ECUT: Energy Conversion and Utilization Technologies program. Chemical Processes project report, FY 1982

NASA Technical Reports Server (NTRS)

Wilcox, R. E. (Compiler)

1983-01-01

Planned research efforts and reorganization of the Project as the Biocatalysis Research Activity are described, including the following topics: electrocatalysts, fluid extraction, ammonia synthesis, biocatalysis, membrane fouling, energy and economic analysis, decarboxylation, microscopic reaction models, plasmid monitoring, and reaction kinetics.

Lab-on-a-chip based total-phosphorus analysis device utilizing a photocatalytic reaction

NASA Astrophysics Data System (ADS)

Jung, Dong Geon; Jung, Daewoong; Kong, Seong Ho

2018-02-01

A lab-on-a-chip (LOC) device for total phosphorus (TP) analysis was fabricated for water quality monitoring. Many commercially available TP analysis systems used to estimate water quality have good sensitivity and accuracy. However, these systems also have many disadvantages such as bulky size, complex pretreatment processes, and high cost, which limit their application. In particular, conventional TP analysis systems require an indispensable pretreatment step, in which the fluidic analyte is heated to 120 °C for 30 min to release the dissolved phosphate, because many phosphates are soluble in water at a standard temperature and pressure. In addition, this pretreatment process requires elevated pressures of up to 1.1 kg cm-2 in order to prevent the evaporation of the heated analyte. Because of these limiting conditions required by the pretreatment processes used in conventional systems, it is difficult to miniaturize TP analysis systems. In this study, we employed a photocatalytic reaction in the pretreatment process. The reaction was carried out by illuminating a photocatalytic titanium dioxide (TiO2) surface formed in a microfluidic channel with ultraviolet (UV) light. This pretreatment process does not require elevated temperatures and pressures. By applying this simplified, photocatalytic-reaction-based pretreatment process to a TP analysis system, greater degrees of freedom are conferred to the design and fabrication of LOC devices for TP monitoring. The fabricated LOC device presented in this paper was characterized by measuring the TP concentration of an unknown sample, and comparing the results with those measured by a conventional TP analysis system. The TP concentrations of the unknown sample measured by the proposed LOC device and the conventional TP analysis system were 0.018 mgP/25 mL and 0.019 mgP/25 mL, respectively. The experimental results revealed that the proposed LOC device had a performance comparable to the conventional bulky TP analysis system. Therefore, our device could be directly employed in water quality monitoring as an alternative to conventional TP analysis systems.

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

PubMed

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.

Enhancing the Pharmacokinetic Profile of Protein-Based Drugs

DTIC Science & Technology

2014-06-12

policy or decision, unless so designated by other documentation. 9. SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O...activated carrier. The reactions were deglycosylated, desalted by ZipTip, and submitted for MALDI-TOF MS analysis. The 0 equivalent control reaction

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

PubMed

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.

Multiple products monitoring as a robust approach for peptide quantification.

PubMed

Baek, Je-Hyun; Kim, Hokeun; Shin, Byunghee; Yu, Myeong-Hee

2009-07-01

Quantification of target peptides and proteins is crucial for biomarker discovery. Approaches such as selected reaction monitoring (SRM) and multiple reaction monitoring (MRM) rely on liquid chromatography and mass spectrometric analysis of defined peptide product ions. These methods are not very widespread because the determination of quantifiable product ion using either SRM or MRM is a very time-consuming process. We developed a novel approach for quantifying target peptides without such an arduous process of ion selection. This method is based on monitoring multiple product ions (multiple products monitoring: MpM) from full-range MS2 spectra of a target precursor. The MpM method uses a scoring system that considers both the absolute intensities of product ions and the similarities between the query MS2 spectrum and the reference MS2 spectrum of the target peptide. Compared with conventional approaches, MpM greatly improves sensitivity and selectivity of peptide quantification using an ion-trap mass spectrometer.

Hydrophilic interaction chromatography-multiple reaction monitoring mass spectrometry method for basic building block analysis of low molecular weight heparins prepared through nitrous acid depolymerization.

PubMed

Sun, Xiaojun; Guo, Zhimou; Yu, Mengqi; Lin, Chao; Sheng, Anran; Wang, Zhiyu; Linhardt, Robert J; Chi, Lianli

2017-01-06

Low molecular weight heparins (LMWHs) are important anticoagulant drugs that are prepared through depolymerization of unfractionated heparin. Based on the types of processing reactions and the structures of the products, LMWHs can be divided into different classifications. Enoxaparin is prepared by benzyl esterification and alkaline depolymerization, while dalteparin and nadroparin are prepared through nitrous acid depolymerization followed by borohydride reduction. Compositional analysis of their basic building blocks is an effective way to provide structural information on heparin and LMWHs. However, most current compositional analysis methods have been limited to heparin and enoxaparin. A sensitive and comprehensive approach is needed for detailed investigation of the structure of LMWHs prepared through nitrous acid depolymerization, especially their characteristic saturated non-reducing end (NRE) and 2,5-anhydro-d-mannitol reducing end (RE). A maltose modified hydrophilic interaction column offers improved separation of complicated mixtures of acidic disaccharides and oligosaccharides. A total of 36 basic building blocks were unambiguously identified by high-resolution tandem mass spectrometry (MS). Multiple reaction monitoring (MRM) MS/MS quantification was developed and validated in the analysis of dalteparin and nadroparin samples. Each group of building blocks revealed different aspects of the properties of LMWHs, such as functional motifs required for anticoagulant activity, the structure of heparin starting materials, cleavage sites in the depolymerization reaction, and undesired structural modifications resulting from side reactions. Copyright © 2016 Elsevier B.V. All rights reserved.

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

PubMed Central

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

Aquatic Analysis.

ERIC Educational Resources Information Center

Mauro, Nicole; Buck-Bernard, Jennifer

1998-01-01

Describes a yearlong project that involves biology students in monitoring water quality. Includes details of the awareness phase, action phase, and presentation phase. Discusses student reaction to the project. (DDR)

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

PubMed

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.

Multiplexed immunosensing and kinetics monitoring in nanofluidic devices with highly enhanced target capture efficiency

PubMed Central

Lin, Yii-Lih; Huang, Yen-Jun; Teerapanich, Pattamon; Leïchlé, Thierry

2016-01-01

Nanofluidic devices promise high reaction efficiency and fast kinetic responses due to the spatial constriction of transported biomolecules with confined molecular diffusion. However, parallel detection of multiple biomolecules, particularly proteins, in highly confined space remains challenging. This study integrates extended nanofluidics with embedded protein microarray to achieve multiplexed real-time biosensing and kinetics monitoring. Implementation of embedded standard-sized antibody microarray is attained by epoxy-silane surface modification and a room-temperature low-aspect-ratio bonding technique. An effective sample transport is achieved by electrokinetic pumping via electroosmotic flow. Through the nanoslit-based spatial confinement, the antigen-antibody binding reaction is enhanced with ∼100% efficiency and may be directly observed with fluorescence microscopy without the requirement of intermediate washing steps. The image-based data provide numerous spatially distributed reaction kinetic curves and are collectively modeled using a simple one-dimensional convection-reaction model. This study represents an integrated nanofluidic solution for real-time multiplexed immunosensing and kinetics monitoring, starting from device fabrication, protein immobilization, device bonding, sample transport, to data analysis at Péclet number less than 1. PMID:27375819

Selected reaction monitoring mass spectrometry: a methodology overview.

PubMed

Ebhardt, H Alexander

2014-01-01

Moving past the discovery phase of proteomics, the term targeted proteomics combines multiple approaches investigating a certain set of proteins in more detail. One such targeted proteomics approach is the combination of liquid chromatography and selected or multiple reaction monitoring mass spectrometry (SRM, MRM). SRM-MS requires prior knowledge of the fragmentation pattern of peptides, as the presence of the analyte in a sample is determined by measuring the m/z values of predefined precursor and fragment ions. Using scheduled SRM-MS, many analytes can robustly be monitored allowing for high-throughput sample analysis of the same set of proteins over many conditions. In this chapter, fundaments of SRM-MS are explained as well as an optimized SRM pipeline from assay generation to data analyzed.

Comparison of Enterococcus quantitative polymerase chain reaction analysis results from midwest U.S. river samples using EPA Method 1611 and Method 1609 PCR reagents

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) has provided recommended beach advisory values in its 2012 recreational water quality criteria (RWQC) for states wishing to use quantitative polymerase chain reaction (qPCR) for the monitoring of Enterococcus fecal indicator bacteria...

Simultaneous 19F-1H medium resolution NMR spectroscopy for online reaction monitoring

NASA Astrophysics Data System (ADS)

Zientek, Nicolai; Laurain, Clément; Meyer, Klas; Kraume, Matthias; Guthausen, Gisela; Maiwald, Michael

2014-12-01

Medium resolution nuclear magnetic resonance (MR-NMR) spectroscopy is currently a fast developing field, which has an enormous potential to become an important analytical tool for reaction monitoring, in hyphenated techniques, and for systematic investigations of complex mixtures. The recent developments of innovative MR-NMR spectrometers are therefore remarkable due to their possible applications in quality control, education, and process monitoring. MR-NMR spectroscopy can beneficially be applied for fast, non-invasive, and volume integrating analyses under rough environmental conditions. Within this study, a simple 1/16″ fluorinated ethylene propylene (FEP) tube with an ID of 0.04″ (1.02 mm) was used as a flow cell in combination with a 5 mm glass Dewar tube inserted into a benchtop MR-NMR spectrometer with a 1H Larmor frequency of 43.32 MHz and 40.68 MHz for 19F. For the first time, quasi-simultaneous proton and fluorine NMR spectra were recorded with a series of alternating 19F and 1H single scan spectra along the reaction time coordinate of a homogeneously catalysed esterification model reaction containing fluorinated compounds. The results were compared to quantitative NMR spectra from a hyphenated 500 MHz online NMR instrument for validation. Automation of handling, pre-processing, and analysis of NMR data becomes increasingly important for process monitoring applications of online NMR spectroscopy and for its technical and practical acceptance. Thus, NMR spectra were automatically baseline corrected and phased using the minimum entropy method. Data analysis schemes were designed such that they are based on simple direct integration or first principle line fitting, with the aim that the analysis directly revealed molar concentrations from the spectra. Finally, the performance of 1/16″ FEP tube set-up with an ID of 1.02 mm was characterised regarding the limit of detection (LOQ (1H) = 0.335 mol L-1 and LOQ (19F) = 0.130 mol L-1 for trifluoroethanol in D2O (single scan)) and maximum quantitative flow rates up to 0.3 mL min-1. Thus, a series of single scan 19F and 1H NMR spectra acquired with this simple set-up already presents a valuable basis for quantitative reaction monitoring.

Product differentiation by analysis of DNA melting curves during the polymerase chain reaction.

PubMed

Ririe, K M; Rasmussen, R P; Wittwer, C T

1997-02-15

A microvolume fluorometer integrated with a thermal cycler was used to acquire DNA melting curves during polymerase chain reaction by fluorescence monitoring of the double-stranded DNA specific dye SYBR Green I. Plotting fluorescence as a function of temperature as the thermal cycler heats through the dissociation temperature of the product gives a DNA melting curve. The shape and position of this DNA melting curve are functions of the GC/AT ratio, length, and sequence and can be used to differentiate amplification products separated by less than 2 degrees C in melting temperature. Desired products can be distinguished from undesirable products, in many cases eliminating the need for gel electrophoresis. Analysis of melting curves can extend the dynamic range of initial template quantification when amplification is monitored with double-stranded DNA specific dyes. Complete amplification and analysis of products can be performed in less than 15 min.

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

PubMed

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.

Improved Long-term Outcomes of Patients With Inflammatory Bowel Disease Receiving Proactive Compared With Reactive Monitoring of Serum Concentrations of Infliximab.

PubMed

Papamichael, Konstantinos; Chachu, Karen A; Vajravelu, Ravy K; Vaughn, Byron P; Ni, Josephine; Osterman, Mark T; Cheifetz, Adam S

2017-10-01

Monitoring serum concentrations of tumor necrosis factor antagonists in patients receiving these drugs as treatment for inflammatory bowel disease (IBD), also called therapeutic drug monitoring, is performed either after patient loss of response (reactive drug monitoring) or in patients in clinical remission in which the drug is titrated to a target concentration (proactive drug monitoring). We compared long-term outcomes of patients with IBD undergoing proactive vs reactive monitoring of serum concentrations of infliximab. We performed a multicenter, retrospective study of 264 consecutive patients with IBD (167 with Crohn's disease) receiving infliximab maintenance therapy. The subjects received proactive (n = 130) or reactive (n = 134) drug monitoring, based on measurements of first infliximab concentration and antibodies to infliximab, from September 2006 to January 2015; they were followed through December 2015 (median time of 2.4 years). We analyzed time to treatment failure, first IBD-related surgery or hospitalization, serious infusion reaction, and detection of antibodies to infliximab. Treatment failure was defined as drug discontinuation for loss of response or serious adverse event, or need for surgery. Multiple Cox regression analysis independently associated proactive drug monitoring, compared with reactive monitoring, with reduced risk for treatment failure (hazard ratio [HR], 0.16; 95% confidence interval [CI], 0.09-0.27; P < .001), IBD-related surgery (HR, 0.30; 95% CI, 0.11-0.80; P = .017), IBD-related hospitalization (HR, 0.16; 95% CI, 0.07-0.33; P < .001), antibodies to infliximab (HR, 0.25; 95% CI, 0.07-0.84; P = .025), and serious infusion reaction (HR, 0.17; 95% CI, 0.04-0.78; P = .023). In a retrospective analysis of patients with IBD receiving proactive vs reactive monitoring of serum concentration of infliximab, proactive monitoring was associated with better clinical outcomes, including greater drug durability, less need for IBD-related surgery or hospitalization, and lower risk of antibodies to infliximab or serious infusion reactions. Copyright © 2017 AGA Institute. Published by Elsevier Inc. All rights reserved.

[Irrational use of drugs as a source of drug - induced diseases].

PubMed

Woroń, Jarosław; Porebski, Grzegorz; Kostka-Trabka, Elzbieta; Goszcz, Aleksandra

2007-01-01

The irrational use of medication, by which we understand the administration of drugs for indications where their effectiveness has not been confirmed, the disregard of restrictions and warnings against their use, and the use of drug combinations which do not increase the therapeutic effect but to the contrary increase the risk of adverse drug reactions, is a serious problem encountered in paediatric pharmacotherapy. Each year the centres for monitoring of adverse drug reactions receive many reports, the analysis of which show that the reasons of occurrence of adverse drug reactions after drug administration, are specifically due to irrational use of medications. In order to prevent in an active way the occurrence, of adverse drug reactions following drug administration it is worthwhile to bring to attention the reasons for their occurrence which not infrequently bring about pathological effects. Our work which is based on reports received by the Regional Centre for Adverse Drug Reactions Monitoring in Krakow concerning the occurrence of adverse drug reactions in an attempt to bring to attention in our view important problems in current pharmacotherapy.

MONITORING MYCOTOXIN PRODUCTION AT THE GENETIC LEVEL ON VARIOUS GROWTH SUBSTRATES USING QUANTITATIVE REVERSE TRANSCRIPTION POLYMERASE CHAIN REACTION?EXPERIMENT DESIGN

EPA Science Inventory

The paper describes a method of analyzing the production of mycotoxins at the genetic level by monitoring the intracellular levels of messenger RNA (mRNA). Initial work will focus on threshing out the mycotoxin gene clusters in Stachybotrys chartarum followed by analysis of toxin...

Benzoin Condensation: Monitoring a Chemical Reaction by High-Pressure Liquid Chromatography

ERIC Educational Resources Information Center

Bhattacharya, Apurba; Purohit, Vikram C.; Bellar, Nicholas R.

2004-01-01

High-pressure liquid chromatography (HPLC) is the preferred method of separating a variety of materials in complex mixtures such as pharmaceuticals, polymers, soils, food products and biological fluids and is also considered to be a powerful analytical tool in both academia and industry. The use of HPLC analysis as a means of monitoring and…

Efficient use of retention time for the analysis of 302 drugs in equine plasma by liquid chromatography-MS/MS with scheduled multiple reaction monitoring and instant library searching for doping control.

PubMed

Liu, Ying; Uboh, Cornelius E; Soma, Lawrence R; Li, Xiaoqing; Guan, Fuyu; You, Youwen; Chen, Jin-Wen

2011-09-01

Multiple drug target analysis (MDTA) used in doping control is more efficient than single drug target analysis (SDTA). The number of drugs with the potential for abuse is so extensive that full coverage is not possible with SDTA. To address this problem, a liquid chromatography tandem mass spectrometric method was developed for simultaneous analysis of 302 drugs using a scheduled multiple reaction monitoring (s-MRM) algorithm. With a known retention time of an analyte, the s-MRM algorithm monitors each MRM transition only around its expected retention time. Analytes were recovered from plasma by liquid-liquid extraction. Information-dependent acquisition (IDA) functionality was used to combine s-MRM with enhanced product ion (EPI) scans within the same chromatographic analysis. An EPI spectrum library was also generated for rapid identification of analytes. Analysis time for the 302 drugs was 7 min. Scheduled MRM improved the quality of the chromatograms, signal response, reproducibility, and enhanced signal-to-noise ratio (S/N), resulting in more data points. Reduction in total cycle time from 2.4 s in conventional MRM (c-MRM) to 1 s in s-MRM allowed completion of the EPI scan at the same time. The speed for screening and identification of multiple drugs in equine plasma for doping control analysis was greatly improved by this method.

The selected reaction monitoring/multiple reaction monitoring-based mass spectrometry approach for the accurate quantitation of proteins: clinical applications in the cardiovascular diseases.

PubMed

Gianazza, Erica; Tremoli, Elena; Banfi, Cristina

2014-12-01

Selected reaction monitoring, also known as multiple reaction monitoring, is a powerful targeted mass spectrometry approach for a confident quantitation of proteins/peptides in complex biological samples. In recent years, its optimization and application have become pivotal and of great interest in clinical research to derive useful outcomes for patient care. Thus, selected reaction monitoring/multiple reaction monitoring is now used as a highly sensitive and selective method for the evaluation of protein abundances and biomarker verification with potential applications in medical screening. This review describes technical aspects for the development of a robust multiplex assay and discussing its recent applications in cardiovascular proteomics: verification of promising disease candidates to select only the highest quality peptides/proteins for a preclinical validation, as well as quantitation of protein isoforms and post-translational modifications.

Monitoring the Rate Solvolytic Decomposition of Benzenediazonium Tetrafluoroborate in Aqueous Media Using a pH Electrode

ERIC Educational Resources Information Center

Wiseman, Floyd L.

2005-01-01

A lab rotary experiment using the pH measurements of an aqueous solution to monitor the course of a solvolytic reaction was conducted. This experiment allowed the students to gain experience in taking precise pH measurement, to use nonlinear analysis techniques for analyzing kinetic data and to use the Arrhenius equation for determination of…

Breath acetone monitoring by portable Si:WO3 gas sensors

PubMed Central

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

Off-line real-time FTIR analysis of a process step in imipenem production

NASA Astrophysics Data System (ADS)

Boaz, Jhansi R.; Thomas, Scott M.; Meyerhoffer, Steven M.; Staskiewicz, Steven J.; Lynch, Joseph E.; Egan, Richard S.; Ellison, Dean K.

1992-08-01

We have developed an FT-IR method, using a Spectra-Tech Monit-IR 400 systems, to monitor off-line the completion of a reaction in real-time. The reaction is moisture-sensitive and analysis by more conventional methods (normal-phase HPLC) is difficult to reproduce. The FT-IR method is based on the shift of a diazo band when a conjugated beta-diketone is transformed into a silyl enol ether during the reaction. The reaction mixture is examined directly by IR and does not require sample workup. Data acquisition time is less than one minute. The method has been validated for specificity, precision and accuracy. The results obtained by the FT-IR method for known mixtures and in-process samples compare favorably with those from a normal-phase HPLC method.

EPA CRL MS014: Analysis of Aldicarb, Bromadiolone, Carbofuran, Oxamyl and Methomyl in Water by Multiple Reaction Monitoring Liquid Chromatography / Tandem Mass Spectrometry (LC/MS/MS)

EPA Pesticide Factsheets

Method MS014 describes procedures for solvent extraction of aldicarb, bromadiolone, carbofuran, oxamyl and methomyl from water samples, followed by analysis using liquid chromatography tandem mass spectrometry (LC-MS-MS).

Analysis and Identification of Acid-Base Indicator Dyes by Thin-Layer Chromatography

ERIC Educational Resources Information Center

Clark, Daniel D.

2007-01-01

Thin-layer chromatography (TLC) is a very simple and effective technique that is used by chemists by different purposes, including the monitoring of the progress of a reaction. TLC can also be easily used for the analysis and identification of various acid-base indicator dyes.

IR spectroscopy analysis of pancreatic lipase-related protein 2 interaction with phospholipids: 3. Monitoring DPPC lipolysis in mixed micelles.

PubMed

Mateos-Diaz, Eduardo; Sutto-Ortiz, Priscila; Sahaka, Moulay; Rodriguez, Jorge A; Carrière, Frédéric

2018-03-01

Usual methods for the continuous assay of lipolytic enzyme activities are mainly based on the titration of free fatty acids, surface pressure monitoring or spectrophotometry using substrates labeled with specific probes. These approaches only give a partial information on the chemistry of the lipolysis reaction and additional end-point analyses are often required to quantify both residual substrate and lipolysis products. We used transmission infrared (IR) spectroscopy to monitor simultaneously the hydrolysis of phospholipids by guinea pig pancreatic lipase-related protein 2 (GPLRP2) and the release of lipolysis products. The substrate (DPPC, 1,2-Dipalmitoyl phosphatidylcholine) was mixed with sodium taurodeoxycholate (NaTDC) to form mixed micelles in D 2 O buffer at pD 6 and 8. After hydrogen/deuterium exchange, DPPC hydrolysis by GPLRP2 (100nM) was monitored at 35°C in a liquid cell by recording IR spectra and time-course variations in the CO stretching region. These changes were correlated to variations in the concentrations of DPPC, lysophospholipids (lysoPC) and palmitic acid (Pam) using calibration curves established with these compounds individually mixed with NaTDC. We were thus able to quantify each compound and its time-course variations during the phospholipolysis reaction and to estimate the enzyme activity. To validate the IR analysis, variations in residual DPPC, lysoPC and Pam were also quantified by thin-layer chromatography coupled to densitometry and similar hydrolysis profiles were obtained using both methods. IR spectroscopy can therefore be used to monitor the enzymatic hydrolysis of phospholipids and obtain simultaneously chemical and physicochemical information on substrate and all reaction products (H-bonding, hydration, acyl chain mobility). Copyright © 2017 Elsevier B.V. All rights reserved.

Online UV-visible spectroscopy and multivariate curve resolution as powerful tool for model-free investigation of laccase-catalysed oxidation.

PubMed

Kandelbauer, A; Kessler, W; Kessler, R W

2008-03-01

The laccase-catalysed transformation of indigo carmine (IC) with and without a redox active mediator was studied using online UV-visible spectroscopy. Deconvolution of the mixture spectra obtained during the reaction was performed on a model-free basis using multivariate curve resolution (MCR). Thereby, the time courses of educts, products, and reaction intermediates involved in the transformation were reconstructed without prior mechanistic assumptions. Furthermore, the spectral signature of a reactive intermediate which could not have been detected by a classical hard-modelling approach was extracted from the chemometric analysis. The findings suggest that the combined use of UV-visible spectroscopy and MCR may lead to unexpectedly deep mechanistic evidence otherwise buried in the experimental data. Thus, although rather an unspecific method, UV-visible spectroscopy can prove useful in the monitoring of chemical reactions when combined with MCR. This offers a wide range of chemists a cheap and readily available, highly sensitive tool for chemical reaction online monitoring.

Reference Cross Sections for Charged-particle Monitor Reactions

NASA Astrophysics Data System (ADS)

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.

Quantification of proteins in urine samples using targeted mass spectrometry methods.

PubMed

Khristenko, Nina; Domon, Bruno

2015-01-01

Numerous clinical proteomics studies are focused on the development of biomarkers to improve either diagnostics for early disease detection or the monitoring of the response to the treatment. Although, a wealth of biomarker candidates are available, their evaluation and validation in a true clinical setup remains challenging. In biomarkers evaluation studies, a panel of proteins of interest are systematically analyzed in a large cohort of samples. However, in spite of the latest progresses in mass spectrometry, the consistent detection of pertinent proteins in high complex biological samples is still a challenging task. Thus, targeted LC-MS/MS methods are better suited for the systematic analysis of biomarkers rather than shotgun approaches. This chapter describes the workflow used to perform targeted quantitative analyses of proteins in urinary samples. The peptides, as surrogates of the protein of interest, are commonly measured using a triple quadrupole mass spectrometers operated in selected reaction monitoring (SRM) mode. More recently, the advances in targeted LC-MS/MS analysis based on parallel reaction monitoring (PRM) performed on a quadrupole-orbitrap instrument have allowed to increase the specificity and selectivity of the measurements.

Holographic interferometry imaging monitoring of photodynamic (PDT) reactions in gelatin biophantom

NASA Astrophysics Data System (ADS)

Davidenko, N.; Mahdi, H.; Zheng, X.; Davidenko, I.; Pavlov, V.; Kuranda, N.; Chuprina, N.; Studzinsky, S.; Pandya, A.; Karia, H.; Tajouri, S.; Dervenis, M.; Gergely, C.; Douplik, A.

2018-01-01

Heat and photochemical reactions with human hemoglobin and photosensitizer were monitored by holography interference method in gelatin phantom. The method has successfully facilitated monitoring the reactions as a highresolution refraction index mapping in real time video regime. Methylene Blue was exploited as a photosensitizer.

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

PubMed

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.

Statistical characterization of multiple-reaction monitoring mass spectrometry (MRM-MS) assays for quantitative proteomics

PubMed Central

2012-01-01

Multiple reaction monitoring mass spectrometry (MRM-MS) with stable isotope dilution (SID) is increasingly becoming a widely accepted assay for the quantification of proteins and peptides. These assays have shown great promise in relatively high throughput verification of candidate biomarkers. While the use of MRM-MS assays is well established in the small molecule realm, their introduction and use in proteomics is relatively recent. As such, statistical and computational methods for the analysis of MRM-MS data from proteins and peptides are still being developed. Based on our extensive experience with analyzing a wide range of SID-MRM-MS data, we set forth a methodology for analysis that encompasses significant aspects ranging from data quality assessment, assay characterization including calibration curves, limits of detection (LOD) and quantification (LOQ), and measurement of intra- and interlaboratory precision. We draw upon publicly available seminal datasets to illustrate our methods and algorithms. PMID:23176545

Statistical characterization of multiple-reaction monitoring mass spectrometry (MRM-MS) assays for quantitative proteomics.

PubMed

Mani, D R; Abbatiello, Susan E; Carr, Steven A

2012-01-01

Multiple reaction monitoring mass spectrometry (MRM-MS) with stable isotope dilution (SID) is increasingly becoming a widely accepted assay for the quantification of proteins and peptides. These assays have shown great promise in relatively high throughput verification of candidate biomarkers. While the use of MRM-MS assays is well established in the small molecule realm, their introduction and use in proteomics is relatively recent. As such, statistical and computational methods for the analysis of MRM-MS data from proteins and peptides are still being developed. Based on our extensive experience with analyzing a wide range of SID-MRM-MS data, we set forth a methodology for analysis that encompasses significant aspects ranging from data quality assessment, assay characterization including calibration curves, limits of detection (LOD) and quantification (LOQ), and measurement of intra- and interlaboratory precision. We draw upon publicly available seminal datasets to illustrate our methods and algorithms.

In Situ Monitoring of the Mechanosynthesis of the Archetypal Metal-Organic Framework HKUST-1: Effect of Liquid Additives on the Milling Reactivity.

PubMed

Stolar, Tomislav; Batzdorf, Lisa; Lukin, Stipe; Žilić, Dijana; Motillo, Cristina; Friščić, Tomislav; Emmerling, Franziska; Halasz, Ivan; Užarević, Krunoslav

2017-06-05

We have applied in situ monitoring of mechanochemical reactions by high-energy synchrotron powder X-ray diffraction to study the role of liquid additives on the mechanochemical synthesis of the archetypal metal-organic framework (MOF) HKUST-1, which was one of the first and is still among the most widely investigated MOF materials to be synthesized by solvent-free procedures. It is shown here how the kinetics and mechanisms of the mechanochemical synthesis of HKUST-1 can be influenced by milling conditions and additives, yielding on occasion two new and previously undetected intermediate phases containing a mononuclear copper core, and that finally rearrange to form the HKUST-1 architecture. On the basis of in situ data, we were able to tune and direct the milling reactions toward the formation of these intermediates, which were isolated and characterized by spectroscopic and structural means and their magnetic properties compared to those of HKUST-1. The results have shown that despite the relatively large breadth of analysis available for such widely investigated materials as HKUST-1, in situ monitoring of milling reactions can help in the detection and isolation of new materials and to establish efficient reaction conditions for the mechanochemical synthesis of porous MOFs.

Post-marketing safety monitoring of shenqifuzheng injection: a solution made of dangshen (Radix Codonopsis) and huangqi (Radix Astragali Mongolici).

PubMed

Ai, Qinghua; Zhang, Wen; Xie, Yanming; Huang, Wenhua; Liang, Hong; Cao, Hui

2014-08-01

To identify the potential risk factors associated with Shenqifuzheng injection (SFI), a solution made of Dangshen (Radix Codonopsis) and Huangqi (Radix Astragali Mongolici), for the timely provision of information to regulatory authorities. A comprehensive analysis of the production process, quality standards, pharmacology, post-marketing clinical studies, and safety evaluation using the primary literature of adverse reactions (ADR), case analyses, and systematic reviews, intensive hospital safety monitoring of post-marketing drugs, and data provided by the hospital information system (HIS). Sub-acute toxicity tests suggesting that a dose of 15 mL/kg (concentrated solution) had specific biological effects, whereas a smaller dose engendered no observable effects. Long-term toxicity testing in domestic rabbits showed that after SFI was administered for 90 days, the animals in each dosing group showed no chronic toxic reactions. Among 20 100 cases observed, the incidence of an ADR was 1.85 per thousand. From March to November 2013, of the leading institutions and 22 sub-centers involved in the post-marketing clinical safety intensive hospital monitoring, 21 units completed 8484 cases of monitoring, and reported 23 cases of adverse reactions. No damage to renal function was found using SFI at a dosage and a treatment course larger and longer than that recommended for the adjuvant treatment of tumors. This could reduce the mortality rate of admitted patients based on the analysis of the data provided by the HIS. A total of 16 clinical case reports of adverse reactions related to SFI in 1999-2012 were obtained through literature retrieval. These reports contained information concerning 17 cases, with adverse reaction symptoms including thrombocytopenia, rash, chills, feeling cold, palpitation, dyspnea, edema of a lower extremity, palpebral edema, and superficial vein inflammation, among others. This study introduces "get full access" to the flow of information on medicines regarding their ADR incidence rate and characteristics and factors. It supports the safety of SFI for clinical, research,and production uses based on objective, reliable, and scientific information to provide safe medication.

MRM for the verification of cancer biomarker proteins: recent applications to human plasma and serum.

PubMed

Chambers, Andrew G; Percy, Andrew J; Simon, Romain; Borchers, Christoph H

2014-04-01

Accurate cancer biomarkers are needed for early detection, disease classification, prediction of therapeutic response and monitoring treatment. While there appears to be no shortage of candidate biomarker proteins, a major bottleneck in the biomarker pipeline continues to be their verification by enzyme linked immunosorbent assays. Multiple reaction monitoring (MRM), also known as selected reaction monitoring, is a targeted mass spectrometry approach to protein quantitation and is emerging to bridge the gap between biomarker discovery and clinical validation. Highly multiplexed MRM assays are readily configured and enable simultaneous verification of large numbers of candidates facilitating the development of biomarker panels which can increase specificity. This review focuses on recent applications of MRM to the analysis of plasma and serum from cancer patients for biomarker verification. The current status of this approach is discussed along with future directions for targeted mass spectrometry in clinical biomarker validation.

Method development aspects for the quantitation of pharmaceutical compounds in human plasma with a matrix-assisted laser desorption/ionization source in the multiple reaction monitoring mode.

PubMed

Kovarik, Peter; Grivet, Chantal; Bourgogne, Emmanuel; Hopfgartner, Gérard

2007-01-01

The present work investigates various method development aspects for the quantitative analysis of pharmaceutical compounds in human plasma using matrix-assisted laser desorption/ionization and multiple reaction monitoring (MALDI-MRM). Talinolol was selected as a model analyte. Liquid-liquid extraction (LLE) and protein precipitation were evaluated regarding sensitivity and throughput for the MALDI-MRM technique and its applicability without and with chromatographic separation. Compared to classical electrospray liquid chromatography/mass spectrometry (LC/ESI-MS) method development, with MALDI-MRM the tuning of the analyte in single MS mode is more challenging due to interfering matrix background ions. An approach is proposed using background subtraction. With LLE and using a 200 microL human plasma aliquot acceptable precision and accuracy could be obtained in the range of 1 to 1000 ng/mL without any LC separation. Approximately 3 s were required for one analysis. A full calibration curve and its quality control samples (20 samples) can be analyzed within 1 min. Combining LC with the MALDI analysis allowed improving the linearity down to 50 pg/mL, while reducing the throughput potential only by two-fold. Matrix effects are still a significant issue with MALDI but can be monitored in a similar way to that used for LC/ESI-MS analysis.

A thermal biosensor based on enzyme reaction.

PubMed

Zheng, Yi-Hua; Hua, Tse-Chao; Xu, Fei

2005-01-01

Application of the thermal biosensor as analytical tool is promising due to advantages as universal, simplicity and quick response. A novel thermal biosensor based on enzyme reaction has been developed. This biosensor is a flow injection analysis system and consists of two channels with enzyme reaction column and reference column. The reference column, which is set for eliminating the unspecific heat, is inactived on special enzyme reaction of the ingredient to be detected. The special enzyme reaction takes places in the enzyme reaction column at a constant temperature realizing by a thermoelectric thermostat. Thermal sensor based on the thermoelectric module containing 127 serial BiTe-thermocouples is used to monitor the temperature difference between two streams from the enzyme reaction column and the reference column. The analytical example for dichlorvos shows that this biosensor can be used as analytical tool in medicine and biology.

Research notes : measuring the strain of the road.

DOT National Transportation Integrated Search

2005-09-01

This study will monitor the pavement structure to investigate if the assumptions used in a mechanistic-empirical design analysis are valid, or if adjustments are needed. The study will be assessing the reaction of the pavement structure to traffic lo...

Short term safety assessment of cilazapril.

PubMed

Coulter, D M

1993-11-24

To undertake an event monitoring study of cilazapril in general practice during the early marketing period, to provide some comparisons with other angiotensin converting enzyme inhibitors and to assess the monitoring method. The monitoring was undertaken in the Intensive Medicines Monitoring Programme. Cilazapril was prescribed for mild to moderate hypertension in 996 patients at a recommended dose of 2.5-5.0 mg daily. The monitoring period was six months and practitioners were asked to report all adverse events. A reaction profile was prepared and compared with profiles for lisinopril, enalapril and captopril. The chi-square test was applied to differences in proportions. There were 84 (8.4%) reports describing 133 adverse events; 124 (93%) were assessed as reactions. Withdrawals totalled 53 (5.3%). The most common reactions were cough (2.9%), nausea and vomiting (1.3%) and lethargy (1.1%). Cilazapril had a higher proportion of neurological reactions (p < 0.001) (mainly headache) but a lower proportion of skin reactions (p = 0.001) than the other ACE inhibitors. It also had relatively less diarrhoea and there were differences in the patterns of psychiatric reactions. Cilazapril has a similar reaction profile to other ACE inhibitors but this paper shows differences, some not previously reported, that may assist selection when prescribing. Although there was a high rate of reporting of known adverse reactions, other events were reported at a very low rate and spontaneous reporting is thus confirmed as an unreliable method of monitoring for unexpected adverse reactions.

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

PubMed

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 ground reactions estimation methods to include pathological gaits and natural variability of gait in real-life physical environment.

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

PubMed Central

Shahabpoor, Erfan; Pavic, Aleksandar

2017-01-01

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 ground reactions estimation methods to include pathological gaits and natural variability of gait in real-life physical environment. PMID:28895909

Determination of reaction rates and activation energy in aerobic composting processes for yard waste.

PubMed

Uma, R N; Manjula, G; Meenambal, T

2007-04-01

The reaction rates and activation energy in aerobic composting processes for yard waste were determined using specifically designed reactors. Different mixture ratios were fixed before the commencement of the process. The C/N ratio was found to be optimum for a mixture ratio of 1:6 containing one part of coir pith to six parts of other waste which included yard waste, yeast sludge, poultry yard waste and decomposing culture (Pleurotosis). The path of stabilization of the wastes was continuously monitored by observing various parameters such as temperature, pH, Electrical Conductivity, C.O.D, VS at regular time intervals. Kinetic analysis was done to determine the reaction rates and activation energy for the optimum mixture ratio under forced aeration condition. The results of the analysis clearly indicated that the temperature dependence of the reaction rates followed the Arrhenius equation. The temperature coefficients were also determined. The degradation of the organic fraction of the yard waste could be predicted using first order reaction model.

State-of-the-art MS technology applications in lung disease.

PubMed

Végvári, Ákos; Döme, Balázs

2011-12-01

Two frontline MS technologies, which have recently gained much attention, are discussed within the scope of this review. Besides a brief summary on the contemporary state of lung cancer and chronic obstructive pulmonary disease, the principles of multiple reaction monitoring and matrix assisted laser desorption ionization (MALDI) MS imaging are presented. A comprehensive overview of quantitative mass spectrometry applications is provided, covering multiple reaction monitoring assay developments for analysis of proteins (biomarkers) and low-molecular-weight compounds (drugs) with a special focus on the disease areas of lung cancer and chronic obstructive pulmonary disease. The MALDI-MS imaging applications are discussed similarly, providing references to studies conducted on lung tissues in order to localize drug compounds and protein biomarkers.

Dynamically monitoring the gene expression of dual fluorophore in the cell cycle with quantitative spectrum analysis

NASA Astrophysics Data System (ADS)

Lee, Ja-Yun; Wu, Tzong-Yuan; Hsu, I.-Jen

2008-04-01

The cloning and transcription techniques on gene cloned fluorescent proteins have been widely used in many applications. They have been used as reporters of some conditions in a series of reactions. However, it is usually difficult to monitor the specific target with the exactly number of proteins during the process in turbid media, especially at micrometer scales. We successfully revealed an alternative way to monitor the cell cycle behavior and quantitatively analyzed the target cells with green and red fluorescent proteins (GFP and RFP) during different phases of the cell cycle by quantitatively analyzing its behavior and also monitoring its spatial distribution.

Effects of alcohol on complex performance.

DOT National Transportation Integrated Search

1969-08-01

Nine subjects were tested on a battery of tasks involving monitoring (simple reaction time, choice reaction time, and meter monitoring), two-dimensional compensatory tracking, and mental arithmetic. Three workloads were presented--monitoring plus tra...

Department of Defense Fiscal Year (FY) 2005 Budget Estimates. Research, Development, Test and Evaluation, Defense-Wide. Volume 1 - Defense Advanced Research Projects Agency

DTIC Science & Technology

2004-02-01

UNCLASSIFIED − Conducted experiments to determine the usability of general-purpose anomaly detection algorithms to monitor a large, complex military...reaction and detection modules to perform tailored analysis sequences to monitor environmental conditions, health hazards and physiological states...scalability of lab proven anomaly detection techniques for intrusion detection in real world high volume environments. Narrative Title FY 2003

Development of high through-put Sr isotope analysis for monitoring reservoir integrity for CO{sub 2} storage.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wall, Andy; Jain, Jinesh; Stewart, Brian

2012-01-01

Recent innovations in multi-collector ICP-mass spectrometry (MC-ICP-MS) have allowed for rapid and precise measurements of isotope ratios in geological samples. Naturally occurring Sr isotopes has the potential for use in Monitoring, Verification, and Accounting (MVA) associated with geologic CO2 storage. Sr isotopes can be useful for: Sensitive tracking of brine migration; Determining seal rock leakage; Studying fluid/rock reactions. We have optimized separation chemistry procedures that will allow operators to prepare samples for Sr isotope analysis off site using rapid, low cost methods.

On-line monitoring of volatile organic compounds at pptv levels by means of proton-transfer-reaction mass spectrometry (PTR-MS) medical applications, food control and environmental research

NASA Astrophysics Data System (ADS)

Lindinger, W.; Hansel, A.; Jordan, A.

1998-02-01

A proton transfer reaction mass spectrometer (PTR-MS) system has been developed which allows for on-line measurements of trace components with concentrations as low as a few pptv. The method is based on reactions of H3O+ ions, which perform non-dissociative proton transfer to most of the common volatile organic compounds (VOCs) but do not react with any of the components present in clean air. Medical applications by means of breath analysis allow for monitoring of metabolic processes in the human body, and examples of food research are discussed on the basis of VOC emissions from fruit, coffee and meat. Environmental applications include investigations of VOC emissions from decaying biomatter which have been found to be an important source for tropospheric acetone, methanol and ethanol. On-line monitoring of the diurnal variations of VOCs in the troposphere yield data demonstrating the present sensitivity of PTR-MS to be in the range of a few pptv. Finally, PTR-MS has proven to be an ideal tool to measure Henry's law constants and their dependencies on temperature as well as on the salt content of water.

Evaluation of Multi-tRNA Synthetase Complex by Multiple Reaction Monitoring Mass Spectrometry Coupled with Size Exclusion Chromatography

PubMed Central

Kim, Jun Seok; Lee, Cheolju

2015-01-01

Eight aminoacyl-tRNA synthetases (M, K, Q, D, R, I, EP and LARS) and three auxiliary proteins (AIMP1, 2 and 3) are known to form a multi-tRNA synthetase complex (MSC) in mammalian cells. We combined size exclusion chromatography (SEC) with reversed-phase liquid chromatography multiple reaction monitoring mass spectrometry (RPLC-MRM-MS) to characterize MSC components and free ARS proteins in human embryonic kidney (HEK 293T) cells. Crude cell extract and affinity-purified proteins were fractionated by SEC in non-denaturing state and ARSs were monitored in each fraction by MRM-MS. The eleven MSC components appeared mostly in earlier SEC fractions demonstrating their participation in complex formation. TARSL2 and AIMP2-DX2, despite their low abundance, were co-purified with KARS and detected in the SEC fractions, where MSC appeared. Moreover, other large complex-forming ARS proteins, such as VARS and FARS, were detected in earlier fractions. The MRM-MS results were further confirmed by western blot analysis. Our study demonstrates usefulness of combined SEC-MRM analysis for the characterization of protein complexes and in understanding the behavior of minor isoforms or variant proteins. PMID:26544075

Application of Colorimetric Solid Phase Extraction (C-SPE) to Monitoring Nickel(II) and Lead(II) in Spacecraft Water Supplies

NASA Technical Reports Server (NTRS)

Diaz, Neil C.; Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.; Rutz, Jeff; Mudgett, Paul; Schultz, John

2004-01-01

Archived water samples collected on the International Space Station (ISS) and returned to Earth for analysis have, in a few instances, contained trace levels of heavy metals. Building on our previous advances using Colorimetric Solid Phase Extraction (C-SPE) as a biocide monitoring technique, we are devising methods for the low level monitoring of nickel(II), lead(II) and other heavy metals. C-SPE is a sorption-spectrophotometric platform based on the extraction of analytes onto a membrane impregnated with a colorimetric reagent that are then quantified on the surface of the membrane using a diffuse reflectance spectrophotometer. Along these lines, we have determined nickel(II) via complexation with dimethylglyoxime (DMG) and begun to examine the analysis of lead(II) by its reaction with 2,5- dimercapto-1,3,4-thiadiazole (DMTD) and 4-(2- pyridylazo)-resorcinol (PAR). These developments are also extending a new variant of C-SPE in which immobilized reagents are being incorporated into this methodology in order to optimize sample reaction conditions and to introduce the colorimetric reagent. This paper describes the status of our development of these two new methods.

Evaluation of Multi-tRNA Synthetase Complex by Multiple Reaction Monitoring Mass Spectrometry Coupled with Size Exclusion Chromatography.

PubMed

Park, Seong-Jun; Ahn, Hee-Sung; Kim, Jun Seok; Lee, Cheolju

2015-01-01

Eight aminoacyl-tRNA synthetases (M, K, Q, D, R, I, EP and LARS) and three auxiliary proteins (AIMP1, 2 and 3) are known to form a multi-tRNA synthetase complex (MSC) in mammalian cells. We combined size exclusion chromatography (SEC) with reversed-phase liquid chromatography multiple reaction monitoring mass spectrometry (RPLC-MRM-MS) to characterize MSC components and free ARS proteins in human embryonic kidney (HEK 293T) cells. Crude cell extract and affinity-purified proteins were fractionated by SEC in non-denaturing state and ARSs were monitored in each fraction by MRM-MS. The eleven MSC components appeared mostly in earlier SEC fractions demonstrating their participation in complex formation. TARSL2 and AIMP2-DX2, despite their low abundance, were co-purified with KARS and detected in the SEC fractions, where MSC appeared. Moreover, other large complex-forming ARS proteins, such as VARS and FARS, were detected in earlier fractions. The MRM-MS results were further confirmed by western blot analysis. Our study demonstrates usefulness of combined SEC-MRM analysis for the characterization of protein complexes and in understanding the behavior of minor isoforms or variant proteins.

AGILE/GRID Science Alert Monitoring System: The Workflow and the Crab Flare Case

NASA Astrophysics Data System (ADS)

Bulgarelli, A.; Trifoglio, M.; Gianotti, F.; Tavani, M.; Conforti, V.; Parmiggiani, N.

2013-10-01

During the first five years of the AGILE mission we have observed many gamma-ray transients of Galactic and extragalactic origin. A fast reaction to unexpected transient events is a crucial part of the AGILE monitoring program, because the follow-up of astrophysical transients is a key point for this space mission. We present the workflow and the software developed by the AGILE Team to perform the automatic analysis for the detection of gamma-ray transients. In addition, an App for iPhone will be released enabling the Team to access the monitoring system through mobile phones. In 2010 September the science alert monitoring system presented in this paper recorded a transient phenomena from the Crab Nebula, generating an automated alert sent via email and SMS two hours after the end of an AGILE satellite orbit, i.e. two hours after the Crab flare itself: for this discovery AGILE won the 2012 Bruno Rossi prize. The design of this alert system is maximized to reach the maximum speed, and in this, as in many other cases, AGILE has demonstrated that the reaction speed of the monitoring system is crucial for the scientific return of the mission.

Advances in targeted proteomics and applications to biomedical research

PubMed Central

Shi, Tujin; Song, Ehwang; Nie, Song; Rodland, Karin D.; Liu, Tao; Qian, Wei-Jun; Smith, Richard D.

2016-01-01

Targeted proteomics technique has emerged as a powerful protein quantification tool in systems biology, biomedical research, and increasing for clinical applications. The most widely used targeted proteomics approach, selected reaction monitoring (SRM), also known as multiple reaction monitoring (MRM), can be used for quantification of cellular signaling networks and preclinical verification of candidate protein biomarkers. As an extension to our previous review on advances in SRM sensitivity herein we review recent advances in the method and technology for further enhancing SRM sensitivity (from 2012 to present), and highlighting its broad biomedical applications in human bodily fluids, tissue and cell lines. Furthermore, we also review two recently introduced targeted proteomics approaches, parallel reaction monitoring (PRM) and data-independent acquisition (DIA) with targeted data extraction on fast scanning high-resolution accurate-mass (HR/AM) instruments. Such HR/AM targeted quantification with monitoring all target product ions addresses SRM limitations effectively in specificity and multiplexing; whereas when compared to SRM, PRM and DIA are still in the infancy with a limited number of applications. Thus, for HR/AM targeted quantification we focus our discussion on method development, data processing and analysis, and its advantages and limitations in targeted proteomics. Finally, general perspectives on the potential of achieving both high sensitivity and high sample throughput for large-scale quantification of hundreds of target proteins are discussed. PMID:27302376

Advances in targeted proteomics and applications to biomedical research

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Tujin; Song, Ehwang; Nie, Song

Targeted proteomics technique has emerged as a powerful protein quantification tool in systems biology, biomedical research, and increasing for clinical applications. The most widely used targeted proteomics approach, selected reaction monitoring (SRM), also known as multiple reaction monitoring (MRM), can be used for quantification of cellular signaling networks and preclinical verification of candidate protein biomarkers. As an extension to our previous review on advances in SRM sensitivity (Shi et al., Proteomics, 12, 1074–1092, 2012) herein we review recent advances in the method and technology for further enhancing SRM sensitivity (from 2012 to present), and highlighting its broad biomedical applications inmore » human bodily fluids, tissue and cell lines. Furthermore, we also review two recently introduced targeted proteomics approaches, parallel reaction monitoring (PRM) and data-independent acquisition (DIA) with targeted data extraction on fast scanning high-resolution accurate-mass (HR/AM) instruments. Such HR/AM targeted quantification with monitoring all target product ions addresses SRM limitations effectively in specificity and multiplexing; whereas when compared to SRM, PRM and DIA are still in the infancy with a limited number of applications. Thus, for HR/AM targeted quantification we focus our discussion on method development, data processing and analysis, and its advantages and limitations in targeted proteomics. Finally, general perspectives on the potential of achieving both high sensitivity and high sample throughput for large-scale quantification of hundreds of target proteins are discussed.« less

Development of solvent-free ambient mass spectrometry for green chemistry applications.

PubMed

Liu, Pengyuan; Forni, Amanda; Chen, Hao

2014-04-15

Green chemistry minimizes chemical process hazards in many ways, including eliminating traditional solvents or using alternative recyclable solvents such as ionic liquids. This concept is now adopted in this study for monitoring solvent-free reactions and analysis of ionic liquids, solids, and catalysts by mass spectrometry (MS), without using any solvent. In our approach, probe electrospray ionization (PESI), an ambient ionization method, was employed for this purpose. Neat viscous room-temperature ionic liquids (RTILs) in trace amounts (e.g., 25 nL) could be directly analyzed without sample carryover effect, thereby enabling high-throughput analysis. With the probe being heated, it can also ionize ionic solid compounds such as organometallic complexes as well as a variety of neat neutral solid chemicals (e.g., amines). More importantly, moisture-sensitive samples (e.g., [bmim][AlCl4]) can be successfully ionized. Furthermore, detection of organometallic catalysts (including air-sensitive [Rh-MeDuPHOS][OTf]) in ionic liquids, a traditionally challenging task due to strong ion suppression effect from ionic liquids, can be enabled using PESI. In addition, PESI can be an ideal approach for monitoring solvent-free reactions. Using PESI-MS, we successfully examined the alkylation of amines by alcohols, the conversion of pyrylium into pyridinium, and the condensation of aldehydes with indoles as well as air- and moisture-sensitive reactions such as the oxidation of ferrocene and the condensation of pyrazoles with borohydride. Interestingly, besides the expected reaction products, the reaction intermediates such as the monopyrazolylborate ion were also observed, providing insightful information for reaction mechanisms. We believe that the presented solvent-free PESI-MS method would impact the green chemistry field.

Organisational Pattern Driven Recovery Mechanisms

NASA Astrophysics Data System (ADS)

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.

Thermoluminescence glow curve analysis and CGCD method for erbium doped CaZrO{sub 3} phosphor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tiwari, Ratnesh, E-mail: 31rati@gmail.com; Chopra, Seema

2016-05-06

The manuscript report the synthesis, thermoluminescence study at fixed concentration of Er{sup 3+} (1 mol%) doped CaZrO{sub 3} phosphor. The phosphors were prepared by modified solid state reaction method. The powder sample was characterized by thermoluminescence (TL) glow curve analysis. In TL glow curve the optimized concentration in 1mol% for UV irradiated sample. The kinetic parameters were calculated by computerized glow curve deconvolution (CGCD) techniaue. Trapping parameters gives the information of dosimetry loss in prepared phosphor and its usability in environmental monitoring and for personal monitoring. CGCD is the advance tool for analysis of complicated TL glow curves.

Photo point monitoring handbook—Part A: Field procedures; Part B: Concepts and analysis.

Treesearch

Frederick C. Hall

2002-01-01

This handbook describes quick, effective methods for documenting change in vegetation and soil through repeat photography. It is published in two parts: field procedures in part A and concepts and office analysis in part B. Topics may be effects of logging, change in wildlife habitat, livestock grazing impacts, or stream channel reaction to land management. Land...

Evaluation of Direct Infusion-Multiple Reaction Monitoring Mass Spectrometry for Quantification of Heat Shock Proteins

PubMed Central

Xiang, Yun; Koomen, John M.

2012-01-01

Protein quantification with liquid chromatography-multiple reaction monitoring mass spectrometry (LC-MRM) has emerged as a powerful platform for assessing panels of biomarkers. In this study, direct infusion, using automated, chip-based nanoelectrospray ionization, coupled with MRM (DI-MRM) is used for protein quantification. Removal of the LC separation step increases the importance of evaluating the ratios between the transitions. Therefore, the effects of solvent composition, analyte concentration, spray voltage, and quadrupole resolution settings on fragmentation patterns have been studied using peptide and protein standards. After DI-MRM quantification was evaluated for standards, quantitative assays for the expression of heat shock proteins (HSPs) were translated from LC-MRM to DI-MRM for implementation in cell line models of multiple myeloma. Requirements for DI-MRM assay development are described. Then, the two methods are compared; criteria for effective DI-MRM analysis are reported based on the analysis of HSP expression in digests of whole cell lysates. The increased throughput of DI-MRM analysis is useful for rapid analysis of large batches of similar samples, such as time course measurements of cellular responses to therapy. PMID:22293045

In situ measurement of magnesium carbonate formation from CO2 using static high-pressure and -temperature 13C NMR.

PubMed

Surface, J Andrew; Skemer, Philip; Hayes, Sophia E; Conradi, Mark S

2013-01-02

We explore a new in situ NMR spectroscopy method that possesses the ability to monitor the chemical evolution of supercritical CO(2) in relevant conditions for geological CO(2) sequestration. As a model, we use the fast reaction of the mineral brucite, Mg(OH)(2), with supercritical CO(2) (88 bar) in aqueous conditions at 80 °C. The in situ conversion of CO(2) into metastable and stable carbonates is observed throughout the reaction. After more than 58 h of reaction, the sample was depressurized and analyzed using in situ Raman spectroscopy, where the laser was focused on the undisturbed products through the glass reaction tube. Postreaction, ex situ analysis was performed on the extracted and dried products using Raman spectroscopy, powder X-ray diffraction, and magic-angle spinning (1)H-decoupled (13)C NMR. These separate methods of analysis confirmed a spatial dependence of products, possibly caused by a gradient of reactant availability, pH, and/or a reaction mechanism that involves first forming hydroxy-hydrated (basic, hydrated) carbonates that convert to the end-product, anhydrous magnesite. This carbonation reaction illustrates the importance of static (unmixed) reaction systems at sequestration-like conditions.

Automated selected reaction monitoring software for accurate label-free protein quantification.

PubMed

Teleman, Johan; Karlsson, Christofer; Waldemarson, Sofia; Hansson, Karin; James, Peter; Malmström, Johan; Levander, Fredrik

2012-07-06

Selected reaction monitoring (SRM) is a mass spectrometry method with documented ability to quantify proteins accurately and reproducibly using labeled reference peptides. However, the use of labeled reference peptides becomes impractical if large numbers of peptides are targeted and when high flexibility is desired when selecting peptides. We have developed a label-free quantitative SRM workflow that relies on a new automated algorithm, Anubis, for accurate peak detection. Anubis efficiently removes interfering signals from contaminating peptides to estimate the true signal of the targeted peptides. We evaluated the algorithm on a published multisite data set and achieved results in line with manual data analysis. In complex peptide mixtures from whole proteome digests of Streptococcus pyogenes we achieved a technical variability across the entire proteome abundance range of 6.5-19.2%, which was considerably below the total variation across biological samples. Our results show that the label-free SRM workflow with automated data analysis is feasible for large-scale biological studies, opening up new possibilities for quantitative proteomics and systems biology.

Monitoring single coffee bean roasting by direct volatile compound analysis with proton transfer reaction time-of-flight mass spectrometry.

PubMed

Yener, Sine; Navarini, Luciano; Lonzarich, Valentina; Cappellin, Luca; Märk, Tilmann D; Bonn, Günther K; Biasioli, Franco

2016-09-01

This study applies proton transfer reaction time-of-flight mass spectrometry for the rapid analysis of volatile compounds released from single coffee beans. The headspace volatile profiles of single coffee beans (Coffeea arabica) from different geographical origins (Brazil, Guatemala and Ethiopia) were analyzed via offline profiling at different stages of roasting. The effect of coffee geographical origin was reflected on volatile compound formation that was supported by one-way ANOVA. Clear origin signatures were observed in the formation of different coffee odorants. Copyright © 2016 John Wiley & Sons, Ltd. Copyright © 2016 John Wiley & Sons, Ltd.

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

PubMed

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.

The Next-Generation PCR-Based Quantification Method for Ambient Waters: Digital PCR.

PubMed

Cao, Yiping; Griffith, John F; Weisberg, Stephen B

2016-01-01

Real-time quantitative PCR (qPCR) is increasingly being used for ambient water monitoring, but development of digital polymerase chain reaction (digital PCR) has the potential to further advance the use of molecular techniques in such applications. Digital PCR refines qPCR by partitioning the sample into thousands to millions of miniature reactions that are examined individually for binary endpoint results, with DNA density calculated from the fraction of positives using Poisson statistics. This direct quantification removes the need for standard curves, eliminating the labor and materials associated with creating and running standards with each batch, and removing biases associated with standard variability and mismatching amplification efficiency between standards and samples. Confining reactions and binary endpoint measurements to small partitions also leads to other performance advantages, including reduced susceptibility to inhibition, increased repeatability and reproducibility, and increased capacity to measure multiple targets in one analysis. As such, digital PCR is well suited for ambient water monitoring applications and is particularly advantageous as molecular methods move toward autonomous field application.

[Study of post marketing safety reevaluation of shenqi fuzheng injection].

PubMed

Ai, Qing-Hua; Li, Yuan-Yuan; Xie, Yan-Ming

2014-09-01

In order to promote the Shenqifuzheng injection (SQFZ) clinical medication safety, this study reevaluate on SQFZ post marketing safety study systematically. Including multi center large sample registration type safety monitoring research, the analysis based on national spontaneous reporting system data, the analysis based on the 20 national hospital information system data and literature research. Above the analysis, it suggests that SQFZ has good security. The more adverse drug reaction (ADR) as allergic reactions, mainly involved in the damage of skin, appendages and its systemic damage, serious person can appear allergic shock. ADR/E is more common in the elderly, may be related to medication (tumor) populations. Early warning analysis based on SRS data and literature research are of the view that "phlebitis" has a strong association with SQFZ used.

Temporal and inter-task consistency of heart rate reactivity during active psychological challenge: a twin study.

PubMed

Turner, J R; Carroll, D; Sims, J; Hewitt, J K; Kelly, K A

1986-01-01

Heart rate was monitored while 22 pairs of young male monozygotic and 29 pairs of young male dizygotic twins were exposed to a video game and a mental arithmetic task. The heart rate reactions of the monozygotic twins showed much greater concordance than those of the dizygotic twins. Analysis of the data for the 102 individuals demonstrated reliable inter-task consistency of heart rate reaction. In addition, comparison of the heart rate reactions of ten pairs of monozygotic and ten pairs of dizygotic twins who had been tested more than a year earlier and their present reactivities revealed impressive temporal consistency.

Patient Participation and the Use of Ehealth Tools for Pharmacoviligance.

PubMed

Berrewaerts, Joëlle; Delbecque, Laure; Orban, Pierre; Desseilles, Martin

2016-01-01

In recent years, pharmacovigilance has undergone some major changes. First, the patient's active role in identifying and describing adverse drug reactions (ADRs) has gained recognition. Second, pharmacovigilance has increasingly incorporated information and communications technology (ICT). Patients can now upload their own reports of ADRs online. Data on intensive medication monitoring are now collected via the Internet and smartphones. Worldwide collection of AEs using smart phones might become the leading technique in Low and Middle Income Countries where broad mobile phone service can be managed cheaper than Internet communication. At the same time, researchers are exploring the potential for data sharing via online forums and Internet search engines. In particular we synthetize the Pros and cons of the various methods for gathering pharmacovigilance data (i.e., Web-based spontaneous reporting of adverse drug reactions; Intensive drug monitoring studies; Analysis of online forum postings; Use of mobile phone systems to monitor drug effects). This article describes these advances and highlights their respective contributions.

Patient Participation and the Use of Ehealth Tools for Pharmacoviligance

PubMed Central

Berrewaerts, Joëlle; Delbecque, Laure; Orban, Pierre; Desseilles, Martin

2016-01-01

In recent years, pharmacovigilance has undergone some major changes. First, the patient’s active role in identifying and describing adverse drug reactions (ADRs) has gained recognition. Second, pharmacovigilance has increasingly incorporated information and communications technology (ICT). Patients can now upload their own reports of ADRs online. Data on intensive medication monitoring are now collected via the Internet and smartphones. Worldwide collection of AEs using smart phones might become the leading technique in Low and Middle Income Countries where broad mobile phone service can be managed cheaper than Internet communication. At the same time, researchers are exploring the potential for data sharing via online forums and Internet search engines. In particular we synthetize the Pros and cons of the various methods for gathering pharmacovigilance data (i.e., Web-based spontaneous reporting of adverse drug reactions; Intensive drug monitoring studies; Analysis of online forum postings; Use of mobile phone systems to monitor drug effects). This article describes these advances and highlights their respective contributions. PMID:27148052

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

PubMed

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.

Single-molecule detection of dihydroazulene photo-thermal reaction using break junction technique

NASA Astrophysics Data System (ADS)

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.

Impact of a Pharmacy-Cardiology Collaborative Practice on Dofetilide Safety Monitoring.

PubMed

Quffa, Lieth H; Panna, Mark; Kaufmann, Michael R; McKillop, Matthew; Dietrich, Nicole Maltese; Franck, Andrew J

2017-01-01

Limited studies have been published examining dofetilide's postmarketing use and its recommended monitoring. To evaluate the impact of a collaborative pharmacy-cardiology antiarrhythmic drug (AAD) monitoring program on dofetilide monitoring. This retrospective cohort study was performed to assess if a novel monitoring program improved compliance with dofetilide-specific monitoring parameters based on the Food and Drug Administration's Risk Evaluation and Mitigation Strategy. A total of 30 patients were included in the analysis. The monitoring parameters evaluated included electrocardiogram, serum potassium, serum magnesium, and kidney function. The primary outcome evaluated was the composite of these dofetilide monitoring parameters obtained in each cohort. In the standard cohort, 245 of 352 (69.6%) monitoring parameters were completed versus 134 of 136 (98.5%) in the intervention group ( P < 0.05). A collaborative pharmacy-cardiology AAD monitoring program was associated with a significant improvement in dofetilide monitoring. This improvement could potentially translate into enhanced patient safety outcomes, such as prevention of adverse drug reactions and decreased hospitalizations.

