STEPS: a grid search methodology for optimized peptide identification filtering of MS/MS database search results.

Science.gov (United States)

Piehowski, Paul D; Petyuk, Vladislav A; Sandoval, John D; Burnum, Kristin E; Kiebel, Gary R; Monroe, Matthew E; Anderson, Gordon A; Camp, David G; Smith, Richard D

2013-03-01

For bottom-up proteomics, there are wide variety of database-searching algorithms in use for matching peptide sequences to tandem MS spectra. Likewise, there are numerous strategies being employed to produce a confident list of peptide identifications from the different search algorithm outputs. Here we introduce a grid-search approach for determining optimal database filtering criteria in shotgun proteomics data analyses that is easily adaptable to any search. Systematic Trial and Error Parameter Selection--referred to as STEPS--utilizes user-defined parameter ranges to test a wide array of parameter combinations to arrive at an optimal "parameter set" for data filtering, thus maximizing confident identifications. The benefits of this approach in terms of numbers of true-positive identifications are demonstrated using datasets derived from immunoaffinity-depleted blood serum and a bacterial cell lysate, two common proteomics sample types. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Immunosuppressant therapeutic drug monitoring by LC-MS/MS: workflow optimization through automated processing of whole blood samples.

Science.gov (United States)

Marinova, Mariela; Artusi, Carlo; Brugnolo, Laura; Antonelli, Giorgia; Zaninotto, Martina; Plebani, Mario

2013-11-01

Although, due to its high specificity and sensitivity, LC-MS/MS is an efficient technique for the routine determination of immunosuppressants in whole blood, it involves time-consuming manual sample preparation. The aim of the present study was therefore to develop an automated sample-preparation protocol for the quantification of sirolimus, everolimus and tacrolimus by LC-MS/MS using a liquid handling platform. Six-level commercially available blood calibrators were used for assay development, while four quality control materials and three blood samples from patients under immunosuppressant treatment were employed for the evaluation of imprecision. Barcode reading, sample re-suspension, transfer of whole blood samples into 96-well plates, addition of internal standard solution, mixing, and protein precipitation were performed with a liquid handling platform. After plate filtration, the deproteinised supernatants were submitted for SPE on-line. The only manual steps in the entire process were de-capping of the tubes, and transfer of the well plates to the HPLC autosampler. Calibration curves were linear throughout the selected ranges. The imprecision and accuracy data for all analytes were highly satisfactory. The agreement between the results obtained with manual and those obtained with automated sample preparation was optimal (n=390, r=0.96). In daily routine (100 patient samples) the typical overall total turnaround time was less than 6h. Our findings indicate that the proposed analytical system is suitable for routine analysis, since it is straightforward and precise. Furthermore, it incurs less manual workload and less risk of error in the quantification of whole blood immunosuppressant concentrations than conventional methods. © 2013.

Biosorption optimization of lead(II), cadmium(II) and copper(II) using response surface methodology and applicability in isotherms and thermodynamics modeling

International Nuclear Information System (INIS)

Singh, Rajesh; Chadetrik, Rout; Kumar, Rajender; Bishnoi, Kiran; Bhatia, Divya; Kumar, Anil; Bishnoi, Narsi R.; Singh, Namita

2010-01-01

The present study was carried out to optimize the various environmental conditions for biosorption of Pb(II), Cd(II) and Cu(II) by investigating as a function of the initial metal ion concentration, temperature, biosorbent loading and pH using Trichoderma viride as adsorbent. Biosorption of ions from aqueous solution was optimized in a batch system using response surface methodology. The values of R 2 0.9716, 0.9699 and 0.9982 for Pb(II), Cd(II) and Cu(II) ions, respectively, indicated the validity of the model. The thermodynamic properties ΔG o , ΔH o , ΔE o and ΔS o by the metal ions for biosorption were analyzed using the equilibrium constant value obtained from experimental data at different temperatures. The results showed that biosorption of Pb(II) ions by T. viride adsorbent is more endothermic and spontaneous. The study was attempted to offer a better understating of representative biosorption isotherms and thermodynamics with special focuses on binding mechanism for biosorption using the FTIR spectroscopy.

Biosorption optimization of lead(II), cadmium(II) and copper(II) using response surface methodology and applicability in isotherms and thermodynamics modeling

Energy Technology Data Exchange (ETDEWEB)

Singh, Rajesh; Chadetrik, Rout; Kumar, Rajender; Bishnoi, Kiran; Bhatia, Divya; Kumar, Anil [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India); Bishnoi, Narsi R., E-mail: nrbishnoi@gmail.com [Department of Environmental Science and Engineering, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India); Singh, Namita [Department of Bio and Nanotechnology, Guru Jambheshwar University of Science and Technology, Hisar 125001, Haryana (India)

2010-02-15

The present study was carried out to optimize the various environmental conditions for biosorption of Pb(II), Cd(II) and Cu(II) by investigating as a function of the initial metal ion concentration, temperature, biosorbent loading and pH using Trichoderma viride as adsorbent. Biosorption of ions from aqueous solution was optimized in a batch system using response surface methodology. The values of R{sup 2} 0.9716, 0.9699 and 0.9982 for Pb(II), Cd(II) and Cu(II) ions, respectively, indicated the validity of the model. The thermodynamic properties {Delta}G{sup o}, {Delta}H{sup o}, {Delta}E{sup o} and {Delta}S{sup o} by the metal ions for biosorption were analyzed using the equilibrium constant value obtained from experimental data at different temperatures. The results showed that biosorption of Pb(II) ions by T. viride adsorbent is more endothermic and spontaneous. The study was attempted to offer a better understating of representative biosorption isotherms and thermodynamics with special focuses on binding mechanism for biosorption using the FTIR spectroscopy.

Supercritical CO₂assisted extraction and LC-MS identification of picroside I and picroside II from Picrorhiza kurroa.

Science.gov (United States)

Patil, Ajit A; Sachin, Bhusari S; Shinde, Devanand B; Wakte, Pravin S

2013-02-01

Picroside I and picroside II have been studied intensively because of their pharmacological actions and clinical applications. Numerous methods have been reported for extracting picroside I and picroside II from Picrorrhiza. kurroa rhizomes. This is the first report of picroside I and picroside II extraction using the supercritical carbon dioxide assisted extraction technique. To develop supercritical carbon dioxide assisted extraction and LC-MS identification of picroside I and picroside II from the Picrorrhiza kurroa Royle rhizomes. Surface response methodology based on 3³ fractional factorial design was used to extract picroside I and picroside II from P. kurroa rhizomes. The effects of various process factors, namely temperature (40-80°C), pressure (25-35 MPa) and co-solvent (methanol) concentration (0-10% v/v) on extraction yield of the two compounds were evaluated. The picroside I and picroside II contents were determined using validated LC-MS methodology. The maximum yield of picroside I (32.502 ± 1.131 mg/g) and picroside II (9.717 ± 0.382 mg/g) was obtained at the 10% v/v co-solvent concentration, 40°C temperature and 30 MPa pressure. The conventional Soxhlet assisted methanol extract of P. kurroa powder resulted in 36.743 ± 1.75 and 11.251 ± 0.54 mg/g yield of picroside I and picroside II, respectively. Variation of concentration and extraction time showed a significant effect on the picroside I and picroside II yield. Supercritical carbon dioxide assisted extraction using methanol as a co-solvent is an efficient and environmentally sustainable method for extracting picroside I and picroside II from P. kurroa rhizomes. Copyright © 2012 John Wiley & Sons, Ltd.

Development and Validation of a Novel LC-MS/MS Opioid Confirmation Assay: Evaluation of β-glucuronidase Enzymes and Sample Cleanup Methods.

Science.gov (United States)

Yang, He S; Wu, Alan H B; Lynch, Kara L

2016-06-01

With the rise in the use and misuse of prescription opioids, there is an increasing need for the confirmed identification of opioid analgesics in toxicology laboratories. The goals of this study were to (i) systematically evaluate the hydrolysis efficiency of four β-glucuronidase enzymes under optimized condition; (ii) evaluate compound recovery, matrix effects and precision of three protein precipitation plates and (iii) develop and validate a qualitative liquid-chromatography mass spectrometry (LC-MS/MS) assay to identify 13 opioids in urine. A recombinant β-glucuronidase exhibited the best overall hydrolysis efficiency for seven opioid glucuronide conjugates compared with β-glucuronidase from red abalone, Escherichia coli and Patella vulgata One of the protein precipitation plates tested exhibited overall better recovery of the opioids and lower ion suppression compared with the other two plates. An ESI positive mode LC-MS/MS assay for qualitative opioid analysis was developed and validated. Linearity, LOD, precision, matrix effect, recovery, carryover and interference of the method were evaluated. Sixty-two patient samples were analyzed by both a legacy GC-MS opioid method and the LC-MS/MS method, and 22 samples were analyzed by the LC-MS/MS and an LC-MS/MS reference method. The results of the comparisons showed good concordance. Overall, we described an efficient sample preparation procedure for a sensitive qualitative opioid confirmation assay in urine. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Biosorption of Cd(II), Ni(II) and Pb(II) from aqueous solution by dried biomass of aspergillus niger: application of response surface methodology to the optimization of process parameters

Energy Technology Data Exchange (ETDEWEB)

Amini, Malihe; Younesi, Habibollah [Department of Environmental Science, Faculty of Natural Resources and Marine Sciences, Tarbiat Modares University, Noor (Iran)

2009-10-15

In this study, the biosorption of Cd(II), Ni(II) and Pb(II) on Aspergillus niger in a batch system was investigated, and optimal condition determined by means of central composite design (CCD) under response surface methodology (RSM). Biomass inactivated by heat and pretreated by alkali solution was used in the determination of optimal conditions. The effect of initial solution pH, biomass dose and initial ion concentration on the removal efficiency of metal ions by A. niger was optimized using a design of experiment (DOE) method. Experimental results indicated that the optimal conditions for biosorption were 5.22 g/L, 89.93 mg/L and 6.01 for biomass dose, initial ion concentration and solution pH, respectively. Enhancement of metal biosorption capacity of the dried biomass by pretreatment with sodium hydroxide was observed. Maximal removal efficiencies for Cd(II), Ni(III) and Pb(II) ions of 98, 80 and 99% were achieved, respectively. The biosorption capacity of A. niger biomass obtained for Cd(II), Ni(II) and Pb(II) ions was 2.2, 1.6 and 4.7 mg/g, respectively. According to these observations the fungal biomass of A. niger is a suitable biosorbent for the removal of heavy metals from aqueous solutions. Multiple response optimization was applied to the experimental data to discover the optimal conditions for a set of responses, simultaneously, by using a desirability function. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

Stepped MS(All) Relied Transition (SMART): An approach to rapidly determine optimal multiple reaction monitoring mass spectrometry parameters for small molecules.

Science.gov (United States)

Ye, Hui; Zhu, Lin; Wang, Lin; Liu, Huiying; Zhang, Jun; Wu, Mengqiu; Wang, Guangji; Hao, Haiping

2016-02-11

Multiple reaction monitoring (MRM) is a universal approach for quantitative analysis because of its high specificity and sensitivity. Nevertheless, optimization of MRM parameters remains as a time and labor-intensive task particularly in multiplexed quantitative analysis of small molecules in complex mixtures. In this study, we have developed an approach named Stepped MS(All) Relied Transition (SMART) to predict the optimal MRM parameters of small molecules. SMART requires firstly a rapid and high-throughput analysis of samples using a Stepped MS(All) technique (sMS(All)) on a Q-TOF, which consists of serial MS(All) events acquired from low CE to gradually stepped-up CE values in a cycle. The optimal CE values can then be determined by comparing the extracted ion chromatograms for the ion pairs of interest among serial scans. The SMART-predicted parameters were found to agree well with the parameters optimized on a triple quadrupole from the same vendor using a mixture of standards. The parameters optimized on a triple quadrupole from a different vendor was also employed for comparison, and found to be linearly correlated with the SMART-predicted parameters, suggesting the potential applications of the SMART approach among different instrumental platforms. This approach was further validated by applying to simultaneous quantification of 31 herbal components in the plasma of rats treated with a herbal prescription. Because the sMS(All) acquisition can be accomplished in a single run for multiple components independent of standards, the SMART approach are expected to find its wide application in the multiplexed quantitative analysis of complex mixtures. Copyright © 2015 Elsevier B.V. All rights reserved.

Atmospheric pressure photoionization for enhanced compatibility in on-line micellar electrokinetic chromatography-mass spectrometry

NARCIS (Netherlands)

Mol, Roelof; De Jong, Gerhardus J.; Somsen, Govert W.

2005-01-01

Atmospheric pressure photoionization (APPI) is presented as a novel means for the combination of micellar electrokinetic chromatography (MEKC) and mass spectrometry (MS). The on-line coupling is achieved using an adapted sheath flow interface installed on an orthogonal APPI source. Acetone or

Enhanced MALDI-TOF MS Analysis of Phosphopeptides Using an Optimized DHAP/DAHC Matrix

Science.gov (United States)

Hou, Junjie; Xie, Zhensheng; Xue, Peng; Cui, Ziyou; Chen, Xiulan; Li, Jing; Cai, Tanxi; Wu, Peng; Yang, Fuquan

2010-01-01

Selecting an appropriate matrix solution is one of the most effective means of increasing the ionization efficiency of phosphopeptides in matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS). In this study, we systematically assessed matrix combinations of 2, 6-dihydroxyacetophenone (DHAP) and diammonium hydrogen citrate (DAHC), and demonstrated that the low ratio DHAP/DAHC matrix was more effective in enhancing the ionization of phosphopeptides. Low femtomole level of phosphopeptides from the tryptic digests of α-casein and β-casein was readily detected by MALDI-TOF-MS in both positive and negative ion mode without desalination or phosphopeptide enrichment. Compared with the DHB/PA matrix, the optimized DHAP/DAHC matrix yielded superior sample homogeneity and higher phosphopeptide measurement sensitivity, particularly when multiple phosphorylated peptides were assessed. Finally, the DHAP/DAHC matrix was applied to identify phosphorylation sites from α-casein and β-casein and to characterize two phosphorylation sites from the human histone H1 treated with Cyclin-Dependent Kinase-1 (CDK1) by MALDI-TOF/TOF MS. PMID:20339515

Enhanced MALDI-TOF MS Analysis of Phosphopeptides Using an Optimized DHAP/DAHC Matrix

Directory of Open Access Journals (Sweden)

Junjie Hou

2010-01-01

Full Text Available Selecting an appropriate matrix solution is one of the most effective means of increasing the ionization efficiency of phosphopeptides in matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS. In this study, we systematically assessed matrix combinations of 2, 6-dihydroxyacetophenone (DHAP and diammonium hydrogen citrate (DAHC, and demonstrated that the low ratio DHAP/DAHC matrix was more effective in enhancing the ionization of phosphopeptides. Low femtomole level of phosphopeptides from the tryptic digests of α-casein and β-casein was readily detected by MALDI-TOF-MS in both positive and negative ion mode without desalination or phosphopeptide enrichment. Compared with the DHB/PA matrix, the optimized DHAP/DAHC matrix yielded superior sample homogeneity and higher phosphopeptide measurement sensitivity, particularly when multiple phosphorylated peptides were assessed. Finally, the DHAP/DAHC matrix was applied to identify phosphorylation sites from α-casein and β-casein and to characterize two phosphorylation sites from the human histone H1 treated with Cyclin-Dependent Kinase-1 (CDK1 by MALDI-TOF/TOF MS.

Laser Welding Process Parameters Optimization Using Variable-Fidelity Metamodel and NSGA-II

Directory of Open Access Journals (Sweden)

Wang Chaochao

2017-01-01

Full Text Available An optimization methodology based on variable-fidelity (VF metamodels and nondominated sorting genetic algorithm II (NSGA-II for laser bead-on-plate welding of stainless steel 316L is presented. The relationships between input process parameters (laser power, welding speed and laser focal position and output responses (weld width and weld depth are constructed by VF metamodels. In VF metamodels, the information from two levels fidelity models are integrated, in which the low-fidelity model (LF is finite element simulation model that is used to capture the general trend of the metamodels, and high-fidelity (HF model which from physical experiments is used to ensure the accuracy of metamodels. The accuracy of the VF metamodel is verified by actual experiments. To slove the optimization problem, NSGA-II is used to search for multi-objective Pareto optimal solutions. The results of verification experiments show that the obtained optimal parameters are effective and reliable.

Development and Optimization of an UPLC-QTOF-MS/MS Method Based on an In-Source Collision Induced Dissociation Approach for Comprehensive Discrimination of Chlorogenic Acids Isomers from Momordica Plant Species

Directory of Open Access Journals (Sweden)

N. E. Madala

2014-01-01

Full Text Available Chlorogenic acids (CGA have been profiled in the leaves of Momordica balsamina, Momordica charantia, and Momordica foetida. All three species were found to contain the trans and cis isomers of 4-acyl para-coumaroylquinic acid (pCoQA, caffeoylquinic acid (CQA, and feruloylquinic acid (FQA. To the best of our knowledge, this is the first report of pCoQA and FQA and their cis isomers in these Momordica species. These profiles were obtained by a newly developed UPLC-qTOF-MS method based on the in-source collision induced dissociation (ISCID method optimized to mimic the MS2 and MS3 fragmentation of an ion trap-based MS. The presence of the cis isomers is believed to be due to high UV exposure of these plants. Furthermore, the absence of the 3-acyl and 5-acyl CGA molecules points to a metabolic mark that is unusual and represents a very interesting biochemical phenotype of these species. Our optimized ISCID method was also shown to be able to distinguish between the geometrical isomers of all three forms of CGA, a phenomenon previously deemed impossible with other common mass spectrometry systems used for CGA analyses.

Harnessing electro driven separation technique for the separation of selected agrochemicals

International Nuclear Information System (INIS)

Wan Aini Wan Ibrahim; Alam, S.M. Monjurul; Azli Sulaiman

2008-01-01

Electro driven separation techniques offer a different approach to the analysis of complex mixtures than do traditional pressure-driven chromatographic system; it may rely on electrophoresis, the transport of charged species through a medium by an applied field or may rely on electro driven mobile phase to provide a true chromatographic separation. In the current work the potential of an electro driven separation technique viz. Micellar electrokinetic chromatography (MEKC), is harnessed for the separation of selected agrochemicals (organophosphorus pesticides, OPPs) widely used in the agriculture sector in Malaysia. The current study compares the use of MEKC in normal mode (NM) and reverse mode (RM) for the separation of the selected OPPS. This study also highlights the difference in separations produced by performing separations in normal mode-MEKC (NM-MEKC) and reverse mode-MEKC (RM-MEKC) for the selected OPPs. In RM-MEKC, separation is conducted at acidic pH (pH 2.5 in the current work) where the electro osmotic flow (EOF) is weak whereas in NM-MEKC, the separation is carried out under basic pH (9.3 in this work) where the EOF is strong. A reverse migration order of the OPPs was observed under RM-MEKC. Separation under NM-MEKC was found to be superior to those of RM- MEKC. A comparison is also made between separations performed under sweeping-NM-MEKC and sweeping-RM-MEKC. In sweeping, the OPPs are prepared in the same background solution (BGS) minus the micelles and is adjusted to the same conductivity as the BGS. The study showed that NM-MEKC is more sensitive than RM-MEKC but sweeping-RM-MEKC is superior to sweeping-NM-MEKC. However, sweeping-RM-MEKC only separates two of the OPPs in a single run whereas sweeping-NM-MEKC separates four OPPs in a single run. The better choice of separation mode would be sweeping-NM- MEKC for more OPPs separation in a single run. (author)

Optimization of Ultrasound-Assisted Extraction, HPLC and UHPLC-ESI-Q-TOF-MS/MS Analysis of Main Macamides and Macaenes from Maca (Cultivars of Lepidium meyenii Walp

Directory of Open Access Journals (Sweden)

Shu-Xiao Chen

2017-12-01

Full Text Available Ultrasound-assisted extraction (UAE, using petroleum ether as the solvent, was systematically applied to extract main macamides and macaenes from Maca hypocotyls. Extraction yield was related with four variables, including ratio of solution to solid, extraction temperature, extraction time, and extraction power. On the basis of response surface methodology (RSM, the optimal conditions were determined to be the ratio of solution to solid as 10:1 (mL/g, the extraction temperature of 40 °C, the extraction time of 30 min, and the extraction power of 200 W. Based on the optimal extraction method of UAE, the total contents of ten main macamides and two main macaenes of Maca cultivated in twenty different areas of Tibet were analyzed by HPLC and UHPLC-ESI-Q-TOF-MS/MS. This study indicated that UAE was able to effectively extract macamides alkaloids from Maca hypocotyls. Quantitative analysis showed that geographical origins, not ecotypes, played a more important role on the accumulation of active macamides in Maca.

Optimization of Ultrasound-Assisted Extraction, HPLC and UHPLC-ESI-Q-TOF-MS/MS Analysis of Main Macamides and Macaenes from Maca (Cultivars of Lepidium meyenii Walp).

Science.gov (United States)

Chen, Shu-Xiao; Li, Ke-Ke; Pubu, Duoji; Jiang, Si-Ping; Chen, Bin; Chen, Li-Rong; Yang, Zhen; Ma, Chao; Gong, Xiao-Jie

2017-12-10

Ultrasound-assisted extraction (UAE), using petroleum ether as the solvent, was systematically applied to extract main macamides and macaenes from Maca hypocotyls. Extraction yield was related with four variables, including ratio of solution to solid, extraction temperature, extraction time, and extraction power. On the basis of response surface methodology (RSM), the optimal conditions were determined to be the ratio of solution to solid as 10:1 (mL/g), the extraction temperature of 40 °C, the extraction time of 30 min, and the extraction power of 200 W. Based on the optimal extraction method of UAE, the total contents of ten main macamides and two main macaenes of Maca cultivated in twenty different areas of Tibet were analyzed by HPLC and UHPLC-ESI-Q-TOF-MS/MS. This study indicated that UAE was able to effectively extract macamides alkaloids from Maca hypocotyls. Quantitative analysis showed that geographical origins, not ecotypes, played a more important role on the accumulation of active macamides in Maca.

Optimization of analytical and pre-analytical conditions for MALDI-TOF-MS human urine protein profiles.

Science.gov (United States)

Calvano, C D; Aresta, A; Iacovone, M; De Benedetto, G E; Zambonin, C G; Battaglia, M; Ditonno, P; Rutigliano, M; Bettocchi, C

2010-03-11

Protein analysis in biological fluids, such as urine, by means of mass spectrometry (MS) still suffers for insufficient standardization in protocols for sample collection, storage and preparation. In this work, the influence of these variables on healthy donors human urine protein profiling performed by matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS) was studied. A screening of various urine sample pre-treatment procedures and different sample deposition approaches on the MALDI target was performed. The influence of urine samples storage time and temperature on spectral profiles was evaluated by means of principal component analysis (PCA). The whole optimized procedure was eventually applied to the MALDI-TOF-MS analysis of human urine samples taken from prostate cancer patients. The best results in terms of detected ions number and abundance in the MS spectra were obtained by using home-made microcolumns packed with hydrophilic-lipophilic balance (HLB) resin as sample pre-treatment method; this procedure was also less expensive and suitable for high throughput analyses. Afterwards, the spin coating approach for sample deposition on the MALDI target plate was optimized, obtaining homogenous and reproducible spots. Then, PCA indicated that low storage temperatures of acidified and centrifuged samples, together with short handling time, allowed to obtain reproducible profiles without artifacts contribution due to experimental conditions. Finally, interesting differences were found by comparing the MALDI-TOF-MS protein profiles of pooled urine samples of healthy donors and prostate cancer patients. The results showed that analytical and pre-analytical variables are crucial for the success of urine analysis, to obtain meaningful and reproducible data, even if the intra-patient variability is very difficult to avoid. It has been proven how pooled urine samples can be an interesting way to make easier the comparison between

Rapid and simple determination of polyphyllin I, II, VI, and VII in different harvest times of cultivated Paris polyphylla Smith var. yunnanensis (Franch.) Hand.-Mazz by UPLC-MS/MS and FT-IR.

Science.gov (United States)

Wu, Zhe; Zhang, Ji; Xu, Furong; Wang, Yuanzhong; Zhang, Jinyu

2017-01-01

Paris Polyphylla Smith var. yunnanensis (Franch.) Hand.-Mazz ("Dian Chonglou" in Chinese) is a famous herbal medicine in China, which is usually well known for activities of anti-cancer, hemolysis, and cytotoxicity. In this study, Fourier transform infrared (FT-IR) spectroscopy coupled with principal component analysis (PCA) and partial least-squares regression (PLSR) was applied to discriminate samples of P. polyphylla var. yunnanensis harvested in different years and determine the content of polyphyllin I, II, VI, and VII in P. polyphylla var. yunnanensis. Meanwhile, ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was used to study the dynamic changes of P. polyphylla var. yunnanensis harvested in different years (4, 5, 7, 8, 9, 12, and 13 years old). According to the UPLC-MS/MS result, the optimum harvest time of P. polyphylla var. yunnanensis is 8 years, due to the highest yield of four active components. By the PCA model, P. polyphylla var. yunnanensis could be exactly discriminated, except that two 8-year-old samples were misclassified as 9-year-old samples. For the prediction of polyphyllin I, II, VI, and VII, the quantitative results are satisfactory, with a high value for the determination coefficient (R 2 ) and low values for the root-mean-square error of estimation (RMSEE), root-mean-square error of cross-validation (RMSECV), and root-mean-square error of prediction (RMSEP). In conclusion, FT-IR combined with chemometrics is a promising method to accurately discriminate samples of P. polyphylla var. yunnanensis harvested in different years and determine the content of polyphyllin I, II, VI, and VII in P. polyphylla var. yunnanensis.

Application of micellar electrokinetic capillary chromatography for routine analysis of different materials

Directory of Open Access Journals (Sweden)

Injac Rade

2008-01-01

Full Text Available Micellar electrokinetic capillary chromatography (MEKC has become a popular mode among the several capillary electro-migration techniques. Most drug analysis can be performed by using MEKC because of its wide applicability. Separation of very complex mixtures, determination of drugs in the biological materials, etc., can be successfully achieved by MEKC. This review surveys typical applications of MEKC analysis. Recent advances in MEKC, especially with solid-phase extraction and large-volume sample stacking, are described. Modes of electrokinetic chromatography including MEKC, a separation theory of MEKC, environmental friendly analysis, and selectivity manipulation in MEKC are also briefly mentioned.

BEAM OPTIMIZATION STUDY FOR AN X-RAY FEL OSCILLATOR AT THE LCLS-II

Energy Technology Data Exchange (ETDEWEB)

Qin, Weilun; Huang, S.; Liu, K.X.; Huang, Z; Ding, Y.; Maxwell, T.J.; Kim, K.-J.

2016-06-01

The 4 GeV LCLS-II superconducting linac with high repetition beam rate enables the possibility to drive an X-Ray FEL oscillator at harmonic frequencies *. Compared to the regular LCLS-II machine setup, the oscillator mode requires a much longer bunch length with a relatively lower current. Also a flat longitudinal phase space distribution is critical to maintain the FEL gain since the X-ray cavity has extremely narrow bandwidth. In this paper, we study the longitudinal phase space optimization including shaping the initial beam from the injector and optimizing the bunch compressor and dechirper parameters. We obtain a bunch with a flat energy chirp over 400 fs in the core part with current above 100 A. The optimization was based on LiTrack and Elegant simulations using LCLS-II beam parameters.

Towards Optimal Diagnosis of Type II Germ Cell Tumors

NARCIS (Netherlands)

J.A. Stoop (Hans)

2011-01-01

textabstractThe aim of the work described in this thesis is to improve the understanding of the pathobiology of testicular cancer (type II Germ Cell Tumors) to create possibilities for optimalization of diagnosis for this type of malignancy in routine pathology laboratories. The different studies

MsLDR-creator: a web service to design msLDR assays.

Science.gov (United States)

Bormann, Felix; Dahl, Andreas; Sers, Christine

2012-03-01

MsLDR-creator is a free web service to design assays for the new DNA methylation detection method msLDR. The service provides the user with all necessary information about the oligonucleotides required for the measurement of a given CpG within a sequence of interest. The parameters are calculated by the nearest neighbour approach to achieve optimal behaviour during the experimental procedure. In addition, to guarantee a good start using msLDR, further information, like protocols and hints and tricks, are provided.

Analytical Method Details (MS): SE57_MS01 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available TQD, UPLC (Waters) UPLC-QTOF-MS ESI N.A. All the solutions of authentic....1% formic acid), with a 2.5 min cycle in the isocratic mode. The ionized authentic compounds were detected ... optimal CV and CE were determined automatically for 497 of these compounds using the software QuanOptimize

Controlling the structure of sequence-defined poly(phosphodiester)s for optimal MS/MS reading of digital information.

Science.gov (United States)

Amalian, J-A; Al Ouahabi, A; Cavallo, G; König, N F; Poyer, S; Lutz, J-F; Charles, L

2017-11-01

Digital polymers are monodisperse chains with a controlled sequence of co-monomers, defined as letters of an alphabet, and are used to store information at the molecular level. Reading such messages is hence a sequencing task that can be efficiently achieved by tandem mass spectrometry. To improve their readability, structure of sequence-controlled synthetic polymers can be optimized, based on considerations regarding their fragmentation behavior. This strategy is described here for poly(phosphodiester)s, which were synthesized as monodisperse chains with more than 100 units but exhibited extremely complex dissociation spectra. In these polymers, two repeating units that differ by a simple H/CH 3 variation were defined as the 0 and 1 bit of the ASCII code and spaced by a phosphate moiety. They were readily ionized in negative ion mode electrospray but dissociated via cleavage at all phosphate bonds upon collisional activation. Although allowing a complete sequence coverage of digital poly(phosphodiester)s, this fragmentation behavior was not efficient for macromolecules with more than 50 co-monomers, and data interpretation was very tedious. The structure of these polymers was then modified by introducing alkoxyamine linkages at appropriate location throughout the chain. A first design consisted of placing these low dissociation energy bonds between each monomeric bit: while cleavage of this sole bond greatly simplified MS/MS spectra, efficient sequencing was limited to chains with up to about 50 units. In contrast, introduction of alkoxyamine bonds between each byte (i.e. a set of eight co-monomers) was a more successful strategy. Long messages (so far, up to 8 bytes) could be read in MS 3 experiments, where single-byte containing fragments released during the first activation stage were further dissociated for sequencing. The whole sequence of such byte-truncated poly(phosphodiester)s could be easily re-constructed based on a mass tagging system which permits

Optimal recombination in genetic algorithms for combinatorial optimization problems: Part II

Directory of Open Access Journals (Sweden)

Eremeev Anton V.

2014-01-01

Full Text Available This paper surveys results on complexity of the optimal recombination problem (ORP, which consists in finding the best possible offspring as a result of a recombination operator in a genetic algorithm, given two parent solutions. In Part II, we consider the computational complexity of ORPs arising in genetic algorithms for problems on permutations: the Travelling Salesman Problem, the Shortest Hamilton Path Problem and the Makespan Minimization on Single Machine and some other related problems. The analysis indicates that the corresponding ORPs are NP-hard, but solvable by faster algorithms, compared to the problems they are derived from.

Optimal Timing of Heart Transplant After HeartMate II Left Ventricular Assist Device Implantation.

Science.gov (United States)

Steffen, Robert J; Blackstone, Eugene H; Smedira, Nicholas G; Soltesz, Edward G; Hoercher, Katherine J; Thuita, Lucy; Starling, Randall C; Mountis, Maria; Moazami, Nader

2017-11-01

Optimal timing of heart transplantation in patients supported with second-generation left ventricular assist devices (LVADs) is unknown. Despite this, patients with LVADs continue to receive priority on the heart transplant waiting list. Our objective was to determine the optimal timing of transplantation for patients bridged with continuous-flow LVADs. A total of 301 HeartMate II LVADs (Thoratec Corp, Pleasanton, CA) were implanted in 285 patients from October 2004 to June 2013, and 86 patients underwent transplantation through the end of follow-up. Optimal transplantation timing was the product of surviving on LVAD support and surviving transplant. Three-year survival after both HeartMate II implantation and heart transplantation was unchanged when transplantation occurred within 9 months of implantation. Survival decreased as the duration of support exceeded this. Preoperative risk factors for death on HeartMate II support were prior valve operation, prior coronary artery bypass grafting, low albumin, low glomerular filtration rate, higher mean arterial pressure, hypertension, and earlier date of implant. Survival for patients without these risk factors was lowest when transplant was performed within 3 months but was relatively constant with increased duration of support. Longer duration of support was associated with poorer survival for patients with many of these risk factors. Device reimplantation, intracranial hemorrhage, and postimplant dialysis during HeartMate II support were associated with decreased survival. Survival of patients supported by the HeartMate II is affected by preoperative comorbidities and postoperative complications. Transplantation before complications is imperative in optimizing survival. Copyright © 2017 The Society of Thoracic Surgeons. Published by Elsevier Inc. All rights reserved.

ToF-SIMS Parallel Imaging MS/MS of Lipid Species in Thin Tissue Sections.

Science.gov (United States)

Bruinen, Anne Lisa; Fisher, Gregory L; Heeren, Ron M A

2017-01-01

Unambiguous identification of detected species is essential in complex biomedical samples. To date, there are not many mass spectrometry imaging techniques that can provide both high spatial resolution and identification capabilities. A new and patented imaging tandem mass spectrometer, exploiting the unique characteristics of the nanoTOF II (Physical Electronics, USA) TOF-SIMS TRIFT instrument, was developed to address this.Tandem mass spectrometry is based on the selection of precursor ions from the full secondary ion spectrum (MS 1 ), followed by energetic activation and fragmentation, and collection of the fragment ions to obtain a tandem MS spectrum (MS 2 ). The PHI NanoTOF II mass spectrometer is equipped with a high-energy collision induced dissociation (CID) fragmentation cell as well as a second time-of-flight analyzer developed for simultaneous ToF-SIMS and tandem MS imaging experiments.We describe here the results of a ToF-SIMS imaging experiment on a thin tissue section of an infected zebrafish as a model organism for tuberculosis. The focus is on the obtained ion distribution plot of a fatty acid as well as its identification by tandem mass spectrometry.

What Is in Your Wallet? Quantitation of Drugs of Abuse on Paper Currency with a Rapid LC-MS/MS Method

Science.gov (United States)

Parker, Patrick D.; Beers, Brandon; Vergne, Matthew J.

2017-01-01

Laboratory experiments were developed to introduce students to the quantitation of drugs of abuse by high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS). Undergraduate students were introduced to internal standard quantitation and the LC-MS/MS method optimization for cocaine. Cocaine extracted from paper currency was…

Optimization and Comparison of ESI and APCI LC-MS/MS Methods: A Case Study of Irgarol 1051, Diuron, and their Degradation Products in Environmental Samples

Science.gov (United States)

Maragou, Niki C.; Thomaidis, Nikolaos S.; Koupparis, Michael A.

2011-10-01

A systematic and detailed optimization strategy for the development of atmospheric pressure ionization (API) LC-MS/MS methods for the determination of Irgarol 1051, Diuron, and their degradation products (M1, DCPMU, DCPU, and DCA) in water, sediment, and mussel is described. Experimental design was applied for the optimization of the ion sources parameters. Comparison of ESI and APCI was performed in positive- and negative-ion mode, and the effect of the mobile phase on ionization was studied for both techniques. Special attention was drawn to the ionization of DCA, which presents particular difficulty in API techniques. Satisfactory ionization of this small molecule is achieved only with ESI positive-ion mode using acetonitrile in the mobile phase; the instrumental detection limit is 0.11 ng/mL. Signal suppression was qualitatively estimated by using purified and non-purified samples. The sample preparation for sediments and mussels is direct and simple, comprising only solvent extraction. Mean recoveries ranged from 71% to 110%, and the corresponding (%) RSDs ranged between 4.1 and 14%. The method limits of detection ranged between 0.6 and 3.5 ng/g for sediment and mussel and from 1.3 to 1.8 ng/L for sea water. The method was applied to sea water, marine sediment, and mussels, which were obtained from marinas in Attiki, Greece. Ion ratio confirmation was used for the identification of the compounds.

The optimization and validation of the Biotyper MALDI-TOF MS database for the identification of Gram-positive anaerobic cocci

NARCIS (Netherlands)

Veloo, A. C. M.; de Vries, E D; Jean-Pierre, H.; Justesen, U. S.; Morris, T.; Urban, E.; Wybo, I.; van Winkelhoff, A. J.

OBJECTIVES: Gram-positive anaerobic cocci (GPAC) account for 24-31% of the anaerobic bacteria isolated from human clinical specimens. At present GPAC are underrepresented in the Biotyper MALDI-TOF MS database. Profiles of new species have yet to be added. We present the optimization of the MALDI-TOF

Simultaneous and rapid determination of caffeine and taurine in energy drinks by MEKC in a short capillary with dual contactless conductivity/photometry detection.

Science.gov (United States)

Vochyánová, Blanka; Opekar, František; Tůma, Petr

2014-06-01

A method has been developed for the simultaneous determination of taurine and caffeine using a laboratory-made instrument enabling separation analysis in a short 10.5 cm capillary. The substances are detected using a contactless conductometry/ultraviolet (UV) photometry detector that enables recording both signals at one place in the capillary. The separation of caffeine and taurine was performed using the MEKC technique in a BGE with the composition 40 mM CHES, 15 mM NaOH, and 50 mM SDS, pH 9.36. Under these conditions, the migration time of caffeine is 43 s and of taurine 60 s; LOD for caffeine is 4 mg/L using photometric detection and LOD for taurine is 24 mg/L using contactless conductometric detection. The standard addition method was used for determination in Red Bull energy drink of caffeine 317 mg/L and taurine 3860 mg/L; the contents in Kamikaze drink were 468 mg/L caffeine and 4110 mg/L taurine. The determined values are in good agreement with the declared contents of these substances. RSD does not exceed 3%. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Chiral speciation and determination of selenomethionine enantiomers in selenized yeast by ligand-exchange micellar electrokinetic capillary chromatography after solid phase extraction.

Science.gov (United States)

Duan, Jiankun; He, Man; Hu, Bin

2012-12-14

A new phenylalanine derivative (L-N-(2-hydroxy-propyl)-phenylalanine, L-HP-Phe) was synthesized and its chelate with Cu(II) (Cu(II)-(L-HP-Phe)(2)) was used as the chiral selector for the ligand-exchange (LE) chiral separation of D,L-selenomethionine (SeMet) in selenized yeast samples by micelle electrokinetic capillary chromatography (MEKC). In order to improve the sensitivity of MEKC-UV, two-step preconcentration strategy was employed, off-line solid phase extraction (SPE) and on-line large volume sample stacking (LVSS). D,L-SeMet was first retained on the Cu(II) loaded mesoporous TiO(2), then eluted by 0.1 mL of 5 mol L(-1) ammonia, and finally introduced for MEKC-UV analysis by LVSS injection after evaporation of NH(3). With the enrichment factors of 1400 and 1378, the LODs of 0.44 and 0.60 ng mL(-1) for L-SeMet and D-SeMet was obtained, respectively. The developed method was applied to the analysis of D,L-SeMet in a certified reference material of SELM-1 and a commercial nutrition yeast, and the results showed that most of SeMet in the SELM-1 selenized yeast was l isomer and the recovery for L and D isomers in the spiked commercial nutrition yeast was 96.3% and 103%, respectively. This method is featured with low running cost, high sensitivity and selectivity, and exhibits application potential in chiral analysis of seleno amino acids in real world samples. Copyright © 2012 Elsevier B.V. All rights reserved.

Multi-objective Optimization of Pulsed Gas Metal Arc Welding Process Using Neuro NSGA-II

Science.gov (United States)

Pal, Kamal; Pal, Surjya K.

2018-05-01

Weld quality is a critical issue in fabrication industries where products are custom-designed. Multi-objective optimization results number of solutions in the pareto-optimal front. Mathematical regression model based optimization methods are often found to be inadequate for highly non-linear arc welding processes. Thus, various global evolutionary approaches like artificial neural network, genetic algorithm (GA) have been developed. The present work attempts with elitist non-dominated sorting GA (NSGA-II) for optimization of pulsed gas metal arc welding process using back propagation neural network (BPNN) based weld quality feature models. The primary objective to maintain butt joint weld quality is the maximization of tensile strength with minimum plate distortion. BPNN has been used to compute the fitness of each solution after adequate training, whereas NSGA-II algorithm generates the optimum solutions for two conflicting objectives. Welding experiments have been conducted on low carbon steel using response surface methodology. The pareto-optimal front with three ranked solutions after 20th generations was considered as the best without further improvement. The joint strength as well as transverse shrinkage was found to be drastically improved over the design of experimental results as per validated pareto-optimal solutions obtained.

[Orthogonal design method to optimize rehabilitation prescription of pulsed electric field at Jiaji (EX-B 2) points for spinal cord injury].

Science.gov (United States)

Zhang, Lifeng; Zhang, Hui; Wang, Lin; Liu, Yanyan; Sun, Xianyue; Li, Lingyan; Hou, Jing

2015-01-01

By using orthogonal design method to optimnize prescription of pulsed electric field at Jiaji (EX- B 2) points for spinal cord injury (SCI). Fifty six patients of SCI were selected, in which 36 cases were divided into orthogonal design trial and 20 cases were into clinical verification. With 36 patients who received orthogonal design trial, Frankel grading scale was used as observation index to screen optimal prescription of pulsed electric field. Pulse frequency (factor A) included low frequency (factor A(I), 10(2) Hz). moderate frequency (factor A(II), 10(4) Hz) and high frequency (factor A(III), 10(3) Hz); pulse amplitude (factor B) included 0-30 V (factor B ), 0-60 V (factor B(II)) and 0-90 V (factor B(III)); pulse width (factor C) included 0.1 ms (factor C(I)). 0.6 ms (factor C(II)) and 0.9 ms (factor C(III)); acupuncture time (factor D) included one month (DI), three months (D(II)) and five months (D(III)). Twenty patients were used for clinical efficacy observation and the effects of screened optimal pre scription of pulsed electric field at Jiaji (EX-B 2) points combined with regular rehabilitation training on spasm se- verity, score of sensory and motor functions, Barthel index and Frankel score were observed. (1) As results of orthogonal design trial, the optimal prescription was A(III) B(III), C(I), D(III), which were high frequency (10(3) Hz), 0-90 V of pulse amplitude, 0.4 ms of pulse width and 5 months of treatment time. (2) As results of 20 patient clinical verification, Ashworth score, tendon reflex and clonus were all significantly improved (Ppulsed electric field at Jiaji (EX-B 2) points for spinal cord injury is high frequency (10& Hz), 0-90 V of pulse amplitude, 0.4 ms of pulse width and 5 months of treatment time. The optimal prescription of pulsed electric field at Jiaji (EX-B 2) points combined with regular rehabilitation could obviously improve spasm severity, enhance senso- ry and motor functions, and ameliorate activity of daily life and

Development and Validation of a Fast Procedure To Analyze Amoxicillin in River Waters by Direct-Injection LC-MS/MS

OpenAIRE

Vera Homem; Arminda Alves; Lúcia Silveira Santos

2014-01-01

A laboratory application with a strong component in analytical chemistry was designed for undergraduate students, in order to introduce a current problem in the environmental science field, the water contamination by antibiotics. Therefore, a simple and rapid method based on direct injection and high performance liquid chromatography-tandem mass spectrometry (LC-MS/MS) was developed and optimized for the determination of amoxicillin in river water. Students learned the main optimization steps...

Optimizing beam transport in rapidly compressing beams on the neutralized drift compression experiment – II

Directory of Open Access Journals (Sweden)

Anton D. Stepanov

2018-03-01

Full Text Available The Neutralized Drift Compression Experiment-II (NDCX-II is an induction linac that generates intense pulses of 1.2 MeV helium ions for heating matter to extreme conditions. Here, we present recent results on optimizing beam transport. The NDCX-II beamline includes a 1-m-long drift section downstream of the last transport solenoid, which is filled with charge-neutralizing plasma that enables rapid longitudinal compression of an intense ion beam against space-charge forces. The transport section on NDCX-II consists of 28 solenoids. Finding optimal field settings for a group of solenoids requires knowledge of the envelope parameters of the beam. Imaging the beam on the scintillator gives the radius of the beam, but the envelope angle is not measured directly. We demonstrate how the parameters of the beam envelope (radius, envelop angle, and emittance can be reconstructed from a series of images taken by varying the B-field strengths of a solenoid upstream of the scintillator. We use this technique to evaluate emittance at several points in the NDCX-II beamline and for optimizing the trajectory of the beam at the entry of the plasma-filled drift section. Keywords: Charged-particle beams, Induction accelerators, Beam dynamics, Beam emittance, Ion beam diagnostics, PACS Codes: 41.75.-i, 41.85.Ja, 52.59.Sa, 52.59.Wd, 29.27.Eg

Application of CE-ICP-MS and CE-ESI-MS/MS for identification of Zn-binding ligands in Goji berries extracts.

Science.gov (United States)

Ruzik, Lena; Kwiatkowski, Piotr

2018-06-01

The identification of groups of ligands binding metals is a crucial issue for the better understanding of their bioaccessibility. In the current study, we have intended an approach for identification of Zn-binding ligands based on using capillary electrophoresis combined with inductively coupled plasma mass spectrometry (CE-ICP-MS) and tandem electrospray ionization mass spectrometry (CE-ESI-MS/MS). The approach, which featured the use of the coupling of capillary electrophoresis with inductively coupled plasma mass spectrometry allows to separate and observe zinc ions present in complexes with respect to their size and charge and to identify nine compounds with zinc isotopic profile. CE-ICP-MS provides us with information about presence of zinc species and elemental information about zinc distribution. CE-ESI-MS/MS provide us with information about the most favorable Zn binding ligands: amino acids, flavonols, stilbenoids, fenolic acids and carotenoids. The presented work is the continuation of previous studies based on using LC-ESI-MS/MS, though, now we presented a new solutions with the possibility of changing detectors without changing the separation techniques, what is important without re-optimizing the method. The new presented method allows to identify the zinc-binding ligands in shorter time. Copyright © 2018 Elsevier B.V. All rights reserved.

Optimization of colorimetric DET technique for the in situ, two-dimensional measurement of iron(II) distributions in sediment porewaters

DEFF Research Database (Denmark)

Bennett, William W.; Teasdale, Peter R.; Welsh, David T.

2012-01-01

The recently developed colorimetric diffusive equilibration in thin films (DET) technique for the in situ, high-resolution measurement of iron(II) in marine sediments is optimized to allow measurement of the higher iron concentrations typical of freshwater sediment porewaters. Computer imaging...... the sensitivity of the assay as required; by processing the image with different color channel filters, the sensitivity of the assay can be optimized for lower concentrations (up to 100 μmol L -1) or higher concentrations (up to 2000 μmol L -1) of iron(II), depending on the specific site characteristics......(II) in sediment porewaters. The detection limit of the optimized technique was 4.1 ± 0.3 μmol L -1 iron(II) and relative standard deviations were less than 6%....

The optimization of phthalate analysis from plastic matrices by using GC/MS related techniques

Science.gov (United States)

Pusfitasari, Eka Dian; Hendarsyah, Hendris; Athaillah, Zatil Afrah

2017-11-01

Indication of malicious acts conducted by food vendors has been reported in many places in Indonesia and has been worrying the population. One of the issues is the indication that frying oil used by the vendors has been added with food packaging plastic to impart more crispy texture of the fried foods. One of the challenges for the monitoring process is to find suitable analytical method to identify this type of food adulteration. Because some food packaging, particularly from polyethylene group, contains plasticizer diethylhexylphthalate (DEHP), we intended to investigate the adulteration by detecting the phthalate compound. In this preliminary study, we focused on the optimization of GC equipment as well as the optimization of plastic extraction process with various types of solvents (hexane, dichloromethane, and acetonitrile) and extraction time (24, 48, and 72 hours). For 72-hour duration, treatment with solvent refreshment was also conducted to minimize solvent saturation effect. Our findings suggested that LOD and LOQ of the GC/MS instrument used for the DEHP analysis were 19.6 ng and 65.5 ng, respectively. In addition, it could be concluded that the process of plastic extraction through sonication for five minutes with n-hexane as a solvent resulted in the optimal value.

Scope Oriented Thermoeconomic analysis of energy systems. Part II: Formation Structure of Optimality for robust design

International Nuclear Information System (INIS)

Piacentino, Antonio; Cardona, Ennio

2010-01-01

This paper represents the Part II of a paper in two parts. In Part I the fundamentals of Scope Oriented Thermoeconomics have been introduced, showing a scarce potential for the cost accounting of existing plants; in this Part II the same concepts are applied to the optimization of a small set of design variables for a vapour compression chiller. The method overcomes the limit of most conventional optimization techniques, which are usually based on hermetic algorithms not enabling the energy analyst to recognize all the margins for improvement. The Scope Oriented Thermoeconomic optimization allows us to disassemble the optimization process, thus recognizing the Formation Structure of Optimality, i.e. the specific influence of any thermodynamic and economic parameter in the path toward the optimal design. Finally, the potential applications of such an in-depth understanding of the inner driving forces of the optimization are discussed in the paper, with a particular focus on the sensitivity analysis to the variation of energy and capital costs and on the actual operation-oriented design.

Sensitive Detection of Organophosphorus Pesticides in Medicinal Plants Using Ultrasound-Assisted Dispersive Liquid-Liquid Microextraction Combined with Sweeping Micellar Electrokinetic Chromatography.

Science.gov (United States)

Wei, Jin-Chao; Hu, Ji; Cao, Ji-Liang; Wan, Jian-Bo; He, Cheng-Wei; Hu, Yuan-Jia; Hu, Hao; Li, Peng

2016-02-03

A simple, rapid, and sensitive method using ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) combined with sweeping micellar electrokinetic chromatography (sweeping-MEKC) has been developed for the determination of nine organophosphorus pesticides (chlorfenvinphos, parathion, quinalphos, fenitrothion, azinphos-ethyl, parathion-methyl, fensulfothion, methidathion, and paraoxon). The important parameters that affect the UA-DLLME and sweeping efficiency were investigated. Under the optimized conditions, the proposed method provided 779.0-6203.5-fold enrichment of the nine pesticides compared to the normal MEKC method. The limits of detection ranged from 0.002 to 0.008 mg kg(-1). The relative standard deviations of the peak area ranged from 1.2 to 6.5%, indicating the good repeatability of the method. Finally, the developed UA-DLLME-sweeping-MEKC method has been successfully applied to the analysis of the investigated pesticides in several medicinal plants, including Lycium chinense, Dioscorea opposite, Codonopsis pilosula, and Panax ginseng, indicating that this method is suitable for the determination of trace pesticide residues in real samples with complex matrices.

Optimizing the structure of Tetracyanoplatinate(II)

DEFF Research Database (Denmark)

Dohn, Asmus Ougaard; Møller, Klaus Braagaard; Sauer, Stephan P. A.

2013-01-01

. For the C-N bond these trends are reversed and an order of magnitude smaller. With respect to the basis set dependence we observed that a triple zeta basis set with polarization functions gives in general sufficiently converged results, but while for the Pt-C bond it is advantageous to include extra diffuse......The geometry of tetracyanoplatinate(II) (TCP) has been optimized with density functional theory (DFT) calculations in order to compare different computational strategies. Two approximate scalar relativistic methods, i.e. the scalar zeroth-order regular approximation (ZORA) and non...... is almost quantitatively reproduced in the ZORA and ECP calculations. In addition, the effect of the exchange-correlation functional and one-electron basis set was studied by employing the two generalized gradient approximation (GGA) functionals, BLYP and PBE, as well as their hybrid version B3LYP and PBE0...

Visualization of Chronic Myocardial Infarction Using the Intravascular Contrast Agent MS-325 (Gadofosveset in Patients

Directory of Open Access Journals (Sweden)

Thomas Thouet

2012-01-01

Full Text Available Aims. The aim of this study was to evaluate the potential of visualizing chronic myocardial infarction in patients using the intravascular CA MS-325 (gadofosveset, EPIX Pharmaceuticals, Mass, USA. Methods. Nine patients were enrolled in a clinical phase II multicenter trial for MRCA and perfusion imaging using MS-325. They had objective evidence of chronic myocardial infarction as visualized by previously performed late gadolinium (Gd enhancement imaging (LGE with a conventional extracellular Gd-DTPA CA (Magnevist, Bayer Healthcare, Germany, 0.2 mmol/kg/body weight serving as reference standard. A prepulse-optimized LGE study was performed immediately and at several time points after injection of MS-325 (0.05 mmol/kg/body weight. The number and localization of segments demonstrating LGE with MS-325 as well as signal intensities were compared with the reference standard (Gd-DTPA. Results. Using MS-325, LGE could be detected at every time point in all 9 patients. The accuracy of LGE with MS-325 as compared to LGE with Gd-DTPA was highest 54±4 minutes after contrast injection, resulting in a sensitivity of 84% with a specificity of 98%. Conclusion. The intravascular CA MS-325 has the potential to visualize chronic myocardial infarction. However, in comparison with Gd-DTPA, the transmural extent and the number of segments are smaller.

Information-dependent acquisition-mediated LC-MS/MS screening procedure with semiquantitative potential.

Science.gov (United States)

Decaestecker, Tineke N; Vande Casteele, Sofie R; Wallemacq, Pierre E; Van Peteghem, Carlos H; Defore, Dieter L; Van Bocxlaer, Jan F

2004-11-01

The development of a LC-MS/MS general unknown screening procedure for toxicologically relevant substances in blood samples by means of information-dependent acquisition on a Q-TOF is reported. IDA is an artificial intelligence-based product ion scan mode providing automatic "on-the-fly" MS to MS/MS switching. By performing information-dependent scanning at two different fragmentation energies, two collision-induced dissociation product ion spectra for each of the detected compounds are generated. As such, information-rich MS/MS spectra are obtained from precursor ions not known beforehand. In addition, limitation of the MS/MS acquisition time to an acceptable minimum resulted in an almost instantaneous switch back to the MS mode. As such, this approach provided MS chromatograms that still could be of use for semiquantitative purposes. Since the switching intensity threshold, unequivocally related to the background noise, proved a critical parameter, the solid-phase extraction procedure, the liquid chromatographic conditions, and the mass spectrometric parameters all were optimized to the advantage of information-dependent acquisition. Finally, the screening procedure we developed was benchmarked, on one hand, qualitatively against the results obtained from traditional GUS approaches in a number of routine toxicological laboratories (20 samples) and, on the other hand, quantitatively with respect to its potential against established LC-MS/MS methods (7 samples). The procedure performed very well from a qualitative point of view; almost all of the drugs detected by the conventional techniques were identified, as well as additional drugs that were not previously reported. The procedure proved well-suited for an initial semiquantitative assessment, as is customary in, for example, forensic toxicology before accurate intoxication levels are determined using targeted analytical analyses.

Analysis of RET promoter CpG island methylation using methylation-specific PCR (MSP), pyrosequencing, and methylation-sensitive high-resolution melting (MS-HRM): impact on stage II colon cancer patient outcome.

Science.gov (United States)

Draht, Muriel X G; Smits, Kim M; Jooste, Valérie; Tournier, Benjamin; Vervoort, Martijn; Ramaekers, Chantal; Chapusot, Caroline; Weijenberg, Matty P; van Engeland, Manon; Melotte, Veerle

2016-01-01

Already since the 1990s, promoter CpG island methylation markers have been considered promising diagnostic, prognostic, and predictive cancer biomarkers. However, so far, only a limited number of DNA methylation markers have been introduced into clinical practice. One reason why the vast majority of methylation markers do not translate into clinical applications is lack of independent validation of methylation markers, often caused by differences in methylation analysis techniques. We recently described RET promoter CpG island methylation as a potential prognostic marker in stage II colorectal cancer (CRC) patients of two independent series. In the current study, we analyzed the RET promoter CpG island methylation of 241 stage II colon cancer patients by direct methylation-specific PCR (MSP), nested-MSP, pyrosequencing, and methylation-sensitive high-resolution melting (MS-HRM). All primers were designed as close as possible to the same genomic region. In order to investigate the effect of different DNA methylation assays on patient outcome, we assessed the clinical sensitivity and specificity as well as the association of RET methylation with overall survival for three and five years of follow-up. Using direct-MSP and nested-MSP, 12.0 % (25/209) and 29.6 % (71/240) of the patients showed RET promoter CpG island methylation. Methylation frequencies detected by pyrosequencing were related to the threshold for positivity that defined RET methylation. Methylation frequencies obtained by pyrosequencing (threshold for positivity at 20 %) and MS-HRM were 13.3 % (32/240) and 13.8 % (33/239), respectively. The pyrosequencing threshold for positivity of 20 % showed the best correlation with MS-HRM and direct-MSP results. Nested-MSP detected RET promoter CpG island methylation in deceased patients with a higher sensitivity (33.1 %) compared to direct-MSP (10.7 %), pyrosequencing (14.4 %), and MS-HRM (15.4 %). While RET methylation frequencies detected by nested

Implementation of strength pareto evolutionary algorithm II in the multiobjective burnable poison placement optimization of KWU pressurized water reactor

International Nuclear Information System (INIS)

Gharari, Rahman; Poursalehi, Navid; Abbasi, Mohmmadreza; Aghale, Mahdi

2016-01-01

In this research, for the first time, a new optimization method, i.e., strength Pareto evolutionary algorithm II (SPEA-II), is developed for the burnable poison placement (BPP) optimization of a nuclear reactor core. In the BPP problem, an optimized placement map of fuel assemblies with burnable poison is searched for a given core loading pattern according to defined objectives. In this work, SPEA-II coupled with a nodal expansion code is used for solving the BPP problem of Kraftwerk Union AG (KWU) pressurized water reactor. Our optimization goal for the BPP is to achieve a greater multiplication factor (K-e-f-f) for gaining possible longer operation cycles along with more flattening of fuel assembly relative power distribution, considering a safety constraint on the radial power peaking factor. For appraising the proposed methodology, the basic approach, i.e., SPEA, is also developed in order to compare obtained results. In general, results reveal the acceptance performance and high strength of SPEA, particularly its new version, i.e., SPEA-II, in achieving a semioptimized loading pattern for the BPP optimization of KWU pressurized water reactor

Implementation of strength pareto evolutionary algorithm II in the multiobjective burnable poison placement optimization of KWU pressurized water reactor

Energy Technology Data Exchange (ETDEWEB)

Gharari, Rahman [Nuclear Science and Technology Research Institute (NSTRI), Tehran (Iran, Islamic Republic of); Poursalehi, Navid; Abbasi, Mohmmadreza; Aghale, Mahdi [Nuclear Engineering Dept, Shahid Beheshti University, Tehran (Iran, Islamic Republic of)

2016-10-15

In this research, for the first time, a new optimization method, i.e., strength Pareto evolutionary algorithm II (SPEA-II), is developed for the burnable poison placement (BPP) optimization of a nuclear reactor core. In the BPP problem, an optimized placement map of fuel assemblies with burnable poison is searched for a given core loading pattern according to defined objectives. In this work, SPEA-II coupled with a nodal expansion code is used for solving the BPP problem of Kraftwerk Union AG (KWU) pressurized water reactor. Our optimization goal for the BPP is to achieve a greater multiplication factor (K-e-f-f) for gaining possible longer operation cycles along with more flattening of fuel assembly relative power distribution, considering a safety constraint on the radial power peaking factor. For appraising the proposed methodology, the basic approach, i.e., SPEA, is also developed in order to compare obtained results. In general, results reveal the acceptance performance and high strength of SPEA, particularly its new version, i.e., SPEA-II, in achieving a semioptimized loading pattern for the BPP optimization of KWU pressurized water reactor.

Thermo-economic and environmental analyses based multi-objective optimization of vapor compression–absorption cascaded refrigeration system using NSGA-II technique

International Nuclear Information System (INIS)

Jain, Vaibhav; Sachdeva, Gulshan; Kachhwaha, Surendra Singh; Patel, Bhavesh

2016-01-01

Highlights: • It addresses multi-objective optimization study on cascaded refrigeration system. • Cascaded system is a promising decarburizing and energy efficient technology. • NSGA-II technique is used for multi-objective optimization. • Total annual product cost and irreversibility rate are simultaneously optimized. - Abstract: Present work optimizes the performance of 170 kW vapor compression–absorption cascaded refrigeration system (VCACRS) based on combined thermodynamic, economic and environmental parameters using Non-dominated Sort Genetic Algorithm-II (NSGA-II) technique. Two objective functions including the total irreversibility rate (as a thermodynamic criterion) and the total product cost (as an economic criterion) of the system are considered simultaneously for multi-objective optimization of VCACRS. The capital and maintenance costs of the system components, the operational cost, and the penalty cost due to CO_2 emission are included in the total product cost of the system. Three optimized systems including a single-objective thermodynamic optimized, a single-objective economic optimized and a multi-objective optimized are analyzed and compared. The results showed that the multi-objective design considers the combined thermodynamic and total product cost criteria better than the two individual single-objective thermodynamic and total product cost optimized designs.

Zwitterion-functionalized polymer microspheres as a sorbent for solid phase extraction of trace levels of V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) prior to their determination by ICP-MS.

Science.gov (United States)

Jia, Xiaoyu; Gong, Dirong; Zhao, Junyi; Ren, Hongyun; Wang, Jiani; Zhang, Xian

2018-03-19

This paper describes the preparation of zwitterion-functionalized polymer microspheres (ZPMs) and their application to simultaneous enrichment of V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) from environmental water samples. The ZPMs were prepared by emulsion copolymerization of ethyl methacrylate, 2-diethylaminoethyl methacrylate and triethylene glycol dimethyl acrylate followed by modification with 1,3-propanesultone. The components were analyzed by elemental analyses as well as Fourier transform infrared spectroscopy, and the structures were characterized by scanning electron microscopy and transmission electron microscopy. The ZPMs were packed into a mini-column for on-line solid-phase extraction (SPE) of the above metal ions. Following extraction with 40 mM NH 4 NO 3 and 0.5 M HNO 3 solution, the ions were quantified by ICP-MS. Under the optimized conditions, the enrichment factors (from a 40 mL sample) are up to 60 for the ions V(V), As(III), Sb(III) and Hg(II), and 55 for Cr(III) and Sn(IV). The detection limits are 1.2, 3.4, 1.0, 3.7, 2.1 and 1.6 ng L -1 for V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II), respectively, and the relative standard deviations (RSDs) are below 5.2%. The feasibility and accuracy of the method were validated by successfully analyzing six certified reference materials as well as lake, well and river waters. Graphical abstract Zwitterion-functionalized polymer microspheres (ZPMs) were prepared and packed into a mini-column for on-line solid-phase extraction (SPE) via pump 1. Then V(V), Cr(III), As(III), Sn(IV), Sb(III) and Hg(II) ions in environmental waters were eluted and submitted to ICP-MS via pump 2.

Identifying inaccuracy of MS Project using system analysis

Science.gov (United States)

Fachrurrazi; Husin, Saiful; Malahayati, Nurul; Irzaidi

2018-05-01

The problem encountered in project owner’s financial accounting report is the difference in total project costs of MS Project to the Indonesian Standard (Standard Indonesia Standard / Cost Estimating Standard Book of Indonesia). It is one of the MS Project problems concerning to its cost accuracy, so cost data cannot be used in an integrated way for all project components. This study focuses on finding the causes of inaccuracy of the MS Projects. The aim of this study, which is operationally, are: (i) identifying cost analysis procedures for both current methods (SNI) and MS Project; (ii) identifying cost bias in each element of the cost analysis procedure; and (iii) analysing the cost differences (cost bias) in each element to identify what the cause of inaccuracies in MS Project toward SNI is. The method in this study is comparing for both the system analysis of MS Project and SNI. The results are: (i) MS Project system in Work of Resources element has limitation for two decimal digits only, have led to its inaccuracy. Where the Work of Resources (referred to as effort) in MS Project represents multiplication between the Quantities of Activities and Requirements of resources in SNI; (ii) MS Project and SNI have differences in the costing methods (the cost estimation methods), in which the SNI uses the Quantity-Based Costing (QBC), meanwhile MS Project uses the Time-Based Costing (TBC). Based on this research, we recommend to the contractors who use SNI should make an adjustment for Work of Resources in MS Project (with correction index) so that it can be used in an integrated way to the project owner’s financial accounting system. Further research will conduct for improvement the MS Project as an integrated tool toward all part of the project participant.

UFLC-ESI-MS/MS analysis of multiple mycotoxins in medicinal and edible Areca catechu.

Science.gov (United States)

Liu, Hongmei; Luo, Jiaoyang; Kong, Weijun; Liu, Qiutao; Hu, Yichen; Yang, Meihua

2016-05-01

A robust, sensitive and reliable ultra fast liquid chromatography combined with electrospray ionization tandem mass spectrometry (UFLC-ESI-MS/MS) was optimized and validated for simultaneous identification and quantification of eleven mycotoxins in medicinal and edible Areca catechu, based on one-step extraction without any further clean-up. Separation and quantification were performed in both positive and negative modes under multiple reaction monitoring (MRM) in a single run with zearalanone (ZAN) as internal standard. The chromatographic conditions and MS/MS parameters were carefully optimized. Matrix-matched calibration was recommended to reduce matrix effects and improve accuracy, showing good linearity within wide concentration ranges. Limits of quantification (LOQ) were lower than 50 μg kg(-1), while limits of detection (LOD) were in the range of 0.1-20 μg kg(-1). The accuracy of the developed method was validated for recoveries, ranging from 85% to 115% with relative standard deviation (RSD) ≤14.87% at low level, from 75% to 119% with RSD ≤ 14.43% at medium level and from 61% to 120% with RSD ≤ 13.18% at high level, respectively. Finally, the developed multi-mycotoxin method was applied for screening of these mycotoxins in 24 commercial samples. Only aflatoxin B2 and zearalenone were found in 2 samples. This is the first report on the application of UFLC-ESI(+/-)-MS/MS for multi-class mycotoxins in A. catechu. The developed method with many advantages of simple pretreatment, rapid determination and high sensitivity is a proposed candidate for large-scale detection and quantification of multiple mycotoxins in other complex matrixes. Copyright © 2016 Elsevier Ltd. All rights reserved.

