WorldWideScience

Sample records for calorimetry

  1. Isothermal titration calorimetry.

    Science.gov (United States)

    Lewis, Edwin A; Murphy, Kenneth P

    2005-01-01

    Isothermal titration calorimetry is an ideal technique for measuring biological binding interactions. It does not rely on the presence of chromophores or fluorophores, nor does it require an enzymatic assay. Because the technique relies only on the detection of a heat effect upon binding, it can be used to measure the binding constant, K, the enthalpy of binding, DeltaH degrees and the stoichiometry, or number of binding sites, n. This chapter describes instrumentation, experimental design, and the theoretical underpinnings necessary to run and analyze a calorimetric binding experiment.

  2. Dual-readout Calorimetry

    CERN Document Server

    Akchurin, N; Cardini, A.; Cascella, M.; Cei, F.; De Pedis, D.; Fracchia, S.; Franchino, S.; Fraternali, M.; Gaudio, G.; Genova, P.; Hauptman, J.; La Rotonda, L.; Lee, S.; Livan, M.; Meoni, E.; Moggi, A.; Pinci, D.; Policicchio, A.; Saraiva, J.G.; Sill, A.; Venturelli, T.; Wigmans, R.

    2013-01-01

    The RD52 Project at CERN is a pure instrumentation experiment whose goal is to un- derstand the fundamental limitations to hadronic energy resolution, and other aspects of energy measurement, in high energy calorimeters. We have found that dual-readout calorimetry provides heretofore unprecedented information event-by-event for energy resolution, linearity of response, ease and robustness of calibration, fidelity of data, and particle identification, including energy lost to binding energy in nuclear break-up. We believe that hadronic energy resolutions of {\\sigma}/E $\\approx$ 1 - 2% are within reach for dual-readout calorimeters, enabling for the first time comparable measurement preci- sions on electrons, photons, muons, and quarks (jets). We briefly describe our current progress and near-term future plans. Complete information on all aspects of our work is available at the RD52 website http://highenergy.phys.ttu.edu/dream/.

  3. Calorimetry at industrial electron accelerators

    DEFF Research Database (Denmark)

    Miller, Arne; Kovacs, A.

    1985-01-01

    Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials such as grap......Calorimetry is a convenient way to measure doses at industrial electron accelerators, where high absorbed doses (1-100 kGy) are delivered at dose rates of 102-105 Gy s-1 or even higher. Water calorimeters have been used for this purpose for several years, but recently other materials...

  4. Calorimetry fundamentals, instrumentation and applications

    CERN Document Server

    Sarge, Stefan M; Hemminger, Wolfgang

    2014-01-01

    Clearly divided into three parts, this practical book begins by dealing with all fundamental aspects of calorimetry. The second part looks at the equipment used and new developments. The third and final section provides measurement guidelines in order to obtain the best results. The result is optimized knowledge for users of this technique, supplemented with practical tips and tricks.

  5. CDF II integrated calorimetry environment

    CERN Document Server

    Dell'Agnello, S

    2002-01-01

    The Run IIa integrated calorimetry environment of CDF II comprises: sampling scintillator calorimeters, e.m. preshower and shower-maximum detectors (gas based in the central, scintillator based in the forward), crack-filler detectors, radioactive source calibration systems, light pulse calibration systems, dedicated triggers for critical low energy calibrations, new FEE, a Windows NT slow control system, the master online-offline Oracle Database and an online data validation framework, distilled over the previous years of CDF data taking (now based on the CERN Root). The preexisting central calorimeters are the bridge between the energy and time measurement of the past and current physics runs. New forward calorimeters (the "plugs"), built with the modern scintillating tile-fiber technique, replaced the old gas calorimeters. Together they form an integrated, general-purpose calorimetry system which has been successfully commissioned with the 2000-2001 collider data. The time measurement, before present only i...

  6. ceramics by differential scanning calorimetry

    Indian Academy of Sciences (India)

    Administrator

    YbxGd2–xZr2O7 (x = 0, 1, 2) ceramics were pressureless-sintered using ceramic powders acquired by chemical-coprecipitation and calcination methods. Heat capacities of YbxGd2–xZr2O7 were measured with a heat flux-type differential scanning calorimetry in the temperature range of 298–1200 K. At 298 K, the heat.

  7. Isothermal Titration Calorimetry of RNA

    OpenAIRE

    Salim, Nilshad N.; Feig, Andrew L.

    2008-01-01

    Isothermal titration calorimetry (ITC) is a fast and robust method to study the physical basis of molecular interactions. A single well-designed experiment can provide complete thermodynamic characterization of a binding reaction, including Ka, ΔG, ΔH, ΔS and reaction stoichiometry (n). Repeating the experiment at different temperatures allows determination of the heat capacity change (ΔCP) of the interaction. Modern calorimeters are sensitive enough to probe even weak biological interactions...

  8. Indirect calorimetry during incubation of hatching eggs

    NARCIS (Netherlands)

    Brand, van den H.; Heetkamp, M.J.W.; Kemp, B.

    2015-01-01

    Indirect calorimetry can be used during incubation of avian eggs to monitor the quality of the incubation process, the development of the embryo and the utilization of nutrients. Indirect calorimetry has several benefits above direct calorimetry, particularly in hatching eggs. However, to obtain

  9. Calorimetry of non-reacting systems

    CERN Document Server

    McCullough, John P

    2013-01-01

    Experimental Thermodynamics, Volume 1: Calorimetry of Non-Reacting Systems covers the heat capacity determinations for chemical substances in the solid, liquid, solution, and vapor states, at temperatures ranging from near the absolute zero to the highest at which calorimetry is feasible.This book is divided into 14 chapters. The first four chapters provide background information and general principles applicable to all types of calorimetry of non-reacting systems. The remaining 10 chapters deal with specific types of calorimetry. Most of the types of calorimetry treated are developed over a c

  10. Isothermal titration calorimetry of RNA.

    Science.gov (United States)

    Salim, Nilshad N; Feig, Andrew L

    2009-03-01

    Isothermal titration calorimetry (ITC) is a fast and robust method to study the physical basis of molecular interactions. A single well-designed experiment can provide complete thermodynamic characterization of a binding reaction, including K(a), DeltaG, DeltaH, DeltaS and reaction stoichiometry (n). Repeating the experiment at different temperatures allows determination of the heat capacity change (DeltaC(P)) of the interaction. Modern calorimeters are sensitive enough to probe even weak biological interactions making ITC a very popular method among biochemists. Although ITC has been applied to protein studies for many years, it is becoming widely applicable in RNA biochemistry as well, especially in studies which involve RNA folding and RNA interactions with small molecules, proteins and with other RNAs. This review focuses on best practices for planning, designing and executing effective ITC experiments when one or more of the reactants is an RNA.

  11. Development of Quartz Fiber Calorimetry

    CERN Multimedia

    2002-01-01

    % RD40 \\\\ \\\\ Very Forward Calorimeters (VFCs) in LHC detectors should cover the pseudorapidity range from $\\eta$~=~2.5 to at least $\\eta$~=~5 in order to compute missing transverse energy and for jet tagging. Operation at such high rapidity requires the use of a calorimetry technique that is very radiation resistant, fast and insensitive to radioactivity (especially to neutrons). This can be accomplished through the Quartz-Calorimeter~(Q-Cal) concept of embedding silica core fibers, that resist to the Gigarad radiation level, into an absorber. In this calorimeter the shower particles produce light through the Cherenkov effect generating a signal less than 10~ns in duration. Unique to this new technology the visible energy of hadronic showers has a transverse dimension nearly an order of magnitude smaller than that in conventional calorimeters, enabling precise spatial resolution, sharper isolation cuts and better jet recognition against the minimum bias events background. Last but not least, most radioactive ...

  12. Recent Work on Calorimetry at LANL

    Energy Technology Data Exchange (ETDEWEB)

    Santi, Peter A. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Hauck, Danielle K. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2014-01-09

    This report is a briefing to collaborators at the Swedish Nuclear Fuel and Waste Management Company, Oskarshamn, Sweden, January 14, 2014. It describes the way in which calorimetry supports the safegurard mission.

  13. Calorimetry energy measurement in particle physics

    CERN Document Server

    Wigmans, Richard

    2017-01-01

    Particle physics is the science that pursues the age-old quest for the innermost structure of matter and the fundamental interactions between its constituents. Modern experiments in this field rely increasingly on calorimetry, a detection technique in which the particles of interest are absorbed in the detector. Calorimeters are very intricate instruments. Their performance characteristics depend on subtle, sometimes counter-intuitive design details. This book, written by one of the world's foremost experts, is the first comprehensive text on this topic. It provides a fundamental and systematic introduction to calorimetry. It describes the state of the art in terms of both the fundamental understanding of calorimetric particle detection, and the actual detectors that have been or are being built and operated in experiments. The last chapter discusses landmark scientific discoveries in which calorimetry has played an important role. This book summarizes and puts into perspective the work described in some 900...

  14. Calorimetry at a Future Linear Collider

    CERN Document Server

    AUTHOR|(CDS)2090195; Marshall, John

    This thesis describes the optimisation of the calorimeter design for collider experiments at the future Compact LInear Collider (CLIC) and the International Linear Collider (ILC). The detector design of these experiments is built around high-granularity Particle Flow Calorimetry that, in contrast to traditional calorimetry, uses the energy measurements for charged particles from the tracking detectors. This can only be realised if calorimetric energy deposits from charged particles can be separated from those of neutral particles. This is made possible with fine granularity calorimeters and sophisticated pattern recognition software, which is provided by the PandoraPFA algorithm. This thesis presents results on Particle Flow calorimetry performance for a number of detector configurations. To obtain these results a new calibration procedure was developed and applied to the detector simulation and reconstruction to ensure optimal performance was achieved for each detector configuration considered. This thesis a...

  15. Calorimetry and thermal methods in catalysis

    CERN Document Server

    Auroux, Aline

    2013-01-01

    The book is about calorimetry and thermal analysis methods, alone or linked to other techniques, as applied to the characterization of catalysts, supports and adsorbents, and to the study of catalytic reactions in various domains: air and wastewater treatment, clean and renewable energies, refining of hydrocarbons, green chemistry, hydrogen production and storage. The book is intended to fill the gap between the basic thermodynamic and kinetics concepts acquired by students during their academic formation, and the use of experimental techniques such as thermal analysis and calorimetry to answ

  16. Microwave calorimetry using X-rays

    Energy Technology Data Exchange (ETDEWEB)

    Nicula, R., E-mail: radu.nicula@empa.ch [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Stir, M. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Wurm, A. [University of Rostock, Institute of Physics, Wismarsche Str. 43-45, 18051 Rostock (Germany); Catala-Civera, J.M. [Universidad Politecnica de Valencia, Camino Vera s/n, E-46022 Valencia (Spain); Ishizaki, K.; Vaucher, S. [Empa, Swiss Federal Laboratories for Materials Science and Technology, Advanced Materials Processing, Feuerwerkerstr. 39, CH-3602 Thun (Switzerland); Zhuravlev, E.; Schick, C. [University of Rostock, Institute of Physics, Wismarsche Str. 43-45, 18051 Rostock (Germany)

    2011-11-10

    Highlights: Black-Right-Pointing-Pointer New approach for microwave calorimetry using synchrotron radiation powder diffraction. Black-Right-Pointing-Pointer In situ monitoring of the magnetostructural transformation of Co under magnetic microwave heating at 2.45 GHz. Black-Right-Pointing-Pointer Magnetic heat capacity of Co due to the spin-reorientation transition at microwave frequencies. - Abstract: An alternative approach for microwave calorimetry is proposed which relies on the synchrotron radiation powder diffraction technique as well as on the Grueneisen formalism for the analysis of thermal expansion. Cobalt was selected as suitable magnetic material for the present evaluation of the method. First results are reported concerning the calorimetric assessment of the HCP (hexagonal close-packed) to FCC (face centered cubic) transition of cobalt from in situ time-resolved X-ray diffraction experiments performed during magnetic (H-field) microwave heating. The X-ray calorimetry method yields specific heat capacity estimations that compare well with results from conventional differential scanning calorimetry measurements. In the presence of the 2.45 GHz microwave H-field, an 'anomalous' behaviour of the heat capacity across the structural phase transition is detected, which can be correlated with the magnetic spin reorientation transition of cobalt in the same temperature range.

  17. Study of asphaltene precipitation by Calorimetry

    DEFF Research Database (Denmark)

    Verdier, Sylvain Charles Roland; Plantier, Frédéric; Bessières, David

    2007-01-01

    of experiments showed that weak forces determine precipitation. Indeed, isothermal titration calorimetry could not detect any clear signal although this technique can detect low-energy transitions such as liquid-liquid equilibrium and rnicellization. The second series of tests proved that precipitation caused...