40 CFR 257.24 - Detection monitoring program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Disposal Units Ground-Water Monitoring and Corrective Action § 257.24 Detection monitoring program. (a... unit; (ii) The mobility, stability, and persistence of waste constituents or their reaction products in... constituents, and reaction products in the ground water; and (iv) The concentration or values and coefficients...

Validation of the concentration profiles obtained from the near infrared/multivariate curve resolution monitoring of reactions of epoxy resins using high performance liquid chromatography as a reference method.

PubMed

Garrido, M; Larrechi, M S; Rius, F X

2007-03-07

This paper reports the validation of the results obtained by combining near infrared spectroscopy and multivariate curve resolution-alternating least squares (MCR-ALS) and using high performance liquid chromatography as a reference method, for the model reaction of phenylglycidylether (PGE) and aniline. The results are obtained as concentration profiles over the reaction time. The trueness of the proposed method has been evaluated in terms of lack of bias. The joint test for the intercept and the slope showed that there were no significant differences between the profiles calculated spectroscopically and the ones obtained experimentally by means of the chromatographic reference method at an overall level of confidence of 5%. The uncertainty of the results was estimated by using information derived from the process of assessment of trueness. Such operational aspects as the cost and availability of instrumentation and the length and cost of the analysis were evaluated. The method proposed is a good way of monitoring the reactions of epoxy resins, and it adequately shows how the species concentration varies over time.

Training students in serologic reaction grading increased perceptions of self-efficacy and ability to recognize serologic reactions but decreased grading accuracy.

PubMed

Perry, Holly; Henry, Stephen

2015-06-01

The ability to recognize and grade serologic reactions in manual techniques remains an important skill both for reference laboratories and in disaster-relocated laboratory services. Developing skills in recognizing and grading serologic reactions is limited to some extent by the range of samples available. Twenty-six students studying transfusion science were presented with blinded grading panels consisting of mixes of natural cells and kodecytes (natural cells modified with synthetic blood group antigens) representing a range of serologic grades. Results from 15-minute exercises over 17 contact weeks were assessed to determine if training with grading panels would have an impact on the ability of students to recognize and correctly grade serologic reactions. Twenty-one clinically active practitioners also took part in a single analysis. Grading exercises found that the use of kodecytes and natural negative cells were able to identify deficiencies in both students' and practitioners' ability to recognize negative and grade serologic reactions. The seventeen 15-minute exercises undertaken with students revealed that although there was some improvement in performance in recognizing positive and negative serologic reactions there was also a degradation in ability to accurately grade. Self-assessment showed a major improvement in students' self-efficacy. The use of serologic grading panels created with kodecytes was suitable as a tool to recognize and monitor serologic grading abilities. Evidence suggests that for both students and practitioners to gain and sustain competency in serologic reaction recognition and grading, they will require ongoing training and monitoring of competence. © 2015 AABB.

Preprocessing and Analysis of LC-MS-Based Proteomic Data

PubMed Central

Tsai, Tsung-Heng; Wang, Minkun; Ressom, Habtom W.

2016-01-01

Liquid chromatography coupled with mass spectrometry (LC-MS) has been widely used for profiling protein expression levels. This chapter is focused on LC-MS data preprocessing, which is a crucial step in the analysis of LC-MS based proteomics. We provide a high-level overview, highlight associated challenges, and present a step-by-step example for analysis of data from LC-MS based untargeted proteomic study. Furthermore, key procedures and relevant issues with the subsequent analysis by multiple reaction monitoring (MRM) are discussed. PMID:26519169

Monitoring drug safety in Astrakhan, Russia.

PubMed

Kirilochev, O O; Dorfman, I P; Umerova, A R

2015-01-01

The problem of drug safety will never disappear as new drugs are delivered in increasing numbers. They have high biological activity and adverse drug reactions (ADR) [1]. Currently, adverse drug reactions are the fourth leading cause of death for patients.There are databases of ADRs (Vigibase, Eudravigilance), but we know that ADR manifestations may vary in different countries and regions, due to the demographic, genetic characteristics of the population and the quality of manufactured drugs [2]. In this regard, the study of the ADR at the regional level is very relevant. We aimed to optimize the work on monitoring drug safety in Astrakhan region through pharmacoepidemiological research and development of computer database for analysis of information coming to the center for drug safety monitoring (CDSM). 1. To study the rates of ADR reporting and the structure in the Astrakhan region at the regional center for drug safety monitoring.2. To analyze the outcomes of registered adverse drug reactions.3. To determine the causality of adverse drug reactions.4. To identify reports on the ineffectiveness of drugs.5. To analyze the rates and structure of ADR reporting for drugs prescribed off-label. We studied spontaneous adverse event reporting. The adverse event reports received by the regional CDSM for the period of 2010 to 2014 was analyzed. The groups of drugs were categorized according by Anatomical Therapeutic Chemical classification system. The data were analyzed using Microsoft Office Excel. The likelihood of whether an ADR was actually due to the drugs was assessed with the Naranjo algorithm. The analysis of the results showed that the establishment of the CDSM in September 2010, contributed to improvement of drug safety monitoring in health facilities of the region. Noteworthy was the increasing the number of adverse event reports in 2011 and 2012, compared with the beginning of the year 2010, when the CDSM was not yet functioning.The decrease of adverse event reporting in 2013 and 2014 was due to the fact that doctors in the region had access to better ADR drug information. Along with the increasing number of adverse event reporting we also noted the increase in the number of health facilities that monitored drug safety. The number of health facilities that reported, doubled from 2010 to 2014. We observed the increase in the number of adverse event reports submitted by pharmaceutical companies. General anti-infective drugs for systemic use (class J) were the most common cause of all registered ADRs (44%). Drugs for treatment of tuberculosis (group J04A) were the cause of adverse drug reactions in 34% of reports. ADRs associated with drugs used for treating diseases of cardiovascular system accounted for 16% of case-reports; drugs belonging to the group of Alimentary tract and metabolism (class A) and to the group of Nervous System (class A) were reported to cause ADRs in 10% of cases each. Type A adverse drug reactions, which are usually a consequence of a drug's primary pharmacological effect, were detected in 45% of cases. These reactions were often registered for drugs affecting cardiovascular system (class C), nervous system (class N), dlood and blood forming organs (class B). Type B ADRs were reported in 54% of cases. These were "idiosyncratic" reactions, which could not be predicted on the basis of the drug's main pharmacological action, were not dose-related and were severe [3]. The most frequent cause of type B adverse drug reactions was the General anti-infective medicines for systemic use (Class J). The fatality rate associated with ADRs was 0.3%. Type A adverse drug reactions resulted in death in 38% of cases. Type B ADR (anaphylactic shock) accounted for 62% of the patient's deaths. The Naranjo scale determined the causality of ADRs. The "definite" ADRs were detected in 14% of reports, "probable" - in 47%, and "possible" - in 39% of cases. The rate of reporting associated with ineffectiveness of drugs amounted to 1%. Most often the lack of therapeutic effect was reported in patients receiving drugs of class C (Cardiovascular system, 31% of all cases of inefficiency of drugs). These drugs were used in accordance with their official instructions for use. The proportion of ADR reports for drugs prescribed off-label was 1.4%. The results substantiate the need to continue drug safety monitoring in the Astrakhan region. We plan to further improve the software for ADR analysis.

Comparison of Enterococcus qPCR analysis results from fresh and marine waters on two real-tme instruments

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) will be recommending a quantitativ e polymerase chain reaction (qPCR) method targeting Enterococcus spp. as an option for monitoring recreational beach water quality. A practical consideration for widespread implementation of this o...

NEW TARGET AND CONTROL ASSAYS FOR QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR) ANALYSIS OF ENTEROCOCCI IN WATER

EPA Science Inventory

Enterococci are frequently monitored in water samples as indicators of fecal pollution. Attention is now shifting from culture based methods for enumerating these organisms to more rapid molecular methods such as QPCR. Accurate quantitative analyses by this method requires highly...

RAPID MEASUREMENT OF BACTERIAL FECAL INDICATORS IN SURFACE WATERS BY QUANTITATIVE POLYMERASE CHAIN REACTION (QPCR) ANALYSIS

EPA Science Inventory

Current methods for determining fecal contamination of recreational waters rely on the culture of bacterial indicators and require at least 24 hours to determine whether the water is unsafe for use. By the time monitoring results are available, exposures have already occurred. N...

Comparison of Enterococcus qPCR analysis results from fresh and marine water samples on two real-time instruments - poster

EPA Science Inventory

The U.S. Environmental Protection Agency (EPA) will be recommending a quantitative polymerase chain reaction (qPCR) method targeting Enterococcus spp. as an option for monitoring recreational beach water quality. A practical consideration for widespread implementation of this or ...

Online low-field NMR spectroscopy for process control of an industrial lithiation reaction-automated data analysis.

PubMed

Kern, Simon; Meyer, Klas; Guhl, Svetlana; Gräßer, Patrick; Paul, Andrea; King, Rudibert; Maiwald, Michael

2018-05-01

Monitoring specific chemical properties is the key to chemical process control. Today, mainly optical online methods are applied, which require time- and cost-intensive calibration effort. NMR spectroscopy, with its advantage being a direct comparison method without need for calibration, has a high potential for enabling closed-loop process control while exhibiting short set-up times. Compact NMR instruments make NMR spectroscopy accessible in industrial and rough environments for process monitoring and advanced process control strategies. We present a fully automated data analysis approach which is completely based on physically motivated spectral models as first principles information (indirect hard modeling-IHM) and applied it to a given pharmaceutical lithiation reaction in the framework of the European Union's Horizon 2020 project CONSENS. Online low-field NMR (LF NMR) data was analyzed by IHM with low calibration effort, compared to a multivariate PLS-R (partial least squares regression) approach, and both validated using online high-field NMR (HF NMR) spectroscopy. Graphical abstract NMR sensor module for monitoring of the aromatic coupling of 1-fluoro-2-nitrobenzene (FNB) with aniline to 2-nitrodiphenylamine (NDPA) using lithium-bis(trimethylsilyl) amide (Li-HMDS) in continuous operation. Online 43.5 MHz low-field NMR (LF) was compared to 500 MHz high-field NMR spectroscopy (HF) as reference method.

Biomedical systems analysis program

NASA Technical Reports Server (NTRS)

1979-01-01

Biomedical monitoring programs which were developed to provide a system analysis context for a unified hypothesis for adaptation to space flight are presented and discussed. A real-time system of data analysis and decision making to assure the greatest possible crew safety and mission success is described. Information about man's abilities, limitations, and characteristic reactions to weightless space flight was analyzed and simulation models were developed. The predictive capabilities of simulation models for fluid-electrolyte regulation, erythropoiesis regulation, and calcium regulation are discussed.

Multi-mycotoxin analysis of animal feed and animal-derived food using LC-MS/MS system with timed and highly selective reaction monitoring.

PubMed

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.

Metabolic networks in motion: 13C-based flux analysis

PubMed Central

Sauer, Uwe

2006-01-01

Many properties of complex networks cannot be understood from monitoring the components—not even when comprehensively monitoring all protein or metabolite concentrations—unless such information is connected and integrated through mathematical models. The reason is that static component concentrations, albeit extremely informative, do not contain functional information per se. The functional behavior of a network emerges only through the nonlinear gene, protein, and metabolite interactions across multiple metabolic and regulatory layers. I argue here that intracellular reaction rates are the functional end points of these interactions in metabolic networks, hence are highly relevant for systems biology. Methods for experimental determination of metabolic fluxes differ fundamentally from component concentration measurements; that is, intracellular reaction rates cannot be detected directly, but must be estimated through computer model-based interpretation of stable isotope patterns in products of metabolism. PMID:17102807

Psychophysiological monitoring of operator's emotional stress in aviation and astronautics.

PubMed

Simonov, P V; Frolov, M V; Ivanov, E A

1980-01-01

The level of emotional stress depending on the power of motivation and the estimation by the subject of the probability (possibility) of goal achievement, largely influences the operator's skill performance (that of a pilot, controller, astronaut). A decrease in the emotional tonus leads to drowsiness, lack of vigilance, missing of significant signals, and to slower reactions. The extremely high stress level disorganizes the activity, complicates it with a trend toward untimely acts and reactions to the insignificant signals (false alarms). The best methods to monitor the degree of the operator's emotional state during his skill performance are the integral estimation of the changes in heart-rate and T-peak amplitude, as well as the analysis of spectral and intonational characteristics of the human voice during radio conversation. These methods were tested on paratroopers, pilots in civil aviation, and airport controllers.

Real-time pH monitoring of industrially relevant enzymatic reactions in a microfluidic side-entry reactor (μSER) shows potential for pH control.

PubMed

Gruber, Pia; Marques, Marco P C; Sulzer, Philipp; Wohlgemuth, Roland; Mayr, Torsten; Baganz, Frank; Szita, Nicolas

2017-06-01

Monitoring and control of pH is essential for the control of reaction conditions and reaction progress for any biocatalytic or biotechnological process. Microfluidic enzymatic reactors are increasingly proposed for process development, however typically lack instrumentation, such as pH monitoring. We present a microfluidic side-entry reactor (μSER) and demonstrate for the first time real-time pH monitoring of the progression of an enzymatic reaction in a microfluidic reactor as a first step towards achieving pH control. Two different types of optical pH sensors were integrated at several positions in the reactor channel which enabled pH monitoring between pH 3.5 and pH 8.5, thus a broader range than typically reported. The sensors withstood the thermal bonding temperatures typical of microfluidic device fabrication. Additionally, fluidic inputs along the reaction channel were implemented to adjust the pH of the reaction. Time-course profiles of pH were recorded for a transketolase and a penicillin G acylase catalyzed reaction. Without pH adjustment, the former showed a pH increase of 1 pH unit and the latter a pH decrease of about 2.5 pH units. With pH adjustment, the pH drop of the penicillin G acylase catalyzed reaction was significantly attenuated, the reaction condition kept at a pH suitable for the operation of the enzyme, and the product yield increased. This contribution represents a further step towards fully instrumented and controlled microfluidic reactors for biocatalytic process development. © 2017 The Authors. Biotechnology Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Comparison of Enterococcus qPCR analysis results from fresh and marine water samples on two real-time instruments -

EPA Science Inventory

EPA is currently considering a quantitative polymerase chain reaction (qPCR) method, targeting Enterococcus spp., for beach monitoring. Improvements in the method’s cost-effectiveness may be realized by the use of newer instrumentation such as the Applied Biosystems StepOneTM a...

Glucose Disappearance in Biological Treatment Systems

PubMed Central

Jeris, John S.; Cardenas, Raul R.

1966-01-01

Laboratory scale anaerobic and aerobic treatment units were conditioned with a daily slug-feed of glucose. After a period of acclimation and stabilization, glucose disappearance was monitored continuously after the slug feed. A continuous sampling apparatus is described. Mathematical analysis of the data indicate zero-order reactions for both biological treatment systems. PMID:16349685

Nanopore Analysis of the 5-Guanidinohydantoin to Iminoallantoin Isomerization in Duplex DNA.

PubMed

Zeng, Tao; Fleming, Aaron M; Ding, Yun; Ren, Hang; White, Henry S; Burrows, Cynthia J

2018-04-06

In DNA, guanine oxidation yields diastereomers of 5-guanidinohydantoin (Gh) as one of the major products. In nucleosides and single-stranded DNA, Gh is in a pH-dependent equilibrium with its constitutional isomer iminoallantoin (Ia). Herein, the isomerization reaction between Gh and Ia was monitored in duplex DNA using a protein nanopore by measuring the ionic current when duplex DNA interacts with the pore under an electrophoretic force. Monitoring current levels in this single-molecule method proved to be superior for analysis of population distributions in an equilibrating mixture of four isomers in duplex DNA as a function of pH. The results identified Gh as a major isomer observed when base paired with A, C, or G at pH 6.4-8.4, and Ia was a minor isomer of the reaction mixture that was only observed when the pH was >7.4 in the duplex DNA context. The present results suggest that Gh will be the dominant isomer in duplex DNA under physiological conditions regardless of the base-pairing partner in the duplex.

Depth profile of production yields of natPb(p, xn) 206,205,204,203,202,201Bi nuclear reactions

NASA Astrophysics Data System (ADS)

Mokhtari Oranj, Leila; Jung, Nam-Suk; Kim, Dong-Hyun; Lee, Arim; Bae, Oryun; Lee, Hee-Seock

2016-11-01

Experimental and simulation studies on the depth profiles of production yields of natPb(p, xn) 206,205,204,203,202,201Bi nuclear reactions were carried out. Irradiation experiments were performed at the high-intensity proton linac facility (KOMAC) in Korea. The targets, irradiated by 100-MeV protons, were arranged in a stack consisting of natural Pb, Al, Au foils and Pb plates. The proton beam intensity was determined by activation analysis method using 27Al(p, 3p1n)24Na, 197Au(p, p1n)196Au, and 197Au(p, p3n)194Au monitor reactions and also by Gafchromic film dosimetry method. The yields of produced radio-nuclei in the natPb activation foils and monitor foils were measured by HPGe spectroscopy system. Monte Carlo simulations were performed by FLUKA, PHITS/DCHAIN-SP, and MCNPX/FISPACT codes and the calculated data were compared with the experimental results. A satisfactory agreement was observed between the present experimental data and the simulations.

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

PubMed Central

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 Instagram contains much drug- and pathology specific data for public health monitoring of DDI and ADR, and that complex network analysis provides an important toolbox to extract health-related associations and their support from large-scale social media data. PMID:26776212

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

PubMed

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 contains much drug- and pathology specific data for public health monitoring of DDI and ADR, and that complex network analysis provides an important toolbox to extract health-related associations and their support from large-scale social media data.

YPED: An Integrated Bioinformatics Suite and Database for Mass Spectrometry-based Proteomics Research

PubMed Central

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.

2015-01-01

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. PMID:25712262

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

PubMed

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.

Orbital maneuvering subsystem functional path analysis for performance monitoring fault detection and annunciation

NASA Technical Reports Server (NTRS)

Keesler, E. L.

1974-01-01

The functional paths of the Orbital Maneuver Subsystem (OMS) is defined. The operational flight instrumentation required for performance monitoring, fault detection, and annunciation is described. The OMS is a pressure fed rocket engine propulsion subsystem. One complete OMS shares each of the two auxiliary propulsion subsystem pods with a reaction control subsystem. Each OMS is composed of a pressurization system, a propellant tanking system, and a gimbaled rocket engine. The design, development, and operation of the system are explained. Diagrams of the system are provided.

Unravelling RNA-substrate interactions in a ribozyme-catalysed reaction using fluorescent turn-on probes.

PubMed

Gaffarogullari, Ece Cazibe; Greulich, Peter; Kobitski, Andrei Yu; Nierth, Alexander; Nienhaus, G Ulrich; Jäschke, Andres

2015-04-07

The Diels-Alder reaction is one of the most important C-C bond-forming reactions in organic chemistry, and much effort has been devoted to controlling its enantio- and diastereoselectivity. The Diels-Alderase ribozyme (DAse) catalyses the reaction between anthracene dienes and maleimide dienophiles with multiple-turnover, stereoselectivity, and up to 1100-fold rate acceleration. Here, a new generation of anthracene-BODIPY-based fluorescent probes was developed to monitor catalysis by the DAse. The brightness of these probes increases up to 93-fold upon reaction with N-pentylmaleimide (NPM), making these useful tools for investigating the stereochemistry of the ribozyme-catalysed reaction. With these probes, we observed that the DAse catalyses the reaction with >91% de and >99% ee. The stereochemistry of the major product was determined unambiguously by rotating-frame nuclear Overhauser NMR spectroscopy (ROESY-NMR) and is in agreement with crystallographic structure information. The pronounced fluorescence change of the probes furthermore allowed a complete kinetic analysis, which revealed an ordered bi uni type reaction mechanism, with the dienophile binding first. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

In-line near-infrared (NIR) and Raman spectroscopy coupled with principal component analysis (PCA) for in situ evaluation of the transesterification reaction.

PubMed

Fontalvo-Gómez, Miriam; Colucci, José A; Velez, Natasha; Romañach, Rodolfo J

2013-10-01

Biodiesel was synthesized from different commercially available oils while in-line Raman and near-infrared (NIR) spectra were obtained simultaneously, and the spectral changes that occurred during the reaction were evaluated with principal component analysis (PCA). Raman and NIR spectra were acquired every 30 s with fiber optic probes inserted into the reaction vessel. The reaction was performed at 60-70 °C using magnetic stirring. The time of reaction was 90 min, and during this time, 180 Raman and NIR spectra were collected. NIR spectra were collected using a transflectance probe and an optical path length of 1 mm at 8 cm(-1) spectral resolution and averaging 32 scans; for Raman spectra a 3 s exposure time and three accumulations were adequate for the analysis. Raman spectroscopy showed the ester conversion as evidenced by the displacement of the C=O band from 1747 to 1744 cm(-1) and the decrease in the intensity of the 1000-1050 cm(-1) band and the 1405 cm(-1) band as methanol was consumed in the reaction. NIR spectra also showed the decrease in methanol concentration with the band in the 4750-5000 cm(-1) region; this signal is present in the spectra of the transesterification reaction but not in the neat oils. The variations in the intensity of the methanol band were a main factor in the in-line monitoring of the transesterification reaction using Raman and NIR spectroscopy. The score plot of the first principal component showed the progress of the reaction. The final product was analyzed using (1)H nuclear magnetic resonance ((1)H NMR) spectroscopy and using mid-infrared spectroscopy, confirming the conversion of the oils to biodiesel.

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

NASA Astrophysics Data System (ADS)

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.

Data Pre-Processing for Label-Free Multiple Reaction Monitoring (MRM) Experiments

PubMed Central

Chung, Lisa M.; Colangelo, Christopher M.; Zhao, Hongyu

2014-01-01

Multiple Reaction Monitoring (MRM) conducted on a triple quadrupole mass spectrometer allows researchers to quantify the expression levels of a set of target proteins. Each protein is often characterized by several unique peptides that can be detected by monitoring predetermined fragment ions, called transitions, for each peptide. Concatenating large numbers of MRM transitions into a single assay enables simultaneous quantification of hundreds of peptides and proteins. In recognition of the important role that MRM can play in hypothesis-driven research and its increasing impact on clinical proteomics, targeted proteomics such as MRM was recently selected as the Nature Method of the Year. However, there are many challenges in MRM applications, especially data pre‑processing where many steps still rely on manual inspection of each observation in practice. In this paper, we discuss an analysis pipeline to automate MRM data pre‑processing. This pipeline includes data quality assessment across replicated samples, outlier detection, identification of inaccurate transitions, and data normalization. We demonstrate the utility of our pipeline through its applications to several real MRM data sets. PMID:24905083

Data Pre-Processing for Label-Free Multiple Reaction Monitoring (MRM) Experiments.

PubMed

Chung, Lisa M; Colangelo, Christopher M; Zhao, Hongyu

2014-06-05

Multiple Reaction Monitoring (MRM) conducted on a triple quadrupole mass spectrometer allows researchers to quantify the expression levels of a set of target proteins. Each protein is often characterized by several unique peptides that can be detected by monitoring predetermined fragment ions, called transitions, for each peptide. Concatenating large numbers of MRM transitions into a single assay enables simultaneous quantification of hundreds of peptides and proteins. In recognition of the important role that MRM can play in hypothesis-driven research and its increasing impact on clinical proteomics, targeted proteomics such as MRM was recently selected as the Nature Method of the Year. However, there are many challenges in MRM applications, especially data pre‑processing where many steps still rely on manual inspection of each observation in practice. In this paper, we discuss an analysis pipeline to automate MRM data pre‑processing. This pipeline includes data quality assessment across replicated samples, outlier detection, identification of inaccurate transitions, and data normalization. We demonstrate the utility of our pipeline through its applications to several real MRM data sets.

Myopathy including polymyositis: a likely class adverse effect of proton pump inhibitors?

PubMed

Clark, David W J; Strandell, Johanna

2006-06-01

Polymyositis occurring in patients treated with omeprazole has been signalled as a possible adverse drug reaction (ADR) by the New Zealand Intensive Medicines Monitoring Programme (IMMP) and the WHO Collaborating Centre for International Drug Monitoring: the Uppsala Monitoring Centre (UMC). Polymyositis and other myopathies have also been reported in post-marketing data and in the medical literature in association with proton pump inhibitor (PPI) use. We wished to follow-up these signals and investigate the evidence of causality for the association of polymyositis and other myopathy with PPI use. Spontaneously reported ADRs from national monitoring centres are sent to the WHO ADR database (VigiBase). VigiBase was searched for case reports of the PPIs, omeprazole, pantoprazole, lansoprazole, esomeprazole and rabeprazole, with terms indicative of myopathy, and further information was elicited from the national centres to help establish causality. Literature sources were reviewed for the occurrence of the above terms in combination with PPIs. In total, there were 292 reports of various myopathies with PPIs, excluding 868 cases of 'myalgia'. In this analysis, 69 patients recovered when the drug was withdrawn and, in 15 patients, the reaction re-occurred when the drug was reinstated. In one-third of the 292 cases, the PPI was the single administered drug, and the PPI was the single suspected drug by the reporter in 57% of reports where concomitant medication was used. In this analysis, three index cases are documented. One involves the same patient taking three different PPIs (lansoprazole, esomeprazole and rabeprazole) at different time periods, with myalgia and muscle weakness occurring with all three drugs. In the two other index cases, myopathies with esomeprazole and omeprazole were reported with positive rechallenge, and causality was assessed as 'possible' and 'certain' by the reporting centres. In 27 cases myositis or polymyositis was reported. Other myopathies were reported, including 35 cases with rhabdomyolysis. In 9 of these cases, the PPI was withdrawn and the reaction abated. The PPI was reinstated in one patient, but the reaction did not re-occur. Time to onset was given in 17 of the rhabdomyolysis cases, rhabdomyolysis occurred with the first week in 9 cases, and in 3 cases the reaction occurred between 14 days to 3 months of treatment. In 12 of these patients, an HMG-CoA reductase inhibitor (statin) was taken concomitantly. Case reports from the WHO ADR database, including index cases involving four out of five PPIs, along with evidence of a possible mechanism, provide compelling evidence that there is a causal association between members of the PPI drug class and myopathy including polymyositis. Evidence was also obtained to support the view that PPI use may be associated with occurrence of other myopathies, including the serious reaction rhabdomyolysis.

Transformation of codeine and codeine-6-glucuronide to opioid analogues by urine adulteration with pyridinium chlorochromate: potential issue for urine drug testing.

PubMed

Luong, Susan; Ung, Alison T; Kalman, John; Fu, Shanlin

2014-07-30

Pyridinium chlorochromate (PCC) is the active ingredient of 'Urine Luck', a commercially available in vitro adulterating agent used to conceal the presence of drugs in a urine specimen. The exposure of codeine and its major glucuronide metabolite codeine-6-glucuronide (C6G) to PCC was investigated to determine whether PCC is an effective masking agent for these opiate compounds. Following the addition of PCC to both spiked and authentic codeine and C6G-positive urine specimens, the samples were monitored using liquid chromatography/mass spectrometry (LC/MS). Stable reaction products were identified and characterized using high-resolution MS analysis and, where possible, nuclear magnetic resonance (NMR) analysis. It was determined that PCC effectively oxidizes codeine and C6G, thus altering the original codeine-to-C6G ratio in the urine specimen. Four reaction products were identified for codeine: codeinone, 14-hydroxycodeinone, 6-O-methylcodeine and 8-hydroxy-7,8-dihydrocodeinone. Similarly, three reaction products were identified for C6G: codeinone, codeine and a lactone of C6G (tentative assignment). Besides addressing the complications added to interpretation, more investigation is warranted to further determine their potential for use as markers for monitoring the presence of codeine and C6G in urine specimens adulterated with PCC. Copyright © 2014 John Wiley & Sons, Ltd.

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

PubMed

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.

Tracking Silent Hypersensitivity Reactions to Asparaginase during Leukemia Therapy Using Single-Chip Indirect Plasmonic and Fluorescence Immunosensing.

PubMed

Charbonneau, David M; Breault-Turcot, Julien; Sinnett, Daniel; Krajinovic, Maja; Leclerc, Jean-Marie; Masson, Jean-François; Pelletier, Joelle N

2017-12-22

Microbial asparaginase is an essential component of chemotherapy for the treatment of childhood acute lymphoblastic leukemia (cALL). Silent hypersensitivity reactions to this microbial enzyme need to be monitored accurately during treatment to avoid adverse effects of the drug and its silent inactivation. Here, we present a dual-response anti-asparaginase sensor that combines indirect SPR and fluorescence on a single chip to perform ELISA-type immunosensing, and correlate measurements with classical ELISA. Analysis of serum samples from children undergoing cALL therapy revealed a clear correlation between single-chip indirect SPR/fluorescence immunosensing and ELISA used in clinical settings (R 2 > 0.9). We also report that the portable SPR/fluorescence system had a better sensitivity than classical ELISA to detect antibodies in clinical samples with low antigenicity. This work demonstrates the reliability of dual sensing for monitoring clinically relevant antibody titers in clinical serum samples.

Monitoring mechanistic details in the synthesis of pyrimidines via real-time, ultrafast multidimensional NMR spectroscopy

PubMed Central

Pardo, Zulay D.; Olsen, Greg; Fernández-Valle, María Encarnación; Frydman, Lucio; Martínez-Álvarez, Roberto; Herrera, Antonio

2016-01-01

Recent years have witnessed unprecedented advances in the development of fast multidimensional NMR acquisition techniques. This progress could open valuable new opportunities for the elucidation of chemical and biochemical processes. This study demonstrates one such capability, with the first real-time 2D dynamic analysis of a complex organic reaction relying on unlabeled substrates. Implementing such measurements required the development of new ultrafast 2D methods, capable of monitoring multiple spectral regions of interest as the reaction progressed. The alternate application of these acquisitions in an interleaved, excitation-optimized fashion, allowed us to extract new structural and dynamic insight concerning the reaction between aliphatic ketones and triflic anhydride in the presence of nitriles to yield alkylpyrimidines. Up to 2500 2D NMR data sets were thus collected over the course of this nearly 100 min long reaction, in an approach resembling that used in functional magnetic resonance imaging. With the aid of these new frequency-selective low-gradient-strength experiments, supplemented by chemical shift calculations of the spectral coordinates observed in the 2D heteronuclear correlations, previously postulated intermediates involved in the alkylpyrimidine formation process could be confirmed, and hitherto undetected ones were revealed. The potential and limitations of the resulting methods are discussed. PMID:22283498

Secondary Organic Aerosol Formation from Glyoxal: photochemical versus dark uptake and reversible versus irreversible SOA formation

NASA Astrophysics Data System (ADS)

Waxman, E.; Slowik, J. G.; Kampf, C. J.; Timkovsky, J.; Noziere, B.; Praplan, A. P.; Pfaffenberger, L.; Holzinger, R.; Hoffmann, T.; Dommen, J.; Prevot, A. S.; Baltensperger, U.; Volkamer, R.

2011-12-01

Glyoxal forms secondary organic aerosol (SOA) by partitioning to the aerosol aqueous phase according to Henry's law. The subsequent processing by heterogeneous and multiphase reactions shifts the partitioning towards aerosols. Currently it is not well understood whether these reactions result in reversible or irreversible SOA formation, and what parameters influence the rate limiting step of multiphase processing. We conducted a series of simulation chamber experiments at PSI in April and May 2011 to investigate processing under dark conditions, UV and/or visible light irradiated conditions, and in the presence and absence of OH radicals. Experiments used ammonium sulfate or ammonium sulfate/fulvic acid mixtures as seed aerosols, and were conducted between 50% and 85% relative humidity at approximately constant RH over the course of any given experiment. Glyoxal was produced photochemically from acetylene, using HONO photolysis as the OH radical source. Gas-phase glyoxal was measured by the CU LED-Cavity Enhanced-DOAS. The Thermal-Desorption Proton-Transfer-Reaction Mass Spectrometer (TD-PTR-MS) and Ion Chromatography Mass Spectrometer (IC-MS) monitored both gas and aerosol-phase organic reaction products. Particle composition was monitored by High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS), and HPLC-ESI MS/MS and LC-MS analysis of filter samples.

Secondary Organic Aerosol Formation from Glyoxal: photochemical versus dark uptake and reversible versus irreversible SOA formation

NASA Astrophysics Data System (ADS)

Waxman, E.; Slowik, J.; Kampf, C.; Timkovsky, J.; Noziere, B.; Praplan, A.; Pffafenberger, L.; Holzinger, R.; Hoffmann, T.; Dommen, J.; Prevot, A.; Baltensperger, U.; Volkamer, R.

2012-04-01

Glyoxal forms secondary organic aerosol (SOA) by partitioning to the aerosol aqueous phase according to Henry's law. The subsequent processing by heterogeneous and multiphase reactions shifts the partitioning towards aerosols. Currently it is not well understood whether these reactions result in reversible or irreversible SOA formation, and what parameters influence the rate limiting step of multiphase processing. We conducted a series of simulation chamber experiments at PSI in April and May 2011 to investigate processing under dark conditions, UV and/or visible light irradiated conditions, and in the presence and absence of OH radicals. Experiments used ammonium sulfate or ammonium sulfate/fulvic acid mixtures as seed aerosols, and were conducted between 50% and 85% relative humidity at approximately constant RH over the course of any given experiment. Glyoxal was produced photochemically from acetylene, using HONO photolysis as the OH radical source. Gas-phase glyoxal was measured by the CU LED-Cavity Enhanced-DOAS. The Thermal-Desorption Proton-Transfer-Reaction Mass Spectrometer (TD-PTR-MS) and Ion Chromatography Mass Spectrometer (IC-MS) monitored both gas and aerosol-phase organic reaction products. Particle composition was monitored by High-Resolution Time-of-Flight Aerosol Mass Spectrometry (HR-ToF-AMS), and HPLC-ESI MS/MS and LC-MS analysis of filter samples.

Kinetic analysis of reactions of Si-based epoxy resins by near-infrared spectroscopy, 13C NMR and soft-hard modelling.

PubMed

Garrido, Mariano; Larrechi, Maria Soledad; Rius, F Xavier; Mercado, Luis Adolfo; Galià, Marina

2007-02-05

Soft- and hard-modelling strategy was applied to near-infrared spectroscopy data obtained from monitoring the reaction between glycidyloxydimethylphenyl silane, a silicon-based epoxy monomer, and aniline. On the basis of the pure soft-modelling approach and previous chemical knowledge, a kinetic model for the reaction was proposed. Then, multivariate curve resolution-alternating least squares optimization was carried out under a hard constraint, that compels the concentration profiles to fulfil the proposed kinetic model at each iteration of the optimization process. In this way, the concentration profiles of each species and the corresponding kinetic rate constants of the reaction, unpublished until now, were obtained. The results obtained were contrasted with 13C NMR. The joint interval test of slope and intercept for detecting bias was not significant (alpha=5%).

Glass Reinforcement of Various Epoxy Resins-Polyurea Systems

NASA Astrophysics Data System (ADS)

Joshi, Medha; Jauhari, Smita

2012-07-01

Polyureas (PUs) were prepared by the polycondensation reaction of disperse dyes containing -NH2 group and toluene 2, 4-diisocyanate. The disperse dyes have been prepared by coupling of various 2-diazobenzothiazoles with 1,3-benzenediamine. All the PUs were characterized by elemental analysis, spectral studies, number average molecular weight ( {overline{{Mn}} } ), and thermogravimetry. Further reaction of PUs was carried out with an epoxy resin (i.e., DGEBA). The curing study of prepared resins was monitored by differential scanning calorimeter (DSC). Based on DSC, thermograms glass fiber-reinforced composites have been laminated and characterized by chemical, mechanical, and electrical properties. The unreinforced cured resins were subjected to thermogravimetric analysis (TGA). The laminated composites showed excellent resistance properties against chemicals and good mechanical and electrical properties.

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

ERIC Educational Resources Information Center

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.…

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

PubMed

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.

Liquid Microjunction Surface Sampling Probe Electrospray Mass Spectrometry for Detection of Drugs and Metabolites in Thin Tissue Sections

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Berkel, Gary J; Kertesz, Vilmos; Koeplinger, Kenneth A.

2008-01-01

A self-aspirating, liquid micro-junction surface sampling probe/electrospray emitter mass spectrometry system was demonstrated for use in the direct analysis of spotted and dosed drugs and their metabolites in thin tissue sections. Proof-of-principle sampling and analysis directly from tissue without the need for sample preparation was demonstrated first by raster scanning a region on a section of rat liver onto which reserpine was spotted. The mass spectral signal from selected reaction monitoring was used to develop a chemical image of the spotted drug on the tissue. The probe was also used to selectively spot sample areas of sagittal whole mouse bodymore » tissue sections that had been dosed orally (90 mg/kg) with R,S-sulforaphane 3 hrs prior to sacrifice. Sulforaphane and its glutathione and N-acetyl cysteine conjugates were monitored with selected reaction monitoring and detected in the stomach and various other tissues from the dosed mouse. No signal for these species was observed in the tissue from a control mouse. The same dosed tissue section was used to illustrate the possibility of obtaining a line scan across the whole body section. In total these results illustrate the potential for rapid screening of the distribution of drugs and metabolites in tissue sections with the micro-liquid junction surface sampling probe/electrospray mass spectrometry approach.« less

Conceptual DFT analysis of the fragility spectra of atoms along the minimum energy reaction coordinate.

PubMed

Ordon, Piotr; Komorowski, Ludwik; Jedrzejewski, Mateusz

2017-10-07

Theoretical justification has been provided to the method for monitoring the sequence of chemical bonds' rearrangement along a reaction path, by tracing the evolution of the diagonal elements of the Hessian matrix. Relations between the divergences of Hellman-Feynman forces and the energy and electron density derivatives have been demonstrated. By the proof presented on the grounds of the conceptual density functional theory formalism, the spectral amplitude observed on the atomic fragility spectra [L. Komorowski et al., Phys. Chem. Chem. Phys. 18, 32658 (2016)] reflects selectively the electron density modifications in bonds of an atom. In fact the spectral peaks for an atom reveal changes of the electron density occurring with bonds creation, breaking, or varying with the reaction progress.

Conceptual DFT analysis of the fragility spectra of atoms along the minimum energy reaction coordinate

NASA Astrophysics Data System (ADS)

Ordon, Piotr; Komorowski, Ludwik; Jedrzejewski, Mateusz

2017-10-01

Theoretical justification has been provided to the method for monitoring the sequence of chemical bonds' rearrangement along a reaction path, by tracing the evolution of the diagonal elements of the Hessian matrix. Relations between the divergences of Hellman-Feynman forces and the energy and electron density derivatives have been demonstrated. By the proof presented on the grounds of the conceptual density functional theory formalism, the spectral amplitude observed on the atomic fragility spectra [L. Komorowski et al., Phys. Chem. Chem. Phys. 18, 32658 (2016)] reflects selectively the electron density modifications in bonds of an atom. In fact the spectral peaks for an atom reveal changes of the electron density occurring with bonds creation, breaking, or varying with the reaction progress.

A self optimizing synthetic organic reactor system using real-time in-line NMR spectroscopy.

PubMed

Sans, Victor; Porwol, Luzian; Dragone, Vincenza; Cronin, Leroy

2015-02-01

A configurable platform for synthetic chemistry incorporating an in-line benchtop NMR that is capable of monitoring and controlling organic reactions in real-time is presented. The platform is controlled via a modular LabView software control system for the hardware, NMR, data analysis and feedback optimization. Using this platform we report the real-time advanced structural characterization of reaction mixtures, including 19 F, 13 C, DEPT, 2D NMR spectroscopy (COSY, HSQC and 19 F-COSY) for the first time. Finally, the potential of this technique is demonstrated through the optimization of a catalytic organic reaction in real-time, showing its applicability to self-optimizing systems using criteria such as stereoselectivity, multi-nuclear measurements or 2D correlations.

From the Children’s Oncology Group: Evidence-based recommendations for PEG-asparaginase nurse monitoring, hypersensitivity reaction management, and patient/family education

PubMed Central

Woods, Deborah; Winchester, Kari; Towerman, Alison; Gettinger, Katie; Carey, Christina; Timmermann, Karen; Langley, Rachel; Browne, Emily

2017-01-01

PEG-aspariginase is a backbone chemotherapy agent in pediatric acute lymphoblastic leukemia and in some non-Hodgkin lymphoma therapies. Nurses lack standardized guidelines for monitoring patients receiving PEG-asparaginase and for educating patients/families about hypersensitivity reaction risks. An electronic search of six databases using publication years 2000–2015 and multiple professional organizations and clinical resources was conducted. Evidence sources were reviewed for topic applicability. Each of the final 23 sources was appraised by two team members. The GRADE system was used to assign a quality and strength rating for each recommendation. Multiple recommendations were developed: four relating to nurse monitoring of patients during and after drug administration, eight guiding hypersensitivity reaction management, and four concerning patient/family educational content. These strong recommendations were based on moderate, low, or very-low quality evidence. Several recommendations relied upon generalized drug hypersensitivity guidelines. Additional research is needed to safely guide PEG-asparaginase monitoring, hypersensitivity reaction management and patient/family education. Nurses administering PEG-asparaginase play a critical role in the early identification and management of hypersensitivity reactions. PMID:28602129

Webcam camera as a detector for a simple lab-on-chip time based approach.

PubMed

Wongwilai, Wasin; Lapanantnoppakhun, Somchai; Grudpan, Supara; Grudpan, Kate

2010-05-15

A modification of a webcam camera for use as a small and low cost detector was demonstrated with a simple lab-on-chip reactor. Real time continuous monitoring of the reaction zone could be done. Acid-base neutralization with phenolphthalein indicator was used as a model reaction. The fading of pink color of the indicator when the acidic solution diffused into the basic solution zone was recorded as the change of red, blue and green colors (%RBG.) The change was related to acid concentration. A low cost portable semi-automation analysis system was achieved.

Quantification of Daily Physical Activity

NASA Technical Reports Server (NTRS)

Whalen, Robert; Breit, Greg; Quintana, Jason

1994-01-01

The influence of physical activity on the maintenance and adaptation of musculoskeletal tissue is difficult to assess. Cumulative musculoskeletal loading is hard to quantify and the attributes of the daily tissue loading history affecting bone metabolism have not been completely identified. By monitoring the vertical component of the daily ground reaction force (GRFz), we have an indirect measure of cumulative daily lower limb musculoskeletal loading to correlate with bone density and structure. The objective of this research is to develop instrumentation and methods of analysis to quantify activity level in terms of the daily history of ground reaction forces.

A novel thermal biosensor based on enzyme reaction for pesticides measurement.

PubMed

Zheng, Yi-Hu; Hua, Tse-Chao; Xu, Fei

2005-01-01

A novel thermal biosensor based on enzyme reaction for pesticides detection has been developed. This biosensor is a flow injection analysis system and consists of two channels with enzyme reaction column and identical reference column, which is set for eliminating the unspecific heat. The enzyme reaction takes place in the enzyme reaction column at a constant temperature (40 degrees C) realized by a thermoelectric thermostat. Thermosensor based on the thermoelectric module containing 127 serial BiTe-thermocouples is used to monitor the temperature difference between two effluents from enzyme reaction column and reference column. The ability of this biosensor to detect pesticides is demonstrated by the decreased degree of the hydrolytic heat in two types of thermosensor mode. The hydrolytic reaction is inhibited by 36% at 1 mg/L DDVP and 50% at 10 mg/L DDVP when cell-typed thermosensor is used. The percent inhibition is 30% at 1 mg/L DDVP and 42% at 10 mg/L DDVP in tube-typed thermosensor mode. The detection for real sample shows that this biosensor can be used for detection of organophosphate pesticides residue.

Value of molecular monitoring during the treatment of chronic myeloid leukemia: a Cancer and Leukemia Group B study.

PubMed

Stock, W; Westbrook, C A; Peterson, B; Arthur, D C; Szatrowski, T P; Silver, R T; Sher, D A; Wu, D; Le Beau, M M; Schiffer, C A; Bloomfield, C D

1997-01-01

Disappearance of the Philadelphia chromosome during treatment for chronic myeloid leukemia (CML) has become an important therapeutic end point. To determine the additional value of molecular monitoring during treatment for CML, we performed a prospective, sequential analysis using quantitative Southern blot monitoring of BCR gene rearrangements of blood and marrow samples from Cancer and Leukemia Group B (CALGB) study 8761. Sixty-four previously untreated adults with chronic-phase CML who were enrolled onto CALGB 8761, a molecular-monitoring companion study to a treatment study for adults with chronic-phase CML (CALGB 9013). Treatment consisted of repetitive cycles of interferon alfa and low-dose subcutaneous cytarabine. Blood and marrow Southern blot quantitation of BCR gene rearrangements was compared with marrow cytogenetic analysis before the initiation of treatment and of specified points during therapy. Reverse-transcriptase polymerase chain reaction (RT-PCR) analysis was performed to detect residual disease in patients who achieved a complete response by Southern blot or cytogenetic analysis. Quantitative molecular monitoring by Southern blot analysis of blood samples was found to be equivalent to marrow monitoring at all time points. Twelve of 62 (19%) follow-up samples studied by Southern blot analysis had a complete loss of BCR gene rearrangement in matched marrow and blood specimens. Southern blot monitoring of blood samples was also found to be highly correlated to marrow cytogenetic evaluation at all points, although there were four discordant cases in which Southern blot analysis of blood showed no BCR gene rearrangement, yet demonstrated from 12% to 20% Philadelphia chromosome-positive metaphase cells in the marrow. RT-PCR analysis detected residual disease in five of six patients in whom no malignant cells were detected using Southern blot or cytogenetic analyses. Quantitative Southern blot analysis of blood samples may be substituted for bone marrow to monitor the response to therapy in CML and results in the need for fewer bone marrow examinations. To avoid overestimating the degree of response, marrow cytogenetic analysis should be performed when patients achieve a complete response by Southern blot monitoring. This approach provides a rational, cost-effective strategy to monitor the effect of treatment of individual patients, as well as to analyze large clinical trials in CML.

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

PubMed Central

Choi1, Yong Seok; Lee, Kelvin H.

2016-01-01

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 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 R2 = 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. PMID:26404792

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.

PubMed

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.

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

PubMed

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.

Intact protein analysis of ubiquitin in cerebrospinal fluid by multiple reaction monitoring reveals differences in Alzheimer's disease and frontotemporal lobar degeneration.

PubMed

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.

Monitoring variations of dimethyl sulfide and dimethylsulfoniopropionate in seawater and the atmosphere based on sequential vapor generation and ion molecule reaction mass spectrometry.

PubMed

Iyadomi, Satoshi; Ezoe, Kentaro; Ohira, Shin-Ichi; Toda, Kei

2016-04-01

To monitor the fluctuations of dimethyl sulfur compounds at the seawater/atmosphere interface, an automated system was developed based on sequential injection analysis coupled with vapor generation-ion molecule reaction mass spectrometry (SIA-VG-IMRMS). Using this analytical system, dissolved dimethyl sulfide (DMS(aq)) and dimethylsulfoniopropionate (DMSP), a precursor to DMS in seawater, were monitored together sequentially with atmospheric dimethyl sulfide (DMS(g)). A shift from the equilibrium point between DMS(aq) and DMS(g) results in the emission of DMS to the atmosphere. Atmospheric DMS emitted from seawater plays an important role as a source of cloud condensation nuclei, which influences the oceanic climate. Water samples were taken periodically and dissolved DMS(aq) was vaporized for analysis by IMRMS. After that, DMSP was hydrolyzed to DMS and acrylic acid, and analyzed in the same manner as DMS(aq). The vaporization behavior and hydrolysis of DMSP to DMS were investigated to optimize these conditions. Frequent (every 30 min) determination of the three components, DMS(aq)/DMSP (nanomolar) and DMS(g) (ppbv), was carried out by SIA-VG-IMRMS. Field analysis of the dimethyl sulfur compounds was undertaken at a coastal station, which succeeded in showing detailed variations of the compounds in a natural setting. Observed concentrations of the dimethyl sulfur compounds both in the atmosphere and seawater largely changed with time and similar variations were repeatedly observed over several days, suggesting diurnal variations in the DMS flux at the seawater/atmosphere interface.

Quantitative Raman spectroscopy as a tool to study the kinetics and formation mechanism of carbonates.

PubMed

Bonales, L J; Muñoz-Iglesias, V; Santamaría-Pérez, D; Caceres, M; Fernandez-Remolar, D; Prieto-Ballesteros, O

2013-12-01

We have carried out a systematic study of abiotic precipitation at different temperatures of several Mg and Ca carbonates (calcite, nesquehonite, hydrocalcite) present in carbonaceous chondrites. This study highlights the capability of Raman spectroscopy as a primary tool for performing full mineralogical analysis. The precipitation reaction and the structure of the resulting carbonates were monitored and identified with Raman spectroscopy. Raman spectroscopy enabled us to confirm that the precipitation reaction is very fast (minutes) when Ca(II) is present in the solution, whereas for Mg(II) such reactions developed at rather slow rates (weeks). We also observed that both the composition and the reaction mechanisms depended on temperature, which might help to clarify several issues in the fields of planetology and geology, because of the environmental implications of these carbonates on both terrestrial and extraterrestrial objects. Copyright © 2013 Elsevier B.V. All rights reserved.

Mechanistic insights into lithium ion battery electrolyte degradation - a quantitative NMR study.

PubMed

Wiemers-Meyer, S; Winter, M; Nowak, S

2016-09-29

The changes in electrolyte composition on the molecular level and the reaction mechanisms of electrolyte degradation upon thermal aging are monitored by quantitative NMR spectroscopy, revealing similar rates of degradation for pristine and already aged electrolytes. The data analysis is not in favor of an autocatalytic reaction mechanism based on OPF 3 but rather indicates that the degradation of LiPF 6 in carbonate based solvents proceeds via a complex sequence of "linear" reactions rather than a cyclic reaction pattern which is determined by the amount of water present in the samples. All investigated electrolytes are reasonably stable at temperatures of up to 60 °C in the presence of minor amounts or absence of water hence indicating that chemical instability of electrolyte components against water is decisive for degradation and an increase in temperature ("thermal aging") just accelerates the degradation impact of water.

CRAFT (complete reduction to amplitude frequency table)--robust and time-efficient Bayesian approach for quantitative mixture analysis by NMR.

PubMed

Krishnamurthy, Krish

2013-12-01

The intrinsic quantitative nature of NMR is increasingly exploited in areas ranging from complex mixture analysis (as in metabolomics and reaction monitoring) to quality assurance/control. Complex NMR spectra are more common than not, and therefore, extraction of quantitative information generally involves significant prior knowledge and/or operator interaction to characterize resonances of interest. Moreover, in most NMR-based metabolomic experiments, the signals from metabolites are normally present as a mixture of overlapping resonances, making quantification difficult. Time-domain Bayesian approaches have been reported to be better than conventional frequency-domain analysis at identifying subtle changes in signal amplitude. We discuss an approach that exploits Bayesian analysis to achieve a complete reduction to amplitude frequency table (CRAFT) in an automated and time-efficient fashion - thus converting the time-domain FID to a frequency-amplitude table. CRAFT uses a two-step approach to FID analysis. First, the FID is digitally filtered and downsampled to several sub FIDs, and secondly, these sub FIDs are then modeled as sums of decaying sinusoids using the Bayesian approach. CRAFT tables can be used for further data mining of quantitative information using fingerprint chemical shifts of compounds of interest and/or statistical analysis of modulation of chemical quantity in a biological study (metabolomics) or process study (reaction monitoring) or quality assurance/control. The basic principles behind this approach as well as results to evaluate the effectiveness of this approach in mixture analysis are presented. Copyright © 2013 John Wiley & Sons, Ltd.

40 CFR 258.54 - Detection monitoring program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.54 Detection... reaction products in the unsaturated zone beneath the MSWLF unit; (iii) The detectability of indicator parameters, waste constituents, and reaction products in the ground water; and (iv) The concentration or...

Micro-view-cell for phase behaviour and in situ Raman analysis of heterogeneously catalysed CO2 hydrogenation

NASA Astrophysics Data System (ADS)

Reymond, Helena; Rudolf von Rohr, Philipp

2017-11-01

The operando study of CO2 hydrogenation is fundamental for a more rational optimisation of heterogeneous catalyst and reactor designs. To further complement the established efficiency of microreactors in reaction screening and bridge the operating and optical gaps, a micro-view-cell is presented for Raman microscopy at extreme conditions with minimum flow interference for genuine reaction analysis. Based on a flat sapphire window unit sealed in a plug flow-type enclosure holding the sample, the cell features unique 14 mm working distance and 0.36 numerical aperture and resists 400 °C and 500 bars. The use of the cell as an in situ tool for fast process monitoring and surface catalyst characterisation is demonstrated with phase behaviour and chemical analysis of the methanol synthesis over a commercial Cu/ZnO/Al2O3 catalyst.

Digitally enhanced thin layer chromatography: further development and some applications in isotopic chemistry.

PubMed

Manthorpe, Daniel P; Lockley, William J S

2013-09-01

Improvements to thin layer chromatography (TLC) analysis can be made easily and cheaply by the application of digital colour photography and image analysis. The combined technique, digitally enhanced TLC (DE-TLC), is applicable to the accurate quantification of analytes in mixtures, to reaction monitoring and to other typical uses of TLC. Examples are given of the application of digitally enhanced TLC to: the deuteromethylations of theophylline to [methyl-(2)H3]caffeine and of umbelliferone to [(2)H3]7-methoxycoumarin; the selection of tertiary amine bases in deuterodechlorination reactions; stoichiometry optimisation in the borodeuteride reduction of quinizarin (1,4-dihydroxyanthraquinone) and to the assessment of xanthophyll yields in Lepidium sativum seedlings grown in deuterated media. Copyright © 2013 John Wiley & Sons, Ltd.

Sulfur Radical-Induced Redox Modifications in Proteins: Analysis and Mechanistic Aspects.

PubMed

Schöneich, Christian

2017-03-10

The sulfur-containing amino acids cysteine (Cys) and methionine (Met) are prominent protein targets of redox modification during conditions of oxidative stress. Here, two-electron pathways have received widespread attention, in part due to their role in signaling processes. However, Cys and Met are equally prone to one-electron pathways, generating intermediary radicals and/or radial ions. These radicals/radical ions can generate various reaction products that are not commonly monitored in redox proteomic studies, but they may be relevant for the fate of proteins during oxidative stress. Recent Advances: Time-resolved kinetic studies and product analysis have expanded our mechanistic understanding of radical reaction pathways of sulfur-containing amino acids. These reactions are now studied in some detail for Met and Cys in proteins, and homocysteine (Hcy) chemically linked to proteins, and the role of protein radical reactions in physiological processes is evolving. Radical-derived products from Cys, Hcy, and Met can react with additional amino acids in proteins, leading to secondary protein modifications, which are potentially remote from initial points of radical attack. These products may contain intra- and intermolecular cross-links, which may lead to protein aggregation. Protein sequence and conformation will have a significant impact on the formation of such products, and a thorough understanding of reaction mechanisms and specifically how protein structure influences reaction pathways will be critical for identification and characterization of novel reaction products. Future studies must evaluate the biological significance of novel reaction products that are derived from radical reactions of sulfur-containing amino acids. Antioxid. Redox Signal. 26, 388-405.

Biosensor-based real-time monitoring of paracetamol photocatalytic degradation.

PubMed

Calas-Blanchard, Carole; Istamboulié, Georges; Bontoux, Margot; Plantard, Gaël; Goetz, Vincent; Noguer, Thierry

2015-07-01

This paper presents for the first time the integration of a biosensor for the on-line, real-time monitoring of a photocatalytic degradation process. Paracetamol was used as a model molecule due to its wide use and occurrence in environmental waters. The biosensor was developed based on tyrosinase immobilization in a polyvinylalcohol photocrosslinkable polymer. It was inserted in a computer-controlled flow system installed besides a photocatalytic reactor including titanium dioxide (TiO2) as photocatalyst. It was shown that the biosensor was able to accurately monitor the paracetamol degradation with time. Compared with conventional HPLC analysis, the described device provides a real-time information on the reaction advancement, allowing a better control of the photodegradation process. Copyright © 2015 Elsevier Ltd. All rights reserved.

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

USDA-ARS?s Scientific Manuscript database

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

Mushroom Tyrosinase: A Model System to Combine Experimental Investigation of Enzyme-Catalyzed Reactions, Data Handling Using R, and Enzyme-Inhibitor Structural Studies

ERIC Educational Resources Information Center

Nairn, Robert; Cresswell, Will; Nairn, Jacqueline

2015-01-01

The activity of mushroom tyrosinase can be measured by monitoring the conversion of phenolic compounds into quinone derivatives using spectrophotometry. This article describes a series of experiments which characterize the functional properties of tyrosinase, the analysis of the resulting data using R to determine the kinetic parameters, and the…

Development of Diagnostic Biomarkers for Detecting Diabetic Retinopathy at Early Stages Using Quantitative Proteomics

PubMed Central

Min, Hophil; Kim, Sang Jin; Oh, Sohee; Kim, Kyunggon; Yu, Hyeong Gon; Park, Taesung; Kim, Youngsoo

2016-01-01

Diabetic retinopathy (DR) is a common microvascular complication caused by diabetes mellitus (DM) and is a leading cause of vision impairment and loss among adults. Here, we performed a comprehensive proteomic analysis to discover biomarkers for DR. First, to identify biomarker candidates that are specifically expressed in human vitreous, we performed data-mining on both previously published DR-related studies and our experimental data; 96 proteins were then selected. To confirm and validate the selected biomarker candidates, candidates were selected, confirmed, and validated using plasma from diabetic patients without DR (No DR) and diabetics with mild or moderate nonproliferative diabetic retinopathy (Mi or Mo NPDR) using semiquantitative multiple reaction monitoring (SQ-MRM) and stable-isotope dilution multiple reaction monitoring (SID-MRM). Additionally, we performed a multiplex assay using 15 biomarker candidates identified in the SID-MRM analysis, which resulted in merged AUC values of 0.99 (No DR versus Mo NPDR) and 0.93 (No DR versus Mi and Mo NPDR). Although further validation with a larger sample size is needed, the 4-protein marker panel (APO4, C7, CLU, and ITIH2) could represent a useful multibiomarker model for detecting the early stages of DR. PMID:26665153

MRMPROBS: a data assessment and metabolite identification tool for large-scale multiple reaction monitoring based widely targeted metabolomics.

PubMed

Tsugawa, Hiroshi; Arita, Masanori; Kanazawa, Mitsuhiro; Ogiwara, Atsushi; Bamba, Takeshi; Fukusaki, Eiichiro

2013-05-21

We developed a new software program, MRMPROBS, for widely targeted metabolomics by using the large-scale multiple reaction monitoring (MRM) mode. The strategy became increasingly popular for the simultaneous analysis of up to several hundred metabolites at high sensitivity, selectivity, and quantitative capability. However, the traditional method of assessing measured metabolomics data without probabilistic criteria is not only time-consuming but is often subjective and makeshift work. Our program overcomes these problems by detecting and identifying metabolites automatically, by separating isomeric metabolites, and by removing background noise using a probabilistic score defined as the odds ratio from an optimized multivariate logistic regression model. Our software program also provides a user-friendly graphical interface to curate and organize data matrices and to apply principal component analyses and statistical tests. For a demonstration, we conducted a widely targeted metabolome analysis (152 metabolites) of propagating Saccharomyces cerevisiae measured at 15 time points by gas and liquid chromatography coupled to triple quadrupole mass spectrometry. MRMPROBS is a useful and practical tool for the assessment of large-scale MRM data available to any instrument or any experimental condition.

Quantitative Analysis of Tissue Samples by Combining iTRAQ Isobaric Labeling with Selected/Multiple Reaction Monitoring (SRM/MRM).

PubMed

Narumi, Ryohei; Tomonaga, Takeshi

2016-01-01

Mass spectrometry-based phosphoproteomics is an indispensible technique used in the discovery and quantification of phosphorylation events on proteins in biological samples. The application of this technique to tissue samples is especially useful for the discovery of biomarkers as well as biological studies. We herein describe the application of a large-scale phosphoproteome analysis and SRM/MRM-based quantitation to develop a strategy for the systematic discovery and validation of biomarkers using tissue samples.

Sequential injection analysis with chemiluminescence detection for rapid monitoring of commercial Calendula officinalis extractions.

PubMed

Hughes, Rachel R; Scown, David; Lenehan, Claire E

2015-01-01

Plant extracts containing high levels of antioxidants are desirable due to their reported health benefits. Most techniques capable of determining the antioxidant activity of plant extracts are unsuitable for rapid at-line analysis as they require extensive sample preparation and/or long analysis times. Therefore, analytical techniques capable of real-time or pseudo real-time at-line monitoring of plant extractions, and determination of extraction endpoints, would be useful to manufacturers of antioxidant-rich plant extracts. To develop a reliable method for the rapid at-line extraction monitoring of antioxidants in plant extracts. Calendula officinalis extracts were prepared from dried flowers and analysed for antioxidant activity using sequential injection analysis (SIA) with chemiluminescence (CL) detection. The intensity of CL emission from the reaction of acidic potassium permanganate with antioxidants within the extract was used as the analytical signal. The SIA-CL method was applied to monitor the extraction of C. officinalis over the course of a batch extraction to determine the extraction endpoint. Results were compared with those from ultra high performance liquid chromatography (UHPLC). Pseudo real-time, at-line monitoring showed the level of antioxidants in a batch extract of Calendula officinalis plateaued after 100 min of extraction. These results correlated well with those of an offline UHPLC study. SIA-CL was found to be a suitable method for pseudo real-time monitoring of plant extractions and determination of extraction endpoints with respect to antioxidant concentrations. The method was applied at-line in the manufacturing industry. Copyright © 2015 John Wiley & Sons, Ltd.

Changes in Effective Thermal Conductivity During the Carbothermic Reduction of Magnetite Using Graphite

NASA Astrophysics Data System (ADS)

Kiamehr, Saeed; Ahmed, Hesham; Viswanathan, Nurni; Seetharaman, Seshadri

2017-06-01

Knowledge of the effective thermal diffusivity changes of systems undergoing reactions where heat transfer plays an important role in the reaction kinetics is essential for process understanding and control. Carbothermic reduction process of magnetite containing composites is a typical example of such systems. The reduction process in this case is highly endothermic and hence, the overall rate of the reaction is greatly influenced by the heat transfer through composite compact. Using Laser-Flash method, the change of effective thermal diffusivity of magnetite-graphite composite pellet was monitored in the dynamic mode over a pre-defined thermal cycle (heating at the rate of 7 K/min to 1423 K (1150 °C), holding the sample for 270 minutes at this temperature and then cooling it down to the room temperature at the same rate as heating). These measurements were supplemented by Thermogravimetric Analysis under comparable experimental conditions as well as quenching tests of the samples in order to combine the impact of various factors such as sample dilatations and changes in apparent density on the progress of the reaction. The present results show that monitoring thermal diffusivity changes during the course of reduction would be a very useful tool in a total understanding of the underlying physicochemical phenomena. At the end, effort is made to estimate the apparent thermal conductivity values based on the measured thermal diffusivity and dilatations.