NSGA-II based optimal control scheme of wind thermal power system for improvement of frequency regulation characteristics

Directory of Open Access Journals (Sweden)

S. Chaine

2015-09-01

Full Text Available This work presents a methodology to optimize the controller parameters of doubly fed induction generator modeled for frequency regulation in interconnected two-area wind power integrated thermal power system. The gains of integral controller of automatic generation control loop and the proportional and derivative controllers of doubly fed induction generator inertial control loop are optimized in a coordinated manner by employing the multi-objective non-dominated sorting genetic algorithm-II. To reduce the numbers of optimization parameters, a sensitivity analysis is done to determine that the above mentioned three controller parameters are the most sensitive among the rest others. Non-dominated sorting genetic algorithm-II has depicted better efficiency of optimization compared to the linear programming, genetic algorithm, particle swarm optimization, and cuckoo search algorithm. The performance of the designed optimal controller exhibits robust performance even with the variation in penetration levels of wind energy, disturbances, parameter and operating conditions in the system.

An improved fast and elitist multi-objective genetic algorithm-ANSGA-II for multi-objective optimization of inverse radiotherapy treatment planning

International Nuclear Information System (INIS)

Cao Ruifen; Li Guoli; Song Gang; Zhao Pan; Lin Hui; Wu Aidong; Huang Chenyu; Wu Yican

2007-01-01

Objective: To provide a fast and effective multi-objective optimization algorithm for inverse radiotherapy treatment planning system. Methods: Non-dominated Sorting Genetic Algorithm-NSGA-II is a representative of multi-objective evolutionary optimization algorithms and excels the others. The paper produces ANSGA-II that makes use of advantage of NSGA-II, and uses adaptive crossover and mutation to improve its flexibility; according the character of inverse radiotherapy treatment planning, the paper uses the pre-known knowledge to generate individuals of every generation in the course of optimization, which enhances the convergent speed and improves efficiency. Results: The example of optimizing average dose of a sheet of CT, including PTV, OAR, NT, proves the algorithm could find satisfied solutions in several minutes. Conclusions: The algorithm could provide clinic inverse radiotherapy treatment planning system with selection of optimization algorithms. (authors)

Matrix Optical Absorption in UV-MALDI MS.

Science.gov (United States)

Robinson, Kenneth N; Steven, Rory T; Bunch, Josephine

2018-03-01

In ultraviolet matrix-assisted laser desorption/ionization mass spectrometry (UV-MALDI MS) matrix compound optical absorption governs the uptake of laser energy, which in turn has a strong influence on experimental results. Despite this, quantitative absorption measurements are lacking for most matrix compounds. Furthermore, despite the use of UV-MALDI MS to detect a vast range of compounds, investigations into the effects of laser energy have been primarily restricted to single classes of analytes. We report the absolute solid state absorption spectra of the matrix compounds α-cyano-4-hydroxycinnamic acid (CHCA), para-nitroaniline (PNA), 2-mercaptobenzothiazole (MBT), 2,5-dihydroxybenzoic acid (2,5-DHB), and 2,4,6-trihydroxyacetophenone (THAP). The desorption/ionization characteristics of these matrix compounds with respect to laser fluence was investigated using mixed systems of matrix with either angiotensin II, PC(34:1) lipid standard, or haloperidol, acting as representatives for typical classes of analyte encountered in UV-MALDI MS. The first absolute solid phase spectra for PNA, MBT, and THAP are reported; additionally, inconsistencies between previously published spectra for CHCA are resolved. In light of these findings, suggestions are made for experimental optimization with regards to matrix and laser wavelength selection. The relationship between matrix optical cross-section and wavelength-dependant threshold fluence, fluence of maximum ion yield, and R, a new descriptor for the change in ion intensity with fluence, are described. A matrix cross-section of 1.3 × 10 -17 cm -2 was identified as a potential minimum for desorption/ionization of analytes. Graphical Abstract ᅟ.

UPLC-MS/MS based diagnostics for epithelial ovarian cancer using fully sialylated C4-binding protein.

Science.gov (United States)

Tanabe, Kazuhiro; Matsuo, Koji; Miyazawa, Masaki; Hayashi, Masaru; Ikeda, Masae; Shida, Masako; Hirasawa, Takeshi; Sho, Ryuichiro; Mikami, Mikio

2018-05-01

Serum levels of fully sialylated C4-binding protein (FS-C4BP) are remarkably elevated in patients with epithelial ovarian cancer (EOC) and can be used as a marker to distinguish ovarian clear cell carcinoma from endometrioma. This study aimed to develop a stable, robust and reliable liquid chromatography-hybrid mass spectrometry (UPLC-MS/MS) based diagnostic method that would generalize FS-C4BP as a clinical EOC biomarker. Glycopeptides derived from 20 μL of trypsin-digested serum glycoprotein were analyzed via UPLC equipped with an electrospray ionization time-of-flight mass spectrometer. This UPLC-MS/MS-based diagnostic method was optimized for FS-C4BP and validated using sera from 119 patients with EOC and 127 women without cancer. A1958 (C4BP peptide with two fully sialylated biantennary glycans) was selected as a marker of FS-C4BP because its level in serum was highest among FS-C4BP family members. Preparation and UPLC-MS/MS were optimized for A1958, and performance and robustness were significantly improved relative to our previous method. An area under the curve analysis of the FS-C4BP index receiver operating characteristic curve revealed that the ratio between A1958 and A1813 (C4BP peptide with two partially sialylated biantennary glycans) reached 85%. A combination of the FS-C4BP index and carbohydrate antigen-125 levels further enhanced the sensitivity and specificity. © 2017 The Authors. Biomedical Chromatography published by John Wiley & Sons Ltd.

Analytical methods for multiresidue determination of sulfonamides and trimethoprim in meat and ground water samples by CE-MS and CE-MS/MS.

Science.gov (United States)

Soto-Chinchilla, Jorge J; García-Campaña, Ana M; Gámiz-Gracia, Laura

2007-11-01

This paper presents two methods based on CZE-MS detection and CZE-MS/MS detection developed for the multiresidue determination of ten sulfonamides (sulfapyridine, sulfadoxin, sulfamethazine, sulfadimethoxine, sulfameter, sulfamerazine, sulfachlorpyridazine, sulfadiazine, sulfamethoxazole, and sulfamethizole) and a potentiator, trimethoprim (TMP), whose contents are regulated by the EU Council Regulation no. 2377/90 in animal edible tissues. Experimental designs were employed to optimize the electrospray conditions. MS/MS experiments using an IT as analyzer operating in multiple reaction monitoring (MRM) mode were carried out to achieve the minimum number of points according to the 2002/657/EC European Decision for unambiguous identification. The proposed procedures have been compared in terms of the performance characteristics and trueness. The limits of detection and quantification were in all cases lower than the maximum residue limits legislated for these compounds and the recoveries were satisfactory, being possible the application for their monitoring in foodstuff of animal origin and in environmental samples, allowing the determination of sulfonamides and TMP residues in meat and in superficial water in the low microg/L range.

UPLC-PDA-ESI-qTOF-MS profiling and potent anti-HSV-II activity of Eucalyptus sideroxylon leaves.

Science.gov (United States)

Okba, Mona M; El Gedaily, Rania A; Ashour, Rehab M

2017-11-15

Eucalyptus is one of the most important and highly exploited genus in family Myrtaceae. An UPLC/PDA/ESI-qTOF-MS method was adopted to identify Eucalyptus sideroxylon Cunn. ex Woolls leaves phytoconstituents. Cytotoxicity of E. sideroxylon leaves phloroglucinol-rich extract (PGRE) on VERO cells was determined. The antiviral effect of PGRE against hepatitis A (HAV), herpes simplex type 1 (HSV-I), herpes simplex type 2 (HSV-II), coxsackie (CoxB4), and adenoviruses was in vitro evaluated using MTT assay (3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyl tetrazolium bromide). UPLC-MS analysis allowed the identification of 70 metabolites including: 26 triterpenes, 13 phloroglucinols, 8 fatty acids, 5 flavonoids, 5 oleuropeic acid glucosides, 3 gallic acid derivatives, and 10 miscellaneous. Twenty four metabolites identified in the leaves of E. sideroxylon and four in the genus Eucalyptus are reported herein for the first time. PGRE was found to be non-cytotoxic; the concentration that reduced the cell viability by 50% (CC 50 ) was 0.808mg/mL. Maximum non-toxic concentration (MNTC) of PGRE on Vero cells was 0.312mg/mL. The best antiviral activity was observed against HSV-II. Its mechanism was through decreasing the viral replication (IC 50 189.36μg/mL, 87.65% inhibition) and attachment on Vero cells (IC 50 199.34μg/mL, 83.13% inhibition) rather than virucidal effect (IC 50 293.1μg/mL, 50.68% inhibition). This study provides a complete map for E. sideroxylon leaves composition. It also suggests the plant as a source of new antiviral agents. Copyright © 2017 Elsevier B.V. All rights reserved.

Ultrafuzziness Optimization Based on Type II Fuzzy Sets for Image Thresholding

Directory of Open Access Journals (Sweden)

Hudan Studiawan

2010-11-01

Full Text Available Image thresholding is one of the processing techniques to provide high quality preprocessed image. Image vagueness and bad illumination are common obstacles yielding in a poor image thresholding output. By assuming image as fuzzy sets, several different fuzzy thresholding techniques have been proposed to remove these obstacles during threshold selection. In this paper, we proposed an algorithm for thresholding image using ultrafuzziness optimization to decrease uncertainty in fuzzy system by common fuzzy sets like type II fuzzy sets. Optimization was conducted by involving ultrafuzziness measurement for background and object fuzzy sets separately. Experimental results demonstrated that the proposed image thresholding method had good performances for images with high vagueness, low level contrast, and grayscale ambiguity.

Multiobjective Optimization for Fixture Locating Layout of Sheet Metal Part Using SVR and NSGA-II

Directory of Open Access Journals (Sweden)

Yuan Yang

2017-01-01

Full Text Available Fixture plays a significant role in determining the sheet metal part (SMP spatial position and restraining its excessive deformation in many manufacturing operations. However, it is still a difficult task to design and optimize SMP fixture locating layout at present because there exist multiple conflicting objectives and excessive computational cost of finite element analysis (FEA during the optimization process. To this end, a new multiobjective optimization method for SMP fixture locating layout is proposed in this paper based on the support vector regression (SVR surrogate model and the elitist nondominated sorting genetic algorithm (NSGA-II. By using ABAQUS™ Python script interface, a parametric FEA model is established. And the fixture locating layout is treated as design variables, while the overall deformation and maximum deformation of SMP under external forces are as the multiple objective functions. First, a limited number of training and testing samples are generated by combining Latin hypercube design (LHD with FEA. Second, two SVR prediction models corresponding to the multiple objectives are established by learning from the limited training samples and are integrated as the multiobjective optimization surrogate model. Third, NSGA-II is applied to determine the Pareto optimal solutions of SMP fixture locating layout. Finally, a multiobjective optimization for fixture locating layout of an aircraft fuselage skin case is conducted to illustrate and verify the proposed method.

Analysis of the constituents in jojoba wax used as a food additive by LC/MS/MS.

Science.gov (United States)

Tada, Atsuko; Jin, Zhe-Long; Sugimoto, Naoki; Sato, Kyoko; Yamazaki, Takeshi; Tanamoto, Kenichi

2005-10-01

Jojoba wax is a natural gum base used as a food additive in Japan, and is obtained from jojoba oil with a characteristically high melting point. Although the constituents of jojoba oil have been reported, the quality of jojoba wax used as a food additive has not yet been clarified. In order to evaluate its quality as a food additive and to obtain basic information useful for setting official standards, we investigated the constituents and their concentrations in jojoba wax. LC/MS analysis of the jojoba wax showed six peaks with [M+H]+ ions in the range from m/z 533.6 to 673.7 at intervals of m/z 28. After isolation of the components of the four main peaks by preparative LC/MS, the fatty acid and long chain alcohol moieties of the wax esters were analyzed by methanolysis and hydrolysis, followed by GC/MS. The results indicated that the main constituents in jojoba wax were various kinds of wax esters, namely eicosenyl octadecenoate (C20:1-C18:1) (1), eicosenyl eicosenoate (C20:1-C20:1) (II), docosenyl eicosenoate (C22:1-C20:1) (III), eicosenyl docosenoate (C20:1-C22:1) (IV) and tetracosenyl eiosenoate (C24:1-C20:1) (V). To confirm and quantify the wax esters in jojoba wax directly, LC/MS/MS analysis was performed. The product ions corresponding to the fatty acid moieties of the wax esters were observed, and by using the product ions derived from the protonated molecular ions of wax esters the fatty acid moieties were identified by MRM analysis. The concentrations of the wax esters I, II and III, in jojoba wax were 5.5, 21.4 and 37.8%, respectively. In summary, we clarified the main constituents of jojoba wax and quantified the molecular species of the wax esters without hydrolysis by monitoring their product ions, using a LC/MS/MS system.

Optimal power flow: a bibliographic survey II. Non-deterministic and hybrid methods

Energy Technology Data Exchange (ETDEWEB)

Frank, Stephen [Colorado School of Mines, Department of Electrical Engineering and Computer Science, Golden, CO (United States); Steponavice, Ingrida [Univ. of Jyvaskyla, Dept. of Mathematical Information Technology, Agora (Finland); Rebennack, Steffen [Colorado School of Mines, Division of Economics and Business, Golden, CO (United States)

2012-09-15

Over the past half-century, optimal power flow (OPF) has become one of the most important and widely studied nonlinear optimization problems. In general, OPF seeks to optimize the operation of electric power generation, transmission, and distribution networks subject to system constraints and control limits. Within this framework, however, there is an extremely wide variety of OPF formulations and solution methods. Moreover, the nature of OPF continues to evolve due to modern electricity markets and renewable resource integration. In this two-part survey, we survey both the classical and recent OPF literature in order to provide a sound context for the state of the art in OPF formulation and solution methods. The survey contributes a comprehensive discussion of specific optimization techniques that have been applied to OPF, with an emphasis on the advantages, disadvantages, and computational characteristics of each. Part I of the survey provides an introduction and surveys the deterministic optimization methods that have been applied to OPF. Part II of the survey (this article) examines the recent trend towards stochastic, or non-deterministic, search techniques and hybrid methods for OPF. (orig.)

User's manual for the BNW-II optimization code for dry/wet-cooled power plants

International Nuclear Information System (INIS)

Braun, D.J.; Bamberger, J.A.; Braun, D.J.; Faletti, D.W.; Wiles, L.E.

1978-05-01

The User's Manual describes how to operate BNW-II, a computer code developed by the Pacific Northwest Laboratory (PNL) as a part of its activities under the Department of Energy (DOE) Dry Cooling Enhancement Program. The computer program offers a comprehensive method of evaluating the cost savings potential of dry/wet-cooled heat rejection systems. Going beyond simple ''figure-of-merit'' cooling tower optimization, this method includes such items as the cost of annual replacement capacity, and the optimum split between plant scale-up and replacement capacity, as well as the purchase and operating costs of all major heat rejection components. Hence the BNW-II code is a useful tool for determining potential cost savings of new dry/wet surfaces, new piping, or other components as part of an optimized system for a dry/wet-cooled plant

Pt(II) and Pd(II) complexes with ibuprofen hydrazide: Characterization, theoretical calculations, antibacterial and antitumor assays and studies of interaction with CT-DNA

Science.gov (United States)

Manzano, Carlos M.; Bergamini, Fernando R. G.; Lustri, Wilton R.; Ruiz, Ana Lúcia T. G.; de Oliveira, Ellen C. S.; Ribeiro, Marcos A.; Formiga, André L. B.; Corbi, Pedro P.

2018-02-01

Palladium(II) and platinum(II) complexes with a hydrazide derivative of ibuprofen (named HIB) were synthesized and characterized by chemical and spectroscopic methods. Elemental and thermogravimetric analyses, as well as ESI-QTOF-MS studies for both complexes, confirmed a 1:2:2 metal/HIB/Cl- molar ratio. The crystal structure of the palladium(II) complex was solved by single crystal X-ray diffractometric analysis, which permitted identifying the coordination formula [PdCl2(HIB)2]. Crystallographic studies also indicate coordination of HIB to the metal by the NH2 group. Nuclear magnetic resonance and infrared spectroscopies reinforced the coordination observed in the crystal structure and suggested that the platinum(II) complex presents similar coordination modes and structure when compared with the Pd(II) complex. The complexes had their structures optimized with the aid of DFT methods. In vitro antiproliferative assays showed that the [PdCl2(HIB)2] complex is active over ovarian cancer cell line OVCAR-03, while biophysical studies indicated its capacity to interact with CT-DNA. The complexes were inactive over Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa bacterial strains.

The optimal control of ITU TRIGA Mark II Reactor

International Nuclear Information System (INIS)

Can, Burhanettin

2008-01-01

In this study, optimal control of ITU TRIGA Mark-II Reactor is discussed. A new controller has been designed for ITU TRIGA Mark-II Reactor. The controller consists of main and auxiliary controllers. The form is based on Pontragyn's Maximum Principle and the latter is based on PID approach. For the desired power program, a cubic function is chosen. Integral Performance Index includes the mean square of error function and the effect of selected period on the power variation. YAVCAN2 Neutronic - Thermal -Hydraulic code is used to solve the equations, namely 11 equations, dealing with neutronic - thermal - hydraulic behavior of the reactor. For the controller design, a new code, KONTCAN, is written. In the application of the code, it is seen that the controller controls the reactor power to follow the desired power program. The overshoot value alters between 100 W and 500 W depending on the selected period. There is no undershoot. The controller rapidly increases reactivity, then decreases, after that increases it until the effect of temperature feedback is compensated. Error function varies between 0-1 kW. (author)

Energy, exergy, economic (3E) analyses and multi-objective optimization of vapor absorption heat transformer using NSGA-II technique

International Nuclear Information System (INIS)

Jain, Vaibhav; Sachdeva, Gulshan

2017-01-01

Highlights: • Study includes energy, exergy and economic analyses of absorption heat transformer. • It addresses multi-objective optimization study using NSGA-II technique. • Total annual cost and total exergy destruction are simultaneously optimized. • Results with multi-objective optimized design are more acceptable than other. - Abstract: Present paper addresses the energy, exergy and economic (3E) analyses of absorption heat transformer (AHT) working with LiBr-H 2 O fluid pair. The heat exchangers namely absorber, condenser, evaporator, generator and solution heat exchanger are designed for the size and cost estimation of AHT. Later, the effect of operating variables is examined on the system performance, size and cost. Simulation studies showed a conflict between thermodynamic and economic performance of the system. The heat exchangers with lower investment cost showed high irreversible losses and vice versa. Thus, the operating variables of systems are determined economically as well as thermodynamically by implementing non-dominated sort genetic algorithm-II (NSGA-II) technique of multi-objective optimization. In present work, if the cost based optimized design is chosen, total exergy destruction is 2.4% higher than its minimum possible value; whereas, if total exergy based optimized design is chosen, total annual cost is 6.1% higher than its minimum possible value. On the other hands, total annual cost and total exergy destruction are only 1.0% and 0.8%, respectively more from their minimum possible values with multi-objective optimized design. Thus, the multi-objective optimized design of the AHT is best outcome than any other single-objective optimized designs.

Characterization of Proteins Present in Isolated Senile Plaques from Alzheimer's Diseased Brains by MALDI-TOF MS with MS/MS.

Science.gov (United States)

Kelley, Andrea R; Perry, George; Bach, Stephan B H

2018-04-18

The increase of insoluble senile plaques in the brain is a primary hallmark of Alzheimer's disease. The usefulness of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with tandem MS for the characterization of senile plaques from AD brains and the relevance of the components identified to furthering AD research using MS is discussed. Thirty-three components were reproducibly observed within tryptic aliquots of senile plaques from two different AD brains after sample preparation optimization. Additionally, this is one of the first accounts of LIFT being utilized for the direct sequencing of peptides from isolated senile plaques. While many of the species observed coisolated within senile plaques have been linked to AD etiology, if only speculatively, this is the first instance that many of them have been demonstrated to be a part of the plaques themselves. This work is the first step in determining the potential roles that the species may have in the aggregation or proliferation of the plaques.

UPLC-MS/MS determination of ptaquiloside and pterosin B in preserved natural water

DEFF Research Database (Denmark)

Clauson-Kaas, Frederik; Hansen, Hans Chr. Bruun; Strobel, Bjarne W.

2016-01-01

and preconcentration of samples with solid phase extraction, before analyte quantification with UPLC-MS/MS. By including gradient elution and optimizing the liquid chromatography mobile phase buffer system, a total run cycle of 5 min was achieved, with method detection limits, including preconcentration, of 8 and 4 ng....../L for ptaquiloside and pterosin B, respectively. The use of loganin as internal standard improved repeatability of the determination of both analytes, though it could not be employed for sample preparation. Buffering raw water samples in situ with ammonium acetate to pH ∼5.5 decisively increased sample integrity...

Preliminary study of urine metabolism in type two diabetic patients based on GC-MS

OpenAIRE

Zhang, Ning; Geng, Fang; Hu, Zhong-Hua; Liu, Bin; Wang, Ye-Qiu; Liu, Jun-Cen; Qi, Yong-Hua; Li, Li-Jing

2016-01-01

Objective: Comparative study of type 2 diabetes and healthy controls by metabolomics methods to explore the pathogenesis of Type II diabetes. Methods: Gas chromatography - mass spectrometry (GC-MS) with a variety of multivariate statistical analysis methods to the healthy control group 58 cases, 68 cases of Type II diabetes group were analyzed. Chromatographic conditions: DB-5MS column; the carrier gas He; flow rate of 1 mL·min-1, the injection volume 1 uL; split ratio is 100: 1. MS condition...

LC-MS/MS Peptide Mapping with Automated Data Processing for Routine Profiling of N-Glycans in Immunoglobulins

Science.gov (United States)

Shah, Bhavana; Jiang, Xinzhao Grace; Chen, Louise; Zhang, Zhongqi

2014-06-01

Protein N-Glycan analysis is traditionally performed by high pH anion exchange chromatography (HPAEC), reversed phase liquid chromatography (RPLC), or hydrophilic interaction liquid chromatography (HILIC) on fluorescence-labeled glycans enzymatically released from the glycoprotein. These methods require time-consuming sample preparations and do not provide site-specific glycosylation information. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) peptide mapping is frequently used for protein structural characterization and, as a bonus, can potentially provide glycan profile on each individual glycosylation site. In this work, a recently developed glycopeptide fragmentation model was used for automated identification, based on their MS/MS, of N-glycopeptides from proteolytic digestion of monoclonal antibodies (mAbs). Experimental conditions were optimized to achieve accurate profiling of glycoforms. Glycan profiles obtained from LC-MS/MS peptide mapping were compared with those obtained from HPAEC, RPLC, and HILIC analyses of released glycans for several mAb molecules. Accuracy, reproducibility, and linearity of the LC-MS/MS peptide mapping method for glycan profiling were evaluated. The LC-MS/MS peptide mapping method with fully automated data analysis requires less sample preparation, provides site-specific information, and may serve as an alternative method for routine profiling of N-glycans on immunoglobulins as well as other glycoproteins with simple N-glycans.

Response surface methodology optimization of nickel (II) removal using pigeon pea pod bio sorbent

International Nuclear Information System (INIS)

Aravind, J.; Lenin, C.; Nancyflavia, C.; Rashika, P.; Saravanan, S.

2015-01-01

Pod of pigeon pea (Cajanus cajan), a cellulose rich agricultural residue, was investigated for its nickel binding efficiency. The influence of key physicochemical parameters such as contact time, initial metal ion concentration, adsorbent dosage and p H on nickel (II) removal was studied. The equilibrium time was found to be 45 min. The optimum Ni (II) removal was obtained at an initial metal ion concentration of 80 mg/l, p H of 9.0 and an adsorbent dose of 400 mg/100 ml. A search for optimal combination of key variables was studied by response surface methodology for maximum removal of nickel. The experiment encompassing 17 runs was established with the aid of Box–Behnken design. Owing to the reasonable agreement between predicted and adjusted R2 value (0.9714), the corresponding quadratic model gives the most appropriate relationship between the variables and response. The optimal point obtained was located in the valid region and the optimum adsorption parameters were predicted as an initial Ni (II) concentration of 60 mg/l, p H value of 9.0 and contact time of 75 min. Under these adsorption conditions, a maximum removal of 96.54 % of initial metal concentration was demonstrated.

Determination of imidazole derivatives by micellar electrokinetic chromatography combined with solid-phase microextraction using activated carbon-polymer monolith as adsorbent.

Science.gov (United States)

Shih, Yung-Han; Lirio, Stephen; Li, Chih-Keng; Liu, Wan-Ling; Huang, Hsi-Ya

2016-01-08

In this study, an effective method for the separation of imidazole derivatives 2-methylimidazole (2-MEI), 4- methylimidazole (4-MEI) and 2-acetyl-4-tetrahydroxybutylimidazole (THI) in caramel colors using cation-selective exhaustive injection and sweeping micellar electrokinetic chromatography (CSEI-sweeping-MEKC) was developed. The limits of detection (LOD) and quantitation (LOQ) for the CSEI-sweeping-MEKC method were in the range of 4.3-80μgL(-1) and 14-270μgL(-1), respectively. Meanwhile, a rapid fabrication activated carbon-polymer (AC-polymer) monolithic column as adsorbent for solid-phase microextraction (SPME) of imidazole colors was developed. Under the optimized SPME condition, the extraction recoveries for intra-day, inter-day and column-to-column were in the range of 84.5-95.1% (<6.3% RSDs), 85.6-96.1% (<4.9% RSDs), and 81.3-96.1% (<7.1% RSDs), respectively. The LODs and LOQs of AC-polymer monolithic column combined with CSEI-sweeping-MEKC method were in the range of 33.4-60.4μgL(-1) and 111.7-201.2μgL(-1), respectively. The use of AC-polymer as SPME adsorbent demonstrated the reduction of matrix effect in food samples such as soft drink and alcoholic beverage thereby benefiting successful determination of trace-level caramel colors residues using CSEI-sweeping-MEKC method. The developed AC-polymer monolithic column can be reused for more than 30 times without any significant loss in the extraction recovery for imidazole derivatives. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimization of a Pre-MEKC Separation SPE Procedure for Steroid Molecules in Human Urine Samples

Directory of Open Access Journals (Sweden)

Ilona Olędzka

2013-11-01

Full Text Available Many steroid hormones can be considered as potential biomarkers and their determination in body fluids can create opportunities for the rapid diagnosis of many diseases and disorders of the human body. Most existing methods for the determination of steroids are usually time- and labor-consuming and quite costly. Therefore, the aim of analytical laboratories is to develop a new, relatively low-cost and rapid implementation methodology for their determination in biological samples. Due to the fact that there is little literature data on concentrations of steroid hormones in urine samples, we have made attempts at the electrophoretic determination of these compounds. For this purpose, an extraction procedure for the optimized separation and simultaneous determination of seven steroid hormones in urine samples has been investigated. The isolation of analytes from biological samples was performed by liquid-liquid extraction (LLE with dichloromethane and compared to solid phase extraction (SPE with C18 and hydrophilic-lipophilic balance (HLB columns. To separate all the analytes a micellar electrokinetic capillary chromatography (MECK technique was employed. For full separation of all the analytes a running buffer (pH 9.2, composed of 10 mM sodium tetraborate decahydrate (borax, 50 mM sodium dodecyl sulfate (SDS, and 10% methanol was selected. The methodology developed in this work for the determination of steroid hormones meets all the requirements of analytical methods. The applicability of the method has been confirmed for the analysis of urine samples collected from volunteers—both men and women (students, amateur bodybuilders, using and not applying steroid doping. The data obtained during this work can be successfully used for further research on the determination of steroid hormones in urine samples.

Preliminary optimization experiments of coupled liquid hydrogen moderator for KENS-II

International Nuclear Information System (INIS)

Watanabe, N.; Kiyanagi, Y.; Inoue, K.; Furusaka, M.; Ikeda, S.; Arai, M.; Iwasa, H.

1989-01-01

As a preliminary optimization experiment on the cold-neutron source for KENS-II, energy and time distributions of cold neutrons emanating from coupled liquid-hydrogen moderators with and without a premoderator in a graphite reflector were measured and compared with those from a decoupled liquid-hydrogen moderator. The results showed that the energy spectra from the coupled liquid-hydrogen moderators are almost the same as those from a decoupled one. Relative gain of the former to the latter is fairly high, more than 5, and further increases with increasing wavelength. The broadening of the neutron pulse width in coupled moderators at the cold-neutron region is not so significant and only 1.5 times compared to the solid methane moderator presently operated at KENS-II. 2 refs., 12 figs., 1 tab

Optimizing Cu(II) removal from aqueous solution by magnetic nanoparticles immobilized on activated carbon using Taguchi method.

Science.gov (United States)

Ebrahimi Zarandi, Mohammad Javad; Sohrabi, Mahmoud Reza; Khosravi, Morteza; Mansouriieh, Nafiseh; Davallo, Mehran; Khosravan, Azita

2016-01-01

This study synthesized magnetic nanoparticles (Fe(3)O(4)) immobilized on activated carbon (AC) and used them as an effective adsorbent for Cu(II) removal from aqueous solution. The effect of three parameters, including the concentration of Cu(II), dosage of Fe(3)O(4)/AC magnetic nanocomposite and pH on the removal of Cu(II) using Fe(3)O(4)/AC nanocomposite were studied. In order to examine and describe the optimum condition for each of the mentioned parameters, Taguchi's optimization method was used in a batch system and L9 orthogonal array was used for the experimental design. The removal percentage (R%) of Cu(II) and uptake capacity (q) were transformed into an accurate signal-to-noise ratio (S/N) for a 'larger-the-better' response. Taguchi results, which were analyzed based on choosing the best run by examining the S/N, were statistically tested using analysis of variance; the tests showed that all the parameters' main effects were significant within a 95% confidence level. The best conditions for removal of Cu(II) were determined at pH of 7, nanocomposite dosage of 0.1 gL(-1) and initial Cu(II) concentration of 20 mg L(-1) at constant temperature of 25 °C. Generally, the results showed that the simple Taguchi's method is suitable to optimize the Cu(II) removal experiments.

Beta-N-Methylamino-l-Alanine: LC-MS/MS Optimization, Screening of Cyanobacterial Strains and Occurrence in Shellfish from Thau, a French Mediterranean Lagoon

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Damien Réveillon

2014-11-01

Full Text Available β-N-methylamino-l-alanine (BMAA is a neurotoxic non-protein amino acid suggested to be involved in neurodegenerative diseases. It was reported to be produced by cyanobacteria, but also found in edible aquatic organisms, thus raising concern of a widespread human exposure. However, the chemical analysis of BMAA and its isomers are controversial, mainly due to the lack of selectivity of the analytical methods. Using factorial design, we have optimized the chromatographic separation of underivatized analogues by a hydrophilic interaction chromatography coupled to tandem mass spectrometry (HILIC-MS/MS method. A combination of an effective solid phase extraction (SPE clean-up, appropriate chromatographic resolution and the use of specific mass spectral transitions allowed for the development of a highly selective and sensitive analytical procedure to identify and quantify BMAA and its isomers (in both free and total form in cyanobacteria and mollusk matrices (LOQ of 0.225 and 0.15 µg/g dry weight, respectively. Ten species of cyanobacteria (six are reported to be BMAA producers were screened with this method, and neither free nor bound BMAA could be found, while both free and bound DAB were present in almost all samples. Mussels and oysters collected in 2009 in the Thau Lagoon, France, were also screened, and bound BMAA and its two isomers, DAB and AEG, were observed in all samples (from 0.6 to 14.4 µg/g DW, while only several samples contained quantifiable free BMAA.

Confinement Sensing and Signal Optimization via Piezo1/PKA and Myosin II Pathways

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Wei-Chien Hung

2016-05-01

Full Text Available Summary: Cells adopt distinct signaling pathways to optimize cell locomotion in different physical microenvironments. However, the underlying mechanism that enables cells to sense and respond to physical confinement is unknown. Using microfabricated devices and substrate-printing methods along with FRET-based biosensors, we report that, as cells transition from unconfined to confined spaces, intracellular Ca2+ level is increased, leading to phosphodiesterase 1 (PDE1-dependent suppression of PKA activity. This Ca2+ elevation requires Piezo1, a stretch-activated cation channel. Moreover, differential regulation of PKA and cell stiffness in unconfined versus confined cells is abrogated by dual, but not individual, inhibition of Piezo1 and myosin II, indicating that these proteins can independently mediate confinement sensing. Signals activated by Piezo1 and myosin II in response to confinement both feed into a signaling circuit that optimizes cell motility. This study provides a mechanism by which confinement-induced signaling enables cells to sense and adapt to different physical microenvironments. : Hung et al. demonstrate that a Piezo1-dependent intracellular calcium increase negatively regulates protein kinase A (PKA as cells transit from unconfined to confined spaces. The Piezo1/PKA and myosin II signaling modules constitute two confinement-sensing mechanisms. This study provides a paradigm by which signaling enables cells to sense and adapt to different microenvironments.

Optimizing the injection straight of PEP II asymmetric B Factory at SLAC

International Nuclear Information System (INIS)

Bulos, F.; Bloom, E.; Davies-White, W.; Donald, M.; Fairfield, K.; Fieguth, T.; Godfrey, G.; Holtzapple, R.; Hutton, A.; Loew, G.; Miller, R.; Sukiennicki, B.; Wen, H.; Ronan, M.

1992-04-01

The asymmetric energy PEP II B Factory proposed as an upgrade of PEP at the Stanford Linear Accelerator Center requires both a powerful low emittance source of e - e + and a very reliable and efficient injection system. The SLC linac fulfills the source requirement very well. We describe here the optimization of the optics of the injection straight to insure reliable and efficient injection

Optimizing the injection straight of PEP II asymmetric B factory at SLAC

International Nuclear Information System (INIS)

Bulos, F.; Bloom, E.; Davies-White, W.; Donald, M.; Fairfield, K.; Fieguth, T.; Godfrey, G.; Holtzapple, R.; Hutton, A.; Loew, G.; Miller, R.; Sukiennicki, B.; Wen, H.

1992-01-01

The asymmetric energy PEP II B Factory proposed as an upgrade of PEP at the Stanford Linear Accelerator Center requires both a powerful low emittance source of e - e + and a very reliable and efficient injection system. The SLC linac fulfills the source requirement very well. We describe here the optimization of the optics of the injection straight to insure reliable and efficient injection

High-throughput, 384-well, LC-MS/MS CYP inhibition assay using automation, cassette-analysis technique, and streamlined data analysis.

Science.gov (United States)

Halladay, Jason S; Delarosa, Erlie Marie; Tran, Daniel; Wang, Leslie; Wong, Susan; Khojasteh, S Cyrus

2011-08-01

Here we describe a high capacity and high-throughput, automated, 384-well CYP inhibition assay using well-known HLM-based MS probes. We provide consistently robust IC(50) values at the lead optimization stage of the drug discovery process. Our method uses the Agilent Technologies/Velocity11 BioCel 1200 system, timesaving techniques for sample analysis, and streamlined data processing steps. For each experiment, we generate IC(50) values for up to 344 compounds and positive controls for five major CYP isoforms (probe substrate): CYP1A2 (phenacetin), CYP2C9 ((S)-warfarin), CYP2C19 ((S)-mephenytoin), CYP2D6 (dextromethorphan), and CYP3A4/5 (testosterone and midazolam). Each compound is incubated separately at four concentrations with each CYP probe substrate under the optimized incubation condition. Each incubation is quenched with acetonitrile containing the deuterated internal standard of the respective metabolite for each probe substrate. To minimize the number of samples to be analyzed by LC-MS/MS and reduce the amount of valuable MS runtime, we utilize timesaving techniques of cassette analysis (pooling the incubation samples at the end of each CYP probe incubation into one) and column switching (reducing the amount of MS runtime). Here we also report on the comparison of IC(50) results for five major CYP isoforms using our method compared to values reported in the literature.

NSGA-II Algorithm with a Local Search Strategy for Multiobjective Optimal Design of Dry-Type Air-Core Reactor

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Chengfen Zhang

2015-01-01

Full Text Available Dry-type air-core reactor is now widely applied in electrical power distribution systems, for which the optimization design is a crucial issue. In the optimization design problem of dry-type air-core reactor, the objectives of minimizing the production cost and minimizing the operation cost are both important. In this paper, a multiobjective optimal model is established considering simultaneously the two objectives of minimizing the production cost and minimizing the operation cost. To solve the multi-objective optimization problem, a memetic evolutionary algorithm is proposed, which combines elitist nondominated sorting genetic algorithm version II (NSGA-II with a local search strategy based on the covariance matrix adaptation evolution strategy (CMA-ES. NSGA-II can provide decision maker with flexible choices among the different trade-off solutions, while the local-search strategy, which is applied to nondominated individuals randomly selected from the current population in a given generation and quantity, can accelerate the convergence speed. Furthermore, another modification is that an external archive is set in the proposed algorithm for increasing the evolutionary efficiency. The proposed algorithm is tested on a dry-type air-core reactor made of rectangular cross-section litz-wire. Simulation results show that the proposed algorithm has high efficiency and it converges to a better Pareto front.

Validation of a for anaerobic bacteria optimized MALDI-TOF MS biotyper database: The ENRIA project.

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Veloo, A C M; Jean-Pierre, H; Justesen, U S; Morris, T; Urban, E; Wybo, I; Kostrzewa, M; Friedrich, A W

2018-03-12

Within the ENRIA project, several 'expertise laboratories' collaborated in order to optimize the identification of clinical anaerobic isolates by using a widely available platform, the Biotyper Matrix Assisted Laser Desorption Ionization Time-of-Flight Mass Spectrometry (MALDI-TOF MS). Main Spectral Profiles (MSPs) of well characterized anaerobic strains were added to one of the latest updates of the Biotyper database db6903; (V6 database) for common use. MSPs of anaerobic strains nominated for addition to the Biotyper database are included in this validation. In this study, we validated the optimized database (db5989 [V5 database] + ENRIA MSPs) using 6309 anaerobic isolates. Using the V5 database 71.1% of the isolates could be identified with high confidence, 16.9% with low confidence and 12.0% could not be identified. Including the MSPs added to the V6 database and all MSPs created within the ENRIA project, the amount of strains identified with high confidence increased to 74.8% and 79.2%, respectively. Strains that could not be identified using MALDI-TOF MS decreased to 10.4% and 7.3%, respectively. The observed increase in high confidence identifications differed per genus. For Bilophila wadsworthia, Prevotella spp., gram-positive anaerobic cocci and other less commonly encountered species more strains were identified with higher confidence. A subset of the non-identified strains (42.1%) were identified using 16S rDNA gene sequencing. The obtained identities demonstrated that strains could not be identified either due to the generation of spectra of insufficient quality or due to the fact that no MSP of the encountered species was present in the database. Undoubtedly, the ENRIA project has successfully increased the number of anaerobic isolates that can be identified with high confidence. We therefore recommend further expansion of the database to include less frequently isolated species as this would also allow us to gain valuable insight into the clinical

Metal components analysis of metallothionein-III in the brain sections of metallothionein-I and metallothionein-II null mice exposed to mercury vapor with HPLC/ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Kameo, Satomi; Nakai, Kunihiko; Kurokawa, Naoyuki; Satoh, Hiroshi [Tohoku University, Graduate School of Medicine, Aoba-ku, Sendai (Japan); Kanehisa, Tomokazu; Naganuma, Akira [Tohoku University, Graduate School of Pharmaceutical Sciences, Sendai (Japan)

2005-04-01

Mercury vapor is effectively absorbed via inhalation and easily passes through the blood-brain barrier; therefore, mercury poisoning with primarily central nervous system symptoms occurs. Metallothionein (MT) is a cysteine-rich metal-binding protein and plays a protective role in heavy-metal poisoning and it is associated with the metabolism of trace elements. Two MT isoforms, MT-I and MT-II, are expressed coordinately in all mammalian tissues, whereas MT-III is a brain-specific member of the MT family. MT-III binds zinc and copper physiologically and is seemed to have important neurophysiological and neuromodulatory functions. The MT functions and metal components of MTs in the brain after mercury vapor exposure are of much interest; however, until now they have not been fully examined. In this study, the influences of the lack of MT-I and MT-II on mercury accumulation in the brain and the changes of zinc and copper concentrations and metal components of MTs were examined after mercury vapor exposure by using MT-I, II null mice and 129/Sv (wild-type) mice as experimental animals. MT-I, II null mice and wild-type mice were exposed to mercury vapor or an air stream for 2 h and were killed 24 h later. The brain was dissected into the cerebral cortex, the cerebellum, and the hippocampus. The concentrations of mercury in each brain section were determined by cold vapor atomic absorption spectrometry. The concentrations of mercury, copper, and zinc in each brain section were determined by inductively coupled plasma mass spectrometry (ICP-MS). The mercury accumulated in brains after mercury vapor exposure for MT-I, II null mice and wild-type mice. The mercury levels of MT-I, II null mice in each brain section were significantly higher than those of wild-type mice after mercury vapor exposure. A significant change of zinc concentrations with the following mercury vapor exposure for MT-I, II null mice was observed only in the cerebellum analyzed by two-way analysis of

Biological removal of nickel (II by Bacillus sp. KL1 in different conditions: optimization by Taguchi statistical approach

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Taran Mojtaba

2015-09-01

Full Text Available Bioremediation is the removal of heavy-metals such as nickel (Ni using microorganisms and has been considered as an important field in the biotechnology. Isolation and characterization of microorganisms exhibiting bioremediation activities and their optimization to treat polluted wastewaters is a vital and difficult task in remediation technologies. In this study, investigation was carried out to isolate Ni (II remediating microbial strains from soils contaminated with municipal solid waste leachate. Furthermore, Taguchi design of experiments were used to evaluate the influence of concentration, pH, temperature, and time on bioremediation of Ni (II using isolated bacteria. This study concluded that Bacillus sp. KL1 is a Ni (II-resistant strain and had Ni (II bioremediation activity. The highest bioremediation of Ni (II was observed as 55.06% after 24 h at 30ºC, pH 7, and 100 ppm concentration. Moreover, it was also observed that concentration is the most effective factor in the bioremediation process. In conclusion, we have demonstrated that bacteria isolated from soils contaminated with garbage leachate have the Bacillus sp. KL1 bacteria which can efficiently uptake and eliminate Ni (II from contaminated sites and thus makes it possible to treat heavy-metal containing wastewaters in industry by using this microorganism at optimized conditions.

Dual cloud point extraction coupled with hydrodynamic-electrokinetic two-step injection followed by micellar electrokinetic chromatography for simultaneous determination of trace phenolic estrogens in water samples.

Science.gov (United States)

Wen, Yingying; Li, Jinhua; Liu, Junshen; Lu, Wenhui; Ma, Jiping; Chen, Lingxin

2013-07-01

A dual cloud point extraction (dCPE) off-line enrichment procedure coupled with a hydrodynamic-electrokinetic two-step injection online enrichment technique was successfully developed for simultaneous preconcentration of trace phenolic estrogens (hexestrol, dienestrol, and diethylstilbestrol) in water samples followed by micellar electrokinetic chromatography (MEKC) analysis. Several parameters affecting the extraction and online injection conditions were optimized. Under optimal dCPE-two-step injection-MEKC conditions, detection limits of 7.9-8.9 ng/mL and good linearity in the range from 0.05 to 5 μg/mL with correlation coefficients R(2) ≥ 0.9990 were achieved. Satisfactory recoveries ranging from 83 to 108% were obtained with lake and tap water spiked at 0.1 and 0.5 μg/mL, respectively, with relative standard deviations (n = 6) of 1.3-3.1%. This method was demonstrated to be convenient, rapid, cost-effective, and environmentally benign, and could be used as an alternative to existing methods for analyzing trace residues of phenolic estrogens in water samples.

COMPARISON OF COMMERCIAL LC MS/MS COMPATIBLE DETERGENTS WITH SODIUM DEOXYCHOLATE FOR SHOTGUN PROTEOMICS

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Caleb J. Porter

2014-12-01

Full Text Available In this study, we compared the performance of sodium deoxycholate (SDC with several commercially available LC MS/MS compatible detergents for digestion of complex proteomic mixtures. First, the parameters affecting in-solution digestion using SDC were investigated with a full factorial experimental design. Metrics explored were trypsin ratio, digestion time, and concentration of SDC. These parameters were not found to be statistically associated with total peptide identifications in the experimental space investigated. However, in terms of digestion efficiency, digestion time was highly significant (p = 0.0095 as determined by the percent of peptides identified with missed cleavages. The optimized protocol for peptide identification and throughput was used to compare the performance of SDC with various commercially available LC MS/MS compatible surfactants namely Invitrosol, RapiGest, and PPS Silent Surfactant. The detergents were found to be similar through comparisons of the total identified peptides and the hydrophobicity of recovered peptides. We found suitable recovery across a large range of SDC concentrations determined from a bicinchoninic acid (BCA assay. In a spike down experiment, no distinct differences in total number of peptide identifications were discovered when comparing PPS (Silent Surfactant and SDC for preparation of peptide samples derived from low protein amounts (< 20 µg. Combined, these results indicate that SDC is a cost effective alternative to other commonly used LC MS/MS compatible surfactants

Profiling the Oxylipin and Endocannabinoid Metabolome by UPLC-ESI-MS/MS in Human Plasma to Monitor Postprandial Inflammation.

Science.gov (United States)

Gouveia-Figueira, Sandra; Späth, Jana; Zivkovic, Angela M; Nording, Malin L

2015-01-01

Bioactive lipids, including oxylipins, endocannabinoids, and related compounds may function as specific biochemical markers of certain aspects of inflammation. However, the postprandial responsiveness of these compounds is largely unknown; therefore, changes in the circulating oxylipin and endocannabinoid metabolome in response to a challenge meal were investigated at six occasions in a subject who freely modified her usual diet. The dietary change, and especially the challenge meal itself, represented a modification of precursor fatty acid status, with expectedly subtle effects on bioactive lipid levels. To detect even the slightest alteration, highly sensitive ultra-performance liquid chromatography (UPLC) coupled to electrospray ionization (ESI) tandem mass spectrometry (MS/MS) methods for bioactive lipid profiling was employed. A previously validated UPLC-ESI-MS/MS method for profiling the endocannabinoid metabolome was used, while validation of an UPLC-ESI-MS/MS method for oxylipin analysis was performed with acceptable outcomes for a majority of the parameters according to the US Food and Drug Administration guidelines for linearity (0.9938 metabolome, caused by changes in diet and ii) responsiveness to a challenge meal for a subset of the oxylipin and endocannabinoid metabolome. To summarize, we have shown proof-of-concept of our UPLC-ESI-MS/MS bioactive lipid protocols for the purpose of monitoring subtle shifts, and thereby useful to address lipid-mediated postprandial inflammation.

Development of alternative methods for the determination of raloxifene hydrochloride in tablet dosage form

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Fernanda Rodrigues Salazar

2015-06-01

Full Text Available Three methods are proposed for the quantitative determination of raloxifene hydrochloride in pharmaceutical dosage form: ultraviolet method (UV high performance liquid chromatography (HPLC and micellar capillary electrophoresis (MEKC. These methods were developed and validated and showed good linearity, precision and accuracy. Also they demonstrated to be specific and robust. The HPLC and MEKC methods were tested in regards to be stability indicating methods and they showed to have this attribute. The UV method used methanol as solvent and optimal wavelength at 284 nm, obeying Lambert-Beer law in these conditions. The chromatographic conditions for the HPLC method included: NST column C18 (250 x 4.6 mm x 5 µm, mobile phase water:acetonitrile:triethylamine (67:33:0,3 v/v, pH 3.5, flow rate 1.0 mL min-1, injection volume 20.0 µl, UV detection 287 nm and analysis temperature 30 °C. The MEKC method was performed on a fused-silica capillary (40 cm effective length x 50 µm i.d. using as background electrolyte 35.0 mmol L-1 borate buffer and 50.0 mmol L-1 anionic detergent sodium dodecyl sulfate (SDS at pH 8.8. The capillary temperature was 32°C, applied voltage 25 kV, UV detection at 280 nm and injection was perfomed at 45 mBar for 4 s, hydrodimanic mode. In this MEKC method, potassium diclofenac (200.0 µg mL-1 was used as internal standard. All these methods were statistically analyzed and demonstrated to be equivalent for quantitative analysis of RLX in tablets and were successfully applied for the determination of the drug.

Optimization of HS-SPME/GC-MS analysis and its use in the profiling of illicit ecstasy tablets (Part 1).

Science.gov (United States)

Bonadio, Federica; Margot, Pierre; Delémont, Olivier; Esseiva, Pierre

2009-05-30

A headspace solid-phase microextraction procedure (HS-SPME) was developed for the profiling of traces present in 3,4-methylenedioxymethylampethamine (MDMA). Traces were first extracted using HS-SPME and then analyzed by gas chromatography-mass spectroscopy (GC-MS). The HS-SPME conditions were optimized using varying conditions. Optimal results were obtained when 40 mg of crushed MDMA sample was heated at 80 degrees C for 15 min, followed by extraction at 80 degrees C for 15 min with a polydimethylsiloxane/divinylbenzene coated fibre. A total of 31 compounds were identified as traces related to MDMA synthesis, namely precursors, intermediates or by-products. In addition some fatty acids used as tabletting materials and caffeine used as adulterant, were also detected. The use of a restricted set of 10 target compounds was also proposed for developing a screening tool for clustering samples having close profile. 114 seizures were analyzed using an SPME auto-sampler (MultiPurpose Samples MPS2), purchased from Gerstel GMBH & Co. (Germany), and coupled to GC-MS. The data was handled using various pre-treatment methods, followed by the study of similarities between sample pairs based on the Pearson correlation. The results show that HS-SPME, coupled with the suitable statistical method is a powerful tool for distinguishing specimens coming from the same seizure and specimens coming from different seizures. This information can be used by law enforcement personnel to visualize the ecstasy distribution network as well as the clandestine tablet manufacturing.

Distinctive and Complementary MS2 Fragmentation Characteristics for Identification of Sulfated Sialylated N-Glycopeptides by nanoLC-MS/MS Workflow

Science.gov (United States)

Kuo, Chu-Wei; Guu, Shih-Yun; Khoo, Kay-Hooi

2018-04-01

High sensitivity identification of sulfated glycans carried on specific sites of glycoproteins is an important requisite for investigation of molecular recognition events involved in diverse biological processes. However, aiming for resolving site-specific glycosylation of sulfated glycopeptides by direct LC-MS2 sequencing is technically most challenging. Other than the usual limiting factors such as lower abundance and ionization efficiency compared to analysis of non-glycosylated peptides, confident identification of sulfated glycopeptides among the more abundant non-sulfated glycopeptides requires additional considerations in the selective enrichment and detection strategies. Metal oxide has been applied to enrich phosphopeptides and sialylated glycopeptides, but its use to capture sulfated glycopeptides has not been investigated. Likewise, various complementary MS2 fragmentation modes have yet to be tested against sialylated and non-sialylated sulfoglycopeptides due to limited appropriate sample availability. In this study, we have investigated the feasibility of sequencing tryptic sulfated N-glycopeptide and its MS2 fragmentation characteristics by first optimizing the enrichment methods to allow efficient LC-MS detection and MS2 analysis by a combination of CID, HCD, ETD, and EThcD on hybrid and tribrid Orbitrap instruments. Characteristic sulfated glyco-oxonium ions and direct loss of sulfite from precursors were detected as evidences of sulfate modification. It is anticipated that the technical advances demonstrated in this study would allow a feasible extension of our sulfoglycomic analysis to sulfoglycoproteomics. [Figure not available: see fulltext.

Low-dose cone-beam CT via raw counts domain low-signal correction schemes: Performance assessment and task-based parameter optimization (Part II. Task-based parameter optimization).

Science.gov (United States)

Gomez-Cardona, Daniel; Hayes, John W; Zhang, Ran; Li, Ke; Cruz-Bastida, Juan Pablo; Chen, Guang-Hong

2018-05-01

Different low-signal correction (LSC) methods have been shown to efficiently reduce noise streaks and noise level in CT to provide acceptable images at low-radiation dose levels. These methods usually result in CT images with highly shift-variant and anisotropic spatial resolution and noise, which makes the parameter optimization process highly nontrivial. The purpose of this work was to develop a local task-based parameter optimization framework for LSC methods. Two well-known LSC methods, the adaptive trimmed mean (ATM) filter and the anisotropic diffusion (AD) filter, were used as examples to demonstrate how to use the task-based framework to optimize filter parameter selection. Two parameters, denoted by the set P, for each LSC method were included in the optimization problem. For the ATM filter, these parameters are the low- and high-signal threshold levels p l and p h ; for the AD filter, the parameters are the exponents δ and γ in the brightness gradient function. The detectability index d' under the non-prewhitening (NPW) mathematical observer model was selected as the metric for parameter optimization. The optimization problem was formulated as an unconstrained optimization problem that consisted of maximizing an objective function d'(P), where i and j correspond to the i-th imaging task and j-th spatial location, respectively. Since there is no explicit mathematical function to describe the dependence of d' on the set of parameters P for each LSC method, the optimization problem was solved via an experimentally measured d' map over a densely sampled parameter space. In this work, three high-contrast-high-frequency discrimination imaging tasks were defined to explore the parameter space of each of the LSC methods: a vertical bar pattern (task I), a horizontal bar pattern (task II), and a multidirectional feature (task III). Two spatial locations were considered for the analysis, a posterior region-of-interest (ROI) located within the noise streaks region

Determination of 48 fragrance allergens in toys using GC with ion trap MS/MS.

Science.gov (United States)

Lv, Qing; Zhang, Qing; Li, Wentao; Li, Haiyu; Li, Pi; Ma, Qiang; Meng, Xianshuang; Qi, Meiling; Bai, Hua

2013-11-01

This paper presents a method for the simultaneous determination of 48 fragrance allergens in four types of toys (plastic toys, play clays, plush toys, and paper toys) based on GC with ion trap MS/MS. Compared with single-stage MS, MS/MS is superior in terms of the qualification and quantification of a large range of compounds in complicated matrices. Procedures for extraction and purification were optimized for each toy type. The method proved to be linear over a wide range of concentrations for all analytes with correlation coefficients between 0.9768 and 0.9999. Validation parameters, namely, LODs and LOQs, ranged from 0.005-5.0 and from 0.02-20 mg/kg, respectively. Average recoveries of target compounds (spiked at three concentration levels) were in the range of 79.5-109.1%. Intraday and interday repeatabilities of the proposed method varied from 0.7-10.5% and from 3.1-13.4%, respectively. The proposed method was used to monitor fragrance allergens in commercial toy products. Our findings indicate that this method is an accurate and effective technique for analyzing fragrance allergens in materials composed of complex components. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Verification of propofol sulfate as a further human propofol metabolite using LC-ESI-QQQ-MS and LC-ESI-QTOF-MS analysis.

Science.gov (United States)

Maas, Alexandra; Maier, Christoph; Michel-Lauter, Beate; Broecker, Sebastian; Madea, Burkhard; Hess, Cornelius

2017-03-01

Propofol (2,6-diisopropylphenol) is a water-insoluble, intravenous anesthetic that is widely used for the induction and maintenance of anesthesia as well as for endoscopic and pediatric sedation. After admission, propofol undergoes extensive hepatic and extrahepatic metabolism, including direct conjugation to propofol glucuronide and hydroxylation to 2,6-diisopropyl-1,4-quinol. The latter substance subsequently undergoes phase II metabolism, resulting in the formation of further metabolites (1quinolglucuronide, 4quinolglucuronide and 4quinol-sulfate). Further minor phase I propofol metabolites (2-(ω-propanol)-6-isopropylphenol and 2-(ω-propanol)-6-isopropyl-1,4-quinol)) are also described. Due to its chemical structure with the phenolic hydroxyl group, propofol is also an appropriate substrate for sulfation by sulfotransferases. The existence of propofol sulfate was investigated by liquid chromatography electrospray ionization triple quadrupole mass spectrometry (LCESIQQQ-MS) and liquid chromatography electrospray ionization quadrupole time-of-flight mass spectrometry (LCESI-QTOF-MS). A propofol sulfate reference standard was used for identification and method development, yielding a precursor at m/z 257 (deprotonated propofol sulfate) and product ions at m/z 177 (deprotonated propofol) and m/z 80 ([SO3]-). Propofol sulfate - a further phase II metabolite of propofol - was verified in urine samples by LC-ESI-QQQ-MS and LC-ESI-QTOF-MS. Analyses of urine samples from five volunteers collected before and after propofol-induced sedation verified the presence of propofol sulfate in urine following propofol administration, whereas ascertained concentrations of this metabolite were significantly lower compared with detected propofol glucuronide concentrations. The existence of propofol sulfate as a further phase II propofol metabolite in humans could be verified by two different detection techniques (LCESIQQQ-MS and LC-ESI-QTOFMS) on the basis of a propofol sulfate

Optimization of ADC transfer curves for the Belle II pixel detector

Energy Technology Data Exchange (ETDEWEB)

Haidl, Jakob; Mueller, Felix; Moser, Hans-Guenther; Kiesling, Christian; Valentan, Manfred [Max-Planck-Institut fuer Physik, Muenchen (Germany); Koffmane, Christian [Halbleiterlabor der Max-Planck-Gesellschaft, Muenchen (Germany); Collaboration: Belle II-Collaboration

2016-07-01

The Super-KEKB accelerator at the KEK high energy research center in Tsukuba in Japan will provide a 40 times higher luminosity. To cope with this high luminosity the Belle detector is improved to Belle II, which includes the integration of a two layer DEPFET pixel detector (PXD) resulting in a higher vertex resolution. The task of the read-out electronics is to process the high data rate of the PXD. To fulfill these requirements three different types of ASICs were designed. The foremost of them called Drain Current Digitizer (DCD) converts the drain currents of the DEPFET pixel sensors into digital code. Since the PXD will be equipped with 160 DCDs automatic testing of the chips is needed. Analog to digital transfer curves are an appropriate tool for error recognition and optimization of the digitization process within the DCD. An overview of measurements and optimization strategies is presented.

Optimization studies on BEPC II future pre-injector with two SHBs

International Nuclear Information System (INIS)

Pei Shilun; Wang Shuhong; Gu Pengda; Liu Bo

2004-01-01

The BEPC II future pre-injector consists of a thermionic gun followed by two subharmonic bunchers (SHB), a travelling wave prebuncher and a travelling wave buncher. All components downstream of the gun are immersed in a solenoid field for transverse focusing. Beam dynamics simulation and optimization have been carried out with programs PARMELA and EGUN. SHBs' bunching voltage and bunching drift distance, prebuncher and buncher's phase and acceleration gradient, and solenoid field profile have been studied. The bunch charge limitation for 10 ps bunch length at the buncher exit is also investigated

Simultaneous determination of 15 phenolic constituents of Chinese black rice wine by HPLC-MS/MS with SPE.

Science.gov (United States)

Wang, Yutang; Liu, Yuanyuan; Xiao, Chunxia; Liu, Laping; Hao, Miao; Wang, Jianguo; Liu, Xuebo

2014-06-01

This study established a new method for quantitative and qualitative determination of certain components in black rice wine, a traditional Chinese brewed wine. Specifically, we combined solid-phase extraction and high-performance liquid chromatography (HPLC) with triple quadrupole mass spectrometry (MS/MS) to determine 8 phenolic acids, 3 flavonols, and 4 anthocyanins in black rice wine. First, we clean samples with OASIS HLB cartridges and optimized extraction parameters. Next, we performed separation on a SHIM-PACK XR-ODS column (I.D. 3.0 mm × 75 mm, 2.2 μm particle size) with a gradient elution of 50% aqueous acetonitrile (V/V) and water, both containing 0.2% formic acid. We used multiple-reaction monitoring scanning for quantification, with switching electrospray ion source polarity between positive and negative modes in a single chromatographic run. We detected 15 phenolic compounds properly within 38 min under optimized conditions. Limits of detection ranged from 0.008 to 0.030 mg/L, and average recoveries ranged from 60.8 to 103.1% with relative standard deviation ≤8.6%. We validated the method and found it to be sensitive and reliable for quantifying phenolic compounds in rice wine matrices. This study developed a new, reliable HPLC-MS/MS method for simultaneous determination of 15 bioactive components in black rice wine. This method was validated and found to be sensitive and reliable for quantifying phenolic compounds in rice wine. © 2014 Institute of Food Technologists®

Factors Associated with Neurologists' Provision of MS Patient Care

Science.gov (United States)

Halpern, Michael T.; Teixeira-Poit, Stephanie M.; Kane, Heather; Frost, Corey; Keating, Michael; Olmsted, Murrey

2014-01-01

Neurologists are central to providing quality care for individuals with MS. However, neurologist shortages may restrict access to care for MS patients. To examine factors influencing neurologists' provision of MS care, we surveyed 1,700 US neurologists to assess demographic/practice characteristics, training, and attitudes toward MS care. The study population consisted of 573 respondents: 87 (15.2%) MS subspecialists and 486 (84.8%) “other neurologists,” including subspecialists in other neurology areas (i.e., non-MS) and general neurologists. MS subspecialists indicating they “enjoy interacting with MS patients” had a significantly greater rate of MS patients seen per week. In separate analyses of the “other neurologists” group, the rate of MS patients seen was lower among neurologists in university-based groups or those practicing in major cities; female neurologists; and neurologists who indicated lack of sufficient knowledge regarding MS patient care. Rates of MS patients seen were significantly greater for other neurologists who agreed that MS care involved “ability to improve patient outcomes and quality of life”; “dynamic area with evolving treatment options”; and “enjoy interacting with MS patients.” Understanding factors influencing MS patient care by neurologists and developing policies for appropriate access to care is critical for optimal outcomes among this population. PMID:24949203

Factors Associated with Neurologists’ Provision of MS Patient Care

Directory of Open Access Journals (Sweden)

Michael T. Halpern

2014-01-01

Full Text Available Neurologists are central to providing quality care for individuals with MS. However, neurologist shortages may restrict access to care for MS patients. To examine factors influencing neurologists’ provision of MS care, we surveyed 1,700 US neurologists to assess demographic/practice characteristics, training, and attitudes toward MS care. The study population consisted of 573 respondents: 87 (15.2% MS subspecialists and 486 (84.8% “other neurologists,” including subspecialists in other neurology areas (i.e., non-MS and general neurologists. MS subspecialists indicating they “enjoy interacting with MS patients” had a significantly greater rate of MS patients seen per week. In separate analyses of the “other neurologists” group, the rate of MS patients seen was lower among neurologists in university-based groups or those practicing in major cities; female neurologists; and neurologists who indicated lack of sufficient knowledge regarding MS patient care. Rates of MS patients seen were significantly greater for other neurologists who agreed that MS care involved “ability to improve patient outcomes and quality of life”; “dynamic area with evolving treatment options”; and “enjoy interacting with MS patients.” Understanding factors influencing MS patient care by neurologists and developing policies for appropriate access to care is critical for optimal outcomes among this population.

New Protocol Based on UHPLC-MS/MS for Quantitation of Metabolites in Xylose-Fermenting Yeasts

Science.gov (United States)

Campos, Christiane Gonçalves; Veras, Henrique César Teixeira; de Aquino Ribeiro, José Antônio; Costa, Patrícia Pinto Kalil Gonçalves; Araújo, Katiúscia Pereira; Rodrigues, Clenilson Martins; de Almeida, João Ricardo Moreira; Abdelnur, Patrícia Verardi

2017-12-01

Xylose fermentation is a bottleneck in second-generation ethanol production. As such, a comprehensive understanding of xylose metabolism in naturally xylose-fermenting yeasts is essential for prospection and construction of recombinant yeast strains. The objective of the current study was to establish a reliable metabolomics protocol for quantification of key metabolites of xylose catabolism pathways in yeast, and to apply this protocol to Spathaspora arborariae. Ultra-high performance liquid chromatography coupled to tandem mass spectrometry (UHPLC-MS/MS) was used to quantify metabolites, and afterwards, sample preparation was optimized to examine yeast intracellular metabolites. S. arborariae was cultivated using xylose as a carbon source under aerobic and oxygen-limited conditions. Ion pair chromatography (IPC) and hydrophilic interaction liquid chromatography-tandem mass spectrometry (HILIC-MS/MS) were shown to efficiently quantify 14 and 5 metabolites, respectively, in a more rapid chromatographic protocol than previously described. Thirteen and eleven metabolites were quantified in S. arborariae under aerobic and oxygen-limited conditions, respectively. This targeted metabolomics protocol is shown here to quantify a total of 19 metabolites, including sugars, phosphates, coenzymes, monosaccharides, and alcohols, from xylose catabolism pathways (glycolysis, pentose phosphate pathway, and tricarboxylic acid cycle) in yeast. Furthermore, to our knowledge, this is the first time that intracellular metabolites have been quantified in S. arborariae after xylose consumption. The results indicated that fine control of oxygen levels during fermentation is necessary to optimize ethanol production by S. arborariae. The protocol presented here may be applied to other yeast species and could support yeast genetic engineering to improve second generation ethanol production. [Figure not available: see fulltext.

User's manual for the BNW-II optimization code for dry/wet-cooled power plants

Energy Technology Data Exchange (ETDEWEB)

Braun, D.J.; Bamberger, J.A.; Braun, D.J.; Faletti, D.W.; Wiles, L.E.

1978-05-01

The User's Manual describes how to operate BNW-II, a computer code developed by the Pacific Northwest Laboratory (PNL) as a part of its activities under the Department of Energy (DOE) Dry Cooling Enhancement Program. The computer program offers a comprehensive method of evaluating the cost savings potential of dry/wet-cooled heat rejection systems. Going beyond simple ''figure-of-merit'' cooling tower optimization, this method includes such items as the cost of annual replacement capacity, and the optimum split between plant scale-up and replacement capacity, as well as the purchase and operating costs of all major heat rejection components. Hence the BNW-II code is a useful tool for determining potential cost savings of new dry/wet surfaces, new piping, or other components as part of an optimized system for a dry/wet-cooled plant.

Comprehensive comparison of in silico MS/MS fragmentation tools of the CASMI contest: database boosting is needed to achieve 93% accuracy.

