Development of an SRM method for absolute quantitation of MYDGF/C19orf10 protein.

Science.gov (United States)

Dwivedi, Ravi C; Krokhin, Oleg V; El-Gabalawy, Hani S; Wilkins, John A

2016-06-01

To develop a MS-based selected reaction monitoring (SRM) assay for quantitation of myeloid-derived growth factor (MYDGF) formerly chromosome 19 open reading frame (C19orf10). Candidate reporter peptides were identified in digests of recombinant MYDGF. Isotopically labeled forms of these reporter peptides were employed as internal standards for assay development. Two reference peptides were selected SYLYFQTFFK and GAEIEYAMAYSK with respective LOQ of 42 and 380 attomole per injection. Application of the assay to human serum and synovial fluid determined that the assay sensitivity was reduced and quantitation was not achievable. However, the partial depletion of albumin and immunoglobulin from synovial fluids provided estimates of 300-650 femtomoles per injection (0.7-1.6 nanomolar (nM) fluid concentrations) in three of the six samples analyzed. A validated sensitive assay for the quantitation of MYDGF in biological fluids was developed. However, the endogenous levels of MYDGF in such fluids are at or below the current levels of quantitation. The levels of MYDGF are lower than those previously reported using an ELISA. The current results suggest that additional steps may be required to remove high abundance proteins or to enrich MYDGF for SRM-based quantitation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Horizontally scaling dCache SRM with the Terracotta platform

International Nuclear Information System (INIS)

Perelmutov, T; Crawford, M; Moibenko, A; Oleynik, G

2011-01-01

The dCache disk caching file system has been chosen by a majority of LHC experiments' Tier 1 centers for their data storage needs. It is also deployed at many Tier 2 centers. The Storage Resource Manager (SRM) is a standardized grid storage interface and a single point of remote entry into dCache, and hence is a critical component. SRM must scale to increasing transaction rates and remain resilient against changing usage patterns. The initial implementation of the SRM service in dCache suffered from an inability to support clustered deployment, and its performance was limited by the hardware of a single node. Using the Terracotta platform[l], we added the ability to horizontally scale the dCache SRM service to run on multiple nodes in a cluster configuration, coupled with network load balancing. This gives site administrators the ability to increase the performance and reliability of SRM service to face the ever-increasing requirements of LHC data handling. In this paper we will describe the previous limitations of the architecture SRM server and how the Terracotta platform allowed us to readily convert single node service into a highly scalable clustered application.

Horizontally scaling dChache SRM with the Terracotta platform

International Nuclear Information System (INIS)

Perelmutov, T.; Crawford, M.; Moibenko, A.; Oleynik, G.

2011-01-01

The dCache disk caching file system has been chosen by a majority of LHC experiments Tier 1 centers for their data storage needs. It is also deployed at many Tier 2 centers. The Storage Resource Manager (SRM) is a standardized grid storage interface and a single point of remote entry into dCache, and hence is a critical component. SRM must scale to increasing transaction rates and remain resilient against changing usage patterns. The initial implementation of the SRM service in dCache suffered from an inability to support clustered deployment, and its performance was limited by the hardware of a single node. Using the Terracotta platform, we added the ability to horizontally scale the dCache SRM service to run on multiple nodes in a cluster configuration, coupled with network load balancing. This gives site administrators the ability to increase the performance and reliability of SRM service to face the ever-increasing requirements of LHC data handling. In this paper we will describe the previous limitations of the architecture SRM server and how the Terracotta platform allowed us to readily convert single node service into a highly scalable clustered application.

Certification of the methylmercury content in SRM 2977 mussel tissue (organic contaminants and trace elements) and SRM 1566b oyster tissue.

Science.gov (United States)

Tutschku, S; Schantz, M M; Horvat, M; Logar, M; Akagi, H; Emons, H; Levenson, M; Wise, S A

2001-02-01

The methylmercury content in two new marine bivalve mollusk tissue Standard Reference Materials (SRMs) has been certified using results of analyses from the National Institute of Standards and Technology (NIST) and two other laboratories. The certified concentrations of methylmercury were established based on the results from four and six different (independent) analytical methods, respectively, for SRM 1566b Oyster Tissue (13.2 +/- 0.7 microg/kg) and SRM 2977 Mussel Tissue (organic contaminants and trace elements) (36.2 +/- 1.7 microg/kg). The certified concentration of methylmercury in SRM 1566b is among the lowest in any certified reference material (CRM).

Characterization of sampling behavior for multielements in NIST SRM 2703

International Nuclear Information System (INIS)

Huang Donghui; Sun Hongchao; Ni Bangfa; Tian Weizhi; Wang Pingsheng; Liu CunXiong; Zhang Guiying; Xiao Caijin; Zhang Haiqing; Zhao Changjun; Zhang Yuanxun

2011-01-01

Sampling behavior of multielements for NIST SRM 2703, a marine sediment, was studied with sample sizes from 1 mg down to ng level by a combination of INAA, PIXE and SRXRF. On 1 mg sample size level, sampling behavior for multielements in NIST SRM 2703 and its parent SRM 2702 were comparatively characterized by using INAA combining with Ingamells model. Results showed that sampling uncertainties for 12 elements of both materials were found to be better than 1%, and those of four other elements in SRM 2703 better than in SRM 2702. At sample sizes not able to be accurately weighed (<1 mg), PIXE and SRXRF were used and the effective sample sizes estimated. Sampling uncertainties for nine elements were found to be better than 1% at sample sizes of tenth mg level, and those for six elements better than 10% on ng levels. (author)

Assessment of stability of trace elements in two natural matrix environmental standard reference materials. NIST-SRM 1547 Peach leaves and NIST-SRM 1566a Oyster Tissue

International Nuclear Information System (INIS)

Mackey, E.A.; Spatz, R.O.

2009-01-01

The NIST program for environmental Standard Reference Materials (SRM) includes materials covering a range of matrices, mass fraction values and analytes. For many SRMs, mass fraction data are accumulated, incidentally, over time, as these are used routinely for quality assurance purposes. Although these are not formal stability studies, data generated may be useful in assessing stability. To evaluate the potential for assessing material stability from incidental use of SRMs, results of neutron activation analysis performed from 1992 through 2008 were compiled for SRM 1547 Peach Leaves and SRM 1566a Oyster Tissue. Results indicate that incidental use of SRMs yields useful information on SRM stability. (author)

Quantitative and Selective Analysis of Feline Growth Related Proteins Using Parallel Reaction Monitoring High Resolution Mass Spectrometry.

Directory of Open Access Journals (Sweden)

Mårten Sundberg

Full Text Available Today immunoassays are widely used in veterinary medicine, but lack of species specific assays often necessitates the use of assays developed for human applications. Mass spectrometry (MS is an attractive alternative due to high specificity and versatility, allowing for species-independent analysis. Targeted MS-based quantification methods are valuable complements to large scale shotgun analysis. A method referred to as parallel reaction monitoring (PRM, implemented on Orbitrap MS, has lately been presented as an excellent alternative to more traditional selected reaction monitoring/multiple reaction monitoring (SRM/MRM methods. The insulin-like growth factor (IGF-system is not well described in the cat but there are indications of important differences between cats and humans. In feline medicine IGF-I is mainly analyzed for diagnosis of growth hormone disorders but also for research, while the other proteins in the IGF-system are not routinely analyzed within clinical practice. Here, a PRM method for quantification of IGF-I, IGF-II, IGF binding protein (BP -3 and IGFBP-5 in feline serum is presented. Selective quantification was supported by the use of a newly launched internal standard named QPrEST™. Homology searches demonstrated the possibility to use this standard of human origin for quantification of the targeted feline proteins. Excellent quantitative sensitivity at the attomol/μL (pM level and selectivity were obtained. As the presented approach is very generic we show that high resolution mass spectrometry in combination with PRM and QPrEST™ internal standards is a versatile tool for protein quantitation across multispecies.

On the effect of grain burnback on STS-SRM fragment velocity

International Nuclear Information System (INIS)

Eck, M.B.; Mukunda, M.

1991-01-01

Concerns raised during the Ulysses Final Safety Analysis Review (FSAR) process called the solid rocket motor (SRM) fragment velocity prediction model into question. The specific area of concern was that there was a section of the SRM casing which was exposed to SRM chamber pressure as the grain (fuel) was consumed. These questions centered on the velocity of fragments which originated from the field joint region given that failure occurred between 37 and 72 seconds mission elapsed time (MET). Two dimensional coupled Eulerian-Lagrangian calculations were performed to assess the hot gas flow field which resulted from SRM casing fragmentation. The fragment to gas interface-pressure time-history obtained from these analyses was reduced to a boundary condition algorithm which was applied to an explicit-time-integration, finite element, three dimensional shell model of the SRM casing and unburned fuel. The results of these calculations showed that the velocity of fragments originating in the field joint was adequately described by the range of velocities given in the Shuttle Data Book (1988). Based on these results, no further analyses were required, and approval was obtained from the Launch Abort Subpanel of the Interagency Nuclear Safety Review Panel to use the SRM fragment velocity environments presented in the Ulysses FSAR (1990)

Analytical applications of ion/molecule reactions in a triple quadrupole mass spectrometer

International Nuclear Information System (INIS)

Kinter, M.T.

1986-01-01

The development of triple quadrupole mass spectrometers as a means of performing tandem mass spectrometry has provided a versatile instrument on which the ion/molecule reactions of a mass selected ion can be studied. This dissertation details the application of ion/molecule reactions in a triple quadrupole to two analytical problems. Part I. Ion/Molecule Reactions of Ammonia with Translationally Excited C 2 H 5 O + /Ions. The ability to impart low center-of-mass translational energies, which upon collision are converted into internal energy, allows the observation of reactions that require energy input. In addition, the systematic variation of the ion kinetic energy, often referred to as energy-resolved mass spectrometer, adds another dimension to the mass spectrum and can allow the observation of thresholds for reactions requiring energy input. This investigation develops methods for determining these thresholds. Part 2. The Use of Ion/Molecule Reactions in selected Reaction Monitoring GC/MSD/MS Analyses. An approach to improving the selectivity of an analysis is to improve the selectivity of the detection method. In GC/MS, one method has been to monitor a selected fragmentation reaction, either metastable or collisionally activated, in a selected reaction monitoring (SRM) analysis. This develops the use of ion/molecule reactions for selected reaction monitoring analyses

Optimization of technology SRM (Supply Relationship Management) in oil companies supply; Otimizacao de tecnologia SRM (Supply Relationship Management) em empresas da cadeia do petroleo

Energy Technology Data Exchange (ETDEWEB)

Jovine, Renata Machado; Bastos, Luciana de Barros [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil)

2004-07-01

Recently, becomes very important improve the Supplier Relationship in order to the enterprises reduce costs and increase their efficiency. By that fact, in the last years, people started talking about Supplier Relationship Management - SRM and technologies are being developed to support this management. At Petroleum's Industry, every source should be at the right place, at the right time and should have quality otherwise the damages can be disastrous, considering the high cost of the equipment and environmental questions. So, this project intent to study the SRM of one enterprise of the petroleum area in order to analyze this technology, study references and analyzing the practices related to SRM, criticize and propose improvements that could be done. In this study, was concluded that technology is being developed but there is still place for improvement in the practice. (author)

Certification of methylmercury content in two fresh-frozen reference materials: SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis)

International Nuclear Information System (INIS)

Davis, W.C.; Christopher, S.J.; Pugh, Rebecca S.; Donard, O.F.X.; Krupp, Eva A.; Point, David; Horvat, Milena; Gibicar, D.; Kljakovic-Gaspic, Z.; Porter, Barbara J.; Schantz, Michele M.

2007-01-01

This paper describes the development of two independent analytical methods for the extraction and quantification of methylmercury from marine biota. The procedures involve microwave extraction, followed by derivatization and either headspace solid-phase microextraction (SPME) with a polydimethylsiloxane (PDMS)-coated silica fiber or back-extraction into iso-octane. The identification and quantification of the extracted compounds is carried out by capillary gas chromatography/mass spectrometric (GC/MS) and inductively coupled plasma mass spectrometric (GC/ICP-MS) detection. Both methods were validated for the determination of methylmercury (MeHg) concentrations in a variety of biological standard reference materials (SRMs) including fresh-frozen tissue homogenates of SRM 1946 Lake Superior fish tissue and SRM 1974a organics in mussel tissue (Mytilus edulis) and then applied to the certification effort of SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis). While past certifications of methylmercury in tissue SRMs have been based on two independent methods from the National Institute of Standards and Technology (NIST) and participating laboratories, the methods described within provide improved protocols and will allow future certification efforts to be based on at least two independent analytical methods within NIST. (orig.)

Certification of methylmercury content in two fresh-frozen reference materials: SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis)

Energy Technology Data Exchange (ETDEWEB)

Davis, W.C.; Christopher, S.J.; Pugh, Rebecca S. [National Institute of Standards and Technology (NIST), Hollings Marine Laboratory, Analytical Chemistry Division, Charleston, SC (United States); Donard, O.F.X.; Krupp, Eva A. [LCABIE/CNRS Helioparc Pau-Pyrenees, Pau (France); Point, David [National Institute of Standards and Technology (NIST), Hollings Marine Laboratory, Analytical Chemistry Division, Charleston, SC (United States); LCABIE/CNRS Helioparc Pau-Pyrenees, Pau (France); Horvat, Milena; Gibicar, D. [Jozef Stefan Institute, Ljubljana (Slovenia); Kljakovic-Gaspic, Z. [Jozef Stefan Institute, Ljubljana (Slovenia); Institute for Medical Research and Occupational Health, Zagreb (Croatia); Porter, Barbara J.; Schantz, Michele M. [National Institute of Standards and Technology (NIST), Analytical Chemistry Division, Gaithersburg, MD (United States)

2007-04-15

This paper describes the development of two independent analytical methods for the extraction and quantification of methylmercury from marine biota. The procedures involve microwave extraction, followed by derivatization and either headspace solid-phase microextraction (SPME) with a polydimethylsiloxane (PDMS)-coated silica fiber or back-extraction into iso-octane. The identification and quantification of the extracted compounds is carried out by capillary gas chromatography/mass spectrometric (GC/MS) and inductively coupled plasma mass spectrometric (GC/ICP-MS) detection. Both methods were validated for the determination of methylmercury (MeHg) concentrations in a variety of biological standard reference materials (SRMs) including fresh-frozen tissue homogenates of SRM 1946 Lake Superior fish tissue and SRM 1974a organics in mussel tissue (Mytilus edulis) and then applied to the certification effort of SRM 1947 Lake Michigan fish tissue and SRM 1974b organics in mussel tissue (Mytilus edulis). While past certifications of methylmercury in tissue SRMs have been based on two independent methods from the National Institute of Standards and Technology (NIST) and participating laboratories, the methods described within provide improved protocols and will allow future certification efforts to be based on at least two independent analytical methods within NIST. (orig.)

Negative reactions to monitoring: Do they undermine the ability of monitoring to protect adolescents?

Science.gov (United States)

Laird, Robert D; Zeringue, Megan M; Lambert, Emily S

2018-02-01

This study focused on adolescents' negative reactions to parental monitoring to determine whether parents should avoid excessive monitoring because adolescents find monitoring behaviors to be over-controlling and privacy invasive. Adolescents (n = 242, M age = 15.4 years; 51% female) reported monitoring, negative reactions, warmth, antisocial behavior, depressive symptoms, and disclosure. Adolescents additionally reported antisocial behavior, depressive symptoms, and disclosure one to two years later. In cross-sectional analyses, less monitoring but more negative reactions were linked with less disclosure, suggesting that negative reactions can undermine parents' ability to obtain information. Although monitoring behaviors were not related to depressive symptoms, more negative reactions were linked with more depressive symptoms, suggesting that negative reactions also may increase depressive symptoms as a side effect of monitoring behavior. Negative reactions were not linked to antisocial behavior. There were no longitudinal links between negative reactions and changes in disclosure, antisocial behavior, or depressive symptoms. Copyright © 2017. Published by Elsevier Ltd.

Numerical Simulation of Desulfurization Behavior in Gas-Stirred Systems Based on Computation Fluid Dynamics-Simultaneous Reaction Model (CFD-SRM) Coupled Model

Science.gov (United States)

Lou, Wentao; Zhu, Miaoyong

2014-10-01

A computation fluid dynamics-simultaneous reaction model (CFD-SRM) coupled model has been proposed to describe the desulfurization behavior in a gas-stirred ladle. For the desulfurization thermodynamics, different models were investigated to determine sulfide capacity and oxygen activity. For the desulfurization kinetic, the effect of bubbly plume flow, as well as oxygen absorption and oxidation reactions in slag eyes are considered. The thermodynamic and kinetic modification coefficients are proposed to fit the measured data, respectively. Finally, the effects of slag basicity and gas flow rate on the desulfurization efficiency are investigated. The results show that as the interfacial reactions (Al2O3)-(FeO)-(SiO2)-(MnO)-[S]-[O] simultaneous kinetic equilibrium is adopted to determine the oxygen activity, and the Young's model with the modification coefficient R th of 1.5 is adopted to determine slag sulfide capacity, the predicted sulfur distribution ratio LS agrees well with the measured data. With an increase of the gas blowing time, the predicted desulfurization rate gradually decreased, and when the modification parameter R k is 0.8, the predicted sulfur content changing with time in ladle agrees well with the measured data. If the oxygen absorption and oxidation reactions in slag eyes are not considered in this model, then the sulfur removal rate in the ladle would be overestimated, and this trend would become more obvious with an increase of the gas flow rate and decrease of the slag layer height. With the slag basicity increasing, the total desulfurization ratio increases; however, the total desulfurization ratio changes weakly as the slag basicity exceeds 7. With the increase of the gas flow rate, the desulfurization ratio first increases and then decreases. When the gas flow rate is 200 NL/min, the desulfurization ratio reaches a maximum value in an 80-ton gas-stirred ladle.

An Efficient and Simplified Model for Forecasting using SRM

Directory of Open Access Journals (Sweden)

Hafiz Muhammad Shahzad Asif

2014-01-01

Full Text Available Learning form continuous financial systems play a vital role in enterprise operations. One of the most sophisticated non-parametric supervised learning classifiers, SVM (Support Vector Machines, provides robust and accurate results, however it may require intense computation and other resources. The heart of SLT (Statistical Learning Theory, SRM (Structural Risk Minimization Principle can also be used for model selection. In this paper, we focus on comparing the performance of model estimation using SRM with SVR (Support Vector Regression for forecasting the retail sales of consumer products. The potential benefits of an accurate sales forecasting technique in businesses are immense. Retail sales forecasting is an integral part of strategic business planning in areas such as sales planning, marketing research, pricing, production planning and scheduling. Performance comparison of support vector regression with model selection using SRM shows comparable results to SVR but in a computationally efficient manner. This research targeted the real life data to conclude the results after investigating the computer generated datasets for different types of model building

An efficient and simplified model for forecasting using SRM

International Nuclear Information System (INIS)

Asif, H.M.; Hyat, M.F.; Ahmad, T.

2014-01-01

Learning form continuous financial systems play a vital role in enterprise operations. One of the most sophisticated non-parametric supervised learning classifiers, SVM (Support Vector Machines), provides robust and accurate results, however it may require intense computation and other resources. The heart of SLT (Statistical Learning Theory), SRM (Structural Risk Minimization )Principle can also be used for model selection. In this paper, we focus on comparing the performance of model estimation using SRM with SVR (Support Vector Regression) for forecasting the retail sales of consumer products. The potential benefits of an accurate sales forecasting technique in businesses are immense. Retail sales forecasting is an integral part of strategic business planning in areas such as sales planning, marketing research, pricing, production planning and scheduling. Performance comparison of support vector regression with model selection using SRM shows comparable results to SVR but in a computationally efficient manner. This research targeted the real life data to conclude the results after investigating the computer generated datasets for different types of model building. (author)

Rhythmic Behavior Is Controlled by the SRm160 Splicing Factor in Drosophila melanogaster.

Science.gov (United States)

Beckwith, Esteban J; Hernando, Carlos E; Polcowñuk, Sofía; Bertolin, Agustina P; Mancini, Estefania; Ceriani, M Fernanda; Yanovsky, Marcelo J

2017-10-01

Circadian clocks organize the metabolism, physiology, and behavior of organisms throughout the day-night cycle by controlling daily rhythms in gene expression at the transcriptional and post-transcriptional levels. While many transcription factors underlying circadian oscillations are known, the splicing factors that modulate these rhythms remain largely unexplored. A genome-wide assessment of the alterations of gene expression in a null mutant of the alternative splicing regulator SR-related matrix protein of 160 kDa (SRm160) revealed the extent to which alternative splicing impacts on behavior-related genes. We show that SRm160 affects gene expression in pacemaker neurons of the Drosophila brain to ensure proper oscillations of the molecular clock. A reduced level of SRm160 in adult pacemaker neurons impairs circadian rhythms in locomotor behavior, and this phenotype is caused, at least in part, by a marked reduction in period ( per ) levels. Moreover, rhythmic accumulation of the neuropeptide PIGMENT DISPERSING FACTOR in the dorsal projections of these neurons is abolished after SRm160 depletion. The lack of rhythmicity in SRm160-downregulated flies is reversed by a fully spliced per construct, but not by an extra copy of the endogenous locus, showing that SRm160 positively regulates per levels in a splicing-dependent manner. Our findings highlight the significant effect of alternative splicing on the nervous system and particularly on brain function in an in vivo model. Copyright © 2017 by the Genetics Society of America.

Capillary zone electrophoresis-multiple reaction monitoring from 100 pg of RAW 264.7 cell lysate digest.

Science.gov (United States)

Sun, Liangliang; Li, Yihan; Champion, Matthew M; Zhu, Guijie; Wojcik, Roza; Dovichi, Norman J

2013-06-07

Capillary zone electrophoresis-multiple/single reaction monitoring (CZE-MRM/SRM), which employed an electrokinetically driven sheath-flow electrospray interface, was used for the rapid and highly sensitive detection of protein analytes in complex tryptic digests. MRM channels were developed against a commercial exponential mixture of bovine proteins. Five proteins spanning four orders of magnitude concentration range were confidently detected from only 2.5 ng of the digest mixture; the mass detection limits (S/N = 3) of two detected proteins, alpha-casein and glutamate dehydrogenase were about 600 zmol and 30 amol, respectively. This technique was then applied to a RAW 264.7 cell lysate digest. Three proteins were confidently and reproducibly detected from 100 pg of this digest. The sample amount corresponds to the approximate protein content from a single cell, which suggests that CZE-MRM may be a useful analytical tool in chemical cytometry. In addition to providing highly sensitive detection of proteins in complex mixtures, this system is highly rapid; migration time of the protein digests was less than 10 min.

Polycyclic aromatic hydrocarbons (PAHs) in a coal tar standard reference material - SRM 1597a updated

Energy Technology Data Exchange (ETDEWEB)

Wise, Stephen A.; Poster, Dianne L.; Rimmer, Catherine A.; Schubert, Patricia; Sander, Lane C.; Schantz, Michele M. [National Institute of Standards and Technology (NIST), Analytical Chemistry Division, Gaithersburg, MD (United States); Leigh, Stefan D. [National Institute of Standards and Technology (NIST), Statistical Engineering Division, Gaithersburg, MD (United States); Moessner, Stephanie [National Institute of Standards and Technology (NIST), Analytical Chemistry Division, Gaithersburg, MD (United States); GMP/Comparator Labs, Werthenstein Chemie AG, Industrie Nord, Schachen (Switzerland)

2010-09-15

SRM 1597 Complex Mixture of Polycyclic Aromatic Hydrocarbons from Coal Tar, originally issued in 1987, was recently reanalyzed and reissued as SRM 1597a with 34 certified, 46 reference, and 12 information concentrations (as mass fractions) for polycyclic aromatic hydrocarbons (PAHs) and polycyclic aromatic sulfur heterocycles (PASHs) including methyl-substituted PAHs and PASHs. The certified and reference concentrations (as mass fractions) were based on results of analyses of the coal tar material using multiple analytical techniques including gas chromatography/mass spectrometry on four different stationary phases and reversed-phase liquid chromatography. SRM 1597a is currently the most extensively characterized SRM for PAHs and PASHs. (orig.)

Predicting core losses and efficiency of SRM in continuous current mode of operation using improved analytical technique

International Nuclear Information System (INIS)

Parsapour, Amir; Dehkordi, Behzad Mirzaeian; Moallem, Mehdi

2015-01-01

In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated

Predicting core losses and efficiency of SRM in continuous current mode of operation using improved analytical technique

Energy Technology Data Exchange (ETDEWEB)

Parsapour, Amir, E-mail: amirparsapour@gmail.com [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Dehkordi, Behzad Mirzaeian, E-mail: mirzaeian@eng.ui.ac.ir [Department of Electrical Engineering, University of Isfahan, Isfahan (Iran, Islamic Republic of); Moallem, Mehdi, E-mail: moallem@cc.iut.ac.ir [Department of Electrical Engineering, Isfahan University of Technology, Isfahan (Iran, Islamic Republic of)

2015-03-15

In applications in which the high torque per ampere at low speed and rated power at high speed are required, the continuous current method is the best solution. However, there is no report on calculating the core loss of SRM in continuous current mode of operation. Efficiency and iron loss calculation which are complex tasks in case of conventional mode of operation is even more involved in continuous current mode of operation. In this paper, the Switched Reluctance Motor (SRM) is modeled using finite element method and core loss and copper loss of SRM in discontinuous and continuous current modes of operation are calculated using improved analytical techniques to include the minor loop losses in continuous current mode of operation. Motor efficiency versus speed in both operation modes is obtained and compared. - Highlights: • Continuous current method for Switched Reluctance Motor (SRM) is explained. • An improved analytical technique is presented for SRM core loss calculation. • SRM losses in discontinuous and continuous current operation modes are presented. • Effect of mutual inductances on SRM performance is investigated.

Analysis of alpha-synuclein in malignant melanoma - development of a SRM quantification assay.

Directory of Open Access Journals (Sweden)

Charlotte Welinder

Full Text Available Globally, malignant melanoma shows a steady increase in the incidence among cancer diseases. Malignant melanoma represents a cancer type where currently no biomarker or diagnostics is available to identify disease stage, progression of disease or personalized medicine treatment. The aim of this study was to assess the tissue expression of alpha-synuclein, a protein implicated in several disease processes, in metastatic tissues from malignant melanoma patients. A targeted Selected Reaction Monitoring (SRM assay was developed and utilized together with stable isotope labeling for the relative quantification of two target peptides of alpha-synuclein. Analysis of alpha-synuclein protein was then performed in ten metastatic tissue samples from the Lund Melanoma Biobank. The calibration curve using peak area ratio (heavy/light versus concentration ratios showed linear regression over three orders of magnitude, for both of the selected target peptide sequences. In support of the measurements of specific protein expression levels, we also observed significant correlation between the protein and mRNA levels of alpha-synuclein in these tissues. Investigating levels of tissue alpha-synuclein may add novel aspect to biomarker development in melanoma, help to understand disease mechanisms and ultimately contribute to discriminate melanoma patients with different prognosis.

Application of snowmelt runoff model (SRM in mountainous watersheds: A review

Directory of Open Access Journals (Sweden)

Shalamu Abudu

2012-06-01

Full Text Available The snowmelt runoff model (SRM has been widely used in simulation and forecast of streamflow in snow-dominated mountainous basins around the world. This paper presents an overall review of worldwide applications of SRM in mountainous watersheds, particularly in data-sparse watersheds of northwestern China. Issues related to proper selection of input climate variables and parameters, and determination of the snow cover area (SCA using remote sensing data in snowmelt runoff modeling are discussed through extensive review of literature. Preliminary applications of SRM in northwestern China have shown that the model accuracies are relatively acceptable although most of the watersheds lack measured hydro-meteorological data. Future research could explore the feasibility of modeling snowmelt runoff in data-sparse mountainous watersheds in northwestern China by utilizing snow and glacier cover remote sensing data, geographic information system (GIS tools, field measurements, and innovative ways of model parameterization.

Reference Cross Sections for Charged-particle Monitor Reactions

Science.gov (United States)

Hermanne, A.; Ignatyuk, A. V.; Capote, R.; Carlson, B. V.; Engle, J. W.; Kellett, M. A.; Kibédi, T.; Kim, G.; Kondev, F. G.; Hussain, M.; Lebeda, O.; Luca, A.; Nagai, Y.; Naik, H.; Nichols, A. L.; Nortier, F. M.; Suryanarayana, S. V.; Takács, S.; Tárkányi, F. T.; Verpelli, M.

2018-02-01

Evaluated cross sections of beam-monitor reactions are expected to become the de-facto standard for cross-section measurements that are performed over a very broad energy range in accelerators in order to produce particular radionuclides for industrial and medical applications. The requirements for such data need to be addressed in a timely manner, and therefore an IAEA coordinated research project was launched in December 2012 to establish or improve the nuclear data required to characterise charged-particle monitor reactions. An international team was assembled to recommend more accurate cross-section data over a wide range of targets and projectiles, undertaken in conjunction with a limited number of measurements and more extensive evaluations of the decay data of specific radionuclides. Least-square evaluations of monitor-reaction cross sections including uncertainty quantification have been undertaken for charged-particle beams of protons, deuterons, 3He- and 4He-particles. Recommended beam monitor reaction data with their uncertainties are available at the IAEA-NDS medical portal http://www-nds.iaea.org/medical/monitor_reactions.html.

Smart Rack Monitor for the Linac control system

International Nuclear Information System (INIS)

Shtirbu, S.; Goodwin, R.W.; McCrory, E.S.; Shea, M.F.

1991-01-01

The Smart Rack Monitor (SRM) is a low-cost, one board, data-acquisition module for the upgraded Linac control system at Fermilab. The SRM is based on the Motorola MC68332 microcontroller in the Business Card Computer (BCC) configuration. It is connected to the Linac local control station (to be referred to as Local Station) by an Arcnet LAN, and can be located close to the controlled hardware. Each Local Station is connected to several SRMs. The SRM has 64 A-D channels, sixteen D-A channels, and eight bytes of digital I/O on the mother board. Software Components Group's pSOS is the SRM's kernel. The SRM's software is cross-developed on VAX/VMS in C. The SRM does not have an attached console and is fully controlled by the Local Station. It performs data acquisition and settings, as directed by the Local Station. Its existence is transparent to the rest of the control system. The SRM supports code updates downloading from the VAX, through the Local Station

Thermal conductivity and electrical resistivity standard reference materials: tungsten SRM's 730 and 799, from 4 to 30000K. Final report

International Nuclear Information System (INIS)

Hust, J.G.; Giarratano, P.J.

1975-09-01

A historical review of the development of thermophysical Standard Reference Materials, SRM's, is given and selection criteria of SRM's are listed. Thermal conductivity and electrical resistivity data for arc cast and sintered tungsten are compiled, analyzed, and correlated. Recommended values of thermal conductivity (SRM 730) and electrical resistivity (SRM 799) for these lots of tungsten are presented for the range 4 to 3000 0 K

Neutron activation analysis of NBS oyster tissue (SRM 1566) and IAEA animal bone (H-5)

International Nuclear Information System (INIS)

Lepel, E.A.; Laul, J.C.

1984-03-01

Instrumental and radiochemical neutron activation analysis (INAA and RNAA) were employed to measure about 37 major, minor, and trace elements in two standard reference materials: oyster tissue (SRM 1566) supplied by the National Bureau of Standards (NBS) and animal bone (H-5) supplied by the International Atomic Energy Agency (IAEA). Wherever the comparison exists, our data show excellent agreement with accepted values for each SRM. These SRM's are useful as reference standards for the analysis of biological materials. Additionally, the chondritic normalized rare earth element pattern of animal bone behaves as a smooth function of the ionic radii, as previously observed for biological materials

Characterization of reaction conditions providing rapid and specific cysteine alkylation for peptide-based mass spectrometry.

Science.gov (United States)

Paulech, Jana; Solis, Nestor; Cordwell, Stuart J

2013-01-01

Alkylation converts Cys thiols to thioethers and prevents unwanted side reactions, thus facilitating mass spectrometric identification of Cys-containing peptides. Alkylation occurs preferentially at Cys due to its high nucleophilicity, however reactions at other such sites are possible. N-ethylmaleimide (NEM) shows rapid reaction kinetics with Cys and careful definition of reaction conditions results in little reactivity at other sites. Analysis of a protein standard alkylated under differing reaction conditions (pH, NEM concentrations and reaction times) was performed using liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) and selected reaction monitoring (SRM) of NEM-modified and unmodified peptide pairs. Mis-alkylation sites at primary and secondary amines were identified and limited to one equivalent of NEM. No evidence for hydroxyl or thioether alkylation was observed. Improved specificity was achieved by restricting the pH below neutral, NEM concentration below 10mM and/or reaction time to below 5min. Maximal removal of Cys activity was observed in tissue homogenates at 40mM NEM within 1min, dependent upon efficient protein denaturation. SRM assays identified peptide-specific levels of mis-alkylation, indicating that NEM-modified to unmodified ratios did not exceed 10%, with the exception of Cys alkylation that proceeded to 100%, and some Lys residues that resulted in tryptic missed cleavages. High reactivity was observed for His residues considering their relatively low abundance. These data indicate that rapid and specific Cys alkylation is possible with NEM under relatively mild conditions, with more abrasive conditions leading to increased non-specific alkylation without appreciable benefit for MS-based proteomics. Copyright © 2012 Elsevier B.V. All rights reserved.

Warmth and legitimacy beliefs contextualize adolescents' negative reactions to parental monitoring.

Science.gov (United States)

LaFleur, Laura K; Zhao, Yinan; Zeringue, Megan M; Laird, Robert D

2016-08-01

This study sought to identify conditions under which parents' monitoring behaviors are most strongly linked to adolescents' negative reactions (i.e., feelings of being controlled and invaded). 242 adolescents (49.2% male; M age = 15.4 years) residing in the United States of America reported parental monitoring and warmth, and their own feelings of being controlled and invaded and beliefs in the legitimacy of parental authority. Analyses tested whether warmth and legitimacy beliefs moderate and/or suppress the link between parents' monitoring behaviors and adolescents' negative reactions. Monitoring was associated with more negative reactions, controlling for legitimacy beliefs and warmth. More monitoring was associated with more negative reactions only at weaker levels of legitimacy beliefs, and at lower levels of warmth. The link between monitoring and negative reactions is sensitive to the context within which monitoring occurs with the strongest negative reactions found in contexts characterized by low warmth and weak legitimacy beliefs. Copyright © 2016 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

R dump converter without DC link capacitor for an 8/6 SRM: experimental investigation.

Science.gov (United States)

Kavitha, Pasumalaithevan; Umamaheswari, Bhaskaran

2015-01-01

The objective of this paper is to investigate the performance of 8/6 switched reluctance motor (SRM) when excited with sinusoidal voltage. The conventional R dump converter provides DC excitation with the help of capacitor. In this paper the converter used is the modified R dump converter without DC link capacitor providing AC or sinusoidal excitation. Torque ripple and speed ripple are investigated based on hysteresis current control. Constant and sinusoidal current references are considered for comparison in both DC and AC excitation. Extensive theoretical and experimental investigations are made to bring out the merits and demerits of AC versus DC excitation. It is shown that the constructionally simple SRM can be favorably controlled with simple R dump converter with direct AC excitation without need for DC link capacitor. A 4-phase 8/6 0.5 kW SRM is used for experimentation.

Calibrating NIST SRM 683 as A New International Reference Standard for Zn Isotopes

Science.gov (United States)

Yang, Y.; Zhang, X.; Yu, H.; Huang, F.

2017-12-01

Zinc isotopes have been widely applied in the cosmochemical, geochemical, and environmental studies (Moynier et al. 2017). Obtaining precise Zn isotopic data for inter-laboratory comparison is a prerequisite to these applications. Currently, the JMC3-0749L is the primary reference standard for Zn isotopes (Albarède 2004), but it is not commercially available now. Thus, it is necessary to calibrate a new international primary reference standard for Zn isotopic analysis. Chen et al. (2016) showed that NIST SRM 683 (a pure Zn metal nugget of 140 grams) has a δ66ZnJMC of 0.12‰, which is falling within the range of natural Zn isotopic compositions, and it may a good candidate for the next generation of international reference standard (Chen et al. 2016). In order to further examine whether NIST SRM 683 has a homogeneous Zn isotopic composition, we measured more NIST SRM 683 by double-spike methods using MC-ICPMS (Conway et al. 2013). The metal nuggets of NIST SRM 683 were intensively sampled by micro-drilling. Zinc isotope analyses for two nuggets show that they have δ66Zn of 0.14 ± 0.02‰ (2SD, N = 32) and 0.13 ± 0.02‰ (2SD, N = 33), respectively. These values are similar to those of two Zn metal nuggets (0.11 ± 0.02‰ vs. 0.12 ± 0.02‰) reported previously by Chen et al. (2016). We fully dissolved one nugget, producing pure Zn solution with identical Zn isotopic composition with the drilling samples. All results strongly support that NIST SRM 683 is homogeneous in Zn isotopic compositions which could be an ideal candidate for the next reference for Zn isotopes. Tests on more metal nuggets will be performed in a few months for further confirming the Zn isotope compositions and homogeneity. Reference: Albarède et al., 2004. 'The stable isotope geochemistry of copper and zinc', Reviews in Mineralogy and Geochemistry, 55: 409-27. Chen et al., 2016. 'Zinc Isotopic Compositions of NIST SRM 683 and Whole-Rock Reference Materials', Geostandards and

Total and isoform-specific quantitative assessment of circulating Fibulin-1 using selected reaction monitoring mass spectrometry and time-resolved immunofluorometry

DEFF Research Database (Denmark)

Overgaard, Martin; Cangemi, Claudia; Jensen, Martin L

2015-01-01

biomarker fibulin-1 and its circulating isoforms in human plasma. EXPERIMENTAL DESIGN:: We used bioinformatics analysis to predict total and isoform-specific tryptic peptides for absolute quantitation using SRM-MS. Fibulin-1 was quantitated in plasma by nanoflow-LC-SRM-MS in undepleted plasma and time......PURPOSE:: Targeted proteomics using SRM-MS combined with stable isotope dilution has emerged as a promising quantitative technique for the study of circulating protein biomarkers. The purpose of this study was to develop and characterize robust quantitative assays for the emerging cardiovascular......-resolved immunofluorometric assay (TRIFMA). Both methods were validated and compared to a commercial ELISA (CircuLex). Molecular size determination was performed under native conditions by SEC analysis coupled to SRM-MS and TRIFMA. RESULTS:: Absolute quantitation of total fibulin-1, isoforms -1C and -1D was performed by SRM...

APPLICATION OF NEUTRON ACTIVATION ANALYSIS IN CHARACTERIZATION OF ENVIRONMENTAL SRM SAMPLES

Directory of Open Access Journals (Sweden)

Diah Dwiana Lestiani

2010-06-01

Full Text Available Neutron activation analysis (NAA is a nuclear technique that is excellent, multi-elemental, sensitive and has limit detection up to nanogram level. The application of NAA in analysis of Standard Reference Material (SRM National Institute of Standard Technology (NIST 1633b Coal Fly Ash and SRM NIST 1646a Estuarine Sediment was carried out for NAA laboratory inter-comparison program. The samples were distributed by Technology Centre for Nuclear Industry Material, National Nuclear Energy Agency as a coordinator of the inter-comparison program. The samples were irradiated in rabbit facility of G.A. Siwabessy reactor with neutron flux ~ 1013 n.cm-2.s-1, and counted with HPGe spectrometry gamma detector. Several trace elements in these samples were detected. The concentration of Al, Mg, K, Na and Ti in SRM NIST 1633b were 15.11, 7.35, 2.09, 0.192 and 0.756% respectively and the concentration of As, Cr, Mn, Se, V, Sb, Co, Cs, La, Sc and Sm were 137.0, 195.6, 129.4, 9.61, 305.8, 5.45, 56.2, 11.18, 83.73, 41.1 and 19.13 mg/kg respectively. The analysis result in SRM NIST 1646a of the concentration of Al and Na were 2.15 and 0.70% and the concentration of As, Cr, Co, La and Sc were 5.75, 36.3, 4.58, 15.67 and 4.00 mg/kg respectively. These results analysis had relative bias and u-test ranged from 0.4-11.3% and 0.15-2.25. The accuracy and precision evaluation based on International Atomic Energy Agency (IAEA criteria was also applied. The result showed that NAA technique is applicable for the environmental samples analysis, and it also showed that the NAA laboratory in BATAN Bandung has a good performance.   Keywords: NAA, inter-comparison, estuarine sediment, coal fly ash, environmental samples

A Position Sensorless Control Method for SRM Based on Variation of Phase Inductance

Science.gov (United States)

Komatsuzaki, Akitomo; Miki, Ichiro

Switched reluctance motor (SRM) drives are suitable for variable speed industrial applications because of the simple structure and high-speed capability. However, it is necessary to detect the rotor position with a position sensor attached to the motor shaft. The use of the sensor increases the cost of the drive system and machine size, and furthermore the reliability of the system is reduced. Therefore, several approaches to eliminate the position sensor have already been reported. In this paper, a position sensorless control method based on the variation of the phase inductance is described. The phase inductance regularly varies with the rotor position. The SRM is controlled without the position sensor using the de-fluxing period and the phase inductance. The turn-off timing is determined by computing the difference of angle between the sampling point and the aligned point and the variation of angle during the de-fluxing period. In the magnetic saturation region, the phase inductance at the current when the effect of the saturation starts is computed and the sensorless control can be carried out using this inductance. Experimental results show that the SRM is well controlled without the position sensor using the proposed method.

NMR reaction monitoring in flow synthesis.

Science.gov (United States)

Gomez, M Victoria; de la Hoz, Antonio

2017-01-01

Recent advances in the use of flow chemistry with in-line and on-line analysis by NMR are presented. The use of macro- and microreactors, coupled with standard and custom made NMR probes involving microcoils, incorporated into high resolution and benchtop NMR instruments is reviewed. Some recent selected applications have been collected, including synthetic applications, the determination of the kinetic and thermodynamic parameters and reaction optimization, even in single experiments and on the μL scale. Finally, software that allows automatic reaction monitoring and optimization is discussed.

Individual carotenoid content of SRM 1548 total diet and influence of storage temperature, lyophilization, and irradiation on dietary carotenoids

International Nuclear Information System (INIS)

Craft, N.E.; Wise, S.A.

1993-01-01

A modified version of the AOAC procedure for the extraction of carotenoids from mixed feeds was coupled with an isocratic reversed-phase liquid chromatography (LC) method to measure individual carotenoids in SRM 1548 total diet and in a high-carotenoid mixed diet (HCMD). The major carotenoids identified in SRM 1548 were lycopene, beta-carotene, lutein, alpha-carotene, and zeaxanthin in descending order of concentration. The concentration of all carotenoids in SRM 1548 decreased as storage temperature increased. Significant differences in carotenoid concentrations occurred between -80 and 4 degrees C storage temperatures. Lyophilization of the HCMD significantly decreased beta-carotene and lycopene concentrations and produced an apparent increase in xanthophyll concentrations. Exposure to gamma-irradiation significantly decreased alpha-carotene and beta-carotene concentrations and led to an apparent increase in P-cryptoxanthin. SRM 1548 was found to be unsuitable for use as a reference material for carotenoid measurements, while HCMD has greater potential as a reference material

NMR reaction monitoring in flow synthesis

Directory of Open Access Journals (Sweden)

M. Victoria Gomez

2017-02-01

Full Text Available Recent advances in the use of flow chemistry with in-line and on-line analysis by NMR are presented. The use of macro- and microreactors, coupled with standard and custom made NMR probes involving microcoils, incorporated into high resolution and benchtop NMR instruments is reviewed. Some recent selected applications have been collected, including synthetic applications, the determination of the kinetic and thermodynamic parameters and reaction optimization, even in single experiments and on the μL scale. Finally, software that allows automatic reaction monitoring and optimization is discussed.

How well could existing sensors detect the deployment of a solar radiation management (SRM) geoengineering effort?

Energy Technology Data Exchange (ETDEWEB)

Hurd, Alan J. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2016-04-29

While the stated reason for asking this question is “to understand better our ability to warn policy makers in the unlikely event of an unanticipated SRM geoengineering deployment or large-scale field experiment”, my colleagues and I felt that motives would be important context because the scale of any meaningful SRM deployment would be so large that covert deployment seems impossible. However, several motives emerged that suggest a less-than-global effort might be important.

SRM, motor para el desarrollo de la cadena de valor Supplier Relationship Management – SRM gestión de las relaciones con los proveedores

Directory of Open Access Journals (Sweden)

Luis Leonardo Mendoza S.

2010-01-01

Ejemplo de ello es el SRM, Supplier Relationship Management, en donde por medio de la constitución de acuerdos basados en intereses comunes, se establecen relaciones estrechas, funcionales y eficientes entre las partes, permitiendo por esta vía la garantía del suministro, y de esta forma, darle un importante impulso para el desarrollo de la cadena de valor.

Substrate-Coated Illumination Droplet Spray Ionization: Real-Time Monitoring of Photocatalytic Reactions

Science.gov (United States)

Zhang, Hong; Li, Na; Zhao, Dandan; Jiang, Jie; You, Hong

2017-09-01

Real-time monitoring of photocatalytic reactions facilitates the elucidation of the mechanisms of the reactions. However, suitable tools for real-time monitoring are lacking. Herein, a novel method based on droplet spray ionization named substrate-coated illumination droplet spray ionization (SCI-DSI) for direct analysis of photocatalytic reaction solution is reported. SCI-DSI addresses many of the analytical limitations of electrospray ionization (ESI) for analysis of photocatalytic-reaction intermediates, and has potential for both in situ analysis and real-time monitoring of photocatalytic reactions. In SCI-DSI-mass spectrometry (MS), a photocatalytic reaction occurs by loading sample solutions onto the substrate-coated cover slip and by applying UV light above the modified slip; one corner of this slip adjacent to the inlet of a mass spectrometer is the high-electric-field location for launching a charged-droplet spray. After both testing and optimizing the performance of SCI-DSI, the value of this method for in situ analysis and real-time monitoring of photocatalytic reactions was demonstrated by the removal of cyclophosphamide (CP) in TiO2/UV. Reaction times ranged from seconds to minutes, and the proposed reaction intermediates were captured and identified by tandem mass spectrometry. Moreover, the free hydroxyl radical (·OH) was identified as the main radicals for CP removal. These results show that SCI-DSI is suitable for in situ analysis and real-time monitoring of CP removal under TiO2-based photocatalytic reactions. SCI-DSI is also a potential tool for in situ analysis and real-time assessment of the roles of radicals during CP removal under TiO2-based photocatalytic reactions. Graphical Abstract[Figure not available: see fulltext.

Ground To Flight Extrapolation Of SRM Radiative Loads

Science.gov (United States)

Ferrara, V.; Paglia, F.; Mogavero, A.; Genito, M.; Bonnet, M.

2011-05-01

VEGA is a European launch vehicle under development by the Prime Contractor ELV S.p.A. in the frame of an ESA Contract. It is constituted by four stages, dedicated to the scientific/commercial market of small satellites (300 ÷ 2500 kg) into Low Earth Orbits, with inclinations ranging from 5.2° up to Sun Synchronous Orbits and with altitude ranging from 300 to 1500 km. In the framework of the development of the VEGA Launch vehicle a great effort has been spent in the development of all the three SRMs powering the LV. Even if this development is really challenging on the other hand a great amount of experimental data coming from SRM firing tests is available. Taking benefit of the up to date CFD methodology and of the existence of experimental data a verification/validation activity has been performed by Avio S.p.A. and ELV S.p.A., aimed at the estimation of in-flight radiative loads coming from the VEGA Solid Rocket motors. Numerical simulations have been performed by means of the multi-purpose code FLUENT 6.3 ® under the hypothesis of a steady state approach considering a turbulent flow. A multiphase numerical approach has been also developed and validated against experimental data coming from the bench firing tests showing a good level of numerical accuracy (1Fig.1). The study of the Vega motors plume has been identified in the class of dispersed flows, with the typical regime of particulate flow in which has been identified the configuration of solid particles in gas. The selected approach is two way coupled Eulerian-Lagrangian. The Navier-Stokes equations, including source term to take into account the presence of particulate, are solved at each time-step in conjunction with the radiation equation and particulate motion law and heat-transfer equations. The resulting system of equations is a fully coupled system solved with an explicit algorithm. The methodology, and particularly radiation properties settings, has been verified against available experimental

Grid data access on widely distributed worker nodes using Scalla and SRM

Czech Academy of Sciences Publication Activity Database

Jakl, Pavel; Lauret, J.; Hanushevsky, A.; Shoshani, A.; Sim, A.; Gu, J.

2008-01-01

Roč. 119, - (2008), 072019/1-072019/11 ISSN 1742-6588 R&D Projects: GA ČR GA202/07/0079; GA MŠk LC07048 Institutional research plan: CEZ:AV0Z10480505 Keywords : Scalla * SRM * RHIC Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders

Online monitoring of chemical reactions by polarization-induced electrospray ionization.

Science.gov (United States)

Meher, Anil Kumar; Chen, Yu-Chie

2016-09-21

Polarization-induced electrospray ionization (PI-ESI) is a simple technique for instant generation of gas-phase ions directly from a microliter-sized droplet for mass spectrometric analysis. A sample droplet was placed over a dielectric substrate and in proximity (2-3 mm) to the inlet of a mass spectrometer. Owing to the polarization effect induced by the high electric field provided by the mass spectrometer, the droplet was polarized and the electrospray was generated from the apex of the droplet. The polarization-induced electrospray could last for tens of seconds, which was sufficiently long to monitor fast reactions occurring within few seconds. Thus, we demonstrated the feasibility of using the droplet-based PI-ESI MS for the online monitoring of fast reactions by simply mixing two droplets (5-10 μL) containing reactants on a dielectric substrate placed in front of a mass spectrometer applied with a high voltage (-4500 V). Schiff base reactions and oxidation reactions that can generate intermediates/products within a few seconds were selected as the model reactions. The ionic reaction species generated from intermediates and products can be simultaneously monitored by PI-ESI MS in real time. We also used this approach to selectively detect acetone from a urine sample, in which acetone was derivatized in situ. In addition, the possibility of using this approach for quantitative analysis of acetone from urine samples was examined. Copyright © 2016 Elsevier B.V. All rights reserved.

Validity and reproducibility of the ErgomoPro power meter compared with the SRM and Powertap power meters.

Science.gov (United States)

Duc, Sebastien; Villerius, Vincent; Bertucci, William; Grappe, Frederic

2007-09-01

The ErgomoPro (EP) is a power meter that measures power output (PO) during outdoor and indoor cycling via 2 optoelectronic sensors located in the bottom bracket axis. The aim of this study was to determine the validity and the reproducibility of the EP compared with the SRM crank set and Powertap hub (PT). The validity of the EP was tested in the laboratory during 8 submaximal incremental tests (PO: 100 to 400 W), eight 30-min submaximal constant-power tests (PO = 180 W), and 8 sprint tests (PO > 750 W) and in the field during 8 training sessions (time: 181 +/- 73 min; PO: approximately 140 to 160 W). The reproducibility was assessed by calculating the coefficient of PO variation (CV) during the submaximal incremental and constant tests. The EP provided a significantly higher PO than the SRM and PT during the submaximal incremental test: The mean PO differences were +6.3% +/- 2.5% and +11.1% +/- 2.1% respectively. The difference was greater during field training sessions (+12.0% +/- 5.7% and +16.5% +/- 5.9%) but lower during sprint tests (+1.6% +/- 2.5% and +3.2% +/- 2.7%). The reproducibility of the EP is lower than those of the SRM and PT (CV = 4.1% +/- 1.8%, 1.9% +/- 0.4%, and 2.1% +/- 0.8%, respectively). The EP power meter appears less valid and reliable than the SRM and PT systems.

Real time monitoring of accelerated chemical reactions by ultrasonication-assisted spray ionization mass spectrometry.

Science.gov (United States)

Lin, Shu-Hsuan; Lo, Ta-Ju; Kuo, Fang-Yin; Chen, Yu-Chie

2014-01-01

Ultrasonication has been used to accelerate chemical reactions. It would be ideal if ultrasonication-assisted chemical reactions could be monitored by suitable detection tools such as mass spectrometry in real time. It would be helpful to clarify reaction intermediates/products and to have a better understanding of reaction mechanism. In this work, we developed a system for ultrasonication-assisted spray ionization mass spectrometry (UASI-MS) with an ~1.7 MHz ultrasonic transducer to monitor chemical reactions in real time. We demonstrated that simply depositing a sample solution on the MHz-based ultrasonic transducer, which was placed in front of the orifice of a mass spectrometer, the analyte signals can be readily detected by the mass spectrometer. Singly and multiply charged ions from small and large molecules, respectively, can be observed in the UASI mass spectra. Furthermore, the ultrasonic transducer used in the UASI setup accelerates the chemical reactions while being monitored via UASI-MS. The feasibility of using this approach for real-time acceleration/monitoring of chemical reactions was demonstrated. The reactions of Girard T reagent and hydroxylamine with steroids were used as the model reactions. Upon the deposition of reactant solutions on the ultrasonic transducer, the intermediate/product ions are readily generated and instantaneously monitored using MS within 1 s. Additionally, we also showed the possibility of using this reactive UASI-MS approach to assist the confirmation of trace steroids from complex urine samples by monitoring the generation of the product ions. Copyright © 2014 John Wiley & Sons, Ltd.

Agreement of Power Measures between Garmin Vector and SRM Cycle Power Meters

Science.gov (United States)

Novak, Andrew R.; Dascombe, Benjamin J.

2016-01-01

This study aimed to determine if the Garmin Vector (Schaffhausen, Switzerland) power meter produced acceptable measures when compared with the Schoberer Rad Messetechnik (SRM; Julich, Germany) power meter across a range of high-intensity efforts. Twenty-one well-trained cyclists completed power profiles (seven maximal mean efforts between 5 and…

Determination of 21 elements by INAA for certification of SRM 1570a, Spinach

International Nuclear Information System (INIS)

Becker, D.A.

1995-01-01

Analyses for certification have been made by instrumental neutron activation analysis (INAA) for the determination of 21 elements in the National Institute of Standards and technology (NIST) Spinach renewal reference material, SRM 1570a. Elements determined included ones with short halflife products (Al, V, Ca, Mg) intermediate halflife products (Mn, Na, K, La), and long halflife products (Ba, Co, Cr, Cs, Eu, Fe, Rb, Sb, Sc, Se, Sr, Th, and Zn). For the first time a new robotic sample changer was used in the counting of long halflife indicator isotopes for certification of an SRM. Uncertainties obtained averaged ± 1.80% for the four major and minor constituents (Ca, K, Mg, Na); ± 3.14% for elements with concentrations form 1 to 400 mg/kg (Al, Ba, Cr, Fe, Mn, Rb, Sr, and Zn); and ± 8.31% for the ultra trace elements (<1 mg/kg) (Co, Cs, Eu, La, Sb, Sc, Se, Th, and V). (author) 3 refs.; 3 tabs

Crosschecking of alpha particle monitor reactions up to 50 MeV

Energy Technology Data Exchange (ETDEWEB)

Takács, S., E-mail: stakacs@atomki.hu [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Ditrói, F.; Szűcs, Z. [Institute for Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Haba, H.; Komori, Y. [Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan); Aikawa, M. [Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan); Saito, M. [Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Nishina Center for Accelerator-Based Science, RIKEN, Wako 351-0198 (Japan)

2017-04-15

Selected reactions with well-defined excitation functions can be used to monitor the parameters of charged particle beams. The frequently used reactions for monitoring alpha particle beams are the {sup 27}Al(α,x){sup 22,24}Na, {sup nat}Ti(α,x){sup 51}Cr, {sup nat}Cu(α,x){sup 66,67}Ga and {sup nat}Cu(α,x){sup 65}Zn reactions. The excitation functions for these reactions were studied using the activation method and stacked target irradiation technique to crosscheck and to compare the above six reactions. Thin metallic foils with natural isotopic composition and well defined thickness were stacked together in sandwich targets and were irradiated at the AVF cyclotron of RIKEN with an alpha particle beam of 51.2 MeV. The activity of the target foils were assessed by using high-resolution gamma spectrometers of high purity Ge detectors. The data sets of the six processes were crosschecked with each other to provide consistent, cross-linked numerical cross section data.

Optofluidic UV-Vis spectrophotometer for online monitoring of photocatalytic reactions.

Science.gov (United States)

Wang, Ning; Tan, Furui; Zhao, Yu; Tsoi, Chi Chung; Fan, Xudong; Yu, Weixing; Zhang, Xuming

2016-06-29

On-chip integration of optical detection units into the microfluidic systems for online monitoring is highly desirable for many applications and is also well in line with the spirit of optofluidics technology-fusion of optics and microfluidics for advanced functionalities. This paper reports the construction of a UV-Vis spectrophotometer on a microreactor, and demonstrates the online monitoring of the photocatalytic degradations of methylene blue and methyl orange under different flow rates and different pH values by detecting the intensity change and/or the peak shift. The integrated device consists of a TiO2-coated glass substrate, a PDMS micro-sized reaction chamber and two flow cells. By comparing with the results of commercial equipment, we have found that the measuring range and the sensitivity are acceptable, especially when the transmittance is in the range of 0.01-0.9. This integrated optofluidic device can significantly cut down the test time and the sample volume, and would provide a versatile platform for real-time characterization of photochemical performance. Moreover, its online monitoring capability may enable to access the usually hidden information in biochemical reactions like intermediate products, time-dependent processes and reaction kinetics.

Optofluidic UV-Vis spectrophotometer for online monitoring of photocatalytic reactions

Science.gov (United States)

Wang, Ning; Tan, Furui; Zhao, Yu; Tsoi, Chi Chung; Fan, Xudong; Yu, Weixing; Zhang, Xuming

2016-06-01

On-chip integration of optical detection units into the microfluidic systems for online monitoring is highly desirable for many applications and is also well in line with the spirit of optofluidics technology-fusion of optics and microfluidics for advanced functionalities. This paper reports the construction of a UV-Vis spectrophotometer on a microreactor, and demonstrates the online monitoring of the photocatalytic degradations of methylene blue and methyl orange under different flow rates and different pH values by detecting the intensity change and/or the peak shift. The integrated device consists of a TiO2-coated glass substrate, a PDMS micro-sized reaction chamber and two flow cells. By comparing with the results of commercial equipment, we have found that the measuring range and the sensitivity are acceptable, especially when the transmittance is in the range of 0.01-0.9. This integrated optofluidic device can significantly cut down the test time and the sample volume, and would provide a versatile platform for real-time characterization of photochemical performance. Moreover, its online monitoring capability may enable to access the usually hidden information in biochemical reactions like intermediate products, time-dependent processes and reaction kinetics.

Organisational Pattern Driven Recovery Mechanisms

Science.gov (United States)

Giacomo, Valentina Di; Presenza, Domenico; Riccucci, Carlo

The process of reaction to system failures and security attacks is strongly influenced by its infrastructural, procedural and organisational settings. Analysis of reaction procedures and practices from different domains (Air Traffic Management, Response to Computer Security Incident, Response to emergencies, recovery in Chemical Process Industry) highlight three key requirements for this activity: smooth collaboration and coordination among responders, accurate monitoring and management of resources and ability to adapt pre-established reaction plans to the actual context. The SERENITY Reaction Mechanisms (SRM) is the subsystem of the SERENITY Run-time Framework aimed to provide SERENITY aware AmI settings (i.e. socio-technical systems with highly distributed dynamic services) with functionalities to implement applications specific reaction strategies. The SRM uses SERENITY Organisational S&D Patterns as run-time models to drive these three key functionalities.

The automatic radiation monitor distributed System SRM-256C

International Nuclear Information System (INIS)

Stetsenko, G.N.; Rastsvetalov, Y.N.; Yanovich, A.A.

1996-01-01

The Controlled and Supervised Areas (CSA) of UNK proton accelerator built in Protvino (IHEP, Russia), borrows the significant area (more than 15 sq.km). Submitted in work results of accounts show, that by major factors, influencing to a radioecological conditions in region at the expense of work UNK are: 1) the output of pulsing radiation on day-time surface; 2) the radionuclides receipts with drinking water; 3) the pollution of radioactive air from system of ventilation. At normal mode of UNK operation the equivalent dose rates on daytime surface of pulsing radiation will changes in limits from 0.5 mcSv/hours near overmines buildings up to 0.1 mcSv / hour on the CSA border. The average equivalent dose rates per year due to internal irradiation at use (intakes) of drinking water will not exceed 5 - 50 mcSv/years. The Maximum equivalent dose rates on day-time surface, caused by pollution of radioactive air does not exceed 0.01... 0.03 mcSv/hour in limits of CSA, and the average equivalent dose per year caused by internal irradiation does not exceed 0.05 mcSv/years. At emergency-free operation the maximum degree of the UNK influence in limits of CSA is estimated in terms of average equivalent dose per year at levels, not exceeding 0.05... 0.10 mSv/year. For maintenance of integral environmental monitoring of total external radiation levels in limits of CSA network of passive monitor stations will be developed

NBS SRM 1569 Brewer's Yeast: Is it an adequate standard reference material for testing a chromium determination in biological materials tion in biological materials

International Nuclear Information System (INIS)

Goeij, J.J.M. de; Volkers, K.J.; Tjioe, P.S.; Kroon, J.J.

1978-01-01

Some analytical experiences with NBS SRM 1569 Brewer's Yeast are presented. Against this background the adequacy of this standard reference material for the determination of chromium in biological materials is discussed. Authors have three main objections. Due to its high content of insoluble chromium-containing particles, SRM 1569 is not typical for biological materials, possibly not even for Brewer's Yeast. The chromium level of SRM 1569 is not typical for the chromium levels normally encountered in pure biological materials. The major fraction (69 +- 3 percent) of the chromium is present in a form which is insoluble under the conditions used in Author's analysis. (T.I.)

Improving iodine homogeneity in NIST SRM 1548a Typical Diet by cryogenic grinding

Czech Academy of Sciences Publication Activity Database

Kučera, Jan; Kameník, Jan

2015-01-01

Roč. 20, č. 3 (2015), s. 189-194 ISSN 0949-1775 R&D Projects: GA ČR(CZ) GBP108/12/G108; GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : Iodine * reference material * NIST SRM 1548a * cryogenic grinding * homogeneity Subject RIV: CB - Analytical Chemistry, Separation Impact factor: 1.010, year: 2015

Cold Flow Determination of the Internal Flow Environment Around the Submerged TVC Nozzle for the Space Shuttle SRM

Science.gov (United States)

Whitesides, R. H.; Ghosh, A.; Jenkins, S. L.; Bacchus, D. L.

1989-01-01

A series of subscale cold flow tests was performed to quantify the gas flow characteristics at the aft end of the Space Shuttle Solid Rocket Motor. This information was used to support the analyses of the redesigned nozzle/case joint. A portion of the thermal loads at the joint are due to the circumferential velocities and pressure gradients caused primarily by the gimbaling of the submerged nose TVC nozzle. When the nozzle centerline is vectored with respect to the motor centerline, asymmetries are set up in the flow field under the submerged nozzle and immediately adjacent to the nozzle/case joint. Specific program objectives included: determination of the effects of nozzle gimbal angle and propellant geometry on the circumferential flow field; measurement of the static pressure and gas velocities in the vicinity of the nozzle/case joint; use of scaling laws to apply the subscale cold flow data to the full scale SRM; and generation of data for use in validation of 3-D computational fluid dynamic, CFD, models of the SRM flow field. These tests were conducted in the NASA Marshall Space Flight Center Airflow Facility with a 7.5 percent scale model of the aft segment of the SRM. Static and dynamic pressures were measured in the model to quantify the flow field. Oil flow data was also acquired to obtain qualitative visual descriptions of the flow field. Nozzle gimbal angles of 0, 3.5, and 7 deg were used with propellant grain configurations corresponding to motor burn times of 0, 9, 19, and 114 seconds. This experimental program was successful in generating velocity and pressure gradient data for the flow field around the submerged nose nozzle of the Space Shuttle SRM at various burn times and gimbal angles. The nature of the flow field adjacent to the nozzle/case joint was determined with oil droplet streaks, and the velocity and pressure gradients were quantified with pitot probes and wall static pressure measurements. The data was applied to the full scale SRM thru

Ablation characteristics and reaction mechanism of insulation materials under slag deposition condition

Science.gov (United States)

Guan, Yiwen; Li, Jiang; Liu, Yang

2017-07-01

Current understanding of the physical and chemical processes involved in the ablation of insulation materials by highly aluminized solid propellants is limited. The study on the heat transfer and ablation principle of ethylene propylene diene monomer (EPDM) materials under slag deposition condition is essential for future design or modification of large solid rocket motors (SRMs) for launch application. In this paper, the alumina liquid flow pattern and the deposition principle in full-scale SRM engines are discussed. The interaction mechanism between the alumina droplets and the wall are analyzed. Then, an experimental method was developed to simulate the insulation material ablation under slag deposition condition. Experimental study was conducted based on a laboratory-scale device. Meanwhile, from the analysis of the cross-sectional morphology and chemical composition of the charring layer after ablation, the reaction mechanism of the charring layer under deposition condition was discussed, and the main reaction equation was derived. The numerical simulation and experimental results show the following. (i) The alumina droplet flow in the deposition section of the laboratory-scale device is similar to that of a full-scale SRM. (ii) The charring layer of the EPDM insulator displays a porous tight/loose structure under high-temperature slag deposition condition. (iii) A seven-step carbothermal reduction in the alumina is derived and established under high-pressure and high-temperature environment in the SRM combustion chamber. (iv) The analysis using thermodynamic software indicates that the reaction of the alumina and charring layer initially forms Al4C3 during the operation. Then, Al element and Al2OC compound are subsequently produced with the reduction in the release of gas CO as well with continuous environmental heating.

Monitoring biodiesel reactions of soybean oil and sunflower oil using ultrasonic parameters

International Nuclear Information System (INIS)

Figueiredo, M K K; Silva, C E R; Alvarenga, A V; Costa-Félix, R P B

2015-01-01

Biodiesel is an innovation that attempts to substitute diesel oil with biomass. The aim of this paper is to show the development of a real-time method to monitor transesterification reactions by using low-power ultrasound and pulse/echo techniques. The results showed that it is possible to identify different events during the transesterification process by using the proposed parameters, showing that the proposed method is a feasible way to monitor the reactions of biodiesel during its fabrication, in real time, and with relatively low- cost equipment

Monitoring biodiesel reactions of soybean oil and sunflower oil using ultrasonic parameters

Science.gov (United States)

Figueiredo, M. K. K.; Silva, C. E. R.; Alvarenga, A. V.; Costa-Félix, R. P. B.

2015-01-01

Biodiesel is an innovation that attempts to substitute diesel oil with biomass. The aim of this paper is to show the development of a real-time method to monitor transesterification reactions by using low-power ultrasound and pulse/echo techniques. The results showed that it is possible to identify different events during the transesterification process by using the proposed parameters, showing that the proposed method is a feasible way to monitor the reactions of biodiesel during its fabrication, in real time, and with relatively low- cost equipment.

In Situ Monitoring of Chemical Reactions at a Solid-Water Interface by Femtosecond Acoustics.