Increased Depth and Breadth of Plasma Protein Quantitation via Two-Dimensional Liquid Chromatography/Multiple Reaction Monitoring-Mass Spectrometry with Labeled Peptide Standards.

PubMed

Percy, Andrew J; Yang, Juncong; Chambers, Andrew G; Borchers, Christoph H

2016-01-01

Absolute quantitative strategies are emerging as a powerful and preferable means of deriving concentrations in biological samples for systems biology applications. Method development is driven by the need to establish new-and validate current-protein biomarkers of high-to-low abundance for clinical utility. In this chapter, we describe a methodology involving two-dimensional (2D) reversed-phase liquid chromatography (RPLC), operated under alkaline and acidic pH conditions, combined with multiple reaction monitoring (MRM)-mass spectrometry (MS) (also called selected reaction monitoring (SRM)-MS) and a complex mixture of stable isotope-labeled standard (SIS) peptides, to quantify a broad and diverse panel of 253 proteins in human blood plasma. The quantitation range spans 8 orders of magnitude-from 15 mg/mL (for vitamin D-binding protein) to 450 pg/mL (for protein S100-B)-and includes 31 low-abundance proteins (defined as being <10 ng/mL) of potential disease relevance. The method is designed to assess candidates at the discovery and/or verification phases of the biomarker pipeline and can be adapted to examine smaller or alternate panels of proteins for higher sample throughput. Also detailed here is the application of our recently developed software tool-Qualis-SIS-for protein quantitation (via regression analysis of standard curves) and quality assessment of the resulting data. Overall, this chapter provides the blueprint for the replication of this quantitative proteomic method by proteomic scientists of all skill levels.

A reliable and rapid tool for plasma quantification of 18 psychotropic drugs by ESI tandem mass spectrometry.

PubMed

Vecchione, Gennaro; Casetta, Bruno; Chiapparino, Antonella; Bertolino, Alessandro; Tomaiuolo, Michela; Cappucci, Filomena; Gatta, Raffaella; Margaglione, Maurizio; Grandone, Elvira

2012-01-01

A simple liquid chromatographic tandem mass spectrometry (LC-MS/MS) method has been developed for simultaneous analysis of 17 basic and one acid psychotropic drugs in human plasma. The method relies on a protein precipitation step for sample preparation and offers high sensitivity, wide linearity without interferences from endogenous matrix components. Chromatography was run on a reversed-phase column with an acetonitrile-H₂O mixture. The quantification of target compounds was performed in multiple reaction monitoring (MRM) and by switching the ionization polarity within the analytical run. A further sensitivity increase was obtained by implementing the functionality "scheduled multiple reaction monitoring" (sMRM) offered by the recent version of the software package managing the instrument. The overall injection interval was less than 5.5 min. Regression coefficients of the calibration curves and limits of quantification (LOQ) showed a good coverage of over-therapeutic, therapeutic and sub-therapeutic ranges. Recovery rates, measured as percentage of recovery of spiked plasma samples, were ≥ 94%. Precision and accuracy data have been satisfactory for a therapeutic drug monitoring (TDM) service as for managing plasma samples from patients receiving psycho-pharmacological treatment. Copyright © 2012 Elsevier B.V. All rights reserved.

Range of protein detection by selected/multiple reaction monitoring mass spectrometry in an unfractionated human cell culture lysate.

PubMed

Ebhardt, H Alexander; Sabidó, Eduard; Hüttenhain, Ruth; Collins, Ben; Aebersold, Ruedi

2012-04-01

Selected or multiple reaction monitoring is a targeted mass spectrometry method (S/MRM-MS), in which many peptides are simultaneously and consistently analyzed during a single liquid chromatography-mass spectrometry (LC-S/MRM-MS) measurement. These capabilities make S/MRM-MS an attractive method to monitor a consistent set of proteins over various experimental conditions. To increase throughput for S/MRM-MS it is advantageous to use scheduled methods and unfractionated protein extracts. Here, we established the practically measurable dynamic range of proteins reliably detectable and quantifiable in an unfractionated protein extract from a human cell line using LC-S/MRM-MS. Initially, we analyzed S/MRM transition peak groups in terms of interfering signals and compared S/MRM transition peak groups to MS1-triggered MS2 spectra using dot-product analysis. Finally, using unfractionated protein extract from human cell lysate, we quantified the upper boundary of copies per cell to be 35 million copies per cell, while 7500 copies per cell represents a lower boundary using a single 35 min linear gradient LC-S/MRM-MS measurement on a current, standard commercial instrument. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

PTR-MS in Italy: A Multipurpose Sensor with Applications in Environmental, Agri-Food and Health Science

PubMed Central

Cappellin, Luca; Loreto, Francesco; Aprea, Eugenio; Romano, Andrea; del Pulgar, José Sánchez; Gasperi, Flavia; Biasioli, Franco

2013-01-01

Proton Transfer Reaction Mass Spectrometry (PTR-MS) has evolved in the last decade as a fast and high sensitivity sensor for the real-time monitoring of volatile compounds. Its applications range from environmental sciences to medical sciences, from food technology to bioprocess monitoring. Italian scientists and institutions participated from the very beginning in fundamental and applied research aiming at exploiting the potentialities of this technique and providing relevant methodological advances and new fundamental indications. In this review we describe this activity on the basis of the available literature. The Italian scientific community has been active mostly in food science and technology, plant physiology and environmental studies and also pioneered the applications of the recently released PTR-ToF-MS (Proton Transfer Reaction-Time of Flight-Mass Spectrometry) in food science and in plant physiology. In the very last years new results related to bioprocess monitoring and health science have been published as well. PTR-MS data analysis, particularly in the case of the ToF based version, and the application of advanced chemometrics and data mining are also aspects characterising the activity of the Italian community. PMID:24021966

Accurate Quantification of Cardiovascular Biomarkers in Serum Using Protein Standard Absolute Quantification (PSAQ™) and Selected Reaction Monitoring*

PubMed Central

Huillet, Céline; Adrait, Annie; Lebert, Dorothée; Picard, Guillaume; Trauchessec, Mathieu; Louwagie, Mathilde; Dupuis, Alain; Hittinger, Luc; Ghaleh, Bijan; Le Corvoisier, Philippe; Jaquinod, Michel; Garin, Jérôme; Bruley, Christophe; Brun, Virginie

2012-01-01

Development of new biomarkers needs to be significantly accelerated to improve diagnostic, prognostic, and toxicity monitoring as well as therapeutic follow-up. Biomarker evaluation is the main bottleneck in this development process. Selected Reaction Monitoring (SRM) combined with stable isotope dilution has emerged as a promising option to speed this step, particularly because of its multiplexing capacities. However, analytical variabilities because of upstream sample handling or incomplete trypsin digestion still need to be resolved. In 2007, we developed the PSAQ™ method (Protein Standard Absolute Quantification), which uses full-length isotope-labeled protein standards to quantify target proteins. In the present study we used clinically validated cardiovascular biomarkers (LDH-B, CKMB, myoglobin, and troponin I) to demonstrate that the combination of PSAQ and SRM (PSAQ-SRM) allows highly accurate biomarker quantification in serum samples. A multiplex PSAQ-SRM assay was used to quantify these biomarkers in clinical samples from myocardial infarction patients. Good correlation between PSAQ-SRM and ELISA assay results was found and demonstrated the consistency between these analytical approaches. Thus, PSAQ-SRM has the capacity to improve both accuracy and reproducibility in protein analysis. This will be a major contribution to efficient biomarker development strategies. PMID:22080464

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

EPA Science Inventory

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...

Action Monitoring and Perfectionism in Anorexia Nervosa

ERIC Educational Resources Information Center

Pieters, Guido L. M.; de Bruijn, Ellen R. A.; Maas, Yvonne; Hulstijn, Wouter; Vandereycken, Walter; Peuskens, Joseph; Sabbe, Bernard G.

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 times, error rates, and the error-related negativity ERP…

A real-time data-acquisition and analysis system with distributed UNIX workstations

NASA Astrophysics Data System (ADS)

Yamashita, H.; Miyamoto, K.; Maruyama, K.; Hirosawa, H.; Nakayoshi, K.; Emura, T.; Sumi, Y.

1996-02-01

A compact data-acquisition system using three RISC/UNIX™ workstations (SUN™/SPARCstation™) with real-time capabilities of monitoring and analysis has been developed for the study of photonuclear reactions with the large-acceptance spectrometer TAGX. One workstation acquires data from memory modules in the front-end electronics (CAMAC and TKO) with a maximum speed of 300 Kbytes/s, where data size times instantaneous rate is 1 Kbyte × 300 Hz. Another workstation, which has real-time capability for run monitoring, gets the data with a buffer manager called NOVA. The third workstation analyzes the data and reconstructs the event. In addition to a general hardware and software description, priority settings and run control by shell scripts are described. This system has recently been used successfully in a two month long experiment.

Flow chemistry vs. flow analysis.

PubMed

Trojanowicz, Marek

2016-01-01

The flow mode of conducting chemical syntheses facilitates chemical processes through the use of on-line analytical monitoring of occurring reactions, the application of solid-supported reagents to minimize downstream processing and computerized control systems to perform multi-step sequences. They are exactly the same attributes as those of flow analysis, which has solid place in modern analytical chemistry in several last decades. The following review paper, based on 131 references to original papers as well as pre-selected reviews, presents basic aspects, selected instrumental achievements and developmental directions of a rapidly growing field of continuous flow chemical synthesis. Interestingly, many of them might be potentially employed in the development of new methods in flow analysis too. In this paper, examples of application of flow analytical measurements for on-line monitoring of flow syntheses have been indicated and perspectives for a wider application of real-time analytical measurements have been discussed. Copyright © 2015 Elsevier B.V. All rights reserved.

Development of MRM-based assays for the absolute quantitation of plasma proteins.

PubMed

Kuzyk, Michael A; Parker, Carol E; Domanski, Dominik; Borchers, Christoph H

2013-01-01

Multiple reaction monitoring (MRM), sometimes called selected reaction monitoring (SRM), is a directed tandem mass spectrometric technique performed on to triple quadrupole mass spectrometers. MRM assays can be used to sensitively and specifically quantify proteins based on peptides that are specific to the target protein. Stable-isotope-labeled standard peptide analogues (SIS peptides) of target peptides are added to enzymatic digests of samples, and quantified along with the native peptides during MRM analysis. Monitoring of the intact peptide and a collision-induced fragment of this peptide (an ion pair) can be used to provide information on the absolute peptide concentration of the peptide in the sample and, by inference, the concentration of the intact protein. This technique provides high specificity by selecting for biophysical parameters that are unique to the target peptides: (1) the molecular weight of the peptide, (2) the generation of a specific fragment from the peptide, and (3) the HPLC retention time during LC/MRM-MS analysis. MRM is a highly sensitive technique that has been shown to be capable of detecting attomole levels of target peptides in complex samples such as tryptic digests of human plasma. This chapter provides a detailed description of how to develop and use an MRM protein assay. It includes sections on the critical "first step" of selecting the target peptides, as well as optimization of MRM acquisition parameters for maximum sensitivity of the ion pairs that will be used in the final method, and characterization of the final MRM assay.

Mechanistic Analysis of the C-H Amination Reaction of Menthol by CuBr2 and Selectfluor.

PubMed

Sathyamoorthi, Shyam; Lai, Yin-Hung; Bain, Ryan M; Zare, Richard N

2018-05-18

The mechanism of the Ritter-type C-H amination reaction of menthol with acetonitrile using CuBr 2 , Selectfluor, and Zn(OTf) 2 , first disclosed by Baran and coworkers in 2012, was studied using a combination of online electrospray ionization mass spectrometry, continuous UV/vis spectrometric monitoring, and density functional theory calculations. In addition to corroborating Baran's original mechanistic proposal, these studies uncovered a second pathway to product formation, which likely only occurs in microdroplets. DFT calculations show that neither pathway has a barrier that is greater than 6.8 kcal/mol, suggesting that both mechanisms are potentially operative under ambient conditions.

Generic HPLC platform for automated enzyme reaction monitoring: Advancing the assay toolbox for transaminases and other PLP-dependent enzymes.

PubMed

Börner, Tim; Grey, Carl; Adlercreutz, Patrick

2016-08-01

Methods for rapid and direct quantification of enzyme kinetics independent of the substrate stand in high demand for both fundamental research and bioprocess development. This study addresses the need for a generic method by developing an automated, standardizable HPLC platform monitoring reaction progress in near real-time. The method was applied to amine transaminase (ATA) catalyzed reactions intensifying process development for chiral amine synthesis. Autosampler-assisted pipetting facilitates integrated mixing and sampling under controlled temperature. Crude enzyme formulations in high and low substrate concentrations can be employed. Sequential, small (1 µL) sample injections and immediate detection after separation permits fast reaction monitoring with excellent sensitivity, accuracy and reproducibility. Due to its modular design, different chromatographic techniques, e.g. reverse phase and size exclusion chromatography (SEC) can be employed. A novel assay for pyridoxal 5'-phosphate-dependent enzymes is presented using SEC for direct monitoring of enzyme-bound and free reaction intermediates. Time-resolved changes of the different cofactor states, e.g. pyridoxal 5'-phosphate, pyridoxamine 5'-phosphate and the internal aldimine were traced in both half reactions. The combination of the automated HPLC platform with SEC offers a method for substrate-independent screening, which renders a missing piece in the assay and screening toolbox for ATAs and other PLP-dependent enzymes. Copyright © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Determination of yeast assimilable nitrogen content in wine fermentations by sequential injection analysis with spectrophotometric detetection.

PubMed

Muik, Barbara; Edelmann, Andrea; Lendl, Bernhard; Ayora-Cañada, María José

2002-09-01

An automated method for measuring the primary amino acid concentration in wine fermentations by sequential injection analysis with spectrophotometric detection was developed. Isoindole-derivatives from the primary amino acid were formed by reaction with o-phthaldialdehyde and N-acetyl- L-cysteine and measured at 334 nm with respect to a baseline point at 700 nm to compensate the observed Schlieren effect. As the reaction kinetic was strongly matrix dependent the analytical readout at the final reaction equilibrium has been evaluated. Therefore four parallel reaction coils were included in the flow system to be capable of processing four samples simultaneously. Using isoleucine as the representative primary amino acid in wine fermentations a linear calibration curve from 2 to 10 mM isoleucine, corresponding to 28 to 140 mg nitrogen/L (N/L) was obtained. The coefficient of variation of the method was 1.5% at a throughput of 12 samples per hour. The developed method was successfully used to monitor two wine fermentations during alcoholic fermentation. The results were in agreement with an external reference method based on high performance liquid chromatography. A mean-t-test showed no significant differences between the two methods at a confidence level of 95%.

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

PubMed

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 <2h. An affordable assay utilizing this methodology will facilitate testing for regulatory and safety applications. The work describes for the first time, the Protein 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.

Reactive Tracer Techniques to Quantitatively Monitor Carbon Dioxide Storage in Geologic Formations

NASA Astrophysics Data System (ADS)

Matter, J. M.; Carson, C.; Stute, M.; Broecker, W. S.

2012-12-01

Injection of CO2 into geologic storage reservoirs induces fluid-rock reactions that may lead to the mineralization of the injected CO2. The long-term safety of geologic CO2 storage is, therefore, determined by in situ CO2-fluid-rock reactions. Currently existing monitoring and verification techniques for CO2 storage are insufficient to characterize the solubility and reactivity of the injected CO2, and to establish a mass balance of the stored CO2. Dissolved and chemically transformed CO2 thus avoid detection. We developed and are testing a new reactive tracer technique for quantitative monitoring and detection of dissolved and chemically transformed CO2 in geologic storage reservoirs. The technique involves tagging the injected carbon with radiocarbon (14C). Carbon-14 is a naturally occurring radioisotope produced by cosmic radiation and made artificially by 14N neutron capture. The ambient concentration is very low with a 14C/12C ratio of 10-12. The concentration of 14C in deep geologic formations and fossil fuels is at least two orders of magnitude lower. This makes 14C an ideal quantitative tracer for tagging underground injections of anthropogenic CO2. We are testing the feasibility of this tracer technique at the CarbFix pilot injection site in Iceland, where approximately 2,000 tons of CO2 dissolved in water are currently injected into a deep basalt aquifer. The injected CO2 is tagged with 14C by dynamically adding calibrated amounts of H14CO3 solution to the injection stream. The target concentration is 12 Bq/kg of injected water, which results in a 14C activity that is 5 times enriched compared to the 1850 background. In addition to 14C as a reactive tracer, trifluormethylsulphur pentafluoride (SF5CF3) and sulfurhexafluoride (SF6) are used as conservative tracers to monitor the transport of the injected CO2 in the subsurface. Fluid samples are collected for tracer analysis from the injection and monitoring wells on a regular basis. Results show a fast reaction of the injected CO2 with the ambient reservoir fluid and rocks. Mixing and in situ CO2-water-rock reactions are detected by changes in the different tracer ratios. The feasibility of 14C as a reactive tracer for geologic CO2 storage also depends on the analytical technique used to measure 14C activities. Currently, 14C is analyzed using Accelerator Mass Spectrometery (AMS), which is expensive and requires centralized facilities. To enable real time online monitoring and verification, we are developing an alternative detection method for radiocarbon. The IntraCavity OptoGalvanic Spectroscopy (ICOGS) system is using a CO2 laser to detect carbon isotope ratios at environmental levels. Results from our prototype of this bench-top technology demonstrate that an ICOGS system can be used in a continuous mode with analysis times of the order of minutes, and can deliver data of similar quality as AMS.

Lipase-catalysed acylation of starch and determination of the degree of substitution by methanolysis and GC

PubMed Central

2010-01-01

Background Natural polysaccharides such as starch are becoming increasingly interesting as renewable starting materials for the synthesis of biodegradable polymers using chemical or enzymatic methods. Given the complexity of polysaccharides, the analysis of reaction products is challenging. Results Esterification of starch with fatty acids has traditionally been monitored by saponification and back-titration, but in our experience this method is unreliable. Here we report a novel GC-based method for the fast and reliable quantitative determination of esterification. The method was used to monitor the enzymatic esterification of different starches with decanoic acid, using lipase from Thermomyces lanuginosus. The reaction showed a pronounced optimal water content of 1.25 mL per g starch, where a degree of substitution (DS) of 0.018 was obtained. Incomplete gelatinization probably accounts for lower conversion with less water. Conclusions Lipase-catalysed esterification of starch is feasible in aqueous gel systems, but attention to analytical methods is important to obtain correct DS values. PMID:21114817

Measurement of 235U(n,n'γ) and 235U(n,2nγ) reaction cross sections

NASA Astrophysics Data System (ADS)

Kerveno, M.; Thiry, J. C.; Bacquias, A.; Borcea, C.; Dessagne, P.; Drohé, J. C.; Goriely, S.; Hilaire, S.; Jericha, E.; Karam, H.; Negret, A.; Pavlik, A.; Plompen, A. J. M.; Romain, P.; Rouki, C.; Rudolf, G.; Stanoiu, M.

2013-02-01

The design of generation IV nuclear reactors and the studies of new fuel cycles require knowledge of the cross sections of various nuclear reactions. Our research is focused on (n,xnγ) reactions occurring in these new reactors. The aim is to measure unknown cross sections and to reduce the uncertainty on present data for reactions and isotopes of interest for transmutation or advanced reactors. The present work studies the 235U(n,n'γ) and 235U(n,2nγ) reactions in the fast neutron energy domain (up to 20 MeV). The experiments were performed with the Geel electron linear accelerator GELINA, which delivers a pulsed white neutron beam. The time characteristics enable measuring neutron energies with the time-of-flight (TOF) technique. The neutron induced reactions [in this case inelastic scattering and (n,2n) reactions] are identified by on-line prompt γ spectroscopy with an experimental setup including four high-purity germanium (HPGe) detectors. A fission ionization chamber is used to monitor the incident neutron flux. The experimental setup and analysis methods are presented and the model calculations performed with the TALYS-1.2 code are discussed.

A Database of Reaction Monitoring Mass Spectrometry Assays for Elucidating Therapeutic Response in Cancer

PubMed Central

Remily-Wood, Elizabeth R.; Liu, Richard Z.; Xiang, Yun; Chen, Yi; Thomas, C. Eric; Rajyaguru, Neal; Kaufman, Laura M.; Ochoa, Joana E.; Hazlehurst, Lori; Pinilla-Ibarz, Javier; Lancet, Jeffrey; Zhang, Guolin; Haura, Eric; Shibata, David; Yeatman, Timothy; Smalley, Keiran S.M.; Dalton, William S.; Huang, Emina; Scott, Ed; Bloom, Gregory C.; Eschrich, Steven A.; Koomen, John M.

2012-01-01

Purpose The Quantitative Assay Database (QuAD), http://proteome.moffitt.org/QUAD/, facilitates widespread implementation of quantitative mass spectrometry in cancer biology and clinical research through sharing of methods and reagents for monitoring protein expression and modification. Experimental Design Liquid chromatography coupled to multiple reaction monitoring mass spectrometry (LC-MRM) assays are developed using SDS-PAGE fractionated lysates from cancer cell lines. Pathway maps created using GeneGO Metacore provide the biological relationships between proteins and illustrate concepts for multiplexed analysis; each protein can be selected to examine assay development at the protein and peptide level. Results The coupling of SDS-PAGE and LC-MRM screening has been used to detect 876 peptides from 218 cancer-related proteins in model systems including colon, lung, melanoma, leukemias, and myeloma, which has led to the development of 95 quantitative assays including stable-isotope labeled peptide standards. Methods are published online and peptide standards are made available to the research community. Protein expression measurements for heat shock proteins, including a comparison with ELISA and monitoring response to the HSP90 inhibitor, 17-DMAG, are used to illustrate the components of the QuAD and its potential utility. Conclusions and Clinical Relevance This resource enables quantitative assessment of protein components of signaling pathways and biological processes and holds promise for systematic investigation of treatment responses in cancer. PMID:21656910

Live single cell functional phenotyping in droplet nano-liter reactors

NASA Astrophysics Data System (ADS)

Konry, Tania; Golberg, Alexander; Yarmush, Martin

2013-11-01

While single cell heterogeneity is present in all biological systems, most studies cannot address it due to technical limitations. Here we describe a nano-liter droplet microfluidic-based approach for stimulation and monitoring of surfaceand secreted markers of live single immune dendritic cells (DCs) as well as monitoring the live T cell/DC interaction. This nano-liter in vivo simulating microenvironment allows delivering various stimuli reagents to each cell and appropriate gas exchanges which are necessary to ensure functionality and viability of encapsulated cells. Labeling bioassay and microsphere sensors were integrated into nano-liter reaction volume of the droplet to monitor live single cell surface markers and secretion analysis in the time-dependent fashion. Thus live cell stimulation, secretion and surface monitoring can be obtained simultaneously in distinct microenvironment, which previously was possible using complicated and multi-step in vitro and in vivo live-cell microscopy, together with immunological studies of the outcome secretion of cellular function.

Planning for execution monitoring on a planetary rover

NASA Technical Reports Server (NTRS)

Gat, Erann; Firby, R. James; Miller, David P.

1990-01-01

A planetary rover will be traversing largely unknown and often unknowable terrain. In addition to geometric obstacles such as cliffs, rocks, and holes, it may also have to deal with non-geometric hazards such as soft soil and surface breakthroughs which often cannot be detected until rover is in imminent danger. Therefore, the rover must monitor its progress throughout a traverse, making sure to stay on course and to detect and act on any previously unseen hazards. Its onboard planning system must decide what sensors to monitor, what landmarks to take position readings from, and what actions to take if something should go wrong. The planning systems being developed for the Pathfinder Planetary Rover to perform these execution monitoring tasks are discussed. This system includes a network of planners to perform path planning, expectation generation, path analysis, sensor and reaction selection, and resource allocation.

Characterization of cure kinetics and physical properties of a high performance, glass fiber-reinforced epoxy prepreg and a novel fluorine-modified, amine-cured commercial epoxy

NASA Astrophysics Data System (ADS)

Bilyeu, Bryan

Kinetic equation parameters for the curing reaction of a commercial glass fiber reinforced high performance epoxy prepreg composed of the tetrafunctional epoxy tetraglycidyl 4,4-diaminodiphenyl methane (TGDDM), the tetrafunctional amine curing agent 4,4'-diaminodiphenylsulfone (DDS) and an ionic initiator/accelerator, are determined by various thermal analysis techniques and the results compared. The reaction is monitored by heat generated determined by differential scanning calorimetry (DSC) and by high speed DSC when the reaction rate is high. The changes in physical properties indicating increasing conversion are followed by shifts in glass transition temperature determined by DSC, temperature-modulated DSC (TMDSC), step scan DSC and high speed DSC, thermomechanical (TMA) and dynamic mechanical (DMA) analysis and thermally stimulated depolarization (TSD). Changes in viscosity, also indicative of degree of conversion, are monitored by DMA. Thermal stability as a function of degree of cure is monitored by thermogravimetric analysis (TGA). The parameters of the general kinetic equations, including activation energy and rate constant, are explained and used to compare results of various techniques. The utilities of the kinetic descriptions are demonstrated in the construction of a useful time-temperature-transformation (TTT) diagram and a continuous heating transformation (CHT) diagram for rapid determination of processing parameters in the processing of prepregs. Shrinkage due to both resin consolidation and fiber rearrangement is measured as the linear expansion of the piston on a quartz dilatometry cell using TMA. The shrinkage of prepregs was determined to depend on the curing temperature, pressure applied and the fiber orientation. Chemical modification of an epoxy was done by mixing a fluorinated aromatic amine (aniline) with a standard aliphatic amine as a curing agent for a commercial Diglycidylether of Bisphenol-A (DGEBA) epoxy. The resulting cured network was tested for wear resistance using tribological techniques. Of the six anilines, 3-fluoroaniline and 4-fluoroaniline were determined to have lower wear than the unmodified epoxy, while the others showed much higher wear rates.

Modular radiochemistry synthesis system

DOEpatents

Satyamurthy, Nagichettiar; Barrio, Jorge R.; Amarasekera, Bernard; Van Dam, Michael R.; Olma, Sebastian; Williams, Dirk; Eddings, Mark; Shen, Clifton Kwang-Fu

2016-11-01

A modular chemical production system includes multiple modules for performing a chemical reaction, particularly of radiochemical compounds, from a remote location. One embodiment comprises a reaction vessel including a moveable heat source with the position thereof relative to the reaction vessel being controllable from a remote position. Alternatively the heat source may be fixed in location and the reaction vial is moveable into and out of the heat source. The reaction vessel has one or more sealing plugs, the positioning of which in relationship to the reaction vessel is controllable from a remote position. Also the one or more reaction vessel sealing plugs can include one or more conduits there through for delivery of reactants, gases at atmospheric or an elevated pressure, inert gases, drawing a vacuum and removal of reaction end products to and from the reaction vial, the reaction vial with sealing plug in position being operable at elevated pressures. The modular chemical production system is assembled from modules which can each include operating condition sensors and controllers configured for monitoring and controlling the individual modules and the assembled system from a remote position. Other modules include, but are not limited to a Reagent Storage and Delivery Module, a Cartridge Purification Module, a Microwave Reaction Module, an External QC/Analysis/Purification Interface Module, an Aliquotting Module, an F-18 Drying Module, a Concentration Module, a Radiation Counting Module, and a Capillary Reactor Module.

Modular radiochemistry synthesis system

DOEpatents

Satyamurthy, Nagichettiar; Barrio, Jorge R.; Amarasekera, Bernard; Van Dam, R. Michael; Olma, Sebastian; Williams, Dirk; Eddings, Mark; Shen, Clifton Kwang-Fu

2015-12-15

A modular chemical production system includes multiple modules for performing a chemical reaction, particularly of radiochemical compounds, from a remote location. One embodiment comprises a reaction vessel including a moveable heat source with the position thereof relative to the reaction vessel being controllable from a remote position. Alternatively the heat source may be fixed in location and the reaction vial is moveable into and out of the heat source. The reaction vessel has one or more sealing plugs, the positioning of which in relationship to the reaction vessel is controllable from a remote position. Also the one or more reaction vessel sealing plugs can include one or more conduits there through for delivery of reactants, gases at atmospheric or an elevated pressure, inert gases, drawing a vacuum and removal of reaction end products to and from the reaction vial, the reaction vial with sealing plug in position being operable at elevated pressures. The modular chemical production system is assembled from modules which can each include operating condition sensors and controllers configured for monitoring and controlling the individual modules and the assembled system from a remote position. Other modules include, but are not limited to a Reagent Storage and Delivery Module, a Cartridge Purification Module, a Microwave Reaction Module, an External QC/Analysis/Purification Interface Module, an Aliquotting Module, an F-18 Drying Module, a Concentration Module, a Radiation Counting Module, and a Capillary Reactor Module.

Modular radiochemistry synthesis system

DOEpatents

Satyamurthy, Nagichettiar; Barrio, Jorge R; Amarasekera, Bernard; Van Dam, R. Michael; Olma, Sebastian; Williams, Dirk; Eddings, Mark A; Shen, Clifton Kwang-Fu

2015-02-10

A modular chemical production system includes multiple modules for performing a chemical reaction, particularly of radiochemical compounds, from a remote location. One embodiment comprises a reaction vessel including a moveable heat source with the position thereof relative to the reaction vessel being controllable from a remote position. Alternatively the heat source may be fixed in location and the reaction vial is moveable into and out of the heat source. The reaction vessel has one or more sealing plugs, the positioning of which in relationship to the reaction vessel is controllable from a remote position. Also the one or more reaction vessel sealing plugs can include one or more conduits there through for delivery of reactants, gases at atmospheric or an elevated pressure, inert gases, drawing a vacuum and removal of reaction end products to and from the reaction vial, the reaction vial with sealing plug in position being operable at elevated pressures. The modular chemical production system is assembled from modules which can each include operating condition sensors and controllers configured for monitoring and controlling the individual modules and the assembled system from a remote position. Other modules include, but are not limited to a Reagent Storage and Delivery Module, a Cartridge Purification Module, a Microwave Reaction Module, an External QC/Analysis/Purification Interface Module, an Aliquotting Module, an F-18 Drying Module, a Concentration Module, a Radiation Counting Module, and a Capillary Reactor Module.

Optimized protocol for quantitative multiple reaction monitoring-based proteomic analysis of formalin-fixed, paraffin embedded tissues

PubMed Central

Kennedy, Jacob J.; Whiteaker, Jeffrey R.; Schoenherr, Regine M.; Yan, Ping; Allison, Kimberly; Shipley, Melissa; Lerch, Melissa; Hoofnagle, Andrew N.; Baird, Geoffrey Stuart; Paulovich, Amanda G.

2016-01-01

Despite a clinical, economic, and regulatory imperative to develop companion diagnostics, precious few new biomarkers have been successfully translated into clinical use, due in part to inadequate protein assay technologies to support large-scale testing of hundreds of candidate biomarkers in formalin-fixed paraffin embedded (FFPE) tissues. While the feasibility of using targeted, multiple reaction monitoring-mass spectrometry (MRM-MS) for quantitative analyses of FFPE tissues has been demonstrated, protocols have not been systematically optimized for robust quantification across a large number of analytes, nor has the performance of peptide immuno-MRM been evaluated. To address this gap, we used a test battery approach coupled to MRM-MS with the addition of stable isotope labeled standard peptides (targeting 512 analytes) to quantitatively evaluate the performance of three extraction protocols in combination with three trypsin digestion protocols (i.e. 9 processes). A process based on RapiGest buffer extraction and urea-based digestion was identified to enable similar quantitation results from FFPE and frozen tissues. Using the optimized protocols for MRM-based analysis of FFPE tissues, median precision was 11.4% (across 249 analytes). There was excellent correlation between measurements made on matched FFPE and frozen tissues, both for direct MRM analysis (R2 = 0.94) and immuno-MRM (R2 = 0.89). The optimized process enables highly reproducible, multiplex, standardizable, quantitative MRM in archival tissue specimens. PMID:27462933

Establishing a reliable multiple reaction monitoring-based method for the quantification of obesity-associated comorbidities in serum and adipose tissue requires intensive clinical validation.

PubMed

Oberbach, Andreas; Schlichting, Nadine; Neuhaus, Jochen; Kullnick, Yvonne; Lehmann, Stefanie; Heinrich, Marco; Dietrich, Arne; Mohr, Friedrich Wilhelm; von Bergen, Martin; Baumann, Sven

2014-12-05

Multiple reaction monitoring (MRM)-based mass spectrometric quantification of peptides and their corresponding proteins has been successfully applied for biomarker validation in serum. The option of multiplexing offers the chance to analyze various proteins in parallel, which is especially important in obesity research. Here, biomarkers that reflect multiple comorbidities and allow monitoring of therapy outcomes are required. Besides the suitability of established MRM assays for serum protein quantification, it is also feasible for analysis of tissues secreting the markers of interest. Surprisingly, studies comparing MRM data sets with established methods are rare, and therefore the biological and clinical value of most analytes remains questionable. A MRM method using nano-UPLC-MS/MS for the quantification of obesity related surrogate markers for several comorbidities in serum, plasma, visceral and subcutaneous adipose tissue was established. Proteotypic peptides for complement C3, adiponectin, angiotensinogen, and plasma retinol binding protein (RBP4) were quantified using isotopic dilution analysis and compared to the standard ELISA method. MRM method variabilities were mainly below 10%. The comparison with other MS-based approaches showed a good correlation. However, large differences in absolute quantification for complement C3 and adiponectin were obtained compared to ELISA, while less marked differences were observed for angiotensinogen and RBP4. The verification of MRM in obesity was performed to discriminate first lean and obese phenotype and second to monitor excessive weight loss after gastric bypass surgery in a seven-month follow-up. The presented MRM assay was able to discriminate obese phenotype from lean and monitor weight loss related changes of surrogate markers. However, inclusion of additional biomarkers was necessary to interpret the MRM data on obesity phenotype properly. In summary, the development of disease-related MRMs should include a step of matching the MRM data with clinically approved standard methods and defining reference values in well-sized representative age, gender, and disease-matched cohorts.

Employing Magnetic Levitation to Monitor Reaction Kinetics and Measure Activation Energy

ERIC Educational Resources Information Center

Benz, Lauren; Cesafsky, Karen E.; Le, Tran; Park, Aileen; Malicky, David

2012-01-01

This article describes a simple and inexpensive undergraduate-level kinetics experiment that uses magnetic levitation to monitor the progress and determine the activation energy of a condensation reaction on a polymeric solid support. The method employs a cuvette filled with a paramagnetic solution positioned between two strong magnets. The…

Monitoring lipase/esterase activity by stopped flow in a sequential injection analysis system using p-nitrophenyl butyrate.

PubMed

Pliego, Jorge; Mateos, Juan Carlos; Rodriguez, Jorge; Valero, Francisco; Baeza, Mireia; Femat, Ricardo; Camacho, Rosa; Sandoval, Georgina; Herrera-López, Enrique J

2015-01-27

Lipases and esterases are biocatalysts used at the laboratory and industrial level. To obtain the maximum yield in a bioprocess, it is important to measure key variables, such as enzymatic activity. The conventional method for monitoring hydrolytic activity is to take out a sample from the bioreactor to be analyzed off-line at the laboratory. The disadvantage of this approach is the long time required to recover the information from the process, hindering the possibility to develop control systems. New strategies to monitor lipase/esterase activity are necessary. In this context and in the first approach, we proposed a lab-made sequential injection analysis system to analyze off-line samples from shake flasks. Lipase/esterase activity was determined using p-nitrophenyl butyrate as the substrate. The sequential injection analysis allowed us to measure the hydrolytic activity from a sample without dilution in a linear range from 0.05-1.60 U/mL, with the capability to reach sample dilutions up to 1000 times, a sampling frequency of five samples/h, with a kinetic reaction of 5 min and a relative standard deviation of 8.75%. The results are promising to monitor lipase/esterase activity in real time, in which optimization and control strategies can be designed.

Monitoring Lipase/Esterase Activity by Stopped Flow in a Sequential Injection Analysis System Using p-Nitrophenyl Butyrate

PubMed Central

Pliego, Jorge; Mateos, Juan Carlos; Rodriguez, Jorge; Valero, Francisco; Baeza, Mireia; Femat, Ricardo; Camacho, Rosa; Sandoval, Georgina; Herrera-López, Enrique J.

2015-01-01

Lipases and esterases are biocatalysts used at the laboratory and industrial level. To obtain the maximum yield in a bioprocess, it is important to measure key variables, such as enzymatic activity. The conventional method for monitoring hydrolytic activity is to take out a sample from the bioreactor to be analyzed off-line at the laboratory. The disadvantage of this approach is the long time required to recover the information from the process, hindering the possibility to develop control systems. New strategies to monitor lipase/esterase activity are necessary. In this context and in the first approach, we proposed a lab-made sequential injection analysis system to analyze off-line samples from shake flasks. Lipase/esterase activity was determined using p-nitrophenyl butyrate as the substrate. The sequential injection analysis allowed us to measure the hydrolytic activity from a sample without dilution in a linear range from 0.05–1.60 U/mL, with the capability to reach sample dilutions up to 1000 times, a sampling frequency of five samples/h, with a kinetic reaction of 5 min and a relative standard deviation of 8.75%. The results are promising to monitor lipase/esterase activity in real time, in which optimization and control strategies can be designed. PMID:25633600

[Analysis of saponins from panax notoginseng using pressurized solvent extraction coupled with liquid chromatography-electrospray mass spectrum].

PubMed

Wan, Jianbo; Li, Changming; Li, Shaopin; Kong, Lingyi; Wang, Yitao

2005-10-01

To establish a method for qualitative analysis of saponins from Panax notoginseng using pressurized solvent extraction coupled with LC-ESI-MS. The PSE technology was applied to the process of extraction for Panax notoginseng, and the negative ion detection and multiple reaction monitoring model were used. The saponins were investigated based on total ion chromatogram (TIC) and MRM chromatogram. According to the fragment character of saponins, the molecular weight and their structures could be identified. The method can be used for qualitative analysis of saponins from Panax notoginseng.

Rate coefficients for the reaction of formaldehyde with HO2 radicals from fluorescence spectroscopy of HOCH2OO radicals

NASA Astrophysics Data System (ADS)

Bunkan, Arne; Amédro, Damien; Crowley, John

2017-04-01

The reaction of formaldehyde with HO2 radicals constitutes a minor, but significant sink of formaldehyde in the troposphere as well as a possible interference in other formaldehyde photooxidation experiments. HCHO + HO2 ⇌ HOCH2OO (1) Due to the difficulty of simultaneously monitoring the reactant and product concentrations while preventing interfering secondary chemistry, there is a considerable uncertainty in the literature values for the reaction rate coefficients. We have used two photon, excited fragment spectroscopy (TPEFS), originally developed for monitoring HNO3 formation in kinetic experiments, to monitor the formation of the HOCH2OO radical. Dispersed and single wavelength fluorescence emission following the 193 nm photolysis of HOCH2OO have been recorded and analysed. Characterisation of the method is presented along with rate coefficients for the reaction of HCHO with HO2 radicals at tropospheric temperatures.

PTR-ToF-MS Coupled with an Automated Sampling System and Tailored Data Analysis for Food Studies: Bioprocess Monitoring, Screening and Nose-space Analysis.

PubMed

Capozzi, Vittorio; Yener, Sine; Khomenko, Iuliia; Farneti, Brian; Cappellin, Luca; Gasperi, Flavia; Scampicchio, Matteo; Biasioli, Franco

2017-05-11

Proton Transfer Reaction (PTR), combined with a Time-of-Flight (ToF) Mass Spectrometer (MS) is an analytical approach based on chemical ionization that belongs to the Direct-Injection Mass Spectrometric (DIMS) technologies. These techniques allow the rapid determination of volatile organic compounds (VOCs), assuring high sensitivity and accuracy. In general, PTR-MS requires neither sample preparation nor sample destruction, allowing real time and non-invasive analysis of samples. PTR-MS are exploited in many fields, from environmental and atmospheric chemistry to medical and biological sciences. More recently, we developed a methodology based on coupling PTR-ToF-MS with an automated sampler and tailored data analysis tools, to increase the degree of automation and, consequently, to enhance the potential of the technique. This approach allowed us to monitor bioprocesses (e.g. enzymatic oxidation, alcoholic fermentation), to screen large sample sets (e.g. different origins, entire germoplasms) and to analyze several experimental modes (e.g. different concentrations of a given ingredient, different intensities of a specific technological parameter) in terms of VOC content. Here, we report the experimental protocols exemplifying different possible applications of our methodology: i.e. the detection of VOCs released during lactic acid fermentation of yogurt (on-line bioprocess monitoring), the monitoring of VOCs associated with different apple cultivars (large-scale screening), and the in vivo study of retronasal VOC release during coffee drinking (nosespace analysis).

Quantitative Mass Spectrometry by Isotope Dilution and Multiple Reaction Monitoring (MRM).

PubMed

Russo, Paul; Hood, Brian L; Bateman, Nicholas W; Conrads, Thomas P

2017-01-01

Selected reaction monitoring (SRM) is used in molecular profiling to detect and quantify specific known proteins in complex mixtures. Using isotope dilution (Barnidge et al., Anal Chem 75(3):445-451, 2003) methodologies, peptides can be quantified without the need for an antibody-based method. Selected reaction monitoring assays employ electrospray ionization mass spectrometry (ESI-MS) followed by two stages of mass selection: a first stage where the mass of the peptide ion is selected and, after fragmentation by collision-induced dissociation (CID), a second stage (tandem MS) where either a single (e.g., SRM) or multiple (multiple reaction monitoring, MRM) specific peptide fragment ions are transmitted for detection. The MRM experiment is accomplished by specifying the parent masses of the selected endogenous and isotope-labeled peptides for MS/MS fragmentation and then monitoring fragment ions of interest, using their intensities/abundances and relative ratios to quantify the parent protein of interest. In this example protocol, we will utilize isotope dilution MRM-MS to quantify in absolute terms the total levels of the protein of interest, ataxia telangiectasia mutated (ATM) serine/threonine protein kinase. Ataxia telangiectasia mutated (ATM) phosphorylates several key proteins that initiate activation of the DNA damage checkpoint leading to cell cycle arrest.

Continuous monitoring of enzymatic activity within native electrophoresis gels: Application to mitochondrial oxidative phosphorylation complexes

PubMed Central

Covian, Raul; Chess, David; Balaban, Robert S.

2012-01-01

Native gel electrophoresis allows the separation of very small amounts of protein complexes while retaining aspects of their activity. In-gel enzymatic assays are usually performed by using reaction-dependent deposition of chromophores or light scattering precipitates quantified at fixed time points after gel removal and fixation, limiting the ability to analyze enzyme reaction kinetics. Herein, we describe a custom reaction chamber with reaction media recirculation and filtering and an imaging system that permits the continuous monitoring of in-gel enzymatic activity even in the presence of turbidity. Images were continuously collected using time-lapse high resolution digital imaging, and processing routines were developed to obtain kinetic traces of the in-gel activities and analyze reaction time courses. This system also permitted the evaluation of enzymatic activity topology within the protein bands of the gel. This approach was used to analyze the reaction kinetics of two mitochondrial complexes in native gels. Complex IV kinetics showed a short initial linear phase where catalytic rates could be calculated, whereas Complex V activity revealed a significant lag phase followed by two linear phases. The utility of monitoring the entire kinetic behavior of these reactions in native gels, as well as the general application of this approach, is discussed. PMID:22975200

Continuous monitoring of enzymatic activity within native electrophoresis gels: application to mitochondrial oxidative phosphorylation complexes.

PubMed

Covian, Raul; Chess, David; Balaban, Robert S

2012-12-01

Native gel electrophoresis allows the separation of very small amounts of protein complexes while retaining aspects of their activity. In-gel enzymatic assays are usually performed by using reaction-dependent deposition of chromophores or light-scattering precipitates quantified at fixed time points after gel removal and fixation, limiting the ability to analyze the enzyme reaction kinetics. Herein, we describe a custom reaction chamber with reaction medium recirculation and filtering and an imaging system that permits the continuous monitoring of in-gel enzymatic activity even in the presence of turbidity. Images were continuously collected using time-lapse high-resolution digital imaging, and processing routines were developed to obtain kinetic traces of the in-gel activities and analyze reaction time courses. This system also permitted the evaluation of enzymatic activity topology within the protein bands of the gel. This approach was used to analyze the reaction kinetics of two mitochondrial complexes in native gels. Complex IV kinetics showed a short initial linear phase in which catalytic rates could be calculated, whereas Complex V activity revealed a significant lag phase followed by two linear phases. The utility of monitoring the entire kinetic behavior of these reactions in native gels, as well as the general application of this approach, is discussed. Published by Elsevier Inc.

Label-free monitoring of interaction between DNA and oxaliplatin in aqueous solution by terahertz spectroscopy

NASA Astrophysics Data System (ADS)

Wu, Xiaojun; E, Yiwen; Xu, Xinlong; Wang, Li

2012-07-01

We demonstrated the feasibility of applying terahertz time-domain spectroscopy (THz-TDS) to monitor the molecular reactions in aqueous solutions of anticancer drug oxaliplatin with λ-DNA and macrophages DNA. The reaction time dependent refractive index and absorption coefficient were extracted and analyzed. The reaction half-decaying time of about 4.0 h for λ-DNA and 12.9 h for M-DNA was established. The results suggest that the THz-TDS detection could be an effective label-free technique to sense the molecular reaction in aqueous solutions and could be very useful in biology, medicine, and pharmacy industry.

Activation cross section and isomeric cross section ratio for the 76Ge(n,2n)75m,gGe process

NASA Astrophysics Data System (ADS)

Luo, Junhua; Jiang, Li; Wang, Xinxing

2018-04-01

We measured neutron-induced reaction cross sections for the 76Ge(n,2n)75m,gGe reactions and their isomeric cross section ratios σm/σg at three neutron energies between 13 and 15MeV by an activation and off-line γ-ray spectrometric technique using the K-400 Neutron Generator at the Chinese Academy of Engineering Physics (CAEP). Ge samples and Nb monitor foils were activated together to determine the reaction cross section and the incident neutron flux. The monoenergetic neutron beams were formed via the 3H( d, n)4He reaction. The pure cross section of the ground state was derived from the absolute cross section of the metastable state and the residual nuclear decay analysis. The cross sections were also calculated using the nuclear model code TALYS-1.8 with different level density options at neutron energies varying from the reaction threshold to 20MeV. Results are discussed and compared with the corresponding literature data.

Investigation of 3He-induced reactions on natural Ti for nuclear analytical and radionuclide production purposes

NASA Astrophysics Data System (ADS)

Ditrói, F.; Tárkányi, F.; Ali, M. A.; Andó, L.; Heselius, S.-J.; Shubin, Yu.; Youxiang, Zhuang; Mustafa, M. G.

2000-07-01

Excitation Russian Federation functions of 3He-induced nuclear reactions producing 43,44m,46,47,48Sc, 48V, 48,49,51Cr were measured up to 36 MeV bombarding energy by using the stacked-foil technique on different medium-energy accelerators. The results were compared with the data (cross-section, thick-target yield, activity-distribution functions, …) from the literature, model calculations and other measurements. Earlier measurements at higher energies up to 135 MeV are also plotted to complete the database for 3He-reactions on natural Ti. The new experimental and literature data were compared with the predictions of different model calculations for the 48V producing reactions. The selected experimental data sets were fitted using different methods to obtain recommended values. The measurements and compilation proved, that the 3He induced reactions on natural titanium, especially those leading to 48V and 48Cr are especially useful for monitoring, for activation analysis and for Thin Layer Activation (TLA) purposes. Production of 48V as a radiotracer is also recommended.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hirdt, J.A.; Brown, D.A., E-mail: dbrown@bnl.gov

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 socialmore » 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.« less

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

NASA Astrophysics Data System (ADS)

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.

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

PubMed

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.

A surface enhanced Raman scattering quantitative analytical platform for detection of trace Cu coupled the catalytic reaction and gold nanoparticle aggregation with label-free Victoria blue B molecular probe.

PubMed

Li, Chongning; Ouyang, Huixiang; Tang, Xueping; Wen, Guiqing; Liang, Aihui; Jiang, Zhiliang

2017-01-15

With development of economy and society, there is an urgent need to develop convenient and sensitive methods for detection of Cu 2+ pollution in water. In this article, a simple and sensitive SERS sensor was proposed to quantitative analysis of trace Cu 2+ in water. The SERS sensor platform was prepared a common gold nanoparticle (AuNP)-SiO 2 sol substrate platform by adsorbing HSA, coupling with the catalytic reaction of Cu 2+ -ascorbic acid (H 2 A)-dissolved oxygen, and using label-free Victoria blue B (VBB) as SERS molecular probes. The SERS sensor platform response to the AuNP aggregations by hydroxyl radicals (•OH) oxidizing from the Cu 2+ catalytic reaction, which caused the SERS signal enhancement. Therefore, by monitoring the increase of SERS signal, Cu 2+ in water can be determined accurately. The results show that the SERS sensor platforms owns a linear response with a range from 0.025 to 25μmol/L Cu 2+ , and with a detection limit of 0.008μmol/L. In addition, the SERS method demonstrated good specificity for Cu 2+ , which can determined accurately trace Cu 2+ in water samples, and good recovery and accuracy are obtained for the water samples. With its high selectivity and good accuracy, the sensitive SERS quantitative analysis method is expected to be a promising candidate for determining copper ions in environmental monitoring and food safety. Copyright © 2016 Elsevier B.V. All rights reserved.

Chemical characteristics and enhanced hepatoprotective activities of Maillard reaction products derived from milk protein-sugar system.

PubMed

Oh, Nam Su; Young Lee, Ji; Lee, Hyun Ah; Joung, Jae Yeon; Shin, Yong Kook; Kim, Sae Hun; Kim, Younghoon; Lee, Kwang Won

2016-02-01

The objective of this study was to investigate the characteristics, antioxidative properties, and hepatoprotective effects of Maillard reaction products (MRP) from milk protein reacted with sugars. The MRP were obtained from milk protein, whey protein concentrates and sodium caseinate, using 2 types of sugars, lactose and glucose, by heating the mixture at 55°C for 7d in a sodium phosphate buffer (pH 7.4). Changes in the chemical modification of the milk protein were monitored by measuring the protein-bound carbonyls and PAGE protein profiles. The results showed that the amount of protein-bound carbonyls increased after Maillard reaction (MR). In addition, sodium dodecyl sulfate-PAGE analysis indicated a formation of high-molecular weight complexes through MR. The modification sites induced by MR of milk protein were monitored by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis of tryptic-digested gel spots of MRP. As a result, modification and their localization in AA sequence of MRP was identified. Also, the MRP showed higher antioxidant activities than the intact milk protein, and they reduced intracellular reactive oxygen species production and inhibited the depletion of the reduced glutathione concentrations in the HepG2 cells. In particular, glucose-sodium caseinate MRP showed the highest biological activities among all MRP. Therefore, these results suggest that the MRP from milk protein reacting with sugars possess effective antioxidant activity and have a protective ability against oxidative damage. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

A novel headspace gas chromatographic method for in situ monitoring of monomer conversion during polymerization in an emulsion environment.

PubMed

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.

Novel 1H low field nuclear magnetic resonance applications for the field of biodiesel

PubMed Central

2013-01-01

Background Biodiesel production has increased dramatically over the last decade, raising the need for new rapid and non-destructive analytical tools and technologies. 1H Low Field Nuclear Magnetic Resonance (LF-NMR) applications, which offer great potential to the field of biodiesel, have been developed by the Phyto Lipid Biotechnology Lab research team in the last few years. Results Supervised and un-supervised chemometric tools are suggested for screening new alternative biodiesel feedstocks according to oil content and viscosity. The tools allowed assignment into viscosity groups of biodiesel-petrodiesel samples whose viscosity is unknown, and uncovered biodiesel samples that have residues of unreacted acylglycerol and/or methanol, and poorly separated and cleaned glycerol and water. In the case of composite materials, relaxation time distribution, and cross-correlation methods were successfully applied to differentiate components. Continuous distributed methods were also applied to calculate the yield of the transesterification reaction, and thus monitor the progress of the common and in-situ transesterification reactions, offering a tool for optimization of reaction parameters. Conclusions Comprehensive applied tools are detailed for the characterization of new alternative biodiesel resources in their whole conformation, monitoring of the biodiesel transesterification reaction, and quality evaluation of the final product, using a non-invasive and non-destructive technology that is new to the biodiesel research area. A new integrated computational-experimental approach for analysis of 1H LF-NMR relaxometry data is also presented, suggesting improved solution stability and peak resolution. PMID:23590829

Traceless Immobilization of Analytes for High-Throughput Experiments with SAMDI Mass Spectrometry.

PubMed

Helal, Kazi Y; Alamgir, Azmain; Berns, Eric J; Mrksich, Milan

2018-06-21

Label-free assays, and particularly those based on the combination of mass spectroscopy with surface chemistries, enable high-throughput experiments of a broad range of reactions. However, these methods can still require the incorporation of functional groups that allow immobilization of reactants and products to surfaces prior to analysis. In this paper, we report a traceless method for attaching molecules to a self-assembled monolayer for matrix-assisted laser desorption and ionization (SAMDI) mass spectrometry. This method uses monolayers that are functionalized with a 3-trifluoromethyl-3-phenyl-diazirine group that liberates nitrogen when irradiated and gives a carbene that inserts into a wide range of bonds to covalently immobilize molecules. Analysis of the monolayer with SAMDI then reveals peaks for each of the adducts formed from molecules in the sample. This method is applied to characterize a P450 drug metabolizing enzyme and to monitor a Suzuki-Miyaura coupling chemical reaction and is important because modification of the substrates with a functional group would alter their activities. This method will be important for high-throughput experiments in many areas, including reaction discovery and optimization.

Characterization of the crosslinking reaction in high performance phenolic resins

NASA Astrophysics Data System (ADS)

Patel, Jigneshkumar; Zou, Guo Xiang; Hsu, Shaw Ling; university of massachusetts/Polymer science; Engineering Team

In this study, a combination of thermal analysis, infrared spectroscopy (near and mid) in conjunction with low field NMR, was used to characterize the crosslinking reaction involving phenol formaldehyde resin and a crosslinking agent, Hexamethylenetetramine (HMTA). The strong hydrogen bonds in the resin and the completely crystalline HMTA (Tm = 280 °C) severely hamper the crosslinking process. Yet the addition of a small amount of plasticizer can induce a highly efficient crosslinking reaction to achieve the desired mechanical properties needed in a number of high performance organic-inorganic composites. The infrared spectroscopy clarifies the dissolution process of the crystalline crosslinker and the specific interactions needed to achieve miscibility of the reactants. The thermal analysis enabled us to follow the changing mobility of the system as a function of temperature. The low field NMR with the T1 inverse recovery technique allowed us to monitor the crosslinking process directly. For the first time, it is now possible to identify the functionality of the plasticizer and correlate the crosslinked structure achieved to the macroscopic performance needed for high performance organic-inorganic composites.

Identification and determination of fat-soluble vitamins and metabolites in human serum by liquid chromatography/triple quadrupole mass spectrometry with multiple reaction monitoring.

PubMed

Priego Capote, Feliciano; Jiménez, José Ruiz; Granados, José María Mata; de Castro, María Dolores Luque

2007-01-01

A method for determination of fat-soluble vitamins K(1), K(3), A, D(2), D(3) and E (as alpha- and delta-tocopherol) and metabolites 25-hydroxyvitamin D(2) and D(3) and 1,25-dihydroxyvitamin D(3) in human serum by liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) in positive mode is proposed. Highly selective identification of the target compounds in serum was confirmed by the most representative transitions from precursor ion to product ion. Quantitative MS/MS analysis was carried out by multiple reaction monitoring optimizing the most sensitive transition for each analyte in order to achieve low detection limits (from 0.012 to 0.3 ng/mL estimated with serum). The analysis was performed with 1 mL of serum, which was subjected to protein precipitation, liquid-liquid extraction to an organic phase, evaporation to dryness and reconstitution with methanol. The precision of the overall method ranged from 3.17-6.76% as intra-day variability and from 5.07-11.53% as inter-day variability. The method, validated by the standard addition method, provides complete information on the fat-soluble vitamins profile, which is of interest in clinical and metabolomics studies.

Proteomic analysis of serum biomarkers for prediabetes using the Long-Evans Agouti rat, a spontaneous animal model of type 2 diabetes mellitus.

PubMed

Takahashi, Eri; Unoki-Kubota, Hiroyuki; Shimizu, Yukiko; Okamura, Tadashi; Iwata, Wakiko; Kajio, Hiroshi; Yamamoto-Honda, Ritsuko; Shiga, Tomoko; Yamashita, Shigeo; Tobe, Kazuyuki; Okumura, Akinori; Matsumoto, Michihiro; Yasuda, Kazuki; Noda, Mitsuhiko; Kaburagi, Yasushi

2017-09-01

To identify candidate serum molecules associated with the progression of type 2 diabetes mellitus, differential serum proteomic analysis was carried out on a spontaneous animal model of type 2 diabetes mellitus without obesity, the Long-Evans Agouti (LEA) rat. We carried out quantitative proteomic analysis using serum samples from 8- and 16-week-old LEA and control Brown Norway (BN) rats (n = 4/group). Differentially expressed proteins were validated by multiple reaction monitoring analysis using the sera collected from 8-, 16-, and 24-week-old LEA (n = 4/each group) and BN rats (n = 5/each group). Among the validated proteins, we also examined the possible relevance of the human homolog of serine protease inhibitor A3 (SERPINA3) to type 2 diabetes mellitus. The use of 2-D fluorescence difference gel electrophoresis analysis and the following liquid chromatography-multiple reaction monitoring analysis showed that the serum levels of five proteins were differentially changed between LEA rats and BN rats at all three time-points examined. Among the five proteins, SERPINA3N was increased significantly in the sera of LEA rats compared with age-matched BN rats. The serum level of SERPINA3 was also found to be significantly higher in type 2 diabetes mellitus patients than in healthy control participants. Furthermore, glycated hemoglobin, fasting insulin and estimated glomerular filtration rate were independently associated with the SERPINA3 levels. These findings suggest a possible role for SERPINA3 in the development of the early stages of type 2 diabetes mellitus, although further replication studies and functional investigations regarding their role are required. © 2017 The Authors. Journal of Diabetes Investigation published by Asian Association for the Study of Diabetes (AASD) and John Wiley & Sons Australia, Ltd.

Interplay between Reaction and Phase Behaviour in Carbon Dioxide Hydrogenation to Methanol.

PubMed

Reymond, Helena; Amado-Blanco, Victor; Lauper, Andreas; Rudolf von Rohr, Philipp

2017-03-22

Condensation promotes CO 2 hydrogenation to CH 3 OH beyond equilibrium through in situ product separation. Although primordial for catalyst and reactor design, triggering conditions as well as the impact on sub-equilibrium reaction behaviour remain unclear. Herein we used an in-house designed micro-view-cell to gain chemical and physical insights into reaction and phase behaviour under high-pressure conditions over a commercial Cu/ZnO/Al 2 O 3 catalyst. Raman microscopy and video monitoring, combined with online gas chromatography analysis, allowed the complete characterisation of the reaction bulk up to 450 bar (1 bar=0.1 MPa) and 350 °C. Dew points of typical effluent streams related to a parametric study suggest that the improving reaction performance and reverting selectivities observed from 230 °C strongly correlate with (i) a regime transition from kinetic to thermodynamic, and (ii) a phase transition from a single supercritical to a biphasic reaction mixture. Our results advance a rationale behind transitioning CH 3 OH selectivities for an improved understanding of CO 2 hydrogenation under high pressure. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guan, Jiwen; Song, Yang, E-mail: yang.song@uwo.ca; Department of Chemistry, University of Western Ontario, London, Ontario N6A 5B7

The polymerization process of condensed styrene to produce polystyrene as an industrially important polymeric material was investigated using a novel approach by combining external compression with ultraviolet radiation. The reaction evolution was monitored as a function of time and the reaction products were characterized by in situ Fourier transform infrared spectroscopy. By optimizing the loading pressures, we observed highly efficient and selective production of polystyrene of different tacticities. Specifically, at relatively low loading pressures, infrared spectra suggest that styrene monomers transform to amorphous atactic polystyrene (APS) with minor crystalline isotactic polystyrene. In contrast, APS was found to be the solemore » product when polymerization occurs at relatively higher loading pressures. The time-dependent reaction profiles allow the examination of the polymerization kinetics by analyzing the rate constant and activation volume as a function of pressure. As a result, an optimized pressure condition, which allows a barrierless reaction to proceed, was identified and attributed to the very desirable reaction yield and kinetics. Finally, the photoinitiated reaction mechanism and the growth geometry of the polymer chains were investigated from the energy diagram of styrene and by the topology analysis of the crystal styrene. This study shows strong promise to produce functional polymeric materials in a highly efficient and controlled manner.« less

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

PubMed

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.

Desktop NMR spectroscopy for real-time monitoring of an acetalization reaction in comparison with gas chromatography and NMR at 9.4 T.

PubMed

Singh, Kawarpal; Danieli, Ernesto; Blümich, Bernhard

2017-12-01

Monitoring of chemical reactions in real-time is in demand for process control. Different methods such as gas chromatography (GC), mass spectroscopy, infrared spectroscopy, and nuclear magnetic resonance (NMR) are used for that purpose. The current state-of-the-art compact NMR systems provide a useful method to employ with various reaction conditions for studying chemical reactions inside the fume hood at the chemical workplace. In the present study, an acetalization reaction was investigated with compact NMR spectroscopy in real-time. Acetalization is used for multistep synthesis of the variety of organic compounds to protect particular chemical groups. A compact 1 T NMR spectrometer with a permanent magnet was employed to monitor the acid catalyzed acetalization of the p-nitrobenzaldehyde with ethylene glycol. The concentrations of both reactant and product were followed by peak integrals in single-scan 1 H NMR spectra as a function of time. The reaction conditions were varied in terms of temperature, agitation speed, catalyst loading, and feed concentrations in order to determine the activation energy with the help of a pseudo-homogeneous kinetic model. For low molar ratios of aldehyde and glycol, the equilibrium conversions were lower than for the stoichiometric ratio. Increasing catalyst concentration leads to faster conversion. The data obtained with low-field NMR spectroscopy were compared with data from GC and NMR spectroscopy at 9.4 T acquired in batch mode by extracting samples at regular time intervals. The reaction kinetics followed by either method agreed well. The activation energies for forward and backward reactions were determined by real-time monitoring with compact NMR at 1 T were 48 ± 5 and 60 ± 4 kJ/mol, respectively. The activation energies obtained with gas chromatography for forward and backward reactions were 48 ± 4 and 51 ± 4 kJ/mol. The equilibrium constant decreases with increasing temperature as expected for an exothermic reaction. The impact of dense sampling with online NMR and sparse sampling with GC was observed on the kinetic outcome using the same kinetic model. Graphical abstract Acetalization reaction kinetics were monitored with real-time desktop NMR spectroscopy at 1 T. Each data point was obtained at regular intervals with a single shot in 15 s. The kinetics was compared with sparsely sampled data obtained with GC and NMR at 9.4 T.