  18. Monte Carlo studies of uranium calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Brau, J.; Hargis, H.J.; Gabriel, T.A.; Bishop, B.L.

    1985-01-01

    Detailed Monte Carlo calculations of uranium calorimetry are presented which reveal a significant difference in the responses of liquid argon and plastic scintillator in uranium calorimeters. Due to saturation effects, neutrons from the uranium are found to contribute only weakly to the liquid argon signal. Electromagnetic sampling inefficiencies are significant and contribute substantially to compensation in both systems. 17 references.

  19. Calculation of Temperature Rise in Calorimetry.

    Science.gov (United States)

    Canagaratna, Sebastian G.; Witt, Jerry

    1988-01-01

    Gives a simple but fuller account of the basis for accurately calculating temperature rise in calorimetry. Points out some misconceptions regarding these calculations. Describes two basic methods, the extrapolation to zero time and the equal area method. Discusses the theoretical basis of each and their underlying assumptions. (CW)

  20. Isothermal Titration Calorimetry in the Student Laboratory

    Science.gov (United States)

    Wadso, Lars; Li, Yujing; Li, Xi

    2011-01-01

    Isothermal titration calorimetry (ITC) is the measurement of the heat produced by the stepwise addition of one substance to another. It is a common experimental technique, for example, in pharmaceutical science, to measure equilibrium constants and reaction enthalpies. We describe a stirring device and an injection pump that can be used with a…

  1. Analyzing Protein Denaturation using Fast Differential Scanning Calorimetry

    NARCIS (Netherlands)

    Splinter, R.; Van Herwaarden, A.W.; Iervolino, E.; Vanden Poel, G.; Istrate, D.; Sarro, P.M.

    2012-01-01

    This paper investigates the possibility to measure protein denaturation with Fast Differential Scanning Calorimetry (FDSC). Cancer can be diagnosed by measuring protein denaturation in blood plasma using Differential Scanning Calorimetry (DSC). FDSC can reduce diagnosis time from hours to minutes,

  2. Analysis of Cooperativity by Isothermal Titration Calorimetry

    Directory of Open Access Journals (Sweden)

    Alan Brown

    2009-08-01

    Full Text Available Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of cooperative systems.

  3. Analysis of cooperativity by isothermal titration calorimetry.

    Science.gov (United States)

    Brown, Alan

    2009-08-04

    Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of cooperative systems.

  4. Analysis of Cooperativity by Isothermal Titration Calorimetry

    OpenAIRE

    Brown, Alan

    2009-01-01

    Cooperative binding pervades Nature. This review discusses the use of isothermal titration calorimetry (ITC) in the identification and characterisation of cooperativity in biological interactions. ITC has broad scope in the analysis of cooperativity as it determines binding stiochiometries, affinities and thermodynamic parameters, including enthalpy and entropy in a single experiment. Examples from the literature are used to demonstrate the applicability of ITC in the characterisation of coop...

  5. Calibration and monitoring for crystal calorimetry

    CERN Document Server

    Zhu, Ren Yuan

    2005-01-01

    Crystal calorimetry provides excellent energy resolution in high energy and nuclear physics. The light output of heavy crystal scintillators, however, suffers from not negligible damage in radiation environment. A precision calibration and monitoring thus is crucial for maintaining crystal precision in situ. The performance of calibration and monitoring approaches used by BaBar, CLEO and L3 experiments are presented. The design and construction of a laser- based light monitoring system for CMS PWO calorimeter is also discussed.

  6. Calorimetry and thermodynamics of living systems

    Energy Technology Data Exchange (ETDEWEB)

    Lamprecht, Ingolf

    2003-10-14

    Calorimetry of living systems and classical thermodynamics developed in parallel, from Lavoisier's early ice calorimeter experiments on guinea pigs, followed by Dubrunfaut's macrocalorimetric research of fermentation processes and Atwater-Rosa's whole-body calorimetry on humans and domestic animals, to the introduction of the famous Tian-Calvet instrument that found entrance into so many different fields of biology. In this work, six examples of living-system calorimetry and thermodynamics are presented. These are: (i) glycolytic oscillations far off the thermodynamic equilibrium; (ii) growth and energy balances in fermenting and respiring yeast cultures; (iii) direct and indirect calorimetric monitoring of electrically stimulated reptile metabolism; (iv) biologic and climatic factors influencing the temperature constancy and distribution in the mound of a wood ant colony as an example of a complex ecological system; (v) energetic considerations on the clustering of European honeybees in winter as a means to save energy and stored food as well as for their Japanese counterparts in defending against hornet predators; and (vi) energetic and evolutionary aspects of the mass specific entropy production rate, the so-called bound dissipation or psiu-function. The examples presented here are just a very personal selection of living systems from a broad spectrum at all levels of complexity. Common for all of them is that they were investigated calorimetrically on the background of classical and irreversible thermodynamics.

  7. Scintillating Fibre Calorimetry at the LHC

    CERN Multimedia

    2002-01-01

    Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. The lead/scintillating fibre calorimeter technique provides a fast signal response well matched to the LHC rate requirements. It can be made to give equal response for electrons and hadrons (compensation) with good electromagnetic and hadronic energy resolutions.\\\\ \\\\ The aim of this R&D proposal is to study in detail the aspects that are relevant for application of this type of calorimeter in an LHC environment, including its integration in a larger system of detectors, e.g.~projective geometry, radiation hardness, light detection, calibration and stability monitoring, electron/hadron separation.....

  8. Calorimetry of the CMD-3 detector

    Science.gov (United States)

    Shebalin, V. E.; Akhmetshin, R. R.; Anisenkov, A. V.; Aulchenko, V. M.; Bashtovoy, N. S.; Epifanov, D. A.; Epshteyn, L. B.; Erofeev, A. L.; Grebenuk, A. A.; Grigoriev, D. N.; Ignatov, F. V.; Kazanin, V. F.; Kovalenko, O. A.; Kozyrev, A. N.; Kuzmenko, A. E.; Kuzmin, A. S.; Logashenko, I. B.; Mikhailov, K. Yu.; Okhapkin, V. S.; Razuvaev, G. P.; Ruban, A. A.; Shwartz, B. A.; Titov, V. M.; Talyshev, A. A.; Yudin, Yu. V.

    2016-07-01

    CMD-3 is a general purpose detector designed to study e+e- annihilation into hadrons. It is mounted at VEPP-2000 collider which operates in the wide energy range, E c . m . s = 0.32 - 2 GeV. The calorimetry at the detector is based on three subsystems: closest to the beam pipe barrel Liquid Xenon calorimeter, outer barrel calorimeter based on CsI scintillation crystals and the endcap calorimeter made of BGO scintillation crystals. We describe the structure of the calorimeters, their electronics and the energy calibration procedures.

  9. G-2 and CMS fast optical calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Winn, David R.

    2001-06-01

    The following projects are discussed: (A) Operation of the muon g-2 experiment at Brookhaven National Lab (Experiment E821), especially the pulsed laser calibration system, to test the standard model of forces, and to see if new forces may exist in the vacuum. (B) The second part of this project developed fast optical forward Cerenkov jet calorimetry used in the CMS experiment collaboration (US lead organization FermiLab) at CERN on the Large Hadron Collider, designed to detect new physics at the TeV scale, such as supersymmetry and the Higgs boson.

  10. Imaging hadron calorimetry for future Lepton Colliders

    Energy Technology Data Exchange (ETDEWEB)

    Repond, José, E-mail: repond@hep.anl.gov

    2013-12-21

    To fully exploit the physics potential of a future Lepton Collider requires detectors with unprecedented jet energy and dijet-mass resolution. To meet these challenges, detectors optimized for the application of Particle Flow Algorithms (PFAs) are being designed and developed. The application of PFAs, in turn, requires calorimeters with very fine segmentation of the readout, so-called imaging calorimeters. This talk reviews progress in imaging hadron calorimetry as it is being developed for implementation in a detector at a future Lepton Collider. Recent results from the large prototypes built by the CALICE Collaboration, such as the Scintillator Analog Hadron Calorimeter (AHCAL) and the Digital Hadron Calorimeters (DHCAL and SDHCAL) are being presented. In addition, various R and D efforts beyond the present prototypes are being discussed.

  11. Imaging hadron calorimetry for future Lepton Colliders

    Science.gov (United States)

    Repond, José

    2013-12-01

    To fully exploit the physics potential of a future Lepton Collider requires detectors with unprecedented jet energy and dijet-mass resolution. To meet these challenges, detectors optimized for the application of Particle Flow Algorithms (PFAs) are being designed and developed. The application of PFAs, in turn, requires calorimeters with very fine segmentation of the readout, so-called imaging calorimeters. This talk reviews progress in imaging hadron calorimetry as it is being developed for implementation in a detector at a future Lepton Collider. Recent results from the large prototypes built by the CALICE Collaboration, such as the Scintillator Analog Hadron Calorimeter (AHCAL) and the Digital Hadron Calorimeters (DHCAL and SDHCAL) are being presented. In addition, various R&D efforts beyond the present prototypes are being discussed.

  12. Particle Flow Calorimetry for the ILC

    Science.gov (United States)

    Magill, Stephen

    2006-04-01

    The Particle Flow approach to detector design is seen as the best way to achieve dijet mass resolutions suitable for the precision measurements anticipated at a future e^+e^- Linear Collider (LC). Particle Flow Algorithms (PFAs) affect not only the way data is analyzed, but are necessary and crucial elements used even in initial stages of detector design. In particular, the Calorimeter design parameters are almost entirely dependent on the optimized performance of the PFA. Use of PFAs imposes constraints on the granularity and segmentation of the readout cells, the choices of absorber and active media, and overall detector parameters such as the strength of the B-field, magnet bore, hermeticity, etc. PFAs must be flexible and modular in order to evaluate many detector models in simulation. The influence of PFA development on calorimetry is presented here with particular emphasis on results from the use of PFAs on several LC detector models.

  13. Isothermal calorimetry on enzymatic biodiesel production

    DEFF Research Database (Denmark)

    Fjerbæk, Lene

    2008-01-01

    information about effects taking place when using lipases immobilized on an inert carrier for transesterification of a triglyceride and an alcohol as for biodiesel production. The biodiesel is produced by rapeseed oil and methanol as well as ethanol and a commercial biocatalyst Novozym 435 from Novozymes...... containing a Candida Antarctica B lipase immobilized on an acrylic resin. The reaction investigated is characterized by immiscible liquids (oil, methanol, glycerol and biodiesel) and enzymes imm. on an inert carrier during reaction, which allows several effects to take place that during normal reaction...... conditions can not be elucidated. These effects have been observed with isothermal calorimetry bringing forth new information about the reaction of enzymes catalyzing transesterification. Enzymatic biodiesel production has until now not been investigated with isothermal microcalorimetry, but the results...

  14. Isothermal titration calorimetry of supramolecular polymers.

    Science.gov (United States)

    Arnaud, Alix; Bouteiller, Laurent

    2004-08-03

    A method to characterize the self-association of supramolecular polymers by isothermal titration calorimetry (ITC) has been designed. Association constants in the range 10(4)-10(6) dm(3) mol(-1) have been successfully determined from the heat exchange occurring when a supramolecular polymer solution is injected into a calorimetric cell containing pure solvent. Very good agreement with literature values has been obtained. Compared to other techniques (such as NMR or Fourier transform infrared spectroscopy), the use of ITC presents several advantages: (i) the enthalpy of association is obtained together with the association constant from the same experiment, (ii) the measurements can be performed in almost any solvent, and (iii) systems with higher association constants can be characterized.

  15. A "release" protocol for isothermal titration calorimetry.

    Science.gov (United States)

    Heerklotz, H H; Binder, H; Epand, R M

    1999-05-01

    Isothermal titration calorimetry (ITC) has become a standard method for investigating the binding of ligands to receptor molecules or the partitioning of solutes between water and lipid vesicles. Accordingly, solutes are mixed with membranes (or ligands with receptors), and the subsequent heats of incorporation (or binding) are measured. In this paper we derive a general formula for modeling ITC titration heats in both binding and partitioning systems that allows for the modeling of the classic incorporation or binding protocols, as well as of new protocols assessing the release of solute from previously solute-loaded vesicles (or the dissociation of ligand/receptor complexes) upon dilution. One major advantage of a simultaneous application of the incorporation/binding and release protocols is that it allows for the determination of whether a ligand is able to access the vesicle interior within the time scale of the ITC experiment. This information cannot be obtained from a classical partitioning experiment, but it must be known to determine the partition coefficient (or binding constant and stochiometry) and the transfer enthalpy. The approach is presented using the partitioning of the nonionic detergent C12EO7 to palmitoyloleoylphosphatidylcholine vesicles. The release protocol could also be advantageous in the case of receptors that are more stable in the ligand-saturated rather than the ligand-depleted state.