Science.gov (United States)

Shen, Chih-Chiang; Weng, Meng-Yu; Sheu, Jinn-Kong; Yao, Yi-Ting; Sun, Chi-Kuang

2017-11-02

Chemical reactions at a solid-liquid interface are of fundamental importance. Interfacial chemical reactions occur not only at the very interface but also in the subsurface area, while existing monitoring techniques either provide limited spatial resolution or are applicable only for the outmost atomic layer. Here, with the aid of the time-domain analysis with femtosecond acoustics, we demonstrate a subatomic-level-resolution technique to longitudinally monitor chemical reactions at solid-water interfaces, capable of in situ monitoring even the subsurface area under atmospheric conditions. Our work was proven by monitoring the already-known anode oxidation process occurring during photoelectrochemical water splitting. Furthermore, whenever the oxide layer thickness equals an integer  number of the effective atomic layer thickness, the measured acoustic echo will show higher signal-to-noise ratios with reduced speckle noise, indicating the quantum-like behavior of this coherent-phonon-based technique.

ALPHA SPECTROMETRIC EVALUATION OF SRM-995 AS A POTENTIAL URANIUM/THORIUM DOUBLE TRACER SYSTEM FOR AGE-DATING URANIUM MATERIALS

Energy Technology Data Exchange (ETDEWEB)

Beals, D.

2011-12-06

Uranium-233 (t{sub 1/2} {approx} 1.59E5 years) is an artificial, fissile isotope of uranium that has significant importance in nuclear forensics. The isotope provides a unique signature in determining the origin and provenance of uranium-bearing materials and is valuable as a mass spectrometric tracer. Alpha spectrometry was employed in the critical evaluation of a {sup 233}U standard reference material (SRM-995) as a dual tracer system based on the in-growth of {sup 229}Th (t{sub 1/2} {approx} 7.34E3 years) for {approx}35 years following radiochemical purification. Preliminary investigations focused on the isotopic analysis of standards and unmodified fractions of SRM-995; all samples were separated and purified using a multi-column anion-exchange scheme. The {sup 229}Th/{sup 233}U atom ratio for SRM-995 was found to be 1.598E-4 ({+-} 4.50%) using recovery-corrected radiochemical methods. Using the Bateman equations and relevant half-lives, this ratio reflects a material that was purified {approx} 36.8 years prior to this analysis. The calculated age is discussed in contrast with both the date of certification and the recorded date of last purification.

In-situ nanoelectrospray for high-throughput screening of enzymes and real-time monitoring of reactions.

Science.gov (United States)

Yang, Yuhan; Han, Feifei; Ouyang, Jin; Zhao, Yunling; Han, Juan; Na, Na

2016-01-01

The in-situ and high-throughput evaluation of enzymes and real-time monitoring of enzyme catalyzed reactions in liquid phase is quite significant in the catalysis industry. In-situ nanoelectrospray, the direct sampling and ionization method for mass spectrometry, has been applied for high-throughput evaluation of enzymes, as well as the on-line monitoring of reactions. Simply inserting a capillary into a liquid system with high-voltage applied, analytes in liquid reaction system can be directly ionized at the capillary tip with small volume consumption. With no sample pre-treatment or injection procedure, different analytes such as saccharides, amino acids, alkaloids, peptides and proteins can be rapidly and directly extracted from liquid phase and ionized at the capillary tip. Taking irreversible transesterification reaction of vinyl acetate and ethanol as an example, this technique has been used for the high-throughput evaluation of enzymes, fast optimizations, as well as real-time monitoring of reaction catalyzed by different enzymes. In addition, it is even softer than traditional electrospray ionization. The present method can also be used for the monitoring of other homogenous and heterogeneous reactions in liquid phases, which will show potentials in the catalysis industry. Copyright © 2015 Elsevier B.V. All rights reserved.

Targeted proteomics as a tool for porcine acute phase proteins measurements

DEFF Research Database (Denmark)

Marco-Ramell, Anna; Bassols, Anna; Bislev, Stine Lønnerup

2013-01-01

. Selected reaction monitoring (SRM), a targeted quantitative proteomic technique, may be used as an alternative to commercial kits for the measurement and validation of target proteins. Acute phase proteins (APPs) are widely recognized inflammation and infection biomarkers (Eckersall, 2010...

Protein biomarker discovery and fast monitoring for the identification and detection of Anisakids by parallel reaction monitoring (PRM) mass spectrometry.

Science.gov (United States)

Carrera, Mónica; Gallardo, José M; Pascual, Santiago; González, Ángel F; Medina, Isabel

2016-06-16

Anisakids are fish-borne parasites that are responsible for a large number of human infections and allergic reactions around the world. World health organizations and food safety authorities aim to control and prevent this emerging health problem. In the present work, a new method for the fast monitoring of these parasites is described. The strategy is divided in three steps: (i) purification of thermostable proteins from fish-borne parasites (Anisakids), (ii) in-solution HIFU trypsin digestion and (iii) monitoring of several peptide markers by parallel reaction monitoring (PRM) mass spectrometry. This methodology allows the fast detection of Anisakids in Biomarker Discovery and the Fast Monitoring for the identification and detection of Anisakids in fishery products. The strategy is based on the purification of thermostable proteins, the use of accelerated in-solution trypsin digestions under an ultrasonic field provided by High-Intensity Focused Ultrasound (HIFU) and the monitoring of several peptide biomarkers by Parallel Reaction Monitoring (PRM) Mass Spectrometry in a linear ion trap mass spectrometer. The workflow allows the unequivocal detection of Anisakids, in <2h. The present strategy constitutes the fastest method for Anisakids detection, whose application in the food quality control area, could provide to the authorities an effective and rapid method to guarantee the safety to the consumers. Copyright © 2016 Elsevier B.V. All rights reserved.

A Sensor-less Method for Online Thermal Monitoring of Switched Reluctance Machine

DEFF Research Database (Denmark)

Wang, Chao; Liu, Hui; Liu, Xiao

2015-01-01

Stator winding is one of the most vulnerable parts in Switched Reluctance Machine (SRM), especially under thermal stresses during frequently changing operation circumstances and susceptible heat dissipation conditions. Thus real-time online thermal monitoring of the stator winding is of great sig...

Deep-Dive Targeted Quantification for Ultrasensitive Analysis of Proteins in Nondepleted Human Blood Plasma/Serum and Tissues

Energy Technology Data Exchange (ETDEWEB)

Nie, Song [Biological Sciences Division; Shi, Tujin [Biological Sciences Division; Fillmore, Thomas L. [Biological Sciences Division; Schepmoes, Athena A. [Biological Sciences Division; Brewer, Heather [Biological Sciences Division; Gao, Yuqian [Biological Sciences Division; Song, Ehwang [Biological Sciences Division; Wang, Hui [Biological Sciences Division; Rodland, Karin D. [Biological Sciences Division; Qian, Wei-Jun [Biological Sciences Division; Smith, Richard D. [Biological Sciences Division; Liu, Tao [Biological Sciences Division

2017-08-11

Mass spectrometry-based targeted proteomics (e.g., selected reaction monitoring, SRM) is emerging as an attractive alternative to immunoassays for protein quantification. Recently we have made significant progress in SRM sensitivity for enabling quantification of low ng/mL to sub-ng/mL level proteins in nondepleted human blood plasma/serum without affinity enrichment. However, precise quantification of extremely low abundant but biologically important proteins (e.g., ≤100 pg/mL in blood plasma/serum) using targeted proteomics approaches still remains challenging. To address this need, we have developed an antibody-independent Deep-Dive SRM (DD-SRM) approach that capitalizes on multidimensional high-resolution reversed-phase liquid chromatography (LC) separation for target peptide enrichment combined with precise selection of target peptide fractions of interest, significantly improving SRM sensitivity by ~5 orders of magnitude when compared to conventional LC-SRM. Application of DD-SRM to human serum and tissue has been demonstrated to enable precise quantification of endogenous proteins at ~10 pg/mL level in nondepleted serum and at <10 copies per cell level in tissue. Thus, DD-SRM holds great promise for precisely measuring extremely low abundance proteins or protein modifications, especially when high-quality antibody is not available.

Monitoring chemical reactions by low-field benchtop NMR at 45 MHz: pros and cons.

Science.gov (United States)

Silva Elipe, Maria Victoria; Milburn, Robert R

2016-06-01

Monitoring chemical reactions is the key to controlling chemical processes where NMR can provide support. High-field NMR gives detailed structural information on chemical compounds and reactions; however, it is expensive and complex to operate. Conversely, low-field NMR instruments are simple and relatively inexpensive alternatives. While low-field NMR does not provide the detailed information as the high-field instruments as a result of their smaller chemical shift dispersion and the complex secondary coupling, it remains of practical value as a process analytical technology (PAT) tool and is complimentary to other established methods, such as ReactIR and Raman spectroscopy. We have tested a picoSpin-45 (currently under ThermoFisher Scientific) benchtop NMR instrument to monitor three types of reactions by 1D (1) H NMR: a Fischer esterification, a Suzuki cross-coupling, and the formation of an oxime. The Fischer esterification is a relatively simple reaction run at high concentration and served as proof of concept. The Suzuki coupling is an example of a more complex, commonly used reaction involving overlapping signals. Finally, the oxime formation involved a reaction in two phases that cannot be monitored by other PAT tools. Here, we discuss the pros and cons of monitoring these reactions at a low-field of 45 MHz by 1D (1) H NMR. Copyright © 2015 John Wiley & Sons, Ltd. Copyright © 2015 John Wiley & Sons, Ltd.

Monitoring Acidophilic Microbes with Real-Time Polymerase Chain Reaction (PCR) Assays

Energy Technology Data Exchange (ETDEWEB)

Frank F. Roberto

2008-08-01

Many techniques that are used to characterize and monitor microbial populations associated with sulfide mineral bioleaching require the cultivation of the organisms on solid or liquid media. Chemolithotrophic species, such as Acidithiobacillus ferrooxidans and Leptospirillum ferrooxidans, or thermophilic chemolithotrophs, such as Acidianus brierleyi and Sulfolobus solfataricus can grow quite slowly, requiring weeks to complete efforts to identify and quantify these microbes associated with bioleach samples. Real-time PCR (polymerase chain reaction) assays in which DNA targets are amplified in the presence of fluorescent oligonucleotide primers, allowing the monitoring and quantification of the amplification reactions as they progress, provide a means of rapidly detecting the presence of microbial species of interest, and their relative abundance in a sample. This presentation will describe the design and use of such assays to monitor acidophilic microbes in the environment and in bioleaching operations. These assays provide results within 2-3 hours, and can detect less than 100 individual microbial cells.

Method of exchanging cables of neutron monitoring instrumentation tube and folding device of the cable

International Nuclear Information System (INIS)

Sakamaki, Kazuo.

1990-01-01

In a BWR type reactor, a wide range monitor (WRNM) is used instead of a conventional neutron source range monitor (SRM) or an intermediate range monitor (IRM). The WRNM is always fixed to a predetermined position in a reactor core while containing a detection section in a dry tube, different from a conventional monitor. Accordingly, driving devices for the conventional detection section such as in SRM and IRM are not necessary but, when the reactor is operated for a long period of time, it is sometimes necessary to be replaced with new WRNM. According to the present invention, the cable of the detector placed in a neutron instrumentation tube is connected to a cable take-up drum in a take-up device passing through a cask. Then, the cable is taken-up by driving the take-up drum by a driving motor and the WRNM detection section attached to the top end of the cable is contained in the cask. With this constitution, replacing and processing operation for the detection section can be facilitated and operator's exposure dose can be reduced. (I.S.)

System and process for pulsed multiple reaction monitoring

Science.gov (United States)

Belov, Mikhail E

2013-05-17

A new pulsed multiple reaction monitoring process and system are disclosed that uses a pulsed ion injection mode for use in conjunction with triple-quadrupole instruments. The pulsed injection mode approach reduces background ion noise at the detector, increases amplitude of the ion signal, and includes a unity duty cycle that provides a significant sensitivity increase for reliable quantitation of proteins/peptides present at attomole levels in highly complex biological mixtures.

Monitoring emulsion homopolymerization reactions using FT-Raman spectroscopy

Directory of Open Access Journals (Sweden)

M. M. Reis

2005-03-01

Full Text Available The present work describes a methodology for estimation of monomer concentration during homopolymerization reactions by Raman spectroscopy. The estimation is done using linear models based on two different approaches: a univariate approach and a multivariate approach (with principal component regression, PCR, or partial least squares regression, PLS. The linear models are fitted with data from spectra collected from synthetic samples, i.e., samples prepared by dispersing a known concentration of monomer in polymer emulsions. Homopolymerizations of butyl acrylate and of vinyl acetate were monitored by collecting samples from the reactor, and results show that the methodology is efficient for the model fitting and that Raman spectroscopy is a promising technique for on-line monitoring of the emulsion polymerization process.

Analysis of charged particle induced reactions for beam monitor applications

Energy Technology Data Exchange (ETDEWEB)

Surendra Babu, K. [IOP, Academia Sinica, Taipe, Taiwan (China); Lee, Young-Ouk [Nuclear Data Evaluation Laboratory, Korea Atomic Energy Research Institute (Korea, Republic of); Mukherjee, S., E-mail: smukherjee_msuphy@yahoo.co.in [Department of Physics, Faculty of Science, M.S. University of Baroda, Vadodara 390 002 (India)

2012-07-15

The reaction cross sections for different residual nuclides produced in the charged particle (p, d, {sup 3}He and {alpha}) induced reactions were calculated and compared with the existing experimental data which are important for beam monitoring and medical diagnostic applications. A detailed literature compilation and comparison were made on the available data sets for the above reactions. These calculations were carried out using the statistical model code TALYS up to 100 MeV, which contains Kalbach's latest systematic for the emission of complex particles and complex particle-induced reactions. All optical model calculations were performed by ECIS-03, which is built into TALYS. The level density, optical model potential parameters were adjusted to get the better description of experimental data. Various pre-equilibrium models were used in the present calculations with default parameters.

Method of reactor fueling

International Nuclear Information System (INIS)

Saito, Toshiro.

1983-01-01

Purpose: To decrease the cost and shorten the working time by saving fueling neutron detectors and their components. Method: Incore drive tubes for the neutron source range monitor (SRM) and intermediate range monitor (IRM) are disposed respectively within in a reactor core and a SRM detector assembly is inserted to the IRM incore drive tube which is most nearest to the neutron source upon reactor fueling. The reactor core reactivity is monitored by the SRM detector assembly. The SRM detector asesembly inserted into the IRM drive tube is extracted at the time of charging fuels up to the frame connecting the SRM and, thereafter, IRM detection assembly is inserted into the IRM drive tube and the SRM detector assembly is inserted into the SRM drive tube respectively for monitoring the reactor core. (Sekiya, K.)

Adaptação transcultural da versão brasileira da escala Social Rhythm Metric-17 (SRM-17 para a população angolana Cross-cultural adaptation of the Brazilian version of the Social Rhythm Metric-17 (SRM-17 for the population of Angola

Directory of Open Access Journals (Sweden)

Regina Lopes Schimitt

2011-01-01

Full Text Available INTRODUÇÃO: O ritmo social é um conceito que integra a relação entre Zeitgebers (sincronizadores sociais e os marcadores de tempo endógenos, e pode ser avaliado com a Escala de Ritmo Social (Social Rhythm Metric-17, SRM-17. O objetivo deste estudo foi realizar a adaptação da versão brasileira da SRM-17 para o português angolano, comparando as duas escalas em populações que utilizam o mesmo idioma mas apresentam diferenças culturais. MÉTODOS: A versão brasileira da SRM-17 foi submetida à avaliação de 10 estudantes universitários angolanos, que analisaram o grau de clareza de cada um dos 15 itens do instrumento usando uma escala visual analógica de 10 cm e propuseram modificações ao texto. Foi realizada revisão dos resultados para a elaboração da versão final, bem como prova de leitura e relatório final. RESULTADOS: A versão final angolana manteve uma equivalência de itens com relação à versão em português brasileiro. A versão avaliada demonstrou um grau satisfatório de clareza e equivalência semântica na maioria dos itens. Porém, alguns itens apresentaram um escore na clareza inferior à média aritmética de compreensão global do instrumento (8,38±1,0. CONCLUSÃO: Apesar de o português ser o idioma oficial nos dois países, há diferenças culturais significativas nas duas populações. Este trabalho apresenta uma versão adaptada à realidade angolana de um instrumento específico para aferir ritmo social. O processo de adaptação transcultural deve efetivar-se com estudos de validação do instrumento final em uma amostra maior da população, onde também poderão ser avaliadas as equivalências operacional, de medida e funcional.INTRODUCTION: Social rhythm is a concept that correlates social Zeitgebers (synchronizers with endogenous markers of time, and can be assessed with the Social Rhythm Metric-17 (SRM-17. The aim of this study was to adapt the Brazilian version of the SRM-17 to Angolan

Mining the human urine proteome for monitoring renal transplant injury

Energy Technology Data Exchange (ETDEWEB)

Sigdel, Tara K.; Gao, Yuqian; He, Jintang; Wang, Anyou; Nicora, Carrie D.; Fillmore, Thomas L.; Shi, Tujin; Webb-Robertson, Bobbie-Jo; Smith, Richard D.; Qian, Wei-Jun; Salvatierra, Oscar; Camp, David G.; Sarwal, Minnie M.

2016-06-01

The human urinary proteome reflects systemic and inherent renal injury perturbations and can be analyzed to harness specific biomarkers for different kidney transplant injury states. 396 unique urine samples were collected contemporaneously with an allograft biopsy from 396 unique kidney transplant recipients. Centralized, blinded histology on the graft was used to classify matched urine samples into categories of acute rejection (AR), chronic allograft nephropathy (CAN), BK virus nephritis (BKVN), and stable graft (STA). Liquid chromatography–mass spectrometry (LC-MS) based proteomics using iTRAQ based discovery (n=108) and global label-free LC-MS analyses of individual samples (n=137) for quantitative proteome assessment were used in the discovery step. Selected reaction monitoring (SRM) was applied to identify and validate minimal urine protein/peptide biomarkers to accurately segregate organ injury causation and pathology on unique urine samples (n=151). A total of 958 proteins were initially quantified by iTRAQ, 87% of which were also identified among 1574 urine proteins detected in LC-MS validation. 103 urine proteins were significantly (p<0.05) perturbed in injury and enriched for humoral immunity, complement activation, and lymphocyte trafficking. A set of 131 peptides corresponding to 78 proteins were assessed by SRM for their significance in an independent sample cohort. A minimal set of 35 peptides mapping to 33 proteins, were modeled to segregate different injury groups (AUC =93% for AR, 99% for CAN, 83% for BKVN). Urinary proteome discovery and targeted validation identified urine protein fingerprints for non-invasive differentiation of kidney transplant injuries, thus opening the door for personalized immune risk assessment and therapy.

Identification and quantification of cardiac glycosides in blood and urine samples by HPLC/MS/MS.

Science.gov (United States)

Guan, F; Ishii, A; Seno, H; Watanabe-Suzuki, K; Kumazawa, T; Suzuki, O

1999-09-15

Cardiac glycosides (CG) are of forensic importance because of their toxicity and the fact that very limited methods are available for identification of CG in biological samples. In this study, we have developed an identification and quantification method for digoxin, digitoxin, deslanoside, digoxigenin, and digitoxigenin by high-performance liquid chromatography tandem mass spectrometry (HPLC/MS/MS). CG formed abundant [M + NH4]+ ions and much less abundant [M + H]+ ions as observed with electrospray ionization (ESI) source and ammonium formate buffer. Under mild conditions for collision-induced dissociation (CID), each [M + NH4]+ ion fragmented to produce a dominant daughter ion, which was essential to the sensitive method of selected reaction monitoring (SRM) quantification of CG achieved in this study. SRM was compared with selected ion monitoring (SIM) regarding the effects of sample matrixes on the methodology. SRM produced lower detection limits with biological samples than SIM, while both methods produced equal detection limits with CG standards. On the basis of the HPLC/MS/MS results for CG, we have proposed some generalized points for conducting sensitive SRM measurements, in view of the property of analytes as well as instrumental conditions such as the type of HPLC/MS interface and CID parameters. Analytes of which the molecular ion can produce one abundant daughter ion with high yield under CID conditions may be sensitively measured by SRM. ESI is the most soft ionization source developed so far and can afford formation of the fragile molecular ions that are necessary for sensitive SRM detection. Mild CID conditions such as low collision energy and low pressure of collision gas favor production of an abundant daughter ion that is essential to sensitive SRM detection. This knowledge may provide some guidelines for conducting sensitive SRM measurements of very low concentrations of drugs or toxicants in biological samples.

Some issues for blast from a structural reactive material solid

Science.gov (United States)

Zhang, F.

2018-03-01

Structural reactive material (SRM) is consolidated from a mixture of micro- or nanometric reactive metals and metal compounds to the mixture theoretical maximum density. An SRM can thus possess a higher energy density, relying on various exothermic reactions, and higher mechanical strength and heat resistance than that of conventional CHNO explosives. Progress in SRM solid studies is reviewed specifically as an energy source for air blast through the reaction of fine SRM fragments under explosive loading. This includes a baseline SRM solid explosion characterization, material properties of an SRM solid, and its dynamic fine fragmentation mechanisms and fragment reaction mechanisms. The overview is portrayed mainly from the author's own experimental studies combined with theoretical and numerical explanation. These advances have laid down some fundamentals for the next stage of developments.

Overcoming interference with the detection of a stable isotopically labeled microtracer in the evaluation of beclabuvir absolute bioavailability using a concomitant microtracer approach.

Science.gov (United States)

Jiang, Hao; Titsch, Craig; Zeng, Jianing; Jones, Barry; Joyce, Philip; Gandhi, Yash; Turley, Wesley; Burrell, Richard; Aubry, Anne F; Arnold, Mark E

2017-09-05

The oral absolute bioavailability of beclabuvir in healthy subjects was determined using a microdose (100μg) of the stable isotopically labeled tracer via intravenous (IV) infusion started after oral dosing of beclabuvir (150mg). To simultaneously analyze the concentrations of the IV microtracer ([ 13 C 6 ]beclabuvir) and beclabuvir in plasma samples, a liquid chromatography-triple quadrupole mass spectrometry (LC-MS/MS) method was initially developed. Surprisingly beclabuvir significantly interfered with the IV microtracer detection when using the selected reaction monitoring (SRM) in the assay. An interfering component from the drug substance was observed using a high resolution mass spectrometer (HRMS). The mass-to-charge (m/z) of the interfering component was -32ppm different from the nominal value for the IV microtracer and thus could not be differentiated in the SRM assay by the unit mass resolution. To overcome this interference, we evaluated two approaches by either monitoring an alternative product ion using the SRM assay or isolating the interfering component using the parallel reaction monitoring (PRM) assay on the HRMS. This case study has demonstrated two practical approaches for overcoming interferences with the detection of stable isotopically labeled IV microtracers in the evaluation of absolute bioavailability, which provides users the flexibility in using either LC-MS/MS or HRMS to mitigate unpredicted interferences in the assay to support microtracer absolute bioavailability studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Status report on cross-sections of monitor reactions for radioisotope production

International Nuclear Information System (INIS)

Schwerer, O.; Okamoto, K.

1989-12-01

The status of data on cross-sections of 19 monitor reactions, especially for cyclotron operation, is summarized. Most of the information was extracted from the data compiled in EXFOR (EXchange FORmat) which is a common format used by the co-operating nuclear data centres in the world. The EXFOR data were supplemented by a number of additional data sets found in the literature. For each reaction a brief status summary, graphical plots of the available experimental and evaluated data, and a table of all experimental data sorted by incident particle energy, are given

The Validation of AAN Method Used by Rock Sample SRM 2780

International Nuclear Information System (INIS)

Rina Mulyaningsih, Th.

2004-01-01

AAN methods is a non standard testing method. The testing laboratory must be validate its using method to ensure and confirm that it is suitable with application. The analysis of SRM 2780 Hard rock mine waste with 9 replicates has been done to test the accuracy of AAN methods. The result showed that the elements As, Ba, Mn, V, Zn and Na have good accuration were evaluated against the acceptance criteria for accuracy with confidence level 95 %. The elements As, Co, Sc, Cr, Ba, Sb, Cs, Mn, V, Au, Zn and Na have low relative bias between the analyst's value and the target value. The continued testing must be done to test the accuracy of another certificated elements. (author)

Neutron flux monitoring device

International Nuclear Information System (INIS)

Goto, Yasushi; Mitsubori, Minehisa; Ohashi, Kazunori.

1997-01-01

The present invention provides a neutron flux monitoring device for preventing occurrence of erroneous reactor scram caused by the elevation of the indication of a start region monitor (SRM) due to a factor different from actual increase of neutron fluxes. Namely, judgement based on measured values obtained by a pulse counting method and a judgment based on measured values obtained by a Cambel method are combined. A logic of switching neutron flux measuring method to be used for monitoring, namely, switching to an intermediate region when both of the judgements are valid is adopted. Then, even if the indication value is elevated based on the Cambel method with no increase of the counter rate in a neutron source region, the switching to the intermediate region is not conducted. As a result, erroneous reactor scram such as 'shorter reactor period' can be avoided. (I.S.)

A Complementary Vision Strategy for Autonomous Robots in Underground Terrains using SRM and Entropy Models

Directory of Open Access Journals (Sweden)

Omowunmi Isafiade

2013-09-01

Full Text Available This work investigates robots' perception in underground terrains (mines and tunnels using statistical region merging (SRM and the entropy models. A probabilistic approach based on the local entropy is employed. The entropy is measured within a fixed window on a stream of mine and tunnel frames to compute features used in the segmentation process, while SRM reconstructs the main structural components of an imagery by a simple but effective statistical analysis. An investigation is conducted on different regions of the mine, such as the shaft, stope and gallery, using publicly available mine frames, with a stream of locally captured mine images. Furthermore, an investigation is also conducted on a stream of dynamic underground tunnel image frames, using the XBOX Kinect 3D sensors. The Kinect sensors produce streams of red, green and blue (RGB and depth images of 640 × 480 resolution at 30 frames per second. Integrating the depth information into drivability gives a strong cue to the analysis, which detects 3D results augmenting drivable and non-drivable regions in 2D. The results of the 2D and 3D experiment with different terrains, mines and tunnels, together with the qualitative and quantitative evaluations, reveal that a good drivable region can be detected in dynamic underground terrains.

Grid Data Access on Widely Distributed Worker Nodes Using Scalla and SRM

International Nuclear Information System (INIS)

Jakl, Pavel; Lauret, Jerome; Hanushevsky, Andrew; Shoshani, Arie; Sim, Alex; Gu, Junmin

2011-01-01

Facing the reality of storage economics, NP experiments such as RHIC/STAR have been engaged in a shift of the analysis model, and now heavily rely on using cheap disks attached to processing nodes, as such a model is extremely beneficial over expensive centralized storage. Additionally, exploiting storage aggregates with enhanced distributed computing capabilities such as dynamic space allocation (lifetime of spaces), file management on shared storages (lifetime of files, pinning file), storage policies or a uniform access to heterogeneous storage solutions is not an easy task. The Xrootd/Scalla system allows for storage aggregation. We will present an overview of the largest deployment of Scalla (Structured Cluster Architecture for Low Latency Access) in the world spanning over 1000 CPUs co-sharing the 350 TB Storage Elements and the experience on how to make such a model work in the RHIC/STAR standard analysis framework. We will explain the key features and approach on how to make access to mass storage (HPSS) possible in such a large deployment context. Furthermore, we will give an overview of a fully 'gridified' solution using the plug-and-play features of Scalla architecture, replacing standard storage access with grid middleware SRM (Storage Resource Manager) components designed for space management and will compare the solution with the standard Scalla approach in use in STAR for the past 2 years. Integration details, future plans and status of development will be explained in the area of best transfer strategy between multiple-choice data pools and best placement with respect of load balancing and interoperability with other SRM aware tools or implementations.

Grid data access on widely distributed worker nodes using scalla and SRM

International Nuclear Information System (INIS)

Jakl, P; Lauret, J; Hanushevsky, A; Shoshani, A; Sim, A; Gu, J

2008-01-01

Facing the reality of storage economics, NP experiments such as RHIC/STAR have been engaged in a shift of the analysis model, and now heavily rely on using cheap disks attached to processing nodes, as such a model is extremely beneficial over expensive centralized storage. Additionally, exploiting storage aggregates with enhanced distributed computing capabilities such as dynamic space allocation (lifetime of spaces), file management on shared storages (lifetime of files, pinning file), storage policies or a uniform access to heterogeneous storage solutions is not an easy task. The Xrootd/Scalla system allows for storage aggregation. We will present an overview of the largest deployment of Scalla (Structured Cluster Architecture for Low Latency Access) in the world spanning over 1000 CPUs co-sharing the 350 TB Storage Elements and the experience on how to make such a model work in the RHIC/STAR standard analysis framework. We will explain the key features and approach on how to make access to mass storage (HPSS) possible in such a large deployment context. Furthermore, we will give an overview of a fully 'gridified' solution using the plug-and-play features of Scalla architecture, replacing standard storage access with grid middleware SRM (Storage Resource Manager) components designed for space management and will compare the solution with the standard Scalla approach in use in STAR for the past 2 years. Integration details, future plans and status of development will be explained in the area of best transfer strategy between multiple-choice data pools and best placement with respect of load balancing and interoperability with other SRM aware tools or implementations

Grid Data Access on Widely Distributed Worker Nodes Using Scalla and SRM

Energy Technology Data Exchange (ETDEWEB)

Jakl, Pavel; /Prague, Inst. Phys.; Lauret, Jerome; /Brookhaven; Hanushevsky, Andrew; /SLAC; Shoshani, Arie; /LBL, Berkeley; Sim, Alex; /LBL, Berkeley; Gu, Junmin; /LBL, Berkeley

2011-11-10

Facing the reality of storage economics, NP experiments such as RHIC/STAR have been engaged in a shift of the analysis model, and now heavily rely on using cheap disks attached to processing nodes, as such a model is extremely beneficial over expensive centralized storage. Additionally, exploiting storage aggregates with enhanced distributed computing capabilities such as dynamic space allocation (lifetime of spaces), file management on shared storages (lifetime of files, pinning file), storage policies or a uniform access to heterogeneous storage solutions is not an easy task. The Xrootd/Scalla system allows for storage aggregation. We will present an overview of the largest deployment of Scalla (Structured Cluster Architecture for Low Latency Access) in the world spanning over 1000 CPUs co-sharing the 350 TB Storage Elements and the experience on how to make such a model work in the RHIC/STAR standard analysis framework. We will explain the key features and approach on how to make access to mass storage (HPSS) possible in such a large deployment context. Furthermore, we will give an overview of a fully 'gridified' solution using the plug-and-play features of Scalla architecture, replacing standard storage access with grid middleware SRM (Storage Resource Manager) components designed for space management and will compare the solution with the standard Scalla approach in use in STAR for the past 2 years. Integration details, future plans and status of development will be explained in the area of best transfer strategy between multiple-choice data pools and best placement with respect of load balancing and interoperability with other SRM aware tools or implementations.

Esterification Reaction Utilizing Sense of Smell and Eyesight for Conversion and Catalyst Recovery Monitoring

Science.gov (United States)

Janssens, Nikki; Wee, Lik H.; Martens, Johan A.

2014-01-01

The esterification reaction of salicylic acid with ethanol is performed in presence of dissolved 12-tungstophosphoric Brønsted-Lowry acid catalyst, a Keggin-type polyoxometalate (POM). The monitoring of the reaction with smell and the recovery of the catalyst with sight is presented. Formation of the sweet-scented ester is apparent from the smell.…

Development of inspection techniques for quantitatively measuring surface contamination on SRM hardware

Science.gov (United States)

Law, R. D.

1989-01-01

A contaminant is any material or substance which is potentially undesirable or which may adversely affect any part, component, or assembly. Contamination control of SRM hardware surfaces is a serious concern, for both Thiokol and NASA, with particular concern for contaminants which may adversely affect bonding surfaces. The purpose of this study is to develop laboratory analytical techniques which will make it possible to certify the cleanliness of any designated surface, with special focus on particulates (dust, dirt, lint, etc.), oils (hydrocarbons, silicones, plasticizers, etc.), and greases (HD-2, fluorocarbon grease, etc.). The hardware surfaces of concern will include D6AC steel, aluminum alloys, anodized aluminum alloys, glass/phenolic, carbon/phenolic, NBR/asbestos-silica, and EPDM rubber.

Simulation of Snowmelt Runoff Using SRM Model and Comparison With Neural Networks ANN and ANFIS (Case Study: Kardeh dam basin

Directory of Open Access Journals (Sweden)

morteza akbari

2017-03-01

Full Text Available Introduction: Snowmelt runoff plays an important role in providing water and agricultural resources, especially in mountainous areas. There are different methods to simulate the process of snowmelt. Inter alia, degree-day model, based on temperature-index is more cited. Snowmelt Runoff Model is a conceptual hydrological model to simulate and predict the daily flow of rivers in the mountainous basins on the basis of comparing the accuracy of AVHRR and TM satellite images to determine snow cover in Karun Basin. Additionally, overestimation of snow-covered area decreased with increasing spatial resolution of satellite data.Studies conducted in the Zayandehrood watershed dam, showed that in the calculation of the snow map cover, changes from MODIS satellite imagery, at the time that the image does not exist, using the digital elevation model and regression analysis can provide to estimate the appropriate data from satellites. In the study of snow cover in eastern Turkey, in the mountainous regions of the Euphrates River, data from five meteorological stations and MODIS images were used with a resolution of 500 m. The results showed that satellite images have a good accuracy in estimating snow cover. In a Watershed in northern Pakistan in the period from 2000 to 2006, SRM model was used to estimate the snow cover using MODIS images. The purpose of this study was to evaluate the snowmelt runoff using remote sensing data and SRM model for flow simulation, based on statistical parameters in the Kardeh dam basin. Materials and Methods: Kardeh dam basin has an area of about 560 square kilometers and is located in the north of Mashhad. This area is in the East of Hezarmasjed – kopehdagh zone that is one of the main basins of Kashafrood. This basin is a mountainous area. About 261 km of the basin is located at above 2000 m. The lowest point of the basin is at the watershed outlet with1300 meters and the highest point in the basin, in the North West part

Use of INAA, PGAA, and RNAA to determine 30 elements for certification of an SRM; Tomato leaves, 1573a

Energy Technology Data Exchange (ETDEWEB)

Anderson, D L [Food and Drug Administration, Washington, DC (United States). Div. of Contaminants Chemistry; Becker, D A; Lindstrom, R M; Greenberg, R R; Garrity, K M; Mackey, E A [National Inst. of Standards and Technology, Gaithersburg, MD (United States)

1994-03-01

Analyses for certification have been made for the determination of 30 elements in the National Institute of Standards and Technology (NIST) Tomato Leaves renewal reference material, SRM 1573a. Three of the analytical techniques used were instrumental neutron activation analysis (INAA), radiochemical neutron activation analysis (RNAA), and prompt gamma activation analysis (PGAA). These techniques provided data on 19 elements by INAA, 10 elements by PGAA, and 7 elements by RNAA, with some overlap between techniques. For example, INAA was able to obtain overall analytical uncertainties (at the 95 % confidence level) averaging [+-] 2.2 % for major and minor constituents (Ca, Mg, K), [+-] 3.3 % for constituents from 1 to 1000 [mu]g/g (Na, Fe, Al, Mn, Ba, Zn, Rb, La, Cr), and [+-] 6.4 % for elements between 10 and 1000 ng/g (Co, V, Se, Th, Sc, Sb), using sample dry weights of approximately 150 mg. These analyses represent the most extensive use to date of nuclear analytical techniques in the certification of a trace element SRM at NIST. (author) 6 refs.; 3 tabs.

Perspective: Chemical reactions in ionic liquids monitored through the gas (vacuum)/liquid interface.

Science.gov (United States)

Maier, F; Niedermaier, I; Steinrück, H-P

2017-05-07

This perspective analyzes the potential of X-ray photoelectron spectroscopy under ultrahigh vacuum (UHV) conditions to follow chemical reactions in ionic liquids in situ. Traditionally, only reactions occurring on solid surfaces were investigated by X-ray photoelectron spectroscopy (XPS) in situ. This was due to the high vapor pressures of common liquids or solvents, which are not compatible with the required UHV conditions. It was only recently realized that the situation is very different when studying reactions in Ionic Liquids (ILs), which have an inherently low vapor pressure, and first studies have been performed within the last years. Compared to classical spectroscopy techniques used to monitor chemical reactions, the advantage of XPS is that through the analysis of their core levels all relevant elements can be quantified and their chemical state can be analyzed under well-defined (ultraclean) conditions. In this perspective, we cover six very different reactions which occur in the IL, with the IL, or at an IL/support interface, demonstrating the outstanding potential of in situ XPS to gain insights into liquid phase reactions in the near-surface region.

A multimodal optical and electrochemical device for monitoring surface reactions: redox active surfaces in porous silicon Rugate filters.

Science.gov (United States)

Ciampi, Simone; Guan, Bin; Darwish, Nadim A; Zhu, Ying; Reece, Peter J; Gooding, J Justin

2012-12-21

Herein, mesoporous silicon (PSi) is configured as a single sensing device that has dual readouts; as a photonic crystal sensor in a Rugate filter configuration, and as a high surface area porous electrode. The as-prepared PSi is chemically modified to provide it with stability in aqueous media and to allow for the subsequent coupling of chemical species, such as via Cu(I)-catalyzed cycloaddition reactions between 1-alkynes and azides ("click" reactions). The utility of the bimodal capabilities of the PSi sensor for monitoring surface coupling procedures is demonstrated by the covalent coupling of a ferrocene derivative, as well as by demonstrating ligand-exchange reactions (LER) at the PSi surface. Both types of reactions were monitored through optical reflectivity measurements, as well as electrochemically via the oxidation/reduction of the surface tethered redox species.

The Assessment of Selectivity in Different Quadrupole-Orbitrap Mass Spectrometry Acquisition Modes

Science.gov (United States)

Berendsen, Bjorn J. A.; Wegh, Robin S.; Meijer, Thijs; Nielen, Michel W. F.

2015-02-01

Selectivity of the confirmation of identity in liquid chromatography (tandem) mass spectrometry using Q-Orbitrap instrumentation was assessed using different acquisition modes based on a representative experimental data set constructed from 108 samples, including six different matrix extracts and containing over 100 analytes each. Single stage full scan, all ion fragmentation, and product ion scanning were applied. By generating reconstructed ion chromatograms using unit mass window in targeted MS2, selected reaction monitoring (SRM), regularly applied using triple-quadrupole instruments, was mimicked. This facilitated the comparison of single stage full scan, all ion fragmentation, (mimicked) SRM, and product ion scanning applying a mass window down to 1 ppm. Single factor Analysis of Variance was carried out on the variance (s2) of the mass error to determine which factors and interactions are significant parameters with respect to selectivity. We conclude that selectivity is related to the target compound (mainly the mass defect), the matrix, sample clean-up, concentration, and mass resolution. Selectivity of the different instrumental configurations was quantified by counting the number of interfering peaks observed in the chromatograms. We conclude that precursor ion selection significantly contributes to selectivity: monitoring of a single product ion at high mass accuracy with a 1 Da precursor ion window proved to be equally selective or better to monitoring two transition products in mimicked SRM. In contrast, monitoring a single fragment in all ion fragmentation mode results in significantly lower selectivity versus mimicked SRM. After a thorough inter-laboratory evaluation study, the results of this study can be used for a critical reassessment of the current identification points system and contribute to the next generation of evidence-based and robust performance criteria in residue analysis and sports doping.

Determination of cross sections of nuclear reactions to use Al as monitoring foil in heavy ion irradiation with 20Ne projectile

International Nuclear Information System (INIS)

Chowdhury, D.P.; Datta, J.; Guin, R.; Verma, R.

2009-01-01

The beam current is generally accurately measured using monitoring foils during the irradiation of thick samples by high energy ion beams. The cross sections of many nuclear reactions induced by light particles are available in literature for use as monitoring foil. However, such cross sections of heavy ion induced reactions are not reported much for their use in applied works. We have determined cross sections of two nuclear reactions, 27 Al ( 20 Ne,2p2n) 43 Sc and 27 Al ( 20 Ne, 2pn) 44m Sc, to use Al as monitoring foil for the irradiation with 20 Ne heavy ion beam. (author)

A selected reaction monitoring-based analysis of acute phase proteins in interstitial fluids from experimental equine wounds healing by secondary intention

DEFF Research Database (Denmark)

Bundgaard, Louise; Bendixen, Emøke; Sørensen, Mette Aa

2016-01-01

, ceruloplasmin, prothrombin, and α-1-antitrypsin in dialysate from limb wounds were significantly higher than in dialysate from body wounds. This is the first report of simultaneous analysis of a panel of APPs using the QconCAT-SRM technology. The microdialysis technique in combination with the Qcon...

Comparison of Gas Chromatography-Mass Spectrometry and Gas Chromatography-Tandem Mass Spectrometry with Electron Ionization and Negative-Ion Chemical Ionization for Analyses of Pesticides at Trace Levels in Atmospheric Samples

Directory of Open Access Journals (Sweden)

Renata Raina

2008-01-01

Full Text Available A comparison of detection limits of gas chromatography-mass spectrometry (GC-MS in selected ion monitoring (SIM with gas chromatography-tandem mass spectrometry (GC-MS/MS in selected reaction monitoring (SRM mode with both electron ionization (EI and negative-ion chemical ionization (NCI are presented for over 50 pesticides ranging from organochlorines (OCs, organophosphorus pesticides (OPs and pre-emergent herbicides used in the Canadian prairies (triallate, trifluralin, ethalfluralin. The developed GC-EI/SIM, GC-NCI/SIM, and GC-NCI/SRM are suitable for the determination of pesticides in air sample extracts at concentrations <100 pg µL -1 (< 100 pg m -3 in air. No one method could be used to analyze the range of pre-emergent herbicides, OPs, and OCs investigated. In general GC-NCI/SIM provided the lowest method detection limits (MDLs commonly 2.5-10 pg µL -1 along with best confirmation (<25% RSD of ion ratio, while GC-NCI/SRM is recommended for use where added selectivity or confirmation is required (such as parathion-ethyl, tokuthion, carbofenothion. GC-EI/SRM at concentration < 100 pg µL -1 was not suitable for most pesticides. GC-EI/SIM was more prone to interference issues than NCI methods, but gave good sensitivity (MDLs 1-10 pg µL -1 for pesticides with poor NCI response (OPs: sulfotep, phorate, aspon, ethion, and OCs: alachlor, aldrin, perthane, and DDE, DDD, DDT.

[Enlightenment of adverse reaction monitoring on safety evaluation of traditional Chinese medicines].

Science.gov (United States)

Song, Hai-bo; Du, Xiao-xi; Ren, Jing-tian; Yang, Le; Guo, Xiao-xin; Pang, Yu

2015-04-01

The adverse reaction monitoring is important in warning the risks of traditional Chinese medicines at an early stage, finding potential quality problems and ensuring the safe clinical medication. In the study, efforts were made to investigate the risk signal mining techniques in line with the characteristics of traditional Chinese medicines, particularly the complexity in component, processing, compatibility, preparation and clinical medication, find early risk signals of traditional Chinese medicines and establish a traditional Chinese medicine safety evaluation system based on adverse reaction risk signals, in order to improve the target studies on traditional Chinese medicine safety, effective and timely control risks and solve the existing frequent safety issue in traditional Chinese medicines.

A High Torque Density Axial Flux SRM with Modular Stator

Directory of Open Access Journals (Sweden)

Y Ebrahimi

2015-12-01

Full Text Available A novel structure of switched reluctance motors (SRMs is proposed. The proposed structure uses the benefits of the axial flux path, short flux path, segmental rotor, and flux reversal free stator motors all together to improve the torque density of the SRMs. The main geometrical, electrical and physical specifications are presented. In addition, some features of the proposed structure are compared with those of a state-of-the-art radial flux SRM, considered as a reference motor. Then, the proposed structure is modified by employing a higher number of rotor segments than the stator modules and at the same time, reshaped stator modules tips. Achieved results reveal that, compared with the reference motor, the proposed and the modified proposed motors deliver about the same torque with 36.5% and 46.7% lower active material mass, respectively. The efficiency and torque production capability for the extended current densities are also retained. These make the proposed structures a potentially proper candidate for the electric vehicles (EVs and hybrid electric vehicles (HEVs as an in-wheel motor.

Milk and serum standard reference materials for monitoring organic contaminants in human samples.

Science.gov (United States)

Schantz, Michele M; Eppe, Gauthier; Focant, Jean-François; Hamilton, Coreen; Heckert, N Alan; Heltsley, Rebecca M; Hoover, Dale; Keller, Jennifer M; Leigh, Stefan D; Patterson, Donald G; Pintar, Adam L; Sharpless, Katherine E; Sjödin, Andreas; Turner, Wayman E; Vander Pol, Stacy S; Wise, Stephen A

2013-02-01

Four new Standard Reference Materials (SRMs) have been developed to assist in the quality assurance of chemical contaminant measurements required for human biomonitoring studies, SRM 1953 Organic Contaminants in Non-Fortified Human Milk, SRM 1954 Organic Contaminants in Fortified Human Milk, SRM 1957 Organic Contaminants in Non-Fortified Human Serum, and SRM 1958 Organic Contaminants in Fortified Human Serum. These materials were developed as part of a collaboration between the National Institute of Standards and Technology (NIST) and the Centers for Disease Control and Prevention (CDC) with both agencies contributing data used in the certification of mass fraction values for a wide range of organic contaminants including polychlorinated biphenyl (PCB) congeners, chlorinated pesticides, polybrominated diphenyl ether (PBDE) congeners, and polychlorinated dibenzo-p-dioxin (PCDD) and dibenzofuran (PCDF) congeners. The certified mass fractions of the organic contaminants in unfortified samples, SRM 1953 and SRM 1957, ranged from 12 ng/kg to 2200 ng/kg with the exception of 4,4'-DDE in SRM 1953 at 7400 ng/kg with expanded uncertainties generally <14 %. This agreement suggests that there were no significant biases existing among the multiple methods used for analysis.

Performance monitoring and response conflict resolution associated with choice stepping reaction tasks.

Science.gov (United States)

Watanabe, Tatsunori; Tsutou, Kotaro; Saito, Kotaro; Ishida, Kazuto; Tanabe, Shigeo; Nojima, Ippei

2016-11-01

Choice reaction requires response conflict resolution, and the resolution processes that occur during a choice stepping reaction task undertaken in a standing position, which requires maintenance of balance, may be different to those processes occurring during a choice reaction task performed in a seated position. The study purpose was to investigate the resolution processes during a choice stepping reaction task at the cortical level using electroencephalography and compare the results with a control task involving ankle dorsiflexion responses. Twelve young adults either stepped forward or dorsiflexed the ankle in response to a visual imperative stimulus presented on a computer screen. We used the Simon task and examined the error-related negativity (ERN) that follows an incorrect response and the correct-response negativity (CRN) that follows a correct response. Error was defined as an incorrect initial weight transfer for the stepping task and as an incorrect initial tibialis anterior activation for the control task. Results revealed that ERN and CRN amplitudes were similar in size for the stepping task, whereas the amplitude of ERN was larger than that of CRN for the control task. The ERN amplitude was also larger in the stepping task than the control task. These observations suggest that a choice stepping reaction task involves a strategy emphasizing post-response conflict and general performance monitoring of actual and required responses and also requires greater cognitive load than a choice dorsiflexion reaction. The response conflict resolution processes appear to be different for stepping tasks and reaction tasks performed in a seated position.

Chemical methods and techniques to monitor early Maillard reaction in milk products; A review.

Science.gov (United States)

Aalaei, Kataneh; Rayner, Marilyn; Sjöholm, Ingegerd

2018-01-23

Maillard reaction is an extensively studied, yet unresolved chemical reaction that occurs as a result of application of the heat and during the storage of foods. The formation of advanced glycation end products (AGEs) has been the focus of several investigations recently. These molecules which are formed at the advanced stage of the Maillard reaction, are suspected to be involved in autoimmune diseases in humans. Therefore, understanding to which extent this reaction occurs in foods, is of vital significance. Because of their composition, milk products are ideal media for this reaction, especially when application of heat and prolonged storage are considered. Thus, in this work several chemical approaches to monitor this reaction in an early stage are reviewed. This is mostly done regarding available lysine blockage which takes place in the very beginning of the reaction. The most popular methods and their applications to various products are reviewed. The methods including their modifications are described in detail and their findings are discussed. The present paper provides an insight into the history of the most frequently-used methods and provides an overview on the indicators of the Maillard reaction in the early stage with its focus on milk products and especially milk powders.

Mechanical properties, microstructure and magnetic properties of composite magnet base on SrO.6Fe_2O_3 (SRM)-thermoplastic and thermoset polymer

International Nuclear Information System (INIS)

Grace Tj Sulungbudi; Aloma Karo Karo; Mujamilah; Sudirman

2010-01-01

The use of magnets in industrial applications do not always require high magnetic properties. Therefore, the use of polymer as a matrix that serves as a binder can be applied to obtain lightweight, flexible and cheap composite magnet. This report discuss composite magnet base on SrO.6Fe_2O_3(SRM)-thermoplastic and thermoset polymer. Thermoplastic polymer consist of polypropylene (PP) type of PP2 and PP10 and polyethylene (PE) type of LDPE were used. For thermoset polymer, epoxy and polyester were used. Synthesis of composite magnet based on thermoplastic polymer (PP2, PP10, LDPE) were carried using the blending method, while the thermoset composites magnet using casting method. Thermoplastic composite magnets were prepared with compositions of 50, 41, 38, 33 and 29 % weight of SRM with the blending temperature of 160 °C for LDPE and 180 °C for PP2 and PP10. For thermoset composite magnets, the compositions were 30, 40, 50 and 60 % by weight of SRM. The mechanical test conducted include tensile strength and elongation at break. Microstructure on the surface of the composite materials were observed using SEM (Scanning Electron Microscope) and the magnetic properties were measured using VSM (Vibrating Sample Magnetometer). The SEM results showed the formation of flat shape powder particle with size of 1.6 µm. In general, the mechanical properties of polypropylene polymer composite magnet are better than that using polyethylene (LDPE) binder. For polypropylene binder PP10 is better than PP2. Magnetic properties are not significantly affected by the change of polymer or binder types. (author)

Monitoring coping style moderates emotional reactions to genetic testing for hereditary nonpolyposis colorectal cancer: a longitudinal study.

Science.gov (United States)

Shiloh, S; Koehly, L; Jenkins, J; Martin, J; Hadley, D

2008-08-01

The emotional effects of genetic testing for hereditary nonpolyposis colorectal cancer (HNPCC) provided within a counseling program were assessed among 253 individuals. Assessments were scheduled at baseline before testing, and again after 6 and 12 months post-test. Negative emotional reactions were evaluated using the Revised Impact of Event Scale and the Center for Epidemiological Studies-Depression Scale. Monitoring coping style was assessed at baseline using the Miller Behavioral Style Scale. Mean reductions were indicated in distress and depression levels within the first 6 months after counseling and testing. High monitors were generally more distressed than low monitors, specifically if they had indeterminate or positive results. Genetic counseling and testing for HNPCC do not result in long-term distress for most people. Of the variables investigated, only time and coping style have main effects on emotional reactions, and the impacts of mutation status are moderated by coping style. Psychological interventions, aimed to alleviate adverse emotional effects, were suggested for certain participants, i.e. recipients of positive or indeterminate results who are high monitors.

Measurement of the fluorine content of three NBS standard reference materials by use of the /sup 19/F(p, p'. gamma. )/sup 19/F reaction

Energy Technology Data Exchange (ETDEWEB)

Hanson, A L; Kraner, H W; Shroy, R E; Jones, K W [Brookhaven National Lab., Upton, NY (USA)

1984-08-01

The fluorine contents of National Bureau of Standards (NBS) Standard Reference Materials (SRM) 91, opal glass; 120b, phosphate rock; and 2671a, freeze-dried urine; have been measured using the /sup 19/F(p,p'..gamma..)/sup 19/F reaction at a proton energy of 3.1 MeV. The results are in good agreement with the values certified by the NBS.

Monitoring of Adverse Drug Reactions Associated with Antihypertensive Medicines at a University Teaching Hospital in New Delhi

Directory of Open Access Journals (Sweden)

Fowad Khurshid

2012-09-01

Full Text Available Aim To monitor the adverse drug reactions (ADRs caused by antihypertensive medicines prescribed in a university teaching hospital.Methods:he present work was an open, non-comparative, observational study conducted on hypertensive patients attending the Medicine OPD of Majeedia Hospital, Jamia Hamdard, New Delhi, India by conducting patient interviews and recording the data on ADR monitoring form as recommended by Central Drugs Standard Control Organization (CDSCO, Government of India.Results:A total of 21 adverse drug reactions were observed in 192 hypertensive patients. Incidence of adverse drug reactions was found to be higher in patients more than 40 years in age, and females experienced more ADRs (n = 14, 7.29 % than males, 7 (3.64 %. Combination therapy was associated with more number of adverse drug reactions (66.7 % as against monotherapy (33.3 %. Calcium channel blockers were found to be the most frequently associated drugs with adverse drug reactions (n = 7, followed by diuretics (n = 5, and beta- blockers (n = 4. Among individual drugs, amlodipine was found to be the commonest drug associated with adverse drug reactions (n = 7, followed by torasemide (n = 3. Adverse drug reactions associated with central nervous system were found to be the most frequent (42.8 % followed by musculo-skeletal complaints (23.8 % and gastro-intestinal disorders (14.3 %. Conclusions:The present pharmacovigilance study represents the adverse drug reaction profile of the antihypertensive medicines prescribed in our university teaching hospital. The above findings would be useful for physicians in rational prescribing. Calcium channel blockers were found to be the most frequently associated drugs with adverse drug reactions.

A Parallel Reaction Monitoring Mass Spectrometric Method for Analysis of Potential CSF Biomarkers for Alzheimer's Disease

DEFF Research Database (Denmark)

Brinkmalm, Gunnar; Sjödin, Simon; Simonsen, Anja Hviid

2018-01-01

SCOPE: The aim of this study was to develop and evaluate a parallel reaction monitoring mass spectrometry (PRM-MS) assay consisting of a panel of potential protein biomarkers in cerebrospinal fluid (CSF). EXPERIMENTAL DESIGN: Thirteen proteins were selected based on their association with neurode......SCOPE: The aim of this study was to develop and evaluate a parallel reaction monitoring mass spectrometry (PRM-MS) assay consisting of a panel of potential protein biomarkers in cerebrospinal fluid (CSF). EXPERIMENTAL DESIGN: Thirteen proteins were selected based on their association...... with neurodegenerative diseases and involvement in synaptic function, secretory vesicle function, or innate immune system. CSF samples were digested and two to three peptides per protein were quantified using stable isotope-labeled peptide standards. RESULTS: Coefficients of variation were generally below 15%. Clinical...

Effect of microwave double absorption on hydrogen generation from methanol steam reforming

Energy Technology Data Exchange (ETDEWEB)

Chen, Wei-Hsin; Lin, Bo-Jhih [Department of Greenergy, National University of Tainan, Tainan 700 (China)

2010-03-15

Hydrogen generation from steam reforming of methanol (SRM) with a CuO/ZnO/Al{sub 2}O{sub 3} catalyst was investigated in the study; particular emphasis was placed on the reactions of SRM exposed to an environment with microwave irradiation. By virtue of the double absorption of microwaves by both the reagents and the catalyst, the experiments suggested that the SRM could be heated and triggered rapidly within a short time, and the methanol conversion from SRM with microwave heating was high compared to that with conventional heating. The obtained results also indicated that, when the reaction temperature was as high as 250 C, thermodynamic equilibrium governed the SRM, whereas the reaction was kinetically controlled for the temperature lower than 250 C. Contrary to Le Chatelier's principle, it was noted that an increase in S/C ratio decreased methanol conversion. This can be explained by the fact that water absorbs microwave irradiation stronger than methanol. The performance of the SRM was evaluated based on the carbon conservation method and the nitrogen tracer method. It was found that the latter was also capable of providing an accurate prediction on methanol conversion, even though the flow rate of the product gas was not measured. (author)

Manipulating and Monitoring On-Surface Biological Reactions by Light-Triggered Local pH Alterations.

Science.gov (United States)

Peretz-Soroka, Hagit; Pevzner, Alexander; Davidi, Guy; Naddaka, Vladimir; Kwiat, Moria; Huppert, Dan; Patolsky, Fernando

2015-07-08

Significant research efforts have been dedicated to the integration of biological species with electronic elements to yield smart bioelectronic devices. The integration of DNA, proteins, and whole living cells and tissues with electronic devices has been developed into numerous intriguing applications. In particular, the quantitative detection of biological species and monitoring of biological processes are both critical to numerous areas of medical and life sciences. Nevertheless, most current approaches merely focus on the "monitoring" of chemical processes taking place on the sensing surfaces, and little efforts have been invested in the conception of sensitive devices that can simultaneously "control" and "monitor" chemical and biological reactions by the application of on-surface reversible stimuli. Here, we demonstrate the light-controlled fine modulation of surface pH by the use of photoactive molecularly modified nanomaterials. Through the use of nanowire-based FET devices, we showed the capability of modulating the on-surface pH, by intensity-controlled light stimulus. This allowed us simultaneously and locally to control and monitor pH-sensitive biological reactions on the nanodevices surfaces, such as the local activation and inhibition of proteolytic enzymatic processes, as well as dissociation of antigen-antibody binding interactions. The demonstrated capability of locally modulating the on-surface effective pH, by a light stimuli, may be further applied in the local control of on-surface DNA hybridization/dehybridization processes, activation or inhibition of living cells processes, local switching of cellular function, local photoactivation of neuronal networks with single cell resolution and so forth.

Neutron activation analysis with pre- and post-irradiation chemical separation for the value assignments of Al, V, and Ni in the new bovine liver SRM 1577C

International Nuclear Information System (INIS)

Zeisler, R.; Tomlin, B.E.; Murphy, K.E.

2009-01-01

Instrumental neutron activation analysis as carried out at the National Institute of Standards and Technology (NIST) is inadequate for determining Al, Ni, and V at the levels found in the newly prepared Standard Reference Material R (SRM) 1577c Bovine Liver. To overcome shortcomings in the value assignment, the authors initiated a cooperative approach using NAA with previously established chemical separation procedures and with significantly different neutron energy spectra to determine Al and V with pre-irradiation separation of the elements at NIST, and V and Ni with post-irradiation separation at the Nuclear Physics Institute Rez. The determinations were confirmed with the analyses of several SRMs. The work supported the certification of mass fraction values for V and Ni in SRM 1577c. (author)

Monte Carlo Uncertainty Quantification Using Quasi-1D SRM Ballistic Model

Directory of Open Access Journals (Sweden)

Davide Viganò

2016-01-01

Full Text Available Compactness, reliability, readiness, and construction simplicity of solid rocket motors make them very appealing for commercial launcher missions and embarked systems. Solid propulsion grants high thrust-to-weight ratio, high volumetric specific impulse, and a Technology Readiness Level of 9. However, solid rocket systems are missing any throttling capability at run-time, since pressure-time evolution is defined at the design phase. This lack of mission flexibility makes their missions sensitive to deviations of performance from nominal behavior. For this reason, the reliability of predictions and reproducibility of performances represent a primary goal in this field. This paper presents an analysis of SRM performance uncertainties throughout the implementation of a quasi-1D numerical model of motor internal ballistics based on Shapiro’s equations. The code is coupled with a Monte Carlo algorithm to evaluate statistics and propagation of some peculiar uncertainties from design data to rocker performance parameters. The model has been set for the reproduction of a small-scale rocket motor, discussing a set of parametric investigations on uncertainty propagation across the ballistic model.

Toward a high-throughput method for determining vicine and convicine levels in faba bean seeds using flow injection analysis combined with tandem mass spectrometry.

Science.gov (United States)

Purves, Randy W; Khazaei, Hamid; Vandenberg, Albert

2018-08-01

Although faba bean provides environmental and health benefits, vicine and convicine (v-c) limit its use as a source of vegetable protein. Crop improvement efforts to minimize v-c concentration require low-cost, rapid screening methods to distinguish between high and low v-c genotypes to accelerate development of new cultivars and to detect out-crossing events. To assist crop breeders, we developed a unique and rapid screening method that uses a 60 s instrumental analysis step to accurately distinguish between high and low v-c genotypes. The method involves flow injection analysis (FIA) coupled with tandem mass spectrometry (i.e., selective reaction monitoring, SRM). Using seeds with known v-c levels as calibrants, measured v-c levels were comparable with liquid chromatography (LC)-SRM results and the method was used to screen 370 faba bean genotypes. Widespread use of FIA-SRM will accelerate breeding of low v-c faba bean, thereby alleviating concerns about anti-nutritional effects of v-c in this crop. Copyright © 2018 Elsevier Ltd. All rights reserved.

Unattended reaction monitoring using an automated microfluidic sampler and on-line liquid chromatography.

Science.gov (United States)

Patel, Darshan C; Lyu, Yaqi Fara; Gandarilla, Jorge; Doherty, Steve

2018-04-03

In-process sampling and analysis is an important aspect of monitoring kinetic profiles and impurity formation or rejection, both in development and during commercial manufacturing. In pharmaceutical process development, the technology of choice for a substantial portion of this analysis is high-performance liquid chromatography (HPLC). Traditionally, the sample extraction and preparation for reaction characterization have been performed manually. This can be time consuming, laborious, and impractical for long processes. Depending on the complexity of the sample preparation, there can be variability introduced by different analysts, and in some cases, the integrity of the sample can be compromised during handling. While there are commercial instruments available for on-line monitoring with HPLC, they lack capabilities in many key areas. Some do not provide integration of the sampling and analysis, while others afford limited flexibility in sample preparation. The current offerings provide a limited number of unit operations available for sample processing and no option for workflow customizability. This work describes development of a microfluidic automated program (MAP) which fully automates the sample extraction, manipulation, and on-line LC analysis. The flexible system is controlled using an intuitive Microsoft Excel based user interface. The autonomous system is capable of unattended reaction monitoring that allows flexible unit operations and workflow customization to enable complex operations and on-line sample preparation. The automated system is shown to offer advantages over manual approaches in key areas while providing consistent and reproducible in-process data. Copyright © 2017 Elsevier B.V. All rights reserved.

Liquid Chromatography with Post-Column Reagent Addition of Ammonia in Methanol Coupled to Negative Ion Electrospray Ionization Tandem Mass Spectrometry for Determination of Phenoxyacid Herbicides and their Degradation Products in Surface Water

Directory of Open Access Journals (Sweden)

Michele L. Etter

2010-02-01

Full Text Available A new liquid chromatography (LC-negative ion electrospray ionization (ESI–tandem mass spectrometry (MS/MS method with post-column addition of ammonia in methanol has been developed for the analysis of acid herbicides: 2,4-dichlorophenoxy ace- tic acid, 4-chloro-o-tolyloxyacetic acid, 2-(2-methyl-4-chlorophenoxybutyric acid, mecoprop, dichlorprop, 4-(2,4-dichlorophenoxy butyric acid, 2,4,5-trichlorophenoxy propionic acid, dicamba and bromoxynil, along with their degradation products: 4-chloro-2- methylphenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and 3,5-dibromo-4-hydroxybenzoic acid. The samples were extracted from the surface water matrix using solid-phase extraction (SPE with a polymeric sorbent and analyzed with LC ESI- with selected reaction monitoring (SRM using a three-point confirmation approach. Chromatography was performed on a Zorbax Eclipse XDB-C18 (50 × 4.6 mm i.d., 1.8 µm with a gradient elution using water-methanol with 2 mM ammonium acetate mobile phase at a flow rate of 0.15 mL/min. Ammonia in methanol (0.8 M was added post-column at a flow rate of 0.05 mL/min to enhance ionization of the deg- radation products in the MS source. One SRM transition was used for quantitative analysis while the second SRM along with the ratio of SRM1/SRM2 within the relative standard deviation determined by standards for each individual pesticide and retention time match were used for confirmation. The standard deviation of ratio of SRM1/SRM2 obtained from standards run on the day of analysis for different phenoxyacid herbicides ranged from 3.9 to 18.5%. Limits of detection (LOD were between 1 and 15 ng L-1 and method detection limits (MDL with strict criteria requiring

Corrosion potential detection method, potential characteristic simulation method for reaction rate and plant monitoring system using the same

International Nuclear Information System (INIS)

Sakai, Masanori; Onaka, Noriyuki; Takahashi, Tatsuya; Yamanaka, Hiroshi.

1995-01-01

In a calculation controlling device for a plant monitoring system, concentrations of materials concerning reaction materials in a certain state of a reaction process, and an actually measured value for the potential of a material in this state are substituted into a reaction rate equation obtained in accordance with a reaction process model. With such procedures, a relation between the reaction rate (current value) and the potential of the material can be obtained. A potential at which the reaction rates of an anode reaction and a cathode reaction contained in a corrosion reaction are made equal is determined by a numerical value calculation, based on an electrochemical hybrid potential logic by using the reaction rate equation, the reaction rate information relative to the corrosion reaction of the material and the concentration of the material concerning the corrosion reaction is obtained by a numerical value calculation. Then, simulation for the corrosion potential is enabled based on the handling corresponding to the actual reaction. Further, even for a portion which can not be measured actually, the corrosion potential can be recognized by simulation. (N.H.)

When big brother is watching: goal orientation shapes reactions to electronic monitoring during online training.

Science.gov (United States)

Watson, Aaron M; Foster Thompson, Lori; Rudolph, Jane V; Whelan, Thomas J; Behrend, Tara S; Gissel, Amanda L

2013-07-01

Web-based training is frequently used by organizations as a convenient and low-cost way to teach employees new knowledge and skills. As web-based training is typically unproctored, employees may be held accountable to the organization by computer software that monitors their behaviors. The current study examines how the introduction of electronic performance monitoring may provoke negative emotional reactions and decrease learning among certain types of e-learners. Through motivated action theory and trait activation theory, we examine the role of performance goal orientation when e-learners are exposed to asynchronous and synchronous monitoring. We show that some e-learners are more susceptible than others to evaluation apprehension when they perceive their activities are being monitored electronically. Specifically, e-learners higher in avoid performance goal orientation exhibited increased evaluation apprehension if they believed asynchronous monitoring was present, and they showed decreased skill attainment as a result. E-learners higher on prove performance goal orientation showed greater evaluation apprehension if they believed real-time monitoring was occurring, resulting in decreased skill attainment. PsycINFO Database Record (c) 2013 APA, all rights reserved.

Effects of confinement on rock mass modulus: A synthetic rock mass modelling (SRM study

Directory of Open Access Journals (Sweden)

I. Vazaios

2018-06-01

Full Text Available The main objective of this paper is to examine the influence of the applied confining stress on the rock mass modulus of moderately jointed rocks (well interlocked undisturbed rock mass with blocks formed by three or less intersecting joints. A synthetic rock mass modelling (SRM approach is employed to determine the mechanical properties of the rock mass. In this approach, the intact body of rock is represented by the discrete element method (DEM-Voronoi grains with the ability of simulating the initiation and propagation of microcracks within the intact part of the model. The geometry of the pre-existing joints is generated by employing discrete fracture network (DFN modelling based on field joint data collected from the Brockville Tunnel using LiDAR scanning. The geometrical characteristics of the simulated joints at a representative sample size are first validated against the field data, and then used to measure the rock quality designation (RQD, joint spacing, areal fracture intensity (P21, and block volumes. These geometrical quantities are used to quantitatively determine a representative range of the geological strength index (GSI. The results show that estimating the GSI using the RQD tends to make a closer estimate of the degree of blockiness that leads to GSI values corresponding to those obtained from direct visual observations of the rock mass conditions in the field. The use of joint spacing and block volume in order to quantify the GSI value range for the studied rock mass suggests a lower range compared to that evaluated in situ. Based on numerical modelling results and laboratory data of rock testing reported in the literature, a semi-empirical equation is proposed that relates the rock mass modulus to confinement as a function of the areal fracture intensity and joint stiffness. Keywords: Synthetic rock mass modelling (SRM, Discrete fracture network (DFN, Rock mass modulus, Geological strength index (GSI, Confinement

Summary report of the consultants' meeting on improvements in charged-particle monitor reactions and nuclear data for medical isotope production

International Nuclear Information System (INIS)

Capote Noy, R.; Nortier, F.M.