Kinetics and inhibition of cyclomaltodextrinase from alkalophilic Bacillus sp. I-5.

PubMed

Kim, M J; Park, W S; Lee, H S; Kim, T J; Shin, J H; Yoo, S H; Cheong, T K; Ryu, S; Kim, J C; Kim, J W; Moon, T W; Robyt, J F; Park, K H

2000-01-01

The cyclomaltodextrinase from alkalophilic Bacillus sp. I-5 (CDase I-5) was expressed in Escherichia coli and the purified enzyme was used for characterization of the enzyme action. The hydrolysis products were monitored by both HPLC and high-performance ion chromatography analysis that enable the kinetic analysis of the cyclomaltodextrin (CD)-degrading reaction. Analysis of the kinetics of cyclomaltodextrin hydrolysis by CDase I-5 indicated that ring-opening of the cyclomaltodextrin was the major limiting step and that CDase I-5 preferentially degraded the linear maltodextrin chain by removing the maltose unit. The substrate binding affinity of the enzyme was almost same for those of cyclomaltodextrins while the rate of ring-opening was the fastest for cyclomaltoheptaose. Acarbose and methyl 6-amino-6-deoxy-alpha-d-glucopyranoside were relatively strong competitive inhibitors with K(i) values of 1.24 x 10(-3) and 8.44 x 10(-1) mM, respectively. Both inhibitors are likely to inhibit the ring-opening step of the CD degradation reaction. Copyright 2000 Academic Press.

New strategy to identify radicals in a time evolving EPR data set by multivariate curve resolution-alternating least squares.

PubMed

Fadel, Maya Abou; de Juan, Anna; Vezin, Hervé; Duponchel, Ludovic

2016-12-01

Electron paramagnetic resonance (EPR) spectroscopy is a powerful technique that is able to characterize radicals formed in kinetic reactions. However, spectral characterization of individual chemical species is often limited or even unmanageable due to the severe kinetic and spectral overlap among species in kinetic processes. Therefore, we applied, for the first time, multivariate curve resolution-alternating least squares (MCR-ALS) method to EPR time evolving data sets to model and characterize the different constituents in a kinetic reaction. Here we demonstrate the advantage of multivariate analysis in the investigation of radicals formed along the kinetic process of hydroxycoumarin in alkaline medium. Multiset analysis of several EPR-monitored kinetic experiments performed in different conditions revealed the individual paramagnetic centres as well as their kinetic profiles. The results obtained by MCR-ALS method demonstrate its prominent potential in analysis of EPR time evolved spectra. Copyright © 2016 Elsevier B.V. All rights reserved.

Label-free thioflavin T/G-quadruplex-based real-time strand displacement amplification for biosensing applications.

PubMed

Du, Yi-Chen; Zhu, Li-Na; Kong, De-Ming

2016-12-15

To promote application of strand-displacement amplification (SDA) techniques in biosensing, a label-free, real-time monitoring strategy for isothermal nucleic acid amplification reactions was designed. G-quadruplex structures were introduced into SDA products using specific recognition of G-quadruplexes by the fluorogenic dye thioflavin T. Performance was good for real-time monitoring of traditional SDA by a linear-amplification mechanism and for exponential cross-triggered SDA amplification. The strategy worked on a commercial real-time PCR instrument, making it suitable for biosensing platforms. As examples, two highly sensitive and specific biosensors were designed for analysis of the activity of uracil-DNA glycosylase (UDG) and the restriction endonuclease EcoRI. Detection limits were 6×10(-5)U/mL for UDG and 0.016U/mL for EcoRI. Detection of corresponding targets in complex matrices such as cell lysates or human serum was also demonstrated. Compared to traditional end-point detection methods, real-time SDA-based approaches have the advantages of simple, fast operation; high sensitivity; low risk of carryover contamination; and very high throughput. The introduction of real-time monitoring strategies may promote application of SDA reactions in biosensor design. Copyright © 2016 Elsevier B.V. All rights reserved.

Comparison of Quantitative Mass Spectrometry Platforms for Monitoring Kinase ATP Probe Uptake in Lung Cancer.

PubMed

Hoffman, Melissa A; Fang, Bin; Haura, Eric B; Rix, Uwe; Koomen, John M

2018-01-05

Recent developments in instrumentation and bioinformatics have led to new quantitative mass spectrometry platforms including LC-MS/MS with data-independent acquisition (DIA) and targeted analysis using parallel reaction monitoring mass spectrometry (LC-PRM), which provide alternatives to well-established methods, such as LC-MS/MS with data-dependent acquisition (DDA) and targeted analysis using multiple reaction monitoring mass spectrometry (LC-MRM). These tools have been used to identify signaling perturbations in lung cancers and other malignancies, supporting the development of effective kinase inhibitors and, more recently, providing insights into therapeutic resistance mechanisms and drug repurposing opportunities. However, detection of kinases in biological matrices can be challenging; therefore, activity-based protein profiling enrichment of ATP-utilizing proteins was selected as a test case for exploring the limits of detection of low-abundance analytes in complex biological samples. To examine the impact of different MS acquisition platforms, quantification of kinase ATP uptake following kinase inhibitor treatment was analyzed by four different methods: LC-MS/MS with DDA and DIA, LC-MRM, and LC-PRM. For discovery data sets, DIA increased the number of identified kinases by 21% and reduced missingness when compared with DDA. In this context, MRM and PRM were most effective at identifying global kinome responses to inhibitor treatment, highlighting the value of a priori target identification and manual evaluation of quantitative proteomics data sets. We compare results for a selected set of desthiobiotinylated peptides from PRM, MRM, and DIA and identify considerations for selecting a quantification method and postprocessing steps that should be used for each data acquisition strategy.

Optofluidic UV-Vis spectrophotometer for online monitoring of photocatalytic reactions

NASA Astrophysics Data System (ADS)

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.

Rapid identification of antibiotic resistance using droplet microfluidics.

PubMed

Keays, Marie C; O'Brien, Mark; Hussain, Anam; Kiely, Patrick A; Dalton, Tara

2016-04-02

Culturing bacteria and monitoring bacterial cell growth is a critical issue when dealing with patients who present with bacterial infections. One of the main challenges that arises is the time taken to identify the particular strain of bacteria and consequently, decide the correct treatment. In the majority of cases, broad spectrum antibiotics are used to target infections when a narrow spectrum drug would be more appropriate. The efficient monitoring of bacterial growth and potential antibiotic resistance is necessary to identify the best treatment options for patients. Minturising the reactions into microfluidic droplets offers a novel method to rapidy analyze bacteria. Microfluidics facilitates low volume reactions that provide a unique system where each droplet reaction acts as an individual bioreactor. Here, we designed and built a novel platform that allowed us to create and monitor E.coli microfluidic droplet cultures. Optical capacity was built in and measurements of bacterial cultures were captured facilitating the continuous monitoring of individual reactions. The capacity of the instrument was demonstrated by the application of treatments to both bacteria and drug resistant strains of bacteria. We were able to detect responses within one hour in the droplet cultures, demonstrating the capacity of this workflow to the culture and rapid characterization of bacterial strains.

Optofluidic UV-Vis spectrophotometer for online monitoring of photocatalytic reactions

PubMed Central

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

2016-01-01

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. PMID:27352840

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

PubMed

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.

Excitation functions of nuclear reactions induced by alpha particles up to 42 MeV on natTi for monitoring purposes and TLA

NASA Astrophysics Data System (ADS)

Hermanne, A.; Sonck, M.; Takács, S.; Szelecsényi, F.; Tárkányi, F.

1999-05-01

Excitation functions for the reactions induced by alpha particles on natTi foils and leading to the formation of 44m,44g,46,47,48Sc; 48,51Cr and 48V were determined using the stacked foil technique for energies from the respective reaction thresholds up to 42 MeV. The new experimental values are compared to earlier literature values and generally good accordance is found. It appears that the natTi(α,x) 51Cr reaction is particularly useful for monitoring α-beams in the 10-20 MeV region while for energies above 20 MeV the natTi(α,x) 47Sc reaction or the natTi(α,x) 48V reaction are more suited. The excitation functions established can be used to determine calibration curves for thin layer activation (TLA) as well.

Spectrophotometric analyses of hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) in water.

PubMed

Shi, Cong; Xu, Zhonghou; Smolinski, Benjamin L; Arienti, Per M; O'Connor, Gregory; Meng, Xiaoguang

2015-07-01

A simple and accurate spectrophotometric method for on-site analysis of royal demolition explosive (RDX) in water samples was developed based on the Berthelot reaction. The sensitivity and accuracy of an existing spectrophotometric method was improved by: replacing toxic chemicals with more stable and safer reagents; optimizing the reagent dose and reaction time; improving color stability; and eliminating the interference from inorganic nitrogen compounds in water samples. Cation and anion exchange resin cartridges were developed and used for sample pretreatment to eliminate the effect of ammonia and nitrate on RDX analyses. The detection limit of the method was determined to be 100 μg/L. The method was used successfully for analysis of RDX in untreated industrial wastewater samples. It can be used for on-site monitoring of RDX in wastewater for early detection of chemical spills and failure of wastewater treatment systems. Copyright © 2015. Published by Elsevier B.V.

Simple quantification of surface carboxylic acids on chemically oxidized multi-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Gong, Hyejin; Kim, Seong-Taek; Lee, Jong Doo; Yim, Sanggyu

2013-02-01

The surface of multi-walled carbon nanotube (MWCNT) was chemically oxidized using nitric acid and sulfuric-nitric acid mixtures. Thermogravimetric analysis, transmission electron microscopy and infrared spectroscopy revealed that the use of acid mixtures led to higher degree of oxidation. More quantitative identification of surface carboxylic acids was carried out using X-ray photoelectron spectroscopy (XPS) and acid-base titration. However, these techniques are costly and require very long analysis times to promptly respond to the extent of the reaction. We propose a much simpler method using pH measurements and pre-determined pKa value in order to estimate the concentration of carboxylic acids on the oxidized MWCNT surfaces. The results from this technique were consistent with those obtained from XPS and titration, and it is expected that this simple quantification method can provide a cheap and fast way to monitor and control the oxidation reaction of MWCNT.

Spectrophotometric determination of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride by flow injection analysis.

PubMed

Seno, Kunihiko; Matumura, Kazuki; Oshima, Mitsuko; Motomizu, Shoji

2008-04-01

1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (EDC.HCl) is a very useful agent to form amide bonds (peptide bonds) in an aqueous medium. A simple and fast detection system was developed using the reaction with pyridine and ethylenediamine in acidic aqueous solution and spectrophotometric flow injection analysis. The absorbances were measured at 400 nm and the reaction was accelerated at 40 degrees C. The calibration graph showed good linearity from 0 to 10% of EDC.HCl solutions: the regression equation was y=3.15x10(4)x (y, peak area; x, % concentration of EDC.HCl). The RSD was under 1.0%. Sample throughput was 15 h(-1). This method was applied to monitoring the EDC.HCl concentration that remained after the anhydration of phthalic acid in water, esterification of acetic acid in methanol or dehydration condensation of malonic acid and ethylenediamine in water.

A DFT-Based Computational-Experimental Methodology for Synthetic Chemistry: Example of Application to the Catalytic Opening of Epoxides by Titanocene.

PubMed

Jaraíz, Martín; Enríquez, Lourdes; Pinacho, Ruth; Rubio, José E; Lesarri, Alberto; López-Pérez, José L

2017-04-07

A novel DFT-based Reaction Kinetics (DFT-RK) simulation approach, employed in combination with real-time data from reaction monitoring instrumentation (like UV-vis, FTIR, Raman, and 2D NMR benchtop spectrometers), is shown to provide a detailed methodology for the analysis and design of complex synthetic chemistry schemes. As an example, it is applied to the opening of epoxides by titanocene in THF, a catalytic system with abundant experimental data available. Through a DFT-RK analysis of real-time IR data, we have developed a comprehensive mechanistic model that opens new perspectives to understand previous experiments. Although derived specifically from the opening of epoxides, the prediction capabilities of the model, built on elementary reactions, together with its practical side (reaction kinetics simulations of real experimental conditions) make it a useful simulation tool for the design of new experiments, as well as for the conception and development of improved versions of the reagents. From the perspective of the methodology employed, because both the computational (DFT-RK) and the experimental (spectroscopic data) components can follow the time evolution of several species simultaneously, it is expected to provide a helpful tool for the study of complex systems in synthetic chemistry.

Estimation of ground reaction forces and joint moments on the basis on plantar pressure insoles and wearable sensors for joint angle measurement.

PubMed

Ostaszewski, Michal; Pauk, Jolanta

2018-05-16

Gait analysis is a useful tool medical staff use to support clinical decision making. There is still an urgent need to develop low-cost and unobtrusive mobile health monitoring systems. The goal of this study was twofold. Firstly, a wearable sensor system composed of plantar pressure insoles and wearable sensors for joint angle measurement was developed. Secondly, the accuracy of the system in the measurement of ground reaction forces and joint moments was examined. The measurements included joint angles and plantar pressure distribution. To validate the wearable sensor system and examine the effectiveness of the proposed method for gait analysis, an experimental study on ten volunteer subjects was conducted. The accuracy of measurement of ground reaction forces and joint moments was validated against the results obtained from a reference motion capture system. Ground reaction forces and joint moments measured by the wearable sensor system showed a root mean square error of 1% for min. GRF and 27.3% for knee extension moment. The correlation coefficient was over 0.9, in comparison with the stationary motion capture system. The study suggests that the wearable sensor system could be recommended both for research and clinical applications outside a typical gait laboratory.

Postmarket Drug Surveillance Without Trial Costs: Discovery of Adverse Drug Reactions Through Large-Scale Analysis of Web Search Queries

PubMed Central

Gabrilovich, Evgeniy

2013-01-01

Background Postmarket drug safety surveillance largely depends on spontaneous reports by patients and health care providers; hence, less common adverse drug reactions—especially those caused by long-term exposure, multidrug treatments, or those specific to special populations—often elude discovery. Objective Here we propose a low cost, fully automated method for continuous monitoring of adverse drug reactions in single drugs and in combinations thereof, and demonstrate the discovery of heretofore-unknown ones. Methods We used aggregated search data of large populations of Internet users to extract information related to drugs and adverse reactions to them, and correlated these data over time. We further extended our method to identify adverse reactions to combinations of drugs. Results We validated our method by showing high correlations of our findings with known adverse drug reactions (ADRs). However, although acute early-onset drug reactions are more likely to be reported to regulatory agencies, we show that less acute later-onset ones are better captured in Web search queries. Conclusions Our method is advantageous in identifying previously unknown adverse drug reactions. These ADRs should be considered as candidates for further scrutiny by medical regulatory authorities, for example, through phase 4 trials. PMID:23778053

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

PubMed

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.

Practical approaches to the ESI-MS analysis of catalytic reactions.

PubMed

Yunker, Lars P E; Stoddard, Rhonda L; McIndoe, J Scott

2014-01-01

Electrospray ionization mass spectrometry (ESI-MS) is a soft ionization technique commonly coupled with liquid or gas chromatography for the identification of compounds in a one-time view of a mixture (for example, the resulting mixture generated by a synthesis). Over the past decade, Scott McIndoe and his research group at the University of Victoria have developed various methodologies to enhance the ability of ESI-MS to continuously monitor catalytic reactions as they proceed. The power, sensitivity and large dynamic range of ESI-MS have allowed for the refinement of several homogenous catalytic mechanisms and could potentially be applied to a wide range of reactions (catalytic or otherwise) for the determination of their mechanistic pathways. In this special feature article, some of the key challenges encountered and the adaptations employed to counter them are briefly reviewed. Copyright © 2014 John Wiley & Sons, Ltd.

Four reversible and reconfigurable structures for three-phase emulsions: extended morphologies and applications

NASA Astrophysics Data System (ADS)

Ge, Xue-Hui; Geng, Yu-Hao; Zhang, Qiao-Chu; Shao, Meng; Chen, Jian; Luo, Guang-Sheng; Xu, Jian-Hong

2017-02-01

Here in this article, we classify and conclude the four morphologies of three-phase emulsions. Remarkably, we achieve the reversible transformations between every shape. Through theoretical analysis, we choose four liquid systems to form these four morphologies. Then monodispersed droplets with these four morphologies are formed through a microfluidic device and captured in a petri-dish. By replacing their ambient solution of the captured emulsions, in-situ morphology transformations between each shape are achieved. The process is well recorded through photographs and videos and they are systematical and reversible. Finally, we use the droplets structure to form an on-off switch to start and shut off the evaporation of one volatile phase to achieve the process monitoring. This could be used to initiate and quench a reaction, which offers a novel idea to achieve the switchable and reversible reaction control in multiple-phase reactions.

Nexavar®-related adverse reactions: Calabrian (Italy) experience for sorafenib exposition in 2012

PubMed Central

Cilurzo, Felisa; Staltari, Orietta; Patanè, Marinella; Ammendola, Michele; Garaffo, Caterina; Di Paola, Eugenio Donato

2013-01-01

Hepatocellular carcinoma (HCC) remains a major global health problem and Calabria in the south of Italy is not an exception. Sorafenib is the first and only Food and Drug Administration approved drug for the treatment of advanced HCC and it is currently under intensive monitoring by the Health Authorities in Italy Agenzia Italiana del Farmaco. This general report has been developed with the aim of briefly reviewing the data found in the reports of adverse reactions (ADRs) collected in Calabria in 2012 for sorafenib treated patients. Extrapolated data have highlighted some differences between the adverse drug reactions reported in patients younger or older than 70 years and other important differences with the current approved leaflet. Several limitations might be present in data analysis form spontaneous reporting, however, the relevance of reporting ADRs (dermatitis, asthenia, vomiting, etc.) for the early identification of drug related signals has to be underlined. PMID:24347990

Sensitive and specific identification by polymerase chain reaction of Eimeria tenella and Eimeria maxima, important protozoan pathogens in laboratory avian facilities.

PubMed

Lee, Hyun-A; Hong, Sunhwa; Chung, Yungho; Kim, Okjin

2011-09-01

Eimeria tenella and Eimeria maxima are important pathogens causing intracellular protozoa infections in laboratory avian animals and are known to affect experimental results obtained from contaminated animals. This study aimed to find a fast, sensitive, and efficient protocol for the molecular identification of E. tenella and E. maxima in experimental samples using chickens as laboratory avian animals. DNA was extracted from fecal samples collected from chickens and polymerase chain reaction (PCR) analysis was employed to detect E. tenella and E. maxima from the extracted DNA. The target nucleic acid fragments were specifically amplified by PCR. Feces secreting E. tenella and E. maxima were detected by a positive PCR reaction. In this study, we were able to successfully detect E. tenella and E. maxima using the molecular diagnostic method of PCR. As such, we recommended PCR for monitoring E. tenella and E. maxima in laboratory avian facilities.

Automated selected reaction monitoring data analysis workflow for large-scale targeted proteomic studies.

PubMed

Surinova, Silvia; Hüttenhain, Ruth; Chang, Ching-Yun; Espona, Lucia; Vitek, Olga; Aebersold, Ruedi

2013-08-01

Targeted proteomics based on selected reaction monitoring (SRM) mass spectrometry is commonly used for accurate and reproducible quantification of protein analytes in complex biological mixtures. Strictly hypothesis-driven, SRM assays quantify each targeted protein by collecting measurements on its peptide fragment ions, called transitions. To achieve sensitive and accurate quantitative results, experimental design and data analysis must consistently account for the variability of the quantified transitions. This consistency is especially important in large experiments, which increasingly require profiling up to hundreds of proteins over hundreds of samples. Here we describe a robust and automated workflow for the analysis of large quantitative SRM data sets that integrates data processing, statistical protein identification and quantification, and dissemination of the results. The integrated workflow combines three software tools: mProphet for peptide identification via probabilistic scoring; SRMstats for protein significance analysis with linear mixed-effect models; and PASSEL, a public repository for storage, retrieval and query of SRM data. The input requirements for the protocol are files with SRM traces in mzXML format, and a file with a list of transitions in a text tab-separated format. The protocol is especially suited for data with heavy isotope-labeled peptide internal standards. We demonstrate the protocol on a clinical data set in which the abundances of 35 biomarker candidates were profiled in 83 blood plasma samples of subjects with ovarian cancer or benign ovarian tumors. The time frame to realize the protocol is 1-2 weeks, depending on the number of replicates used in the experiment.

Floating Droplet Array: An Ultrahigh-Throughput Device for Droplet Trapping, Real-time Analysis and Recovery

PubMed Central

Labanieh, Louai; Nguyen, Thi N.; Zhao, Weian; Kang, Dong-Ku

2016-01-01

We describe the design, fabrication and use of a dual-layered microfluidic device for ultrahigh-throughput droplet trapping, analysis, and recovery using droplet buoyancy. To demonstrate the utility of this device for digital quantification of analytes, we quantify the number of droplets, which contain a β-galactosidase-conjugated bead among more than 100,000 immobilized droplets. In addition, we demonstrate that this device can be used for droplet clustering and real-time analysis by clustering several droplets together into microwells and monitoring diffusion of fluorescein, a product of the enzymatic reaction of β-galactosidase and its fluorogenic substrate FDG, between droplets. PMID:27134760

Applications of breath gas analysis in medicine

NASA Astrophysics Data System (ADS)

Amann, Anton; Poupart, Guy; Telser, Stefan; Ledochowski, Maximilian; Schmid, Alex; Mechtcheriakov, Sergei

2004-12-01

Volatile organic compounds (VOCs) in exhaled breath gas provide valuable information about the subjects' physiological and pathophysiological condition. Proton-transfer-reaction mass spectrometry (PTR-MS) allows rapid and online measurements of these substances. We present results of three studies illustrating the potential of breath gas analysis by PTR-MS in various contexts: long-time online monitoring of VOCs in sleeping subjects suggests that VOC profiles are related to sleep stages. Analysis of VOC concentrations in the breath of carbohydrate malabsorbers emphasizes the role played by bacteria in the gut. Finally, we demonstrate the large intra- and intersubject concentration variability of VOCs by considering one particular mass.

Comparison between qualitative and real-time polymerase chain reaction to evaluate minimal residual disease in children with acute lymphoblastic leukemia.

PubMed

Paula, Francisco Danilo Ferreira; Elói-Santos, Silvana Maria; Xavier, Sandra Guerra; Ganazza, Mônica Aparecida; Jotta, Patricia Yoshioka; Yunes, José Andrés; Viana, Marcos Borato; Assumpção, Juliana Godoy

2015-01-01

Minimal residual disease is an important independent prognostic factor that can identify poor responders among patients with acute lymphoblastic leukemia. The aim of this study was to analyze minimal residual disease using immunoglobulin (Ig) and T-cell receptor (TCR) gene rearrangements by conventional polymerase chain reaction followed by homo-heteroduplex analysis and to compare this with real-time polymerase chain reaction at the end of the induction period in children with acute lymphoblastic leukemia. Seventy-four patients diagnosed with acute lymphoblastic leukemia were enrolled. Minimal residual disease was evaluated by qualitative polymerase chain reaction in 57 and by both tests in 44. The Kaplan-Meier and multivariate Cox methods and the log-rank test were used for statistical analysis. Nine patients (15.8%) were positive for minimal residual disease by qualitative polymerase chain reaction and 11 (25%) by real-time polymerase chain reaction considering a cut-off point of 1×10(-3) for precursor B-cell acute lymphoblastic leukemia and 1×10(-2) for T-cell acute lymphoblastic leukemia. Using the qualitative method, the 3.5-year leukemia-free survival was significantly higher in children negative for minimal residual disease compared to those with positive results (84.1%±5.6% versus 41.7%±17.3%, respectively; p-value=0.004). There was no significant association between leukemia-free survival and minimal residual disease by real-time polymerase chain reaction. Minimal residual disease by qualitative polymerase chain reaction was the only variable significantly correlated to leukemia-free survival. Given the difficulties in the implementation of minimal residual disease monitoring by real-time polymerase chain reaction in most treatment centers in Brazil, the qualitative polymerase chain reaction strategy may be a cost-effective alternative. Copyright © 2015 Associação Brasileira de Hematologia, Hemoterapia e Terapia Celular. Published by Elsevier Editora Ltda. All rights reserved.

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

DOE Office of Scientific and Technical Information (OSTI.GOV)

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 ofmore » 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.« less

NCI Launches Proteomics Assay Portal | Office of Cancer Clinical Proteomics Research

Cancer.gov

In a paper recently published by the journal Nature Methods, Investigators from the National Cancer Institute’s Clinical Proteomic Tumor Analysis Consortium (NCI-CPTAC) announced the launch of a proteomics Assay Portal for multiple reaction monitoring-mass spectrometry (MRM-MS) assays.  This community web-based repository for well-characterized quantitative proteomic assays currently consists of 456 unique peptide assays to 282 unique proteins and ser

Synthesis of Energetic Polymers.

DTIC Science & Technology

1981-10-15

demonstrated by a single peak in the gc analysis (injector temperature 2500 C). The reaction will be repeated in a different solvent to avoid the formation of...glass column packed with 10% OV-101 on chrom Q, with n-decane as an internal standard. Rates of polymerization were calculated using the assumption...the Kelen-Tudos method. The disappearance of monomer was monitored by gas chromatography, using a glass column packed with 10% OV-101 on Chrom Q

Pseudohallucinations associated with moclobemide: a case report.

PubMed

Degner, D; Kropp, S; Porzig, J; Grohmann, R; Rüther, E

2005-07-01

The goal of the multicenter drug surveillance project AMSP ("Arzneimittelsicherheit in der Psychiatrie") is the monitoring, assessment and analysis of adverse drug reactions (ADR) of psychopharmalogical drugs. We report about a 23 year-old patient with a depressive episode. He developed severe pseudohallucinations under a treatment with moclobemide. The symptoms occur 6 days after starting the medication and decline within two days after stopping moclobemide. The term "pseudohallucinations" is discussed controversially but still of high interest.

Quantitative determination of major active components in Ginkgo biloba dietary supplements by liquid chromatography/mass spectrometry.

PubMed

Ding, Shujing; Dudley, Ed; Plummer, Sue; Tang, Jiandong; Newton, Russell P; Brenton, A Gareth

2006-01-01

A reversed-phase high-performance liquid chromatography/electrospray ionisation mass spectrometry (RP-HPLC/ESI-MS) method was developed and validated for the simultaneous determination of ten major active components in Ginkgo biloba extract (bilobalide, ginkgolides A, B, C, quercetin, kaempferol, isorhamnetin, rutin hydrate, quercetin-3-beta-D-glucoside and quercitrin hydrate) which have not been previously reported to be quantified in a single analysis. The ten components exhibit baseline separation in 50 min by C18 chromatography using a water/1:1 (v/v) methanol/acetonitrile gradient. Quantitation was performed using negative ESI-MS in selected ion monitoring (SIM) mode. Good reproducibility and recovery were obtained by this method. The sensitivity of both UV and different mass spectrometry modes (full scan, selected ion monitoring (SIM), and selected reaction monitoring (SRM)) were compared and both quantitation with and without internal standard were evaluated. The analysis of Ginkgo biloba commercial products showed remarkable variations in the rutin and quercetin content as well as the terpene lactone contents although all the products satisfy the conventional quality control method. Copyright 2006 John Wiley & Sons, Ltd.

Targeted proteomics coming of age - SRM, PRM and DIA performance evaluated from a core facility perspective.

PubMed

Kockmann, Tobias; Trachsel, Christian; Panse, Christian; Wahlander, Asa; Selevsek, Nathalie; Grossmann, Jonas; Wolski, Witold E; Schlapbach, Ralph

2016-08-01

Quantitative mass spectrometry is a rapidly evolving methodology applied in a large number of omics-type research projects. During the past years, new designs of mass spectrometers have been developed and launched as commercial systems while in parallel new data acquisition schemes and data analysis paradigms have been introduced. Core facilities provide access to such technologies, but also actively support the researchers in finding and applying the best-suited analytical approach. In order to implement a solid fundament for this decision making process, core facilities need to constantly compare and benchmark the various approaches. In this article we compare the quantitative accuracy and precision of current state of the art targeted proteomics approaches single reaction monitoring (SRM), parallel reaction monitoring (PRM) and data independent acquisition (DIA) across multiple liquid chromatography mass spectrometry (LC-MS) platforms, using a readily available commercial standard sample. All workflows are able to reproducibly generate accurate quantitative data. However, SRM and PRM workflows show higher accuracy and precision compared to DIA approaches, especially when analyzing low concentrated analytes. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

A Skyline Plugin for Pathway-Centric Data Browsing

NASA Astrophysics Data System (ADS)

Degan, Michael G.; Ryadinskiy, Lillian; Fujimoto, Grant M.; Wilkins, Christopher S.; Lichti, Cheryl F.; Payne, Samuel H.

2016-11-01

For targeted proteomics to be broadly adopted in biological laboratories as a routine experimental protocol, wet-bench biologists must be able to approach selected reaction monitoring (SRM) and parallel reaction monitoring (PRM) assay design in the same way they approach biological experimental design. Most often, biological hypotheses are envisioned in a set of protein interactions, networks, and pathways. We present a plugin for the popular Skyline tool that presents public mass spectrometry data in a pathway-centric view to assist users in browsing available data and determining how to design quantitative experiments. Selected proteins and their underlying mass spectra are imported to Skyline for further assay design (transition selection). The same plugin can be used for hypothesis-driven data-independent acquisition (DIA) data analysis, again utilizing the pathway view to help narrow down the set of proteins that will be investigated. The plugin is backed by the Pacific Northwest National Laboratory (PNNL) Biodiversity Library, a corpus of 3 million peptides from >100 organisms, and the draft human proteome. Users can upload personal data to the plugin to use the pathway navigation prior to importing their own data into Skyline.

Reaction Order Ambiguity in Integrated Rate Plots

ERIC Educational Resources Information Center

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…

The reaction of H2O2 with NO2 and NO

NASA Technical Reports Server (NTRS)

Gray, D.; Lissi, E.; Heicklen, J.

1972-01-01

The reactions of NO and NO2 with H2O2 have been examined at 25 C. Reaction mixtures were monitored by continuously bleeding through a pinhole into a monopole mass spectrometer. NO2 was also monitored by its optical absorption in the visible part of the spectrum. Reaction mixtures containing initially 1.5 - 2.5 torr of NO2 and 0.8 - 1.4 torr of H2O2 or 1 - 12 torr of NO and 0.5 - 1.5 torr of H2O2 were studied. The H2O2 - NO reaction was complex. There was an induction period followed by a marked acceleration in reactant removal. The final products of the reaction, NO2, probably H2O, and possibly HONO2 were produced mainly after all the H2O2 was removed. The HONO intermediate was shown to disproportionate to NO2 + NO + H2O in a relatively slow first order reaction. The acceleration in H2O2 removal after the NO - H2O2 reaction is started is caused by NO2 catalysis.

New insight in quantitative analysis of vascular permeability during immune reaction (Conference Presentation)

NASA Astrophysics Data System (ADS)

Kalchenko, Vyacheslav; Molodij, Guillaume; Kuznetsov, Yuri; Smolyakov, Yuri; Israeli, David; Meglinski, Igor; Harmelin, Alon

2016-03-01

The use of fluorescence imaging of vascular permeability becomes a golden standard for assessing the inflammation process during experimental immune response in vivo. The use of the optical fluorescence imaging provides a very useful and simple tool to reach this purpose. The motivation comes from the necessity of a robust and simple quantification and data presentation of inflammation based on a vascular permeability. Changes of the fluorescent intensity, as a function of time is a widely accepted method to assess the vascular permeability during inflammation related to the immune response. In the present study we propose to bring a new dimension by applying a more sophisticated approach to the analysis of vascular reaction by using a quantitative analysis based on methods derived from astronomical observations, in particular by using a space-time Fourier filtering analysis followed by a polynomial orthogonal modes decomposition. We demonstrate that temporal evolution of the fluorescent intensity observed at certain pixels correlates quantitatively to the blood flow circulation at normal conditions. The approach allows to determine the regions of permeability and monitor both the fast kinetics related to the contrast material distribution in the circulatory system and slow kinetics associated with extravasation of the contrast material. Thus, we introduce a simple and convenient method for fast quantitative visualization of the leakage related to the inflammatory (immune) reaction in vivo.

Multiplexed LC-MS/MS analysis of horse plasma proteins to study doping in sport.

PubMed

Barton, Chris; Beck, Paul; Kay, Richard; Teale, Phil; Roberts, Jane

2009-06-01

The development of protein biomarkers for the indirect detection of doping in horse is a potential solution to doping threats such as gene and protein doping. A method for biomarker candidate discovery in horse plasma is presented using targeted analysis of proteotypic peptides from horse proteins. These peptides were first identified in a novel list of the abundant proteins in horse plasma. To monitor these peptides, an LC-MS/MS method using multiple reaction monitoring was developed to study the quantity of 49 proteins in horse plasma in a single run. The method was optimised and validated, and then applied to a population of race-horses to study protein variance within a population. The method was finally applied to longitudinal time courses of horse plasma collected after administration of an anabolic steroid to demonstrate utility for hypothesis-driven discovery of doping biomarker candidates.

Second Harmonic Generation Guided Raman Spectroscopy for Sensitive Detection of Polymorph Transitions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chowdhury, Azhad U.; Ye, Dong Hye; Song, Zhengtian

Second harmonic generation (SHG) was integrated with Raman spectroscopy for the analysis of pharmaceutical materials. Particulate formulations of clopidogrel bisulfate were prepared in two crystal forms (Form I and Form II). Image analysis approaches enable automated identification of particles by bright field imaging, followed by classification by SHG. Quantitative SHG microscopy enabled discrimination of crystal form on a per particle basis with 99.95% confidence in a total measurement time of ~10 ms per particle. Complementary measurements by Raman and synchrotron XRD are in excellent agreement with the classifications made by SHG, with measurement times of ~1 min and several secondsmore » per particle, respectively. Coupling these capabilities with at-line monitoring may enable real-time feedback for reaction monitoring during pharmaceutical production to favor the more bioavailable but metastable Form I with limits of detection in the ppm regime.« less

The Development and Use of Internal Amplification Controls (IACs) with DNA Profiling Kits for Forensic DNA Analysis.

PubMed

Zahra, Nathalie; Goodwin, William

2016-01-01

Biological samples recovered for forensic investigations are often degraded and/or have low amounts of DNA; in addition, in some instances the samples may be contaminated with chemicals that can act as PCR inhibitors. As a consequence this can make interpretation of the results challenging with the possibility of having partial profiles and false negative results. Because of the impact of DNA analysis on forensic investigations, it is important to monitor the process of DNA profiling, in particular the amplification reaction. In this chapter we describe a method for the in-house generation and use of internal amplification controls (IACs) with DNA profiling kits to monitor the success of the PCR proces. In the example we show the use of the SGM Plus® kit. These controls can also be used to aid the interpretation of the DNA profile.

Ultrasonic non invasive techniques for microbiological instrumentation

NASA Astrophysics Data System (ADS)

Elvira, L.; Sierra, C.; Galán, B.; Resa, P.

2010-01-01

Non invasive techniques based on ultrasounds have advantageous features to study, characterize and monitor microbiological and enzymatic reactions. These processes may change the sound speed, viscosity or particle distribution size of the medium where they take place, which makes possible their analysis using ultrasonic techniques. In this work, two different systems for the analysis of microbiological liquid media based on ultrasounds are presented. In first place, an industrial application based on an ultrasonic monitoring technique for microbiological growth detection in milk is shown. Such a system may improve the quality control strategies in food production factories, being able to decrease the time required to detect possible contaminations in packed products. Secondly, a study about the growing of the Escherichia coli DH5 α in different conditions is presented. It is shown that the use of ultrasonic non invasive characterization techniques in combination with other conventional measurements like optical density provides complementary information about the metabolism of these bacteria.

Live single cell functional phenotyping in droplet nano-liter reactors.

PubMed

Konry, Tania; Golberg, Alexander; Yarmush, Martin

2013-11-11

While single cell heterogeneity is present in all biological systems, most studies cannot address it due to technical limitations. Here we describe a nano-liter droplet microfluidic-based approach for stimulation and monitoring of surface and secreted markers of live single immune dendritic cells (DCs) as well as monitoring the live T cell/DC interaction. This nano-liter in vivo simulating microenvironment allows delivering various stimuli reagents to each cell and appropriate gas exchanges which are necessary to ensure functionality and viability of encapsulated cells. Labeling bioassay and microsphere sensors were integrated into nano-liter reaction volume of the droplet to monitor live single cell surface markers and secretion analysis in the time-dependent fashion. Thus live cell stimulation, secretion and surface monitoring can be obtained simultaneously in distinct microenvironment, which previously was possible using complicated and multi-step in vitro and in vivo live-cell microscopy, together with immunological studies of the outcome secretion of cellular function.

Study of deuteron induced reactions on natural iron and copper and their use for monitoring beam parameters and for thin layer activation technique

NASA Astrophysics Data System (ADS)

Takács, S.; Tárkányi, F.; Sonck, M.; Hermanne, A.; Sudár, S.

1997-02-01

Excitation functions of deuteron induced nuclear reactions on natural iron and copper have been studied in the frame of a systematic investigation of charged particle induced nuclear reactions on metals for different applications. The excitation functions were measured up to 20 MeV deuteron energy by using stacked foil technique and activation method. The measured and the evaluated literature data showed that some reaction can be recommended for monitoring deuteron beams, and the excitation functions can be used to determine calibration curves for Thin Layer Activation Technique (TLA). Cross sections calculated by statistical model theory, STAPRE, taking into account preequilibrium effect are in reasonable agreement with the experimental results.

Applications of fourier transform infrared spectroscopy to surface analysis problems 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, G.L.; Milosevic, M.

Applications of infrared spectroscopy to surface analysis are described in terms of the combined use of a number of techniques to solve specific surface analysis problems involving both qualitative and quantitative analysis of surface species. Emphasis is placed on the characterization of both the substrate and the surface species and the application of this to the monitoring of surface processes and the inspection of manufactured items. Lithium Hydride has been studied using remote analysis by diffuse reflectance in glove boxes containing very pure argon or controlled moisture levels with robot-operated gravimetric monitoring. These experiments are supported by internal reflectance andmore » diffuse reflectance measurements in spectrometer sample compartments to characterize the reactants. Beryllium oxide has been studied using an evacuable diffuse reflectance cell to determine the effects of vacuum baking reexposure to moisture on the surface hydroxyl species. Diffuse reflectance and emission measurements have been used to monitor the curing and reaction of environmental gases with composite materials such as graphite-expoxy structures. A direct comparison of diffuse reflectance and emission spectra was done using a barrel ellipsoid diffuse reflectance/emission detector and Spectropus optical transfer system. Grazing-incidence external-reflectance with p-polarized light was used to study the oxidation in room air of polished uranium coupons. The absorption band at 570 cm{sup {minus}1} was used to monitor the extent of oxidation with a resolution of approximately one monolayer of UO{sub 2} and to distinguish the parabolic, linear, and breakaway corrosion domains. External reflectance is compared with diffuse reflectance as a method for stain analysis and for measuring the effects of H{sub 2}O in UO{sub 2} corrosion films.« less

Applications of fourier transform infrared spectroscopy to surface analysis problems 2. Revision 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Powell, G.L.; Milosevic, M.

Applications of infrared spectroscopy to surface analysis are described in terms of the combined use of a number of techniques to solve specific surface analysis problems involving both qualitative and quantitative analysis of surface species. Emphasis is placed on the characterization of both the substrate and the surface species and the application of this to the monitoring of surface processes and the inspection of manufactured items. Lithium Hydride has been studied using remote analysis by diffuse reflectance in glove boxes containing very pure argon or controlled moisture levels with robot-operated gravimetric monitoring. These experiments are supported by internal reflectance andmore » diffuse reflectance measurements in spectrometer sample compartments to characterize the reactants. Beryllium oxide has been studied using an evacuable diffuse reflectance cell to determine the effects of vacuum baking reexposure to moisture on the surface hydroxyl species. Diffuse reflectance and emission measurements have been used to monitor the curing and reaction of environmental gases with composite materials such as graphite-expoxy structures. A direct comparison of diffuse reflectance and emission spectra was done using a barrel ellipsoid diffuse reflectance/emission detector and Spectropus optical transfer system. Grazing-incidence external-reflectance with p-polarized light was used to study the oxidation in room air of polished uranium coupons. The absorption band at 570 cm{sup {minus}1} was used to monitor the extent of oxidation with a resolution of approximately one monolayer of UO{sub 2} and to distinguish the parabolic, linear, and breakaway corrosion domains. External reflectance is compared with diffuse reflectance as a method for stain analysis and for measuring the effects of H{sub 2}O in UO{sub 2} corrosion films.« less

Aqueous-phase photooxidation of levoglucosan - a mechanistic study using aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS)

NASA Astrophysics Data System (ADS)

Zhao, R.; Mungall, E. L.; Lee, A. K. Y.; Aljawhary, D.; Abbatt, J. P. D.

2014-09-01

Levoglucosan (LG) is a widely employed tracer for biomass burning (BB). Recent studies have shown that LG can react rapidly with hydroxyl (OH) radicals in the aqueous phase despite many mass balance receptor models assuming it to be inert during atmospheric transport. In the current study, aqueous-phase photooxidation of LG by OH radicals was performed in the laboratory. The reaction kinetics and products were monitored by aerosol time-of-flight chemical ionization mass spectrometry (Aerosol ToF-CIMS). Approximately 50 reaction products were detected by the Aerosol ToF-CIMS during the photooxidation experiments, representing one of the most detailed product studies yet performed. By following the evolution of mass defects of product peaks, unique trends of adding oxygen (+O) and removing hydrogen (-2H) were observed among the products detected, providing useful information for determining potential reaction mechanisms and sequences. Additionally, bond-scission reactions take place, leading to reaction intermediates with lower carbon numbers. We introduce a data analysis framework where the average oxidation state (OSc) is plotted against a novel molecular property: double-bond-equivalence-to-carbon ratio (DBE/#C). The trajectory of LG photooxidation on this plot suggests formation of polycarbonyl intermediates and their subsequent conversion to carboxylic acids as a general reaction trend. We also determined the rate constant of LG with OH radicals at room temperature to be 1.08 ± 0.16 × 109 M-1 s-1. By coupling an aerosol mass spectrometer (AMS) to the system, we observed a rapid decay of the mass fraction of organic signals at mass-to-charge ratio 60 (f60), corresponding closely to the LG decay monitored by the Aerosol ToF-CIMS. The trajectory of LG photooxidation on a f44-f60 correlation plot matched closely to literature field measurement data. This implies that aqueous-phase photooxidation might be partially contributing to aging of BB particles in the ambient atmosphere.

Autonomous Multi-sensor Coordination: The Science Goal Monitor

NASA Technical Reports Server (NTRS)

Koratkar, Anuradha; Jung, John; Geiger, Jenny; Grosvenor, Sandy

2004-01-01

Next-generation science and exploration systems will employ new observation strategies that will use multiple sensors in a dynamic environment to provide high quality monitoring, self-consistent analyses and informed decision making. The Science Goal Monitor (SGM) is a prototype software tool being developed to explore the nature of automation necessary to enable dynamic observing of earth phenomenon. The tools being developed in SGM improve our ability to autonomously monitor multiple independent sensors and coordinate reactions to better observe the dynamic phenomena. The SGM system enables users to specify events of interest and how to react when an event is detected. The system monitors streams of data to identify occurrences of the key events previously specified by the scientist/user. When an event occurs, the system autonomously coordinates the execution of the users desired reactions between different sensors. The information can be used to rapidly respond to a variety of fast temporal events. Investigators will no longer have to rely on after-the-fact data analysis to determine what happened. Our paper describes a series of prototype demonstrations that we have developed using SGM and NASA's Earth Observing-1 (EO-1) satellite and Earth Observing Systems Aqua/Terra spacecrafts MODIS instrument. Our demonstrations show the promise of coordinating data from different sources, analyzing the data for a relevant event, autonomously updating and rapidly obtaining a follow-on relevant image. SGM is being used to investigate forest fires, floods and volcanic eruptions. We are now identifying new earth science scenarios that will have more complex SGM reasoning. By developing and testing a prototype in an operational environment, we are also establishing and gathering metrics to gauge the success of automating science campaigns.

40 CFR 264.98 - Detection monitoring program.

Code of Federal Regulations, 2010 CFR

2010-07-01

... conductance, total organic carbon, or total organic halogen), waste constituents, or reaction products that... reaction products in the unsaturated zone beneath the waste management area; (3) The detectability of indicator parameters, waste constituents, and reaction products in ground water; and (4) The concentrations...

A Computational Tool to Detect and Avoid Redundancy in Selected Reaction Monitoring

PubMed Central

Röst, Hannes; Malmström, Lars; Aebersold, Ruedi

2012-01-01

Selected reaction monitoring (SRM), also called multiple reaction monitoring, has become an invaluable tool for targeted quantitative proteomic analyses, but its application can be compromised by nonoptimal selection of transitions. In particular, complex backgrounds may cause ambiguities in SRM measurement results because peptides with interfering transitions similar to those of the target peptide may be present in the sample. Here, we developed a computer program, the SRMCollider, that calculates nonredundant theoretical SRM assays, also known as unique ion signatures (UIS), for a given proteomic background. We show theoretically that UIS of three transitions suffice to conclusively identify 90% of all yeast peptides and 85% of all human peptides. Using predicted retention times, the SRMCollider also simulates time-scheduled SRM acquisition, which reduces the number of interferences to consider and leads to fewer transitions necessary to construct an assay. By integrating experimental fragment ion intensities from large scale proteome synthesis efforts (SRMAtlas) with the information content-based UIS, we combine two orthogonal approaches to create high quality SRM assays ready to be deployed. We provide a user friendly, open source implementation of an algorithm to calculate UIS of any order that can be accessed online at http://www.srmcollider.org to find interfering transitions. Finally, our tool can also simulate the specificity of novel data-independent MS acquisition methods in Q1–Q3 space. This allows us to predict parameters for these methods that deliver a specificity comparable with that of SRM. Using SRM interference information in addition to other sources of information can increase the confidence in an SRM measurement. We expect that the consideration of information content will become a standard step in SRM assay design and analysis, facilitated by the SRMCollider. PMID:22535207

MIR-ATR sensor for process monitoring

NASA Astrophysics Data System (ADS)

Geörg, Daniel; Schalk, Robert; Methner, Frank-Jürgen; Beuermann, Thomas

2015-06-01

A mid-infrared attenuated total reflectance (MIR-ATR) sensor has been developed for chemical reaction monitoring. The optical setup of the compact and low-priced sensor consists of an IR emitter as light source, a zinc selenide (ZnSe) ATR prism as boundary to the process, and four thermopile detectors, each equipped with an optical bandpass filter. The practical applicability was tested during esterification of ethanol and formic acid to ethyl formate and water as a model reaction with subsequent distillation. For reference analysis, a Fourier transform mid-infrared (FT-MIR) spectrometer with diamond ATR module was applied. On-line measurements using the MIR-ATR sensor and the FT-MIR spectrometer were performed in a bypass loop. The sensor was calibrated by multiple linear regression in order to link the measured absorbance in the four optical channels to the analyte concentrations. The analytical potential of the MIR-ATR sensor was demonstrated by simultaneous real-time monitoring of all four chemical substances involved in the esterification and distillation process. The temporal courses of the sensor signals are in accordance with the concentration values achieved by the commercial FT-MIR spectrometer. The standard error of prediction for ethanol, formic acid, ethyl formate, and water were 0.38 mol L  -  1, 0.48 mol L  -  1, 0.38 mol L  -  1, and 1.12 mol L  -  1, respectively. A procedure based on MIR spectra is presented to simulate the response characteristics of the sensor if the transmission ranges of the filters are varied. Using this tool analyte specific bandpass filters for a particular chemical reaction can be identified. By exchanging the optical filters, the sensor can be adapted to a wide range of processes in the chemical, pharmaceutical, and beverage industries.

Genomic characterization of Indian isolates of egg drop syndrome 1976 virus.

PubMed

Raj, G D; Sivakumar, S; Sudharsan, S; Mohan, A C; Nachimuthu, K

2001-02-01

Five Indian isolates of egg drop syndrome (EDS) 1976 virus and the reference strain 127 were compared by restriction enzyme analysis of viral DNA, and the hexon gene amplified by polymerase chain reaction. Using these techniques, no differences were seen among these viruses. However, partial sequencing of the hexon gene revealed major differences (4.6%) in one of the isolates sequenced, EDS Kerala. Phylogenetic analysis also placed this isolate in a different lineage compared with the other isolates. The need for constant monitoring of the genetic nature of the field isolates of EDS viruses is emphasized.

Reactions and mass spectra of complex particles using Aerosol CIMS

NASA Astrophysics Data System (ADS)

Hearn, John D.; Smith, Geoffrey D.

2006-12-01

Aerosol chemical ionization mass spectrometry (CIMS) is used both on- and off-line for the analysis of complex laboratory-generated and ambient particles. One of the primary advantages of Aerosol CIMS is the low degree of ion fragmentation, making this technique well suited for investigating the reactivity of complex particles. To demonstrate the usefulness of this "soft" ionization, particles generated from meat cooking were reacted with ozone and the composition was monitored as a function of reaction time. Two distinct kinetic regimes were observed with most of the oleic acid in these particles reacting quickly but with 30% appearing to be trapped in the complex mixture. Additionally, detection limits are measured to be sufficiently low (100-200 ng/m3) to detect some of the more abundant constituents in ambient particles, including sulfate, which is measured in real-time at 1.2 [mu]g/m3. To better characterize complex aerosols from a variety of sources, a novel off-line collection method was also developed in which non-volatile and semi-volatile organics are desorbed from particles and concentrated in a cold U-tube. Desorption from the U-tube followed by analysis with Aerosol CIMS revealed significant amounts of nicotine in cigarette smoke and levoglucosan in oak and pine smoke, suggesting that this may be a useful technique for monitoring particle tracer species. Additionally, secondary organic aerosol formed from the reaction of ozone with R-limonene and volatile organics from orange peel were analyzed off-line showing large molecular weight products (m/z > 300 amu) that may indicate the formation of oligomers. Finally, mass spectra of ambient aerosol collected offline reveal a complex mixture of what appears to be highly processed organics, some of which may contain nitrogen.

Value of information analysis for groundwater quality monitoring network design Case study: Eocene Aquifer, Palestine

NASA Astrophysics Data System (ADS)

Khader, A.; McKee, M.

2010-12-01

Value of information (VOI) analysis evaluates the benefit of collecting additional information to reduce or eliminate uncertainty in a specific decision-making context. It makes explicit any expected potential losses from errors in decision making due to uncertainty and identifies the “best” information collection strategy as one that leads to the greatest expected net benefit to the decision-maker. This study investigates the willingness to pay for groundwater quality monitoring in the Eocene Aquifer, Palestine, which is an unconfined aquifer located in the northern part of the West Bank. The aquifer is being used by 128,000 Palestinians to fulfill domestic and agricultural demands. The study takes into account the consequences of pollution and the options the decision maker might face. Since nitrate is the major pollutant in the aquifer, the consequences of nitrate pollution were analyzed, which mainly consists of the possibility of methemoglobinemia (blue baby syndrome). In this case, the value of monitoring was compared to the costs of treating for methemoglobinemia or the costs of other options like water treatment, using bottled water or importing water from outside the aquifer. And finally, an optimal monitoring network that takes into account the uncertainties in recharge (climate), aquifer properties (hydraulic conductivity), pollutant chemical reaction (decay factor), and the value of monitoring is designed by utilizing a sparse Bayesian modeling algorithm called a relevance vector machine.

Preliminary measurements of neutrons from the D-D reaction in the COMPASS tokamak

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dankowski, J., E-mail: jan.dankowski@ifj.edu.pl; Kurowski, A.; Twarog, D.

Recent results of measured fast neutrons created in the D-D reaction on the COMPASS tokamak during ohmic discharges are presented in this paper. Two different type detectors were used during experiment. He-3 detectors and bubble detectors as a support. The measurements are an introduction for neutron diagnostic on tokamak COMPASS and monitoring neutrons during discharges with Neutral Beam Injection (NBI). The He-3 counters and bubble detectors were located in two positions near tokamak vacuum chamber at a distance less than 40 cm to the centre of plasma. The neutrons flux was observed in ohmic discharges. However, analysis of our resultsmore » does not indicate any clear source of neutrons production during ohmic discharges.« less

Science Goal Monitor: Science Goal Driven Automation for NASA Missions

NASA Technical Reports Server (NTRS)

Koratkar, Anuradha; Grosvenor, Sandy; Jung, John; Pell, Melissa; Matusow, David; Bailyn, Charles

2004-01-01

Infusion of automation technologies into NASA s future missions will be essential because of the need to: (1) effectively handle an exponentially increasing volume of scientific data, (2) successfully meet dynamic, opportunistic scientific goals and objectives, and (3) substantially reduce mission operations staff and costs. While much effort has gone into automating routine spacecraft operations to reduce human workload and hence costs, applying intelligent automation to the science side, i.e., science data acquisition, data analysis and reactions to that data analysis in a timely and still scientifically valid manner, has been relatively under-emphasized. In order to introduce science driven automation in missions, we must be able to: capture and interpret the science goals of observing programs, represent those goals in machine interpretable language; and allow spacecrafts onboard systems to autonomously react to the scientist's goals. In short, we must teach our platforms to dynamically understand, recognize, and react to the scientists goals. The Science Goal Monitor (SGM) project at NASA Goddard Space Flight Center is a prototype software tool being developed to determine the best strategies for implementing science goal driven automation in missions. The tools being developed in SGM improve the ability to monitor and react to the changing status of scientific events. The SGM system enables scientists to specify what to look for and how to react in descriptive rather than technical terms. The system monitors streams of science data to identify occurrences of key events previously specified by the scientist. When an event occurs, the system autonomously coordinates the execution of the scientist s desired reactions. Through SGM, we will improve om understanding about the capabilities needed onboard for success, develop metrics to understand the potential increase in science returns, and develop an operational prototype so that the perceived risks associated with increased use of automation can be reduced.

System and process for pulsed multiple reaction monitoring

DOEpatents

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.

Clinical application analysis of andrographolide total ester sulfonate injection, a traditional Chinese medicine licensed in China.

PubMed

Zhao, Ying; Huang, Pu; Chen, Zhe; Zheng, Si-Wei; Yu, Jin-Yang; Shi, Chen

2017-04-01

Andrographolide total ester sulfonate (ATES) injection is one of the products of traditional Chinese medicine (TCM) currently used against viral infection in China. ATES injection was approved for manufacturing and marketing in January 2002. It is indicated for acute respiratory infections, tonsillitis, chronic obstructive pulmonary disease, influenza, foot and mouth disease, bronchiolitis, herpangina, mumps, infectious mononucleosis and psychosis. However, its usage also carries risk. We investigated the use of ATES at the Wuhan Union Hospital from January 2014 to December 2014 and evaluated its real-world clinical application using the hospital centralized monitoring method. A total of 848 cases were enrolled in this study. In these cases, it was mainly used for postoperative anti-inflammation and treating upper respiratory infection, pneumonia and bronchitis. Among them, 39.86% were contraindicated. Irregular medication of adults and children accounted for 1.91% and 23.38%, respectively. Improper choice of solvent accounted for 3.18%. The choice of intravenous drip versus aerosol inhalation was reasonable. A case of adverse events (AEs) was observed in the monitoring period, and the incidence of adverse drug reaction (ADR) of ATES injection was 0.12%. ATES injection in our hospital is relatively safe with a low incidence of adverse reactions. The study assesses the clinical usage and adverse reactions of ATES injection, and provides suggestions for rational use in clinical practice.

Schreibersite: an effective catalyst in the formose reaction network

NASA Astrophysics Data System (ADS)

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.

Radioactive Phosphorylation of Alcohols to Monitor Biocatalytic Diels-Alder Reactions

PubMed Central

Nierth, Alexander; Jäschke, Andres

2011-01-01

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. PMID:21731729

A novel microbial fuel cell sensor with a gas diffusion biocathode sensing element for water and air quality monitoring.

PubMed

Jiang, Yong; Liang, Peng; Huang, Xia; Ren, Zhiyong Jason

2018-07-01

Toxicity monitoring is essential for the protection of public health and ecological safety. Microbial fuel cell (MFC) sensors demonstrated good potential in toxicity monitoring, but current MFC sensors can only be used for anaerobic water monitoring. In this study, a novel gas diffusion (GD)-biocathode sensing element was fabricated using a simple method. The GD-biocathode MFC sensor can directly be used for formaldehyde detection (from 0.0005% to 0.005%) in both aerobic and anaerobic water bodies. Electrochemical analysis indicated that the response by the sensor was caused by the toxic inhibition to the microbial activity for the oxygen reduction reaction (ORR). This study for the first time demonstrated that the GD-biocathode MFC sensor has a detection limit of 20 ppm for formaldehyde and can be used to monitor air pollution. Selective sensitivity to formaldehyde was not achieved as the result of using a mixed-culture, which confirms that it can serve as a generic biosensor for monitoring gaseous pollutants. This study expands the realm of knowledge for MFC sensor applications. Copyright © 2018 Elsevier Ltd. All rights reserved.

Mapping the Complete Reaction Path of a Complex Photochemical Reaction.

PubMed

Smith, Adam D; Warne, Emily M; Bellshaw, Darren; Horke, Daniel A; Tudorovskya, Maria; Springate, Emma; Jones, Alfred J H; Cacho, Cephise; Chapman, Richard T; Kirrander, Adam; Minns, Russell S

2018-05-04

We probe the dynamics of dissociating CS_{2} molecules across the entire reaction pathway upon excitation. Photoelectron spectroscopy measurements using laboratory-generated femtosecond extreme ultraviolet pulses monitor the competing dissociation, internal conversion, and intersystem crossing dynamics. Dissociation occurs either in the initially excited singlet manifold or, via intersystem crossing, in the triplet manifold. Both product channels are monitored and show that, despite being more rapid, the singlet dissociation is the minor product and that triplet state products dominate the final yield. We explain this by a consideration of accurate potential energy curves for both the singlet and triplet states. We propose that rapid internal conversion stabilizes the singlet population dynamically, allowing for singlet-triplet relaxation via intersystem crossing and the efficient formation of spin-forbidden dissociation products on longer timescales. The study demonstrates the importance of measuring the full reaction pathway for defining accurate reaction mechanisms.

Mapping the Complete Reaction Path of a Complex Photochemical Reaction

NASA Astrophysics Data System (ADS)

Smith, Adam D.; Warne, Emily M.; Bellshaw, Darren; Horke, Daniel A.; Tudorovskya, Maria; Springate, Emma; Jones, Alfred J. H.; Cacho, Cephise; Chapman, Richard T.; Kirrander, Adam; Minns, Russell S.

2018-05-01

We probe the dynamics of dissociating CS2 molecules across the entire reaction pathway upon excitation. Photoelectron spectroscopy measurements using laboratory-generated femtosecond extreme ultraviolet pulses monitor the competing dissociation, internal conversion, and intersystem crossing dynamics. Dissociation occurs either in the initially excited singlet manifold or, via intersystem crossing, in the triplet manifold. Both product channels are monitored and show that, despite being more rapid, the singlet dissociation is the minor product and that triplet state products dominate the final yield. We explain this by a consideration of accurate potential energy curves for both the singlet and triplet states. We propose that rapid internal conversion stabilizes the singlet population dynamically, allowing for singlet-triplet relaxation via intersystem crossing and the efficient formation of spin-forbidden dissociation products on longer timescales. The study demonstrates the importance of measuring the full reaction pathway for defining accurate reaction mechanisms.

Highly efficient and selective pressure-assisted photon-induced polymerization of styrene

NASA Astrophysics Data System (ADS)

Guan, Jiwen; Song, Yang

2016-06-01

The polymerization process of condensed styrene to produce polystyrene as an industrially important polymeric material was investigated using a novel approach by combining external compression with ultraviolet radiation. The reaction evolution was monitored as a function of time and the reaction products were characterized by in situ Fourier transform infrared spectroscopy. By optimizing the loading pressures, we observed highly efficient and selective production of polystyrene of different tacticities. Specifically, at relatively low loading pressures, infrared spectra suggest that styrene monomers transform to amorphous atactic polystyrene (APS) with minor crystalline isotactic polystyrene. In contrast, APS was found to be the sole product when polymerization occurs at relatively higher loading pressures. The time-dependent reaction profiles allow the examination of the polymerization kinetics by analyzing the rate constant and activation volume as a function of pressure. As a result, an optimized pressure condition, which allows a barrierless reaction to proceed, was identified and attributed to the very desirable reaction yield and kinetics. Finally, the photoinitiated reaction mechanism and the growth geometry of the polymer chains were investigated from the energy diagram of styrene and by the topology analysis of the crystal styrene. This study shows strong promise to produce functional polymeric materials in a highly efficient and controlled manner.

Facial reactions to violent and comedy films: Association with callous-unemotional traits and impulsive aggression.

PubMed

Fanti, Kostas A; Kyranides, Melina Nicole; Panayiotou, Georgia

2017-02-01

The current study adds to prior research by investigating specific (happiness, sadness, surprise, disgust, anger and fear) and general (corrugator and zygomatic muscle activity) facial reactions to violent and comedy films among individuals with varying levels of callous-unemotional (CU) traits and impulsive aggression (IA). Participants at differential risk of CU traits and IA were selected from a sample of 1225 young adults. In Experiment 1, participants (N = 82) facial expressions were recorded while they watched violent and comedy films. Video footage of participants' facial expressions was analysed using FaceReader, a facial coding software that classifies facial reactions. Findings suggested that individuals with elevated CU traits showed reduced facial reactions of sadness and disgust to violent films, indicating low empathic concern in response to victims' distress. In contrast, impulsive aggressors produced specifically more angry facial expressions when viewing violent and comedy films. In Experiment 2 (N = 86), facial reactions were measured by monitoring facial electromyography activity. FaceReader findings were verified by the reduced facial electromyography at the corrugator, but not the zygomatic, muscle in response to violent films shown by individuals high in CU traits. Additional analysis suggested that sympathy to victims explained the association between CU traits and reduced facial reactions to violent films.

Nitrogen-Containing Low Volatile Compounds from Pinonaldehyde-Dimethylamine Reaction in the Atmosphere: A Laboratory and Field Study.