  16. Tissue ultrasound absorption measurement with MRI calorimetry.

    Science.gov (United States)

    Wang, Y; Hunt, J W; Foster, F S; Plewes, D B

    1999-01-01

    The renewed interest in the use of high intensity focused ultrasound (US) for minimally invasive magnetic resonance imaging (MRI)-guided thermal therapy has stimulated a review of the interaction mechanisms of US with tissue. Although the study of tissue US properties has been conducted extensively, agreements on the measured values of tissue US absorption are poor. We propose a noninvasive approach to measure tissue US absorption based on a form of MRI calorimetry. US absorption is measured in a small tissue sample through a knowledge of the US intensity distribution incident on the tissue and an MRI measurement of total absorbed energy arising from US exposure. US absorption measurements were conducted at room temperature for ex-vivo bovine liver tissue at 1 MHz, which led to a measured US absorption coefficient of 0.058 Np/cm or 0.504 dB/cm. Because this approach is noninvasive, the experimental complications exhibited in earlier studies are not present. Furthermore, this approach can be applied over a range of frequencies, tissues, and temperatures, which will aid in understanding of biothermal effects of high intensity US to improve thermal therapy.

  17. Indirect calorimetry: From bench to bedside

    Directory of Open Access Journals (Sweden)

    Riddhi Das Gupta

    2017-01-01

    Full Text Available Accurate determination of energy expenditure (EE is vitally important yet often neglected in clinical practice. Indirect calorimetry (IC provides one of the most sensitive, accurate, and noninvasive measurements of EE in an individual. Over the last couple of decades, this technique has been applied to clinical circumstances such as acute illness and parenteral nutrition. Beyond assessing the nutritional needs, it has also shed light on various aspects of nutrient assimilation, thermogenesis, the energetics of physical exercise, and the pathogenesis of obesity and diabetes. However, because of little or no experience with IC provided during medical education, the benefits of IC are poorly appreciated. Newer technology, cost-effectiveness, and a better understanding of how to interpret measurements should lead to more frequent use of IC. This review focuses on the physicochemical background of IC, the various indications for use, techniques and instruments, potential pitfalls in measurement, and the recent advances in technology that has adapted the technique to long-term studies in humans.

  18. Indirect Calorimetry: From Bench to Bedside.

    Science.gov (United States)

    Gupta, Riddhi Das; Ramachandran, Roshna; Venkatesan, Padmanaban; Anoop, Shajith; Joseph, Mini; Thomas, Nihal

    2017-01-01

    Accurate determination of energy expenditure (EE) is vitally important yet often neglected in clinical practice. Indirect calorimetry (IC) provides one of the most sensitive, accurate, and noninvasive measurements of EE in an individual. Over the last couple of decades, this technique has been applied to clinical circumstances such as acute illness and parenteral nutrition. Beyond assessing the nutritional needs, it has also shed light on various aspects of nutrient assimilation, thermogenesis, the energetics of physical exercise, and the pathogenesis of obesity and diabetes. However, because of little or no experience with IC provided during medical education, the benefits of IC are poorly appreciated. Newer technology, cost-effectiveness, and a better understanding of how to interpret measurements should lead to more frequent use of IC. This review focuses on the physicochemical background of IC, the various indications for use, techniques and instruments, potential pitfalls in measurement, and the recent advances in technology that has adapted the technique to long-term studies in humans.

  19. Homogeneous and isotropic calorimetry for space experiments

    Energy Technology Data Exchange (ETDEWEB)

    Mori, N., E-mail: mori@fi.infn.it [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Adriani, O. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); University of Florence, Department of Physics and Astronomy, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Basti, A. [INFN sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); Bigongiari, G. [University of Siena, Department of Physics, Earth and Environmental Sciences, Via Laterina 8, 53100 Siena (Italy); Bonechi, L. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Bonechi, S. [INFN sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); University of Siena, Department of Physics, Earth and Environmental Sciences, Via Laterina 8, 53100 Siena (Italy); Bongi, M. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); University of Florence, Department of Physics and Astronomy, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Bottai, S. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Brogi, P. [INFN sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); University of Siena, Department of Physics, Earth and Environmental Sciences, Via Laterina 8, 53100 Siena (Italy); D' Alessandro, R. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); University of Florence, Department of Physics and Astronomy, via G. Sansone 1, 50019 Sesto Fiorentino (Italy); Detti, S.; Lenzi, P. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); Maestro, P.; Marrocchesi, P.S. [INFN sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa (Italy); University of Siena, Department of Physics, Earth and Environmental Sciences, Via Laterina 8, 53100 Siena (Italy); Papini, P. [INFN sezione di Firenze, via B. Rossi 1, 50019 Sesto Fiorentino (Italy); and others

    2013-12-21

    Calorimetry plays an essential role in experiments observing high energy gamma and cosmic rays in space. The observational capabilities are mainly limited by the geometrical dimensions and the mass of the calorimeter. Since deployable mass depends on the design of the detector and the total mass of the payload, it is important to optimize the geometrical acceptance of the calorimeter for rare events, its granularity for particle identification, and its absorption depth for the measurement of the particle energy. A design of a calorimeter that could simultaneously optimize these characteristics assuming a mass limit of about 1.6 t has been studied. As a result, a homogeneous calorimeter instrumented with cesium iodide (CsI) crystals was chosen as the best compromise given the total mass constraint. The most suitable geometry found is cubic and isotropic, so as to detect particles arriving from every direction in space, thus maximizing the acceptance; granularity is obtained by filling the cubic volume with small cubic CsI crystals. The total radiation length in any direction is very large, and allows for optimal electromagnetic particle identification and energy measurement, while the interaction length is at least sufficient to allow a precise reconstruction of hadronic showers. Optimal values for the size of the crystals and spacing among them have been studied. Two prototypes have been constructed and preliminary tests with high energy ion and muon beams are reported.

  20. Isothermal Calorimetry for Biological Applications in Food Science and Technology

    OpenAIRE

    Wadsö, Lars; Gomez, Federico

    2009-01-01

    All physical, chemical and biological processes produce heat and isothermal calorimetry is a general measurement technique to study all kinds of processes by the heat they produce. This paper gives several examples of studies of biological processes in the food area using isothermal calorimetry. It is for example shown how different unit operations influence respiration of vegetable tissue, how the kinetics of a fermentation process can be studied, and how spoilage processes can be followed f...

  1. Thermal Analysis and Calorimetry Techniques for Catalytic Investigations

    Science.gov (United States)

    Le Parlouër, Pierre

    The use of thermal analysis and calorimetry techniques is quite an old and known field of applications for the catalytic investigations and many publications have been published on the various topics including analysis of catalysts, investigation of the processes during the preparation of catalysts, desactivation of catalysts and interaction of reactants or catalytic poisons with the catalysts. Differential thermal analysis, calorimetry and thermogravimetry are also used to characterize the catalysts, especially in the field of gas-solid and gas-liquid interactions. Since the last years, many technical improvements have appeared in the design and the use of thermal analyzers and calorimeters, particularly for the characterization of catalysts. This chapter gives a detailed overview of the uptodate thermal techniques covering various techniques including Differential Thermal Analysis (DTA), Differential Scanning Calorimetry (DSC), the calorimetric techniques (including Isothermal Calorimetry, Titration Calorimetry), Thermogravimetric Analysis (TGA), the combined techniques (including TG-DTA and TG-DSC), the Evolved Gas Analysis (including TG-MS, TG-FTIR). Some examples of applications are given to illustrate the catalyst characterizations.

  2. Liquid Argon Calorimetry with LHC-Performance Specifications

    CERN Multimedia

    2002-01-01

    % RD-3 Liquid Argon Calorimetry with LHC-Performance Specifications \\\\ \\\\Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. Among the techniques used so far, or under development, the liquid argon sampling calorimetry offers high radiation resistence, good energy resolution (electromagnetic and hadronic), excellent calibration stability and response uniformity. Its rate capabilities, however, do not yet match the requirements for LHC. \\\\ \\\\The aim of this proposal is to improve the technique in such a way that high granularity, good hermiticity and adequate rate capabilities are obtained, without compromising the above mentioned properties. To reach this goal, we propose to use a novel structure, the $^{\\prime\\prime}$accordion$^{\\prime\\prime}$, coupled to fast preamplifiers working at liquid argon temperature. Converter and readout electrodes are no longer planar and perpendicular to particles, as usual, but instead they are wiggled around a plane containing particles. ...

  3. Particle flow calorimetry at the international linear collider

    Indian Academy of Sciences (India)

    jet energy resolution. It is widely believed that the particle flow approach to calorimetry is the key to achieving the goal of 0.3/. √. E(GeV). This paper describes the current performance of the PandoraPFA particle flow algorithm. For 45GeV jets in the Tesla. TDR detector concept, the ILC jet energy resolution goal is reached.

  4. A study of ultra-strength polymer fibers via calorimetry

    Science.gov (United States)

    Egorov, V. M.; Boiko, Yu. M.; Marikhin, V. A.; Myasnikova, L. P.; Radovanova, E. I.

    2016-08-01

    Xerogel reactor powders and supramolecular polyethylene fibers with various degrees of hood have been studied via differential scanning calorimetry. A higher strength of laboratory fibers in comparison with industrial ones is found to be achieved due to a multistage band high-temperature hood that causes the thermodynamic parameters of supramolecular polymer structure.

  5. Particle flow calorimetry at the international linear collider

    Indian Academy of Sciences (India)

    2015-11-27

    Nov 27, 2015 ... One of the most important requirements for a detector at the ILC is good jet energy resolution. It is widely believed that the particle flow approach to calorimetry is the key to achieving the goal of 0.3 / E ( G e V ) . This paper describes the current performance of the PandoraPFA particle flow algorithm. For 45 ...

  6. Indirect calorimetry: assessing animal response to heat and cold stress

    NARCIS (Netherlands)

    Gaughan, J.B.; Heetkamp, M.J.W.; Hendriks, P.

    2015-01-01

    Calorimetric thermal stress studies where indirect calorimetry is used as a tool to estimate energy expenditure have been undertaken since this technique was developed. Some examples of these studies are presented in this chapter. The measurement of gas exchange by means of an open-circuit

  7. Isothermal Titration Calorimetry Can Provide Critical Thinking Opportunities

    Science.gov (United States)

    Moore, Dale E.; Goode, David R.; Seney, Caryn S.; Boatwright, Jennifer M.

    2016-01-01

    College chemistry faculties might not have considered including isothermal titration calorimetry (ITC) in their majors' curriculum because experimental data from this instrumental method are often analyzed via automation (software). However, the software-based data analysis can be replaced with a spreadsheet-based analysis that is readily…

  8. The Simulation of the ATLAS Liquid Argon Calorimetry

    CERN Document Server

    Archambault, J P; Carli, T; Costanzo, D; Dell'Acqua, A; Djama, F; Gallas, M; Fincke-Keeler, M; Khakzad, M; Kiryunin, A; Krieger, P; Leltchouk, M; Loch, P; Ma, H; Menke, S; Monnier, E; Nairz, A; Niess, V; Oakham, G; Oram, C; Pospelov, G; Rajagopalan, S; Rimoldi, A; Rousseau, D; Rutherfoord, J; Seligman, W; Soukharev, A; Strízenec, P; Tóth, J; Tsukerman, I; Tsulaia, V; Unal, G; Grahn, K J

    2008-01-01

    In ATLAS, all of the electromagnetic calorimetry and part of the hadronic calorimetry is performed by a calorimeter system using liquid argon as the active material, together with various types of absorbers. The liquid argon calorimeter consists of four subsystems: the electromagnetic barrel and endcap accordion calorimeters; the hadronic endcap calorimeters, and the forward calorimeters. A very accurate geometrical description of these calorimeters is used as input to the Geant 4-based ATLAS simulation, and a careful modelling of the signal development is applied in the generation of hits. Certain types of Monte Carlo truth information ("Calibration Hits") may, additionally, be recorded for calorimeter cells as well as for dead material. This note is a comprehensive reference describing the simulation of the four liquid argon calorimeteter components.