2011-09-01

A Consultants' Meeting on 'Improvements in Charged-Particle Monitor Reactions and Nuclear Data for Medical Isotope Production' was held at IAEA Headquarters, Vienna, Austria to define the scope, deliverables and appropriate work programme of a possible Coordinated Research Project (CRP) on the subject. The main data areas requiring improvements are monitor reactions for charged-particle beams, production of novel positron emitters, and production of alpha emitters. In all these areas special attention was also given to the need for measurements and re-evaluations of decay data. Detailed deliverables of the planned CRP were proposed. (author)

Improvement of the Torque-Speed Performance and Drive Efficiency in an SRM Using an Optimal Torque Sharing Function

Directory of Open Access Journals (Sweden)

Wei Ye

2018-05-01

Full Text Available In this paper, by evaluating the extreme value of the qth-power current, a torque sharing function (TSF family for reducing the torque ripples in the switched reluctance motor (SRM is proposed. The optimization criteria of the TSF has two secondary objectives, including the maximization of the torque-speed range and the minimization of copper loss. The evaluation indices in terms of the peak phase current, the rms (root mean square phase current, and the torque ripple factor are compared between the proposed TSF family and four conventional TSFs including linear, sinusoidal, exponential, and cubic TSFs. An optimization objective function that combines the maximum absolute value of the rate-of-change of the flux linkage (MAV-RCFL and the qth-power of current is proposed and a weighting factor is used to balance the influence of the two optimization objectives. An optimal TSF can be easily obtained by solving the optimization problem from the TSF family. The proposed TSF is validated by using simulations and experiments with a three-phase 6/4 SRM with 7.5 kW, 3000 rpm, and 270 V DC-link voltage. The dynamic simulation model is implemented in Matlab/Simulink. The results demonstrate the validity and superiority of the proposed control method; the optimal TSF provides better torque-speed performance, and a better reduction in copper loss and torque ripples at high speed, as compared to conventional TSFs.

Sequencing Analysis of Mutant Allele $cdc$28-$srm$ of Protein Kinase CDC28 and Molecular Dynamics Study of Glycine-Rich Loop in Wild-Type and Mutant Allele G16S of CDK2 as Model

CERN Document Server

Koltovaya, N A; Kholmurodov, Kh T; Kretov, D A

2005-01-01

The central role that cyclin-dependent kinases play in the timing of cell division and the high incidence of genetic alteration of CDKs or deregulation of CDK inhibitors in a number of cancers make CDC28 of the yeast \\textit{Saccharomyces cerevisiae }very attractive model for studies of mechanisms of CDK regulation. Earlier it was found that certain gene mutations including \\textit{cdc28-srm} affect cell cycle progression, maintenance of different genetic structures and increase cell sensitivity to ionizing radiation. A~\\textit{cdc28-srm} mutation is not temperature-sensitive mutation and differs from the known \\textit{cdc28-ts }mutations because it has the evident phenotypic manifestations at 30 $^{\\circ}$C. Sequencing analysis of \\textit{cdc28-srm} revealed a single nucleotide substitution G20S. This is a third glycine in a conserved sequence GxGxxG in the G-rich loop positioned opposite the activation T-loop. Despite its demonstrated importance, the role of the G-loop has remained unclear. The crystal stru...

RAPID MONITORING BY QUANTITATIVE POLYMERASE CHAIN REACTION FOR PATHOGENIC ASPERGILLUS DURING CARPET REMOVAL FROM A HOSPITAL

Science.gov (United States)

Monitoring for pathogenic Aspergillus species using a rapid, highly sensitive, quantitative polumerase chain reaction technique during carpet removal in a burn unit provided data which allowed the patients to be safely returned to the re-floored area sooner than if only conventio...

Metal oxide nanoparticle mediated enhanced Raman scattering and its use in direct monitoring of interfacial chemical reactions.

Science.gov (United States)

Li, Li; Hutter, Tanya; Finnemore, Alexander S; Huang, Fu Min; Baumberg, Jeremy J; Elliott, Stephen R; Steiner, Ullrich; Mahajan, Sumeet

2012-08-08

Metal oxide nanoparticles (MONPs) have widespread usage across many disciplines, but monitoring molecular processes at their surfaces in situ has not been possible. Here we demonstrate that MONPs give highly enhanced (×10(4)) Raman scattering signals from molecules at the interface permitting direct monitoring of their reactions, when placed on top of flat metallic surfaces. Experiments with different metal oxide materials and molecules indicate that the enhancement is generic and operates at the single nanoparticle level. Simulations confirm that the amplification is principally electromagnetic and is a result of optical modulation of the underlying plasmonic metallic surface by MONPs, which act as scattering antennae and couple light into the confined region sandwiched by the underlying surface. Because of additional functionalities of metal oxides as magnetic, photoelectrochemical and catalytic materials, enhanced Raman scattering mediated by MONPs opens up significant opportunities in fundamental science, allowing direct tracking and understanding of application-specific transformations at such interfaces. We show a first example by monitoring the MONP-assisted photocatalytic decomposition reaction of an organic dye by individual nanoparticles.

Calculation of neutron monitor reaction cross sections of {sup 90}Zr in energy region up to 100 MeV

Energy Technology Data Exchange (ETDEWEB)

Qingbiao, Shen; Baosheng, Yu; Dunjiu, Cai [Chinese Nuclear Data Center, Beijing, BJ (China)

1996-06-01

Many nuclear data for n + {sup 90}Zr reaction were calculated by using optical model evaporation model and exciton model. The program SPEC, including the first to the sixth particle emission processes, was used in our calculations. The calculated results show that the activation products {sup 89,88}Zr and {sup 88,87}Y are important neutron monitor reaction products for n + {sup 90}Zr reaction in energy range up to 100 MeV. (4 figs.).

Steam reforming and oxidative steam reforming of methanol over CuO-CeO{sub 2} catalysts

Energy Technology Data Exchange (ETDEWEB)

Udani, P.P.C.; Gunawardana, P.V.D.S.; Lee, Hyun Chan; Kim, Dong Hyun [Department of Chemical Engineering, Kyungpook National University, Daegu 702-701 (Korea)

2009-09-15

Steam reforming (SRM) and oxidative steam reforming of methanol (OSRM) were carried out over a series of coprecipitated CuO-CeO{sub 2} catalysts with varying copper content in the range of 30-80 at.% Cu (= 100 x Cu/(Cu + Ce)). The effects of copper content, reaction temperature and O{sub 2} concentration on catalytic activity were investigated. The activity of CuO-CeO{sub 2} catalysts for SRM and OSRM increased with the copper content and 70 at.% CuO-CeO{sub 2} catalyst showed the highest activity in the temperature range of 160-300 C for both SRM and OSRM. After SRM or OSRM, the copper species in the catalysts observed by XRD were mainly metallic copper with small amount of CuO and Cu{sub 2}O, an indication that metallic copper is an active species in the catalysis of both SRM and OSRM. It was observed that the methanol conversion increased considerably with the addition of O{sub 2} into the feed stream, indicating that the partial oxidation of methanol (POM) is much faster than SRM. The optimum 70 at.% CuO-CeO{sub 2} catalyst showed stable activities for both SRM and OSRM reactions at 300 C. (author)

Monitoring, Modeling, and Diagnosis of Alkali-Silica Reaction in Small Concrete Samples

Energy Technology Data Exchange (ETDEWEB)

Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Gribok, Andrei V. [Idaho National Lab. (INL), Idaho Falls, ID (United States); Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2015-09-01

Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. This report describes alkali-silica reaction (ASR) degradation mechanisms and factors influencing the ASR. A fully coupled thermo-hydro-mechanical-chemical model developed by Saouma and Perotti by taking into consideration the effects of stress on the reaction kinetics and anisotropic volumetric expansion is presented in this report. This model is implemented in the GRIZZLY code based on the Multiphysics Object Oriented Simulation Environment. The implemented model in the GRIZZLY code is randomly used to initiate ASR in a 2D and 3D lattice to study the percolation aspects of concrete. The percolation aspects help determine the transport properties of the material and therefore the durability and service life of concrete. This report summarizes the effort to develop small-size concrete samples with embedded glass to mimic ASR. The concrete samples were treated in water and sodium hydroxide solution at elevated temperature to study how ingress of sodium ions and hydroxide ions at elevated temperature impacts concrete samples embedded with glass. Thermal camera was used to monitor the changes in the concrete sample and results are summarized.

Test Capability of Comparative NAA Method in Analysis of Long Lived Element in SRM 1648

International Nuclear Information System (INIS)

Sri-Wardani

2005-01-01

The comparative NAA method had been examine on the analysis of long-lived elements content in air particulate sample of NIST.SRM 1648 for evaluation of a capability of comparative NAA method that used at P2TRR. From the result of analysis it could be determined analysis elements contained in the sample, namely: Sc, Co, Zn, Br, Rb, Sb, Hf and Th with optimum results in bias of 10%. The optimum result of long-lived elements obtained on a good accuracy and precision. From the analysis data obtained showed that the comparative NAA method with Gamma Trac and APTEC software capable to analyze several kinds of elements in environmental samples. Therefore, this method could be implement in biological and healthy samples. (author)

Neutron activation analysis of NBS oyster tissue (SRM 1566) and IAEA animal bone (H-5)

International Nuclear Information System (INIS)

Lepel, E.A.; Laul, J.C.

1983-10-01

Data have been presented for 35 elements determined by INAA for NBS oyster tissue (SRM 1566) and for 38 elements determined by INAA and RNAA for IAEA animal bone (H-5). The experimental data showed excellent agreement with published values wherever the comparison exists. Additional trace-element data in the ppb range have been presented for the elements Sc, Sb, Cs, La, Ce, Nd, Sm, Eu, Tb, Dy, Ho, Yb, Lu, Hf, Ta, W and Th in NBS oyster tissue. Also, additional trace-element data for IAEA animal bone (H-5) in the ppb range for the elements Al, Sc, Co, Rb, Cs, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Tm, Yb, lu, Hf, Ta and Th have been presented

Micro flow reactor chips with integrated luminescent chemosensors for spatially resolved on-line chemical reaction monitoring.

Science.gov (United States)

Gitlin, Leonid; Hoera, Christian; Meier, Robert J; Nagl, Stefan; Belder, Detlev

2013-10-21

Real-time chemical reaction monitoring in microfluidic environments is demonstrated using luminescent chemical sensors integrated in PDMS/glass-based microscale reactors. A fabrication procedure is presented that allows for straightforward integration of thin polymer layers with optical sensing functionality in microchannels of glass-PDMS chips of only 150 μm width and of 10 to 35 μm height. Sensor layers consisting of polystyrene and an oxygen-sensitive platinum porphyrin probe with film thicknesses of about 0.5 to 4 μm were generated by combining spin coating and abrasion techniques. Optimal coating procedures were developed and evaluated. The chip-integrated sensor layers were calibrated and investigated with respect to stability, reproducibility and response times. These microchips allowed observation of dissolved oxygen concentration in the range of 0 to over 40 mg L(-1) with a detection limit of 368 μg L(-1). The sensor layers were then used for observation of a model reaction, the oxidation of sulphite to sulphate in a microfluidic chemical reactor and could observe sulphite concentrations of less than 200 μM. Real-time on-line monitoring of this chemical reaction was realized at a fluorescence microscope setup with 405 nm LED excitation and CCD camera detection.

To track or not to track: user reactions to concepts in longitudinal health monitoring.

Science.gov (United States)

Beaudin, Jennifer S; Intille, Stephen S; Morris, Margaret E

2006-01-01

Advances in ubiquitous computing, smart homes, and sensor technologies enable novel, longitudinal health monitoring applications in the home. Many home monitoring technologies have been proposed to detect health crises, support aging-in-place, and improve medical care. Health professionals and potential end users in the lay public, however, sometimes question whether home health monitoring is justified given the cost and potential invasion of privacy. The aim of the study was to elicit specific feedback from health professionals and laypeople about how they might use longitudinal health monitoring data for proactive health and well-being. Interviews were conducted with 8 health professionals and 26 laypeople. Participants were asked to evaluate mock data visualization displays that could be generated by novel home monitoring systems. The mock displays were used to elicit reactions to longitudinal monitoring in the home setting as well as what behaviors, events, and physiological indicators people were interested in tracking. Based on the qualitative data provided by the interviews, lists of benefits of and concerns about health tracking from the perspectives of the practitioners and laypeople were compiled. Variables of particular interest to the interviewees, as well as their specific ideas for applications of collected data, were documented. Based upon these interviews, we recommend that ubiquitous "monitoring" systems may be more readily adopted if they are developed as tools for personalized, longitudinal self-investigation that help end users learn about the conditions and variables that impact their social, cognitive, and physical health.

A comparative study of 129I content in environmental standard materials IAEA-375, NIST SRM 4354 and NIST SRM 4357 by Thermal Ionization Mass Spectrometry and Accelerator Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Olson, John; Adamic, Mary; Snyder, Darin; Brookhart, Jacob; Hahn, Paula; Watrous, Matthew

2016-11-01

Iodine environmental measurements have consistently been backed up in the literature by standard materials like IAEA-375, Chernobyl Soil. There are not many other sources of a certified reference material for 129I content for mass spectrometry measurements. Some that have been found in the literature include NIST-4354 and NIST-4357. They are still available at the time of this writing. They don’t have certified content or isotopic values. There has been some work in the literature to show that iodine is present, but there hasn’t been enough to establish a consensus value. These materials have been analyzed at INL through two separate mass spectrometry techniques. They involve a combustion method of the starting material in oxygen, followed by TIMS analysis and a leaching preparation analyzed by accelerator mass spectrometry. Combustion/TIMS preparation of NIST SRM-4354 resulted in a 129I/127I ratio of 1.92 x 10-6 which agrees with AMS measurements which measured the 129I/127I ratio to be 1.93 x 10-6.

Liquid Chromatography with Post-Column Reagent Addition of Ammonia in Methanol Coupled to Negative Ion Electrospray Ionization Tandem Mass Spectrometry for Determination of Phenoxyacid Herbicides and their Degradation Products in Surface Water

Directory of Open Access Journals (Sweden)

Renata Raina

2010-01-01

Full Text Available A new liquid chromatography (LC-negative ion electrospray ionization (ESI − –tandem mass spectrometry (MS/MS method with post-column addition of ammonia in methanol has been developed for the analysis of acid herbicides: 2,4-dichlorophenoxy acetic acid, 4-chloro-o-tolyloxyacetic acid, 2-(2-methyl-4-chlorophenoxybutyric acid, mecoprop, dichlorprop, 4-(2,4-dichlorophenoxy butyric acid, 2,4,5-trichlorophenoxy propionic acid, dicamba and bromoxynil, along with their degradation products: 4-chloro-2-methylphenol, 2,4-dichlorophenol, 2,4,5-trichlorophenol and 3,5-dibromo-4-hydroxybenzoic acid. The samples were extracted from the surface water matrix using solid-phase extraction (SPE with a polymeric sorbent and analyzed with LC ESI − with selected reaction monitoring (SRM using a three-point confirmation approach. Chromatography was performed on a Zorbax Eclipse XDB-C18 (50 × 4.6 mm i.d., 1.8 μm with a gradient elution using water-methanol with 2 mM ammonium acetate mobile phase at a flow rate of 0.15 mL/min. Ammonia in methanol (0.8 M was added post-column at a flow rate of 0.05 mL/min to enhance ionization of the degradation products in the MS source. One SRM transition was used for quantitative analysis while the second SRM along with the ratio of SRM1/SRM2 within the relative standard deviation determined by standards for each individual pesticide and retention time match were used for confirmation. The standard deviation of ratio of SRM1/SRM2 obtained from standards run on the day of analysis for different phenoxyacid herbicides ranged from 3.9 to 18.5%. Limits of detection (LOD were between 1 and 15 ng L −1 and method detection limits (MDL with strict criteria requiring <25% deviation of peak area from best-fit line for both SRM1 and SRM2 ranged from 5 to 10 ng L −1 for acid ingredients (except dicamba at 30 ng L −1 and from 2 to 30 ng L −1 for degradation products. The SPE-LC-ESI − MS/MS method permitted low nanogram

Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii

Science.gov (United States)

2013-10-01

Selected reaction monitoring (SRM) studies were performed on a Thermo TSQ Quantum Ultra Triple Stage quadrupole mass spectrometer. The scans of the...well as a PmrC-dependent pEtN addition to the lipid A of E. coli O157:H7 (39). Surprisingly, the canine pathogen Capnocytophaga canimorsus and plant...variety of novel lipid A structures obtained from Francisella tula- rensis live vaccine strain. Innate Immun. 18:268 –278. 44. Balaji V, Jeremiah SS

Branched alkanes from ancient and modern sediments: isomer discrimination by GC/MS with multiple reaction monitoring

Energy Technology Data Exchange (ETDEWEB)

Summons, R.E.

1987-01-01

Linked scanning of a tandem sector mass spectrometer has been used to identify abundant, first field free region (FFR1) unimolecular fragmentations in branched and isoprenoid hydrocarbons. The most intense, structure-specific reactions were selected to establish multiple reaction monitoring (MRM) parameters for GC/MS analysis. This methodology has been used to study the identify of co-eluting and closely eluting hydrocarbon biomarkers from modern and ancient sediments and from extant microorganisms. Some sediments of Cambrian and Proterozoic age have been found to contain suites of monomethylalkanes with all possible isomers present and with little apparent preference for the site of branching.

Real-time monitoring of viscosity changes triggered by chemical reactions using a high-speed imaging method

Directory of Open Access Journals (Sweden)

Wooseok Jung

2015-09-01

Full Text Available We present a method to monitor in real time peptide self-assembly or polymerization events. The temperature controlled modification of a previously reported splash test setup using high speed imaging enables to observe and measure rheological changes in liquid samples and can, in turn, monitor a peptide self-assembly or polymerization reaction accompanied with specific changes in solution viscosity. A series of 2 mm glass beads were dropped into an Fmoc-L3-OMe (methylated Fluorenylmethyloxycarbonyl-trileucine solution mixed with Alcalase 2.4 L (EC 3.4.21.62 or first dipped in Tetramethylethylenediamine (TEMED, a catalyst for acrylamide polymerization, then dropped into acrylamide. The resulting splashes were observed using a high speed camera. The results demonstrate that the viscosity changes of the peptide sample during the peptide self-assembly or acrylamide polymerization affect the specific shape and evolution of the splashing event. Typically, the increase in viscosity while the reaction occurs decreased the size of the splash and the amount of time for the splash to reach maximum extension from the moment for the beads to impact the sample. The ability to observe rheological changes of sample state presents the opportunity to monitor the real time dynamics of peptide self-assembly or cross-polymerization. Keywords: High-speed imaging, Self-assembly, Viscosity sensor

Simultaneous determination of water-soluble vitamins in SRM 1849 Infant/Adult Nutritional Formula powder by liquid chromatography-isotope dilution mass spectrometry.

Science.gov (United States)

Goldschmidt, Robert J; Wolf, Wayne R

2010-05-01

Assessing dietary intake of vitamins from all sources, including foods, dietary supplements, and fortified foods, would be aided considerably by having analytical methodologies that are capable of simultaneous determination of several vitamins. Vitamins naturally present in foods may occur in different chemical forms, with levels ranging over several orders of magnitude. Vitamins in dietary supplements and fortified foods, however, are typically added in a single chemical form, and matrix issues are usually not as complex. These sources should thus be relatively amenable to approaches that aim for simultaneous determination of multiple vitamins. Our recent work has focused on development of liquid chromatography (LC)-UV/fluorescence and LC-tandem mass spectrometry methods for the simultaneous determination of water-soluble vitamins (thiamine, niacin, pyridoxine, pantothenic acid, folic acid, biotin, and riboflavin) in dietary supplement tablets and fortified foods, such as formula powders and breakfast cereals. As part of the validation of our methods and collaboration in characterization of a new NIST SRM 1849 Infant/Adult Nutritional Formula powder, we report data on SRM 1849 using isotope dilution mass spectrometric methods. Use of available NIST Standard Reference Materials(R) as test matrices in our method development and validation gives a benchmark for future application of these methods. We compare three chromatographic approaches and provide data on stability of vitamin standard solutions for LC-based multiple vitamin determinations.

Uranium isotopic composition and uranium concentration in special reference material SRM A (uranium in KCl/LiCl salt matrix)

International Nuclear Information System (INIS)

Graczyk, D.G.; Essling, A.M.; Sabau, C.S.; Smith, F.P.; Bowers, D.L.; Ackerman, J.P.

1997-07-01

To help assure that analysis data of known quality will be produced in support of demonstration programs at the Fuel Conditioning Facility at Argonne National Laboratory-West (Idaho Falls, ID), a special reference material has been prepared and characterized. Designated SRM A, the material consists of individual units of LiCl/KCl eutectic salt containing a nominal concentration of 2.5 wt. % enriched uranium. Analyses were performed at Argonne National Laboratory-East (Argonne, IL) to determine the uniformity of the material and to establish reference values for the uranium concentration and uranium isotopic composition. Ten units from a batch of approximately 190 units were analyzed by the mass spectrometric isotope dilution technique to determine their uranium concentration. These measurements provided a mean value of 2.5058 ± 0.0052 wt. % U, where the uncertainty includes estimated limits to both random and systematic errors that might have affected the measurements. Evidence was found of a small, apparently random, non-uniformity in uranium content of the individual SRM A units, which exhibits a standard deviation of 0.078% of the mean uranium concentration. Isotopic analysis of the uranium from three units, by means of thermal ionization mass spectrometry with a special, internal-standard procedure, indicated that the uranium isotopy is uniform among the pellets with a composition corresponding to 0.1115 ± 0.0006 wt. % 234 U, 19.8336 ± 0.0059 wt. % 235 U, 0.1337 ± 0.0006 wt. % 236 U, and 79.9171 ± 0.0057 wt. % 238 U

Rapid Quantitation of Ascorbic and Folic Acids in SRM 3280 Multivitamin/Multielement Tablets using Flow-Injection Tandem Mass Spectrometry

Energy Technology Data Exchange (ETDEWEB)

Bhandari, Deepak [ORNL; Kertesz, Vilmos [ORNL; Van Berkel, Gary J [ORNL

2013-01-01

RATIONALE: Ascorbic acid (AA) and folic acid (FA) are water-soluble vitamins and are usually fortified in food and dietary supplements. For the safety of human health, proper intake of these vitamins is recommended. Improvement in the analysis time required for the quantitative determination of these vitamins in food and nutritional formulations is desired. METHODS: A simple and fast (~5 min) in-tube sample preparation was performed, independently for FA and AA, by mixing extraction solvent with a powdered sample aliquot followed by agitation, centrifugation, and filtration to recover an extract for analysis. Quantitative detection was achieved by flow-injection (1 L injection volume) electrospray ionization tandem mass spectrometry (ESI-MS/MS) in negative ion mode using the method of standard addition. RESULTS: Method of standard addition was employed for the quantitative estimation of each vitamin in a sample extract. At least 2 spiked and 1 non-spiked sample extract were injected in triplicate for each quantitative analysis. Given an injection-to-injection interval of approximately 2 min, about 18 min was required to complete the quantitative estimation of each vitamin. The concentration values obtained for the respective vitamins in the standard reference material (SRM) 3280 using this approach were within the statistical range of the certified values provided in the NIST Certificate of Analysis. The estimated limit of detections of FA and AA were 13 and 5.9 ng/g, respectively. CONCLUSIONS: Flow-injection ESI-MS/MS was successfully applied for the rapid quantitation of FA and AA in SRM 3280 multivitamin/multielement tablets.

Optimization of fly ash as sand replacement materials (SRM) in cement composites containing coconut fiber

Science.gov (United States)

Nadzri, N. I. M.; Jamaludin, S. B.; Mazlee, M. N.; Jamal, Z. A. Z.

2016-07-01

The need of utilizing industrial and agricultural wastes is very important to maintain sustainability. These wastes are often incorporated with cement composites to improve performances in term of physical and mechanical properties. This study presents the results of the investigation of the response of cement composites containing coconut fiber as reinforcement and fly ash use as substitution of sand at different hardening days. Hardening periods of time (7, 14 and 28 days) were selected to study the properties of cement composites. Optimization result showed that 20 wt. % of fly ash (FA) is a suitable material for sand replacement (SRM). Meanwhile 14 days of hardening period gave highest compressive strength (70.12 MPa) from the cement composite containing 9 wt. % of coconut fiber and fly ash. This strength was comparable with the cement without coconut fiber (74.19 MPa) after 28 days of curing.

Thin layer chromatography coupled with surface-enhanced Raman scattering as a facile method for on-site quantitative monitoring of chemical reactions.

Science.gov (United States)

Zhang, Zong-Mian; Liu, Jing-Fu; Liu, Rui; Sun, Jie-Fang; Wei, Guo-Hua

2014-08-05

By coupling surface-enhanced Raman spectroscopy (SERS) with thin layer chromatography (TLC), a facile and powerful method was developed for on-site monitoring the process of chemical reactions. Samples were preseparated on a TLC plate following a common TLC procedure, and then determined by SERS after fabricating a large-area, uniform SERS substrate on the TLC plate by spraying gold nanoparticles (AuNPs). Reproducible and strong SERS signals were obtained with substrates prepared by spraying 42-nm AuNPs at a density of 5.54 × 10(10) N/cm(2) on the TLC plate. The capacity of this TLC-SERS method was evaluated by monitoring a typical Suzuki coupling reaction of phenylboronic acid and 2-bromopyridine as a model. Results showed that this proposed method is able to identify reaction product that is invisible to the naked eye, and distinguish the reactant 2-bromopyridine and product 2-phenylpyridine, which showed almost the same retention factors (R(f)). Under the optimized conditions, the peak area of the characteristic Raman band (755 cm(-1)) of the product 2-phenylpyridine showed a good linear correlation with concentration in the range of 2-200 mg/L (R(2) = 0.9741), the estimated detection limit (1 mg/L 2-phenylpyridine) is much lower than the concentration of the chemicals in the common organic synthesis reaction system, and the product yield determined by the proposed TLC-SERS method agreed very well with that by UPLC-MS/MS. In addition, a new byproduct in the reaction system was found and identified through continuous Raman detection from the point of sample to the solvent front. This facile TLC-SERS method is quick, easy to handle, low-cost, sensitive, and can be exploited in on-site monitoring the processes of chemical reactions, as well as environmental and biological processes.

In situ loading of well-dispersed silver nanoparticles on nanocrystalline magnesium oxide for real-time monitoring of catalytic reactions by surface enhanced Raman spectroscopy.

Science.gov (United States)

Zhang, Kaige; Li, Gongke; Hu, Yuling

2015-10-28

The surface-enhanced Raman spectroscopy (SERS) technique is of great importance for insight into the transient reaction intermediates and mechanistic pathways involved in heterogeneously catalyzed chemical reactions under actual reaction conditions, especially in water. Herein, we demonstrate a facile method for in situ synthesis of nanocrystalline magnesium oxide-Ag(0) (nano MgO-Ag(0)) hybrid nanomaterials with dispersed Ag nanoparticles (Ag NPs) on the surface of nanocrystalline magnesium oxide (nano MgO) via Sn(2+) linkage and reduction. As a benefit from the synergy effect of nano MgO and Ag NPs, the nano MgO-Ag(0) exhibited both excellent SERS and catalytic activities for the reduction of 4-nitrothiophenol in the presence of NaBH4. The nano MgO-Ag(0) was used for real-time monitoring of the catalytic reaction process of 4-nitrothiophenol to 4-aminothiophenol in an aqueous medium by observing the SERS signals of the reactant, intermediate and final products. The intrinsic reaction kinetics and reaction mechanism of this reaction were also investigated. This SERS-based synergy technique provides a novel approach for quantitative in situ monitoring of catalytic chemical reaction processes.

Monitoring environmental pollution by ko-INAA for environmental protection in Indonesia

International Nuclear Information System (INIS)

Sutisna; Saryati; Yusuf, Saeful; Rina, Theresia; Suryani, Rina

2007-01-01

Regarding to the 2005-2007FNCA program decided, the NAA technique based on the k o -method has been used to determine a concentration of pollutant as function of time and location. This program carries out to monitor a pollutant in the marine environmental sample. Marine samples of sediment, seawater and a clamp, as well as, a green oyster collected from a selected location at north of Banten province and the Bay of Jakarta. Sampling have been carried out twice a year. For background, same sample have been collected at the sampling point located at south-west of Banten. Sediment and biota sample were prepared for NAA determination, meanwhile seawater have been prepared for polarographic measurement. Marine Sediment and biota samples, as well as flux monitor, have been irradiated at a rabbit system facility of RSG GA Siwabessy reactor with a thermal neutron flux of about 2.6.10 +17 n.m -2 .s -1 . Identification of (n, γ) reaction product has been done using a high resolution HPGe detector coupled to a multichannel analyzer. Analysis of γ-ray emitted by activation product have been done using Hyperlab software, while the elemental quantitative analysis have been done by the k o -INAA procedure using k o -IAEA software. The analytical quality was controlled by use of certified reference material of NIST 2702 Marine Sediment, SRM NIST 1566b Oyster Tissue, crm NMIJ 7302a Sediment and CRM No. 9 Sargasso. As preliminary result, the numbers of interested elements in sediments samples were determined to be of about 20 and should be presented in this workshop. Some results of k o -INAA assessment will also be reported and discussed. (author)

The role of the Australian Adverse Drug Reactions Advisory Committee (ADRAC) in monitoring drug safety

International Nuclear Information System (INIS)

Boyd, Ian W.

2002-01-01

The Australian adverse drug reaction reporting system is acknowledged as one of the best in the world. Despite its small population of less than 20 million people, Australia's current ADR reporting rate of over 12000 reports per year places it in the top few nations in terms of reports per capita. The ADRAC program has been in operation for over 30 years. Australia was a founding member of the WHO International Drug Monitoring Programme which commenced in 1968 and currently there are about 153000 reports in the ADRAC database. Reports from health professionals have uncovered a number of significant safety problems over the years. Of particular importance are flucloxacillin-induced hepatitis, amoxycillin/clavulanate-induced hepatitis, and the association of cystitis with tiaprofenic acid. The number and quality of the reports has allowed an understanding of the characteristics of the reactions and, using ADRAC reporters as a major source of cases, case-control studies have been completed which have identified risk factors. ADRAC's review of Australian reports has highlighted many important associations that have been disseminated through the Australian Adverse Drug Reactions Bulletin

Adverse drug reaction monitoring of newer oral anti diabetic drugs – a pharmacovigilance perspective

Directory of Open Access Journals (Sweden)

Ankita Bhattacharjee

2016-04-01

Full Text Available Objective: To monitor and evaluate adverse drug reactions (ADRs of newer oral anti-diabetic drugs in type II diabetics by spontaneous/solicited ADR monitoring.Material and methods: Two hundred and thirty two diabetic patients on newer oral antidiabetic drugs were evaluated prospectively in a cross-sectional study over a period of eighteen months. All patients were followed up for ADRs which were evaluated for incidence, frequency, severity and causality. ADR severity was graded according to University of Virginia Health System Adverse Drug Reaction Reporting program criteria and causality assessment was done using WHO-UMC scale.Results: 190 out of 232 patients (42 patients lost to follow up were evaluated. ADRs were observed in 34 cases (17.9%. Most common ADRs were gastrointestinal (44.2% followed by musculoskeletal (17.6%, metabolic (14.7%, infections (5.9% and others (17.6%. The maximal frequency of ADRs was seen with sitagliptin (6.4% followed by vildagliptin(3.8%, saxagliptin(2.7%, saroglitazar(2.1%, linagliptin(1.6%, canagliflozin(1.6%. 25(73.5%, 8(23.5% and 1(3% ADRs were mild, moderate and severe respectively. 24(70% ADRs were classified as possible, 9(27% probable and 1(3% unlikely on causality assessment. Conclusion: Newer oral antidiabetic drugs like gliptins and SGLT-2 inhibitors have potential to cause ADRs. Gastro-intestinal, musculoskeletal, metabolic were most common ADRs. Active pharmacovigilance should be carried out for risk identification and management. 

Quantitative analysis of oxytetracycline and its impurities by LC-MS-MS

DEFF Research Database (Denmark)

Lykkeberg, Anne Kruse; Halling-Sørensen, Bent; Cornett, Claus

2004-01-01

A liquid chromatographic-tandem mass spectrometric method using an Xterra MS C(18) chromatographic column ( 100 mm x 2.1 mm i.d., 3.5microm) that allows complete separation of oxytetracycline (OTC) and the impurities: 4-epi-oxytetracycline (EOTC), tetracycline (TC), 4-epi-tetracycline (ETC), 2......-acetyl-2-decarboxamido-oxytetracycline (ADOTC), alpha-apo-oxytetracycline (alpha-AOTC) and beta-apo-oxytetracycline (beta-AOTC) was developed. Gradient elution was used and calibration curves were obtained using the scan mode selected reaction monitoring (SRM). Acceptable correlations were obtained...

Targeted mass spectrometry analysis of neutrophil-derived proteins released during sepsis progression

DEFF Research Database (Denmark)

Malmström, E; Davidova, A; Mörgelin, M

2014-01-01

systemic stimulation an immediate increase of neutrophil-borne proteins can be observed into the circulation of sepsis patients. We applied a combination of mass spectrometry (MS) based approaches, LC-MS/MS and selected reaction monitoring (SRM), to characterise and quantify the neutrophil proteome......Early diagnosis of severe infectious diseases is essential for timely implementation of lifesaving therapies. In a search for novel biomarkers in sepsis diagnosis we focused on polymorphonuclear neutrophils (PMNs). Notably, PMNs have their protein cargo readily stored in granules and following...

Identifying Understudied Nuclear Reactions by Text-mining the EXFOR Experimental Nuclear Reaction Library

Energy Technology Data Exchange (ETDEWEB)

Hirdt, J.A. [Department of Mathematics and Computer Science, St. Joseph' s College, Patchogue, NY 11772 (United States); Brown, D.A., E-mail: dbrown@bnl.gov [National Nuclear Data Center, Brookhaven National Laboratory, Upton, NY 11973-5000 (United States)

2016-01-15

The EXFOR library contains the largest collection of experimental nuclear reaction data available as well as the data's bibliographic information and experimental details. We text-mined the REACTION and MONITOR fields of the ENTRYs in the EXFOR library in order to identify understudied reactions and quantities. Using the results of the text-mining, we created an undirected graph from the EXFOR datasets with each graph node representing a single reaction and quantity and graph links representing the various types of connections between these reactions and quantities. This graph is an abstract representation of the connections in EXFOR, similar to graphs of social networks, authorship networks, etc. We use various graph theoretical tools to identify important yet understudied reactions and quantities in EXFOR. Although we identified a few cross sections relevant for shielding applications and isotope production, mostly we identified charged particle fluence monitor cross sections. As a side effect of this work, we learn that our abstract graph is typical of other real-world graphs.

Identifying Understudied Nuclear Reactions by Text-mining the EXFOR Experimental Nuclear Reaction Library

International Nuclear Information System (INIS)

Hirdt, J.A.; Brown, D.A.

2016-01-01

The EXFOR library contains the largest collection of experimental nuclear reaction data available as well as the data's bibliographic information and experimental details. We text-mined the REACTION and MONITOR fields of the ENTRYs in the EXFOR library in order to identify understudied reactions and quantities. Using the results of the text-mining, we created an undirected graph from the EXFOR datasets with each graph node representing a single reaction and quantity and graph links representing the various types of connections between these reactions and quantities. This graph is an abstract representation of the connections in EXFOR, similar to graphs of social networks, authorship networks, etc. We use various graph theoretical tools to identify important yet understudied reactions and quantities in EXFOR. Although we identified a few cross sections relevant for shielding applications and isotope production, mostly we identified charged particle fluence monitor cross sections. As a side effect of this work, we learn that our abstract graph is typical of other real-world graphs.

Development of a method based on inductively coupled plasma-dynamic reaction cell-mass spectrometry for the simultaneous determination of phosphorus, calcium and strontium in bone and dental tissue

International Nuclear Information System (INIS)

De Muynck, David; Vanhaecke, Frank

2009-01-01

A method, based on the use of a quadrupole-based inductively coupled plasma-mass spectrometry instrument equipped with a quadrupole-based collision/reaction cell (dynamic reaction cell, DRC), was developed for the simultaneous determination of phosphorus, calcium and strontium in bone and dental (enamel and dentine) tissue. The use of NH 3 , introduced at a gas flow rate of 0.8 mL min -1 in the dynamic reaction cell, combined with a rejection parameter q (RPq) setting of 0.65, allows interference-free determination of calcium via its low-abundant isotopes 42 Ca, 43 Ca and 44 Ca, and of strontium via its isotopes 86 Sr and 88 Sr that are freed from overlap due to the occurrence of ArCa + and/or Ca 2 + ions. Also the determination of phosphorus ( 31 P, mono-isotopic) was shown to be achievable using the same dynamic reaction cell operating conditions. The bone certified reference materials NIST SRM 1400 Bone Ash and NIST SRM 1486 Bone Meal were used for validation of the measurement protocol that was shown capable of providing accurate and reproducible results. Detection limits of P, Ca and Sr in dental tissue digests were established as 3 μg L -1 for P, 2 μg L -1 for Ca and 0.2 μg L -1 for Sr. This method can be used to simultaneously (i) evaluate the impact of diagenesis on the elemental and isotopic composition of buried skeletal tissue via its Ca/P ratio and (ii) determine its Sr concentration. The measurement protocol was demonstrated as fit-for-purpose by the analysis of a set of teeth of archaeological interest for their Ca/P ratio and Sr concentration.

New method for monitoring nitric oxide in vivo using microdialysis sampling and chemiluminescence reaction

Science.gov (United States)

Yao, Dachun; Evmiridis, Nick P.; Zhou, Yikai; Xu, Shunqing; Zhou, Huarong

2001-09-01

A new method employing a combination of micro dialysis sampling and chemiluminescence reaction was developed to monitor nitric oxide (NO) in vivo. A special probe was designed with an interference-free membrane to achieve a very high selectivity for NO. High sensitivity was achieved by optimizing the working system and improving the NO sampling time. This system was used in vivo to monitor blood and brain tissue in rats and rabbits. We have established that this system is sensitive enough to detect variations in NO production in difference physiological state. The system can detect NO in the linear range of 5nM-1(mu) M, with a detection limit of 1nM, and real NO concentrations in our experimental animals were found to be in the range of 1-5 nM or even less. Finally, the effects of body temperature, NO donors, Viagra, NO activators, NO cofactors, NO interference were investigated carefully in different physiological situations.

Characterization of human myotubes from type 2 diabetic and non-diabetic subjects using complementary quantitative mass spectrometric methods

DEFF Research Database (Denmark)

Thingholm, Tine E; Bak, Steffen; Beck-Nielsen, Henning

2011-01-01

2 diabetes. Several abnormalities have been identified in skeletal muscle from type 2 diabetic subjects, however, the exact molecular mechanisms leading to the diabetic phenotype has still not been found. Here we present a large-scale study in which we combine a quantitative proteomic discovery...... strategy using iTRAQ and a label-free study with a targeted quantitative proteomic approach using selected reaction monitoring (SRM) to identify, quantify and validate changes in protein abundance between human myotubes obtained from non-diabetic lean, non-diabetic obese and type 2 diabetic subjects...

Key role of temperature monitoring in interpretation of microwave effect on transesterification and esterification reactions for biodiesel production.

Science.gov (United States)

Mazubert, Alex; Taylor, Cameron; Aubin, Joelle; Poux, Martine

2014-06-01

Microwave effects have been quantified, comparing activation energies and pre-exponential factors to those obtained in a conventionally-heated reactor for biodiesel production from waste cooking oils via transesterification and esterification reactions. Several publications report an enhancement of biodiesel production using microwaves, however recent reviews highlight poor temperature measurements in microwave reactors give misleading reaction performances. Operating conditions have therefore been carefully chosen to investigate non-thermal microwave effects alone. Temperature is monitored by an optical fiber sensor, which is more accurate than infrared sensors. For the transesterification reaction, the activation energy is 37.1kJ/mol (20.1-54.2kJ/mol) in the microwave-heated reactor compared with 31.6kJ/mol (14.6-48.7kJ/mol) in the conventionally-heated reactor. For the esterification reaction, the activation energy is 45.4kJ/mol (31.8-58.9kJ/mol) for the microwave-heated reactor compared with 56.1kJ/mol (55.7-56.4kJ/mol) for conventionally-heated reactor. The results confirm the absence of non-thermal microwave effects for homogenous-catalyzed reactions. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pinus roxburghii plant needles as a three-season biomonitor for elemental air pollution monitoring along roadside

Energy Technology Data Exchange (ETDEWEB)

Daud, Muhammad; Wasim, Mohammad; Khalid, Nasir; Waheed, Shahida [Pakistan Institute of Nuclear Science and Technology, Islamabad (Pakistan). Chemistry Div.

2015-07-01

The present study deals with the determination of 36 elements in Pinus roxburghii plant needles to assess their potential as biomonitor for elemental air pollution monitoring. The elemental quantification was made by employing Instrumental Neutron Activation Analysis (INAA) and Atomic Absorption Spectrometric (AAS) techniques. The needles of Pinus roxburghii were collected in spring, summer and winter seasons from various sites in Islamabad. The method validation was performed by analyzing two certified reference materials i.e., Citrus leaves - NIST-SRM-1572 and IAEA-Soil-7. Pollution level was assessed by using three indicators: enrichment factor, pollution load index and average toxic element concentration. The results indicated that the needles of Pinus roxburghii plant had potential to monitor the extent of air pollution in the vicinity of high traffic areas.

Reference Cross Sections for Charged-particle Monitor Reactions

Czech Academy of Sciences Publication Activity Database

Hermanne, A.; Ignatyuk, A. V.; Capote, R.; Carlson, B. V.; Engle, J. W.; Kellett, M. A.; Kibédi, T.; Kim, G.; Kondev, F. G.; Hussain, M.; Lebeda, Ondřej; Luca, A.; Nagai, Y.; Naik, H.; Nichols, A. L.; Nortier, F. M.; Suryanarayana, S. V.; Takacs, S.; Tarkanyi, F. T.; Verpelli, M.

2018-01-01

Roč. 148, SI (2018), s. 338-382 ISSN 0090-3752 Institutional support: RVO:61389005 Keywords : deuteron induced reactions * proton induced reactions * cross sections Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders OBOR OECD: Nuclear physics Impact factor: 1.146, year: 2016

A Demonstration of Concrete Structural Health Monitoring Framework for Degradation due to Alkali-Silica Reaction

Energy Technology Data Exchange (ETDEWEB)

Mahadevan, Sankaran [Idaho National Lab. (INL), Idaho Falls, ID (United States); Agarwal, Vivek [Idaho National Lab. (INL), Idaho Falls, ID (United States); Neal, Kyle [Idaho National Lab. (INL), Idaho Falls, ID (United States); Nath, Paromita [Idaho National Lab. (INL), Idaho Falls, ID (United States); Bao, Yanqing [Idaho National Lab. (INL), Idaho Falls, ID (United States); Cai, Guowei [Idaho National Lab. (INL), Idaho Falls, ID (United States); Orme, Peter [Idaho National Lab. (INL), Idaho Falls, ID (United States); Adams, Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kosson, David [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-04-01

Assessment and management of aging concrete structures in nuclear power plants require a more systematic approach than simple reliance on existing code margins of safety. Structural health monitoring of concrete structures aims to understand the current health condition of a structure based on heterogeneous measurements to produce high-confidence actionable information regarding structural integrity that supports operational and maintenance decisions. This ongoing research project is seeking to develop a probabilistic framework for health diagnosis and prognosis of aging concrete structures in a nuclear power plant that is subjected to physical, chemical, environment, and mechanical degradation. The proposed framework consists of four elements: monitoring, data analytics, uncertainty quantification and prognosis. This report focuses on degradation caused by ASR (alkali-silica reaction). Controlled specimens were prepared to develop accelerated ASR degradation. Different monitoring techniques – thermography, digital image correlation (DIC), mechanical deformation measurements, nonlinear impact resonance acoustic spectroscopy (NIRAS), and vibro-acoustic modulation (VAM) -- were used to detect the damage caused by ASR. Heterogeneous data from the multiple techniques was used for damage diagnosis and prognosis, and quantification of the associated uncertainty using a Bayesian network approach. Additionally, MapReduce technique has been demonstrated with synthetic data. This technique can be used in future to handle large amounts of observation data obtained from the online monitoring of realistic structures.

First WHO/IFCC International Reference Reagent for Lipoprotein(a) for Immunoassay--Lp(a) SRM 2B.

Science.gov (United States)

Dati, Francesco; Tate, Jillian R; Marcovina, Santica M; Steinmetz, Armin

2004-01-01

Lipoprotein(a) is an important predictor of cardiovascular disease risk. The lack of internationally accepted standardization has impeded the broad application of this lipoprotein in laboratory medicine. The International Federation of Clinical Chemistry and Laboratory Medicine (IFCC), through its Working Group on Lipoprotein(a) and together with research institutions and several diagnostic companies, have succeeded in developing an international reference material that is intended for the transfer of a lipoprotein(a) concentration to manufacturers' master calibrators. IFCC SRM 2B has recently been accepted by the WHO Expert Committee on Biological Standardization as the 'First WHO/IFCC International Reference Reagent for Lipoprotein(a) for Immunoassay'. The assigned unitage of 0.1071 nanomoles of lipoprotein(a) per vial is traceable to the consensus reference method for lipoprotein(a) and will enable conformity by diagnostic companies to the European Union's Directive on In vitro Diagnostic Medical Devices for the metrological traceability of calibrator materials.

Studies on 222Rn concentration in ground water using smart radon monitor and assessment of the radiation dose to the population of Mysuru city

International Nuclear Information System (INIS)

Chandrashekara, M.S.; Pruthvi Rani, K.S.

2017-01-01

Radioactive elements originate from the earth's crust and make their way into air, water, food and eventually in to the living system. Even though 75% of the Earth's surface is covered by water, only about 0.3 % of the total water on the Earth is available for public use. The ground water contains trace amounts of radioactive elements and these radionuclides contribute significant amount of dose to living beings, through intake of water into the human body. Radon dissolved in water is released into air when it is used for cooking, drinking, bathing and washing purposes. Exposure of population to higher concentrations of radon and its progeny for a long time causes occurrence of lung cancer and pathological effects like respiratory functional changes. Radon is a main source of ionizing radiation of natural origin and the studies on radon concentrations in drinking water are of importance. A systematic study of 226 Ra and 222 Rn concentration in the drinking water samples was carried out in Mysuru city. The concentration of 226 Ra and 222 Rn was estimated in water samples using emanometry method employing scintillation cells and alpha counting system. The 222 Rn concentration in water was also measured using a Smart Radon Monitor (SRM) for comparison of the results. SRM is a technologically advanced real time, portable, radon monitor developed at BARC, Mumbai

Process spectroscopy in microemulsions—setup and multi-spectral approach for reaction monitoring of a homogeneous hydroformylation process

Science.gov (United States)

Meyer, K.; Ruiken, J.-P.; Illner, M.; Paul, A.; Müller, D.; Esche, E.; Wozny, G.; Maiwald, M.

2017-03-01

Reaction monitoring in disperse systems, such as emulsions, is of significant technical importance in various disciplines like biotechnological engineering, chemical industry, food science, and a growing number other technical fields. These systems pose several challenges when it comes to process analytics, such as heterogeneity of mixtures, changes in optical behavior, and low optical activity. Concerning this, online nuclear magnetic resonance (NMR) spectroscopy is a powerful technique for process monitoring in complex reaction mixtures due to its unique direct comparison abilities, while at the same time being non-invasive and independent of optical properties of the sample. In this study the applicability of online-spectroscopic methods on the homogeneously catalyzed hydroformylation system of 1-dodecene to tridecanal is investigated, which is operated in a mini-plant scale at Technische Universität Berlin. The design of a laboratory setup for process-like calibration experiments is presented, including a 500 MHz online NMR spectrometer, a benchtop NMR device with 43 MHz proton frequency as well as two Raman probes and a flow cell assembly for an ultraviolet and visible light (UV/VIS) spectrometer. Results of high-resolution online NMR spectroscopy are shown and technical as well as process-specific problems observed during the measurements are discussed.

Electrocatalytic oxygen reduction and hydrogen evolution reactions on phthalocyanine modified electrodes: Electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric monitoring

Energy Technology Data Exchange (ETDEWEB)

Koca, Atif, E-mail: akoca@eng.marmara.edu.tr [Department of Chemical Engineering, Faculty of Engineering, Marmara University, Goeztepe, 34722 Istanbul (Turkey); Kalkan, Ayfer; Bayir, Zehra Altuntas [Department of Chemistry, Technical University of Istanbul, Maslak, 34469 Istanbul (Turkey)

2011-06-30

Highlights: > Electrochemical and in situ spectroelectrochemical characterizations of the metallophthalocyanines were performed. > The presence of O{sub 2} influences both oxygen reduction reaction and the electrochemical behaviors of the complexes. > Homogeneous catalytic ORR process occurs via an 'inner sphere' chemical catalysis process. > CoPc and CuPc coated on a glassy carbon electrode decrease the overpotential of the working electrode for H{sup +} reduction. - Abstract: This study describes electrochemical, in situ spectroelectrochemical, and in situ electrocolorimetric monitoring of the electrocatalytic reduction of molecular oxygen and hydronium ion on the phthalocyanine-modified electrodes. For this purpose, electrochemical and in situ spectroelectrochemical characterizations of the metallophthalocyanines (MPc) bearing tetrakis-[4-((4'-trifluoromethyl)phenoxy)phenoxy] groups were performed. While CoPc gives both metal-based and ring-based redox processes, H{sub 2}Pc, ZnPc and CuPc show only ring-based electron transfer processes. In situ electrocolorimetric method was applied to investigate the color of the electrogenerated anionic and cationic forms of the complexes. The presence of O{sub 2} in the electrolyte system influences both oxygen reduction reaction and the electrochemical and spectral behaviors of the complexes, which indicate electrocatalytic activity of the complexes for the oxygen reduction reaction. Perchloric acid titrations monitored by voltammetry represent possible electrocatalytic activities of the complexes for hydrogen evolution reaction. CoPc and CuPc coated on a glassy carbon electrode decrease the overpotential of the working electrode for H{sup +} reduction. The nature of the metal center changes the electrocatalytic activities for hydrogen evolution reaction in aqueous solution. Although CuPc has an inactive metal center, its electrocatalytic activity is recorded more than CoPc for H{sup +} reduction in aqueous

Detection of Legionella by quantitative-polymerase chain reaction (qPCR) for monitoring and risk assessment

DEFF Research Database (Denmark)

Krøjgaard, Louise H.; Krogfelt, Karen A.; Albrechtsen, Hans-Jorgen

2011-01-01

Background: Culture and quantitative polymerase chain reaction (qPCR) assays for the detection of Legionella were compared on samples from a residential area before and after two interventions. A total of 84 samples were collected from shower hoses and taps as first flush samples and at constant...... temperature. Samples were grouped according to the origin of the sample, a) circulation water b) water from empty apartments c) water from shower hoses. The aims were to investigate the usefulness of qPCR compared to culture for monitoring remedial actions for elimination of Legionella bacteria and as a tool...

Prioritizing Popular Proteins in Liver Cancer: Remodelling One-Carbon Metabolism.

Science.gov (United States)

Mora, María Isabel; Molina, Manuela; Odriozola, Leticia; Elortza, Félix; Mato, José María; Sitek, Barbara; Zhang, Pumin; He, Fuchu; Latasa, María Uxue; Ávila, Matías Antonio; Corrales, Fernando José

2017-12-01

Primary liver cancer (HCC) is recognized as the fifth most common neoplasm and the second leading cause of cancer death worldwide. Most risk factors are known, and the molecular pathogenesis has been widely studied in the past decade; however, the underlying molecular mechanisms remain to be unveiled, as they will facilitate the definition of novel biomarkers and clinical targets for more effective patient management. We utilize the B/D-HPP popular protein strategy. We report a list of popular proteins that have been highly cocited with the expression "liver cancer". Several enzymes highlight the known metabolic remodeling of liver cancer cells, four of which participate in one-carbon metabolism. This pathway is central to the maintenance of differentiated hepatocytes, as it is considered the connection between intermediate metabolism and epigenetic regulation. We designed a targeted selective reaction monitoring (SRM) method to follow up one-carbon metabolism adaptation in mouse HCC and in regenerating liver following exposure to CCl 4 . This method allows systematic monitoring of one-carbon metabolism and could prove useful in the follow-up of HCC and of chronically liver-diseased patients (cirrhosis) at risk of HCC. The SRM data are available via ProteomeXchange in PASSEL (PASS01060).

High performance Solid Rocket Motor (SRM) submerged nozzle/combustion cavity flowfield assessment

Science.gov (United States)

Freeman, J. A.; Chan, J. S.; Murph, J. E.; Xiques, K. E.

1987-01-01

Two and three dimensional internal flowfield solutions for critical points in the Space Shuttle solid rocket booster burn time were developed using the Lockheed Huntsville GIM/PAID Navier-Stokes solvers. These perfect gas, viscous solutions for the high performance motor characterize the flow in the aft segment and nozzle of the booster. Two dimensional axisymmetric solutions were developed at t = 20 and t = 85 sec motor burn times. The t = 85 sec solution indicates that the aft segment forward inhibitor stub produces vortices with are shed and convected downwards. A three dimensional 3.5 deg gimbaled nozzle flowfield solution was developed for the aft segment and nozzle at t = 9 sec motor burn time. This perfect gas, viscous analysis, provided a steady state solution for the core region and the flow through the nozzle, but indicated that unsteady flow exists in the region under the nozzle nose and near the flexible boot and nozzle/case joint. The flow in the nozzle/case joint region is characterized by low magnitude pressure waves which travel in the circumferential direction. From the two and three dimensional flowfield calculations presented it can be concluded that there is no evidence from these results that steady state gas dynamics is the primary mechanism resulting in the nozzle pocketing erosion experienced on SRM nozzles 8A or 17B. The steady state flowfield results indicate pocketing erosion is not directly initiated by a steady state gas dynamics phenomenon.

Evaluation of neutron monitor cross sections for 59Co(n,x)56,57,58Co, 52,54,56Mn, 59Fe reactions

International Nuclear Information System (INIS)

Yu Baosheng; Shen Qingbiao; Cai Dunjiu

1996-01-01

The neutron monitor cross sections for 59 Co(n,x) 56,57,58 Co, 52,54,56 Mn, 59 Fe reactions were evaluated based on recent experimental data and theoretical calculations from threshold energy to 100 MeV. (8 figs.)

Porous polycarbene-bearing membrane actuator for ultrasensitive weak-acid detection and real-time chemical reaction monitoring.

Science.gov (United States)

Sun, Jian-Ke; Zhang, Weiyi; Guterman, Ryan; Lin, Hui-Juan; Yuan, Jiayin

2018-04-30

Soft actuators with integration of ultrasensitivity and capability of simultaneous interaction with multiple stimuli through an entire event ask for a high level of structure complexity, adaptability, and/or multi-responsiveness, which is a great challenge. Here, we develop a porous polycarbene-bearing membrane actuator built up from ionic complexation between a poly(ionic liquid) and trimesic acid (TA). The actuator features two concurrent structure gradients, i.e., an electrostatic complexation (EC) degree and a density distribution of a carbene-NH 3 adduct (CNA) along the membrane cross-section. The membrane actuator performs the highest sensitivity among the state-of-the-art soft proton actuators toward acetic acid at 10 -6  mol L -1 (M) level in aqueous media. Through competing actuation of the two gradients, it is capable of monitoring an entire process of proton-involved chemical reactions that comprise multiple stimuli and operational steps. The present achievement constitutes a significant step toward real-life application of soft actuators in chemical sensing and reaction technology.

Integrated Solid-Phase Extraction-Capillary Liquid Chromatography (speLC) Interfaced to ESI-MS/MS for Fast Characterization and Quantification of Protein and Proteomes

DEFF Research Database (Denmark)

Falkenby, Lasse Gaarde; Such-Sanmartín, Gerard; Larsen, Martin Røssel

2014-01-01

min speLC-MS/MS experiment. Analysis by selected reaction monitoring by speLC-SRM-MS/MS of distinct peptides derived from the blood proteins IGF1, IGF2, IBP2, and IBP3 demonstrated protein quantification with CV values below 10% across 96 replicates. The speLC-MS/MS system is ideally suited for fast......The high peptide sequencing speed provided by modern hybrid tandem mass spectrometers enables the utilization of fast liquid chromatographic (LC) separation techniques. We present a robust solid-phase extraction/capillary LC system (speLC) for 5-10 min separation of semicomplex peptide mixtures...

Redox Reaction in Silicate Melts Monitored by ''Static'' In-Situ Fe K-Edge XANES up to 1180 deg. C

International Nuclear Information System (INIS)

Wilke, Max; Partzsch, Georg M.; Welter, Edmund; Farges, Francois

2007-01-01

A new experimental setup to measure in-situ kinetics of redox reactions in silicate melts is presented. To study the progress of the Fe-redox reaction, the variation of the signal is recorded at an energy, where the difference between the spectra of the oxidized and reduced Fe in the melt is largest (''static XANES''). To control the redox conditions, the gas atmosphere could be changed between to types of gases using computer-controlled valves (N2:H2 and air, respectively). In this way, a number of reduction/oxidation cycles can be monitored in-situ and continuously. Applied at the Fe K-edge in molten silicates, we obtained a set of high quality data, which includes the very first steps of the redox reaction. An Avrami-type equation is used to investigate rate-controlling parameters for the iron oxidation/reduction kinetics for two melts (basaltic and Na trisilicate) for temperatures up to 1180 deg. C

LC-ESI/MS/MS method for rapid screening and confirmation of 44 exogenous anabolic steroids in human urine.

Science.gov (United States)

Jeon, Byoung Wook; Yoo, Hye Hyun; Jeong, Eun Sook; Kim, Ho Jun; Jin, Changbae; Kim, Dong Hyun; Lee, Jaeick

2011-09-01

A sensitive and rapid method based on liquid chromatography-triple-quadrupole tandem mass spectrometry (LC-MS/MS) with electrospray ionization (ESI) has been developed and validated for the screening and confirmation of 44 exogenous anabolic steroids (29 parent steroids and 15 metabolites) in human urine. The method involves an enzymatic hydrolysis, liquid-liquid extraction, and detection by LC-MS/MS. A triple-quadrupole mass spectrometer was operated in positive ESI mode with selected reaction monitoring (SRM) mode for the screening and product ion scan mode for the confirmation. The protonated molecular ions were used as precursor ions for the SRM analysis and product ion scan. The intraday and interday precisions of the target analytes at concentrations of the minimum required performance levels for the screening were 2-14% and 2-15%, respectively. The limits of detection for the screening and confirmation method were 0.1-10 ng/mL and 0.2-10 ng/mL, respectively, for 44 steroids. This method was successfully applied to analysis of urine samples from suspected anabolic steroid abusers.

A Mathematical Model for the Multiphase Transport and Reaction Kinetics in a Ladle with Bottom Powder Injection

Science.gov (United States)

Lou, Wentao; Zhu, Miaoyong

2017-12-01

A computation fluid dynamics-population balance model-simultaneous reaction model (CFD-PBM-SRM) coupled model has been proposed to study the multiphase flow behavior and refining reaction kinetics in a ladle with bottom powder injection, and some new and important phenomena and mechanisms are presented. For the multiphase flow behavior, the effects of bubbly plume flow, powder particle motion, particle-particle collision and growth, particle-bubble collision and adhesion, and powder particle removal into top slag are considered. For the reaction kinetics, the mechanisms of multicomponent simultaneous reactions, including Al, S, Si, Mn, Fe, and O, at the multi-interface, including top slag-liquid steel interface, air-liquid steel interface, powder droplet-liquid steel interface, and bubble-liquid steel interface, are presented, and the effect of sulfur solubility in the powder droplet on the desulfurization is also taken into account. Model validation is carried out using hot tests in a 2-t induction furnace with bottom powder injection. The result shows that the powder particles gradually disperse in the entire furnace; in the vicinity of the bottom slot plugs, the desulfurization product CaS is liquid phase, while in the upper region of the furnace, the desulfurization product CaS is solid phase. The predicted sulfur contents by the present model agree well with the measured data in the 2-t furnace with bottom powder injection.

The application of multiple reaction monitoring to assess ApoA-I methionine oxidations in diabetes and cardiovascular disease

Directory of Open Access Journals (Sweden)

Hussein N. Yassine

2014-12-01

Full Text Available The oxidative modification of apolipoprotein A-I’s methionine148 (M148 is associated with defective HDL function in vitro. Multiple reaction monitoring (MRM is a mass spectrometric technique that can be used to quantitate post-translational modifications. In this study, we developed an MRM assay to monitor the abundance ratio of the peptide containing oxidized M148 to the native peptide in ApoA-I. Measurement of the oxidized-to-unoxidized-M148 ratio was reproducible (CV < 5%. The extent of methionine M148 oxidation in the HDL of healthy controls, and type 2 diabetic participants with and without prior cardiovascular events (CVD were then examined. The results suggest a significant increase in the relative ratio of the peptide containing oxidized M148 to the unmodified peptide in the HDL of participants with diabetes and CVD (p < 0.001, compared to participants without CVD. Monitoring the abundance ratio of the peptides containing oxidized and unoxidized M148 by MRM provides a means of examining the relationship between M148 oxidation and vascular complications in CVD.

Adverse drug reactions monitoring of psychotropic drugs: a tertiary care centre study

Directory of Open Access Journals (Sweden)

Hemendra Singh

2017-06-01

Full Text Available Background: Many new psychotropic drugs/ agents have been developed and found to be effective in the treatment of psychiatric disorders. However, these drugs also exhibit adverse drug reactions (ADRs which may affect compliance in psychiatric patients. Hence the present study was aimed at monitoring and assessing ADRs caused by psychotropic drugs. Methods: A hospital based prospective observational study was carried out in the psychiatry outpatient department of a tertiary care teaching hospital for the duration of six months. Two hundred and two patients were included in the study and ADRs were documented using a predesigned data collection form. The causality assessment was carried out as per the criteria of both the World Health Organization- Uppsala Monitoring Centre (WHO-UMC and Naranjo scale. Severity and predictability assessment of ADRs were also performed. Results: A total of 106 ADRs were observed during the study period with majority of them occurring in 25-35 years of age group (40.56%. Weight gain (18.86% followed by sedation (16.03% and insomnia (11.32% were found to be the commonest ADRs. Risperidone (19.8% and escitalopram (12.3% were the drugs responsible for majority of the ADRs. Causality assessment showed that most of ADRs were possible and probable. 94.33% of ADRs were found to be mild and 89% of them were predictable. Conclusion: A wide range of ADRs affecting central nervous and metabolic systems were reported with psychotropic drugs. The study findings necessitate the need for an active pharmacovigilance programme for the safe and effective use of psychotropics.

Differences between Drug-Induced and Contrast Media-Induced Adverse Reactions Based on Spontaneously Reported Adverse Drug Reactions.

Science.gov (United States)

Ryu, JiHyeon; Lee, HeeYoung; Suh, JinUk; Yang, MyungSuk; Kang, WonKu; Kim, EunYoung

2015-01-01

We analyzed differences between spontaneously reported drug-induced (not including contrast media) and contrast media-induced adverse reactions. Adverse drug reactions reported by an in-hospital pharmacovigilance center (St. Mary's teaching hospital, Daejeon, Korea) from 2010-2012 were classified as drug-induced or contrast media-induced. Clinical patterns, frequency, causality, severity, Schumock and Thornton's preventability, and type A/B reactions were recorded. The trends among causality tools measuring drug and contrast-induced adverse reactions were analyzed. Of 1,335 reports, 636 drug-induced and contrast media-induced adverse reactions were identified. The prevalence of spontaneously reported adverse drug reaction-related admissions revealed a suspected adverse drug reaction-reporting rate of 20.9/100,000 (inpatient, 0.021%) and 3.9/100,000 (outpatients, 0.004%). The most common adverse drug reaction-associated drug classes included nervous system agents and anti-infectives. Dermatological and gastrointestinal adverse drug reactions were most frequently and similarly reported between drug and contrast media-induced adverse reactions. Compared to contrast media-induced adverse reactions, drug-induced adverse reactions were milder, more likely to be preventable (9.8% vs. 1.1%, p contrast media-induced adverse reactions (56.6%, p = 0.066). Causality patterns differed between the two adverse reaction classes. The World Health Organization-Uppsala Monitoring Centre causality evaluation and Naranjo algorithm results significantly differed from those of the Korean algorithm version II (p contrast media-induced adverse reactions. The World Health Organization-Uppsala Monitoring Centre and Naranjo algorithm causality evaluation afforded similar results.

Summary Report of the First Research Coordination Meeting on Nuclear Data for Charged-Particle Monitor Reactions and Medical Isotope Production

International Nuclear Information System (INIS)

Nichols, Alan L.; Noy, Roberto Capote

2013-02-01

A summary is given of the first IAEA research coordination meeting on ''Nuclear Data for Charged-particle Monitor Reactions and Medical Isotope Production'. Participants reassessed and reviewed the requirements for both cross-section and decay data, based on the earlier findings of three IAEA consultants' meetings (High-precision beta-intensity measurements and evaluations for specific PET radioisotopes, INDC(NDS)-0535, December 2008; Improvements in charged-particle monitor reactions and nuclear data for medical isotope production, INDC(NDS)-0591, September 2011; Intermediate-term nuclear data needs for medical applications: cross sections and decay data, INDC(NDS)-0596, September 2011). While significant emphasis was placed on the needs defined in IAEA report INDC(NDS)-0591, a limited number of relevant items and issues were also considered from the other two technical meetings. Recommendations focused on cross-section studies for a reasonably wide range of targets and projectiles, along with decay data measurements and evaluations for specific radionuclides. Individual presentations and discussions are described in this report, along with listings of the agreed work packages to be undertaken by the participants of the coordinated research project. (author)

Experimental cross-sections of deuteron-induced reaction on Y-89 up to 20 MeV; comparison of Ti-nat(d,x)V-48 and Al-27(d,x)Na-24 monitor reactions

Czech Academy of Sciences Publication Activity Database

Lebeda, Ondřej; Štursa, Jan; Ráliš, Jan

2015-01-01

Roč. 360, OCT (2015), s. 118-128 ISSN 0168-583X R&D Projects: GA MŠk LM2011019 Institutional support: RVO:61389005 Keywords : deuteron-induced nuclear reactions * excitation functions * Na, Mg, Sc, V, Sr, Y and Zr radioisotopes * deuteron beam monitors * U-120M cyclotron Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 1.389, year: 2015

UNE-EN ISO/IEC 17025:2005-accredited method for the determination of pesticide residues in fruit and vegetable samples by LC-MS/MS.