Science.gov (United States)

Blaženović, Ivana; Kind, Tobias; Torbašinović, Hrvoje; Obrenović, Slobodan; Mehta, Sajjan S; Tsugawa, Hiroshi; Wermuth, Tobias; Schauer, Nicolas; Jahn, Martina; Biedendieck, Rebekka; Jahn, Dieter; Fiehn, Oliver

2017-05-25

In mass spectrometry-based untargeted metabolomics, rarely more than 30% of the compounds are identified. Without the true identity of these molecules it is impossible to draw conclusions about the biological mechanisms, pathway relationships and provenance of compounds. The only way at present to address this discrepancy is to use in silico fragmentation software to identify unknown compounds by comparing and ranking theoretical MS/MS fragmentations from target structures to experimental tandem mass spectra (MS/MS). We compared the performance of four publicly available in silico fragmentation algorithms (MetFragCL, CFM-ID, MAGMa+ and MS-FINDER) that participated in the 2016 CASMI challenge. We found that optimizing the use of metadata, weighting factors and the manner of combining different tools eventually defined the ultimate outcomes of each method. We comprehensively analysed how outcomes of different tools could be combined and reached a final success rate of 93% for the training data, and 87% for the challenge data, using a combination of MAGMa+, CFM-ID and compound importance information along with MS/MS matching. Matching MS/MS spectra against the MS/MS libraries without using any in silico tool yielded 60% correct hits, showing that the use of in silico methods is still important.

Stars of type MS with evidence of white dwarf companions. [IUE, Main Sequence (MS)

Science.gov (United States)

Peery, Benjamin F., Jr.

1986-01-01

A search for white dwarf companions of MS-type stars was conducted, using IUE. The overendowments of these stars in typical S-process nuclides suggest that they, like the Ba II stars, may owe their peculiar compositions to earlier mass transfer. Short-wavelength IUE spectra show striking emission line variability in HD35155, HD61913, and 4 Ori; HD35155 and 4 Ori show evidence of white dwarf companions.

Selective quantitation of the neurotoxin BMAA by use of hydrophilic-interaction liquid chromatography-differential mobility spectrometry-tandem mass spectrometry (HILIC-DMS-MS/MS).

Science.gov (United States)

Beach, Daniel G; Kerrin, Elliott S; Quilliam, Michael A

2015-11-01

The neurotoxin β-N-methylamino-L-alanine (BMAA) has been reported in cyanobacteria and shellfish, raising concerns about widespread human exposure. However, inconsistent results for BMAA analysis have led to controversy. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) is the most appropriate method for analysis of BMAA, but the risk of interference from isomers, other sample components, and the electrospray background is still present. We have investigated differential mobility spectrometry (DMS) as an ion filter to improve selectivity in the hydrophilic interaction liquid chromatographic (HILIC)-MS/MS determination of BMAA. We obtained standards for two BMAA isomers not previously analyzed by HILIC-MS, β-amino-N-methylalanine and 3,4-diaminobutanoic acid, and the typically used 2,4-diaminobutanoic acid and N-(2-aminoethyl)glycine. DMS separation of BMAA from these isomers was achieved and optimized conditions were used to develop a sensitive and highly selective multidimensional HILIC-DMS-MS/MS method. This work revealed current technical limitations of DMS for trace quantitation, and practical solutions were implemented. Accurate control of low levels of DMS carrier gas modifier was essential, but required external metering. The linearity of our optimized method was excellent from 0.01 to 6 μmol L(-1). The instrumental LOD was 0.4 pg BMAA injected on-column and the estimated method LOD was 20 ng g(-1) dry weight for BMAA in sample matrix. The method was used to analyze cycad plant tissue, a cyanobacterial reference material, and mussel tissues, by use of isotope-dilution quantitation with deuterated BMAA. This confirmed the presence of BMAA and several of its isomers in cycad and mussel tissues, including commercially available mussel tissue reference materials certified for other biotoxins. Graphical Abstract Differential Mobility Spectrometry is used to increases the selectivity of BMAA analysis by HILIC-MS/MS.

Tunable, Flexible and Efficient Optimization of Control Pulses for Superconducting Qubits, part II - Applications

Science.gov (United States)

AsséMat, Elie; Machnes, Shai; Tannor, David; Wilhelm-Mauch, Frank

In part I, we presented the theoretic foundations of the GOAT algorithm for the optimal control of quantum systems. Here in part II, we focus on several applications of GOAT to superconducting qubits architecture. First, we consider a control-Z gate on Xmons qubits with an Erf parametrization of the optimal pulse. We show that a fast and accurate gate can be obtained with only 16 parameters, as compared to hundreds of parameters required in other algorithms. We present numerical evidences that such parametrization should allow an efficient in-situ calibration of the pulse. Next, we consider the flux-tunable coupler by IBM. We show optimization can be carried out in a more realistic model of the system than was employed in the original study, which is expected to further simplify the calibration process. Moreover, GOAT reduced the complexity of the optimal pulse to only 6 Fourier components, composed with analytic wrappers.

Loss of Propiconazole and Its Four Stereoisomers from the Water Phase of Two Soil-Water Slurries as Measured by Capillary Electrophoresis

Directory of Open Access Journals (Sweden)

Rebecca D. Miller

2011-08-01

Full Text Available Propiconazole is a chiral fungicide used in agriculture for control of many fungal diseases on a variety of crops. This use provides opportunities for pollution of soil and, subsequently, groundwater. The rate of loss of propiconazole from the water phase of two different soil-water slurries spiked with the fungicide at 50 mg/L was followed under aerobic conditions over five months; the t1/2 was 45 and 51 days for the two soil slurries. To accurately assess environmental and human risk, it is necessary to analyze the separate stereoisomers of chiral pollutants, because it is known that for most such pollutants, both biotransformation and toxicity are likely to be stereoselective. Micellar electrokinetic chromatography (MEKC, the mode of capillary electrophoresis used for analysis of neutral chemicals, was used for analysis of the four propiconazole stereoisomers with time in the water phase of the slurries. MEKC resulted in baseline separation of all stereoisomers, while GC-MS using a chiral column gave only partial separation. The four stereoisomers of propiconazole were lost from the aqueous phase of the slurries at experimentally equivalent rates, i.e., there was very little, if any, stereoselectivity. No loss of propiconazole was observed from the autoclaved controls of either soil, indicating that the loss from active samples was most likely caused by aerobic biotansformation, with a possible contribution by sorption to the non-autoclaved active soils. MEKC is a powerful tool for separation of stereoisomers and can be used to study the fate and transformation kinetics of chiral pesticides in water and soil.

On-line identification of lysergic acid diethylamide (LSD) in tablets using a combination of a sweeping technique and micellar electrokinetic chromatography/77 K fluorescence spectroscopy.

Science.gov (United States)

Fang, Ching; Liu, Ju-Tsung; Lin, Cheng-Huang

2003-03-01

This work describes a novel method for the accurate determination of lysergic acid diethylamide (LSD) in tablets. A technique involving sweeping-micellar electrokinetic chromatography (MEKC) was used for the initial on-line concentration and separation, after which a cryogenic molecular fluorescence experiment was performed at 77 K. Using this approach, not only the separation of LSD from the tablet extract was achieved, but on-line spectra were readily distinguishable and could be unambiguously assigned. The results are in agreement with analyses by gas chromatography-mass spectrometry (GC-MS). Thus, this method, which was found to be accurate, sensitive and rapid, has the potential for use as a reliable complementary method to GC-MS in such analyses.

Hydrogen (H) Isotope Composition of Type II Kerogen Extracted by Pyrolysis-GC-MS-IRMS: Terrestrial Shale Deposits as Martian Analogs

Science.gov (United States)

Socki, Richard A.; Pernia, Denet; Evans, Michael; Fu, Qi; Bissada, Kadry K.; Curiale, Joseph A.; Niles, Paul B.

2014-01-01

Described here is a technique for H isotope analysis of organic compounds pyrolyzed from kerogens isolated from gas- and liquids-rich shales. Application of this technique will progress the understanding of the use of H isotopes not only in potential kerogen occurrences on Mars, but also in terrestrial oil and gas resource plays. H isotope extraction and analyses were carried out utilizing a CDS 5000 Pyroprobe connected to a Thermo Trace GC interfaced with a Thermo MAT 253 IRMS. Also, a split of GC-separated products was sent to a DSQ II quadrupole MS to make qualitative and semi-quantitative compositional measurements of these products. Kerogen samples from five different basins (type II and II-S) were dehydrated (heated to 80 C overnight under vacuum) and analyzed for their H isotope compositions by Pyrolysis-GC-MS-TC-IRMS. This technique takes pyrolysis products separated via GC and reacts them in a high temperature conversion furnace (1450 C), which quantitatively forms H2. Samples ranging from 0.5 to 1.0mg in size, were pyrolyzed at 800 C for 30s. and separated on a Poraplot Q GC column. H isotope data from all kerogen samples typically show enrichment in D from low to high molecular weight. H2O average delta D = -215.2 per mille (V-SMOW), ranging from - 271.8 per mille for the Marcellus Shale to -51.9 per mille for a Polish shale. Higher molecular weight compounds like toluene (C7H8) have an average delta D of -89.7 per mille, ranging from -156.0 per mille for the Barnett Shale to -50.0 per mille for the Monterey Shale. We interpret these data as representative of potential H isotope exchange between hydrocarbons and sediment pore water during basin formation. Since hydrocarbon H isotopes readily exchange with water, these data may provide some useful information on gas-water or oil-water interaction in resource plays, and further as a possible indicator of paleoenvironmental conditions. Alternatively, our data may be an indication of H isotope exchange with

Screening of Chemical Dyes in Traditional Chinese Medicine by HPTLC-MS.

Science.gov (United States)

He, Fengyan; He, Yi; Zheng, Xiaowei; Wang, Ruizhong; Lu, Jing; Dai, Zhong; Ma, Shuangcheng

2018-05-01

It has been uncovered that chemical dyes are illegally used in traditional Chinese medicines to brighten color and cover up inferiority, which threaten the safety of patients. In the present study, an HPTLC-MS method was developed for the effective screening of 11 chemical dyes (Sudan I, II, III, and IV; 808 Scarlet; Sudan Red 7B; malachite green; Basic Orange 2; auramine; Orange II; and erythrosine) in traditional Chinese medicine (TCM) raw materials and Chinese patent medicines. Firstly, unwashed HPTLC plates were chosen by comparing the background signals of the TLC plates used directly and prewashed with analytical grade and HPLC grade solvents. Twice developments were conducted to isolate chemical dyes of different polarity. Possible adulterants were preliminarily identified by comparing Rf values and in situ UV-Vis spectra with those of the references. Further confirmation was conducted by tandem MS analysis via an elution head-based TLC-MS interface. Sudan I and IV, 808 Scarlet, and Orange II were successfully detected in eight batches of TCM. The proposed method could be applied as a reliable technology for the screening of chemical dyes in TCM.

RAId_aPS: MS/MS analysis with multiple scoring functions and spectrum-specific statistics.

Science.gov (United States)

Alves, Gelio; Ogurtsov, Aleksey Y; Yu, Yi-Kuo

2010-11-16

Statistically meaningful comparison/combination of peptide identification results from various search methods is impeded by the lack of a universal statistical standard. Providing an E-value calibration protocol, we demonstrated earlier the feasibility of translating either the score or heuristic E-value reported by any method into the textbook-defined E-value, which may serve as the universal statistical standard. This protocol, although robust, may lose spectrum-specific statistics and might require a new calibration when changes in experimental setup occur. To mitigate these issues, we developed a new MS/MS search tool, RAId_aPS, that is able to provide spectrum-specific-values for additive scoring functions. Given a selection of scoring functions out of RAId score, K-score, Hyperscore and XCorr, RAId_aPS generates the corresponding score histograms of all possible peptides using dynamic programming. Using these score histograms to assign E-values enables a calibration-free protocol for accurate significance assignment for each scoring function. RAId_aPS features four different modes: (i) compute the total number of possible peptides for a given molecular mass range, (ii) generate the score histogram given a MS/MS spectrum and a scoring function, (iii) reassign E-values for a list of candidate peptides given a MS/MS spectrum and the scoring functions chosen, and (iv) perform database searches using selected scoring functions. In modes (iii) and (iv), RAId_aPS is also capable of combining results from different scoring functions using spectrum-specific statistics. The web link is http://www.ncbi.nlm.nih.gov/CBBresearch/Yu/raid_aps/index.html. Relevant binaries for Linux, Windows, and Mac OS X are available from the same page.

User's manual for the BNW-II optimization code for dry/wet-cooled power plants

Energy Technology Data Exchange (ETDEWEB)

Braun, D.J.; Bamberger, J.A.; Braun, D.J.; Faletti, D.W.; Wiles, L.E.

1978-05-01

This volume provides a listing of the BNW-II dry/wet ammonia heat rejection optimization code and is an appendix to Volume I which gives a narrative description of the code's algorithms as well as logic, input and output information.

Analysis of benzodiazepines and their metabolites using DBS cards and LC-MS/MS.

Science.gov (United States)

Lee, Heesang; Park, Yujin; Jo, Jiyeong; In, Sangwhan; Park, Yonghoon; Kim, Eunmi; Pyo, Jaesung; Choe, Sanggil

2015-10-01

Dried Blood Spot (DBS) has been used a blood extraction method for inherited metabolic disorder screening since 1960s. With introduction of LC-MS/MS, not only DBS could be used to analysis drugs in small blood volume, but in various fields, such as toxicology, drug therapeutic monitoring, drug diagnostic screening, and illicit drugs. In toxicology field, many drugs (e.g. benzodiazepines, acetaminophen, small molecule drugs) have been tested with DBS. Compared with earlier blood extraction methods (SPE and LLE), DBS has lots of advantages; lower blood volume (less than 50μL), shorter analysis time caused by a more concise analysis procedure and lower cost. We optimized the DBS procedure and LC-MS/MS conditions for 18 benzodiazepines, seven benzodiazepine metabolites, and one z-drug (zolpidem) analysis in blood. 30μL of whole blood was spotted on FTA DMPK card C and dried for 2h in a desiccator. A 6-mm disk was punched and vortexed for 1min in a centrifuge tube with 300μL methanol/acetonitrile mixture (1:1, v/v). After evaporation, redissolved in 100μL mobile phase of LC-MS/MS and 5μL was injected. In the analysis for 26 target compounds in blood, all of the method validation parameters - LLOD, LLOQ, accuracy (intra- and inter-assay), and precision (intra- and inter-assay) - were satisfied with method validation criteria, within 15%. The results of matrix effect, recovery, and process efficiency were good. We developed a fast and reliable sample preparation method using DBS for 26 benzodiazepines, benzodiazepine metabolites, and z-drug (zolpidem). Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Application of Box-Behnken designs in parameters optimization of differential pulse anodic stripping voltammetry for lead(II) determination in two electrolytes.

Science.gov (United States)

Yu, Xiao-Lan; He, Yong

2017-06-05

Box-Behnken design was advantageous to parameters optimization of differential pulse anodic stripping voltammetry (DPASV) for the analysis of lead(II) with its high efficiency and accuracy. Five Box-Behnken designs were designed and conducted in the electrolyte of 0.1 mol/L acetate buffer and 0.1 mol/L HCl without the removal of oxygen. Significant parameters and interactions in each electrolyte were found (P-value Box-Behnken designs in parameters optimization of DPASV for lead(II) determination regardless of the electrolyte kinds.

Comparative Pharmacokinetics Study of Icariin and Icariside II in Rats

Directory of Open Access Journals (Sweden)

Tao Cheng

2015-12-01

Full Text Available To explore the pharmacokinetic properties of icariin (ICA and icariside II (ICA II following intragastric and intravenous administration in rats, a rapid and sensitive method by using ultra-performance liquid chromatography–tandem mass spectroscopy (UPLC-MS/MS was developed and validated for the simultaneous quantification of ICA and ICA II in rat plasma. The quantification was performed by using multiple reaction monitoring of the transitions m/z 677.1/531.1 for ICA, 515.1/369.1 for ICA II and 463.1/301.1 for diosmetin-7-O-β-d-glucopyranoside (IS. The assay showed linearity over the concentration range of 1.03–1032 ng/mL, with correlation coefficients of 0.9983 and 0.9977. Intra- and inter-day precision and accuracy were within 15%. The lower limit of quantification for both ICA and ICA II was 1.03 ng/mL, respectively. The recovery of ICA and ICA II was more than 86.2%. The LC-MS/MS method has been successfully used in the pharmacokinetic studies of ICA and ICA II in rats. The results indicated that 91.2% of ICA was transformed into ICA II after oral administration by rats, whereas only 0.4% of ICA was transformed into ICA II after intravenous administration. A comparison of the pharmacokinetics of ICA and ICA II after oral administration revealed that the Cmax and AUC0–t of ICA II were 3.8 and 13.0 times higher, respectively, than those of ICA. However, after intravenous administration, the Cmax and AUC0–t of ICA II were about only 12.1% and 4.2% of those of ICA. These results suggest that ICA and ICA II have distinct pharmacokinetic properties, and the insights obtained facilitate future pharmacological action studies.

Optimism and Adaptation to Multiple Sclerosis: What Does Optimism Mean?

NARCIS (Netherlands)

Fournier, M.; Ridder, D.T.D. de; Bensing, J.

1999-01-01

The aim of the present study was to determine the meaning of optimism by explicating the dimensions underlying the notion and their links to adjusting to MS. Seventy-three patients responded to optimism questionnaire s (i.e., the LOT, Generalized Self-Efficacy Scale) and outcome questionnaires.

Optimism and adaptation to multiple sclerosis: what does optimism mean?

NARCIS (Netherlands)

Fournier, M.; Ridder, D. de; Bensing, J.

1999-01-01

The aim of the present study was to determine the meaning of optimism by explicating the dimensions underlying the notion and their links to adjusting to MS. Seventy-three patients responded to optimism questionnaires (i.e., the LOT, Generalized Self-Efficacy Scale) and outcome questionnaires. In

Image Segmentation Parameter Optimization Considering Within- and Between-Segment Heterogeneity at Multiple Scale Levels: Test Case for Mapping Residential Areas Using Landsat Imagery

Directory of Open Access Journals (Sweden)

Brian A. Johnson

2015-10-01

Full Text Available Multi-scale/multi-level geographic object-based image analysis (MS-GEOBIA methods are becoming widely-used in remote sensing because single-scale/single-level (SS-GEOBIA methods are often unable to obtain an accurate segmentation and classification of all land use/land cover (LULC types in an image. However, there have been few comparisons between SS-GEOBIA and MS-GEOBIA approaches for the purpose of mapping a specific LULC type, so it is not well understood which is more appropriate for this task. In addition, there are few methods for automating the selection of segmentation parameters for MS-GEOBIA, while manual selection (i.e., trial-and-error approach of parameters can be quite challenging and time-consuming. In this study, we examined SS-GEOBIA and MS-GEOBIA approaches for extracting residential areas in Landsat 8 imagery, and compared naïve and parameter-optimized segmentation approaches to assess whether unsupervised segmentation parameter optimization (USPO could improve the extraction of residential areas. Our main findings were: (i the MS-GEOBIA approaches achieved higher classification accuracies than the SS-GEOBIA approach, and (ii USPO resulted in more accurate MS-GEOBIA classification results while reducing the number of segmentation levels and classification variables considerably.

An On-Target Desalting and Concentration Sample Preparation Protocol for MALDI-MS and MS/MS Analysis

DEFF Research Database (Denmark)

Zhang, Xumin; Wang, Quanhui; Lou, Xiaomin

2012-01-01

2DE coupled with MALDI-MS is one of the most widely used and powerful analytic technologies in proteomics study. The MALDI sample preparation method has been developed and optimized towards the combination of simplicity, sample-cleaning, and sample concentration since its introduction. Here we...... present a protocol of the so-called Sample loading, Matrix loading, and on-target Wash (SMW) method which fulfills the three criteria by taking advantage of the AnchorChip™ targets. Our method is extremely simple and no pre-desalting or concentration is needed when dealing with samples prepared from 2DE...

Non-enzymolytic adenosine barcode-mediated dual signal amplification strategy for ultrasensitive protein detection using LC-MS/MS.

Science.gov (United States)

Yang, Wen; Li, Tengfei; Shu, Chang; Ji, Shunli; Wang, Lei; Wang, Yan; Li, Duo; Mtalimanja, Michael; Sun, Luning; Ding, Li

2018-05-10

A method is described for the determination of proteins with LC-MS/MS enabled by a small molecule (adenosine) barcode and based on a double-recognition sandwich structure. The coagulation protein thrombin was chosen as the model analyte. Magnetic nanoparticles were functionalized with aptamer29 (MNP/apt29) and used to capture thrombin from the samples. MNP/apt29 forms a sandwich with functionalized gold nanoparticles modified with (a) aptamer15 acting as thrombin-recognizing element and (b) a large number of adenosine as mass barcodes. The sandwich formed (MNP/apt29-thrombin-apt15/AuNP/adenosine) can ben magnetically separated from the sample. Mass barcodes are subsequently released from the sandwiched structure for further analysis by adding 11-mercaptoundecanoic acid. Adenosine is then detected by LC-MS/MS as it reflects the level of thrombin with impressively amplified signal. Numerous adenosines introduced into the sandwich proportional to the target concentration further amplify the signal. Under optimized conditions, the response is linearly proportional to the thrombin concentration in the range of 0.02 nM to 10 nM, with a detection limit of 9 fM. The application of this method to the determination of thrombin in spiked plasma samples gave recoveries that ranged from 92.3% to 104.7%. Graphical abstract Schematic representation of a method for the determination of thrombin with LC-MS/MS. The method is based on a double-recognition sandwiched structure. With LC-MS/MS, mass barcodes (adenosine) are detected to quantify thrombin, which amplifies the detection signal impressively.

Optimal networks of future gravitational-wave telescopes

Science.gov (United States)

Raffai, Péter; Gondán, László; Heng, Ik Siong; Kelecsényi, Nándor; Logue, Josh; Márka, Zsuzsa; Márka, Szabolcs

2013-08-01

We aim to find the optimal site locations for a hypothetical network of 1-3 triangular gravitational-wave telescopes. We define the following N-telescope figures of merit (FoMs) and construct three corresponding metrics: (a) capability of reconstructing the signal polarization; (b) accuracy in source localization; and (c) accuracy in reconstructing the parameters of a standard binary source. We also define a combined metric that takes into account the three FoMs with practically equal weight. After constructing a geomap of possible telescope sites, we give the optimal 2-telescope networks for the four FoMs separately in example cases where the location of the first telescope has been predetermined. We found that based on the combined metric, placing the first telescope to Australia provides the most options for optimal site selection when extending the network with a second instrument. We suggest geographical regions where a potential second and third telescope could be placed to get optimal network performance in terms of our FoMs. Additionally, we use a similar approach to find the optimal location and orientation for the proposed LIGO-India detector within a five-detector network with Advanced LIGO (Hanford), Advanced LIGO (Livingston), Advanced Virgo, and KAGRA. We found that the FoMs do not change greatly in sites within India, though the network can suffer a significant loss in reconstructing signal polarizations if the orientation angle of an L-shaped LIGO-India is not set to the optimal value of ˜58.2°( + k × 90°) (measured counterclockwise from East to the bisector of the arms).

Optimal locations of piezoelectric patches for supersonic flutter control of honeycomb sandwich panels, using the NSGA-II method

International Nuclear Information System (INIS)

Nezami, M; Gholami, B

2016-01-01

The active flutter control of supersonic sandwich panels with regular honeycomb interlayers under impact load excitation is studied using piezoelectric patches. A non-dominated sorting-based multi-objective evolutionary algorithm, called non-dominated sorting genetic algorithm II (NSGA-II) is suggested to find the optimal locations for different numbers of piezoelectric actuator/sensor pairs. Quasi-steady first order supersonic piston theory is employed to define aerodynamic loading and the p-method is applied to find the flutter bounds. Hamilton’s principle in conjunction with the generalized Fourier expansions and Galerkin method are used to develop the dynamical model of the structural systems in the state-space domain. The classical Runge–Kutta time integration algorithm is then used to calculate the open-loop aeroelastic response of the system. The maximum flutter velocity and minimum voltage applied to actuators are calculated according to the optimal locations of piezoelectric patches obtained using the NSGA-II and then the proportional feedback is used to actively suppress the closed loop system response. Finally the control effects, using the two different controllers, are compared. (paper)

Identification and characterization of phenolics and terpenoids from ethanolic extracts of Phyllanthus species by HPLC-ESI-QTOF-MS/MS

Institute of Scientific and Technical Information of China (English)

Sunil Kumar; Awantika Singh; Brijesh Kumar

2017-01-01

Phyllanthus species plants are a rich source of phenolics and widely used due to their medicinal properties. A liquid chromatography–tandem mass spectrometry (LC–MS/MS) method was developed using high-pressure liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry (HPLC-ESI-QTOF-MS/MS) for the identification and characterization of quercetin, kaempferol, ellagic acid and their derivatives in ethanolic extracts of Phyllanthus species. The chromatographic separation was carried out on Thermo Betasil C8 column (250 mm×4.5 mm, 5 μm) using 0.1% formic acid in water and 0.1% formic acid in methanol as the mobile phase. The identification of diagnostic fragment ions and optimization of collision energies were carried out using 21 reference standards. Totally 51 compounds were identified which include 21 compounds identified and characterized unambiguously by comparison with their authentic standards and the remaining 30 were tentatively identified and characterized in ethanolic extracts of P. emblica, P. fraternus, P. amarus and P. niruri.

Multi-Objective Optimization of Pulsed Power Supply for a Railgun

Directory of Open Access Journals (Sweden)

Mehrdad Jafarboland

2011-07-01

Full Text Available A novel two-objective optimization design model for pulsed power supply (PPS is proposed in this paper. The objectives are the muzzle velocity and the stored-to-kinetic energy efficiency. The design variables include the operating voltage and the trigger delay times between segments. The acceleration of the armature is constrained to lower than 106 m/s2. The optimization results for nuzzle velocity and the efficiency separately show the following: 1 The acceleration constraint has great influence on the performance; 2 wide current pulse yields high velocity but low efficiency; and 3 The operating voltage has to be increased to accelerate a heavier projectile to a certain velocity or at a certain efficiency. Pareto solution fronts for various projectile masses are found using the nondominated sorting genetic algorithm (NSGA-II under the integration environment of MATLAB software.

Quantitation of sweet steviol glycosides by means of a HILIC-MS/MS-SIDA approach.

Science.gov (United States)

Well, Caroline; Frank, Oliver; Hofmann, Thomas

2013-11-27

Meeting the rising consumer demand for natural food ingredients, steviol glycosides, the sweet principle of Stevia rebaudiana Bertoni (Bertoni), have recently been approved as food additives in the European Union. As regulatory constraints require sensitive methods to analyze the sweet-tasting steviol glycosides in foods and beverages, a HILIC-MS/MS method was developed enabling the accurate and reliable quantitation of the major steviol glycosides stevioside, rebaudiosides A-F, steviolbioside, rubusoside, and dulcoside A by using the corresponding deuterated 16,17-dihydrosteviol glycosides as suitable internal standards. This quantitation not only enables the analysis of the individual steviol glycosides in foods and beverages but also can support the optimization of breeding and postharvest downstream processing of Stevia plants to produce preferentially sweet and least bitter tasting Stevia extracts.

Removal of Ni (II), Co (II) and Pb (II) ions from aqueous media using ...

African Journals Online (AJOL)

Removal of Ni (II), Co (II) and Pb (II) ions from aqueous media using Starch ... The results showed that 0.025 % loaded SSMNPs gave the optimal sorption ... constants (Lagergren and Pseudo-2nd-order) for Ni2+ and Co2+ adsorption were ... Langmuir correlation coefficients showed a better fit for the adsorption isotherms.

Optimization of a two-dimensional liquid chromatography-supercritical fluid chromatography-mass spectrometry (2D-LC-SFS-MS) system to assess "in-vivo" inter-conversion of chiral drug molecules.

Science.gov (United States)

Goel, Meenakshi; Larson, Eli; Venkatramani, C J; Al-Sayah, Mohammad A

2018-05-01

Enantioselective analysis is an essential requirement during the pharmaceutical development of chiral drug molecules. In pre-clinical and clinical studies, the Food and Drug Administration (FDA) mandates the assessment of "in vivo" inter-conversion of chiral drugs to determine their physiological effects. In-vivo analysis of the active pharmaceutical ingredient (API) and its potential metabolites could be quite challenging due to their low abundance (ng/mL levels) and matrix interferences. Therefore, highly selective and sensitive analytical techniques are required to separate the API and its metabolites from the matrix components and one another. Additionally, for chiral APIs, further analytical separation is required to resolve the API and its potential metabolites from their corresponding enantiomers. In this work, we demonstrate the optimization of our previously designed two-dimensional liquid chromatography-supercritical fluid chromatography-mass spectrometry (2D-LC-SFC -MS) system to achieve 10 ng/mL detection limit [1]. The first LC dimension, used as a desalting step, could efficiently separate the API from its potential metabolites and matrix components. The API and its metabolites were then trapped/focused on small trapping columns and transferred onto the second SFC dimension for chiral separation. Detection can be achieved by ultra-violet (UV) or MS detection. Different system parameters such as column dimensions, transfer volumes, trapping column stationary phase, system tubing internal diameter (i.d.), and detection techniques, were optimized to enhance the sensitivity of the 2D-LC-SFC-MS system. The limit of detection was determined to be 10 ng/mL. An application is described where a mouse hepatocyte treated sample was analyzed using the optimized 2D-LC-SFC-MS system with successful assessment of the ratio of API to its metabolite (1D-LC), as well as the corresponding enantiomeric excess values (% e.e.) of each (2D-SFC). Copyright © 2018

Study of gluing and wire bonding for the Belle II Silicon Vertex Detector

International Nuclear Information System (INIS)

Kang, K.H.; Hara, K.; Higuchi, T.; Hyun, H.J.; Jeon, H.B.; Joo, C.W.; Kah, D.H.; Kim, H.J.; Mibe, T.; Onuki, Y.; Park, H.; Rao, K.K.; Sato, N.; Shimizu, N.; Tanida, K.; Tsuboyama, T.; Uozumi, S.

2014-01-01

This paper describes an investigation into gluing and wire bonding for assembling the Silicon Vertex Detector (SVD) for the Belle II experiment at KEK in Japan. Optimizing the gluing of the silicon microstrip sensors, the support frame, and the readout flex cables is important for achieving the required mechanical precision. The wire bonding between the sensors and the readout electronic chips also needs special care to maximize the physics capability of the SVD. The silicon sensors and signal fan out flex circuits (pitch adapters) are glued and connected using wire bonding. We determine that gluing quality is important for achieving good bonding efficiency. The standard deviation in the glue thickness for the best result is measured to be 3.11 μm. Optimal machine parameters for wire bonding are determined to be 70 mW power, 20 gf force, and 20 ms for the pitch adapter and 60 mW power, 20 gf force, and 20 ms for the silicon strip sensors; these parameters provide a pull force of (10.92±0.72) gf. With these settings, 75% of the pitch adapters and 25% of the strip sensors experience the neck-broken type of break

Optimization study for Pb(II) and COD sequestration by consortium of sulphate-reducing bacteria

Science.gov (United States)

Verma, Anamika; Bishnoi, Narsi R.; Gupta, Asha

2017-09-01

In this study, initial minimum inhibitory concentration (MIC) of Pb(II) ions was analysed to check optimum concentration of Pb(II) ions at which the growth of sulphate-reducing consortium (SRC) was found to be maximum. 80 ppm of Pb(II) ions was investigated as minimum inhibitory concentration for SRC. Influence of electron donors such as lactose, sucrose, glucose and sodium lactate was examined to investigate best carbon source for growth and activity of sulphate-reducing bacteria. Sodium lactate was found to be the prime carbon source for SRC. Later optimization of various parameters was executed using Box-Behnken design model of response surface methodology to explore the effectiveness of three independent operating variables, namely, pH (5.0-9.0), temperature (32-42 °C) and time (5.0-9.0 days), on dependent variables, i.e. protein content, precipitation of Pb(II) ions, and removal of COD by SRC biomass. Maximum removal of COD and Pb(II) was observed to be 91 and 98 %, respectively, at pH 7.0 and temperature 37 °C and incubation time 7 days. According to response surface analysis and analysis of variance, the experimental data were perfectly fitted to the quadratic model, and the interactive influence of pH, temperature and time on Pb(II) and COD removal was highly significant. A high regression coefficient between the variables and response ( r 2 = 0.9974) corroborate eminent evaluation of experimental data by second-order polynomial regression model. SEM and Fourier transform infrared analysis was performed to investigate morphology of PbS precipitates, sorption mechanism and involved functional groups in metal-free and metal-loaded biomass of SRC for Pb(II) binding.

The cryogenic photon detection system for the ALPS II experiment. Characterization, optimization and background rejection

Energy Technology Data Exchange (ETDEWEB)

Bastidon, Noemi Alice Chloe

2017-01-12

The search for new fundamental bosons at very low mass is the central objective of the ALPS II experiment which is currently set up at the Deutsches Elektronen-Synchrotron (DESY, Hamburg). This experiment follows the light-shining-through-the-wall concept where photons could oscillate into weakly interacting light bosons in front of a wall and back into photons behind the wall, giving the impression that light can shine through a light tight barrier. In this concept, the background-free detection of near-infrared photons is required to fully exploit the sensitivity of the apparatus. The high efficiency single-photon detection in the near-infrared is challenging and requires a cryogenic detector. In this project, a Transition-Edge Sensor (TES) operated below 100mK will be used to detect single photons. This thesis focuses on the characterization and optimization of the ALPS II detector system including an Adiabatic Demagnetisation Refrigerator (ADR) with its two-stage pulse-tube cooler, two TES detectors and their Superconducting Quantum Interference Devices (SQUIDs) read-out system. Stability of the detection system over time is a priority in the ALPS II experiment. It is in this context that the cooling system has been subjected to many upgrades. In the framework of this thesis, the cooling setup has been studied in detail in order to optimize its cooling performances. Furthermore, the stability of the detector has been studied according to various criteria. Other essential parameters of the ALPS II experiment are its detection efficiency and its background rate. Indeed, the sensitivity of the experiment directly depends on these two characteristics. Both elements have been studied in depth in order to define if the chosen TES detector will meet ALPS IIc specifications.

The cryogenic photon detection system for the ALPS II experiment. Characterization, optimization and background rejection

International Nuclear Information System (INIS)

Bastidon, Noemi Alice Chloe

2017-01-01

The search for new fundamental bosons at very low mass is the central objective of the ALPS II experiment which is currently set up at the Deutsches Elektronen-Synchrotron (DESY, Hamburg). This experiment follows the light-shining-through-the-wall concept where photons could oscillate into weakly interacting light bosons in front of a wall and back into photons behind the wall, giving the impression that light can shine through a light tight barrier. In this concept, the background-free detection of near-infrared photons is required to fully exploit the sensitivity of the apparatus. The high efficiency single-photon detection in the near-infrared is challenging and requires a cryogenic detector. In this project, a Transition-Edge Sensor (TES) operated below 100mK will be used to detect single photons. This thesis focuses on the characterization and optimization of the ALPS II detector system including an Adiabatic Demagnetisation Refrigerator (ADR) with its two-stage pulse-tube cooler, two TES detectors and their Superconducting Quantum Interference Devices (SQUIDs) read-out system. Stability of the detection system over time is a priority in the ALPS II experiment. It is in this context that the cooling system has been subjected to many upgrades. In the framework of this thesis, the cooling setup has been studied in detail in order to optimize its cooling performances. Furthermore, the stability of the detector has been studied according to various criteria. Other essential parameters of the ALPS II experiment are its detection efficiency and its background rate. Indeed, the sensitivity of the experiment directly depends on these two characteristics. Both elements have been studied in depth in order to define if the chosen TES detector will meet ALPS IIc specifications.

Optimal networks of future gravitational-wave telescopes

International Nuclear Information System (INIS)

Raffai, Péter; Márka, Zsuzsa; Márka, Szabolcs; Gondán, László; Kelecsényi, Nándor; Heng, Ik Siong; Logue, Josh

2013-01-01

We aim to find the optimal site locations for a hypothetical network of 1–3 triangular gravitational-wave telescopes. We define the following N-telescope figures of merit (FoMs) and construct three corresponding metrics: (a) capability of reconstructing the signal polarization; (b) accuracy in source localization; and (c) accuracy in reconstructing the parameters of a standard binary source. We also define a combined metric that takes into account the three FoMs with practically equal weight. After constructing a geomap of possible telescope sites, we give the optimal 2-telescope networks for the four FoMs separately in example cases where the location of the first telescope has been predetermined. We found that based on the combined metric, placing the first telescope to Australia provides the most options for optimal site selection when extending the network with a second instrument. We suggest geographical regions where a potential second and third telescope could be placed to get optimal network performance in terms of our FoMs. Additionally, we use a similar approach to find the optimal location and orientation for the proposed LIGO-India detector within a five-detector network with Advanced LIGO (Hanford), Advanced LIGO (Livingston), Advanced Virgo, and KAGRA. We found that the FoMs do not change greatly in sites within India, though the network can suffer a significant loss in reconstructing signal polarizations if the orientation angle of an L-shaped LIGO-India is not set to the optimal value of ∼58.2°( + k × 90°) (measured counterclockwise from East to the bisector of the arms). (paper)

Liquid Chromatography Electrospray Ionization Tandem Mass Spectrometric (LC/ESI-MS/MS) Study for the Identification and Characterization of In Vivo Metabolites of Cisplatin in Rat Kidney Cancer Tissues: Online Hydrogen/Deuterium (H/D) Exchange Study.

Science.gov (United States)

Bandu, Raju; Ahn, Hyun Soo; Lee, Joon Won; Kim, Yong Woo; Choi, Seon Hee; Kim, Hak Jin; Kim, Kwang Pyo

2015-01-01

In vivo rat kidney tissue metabolites of an anticancer drug, cisplatin (cis-diamminedichloroplatinum [II]) (CP) which is used for the treatment of testicular, ovarian, bladder, cervical, esophageal, small cell lung, head and neck cancers, have been identified and characterized by using liquid chromatography positive ion electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) in combination with on line hydrogen/deuterium exchange (HDX) experiments. To identify in vivo metabolites, kidney tissues were collected after intravenous administration of CP to adult male Sprague-Dawley rats (n = 3 per group). The tissue samples were homogenized and extracted using newly optimized metabolite extraction procedure which involves liquid extraction with phosphate buffer containing ethyl acetate and protein precipitation with mixed solvents of methanol-water-chloroform followed by solid-phase clean-up procedure on Oasis HLB 3cc cartridges and then subjected to LC/ESI-HRMS analysis. A total of thirty one unknown in vivo metabolites have been identified and the structures of metabolites were elucidated using LC-MS/MS experiments combined with accurate mass measurements. Online HDX experiments have been used to further support the structural characterization of metabolites. The results showed that CP undergoes a series of ligand exchange biotransformation reactions with water and other nucleophiles like thio groups of methionine, cysteine, acetylcysteine, glutathione and thioether. This is the first research approach focused on the structure elucidation of biotransformation products of CP in rats, and the identification of metabolites provides essential information for further pharmacological and clinical studies of CP, and may also be useful to develop various effective new anticancer agents.

Chemometrically assisted development and validation of LC-MS/MS method for the analysis of potential genotoxic impurities in meropenem active pharmaceutical ingredient.

Science.gov (United States)

Grigori, Katerina; Loukas, Yannis L; Malenović, Anđelija; Samara, Vicky; Kalaskani, Anastasia; Dimovasili, Efi; Kalovidouri, Magda; Dotsikas, Yannis

2017-10-25

A sensitive Liquid Chromatography tandem mass spectrometry (LC-MS/MS) method was developed and validated for the quantitative analysis of three potential genotoxic impurities (318BP, M9, S5) in meropenem Active Pharmaceutical Ingredient (API). Due to the requirement for LOD values in ppb range, a high concentration of meropenem API (30mg/mL) had to be injected. Therefore, efficient determination of meropenem from its impurities became a critical aim of this study, in order to divert meropenem to waste, via a switching valve. ‎ After the selection of the important factors affecting analytes' elution, a Box-Behnken design was utilized to set the plan of experiments conducted with UV detector. As responses, the separation factor s between the last eluting impurity and meropenem, as well as meropenem retention factor k were used. Grid point search methodology was implemented aiming to obtain the optimal conditions that simultaneously comply to the conflicted criteria. Optimal mobile phase consisted of ACN, methanol and 0.09% HCOOH at a ratio 71/3.5/15.5v/v. All impurities and internal standard omeprazole were eluted before 7.5min and at 8.0min the eluents were directed to waste. The protocol was transferred to LC-MS/MS and validated according to ICH guidelines. Copyright © 2017 Elsevier B.V. All rights reserved.

Brain Functional Connectivity in MS: An EEG-NIRS Study

Science.gov (United States)

2015-10-01

1 AWARD NUMBER: W81XWH-14-1-0582 TITLE: Brain Functional Connectivity in MS: An EEG -NIRS Study PRINCIPAL INVESTIGATOR: Heather Wishart...Functional Connectivity in MS: An EEG -NIRS Study 5b. GRANT NUMBER W81XWH-14-1-0582 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER Heather...electrical ( EEG ) and blood volume and blood oxygen-based (NIRS and fMRI) signals, and to use the results to help optimize blood oxygen level

Determination of 3-MCPD by GC-MS/MS with PTV-LV injector used for a survey of Spanish foodstuffs.

Science.gov (United States)

León, Nuria; Yusà, Vicent; Pardo, Olga; Pastor, Agustín

2008-05-15

3-Monochloropropane-1,2-diol (3-MCPD) is the most common chemical contaminant of the group of chloropropanols. It can occur in foods and food ingredients at low levels as a result of processing, migration from packaging materials during storage and domestic cooking. A sensitive method for determination of 3-MCPD in foodstuffs using programmable temperature vaporization (PTV) with large-volume injection (LVI) gas chromatography (GC) with tandem mass spectrometry detection (MS/MS) has been developed and optimized. The optimization of the injection and detection parameters was carried out using statistical experimental design. A Plackett-Burman design was used to estimate the influence of resonance excitation voltage (REV), isolation time (IT), excitation time (ET), ion source temperature (IST), and electron energy (EE) on the analytical response in the ion trap mass spectrometer (ITMS). Only REV was found to have a statically significant effect. On the other hand, a central composite design was used to optimize the settings of injection temperature (T(inlet)), vaporization temperature (T(vap)), vaporization time (t(vap)) and flow (Flow). The optimized method has an instrumental limit of detection (signal-to-noise ratio 3:1) of 0.044 ng mL(-1). From Valencian, Spain, supermarkets 94 samples of foods were surveyed for 3-MCPD. Using the optimized method levels higher than the limit established for soy sauce by the European Union were found in some samples. The estimated daily intake of 3-MCPD throughout the investigated foodstuffs for adults and children was found about 0.005 and 0.01%, respectively, of the established provisional tolerable daily intake.

Studies on the metabolism of the α-pyrrolidinophenone designer drug methylenedioxy-pyrovalerone (MDPV) in rat and human urine and human liver microsomes using GC-MS and LC-high-resolution MS and its detectability in urine by GC-MS.

Science.gov (United States)

Meyer, Markus R; Du, Peng; Schuster, Frank; Maurer, Hans H

2010-12-01

Since the late 1990s, many derivatives of the α-pyrrolidinophenone (PPP) drug class appeared on the drugs of abuse market. The latest compound was described in 2009 to be a classic PPP carrying a methylenedioxy moiety remembering the classic entactogens (ecstasy). Besides Germany, 3,4-methylene-dioxypyrovalerone (MDPV) has appeared in many countries in Europe and Asia, indicating its worldwide importance for forensic and clinical toxicology. The aim of the presented work was to identify the phase I and II metabolites of MDPV and the human cytochrome-P450 (CYP) isoenzymes responsible for its main metabolic step(s). Finally, the detectability of MDPV in urine by the authors' systematic toxicological analysis (STA) should be studied. The urine samples were extracted after and without enzymatic cleavage of conjugates. The metabolites were separated and identified after work-up by GC-MS and liquid chromatography (LC)-high-resolution MS (LC-HR-MS). The studies revealed the following phase I main metabolic steps in rat and human: demethylenation followed by methylation, aromatic and side chain hydroxylation and oxidation of the pyrrolidine ring to the corresponding lactam as well as ring opening to the corresponding carboxylic acid. Using LC-HR-MS, most metabolite structures postulated according to GC-MS fragmentation could be confirmed and the phase II metabolites were identified. Finally, the formation of the initial metabolite demethylenyl-MDPV could be confirmed using incubation of human liver microsomes. Using recombinant human CYPs, CYP 2C19, CYP 2D6 and CYP 1A2 were found to catalyze this initial step. Finally, the STA allowed the detection of MDPV metabolites in the human urine samples. Copyright © 2010 John Wiley & Sons, Ltd.

Can neutral analytes be concentrated by transient isotachophoresis in micellar electrokinetic chromatography and how much?

Science.gov (United States)

Matczuk, Magdalena; Foteeva, Lidia S; Jarosz, Maciej; Galanski, Markus; Keppler, Bernhard K; Hirokawa, Takeshi; Timerbaev, Andrei R

2014-06-06

Transient isotachophoresis (tITP) is a versatile sample preconcentration technique that uses ITP to focus electrically charged analytes at the initial stage of CE analysis. However, according to the ruling principle of tITP, uncharged analytes are beyond its capacity while being separated and detected by micellar electrokinetic chromatography (MEKC). On the other hand, when these are charged micelles that undergo the tITP focusing, one can anticipate the concentration effect, resulting from the formation of transient micellar stack at moving sample/background electrolyte (BGE) boundary, which increasingly accumulates the analytes. This work expands the enrichment potential of tITP for MEKC by demonstrating the quantitative analysis of uncharged metal-based drugs from highly saline samples and introducing to the BGE solution anionic surfactants and buffer (terminating) co-ions of different mobility and concentration to optimize performance. Metallodrugs of assorted lipophilicity were chosen so as to explore whether their varying affinity toward micelles plays the role. In addition to altering the sample and BGE composition, optimization of the detection capability was achieved due to fine-tuning operational variables such as sample volume, separation voltage and pressure, etc. The results of optimization trials shed light on the mechanism of micellar tITP and render effective determination of selected drugs in human urine, with practical limits of detection using conventional UV detector. Copyright © 2014 Elsevier B.V. All rights reserved.

ICP-MS and elemental tags for the life sciences

Energy Technology Data Exchange (ETDEWEB)

Giesen, Charlotte

2012-08-07

Inductively coupled plasma mass spectrometry (ICP-MS) has been applied for the analysis of biomolecules due to its high sensitivity, wide linear dynamic range, and multielement capabilities. However, outside the elemental MS community the potential of this technique, e.g. for life sciences applications, is not yet fully exploited. Thus, the development of ICP-MS-based (immuno) assays for a wide range of medical (cancer diagnostics, cisplatin toxicity studies), biochemical (DNA microarray, single cell analysis), and environmental (analysis of comestible goods) applications was accomplished by utilization of chemical labels. Laser ablation (LA)-ICP-MS was employed for the direct analysis of solid samples like microarrays and thin tissue sections. An immunoassay was developed for ochratoxin A (OTA) determination in wine, and ICP-MS detection was compared to conventional photometry by gold nanoparticle tagging and horseradish peroxidase, respectively. Detection limits of the assay were optimized to 0.003 {mu}g L{sup -1}, and the quantification range was 0.01-1 {mu}g L{sup -1} for both methods. For LA-ICP-MS-based DNA microarray detection, gold nanoparticle tags were specifically introduced via a streptavidin-biotin linkage. In immunohistochemistry (IHC), up to 20 tumor markers are routinely evaluated for one patient and thus, a common analysis results in a series of time consuming staining procedures. Hence, LA-ICP-MS was elaborated as a detection tool for a novel, multiplexed IHC analysis of tissue sections. Different lanthanides were employed for the simultaneous detection of up to three tumor markers (Her 2, CK 7, and MUC 1) in a breast cancer tissue. Additionally, iodine was employed as a labeling reagent, and a new LA-ICP-MS method for single cell and cell nucleus imaging was developed at 4 {mu}m laser spot size. Iodine was also applied as a new internal standard for tissue samples. Moreover, Pt-protein complexes separated by an optimized 1D and 2D gel

Thallium (III) determination in the Baltic seawater samples by ICP MS after preconcentration on SGX C18 modified with DDTC.

Science.gov (United States)

Krasnodębska-Ostręga, Beata; Sadowska, Monika; Piotrowska, Katarzyna; Wojda, Marta

2013-08-15

The main difficulty of speciation analysis of thallium lies in extremely low concentrations of Tl(III) in comparison to Tl(I), which is the dominating form of thallium in environmental samples. In this study, a sensitive method is presented for separation of trace amounts of Tl(III) from Tl(I) and preconcentration of Tl(III) using octadecyl silica gel modified with diethyldithiocarbamate (DDTC). Under optimal conditions, only Tl(III) is retained on the sorbent, and then eluted with 96% ethanol. After chemical decomposition of Tl(III)-DDTC complex, thallium is determined by inductively coupled plasma mass spectrometry. High performance liquid chromatography with ICP MS detection was used to control the correctness of the obtained results. Parameters affecting solid phase extraction (SPE) such as pH, type, concentration and volume of eluent, breakthrough volume, and the impact of sample salinity (chlorides) and other interfering ions (Cd(II), Zn(II), Pb(II), Cu(II), Sn(II)) were investigated. The limit of detection (LOD), evaluated for 2 mL of sample solution, was 0.10 ng for Tl(I) and 0.43 ng for Tl(III). The method was applied to the determination of Tl(I) and Tl(III) in the Baltic seawater samples enriched in both thallium species. Copyright © 2013 Elsevier B.V. All rights reserved.

Analysis of phytochemical variations in dioecious Tinospora cordifolia stems using HPLC/QTOF MS/MS and UPLC/QqQLIT -MS/MS.

Science.gov (United States)

Bajpai, Vikas; Singh, Awantika; Chandra, Preeti; Negi, M P S; Kumar, Nikhil; Kumar, Brijesh

2016-01-01

The stem of dioecious Tinospora cordifolia (Menispermaceae) is a commonly used traditional Ayurvedic medicine in India having several therapeutic properties. To develop and validate LC-MS methods for the identification and simultaneous quantitation of various secondary metabolites and to study metabolomic variations in the stem of male and female plants. Ethanolic extract of stems were analysed by HPLC/ESI-QTOF-MS/MS for rapid screening of bioactive phytochemicals. High resolution MS and MS/MS in positive ESI mode were used for structural investigation of secondary metabolites. An UPLC/ESI-QqQ(LIT) -MS/MS method in MRM mode was developed and validated for the simultaneous quantitation of five bioactive alkaloids. Identification and characterisation of 36 metabolites including alkaloids, sesquiterpenes and phytoecdysteroids were performed using LC-MS and MS/MS techniques. The bioactive alkaloids such as jatrorrhizine, magnoflorine, isocorydine, palmatine and tetrahydropalmatine were successfully quantified in male and female plants. The mean abundances of magnoflorine jatrorrhizine, and oblongine were significantly (P Phytochemicals in the stem of male and female Tinospora cordifolia showed significant qualitative and quantitative variations. LC-MS and MS/MS methods can be used to differentiate between male and female plants based on their chemical profiles and quantities of the marker bioactive alkaloids. This chemical composition difference was also evident during vegetative stage when there were no male and female flowers. Copyright © 2015 John Wiley & Sons, Ltd.

Determination of Glyphosate Levels in Breast Milk Samples from Germany by LC-MS/MS and GC-MS/MS

NARCIS (Netherlands)

Steinborn, Angelika; Alder, Lutz; Michalski, Britta; Zomer, Paul; Bendig, Paul; Martinez, Sandra Aleson; Mol, Hans G.J.; Class, Thomas J.; Costa Pinheiro, Nathalie

2016-01-01

This study describes the validation and application of two independent analytical methods for the determination of glyphosate in breast milk. They are based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS), respectively. For

Virtual screening and optimization of Type II inhibitors of JAK2 from a natural product library.

Science.gov (United States)

Ma, Dik-Lung; Chan, Daniel Shiu-Hin; Wei, Guo; Zhong, Hai-Jing; Yang, Hui; Leung, Lai To; Gullen, Elizabeth A; Chiu, Pauline; Cheng, Yung-Chi; Leung, Chung-Hang

2014-11-21

Amentoflavone has been identified as a JAK2 inhibitor by structure-based virtual screening of a natural product library. In silico optimization using the DOLPHIN model yielded analogues with enhanced potency against JAK2 activity and HCV activity in cellulo. Molecular modeling and kinetic experiments suggested that the analogues may function as Type II inhibitors of JAK2.

Evaluation of SDS depletion using an affinity spin column and IMS-MS detection

Energy Technology Data Exchange (ETDEWEB)

Hengel, Shawna M.; Floyd, Erica A.; Baker, Erin Shammel; Zhao, Rui; Wu, Si; Pasa-Tolic, Ljiljana

2012-11-01

While the use of detergents is necessary for a variety of protein isolation preparation protocols, often prior to mass spectral (MS) analysis, they are not compatible with MS analysis due to ion suppression and adduct formation. This manuscript describes optimization of detergent removal, using commercially available SDS depletion spin columns containing an affinity resin, providing for both increased protein recovery and thorough SDS removal. Ion mobility spectrometry coupled with mass spectrometry (IMS-MS) allowed for a concurrent analysis of both analyte and detergent. In the case of both proteins and peptides, higher detergent concentrations than previously reported provided an increase of sample recovery; however there was a limit as SDS was detected by IMS-MS at higher levels of SDS indicating incomplete detergent depletion. The results also suggest optimal conditions for SDS removal are dependent on the sample concentration. Overall, this study provides a useful guide for proteomic studies where SDS is required for efficient sample preparation.

A Proof of Concept to Bridge the Gap between Mass Spectrometry Imaging, Protein Identification and Relative Quantitation: MSI~LC-MS/MS-LF

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Laëtitia Théron

2016-10-01

Full Text Available Mass spectrometry imaging (MSI is a powerful tool to visualize the spatial distribution of molecules on a tissue section. The main limitation of MALDI-MSI of proteins is the lack of direct identification. Therefore, this study focuses on a MSI~LC-MS/MS-LF workflow to link the results from MALDI-MSI with potential peak identification and label-free quantitation, using only one tissue section. At first, we studied the impact of matrix deposition and laser ablation on protein extraction from the tissue section. Then, we did a back-correlation of the m/z of the proteins detected by MALDI-MSI to those identified by label-free quantitation. This allowed us to compare the label-free quantitation of proteins obtained in LC-MS/MS with the peak intensities observed in MALDI-MSI. We managed to link identification to nine peaks observed by MALDI-MSI. The results showed that the MSI~LC-MS/MS-LF workflow (i allowed us to study a representative muscle proteome compared to a classical bottom-up workflow; and (ii was sparsely impacted by matrix deposition and laser ablation. This workflow, performed as a proof-of-concept, suggests that a single tissue section can be used to perform MALDI-MSI and protein extraction, identification, and relative quantitation.

Optimized expanded ensembles for simulations involving molecular insertions and deletions. II. Open systems

Science.gov (United States)

Escobedo, Fernando A.

2007-11-01

In the Grand Canonical, osmotic, and Gibbs ensembles, chemical potential equilibrium is attained via transfers of molecules between the system and either a reservoir or another subsystem. In this work, the expanded ensemble (EXE) methods described in part I [F. A. Escobedo and F. J. Martínez-Veracoechea, J. Chem. Phys. 127, 174103 (2007)] of this series are extended to these ensembles to overcome the difficulties associated with implementing such whole-molecule transfers. In EXE, such moves occur via a target molecule that undergoes transitions through a number of intermediate coupling states. To minimize the tunneling time between the fully coupled and fully decoupled states, the intermediate states could be either: (i) sampled with an optimal frequency distribution (the sampling problem) or (ii) selected with an optimal spacing distribution (staging problem). The sampling issue is addressed by determining the biasing weights that would allow generating an optimal ensemble; discretized versions of this algorithm (well suited for small number of coupling stages) are also presented. The staging problem is addressed by selecting the intermediate stages in such a way that a flat histogram is the optimized ensemble. The validity of the advocated methods is demonstrated by their application to two model problems, the solvation of large hard spheres into a fluid of small and large spheres, and the vapor-liquid equilibrium of a chain system.

The multi-objective optimization of the horizontal-axis marine current turbine based on NSGA-II algorithm

International Nuclear Information System (INIS)

Zhu, G J; Guo, P C; Luo, X Q; Feng, J J

2012-01-01

The present paper describes a hydrodynamic optimization technique for horizontal-axial marine current turbine. The pitch angle distribution is important to marine current turbine. In this paper, the pitch angle distribution curve is parameterized as four control points by Bezier curve method. The coordinates of the four control points are chosen as optimization variables, and the sample space are structured according to the Box-Behnken experimental design method (BBD). Then the power capture coefficient and axial thrust coefficient in design tip-speed ratio is obtained for all the elements in the sample space by CFD numerical simulation. The power capture coefficient and axial thrust are chosen as objective function, and quadratic polynomial regression equations are constructed to fit the relationship between the optimization variables and each objective function according to response surface model. With the obtained quadratic polynomial regression equations as performance prediction model, the marine current turbine is optimized using the NSGA-II multi-objective genetic algorithm, which finally offers an improved marine current turbine.

In vivo diabetic wound healing effect and HPLC–DAD–ESI–MS/MS profiling of the methanol extracts of eight Aloe species

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Abeer M. El Sayed

Full Text Available Abstract Genus Aloe, Xanthorrhoeaceae, is well distributed all over Egypt, and many species have been used as medicinal plants; mainly reported to prevent cardiovascular diseases, cancer and diabetes. This study attempts to analyze the secondary metabolites in the methanol extract of the leaves of eight Aloe species; A. vera (L. Burm. f., A. arborescens Mill., A. eru A. Berger, A. grandidentata Salm-Dyck, A. perfoliata L., A. brevifolia Mill., A. saponaria Haw. and A. ferox Mill. growing in Egypt. For this aim HPLC–DAD–MS/MS in negative ion mode was used. Although belonging to the same genus, the composition of each species presented different particularities. Seventy one compounds were identified in the investigated Aloe species, of which cis-p-coumaric acid derivaties, 3,4-O-(E caffeoylferuloylquinic acid and caffeoyl quinic acid hexoside were the most common phenolic acids identified. Aloeresin E and isoaloeresin D, 2'-O-feruloylaloesin were the common anthraquinones identified. Lucenin II, vicenin II, and orientin were the common identified flavonoids in the investigated Aloe species. 6'-Malonylnataloin, aloe-emodin-8-O-glucoside, flavone-6,8-di-C-glucosides could be considered as chemotaxonomic markers for the investigated Aloe species. The eight Aloe species had significant anti-inflammatory activity, in addition to the significant acceleration of diabetic wound healing in rats following topical application of the methanol extracts of their leaves. This is the first simultaneous characterization and qualitative determination of multiple phenolic compounds in Aloe species from locally grown cultivars in Egypt using HPLC–DAD–MS/MS, which can be applied to standardize the quality of different Aloe species and the future design of nutraceuticals and cosmetic preparations.

CEC-atmospheric pressure ionization MS of pesticides using a surfactant-bound monolithic column.

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Gu, Congying; Shamsi, Shahab A

2010-04-01

A surfactant bound poly (11-acrylaminoundecanoic acid-ethylene dimethacrylate) monolithic column was simply prepared by in situ co-polymerization of 11-acrylaminoundecanoic acid and ethylene dimethacrylate with 1-propanol, 1,4-butanediol and water as porogens in 100 microm id fused-silica capillary in one step. This column was used in CEC-atmospheric pressure photoionization (APPI)-MS system for separation and detection of N-methylcarbamates pesticides. Numerous parameters are optimized for CEC-APPI-MS. After evaluation of the mobile phase composition, sheath liquid composition and the monolithic capillary outlet position, a fractional factorial design was selected as a screening procedure to identify factors of ionization source parameters, such as sheath liquid flow rate, drying gas flow rate, drying gas temperature, nebulizing gas pressure, vaporizer temperature and capillary voltage, which significantly influence APPI-MS sensitivity. A face-centered central composite design was further utilized to optimize the most significant parameters and predict the best sensitivity. Under optimized conditions, S/Ns around 78 were achieved for an injection of 100 ng/mL of each pesticide. Finally, this CEC-APPI-MS method was successfully applied to the analysis of nine N-methylcarbamates in spiked apple juice sample after solid phase extraction with recoveries in the range of 65-109%.

ESI-MS studies of the reactions of novel platinum(II) complexes containing O,O'-chelated acetylacetonate and sulfur ligands with selected model proteins.

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Marzo, Tiziano; De Pascali, Sandra A; Gabbiani, Chiara; Fanizzi, Francesco P; Messori, Luigi; Pratesi, Alessandro

2017-08-01

A group of mixed-ligand Pt(II) complexes bearing acetylacetonate and sulphur ligands were recently developed in the University of Lecce as a new class of prospective anticancer agents that manifested promising pharma-cological properties in preliminary in vitro and in vivo tests. Though modelled on the basis of cisplatin, these Pt(II) complexes turned out to exhibit a profoundly distinct mode of action as they were found to act mainly on non-genomic targets rather than on DNA. Accordingly, we have explored here their reactions with two representative model proteins through an established ESI-MS procedure with the aim to describe their general interaction mechanism with protein targets. A pronounced reactivity with the tested proteins was indeed documented; the nature of the resulting metallodrug-protein interactions could be characterised in depth in the various cases. Preferential binding to protein targets compared to DNA is supported by independent ICP-OES measurements. The implications of these findings are discussed.

Finding of pesticides in fashionable fruit juices by LC-MS/MS and GC-MS/MS.

Science.gov (United States)

Tran, Kevin; Eide, David; Nickols, Susan M; Cromer, Michele R; Sabaa-Srur, Armando; Smith, Robert E

2012-10-15

Products labelled as containing extracts from two mushrooms (cordyceps plus reishi) and the juices from açaí, goji, mangosteen, noni, pomegranate, and sea buckthorn have been analysed for 174 different pesticides, using the validated QuEChERS method for sample preparation and electrospray LC-MS/MS in the positive ion mode for analysis. Pesticides were found in 10 of the 21 samples analysed. Most pesticides found were below the tolerance levels (1-6 μg/g, depending on the pesticide), but some were not. This included boscalid, dimethomorph, iprovalicarb, pyridaben, pyrimethanil, and imazalil, for which there is no tolerance reported or zero tolerance in any fruit. However, genuine açaí that was harvested in the state of Pará and lyophilised in Rio de Janeiro had no detectable pesticides, when analysed by both LC-MS/MS and GC-MS/MS, which can detect 213 more pesticides and industrial chemicals. Likewise no pesticides were found in one sample each of cordyceps plus reishi, sea buckthorn and noni. Published by Elsevier Ltd.

Segmental analysis of amphetamines in hair using a sensitive UHPLC-MS/MS method.

Science.gov (United States)

Jakobsson, Gerd; Kronstrand, Robert

2014-06-01

A sensitive and robust ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for quantification of amphetamine, methamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxy methamphetamine in hair samples. Segmented hair (10 mg) was incubated in 2M sodium hydroxide (80°C, 10 min) before liquid-liquid extraction with isooctane followed by centrifugation and evaporation of the organic phase to dryness. The residue was reconstituted in methanol:formate buffer pH 3 (20:80). The total run time was 4 min and after optimization of UHPLC-MS/MS-parameters validation included selectivity, matrix effects, recovery, process efficiency, calibration model and range, lower limit of quantification, precision and bias. The calibration curve ranged from 0.02 to 12.5 ng/mg, and the recovery was between 62 and 83%. During validation the bias was less than ±7% and the imprecision was less than 5% for all analytes. In routine analysis, fortified control samples demonstrated an imprecision <13% and control samples made from authentic hair demonstrated an imprecision <26%. The method was applied to samples from a controlled study of amphetamine intake as well as forensic hair samples previously analyzed with an ultra high performance liquid chromatography time of flight mass spectrometry (UHPLC-TOF-MS) screening method. The proposed method was suitable for quantification of these drugs in forensic cases including violent crimes, autopsy cases, drug testing and re-granting of driving licences. This study also demonstrated that if hair samples are divided into several short segments, the time point for intake of a small dose of amphetamine can be estimated, which might be useful when drug facilitated crimes are investigated. Copyright © 2014 John Wiley & Sons, Ltd.

LC-MS/MS suggests that hole hopping in cytochrome c peroxidase protects its heme from oxidative modification by excess H2O2.

Science.gov (United States)

Kathiresan, Meena; English, Ann M

2017-02-01

We recently reported that cytochrome c peroxidase (Ccp1) functions as a H 2 O 2 sensor protein when H 2 O 2 levels rise in respiring yeast. The availability of its reducing substrate, ferrocytochrome c (Cyc II ), determines whether Ccp1 acts as a H 2 O 2 sensor or peroxidase. For H 2 O 2 to serve as a signal it must modify its receptor so we employed high-performance LC-MS/MS to investigate in detail the oxidation of Ccp1 by 1, 5 and 10 M eq. of H 2 O 2 in the absence of Cyc II to prevent peroxidase activity. We observe strictly heme-mediated oxidation, implicating sequential cycles of binding and reduction of H 2 O 2 at Ccp1's heme. This results in the incorporation of ∼20 oxygen atoms predominantly at methionine and tryptophan residues. Extensive intramolecular dityrosine crosslinking involving neighboring residues was uncovered by LC-MS/MS sequencing of the crosslinked peptides. The proximal heme ligand, H175, is converted to oxo-histidine, which labilizes the heme but irreversible heme oxidation is avoided by hole hopping to the polypeptide until oxidation of the catalytic distal H52 in Ccp1 treated with 10 M eq. of H 2 O 2 shuts down heterolytic cleavage of H 2 O 2 at the heme. Mapping of the 24 oxidized residues in Ccp1 reveals that hole hopping from the heme is directed to three polypeptide zones rich in redox-active residues. This unprecedented analysis unveils the remarkable capacity of a polypeptide to direct hole hopping away from its active site, consistent with heme labilization being a key outcome of Ccp1-mediated H 2 O 2 signaling. LC-MS/MS identification of the oxidized residues also exposes the bias of electron paramagnetic resonance (EPR) detection toward transient radicals with low O 2 reactivity.