  9. Scintillating glasses for total absorption dual readout calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bonvicini, V. [INFN, Trieste; Driutti, A. [Udine U.; Cauz, D. [Udine U.; Pauletta, G. [Udine U.; Rubinov, P. [Fermilab; Santi, L. [Udine U.; Wenzel, H. [Fermilab

    2012-01-01

    Scintillating glasses are a potentially cheaper alternative to crystal - based calorimetry with common problems related to light collection, detection and processing. As such, their use and development are part of more extensive R&D aimed at investigating the potential of total absorption, combined with the readout (DR) technique, for hadron calorimetry. A recent series of measurements, using cosmic and particle beams from the Fermilab test beam facility and scintillating glass with the characteristics required for application of the DR technique, serve to illustrate the problems addressed and the progress achieved by this R&D. Alternative solutions for light collection (conventional and silicon photomultipliers) and signal processing are compared, the separate contributions of scintillation and Cherenkov processes to the signal are evaluated and results are compared to simulation.

  10. Thermal Properties of Trogamid by Conventional and Fast Scanning Calorimetry

    Science.gov (United States)

    Cebe, Peggy; Merfeld, John; Mao, Bin; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    We use conventional slow scan rate differential scanning calorimetry, and fast scanning chip-based calorimetry (FSC), to investigate the crystallization and melting behavior of Trogamid, a chemical relative of nylon. Fundamental thermal properties of Trogamid were studied, including the melt crystallization kinetics, heat of fusion, and the solid and liquid state heat capacities. Using slow scan DSC (at 5 K/min), Trogamid displays a glass transition relaxation process at ~133 C, melting endotherm peak at 250 C, and is stable upon repeated heating to 310 C. When using slow scan DSC, the isothermal melt crystallization temperatures were restricted to 225 C or above. Trogamid crystallizes rapidly from the melt and conventional calorimetry is unable to cool sufficiently fast to prevent nucleation and crystal growth prior to stabilization at lower crystallization temperatures. Using FSC we were able to cool nano-gram sizes samples at 2000 K/s to investigate a much lower range of melt crystallization temperatures, from 205-225 C. The experimental protocol for performing FSC on semicrystalline polymers to obtain liquid state heat capacity data will be presented. National Science Foundation, Polymers Program DMR-1206010; DAAD; Tufts Faculty Supported Leave.

  11. Isothermal Titration Calorimetry: Assisted Crystallization of RNA-Ligand Complexes.

    Science.gov (United States)

    Da Veiga, Cyrielle; Mezher, Joelle; Dumas, Philippe; Ennifar, Eric

    2016-01-01

    The success rate of nucleic acids/ligands co-crystallization can be significantly improved by performing preliminary biophysical analyses. Among suitable biophysical approaches, isothermal titration calorimetry (ITC) is certainly a method of choice. ITC can be used in a wide range of experimental conditions to monitor in real time the formation of the RNA- or DNA-ligand complex, with the advantage of providing in addition the complete binding profile of the interaction. Following the ITC experiment, the complex is ready to be concentrated for crystallization trials. This chapter describes a detailed experimental protocol for using ITC as a tool for monitoring RNA/small molecule binding, followed by co-crystallization.

  12. Isothermal titration calorimetry for studying protein-ligand interactions.

    Science.gov (United States)

    Damian, Luminita

    2013-01-01

    Isothermal titration calorimetry (ITC) is a biophysical technique that allows a thermodynamic characterization of an interactive system. It is a free in solution technique that requires no labeling, using heat as signal. ITC allows simultaneous determination of affinity K a, stoichiometry n, enthalpy change ΔH and calculation of free energy change ΔG and entropy change ΔS in one single experiment. It is the only technique that allows direct enthalpy change measurement. By accessing the enthalpy change, we get a step closer in estimating the driving forces that characterize the interaction of a protein with a ligand, information much needed in the drug discovery process.

  13. Applications of isothermal titration calorimetry in RNA biochemistry and biophysics.

    Science.gov (United States)

    Feig, Andrew L

    Isothermal titration calorimetry (ITC) has been applied to the study of proteins for many years. Its use in the biophysical analysis of RNAs has lagged significantly behind its use in protein biochemistry, however, in part because of the relatively large samples required. As the instrumentation has become more sensitive, the ability to obtain high quality data on RNA folding and RNA ligand interactions has improved dramatically. This review provides an overview of the ITC experiment and describes recent work on RNA systems that have taken advantage of its versatility for the study of small molecule binding, protein binding, and the analysis of RNA folding. (c) 2007 Wiley Periodicals, Inc.

  14. Mechanics from Calorimetry: Probing the Elasticity of Responsive Hydrogels

    Science.gov (United States)

    Aangenendt, Frank J.; Mattsson, Johan; Ellenbroek, Wouter G.; Wyss, Hans M.

    2017-07-01

    Temperature-sensitive hydrogels based on polymers such as poly(N -isopropylacrylamide) (PNIPAM) undergo a volume phase transition in response to changes in temperature. During this transition, distinct changes in both thermal and mechanical properties are observed. Here, we illustrate and exploit the inherent thermodynamic link between thermal and mechanical properties by showing that the compressive elastic modulus of PNIPAM hydrogels can be probed using differential scanning calorimetry. We validate our approach by using conventional osmotic compression tests. Our method could be particularly valuable for determining the mechanical response of thermosensitive submicron-sized and/or oddly shaped particles, to which standard methods are not readily applicable.

  15. Fast differential scanning calorimetry of liquid samples with chips

    DEFF Research Database (Denmark)

    Splinter, R.; van Herwaarden, A. W.; van Wetten, I. A.

    2015-01-01

    Based on a modified version of standard chips for fast differential scanning calorimetry, DSC of liquid samples has been performed at temperature scan rates of up to 1000 °C/s. This paper describes experimental results with the protein lysozyme, bovine serum, and olive oil. The heating and cooling....... The bovine serum measurements show two main peaks, in good agreement with standard DSC measurements. Olive oil has been measured, with good agreement for the cooling curve and qualitative agreement for the heater curve, compared to DSC measurements....

  16. Detectors for Linear Colliders: Calorimetry at a Future Electron-Positron Collider (3/4)

    CERN Multimedia

    CERN. Geneva

    2010-01-01

    Calorimetry will play a central role in determining the physics reach at a future e+e- collider. The requirements for calorimetry place the emphasis on achieving an excellent jet energy resolution. The currently favoured option for calorimetry at a future e+e- collider is the concept of high granularity particle flow calorimetry. Here granularity and a high pattern recognition capability is more important than the single particle calorimetric response. In this lecture I will describe the recent progress in understanding the reach of high granularity particle flow calorimetry and the related R&D efforts which concentrate on test beam demonstrations of the technological options for highly granular calorimeters. I will also discuss alternatives to particle flow, for example the technique of dual readout calorimetry.

  17. Application of an open circuit indirect calorimetry system for gaseous exchange measurements in small ruminant nutrition

    OpenAIRE

    CRISCIONI FERREIRA, PATRICIA FABIOLA

    2016-01-01

    [EN] The main objective of this Thesis was to study the energy metabolism in small ruminants under different nutrition sceneries. As methodology we utilized indirect calorimetry instead of direct calorimetry or feeding trials. Within indirect calorimetry we worked with a portable open circuit gas exchange system with a head hood. This open circuit respiration system permitted completed the whole energy balance and evaluate the efficiency of utilization of the energy of the diet for different ...

  18. Characterizing Optical Loss in Orientation Patterned III-V Materials using Laser Calorimetry

    Science.gov (United States)

    2014-03-27

    32 Figure 15: Sample mount used for calorimetry experiment.. .......................................... 34 Figure 16: Styrofoam box enclosure...Page Figure 17: Proof of thermal insulation provided by the Styrofoam box...

  19. Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

    DEFF Research Database (Denmark)

    Søtoft, Lene Fjerbaek; Westh, Peter; Christensen, Knud V.

    2010-01-01

    Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 °C. The aim of the study was to determine reaction enthalpy for the enzymatic...... transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 °C for the two systems was determined as −9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and −9.3 ± 0.7 k...

  20. Review of MEMS differential scanning calorimetry for biomolecular study

    Science.gov (United States)

    Yu, Shifeng; Wang, Shuyu; Lu, Ming; Zuo, Lei

    2017-12-01

    Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermodynamics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightforward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs.

  1. Fragment-Based Screening for Enzyme Inhibitors Using Calorimetry.

    Science.gov (United States)

    Recht, Michael I; Nienaber, Vicki; Torres, Francisco E

    2016-01-01

    Isothermal titration calorimetry (ITC) provides a sensitive and accurate means by which to study the thermodynamics of binding reactions. In addition, it enables label-free measurement of enzymatic reactions. The advent of extremely sensitive microcalorimeters have made it increasingly valuable as a tool for hit validation and characterization, but its use in primary screening is hampered by requiring large quantities of reagents and long measurement times. Nanocalorimeters can overcome these limitations of conventional ITC, particularly for screening libraries of 500-1000 compounds such as those encountered in fragment-based lead discovery. This chapter describes how nanocalorimetry and conventional microcalorimetry can be used to screen compound libraries for enzyme inhibitors. © 2016 Elsevier Inc. All rights reserved.

  2. Review of MEMS differential scanning calorimetry for biomolecular study

    Science.gov (United States)

    Yu, Shifeng; Wang, Shuyu; Lu, Ming; Zuo, Lei

    2017-07-01

    Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermodynamics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightforward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs.

  3. Characterization of protein-protein interactions by isothermal titration calorimetry.

    Science.gov (United States)

    Velazquez-Campoy, Adrian; Leavitt, Stephanie A; Freire, Ernesto

    2004-01-01

    Isothermal titration calorimetry (ITC) is a powerful technique to study both protein-ligand and protein-protein interactions. This methods chapter is devoted to describing protein-protein interactions, in particular, the association between two different proteins and the self-association of a protein into homodimers. ITC is the only technique that determines directly the thermodynamic parameters of a given reaction: DeltaG, DeltaH, DeltaS, and DeltaCP. Isothermal titration calorimeters have evolved over the years and one of the latest models is the VP-ITC produced by Microcal, Inc. In this chapter we will be describing the general procedure for performing an ITC experiment as well as for the specific cases of porcine pancreatic trypsin binding to soybean trypsin inhibitor and the dissociation of bovine pancreatic alpha-chymotrypsin.

  4. Isothermal titration calorimetry for measuring macromolecule-ligand affinity.

    Science.gov (United States)

    Duff, Michael R; Grubbs, Jordan; Howell, Elizabeth E

    2011-09-07

    Isothermal titration calorimetry (ITC) is a useful tool for understanding the complete thermodynamic picture of a binding reaction. In biological sciences, macromolecular interactions are essential in understanding the machinery of the cell. Experimental conditions, such as buffer and temperature, can be tailored to the particular binding system being studied. However, careful planning is needed since certain ligand and macromolecule concentration ranges are necessary to obtain useful data. Concentrations of the macromolecule and ligand need to be accurately determined for reliable results. Care also needs to be taken when preparing the samples as impurities can significantly affect the experiment. When ITC experiments, along with controls, are performed properly, useful binding information, such as the stoichiometry, affinity and enthalpy, are obtained. By running additional experiments under different buffer or temperature conditions, more detailed information can be obtained about the system. A protocol for the basic setup of an ITC experiment is given.

  5. Characterization of molecular interactions using isothermal titration calorimetry.

    Science.gov (United States)

    Krell, Tino; Lacal, Jesús; García-Fontana, Cristina; Silva-Jiménez, Hortencia; Rico-Jiménez, Miriam; Lugo, Andrés Corral; Darias, José Antonio Reyes; Ramos, Juan-Luis

    2014-01-01

    Isothermal titration calorimetry (ITC) is based on a simple titration of one ligand with another and the small heat changes caused by the molecular interaction are detected. From one ITC experiment the complete set of thermodynamic parameters of binding including association and dissociation constants as well as changes in enthalpy, entropy, and free energy can be derived. Using this technique almost any type of molecular interaction can be analyzed. Both ligands are in solution, and there is no need for their chemical derivatization. There are no limits as to the choice of the analysis buffer, and the analysis temperature can be set between 4 and 80 °C. This technique has been primarily applied to study the interaction between various proteins of Pseudomonas with small molecule ligands. In addition, ITC has been used to study the binding of Pseudomonas proteins to target DNA fragments.