Science.gov (United States)

Camino-Sánchez, F J; Zafra-Gómez, A; Oliver-Rodríguez, B; Ballesteros, O; Navalón, A; Crovetto, G; Vílchez, J L

2010-11-01

A rapid, simple and sensitive multi-residue method was developed and validated for the simultaneous quantification and confirmation of 69 pesticides in fruit and vegetables using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The samples were extracted following the quick, easy, cheap, effective, rugged and safe method known as QuEChERS. Mass spectrometric conditions were individually optimised for each analyte in order to achieve maximum sensitivity in multiple reaction monitoring (MRM) mode. Using the developed chromatographic conditions, 69 pesticides can be separated in less than 17 min. Two selected reaction monitoring (SRM) assays were used for each pesticide to obtain simultaneous quantification and identification in one run. With this method in SRM mode, more than 150 pesticides can be analysed and quantified, but their confirmation is not possible in all cases according to the European regulations on pesticide residues. Nine common representative matrices (zucchini, melon, cucumber, watermelon, tomato, garlic, eggplant, lettuce and pepper) were selected to investigate the effect of different matrices on recovery and precision. Mean recoveries ranged from 70% to 120%, with relative standard deviations (RSDs) lower than 20% for all the pesticides. The proposed method was applied to the analysis of more than 2000 vegetable samples from the extensive greenhouse cultivation in the province of Almeria, Spain, during one year. The methodology combines the advantages of both QuEChERS and LC-MS/MS producing a very rapid, sensitive, accurate and reliable procedure that can be applied in routine analytical laboratories. The method was validated and accredited according to UNE-EN-ISO/IEC 17025:2005 international standard (accreditation number 278/LE1027).

Reaction Order Ambiguity in Integrated Rate Plots

Science.gov (United States)

Lee, Joe

2008-01-01

Integrated rate plots are frequently used in reaction kinetics to determine orders of reactions. It is often emphasised, when using this methodology in practice, that it is necessary to monitor the reaction to a substantial fraction of completion for these plots to yield unambiguous orders. The present article gives a theoretical and statistical…

Quantification of mutant SPOP proteins in prostate cancer using mass spectrometry-based targeted proteomics

Energy Technology Data Exchange (ETDEWEB)

Wang, Hui; Barbieri, Christopher E.; He, Jintang; Gao, Yuqian; Shi, Tujin; Wu, Chaochao; Schepmoes, Athena A.; Fillmore, Thomas L.; Chae, Sung-Suk; Huang, Dennis; Mosquera, Juan Miguel; Qian, Wei-Jun; Smith, Richard D.; Srivastava, Sudhir; Kagan, Jacob; Camp, David G.; Rodland, Karin D.; Rubin, Mark A.; Liu, Tao

2017-08-15

Speckle-type POZ protein (SPOP) is an E3 ubiquitin ligase adaptor protein that functions as a potential tumor suppressor, and SPOP mutations have been identified in ~10% of human prostate cancers. However, it remains unclear if mutant SPOP proteins can be utilized as biomarkers for early detection, diagnosis, prognosis or targeted therapy of prostate cancer. Moreover, the SPOP mutation sites are distributed in a relatively short region where multiple lysine residues, posing significant challenges for bottom-up proteomics analysis of the SPOP mutations. To address this issue, PRISM (high-pressure, high-resolution separations coupled with intelligent selection and multiplexing)-SRM (selected reaction monitoring) mass spectrometry assays have been developed for quantifying wild-type SPOP protein and 11 prostate cancer-derived SPOP mutations. Despite inherent limitations due to amino acid sequence constraints, all the PRISM-SRM assays developed using Arg-C digestion showed a linear dynamic range of at least two orders of magnitude, with limits of quantification range from 0.1 to 1 fmol/μg of total protein in the cell lysate. Applying these SRM assays to analyze HEK293T cells with and without expression of the three most frequent SPOP mutations in prostate cancer (Y87N, F102C or F133V) led to confident detection of all three SPOP mutations in corresponding positive cell lines but not in the negative cell lines. Expression of the F133V mutation and wild-type SPOP was at much lower levels compared to that of F102C and Y87N mutations; however, at present it is unknown if this also affects the activity of the SPOP protein. In summary, PRISM-SRM enables multiplexed, isoform-specific detection of mutant SPOP proteins in cell lysates, which holds great potential in biomarker development for prostate cancer.

Monitoring of an esterification reaction by on-line direct liquid sampling mass spectrometry and in-line mid infrared spectrometry with an attenuated total reflectance probe

International Nuclear Information System (INIS)

Owen, Andrew W.; McAulay, Edith A.J.; Nordon, Alison; Littlejohn, David; Lynch, Thomas P.; Lancaster, J. Steven; Wright, Robert G.

2014-01-01

Highlights: • High efficiency thermal vaporiser designed and used for on-line reaction monitoring. • Concentration profiles of all reactants and products obtained from mass spectra. • By-product formed from the presence of an impurity detected by MS but not MIR. • Mass spectrometry can detect trace and bulk components unlike molecular spectrometry. - Abstract: A specially designed thermal vaporiser was used with a process mass spectrometer designed for gas analysis to monitor the esterification of butan-1-ol and acetic anhydride. The reaction was conducted at two scales: in a 150 mL flask and a 1 L jacketed batch reactor, with liquid delivery flow rates to the vaporiser of 0.1 and 1.0 mL min −1 , respectively. Mass spectrometry measurements were made at selected ion masses, and classical least squares multivariate linear regression was used to produce concentration profiles for the reactants, products and catalyst. The extent of reaction was obtained from the butyl acetate profile and found to be 83% and 76% at 40 °C and 20 °C, respectively, at the 1 L scale. Reactions in the 1 L reactor were also monitored by in-line mid-infrared (MIR) spectrometry; off-line gas chromatography (GC) was used as a reference technique when building partial least squares (PLS) multivariate calibration models for prediction of butyl acetate concentrations from the MIR spectra. In validation experiments, good agreement was achieved between the concentration of butyl acetate obtained from in-line MIR spectra and off-line GC. In the initial few minutes of the reaction the profiles for butyl acetate derived from on-line direct liquid sampling mass spectrometry (DLSMS) differed from those of in-line MIR spectrometry owing to the 2 min transfer time between the reactor and mass spectrometer. As the reaction proceeded, however, the difference between the concentration profiles became less noticeable. DLSMS had advantages over in-line MIR spectrometry as it was easier to generate

Generic DART-MS platform for monitoring the on-demand continuous-flow production of pharmaceuticals: Advancing the quantitative protocol for caffeates in microfluidic biocatalysis.

Science.gov (United States)

Xu, Yan; Zhang, Dong-Yang; Meng, Xiang-Yun; Liu, Xi; Sheng, Sheng; Wu, Guo-Hua; Wang, Jun; Wu, Fu-An

2017-04-15

Today, continuous processing is regarded as an effective on-demand production technique of pharmaceuticals. Homemade microreactors packed with immobilized lipase under continuous-flow conditions were first applied to tailor the production of high-value caffeic acid phenethyl ester (CAPE) from methyl caffeate (MC) and 2-phenylethanol (PE) in cyclohexane via transesterification; however, this method is challenging due to the lack of a rapid platform for monitoring caffeates in microfluidic biocatalysis. The reactants were directly analyzed using Direct Analysis in Real Time Mass Spectrometry (DART-MS), and the corresponding ionization parameters were investigated. Special ions produced from MC (parent ion m/z 192.87 and product ion m/z 133.44) and CAPE (parent ion m/z 282.93 and product ion m/z 178.87) were determined using DART-MS 2 in the negative ion mode. The peak areas of the select reaction monitoring (SRM) signals were calculated to develop the standard curves for quantitative analyses of the concentration. Reasonable linear regression equations of MC and CAPE were obtained in the range of 3.125-50.000mg/L, with linear coefficients (R 2 ) of 0.9515 and 0.9973, limits of detection (LOD) of 0.005 and 0.003mg/L, limits of quantification (LOQ) of 0.02 and 0.01mg/L, and recovery ranges of 92.50-97.11% and 90.11-97.60%, respectively. The results using DART-MS 2 were in good agreement with those using conventional High-Performance Liquid Chromatography with a UV detector (HPLC-UV) and were successfully applied to monitor the kinetics constants and mass transfer coefficients in a continuous-flow packed bed microreactor. Thus, the DART-MS 2 method is an efficient tool for analyzing caffeates in microfluidic biocatalysis with limited sample preparation and short operating time. Copyright © 2017 Elsevier B.V. All rights reserved.

Direct calibration of GC/MS systems using SRM (Standard Reference Material) gas cylinders. Project report, January 1984-August 1985

International Nuclear Information System (INIS)

Byrd, G.D.; Richie, K.L.; Sniegoski, L.T.; White, E.

1985-10-01

A cryogenic trapping system has been developed for use in calibrating GC/MS systems for the analysis of volatile organic compounds. This system provides for direct Standard Reference Material (SRM) traceability on data generated on gaseous samples. The cryogenic trap is a coil of stainless steel tubing immersed in a cryogen to trap and preconcentrate organic species present in a gaseous sample. The trap also contains a heated injection port for the addition of isotopically labeled compounds for use in isotope dilution measurements. The first part of this research is concerned with the development of IDMS as an independent method for the quantification of analytes in gaseous samples to be used as standards. Results are presented for the determination of bromobenzene in nitrogen at nominal concentrations of 1 and 25 ppb. In the second part of the research, a calibration curve method was developed for using these standards in auditing the performance of GC/MS systems

MONITORING POTENTIAL DRUG INTERACTIONS AND REACTIONS VIA NETWORK ANALYSIS OF INSTAGRAM USER TIMELINES.

Science.gov (United States)

Correia, Rion Brattig; Li, Lang; Rocha, Luis M

2016-01-01

Much recent research aims to identify evidence for Drug-Drug Interactions (DDI) and Adverse Drug reactions (ADR) from the biomedical scientific literature. In addition to this "Bibliome", the universe of social media provides a very promising source of large-scale data that can help identify DDI and ADR in ways that have not been hitherto possible. Given the large number of users, analysis of social media data may be useful to identify under-reported, population-level pathology associated with DDI, thus further contributing to improvements in population health. Moreover, tapping into this data allows us to infer drug interactions with natural products-including cannabis-which constitute an array of DDI very poorly explored by biomedical research thus far. Our goal is to determine the potential of Instagram for public health monitoring and surveillance for DDI, ADR, and behavioral pathology at large. Most social media analysis focuses on Twitter and Facebook, but Instagram is an increasingly important platform, especially among teens, with unrestricted access of public posts, high availability of posts with geolocation coordinates, and images to supplement textual analysis. Using drug, symptom, and natural product dictionaries for identification of the various types of DDI and ADR evidence, we have collected close to 7000 user timelines spanning from October 2010 to June 2015.We report on 1) the development of a monitoring tool to easily observe user-level timelines associated with drug and symptom terms of interest, and 2) population-level behavior via the analysis of co-occurrence networks computed from user timelines at three different scales: monthly, weekly, and daily occurrences. Analysis of these networks further reveals 3) drug and symptom direct and indirect associations with greater support in user timelines, as well as 4) clusters of symptoms and drugs revealed by the collective behavior of the observed population. This demonstrates that Instagram

The quantitative monitoring of mechanochemical reaction between solid L-tartaric acid and sodium carbonate monohydrate by terahertz spectroscopy

Science.gov (United States)

Liu, Xiaohong; Liu, Guifeng; Zhao, Hongwei; Zhang, Zengyang; Wei, Yongbo; Liu, Min; Wen, Wen; Zhou, Xingtai

2011-11-01

The solid-state reaction of chiral tartaric acid and alkali carbonate was studied by terahertz time-domain spectroscopy (THz-TDS). The sodium tartrate dihydrate was synthesized with high efficiency by mechanical grinding in the solid-state without waste that is particularly sustainable and environmentally benign. Distinct THz absorptions were observed for reactants and products. It indicates that THz spectroscopy is sensitive to different materials and crystal structures. The characteristic THz absorption peak at 1.09 THz of L (+)-Tartaric acid was selected for quantitative analysis. The reaction kinetics could be expressed by the Second-order equation and the Jander equation, which is consistent with a three-dimensional diffusion mechanism. The combination of multi-techniques including synchrotron radiation X-ray powder diffraction (SRXRPD), Fourier transform infrared (FT-IR) and scanning electron microscopy (SEM) was used to investigate the grinding process and presented supporting evidences. The results demonstrate that THz spectroscopy technique has great potential applications in process monitoring and analysis in pharmaceutical and chemical synthesis industry.

COPD Exacerbation Biomarkers Validated Using Multiple Reaction Monitoring Mass Spectrometry.

Directory of Open Access Journals (Sweden)

Janice M Leung

Full Text Available Acute exacerbations of chronic obstructive pulmonary disease (AECOPD result in considerable morbidity and mortality. However, there are no objective biomarkers to diagnose AECOPD.We used multiple reaction monitoring mass spectrometry to quantify 129 distinct proteins in plasma samples from patients with COPD. This analytical approach was first performed in a biomarker cohort of patients hospitalized with AECOPD (Cohort A, n = 72. Proteins differentially expressed between AECOPD and convalescent states were chosen using a false discovery rate 1.2. Protein selection and classifier building were performed using an elastic net logistic regression model. The performance of the biomarker panel was then tested in two independent AECOPD cohorts (Cohort B, n = 37, and Cohort C, n = 109 using leave-pair-out cross-validation methods.Five proteins were identified distinguishing AECOPD and convalescent states in Cohort A. Biomarker scores derived from this model were significantly higher during AECOPD than in the convalescent state in the discovery cohort (p<0.001. The receiver operating characteristic cross-validation area under the curve (CV-AUC statistic was 0.73 in Cohort A, while in the replication cohorts the CV-AUC was 0.77 for Cohort B and 0.79 for Cohort C.A panel of five biomarkers shows promise in distinguishing AECOPD from convalescence and may provide the basis for a clinical blood test to diagnose AECOPD. Further validation in larger cohorts is necessary for future clinical translation.

Data processing has major impact on the outcome of quantitative label-free LC-MS analysis.

Science.gov (United States)

Chawade, Aakash; Sandin, Marianne; Teleman, Johan; Malmström, Johan; Levander, Fredrik

2015-02-06

High-throughput multiplexed protein quantification using mass spectrometry is steadily increasing in popularity, with the two major techniques being data-dependent acquisition (DDA) and targeted acquisition using selected reaction monitoring (SRM). However, both techniques involve extensive data processing, which can be performed by a multitude of different software solutions. Analysis of quantitative LC-MS/MS data is mainly performed in three major steps: processing of raw data, normalization, and statistical analysis. To evaluate the impact of data processing steps, we developed two new benchmark data sets, one each for DDA and SRM, with samples consisting of a long-range dilution series of synthetic peptides spiked in a total cell protein digest. The generated data were processed by eight different software workflows and three postprocessing steps. The results show that the choice of the raw data processing software and the postprocessing steps play an important role in the final outcome. Also, the linear dynamic range of the DDA data could be extended by an order of magnitude through feature alignment and a charge state merging algorithm proposed here. Furthermore, the benchmark data sets are made publicly available for further benchmarking and software developments.

Surface chloride salt formation on Space Shuttle exhaust alumina

Science.gov (United States)

Cofer, W. R., III; Pellett, G. L.; Sebacher, D. I.; Wakelyn, N. T.

1984-01-01

Aluminum oxide samples from the exhaust of Space Shuttle launches STS-1, STS-4, STS-5, and STS-6 were collected from surfaces on or around the launch pad complex and chemically analyzed. The results indicate that the particulate solid-propellant rocket motor (SRM) alumina was heavily chlorided. Concentrations of water-soluble aluminum (III) ion were large, suggesting that the surface of the SRM alumina particles was rendered soluble by prior reactions with HCl and H2O in the SRM exhaust cloud. These results suggest that Space Shuttle exhaust alumina particles are good sites for nucleation and condensation of atmospheric water. Laboratory experiments conducted at 220 C suggest that partial surface chloriding of alumina may occur in hot Space Shuttle exhaust plumes.

Photochemical reaction monitoring by ultra-violet spectrophotometry.

Science.gov (United States)

Roig, B; Touraud, E; Thomas, O

2002-11-01

Within the framework of the monitoring of the trichloroacetylchloride (TCAC) photosynthesis, ultra-violet (UV) spectrophotometry is proposed as a simple and rapid tool allowing, in real time, the control of the process efficiency. A good correlation has been obtained between the results acquired by this alternative method and the standard gas chromatography.

Bridging the Gap: From Model Surfaces to Nanoparticle Analogs for Selective Oxidation and Steam Reforming of Methanol and Selective Hydrogenation Catalysis

Science.gov (United States)

Boucher, Matthew B.

Most industrial catalysts are very complex, comprising of non-uniform materials with varying structures, impurities, and interaction between the active metal and supporting substrate. A large portion of the ongoing research in heterogeneous catalysis focuses on understanding structure-function relationships in catalytic materials. In parallel, there is a large area of surface science research focused on studying model catalytic systems for which structural parameters can be tuned and measured with high precision. It is commonly argued, however, that these systems are oversimplified, and that observations made in model systems do not translate to robust catalysts operating in practical environments; this discontinuity is often referred to as a "gap." The focus of this thesis is to explore the mutual benefits of surface science and catalysis, or "bridge the gap," by studying two catalytic systems in both ultra-high vacuum (UHV) and near ambient-environments. The first reaction is the catalytic steam reforming of methanol (SRM) to hydrogen and carbon dioxide. The SRM reaction is a promising route for on-demand hydrogen production. For this catalytic system, the central hypothesis in this thesis is that a balance between redox capability and weak binding of reaction intermediates is necessary for high SRM activity and selectivity to carbon dioxide. As such, a new catalyst for the SRM reaction is developed which incorporates very small amounts of gold (liquid-phase, stirred-tank batch reactor under a hydrogen head pressure of approximately 7 bar. Palladium alloyed into the surface of otherwise inactive copper nanoparticles shows a marked improvement in selectivity when compared to monometallic palladium catalysts with the same metal loading. This effect is attributed hydrogen spillover onto the copper surface. In summary, the development of new, highly active and selective catalysts for the methanol steam reforming reaction and for the partial hydrogenation of alkynes

Lithium analysis using a double-sided silicon strip detector at LIBAF

Science.gov (United States)

De La Rosa, Nathaly; Kristiansson, Per; Nilsson, E. J. Charlotta; Ros, Linus; Elfman, Mikael; Pallon, Jan

2017-08-01

Quantification and mapping possibilities of lithium in geological material, by Nuclear Reaction Analysis (NRA), was evaluated at the Lund Ion Beam Analysis Facility (LIBAF). LiF and two Standard Reference Materials, (SRM 610 and SRM 612) were used in the investigation. The main part of the data was obtained at the beam energy 635 keV studying the high Q-value reaction 7Li(p, α)4He, but reaction yield and detection limits were also briefly investigated as a function of the energy. A double-sided silicon strip detector (DSSSD) was used to detect the α -particles emitted in the reaction in the backward direction. The combination of the high Q-value, a reasonably good cross-section and the possibility to use a high beam current have been demonstrated to allow for measurement of concentrations down below 50 ppm. Proton energies below 800 keV were demonstrated to be appropriate energies for extracting lithium in combination with boron analysis.

Radioactive phosphorylation of alcohols to monitor biocatalytic Diels-Alder reactions.

Directory of Open Access Journals (Sweden)

Alexander Nierth

Full Text Available Nature has efficiently adopted phosphorylation for numerous biological key processes, spanning from cell signaling to energy storage and transmission. For the bioorganic chemist the number of possible ways to attach a single phosphate for radioactive labeling is surprisingly small. Here we describe a very simple and fast one-pot synthesis to phosphorylate an alcohol with phosphoric acid using trichloroacetonitrile as activating agent. Using this procedure, we efficiently attached the radioactive phosphorus isotope (32P to an anthracene diene, which is a substrate for the Diels-Alderase ribozyme-an RNA sequence that catalyzes the eponymous reaction. We used the (32P-substrate for the measurement of RNA-catalyzed reaction kinetics of several dye-labeled ribozyme variants for which precise optical activity determination (UV/vis, fluorescence failed due to interference of the attached dyes. The reaction kinetics were analyzed by thin-layer chromatographic separation of the (32P-labeled reaction components and densitometric analysis of the substrate and product radioactivities, thereby allowing iterative optimization of the dye positions for future single-molecule studies. The phosphorylation strategy with trichloroacetonitrile may be applicable for labeling numerous other compounds that contain alcoholic hydroxyl groups.

In Situ Solid-State Reactions Monitored by X-ray Absorption Spectroscopy: Temperature-Induced Proton Transfer Leads to Chemical Shifts.

Science.gov (United States)

Stevens, Joanna S; Walczak, Monika; Jaye, Cherno; Fischer, Daniel A

2016-10-24

The dramatic colour and phase alteration with the solid-state, temperature-dependent reaction between squaric acid and 4,4'-bipyridine has been probed in situ with X-ray absorption spectroscopy. The electronic and chemical sensitivity to the local atomic environment through chemical shifts in the near-edge X-ray absorption fine structure (NEXAFS) revealed proton transfer from the acid to the bipyridine base through the change in nitrogen protonation state in the high-temperature form. Direct detection of proton transfer coupled with structural analysis elucidates the nature of the solid-state process, with intermolecular proton transfer occurring along an acid-base chain followed by a domino effect to the subsequent acid-base chains, leading to the rapid migration along the length of the crystal. NEXAFS thereby conveys the ability to monitor the nature of solid-state chemical reactions in situ, without the need for a priori information or long-range order. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Multiple reaction monitoring assay based on conventional liquid chromatography and electrospray ionization for simultaneous monitoring of multiple cerebrospinal fluid biomarker candidates for Alzheimer's disease.

Science.gov (United States)

Choi, Yong Seok; Lee, Kelvin H

2016-03-01

Alzheimer's disease (AD) is the most common type of dementia, but early and accurate diagnosis remains challenging. Previously, a panel of cerebrospinal fluid (CSF) biomarker candidates distinguishing AD and non-AD CSF accurately (>90 %) was reported. Furthermore, a multiple reaction monitoring (MRM) assay based on nano liquid chromatography tandem mass spectrometry (nLC-MS/MS) was developed to help validate putative AD CSF biomarker candidates including proteins from the panel. Despite the good performance of the MRM assay, wide acceptance may be challenging because of limited availability of nLC-MS/MS systems in laboratories. Thus, here, a new MRM assay based on conventional LC-MS/MS is presented. This method monitors 16 peptides representing 16 (of 23) biomarker candidates that belonged to the previous AD CSF panel. A 30-times more concentrated sample than the sample used for the previous study was loaded onto a high capacity trap column, and all 16 MRM transitions showed good linearity (average R(2) = 0.966), intra-day reproducibility (average coefficient of variance (CV) = 4.78 %), and inter-day reproducibility (average CV = 9.85 %). The present method has several advantages such as a shorter analysis time, no possibility of target variability, and no need for an internal standard.

C.A.R.S. monitor of fragmentation and secondary reactions during U.V. laser induced decomposition of benzene

International Nuclear Information System (INIS)

Fantoni, R.; Giorgi, M.; Moliterni, A.G.G.; Lipinska-Kalita, K.E.

1992-01-01

Among the different types of non-linear Raman spectroscopies, vibrational CARS (Coherent AntiStokes Raman Scattering, probing Raman active vibrational modes) has proved to be a valuable on-line technique in the study of laser induced processes involving gas phase reactants, such as the deposition of thin films or synthesis of ultrafine powders. The application of lasers in total decomposition (mineralisation) of gas-phase pollutants has been considered, and test experiments have been started on benzene as a precursor of a large family of aromatic pollutants. This paper reports on the use of a broad-band CARS to monitor, on-line, the laser induced dissociation of benzene at 266 nm. The electronically excited C 2 produced during the process was detected by RECARS (Resonantly Enhanced CARS) in the visible region. The laser induced primary decomposition and secondary reaction were studied under collisional conditions upon the addition of inert (N 2 ) and reactive (O 2 ) partners. Reaction intermediates produced in electronically excited states were detected by time resolved spontaneous emission spectroscopy performed with the same set-up in the absence of probe lasers

MONITORING POTENTIAL DRUG INTERACTIONS AND REACTIONS VIA NETWORK ANALYSIS OF INSTAGRAM USER TIMELINES

Science.gov (United States)

CORREIA, RION BRATTIG; LI, LANG; ROCHA, LUIS M.

2015-01-01

Much recent research aims to identify evidence for Drug-Drug Interactions (DDI) and Adverse Drug reactions (ADR) from the biomedical scientific literature. In addition to this “Bibliome”, the universe of social media provides a very promising source of large-scale data that can help identify DDI and ADR in ways that have not been hitherto possible. Given the large number of users, analysis of social media data may be useful to identify under-reported, population-level pathology associated with DDI, thus further contributing to improvements in population health. Moreover, tapping into this data allows us to infer drug interactions with natural products—including cannabis—which constitute an array of DDI very poorly explored by biomedical research thus far. Our goal is to determine the potential of Instagram for public health monitoring and surveillance for DDI, ADR, and behavioral pathology at large. Most social media analysis focuses on Twitter and Facebook, but Instagram is an increasingly important platform, especially among teens, with unrestricted access of public posts, high availability of posts with geolocation coordinates, and images to supplement textual analysis. Using drug, symptom, and natural product dictionaries for identification of the various types of DDI and ADR evidence, we have collected close to 7000 user timelines spanning from October 2010 to June 2015. We report on 1) the development of a monitoring tool to easily observe user-level timelines associated with drug and symptom terms of interest, and 2) population-level behavior via the analysis of co-occurrence networks computed from user timelines at three different scales: monthly, weekly, and daily occurrences. Analysis of these networks further reveals 3) drug and symptom direct and indirect associations with greater support in user timelines, as well as 4) clusters of symptoms and drugs revealed by the collective behavior of the observed population. This demonstrates that

Multiple reaction monitoring targeted LC-MS analysis of potential cell death marker proteins for increased bioprocess control.

Science.gov (United States)

Albrecht, Simone; Kaisermayer, Christian; Reinhart, David; Ambrose, Monica; Kunert, Renate; Lindeberg, Anna; Bones, Jonathan

2018-05-01

The monitoring of protein biomarkers for the early prediction of cell stress and death is a valuable tool for process characterization and efficient biomanufacturing control. A representative set of six proteins, namely GPDH, PRDX1, LGALS1, CFL1, TAGLN2 and MDH, which were identified in a previous CHO-K1 cell death model using discovery LC-MS E was translated into a targeted liquid chromatography multiple reaction monitoring mass spectrometry (LC-MRM-MS) platform and verified. The universality of the markers was confirmed in a cell growth model for which three Chinese hamster ovary host cell lines (CHO-K1, CHO-S, CHO-DG44) were grown in batch culture in two different types of basal media. LC-MRM-MS was also applied to spent media (n = 39) from four perfusion biomanufacturing series. Stable isotope-labelled peptide analogues and a stable isotope-labelled monoclonal antibody were used for improved protein quantitation and simultaneous monitoring of the workflow reproducibility. Significant increases in protein concentrations were observed for all viability marker proteins upon increased dead cell numbers and allowed for discrimination of spent media with dead cell densities below and above 1 × 10 6  dead cells/mL which highlights the potential of the selected viability marker proteins in bioprocess control. Graphical abstract Overview of the LC-MRM-MS workflow for the determination of proteomic markers in conditioned media from the bioreactor that correlate with CHO cell death.

Evaluation of neutron monitor cross sections for {sup 59}Co(n,x){sup 56,57,58}Co, {sup 52,54,56}Mn, {sup 59}Fe reactions

Energy Technology Data Exchange (ETDEWEB)

Baosheng, Yu; Qingbiao, Shen; Dunjiu, Cai [Chinese Nuclear Data Center, Beijing, BJ (China)

1996-06-01

The neutron monitor cross sections for {sup 59}Co(n,x){sup 56,57,58}Co, {sup 52,54,56}Mn, {sup 59}Fe reactions were evaluated based on recent experimental data and theoretical calculations from threshold energy to 100 MeV. (8 figs.).

Spectrally Resolved and Functional Super-resolution Microscopy via Ultrahigh-Throughput Single-Molecule Spectroscopy.

Science.gov (United States)

Yan, Rui; Moon, Seonah; Kenny, Samuel J; Xu, Ke

2018-03-20

SMLM was next utilized to achieve f-SRM. By encoding functional information into the spectral responses of environment-sensing fluorescent probes, f-SRM transcends the structural information provided by typical SRM techniques and reveals the spatiotemporal distribution of physicochemical parameters with single-molecule sensitivity and nanoscale spatial resolution. As one example, by employing the solvatochromic dye Nile Red to sense local chemical polarity, we revealed nanoscale heterogeneity in the membranes of live mammalian cells. This enabled us to unveil substantial polarity differences between the plasma membrane and the membranes of nanoscale intracellular organelles, a result we determined to be due to differences in local cholesterol levels. With the addition of cholesterol or cholera toxin, we further observed the formation of low-polarity, raftlike nanodomains in the plasma membrane. In another study, we generalized SR-SMLM to fluorogenic single-molecule reactions. As a wide-field technique, SR-SMLM readily captures the emission spectra of individual product fluorescent molecules that are stochastically produced from nonfluorescent reactants at random locations over large sample areas, and therefore, it provides the unique possibility to spectrally identify and characterize single product molecules in a high-throughput fashion. Using the ring-opening reaction of a photochromic spiropyran as an example, we demonstrated that the capability to resolve the emission spectra of single product molecules could unveil rich, multipath reaction pathways. In summary, by integrating the spatial, temporal, and spectral dimensions of single-molecule fluorescence, SR-SMLM and f-SRM add rich spectral and functional dimensions to SRM and thus open up new ways of probing biological and chemical systems at the single-molecule and nanoscale levels.

Liquid-Crystalline Ionic Liquids as Ordered Reaction Media for the Diels-Alder Reaction.

Science.gov (United States)

Bruce, Duncan W; Gao, Yanan; Canongia Lopes, José Nuno; Shimizu, Karina; Slattery, John M

2016-11-02

Liquid-crystalline ionic liquids (LCILs) are ordered materials that have untapped potential to be used as reaction media for synthetic chemistry. This paper investigates the potential for the ordered structures of LCILs to influence the stereochemical outcome of the Diels-Alder reaction between cyclopentadiene and methyl acrylate. The ratio of endo- to exo-product from this reaction was monitored for a range of ionic liquids (ILs) and LCILs. Comparison of the endo:exo ratios in these reactions as a function of cation, anion and liquid crystallinity of the reaction media, allowed for the effects of liquid crystallinity to be distinguished from anion effects or cation alkyl chain length effects. These data strongly suggest that the proportion of exo-product increases as the reaction media is changed from an isotropic IL to a LCIL. A detailed molecular dynamics (MD) study suggests that this effect is related to different hydrogen bonding interactions between the reaction media and the exo- and endo-transition states in solvents with layered, smectic ordering compared to those that are isotropic. © 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

26kDa endochitinase from barley seeds: real-time monitoring of the enzymatic reaction and substrate binding experiments using electrospray ionization mass spectrometry

DEFF Research Database (Denmark)

Dennhart, Nicole; Weigang, Linda M M; Fujiwara, Maho

2009-01-01

A 26 kDa endochitinase from barley seeds was enzymatically characterized exclusively by electrospray ionization mass spectrometry (ESI-MS). At first, oligosaccharide hydrolysis catalyzed by the barley chitinase was monitored in real-time by ESI-MS. The reaction time-course obtained by ESI......-MS monitoring was found to be consistent with the data obtained earlier by HPLC, and the quantitative profile was successfully simulated by kinetic modeling of the enzymatic hydrolysis. It is obvious that the real-time monitoring method by ESI-MS allows a faster and cheaper determination of the chitinase...... of the enzymatic activity in E67Q is definitely caused by a point mutation of Glu67 but not due to partial unfolding of the mutated enzyme. Finally, association constants of enzyme-oligosaccharide complexes were calculated from Scatchard plots obtained by mass spectra. The binding free energy values obtained for E...

Supplier relationship management leverages intellectual capital for increased competitive advantage

Directory of Open Access Journals (Sweden)

C. R. Van Zyl

2005-12-01

Full Text Available The main purpose of this article is to demonstrate how supplier relationship management (SRM enables the capture and creation of intellectual capital, thereby attaining and sustaining a strategic competitive advantage and increasing supply chain profitability. In order to achieve this purpose, a large part of the article is devoted to exploring the relatively new and unknown field of SRM. It is shown that an organisation must possess a thorough understanding of good supplier characteristics and of the drivers, benefits and requirements for the successful implementation of SRM, in order to enable that organisation to leverage their supplier relationships to ensure the capture of supplier expertise, patents, experiences etc. (i.e. their intellectual capital. The article then explores how the integration of technology in SRM applications can improve the efficiency of supplier collaboration and intellectual capital capture and creation. It is then demonstrated how efficient and collaborative supplier relationships improve supply chain profitability and competitiveness. Lastly, the article explores the implementation pitfalls and trends of SRM that must be constantly considered and monitored by an organisation in order to continually capture and create intellectual capital and reap the full benefits of SRM. This exploration involved an examination of contemporary literature, theories and business cases and subsequently revealed that SRM is a vital discipline/philosophy that must be implemented by any organisation wishing to achieve greater supply chain efficiency and competitiveness. This competitiveness can only be achieved through the mutual unlocking, sharing and leveraging of intellectual capital.

The application of selected radionuclides for monitoring of the D-D reactions produced by dense plasma-focus device.

Science.gov (United States)

Jednorog, S; Szydlowski, A; Bienkowska, B; Prokopowicz, R

The dense plasma focus (DPF) device-DPF-1000U which is operated at the Institute of Plasma Physics and Laser Microfusion is the largest that type plasma experiment in the world. The plasma that is formed in large plasma experiments is characterized by vast numbers of parameters. All of them need to be monitored. A neutron activation method occupies a high position among others plasma diagnostic methods. The above method is off-line, remote, and an integrated one. The plasma which has enough temperature to bring about nuclear fusion reactions is always a strong source of neutrons that leave the reactions area and take along energy and important information on plasma parameters and properties as well. Silver as activated material is used as an effective way of neutrons measurement, especially when they are emitted in the form of short pulses like as it happens from the plasma produced in Dense Plasma-Focus devices. Other elements such as beryllium and yttrium are newly introduced and currently tested at the Institute of Plasma Physics and Laser Microfusion to use them in suitable activation neutron detectors. Some specially designed massive indium samples have been recently adopted for angular neutrons distribution measurements (vertical and horizontal) and have been used in the recent plasma experiment conducted on the DPF-1000U device. This choice was substantiated by relatively long half-lives of the neutron induced isotopes and the threshold character of the 115 In(n,n') 115m In nuclear reaction.

A quantitative evaluation of the public response to climate engineering

Science.gov (United States)

Wright, Malcolm J.; Teagle, Damon A. H.; Feetham, Pamela M.

2014-02-01

Atmospheric greenhouse gas concentrations continue to increase, with CO2 passing 400 parts per million in May 2013. To avoid severe climate change and the attendant economic and social dislocation, existing energy efficiency and emissions control initiatives may need support from some form of climate engineering. As climate engineering will be controversial, there is a pressing need to inform the public and understand their concerns before policy decisions are taken. So far, engagement has been exploratory, small-scale or technique-specific. We depart from past research to draw on the associative methods used by corporations to evaluate brands. A systematic, quantitative and comparative approach for evaluating public reaction to climate engineering is developed. Its application reveals that the overall public evaluation of climate engineering is negative. Where there are positive associations they favour carbon dioxide removal (CDR) over solar radiation management (SRM) techniques. Therefore, as SRM techniques become more widely known they are more likely to elicit negative reactions. Two climate engineering techniques, enhanced weathering and cloud brightening, have indistinct concept images and so are less likely to draw public attention than other CDR or SRM techniques.

Charged particle cross-section database for medical radioisotope production: diagnostic radioisotopes and monitor reactions. Final report of a co-ordinated research project

International Nuclear Information System (INIS)

2001-05-01

Medical applications of nuclear radiation are of considerable interest to the IAEA. Cyclotrons and accelerators, available in recent years in an increasing number of countries, are being used for the production of radioisotopes for both diagnostic and therapeutic purposes. The physical basis of this production is described through interaction of charged particles, such as protons, deuterons and alphas, with matter. These processes have to be well understood in order to produce radioisotopes in an efficient and clean manner. In addition to medical radioisotope production, reactions with low energy charged particles are of primary importance for two major applications. Techniques of ion beam analysis use many specific reactions to identify material properties, and in nuclear astrophysics there is interest in numerous reaction rates to understand nucleosynthesis in the Universe. A large number of medically oriented cyclotrons have been running in North America, western Europe and Japan for more than two decades. In recent years, 30-40 MeV cyclotrons and smaller cyclotrons (E p < 20 MeV) have been installed in several countries. Although the production methods are well established, there are no evaluated and recommended nuclear data sets available. The need for standardization was thus imminent. This was pointed out at three IAEA meetings. Based on the recommendations made at these meetings, the IAEA decided to undertake and organize the Co-ordinated Research Project (CRP) on Development of Reference Charged Particle Cross-Section Database for Medical Radioisotope Production. The project was initiated in 1995. It focused on radioisotopes for diagnostic purposes and on the related beam monitor reactions in order to meet current needs. It constituted the first major international effort dedicated to standardization of nuclear data for radioisotope production. It covered the following areas: Compilation of data on the most important reactions for monitoring light ion

Parallel reaction monitoring on a Q Exactive mass spectrometer increases reproducibility of phosphopeptide detection in bacterial phosphoproteomics measurements.

Science.gov (United States)

Taumer, Christoph; Griesbaum, Lena; Kovacevic, Alen; Soufi, Boumediene; Nalpas, Nicolas C; Macek, Boris

2018-03-29

Increasing number of studies report the relevance of protein Ser/Thr/Tyr phosphorylation in bacterial physiology, yet the analysis of this type of modification in bacteria still presents a considerable challenge. Unlike in eukaryotes, where tens of thousands of phosphorylation events likely occupy more than two thirds of the proteome, the abundance of protein phosphorylation is much lower in bacteria. Even the state-of-the-art phosphopeptide enrichment protocols fail to remove the high background of abundant unmodified peptides, leading to low signal intensity and undersampling of phosphopeptide precursor ions in consecutive data-dependent MS runs. Consequently, large-scale bacterial phosphoproteomic datasets often suffer from poor reproducibility and a high number of missing values. Here we explore the application of parallel reaction monitoring (PRM) on a Q Exactive mass spectrometer in bacterial phosphoproteome analysis, focusing especially on run-to-run sampling reproducibility. In multiple measurements of identical phosphopeptide-enriched samples, we show that PRM outperforms data-dependent acquisition (DDA) in terms of detection frequency, reaching almost complete sampling efficiency, compared to 20% in DDA. We observe a similar trend over multiple heterogeneous phosphopeptide-enriched samples and conclude that PRM shows a great promise in bacterial phosphoproteomics analyses where reproducible detection and quantification of a relatively small set of phosphopeptides is desired. Bacterial phosphorylated peptides occur in low abundance compared to their unmodified counterparts, and are therefore rarely reproducibly detected in shotgun (DDA) proteomics measurements. Here we show that parallel reaction monitoring complements DDA analyses and makes detection of known, targeted phosphopeptides more reproducible. This will be of significance in replicated MS measurements that have a goal to reproducibly detect and quantify phosphopeptides of interest. Copyright �

Monitoring anti-TNF{alpha} treatment in RA: Responsiveness of magnetic resonance imaging and ultrasonography of the dominant wrist compared to conventional measures of disease activity and structural damage

DEFF Research Database (Denmark)

Haavardsholm, Espen A; Ostergaard, Mikkel; Hammer, Hilde Berner

2008-01-01

months. Responsiveness was assessed by standardized response means (SRM). Accepted thresholds were applied to classify responsiveness as trivial, low, moderate or good. RESULTS: MRI synovitis (SRM between -0.79 and -0.92) and the MRI total inflammation score comprising synovitis, tenosynovitis and bone...... marrow edema (SRM between -1.05 and -1.24) were highly responsive. Moderate to high responsiveness was found for MRI tenosynovitis and bone marrow edema, all the composite indices (DAS28, SDAI and CDAI) and the 28-swollen joint count. US displayed low to moderate responsiveness. The MRI erosion score...... was a composite measure comprising MRI synovitis, tenosynovitis and bone marrow edema, and this may be a promising outcome measure in clinical studies....

SIGNIFICANCE OF СD4+ Т-LYMPHOCYTE POPULATIONS MONITORING FOR DIAGNOSING AND FORECASTING OF ORGANISM REACTION ON TRANSPLANT

Directory of Open Access Journals (Sweden)

N. A. Onishchenko

2013-01-01

Full Text Available In this review article the necessity of adaptation and introduction into clinical practice of simultaneous monitoring of immune blood cells and cytokines in patients with grafted organs for a choice of individual tactic of immuno- suppressive therapy, determination of its efficiency and forecasting is proved. It is emphasized, that with the spe- cial attention it ought to concern to characteristic of CD4 + T-lymphocytes and to definition of an interrelation of their separate populations in peripheral blood (Treg, Th17, Tact memory cells – CD4+CD25hiCD127hiCD45RO since they are the basic participants of immune system reaction on grafts. 

Continuous monitoring of the zinc-phosphate acid-base cement setting reaction by proton nuclear magnetic relaxation

International Nuclear Information System (INIS)

Apih, T.; Lebar, A.; Pawlig, O.; Trettin, R.

2001-01-01

Proton nuclear magnetic relaxation is a well-established technique for continuous and non destructive monitoring of hydration of conventional Portland building cements. Here, we demonstrate the feasibility of nuclear magnetic resonance (NMR) monitoring of the setting reaction of zinc-phosphate acid-base dental cements, which harden in minutes as compared to days, as in the case of Portland cements. We compare the setting of cement powder (mainly, zinc oxide) prepared with clinically used aluminum-modified orthophosphoric acid solution with the setting of a model system where cement powder is mixed with pure orthophosphoric acid solution. In contrast to previously published NMR studies of setting Portland cements, where a decrease of spin-lattice relaxation time is attributed to enhanced relaxation at the growing internal surface, spin-lattice relaxation time T 1 increases during the set of clinically used zinc-phosphate cement. Comparison of these results with a detailed study of diffusion, viscosity, and magnetic-field dispersion of T 1 in pure and aluminum-modified orthophosphoric acid demonstrates that the increase of T 1 in the setting cement is connected with the increase of molecular mobility in the residual phosphoric acid solution. Although not taken into account so far, such effects may also significantly influence the relaxation times in setting Portland cements, particularly when admixtures with an effect on water viscosity are used. [copyright] 2001 American Institute of Physics

Electrochemical study of quinone redox cycling: A novel application of DNA-based biosensors for monitoring biochemical reactions.

Science.gov (United States)

Ensafi, Ali A; Jamei, Hamid Reza; Heydari-Bafrooei, Esmaeil; Rezaei, B

2016-10-01

This paper presents the results of an experimental investigation of voltammetric and impedimetric DNA-based biosensors for monitoring biological and chemical redox cycling reactions involving free radical intermediates. The concept is based on associating the amounts of radicals generated with the electrochemical signals produced, using differential pulse voltammetry (DPV) and electrochemical impedance spectroscopy (EIS). For this purpose, a pencil graphite electrode (PGE) modified with multiwall carbon nanotubes and poly-diallydimethlammonium chloride decorated with double stranded fish sperm DNA was prepared to detect DNA damage induced by the radicals generated from a redox cycling quinone (i.e., menadione (MD; 2-methyl-1,4-naphthoquinone)). Menadione was employed as a model compound to study the redox cycling of quinones. A direct relationship was found between free radical production and DNA damage. The relationship between MD-induced DNA damage and free radical generation was investigated in an attempt to identify the possible mechanism(s) involved in the action of MD. Results showed that DPV and EIS were appropriate, simple and inexpensive techniques for the quantitative and qualitative comparisons of different reducing reagents. These techniques may be recommended for monitoring DNA damages and investigating the mechanisms involved in the production of redox cycling compounds. Copyright © 2016 Elsevier B.V. All rights reserved.

Monitoring mass transport in heterogeneously catalyzed reactions by field-gradient NMR for assessing reaction efficiency in a single pellet

Science.gov (United States)

Buljubasich, L.; Blümich, B.; Stapf, S.

2011-09-01

An important aspect in assessing the performance of a catalytically active reactor is the accessibility of the reactive sites inside the individual pellets, and the mass transfer of reactants and products to and from these sites. Optimal design often requires a suitable combination of micro- and macropores in order to facilitate mass transport inside the pellet. In an exothermic reaction, fluid exchange between the pellet and the surrounding medium is enhanced by convection, and often by the occurrence of gas bubbles. Determining mass flow in the vicinity of a pellet thus represents a parameter for quantifying the reaction efficiency and its dependence on time or external reaction conditions. Field gradient Nuclear Magnetic Resonance (NMR) methods are suggested as a tool for providing parameters sensitive to this mass flow in a contact-free and non-invasive way. For the example of bubble-forming hydrogen peroxide decomposition in an alumina pellet, the dependence of the mean-squared displacement of fluid molecules on spatial direction, observation time and reaction time is presented, and multi-pulse techniques are employed in order to separate molecular displacements from coherent and incoherent motion on the timescale of the experiment. The reaction progress is followed until the complete decomposition of H 2O 2.

Postinduction minimal residual disease monitoring by polymerase chain reaction in children with acute lymphoblastic leukemia.

Science.gov (United States)

Paganin, Maddalena; Fabbri, Giulia; Conter, Valentino; Barisone, Elena; Polato, Katia; Cazzaniga, Giovanni; Giraldi, Eugenia; Fagioli, Franca; Aricò, Maurizio; Valsecchi, Maria Grazia; Basso, Giuseppe

2014-11-01

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer. Monitoring minimal residual disease (MRD) by using real-time quantitative polymerase chain reaction (RQ-PCR) provides information for patient stratification and individual risk-directed treatment. Cooperative studies have documented that measurement of blast clearance from the bone marrow during and after induction therapy identifies patient populations with different risk of relapse. We explored the possible contribution of measurements of MRD during the course of treatment. We used RQ-PCR to detect MRD in 110 unselected patients treated in Italy in the International Collaborative Treatment Protocol for Children and Adolescents With Acute Lymphoblastic Leukemia (AIEOP-BFM ALL 2000). The trial took place in AIEOP centers during postinduction chemotherapy. Results were categorized as negative, low positive (below the quantitative range [< 5 × 10(-4)]), or high positive (≥ 5 × 10(-4)). Patients with at least one low-positive or high-positive result were assigned to the corresponding subgroup. Patients who tested high positive, low positive, or negative had significantly different cumulative incidences of leukemia relapse: 83.3%, 34.8%, and 8.6%, respectively (P < .001). Two thirds of positive cases were identified within 4 months after induction-consolidation therapy, suggesting that this time frame may be most suitable for cost-effective MRD monitoring, particularly in patients who did not clear their disease at the end of consolidation. These findings provide further insights into the dynamic of MRD and the ongoing effort to define molecular relapse in childhood ALL. © 2014 by American Society of Clinical Oncology.

Monitoring transcranial direct current stimulation induced changes in cortical excitability during the serial reaction time task.

Science.gov (United States)

Ambrus, Géza Gergely; Chaieb, Leila; Stilling, Roman; Rothkegel, Holger; Antal, Andrea; Paulus, Walter

2016-03-11

The measurement of the motor evoked potential (MEP) amplitudes using single pulse transcranial magnetic stimulation (TMS) is a common method to observe changes in motor cortical excitability. The level of cortical excitability has been shown to change during motor learning. Conversely, motor learning can be improved by using anodal transcranial direct current stimulation (tDCS). In the present study, we aimed to monitor cortical excitability changes during an implicit motor learning paradigm, a version of the serial reaction time task (SRTT). Responses from the first dorsal interosseous (FDI) and forearm flexor (FLEX) muscles were recorded before, during and after the performance of the SRTT. Online measurements were combined with anodal, cathodal or sham tDCS for the duration of the SRTT. Negative correlations between the amplitude of online FDI MEPs and SRTT reaction times (RTs) were observed across the learning blocks in the cathodal condition (higher average MEP amplitudes associated with lower RTs) but no significant differences in the anodal and sham conditions. tDCS did not have an impact on SRTT performance, as would be predicted based on previous studies. The offline before-after SRTT MEP amplitudes showed an increase after anodal and a tendency to decrease after cathodal stimulation, but these changes were not significant. The combination of different interventions during tDCS might result in reduced efficacy of the stimulation that in future studies need further attention. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Click chemistry based biomolecular conjugation monitoring using surface-enhanced Raman spectroscopy mapping

DEFF Research Database (Denmark)

Palla, Mirko; Kumar, Shiv; Li, Zengmin

2016-01-01

We describe here a novel surface-enhanced Raman spectroscopy (SERS) based technique for monitoring the conjugation of small molecules by the well-known click reaction between an alkyne and azido moiety on the partner molecules. The monitoring principle is based on the loss of the characteristic...... alkyne/azide Raman signal with triazole formation in the reaction as a function of time. Since these universal Raman reporter groups are specific for click reactions, this method may facilitate a broad range of applications for monitoring the conjugation efficiency of molecules in diverse areas...

HPLC method for rapidly following biodiesel fuel transesterification reaction progress using a core-shell column.

Science.gov (United States)

Allen, Samuel J; Ott, Lisa S

2012-07-01

There are a wide and growing variety of feedstocks for biodiesel fuel. Most commonly, these feedstocks contain triglycerides which are transesterified into the fatty acid alkyl esters (FAAEs) which comprise biodiesel fuel. While the tranesterification reaction itself is simple, monitoring the reaction progress and reaction products is not. Gas chromatography-mass spectrometry is useful for assessing the FAAE products, but does not directly address either the tri-, di-, or monoglycerides present from incomplete transesterification or the free fatty acids which may also be present. Analysis of the biodiesel reaction mixture is complicated by the solubility and physical property differences among the components of the tranesterification reaction mixture. In this contribution, we present a simple, rapid HPLC method which allows for monitoring all of the main components in a biodiesel fuel transesterification reaction, with specific emphasis on the ability to monitor the reaction as a function of time. The utilization of a relatively new, core-shell stationary phase for the HPLC column allows for efficient separation of peaks with short elution times, saving both time and solvent.

MONITORING REACTIONS IN ALKALINE DIRECT ETHANOL FUEL CELLS ASSEMBLED WITH NON-PT-CATALYST

OpenAIRE

Gülzow, Erich; Beyer, Monique; Friedrich, K. Andreas; Pengel, Stefanie; Fischer, Peter; Bettermann, Hans

2011-01-01

This contribution shows how Raman spectroscopy can be used to pursue chemical reactions within fuel cells. For this, the oxidation of ethanol occurring in an alkaline direct ethanolic fuel cell was investigated. The analysis of a sequence of Raman spectra recorded during the reaction shows that ethanol was solely oxidized to acetate in a unique reaction.

Real Time Monitoring of Containerless Microreactions in Acoustically Levitated Droplets via Ambient Ionization Mass Spectrometry.

Science.gov (United States)

Crawford, Elizabeth A; Esen, Cemal; Volmer, Dietrich A

2016-09-06

Direct in-droplet (in stillo) microreaction monitoring using acoustically levitated micro droplets has been achieved by combining acoustic (ultrasonic) levitation for the first time with real time ambient tandem mass spectrometry (MS/MS). The acoustic levitation and inherent mixing of microliter volumes of reactants (3 μL droplets), yielding total reaction volumes of 6 μL, supported monitoring the acid-catalyzed degradation reaction of erythromycin A. This reaction was chosen to demonstrate the proof-of-principle of directly monitoring in stillo microreactions via hyphenated acoustic levitation and ambient ionization mass spectrometry. The microreactions took place completely in stillo over 30, 60, and 120 s within the containerless stable central pressure node of an acoustic levitator, thus readily promoting reaction miniaturization. For the evaluation of the miniaturized in stillo reactions, the degradation reactions were also carried out in vials (in vitro) with a total reaction volume of 400 μL. The reacted in vitro mixtures (6 μL total) were similarly introduced into the acoustic levitator prior to ambient ionization MS/MS analysis. The in stillo miniaturized reactions provided immediate real-time snap-shots of the degradation process for more accurate reaction monitoring and used a fraction of the reactants, while the larger scale in vitro reactions only yielded general reaction information.

The Dutch Brucella abortus monitoring programme for cattle: the impact of false-positive serological reactions and comparison of serological tests.

Science.gov (United States)

Emmerzaal, A; de Wit, J J; Dijkstra, Th; Bakker, D; van Zijderveld, F G

2002-02-01

The Dutch national Brucella abortus eradication programme for cattle started in 1959. Sporadic cases occurred yearly until 1995; the last infected herd was culled in 1996. In August 1999 the Netherlands was declared officially free of bovine brucellosis by the European Union. Before 1999, the programme to monitor the official Brucella-free status of bovine herds was primarily based on periodical testing of dairy herds with the milk ring test (MRT) and serological testing of all animals older than 1 year of age from non-dairy herds, using the micro-agglutination test (MAT) as screening test. In addition, serum samples of cattle that aborted were tested with the MAT. The high number of false positive reactions in both tests and the serum agglutination test (SAT) and complement fixation test (CFT) used for confirmation seemed to result in unnecessary blockade of herds, subsequent testing and slaughter of animals. For this reason, a validation study was performed in which three indirect enzyme-linked immunosorbent assays (ELISAs), the CFT and the SAT were compared using a panel of sera from brucellosis-free cattle, sera from experimentally infected cattle, and sera from cattle experimentally infected with bacteria which are known to induce cross-reactive antibodies (Pasteurella, Salmonella, Yersinia, and Escherichia). Moreover, four ELISAs and the MRT were compared using a panel of 1000 bulk milk samples from Brucella-free herds and 12 milk samples from Brucella abortus- infected cattle. It is concluded that the ELISA obtained from ID-Lelystad is the most suitable test to monitor the brucelosis free status of herds because it gives rise to fewer false-positive reactions than the SAT.

Action monitoring and perfectionism in anorexia nervosa

NARCIS (Netherlands)

Pieters, G.L.M.; Bruijn, E.R.A. de; Maas, Y.J.; Hulstijn, W.; Vandereycken, W.; Peuskens, J.; Sabbe, B.G.C.

2007-01-01

To study action monitoring in anorexia nervosa, behavioral and EEG measures were obtained in underweight anorexia nervosa patients (n = 17) and matched healthy controls (n = 19) while performing a speeded choice-reaction task. Our main measures of interest were questionnaire outcomes, reaction

Analysis of elements present in beers and brewing waters by neutron activation analysis

International Nuclear Information System (INIS)

Krausova, Ivana; Kucera, Jan; Dostalek, Pavel; Potesil, Vaclav

2011-01-01

Neutron activation analysis (NAA) was used for determination of Si, Na, K, Ca, Sc, V, Cr, Mn, Fe, Co, Zn, Rb, Cs, and La in Czech beers and brewing waters. The Si concentration in beer determined by the reaction 29 Si(n,p) 29 Al with fast neutrons confirmed that beer is an important Si source in human diet. Determination of other trace elements by NAA with the whole spectrum of reactor neutrons aimed at the feasibility of identification of Gambrinus beers brewed in various breweries. The elements Ca and V appeared to be the best candidates for this purpose. The concentrations of elements determined by NAA were also compared with the recommended daily element intake for humans. The accuracy of the method was proved by analysis of reference materials, specifically NIST SRM 2704 Buffalo River Sediment, NIST SRM 1633b Coal Fly Ash, and NIST SRM 1515 Apple Leaves. (author)

Combustion kinetics and reaction pathways

Energy Technology Data Exchange (ETDEWEB)

Klemm, R.B.; Sutherland, J.W. [Brookhaven National Laboratory, Upton, NY (United States)

1993-12-01

This project is focused on the fundamental chemistry of combustion. The overall objectives are to determine rate constants for elementary reactions and to elucidate the pathways of multichannel reactions. A multitechnique approach that features three independent experiments provides unique capabilities in performing reliable kinetic measurements over an exceptionally wide range in temperature, 300 to 2500 K. Recent kinetic work has focused on experimental studies and theoretical calculations of the methane dissociation system (CH{sub 4} + Ar {yields} CH{sub 3} + H + Ar and H + CH{sub 4} {yields} CH{sub 3} + H{sub 2}). Additionally, a discharge flow-photoionization mass spectrometer (DF-PIMS) experiment is used to determine branching fractions for multichannel reactions and to measure ionization thresholds of free radicals. Thus, these photoionization experiments generate data that are relevant to both reaction pathways studies (reaction dynamics) and fundamental thermochemical research. Two distinct advantages of performing PIMS with high intensity, tunable vacuum ultraviolet light at the National Synchrotron Light Source are high detection sensitivity and exceptional selectivity in monitoring radical species.

Theoretical calculation of n + {sup 59}Co reaction in energy region up to 100 MeV

Energy Technology Data Exchange (ETDEWEB)

Qingbiao, Shen; Baosheng, Yu; Dunjiu, Cai [Chinese Nuclear Data Center, Beijing, BJ (China)

1996-06-01

A set of neutron optical potential parameters for {sup 59}Co in energy region of 2{approx}100 MeV was obtained based on concerned experimental data. Various cross sections of n + {sup 59}Co reactions were calculated and predicted. The calculated results show that the activation products {sup 58,57}Co, {sup 59}Fe and {sup 56}Mn are main neutron monitor reaction products for n + {sup 59}Co reaction in energy range up to 100 MeV. {sup 54}Mn production reaction can be a promising neutron monitor reaction in the energy region from 30 to 100 MeV. (6 figs.).

Quantitative changes in proteins responsible for flavonoid and anthocyanin biosynthesis in strawberry fruit at different ripening stages: A targeted quantitative proteomic investigation employing multiple reaction monitoring.

Science.gov (United States)

Song, Jun; Du, Lina; Li, Li; Kalt, Wilhelmina; Palmer, Leslie Campbell; Fillmore, Sherry; Zhang, Ying; Zhang, ZhaoQi; Li, XiHong

2015-06-03

To better understand the regulation of flavonoid and anthocyanin biosynthesis, a targeted quantitative proteomic investigation employing LC-MS with multiple reaction monitoring was conducted on two strawberry cultivars at three ripening stages. This quantitative proteomic workflow was improved through an OFFGEL electrophoresis to fractionate peptides from total protein digests. A total of 154 peptide transitions from 47 peptides covering 21 proteins and isoforms related to anthocyanin biosynthesis were investigated. The normalized protein abundance, which was measured using isotopically-labeled standards, was significantly changed concurrently with increased anthocyanin content and advanced fruit maturity. The protein abundance of phenylalanine ammonia-lyase; anthocyanidin synthase, chalcone isomerase; flavanone 3-hydroxylase; dihydroflavonol 4-reductase, UDP-glucose:flavonoid-3-O-glucosyltransferase, cytochrome c and cytochrome C oxidase subunit 2, was all significantly increased in fruit of more advanced ripeness. An interaction between cultivar and maturity was also shown with respect to chalcone isomerase. The good correlation between protein abundance and anthocyanin content suggested that a metabolic control point may exist for anthocyanin biosynthesis. This research provides insights into the process of anthocyanin formation in strawberry fruit at the level of protein concentration and reveals possible candidates in the regulation of anthocyanin formation during fruit ripening. To gain insight into the molecular mechanisms contributing to flavonoids and anthocyanin biosynthesis and regulation of strawberry fruit during ripening is challenging due to limited molecular biology tools and established hypothesis. Our targeted proteomic approach employing LC-MS/MS analysis and MRM technique to quantify proteins in relation to flavonoids and anthocyanin biosynthesis and regulation in strawberry fruit during fruit ripening is novel. The identification of peptides

Novel Profluorescent Nitroxides for Monitoring Alkyl Radical Reactions During Radiation Degradation

International Nuclear Information System (INIS)

George, G.

2006-01-01

Hindered amine stabilizers (HAS) are effective at retarding the photo-oxidative and high energy radiation degradation of PP and in certain circumstances, also thermo-oxidative degradation. The effectiveness of HAS as retarders of oxidation relies on the oxidation of the N-C bond by polymer hydroperoxide, ROOH, to form the nitroxyl group -NO which is the scavenger of polymer alkyl radicals, R. This reaction, which produces the alkoxy amine: -NO-R, must be competitive with the reaction of R with oxygen (which gives the chain-carrying peroxy radical, RO 2 ) if this stabilization mechanism is to be important in the inhibition of radiation-induced oxidative degradation of polyolefins by HAS. The rate of this reaction is high and in solution the rate coefficient is from 1 to 9x10 8 l mol - 1 s - 1. The efficient radical trapping by nitroxides has been widely employed in spin-trapping studies by electron spin resonance (esr) spectroscopy]. In addition to the hindered piperidine structure of commercial HAS, more rigid aromatic systems have been studied that are more stable to oxidative degradation and are more efficient at scavenging alkyl radicals. One such family is the iso-indoline nitroxide system, TMDBIO, shown below which, as it contains the phenanthrene fluorophore, is termed phenanthrene nitroxide. This nitroxide only becomes fluorescent when it reacts with alkyl radicals or is reduced and is termed profluorescent. TMDBIO has a vanishingly small fluorescence quantum yield (φ∼10 - 4) due to the enhanced intersystem crossing from the first excited singlet state to the ground state due to electron exchange interactions of the nitroxyl radical. When the nitroxide traps an alkyl radical, R, the resulting alkoxy amine is fluorescent (φ∼10 - 1) and the emission intensity is a measure of the number of reactions that have occurred. This property may be exploited by using quantitative fluorescence spectroscopy to follow the reaction of the nitroxide with alkyl radicals

Evaluation of cross sections for neutron monitor reactions {sup 90}Zr(n,x){sup 89,88}Zr, {sup 88,87,86}Y from threshold to 100 MeV

Energy Technology Data Exchange (ETDEWEB)

Baosheng, Yu; Qingbiao, Shen; Dunjiu, Cai [Chinese Nuclear Data Center, Beijing, BJ (China)

1996-06-01

The cross sections for {sup 90}Zr(n,x){sup 89,88}Zr and {sup 90}Zr(n,x){sup 88,87,86}Y reactions in intermediate energy region are useful in neutron field monitor, safety and material damage research. Below 20 MeV, the evaluated cross sections for {sup 90}Zr(n,2n){sup 89}Zr reaction are recommended based on the recent experimental data, including the new measured results in CIAE (Above 20 MeV). The measured cross sections are still insufficient to do evaluation. So the evaluation for {sup 90}Zr(n,x){sup 89,88}Zr and {sup 90}Zr(n,x){sup 88,87,86}Y reactions from threshold to 100 MeV are based on experimental and calculated data. (2 figs.).

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Energy Technology Data Exchange (ETDEWEB)

Huang, Shih-Yi [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Jiang, Shiuh-Jen, E-mail: sjjiang@faculty.nsysu.edu.tw [Department of Chemistry, National Sun Yat-sen University, Kaohsiung 80424, Taiwan (China); Department of Medical Laboratory Science and Biotechnology, Kaohsiung Medical University, Kaohsiung 80708, Taiwan (China); Sahayam, A.C. [National Centre for Compositional Characterisation of Materials (CCCM), Hyderabad (India)

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min{sup −1} methane (CH{sub 4}) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g{sup −1} for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g{sup −1} (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

International Nuclear Information System (INIS)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A.C.

2014-01-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min −1 methane (CH 4 ) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g −1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g −1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions. - Highlights: • Determination of Cr, Fe, Cu, Zn and Se in cereal samples • Ultrasonic slurry sampling in combination with DRC-ICP-MS • Better sensitivity with thioacetamide modifier in ETV • Decreased sample preparation time with solid sampling • Validation with NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour

Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

Science.gov (United States)

Latino, Diogo A R S; Aires-de-Sousa, João

2014-01-01

The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1)H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants) and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1)H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps) produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF), the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure elucidation of

Automatic NMR-based identification of chemical reaction types in mixtures of co-occurring reactions.

Directory of Open Access Journals (Sweden)

Diogo A R S Latino

Full Text Available The combination of chemoinformatics approaches with NMR techniques and the increasing availability of data allow the resolution of problems far beyond the original application of NMR in structure elucidation/verification. The diversity of applications can range from process monitoring, metabolic profiling, authentication of products, to quality control. An application related to the automatic analysis of complex mixtures concerns mixtures of chemical reactions. We encoded mixtures of chemical reactions with the difference between the (1H NMR spectra of the products and the reactants. All the signals arising from all the reactants of the co-occurring reactions were taken together (a simulated spectrum of the mixture of reactants and the same was done for products. The difference spectrum is taken as the representation of the mixture of chemical reactions. A data set of 181 chemical reactions was used, each reaction manually assigned to one of 6 types. From this dataset, we simulated mixtures where two reactions of different types would occur simultaneously. Automatic learning methods were trained to classify the reactions occurring in a mixture from the (1H NMR-based descriptor of the mixture. Unsupervised learning methods (self-organizing maps produced a reasonable clustering of the mixtures by reaction type, and allowed the correct classification of 80% and 63% of the mixtures in two independent test sets of different similarity to the training set. With random forests (RF, the percentage of correct classifications was increased to 99% and 80% for the same test sets. The RF probability associated to the predictions yielded a robust indication of their reliability. This study demonstrates the possibility of applying machine learning methods to automatically identify types of co-occurring chemical reactions from NMR data. Using no explicit structural information about the reactions participants, reaction elucidation is performed without structure

Monitoring benzene formation from benzoate in model systems by proton transfer reaction-mass spectrometry

Science.gov (United States)

Aprea, Eugenio; Biasioli, Franco; Carlin, Silvia; Märk, Tilmann D.; Gasperi, Flavia

2008-08-01

The presence of benzene in food and in particular in soft drinks has been reported in several studies and should be considered in fundamental investigations about formation of this carcinogen compound as well as in quality control. Proton transfer reaction-mass spectrometry (PTR-MS) has been used here for rapid, direct quantification of benzene and to monitor its formation in model systems related to the use of benzoate, a common preservative, in presence of ascorbic acid: a widespread situation that yields benzene in, e.g., soft drinks and fruit juices. Firstly, we demonstrate here that PTR-MS allows a rapid determination of benzene that is in quantitative agreement with independent solid phase micro-extraction/gas chromatography (SPME/GC) analysis. Secondly, as a case study, the effect of different sugars (sucrose, fructose and glucose) on benzene formation is investigated indicating that they inhibit its formation and that this effect is enhanced for reducing sugars. The sugar-induced inhibition of benzene formation depends on several parameters (type and concentration of sugar, temperature, time) but can be more than 80% in situations that can be expected in the storage of commercial soft drinks. This is consistent with the reported observations of higher benzene concentrations in sugar-free soft drinks.

The importance of monitoring adverse drug reactions in pediatric patients: the results of a national surveillance program in Italy.

Science.gov (United States)

Carnovale, Carla; Brusadelli, Tatiana; Zuccotti, GianVincenzo; Beretta, Silvia; Sullo, Maria Giuseppa; Capuano, Annalisa; Rossi, Francesco; Moschini, Martina; Mugelli, Alessandro; Vannacci, Alfredo; Laterza, Marcella; Clementi, Emilio; Radice, Sonia

2014-09-01

To gain information on safety of drugs used in pediatrics through a 4-year post-marketing active pharmacovigilance program. The program sampled the Italian population and was termed 'Monitoring of the Adverse Effects in Pediatric population' (MEAP). Adverse drug reactions (ADRs) were collected for individuals aged 0 - 17 years treated in hospitals and territorial health services in Lombardy, Tuscany, Apulia and Campania; located to gain an appropriate sampling of the population. ADRs were evaluated using the Adverse Drug Reaction Probability Scale (Naranjo) and analyzed with respect to time, age, sex, category of ADR, seriousness, suspected medicines, type of reporter and off-label use. We collected and analyzed reports from 3539 ADRs. Vaccines, antineoplastic and psychotropic drugs were the most frequently pharmacotherapeutic subgroups involved. Seventeen percent of reported ADRs were serious; of them fever, vomiting and angioedema were the most frequently reported. Eight percent of ADRs were associated with off-label use, and 10% were unknown ADRs. Analysis of these revealed possible strategies of therapy optimization. The MEAP project demonstrated that active post-marketing pharmacovigilance programs are a valid strategy to increase awareness on pediatric pharmacology, reduce underreporting and provide information on drug actions in pediatrics. This information enhances drug therapy optimization in the pediatric patients.