Optimization of the Extraction of the Volatile Fraction from Honey Samples by SPME-GC-MS, Experimental Design, and Multivariate Target Functions

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Elisa Robotti

2017-01-01

Full Text Available Head space (HS solid phase microextraction (SPME followed by gas chromatography with mass spectrometry detection (GC-MS is the most widespread technique to study the volatile profile of honey samples. In this paper, the experimental SPME conditions were optimized by a multivariate strategy. Both sensitivity and repeatability were optimized by experimental design techniques considering three factors: extraction temperature (from 50°C to 70°C, time of exposition of the fiber (from 20 min to 60 min, and amount of salt added (from 0 to 27.50%. Each experiment was evaluated by Principal Component Analysis (PCA that allows to take into consideration all the analytes at the same time, preserving the information about their different characteristics. Optimal extraction conditions were identified independently for signal intensity (extraction temperature: 70°C; extraction time: 60 min; salt percentage: 27.50% w/w and repeatability (extraction temperature: 50°C; extraction time: 60 min; salt percentage: 27.50% w/w and a final global compromise (extraction temperature: 70°C; extraction time: 60 min; salt percentage: 27.50% w/w was also reached. Considerations about the choice of the best internal standards were also drawn. The whole optimized procedure was than applied to the analysis of a multiflower honey sample and more than 100 compounds were identified.

Particle swarm optimization: an alternative in marine propeller optimization?

Science.gov (United States)

Vesting, F.; Bensow, R. E.

2018-01-01

This article deals with improving and evaluating the performance of two evolutionary algorithm approaches for automated engineering design optimization. Here a marine propeller design with constraints on cavitation nuisance is the intended application. For this purpose, the particle swarm optimization (PSO) algorithm is adapted for multi-objective optimization and constraint handling for use in propeller design. Three PSO algorithms are developed and tested for the optimization of four commercial propeller designs for different ship types. The results are evaluated by interrogating the generation medians and the Pareto front development. The same propellers are also optimized utilizing the well established NSGA-II genetic algorithm to provide benchmark results. The authors' PSO algorithms deliver comparable results to NSGA-II, but converge earlier and enhance the solution in terms of constraints violation.

Determination of 4-Methylimidazole in Ammonia Caramel Using Gas Chromatography–Tandem Mass Spectrometry (GC-MS/MS

Directory of Open Access Journals (Sweden)

Martyna N. Wieczorek

2018-01-01

Full Text Available One of Maillard reaction products formed in the production of ammonia caramel is 4(5-methylimidazole (4-MeI classified as carcinogen. A method of 4-MeI determination based on ion-pair extraction and derivatisation with isobutyl chloroformate with subsequent gas chromatography-tandem mass spectrometry analysis was proposed. Tandem mass spectrometry was applied to reduce the influence of matrix and increase the selectivity and sensitivity of the method. Triple quadrupole GC-MS system was used for this study. The collision energies were optimized for MRM mode. The detection (LOD and quantification limits (LOQ of the elaborated method were 17 and 37.8 μg kg−1, respectively, repeatability was <15% RSD for analyzed caramel samples, and the recovery for 4-MeI was 101%. Comparison of MS/MS with SIM detection on the same instrument proved almost 30 times lower LODs achieved by tandem mass spectrometry compared to SIM. Described method can be routinely used for monitoring 4-MeI as a quality and safety marker in the production of ammonia caramel.

Pediatric MS

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... Pediatric MS Share this page Facebook Twitter Email Pediatric MS Pediatric MS Pediatric MS Support Pediatric Providers ... system through the Pediatric MS Support Group . Treating pediatric MS In 2018 the U.S. Food and Drug ...

Optimization of agrobacterium tumefaciens mediated transformation in eucalyptus camaldulensis

International Nuclear Information System (INIS)

Ahad, A.; Maqbool, A.; Malik, K.A.

2014-01-01

This study was conducted to optimize Agrobacterium tumefaciens mediated transformation for Eucalyptus camaldulensis. Transformation was done by using LBA4404 containing binary plasmid pGA482 with uidA (Gus) gene under CamV35S promoter and nptII gene under nos promoter. For optimization, different explants (Cotyledonary leaves, plantlet leaves and hypocotyls of young In vitro plants and calli) with and without preculture were infected with a range of optical densities (O.D.600nm=0.3-0.6). Effect of different concentrations of Acetosyringone, infection time and co-cultivation time on transformation efficiency was evaluated. Confirmation of transformation was done through GUS histochemical staining and through PCR. Callogenesis and regeneration was found fast on MS medium containing 0.5 mg/L NAA and 1.5 mg/L BAP. Highest transformation efficiency was obtained with bacterial suspension of O.D.600nm = 0.5 for non-precultured explants and O.D.600nm=0.3 for precultured explants. (author)

UPLC-MS/MS determination of ptaquiloside and pterosin B in preserved natural water.

Science.gov (United States)

Clauson-Kaas, Frederik; Hansen, Hans Christian Bruun; Strobel, Bjarne W

2016-11-01

The naturally occurring carcinogen ptaquiloside and its degradation product pterosin B are found in water leaching from bracken stands. The objective of this work is to present a new sample preservation method and a fast UPLC-MS/MS method for quantification of ptaquiloside and pterosin B in environmental water samples, employing a novel internal standard. A faster, reliable, and efficient method was developed for isolation of high purity ptaquiloside and pterosin B from plant material for use as analytical standards, with purity verified by 1 H-NMR. The chemical analysis was performed by cleanup and preconcentration of samples with solid phase extraction, before analyte quantification with UPLC-MS/MS. By including gradient elution and optimizing the liquid chromatography mobile phase buffer system, a total run cycle of 5 min was achieved, with method detection limits, including preconcentration, of 8 and 4 ng/L for ptaquiloside and pterosin B, respectively. The use of loganin as internal standard improved repeatability of the determination of both analytes, though it could not be employed for sample preparation. Buffering raw water samples in situ with ammonium acetate to pH ∼5.5 decisively increased sample integrity at realistic transportation and storing conditions prior to extraction. Groundwater samples collected in November 2015 at the shallow water table below a Danish bracken stand were preserved and analyzed using the above methods, and PTA concentrations of 3.8 ± 0.24 μg/L (±sd, n = 3) were found, much higher than previously reported. Graphical abstract Workflow overview of ptaquiloside determination.

SprayQc: a real-time LC-MS/MS quality monitoring system to maximize uptime using off the shelf components.

Science.gov (United States)

Scheltema, Richard A; Mann, Matthias

2012-06-01

With the advent of high-throughput mass spectrometry (MS)-based proteomics, the magnitude and complexity of the performed experiments has increased dramatically. Likewise, investments in chromatographic and MS instrumentation are a large proportion of the budget of proteomics laboratories. Guarding measurement quality and maximizing uptime of the LC-MS/MS systems therefore requires constant care despite automated workflows. We describe a real-time surveillance system, called SprayQc, that continuously monitors the status of the peripheral equipment to ensure that operational parameters are within an acceptable range. SprayQc is composed of multiple plug-in software components that use computer vision to analyze electrospray conditions, monitor the chromatographic device for stable backpressure, interact with a column oven to control pressure by temperature, and ensure that the mass spectrometer is still acquiring data. Action is taken when a failure condition has been detected, such as stopping the column oven and the LC flow, as well as automatically notifying the appropriate operator. Additionally, all defined metrics can be recorded synchronized on retention time with the MS acquisition file, allowing for later inspection and providing valuable information for optimization. SprayQc has been extensively tested in our laboratory, supports third-party plug-in development, and is freely available for download from http://sourceforge.org/projects/sprayqc .

Optimization of simultaneous electrochemical determination of Cd(II), Pb(II), Cu(II) and Hg(II) at carbon nanotube-modified graphite electrodes.

Science.gov (United States)

Pikna, L'ubomír; Heželová, Mária; Kováčová, Zuzana

2015-01-01

The health of the environment is worsening every day. Monitoring of potentially toxic elements and remediation of environmental pollution are necessary. Therefore, the research and development of simple, inexpensive, portable and effective sensors is important. Electrochemistry is a useful component of the field of environment monitoring. The present study focuses on evaluating and comparing three types of electrodes (PIGE, PIGE/MWCNT/HNO3 and PIGE/MWCNT/EDTA/HNO3) employed for the simultaneous electrochemical determination of four potentially toxic elements: Cd(II), Pb(II), Cu(II) and Hg(II). Cyclic voltammograms were measured in an acetate buffer. The LOD, LOQ, the standard and relative precisions of the method and a prediction intervals were calculated (according to the technical procedure DIN 32 645) for the three electrodes and for each measured element. The LOD for PIGE/CNT/HNO3 (the electrode with narrowest calculated prediction intervals) was 2.98 × 10(-7) mol L(-1) for Cd(II), 4.83 × 10(-7) mol L(-1) for Pb(II), 3.81 × 10(-7) mol L(-1) for Cu(II), 6.79 × 10(-7) mol L(-1) for Hg(II). One of the benefits of this study was the determination of the amount of Hg(II) in the mixture of other elements.

Ultra high performance supercritical fluid chromatography coupled with tandem mass spectrometry for screening of doping agents. I: Investigation of mobile phase and MS conditions.

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Nováková, Lucie; Grand-Guillaume Perrenoud, Alexandre; Nicoli, Raul; Saugy, Martial; Veuthey, Jean-Luc; Guillarme, Davy

2015-01-01

The conditions for the analysis of selected doping substances by UHPSFC-MS/MS were optimized to ensure suitable peak shapes and maximized MS responses. A representative mixture of 31 acidic and basic doping agents was analyzed, in both ESI+ and ESI- modes. The best compromise for all compounds in terms of MS sensitivity and chromatographic performance was obtained when adding 2% water and 10mM ammonium formate in the CO2/MeOH mobile phase. Beside mobile phase, the nature of the make-up solvent added for interfacing UHPSFC with MS was also evaluated. Ethanol was found to be the best candidate as it was able to compensate for the negative effect of 2% water addition in ESI- mode and provided a suitable MS response for all doping agents. Sensitivity of the optimized UHPSFC-MS/MS method was finally assessed and compared to the results obtained in conventional UHPLC-MS/MS. Sensitivity was improved by 5-100-fold in UHPSFC-MS/MS vs. UHPLC-MS/MS for 56% of compounds, while only one compound (bumetanide) offered a significantly higher MS response (4-fold) under UHPLC-MS/MS conditions. In the second paper of this series, the optimal conditions for UHPSFC-MS/MS analysis will be employed to screen >100 doping agents in urine matrix and results will be compared to those obtained by conventional UHPLC-MS/MS. Copyright © 2014 Elsevier B.V. All rights reserved.

BOP2: Bayesian optimal design for phase II clinical trials with simple and complex endpoints.

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Zhou, Heng; Lee, J Jack; Yuan, Ying

2017-09-20

We propose a flexible Bayesian optimal phase II (BOP2) design that is capable of handling simple (e.g., binary) and complicated (e.g., ordinal, nested, and co-primary) endpoints under a unified framework. We use a Dirichlet-multinomial model to accommodate different types of endpoints. At each interim, the go/no-go decision is made by evaluating a set of posterior probabilities of the events of interest, which is optimized to maximize power or minimize the number of patients under the null hypothesis. Unlike other existing Bayesian designs, the BOP2 design explicitly controls the type I error rate, thereby bridging the gap between Bayesian designs and frequentist designs. In addition, the stopping boundary of the BOP2 design can be enumerated prior to the onset of the trial. These features make the BOP2 design accessible to a wide range of users and regulatory agencies and particularly easy to implement in practice. Simulation studies show that the BOP2 design has favorable operating characteristics with higher power and lower risk of incorrectly terminating the trial than some existing Bayesian phase II designs. The software to implement the BOP2 design is freely available at www.trialdesign.org. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Optimal Control and Optimization of Stochastic Supply Chain Systems

CERN Document Server

Song, Dong-Ping

2013-01-01

Optimal Control and Optimization of Stochastic Supply Chain Systems examines its subject in the context of the presence of a variety of uncertainties. Numerous examples with intuitive illustrations and tables are provided, to demonstrate the structural characteristics of the optimal control policies in various stochastic supply chains and to show how to make use of these characteristics to construct easy-to-operate sub-optimal policies.                 In Part I, a general introduction to stochastic supply chain systems is provided. Analytical models for various stochastic supply chain systems are formulated and analysed in Part II. In Part III the structural knowledge of the optimal control policies obtained in Part II is utilized to construct easy-to-operate sub-optimal control policies for various stochastic supply chain systems accordingly. Finally, Part IV discusses the optimisation of threshold-type control policies and their robustness. A key feature of the book is its tying together of ...

UPLC-qTOF-MS profiling of pharmacologically important chlorogenic acids and associated glycosides in Moringa ovalifolia leaf extracts

CSIR Research Space (South Africa)

Makita, C

2017-01-01

Full Text Available been shown to be effective natural remedies for the management of chronic ailments such as diabetes and cardiovascular diseases. Using a UPLC-ISCID-MS/MS method optimized to mimic the MSn fragmentation of an ion trap-based MS but generating accurate...

Optimized LC-MS/MS Method for the High-throughput Analysis of Clinical Samples of Ivacaftor, Its Major Metabolites, and Lumacaftor in Biological Fluids of Cystic Fibrosis Patients.

Science.gov (United States)

Schneider, Elena K; Reyes-Ortega, Felisa; Li, Jian; Velkov, Tony

2017-10-15

Defects in the cystic fibrosis trans-membrane conductance regulator (CFTR) are the cause of cystic fibrosis (CF), a disease with life-threatening pulmonary manifestations. Ivacaftor (IVA) and ivacaftor-lumacaftor (LUMA) combination are two new breakthrough CF drugs that directly modulate the activity and trafficking of the defective CFTR-protein. However, there is still a dearth of understanding on pharmacokinetic/pharmacodynamic parameters and the pharmacology of ivacaftor and lumacaftor. The HPLC-MS technique for the simultaneous analysis of the concentrations of ivacaftor, hydroxymethyl-ivacaftor, ivacaftor-carboxylate, and lumacaftor in biological fluids in patients receiving standard ivacaftor or ivacaftor-lumacaftor combination therapy has previously been developed by our group and partially validated to FDA standards. However, to allow the high-throughput analysis of a larger number of patient samples, our group has optimized the reported method through the use of a smaller pore size reverse-phase chromatography column (2.6 µm, C8 100 Å; 50 x 2.1 mm) and a gradient solvent system (0-1 min: 40% B; 1-2 min: 40-70% B; 2-2.7 min: held at 70% B; 2.7-2.8 min: 70-90% B; 2.8-4.0 min: 90% B washing; 4.0-4.1 min: 90-40% B; 4.1-6.0 min: held at 40% B) instead of an isocratic elution. The goal of this study was to reduce the HPLC-MS analysis time per sample dramatically from ~15 min to only 6 min per sample, which is essential for the analysis of a large amount of patient samples. This expedient method will be of considerable utility for studies into the exposure-response relationships of these breakthrough CF drugs.

A multi-center ring trial for the identification of anaerobic bacteria using MALDI-TOF MS.

Science.gov (United States)

Veloo, A C M; Jean-Pierre, H; Justesen, U S; Morris, T; Urban, E; Wybo, I; Shah, H N; Friedrich, A W; Morris, T; Shah, H N; Jean-Pierre, H; Justesen, U S; Nagy, E; Urban, E; Kostrzewa, M; Veloo, A; Friedrich, A W

2017-12-01

Inter-laboratory reproducibility of Matrix Assisted Laser Desorption Time-of-Flight Mass Spectrometry (MALDI-TOF MS) of anaerobic bacteria has not been shown before. Therefore, ten anonymized anaerobic strains were sent to seven participating laboratories, an initiative of the European Network for the Rapid Identification of Anaerobes (ENRIA). On arrival the strains were cultured and identified using MALDI-TOF MS. The spectra derived were compared with two different Biotyper MALDI-TOF MS databases, the db5627 and the db6903. The results obtained using the db5627 shows a reasonable variation between the different laboratories. However, when a more optimized database is used, the variation is less pronounced. In this study we show that an optimized database not only results in a higher number of strains which can be identified using MALDI-TOF MS, but also corrects for differences in performance between laboratories. Copyright © 2017 Elsevier Ltd. All rights reserved.

Simultaneous analysis of multiple classes of antimicrobials in environmental water samples using SPE coupled with UHPLC-ESI-MS/MS and isotope dilution.

Science.gov (United States)

Tran, Ngoc Han; Chen, Hongjie; Do, Thanh Van; Reinhard, Martin; Ngo, Huu Hao; He, Yiliang; Gin, Karina Yew-Hoong

2016-10-01

A robust and sensitive analytical method was developed for the simultaneous analysis of 21 target antimicrobials in different environmental water samples. Both single SPE and tandem SPE cartridge systems were investigated to simultaneously extract multiple classes of antimicrobials. Experimental results showed that good extraction efficiencies (84.5-105.6%) were observed for the vast majority of the target analytes when extraction was performed using the tandem SPE cartridge (SB+HR-X) system under an extraction pH of 3.0. HPLC-MS/MS parameters were optimized for simultaneous analysis of all the target analytes in a single injection. Quantification of target antimicrobials in water samples was accomplished using 15 isotopically labeled internal standards (ILISs), which allowed the efficient compensation of the losses of target analytes during sample preparation and correction of matrix effects during UHPLC-MS/MS as well as instrument fluctuations in MS/MS signal intensity. Method quantification limit (MQL) for most target analytes based on SPE was below 5ng/L for surface waters, 10ng/L for treated wastewater effluents, and 15ng/L for raw wastewater. The method was successfully applied to detect and quantify the occurrence of the target analytes in raw influent, treated effluent and surface water samples. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of Flavonoids in Lotus (Nelumbo nucifera Leaves and Their Antioxidant Activity Using Macroporous Resin Chromatography Coupled with LC-MS/MS and Antioxidant Biochemical Assays

Directory of Open Access Journals (Sweden)

Ming-Zhi Zhu

2015-06-01

Full Text Available Lotus (Nelumbo nucifera leaves, a traditional Chinese medicinal herb, are rich in flavonoids. In an effort to thoroughly analyze their flavonoid components, macroporous resin chromatography coupled with HPLC-MS/MS was employed to simultaneously enrich and identify flavonoids from lotus leaves. Flavonoids extracted from lotus leaves were selectively enriched in the macroporous resin column, eluted subsequently as fraction II, and successively subjected to analysis with the HPLC-MS/MS and bioactivity assays. Altogether, fourteen flavonoids were identified, four of which were identified from lotus leaves for the first time, including quercetin 3-O-rhamnopyranosyl-(1→2-glucopyranoside, quercetin 3-O-arabinoside, diosmetin 7-O-hexose, and isorhamnetin 3-O-arabino- pyranosyl-(1→2-glucopyranoside. Further bioactivity assays revealed that these flavonoids from lotus leaves possess strong antioxidant activity, and demonstrate very good potential to be explored as food supplements or even pharmaceutical products to improve human health.

Quantification of the Triazole Antifungal Compounds Voriconazole and Posaconazole in Human Serum or Plasma Using Liquid Chromatography Electrospray Tandem Mass Spectrometry (HPLC-ESI-MS/MS).

Science.gov (United States)

Molinelli, Alejandro R; Rose, Charles H

2016-01-01

Voriconazole and posaconazole are triazole antifungal compounds used in the treatment of fungal infections. Therapeutic drug monitoring of both compounds is recommended in order to guide drug dosing to achieve optimal blood concentrations. In this chapter we describe an HPLC-ESI-MS/MS method for the quantification of both compounds in human plasma or serum following a simple specimen preparation procedure. Specimen preparation consists of protein precipitation using methanol and acetonitrile followed by a cleanup step that involves filtration through a cellulose acetate membrane. The specimen is then injected into an HPLC-ESI-MS/MS equipped with a C18 column and separated over an acetonitrile gradient. Quantification of the drugs in the specimen is achieved by comparing the response of the unknown specimen to that of the calibrators in the standard curve using multiple reaction monitoring.

Optimization of the HS-SPME-GC/MS technique for the analysis of volatile compounds in caprine Coalho cheese using response surface methodology

Directory of Open Access Journals (Sweden)

Taliana Kênia Alves BEZERRA

2016-03-01

Full Text Available Abstract Caprine Coalho cheese presents great potential for a typical protected designation of origin, considering that this traditional Brazilian cheese presents a slightly salty and acid flavor, combined with a unique texture. This study optimized the HS-SPME-GC-MS methodology for volatile analysis of Coalho cheese, which can be used as a tool to help in the identification of the distinctive aroma profile of this cheese. The conditions of equilibrium time, extraction temperature and time were optimized using the statistical tool factorial experimental design 23, and applying the desirability function. After the evaluation, it was concluded that the optimum extraction conditions comprised equilibrium and extraction time of 20 and 40 minutes, respectively; and ideal extraction temperature of 45 °C. The optimum extraction of volatile compounds in goat Coalho cheese captured 32 volatile compounds: 5 alcohols, 5 esters, 3 ketones, 6 acids, 3 aldehydes, 3 terpenes, and 7 hydrocarbons.

LC-MS/MS analysis of uncommon paracetamol metabolites derived through in vitro polymerization and nitration reactions in liquid nitrogen.

Science.gov (United States)

Trettin, Arne; Jordan, Jens; Tsikas, Dimitrios

2014-09-01

Paracetamol (acetaminophen, APAP) is a commonly used analgesic drug. Known paracetamol metabolites include the glucuronide, sulfate and mercapturate. N-Acetyl-benzoquinonimine (NAPQI) is considered the toxic intermediate metabolite of paracetamol. In vitro and in vivo studies indicate that paracetamol is also metabolized to additional poorly characterized metabolites. For example, metabolomic studies in urine samples of APAP-treated mice revealed metabolites such as APAP-sulfate-APAP and APAP-S-S-APAP in addition to the classical phase II metabolites. Here, we report on the development and application of LC-MS and LC-MS/MS approaches to study reactions of unlabelled and (2)H-labelled APAP with unlabelled and (15)N-labelled nitrite in aqueous phosphate buffers (pH 7.4) upon their immersion into liquid nitrogen (-196°C). In mechanistic studies, these reactions were also studied in aqueous buffer prepared in (18)O-labelled water. LC-MS and LC-MS/MS analyses were performed on a reverse-phase material (C18) using gradient elution (2mM ammonium acetate/acetonitrile), in positive and negative electrospray mode. We identified a series of APAP metabolites including di-, tri- and tetra-APAP, mono- and di-nitro-APAP and nitric ester of di-APAP. Our study indicates that nitrite induces oxidation, i.e., polymerization and nitration of APAP, when buffered APAP/nitrite solutions are immersed into liquid nitrogen. These reactions are specific for nitrite with respect to nitrate and do not proceed via intermediate formation of NAPQI. Potassium ions and physiological saline but not thiols inhibit nitrite- and shock-freeze-induced reactions of paracetamol. The underlying mechanism likely involves in situ formation of NO2 radicals from nitrite secondary to profound pH reduction (down to pH 1) and disproportionation. Polymeric paracetamol species can be analyzed as pentafluorobenzyl derivatives by LC-MS but not by GC-MS. Copyright © 2013 Elsevier B.V. All rights reserved.

Reliability Of A Novel Intracardiac Electrogram Method For AV And VV Delay Optimization And Comparability To Echocardiography Procedure For Determining Optimal Conduction Delays In CRT Patients

Directory of Open Access Journals (Sweden)

N Reinsch

2009-03-01

Full Text Available Background: Echocardiography is widely used to optimize CRT programming. A novel intracardiac electrogram method (IEGM was recently developed as an automated programmer-based method, designed to calculate optimal atrioventricular (AV and interventricular (VV delays and provide optimized delay values as an alternative to standard echocardiographic assessment.Objective: This study was aimed at determining the reliability of this new method. Furthermore the comparability of IEGM to existing echocardiographic parameters for determining optimal conduction delays was verified.Methods: Eleven patients (age 62.9± 8.7; 81% male; 73% ischemic, previously implanted with a cardiac resynchronisation therapy defibrillator (CRT-D underwent both echocardiographic and IEGM-based delay optimization.Results: Applying the IEGM method, concordance of three consecutively performed measurements was found in 3 (27% patients for AV delay and in 5 (45% patients for VV delay. Intra-individual variation between three measurements as assessed by the IEGM technique was up to 20 ms (AV: n=6; VV: n=4. E-wave, diastolic filling time and septal-to-lateral wall motion delay emerged as significantly different between the echo and IEGM optimization techniques (p < 0.05. The final AV delay setting was significantly different between both methods (echo: 126.4 ± 29.4 ms, IEGM: 183.6 ± 16.3 ms; p < 0.001; correlation: R = 0.573, p = 0.066. VV delay showed significant differences for optimized delays (echo: 46.4 ± 23.8 ms, IEGM: 10.9 ± 7.0 ms; p <0.01; correlation: R = -0.278, p = 0.407.Conclusion: The automated programmer-based IEGM-based method provides a simple and safe method to perform CRT optimization. However, the reliability of this method appears to be limited. Thus, it remains difficult for the examiner to determine the optimal hemodynamic settings. Additionally, as there was no correlation between the optimal AV- and VV-delays calculated by the IEGM method and the echo

Dansyl-peptides matrix-assisted laser desorption/ionization mass spectrometric (MALDI-MS) and tandem mass spectrometric (MS/MS) features improve the liquid chromatography/MALDI-MS/MS analysis of the proteome.

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Chiappetta, Giovanni; Ndiaye, Sega; Demey, Emmanuelle; Haddad, Iman; Marino, Gennaro; Amoresano, Angela; Vinh, Joëlle

2010-10-30

Peptide tagging is a useful tool to improve matrix-assisted laser desorption/ionization tandem mass spectrometric (MALDI-MS/MS) analysis. We present a new application of the use of the dansyl chloride (DNS-Cl). DNS-Cl is a specific primary amine reagent widely used in protein biochemistry. It adds a fluorescent dimethylaminonaphthalene moiety to the molecule. The evaluation of MALDI-MS and MS/MS analyses of dansylated peptides shows that dansylation raises the ionization efficiency of the most hydrophilic species compared with the most hydrophobic ones. Consequently, higher Mascot scores and protein sequence coverage are obtained by combining MS and MS/MS data of native and tagged samples. The N-terminal DNS-Cl sulfonation improves the peptide fragmentation and promotes the generation of b-fragments allowing better peptide sequencing. In addition, we set up a labeling protocol based on the microwave chemistry. Peptide dansylation proved to be a rapid and cheap method to improve the performance of liquid chromatography (LC)/MALDI-MS/MS analysis at the proteomic scale in terms of peptide detection and sequence coverage. Copyright © 2010 John Wiley & Sons, Ltd.

Set-Based Discrete Particle Swarm Optimization Based on Decomposition for Permutation-Based Multiobjective Combinatorial Optimization Problems.

Science.gov (United States)

Yu, Xue; Chen, Wei-Neng; Gu, Tianlong; Zhang, Huaxiang; Yuan, Huaqiang; Kwong, Sam; Zhang, Jun

2017-08-07

This paper studies a specific class of multiobjective combinatorial optimization problems (MOCOPs), namely the permutation-based MOCOPs. Many commonly seen MOCOPs, e.g., multiobjective traveling salesman problem (MOTSP), multiobjective project scheduling problem (MOPSP), belong to this problem class and they can be very different. However, as the permutation-based MOCOPs share the inherent similarity that the structure of their search space is usually in the shape of a permutation tree, this paper proposes a generic multiobjective set-based particle swarm optimization methodology based on decomposition, termed MS-PSO/D. In order to coordinate with the property of permutation-based MOCOPs, MS-PSO/D utilizes an element-based representation and a constructive approach. Through this, feasible solutions under constraints can be generated step by step following the permutation-tree-shaped structure. And problem-related heuristic information is introduced in the constructive approach for efficiency. In order to address the multiobjective optimization issues, the decomposition strategy is employed, in which the problem is converted into multiple single-objective subproblems according to a set of weight vectors. Besides, a flexible mechanism for diversity control is provided in MS-PSO/D. Extensive experiments have been conducted to study MS-PSO/D on two permutation-based MOCOPs, namely the MOTSP and the MOPSP. Experimental results validate that the proposed methodology is promising.

A method of coupling the Paternò-Büchi reaction with direct infusion ESI-MS/MS for locating the C[double bond, length as m-dash]C bond in glycerophospholipids.

Science.gov (United States)

Stinson, Craig A; Xia, Yu

2016-06-21

Tandem mass spectrometry (MS/MS) coupled with soft ionization is established as an essential platform for lipid analysis; however, determining high order structural information, such as the carbon-carbon double bond (C[double bond, length as m-dash]C) location, remains challenging. Recently, our group demonstrated a method for sensitive and confident lipid C[double bond, length as m-dash]C location determination by coupling online the Paternò-Büchi (PB) reaction with nanoelectrospray ionization (nanoESI) and MS/MS. Herein, we aimed to expand the scope of the PB reaction for lipid analysis by enabling the reaction with infusion ESI-MS/MS at much higher flow rates than demonstrated in the nanoESI setup (∼20 nL min(-1)). In the new design, the PB reaction was effected in a fused silica capillary solution transfer line, which also served as a microflow UV reactor, prior to ESI. This setup allowed PB reaction optimization and kinetics studies. Under optimized conditions, a maximum of 50% PB reaction yield could be achieved for a standard glycerophosphocholine (PC) within 6 s of UV exposure over a wide flow rate range (0.1-10 μL min(-1)). A solvent composition of 7 : 3 acetone : H2O (with 1% acid or base modifier) allowed the highest PB yields and good lipid ionization, while lower yields were obtained with an addition of a variety of organic solvents. Radical induced lipid peroxidation was identified to induce undesirable side reactions, which could be effectively suppressed by eliminating trace oxygen in the solution via N2 purge. Finally, the utility of coupling the PB reaction with infusion ESI-MS/MS was demonstrated by analyzing a yeast polar lipid extract where C[double bond, length as m-dash]C bond locations were revealed for 35 glycerophospholipids (GPs).

Analysis of aquatic-phase natural organic matter by optimized LDI-MS method

KAUST Repository

Wang, Renqi; Druckenmü ller, Katharina; Elbers, Gereon; Guenther, Klaus; Croue, Jean-Philippe

2014-01-01

. On the other hand, the waste water and reservoir water mainly had relatively smaller molecules of about 2000 Da. The LDI-MS measurements indicated that highly humic river waters were able to form large aggregates and membrane foulants, while the HPO NOMs from

Facilitating the Hyphenation of CIEF and MALDI-MS for Two-Dimensional Separation of Proteins

Science.gov (United States)

Cheng, Chang; Lu, Joann J.; Wang, Xiayan; Roberts, Jonathan; Liu, Shaorong

2011-01-01

Both CIEF and MALDI-MS are frequently used in protein analysis, but hyphenation of the two is not investigated proportionally. One of the major reasons is that the additives (such as carrier ampholytes and detergent) in CIEF severely suppress the MALDI-MS signal, which hampers the hyphenation of the two. In this paper, we develop a simple means to alleviate the above signal-suppressing effect. We first deposit 1 µL of water onto a MALDI-MS target, deliver a fraction of CIEF-separated protein (~0.1 µL) to the water droplet, evaporate the solvent, add 0.5 µL of MALDI matrix to the sample spot, dry the matrix, and move the target plate to a MALDI-TOF-MS for mass spectrum measurement. We optimize the droplet volume and the laser-ablation region. Under the optimized conditions, we improve the signal to noise ratio by 2–10 fold. We also apply this method for two-dimensional separations of standard proteins and Apolipoprotein A-I, a membrane protein expressed in E. Coli cells. PMID:20603827

Determination of Urinary PAH Metabolites Using DLLME Hyphenated to Injector Port Silylation and GC-MS-MS.

Science.gov (United States)

Gupta, Manoj Kumar; Jain, Rajeev; Singh, Pratibha; Ch, Ratnasekhar; Mudiam, Mohana Krishna Reddy

2015-06-01

Polycyclic aromatic hydrocarbons (PAHs) are ubiquitous environmental pollutants and well-known carcinogens. Hydroxy derivatives of PAH are considered as biomarkers of PAH exposure, and there is a need to measure these metabolites at low concentrations. So, a precise and eco-friendly analytical method has been developed for rapid determination of PAH metabolites. For the first time, a new analytical method based on coupling of dispersive liquid-liquid microextraction (DLLME) with auto-injector port silylation (auto-IPS) followed by gas chromatography-tandem mass spectrometry (GC-MS-MS) analysis is reported for the analysis of seven urinary PAH metabolites. Factors affecting DLLME and IPS, such as type and volume of extraction and disperser solvent, pH, ionic strength, injector port temperature, volume of N,O-bis(trimethylsilyl)trifluoroacetamide and type of solvent were investigated. Under optimized conditions, the limit of detection and limit of quantification were found to be in the range of 1-9 and 3-29 ng/mL, respectively. Satisfactory recoveries of metabolites in urine samples in the range of 87-95% were found. The developed method has been successfully applied for the determination of PAH metabolites in urine samples of exposed workers. DLLME-auto-IPS-GC-MS-MS method is time, labor, solvent and reagent saving, which can be routinely used for the analysis of urinary PAH metabolites. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

MALDI-TOF MS/MS measurements of PMMA

NARCIS (Netherlands)

Becer, C.R.; Baumgaertel, A.; Gottschaldt, M.; Schubert, U.S.

2008-01-01

The polymer poly(Me methacrylate) (PMMA) was analyzed using the matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) technique. The MALDI-TOF MS app. was coupled with a collision-induced dissocn. (CID) unit. The performance of the MALDI-TOF/TOF MS method in

Gas chromatography-mass spectrometry (GC-MS) and liquid chromatography-mass spectrometry (LC-MS) in toxicological analysis. Studies on the detection of clobenzorex and its metabolites within a systematic toxicological analysis procedure by GC-MS and by immunoassay and studies on the detection of alpha- and beta-amanitin in urine by atmospheric pressure ionization electrospray LC-MS.

Science.gov (United States)

Maurer, H H; Kraemer, T; Ledvinka, O; Schmitt, C J; Weber, A A

1997-02-07

GC-MS is the method of choice for toxicological analysis of toxicants volatile in GC while non-volatile and/or thermally labile toxicants need LC-MS for their determination. Studies are presented on the toxicological detection of the amphetamine-like anorectic clobenzorex in urine by GC-MS after acid hydrolysis, extraction and acetylation and by fluorescence polarization immunoassay (FPIA, TDx (meth)amphetamine II). After ingestion of 60 mg of clobenzorex, the parent compound and/or its metabolites could be detected by GC-MS for up to 84 h or by FPIA for up to 60 h. Since clobenzorex shows no cross-reactivity with the used immunoassay, the N-dealkylated metabolite amphetamine is responsible for the positive TDx results. The intake of clobenzorex instead of amphetamine can be differentiated by GC-MS detection of hydroxyclobenzorex which is detectable for at least as long as amphetamine. In addition, the described GC-MS procedure allows the simultaneous detection of most of the toxicologically relevant drugs. Furthermore, studies are described on the atmospheric pressure ionization electrospray LC-MS detection of alpha- and beta-amanitin, toxic peptides of amanita mushrooms, in urine after solid-phase extraction on RP-18 columns. Using the single ion monitoring mode with the ions m/z 919 and 920 the amanitins could be detected down to 10 ng/ml of urine which allows us to diagnose intoxications with amanita mushrooms.

Importance of optimizing chromatographic conditions and mass spectrometric parameters for supercritical fluid chromatography/mass spectrometry.

Science.gov (United States)

Fujito, Yuka; Hayakawa, Yoshihiro; Izumi, Yoshihiro; Bamba, Takeshi

2017-07-28

Supercritical fluid chromatography/mass spectrometry (SFC/MS) has great potential in high-throughput and the simultaneous analysis of a wide variety of compounds, and it has been widely used in recent years. The use of MS for detection provides the advantages of high sensitivity and high selectivity. However, the sensitivity of MS detection depends on the chromatographic conditions and MS parameters. Thus, optimization of MS parameters corresponding to the SFC condition is mandatory for maximizing performance when connecting SFC to MS. The aim of this study was to reveal a way to decide the optimum composition of the mobile phase and the flow rate of the make-up solvent for MS detection in a wide range of compounds. Additionally, we also showed the basic concept for determination of the optimum values of the MS parameters focusing on the MS detection sensitivity in SFC/MS analysis. To verify the versatility of these findings, a total of 441 pesticides with a wide polarity range (logP ow from -4.21 to 7.70) and pKa (acidic, neutral and basic). In this study, a new SFC-MS interface was used, which can transfer the entire volume of eluate into the MS by directly coupling the SFC with the MS. This enabled us to compare the sensitivity or optimum MS parameters for MS detection between LC/MS and SFC/MS for the same sample volume introduced into the MS. As a result, it was found that the optimum values of some MS parameters were completely different from those of LC/MS, and that SFC/MS-specific optimization of the analytical conditions is required. Lastly, we evaluated the sensitivity of SFC/MS using fully optimized analytical conditions. As a result, we confirmed that SFC/MS showed much higher sensitivity than LC/MS when the analytical conditions were fully optimized for SFC/MS; and the high sensitivity also increase the number of the compounds that can be detected with good repeatability in real sample analysis. This result indicates that SFC/MS has potential for

Retinoid quantification by HPLC/MS(n)

Science.gov (United States)

McCaffery, Peter; Evans, James; Koul, Omanand; Volpert, Amy; Reid, Kevin; Ullman, M. David

2002-01-01

Retinoic acid (RA) mediates most of the biological effects of vitamin A that are essential for vertebrate survival. It acts through binding to receptors that belong to the nuclear receptor transcription factor superfamily (Mangelsdorf et al. 1994). It is also a highly potent vertebrate teratogen. To determine the function and effects of endogenous and exogenous RA, it is important to have a highly specific, sensitive, accurate, and precise analytical procedure. Current analyses of RA and other retinoids are labor intensive, of poor sensitivity, have limited specificity, or require compatibility with RA reporter cell lines (Chen et al. 1995. BIOCHEM: Pharmacol. 50: 1257-1264; Creech Kraft et al. 1994. BIOCHEM: J. 301: 111-119; Lanvers et al. 1996. J. Chromatogr. B Biomed. Appl. 685: 233-240; Maden et al. 1998. DEVELOPMENT: 125: 4133-4144; Wagner et al. 1992. DEVELOPMENT: 116: 55-66). This paper describes an HPLC/mass spectrometry/mass spectrometry product ion scan (HPLC/MS(n)) procedure for the analysis of retinoids that employs atmospheric pressure chemical ionization MS. The retinoids are separated by normal-phase column chromatography with a linear hexane-isopropanol-dioxane gradient. Each retinoid is detected by a unique series of MS(n) functions set at optimal collision-induced dissociation energy (30% to 32%) for all MS(n) steps. The scan events are divided into three segments, based on HPLC elution order, to maximize the mass spectrometer duty cycle. The all-trans, 9-cis, and 13-cis RA isomers are separated, if desired, by an isocratic hexane-dioxane-isopropanol mobile phase. This paper describes an HPLC/MS(n) procedure possessing high sensitivity and specificity for retinoids.

Transthoracic Doppler echocardiography to predict optimal tube pulsing window for coronary artery CT angiography

Energy Technology Data Exchange (ETDEWEB)

Sun, Gang, E-mail: cjr.sungang@vip.163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Min, E-mail: limin22000@yahoo.com.cn [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Jiang, Xiang-sen, E-mail: jiangxiangsen123@126.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Li, Li, E-mail: leely1976@yahoo.com.cn [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Peng, Zhao-hui, E-mail: zhaohuipeng_R@163.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China); Mu, Nan-nan, E-mail: munannan22000@sohu.com [Department of Medical Imaging, Jinan Military General Hospital, No. 25, Shifan Road, Jinan, Shandong Province 250031 (China)

2012-09-15

Rationale and objective: To evaluate the feasibility of transthoracic Doppler echocardiography to determine the optimal pulsing windows for CT coronary angiography to narrow the pulsing windows further, especially in higher heart rate. Materials and methods: Doppler was performed on 135 patients before CT scanning. For Doppler, the intervals with minimal motion were evaluated during both systole and diastole integrating electrocardiogram (ECG) intervals. For CT scanning, the retrospective ECG-gating was applied and the optimal reconstruction intervals were determined. The accuracy of Doppler analysis to predict the optimal reconstruction intervals was tested. The predicted length of pulsing windows was compared between Doppler analysis and traditional prospective ECG-gating protocol (heart rate ≦ 65 bpm, 60–76%; 66–79 bpm, 30–77%; ≧80 bpm, 31–47%). Results: According to Doppler analysis, the mean length of intervals with minimal motion in systole was 106.4 ± 39.2 ms and 125.2 ± 92.0 ms in diastole. When the intervals with minimal motion during diastole > 90 ms, the optimal reconstruction intervals were located at diastole; otherwise, at systole (P < 0.001). The optimal reconstruction intervals in 93.8% (132/135) patients could be predicted accurately by Doppler analysis. If the optimal reconstruction intervals predicted by Doppler were applied as the exposure windows, the mean length of pulsing windows should has been 105.2 ± 69.4 ms (range: 26.9–510.3 ms), which was significantly shorter than that of traditional prospective ECG-gating protocol (232.0 ± 120.2 ms, range: 93.2–427.3 ms, P < 0.001). Conclusion: Doppler can help detecting the optimal pulsing windows accurately. Prospective ECG-gating incorporating Doppler analysis may narrow pulsing windows significantly while maintaining image quality.

Transthoracic Doppler echocardiography to predict optimal tube pulsing window for coronary artery CT angiography

International Nuclear Information System (INIS)

Sun, Gang; Li, Min; Jiang, Xiang-sen; Li, Li; Peng, Zhao-hui; Mu, Nan-nan

2012-01-01

Rationale and objective: To evaluate the feasibility of transthoracic Doppler echocardiography to determine the optimal pulsing windows for CT coronary angiography to narrow the pulsing windows further, especially in higher heart rate. Materials and methods: Doppler was performed on 135 patients before CT scanning. For Doppler, the intervals with minimal motion were evaluated during both systole and diastole integrating electrocardiogram (ECG) intervals. For CT scanning, the retrospective ECG-gating was applied and the optimal reconstruction intervals were determined. The accuracy of Doppler analysis to predict the optimal reconstruction intervals was tested. The predicted length of pulsing windows was compared between Doppler analysis and traditional prospective ECG-gating protocol (heart rate ≦ 65 bpm, 60–76%; 66–79 bpm, 30–77%; ≧80 bpm, 31–47%). Results: According to Doppler analysis, the mean length of intervals with minimal motion in systole was 106.4 ± 39.2 ms and 125.2 ± 92.0 ms in diastole. When the intervals with minimal motion during diastole > 90 ms, the optimal reconstruction intervals were located at diastole; otherwise, at systole (P < 0.001). The optimal reconstruction intervals in 93.8% (132/135) patients could be predicted accurately by Doppler analysis. If the optimal reconstruction intervals predicted by Doppler were applied as the exposure windows, the mean length of pulsing windows should has been 105.2 ± 69.4 ms (range: 26.9–510.3 ms), which was significantly shorter than that of traditional prospective ECG-gating protocol (232.0 ± 120.2 ms, range: 93.2–427.3 ms, P < 0.001). Conclusion: Doppler can help detecting the optimal pulsing windows accurately. Prospective ECG-gating incorporating Doppler analysis may narrow pulsing windows significantly while maintaining image quality

An automated online turboflow cleanup LC/MS/MS method for the determination of 11 plasticizers in beverages and milk.

Science.gov (United States)

Ates, Ebru; Mittendorf, Klaus; Senyuva, Hamide

2013-01-01

An automated sample preparation technique involving cleanup and analytical separation in a single operation using an online coupled TurboFlow (RP-LC system) is reported. This method eliminates time-consuming sample preparation steps that can be potential sources for cross-contamination in the analysis of plasticizers. Using TurboFlow chromatography, liquid samples were injected directly into the automated system without previous extraction or cleanup. Special cleanup columns enabled specific binding of target compounds; higher MW compounds, i.e., fats and proteins, and other matrix interferences with different chemical properties were removed to waste, prior to LC/MS/MS. Systematic stepwise method development using this new technology in the food safety area is described. Selection of optimum columns and mobile phases for loading onto the cleanup column followed by transfer onto the analytical column and MS detection are critical method parameters. The method was optimized for the assay of 10 phthalates (dimethyl, diethyl, dipropyl, butyl benzyl, diisobutyl, dicyclohexyl, dihexyl, diethylhexyl, diisononyl, and diisododecyl) and one adipate (diethylhexyl) in beverages and milk.

Modeling and optimization by particle swarm embedded neural network for adsorption of zinc (II) by palm kernel shell based activated carbon from aqueous environment.

Science.gov (United States)

Karri, Rama Rao; Sahu, J N

2018-01-15

Zn (II) is one the common pollutant among heavy metals found in industrial effluents. Removal of pollutant from industrial effluents can be accomplished by various techniques, out of which adsorption was found to be an efficient method. Applications of adsorption limits itself due to high cost of adsorbent. In this regard, a low cost adsorbent produced from palm oil kernel shell based agricultural waste is examined for its efficiency to remove Zn (II) from waste water and aqueous solution. The influence of independent process variables like initial concentration, pH, residence time, activated carbon (AC) dosage and process temperature on the removal of Zn (II) by palm kernel shell based AC from batch adsorption process are studied systematically. Based on the design of experimental matrix, 50 experimental runs are performed with each process variable in the experimental range. The optimal values of process variables to achieve maximum removal efficiency is studied using response surface methodology (RSM) and artificial neural network (ANN) approaches. A quadratic model, which consists of first order and second order degree regressive model is developed using the analysis of variance and RSM - CCD framework. The particle swarm optimization which is a meta-heuristic optimization is embedded on the ANN architecture to optimize the search space of neural network. The optimized trained neural network well depicts the testing data and validation data with R 2 equal to 0.9106 and 0.9279 respectively. The outcomes indicates that the superiority of ANN-PSO based model predictions over the quadratic model predictions provided by RSM. Copyright © 2017 Elsevier Ltd. All rights reserved.

[Rapid determination of illicit beta2-agonist additives in health foods and traditional Chinese patent medicines with DCBI-MS/MS method].

Science.gov (United States)

Hou, Yu-Lan; Wu, Shuang; Wang, Hua; Zhao, Yong; Liao, Peng; Tian, Qing-Qing; Sun, Wen-Jian; Chen, Bo

2013-01-01

A novel rapid method for detection of the illicit beta2-agonist additives in health foods and traditional Chinese patent medicines was developed with the desorption corona beam ionization mass spectrometry (DCBI-MS) technique. The DCBI conditions including temperature and sample volume were optimized according to the resulting mass spectra intensity. Matrix effect on 9 beta2-agonists additives was not significant in the proposed rapid determination procedure. All of the 9 target molecules were detected within 1 min. Quantification was achieved based on the typical fragment ion in MS2 spectra of each analyte. The method showed good linear coefficients in the range of 1-100 mg x L(-1) for all analytes. The relative deviation values were between 14.29% and 25.13%. Ten claimed antitussive and antiasthmatic health foods and traditional Chinese patent medicines from local pharmacies were analyzed. All of them were negative with the proposed DCBI-MS method. Without tedious sample pretreatments, the developed DCBI-MS is simple, rapid and sensitive for rapid qualification and semi-quantification of the illicit beta2-agonist additives in health foods and traditional Chinese patent medicines.

Schiff base-chitosan grafted multiwalled carbon nanotubes as a novel solid-phase extraction adsorbent for determination of heavy metal by ICP-MS

Energy Technology Data Exchange (ETDEWEB)

Dai, Bingye; Cao, Meirong; Fang, Guozhen; Liu, Bing; Dong, Xv; Pan, Mingfei [Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin 300457 (China); Wang, Shuo, E-mail: elisasw2002@yahoo.com.cn [Key Laboratory of Food Nutrition and Safety, Ministry of Education, Tianjin Key Laboratory of Food Nutrition and Safety, Tianjin University of Science and Technology, Tianjin 300457 (China)

2012-06-15

Highlights: Black-Right-Pointing-Pointer Schiff base-chitosan grafted MWCNTs were synthesized via covalent modification. Black-Right-Pointing-Pointer The S-CS-MWCNTs were successfully characterized by FT-IR, TEM and TGA. Black-Right-Pointing-Pointer The S-CS-MWCNTs were used for solid-phase extraction of metal ions. Black-Right-Pointing-Pointer A method was developed detection of metal ions from samples coupled with ICP-MS. - Abstract: A novel Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs) solid-phase extraction adsorbent was synthesized by covalently grafting a Schiff base-chitosan (S-CS) onto the surfaces of oxidized MWCNTs. The adsorbent was characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and thermal gravimetric analysis. The results showed that S-CS was successfully grafted onto the surfaces of MWCNTs. A method was developed for the determination of heavy metals, namely V(V), Cr(VI), Cu(II), As(V) and Pb(II) in biological and environmental samples by inductively coupled plasma mass spectrometry coupled with preconcentration with S-CS-MWCNTs. The parameters influencing preconcentration of target ions, such as the pH of the sample solution, the flow rate of sample loading, the eluent concentration, and eluent volume, were investigated and optimized. Under the optimal conditions, the enrichment factors of V(V), Cr(VI), Cu(II), As(V), and Pb(II) reached 111, 95, 60, 52, and 128, respectively, and the detection limits were as low as 1.3-3.8 ng L{sup -1}. The developed method was successfully applied to the determination of trace-metal ions in herring, spinach, river water, and tap water with good recoveries ranging from 91.0% to 105.0%.

Schiff base-chitosan grafted multiwalled carbon nanotubes as a novel solid-phase extraction adsorbent for determination of heavy metal by ICP-MS

International Nuclear Information System (INIS)

Dai, Bingye; Cao, Meirong; Fang, Guozhen; Liu, Bing; Dong, Xv; Pan, Mingfei; Wang, Shuo

2012-01-01

Highlights: ► Schiff base-chitosan grafted MWCNTs were synthesized via covalent modification. ► The S-CS-MWCNTs were successfully characterized by FT-IR, TEM and TGA. ► The S-CS-MWCNTs were used for solid-phase extraction of metal ions. ► A method was developed detection of metal ions from samples coupled with ICP-MS. - Abstract: A novel Schiff base-chitosan-grafted multiwalled carbon nanotubes (S-CS-MWCNTs) solid-phase extraction adsorbent was synthesized by covalently grafting a Schiff base-chitosan (S-CS) onto the surfaces of oxidized MWCNTs. The adsorbent was characterized by Fourier-transform infrared spectroscopy, transmission electron microscopy, and thermal gravimetric analysis. The results showed that S-CS was successfully grafted onto the surfaces of MWCNTs. A method was developed for the determination of heavy metals, namely V(V), Cr(VI), Cu(II), As(V) and Pb(II) in biological and environmental samples by inductively coupled plasma mass spectrometry coupled with preconcentration with S-CS-MWCNTs. The parameters influencing preconcentration of target ions, such as the pH of the sample solution, the flow rate of sample loading, the eluent concentration, and eluent volume, were investigated and optimized. Under the optimal conditions, the enrichment factors of V(V), Cr(VI), Cu(II), As(V), and Pb(II) reached 111, 95, 60, 52, and 128, respectively, and the detection limits were as low as 1.3–3.8 ng L −1 . The developed method was successfully applied to the determination of trace-metal ions in herring, spinach, river water, and tap water with good recoveries ranging from 91.0% to 105.0%.

Determinação simultânea de resíduos de cloranfenicol, tianfenicol e florfenicol em leite bovino por cromatografia eletrocinética micelar

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Leonardo Pezza

2006-10-01

Full Text Available A micellar electrokinetic chromatographic method (MEKC is described for determining residues of amphenicols(chloramphenicol,thiamphenicol and florfenicol in bovine milk. MEKC is conducted by using a separation buffer consisting of 20 mM Na2HPO4, 10 mM Na2B4O7, 50 mM SDS at pH 8.0; UV detection at 210 nm and 10 kV of voltage. The limit of detection ranged from 4.3-5.3 µg L-1. The MEKC method was applied for the simultaneous determination of amphenicols in milk samples spiked with amphenicols at three concentration levels: 10, 30 and 50 µg L-1. Recoveries ranging from 91-105% were obtained by following a simple extraction/preconcentration procedure.

Determinação simultânea de resíduos de cloranfenicol, tianfenicol e florfenicol em leite bovino por cromatografia eletrocinética micelar

Directory of Open Access Journals (Sweden)

Pezza Leonardo

2006-01-01

Full Text Available A micellar electrokinetic chromatographic method (MEKC is described for determining residues of amphenicols(chloramphenicol,thiamphenicol and florfenicol in bovine milk. MEKC is conducted by using a separation buffer consisting of 20 mM Na2HPO4, 10 mM Na2B4O7, 50 mM SDS at pH 8.0; UV detection at 210 nm and 10 kV of voltage. The limit of detection ranged from 4.3-5.3 µg L-1. The MEKC method was applied for the simultaneous determination of amphenicols in milk samples spiked with amphenicols at three concentration levels: 10, 30 and 50 µg L-1. Recoveries ranging from 91-105% were obtained by following a simple extraction/preconcentration procedure.

Identification of phase-II metabolites of flavonoids by liquid chromatography-ion-mobility spectrometry-mass spectrometry.

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Chalet, Clément; Hollebrands, Boudewijn; Janssen, Hans-Gerd; Augustijns, Patrick; Duchateau, Guus

2018-01-01

Flavonoids are a class of natural compounds with a broad range of potentially beneficial health properties. They are subjected to an extensive intestinal phase-II metabolism, i.e., conjugation to glucuronic acid, sulfate, and methyl groups. Flavonoids and their metabolites can interact with drug transporters and thus interfere with drug absorption, causing food-drug interactions. The site of metabolism plays a key role in the activity, but the identification of the various metabolites remains a challenge. Here, we developed an analytical method to identify the phase-II metabolites of structurally similar flavonoids. We used liquid chromatography-ion-mobility spectrometry-mass spectrometry (LC-IMS-MS) analysis to identify phase-II metabolites of flavonols, flavones, and catechins produced by HT29 cells. We showed that IMS could bring valuable structural information on the different positional isomers of the flavonols and flavones. The position of the glucuronide moiety had a strong influence on the collision cross section (CCS) of the metabolites, with only minor contribution of hydroxyl and methyl moieties. For the catechins, fragmentation data obtained from MS/MS analysis appeared more useful than IMS to determine the structure of the metabolites, mostly due to the high number of metabolites formed. Nevertheless, CCS information as a molecular fingerprint proved to be useful to identify peaks from complex mixtures. LC-IMS-MS thus appears as a valuable tool for the identification of phase-II metabolites of flavonoids. Graphical abstract Structural identification of phase-II metabolites of flavonoids using LC-IMS-MS.

LC-MS (/MS) in clinical toxicology screening methods.

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Viette, Véronique; Hochstrasser, Denis; Fathi, Marc

2012-01-01

Toxicological screening is the analysis of biological samples to detect and identify unknown compounds. The high selectivity and sensitivity of liquid chromatography (LC) coupled to mass spectrometry (MS) or tandem mass spectrometry (MS/MS) technology provide an attractive alternative to the current methods (LC-UV, GC/MS, etc.). For these reasons, an increasing number of applications are being published. This paper is a brief overview of LC-MS(/MS) screening methods developed for clinical toxicology in recent years. Various sample treatments, chromatographic separations and detection by mass spectrometry can be combined to obtain screening methods adapted to the constraints and needs of clinical toxicology laboratories. Currently the techniques are in the hands of specialists, mainly in academic institutions. However, the evolution in technology should allow application of these techniques as a tool in toxicology laboratories, thus allowing a more widespread exploitation of their potential.

Development of a SIDA-LC-MS/MS Method for the Determination of Phomopsin A in Legumes.

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Schloß, Svenja; Koch, Matthias; Rohn, Sascha; Maul, Ronald

2015-12-09

A novel method for the determination of phomopsin A (1) in lupin flour, pea flour, and bean flour as well as whole lupin plants was established based on stable isotope dilution assay (SIDA) LC-MS/MS using (15)N6-1 as an isotopically labeled internal standard. Artificially infected samples were used to develop an optimized extraction procedure and sample pretreatment. The limits of detection were 0.5-1 μg/kg for all matrices. The limits of quantitation were 2-4 μg/kg. The method was used to analyze flour samples generated from selected legume seeds and lupin plant samples that had been inoculated with Diaporthe toxica and two further fungal strains. Finally, growing lupin plants infected with D. toxica were investigated to simulate a naturally in-field mycotoxicosis. Toxin levels of up to 10.1 μg/kg of 1 were found in the pods and 7.2 μg/kg in the stems and leaves.

Optimization of induction, subculture conditions, and growth kinetics of Angelica sinensis (Oliv.) Diels callus.

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Huang, Bing; Han, Lijuan; Li, Shaomei; Yan, Chunyan

2015-01-01

Angelica sinensis (Oliv.) Diels is an important traditional Chinese medicine, and the medicinal position is its root. This perennial herb grows vigorously only in specific areas and the environment. Tissue culture induction of callus and plant regeneration is an important and effective way to obtain large scale cultures of A. sinensis. The objective was to optimize the inductive, subculture conditions, and growth kinetics of A. sinensis. Tissue culture conditions for A. sinensis were optimized using leaves and petioles (types I and II) as explants source. Murashige and Skoog (MS) and H media supplemented with 30 g/L sucrose, 7.5 g/L agar, and varying concentrations of plant growth regulators were used for callus induction. In addition, four different basal media supplemented with 1.0 mg/L 2,4-dichlorophenoxy acetic acid (2,4-D), 0.2 mg/L 6-benzyladenine (BA) and 30 g/L sucrose were optimized for callus subculture. Finally, growth kinetics of A. sinensis cultured on different subculture media was investigated based on callus properties, including fresh weight, dry weight, medium pH, callus relative fresh weight growth, callus relative growth rate (CRGR), and sucrose content. MS medium supplemented with 5 mg/L α-naphthaleneacetic acid, 0.5 mg/L BA, 0.7 mg/L 2,4-D, 30 g/L sucrose and 7.5 g/L agar resulted in optimal callus induction in A. sinensis while petiole I was found as the best plant organ for callus induction. The B5 medium supplemented with 1.0 mg/L 2,4-D, 0.2 mg/L BA and 30 g/L sucrose displayed the best results in A. sinensis callus subculture assays. The optimized conditions could be one of the most potent methods for large-scale tissue culture of A. sinensis.

LC-MS/MS assay for the quantitation of the tyrosine kinase inhibitor neratinib in human plasma.

Science.gov (United States)

Kiesel, Brian F; Parise, Robert A; Wong, Alvin; Keyvanjah, Kiana; Jacobs, Samuel; Beumer, Jan H

2017-02-05

Neratinib is an orally available tyrosine kinase inhibitor targeting HER2 (ERBB2) and EGFR (ERBB). It is being clinically evaluated for the treatment of breast and other solid tumors types as a single agent or in combination with other chemotherapies. In support of several phase I/II clinical trials investigating neratinib combinations, we developed and validated a novel LC-MS/MS assay for the quantification of neratinib in 100μL of human plasma with a stable isotopic internal standard. Analytes were extracted from plasma using protein precipitation and evaporation of the resulting supernatant followed by resuspension. Chromatographic separation was achieved using an Acquity UPLC BEH Shield RP18 column and a gradient methanol-water mobile phase containing 10% ammonium acetate. An ABI 4000 mass spectrometer and electrospray positive mode ionization were used for detection. The assay was linear from 2 to 1,000ng/mL and proved to be accurate (98.9-106.5%) and precise (neratinib. Copyright © 2016 Elsevier B.V. All rights reserved.

Characterization and Clearance of m/s Sigyn

International Nuclear Information System (INIS)

Jiselmark, Jonatan; Vreede, Patrick

2016-01-01

M/s Sigyn was a 2044 ton ship that transported contaminated material between 1982 and 2013. Most of the transports were with spent nuclear fuel between Swedish nuclear power plants and the Swedish fuel repository, Clab. In addition to spent fuel, m/s Sigyn also transported big contaminated components, from nuclear power plants in Europe, to Studsvik for analysis or decontamination and melting. She also transported components from Swedish nuclear power plants to final disposal of short lived waste, SFR. Even though all transported items have been cleaned, checked and wrapped with plastics, some activity ended up as contamination onboard. In December 2013 it was decided that m/s Sigyn was subject for decommissioning due to her age. This Paper describes the method in which the activity onboard m/s Sigyn was characterized and clearance levels were calculated. This method for radiological characterization and clearance has recently been developed in Sweden, the method is efficient in that it does not need a big pre characterization survey. Only the nuclide distribution and history of the object, is needed to start the final survey. In the future there will be further development of the method, making it possible to reduce the number of measurements even more. This will further optimize the method and reduce the cost for final surveys and clearance. (authors)

Effect of low concentration sodium dodecyl sulfate on the electromigration of palonosetron hydrochloride stereoisomers in micellar electrokinetic chromatography.

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Hu, Shao-Qiang; Wang, Gui-Xia; Guo, Wen-Bo; Guo, Xu-Ming; Zhao, Min

2014-05-16

The effect of low concentrations of sodium dodecyl sulfate (SDS) on the separation of palonosetron hydrochloride (PALO) stereoisomers by micellar electrokinetic chromatography (MEKC) has been investigated. It was found that the addition of SDS prolongs the migration time and the migration order of four stereoisomers changes regularly with the SDS concentration. Good separations for all the four stereoisomers were achieved at appropriate SDS concentration. The effect of SDS on the electromigration (mobilities) of PALO stereoisomers has been studied, in order to explain its effect on the separation by MEKC. It was found that low concentrations of SDS added into the separation media forms negatively charged complexes with PALO stereoisomers and hence reverses their electromigration direction. Furthermore, the migration order between two enantiomeric pairs is also reversed because the enantiomeric pair with a bigger positive mobility than that of another pair turns to have a bigger negative mobility when bound with SDS. Based on these results, the effect of SDS on the MEKC separation of PALO stereoisomers was elucidated reasonably. The performance of the developed chiral MEKC method was validated by the analysis of a real sample. Copyright © 2014 Elsevier B.V. All rights reserved.

Two-dimensional HPLC coupled to ICP-MS and electrospray ionisation (ESI)-MS/MS for investigating the bioavailability in vitro of arsenic species from edible seaweed

Energy Technology Data Exchange (ETDEWEB)

Garcia-Sartal, Cristina; Barciela-Alonso, Maria del Carmen; Bermejo-Barrera, Pilar [University of Santiago de Compostela, Department of Analytical Chemistry, Nutrition and Bromatology, Faculty of Chemistry, Santiago de Compostela (Spain); Taebunpakul, Sutthinun [LGC Limited, Teddington, Middlesex (United Kingdom); Imperial College of Science, Technology and Medicine, South Kensington, Department of Materials, London (United Kingdom); National Institute of Metrology (Thailand), Pathumthani (Thailand); Stokes, Emma; Goenaga-Infante, Heidi [LGC Limited, Teddington, Middlesex (United Kingdom)

2012-04-15

Edible seaweed consumption is a route of exposure to arsenic. However, little attention has been paid to estimate the bioaccessibility and/or bioavailability of arsenosugars in edible seaweed and their possible degradation products during gastrointestinal digestion. This work presents first use of combined inductively coupled plasma mass spectroscopy (ICP-MS) with electrospray ionization tandem mass spectrometry (ESI-MS/MS) with two-dimensional HPLC (size exclusion followed by anion exchange) to compare the qualitative and quantitative arsenosugars speciation of different edible seaweed with that of their bioavailable fraction as obtained using an in vitro gastrointestinal digestion procedure. Optimal extraction conditions for As species from four seaweed namely kombu, wakame, nori and sea lettuce were selected as a compromise between As extraction efficiency and preservation of compound identity. For most investigated samples, the use of ammonium acetate buffer as extractant and 1 h sonication in a water bath followed by HPLC-ICP-MS resulted in 40-61% of the total As to be found in the buffered aqueous extract, of which 86-110% was present as arsenosugars (glycerol sugar, phosphate sugar and sulfonate sugar for wakame and kombu and glycerol sugar and phosphate sugar for nori). The exception was sea lettuce, for which the arsenosugar fraction (glycerol sugar, phosphate sugar) only comprised 44% of the total extracted As. Interestingly, the ratio of arsenobetaine and dimethylarsinic acid to arsenosugars in sea lettuce extracts seemed higher than that for the rest of investigated samples. After in vitro gastrointestinal digestion, approximately 11-16% of the total As in the solid sample was found in the dialyzates with arsenosugars comprising 93-120% and 41% of the dialyzable As fraction for kombu, wakame, nori and sea lettuce, respectively. Moreover, the relative As species distribution in seaweed-buffered extracts and dialyzates was found to be very similar

Substrate optimization and clinical validation of reporter peptides for MS-based protease profiling in serum specimens: a new approach for diagnosis of malignant disease.

Science.gov (United States)

Yepes, Diego; Jacob, Anette; Dauber, Marc; Costina, Victor; Hofheinz, Ralf; Neumaier, Michael; Findeisen, Peter

2011-07-01

The progression of many solid tumors is characterized by the release of tumor-associated proteases, such as cancer procoagulant, MMP2 and MMP7. Consequently, the detection of tumor-specific proteolytic activity in serum specimens has recently been proposed as a new diagnostic tool in oncology. However, tumor-associated proteases are highly diluted in serum specimens and it is challenging to identify substrates that are specifically cleaved. In this study, we describe the systematic optimization of a synthetic peptide substrate using a positional scanning synthetic combinatorial library (PS-SCL) approach. The initial reporter peptide (RP) comprises of the cleavage site, WKPYDAAD, that is part of the coagulation factor X, the natural substrate of the tumor-associated cysteine protease cancer procoagulant (EC 3.4.22.26). Specifically, the amino acid substitution of aspartatic acid (D) in position P1' against asparagine (N) improved the processing of respective RPs in serum specimens from patients with colorectal tumors compared to healthy controls. Proteolytic fragments of RPs accumulated during prolonged incubation with serum specimens and were quantified with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Finally, the optimized RP with the cleaved motif WKPYNAAD was combined with the RPs, VPLSLTMG and IPVSLRSG, that were cleaved by the tumor-associated proteases, MMP2 and MMP7, respectively. The diagnostic accuracy of MS-based protease profiling was evaluated for this triplex RP mix in a cohort of 50 serum specimens equally divided into colorectal cancer patients and healthy control individuals. Multiparametric analysis showed an AUC value of 0.90 for the receiver operating characteristic curve and was superior to the classification accuracy of the single markers. Our results demonstrate that RPs for MS-based protease profiling can systematically be optimized with a PS-SCL. Furthermore, the combination of different RPs can

Analysis of acrylamide by LC-MS/MS and GC-MS in processed Japanese foods.