  6. Do PICU patients meet technical criteria for performing indirect calorimetry?

    Science.gov (United States)

    Beggs, Megan R; Garcia Guerra, Gonzalo; Larsen, Bodil M K

    2016-10-01

    Indirect calorimetry (IC) is considered gold standard for assessing energy needs of critically ill children as predictive equations and clinical status indicators are often unreliable. Accurate assessment of energy requirements in this vulnerable population is essential given the high risk of over or underfeeding and the consequences thereof. The proportion of patients and patient days in pediatric intensive care (PICU) for which energy expenditure (EE) can be measured using IC is currently unknown. In the current study, we aimed to quantify the daily proportion of consecutive PICU patients who met technical criteria to perform indirect calorimetry and describe the technical contraindications when criteria were not met. Prospective, observational, single-centre study conducted in a cardiac and general PICU. All consecutive patients admitted for at least 96 h were included in the study. Variables collected for each patient included age at admission, admission diagnosis, and if technical criteria for indirect calorimetry were met. Technical criteria variables were collected within the same 2 h each morning and include: provision of supplemental oxygen, ventilator settings, endotracheal tube (ETT) leak, diagnosis of chest tube air leak, provision of external gas support (i.e. nitric oxide), and provision of extracorporeal membrane oxygenation (ECMO). 288 patients were included for a total of 3590 patient days between June 2014 and February 2015. The main reasons for admission were: surgery (cardiac and non-cardiac), respiratory distress, trauma, oncology and medicine/other. The median (interquartile range) patient age was 0.7 (0.3-4.6) years. The median length of PICU stay was 7 (5-14) days. Only 34% (95% CI, 32.4-35.5%) of patient days met technical criteria for IC. For patients less than 6 months of age, technical criteria were met on significantly fewer patient days (29%, p meet technical criteria for IC on any day during their PICU stay. Most frequent reasons

  7. The importance of calorimetry for highly-boosted jet substructure

    Energy Technology Data Exchange (ETDEWEB)

    Coleman, Evan [Brown U.; Freytsis, Marat [Oregon U.; Hinzmann, Andreas [Hamburg U.; Narain, Meenakshi [Brown U.; Thaler, Jesse [MIT, Cambridge, CTP; Tran, Nhan [Fermilab; Vernieri, Caterina [Fermilab

    2017-09-25

    Jet substructure techniques are playing an essential role in exploring the TeV scale at the Large Hadron Collider (LHC), since they facilitate the efficient reconstruction and identification of highly-boosted objects. Both for the LHC and for future colliders, there is a growing interest in using jet substructure methods based only on charged-particle information. The reason is that silicon-based tracking detectors offer excellent granularity and precise vertexing, which can improve the angular resolution on highly-collimated jets and mitigate the impact of pileup. In this paper, we assess how much jet substructure performance degrades by using track-only information, and we demonstrate physics contexts in which calorimetry is most beneficial. Specifically, we consider five different hadronic final states - W bosons, Z bosons, top quarks, light quarks, gluons - and test the pairwise discrimination power with a multi-variate combination of substructure observables. In the idealized case of perfect reconstruction, we quantify the loss in discrimination performance when using just charged particles compared to using all detected particles. We also consider the intermediate case of using charged particles plus photons, which provides valuable information about neutral pions. In the more realistic case of a segmented calorimeter, we assess the potential performance gains from improving calorimeter granularity and resolution, comparing a CMS-like detector to more ambitious future detector concepts. Broadly speaking, we find large performance gains from neutral-particle information and from improved calorimetry in cases where jet mass resolution drives the discrimination power, whereas the gains are more modest if an absolute mass scale calibration is not required.

  8. The importance of calorimetry for highly-boosted jet substructure

    Science.gov (United States)

    Coleman, E.; Freytsis, M.; Hinzmann, A.; Narain, M.; Thaler, J.; Tran, N.; Vernieri, C.

    2018-01-01

    Jet substructure techniques are playing an essential role in exploring the TeV scale at the Large Hadron Collider (LHC), since they facilitate the efficient reconstruction and identification of highly-boosted objects. Both for the LHC and for future colliders, there is a growing interest in using jet substructure methods based only on charged-particle information. The reason is that silicon-based tracking detectors offer excellent granularity and precise vertexing, which can improve the angular resolution on highly-collimated jets and mitigate the impact of pileup. In this paper, we assess how much jet substructure performance degrades by using track-only information, and we demonstrate physics contexts in which calorimetry is most beneficial. Specifically, we consider five different hadronic final states—W bosons, Z bosons, top quarks, light quarks, gluons—and test the pairwise discrimination power with a multi-variate combination of substructure observables. In the idealized case of perfect reconstruction, we quantify the loss in discrimination performance when using just charged particles compared to using all detected particles. We also consider the intermediate case of using charged particles plus photons, which provides valuable information about neutral pions. In the more realistic case of a segmented calorimeter, we assess the potential performance gains from improving calorimeter granularity and resolution, comparing a CMS-like detector to more ambitious future detector concepts. Broadly speaking, we find large performance gains from neutral-particle information and from improved calorimetry in cases where jet mass resolution drives the discrimination power, whereas the gains are more modest if an absolute mass scale calibration is not required.

  9. Front-End Electronics in calorimetry: from LHC to ILC

    Energy Technology Data Exchange (ETDEWEB)

    De La Taille, Ch.

    2009-09-15

    This report summarizes the electronics developments for liquid argon calorimeter read-out at LHC and the development carried out in the framework of the CALICE collaboration for those of the future linear collider (ILC). It also includes chips designed for multi-anode photomultipliers (MaPMT) used in the OPERA experiment or on ATLAS luminometer, which also find applications in medical imaging. Started in the early 90's, the development for ATLAS calorimetry was extremely challenging in terms of readout speed, radiation tolerance and measurement accuracy. The high speed has required a new approach using current-sensitive preamplifiers instead of charge sensitive ones and the redefinition of noise performance in terms of ENI. The preamplifiers developed at Orsay and the monolithic shapers are described in Chapter 1, including considerations of digital filtering, which was a new technique in our field. Chapter 2 is dedicated to the calibration system, designed and built by Orsay, for which the high performance and accuracy necessitated in-depth studies. The 3. chapter closes the studies for ATLAS with a summary of the detector measurements which had to be carried out on the 200 000 channels in order to understand and model the detector and achieve everywhere the accuracy and uniformity at per-cent level. These developments for ATLAS ended in 2004, although parallel work was also carried out for the NA48 and DO calorimeters which are not detailed here. The next generation of collider will require a new generation of calorimeters, much more granular, referred to as 'imaging calorimetry' with embedded read-out electronics. The ASICs developed for this purpose in the framework of the CALICE collaboration are described in Chapter 4. They integrate all the functionalities of amplification, digitization and read-out making them complex 'System-On-Chip' circuits extremely efficient that find many other applications. A family of 3 chips reads out the

  10. Survey of the year 2008: applications of isothermal titration calorimetry.

    Science.gov (United States)

    Falconer, Robert J; Penkova, Anita; Jelesarov, Ilian; Collins, Brett M

    2010-01-01

    Isothermal titration calorimetry (ITC) is a fast, accurate and label-free method for measuring the thermodynamics and binding affinities of molecular associations in solution. Because the method will measure any reaction that results in a heat change, it is applicable to many different fields of research from biomolecular science, to drug design and materials engineering, and can be used to measure binding events between essentially any type of biological or chemical ligand. ITC is the only method that can directly measure binding energetics including Gibbs free energy, enthalpy, entropy and heat capacity changes. Not only binding thermodynamics but also catalytic reactions, conformational rearrangements, changes in protonation and molecular dissociations can be readily quantified by performing only a small number of ITC experiments. In this review, we highlight some of the particularly interesting reports from 2008 employing ITC, with a particular focus on protein interactions with other proteins, nucleic acids, lipids and drugs. As is tradition in these reviews we have not attempted a comprehensive analysis of all 500 papers using ITC, but emphasize those reports that particularly captured our interest and that included more thorough discussions we consider exemplify the power of the technique and might serve to inspire other users.

  11. Novel investigation of enzymatic biodiesel reaction by isothermal calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sotoft, Lene Fjerbaek, E-mail: lfj@kbm.sdu.dk [Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Westh, Peter [Department of Life Science and Chemistry, Roskilde University, PO Box 260, DK-4000 Roskilde (Denmark); Christensen, Knud V.; Norddahl, Birgir [Institute of Chemical Engineering, Biotechnology and Environmental Technology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

    2010-03-30

    Isothermal calorimetry (ITC) was used to investigate solvent-free enzymatic biodiesel production. The transesterification of rapeseed oil with methanol and ethanol was catalyzed by immobilized lipase Novozym 435 at 40 {sup o}C. The aim of the study was to determine reaction enthalpy for the enzymatic transesterification and to elucidate the mass transfer and energetic processes taking place. Based on the measured enthalpy and composition change in the system, the heat of reaction at 40 {sup o}C for the two systems was determined as -9.8 {+-} 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and -9.3 {+-} 0.7 kJ/mole when rapeseed oil and ethanol was used. Simple Michaelis-Menten kinetics was not an appropriate choice for describing the kinetics of this heterogeneous system. The experiments demonstrated the possibility of investigating complex reaction mixtures using ITC. Although it is possible to determine thermodynamic properties such as reaction enthalpy and reaction rate, the difficulty in actually measuring the true non-mass-transfer-limited reaction kinetics is exposed by the high time resolution of ITC.

  12. Study of Liquid Argon Dopants for LHC Hadron Calorimetry

    CERN Multimedia

    2002-01-01

    Hadron calorimetry based on the Liquid Argon Ionisation Chamber technique is one of the choice techniques for LHC-experimentation. A systematic study of the effect of selected dopants on Liquid Argon (LAr) will be carried out with the aim to achieve an improvement on: \\item (i)~``Fast Liquid Argon'' search and study of dopants to increase the drift velocity. It has been already shown that CH&sub4. added at a fraction of one percent increases the drift velocity by a factor of two or more. \\item (ii)~``Compensated Liquid Argon'' search and study of dopants to increase the response to densely ionising particles, resulting in improved compensation, such as photosensitive dopants. \\end{enumerate}\\\\ \\\\ Monitoring of the parameters involved in understanding the response of a calorimeter is essential. In case of doped LAr, the charge yield, the non-saturated drift velocity and the electron lifetime in the liquid should be precisely and simultaneously monitored as they all vary with the level of dopant concentrati...

  13. High-pressure differential scanning calorimetry of colorant products.

    Science.gov (United States)

    Marsh, J M; Clarke, C J; Meinert, K; Dahlgren, R M

    2007-01-01

    High-pressure differential scanning calorimetry (HPDSC) can be used to gain information on both the degree of crystallinity in the intermediate filaments (IFs) and the structural rigidity of the surrounding matrix or intermediate filament associated proteins (IFAP) of the hair cortex (1-3). We have used HPDSC to measure changes in the denaturation temperature (T(D)) and enthalpy (DeltaH(D)) of the crystalline components after multiple treatments with permanent hair colorant products. We have observed that after three repeat treatments both the denaturation enthalpy and peak temperature are significantly decreased vs the untreated starting substrate. However, on dialysis of the fibers in deionized water this decrease is shown to be completely reversible, returning the enthalpy and temperature to that of the untreated hair. It is proposed that the decrease is due to the incorporation of formulation components such as the alkalizer and surfactants etc. and metal ions such as calcium and magnesium from the tap wash water. These components are predicted to have a non-permanent effect on the salt bridges and hydrogen bonds and hence the rigidity or viscosity of the matrix. We have compared the denaturation temperature with the tensile properties of the fiber after treatment both before and after removal of actives from the fiber.

  14. Measuring the Kinetics of Molecular Association by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Vander Meulen, Kirk A; Horowitz, Scott; Trievel, Raymond C; Butcher, Samuel E

    2016-01-01

    The real-time power response inherent in an isothermal titration calorimetry (ITC) experiment provides an opportunity to directly analyze association kinetics, which, together with the conventional measurement of thermodynamic quantities, can provide an incredibly rich description of molecular binding in a single experiment. Here, we detail our application of this method, in which interactions occurring with relaxation times ranging from slightly below the instrument response time constant (12.5 s in this case) to as large as 600 s can be fully detailed in terms of both the thermodynamics and kinetics. In a binding titration scenario, in the most general case an injection can reveal an association rate constant (kon). Under more restrictive conditions, the instrument time constant-corrected power decay following each injection is simply an exponential decay described by a composite rate constant (kobs), from which both kon and the dissociation rate constant (koff) can be extracted. The data also support the viability of this exponential approach, for kon only, for a slightly larger set of conditions. Using a bimolecular RNA folding model and a protein-ligand interaction, we demonstrate and have internally validated this approach to experiment design, data processing, and error analysis. An updated guide to thermodynamic and kinetic regimes accessible by ITC is provided. © 2016 Elsevier Inc. All rights reserved.