Utilization of the intense pulsed neutron source (IPNS) at Argonne National Laboratory for neutron activation analysis

International Nuclear Information System (INIS)

Heinrich, R.R.; Greenwood, L.R.; Popek, R.J.; Schulke, A.W. Jr.

1983-01-01

The Intense Pulsed Neutron Source (IPNS) neutron scattering facility (NSF) has been investigated for its applicability to neutron activation analysis. A polyethylene insert has been added to the vertical hole VT3 which enhances the thermal neutron flux by a factor of two. The neutron spectral distribution at this position has been measured by the multiple-foil technique which utilized 28 activation reactions and the STAYSL computer code. The validity of this spectral measurement was tested by two irradiations of National Bureau of Standards SRM-1571 (orchard leaves), SRM-1575 (pine needles), and SRM-1645 (river sediment). The average thermal neutron flux for these irradiations normalized to 10 μamp proton beam is 4.0 x 10 11 n/cm 2 -s. Concentrations of nine trace elements in each of these SRMs have been determined by gamma-ray spectrometry. Agreement of measured values to certified values is demonstrated to be within experiment error

Substoichiometric extraction of chromium

International Nuclear Information System (INIS)

Shigematsu, T.; Kudo, K.

1980-01-01

Substoichiometric extraction of chromium with tetraphenylarsonium chloride (TPACl), tri-n-octylamine (TNOA), diethylammonium diethyldithiocarbamate (DDDC) and ammonium pyrrolidinedithiocarbamate (APDC) was examined in detail. Chromium can be extracted substoichiometrically in a pH range, which is 1.1-2.6 for the TPACl compound, 0.6-2.3 for the TNOA compound, 5.1-6.4 for the DDDC chelate and 3.9-4.9 for the APDC chelate. Chromium in high-purity calcium carbonate, Orchard Leaves (NBS SRM-1571) and Brewers Yeast (NBS SRM-1569) was determined by neutron activation analysis combined with substoichiometric extraction by DDDC and APDC. The values of 2.0+-0.02 ppm and 2.6+-0.2 ppm were obtained for Brewers Yeast and Orchard Leaves, respectively. These values were in good agreement with those reported by NBS. The reaction mechanism and the reaction ratio between hexavalent chromium and dithiocarbamate are also discussed. (author)

Automatic identification approach for high-performance liquid chromatography-multiple reaction monitoring fatty acid global profiling.

Science.gov (United States)

Tie, Cai; Hu, Ting; Jia, Zhi-Xin; Zhang, Jin-Lan

2015-08-18

Fatty acids (FAs) are a group of lipid molecules that are essential to organisms. As potential biomarkers for different diseases, FAs have attracted increasing attention from both biological researchers and the pharmaceutical industry. A sensitive and accurate method for globally profiling and identifying FAs is required for biomarker discovery. The high selectivity and sensitivity of high-performance liquid chromatography-multiple reaction monitoring (HPLC-MRM) gives it great potential to fulfill the need to identify FAs from complicated matrices. This paper developed a new approach for global FA profiling and identification for HPLC-MRM FA data mining. Mathematical models for identifying FAs were simulated using the isotope-induced retention time (RT) shift (IRS) and peak area ratios between parallel isotope peaks for a series of FA standards. The FA structures were predicated using another model based on the RT and molecular weight. Fully automated FA identification software was coded using the Qt platform based on these mathematical models. Different samples were used to verify the software. A high identification efficiency (greater than 75%) was observed when 96 FA species were identified in plasma. This FAs identification strategy promises to accelerate FA research and applications.

Catalytic activation of molecular hydrogen in alkyne hydrogenation reactions by lanthanide metal vapor reaction products

International Nuclear Information System (INIS)

Evans, W.J.; Bloom, I.; Engerer, S.C.

1983-01-01

A rotary metal vapor was used in the synthesis of Lu, Er, Nd, Sm, Yb, and La alkyne, diene, and phosphine complexes. A typical catalytic hydrogenation experiment is described. The lanthanide metal vapor product is dissolved in tetrahydrofuran or toluene and placed in a pressure reaction vessel 3-hexyne (or another substrate) is added, the chamber attached to a high vacuum line, cooled to -196 0 C, evacuated, warmed to ambient temperature and hydrogen is added. The solution is stirred magnetically while the pressure in monitored. The reaction products were analyzed by gas chromatography. Rates and products of various systems are listed. This preliminary survey indicates that catalytic reaction chemistry is available to these metals in a wide range of coordination environments. Attempts to characterize these compounds are hampered by their paramagnetic nature and their tendency to polymerize

Photocatalytic degradation of paracetamol: intermediates and total reaction mechanism.

Science.gov (United States)

Moctezuma, Edgar; Leyva, Elisa; Aguilar, Claudia A; Luna, Raúl A; Montalvo, Carlos

2012-12-01

The advanced oxidation of paracetamol (PAM) promoted by TiO(2)/UV system in aqueous medium was investigated. Monitoring this reaction by HPLC and TOC, it was demonstrated that while oxidation of paracetamol is quite efficient under these conditions, its mineralization is not complete. HPLC indicated the formation of hydroquinone, benzoquinone, p-aminophenol and p-nitrophenol in the reaction mixtures. Further evidence of p-nitrophenol formation was obtained following the reaction by UV-vis spectroscopy. Continuous monitoring by IR spectroscopy demonstrated the breaking of the aromatic amide present in PAM and subsequent formation of several aromatic intermediate compounds such as p-aminophenol and p-nitrophenol. These aromatic compounds were eventually converted into trans-unsaturated carboxylic acids. Based on these experimental results, an alternative deacylation mechanism for the photocatalytic oxidation of paracetamol is proposed. Our studies also demonstrated IR spectroscopy to be a useful technique to investigate oxidative mechanisms of pharmaceutical compounds. Copyright © 2012 Elsevier B.V. All rights reserved.

Incore monitoring device

International Nuclear Information System (INIS)

Tai, Ichiro; Shirayama, Shin-pei; Nozaki, Shin-ichi.

1978-01-01

Purpose: To provide an incore monitoring device wherein both radiation monitoring and acoustic monitoring are carried out simultaneously by one detector, whereby installation of the device and signal pick-up are facilitated. Incore conditions are accurately grasped. Constitution: When a neutron is irradiated in a state where a DC voltage is applied between the electrode and the vessel in the device, an ionization current is occured by (n.γ) reaction of the transformed substance as in an ionization chamber, Accordingly, a voltage drop occurs at both ends of the resistor of the radiation signal processing system, as a result of which a neutron flux can be detected. Further, when a sound is generated in the reactor, the monitoring device bottom wall which formed by a piezoelectric element detects the sound-waves. This output signal is picked up by the acoustic signal processing system to judge the generation of sound. (Aizawa, K.)

Moisture monitoring and control system engineering study

International Nuclear Information System (INIS)

Carpenter, K.E.; Fadeff, J.G.

1995-01-01

During the past 50 years, a wide variety of chemical compounds have been placed in the 149 single-shell tanks (SSTS) on the Hanford Site. A concern relating to chemical stability, chemical control, and safe storage of the waste is the potential for propagating reactions as a result of ferrocyanide-oxidizer and organic-oxidizer concentrations in the SSTS. Propagating reactions in fuel-nitrate mixtures are precluded if the amounts of fuel and moisture present in the waste are within specified limits. Because most credible ignition sources occur near the waste surface, the main emphasis of this study is toward monitoring and controlling moisture in the top 14 cm (5.5 in.) of waste. The purpose of this engineering study is to recommend a moisture monitoring and control system for use in SSTs containing sludge and saltcake. This study includes recommendations for: (1) monitoring and controlling moisture in SSTs; (2) the fundamental design criteria for a moisture monitoring and control system; and (3) criteria for the deployment of a moisture monitoring and control system in hanford Site SSTs. To support system recommendations, technical bases for selecting and using a moisture monitoring and control system are presented. Key functional requirements and a conceptual design are included to enhance system development and establish design criteria

Correlative Super-Resolution Microscopy: New Dimensions and New Opportunities.

Science.gov (United States)

Hauser, Meghan; Wojcik, Michal; Kim, Doory; Mahmoudi, Morteza; Li, Wan; Xu, Ke

2017-06-14

Correlative microscopy, the integration of two or more microscopy techniques performed on the same sample, produces results that emphasize the strengths of each technique while offsetting their individual weaknesses. Light microscopy has historically been a central method in correlative microscopy due to its widespread availability, compatibility with hydrated and live biological samples, and excellent molecular specificity through fluorescence labeling. However, conventional light microscopy can only achieve a resolution of ∼300 nm, undercutting its advantages in correlations with higher-resolution methods. The rise of super-resolution microscopy (SRM) over the past decade has drastically improved the resolution of light microscopy to ∼10 nm, thus creating exciting new opportunities and challenges for correlative microscopy. Here we review how these challenges are addressed to effectively correlate SRM with other microscopy techniques, including light microscopy, electron microscopy, cryomicroscopy, atomic force microscopy, and various forms of spectroscopy. Though we emphasize biological studies, we also discuss the application of correlative SRM to materials characterization and single-molecule reactions. Finally, we point out current limitations and discuss possible future improvements and advances. We thus demonstrate how a correlative approach adds new dimensions of information and provides new opportunities in the fast-growing field of SRM.

Skyline: an open source document editor for creating and analyzing targeted proteomics experiments.

Science.gov (United States)

MacLean, Brendan; Tomazela, Daniela M; Shulman, Nicholas; Chambers, Matthew; Finney, Gregory L; Frewen, Barbara; Kern, Randall; Tabb, David L; Liebler, Daniel C; MacCoss, Michael J

2010-04-01

Skyline is a Windows client application for targeted proteomics method creation and quantitative data analysis. It is open source and freely available for academic and commercial use. The Skyline user interface simplifies the development of mass spectrometer methods and the analysis of data from targeted proteomics experiments performed using selected reaction monitoring (SRM). Skyline supports using and creating MS/MS spectral libraries from a wide variety of sources to choose SRM filters and verify results based on previously observed ion trap data. Skyline exports transition lists to and imports the native output files from Agilent, Applied Biosystems, Thermo Fisher Scientific and Waters triple quadrupole instruments, seamlessly connecting mass spectrometer output back to the experimental design document. The fast and compact Skyline file format is easily shared, even for experiments requiring many sample injections. A rich array of graphs displays results and provides powerful tools for inspecting data integrity as data are acquired, helping instrument operators to identify problems early. The Skyline dynamic report designer exports tabular data from the Skyline document model for in-depth analysis with common statistical tools. Single-click, self-updating web installation is available at http://proteome.gs.washington.edu/software/skyline. This web site also provides access to instructional videos, a support board, an issues list and a link to the source code project.

Chloroquine Interference with Hemoglobin Endocytic Trafficking Suppresses Adaptive Heme and Iron Homeostasis in Macrophages: The Paradox of an Antimalarial Agent

Directory of Open Access Journals (Sweden)

Christian A. Schaer

2013-01-01

Full Text Available The CD163 scavenger receptor pathway for Hb:Hp complexes is an essential mechanism of protection against the toxicity of extracellular hemoglobin (Hb, which can accumulate in the vasculature and within tissues during hemolysis. Chloroquine is a lysosomotropic agent, which has been extensively used as an antimalarial drug in the past, before parasite resistance started to limit its efficacy in most parts of the world. More recent use of chloroquine is related to its immunomodulatory activity in patients with autoimmune diseases, which may also involve hemolytic disease components. In this study we examined the effects of chloroquine on the human Hb clearance pathway. For this purpose we developed a new mass-spectrometry-based method to specifically quantify intracellular Hb peptides within the endosomal-lysosomal compartment by single reaction monitoring (SRM. We found that chloroquine exposure impairs trafficking of Hb:Hp complexes through the endosomal-lysosomal compartment after internalization by CD163. Relative quantification of intracellular Hb peptides by SRM confirmed that chloroquine blocked cellular Hb:Hp catabolism. This effect suppressed the cellular heme-oxygenase-1 (HO-1 response and shifted macrophage iron homeostasis towards inappropriately high expression of the transferrin receptor with concurrent inhibition of ferroportin expression. A functional deficiency of Hb detoxification and heme-iron recycling may therefore be an adverse consequence of chloroquine treatment during hemolysis.

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

Directory of Open Access Journals (Sweden)

L. Xia

2017-10-01

Full Text Available A range of solar radiation management (SRM techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air

Impacts of stratospheric sulfate geoengineering on tropospheric ozone

Science.gov (United States)

Xia, Lili; Nowack, Peer J.; Tilmes, Simone; Robock, Alan

2017-10-01

A range of solar radiation management (SRM) techniques has been proposed to counter anthropogenic climate change. Here, we examine the potential effects of stratospheric sulfate aerosols and solar insolation reduction on tropospheric ozone and ozone at Earth's surface. Ozone is a key air pollutant, which can produce respiratory diseases and crop damage. Using a version of the Community Earth System Model from the National Center for Atmospheric Research that includes comprehensive tropospheric and stratospheric chemistry, we model both stratospheric sulfur injection and solar irradiance reduction schemes, with the aim of achieving equal levels of surface cooling relative to the Representative Concentration Pathway 6.0 scenario. This allows us to compare the impacts of sulfate aerosols and solar dimming on atmospheric ozone concentrations. Despite nearly identical global mean surface temperatures for the two SRM approaches, solar insolation reduction increases global average surface ozone concentrations, while sulfate injection decreases it. A fundamental difference between the two geoengineering schemes is the importance of heterogeneous reactions in the photochemical ozone balance with larger stratospheric sulfate abundance, resulting in increased ozone depletion in mid- and high latitudes. This reduces the net transport of stratospheric ozone into the troposphere and thus is a key driver of the overall decrease in surface ozone. At the same time, the change in stratospheric ozone alters the tropospheric photochemical environment due to enhanced ultraviolet radiation. A shared factor among both SRM scenarios is decreased chemical ozone loss due to reduced tropospheric humidity. Under insolation reduction, this is the dominant factor giving rise to the global surface ozone increase. Regionally, both surface ozone increases and decreases are found for both scenarios; that is, SRM would affect regions of the world differently in terms of air pollution. In conclusion

Study of the performance of three LC-MS/MS platforms for analysis of perfluorinated compounds

Energy Technology Data Exchange (ETDEWEB)

Llorca, Marta; Farre, Marinella [IDAEA-CSIC, Department of Environmental Chemistry, Barcelona (Spain); Pico, Yolanda [Universitat de Valencia, Laboratori de Nutricio i Bromatologia, Facultat de Farmacia, Burjassot, Valencia (Spain); Barcelo, Damia [IDAEA-CSIC, Department of Environmental Chemistry, Barcelona (Spain); King Saud University, Riyadh (Saudi Arabia)

2010-10-15

The analytical suitabilities of three different liquid chromatography-tandem mass spectrometry (LC-MS/MS) systems, (1) triple quadrupole (QqQ), (2) conventional 3D ion trap (IT), and (3) quadrupole-linear IT (QqLIT), to determine trace levels of perfluorinated compounds (PFCs) in fish and shellfish were compared. Sample preparation was performed using alkaline extraction and solid-phase-extraction cleanup. This evaluation was focused on both quantitative (sensitivity, precision, and accuracy) and qualitative (identification capabilities) aspects. In the three instruments, the former facet was evaluated using selected reaction monitoring (SRM), which is the standard mode for quantitative LC-MS/MS analysis. Accuracy was similar in the three systems, with recoveries always over 70 %. Precision was better for the QqLIT and QqQ systems (7-15%) than for the IT system (10-17%). The QqLIT (working in SRM mode) and QqQ systems offered a linear dynamic range of at least 3 orders of magnitude, whereas that of the IT system was 2 orders of magnitude. The QqLIT system achieved at least 20-fold higher sensitivity than the QqQ system, and this was at least tenfold higher sensitivity than for the IT system. In the IT system, identification was based on sensitive full mass range acquisition and MS{sup n} fragmentation and in the QqLIT system, it was based on the use of an information-dependent-acquisition scan function, which allows the combination of an SRM or MS full scan acting as the survey scan and an enhanced product ion scan followed by MS{sup 3} as the dependent scan in the same analysis. Three instruments were applied to monitor the content in fish and shellfish (anchovies, swordfish, tuna, mussels, and oysters) obtained from Valencia and Barcelona markets (Spain). The eight target PFCs were detected at mean concentrations in the range from 10 ng kg {sup -1} (perfluoro-7-methyloctanoic acid and perfluoro-1-decanesulfonate) to 4,200 ng kg {sup -1} (perfluoropentanoic acid

Molecular beam studies of reaction dynamics

International Nuclear Information System (INIS)

Lee, Yuan T.

1991-03-01

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation

Molecular beam studies of reaction dynamics

Energy Technology Data Exchange (ETDEWEB)

Lee, Y.T. [Lawrence Berkeley Laboratory, CA (United States)

1993-12-01

The major thrust of this research project is to elucidate detailed dynamics of simple elementary reactions that are theoretically important and to unravel the mechanism of complex chemical reactions or photochemical processes that play important roles in many macroscopic processes. Molecular beams of reactants are used to study individual reactive encounters between molecules or to monitor photodissociation events in a collision-free environment. Most of the information is derived from measurement of the product fragment energy, angular, and state distributions. Recent activities are centered on the mechanisms of elementary chemical reactions involving oxygen atoms with unsaturated hydrocarbons, the dynamics of endothermic substitution reactions, the dependence of the chemical reactivity of electronically excited atoms on the alignment of excited orbitals, the primary photochemical processes of polyatomic molecules, intramolecular energy transfer of chemically activated and locally excited molecules, the energetics of free radicals that are important to combustion processes, the infrared-absorption spectra of carbonium ions and hydrated hydronium ions, and bond-selective photodissociation through electric excitation.

Standard Test Method for Measuring Fast-Neutron Reaction Rates by Radioactivation of Niobium

CERN Document Server

American Society for Testing and Materials. Philadelphia

2008-01-01

1.1 This test method describes procedures for measuring reaction rates by the activation reaction 93Nb(n,n′)93mNb. 1.2 This activation reaction is useful for monitoring neutrons with energies above approximately 0.5 MeV and for irradiation times up to about 30 years. 1.3 With suitable techniques, fast-neutron reaction rates for neutrons with energy distribution similar to fission neutrons can be determined in fast-neutron fluences above about 1016cm−2. In the presence of high thermal-neutron fluence rates (>1012cm−2·s−1), the transmutation of 93mNb due to neutron capture should be investigated. In the presence of high-energy neutron spectra such as are associated with fusion and spallation sources, the transmutation of 93mNb by reactions such as (n,2n) may occur and should be investigated. 1.4 Procedures for other fast-neutron monitors are referenced in Practice E 261. 1.5 Fast-neutron fluence rates can be determined from the reaction rates provided that the appropriate cross section information ...

Coherent synthesis with dedicated instrumentation for MW-assisted chemistry (T3)

International Nuclear Information System (INIS)

Keil, E.M.

2002-01-01

Full text: Microwave (MW) assisted organic chemistry is a still new and exciting field in organic synthesis. The streamlining power of this type of methodology is typically characterized by an increase in yield and a decrease in reaction times. Within quite a short time all major companies which need to synthesize new compounds efficiently and successfully has realized these advantages and have invested in this technology. The instruments presented here are specifically designed for organic synthesis. They incorporate single mode resonator (SRM) and dynamic field tuning designs. This latest developments in modern microwave technology is used due to the high demand for reproducible control and the wide variety of reaction types used in organic synthesis. In coherent synthesis, microwave assisted organic reactions can be performed under extreme temperature and pressure conditions. It is therefore essential to have sensitive control and advanced, adjustable energy-steering systems. The dynamic field tuning system is based upon proprietary technology involving improved software and hardware. The system is capable of detecting the absorbance characteristics of the reaction mixture and optimizes the coupling and quantity of energy delivered. It provides optimal efficiency and even temperature distribution in the reaction mixture regardless of involved materials, as e.g. a wide range of solvents or reagents. Built-in temperature and pressure sensors allow real time monitoring and control of each individual reaction. The work flow manager software is a platform from where to plan and perform experiments, monitor reactions and document all results. The chemical reactions are performed in uniquely designed process vials which allow even energy distribution throughout the entire reaction volume. The vials are manufactured from microwave-immune materials that are free from contaminants. The closure design is optimized for a complete seal allowing safe working pressures up to

Structure of fungal oxyluciferin, the product of the bioluminescence reaction.

Science.gov (United States)

Purtov, K V; Osipova, Z M; Petushkov, V N; Rodionova, N S; Tsarkova, A S; Kotlobay, A A; Chepurnykh, T V; Gorokhovatsky, A Yu; Yampolsky, I V; Gitelson, J I

2017-11-01

The structure of fungal oxyluciferin was determined, the enzymatic bioluminescence reaction under substrate saturation conditions with discrete monitoring of formed products was conducted, and the structures of the end products of the reaction were established. On the basis of these studies, the scheme of oxyluciferin degradation to the end products was developed. The structure of fungal oxyluciferin was confirmed by counter synthesis.

MRMer, an interactive open source and cross-platform system for data extraction and visualization of multiple reaction monitoring experiments.

Science.gov (United States)

Martin, Daniel B; Holzman, Ted; May, Damon; Peterson, Amelia; Eastham, Ashley; Eng, Jimmy; McIntosh, Martin

2008-11-01

Multiple reaction monitoring (MRM) mass spectrometry identifies and quantifies specific peptides in a complex mixture with very high sensitivity and speed and thus has promise for the high throughput screening of clinical samples for candidate biomarkers. We have developed an interactive software platform, called MRMer, for managing highly complex MRM-MS experiments, including quantitative analyses using heavy/light isotopic peptide pairs. MRMer parses and extracts information from MS files encoded in the platform-independent mzXML data format. It extracts and infers precursor-product ion transition pairings, computes integrated ion intensities, and permits rapid visual curation for analyses exceeding 1000 precursor-product pairs. Results can be easily output for quantitative comparison of consecutive runs. Additionally MRMer incorporates features that permit the quantitative analysis experiments including heavy and light isotopic peptide pairs. MRMer is open source and provided under the Apache 2.0 license.

Predicting the optical observables for nucleon scattering on even-even actinides

Science.gov (United States)

Martyanov, D. S.; Soukhovitskiĩ, E. Sh.; Capote, R.; Quesada, J. M.; Chiba, S.

2017-09-01

The previously derived Lane consistent dispersive coupled-channel optical model for nucleon scattering on 232Th and 238U nuclei is extended to describe scattering on even-even actinides with Z = 90-98. A soft-rotator-model (SRM) description of the low-lying nuclear structure is used, where the SRM Hamiltonian parameters are adjusted to the observed collective levels of the target nucleus. SRM nuclear wave functions (mixed in K quantum number) have been used to calculate the coupling matrix elements of the generalized optical model. The “effective” deformations that define inter-band couplings are derived from the SRM Hamiltonian parameters. Conservation of nuclear volume is enforced by introducing a dynamic monopolar term to the deformed potential, leading to additional couplings between rotational bands. The fitted static deformation parameters are in very good agreement with those derived by Wang and collaborators using the Weizsäcker-Skyrme global mass model (WS4), allowing use of the latter to predict cross sections for nuclei without experimental data. A good description of the scarce “optical” experimental database is achieved. SRM couplings and volume conservation allow a precise calculation of the compound-nucleus formation cross sections, which is significantly different from that calculated with rigid-rotor potentials coupling the ground-state rotational band. The derived parameters can be used to describe both neutron- and proton-induced reactions. Supported by International Atomic Energy Agency, through the IAEA Research Contract 19263, by the Spanish Ministry of Economy and Competitivity under Contracts FPA2014-53290-C2-2-P and FPA2016-77689-C2-1-R.

Applied research on environmental pollution using INAA. A study on the environmental indicator analysis

Energy Technology Data Exchange (ETDEWEB)

Kim, Nak Bae; Lee, Gil Yong; Yoon, Yoon Yul; Chon, Sang Ki [Korea Institute of Geology Mining and Research, Taejon (Korea, Republic of)

1995-08-01

Among the many kinds of environmental indicator samples such as moss, lichen, pine needle, pine needle was selected as a bio-monitor and collected sample was divided two groups and one was washed with 1% hydrochloric acid to remove the elements deposited on surface. Trace elements in pine needle were analyzed by the decay time of each nuclide. Analytical accuracy was tested by analyzing NIST SRM 1575 pine needle. Results are follows: (1) Environmental indicator as a bio-monitor pine needle was selected. (2) The content difference of the trace elements between sampling period was monitored. And as content was varied with sampling time. (3) To monitor the influence of atmospheric deposition the surface of pine needle was washed with 1% hydrochloric acid. Therefore, As, Ce, La, Na, W, and Zn contents were decreased by washing. (4) Non-destructive INAA (Instrumental Neutron Activation Analysis) technique was developed for the determination of trace elements in environmental samples. (5) Analytical accuracy was tested by analyzing NIST SRM 1575 pine needle, and the accuracy was well agreed within 10% deviation. summarized. (author). 18 refs., 8 figs., 5 tabs.

The detection of iron protoporphyrin (heme b) in phytoplankton and marine particulate material by electrospray ionisation mass spectrometry – comparison with diode array detection

Energy Technology Data Exchange (ETDEWEB)

Gledhill, Martha, E-mail: m.gledhill@geomar.de

2014-09-02

Highlights: • Mass spectrometry was applied to the analysis of heme b in biological material. • Optimal conditions involved selective reactant monitoring of the heme b product ion. • The isotopic signature for this iron tetrapyrrole further improved selectivity. • Mass spectrometry and spectrophotometry were compared for heme b analysis. • Combining techniques made a powerful tool for analysis of heme in marine microbes. - Abstract: A mass spectrometric (MS) method for the identification of iron protoporphyrin (IX) (FePTP, heme b) in marine particulate material and phytoplankton is described. Electrospray ionisation of FePTP produced the molecular Fe(III)PTP{sup +} ion (m/z = 616) or the pseudomolecular [Fe(II)PTP + H]{sup +} ion (m/z = 617), depending on the oxidation state of the central iron ion. Collision induced dissociation (CID) in the ion trap mass spectrometer resulted in a single detected product ion (m/z = 557) indicative of loss of ethanoic acid from a carboxylic acid side chain. Widening the isolation width to 616 ± 3 resulted in production of a mass spectrum demonstrating the distinctive isotopic ratio of the iron containing fragment, further increasing the specificity of the analysis. Selective reactant monitoring (SRM) of the fragment ion (m/z = 557) was applied to the detection of FePTP after chromatography of ammoniacal OGP extracts of marine samples. The detection limit for FePTP analysed by SRM after chromatography was 1.2 ± 0.5 fmol. For phytoplankton samples, reasonably good agreement was achieved between results obtained with SRM and those obtained by monitoring absorbance at λ = 400 nm using a diode array detector (DAD). Use of SRM for analysis of particulate material obtained from the high latitude North Atlantic allowed for the analysis of FePTP in the presence of a co-eluting compound that interfered with detection by DAD. Simultaneous collection of mass spectra from m/z = 300 to 1500 resulted in identification of the

Development, validation and biomedical applications of stable-isotope dilution GC-MS and GC-MS/MS techniques for circulating malondialdehyde (MDA) after pentafluorobenzyl bromide derivatization: MDA as a biomarker of oxidative stress and its relation to 15(S)-8-iso-prostaglandin F2α and nitric oxide (NO).

Science.gov (United States)

Tsikas, Dimitrios; Rothmann, Sabine; Schneider, Jessica Y; Suchy, Maria-Theresia; Trettin, Arne; Modun, Darko; Stuke, Nadine; Maassen, Norbert; Frölich, Jürgen C

2016-04-15

Malondialdehyde (MDA, CH2(CHO)2) is one of the best investigated and most frequently measured biomarkers of lipid peroxidation in biological fluids, a constituent of the so called thiobarbituric acid reactive substances (TBARS). The reaction of thiobarbituric acid with MDA and other carbonyl compounds is the basis for the batch TBARS assay, one of the most commonly and widely used assays of oxidative stress. Yet, the TBARS assay lacks specificity even if combined with HPLC separation prior to visible absorbance or fluorescence detection. In this article, we report highly specific and sensitive stable-isotope dilution GC-MS and GC-MS/MS methods for the quantitative determination of MDA in human plasma (0.1 mL). These methods utilize the acidity (pKa, 4.46) of the two methylene H protons of MDA in aqueous solution, which are as acidic as acetic acid. Endogenous MDA in native plasma and the externally added internal standard [1,3-(2)H2]-MDA (d2-MDA, CH2(CDO)2) are derivatized in aqueous acetone (400 μL) with pentafluorobenzyl (PFB) bromide (10 μL). The reaction products were identified as C(PFB)2(CHO)2 (molecular weight, 432) and C(PFB)2(CDO)2) (molecular weight, 434), respectively. After solvent extraction with toluene (1 mL) quantification is performed by selected-ion monitoring (SIM) in GC-MS and by selected-reaction monitoring (SRM) in GC-MS/MS in the electron-capture negative-ion chemical ionization (ECNICI) mode. In the SIM mode, the anions [M-PFB](-) at m/z 251 for MDA and m/z 253 for d2-MDA are detected. In the SRM mode, the mass transitions m/z 251 to m/z 175 for MDA and m/z 253 to m/z 177 for d2-MDA are monitored. The method was thoroughly validated in human plasma. Potential interfering substances including anticoagulants and commercially available monovettes commonly used for blood sampling were tested. The lowest MDA concentrations were measured in serum followed by heparinized and EDTA plasma. The GC-MS and GC-MS/MS methods were found to be specific

A review of isotopic composition as an indicator of the natural and anthropogenic behavior of mercury

International Nuclear Information System (INIS)

Ridley, W. Ian; Stetson, Sarah J.

2006-01-01

There are seven stable isotopes of Hg that can be fractionated as a result of inorganic and organic interactions. Important inorganic reactions involve speciation changes resulting from variations in environmental redox conditions, and phase changes resulting from variations in temperature and/or atmospheric pressure. Important organic reactions include methylation and demethylation, reactions that are bacterially mediated, and complexing with organic anions in soils. The measurement of Hg isotopes by multi-collector-inductively coupled plasma-mass spectrometry (MC-ICP-MS) is now sufficiently precise and sensitive that it is potentially possible to develop the systematics of Hg isotopic fractionation. This provides an opportunity to evaluate the utility of Hg isotopes in identifying source processes, transport mechanisms, and sinks. New values are provided for, 201 Hg/ 198 Hg, 200 Hg/ 198 Hg, 199 Hg/ 198 Hg for three standard materials (IRMM-AE639, SRM 1641c, SRM 3133) that can be used to make inter-laboratory data comparisons, and these values are tabulated with published isotopic information. Overall, the isotopic data for these standards agree to approximately 0.2 per mille . The paper reviews Hg isotope studies that deal with hydrothermal ore deposits, sediments, coal and organic complexing

A simple optimized microwave digestion method for multielement monitoring in mussel samples

International Nuclear Information System (INIS)

Saavedra, Y.; Gonzalez, A.; Fernandez, P.; Blanco, J.

2004-01-01

With the aim of obtaining a set of common decomposition conditions allowing the determination of several metals in mussel tissue (Hg by cold vapour atomic absorption spectrometry; Cu and Zn by flame atomic absorption spectrometry; and Cd, PbCr, Ni, As and Ag by electrothermal atomic absorption spectrometry), a factorial experiment was carried out using as factors the sample weight, digestion time and acid addition. It was found that the optimal conditions were 0.5 g of freeze-dried and triturated samples with 6 ml of nitric acid and subjected to microwave heating for 20 min at 180 psi. This pre-treatment, using only one step and one oxidative reagent, was suitable to determine the nine metals studied with no subsequent handling of the digest. It was possible to carry out the determination of atomic absorption using calibrations with aqueous standards and matrix modifiers for cadmium, lead, chromium, arsenic and silver. The accuracy of the procedure was checked using oyster tissue (SRM 1566b) and mussel tissue (CRM 278R) certified reference materials. The method is now used routinely to monitor these metals in wild and cultivated mussels, and found to be good

Detection and differentiation of 22kDa and 20kDa Growth Hormone proteoforms in human plasma by LC-MS/MS

DEFF Research Database (Denmark)

Sanmartín, Gerard Such; Bache, N.; Bosch, J.

2015-01-01

Human growth hormone (GH) is suspected to be widely and illegally used in sport to improve athletes' performance. For the detection of GH abuse, blood samples are screened for abnormal ratios between the 22 and 20kDa GH proteoforms that demonstrate the administration of the synthetic hormone....... Current detection methods are based on classical immunoassays as they provide sufficient sensitivity for the detection of GH proteoforms. These antibody based methods, however, suffer from unclear selectivity and potential cross-reactivity towards similar proteins. For unambiguous GH detection, we report...... a Mass Spectrometry ImmunoAssay (MSIA) that first enriches GH from plasma with an antibody of relatively low specificity, and subsequently quantifies the 22 and 20kDa proteoforms by Selected Reaction Monitoring (SRM) LC-MS/MS analysis. This method proved superior to an antibody-free strategy based on GH...

Excited state intramolecular charge transfer reaction in 4-(1 ...

Indian Academy of Sciences (India)

Administrator

cal reactions to the determination of paleotempera- tures from isotopic ... ordered liquid than H2O due to stronger H-bond in- teractions in the deuterated water ... layer chromatography and monitoring the excitation wavelength dependence of ...

Certification of total arsenic in blood and urine standard reference materials by radiochemical neutron activation analysis and inductively coupled plasma-mass spectrometry

International Nuclear Information System (INIS)

Paul, R.L.; Clay Davis, W.; Lee Yu; Murphy, K.E.; Bryan, C.E.; Vetter, T.W.; Guthrie, W.F.; Leber, D.D.; Gulchekhra Shakirova; Graylin Mitchell

2014-01-01

Radiochemical neutron activation analysis (RNAA) was used to measure arsenic at four levels in standard reference material (SRM) 955c Toxic Elements in Caprine Blood and at two levels in SRM 2668 Toxic Elements in Frozen Human Urine for the purpose of providing mass concentration values for certification. Samples were freeze-dried prior to analysis followed by neutron irradiation for 3 h at a fluence rate of 1 × 10 14 cm -2 s -1 . After sample dissolution in perchloric and nitric acids, arsenic was separated from the matrix either by retention on hydrated manganese dioxide (urine) or by extraction into zinc diethyldithiocarbamate in chloroform (blood). 76 As was quantified by gamma-ray spectroscopy. Differences in chemical yield and counting geometry between samples and standards were monitored by measuring the count rate of a 77 As tracer added before sample dissolution. RNAA results were combined with inductively coupled plasma-mass spectrometry values from National Institute of Standards and Technology and collaborating laboratories to provide certified values of 10.81 ± 0.54 and 213.1 ± 0.73 μg/L for SRM 2668 Levels I and II, and certified values of 21.66 ± 0.73, 52.7 ± 1.1, and 78.8 ± 4.9 μg/L for SRM 955c Levels II-IV, respectively. Because of discrepancies between values obtained by different methods for SRM 955c Level I, an information value of <5 μg/L was assigned for this material. (author)

Development of monitoring and control technology based on trace gas monitoring. Final report

Energy Technology Data Exchange (ETDEWEB)

Liebowitz, B.

1997-07-01

Trace gases are generated by many biological reactions. During anaerobic decomposition, trace levels of hydrogen (H{sub 2}) and carbon monoxide (CO) gases are produced. It was shown previously that these trace gases are intrinsically related to the biochemical reactions occurring and, therefore, offer promise for on-line process monitoring and control. This work was designed to test how effectively hydrogen and CO could be to monitor high-rate anaerobic systems that has significant mass transfer and complex hydraulics. An experimental program was designed to examine the behavior of an upflow anaerobic sludge blanket (UASB) reactor system under steady state and in response to organic loading perturbations. The responses of trace gases CO and H{sub 2} were tracked using an on-line, real-time gas-monitoring system linked to a computer-controlled data acquisition package. Data on conventional process parameters such as pH, chemical oxygen demand (COD), volatile fatty acids (VFAs) were concurrently collected. Monitoring of conventional process indicators (i.e., pH, VFA, gas production) and trace gas (H{sub 2} and CO) indicators was conducted using a matrix of nine different steady-state OLRs (4-23 kg COD/m{sup 3} -d) and system HRTs (0.5 to 2.5 days) was performed to determine any correlation among the indicators. Of OLR, HRT, and influent COD, only OLR had any significant influence on the process indicators examined. All parameters except methane increased with increases in OLR; methane decreased with increased OLR. The OLR and gas production rate (GP) were observed to be linearly correlated.

Synthesis and Activity Test of Cu/ZnO/Al2O3 for the Methanol Steam Reforming as a Fuel Cell’s Hydrogen Supplier

Directory of Open Access Journals (Sweden)

IGBN Makertihartha

2009-05-01

Full Text Available The synthesis of hydrogen from hydrocarbons through the steam reforming of methanol on Cu/ZnO/Al2O3 catalyst has been investigated. This process is assigned to be one of the promising alternatives for fuel cell hydrogen process source. Hydrogen synthesis from methanol can be carried out by means of methanol steam reforming which is a gas phase catalytic reaction between methanol and water. In this research, the Cu/ZnO/Al2O3 catalyst prepared by the dry impregnation was used. The specific surface area of catalyst was 194.69 m2/gram.The methanol steam reforming (SRM reaction was carried out by means of the injection of gas mixture containing methanol and water with 1:1.2 mol ratio and 20-90 mL/minute feed flow rate to a fixed bed reactor loaded by 1 g of catalyst. The reaction temperature was 200-300 °C, and the reactor pressure was 1 atm. Preceding the reaction, catalyst was reduced in the H2/N2 mixture at 160 °C. This study shows that at 300 °C reaction temperature, methanol conversion reached 100% at 28 mL/minute gas flow rate. This conversion decreased significantly with the increase of gas flow rate. Meanwhile, the catalyst prepared for SRM was stable in 36 hours of operation at 260 °C. The catalyst exhibited a good stability although the reaction condition was shifted to a higher gas flow rate.

Method and apparatus for controlling gas evolution from chemical reactions

Science.gov (United States)

Skorpik, James R.; Dodson, Michael G.

1999-01-01

The present invention is directed toward monitoring a thermally driven gas evolving chemical reaction with an acoustic apparatus. Signals from the acoustic apparatus are used to control a heater to prevent a run-away condition. A digestion module in combination with a robotic arm further automate physical handling of sample material reaction vessels. The invention is especially useful for carrying out sample procedures defined in EPA Methods SW-846.

MALDI MS-based Composition Analysis of the Polymerization Reaction of Toluene Diisocyanate (TDI) and Ethylene Glycol (EG).

Science.gov (United States)

Ahn, Yeong Hee; Lee, Yeon Jung; Kim, Sung Ho

2015-01-01

This study describes an MS-based analysis method for monitoring changes in polymer composition during the polyaddition polymerization reaction of toluene diisocyanate (TDI) and ethylene glycol (EG). The polymerization was monitored as a function of reaction time using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI TOF MS). The resulting series of polymer adducts terminated with various end-functional groups were precisely identified and the relative compositions of those series were estimated. A new MALDI MS data interpretation method was developed, consisting of a peak-resolving algorithm for overlapping peaks in MALDI MS spectra, a retrosynthetic analysis for the generation of reduced unit mass peaks, and a Gaussian fit-based selection of the most prominent polymer series among the reconstructed unit mass peaks. This method of data interpretation avoids errors originating from side reactions due to the presence of trace water in the reaction mixture or MALDI analysis. Quantitative changes in the relative compositions of the resulting polymer products were monitored as a function of reaction time. These results demonstrate that the mass data interpretation method described herein can be a powerful tool for estimating quantitative changes in the compositions of polymer products arising during a polymerization reaction.

Hairpin stabilized fluorescent silver nanoclusters for quantitative detection of NAD+ and monitoring NAD+/NADH based enzymatic reactions.

Science.gov (United States)

Jain, Priyamvada; Chakma, Babina; Patra, Sanjukta; Goswami, Pranab

2017-03-01

A set of 90 mer long ssDNA candidates, with different degrees of cytosine (C-levels) (% and clusters) was analyzed for their function as suitable Ag-nanocluster (AgNC) nucleation scaffolds. The sequence (P4) with highest C-level (42.2%) emerged as the only candidate supporting the nucleation process as evident from its intense fluorescence peak at λ 660 nm . Shorter DNA subsets derived from P4 with only stable hairpin structures could support the AgNC formation. The secondary hairpin structures were confirmed by PAGE, and CD studies. The number of base pairs in the stem region also contributes to the stability of the hairpins. A shorter 29 mer sequence (Sub 3) (ΔG = -1.3 kcal/mol) with 3-bp in the stem of a 7-mer loop conferred highly stable AgNC. NAD + strongly quenched the fluorescence of Sub 3-AgNC in a concentration dependent manner. Time resolved photoluminescence studies revealed the quenching involves a combined static and dynamic interaction where the binding constant and number of binding sites for NAD + were 0.201 L mol -1 and 3.6, respectively. A dynamic NAD + detection range of 50-500 μM with a limit of detection of 22.3 μM was discerned. The NAD + mediated quenching of AgNC was not interfered by NADH, NADP + , monovalent and divalent ions, or serum samples. The method was also used to follow alcohol dehydrogenase and lactate dehydrogenase catalyzed physiological reactions in a turn-on and turn-off assay, respectively. The proposed method with ssDNA-AgNC could therefore be extended to monitor other NAD + /NADH based enzyme catalyzed reactions in a turn-on/turn-off approach. Copyright © 2016 Elsevier B.V. All rights reserved.

Clozapine-associated extrapyramidal reaction.

Science.gov (United States)

Elliott, E S; Marken, P A; Ruehter, V L

2000-05-01

To report a case of extrapyramidal reaction associated with a dosage increase of clozapine. A 44-year-old white man with a 20-year history of chronic paranoid schizophrenia was admitted to an inpatient psychiatric facility. His prior medications restarted on admission were clozapine 650 mg at bedtime, haloperidol 10 mg at bedtime, clonazepam 2 mg/d, and aspirin 325 mg/d. Two days after admission (hospital day 3), clozapine and clonazepam were discontinued, and he was prescribed haloperidol 5 mg every morning and 10 mg every evening. Stabilization occurred over the following 24 days, with progressively lower dosages of haloperidol and increasing dosages of clozapine. Haloperidol was discontinued on day 24. On day 47, the patient was agitated and making bizarre statements; thus, the morning dose of clozapine was increased by 50 mg (total 450 mg/d). On day 48 at 2200, a dystonic reaction was diagnosed; he received intramuscular diphenhydramine 50 mg, which caused the reaction to subside. At the time of the adverse reaction, he was prescribed clozapine 450 mg/d, vitamin E 400 IU three times daily, aspirin 325 mg/d, and acetaminophen, milk of magnesia, and Maalox as needed. Although the risk of extrapyramidal symptoms (EPS) is significantly lower with clozapine than with conventional agents, elevated clozapine blood concentrations have been reported to cause EPS; other reports have cited severe dystonias and dyskinesias on abrupt clozapine withdrawal. Considering the medications prescribed at the time and the discontinuation of haloperidol 24 days before the event, clozapine was the most likely cause of the extrapyramidal reaction. Regardless of anticipated safety associated with novel antipsychotics such as clozapine, reports of dystonic reactions must be taken into account and patients monitored appropriately.

CDC28, NETI, and HFII are required for checkpoints in Saccharomyces cerevisiae

International Nuclear Information System (INIS)

Koltovaya, N.A.; Kadyshevskaya, E.Yu.; Roshina, M.P.; Devin, A.B.

2009-01-01

The involvement of SRM genes selected as genes affecting genetic stability and radiosensitivity in a cell cycle arrest under the action of damaging agents was studied. It was shown that the srm5/cdc28-srm, srm8/netI-srm, and srmI2/hfiI-srm mutations prevent checkpoint activation by DNA damage, particularly the G 0 /S (srm5, srm8), G 1 /S (srm5, srm8, srm12), S (srm8, srm12) and S/G 2 (srm5) checkpoints. It seems that in budding yeast the CDC28, HFII/ADAI, and NETI genes mediate cellular response induced by DNA damage with checkpoint control. The well-known checkpoint-genes RAD9, RAD17, RAD24, and RAD53, and the genes CDC28, and NETI have been found to belong to one epistasis group named RAD9-group as regards cell sensitivity to γ radiation. An analysis of the radiosensitivity of double mutants has revealed that the mutation cdc-28-srm is hypostatic to each of mutations rad9Δ, and rad24Δ, and additive to rad17Δ. The mutation netI-srm is hypostatic to the mutations rad9Δ but additive to rad17Δ, rad24Δ, and rad53. The mutation hfiI-srm has an additive effect in compound with the mutations rad24Δ and rad9Δ. So, investigations of epistatic interactions have demonstrated a branched RAD9-dependent pathway. The analyzed genes can also participate in a minor mechanism involved in determining cell radiation sensitivity independently of the mentioned RAD9-dependent pathway

In-situ electrical analysis in view of monitoring the processing of thermoplastics

Science.gov (United States)

Gonnet, J. M.; Guillet, J.; Ainser, A.; Boiteux, G.; Fulchiron, R.; Seytre, Gerard

1999-12-01

In the last recent years, electrical techniques like microdielectrometry have presented an attracting and increasing interest for continuous monitoring, in a nondestructive way, of the advancement of the reaction of thermoset resins under cure. We think that the use of electrical analysis for in situ monitoring of chemical reactions can be extended to get information on thermoplastic and the physical phenomena such sa crystallization or study of residence time distribution in processing machines such as extruders.

Quantification of 8-α-hydroxy-mutilin as marker residue for tiamulin in rabbit tissues by high-performance liquid chromatography-mass spectrometry.

Science.gov (United States)

De Baere, Siegrid; Devreese, Mathias; Maes, An; De Backer, Patrick; Croubels, Siska

2015-06-01

For the first time, a sensitive and specific method was developed and fully validated for the quantification of the EU marker residue of tiamulin, 8-α-hydroxy-mutilin, in rabbit muscle and liver tissues using liquid chromatography combined with positive heated electrospray ionization triple quadrupole mass spectrometry. The mass spectrometer was operated in the selected reaction monitoring (SRM) mode with selection of the [M + H](+) ion in both quadrupoles 1 and 3, resulting in the SRM transition m/z 337.25 > 337.25 for quantification. Chromatography was performed using a Hypersil Gold C18 column using a gradient elution program with water and methanol as mobile phases. The sample preparation procedure for the analysis of 8-α-hydroxy-mutilin in liver and muscle samples consisted of three main steps: (1) extraction of the tissue matrix using 0.1 N hydrochloric acid/acetone (50/50, v/v), (2) hydrolysis of tiamulin and metabolites to 8-α-hydroxy-mutilin in alkaline medium at 45 °C, and (3) liquid-liquid extraction in acidic medium using ethyl acetate. This is the first method presenting fully validated results, encompassing a linearity of 50 to 2,000 μg/kg, within-run and between-run accuracy and precision, limit of quantification (50 μg/kg for both muscle and liver tissues), limit of detection (muscle, 11.9 μg/kg; liver, 20.6 μg/kg), extraction recovery (muscle, 66.2%; liver, 75.5%), signal suppression and enhancement (muscle, 51.7%; liver, 43.3%), carryover, applicability and practicability, and stability during storage and analysis. This novel method is therefore sensitive enough to be used for residue depletion studies of tiamulin in rabbits and for food safety monitoring with respect to MRL compliance of residues.

Quantitative optical diagnostics in pathology recognition and monitoring of tissue reaction to PDT

Science.gov (United States)

Kirillin, Mikhail; Shakhova, Maria; Meller, Alina; Sapunov, Dmitry; Agrba, Pavel; Khilov, Alexander; Pasukhin, Mikhail; Kondratieva, Olga; Chikalova, Ksenia; Motovilova, Tatiana; Sergeeva, Ekaterina; Turchin, Ilya; Shakhova, Natalia

2017-07-01

Optical coherence tomography (OCT) is currently actively introduced into clinical practice. Besides diagnostics, it can be efficiently employed for treatment monitoring allowing for timely correction of the treatment procedure. In monitoring of photodynamic therapy (PDT) traditionally employed fluorescence imaging (FI) can benefit from complementary use of OCT. Additional diagnostic efficiency can be derived from numerical processing of optical diagnostics data providing more information compared to visual evaluation. In this paper we report on application of OCT together with numerical processing for clinical diagnostic in gynecology and otolaryngology, for monitoring of PDT in otolaryngology and on OCT and FI applications in clinical and aesthetic dermatology. Image numerical processing and quantification provides increase in diagnostic accuracy. Keywords: optical coherence tomography, fluorescence imaging, photod

Importance of MS selectivity and chromatographic separation in LC-MS/MS-based methods when investigating pharmaceutical metabolites in water. Dipyrone as a case of study.

Science.gov (United States)

Ibáñez, M; Gracia-Lor, E; Sancho, J V; Hernández, F

2012-08-01

Pharmaceuticals are emerging contaminants of increasing concern because of their presence in the aquatic environment and potential to reach drinking-water sources. After human and/or veterinary consumption, pharmaceuticals can be excreted in unchanged form, as the parent compound, and/or as free or conjugated metabolites. Determination of most pharmaceuticals and metabolites in the environment is commonly made by liquid chromatography (LC) coupled to mass spectrometry (MS). LC coupled to tandem MS is the technique of choice nowadays in this field. The acquisition of two selected reaction monitoring (SRM) transitions together with the retention time is the most widely accepted criterion for a safe quantification and confirmation assay. However, scarce attention is normally paid to the selectivity of the selected transitions as well as to the chromatographic separation. In this work, the importance of full spectrum acquisition high-resolution MS data using a hybrid quadrupole time-of-flight analyser and/or a suitable chromatographic separation (to reduce the possibility of co-eluting interferences) is highlighted when investigating pharmaceutical metabolites that share common fragment ions. For this purpose, the analytical challenge associated to the determination of metabolites of the widely used analgesic dipyrone (also known as metamizol) in urban wastewater is discussed. Examples are given on the possibilities of reporting false positives of dypirone metabolites by LC-MS/MS under SRM mode due to a wrong assignment of identity of the compounds detected. Copyright © 2012 John Wiley & Sons, Ltd.

Single-laboratory validation of a high-performance liquid chromatographic-diode array detector-fluorescence detector/mass spectrometric method for simultaneous determination of water-soluble vitamins in multivitamin dietary tablets.

Science.gov (United States)

Chen, Pei; Atkinson, Renata; Wolf, Wayne R

2009-01-01

The purpose of this study was to develop a single-laboratory validated (SLV) method using high-performance liquid chromatography with different detectors [diode array detector (DAD); fluorescence detector (FLD); and mass spectrometry (MS)] for determination of 7 B-complex vitamins (B1-thiamin, B2-riboflavin, B3-nicotinamide, B6-pyridoxine, B9-folic acid, pantothenic acid, and biotin) and vitamin C in multivitamin/multimineral dietary supplements. The method involves the use of a reversed-phase octadecylsilyl column (4 microm, 250 x 2.0 mm id) and a gradient mobile phase profile. Gradient elution was performed at a flow rate of 0.25 mL/min. After a 5 min isocratic elution at 100% A (0.1% formic acid in water), a linear gradient to 50% A and 50% B (0.1% formic acid in acetonitrile) at 15 min was employed. Detection was performed with a DAD as well as either an FLD or a triple-quadrupole MS detector in the multiple reaction monitoring mode. SLV was performed using Standard Reference Material (SRM) 3280 Multivitamin/Multimineral Tablets, being developed by the National Institute of Standards and Technology, with support by the Office of Dietary Supplements of the National Institutes of Health. Phosphate buffer (10 mM, pH 2.0) extracts of the NIST SRM 3280 were analyzed by the liquid chromatographic (LC)-DAD-FLDIMS method. Following extraction, the method does not require any sample cleanup/preconcentration steps except centrifugation and filtration.

Site-specific growth of Au-Pd alloy horns on Au nanorods: A platform for highly sensitive monitoring of catalytic reactions by surface enhancement raman spectroscopy

KAUST Repository

Huang, Jianfeng

2013-06-12

Surface-enhanced Raman scattering (SERS) is a highly sensitive probe for molecular detection. The aim of this study was to develop an efficient platform for investigating the kinetics of catalytic reactions with SERS. To achieve this, we synthesized a novel Au-Pd bimetallic nanostructure (HIF-AuNR@AuPd) through site-specific epitaxial growth of Au-Pd alloy horns as catalytic sites at the ends of Au nanorods. Using high-resolution electron microscopy and tomography, we successfully reconstructed the complex three-dimensional morphology of HIF-AuNR@AuPd and identified that the horns are bound with high-index {11l} (0.25 < l < 0.43) facets. With an electron beam probe, we visualized the distribution of surface plasmon over the HIF-AuNR@AuPd nanorods, finding that strong longitudinal surface plasmon resonance concentrated at the rod ends. This unique crystal morphology led to the coupling of high catalytic activity with a strong SERS effect at the rod ends, making HIF-AuNR@AuPd an excellent bifunctional platform for in situ monitoring of surface catalytic reactions. Using the hydrogenation of 4-nitrothiophenol as a model reaction, we demonstrated that its first-order reaction kinetics could be accurately determined from this platform. Moreover, we clearly identified the superior catalytic activity of the rod ends relative to that of the rod bodies, owing to the different SERS activities at the two positions. In comparison with other reported Au-Pd bimetallic nanostructures, HIF-AuNR@AuPd offered both higher catalytic activity and greater detection sensitivity. © 2013 American Chemical Society.

Sub-ensemble monitoring of DNA strand displacement using multiparameter single-molecule FRET

OpenAIRE

Baltierra Jasso, Laura; Morten, Michael; Magennis, Steven William

2018-01-01

Non-enzymatic DNA strand displacement is an important mechanism in dynamic DNA nanotechnology. Here we show that the large parameter space that is accessible by single-molecule FRET is ideal for the simultaneous monitoring of multiple reactants and products of DNA strand exchange reactions. We monitored the strand displacement from double-stranded DNA (dsDNA) by single-stranded DNA (ssDNA) at 37 °C; the data were modelled as a second-order reaction approaching equilibrium, with a rate constan...

Cutaneous adverse drug reactions in a tertiary care teaching hospital in India: An intensive monitoring study

Directory of Open Access Journals (Sweden)

Sejal Thakkar

2017-01-01

Full Text Available Background: The epidemiological data based on intensive monitoring studies are limited for the cutaneous adverse drug reactions (CADRs in terms of incidence. Most of earlier Indian studies focused only on types and causative drugs of CADRs. Aim: The aim of this study is to analyze the CADRs with reference to the incidence, its subgroup analysis, causative drugs, and other clinical characteristics in Indian population. Methodology: Intensive monitoring study was carried out over a period of 3 years in the dermatology outpatient and inpatient department. CADRs due to only systematically administered drugs were considered. The WHO definition for CADR, the WHO causality definitions, modified Schumock and Thornton's criteria for preventability, and International Conference on Harmonisation E2A guidelines for seriousness were considered. Incidence was expressed in percentage and its 95% confidence interval. The incidence was analyzed on basis of characteristics of study population and CADRs. Results: A total of 171 CADRs were observed from 37,623 patients. The CADR incidence was 0.45% (95% CI: 0.39–0.53. The incidence did not significantly differ in different age groups and gender. Commonly observed CADRs were maculopapular rash (23.98%, urticaria (21.64%, and fixed drug eruptions (FDEs (18.13%. Antimicrobials (35.18% and nonsteroidal anti-inflammatory drugs (NSAIDs were suspected in all common CADRs. Anti-infective and NSAIDs were most commonly suspected drugs in overall CADRs, maculopapular rash, urticaria, FDEs, and erythema multiforme. The exact nature of drugs remained inaccessible in one-fourth cases due to use of the over-the-counter self-medications. The incidence of preventable and serious and fatal CADRs was 0.08% (95% CI: 0.05–0.11, 0.04% (95% CI: 0.02–0.06, and 0.003% (95% CI: 0.000–0.001, respectively. Conclusion: Ethnic characteristics should be considered while interpreting incidence from the international studies. The

Reaction of uranium and the fluorocarbon FC-75

Science.gov (United States)

Young, R. H.

1985-04-01

Because of criticality concerns with water cooling in enriched uranium upgrading, a fluorocarbon has been evaluated as a replacement coolant for internal module components in the Plasma Separation Process (PSP). The interaction of bulk uranium and of powdered uranium with FC-75 has been investigated at temperatures between 200 and 700 C. The gas pressure and the metal temperature were monitored as a function of time. Modest temperature changes of 50 to 100 C were observed for the bulk uranium/fluorocarbon reaction. Much larger changes (up to 1000 C) were noted for the reaction involving high surface area uranium powder. These temperature transients, particularly for the powdered uranium reaction, were short-lived ( 10 seconds) and indicative of the formation of a protective layer of reaction products. Analysis of residual gas products by infrared spectroscopy indicated that one potentially serious hazard, UF6, was not present; however, several small toxic fluorocarbons were produced by thermolysis and/or reaction. X-ray diffraction analysis of the residual solids indicated UF4 and UO2 were the major solid products.

YPED: an integrated bioinformatics suite and database for mass spectrometry-based proteomics research.

Science.gov (United States)

Colangelo, Christopher M; Shifman, Mark; Cheung, Kei-Hoi; Stone, Kathryn L; Carriero, Nicholas J; Gulcicek, Erol E; Lam, TuKiet T; Wu, Terence; Bjornson, Robert D; Bruce, Can; Nairn, Angus C; Rinehart, Jesse; Miller, Perry L; Williams, Kenneth R

2015-02-01

We report a significantly-enhanced bioinformatics suite and database for proteomics research called Yale Protein Expression Database (YPED) that is used by investigators at more than 300 institutions worldwide. YPED meets the data management, archival, and analysis needs of a high-throughput mass spectrometry-based proteomics research ranging from a single laboratory, group of laboratories within and beyond an institution, to the entire proteomics community. The current version is a significant improvement over the first version in that it contains new modules for liquid chromatography-tandem mass spectrometry (LC-MS/MS) database search results, label and label-free quantitative proteomic analysis, and several scoring outputs for phosphopeptide site localization. In addition, we have added both peptide and protein comparative analysis tools to enable pairwise analysis of distinct peptides/proteins in each sample and of overlapping peptides/proteins between all samples in multiple datasets. We have also implemented a targeted proteomics module for automated multiple reaction monitoring (MRM)/selective reaction monitoring (SRM) assay development. We have linked YPED's database search results and both label-based and label-free fold-change analysis to the Skyline Panorama repository for online spectra visualization. In addition, we have built enhanced functionality to curate peptide identifications into an MS/MS peptide spectral library for all of our protein database search identification results. Copyright © 2015 The Authors. Production and hosting by Elsevier Ltd.. All rights reserved.

Detection of seventy-two anabolic and androgenic steroids and/or their esters in horse hair using ultra-high performance liquid chromatography-high resolution mass spectrometry in multiplexed targeted MS2 mode and gas chromatography-tandem mass spectrometry.

Science.gov (United States)

Choi, Timmy L S; Kwok, Karen Y; Kwok, Wai Him; Tsoi, Yeuki Y K; Wong, Jenny K Y; Wan, Terence S M

2018-06-20

Anabolic and androgenic steroids (AAS) are banned substances in both human and equine sports. They are often administered intramuscularly to horses in esterified forms for the purpose of extending their time of action. The authors' laboratory has previously reported an UHPLC/HRMS method using quadrupole-Orbitrap mass spectrometer in full scan and parallel reaction monitoring (PRM) mode for the detection of 48 AAS and/or their esters in horse hair. However, two injections were required due to the long duty cycle time. In this paper, an UHPLC/HRMS method using multiplexed targeted MS 2 mode was developed and validated to improve the coverage to 65 AAS and/or their esters in a single injection. In addition, a GC/MS/MS method in selected reaction monitoring (SRM) mode was developed to screen for another seven AAS and/or their esters not adequately covered by the UHPLC/HRMS method using the same sample extract after derivatisation with pentafluoropropionic anhydride. The UHPLC/HRMS and GC/MS/MS methods in combination allowed the detection of 72 AAS and/or their esters with estimated limits of detection down to sub to low ppb levels with good interday precision. Method applicability was demonstrated by the detection of boldione and 4-androstenedione in two out-of-competition hair samples and testosterone propionate in a referee hair sample. Copyright © 2018 Elsevier B.V. All rights reserved.

Determination of the enantiomer ratio of PBB 149 by GC/NICI-tandem mass spectrometry in the selected reaction monitoring mode

Energy Technology Data Exchange (ETDEWEB)

Recke, R. von der; Goetsch, A.; Vetter, W. [Hohenheim Univ., Stuttgart (Germany). Inst. fuer Lebensmittelchemie; Mariussen, E. [Norwegian Inst. for Air Research, Kjeller (Norway); Berger, U.; Herzke, D. [NILU, The Polar Environmental Centre, Tromso (Norway)

2004-09-15

Technical mixtures of polybrominated biphenyls (PBBs) have been extensively used as flameretardants in textile and electronic industries and as additives in plastics. Despite a continuous reduction of the worldwide annual production in the last decade, the presence of PBBs in the environment was recently confirmed in a wide range of samples. PBBs exist in a theoretical variety of 209 congeners. Many di-ortho, tri-ortho, and tetra-ortho PBBs form stable pairs of enantiomers, which was experimentally confirmed by enantioselective HPLC separation of chiral PBB in a technical mixture. It is known from the literature, that chiral organohalogen compounds can be degraded enantioselectively. In this work we used a chiral GC stationary phase and developed a method using GC/NICI-MSMS in the single reaction monitoring mode for the determination of the enantioratio of PBB 149 in extracts from Norwegian bird of prey eggs.

Now day methods for heavy ion monitoring

International Nuclear Information System (INIS)

Luk'yanov, S.M.; Penionzhkevich, Yu.Eh.; Chubaryan, G.G.

1984-01-01

Up-to-date methods for identification of products yield as a result of heavy ion interaction with nuclei are described. Monitoring of total ionization has been realized by gas-filled ionization chambers semiconductor detectors, scintillators. A method for specific ionization loss monitoring and time-of-flight technique for heavy-ion mass identification are considered. Advantages of the method for identification of nuclear reaction prodUcts by means of a magnetic analyzer are displayed

The concept of adverse drug reaction reporting: awareness among ...

African Journals Online (AJOL)

Arun Kumar Agnihotri

concept of pharmacovigilance and adverse drug reaction reporting, a section on ... ADR go undocumented worldwide8,9. ... international drug monitoring collaborating centre, ... practitioners to report all suspected ADR, the few .... more with some of the guidelines such as nurses, .... patients: a meta-analysis of prospective.

Tritiated-water detection with a 2D(γ,n)1H monitor

International Nuclear Information System (INIS)

Winn, W.G.; Baumann, N.P.

Tritiated process water is monitored by detecting the D 2 O component via the 2 D(γ,n) 1 H reaction. A probe containing a 1 to 7 mCi 24 Na (15 h) γ-source and six 3 He neutron detectors produces and monitors the 2 D(γ,n) 1 H reaction. A variety of probe configurations were examined for D 2 O detection sensitivity. The corresponding detection limits range from 6 to 280 μL for D 2 O droplets and 1 to 13 μL/cm for D 2 O streams, when 10-minute neutron counting with a 1 mCi γ-source is used. Results from two field applications illustrate the utility of the monitor

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

International Nuclear Information System (INIS)

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

2011-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2011-10-17

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

Mass Spectrometry-based Assay for High Throughput and High Sensitivity Biomarker Verification

Energy Technology Data Exchange (ETDEWEB)

Guo, Xuejiang; Tang, Keqi

2017-06-14

Searching for disease specific biomarkers has become a major undertaking in the biomedical research field as the effective diagnosis, prognosis and treatment of many complex human diseases are largely determined by the availability and the quality of the biomarkers. A successful biomarker as an indicator to a specific biological or pathological process is usually selected from a large group of candidates by a strict verification and validation process. To be clinically useful, the validated biomarkers must be detectable and quantifiable by the selected testing techniques in their related tissues or body fluids. Due to its easy accessibility, protein biomarkers would ideally be identified in blood plasma or serum. However, most disease related protein biomarkers in blood exist at very low concentrations (<1ng/mL) and are “masked” by many none significant species at orders of magnitude higher concentrations. The extreme requirements of measurement sensitivity, dynamic range and specificity make the method development extremely challenging. The current clinical protein biomarker measurement primarily relies on antibody based immunoassays, such as ELISA. Although the technique is sensitive and highly specific, the development of high quality protein antibody is both expensive and time consuming. The limited capability of assay multiplexing also makes the measurement an extremely low throughput one rendering it impractical when hundreds to thousands potential biomarkers need to be quantitatively measured across multiple samples. Mass spectrometry (MS)-based assays have recently shown to be a viable alternative for high throughput and quantitative candidate protein biomarker verification. Among them, the triple quadrupole MS based assay is the most promising one. When it is coupled with liquid chromatography (LC) separation and electrospray ionization (ESI) source, a triple quadrupole mass spectrometer operating in a special selected reaction monitoring (SRM) mode

Bimetallic Nanocatalysts in Mesoporous Silica for Hydrogen Production from Coal-Derived Fuels

Energy Technology Data Exchange (ETDEWEB)

Kuila, Debasish [North Carolina Agricultural & Technical State Univ., Greensboro, NC (United States); Ilias, Shamsuddin [North Carolina Agricultural & Technical State Univ., Greensboro, NC (United States)

2013-02-13

In steam reforming reactions (SRRs) of alkanes and alcohols to produce H₂, noble metals such as platinum (Pt) and palladium (Pd) are extensively used as catalyst. These metals are expensive; so, to reduce noble-metal loading, bi-metallic nanocatalysts containing non-noble metals in MCM-41 (Mobil Composition of Material No. 41, a mesoporous material) as a support material with high-surface area were synthesized using one-pot hydrothermal procedure with a surfactant such as cetyltrimethylammonium bromide (CTAB) as a template. Bi-metallic nanocatalysts of Pd-Ni and Pd-Co with varying metal loadings in MCM-41 were characterized by x-ray diffraction (XRD), N₂ adsorption, and Transmission electron microscopy (TEM) techniques. The BET surface area of MCM-41 (~1000 m²/g) containing metal nanoparticles decreases with the increase in metal loading. The FTIR studies confirm strong interaction between Si-O-M (M = Pd, Ni, Co) units and successful inclusion of metal into the mesoporous silica matrix. The catalyst activities were examined in steam reforming of methanol (SRM) reactions to produce hydrogen. Reference tests using catalysts containing individual metals (Pd, Ni and Co) were also performed to investigate the effect of the bimetallic system on the catalytic behavior in the SRM reactions. The bimetallic system remarkably improves the hydrogen selectivity, methanol conversion and stability of the catalyst. The results are consistent with a synergistic behavior for the Pd-Ni-bimetallic system. The performance, durability and thermal stability of the Pd-Ni/MCM-41 and Pd-Co/MCM-41 suggest that these materials may be promising catalysts for hydrogen production from biofuels. A part of this work for synthesis and characterization of Pd-Ni-MCM-41 and its activity for SRM reactions has been published (“Development of Mesoporous Silica Encapsulated Pd-Ni Nanocatalyst for Hydrogen Production” in “Production and Purification of Ultraclean

[Necessity of applying pharmacovigilance in post-marketing safety monitoring of traditional Chinese medicine injections].