PubMed

Duporté, Geoffroy; Parshintsev, Jevgeni; Barreira, Luís M F; Hartonen, Kari; Kulmala, Markku; Riekkola, Marja-Liisa

2016-05-03

Pinonaldehyde, which is among the most abundant oxidation products of α-pinene, and dimethylamine were selected to study the formation of N-containing low volatile compounds from aldehyde-amine reactions in the atmosphere. Gas phase reactions took place in a Tedlar bag, which was connected to a mass spectrometer ionization source via a short deactivated fused silica column. In addition to on-line analysis, abundance of gaseous precursors and reaction products were monitored off-line. Condensable products were extracted from the bag's walls with a suitable solvent and analyzed by gas chromatography coupled to chemical ionization high-resolution quadrupole time-of-flight mass spectrometry and by ultra-high-performance liquid chromatography coupled to electrospray ionization Orbitrap mass spectrometry. The reactions carried out resulted in several mid-low vapor pressure nitrogen-containing compounds that are potentially important for the formation of secondary organic aerosols in the atmosphere. Further, the presence of brown carbon, confirmed by liquid chromatography-UV-vis-mass spectrometry, was observed. Some of the compounds identified in the laboratory study were also observed in aerosol samples collected at SMEAR II station (Hyytiälä, Finland) in August 2015 suggesting the importance of aldehyde-amine reactions for the aerosol formation and growth.

Confocal Raman microscopy for monitoring chemical reactions on single optically trapped, solid-phase support particles.

PubMed

Houlne, Michael P; Sjostrom, Christopher M; Uibel, Rory H; Kleimeyer, James A; Harris, Joel M

2002-09-01

Optical trapping of small structures is a powerful tool for the manipulation and investigation of colloidal and particulate materials. The tight focus excitation requirements of optical trapping are well suited to confocal Raman microscopy. In this work, an inverted confocal Raman microscope is developed for studies of chemical reactions on single, optically trapped particles and applied to reactions used in solid-phase peptide synthesis. Optical trapping and levitation allow a particle to be moved away from the coverslip and into solution, avoiding fluorescence interference from the coverslip. More importantly, diffusion of reagents into the particle is not inhibited by a surface, so that reaction conditions mimic those of particles dispersed in solution. Optical trapping and levitation also maintain optical alignment, since the particle is centered laterally along the optical axis and within the focal plane of the objective, where both optical forces and light collection are maximized. Hour-long observations of chemical reactions on individual, trapped silica particles are reported. Using two-dimensional least-squares analysis methods, the Raman spectra collected during the course of a reaction can be resolved into component contributions. The resolved spectra of the time-varying species can be observed, as they bind to or cleave from the particle surface.

Quantitative analysis of microbial biomass yield in aerobic bioreactor.

PubMed

Watanabe, Osamu; Isoda, Satoru

2013-12-01

We have studied the integrated model of reaction rate equations with thermal energy balance in aerobic bioreactor for food waste decomposition and showed that the integrated model has the capability both of monitoring microbial activity in real time and of analyzing biodegradation kinetics and thermal-hydrodynamic properties. On the other hand, concerning microbial metabolism, it was known that balancing catabolic reactions with anabolic reactions in terms of energy and electron flow provides stoichiometric metabolic reactions and enables the estimation of microbial biomass yield (stoichiometric reaction model). We have studied a method for estimating real-time microbial biomass yield in the bioreactor during food waste decomposition by combining the integrated model with the stoichiometric reaction model. As a result, it was found that the time course of microbial biomass yield in the bioreactor during decomposition can be evaluated using the operational data of the bioreactor (weight of input food waste and bed temperature) by the combined model. The combined model can be applied to manage a food waste decomposition not only for controlling system operation to keep microbial activity stable, but also for producing value-added products such as compost on optimum condition. Copyright © 2013 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Comparison of Protein Immunoprecipitation-Multiple Reaction Monitoring with ELISA for Assay of Biomarker Candidates in Plasma

PubMed Central

2013-01-01

Quantitative analysis of protein biomarkers in plasma is typically done by ELISA, but this method is limited by the availability of high-quality antibodies. An alternative approach is protein immunoprecipitation combined with multiple reaction monitoring mass spectrometry (IP-MRM). We compared IP-MRM to ELISA for the analysis of six colon cancer biomarker candidates (metalloproteinase inhibitor 1 (TIMP1), cartilage oligomeric matrix protein (COMP), thrombospondin-2 (THBS2), endoglin (ENG), mesothelin (MSLN) and matrix metalloproteinase-9 (MMP9)) in plasma from colon cancer patients and noncancer controls. Proteins were analyzed by multiplex immunoprecipitation from plasma with the ELISA capture antibodies, further purified by SDS-PAGE, digested and analyzed by stable isotope dilution MRM. IP-MRM provided linear responses (r = 0.978–0.995) between 10 and 640 ng/mL for the target proteins spiked into a “mock plasma” matrix consisting of 60 mg/mL bovine serum albumin. Measurement variation (coefficient of variation at the limit of detection) for IP-MRM assays ranged from 2.3 to 19%, which was similar to variation for ELISAs of the same samples. IP-MRM and ELISA measurements for all target proteins except ENG were highly correlated (r = 0.67–0.97). IP-MRM with high-quality capture antibodies thus provides an effective alternative method to ELISA for protein quantitation in biological fluids. PMID:24224610

Targeted quantitative analysis of Streptococcus pyogenes virulence factors by multiple reaction monitoring.

PubMed

Lange, Vinzenz; Malmström, Johan A; Didion, John; King, Nichole L; Johansson, Björn P; Schäfer, Juliane; Rameseder, Jonathan; Wong, Chee-Hong; Deutsch, Eric W; Brusniak, Mi-Youn; Bühlmann, Peter; Björck, Lars; Domon, Bruno; Aebersold, Ruedi

2008-08-01

In many studies, particularly in the field of systems biology, it is essential that identical protein sets are precisely quantified in multiple samples such as those representing differentially perturbed cell states. The high degree of reproducibility required for such experiments has not been achieved by classical mass spectrometry-based proteomics methods. In this study we describe the implementation of a targeted quantitative approach by which predetermined protein sets are first identified and subsequently quantified at high sensitivity reliably in multiple samples. This approach consists of three steps. First, the proteome is extensively mapped out by multidimensional fractionation and tandem mass spectrometry, and the data generated are assembled in the PeptideAtlas database. Second, based on this proteome map, peptides uniquely identifying the proteins of interest, proteotypic peptides, are selected, and multiple reaction monitoring (MRM) transitions are established and validated by MS2 spectrum acquisition. This process of peptide selection, transition selection, and validation is supported by a suite of software tools, TIQAM (Targeted Identification for Quantitative Analysis by MRM), described in this study. Third, the selected target protein set is quantified in multiple samples by MRM. Applying this approach we were able to reliably quantify low abundance virulence factors from cultures of the human pathogen Streptococcus pyogenes exposed to increasing amounts of plasma. The resulting quantitative protein patterns enabled us to clearly define the subset of virulence proteins that is regulated upon plasma exposure.

High mass accuracy assay for trimethylamine N-oxide using stable-isotope dilution with liquid chromatography coupled to orthogonal acceleration time of flight mass spectrometry with multiple reaction monitoring.

PubMed

Heaney, Liam M; Jones, Donald J L; Mbasu, Richard J; Ng, Leong L; Suzuki, Toru

2016-01-01

Trimethylamine N-oxide (TMAO) has attracted interest as circulating levels have reported prognostic value in patients with cardiovascular conditions, such as heart failure. With continual advances in accurate mass measurements, robust methods that can employ the capabilities of time of flight mass spectrometers would offer additional utility in the analysis of complex clinical samples. A Waters Acquity UPLC was coupled to a Waters Synapt G2-S high-resolution mass spectrometer. TMAO was measured in plasma by stable-isotope dilution-hydrophilic interaction liquid chromatography-time of flight mass spectrometry with multiple reaction monitoring (LC-ToF-MRM). Two transitions were monitored: m/z 76.1 to 58.066/59.073 and m/z 85.1 to 66.116/68.130. The method was assessed for linearity, lower limits of detection and quantitation, and reproducibility. A selected cohort of patients with systolic heart failure (SHF; n = 43) and healthy controls (n = 42) were measured to verify the assay is suitable for the analysis of clinical samples. Quantitative analysis of TMAO using LC-ToF-MRM enabled linearity to be established between 0.1 and 75 μmol/L, with a lower limit of detection of 0.05 μmol/L. Relative standard deviations reported an inter-day variation of ≤20.8% and an intra-day variation of ≤11.4% with an intra-study quality control variation of 2.7%. Run times were 2.5 min. Clinical application of the method reported that TMAO in SHF was elevated compared to that of healthy controls (p < 0.0005). LC-ToF-MRM offers a highly selective method for accurate mass measurement of TMAO with rapid and reproducible results. Applicability of the method was shown in a selected cohort of patient samples.

On-line miniaturized asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry with selected reaction monitoring for quantitative analysis of phospholipids in plasma lipoproteins.

PubMed

Yang, Iseul; Kim, Ki Hun; Lee, Ju Yong; Moon, Myeong Hee

2014-01-10

A direct analytical method for high speed quantitative analysis of lipids in human blood plasma using on-line chip-type asymmetrical flow field-flow fractionation-electrospray ionization-tandem mass spectrometry (cAF4-ESI-MS/MS) with selected reaction monitoring (SRM) is described in this study. Utilizing a miniaturized cAF4 channel, high speed size separation of high density lipoproteins (HDL) and low density lipoproteins (LDL) from plasma samples can be accomplished at a microflow rate along with simultaneous desalting of lipoproteins, both of which are conducive to direct ESI of lipids in lipoproteins. This study demonstrates that the SRM method to monitor phospholipids during cAF4-ESI-MS/MS can be successfully applied to the quantitation of lipid molecules in plasma lipoproteins without the need of a separate lipid extraction process. For quantitation of lipids in HDL and LDL during cAF4-ESI-MS/MS runs, a protein standard (carbonic anhydrase, 29 kDa) was added to each plasma sample as an internal standard such that a peak intensity of y67(+5) ions, which are high abundant SRM product ions of CA, could be utilized to calculate the relative intensity of each lipid molecule. The developed method was applied to plasma samples from 10 patients with coronary artery disease (CAD) and 10 healthy control samples, and quantitative analysis of 39 lipid molecules including phosphatidylcholines, phosphatidylethanolamines, sphingomyelins, phosphatidylglycerols, and phosphatidylinositols, resulted in the selection of 13 PL species showing more than 2.5 fold difference in relative abundance (p<0.01) between the groups. The present study demonstrates a high speed analytical method for determining plasma lipid content and distribution without an organic solvent extraction of lipids from plasma. Copyright © 2013 Elsevier B.V. All rights reserved.

Fast methods for analysis of neurotransmitters from single cell and monitoring their releases in central nervous system by capillary electrophoresis, fluorescence microscopy and luminescence imaging

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Ziqiang

1999-12-10

Fast methods for separation and detection of important neurotransmitters and the releases in central nervous system (CNS) were developed. Enzyme based immunoassay combined with capillary electrophoresis was used to analyze the contents of amino acid neurotransmitters from single neuron cells. The release of amino acid neurotransmitters from neuron cultures was monitored by laser induced fluorescence imaging method. The release and signal transduction of adenosine triphosphate (ATP) in CNS was studied with sensitive luminescence imaging method. A new dual-enzyme on-column reaction method combined with capillary electrophoresis has been developed for determining the glutamate content in single cells. Detection was based onmore » monitoring the laser-induced fluorescence of the reaction product NADH, and the measured fluorescence intensity was related to the concentration of glutamate in each cell. The detection limit of glutamate is down to 10 -8 M level, which is 1 order of magnitude lower than the previously reported detection limit based on similar detection methods. The mass detection limit of a few attomoles is far superior to that of any other reports. Selectivity for glutamate is excellent over most of amino acids. The glutamate content in single human erythrocyte and baby rat brain neurons were determined with this method and results agreed well with literature values.« less

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

PubMed

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.

Life Span Differences in Electrophysiological Correlates of Monitoring Gains and Losses during Probabilistic Reinforcement Learning

ERIC Educational Resources Information Center

Hammerer, Dorothea; Li, Shu-Chen; Muller, Viktor; Lindenberger, Ulman

2011-01-01

By recording the feedback-related negativity (FRN) in response to gains and losses, we investigated the contribution of outcome monitoring mechanisms to age-associated differences in probabilistic reinforcement learning. Specifically, we assessed the difference of the monitoring reactions to gains and losses to investigate the monitoring of…

pH-sensitive pHluorins as a molecular sensor for in situ monitoring of enzyme-catalyzed prodrug activation.

PubMed

Liu, Hui; Cao, Xiaodan; Wang, Ping; Ma, Xingyuan

2017-07-01

This work examines the feasibility of using a pH-sensitive fluorescent protein as a molecular reporter for enzyme-catalyzed prodrug activation reaction. Specifically, a ratiometric pHluorins was examined for detection of the activity of horseradish peroxidase (HRP) for the activation of indole-3-acetic acid. The pHluorins and HRP were conjugated chemically, forming a biocatalyst with a self-reporting function. Results showed that the characteristic fluorescence intensity ratio of the conjugate shifted from 1.47 to 1.40 corresponding to the progress of the prodrug activation reaction. The effectiveness of applying the conjugate for inhibition of the growth of Bcap-37 cells was also demonstrated simultaneously with reaction monitoring. The results reveal a very promising approach to realizing in situ monitoring of enzyme activities based on pH shifting for enzyme-based prodrug therapy applications. © 2016 International Union of Biochemistry and Molecular Biology, Inc.

Raman spectroscopic approach to monitor the in vitro cyclization of creatine → creatinine

NASA Astrophysics Data System (ADS)

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.

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

PubMed Central

Julien, Patrick A; Malvestiti, Ivani

2017-01-01

We provide the first in situ and real-time study of the effect of milling frequency on the course of a mechanochemical organic reaction conducted using a vibratory shaker (mixer) ball mill. The use of in situ Raman spectroscopy for real-time monitoring of the mechanochemical synthesis of a 2,3-diphenylquinoxaline derivative revealed a pronounced dependence of chemical reactivity on small variations in milling frequency. In particular, in situ measurements revealed the establishment of two different regimes of reaction kinetics at different frequencies, providing tentative insight into processes of mechanical activation in organic mechanochemical synthesis. PMID:29114323

Crystallization Kinetics of an Amorphous Pharmaceutical Compound Using Fluorescence-Lifetime-Imaging Microscopy.

PubMed

Rautaniemi, Kaisa; Vuorimaa-Laukkanen, Elina; Strachan, Clare J; Laaksonen, Timo

2018-05-07

Pharmaceutical scientists are increasingly interested in amorphous drug formulations especially because of their higher dissolution rates. Consequently, the thorough characterization and analysis of these formulations are becoming more and more important for the pharmaceutical industry. Here, fluorescence-lifetime-imaging microscopy (FLIM) was used to monitor the crystallization of an amorphous pharmaceutical compound, indomethacin. Initially, we identified different solid indomethacin forms, amorphous and γ- and α-crystalline, on the basis of their time-resolved fluorescence. All of the studied indomethacin forms showed biexponential decays with characteristic fluorescence lifetimes and amplitudes. Using this information, the crystallization of amorphous indomethacin upon storage in 60 °C was monitored for 10 days with FLIM. The progress of crystallization was detected as lifetime changes both in the FLIM images and in the fluorescence-decay curves extracted from the images. The fluorescence-lifetime amplitudes were used for quantitative analysis of the crystallization process. We also demonstrated that the fluorescence-lifetime distribution of the sample changed during crystallization, and when the sample was not moved between measuring times, the lifetime distribution could also be used for the analysis of the reaction kinetics. Our results clearly show that FLIM is a sensitive and nondestructive method for monitoring solid-state transformations on the surfaces of fluorescent samples.

Biomarker discovery and transcriptomic responses in Daphnia magna exposed to munitions constituents.

PubMed

Garcia-Reyero, Natalia; Poynton, Helen C; Kennedy, Alan J; Guan, Xin; Escalon, B Lynn; Chang, Bonnie; Varshavsky, Julia; Loguinov, Alex V; Vulpe, Chris D; Perkins, Edward J

2009-06-01

Ecotoxicogenomic approaches are emerging as alternative methods in environmental monitoring because they allow insight into pollutant modes of action and help assess the causal agents and potential toxicity beyond the traditional end points of death, growth, and reproduction. Gene expression analysis has shown particular promise for identifying gene expression biomarkers of chemical exposure that can be further used to monitor specific chemical exposures in the environment. We focused on the development of gene expression markers to detect and discriminate between chemical exposures. Using a custom cDNA microarray for Daphnia magna, we identified distinct expression fingerprints in response to exposure at sublethal concentrations of Cu, Zn, Pb, and munitions constituents. Using the results obtained from microarray analysis, we chose a suite of potential biomarkers for each of the specific exposures. The selected potential biomarkers were tested in independent chemical exposures for specificity using quantitative reverse transcription polymerase chain reaction. Six genes were confirmed as differentially regulated bythe selected chemical exposures. Furthermore, each exposure was identified by response of a unique combination (suite) of individual gene expression biomarkers. These results demonstrate the potential for discovery and validation of novel biomarkers of chemical exposures using gene expression analysis, which could have broad applicability in environmental monitoring.

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

PubMed

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.

Ionization signals from diamond detectors in fast-neutron fields

NASA Astrophysics Data System (ADS)

Weiss, C.; Frais-Kölbl, H.; Griesmayer, E.; Kavrigin, P.

2016-09-01

In this paper we introduce a novel analysis technique for measurements with single-crystal chemical vapor deposition (sCVD) diamond detectors in fast-neutron fields. This method exploits the unique electronic property of sCVD diamond sensors that the signal shape of the detector current is directly proportional to the initial ionization profile. In fast-neutron fields the diamond sensor acts simultaneously as target and sensor. The interaction of neutrons with the stable isotopes 12 C and 13 C is of interest for fast-neutron diagnostics. The measured signal shapes of detector current pulses are used to identify individual types of interactions in the diamond with the goal to select neutron-induced reactions in the diamond and to suppress neutron-induced background reactions as well as γ-background. The method is verified with experimental data from a measurement in a 14.3 MeV neutron beam at JRC-IRMM, Geel/Belgium, where the 13C(n, α)10Be reaction was successfully extracted from the dominating background of recoil protons and γ-rays and the energy resolution of the 12C(n, α)9Be reaction was substantially improved. The presented analysis technique is especially relevant for diagnostics in harsh radiation environments, like fission and fusion reactors. It allows to extract the neutron spectrum from the background, and is particularly applicable to neutron flux monitoring and neutron spectroscopy.

Tools to minimize interlaboratory variability in vitellogenin gene expression monitoring programs

USGS Publications Warehouse

Jastrow, Aaron; Gordon, Denise A.; Auger, Kasie M.; Punska, Elizabeth C.; Arcaro, Kathleen F.; Keteles, Kristen; Winkelman, Dana L.; Lattier, David; Biales, Adam; Lazorchak, James M.

2017-01-01

The egg yolk precursor protein vitellogenin is widely used as a biomarker of estrogen exposure in male fish. However, standardized methodology is lacking and little is known regarding the reproducibility of results among laboratories using different equipment, reagents, protocols, and data analysis programs. To address this data gap we tested the reproducibility across laboratories to evaluate vitellogenin gene (vtg) expression and assessed the value of using a freely available software data analysis program. Samples collected from studies of male fathead minnows (Pimephales promelas) exposed to 17α-ethinylestradiol (EE2) and minnows exposed to processed wastewater effluent were evaluated for vtg expression in 4 laboratories. Our results indicate reasonable consistency among laboratories if the free software for expression analysis LinRegPCR is used, with 3 of 4 laboratories detecting vtg in fish exposed to 5 ng/L EE2 (n = 5). All 4 laboratories detected significantly increased vtg levels in 15 male fish exposed to wastewater effluent compared with 15 male fish held in a control stream. Finally, we were able to determine that the source of high interlaboratory variability from complementary deoxyribonucleic acid (cDNA) to quantitative polymerase chain reaction (qPCR) analyses was the expression analysis software unique to each real-time qPCR machine. We successfully eliminated the interlaboratory variability by reanalyzing raw fluorescence data with independent freeware, which yielded cycle thresholds and polymerase chain reaction (PCR) efficiencies that calculated results independently of proprietary software. Our results suggest that laboratories engaged in monitoring programs should validate their PCR protocols and analyze their gene expression data following the guidelines established in the present study for all gene expression biomarkers. 

Application of adenosine triphosphate affinity probe and scheduled multiple-reaction monitoring analysis for profiling global kinome in human cells in response to arsenite treatment.

PubMed

Guo, Lei; Xiao, Yongsheng; Wang, Yinsheng

2014-11-04

Phosphorylation of cellular components catalyzed by kinases plays important roles in cell signaling and proliferation. Quantitative assessment of perturbation in global kinome may provide crucial knowledge for elucidating the mechanisms underlying the cytotoxic effects of environmental toxicants. Here, we utilized an adenosine triphosphate (ATP) affinity probe coupled with stable isotope labeling by amino acids in cell culture (SILAC) to assess quantitatively the arsenite-induced alteration of global kinome in human cells. We constructed a SILAC-compatible kinome library for scheduled multiple-reaction monitoring (MRM) analysis and adopted on-the-fly recalibration of retention time shift, which provided better throughput of the analytical method and enabled the simultaneous quantification of the expression of ∼300 kinases in two LC-MRM runs. With this improved analytical method, we conducted an in-depth quantitative analysis of the perturbation of kinome of GM00637 human skin fibroblast cells induced by arsenite exposure. Several kinases involved in cell cycle progression, including cyclin-dependent kinases (CDK1 and CDK4) and Aurora kinases A, B, and C, were found to be hyperactivated, and the altered expression of CDK1 was further validated by Western analysis. In addition, treatment with a CDK inhibitor, flavopiridol, partially restored the arsenite-induced growth inhibition of human skin fibroblast cells. Thus, sodium arsenite may confer its cytotoxic effect partly through the aberrant activation of CDKs and the resultant perturbation of cell cycle progression. Together, we developed a high-throughput, SILAC-compatible, and MRM-based kinome profiling method and demonstrated that the method is powerful in deciphering the molecular modes of action of a widespread environmental toxicant. The method should be generally applicable for uncovering the cellular pathways triggered by other extracellular stimuli.

Application of Adenosine Triphosphate Affinity Probe and Scheduled Multiple-Reaction Monitoring Analysis for Profiling Global Kinome in Human Cells in Response to Arsenite Treatment

PubMed Central

2015-01-01

Phosphorylation of cellular components catalyzed by kinases plays important roles in cell signaling and proliferation. Quantitative assessment of perturbation in global kinome may provide crucial knowledge for elucidating the mechanisms underlying the cytotoxic effects of environmental toxicants. Here, we utilized an adenosine triphosphate (ATP) affinity probe coupled with stable isotope labeling by amino acids in cell culture (SILAC) to assess quantitatively the arsenite-induced alteration of global kinome in human cells. We constructed a SILAC-compatible kinome library for scheduled multiple-reaction monitoring (MRM) analysis and adopted on-the-fly recalibration of retention time shift, which provided better throughput of the analytical method and enabled the simultaneous quantification of the expression of ∼300 kinases in two LC-MRM runs. With this improved analytical method, we conducted an in-depth quantitative analysis of the perturbation of kinome of GM00637 human skin fibroblast cells induced by arsenite exposure. Several kinases involved in cell cycle progression, including cyclin-dependent kinases (CDK1 and CDK4) and Aurora kinases A, B, and C, were found to be hyperactivated, and the altered expression of CDK1 was further validated by Western analysis. In addition, treatment with a CDK inhibitor, flavopiridol, partially restored the arsenite-induced growth inhibition of human skin fibroblast cells. Thus, sodium arsenite may confer its cytotoxic effect partly through the aberrant activation of CDKs and the resultant perturbation of cell cycle progression. Together, we developed a high-throughput, SILAC-compatible, and MRM-based kinome profiling method and demonstrated that the method is powerful in deciphering the molecular modes of action of a widespread environmental toxicant. The method should be generally applicable for uncovering the cellular pathways triggered by other extracellular stimuli. PMID:25301106

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

PubMed

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

2016-02-11

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

Extractive Atmospheric Pressure Photoionization (EAPPI) Mass Spectrometry: Rapid Analysis of Chemicals in Complex Matrices.

PubMed

Liu, Chengyuan; Yang, Jiuzhong; Wang, Jian; Hu, Yonghua; Zhao, Wan; Zhou, Zhongyue; Qi, Fei; Pan, Yang

2016-10-01

Extractive atmospheric pressure photoionization (EAPPI) mass spectrometry was designed for rapid qualitative and quantitative analysis of chemicals in complex matrices. In this method, an ultrasonic nebulization system was applied to sample extraction, nebulization, and vaporization. Mixed with a gaseous dopant, vaporized analytes were ionized through ambient photon-induced ion-molecule reactions, and were mass-analyzed by a high resolution time-of-flight mass spectrometer (TOF-MS). After careful optimization and testing with pure sample solution, EAPPI was successfully applied to the fast screening of capsules, soil, natural products, and viscous compounds. Analysis was completed within a few seconds without the need for preseparation. Moreover, the quantification capability of EAPPI for matrices was evaluated by analyzing six polycyclic aromatic hydrocarbons (PAHs) in soil. The correlation coefficients (R (2) ) for standard curves of all six PAHs were above 0.99, and the detection limits were in the range of 0.16-0.34 ng/mg. In addition, EAPPI could also be used to monitor organic chemical reactions in real time. Graphical Abstract ᅟ.

Ethylene monitoring and control system

NASA Technical Reports Server (NTRS)

Nelson, Bruce N. (Inventor); Kanc, James A. (Inventor); Richard, II, Roy V. (Inventor)

2000-01-01

A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

Ethylene monitoring and control system

NASA Technical Reports Server (NTRS)

Nelson, Bruce N. (Inventor); Kane, James A. (Inventor); Richard, II, Roy V. (Inventor)

2001-01-01

A system that can accurately monitor and control low concentrations of ethylene gas includes a test chamber configured to receive sample gas potentially containing an ethylene concentration and ozone, a detector configured to receive light produced during a reaction between the ethylene and ozone and to produce signals related thereto, and a computer connected to the detector to process the signals to determine therefrom a value of the concentration of ethylene in the sample gas. The supply for the system can include a four way valve configured to receive pressurized gas at one input and a test chamber. A piston is journaled in the test chamber with a drive end disposed in a drive chamber and a reaction end defining with walls of the test chamber a variable volume reaction chamber. The drive end of the piston is pneumatically connected to two ports of the four way valve to provide motive force to the piston. A manifold is connected to the variable volume reaction chamber, and is configured to receive sample gasses from at least one of a plurality of ports connectable to degreening rooms and to supply the sample gas to the reactive chamber for reaction with ozone. The apparatus can be used to monitor and control the ethylene concentration in multiple degreening rooms.

Use of Sensitive and Specific Biomolecular and Mass Spectrometric Techniques to Monitor the Performance of In-Situ Hydrocarbon Biodegradation

NASA Astrophysics Data System (ADS)

Beller, H. R.; Kane, S. R.; Legler, T. C.

2008-12-01

Monitored natural attenuation (MNA) can be a cost-effective and viable approach for remediation of hydrocarbon-contaminated groundwater. However, regulatory acceptance of the approach is often contingent on monitoring that can convincingly demonstrate the role of microbial degradation. Recent advances in anaerobic hydrocarbon biochemistry, analytical chemistry, and molecular biology have fostered the development of powerful techniques that can be applied to MNA of BTEX (benzene, toluene, ethylbenzene, and xylenes). Here, I discuss two independent methods that have been developed to monitor in situ, anaerobic biodegradation of toluene and xylenes. A method has been developed for rapid, sensitive, and highly selective detection of distinctive indicators of anaerobic alkylbenzene metabolism. The target metabolites, benzylsuccinic acid and methylbenzylsuccinic acid isomers, have no known sources other than anaerobic toluene or xylene degradation; thus, their mere presence in groundwater provides definitive evidence of in situ metabolism. The method, which involves small sample size (<1 mL) and no extraction/concentration steps, relies on isotope dilution liquid chromatography/tandem mass spectrometry (LC/MS/MS) with selected reaction monitoring. Detection limits for benzylsuccinates were determined to be ca. 0.3 μg/L and accuracy and precision were favorable in a groundwater matrix. A monitoring method based on quantitative Polymerase Chain Reaction (qPCR) analysis has been developed to specifically quantify populations of anaerobic methylbenzene-degrading bacteria in aquifer sediment. The method targets a catabolic gene (bssA) associated with the first step of anaerobic toluene and xylene degradation. The method has proven to be sensitive (detection limit ca. 5 gene copies) and has a linear range of > 7 orders of magnitude. Application of these two methods in field studies will be discussed in the context of the methods' strengths and limitations. Field data will include a side-by-side comparison of the two methods during a controlled release of BTX and ethanol, simulating release of gasohol from a leaking underground storage tank.

Oxygen Mass Flow Rate Generated for Monitoring Hydrogen Peroxide Stability

NASA Technical Reports Server (NTRS)

Ross, H. Richard

2002-01-01

Recent interest in propellants with non-toxic reaction products has led to a resurgence of interest in hydrogen peroxide for various propellant applications. Because peroxide is sensitive to contaminants, material interactions, stability and storage issues, monitoring decomposition rates is important. Stennis Space Center (SSC) uses thermocouples to monitor bulk fluid temperature (heat evolution) to determine reaction rates. Unfortunately, large temperature rises are required to offset the heat lost into the surrounding fluid. Also, tank penetration to accomodate a thermocouple can entail modification of a tank or line and act as a source of contamination. The paper evaluates a method for monitoring oxygen evolution as a means to determine peroxide stability. Oxygen generation is not only directly related to peroxide decomposition, but occurs immediately. Measuring peroxide temperature to monitor peroxide stability has significant limitations. The bulk decomposition of 1% / week in a large volume tank can produce in excess of 30 cc / min. This oxygen flow rate corresponds to an equivalent temperature rise of approximately 14 millidegrees C, which is difficult to measure reliably. Thus, if heat transfer were included, there would be no temperature rise. Temperature changes from the surrounding environment and heat lost to the peroxide will also mask potential problems. The use of oxygen flow measurements provides an ultra sensitive technique for monitoring reaction events and will provide an earlier indication of an abnormal decomposition when compared to measuring temperature rise.

CHROMATOGRAPHIC SEPARATION AND IDENTIFICATION OF PRODUCTS FROM THE REACTION OF DIMETHYLARSINIC ACID WITH HYDROGEN SULFIDE

EPA Science Inventory

The reaction of dimethylarsinic acid (DMAV) with hydrogen sulfide (H2S) is of biological significance and may be implicated in the overall toxicity and carcinogenicity of arsenic. The course of the reaction in aqueous phase was monitored and an initial product, dimethylthioarsin...

Online monitoring of a photocatalytic reaction by real-time high resolution FlowNMR spectroscopy.

PubMed

Hall, Andrew M R; Broomfield-Tagg, Rachael; Camilleri, Matthew; Carbery, David R; Codina, Anna; Whittaker, David T E; Coombes, Steven; Lowe, John P; Hintermair, Ulrich

2017-12-19

We demonstrate how FlowNMR spectroscopy can readily be applied to investigate photochemical reactions that require sustained input of light and air to yield mechanistic insight under realistic conditions. The Eosin Y mediated photo-oxidation of N-allylbenzylamine is shown to produce imines as primary reaction products from which undesired aldehydes form after longer reaction times. Facile variation of reaction conditions during the reaction in flow allows for probe experiments that give information about the mode of action of the photocatalyst.

Automated detection of inaccurate and imprecise transitions in peptide quantification by multiple reaction monitoring mass spectrometry.

PubMed

Abbatiello, Susan E; Mani, D R; Keshishian, Hasmik; Carr, Steven A

2010-02-01

Multiple reaction monitoring mass spectrometry (MRM-MS) of peptides with stable isotope-labeled internal standards (SISs) is increasingly being used to develop quantitative assays for proteins in complex biological matrices. These assays can be highly precise and quantitative, but the frequent occurrence of interferences requires that MRM-MS data be manually reviewed, a time-intensive process subject to human error. We developed an algorithm that identifies inaccurate transition data based on the presence of interfering signal or inconsistent recovery among replicate samples. The algorithm objectively evaluates MRM-MS data with 2 orthogonal approaches. First, it compares the relative product ion intensities of the analyte peptide to those of the SIS peptide and uses a t-test to determine if they are significantly different. A CV is then calculated from the ratio of the analyte peak area to the SIS peak area from the sample replicates. The algorithm identified problematic transitions and achieved accuracies of 94%-100%, with a sensitivity and specificity of 83%-100% for correct identification of errant transitions. The algorithm was robust when challenged with multiple types of interferences and problematic transitions. This algorithm for automated detection of inaccurate and imprecise transitions (AuDIT) in MRM-MS data reduces the time required for manual and subjective inspection of data, improves the overall accuracy of data analysis, and is easily implemented into the standard data-analysis work flow. AuDIT currently works with results exported from MRM-MS data-processing software packages and may be implemented as an analysis tool within such software.

Automated Detection of Inaccurate and Imprecise Transitions in Peptide Quantification by Multiple Reaction Monitoring Mass Spectrometry

PubMed Central

Abbatiello, Susan E.; Mani, D. R.; Keshishian, Hasmik; Carr, Steven A.

2010-01-01

BACKGROUND Multiple reaction monitoring mass spectrometry (MRM-MS) of peptides with stable isotope–labeled internal standards (SISs) is increasingly being used to develop quantitative assays for proteins in complex biological matrices. These assays can be highly precise and quantitative, but the frequent occurrence of interferences requires that MRM-MS data be manually reviewed, a time-intensive process subject to human error. We developed an algorithm that identifies inaccurate transition data based on the presence of interfering signal or inconsistent recovery among replicate samples. METHODS The algorithm objectively evaluates MRM-MS data with 2 orthogonal approaches. First, it compares the relative product ion intensities of the analyte peptide to those of the SIS peptide and uses a t-test to determine if they are significantly different. A CV is then calculated from the ratio of the analyte peak area to the SIS peak area from the sample replicates. RESULTS The algorithm identified problematic transitions and achieved accuracies of 94%–100%, with a sensitivity and specificity of 83%–100% for correct identification of errant transitions. The algorithm was robust when challenged with multiple types of interferences and problematic transitions. CONCLUSIONS This algorithm for automated detection of inaccurate and imprecise transitions (AuDIT) in MRM-MS data reduces the time required for manual and subjective inspection of data, improves the overall accuracy of data analysis, and is easily implemented into the standard data-analysis work flow. AuDIT currently works with results exported from MRM-MS data-processing software packages and may be implemented as an analysis tool within such software. PMID:20022980

Characterization of solution-phase and gas-phase reactions in on-line electrochemistry-thermospray tandem mass spectrometry.

PubMed

Volk, K J; Yost, R A; Brajter-Toth, A

1989-07-14

Electrochemistry was used on-line with high-performance liquid chromatography-thermospray tandem mass spectrometry to provide insight into the solution-phase decomposition reactions of electrochemically generated oxidation products. Products formed during electrooxidation were monitored as the electrode potential was varied. The solution reactions which follow the initial electron transfer at the electrode are affected by the vaporizer tip temperature of the thermospray probe and the composition of the thermospray buffer. Either hydrolysis or ammonolysis reactions of the initial electrochemical oxidation products can occur with pH 7 ammonium acetate buffer. Both the electrochemically generated and the synthesized disulfide of 6-thiopurine decompose under thermospray conditions to produce 6-thiopurine and purine-6-sulfinate. Solution-phase studies indicate that nucleophilic and electrophilic substitution reactions with purine-6-sulfinate result in the formation of purine, adenine, and hypoxanthine. Products were identified and characterized by tandem mass spectrometry. This work shows the first example of high-performance liquid chromatography used on-line with electrochemistry to separate stable oxidation products prior to analysis by thermospray tandem mass spectrometry. In addition, solution-phase and gas-phase studies with methylamine show that the site of the nucleophilic and electrophilic reactions is probably inside the thermospray probe. Most importantly, these results also show that the on-line combination of electrochemistry with thermospray tandem mass spectrometry provides valuable information about redox and associated chemical reactions of biological molecules such as the structures of intermediates or products as well as providing insight into reaction pathways.

Fusion of microlitre water-in-oil droplets for simple, fast and green chemical assays.

PubMed

Chiu, S-H; Urban, P L

2015-08-07

A simple format for microscale chemical assays is proposed. It does not require the use of test tubes, microchips or microtiter plates. Microlitre-range (ca. 0.7-5.0 μL) aqueous droplets are generated by a commercial micropipette in a non-polar matrix inside a Petri dish. When two droplets are pipetted nearby, they spontaneously coalesce within seconds, priming a chemical reaction. Detection of the reaction product is accomplished by colorimetry, spectrophotometry, or fluorimetry using simple light-emitting diode (LED) arrays as the sources of monochromatic light, while chemiluminescence detection of the analytes present in single droplets is conducted in the dark. A smartphone camera is used as the detector. The limits of detection obtained for the developed in-droplet assays are estimated to be: 1.4 nmol (potassium permanganate by colorimetry), 1.4 pmol (fluorescein by fluorimetry), and 580 fmol (sodium hypochlorite by chemiluminescence detection). The format has successfully been used to monitor the progress of chemical and biochemical reactions over time with sub-second resolution. A semi-quantitative analysis of ascorbic acid using Tillman's reagent is presented. A few tens of individual droplets can be scanned in parallel. Rapid switching of the LED light sources with different wavelengths enables a spectral analysis of multiple droplets. Very little solid waste is produced. The assay matrix is readily recycled, thus the volume of liquid waste produced each time is also very small (typically, 1-10 μL per analysis). Various water-immiscible translucent liquids can be used as the reaction matrix: including silicone oil, 1-octanol as well as soybean cooking oil.

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

PubMed

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.

[Methods Used for Monitoring Cure Reactions in Real-time in an Autoclave

NASA Technical Reports Server (NTRS)

Cooper, John B.; Wise, Kent L.; Jensen, Brian J. (Technical Monitor)

2000-01-01

The goal of the research was to investigate methods for monitoring cure reactions in real-time in an autoclave. This is of particular importance to NASA Langley Research Center because polyimides were proposed for use in the High Speed Civil Transport (HSCT) program. Understanding the cure chemistry behind the polyimides would allow for intelligent processing of the composites made from their use. This work has led to two publications in peer-reviewed journals and a patent. The journal articles are listed as Appendix A which is on the instrument design of the research and Appendix B which is on the cure chemistry. Also, a patent has been awarded for the instrumental design developed under this grant which is given as Appendix C. There has been a significant amount of research directed at developing methods for monitoring cure reactions in real-time within the autoclave. The various research efforts can be categorized as methods providing either direct chemical bonding information or methods that provide indirect chemical bonding information. Methods falling into the latter category are fluorescence, dielectric loss, ultrasonic and similar type methods. Correlation of such measurements with the underlying chemistry is often quite difficult since these techniques do not allow monitoring of the curing chemistry which is ultimately responsible for material properties. Direct methods such as vibrational spectroscopy, however, can often be easily correlated with the underlying chemistry of a reaction. Such methods include Raman spectroscopy, mid-IR absorbance, and near-IR absorbance. With the recent advances in fiber-optics, these spectroscopic techniques can be applied to remote on-line monitoring.

Immobilized Metal Affinity Chromatography Coupled to Multiple Reaction Monitoring Enables Reproducible Quantification of Phospho-signaling*

PubMed Central

Kennedy, Jacob J.; Yan, Ping; Zhao, Lei; Ivey, Richard G.; Voytovich, Uliana J.; Moore, Heather D.; Lin, Chenwei; Pogosova-Agadjanyan, Era L.; Stirewalt, Derek L.; Reding, Kerryn W.; Whiteaker, Jeffrey R.; Paulovich, Amanda G.

2016-01-01

A major goal in cell signaling research is the quantification of phosphorylation pharmacodynamics following perturbations. Traditional methods of studying cellular phospho-signaling measure one analyte at a time with poor standardization, rendering them inadequate for interrogating network biology and contributing to the irreproducibility of preclinical research. In this study, we test the feasibility of circumventing these issues by coupling immobilized metal affinity chromatography (IMAC)-based enrichment of phosphopeptides with targeted, multiple reaction monitoring (MRM) mass spectrometry to achieve precise, specific, standardized, multiplex quantification of phospho-signaling responses. A multiplex immobilized metal affinity chromatography- multiple reaction monitoring assay targeting phospho-analytes responsive to DNA damage was configured, analytically characterized, and deployed to generate phospho-pharmacodynamic curves from primary and immortalized human cells experiencing genotoxic stress. The multiplexed assays demonstrated linear ranges of ≥3 orders of magnitude, median lower limit of quantification of 0.64 fmol on column, median intra-assay variability of 9.3%, median inter-assay variability of 12.7%, and median total CV of 16.0%. The multiplex immobilized metal affinity chromatography- multiple reaction monitoring assay enabled robust quantification of 107 DNA damage-responsive phosphosites from human cells following DNA damage. The assays have been made publicly available as a resource to the community. The approach is generally applicable, enabling wide interrogation of signaling networks. PMID:26621847

Single-molecule enzymology based on the principle of the Millikan oil drop experiment.

PubMed

Leiske, Danielle L; Chow, Andrea; Dettloff, Roger; Farinas, Javier

2014-03-01

The ability to monitor the progress of single-molecule enzyme reactions is often limited by the need to use fluorogenic substrates. A method based on the principle of the Millikan oil drop experiment was developed to monitor the change in charge of substrates bound to a nanoparticle and offers a means of detecting single-enzyme reactions without fluorescence detection. As a proof of principle of the ability to monitor reactions that result in a change in substrate charge, polymerization on a single DNA template was detected. A custom oligonucleotide was synthesized that allowed for the attachment of single DNA templates to gold nanoparticles with a single polymer tether. The nanoparticles were then tethered to the surface of a microfluidic channel where the positions of the nanoparticles, subjected to an oscillating electric field, were monitored using dark field microscopy. With short averaging times, the signal-to-noise level was low enough to discriminate changes in charge of less than 1.2%. Polymerization of a long DNA template demonstrated the ability to use the system to monitor single-molecule enzymatic activity. Finally, nanoparticle surfaces were modified with thiolated moieties to reduce and/or shield the number of unproductive charges and allow for improved sensitivity. Copyright © 2013 Elsevier Inc. All rights reserved.

Single-Molecule Enzymology Based On The Principle Of The Millikan Oil Drop Experiment

PubMed Central

Leiske, Danielle L.; Chow, Andrea; Dettloff, Roger; Farinas, Javier

2014-01-01

The ability to monitor the progress of single molecule enzyme reactions is often limited by the need to use fluorogenic substrates. A method based on the principle of the Millikan Oil Drop Experiment was developed to monitor the change in charge of substrates bound to a nanoparticle and offers a means of detecting single enzyme reactions without fluorescence detection. As a proof of principle of the ability to monitor reactions which result in a change in substrate charge, polymerization on a single DNA template was detected. A custom oligonucleotide was synthesized which allowed for the attachment of single DNA templates to gold nanoparticles with a single polymer tether. The nanoparticles were then tethered to the surface of a microfluidic channel where the positions of the nanoparticles, subjected to an oscillating electric field, were monitored using darkfield microscopy. With short averaging times, the signal-to-noise level was low enough to discriminate changes in charge of less than 1.2%. Polymerization of a long DNA template demonstrated the ability to use the system to monitor single molecule enzymatic activity. Finally, nanoparticle surfaces were modified with thiolated moieties in order to reduce and/or shield the number of unproductive charges and allow for improved sensitivity. PMID:24291542

Genetic Fingerprinting Using Microsatellite Markers in a Multiplex PCR Reaction: A Compilation of Methodological Approaches from Primer Design to Detection Systems.

PubMed

Krüger, Jacqueline; Schleinitz, Dorit

2017-01-01

Microsatellites are polymorphic DNA loci comprising repeated sequence motifs of two to five base pairs which are dispersed throughout the genome. Genotyping of microsatellites is a widely accepted tool for diagnostic and research purposes such as forensic investigations and parentage testing, but also in clinics (e.g. monitoring of bone marrow transplantation), as well as for the agriculture and food industries. The co-amplification of several short tandem repeat (STR) systems in a multiplex reaction with simultaneous detection helps to obtain more information from a DNA sample where its availability may be limited. Here, we introduce and describe this commonly used genotyping technique, providing an overview on available resources on STRs, multiplex design, and analysis.

High-throughput syntheses of iron phosphite open frameworks in ionic liquids

NASA Astrophysics Data System (ADS)

Wang, Zhixiu; Mu, Ying; Wang, Yilin; Bing, Qiming; Su, Tan; Liu, Jingyao

2017-02-01

Three open-framework iron phosphites: Feп5(NH4)2(HPO3)6 (1), Feп2Fe♯(NH4)(HPO3)4 (2) and Fe♯2(HPO3)3 (3) have been synthesized under ionothermal conditions. How the different synthesis parameters, such as the gel concentrations, synthetic times, reaction temperatures and solvents affect the products have been monitored by using high-throughput approaches. Within each type of experiment, relevant products have been investigated. The optimal reaction conditions are obtained from a series of experiments by high-throughput approaches. All the structures are determined by single-crystal X-ray diffraction analysis and further characterized by PXRD, TGA and FTIR analyses. Magnetic study reveals that those three compounds show interesting magnetic behavior at low temperature.

A self optimizing synthetic organic reactor system using real-time in-line NMR spectroscopy† †Electronic supplementary information (ESI) available: Details about the methodology, LabView scripts, experimental set-ups, additional spectra and self-optimization can be found in the SI. See DOI: 10.1039/c4sc03075c Click here for additional data file.

PubMed Central

Sans, Victor; Porwol, Luzian; Dragone, Vincenza

2015-01-01

A configurable platform for synthetic chemistry incorporating an in-line benchtop NMR that is capable of monitoring and controlling organic reactions in real-time is presented. The platform is controlled via a modular LabView software control system for the hardware, NMR, data analysis and feedback optimization. Using this platform we report the real-time advanced structural characterization of reaction mixtures, including 19F, 13C, DEPT, 2D NMR spectroscopy (COSY, HSQC and 19F-COSY) for the first time. Finally, the potential of this technique is demonstrated through the optimization of a catalytic organic reaction in real-time, showing its applicability to self-optimizing systems using criteria such as stereoselectivity, multi-nuclear measurements or 2D correlations. PMID:29560211

Integrated active mixing and biosensing using low frequency vibrating mixer and Love-wave sensor for real time detection of antibody binding event

NASA Astrophysics Data System (ADS)

Kardous, F.; El Fissi, L.; Friedt, J.-M.; Bastien, F.; Boireau, W.; Yahiaoui, R.; Manceau, J.-F.; Ballandras, S.

2011-05-01

The development of lab-on-chip devices is expected to dramatically change biochemical analyses, allowing for a notable increase of processing quality and throughput, provided the induced chemical reactions are well controlled. In this work, we investigate the impact of local acoustic mixing to promote or accelerate such biochemical reactions, such as antibody grafting on activated surfaces. During microarray building, the spotting mode leads to low efficiency in the ligand grafting and heterogeneities which limits its performances. To improve the transfer rate, we induce a hydrodynamic flow in the spotted droplet to disrupt the steady state during antibody grafting. To prove that acoustic mixing increases the antibody transfer rate to the biochip surface, we have used a Love-wave sensor allowing for real-time monitoring of the biological reaction for different operating conditions (with or without mixing). An analysis of the impact of the proposed mixing on grafting kinetics is proposed and finally checked in the case of antibody-antigen combination.

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

PubMed

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.

Biodiesel transesterification kinetics monitored by pH measurement.

PubMed

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.

Real-time monitoring of enzyme-free strand displacement cascades by colorimetric assays

NASA Astrophysics Data System (ADS)

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

In situ monitoring of atomic layer controlled pore reduction in alumina tubular membranes using sequential surface reactions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Berland, B.S.; Gartland, I.P.; Ott, A.W.

1998-12-01

The pore diameter in alumina tubular membranes with an initial diameter of 50 {angstrom} was systematically reduced using the atomic layer controlled deposition of Al{sub 2}O{sub 3}. The Al{sub 2}O{sub 3} was deposited using sequential exposures of Al(CH{sub 3}){sub 3} (trimethylaluminum, TMA) and H{sub 2}O in an ABAB... binary reaction sequence. The pore diameter reduction was monitored using in situ N{sub 2} and Ar conductance measurements. The conductance, C = Q/{Delta}P, was measured using a mass flow controller to define a constant gas throughput, Q, and a pair of capacitance manometers to monitor the transmembrane pressure drop, {Delta}P. Conductance measurementsmore » were periodically obtained at 298 K as a function of AB binary reaction cycles. These conductance measurements were consistent with a pore diameter reduction from 50 {angstrom} to {approximately}5--10 {angstrom} at a rate of {approximately}2.5 {angstrom} for each AB cycle. Conductance measurements were also performed during the Al{sub 2}O{sub 3} deposition at 500 K after each half-reaction in the binary reaction sequence. These in situ conductance measurements demonstrate that the pore diameters in mesoporous membranes can be reduced to molecular dimensions with atomic layer control using sequential surface reactions. Poe diameters can be tailored for specific applications by varying the number of AB cycles and changing the nature of the terminating surface functional groups.« less

Adverse reactions to contrast media: an analysis of spontaneous reports in the database of the pharmacovigilance programme of India.

PubMed

Kalaiselvan, Vivekanandan; Sharma, Surbhi; Singh, Gyanendra Nath

2014-09-01

Contrast media are used widely to improve medical imaging. Like all other pharmaceuticals, these agents are not completely devoid of risk, and continuous monitoring of adverse reactions with these agents is important. Spontaneous reporting is the simplest method for understanding the safety profile of pharmaceutical products after their approval. Our objective was to identify the pattern and characteristics of adverse reactions attributed to contrast media in the Indian population reported to the National Coordination Centre for the Pharmacovigilance Programme of India (NCC-PvPI). Individual case safety reports (ICSRs) attributed to contrast media submitted spontaneously to the NCC-PvPI were extracted from the database for July 2010 to September 2013. We analysed these reports for information related to reporter's professional category, patient's age and sex, reporter's diagnosis of the reaction, seriousness of the reaction, type of contrast media exposure, system organ class (SOC) affected (as described in World Health Organization Adverse Reaction Terminology [WHO-ART]) and outcome. Of the total 59,915 ICSRs in the database, 415 (0.7%) were suspected adverse reactions to contrast media; 44 reports were serious, including three fatal cases. The most affected SOCs were skin and appendage disorders, body as a whole-general disorders, gastrointestinal system disorders and respiratory system disorders. Hypersensitivity reactions were reported in the majority of ICSRs. The contrast media with the highest number of reports were iohexol (40.7%), iomeprol (17.8%), iopamidol (12%) and diatrizoate (12%). Most of the reactions to contrast media were allergic-like, and no previously unrecognised adverse reactions were observed in the Indian population. Further data and increased awareness among healthcare professionals is required to signal and prevent the consequences of adverse reactions attributed to contrast media.

Pollution monitoring system. [photographic laboratory by-products

NASA Technical Reports Server (NTRS)

Goodding, R. A.

1973-01-01

An investigation was undertaken to identify those photographic laboratory by-products which can produce harmful reactions if released untreated. After identification of these by-products, specific monitoring systems for each of the offending ions were investigated and recommendations for implementation are presented. Appropriate monitoring systems are discussed.

The life sciences mass spectrometry research unit.

PubMed

Hopfgartner, Gérard; Varesio, Emmanuel

2012-01-01

The Life Sciences Mass Spectrometry (LSMS) research unit focuses on the development of novel analytical workflows based on innovative mass spectrometric and software tools for the analysis of low molecular weight compounds, peptides and proteins in complex biological matrices. The present article summarizes some of the recent work of the unit: i) the application of matrix-assisted laser desorption/ionization (MALDI) for mass spectrometry imaging (MSI) of drug of abuse in hair, ii) the use of high resolution mass spectrometry for simultaneous qualitative/quantitative analysis in drug metabolism and metabolomics, and iii) the absolute quantitation of proteins by mass spectrometry using the selected reaction monitoring mode.

Recent Advances in Clinical Glycoproteomics of Immunoglobulins (Igs).

PubMed

Plomp, Rosina; Bondt, Albert; de Haan, Noortje; Rombouts, Yoann; Wuhrer, Manfred

2016-07-01

Antibody glycosylation analysis has seen methodological progress resulting in new findings with regard to antibody glycan structure and function in recent years. For example, antigen-specific IgG glycosylation analysis is now applicable for clinical samples because of the increased sensitivity of measurements, and this has led to new insights in the relationship between IgG glycosylation and various diseases. Furthermore, many new methods have been developed for the purification and analysis of IgG Fc glycopeptides, notably multiple reaction monitoring for high-throughput quantitative glycosylation analysis. In addition, new protocols for IgG Fab glycosylation analysis were established revealing autoimmune disease-associated changes. Functional analysis has shown that glycosylation of IgA and IgE is involved in transport across the intestinal epithelium and receptor binding, respectively. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Real-time monitoring of enzyme-free strand displacement cascades by colorimetric assays.

PubMed

Duan, Ruixue; Wang, Boya; Hong, Fan; Zhang, Tianchi; Jia, Yongmei; Huang, Jiayu; Hakeem, Abdul; Liu, Nannan; Lou, Xiaoding; Xia, Fan

2015-03-19

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.

Comprehensive near infrared study of Jatropha oil esterification with ethanol for biodiesel production

NASA Astrophysics Data System (ADS)

Oliveira, Alianda Dantas de; Sá, Ananda Franco de; Pimentel, Maria Fernanda; Pacheco, José Geraldo A.; Pereira, Claudete Fernandes; Larrechi, Maria Soledad

2017-01-01

This work presents a comprehensive near infrared study for in-line monitoring of the esterification reaction of high acid oils, such as Jatropha curcas oil, using ethanol. Parallel reactions involved in the process were carried out to select a spectral region that characterizes the evolution of the esterification reaction. Using absorbance intensities at 5176 cm- 1, the conversion and kinetic behaviors of the esterification reaction were estimated. This method was applied to evaluate the influence of temperature and catalyst concentration on the estimates of initial reaction rate and ester conversion as responses to a 22 factorial experimental design. Employment of an alcohol/oil ratio of 16:1, catalyst concentration of 1.5% w/w, and temperatures at 65 °C or 75 °C, made it possible to reduce the initial acidity from 18% to 1.3% w/w, which is suitable for transesterification of high free fatty acid oils for biodiesel production. Using the proposed analytical method in the esterification reaction of raw materials with high free fatty acid content for biodiesel makes the monitoring process inexpensive, fast, simple, and practical.

Development of a liquid chromatography-multiple reaction monitoring procedure for concurrent verification of exposure to different forms of mustard agents.

PubMed

Yeo, Thong-Hiang; Ho, Mer-Lin; Loke, Weng-Keong

2008-01-01

A novel liquid chromatography-multiple reaction monitoring (LC-MRM) procedure has been developed for retrospective diagnosis of exposure to different forms of mustard agents. This concise method is able to validate prior exposure to nitrogen mustards (HN-1, HN-2, and HN-3) or sulfur mustard (HD) in a single run, which significantly reduces analysis time compared to separate runs to screen for different mustards' biomarkers based on tandem mass spectrometry. Belonging to one of the more toxic classes of chemical warfare agents, these potent vesicants bind covalently to the cysteine-34 residue of human serum albumin. This results in the formation of stable adducts whose identities were confirmed by a de novo sequencing bioinformatics software package. Our developed technique tracks these albumin-derived adduct biomarkers in blood samples which persist in vitro following exposure, enabling a detection limit of 200 nM of HN-1, 100 nM of HN-2, 200 nM of HN-3, or 50 nM of HD in human blood. The CWA-adducts formed in blood samples can be conveniently and sensitively analyzed by this MRM technique to allow rapid and reliable screening.

Biomarker Development for Intraductal Papillary Mucinous Neoplasms Using Multiple Reaction Monitoring Mass Spectrometry.

PubMed

Kim, Yikwon; Kang, MeeJoo; Han, Dohyun; Kim, Hyunsoo; Lee, KyoungBun; Kim, Sun-Whe; Kim, Yongkang; Park, Taesung; Jang, Jin-Young; Kim, Youngsoo

2016-01-04

Intraductal papillary mucinous neoplasm (IPMN) is a common precursor of pancreatic cancer (PC). Much clinical attention has been directed toward IPMNs due to the increase in the prevalence of PC. The diagnosis of IPMN depends primarily on a radiological examination, but the diagnostic accuracy of this tool is not satisfactory, necessitating the development of accurate diagnostic biomarkers for IPMN to prevent PC. Recently, high-throughput targeted proteomic quantification methods have accelerated the discovery of biomarkers, rendering them powerful platforms for the evolution of IPMN diagnostic biomarkers. In this study, a robust multiple reaction monitoring (MRM) pipeline was applied to discovery and verify IPMN biomarker candidates in a large cohort of plasma samples. Through highly reproducible MRM assays and a stringent statistical analysis, 11 proteins were selected as IPMN marker candidates with high confidence in 184 plasma samples, comprising a training (n = 84) and test set (n = 100). To improve the discriminatory power, we constructed a six-protein panel by combining marker candidates. The multimarker panel had high discriminatory power in distinguishing between IPMN and controls, including other benign diseases. Consequently, the diagnostic accuracy of IPMN can be improved dramatically with this novel plasma-based panel in combination with a radiological examination.

A web-based quantitative signal detection system on adverse drug reaction in China.

PubMed

Li, Chanjuan; Xia, Jielai; Deng, Jianxiong; Chen, Wenge; Wang, Suzhen; Jiang, Jing; Chen, Guanquan

2009-07-01

To establish a web-based quantitative signal detection system for adverse drug reactions (ADRs) based on spontaneous reporting to the Guangdong province drug-monitoring database in China. Using Microsoft Visual Basic and Active Server Pages programming languages and SQL Server 2000, a web-based system with three software modules was programmed to perform data preparation and association detection, and to generate reports. Information component (IC), the internationally recognized measure of disproportionality for quantitative signal detection, was integrated into the system, and its capacity for signal detection was tested with ADR reports collected from 1 January 2002 to 30 June 2007 in Guangdong. A total of 2,496 associations including known signals were mined from the test database. Signals (e.g., cefradine-induced hematuria) were found early by using the IC analysis. In addition, 291 drug-ADR associations were alerted for the first time in the second quarter of 2007. The system can be used for the detection of significant associations from the Guangdong drug-monitoring database and could be an extremely useful adjunct to the expert assessment of very large numbers of spontaneously reported ADRs for the first time in China.

Oxidative damage in DNA bases revealed by UV resonant Raman spectroscopy.

PubMed

D'Amico, Francesco; Cammisuli, Francesca; Addobbati, Riccardo; Rizzardi, Clara; Gessini, Alessandro; Masciovecchio, Claudio; Rossi, Barbara; Pascolo, Lorella

2015-03-07

We report on the use of the UV Raman technique to monitor the oxidative damage of deoxynucleotide triphosphates (dATP, dGTP, dCTP and dTTP) and DNA (plasmid vector) solutions. Nucleotide and DNA aqueous solutions were exposed to hydrogen peroxide (H2O2) and iron containing carbon nanotubes (CNTs) to produce Fenton's reaction and induce oxidative damage. UV Raman spectroscopy is shown to be maximally efficient to reveal changes in the nitrogenous bases during the oxidative mechanisms occurring on these molecules. The analysis of Raman spectra, supported by numerical computations, revealed that the Fenton's reaction causes an oxidation of the nitrogenous bases in dATP, dGTP and dCTP solutions leading to the production of 2-hydroxyadenine, 8-hydroxyguanine and 5-hydroxycytosine. No thymine change was revealed in the dTTP solution under the same conditions. Compared to single nucleotide solutions, plasmid DNA oxidation has resulted in more radical damage that causes the breaking of the adenine and guanine aromatic rings. Our study demonstrates the advantage of using UV Raman spectroscopy for rapidly monitoring the oxidation changes in DNA aqueous solutions that can be assigned to specific nitrogenous bases.

Monitoring BTEX degradation by CSIA - chances and challenges

NASA Astrophysics Data System (ADS)

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 hydrogen isotope fractionation, the ratios of hydrogen vs. carbon isotope fractionation in two-dimensional plots (lambda values, Λ) were generally higher than 10 (in extreme cases > 100). Upon aerobic activation reactions at the aromatic ring catalyzed by mono- or dioxygenases, usually Λ values smaller than 10 were observed due to small, absent or inverse hydrogen isotope fractionation. An exception is the aerobic monooxygenation of methyl or methylene moieties which is linked to large hydrogen and carbon isotope fractionation. Since Λ values are highly indicative for specific transformation reactions, 2D-CSIA has a great potential for evaluating biodegradation processes of BTEX in the environment. Moreover, reactions catalyzed by benzylsuccinate synthases showed partially variable Λ values, indicating slightly different reaction mechanisms of isoenzymes, probably permitting the detection of specific isoenzymes by 2D-CSIA in field applications. In contrast, ethylbenzene dehydrogenase of three tested organisms showed similar, very characteristic isotope fractionation pattern even under different redox conditions. The major goal of future investigations is to use 2D-CSIA at contaminated field sites for elucidating specific degradation pathways. Single data for benzene are promising, demonstrating e.g., anaerobic benzene degradation by 2D-CSIA at a highly contaminated site. Nevertheless, 2D-CSIA field data for BTEX are yet lacking and need to be surveyed for a proper evaluation of the 2D-CSIA concept for BTEX.

Air-coupled ultrasound: a novel technique for monitoring the curing of thermosetting matrices.

PubMed

Lionetto, Francesca; Tarzia, Antonella; Maffezzoli, Alfonso

2007-07-01

A custom-made, air-coupled ultrasonic device was applied to cure monitoring of thick samples (7-10 mm) of unsaturated polyester resin at room temperature. A key point was the optimization of the experimental setup in order to propagate compression waves during the overall curing reaction by suitable placement of the noncontact transducers, placed on the same side of the test material, in the so-called pitch-catch configuration. The progress of polymerization was monitored through the variation of the time of flight of the propagating longitudinal waves. The exothermic character of the polymerization was taken into account by correcting the measured value of time of flight with that one in air, obtained by sampling the air velocity during the experiment. The air-coupled ultrasonic results were compared with those obtained from conventional contact ultrasonic measurements. The good agreement between the air-coupled ultrasonic results and those obtained by the rheological analysis demonstrated the reliability of air-coupled ultrasound in monitoring the changes of viscoelastic properties at gelation and vitrification. The position of the transducers on the same side of the sample makes this technique suitable for on-line cure monitoring during several composite manufacturing technologies.

Measurements of the thermal neutron cross-section and resonance integral for the 108Pd(n,γ)109Pd reaction

NASA Astrophysics Data System (ADS)

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.

Biological water quality monitoring using chemiluminescent and bioluminescent techniques

NASA Technical Reports Server (NTRS)

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.