Science.gov (United States)

Ono, H; Chuda, Y; Ohnishi-Kameyama, M; Yada, H; Ishizaka, M; Kobayashi, H; Yoshida, M

2003-03-01

Acrylamide concentrations in processed foods (63 samples covering 31 product types) from Japan were analysed by LC-MS/MS and GC-MS methods. The limit of detection and limit of quantification of acrylamide were 0.2 ng x ml(-1) (6 fmol) and 0.8 ng x ml(-1) (22 fmol), respectively, by LC-MS/MS, and those of 2,3-dibromopropionamide derived from acrylamide were 12 ng x ml(-1) (52 fmol) and 40 ng x ml(-1) (170 fmol), respectively, by GC-MS. Repeatability given as RSD was 1000 microg x kg(-1). The concentrations in non-whole potato-based snacks, rice crackers processed by grilling or frying, and candied sweet potatoes were lower compared with those in the potato crisps and the whole potato-based fried snacks. One of the whole potato-based fried snacks, however, showed low acrylamide concentration (instant precooked noodles and won-tons were <100 microg x kg(-1) with only one exception. Roasted barley grains for 'Mugi-cha' tea contained 200-600 microg x kg(-1) acrylamide.

Validation of Multibody Program to Optimize Simulated Trajectories II Parachute Simulation with Interacting Forces

Science.gov (United States)

Raiszadeh, Behzad; Queen, Eric M.; Hotchko, Nathaniel J.

2009-01-01

A capability to simulate trajectories of multiple interacting rigid bodies has been developed, tested and validated. This capability uses the Program to Optimize Simulated Trajectories II (POST 2). The standard version of POST 2 allows trajectory simulation of multiple bodies without force interaction. In the current implementation, the force interaction between the parachute and the suspended bodies has been modeled using flexible lines, allowing accurate trajectory simulation of the individual bodies in flight. The POST 2 multibody capability is intended to be general purpose and applicable to any parachute entry trajectory simulation. This research paper explains the motivation for multibody parachute simulation, discusses implementation methods, and presents validation of this capability.

Misleading measures in Vitamin D analysis: A novel LC-MS/MS assay to account for epimers and isobars

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Petroczi Andrea

2011-05-01

Full Text Available Abstract Background Recently, the accuracies of many commercially available immunoassays for Vitamin D have been questioned. Liquid chromatography tandem mass spectrometry (LC- MS/MS has been shown to facilitate accurate separation and quantification of the major circulating metabolite 25-hydroxyvitamin-D3 (25OHD3 and 25-hydroxyvitamin-D2 (25OHD2 collectively termed as 25OHD. However, among other interferents, this method may be compromised by overlapping peaks and identical masses of epimers and isobars, resulting in inaccuracies in circulating 25OHD measurements. The aim of this study was to develop a novel LC-MS/MS method that can accurately identify and quantitate 25OHD3 and 25OHD2 through chromatographic separation of 25OHD from its epimers and isobars. Methods A positive ion electrospray ionisation (ESI LC-MS/MS method was used in the Multiple Reaction Monitoring (MRM mode for quantification. It involved i liquid-liquid extraction, ii tandem columns (a high resolution ZORBAX C18 coupled to an ULTRON chiral, with guard column and inlet filter, iii Stanozolol-D3 as internal standard, and iv identification via ESI and monitoring of three fragmentation transitions. To demonstrate the practical usefulness of our method, blood samples were collected from 5 healthy male Caucasian volunteers; age range 22 to 37 years and 25OHD2, 25OHD3 along with co-eluting epimers and analogues were quantified. Results The new method allowed chromatographic separation and quantification of 25OHD2, 25OHD3, along with 25OHD3 epimer 3-epi-25OHD3 and isobars 1-α-hydroxyvitamin-D3 (1αOHD3, and 7-α-hydroxy-4-cholesten-3-one (7αC4. The new assay was capable of detecting 0.25 ng/mL of all analytes in serum. Conclusions To our knowledge, this is the first specific, reliable, reproducible and robust LC-MS/MS method developed for the accurate detection of 25OHD (Vitamin D. The method is capable of detecting low levels of 25OHD3 and 25OHD2 together with chromatographic

Urinary amino acid analysis: a comparison of iTRAQ-LC-MS/MS, GC-MS, and amino acid analyzer.

Science.gov (United States)

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J

2009-07-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines.

Optimization of reagent concentration for radioiodination of rat C-peptide II in development of radioimmunoassay procedure for rats

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B R Manupriya

2018-01-01

Full Text Available Rat C-peptide is a polypeptide molecule made up of 31 amino acids and secreted from pancreas into circulation in two isoforms I and II. Quantification of rat C-peptide II in rat serum is important as it is directly related to the diagnosis of carbohydrate metabolism abnormalities, pancreatic performance analysis, monitoring of hypoglycemia, and diabetes-related illness in rat model. The aim of the present work is to develop a tracer by chloramine-T method for radioimmunoassay (RIA procedure and to determine the optimum amount of chloramine-T required for the preparation of stable radioiodinated product with a specific activity of around 24.97 MBq/μg, corresponding to 1 125I atom per molecule of the peptide. Tyrosylated rat C-peptide II was selected for the radioiodination procedure as rat C-peptide II does not contain either tyrosine or histidine which is mandatory for the incorporation of 125I atom to the rat C-peptide II. Tyrosylated rat C-peptide II was subjected to radioiodination by chloramine-T method with different concentrations of chloramine-T and sodium metabisulfite (MBS to obtain a stable radiolabeled compound. Optimized reaction conditions relating to the concentration of chloramine-T (10 μg and MBS (20 μg yielded a stable 125I-rat C-peptide II with specific activity of 21.01 MBq/μg corresponding to 0.84 125I atoms per molecule of the peptide. Preparation of high integrity tracer of rat C-peptide II was achieved by combining one molecule of oxidant (chloramine-T and two molecule of reductant (MBS.

Quantifying fenbendazole and its metabolites in self-medicating wild red grouse Lagopus lagopus scoticus using an HPLC-MS-MS approach.

Science.gov (United States)

Adam, Aileen; Webster, Lucy M I; Mullen, William; Keller, Lukas F; Johnson, Paul C D

2011-05-11

On red grouse estates in the UK the nematode parasite Trichostrongylus tenuis is often controlled by application of grit medicated with the anthelmintic fenbendazole (FBZ). To date, assessment of the efficacy has been inhibited by the inability to quantify uptake of FBZ by the birds. We have developed a simple and sensitive HPLC-MS-MS method for detecting and quantifying FBZ and its metabolites from a 300 mg sample of red grouse liver. This method could be used to improve the efficacy of medicated grit treatment by allowing the identification of conditions and application methods that optimize the uptake of FBZ. With the necessary modifications, our method will also be applicable to other wildlife species where self-medication is used for parasite control. Copyright © 2011 Elsevier B.V. All rights reserved.

Optimized Gen-II FeCrAl cladding production in large quantity for campaign testing

Energy Technology Data Exchange (ETDEWEB)

Yamamoto, Yukinori [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Sun, Zhiqian [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Terrani, Kurt A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2016-06-03

There are two major objectives in this report; (1) to optimize microstructure control of ATF FeCrAl alloys during tube drawing processes, and (2) to provide an update on the progress of ATF FeCrAl tube production via commercial manufacturers. Experimental efforts have been made to optimize the process parameters balancing the tube fabricability, especially for tube drawing processes, and microstructure control of the final tube products. Lab-scale sheet materials of Gen II FeCrAl alloys (Mo-containing and Nb-containing FeCrAl alloys) were used in the study, combined with a stepwise warm-rolling process and intermediate annealing, aiming to simulate the tube drawing process in a commercial tube manufacturer. The intermediate annealing at 650ºC for 1h was suggested for the tube-drawing process of Mo-containing FeCrAl alloys because it successfully softened the material by recovering the work hardening introduced through the rolling step, without inducing grain coarsening due to recrystallization. The final tube product is expected to have stabilized deformed microstructure providing the improved tensile properties with sufficient ductility. Optimization efforts on Nb-containing FeCrAl alloys focused on the effect of alloying additions and annealing conditions on the stability of deformed microstructure. Relationships between the second-phase precipitates (Fe₂Nb-Laves phase) and microstructure stability are discussed. FeCrAl tube production through commercial tube manufacturers is currently in progress. Three different manufacturers, Century Tubes, Inc. (CTI), Rhenium Alloys, Inc. (RAI), and Superior Tube Company, Inc. (STC), are providing capabilities for cold-drawing, warm-drawing, and HPTR cold-pilgering, respectively. The first two companies are currently working on large quantity tube production (expected 250 ft length) of Gen I model FeCrAl alloy (B136Y3, at CTI) and Gen II (C35M4, at RAI), with the process parameters obtained from the experimental

Optimizing treatment success in multiple sclerosis

OpenAIRE

Ziemssen, T; Derfuss, T; de Stefano, N; Giovannoni, G; Palavra, F; Tomic, D; Vollmer, T; Schippling, S

2016-01-01

Despite important advances in the treatment of multiple sclerosis (MS) over recent years, the introduction of several disease-modifying therapies (DMTs), the burden of progressive disability and premature mortality associated with the condition remains substantial. This burden, together with the high healthcare and societal costs associated with MS, creates a compelling case for early treatment optimization with highly efficacious therapies. Often, patients receive several first-line therapie...

Homocysteine is the confounding factor of metabolic syndrome-confirmed by siMS score.

Science.gov (United States)

Srećković, Branko; Soldatovic, Ivan; Colak, Emina; Mrdovic, Igor; Sumarac-Dumanovic, Mirjana; Janeski, Hristina; Janeski, Nenad; Gacic, Jasna; Dimitrijevic-Sreckovic, Vesna

2018-04-06

Abdominal adiposity has a central role in developing insulin resistance (IR) by releasing pro-inflammatory cytokines. Patients with metabolic syndrome (MS) have higher values of homocysteine. Hyperhomocysteinemia correlates with IR, increasing the oxidative stress. Oxidative stress causes endothelial dysfunction, hypertension and atherosclerosis. The objective of the study was to examine the correlation of homocysteine with siMS score and siMS risk score and with other MS co-founding factors. The study included 69 obese individuals (age over 30, body mass index [BMI] >25 kg/m2), classified into two groups: I-with MS (33 patients); II-without MS (36 patients). Measurements included: anthropometric parameters, lipids, glucose regulation parameters and inflammation parameters. IR was determined by homeostatic model assessment for insulin resistance (HOMA-IR). ATP III classification was applied for diagnosing MS. SiMS score was used as continuous measure of metabolic syndrome. A significant difference between groups was found for C-reactive protein (CRP) (psiMS risk score showed a positive correlation with homocysteine (p=0.023), while siMS score correlated positively with fibrinogen (p=0.013), CRP and acidum uricum (p=0.000) and homocysteine (p=0.08). Homocysteine correlated positively with ApoB (p=0.036), HbA1c (p=0.047), HOMA-IR (p=0.008) and negatively with ApoE (p=0.042). Correlation of siMS score with homocysteine, fibrinogen, CRP and acidum uricum indicates that they are co-founding factors of MS. siMS risk score correlation with homocysteine indicates that hyperhomocysteinemia increases with age. Hyperhomocysteinemia is linked with genetic factors and family nutritional scheme, increasing the risk for atherosclerosis.

Urinary Amino Acid Analysis: A Comparison of iTRAQ®-LC-MS/MS, GC-MS, and Amino Acid Analyzer

Science.gov (United States)

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L.; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J.

2009-01-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ® derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ® tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ®-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27±5.22, 21.18±10.94, and 18.34±14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39±5.35, 6.23±3.84, and 35.37±29.42. Both GC-MS and iTRAQ®-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. PMID:19481989

Development of Multi-Service (MS) for SAC-OCDMA systems

Science.gov (United States)

Kakaee, Majid H.; Seyedzadeh, Saleh; Adnan Fadhil, Hilal; Barirah Ahmad Anas, Siti; Mokhtar, Makhfudzah

2014-08-01

A Multi-Service Optical Code Division Multiple Access (MS-OCDMA) code based on Spectral Amplitude Coding (SAC) is proposed in this paper. The advantage of proposed code on setting a variable number of users in a basic code matrix with a fixed code weight makes it more flexible in generating codewords. The appropriate quality of service required for various network applications can be provided by choosing a different number of users for the basic code matrix of MS code. The properties of the proposed code is compared with other OCDMA codes in terms of code length and maximum cross-correlation. The performance of the MS code mathematically analysed and probability of error for users is plotted as a function of the number of active users and optical received power. Shot, phase induced intensity and thermal noises are considered in mathematical analysis. Results show that by choosing code weight of 4 and optimizing number of users per sequence, the MS code supports up to 82 users, each operating at a bit-rate of 622 Mbps with reference to the Bit Error Rate (BER) of 10-9.

Optimal synthesis of a Ni(II)-dimethylglyoxime ion-imprinted polymer ...

African Journals Online (AJOL)

A Ni(II)-dimethylglyoxime ion-imprinted polymer {Ni(II)-DMG IIP} was optimised by the uniform design experimental method and used to adsorb Ni(II) ions from water, soil and mine tailing samples. This aimed to improve the performance of this ion-imprinted polymer in trapping Ni(II) ions from soil and mine tailing samples ...

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

Science.gov (United States)

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

2015-05-01

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

Multiple Sclerosis-related Uveitis: Does MS Treatment Affect Uveitis Course?

Science.gov (United States)

Jouve, Léa; Benrabah, Rabah; Héron, Emmanuel; Bodaghi, Bahram; Le Hoang, Phuc; Touitou, Valérie

2017-06-01

Few data are available regarding the optimal treatment of multiple sclerosis (MS)-related uveitis. The aim of this study was to describe clinical features of MS-associated uveitis and determine how MS treatment affects the course of uveitis. Retrospective, multicenter study. Patients were divided into two groups according to the use (group 2) or not (group 1) of immunomodulatory drugs. Characteristics of uveitis and treatment were reviewed. A total of 68 eyes from 36 patients (17 in group 1 and 19 in group 2) were included. All patients were treated with topical and/or systemic steroids for uveitis. Uveitis occurred 1-17 years prior to neurologic symptoms in 78% of patients. Uveitis was more severe in group 2 (puveitis (p = 0.06). MS-related uveitis has often a favorable evolution. Patients on interferon-beta have more severe and chronic uveitis. As far as we are concerned, interferon-beta given on the sole indication of uveitis is not recommended. If steroid-sparing agent is required for intraocular inflammation, immunosuppressive drugs should be considered.

Simultaneous quantitation of hydroxychloroquine and its metabolites in mouse blood and tissues using LC-ESI-MS/MS: An application for pharmacokinetic studies.

Science.gov (United States)

Chhonker, Yashpal S; Sleightholm, Richard L; Li, Jing; Oupický, David; Murry, Daryl J

2018-01-01

Hydroxychloroquine (HCQ) has been shown to disrupt autophagy and sensitize cancer cells to radiation and chemotherapeutic agents. However, the optimal delivery method, dose, and tumor concentrations required for these effects are not known. This is in part due to a lack of sensitive and reproducible analytical methods for HCQ quantitation in small animals. As such, we developed and validated a selective and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for simultaneous quantitation of hydroxychloroquine and its metabolites in mouse blood and tissues. The chromatographic separation and detection of analytes were achieved on a reversed phase Thermo Aquasil C 18 (50×4.6mm, 3μ) column, with gradient elution using 0.2% formic acid and 0.1% formic acid in methanol as mobile phase at a flow rate of 0.5mL/min. Simple protein precipitation was utilized for extraction of analytes from the desired matrix. Analytes were separated and quantitated using MS/MS with an electrospray ionization source in positive multiple reaction monitoring (MRM) mode. The MS/MS response was linear over the concentration range from 1 to 2000ng/mL for all analytes with a correlation coefficient (R 2 ) of 0.998 or better. The within- and between-day precision (relative standard deviation, % RSD) and accuracy were within the acceptable limits per FDA guidelines. The validated method was successfully applied to a preclinical pharmacokinetic mouse study involving low volume blood and tissue samples for hydroxychloroquine and metabolites. Copyright © 2017 Elsevier B.V. All rights reserved.

Selenium speciation analysis of Misgurnus anguillicaudatus selenoprotein by HPLC-ICP-MS and HPLC-ESI-MS/MS

Science.gov (United States)

Analytical methods for selenium (Se) speciation were developed using high performance liquid chromatography (HPLC) coupled to either inductively coupled plasma mass spectrometry (ICP-MS) or electrospray ionization tandem mass spectrometry (ESI-MS/MS). Separations of selenomethionine (Se-Met) and sel...

Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection

Energy Technology Data Exchange (ETDEWEB)

Zhang Nan [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China); Hu Bin, E-mail: binhu@whu.edu.cn [Key Laboratory of Analytical Chemistry for Biology and Medicine (Ministry of Education), Department of Chemistry, Wuhan University, Wuhan 430072 (China)

2012-04-20

Graphical abstract: Ion imprinted 3-mercaptopropyltrimethoxysilane (MPTS) coated stir bar for selective extraction of trace Cd(II). Highlights: Black-Right-Pointing-Pointer Ion imprinted polymers were proposed as the coating for SBSE for the first time. Black-Right-Pointing-Pointer Cd(II) imprinted MPTS-silica coating was prepared by a double-imprinting concept. Black-Right-Pointing-Pointer A novel method of SBSE-ICP-MS was developed for the determination of Cd in waters. Black-Right-Pointing-Pointer This method is rapid, selective, sensitive and applicable for determining trace Cd(II) in waters. - Abstract: Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol-gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 {mu}g and 0.8 {mu}g bar{sup -1}. The detection limit (3{sigma}) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L{sup -1} and the relative standard

Cadmium (II) imprinted 3-mercaptopropyltrimethoxysilane coated stir bar for selective extraction of trace cadmium from environmental water samples followed by inductively coupled plasma mass spectrometry detection

International Nuclear Information System (INIS)

Zhang Nan; Hu Bin

2012-01-01

Graphical abstract: Ion imprinted 3-mercaptopropyltrimethoxysilane (MPTS) coated stir bar for selective extraction of trace Cd(II). Highlights: ► Ion imprinted polymers were proposed as the coating for SBSE for the first time. ► Cd(II) imprinted MPTS-silica coating was prepared by a double-imprinting concept. ► A novel method of SBSE–ICP-MS was developed for the determination of Cd in waters. ► This method is rapid, selective, sensitive and applicable for determining trace Cd(II) in waters. - Abstract: Cd(II) imprinted 3-mercaptopropyltrimethoxysilane (MPTS)-silica coated stir bar was prepared by sol–gel technique combining with a double-imprinting concept for the first time and was employed for stir bar sorptive extraction (SBSE) of trace Cd(II) from water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. A tetramethoxysilane (TMOS) coating was first in situ created on the glass bar surface. Afterward, a sol solution containing MPTS as the functional precursor, ethanol as the solvent and both Cd(II) and surfactant micelles (cetyltrimethylammonium bromide, CTAB) as the template was again coated on the TMOS bar. The structures of the stir bar coating were characterized by FT-IR spectroscopy. Round-bottom vial was used for the extraction of Cd(II) by SBSE to avoid abrasion of stir bar coatings. The factors affecting the extraction of Cd(II) by SBSE such as pH, stirring rate and time, sample/elution volume and interfering ions have been investigated in detail, and the optimized experimental parameters were obtained. Under the optimized conditions, the adsorption capacities of non-imprinted and imprinted coating stir bars were found to be 0.5 μg and 0.8 μg bar −1 . The detection limit (3σ) based on three times standard deviations of the method blanks by 7 replicates was 4.40 ng L −1 and the relative standard deviation (RSD) was 3.38% (c = 1 μg L −1 , n = 7). The proposed method was successfully applied for the

Combined evaluation of personality, risk and coping in MS patients: A step towards individualized treatment choice - The PeRiCoMS-Study I.

Science.gov (United States)

Bsteh, G; Monz, E; Zamarian, L; Hagspiel, S; Hegen, H; Auer, M; Wurth, S; Di Pauli, F; Deisenhammer, F; Berger, T

2017-05-15

Multiple sclerosis (MS) is a chronic inflammatory neurological disease requiring disease-modifying treatment (DMT). To provide patients with the optimal individual therapeutic option, treatment recommendations should be based not only on individual disease course and DMT specific benefit-risk estimates, but also on patient's individual characteristics such as personality, risk attitude and coping strategies. However, these characteristics are difficult to objectify in clinical routine practice without the support of appropriate evaluation instruments. To identify and to assemble an objective test battery measuring personality, risk attitude and coping strategies in MS patients. A comprehensive literature search was performed to obtain all questionnaires assessing personality, risk attitude and coping strategies. Availability in German language, validation in a published normative collective and a reliability of >0.70 were required for our purposes. Based on these criteria, we chose the Big-Five-Personality Test, UPPS Impulsive Behaviour Scale, Domain-Specific Risk-Taking scale (DOSPERT), Brief-COPE and Stress & Coping Inventory (SCI). Results were compared to published normative controls of the respective questionnaires. Out of 22 MS patients (7 males, 15 females) participating in this study, 19 (86.4%) completed all questionnaires. The median completion time was 45min (min-max range: 25-60min). The median scores of the MS group were within the average range of published control samples in all questionnaires. We report that traits of personality, risk attitude and coping strategies can be effectively and feasibly tested in MS patients by the instruments used in our exploratory study. There were no differences between MS patients and healthy controls, thus enabling assessment without being influenced by the diagnosis of MS. After validation in a larger cohort the "PeRiCoMS"-battery will be useful as another step towards a more individualized shared

MassSieve: Panning MS/MS peptide data for proteins

OpenAIRE

Slotta, Douglas J.; McFarland, Melinda A.; Markey, Sanford P.

2010-01-01

We present MassSieve, a Java-based platform for visualization and parsimony analysis of single and comparative LC-MS/MS database search engine results. The success of mass spectrometric peptide sequence assignment algorithms has led to the need for a tool to merge and evaluate the increasing data set sizes that result from LC-MS/MS-based shotgun proteomic experiments. MassSieve supports reports from multiple search engines with differing search characteristics, which can increase peptide sequ...

Quantification of amlodipine and atorvastatin in human plasma by UPLC-MS/MS method and its application to a bioequivalence study.

Science.gov (United States)

Rezk, Mamdouh R; Badr, Kamal A

2018-07-01

A robust, rapid and sensitive UPLC-MS/MS method has been developed, optimized and validated for the determination of amlodipine (AML) and atorvastatin (ATO) in human plasma using eplerenone as an internal standard (IS). Multiple-reaction monitoring in positive electrospray ionization mode was utilized in Xevo TQD LC-MS/MS. Double extraction was used in sample preparation using diethyl ether and ethyl acetate. The prepared samples were analyzed using an Acquity UPLC BEH C 18 (50 × 2.1 mm, 1.7 μm) column. Ammonium formate and acetonitrile, pumped isocraticaly at a flow rate of 0.25 mL/min, were used as a mobile phase. Method validation was done as per the US Food and Drug Administration guidelines. Linearity was achieved in the range of 0.1-10 ng/mL for AML and 0.05-50 ng/mL for ATO. Intra-day and inter-day accuracy and precision were calculated and found to be within the acceptable range. A short run time, of <1.5 min, permits analysis of a large number of plasma samples per batch. The developed and validated method was applied to estimate AML and ATO in a bioequivalence study in healthy human volunteers. Copyright © 2018 John Wiley & Sons, Ltd.

Identification and characterization of novel long-term metabolites of oxymesterone and mesterolone in human urine by application of selected reaction monitoring GC-CI-MS/MS.

Science.gov (United States)

Polet, Michael; Van Gansbeke, Wim; Geldof, Lore; Deventer, Koen; Van Eenoo, Peter

2017-11-01

The search for metabolites with longer detection times remains an important task in, for example, toxicology and doping control. The impact of these long-term metabolites is highlighted by the high number of positive cases after reanalysis of samples that were stored for several years, e.g. samples of previous Olympic Games. A substantial number of previously alleged negative samples have now been declared positive due to the detection of various long-term steroid metabolites the existence of which was unknown during the Olympic Games of 2008 and 2012. In this work, the metabolism of oxymesterone and mesterolone, two anabolic androgenic steroids (AAS), was investigated by application of a selected reaction monitoring gas chromatography-chemical ionization-triple quadrupole mass spectrometry (GC-CI-MS/MS) protocol for metabolite detection and identification. Correlations between AAS structure and GC-CI-MS/MS fragmentation behaviour enabled the search for previously unknown but expected AAS metabolites by selection of theoretical transitions for expected metabolites. Use of different hydrolysis protocols allowed for evaluation of the detection window of both phase I and phase II metabolites. For oxymesterone, a new metabolite, 18-nor-17β-hydroxymethyl-17α-methyl-4-hydroxy-androst-4,13-diene-3-one, was identified. It was detectable up to 46 days by using GC-CI-MS/MS, whereas with a traditional screening (detection of metabolite 17-epioxymesterone with electron ionization GC-MS/MS) oxymesterone administration was only detectable for 3.5 days. A new metabolite was also found for mesterolone. It was identified as 1α-methyl-5α-androstan-3,6,16-triol-17-one and its sulfate form after hydrolysis with Helix pomatia resulted in a prolonged detection time (up to 15 days) for mesterolone abuse. Copyright © 2017 John Wiley & Sons, Ltd. Copyright © 2017 John Wiley & Sons, Ltd.

Design of Ru(II) sensitizers endowed by three anchoring units for adsorption mode and light harvesting optimization

International Nuclear Information System (INIS)

Lobello, Maria Grazia; Fantacci, Simona; Manfredi, Norberto; Coluccini, Carmine; Abbotto, Alessandro; Nazeeruddin, Mohammed K.; De Angelis, Filippo

2014-01-01

We report the design, synthesis and computational investigation of a class of Ru(II)-dyes based on mixed bipyridine ligands for use in dye-sensitized solar cells. These dyes are designed to preserve the optimal anchoring mode of the prototypical N719 sensitizer by three carboxylic groups, yet allowing for tunable optimization of their electronic and optical properties by selective substitution at one of the 4-4′ positions of a single bipyridine ligand with π-excessive heteroaromatic groups. We used Density Functional Theory/Time Dependent Density Functional Theory calculations to analyze the electronic structure and optical properties of the dye and to investigate the dye adsorption mode on a TiO 2 nanoparticle model. Our results show that we are effectively able to introduce three carboxylic anchoring units into the dye and achieve at the same time an enhanced dye light harvesting, demonstrating the design concept. As a drawback of this type of dyes, the synthesis leads to a mixture of dye isomers, which are rather tedious to separate. - Highlights: • We designed heteroleptic Ru(II) sensitizers with three carboxylic anchoring groups. • The three carboxylic anchoring groups are essential for high open circuit potentials. • Introduction of the mixed bipyridine ligand increases the dye light absorption. • Computational simulations confirm the three anchoring sites on TiO 2

Design of Ru(II) sensitizers endowed by three anchoring units for adsorption mode and light harvesting optimization

Energy Technology Data Exchange (ETDEWEB)

Lobello, Maria Grazia; Fantacci, Simona [Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari, Via elce di Sotto 8, I-06213 Perugia (Italy); Manfredi, Norberto; Coluccini, Carmine [Department of Materials Science and Milano-Bicocca Solar Energy Research Center-MIB-Solar, University of Milano-Bicocca and INSTM, Via Cozzi 53, I-20125 Milano (Italy); Abbotto, Alessandro, E-mail: alessandro.abbotto@unimib.it [Department of Materials Science and Milano-Bicocca Solar Energy Research Center-MIB-Solar, University of Milano-Bicocca and INSTM, Via Cozzi 53, I-20125 Milano (Italy); Nazeeruddin, Mohammed K., E-mail: mdkhaja.nazeeruddin@epfl.ch [Laboratory for Photonics and Interfaces, Station 6, Institute of Chemical Sciences and Engineering, School of Basic Sciences, Swiss Federal Institute of Technology, CH-1015 Lausanne (Switzerland); De Angelis, Filippo, E-mail: filippo@thch.unipg.it [Computational Laboratory for Hybrid/Organic Photovoltaics (CLHYO), Istituto CNR di Scienze e Tecnologie Molecolari, Via elce di Sotto 8, I-06213 Perugia (Italy)

2014-06-02

We report the design, synthesis and computational investigation of a class of Ru(II)-dyes based on mixed bipyridine ligands for use in dye-sensitized solar cells. These dyes are designed to preserve the optimal anchoring mode of the prototypical N719 sensitizer by three carboxylic groups, yet allowing for tunable optimization of their electronic and optical properties by selective substitution at one of the 4-4′ positions of a single bipyridine ligand with π-excessive heteroaromatic groups. We used Density Functional Theory/Time Dependent Density Functional Theory calculations to analyze the electronic structure and optical properties of the dye and to investigate the dye adsorption mode on a TiO{sub 2} nanoparticle model. Our results show that we are effectively able to introduce three carboxylic anchoring units into the dye and achieve at the same time an enhanced dye light harvesting, demonstrating the design concept. As a drawback of this type of dyes, the synthesis leads to a mixture of dye isomers, which are rather tedious to separate. - Highlights: • We designed heteroleptic Ru(II) sensitizers with three carboxylic anchoring groups. • The three carboxylic anchoring groups are essential for high open circuit potentials. • Introduction of the mixed bipyridine ligand increases the dye light absorption. • Computational simulations confirm the three anchoring sites on TiO{sub 2}.

Development of a chromatographic separation method hyphenated to electro-spray ionization mass spectrometry (ESI-MS) and inductively coupled plasma mass spectrometry (ICP-MS): application to the lanthanides speciation analysis

International Nuclear Information System (INIS)

Beuvier, Ludovic

2015-01-01

This work focuses on the development of a chromatographic separation method coupled to both ESI-MS and ICP-MS in order to achieve the comprehensive speciation analysis of lanthanides in aqueous phase representative of back-extraction phases of advanced spent nuclear fuel treatment processes. This analytical method allowed the separation, the characterization and the quantitation of lanthanides complexes holding poly-aminocarboxylic ligands, such as DTPA and EDTA, used as complexing agents in these processes. A HILIC separation method of lanthanides complexes has been developed with an amide bonded stationary phase. A screening of a wide range of mobile phase compositions demonstrated that the adsorption mechanism was predominant. This screening allowed also obtaining optimized separation conditions. Faster analysis conditions with shorter amide column packed with sub 2 μm particles reduced analysis time by 2.5 and 25% solvent consumption. Isotopic and structural characterization by HILIC ESI-MS was performed as well as the development of external calibration quantitation method. Analytical performances of quantitation method were determined. Finally, the development of the HILIC coupling to ESI-MS and ICP-MS was achieved. A simultaneous quantitation method by ESI-MS and ICP-MS was performed to determine the species quantitative distribution in solution. Analytical performances of quantitation method were also determined. (author) [fr

A Scheduling Model for the Re-entrant Manufacturing System and Its Optimization by NSGA-II

Directory of Open Access Journals (Sweden)

Masoud Rabbani

2016-11-01

Full Text Available In this study, a two-objective mixed-integer linear programming model (MILP for multi-product re-entrant flow shop scheduling problem has been designed. As a result, two objectives are considered. One of them is maximization of the production rate and the other is the minimization of processing time. The system has m stations and can process several products in a moment. The re-entrant flow shop scheduling problem is well known as NP-hard problem and its complexity has been discussed by several researchers. Given that NSGA-II algorithm is one of the strongest and most applicable algorithm in solving multi-objective optimization problems, it is used to solve this problem. To increase algorithm performance, Taguchi technique is used to design experiments for algorithm’s parameters. Numerical experiments are proposed to show the efficiency and effectiveness of the model. Finally, the results of NSGA-II are compared with SPEA2 algorithm (Strength Pareto Evolutionary Algorithm 2. The experimental results show that the proposed algorithm performs significantly better than the SPEA2.

Solid Phase Extraction of Trace Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) Ions in Beverages on Functionalized Polymer Microspheres Prior to Flame Atomic Absorption Spectrometric Determinations.

Science.gov (United States)

Berber, Hale; Alpdogan, Güzin

2017-01-01

In this study, poly(glycidyl methacrylate-methyl methacrylate-divinylbenzene) was synthesized in the form of microspheres, and then functionalized by 2-aminobenzothiazole ligand. The sorption properties of these functionalized microspheres were investigated for separation, preconcentration and determination of Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) ions using flame atomic absorption spectrometry. The optimum pH values for quantitative sorption were 2 - 4, 5 - 8, 6 - 8, 4 - 6, 2 - 6 and 2 - 3 for Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II), respectively, and also the highest sorption capacity of the functionalized microspheres was found to be for Cu(II) with the value of 1.87 mmol g -1 . The detection limits (3σ; N = 6) obtained for the studied metals in the optimal conditions were observed in the range of 0.26 - 2.20 μg L -1 . The proposed method was successfully applied to different beverage samples for the determination of Al(III), Fe(II), Co(II), Cu(II), Cd(II) and Pb(II) ions, with the relative standard deviation of <3.7%.

Relapsing-Remitting MS (RRMS)

Medline Plus

Full Text Available ... Area Donate Donate Search v What Is MS? Definition of MS What Causes MS? Who Gets MS? ... Support Personal Stories d What Is MS? d Definition of MS Myelin Immune-Mediated Disease T Cells ...

Metabolic profiling of roots of liquorice (Glycyrrhiza glabra) from different geographical areas by ESI/MS/MS and determination of major metabolites by LC-ESI/MS and LC-ESI/MS/MS.

Science.gov (United States)

Montoro, Paola; Maldini, Mariateresa; Russo, Mariateresa; Postorino, Santo; Piacente, Sonia; Pizza, Cosimo

2011-02-20

Liquid chromatography electrospray mass spectrometry (LC-ESI/MS) has been applied to the full characterization of saponins and phenolics in hydroalcoholic extracts of roots of liquorice (Glycyrrhiza glabra). Relative quantitative analyses of the samples with respect to the phenolic constituents and to a group of saponins related to glycyrrhizic acid were performed using LC-ESI/MS. For the saponin constituents, full scan LC-MS/MS fragmentation of the protonated (positive ion mode) or deprotonated (negative ion mode) molecular species generated diagnostic fragment ions that provided information concerning the triterpene skeleton and the number and nature of the substituents. On the basis of the specific fragmentation of glycyrrhizic acid, an LC-MS/MS method was developed in order to quantify the analyte in the liquorice root samples. Chinese G. glabra roots contained the highest levels of glycyrrhizic acid, followed by those from Italy (Calabria). Copyright © 2010 Elsevier B.V. All rights reserved.

Development and Validation of a UPLC-MS/MS and UPLC-HR-MS Method for the Determination of Fumonisin B1 and Its Hydrolysed Metabolites and Fumonisin B2 in Broiler Chicken Plasma

Directory of Open Access Journals (Sweden)

Siegrid De Baere

2018-01-01

Full Text Available A sensitive and specific method for the quantitative determination of Fumonisin B1 (FB1, its partially hydrolysed metabolites pHFB1a+b and hydrolysed metabolite HFB1, and Fumonisin B2 (FB2 in broiler chicken plasma using ultra-performance liquid chromatography combined with tandem mass spectrometry (UPLC-MS/MS was developed. The sample preparation was rapid, straightforward and consisted of a deproteinization and phospholipid removal step using an Oasis® OstroTM 96-well plate. Chromatography was performed on an Acquity HSS-T3 column, using 0.3% formic acid and 10 mM ammonium formate in water, and acetonitrile as mobile phases. The MS/MS instrument was operated in the positive electrospray ionization mode and the two multiple reaction monitoring transitions were monitored for each component for quantification and identification, respectively. The method was validated in-house: matrix-matched calibration graphs were prepared and good linearity (r ≥ 0.99 was achieved over the concentration ranges tested (1–500 ng/mL for FB1 and FB2; 0.86–860 ng/mL for pHFB1a; 0.72–1430 ng/mL for pHFB1b and 2.5–2500 ng/mL for HFB1. Limits of quantification (LOQ and detection (LOD in plasma ranged between 0.72 to 2.5 ng/mL and 0.03 to 0.17 ng/mL, respectively. The results for the within-day and between-day precision and accuracy fell within the specified ranges. Moreover, the method was transferred to an UPLC high-resolution mass spectrometry (HR-MS instrument in order to determine potential metabolites of HFB1, such as N-acyl-HFB1s and phase II metabolites. The method has been successfully applied to investigate the toxicokinetics and biotransformation of HFB1 in broiler chickens.

Parameter optimization for reproducible cardiac 1 H-MR spectroscopy at 3 Tesla.

Science.gov (United States)

de Heer, Paul; Bizino, Maurice B; Lamb, Hildo J; Webb, Andrew G

2016-11-01

To optimize data acquisition parameters in cardiac proton MR spectroscopy, and to evaluate the intra- and intersession variability in myocardial triglyceride content. Data acquisition parameters at 3 Tesla (T) were optimized and reproducibility measured using, in total, 49 healthy subjects. The signal-to-noise-ratio (SNR) and the variance in metabolite amplitude between averages were measured for: (i) global versus local power optimization; (ii) static magnetic field (B 0 ) shimming performed during free-breathing or within breathholds; (iii) post R-wave peak measurement times between 50 and 900 ms; (iv) without respiratory compensation, with breathholds and with navigator triggering; and (v) frequency selective excitation, Chemical Shift Selective (CHESS) and Multiply Optimized Insensitive Suppression Train (MOIST) water suppression techniques. Using the optimized parameters intra- and intersession myocardial triglyceride content reproducibility was measured. Two cardiac proton spectra were acquired with the same parameters and compared (intrasession reproducibility) after which the subject was removed from the scanner and placed back in the scanner and a third spectrum was acquired which was compared with the first measurement (intersession reproducibility). Local power optimization increased SNR on average by 22% compared with global power optimization (P = 0.0002). The average linewidth was not significantly different for pencil beam B 0 shimming using free-breathing or breathholds (19.1 Hz versus 17.5 Hz; P = 0.15). The highest signal stability occurred at a cardiac trigger delay around 240 ms. The mean amplitude variation was significantly lower for breathholds versus free-breathing (P = 0.03) and for navigator triggering versus free-breathing (P = 0.03) as well as for navigator triggering versus breathhold (P = 0.02). The mean residual water signal using CHESS (1.1%, P = 0.01) or MOIST (0.7%, P = 0.01) water suppression was significantly lower than using

GC-MS quantitation of fragrance compounds suspected to cause skin reactions. 1.

Science.gov (United States)

Chaintreau, Alain; Joulain, Daniel; Marin, Christophe; Schmidt, Claus-Oliver; Vey, Matthias

2003-10-22

Recent changes in European legislation require monitoring of 24 volatile compounds in perfumes as they might elicit skin sensitization. This paper reports a GC-MS quantitation procedure for their determination in fragrance concentrates. GC and MS conditions were optimized for a routine use: analysis within 30 min, solvent and internal standard selection, and stock solution stability. Calibration curves were linear in the range of 2-100 mg/L with coefficients of determination in excess of 0.99. The method was tested using real perfumes spiked with known amounts of reference compounds.

Separation of corticosteroids by microemulsion EKC with diethyl L-tartrate as the oil phase.

Science.gov (United States)

Wu, Chi-Hung; Chen, Tse-Hsien; Huang, Kuan-Pin; Wang, Guan-Ren; Liu, Chuen-Ying

2007-10-01

A novel microemulsion based on a mixture of diethyl L-tartrate (DET) and SDS was developed for the microemulsion EKC (MEEKC) determination of structurally related steroids. The system consisted of 0.5% w/w DET, 1.7% w/w SDS, 1.2% w/w 1-butanol, 89.6% w/w phosphate buffer (40 mM, pH 7.0), and 7% w/w ACN. With an applied voltage of +10 kV, a baseline separation of aldosterone (A), cortisone acetate (CA), dexamethasone (D), hydrocortisone (H), hydrocortisone acetate (HA), prednisolone (P), prednisolone acetate (PA), prednisone (Ps), triamcinolone (T), and triamcinolone acetonide (TA) could be achieved. Under the optimized conditions, the reproducibility of the retention time (n = 4) for most of the compounds was less than +/-0.8% with the exception of A, Ps, and T. The average number of theoretical plates was 18 800 plates/m. The results were compared with those achieved by the modified micellar EKC (MEKC). MEEKC showed obvious advantages over MEKC for the separation of highly hydrophobic substances. To further evaluate the system, we tested the MEEKC method by analyzing corticosteroids in a spiked urine sample.

Dopamine, T cells and multiple sclerosis (MS).

Science.gov (United States)

Levite, Mia; Marino, Franca; Cosentino, Marco

2017-05-01

Dopamine is a key neurotransmitter that induces critical effects in the nervous system and in many peripheral organs, via 5 dopamine receptors (DRs): D1R-D5R. Dopamine also induces many direct and very potent effects on many DR-expressing immune cells, primarily T cells and dendritic cells. In this review, we focus only on dopamine receptors, effects and production in T cells. Dopamine by itself (at an optimal concentration of~0.1 nM) induces multiple function of resting normal human T cells, among them: T cell adhesion, chemotactic migration, homing, cytokine secretion and others. Interestingly, dopamine activates resting effector T cells (Teffs), but suppresses regulatory T cells (Tregs), and both effects lead eventually to Teff activation. Dopamine-induced effects on T cells are dynamic, context-sensitive and determined by the: T cell activation state, T cell type, DR type, and dopamine concentration. Dopamine itself, and also few dopaminergic molecules/ drugs that are in clinical use for cardiac, neurological and other non-immune indications, have direct effects on human T cells (summarized in this review). These dopaminergic drugs include: dopamine = intropin, L-DOPA, bromocriptine, pramipexole, pergolide, haloperidol, pimozide, and amantadine. Other dopaminergic drugs were not yet tested for their direct effects on T cells. Extensive evidence in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE) show dopaminergic dysregulations in T cells in these diseases: D1-like DRs are decreased in Teffs of MS patients, and dopamine does not affect these cells. In contrast, D1-like DRs are increased in Tregs of MS patients, possibly causing functional Treg impairment in MS. Treatment of MS patients with interferon β (IFN-β) increases D1-like DRs and decreases D2-like DRs in Teffs, decreases D1-like DRs in Tregs, and most important: restores responsiveness of patient's Teffs to dopamine. DR agonists and antagonists confer some benefits in

Ultrasound-assisted xanthation of cellulose from lignocellulosic biomass optimized by response surface methodology for Pb(II) sorption.

Science.gov (United States)

Wang, Chongqing; Wang, Hui; Gu, Guohua

2018-02-15

Alkali treatment of lignocellulosic biomass is conducted to remove hemi-cellulose and lignin, further increasing the reactivity and accessibility of cellulose. Ultrasound-assisted xanthation of alkali cellulose is optimized by response surface methodology (RSM) with a Box-Behnken design. A predicting mathematical model is obtained by fitting experimental data, and it is verified by analysis of variance. Response surface plots and the contour plots obtained from the model are applied to determine the interactions of experimental variables. The optimum conditions are NaOH concentration 1.3mol/L, ultrasonic time 71.6min and CS 2 dosage 1.5mL. FTIR, SEM and XPS characterizations confirm the synthesis and sorption mechanism of cellulose xanthate (CX). Biosorption of Pb (II) onto CX obeys pseudo-second order model and Langmuir model. The sorption mechanism is attributed to surface complexation or ion exchange. CX shows good reusability for Pb (II) sorption. The maximum sorption capacity of Pb(II) is 134.41mg/g, higher than that of other biosorbents. CX has great potential as an efficient and low-cost biosorbent for wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

Design optimization of axial flow hydraulic turbine runner: Part II - multi-objective constrained optimization method

Science.gov (United States)

Peng, Guoyi; Cao, Shuliang; Ishizuka, Masaru; Hayama, Shinji

2002-06-01

This paper is concerned with the design optimization of axial flow hydraulic turbine runner blade geometry. In order to obtain a better design plan with good performance, a new comprehensive performance optimization procedure has been presented by combining a multi-variable multi-objective constrained optimization model with a Q3D inverse computation and a performance prediction procedure. With careful analysis of the inverse design of axial hydraulic turbine runner, the total hydraulic loss and the cavitation coefficient are taken as optimization objectives and a comprehensive objective function is defined using the weight factors. Parameters of a newly proposed blade bound circulation distribution function and parameters describing positions of blade leading and training edges in the meridional flow passage are taken as optimization variables.The optimization procedure has been applied to the design optimization of a Kaplan runner with specific speed of 440 kW. Numerical results show that the performance of designed runner is successfully improved through optimization computation. The optimization model is found to be validated and it has the feature of good convergence. With the multi-objective optimization model, it is possible to control the performance of designed runner by adjusting the value of weight factors defining the comprehensive objective function. Copyright

Optimal platform design using non-dominated sorting genetic algorithm II and technique for order of preference by similarity to ideal solution; application to automotive suspension system

Science.gov (United States)

Shojaeefard, Mohammad Hassan; Khalkhali, Abolfazl; Faghihian, Hamed; Dahmardeh, Masoud

2018-03-01

Unlike conventional approaches where optimization is performed on a unique component of a specific product, optimum design of a set of components for employing in a product family can cause significant reduction in costs. Increasing commonality and performance of the product platform simultaneously is a multi-objective optimization problem (MOP). Several optimization methods are reported to solve these MOPs. However, what is less discussed is how to find the trade-off points among the obtained non-dominated optimum points. This article investigates the optimal design of a product family using non-dominated sorting genetic algorithm II (NSGA-II) and proposes the employment of technique for order of preference by similarity to ideal solution (TOPSIS) method to find the trade-off points among the obtained non-dominated results while compromising all objective functions together. A case study for a family of suspension systems is presented, considering performance and commonality. The results indicate the effectiveness of the proposed method to obtain the trade-off points with the best possible performance while maximizing the common parts.

Experiment, modeling and optimization of liquid phase adsorption of Cu(II) using dried and carbonized biomass of Lyngbya majuscula

Science.gov (United States)

Kushwaha, Deepika; Dutta, Susmita

2017-05-01

The present work aims at evaluation of the potential of cyanobacterial biomass to remove Cu(II) from simulated wastewater. Both dried and carbonized forms of Lyngbya majuscula, a cyanobacterial strain, have been used for such purpose. The influences of different experimental parameters viz., initial Cu(II) concentration, solution pH and adsorbent dose have been examined on sorption of Cu(II). Kinetic and equilibrium studies on Cu(II) removal from simulated wastewater have been done using both dried and carbonized biomass individually. Pseudo-second-order model and Langmuir isotherm have been found to fit most satisfactorily to the kinetic and equilibrium data, respectively. Maximum 87.99 and 99.15 % of Cu(II) removal have been achieved with initial Cu(II) concentration of 10 and 25 mg/L for dried and carbonized algae, respectively, at an adsorbent dose of 10 g/L for 20 min of contact time and optimum pH 6. To optimize the removal process, Response Surface Methodology has been employed using both the dried and carbonized biomass. Removal with initial Cu(II) concentration of 20 mg/L, with 0.25 g adsorbent dose in 50 mL solution at pH 6 has been found to be optimum with both the adsorbents. This is the first ever attempt to make a comparative study on Cu(II) removal using both dried algal biomass and its activated carbon. Furthermore, regeneration of matrix was attempted and more than 70% and 80% of the adsorbent has been regenerated successfully in the case of dried and carbonized biomass respectively upto the 3rd cycle of regeneration study.

Eco-friendly LC-MS/MS method for analysis of multi-class micropollutants in tap, fountain, and well water from northern Portugal.

Science.gov (United States)

Barbosa, Marta O; Ribeiro, Ana R; Pereira, Manuel F R; Silva, Adrián M T

2016-11-01

Organic micropollutants present in drinking water (DW) may cause adverse effects for public health, and so reliable analytical methods are required to detect these pollutants at trace levels in DW. This work describes the first green analytical methodology for multi-class determination of 21 pollutants in DW: seven pesticides, an industrial compound, 12 pharmaceuticals, and a metabolite (some included in Directive 2013/39/EU or Decision 2015/495/EU). A solid-phase extraction procedure followed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry (offline SPE-UHPLC-MS/MS) method was optimized using eco-friendly solvents, achieving detection limits below 0.20 ng L -1 . The validated analytical method was successfully applied to DW samples from different sources (tap, fountain, and well waters) from different locations in the north of Portugal, as well as before and after bench-scale UV and ozonation experiments in spiked tap water samples. Thirteen compounds were detected, many of them not regulated yet, in the following order of frequency: diclofenac > norfluoxetine > atrazine > simazine > warfarin > metoprolol > alachlor > chlorfenvinphos > trimethoprim > clarithromycin ≈ carbamazepine ≈ PFOS > citalopram. Hazard quotients were also estimated for the quantified substances and suggested no adverse effects to humans. Graphical Abstract Occurrence and removal of multi-class micropollutants in drinking water, analyzed by an eco-friendly LC-MS/MS method.

Optimization, isotherm, kinetic and thermodynamic studies of Pb(II) ions adsorption onto N-maleated chitosan-immobilized TiO2 nanoparticles from aqueous media

Science.gov (United States)

Shaker, Medhat A.; Yakout, Amr A.

2016-02-01

Chitosan, CS was chemically engineered by maleic anhydride via simple protocol to produce N-maleated chitosan, MCS which immobilized on anatase TiO2 to synthesize novel eco-friendly nanosorbent (51 ± 3.8 nm), MCS@TiO2 for cost-effective and efficient removal of Pb(II) ions from aqueous media. The chemical structure, surface properties and morphology of MCS@TiO2 were recognized by FTIR, 1H NMR, XRD, TEM, DLS and zeta-potential techniques. The relations between %removal of Pb(II) and different analytical parameters such as solution acidity (pH), MCS@TiO2 dosage, time of contact and initial Pb(II) concentration were optimized using response surface methodology (RSM) and Box-Behnken design (BBD) statistical procedures. The fitting of the experimental data to four different isotherm models at optimized conditions was carried out by various statistical treatments including the correlation coefficient (r), coefficient of determination (r2) and non-linear Chi-square (χ2) test analyses which all confirm the suitability of Langmuir model to explain the adsorption isotherm data. Also, statistics predicted that the pseudo-second-order model is the optimum kinetic model among four applied kinetic models to closely describe the rate equation of the adsorption process. Thermodynamics viewed the adsorption as endothermic and feasible physical process. EDTA could release the sorbed Pb(II) ions from MCS@TiO2 with a recovery above 92% after three sorption-desorption cycles. The novel synthesized nanosorbent is evidenced to be an excellent solid phase extractor for Pb(II) ions from wastewaters.

Multielemental speciation analysis by advanced hyphenated technique - HPLC/ICP-MS: A review.

Science.gov (United States)

Marcinkowska, Monika; Barałkiewicz, Danuta

2016-12-01

Speciation analysis has become an invaluable tool in human health risk assessment, environmental monitoring or food quality control. Another step is to develop reliable multielemental speciation methodologies, to reduce costs, waste and time needed for the analysis. Separation and detection of species of several elements in a single analytical run can be accomplished by high performance liquid chromatography hyphenated to inductively coupled plasma mass spectrometry (HPLC/ICP-MS). Our review assembles articles concerning multielemental speciation determination of: As, Se, Cr, Sb, I, Br, Pb, Hg, V, Mo, Te, Tl, Cd and W in environmental, biological, food and clinical samples analyzed with HPLC/ICP-MS. It addresses the procedures in terms of following issues: sample collection and pretreatment, selection of optimal conditions for elements species separation by HPLC and determination using ICP-MS as well as metrological approach. The presented work is the first review article concerning multielemental speciation analysis by advanced hyphenated technique HPLC/ICP-MS. Copyright © 2016 Elsevier B.V. All rights reserved.

Analysis of poly-beta-hydroxybutyrate in environmental samples by GC-MS/MS.

Science.gov (United States)

Elhottová, D; Tríska, J; Petersen, S O; Santrůcková, H

2000-05-01

Application of gas chromatography-mass spectrometry (GC-MS) can significantly improve trace analyses of compounds in complex matrices from natural environments compared to gas chromatography only. A GC-MS/MS technique for determination of poly-beta-hydroxybutyrate (PHB), a bacterial storage compound, has been developed and used for analysis of two soils stored for up to 319 d, fresh samples of sewage sludge, as well as a pure culture of Bacillus megaterium. Specific derivatization of beta-hydroxybutyrate (3-OH C4:0) PHB monomer units by N-tert-butyl-dimethylsilyl-N-methyltrifluoracetamide (MTBSTFA) improved chromatographic and mass spectrometric properties of the analyte. The diagnostic fragmentation scheme of the derivates tert-butyldimethylsilyl ester and ether of beta-hydroxybutyric acid (MTBSTFA-HB) essential for the PHB identification was shown. The ion trap MS was used, therefore the scan gave the best sensitivity and with MS/MS the noise decreased, so the S/N was better and also with second fragmentation the amount of ions increased compared to SIM. The detection limit for MTBSTFA-HB by GC-MS/MS was about 10(-13) g microL(-1) of injected volume, while by GC (FID) and GC-MS (scan) it was around 10(-10) g microL(-1) of injected volume. Sensitivity of GC-MS/MS measurements of PHB in arable soil and activated sludge samples was down to 10 pg of PHB g(-1) dry matter. Comparison of MTBSTFA-HB detection in natural soil sample by GC (FID), GC-MS (scan) and by GC-MS/MS demonstrated potentials and limitations of the individual measurement techniques.

Optimization and performance evaluation of the microPET II scanner for in vivo small-animal imaging

International Nuclear Information System (INIS)

Yang Yongfeng; Tai Yuanchuan; Siegel, Stefan; Newport, Danny F; Bai, Bing; Li, Quanzheng; Leahy, Richard M; Cherry, Simon R

2004-01-01

MicroPET II is a newly developed PET (positron emission tomography) scanner designed for high-resolution imaging of small animals. It consists of 17 640 LSO crystals each measuring 0.975 x 0.975 x 12.5 mm 3 , which are arranged in 42 contiguous rings, with 420 crystals per ring. The scanner has an axial field of view (FOV) of 4.9 cm and a transaxial FOV of 8.5 cm. The purpose of this study was to carefully evaluate the performance of the system and to optimize settings for in vivo mouse and rat imaging studies. The volumetric image resolution was found to depend strongly on the reconstruction algorithm employed and averaged 1.1 mm (1.4 μl) across the central 3 cm of the transaxial FOV when using a statistical reconstruction algorithm with accurate system modelling. The sensitivity, scatter fraction and noise-equivalent count (NEC) rate for mouse- and rat-sized phantoms were measured for different energy and timing windows. Mouse imaging was optimized with a wide open energy window (150-750 keV) and a 10 ns timing window, leading to a sensitivity of 3.3% at the centre of the FOV and a peak NEC rate of 235 000 cps for a total activity of 80 MBq (2.2 mCi) in the phantom. Rat imaging, due to the higher scatter fraction, and the activity that lies outside of the field of view, achieved a maximum NEC rate of 24 600 cps for a total activity of 80 MBq (2.2 mCi) in the phantom, with an energy window of 250-750 keV and a 6 ns timing window. The sensitivity at the centre of the FOV for these settings is 2.1%. This work demonstrates that different scanner settings are necessary to optimize the NEC count rate for different-sized animals and different injected doses. Finally, phantom and in vivo animal studies are presented to demonstrate the capabilities of microPET II for small-animal imaging studies

Ranking Fragment Ions Based on Outlier Detection for Improved Label-Free Quantification in Data-Independent Acquisition LC-MS/MS

Science.gov (United States)

Bilbao, Aivett; Zhang, Ying; Varesio, Emmanuel; Luban, Jeremy; Strambio-De-Castillia, Caterina; Lisacek, Frédérique; Hopfgartner, Gérard

2016-01-01

Data-independent acquisition LC-MS/MS techniques complement supervised methods for peptide quantification. However, due to the wide precursor isolation windows, these techniques are prone to interference at the fragment ion level, which in turn is detrimental for accurate quantification. The “non-outlier fragment ion” (NOFI) ranking algorithm has been developed to assign low priority to fragment ions affected by interference. By using the optimal subset of high priority fragment ions these interfered fragment ions are effectively excluded from quantification. NOFI represents each fragment ion as a vector of four dimensions related to chromatographic and MS fragmentation attributes and applies multivariate outlier detection techniques. Benchmarking conducted on a well-defined quantitative dataset (i.e. the SWATH Gold Standard), indicates that NOFI on average is able to accurately quantify 11-25% more peptides than the commonly used Top-N library intensity ranking method. The sum of the area of the Top3-5 NOFIs produces similar coefficients of variation as compared to the library intensity method but with more accurate quantification results. On a biologically relevant human dendritic cell digest dataset, NOFI properly assigns low priority ranks to 85% of annotated interferences, resulting in sensitivity values between 0.92 and 0.80 against 0.76 for the Spectronaut interference detection algorithm. PMID:26412574

Optimal dose selection accounting for patient subpopulations in a randomized Phase II trial to maximize the success probability of a subsequent Phase III trial.

Science.gov (United States)

Takahashi, Fumihiro; Morita, Satoshi

2018-02-08

Phase II clinical trials are conducted to determine the optimal dose of the study drug for use in Phase III clinical trials while also balancing efficacy and safety. In conducting these trials, it may be important to consider subpopulations of patients grouped by background factors such as drug metabolism and kidney and liver function. Determining the optimal dose, as well as maximizing the effectiveness of the study drug by analyzing patient subpopulations, requires a complex decision-making process. In extreme cases, drug development has to be terminated due to inadequate efficacy or severe toxicity. Such a decision may be based on a particular subpopulation. We propose a Bayesian utility approach (BUART) to randomized Phase II clinical trials which uses a first-order bivariate normal dynamic linear model for efficacy and safety in order to determine the optimal dose and study population in a subsequent Phase III clinical trial. We carried out a simulation study under a wide range of clinical scenarios to evaluate the performance of the proposed method in comparison with a conventional method separately analyzing efficacy and safety in each patient population. The proposed method showed more favorable operating characteristics in determining the optimal population and dose.

Cannabinoids determination in oral fluid by SPME-GC/MS and UHPLC-MS/MS and its application on suspected drivers.

Science.gov (United States)

Anzillotti, Luca; Castrignanò, Erika; Strano Rossi, Sabina; Chiarotti, Marcello

2014-12-01

The confirmation of Δ9-tetrahydrocannabinol (THC) in oral fluid (OF) is an important issue for assessing Driving Under the Influence of Drugs (DUID). The aim of this research was to develop a highly sensitive method with minimal sample pre-treatment suitable for the analysis of small OF volumes (100 μL) for the confirmation of cannabinoids in DUID cases. Two methods were compared for the confirmation of THC in residual OF samples, obtained from a preliminary on-site screening with commercial devices. An ultra high performance LC-MS (UHPLC-MS/MS) method and an SPME-GC/MS method were hence developed. 100 μL of the residual mixture OF/preservative buffer or neat OF was simply added to 10 μL of THC-D3 (1 μg/mL) and submitted to the two different analyses: A - direct injection of 10 μL in UHPLC-MS/MS in positive electrospray ionisation (ESI) mode and B - sampling for 30 min with SPME (100 μm polydimethylsiloxane or PDMS fibre) and direct injection by desorption of the fibre in the GC injection port. The lowest limit of detection (LLOD) of THC was 2 ng/mL in UHPLC-MS/MS and 0.5 ng/mL in SPME-GC/MS. In addition, cannabidiol (CBD) and cannabinol (CBN) could be detected in GC/MS equipment at 2 ng/mL, whilst in UHPLC-MS/MS the LLOD was 20 ng/mL. Both methods were applied to 70 samples coming from roadside tests. By SPME-GC/MS analysis, THC was confirmed in 42 samples, whilst CBD was detected in 21 of them, along with CBN in 14 samples. THC concentrations ranged from traces below the lowest limit of quantification or LLOQ (2 ng/mL) up to 690 ng/mL. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

Software ion scan functions in analysis of glycomic and lipidomic MS/MS datasets.

Science.gov (United States)

Haramija, Marko

2018-03-01

Hardware ion scan functions unique to tandem mass spectrometry (MS/MS) mode of data acquisition, such as precursor ion scan (PIS) and neutral loss scan (NLS), are important for selective extraction of key structural data from complex MS/MS spectra. However, their software counterparts, software ion scan (SIS) functions, are still not regularly available. Software ion scan functions can be easily coded for additional functionalities, such as software multiple precursor ion scan, software no ion scan, and software variable ion scan functions. These are often necessary, since they allow more efficient analysis of complex MS/MS datasets, often encountered in glycomics and lipidomics. Software ion scan functions can be easily coded by using modern script languages and can be independent of instrument manufacturer. Here we demonstrate the utility of SIS functions on a medium-size glycomic MS/MS dataset. Knowledge of sample properties, as well as of diagnostic and conditional diagnostic ions crucial for data analysis, was needed. Based on the tables constructed with the output data from the SIS functions performed, a detailed analysis of a complex MS/MS glycomic dataset could be carried out in a quick, accurate, and efficient manner. Glycomic research is progressing slowly, and with respect to the MS experiments, one of the key obstacles for moving forward is the lack of appropriate bioinformatic tools necessary for fast analysis of glycomic MS/MS datasets. Adding novel SIS functionalities to the glycomic MS/MS toolbox has a potential to significantly speed up the glycomic data analysis process. Similar tools are useful for analysis of lipidomic MS/MS datasets as well, as will be discussed briefly. Copyright © 2017 John Wiley & Sons, Ltd.

Methylation of class II transactivator gene promoter IV is not associated with susceptibility to Multiple Sclerosis

Directory of Open Access Journals (Sweden)

Lincoln Matthew R

2008-07-01

Full Text Available Abstract Background Multiple sclerosis (MS is a complex trait in which alleles at or near the class II loci HLA-DRB1 and HLA-DQB1 contribute significantly to genetic risk. The MHC class II transactivator (MHC2TA is the master controller of expression of class II genes, and methylation of the promoter of this gene has been previously been shown to alter its function. In this study we sought to assess whether or not methylation of the MHC2TA promoter pIV could contribute to MS disease aetiology. Methods In DNA from peripheral blood mononuclear cells from a sample of 50 monozygotic disease discordant MS twins the MHC2TA promoter IV was sequenced and analysed by methylation specific PCR. Results No methylation or sequence variation of the MHC2TA promoter pIV was found. Conclusion The results of this study cannot support the notion that methylation of the pIV promoter of MHC2TA contributes to MS disease risk, although tissue and timing specific epigenetic modifications cannot be ruled out.

Introduction of organic/hydro-organic matrices in inductively coupled plasma optical emission spectrometry and mass spectrometry: A tutorial review. Part II. Practical considerations

Energy Technology Data Exchange (ETDEWEB)

Leclercq, Amélie, E-mail: amelie.leclercq@cea.fr [CEA Saclay, DEN, DANS, DPC, SEARS, Laboratoire de développement Analytique Nucléaire Isotopique et Elémentaire, 91191 Gif-sur-Yvette (France); Nonell, Anthony, E-mail: anthony.nonell@cea.fr [CEA Saclay, DEN, DANS, DPC, SEARS, Laboratoire de développement Analytique Nucléaire Isotopique et Elémentaire, 91191 Gif-sur-Yvette (France); Todolí Torró, José Luis, E-mail: jose.todoli@ua.es [Universidad de Alicante, Departamento de Quimica Analitica, Nutricion y Bromatología, Ap. de Correos, 99, 03080 Alicante (Spain); Bresson, Carole, E-mail: carole.bresson@cea.fr [CEA Saclay, DEN, DANS, DPC, SEARS, Laboratoire de développement Analytique Nucléaire Isotopique et Elémentaire, 91191 Gif-sur-Yvette (France); Vio, Laurent, E-mail: laurent.vio@cea.fr [CEA Saclay, DEN, DANS, DPC, SEARS, Laboratoire de développement Analytique Nucléaire Isotopique et Elémentaire, 91191 Gif-sur-Yvette (France); Vercouter, Thomas, E-mail: thomas.vercouter@cea.fr [CEA Saclay, DEN, DANS, DPC, SEARS, Laboratoire de développement Analytique Nucléaire Isotopique et Elémentaire, 91191 Gif-sur-Yvette (France); Chartier, Frédéric, E-mail: frederic.chartier@cea.fr [CEA Saclay, DEN, DANS, DPC, 91191 Gif-sur-Yvette (France)

2015-07-23

Graphical abstract: This tutorial review is dedicated to the analysis of organic/hydro-organic matrices by ICP techniques. A state-of-the-art focusing on sample introduction, relevant operating parameters optimization and analytical strategies for elemental quantification is provided. - Highlights: • Practical considerations to perform analyses in organic/hydro-organic matrices. • Description, benefits and drawbacks of recent introduction devices. • Optimization to improve plasma tolerance towards organic/hydro-organic matrices. • Analytical strategies for elemental quantification in organic/hydro-organic matrices. - Abstract: Inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are increasingly used to carry out analyses in organic/hydro-organic matrices. The introduction of such matrices into ICP sources is particularly challenging and can be the cause of numerous drawbacks. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP sources. Part I provided theoretical considerations associated with the physico-chemical properties of such matrices, in an attempt to understand the induced phenomena. Part II of this tutorial review is dedicated to more practical considerations on instrumentation, instrumental and operating parameters, as well as analytical strategies for elemental quantification in such matrices. Two important issues are addressed in this part: the first concerns the instrumentation and optimization of instrumental and operating parameters, pointing out (i) the description, benefits and drawbacks of different kinds of nebulization and desolvation devices and the impact of more specific instrumental parameters such as the injector characteristics and the material used for the cone; and, (ii) the optimization of operating parameters, for both ICP-OES and ICP-MS. Even if it is at the margin of this tutorial review

Introduction of organic/hydro-organic matrices in inductively coupled plasma optical emission spectrometry and mass spectrometry: A tutorial review. Part II. Practical considerations

International Nuclear Information System (INIS)

Leclercq, Amélie; Nonell, Anthony; Todolí Torró, José Luis; Bresson, Carole; Vio, Laurent; Vercouter, Thomas; Chartier, Frédéric

2015-01-01

Graphical abstract: This tutorial review is dedicated to the analysis of organic/hydro-organic matrices by ICP techniques. A state-of-the-art focusing on sample introduction, relevant operating parameters optimization and analytical strategies for elemental quantification is provided. - Highlights: • Practical considerations to perform analyses in organic/hydro-organic matrices. • Description, benefits and drawbacks of recent introduction devices. • Optimization to improve plasma tolerance towards organic/hydro-organic matrices. • Analytical strategies for elemental quantification in organic/hydro-organic matrices. - Abstract: Inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are increasingly used to carry out analyses in organic/hydro-organic matrices. The introduction of such matrices into ICP sources is particularly challenging and can be the cause of numerous drawbacks. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP sources. Part I provided theoretical considerations associated with the physico-chemical properties of such matrices, in an attempt to understand the induced phenomena. Part II of this tutorial review is dedicated to more practical considerations on instrumentation, instrumental and operating parameters, as well as analytical strategies for elemental quantification in such matrices. Two important issues are addressed in this part: the first concerns the instrumentation and optimization of instrumental and operating parameters, pointing out (i) the description, benefits and drawbacks of different kinds of nebulization and desolvation devices and the impact of more specific instrumental parameters such as the injector characteristics and the material used for the cone; and, (ii) the optimization of operating parameters, for both ICP-OES and ICP-MS. Even if it is at the margin of this tutorial review

Process optimization and mechanistic studies of lead (II): Aspergillus ...