Science.gov (United States)

Wang, Hai-Nan; Chen, Wen; Fu, Zheng; Du, Wen-min; He, Jia

2008-03-01

Traditional Chinese medicine (TCM) injection has become one of the hotspots in the new TCM research and development. The serious adverse drug reactions happened in clinical have arosed attention widely in the whole society. It's very urgent to monitor the post-marketing safety of TCM injections. This paper elucidated the pharmacovigilance's necessity in the post-marketing safety monitoring of TCM injections, basing on the reason of safety problem of TCM injections and the future developing trend of adverse drug reaction monitoring. Also, this paper introduced the rapid signal detection method of spontaneous reporting system database by data mining technology.

Response of a neutron monitor area with TLDs pairs

Energy Technology Data Exchange (ETDEWEB)

Guzman G, K. A.; Borja H, C. G.; Valero L, C.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Calle Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas (Mexico); Gallego, E.; Lorente, A., E-mail: ing_karen_guzman@yahoo.com.mx [Universidad Politecnica de Madrid, Departamento de Ingenieria Nuclear, Jose Gutierrez Abascal 2, E-28006 Madrid (Spain)

2011-10-15

The response of a passive neutron monitor area has been calculated using the Monte Carlo code MCNP5. The response was the amount of n({sup 6}Li, T){alpha} reactions occurring in a TLD-600 located at the center of a cylindrical polyethylene moderator. Fluence, (n, a) and H*(10) responses were calculated for 47 monoenergetic neutron sources. The H*(10) relative response was compared with responses of commercially available neutron monitors being alike. Due to {sup 6}Li cross section (n, {alpha}) reactions are mainly produced by thermal neutrons, however TLD-600 is sensitive to gamma-rays; to eliminate the signal due to photons monitor area was built to hold 2 pairs of TLD-600 and 2 pairs of TLD-700, thus from the difference between TLD-600 and TLD-700 readouts the net signal due to neutrons is obtained. The monitor area was calibrated at the Universidad Politecnica de Madrid using a {sup 241}AmBe neutron source; net TLD readout was compared with the H*(10) measured with a Bert hold Lb-6411. Performance of the neutron monitor area was determined through two independent experiments, in both cases the H*(10) was statistically equal to H*(10) measured with a Bert hold Lb-6411. Neutron monitor area with TLDs pairs can be used in working areas with intense, mixed and pulsed radiation fields. (Author)

Understanding and Improvement of an Experiment Measuring Chemical Reaction Rates by Monitoring Volume Change of a Gas: On the Reaction between HCl(aq) and Mg(s)

International Nuclear Information System (INIS)

Bang, Jeong Ah; Yoon, Hee Sook; Jeong, Dae Hong; Choi, Won Ho

2006-01-01

In this study we analyzed and improved an experiment measuring chemical reaction rates introduced in the high school science textbooks through an understanding of the phenomena observed in carrying out the experiment. For this purpose, the contents of textbooks related to the experiment were analyzed, and the problems observed in carrying out the experiment were addressed through experimental analysis. When the experiment was carried out by the method of aquatic transposition presented in textbooks, the observed volume change of H 2 gas was delayed and chemical reaction rate was increased in the early stage of reaction period. To resolve these problems, an improved method for measuring the reaction rates was suggested. In the improved experiment the reaction rate was measured to be constant on time, which was interpreted in terms of the concentration of H + and the surface area of magnesium

Penetrometer compatible, fiber-optic sensor for continuous monitoring of chlorinated hydrocarbons -- field test results

International Nuclear Information System (INIS)

Milanovich, F.P.; Brown, S.B.; Colston, B.W. Jr.

1993-04-01

We have developed and field tested a fiber optic chemical sensor for use in environmental monitoring and remediation. The principle of detection is colorimetric and is based on an irreversible chemical reaction between a specific reagent and the target compound. The formation of reaction products are monitored remotely with optical fibers. Successive or on-demand measurements are made possible with a reagent reservoir and a miniature pumping system. The sensor has been evaluated against gas chromatography standards and has demonstrated accuracy and sensitivity (>5ppb w/w) sufficient for the environmental monitoring of the contaminants triceoroethlyene (TCE) and chloroform. The sensor system can be used for bench-top analyses or for in-situ measurements such as groundwater and vadose monitoring wells or in Penetrometry mediated placements

Reaction monitoring using hyperpolarized NMR with scaling of heteronuclear couplings by optimal tracking

Science.gov (United States)

Zhang, Guannan; Schilling, Franz; Glaser, Steffen J.; Hilty, Christian

2016-11-01

Off-resonance decoupling using the method of Scaling of Heteronuclear Couplings by Optimal Tracking (SHOT) enables determination of heteronuclear correlations of chemical shifts in single scan NMR spectra. Through modulation of J-coupling evolution by shaped radio frequency pulses, off resonance decoupling using SHOT pulses causes a user-defined dependence of the observed J-splitting, such as the splitting of 13C peaks, on the chemical shift offset of coupled nuclei, such as 1H. Because a decoupling experiment requires only a single scan, this method is suitable for characterizing on-going chemical reactions using hyperpolarization by dissolution dynamic nuclear polarization (D-DNP). We demonstrate the calculation of [13C, 1H] chemical shift correlations of the carbanionic active sites from hyperpolarized styrene polymerized using sodium naphthalene as an initiator. While off resonance decoupling by SHOT pulses does not enhance the resolution in the same way as a 2D NMR spectrum would, the ability to obtain the correlations in single scans makes this method ideal for determination of chemical shifts in on-going reactions on the second time scale. In addition, we present a novel SHOT pulse that allows to scale J-splittings 50% larger than the respective J-coupling constant. This feature can be used to enhance the resolution of the indirectly detected chemical shift and reduce peak overlap, as demonstrated in a model reaction between p-anisaldehyde and isobutylamine. For both pulses, the accuracy is evaluated under changing signal-to-noise ratios (SNR) of the peaks from reactants and reaction products, with an overall standard deviation of chemical shift differences compared to reference spectra of 0.02 ppm when measured on a 400 MHz NMR spectrometer. Notably, the appearance of decoupling side-bands, which scale with peak intensity, appears to be of secondary importance.

Information about adverse drug reactions reported in children

DEFF Research Database (Denmark)

Aagaard, Lise; Christensen, Arne; Hansen, Ebba Holme

2010-01-01

AIM: To review the literature on adverse drug reactions (ADRs) in children with respect to occurrence, seriousness, type, therapeutic group, age and gender of the child and category of reporter. METHODS: Medline and Embase databases were searched from origin and updated until February 2010. We...... included empirically based articles on ADRs in populations aged 0 to 17 years. Studies monitoring ADRs in patients with particular conditions or drug exposure were excluded. We extracted information about types and seriousness of ADRs, therapeutic groups, age and gender of the child and category...... of reporter. ADR occurrence was calculated as incidence rate and prevalence. RESULTS: We included 33 studies monitoring ADRs in general paediatric populations. The highest numbers of ADRs were reported in national ADR databases where data were collected over a longer period than in studies monitoring...

FAST GC-FID METHOD FOR MONITORING ACIDIC AND BASIC CATALYTIC TRANSESTERIFICATION REACTIONS IN VEGETABLE OILS TO METHYL ESTER BIODIESEL PREPARATION

Directory of Open Access Journals (Sweden)

Renata Takabayashi Sato

2016-04-01

Full Text Available A fast gas chromatography with a flame ionisation detector (GC-FID method for the simultaneous analysis of methyl palmitate (C16:0, stearate (C18:0, oleate (C18:1, linoleate (C18:2 and linolenate (C18:3 in biodiesel samples was proposed. The analysis was conducted in a customised ionic-liquid stationary-phase capillary, SLB-IL 111, with a length of 14 m, an internal diameter of 0.10 mm, a film thickness of 0.08 µm and operated isothermally at 160 °C using hydrogen as the carrier gas at a rate of 50 cm s-1 in run time about 3 min. Once methyl myristate (C14:0 is present lower than 0.5% m/m in real samples it was used as an internal standard. The method was successful applied to monitoring basic and acidic catalysis transesterification reactions of vegetable oils such as soybean, canola, corn, sunflower and those used in frying process.

Insights into the mechanisms on chemical reactions: reaction paths for chemical reactions

International Nuclear Information System (INIS)

Dunning, T.H. Jr.; Rosen, E.; Eades, R.A.

1987-01-01

We report reaction paths for two prototypical chemical reactions: Li + HF, an electron transfer reaction, and OH + H 2 , an abstraction reaction. In the first reaction we consider the connection between the energetic terms in the reaction path Hamiltonian and the electronic changes which occur upon reaction. In the second reaction we consider the treatment of vibrational effects in chemical reactions in the reaction path formalism. 30 refs., 9 figs

Verification of multimarkers for detection of early stage diabetic retinopathy using multiple reaction monitoring.

Science.gov (United States)

Kim, Kyunggon; Kim, Sang Jin; Han, Dohyun; Jin, Jonghwa; Yu, Jiyoung; Park, Kyong Soo; Yu, Hyeong Gon; Kim, Youngsoo

2013-03-01

Diabetic retinopathy (DR) is a complication of diabetes and 80% of diabetes mellitus (DM) patients whose DM duration is over 10 years can be expected to suffer with DR. The diagnosis of DR depends on an ophthalmological examination, and no molecular methods of screening DR status exist. Nonproliferative diabetic retinopathy (NPDR) is the early DR which is hard to be noticed in early NPDR, showing significant cause of adult blindness in type 2 diabetes patients. Protein biomarkers have been valuable in the diagnosis of disease and the use of multiple biomarkers has been suggested to overcome the low specificity of single ones. For biomarker development, multiple reaction monitoring (MRM) has been spotlighted as an alternative method to quantify target proteins with no need for immunoassay. In this study, 54 candidate DR marker proteins from a previous study were verified by MRM in plasma samples from NPDR patients in 3 stages (mild, moderate and severe; 15 cases each) and diabetic patients without retinopathy (15 cases) as a control. Notably, 27 candidate markers distinguished moderate NPDR from type 2 diabetic patients with no diabetic retinopathy, generating AUC values (>0.7). Specifically, 28 candidate proteins underwent changes in expression as type 2 diabetic patients with no diabetic retinopathy progressed to mild and moderate NPDR. Further, a combination of 4 markers from these 28 candidates had the improved specificity in distinguishing moderate NPDR from type 2 diabetic patients with no diabetic retinopathy, yielding a merged AUC value of nearly 1.0. We concluded that MRM is a fast, robust approach of multimarker panel determination and an assay platform that provides improved specificity compared with single biomarker assay systems.

NBS activities in biological reference materials

Energy Technology Data Exchange (ETDEWEB)

Rasberry, S.D.

1988-12-01

NBS activities in biological reference materials during 1986-1988 are described with a preview of plans for future certifications of reference materials. During the period, work has been completed or partially completed on about 40 reference materials of importance to health, nutrition, and environmental quality. Some of the reference materials that have been completed during the period and are described include: creatinine (SRM 914a), bovine serum albumin (SRM 927a), cholesterol in human serum (SRM's 1951-1952), aspartate aminotransferase (RM 8430), cholesterol and fat-soluble vitamins in coconut oil (SRM 1563), wheat flour (SRM 1567a), rice flour (SRM 1568a), mixed diet (RM 8431a), dinitropyrene isomers and 1-nitropyrene (SRM 1596), and complex PAH's from coal tar (SRM 1597). Oyster tissue (SRM 1566a) is being analyzed and should be available in 1988.

Comparison of techniques for the determination of conversion during suspension polymerization reactions

Directory of Open Access Journals (Sweden)

J. C. Santos

2008-06-01

Full Text Available The determination of conversion during suspension polymerization reactions is not an easy task due to the heterogeneity of the reaction medium and the tendency of particles to agglomerate rapidly when stirring is stopped. Usually, bulk polymerization in ampoules is employed to study the kinetics of suspension polymerization reactions. In this work, a comparison of different techniques for the determination of conversion during suspension polymerization reactions is presented. Results showed a good agreement between the conversion obtained by gravimetry during styrene suspension polymerization and on-line conversion monitoring data using fiber-optic based Raman Spectroscopy. Nevertheless, the polymerization rate of styrene bulk polymerization carried out in ampoules was higher than the real reaction rate of styrene suspension polymerization due to slightly higher reaction temperatures. Simulation results using the experimental temperature data in a mathematical model confirmed these results.

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry for the determination of Cr, Fe, Cu, Zn and Se in cereals

Science.gov (United States)

Huang, Shih-Yi; Jiang, Shiuh-Jen; Sahayam, A. C.

2014-11-01

Ultrasonic slurry sampling electrothermal vaporization inductively coupled plasma mass spectrometry (USS-ETV-ICP-MS) has been applied to determine Cr, Fe, Cu, Zn and Se in several cereal samples. Thioacetamide was used as the modifier to enhance the ion signals. The background ions at the masses of interest were reduced in intensity significantly by using 1.0 mL min- 1 methane (CH4) as reaction cell gas in the dynamic reaction cell (DRC). Since the sensitivities of Cr, Fe, Cu, Zn and Se in different matrices were quite different, standard addition and isotope dilution methods were used for the determination of Cr, Fe, Cu, Zn and Se in these cereal samples. The method detection limits estimated from standard addition curves were about 1, 10, 4, 12 and 2 ng g- 1 for Cr, Fe, Cu, Zn and Se, respectively, in original cereal samples. This procedure has been applied to the determination of Cr, Fe, Cu, Zn and Se whose concentrations are in μg g- 1 (except Cr and Se) in standard reference materials (SRM) of National institute of standards and technology (NIST), NIST SRM 1568a Rice Flour and NIST SRM 1567a Wheat Flour and two cereal samples purchased from a local market. The analysis results of reference materials agreed with certified values at 95% confidence level according to Student's T-test. The results for the real world cereal samples were also found to be in good agreement with the pneumatic nebulization DRC ICP-MS results of the sample solutions.

Ambient Mechanochemical Solid-State Reactions of Carbon Nanotubes and Their Reactions via Covalent Coordinate Bond in Solution

Science.gov (United States)

Kabbani, Mohamad A.

In its first part, this thesis deals with ambient mechanochemical solid-state reactions of differently functionalized multiple walled carbon nanotubes (MWCNTs) while in its second part it investigates the cross-linking reactions of CNTs in solution via covalent coordinate bonds with transitions metals and carboxylate groups decorating their surfaces. In the first part a series of mechanochemical reactions involving different reactive functionalities on the CNTs such as COOH/OH, COOH/NH2 and COCl/OH were performed. The solid-state unzipping of CNTs leading to graphene formation was confirmed using spectroscopic, thermal and electron microscopy techniques. The non-grapheme products were established using in-situ quadruple mass spectroscopy. The experimental results were confirmed by theoretical simulation calculations using the 'hot spots' protocol. The kinetics of the reaction between MWCNT-COOH and MWCNT-OH was monitored using variable temperature Raman spectroscopy. The low activation energy was discussed in terms of hydrogen bond mediated proton transfer mechanism. The second part involves the reaction of MWCNTII COOH with Zn (II) and Cu (II) to form CNT metal-organic frame (MOFs) products that were tested for their effective use as counter-electrodes in dyes sensitized solar cells (DSSC). The thesis concludes by the study of the room temperature reaction between the functionalized graphenes, GOH and G'-COOH followed by the application of compressive loads. The 3D solid graphene pellet product ( 0.6gm/cc) is conductive and reflective with a 35MPa ultimate strength as compared to 10MPa strength of graphite electrode ( 2.2gm/cc).

Monitoring the wild black bear's reaction to human and environmental stressors

Directory of Open Access Journals (Sweden)

Iaizzo Paul A

2011-08-01

Full Text Available Abstract Background Bears are among the most physiologically remarkable mammals. They spend half their life in an active state and the other half in a state of dormancy without food or water, and without urinating, defecating, or physical activity, yet can rouse and defend themselves when disturbed. Although important data have been obtained in both captive and wild bears, long-term physiological monitoring of bears has not been possible until the recent advancement of implantable devices. Results Insertable cardiac monitors that were developed for use in human heart patients (Reveal® XT, Medtronic, Inc were implanted in 15 hibernating bears. Data were recovered from 8, including 2 that were legally shot by hunters. Devices recorded low heart rates (pauses of over 14 seconds and low respiration rates (1.5 breaths/min during hibernation, dramatic respiratory sinus arrhythmias in the fall and winter months, and elevated heart rates in summer (up to 214 beats/min (bpm and during interactions with hunters (exceeding 250 bpm. The devices documented the first and last day of denning, a period of quiescence in two parturient females after birthing, and extraordinary variation in the amount of activity/day, ranging from 0 (winter to 1084 minutes (summer. Data showed a transition toward greater nocturnal activity in the fall, preceding hibernation. The data-loggers also provided evidence of the physiological and behavioral responses of bears to our den visits to retrieve the data. Conclusions Annual variations in heart rate and activity have been documented for the first time in wild black bears. This technique has broad applications to wildlife management and physiological research, enabling the impact of environmental stressors from humans, changing seasons, climate change, social interactions and predation to be directly monitored over multiple years.

Chemical reactions on platinum-group metal surfaces studied by synchrotron-radiation-based spectroscopy

International Nuclear Information System (INIS)

Kondoh, Hiroshi; Nakai, Ikuyo; Nagasaka, Masanari; Amemiya, Kenta; Ohta, Toshiaki

2009-01-01

A new version of synchrotron-radiation-based x-ray spectroscopy, wave-length-dispersive near-edge x-ray absorption fine structure (dispersive-NEXAFS), and fast x-ray photoelectron spectroscopy have been applied to mechanistic studies on several surface catalytic reactions on platinum-group-metal surfaces. In this review, our approach using above techniques to understand the reaction mechanism and actual application studies on three well-known catalytic surface reactions, CO oxidation on Pt(111) and Pd(111), NO reduction on Rh(111), and H 2 O formation on Pt(111), are introduced. Spectroscopic monitoring of the progress of the surface reactions enabled us to detect reaction intermediates and analyze the reaction kinetics quantitatively which provides information on reaction order, rate constant, pre-exponential factor, activation energy and etc. Such quantitative analyses combined with scanning tunneling microscopy and kinetic Monte Carlo simulations revealed significant contribution of the adsorbate configurations and their dynamic changes to the reaction mechanisms of the above fundamental catalytic surface reactions. (author)

Illumination of Nanoliter-NMR Spectroscopy Chips for Real-Time Photochemical Reaction Monitoring

NARCIS (Netherlands)

Gomez, M.V.; Juan, Alberto; Jiménez-Márquez, Francisco; La Hoz, De Antonio; Velders, Aldrik H.

2018-01-01

We report the use of a small-volume nuclear-magnetic-resonance (NMR)-spectroscopy device with integrated fiber-optics for the real-time detection of UV-vis-light-assisted chemical reactions. An optical fiber is used to guide the light from LEDs or a laser diode positioned safely outside the magnet

Investigating radical cation chain processes in the electrocatalytic Diels-Alder reaction.

Science.gov (United States)

Imada, Yasushi; Okada, Yohei; Chiba, Kazuhiro

2018-01-01

Single electron transfer (SET)-triggered radical ion-based reactions have proven to be powerful options in synthetic organic chemistry. Although unique chain processes have been proposed in various photo- and electrochemical radical ion-based transformations, the turnover number, also referred to as catalytic efficiency, remains unclear in most cases. Herein, we disclose our investigations of radical cation chain processes in the electrocatalytic Diels-Alder reaction, leading to a scalable synthesis. A gram-scale synthesis was achieved with high current efficiency of up to 8000%. The reaction monitoring profiles showed sigmoidal curves with induction periods, suggesting the involvement of intermediate(s) in the rate determining step.

Monitorizing nitinol alloy surface reactions for biofouling studies

International Nuclear Information System (INIS)

Dinu, C.Z.; Dinca, V.C.; Soare, S.; Moldovan, A.; Smarandache, D.; Scarisoareanu, N.; Barbalat, A.; Birjega, R.; Dinescu, M.; DiStefano, V. Ferrari

2007-01-01

Growth and deposition of unwanted bacteria on implant metal alloys affect their use as biomedical samples. Monitoring any bacterial biofilm accumulation will provide early countermeasures. For a reliable antifouling strategy we prepared nitinol (NiTi) thin films on Ti-derived substrates by using a pulsed laser deposition (PLD) method. As the microstructure of Ti-alloy is dictated by the tensile strength, fatigue and the fracture toughness we tested the use of hydrogen as an alloying element. X-ray diffraction (XRD), scanning electron microscopy (SEM) and atomic force microscopy (AFM) investigated the crystalline structure, chemical composition and respectively the surface morphology of the nitinol hydrogen and hydrogen-free samples. Moreover, the alloys were integrated and tested using a cellular metric and their responses were systematic evaluated and quantified. Our attractive approach is meant to select the suitable components for an effective and trustworthy anti-fouling strategy. A greater understanding of such processes should lead to novel and effective control methods that would improve in the future implant stability and capabilities

Highly Reproducible Automated Proteomics Sample Preparation Workflow for Quantitative Mass Spectrometry.

Science.gov (United States)

Fu, Qin; Kowalski, Michael P; Mastali, Mitra; Parker, Sarah J; Sobhani, Kimia; van den Broek, Irene; Hunter, Christie L; Van Eyk, Jennifer E

2018-01-05

Sample preparation for protein quantification by mass spectrometry requires multiple processing steps including denaturation, reduction, alkylation, protease digestion, and peptide cleanup. Scaling these procedures for the analysis of numerous complex biological samples can be tedious and time-consuming, as there are many liquid transfer steps and timed reactions where technical variations can be introduced and propagated. We established an automated sample preparation workflow with a total processing time for 96 samples of 5 h, including a 2 h incubation with trypsin. Peptide cleanup is accomplished by online diversion during the LC/MS/MS analysis. In a selected reaction monitoring (SRM) assay targeting 6 plasma biomarkers and spiked β-galactosidase, mean intraday and interday cyclic voltammograms (CVs) for 5 serum and 5 plasma samples over 5 days were samples repeated on 3 separate days had total CVs below 20%. Similar results were obtained when the workflow was transferred to a second site: 93% of peptides had CVs below 20%. An automated trypsin digestion workflow yields uniformly processed samples in less than 5 h. Reproducible quantification of peptides was observed across replicates, days, instruments, and laboratory sites, demonstrating the broad applicability of this approach.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation.

Science.gov (United States)

Capel, Andrew J; Wright, Andrew; Harding, Matthew J; Weaver, George W; Li, Yuqi; Harris, Russell A; Edmondson, Steve; Goodridge, Ruth D; Christie, Steven D R

2017-01-01

Additive manufacturing or '3D printing' is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

Directory of Open Access Journals (Sweden)

Andrew J. Capel

2017-01-01

Full Text Available Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis.

3D printed fluidics with embedded analytic functionality for automated reaction optimisation

Science.gov (United States)

Capel, Andrew J; Wright, Andrew; Harding, Matthew J; Weaver, George W; Li, Yuqi; Harris, Russell A; Edmondson, Steve; Goodridge, Ruth D

2017-01-01

Additive manufacturing or ‘3D printing’ is being developed as a novel manufacturing process for the production of bespoke micro- and milliscale fluidic devices. When coupled with online monitoring and optimisation software, this offers an advanced, customised method for performing automated chemical synthesis. This paper reports the use of two additive manufacturing processes, stereolithography and selective laser melting, to create multifunctional fluidic devices with embedded reaction monitoring capability. The selectively laser melted parts are the first published examples of multifunctional 3D printed metal fluidic devices. These devices allow high temperature and pressure chemistry to be performed in solvent systems destructive to the majority of devices manufactured via stereolithography, polymer jetting and fused deposition modelling processes previously utilised for this application. These devices were integrated with commercially available flow chemistry, chromatographic and spectroscopic analysis equipment, allowing automated online and inline optimisation of the reaction medium. This set-up allowed the optimisation of two reactions, a ketone functional group interconversion and a fused polycyclic heterocycle formation, via spectroscopic and chromatographic analysis. PMID:28228852

Measurement of Walking Ground Reactions in Real-Life Environments: A Systematic Review of Techniques and Technologies.

Science.gov (United States)

Shahabpoor, Erfan; Pavic, Aleksandar

2017-09-12

Monitoring natural human gait in real-life environments is essential in many applications, including quantification of disease progression, monitoring the effects of treatment, and monitoring alteration of performance biomarkers in professional sports. Nevertheless, developing reliable and practical techniques and technologies necessary for continuous real-life monitoring of gait is still an open challenge. A systematic review of English-language articles from scientific databases including Scopus, ScienceDirect, Pubmed, IEEE Xplore, EBSCO and MEDLINE were carried out to analyse the 'accuracy' and 'practicality' of the current techniques and technologies for quantitative measurement of the tri-axial walking ground reactions outside the laboratory environment, and to highlight their strengths and shortcomings. In total, 679 relevant abstracts were identified, 54 full-text papers were included in the paper and the quantitative results of 17 papers were used for meta-analysis and comparison. Three classes of methods were reviewed: (1) methods based on measured kinematic data; (2) methods based on measured plantar pressure; and (3) methods based on direct measurement of ground reactions. It was found that all three classes of methods have competitive accuracy levels with methods based on direct measurement of the ground reactions showing highest accuracy while being least practical for long-term real-life measurement. On the other hand, methods that estimate ground reactions using measured body kinematics show highest practicality of the three classes of methods reviewed. Among the most prominent technical and technological challenges are: (1) reducing the size and price of tri-axial load-cells; (2) improving the accuracy of orientation measurement using IMUs; (3) minimizing the number and optimizing the location of required IMUs for kinematic measurement; (4) increasing the durability of pressure insole sensors, and (5) enhancing the robustness and versatility of the

Measurement of Walking Ground Reactions in Real-Life Environments: A Systematic Review of Techniques and Technologies

Directory of Open Access Journals (Sweden)

Erfan Shahabpoor

2017-09-01

Full Text Available Monitoring natural human gait in real-life environments is essential in many applications, including quantification of disease progression, monitoring the effects of treatment, and monitoring alteration of performance biomarkers in professional sports. Nevertheless, developing reliable and practical techniques and technologies necessary for continuous real-life monitoring of gait is still an open challenge. A systematic review of English-language articles from scientific databases including Scopus, ScienceDirect, Pubmed, IEEE Xplore, EBSCO and MEDLINE were carried out to analyse the ‘accuracy’ and ‘practicality’ of the current techniques and technologies for quantitative measurement of the tri-axial walking ground reactions outside the laboratory environment, and to highlight their strengths and shortcomings. In total, 679 relevant abstracts were identified, 54 full-text papers were included in the paper and the quantitative results of 17 papers were used for meta-analysis and comparison. Three classes of methods were reviewed: (1 methods based on measured kinematic data; (2 methods based on measured plantar pressure; and (3 methods based on direct measurement of ground reactions. It was found that all three classes of methods have competitive accuracy levels with methods based on direct measurement of the ground reactions showing highest accuracy while being least practical for long-term real-life measurement. On the other hand, methods that estimate ground reactions using measured body kinematics show highest practicality of the three classes of methods reviewed. Among the most prominent technical and technological challenges are: (1 reducing the size and price of tri-axial load-cells; (2 improving the accuracy of orientation measurement using IMUs; (3 minimizing the number and optimizing the location of required IMUs for kinematic measurement; (4 increasing the durability of pressure insole sensors, and (5 enhancing the robustness and

A sensitive mass spectrometric method for hypothesis-driven detection of peptide post-translational modifications: multiple reaction monitoring-initiated detection and sequencing (MIDAS).

Science.gov (United States)

Unwin, Richard D; Griffiths, John R; Whetton, Anthony D

2009-01-01

The application of a targeted mass spectrometric workflow to the sensitive identification of post-translational modifications is described. This protocol employs multiple reaction monitoring (MRM) to search for all putative peptides specifically modified in a target protein. Positive MRMs trigger an MS/MS experiment to confirm the nature and site of the modification. This approach, termed MIDAS (MRM-initiated detection and sequencing), is more sensitive than approaches using neutral loss scanning or precursor ion scanning methodologies, due to a more efficient use of duty cycle along with a decreased background signal associated with MRM. We describe the use of MIDAS for the identification of phosphorylation, with a typical experiment taking just a couple of hours from obtaining a peptide sample. With minor modifications, the MIDAS method can be applied to other protein modifications or unmodified peptides can be used as a MIDAS target.

Self-activated, self-limiting reactions on Si surfaces

DEFF Research Database (Denmark)

Morgen, Per; Hvam, Jeanette; Bahari, Ali

The direct thermally activated reactions of oxygen and ammonia with Si surfaces in furnaces have been used for a very long time in the semiconductor industry for the growth of thick oxides and nitride layers respectively. The oxidation mechanism was described in the Deal-Grove model as a diffusion...... mechanism for the direct growth of ultrathin films (0-3 nm) of oxides and nitrides under ultrahigh vacuum conditions. Neutral oxygen and a microwave excited nitrogen plasma interact directly with Si surfaces kept at different temperatures during the reaction. The gas pressures are around 10-6 Torr...... energy of an oxide system, which happened for an ordered structure, at a thickness of 0.7-0.8 nm. Thus this thin oxide structure has definite crystalline features. We have closely monitored the reaction kinetics with normal x-ray induced photoelectron spectroscopies, and also the structure, composition...

Determination of Iodate in Food, Environmental, and Biological Samples after Solid-Phase Extraction with Ni-Al-Zr Ternary Layered Double Hydroxide as a Nanosorbent

Directory of Open Access Journals (Sweden)

Hossein Abdolmohammad-Zadeh

2012-01-01

Full Text Available Nanostructured nickel-aluminum-zirconium ternary layered double hydroxide was successfully applied as a solid-phase extraction sorbent for the separation and pre-concentration of trace levels of iodate in food, environmental and biological samples. An indirect method was used for monitoring of the extracted iodate ions. The method is based on the reaction of the iodate with iodide in acidic solution to produce iodine, which can be spectrophotometrically monitored at 352 nm. The absorbance is directly proportional to the concentration of iodate in the sample. The effect of several parameters such as pH, sample flow rate, amount of nanosorbent, elution conditions, sample volume, and coexisting ions on the recovery was investigated. In the optimum experimental conditions, the limit of detection (3s and enrichment factor were 0.12 μg mL−1 and 20, respectively. The calibration graph using the preconcentration system was linear in the range of 0.2–2.8 μg mL−1 with a correlation coefficient of 0.998. In order to validate the presented method, a certified reference material, NIST SRM 1549, was also analyzed.

Improving OCD time to solution using Signal Response Metrology

Science.gov (United States)

Fang, Fang; Zhang, Xiaoxiao; Vaid, Alok; Pandev, Stilian; Sanko, Dimitry; Ramanathan, Vidya; Venkataraman, Kartik; Haupt, Ronny

2016-03-01

In recent technology nodes, advanced process and novel integration scheme have challenged the precision limits of conventional metrology; with critical dimensions (CD) of device reduce to sub-nanometer region. Optical metrology has proved its capability to precisely detect intricate details on the complex structures, however, conventional RCWA-based (rigorous coupled wave analysis) scatterometry has the limitations of long time-to-results and lack of flexibility to adapt to wide process variations. Signal Response Metrology (SRM) is a new metrology technique targeted to alleviate the consumption of engineering and computation resources by eliminating geometric/dispersion modeling and spectral simulation from the workflow. This is achieved by directly correlating the spectra acquired from a set of wafers with known process variations encoded. In SPIE 2015, we presented the results of SRM application in lithography metrology and control [1], accomplished the mission of setting up a new measurement recipe of focus/dose monitoring in hours. This work will demonstrate our recent field exploration of SRM implementation in 20nm technology and beyond, including focus metrology for scanner control; post etch geometric profile measurement, and actual device profile metrology.

Chemical research on red pigments after adverse reactions to tattoo.

Science.gov (United States)

Tammaro, A; Toniolo, C; Giulianelli, V; Serafini, M; Persechino, S

2016-03-01

Currently, the incidence of tattooing is on the rise compared to the past, especially among adolescents, and it leads to the urgency of monitoring the security status of tattooing centers, as well as to inform people about the risks of tattoo practice. In our clinical experience, 20% of tattooed patients presented adverse reactions, like allergic contact dermatitis, psoriasis with Koebner's phenomena and granulomatous reactions, with the latter most prevalent and most often related to red pigment. Adverse reactions to tattoo pigments, especially the red one, are well known and described in literature. Great attention has to be focused on the pigments used, especially for the presence of new substances, often not well known. For this reason, we decided to perform a study on 12 samples of red tattoo ink, obtained by patients affected by different cutaneous reactions in the site of tattoo, to analyze their chemical composition.

Enzyme-catalyzed and binding reaction kinetics determined by titration calorimetry.

Science.gov (United States)

Hansen, Lee D; Transtrum, Mark K; Quinn, Colette; Demarse, Neil

2016-05-01

Isothermal calorimetry allows monitoring of reaction rates via direct measurement of the rate of heat produced by the reaction. Calorimetry is one of very few techniques that can be used to measure rates without taking a derivative of the primary data. Because heat is a universal indicator of chemical reactions, calorimetry can be used to measure kinetics in opaque solutions, suspensions, and multiple phase systems and does not require chemical labeling. The only significant limitation of calorimetry for kinetic measurements is that the time constant of the reaction must be greater than the time constant of the calorimeter which can range from a few seconds to a few minutes. Calorimetry has the unique ability to provide both kinetic and thermodynamic data. This article describes the calorimetric methodology for determining reaction kinetics and reviews examples from recent literature that demonstrate applications of titration calorimetry to determine kinetics of enzyme-catalyzed and ligand binding reactions. A complete model for the temperature dependence of enzyme activity is presented. A previous method commonly used for blank corrections in determinations of equilibrium constants and enthalpy changes for binding reactions is shown to be subject to significant systematic error. Methods for determination of the kinetics of enzyme-catalyzed reactions and for simultaneous determination of thermodynamics and kinetics of ligand binding reactions are reviewed. Copyright © 2015 Elsevier B.V. All rights reserved.

Supplemental figure: Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions at $\\mathbf{\\sqrt{{\\textit s}_{\\rm NN}}}$ = 2.76 TeV

CERN Document Server

2015-01-01

This note provides a supplemental figure for data on ``Anisotropic flow of charged hadrons, pions and (anti-)protons measured at high transverse momentum in Pb-Pb collisions $\\mathbf{\\sqrt{{\\textit s}_{\\rm NN}}}$ = 2.76~TeV" published in \\href{http://www.sciencedirect.com/science/article/pii/S037026931300004X}{Phys.\\ Lett.\\ B {\\bf 719}, 18 (2013)}, \\href{http://arxiv.org/abs/1205.5761}{arXiv:1205.5761}. The figure~(\\ref{fig:v2_pid}) presents the $v_2$ of charged pions and protons (particles and anti-particles are not distinguished in this analysis) from the event plane method as a function of transverse momentum for different centrality classes as reported in Fig. 5 of the \\href{http://www.sciencedirect.com/science/article/pii/S037026931300004X}{publication}. The proton $v_2$ is higher than that of pions out to $\\pt=8$~GeV/$c$ where the uncertainties become large.

Self-regulation method: psychological, physiological and clinical considerations. An overview.

Science.gov (United States)

Ikemi, A; Tomita, S; Kuroda, M; Hayashida, Y; Ikemi, Y

1986-01-01

Body-oriented therapies as relaxation training and certain forms of meditation are gaining popularity in the treatment and prevention of psychosomatic disorders. In this paper, a new method of self-control called self-regulation method (SRM), derived from autogenic training and Zen meditation, is presented. The technique of SRM is introduced. Secondly, physiological studies on SRM using skin temperature, galvanic skin response, and cortical evoked potentials are presented. Thirdly, the results of psychological tests conducted on SRM are presented. These psycho-physiological studies suggest that SRM may elicit a state of 'relaxed alertness'. Fourthly, clinical applications of SRM are discussed, and 3 cases are presented. Finally, SRM is discussed in relation to the psychology and physiology of 'relaxed alertness'.

LC-MS/MS Detection of Karlotoxins Reveals New Variants in Strains of the Marine Dinoflagellate Karlodinium veneficum from the Ebro Delta (NW Mediterranean

Directory of Open Access Journals (Sweden)

Bernd Krock

2017-12-01

Full Text Available A liquid chromatography-tandem mass spectrometry (LC-MS/MS method was developed for the detection and quantitation of karlotoxins in the selected reaction monitoring (SRM mode. This novel method was based upon the analysis of purified karlotoxins (KcTx-1, KmTx-2, 44-oxo-KmTx-2, KmTx-5, one amphidinol (AM-18, and unpurified extracts of bulk cultures of the marine dinoflagellate Karlodinium veneficum strain CCMP2936 from Delaware (Eastern USA, which produces KmTx-1 and KmTx-3. The limit of detection of the SRM method for KmTx-2 was determined as 2.5 ng on-column. Collision induced dissociation (CID spectra of all putative karlotoxins were recorded to present fragmentation patterns of each compound for their unambiguous identification. Bulk cultures of K. veneficum strain K10 isolated from an embayment of the Ebro Delta, NW Mediterranean, yielded five previously unreported putative karlotoxins with molecular masses 1280, 1298, 1332, 1356, and 1400 Da, and similar fragments to KmTx-5. Analysis of several isolates of K. veneficum from the Ebro Delta revealed small-scale diversity in the karlotoxin spectrum in that one isolate from Fangar Bay produced KmTx-5, whereas the five putative novel karlotoxins were found among several isolates from nearby, but hydrographically distinct Alfacs Bay. Application of this LC-MS/MS method represents an incremental advance in the determination of putative karlotoxins, particularly in the absence of a complete spectrum of purified analytical standards of known specific potency.

Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

Energy Technology Data Exchange (ETDEWEB)

Aguiar, Pablo, E-mail: pablo.aguiar.fernandez@sergas.es [Fundación Ramón Domínguez, Medicina Nuclear, CHUS, Spain and Grupo de Imaxe Molecular, IDIS, Santiago de Compostela 15706 (Spain); Pino, Francisco [Unitat de Biofísica, Facultat de Medicina, Universitat de Barcelona, Spain and Servei de Física Médica i Protecció Radiológica, Institut Catalá d' Oncologia, Barcelona 08036 (Spain); Silva-Rodríguez, Jesús [Fundación Ramón Domínguez, Medicina Nuclear, CHUS, Santiago de Compostela 15706 (Spain); Pavía, Javier [Servei de Medicina Nuclear, Hospital Clínic, Barcelona (Spain); Institut d' Investigacions Biomèdiques August Pí i Sunyer (IDIBAPS) (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Ros, Doménec [Unitat de Biofísica, Facultat de Medicina, Casanova 143 (Spain); Institut d' Investigacions Biomèdiques August Pí i Sunyer (IDIBAPS) (Spain); CIBER en Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN), Barcelona 08036 (Spain); Ruibal, Álvaro [Servicio Medicina Nuclear, CHUS (Spain); Grupo de Imaxe Molecular, Facultade de Medicina (USC), IDIS, Santiago de Compostela 15706 (Spain); Fundación Tejerina, Madrid (Spain); and others

2014-03-15

Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

Analytical, experimental, and Monte Carlo system response matrix for pinhole SPECT reconstruction

International Nuclear Information System (INIS)

Aguiar, Pablo; Pino, Francisco; Silva-Rodríguez, Jesús; Pavía, Javier; Ros, Doménec; Ruibal, Álvaro

2014-01-01

Purpose: To assess the performance of two approaches to the system response matrix (SRM) calculation in pinhole single photon emission computed tomography (SPECT) reconstruction. Methods: Evaluation was performed using experimental data from a low magnification pinhole SPECT system that consisted of a rotating flat detector with a monolithic scintillator crystal. The SRM was computed following two approaches, which were based on Monte Carlo simulations (MC-SRM) and analytical techniques in combination with an experimental characterization (AE-SRM). The spatial response of the system, obtained by using the two approaches, was compared with experimental data. The effect of the MC-SRM and AE-SRM approaches on the reconstructed image was assessed in terms of image contrast, signal-to-noise ratio, image quality, and spatial resolution. To this end, acquisitions were carried out using a hot cylinder phantom (consisting of five fillable rods with diameters of 5, 4, 3, 2, and 1 mm and a uniform cylindrical chamber) and a custom-made Derenzo phantom, with center-to-center distances between adjacent rods of 1.5, 2.0, and 3.0 mm. Results: Good agreement was found for the spatial response of the system between measured data and results derived from MC-SRM and AE-SRM. Only minor differences for point sources at distances smaller than the radius of rotation and large incidence angles were found. Assessment of the effect on the reconstructed image showed a similar contrast for both approaches, with values higher than 0.9 for rod diameters greater than 1 mm and higher than 0.8 for rod diameter of 1 mm. The comparison in terms of image quality showed that all rods in the different sections of a custom-made Derenzo phantom could be distinguished. The spatial resolution (FWHM) was 0.7 mm at iteration 100 using both approaches. The SNR was lower for reconstructed images using MC-SRM than for those reconstructed using AE-SRM, indicating that AE-SRM deals better with the

High resolution studies of the effects of magnetic fields on chemical reactions

OpenAIRE

Hamilton, C. A.; Hewitt, J. P.; McLauchlan, Keith A.; Steiner, Ulrich

1988-01-01

A simple and inexpensive experiment is described which detects magnetic field effects on chemical reactions with high signal-to-noise ratio and high resolution. It consists in applying a small modulation field to the sample, whilst the main field it experiences is varied, with optical detection at the modulation frequency. It consequently measures the derivative of the normal MARY spectrum. It is shown by theoretical analysis that when using this method it is better to monitor reaction interm...

Reaction sintering of a clay-containing silicon nitride bonded silicon carbide refractory

International Nuclear Information System (INIS)

Swenser, S.P.; Cheng, Y.B.

1998-01-01

Aspects of the reaction sequence for the reaction bonding of a cast refractory, which in the green state was composed of 79 wt-% SiC grit, 16 wt-% Si powder and 5 wt-% clay were established. As it was fired up to 1600 deg C in flowing N 2 (g), weight gains were noted and phase evolution was monitored by X-ray diffraction. However, details of the reaction sequence were not determined directly from this material because several reaction-bonding processes occurred simultaneously. Reaction features were ascertained by contrasting the weight changes and phase evolution in the refractory with those observed during reaction-bonding of (a) Si and clay without the SiC and (b) SiC and clay without the Si. In addition to silicon nitridation and the development of sialon phases by silicothermal and carbothermal reduction-nitridation processes, indirect evidence suggested that α-Si 3 N 4 formed by the carbothermal reduction-nitridation (CRN) of SiO(g). Copyright (1998) Australasian Ceramic Society

Portable formaldehyde monitoring device using porous glass sensor and its applications in indoor air quality studies.

Science.gov (United States)

Maruo, Yasuko Yamada; Nakamura, Jiro

2011-09-30

We have developed a portable device for formaldehyde monitoring with both high sensitivity and high temporal resolution, and carried out indoor air formaldehyde concentration analysis. The absorbance difference of the sensor element was measured in the monitoring device at regular intervals of, for example, one hour or 30 min, and the result was converted into the formaldehyde concentration. This was possible because we found that the lutidine derivative that was formed as a yellow product of the reaction between 1-phenyl-1,3-butandione and formaldehyde was stable in porous glass for at least six months. We estimated the reaction rate and to be 0.049 min(-1) and the reaction occurred quickly enough for us to monitor hourly changes in the formaldehyde concentration. The detection limit was 5 μg m(-3) h. We achieved hourly formaldehyde monitoring using the developed device under several indoor conditions, and estimated the air exchange rate and formaldehyde adsorption rate, which we adopted as a new term in the mass balance equation for formaldehyde, in one office. Copyright © 2011 Elsevier B.V. All rights reserved.

Quantitative analysis of glycosaminoglycans, chondroitin/dermatan sulfate, hyaluronic acid, heparan sulfate, and keratan sulfate by liquid chromatography-electrospray ionization-tandem mass spectrometry.

Science.gov (United States)

Osago, Harumi; Shibata, Tomoko; Hara, Nobumasa; Kuwata, Suguru; Kono, Michihaya; Uchio, Yuji; Tsuchiya, Mikako

2014-12-15

We developed a method using liquid chromatography-electrospray ionization-tandem mass spectrometry (LC-ESI-MS/MS) with a selected reaction monitoring (SRM) mode for simultaneous quantitative analysis of glycosaminoglycans (GAGs). Using one-shot analysis with our MS/MS method, we demonstrated the simultaneous quantification of a total of 23 variously sulfated disaccharides of four GAG classes (8 chondroitin/dermatan sulfates, 1 hyaluronic acid, 12 heparan sulfates, and 2 keratan sulfates) with a sensitivity of less than 0.5 pmol within 20 min. We showed the differences in the composition of GAG classes and the sulfation patterns between porcine articular cartilage and yellow ligament. In addition to the internal disaccharides described above, some saccharides derived from the nonreducing terminal were detected simultaneously. The simultaneous quantification of both internal and nonreducing terminal saccharides could be useful to estimate the chain length of GAGs. This method would help to establish comprehensive "GAGomic" analysis of biological tissues. Copyright © 2014 Elsevier Inc. All rights reserved.

Liquid chromatography-electrospray ionization tandem mass spectrometry and dynamic multiple reaction monitoring method for determining multiple pesticide residues in tomato.

Science.gov (United States)

Andrade, G C R M; Monteiro, S H; Francisco, J G; Figueiredo, L A; Botelho, R G; Tornisielo, V L

2015-05-15

A quick and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry method, using dynamic multiple reaction monitoring and a 1.8-μm particle size analytical column, was developed to determine 57 pesticides in tomato in a 13-min run. QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for samples preparations and validations was carried out in compliance with EU SANCO guidelines. The method was applied to 58 tomato samples. More than 84% of the compounds investigated showed limits of detection equal to or lower than 5 mg kg(-1). A mild (50%) matrix effect was observed for 72%, 25%, and 3% of the pesticides studied, respectively. Eighty-one percent of the pesticides showed recoveries ranging between 70% and 120%. Twelve pesticides were detected in 35 samples, all below the maximum residue levels permitted in the Brazilian legislation; 15 samples exceeded the maximum residue levels established by the EU legislation for methamidophos; and 10 exceeded limits for acephate and four for bromuconazole. Copyright © 2014 Elsevier Ltd. All rights reserved.

Rapid determination of alkaloids in Macleaya cordata using ionic liquid extraction followed by multiple reaction monitoring UPLC-MS/MS analysis.

Science.gov (United States)

Li, Linqiu; Huang, Mingyuan; Shao, Junli; Lin, Bokun; Shen, Qing

2017-02-20

The ultrasonic-assisted extraction (UAE) and ionic liquid based dispersive liquid-liquid microextraction (IL-DLLME) have been successfully applied in extracting of six alkaloids from M. cordata. 1-hexyl-3-methylimidazolium tetrafluoroborate ([C 6 MIM][BF 4 ]) aqueous solution was used as extraction solvent. The target analytes in raw material were deposited into a single drop of 1-hexyl-3-methylimidazolium hexafluorophosphate ([C 6 MIM][PF 6 ]), which was in situ formed by mixing [C 6 MIM][BF 4 ] and potassium hexafluorophosphate ([K][PF 6 ]. Afterwards, the extract was analyzed by ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) in multiple-reaction monitoring (MRM) mode. The proposed method was fully validated in terms of linearity (0.9983-0.9992), LOD (0.080ngmL -1 ), LOQ (0.25ngmL -1 ), intra-day precision (MS/MS is powerful and practical for analyzing alkaloids in M. cordata., and it also has great potential for comprehensive quality control of other herbal medicines. Copyright © 2016 Elsevier B.V. All rights reserved.

Development of mediator-type biosensor to wirelessly monitor whole cholesterol concentration in fish.

Science.gov (United States)

Takase, Mai; Murata, Masataka; Hibi, Kyoko; Huifeng, Ren; Endo, Hideaki

2014-04-01

We developed a wireless monitoring system to monitor fish condition by tracking the change in whole cholesterol concentration. The whole cholesterol concentration of fish is a source of steroid hormones or indicator of immunity level, which makes its detection important for tracking physiological condition of fish. Wireless monitoring system comprises of mediator-type biosensor and wireless transmission device. Biosensor is implantable to fish body, and transmission device is so light, in that fish is allowed to swim freely during monitoring. Cholesterol esterase and oxidase were fixated on to the detection site of biosensor and used to detect the whole cholesterol concentration. However, cholesterol oxidase incorporates oxidation-reduction reaction of oxygen for detection, which concentration fluctuates easily due to change in environmental condition. Meanwhile, mediator-type biosensor enables monitoring of whole cholesterol concentration by using mediator to substitute that oxidation-reduction reaction of oxygen. Characteristic of fabricated mediator-type biosensor was tested. The sensor output current of mediator-type biosensor remained stable compared to output current of non-mediator-type biosensor under fluctuating oxygen concentration of 0-8 ppm, which implied that this sensor is less affected by change in dissolved oxygen concentration. That biosensor was then implanted into fish for wireless monitoring. As a result, approximately 48 h of real-time monitoring was successful.

Surface-Activated Coupling Reactions Confined on a Surface.

Science.gov (United States)

Dong, Lei; Liu, Pei Nian; Lin, Nian

2015-10-20

Chemical reactions may take place in a pure phase of gas or liquid or at the interface of two phases (gas-solid or liquid-solid). Recently, the emerging field of "surface-confined coupling reactions" has attracted intensive attention. In this process, reactants, intermediates, and products of a coupling reaction are adsorbed on a solid-vacuum or a solid-liquid interface. The solid surface restricts all reaction steps on the interface, in other words, the reaction takes place within a lower-dimensional, for example, two-dimensional, space. Surface atoms that are fixed in the surface and adatoms that move on the surface often activate the surface-confined coupling reactions. The synergy of surface morphology and activity allow some reactions that are inefficient or prohibited in the gas or liquid phase to proceed efficiently when the reactions are confined on a surface. Over the past decade, dozens of well-known "textbook" coupling reactions have been shown to proceed as surface-confined coupling reactions. In most cases, the surface-confined coupling reactions were discovered by trial and error, and the reaction pathways are largely unknown. It is thus highly desirable to unravel the mechanisms, mechanisms of surface activation in particular, of the surface-confined coupling reactions. Because the reactions take place on surfaces, advanced surface science techniques can be applied to study the surface-confined coupling reactions. Among them, scanning tunneling microscopy (STM) and X-ray photoelectron spectroscopy (XPS) are the two most extensively used experimental tools. The former resolves submolecular structures of individual reactants, intermediates, and products in real space, while the latter monitors the chemical states during the reactions in real time. Combination of the two methods provides unprecedented spatial and temporal information on the reaction pathways. The experimental findings are complemented by theoretical modeling. In particular, density

Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

Science.gov (United States)

Krkošek, Wendy H; Koziar, Stephen A; White, Robert L; Gagnon, Graham A

2011-01-01

High global consumption rates have led to the occurrence of pharmaceutically active compounds (PhACs) in wastewater. The use of chlorine to disinfect wastewater prior to release into the environment may convert PhACs into uncharacterized chlorinated by-products. In this investigation, chlorination of a common pharmaceutical, the antihyperlipidemic agent gemfibrozil, was documented. Gemfibrozil (2,2-dimethyl-5-(2,5-dimethylphenoxy)pentanoic acid) was reacted with sodium hypochlorite and product formation was monitored by gas chromatography-mass spectrometry (GC-MS). The incorporation of one, two or three chlorine atoms into the aromatic region of gemfibrozil was demonstrated using negative-ion electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (ESI-MS/MS). Further analysis using (1)H nuclear magnetic resonance (NMR) spectroscopy identified the reaction products as 4'-ClGem (5-(4-chloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid) 4',6'-diClGem (5-(4,6-dichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), and 3',4',6'-triClGem (5-(3,4,6-trichloro-2,5-dimethylphenoxy)-2,2-dimethylpentanoic acid), products consistent with electrophilic aromatic substitution reactions. The rapid reaction of gemfibrozil with free chlorine at pH conditions relevant to water treatment indicates that a mixture of chlorinated gemfibrozils is likely to be found in wastewater disinfected with chlorine. Copyright © 2010 Elsevier Ltd. All rights reserved.

Sugarcane bagasse gasification: Global reaction mechanism of syngas evolution

International Nuclear Information System (INIS)

Ahmed, I.I.; Gupta, A.K.

2012-01-01

Highlights: ► Gasification of sugarcane bagasse has been investigated using a semi batch reactor. ► Global reaction mechanism combining pyrolysis and gasification reactions is presented. ► High flow rates of syngas supported fragmentation and secondary reactions. ► CO flow rate increased at higher heating rates at the expense of CO 2 production. ► At high temperatures merger between pyrolysis and char gasification occurs. -- Abstract: Steam gasification of sugarcane bagasse has been investigated. A semi batch reactor with a fixed amount of sugarcane bagasse sample placed in steady flow of high temperature steam at atmospheric pressure has been used. The gasification of bagasse was examined at reactor and steam temperatures of 800, 900 and 1000 °C. The evolution of syngas flow rate and chemical composition has been monitored. The evolution of chemical composition and total flow rate of the syngas has been used to formulate a global reaction mechanism. The mechanism combines pyrolysis reaction mechanisms from the literature and steam gasification/reforming reactions. Steam gasification steps include steam–hydrocarbons reforming, char gasification and water gas shift reactions. Evidence of fragmentation, secondary ring opening reactions and tertiary reactions resulting in formation of gaseous hydrocarbons is supported by higher flow rates of syngas and hydrogen at high heating rates and high reactor temperatures. Increase in carbon monoxide flow rate at the expense of carbon dioxide flow rate with the increase in reactor temperature has been observed. This increase in the ratio of CO/CO 2 flow rate confirms the production of CO and CO 2 from the competing reaction routes. At 1000 °C gasification a total merging between the pyrolysis step and the char gasification step has been observed. This is attributed to acceleration of char gasification reactions and acceleration of steam–hydrocarbons reforming reactions. These hydrocarbons are the precursors to

Sulfate metabolites as alternative markers for the detection of 4-chlorometandienone misuse in doping control.

Science.gov (United States)

Balcells, Georgina; Gómez, Cristina; Garrostas, Lorena; Pozo, Óscar J; Ventura, Rosa

2017-07-01

Sulfate metabolites have been described as long-term metabolites for some anabolic androgenic steroids (AAS). 4-chlorometandienone (4Cl-MTD) is one of the most frequently detected AAS in sports drug testing and it is commonly detected by monitoring metabolites excreted free or conjugated with glucuronic acid. Sulfation reactions of 4Cl-MTD have not been studied. The aim of this work was to evaluate the sulfate fraction of 4Cl-MTD metabolism by liquid chromatography-tandem mass spectrometry (LC-MS/MS) to establish potential long-term metabolites valuable for doping control purposes. 4Cl-MTD was administered to two healthy male volunteers and urine samples were collected up to 8 days after administration. A theoretical selected reaction monitoring (SRM) method working in negative mode was developed. Ion transitions were based on ionization and fragmentation behaviour of sulfate metabolites as well as specific neutral losses (NL of 15 Da and NL of 36 Da) of compounds with related chemical structure. Six sulfate metabolites were detected after the analysis of excretion study samples. Three of the identified metabolites were characterized by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-tandem mass spectrometry (GC-MS/MS). Results showed that five out of the six identified sulfate metabolites were detected in urine up to the last collected samples from both excretion studies. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

Time-resolved monitoring of enzyme activity with ultrafast Hyper-CEST spectroscopy.

Science.gov (United States)

Döpfert, Jörg; Schnurr, Matthias; Kunth, Martin; Rose, Honor May; Hennig, Andreas; Schröder, Leif

2017-12-23

We propose a method to dynamically monitor the progress of an enzymatic reaction using NMR of hyperpolarized 129 Xe in a host-guest system. It is based on a displacement assay originally designed for fluorescence experiments that exploits the competitive binding of the enzymatic product on the one hand and a reporter dye on the other hand to a supramolecular host. Recently, this assay has been successfully transferred to NMR, using xenon as a reporter, cucurbit[6]uril as supramolecular host, and chemical exchange saturation transfer with hyperpolarized Xe (Hyper-CEST) as detection technique. Its advantage is that the enzyme acts on the unmodified substrate and that only the product is detected through immediate inclusion into the host. We here apply a method that drastically accelerates the acquisition of Hyper-CEST spectra in vitro using magnetic field gradients. This allows monitoring the dynamic progress of the conversion of lysine to cadaverine with a temporal resolution of ~30 s. Moreover, the method only requires to sample the very early onset of the reaction (Hyper-CEST results correlate with xenon T 2 measurements performed during the enzymatic reaction. This suggests that ultrafast Hyper-CEST spectroscopy can be used for dynamically monitoring enzymatic activity with NMR. Copyright © 2017 John Wiley & Sons, Ltd.

Preferential processing of tactile events under conditions of divided attention: Effects of divided attention on reaction time

OpenAIRE

Hanson, James V. M.; Whitaker, David; Heron, James

2009-01-01

Differences in transduction and transmission latencies of visual, auditory and tactile events cause corresponding differences in simple reaction time. As reaction time is usually measured in unimodal blocks, it is unclear whether such latency differences also apply when observers monitor multiple sensory channels. We investigate this by comparing reaction time when attention is focussed on a single modality, and when attention is divided between multiple modalities. Results show that tactile ...

Biodiesel transesterification kinetics monitored by pH measurement.

Science.gov (United States)

Clark, William M; Medeiros, Nicholas J; Boyd, Donal J; Snell, Jared R

2013-05-01

Quantification of a pH change that was observed over the course of the transesterification reaction that converts vegetable oil to biodiesel may provide a simple method to monitor the reaction. Transesterification of canola oil at 6:1 methanol to oil ratio with 0.5 wt.% KOH as catalyst was studied at 25, 35, and 45 °C. Reaction conversion was correlated to pH measurements and the results were shown to be in agreement with an independent measure of conversion using an enzymatic assay for glycerol. Rate constants obtained from these measurements are consistent with those in the literature. The measured pH change appears to be related to dilution of OH(-) ions as the oil is converted to products rather than to depletion of OH(-) due to reaction. Copyright © 2013 Elsevier Ltd. All rights reserved.

Intact protein analysis of ubiquitin in cerebrospinal fluid by multiple reaction monitoring reveals differences in Alzheimer's disease and frontotemporal lobar degeneration.

Science.gov (United States)

Oeckl, Patrick; Steinacker, Petra; von Arnim, Christine A F; Straub, Sarah; Nagl, Magdalena; Feneberg, Emily; Weishaupt, Jochen H; Ludolph, Albert C; Otto, Markus

2014-11-07

The impairment of the ubiquitin-proteasome system (UPS) is thought to be an early event in neurodegeneration, and monitoring UPS alterations might serve as a disease biomarker. Our aim was to establish an alternate method to antibody-based assays for the selective measurement of free monoubiquitin in cerebrospinal fluid (CSF). Free monoubiquitin was measured with liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MS/MS) in CSF of patients with Alzheimer's disease (AD), amyotrophic lateral sclerosis (ALS), behavioral variant of frontotemporal dementia (bvFTD), Creutzfeldt-Jakob disease (CJD), Parkinson's disease (PD), primary progressive aphasia (PPA), and progressive supranuclear palsy (PSP). The LC-MS/MS method showed excellent intra- and interassay precision (4.4-7.4% and 4.9-10.3%) and accuracy (100-107% and 100-106%). CSF ubiquitin concentration was increased compared with that of controls (33.0 ± 9.7 ng/mL) in AD (47.5 ± 13.1 ng/mL, p < 0.05) and CJD patients (171.5 ± 103.5 ng/mL, p < 0.001) but not in other neurodegenerative diseases. Receiver operating characteristic curve (ROC) analysis of AD vs control patients revealed an area under the curve (AUC) of 0.832, and the specificity and sensitivity were 75 and 75%, respectively. ROC analysis of AD and FTLD patients yielded an AUC of 0.776, and the specificity and sensitivity were 53 and 100%, respectively. In conclusion, our LC-MS/MS method may facilitate ubiquitin determination to a broader community and might help to discriminate AD, CJD, and FTLD patients.

Quantum state-resolved gas/surface reaction dynamics probed by reflection absorption infrared spectroscopy

Energy Technology Data Exchange (ETDEWEB)

Chen Li [Department of Dynamics at Surfaces, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, Goettingen (Germany); Ueta, Hirokazu; Beck, Rainer D. [Laboratoire de Chimie Physique Moleculaire, Ecole Polytechnique Federale de Lausanne (Switzerland); Bisson, Regis [Aix-Marseille Universite, PIIM, CNRS, UMR 7345, 13397 Marseille (France)

2013-05-15

We report the design and characterization of a new molecular-beam/surface-science apparatus for quantum state-resolved studies of gas/surface reaction dynamics combining optical state-specific reactant preparation in a molecular beam by rapid adiabatic passage with detection of surface-bound reaction products by reflection absorption infrared spectroscopy (RAIRS). RAIRS is a non-invasive infrared spectroscopic detection technique that enables online monitoring of the buildup of reaction products on the target surface during reactant deposition by a molecular beam. The product uptake rate obtained by calibrated RAIRS detection yields the coverage dependent state-resolved reaction probability S({theta}). Furthermore, the infrared absorption spectra of the adsorbed products obtained by the RAIRS technique provide structural information, which help to identify nascent reaction products, investigate reaction pathways, and determine branching ratios for different pathways of a chemisorption reaction. Measurements of the dissociative chemisorption of methane on Pt(111) with this new apparatus are presented to illustrate the utility of RAIRS detection for highly detailed studies of chemical reactions at the gas/surface interface.

Reaction rate studies of glucose-6-phosphate dehydrogenase activity in sections of rat liver using four tetrazolium salts

NARCIS (Netherlands)

Butcher, R. G.; van Noorden, C. J.

1985-01-01

The reaction rate of glucose-6-phosphate dehydrogenase activity in liver sections from fed and starved rats has been monitored by the continuous measurement at 37 degrees C of the reaction product as it is formed using scanning and integrating microdensitometry. Control media lacked either substrate

Optical monitoring of gases with cholesteric liquid crystals

NARCIS (Netherlands)

Han, Y.; Pacheco Morillo, K.B.; Bastiaansen, C.W.M.; Broer, D.J.; Sijbesma, R.P.

2010-01-01

A new approach to optical monitors for gases is introduced using cholesteric liquid crystals doped with reactive chiral compounds. The approach is based on cholesteric pitch length changes caused by a change in helical twisting power (HTP) of the chiral dopants upon reaction with the analyte. The

Discovery of a Significant Acetone•Hydroperoxy Adduct Chaperone Effect and Its Impact on the Determination of Room Temperature Rate Constants for Acetonylperoxy/Hydroperoxy Self-Reactions and Cross Reaction Via Infrared Kinetic Spectroscopy.

Science.gov (United States)

Grieman, F. J.; Hui, A. O.; Okumura, M.; Sander, S. P.

2017-12-01

In order to model the upper troposphere/lower stratosphere in regions containing acetone properly, the kinetics of the acetonylperoxy/hydroperoxy self-reactions and cross reaction have been studied over a wide temperature range using Infrared Kinetic Spectroscopy. We report here the determination of different rate constants for the acetonylperoxy chemistry that we obtained at 298 K compared to currently accepted values. A considerable increase in the observed HO2 self-reaction rate constant due to rate enhancement via the chaperone effect from the reaction between HO2 and the (CH3)2CO•HO2 hydrogen-bonded adduct, even at room temperature, was discovered that was previously ignored. Correct determination of the acetonylperoxy and hydroperoxy kinetics must include this dependence of the HO2 self-reaction rate on acetone concentration. Via excimer laser flash photolysis to create the radical reactants, HO2 absorption was monitored in the infrared by diode laser wavelength modulation detection simultaneously with CH3C(O)CH2O2absorption monitored in the ultraviolet at 300 nm as a function of time. Resulting decay curves were fit concurrently first over a short time scale to obtain the rate constants minimizing subsequent product reactions. Modeling/fitting with a complete reaction scheme was then performed to refine the rate constants and test their veracity. Experiments were carried out over a variety of concentrations of acetone and methanol. Although no effect due to methanol concentration was found at room temperature, the rate constant for the hydroperoxy self-reaction was found to increase linearly with acetone concentration which is interpreted as the adduct being formed and resulting in a chaperone mechanism that enhances the self-reaction rate: (CH3)2CO·HO2 + HO2 → H2O2 + O2 + (CH3)2CO Including this effect, the resulting room temperature rate constants for the cross reaction and the acetonylperoxy self-reaction were found to be 2-3 times smaller than

Assumption-free analysis of quantitative real-time polymerase chain reaction (PCR) data

NARCIS (Netherlands)

Ramakers, Christian; Ruijter, Jan M.; Deprez, Ronald H. Lekanne; Moorman, Antoon F. M.

2003-01-01

Quantification of mRNAs using real-time polymerase chain reaction (PCR) by monitoring the product formation with the fluorescent dye SYBR Green I is being extensively used in neurosciences, developmental biology, and medical diagnostics. Most PCR data analysis procedures assume that the PCR

Is there room for geoengineering in the optimal climate policy mix?

International Nuclear Information System (INIS)

Bahn, Olivier; Chesney, Marc; Gheyssens, Jonathan; Knutti, Reto; Pana, Anca Claudia

2015-01-01

Highlights: • We investigate the optimal policy mix for dealing with climate change. • We consider jointly mitigation, adaptation, and solar radiation management (SRM). • SRM can control temperature, but brings environmental side-effects. • SRM is not robust due to uncertainty in magnitude and persistency of side-effects. • Implementing SRM with wrong assumptions about side-effects largely decreases welfare. - Abstract: We investigate geoengineering as a possible substitute for mitigation and adaptation measures to address climate change. Relying on an integrated assessment model, we distinguish between the effects of solar radiation management (SRM) on atmospheric temperature levels and its side-effects on the environment. The optimal climate portfolio is a mix of mitigation, adaptation, and SRM. When accounting for uncertainty in the magnitude of SRM side-effects and their persistency over time, we show that the SRM option lacks robustness. We then analyse the welfare consequences of basing the SRM decision on wrong assumptions about its side-effects, and show that total output losses are considerable and increase with the error horizon. This reinforces the need to balance the policy portfolio in favour of mitigation

Biological water quality monitoring using chemiluminescent and bioluminescent techniques

Science.gov (United States)

Thomas, R. R.

1978-01-01

Automated chemiluminescence and bioluminescence sensors were developed for the continuous monitoring of microbial levels in water supplies. The optimal chemical procedures were determined for the chemiluminescence system to achieve maximum sensitivity. By using hydrogen peroxide, reaction rate differentiation, ethylene diamine tetraacetic acid (EDTA), and carbon monoxide pretreatments, factors which cause interference were eliminated and specificity of the reaction for living and dead bacteria was greatly increased. By employing existing technology with some modifications, a sensitive and specific bioluminescent system was developed.

Photoinitiated reactions in weakly bonded complexes

International Nuclear Information System (INIS)

Wittig, C.