Parallel Reaction Monitoring: A Targeted Experiment Performed Using High Resolution and High Mass Accuracy Mass Spectrometry

PubMed Central

Rauniyar, Navin

2015-01-01

The parallel reaction monitoring (PRM) assay has emerged as an alternative method of targeted quantification. The PRM assay is performed in a high resolution and high mass accuracy mode on a mass spectrometer. This review presents the features that make PRM a highly specific and selective method for targeted quantification using quadrupole-Orbitrap hybrid instruments. In addition, this review discusses the label-based and label-free methods of quantification that can be performed with the targeted approach. PMID:26633379

Safety and Efficacy of Ziagen (Abacavir Sulfate) in HIV-Infected Korean Patients.

PubMed

Ann, Heawon; Kim, Ki Hyon; Choi, Hyun Young; Chang, Hyun Ha; Han, Sang Hoon; Kim, Kye Hyung; Lee, Jin Soo; Kim, Yeon Sook; Park, Kyung Hwa; Kim, Young Keun; Sohn, Jang Wook; Yun, Na Ra; Lee, Chang Seop; Choi, Young Wha; Lee, Yil Seob; Kim, Shin Woo

2017-09-01

Abacavir is a widely-used nucleoside reverse transcriptase inhibitor for the treatment of human immunodeficiency virus (HIV) infection. Mandatory postmarketing surveillance was conducted in Korea to monitor the safety and evaluate the effectiveness of Ziagen® (abacavir sulfate 300 mg; ViiV Healthcare, Middlesex, UK). An open-label, multi-center, non-interventional postmarketing surveillance study was conducted from June 2010 to June 2016 to monitor the safety and effectiveness of Ziagen across 12 hospitals in Korea. Subjects older than 18 years taking Ziagen according to prescribing information were enrolled. The primary outcome was defined as the occurrence of any adverse events after Ziagen administration. Secondary outcomes included the occurrence of adverse drug reactions, occurrence of serious adverse events, and effectiveness of Ziagen administration. A total of 669 patients were enrolled in this study, with a total observation period of 1047.8 person-years. Of these, 90.7% of patients were male. The mean age of patients was 45.8±11.9 years. One-hundred ninety-six (29.3%) patients reported 315 adverse events, and four patients reported seven serious adverse events, without any fatal events. There was one potential case of an abacavir hypersensitivity reaction. Among the 97 adverse drug reactions that were reported from 75 patients, the most frequent adverse drug reactions included diarrhea (12 events), dyspepsia (10 events), and rash (9 events). No ischemic heart disease was observed. In the effectiveness analysis, 91% of patients achieved HIV-1 RNA under 50 copies/mL after 24 months of observation with abacavir administration. Our data showed the safety and effectiveness of Ziagen in a real-world setting. During the study period, Ziagen was well-tolerated, with one incident of a clinically suspected abacavir hypersensitivity reaction. The postmarketing surveillance of Ziagen did not highlight any new safety information. These data may be helpful in understanding abacavir and the HIV treatment practices in Korea. Copyright © 2017 by The Korean Society of Infectious Diseases and Korean Society for Chemotherapy

Monitoring Enzymatic Reactions in Real Time Using Venturi Easy Ambient Sonic-Spray Ionization Mass Spectrometry

PubMed Central

2016-01-01

We developed a technique to monitor spatially confined surface reactions with mass spectrometry under ambient conditions, without the need for voltage or organic solvents. Fused-silica capillaries immersed in an aqueous solution, positioned in close proximity to each other and the functionalized surface, created a laminar flow junction with a resulting reaction volume of ∼5 pL. The setup was operated with a syringe pump, delivering reagents to the surface through a fused-silica capillary. The other fused-silica capillary was connected to a Venturi easy ambient sonic-spray ionization source, sampling the resulting analytes at a slightly higher flow rate compared to the feeding capillary. The combined effects of the inflow and outflow maintains a chemical microenvironment, where the rate of advective transport overcomes diffusion. We show proof-of-concept where acetylcholinesterase was immobilized on an organosiloxane polymer through electrostatic interactions. The hydrolysis of acetylcholine by acetylcholinesterase into choline was monitored in real-time for a range of acetylcholine concentrations, fused-silica capillary geometries, and operating flow rates. Higher reaction rates and conversion yields were observed with increasing acetylcholine concentrations, as would be expected. PMID:27249533

Personnel reliability impact on petrochemical facilities monitoring system's failure skipping probability

NASA Astrophysics Data System (ADS)

Kostyukov, V. N.; Naumenko, A. P.

2017-08-01

The paper dwells upon urgent issues of evaluating impact of actions conducted by complex technological systems operators on their safe operation considering application of condition monitoring systems for elements and sub-systems of petrochemical production facilities. The main task for the research is to distinguish factors and criteria of monitoring system properties description, which would allow to evaluate impact of errors made by personnel on operation of real-time condition monitoring and diagnostic systems for machinery of petrochemical facilities, and find and objective criteria for monitoring system class, considering a human factor. On the basis of real-time condition monitoring concepts of sudden failure skipping risk, static and dynamic error, monitoring systems, one may solve a task of evaluation of impact that personnel's qualification has on monitoring system operation in terms of error in personnel or operators' actions while receiving information from monitoring systems and operating a technological system. Operator is considered as a part of the technological system. Although, personnel's behavior is usually a combination of the following parameters: input signal - information perceiving, reaction - decision making, response - decision implementing. Based on several researches on behavior of nuclear powers station operators in USA, Italy and other countries, as well as on researches conducted by Russian scientists, required data on operator's reliability were selected for analysis of operator's behavior at technological facilities diagnostics and monitoring systems. The calculations revealed that for the monitoring system selected as an example, the failure skipping risk for the set values of static (less than 0.01) and dynamic (less than 0.001) errors considering all related factors of data on reliability of information perception, decision-making, and reaction fulfilled is 0.037, in case when all the facilities and error probability are under control - not more than 0.027. In case when only pump and compressor units are under control, the failure skipping risk is not more than 0.022, when the probability of error in operator's action is not more than 0.011. The work output shows that on the basis of the researches results an assessment of operators' reliability can be made in terms of almost any kind of production, but considering only technological capabilities, since operators' psychological and general training considerable vary in different production industries. Using latest technologies of engineering psychology and design of data support systems, situation assessment systems, decision-making and responding system, as well as achievement in condition monitoring in various production industries one can evaluate hazardous condition skipping risk probability considering static, dynamic errors and human factor.

Synthesis, optimization and structural characterization of a chitosan-glucose derivative obtained by the Maillard reaction.

PubMed

Gullón, Beatriz; Montenegro, María I; Ruiz-Matute, Ana I; Cardelle-Cobas, Alejandra; Corzo, Nieves; Pintado, Manuela E

2016-02-10

Chitosan (Chit) was submitted to the Maillard reaction (MR) by co-heating a solution with glucose (Glc). Different reaction conditions as temperature (40, 60 and 80 °C), Glc concentration (0.5%, 1%, and 2%, w/v), and reaction time (72, 52 and 24h) were evaluated. Assessment of the reaction extent was monitored by measuring changes in UV absorbance, browning and fluorescence. Under the best conditions, 2% (w/v) of Chit, 2% (w/v) of Glc at 60°C and 32 h of reaction time, a chitosan-glucose (Chit-Glc) derivative was purified and submitted to structural characterization to confirm its formation. Analysis of its molecular weight (MW) and the degree of substitution (DS) was carried out by HPLC-Size Exclusion Chromatography (SEC) and a colloid titration method, respectively. FT-IR and (1)H NMR were also used to analyze the functional groups and evaluate the introduction of Glc into the Chit molecule. According to our objectives, the results obtained in this work allowed to better understand the key parameters influencing the MR with Chit as well as to confirm the successful introduction of Glc into the Chit molecule obtaining a Chit-Glc derivative with a DS of 64.76 ± 4.40% and a MW of 210.37 kDa. Copyright © 2015 Elsevier Ltd. All rights reserved.

Kinetic spectrophotometric method for determination of amlodipine besylate in its pharmaceutical tablets

PubMed Central

Mahmoud, Ashraf M.; Abdel-Wadood, Hanaa M.; Mohamed, Niveen A.

2012-01-01

A simple and sensitive kinetic spectrophotometric method has been developed and validated for determination of amlodipine besylate (AML). The method was based on the condensation reaction of AML with 7-chloro-4-nitro-2,1,3-benzoxadiazole in an alkaline buffer (pH 8.6) producing a highly colored product. The color development was monitored spectrophometrically at the maximum absorption λmax 470 nm. The factors affecting the reaction were studied and the conditions were optimized. The stoichiometry of the reaction was determined, and the reaction pathway was postulated. Moreover, both the activation energy and the specific rate constant (at 70 °C) of the reaction were found to be 6.74 kcal mole−1 and 3.58 s−1, respectively. The initial rate and fixed time methods were utilized for constructing the calibration graphs for the determination of AML concentration. Under the optimum reaction conditions, the limits of detection and quantification were 0.35 and 1.05 μg/mL, respectively. The precision of the method was satisfactory; the relative standard deviations were 0.85–1.76%. The proposed method was successfully applied to the analysis of AML in its pure form and tablets with good accuracy; the recovery percentages ranged from 99.55±1.69% to 100.65±1.48%. The results were compared with that of the reported method. PMID:29403763

Serial measurement of serum cytokines, cytokine receptors and neopterin in leprosy patients with reversal reactions.

PubMed

Faber, W R; Iyer, A M; Fajardo, T T; Dekker, T; Villahermosa, L G; Abalos, R M; Das, P K

2004-09-01

Serum levels of cytokines (IL-4, IL-5, IFN-gamma, TNF-alpha), cytokine receptors (TNFR I and II) and one monokine (neopterin) were estimated in seven leprosy patients to establish disease associated markers for reversal reactions (RR). Sera were collected at diagnosis of leprosy, at the onset of reversal reaction and at different time points during and at the end of prednisone treatment of reactions. It was expected that the serum cytokine and monokine profile before and at different time points during reactions would provide guidelines for the diagnosis and monitoring of reversal reactions in leprosy. The cytokines and cytokine receptors were measured by ELISA, whereas a radioimmunoassay was used for neopterin measurement. Six of the seven patients showed increased levels of neopterin either at the onset of RR or 1 month thereafter, and levels declined on prednisone treatment to that seen at the time of diagnosis without reactions. No consistent disease associated cytokine profile was observed in these patients. Interestingly, serum TNF-alpha levels were increased in the same patients even after completion of prednisone treatment, indicating ongoing immune activity. In conclusion, this study demonstrates that despite cytokines levels in leprosy serum being inconsistent in relation to reversal reactions, serum neopterin measurement appears to be an useful biomarker in monitoring RR patients during corticosteroid therapy.

Monitoring Time-Dependent Formation of Oligomers and Brown Carbon in Reactions of Glycolaldehyde, Methylglyoxal, and Amines

NASA Astrophysics Data System (ADS)

Espelien, B.; Galloway, M. M.; De Haan, D. O.

2012-12-01

Authors: Brenna Espelien, Melissa Galloway, and David De Haan The brown carbon components of atmospheric aerosol exhibit strong UV absorbance with a featureless 'tail' that extends into the visible range. Recent work has shown that brown carbon (or HULIS) is formed at least in part by aqueous-phase chemical reactions in the atmosphere. Reactions between aldehydes (such as glycolaldehyde and methylglyoxal) and amines create brown products that have similar light-absorbing spectra as HULIS extracted from atmospheric aerosol. However, the structures of these products have not been well-characterized. Bulk-phase reactions were monitored using LCMS and UV-Vis spectroscopy over a period of 2-3 weeks to see what products formed, whether oligomerization is occurring, and how this correlates with the development of absorbance peaks in the visible range. UV-Vis data shows that these reactions generally take several days to reach maximum absorbance in the visible range. For the glycolaldehyde/glycine reaction, the appearance of a strong absorber at about 400 nm correlated with the appearance of high-mass products at m/z 227, 363, 393, and 431. Additional reactions between aldehydes and amines that quickly produce brown products are being studied. We suggest that imine oligomers are major products of these reactions.

Lysine-Derived Protein-Bound Heyns Compounds in Bakery Products.

PubMed

Treibmann, Stephanie; Hellwig, Anne; Hellwig, Michael; Henle, Thomas

2017-12-06

Fructose and dicarbonyl compounds resulting from fructose in heated foods have been linked to pathophysiological pathways of several metabolic disorders. Up to now, very little has been known about the Maillard reaction of fructose in food. Heyns rearrangement compounds (HRCs), the first stable intermediates of the Maillard reaction between amino components and fructose, have not yet been quantitated as protein-bound products in food. Therefore, the HRCs glucosyllysine and mannosyllysine were synthesized and characterized by NMR. Protein-bound HRCs in cookies containing various sugars and in commercial bakery products were quantitated after enzymatic hydrolysis by RP-HPLC-ESI-MS/MS in the multiple reaction monitoring mode through application of the standard addition method. Protein-bound HRCs were quantitated for the first time in model cookies and in commercial bakery products containing honey, banana, and invert sugar syrup. Concentrations of HRCs from 19 to 287 mg/kg were found, which were similar to or exceeded the content of other frequently analyzed Maillard reaction products, such as N-ε-carboxymethyllysine (10-76 mg/kg), N-ε-carboxyethyllysine (2.5-53 mg/kg), and methylglyoxal-derived hydroimidazolone 1 (10-218 mg/kg) in the analyzed cookies. These results show that substantial amounts of HRCs form during food processing. Analysis of protein-bound HRCs in cookies is therefore useful to evaluate the Maillard reaction of fructose.

Secondary organic aerosol formation from ozone-initiated reactions with nicotine and secondhand tobacco smoke

NASA Astrophysics Data System (ADS)

Sleiman, Mohamad; Destaillats, Hugo; Smith, Jared D.; Liu, Chen-Lin; Ahmed, Musahid; Wilson, Kevin R.; Gundel, Lara A.

2010-11-01

We used controlled laboratory experiments to evaluate the aerosol-forming potential of ozone reactions with nicotine and secondhand smoke. Special attention was devoted to real-time monitoring of the particle size distribution and chemical composition of SOA as they are believed to be key factors determining the toxicity of SOA. The experimental approach was based on using a vacuum ultraviolet photon ionization time-of-flight aerosol mass spectrometer (VUV-AMS), a scanning mobility particle sizer (SMPS) and off-line thermal desorption coupled to mass spectrometry (TD-GC-MS) for gas-phase byproducts analysis. Results showed that exposure of SHS to ozone induced the formation of ultrafine particles (<100 nm) that contained high molecular weight nitrogenated species ( m/ z 400-500), which can be due to accretion/acid-base reactions and formation of oligomers. In addition, nicotine was found to contribute significantly (with yields 4-9%) to the formation of secondary organic aerosol through reaction with ozone. The main constituents of the resulting SOA were tentatively identified and a reaction mechanism was proposed to elucidate their formation. These findings identify a new component of thirdhand smoke that is associated with the formation of ultrafine particles (UFP) through oxidative aging of secondhand smoke. The significance of this chemistry for indoor exposure and health effects is highlighted.

Lanthanide anilido complexes: synthesis, characterization, and use as highly efficient catalysts for hydrophosphonylation of aldehydes and unactivated ketones.

PubMed

Liu, Chengwei; Qian, Qinqin; Nie, Kun; Wang, Yaorong; Shen, Qi; Yuan, Dan; Yao, Yingming

2014-06-14

Lanthanide anilido complexes stabilized by the 2,6-diisopropylanilido ligand have been synthesized and characterized, and their catalytic activity for hydrophosphonylation reaction was explored. A reaction of anhydrous LnCl3 with 5 equivalents of LiNHPh-(I)Pr2-2,6 in THF generated the heterobimetallic lanthanide-lithium anilido complexes (2,6-(I)Pr2PhNH)5LnLi2(THF)2 [Ln = Sm(1), Nd(2), Y(3)] in good isolated yields. These complexes are well characterized by elemental analysis, IR, NMR (for complex ) and single-crystal structure determination. Complexes 1 - 3 are isostructural. In these complexes, the lanthanide metal ion is five-coordinated by five nitrogen atoms from five 2,6-diisopropylanilido ligands to form a distorted trigonal bipyramidal geometry. The lithium ion is coordinated by two nitrogen atoms from two 2,6-diisopropylanilido ligands, and one oxygen atom from a THF molecule. It was found that these simple lanthanide anilido complexes are highly efficient for catalyzing hydrophosphonylation reactions of various aldehydes and unactivated ketones to generate α-hydroxyphosphonates in good to excellent yields (up to 99%) within a short time (5 min for aldehydes, 20 min for ketones). Furthermore, the mechanism of hydrophosphonylation reactions has also been elucidated via(1)H NMR monitoring of reaction.

MRM-DIFF: data processing strategy for differential analysis in large scale MRM-based lipidomics studies.

PubMed

Tsugawa, Hiroshi; Ohta, Erika; Izumi, Yoshihiro; Ogiwara, Atsushi; Yukihira, Daichi; Bamba, Takeshi; Fukusaki, Eiichiro; Arita, Masanori

2014-01-01

Based on theoretically calculated comprehensive lipid libraries, in lipidomics as many as 1000 multiple reaction monitoring (MRM) transitions can be monitored for each single run. On the other hand, lipid analysis from each MRM chromatogram requires tremendous manual efforts to identify and quantify lipid species. Isotopic peaks differing by up to a few atomic masses further complicate analysis. To accelerate the identification and quantification process we developed novel software, MRM-DIFF, for the differential analysis of large-scale MRM assays. It supports a correlation optimized warping (COW) algorithm to align MRM chromatograms and utilizes quality control (QC) sample datasets to automatically adjust the alignment parameters. Moreover, user-defined reference libraries that include the molecular formula, retention time, and MRM transition can be used to identify target lipids and to correct peak abundances by considering isotopic peaks. Here, we demonstrate the software pipeline and introduce key points for MRM-based lipidomics research to reduce the mis-identification and overestimation of lipid profiles. The MRM-DIFF program, example data set and the tutorials are downloadable at the "Standalone software" section of the PRIMe (Platform for RIKEN Metabolomics, http://prime.psc.riken.jp/) database website.

MRM-DIFF: data processing strategy for differential analysis in large scale MRM-based lipidomics studies

PubMed Central

Tsugawa, Hiroshi; Ohta, Erika; Izumi, Yoshihiro; Ogiwara, Atsushi; Yukihira, Daichi; Bamba, Takeshi; Fukusaki, Eiichiro; Arita, Masanori

2015-01-01

Based on theoretically calculated comprehensive lipid libraries, in lipidomics as many as 1000 multiple reaction monitoring (MRM) transitions can be monitored for each single run. On the other hand, lipid analysis from each MRM chromatogram requires tremendous manual efforts to identify and quantify lipid species. Isotopic peaks differing by up to a few atomic masses further complicate analysis. To accelerate the identification and quantification process we developed novel software, MRM-DIFF, for the differential analysis of large-scale MRM assays. It supports a correlation optimized warping (COW) algorithm to align MRM chromatograms and utilizes quality control (QC) sample datasets to automatically adjust the alignment parameters. Moreover, user-defined reference libraries that include the molecular formula, retention time, and MRM transition can be used to identify target lipids and to correct peak abundances by considering isotopic peaks. Here, we demonstrate the software pipeline and introduce key points for MRM-based lipidomics research to reduce the mis-identification and overestimation of lipid profiles. The MRM-DIFF program, example data set and the tutorials are downloadable at the “Standalone software” section of the PRIMe (Platform for RIKEN Metabolomics, http://prime.psc.riken.jp/) database website. PMID:25688256

Development and validation of an indirect pulsed electrochemical detection method for monitoring the inhibition of Abl1 tyrosine kinase.

PubMed

Chen, Hui; Wang, Xu; Chopra, Shruti; Adams, Erwin; Van Schepdael, Ann

2014-03-01

A new method for monitoring the enzyme inhibition of Abl1 tyrosine kinase by liquid chromatography-indirect pulsed electrochemical detection (LC-InPED) was developed. In this method, adsorption of a peptide analyte at the noble metal electrode suppresses the oxidation of polyols under alkaline condition to elicit an indirect response resulting in a negative peak of the target peptide. Among the reagents tested, D-gluconic acid sodium salt gave the best overall signal to noise (S/N) values for the indirect detection of p-Abltide, the product of Abl1 enzymatic reaction. 50 μM D-gluconic acid sodium salt dissolved in a mixture of 78% water-22% acetonitrile-0.03% trifluoroacetic acid (TFA) was used as the mobile phase. Chromatographic separation was achieved on an Alltima C18 (I.D. 5 μm; 250 mm × 4.6 mm) column with the mobile phase flow rate of 0.5 ml/min. 0.5M sodium hydroxide was added post-column to maintain alkaline conditions in the PED cell. The limit of quantification (LOQ) was 0.2 μM for p-Abltide, which was about 50-fold lower than direct PED analysis. The residual plot of the linear calibration curve indicated a good fit with a linear model within the investigated concentration range of p-Abltide. Intra- and inter-day precision was not more than 6.5% and accuracy was from -5.75% to +1.54%. The validated LC-InPED method was successfully applied for monitoring of p-Abltide in Abl1 enzyme reaction and the inhibition study of Abl1. The determined IC50 values of model inhibitors, imatinib, nilotinib and dasatinib, were 601.4 nM (R(2)=0.99), 32.3 nM (R(2)=0.99) and 1.3 nM (R(2)=0.98), respectively. These results were consistent with literature data. To the best of our knowledge this is the first time a LC-InPED method has been used to monitor an enzyme reaction. Copyright © 2013 Elsevier B.V. All rights reserved.

In-line monitoring of cocrystallization process and quantification of carbamazepine-nicotinamide cocrystal using Raman spectroscopy and chemometric tools.

PubMed

Soares, Frederico L F; Carneiro, Renato L

2017-06-05

A cocrystallization process may involve several molecular species, which are generally solid under ambient conditions. Thus, accurate monitoring of different components that might appear during the reaction is necessary, as well as quantification of the final product. This work reports for the first time the synthesis of carbamazepine-nicotinamide cocrystal in aqueous media with a full conversion. The reactions were monitored by Raman spectroscopy coupled with Multivariate Curve Resolution - Alternating Least Squares, and the quantification of the final product among its coformers was performed using Raman spectroscopy and Partial Least Squares regression. The slurry reaction was made in four different conditions: room temperature, 40°C, 60°C and 80°C. The slurry reaction at 80°C enabled a full conversion of initial substrates into the cocrystal form, using water as solvent for a greener method. The employment of MCR-ALS coupled with Raman spectroscopy enabled to observe the main steps of the reactions, such as drug dissolution, nucleation and crystallization of the cocrystal. The PLS models gave mean errors of cross validation around 2.0 (% wt/wt), and errors of validation between 2.5 and 8.2 (% wt/wt) for all components. These were good results since the spectra of cocrystals and the physical mixture of the coformers present some similar peaks. Copyright © 2017 Elsevier B.V. All rights reserved.

In-line monitoring of cocrystallization process and quantification of carbamazepine-nicotinamide cocrystal using Raman spectroscopy and chemometric tools

NASA Astrophysics Data System (ADS)

Soares, Frederico L. F.; Carneiro, Renato L.

2017-06-01

A cocrystallization process may involve several molecular species, which are generally solid under ambient conditions. Thus, accurate monitoring of different components that might appear during the reaction is necessary, as well as quantification of the final product. This work reports for the first time the synthesis of carbamazepine-nicotinamide cocrystal in aqueous media with a full conversion. The reactions were monitored by Raman spectroscopy coupled with Multivariate Curve Resolution - Alternating Least Squares, and the quantification of the final product among its coformers was performed using Raman spectroscopy and Partial Least Squares regression. The slurry reaction was made in four different conditions: room temperature, 40 °C, 60 °C and 80 °C. The slurry reaction at 80 °C enabled a full conversion of initial substrates into the cocrystal form, using water as solvent for a greener method. The employment of MCR-ALS coupled with Raman spectroscopy enabled to observe the main steps of the reactions, such as drug dissolution, nucleation and crystallization of the cocrystal. The PLS models gave mean errors of cross validation around 2.0 (% wt/wt), and errors of validation between 2.5 and 8.2 (% wt/wt) for all components. These were good results since the spectra of cocrystals and the physical mixture of the coformers present some similar peaks.

Kinetics of lisinopril intramolecular cyclization in solid phase monitored by Fourier transform infrared microscopy.

PubMed

Widjaja, Effendi; Tan, Wei Jian

2008-08-01

The solid-state intramolecular cyclization of lisinopril to diketopiperazine was investigated by in situ Fourier transform infrared (FT-IR) microscopy. Using a controllable heating cell, the isothermal transformation was monitored in situ at 147.5, 150, 152.5, 155, and 157.5 degrees C. The collected time-dependent FT-IR spectra at each isothermal temperature were preprocessed and analyzed using a multivariate chemometric approach. The pure component spectra of the observable component (lisinopril and diketopiperazine) were resolved and their time-dependent relative contributions were also determined. Model-free and various model fitting methods were implemented in the kinetic analysis to estimate the activation energy of the intramolecular cyclization reaction. Arrhenius plots indicate that the activation energy is circa 327 kJ/mol.

Sensing Technologies for Detection of Acetone in Human Breath for Diabetes Diagnosis and Monitoring

PubMed Central

Saasa, Valentine; Malwela, Thomas; Beukes, Mervyn; Mokgotho, Matlou; Liu, Chaun-Pu; Mwakikunga, Bonex

2018-01-01

The review describes the technologies used in the field of breath analysis to diagnose and monitor diabetes mellitus. Currently the diagnosis and monitoring of blood glucose and ketone bodies that are used in clinical studies involve the use of blood tests. This method entails pricking fingers for a drop of blood and placing a drop on a sensitive area of a strip which is pre-inserted into an electronic reading instrument. Furthermore, it is painful, invasive and expensive, and can be unsafe if proper handling is not undertaken. Human breath analysis offers a non-invasive and rapid method for detecting various volatile organic compounds thatare indicators for different diseases. In patients with diabetes mellitus, the body produces excess amounts of ketones such as acetoacetate, beta-hydroxybutyrate and acetone. Acetone is exhaled during respiration. The production of acetone is a result of the body metabolising fats instead of glucose to produce energy. There are various techniques that are used to analyse exhaled breath including Gas Chromatography Mass Spectrometry (GC–MS), Proton Transfer Reaction Mass Spectrometry (PTR–MS), Selected Ion Flow Tube-Mass Spectrometry (SIFT–MS), laser photoacoustic spectrometry and so on. All these techniques are not portable, therefore this review places emphasis on how nanotechnology, through semiconductor sensing nanomaterials, has the potential to help individuals living with diabetes mellitus monitor their disease with cheap and portable devices. PMID:29385067

Advancing the sensitivity of selected reaction monitoring-based targeted quantitative proteomics

PubMed Central

Shi, Tujin; Su, Dian; Liu, Tao; Tang, Keqi; Camp, David G.; Qian, Wei-Jun; Smith, Richard D.

2012-01-01

Selected reaction monitoring (SRM)—also known as multiple reaction monitoring (MRM)—has emerged as a promising high-throughput targeted protein quantification technology for candidate biomarker verification and systems biology applications. A major bottleneck for current SRM technology, however, is insufficient sensitivity for e.g., detecting low-abundance biomarkers likely present at the low ng/mL to pg/mL range in human blood plasma or serum, or extremely low-abundance signaling proteins in cells or tissues. Herein we review recent advances in methods and technologies, including front-end immunoaffinity depletion, fractionation, selective enrichment of target proteins/peptides including posttranslational modifications (PTMs), as well as advances in MS instrumentation which have significantly enhanced the overall sensitivity of SRM assays and enabled the detection of low-abundance proteins at low to sub- ng/mL level in human blood plasma or serum. General perspectives on the potential of achieving sufficient sensitivity for detection of pg/mL level proteins in plasma are also discussed. PMID:22577010

Advancing the sensitivity of selected reaction monitoring-based targeted quantitative proteomics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Shi, Tujin; Su, Dian; Liu, Tao

2012-04-01

Selected reaction monitoring (SRM)—also known as multiple reaction monitoring (MRM)—has emerged as a promising high-throughput targeted protein quantification technology for candidate biomarker verification and systems biology applications. A major bottleneck for current SRM technology, however, is insufficient sensitivity for e.g., detecting low-abundance biomarkers likely present at the pg/mL to low ng/mL range in human blood plasma or serum, or extremely low-abundance signaling proteins in the cells or tissues. Herein we review recent advances in methods and technologies, including front-end immunoaffinity depletion, fractionation, selective enrichment of target proteins/peptides or their posttranslational modifications (PTMs), as well as advances in MS instrumentation, whichmore » have significantly enhanced the overall sensitivity of SRM assays and enabled the detection of low-abundance proteins at low to sub- ng/mL level in human blood plasma or serum. General perspectives on the potential of achieving sufficient sensitivity for detection of pg/mL level proteins in plasma are also discussed.« less

Detection and Site Localization of Phosphorylcholine-Modified Peptides by NanoLC-ESI-MS/MS Using Precursor Ion Scanning and Multiple Reaction Monitoring Experiments

NASA Astrophysics Data System (ADS)

Timm, Thomas; Lenz, Christof; Merkel, Dietrich; Sadiffo, Christian; Grabitzki, Julia; Klein, Jochen; Lochnit, Guenter

2015-03-01

Phosphorylcholine (PC)-modified biomolecules like lipopolysaccharides, glycosphingolipids, and (glyco)proteins are widespread, highly relevant antigens of parasites, since this small hapten shows potent immunomodulatory capacity, which allows the establishment of long-lasting infections of the host. Especially for PC-modified proteins, structural data is rare because of the zwitterionic nature of the PC substituent, resulting in low sensitivities and unusual but characteristic fragmentation patterns. We have developed a targeted mass spectrometric approach using hybrid triple quadrupole/linear ion trap (QTRAP) mass spectrometry coupled to nanoflow chromatography for the sensitive detection of PC-modified peptides from complex proteolytic digests, and the localization of the PC-modification within the peptide backbone. In a first step, proteolytic digests are screened using precursor ion scanning for the marker ions of choline ( m/z 104.1) and phosphorylcholine ( m/z 184.1) to establish the presence of PC-modified peptides. Potential PC-modified precursors are then subjected to a second analysis using multiple reaction monitoring (MRM)-triggered product ion spectra for the identification and site localization of the modified peptides. The approach was first established using synthetic PC-modified synthetic peptides and PC-modified model digests. Following the optimization of key parameters, we then successfully applied the method to the detection of PC-peptides in the background of a proteolytic digest of a whole proteome. This methodological invention will greatly facilitate the detection of PC-substituted biomolecules and their structural analysis.

Development of a polydimethylsiloxane-thymol/nitroprusside composite based sensor involving thymol derivatization for ammonium monitoring in water samples.

PubMed

Prieto-Blanco, M C; Jornet-Martínez, N; Moliner-Martínez, Y; Molins-Legua, C; Herráez-Hernández, R; Verdú Andrés, J; Campins-Falcó, P

2015-01-15

This report describes a polydimethylsiloxane (PDMS)-thymol/nitroprusside delivery composite sensor for direct monitoring of ammonium in environmental water samples. The sensor is based on a PDMS support that contains the Berthelot's reaction reagents. To prepare the PDMS-thymol/nitroprusside composite discs, thymol and nitroprusside have been encapsulated in the PDMS matrix, forming a reagent release support which significantly simplifies the analytical measurements, since it avoids the need to prepare derivatizing reagents and sample handling is reduced to the sampling step. When, the PDMS-thymol/nitroprusside composite was introduced in water samples spontaneous release of the chromophore and catalyst was produced, and the derivatization reaction took place to form the indothymol blue. Thus, qualitative analysis of NH4(+) could be carried out by visual inspection, but also, it can be quantified by measuring the absorbance at 690 nm. These portable devices provided good sensitivity (LOD<0.4 mg L(-1)) and reproducibility (RSD <10%) for the rapid detection of ammonium. The PDMS-NH4(+) sensor has been successfully applied to determine ammonium in water samples and in the aqueous extracts of particulate matter PM10 samples. Moreover, the reliability of the method for qualitative analysis has been demonstrated. Finally, the advantages of the PDMS-NH4(+) sensor have been examined by comparing some analytical and complementary characteristics with the properties of well-established ammonium determination methods. Copyright © 2014 Elsevier B.V. All rights reserved.

Low energy measurements of the 10B(p ,α )7Be reaction

NASA Astrophysics Data System (ADS)

Wiescher, M.; deBoer, R. J.; Görres, J.; Azuma, R. E.

2017-04-01

Background: The 11B(p,2 α ) 4He reaction is being discussed as a prime candidate for advanced aneutronic fusion fuel systems. Particular interest in this reaction has recently emerged for laser driven plasma systems for energy generation and jet-propulsion systems. The lack of long-lived radioactive reaction products has been suggested as the main advantage of proton-boron fusion fuel. However, 19% of natural boron is 10B, with the 10B(p ,α )7Be fusion reaction producing long-lived 7Be as a side product. Purpose: A detailed measurement of the 10B(p ,α )7Be reaction over the critical energy range of hot fusion plasma environments will help to determine the amount of 7Be radioactivity being produced. This information can be used in turn to monitor the actual fusion temperature by offline measurement of the extracted 7Be activity. The goal of the here presented experiment is to expand on the results of earlier experiments, covering a wider energy range of interest for aneutronic plasma fusion applications, including also both 10B(p ,α0)7Be and the 10B(p ,α1)7Be reaction channels. Method: The reaction cross section was measured over a wide energy range from Ep=400 to 1000 keV using particle detection and from Ep=80 to 1440 keV using γ -ray spectroscopic techniques. Reaction α particles were measured at different angles to obtain angular distribution information. The results are discussed in terms of an R -matrix analysis. Results: The cross section data cover a wider energy range than previously investigated and bridge a gap in the previously available data sets. The cross sections show good agreement with previous results in the low energy region and show that the 10B(p ,α0)7Be channel is considerably larger than that of the 10B(p ,α1)7Be channel up to Ep≈1 MeV . Conclusions: The new reaction data provides important new information about the reaction cross section over the entire energy range of plasma fusion facilities. This data, when coupled with previous measurement of the competing 10B(p ,γ )11C reaction, will provide the opportunity for an extensive R -matrix analysis of the rather complex level structure in the 11C compound nucleus system.

Automatic NMR-Based Identification of Chemical Reaction Types in Mixtures of Co-Occurring Reactions

PubMed Central

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 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 elucidation of the molecules in the mixtures. PMID:24551112

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

PubMed

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 the molecules in the mixtures.

Monitoring binding affinity between drug and α1-acid glycoprotein in real time by Venturi easy ambient sonic-spray ionization mass spectrometry.

PubMed

Liu, Ning; Lu, Xin; Yang, YuHan; Yao, Chen Xi; Ning, BaoMing; He, Dacheng; He, Lan; Ouyang, Jin

2015-10-01

A new approach for monitoring the binding affinity between drugs and alpha 1-acid glycoprotein in real time was developed based on a combination of drug-protein reaction followed by Venturi easy ambient sonic-spray ionization mass spectrometry determination of the free drug concentrations. A known basic drug, propranolol was used to validate the new built method. Binding constant values calculated by venturi easy ambient sonic-spray ionization mass spectrometry was in good accordance with a traditional ultrafiltration combined with high performance liquid chromatography method. Then six types of basic drugs were used as the samples to conduct the real time analysis. Upon injection of alpha 1-acid glycoprotein to the drug mixture, the ion chromatograms were extracted to show the changes in the free drug concentrations in real time. By observing the drop-out of six types of drugs during the whole binding reaction, the binding affinities of different drugs were distinguished. A volume shift validating experiment and an injection delay correcting experiment were also performed to eliminate extraneous factors and verify the reliability of our experiment. Therefore, the features of Venturi easy ambient sonic-spray ionization mass spectrometry (V-EASI-MS) and the experimental results indicate that our technique is likely to become a powerful tool for monitoring drug-AGP binding affinity in real time. Copyright © 2015 Elsevier B.V. All rights reserved.

Detection of Onchocerca volvulus in Skin Snips by Microscopy and Real-Time Polymerase Chain Reaction: Implications for Monitoring and Evaluation Activities.

PubMed

Thiele, Elizabeth A; Cama, Vitaliano A; Lakwo, Thomson; Mekasha, Sindeaw; Abanyie, Francisca; Sleshi, Markos; Kebede, Amha; Cantey, Paul T

2016-04-01

Microscopic evaluation of skin biopsies is the monitoring and evaluation (M and E) method currently used by multiple onchocerciasis elimination programs in Africa. However, as repeated mass drug administration suppresses microfilarial loads, the sensitivity and programmatic utility of skin snip microscopy is expected to decrease. Using a pan-filarial real-time polymerase chain reaction with melt curve analysis (qPCR-MCA), we evaluated 1) the use of a single-step molecular assay for detecting and identifying Onchocerca volvulus microfilariae in residual skin snips and 2) the sensitivity of skin snip microscopy relative to qPCR-MCA. Skin snips were collected and examined with routine microscopy in hyperendemic regions of Uganda and Ethiopia (N= 500 each) and "residual" skin snips (tissue remaining after induced microfilarial emergence) were tested with qPCR-MCA. qPCR-MCA detected Onchocerca DNA in 223 residual snips: 139 of 147 microscopy(+) and 84 among microscopy(-) snips, suggesting overall sensitivity of microscopy was 62.3% (139/223) relative to qPCR-MCA (75.6% in Uganda and 28.6% in Ethiopia). These findings demonstrate the insufficient sensitivity of skin snip microscopy for reliable programmatic monitoring. Molecular tools such as qPCR-MCA can augment sensitivity and provide diagnostic confirmation of skin biopsies and will be useful for evaluation or validation of new onchocerciasis M and E tools. © The American Society of Tropical Medicine and Hygiene.

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

PubMed

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 < 0.001), and more likely to be type A reactions (73.5% vs. 18.8%, p < 0.001). Females were over-represented among drug-induced adverse reactions (68.1%, p < 0.001) but not among 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 < 0.001). We found differences in sex, preventability, severity, and type A/B reactions between spontaneously reported drug and contrast media-induced adverse reactions. The World Health Organization-Uppsala Monitoring Centre and Naranjo algorithm causality evaluation afforded similar results.

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

PubMed Central

Suh, JinUk; Yang, MyungSuk; Kang, WonKu; Kim, EunYoung

2015-01-01

Objective We analyzed differences between spontaneously reported drug-induced (not including contrast media) and contrast media-induced adverse reactions. Methods 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. Results 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 < 0.001), and more likely to be type A reactions (73.5% vs. 18.8%, p < 0.001). Females were over-represented among drug-induced adverse reactions (68.1%, p < 0.001) but not among 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 < 0.001). Conclusions We found differences in sex, preventability, severity, and type A/B reactions between spontaneously reported drug and contrast media-induced adverse reactions. The World Health Organization–Uppsala Monitoring Centre and Naranjo algorithm causality evaluation afforded similar results. PMID:26544039

Selective determination of pyridine alkaloids in tobacco by PFTBA ions/analyte molecule reaction ionization ion trap mass spectrometry.

PubMed

Zhang, Jianxun; Ji, Houwei; Sun, Shihao; Mao, Duobin; Liu, Huwei; Guo, Yinlong

2007-10-01

The application of perfluorotributylamine (PFTBA) ions/analyte molecule reaction ionization for the selective determination of tobacco pyridine alkaloids by ion trap mass spectrometry (IT-MS) is reported. The main three PFTBA ions (CF(3)(+), C(3)F(5)(+), and C(5)F(10)N(+)) are generated in the external source and then introduced into ion trap for reaction with analytes. Because the existence of the tertiary nitrogen atom in the pyridine makes it possible for PFTBA ions to react smoothly with pyridine and forms adduct ions, pyridine alkaloids in tobacco were selectively ionized and formed quasi-molecular ion [M + H](+)and adduct ions, including [M + 69](+), [M + 131](+), and [M + 264](+), in IT-MS. These ions had distinct abundances and were regarded as the diagnostic ions of each tobacco pyridine alkaloid for quantitative analysis in selected-ion monitoring mode. Results show that the limit of detection is 0.2 microg/mL, and the relative standard deviations for the seven alkaloids are in the range of 0.71% to 6.8%, and good recovery of 95.6% and 97.2%. The proposed method provides substantially greater selectivity and sensitivity compared with the conventional approach and offers an alternative approach for analysis of tobacco alkaloids.

[The validation of kit of reagents for quantitative detection of DNA of human cytomegalovirus in biological material using polymerase chain reaction technique in real time operation mode].

PubMed

Sil'veĭstrova, O Iu; Domonova, É A; Shipulina, O Iu

2014-04-01

The validation of kit of reagents destined to detection and quantitative evaluation of DNA of human cytomegalovirus in biological material using polymerase chain reaction technique in real time operation mode was implemented. The comparison was made against international WHO standard--The first WHO international standard for human cytomegalovirus to implement measures the kit of reagents "AmpliSens CMV-screen/monitor-FL" and standard sample of enterprise DNA HCMV (The central research institute of epidemiology of Rospotrebnadzor) was applied. The fivefold dilution of international WHO standard and standard sample of enterprise were carried out in concentrations of DNA HCMV from 106 to 102. The arrangement of polymerase chain reaction and analysis of results were implemented using programed amplifier with system of detection of fluorescent signal in real-time mode "Rotor-Gene Q" ("Qiagen", Germany). In the total of three series of experiments, all stages of polymerase chain reaction study included, the coefficient of translation of quantitative evaluation of DNA HCMV from copy/ml to ME/ml equal to 0.6 was introduced for this kit of reagents.

Online Monitoring of Methanol Electro-Oxidation Reactions by Ambient Mass Spectrometry

NASA Astrophysics Data System (ADS)

Cheng, Si; Wu, Qiuhua; Dewald, Howard D.; Chen, Hao

2017-06-01

Online detection of methanol electro-oxidation reaction products [e.g., formaldehyde (HCHO)] by mass spectrometry (MS) is challenging, owing to the high salt content and extreme pH of the electrolyte solution as well as the difficulty in ionizing the reaction products. Herein we present an online ambient mass spectrometric approach for analyzing HCHO generated from methanol electro-oxidation, taking the advantage of high salt tolerance of desorption electrospray ionization mass spectrometry (DESI-MS). It was found that HCHO can be detected as PhNHNH+=CH2 ( m/z 121) by DESI after online derivatization with PhNHNH2. With this approach, the analysis of HCHO from methanol electro-oxidation by MS was carried out not only in acidic condition but also in alkaline media for the first time. Efficiencies of different electrodes for methanol oxidation at different pHs were also evaluated. Our results show that Au electrode produces more HCHO than Pt-based electrodes at alkaline pH, while the latter have higher yields at acidic solution. The presented methodology would be of great value for elucidating fuel cell reaction mechanisms and for screening ideal fuel cell electrode materials. [Figure not available: see fulltext.

Predictive modeling in Clostridium acetobutylicum fermentations employing Raman spectroscopy and multivariate data analysis for real-time culture monitoring

NASA Astrophysics Data System (ADS)

Zu, Theresah N. K.; Liu, Sanchao; Germane, Katherine L.; Servinsky, Matthew D.; Gerlach, Elliot S.; Mackie, David M.; Sund, Christian J.

2016-05-01

The coupling of optical fibers with Raman instrumentation has proven to be effective for real-time monitoring of chemical reactions and fermentations when combined with multivariate statistical data analysis. Raman spectroscopy is relatively fast, with little interference from the water peak present in fermentation media. Medical research has explored this technique for analysis of mammalian cultures for potential diagnosis of some cancers. Other organisms studied via this route include Escherichia coli, Saccharomyces cerevisiae, and some Bacillus sp., though very little work has been performed on Clostridium acetobutylicum cultures. C. acetobutylicum is a gram-positive anaerobic bacterium, which is highly sought after due to its ability to use a broad spectrum of substrates and produce useful byproducts through the well-known Acetone-Butanol-Ethanol (ABE) fermentation. In this work, real-time Raman data was acquired from C. acetobutylicum cultures grown on glucose. Samples were collected concurrently for comparative off-line product analysis. Partial-least squares (PLS) models were built both for agitated cultures and for static cultures from both datasets. Media components and metabolites monitored include glucose, butyric acid, acetic acid, and butanol. Models were cross-validated with independent datasets. Experiments with agitation were more favorable for modeling with goodness of fit (QY) values of 0.99 and goodness of prediction (Q2Y) values of 0.98. Static experiments did not model as well as agitated experiments. Raman results showed the static experiments were chaotic, especially during and shortly after manual sampling.

Smokers' Views on Personal Carbon Monoxide Monitors, Associated Apps, and Their Use: An Interview and Think-Aloud Study.

PubMed

Herbeć, Aleksandra; Perski, Olga; Shahab, Lion; West, Robert

2018-02-07

Smartphone-based personal carbon monoxide (CO) monitors and associated apps, or "CO Smartphone Systems" (CSSs) for short, could enable smokers to independently monitor their smoking and quitting. This study explored views and preferences regarding CSSs and their use among 16 adult, UK-based smokers. First, semi-structured interviews explored participants' expectations of CSSs. Secondly, a think-aloud study identified participants' reactions to a personal CO monitor and to existing or prototype apps. Framework Analysis identified five themes: (1) General views, needs, and motivation to use CSSs; (2) Views on the personal CO monitor; (3) Practicalities of CSS use; (4) Desired features in associated apps; and (5) Factors affecting preferences for CSSs and their use. Participants had high expectations of CSSs and their potential to increase motivation. Priority app features included: easy CO testing journeys, relevant and motivating feedback, and recording of contextual data. Appearance and usability of the personal CO monitor, and accuracy and relevance of CO testing were considered important for engagement. Participants differed in their motivation to use and preferences for CSSs features and use, which might have non-trivial impact on evaluation efforts. Personal CO monitors and associated apps may be attractive tools for smokers, but making CSSs easy to use and evaluating these among different groups of smokers may be challenging.

In vivo bioluminescence imaging of cell differentiation in biomaterials: a platform for scaffold development.

PubMed

Bagó, Juli R; Aguilar, Elisabeth; Alieva, Maria; Soler-Botija, Carolina; Vila, Olaia F; Claros, Silvia; Andrades, José A; Becerra, José; Rubio, Nuria; Blanco, Jerónimo

2013-03-01

In vivo testing is a mandatory last step in scaffold development. Agile longitudinal noninvasive real-time monitoring of stem cell behavior in biomaterials implanted in live animals should facilitate the development of scaffolds for tissue engineering. We report on a noninvasive bioluminescence imaging (BLI) procedure for simultaneous monitoring of changes in the expression of multiple genes to evaluate scaffold performance in vivo. Adipose tissue-derived stromal mensenchymal cells were dually labeled with Renilla red fluorescent protein and firefly green fluorescent protein chimeric reporters regulated by cytomegalovirus and tissue-specific promoters, respectively. Labeled cells were induced to differentiate in vitro and in vivo, by seeding in demineralized bone matrices (DBMs) and monitored by BLI. Imaging results were validated by RT-polymerase chain reaction and histological procedures. The proposed approach improves molecular imaging and measurement of changes in gene expression of cells implanted in live animals. This procedure, applicable to the simultaneous analysis of multiple genes from cells seeded in DBMs, should facilitate engineering of scaffolds for tissue repair.

In Vivo Bioluminescence Imaging of Cell Differentiation in Biomaterials: A Platform for Scaffold Development

PubMed Central

Bagó, Juli R.; Aguilar, Elisabeth; Alieva, Maria; Soler-Botija, Carolina; Vila, Olaia F.; Claros, Silvia; Andrades, José A.; Becerra, José; Rubio, Nuria

2013-01-01

In vivo testing is a mandatory last step in scaffold development. Agile longitudinal noninvasive real-time monitoring of stem cell behavior in biomaterials implanted in live animals should facilitate the development of scaffolds for tissue engineering. We report on a noninvasive bioluminescence imaging (BLI) procedure for simultaneous monitoring of changes in the expression of multiple genes to evaluate scaffold performance in vivo. Adipose tissue-derived stromal mensenchymal cells were dually labeled with Renilla red fluorescent protein and firefly green fluorescent protein chimeric reporters regulated by cytomegalovirus and tissue-specific promoters, respectively. Labeled cells were induced to differentiate in vitro and in vivo, by seeding in demineralized bone matrices (DBMs) and monitored by BLI. Imaging results were validated by RT-polymerase chain reaction and histological procedures. The proposed approach improves molecular imaging and measurement of changes in gene expression of cells implanted in live animals. This procedure, applicable to the simultaneous analysis of multiple genes from cells seeded in DBMs, should facilitate engineering of scaffolds for tissue repair. PMID:23013334

In-situ measurement of thermoset resin degree of cure using embedded fiber optic

NASA Astrophysics Data System (ADS)

Breglio, Giovanni; Cusano, Andrea; Cutolo, Antonello; Calabro, Antonio M.; Cantoni, Stefania; Di Vita, Gandolfo; Buonocore, Vincenzo; Giordano, Michele; Nicolais, Luigi, II

1999-12-01

In this work, a fiber optic sensor based on Fresnel principle is presented. It is used to monitor the variations of the refractive index due to the cure process of an epoxy based resin. These materials are widely used in polymer- matrix composites. The process of thermoset matrix based composite involves mass and heat transfer coupled with irreversible chemical reactions inducing physical changes: the transformation of a fluid resin into a rubber and then into a solid glass. To improve the quality and the reliability of these materials key points are the cure monitoring and the optimization of the manufacturing process. To this aim, the fiber optic embedded sensor has been designed, developed and tested. Preliminary results on sensor capability to monitor the cure kinetics are shown. Correlation between the sensor output and conversion advancement has been proposed following the Lorentz-Lorenz law. Isothermal data form the sensor have been compared with calorimetric analysis of an epoxy based resin.

Proton mediated control of biochemical reactions with bioelectronic pH modulation

NASA Astrophysics Data System (ADS)

Deng, Yingxin; Miyake, Takeo; Keene, Scott; Josberger, Erik E.; Rolandi, Marco

2016-04-01

In Nature, protons (H+) can mediate metabolic process through enzymatic reactions. Examples include glucose oxidation with glucose dehydrogenase to regulate blood glucose level, alcohol dissolution into carboxylic acid through alcohol dehydrogenase, and voltage-regulated H+ channels activating bioluminescence in firefly and jellyfish. Artificial devices that control H+ currents and H+ concentration (pH) are able to actively influence biochemical processes. Here, we demonstrate a biotransducer that monitors and actively regulates pH-responsive enzymatic reactions by monitoring and controlling the flow of H+ between PdHx contacts and solution. The present transducer records bistable pH modulation from an “enzymatic flip-flop” circuit that comprises glucose dehydrogenase and alcohol dehydrogenase. The transducer also controls bioluminescence from firefly luciferase by affecting solution pH.

Real-time monitoring of disintegration activity of catalytic core domain of HIV-1 integrase using molecular beacon.

PubMed

Zhang, Da-wei; Zhao, Ming-ming; He, Hong-qiu; Guo, Shun-xing

2013-09-15

HIV-1 integrase, an essential enzyme for retroviral replication, is a validated target for anti-HIV therapy development. The catalytic core domain of integrase (IN-CCD) is capable of catalyzing disintegration reaction. In this work, a hairpin-shaped disintegration substrate was designed and validated by enzyme-linked immunosorbent assay; a molecular beacon-based assay was developed for disintegration reaction of IN-CCD. Results showed that the disintegration substrate could be recognized and catalyzed by IN-CCD, and the disintegration reaction can be monitored according to the increase of fluorescent signal. The assay can be applied to real-time detection of disintegration with advantages of simplicity, high sensitivity, and excellent specificity. Copyright © 2013 Elsevier Inc. All rights reserved.

Quantitative liquid chromatography-mass spectrometry-multiple reaction monitoring (LC-MS-MRM) analysis of site-specific glycoforms of haptoglobin in liver disease.

PubMed

Sanda, Miloslav; Pompach, Petr; Brnakova, Zuzana; Wu, Jing; Makambi, Kepher; Goldman, Radoslav

2013-05-01

Development of liver disease is associated with the appearance of multiply fucosylated glycoforms of haptoglobin. To analyze the disease-related haptoglobin glycoforms in liver cirrhosis and hepatocellular carcinoma, we have optimized an LC-MS-multiple reaction monitoring (MRM) workflow for glycopeptide quantification. The final quantitative analysis included 24 site-specific glycoforms generated by treatment of a tryptic digest of haptoglobin with α(2-3,6,8)-neuraminidase and β(1-4)-galactosidase. The combination of LC-MS-MRM with exoglycosidase digests allowed resolution of isobaric glycoforms of the haptoglobin-T3 glycopeptide for quantification of the multiply fucosylated Lewis Y-containing glycoforms we have identified in the context of liver disease. Fourteen multiply fucosylated glycoforms of the 20 examined increased significantly in the liver disease group compared with healthy controls with an average 5-fold increase in intensity (p < 0.05). At the same time, two tri-antennary glycoforms without fucoses did not increase in the liver disease group, and two tetra-antennary glycoforms without fucoses showed a marginal increase (at most 40%) in intensity. Our analysis of 30 individual patient samples (10 healthy controls, 10 cirrhosis patients, and 10 hepatocellular carcinoma patients) showed that these glycoforms were substantially increased in a small subgroup of liver disease patients but did not significantly differ between the groups of hepatocellular carcinoma and cirrhosis patients. The tri- and tetra-antennary singly fucosylated glycoforms are associated with a MELD score and low platelet counts (p < 0.05). The exoglycosidase-assisted LC-MS-MRM workflow, optimized for the quantification of fucosylated glycoforms of haptoglobin, can be used for quantification of these glycoforms on other glycopeptides with appropriate analytical behavior.

Quantitative Liquid Chromatography-Mass Spectrometry-Multiple Reaction Monitoring (LC-MS-MRM) Analysis of Site-specific Glycoforms of Haptoglobin in Liver Disease*

PubMed Central

Sanda, Miloslav; Pompach, Petr; Brnakova, Zuzana; Wu, Jing; Makambi, Kepher; Goldman, Radoslav

2013-01-01

Development of liver disease is associated with the appearance of multiply fucosylated glycoforms of haptoglobin. To analyze the disease-related haptoglobin glycoforms in liver cirrhosis and hepatocellular carcinoma, we have optimized an LC-MS-multiple reaction monitoring (MRM) workflow for glycopeptide quantification. The final quantitative analysis included 24 site-specific glycoforms generated by treatment of a tryptic digest of haptoglobin with α(2–3,6,8)-neuraminidase and β(1–4)-galactosidase. The combination of LC-MS-MRM with exoglycosidase digests allowed resolution of isobaric glycoforms of the haptoglobin-T3 glycopeptide for quantification of the multiply fucosylated Lewis Y-containing glycoforms we have identified in the context of liver disease. Fourteen multiply fucosylated glycoforms of the 20 examined increased significantly in the liver disease group compared with healthy controls with an average 5-fold increase in intensity (p < 0.05). At the same time, two tri-antennary glycoforms without fucoses did not increase in the liver disease group, and two tetra-antennary glycoforms without fucoses showed a marginal increase (at most 40%) in intensity. Our analysis of 30 individual patient samples (10 healthy controls, 10 cirrhosis patients, and 10 hepatocellular carcinoma patients) showed that these glycoforms were substantially increased in a small subgroup of liver disease patients but did not significantly differ between the groups of hepatocellular carcinoma and cirrhosis patients. The tri- and tetra-antennary singly fucosylated glycoforms are associated with a MELD score and low platelet counts (p < 0.05). The exoglycosidase-assisted LC-MS-MRM workflow, optimized for the quantification of fucosylated glycoforms of haptoglobin, can be used for quantification of these glycoforms on other glycopeptides with appropriate analytical behavior. PMID:23389048

Operando characterization of catalysts through use of a portable microreactor

DOE PAGES

Zhao, Shen; Li, Yuanyuan; Stavitski, Eli; ...

2015-10-09

To provide new understandings of the mechanisms of catalytic reactions, improved methods are needed than can monitor changes in the electronic, structural and chemical properties of catalysts, doing so in the operando conditions in which catalysts work. We describe here a microreactor-based approach that integrates the capabilities of advanced x-ray, electron, optical and gas-phase compositional analysis techniques in operando conditions. For several exemplary catalytic systems, we demonstrate how this approach enables characterization of three major factors contributing to structure-property correlations evidenced in heterogeneously catalyzed reactions, namely: the atomic structure and elemental compositions of nanocatalysts; the physiochemical properties of the supportmore » and catalyst-support interfaces; and the gas and surface-phase chemistry occurring under operando conditions. We highlight the generality of the approach as well as outline opportunities for future developments.« less

How to recognize a “Beast Quake” and a “Dance Quake”

USGS Publications Warehouse

Malone, Stephen; Hall, Kelley; Simmons, Lynn; Vidale, John

2015-01-01

Any good seismologist–carryball (i.e., American football) fan remembers the “beast quake” of 2011. Seahawks fans’ exuberant reactions to a Marshawn Lynch (in beast mode) run caused the stadium to shake enough to be well recorded on a strong‐motion seismograph a block away (Vidale, 2011). With the Seahawks at home for the National Football Conference (NFC) Championship playoffs, both last year and this year, the Pacific Northwest Seismic Network (PNSN) received permission to install some seismometers in the stadium. Motivations for the experiment included testing the field and telemetry equipment, examining analysis and display techniques, and practicing quick reactions to mobilize field experiments. With PNSN students and staff who are also Seahawks fans, it was not hard to get volunteers to do the installations and monitor the on‐field actions and the resulting seismograms.

Acoustical experiment of yogurt fermentation process.

PubMed

Ogasawara, H; Mizutani, K; Ohbuchi, T; Nakamura, T

2006-12-22

One of the important factors through food manufacturing is hygienic management. Thus, food manufactures prove their hygienic activities by taking certifications like a Hazard Analysis and Critical Control Point (HACCP). This concept also applies to food monitoring. Acoustical measurements have advantage for other measurement in food monitoring because they make it possible to measure with noncontact and nondestructive. We tried to monitor lactic fermentation of yogurt by a probing sensor using a pair of acoustic transducers. Temperature of the solution changes by the reaction heat of fermentation. Consequently the sound velocity propagated through the solution also changes depending on the temperature. At the same time, the solution change its phase from liquid to gel. The transducers usage in the solution indicates the change of the temperature as the change of the phase difference between two transducers. The acoustic method has advantages of nondestructive measurement that reduces contamination of food product by measuring instrument. The sensor was inserted into milk with lactic acid bacterial stain of 19 degrees C and monitored phase retardation of propagated acoustic wave and its temperature with thermocouples in the mild. The monitoring result of fermentation from milk to Caspian Sea yogurt by the acoustic transducers with the frequency of 3.7 MHz started to show gradient change in temperature caused by reaction heat of fermentation but stop the gradient change at the end although the temperature still change. The gradient change stopped its change because of phase change from liquid to gel. The present method will be able to measure indirectly by setting transducers outside of the measuring object. This noncontact sensing method will have great advantage of reduces risk of food contamination from measuring instrument because the measurement probes are set out of fermentation reactor or food containers. Our proposed method will contribute to the hygienization for the food manufacture industry.

A vehicle health monitoring system for the Space Shuttle Reaction Control System during reentry. M.S. Thesis - Massachusetts Inst. of Technology

NASA Technical Reports Server (NTRS)

Rosello, Anthony David

1995-01-01

A general two tier framework for vehicle health monitoring of Guidance Navigation and Control (GN&C) system actuators, effectors, and propulsion devices is presented. In this context, a top level monitor that estimates jet thrust is designed for the Space Shuttle Reaction Control System (RCS) during the reentry phase of flight. Issues of importance for the use of estimation technologies in vehicle health monitoring are investigated and quantified for the Shuttle RCS demonstration application. These issues include rate of convergence, robustness to unmodeled dynamics, sensor quality, sensor data rates, and information recording objectives. Closed loop simulations indicate that a Kalman filter design is sensitive to modeling error and robust estimators may reduce this sensitivity. Jet plume interaction with the aerodynamic flowfield is shown to be a significant effect adversely impacting the ability to accurately estimate thrust.

High temperature chemical kinetic study of the H2-CO-CO2-NO reaction system

NASA Technical Reports Server (NTRS)

Jachimowski, C. J.

1975-01-01

An experimental study of the kinetics of the H2-CO-CO2-NO reaction system was made behind incident shock waves at temperatures of 2460 and 2950 K. The overall rate of the reaction was measured by monitoring radiation from the CO + O yields CO2 + h upoilon reaction. Correlation of these data with a detailed reaction mechanism showed that the high-temperature rate of the reaction N + OH yields NO + H can be described by the low-temperature (320 K) rate coefficient. Catalytic dissociation of molecular hydrogen was an important reaction under the tests conditions.

Multichannel quench-flow microreactor chip for parallel reaction monitoring.

PubMed

Bula, Wojciech P; Verboom, Willem; Reinhoudt, David N; Gardeniers, Han J G E

2007-12-01

This paper describes a multichannel silicon-glass microreactor which has been utilized to investigate the kinetics of a Knoevenagel condensation reaction under different reaction conditions. The reaction is performed on the chip in four parallel channels under identical conditions but with different residence times. A special topology of the reaction coils overcomes the common problem arising from the difference in pressure drop of parallel channels having different length. The parallelization of reaction coils combined with chemical quenching at specific locations results in a considerable reduction in experimental effort and cost. The system was tested and showed good reproducibility in flow properties and reaction kinetic data generation.

Optical fiber-based on-line UV/Vis spectroscopic monitoring of chemical reaction kinetics under high pressure in a capillary microreactor.

PubMed

Benito-Lopez, Fernando; Verboom, Willem; Kakuta, Masaya; Gardeniers, J Han G E; Egberink, Richard J M; Oosterbroek, Edwin R; van den Berg, Albert; Reinhoudt, David N

2005-06-14

With a miniaturized (3 microL volume) fiber-optics based system for on-line measurement by UV/Vis spectroscopy, the reaction rate constants (at different pressures) and the activation volumes (deltaV(not =)) were determined for a nucleophilic aromatic substitution and an aza Diels-Alder reaction in a capillary microreactor.

[Suspected adverse reactions after vaccination. Results from the German Health Interview and Examination Survey for Children and Adolescents. Part 2: predictors of parental reporting of suspected adverse reactions after vaccinations].

PubMed

Poethko-Müller, C; Atzpodien, K; Schmitz, R; Schlaud, M

2011-03-01

Each method to monitor vaccine safety has strengths and limitations. Therefore, vaccine safety monitoring should rely on different types of data sources. Methods commonly rely on patient-reported adverse reactions. Little is, however, known about factors that may affect the probability with which patients report adverse reactions to vaccines. From 2003-2006, the representative National Health Interview and Examination Survey for Children and Adolescents ("Kinder- und Jugendgesundheitssurvey", KiGGS) retrospectively collected information about vaccines, vaccination dates, and suspected vaccine related adverse reactions from a total of 17,641 participants (<17 years). Poorly tolerated vaccinations were more likely reported from parents living in former West Germany compared to former East Germany (OR 1.61; 95% CI 1.08-2.39), parents of children with special health care needs (OR 1.49; 95% CI 1.08-2.04), and from parents reporting reservations against vaccinations (OR 3.29; 95% CI 2.28-4.75). Parental reporting of adverse vaccine reactions appears to be associated with parental perception and assessment of possible adverse vaccine reactions, as well as with the parents' attitude towards immunization in general.

