a text or for self-study...the author [has a] student-friendly style… [The following] seven chapters... would also be a good introduction to rationality issues for algebraic groups. A number of results from the literature…appear for the first time in a text." –Mathematical Reviews (Review of the Second Edition) "This book is a completely new version of the first edition. The aim of the old book was to present the theory of linear algebraic groups over an algebraically closed field. Reading that book, many people entered the research field of linear algebraic groups. The present book has a wider scope. Its aim is to treat the theory of linear algebraic groups over arbitrary fields. Again, the author keeps the treatment of prerequisites self-contained. The material of t...

  4. The International Linear Collider

    CERN Document Server

    Barish, Barry

    2013-01-01

    In this article, we describe the key features of the recently completed technical design for the International Linear Collider (ILC), a 200-500 GeV linear electron-positron collider (expandable to 1 TeV) that is based on 1.3 GHz superconducting radio-frequency (SCRF) technology. The machine parameters and detector characteristics have been chosen to complement the Large Hadron Collider physics, including the discovery of the Higgs boson, and to further exploit this new particle physics energy frontier with a precision instrument. The linear collider design is the result of nearly twenty years of R&D, resulting in a mature conceptual design for the ILC project that reflects an international consensus. We summarize the physics goals and capability of the ILC, the enabling R&D and resulting accelerator design, as well as the concepts for two complementary detectors. The ILC is technically ready to be proposed and built as a next generation lepton collider, perhaps to be built in stages beginning as a Hig...

  5. Linearized Kernel Dictionary Learning

    Science.gov (United States)

    Golts, Alona; Elad, Michael

    2016-06-01

    In this paper we present a new approach of incorporating kernels into dictionary learning. The kernel K-SVD algorithm (KKSVD), which has been introduced recently, shows an improvement in classification performance, with relation to its linear counterpart K-SVD. However, this algorithm requires the storage and handling of a very large kernel matrix, which leads to high computational cost, while also limiting its use to setups with small number of training examples. We address these problems by combining two ideas: first we approximate the kernel matrix using a cleverly sampled subset of its columns using the Nystr\\"{o}m method; secondly, as we wish to avoid using this matrix altogether, we decompose it by SVD to form new "virtual samples," on which any linear dictionary learning can be employed. Our method, termed "Linearized Kernel Dictionary Learning" (LKDL) can be seamlessly applied as a pre-processing stage on top of any efficient off-the-shelf dictionary learning scheme, effectively "kernelizing" it. We demonstrate the effectiveness of our method on several tasks of both supervised and unsupervised classification and show the efficiency of the proposed scheme, its easy integration and performance boosting properties.

  6. Cardiac hybrid imaging

    Energy Technology Data Exchange (ETDEWEB)

    Gaemperli, Oliver [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); University Hospital Zurich, Nuclear Cardiology, Cardiovascular Center, Zurich (Switzerland); Kaufmann, Philipp A. [University Hospital Zurich, Cardiac Imaging, Zurich (Switzerland); Alkadhi, Hatem [University Hospital Zurich, Institute of Diagnostic and Interventional Radiology, Zurich (Switzerland)

    2014-05-15

    Hybrid cardiac single photon emission computed tomography (SPECT)/CT imaging allows combined assessment of anatomical and functional aspects of cardiac disease. In coronary artery disease (CAD), hybrid SPECT/CT imaging allows detection of coronary artery stenosis and myocardial perfusion abnormalities. The clinical value of hybrid imaging has been documented in several subsets of patients. In selected groups of patients, hybrid imaging improves the diagnostic accuracy to detect CAD compared to the single imaging techniques. Additionally, this approach facilitates functional interrogation of coronary stenoses and guidance with regard to revascularization procedures. Moreover, the anatomical information obtained from CT coronary angiography or coronary artery calcium scores (CACS) adds prognostic information over perfusion data from SPECT. The use of cardiac hybrid imaging has been favoured by the dissemination of dedicated hybrid systems and the release of dedicated image fusion software, which allow simple patient throughput for hybrid SPECT/CT studies. Further technological improvements such as more efficient detector technology to allow for low-radiation protocols, ultra-fast image acquisition and improved low-noise image reconstruction algorithms will be instrumental to further promote hybrid SPECT/CT in research and clinical practice. (orig.)