  15. Applying fast calorimetry on a spent nuclear fuel calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Liljenfeldt, Henrik [Swedish Nuclear Fuel and Waste Management (Sweden); Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Uppsala Univ. (Sweden)

    2015-04-15

    Recently at Los Alamos National Laboratory, sophisticated prediction algorithms have been considered for the use of calorimetry for treaty verification. These algorithms aim to predict the equilibrium temperature based on early data and therefore be able to shorten the measurement time while maintaining good accuracy. The algorithms have been implemented in MATLAB and applied on existing equilibrium measurements from a spent nuclear fuel calorimeter located at the Swedish nuclear fuel interim storage facility. The results show significant improvements in measurement time in the order of 15 to 50 compared to equilibrium measurements, but cannot predict the heat accurately in less time than the currently used temperature increase method can. This Is both due to uncertainties in the calibration of the method as well as identified design features of the calorimeter that limits the usefulness of equilibrium type measurements. The conclusions of these findings are discussed, and suggestions of both improvements of the current calorimeter as well as what to keep in mind in a new design are given.

  16. Thermal Properties of Silk Fibroin Using Fast Scanning Calorimetry

    Science.gov (United States)

    Cebe, Peggy; Partlow, Benjamin; Kaplan, David; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    We performed fast scanning chip-based calorimetry of silk protein using the Mettler Flash DSC1. We suggest the methodology by which to obtain quantitative information on the very first scan to high temperature, including the melting endotherm of the beta pleated sheets. For proteins, this first scan is the most important one, because the crystalline secondary structural features, the beta pleated sheets, melt after the first heating and cannot be thermally reintroduced. To obtain high quality data, the samples must be treated to drying and enthalpy relaxation sequences. The heat flow rates in heating and cooling must be corrected for asymmetric heat loses. We evaluate methods to obtain an estimate of the sample mass, finally choosing internal calibration using the known heat capacity increment at the glass transition. We report that even heating at rates of 2000 K/s, thermal degradation of silk cannot be totally avoided, though it can be minimized. Using a set of nineteen samples, we successfully determine the liquid state heat capacity of silk as: Cpliquid (T) = (1.98 +0.06) J/gK + T (6.82 +1.4) x10-4 J/gK2. Methods for estimation of the sample mass will be presented and compared. National Science Foundation, Polymers Program DMR-1206010; DAAD; Tufts Faculty Supported Leave.

  17. PREFACE: XIV International Conference on Calorimetry in High Energy Physics

    Science.gov (United States)

    Wang, Yifang

    2011-03-01

    The International Conferences on Calorimetry in High Energy Physics (also known as the Calor Conference series, started in October 1990 at Fermilab) address all aspects of calorimetric particle detection and measurement, with an emphasis on high energy physics experiments. The XIV International Conference on Calorimetry in High Energy Physics (Calor 2010) was held at the campus of the Institute of High Energy Physics, Beijing, China, from May 10-14, 2010. This conference brought together more than 110 participants from 20 countries, including senior scientists and young physicists. During the five days of the conference, 98 presentations were given in seven plenary sessions. The attendees had in-depth discussions on the latest developments and innovations in calorimetry, including the exciting new LHC results. From the presentations, 83 papers were published in this proceedings. The success of the conference was due to the participants' enthusiasm and the excellent talks given by the speakers, and to the conveners for organizing the individual sessions. We would like to thank the International Advisory Committee for giving us the opportunity to host this Conference in Beijing. Finally we would like to thank all the people involved in the organization of the Conference, who have provided valuable local support. Yifang WangChair of Local Organizing Committee International Advisory Committee M DanilovITEP Moscow M DiemozINFN Roma I A EreditatoBern F L FabbriINFN Frascati T KobayashiICEPP Tokyo M LivanPavia University & INFN P LubranoINFN Perugia S MagillANL Argonne A MaioLIPP Lisbon H OberlackMPI Munich A ParaFermilab R WigmansTTU Lubbock R YoshidaANL Argonne R ZhuCaltech Local Organizing Committee Y WangIHEP (Chair) Y GaoTshinghua University T HuIHEP (Scientific secretary) C LiUSTC W LiIHEP J LuIHEP P WangIHEP T XuIHEP L ZhouIHEP Session Conveners 1) Materials and detectors - Junguang Lu (IHEP), Francesca Nessi (CERN) 2) Algorithm and simulation - Nural Akchurin

  18. Silk I and Silk II studied by fast scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cebe, Peggy; Partlow, Benjamin P.; Kaplan, David L.; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph

    2017-06-01

    Using fast scanning calorimetry (FSC), we investigated the glass transition and crystal melting of samples of B. mori silk fibroin containing Silk I and/or Silk II crystals. Due to the very short residence times at high temperatures during such measurements, thermal decomposition of silk protein can be significantly suppressed. FSC was performed at 2000 K/s using the Mettler Flash DSC1 on fibroin films with masses around 130–270 ng. Films were prepared with different crystalline fractions (ranging from 0.26 to 0.50) and with different crystal structures (Silk I, Silk II, or mixed) by varying the processing conditions. These included water annealing at different temperatures, exposure to 50% MeOH in water, or autoclaving. The resulting crystal structure was examined using wide angle X-ray scattering. Degree of crystallinity was evaluated from Fourier transform infrared (FTIR) spectroscopy and from analysis of the heat capacity increment at the glass transition temperature. Silk fibroin films prepared by water annealing at 25 °C were the least crystalline and had Silk I structure. FTIR and FSC studies showed that films prepared by autoclaving or 50% MeOH exposure were the most crystalline and had Silk II structure. Intermediate crystalline fraction and mixed Silk I/Silk II structures were found in films prepared by water annealing at 37 °C. FSC results indicate that Silk II crystals exhibit endotherms of narrower width and have higher mean melting temperature Tm(II) = 351 ± 2.6 °C, compared to Silk I crystals which melt at Tm(I) = 292 ± 3.8 °C. Films containing mixed Silk I/Silk II structure showed two clearly separated endothermic peaks. Evidence suggests that the two types of crystals melt separately and do not thermally interconvert on the extremely short time scale (0.065 s between onset and end of melting) of the FSC experiment.

  19. Characterization of β-lactamase activity using isothermal titration calorimetry.

    Science.gov (United States)

    Wang, Wen-Jing; Wang, Qian; Zhang, Ye; Lu, Rui; Zhang, Yi-Lin; Yang, Ke-Wu; Lei, Jin-E; He, Yuan

    2017-08-01

    Hydrolysis of β-lactam antibiotic by β-lactamase is the most common mechanism of β-lactam resistance in clinical isolates. Timely detection and characterization of β-lactamases are therefore of utmost biomedical importance. Conventional spectrophotometric method is time-consuming and cannot provide thermodynamic information on β-lactamases. A new assay was developed for the study of β-lactamase activity in protein solutions (Metallo-β-lactamase L1) and in clinical bacterial cells, based on heat-flow changes derived from enzymatic hydrolysis of β-lactams using isothermal titration calorimetry. (1) The thermokinetic parameters of three antibiotics (penicillin G, cefazolin and imipenem) and the inhibition constant of an azolylthioacetamide inhibitor were determined using the calorimetric assay. The results from the calorimetric assays were consistent with the data from the spectrophotometric assay. (2) The values of heat change in the calorimetric assay using two clinical Escherichia coli strains correlated well with their antibiotic susceptibility results from the broth dilution experiment. The subtypes of β-lactamase were also determined in the calorimetric assay. The ITC assay is a reliable and fast method to study β-lactamase enzyme kinetics and inhibition. It can also provide thermodynamic information on antibiotic hydrolysis, which has been taken advantage of in this work to study β-lactamase activity in two clinical Escherichia coli isolates. As the first calorimetric study of β-lactamase activity, it may provide a new assay to assist biomedical validation of new β-lactamase inhibitors, and also has potential applications on rapid antibiotic susceptibility testing and screening β-lactamase producing bacteria. Copyright © 2017. Published by Elsevier B.V.

  20. Calorimetry at the international linear collider. From simulation to reality

    Energy Technology Data Exchange (ETDEWEB)

    Wattimena, Nanda

    2010-02-15

    Calorimetry plays a crucial role in ongoing and upcoming high-energy physics experiments. To build a powerful calorimetric system with a performance tailored to the expected physics signatures, demands dedicated research and development of new readout technologies as well as dedicated reconstruction algorithms. The presented design of a calorimetric system which meets the high demands of precision physics at the future linear collider ILC, follows the paradigm of particle ow. Particle ow is a reconstruction principle that relies on a calorimetric system with high spatial granularity. In the detector optimisation process, the development of hardware and software are interlinked and cannot be judged independently. This thesis addresses two different aspects of detector optimisation, a test of the detector design against one example physics scenario and the development of a stable calibration procedure. In the rst part, a gauge-mediated Supersymmetry breaking scenario is used to test the design of the electromagnetic calorimeter in a full detector simulation study. The reconstruction of the neutralino properties, each decaying into a photon and a gravitino, requires a good energy resolution, as well as excellent position and angular resolution. The error bounds on the neutralino mass is strongly linked to the energy resolution, while the position and angular reconstruction of neutral particles is essential for the determination of the neutralino lifetime. The second part of this thesis focuses on the calibration procedure for a prototype of the hadron calorimeter. 7608 novel photodetectors are operated and tested in this prototype. They are exposed to beams of well de ned particle type and energy. The calibration is tested with a detailed study of electromagnetic showers inside the cubic-metre-sized prototype, with special attention paid towards the non-linearity correction. (orig.)

  1. Parallelism between gradient temperature raman spectroscopy and differential scanning calorimetry results

    Science.gov (United States)

    Temperature dependent Raman spectroscopy (TDR) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur just prior to phase transitions. Herein we apply TDR and D...

  2. A Study of Concept Mapping as an Instructional Intervention in an Undergraduate General Chemistry Calorimetry Laboratory

    Science.gov (United States)

    Stroud, Mary W.

    This investigation, rooted in both chemistry and education, considers outcomes occurring in a small-scale study in which concept mapping was used as an instructional intervention in an undergraduate calorimetry laboratory. A quasi-experimental, multiple-methods approach was employed since the research questions posed in this study warranted the use of both qualitative and quantitative perspectives and evaluations. For the intervention group of students, a convenience sample, post-lab concept maps, written discussions, quiz responses and learning surveys were characterized and evaluated. Archived quiz responses for non-intervention students were also analyzed for comparison. Students uniquely constructed individual concept maps containing incorrect, conceptually correct and "scientifically thin" calorimetry characterizations. Students more greatly emphasized mathematical relationships and equations utilized during the calorimetry experiment; the meaning of calorimetry concepts was demonstrated to a lesser extent.

  3. An Integrated-Circuit Temperature Sensor for Calorimetry and Differential Temperature Measurement.

    Science.gov (United States)

    Muyskens, Mark A.

    1997-01-01

    Describes the application of an integrated-circuit (IC) chip which provides an easy-to-use, inexpensive, rugged, computer-interfaceable temperature sensor for calorimetry and differential temperature measurement. Discusses its design and advantages. (JRH)

  4. Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime Using Controlled Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Don W. Miller; Andrew Kauffmann; Eric Kreidler; Dongxu Li; Hanying Liu; Daniel Mills; Thomas D. Radcliff; Joseph Talnagi

    2001-12-31

    A comprehensive description of the accomplishments of the DOE grant titled, ''Local Measurement of Fuel Energy Deposition and Heat Transfer Environment During Fuel Lifetime using Controlled Calorimetry''.

  5. Proposal for continuing studies on lead/scintillating fibres calorimetry (LFC)

    CERN Document Server

    Anzivino, Giuseppina; Bari, G; Basile, M; Bellagamba, L; Bencheikh, C; Boscherini, D; Bruni, G; Bruni, P; Buzuloiu, V; Cara Romeo, G; Chiarini, M; Cifarelli, Luisa; Cindolo, F; Ciralli, F; Contin, A; Dardo, M; De Pasquale, S; DeSalvo, R; Frasconi, F; Gheorghe, A; Giusti, P; Hao, E; Iacobucci, G; Laurenti, G; Lundin, M; Maccarrone, G D; Margotti, A; Massam, Thomas; Mondardini, M R; Nania, R; Peskov, Vladimir; Sartorelli, G; Scioni, M; Timellini, R; Wang, Y; Xu, C; You, K; Zichichi, Antonino; CERN. Geneva. Detector Research and Development Committee

    1991-01-01

    Starting from the results obtained in the framework of the LAA Project 2B, we propose a continuation of the R&D on lead/scintillating fibres calorimetry ("spaghetti calorimetry"), including further tests on the old calorimeter prototypes and the construction and testing of new prototypes. The main results we pursue concern the performances of a projective calorimeter built with new, cheaper techniques and the radiation hardness of the scintillating fibres; the optimization of a preshower detector system is also studied.