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

PubMed

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.

Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution: II. Polycondensations

NASA Technical Reports Server (NTRS)

Kolb, V.; Orgel, L. E.

1995-01-01

We have prepared a [32P]-labeled oligonucleotide probe carrying a ureido (-NH-CO-NH2) function at its 3'-terminus. This labeled oligomer was used to study polycondensations of urea and formaldehyde and of various phenols and formaldehyde in aqueous solution. The formation of formaldehyde copolymers attached to the amido-function of the probe was monitored by gel electrophoresis. Our results are generally in agreement with those obtained using conventional techniques. Our method is suitable for monitoring potentially prebiotic polycondensation reactions involving formaldehyde.

Oligonucleotides as probes for studying polymerization reactions in dilute aqueous solution. 2: Polycondensations

NASA Technical Reports Server (NTRS)

Kolb, Vera; Orgel, Leslie E.

1995-01-01

We have prepared a (P-32)-labeled oligonucleotide probe carrying a ureido (-NH-CO-NH2) function at its 3'-terminus. This labeled oligomer was used to study polycondensations of urea and formaldehyde and of various phenols and formaldehyde in aqueous solution. The formation of formaldehyde copolymers attached to the amido-function of the probe was monitored by gel electrophoresis. Our results are generally in agreement with those obtained using conventional techniques. Our method is suitable for monitoring potentially prebiotic polycondensation reactions involving formaldehyde.

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

PubMed

Hurtado-Gaitán, Elías; Sellés-Marchart, Susana; Martínez-Márquez, Ascensión; Samper-Herrero, Antonio; Bru-Martínez, Roque

2017-03-07

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

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

PubMed

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.

In vivo characterisation of the inflammatory reaction following mesh implantation in transgenic mice models.

PubMed

Fet, N; Alizai, P H; Fragoulis, A; Wruck, C; Pufe, T; Tolba, R H; Neumann, U P; Klinge, U

2014-06-01

Hernia repair with prosthetic meshes represents one of the most common surgical procedures in the field of surgery. This intervention is always associated with an ensuing inflammatory response, angiogenesis and fibrotic encapsulation forming a foreign body granuloma (FBG) around the mesh fibres. Several studies have described this inflammatory reaction by characterising inflammatory cell infiltrate around the FBG after mesh explantation. However, very little is known about the real-time progression of such an inflammatory response. The aim of this study was to investigate the feasibility of monitoring the ongoing inflammatory response to mesh implantation using bioluminescence in vivo. Three luciferase transgenic mice strains (FVB/N-Tg(Vegfr2-luc)-Xen, BALB/C-Tg(NFκB-RE-luc)-Xen and Tg(INS/EpRE-Luc)T20Rbl) were used. Mice were anaesthetized with 2 % isoflurane, and two incisions were made on the left and right sides of the abdomen of the mice. A 1-cm(2) propylene mesh was implanted subcutaneously in the right incision wound of each mouse, and the left wound served as control. Two hundred microliters of D-luciferin was injected into the mice, and bioluminescence measurements were done prior to the surgical intervention and subsequently every 3 days. After mesh explantation, histological analysis was done. Statistical analysis was done using prism GraphPad software. Bioluminescence results revealed different time points of maximum signal for the different mice strains. VEGFR2 gene expression peaked on day 6, NFkB on day 12 and ARE on day 3 post mesh implantation. We also observed much higher bioluminescent signal around the FBG surrounding the mesh as compared to the control wound, with p < 0.05 for all the different mice strains. Our results prove the possibility of monitoring the inflammatory reaction after mesh implantation in vivo using bioluminescence signal release. This provides a novel method of accessing and accurately describing the ongoing inflammatory response over a given period of time.

The effects of anaesthetics on postoperative physiological reactions: a meta-analysis.

PubMed

Wang, Na; Wang, Jinguo; Zhang, Rui; Wang, Fei; Wang, Rui

2015-10-01

This study aimed to systematically investigate the effects of different anaesthetics on postoperative physiological reactions compared with placebo. The literature search was conducted using three databases: PubMed, EMBASE, and the Cochrane Library. Studies published from January 1990 to January 2015 were screened. The language was restricted to English. Heterogeneity was analyzed by the Q test and I(2) statistic. A fixed-effect model was used for homogenous data and a random-effects model for heterogeneous data. The odds ratio (OR) and 95% confidence interval (CI) were calculated to monitor the incidences of overall adverse events, arterial blood pressure, and cardiac abnormalities. Sensitivity analysis was performed to estimate the strength of the meta-analysis, and publication bias was analyzed using Egger's test. A total of 24 articles were included in this meta-analysis. There were 1,810 and 1,806 cases in the anaesthetic group and the placebo group, respectively. The incidence of overall adverse events was significantly lower in the anaesthetic group compared with the placebo group (OR = 0.57; 95% CI, 0.38-0.84). No publication bias was observed, and no inverse estimates were calculated using sensitivity analysis. There was no significant difference for the incidence of arterial blood pressure (OR = 4.62; 95% CI, 0.90-23.70) and cardiac abnormalities (OR = 1.18; 95% CI, 0.53-2.63) between the two groups. Although the incidence of overall adverse events was decreased in the anaesthetic group, it is impossible to determine whether the use of anaesthetics during surgical operation has a protective effect on postoperative physiological reactions. © 2015 Wiley Publishing Asia Pty Ltd.

Chemical analysis of acoustically levitated drops by Raman spectroscopy.

PubMed

Tuckermann, Rudolf; Puskar, Ljiljana; Zavabeti, Mahta; Sekine, Ryo; McNaughton, Don

2009-07-01

An experimental apparatus combining Raman spectroscopy with acoustic levitation, Raman acoustic levitation spectroscopy (RALS), is investigated in the field of physical and chemical analytics. Whereas acoustic levitation enables the contactless handling of microsized samples, Raman spectroscopy offers the advantage of a noninvasive method without complex sample preparation. After carrying out some systematic tests to probe the sensitivity of the technique to drop size, shape, and position, RALS has been successfully applied in monitoring sample dilution and preconcentration, evaporation, crystallization, an acid-base reaction, and analytes in a surface-enhanced Raman spectroscopy colloidal suspension.

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

PubMed

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

2003-10-22

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

MRM assay for quantitation of complement components in human blood plasma - a feasibility study on multiple sclerosis.

PubMed

Rezeli, Melinda; Végvári, Akos; Ottervald, Jan; Olsson, Tomas; Laurell, Thomas; Marko-Varga, György

2011-12-10

As a proof-of-principle study, a multiple reaction monitoring (MRM) assay was developed for quantitation of proteotypic peptides, representing seven plasma proteins associated with inflammation (complement components and C-reactive protein). The assay development and the sample analysis were performed on a linear ion trap mass spectrometer. We were able to quantify 5 of the 7 target proteins in depleted plasma digests with reasonable reproducibility over a 2 orders of magnitude linear range (RSD≤25%). The assay panel was utilized for the analysis of a small multiple sclerosis sample cohort with 10 diseased and 8 control patients. Copyright © 2011 Elsevier B.V. All rights reserved.

Weighing and Body Monitoring among College Women: The Scale Number as an Emotional Barometer

ERIC Educational Resources Information Center

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…

Adverse drug reactions in hospitalized Colombian children.

PubMed

de Las Salas, Roxana; Díaz-Agudelo, Daniela; Burgos-Flórez, Francisco Javier; Vaca, Claudia; Serrano-Meriño, Dolores Vanessa

2016-09-30

The occurrence of adverse drug reactions is an important issue due to the lack of drug safety data in children. To describe the Adverse Drug Reactions in inpatient children under 6 years of age in two general pediatrics wards located in Barranquilla, Colombia. A prospective cohort study based on intensive pharmacovigilance was conducted during six months in order to monitor the emergence of Adverse Drug Reactions in inpatients children under 6 years of age with at least one medication prescribed. The study was conducted in two pediatric wards of two hospitals located in Barranquilla, Colombia. Naranjo´s Algorithm was used to evaluate imputability, the modified Hartwig and Siegel assessment scale to establish severity and the Schumock and Thornton criteria to determine preventability. Of a total of 772 monitored patients, 156 Adverse Drug Reactions were detected on 147 children. The cumulative incidence of Adverse Drug Reactions was 19.0% (147/772); the incidence density was 37.6 Adverse Drug Reactions per 1,000 patients-days (147/3,913). The frequency was higher in children under 2 years of age (12.7%). Emergence of Adverse Drug Reactions was higher in male patients (RR= 1.66; 95% CI= 1.22-2.22, p = 0.001) and in those who used systemic antibiotics (RR= 1.82; 95% CI= 1.17-2.82, p = 0.005). Adverse Drug Reactions are common among hospitalized children and represent an additional burden of morbidity and risk, particularly in those who used several medicines, including antibiotics.

A novel tool for continuous fracture aftercare - Clinical feasibility and first results of a new telemetric gait analysis insole.

PubMed

Braun, Benedikt J; Bushuven, Eva; Hell, Rebecca; Veith, Nils T; Buschbaum, Jan; Holstein, Joerg H; Pohlemann, Tim

2016-02-01

Weight bearing after lower extremity fractures still remains a highly controversial issue. Even in ankle fractures, the most common lower extremity injury no standard aftercare protocol has been established. Average non weight bearing times range from 0 to 7 weeks, with standardised, radiological healing controls at fixed time intervals. Recent literature calls for patient-adapted aftercare protocols based on individual fracture and load scenarios. We show the clinical feasibility and first results of a new, insole embedded gait analysis tool for continuous monitoring of gait, load and activity. Ten patients were monitored with a new, independent gait analysis insole for up to 3 months postoperatively. Strict 20 kg partial weight bearing was ordered for 6 weeks. Overall activity, load spectrum, ground reaction forces, clinical scoring and general health data were recorded and correlated. Statistical analysis with power analysis, t-test and Spearman correlation was performed. Only one patient completely adhered to the set weight bearing limit. Average time in minutes over the limit was 374 min. Based on the parameters load, activity, gait time over 20 kg weight bearing and maximum ground reaction force high and low performers were defined after 3 weeks. Significant difference in time to painless full weight bearing between high and low performers was shown. Correlation analysis revealed a significant correlation between weight bearing and clinical scoring as well as pain (American Orthopaedic Foot and Ankle Society (AOFAS) Score rs=0.74; Olerud-Molander Score rs=0.93; VAS pain rs=-0.95). Early, continuous gait analysis is able to define aftercare performers with significant differences in time to full painless weight bearing where clinical or radiographic controls could not. Patient compliance to standardised weight bearing limits and protocols is low. Highly individual rehabilitation patterns were seen in all patients. Aftercare protocols should be adjusted to real-time patient conditions, rather than fixed intervals and limits. With a real-time measuring device high performers could be identified and influenced towards optimal healing conditions early, while low performers are recognised and missing healing influences could be corrected according to patient condition. Copyright © 2015 Elsevier Ltd. All rights reserved.

A PCR Based Microbial Monitoring Alternative Method of Detection and Identification of Microbes Aboard ISS

NASA Technical Reports Server (NTRS)

Khodadad, Christina; Oubre, Cherie; Castro, Victoria; Flint, Stephanie; Ott, Mark; Roman, Monserrate; Wheeler, Ray; Melendez, Orlando

2017-01-01

Previous research has shown that microorganisms and potential human pathogens have been detected on the International Space Station (ISS) with additional introduction of new microflora occurring with every exchange of crew or addition of equipment and supplies. These microbes are readily transferred between crew and subsystems (i.e. ECLSS, environmental control and life support systems). As this can be detrimental to astronaut health and optimal performance of ISS systems, monitoring of systems such as ECLSS to include identification of microbial contaminants could prevent adverse effects on human health and life support systems. Current monitoring on ISS is laborious and utilizes culture based methods followed by sample return to Earth for complete analysis. Future, long-distance spaceflight missions will require real-time monitoring capabilities that enable efficient and rapid assessments of the microbial environment allowing for expedited decisions and more targeted response to cope with anomalies. Polymerase chain reaction (PCR), a molecular microbial monitoring method was chosen and numerous PCR instruments investigated for their potential to perform in microgravity conditions. Using ISS as a test bed for PCR verification in microgravity will enable NASA to assess whether molecular based microbiological sensors may be components of reliable, closed-loop life support and habitation systems in spacecraft, enhancing infrastructure capabilities through increased efficiency, reliability, and time savings by enabling sample analysis on orbit. NASA selected the Water Monitoring Suite as one of the rapid spaceflight hardware demonstration activities utilizing a streamlined process to minimize the time required to fly experimental flight hardware. The RAZOR EX (BioFire Defense, Salt Lake City, UT) system was part of the water monitoring suite and is a commercial off-the-shelf (COTS) real-time PCR instrument designed for field work. The RAZOR EX was originally designed for Department of Defense (DoD) under a small business innovative research (SBIR) grant and is ruggedized, compact and provides a rapid, sample to answer in less than an hour. PCR assays using a fluorescent probe were optimized and spiked with known concentrations of DNA (Pseudomonas aeruginosa) ranging from 0.002 to 20 ng. PCR reagents were lyophilized and configured in customized pouches and tested for flight readiness. Three types of water were used to rehydrate the reagents and demonstrate the fidelity of the PCR reaction in microgravity. Molecular grade deionized water served as a control while filtered and unfiltered ISS potable water served to test for chemical or biological inhibitors. All three types were compared to parallel ground test results. Nine tests were run on ISS (3 of each water type) and the critical threshold cycle (Ct) was compared to parallel ground tests completed at Kennedy Space Center, FL and Johnson Space Center, TX. All concentrations of Pseudomonas aeruginosa DNA were detected. A comparison of the Ct produced in real time PCR indicated similarity between flight and ground samples. There appeared to be no significant difference between flight or ground PCR reactions or between any of the three water types. This testing demonstrated the ability to perform molecular testing during spaceflight operations with similar sensitivity. It will allow for future ground development of molecular protocols and minimize the need for spaceflight testing. Future testing will include development of additional targets including environmental and health related organisms.

Shock tube measurements of specific reaction rates in branched chain CH4-CO-O2 system

NASA Technical Reports Server (NTRS)

Brabbs, T. A.; Brokaw, R. S.

1974-01-01

Rate constants of two elementary bimolecular reactions involved in the oxidation of methane were determined by monitoring the exponential growth of CO flame band emission behind incident shocks in three suitably chosen gas mixtures.

Chromatographic separation and continuously referenced, on-line monitoring of creatine kinase isoenzymes by use of an immobilized-enzyme microreactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denton, M.S.; Bostick, W.D.; Dinsmore, S.R.

1978-08-01

We describe a new concept in continuously referenced monitoring of the isoenzyme activities of creatine kinase (EC 2.7.3.2) after liquid-chromatographic separation. After separation on a diethylaminoethyl-Sephacel column, the three isoenzymes of creatine kinase undergo a series of coupled enzyme reactions, ultimately resulting in the formation of ultraviolet-detectable NADPH. A major advantage of this detection system is the immobilized-enzyme microreactor (2 x 17 mm), which may be removed and stored refrigerated when not in use. A split-stream configuration allows self-blanking of endogenous ultraviolet-absorbing constituents in authentic sera samples, which would otherwise make definitive diagnosis and quantitation difficult or impossible. This detectionmore » system is applicable to the automated analysis of creatine kinase isoenzymes in the clinical laboratory.« less

Proton mediated control of biochemical reactions with bioelectronic pH modulation

DOE PAGES

Deng, Yingxin; Miyake, Takeo; Keene, Scott; ...

2016-04-07

In Nature, protons (H +) can mediate metabolic process through enzymatic reactions. Examples include glucose oxidation with glucose dehydrogenase to regulate blood glucose level, alcohol dissolution into carboxylic acid through alcohol dehydrogenase, and voltage-regulated H + channels activating bioluminescence in firefly and jellyfish. Artificial devices that control H + currents and H + concentration (pH) are able to actively influence biochemical processes. Here, we demonstrate a biotransducer that monitors and actively regulates pH-responsive enzymatic reactions by monitoring and controlling the flow of H + between PdH x contacts and solution. The present transducer records bistable pH modulation from an “enzymaticmore » flip-flop” circuit that comprises glucose dehydrogenase and alcohol dehydrogenase. Furthermore, the transducer also controls bioluminescence from firefly luciferase by affecting solution pH.« less

Proton mediated control of biochemical reactions with bioelectronic pH modulation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Deng, Yingxin; Miyake, Takeo; Keene, Scott

In Nature, protons (H +) can mediate metabolic process through enzymatic reactions. Examples include glucose oxidation with glucose dehydrogenase to regulate blood glucose level, alcohol dissolution into carboxylic acid through alcohol dehydrogenase, and voltage-regulated H + channels activating bioluminescence in firefly and jellyfish. Artificial devices that control H + currents and H + concentration (pH) are able to actively influence biochemical processes. Here, we demonstrate a biotransducer that monitors and actively regulates pH-responsive enzymatic reactions by monitoring and controlling the flow of H + between PdH x contacts and solution. The present transducer records bistable pH modulation from an “enzymaticmore » flip-flop” circuit that comprises glucose dehydrogenase and alcohol dehydrogenase. Furthermore, the transducer also controls bioluminescence from firefly luciferase by affecting solution pH.« less

Targeted Proteomic Quantification on Quadrupole-Orbitrap Mass Spectrometer*

PubMed Central

Gallien, Sebastien; Duriez, Elodie; Crone, Catharina; Kellmann, Markus; Moehring, Thomas; Domon, Bruno

2012-01-01

There is an immediate need for improved methods to systematically and precisely quantify large sets of peptides in complex biological samples. To date protein quantification in biological samples has been routinely performed on triple quadrupole instruments operated in selected reaction monitoring mode (SRM), and two major challenges remain. Firstly, the number of peptides to be included in one survey experiment needs to be increased to routinely reach several hundreds, and secondly, the degree of selectivity should be improved so as to reliably discriminate the targeted analytes from background interferences. High resolution and accurate mass (HR/AM) analysis on the recently developed Q-Exactive mass spectrometer can potentially address these issues. This instrument presents a unique configuration: it is constituted of an orbitrap mass analyzer equipped with a quadrupole mass filter as the front-end for precursor ion mass selection. This configuration enables new quantitative methods based on HR/AM measurements, including targeted analysis in MS mode (single ion monitoring) and in MS/MS mode (parallel reaction monitoring). The ability of the quadrupole to select a restricted m/z range allows one to overcome the dynamic range limitations associated with trapping devices, and the MS/MS mode provides an additional stage of selectivity. When applied to targeted protein quantification in urine samples and benchmarked with the reference SRM technique, the quadrupole-orbitrap instrument exhibits similar or better performance in terms of selectivity, dynamic range, and sensitivity. This high performance is further enhanced by leveraging the multiplexing capability of the instrument to design novel acquisition methods and apply them to large targeted proteomic studies for the first time, as demonstrated on 770 tryptic yeast peptides analyzed in one 60-min experiment. The increased quality of quadrupole-orbitrap data has the potential to improve existing protein quantification methods in complex samples and address the pressing demand of systems biology or biomarker evaluation studies. PMID:22962056

Rapid monitoring of intermediate states and mass balance of nitrogen during denitrification by means of cavity enhanced Raman multi-gas sensing.

PubMed

Keiner, Robert; Herrmann, Martina; Küsel, Kirsten; Popp, Jürgen; Frosch, Torsten

2015-03-15

The comprehensive investigation of changes in N cycling has been challenging so far due to difficulties with measuring gases such as N2 and N2O simultaneously. In this study we introduce cavity enhanced Raman gas spectroscopy as a new analytical methodology for tracing the stepwise reduction of (15)N-labelled nitrate by the denitrifying bacteria Pseudomonas stutzeri. The unique capabilities of Raman multi-gas analysis enabled real-time, continuous, and non-consumptive quantification of the relevant gases ((14)N2, (14)N2O, O2, and CO2) and to trace the fate of (15)N-labeled nitrate substrate ((15)N2, (15)N2O) added to a P. stutzeri culture with one single measurement. Using this new methodology, we could quantify the kinetics of the formation and degradation for all gaseous compounds (educts and products) and thus study the reaction orders. The gas quantification was complemented with the analysis of nitrate and nitrite concentrations for the online monitoring of the total nitrogen element budget. The simultaneous quantification of all gases also enabled the contactless and sterile online acquisition of the pH changes in the P. stutzeri culture by the stoichiometry of the redox reactions during denitrification and the CO2-bicarbonate equilibrium. Continuous pH monitoring - without the need to insert an electrode into solution - elucidated e.g. an increase in the slope of the pH value coinciding with an accumulation of nitrite, which in turn led to a temporary accumulation of N2O, due to an inhibition of nitrous oxide reductase. Cavity enhanced Raman gas spectroscopy has a high potential for the assessment of denitrification processes and can contribute substantially to our understanding of nitrogen cycling in both natural and agricultural systems. Copyright © 2015 Elsevier B.V. All rights reserved.

Advanced oxidation of acridine orange by aqueous alkaline iodine.

PubMed

Azmat, Rafia; Qamar, Noshab; Naz, Raheela; Khursheed, Anum

2016-11-01

The advanced oxidation process is certainly used for the dye waste water treatment. In this continuation a new advanced oxidation via aqueous alkaline iodine was developed for the oxidation of acridine orange (AO) {3, 6 -bis (dimethylamino) acridine zinc chloride double salt}. Oxidation Kinetics of AO by alkaline solution of iodine was investigated spectrophotometrically at λ max 491 nm. The reaction was monitored at various operational parameters like several concentrations of dye and iodine, pH, salt electrolyte and temperature. The initial steps of oxidation kinetics followed fractional order reaction with respect to the dye while depend upon the incremental amount of iodine to certain extent whereas maximum oxidation of AO was achieved at high pH. Decline in the reaction rate in the presence of salt electrolyte suggested the presence of oppositely charged species in the rate determining step. Kinetic data revealed that the de-colorization mechanism involves triodate (I 3 - ) species, instead of hypoidate (OI - ) and hypiodous acid (HOI), in alkaline medium during the photo-excitation of hydrolyzed AO. Alleviated concentration of alkali result in decreasing of rate of reaction, clearly indicate that the iodine species are active oxidizing species instead of OH radical. Activation parameters at elevated temperatures were determined which revealed that highly solvated state of dye complex existed into solution. Reaction mixture was subjected to UV/Visible and GC mass spectrum analysis that proves the secondary consecutive reaction was operative in rate determining step and finally dye complex end into smaller fragments.

[Rapid screening the alkaloids of poppy shell in hot pot condiment, beef noodle soup and seasoning by direct analysis in real time-tandem mass spectrometry].

PubMed

Zhang, Baile; Gao, Lihong; Xie, Yingshuang; Zhou, Wei; Chen, Xiaofeng; Lei, Chunni; Zhang, Huan

2017-07-08

A direct analysis in real time tandem mass spectrometry (DART-MS/MS) method was established for quickly screening five illegally added alkaloids of poppy shell from the hot pot condiment, beef noodle soup and seasoning. The samples were extracted and purified by acetonitrile, and then injected under the conditions of ionization temperature of 300℃, grid electrode voltage of 150 V and sampling rate of 0.8 mm/s using DART in the positive ion mode. The determination was conducted by tandem mass spectrometry in positive ESI mode under multiple reaction monitoring (MRM) mode. The method is simple and rapid, and can meet the requirement of rapid screening and analysis of large quantities of samples.

Graphene Nanoprobes for Real-Time Monitoring of Isothermal Nucleic Acid Amplification.

PubMed

Li, Fan; Liu, Xiaoguo; Zhao, Bin; Yan, Juan; Li, Qian; Aldalbahi, Ali; Shi, Jiye; Song, Shiping; Fan, Chunhai; Wang, Lihua

2017-05-10

Isothermal amplification is an efficient way to amplify DNA with high accuracy; however, the real-time monitoring for quantification analysis mostly relied on expensive and precisely designed probes. In the present study, a graphene oxide (GO)-based nanoprobe was used to real-time monitor the isothermal amplification process. The interaction between GO and different DNA structures was systematically investigated, including single-stranded DNA (ssDNA), double-stranded DNA (dsDNA), DNA 3-helix, and long rolling circle amplification (RCA) and hybridization chain reaction (HCR) products, which existed in one-, two-, and three-dimensional structures. It was found that the high rigid structures exhibited much lower affinity with GO than soft ssDNA, and generally the rigidity was dependent on the length of targets and the hybridization position with probe DNA. On the basis of these results, we successfully monitored HCR amplification process, RCA process, and the enzyme restriction of RCA products with GO nanoprobe; other applications including the detection of the assembly/disassembly of DNA 3-helix structures were also performed. Compared to the widely used end-point detection methods, the GO-based sensing platform is simple, sensitive, cost-effective, and especially in a real-time monitoring mode. We believe such studies can provide comprehensive understandings and evocation on design of GO-based biosensors for broad application in various fields.

Adduct ion-targeted qualitative and quantitative analysis of polyoxypregnanes by ultra-high pressure liquid chromatography coupled with triple quadrupole mass spectrometry.

PubMed

Wu, Xu; Zhu, Lin; Ma, Jiang; Ye, Yang; Lin, Ge

2017-10-25

Polyoxypregnane and its glycosides (POPs) are frequently present in plants of Asclepiadaceae family, and have a variety of biological activities. There is a great need to comprehensively profile these phytochemicals and to quantify them for monitoring their contents in the herbs and the biological samples. However, POPs undergo extensive adduct ion formation in ESI-MS, which has posed a challenge for qualitative and quantitative analysis of POPs. In the present study, we took the advantage of such extensive adduct ion formation to investigate the suitability of adduct ion-targeted analysis of POPs. For the qualitative analysis, we firstly demonstrated that the sodium and ammonium adduct ion-targeted product ion scans (PIS) provided adequate MS/MS fragmentations for structural characterization of POPs. Aided with precursor ion (PI) scans, which showed high selectivity and sensitivity and improved peak assignment confidence in conjunction with full scan (FS), the informative adduct ion-targeted PIS enabled rapid POPs profiling. For the quantification, we used formic acid rather than ammonium acetate as an additive in the mobile phase to avoid simultaneous formation of sodium and ammonium adduct ions, and greatly improved reproducibility of MS response of POPs. By monitoring the solely formed sodium adduct ions [M+Na] + , a method for simultaneous quantification of 25 POPs in the dynamic multiple reaction monitoring mode was then developed and validated. Finally, the aforementioned methods were applied to qualitative and quantitative analysis of POPs in the extract of a traditional Chinses medicinal herb, Marsdenia tenacissima (Roxb.) Wight et Arn., and in the plasma obtained from the rats treated with this herb. The results demonstrated that adduct ion formation could be optimized for the qualitative and quantitative analysis of POPs, and our developed PI/FS-PIS scanning and sole [M+Na] + ion monitoring significantly improved the analysis of POPs in both herbal and biological samples. This study also provides implications for the analysis of other compounds which undergo extensive adduct ion formation in ESI-MS. Copyright © 2017 Elsevier B.V. All rights reserved.

Synchronous monitoring of muscle dynamics and electromyogram

NASA Astrophysics Data System (ADS)

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.

Simultaneous probing of bulk liquid phase and catalytic gas-liquid-solid interface under working conditions using attenuated total reflection infrared spectroscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Meemken, Fabian; Müller, Philipp; Hungerbühler, Konrad

Design and performance of a reactor set-up for attenuated total reflection infrared (ATR-IR) spectroscopy suitable for simultaneous reaction monitoring of bulk liquid and catalytic solid-liquid-gas interfaces under working conditions are presented. As advancement of in situ spectroscopy an operando methodology for gas-liquid-solid reaction monitoring was developed that simultaneously combines catalytic activity and molecular level detection at the catalytically active site of the same sample. Semi-batch reactor conditions are achieved with the analytical set-up by implementing the ATR-IR flow-through cell in a recycle reactor system and integrating a specifically designed gas feeding system coupled with a bubble trap. By the usemore » of only one spectrometer the design of the new ATR-IR reactor cell allows for simultaneous detection of the bulk liquid and the catalytic interface during the working reaction. Holding two internal reflection elements (IRE) the sample compartments of the horizontally movable cell are consecutively flushed with reaction solution and pneumatically actuated, rapid switching of the cell (<1 s) enables to quasi simultaneously follow the heterogeneously catalysed reaction at the catalytic interface on a catalyst-coated IRE and in the bulk liquid on a blank IRE. For a complex heterogeneous reaction, the asymmetric hydrogenation of 2,2,2-trifluoroacetophenone on chirally modified Pt catalyst the elucidation of catalytic activity/enantioselectivity coupled with simultaneous monitoring of the catalytic solid-liquid-gas interface is shown. Both catalytic activity and enantioselectivity are strongly dependent on the experimental conditions. The opportunity to gain improved understanding by coupling measurements of catalytic performance and spectroscopic detection is presented. In addition, the applicability of modulation excitation spectroscopy and phase-sensitive detection are demonstrated.« less

Mass spectrometric real-time monitoring of an enzymatic phosphorylation assay using internal standards and data-handling freeware.

PubMed

Krappmann, Michael; de Boer, Arjen R; Kool, Daniël R W; Irth, Hubertus; Letzel, Thomas

2016-04-30

Continuous-flow reaction detection systems (monitoring enzymatic reactions with mass spectrometry (MS)) lack quantitative values so far. Therefore, two independent internal standards (IS) are implemented in a way that the online system stability can be observed, quantitative conversion values for substrate and product can be obtained and they can be used as mass calibration standards for high MS accuracy. An application previously developed for the MS detection of peptide phosphorylation by cAMP-dependent protein kinase A (PKA) (De Boer et al., Anal. Bioanal. Chem. 2005, 381, 647-655) was transferred to a continuous-flow reaction detection system. This enzymatic reaction, involving enzyme activation as well as the transfer of a phosphate group from ATP to a peptide substrate, was used to prove the compatibility of a quantitative enzymatic assay in a continuous-flow real-time system (connected to MS). Moreover (using internal standards), the critical parameter reaction temperature (including solution density variations depending on temperature) was studied in the continuous-flow mixing system. Furthermore, two substrates (malantide and kemptide), two enzyme types (catalytic subunit of PKA and complete PKA) and one inhibitor were tested to determine system robustness and long-term availability. Even spraying solutions that contained significant amount of MS contaminants (e.g. the polluted catalytic subunit) resulted in quantifiable MS signal intensities. Subsequent recalculations using the internal standards led to results representing the power of this application. The presented methodology and the data evaluation with available Achroma freeware enable the direct coupling of biochemical assays with quantitative MS detection. Monitoring changes such as temperature, reaction time, inhibition, or compound concentrations can be observed quantitatively and thus enzymatic activity can be calculated. Copyright © 2016 John Wiley & Sons, Ltd.

A liquid chromatography-mass spectrometric method for the determination of oak moss allergens atranol and chloroatranol in perfumes.

PubMed

Bossi, Rossana; Rastogi, Suresh C; Bernard, Guillaume; Gimenez-Arnau, Elena; Johansen, Jeanne D; Lepoittevin, Jean-Pierre; Menné, Torkil

2004-05-01

This paper describes a validated liquid chromatographic-tandem mass spectrometric method for quantitative analysis of the potential oak moss allergens atranol and chloroatranol in perfumes and similar products. The method employs LC-MS-MS with electrospray ionization (ESI) in negative mode. The compounds are analysed by selective reaction monitoring (SRM) of 2 or 3 ions for each compound in order to obtain high selectivity and sensitivity. The method has been validated for the following parameters: linearity; repeatability; recovery; limit of detection; and limit of quantification. The limits of detection, 5.0 ng/mL and 2.4 ng/mL, respectively, for atranol and chloroatranol, achieved by this method allowed identification of these compounds at concentrations below those causing allergic skin reactions in oak-moss-sensitive patients. The recovery of chloratranol from spiked perfumes was 96+/-4%. Low recoveries (49+/-5%) were observed for atranol in spiked perfumes, indicating ion suppression caused by matrix components. The method has been applied to the analysis of 10 randomly selected perfumes and similar products.

Exploring the energy landscape for Q(A)(-) to Q(B) electron transfer in bacterial photosynthetic reaction centers: effect of substrate position and tail length on the conformational gating step.

PubMed

Xu, Qiang; Baciou, Laura; Sebban, Pierre; Gunner, M R

2002-08-06

The ability to initiate reactions with a flash of light and to monitor reactions over a wide temperature range allows detailed analysis of reaction mechanisms in photosynthetic reaction centers (RCs) of purple bacteria. In this protein, the electron transfer from the reduced primary quinone (Q(A)(-)) to the secondary quinone (Q(B)) is rate-limited by conformational changes rather than electron tunneling. Q(B) movement from a distal to a proximal site has been proposed to be the rate-limiting change. The importance of quinone motion was examined by shortening the Q(B) tail from 50 to 5 carbons. No change in rate was found from 100 to 300 K. The temperature dependence of the rate was also measured in three L209 proline mutants. Under conditions where Q(B) is in the distal site in wild-type RCs, it is trapped in the proximal site in the Tyr L209 mutant [Kuglstatter, A., et al. (2001) Biochemistry 40, 4253-4260]. The electron transfer slows at low temperature for all three mutants as it does in wild-type protein, indicating that conformational changes still limit the reaction rate. Thus, Q(B) movement is unlikely to be the sole, rate-limiting conformational gating step. The temperature dependence of the reaction in the L209 mutants differs somewhat from wild-type RCs. Entropy-enthalpy compensation reduces the difference in rates and free energy changes at room temperature.

Ocular Toxoplasmosis: Therapy-Related Adverse Drug Reactions and Their Management.

PubMed

Helfenstein, M; Zweifel, S; Barthelmes, D; Meier, F; Fehr, J; Böni, C

2017-04-01

Background There are different treatment options for ocular toxoplasmosis (OT). "Classic" therapy consists of pyrimethamine, sulfadiazine and folinic acid combined with systemic steroids and is still widely used. However, potentially severe side effects of this therapy have been reported. The aim of this retrospective study was to evaluate the incidence and types of adverse drug reactions in patients treated for OT. Clinical management of each adverse drug reaction was assessed. Patients and Methods In this retrospective analysis, we reviewed data of patients with OT, who were consecutively examined between December 2011 and December 2015 at the Department of Ophthalmology, University Hospital Zurich. Results In total, 49 patients had at least one episode of active OT. In 54 (83.0 %) of 65 treated episodes, the classic regimen was used. Of the 37 patients who received classic treatment, 9 (24.3 %) developed at least one adverse drug reaction which led to drug discontinuation, including elevated creatinine (5.4 %), elevated liver enzymes (5.4 %), vomiting (5.4 %), rash (5.4 %) and facial swelling (2.7 %). In 5 patients, treatment was switched to another drug, while in the other 4 patients, therapy was stopped. In these 9 patients, inflammation was well controlled 8 weeks after onset of therapy. No patient suffered from severe side effects, such as potentially life-threatening allergic reactions or pancytopenia. Conclusions In OT patients who were treated with classic therapy, adverse drug reactions are common. Therefore, clinical and laboratory monitoring is mandatory. Adverse drug reactions may require interdisciplinary management. Georg Thieme Verlag KG Stuttgart · New York.

Serious games for elderly continuous monitoring.

PubMed

Lemus-Zúñiga, Lenin-G; Navarro-Pardo, Esperanza; Moret-Tatay, Carmen; Pocinho, Ricardo

2015-01-01

Information technology (IT) and serious games allow older population to remain independent for longer. Hence, when designing technology for this population, developmental changes, such as attention and/or perception, should be considered. For instance, a crucial developmental change has been related to cognitive speed in terms of reaction time (RT). However, this variable presents a skewed distribution that difficult data analysis. An alternative strategy is to characterize the data to an ex-Gaussian function. Furthermore, this procedure provides different parameters that have been related to underlying cognitive processes in the literature. Another issue to be considered is the optimal data recording, storing and processing. For that purpose mobile devices (smart phones and tablets) are a good option for targeting serious games where valuable information can be stored (time spent in the application, reaction time, frequency of use, and a long etcetera). The data stored inside the smartphones and tablets can be sent to a central computer (cloud storage) in order to store the data collected to not only fill the distribution of reaction times to mathematical functions, but also to estimate parameters which may reflect cognitive processes underlying language, aging, and decisional process.

The 13C(n,α0)10Be cross section at 14.3 MeV and 17 MeV neutron energy

NASA Astrophysics Data System (ADS)

Kavrigin, P.; Belloni, F.; Frais-Koelbl, H.; Griesmayer, E.; Plompen, A. J. M.; Schillebeeckx, P.; Weiss, C.

2017-09-01

At nuclear fusion reactors, CVD diamond detectors are considered an advantageous solution for neutron flux monitoring. For such applications the knowledge of the cross section of neutron-induced nuclear reactions on natural carbon are of high importance. Especially the (n,α0) reactions, yielding the highest energy reaction products, are of relevance as they can be clearly distinguished in the spectrum. The 13C(n,α0)10Be cross section was measured relative to 12C(n,α0)9Be at the Van de Graaff facility of EC-JRC Geel, Belgium, at 14.3 MeV and 17.0 MeV neutron energies. The measurement was performed with an sCVD (single-crystal Chemical Vapor Deposition) diamond detector, where the detector material acted simultaneously as sample and as sensor. A novel data analysis technique, based on pulse-shape discrimination, allowed an efficient reduction of background events. The results of the measurement are presented and compared to previously published values for this cross-section.

Optical bio-sniffer for ethanol vapor using an oxygen-sensitive optical fiber.

PubMed

Mitsubayashi, Kohji; Kon, Takuo; Hashimoto, Yuki

2003-11-30

An optical bio-sniffer for ethanol was constructed by immobilizing alcohol oxidase (AOD) onto a tip of a fiber optic oxygen sensor with a tube-ring, using an oxygen sensitive ruthenium organic complex (excitation, 470 nm; fluorescent, 600 nm). A reaction unit for circulating buffer solution was applied to the tip of the device. After the experiment in the liquid phase, the sniffer-device was applied for gas analysis using a gas flow measurement system with a gas generator. The optical device was applied to detect the oxygen consumption induced by AOD enzymatic reaction with alcohol application. The sensor in the liquid phase was used to measure ethanol solution from 0.50 to 9.09 mmol/l. Then, the bio-sniffer was calibrated against ethanol vapor from 0.71 to 51.49 ppm with good gas-selectivity based on the AOD substrate specificity. The bio-sniffer with the reaction unit was also used to monitor the concentration change of gaseous ethanol by rinsing and cleaning the fiber tip and the enzyme membrane with buffer solution.

Identification of reaction products from reactions of free chlorine with the lipid-regulator gemfibrozil.

PubMed

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.

Multiplexed detection of anthrax-related toxin genes.

PubMed

Moser, Michael J; Christensen, Deanna R; Norwood, David; Prudent, James R

2006-02-01

Simultaneous analysis of three targets in three colors on any real-time polymerase chain reaction (PCR) instrument would increase the flexibility of real-time PCR. For the detection of Bacillus strains that can cause inhalation anthrax-related illness, this ability would be valuable because two plasmids confer virulence, and internal positive controls are needed to monitor the testing in cases lacking target-specific signals. Using a real-time PCR platform called MultiCode-RTx, multiple assays were developed that specifically monitor the presence of Bacillus anthracis-specific virulence plasmid-associated genes. In particular for use on LightCycler-1, two triplex RTx systems demonstrated high sensitivity with limits of detection nearing single-copy levels for both plasmids. Specificity was established using a combination of Ct values and correct amplicon melting temperatures. All reactions were further verified by detection of an internal positive control. For these two triplex RTx assays, the analytical detection limit was one to nine plasmid copy equivalents, 100% analytical specificity with a 95% confidence interval (CI) of 9%, and 100% analytical sensitivity with a CI of 2%. Although further testing using clinical or environmental samples will be required to assess diagnostic sensitivity and specificity, the RTx platform achieves similar results to those of probe-based real-time systems.

Real-Time Optical Monitoring of Flow Kinetics and Gas Phase Reactions Under High-Pressure OMCVD Conditions

NASA Technical Reports Server (NTRS)

Dietz, N.; McCall, S.; Bachmann, K. J.

2001-01-01

This contribution addresses the real-time optical characterization of gas flow and gas phase reactions as they play a crucial role for chemical vapor phase depositions utilizing elevated and high pressure chemical vapor deposition (HPCVD) conditions. The objectives of these experiments are to validate on the basis of results on real-time optical diagnostics process models simulation codes, and provide input parameter sets needed for analysis and control of chemical vapor deposition at elevated pressures. Access to microgravity is required to retain high pressure conditions of laminar flow, which is essential for successful acquisition and interpretation of the optical data. In this contribution, we describe the design and construction of the HPCVD system, which include access ports for various optical methods of real-time process monitoring and to analyze the initial stages of heteroepitaxy and steady-state growth in the different pressure ranges. To analyze the onset of turbulence, provisions are made for implementation of experimental methods for in-situ characterization of the nature of flow. This knowledge will be the basis for the design definition of experiments under microgravity, where gas flow conditions, gas phase and surface chemistry, might be analyzed by remote controlled real-time diagnostics tools, developed in this research project.

In-situ biochemical remediation of chlorinated organic compounds present as DNAPL using vitamin B12 and reduced titanium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lesage, S.; Sorel, D.; Cherry, J.A.

1995-12-31

The feasibility of using a biochemical treatment for the cleanup of DNAPL solvents in the saturated zone was tested using an in-situ large vertical column. Laboratory column studies have shown that a mixture of vitamin B12 and titanium citrate pumped through a column containing 100 {mu}L of tetrachloroethene can completely dissolve and degrade the residual to ethene in a few days. A vertical test column, 80 cm in diameter was installed within a sheet-pile cell isolating a portion of aquifer at CFB Borden. An equimolar mixture of tetrachloroethene and 1,1,1-trichloroethane was injected below the water table to form a residualmore » DNAPL. The injection withdrawal system was operated in an upward flow mode over a 2 m height. In order for the reaction to be proceed, the in-situ pH must be greater than 7 and the Eh lower than -480 mV. The redox of the aquifer and the formation of reaction products was monitored on site, through 8 side pods equipped with stainless steel tubing terminated with 40 {mu}m porous cups, installed at different heights in the test column. The volatile products at the withdrawal well were monitored on-line by dynamic headspace analysis/gas chromatography.« less

Post-translational quantitation by SRM/MRM: applications in cardiology.

PubMed

Gianazza, Erica; Banfi, Cristina

2018-06-04

Post-translational modifications (PTMs) have an important role in the regulation of protein function, localization and interaction with other molecules. PTMs apply a dynamic control of proteins both in physiological and pathological conditions. The study of disease-specific PTMs allows identifying potential biomarkers and developing effective drugs. Enrichment techniques combined with high-resolution MS/MS analysis provide attractive results on PTMs characterization. Selected reaction monitoring/multiple reaction monitoring (SRM/MRM) is a powerful targeted assay for the quantitation and validation of PTMs in complex biological samples. Areas covered: The most frequent PTMs are described in terms of biological role and analytical methods commonly used to detect them. The applications of SRM/MRM for the absolute quantitation of PTMs are reported and a specific section is focused on PTMs detection in proteins that are involved in cardiovascular system and heart diseases. Expert commentary: PTMs characterization in relation to disease pathology is still in progress, but targeted proteomics by LC-MS/MS has significantly upgraded the knowledge in the last years. Advances in enrichment strategies and software tools will facilitate the interpretation of high PTMs complexity. Promising studies confirm the great potentiality of SRM/MRM to study PTMs in cardiovascular field and PTMomics could be very useful in a clinical perspective.

Mass spectrometry-based targeted quantitative proteomics: achieving sensitive and reproducible detection of proteins.

PubMed

Boja, Emily S; Rodriguez, Henry

2012-04-01

Traditional shotgun proteomics used to detect a mixture of hundreds to thousands of proteins through mass spectrometric analysis, has been the standard approach in research to profile protein content in a biological sample which could lead to the discovery of new (and all) protein candidates with diagnostic, prognostic, and therapeutic values. In practice, this approach requires significant resources and time, and does not necessarily represent the goal of the researcher who would rather study a subset of such discovered proteins (including their variations or posttranslational modifications) under different biological conditions. In this context, targeted proteomics is playing an increasingly important role in the accurate measurement of protein targets in biological samples in the hope of elucidating the molecular mechanism of cellular function via the understanding of intricate protein networks and pathways. One such (targeted) approach, selected reaction monitoring (or multiple reaction monitoring) mass spectrometry (MRM-MS), offers the capability of measuring multiple proteins with higher sensitivity and throughput than shotgun proteomics. Developing and validating MRM-MS-based assays, however, is an extensive and iterative process, requiring a coordinated and collaborative effort by the scientific community through the sharing of publicly accessible data and datasets, bioinformatic tools, standard operating procedures, and well characterized reagents. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Mining Missing Membrane Proteins by High-pH Reverse-Phase StageTip Fractionation and Multiple Reaction Monitoring Mass Spectrometry.

PubMed

Kitata, Reta Birhanu; Dimayacyac-Esleta, Baby Rorielyn T; Choong, Wai-Kok; Tsai, Chia-Feng; Lin, Tai-Du; Tsou, Chih-Chiang; Weng, Shao-Hsing; Chen, Yi-Ju; Yang, Pan-Chyr; Arco, Susan D; Nesvizhskii, Alexey I; Sung, Ting-Yi; Chen, Yu-Ju

2015-09-04

Despite significant efforts in the past decade toward complete mapping of the human proteome, 3564 proteins (neXtProt, 09-2014) are still "missing proteins". Over one-third of these missing proteins are annotated as membrane proteins, owing to their relatively challenging accessibility with standard shotgun proteomics. Using nonsmall cell lung cancer (NSCLC) as a model study, we aim to mine missing proteins from disease-associated membrane proteome, which may be still largely under-represented. To increase identification coverage, we employed Hp-RP StageTip prefractionation of membrane-enriched samples from 11 NSCLC cell lines. Analysis of membrane samples from 20 pairs of tumor and adjacent normal lung tissue was incorporated to include physiologically expressed membrane proteins. Using multiple search engines (X!Tandem, Comet, and Mascot) and stringent evaluation of FDR (MAYU and PeptideShaker), we identified 7702 proteins (66% membrane proteins) and 178 missing proteins (74 membrane proteins) with PSM-, peptide-, and protein-level FDR of 1%. Through multiple reaction monitoring using synthetic peptides, we provided additional evidence of eight missing proteins including seven with transmembrane helix domains. This study demonstrates that mining missing proteins focused on cancer membrane subproteome can greatly contribute to map the whole human proteome. All data were deposited into ProteomeXchange with the identifier PXD002224.

Compatibility studies of acyclovir and lactose in physical mixtures and commercial tablets.

PubMed

Monajjemzadeh, Farnaz; Hassanzadeh, Davoud; Valizadeh, Hadi; Siahi-Shadbad, Mohammad R; Mojarrad, Javid Shahbazi; Robertson, Thomas A; Roberts, Michael S

2009-11-01

This study documents drug-excipient incompatibility studies of acyclovir in physical mixtures with lactose and in different tablet brands. Differential scanning calorimetry (DSC) was initially used to assess compatibility of mixtures. The Fourier-transform infrared (FTIR) spectrum was also compared with the spectra of pure drug and excipient. Although DSC results indicated incompatibility with lactose, FTIR spectra were mostly unmodified due to overlapping peaks. Samples of isothermally stressed physical mixture were stored at 95 degrees C for 24 h. The residual drug was monitored using a validated high-performance liquid chromatography (HPLC) assay and data fitting to solid-state kinetic models was performed. The drug loss kinetics followed a diffusion model. The aqueous mixture of drug and excipient was heated in order to prepare an adduct mixture. HPLC analysis revealed one extra peak that was fractionated and subsequently injected into the liquid chromatography-mass spectrometry/mass spectrometry (LC-MS/MS) system. The MRM (Multiple Reaction Monitoring) chromatograms characterized the peak with molecular mass corresponding to an acyclovir-lactose Maillard reaction product. The presence of lactose in commercial tablets was checked using a new TLC method. Overall, the incompatibility of acyclovir with lactose was successfully evaluated using a combination of thermal methods and LC-MS/MS.

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

PubMed

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 (<5.46%), inter-day precision (<6.36%), and recovery (86.42-112.48%). The results indicate that the approach of combining IL-DLLME with UPLC-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.

What is in a beer? Proteomic characterization and relative quantification of hordein (gluten) in beer.

PubMed

Colgrave, Michelle L; Goswami, Hareshwar; Howitt, Crispin A; Tanner, Gregory J

2012-01-01

The suite of prolamin proteins present in barley flour was characterized in this study, in which we provide spectral evidence for 3 previously characterized prolamins, 8 prolamins with only transcript evidence, and 19 genome-derived predicted prolamins. An additional 9 prolamins were identified by searching the complete spectral set against an unannotated translated EST database. Analyses of wort, the liquid extracted from the mashing process during beer production, and beer were undertaken and a similar suite of prolamins were identified. We have demonstrated by using tandem mass spectrometry that hordeins are indeed present in beer despite speculation to the contrary. Multiple reaction monitoring (MRM) mass spectrometry was used for the rapid analyses of hordein in barley (Hordeum vulgare L.) beer. A selection of international beers were analyzed and compared to the results obtained with hordein deletion beers. The hordein deletion beers were brewed from grains carrying mutations that prevented the accumulation of either B-hordeins (Risø 56) or C-hordeins (Risø 1508). No intact C-hordeins were detected in beer, although fragments of C-hordeins were present in wort. Multiple reaction monitoring analysis of non-barley based gluten (hordein)-free beers targeting the major hordein protein families was performed and confirmed the absence of hordein in several gluten-free commercial beers.

Quantitation of lysergic acid diethylamide in urine using atmospheric pressure matrix-assisted laser desorption/ionization ion trap mass spectrometry.

PubMed

Cui, Meng; McCooeye, Margaret A; Fraser, Catharine; Mester, Zoltán

2004-12-01

A quantitative method was developed for analysis of lysergic acid diethylamide (LSD) in urine using atmospheric pressure matrix-assisted laser desorption/ionization ion trap mass spectrometry (AP MALDI-ITMS). Following solid-phase extraction of LSD from urine samples, extracts were analyzed by AP MALDI-ITMS. The identity of LSD was confirmed by fragmentation of the [M + H](+) ion using tandem mass spectrometry. The quantification of LSD was achieved using stable-isotope-labeled LSD (LSD-d(3)) as the internal standard. The [M + H](+) ion fragmented to produce a dominant fragment ion, which was used for a selected reaction monitoring (SRM) method for quantitative analysis of LSD. SRM was compared with selected ion monitoring and produced a wider linear range and lower limit of quantification. For SRM analysis of samples of LSD spiked in urine, the calibration curve was linear in the range of 1-100 ng/mL with a coefficient of determination, r(2), of 0.9917. This assay was used to determine LSD in urine samples and the AP MALDI-MS results were comparable to the HPLC/ ESI-MS results.

Monitoring of soluble starch hydrolysis induced by α-amylase from Aspergillus oryzae using ultrasonic spectroscopy

NASA Astrophysics Data System (ADS)

Sierra, Carlos; Resa, Pablo; Buckin, Vitaly; Elvira, Luis

2012-05-01

The online monitoring of enzymatic starch hydrolysis is an important issue for several industrial sectors, mainly in the alimentary industry. Ultrasonic non-invasive methods based on the detection of wave velocity and amplitude changes can be used to study this enzymatic reaction. These wave propagating changes are result of physicalchemical modifications produced in the media by the starch hydrolysis. In this work the starch hydrolysis induced by the enzyme α-amylase from Aspergillus oryzae is studied. This biochemical reaction has been monitored using a high-resolution ultrasonic spectroscopy (HR-US) which is non-invasive and nondestructive. The measured time profiles o of ultrasonic velocity are explained in terms of the starch hydrolysis and the subsequent production of oligosaccharides as a consequence of the enzymatic action. The obtained results have been compared to a conventional off-line technique used in biochemistry, the iodine-starch reaction, a spectrophotometric method to quantify the amount of starch remaining in the medium. The combination of these two types of measurement provides more complete information about the biochemical processes occurred during hydrolysis.

Post Launch Monitoring of food products: what can be learned from pharmacovigilance.

PubMed

van Puijenbroek, E P; Hepburn, P A; Herd, T M; van Grootheest, A C

2007-03-01

Post Launch Monitoring (PLM) is one of the new approaches that are used in assessing the safety of novel foods or ingredients. It shares a close resemblance with procedures applied in the field of medicines, where Post Marketing Surveillance (PMS) has been carried out since the beginning of the 1960s. For this reason, Unilever and the Netherlands Pharmacovigilance Centre Lareb, maintaining the national reporting scheme in the Netherlands for adverse drug reactions, have been working together to optimize the Unilever's Post Launch Monitoring service. As a result of this cooperation a practical model for conducting PLM for food products has been developed. This model is also applicable for consumer products in general. The system allows for coding and assessing reports and the early detection of 'signals' of unintended health reactions. The methodological issues surrounding reporting of possible health reactions and practical issues surrounding coding and assessment of the reports that were encountered in the first period of this partnership are discussed. In addition, similarities and differences concerning PMS and PLM are described.

Basic design of MRM assays for peptide quantification.

PubMed

James, Andrew; Jorgensen, Claus

2010-01-01

With the recent availability and accessibility of mass spectrometry for basic and clinical research, the requirement for stable, sensitive, and reproducible assays to specifically detect proteins of interest has increased. Multiple reaction monitoring (MRM) or selective reaction monitoring (SRM) is a highly selective, sensitive, and robust assay to monitor the presence and amount of biomolecules. Until recently, MRM was typically used for the detection of drugs and other biomolecules from body fluids. With increased focus on biomarkers and systems biology approaches, researchers in the proteomics field have taken advantage of this approach. In this chapter, we will introduce the reader to the basic principle of designing and optimizing an MRM workflow. We provide examples of MRM workflows for standard proteomic samples and provide suggestions for the reader who is interested in using MRM for quantification.

Photocatalytic degradation of paracetamol: intermediates and total reaction mechanism.

PubMed

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.

Mechanism of chemical activation of sodium chloride in the presence of amino acids.

PubMed

Rahn, Anja K K; Yaylayan, Varoujan A

2015-01-01

Sodium chloride has been shown to promote chlorination of glycerol during thermal processing. However, the detailed mechanism of this reaction is not well understood. Preliminary experiments have indicated that the reaction mixture should contain an amino acid and it should be dissolved thoroughly in water in order to induce chlorination. These observations are consistent with the process of dissociation of sodium chloride and its re-association with amino acid and eventual formation of the chlorinating agent in the form of the hydrochloride salt. Release of HCl from this salt can be manifested in chlorination and hydrolytic reactions occurring during thermal processing. The generation of HCl at room temperature from a mixture of sodium chloride and glycine was confirmed through spectrophotometric monitoring of the pH. Hydrolytic and chlorination reactions were demonstrated through monitoring of formation of HMF and chlorinated products under pyrolytic conditions using glucose or sucrose and amino acid mixtures. Copyright © 2014 Elsevier Ltd. All rights reserved.

Absolute rate constants of alkoxyl radical reactions in aqueous solution. [Tert-butyl hydroperoxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Erben-Russ, M.; Michel, C.; Bors, W.

1987-04-23

The pulse radiolysis technique was used to generate the alkoxyl radical derived from tert-butyl hydroperoxide (/sup t/BuOOH) in aqueous solution. The reactions of this radical with 2,2'-azinobis(3-ethyl-6-benzothiazolinesulfonate) (ABTS) and promethazine were monitored by kinetic spectroscopy. The unimolecular decay rate constant of the tert-butoxyl radical (/sup t/BuO) was determined to be 1.4 x 10/sup 6/ s/sup -1/. On the basis of this value, the rate constants for /sup t/BuO attack on quercetin, crocin, crocetin, ascorbate, isoascorbate, trolox c, glutathione, thymidine, adenosine, guanosine, and unsaturated fatty acids were determined. In addition, the reaction of /sup t/BuO with the polyunsaturated fatty acids (PUFA)more » was observed by directly monitoring the formation of the fatty acid pentadienyl radicals. Interestingly, the attack of /sup t/BuO on PUFA was found to be faster by about one order of magnitude as compared to the same reaction in a nonpolar solvent.« less

Near-infrared kinetic spectroscopy of the HO2 and C2H5O2 self-reactions and cross reactions.

PubMed

Noell, A C; Alconcel, L S; Robichaud, D J; Okumura, M; Sander, S P

2010-07-08

The self-reactions and cross reactions of the peroxy radicals C2H5O2 and HO2 were monitored using simultaneous independent spectroscopic probes to observe each radical species. Wavelength modulation (WM) near-infrared (NIR) spectroscopy was used to detect HO2, and UV absorption monitored C2H5O2. The temperature dependences of these reactions were investigated over a range of interest to tropospheric chemistry, 221-296 K. The Arrhenius expression determined for the cross reaction, k2(T) = (6.01(-1.47)(+1.95)) x 10(-13) exp((638 +/- 73)/T) cm3 molecules(-1) s(-1) is in agreement with other work from the literature. The measurements of the HO2 self-reaction agreed with previous work from this lab and were not further refined. The C2H5O2 self-reaction is complicated by secondary production of HO2. This experiment performed the first direct measurement of the self-reaction rate constant, as well as the branching fraction to the radical channel, in part by measurement of the secondary HO2. The Arrhenius expression for the self-reaction rate constant is k3(T) = (1.29(-0.27)(+0.34)) x 10(-13)exp((-23 +/- 61)/T) cm3 molecules(-1) s(-1), and the branching fraction value is alpha = 0.28 +/- 0.06, independent of temperature. These values are in disagreement with previous measurements based on end product studies of the branching fraction. The results suggest that better characterization of the products from RO2 self-reactions are required.

Optical in situ monitoring of plasma-enhanced atomic layer deposition process

NASA Astrophysics Data System (ADS)

Zeeshan Arshad, Muhammad; Jo, Kyung Jae; Kim, Hyun Gi; Jeen Hong, Sang

2018-06-01

An optical in situ process monitoring method for the early detection of anomalies in plasma process equipment is presented. Cyclic process steps of precursor treatment and plasma reaction for the deposition of an angstrom-scale film increase their complexity to ensure the process quality. However, a small deviation in process parameters, for instance, gas flow rate, process temperature, or RF power, may jeopardize the deposited film quality. As a test vehicle for the process monitoring, we have investigated the aluminum-oxide (Al2O3) encapsulation process in plasma-enhanced atomic layer deposition (PEALD) to form a moisture and oxygen diffusion barrier in organic-light emitting diodes (OLEDs). By optical in situ monitoring, we successfully identified the reduction in oxygen flow rates in the reaction steps, which resulted in a 2.67 times increase in the water vapor transmission ratio (WVTR) of the deposited Al2O3 films. Therefore, we are convinced that the suggested in situ monitoring method is useful for the detection of process shifts or drifts that adversely affect PEALD film quality.

Single-particle detection of products from atomic and molecular reactions in a cryogenic ion storage ring

NASA Astrophysics Data System (ADS)

Krantz, C.; Novotný, O.; Becker, A.; George, S.; Grieser, M.; Hahn, R. von; Meyer, C.; Schippers, S.; Spruck, K.; Vogel, S.; Wolf, A.

2017-04-01

We have used a single-particle detector system, based on secondary electron emission, for counting low-energetic (∼keV/u) massive products originating from atomic and molecular ion reactions in the electrostatic Cryogenic Storage Ring (CSR). The detector is movable within the cryogenic vacuum chamber of CSR, and was used to measure production rates of a variety of charged and neutral daughter particles. In operation at a temperature of ∼ 6 K , the detector is characterised by a high dynamic range, combining a low dark event rate with good high-rate particle counting capability. On-line measurement of the pulse height distributions proved to be an important monitor of the detector response at low temperature. Statistical pulse-height analysis allows to infer the particle detection efficiency of the detector, which has been found to be close to unity also in cryogenic operation at 6 K.

A plasmonic colorimetric strategy for visual miRNA detection based on hybridization chain reaction

NASA Astrophysics Data System (ADS)

Miao, Jie; Wang, Jingsheng; Guo, Jinyang; Gao, Huiguang; Han, Kun; Jiang, Chengmin; Miao, Peng

2016-08-01

In this work, a novel colorimetric strategy for miRNA analysis is proposed based on hybridization chain reaction (HCR)-mediated localized surface plasmon resonance (LSPR) variation of silver nanoparticles (AgNPs). miRNA in the sample to be tested is able to release HCR initiator from a solid interface to AgNPs colloid system by toehold exchange-mediated strand displacement, which then triggers the consumption of fuel strands with single-stranded tails for HCR. The final produced long nicked double-stranded DNA loses the ability to protect AgNPs from salt-induced aggregation. The stability variation of the colloid system can then be monitored by recording corresponding UV-vis spectrum and initial miRNA level is thus determined. This sensing system involves only four DNA strands which is quite simple. The practical utility is confirmed to be excellent by employing different biological samples.

A sensible technique to detect mollicutes impurities in human cells cultured in GMP condition.

PubMed

Ugolotti, Elisabetta; Vanni, Irene

2014-01-01

In therapeutic trials the use of manipulated cell cultures for clinical applications is often required. Mollicutes microorganism contamination of tissue cultures is a major problem because it can determine various and severe alterations in cellular function. Thus methods able to detect and trace cell cultures with Mollicutes contamination are needed in the monitoring of cells grown under good manufacturing practice conditions, and cell lines in continuous culture must be tested at regular intervals. We here describe a multiplex quantitative polymerase chain reaction assay able to detect contaminant Mollicutes species in a single-tube reaction through analysis of 16S-23S rRNA intergenic spacer regions and Tuf and P1 cytoadhesin genes. The method shows a sensitivity, specificity, and robustness comparable with the culture and the indicator cell culture as required by the European Pharmacopoeia guidelines and was validated following International Conference on Harmonization guidelines and Food and Drug Administration requirements.

Development of CMC hydrogels loaded with silver nano-particles for medical applications.

PubMed

Hebeish, Ali; Hashem, M; El-Hady, M M Abd; Sharaf, S

2013-01-30

Innovative CMC-based hydrogels with great potentials for usage in medical area were principally synthesized as per two strategies .The first involved reaction of epichlorohydrin in alkaline medium containing silver nitrate to yield silver nano-particles (AgNPs)-loaded CMC hydrogel. While CMC acted as stabilizing for AgNPs, trisodium citrate was added to the reaction medium to assist CMC in establishing reduction of Ag(+) to AgNPs. The second strategy entailed preparation of CMC hydrogel which assists the in situ preparation of AgNPs under the same conditions. In both strategies, factors affecting the characterization of AgNPs-loaded CMC hydrogels were studied. Analysis and characterization of the so obtained hydrogels were performed through monitoring swelling behavior, FTIR spectroscopy, SEM, EDX, UV-vis spectrophotometer and TEM. Antimicrobial activity of the hydrogels was examined and mechanisms involved in their synthesis were reported. Copyright © 2012 Elsevier Ltd. All rights reserved.