1993-01-01

This paper discusses photoinitiated reactions in weakly bonded binary complexes in which the constituents are only mildly perturbed by the intermolecular bond. Such complexes, with their large zero point excursions, set the stage for events that occur following electronic excitation of one of the constituents. This can take several forms, but in all cases, entrance channel specificity is imposed by the character of the complex as well as the nature of the photoinitiation process. This has enabled us to examine aspects of bimolecular processes: steric effects, chemical branching ratios, and inelastic scattering. Furthermore, monitoring reactions directly in the time domain can reveal mechanisms that cannot be inferred from measurements of nascent product excitations. Consequently, we examined several systems that had been studied previously by our group with product state resolution. With CO 2 /HI, in which reaction occurs via a HOCO intermediate, the rates agree with RRKM predictions. With N 2 O/HI, the gas phase single collision reaction yielding OH + N 2 has been shown to proceed mainly via an HNNO intermediate that undergoes a 1,3-hydrogen shift to the OH + N 2 channel. With complexes, ab initio calculations and high resolution spectroscopic studies of analogous systems suggest that the hydrogen, while highly delocalized, prefers the oxygen to the nitrogen. We observe that OH is produced with a fast risetime (< 250 fs) which can be attributed to either direct oxygen-side attack or rapid HNNO decomposition and/or a termolecular contribution involving the nearby iodine

EDXRF applied to the chemical characterization of domestic and industrial sludges

Energy Technology Data Exchange (ETDEWEB)

Silva, Gleyce Kelly A. da; Dutra, Emmanuel Damiliano, E-mail: gleyce_kelly990@hotmail.com, E-mail: emmanuel.dutra@ufpe.br [Universidade Federal de Pernambuco (UFPE), Recife, PE (Brazil); França, Elvis J. de, E-mail: ejfranca@cnen.gov.br [Centro Regional de Ciências Nucleares do Nordeste (CRCN-NE/CNEN-PE), Recife, PE (Brazil)

2017-07-01

The Energy Dispersion X-ray Fluorescence – EDXRF is a low-cost, fast, non-destructible analytical technique, useful for analyzing diverse geological samples. The determination of chemical elements by EDXRF in solid urban wastes is economic and operationally feasible, since the concentration of many heavy metals can be easily monitored. Besides, chemical elements as aluminum and some minerals that compose important natural cycles add valuable information for deciding the final destination of these wastes. The objective of this work was the obtaining the analytical curves for quantifying chemical elements by EDXRF in sewage sludge. For this, analytical portions (1 g) of the certified reference materials SRM 2781 Domestic Sludge and SRM 2782 Industrial Sludge produced by the National Institute of Standards and Technology (NIST) were transferred to polyethylene tubes and sealed at the top and bottom with polypropylene film specific for EDXRF analysis. Exactly 500 mg of each of the above SRMs were mixed by means of a ball mill for composing the SRM MIX, also analyzed for obtaining the analytical curves. All samples were analyzed in an atmosphere close to the vacuum (less than 30 Pa), with dead time less than 35%. For Al, As, Cu, Fe, K, Ni, Pb, Si, Ti and Zn, linear regressions have been fitted with respective linear coefficients higher than 0.95. To evaluate the quality of the analytical procedure, an independent test portion of the reference material SRM 2781 Sludge Domestic was used, calculating the Number En obtaining values between -1 and 1, range considered adequate for the quality assurance at the 95% confidence level. (author)

EDXRF applied to the chemical characterization of domestic and industrial sludges

International Nuclear Information System (INIS)

Silva, Gleyce Kelly A. da; Dutra, Emmanuel Damiliano; França, Elvis J. de

2017-01-01

The Energy Dispersion X-ray Fluorescence – EDXRF is a low-cost, fast, non-destructible analytical technique, useful for analyzing diverse geological samples. The determination of chemical elements by EDXRF in solid urban wastes is economic and operationally feasible, since the concentration of many heavy metals can be easily monitored. Besides, chemical elements as aluminum and some minerals that compose important natural cycles add valuable information for deciding the final destination of these wastes. The objective of this work was the obtaining the analytical curves for quantifying chemical elements by EDXRF in sewage sludge. For this, analytical portions (1 g) of the certified reference materials SRM 2781 Domestic Sludge and SRM 2782 Industrial Sludge produced by the National Institute of Standards and Technology (NIST) were transferred to polyethylene tubes and sealed at the top and bottom with polypropylene film specific for EDXRF analysis. Exactly 500 mg of each of the above SRMs were mixed by means of a ball mill for composing the SRM MIX, also analyzed for obtaining the analytical curves. All samples were analyzed in an atmosphere close to the vacuum (less than 30 Pa), with dead time less than 35%. For Al, As, Cu, Fe, K, Ni, Pb, Si, Ti and Zn, linear regressions have been fitted with respective linear coefficients higher than 0.95. To evaluate the quality of the analytical procedure, an independent test portion of the reference material SRM 2781 Sludge Domestic was used, calculating the Number En obtaining values between -1 and 1, range considered adequate for the quality assurance at the 95% confidence level. (author)

Development and validation of LC-MS/MS method with multiple reactions monitoring mode for quantification of vanillin and syringaldehyde in plum brandies

Directory of Open Access Journals (Sweden)

Tešević Vele

2014-01-01

Full Text Available An ultra-performance liquid chromatography-triple quadrupole mass spectrometry (UPLC-QqQ-MS/MS method with multiple reactions monitoring mode (MRM has been developed and validated for quantification of vanillin and syringaldehyde in plum brandy. The method showed good linearity (0.05 to 10 mgL−1 and low limits of detection and quantification (LOD and LOQ were 11.6 µgL−1 and 38.2 µgL−1 for vanillin, and 12.7 µgL−1 and 42.0 µgL−1 for syringaldehyde, respectively. The overall intra-day and inter-day variations were less than 4.21%, and the overall recovery over 93.0%. The correlation coefficients (R2 of the calibration curves were higher than 0.9999. In order to evaluate if the method is suitable for use as a routine analytical tool, in 31 Serbian plum brandy samples vanillin and syringaldehide were determined. [Projekat Ministarstva nauke Republike Srbije, br. 172053

Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

Science.gov (United States)

Huang, Cancan; Jevric, Martyn; Borges, Anders; Olsen, Stine T.; Hamill, Joseph M.; Zheng, Jue-Ting; Yang, Yang; Rudnev, Alexander; Baghernejad, Masoud; Broekmann, Peter; Petersen, Anne Ugleholdt; Wandlowski, Thomas; Mikkelsen, Kurt V.; Solomon, Gemma C.; Brøndsted Nielsen, Mogens; Hong, Wenjing

2017-05-01

Charge transport by tunnelling is one of the most ubiquitous elementary processes in nature. Small structural changes in a molecular junction can lead to significant difference in the single-molecule electronic properties, offering a tremendous opportunity to examine a reaction on the single-molecule scale by monitoring the conductance changes. Here, we explore the potential of the single-molecule break junction technique in the detection of photo-thermal reaction processes of a photochromic dihydroazulene/vinylheptafulvene system. Statistical analysis of the break junction experiments provides a quantitative approach for probing the reaction kinetics and reversibility, including the occurrence of isomerization during the reaction. The product ratios observed when switching the system in the junction does not follow those observed in solution studies (both experiment and theory), suggesting that the junction environment was perturbing the process significantly. This study opens the possibility of using nano-structured environments like molecular junctions to tailor product ratios in chemical reactions.

Acoustic sodium-water reaction detection of the Phenix steam generators

International Nuclear Information System (INIS)

Carminati, M.; Martin, L.; Sauzaret, A.

1990-01-01

The systems for acoustic sodium-water reaction detection and hydrogen detection of the Phenix steam generators as well as systems for monitoring signals analysis and processing are described. It is reported that the results obtained during operation and calibration phases are very encouraging and that industrial equipment showing the same performance are being examined. 6 figs

Sensitive electrochemical monitoring of nucleic acids coupling DNA nanostructures with hybridization chain reaction

International Nuclear Information System (INIS)

Zhuang, Junyang; Fu, Libing; Xu, Mingdi; Yang, Huanghao; Chen, Guonan; Tang, Dianping

2013-01-01

Graphical abstract: -- Highlights: •A new signal-on metallobioassay was developed for detection of nucleic acids. •Target-triggered long-range self-assembled DNA nanostructures are used for amplification of electronic signal. •Hybridization chain reaction is utilized for construction of long-range DNA nanostructures. -- Abstract: Methods based on metal nanotags have been developed for metallobioassay of nucleic acids, but most involve complicated labeling or stripping procedures and are unsuitable for routine use. Herein, we report the proof-of-concept of a novel and label-free metallobioassay for ultrasensitive electronic determination of human immunodeficiency virus (HIV)-related gene fragments at an ultralow concentration based on target-triggered long-range self-assembled DNA nanostructures and DNA-based hybridization chain reaction (HCR). The signal is amplified by silver nanotags on the DNA duplex. The assay mainly consists of capture probe, detection probe, and two different DNA hairpins. In the presence of target DNA, the capture probe immobilized on the sensor sandwiches target DNA with the 3′ end of detection probe. Another exposed part of detection probe at the 5′ end opens two alternating DNA hairpins in turn, and propagates a chain reaction of hybridization events to form a nicked double-helix. Finally, numerous silver nanotags are immobilized onto the long-range DNA nanostructures, each of which produces a strong electronic signal within the applied potentials. Under optimal conditions, the target-triggered long-range DNA nanostructures present good electrochemical behaviors for the detection of HIV DNA at a concentration as low as 0.5 fM. Importantly, the outstanding sensitivity can make this approach a promising scheme for development of next-generation DNA sensors without the need of enzyme labeling or fluorophore labeling

Automatic duress alarms through physiological response monitoring

International Nuclear Information System (INIS)

Roehrig, S.C.

1977-07-01

Physiological response monitoring under controlled conditions can provide an effective means for passively determining if the wearer is under moderate to severe stresses. By monitoring the heart rate (HR) and galvanic skin response (GSR) of an individual, it is possible to detect in real time the increase in heart rate and GSR levels due to physiological reactions to mental duress. With existing physiological monitoring equipment, however, the work load of the wearer must be well defined since it is impossible, without additional data, to distinguish mental duress responses from those resulting from moderate physical exertion. Similarly, environmental conditions should be constrained within set limits to avoid masking increases in GSR levels due to metntal stress from those associated with increased perspiration. These constraints should not prove overly restrictive and would allow an integrated security system utilizing physiological monitoring equipment to provide an effective real time, automated early warning system for detection of mental duress or death of the wearer

Multiple reaction monitoring (MRM)-profiling for biomarker discovery applied to human polycystic ovarian syndrome.

Science.gov (United States)

Cordeiro, Fernanda B; Ferreira, Christina R; Sobreira, Tiago Jose P; Yannell, Karen E; Jarmusch, Alan K; Cedenho, Agnaldo P; Lo Turco, Edson G; Cooks, R Graham

2017-09-15

We describe multiple reaction monitoring (MRM)-profiling, which provides accelerated discovery of discriminating molecular features, and its application to human polycystic ovary syndrome (PCOS) diagnosis. The discovery phase of the MRM-profiling seeks molecular features based on some prior knowledge of the chemical functional groups likely to be present in the sample. It does this through use of a limited number of pre-chosen and chemically specific neutral loss and/or precursor ion MS/MS scans. The output of the discovery phase is a set of precursor/product transitions. In the screening phase these MRM transitions are used to interrogate multiple samples (hence the name MRM-profiling). MRM-profiling was applied to follicular fluid samples of 22 controls and 29 clinically diagnosed PCOS patients. Representative samples were delivered by flow injection to a triple quadrupole mass spectrometer set to perform a number of pre-chosen and chemically specific neutral loss and/or precursor ion MS/MS scans. The output of this discovery phase was a set of 1012 precursor/product transitions. In the screening phase each individual sample was interrogated for these MRM transitions. Principal component analysis (PCA) and receiver operating characteristic (ROC) curves were used for statistical analysis. To evaluate the method's performance, half the samples were used to build a classification model (testing set) and half were blinded (validation set). Twenty transitions were used for the classification of the blind samples, most of them (N = 19) showed lower abundances in the PCOS group and corresponded to phosphatidylethanolamine (PE) and phosphatidylserine (PS) lipids. Agreement of 73% with clinical diagnosis was found when classifying the 26 blind samples. MRM-profiling is a supervised method characterized by its simplicity, speed and the absence of chromatographic separation. It can be used to rapidly isolate discriminating molecules in healthy/disease conditions by

Targeted proteomics guided by label-free global proteome analysis in saliva reveal transition signatures from health to periodontal disease.

Science.gov (United States)

Bostanci, Nagihan; Selevsek, Nathalie; Wolski, Witold; Grossmann, Jonas; Bao, Kai; Wahlander, Asa; Trachsel, Christian; Schlapbach, Ralph; Özturk, Veli Özgen; Afacan, Beral; Emingil, Gulnur; Belibasakis, Georgios N

2018-04-02

Periodontal diseases are among the most prevalent worldwide, but largely silent, chronic diseases. They affect the tooth-supporting tissues with multiple ramifications on life quality. Their early diagnosis is still challenging, due to lack of appropriate molecular diagnostic methods. Saliva offers a non-invasively collectable reservoir of clinically relevant biomarkers, which, if utilized efficiently, could facilitate early diagnosis and monitoring of ongoing disease. Despite several novel protein markers being recently enlisted by discovery proteomics, their routine diagnostic application is hampered by the lack of validation platforms that allow for rapid, accurate and simultaneous quantification of multiple proteins in large cohorts. We carried out a pipeline of two proteomic platforms; firstly, we applied open ended label-free quantitative (LFQ) proteomics for discovery in saliva (n=67, health, gingivitis, and periodontitis), followed by selected-reaction monitoring (SRM)-targeted proteomics for validation in an independent cohort (n=82). The LFQ platform led to the discovery of 119 proteins with at least two-fold significant difference between health and disease. The 65 proteins chosen for the subsequent SRM platform included 50 related proteins derived from the significantly enriched processes of the LFQ data, 11 from literature-mining, and four house-keeping ones. Among those, 60 were reproducibly quantifiable proteins (92% success rate), represented by a total of 143 peptides. Machine-learning modeling led to a narrowed-down panel of five proteins of high predictive value for periodontal diseases (higher in disease: Matrix metalloproteinase-9, Ras-related protein-1, Actin-related protein 2/3 complex subunit 5; lower in disease: Clusterin, Deleted in Malignant Brain Tumors 1), with maximum area under the receiver operating curve >0.97. This panel enriches the pool of credible clinical biomarker candidates for diagnostic assay development. Yet, the quantum

Monitoring of Plutonium Contaminated Solid Waste Streams. A technical guide to design and analysis of monitoring systems

International Nuclear Information System (INIS)

Birkhoff, G.

1985-06-01

The basic information on the Pu content in Pu Contaminated Materials (PCM) is the measurement of radiation emitted by Pu isotopes either spontaneously or due to irradiation by external neutron or gamma-sources. Requirements on measurement accuracy and detection limits should be defined by the operator of a Pu-handling facility in accordance with monitoring objectives in the very beginning of the planning of a monitoring system. Monitoring objectives reflect nuclear safety and radiological protection regulations and the needs for Pu-accountancy of nuclear materials management and safeguards. On considering the possibilities and limitations of radiometric techniques a solution of the monitoring problem is based on appropriate segregation and packaging procedures and records upon matrix and isotopic composition of PCM-items to be measured. The general interrelations between waste item characteristics and measurement uncertainty and detection limit are outlined in the first chapter which is addressed to the system planner. Chapter 2 is devoted to the attention of instrument developers and analysts. It presents in a general approach the correlations between the observed radiation leakage rate, respectively detection signal, and the generating source, e.g. Pu-isotopic content of the examined PCM item. Some practical measurement methods are reviewed and their limitations are indicated. The possible radiometric techniques based on detection of gamma rays from alpha decay (and 241 Am), neutrons from spontaneous fission and (α,n)-reaction and from induced fission reactions by neutron irradiation of Pu isotopes are presented. The measurement uncertainty of a single PCM item measurement is estimated on the basis of the uncertainty of the spatial distributions of source (Pu) and matrix materials. For the estimation of the cumulative error over a large collection of PCM items from a defined PCM-stream a probabilistic approach is suggested

Absolute calibration of the Rh-103(n,n')Rh-103m reaction rate

International Nuclear Information System (INIS)

Taylor, W.H.; Murphy, M.F.; March, M.R.

1979-05-01

The uncertainties in determining the absolute values of the Rh-103(n, n') Rh-103m reaction rate (which is widely used as a neutron damage flux monitor) have been reduced to approximately +-5%. This has been achieved with the use of a calibrated source of Pd-103-Rh-103m activity supplied by the IAEA. Agreement to within 3% between measured and calculated values of the reaction rate (normalised to the U-238 fission rate) has been achieved. (author)

Self-reported adverse reactions among patients initiating antiretroviral therapy in Brazil

Directory of Open Access Journals (Sweden)

Cristiane A. Menezes de Pádua

Full Text Available A cross-sectional analysis was carried out to describe adverse reactions to antiretroviral therapy (ART reported by HIV-infected patients initiating treatment at two public health AIDS referral centers in Belo Horizonte, Brazil, 2001-2003 and to verify their association with selected variables. Adverse reactions were obtained through interview at the first follow-up visit (first month after the antiretroviral prescription. Socio-demographic and behavioral variables related to ART were obtained from baseline and follow-up interviews and clinical variables from medical charts. Patients with four or more reactions were compared to those with less than four. Odds ratio with 95% confidence interval were estimated using logistic regression model for both univariate and multivariate analyses. At least one adverse reaction was reported by 92.2% of the participants while 56.2% reported four or more different reactions. Antiretroviral regimens including indinavir/ritonavir, irregular use of antiretrovirals and switch in regimens were independently associated with four or more adverse reactions (OR=7.92, 5.73 and 2.03, respectively. The initial period of ARV treatment is crucial and patients´ perception of adverse reactions should be carefully taken into account. Strategies for monitoring and management of adverse reactions including the choice of regimens and the prevention of irregular ART should be developed in AIDS/HIV referral centers in Brazil to promote better adherence to antiretroviral therapy.

Measurements of the thermal neutron cross-section and resonance integral for the 108Pd(n,γ)109Pd reaction

Science.gov (United States)

Hien, Nguyen Thi; Kim, Guinyun; Kim, Kwangsoo; Do, Nguyen Van; Khue, Pham Duc; Thanh, Kim Tien; Shin, Sung-Gyun; Cho, Moo-Hyun

2018-06-01

The thermal neutron capture cross-section (σ0) and resonance integral (I0) of the 108Pd(n,γ)109Pd reaction have been measured relative to that of the monitor reaction 197Au(n,γ)198Au. The measurements were carried out using the neutron activation with the cadmium ratio method. Both the samples and monitors were irradiated with and without cadmium cover of 0.5 mm thickness. The induced activities of the reaction products were measured with a well calibrated HPGe γ-ray detector. In order to improve the accuracy of the results, the necessary corrections for the counting losses were made. The thermal neutron capture cross-section and resonance integral of the 108Pd(n,γ)109Pd reaction were determined to be σ0,Pd = 8.68 ± 0.41 barn and I0,Pd = 245.6 ± 24.8 barn, respectively. The obtained results are compared with literature values and discussed.

Modelling the Maillard reaction during the cooking of a model cheese.

Science.gov (United States)

Bertrand, Emmanuel; Meyer, Xuân-Mi; Machado-Maturana, Elizabeth; Berdagué, Jean-Louis; Kondjoyan, Alain

2015-10-01

During processing and storage of industrial processed cheese, odorous compounds are formed. Some of them are potentially unwanted for the flavour of the product. To reduce the appearance of these compounds, a methodological approach was employed. It consists of: (i) the identification of the key compounds or precursors responsible for the off-flavour observed, (ii) the monitoring of these markers during the heat treatments applied to the cheese medium, (iii) the establishment of an observable reaction scheme adapted from a literature survey to the compounds identified in the heated cheese medium (iv) the multi-responses stoichiokinetic modelling of these reaction markers. Systematic two-dimensional gas chromatography time-of-flight mass spectrometry was used for the semi-quantitation of trace compounds. Precursors were quantitated by high-performance liquid chromatography. The experimental data obtained were fitted to the model with 14 elementary linked reactions forming a multi-response observable reaction scheme. Copyright © 2015 Elsevier Ltd. All rights reserved.

Core Sulphate-Reducing Microorganisms in Metal-Removing Semi-Passive Biochemical Reactors and the Co-Occurrence of Methanogens

Directory of Open Access Journals (Sweden)

Maryam Rezadehbashi

2018-02-01

Full Text Available Biochemical reactors (BCRs based on the stimulation of sulphate-reducing microorganisms (SRM are emerging semi-passive remediation technologies for treatment of mine-influenced water. Their successful removal of metals and sulphate has been proven at the pilot-scale, but little is known about the types of SRM that grow in these systems and whether they are diverse or restricted to particular phylogenetic or taxonomic groups. A phylogenetic study of four established pilot-scale BCRs on three different mine sites compared the diversity of SRM growing in them. The mine sites were geographically distant from each other, nevertheless the BCRs selected for similar SRM types. Clostridia SRM related to Desulfosporosinus spp. known to be tolerant to high concentrations of copper were members of the core microbial community. Members of the SRM family Desulfobacteraceae were dominant, particularly those related to Desulfatirhabdium butyrativorans. Methanogens were dominant archaea and possibly were present at higher relative abundances than SRM in some BCRs. Both hydrogenotrophic and acetoclastic types were present. There were no strong negative or positive co-occurrence correlations of methanogen and SRM taxa. Knowing which SRM inhabit successfully operating BCRs allows practitioners to target these phylogenetic groups when selecting inoculum for future operations.

Optimization of Maillard Reaction between Glucosamine and Other Precursors by Measuring Browning with a Spectrophotometer.

Science.gov (United States)

Ogutu, Benrick; Kim, Ye-Joo; Kim, Dae-Wook; Oh, Sang-Chul; Hong, Dong-Lee; Lee, Yang-Bong

2017-09-01

The individual Maillard reactions of glucose, glucosamine, cyclohexylamine, and benzylamine were studied at a fixed temperature of 120°C under different durations by monitoring the absorbance of the final products at 425 nm. Glucosamine was the most individually reactive compound, whereas the reactions of glucose, cyclohexylamine, and benzylamine were not significantly different from each other. Maillard reactions of reaction mixtures consisting of glucosamine-cyclohexylamine, glucosamine-benzylamine, glucose-cyclohexylamine, and glucose-benzylamine were also studied using different concentration ratios under different durations at a fixed temperature of 120°C and pH 9. Maillard reactions in the pairs involving glucosamine were observed to be more intense than those of the pairs involving glucose. Finally, with respect to the concentration ratios, it was observed that in most instances, optimal activity was realized, when the reaction mixtures were in the ratio of 1:1.

(n,α reactions cross section research at IPPE

Directory of Open Access Journals (Sweden)

Giorginis G.

2012-02-01

Full Text Available An experimental set-up based on an ionization chamber with a Frisch grid and wave form digitizer was used for (n,α cross section measurements. Use of digital signal processing allowed us to select a gaseous cell inside the sensitive area of the ionization chamber and determine the target atoms in it with high accuracy. This kind of approach provided us with a powerful method to suppress background arising from the detector structure and parasitic reactions on the working gas components. This method is especially interesting to study neutron reactions with elements for which solid target preparation is difficult (noble gases for example. In the present experiments we used a set of working gases which contained admixtures of nitrogen, oxygen, neon, argon and boron. Fission of 238U was used as neutron flux monitor. The cross section of the (n,α reaction for 16O, 14N, 20Ne, 36Ar, 40Ar and the yield ratio α0/α1 of 10B(n,α0 to 10B(n,α1 reactions was measured for neutron energies between 1.5 and 7 MeV. Additionally a measurement of the 50Cr(n,α cross section using a solid chromium target is also reported.

Surface confined retro Diels-Alder reaction driven by the swelling of weak polyelectrolytes.

Science.gov (United States)

Lyu, Beier; Cha, Wenli; Mao, Tingting; Wu, Yuanzi; Qian, Hujun; Zhou, Yitian; Chen, Xiuli; Zhang, Shen; Liu, Lanying; Yang, Guang; Lu, Zhongyuan; Zhu, Qiang; Ma, Hongwei

2015-03-25

Recently, the type of reactions driven by mechanical force has increased significantly; however, the number of methods for activating those mechanochemical reactions stays relatively limited. Furthermore, in situ characterization of a reaction is usually hampered by the inherent properties of conventional methods. In this study, we report a new platform that utilizes mechanical force generated by the swelling of surface tethered weak polyelectrolytes. An initiator with Diels-Alder (DA) adduct structure was applied to prepare the polyelectrolyte-carboxylated poly(OEGMA-r-HEMA), so that the force could trigger the retro DA reaction. The reaction was monitored in real time by quartz crystal microbalance and confirmed with atomic force microscopy and X-ray photoelectron spectroscopy. Compared with the conventional heating method, the swelling-induced retro DA reaction proceeded rapidly with high conversion ratio and selectivity. A 23.61 kcal/mol theoretical energy barrier supported the practicability of this retro DA reaction being triggered mechanically at ambient temperature. During swelling, the tensile force was controllable and persistent. This unique feature imparts this mechanochemical platform the potential to "freeze" an intermediate state of a reaction for in situ spectroscopic observations, such as surface-enhanced Raman spectroscopy and frequency generation spectroscopy.

Productions of Volatile Organic Compounds (VOCs) in Surface Waters from Reactions with Atmospheric Ozone

Science.gov (United States)

Hopkins, Frances; Bell, Thomas; Yang, Mingxi

2017-04-01

Ozone (O3) is a key atmospheric oxidant, greenhouse gas and air pollutant. In marine environments, some atmospheric ozone is lost by reactions with aqueous compounds (e.g. dissolved organic material, DOM, dimethyl sulfide, DMS, and iodide) near the sea surface. These reactions also lead to formations of volatile organic compounds (VOCs). Removal of O3 by the ocean remains a large uncertainty in global and regional chemical transport models, hampering coastal air quality forecasts. To better understand the role of the ocean in controlling O3 concentrations in the coastal marine atmosphere, we designed and implemented a series of laboratory experiments whereby ambient surface seawater was bubbled with O3-enriched, VOC-free air in a custom-made glass bubble equilibration system. Gas phase concentrations of a range of VOCs were monitored continuously over the mass range m/z 33 - 137 at the outflow of the bubble equilibrator by a proton transfer reaction - mass spectrometer (PTR-MS). Gas phase O3 was also measured at the input and output of the equilibrator to monitor the uptake due to reactions with dissolved compounds in seawater. We observed consistent productions of a variety of VOCs upon reaction with O3, notably isoprene, aldehydes, and ketones. Aqueous DMS is rapidly removed from the reactions with O3. To test the importance of dissolved organic matter precursors, we added increasing (milliliter) volumes of Emiliania huxleyi culture to the equilibrator filled with aged seawater, and observed significant linear increases in gas phase concentrations of a number of VOCs. Reactions between DOM and O3 at the sea-air interface represent a potentially significant source of VOCs in marine air and a sink of atmospheric O3.

Weighing and Body Monitoring among College Women: The Scale Number as an Emotional Barometer

Science.gov (United States)

Mintz, Laurie B.; Awad, Germine H.; Stinson, Rebecca D.; Bledman, Rashanta A.; Coker, Angela D.; Kashubeck-West, Susan; Connelly, Kathleen

2013-01-01

This study investigated weighing and body-monitoring behaviors, as well as psychological and behavioral reactions to weighing, among female college students. Weighing and body monitoring were engaged in by the majority of participants. Participants changed food intake and exercise based on weight. About 63% reported that the scale number impacts…

New excitation functions for proton induced reactions on natural titanium, nickel and copper up to 70 MeV

Energy Technology Data Exchange (ETDEWEB)

Garrido, E. [SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS/IN2P3, Nantes (France); Duchemin, C., E-mail: Charlotte.Duchemin@subatech.in2p3.fr [SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS/IN2P3, Nantes (France); Guertin, A. [SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS/IN2P3, Nantes (France); Haddad, F.; Michel, N. [SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS/IN2P3, Nantes (France); GIP Arronax, 1 rue Aronnax, 44817 Saint-Herblain (France); Métivier, V. [SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS/IN2P3, Nantes (France)

2016-09-15

Highlights: • Natural titanium, nickel and copper targets. • 70 MeV ARRONAX cyclotron proton beam. • Stacked-foil technique and monitor reactions. • Experimental cross section values. • TALYS code version 1.6. - Abstract: New excitation functions for proton induced nuclear reactions on natural titanium, nickel and copper were measured, using the stacked-foil technique and gamma spectrometry, up to 70 MeV. The experimental cross sections were measured using the Ti-nat(p,x) V-48, Ni-nat(p,x) Ni-57 and Cu-nat(p,x) Zn-62,Co-56 monitor reactions recommended by the International Atomic Energy Agency (IAEA), depending on the investigated energy range. Data have been extracted for the Ti-nat(p,x) Sc-43,44m,46,47,48, V-48, K-42,43, Ni-nat(p,x) Ni-56,57, Co-55,56,57,58, Mn-52,54, Cu-nat(p,x) Cu-61,64, Ni-57, Co-56,57,58,60, Zn-62,65, Mn-54 reactions. Our results are discussed and compared to the existing ones as well as with the TALYS code version 1.6 calculations using default models. Our experimental data are in overall good agreement with the literature. TALYS is able to reproduce, in most cases, the experimental trend. Our new experimental results allow to expand our knowledge on these excitation functions, to confirm the existing trends and to give additional values on a large energy range. This work is in line with the new Coordinated Research Project (CRP) launched by the IAEA to expand the database of monitor reactions.

Schreibersite: an effective catalyst in the formose reaction network

Science.gov (United States)

Pallmann, S.; Šteflová (neé Svobodová, J.; Haas, M.; Lamour, S.; Henß, A.; Trapp, O.

2018-05-01

We report on the ability of the meteoritic material schreibersite to catalyze the generation of higher sugars from simple carbohydrates in the formose reaction network. Since the analysis of carbonaceous meteorites like the Murchison meteorite it has become generally accepted that a substantial amount of organic material has been delivered to the early earth and, therefore, ought to be considered in scenarios for the origin(s) of life. Also for the open question of accessible phosphorus sources, an extraterrestrial material called schreibersite has been identified that is capable of releasing soluble and reactive phosphorus oxyanions that would react with organics to form for instance nucleotides and membrane associated molecules. We have reinvestigated this material using capillary electrophoresis to monitor its corrosion process in water and probed its ability to phosphorylate a wide range of organics. Although showing a poor reactivity of schreibersite, we have found that the material catalyzes the aldol reaction of small carbohydrates forming larger sugar molecules. This reaction in the formose reaction network is a prebiotically likely route to biologically relevant sugars. The results of our study present one of the first instances of connecting extraterrestrial material to prebiotic chemistry on the early earth.

Cutaneous drug reaction case reports: from the world literature.

Science.gov (United States)

2003-01-01

Skin disorders are the most common adverse reactions attributed to drugs. Any skin disorder can be imitated, induced or aggravated by drugs. To help you keep up-to-date with the very latest skin reactions occurring with both new and established drugs, this section of the journal brings you information selected from the adverse drug reaction alerting service Reactions Weekly. Reactions Weekly is the complete drug safety alerting service and summarizes information selected from over 1600 biomedical journals. This newsletter is produced by Adis International and is available in a variety of formats. Please contact your nearest Adis office for subscription details. The use of tradenames, identified by ['~'] or the use of a registered ((R)) or trade mark ( trade mark ), is for product identification purposes only and does not imply endorsement. The following case reports are selected from the very latest to be published in the world dermatology literature. Any claim of a first report has been verified by a search of AdisBase (a proprietary database of Adis International) and Medline. In addition, the World Health Organization (WHO) Adverse Drug Reactions database is also searched. This database, maintained by the Uppsala Monitoring Centre in Sweden, is the largest and most comprehensive adverse drug reaction source in the world, with information obtained from National Centers of 65 affiliate countries. Each case report is assessed for seriousness using the FDA MedWatch definition of serious (patient outcome is: death; life-threatening; hospitalization; disability; congenital anomaly; or requires intervention to prevent permanent impairment or damage).

Conductometric Microbiosensors for Environmental Monitoring

Directory of Open Access Journals (Sweden)

Sergei V. Dzyadevych

2008-04-01

Full Text Available This review presents the principles of conductometric measurements in ionic media and the equivalent electrical circuits of different designs for conductometric measurements. These types of measurements were first applied for monitoring biocatalytic reactions. The use of conductometric microtransducers is then presented and detailed in the case of pollutant detection for environmental monitoring. Conductometric biosensors have advantages over other types of transducers: they can be produced through inexpensive thinfilm standard technology, no reference electrode is needed and differential mode measurements allow cancellation of a lot of interferences. The specifications obtained for the detection of different pesticides, herbicides and heavy metal ions, based on enzyme inhibition, are presented as well as those obtained for the detection of formaldehyde, 4- chlorophenol, nitrate and proteins as markers of dissolved organic carbon based on enzymatic microbiosensors.

Intensive monitoring of new drugs based on first prescription signals from pharmacists : a pilot study

NARCIS (Netherlands)

Van Grootheest, AC; Groote, JK; de Jong-van den Berg, LTW

Background Intensive monitoring can be a valuable tool in the early detection of adverse drug reactions, especially of new drugs. Aim of this pilot study was to investigate the practical possibilities of a system of intensive monitoring, using the pharmacy computer system to detect the first

Determination of trace elements in standard reference materials by the ko-standardization method

International Nuclear Information System (INIS)

Smodis, B.; Jacimovic, R.; Stegnar, P.; Jovanovic, S.

1990-01-01

The k o -standardization method is suitable for routine multielement determinations by reactor neutron activation analysis (NAA). Investigation of NIST standard reference materials SRM 1571 Orchard Leaves, SRM 1572 Citrus leaves, and SRM 1573 Tomato Leaves showed the systematic error of 12 certified elements determined to be less than 8%. Thirty-four elements were determined in NIST proposed SRM 1515 Apple Leaves

Isotope Effects in the Reactions of Chloroform Isotopologues with Cl, OH and OD

DEFF Research Database (Denmark)

Nilsson, Elna Johanna Kristina; Johnson, Matthew Stanley; Nielsen, Claus J.

2009-01-01

The kinetic isotope effects in the reactions of CHCl3, CDCl3, and 13CHCl3 with Cl, OH, and OD radicals have been determined in relative rate experiments at 298 ( 1 K and atmospheric pressure monitored by long path FTIR spectroscopy. The spectra were analyzed using a nonlinear least-squares spectral.......002, kCHCl3+OD/kCDCl3+OD ) 3.95 ( 0.03, and kCHCl3+OD/k13CHCl3+OD ) 1.032 ( 0.004. Larger isotope effects in the OH reactions than in the Cl reactions are opposite to the trends for CH4 and CH3Cl reported in the literature. The origin of these differences was investigated using electronic structure...

Coal ash monitoring equipment

Energy Technology Data Exchange (ETDEWEB)

Clayton, C G; Wormald, M R

1978-10-02

The monitoring equipment is used to determine the remainder from combustion (ash slack) of coal in wagons designed for power stations. Next to the rails, a neutron source (252 Cf, 241 Am/Be) is situated, which irradiates the coal with neutrons at a known dose, which produces the reaction 27 Al (n ..gamma..) Al 28. The aluminium content is a measure of the remainder. The 1.78 MeV energy is measured downstream of the rail with a detector. The neutron source can only act in the working position of a loaded wagon.

Absolute calibration of the Rh-103 (n, n') Rh-103m reaction rate

International Nuclear Information System (INIS)

Taylor, W.H.; Murphy, M.F.; March, M.R.

1979-05-01

The uncertainties in determining the absolute values of the Rh-103 (n, n') Rh-103m reaction rate (which is widely used as a neutron damage flux monitor) have been reduced to ∼±5%. This has been achieved with the use of a calibrated source of Pd-103-Rh-103m activity supplied by the I.A.E.A. Agreement to within 3% between measured and calculated values of the reaction rate (normalised to the U-238 fission rate) has been achieved. (author)

Evaluation of adverse reactions to contrast media in the hospital

Science.gov (United States)

Ryu, J-H; Kim, E-Y

2013-01-01

Objective: To determine and analyse the characteristics of contrast media adverse reactions (CM-ARs) reported in a hospital. Methods: A retrospective review of CM-ARs from the electronic spontaneous adverse drug reaction (ADR) report system between January 2011 and August 2012 was conducted. CM-ARs were evaluated in terms of causality, severity, preventability and affected organs. Also, agreement and correlation among the tools used to evaluate CM-ARs were analysed. Results: The overall reaction rate was 1.5% (n = 286). In total, 269 CM-ARs were identified. For ADR causality, 96.7% (n = 260) and 98.5% (n = 265) were evaluated as “probable” ADR using the Naranjo probability scale and the World Health Organization–Uppsala Monitoring Centre causality categories, whereas 98.1% (n = 264) were evaluated as “certain” with Korean algorithm v. II. Of these, 91.4% (n = 246) were mild in severity and 96.7% (n = 260) were unpreventable. Most patients (n = 233, 86.7%) could be managed with observation and/or simple treatment. The most frequent reaction (n = 383, 79.5%) was dermatological. Spearman's correlation coefficient was 0.667 (p < 0.01), and the agreement was 98.1% between the Naranjo scale and the World Health Organization–Uppsala Monitoring Centre categories. No relationship was seen between CM-AR severity and gender or between in- and outpatients. Conclusion: In our study, most CM-ARs were mild and managed with simple treatment. However, as the number of patients undergoing CT procedures continues to increase, it is essential to identify and observe patients at risk for CM-ARs to prevent severe ADRs. Advances in knowledge: Continuous careful review of reporting and treatment protocols of CM-ARs is needed to prevent morbidity and mortality. PMID:24191123

Development of a liquid chromatography-electrospray chemical ionization tandem mass spectrometry analytical method for analysis of eleven hydroxylated polybrominated diphenyl ethers.

Science.gov (United States)

Feo, Maria Luisa; Barón, Enrique; Aga, Diana S; Eljarrat, Ethel; Barceló, Damià

2013-08-02

Recently, hydroxylated polybrominated diphenyl ethers (OH-PBDEs) have emerged as environmentally relevant pollutants due to recent reports of their natural production and metabolism. Recent mechanistic studies in human and rats have shown that some OH-PBDEs are more potent than parent compounds (PBDEs) and may contribute substantially to neurodevelopmental disorders by direct neurotoxicity, or indirectly through altered thyroid disruption. However, analytical methodologies for determination of OH-PBDEs are currently limited. In this study a robust liquid chromatography-electrospray tandem triple quadrupole-linear ion trap mass spectrometer (LC-ESI-QqLIT-MS-MS) in negative mode method was developed for the determination of eleven OH-tri- to OH-hexa-PBDEs. Two different columns were tested and compared for chromatographic separation: a C18 BetaBasic and a Purospher STAR RP 18, working at pH 8 and 10, respectively. Mobile phase (acetonitrile:water) was optimized by changing the pH of the aqueous phase and the concentration of the organic modifier (methanol). The MS-MS parameters (declustering potential (DP), collision energy (CE) and cell exit potential (CXP)) were optimized. Selected reaction monitoring (SRM) was used in order to increase sensitivity. Two SRM transitions ([M-H](-)>[Br](-)) were selected for each OH-PBDE, one for quantification and the second one for confirmation. Under the optimized conditions, the instrumental limits of detection were between 0.17 and 0.72injectedpg. The method provided good linearity (r>0.99 for a concentration range of 0.30-100ng/mL), accuracy and precision (%Dev and %RSD≤20% for intra- and inter-assays). Copyright © 2013 Elsevier B.V. All rights reserved.

Alternative CHCA-based matrices for the analysis of low molecular weight compounds by UV-MALDI-tandem mass spectrometry.

Science.gov (United States)

Porta, Tiffany; Grivet, Chantal; Knochenmuss, Richard; Varesio, Emmanuel; Hopfgartner, Gérard

2011-02-01

Analysis of low molecular weight compounds (LMWC) in complex matrices by vacuum matrix-assisted laser desorption/ionization (MALDI) often suffers from matrix interferences, which can severely degrade limits of quantitation. It is, therefore, useful to have available a range of suitable matrices, which exhibit complementary regions of interference. Two newly synthesized α-cyanocinnamic acid derivatives are reported here; (E)-2-cyano-3-(naphthalen-2-yl)acrylic acid (NpCCA) and (2E)-3-(anthracen-9-yl)-2-cyanoprop-2enoic acid (AnCCA). Along with the commonly used α-cyano-4-hydroxycinnamic acid (CHCA), and the recently developed 4-chloro-α-cyanocinnamic acid (Cl-CCA) matrices, these constitute a chemically similar series of matrices covering a range of molecular weights, and with correspondingly differing ranges of spectral interference. Their performance was compared by measuring the signal-to-noise ratios (S/N) of 47 analytes, mostly pharmaceuticals, with the different matrices using the selected reaction monitoring (SRM) mode on a triple quadrupole instrument equipped with a vacuum MALDI source. AnCCA, NpCCA and Cl-CCA were found to offer better signal-to-noise ratios in SRM mode than CHCA, but Cl-CCA yielded the best results for 60% of the compounds tested. To better understand the relative performance of this matrix series, the proton affinities (PAs) were measured using the kinetic method. Their relative values were: AnCCA > CHCA > NpCCA > Cl-CCA. This ordering is consistent with the performance data. The synthesis of the new matrices is straightforward and they provide (1) tunability of matrix background interfering ions and (2) enhanced analyte response for certain classes of compounds. Copyright © 2011 John Wiley & Sons, Ltd.

Public understanding of solar radiation management

International Nuclear Information System (INIS)

Mercer, A M; Keith, D W; Sharp, J D

2011-01-01

We report the results of the first large-scale international survey of public perception of geoengineering and solar radiation management (SRM). Our sample of 3105 individuals in the United States, Canada and the United Kingdom was recruited by survey firms that administer internet surveys to nationally representative population samples. Measured familiarity was higher than expected, with 8% and 45% of the population correctly defining the terms geoengineering and climate engineering respectively. There was strong support for allowing the study of SRM. Support decreased and uncertainty rose as subjects were asked about their support for using SRM immediately, or to stop a climate emergency. Support for SRM is associated with optimism about scientific research, a valuing of SRM's benefits and a stronger belief that SRM is natural, while opposition is associated with an attitude that nature should not be manipulated in this way. The potential risks of SRM are important drivers of public perception with the most salient being damage to the ozone layer and unknown risks. SRM is a new technology and public opinions are just forming; thus all reported results are sensitive to changes in framing, future information on risks and benefits, and changes to context.

Amorphization reaction in thin films of elemental Cu and Y

Science.gov (United States)

Johnson, R. W.; Ahn, C. C.; Ratner, E. R.

1989-10-01

Compositionally modulated thin films of Cu and Y were prepared in an ultrahigh-vacuum dc ion-beam deposition chamber. The amorphization reaction was monitored by in situ x-ray-diffraction measurements. Growth of amorphous Cu1-xYx is observed at room temperature with the initial formation of a Cu-rich amorphous phase. Further annealing in the presence of unreacted Y leads to Y enrichment of the amorphous phase. Growth of crystalline CuY is observed for T=469 K. Transmission-electron-microscopy measurements provide real-space imaging of the amorphous interlayer and growth morphology. Models are developed, incorporating metastable interfacial and bulk free-energy diagrams, for the early stage of the amorphization reaction.

Sensor Deployment for Air Pollution Monitoring Using Public Transportation System

OpenAIRE

Yu, James J. Q.; Li, Victor O. K.; Lam, Albert Y. S.

2015-01-01

Air pollution monitoring is a very popular research topic and many monitoring systems have been developed. In this paper, we formulate the Bus Sensor Deployment Problem (BSDP) to select the bus routes on which sensors are deployed, and we use Chemical Reaction Optimization (CRO) to solve BSDP. CRO is a recently proposed metaheuristic designed to solve a wide range of optimization problems. Using the real world data, namely Hong Kong Island bus route data, we perform a series of simulations an...

Share Price Reactions to CEO Resignations and Large Shareholder Monitoring in Listed French Companies

NARCIS (Netherlands)

Dherment-Ferere, I.; Renneboog, L.D.R.

2000-01-01

This study has analysed the share price reactions to changes in top management.A distinction was made among different types of CEO turnover: forced resignation, voluntary departures and age-related retirements.The announcement of a forced CEO resignation is hailed favourably by the market with a

Status of radiation detector and neutron monitor technology

CERN Document Server

Kim, Y K; Ha, J H; Han, S H; Hong, S B; Hwang, I K; Lee, W G; Moon, B S; Park, S H; Song, M H

2002-01-01

In this report, we describe the current states of the radiation detection technology, detectors for industrial application, and neutron monitors. We also survey the new technologies being applied to this field. The method to detect radiation is the measurement of the observable secondary effect from the interaction between incident radiation and detector material, such as ionization, excitation, fluorescence, and chemical reaction. The radiation detectors can be categorized into gas detectors, scintillation detectors, and semiconductor detectors according to major effects and main applications. This report contains the current status and operational principles of these detectors. The application fields of radiation detectors are industrial measurement system, in-core neutron monitor, medical radiation diagnostic device, nondestructive inspection device, environmental radiation monitoring, cosmic-ray measurement, security system, fundamental science experiment, and radiation measurement standardization. The st...

Methylene blue as a lignin surrogate in manganese peroxidase reaction systems.

Science.gov (United States)

Goby, Jeffrey D; Penner, Michael H; Lajoie, Curtis A; Kelly, Christine J

2017-11-15

Manganese peroxidase (MnP) is associated with lignin degradation and is thus relevant to lignocellulosic-utilization technologies. Technological applications require reaction mixture optimization. A surrogate substrate can facilitate this if its susceptibility to degradation is easily monitored and mirrors that of lignin. The dye methylene blue (MB) was evaluated in these respects as a surrogate substrate by testing its reactivity in reaction mixtures containing relevant redox mediators (dicarboxylic acids, fatty acids). Relative rates of MB degradation were compared to available literature reports of lignin degradation under similar conditions, and suggest that MB can be a useful lignin surrogate in MnP systems. Copyright © 2017 Elsevier Inc. All rights reserved.

Application of the k{sub 0}-INAA method for analysis of biological samples at the pneumatic station of the IEA-R1 nuclear research reactor

Energy Technology Data Exchange (ETDEWEB)

Puerta, Daniel C.; Figueiredo, Ana Maria G.; Semmler, Renato, E-mail: dcpuerta@hotmail.com, E-mail: anamaria@ipen.br, E-mail: rsemmler@ipen.br [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Jacimovic, Radojko, E-mail: radojko.jacimovic@ijs.si [Jozef Stefan Institute (JSI), Ljubljana, LJU (Slovenia). Department of Environmental Sciences

2013-07-01

As part of the process of implementation of the k{sub 0}-INAA standardization method at the Neutron Activation Laboratory (LAN-IPEN), Sao Paulo, Brazil, this study presents the results obtained for the analysis of short and medium-lived nuclides in biological samples by k{sub 0}-INAA using the program k{sub 0}-IAEA, provided by the International Atomic Energy Agency (IAEA). The elements Al, Ba, Br, Na, K, Mn, Mg, Sr and V were determined with respect to gold ({sup 197}Au) using the pneumatic station facility of the IEA-R1 4.5 MW swimming pool nuclear research reactor, Sao Paulo. Characterization of the pneumatic station was carried out by using the 'bare triple-monitor' method with {sup 197}Au-{sup 96}Zr-{sup 94}Zr. The Certified Reference Material IRMM-530R Al-0.1%Au alloy and high purity zirconium comparators were used. The efficiency curves of the gamma-ray spectrometer used were determined by measuring calibrated radioactive sources at the usually utilized counting geometries. The method was validated by analyzing the reference materials NIST SRM 1547 Peach Leaves, INCT-MPH-2 Mixed Polish Herbs and NIST SRM 1573a Tomato Leaves. The concentration results obtained agreed with certified, reference and recommended values, showing relative errors (bias, %) less than 30% for most elements. The Coefficients of Variation were below 20%, showing a good reproducibility of the results. The E{sub n}-number showed that all results, except Na in NIST SRM 1547 and NIST SRM 1573a and Al in INCT-MPH-2, were within 95% confidence interval. (author)

Real-time monitoring of enzyme-free strand displacement cascades by colorimetric assays

Science.gov (United States)

Duan, Ruixue; Wang, Boya; Hong, Fan; Zhang, Tianchi; Jia, Yongmei; Huang, Jiayu; Hakeem, Abdul; Liu, Nannan; Lou, Xiaoding; Xia, Fan

2015-03-01

The enzyme-free toehold-mediated strand displacement reaction has shown potential for building programmable DNA circuits, biosensors, molecular machines and chemical reaction networks. Here we report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade. During the process the assembled gold nanoparticles can be separated, resulting in a color change of the solution. This assay can also be applied in complex mixtures, fetal bovine serum, and to detect single-base mismatches. These results suggest that this method could be of general utility to monitor more complex enzyme-free strand displacement reaction-based programmable systems or for further low-cost diagnostic applications.The enzyme-free toehold-mediated strand displacement reaction has shown potential for building programmable DNA circuits, biosensors, molecular machines and chemical reaction networks. Here we report a simple colorimetric method using gold nanoparticles as signal generators for the real-time detection of the product of the strand displacement cascade. During the process the assembled gold nanoparticles can be separated, resulting in a color change of the solution. This assay can also be applied in complex mixtures, fetal bovine serum, and to detect single-base mismatches. These results suggest that this method could be of general utility to monitor more complex enzyme-free strand displacement reaction-based programmable systems or for further low-cost diagnostic applications. Electronic supplementary information (ESI) available: Experimental procedures and analytical data are provided. See DOI: 10.1039/c5nr00697j

Nucleophilic Fluorination Reactions in Novel Reaction Media for 18F-Fluorine Labeling Method

International Nuclear Information System (INIS)

Kim, Dong Wook; Jeong, Hwan Jeong; Lim, Seok Tae; Sohn, Myung Hee

2009-01-01

Noninvasive imaging of molecular and biological processes in living subjects with positron emission tomography (PET) provides exciting opportunities to monitor metabolism and detect diseases in humans. Measuring these processes with PET requires the preparation of specific molecular imaging probes labeled with 18F-fluorine. In this review we describe recent methods and novel trends for the introduction of 18 F-fluorine into molecules which in turn are intended to serve as imaging agents for PET study. Nucleophilic 18 F-fluorination of some halo- and mesyloxyalkanes to the corresponding 18 F-fluoroalkanes with 18 F-fluoride obtained from an 18 O(p,n) 18 F reaction, using novel reaction media system such as an ionic liquidor tert-alcohol, has been studied as a new method for 18 F-fluorine labeling. Ionic liquid method is rapid and particularly convenient because 18 F-fluoride in H 2 O can be added directly to the reaction media, obviating the careful drying that is typically required for currently used radiofluorination methods. The nonpolar protic tert-alcohol enhances the nucleophilicity of the fluoride ion dramatically in the absence of any kind of catalyst, greatly increasing the rate of the nucleophilic fluorination and reducing formation of byproducts compared with conventional methods using dipolar aprotic solvents. The great efficacy of this method is a particular advantage in labeling radiopharmaceuticals with 18 F-fluorine for PET imaging, and it is illustrated by the synthesis of 18 F-fluoride radiolabeled molecular imaging probes, such as 18 F-FDG, 18 F-FLT, 18 F-FP-CIT, and 18 F-FMISO, in high yield and purity and in shorter times compared to conventional syntheses

Simultaneous quantification of tafetinib (SIM010603), a novel potent inhibitor of receptor tyrosine kinase, and its major metabolite in dog plasma by HPLC-ESI/MS/MS and its application to a pharmacokinetic study.

Science.gov (United States)

Shao, Feng; Zhu, Tian; Tang, Feng; Liu, Xin

2013-01-01

This study presents a high-performance liquid chromatography-electrospray ionization-tandem mass spectrometry (HPLC-ESI/MS/MS) technique for the simultaneous determination of tafetinib (SIM010603) and its main metabolite (M1) in dog plasma by using Prazosin hydrochloric acid as the internal standard (IS). Both compounds were extracted from dog plasma with ethyl acetate and were separated by HPLC on a reversed phase C₁₈ column with a mobile phase of 10 mM ammonium acetate buffer containing 0.1% formic acid-acetonitrile (40:60, v/v) at a flow rate of 0.2 mL/min. For quantification, the triple-quadruple MS was used in selected reaction monitoring (SRM) mode. The monitored transitions were m/z 425.3 → 309.2 for tafetinib, m/z 397.2 → 309.2 for M1 and m/z 384.2 → 247.1 for IS. The developed method had a short run time of 4 min and good linearity was observed over a wide range of 1-1000 ng/mL for the two compounds. The method was successfully applied in the pharmacokinetic study of tafetinib and M1 in dog. Copyright © 2013 Elsevier B.V. All rights reserved.

Compound to Extract to Formulation: a knowledge-transmitting approach for metabolites identification of Gegen-Qinlian Decoction, a traditional Chinese medicine formula

Science.gov (United States)

Qiao, Xue; Wang, Qi; Wang, Shuang; Miao, Wen-juan; Li, Yan-jiao; Xiang, Cheng; Guo, De-an; Ye, Min

2016-01-01

Herbal medicines usually contain a large group of chemical components, which may be transformed into more complex metabolites in vivo. In this study, we proposed a knowledge-transmitting strategy for metabolites identification of compound formulas. Gegen-Qinlian Decoction (GQD) is a classical formula in traditional Chinese medicine (TCM). It is widely used to treat diarrhea and diabetes in clinical practice. However, only tens of metabolites could be detected using conventional approaches. To comprehensively identify the metabolites of GQD, a “compound to extract to formulation” strategy was established in this study. The metabolic pathways of single representative constituents in GQD were studied, and the metabolic rules were transmitted to chemically similar compounds in herbal extracts. After screening diversified metabolites from herb extracts, the knowledge was summarized to identify the metabolites of GQD. Tandem mass spectrometry (MSn), fragment-based scan (NL, PRE), and selected reaction monitoring (SRM) were employed to identify, screen, and monitor the metabolites, respectively. Using this strategy, we detected 131 GQD metabolites (85 were newly generated) in rats biofluids. Among them, 112 metabolites could be detected when GQD was orally administered at a clinical dosage (12.5 g/kg). This strategy could be used for systematic metabolites identification of complex Chinese medicine formulas. PMID:27996040

Enzymatic conformational fluctuations along the reaction coordinate of cytidine deaminase

OpenAIRE

Noonan, Ryan C.; Carter, Charles W.; Bagdassarian, Carey K.

2002-01-01

Analysis of the crystal structures for cytidine deaminase complexed with substrate analog 3-deazacytidine, transition-state analog zebularine 3,4-hydrate, and product uridine establishes significant changes in the magnitude of atomic-scale fluctuations along the (approximate) reaction coordinate of this enzyme. Differences in fluctuations between the substrate analog complex, transition-state analog complex, and product complex are monitored via changes in corresponding crystallographic tempe...

Self-propagating high-temperature synthesis of La(Sr)Ga(Mg)O{sub 3-{delta}} for electrolyte of solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Ishikawa, Hiroyuki [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Sapporo 060-8628 (Japan); Enoki, Makiko [Department of Applied Chemistry, Faculty of Engineering, Kyusyu University, Fukuoka 812-8581 (Japan); Ishihara, Tatsumi [Department of Applied Chemistry, Faculty of Engineering, Kyusyu University, Fukuoka 812-8581 (Japan); Akiyama, Tomohiro [Center for Advanced Research of Energy Conversion Materials, Hokkaido University, Sapporo 060-8628 (Japan)]. E-mail: takiyama@eng.hokudai.ac.jp

2007-03-14

This paper describes self-propagating high-temperature synthesis (SHS) of an electrolyte for solid oxide fuel (SOFC), in comparison to a conventional solid-state reaction method (SRM). Doped-lanthanum gallate: La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub 3-{delta}} (LSGM9182) and LSGM9173 as the SOFC electrolyte, was prepared by the SHS and sintered at different temperatures, for measuring the electrical conductivity of the sintered LSGM and the power generating performance at 1073 K, in comparison to the SRM. In the SHS, the LSGM powders with smaller size were obtained and easily sintered at the 100 K-lower temperature, 1673 K, than in the SRM. Most significantly, the electrical conductivity of the sintered LSGM9182 was as high as 0.11 S cm{sup -1} and its maximum power density was a value of 245 mW cm{sup -2} in the cell configuration of Ni/LSGM9182 (0.501 mm in thickness)/Sm{sub 0.5}Sr{sub 0.5}CoO{sub 3}. The conclusion was that the proposed SHS-sintering method with many benefits of minimizing the energy requirement and the processing time in the production, easing temperature restriction for the sintering, and improving the electrolyte performance up to a conventional level is practicable for producing the LSGM-electrolyte of SOFC at an intermediate-temperature application.

Self-propagating high-temperature synthesis of La(Sr)Ga(Mg)O3-δ for electrolyte of solid oxide fuel cells

International Nuclear Information System (INIS)

Ishikawa, Hiroyuki; Enoki, Makiko; Ishihara, Tatsumi; Akiyama, Tomohiro

2007-01-01

This paper describes self-propagating high-temperature synthesis (SHS) of an electrolyte for solid oxide fuel (SOFC), in comparison to a conventional solid-state reaction method (SRM). Doped-lanthanum gallate: La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3-δ (LSGM9182) and LSGM9173 as the SOFC electrolyte, was prepared by the SHS and sintered at different temperatures, for measuring the electrical conductivity of the sintered LSGM and the power generating performance at 1073 K, in comparison to the SRM. In the SHS, the LSGM powders with smaller size were obtained and easily sintered at the 100 K-lower temperature, 1673 K, than in the SRM. Most significantly, the electrical conductivity of the sintered LSGM9182 was as high as 0.11 S cm -1 and its maximum power density was a value of 245 mW cm -2 in the cell configuration of Ni/LSGM9182 (0.501 mm in thickness)/Sm 0.5 Sr 0.5 CoO 3 . The conclusion was that the proposed SHS-sintering method with many benefits of minimizing the energy requirement and the processing time in the production, easing temperature restriction for the sintering, and improving the electrolyte performance up to a conventional level is practicable for producing the LSGM-electrolyte of SOFC at an intermediate-temperature application

Excitation functions of radionuclides produced by proton induced reactions on gadolinium targets

International Nuclear Information System (INIS)

Challana, M.B.; Comsana, M.N.H.; Moawadb, G.S.; Abou-Zeid, M.A.

2008-01-01

Cross section study for proton induced reaction on natural Gadolinium targets were performed. Excitation functions for the reactions n atGd(p,x) 152m+g , 154m,154g Tb from threshold up to E p = 18 MeV have been measured employing the stacked foil activation technique, and using high resolution HPGe gamma spectrometry. Utilizing the simultaneous measurement of the excitation function of n atCu(p,x) 62 Zn, n atCu(p,x) 63 Zn, and n atCu(p,x) 65 Zn as monitor reactions. The theoretical analysis of the excitation functions has been done employing both ALICE-91 and EMPIRE-II codes. In general, theoretical calculations agree well with the experimental data. A significant contribution of pre-equilibrium component has been observed at these energies

Supramolecular Systems and Chemical Reactions in Single-Molecule Break Junctions.

Science.gov (United States)

Li, Xiaohui; Hu, Duan; Tan, Zhibing; Bai, Jie; Xiao, Zongyuan; Yang, Yang; Shi, Jia; Hong, Wenjing

2017-04-01

The major challenges of molecular electronics are the understanding and manipulation of the electron transport through the single-molecule junction. With the single-molecule break junction techniques, including scanning tunneling microscope break junction technique and mechanically controllable break junction technique, the charge transport through various single-molecule and supramolecular junctions has been studied during the dynamic fabrication and continuous characterization of molecular junctions. This review starts from the charge transport characterization of supramolecular junctions through a variety of noncovalent interactions, such as hydrogen bond, π-π interaction, and electrostatic force. We further review the recent progress in constructing highly conductive molecular junctions via chemical reactions, the response of molecular junctions to external stimuli, as well as the application of break junction techniques in controlling and monitoring chemical reactions in situ. We suggest that beyond the measurement of single molecular conductance, the single-molecule break junction techniques provide a promising access to study molecular assembly and chemical reactions at the single-molecule scale.

Elemental analysis using instrumental neutron activation analysis and inductively coupled plasma atomic emission spectrometry: a comparative study

International Nuclear Information System (INIS)

Chung, Yong Sam; Choi, Kwang Soon; Moon, Jong Hwa; Kim, Sun Ha; Lim, Jong Myoung; Kim, Young Jin; Quraishi, Shamshad Begum

2003-05-01

Elemental analyses for certified reference materials were carried out using instrumental neutron activation analysis and inductively coupled plasma-atomic emission spectrometry. Five Certified Reference Materials (CRM) were selected for the study on comparative analysis of environmental samples. The CRM are Soil (NIST SRM 2709), Coal fly ash (NIST SRM 1633a), urban dust (NIST SRM 1649a) and air particulate on filter media (NIST SRM 2783 and human hair (GBW 09101)

Supersonic molecular beam experiments on surface chemical reactions.

Science.gov (United States)

Okada, Michio

2014-10-01

The interaction of a molecule and a surface is important in various fields, and in particular in complex systems like biomaterials and their related chemistry. However, the detailed understanding of the elementary steps in the surface chemistry, for example, stereodynamics, is still insufficient even for simple model systems. In this Personal Account, I review our recent studies of chemical reactions on single-crystalline Cu and Si surfaces induced by hyperthermal oxygen molecular beams and by oriented molecular beams, respectively. Studies of oxide formation on Cu induced by hyperthermal molecular beams demonstrate a significant role of the translational energy of the incident molecules. The use of hyperthermal molecular beams enables us to open up new chemical reaction paths specific for the hyperthermal energy region, and to develop new methods for the fabrication of thin films. On the other hand, oriented molecular beams also demonstrate the possibility of understanding surface chemical reactions in detail by varying the orientation of the incident molecules. The steric effects found on Si surfaces hint at new ways of material fabrication on Si surfaces. Controlling the initial conditions of incoming molecules is a powerful tool for finely monitoring the elementary step of the surface chemical reactions and creating new materials on surfaces. Copyright © 2014 The Chemical Society of Japan and Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Targeted Quantitation of Site-Specific Cysteine Oxidation in Endogenous Proteins Using a Differential Alkylation and Multiple Reaction Monitoring Mass Spectrometry Approach

Science.gov (United States)

Held, Jason M.; Danielson, Steven R.; Behring, Jessica B.; Atsriku, Christian; Britton, David J.; Puckett, Rachel L.; Schilling, Birgit; Campisi, Judith; Benz, Christopher C.; Gibson, Bradford W.

2010-01-01

Reactive oxygen species (ROS) are both physiological intermediates in cellular signaling and mediators of oxidative stress. The cysteine-specific redox-sensitivity of proteins can shed light on how ROS are regulated and function, but low sensitivity has limited quantification of the redox state of many fundamental cellular regulators in a cellular context. Here we describe a highly sensitive and reproducible oxidation analysis approach (OxMRM) that combines protein purification, differential alkylation with stable isotopes, and multiple reaction monitoring mass spectrometry that can be applied in a targeted manner to virtually any cysteine or protein. Using this approach, we quantified the site-specific cysteine oxidation status of endogenous p53 for the first time and found that Cys182 at the dimerization interface of the DNA binding domain is particularly susceptible to diamide oxidation intracellularly. OxMRM enables analysis of sulfinic and sulfonic acid oxidation levels, which we validate by assessing the oxidation of the catalytic Cys215 of protein tyrosine phosphatase-1B under numerous oxidant conditions. OxMRM also complements unbiased redox proteomics discovery studies as a verification tool through its high sensitivity, accuracy, precision, and throughput. PMID:20233844

Evolution of the Maillard Reaction in Glutamine or Arginine-Dextrinomaltose Model Systems

Directory of Open Access Journals (Sweden)

Silvia Pastoriza

2016-12-01

Full Text Available Enteral formulas are foods designed for medical uses to feed patients who are unable to eat normally. They are prepared by mixing proteins, amino acids, carbohydrates and fats and submitted to sterilization. During thermal treatment, the Maillard reaction takes place through the reaction of animo acids with reducing sugars. Thus, although glutamine and arginine are usually added to improve the nutritional value of enteral formulas, their final concentration may vary. Thus, in the present paper the early, intermediate, and advanced states of the Maillard reaction were studied in model systems by measuring loss of free amino acids through the decrease of fluorescence intensity with o-phtaldialdehyde (OPA, 5-Hydroximethylfurfural (HMF, furfural, glucosylisomaltol, fluorescence, and absorbance at 420 nm. The systems were prepared by mixing glutamine or arginine with dextrinomaltose (similar ingredients to those used in special enteral formula, and heated at 100 °C, 120 °C and 140 °C for 0 to 30 min. The recorded changes in the concentration of furanic compounds was only useful for longer heating times of high temperatures, while absorbance and fluorescence measurements were useful in all the assayed conditions. In addition, easiness and sensitivity of absorbance and fluorescence make them useful techniques that could be implemented as indicators for monitoring the manufacture of special enteral formulas. Glucosylisomaltol is a useful indicator to monitor the manufacture of glutamine-enriched enteral formulas.

Evolution of the Maillard Reaction in Glutamine or Arginine-Dextrinomaltose Model Systems.

Science.gov (United States)

Pastoriza, Silvia; Rufián-Henares, José Ángel; García-Villanova, Belén; Guerra-Hernández, Eduardo

2016-12-07

Enteral formulas are foods designed for medical uses to feed patients who are unable to eat normally. They are prepared by mixing proteins, amino acids, carbohydrates and fats and submitted to sterilization. During thermal treatment, the Maillard reaction takes place through the reaction of animo acids with reducing sugars. Thus, although glutamine and arginine are usually added to improve the nutritional value of enteral formulas, their final concentration may vary. Thus, in the present paper the early, intermediate, and advanced states of the Maillard reaction were studied in model systems by measuring loss of free amino acids through the decrease of fluorescence intensity with o -phtaldialdehyde (OPA), 5-Hydroximethylfurfural (HMF), furfural, glucosylisomaltol, fluorescence, and absorbance at 420 nm. The systems were prepared by mixing glutamine or arginine with dextrinomaltose (similar ingredients to those used in special enteral formula), and heated at 100 °C, 120 °C and 140 °C for 0 to 30 min. The recorded changes in the concentration of furanic compounds was only useful for longer heating times of high temperatures, while absorbance and fluorescence measurements were useful in all the assayed conditions. In addition, easiness and sensitivity of absorbance and fluorescence make them useful techniques that could be implemented as indicators for monitoring the manufacture of special enteral formulas. Glucosylisomaltol is a useful indicator to monitor the manufacture of glutamine-enriched enteral formulas.

Estimating the Global Agricultural Impact of Solar Radiation Management using Volcanic Eruptions as Natural Experiments

Science.gov (United States)

Proctor, J.; Hsiang, S. M.; Burney, J. A.; Burke, M.; Schlenker, W.

2017-12-01

Solar radiation management (SRM) is increasingly considered an option for managing global temperatures, yet the economic impacts of ameliorating climatic changes by scattering sunlight back to space remain largely unknown. Though SRM may increase crop yields by reducing heat stress, its impacts from concomitant changes in available sunlight have never been empirically estimated. Here we use the volcanic eruptions that inspired modern SRM proposals as natural experiments to provide the first estimates of how the stratospheric sulfate aerosols (SS) created by the eruptions of El Chichon and Pinatubo altered the quantity and quality of global sunlight, how those changes in sunlight impacted global crop yields, and the total effect that SS may have on yields in an SRM scenario when the climatic and sunlight effects are jointly considered. We find that the sunlight-mediated impact of SS on yields is negative for both C4 (maize) and C3 (soy, rice, wheat) crops. Applying our yield model to a geoengineering scenario using SS-based SRM from 2050-2069, we find that SRM damages due to scattering sunlight are roughly equal in magnitude to SRM benefits from cooling. This suggests that SRM - if deployed using SS similar to those emitted by the volcanic eruptions it seeks to mimic - would attenuate little of the damages from climate change to global agriculture on net. Our approach could be extended to study SRM impacts on other global systems, such as human health or ecosystem function.