  6. INDIRECT CALORIMETRY IN THE ASSESSMENT OF THE ENERGY REQUIREMENT IN OVERWEIGHT AND OBESE WOMEN

    Directory of Open Access Journals (Sweden)

    Ewa Lange

    2013-12-01

    Full Text Available Individual total energy expenditure may be calculated as a sum of basal energy requirement and energy expenditure associated with physical activity. Measurement of basal energy requirement is not often conducted in dietetic practice, but may be applied using indirect calorimetry. The aim of the analysis was to present the possibilities of using the Fitmate PRO monitor in the assessment of resting metabolic rate and basal energy expenditure with a method of indirect calorimetry in a group of 91 overweight and obese women in various age. The mean results of the resting metabolic rate measured with method of indirect calorimetry using the Fitmate PRO monitor did not differ in the age groups of overweight and obese women. The results of the resting metabolic rate measured with method of indirect calorimetry using the Fitmate PRO monitor were correlated with body mass, height, fat mass, muscle mass and waist circumference. The Fitmate PRO monitor may be a valuable tool in everyday dietetic practice to assess the basal energy expenditure with method of indirect calorimetry in a group of overweight and obese women.

  7. Effect of Body Position on Energy Expenditure of Preterm Infants as Determined by Simultaneous Direct and Indirect Calorimetry.

    Science.gov (United States)

    Bell, Edward F; Johnson, Karen J; Dove, Edwin L

    2017-04-01

    Background  Indirect calorimetry is the standard method for estimating energy expenditure in clinical research. Few studies have evaluated indirect calorimetry in infants by comparing it with simultaneous direct calorimetry. Our purpose was (1) to compare the energy expenditure of preterm infants determined by these two methods, direct calorimetry and indirect calorimetry; and (2) to examine the effect of body position, supine or prone, on energy expenditure. Study Design  We measured energy expenditure by simultaneous direct (heat loss by gradient-layer calorimeter corrected for heat storage) and indirect calorimetry (whole-body oxygen consumption and carbon dioxide production) in 15 growing preterm infants during two consecutive interfeeding intervals, once in the supine position and once in the prone position. Results  The mean energy expenditure for all measurements in both positions did not differ significantly by the method used: 2.82 (standard deviation [SD] 0.42) kcal/kg/h by direct calorimetry and 2.78 (SD 0.48) kcal/kg/h by indirect calorimetry. The energy expenditure was significantly lower, by 10%, in the prone than in the supine position, whether examined by direct calorimetry (2.67 vs. 2.97 kcal/kg/h, p  position than in the supine position. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  8. Study of interactions between hyaluronan and cationic surfactants by means of calorimetry, turbidimetry, potentiometry and conductometry.

    Science.gov (United States)

    Krouská, J; Pekař, M; Klučáková, M; Šarac, B; Bešter-Rogač, M

    2017-02-10

    The thermodynamics of the micelle formation of the cationic surfactants tetradecyltrimethylammonium bromide (TTAB) and cetyltrimethylammonium bromide (CTAB) with and without the addition of hyaluronan of two molecular weights was studied in aqueous solution by titration calorimetry. Macroscopic phase separation, which was detected by calorimetry and also by conductometry, occurs when charges on the surfactant and hyaluronan are balanced. In contrast, turbidimetry and potentiometry showed hyaluronan-surfactant interactions at very low surfactant concentrations. The observed differences between systems prepared with CTAB and TTAB indicate that besides the electrostatic interactions, which probably predominate, hydrophobic effects also play a significant role in hyaluronan interactions with cationic surfactants. Copyright © 2016 Elsevier Ltd. All rights reserved.

  9. Multithermal titration calorimetry: a rapid method to determine binding heat capacities.

    Science.gov (United States)

    Chavelas, Eneas A; Zubillaga, Rafael A; Pulido, Nancy O; García-Hernández, Enrique

    2006-03-01

    Herein a new method that allows binding DeltaCp to be determined with a single experiment is presented. Multithermal titration calorimetry (MTC) is a simple extension of isothermal titration calorimetry (ITC) that explicitly takes into account the thermal dependences of DeltaH and the binding constant. Experimentally, this is accomplished by performing a single stepwise titration with ITC equipment, allowing temperature re-adjustments of the system at intermediate states of the titration process. Thus, from the resulting multitherm, DeltaCp can also be determined. The experimental feasibility of MTC was tested by using the well-characterized lysozyme-chitotriose complex as a model system.

  10. Thermodynamics of Surfactants, Block Copolymers and Their Mixtures in Water: The Role of the Isothermal Calorimetry

    Science.gov (United States)

    De Lisi, Rosario; Milioto, Stefania; Muratore, Nicola

    2009-01-01

    The thermodynamics of conventional surfactants, block copolymers and their mixtures in water was described to the light of the enthalpy function. The two methodologies, i.e. the van’t Hoff approach and the isothermal calorimetry, used to determine the enthalpy of micellization of pure surfactants and block copolymers were described. The van’t Hoff method was critically discussed. The aqueous copolymer+surfactant mixtures were analyzed by means of the isothermal titration calorimetry and the enthalpy of transfer of the copolymer from the water to the aqueous surfactant solutions. Thermodynamic models were presented to show the procedure to extract straightforward molecular insights from the bulk properties. PMID:19742173

  11. Differential scanning calorimetry studies of Se85Te15–xPbx (x = 4, 6 ...

    Indian Academy of Sciences (India)

    Unknown

    2000-06-14

    Jun 14, 2000 ... quenched in ice cold water. About 10–15 mg of the powder samples were taken and subjected to the differen- tial scanning calorimetry at different heating rates. The DSC equipment was calibrated prior to the mea- surement using high purity elements such as Pb, Sn and. In, with known melting enthalpies ...

  12. Examination of water phase transitions in Loblolly pine and cell wall components by differential scanning calorimetry

    Science.gov (United States)

    Samuel L. Zelinka; Michael J. Lambrecht; Samuel V. Glass; Alex C. Wiedenhoeft; Daniel J. Yelle

    2012-01-01

    This paper examines phase transformations of water in wood and isolated wood cell wall components using differential scanning calorimetry with the purpose of better understanding "Type II water" or "freezable bound water" that has been reported for cellulose and other hydrophilic polymers. Solid loblolly pine (Pinus taeda...

  13. Enantioselectivity Measurements of Copper(II) Amino Acid Complexes Using Isothermal Titration Calorimetry

    NARCIS (Netherlands)

    Bruin, de T.J.M.; Marcelis, A.T.M.; Zuilhof, H.; Sudhölter, E.J.R.

    2000-01-01

    Enantioselectivity experiments for the binding to chiral Cu(II) complexes have been performed for several -amino acids using isothermal titration calorimetry. To a system containing nonionic micelles, Cu(II) ions, and cholesteryl glutamate as chiral selector, either the D- or L-amino acid was

  14. Aqueous solutions of proline and NaCl studied by differential scanning calorimetry at subzero temperatures

    DEFF Research Database (Denmark)

    Rasmussen, Peter Have; Jørgensen, Bo; Nielsen, Jette

    1997-01-01

    The hydration properties of proline are studied by differential scanning calorimetry (DSC) in aqueous solutions during freezing to -60 degrees C and subsequent heating to +20 degrees C. The concentration of proline in the freeze concentrated solution was estimated to approximately 50 wt% (w...

  15. Interaction between Humic Acid and Lysozyme, Studied by Dynamic Light Scattering and Isothermal Titration Calorimetry

    NARCIS (Netherlands)

    Tan, Wen Feng; Koopal, Luuk K.; Norde, Willem

    2009-01-01

    Interactions of purified Aldrich humic acid (PAHA) with the protein lysozyme (LSZ) are studied with dynamic light scattering and isothermal titration calorimetry by mixing LSZ and PAHA at various mass ratios. In solution LSZ is positive and PAHA is negative at the investigated pH values. Up to

  16. Thermodynamic investigations of protein's behaviour with ionic liquids in aqueous medium studied by isothermal titration calorimetry.

    Science.gov (United States)

    Bharmoria, Pankaj; Kumar, Arvind

    2016-05-01

    While a number of reports appear on ionic liquids-proteins interactions, their thermodynamic behaviour using suitable technique like isothermal titration calorimetry is not systematically presented. Isothermal titration calorimetry (ITC) is a key technique which can directly measure the thermodynamic contribution of IL binding to protein, particularly the enthalpy, heat capacities and binding stoichiometry. Ionic liquids (ILs), owing to their unique and tunable physicochemical properties have been the central area of scientific research besides graphene in the last decade, and growing unabated. Their encounter with proteins in the biological system is inevitable considering their environmental discharge though most of them are recyclable for a number of cycles. In this article we will cover the thermodynamics of proteins upon interaction with ILs as osmolyte and surfactant. The up to date literature survey of IL-protein interactions using isothermal titration calorimetry will be discussed and parallel comparison with the results obtained for such studies with other techniques will be highlighted to demonstrate the accuracy of ITC technique. Net stability of proteins can be obtained from the difference in the free energy (ΔG) of the native (folded) and denatured (unfolded) state using the Gibbs-Helmholtz equation (ΔG=ΔH-TΔS). Isothermal titration calorimetry can directly measure the heat changes upon IL-protein interactions. Calculation of other thermodynamic parameters such as entropy, binding constant and free energy depends upon the proper fitting of the binding isotherms using various fitting models. Copyright © 2015 Elsevier B.V. All rights reserved.

  17. Detection of sunflower oil in extra virgin olive oil by fast differential scanning calorimetry

    NARCIS (Netherlands)

    Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Boerrigter-Eenling, R.; Ruth, van S.M.

    2015-01-01

    Extra virgin olive oil (EVOO) is an economically valuable product, due to its high quality and premium price. Therefore it is vulnerable for adulteration by means of the addition of cheaper vegetable oils. Differential scanning calorimetry (DSC) has been suggested as a fast technique for the

  18. Low-temperature transitions in cod and tuna determined by differential scanning calorimetry

    DEFF Research Database (Denmark)

    Jensen, Kristina Nedenskov; Jørgensen, Bo; Nielsen, Jette

    2003-01-01

    Differential scanning calorimetry measurements have revealed different thermal transitions in cod and tuna samples. Transition temperatures detected Lit -11degreesC, -15degreesC and -21degreesC were highly dependent on the annealing temperature. In tuna muscle an additional transition was observed...

  19. Advanced Dilatometry and Calorimetry for the Validation of Materials Mechanical and Transformation Models

    Science.gov (United States)

    Reich, Michael; Milkereit, Benjamin; Krawutschke, Matthias; Kalich, Jan; Schick, Christoph; Kessler, Olaf

    Dilatometry and calorimetry are in situ methods to detect changes microstructure during heating or cooling of materials. They have been used for the analysis design of a short time heat treatment of the martensitic, press hardening, automobile body steel 22MnB5. The use of these both complementary experimental methods allows a critical consideration of the established results.

  20. On the Frequency Correction in Temperature-Modulated Differential Scanning Calorimetry of Glass Transition

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.

    2012-01-01

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequency...

  1. Insights into glass transition and relaxation behavior using temperature-modulated differential scanning calorimetry

    DEFF Research Database (Denmark)

    Guo, Xiaoju; Mauro, J.C.; Allan, D.C.

    Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range of freque...

  2. Thermodynamic profiling of Peptide membrane interactions by isothermal titration calorimetry: a search for pores and micelles

    DEFF Research Database (Denmark)

    Henriksen, Jonas Rosager; Andresen, Thomas Lars

    2011-01-01

    in mixed peptide-lipid micelles. We have investigated the mode of action of the antimicrobial peptide mastoparan-X using isothermal titration calorimetry (ITC) and cryo-transmission electron microscopy (cryo-TEM). The results show that mastoparan-X induces a range of structural transitions of POPC/POPG (3...

  3. Isothermal Titration Calorimetry and Macromolecular Visualization for the Interaction of Lysozyme and Its Inhibitors

    Science.gov (United States)

    Wei, Chin-Chuan; Jensen, Drake; Boyle, Tiffany; O'Brien, Leah C.; De Meo, Cristina; Shabestary, Nahid; Eder, Douglas J.