Mass Spectrometric Immunoassay and Multiple Reaction Monitoring as Targeted MS-based Quantitative Approaches in Biomarker Development: Potential Applications to Cardiovascular Disease and Diabetes

PubMed Central

Yassine, Hussein; Borges, Chad R.; Schaab, Matthew R.; Billheimer, Dean; Stump, Craig; Reaven, Peter; Lau, Serrine S.; Nelson, Randall

2014-01-01

Type 2 diabetes (T2DM) is an important risk factor for cardiovascular disease (CVD)—the leading cause of death in the US. Yet not all subjects with T2DM are at equal risk for CVD complications; the challenge lies in identifying those at greatest risk. Therapies directed towards treating conventional risk factors have failed to significantly reduce this residual risk in T2DM patients. Thus newer targets and markers are needed for the development and testing of novel therapies. Herein we review two complementary mass spectrometry-based approaches—Mass Spectrometric Immunoassay (MSIA) and tandem mass spectrometry as multiple reaction monitoring (MRM)—for the analysis of plasma proteins and post translational modifications (PTMs) of relevance to T2DM and CVD. Together, these complementary approaches allow for high-throughput monitoring of many PTMs and the absolute quantification of proteins near the low picomolar range. In this review article, we discuss the clinical relevance of the HDL proteome and Apolipoprotein A-I PTMs to T2DM and CVD as well as provide illustrative MSIA and MRM data on high density lipoprotein (HDL) proteins from T2DM patients to provide examples of how these mass spectrometry approaches can be applied to gain new insight regarding cardiovascular risk factors. Also discussed are the reproducibility, interpretation and limitations of each technique with an emphasis on their capacities to facilitate the translation of new biomarkers into clinical practice. PMID:23696124

A Sensitive Dilute-and-Shoot Approach for the Simultaneous Screening of 71 Stimulants and 7 Metabolites in Human Urine by LC-MS-MS with Dynamic MRM.

PubMed

Dong, Ying; Yan, Kuan; Ma, Yanhua; Wang, Shan; He, Genye; Deng, Jing; Yang, Zhiyong

2015-10-01

A novel, reliable and sensitive liquid chromatography-tandem mass spectrometry (LC-MS-MS) method was developed with dynamic multiple reaction monitoring (dMRM) mode for the simultaneous screening of 71 stimulants and 7 metabolites in human urine using unsophisticated MS instruments (Agilent triple-quadruple 6410 B mass spectrometer). With a known retention time of an analyte, dMRM algorithm monitors each MRM transition only around its expected retention time. Therefore, dMRM enables the maximization of dwell times and provides much higher sensitivity and reproducibility than the conventional multiple reaction monitoring mode (cMRM). After precipitation of protein, the urine sample was injected into LC-MS-MS system directly without sample pre-concentration. For comparison, cMRM and dMRM acquisitions were performed under the same chromatographic conditions. The result showed that the signal response and quality of the chromatograms for each stimulant improved significantly with dMRM over cMRM. The method has been fully validated giving limits of detection (0.1-25 ng/mL) satisfactory for its application to anti-doping analysis. The repeatability of the concentrations and the retention times are good both for intra- and for inter-day experiments (%CV of concentrations always <20 and %CV of retention times <0.5). The method also afforded satisfactory results in terms of accuracy, matrix effect and specificity. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Online monitoring of coffee roasting by proton transfer reaction time-of-flight mass spectrometry (PTR-ToF-MS): towards a real-time process control for a consistent roast profile.

PubMed

Wieland, Flurin; Gloess, Alexia N; Keller, Marco; Wetzel, Andreas; Schenker, Stefan; Yeretzian, Chahan

2012-03-01

A real-time automated process control tool for coffee roasting is presented to consistently and accurately achieve a targeted roast degree. It is based on the online monitoring of volatile organic compounds (VOC) in the off-gas of a drum roaster by proton transfer reaction time-of-flight mass spectrometry at a high time (1 Hz) and mass resolution (5,500 m/Δm at full width at half-maximum) and high sensitivity (better than parts per billion by volume). Forty-two roasting experiments were performed with the drum roaster being operated either on a low, medium or high hot-air inlet temperature (= energy input) and the coffee (Arabica from Antigua, Guatemala) being roasted to low, medium or dark roast degrees. A principal component analysis (PCA) discriminated, for each one of the three hot-air inlet temperatures, the roast degree with a resolution of better than ±1 Colorette. The 3D space of the three first principal components was defined based on 23 mass spectral profiles of VOCs and their roast degree at the end point of roasting. This provided a very detailed picture of the evolution of the roasting process and allowed establishment of a predictive model that projects the online-monitored VOC profile of the roaster off-gas in real time onto the PCA space defined by the calibration process and, ultimately, to control the coffee roasting process so as to achieve a target roast degree and a consistent roasting.

Analysis of Protein Adduction Kinetics by Quantitative Mass Spectrometry. Competing Adduction Reactions of Glutathione-S-Transferase P1-1 with Electrophiles

PubMed Central

Orton, Christopher R.; Liebler, Daniel C.

2007-01-01

Defining the mechanisms and consequences of protein adduction is crucial to understanding the toxicity of reactive electrophiles. Application of tandem mass spectrometry and data analysis algorithms enables detection and mapping of chemical adducts at the level of amino acid sequence. Nevertheless, detection of adducts does not indicate relative reactivity of different sites. Here we describe a method to measure the kinetics of competing adduction reactions at different sites on the same protein. Adducts are formed by electrophiles at Cys14 and Cys47 on the metabolic enzyme glutathione-S-transferase P1-1 and modification is accompanied by a loss of enzymatic activity. Relative quantitation of protein adducts was done by tagging N-termini of peptide digests with isotopically labeled phenyl isocyanate and tracking the ratio of light-tagged peptide adducts to heavy-tagged reference samples in liquid chromatography-tandem mass spectrometry analyses using a multiple reaction monitoring method. This approach was used to measure rate constants for adduction at both positions with two different model electrophiles, N-iodoacetyl-N-biotinylhexylenediamine and 1-biotinamido-4-(4′-[maleimidoethyl-cyclohexane]-carboxamido)butane. The results indicate that Cys47 was approximately 2–3-fold more reactive toward both electrophiles than was Cys14. This result was consistent with the relative reactivity of these electrophiles in a complex proteome system and with previously reported trends in reactivity of these sites. Kinetic analyses of protein modification reactions provide a means of evaluating the selectivity of reactive mediators of chemical toxicity. PMID:17433278

Application of fluid-rock reaction studies to in situ recovery from oil sand deposits, Alberta, Canada - I. Aqueous phase results for an experimental-statistical study of water-bitumen-shale reactions

NASA Astrophysics Data System (ADS)

Boon, J. A.; Hitchon, Brian

1983-02-01

In situ recovery operations in oil sand deposits effectively represent man-imposed low to intermediate temperature metamorphism of the sediments in the deposit. In order to evaluate some of the reactions which occur, a factorial experiment was earned out in which a shale from the Lower Cretaceous McMurray Formation in the Athabasca oil sand deposit of Alberta, in the presence or absence of bitumen, was subjected to hydrothermal treatment with aqueous fluids of varying pH and salinity, at two different temperatures, for periods up to 92 hours. The aqueous fluid was analyzed and the analytical data subjected to statistical factor analysis and analysis of variance, which enabled identification of the main processes, namely, cation exchange, the production of two types of colloidal material, and the dissolution of quartz There is also saturation of the aqueous phase by. as yet unidentified, "total organic carbon" and complete conversion and removal of all nitrogen in the shale to the aqueous phase. These reactions have implications with regards to the economics of the in situ recovery process, specifically with respect to the reuse and/or disposal of the produced water and the plugging of the pore space and hence of reduction of permeability between the injection and production wells. As a result of these experiments it is suggested that monitoring of the composition of the produced water from in situ recovery operations in oil sand deposits would be advisable.

A sensitive detection method for MPLW515L or MPLW515K mutation in chronic myeloproliferative disorders with locked nucleic acid-modified probes and real-time polymerase chain reaction.

PubMed

Pancrazzi, Alessandro; Guglielmelli, Paola; Ponziani, Vanessa; Bergamaschi, Gaetano; Bosi, Alberto; Barosi, Giovanni; Vannucchi, Alessandro M

2008-09-01

Acquired mutations in the juxtamembrane region of MPL (W515K or W515L), the receptor for thrombopoietin, have been described in patients with primary myelofibrosis or essential thrombocythemia, which are chronic myeloproliferative disorders. We have developed a real-time polymerase chain reaction assay for the detection and quantification of MPL mutations that is based on locked nucleic acid fluorescent probes. Mutational analysis was performed using DNA from granulocytes. Reference curves were obtained using cloned fragments of MPL containing either the wild-type or mutated sequence; the predicted sensitivity level was at least 0.1% mutant allele in a wild-type background. None of the 60 control subjects presented with a MPLW515L/K mutation. Of 217 patients with myelofibrosis, 19 (8.7%) harbored the MPLW515 mutation, 10 (52.6%) with the W515L allele. In one case, both the W515L and W515K alleles were detected by real-time polymerase chain reaction. By comparing results obtained with conventional sequencing, no erroneous genotype attribution using real-time polymerase chain reaction was found, whereas one patient considered wild type according to sequence analysis actually harbored a low W515L allele burden. This is a simple, sensitive, and cost-effective procedure for large-scale screening of the MPLW515L/K mutation in patients suspected to have a myeloproliferative disorder. It can also provide a quantitative estimate of mutant allele burden that might be useful for both patient prognosis and monitoring response to therapy.

Single-molecule nanopore enzymology

PubMed Central

Wloka, Carsten; Maglia, Giovanni

2017-01-01

Biological nanopores are a class of membrane proteins that open nanoscale water-conduits in biological membranes. When they are reconstituted in artificial membranes and a bias voltage is applied across the membrane, the ionic current passing through individual nanopores can be used to monitor chemical reactions, to recognize individual molecules and, of most interest, to sequence DNA. More recently, proteins and enzymes have started being analysed with nanopores. Monitoring enzymatic reactions with nanopores, i.e. nanopore enzymology, has the unique advantage that it allows long-timescale observations of native proteins at the single-molecule level. Here we describe the approaches and challenges in nanopore enzymology. PMID:28630164

The Heterogeneous Oxidation of Organic Droplets -Temperature and Physical Phase Effects

NASA Astrophysics Data System (ADS)

Hung, H.; Tang, C.; Lin, L.

2008-12-01

The heterogeneous reactions of oleic acid droplets with ozone are studied at different temperatures to imitating the atmospheric condition. The reactions are monitored concomitantly by using attenuated total reflectance Fourier Transform infrared spectroscopy (ATR-FT-IR) for the organic species and UV-VIS spectrometry for the ozone concentration, in order to investigate reaction rate discrepancies reported in literature as well as the oxidation mechanism, temperature and physical phase effects. The less and semi- volatile products are identified and resolved by a liquid chromatography and a gas chromatography mass spectrometer, respectively. The identified products are predominantly composed by nananoic acid and azelaic acid and might be due to propagation reactions possibly initiated by a secondary reaction such as the stabilized Criegee intermediates reacting with oleic acid. For temperature effect, the oxidation rate decreases with temperature when the oleic acid droplets are in the same physical phases. As oleic acid turns into the solid phase, the oxidation mechanism is observed to be different from the liquid phase. Furthermore, the concentration of ozone was monitored to examine the kinetics of the oxidation reaction. The integrated ozone profile recorded by UV-VIS spectrometry shows that the consumed ozone represents only approximately 12% of total oleic acid for the solid cases at 4°C in contrast to 30% for the liquid cases at 25°C, and hence confirmed the existence of secondary reactions.

Method and apparatus for controlling gas evolution from chemical reactions

DOEpatents

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.

High Performance Computer Cluster for Theoretical Studies of Roaming in Chemical Reactions

DTIC Science & Technology

2016-08-30

High-performance Computer Cluster for Theoretical Studies of Roaming in Chemical Reactions A dedicated high-performance computer cluster was...SPONSORING/MONITORING AGENCY NAME(S) AND ADDRESS (ES) U.S. Army Research Office P.O. Box 12211 Research Triangle Park, NC 27709-2211 Computer cluster ...peer-reviewed journals: Final Report: High-performance Computer Cluster for Theoretical Studies of Roaming in Chemical Reactions Report Title A dedicated

A Self-Powered Wearable Noninvasive Electronic-Skin for Perspiration Analysis Based on Piezo-Biosensing Unit Matrix of Enzyme/ZnO Nanoarrays.

PubMed

Han, Wuxiao; He, Haoxuan; Zhang, Linlin; Dong, Chuanyi; Zeng, Hui; Dai, Yitong; Xing, Lili; Zhang, Yan; Xue, Xinyu

2017-09-06

The emerging multifunctional flexible electronic-skin for establishing body-electric interaction can enable real-time monitoring of personal health status as a new personalized medicine technique. A key difficulty in the device design is the flexible power supply. Here a self-powered wearable noninvasive electronic-skin for perspiration analysis has been realized on the basis of a piezo-biosensing unit matrix of enzyme/ZnO nanoarrays. The electronic-skin can detect lactate, glucose, uric acid, and urea in the perspiration, and no outside electrical power supply or battery is used in the biosensing process. The piezoelectric impulse of the piezo-biosensing units serves as the power supply and the data biosensor. The working mechanism can be ascribed to the piezoelectric-enzymatic-reaction coupling effect of enzyme/ZnO nanowires. The electronic-skin can real-time/continuously monitor the physiological state of a runner through analyzing the perspiration on his skin. This approach can promote the development of a new-type of body electric and self-powered biosensing electronic-skin.

In vitro lysis and acute transfusion reactions with hemolysis caused by inappropriate storage of canine red blood cell products.

PubMed

Patterson, J; Rousseau, A; Kessler, R J; Giger, U

2011-01-01

Transfusion of red blood cell (RBC) products carries considerable risk for adverse reactions, including life-threatening hemolytic reactions. To report the occurrence and investigation of life-threatening acute transfusion reactions with hemolysis in dogs likely related to inappropriate blood product storage. Four dogs with acute transfusion reactions and other recipients of blood products. Medical records were reviewed from 4 dogs with suspected acute hemolytic transfusion reactions after receiving RBC products at a veterinary clinic over a 1-month period. Medical records of other animals receiving blood products in the same time period also were reviewed. Blood compatibility and product quality were assessed, subsequent transfusions were closely monitored, and products were diligently audited. During or immediately after RBC product transfusion, 4 dogs developed hemolysis, hemoglobinuria, or both. Two dogs died and 1 was euthanized because of progressive clinical signs compatible with an acute hemolytic transfusion reaction. Blood type and blood compatibility were confirmed. RBC units from 2 blood banks were found to be hemolyzed after storage in the clinic's refrigerator; no bacterial contamination was identified. After obtaining a new refrigerator dedicated to blood product storage, the problem of hemolyzed units and acute transfusion reactions with hemolysis completely resolved. Acute life-threatening transfusion reactions can be caused by inappropriate storage of RBC products. In addition to infectious disease screening and ensuring blood-type compatibility, quality assessment of blood products, appropriate collection, processing, and storage techniques as well as recipient monitoring are critical to provide safe, effective transfusions. Copyright © 2011 by the American College of Veterinary Internal Medicine.

PULSED ELECTROCHEMICAL TECHNIQUE FOR MONITORING ANTIBODY-ANTIGEN REACTIONS AT INTERFACES. (R825323)

EPA Science Inventory

Abstract

The mechanism of pulsed potential waveform for monitoring antibody_¯antigen interactions at immunosensor interfaces is discussed. Some examples of antibody_¯antigen interactions at quartz crystal microbalance and polymer-modified ...

Progress toward the development of an implantable sensor for glucose.

PubMed

Wilson, G S; Zhang, Y; Reach, G; Moatti-Sirat, D; Poitout, V; Thévenot, D R; Lemonnier, F; Klein, J C

1992-09-01

The development of an electrochemically based implantable sensor for glucose is described. The sensor is needle-shaped, about the size of a 28-gauge needle. It is flexible and must be implanted subcutaneously by using a 21-gauge catheter, which is then removed. When combined with a monitoring unit, this device, based on the glucose oxidase-catalyzed oxidation of glucose, reliably monitors glucose concentrations for as long as 10 days in rats. Various design considerations, including the decision to monitor the hydrogen peroxide produced in the enzymatic reaction, are discussed. Glucose constitutes the most important future target analyte for continuous monitoring, but the basic methodology developed for glucose could be applied to several other analytes such as lactate or ascorbate. The success in implementation of such a device depends on a reaction of the tissue surrounding the implant so as not to interfere with the proper functioning of the sensor. Histochemical evidence indicates that the tissue response leads to enhanced sensor performance.

Comprehensive Analyzer for Biogenic Volatile Organic Compounds Detected as Total Ozone Reactivity

NASA Astrophysics Data System (ADS)

Matsumoto, J.

2011-12-01

Volatile organic compounds, VOCs, are emitted from various sources into the atmosphere. Through the reactions of VOCs with atmospheric radicals (eg. daytime OH, nighttime NO3, and all-day O3), formation of photochemical oxidants and secondary organic aerosols, SOA, are important. To investigate the mechanisms of reactions in the atmosphere and to control such secondary products effectively, it is essential to capture the behavior of VOC emission with the radical reactivity of VOCs considered. Recently, in addition to OH reactions of anthropogenic VOCs, SOA formation due to ozonolysis of biogenic VOCs (BVOCs) is one of the hottest topics in the atmospheric chemistry. It is difficult to analyze all the species individually due to the great number of VOCs. In this study, a comprehensive tool for capturing the total reactivity of BVOCs with ozone is realized utilizing a chemiluminescence ozone analyzer. A sensitive and fast-response ozone analyzer was developed based on an existing chemiluminescent NO analyzer (CLD). The CLD-O3 analyzer was used to monitor the fast variation of O3 in the sample of the VOC + O3 experiment. When O3 was added to the VOC sample, the reduction of O3 due to VOC was monitored and the O3 reactivity RO3 was determined with the reaction time considered. Dependence of the response of analyzer on the reaction time and the reactivity of sample was examined and confirmed as reasonable. As a result, VOCs can be detected at the level of ppbv (as limonene, S/N = 3). The detection limit of RO3 was 0.0002 s-1. For the test of ozone reactivity measurement of BVOCs emitted from the real vegetation, variation of ozone reactivity was significantly observed after the nursery was put into a closed chamber. In addition, just after the leaves of the plant were physically stimulated, observed reactivity increased. It was experimentally confirmed that stimulus to the leaves of the plant resulted in the increase of total BVOC emission. Consequently, it was confirmed that the analyzer be useful to investigate the real-time analysis of BVOC emission from the vegetation at the level of ppbv.

Real-time activity monitoring of New Delhi metallo-β-lactamase-1 in living bacterial cells by UV-Vis spectroscopy.

PubMed

Yang, Ke-Wu; Zhou, Yajun; Ge, Ying; Zhang, Yuejuan

2017-07-13

We report an UV-Vis method for monitoring the hydrolysis of the β-lactam antibiotics inside living bacterial cells. Cell-based studies demonstrated that the hydrolysis of cefazolin was inhibited by three known NDM-1 inhibitors. This approach can be applied to the monitoring of reactions in a complex biological system, for instance in medical testing.

Nonthermal microwave effects revisited: on the importance of internal temperature monitoring and agitation in microwave chemistry.

PubMed

Herrero, M Antonia; Kremsner, Jennifer M; Kappe, C Oliver

2008-01-04

The concept of nonthermal microwave effects has received considerable attention in recent years and is the subject of intense debate in the scientific community. Nonthermal microwave effects have been postulated to result from a direct stabilizing interaction of the electric field with specific (polar) molecules in the reaction medium that is not related to a macroscopic temperature effect. In order to probe the existence of nonthermal microwave effects, four synthetic transformations (Diels-Alder cycloaddition, alkylation of triphenylphosphine and 1,2,4-triazole, direct amide bond formation) were reevaluated under both microwave dielectric heating and conventional thermal heating. In all four cases, previous studies have claimed the existence of nonthermal microwave effects in these reactions. Experimentally, significant differences in conversion and/or product distribution comparing the conventionally and microwave-heated experiments performed at the same measured reaction temperature were found. The current reevaluation of these reactions was performed in a dedicated reactor setup that allowed accurate internal reaction temperature measurements using a multiple fiber-optic probe system. Using this technology, the importance of efficient stirring and internal temperature measurement in microwave-heated reactions was made evident. Inefficient agitation leads to temperature gradients within the reaction mixture due to field inhomogeneities in the microwave cavity. Using external infrared temperature sensors in some cases results in significant inaccuracies in the temperature measurement. Applying the fiber-optic probe temperature monitoring device, a critical reevaluation of all four reactions has provided no evidence for the existence of nonthermal microwave effects. Ensuring efficient agitation of the reaction mixture via magnetic stirring, no significant differences in terms of conversion and selectivity between experiments performed under microwave or oil bath conditions at the same internally measured reaction temperatures were experienced. The observed effects were purely thermal and not related to the microwave field.

Widely-targeted quantitative lipidomics methodology by supercritical fluid chromatography coupled with fast-scanning triple quadrupole mass spectrometry.

PubMed

Takeda, Hiroaki; Izumi, Yoshihiro; Takahashi, Masatomo; Paxton, Thanai; Tamura, Shohei; Koike, Tomonari; Yu, Ying; Kato, Noriko; Nagase, Katsutoshi; Shiomi, Masashi; Bamba, Takeshi

2018-05-03

Lipidomics, the mass spectrometry-based comprehensive analysis of lipids, has attracted attention as an analytical approach to provide novel insight into lipid metabolism and to search for biomarkers. However, an ideal method for both comprehensive and quantitative analysis of lipids has not been fully developed. Herein, we have proposed a practical methodology for widely-targeted quantitative lipidome analysis using supercritical fluid chromatography fast-scanning triple-quadrupole mass spectrometry (SFC/QqQMS) and theoretically calculated a comprehensive lipid multiple reaction monitoring (MRM) library. Lipid classes can be separated by SFC with a normal phase diethylamine-bonded silica column with high-resolution, high-throughput, and good repeatability. Structural isomers of phospholipids can be monitored by mass spectrometric separation with fatty acyl-based MRM transitions. SFC/QqQMS analysis with an internal standard-dilution method offers quantitative information for both lipid class and individual lipid molecular species in the same lipid class. Additionally, data acquired using this method has advantages including reduction of misidentification and acceleration of data analysis. Using the SFC/QqQMS system, alteration of plasma lipid levels in myocardial infarction-prone rabbits to the supplementation of eicosapentaenoic acid was first observed. Our developed SFC/QqQMS method represents a potentially useful tool for in-depth studies focused on complex lipid metabolism and biomarker discovery. Published under license by The American Society for Biochemistry and Molecular Biology, Inc.

Mass spectrometric directed system for the continuous-flow synthesis and purification of diphenhydramine.

PubMed

Loren, Bradley P; Wleklinski, Michael; Koswara, Andy; Yammine, Kathryn; Hu, Yanyang; Nagy, Zoltan K; Thompson, David H; Cooks, R Graham

2017-06-01

A highly integrated approach to the development of a process for the continuous synthesis and purification of diphenhydramine is reported. Mass spectrometry (MS) is utilized throughout the system for on-line reaction monitoring, off-line yield quantitation, and as a reaction screening module that exploits reaction acceleration in charged microdroplets for high throughput route screening. This effort has enabled the discovery and optimization of multiple routes to diphenhydramine in glass microreactors using MS as a process analytical tool (PAT). The ability to rapidly screen conditions in charged microdroplets was used to guide optimization of the process in a microfluidic reactor. A quantitative MS method was developed and used to measure the reaction kinetics. Integration of the continuous-flow reactor/on-line MS methodology with a miniaturized crystallization platform for continuous reaction monitoring and controlled crystallization of diphenhydramine was also achieved. Our findings suggest a robust approach for the continuous manufacture of pharmaceutical drug products, exemplified in the particular case of diphenhydramine, and optimized for efficiency and crystal size, and guided by real-time analytics to produce the agent in a form that is readily adapted to continuous synthesis.

Gas-phase kinetics during diamond growth: CH4 as-growth species

NASA Astrophysics Data System (ADS)

Harris, Stephen J.

1989-04-01

We have used a one-dimensional kinetic analysis to model the gas-phase chemistry that occurred during the diamond growth experiments of Chauhan, Angus, and Gardner [J. Appl. Phys. 47, 4746 (1976)]. In those experiments the weight of diamond seed crystals heated by lamps in a CH4/H2 environment was monitored by a microbalance. No filament or electric discharge was present. Our analysis shows that diamond growth occurred in this system by direct reaction of CH4 on the diamond surface. C2H2 and CH3, which have been proposed as diamond growth species, played no significant role there, although our results do not address their possible contributions in other systems such as filament- or plasma-assisted diamond growth.

The Catalyzed Substitution of CO by Isonitriles on (M(CO)6) (M=Cr, Mo, W).

ERIC Educational Resources Information Center

Albers, Michel O.; Singleton, Eric

1986-01-01

Describes experiments designed to: (1) familiarize students with inert atmosphere techniques; (2) teach monitoring reactions with thin-layer chromatography and infrared spectroscopy, isolation, and purification by crystallization and column chromatography; (3) estimate product purity spectroscopically; and (4) characterize reaction products by…

Gold patterned biochips for on-chip immuno-MALDI-TOF MS: SPR imaging coupled multi-protein MS analysis.

PubMed

Kim, Young Eun; Yi, So Yeon; Lee, Chang-Soo; Jung, Yongwon; Chung, Bong Hyun

2012-01-21

Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF-MS) analysis of immuno-captured target protein efficiently complements conventional immunoassays by offering rich molecular information such as protein isoforms or modifications. Direct immobilization of antibodies on MALDI solid support enables both target enrichment and MS analysis on the same plate, allowing simplified and potentially multiplexing protein MS analysis. Reliable on-chip immuno-MALDI-TOF MS for multiple biomarkers requires successful adaptation of antibody array biochips, which also must accommodate consistent reaction conditions on antibody arrays during immuno-capture and MS analysis. Here we developed a facile fabrication process of versatile antibody array biochips for reliable on-chip MALDI-TOF-MS analysis of multiple immuno-captured proteins. Hydrophilic gold arrays surrounded by super-hydrophobic surfaces were formed on a gold patterned biochip via spontaneous chemical or protein layer deposition. From antibody immobilization to MALDI matrix treatment, this hydrophilic/phobic pattern allowed highly consistent surface reactions on each gold spot. Various antibodies were immobilized on these gold spots both by covalent coupling or protein G binding. Four different protein markers were successfully analyzed on the present immuno-MALDI biochip from complex protein mixtures including serum samples. Tryptic digests of captured PSA protein were also effectively detected by on-chip MALDI-TOF-MS. Moreover, the present MALDI biochip can be directly applied to the SPR imaging system, by which antibody and subsequent antigen immobilization were successfully monitored.

A survey of analytical methods employed for monitoring of Advanced Oxidation/Reduction Processes for decomposition of selected perfluorinated environmental pollutants.

PubMed

Trojanowicz, Marek; Bobrowski, Krzysztof; Szostek, Bogdan; Bojanowska-Czajka, Anna; Szreder, Tomasz; Bartoszewicz, Iwona; Kulisa, Krzysztof

2018-01-15

The monitoring of Advanced Oxidation/Reduction Processes (AO/RPs) for the evaluation of the yield and mechanisms of decomposition of perfluorinated compounds (PFCs) is often a more difficult task than their determination in the environmental, biological or food samples with complex matrices. This is mostly due to the formation of hundreds, or even thousands, of both intermediate and final products. The considered AO/RPs, involving free radical reactions, include photolytic and photocatalytic processes, Fenton reactions, sonolysis, ozonation, application of ionizing radiation and several wet oxidation processes. The main attention is paid to the most commonly occurring PFCs in the environment, namely PFOA and PFOS. The most powerful and widely exploited method for this purpose is without a doubt LC/MS/MS, which allows the identification and trace quantitation of all species with detectability and resolution power depending on the particular instrumental configurations. The GC/MS is often employed for the monitoring of volatile fluorocarbons, confirming the formation of radicals in the processes of C‒C and C‒S bonds cleavage. For the direct monitoring of radicals participating in the reactions of PFCs decomposition, the molecular spectrophotometry is employed, especially electron paramagnetic resonance (EPR). The UV/Vis spectrophotometry as a detection method is of special importance in the evaluation of kinetics of radical reactions with the use of pulse radiolysis methods. The most commonly employed for the determination of the yield of mineralization of PFCs is ion-chromatography, but there is also potentiometry with ion-selective electrode and the measurements of general parameters such as Total Organic Carbon and Total Organic Fluoride. The presented review is based on about 100 original papers published in both analytical and environmental journals. Copyright © 2017 Elsevier B.V. All rights reserved.

Measurement of excitation function of {sup nat}B(p,x){sup 7}Be nuclear reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ditroi, F.; Fenyvesi, A.; Takacs, S.

1994-12-31

Boron of natural composition was irradiated to measure the cross section function of the {sup nat}B(p,x){sup 7}Be nuclear reaction. The reaction is very important from the point of view of Thin Layer Activation (TLA) technique to monitor the wear of boron containing superhard materials (e.g. BN). The aim was to determine the cross section of above reaction in the energy region used in wear measurements because practically there is no cross section data available below 10 MeV.

Sensing Free Sulfur Dioxide in Wine

PubMed Central

Monro, Tanya M.; Moore, Rachel L.; Nguyen, Mai-Chi; Ebendorff-Heidepriem, Heike; Skouroumounis, George K.; Elsey, Gordon M.; Taylor, Dennis K.

2012-01-01

Sulfur dioxide (SO2) is important in the winemaking process as it aids in preventing microbial growth and the oxidation of wine. These processes and others consume the SO2 over time, resulting in wines with little SO2 protection. Furthermore, SO2 and sulfiting agents are known to be allergens to many individuals and for that reason their levels need to be monitored and regulated in final wine products. Many of the current techniques for monitoring SO2 in wine require the SO2 to be separated from the wine prior to analysis. This investigation demonstrates a technique capable of measuring free sulfite concentrations in low volume liquid samples in white wine. This approach adapts a known colorimetric reaction to a suspended core optical fiber sensing platform, and exploits the interaction between guided light located within the fiber voids and a mixture of the wine sample and a colorimetric analyte. We have shown that this technique enables measurements to be made without dilution of the wine samples, thus paving the way towards real time in situ wine monitoring. PMID:23112627

Cost-Effectiveness Analysis of Plasma Versus Recombinant Factor VIIa for Placing Intracranial Pressure Monitors in Pretransplant Patients With Acute Liver Failure.

PubMed

Pham, Huy P; Sireci, Anthony N; Kim, Chong H; Schwartz, Joseph

2014-09-01

Both plasma- and recombinant activated factor VII (rFVIIa)-based algorithms can be used to correct coagulopathy in preliver transplant patients with acute liver failure requiring intracranial pressure monitor (ICPM) placement. A decision model was created to compare the cost-effectiveness of these methods. A 70-kg patient could receive either 1 round of plasma followed by coagulation testing or 2 units of plasma and 40 μg/kg rFVIIa. Intracranial pressure monitor is placed without coagulation testing after rFVIIa administration. In the plasma algorithm, the probability of ICPM placement was estimated based on expected international normalized ratio (INR) after plasma administration. Risks of rFVIIa thrombosis and transfusion reactions were also included. The model was run for patients with INRs ranging from 2 to 6 with concomitant adjustments to model parameters. The model supported the initial use of rFVIIa for ICPM placement as a cost-effective treatment when INR ≥2 (with incremental cost-effectiveness ratio of at most US$7088.02). © The Author(s) 2014.

UPLC-MS/MS method for therapeutic drug monitoring of 10 antibiotics used in intensive care units.

PubMed

El-Najjar, Nahed; Hösl, Julian; Holzmann, Thomas; Jantsch, Jonathan; Gessner, André

2018-03-01

A large variation in the levels of different ß-lactams and other antibiotics used in critically ill patients has been documented. The aim of this study is to establish and validate a fast, ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the simultaneous analysis of ten antibiotics (Meropenem, Cefepime, Ceftazidime, Piperacillin, Benzylpenicillin, Ampicillin, Flucloxacillin, Linezolid, and Sulfamethoxazole/Trimethoprim) in human plasma according to European Medicines Agency (EMA) guidelines. Protein precipitation with ice-cold methanol containing 9 isotopically labeled internal standards was used for sample clean up. Antibiotics were detected, following a 4-minute gradient separation, in multiple reactions monitoring (MRM) using API 4000 instrument equipped with electrospray source operating in positive ion mode. The lower limit of quantification was 0.1 mg/L for Meropenem, Ceftazidime, Piperacillin, Ampicillin, Flucloxacillin, and Sulfamethoxazole; 0.05 mg/L for Cefepime, Benzylpenicillin, and Trimethoprim; and 0.02 mg/L for Linezolid. The method proved to be precise and accurate and applicable for therapeutic drug monitoring and other pharmacokinetic studies. Copyright © 2017 John Wiley & Sons, Ltd.

A Monitoring System for the LHCb Data Flow

NASA Astrophysics Data System (ADS)

Barbosa, João; Gaspar, Clara; Jost, Beat; Frank, Markus; Cardoso, Luis G.

2017-06-01

The LHCb experiment uses the LHC accelerator for the collisions that produce the physics data necessary for analysis. The data produced by the detector by measuring the results of the collisions at a rate of 40 MHz are read out by a complex data acquisition (DAQ) system, which is summarily described in this paper. Distributed systems of such dimensions rely on monitoring and control systems that account for the numerous faults that can happen throughout the whole operation. With this in mind, a new system was created to extend the monitoring of the readout system, in this case by providing an overview of what is happening in each stage of the DAQ process, starting in the hardware trigger performed right after the detector measurements and ending in the local storage of the experiment. This system, a complement to the current run control (experimental control system), intends to shorten reaction times when a problem occurs by providing the operators with detailed information of where a certain fault is occurring. The architecture of the tool and its utilization by the experiment operators are described in this paper.

Chromatographic separation and continuously referenced, on-line monitoring of creatine kinase isoenzymes by use of an immobilized-enzyme microreactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Denton, M.S.; Bostick, W.D.; Dinsmore, S.R.

1978-08-01

We describe a new concept in continuously referenced monitoring of the isoenzyme activities of creatine kinase (EC 2.7.3.2) after liquid-chromatographic separation. After separation on a diethylaminoethyl-Sephacel column, the three isoenzymes of creatine kinase undergo a series of upled enzyme reactions, ultimately resulting in the formation of ultraviolet-detectable NADPH. A major advantage of this detection system is the immobilized-enzyme microreactor (2 x 17 mm), which may be removed and stored refrigerated when not in use. A split-stream configuration allows self-blanking of endogenous ultraviolet-absorbing constituents in authentic sera samples, which would otherwise make definitive diagnosis and quantitation difficult or impossible. This detectionmore » system is applicable to the automated analysis of creatine kinase isoenzymes in the clinical laboratory. 5 figures; 42 references.« less

Bed Bug Detection: Current Technologies and Future Directions

PubMed Central

Vaidyanathan, Rajeev; Feldlaufer, Mark F.

2013-01-01

Technologies to detect bed bugs have not kept pace with their global resurgence. Early detection is critical to prevent infestations from spreading. Detection based exclusively on bites is inadequate, because reactions to insect bites are non-specific and often misdiagnosed. Visual inspections are commonly used and depend on identifying live bugs, exuviae, or fecal droplets. Visual inspections are inexpensive, but they are time-consuming and unreliable when only a few bugs are present. Use of a dog to detect bed bugs is gaining in popularity, but it can be expensive, may unintentionally advertise a bed bug problem, and is not foolproof. Passive monitors mimic natural harborages; they are discreet and typically use an adhesive to trap bugs. Active monitors generate carbon dioxide, heat, a pheromone, or a combination to attract bed bugs to a trap. New technologies using DNA analysis, mass spectrometry, and electronic noses are innovative but impractical and expensive for widespread use. PMID:23553226

[Medical negligence in surgery: 112 cases retrospective analysis].

PubMed

Xiang, Jian; Chang, Lin; Wang, Xu; Zhang, Feng-Qin

2013-06-01

To explore the general characteristics of medical negligence in surgery in order to provide the reference for forensic practices. One hundred and twelve cases of medical negligence in surgical department were retrospectively analyzed in Fada Institute of Forensic Medicine and Science from 2008 to 2010. The common types of medical negligence cases in the surgery were improper operation procedure (28.57%), failure of consent (26.79%), and inadequate monitoring (22.32%). The results of complications included disability or functional impairment (61.61%), death (31.25%) and transient impairment with no obvious adverse reactions (7.14%). The most common roles played by the medical negligence cases were minor role (26.79%), equal role (19.64%), and slight role (14.29%). Significant attention should be paid to the operation procedure, consent, and monitoring. It should be cautious to not make assessment on involvement degree of medical negligence.

Microbial quantification in activated sludge: the hits and misses.

PubMed

Hall, S J; Keller, J; Blackall, L L

2003-01-01

Since the implementation of the activated sludge process for treating wastewater, there has been a reliance on chemical and physical parameters to monitor the system. However, in biological nutrient removal (BNR) processes, the microorganisms responsible for some of the transformations should be used to monitor the processes with the overall goal to achieve better treatment performance. The development of in situ identification and rapid quantification techniques for key microorganisms involved in BNR are required to achieve this goal. This study explored the quantification of Nitrospira, a key organism in the oxidation of nitrite to nitrate in BNR. Two molecular genetic microbial quantification techniques were evaluated: real-time polymerase chain reaction (PCR) and fluorescence in situ hybridisation (FISH) followed by digital image analysis. A correlation between the Nitrospira quantitative data and the nitrate production rate, determined in batch tests, was attempted. The disadvantages and advantages of both methods will be discussed.

RAPID MONITORING BY QPCR FOR PATHOGENIC ASPERGILLUS DURING CARPET REMOVAL FROM A HOSPITAL

EPA Science Inventory

Monitoring for pathogenic Aspergillus species using a rapid, highly sensitive, quantitative polymerase 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 conventi...

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

PubMed

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.

Method and apparatus for controlling gas evolution from chemical reactions

DOEpatents

Skorpik, J.R.; Dodson, M.G.

1999-05-25

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. 8 figs.

Direct, rapid, and label-free detection of enzyme-substrate interactions in physiological buffers using CMOS-compatible nanoribbon sensors.

PubMed

Mu, Luye; Droujinine, Ilia A; Rajan, Nitin K; Sawtelle, Sonya D; Reed, Mark A

2014-09-10

We demonstrate the versatility of Al2O3-passivated Si nanowire devices ("nanoribbons") in the analysis of enzyme-substrate interactions via the monitoring of pH change. Our approach is shown to be effective through the detection of urea in phosphate buffered saline (PBS), and penicillinase in PBS and urine, at limits of detection of <200 μM and 0.02 units/mL, respectively. The ability to extract accurate enzyme kinetics and the Michaelis-Menten constant (Km) from the acetylcholine-acetylcholinesterase reaction is also demonstrated.

Particle beam experiments for the analysis of reactive sputtering processes in metals and polymer surfaces

NASA Astrophysics Data System (ADS)

Corbella, Carles; Grosse-Kreul, Simon; Kreiter, Oliver; de los Arcos, Teresa; Benedikt, Jan; von Keudell, Achim

2013-10-01

A beam experiment is presented to study heterogeneous reactions relevant to plasma-surface interactions in reactive sputtering applications. Atom and ion sources are focused onto the sample to expose it to quantified beams of oxygen, nitrogen, hydrogen, noble gas ions, and metal vapor. The heterogeneous surface processes are monitored in situ by means of a quartz crystal microbalance and Fourier transform infrared spectroscopy. Two examples illustrate the capabilities of the particle beam setup: oxidation and nitriding of aluminum as a model of target poisoning during reactive magnetron sputtering, and plasma pre-treatment of polymers (PET, PP).

Revealing time bunching effect in single-molecule enzyme conformational dynamics.

PubMed

Lu, H Peter

2011-04-21

In this perspective, we focus our discussion on how the single-molecule spectroscopy and statistical analysis are able to reveal enzyme hidden properties, taking the study of T4 lysozyme as an example. Protein conformational fluctuations and dynamics play a crucial role in biomolecular functions, such as in enzymatic reactions. Single-molecule spectroscopy is a powerful approach to analyze protein conformational dynamics under physiological conditions, providing dynamic perspectives on a molecular-level understanding of protein structure-function mechanisms. Using single-molecule fluorescence spectroscopy, we have probed T4 lysozyme conformational motions under the hydrolysis reaction of a polysaccharide of E. coli B cell walls by monitoring the fluorescence resonant energy transfer (FRET) between a donor-acceptor probe pair tethered to T4 lysozyme domains involving open-close hinge-bending motions. Based on the single-molecule spectroscopic results, molecular dynamics simulation, a random walk model analysis, and a novel 2D statistical correlation analysis, we have revealed a time bunching effect in protein conformational motion dynamics that is critical to enzymatic functions. Bunching effect implies that conformational motion times tend to bunch in a finite and narrow time window. We show that convoluted multiple Poisson rate processes give rise to the bunching effect in the enzymatic reaction dynamics. Evidently, the bunching effect is likely common in protein conformational dynamics involving in conformation-gated protein functions. In this perspective, we will also discuss a new approach of 2D regional correlation analysis capable of analyzing fluctuation dynamics of complex multiple correlated and anti-correlated fluctuations under a non-correlated noise background. Using this new method, we are able to map out any defined segments along the fluctuation trajectories and determine whether they are correlated, anti-correlated, or non-correlated; after which, a cross correlation analysis can be applied for each specific segment to obtain a detailed fluctuation dynamics analysis.

Derivatization of beta-dicarbonyl compound with 2,4-dinitrophenylhydrazine to enhance mass spectrometric detection: application in quantitative analysis of houttuynin in human plasma.

PubMed

Duan, Xiaotao; Zhong, Dafang; Chen, Xiaoyan

2008-06-01

Houttuynin (decanoyl acetaldehyde), a beta-dicarbonyl compound, is the major antibacterial constituent in the volatile oil of Houttuynina cordata Thunb. In the present work, detection of houttuynin in human plasma based on the chemical derivatization with 2,4-dinitrophenylhydrazine (DNPH) coupled with liquid chromatography/tandem mass spectrometry was described. The primary reaction products between the beta-dicarbonyl compound and DNPH in aqueous phase were identified as heterocyclic structures, of which the mass spectrometric ionization and fragmentation behavior were characterized with the aid of high-resolution multistage mass spectral analysis. For quantification, houttuynin and internal standard (IS, benzophenone) in plasma were firstly converted to their DNPH derivatives without sample purification, then extracted from human plasma with n-hexane and detected by liquid chromatography tandem mass spectrometry performed in selected reaction monitoring (SRM) mode. This method allowed for a lower limit of quantification (LLOQ) of 1.0 ng/ml using 100-microl plasma. The validation results showed high accuracy (%bias < 2.1) and precision (%CV < 7.2) at broad linear dynamic range (1.0-5000 ng/ml). The simple and quantitative derivatization coupled with tandem mass spectrometric analysis facilitates a sensitive and robust method for the determination of plasma houttuynin in pharmacokinetic studies.

Hybrid Semantic Analysis for Mapping Adverse Drug Reaction Mentions in Tweets to Medical Terminology.

PubMed

Emadzadeh, Ehsan; Sarker, Abeed; Nikfarjam, Azadeh; Gonzalez, Graciela

2017-01-01

Social networks, such as Twitter, have become important sources for active monitoring of user-reported adverse drug reactions (ADRs). Automatic extraction of ADR information can be crucial for healthcare providers, drug manufacturers, and consumers. However, because of the non-standard nature of social media language, automatically extracted ADR mentions need to be mapped to standard forms before they can be used by operational pharmacovigilance systems. We propose a modular natural language processing pipeline for mapping (normalizing) colloquial mentions of ADRs to their corresponding standardized identifiers. We seek to accomplish this task and enable customization of the pipeline so that distinct unlabeled free text resources can be incorporated to use the system for other normalization tasks. Our approach, which we call Hybrid Semantic Analysis (HSA), sequentially employs rule-based and semantic matching algorithms for mapping user-generated mentions to concept IDs in the Unified Medical Language System vocabulary. The semantic matching component of HSA is adaptive in nature and uses a regression model to combine various measures of semantic relatedness and resources to optimize normalization performance on the selected data source. On a publicly available corpus, our normalization method achieves 0.502 recall and 0.823 precision (F-measure: 0.624). Our proposed method outperforms a baseline based on latent semantic analysis and another that uses MetaMap.

B. subtilis as a Model for Studying the Assembly of Fe-S Clusters in Gram-Positive Bacteria.

PubMed

Dos Santos, Patricia C

2017-01-01

Complexes of iron and sulfur (Fe-S clusters) are widely distributed in nature and participate in essential biochemical reactions. The biological formation of Fe-S clusters involves dedicated pathways responsible for the mobilization of sulfur, the assembly of Fe-S clusters, and the transfer of these clusters to target proteins. Genomic analysis of Bacillus subtilis and other Gram-positive bacteria indicated the presence of only one Fe-S cluster biosynthesis pathway, which is distinct in number of components and organization from previously studied systems. B. subtilis has been used as a model system for the characterization of cysteine desulfurases responsible for sulfur mobilization reactions in the biogenesis of Fe-S clusters and other sulfur-containing cofactors. Cysteine desulfurases catalyze the cleavage of the C-S bond from the amino acid cysteine and subsequent transfer of sulfur to acceptor molecules. These reactions can be monitored by the rate of alanine formation, the first product in the reaction, and sulfide formation, a byproduct of reactions performed under reducing conditions. The assembly of Fe-S clusters on protein scaffolds and the transfer of these clusters to target acceptors are determined through a combination of spectroscopic methods probing the rate of cluster assembly and transfer. This chapter provides a description of reactions promoting the assembly of Fe-S clusters in bacteria as well as methods used to study functions of each biosynthetic component and identify mechanistic differences employed by these enzymes across different pathways. © 2017 Elsevier Inc. All rights reserved.

Metabolomic Analysis of Key Central Carbon Metabolism Carboxylic Acids as Their 3-Nitrophenylhydrazones by UPLC/ESI-MS

PubMed Central

Han, Jun; Gagnon, Susannah; Eckle, Tobias; Borchers, Christoph H.

2014-01-01

Multiple hydroxy-, keto-, di-, and tri-carboxylic acids are among the cellular metabolites of central carbon metabolism (CCM). Sensitive and reliable analysis of these carboxylates is important for many biological and cell engineering studies. In this work, we examined 3-nitrophenylhydrazine as a derivatizing reagent and optimized the reaction conditions for the measurement of ten CCM related carboxylic compounds, including glycolate, lactate, malate, fumarate, succinate, citrate, isocitrate, pyruvate, oxaloacetate, and α-ketoglutarate as their 3-nitrophenylhydrazones using LC/MS with electrospray ionization. With the derivatization protocol which we have developed, and using negative-ion multiple reaction monitoring on a triple-quadrupole instrument, all of the carboxylates showed good linearity within a dynamic range of ca. 200 to more than 2000. The on-column limits of detection and quantitation were from high femtomoles to low picomoles. The analytical accuracies for eight of the ten analytes were determined to be between 89.5 to 114.8% (CV≤7.4%, n=6). Using a quadrupole time-of-flight instrument, the isotopic distribution patterns of these carboxylates, extracted from a 13C-labeled mouse heart, were successfully determined by UPLC/MS with full-mass detection, indicating the possible utility of this analytical method for metabolic flux analysis. In summary, this work demonstrates an efficient chemical derivatization LC/MS method for metabolomic analysis of these key CCM intermediates in a biological matrix. PMID:23580203

New Web-Monitoring Service Worries Some Legal Experts

ERIC Educational Resources Information Center

Sander, Libby

2008-01-01

A software program that searches for offensive content on college athletes' social-networking sites has drawn skeptical reactions from legal experts, who say it could threaten students' constitutional rights. Billed as a "social-network monitoring service" and marketed exclusively to college athletics departments, YouDiligence was on display at…

40 CFR 258.54 - Detection monitoring program.

Code of Federal Regulations, 2014 CFR

2014-07-01

... FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.54 Detection... indicator parameters for a MSWLF unit, in lieu of some or all of the heavy metals (constituents 1-15 in... parameters, waste constituents, and reaction products in the ground water; and (iv) The concentration or...

40 CFR 258.54 - Detection monitoring program.

Code of Federal Regulations, 2013 CFR

2013-07-01

... FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.54 Detection... indicator parameters for a MSWLF unit, in lieu of some or all of the heavy metals (constituents 1-15 in... parameters, waste constituents, and reaction products in the ground water; and (iv) The concentration or...

40 CFR 258.54 - Detection monitoring program.

Code of Federal Regulations, 2012 CFR

2012-07-01

... FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.54 Detection... indicator parameters for a MSWLF unit, in lieu of some or all of the heavy metals (constituents 1-15 in... parameters, waste constituents, and reaction products in the ground water; and (iv) The concentration or...

40 CFR 258.54 - Detection monitoring program.

Code of Federal Regulations, 2011 CFR

2011-07-01

... FOR MUNICIPAL SOLID WASTE LANDFILLS Ground-Water Monitoring and Corrective Action § 258.54 Detection... indicator parameters for a MSWLF unit, in lieu of some or all of the heavy metals (constituents 1-15 in... parameters, waste constituents, and reaction products in the ground water; and (iv) The concentration or...

MONITORING ASPERGILLUS SPECIES BY QUANTITATIVE PCR DURING CONSTRUCTION OF A MULTI-STORY HOSPITAL BUILDING

EPA Science Inventory

Noscomial fungal infections represent a persistent threat in hospitals. One of the major issues in fungal control has been monitoring these fungi in a timely manner. Quantitative polymerase chain reaction (QPCR) allows for the rapid (2 to 4 h), sensitive (often down to a single...

An Optical Biosensing Strategy Based on Selective Light Absorption and Wavelength Filtering from Chromogenic Reaction.

PubMed

Chun, Hyeong Jin; Han, Yong Duk; Park, Yoo Min; Kim, Ka Ram; Lee, Seok Jae; Yoon, Hyun C

2018-03-06

To overcome the time and space constraints in disease diagnosis via the biosensing approach, we developed a new signal-transducing strategy that can be applied to colorimetric optical biosensors. Our study is focused on implementation of a signal transduction technology that can directly translate the color intensity signals-that require complicated optical equipment for the analysis-into signals that can be easily counted with the naked eye. Based on the selective light absorption and wavelength-filtering principles, our new optical signaling transducer was built from a common computer monitor and a smartphone. In this signal transducer, the liquid crystal display (LCD) panel of the computer monitor served as a light source and a signal guide generator. In addition, the smartphone was used as an optical receiver and signal display. As a biorecognition layer, a transparent and soft material-based biosensing channel was employed generating blue output via a target-specific bienzymatic chromogenic reaction. Using graphics editor software, we displayed the optical signal guide patterns containing multiple polygons (a triangle, circle, pentagon, heptagon, and 3/4 circle, each associated with a specified color ratio) on the LCD monitor panel. During observation of signal guide patterns displayed on the LCD monitor panel using a smartphone camera via the target analyte-loaded biosensing channel as a color-filtering layer, the number of observed polygons changed according to the concentration of the target analyte via the spectral correlation between absorbance changes in a solution of the biosensing channel and color emission properties of each type of polygon. By simple counting of the changes in the number of polygons registered by the smartphone camera, we could efficiently measure the concentration of a target analyte in a sample without complicated and expensive optical instruments. In a demonstration test on glucose as a model analyte, we could easily measure the concentration of glucose in the range from 0 to 10 mM.

Validation of a thin-layer chromatography/densitometry method for the characterization of invertase activity.

PubMed

Ferey, Justine; Da Silva, David; Bravo-Veyrat, Sophie; Lafite, Pierre; Daniellou, Richard; Maunit, Benoît

2016-12-16

This paper presents a kinetic study of invertase, a specific fructofuranosidase cloned from the Leishmania major genome. The kinetic parameters of the β-d-fructofuranosidase from Leishmania major (BfrA) were determined using Thin-Layer Chromatography (TLC) and UV-densitometry (TLC@UV) specifically developed for the separation and detection of three carbohydrates namely sucrose, glucose and fructose. Separation was performed on TLC silica gel 60 F254 plates impregnated with sodium bisulphate and citrate and heated prior to development. This fast and easy separation was performed with two successive developments using ACN/H 2 O 80/20 (v/v) as mobile phase. Sensitive and repeatable derivatization of sugars was achieved by dipping the plates in a solution of 4-aminobenzoic acid. Quantification was performed by UV-detection. The method was validated according to ICH guidelines Q2(R1) in terms of specificity, limits of detection and quantification, precision and robustness (with n=3 replicates and CV ≤10%). The characterization of BfrA reaction kinetic was performed by monitoring the accumulation of either glucose or fructose detected by TLC@UV. Hydrolysis of sucrose was described by the Michaelis-Menten kinetic parameters (K M ; V max ) respectively equal to 63.09±7.590mM; 0.037±0.00094mM/min using glucose production and 83.01±14.39mM; 0.031±0.0021mM/min monitoring fructose. Hydrolyses of three alternative substrates, raffinose, stachyose and inulin, were also compared and the regiospecificity of the reaction was characterized. This TLC@UV method is shown to be suitable for the refined kinetic analysis of different reactions related to the hydrolysis of sugars. Copyright © 2016. Published by Elsevier B.V.

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

PubMed

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.

Catalytic Reduction of 4-Nitrophenol: A Quantitative Assessment of the Role of Dissolved Oxygen in Determining the Induction Time.

PubMed

Menumerov, Eredzhep; Hughes, Robert A; Neretina, Svetlana

2016-12-14

The reduction of 4-nitrophenol to 4-aminophenol by borohydride is one of the foremost model catalytic reactions because it allows for a straightforward assessment of catalysts using the kinetic parameters extracted from the real-time spectroscopic monitoring of an aqueous solution. Crucial to its standing as a model reaction is a comprehensive mechanistic framework able to explain the entire time evolution of the reaction. While much of this framework is in place, there is still much debate over the cause of the induction period, an initial time interval where no reaction seemingly occurs. Here, we report on the simultaneous monitoring of the spectroscopic signal and the dissolved oxygen content within the aqueous solution. It reveals that the induction period is the time interval required for the level of dissolved oxygen to fall below a critical value that is dependent upon whether Au, Ag, or Pd nanoparticles are used as the catalyst. With this understanding, we are able to exert complete control over the induction period, being able to eliminate it, extend it indefinitely, or even induce multiple induction periods over the course of a single reaction. Moreover, we have determined that the reaction product, 4-aminophenol, in the presence of the same catalyst reacts with dissolved oxygen to form 4-nitrophenolate. The implication of these results is that the induction period relates, not to some activation of the catalyst, but to a time interval where the reaction product is being rapidly transformed back into a reactant by a side reaction.

Removal of NO in NO/N2, NO/N2/O2, NO/CH4/N2, and NO/CH4/O2/N2 systems by flowing microwave discharges.

PubMed

Hueso, José L; Gonzalez-Elipe, Agustín R; Cotrino, José; Caballero, Alfonso

2007-02-15

In this paper, continuing previous work, we report on experiments carried out to investigate the removal of NO from simulated flue gas in nonthermal plasmas. The plasma-induced decomposition of small concentrations of NO in N2 used as the carrier gas and O2 and CH4 as minority components has been studied in a surface wave discharge induced with a surfatron launcher. The reaction products and efficiency have been monitored by mass spectrometry as a function of the composition of the mixture. NO is effectively decomposed into N2 and O2 even in the presence of O2, provided always that enough CH4 is also present in the mixture. Other majority products of the plasma reactions under these conditions are NH3, CO, and H2. In the absence of O2, decomposition of NO also occurs, although in that case HCN accompanies the other reaction products as a majority component. The plasma for the different reaction mixtures has been characterized by optical emission spectroscopy. Intermediate excited species of NO*, C*, CN*, NH*, and CH* have been monitored depending on the gas mixture. The type of species detected and their evolution with the gas composition are in agreement with the reaction products detected in each case. The observations by mass spectrometry and optical emission spectroscopy are in agreement with the kinetic reaction models available in literature for simple plasma reactions in simple reaction mixtures.

CH3CO + O2 + M (M = He, N2) Reaction Rate Coefficient Measurements and Implications for the OH Radical Product Yield.

PubMed

Papadimitriou, Vassileios C; Karafas, Emmanuel S; Gierczak, Tomasz; Burkholder, James B

2015-07-16

The gas-phase CH3CO + O2 reaction is known to proceed via a chemical activation mechanism leading to the formation of OH and CH3C(O)OO radicals via bimolecular and termolecular reactive channels, respectively. In this work, rate coefficients, k, for the CH3CO + O2 reaction were measured over a range of temperature (241-373 K) and pressure (0.009-600 Torr) with He and N2 as the bath gas and used to characterize the bi- and ter-molecular reaction channels. Three independent experimental methods (pulsed laser photolysis-laser-induced fluorescence (PLP-LIF), pulsed laser photolysis-cavity ring-down spectroscopy (PLP-CRDS), and a very low-pressure reactor (VLPR)) were used to characterize k(T,M). PLP-LIF was the primary method used to measure k(T,M) in the high-pressure regime under pseudo-first-order conditions. CH3CO was produced by PLP, and LIF was used to monitor the OH radical bimolecular channel reaction product. CRDS, a complementary high-pressure method, measured k(295 K,M) over the pressure range 25-600 Torr (He) by monitoring the temporal CH3CO radical absorption following its production via PLP in the presence of excess O2. The VLPR technique was used in a relative rate mode to measure k(296 K,M) in the low-pressure regime (9-32 mTorr) with CH3CO + Cl2 used as the reference reaction. A kinetic mechanism analysis of the combined kinetic data set yielded a zero pressure limit rate coefficient, kint(T), of (6.4 ± 4) × 10(-14) exp((820 ± 150)/T) cm(3) molecule(-1) s(-1) (with kint(296 K) measured to be (9.94 ± 1.3) × 10(-13) cm(3) molecule(-1) s(-1)), k0(T) = (7.39 ± 0.3) × 10(-30) (T/300)(-2.2±0.3) cm(6) molecule(-2) s(-1), and k∞(T) = (4.88 ± 0.05) × 10(-12) (T/300)(-0.85±0.07) cm(3) molecule(-1) s(-1) with Fc = 0.8 and M = N2. A He/N2 collision efficiency ratio of 0.60 ± 0.05 was determined. The phenomenological kinetic results were used to define the pressure and temperature dependence of the OH radical yield in the CH3CO + O2 reaction. The present results are compared with results from previous studies and the discrepancies are discussed.

Changes in Choice Reaction Time During and After 8 Days Exhaustive Cycling Are Not Related to Changes in Physical Performance.

PubMed

Ten Haaf, Twan; van Staveren, Selma; Iannetta, Danilo; Roelands, Bart; Meeusen, Romain; Piacentini, Maria F; Foster, Carl; Koenderman, Leo; Daanen, Hein A M; de Koning, Jos J

2018-04-01

Reaction time has been proposed as a training monitoring tool, but to date, results are equivocal. Therefore, it was investigated whether reaction time can be used as a monitoring tool to establish overreaching. The study included 30 subjects (11 females and 19 males, age: 40.8 [10.8] years, VO 2max : 51.8 [6.3] mL/kg/min) who participated in an 8-day cycling event. The external exercise load increased approximately 900% compared with the preparation period. Performance was measured before and after the event using a maximal incremental cycling test. Subjects with decreased performance after the event were classified as functionally overreached (FOR) and others as acutely fatigued (AF). A choice reaction time test was performed 2 weeks before (pre), 1 week after (post), and 5 weeks after (follow-up), as well as at the start and end of the event. A total of 14 subjects were classified as AF and 14 as FOR (2 subjects were excluded). During the event, reaction time at the end was 68 ms (95% confidence interval, 46-89) faster than at the start. Reaction time post event was 41 ms (95% confidence interval, 12-71) faster than pre event and follow-up was 55 ms faster (95% confidence interval, 26-83). The time by class interaction was not significant during (P = .26) and after (P = .43) the event. Correlations between physical performance and reaction time were not significant (all Ps > .30). No differences in choice reaction time between AF and FOR subjects were observed. It is suggested that choice reaction time is not valid for early detection of overreaching in the field.

Nucleophilic Substitution Reactions Using Phosphine Nucleophiles: An Introduction to Phosphorus-31 NMR

ERIC Educational Resources Information Center

Sibbald, Paul A.

2015-01-01

Nuclear magnetic resonance (NMR) spectroscopy is commonly used in modern synthetic chemistry to monitor the conversion of reactants to products. Since instruction in the use of NMR spectroscopy typically does not occur until after the introduction of nucleophilic substitution reactions, organic chemistry students are not able to take advantage of…

A Fluorogenic Aromatic Nucleophilic Substitution Reaction for Demonstrating Normal-Phase Chromatography and Isolation of Nitrobenzoxadiazole Chromophores

ERIC Educational Resources Information Center

Key, Jessie A.; Li, Matthew D.; Cairo, Christopher W.

2011-01-01

Normal-phase chromatography is an essential technique for monitoring chemical reactions, identifying the presence of specific components, as well as the purification of organic compounds. An experiment to facilitate the instruction and understanding of the concepts behind normal-phase chromatography at the introductory and intermediate…

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

PubMed

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.

Palliative effects of H2 on SOFCs operating with carbon containing fuels

NASA Astrophysics Data System (ADS)

Reeping, Kyle W.; Bohn, Jessie M.; Walker, Robert A.

2017-12-01

Chlorine can accelerate degradation of solid oxide fuel cell (SOFC) Ni-based anodes operating on carbon containing fuels through several different mechanisms. However, supplementing the fuel with a small percentage of excess molecular hydrogen effectively masks the degradation to the catalytic activity of the Ni and carbon fuel cracking reaction reactions. Experiments described in this work explore the chemistry behind the "palliative" effect of hydrogen on SOFCs operating with chlorine-contaminated, carbon-containing fuels using a suite of independent, complementary techniques. Operando Raman spectroscopy is used to monitor carbon accumulation and, by inference, Ni catalytic activity while electrochemical techniques including electrochemical impedance spectroscopy and voltammetry are used to monitor overall cell performance. Briefly, hydrogen not only completely hides degradation observed with chlorine-contaminated carbon-containing fuels, but also actively removes adsorbed chlorine from the surface of the Ni, allowing for the methane cracking reaction to continue, albeit at a slower rate. When hydrogen is removed from the fuel stream the cell fails immediately due to chlorine occupation of methane/biogas reaction sites.