  7. Hybrid intelligent engineering systems

    CERN Document Server

    Jain, L C; Adelaide, Australia University of

    1997-01-01

    This book on hybrid intelligent engineering systems is unique, in the sense that it presents the integration of expert systems, neural networks, fuzzy systems, genetic algorithms, and chaos engineering. It shows that these new techniques enhance the capabilities of one another. A number of hybrid systems for solving engineering problems are presented.

  8. A Hybrid Imagination

    DEFF Research Database (Denmark)

    Jamison, Andrew; Christensen, Steen Hyldgaard; Botin, Lars

    contexts, or sites, for mixing scientific knowledge and technical skills from different fields and social domains into new combinations, thus fostering what the authors term a “hybrid imagination”. Such a hybrid imagination is especially important today, as a way to counter the competitive and commercial...

  9. Hybrid trajectory spaces

    NARCIS (Netherlands)

    Collins, P.J.

    2005-01-01

    In this paper, we present a general framework for describing and studying hybrid systems. We represent the trajectories of the system as functions on a hybrid time domain, and the system itself by its trajectory space, which is the set of all possible trajectories. The trajectory space is given a na

  10. Editorial: Hybrid Systems

    DEFF Research Database (Denmark)

    Olderog, Ernst-Rüdiger; Ravn, Anders Peter

    2007-01-01

    An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005.......An introduction to three papers in a special issue on Hybrid Systems. These paper were first presented at an IFIP WG 2.2 meeting in Skagen 2005....

  11. Enhanced performance hybrid-arq

    KAUST Repository

    Fareed, Muhammad Mehboob

    2016-06-16

    Apparatuses, computer readable media, and methods are provided for enhancing hybrid automatic repeat request (ARQ) performance. In an example method, a communication device transmits a first element of a vector, where the vector is selected using the information bits to be transmitted as an index in a code book. In some embodiments, this code book is constructed using Linear Constellation Precoding (LCP). If a NACK is received, the communication device transmits a second element of the vector. The process of transmitting elements of the vector continues until an ACK is received or the maximum number of transmission attempts is reached. If an ACK is received, the communication device transmits a first element of another vector of the code book that encodes a second set of information bits. This procedure may continue until all information bits have been transmitted successfully.

  12. Hybrid reactors. [Fuel cycle

    Energy Technology Data Exchange (ETDEWEB)

    Moir, R.W.

    1980-09-09

    The rationale for hybrid fusion-fission reactors is the production of fissile fuel for fission reactors. A new class of reactor, the fission-suppressed hybrid promises unusually good safety features as well as the ability to support 25 light-water reactors of the same nuclear power rating, or even more high-conversion-ratio reactors such as the heavy-water type. One 4000-MW nuclear hybrid can produce 7200 kg of /sup 233/U per year. To obtain good economics, injector efficiency times plasma gain (eta/sub i/Q) should be greater than 2, the wall load should be greater than 1 MW.m/sup -2/, and the hybrid should cost less than 6 times the cost of a light-water reactor. Introduction rates for the fission-suppressed hybrid are usually rapid.

  13. Hybrid propulsion technology program

    Science.gov (United States)

    1990-01-01

    Technology was identified which will enable application of hybrid propulsion to manned and unmanned space launch vehicles. Two design concepts are proposed. The first is a hybrid propulsion system using the classical method of regression (classical hybrid) resulting from the flow of oxidizer across a fuel grain surface. The second system uses a self-sustaining gas generator (gas generator hybrid) to produce a fuel rich exhaust that was mixed with oxidizer in a separate combustor. Both systems offer cost and reliability improvement over the existing solid rocket booster and proposed liquid boosters. The designs were evaluated using life cycle cost and reliability. The program consisted of: (1) identification and evaluation of candidate oxidizers and fuels; (2) preliminary evaluation of booster design concepts; (3) preparation of a detailed point design including life cycle costs and reliability analyses; (4) identification of those hybrid specific technologies needing improvement; and (5) preperation of a technology acquisition plan and large scale demonstration plan.