African Journals Online (AJOL)

The lead (II) accumulation potential of various biosorbent had been widely studied in the last few years, but an outstanding Pb(II) accumulating biomass still seems crucial for bringing the process to a successful application stage. This investigation describes the use of non-living biomass of Aspergillus caespitosus for ...

Development of the HS-SPME-GC-MS/MS method for analysis of chemical warfare agent and their degradation products in environmental samples.

Science.gov (United States)

Nawała, Jakub; Czupryński, Krzysztof; Popiel, Stanisław; Dziedzic, Daniel; Bełdowski, Jacek

2016-08-24

After World War II approximately 50,000 tons of chemical weapons were dumped in the Baltic Sea by the Soviet Union under the provisions of the Potsdam Conference on Disarmament. These dumped chemical warfare agents still possess a major threat to the marine environment and to human life. Therefore, continue monitoring of these munitions is essential. In this work, we present the application of new solid phase microextraction fibers in analysis of chemical warfare agents and their degradation products. It can be concluded that the best fiber for analysis of sulfur mustard and its degradation products is butyl acrylate (BA), whereas for analysis of organoarsenic compounds and chloroacetophenone, the best fiber is a co-polymer of methyl acrylate and methyl methacrylate (MA/MMA). In order to achieve the lowest LOD and LOQ the samples should be divided into two subsamples. One of them should be analyzed using a BA fiber, and the second one using a MA/MMA fiber. When the fast analysis is required, the microextraction should be performed by use of a butyl acrylate fiber because the extraction efficiency of organoarsenic compounds for this fiber is acceptable. Next, we have elaborated of the HS-SPME-GC-MS/MS method for analysis of CWA degradation products in environmental samples using laboratory obtained fibers The analytical method for analysis of organosulfur and organoarsenic compounds was optimized and validated. The LOD's for all target chemicals were between 0.03 and 0.65 ppb. Then, the analytical method developed by us, was used for the analysis of sediment and pore water samples from the Baltic Sea. During these studies, 80 samples were analyzed. It was found that 25 sediments and 5 pore water samples contained CWA degradation products such as 1,4-dithiane, 1,4-oxathiane or triphenylarsine, the latter being a component of arsine oil. The obtained data is evidence that the CWAs present in the Baltic Sea have leaked into the general marine environment. Copyright �

Development of an SPME-GC-MS/MS method for the determination of pesticides in rainwater: Laboratory and field experiments

International Nuclear Information System (INIS)

Sauret-Szczepanski, Nathalie; Mirabel, Philippe; Wortham, Henri

2006-01-01

A solid-phase microextraction - coupled to a gas chromatography - ion trap tandem mass spectrometry (SPME-GC-MS/MS) method was developed for the quantitative determination in rainwater of 8 pesticides amongst the most used in France and 3 triazines metabolites. The main factors affecting the SPME process were studied. Using a 3 mL sample, the method developed showed good linearity for concentrations ranging from 0.05 to 50 μg L -1 with correlation coefficients between 0.997 and 0.9999 and relative standard deviations (% RSD) below 14%. The study of matrix effects showed that rainwater was too diluted to have any significant influence on the extraction efficiency. To validate the method, a field campaign was carried out on the rain events, which occurred in Strasbourg during a one-year period. The rain concentrations showed patterns of high pesticide concentrations during spring months, which were correlated to the spraying periods of most of these substances. - Solid-phase microextraction efficiency of pesticides in rainwater was optimized

Accelerated solvent extraction followed by on-line solid-phase extraction coupled to ion trap LC/MS/MS for analysis of benzalkonium chlorides in sediment samples

Science.gov (United States)

Ferrer, I.; Furlong, E.T.

2002-01-01

Benzalkonium chlorides (BACs) were successfully extracted from sediment samples using a new methodology based on accelerated solvent extraction (ASE) followed by an on-line cleanup step. The BACs were detected by liquid chromatography/ion trap mass spectrometry (LC/MS) or tandem mass spectrometry (MS/MS) using an electrospray interface operated in the positive ion mode. This methodology combines the high efficiency of extraction provided by a pressurized fluid and the high sensitivity offered by the ion trap MS/MS. The effects of solvent type and ASE operational variables, such as temperature and pressure, were evaluated. After optimization, a mixture of acetonitrile/water (6:4 or 7:3) was found to be most efficient for extracting BACs from the sediment samples. Extraction recoveries ranged from 95 to 105% for C12 and C14 homologues, respectively. Total method recoveries from fortified sediment samples, using a cleanup step followed by ASE, were 85% for C12BAC and 79% for C14-BAC. The methodology developed in this work provides detection limits in the subnanogram per gram range. Concentrations of BAC homologues ranged from 22 to 206 ??g/kg in sediment samples from different river sites downstream from wastewater treatment plants. The high affinity of BACs for soil suggests that BACs preferentially concentrate in sediment rather than in water.

Introduction of organic/hydro-organic matrices in inductively coupled plasma optical emission spectrometry and mass spectrometry: a tutorial review. Part II. Practical considerations.

Science.gov (United States)

Leclercq, Amélie; Nonell, Anthony; Todolí Torró, José Luis; Bresson, Carole; Vio, Laurent; Vercouter, Thomas; Chartier, Frédéric

2015-07-23

Inductively coupled plasma optical emission spectrometry (ICP-OES) and mass spectrometry (ICP-MS) are increasingly used to carry out analyses in organic/hydro-organic matrices. The introduction of such matrices into ICP sources is particularly challenging and can be the cause of numerous drawbacks. This tutorial review, divided in two parts, explores the rich literature related to the introduction of organic/hydro-organic matrices in ICP sources. Part I provided theoretical considerations associated with the physico-chemical properties of such matrices, in an attempt to understand the induced phenomena. Part II of this tutorial review is dedicated to more practical considerations on instrumentation, instrumental and operating parameters, as well as analytical strategies for elemental quantification in such matrices. Two important issues are addressed in this part: the first concerns the instrumentation and optimization of instrumental and operating parameters, pointing out (i) the description, benefits and drawbacks of different kinds of nebulization and desolvation devices and the impact of more specific instrumental parameters such as the injector characteristics and the material used for the cone; and, (ii) the optimization of operating parameters, for both ICP-OES and ICP-MS. Even if it is at the margin of this tutorial review, Electrothermal Vaporization and Laser Ablation will also be shortly described. The second issue is devoted to the analytical strategies for elemental quantification in such matrices, with particular insight into the isotope dilution technique, particularly used in speciation analysis by ICP-coupled separation techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Analytical Method Details (MS): SE52_MS01 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available stem and Waters Q-Tof Premier UPLC-QTOF-MS ESI Negative The eluates (3 μl) were subsequently subjected to metabolome...DS column (LC-ESI-Q-Tof/MS, HPLC: Waters Acquity UPLC system; MS: Waters Q-Tof Premier). The metabolome...d (Matsuda et al., 2009c, 2010a). Briefly, the metabolome data were obtained in the negative ion mode (m/z 1... the complex nature of the metabolome data. To construct MS2T libraries, the extracts of five ecotypes were

Optimal cost-effective designs of Phase II proof of concept trials and associated go-no go decisions.

Science.gov (United States)

Chen, Cong; Beckman, Robert A

2009-01-01

This manuscript discusses optimal cost-effective designs for Phase II proof of concept (PoC) trials. Unlike a confirmatory registration trial, a PoC trial is exploratory in nature, and sponsors of such trials have the liberty to choose the type I error rate and the power. The decision is largely driven by the perceived probability of having a truly active treatment per patient exposure (a surrogate measure to development cost), which is naturally captured in an efficiency score to be defined in this manuscript. Optimization of the score function leads to type I error rate and power (and therefore sample size) for the trial that is most cost-effective. This in turn leads to cost-effective go-no go criteria for development decisions. The idea is applied to derive optimal trial-level, program-level, and franchise-level design strategies. The study is not meant to provide any general conclusion because the settings used are largely simplified for illustrative purposes. However, through the examples provided herein, a reader should be able to gain useful insight into these design problems and apply them to the design of their own PoC trials.

Nsls-II Boster

Science.gov (United States)

Gurov, S. M.; Akimov, A. V.; Akimov, V. E.; Anashin, V. V.; Anchugov, O. V.; Baranov, G. N.; Batrakov, A. M.; Belikov, O. V.; Bekhtenev, E. A.; Blum, E.; Bulatov, A. V.; Burenkov, D. B.; Cheblakov, P. B.; Chernyakin, A. D.; Cheskidov, V. G.; Churkin, I. N.; Davidsavier, M.; Derbenev, A. A.; Erokhin, A. I.; Fliller, R. P.; Fulkerson, M.; Gorchakov, K. M.; Ganetis, G.; Gao, F.; Gurov, D. S.; Hseuh, H.; Hu, Y.; Johanson, M.; Kadyrov, R. A.; Karnaev, S. E.; Karpov, G. V.; Kiselev, V. A.; Kobets, V. V.; Konstantinov, V. M.; Kolmogorov, V. V.; Korepanov, A. A.; Kramer, S.; Krasnov, A. A.; Kremnev, A. A.; Kuper, E. A.; Kuzminykh, V. S.; Levichev, E. B.; Li, Y.; Long, J. De; Makeev, A. V.; Mamkin, V. R.; Medvedko, A. S.; Meshkov, O. I.; Nefedov, N. B.; Neyfeld, V. V.; Okunev, I. N.; Ozaki, S.; Padrazo, D.; Petrov, V. V.; Petrichenkov, M. V.; Philipchenko, A. V.; Polyansky, A. V.; Pureskin, D. N.; Rakhimov, A. R.; Rose, J.; Ruvinskiy, S. I.; Rybitskaya, T. V.; Sazonov, N. V.; Schegolev, L. M.; Semenov, A. M.; Semenov, E. P.; Senkov, D. V.; Serdakov, L. E.; Serednyakov, S. S.; Shaftan, T. V.; Sharma, S.; Shichkov, D. S.; Shiyankov, S. V.; Shvedov, D. A.; Simonov, E. A.; Singh, O.; Sinyatkin, S. V.; Smaluk, V. V.; Sukhanov, A. V.; Tian, Y.; Tsukanova, L. A.; Vakhrushev, R. V.; Vobly, P. D.; Utkin, A. V.; Wang, G.; Wahl, W.; Willeke, F.; Yaminov, K. R.; Yong, H.; Zhuravlev, A.; Zuhoski, P.

The National Synchrotron Light Source II is a third generation light source, which was constructed at Brookhaven National Laboratory. This project includes a highly-optimized 3 GeV electron storage ring, linac preinjector, and full-energy synchrotron injector. Budker Institute of Nuclear Physics built and delivered the booster for NSLS-II. The commissioning of the booster was successfully completed. This paper reviews fulfilled work by participants.

Implementation of the cost-optimal methodology according to the EPBD recast

DEFF Research Database (Denmark)

Wittchen, Kim Bjarne; Thomsen, Kirsten Engelund

2012-01-01

The EPBD recast states that Member States (MS) must ensure that minimum energy performance requirements for buildings are set “with a view to achieving cost-optimal levels”. The costoptimal level must be calculated in accordance with a comparative methodology.......The EPBD recast states that Member States (MS) must ensure that minimum energy performance requirements for buildings are set “with a view to achieving cost-optimal levels”. The costoptimal level must be calculated in accordance with a comparative methodology....

Multi-objective optimization of combustion, performance and emission parameters in a jatropha biodiesel engine using Non-dominated sorting genetic algorithm-II

Science.gov (United States)

Dhingra, Sunil; Bhushan, Gian; Dubey, Kashyap Kumar

2014-03-01

The present work studies and identifies the different variables that affect the output parameters involved in a single cylinder direct injection compression ignition (CI) engine using jatropha biodiesel. Response surface methodology based on Central composite design (CCD) is used to design the experiments. Mathematical models are developed for combustion parameters (Brake specific fuel consumption (BSFC) and peak cylinder pressure (Pmax)), performance parameter brake thermal efficiency (BTE) and emission parameters (CO, NO x , unburnt HC and smoke) using regression techniques. These regression equations are further utilized for simultaneous optimization of combustion (BSFC, Pmax), performance (BTE) and emission (CO, NO x , HC, smoke) parameters. As the objective is to maximize BTE and minimize BSFC, Pmax, CO, NO x , HC, smoke, a multiobjective optimization problem is formulated. Nondominated sorting genetic algorithm-II is used in predicting the Pareto optimal sets of solution. Experiments are performed at suitable optimal solutions for predicting the combustion, performance and emission parameters to check the adequacy of the proposed model. The Pareto optimal sets of solution can be used as guidelines for the end users to select optimal combination of engine output and emission parameters depending upon their own requirements.

Design and verification of controllers for longitudinal oscillations using optimal control theory and numerical simulation: Predictions for PEP-II

International Nuclear Information System (INIS)

Hindi, H.; Prabhakar, S.; Fox, J.; Teytelman, D.

1997-12-01

The authors present a technique for the design and verification of efficient bunch-by-bunch controllers for damping longitudinal multibunch instabilities. The controllers attempt to optimize the use of available feedback amplifier power--one of the most expensive components of a feedback system--and define the limits of closed loop system performance. The design technique alternates between analytic computation of single bunch optimal controllers and verification on a multibunch numerical simulator. The simulator identifies unstable coupled bunch modes and predicts their growth and damping rates. The results from the simulator are shown to be in reasonable agreement with analytical calculations based on the single bunch model. The technique is then used to evaluate the performance of a variety of controllers proposed for PEP-II

Chiral separation of amino acids in biological fluids by micellar electrokinetic chromatography with laser-induced fluorescence detection.

Science.gov (United States)

Thorsén, G; Bergquist, J

2000-08-18

A method is presented for the chiral analysis of amino acids in biological fluids using micellar electrokinetic chromatography (MEKC) and laser-induced fluorescence (LIF). The amino acids are derivatized with the chiral reagent (+/-)-1-(9-anthryl)-2-propyl chloroformate (APOC) and separated using a mixed micellar separation system. No tedious pre-purification of samples is required. The excellent separation efficiency and good detection capabilities of the MEKC-LIF system are exemplified in the analysis of urine and cerebrospinal fluid. This is the first time MEKC has been reported for chiral analysis of amino acids in biological fluids. The amino acids D-alanine, D-glutamine, and D-aspartic acid have been observed in cerebrospinal fluid, and D-alanine and D-glutamic acid in urine. To the best of our knowledge no measurements of either D-alanine in cerebrospinal fluid or D-glutamic acid in urine have been presented in the literature before.

Automated protein identification by the combination of MALDI MS and MS/MS spectra from different instruments.

Science.gov (United States)

Levander, Fredrik; James, Peter

2005-01-01

The identification of proteins separated on two-dimensional gels is most commonly performed by trypsin digestion and subsequent matrix-assisted laser desorption ionization (MALDI) with time-of-flight (TOF). Recently, atmospheric pressure (AP) MALDI coupled to an ion trap (IT) has emerged as a convenient method to obtain tandem mass spectra (MS/MS) from samples on MALDI target plates. In the present work, we investigated the feasibility of using the two methodologies in line as a standard method for protein identification. In this setup, the high mass accuracy MALDI-TOF spectra are used to calibrate the peptide precursor masses in the lower mass accuracy AP-MALDI-IT MS/MS spectra. Several software tools were developed to automate the analysis process. Two sets of MALDI samples, consisting of 142 and 421 gel spots, respectively, were analyzed in a highly automated manner. In the first set, the protein identification rate increased from 61% for MALDI-TOF only to 85% for MALDI-TOF combined with AP-MALDI-IT. In the second data set the increase in protein identification rate was from 44% to 58%. AP-MALDI-IT MS/MS spectra were in general less effective than the MALDI-TOF spectra for protein identification, but the combination of the two methods clearly enhanced the confidence in protein identification.

Rapid Conformational Analysis of Protein Drugs in Formulation by Hydrogen/Deuterium Exchange Mass Spectrometry (HDX-MS)

DEFF Research Database (Denmark)

Esmail Nazari, Zeinab; van de Weert, Marco; Bou-Assaf, George

2016-01-01

Hydrogen Deuterium Exchange coupled to Mass Spectrometry (HDX-MS) has become an established method for analysis of protein higher-order structure. Here, we use HDX-MS methodology based on manual Solid-Phase Extraction (SPE) to allow fast and simplified conformational analysis of proteins under...... pharmaceutically relevant formulation conditions. Of significant practical utility, the methodology allows global HDX-MS analyses to be performed without refrigeration or external cooling of the setup. In Mode 1, we used DMSO-containing solvents for SPE, allowing the HDX-MS analysis to be performed at acceptable...... in formulation, using an internal HDX reference peptide (P7I) to control for any sample-to-sample variations in back exchange. Advantages of the methodology include low sample use, optimized excipient removal using multiple solvents, and fast data acquisition. Our results indicate that the SPE-HDX-MS system can...

New bioactive silver(I) complexes: Synthesis, characterization, anticancer, antibacterial and anticarbonic anhydrase II activities

Science.gov (United States)

Ozdemir, Ummuhan O.; Ozbek, Neslihan; Genc, Zuhal Karagoz; İlbiz, Firdevs; Gündüzalp, Ayla Balaban

2017-06-01

Silver(I) complexes of alkyl sulfonic acide hydrazides were newly synthesized as homologous series. Methanesulfonic acide hydrazide (L1), ethanesulfonic acide hydrazide (L2), propanesulfonic acide hydrazide (L3) and butanesulfonic acide hydrazide (L4) were used for complexation with Ag(I) ions. The silver complexes obtained in the mol ratio of 1:2 have the structural formula as Ag(L1)2NO3 (I), Ag(L2)2NO3 (II), Ag(L3)2NO3(III), (Ag(L4)2NO3 (IV). The Ag(I) complexes exhibit distorted linear two-fold coordination in [AgL2]+ cations with uncoordinated nitrates. Ligands are chelated with silver(I) ions through unsubstituted primary nitrogen in hydrazide group. Ag(I) complexes were characterized by using elemental analysis, spectroscopic methods (FT-IR, LC-MS), magnetic susceptibility and conductivity measurements. Silver(I) complexes were optimized using PBEPBE/LanL2DZ/DEF2SV basic set performed by DFT method with the Gaussian 09 program package. The geometrical parameters, frontier molecular orbitals (HOMOs and LUMOs) and molecular electrostatic potential (MEP) mapped surfaces of the optimized geometries were also determined by this quantum set. The anticancer activities of silver(I) complexes on MCF-7 human breast cancer cell line were investigated by comparing IC50 values. The antibacterial activities of complexes were studied against Gram positive bacteria; S. aureus ATCC 6538, B. subtilis ATCC 6633, B. cereus NRRL-B-3711, E. faecalis ATCC 29212 and Gram negative bacteria; E. coli ATCC 11230, P. aeruginosa ATCC 15442, K. pneumonia ATCC 70063 by using disc diffusion method. The inhibition activities of Ag(I) complexes on carbonic anhydrase II enzyme (hCA II) were also investigated by comparing IC50 and Ki values. The biological activity screening shows that Ag(I) complex of butanesulfonicacidehydrazide (IV) has the highest activity against tested breast cancer cell lines MCF-7, Gram positive/Gram negative bacteria and carbonic anhydrase II (hCA II) isoenzyme.

HPLC-DAD-MS/MS profiling of antioxidant flavonoid glycosides in sea buckthorn (Hippophae rhamnoides L.) seeds.

Science.gov (United States)

Arimboor, Ranjith; Arumughan, C

2012-09-01

This study was aimed at the chemical profiling of flavonoid glycosides in antioxidant (AO) fractions of sea buckthorn (Hippophae rhamnoides) seed. Seed fractions were evaluated for their DPPH, ABTS, superoxide and hydroxyl radical scavenging, ferric reduction, ferrous chelation and xanthine oxidase inhibitory capacities. HPLC-DAD-ESI-MS/MS analytical conditions for the profiling of seed flavonoids were optimized and the AO-rich fraction was analysed. Quercetin-3-O-rutinoside (5.9%), isorhamnetin-3-O-rutinoside (4.9%) and isorhamnetin-3-O-sophroside-7-O-rhamnoside (3.7%) were found as the major flavonoid glycosides in the fraction. Significant amounts of isorhamnetin-3-O-glucoside (2.8%), 3-O-sophroside-7-O-rhamnosides of quercetin (2.4%) and kaempherol (1.3%), and 3-O-glucoside-7-O-rhamnosides of quercetin (1.1%) and isorhamnetin (1.1%) along with their free forms: isorhamnetin (2.7%), quercetin (1.1%) and kaempherol (0.6%) were also found in the fraction. The identification of flavonoids as the major less polar AO phenolics in the seeds was rationalized by demonstrating the high AO activity of isorhamnetin, quercetin, kaempherol and quercetin-3-O-rutinoside.

High-sensitivity determination of Zn(II) and Cu(II) in vitro by fluorescence polarization

Science.gov (United States)

Thompson, Richard B.; Maliwal, Badri P.; Feliccia, Vincent; Fierke, Carol A.

1998-04-01

Recent work has suggested that free Cu(II) may play a role in syndromes such as Crohn's and Wilson's diseases, as well as being a pollutant toxic at low levels to shellfish and sheep. Similarly, Zn(II) has been implicated in some neural damage in the brain resulting from epilepsy and ischemia. Several high sensitivity methods exist for determining these ions in solution, including GFAAS, ICP-MS, ICP-ES, and electrochemical techniques. However, these techniques are generally slow and costly, require pretreatment of the sample, require complex instruments and skilled personnel, and are incapable of imaging at the cellular and subcellular level. To address these shortcomings we developed fluorescence polarization (anisotropy) biosensing methods for these ions which are very sensitivity, highly selective, require simple instrumentation and little pretreatment, and are inexpensive. Thus free Cu(II) or Zn(II) can be determined at picomolar levels by changes in fluorescence polarization, lifetime, or wavelength ratio using these methods; these techniques may be adapted to microscopy.

Interactions of Hg(ii) with oligonucleotides having thymine-thymine mispairs. Optimization of an impedimetric Hg(ii) sensor.

Science.gov (United States)

Kamal, Ajar; She, Zhe; Sharma, Renu; Kraatz, Heinz-Bernhard

2017-05-21

The present work describes the effect of the number of thymine-thymine mispairs in single strand DNA probes on Hg(ii) interactions and further to develop a highly sensitive DNA based impedimetric sensor for Hg(ii) detection. To achieve this goal, the influence of the number of T-T mispairs on the signal response prompted by DNA-Hg(ii) binding interactions was examined on three designed DNA probes: 5'-OH-(CH 2 ) 6 -S-S-(CH 2 ) 6 -AGTCCACACGTTCCTTACGC-3', 5'-OH-(CH 2 ) 6 -S-S-(CH 2 ) 6 -AGTCCACATTTTCCTTTTGC-3', 5'-OH-(CH 2 ) 6 -S-S-(CH 2 ) 6 -AGTCCATTTTTTCCTTTTTT-3' having 2T-T, 4T-T and 6T-T mispairs with identical length, respectively. This study revealed that the number of T-T mispairs plays a critical role in maximizing the signal intensity of DNA-Hg(ii) binding interactions. Based on these results, DNA comprising maximum number of T-T mispairs was further utilized for construction of the Hg(ii) sensor, which exhibited a linear correlation between the change in charge transfer resistance (ΔR CT ) and the concentration of Hg(ii) over the range of 1.0 × 10 -5 M to 1.0 × 10 -10 M with a lower detection limit of 3.2 × 10 -11 M. The selectivity was tested against 12 different metal ions including Hg(ii). The ΔR CT response from Hg(ii) is 3 times higher than the nearest competitor Pb(ii) and approximately 10 times than other ions. The potential application of such a robust and label-free DNA sensor was demonstrated by analyzing environmental samples collected from Lake Ontario.

Molecular analysis of intact preen waxes of Calidris Canutus (Aves: Scolopacidae) by GC/MS and GC/MS/MS

NARCIS (Netherlands)

Sinninghe Damsté, J.S.; Dekker, M.H.A.; Piersma, T.

2000-01-01

The intact preen wax esters of the red knot Calidris canutus were studied with gas chromatography/mass spectrometry (GC/MS) and GC/MS/MS. In this latter technique, transitions from the molecular ion to fragment ions representing the fatty acid moiety of the wax esters were measured, providing

3400 m/s deuterium pellet injector for Tore Supra

International Nuclear Information System (INIS)

Perin, J.P.; Geraud, A.

1995-01-01

This paper reports on the Tore Supra high velocity pellet injector which was built in Grenoble and after qualification tests installed on Tore Supra Tokomak where it is used for plasma and ablation studies. By using a two stage light gas gun (TSG) and two cells (φ = 3 mm or 4 mm), unsupported pellets pellets (1 to 3.5 10 21 atoms) made directly in the gun by > [1] have been launched into Tore Supra plasma at speeds between 2400m/s and 3400m/s with a reliability of 80%. These higher pellets velocities (> 2500 m/s) [2] are obtained by the optimization of a TSG and the search for the cryogenic conditions of freezing deuterium with good mechanical properties. In particular, the impurities concentration in deuterium during the condensation process has been studied. Several tens pellets have been injected into ohmically and ICR heated plasma and during LH current drive experiments with a good reliability in the range of 3000m/s. These experiments allowed us to extend significantly the ablation data base. Central penetrations can be reached even for high temperatures plasma (3-5 keV) and very peaked density profiles have been obtained in ohmically and ICR heated plasmas A transient improved confinement regime is then observed, which presents some features similar to the PEP regime obtained on JET. (orig.)

Relapsing-Remitting MS (RRMS)

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Full Text Available ... Definition of MS Myelin Immune-Mediated Disease T Cells d What Causes MS? Disproved Theories Viruses Clusters ... d Research News & Progress Research News MSPARIS2017 Stem Cells in MS Progressive MS Research Clinical Trials in ...

Removal of acidic interferences in multi-pesticides residue analysis of fruits using modified magnetic nanoparticles prior to determination via ultra-HPLC-MS/MS

International Nuclear Information System (INIS)

Qi, Peipei; Wang, Zhiwei; Yang, Guiling; Wang, Xinquan; Shang, Chunqing; Xu, Hao; Wang, Xiangyun; Zhang, Hu; Wang, Qiang

2015-01-01

The authors describe magnetite (Fe 3 O 4 ) nanoparticles modified with 3-(N,N-diethylamino) propyltrimethoxysilane (Fe 3 O 4 -PSA NPs) for use as a sorbent for dispersive solid phase extraction of pesticide residues. The Fe 3 O 4 -PSA NPs were prepared by silanizing Fe 3 O 4 NPs and modifying them with 3-(N,N-diethylamino) propyltrimethoxysilane. Field-emission scanning electron microscopy, FTIR and zeta potential measurements were employed to characterize the modified NPs. They were then used as an adsorbent to remove acidic interferences (such as malic acid and succinic acid), which are major interferences in LC-MS/MS analysis in causing ion suppression in the MS spectra of pesticides. In addition, graphitized carbon black (GCB) was used as an adsorbent to eliminate interferences by pigments. The use of Fe 3 O 4 -PSA NPs can replace time-consuming centrifugation as used in the so-called QuEChERS (quick, easy, cheap, effective, rugged and safe) method. This improvement is particularly significant in high-throughput analysis. Following the optimization of the quantities of Fe 3 O 4 -PSA NPs and GCB, the method was applied to the determination of 56 pesticides in (spiked) fruits (apple, kiwi, orange and pear) by ultra-HPLC-MS/MS. The analytical ranges typically extend from 1 to 200 ng∙mL −1 , and recoveries range from 60.2 to 130 % at different concentrations of all four kinds of fruits. The LOQs for the pesticides are 10 ng∙kg −1 , which makes the method a viable tool for pesticide monitoring in fruits. (author)

Development and characterisation of disposable gold electrodes, and their use for lead(II) analysis

Energy Technology Data Exchange (ETDEWEB)

Noh, Mohd F. M. [Cranfield University, Cranfield Health, Silsoe (United Kingdom); Institute for Medical Research, Toxicology and Pharmacology Unit, Herbal Medicine Research Centre, Kuala Lumpur (Malaysia); Tothill, Ibtisam E. [Cranfield University, Cranfield Health, Silsoe (United Kingdom)

2006-12-15

There is an increasing need to assess the harmful effects of heavy-metal-ion pollution on the environment. The ability to detect and measure toxic contaminants on site using simple, cost effective, and field-portable sensors is an important aspect of environmental protection and facilitating rapid decision making. A screen-printed gold sensor in a three-electrode configuration has been developed for analysis of lead(II) by square-wave stripping voltammetry (SWSV). The working electrode was fabricated with gold ink deposited by use of thick-film technology. Conditions affecting the lead stripping response were characterised and optimized. Experimental data indicated that chloride ions are important in lead deposition and subsequent analysis with this type of sensor. A linear concentration range of 10-50 {mu}g L{sup -1} and 25-300 {mu}g L{sup -1} with detection limits of 2 {mu}g L{sup -1} and 5.8 {mu}g L{sup -1} were obtained for lead(II) for measurement times of four and two minutes, respectively. The electrodes can be reused up to 20 times after cleaning with 0.5 mol L{sup -1} sulfuric acid. Interference of other metals with the response to lead were also examined to optimize the sensor response for analysis of environmental samples. The analytical utility of the sensor was demonstrated by applying the system to a variety of wastewater and soil sample extracts from polluted sites. The results are sufficient evidence of the feasibility of using these screen-printed gold electrodes for the determination of lead(II) in wastewater and soil extracts. For comparison purposes a mercury-film electrode and ICP-MS were used for validation. (orig.)

Relapsing-Remitting MS (RRMS)

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Full Text Available ... MS Relapsing-remitting MS (RRMS) Share this page Facebook Twitter Email Relapsing-remitting MS (RRMS) Relapsing-remitting ... Here Start Here Colophon Stay Informed Join Us Facebook Twitter LinkedIn YouTube Pinterest MS Connection About the ...

Relapsing-Remitting MS (RRMS)

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Full Text Available ... d Living Well with MS d Diet, Exercise & Healthy Behaviors Diet & Nutrition Exercise Heat & Temperature Sensitivity Sleep Vaccinations Women's Health Unhealthy Habits Managing MS and Another Condition Aging with MS Anesthesia and Surgery Managing Your MS ...

Relapsing-Remitting MS (RRMS)

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Full Text Available ... to navigation Skip to content Menu Navigation National Multiple Sclerosis Society Sign In In Your Area Donate Donate ... of MS What Causes MS? Who Gets MS? Multiple Sclerosis FAQs Types of MS Related Conditions Symptoms & Diagnosis ...

Relapsing-Remitting MS (RRMS)

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Full Text Available ... Relapsing-remitting MS (RRMS) Share this page Facebook Twitter Email Relapsing-remitting MS (RRMS) Relapsing-remitting MS ( ... Start Here Colophon Stay Informed Join Us Facebook Twitter LinkedIn YouTube Pinterest MS Connection About the Society ...

Search for Bs Oscillations at CDF II

International Nuclear Information System (INIS)

Menzemer, Stephanie

2006-01-01

We report updated results in the search for Bs flavor oscillations performed at CDF II. We analyze a dataset of approximately 355 pb-1 from proton-antiproton collisions at a center-of-mass energy of 1.96 TeV collected in 2002-2004 with the CDF II detector at the Tevatron Collider. Samples of both fully reconstructed Bs → Ds(3)π, and partially reconstructed, Bs → DslX, decays have been studied. A combination of opposite side tagging algorithms has been used to determine the flavor of the Bs mesons at production time. Information about the oscillation frequency of the system, Δms, is obtained by performing an amplitude scan of the data, from which an exclusion limit Δms ≥ 8.6 ps -1 (at 95% C.L.), with a measured sensitivity of 13.0 ps-1 has been derived; Combination with previously available measurements increases the world exclusion limit from 14.5 ps-1 to 16.6 ps-1 (at 95% C.L.)

Study of physicochemical parameters for cadmium (II) and mercury (II) phytoremediation using the specie Eichhornia Crassipes (water hyacinth)

International Nuclear Information System (INIS)

Poma Llantoy, Victor R.; Valderrama Negron, Ana C.

2014-01-01

In this work, the studies were performed to measure the sorption capacity of metal ions Cd (II) and Hg (II) using the specie Eichhornia crassipes (water hyacinth). This study includes assays where the nutrient concentration, the pH and the metal ion concentration were optimized. These tests were carried out at room temperature and with aqueous solutions of Cd (II), Hg (II), in which the samples of Eichhornia crassipes were placed. To confirm the removal of these metals, the waste solutions after the treatment with the Water Hyacinth species were treated using the method APHA 3030-e. However, Eichhornia crassipes samples were treated using the EPA 200.3 method. The concentration of Cd (II) was determined by an ICP-OES spectrometer and Hg (II), by an atomic absorption spectrophotometer. The results showed: Optimal dosage 1 mL of A and 0,5 mL of B, optimum pH 5, optimum concentration of Cd (II) and Hg (II) 5 mg/L for each ion. With these parameters, it was started the removal of 5 mg/L of the metal ions contained in 1 L of solution. Being the percentages of sorption 16,56% for Cd (II) and 15,6% for Hg (II) after a period of 7 days. (author)

Relapsing-Remitting MS (RRMS)

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Full Text Available ... the Challenges of MS You CAN! Webcasts DVDs Books For Kids: Keep S'myelin Información en Español Brochures ... Managing MS and Another Condition Aging with MS Anesthesia and Surgery Managing Your MS d Emotional Well- ...

Relapsing-Remitting MS (RRMS)

Medline Plus

Full Text Available ... the Challenges of MS You CAN! Webcasts DVDs Books For Kids: Keep S'myelin Información en Español Brochures ... MS Managing MS Resources for You and Your Practice Publications for Clinicians Publications for Your Patients MS ...

pDeep: Predicting MS/MS Spectra of Peptides with Deep Learning.

Science.gov (United States)

Zhou, Xie-Xuan; Zeng, Wen-Feng; Chi, Hao; Luo, Chunjie; Liu, Chao; Zhan, Jianfeng; He, Si-Min; Zhang, Zhifei

2017-12-05

In tandem mass spectrometry (MS/MS)-based proteomics, search engines rely on comparison between an experimental MS/MS spectrum and the theoretical spectra of the candidate peptides. Hence, accurate prediction of the theoretical spectra of peptides appears to be particularly important. Here, we present pDeep, a deep neural network-based model for the spectrum prediction of peptides. Using the bidirectional long short-term memory (BiLSTM), pDeep can predict higher-energy collisional dissociation, electron-transfer dissociation, and electron-transfer and higher-energy collision dissociation MS/MS spectra of peptides with >0.9 median Pearson correlation coefficients. Further, we showed that intermediate layer of the neural network could reveal physicochemical properties of amino acids, for example the similarities of fragmentation behaviors between amino acids. We also showed the potential of pDeep to distinguish extremely similar peptides (peptides that contain isobaric amino acids, for example, GG = N, AG = Q, or even I = L), which were very difficult to distinguish using traditional search engines.

Analysis of perfluorinated carboxylic acids in soils II: optimization of chromatography and extraction.

Science.gov (United States)

Washington, John W; Henderson, W Matthew; Ellington, J Jackson; Jenkins, Thomas M; Evans, John J

2008-02-15

With the objective of detecting and quantitating low concentrations of perfluorinated carboxylic acids (PFCAs), including perfluorooctanoic acid (PFOA), in soils, we compared the analytical suitability of liquid chromatography columns containing three different stationary phases, two different liquid chromatography-tandem mass spectrometry (LC/MS/MS) systems, and eight combinations of sample-extract pretreatments, extractions and cleanups on three test soils. For the columns and systems we tested, we achieved the greatest analytical sensitivity for PFCAs using a column with a C(18) stationary phase in a Waters LC/MS/MS. In this system we achieved an instrument detection limit for PFOA of 270 ag/microL, equating to about 14 fg of PFOA on-column. While an elementary acetonitrile/water extraction of soils recovers PFCAs effectively, natural soil organic matter also dissolved in the extracts commonly imparts significant noise that appears as broad, multi-nodal, asymmetric peaks that coelute with several PFCAs. The intensity and elution profile of this noise is highly variable among soils and it challenges detection of low concentrations of PFCAs by decreasing the signal-to-noise contrast. In an effort to decrease this background noise, we investigated several methods of pretreatment, extraction and cleanup, in a variety of combinations, that used alkaline and unbuffered water, acetonitrile, tetrabutylammonium hydrogen sulfate, methyl-tert-butyl ether, dispersed activated carbon and solid-phase extraction. For the combined objectives of complete recovery and minimization of background noise, we have chosen: (1) alkaline pretreatment; (2) extraction with acetonitrile/water; (3) evaporation to dryness; (4) reconstitution with tetrabutylammonium-hydrogen-sulfate ion-pairing solution; (5) ion-pair extraction to methyl-tert-butyl ether; (6) evaporation to dryness; (7) reconstitution with 60/40 acetonitrile/water (v/v); and (8) analysis by LC/MS/MS. Using this method, we

Separation of glycosidic catiomers by TWIM-MS using CO2 as a drift gas.

Science.gov (United States)

Bataglion, Giovana A; Souza, Gustavo Henrique Martins Ferreira; Heerdt, Gabriel; Morgon, Nelson H; Dutra, José Diogo Lisboa; Freire, Ricardo Oliveira; Eberlin, Marcos N; Tata, Alessandra

2015-02-01

Traveling wave ion mobility mass spectrometry (TWIM-MS) is shown to be able to separate and characterize several isomeric forms of diterpene glycosides stevioside (Stv) and rebaudioside A (RebA) that are cationized by Na(+) and K(+) at different sites. Determination and characterization of these coexisting isomeric species, herein termed catiomers, arising from cationization at different and highly competitive coordinating sites, is particularly challenging for glycosides. To achieve this goal, the advantage of using CO2 as a more massive and polarizable drift gas, over N2, was demonstrated. Post-TWIM-MS/MS experiments were used to confirm the separation. Optimization of the possible geometries and cross-sectional calculations for mobility peak assignments were also performed. Copyright © 2015 John Wiley & Sons, Ltd.

Ferro-based derivatizing agents for LC/MS an LC/EC/MS

NARCIS (Netherlands)

Seiwert, Bettina

2007-01-01

Within this thesis, the development and application of ferrocene-based derivatizing agents for LC/MS and LC/EC/MS is presented. The advantages of derivatization by ferrocenes are the similtaneous introduction of a mass tag and an electroactive group, which make them ideally suited for LC/MS and

Determination of Trace Elements in Uranium by HPLC-ID-ICP-MS: NTNFC Final Report

Energy Technology Data Exchange (ETDEWEB)

Manard, Benjamin Thomas [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wylie, Ernest Miller II [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Xu, Ning [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-10-19

This report covers the FY 16 effort for the HPLC-ID-ICP-MS methodology 1) sub-method validation for the group I&II elements, 2) sub-method stood-up and validation for REE, 3) sub-method development for the transition element, and 4) completion of a comprehensive SOP for three families of elements.

Pressurized liquid extracts from Spirulina platensis microalga. Determination of their antioxidant activity and preliminary analysis by micellar electrokinetic chromatography.

Science.gov (United States)

Herrero, Miguel; Ibáñez, Elena; Cifuentes, Alejandro; Señoráns, Javier

2004-08-27

In this work, different extracts from the microalga Spirulina platensis are obtained using pressurized liquid extraction (PLE) and four different solvents (hexane, light petroleum, ethanol and water). Different extraction temperatures (115 and 170 degrees C) were tested using extraction times ranging from 9 to 15 min. The antioxidant activity of the different extracts is determined by means of an in vitro assay using a free radical method. Moreover, a new and fast method is developed using micellar electrokinetic chromatography with diode array detection (MEKC-DAD) to provide a preliminary analysis on the composition of the extracts. This combined application (i.e., in vitro assays plus MEKC-DAD) allowed the fast characterization of the extracts based on their antioxidant activity and the UV-vis spectra of the different compounds found in the extracts. To our knowledge, this work shows for the first time the great possibilities of the combined use of PLE-in vitro assay-MEKC-DAD to investigate natural sources of antioxidants.

Extending the horizons advances in computing, optimization, and decision technologies

CERN Document Server

Joseph, Anito; Mehrotra, Anuj; Trick, Michael

2007-01-01

Computer Science and Operations Research continue to have a synergistic relationship and this book represents the results of cross-fertilization between OR/MS and CS/AI. It is this interface of OR/CS that makes possible advances that could not have been achieved in isolation. Taken collectively, these articles are indicative of the state-of-the-art in the interface between OR/MS and CS/AI and of the high caliber of research being conducted by members of the INFORMS Computing Society. EXTENDING THE HORIZONS: Advances in Computing, Optimization, and Decision Technologies is a volume that presents the latest, leading research in the design and analysis of algorithms, computational optimization, heuristic search and learning, modeling languages, parallel and distributed computing, simulation, computational logic and visualization. This volume also emphasizes a variety of novel applications in the interface of CS, AI, and OR/MS.

NonLinear Parallel OPtimization Tool, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The technological advancement proposed is a novel large-scale Noninear Parallel OPtimization Tool (NLPAROPT). This software package will eliminate the computational...

GC-EI-MS identification data of neutral sugars of polysaccharides extracted from Zizyphus lotus fruit

Directory of Open Access Journals (Sweden)

Khaoula Mkadmini Hammi

2018-06-01

Full Text Available Gas chromatography coupled to mass spectrometer (GC–MS was used to identify and to quantify neutral sugars that constitute the water soluble polysaccharides from Zizyphus lotus fruit. The trimethylsilyl (TMS method was successfully used for derivatization of the monosaccharides units of extracted polysaccharides that were released by hydrolysis method. Sugars were identified based on their retention times compared with those of standards and the NIST MS Spectral Library. All sugars were quantified in TIC (Total Ion Current mode using calibration curves. Data is related to “Optimization extraction of polysaccharide from Tunisian Zizyphus lotus fruit by response surface methodology: Composition and antioxidant activity” (Mkadmini Hammi et al., 2016 [1]. Keywords: Trimethylsilyl, Derivatization, GC–MS, Neutral sugar

Lipid-anthropometric index optimization for insulin sensitivity estimation

Science.gov (United States)

Velásquez, J.; Wong, S.; Encalada, L.; Herrera, H.; Severeyn, E.

2015-12-01

Insulin sensitivity (IS) is the ability of cells to react due to insulińs presence; when this ability is diminished, low insulin sensitivity or insulin resistance (IR) is considered. IR had been related to other metabolic disorders as metabolic syndrome (MS), obesity, dyslipidemia and diabetes. IS can be determined using direct or indirect methods. The indirect methods are less accurate and invasive than direct and they use glucose and insulin values from oral glucose tolerance test (OGTT). The accuracy is established by comparison using spearman rank correlation coefficient between direct and indirect method. This paper aims to propose a lipid-anthropometric index which offers acceptable correlation to insulin sensitivity index for different populations (DB1=MS subjects, DB2=sedentary without MS subjects and DB3=marathoners subjects) without to use OGTT glucose and insulin values. The proposed method is parametrically optimized through a random cross-validation, using the spearman rank correlation as comparator with CAUMO method. CAUMO is an indirect method designed from a simplification of the minimal model intravenous glucose tolerance test direct method (MINMOD-IGTT) and with acceptable correlation (0.89). The results show that the proposed optimized method got a better correlation with CAUMO in all populations compared to non-optimized. On the other hand, it was observed that the optimized method has better correlation with CAUMO in DB2 and DB3 groups than HOMA-IR method, which is the most widely used for diagnosing insulin resistance. The optimized propose method could detect incipient insulin resistance, when classify as insulin resistant subjects that present impaired postprandial insulin and glucose values.

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

Science.gov (United States)

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

2013-01-01

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

Analysis of pesticide residues in strawberries and soils by GC-MS/MS, LC-MS/MS and two-dimensional GC-time-of-flight MS comparing organic and integrated pest management farming.

Science.gov (United States)

Fernandes, Virgínia C; Lehotay, Steven J; Geis-Asteggiante, Lucía; Kwon, Hyeyoung; Mol, Hans G J; van der Kamp, Henk; Mateus, Nuno; Domingues, Valentina F; Delerue-Matos, Cristina

2014-01-01

This study analysed 22 strawberry and soil samples after their collection over the course of 2 years to compare the residue profiles from organic farming with integrated pest management practices in Portugal. For sample preparation, we used the citrate-buffered version of the quick, easy, cheap, effective, rugged, and safe (QuEChERS) method. We applied three different methods for analysis: (1) 27 pesticides were targeted using LC-MS/MS; (2) 143 were targeted using low pressure GC-tandem mass spectrometry (LP-GC-MS/MS); and (3) more than 600 pesticides were screened in a targeted and untargeted approach using comprehensive, two-dimensional gas chromatography time-of-flight mass spectrometry (GC × GC-TOF-MS). Comparison was made of the analyses using the different methods for the shared samples. The results were similar, thereby providing satisfactory confirmation of both similarly positive and negative findings. No pesticides were found in the organic-farmed samples. In samples from integrated pest management practices, nine pesticides were determined and confirmed to be present, ranging from 2 µg kg(-1) for fluazifop-p-butyl to 50 µg kg(-1) for fenpropathrin. Concentrations of residues in strawberries were less than European maximum residue limits.

Quantitative Determination of Perfluorochemicals and Fluorotelomer Alcohols in Plants from Biosolid-Amended Fields using LC/MS/MS and GC/MS

Science.gov (United States)

Analytical methods for determining perfluorochemicals (PFCs) and fluorotelomer alcohols (FTOHs) in plants using liquid chromatography/tandem mass spectrometry (LC/MS/MS) and gas chromatography/mass spectrometry (GC/MS) were developed, and applied to quantify a suite of analytes i...

In Vivo Metabolism Study of Xiamenmycin A in Mouse Plasma by UPLC-QTOF-MS and LC-MS/MS

Directory of Open Access Journals (Sweden)

Feng Lei

2015-01-01

Full Text Available Xiamenmycin A is an antifibrotic leading compound with a benzopyran skeleton that is isolated from mangrove-derived Streptomyces xiamenensis. As a promising small molecule for fibrotic diseases, less information is known about its metabolic characteristics in vivo. In this study, the time-course of xiamenmycin A in mouse plasma was investigated by relative quantification. After two types of administration of xiamenmycin A at a single dose of 10 mg/kg, the plasma concentrations were measured quantitatively by LC-MS/MS. The dynamic changes in the xiamenmycin A concentration showed rapid absorption and quick elimination in plasma post-administration. Four metabolites (M1–M4 were identified in blood by UPLC-QTOF-MS, and xiamenmycin B (M3 is the principal metabolite in vivo, as verified by comparison of the authentic standard sample. The structures of other metabolites were identified based on the characteristics of their MS and MS/MS data. The newly identified metabolites are useful for understanding the metabolism of xiamenmycin A in vivo, aiming at the development of an anti-fibrotic drug candidate for the therapeutic treatment of excessive fibrotic diseases.

Relapsing-Remitting MS (RRMS)

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Full Text Available ... Become an MS Activist Take Action Current Advocacy Issues Advocacy Results Advocacy News d Raise Awareness d ... MS are more likely to experience gradually worsening problems with walking and mobility, along with whatever other symptoms they may have. Diagnosing relapsing-remitting MS (RRMS) Learn More Learn More ... Room MS Prevalence ...

Wellness and multiple sclerosis: The National MS Society establishes a Wellness Research Working Group and research priorities.

Science.gov (United States)

Motl, Robert W; Mowry, Ellen M; Ehde, Dawn M; LaRocca, Nicholas G; Smith, Kathy E; Costello, Kathleen; Shinto, Lynne; Ng, Alexander V; Sullivan, Amy B; Giesser, Barbara; McCully, Kevin K; Fernhall, Bo; Bishop, Malachy; Plow, Matthew; Casaccia, Patrizia; Chiaravalloti, Nancy D

2018-03-01

People with multiple sclerosis (MS) have identified "wellness" and associated behaviors as a high priority based on "social media listening" undertaken by the National MS Society (i.e. the Society). The Society recently convened a group that consisted of researchers with experience in MS and wellness-related research, Society staff members, and an individual with MS for developing recommendations regarding a wellness research agenda. The members of the group engaged in focal reviews and discussions involving the state of science within three approaches for promoting wellness in MS, namely diet, exercise, and emotional wellness. That process informed a group-mediated activity for developing and prioritizing research goals for wellness in MS. This served as a background for articulating the mission and objectives of the Society's Wellness Research Working Group. The primary mission of the Wellness Research Working Group is the provision of scientific evidence supporting the application of lifestyle, behavioral, and psychosocial approaches for promoting optimal health of mind, body, and spirit (i.e. wellness) in people with MS as well as managing the disease and its consequences.

Survey of diagnostic and treatment practices for multiple sclerosis (MS) in Europe. Part 2: Progressive MS, paediatric MS, pregnancy and general management.

Science.gov (United States)

Fernández, O; Delvecchio, M; Edan, G; Fredrikson, S; Giovannoni, G; Hartung, H-P; Havrdova, E; Kappos, L; Pozzilli, C; Soerensen, P S; Tackenberg, B; Vermersch, P; Comi, G

2018-05-01

The European Charcot Foundation supported the development of a set of surveys to understand current practice patterns for the diagnosis and management of multiple sclerosis (MS) in Europe. Part 2 of the report summarizes survey results related to secondary progressive MS (SPMS), primary progressive MS (PPMS), pregnancy, paediatric MS and overall patient management. A steering committee of MS neurologists developed case- and practice-based questions for two sequential surveys distributed to MS neurologists throughout Europe. Respondents generally favoured changing rather than stopping disease-modifying treatment (DMT) in patients transitioning from relapsing-remitting MS to SPMS, particularly with active disease. Respondents would not initiate DMT in patients with typical PPMS symptoms, although the presence of ≥1 spinal cord or brain gadolinium-enhancing lesion might affect that decision. For patients considering pregnancy, respondents were equally divided on whether to stop treatment before or after conception. Respondents strongly favoured starting DMT in paediatric MS with active disease; recommended treatments included interferon, glatiramer acetate and, in John Cunningham virus negative patients, natalizumab. Additional results regarding practice-based questions and management are summarized. Results of part 2 of the survey of diagnostic and treatment practices for MS in Europe largely mirror results for part 1, with neurologists in general agreement about the treatment and management of SPMS, PPMS, pregnancy and paediatric MS as well as the general management of MS. However, there are also many areas of disagreement, indicating the need for evidence-based recommendations and/or guidelines. © 2018 EAN.

Optimizing the magnetization-prepared rapid gradient-echo (MP-RAGE sequence.

Directory of Open Access Journals (Sweden)

Jinghua Wang

Full Text Available The three-dimension (3D magnetization-prepared rapid gradient-echo (MP-RAGE sequence is one of the most popular sequences for structural brain imaging in clinical and research settings. The sequence captures high tissue contrast and provides high spatial resolution with whole brain coverage in a short scan time. In this paper, we first computed the optimal k-space sampling by optimizing the contrast of simulated images acquired with the MP-RAGE sequence at 3.0 Tesla using computer simulations. Because the software of our scanner has only limited settings for k-space sampling, we then determined the optimal k-space sampling for settings that can be realized on our scanner. Subsequently we optimized several major imaging parameters to maximize normal brain tissue contrasts under the optimal k-space sampling. The optimal parameters are flip angle of 12°, effective inversion time within 900 to 1100 ms, and delay time of 0 ms. In vivo experiments showed that the quality of images acquired with our optimal protocol was significantly higher than that of images obtained using recommended protocols in prior publications. The optimization of k-spacing sampling and imaging parameters significantly improved the quality and detection sensitivity of brain images acquired with MP-RAGE.

Sulphur fertilization influences the sulphur species composition in Allium sativum: sulphomics using HPLC-ICPMS/MS-ESI-MS/MS.

Science.gov (United States)

Raab, Andrea; Ronzan, Marilena; Feldmann, Joerg

2017-10-18

Garlic (A. sativum) contains a large number of small sulphur (S)-containing metabolites, which are important for its taste and smell and vary with A. sativum variety and growth conditions. This study was designed to investigate the influence of different sulphur-fertilization regimes on low molecular weight S-species by attempting the first sulphur mass balance in A. sativum roots and bulbs using HPLC-ICPMS/MS-ESI-MS/MS. Species unspecific quantification of acid soluble S-containing metabolites was achieved using HPLC-ICP-MS/MS. For identification of the compounds, high resolution ESI-MS (Orbitrap LTQ and q-TOF) was used. The plants contained up to 54 separated sulphur-containing compounds, which constitute about 80% of the total sulphur present in A. sativum. The roots and bulbs of A. sativum contained the same compounds, but not necessarily the same amounts and proportions. The S-containing metabolites in the roots reacted more sensitively to manipulations of sulphur fertilization than those compounds in the bulbs. In addition to known compounds (e.g. γ-glutamyl-S-1-propenylcysteine) we were able to identify and partially quantify 31 compounds. Three as yet undescribed S-containing compounds were also identified and quantified for the first time. Putative structures were assigned to the oxidised forms of S-1-propenylmercaptoglutathione, S-2-propenylmercaptoglutathione, S-allyl/propenyl-containing PC-2 and 2-amino-3-[(2-carboxypropyl)sulfanyl]propanoic acid. The parallel use of ICP-MS/MS as a sulphur-specific detector and ESI-MS as a molecular detector simplifies the identification and quantification of sulphur containing metabolites without species specific standards. This non-target analysis approach enables a mass balance approach and identifies the occurrence of the so far unidentified organosulphur compounds. The experiments showed that the sulphur-fertilization regime does not influence sulphur-speciation, but the concentration of some S

Rotorcraft Optimization Tools: Incorporating Rotorcraft Design Codes into Multi-Disciplinary Design, Analysis, and Optimization

Science.gov (United States)

Meyn, Larry A.

2018-01-01

One of the goals of NASA's Revolutionary Vertical Lift Technology Project (RVLT) is to provide validated tools for multidisciplinary design, analysis and optimization (MDAO) of vertical lift vehicles. As part of this effort, the software package, RotorCraft Optimization Tools (RCOTOOLS), is being developed to facilitate incorporating key rotorcraft conceptual design codes into optimizations using the OpenMDAO multi-disciplinary optimization framework written in Python. RCOTOOLS, also written in Python, currently supports the incorporation of the NASA Design and Analysis of RotorCraft (NDARC) vehicle sizing tool and the Comprehensive Analytical Model of Rotorcraft Aerodynamics and Dynamics II (CAMRAD II) analysis tool into OpenMDAO-driven optimizations. Both of these tools use detailed, file-based inputs and outputs, so RCOTOOLS provides software wrappers to update input files with new design variable values, execute these codes and then extract specific response variable values from the file outputs. These wrappers are designed to be flexible and easy to use. RCOTOOLS also provides several utilities to aid in optimization model development, including Graphical User Interface (GUI) tools for browsing input and output files in order to identify text strings that are used to identify specific variables as optimization input and response variables. This paper provides an overview of RCOTOOLS and its use

Optimal trajectory generation for mechanical arms. M.S. Thesis

Science.gov (United States)

Iemenschot, J. A.

1972-01-01

A general method of generating optimal trajectories between an initial and a final position of an n degree of freedom manipulator arm with nonlinear equations of motion is proposed. The method is based on the assumption that the time history of each of the coordinates can be expanded in a series of simple time functions. By searching over the coefficients of the terms in the expansion, trajectories which minimize the value of a given cost function can be obtained. The method has been applied to a planar three degree of freedom arm.

Urinary metabolite profiling of flavonoids in Chinese volunteers after consumption of orange juice by UFLC-Q-TOF-MS/MS.

Science.gov (United States)

Zeng, Xuan; Su, Weiwei; Bai, Yang; Chen, Taobin; Yan, Zenghao; Wang, Jiawei; Su, Minmin; Zheng, Yuying; Peng, Wei; Yao, Hongliang

2017-09-01

The metabolism of flavonoids derived from orange juice in Chinese volunteers has not been well investigated. With the ultra-fast liquid chromatography-quadrupole-time-of-flight tandem mass spectrometry (UFLC-Q-TOF-MS/MS) system, orange juice-derived flavonoids, as well as metabolites contained in urine collected from healthy Chinese volunteers after consumption of 250mL orange juice, were systematically identified and quantified. Finally, a total of 9 flavonoids and 30 metabolites were detected. Obtained results revealed that flavonoids derived from orange juice underwent extensive phase II metabolism in human, mainly comprising glucuronidation and sulfation. The overall recovery of the primary flavonoid aglycones, i.e., naringenin and hesperetin, were both approximately equivalent 22% of intake, primarily occurred in 4-12h post consumption. Meanwhile, additional 35 phenolic catabolites were identified in urine collected post consumption. However, it is difficult to determine the exact amounts of phenolic catabolites derived from specific flavonoid due to the interference of diets and other flavonoids. This work would be valuable for the clarification of metabolic profiles for flavonoids in Chinese population. Copyright © 2017 Elsevier B.V. All rights reserved.

Proanthocyanidin screening by LC-ESI-MS of Portuguese red wines made with teinturier grapes.

Science.gov (United States)

Teixeira, Natércia; Azevedo, Joana; Mateus, Nuno; de Freitas, Victor

2016-01-01

Proanthocyanidins (PAs) are one of the most important polyphenolic compounds in wine. Among PAs, prodelphinidin (PD) dimers and trimers have not been widely detected in wines due to the lack of available commercial standards and the difficulty to detect and isolate them from natural sources. LC-ESI-MS (liquid chromatography-electrospray ionization-mass spectrometry) with the right chromatographic conditions has proven to be a powerful tool for PAs detection and identification in complex samples. This technique has been applied to an exhaustive study of PA composition of two Portuguese red wines made with teinturier grapes, especially for the identification of PD dimers and trimers. Tandem mass spectrometry (MS/MS) with ion trap provided additional information about the structures of these compounds through the fragmentation patterns of the pseudomolecular ions. A LC-ESI-MS method was optimized and 41 different compounds were found. Among them are included 8 PD dimers and 13 PD trimers. Copyright © 2015 Elsevier Ltd. All rights reserved.

Rapid determination of piracetam in human plasma and cerebrospinal fluid by micellar electrokinetic chromatography with sample direct injection.

Science.gov (United States)

Yeh, Hsin-Hua; Yang, Yuan-Han; Ko, Ju-Yun; Chen, Su-Hwei

2006-07-07

A simple micellar electrokinetic chromatography (MEKC) method with UV detection at 200 nm for analysis of piracetam in plasma and in cerebrospinal fluid (CSF) by direct injection without any sample pretreatment is described. The separation of piracetam from biological matrix was performed at 25 degrees C using a background electrolyte consisting of Tris buffer with sodium dodecyl sulfate (SDS) as the electrolyte solution. Several parameters affecting the separation of the drug from biological matrix were studied, including the pH and concentrations of the Tris buffer and SDS. Under optimal MEKC condition, good separation with high efficiency and short analyses time is achieved. Using imidazole as an internal standard (IS), the linear ranges of the method for the determination of piracetam in plasma and in CSF were all between 5 and 500 microg/mL; the detection limit of the drug in plasma and in CSF (signal-to-noise ratio=3; injection 0.5 psi, 5s) was 1.0 microg/mL. The applicability of the proposed method for determination of piracetam in plasma and CSF collected after intravenous administration of 3g piracetam every 6h and oral administration 1.2g every 6h in encephalopathy patients with aphasia was demonstrated.

Characterization, stoichiometry, and stability of salivary protein-tannin complexes by ESI-MS and ESI-MS/MS.

Science.gov (United States)

Canon, Francis; Paté, Franck; Meudec, Emmanuelle; Marlin, Thérèse; Cheynier, Véronique; Giuliani, Alexandre; Sarni-Manchado, Pascale

2009-12-01

Numerous protein-polyphenol interactions occur in biological and food domains particularly involving proline-rich proteins, which are representative of the intrinsically unstructured protein group (IUP). Noncovalent protein-ligand complexes are readily detected by electrospray ionization mass spectrometry (ESI-MS), which also gives access to ligand binding stoichiometry. Surprisingly, the study of interactions between polyphenolic molecules and proteins is still an area where ESI-MS has poorly benefited, whereas it has been extensively applied to the detection of noncovalent complexes. Electrospray ionization mass spectrometry has been applied to the detection and the characterization of the complexes formed between tannins and a human salivary proline-rich protein (PRP), namely IB5. The study of the complex stability was achieved by low-energy collision-induced dissociation (CID) measurements, which are commonly implemented using triple quadrupole, hybrid quadrupole time-of-flight, or ion trap instruments. Complexes composed of IB5 bound to a model polyphenol EgCG have been detected by ESI-MS and further analyzed by MS/MS. Mild ESI interface conditions allowed us to observe intact noncovalent PRP-tannin complexes with stoichiometries ranging from 1:1 to 1:5. Thus, ESI-MS shows its efficiency for (1) the study of PRP-tannin interactions, (2) the determination of stoichiometry, and (3) the study of complex stability. We were able to establish unambiguously both their stoichiometries and their overall subunit architecture via tandem mass spectrometry and solution disruption experiments. Our results prove that IB5.EgCG complexes are maintained intact in the gas phase.

Optimal synthesis of a Ni(II)-dimethylglyoxime ion-imprinted polymer ...

African Journals Online (AJOL)

A Ni(II)-dimethylglyoxime ion-imprinted polymer {Ni(II)-DMG IIP} was optimised by the uniform design experimental ... The bonds formed between the template and the functional monomers in ion- imprinted polymerisation reactions are weaker, non-covalent. (Arshady and Mosbach, 1981; ..... where the polymer did not form.

Ship Pipe Routing Design Using NSGA-II and Coevolutionary Algorithm

Directory of Open Access Journals (Sweden)

Wentie Niu

2016-01-01

Full Text Available Pipe route design plays a prominent role in ship design. Due to the complex configuration in layout space with numerous pipelines, diverse design constraints, and obstacles, it is a complicated and time-consuming process to obtain the optimal route of ship pipes. In this article, an optimized design method for branch pipe routing is proposed to improve design efficiency and to reduce human errors. By simplifying equipment and ship hull models and dividing workspace into three-dimensional grid cells, the mathematic model of layout space is constructed. Based on the proposed concept of pipe grading method, the optimization model of pipe routing is established. Then an optimization procedure is presented to deal with pipe route planning problem by combining maze algorithm (MA, nondominated sorting genetic algorithm II (NSGA-II, and cooperative coevolutionary nondominated sorting genetic algorithm II (CCNSGA-II. To improve the performance in genetic algorithm procedure, a fixed-length encoding method is presented based on improved maze algorithm and adaptive region strategy. Fuzzy set theory is employed to extract the best compromise pipeline from Pareto optimal solutions. Simulation test of branch pipe and design optimization of a fuel piping system were carried out to illustrate the design optimization procedure in detail and to verify the feasibility and effectiveness of the proposed methodology.

Determination of reduced homocysteine in human serum by elemental labelling and liquid chromatography with ICP-MS and ESI-MS detection.

Science.gov (United States)

Espina, Juan Gómez; Montes-Bayón, Maria; Blanco-González, Elisa; Sanz-Medel, Alfredo

2015-10-01

Analytical methods allowing sensitive determination of reduced homocysteine (rHcy), one of the so-called biothiols, in human serum is a topic of growing interest due to its close relation to several human disorders, mainly cardiovascular diseases. Although most widely used analytical strategies to determine total Hcy involve derivatization by means of fluorescent labels, this work proposes the use of ebselen, a Se-containing labelling agent to derivatize the reactive sulfhydryl group of the Hcy molecule in its "free" reduced form, which is more likely to play different roles in disease pathogenesis. Optimization of the derivatization and separation conditions by high-performance liquid chromatography (HPLC) to isolate the excess of derivatizing reagent is carried out here using UV/VIS detection. Further, the study of the Se labelling reaction by electrospray ionization tandem mass spectrometry (ESI-MS/MS) provides a stoichiometry of the derivative of 1:1. The main advantage of using ebselen as a labelling agent is the presence of the Se atom in the molecule that allows the use of inductively coupled plasma mass spectrometry (ICP-MS) as a sensitive and selective Se detector. The coupling of HPLC with ICP-MS provided excellent features for the determination of Se-derivatized rHcy (detection limit of 9.6 nM) in real samples. Quantification was accomplished by using post-column isotope dilution (ID) of Se in serum samples, after precipitation of the main serum proteins. Quantitative results for "free" rHcy turned out to be around 0.18-0.22 μM in serum samples from healthy individuals that could be directly analyzed without sample preconcentration.

An improved method of sample preparation on AnchorChip targets for MALDI-MS and MS/MS and its application in the liver proteome project

DEFF Research Database (Denmark)

Zhang, Xumin; Shi, Liang; Shu, Shaokung

2007-01-01

An improved method for sample preparation for MALDI-MS and MS/MS using AnchorChip targets is presented. The method, termed the SMW method (sample, matrix wash), results in better sensitivity for peptide mass fingerprinting as well as for sequencing by MS/MS than previously published methods. The ...

Optimization in the nuclear fuel cycle II: Surface contamination

International Nuclear Information System (INIS)

Pereira, W.S.; Silva, A.X.; Lopes, J.M.; Carmo, A.S.; Fernandes, T.S.; Mello, C.R.; Kelecom, A.