FxLMS Method for Suppressing In-Wheel Switched Reluctance Motor Vertical Force Based on Vehicle Active Suspension System

Directory of Open Access Journals (Sweden)

Yan-yang Wang

2014-01-01

Full Text Available The vibration of SRM obtains less attention for in-wheel motor applications according to the present research works. In this paper, the vertical component of SRM unbalanced radial force, which is named as SRM vertical force, is taken into account in suspension performance for in-wheel motor driven electric vehicles (IWM-EV. The analysis results suggest that SRM vertical force has a great effect on suspension performance. The direct cause for this phenomenon is that SRM vertical force is directly exerted on the wheel, which will result in great variation in tyre dynamic load and the tyre will easily jump off the ground. Furthermore, the frequency of SRM vertical force is broad which covers the suspension resonance frequencies. So it is easy to arouse suspension resonance and greatly damage suspension performance. Aiming at the new problem, FxLMS (filtered-X least mean square controller is proposed to improve suspension performance. The FxLMS controller is based on active suspension system which can generate the controllable force to suppress the vibration caused by SRM vertical force. The conclusion shows that it is effective to take advantage of active suspensions to reduce the effect of SRM vertical force on suspension performance.

Absolute calibration of the Rh-103 (n, n') Rh-103m reaction rate

Energy Technology Data Exchange (ETDEWEB)

Taylor, W.H.; Murphy, M.F.; March, M.R. [Reactor Physics Division, Atomic Energy Establishment, Winfrith, Dorchester, Dorset (United Kingdom)

1979-05-15

The uncertainties in determining the absolute values of the Rh-103 (n, n') Rh-103m reaction rate (which is widely used as a neutron damage flux monitor) have been reduced to {approx}{+-}5%. This has been achieved with the use of a calibrated source of Pd-103-Rh-103m activity supplied by the I.A.E.A. Agreement to within 3% between measured and calculated values of the reaction rate (normalised to the U-238 fission rate) has been achieved. (author)

1 H NMR and sono chemistry: monitoration of elimination and isomerization reactions of diterpenes, catalysed by TFAA

International Nuclear Information System (INIS)

Uchoa, Daniel Esdras de Andrade; Silveira, Edilberto Rocha

1997-01-01

There are in the literature several papers dealing with the influence of ultrasound over chemical reactions [1-4]. According to Moon, S., the general mechanism of sonochemistry (the chemistry of sound and ultrasound) is not known, but it is generally agreed that the phenomenon of cavitation (formation and collapse of micro-bubbles) is responsible for its chemical effects. Although ultrasound has been known for more than 60 years its application to chemical reactions has not been investigated throughly. (author)

Development and Implementation of an Automatic Continuous Online Monitoring and Control Platform for Polymerization Reactions to Sharply Boost Energy and Resource Efficiency in Polymer Manufacturing

Energy Technology Data Exchange (ETDEWEB)

Reed, Wayne [Tulane Univ., New Orleans, LA (United States); Drenski, Michael [Tulane Univ., New Orleans, LA (United States); Romagnoli, Jose [Tulane Univ., New Orleans, LA (United States)

2017-10-16

The project goal was to create an energy saving paradigm shift in how polymers are manufactured in the 21st century. It used Automatic Continuous Online Monitoring of Polymerization reactions (ACOMP) integrated for the first time with automatic active control to create the innovative ‘ACOMP/Control Interface’, or ‘ACOMP/CI’. ACOMP/CI will begin the transformation from old, inefficient processes into highly evolved, energy and resource efficient ones. The ACOMP platform is broadly applicable to many types of reactions and processes throughout the vast polymer industry. The industry provides materials for sectors such as automotive, aerospace, oil recovery, agriculture, paints, resins, adhesives, pharmaceuticals and therapeutic proteins, optics, electronics, lightweight building materials, and many more. The U.S. chemical industry is one of the last major sectors in which the U.S. has top global stature. It consumes 24% of all U.S. manufacturing energy, produces over $800B of product annually, supports 25% of the U.S. GDP and employs over 6 million people. It is also a major source of GHG emissions. Polymers make up approximately 30% of this sector. It is estimated that annually 60 TBtu of energy could be saved and 3 million tons less of GHG emissions produced by optimizing production in the polyolefin manufacturing sector alone. The project scope included first time design and prototyping of an ACOMP/CI, creation of active reaction controllers, and demonstration of control capabilities on ideal, low concentration polymerization reactions. All these elements of the scope were met, including advances and findings not originally anticipated. Extensions to more complex reactions, beyond the reactor capabilities of the current project ACOMP/CI, such as polyolefins and other high pressure/high temperature reactions, are being proposed in Fall 2017 to CESMII, a DoE based NNMI. The initial proposal was for a three year funded project, but this was reduced to a two

GTA Beamloss-Monitor System

International Nuclear Information System (INIS)

Rose, C.R.; Fortgang, C.M.; Power, J.P.

1992-01-01

The GTA Beamless-Monitor System at Los Alamos National Laboratory has been designed to detect high-energy particle loss in the accelerator beamline and shut down the accelerator before any damage can occur. To do this, the Beamless-Monitor System measures the induced gamma radiation, from (p, γ) reactions, at 15 selected points along the beamline, converts this measured radiation to electrical signals integrates and compares them to preset limits, and, in the event of an over-limit condition causes the Fast-Protect System to shut down the entire accelerator. The system dynamic range exceeds 70 dB which will enable experimenters to use the Beamless-Monitor System to help steer the beam as well as provide signals for a Fast-Protect System. The system response time is less than 7 μs assuming a step-function, worst-case beam spill of 50 mA. The system resolution, based on the noise floor of the electronics is about 1.3 mRads/s. Production units have been built and meet the above specifications. The remainder of the system will be installed and tested later in 1992/1993 with the GTA accelerator. The ionization chamber sensitivity and response time are described in the paper

GTA beamloss-monitor system

International Nuclear Information System (INIS)

Rose, C.R.; Fortgang, C.M.; Power, J.P.

1992-01-01

The GTA Beamloss-Monitor System at Los Alamos National Laboratory has been designed to detect high-energy particle loss in the accelerator beamline and shut down the accelerator before any damage can occur. To do this, the Beamloss-Monitor System measures the induced gamma radiation, from (p,γ) reactions, at 15 selected points along the beamline, converts this measured radiation to electrical signals, integrates and compares them to preset limits, and, in the event of an over-limit condition causes the Fast-Protect System to shut down the entire accelerator. The system dynamic range exceeds 70 dB which will enable experimenters to use the Beamloss-Monitor System to help steer the beam as well as provide signals for a Fast-Protect System. The system response time is less than 7 μs assuming a step-function, worst-case beam spill of 50 mA. The system resolution, based on the noise floor of the electronics, is about 1.3 mRads/s. Production units have been built and meet the above specifications. The remainder of the system will be installed and tested later in 1992/93 with the GTA accelerator. The ionization chamber sensitivity and response time are described in the paper. (Author) 4 figs., ref

Breath acetone monitoring by portable Si:WO3 gas sensors

International Nuclear Information System (INIS)

Righettoni, Marco; Tricoli, Antonio; Gass, Samuel; Schmid, Alex; Amann, Anton; Pratsinis, Sotiris E.

2012-01-01

Highlights: ► Portable sensors were developed and tested for monitoring acetone in the human breath. ► Acetone concentrations down to 20 ppb were measured with short response times ( 3 nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (∼20 ppb) with short response (10–15 s) and recovery times (35–70 s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80–90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques.

Measurement of cross-sections of yttrium (n,xn) threshold reactions by means of gamma spectroscopy

CERN Document Server

Chudoba, Petr; Wagner, V; Vrzalova, J; Svoboda, O; Majerle, M; Stefanik, M; Suchopar, M; Kugler, A; Bielewicz, M; Strugalska-Gola, E; Szuta, M; Hervas, D; Herman, T; Geier, B

2014-01-01

Neutron activation and gamma spectrometry are usable also f or the determination of cross-sections of different neutron reactions. We have studied the cross-sections of yttrium (n, x n) threshold reactions using quasi-monoenergetic neutron source based on the reaction on 7 Li target at Nuclear Physics Institute of ASCR in Rez. Yttrium (n, x n) threshold reactions are suitable candidates for fast neutron field measurement by activation detectors. Fast neutron field monitoring is necessary already today at a wide range of accelerator facilities and will gain on importance in future fast reactors of generation IV, accelerator transmutation systems or fusion reactors. The knowledge of the cross-sections is crucial for such purpose. Unfortunately, the cross-section is sufficiently known only for 89 Y(n,2n) 88 Y reaction. For higher orders of reactions there are almost no experimental data. Special attention was paid to t he 89 Y(n,3n) 87 Y reaction. The cross-sections of both 89 Y(n,2n) 88 Y and 89 Y(n,3n) 87 Y re...

Chronic myelogenous leukemia: molecular monitoring in clinical practice

Directory of Open Access Journals (Sweden)

N. R. Ryabchikova

2013-01-01

Full Text Available Use of tyrosine kinase inhibitor imatinib has led to significant progress in chronic myeloid leukemia (CML treatment. To date, genetic monitoring is a mandatory attribute of therapy with tyrosine kinase inhibitors. The purpose of this study was to access the imatinib therapy efficacy in CML patients using complete molecular genetic monitoring by standard cytogenetics, realtime polymerase chain reaction and mutational analysis. Correlation between cytogenetic and molecular response was shown. Heterogeneity of molecular response in each patient group was revealed by expression of BCR-ABL. Kinase domain mutations were detected in 32 % of CML patients resistant to imatinib.

Air Quality Monitoring Programme

DEFF Research Database (Denmark)

Kemp, K.; Palmgren, F.

The air quality in Danish cities has been monitored continuously since 1982 within the Danish Air Quality (LMP) network. The aim has been to follow the concentration levels of toxic pollutants in the urban atmosphere and to provide the necessary knowledge to assess the trends, to perform source...... apportionment, and to evaluate the chemical reactions and the dispersion of the pollutants in the atmosphere. In 2002 the air quality was measured in four Danish cities and at two background sites. NO2 and PM10 were at several stations found in concentrations above the new EU limit values, which the Member...

Determination of hydrazine in drinking water: Development and multivariate optimization of a rapid and simple solid phase microextraction-gas chromatography-triple quadrupole mass spectrometry protocol.

Science.gov (United States)

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

2014-07-04

In this work, the capabilities of solid phase microextraction were exploited in a fully optimized SPME-GC-QqQ-MS analytical approach for hydrazine assay. A rapid and easy method was obtained by a simple derivatization reaction with propyl chloroformate and pyridine carried out directly in water samples, followed by automated SPME analysis in the same vial without further sample handling. The affinity of the different derivatized compounds obtained towards five commercially available SPME coatings was evaluated, in order to achieve the best extraction efficiency. GC analyses were carried out using a GC-QqQ-MS instrument in selected reaction monitoring (SRM) acquisition mode which has allowed the achievement of high specificity by selecting appropriate precursor-product ion couples improving the capability in analyte identification. The multivariate approach of experimental design was crucial in order to optimize derivatization reaction, SPME process and tandem mass spectrometry parameters. Accuracy of the proposed protocol, tested at 60, 200 and 800 ng L(-1), provided satisfactory values (114.2%, 83.6% and 98.6%, respectively), whereas precision (RSD%) at the same concentration levels were of 10.9%, 7.9% and 7.7% respectively. Limit of detection and quantification of 4.4 and 8.3 ng L(-1) were obtained. The reliable application of the proposed protocol to real drinking water samples confirmed its capability to be used as analytical tool for routine analyses. Copyright © 2014 Elsevier B.V. All rights reserved.

Reaction time for trimolecular reactions in compartment-based reaction-diffusion models

Science.gov (United States)

Li, Fei; Chen, Minghan; Erban, Radek; Cao, Yang

2018-05-01

Trimolecular reaction models are investigated in the compartment-based (lattice-based) framework for stochastic reaction-diffusion modeling. The formulae for the first collision time and the mean reaction time are derived for the case where three molecules are present in the solution under periodic boundary conditions. For the case of reflecting boundary conditions, similar formulae are obtained using a computer-assisted approach. The accuracy of these formulae is further verified through comparison with numerical results. The presented derivation is based on the first passage time analysis of Montroll [J. Math. Phys. 10, 753 (1969)]. Montroll's results for two-dimensional lattice-based random walks are adapted and applied to compartment-based models of trimolecular reactions, which are studied in one-dimensional or pseudo one-dimensional domains.

Real-time studies of chemical reactions in lab-on-a-chip devices

NARCIS (Netherlands)

Brivio, M.

2005-01-01

The realization of a lab-on-a-chip system in which chemical reactions are carried out in a continuous flow mode and monitored on-line by a suitable analytical technique is the main topic of this thesis. Two types of a lab-on-a-chip were realized, both using mass spectrometry (MS) as the on-line

Surface Acoustic Wave (SAW Resonators for Monitoring Conditioning Film Formation

Directory of Open Access Journals (Sweden)

Siegfried Hohmann

2015-05-01

Full Text Available We propose surface acoustic wave (SAW resonators as a complementary tool for conditioning film monitoring. Conditioning films are formed by adsorption of inorganic and organic substances on a substrate the moment this substrate comes into contact with a liquid phase. In the case of implant insertion, for instance, initial protein adsorption is required to start wound healing, but it will also trigger immune reactions leading to inflammatory responses. The control of the initial protein adsorption would allow to promote the healing process and to suppress adverse immune reactions. Methods to investigate these adsorption processes are available, but it remains difficult to translate measurement results into actual protein binding events. Biosensor transducers allow user-friendly investigation of protein adsorption on different surfaces. The combination of several transduction principles leads to complementary results, allowing a more comprehensive characterization of the adsorbing layer. We introduce SAW resonators as a novel complementary tool for time-resolved conditioning film monitoring. SAW resonators were coated with polymers. The adsorption of the plasma proteins human serum albumin (HSA and fibrinogen onto the polymer-coated surfaces were monitored. Frequency results were compared with quartz crystal microbalance (QCM sensor measurements, which confirmed the suitability of the SAW resonators for this application.

Breath acetone monitoring by portable Si:WO3 gas sensors

Science.gov (United States)

Righettoni, Marco; Tricoli, Antonio; Gass, Samuel; Schmid, Alex; Amann, Anton; Pratsinis, Sotiris E.

2013-01-01

Breath analysis has the potential for early stage detection and monitoring of illnesses to drastically reduce the corresponding medical diagnostic costs and improve the quality of life of patients suffering from chronic illnesses. In particular, the detection of acetone in the human breath is promising for non-invasive diagnosis and painless monitoring of diabetes (no finger pricking). Here, a portable acetone sensor consisting of flame-deposited and in situ annealed, Si-doped epsilon-WO3 nanostructured films was developed. The chamber volume was miniaturized while reaction-limited and transport-limited gas flow rates were identified and sensing temperatures were optimized resulting in a low detection limit of acetone (~20 ppb) with short response (10–15 s) and recovery times (35–70 s). Furthermore, the sensor signal (response) was robust against variations of the exhaled breath flow rate facilitating application of these sensors at realistic relative humidities (80–90%) as in the human breath. The acetone content in the breath of test persons was monitored continuously and compared to that of state-of-the-art proton transfer reaction mass spectrometry (PTR-MS). Such portable devices can accurately track breath acetone concentration to become an alternative to more elaborate breath analysis techniques. PMID:22790702

Excitation functions of alpha particle induced reactions on {sup nat}Ti up to 40 MeV

Energy Technology Data Exchange (ETDEWEB)

Uddin, M.S., E-mail: md.shuzauddin@yahoo.com [Tandem Accelerator Facilities, Institute of Nuclear Science and Technology, Atomic Energy Research Establishment, Savar, Dhaka (Bangladesh); Scholten, B. [Institut für Neurowissenschaften und Medizin, INM-5:Nuklearchemie, Forschungszentrum Jülich, D-52425 Jülich (Germany)

2016-08-01

Excitation functions of the reactions {sup nat}Ti(α,x){sup 48}Cr, {sup nat}Ti(α,x){sup 48}V and {sup nat}Ti(α,x){sup 46,48}Sc were determined by the stacked-foil activation technique up to 40 MeV. The radioactivities produced in the {sup nat}Ti target were measured by γ-ray spectrometry using HPGe detector. The reaction {sup nat}Ti(α,x){sup 51}Cr was used to determine the beam parameters. New experimental values for the above reactions have been obtained. An intercomparison of our data with the available literature values has been done. The cross section results obtained in this work could be useful in defining new monitor reactions, radiation safety and isotope production.

Optical monitoring of gases with cholesteric liquid crystals.

Science.gov (United States)

Han, Yang; Pacheco, Katherine; Bastiaansen, Cees W M; Broer, Dirk J; Sijbesma, Rint P

2010-03-10

A new approach to optical monitors for gases is introduced using cholesteric liquid crystals doped with reactive chiral compounds. The approach is based on cholesteric pitch length changes caused by a change in helical twisting power (HTP) of the chiral dopants upon reaction with the analyte. The concept is demonstrated for monitoring carbon dioxide via reversible carbamate formation and for oxygen using the irreversible oxidation of a chiral dithiol to a disulfide. Monitoring of CO(2) was achieved by doping a commercial cholesteric liquid crystalline mixture (E7) with 1.6% mol of the 1:1 complex of an optically pure diamine with a TADDOL derivative. Upon exposure to carbon dioxide, the reflection band of a thin film of the mixture shifted from 637 to 495 nm as a consequence of dissociation of the complex after carbamate formation of the diamine. An O(2) monitor was obtained by doping E7 with a chiral binaphthyl dithiol derivative and a nonresponsive codopant. The reflection band of the oxygen monitor film changed from 542 to 600 nm, due to the conformational change accompanying oxidation of the dithiol to disulfide. These monitoring mechanisms hold promise for application in smart packaging, where carbon dioxide and oxygen are of special interest because of their roles in food preservation.

Simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma using high performance liquid chromatography coupled with tandem mass spectrometric detection: application to a bioequivalence study.

Science.gov (United States)

Hu, Ziyan; Zou, Qiaogen; Tian, Jixin; Sun, Lili; Zhang, Zunjian

2011-12-15

A rapid and sensitive method based on liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the simultaneous determination of codeine, ephedrine, guaiphenesin and chlorpheniramine in beagle dog plasma has been developed and validated. Following liquid-liquid extraction, the analytes were separated on a reversed-phase C(18) column (150 mm × 2.0 mm, 3 μm) using formic acid:10 mM ammonium acetate:methanol (0.2:62:38, v/v/v) as mobile phase at a flow rate of 0.2 mL/min and analyzed by a triple-quadrupole mass spectrometer in the selected reaction monitoring (SRM) mode. The method was linear for all analytes over the following concentration (ng/mL) ranges: codeine 0.08-16; ephedrine 0.8-160; guaiphenesin 80-16,000; chlorpheniramine 0.2-40. Acceptable precision and accuracy were obtained for concentrations over the standard curve range. It is the first time that the validated HPLC-MS/MS method was successfully applied to a bioequivalence study in 6 healthy beagle dogs. Copyright © 2011 Elsevier B.V. All rights reserved.

Determination of cyclovirobuxine D in human plasma by liquid chromatography tandem mass spectrometry and application in a pharmacokinetic study

Directory of Open Access Journals (Sweden)

Ling-li Mu

2011-10-01

Full Text Available A sensitive and reliable method based on liquid chromatography tandem mass spectrometry (LC–MS/MS for the quantitation of cyclovirobuxine D in human plasma has been developed and validated. Sample preparation by solid phase extraction was followed by separation on a CN column with a mobile phase of methanol–water (95:5, v/v containing 0.2% formic acid. Mass spectrometric detection in the positive ion mode was carried out by selected reaction monitoring (SRM of the transitions at m/z 403.0→372.0 for cyclovirobuxine D and m/z 325.0→234.0 for citalopram (internal standard. The method was linear in the range 10–200 ng/L with LLOQ of 10 ng/L, recovery >85%, and no significant matrix effects. Intra- and inter-day precisions were all <9% with accuracies of 94.0–104.8%. The method was successfully applied to a pharmacokinetic study involving a single oral administration of a 2 mg cyclovirobuxine D tablet to twenty-two healthy Chinese volunteers.

Spatio-temporal detection of the Thiomonas population and the Thiomonas arsenite oxidase involved in natural arsenite attenuation processes in the Carnoulès Acid Mine Drainage

Directory of Open Access Journals (Sweden)

Agnès eHovasse

2016-02-01

Full Text Available The acid mine drainage (AMD impacted creek of the Carnoulès mine (Southern France is characterized by acid waters with a high heavy metal content. The microbial community inhabiting this AMD was extensively studied using isolation, metagenomic and metaproteomic methods, and the results showed that a natural arsenic (and iron attenuation process involving the arsenite oxidase activity of several Thiomonas strains occurs at this site. A sensitive quantitative Selected Reaction Monitoring (SRM-based proteomic approach was developed for detecting and quantifying the two subunits of the arsenite oxidase and RpoA of two different Thiomonas groups. Using this approach combined with 16S rRNA gene sequence analysis based on pyrosequencing and FISH, it was established here for the first time that these Thiomonas strains are ubiquitously present in minor proportions in this AMD and that they express the key enzymes involved in natural remediation processes at various locations and time points. In addition to these findings, this study also confirms that targeted proteomics applied at the community level can be used to detect weakly abundant proteins in situ.

Reaction of hydroxyl radicals with ammonia in liquid water at elevated temperatures

DEFF Research Database (Denmark)

Hickel, B.; Sehested, K.

1992-01-01

The reaction of hydroxyl radical with ammonia in aqueous solutions has been studied by pulse radiolysis in the temperature range 20-200-degrees-C. The rate constant of the reaction was determined by monitoring the decay of the OH radical absorption at 260 nm for different concentrations of ammonia....... At room temperature the rate constant is (9.7 +/- 1) x 10(7) dm3 mol-1 s-1. In the whole range of temperatures the Tate constant follows Arrhenius law with an activation energy of (5.7 +/- 1) kJ mol-1. The protective effect of dissolved hydrogen on the radiolytic decomposition of ammon a is discussed....

Raman spectroscopic approach to monitor the in vitro cyclization of creatine → creatinine

Science.gov (United States)

Gangopadhyay, Debraj; Sharma, Poornima; Singh, Sachin Kumar; Singh, Pushkar; Tarcea, Nicolae; Deckert, Volker; Popp, Jürgen; Singh, Ranjan K.

2015-01-01

The creatine → creatinine cyclization, an important metabolic phenomenon has been initiated in vitro at acidic pH and studied through Raman spectroscopic and DFT approach. The equilibrium composition of neutral, zwitterionic and protonated microspecies of creatine has been monitored with time as the reaction proceeds. Time series Raman spectra show clear signature of creatinine formation at pH 3 after ∼240 min at room temperature and reaction is faster at higher temperature. The spectra at pH 1 and pH 5 do not show such signature up to 270 min implying faster reaction rate at pH 3.

An Internal Thermal Environment Model of an Aluminized Solid Rocket Motor with Experimental Validation

Science.gov (United States)

Martin, Heath T.

2015-01-01

Due to the severity of the internal solid rocket motor (SRM) environment, very few direct measurements of that environment exist; therefore, the appearance of such data provides a unique opportunity to assess current thermal/fluid modeling capabilities. As part of a previous study of SRM internal insulation performance, the internal thermal environment of a laboratory-scale SRM featuring aluminized propellant was characterized with two types of custom heat-flux calorimeters: one that measured the total heat flux to a graphite slab within the SRM chamber and another that measured the thermal radiation flux. Therefore, in the current study, a thermal/fluid model of this lab-scale SRM was constructed using ANSYS Fluent to predict not only the flow field structure within the SRM and the convective heat transfer to the interior walls, but also the resulting dispersion of alumina droplets and the radiative heat transfer to the interior walls. The dispersion of alumina droplets within the SRM chamber was determined by employing the Lagrangian discrete phase model that was fully coupled to the Eulerian gas-phase flow. The P1-approximation was engaged to model the radiative heat transfer through the SRM chamber where the radiative contributions of the gas phase were ignored and the aggregate radiative properties of the alumina dispersion were computed from the radiative properties of its individual constituent droplets, which were sourced from literature. The convective and radiative heat fluxes computed from the thermal/fluid model were then compared with those measured in the lab-scale SRM test firings and the modeling approach evaluated.

Enhanced monitoring of hazardous waste site remediation: Electrical conductivity tomography and citizen monitoring of remediation through the EPA's community advisory group program

Science.gov (United States)

Hort, Ryan D.

In situ chemical oxidation using permanganate has become a common method for degrading trichloroethene (TCE) in contaminated aquifers. Its effectiveness, however, is dependent upon contact between the oxidant and contaminant. Monitoring permanganate movement after injection is often hampered by aquifer heterogeneity and insufficient well coverage. Time lapse electrical conductivity tomography increases the spatial extent of monitoring beyond well locations. This technique can create two- or three-dimensional images of the electrical conductivity within the aquifer to monitor aquifer chemistry changes caused by permanganate injection and oxidation reactions. In-phase and quadrature electrical conductivity were measured in homogeneous aqueous and porous media samples to determine the effects of TCE and humate oxidation by permanganate on both measures of conductivity. Further effects of clean sand, 10% kaolinite (v/v), and 10% smectite (v/v) on both types of conductivity were studied as well. Finally, in-phase electrical conductivity was measured over time after injecting permanganate solution into two-dimensional tanks containing artificial groundwater with and without TCE to observe the movement of the permanganate plume and its interaction with TCE and to examine the effectiveness of time-lapse conductivity tomography for monitoring the plume's movement. In-phase electrical conductivity after oxidation reactions involving permanganate, TCE, and humate could be accurately modeled in homogeneous batch samples. Use of forward modeling of in-phase conductivity from permanganate concentrations may be useful for improving recovery of conductivity values during survey inversion, but further work is needed combining the chemistry modeling with solute transport models. Small pH-related quadrature conductivity decreases were observed after TCE oxidation, and large quadrature conductivity increases were observed as a result of sodium ion addition; however, quadrature

Investigations of chemical warfare agents and toxic industrial compounds with proton-transfer-reaction mass spectrometry for a real-time threat monitoring scenario.

Science.gov (United States)

Kassebacher, Thomas; Sulzer, Philipp; Jürschik, Simone; Hartungen, Eugen; Jordan, Alfons; Edtbauer, Achim; Feil, Stefan; Hanel, Gernot; Jaksch, Stefan; Märk, Lukas; Mayhew, Chris A; Märk, Tilmann D

2013-01-30

Security and protection against terrorist attacks are major issues in modern society. One especially challenging task is the monitoring and protection of air conditioning and heating systems of buildings against terrorist attacks with toxic chemicals. As existing technologies have low selectivity, long response times or insufficient sensitivity, there is a need for a novel approach such as we present here. We have analyzed various chemical warfare agents (CWAs) and/or toxic industrial compounds (TICs) and related compounds, namely phosgene, diphosgene, chloroacetone, chloroacetophenone, diisopropylaminoethanol, and triethyl phosphate, utilizing a high-resolution proton-transfer-reaction time-of-flight mass spectrometry (PTR-TOFMS) instrument with the objective of finding key product ions and their intensities, which will allow a low-resolution quadrupole mass spectrometry based PTR-MS system to be used with high confidence in the assignment of threat agents in the atmosphere. We obtained high accuracy PTR-TOFMS mass spectra of the six compounds under study at two different values for the reduced electric field in the drift tube (E/N). From these data we have compiled a table containing product ions, and isotopic and E/N ratios for highly selective threat compound detection with a compact and cost-effective quadrupole-based PTR-MS instrument. Furthermore, using chloroacetophenone (tear gas), we demonstrated that this instrument's response is highly linear in the concentration range of typical Acute Exposure Guideline Levels (AEGLs). On the basis of the presented results it is possible to develop a compact and cost-effective PTR-QMS instrument that monitors air supply systems and triggers an alarm as soon as the presence of a threat agent is detected. We hope that this real-time surveillance device will help to seriously improve safety and security in environments vulnerable to terrorist attacks with toxic chemicals. Copyright © 2012 John Wiley & Sons, Ltd.

Effect of known clad and pellet reactions on the GEC ESL design of dry vault store

International Nuclear Information System (INIS)

Wheeler, D.

1984-01-01

The more important clad and pellet reactions and their temperature dependence are briefly reviewed, followed by an outline of the economical GEC ESL interim spent fuel storage concept that highlights: The ability of the concept to reduce the temperature of the fuel to values where the clad and pellet reactions are minimal. The containment philosophy that enables any consequences of the reactions to be safely retained to ALARA principles. The maintenance of an air storage environment that can never be lost. The utilisation of passive, naturally induced cooling regimes. The ability to continuously monitor for long-term degradation, together with ease of inspection at any time during storage

Rapid and reversible impairments of short- and long-term social recognition memory are caused by acute isolation of adult rats via distinct mechanisms.

Science.gov (United States)

Shahar-Gold, Hadar; Gur, Rotem; Wagner, Shlomo

2013-01-01

Mammalian social organizations require the ability to recognize and remember individual conspecifics. This social recognition memory (SRM) can be examined in rodents using their innate tendency to investigate novel conspecifics more persistently than familiar ones. Here we used the SRM paradigm to examine the influence of housing conditions on the social memory of adult rats. We found that acute social isolation caused within few days a significant impairment in acquisition of short-term SRM of male and female rats. Moreover, SRM consolidation into long-term memory was blocked following only one day of social isolation. Both impairments were reversible, but with different time courses. Furthermore, only the impairment in SRM consolidation was reversed by systemic administration of arginine-vasopressin (AVP). In contrast to SRM, object recognition memory was not affected by social isolation. We conclude that acute social isolation rapidly induces reversible changes in the brain neuronal and molecular mechanisms underlying SRM, which hamper its acquisition and completely block its consolidation. These changes occur via distinct, AVP sensitive and insensitive mechanisms. Thus, acute social isolation of rats swiftly causes changes in their brain and interferes with their normal social behavior.

Rapid and reversible impairments of short- and long-term social recognition memory are caused by acute isolation of adult rats via distinct mechanisms.

Directory of Open Access Journals (Sweden)

Hadar Shahar-Gold

Full Text Available Mammalian social organizations require the ability to recognize and remember individual conspecifics. This social recognition memory (SRM can be examined in rodents using their innate tendency to investigate novel conspecifics more persistently than familiar ones. Here we used the SRM paradigm to examine the influence of housing conditions on the social memory of adult rats. We found that acute social isolation caused within few days a significant impairment in acquisition of short-term SRM of male and female rats. Moreover, SRM consolidation into long-term memory was blocked following only one day of social isolation. Both impairments were reversible, but with different time courses. Furthermore, only the impairment in SRM consolidation was reversed by systemic administration of arginine-vasopressin (AVP. In contrast to SRM, object recognition memory was not affected by social isolation. We conclude that acute social isolation rapidly induces reversible changes in the brain neuronal and molecular mechanisms underlying SRM, which hamper its acquisition and completely block its consolidation. These changes occur via distinct, AVP sensitive and insensitive mechanisms. Thus, acute social isolation of rats swiftly causes changes in their brain and interferes with their normal social behavior.

Multi-mycotoxin analysis of animal feed and animal-derived food using LC-MS/MS system with timed and highly selective reaction monitoring.

Science.gov (United States)

Zhao, Zhiyong; Liu, Na; Yang, Lingchen; Deng, Yifeng; Wang, Jianhua; Song, Suquan; Lin, Shanhai; Wu, Aibo; Zhou, Zhenlei; Hou, Jiafa

2015-09-01

Mycotoxins have the potential to enter the human food chain through carry-over of contaminants from feed into animal-derived products. The objective of the study was to develop a reliable and sensitive method for the analysis of 30 mycotoxins in animal feed and animal-derived food (meat, edible animal tissues, and milk) using liquid chromatography-tandem mass spectrometry (LC-MS/MS). In the study, three extraction procedures, as well as various cleanup procedures, were evaluated to select the most suitable sample preparation procedure for different sample matrices. In addition, timed and highly selective reaction monitoring on LC-MS/MS was used to filter out isobaric matrix interferences. The performance characteristics (linearity, sensitivity, recovery, precision, and specificity) of the method were determined according to Commission Decision 2002/657/EC and 401/2006/EC. The established method was successfully applied to screening of mycotoxins in animal feed and animal-derived food. The results indicated that mycotoxin contamination in feed directly influenced the presence of mycotoxin in animal-derived food. Graphical abstract Multi-mycotoxin analysis of animal feed and animal-derived food using LC-MS/MS.

Investigation of the use of Maillard reaction inhibitors for the production of patatin-carbohydrate conjugates.

Science.gov (United States)

Seo, Sooyoun; Karboune, Salwa

2014-12-17

Selected Maillard reaction inhibitors, including aminoguanidine, cysteine, pyridoxamine, and sodium bisulfite, were evaluated for their effect on the production of carbohydrate conjugated proteins with less cross-linking/browning. Patatin (PTT), a major potato protein, was glycated with galactose, xylose, galactooligosaccharides, xylooligosaccharides, galactan, and xylan under controlled conditions. The effectiveness of the inhibitors to control the glycation reaction was assessed by monitoring the glycation extent, the protein cross-linking, and the formation of dicarbonyl compounds. Sodium bisulfite was the most effective inhibitor for PTT-galactose and PTT-xylan reaction systems (reaction control ratios of 210.0 and 12.8). On the other hand, aminoguanidine and cysteine led to the highest reaction control ratios for the PTT-xylose/xylooligosaccharide (160.0 and 143.0) and PTT-galactooligosaccharides/galactan (663.0 and 71.0) reaction systems, respectively. The use of cysteine and aminoguanidine as inhibitors led to 1.7-99.4% decreases in the particle size distribution of the PTT conjugates and to 0.4-9.3% increases in their relative digestibility, per 5% blocked lysine.

A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.

Science.gov (United States)

Chai, Xin-Sheng; Zhong, Jin-Feng; Hu, Hui-Chao

2012-05-18

This paper describes a novel multiple-headspace extraction/gas chromatographic (MHE-GC) technique for monitoring monomer conversion during a polymerization reaction in a water-based emulsion environment. The polymerization reaction of methyl methacrylate (MMA) in an aqueous emulsion is used as an example. The reaction was performed in a closed headspace sample vial (as a mini-reactor), with pentane as a tracer. In situ monitoring of the vapor concentration of the tracer, employing a multiple headspace extraction (sampling) scheme, coupled to a GC, makes it possible to quantitatively follow the conversion of MMA during the early stages of polymerization. Data on the integrated amount of the tracer vapor released from the monomer droplet phase during the polymerization is described by a mathematic equation from which the monomer conversion can be calculated. The present method is simple, automated and economical, and provides an efficient tool in the investigation of the reaction kinetics and effects of the reaction conditions on the early stage of polymerization. Copyright © 2012 Elsevier B.V. All rights reserved.

Studies in heavy ion activation analysis Pt. 5

International Nuclear Information System (INIS)

Ojo, J.F.; Lass, B.D.; Schweikert, E.A.

1980-01-01

Nondestructive heavy ion activation analysis has been used to determine the carbon content in various NBS SRM steel samples with a 7.0 MeV 6 Li + beam. The reaction 12 C( 6 Li,αn) 13 N allows for carbon analysis with the only possible interference being beryllium, 9 Be( 6 Li,2n) 13 N. Under interference-free conditions, and employing a post-irradiation etch, the detection limit for carbon analysis in steel was 5 ppm. (author)

Using inductively coupled plasma-mass spectrometry for calibration transfer between environmental CRMs.

Science.gov (United States)

Turk, G C; Yu, L L; Salit, M L; Guthrie, W F

2001-06-01

Multielement analyses of environmental reference materials have been performed using existing certified reference materials (CRMs) as calibration standards for inductively coupled plasma-mass spectrometry. The analyses have been performed using a high-performance methodology that results in comparison measurement uncertainties that are significantly less than the uncertainties of the certified values of the calibration CRM. Consequently, the determined values have uncertainties that are very nearly equivalent to the uncertainties of the calibration CRM. Several uses of this calibration transfer are proposed, including, re-certification measurements of replacement CRMs, establishing traceability of one CRM to another, and demonstrating the equivalence of two CRMs. RM 8704, a river sediment, was analyzed using SRM 2704, Buffalo River Sediment, as the calibration standard. SRM 1632c, Trace Elements in Bituminous Coal, which is a replacement for SRM 1632b, was analyzed using SRM 1632b as the standard. SRM 1635, Trace Elements in Subbituminous Coal, was also analyzed using SRM 1632b as the standard.

On-line monitoring of Glucose and penicillin by sequential injection analysis

DEFF Research Database (Denmark)

Min, R.W.; Nielsen, Jens Bredal; Villadsen, John

1996-01-01

and a detector. The glucose analyzer is based on an enzymatic reaction using glucose oxidase, which converts glucose to glucono-lactone with formation of hydrogen peroxide and subsequent detection of H2O2 by a chemiluminescence reaction involving luminol. The penicillin analysis is based on formation......A sequential injection analysis (SIA) system has been developed for on-line monitoring of glucose and penicillin during cultivations of the filamentous fungus Penicillium chrysogenum. The SIA system consists of a peristaltic pump, an injection valve, two piston pumps, two multi-position valves...

Monitoring BTEX degradation by CSIA - chances and challenges

Science.gov (United States)

Vogt, Carsten; Dorer, Conrad; Kümmel, Steffen; Bombach, Petra; Fischer, Anko; Richnow, Hans Hermann

2014-05-01

Monitoring is crucial for evaluating the success of any geobiotechnological applications. Compound- specific stable isotope analysis (CSIA) has emerged as a key method for monitoring biogeochemical transformation processes. Isotope compositions of residual reactants may change during the first rate-limiting step in (bio)chemical reactions; measurement of these changes are the basis for CSIA. Caused by differences in the activation energy, light isotopologues often react slightly faster than heavy isotopologues, resulting in enrichment of heavy isotopes at the reactive site in the substrate or of light isotopes in the product. This is termed isotope fractionation. Upon multi-dimensional CSIA (2D-CSIA, 3D-CSIA), the isotope fractionation of two or more different elements within a molecule is determined, allowing highly resolved analyses of degradation processes as masking effects typically occurring in one-dimensional CSIA are cancelled. In the last years, 2D-CSIA making use of the ratio of stable carbon to hydrogen isotopes (13C/12C, 2H/1H), turned out to be an important tool for elucidating the environmental biodegradation pattern of BTEX compounds which are global notorious contaminants. This presentation aims to summarize the current knowledge on 2D-CSIA of BTEX, to point out the prospects and to indicate future perspectives upon monitoring in the field. Degradation experiments for determining carbon and hydrogen isotope fractionation factors were carried out using several pure and mixed cultures performing different BTEX-activating reactions. Various anaerobic key reactions showed pronounced hydrogen isotope fractionation: (i) fumarate addition to the methyl moiety of toluene, xylene isomers and probably ethylbenzene catalyzed by benzylsuccinate synthases, (ii) anaerobic hydroxylation of the ethyl side chain of ethylbenzene catalyzed by ethylbenzene dehydrogenase, and (iii) anaerobic activation of benzene by yet unknown biochemical mechanisms. Due to the high

CAP vessel monitoring. Programme, measurement and neutron calculation

International Nuclear Information System (INIS)

Farrugia, J.M.; Nimal, J.C.; Totth, B.; Lloret, R.; Perdreau, R.

1982-03-01

Starting with the design of the CAP (Prototype Advanced NSSS), a programme for pressure vessel monitoring has been prepared, including dosimetry. The dosimetry programme encompasses activation dosimeters (Cu, Nb, Co) and fission dosimeters ( 237 Np, 238 U) installed either inside the pressure vessel with the monitoring test-samples, or in a counting tube outside the pressure vessel. In the first place, a description of the method for neutronic calculation is given; such calculations use the codes ANISN and MERCURE 4 allowing assessment of the neutron spectrum seen by the detectors and the related reaction coefficient. This is followed by a description of the instrumentation. The initial dosimetry results available after the initial operating cycles concur with calculations [fr

Reaction Decoder Tool (RDT): extracting features from chemical reactions.

Science.gov (United States)

Rahman, Syed Asad; Torrance, Gilliean; Baldacci, Lorenzo; Martínez Cuesta, Sergio; Fenninger, Franz; Gopal, Nimish; Choudhary, Saket; May, John W; Holliday, Gemma L; Steinbeck, Christoph; Thornton, Janet M

2016-07-01

Extracting chemical features like Atom-Atom Mapping (AAM), Bond Changes (BCs) and Reaction Centres from biochemical reactions helps us understand the chemical composition of enzymatic reactions. Reaction Decoder is a robust command line tool, which performs this task with high accuracy. It supports standard chemical input/output exchange formats i.e. RXN/SMILES, computes AAM, highlights BCs and creates images of the mapped reaction. This aids in the analysis of metabolic pathways and the ability to perform comparative studies of chemical reactions based on these features. This software is implemented in Java, supported on Windows, Linux and Mac OSX, and freely available at https://github.com/asad/ReactionDecoder : asad@ebi.ac.uk or s9asad@gmail.com. © The Author 2016. Published by Oxford University Press.

Comparison of DNA testing strategies in monitoring human papillomavirus infection prevalence through simulation

OpenAIRE

Lin, Carol Y.; Li, Ling

2016-01-01

Abstract Background HPV DNA diagnostic tests for epidemiology monitoring (research purpose) or cervical cancer screening (clinical purpose) have often been considered separately. Women with positive Linear Array (LA) polymerase chain reaction (PCR) research test results typically are neither informed nor referred for colposcopy. Recently, a sequential testing by using Hybrid Capture 2 (HC2) HPV clinical test as a triage before genotype by LA has been adopted for monitoring HPV infections. Als...

Modifications of hemoglobin and myoglobin by Maillard reaction products (MRPs).

Science.gov (United States)

Ioannou, Aristos; Varotsis, Constantinos

2017-01-01

High performance liquid chromatography (HPLC) coupled with a Fraction Collector was employed to isolate Maillard reaction products (MRPs) formed in model systems comprising of asparagine and monosaccharides in the 60-180°C range. The primary MRP which is detected at 60°C is important for Acrylamide content and color/aroma development in foods and also in the field of food biotechnology for controlling the extent of the Maillard reaction with temperature. The discrete fractions of the reaction products were reacted with Hemoglobin (Hb) and Myoglobin (Mb) at physiological conditions and the reaction adducts were monitored by UV-vis and Attenuated Total Reflection-Fourier transform infrared (FTIR) spectrophotometry. The UV-vis kinetic profiles revealed the formation of a Soret transition characteristic of a low-spin six-coordinated species and the ATR-FTIR spectrum of the Hb-MRP and Mb-MRP fractions showed modifications in the protein Amide I and II vibrations. The UV-vis and the FTIR spectra of the Hb-MRPs indicate that the six-coordinated species is a hemichrome in which the distal E7 Histidine is coordinated to the heme Fe and blocks irreversibly the ligand binding site. Although the Mb-MRPs complex is a six-coordinated species, the 1608 cm-1 FTIR band characteristic of a hemichrome was not observed.

Synchronous monitoring of muscle dynamics and electromyogram

Science.gov (United States)

Zakir Hossain, M.; Grill, Wolfgang

2011-04-01

A non-intrusive novel detection scheme has been implemented to detect the lateral muscle extension, force of the skeletal muscle and the motor action potential (EMG) synchronously. This allows the comparison of muscle dynamics and EMG signals as a basis for modeling and further studies to determine which architectural parameters are most sensitive to changes in muscle activity. For this purpose the transmission time for ultrasonic chirp signal in the frequency range of 100 kHz to 2.5 MHz passing through the muscle under observation and respective motor action potentials are recorded synchronously to monitor and quantify biomechanical parameters related to muscle performance. Additionally an ultrasonic force sensor has been employed for monitoring. Ultrasonic traducers are placed on the skin to monitor muscle expansion. Surface electrodes are placed suitably to pick up the potential for activation of the monitored muscle. Isometric contraction of the monitored muscle is ensured by restricting the joint motion with the ultrasonic force sensor. Synchronous monitoring was initiated by a software activated audio beep starting at zero time of the subsequent data acquisition interval. Computer controlled electronics are used to generate and detect the ultrasonic signals and monitor the EMG signals. Custom developed software and data analysis is employed to analyze and quantify the monitored data. Reaction time, nerve conduction speed, latent period between the on-set of EMG signals and muscle response, degree of muscle activation and muscle fatigue development, rate of energy expenditure and motor neuron recruitment rate in isometric contraction, and other relevant parameters relating to muscle performance have been quantified with high spatial and temporal resolution.

A study of paint sludge deactivation by pyrolysis reactions

Directory of Open Access Journals (Sweden)

Muniz L.A.R.

2003-01-01

Full Text Available The production of large quantities of paint sludge is a serious environmental problem. This work evaluates the use of pyrolysis reaction as a process for deactivating paint sludge that generates a combustible gas phase, a solvent liquid phase and an inert solid phase. These wastes were classified into three types: water-based solvent (latex resin and solvents based on their resins (alkyd and polyurethane. An electrically heated stainless steel batch reactor with a capacity of 579 mL and a maximum pressure of 30 atm was used. Following the reactor, a flash separator, which was operated at atmospheric pressure, partially condensed and separated liquid and gas products. Pressure and temperature were monitored on-line by a control and data acquisition system, which adjusted the heating power supplied to the pyrolysis reactor. Reactions followed an experimental design with two factors (reaction time and temperature and three levels (10, 50 and 90 minutes; 450, 550 and 650degreesC. The response variables were liquid and solid masses and net heat of combustion. The optimal operational range for the pyrolysis process was obtained for each response variable. A significant reduction in total mass of solid waste was obtained.

Self-compacting paste system using secondary raw materials

International Nuclear Information System (INIS)

Rizwan, S.A.

2008-01-01

A study has been carried out on self-compacting paste (SCP) systems using various cements and secondary raw materials (SRM's) including rice husk ash (RHA) and Silica Fume (SF). These systems were characterized by: SRM particle size, powder water demand (WD) and setting times, flow, strength, microstructure and early volume stability. The result show that WD increased by adding SRM's due to their smaller particle size, higher surface area and internal porosity. Inclusion of SRM's in SCP systems as cement replacements also increase strength of SCP systems due to filler, hydration and pozzolanic actions which translate into pore refinement. It is demonstrated that the resultant properties of self-compacting cementitious. System (SCCS) depend upon the nature of SRM used. (author)

Monitoring Control Applications at CERN

CERN Document Server

Bernard, F; Milcent, H; Petrova, L B; Varela, F

2011-01-01

The Industrial Controls and Engineering (EN-ICE) group [1] of the Engineering Department at CERN has produced, and is responsible for the operation of around 60 applications, which control critical processes in the domains of cryogenics, quench protection systems, power interlocks for the Large Hadron Collider and other subsystems of the accelerator complex. These applications require 24/7 operation and a quick reaction to problems. For this reason the EN-ICE group is presently developing the Monitoring Operation of cOntrols Networks (MOON) tool to detect, anticipate and inform of possible anomalies in the integrity of the applications. The tool builds on top of Simatic WinCC Open Architecture (WinCC OA) [2] SCADA and makes usage of the Joint COntrols Project (JCOP) [3] and the UNified INdustrial COntrol System (UNICOS) [4] Frameworks developed at CERN. The tool provides centralized monitoring and software management of the different elements integrating the control systems like Windows and L...

MONITORING CONTROL APPLICATIONS AT CERN

CERN Document Server

Bernard, F; Milcent, H; Petrova, L B; Varlea, F

2011-01-01

The Industrial Controls and Engineering (EN-ICE) group [1] of the Engineering Department at CERN has produced, and is responsible for the operation of around 60 applications, which control critical processes in the domains of cryogenics, quench protection systems, power interlocks for the Large Hadron Collider and other sub-systems of the accelerator complex. These applications require 24/7 operation and a quick reaction to problems. For this reason the EN-ICE group is presently developing the Monitoring Operation of cOntrols Networks (MOON) tool to detect, anticipate and inform of possible anomalies in the integrity of the applications. The tool builds on top of Simatic WinCC Open Architecture (WinCC OA) [2] SCADA and makes usage of the Joint COntrols Project (JCOP) [3] and the UNified INdustrial COntrol System (UNICOS) [4] Frameworks developed at CERN. The tool provides centralized monitoring and software management of the different elements integrating the control systems like Windows and Linux servers, PL...

Activation cross section of 63Cu(n,α)60Co reaction

International Nuclear Information System (INIS)

Lu Hanlin; Zhao Wenrong; Yu Weixiang; Yuan Xialin

1990-01-01

The mechanical properties of copper during the irradiation with intensive neutron fluence rate are significant for the safe operation of D-T fusion power reactors. The cross sections measured by activation method show a large discrepancy from 36 to 54 mb in 14 MeV region. The cross sections of 69 Cu(n, α) 60 Co reaction were measured by activation method. Two irradiations were carried out at the Cockcroft-wallon and Van de Graaff accelerators of CIAE using T(d, n) 4 He reaction to produce neutrons. The activities of 24 Na and 60 Co γ-rays for monitor and sample foils were determined absolutely by a calibrated Ge(Li) detector system with an accuracy better than 1%. The present results are compared with the others

Things fall apart: Fragmentation reactions in the oxidative aging of organic species

Science.gov (United States)

Kroll, J. H.; Isaacman-VanWertz, G. A.; Wilson, K. R.; Daumit, K. E.; Kessler, S. H.; Lim, C. Y.; Worsnop, D. R.

2016-12-01

The atmospheric oxidation of organic compounds involves a wide array of chemical transformations, including functionalization reactions (addition of polar functional groups to the carbon skeleton), fragmentation reactions (formation of lower carbon-number products via C-C bond scission), and accretion reactions (increases in molecular weight by the combination of two chemical species). Each of these reaction classes can lead to large changes in volatility, and hence can have major implications for atmospheric organic aerosol (OA). For example, the formation of OA is predominantly driven by functionalization and accretion reactions, which generally lead to decreases in volatility. Here we describe a series of laboratory studies of the subsequent organic "aging", the multiday oxidation processes that occur after the initial OA formation and growth. In these studies, the multigenerational oxidation of organic compounds in various phases (the gas phase, the condensed OA phase, and the aqueous phase) is carried out within either an environmental chamber or a flow reactor, and monitored using various high-resolution mass spectrometric techniques. In all cases it is found that fragmentation reactions play a major role in the observed aging chemistry, dominated by the formation of small, volatile oxidation products. These results suggest that multi-day oxidative aging processes do not lead to sustained aerosol growth, but rather may serve as a chemical sink for atmospheric OA.

Potential of atmospheric pressure chemical ionization source in gas chromatography tandem mass spectrometry for the screening of urinary exogenous androgenic anabolic steroids.

Science.gov (United States)

Raro, M; Portolés, T; Pitarch, E; Sancho, J V; Hernández, F; Garrostas, L; Marcos, J; Ventura, R; Segura, J; Pozo, O J

2016-02-04

The atmospheric pressure chemical ionization (APCI) source for gas chromatography-mass spectrometry analysis has been evaluated for the screening of 16 exogenous androgenic anabolic steroids (AAS) in urine. The sample treatment is based on the strategy currently applied in doping control laboratories i.e. enzymatic hydrolysis, liquid-liquid extraction (LLE) and derivatization to form the trimethylsilyl ether-trimethylsilyl enol ether (TMS) derivatives. These TMS derivatives are then analyzed by gas chromatography tandem mass spectrometry using a triple quadrupole instrument (GC-QqQ MS/MS) under selected reaction monitoring (SRM) mode. The APCI promotes soft ionization with very little fragmentation resulting, in most cases, in abundant [M + H](+) or [M + H-2TMSOH](+) ions, which can be chosen as precursor ions for the SRM transitions, improving in this way the selectivity and sensitivity of the method. Specificity of the transitions is also of great relevance, as the presence of endogenous compounds can affect the measurements when using the most abundant ions. The method has been qualitatively validated by spiking six different urine samples at two concentration levels each. Precision was generally satisfactory with RSD values below 25 and 15% at the low and high concentration level, respectively. Most the limits of detection (LOD) were below 0.5 ng mL(-1). Validation results were compared with the commonly used method based on the electron ionization (EI) source. EI analysis was found to be slightly more repeatable whereas lower LODs were found for APCI. In addition, the applicability of the developed method has been tested in samples collected after the administration of 4-chloromethandienone. The highest sensitivity of the APCI method for this compound, allowed to increase the period in which its administration can be detected. Copyright © 2015 Elsevier B.V. All rights reserved.

Analytical improvements of hybrid LC-MS/MS techniques for the efficient evaluation of emerging contaminants in river waters: a case study of the Henares River (Madrid, Spain).

Science.gov (United States)

Pérez-Parada, Andrés; Gómez-Ramos, María del Mar; Martínez Bueno, María Jesús; Uclés, Samanta; Uclés, Ana; Fernández-Alba, Amadeo R

2012-02-01

Instrumental capabilities and software tools of modern hybrid mass spectrometry (MS) instruments such as high-resolution mass spectrometry (HRMS), quadrupole time-of-flight (QTOF), and quadrupole linear ion trap (QLIT) were experimentally investigated for the study of emerging contaminants in Henares River water samples. Automated screening and confirmatory capabilities of QTOF working in full-scan MS and tandem MS (MS/MS) were explored when dealing with real samples. Investigations on the effect of sensitivity and resolution power influence on mass accuracy were studied for the correct assignment of the amoxicillin transformation product 5(R) amoxicillin-diketopiperazine-2',5' as an example of a nontarget compound. On the other hand, a comparison of quantitative and qualitative strategies based on direct injection analysis and off-line solid-phase extraction sample treatment were assayed using two different QLIT instruments for a selected group of emerging contaminants when operating in selected reaction monitoring (SRM) and information-dependent acquisition (IDA) modes. Software-aided screening usually needs a further confirmatory step. Resolving power and MS/MS feature of QTOF showed to confirm/reject most findings in river water, although sensitivity-related limitations are usually found. Superior sensitivity of modern QLIT-MS/MS offered the possibility of direct injection analysis for proper quantitative study of a variety of contaminants, while it simultaneously reduced the matrix effect and increased the reliability of the results. Confirmation of ethylamphetamine, which lacks on a second SRM transition, was accomplished by using the IDA feature. Hybrid MS instruments equipped with high resolution and high sensitivity contributes to enlarge the scope of targeted analytes in river waters. However, in the tested instruments, there is a margin of improvement principally in required sensitivity and data treatment software tools devoted to reliable confirmation

Trace level liquid chromatography tandem mass spectrometry quantification of the mutagenic impurity 2-hydroxypyridine N-oxide as its dansyl derivative.

Science.gov (United States)

Ding, Wei; Huang, Yande; Miller, Scott A; Bolgar, Mark S

2015-03-20

A derivatization LC-MS/MS method was developed and qualified for the trace level quantification of 2-hydroxypyridine N-oxide (HOPO). HOPO is a coupling reagent used in the syntheses of active pharmaceutical ingredients (APIs) to form amide bonds. HOPO was recently confirmed to generate a positive response in a GLP Ames bacterial-reverse-mutation test, classifying it as a mutagenic impurity and as such requiring its control in APIs to the threshold of toxicological concern (TTC). The derivatization reagent 5-dimethylamino-1-naphthalenesulfonyl chloride (dansyl chloride) was used in a basic solution to convert HOPO into the corresponding dansyl-derivative. The derivative was separated from different APIs and reagents by liquid chromatography. The detection of the HOPO dansyl-derivative was achieved by mass spectrometry in selected reaction monitoring (SRM) mode. The LC-MS/MS method had a reporting limit of 0.1ng/mL HOPO, which corresponds to 0.1ppm HOPO relative to an API at 1mg/mL, and a linearity range of 0.1-25ng/mL HOPO analyte. Recoveries of HOPO standards spiked into three different API matrices at 0.2, 1.2, and 20ppm levels were all within 90-100%. An SRM-based confirmatory methodology using the ratios of two fragment ions at three CID energies was developed to verify the identity of HOPO when present at ≥0.6ppm. This identity confirmation can be employed to prevent potential false positive detection of mutagenic impurities at trace level. It can be broadly applicable for the confirmation of analytes when the analytes generate at least two major fragments in tandem mass spectrometry experiments. Copyright © 2015 Elsevier B.V. All rights reserved.

Targeted Proteomics to Assess the Response to Anti-Angiogenic Treatment in Human Glioblastoma (GBM).

Science.gov (United States)

Demeure, Kevin; Fack, Fred; Duriez, Elodie; Tiemann, Katja; Bernard, Amandine; Golebiewska, Anna; Bougnaud, Sébastien; Bjerkvig, Rolf; Domon, Bruno; Niclou, Simone P

2016-02-01

Glioblastoma (GBM) is a highly aggressive primary brain tumor with dismal outcome for affected patients. Because of the significant neo-angiogenesis exhibited by GBMs, anti-angiogenic therapies have been intensively evaluated during the past years. Recent clinical studies were however disappointing, although a subpopulation of patients may benefit from such treatment. We have previously shown that anti-angiogenic targeting in GBM increases hypoxia and leads to a metabolic adaptation toward glycolysis, suggesting that combination treatments also targeting the glycolytic phenotype may be effective in GBM patients. The aim of this study was to identify marker proteins that are altered by treatment and may serve as a short term readout of anti-angiogenic therapy. Ultimately such proteins could be tested as markers of efficacy able to identify patient subpopulations responsive to the treatment. We applied a proteomics approach based on selected reaction monitoring (SRM) to precisely quantify targeted protein candidates, selected from pathways related to metabolism, apoptosis and angiogenesis. The workflow was developed in the context of patient-derived intracranial GBM xenografts developed in rodents and ensured the specific identification of human tumor versus rodent stroma-derived proteins. Quality control experiments were applied to assess sample heterogeneity and reproducibility of SRM assays at different levels. The data demonstrate that tumor specific proteins can be precisely quantified within complex biological samples, reliably identifying small concentration differences induced by the treatment. In line with previous work, we identified decreased levels of TCA cycle enzymes, including isocitrate dehydrogenase, whereas malectin, calnexin, and lactate dehydrogenase A were augmented after treatment. We propose the most responsive proteins of our subset as potential novel biomarkers to assess treatment response after anti-angiogenic therapy that warrant future

Miniature probe for the delivery and monitoring of a photopolymerizable material

Science.gov (United States)

Schmocker, Andreas; Khoushabi, Azadeh; Schizas, Constantin; Bourban, Pierre-Etienne; Pioletti, Dominique P.; Moser, Christophe

2015-12-01

Photopolymerization is a common method to cure materials initially in a liquid state, such as dental implants or bone or tissue fillers. Recent advances in the development of biocompatible gel- and cement-systems open up an avenue for in situ photopolymerization. For minimally invasive surgery, such procedures require miniaturized surgical endoscopic probes to activate and control photopolymerization in situ. We present a miniaturized light probe in which a photoactive material can be (1) mixed, pressurized, and injected, (2) photopolymerized/photoactivated, and (3) monitored during the chemical reaction. The device is used to implant and cure poly(ethylene glycol) dimethacrylate-hydrogel-precursor in situ with ultraviolet A (UVA) light (365 nm) while the polymerization reaction is monitored in real time by collecting the fluorescence and Raman signals generated by the 532-nm excitation light source. Hydrogels could be delivered, photopolymerized, and monitored by the probe up to a curing depth of 4 cm. The size of the photopolymerized samples could be correlated to the fluorescent signal collected by the probe, and the reproducibility of the procedure could be demonstrated. The position of the probe tip inside a bovine caudal intervertebral disc could be estimated in vitro based on the collected fluorescence and Raman signal.

Solar radiation management - on feasibility, side effects, and reaching the 2 degree target

Science.gov (United States)

Korhonen, Hannele; Laakso, Anton; Ekholm, Tommi; Maalick, Zubair; Partanen, Antti-Ilari; Kokkola, Harri; Romakkaniemi, Sami

2015-04-01

Solar radiation management (SRM), i.e. artificially increasing the reflectivity of the Earth, has been suggested as a fast-response, low-cost method to mitigate the impacts of potential rapid future climate change. We have used 1) large eddy simulations as well as an aerosol-climate model and an earth system model to investigate the feasibility and side effects of two types of SRM (marine cloud brightening and stratospheric sulfur injections) and 2) a sequential decision-making approach to determine strategies that combine emission reductions and an uncertain SRM option to limit global mean temperature increase to 2 degree. Regarding stratospheric injections, we find that a large explosive volcanic eruption taking place while SRM is in full force would result in overcooling of the planet, as expected; however, the radiative and climate effects would be clearly smaller than could be expected from the sum of the effects from volcanic eruption alone or SRM alone. In addition, the stratospheric sulphur load would recover from the eruption faster under SRM and natural conditions. If the eruption took place in the high latitudes, the resulting global forcing would be highly dependent on the season of the eruption. Furthermore, regarding marine cloud brightening we find that the spraying of sea water drops leads to cooling due to evaporation and leads to delay in particle dispersion. This delay enhances particle scavenging, and can influence the efficacy of cloud seeding. In terms of combining emission reductions and SRM to reach the 2° C warming target, we find that before the termination risk for SRM can be completely excluded, the acceptable greenhouse gas emission pathways remain only slightly higher than in scenarios without SRM. More generally, the uncertainties in SRM start time, acceptable magnitude and sustainability mean that it can be only a limited substitute to greenhouse gas (GHG) emission reductions. If an additional constraint for CO2 concentration to

Rheological Behavior of Reaction Mixtures during the Graft Copolymerization of Cassava Starch with Acrylic Acid

NARCIS (Netherlands)

Witono, J.R.; Noordergraaf, Inge; Heeres, Hero; Janssen, L.P.B.M.

2017-01-01

Literature data on the rheological behavior of a reaction mixture during the graft copolymerization of acrylic acid onto gelatinized starch are scarce. Yet, such information is important for process design. In this work, continuous torque recording was found to be a suitable method to monitor the

Longitudinal change in quantitative meniscus measurements in knee osteoarthritis - data from the Osteoarthritis Initiative

International Nuclear Information System (INIS)

Bloecker, Katja; Wirth, W.; Eckstein, F.; Guermazi, A.; Hitzl, W.; Hunter, D.J.

2015-01-01

We aimed to apply 3D MRI-based measurement technology to studying 2-year change in quantitative measurements of meniscus size and position. Forty-seven knees from the Osteoarthritis Initiative with medial radiographic joint space narrowing had baseline and 2-year follow-up MRIs. Quantitative measures were obtained from manual segmentation of the menisci and tibia using coronal DESSwe images. The standardized response mean (SRM = mean/SD change) was used as measure of sensitivity to longitudinal change. Medial tibial plateau coverage decreased from 34.8 % to 29.9 % (SRM -0.82; p < 0.001). Change in medial meniscus extrusion in a central image (SRM 0.18) and in the central five slices (SRM 0.22) did not reach significance, but change in extrusion across the entire meniscus (SRM 0.32; p = 0.03) and in the relative area of meniscus extrusion (SRM 0.56; p < 0.001) did. There was a reduction in medial meniscus volume (10 %; p < 0.001), width (7 %; p < 0.001), and height (2 %; p = 0.08); meniscus substance loss was strongest in the posterior (SRM -0.51; p = 0.001) and weakest in the anterior horn (SRM -0.15; p = 0.31). This pilot study reports, for the first time, longitudinal change in quantitative 3D meniscus measurements in knee osteoarthritis. It provides evidence of improved sensitivity to change of 3D measurements compared with single slice analysis. (orig.)

Longitudinal change in quantitative meniscus measurements in knee osteoarthritis - data from the Osteoarthritis Initiative

Energy Technology Data Exchange (ETDEWEB)

Bloecker, Katja [Paracelsus Medical University Salzburg and Nuremberg (Austria); Salzburg, Institute of Anatomy, Salzburg (Austria); BHS Linz, Department of Orthopaedics, Linz (Austria); Wirth, W.; Eckstein, F. [Paracelsus Medical University Salzburg and Nuremberg (Austria); Salzburg, Institute of Anatomy, Salzburg (Austria); Chondrometrics GmbH, Ainring (Germany); Guermazi, A. [Boston University School of Medicine, Boston, MA (United States); Boston Imaging Core Lab (BICL), Boston, MA (United States); Hitzl, W. [Paracelsus Medical University Salzburg and Nuremberg, Research Office, Salzburg (Austria); Hunter, D.J. [University of Sydney, Royal North Shore Hospital and Institute of Bone and Joint Research, Kolling Institute, Sydney (Australia)

2015-10-15

We aimed to apply 3D MRI-based measurement technology to studying 2-year change in quantitative measurements of meniscus size and position. Forty-seven knees from the Osteoarthritis Initiative with medial radiographic joint space narrowing had baseline and 2-year follow-up MRIs. Quantitative measures were obtained from manual segmentation of the menisci and tibia using coronal DESSwe images. The standardized response mean (SRM = mean/SD change) was used as measure of sensitivity to longitudinal change. Medial tibial plateau coverage decreased from 34.8 % to 29.9 % (SRM -0.82; p < 0.001). Change in medial meniscus extrusion in a central image (SRM 0.18) and in the central five slices (SRM 0.22) did not reach significance, but change in extrusion across the entire meniscus (SRM 0.32; p = 0.03) and in the relative area of meniscus extrusion (SRM 0.56; p < 0.001) did. There was a reduction in medial meniscus volume (10 %; p < 0.001), width (7 %; p < 0.001), and height (2 %; p = 0.08); meniscus substance loss was strongest in the posterior (SRM -0.51; p = 0.001) and weakest in the anterior horn (SRM -0.15; p = 0.31). This pilot study reports, for the first time, longitudinal change in quantitative 3D meniscus measurements in knee osteoarthritis. It provides evidence of improved sensitivity to change of 3D measurements compared with single slice analysis. (orig.)

Monitor of dynamic parameters in real time; Monitor de parametros dinamicos en tiempo real

Energy Technology Data Exchange (ETDEWEB)

Rojas S, A.S.; Ruiz E, J.A. [ININ, 52750 La Marquesa, Estado de Mexico (Mexico)

2008-07-01

In the complex physical systems exist parameters that are necessary for monitoring in real time. In the nuclear industry, particularly in a reactor this surveillance is important, where the times of the reactions are almost instantaneous. Although many of these parameters are monitored, given the advance of the computer systems the monitoring could either be enlarged direct or indirect of other parameters. The analysis of the neutron noise in the nuclear reactors, plays an important role, the noise signal it contains information about the operation conditions of a system, when analyzing it with analysis methodologies of analogical signals to provide important information for the early detection of possible flaws and to indicate the permissible operation levels. To show the characteristics of the operation of the system of Monitoring of Dynamic Parameters in Real Time, oscillations of neutron noise of the TRIGA Mark III of the ININ were analyzed, these were caused with the control bar to a power of 10 Watts, the oscillations were carried out to a frequency of 1Hz, signal of low frequency. In this work a virtual instrument that allows by means of the spectral analysis method in frequency point by point is presented, to indicate in real time periodic variations that could be presented in the neutron noise signal, visualizing in advance the dynamic behavior of the system or nuclear plant. Another of the tests of the monitoring system presented is that of the oscillatory event happened in the reactor of Laguna Verde Nucleo electric Central, would be convenient to have an instrument of surveillance for monitoring through the neutron noise signal the behavior of some important parameter to predict and to indicate in an immediate way an abnormal condition in the reactor operation or in the plant system. These parameters can be the power, the recirculation water flow, etc. The monitor is based on a personal computer (PC), a data acquisition card (ADC) and a computer program