  14. Differential Equations with Linear Algebra

    CERN Document Server

    Boelkins, Matthew R; Potter, Merle C

    2009-01-01

    Linearity plays a critical role in the study of elementary differential equations; linear differential equations, especially systems thereof, demonstrate a fundamental application of linear algebra. In Differential Equations with Linear Algebra, we explore this interplay between linear algebra and differential equations and examine introductory and important ideas in each, usually through the lens of important problems that involve differential equations. Written at a sophomore level, the text is accessible to students who have completed multivariable calculus. With a systems-first approach, t

  15. Matlab linear algebra

    CERN Document Server

    Lopez, Cesar

    2014-01-01

    MATLAB is a high-level language and environment for numerical computation, visualization, and programming. Using MATLAB, you can analyze data, develop algorithms, and create models and applications. The language, tools, and built-in math functions enable you to explore multiple approaches and reach a solution faster than with spreadsheets or traditional programming languages, such as C/C++ or Java. MATLAB Linear Algebra introduces you to the MATLAB language with practical hands-on instructions and results, allowing you to quickly achieve your goals. In addition to giving an introduction to

  16. Linear right ideal nearrings

    Directory of Open Access Journals (Sweden)

    Kenneth D. Magill

    2001-01-01

    Full Text Available We determine, up to isomorphism, all those topological nearrings n whose additive groups are the n-dimensional Euclidean groups, n>1, and which contain n one-dimensional linear subspaces {Ji}i=1n which are also right ideals of the nearring satisfying several additional properties. Specifically, for each w∈n, we require that there exist wi∈Ji, 1≤i≤n, such that w=w1+w2+⋯+wn and multiplication on the left of w yields the same result as multiplication by the same element on the left of wn. That is, vw=vwn for each v∈n.

  17. Optical linear algebra

    Energy Technology Data Exchange (ETDEWEB)

    Casasent, D.; Ghosh, A.

    1983-01-01

    Many of the linear algebra operations and algorithms possible on optical matrix-vector processors are reviewed. Emphasis is given to the use of direct solutions and their realization on systolic optical processors. As an example, implicit and explicit solutions to partial differential equations are considered. The matrix-decomposition required is found to be the major operation recommended for optical realization. The pipelining and flow of data and operations are noted to be key issues in the realization of any algorithm on an optical systolic array processor. A realization of the direct solution by householder qr decomposition is provided as a specific case study. 19 references.

  18. Estimation of the hybrid lens parameters through rigid gas permeable lens fitting

    OpenAIRE

    Hasani, Mohammadali; Hashemi, Hassan; Jafarzadehpur, Ebrahim; Yekta, Abbas Ali; Dadbin, Nooshin; khabazkhoob, Mehdi

    2016-01-01

    Purpose To estimate the fitting parameters of the hybrid contact lens in patients with corneal ectasia using the rigid gas permeable (RGP) lens. Methods Thirty-four eyes with corneal ectasia were evaluated in this study. The patients were examined once with the RGP lens and once with the hybrid contact lens. The relationship between the base curvature of the RGP and the vault of the hybrid lens and the correlation between their powers were analyzed. Results We found a linear relationship betw...

  19. An algorithm for earthwork allocation considering non-linear factors

    Institute of Scientific and Technical Information of China (English)

    WANG Ren-chao; LIU Jin-fei

    2008-01-01

    For solving the optimization model of earthwork allocation considering non-linear factors, a hybrid al-gorithm combined with the ant algorithm (AA) and particle swarm optimization (PSO) is proposed in this pa-per. Then the proposed method and the LP method are used respectively in solving a linear allocation model of a high rockfill dam project. Results obtained by these two methods are compared each other. It can be conclu-ded that the solution got by the proposed method is extremely approximate to the analytic solution of LP method. The superiority of the proposed method over the LP method in solving a non-linear allocation model is illustrated by a non-linear case. Moreover, further researches on improvement of the algorithm and the allocation model are addressed.

  20. Change-Of-Bases Abstractions for Non-Linear Systems

    CERN Document Server

    Sankaranarayanan, Sriram

    2012-01-01

    We present abstraction techniques that transform a given non-linear dynamical system into a linear system or an algebraic system described by polynomials of bounded degree, such that, invariant properties of the resulting abstraction can be used to infer invariants for the original system. The abstraction techniques rely on a change-of-basis transformation that associates each state variable of the abstract system with a function involving the state variables of the original system. We present conditions under which a given change of basis transformation for a non-linear system can define an abstraction. Furthermore, the techniques developed here apply to continuous systems defined by Ordinary Differential Equations (ODEs), discrete systems defined by transition systems and hybrid systems that combine continuous as well as discrete subsystems. The techniques presented here allow us to discover, given a non-linear system, if a change of bases transformation involving degree-bounded polynomials yielding an alge...