2017-01-01

Optimization is one of the bases of radioprotection and aims to move doses away from the dose limit that is the borderline of acceptable radiological risk. This work aims to use the monitoring of surface contamination as a tool of the optimization process. 53 surface contamination points were analyzed at a nuclear fuel cycle facility. Three sampling points were identified with monthly mean values of contamination higher than 1 Bq ∙ cm -2 , points 28, 42 and 47. These points were indicated for the beginning of the optimization process

Ultrasonic-assisted extraction combined with sample preparation and analysis using LC-ESI-MS/MS allowed the identification of 24 new phenolic compounds in pecan nut shell [Carya illinoinensis (Wangenh) C. Koch] extracts.

Science.gov (United States)

Hilbig, Josiane; Alves, Victor Rodrigues; Müller, Carmen Maria Olivera; Micke, Gustavo Amadeu; Vitali, Luciano; Pedrosa, Rozangela Curi; Block, Jane Mara

2018-04-01

Ultrasonic-assisted extraction combined with statistical tools (factorial design, response surface methodology and kinetics) were used to evaluate the effects of the experimental conditions of temperature, solid-to-solvent ratio, ethanol concentration and time for the extraction of the total phenolic content from pecan nut shells. The optimal conditions for the aqueous and hydroalcoholic extract (with 20% v/v of ethanol) were 60 and 80 °C; solid to solvent ratio of 30 mL·g -1 (for both) and extraction time of 35 and 25 min, respectively. Using these optimize extraction conditions, 426 and 582 mg GAE·g -1 of phenolic compounds, from the aqueous and hydroalcoholic phases respectively, were obtained. In addition, the analysis of the phenolic compounds using the LC-ESI-MS/MS system allowed the identification of 29 phenolic compounds, 24 of which had not been reported in literature for this raw material yet. Copyright © 2018. Published by Elsevier Ltd.

Relapsing-Remitting MS (RRMS)

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An in silico MS/MS library for automatic annotation of novel FAHFA lipids.

Science.gov (United States)

Ma, Yan; Kind, Tobias; Vaniya, Arpana; Gennity, Ingrid; Fahrmann, Johannes F; Fiehn, Oliver

2015-01-01

A new lipid class named 'fatty acid esters of hydroxyl fatty acids' (FAHFA) was recently discovered in mammalian adipose tissue and in blood plasma and some FAHFAs were found to be associated with type 2 diabetes. To facilitate the automatic annotation of FAHFAs in biological specimens, a tandem mass spectra (MS/MS) library is needed. Due to the limitation of the commercial available standard compounds, we proposed building an in silico MS/MS library to extend the coverage of molecules. We developed a computer-generated library with 3267 tandem mass spectra (MS/MS) for 1089 FAHFA species. FAHFA spectra were generated based on authentic standards with negative mode electrospray ionization and 10, 20, and 40 V collision induced dissociation at 4 spectra/s as used in in ultra-high performance liquid chromatography-QTOF mass spectrometry studies. However, positional information of the hydroxyl group is only obtained either at lower QTOF spectra acquisition rates of 1 spectrum/s or at the MS(3) level in ion trap instruments. Therefore, an additional set of 4290 fragment-rich MS/MS spectra was created to enable distinguishing positional FAHFA isomers. The library was generated based on ion fragmentations and ion intensities of FAHFA external reference standards, developing a heuristic model for fragmentation rules and extending these rules to large swaths of computer-generated structures of FAHFAs with varying chain lengths, degrees of unsaturation and hydroxyl group positions. Subsequently, we validated the new in silico library by discovering several new FAHFA species in egg yolk, showing that this library enables high-throughput screening of FAHFA lipids in various biological matrices. The developed library and templates are freely available for commercial or noncommercial use at http://fiehnlab.ucdavis.edu/staff/yanma/fahfa-lipid-library. This in silico MS/MS library allows users to annotate FAHFAs from accurate mass tandem mass spectra in an easy and fast manner

Structure Elucidation of Unknown Metabolites in Metabolomics by Combined NMR and MS/MS Prediction.

Science.gov (United States)

Boiteau, Rene M; Hoyt, David W; Nicora, Carrie D; Kinmonth-Schultz, Hannah A; Ward, Joy K; Bingol, Kerem

2018-01-17

We introduce a cheminformatics approach that combines highly selective and orthogonal structure elucidation parameters; accurate mass, MS/MS (MS²), and NMR into a single analysis platform to accurately identify unknown metabolites in untargeted studies. The approach starts with an unknown LC-MS feature, and then combines the experimental MS/MS and NMR information of the unknown to effectively filter out the false positive candidate structures based on their predicted MS/MS and NMR spectra. We demonstrate the approach on a model mixture, and then we identify an uncatalogued secondary metabolite in Arabidopsis thaliana . The NMR/MS² approach is well suited to the discovery of new metabolites in plant extracts, microbes, soils, dissolved organic matter, food extracts, biofuels, and biomedical samples, facilitating the identification of metabolites that are not present in experimental NMR and MS metabolomics databases.

Analytical Method Details (MS): SE53_MS03 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available SE53_MS03 CE-TOF/MS Agilent CE capillary electrophoresis system,Agilent G3250AA LC/...s were performed using an Agilent CE capillary electrophoresis system (Agilent Technologies, Waldbronn, Germ

Quality evaluation of LC-MS/MS-based E. coli H antigen typing (MS-H) through label-free quantitative data analysis in a clinical sample setup.

Science.gov (United States)

Cheng, Keding; Sloan, Angela; McCorrister, Stuart; Peterson, Lorea; Chui, Huixia; Drebot, Mike; Nadon, Celine; Knox, J David; Wang, Gehua

2014-12-01

The need for rapid and accurate H typing is evident during Escherichia coli outbreak situations. This study explores the transition of MS-H, a method originally developed for rapid H antigen typing of E. coli using LC-MS/MS of flagella digest of reference strains and some clinical strains, to E. coli isolates in clinical scenario through quantitative analysis and method validation. Motile and nonmotile strains were examined in batches to simulate clinical sample scenario. Various LC-MS/MS batch run procedures and MS-H typing rules were compared and summarized through quantitative analysis of MS-H data output for a standard method development. Label-free quantitative data analysis of MS-H typing was proven very useful for examining the quality of MS-H result and the effects of some sample carryovers from motile E. coli isolates. Based on this, a refined procedure and protein identification rule specific for clinical MS-H typing was established and validated. With LC-MS/MS batch run procedure and database search parameter unique for E. coli MS-H typing, the standard procedure maintained high accuracy and specificity in clinical situations, and its potential to be used in a clinical setting was clearly established. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Brief International Cognitive Assessment for MS (BICAMS): international standards for validation.

Science.gov (United States)

Benedict, Ralph H B; Amato, Maria Pia; Boringa, Jan; Brochet, Bruno; Foley, Fred; Fredrikson, Stan; Hamalainen, Paivi; Hartung, Hans; Krupp, Lauren; Penner, Iris; Reder, Anthony T; Langdon, Dawn

2012-07-16

An international expert consensus committee recently recommended a brief battery of tests for cognitive evaluation in multiple sclerosis. The Brief International Cognitive Assessment for MS (BICAMS) battery includes tests of mental processing speed and memory. Recognizing that resources for validation will vary internationally, the committee identified validation priorities, to facilitate international acceptance of BICAMS. Practical matters pertaining to implementation across different languages and countries were discussed. Five steps to achieve optimal psychometric validation were proposed. In Step 1, test stimuli should be standardized for the target culture or language under consideration. In Step 2, examiner instructions must be standardized and translated, including all information from manuals necessary for administration and interpretation. In Step 3, samples of at least 65 healthy persons should be studied for normalization, matched to patients on demographics such as age, gender and education. The objective of Step 4 is test-retest reliability, which can be investigated in a small sample of MS and/or healthy volunteers over 1-3 weeks. Finally, in Step 5, criterion validity should be established by comparing MS and healthy controls. At this time, preliminary studies are underway in a number of countries as we move forward with this international assessment tool for cognition in MS.

Multi-Segment Direct Inject nano-ESI-LTQ-FT-ICR-MS/MS For Protein Identification

Directory of Open Access Journals (Sweden)

Neal Rachel E

2011-07-01

Full Text Available Abstract Reversed phase high performance liquid chromatography (HPLC interfaced to electrospray tandem mass spectrometry (MS/MS is commonly used for the identification of peptides from proteolytically cleaved proteins embedded in a polyacrylamide gel matrix as well as for metabolomics screening. HPLC separations are time consuming (30-60 min average, costly (columns and mobile phase reagents, and carry the risk of column carry over between samples. The use of a chip-based nano-ESI platform (Advion NanoMate based on replaceable nano-tips for sample introduction eliminates sample cross-contamination, provides unchanging sample matrix, and enhances spray stability with attendant increases in reproducibility. Recent papers have established direct infusion nano-ESI-MS/MS utilizing the NanoMate for protein identification of gel spots based on full range MS scans with data dependent MS/MS. In a full range scan, discontinuous ion suppression due to sample matrix can impair identification of putative mass features of interest in both the proteomic and metabolomic workflows. In the current study, an extension of an established direct inject nano-ESI-MS/MS method is described that utilizes the mass filtering capability of an ion-trap for ion packet separation into four narrow mass ranges (50 amu overlap with segment specific dynamic data dependent peak inclusion for MS/MS fragmentation (total acquisition time of 3 minutes. Comparison of this method with a more traditional nanoLC-MS/MS based protocol utilizing solvent/sample stream splitting to achieve nanoflow demonstrated comparable results for protein identification from polyacrylamide gel matrices. The advantages of this method include full automation, lack of cross-contamination, low cost, and high throughput.

Lead isotope ratio analysis of bullet samples by using quadrupole ICP-MS

International Nuclear Information System (INIS)

Tamura, Shu-ichi; Hokura, Akiko; Nakai, Izumi; Oishi, Masahiro

2006-01-01

The measurement conditions for the precise analysis of the lead stable isotope ratio by using an ICP-MS equipped with a quadrupole mass spectrometer were studied in order to apply the technique to the forensic identification of bullet samples. The values of the relative standard deviation obtained for the ratio of 208 Pb/ 206 Pb, 207 Pb/ 206 Pb and 204 Pb/ 206 Pb were lower than 0.2% after optimization of the analytical conditions, including the optimum lead concentration of the sample solution to be about 70 ppb and an integration time for 1 m/s of 15 s. This method was applied to an analysis of lead in bullets for rifles and handguns; a stable isotope ratio of lead was found to be suitable for the identification of bullets. This study has demonstrated that the lead isotope ratio measured by using a quadrupole ICP-MS was useful for a practical analysis of bullet samples in forensic science. (author)

Quantitative analysis of 39 polybrominated diphenyl ethers by isotope dilution GC/low-resolution MS.

Science.gov (United States)

Ackerman, Luke K; Wilson, Glenn R; Simonich, Staci L

2005-04-01

A GC/low-resolution MS method for the quantitative isotope dilution analysis of 39 mono- to heptabrominated diphenyl ethers was developed. The effects of two different ionization sources, electron impact (EI) and electron capture negative ionization (ECNI), and the effects of their parameters on production of high-mass fragment ions [M - xH - yBr](-) specific to PBDEs were investigated. Electron energy, emission current, source temperature, ECNI system pressure, and choice of ECNI reagent gases were optimized. Previously unidentified enhancement of PBDE high-mass fragment ion [M - xH - yBr](-) abundance was achieved. Electron energy had the largest impact on PBDE high-mass fragment ion abundance for both the ECNI and EI sources. By monitoring high-mass fragment ions of PBDEs under optimized ECNI source conditions, quantitative isotope dilution analysis of 39 PBDEs was conducted using nine (13)C(12) labeled PBDEs on a low-resolution MS with low picogram to femtogram instrument detection limits.

Relapsing-Remitting MS (RRMS)

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Relapsing-Remitting MS (RRMS)

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Relapsing-Remitting MS (RRMS)

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Full Text Available ... Disease T Cells d What Causes MS? Disproved Theories Viruses Clusters d Who Gets MS? Pediatric MS ... of Distinction Lawry Circle Circle of Influence d Planned Giving d Other Ways to Give Donate by ...

Relapsing-Remitting MS (RRMS)

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Relapsing-Remitting MS (RRMS)

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Relapsing-Remitting MS (RRMS)

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Relapsing-Remitting MS (RRMS)

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Full Text Available ... working effectively. How does RRMS differ from progressive types of MS? While RRMS is defined by attacks ... Pinterest MS Connection About the Society Vision Careers Leadership Cultural Values Financials News Press Room MS Prevalence ...

Relapsing-Remitting MS (RRMS)

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Simultaneous quantification of endogenous and exogenous plasma glucose by isotope dilution LC-MS/MS with indirect MRM of the derivative tag.

Science.gov (United States)

Yu, Lingling; Wen, Chao; Li, Xing; Fang, Shiqi; Yang, Lichuan; Wang, Tony; Hu, Kaifeng

2018-03-01

Quantification of endogenous and exogenous plasma glucose can help more comprehensively evaluate the glucose metabolic status. A ratio-based approach using isotope dilution liquid chromatography tandem mass spectrometry (ID LC-MS/MS) with indirect multiple reaction monitoring (MRM) of the derivative tag was developed to simultaneously quantify endo-/exogenous plasma glucose. Using diluted D-[ 13 C 6 ] glucose as tracer of exogenous glucose, 12 C 6 / 13 C 6 glucoses were first derivatized and then data were acquired in MRM mode. The metabolism of exogenous glucose can be tracked and the concentration ratio of endo/exo-genous glucose can be measured by calculating the endo-/exo-genous glucose concentrations from peak area ratio of specific daughter ions. Joint application of selective derivatization and MRM analysis not only improves the sensitivity but also minimizes the interference from the background of plasma, which warrants the accuracy and reproducibility. Good agreement between the theoretical and calculated concentration ratios was obtained with a linear correlation coefficient (R) of 0.9969 in the range of D-glucose from 0.5 to 20.0 mM, which covers the healthy and diabetic physiological scenarios. Satisfactory reproducibility was obtained by evaluation of the intra- and inter-day precisions with relative standard deviations (RSDs) less than 5.16%, and relative recoveries of 85.96 to 95.92% were obtained at low, medium, and high concentration, respectively. The method was successfully applied to simultaneous determination of the endo-/exogenous glucose concentration in plasma of non-diabetic and type II diabetic cynomolgus monkeys. Graphical Abstract The scheme of the proposed ratio-based approach using isotope dilution LC-MS/MS with indirect MRM of the derivative tag for simultaneous quantification of endogenous and exogenous plasma glucose.

Simultaneous analysis of 17 diuretics in dietary supplements by HPLC and LC-MS/MS.

Science.gov (United States)

Woo, H; Kim, J W; Han, K M; Lee, J H; Hwang, I S; Lee, J H; Kim, J; Kweon, S J; Cho, S; Chae, K R; Han, S Y; Kim, J

2013-01-01

In order to test health foods for illegally added diuretics for weight loss, we developed simple, rapid, selective, and sensitive methods using HPLC and LC-MS/MS for the simultaneous analysis of 17 diuretics in dietary supplements. HPLC conditions were set with a Capcell-pak C18, using a mobile phase consisting of gradient conditions, UV detection at 254 nm and validated for linearity (r(2)> 0.999), precision (CV ≤ 3%), recoveries (90.4-102.8%) and reproducibility. Identification and quantification of 17 diuretics were accomplished by ion-spray LC-MS/MS using multiple reaction monitoring (MRM). The chromatographic separation was carried out under the reversed-phase mechanism on an HSS-T3 column. The LC-MS/MS method was validated for linearity (r(2)> 0.99) and precision (CV Diuretics were not detected in all samples. Extraction recovery was also investigated and the extraction recoveries in different formulations were from 88% to 110% and from 81% to 116% using HPLC and LC-MS/MS, respectively. There was no significant difference in recoveries in the type of dietary supplements. Based on this result, the developed methods to monitor illegal drug adulterations in dietary supplements using HPLC and LC-MS/MS are simple, fast and reliable. Therefore, it is applicable to routine drug-adulteration screening.

First plasmas in the TJ-II flexible Heliac

International Nuclear Information System (INIS)

Alejaldre, C.; Alonso, J.; Almoguera, L.; Ascasibar, E.; Baciero, A.; Balbin, R.; Blaumoser, M.; Botija, J.; Branas, B.; Cal, E. de la; Cappa, A.; Carrasco, R.; Castejon, F.; Cepero, J.R.; Cremy, C.; Doncel, J.; Dulya, C.; Estrada, T.; Fernandez, A.; Frances, M.; Fuentes, C.; Garcia, A.; Garcia-Cortes, I.; Guasp, J.; Herranz, J.; Hidalgo, C.; Jimenez, J.A.; Kirpitchev, I.; Krivenski, V.; Labrador, I.; Lapayese, F.; Likin, K.; Liniers, M.; Lopez-Fraguas, A.; Lopez-Sanchez, A.; Luna, E. de la; Martin, R.; Martinez, A.; Medrano, M.; Mendez, P.; McCarthy, K.; Medina, F.; Milligen, B. van; Ochando, M.; Pacios, L.; Pastor, I.; Pedrosa, M.A.; Pena, A. de la; Portas, A.; Qin, J.; Rodriguez-Rodrigo, L.; Salas, A.; Sanchez, E.; Sanchez, J.; Tabares, F.; Tafalla, D.; Tribaldos, V.; Vega, J.; Zurro, B.; Akulina, D.; Fedyanin, O.I.; Grebenshchicov, S.; Kharchev, N.; Meshcheryakov, A.; Barth, R.; Dijk, G. van; Meiden, H. van der; Petrov, S.

1999-01-01

The first experimental campaign of the TJ-II stellarator has been conducted using electron cyclotron resonance heating (f=53.2 GHz, P ECRH approx. 250 kW) with a pulse length of Δt approx. (80-200) ms. The flexibility of the device has been used to study five different configurations varying plasma volume and rotational transform. In this paper, the main results of this campaign are presented and, in particular, the influence of plasma-wall interaction phenomena on TJ-II confinement is briefly discussed. (author)

Relationship among RR interval, optimal reconstruction phase, temporal resolution, and image quality of end-systolic reconstruction of coronary CT angiography in patients with high heart rates. In search of the optimal acquisition protocol

International Nuclear Information System (INIS)

Sano, Tomonari; Matsutani, Hideyuki; Kondo, Takeshi; Fujimoto, Shinichiro; Sekine, Takako; Arai, Takehiro; Morita, Hitomi; Takase, Shinichi

2011-01-01

The purpose of this study is to elucidate the relationship among RR interval (RR), the optimal reconstruction phase, and adequate temporal resolution (TR) to obtain coronary CT angiography images of acceptable quality using 64-multi detector-row CT (MDCT) (Aquilion 64) of end-systolic reconstruction in 407 patients with high heart rates. Image quality was classified into 3 groups [rank A (excellent): 161, rank B (acceptable): 207, and rank C (unacceptable): 39 patients]. The optimal absolute phase (OAP) significantly correlated with RR [OAP (ms)=119-0.286 RR (ms), r=0.832, p<0.0001], and the optimal relative phase (ORP) also significantly correlated with RR [ORP (%)=62-0.023 RR (ms), r=0.656, p<0.0001], and the correlation coefficient of OAP was significantly (p<0.0001) higher than that of ORP. The OAP range (±2 standard deviation (SD)) in which it is highly possible to get a static image was from [119-0.286 RR (ms)-46] to [119-0.286 RR (ms)+46]. The TR was significantly different among ranks A (97±22 ms), B (111±31 ms) and C (135±34 ms). The TR significantly correlated with RR in ranks A (TR=-16+0.149 RR, r=0.767, p<0.0001), B (TR=-15+0.166 RR, r=0.646, p<0.0001), and C (TR=52+0.117 RR, r=0.425, p=0.0069). Rank C was distinguished from ranks A or B by linear discriminate analysis (TR=-46+0.21 RR), and the discriminate rate was 82.6%. In conclusion, both the OAP and adequate TR depend on RR, and the OAP range (±2 SD) can be calculated using the formula [119-0.286 RR (ms)-46] to [119-0.286 RR (ms) +46], and an adequate TR value would be less than (-46+0.21 RR). (author)

Using Group II Introns for Attenuating the In Vitro and In Vivo Expression of a Homing Endonuclease.

Directory of Open Access Journals (Sweden)

Tuhin Kumar Guha

Full Text Available In Chaetomium thermophilum (DSM 1495 within the mitochondrial DNA (mtDNA small ribosomal subunit (rns gene a group IIA1 intron interrupts an open reading frame (ORF encoded within a group I intron (mS1247. This arrangement offers the opportunity to examine if the nested group II intron could be utilized as a regulatory element for the expression of the homing endonuclease (HEase. Constructs were generated where the codon-optimized ORF was interrupted with either the native group IIA1 intron or a group IIB type intron. This study showed that the expression of the HEase (in vivo in Escherichia coli can be regulated by manipulating the splicing efficiency of the HEase ORF-embedded group II introns. Exogenous magnesium chloride (MgCl2 stimulated the expression of a functional HEase but the addition of cobalt chloride (CoCl2 to growth media antagonized the expression of HEase activity. Ultimately the ability to attenuate HEase activity might be useful in precision genome engineering, minimizing off target activities, or where pathways have to be altered during a specific growth phase.

Relapsing-Remitting MS (RRMS)

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Analysis of perchlorate in foods and beverages by ion chromatography coupled with tandem mass spectrometry (IC-ESI-MS/MS)

Energy Technology Data Exchange (ETDEWEB)

El Aribi, Houssain [Applied Biosystems/MDS Sciex, 71 Four Valley Drive, Concord, Ont., L4K 4V8 (Canada)]. E-mail: houssain.aribi@sciex.com; Le Blanc, Yves J.C. [Applied Biosystems/MDS Sciex, 71 Four Valley Drive, Concord, Ont., L4K 4V8 (Canada); Antonsen, Stephen [Dionex Canada Ltd., 1540 Cornwall Road, Oakville, Ont., L6J 7W5 (Canada); Sakuma, Takeo [Applied Biosystems/MDS Sciex, 71 Four Valley Drive, Concord, Ont., L4K 4V8 (Canada)

2006-05-10

A new IC-ESI-MS/MS method, with simple sample preparation procedure, has been developed for quantification and confirmation of perchlorate (ClO{sub 4} {sup -}) anions in water, fresh and canned food, wine and beer samples at low part-per-trillion (ng l{sup -1}) levels. To the best of our knowledge, this is the first time an analytical method is used for determination of perchlorate in wine and beer samples. The IC-ESI-MS/MS instrumentation consisted of an ICS-2500 ion chromatography (IC) system coupled to either an API 2000{sup TM} or an API 3200{sup TM} mass spectrometer. The IC-ESI-MS/MS system was optimized to monitor two pairs of precursor and fragment ion transitions, i.e., multiple reaction monitoring (MRM). All samples had oxygen-18 isotope labeled perchlorate internal standard (ISTD) added prior to extraction. Chlorine isotope ratio ({sup 35}Cl/{sup 37}Cl) was used as a confirmation tool. The transition of {sup 35}Cl{sup 16}O{sub 4} {sup -} (m/z 98.9) into {sup 35}Cl{sup 16}O{sub 3} {sup -} (m/z 82.9) was monitored for quantifying the main analyte; the transition of {sup 37}Cl{sup 16}O{sub 4} {sup -} (m/z 100.9) into {sup 37}Cl{sup 16}O{sub 3} {sup -} (m/z 84.9) was monitored for examining a proper isotopic abundance ratio of {sup 35}Cl/{sup 37}Cl; and the transition of {sup 35}Cl{sup 18}O{sub 4} {sup -} (m/z 107.0) into {sup 35}Cl{sup 18}O{sub 3} {sup -} (m/z 89.0) was monitored for quantifying the internal standard. The minimum detection limit (MDL) for this method in de-ionized water is 5 ng l{sup -1} (ppt) using the API 2000{sup TM} mass spectrometer and 0.5 ng l{sup -1} using the API 3200{sup TM} mass spectrometer. Over 350 food and beverage samples were analyzed mostly in triplicate. Except for four, all samples were found to contain measurable amounts of perchlorate. The levels found ranged from 5 ng l{sup -1} to 463.5 {+-} 6.36 {mu}g kg{sup -1} using MRM 98.9 {sup {yields}} 82.9 and 100 {mu}l injection.

MS-SQL data base programming

Energy Technology Data Exchange (ETDEWEB)

Noh, Chang Bae; Kim, Nam Jung; Lee, Hyeong Gyo

2002-07-15

This is about MS-SQL data base programming which is divided into thirteen chapters. The contents of this book are to understand MS-SQL 2000 DBMS with its composition, new function and history of MS-SQL, to learn conception of data base, install, run and closing of MS-SQL 2000 DBMS, to deal with the basic of MS-SQL DBMS, to handle the intermediate level of MS-SQL DBMS, to deal with MS-SQL DBMS in advanced level, to practice query like changing data base and checking of data lists, function on its use and data diff, get date, date add, char, upper and system function, set-up of MS-SQL ODBC, constructing of web server of windows 2000, web programming using visual studio.net.making board and making reference room.

MS-SQL data base programming

International Nuclear Information System (INIS)

Noh, Chang Bae; Kim, Nam Jung; Lee, Hyeong Gyo

2002-07-01

This is about MS-SQL data base programming which is divided into thirteen chapters. The contents of this book are to understand MS-SQL 2000 DBMS with its composition, new function and history of MS-SQL, to learn conception of data base, install, run and closing of MS-SQL 2000 DBMS, to deal with the basic of MS-SQL DBMS, to handle the intermediate level of MS-SQL DBMS, to deal with MS-SQL DBMS in advanced level, to practice query like changing data base and checking of data lists, function on its use and data diff, get date, date add, char, upper and system function, set-up of MS-SQL ODBC, constructing of web server of windows 2000, web programming using visual studio.net.making board and making reference room.

Analytical Method Details (MS): SE2_MS3 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available 00.0-1500.0); 2: ITMS + c norm !corona !pi Dep MS/MS Most intense ion from (1)., Rejected mass=284.2000;300.2000;328.2000;344.2000;372.2000;388.2000;416.3000;432.3000;460.0000. ...

Identification and quantification of metallothionein isoforms and superoxide dismutase in spiked liver extracts using HPLC-ESI-MS offline coupling and HPLC-ICP-MS online coupling.

Science.gov (United States)

Nischwitz, V; Michalke, B; Kettrup, A

2003-01-01

A two-dimensional chromatographic method for the characterization of metallothionein isoforms (MT) and superoxide dismutase (SOD) in spiked liver extracts was developed for the optimization of extraction procedures from liver samples. Element-specific detection (ICP-MS) and molecule-specific detection (ESI-MS) were applied for maximum species information. A special focus was laid on the quantitative data evaluation (species stoichiometry, calibration with and without matrix, recovery), which is neglected in most MT/SOD publications with hyphenated techniques. Linearity, precision (residual standard deviation of calibration curves <10%), and detection limits (<0.6 mg L(-1) for MT isoforms and 13 mg L(-1) for SOD) prove the suitability of the method for quantification. An alternative quantification is proposed for the extension towards other lesser or even unknown trace element species, especially the native porcine MT and SOD.

Discovery and development of the N-terminal procollagen type II (NPII) biomarker: a tool for measuring collagen type II synthesis.

Science.gov (United States)

Nemirovskiy, O V; Sunyer, T; Aggarwal, P; Abrams, M; Hellio Le Graverand, M P; Mathews, W R

2008-12-01

Progression of joint damage in osteoarthritis (OA) is likely to result from an imbalance between cartilage degradation and synthesis processes. Markers reflecting these two components appear to be promising in predicting the rate of OA progression. Both N- and C-terminal propeptides of type II collagen reflect the rates of collagen type II synthesis. The ability to quantify the procollagen peptides in biological fluids would enable a better understanding of OA disease pathology and provide means for assessing the proof of mechanism of anabolic disease modifying OA drugs (DMOADs). A polyclonal antibody that recognizes the sequence GPKGQKGEPGDIKDI in the propeptide region of rat, dog, and human type II collagen was raised in chicken and peptide-affinity purified. The immunoaffinity liquid chromatography mass spectrometry (LC-MS/MS) was used to extensively characterize N-terminal procollagen type II (NPII) peptides found in biological fluids. The novel competition enzyme-linked immunosorbent assay (ELISA) assay was developed to quantitatively measure the NPII peptides. Several peptides ranging from 17 to 41 amino acids with various modifications including hydroxylations on proline and lysine residues, oxidation of lysines to allysines, and attachments of glucose and galactose moieties to hydroxylysines were identified in a simple system such as ex vivo cultures of human articular cartilage (HAC) explants as well as in more complex biological fluids such as human urine and plasma. A competitive ELISA assay has been developed and applied to urine, plasma, and synovial fluid matrices in human, rat and dog samples. A novel NPII assay has been developed and applied to OA and normal human subjects to understand the changes in collagen type II synthesis related to the pathology of OA.

Relapsing-Remitting MS (RRMS)

Medline Plus

Full Text Available ... Treating MS d Comprehensive Care Developing a Healthcare Team Make the Most of Your Doctor Visits Advance Medical Directives d Find an MS Care Provider Partners in MS Care d Managing Relapses Plasmapheresis d Rehabilitation Functional Electrical Stimulation (FES) ...

[2 × 2] Molecular Grids of Ni(II and Zn(II with Redox-Active 1,4-Pyrazine-Bis(thiosemicarbazone Ligands

Directory of Open Access Journals (Sweden)

Natalia Arefyeva

2018-05-01

Full Text Available Tetranuclear complexes [M4(LR4] with M = Ni(II or Zn(II, with a [2 × 2] grid-type structure, were assembled in good yields and purity from the easily accessible but unprecedented pyrazine-bridged bis(thiosemicarbazone protoligands (ligand precursors H2LR (1,4-pyrazine-2,5-bis(R-carbaldehyde-thiosemicarbazone; R = Me, Et, iPr, or Ph. The complexes were characterised in solution by NMR, MS, IR, and UV-Vis absorption spectroscopy and (spectroelectrochemical methods. HR-MS spectra unequivocally reveal that the tetranuclear species are very stable in solution and any measurements represent these species. Only at higher temperatures (fragmentation in solution: MS and in the solid: TG-DTA or upon the addition of protons (acidic UV-Vis titrations can the tetrameric entities be decomposed. Single crystal XRD measurement remained preliminary. Rapid loss of co-crystallised solvent molecules within the [2 × 2] grid-type structures resulted in crystals of very poor quality, but the results were qualitatively in line with spectroscopy, electrochemistry, and quantum chemical (DFT calculations. IR and NMR spectroscopy point clearly to a thiolate coordination of dianionic (deprotonated ligands. The electrochemistry reveals four electronically coupled and reversible one-electron reductions centred largely at the pyrazine bridges. EPR and UV-Vis spectroelectrochemical measurements in combination with DFT calculation support the assignment.

Simultaneous determination of amino acid and monoamine neurotransmitters in PC12 cells and rats models of Parkinson's disease using a sensitizing derivatization reagent by UHPLC-MS/MS.

Science.gov (United States)

Zhao, Xian-En; Zhu, Shuyun; Yang, Hongmei; You, Jinmao; Song, Fengrui; Liu, Zhiqiang; Liu, Shuying

2015-07-15

Multi-analytes simultaneous monitoring of amino acid and monoamine neurotransmitters (NTs) has important scientific significance for their related pathology, physiology and drug screening. In this work, in virtue of a mass spectrometry sensitizing reagent 10-ethyl-acridone-3-sulfonyl chloride (EASC) as derivatization reagent, an Ultra High Performance Liquid Chromatography-Tandem Mass Spectrometry (UHPLC-MS/MS) method was developed and validated for simultaneous determination of six amino acid NTs, two monoamine ones and its one metabolite. The simple and rapid derivatization reaction was innovatively combined with plasma preparation by using EASC acetonitrile solution as protein precipitant. This interesting combination brought the advantages of speediness, simpleness and high-throughput in a cost-effective way. Under the optimized conditions, LODs (0.004-3.80nM) and LOQs (0.014-13.3nM) of EASC derivatized-NTs were calculated and found to be significantly lower than those of direct UHPLC-MS/MS detection about 11.5-275.0 and 14.4-371.4 times, respectively. Moreover, EASC derivatization significantly improved chromatographic resolution and matrix effect when compared with direct UPLC-MS/MS detection method without derivatization. Meanwhile, it also brought acceptable precision (3.0-13.0%, peak area CVs%), accuracy (86.4-112.9%), recovery (88.3-107.8%) and stability (3.8-8.5%, peak area CVs%) results. This method was successfully applied for the antiparkinsonian effect evaluation of levodopa and Ginsenoside Rg1 using PC12 cells and rats models by measuring multiple NTs. This provided a new method for the NTs related studies in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

MS Based Metabonomics

Energy Technology Data Exchange (ETDEWEB)

Want, Elizabeth J.; Metz, Thomas O.

2010-03-01

Metabonomics is the latest and least mature of the systems biology triad, which also includes genomics and proteomics, and has its origins in the early orthomolecular medicine work pioneered by Linus Pauling and Arthur Robinson. It was defined by Nicholson and colleagues in 1999 as the quantitative measurement of perturbations in the metabolite complement of an integrated biological system in response to internal or external stimuli, and is often used today to describe many non-global types of metabolite analyses. Applications of metabonomics are extensive and include toxicology, nutrition, pharmaceutical research and development, physiological monitoring and disease diagnosis. For example, blood samples from millions of neonates are tested routinely by mass spectrometry (MS) as a diagnostic tool for inborn errors of metabolism. The metabonome encompasses a wide range of structurally diverse metabolites; therefore, no single analytical platform will be sufficient. Specialized sample preparation and detection techniques are required, and advances in NMR and MS technologies have led to enhanced metabonome coverage, which in turn demands improved data analysis approaches. The role of MS in metabonomics is still evolving as instrumentation and software becomes more sophisticated and as researchers realize the strengths and limitations of current technology. MS offers a wide dynamic range, high sensitivity, and reproducible, quantitative analysis. These attributes are essential for addressing the challenges of metabonomics, as the range of metabolite concentrations easily exceeds nine orders of magnitude in biofluids, and the diversity of molecular species ranges from simple amino and organic acids to lipids and complex carbohydrates. Additional challenges arise in generating a comprehensive metabolite profile, downstream data processing and analysis, and structural characterization of important metabolites. A typical workflow of MS-based metabonomics is shown in Figure

OPTIMIZATION OF NICKEL (II) AND CHROMIUM (III) REMOVAL ...

African Journals Online (AJOL)

RSM)was used to study the effect of three adsorption variables (pH, initial concentration, and adsorbent dosage) in order to determine the optimum process conditions for the adsorptions of Ni (II) and Cr (III) onto sulphuric acid modified sorghum ...

Architecture of the RNA polymerase II-TFIIF complex revealed by cross-linking and mass spectrometry

DEFF Research Database (Denmark)

Chen, Zhuo Angel; Jawhari, Anass; Fischer, Lutz

2010-01-01

Higher-order multi-protein complexes such as RNA polymerase II (Pol II) complexes with transcription initiation factors are often not amenable to X-ray structure determination. Here, we show that protein cross-linking coupled to mass spectrometry (MS) has now sufficiently advanced as a tool to ex...

Optimal Solutions of Multiproduct Batch Chemical Process Using Multiobjective Genetic Algorithm with Expert Decision System

Science.gov (United States)

Mokeddem, Diab; Khellaf, Abdelhafid

2009-01-01

Optimal design problem are widely known by their multiple performance measures that are often competing with each other. In this paper, an optimal multiproduct batch chemical plant design is presented. The design is firstly formulated as a multiobjective optimization problem, to be solved using the well suited non dominating sorting genetic algorithm (NSGA-II). The NSGA-II have capability to achieve fine tuning of variables in determining a set of non dominating solutions distributed along the Pareto front in a single run of the algorithm. The NSGA-II ability to identify a set of optimal solutions provides the decision-maker DM with a complete picture of the optimal solution space to gain better and appropriate choices. Then an outranking with PROMETHEE II helps the decision-maker to finalize the selection of a best compromise. The effectiveness of NSGA-II method with multiojective optimization problem is illustrated through two carefully referenced examples. PMID:19543537

LC-MS-MS identification of drug metabolites obtained by metalloporphyrin mediated oxidation

Directory of Open Access Journals (Sweden)

Maurin Andrea J. M.

2003-01-01

Full Text Available In this paper we report the application of liquid chromatography-mass spectrometry (LC-MS-MS to the identification of the products formed by oxidation of albendazole and disopyramide with metalloporphyrins in dichloroethane, using iodosylbenzene as an oxygen donor. Our results show that LC-MS-MS is a powerful tool to study the in vitro metabolism of drugs, allowing the identification of known and unknown metabolites. In addition, it was observed that the catalyst system used resulted in the formation of the same metabolites as obtained in vivo, although for disopyramide other products were also observed.

DBS-LC-MS/MS assay for caffeine: validation and neonatal application.

Science.gov (United States)

Bruschettini, Matteo; Barco, Sebastiano; Romantsik, Olga; Risso, Francesco; Gennai, Iulian; Chinea, Benito; Ramenghi, Luca A; Tripodi, Gino; Cangemi, Giuliana

2016-09-01

DBS might be an appropriate microsampling technique for therapeutic drug monitoring of caffeine in infants. Nevertheless, its application presents several issues that still limit its use. This paper describes a validated DBS-LC-MS/MS method for caffeine. The results of the method validation showed an hematocrit dependence. In the analysis of 96 paired plasma and DBS clinical samples, caffeine levels measured in DBS were statistically significantly lower than in plasma but the observed differences were independent from hematocrit. These results clearly showed the need for extensive validation with real-life samples for DBS-based methods. DBS-LC-MS/MS can be considered to be a good alternative to traditional methods for therapeutic drug monitoring or PK studies in preterm infants.

Cd(II and Pb(II complexes of the polyether ionophorous antibiotic salinomycin

Directory of Open Access Journals (Sweden)

Tanabe Makoto

2011-09-01

Full Text Available Abstract Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II ions in in vivo experiments, despite so far no Pb(II-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II and lead(II. Results New metal(II complexes of the polyether ionophorous antibiotic salinomycin with Cd(II and Pb(II ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa undergoes a reaction with heavy metal(II ions to form [Cd(Sal2(H2O2] (1 and [Pb(Sal(NO3] (2, respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock

Cd(II) and Pb(II) complexes of the polyether ionophorous antibiotic salinomycin

Science.gov (United States)

2011-01-01

Background The natural polyether ionophorous antibiotics are used for the treatment of coccidiosis in poultry and ruminants. They are effective agents against infections caused by Gram-positive microorganisms. On the other hand, it was found that some of these compounds selectively bind lead(II) ions in in vivo experiments, despite so far no Pb(II)-containing compounds of defined composition have been isolated and characterized. To assess the potential of polyether ionophores as possible antidotes in the agriculture, a detailed study on their in vitro complexation with toxic metal ions is required. In the present paper we report for the first time the preparation and the structure elucidation of salinomycin complexes with ions of cadmium(II) and lead(II). Results New metal(II) complexes of the polyether ionophorous antibiotic salinomycin with Cd(II) and Pb(II) ions were prepared and structurally characterized by IR, FAB-MS and NMR techniques. The spectroscopic information and elemental analysis data reveal that sodium salinomycin (SalNa) undergoes a reaction with heavy metal(II) ions to form [Cd(Sal)2(H2O)2] (1) and [Pb(Sal)(NO3)] (2), respectively. Abstraction of sodium ions from the cavity of the antibiotic is occurring during the complexation reaction. Salinomycin coordinates with cadmium(II) ions as a bidentate monoanionic ligand through the deprotonated carboxylic moiety and one of the hydroxyl groups to yield 1. Two salinomycin anions occupy the equatorial plane of the Cd(II) center, while two water molecules take the axial positions of the inner coordination sphere of the metal(II) cation. Complex 2 consists of monoanionic salinomycin acting in polydentate coordination mode in a molar ratio of 1: 1 to the metal ion with one nitrate ion for charge compensation. Conclusion The formation of the salinomycin heavy metal(II) complexes indicates a possible antidote activity of the ligand in case of chronic/acute intoxications likely to occur in the stock farming

Optimal Cost Avoidance Investment and Pricing Strategies for Performance-Based Post-Production Service Contracts

Science.gov (United States)

2011-04-30

a BS degree in Mathematics and an MS degree in Statistics and Financial and Actuarial Mathematics from Kiev National Taras Shevchenko University...degrees from Rutgers University in Industrial Engineering (PhD and MS) and Statistics (MS) and from Universidad Nacional Autonoma de Mexico in Actuarial ...Science. His research efforts focus on developing mathematical models for the analysis, computation, and optimization of system performance with

Determination of Lead(II), Cadmium(II) and Copper(II) in Waste-Water and Soil Extracts on Mercury Film Screen-Printed Carbon Electrodes Sensor

International Nuclear Information System (INIS)

Mohd Fairulnizal Md Noh; Tothill, I.E.

2011-01-01

A sensor incorporating a three electrodes configuration have been fabricated using low cost screen-printing technology. These electrodes couples with Square Wave Stripping Voltammetry (SWSV) has provided a convenient screening tool for on-site detection of trace levels of Pb(II), Cd(II) and Cu(II). Modification of the graphite carbon surface based on in situ deposition of mercury film has been carried out. By appropriate choice of supporting medium and optimized parameters setting such as amount of mercury used the deposition potential, deposition time, frequency and scan rate, well resolved and reproducible response for Pb(II), Cd(II) and Cu(II) were obtained. The performance characteristics of the developed mercury film screen printed carbon electrode (MFSPCE) for 120 s deposition time showed that the linear range for Cd(II), Pb(II) and Cu(II) were 10 to 200 μg L -1 . The detection limit recorded for Cd(II), Pb(II) and Cu(II) were 2, 1 and 5 μg L -1 with relative standard deviation (RSD) of 6.5 %, 6.9 % and 7.5 %, respectively. Successful applications of the sensing device to waste-water and extracted soil samples were demonstrated. (author)

Spectral, thermal, electrochemical and analytical studies on Cd(II) and Hg(II) thiosemicarbazone complexes

Science.gov (United States)

El-Asmy, A. A.; El-Gammal, O. A.; Saleh, H. S.

2008-11-01

The coordination characteristic of the investigated thiosemicarbazones towards hazard pollutants, Cd(II) and Hg(II), becomes the first goal. Their complexes have been studied by microanalysis, thermal, electrochemical and spectral (electronic, IR and MS) studies. The substitutent (salicylaldehyde, acetophenone, benzophenone, o-hydroxy- p-methoxybenzophenone or diacetylmonoxime) plays an important role in the complex formation. The coordination sites were the S for thiosemicarbazide (HTS); NN for benzophenone thiosemicarbazone (HBTS); NS for acetophenone thiosemicarbazone (HATS) and salicylaldehyde thiosemicarbazone (H 2STS); NNS or NSO for diacetylmonoxime thiosemicarbazone (H 2DMTS). The stability constants of Hg(II) complexes were higher than Cd(II). The kinetic and thermodynamic parameters for the different thermal decomposition steps in the complexes have been evaluated. The activation energy values of the first step ordered the complexes as: [Cd(H 2STS)Cl 2]H 2O > [Cd(H 2DAMTS)Cl 2] > [Cd(HBTS) 2Cl 2]2H 2O > [Cd(HATS) 2Cl 2]. The CV of [Cd(H 2STS)Cl 2]H 2O and [Hg(HBTS)Cl 2] were recorded. The use of H 2DMTS as a new reagent for the separation and determination of Cd(II) ions from water and some synthetic samples using flotation technique is aimed to be discussed.

Exploring the Metabolism of (+-[18F]Flubatine In Vitro and In Vivo: LC-MS/MS Aided Identification of Radiometabolites in a Clinical PET Study †

Directory of Open Access Journals (Sweden)

Friedrich-Alexander Ludwig

2018-02-01

Full Text Available Both (+-[18F]flubatine and its enantiomer (−-[18F]flubatine are radioligands for the neuroimaging of α4β2 nicotinic acetylcholine receptors (nAChRs by positron emission tomography (PET. In a clinical study in patients with early Alzheimer’s disease, (+-[18F]flubatine ((+-[18F]1 was examined regarding its metabolic fate, in particular by identification of degradation products detected in plasma and urine. The investigations included an in vivo study of (+-flubatine ((+-1 in pigs and structural elucidation of formed metabolites by LC-MS/MS. Incubations of (+-1 and (+-[18F]1 with human liver microsomes were performed to generate in vitro metabolites, as well as radiometabolites, which enabled an assignment of their structures by comparison of LC-MS/MS and radio-HPLC data. Plasma and urine samples taken after administration of (+-[18F]1 in humans were examined by radio-HPLC and, on the basis of results obtained in vitro and in vivo, formed radiometabolites were identified. In pigs, (+-1 was monohydroxylated at different sites of the azabicyclic ring system of the molecule. Additionally, one intermediate metabolite underwent glucuronidation, as also demonstrated in vitro. In humans, a fraction of 95.9 ± 1.9% (n = 10 of unchanged tracer remained in plasma, 30 min after injection. However, despite the low metabolic degradation, both radiometabolites formed in humans could be characterized as (i a product of C-hydroxylation at the azabicyclic ring system, and (ii a glucuronide conjugate of the precedingly-formed N8-hydroxylated (+-[18F]1.

Optimization of Feasibility Stage for Hydrogen/Deuterium Exchange Mass Spectrometry

Science.gov (United States)

Hamuro, Yoshitomo; Coales, Stephen J.

2018-03-01

The practice of HDX-MS remains somewhat difficult, not only for newcomers but also for veterans, despite its increasing popularity. While a typical HDX-MS project starts with a feasibility stage where the experimental conditions are optimized and the peptide map is generated prior to the HDX study stage, the literature usually reports only the HDX study stage. In this protocol, we describe a few considerations for the initial feasibility stage, more specifically, how to optimize quench conditions, how to tackle the carryover issue, and how to apply the pepsin specificity rule. Two sets of quench conditions are described depending on the presence of disulfide bonds to facilitate the quench condition optimization process. Four protocols are outlined to minimize carryover during the feasibility stage: (1) addition of a detergent to the quench buffer, (2) injection of a detergent or chaotrope to the protease column after each sample injection, (3) back-flushing of the trap column and the analytical column with a new plumbing configuration, and (4) use of PEEK (or PEEK coated) frits instead of stainless steel frits for the columns. The application of the pepsin specificity rule after peptide map generation and not before peptide map generation is suggested. The rule can be used not only to remove falsely identified peptides, but also to check the sample purity. A well-optimized HDX-MS feasibility stage makes subsequent HDX study stage smoother and the resulting HDX data more reliable. [Figure not available: see fulltext.

FREE RADICAL SCAVENGING CAPACITY OF PAPAVER SOMNIFERUM L. AND DETERMINATION OF PHARMACOLOGICALLY ACTIVE ALKALOIDS USING CAPILLARY ELECTROPHORESIS

Directory of Open Access Journals (Sweden)

Marián Valko

2012-02-01

Full Text Available The free radical generation is related to the oxidation process in biological systems as well as in foods. It was found that oxidation is affected by antioxidants that can act as radical scavengers. Objective of the present work was to study the free radical scavenging capacity of opium poppy (Papaver somniferum L. extract by using the DPPH test and to verify the suitability of the micellar electrokinetic capillary chromatography (MEKC technique for analytical assessment and determination of three major poppy alkaloids (thebaine, morphine and papaverine. Because of its generally high separation efficiency, the MEKC is successfully used for analytical evaluation of biologically active substances usually without special claims for sample preparation. The results of DPPH test have shown that poppy contains components capable of terminating free radicals. We have confirmed that nature of the solvent used for the electrophoretic medium in MEKC has a strong influence on the separation efficiency. In our experiments, the most effective solvent was mixture of water to acetonitrile (ratio 4:6.

Optimization of DSC MRI Echo Times for CBV Measurements Using Error Analysis in a Pilot Study of High-Grade Gliomas.

Science.gov (United States)

Bell, L C; Does, M D; Stokes, A M; Baxter, L C; Schmainda, K M; Dueck, A C; Quarles, C C

2017-09-01

The optimal TE must be calculated to minimize the variance in CBV measurements made with DSC MR imaging. Simulations can be used to determine the influence of the TE on CBV, but they may not adequately recapitulate the in vivo heterogeneity of precontrast T2*, contrast agent kinetics, and the biophysical basis of contrast agent-induced T2* changes. The purpose of this study was to combine quantitative multiecho DSC MRI T2* time curves with error analysis in order to compute the optimal TE for a traditional single-echo acquisition. Eleven subjects with high-grade gliomas were scanned at 3T with a dual-echo DSC MR imaging sequence to quantify contrast agent-induced T2* changes in this retrospective study. Optimized TEs were calculated with propagation of error analysis for high-grade glial tumors, normal-appearing white matter, and arterial input function estimation. The optimal TE is a weighted average of the T2* values that occur as a contrast agent bolus transverses a voxel. The mean optimal TEs were 30.0 ± 7.4 ms for high-grade glial tumors, 36.3 ± 4.6 ms for normal-appearing white matter, and 11.8 ± 1.4 ms for arterial input function estimation (repeated-measures ANOVA, P optimal TE values for high-grade gliomas, and mean values of all 3 ROIs were statistically significant. The optimal TE for the arterial input function estimation is much shorter; this finding implies that quantitative DSC MR imaging acquisitions would benefit from multiecho acquisitions. In the case of a single-echo acquisition, the optimal TE prescribed should be 30-35 ms (without a preload) and 20-30 ms (with a standard full-dose preload). © 2017 by American Journal of Neuroradiology.

Nickel(II) complexes containing ONS donor ligands: Synthesis ...

Indian Academy of Sciences (India)

MS received 23 July 2014; revised 28 November 2014; accepted 28 November 2014 ... Nickel(II) complexes; X-ray structure; Kumada-Corriu reaction; Suzuki reaction; ...... 29 75. 37. Kovala-Demertzi D, Demertzis M A, Miller J R,. Papadopoulou C ... Biochem. 86 555. 38. Bellamy L J 1985 In The Infrared Spectra of Complex.

First plasmas in the TJ-II flexible Heliac

NARCIS (Netherlands)

Alejaldre, C.; Alonso, J.; Almoguera, L.; Ascasibar, E.; Baciero, A.; Balbin, R.; Blaumoser, M.; Botija, J.; Branas, B.; De La Cal, E.; Cappa, A.; Carrasco, R.; Castejon, F.; Cepero, J. R.; Cremy, C.; Doncel, J.; Dulya, C.; Estrada, T.; Fernandez, A.; Frances, M.; Fuentes, C.; Garcia, A.; Garcia-Cortes, I.; Guasp, J.; Herranz, J.; Hidalgo, C.; Jimenez, J. A.; Kirpitchev, I.; Krivenski, V.; Labrador, I.; Lapayese, F.; Likin, K.; Liniers, M.; Lopez-Fraguas, A.; Lopez-Sanchez, A.; de la Luna, E.; Martin, R.; Martinez, A.; Medrano, M.; Mendez, P.; McCarthy, K.; Medina, F.; van Milligen, B.; Ochando, M.; Pacios, L.; Pastor, I.; Pedrosa, M. A.; de la Pena, A.; Portas, A.; Qin, J.; Rodriguez-Rodrigo, L.; Salas, A.; Sanchez, E.; Sanchez, J.; Tabares, F.; Tafalla, D.; Tribaldos, V.; Vaga, J.; Zurro, B.; Akulina, D.; Fadyanin, O. I.; Grebenshchicov, S.; Kharchev, N.; Meshcheryakov, A.; Barth, R.; van Dijk, G.; van der Meiden, H.; Petrov, S.

1999-01-01

The first experimental campaign of the TJ-II stellarator has been conducted using electron cyclotron resonance heating (f = 53.2 GHz, P-ECRH approximate to 250 kW) with a pulse length of Delta t approximate to (80-200) ms. The flexibility of the device has been used to study five different

Analytical Method Details (MS): SE29_MS1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available SE29_MS1 LC-FT-ICR-MS ESI positive method 1 Agilent1100 HPLC (Agilent), LTQ-FT (The... (100mg) are solved in 300uL 80% methanol solution. 20uL sample is injected into HPLC after 0.2um membrane filter treatment. HPLC

Mo/Si multilayers with enhanced TiO II- and RuO II-capping layers

Science.gov (United States)

Yulin, Sergiy; Benoit, Nicolas; Feigl, Torsten; Kaiser, Norbert; Fang, Ming; Chandhok, Manish

2008-03-01

The lifetime of Mo/Si multilayer-coated projection optics is one of the outstanding issues on the road of commercialization of extreme-ultraviolet lithography (EUVL). The application of Mo/Si multilayer optics in EUVL requires both sufficient radiation stability and also the highest possible normal-incidence reflectivity. A serious problem of conventional high-reflective Mo/Si multilayers capped by silicon is the considerable degradation of reflective properties due to carbonization and oxidation of the silicon surface layer under exposure by EUV radiation. In this study, we focus on titanium dioxide (TiO II) and ruthenium dioxide (RuO II) as promising capping layer materials for EUVL multilayer coatings. The multilayer designs as well as the deposition parameters of the Mo/Si systems with different capping layers were optimized in terms of maximum peak reflectivity at the wavelength of 13.5 nm and longterm stability under high-intensive irradiation. Optimized TiO II-capped Mo/Si multilayer mirrors with an initial reflectivity of 67.0% presented a reflectivity drop of 0.6% after an irradiation dose of 760 J/mm2. The reflectivity drop was explained by the partial oxidation of the silicon sub-layer. No reflectivity loss after similar irradiation dose was found for RuO II-capped Mo/Si multilayer mirrors having initial peak reflectivity of 66%. In this paper we present data on improved reflectivity of interface-engineered TiO II- and RuO II-capped Mo/Si multilayer mirrors due to the minimization of both interdiffusion processes inside the multilayer stack and absorption loss in the oxide layer. Reflectivities of 68.5% at the wavelength of 13.4 nm were achieved for both TiO II- and RuO II-capped Mo/Si multilayer mirrors.

FASTRAN II - FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS (UNIX VERSION)

Science.gov (United States)

Newman, J. C.

1994-01-01

loads may be either tensile or compressive. Several standardized aircraft flight-load histories, such as TWIST, Mini-TWIST, FALSTAFF, Inverted FALSTAFF, Felix and Gaussian, are included as options. FASTRAN II also includes two other methods that will help the user input spectrum load histories. The two methods are: (1) a list of stress points, and (2) a flight-by-flight history of stress points. Examples are provided in the user manual. Developed as a research program, FASTRAN II has successfully predicted crack growth in many metallic materials under various aircraft spectrum loading. A computer program DKEFF which is a part of the FASTRAN II package was also developed to analyze crack growth rate data from laboratory specimens to obtain the effective stress-intensity factor against crack growth rate relations used in FASTRAN II. FASTRAN II is written in standard FORTRAN 77. It has been successfully compiled and implemented on Sun4 series computers running SunOS and on IBM PC compatibles running MS-DOS using the Lahey F77L FORTRAN compiler. Sample input and output data are included with the FASTRAN II package. The UNIX version requires 660K of RAM for execution. The standard distribution medium for the UNIX version (LAR-14865) is a .25 inch streaming magnetic tape cartridge in UNIX tar format. It is also available on a 3.5 inch diskette in UNIX tar format. The standard distribution medium for the MS-DOS version (LAR-14944) is a 5.25 inch 360K MS-DOS format diskette. The contents of the diskette are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. The program was developed in 1984 and revised in 1992. Sun4 and SunOS are trademarks of Sun Microsystems, Inc. IBM PC is a trademark of International Business Machines Corp. MS-DOS is a trademark of Microsoft, Inc. F77L is a trademark of the Lahey Computer Systems, Inc. UNIX is a registered trademark of AT&T Bell Laboratories. PKWARE and PKUNZIP are trademarks of PKWare

Optimization of Biochemical Screening Methods for Volatile and Unstable Sesquiterpenoids Using HS-SPME-GC-MS

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Trine Bundgaard Andersen

2015-06-01

Full Text Available HS-SPME-GC-MS has been suggested as a fast and robust analytical platform for the product characterization of sesquiterpene synthases. The choice of fiber and injection temperature can have a significant effect on the observed product profile, due to the chemical rearrangements that can occur on the fiber material. Here we present a systematic study on the effects of fiber choice and injection port temperature on the observed sesquiterpenoid profile of four sesquiterpene synthases expressed in Nicotiana benthamiana. We found that the absorbent material PDMS was much less likely to support acid-induced rearrangement of sesquiterpenoids when compared to the adsorbent materials PDMS/DVB, PDMS/CAR, and PDMS/CAR/DVB. Furthermore, utilizing an injection port temperature at 160 °C almost eliminated the inherent thermal instability of germacrene sesquiterpenoids. Thus, for fast screening of sesquiterpene synthases, the results suggest that PDMS fibers and an injection temperature of 160 °C provide a fast and reproducible HS-SPME GC-MS method when using H2 as carrier gas.

Validation of a LC-MS/MS method for quantifying urinary nicotine, six nicotine metabolites and the minor tobacco alkaloids--anatabine and anabasine--in smokers' urine.

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James E McGuffey

Full Text Available Tobacco use is a major contributor to premature morbidity and mortality. The measurement of nicotine and its metabolites in urine is a valuable tool for evaluating nicotine exposure and for nicotine metabolic profiling--i.e., metabolite ratios. In addition, the minor tobacco alkaloids--anabasine and anatabine--can be useful for monitoring compliance in smoking cessation programs that use nicotine replacement therapy. Because of an increasing demand for the measurement of urinary nicotine metabolites, we developed a rapid, low-cost method that uses isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS for simultaneously quantifying nicotine, six nicotine metabolites, and two minor tobacco alkaloids in smokers' urine. This method enzymatically hydrolyzes conjugated nicotine (primarily glucuronides and its metabolites. We then use acetone pretreatment to precipitate matrix components (endogenous proteins, salts, phospholipids, and exogenous enzyme that may interfere with LC-MS/MS analysis. Subsequently, analytes (nicotine, cotinine, hydroxycotinine, norcotinine, nornicotine, cotinine N-oxide, nicotine 1'-N-oxide, anatabine, and anabasine are chromatographically resolved within a cycle time of 13.5 minutes. The optimized assay produces linear responses across the analyte concentrations typically found in urine collected from daily smokers. Because matrix ion suppression may influence accuracy, we include a discussion of conventions employed in this procedure to minimize matrix interferences. Simplicity, low cost, low maintenance combined with high mean metabolite recovery (76-99%, specificity, accuracy (0-10% bias and reproducibility (2-9% C.V. make this method ideal for large high through-put studies.

A novel HPLC-MS/MS method for the simultaneous determination of astemizole and its major metabolite in dog or monkey plasma and application to pharmacokinetics.

Science.gov (United States)

Back, Hyun-moon; Lee, Jong-Hwa; Chae, Jung-woo; Song, Byungjeong; Seo, Joung-Wook; Yun, Hwi-yeol; Kwon, Kwang-il

2015-10-10

Astemizole (AST), a second-generation antihistamine, is metabolized to desmethyl astemizole (DEA), and although it has been removed from the market for inducing QT interval prolongation, it has reemerged as a potential anticancer and antimalarial agent. This report describes a novel high-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) method for simultaneously determining the concentrations of AST and DEA in beagle dog and cynomolgus monkey plasma with simple preparation method and short retention time. Prior to HPLC analyses, the plasma samples were extracted with simple liquid-liquid extraction method. The isocratic mobile phase was 0.025% trifluoroacetic acid (TFA dissolved in acetonitrile) and 20 mM ammonium acetate (94:6) at a flow rate of 0.25 mL/min and diphenhydramine used as internal standard. In MS/MS analyses, precursor ions of the analytes were optimized as protonated molecular ions: [M+H](+). The lower limit of quantification of astemizole was 2.5 ng/mL in both species and desmethyl astemizole were 7.5 ng/mL and 10 ng/mL in dog and monkey plasma, respectively. The accuracy, precision, and stability of the method were in accordance with FDA guidelines for the validation of bioanalytical methods. Finally this validated method was successfully applied to a pharmacokinetic study in dogs and monkeys after oral administration of 10 mg/kg AST. Copyright © 2015 Elsevier B.V. All rights reserved.

Optimizing a neutron-beam focusing device for the direct geometry time-of-flight spectrometer TOFTOF at the FRM II reactor source

DEFF Research Database (Denmark)

Rasmussen, N. G.; Simeoni, G. G.; Lefmann, K.

2016-01-01

A dedicated beam-focusing device has been designed for the direct geometry thermal-cold neutron time-of-flight spectrometer TOFTOF at the neutron facility FRM II (Garching, Germany). The prototype, based on the compressed Archimedes' mirror concept, benefits from the adaptive-optics technology (a...... than 3.5 would have only marginal influence on the optimal behaviour, whereas comparable spectrometers could take advantage of longer focusing segments, with particular impact for the thermal region of the neutron spectrum....

SPME GC/MS determination of organochlorine pesticides in water samples

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Yerbolat Sailaukhanuly

2013-05-01

Full Text Available Headspace solid phase microextraction (HS-SPME in combination with gas chromatography and mass-spectrometry (GC/MS was studied for analysis of water samples. The organochlorine pesticides (OCPs, p,p'-DDT, p,p'-DDD, and p,p'-DDE were collected and analyzed by GC/MS. To select of effective fiber coatings four types of SPME fibers were examined and compared. The parameters effecting the efficiency of HS-SPME such as extraction and pre-incubation time and extraction temperature, effect of solvent nature, ionic strength were studied to obtain optimal parameters. The method was developed using spiked water samples in a concentration range  10 - 500 ng/L. The calibration curve was linear over the studied concentration range with r≥0.9925. The detection limits varied from 1.57 to 2.08 ng/L. An authentic water samples from contaminated lake with OCPs were analyzed by developed method.

Simultaneous Quantification of Free Cholesterol, Cholesteryl Esters, and Triglycerides without Ester Hydrolysis by UHPLC Separation and In-Source Collision Induced Dissociation Coupled MS/MS

Science.gov (United States)

Gardner, Michael S.; McWilliams, Lisa G.; Jones, Jeffrey I.; Kuklenyik, Zsuzsanna; Pirkle, James L.; Barr, John R.

2017-08-01

We demonstrate the application of in-source nitrogen collision-induced dissociation (CID) that eliminates the need for ester hydrolysis before simultaneous analysis of esterified cholesterol (EC) and triglycerides (TG) along with free cholesterol (FC) from human serum, using normal phase liquid chromatography (LC) coupled to atmospheric pressure chemical ionization (APCI) tandem mass spectrometry (MS/MS). The analysis requires only 50 μL of 1:100 dilute serum with a high-throughput, precipitation/evaporation/extraction protocol in one pot. Known representative mixtures of EC and TG species were used as calibrators with stable isotope labeled analogs as internal standards. The APCI MS source was operated with nitrogen source gas. Reproducible in-source CID was achieved with the use of optimal cone voltage (declustering potential), generating FC, EC, and TG lipid class-specific precursor fragment ions for multiple reaction monitoring (MRM). Using a representative mixture of purified FC, CE, and TG species as calibrators, the method accuracy was assessed with analysis of five inter-laboratory standardization materials, showing -10% bias for Total-C and -3% for Total-TG. Repeated duplicate analysis of a quality control pool showed intra-day and inter-day variation of 5% and 5.8% for FC, 5.2% and 8.5% for Total-C, and 4.1% and 7.7% for Total-TG. The applicability of the method was demonstrated on 32 serum samples and corresponding lipoprotein sub-fractions collected from normolipidemic, hypercholesterolemic, hypertriglyceridemic, and hyperlipidemic donors. The results show that in-source CID coupled with isotope dilution UHPLC-MS/MS is a viable high precision approach for translational research studies where samples are substantially diluted or the amounts of archived samples are limited. [Figure not available: see fulltext.

HPLC-RID-DAD-MS analysis of 18F-Fluorodeoxyglucose

International Nuclear Information System (INIS)

Macasek, F.; Buriova, E.; Bruder, P.

2001-01-01

Objective of new method of FDG analysis development is to replace existing tests by more complex assay. In this work, a liquid chromatography/refractive index detector/diode array detector/mass spectrometric detector combination (HPLC/RID/DAD/MSD) was used for development of a complex routine technique. Optimization of the HPLC/MS analysis was performed investigating MSD analytical signal as a function of various eluent composition. HPLC-RID-DAD-MSD analysis has potentiality of a complex quality control of radiopharmaceuticals, FDG in particular, providing information about: isotope composition; chemical composition; biochemical composition; radiation stability; pharmacodynamics. (author)

A comparison between DART-MS and DSA-MS in the forensic analysis of writing inks.

Science.gov (United States)

Drury, Nicholas; Ramotowski, Robert; Moini, Mehdi

2018-05-23

Ambient ionization mass spectrometry is gaining momentum in forensic science laboratories because of its high speed of analysis, minimal sample preparation, and information-rich results. One such application of ambient ionization methodology includes the analysis of writing inks from questioned documents where colorants of interest may not be soluble in common solvents, rendering thin layer chromatography (TLC) and separation-mass spectrometry methods such as LC/MS (-MS) impractical. Ambient ionization mass spectrometry uses a variety of ionization techniques such as penning ionization in Direct Analysis in Real Time (DART), and atmospheric pressure chemical ionization in Direct Sample Analysis (DSA), and electrospray ionization in Desorption Electrospray Ionization (DESI). In this manuscript, two of the commonly used ambient ionization techniques are compared: Perkin Elmer DSA-MS and IonSense DART in conjunction with a JEOL AccuTOF MS. Both technologies were equally successful in analyzing writing inks and produced similar spectra. DSA-MS produced less background signal likely because of its closed source configuration; however, the open source configuration of DART-MS provided more flexibility for sample positioning for optimum sensitivity and thereby allowing smaller piece of paper containing writing ink to be analyzed. Under these conditions, the minimum sample required for DART-MS was 1mm strokes of ink on paper, whereas DSA-MS required a minimum of 3mm. Moreover, both techniques showed comparable repeatability. Evaluation of the analytical figures of merit, including sensitivity, linear dynamic range, and repeatability, for DSA-MS and DART-MS analysis is provided. To the forensic context of the technique, DART-MS was applied to the analysis of United States Secret Service ink samples directly on a sampling mesh, and the results were compared with DSA-MS of the same inks on paper. Unlike analysis using separation mass spectrometry, which requires sample

Natural isotope correction of MS/MS measurements for metabolomics and (13)C fluxomics.

Science.gov (United States)

Niedenführ, Sebastian; ten Pierick, Angela; van Dam, Patricia T N; Suarez-Mendez, Camilo A; Nöh, Katharina; Wahl, S Aljoscha

2016-05-01

Fluxomics and metabolomics are crucial tools for metabolic engineering and biomedical analysis to determine the in vivo cellular state. Especially, the application of (13)C isotopes allows comprehensive insights into the functional operation of cellular metabolism. Compared to single MS, tandem mass spectrometry (MS/MS) provides more detailed and accurate measurements of the metabolite enrichment patterns (tandem mass isotopomers), increasing the accuracy of metabolite concentration measurements and metabolic flux estimation. MS-type data from isotope labeling experiments is biased by naturally occurring stable isotopes (C, H, N, O, etc.). In particular, GC-MS(/MS) requires derivatization for the usually non-volatile intracellular metabolites introducing additional natural isotopes leading to measurements that do not directly represent the carbon labeling distribution. To make full use of LC- and GC-MS/MS mass isotopomer measurements, the influence of natural isotopes has to be eliminated (corrected). Our correction approach is analyzed for the two most common applications; (13)C fluxomics and isotope dilution mass spectrometry (IDMS) based metabolomics. Natural isotopes can have an impact on the calculated flux distribution which strongly depends on the substrate labeling and the actual flux distribution. Second, we show that in IDMS based metabolomics natural isotopes lead to underestimated concentrations that can and should be corrected with a nonlinear calibration. Our simulations indicate that the correction for natural abundance in isotope based fluxomics and quantitative metabolomics is essential for correct data interpretation. © 2015 Wiley Periodicals, Inc.

Equilibrium and kinetic studies of Pb(II, Cd(II and Zn(II sorption by Lagenaria vulgaris shell

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Mitić-Stojanović Dragana-Linda

2012-01-01

Full Text Available The sorption of lead, cadmium and zinc ions from aqueous solution by Lagenaria vulgaris shell biosorbent (LVB in batch system was investigated. The effect of relevant parameters such as contact time, biosorbent dosage and initial metal ions concentration was evaluated. The Pb(II, Cd(II and Zn(II sorption equilibrium (when 98% of initial metal ions were sorbed was attained within 15, 20 and 25 min, respectively. The pseudo first, pseudo-second order, Chrastil’s and intra-particle diffusion models were used to describe the kinetic data. The experimental data fitted the pseudo-second order kinetic model and intra-particle diffusion model. Removal efficiency of lead(II, cadmium(II and zinc(II ions rapidly increased with increasing biosorbent dose from 0.5 to 8.0 g dm-3. Optimal biosorbent dose was set to 4.0 g dm-3. An increase in the initial metal concentration increases the sorption capacity. The sorption data of investigated metal ions are fitted to Langmuir, Freundlich and Temkin isotherm models. Langmuir model best fitted the equilibrium data (r2 > 0.99. Maximal sorption capacities of LVB for Pb(II, Cd(II and Zn(II at 25.0±0.5°C were 0.130, 0.103 and 0.098 mM g-1, respectively. The desorption experiments showed that the LVB could be reused for six cycles with a minimum loss of the initial sorption capacity.

The CAREQOL-MS was a useful instrument to measure caregiver quality of life in multiple sclerosis.

Science.gov (United States)

Benito-León, Julián; Rivera-Navarro, Jesús; Guerrero, Angel Luis; de Las Heras, Virginia; Balseiro, José; Rodríguez, Elena; Belló, Mireia; Martínez-Martín, Pablo

2011-06-01

To develop and test the first specific instrument for assessing caregiver health-related quality of life (HRQOL) in multiple sclerosis (MS) (CAREQOL-MS). Questionnaire items were derived from a literature review and the views of patients, caregivers, and experts. Instrument was reduced after the analyses of caregivers' interviews and experts' opinions. CAREQOL-MS psychometric properties were assessed in 276 MS caregivers. The final version consisted of 24 items (five subscales) and was free of floor or ceiling effects. For subscales, the Cronbach's alpha coefficient ranged from 0.75 to 0.90. The item-total correlation was 0.62-0.74 for subscale I (physical burden/global health); 0.56-0.74 for subscale II (social impact); 0.52-0.62 for subscale III (emotional impact), and 0.58-0.65 for subscale IV (need of help); subscale V (emotional reactions) had only two items. The intraclass correlation coefficient (0.96 for the total score; 0.75-0.95 for subscales) suggested satisfactory reproducibility. Association was close between CAREQOL-MS subscales and the Zarit burden interview and moderate with short form 36 mental/physical components. CAREQOL-MS subscales scores significantly increased (worse HRQOL) with increasing caregivers' age and Expanded Disability Status Scale. The standard error of the measurement ranged from 0.91 to 2.43 for subscales. Our results provided initial evidence of the usefulness and satisfactory psychometric properties of the CAREQOL-MS. Copyright © 2011 Elsevier Inc. All rights reserved.

Mono-N-acyl-2,6-diaminopimelic acid derivatives: analysis by electromigration and spectroscopic methods and examination of enzyme inhibitory activity.

Science.gov (United States)

Hlaváček, Jan; Vítovcová, Miloslava; Sázelová, Petra; Pícha, Jan; Vaněk, Václav; Buděšínský, Miloš; Jiráček, Jiří; Gillner, Danuta M; Holz, Richard C; Mikšík, Ivan; Kašička, Václav

2014-12-15

Thirteen mono-N-acyl derivatives of 2,6-diaminopimelic acid (DAP)-new potential inhibitors of the dapE-encoded N-succinyl-l,l-diaminopimelic acid desuccinylase (DapE; EC 3.5.1.18)-were analyzed and characterized by infrared (IR) and nuclear magnetic resonance (NMR) spectroscopies and two capillary electromigration methods: capillary zone electrophoresis (CZE) and micellar electrokinetic chromatography (MEKC). Structural features of DAP derivatives were characterized by IR and NMR spectroscopies, whereas CZE and MEKC were applied to evaluate their purity and to investigate their electromigration properties. Effective electrophoretic mobilities of these compounds were determined by CZE in acidic and alkaline background electrolytes (BGEs) and by MEKC in acidic and alkaline BGEs containing a pseudostationary phase of anionic detergent sodium dodecyl sulfate (SDS) or cationic detergent cetyltrimethylammonium bromide (CTAB). The best separation of DAP derivatives, including diastereomers of some of them, was achieved by MEKC in an acidic BGE (500 mM acetic acid [pH 2.54] and 60mM SDS). All DAP derivatives were examined for their ability to inhibit catalytic activity of DapE from Haemophilus influenzae (HiDapE) and ArgE from Escherichia coli (EcArgE). None of these DAP derivatives worked as an effective inhibitor of HiDapE, but one derivative-N-fumaryl, Me-ester-DAP-was found to be a moderate inhibitor of EcArgE, thereby providing a promising lead structure for further studies on ArgE inhibitors. Copyright © 2014 Elsevier Inc. All rights reserved.

Development and Validation of an LC-MS/MS Method and Comparison with a GC-MS Method to Measure Phenytoin in Human Brain Dialysate, Blood, and Saliva

Directory of Open Access Journals (Sweden)

Raphael Hösli

2018-01-01

Full Text Available Phenytoin (PHT is one of the most often used critical dose drugs, where insufficient or excessive dosing can have severe consequences such as seizures or toxicity. Thus, the monitoring and precise measuring of PHT concentrations in patients is crucial. This study develops and validates an LC-MS/MS method for the measurement of phenytoin concentrations in different body compartments (i.e., human brain dialysate, blood, and saliva and compares it with a formerly developed GC-MS method that measures PHT in the same biological matrices. The two methods are evaluated and compared based on their analytical performance, appropriateness to analyze human biological samples, including corresponding extraction and cleanup procedures, and their validation according to ISO 17025/FDA Guidance for Industry. The LC-MS/MS method showed a higher performance compared with the GC-MS method. The LC-MS/MS was more sensitive, needed a smaller sample volume (25 µL and less chemicals, was less time consuming (cleaning up, sample preparation, and analysis, and resulted in a better LOD ( 0.995 for all tested matrices (blood, saliva, and dialysate. For larger sample numbers as in pharmacokinetic/pharmacodynamic studies and for bedside as well as routine analyses, the LC-MS/MS method offers significant advantages over the GC-MS method.

Structure Annotation and Quantification of Wheat Seed Oxidized Lipids by High-Resolution LC-MS/MS.

Science.gov (United States)

Riewe, David; Wiebach, Janine; Altmann, Thomas

2017-10-01

Lipid oxidation is a process ubiquitous in life, but the direct and comprehensive analysis of oxidized lipids has been limited by available analytical methods. We applied high-resolution liquid chromatography-mass spectrometry (LC-MS) and tandem mass spectrometry (MS/MS) to quantify oxidized lipids (glycerides, fatty acids, phospholipids, lysophospholipids, and galactolipids) and implemented a platform-independent high-throughput-amenable analysis pipeline for the high-confidence annotation and acyl composition analysis of oxidized lipids. Lipid contents of 90 different naturally aged wheat ( Triticum aestivum ) seed stocks were quantified in an untargeted high-resolution LC-MS experiment, resulting in 18,556 quantitative mass-to-charge ratio features. In a posthoc liquid chromatography-tandem mass spectrometry experiment, high-resolution MS/MS spectra (5 mD accuracy) were recorded for 8,957 out of 12,080 putatively monoisotopic features of the LC-MS data set. A total of 353 nonoxidized and 559 oxidized lipids with up to four additional oxygen atoms were annotated based on the accurate mass recordings (1.5 ppm tolerance) of the LC-MS data set and filtering procedures. MS/MS spectra available for 828 of these annotations were analyzed by translating experimentally known fragmentation rules of lipids into the fragmentation of oxidized lipids. This led to the identification of 259 nonoxidized and 365 oxidized lipids by both accurate mass and MS/MS spectra and to the determination of acyl compositions for 221 nonoxidized and 295 oxidized lipids. Analysis of 15-year aged wheat seeds revealed increased lipid oxidation and hydrolysis in seeds stored in ambient versus cold conditions. © 2017 The author(s). All Rights Reserved.

Genetic characterization of Toxoplasma gondii isolates from Portugal, Austria and Israel reveals higher genetic variability within the type II lineage.

Science.gov (United States)

Verma, S K; Ajzenberg, D; Rivera-Sanchez, A; Su, C; Dubey, J P

2015-06-01

This study compared genetic diversity of Toxoplasma gondii isolates from Portugal, Austria and Israel. For this, we genotyped 90 T. gondii isolates (16 from Portugal, 67 from Austria and 7 from Israel) using 10 nested PCR-restriction length polymorphism (RFLP) genetic markers and 15 microsatellite (MS) markers. By PCR-RFLP typing, 7 isolates from Portugal chickens were identified as type II (ToxoDB #1 or #3), 4 were type III (ToxoDB #2) and the remaining 4 isolates have unique genotype pattern were designated as ToxoDB #254. One mouse virulent isolate from a bovine fetus (Bos taurus) in Portugal was type I (ToxoDB #10) at all loci and designated as TgCowPr1. All 67 isolates from Austria and 7 from Israel were type II (ToxoDB #1 or #3). By MS typing, many additional genetic variations were revealed among the type II and type III isolates. Phylogenetic analysis showed that isolates from the same geographical locations tend to cluster together, and there is little overlapping of genotypes among different locations. This study demonstrated that the MS markers can provide higher discriminatory power to reveal association of genotypes with geographical locations. Future studies of the type II strains in Europe by these MS markers will be useful to reveal transmission patterns of the parasite.

Relapsing-Remitting MS (RRMS)

Medline Plus

Full Text Available ... and problems with cognition (learning and memory or information processing). People with progressive forms of MS are more likely to experience gradually worsening problems with walking and mobility, along with whatever other symptoms they may have. Diagnosing ... MS Society is Here to Help Need More Information? We Are Here Our MS Navigators help identify ...

Rapid determination of natural and synthetic hormones in biosolids and poultry manure by isotope dilution GC-MS/MS.

Science.gov (United States)

Albero, Beatriz; Sánchez-Brunete, Consuelo; Miguel, Esther; Aznar, Ramón; Tadeo, José L

2014-04-01

The release of hormones into the environment due to land application of biosolids and manure is a cause of concern for their potential impacts. This paper presents the development of a rapid and sensitive method, based on extraction, for the analysis of 13 hormones in biosolids and poultry manure. A simultaneous derivatization of hydroxyl and ketone groups was carried out for the determination of hormones by GC–MS/MS. The method was validated in three matrices (sewage sludge, manure, and broiler litter). Recoveries from spiked samples at three concentration levels (50, 25, and 10 ng/g) ranged from 76 to 124% with relative SDs ≤ 16%. Method detection limits for the three matrices were in the range of 0.5–3.0 ng/g dry weight. The optimized method was applied to biosolid and poultry manure samples collected in Spain. Only seven of the 13 studied hormones were detected in the different samples. trans-Androsterone was detected at high levels (up to 3.1 μg/g in biosolid samples). Estrone and estradiol were the two hormones detected at higher levels in layer manure, whereas estrone and 4-androstene-3,17-dione presented the highest levels in broiler litter.

Batch removal and optimization of Cu(II) ions from aqueous solution by biosorption on to native and pretreated mangifera indica seeds

International Nuclear Information System (INIS)

Noreen, A.; Ali, G.; Jabeen, M.

2011-01-01

Biosorption is a process that utilizes biomass to sequester toxic heavy metals and is particularly useful for the removal of contaminants from industrial effluents. Present study involved batch experiments for the sorption of Cu(II) onto Mangifera indica seeds kernel particles in order to optimize the biosorbent dose, agitation rate, pH, contact time and initial metal ion concentration. The effect of citric acid pretreatment was also studied. Maximum uptake was observed at pH 5, biosorbent dose 0.5 g and agitation rate 150 rpm. A direct correlation was found to exist between adsorbed Cu(II) ion concentration and initial metal concentration upto a certain level then it reached a saturation value at about 250 mg/L. Biosorption equilibrium was established by 60 min. The maximum metal uptake capacity was 13.2 mg/g at optimized conditions. The uptake capacity of the biomass was increased by chemical pretreatment with citric acid (15.2 mg/g) when compared with the raw biomass (13.2 mg/g). Equilibrium data was fitted to Freundlich and Langmuir isotherm equations and the data was found to well represented by Langmuir isotherm equation with r/sup 2/ = 0.9981 and q/sub max/ = 17.939 mg/g for raw biomass and with r/sup 2/ = 0.9984 and qmax 18.57 mg/g for modified biomass. (author)

Loaded Gelled Bipropellants for Optimized Performance, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The focus of this program is the development and validation of formulations, and development methodologies, for optimizing high-performance particulate-loaded...

Apolipoprotein C-II Is a Potential Serum Biomarker as a Prognostic Factor of Locally Advanced Cervical Cancer After Chemoradiation Therapy

International Nuclear Information System (INIS)

Harima, Yoko; Ikeda, Koshi; Utsunomiya, Keita; Komemushi, Atsushi; Kanno, Shohei; Shiga, Toshiko; Tanigawa, Noboru

2013-01-01

Purpose: To determine pretreatment serum protein levels for generally applicable measurement to predict chemoradiation treatment outcomes in patients with locally advanced squamous cell cervical carcinoma (CC). Methods and Materials: In a screening study, measurements were conducted twice. At first, 6 serum samples from CC patients (3 with no evidence of disease [NED] and 3 with cancer-caused death [CD]) and 2 from healthy controls were tested. Next, 12 serum samples from different CC patients (8 NED, 4 CD) and 4 from healthy controls were examined. Subsequently, 28 different CC patients (18 NED, 10 CD) and 9 controls were analyzed in the validation study. Protein chips were treated with the sample sera, and the serum protein pattern was detected by surface-enhanced laser desorption and ionization–time-of-flight mass spectrometry (SELDI-TOF MS). Then, single MS-based peptide mass fingerprinting (PMF) and tandem MS (MS/MS)-based peptide/protein identification methods, were used to identify protein corresponding to the detected peak. And then, turbidimetric assay was used to measure the levels of a protein that indicated the best match with this peptide peak. Results: The same peak 8918 m/z was identified in both screening studies. Neither the screening study nor the validation study had significant differences in the appearance of this peak in the controls and NED. However, the intensity of the peak in CD was significantly lower than that of controls and NED in both pilot studies (P=.02, P=.04) and validation study (P=.01, P=.001). The protein indicated the best match with this peptide peak at 8918 m/z was identified as apolipoprotein C-II (ApoC-II) using PMF and MS/MS methods. Turbidimetric assay showed that the mean serum levels of ApoC-II tended to decrease in CD group when compared with NED group (P=.078). Conclusion: ApoC-II could be used as a biomarker for detection in predicting and estimating the radiation treatment outcome of patients with CC

Apolipoprotein C-II Is a Potential Serum Biomarker as a Prognostic Factor of Locally Advanced Cervical Cancer After Chemoradiation Therapy

Energy Technology Data Exchange (ETDEWEB)

Harima, Yoko, E-mail: harima@takii.kmu.ac.jp [Department of Radiology, Takii Hospital, Kansai Medical University, Moriguchi, Osaka (Japan); Ikeda, Koshi; Utsunomiya, Keita; Komemushi, Atsushi; Kanno, Shohei; Shiga, Toshiko [Department of Radiology, Takii Hospital, Kansai Medical University, Moriguchi, Osaka (Japan); Tanigawa, Noboru [Department of Radiology, Hirakata Hospital, Kansai Medical University, Hirakata, Osaka (Japan)

2013-12-01

Purpose: To determine pretreatment serum protein levels for generally applicable measurement to predict chemoradiation treatment outcomes in patients with locally advanced squamous cell cervical carcinoma (CC). Methods and Materials: In a screening study, measurements were conducted twice. At first, 6 serum samples from CC patients (3 with no evidence of disease [NED] and 3 with cancer-caused death [CD]) and 2 from healthy controls were tested. Next, 12 serum samples from different CC patients (8 NED, 4 CD) and 4 from healthy controls were examined. Subsequently, 28 different CC patients (18 NED, 10 CD) and 9 controls were analyzed in the validation study. Protein chips were treated with the sample sera, and the serum protein pattern was detected by surface-enhanced laser desorption and ionization–time-of-flight mass spectrometry (SELDI-TOF MS). Then, single MS-based peptide mass fingerprinting (PMF) and tandem MS (MS/MS)-based peptide/protein identification methods, were used to identify protein corresponding to the detected peak. And then, turbidimetric assay was used to measure the levels of a protein that indicated the best match with this peptide peak. Results: The same peak 8918 m/z was identified in both screening studies. Neither the screening study nor the validation study had significant differences in the appearance of this peak in the controls and NED. However, the intensity of the peak in CD was significantly lower than that of controls and NED in both pilot studies (P=.02, P=.04) and validation study (P=.01, P=.001). The protein indicated the best match with this peptide peak at 8918 m/z was identified as apolipoprotein C-II (ApoC-II) using PMF and MS/MS methods. Turbidimetric assay showed that the mean serum levels of ApoC-II tended to decrease in CD group when compared with NED group (P=.078). Conclusion: ApoC-II could be used as a biomarker for detection in predicting and estimating the radiation treatment outcome of patients with CC.

BINARY PARTICLE SWARM OPTIMIZATION APPROACH FOR RANDOM GENERATION OUTAGE MAINTENANCE SCHEDULING

Directory of Open Access Journals (Sweden)

K. Suresh

2013-01-01

Full Text Available This paper presents a methodology for maintenance scheduling (MS of generators using binary particle swarm optimization (BPSO based probabilistic approach. The objective of this paper is to reduce the loss of load probability (LOLP for a power system. The capacity outage probability table (COPT is the initial step in creating maintenance schedule using the probabilistic levelized risk method. This paper proposes BPSO method which is used to construct the COPT. In order to mitigate the effects of probabilistic levelized risk method, BPSO based probabilistic levelized risk method is embarked on a MS problem. In order to validate the effectiveness of the proposed algorithm, case study results for simple five unit system can accomplish a significant levelization in the reliability indices that make possible to evaluate system generation system adequacy in the MS horizon of the power system. The proposed method shows better performance compared with other optimization methods and conventional method with improved search performance.

Discrimination of Aspergillus lentulus from Aspergillus fumigatus by Raman spectroscopy and MALDI-TOF MS.

Science.gov (United States)

Verwer, P E B; van Leeuwen, W B; Girard, V; Monnin, V; van Belkum, A; Staab, J F; Verbrugh, H A; Bakker-Woudenberg, I A J M; van de Sande, W W J

2014-02-01

In 2005, a new sibling species of Aspergillus fumigatus was discovered: Aspergillus lentulus. Both species can cause invasive fungal disease in immune-compromised patients. The species are morphologically very similar. Current techniques for identification are PCR-based or morphology-based. These techniques are labour-intense and not sufficiently discriminatory. Since A. lentulus is less susceptible to several antifungal agents, it is important to correctly identify the causative infectious agent in order to optimize antifungal therapy. In this study we determined whether Raman spectroscopy and/or MALDI-TOF MS were able to differentiate between A. lentulus and A. fumigatus. For 16 isolates of A. lentulus and 16 isolates of A. fumigatus, Raman spectra and peptide profiles were obtained using the Spectracell and MALDI-TOF MS (VITEK MS RUO, bioMérieux) respectively. In order to obtain reliable Raman spectra for A. fumigatus and A. lentulus, the culture medium needed to be adjusted to obtain colourless conidia. Only Raman spectra obtained from colourless conidia were reproducible and correctly identified 25 out of 32 (78 %) of the Aspergillus strains. For VITEK MS RUO, no medium adjustments were necessary. Pigmented conidia resulted in reproducible peptide profiles as well in this case. VITEK MS RUO correctly identified 100 % of the Aspergillus isolates, within a timeframe of approximately 54 h including culture. Of the two techniques studied here, VITEK MS RUO was superior to Raman spectroscopy in the discrimination of A. lentulus from A. fumigatus. VITEK MS RUO seems to be a successful technique in the daily identification of Aspergillus spp. within a limited timeframe.

Simplifying the Preparation of Pollen Grains for MALDI-TOF MS Classification

Directory of Open Access Journals (Sweden)

Franziska Lauer

2017-03-01

Full Text Available Matrix-assisted laser desorption ionization time of flight mass spectrometry (MALDI-TOF MS is a well-implemented analytical technique for the investigation of complex biological samples. In MS, the sample preparation strategy is decisive for the success of the measurements. Here, sample preparation processes and target materials for the investigation of different pollen grains are compared. A reduced and optimized sample preparation process prior to MALDI-TOF measurement is presented using conductive carbon tape as target. The application of conductive tape yields in enhanced absolute signal intensities and mass spectral pattern information, which leads to a clear separation in subsequent pattern analysis. The results will be used to improve the taxonomic differentiation and identification, and might be useful for the development of a simple routine method to identify pollen based on mass spectrometry.

Adsorption dynamics and equilibrium studies of Zn (II) onto chitosan

Indian Academy of Sciences (India)

Unknown

Adsorption dynamics and equilibrium studies of Zn (II) onto chitosan. G KARTHIKEYAN*, K ANBALAGAN and N MUTHULAKSHMI ANDAL. Department of Chemistry, Gandhigram Rural Institute – Deemed University, Gandhigram 624 302, India e-mail: drg_karthikeyan@rediffmail.com. MS received 3 June 2003; revised 12 ...

Use of the HRICP-MS technique for the evaluation of boron isotopes in Eucalitpus plants; Uso da tecnica HRICP-MS na avaliacao dos isotopos de boro em eucalipto

Energy Technology Data Exchange (ETDEWEB)

Mattiello, Edson Marcio; Ruiz, Hugo Alberto; Silva, Ivo Ribeiro da, E-mail: mattiello@ufv.b [Universidade Federal de Vicosa (UFV), MG (Brazil). Dept. de Solos; Sarkis, Jorge Eduardo de Souza [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)

2011-07-01

The {sup 10}B isotope tracer technique is essential to study the B mobility in plants. Factors that can influence the quality of measured B isotope ratios were optimized experimentally using High Resolution Inductively Coupled Plasma Mass Spectrometry (HRICP-MS). An isotopically certified standard (NIST SRM-951) was used. The best combination was obtained using a resolution of 400, a RF power of 1250 W, followed by 15 measurements over a 10-s integration period each (15*10). Utilizing this approach it was possible to obtain a precision of 0.3 % in standard material and 2z % in the experimental samples. The results show the importance of establishing optimized work conditions before carrying out the analytical series. (author)

A New Hybrid Whale Optimizer Algorithm with Mean Strategy of Grey Wolf Optimizer for Global Optimization

Directory of Open Access Journals (Sweden)

Narinder Singh

2018-03-01

Full Text Available The quest for an efficient nature-inspired optimization technique has continued over the last few decades. In this paper, a hybrid nature-inspired optimization technique has been proposed. The hybrid algorithm has been constructed using Mean Grey Wolf Optimizer (MGWO and Whale Optimizer Algorithm (WOA. We have utilized the spiral equation of Whale Optimizer Algorithm for two procedures in the Hybrid Approach GWO (HAGWO algorithm: (i firstly, we used the spiral equation in Grey Wolf Optimizer algorithm for balance between the exploitation and the exploration process in the new hybrid approach; and (ii secondly, we also applied this equation in the whole population in order to refrain from the premature convergence and trapping in local minima. The feasibility and effectiveness of the hybrid algorithm have been tested by solving some standard benchmarks, XOR, Baloon, Iris, Breast Cancer, Welded Beam Design, Pressure Vessel Design problems and comparing the results with those obtained through other metaheuristics. The solutions prove that the newly existing hybrid variant has higher stronger stability, faster convergence rate and computational accuracy than other nature-inspired metaheuristics on the maximum number of problems and can successfully resolve the function of constrained nonlinear optimization in reality.

Development and application of a quantitative method based on LC-QqQ MS/MS for determination of steviol glycosides in Stevia leaves.

Science.gov (United States)

Molina-Calle, M; Sánchez de Medina, V; Delgado de la Torre, M P; Priego-Capote, F; Luque de Castro, M D

2016-07-01

Stevia is a currently well-known plant thanks to the presence of steviol glycosides, which are considered as sweeteners obtained from a natural source. In this research, a method based on LC-MS/MS by using a triple quadrupole detector was developed for quantitation of 8 steviol glycosides in extracts from Stevia leaves. The ionization and fragmentation parameters for selected reaction monitoring were optimized. Detection and quantitation limits ranging from 0.1 to 0.5ng/mL and from 0.5 to 1ng/mL, respectively, were achieved: the lowest attained so far. The steviol glycosides were quantified in extracts from leaves of seven varieties of Stevia cultivated in laboratory, greenhouse and field. Plants cultivated in field presented higher concentration of steviol glycosides than those cultivated in greenhouse. Thus, the way of cultivation clearly influences the concentration of these compounds. The inclusion of branches together with leaves as raw material was also evaluated, showing that this inclusion modifies, either positively or negatively, the concentration of steviol glycosides. Copyright © 2016 Elsevier B.V. All rights reserved.

Optimized ventilation-on-demand (VOD)

Energy Technology Data Exchange (ETDEWEB)

Masse, M. [Simsmart Technologies Inc., Brossard, PQ (Canada); Cervinka, A. [Newtrax Technologies Inc., Montreal, PQ (Canada)

2008-07-01

This presentation described how the combination of 2 innovative technologies can help optimize mine ventilation. Newtrax Technologies has developed a self-contained battery-powered wireless electronic system designed to operate in harsh industrial environments, including underground mines. Simsmart Technologies has created an advanced process and control simulation based design tool used in industrial applications, including mine ventilation systems. This presentation described the system components and how they work. These included the wireless mesh network designed for dynamic diesel machinery tracking and operating status monitoring; the real-time ventilation model and fan speed optimizer; the OPC server for information interchange; the OPC linkage to existing control infrastructure; a human machine interface that provide data archiving capability; live MS-Excel to interrogate the simulation, controls and optimizer; and, the battery-powered network mesh that provides SCADA functionality to route optimized setpoints. Details of the user interface were also provided. 1 tab., 20 figs.

Equilibrium modeling of mono and binary sorption of Cu(II and Zn(II onto chitosan gel beads

Directory of Open Access Journals (Sweden)

Nastaj Józef

2016-12-01

Full Text Available The objective of the work are in-depth experimental studies of Cu(II and Zn(II ion removal on chitosan gel beads from both one- and two-component water solutions at the temperature of 303 K. The optimal process conditions such as: pH value, dose of sorbent and contact time were determined. Based on the optimal process conditions, equilibrium and kinetic studies were carried out. The maximum sorption capacities equaled: 191.25 mg/g and 142.88 mg/g for Cu(II and Zn(II ions respectively, when the sorbent dose was 10 g/L and the pH of a solution was 5.0 for both heavy metal ions. One-component sorption equilibrium data were successfully presented for six of the most useful three-parameter equilibrium models: Langmuir-Freundlich, Redlich-Peterson, Sips, Koble-Corrigan, Hill and Toth. Extended forms of Langmuir-Freundlich, Koble-Corrigan and Sips models were also well fitted to the two-component equilibrium data obtained for different ratios of concentrations of Cu(II and Zn(II ions (1:1, 1:2, 2:1. Experimental sorption data were described by two kinetic models of the pseudo-first and pseudo-second order. Furthermore, an attempt to explain the mechanisms of the divalent metal ion sorption process on chitosan gel beads was undertaken.

Determination of drug residues by CLAR-MS/MS in animal tissues

International Nuclear Information System (INIS)

Brenes Jimenez, Jose Eduardo

2009-01-01

Produced food of animal origin, present the possibility of occurrence of any contact with substances that have negative effects on the health of people who consume them. The use of drugs in veterinary medicine is one of the possible sources of such waste; so, the conditions for the analysis of some classes of antibiotics in animal tissues are based on the study. Costa Rica and the countries that are export destination, have regulation and programs for control before to be distributed in local markets, or post if it is received any complaint of pollution. The high resolution liquid chromatography coupled to mass spectrometers (CLAR-MS/MS) allows the analysis of analytes monitored, according to the specifications required by the legislation. The cases of two laboratories in Costa Rica are presented as the only ones who have the ability to perform the analysis of drug residues CLAR-MS/MS. (author) [es

Optimal recombination in genetic algorithms for combinatorial optimization problems: Part I

Directory of Open Access Journals (Sweden)

Eremeev Anton V.

2014-01-01

Full Text Available This paper surveys results on complexity of the optimal recombination problem (ORP, which consists in finding the best possible offspring as a result of a recombination operator in a genetic algorithm, given two parent solutions. We consider efficient reductions of the ORPs, allowing to establish polynomial solvability or NP-hardness of the ORPs, as well as direct proofs of hardness results. Part I presents the basic principles of optimal recombination with a survey of results on Boolean Linear Programming Problems. Part II (to appear in a subsequent issue is devoted to the ORPs for problems which are naturally formulated in terms of search for an optimal permutation.

Ion mobility spectrometer / mass spectrometer (IMS-MS).

Energy Technology Data Exchange (ETDEWEB)

Hunka Deborah Elaine; Austin, Daniel E.

2005-07-01

The use of Ion Mobility Spectrometry (IMS) in the Detection of Contraband Sandia researchers use ion mobility spectrometers for trace chemical detection and analysis in a variety of projects and applications. Products developed in recent years based on IMS-technology include explosives detection personnel portals, the Material Area Access (MAA) checkpoint of the future, an explosives detection vehicle portal, hand-held detection systems such as the Hound and Hound II (all 6400), micro-IMS sensors (1700), ordnance detection (2500), and Fourier Transform IMS technology (8700). The emphasis to date has been on explosives detection, but the detection of chemical agents has also been pursued (8100 and 6400). Combining Ion Mobility Spectrometry (IMS) with Mass Spectrometry (MS) is described. The IMS-MS combination overcomes several limitations present in simple IMS systems. Ion mobility alone is insufficient to identify an unknown chemical agent. Collision cross section, upon which mobility is based, is not sufficiently unique or predictable a priori to be able to make a confident peak assignment unless the compounds present are already identified. Molecular mass, on the other hand, is much more readily interpreted and related to compounds. For a given compound, the molecular mass can be determined using a pocket calculator (or in one's head) while a reasonable value of the cross-section might require hours of computation time. Thus a mass spectrum provides chemical specificity and identity not accessible in the mobility spectrum alone. In addition, several advanced mass spectrometric methods, such as tandem MS, have been extensively developed for the purpose of molecular identification. With an appropriate mass spectrometer connected to an ion mobility spectrometer, these advanced identification methods become available, providing greater characterization capability.

DNA binding and cleavage activity by a mononuclear iron(II)Schiff ...

Indian Academy of Sciences (India)

e-mail: rajarshi_chem@yahoo.co.in; bunair@clri.res.in. MS received 21 January ..... thesis, single crystal X-ray structural characterization of an iron(II) complex (1) ... of Burdwan and Council for Scientific and Industrial. Research (CSIR), New ...

Discrete Geometry Toolkit for Shape Optimization, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — Simulation-based design optimization has been steadily maturing over the past two decades, but not without its own unique and persistent challenges. The proposed...

Enhanced Multi-Objective Energy Optimization by a Signaling Method

OpenAIRE

Soares, João; Borges, Nuno; Vale, Zita; Oliveira, P.B.

2016-01-01

In this paper three metaheuristics are used to solve a smart grid multi-objective energy management problem with conflictive design: how to maximize profits and minimize carbon dioxide (CO2) emissions, and the results compared. The metaheuristics implemented are: weighted particle swarm optimization (W-PSO), multi-objective particle swarm optimization (MOPSO) and non-dominated sorting genetic algorithm II (NSGA-II). The performance of these methods with the use of multi-dimensi...

Multielement analysis of Zanthoxylum bungeanum Maxim. essential oil using ICP-MS/MS.

Science.gov (United States)

Fu, Liang; Xie, Hualin; Shi, Shuyun

2018-04-12

The concentrations of trace elements (Cr, Ni, As, Cd, Hg, and Pb) in Zanthoxylum bungeanum Maxim. essential oil (ZBMEO) were determined by inductively coupled plasma tandem mass spectrometry. The ZBMEO sample was directly analyzed after simple dilution with n-hexane. Aiming for a relatively high vapor pressure of n-hexane and its resultant loading on plasma, we used a narrow injector torch and optimized plasma radio frequency power and carrier gas flow to ensure stable operation of the plasma. An optional gas flow of 20% O 2 in Ar was added to the carrier gas to prevent the incomplete combustion of highly concentrated organic carbon in plasma and the deposition of carbon on the sampling and skimmer cone orifices. In tandem mass spectrometry mode, O 2 was added to the collision/reaction cell to eliminate the interferences. The limits of detection for Cr, Ni, As, Cd, Hg, and Pb were 2.26, 1.64, 2.02, 1.35, 1.76, and 0.97 ng L -1 , respectively. After determination of 23 ZBMEO samples from different regions in China, we found that the average concentration ranges of trace elements in the 23 ZBMEO samples were 0.72-6.02 ng g -1 , 0.09-2.87 ng g -1 , 0.21-5.84 ng g -1 , 0.16-2.15 ng g -1 , 0.13-0.92 ng g -1 , and 0.17-0.73 ng g -1 for Cr, Ni, As, Cd, Hg, and Pb, respectively. The trace elements in ZBMEO differed significantly when different extraction technologies were used. The study revealed that the contents of the toxic elements As, Cd, Hg, and Pb were extremely low, and hence they are unlikely to pose a health risk following ZBMEO ingestion. Graphical abstract The working mechanism of sample analysis by ICP-MS/MS.

A Modified GC-MS Analytical Procedure for Separation and Detection of Multiple Classes of Carbohydrates

Directory of Open Access Journals (Sweden)

Yong-Gang Xia

2018-05-01

Full Text Available A modified GC-MS analytical procedure based on trimethylsilyl-dithioacetal (TMSD derivatization has been established for a simultaneous determination of thirteen carbohydrates. Different from previous approaches, the current GC-MS method was featured by a powerful practicability for simultaneous detection of aldoses, uronic acids, ketoses, and amino sugars; simplifying GC-MS chromatograms and producing a single peak for each derivatized sugar, as well as high resolution, sensitivity, and repeatability. An additional liquid-liquid extraction from derivatization mixtures was performed not only to increase the detection sensitivity of amino sugars but also to decrease the by-products of derivatization. Contrarily, three amino sugars were detected at a very low intensity or not detected at all. The effect of time on monosaccharide- mercaptalated reaction was systematically investigated. The effect of trimethylsilylation on the formation of TMSD was also optimized. The established GC-MS based on TMSD derivatization was suitable for complex carbohydrate analysis and has been successfully applied for the detection of free carbohydrates in water extracts of Anemarrhena asphodeloides roots and determination of monosaccharides in Glossy ganoderma polysaccharides.

Simple and rapid quantification of vancomycin in serum, urine and peritoneal/pleural effusion via UHPLC-MS/MS applicable to personalized antibiotic dosing research.

Science.gov (United States)

Javorska, Lenka; Krcmova, Lenka Kujovska; Solich, Petr; Kaska, Milan

2017-08-05

Management of the therapy of life-threatening bacterial infection is extremely based on an optimal antibiotic treatment. Achieving the correct vancomycin dosage in blood and target tissues can be complicated in special situations, e.g., where large fluid sequestration and/or acute renal failure occur. A UHPLC-MS/MS method operating in electrospray (ESI) positive ion mode was applied for the determination of vancomycin in serum, urine and peritoneal/pleural effusion. Sample pretreatment was composed of dilution and simple protein precipitation where only a small volume (50μL) of serum, urine or peritoneal/pleural effusion was required. The separation of vancomycin was performed on a Meteoric Core C18 BIO column (100×4.6mm, 2.7μm) by gradient elution with 0.1% formic acid in water and acetonitrile. The total time of analysis was 4.5min. The method was found to be linear in the range of 2-60μM (or 0.5-10μM) for serum, 0.27-10μM (or 2-60μM) for peritoneal/pleural effusion and 25-300μM for urine, which was adequate for the determination of vancomycin in patient samples. The intra- and inter-day precision was below 8% RSD, and accuracy was from 89 to 104%. The UHPLC/MS-MS method offers a fast and reliable approach to determine vancomycin concentrations in three different human body fluid samples (serum, urine and peritoneal/pleural effusion) with a simple sample pretreatment that was the same for all selected specimens. This method should be applicable to large sample series in clinical (pharmacokinetic/pharmacodynamic) studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Evaluation of various QuEChERS based methods for the analysis of herbicides and other commonly used pesticides in polished rice by LC-MS/MS.

Science.gov (United States)

Pareja, Lucía; Cesio, Verónica; Heinzen, Horacio; Fernández-Alba, Amadeo R

2011-02-15

Four different extraction and clean-up protocols based on the QuEChERS method were compared for the development of an optimized sample preparation procedure for the multiresidue analysis of 16 commonly applied herbicides in rice crops using LC-QqQ/MS. Additionally the methods were evaluated for the analysis of 26 insecticides and fungicides currently used in rice crops. The methods comprise, in general, the hydratation of the sample with water followed by the extraction with acetonitrile, phase separation with the addition of different salts and finally a clean-up step with various sorbents. Matrix effects were evaluated for the 4 studied methods using LC-QqQ/MS. Additionally LC-TOF/MS was used to compare the co-extractants obtained with the four assayed methodologies. Thirty-six pesticides presented good performance with recoveries in the range 70-120% and relative standard deviations below 20% using 7.5 g of milled polished rice and the buffered acetate QuEChERS method without clean-up at both fortification levels: 10 and 300 μg kg(-1). The other six pesticides presented low recovery rates, nevertheless all these analytes could be analyzed with at least one of the other three studied procedures. Copyright © 2010. Published by Elsevier B.V.

Simultaneous determination of Cd(II) and Pb(II) by differential pulse anodic stripping voltammetry based on graphite nanofibers-Nafion composite modified bismuth film electrode.

Science.gov (United States)

Li, Dongyue; Jia, Jianbo; Wang, Jianguo

2010-12-15

A bismuth-film modified graphite nanofibers-Nafion glassy carbon electrode (BiF/GNFs-NA/GCE) was constructed for the simultaneous determination of trace Cd(II) and Pb(II). The electrochemical properties and applications of the modified electrode were studied. Operational parameters such as deposition potential, deposition time, and bismuth ion concentration were optimized for the purpose of determination of trace metal ions in 0.10 M acetate buffer solution (pH 4.5). Under optimal conditions, based on three times the standard deviation of the baseline, the limits of detection were 0.09 μg L(-1) for Cd(II) and 0.02 μg L(-1) for Pb(II) with a 10 min preconcentration. In addition, the BiF/GNFs-NA/GCE displayed good reproducibility and selectivity, making it suitable for the simultaneous determination of Cd(II) and Pb(II) in real sample such as river water and human blood samples. Copyright © 2010 Elsevier B.V. All rights reserved.

Identification of phase I and II metabolites of the new designer drug α-pyrrolidinohexiophenone (α-PHP) in human urine by liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS).

Science.gov (United States)

Paul, Michael; Bleicher, Sergej; Guber, Susanne; Ippisch, Josef; Polettini, Aldo; Schultis, Wolfgang

2015-11-01

Pyrrolidinophenones represent one emerging class of newly encountered drugs of abuse, also known as 'new psychoactive substances', with stimulating psychoactive effects. In this work, we report on the detection of the new designer drug α-pyrrolidinohexiophenone (α-PHP) and its phase I and II metabolites in a human urine sample of a drug abuser. Determination and structural elucidation of these metabolites have been achieved by liquid chromatography electrospray ionisation quadrupole time-of-flight mass spectrometry (LC-ESI-QTOF-MS). By tentative identification, the exact and approximate structures of 19 phase I metabolites and nine phase II glucuronides were elucidated. Major metabolic pathways revealed the reduction of the ß-keto moieties to their corresponding alcohols, didesalkylation of the pyrrolidine ring, hydroxylation and oxidation of the aliphatic side chain leading to n-hydroxy, aldehyde and carboxylate metabolites, and oxidation of the pyrrolidine ring to its lactam followed by ring cleavage and additional hydroxylation, reduction and oxidation steps and combinations thereof. The most abundant phase II metabolites were glucuronidated ß-keto-reduced alcohols. Besides the great number of metabolites detected in this sample, α-PHP is still one of the most abundant ions together with its ß-keto-reduced alcoholic dihydro metabolite. Monitoring of these metabolites in clinical and forensic toxicology may unambiguously prove the abuse of the new designer drug α-PHP. Copyright © 2015 John Wiley & Sons, Ltd.

Commissioning of the laboratory of Atucha II NPP. Implementation and optimization of analytical techniques, quality aspects

International Nuclear Information System (INIS)

Schoenbrod, Betina; Quispe, Benjamin; Cattaneo, Alberto; Rodriguez, Ivanna; Chocron, Mauricio; Farias, Silvia

2012-09-01

Atucha II NPP is a Pressurized Vessel Heavy Water Reactor (PVHWR) of 740 MWe designed by SIEMENSKWU. After some years of delay, this NPP is in advanced construction state, being the beginning of commercial operation expected for 2013. Nucleoelectrica Argentina (N.A.S.A.) is the company in charge of the finalization of this project and the future operation of the plant. The Comision Nacional de Energia Atomica (C.N.E.A.) is the R and D nuclear institution in the country that, among many other topics, provides technical support to the stations. The Commissioning Chemistry Division of CNAII is in charge of the commissioning of the demineralization water plant and the organization of the chemical laboratory. The water plant started operating successfully in July 2010 and is providing the plant with nuclear grade purity water. Currently, in the conventional ('cold') laboratory several activities are taking place. On one hand, analytical techniques for the future operation of the plant are being tested and optimized. On the other hand, the laboratory is participating in the cleaning and conservation of the different components of the plant, providing technical support and the necessary analysis. To define the analytical techniques for the normal operation of the plant, the parameters to be measured and their range were established in the Chemistry Manual. The necessary equipment and reagents were bought. In this work, a summary of the analytical techniques that are being implemented and optimized is presented. Common anions (chloride, sulfate, fluoride, bromide and nitrate) are analyzed by ion chromatography. Cations, mainly sodium, are determined by absorption spectrometry. A UV-Vis spectrometer is used to determine silicates, iron, ammonia, DQO, total solids, true color and turbidity. TOC measurements are performed with a TOC analyzer. To optimize the methods, several parameters are evaluated: linearity, detection and quantification limits, precision and

Dynamic changes of flavonoids in Abelmoschus manihot different organs at different growth periods by UPLC-MS/MS.

Science.gov (United States)

Pan, Xinxin; Du, Leyue; Tao, Jinhua; Jiang, Shu; Qian, Dawei; Duan, Jinao

2017-08-01

Abelmoschus manihot (Linn.) Medicus has been clinically used to treat chronic kidney disease, oral ulcers, burns, and dysmenorrhea in China for many centuries. The major pharmacologically-active components of A. manihot are flavonoids. In this study, a rapid and highly sensitive UPLC-MS/MS analysis method was established and successfully applied to the simultaneous determination of five major flavonoids (rutin, hyperoside, isoquercitrin, quercetin, and myricetin) in different parts of A. manihot harvested at ten growth periods. Under the optimized chromatographic conditions, good separation for five target components was obtained on an Acquity UPLC BEH C18 column within 18min. The total contents of the five investigated flavonoids in A. manihot roots, stems, leaves and flowers ranged from 2.86 to 123.7μg/g, 46.39 to 141.0μg/g, 929.4 to 3096μg/g, and 10,150 to 19,390μg/g, respectively, indicating that the total flavonoids in the four parts could be mainly arranged in a decreasing order as flower>leaf>stem>root. The peak of total flavonoids in flowers and leaves appeared at G8 and G9, respectively. These results will be helpful for the determination of the suitable harvest time of A. manihot and the improvement of the utility value of the disused parts. Copyright © 2017 Elsevier B.V. All rights reserved.

Metabolomic and elemental analysis of camel and bovine urine by GC-MS and ICP-MS.

Science.gov (United States)

Ahamad, Syed Rizwan; Alhaider, Abdul Qader; Raish, Mohammad; Shakeel, Faiyaz

2017-01-01

Recent studies from the author's laboratory indicated that camel urine possesses antiplatelet activity and anti-cancer activity which is not present in bovine urine. The objective of this study is to compare the volatile and elemental components of bovine and camel urine using GC-MS and ICP-MS analysis. We are interested to know the component that performs these biological activities. The freeze dried urine was dissolved in dichloromethane and then derivatization process followed by using BSTFA for GC-MS analysis. Thirty different compounds were analyzed by the derivatization process in full scan mode. For ICP-MS analysis twenty eight important elements were analyzed in both bovine and camel urine. The results of GC-MS and ICP-MS analysis showed marked difference in the urinary metabolites. GC-MS evaluation of camel urine finds a lot of products of metabolism like benzene propanoic acid derivatives, fatty acid derivatives, amino acid derivatives, sugars, prostaglandins and canavanine. Several research reports reveal the metabolomics studies on camel urine but none of them completely reported the pharmacology related metabolomics. The present data of GC-MS suggest and support the previous studies and activities related to camel urine.

Rapid adsorption of copper(II) and lead(II) by rice straw/Fe₃O₄ nanocomposite: optimization, equilibrium isotherms, and adsorption kinetics study.

Science.gov (United States)

Khandanlou, Roshanak; Ahmad, Mansor B; Fard Masoumi, Hamid Reza; Shameli, Kamyar; Basri, Mahiran; Kalantari, Katayoon

2015-01-01

Rice straw/magnetic nanocomposites (RS/Fe3O4-NCs) were prepared via co-precipitation method for removal of Pb(II) and Cu(II) from aqueous solutions. Response surface methodology (RSM) was utilized to find the optimum conditions for removal of ions. The effects of three independent variables including initial ion concentration, removal time, and adsorbent dosage were investigated on the maximum adsorption of Pb (II) and Cu (II). The optimum conditions for the adsorption of Pb(II) and Cu(II) were obtained (100 and 60 mg/L) of initial ion concentration, (41.96 and 59.35 s) of removal time and 0.13 g of adsorbent for both ions, respectively. The maximum removal efficiencies of Pb(II) and Cu(II) were obtained 96.25% and 75.54%, respectively. In the equilibrium isotherm study, the adsorption data fitted well with the Langmuir isotherm model. The adsorption kinetics was best depicted by the pseudo-second order model. Desorption experiments showed adsorbent can be reused successfully for three adsorption-desorption cycles.

Ground Processing Optimization Using Artificial Intelligence Techniques, Phase II

Data.gov (United States)

National Aeronautics and Space Administration — The ultimate goal is the automation of a large amount of KSC's planning, scheduling, and execution decision making. Phase II will result in a complete full-scale...

Application of LC–MS/MS for quantitative analysis of glucocorticoids and stimulants in biological fluids

OpenAIRE

Haneef, Jamshed; Shaharyar, Mohammad; Husain, Asif; Rashid, Mohd; Mishra, Ravinesh; Parveen, Shama; Ahmed, Niyaz; Pal, Manoj; Kumar, Deepak

2013-01-01

Liquid chromatography tandem mass chromatography (LCâMS/MS) is an important hyphenated technique for quantitative analysis of drugs in biological fluids. Because of high sensitivity and selectivity, LCâMS/MS has been used for pharmacokinetic studies, metabolites identification in the plasma and urine. This manuscript gives comprehensive analytical review, focusing on chromatographic separation approaches (column packing materials, column length and mobile phase) as well as different acquisiti...

Application of LC–MS/MS for quantitative analysis of glucocorticoids and stimulants in biological fluids

OpenAIRE

Haneef, Jamshed; Shaharyar, Mohammad; Husain, Asif; Rashid, Mohd; Mishra, Ravinesh; Parveen, Shama; Ahmed, Niyaz; Pal, Manoj; Kumar, Deepak

2013-01-01

Liquid chromatography tandem mass chromatography (LC–MS/MS) is an important hyphenated technique for quantitative analysis of drugs in biological fluids. Because of high sensitivity and selectivity, LC–MS/MS has been used for pharmacokinetic studies, metabolites identification in the plasma and urine. This manuscript gives comprehensive analytical review, focusing on chromatographic separation approaches (column packing materials, column length and mobile phase) as well as different acquisiti...

FASTRAN II - FATIGUE CRACK GROWTH STRUCTURAL ANALYSIS (IBM PC VERSION)

Science.gov (United States)

Newman, J. C.

1994-01-01

loads may be either tensile or compressive. Several standardized aircraft flight-load histories, such as TWIST, Mini-TWIST, FALSTAFF, Inverted FALSTAFF, Felix and Gaussian, are included as options. FASTRAN II also includes two other methods that will help the user input spectrum load histories. The two methods are: (1) a list of stress points, and (2) a flight-by-flight history of stress points. Examples are provided in the user manual. Developed as a research program, FASTRAN II has successfully predicted crack growth in many metallic materials under various aircraft spectrum loading. A computer program DKEFF which is a part of the FASTRAN II package was also developed to analyze crack growth rate data from laboratory specimens to obtain the effective stress-intensity factor against crack growth rate relations used in FASTRAN II. FASTRAN II is written in standard FORTRAN 77. It has been successfully compiled and implemented on Sun4 series computers running SunOS and on IBM PC compatibles running MS-DOS using the Lahey F77L FORTRAN compiler. Sample input and output data are included with the FASTRAN II package. The UNIX version requires 660K of RAM for execution. The standard distribution medium for the UNIX version (LAR-14865) is a .25 inch streaming magnetic tape cartridge in UNIX tar format. It is also available on a 3.5 inch diskette in UNIX tar format. The standard distribution medium for the MS-DOS version (LAR-14944) is a 5.25 inch 360K MS-DOS format diskette. The contents of the diskette are compressed using the PKWARE archiving tools. The utility to unarchive the files, PKUNZIP.EXE, is included. The program was developed in 1984 and revised in 1992. Sun4 and SunOS are trademarks of Sun Microsystems, Inc. IBM PC is a trademark of International Business Machines Corp. MS-DOS is a trademark of Microsoft, Inc. F77L is a trademark of the Lahey Computer Systems, Inc. UNIX is a registered trademark of AT&T Bell Laboratories. PKWARE and PKUNZIP are trademarks of PKWare

Improved LC-MS/MS method for the quantification of hepcidin-25 in clinical samples.

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Abbas, Ioana M; Hoffmann, Holger; Montes-Bayón, María; Weller, Michael G

2018-06-01

Mass spectrometry-based methods play a crucial role in the quantification of the main iron metabolism regulator hepcidin by singling out the bioactive 25-residue peptide from the other naturally occurring N-truncated isoforms (hepcidin-20, -22, -24), which seem to be inactive in iron homeostasis. However, several difficulties arise in the MS analysis of hepcidin due to the "sticky" character of the peptide and the lack of suitable standards. Here, we propose the use of amino- and fluoro-silanized autosampler vials to reduce hepcidin interaction to laboratory glassware surfaces after testing several types of vials for the preparation of stock solutions and serum samples for isotope dilution liquid chromatography-tandem mass spectrometry (ID-LC-MS/MS). Furthermore, we have investigated two sample preparation strategies and two chromatographic separation conditions with the aim of developing a LC-MS/MS method for the sensitive and reliable quantification of hepcidin-25 in serum samples. A chromatographic separation based on usual acidic mobile phases was compared with a novel approach involving the separation of hepcidin-25 with solvents at high pH containing 0.1% of ammonia. Both methods were applied to clinical samples in an intra-laboratory comparison of two LC-MS/MS methods using the same hepcidin-25 calibrators with good correlation of the results. Finally, we recommend a LC-MS/MS-based quantification method with a dynamic range of 0.5-40 μg/L for the assessment of hepcidin-25 in human serum that uses TFA-based mobile phases and silanized glass vials. Graphical abstract Structure of hepcidin-25 (Protein Data Bank, PDB ID 2KEF).

SEPARATION OF Fe (III, Cr(III, Cu(II, Ni(II, Co(II, AND Pb(II METAL IONS USING POLY(EUGENYL OXYACETIC ACID AS AN ION CARRIER BY A LIQUID MEMBRANE TRANSPORT METHOD

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La Harimu

2010-06-01

Full Text Available Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II  metal ions had been separated using poly(eugenyl oxyacetic acid as an ion carrier by bulk liquid membrane transport method. The effect of pH, polyeugenyl oxyacetic acid ion carrier concentration, nitric acid concentration in the stripping solution, transport time, and metal concentration were optimized. The result showed that the optimum condition for transport of metal ions was at pH 4 for ion Fe(III and at pH 5 for Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions. The carrier volumes were optimum with concentration of 1 x 10-3 M at 7.5 mL for Cr(III, Cu (II,  Ni(II, Co(II ions and at 8.5 mL for Fe(III and Pb(II ions. The concentration of HNO3 in stripping phase was optimum at 2 M for Fe(III and Cu(II ions, 1 M for Cr(III, Ni(II and Co(II ions, and 0.5 M for Pb(II ion. The optimum transport times were 36 h for Fe(III and Co(II ions, and 48 h for Cr(III, Cu (II, Ni(II, and Pb(II ions. The concentration of metal ions accurately transported were 2.5 x 10-4 M for Fe(III and Cr(III ions, and 1 M for Cu (II, Ni(II, Co(II, and Pb(II ions. Compared to other metal ions the transport of Fe(III was the highest with selectivity order of Fe(III > Cr(III > Pb(II > Cu(II > Ni(II > Co(II. At optimum condition, Fe(III ion was transported through the membrane at 46.46%.   Keywords: poly(eugenyl oxyacetic acid, transport, liquid membrane, Fe (III, Cr(III, Cu(II, Ni(II, Co(II, and Pb(II ions

Relapsing-Remitting MS (RRMS)

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Development of high-performance chemical isotope labeling LC-MS for profiling the human fecal metabolome.

Science.gov (United States)

Xu, Wei; Chen, Deying; Wang, Nan; Zhang, Ting; Zhou, Ruokun; Huan, Tao; Lu, Yingfeng; Su, Xiaoling; Xie, Qing; Li, Liang; Li, Lanjuan

2015-01-20

Human fecal samples contain endogenous human metabolites, gut microbiota metabolites, and other compounds. Profiling the fecal metabolome can produce metabolic information that may be used not only for disease biomarker discovery, but also for providing an insight about the relationship of the gut microbiome and human health. In this work, we report a chemical isotope labeling liquid chromatography-mass spectrometry (LC-MS) method for comprehensive and quantitative analysis of the amine- and phenol-containing metabolites in fecal samples. Differential (13)C2/(12)C2-dansyl labeling of the amines and phenols was used to improve LC separation efficiency and MS detection sensitivity. Water, methanol, and acetonitrile were examined as an extraction solvent, and a sequential water-acetonitrile extraction method was found to be optimal. A step-gradient LC-UV setup and a fast LC-MS method were evaluated for measuring the total concentration of dansyl labeled metabolites that could be used for normalizing the sample amounts of individual samples for quantitative metabolomics. Knowing the total concentration was also useful for optimizing the sample injection amount into LC-MS to maximize the number of metabolites detectable while avoiding sample overloading. For the first time, dansylation isotope labeling LC-MS was performed in a simple time-of-flight mass spectrometer, instead of high-end equipment, demonstrating the feasibility of using a low-cost instrument for chemical isotope labeling metabolomics. The developed method was applied for profiling the amine/phenol submetabolome of fecal samples collected from three families. An average of 1785 peak pairs or putative metabolites were found from a 30 min LC-MS run. From 243 LC-MS runs of all the fecal samples, a total of 6200 peak pairs were detected. Among them, 67 could be positively identified based on the mass and retention time match to a dansyl standard library, while 581 and 3197 peak pairs could be putatively

Characterization of immortalized MARCO and SR-AI/II-deficient murine alveolar macrophage cell lines

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Imrich Amy

2008-05-01

Full Text Available Abstract Background Alveolar macrophages (AM avidly bind and ingest unopsonized inhaled particles and bacteria through class A scavenger receptors (SRAs MARCO and SR-AI/II. Studies to characterize the function of these SRAs have used AMs from MARCO or SR-AI/II null mice, but this approach is limited by the relatively low yield of AMs. Moreover, studies using both MARCO and SR-AI/II-deficient (MS-/- mice have not been reported yet. Hence, we sought to develop continuous cell lines from primary alveolar macrophages from MS-/- mice. Results We used in vitro infection of the primary AMs with the J2 retrovirus carrying the v-raf and v-myc oncogenes. Following initial isolation in media supplemented with murine macrophage colony-stimulating factor (M-CSF, we subcloned three AM cell lines, designated ZK-1, ZK-2 and ZK-6. These cell lines grow well in RPMI-1640-10% FBS in the absence of M-CSF. These adherent but trypsin-sensitive cell lines have a doubling time of approximately 14 hours, exhibit typical macrophage morphology, and express macrophage-associated cell surface Mac-1 (CD11b and F4/80 antigens. The cell lines show robust Fc-receptor dependent phagocytosis of opsonized red blood cells. Similar to freshly isolated AMs from MS-/- mice, the cell lines exhibit decreased phagocytosis of unopsonized titanium dioxide (TiO2, fluorescent latex beads and bacteria (Staphylococcus aureus compared with the primary AMs from wild type (WT C57BL/6 mice. Conclusion Our results indicated that three contiguous murine alveolar macrophage cell lines with MS-/- (ZK1, ZK2 and ZK6 were established successfully. These cell lines demonstrated macrophage morphology and functional activity. Interestingly, similar to freshly isolated AMs from MS-/- mice, the cell lines have a reduced, but not absent, ability to bind and ingest particles, with an altered pattern of blockade by scavenger receptor inhibitors. These cell lines will facilitate in vitro studies to further define

The EIPeptiDi tool: enhancing peptide discovery in ICAT-based LC MS/MS experiments

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Tradigo Giuseppe

2007-07-01

Full Text Available Abstract Background Isotope-coded affinity tags (ICAT is a method for quantitative proteomics based on differential isotopic labeling, sample digestion and mass spectrometry (MS. The method allows the identification and relative quantification of proteins present in two samples and consists of the following phases. First, cysteine residues are either labeled using the ICAT Light or ICAT Heavy reagent (having identical chemical properties but different masses. Then, after whole sample digestion, the labeled peptides are captured selectively using the biotin tag contained in both ICAT reagents. Finally, the simplified peptide mixture is analyzed by nanoscale liquid chromatography-tandem mass spectrometry (LC-MS/MS. Nevertheless, the ICAT LC-MS/MS method still suffers from insufficient sample-to-sample reproducibility on peptide identification. In particular, the number and the type of peptides identified in different experiments can vary considerably and, thus, the statistical (comparative analysis of sample sets is very challenging. Low information overlap at the peptide and, consequently, at the protein level, is very detrimental in situations where the number of samples to be analyzed is high. Results We designed a method for improving the data processing and peptide identification in sample sets subjected to ICAT labeling and LC-MS/MS analysis, based on cross validating MS/MS results. Such a method has been implemented in a tool, called EIPeptiDi, which boosts the ICAT data analysis software improving peptide identification throughout the input data set. Heavy/Light (H/L pairs quantified but not identified by the MS/MS routine, are assigned to peptide sequences identified in other samples, by using similarity criteria based on chromatographic retention time and Heavy/Light mass attributes. EIPeptiDi significantly improves the number of identified peptides per sample, proving that the proposed method has a considerable impact on the protein

Isotope ratio monitoring LC/MS (IRM-LC/MS): new applications

International Nuclear Information System (INIS)

Juchelka, D; Hilkert, A.; Krummen, M.

2005-01-01

With the introduction of compound specific isotope analysis by isotope ratio monitoring GC/ MS (IRM-GC/MS) the immediate demand for similar applications using HPLC was created. Many compounds of biological, medical, pharmaceutical and environmental interest are not volatile or too polar. Consequently, they cannot be directly analyzed by gas chromatography. In IRM-GC/MS the carrier is helium, which does not interfere with the essential combust ion step prior to isotope ratio mass spectrometry (IRMS). In opposite the LC mobile phase has inhibited a similar direct conversion up to now. All earlier IRM-LC/MS approaches were based on the removal of the liquid phase prior to combustion risking fractionation of the isotope ratios of the eluted compounds. To avoid such restrictions we developed a new continuous flow concept for the coupling of an HPLC system to the isotope ratio MS for 13 C/ 12C isotope ratio analysis. In the Finnigan LC IsoLink, the liquid phase is not removed from the sample prior to oxidation. The sample is oxidized still in the mobile phase followed by on-line separation of the CO 2 from the liquid phase and transfer into the isotope ratio MS. Therefore, this strategy is based on water and inorganic buffers as mobile phase. The new approach opens up a whole new world in the application of gas isotope ratio mass spectrometry. The 13 C/ 12 C ratio s of organic acids, amino acids, carbohydrates and nucleotides can now be measured. These components typically within a complex matrix are separated by liquid chromatography followed by on-line determination of the isotope ratios. The draw backs of using derivatization and off-line preparation procedures can now be over come. This new technique allow s studying biochemical cycles, running tracer experiments and determining the origin of components. Applications from different scientific areas such as biogeochemistry, molecular biology, and pharmacy as well as authenticity control o f foods will be presented

Ms. Mentor Unmasked

Science.gov (United States)

Krebs, Paula

2008-01-01

This article presents an interview with Emily Toth, who writes the monthly "Ms. Mentor" academic advice column in the "Chronicle of Higher Education" and teaches in the English department at Louisiana State University, in Baton Rouge. She is the author of "Ms. Mentor's Impeccable Advice for Women in Academia" (1997), "Inside Peyton Place: The Life…

Multi-objective optimization of Stirling engine systems using Front-based Yin-Yang-Pair Optimization

International Nuclear Information System (INIS)

Punnathanam, Varun; Kotecha, Prakash

2017-01-01

Highlights: • Efficient multi-objective optimization algorithm F-YYPO demonstrated. • Three Stirling engine applications with a total of eight cases. • Improvements in the objective function values of up to 30%. • Superior to the popularly used gamultiobj of MATLAB. • F-YYPO has extremely low time complexity. - Abstract: In this work, we demonstrate the performance of Front-based Yin-Yang-Pair Optimization (F-YYPO) to solve multi-objective problems related to Stirling engine systems. The performance of F-YYPO is compared with that of (i) a recently proposed multi-objective optimization algorithm (Multi-Objective Grey Wolf Optimizer) and (ii) an algorithm popularly employed in literature due to its easy accessibility (MATLAB’s inbuilt multi-objective Genetic Algorithm function: gamultiobj). We consider three Stirling engine based optimization problems: (i) the solar-dish Stirling engine system which considers objectives of output power, thermal efficiency and rate of entropy generation; (ii) Stirling engine thermal model which considers the associated irreversibility of the cycle with objectives of output power, thermal efficiency and pressure drop; and finally (iii) an experimentally validated polytropic finite speed thermodynamics based Stirling engine model also with objectives of output power and pressure drop. We observe F-YYPO to be significantly more effective as compared to its competitors in solving the problems, while requiring only a fraction of the computational time required by the other algorithms.

Relapsing-Remitting MS (RRMS)

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High accuracy determination of trace elements in NIST standard reference materials by isotope dilution ICP-MS

International Nuclear Information System (INIS)

Paulsen, P.J.; Beary, E.S.

1996-01-01

At NIST (National Institute of Standards and Technology), ICP-MS ID (inductively coupled mass spectrometry isotope dilution) has been used to certify a wide range of elements in a variety of materials with high accuracy. Both the chemical preparation and instrumental procedures are simpler than with other ID mass spectrometric techniques. The ICP-MS has picogram/ml detection limits for most elements using fixed operating parameters. Chemical separations are required only to remove an interference (from molecular ions as well as isobaric atoms), or to pre-concentrate the analyte. For example, chemical separations were required for the analysis of SRM 2711, Montana II Soil, but not for boron in peach leaves, SRM 1547.(3 refs., 3 tabs., 2 figs

Lung Cancer Serum Biomarker Discovery Using Label Free LC-MS/MS

Science.gov (United States)

Zeng, Xuemei; Hood, Brian L.; Zhao, Ting; Conrads, Thomas P.; Sun, Mai; Gopalakrishnan, Vanathi; Grover, Himanshu; Day, Roger S.; Weissfeld, Joel L.; Wilson, David O.; Siegfried, Jill M.; Bigbee, William L.