    2015-01-01

    To provide a research-like experience to upper-division undergraduate students in a biochemistry teaching laboratory, isothermal titration calorimetry (ITC) is employed to determine the binding constants of lysozyme and its inhibitors, N-acetyl glucosamine trimer (NAG[subscript 3]) and monomer (NAG). The extremely weak binding of lysozyme/NAG is…

  4. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

    Science.gov (United States)

    Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic proc...

  5. Phase behavior of polymer-diluent systems characterized by temperature modulated differential scanning calorimetry

    NARCIS (Netherlands)

    van der Heijden, P.C.; Mulder, M.H.V.; Wessling, Matthias

    2001-01-01

    The thermodynamic phase behavior of a polymer–diluent system (atactic polystyrene–1-dodecanol) forms the fundamental basis of the description of thermally-induced demixing processes. In this paper, we demonstrate that temperature modulated differential scanning calorimetry (TMDSC) can accurately

  6. Chemical kinetics on thermal decompositions of cumene hydroperoxide in cumene studied by calorimetry: An overview

    Energy Technology Data Exchange (ETDEWEB)

    Duh, Yih-Shing, E-mail: yihshingduh@yahoo.com.tw [Department of Occupation Safety and Health, Jen-Teh Junior College of Medicine, Nursing and Management, Miaoli, 35664, Taiwan, ROC (China); Department of Safety, Health and Environmental Engineering, National United University, No. 1 Lien-Da, Miaoli, 36052, Taiwan, ROC (China)

    2016-08-10

    Highlights: • Chemical kinetics on thermal decompositions of CHP are conducted and summarized. • Kinetics agrees well between data from DSC and adiabatic calorimetry. • Ea is determined to be about 120 kJ mol{sup −1} by various calorimetry. • LogA (A in s{sup −1}) is determined to be about 11.8 by various calorimetry. - Abstract: Study on chemical kinetics related to the thermal decomposition of cumene hydoperoxide (CHP) in cumene is summarized in this work. It is of great importance to gather and compare the differences between these kinetic parameters for further substantial applications in the chemical industry and process safety. CHP has been verified to possess an autocatalytic behavior by using microcalorimetry (such as TAM and C-80) operated at isothermal mode in the temperature range from 70 °C to 120 °C. However, it exhibits a reaction of n-th order detected by non-isothermal DSC scanning and adiabatic calorimeter. By the isothermal aging tests, activation energy and frequency factor in logA(s{sup −1}) were averaged to be (117.3 ± 5.9) kJ mol{sup −1}and (11.4 ± 0.3), respectively. Kinetic parameters acquired from data of interlaboratories by using heat-flow calorimetry, the averaged activation energy and frequency factor in logA(s{sup −1}) were (119.3 ± 11.3) kJ mol{sup −1}and (12.0 ± 0.2), respectively. On the analogy of results from adiabatic calorimetry, the activation energy and frequency factor in logA(s{sup −1}) were respectively averaged to be (122.4 ± 9.2) kJ mol{sup −1}and (11.8 ± 0.8). Five sets of kinetic models in relation to autocatalytic reactions are collected and discussed as well.

  7. The mechanism of interactions between tea polyphenols and porcine pancreatic alpha‐amylase: Analysis by inhibition kinetics, fluorescence quenching, differential scanning calorimetry and isothermal titration calorimetry

    Science.gov (United States)

    Sun, Lijun; Gidley, Michael J.

    2017-01-01

    Scope This study aims to use a combination of biochemical and biophysical methods to derive greater mechanistic understanding of the interactions between tea polyphenols and porcine pancreatic α‐amylase (PPA). Methods and results The interaction mechanism was studied through fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) and compared with inhibition kinetics. The results showed that a higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA. The red‐shift of maximum emission wavelength of PPA bound with some polyphenols indicated a potential structural unfolding of PPA. This was also suggested by the decreased thermostability of PPA with these polyphenols in DSC thermograms. Through thermodynamic binding analysis of ITC and inhibition kinetics, the equilibrium of competitive inhibition was shown to result from the binding of particularly galloylated polyphenols with specific sites on PPA. There were positive linear correlations between the reciprocal of competitive inhibition constant (1/K ic), quenching constant (K FQ) and binding constant (K itc). Conclusion The combination of inhibition kinetics, FQ, DSC and ITC can reasonably characterize the interactions between tea polyphenols and PPA. The galloyl moiety is an important group in catechins and theaflavins in terms of binding with and inhibiting the activity of PPA. PMID:28618113

  8. The mechanism of interactions between tea polyphenols and porcine pancreatic alpha-amylase: Analysis by inhibition kinetics, fluorescence quenching, differential scanning calorimetry and isothermal titration calorimetry.

    Science.gov (United States)

    Sun, Lijun; Gidley, Michael J; Warren, Frederick J

    2017-10-01

    This study aims to use a combination of biochemical and biophysical methods to derive greater mechanistic understanding of the interactions between tea polyphenols and porcine pancreatic α-amylase (PPA). The interaction mechanism was studied through fluorescence quenching (FQ), differential scanning calorimetry (DSC) and isothermal titration calorimetry (ITC) and compared with inhibition kinetics. The results showed that a higher quenching effect of polyphenols corresponded to a stronger inhibitory activity against PPA. The red-shift of maximum emission wavelength of PPA bound with some polyphenols indicated a potential structural unfolding of PPA. This was also suggested by the decreased thermostability of PPA with these polyphenols in DSC thermograms. Through thermodynamic binding analysis of ITC and inhibition kinetics, the equilibrium of competitive inhibition was shown to result from the binding of particularly galloylated polyphenols with specific sites on PPA. There were positive linear correlations between the reciprocal of competitive inhibition constant (1/Kic ), quenching constant (KFQ ) and binding constant (Kitc ). The combination of inhibition kinetics, FQ, DSC and ITC can reasonably characterize the interactions between tea polyphenols and PPA. The galloyl moiety is an important group in catechins and theaflavins in terms of binding with and inhibiting the activity of PPA. © 2017 The Authors. Molecular Nutrition & Food Research Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Heart rate recording method validated by whole body indirect calorimetry in 10-yr-old children.

    Science.gov (United States)

    Bitar, A; Vermorel, M; Fellmann, N; Bedu, M; Chamoux, A; Coudert, J

    1996-09-01

    The aim of the study was to validate the heart rate (HR) recording method against whole body indirect calorimetry in prepubertal children. Nineteen 10.5-yr-old healthy children (10 boys, 9 girls) participated in this study. HR and energy expenditure (EE) were recorded through laboratory tests. Individual relationships between HR and EE were computed (equation established in laboratory). Several models were tested and validated from 24-h measurements of EE and HR by whole body indirect calorimetry. The best fit was obtained with individual polynomial relationships. Mean differences between predicted (equation established in laboratory) and measured total daily EE averaged 7.6 +/- 20.1%. The causes of the differences and the means of improving the accuracy of the prediction equation are discussed.

  10. Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis

    Science.gov (United States)

    K. S., Nagapriya; Sinha, Shashank; Prashanth, R.; Poonacha, Samhitha; Chaudhry, Gunaranjan; Bhattacharya, Anandaroop; Choudhury, Niloy; Mahalik, Saroj; Maity, Sandip

    2017-02-01

    In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography. Using LCS, we have been able to detect ppm levels of dissolved gases without extracting them from the liquid. In this paper, we show the detection of dissolved acetylene in transformer oil in the mid infrared (MIR) wavelength (3021 nm) region.

  11. Kinetics of Enzymatic High-Solid Hydrolysis of Lignocellulosic Biomass Studied by Calorimetry

    DEFF Research Database (Denmark)

    Olsen, Søren Nymand; Rasmussen, Erik Lumby; McFarland, K.C.

    2011-01-01

    . In the current work, we have investigated the application of isothermal calorimetry to study the kinetics of enzymatic hydrolysis of two substrates (pretreated corn stover and Avicel) at high-solid contents (up to 29% w/w). It was found that the calorimetric heat flow provided a true measure of the hydrolysis...... rate with a detection limit of about 500 pmol glucose s−1. Hence, calorimetry is shown to be a highly sensitive real-time method, applicable for high solids, and independent on the complexity of the substrate. Dose–response experiments with a typical cellulase cocktail enabled a multidimensional...... (excess of attack points) at later stages (>10% conversion). This kinetic profile is interpreted as an increase in polymer end concentration (substrate for CBH) as the hydrolysis progresses, probably due to EG activity in the enzyme cocktail. Finally, irreversible enzyme inactivation did not appear...

  12. Modulated Temperature Differential Scanning Calorimetry Theoretical and Practical Applications in Polymer Characterisation

    CERN Document Server

    Reading, Mike

    2006-01-01

    MTDSC provides a step-change increase in the power of calorimetry to characterize virtually all polymer systems including curing systems, blends and semicrystalline polymers. It enables hidden transitions to be revealed, miscibility to be accurately assessed, and phases and interfaces in complex blends to be quantified. It also enables crystallinity in complex systems to be measured and provides new insights into melting behaviour. All of this is achieved by a simple modification of conventional DSC. In 1992 a new calorimetric technique was introduced that superimposed a small modulation on top of the conventional linear temperature program typically used in differential scanning calorimetry. This was combined with a method of data analysis that enabled the sample’s response to the linear component of the temperature program to be separated from its response to the periodic component. In this way, for the first time, a signal equivalent to that of conventional DSC was obtained simultaneously with a measure ...

  13. Mass production of PWO crystals for electromagnetic calorimetry peculiarities and prospects

    CERN Document Server

    Annenkov, A N; Kostylev, V; Lecoq, P

    2000-01-01

    This paper is devoted to mass production of the most popular now scintillation material in high energy physics. Among recently developed scintillation materials lead tungstate (PbWO/sub 4/, PWO) has already found applications in electromagnetic calorimetry in the CMS and ALICE collaborations at the LHC. The status of the crystal production, peculiarities of crystal machining and property certification, the distribution of scintillation parameters as well as long term stability of crystal scintillation properties will be discussed. (2 refs).

  14. Differential scanning calorimetry investigations on Eu-doped fluorozirconate-based glass ceramics.

    Science.gov (United States)

    Paßlick, C; Ahrens, B; Henke, B; Johnson, J A; Schweizer, S

    2010-12-01

    The properties of Eu-doped fluorochlorozirconate (FCZ) glass ceramics upon thermal processing and the influence of Eu-doping on the formation of BaCl(2) nanocrystals therein have been investigated. Differential scanning calorimetry indicates that higher Eu-doping shifts the crystallization peak of the nanocrystals in the glass to lower temperatures, while the glass transition temperature remains constant. The activation energy and the thermal stability parameters for the BaCl(2) crystallization are determined.

  15. Revisiting the streptavidin-biotin binding by using an aptamer and displacement isothermal calorimetry titration.

    Science.gov (United States)

    Kuo, Tai-Chih; Tsai, Ching-Wei; Lee, Peng-Chen; Chen, Wen-Yih

    2015-03-01

    The association constant of a well-known streptavidin-biotin binding has only been inferred from separately measured kinetic parameters. In a single experiment, we obtained Ka 1 × 10(12)  M(-1) by using a streptavidin-binding aptamer and ligand-displacement isothermal titration calorimetry. This study explores the challenges of determining thermodynamic parameters and the derived equilibrium binding affinity of tight ligand-receptor binding. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Combined laser calorimetry and photothermal technique for absorption measurement of optical coatings.

    Science.gov (United States)

    Li, Bincheng; Blaschke, Holger; Ristau, Detlev

    2006-08-10

    To the best of our knowledge, a combined sensitive technique employing both laser calorimetry and a surface thermal lens scheme for measuring absorption values of optical coatings is presented for the first time. Laser calorimetric and pulsed surface thermal lens signals are simultaneously obtained with a highly reflecting UV coating sample irradiated at 193 nm. The advantages and potential applications of the combined technique and the experimental factors limiting the measurement sensitivity are discussed.

  17. Application of calorimetry in evaluation of phase transformations in the selected hypoeutectic silumins

    Directory of Open Access Journals (Sweden)

    J. Szymszal

    2009-04-01

    Full Text Available The investigations of phase transformations described in this study were carried out on hypoeutectic alloys from the Al-Si during heating and cooling. The determination and analysis of characteristic temperature values from the solidification range was made by the DSC method in calorimetric investigations carried out on a high-temperature multi HTC Setaram scanning calorimeter. Applying the lever rule, the phase composition of the examined slumins was calculated and compared with the results of DSC calorimetry.

  18. Determination of the aggregation number for micelles by isothermal titration calorimetry

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Holm, Rene; Westh, Peter

    2014-01-01

    Isothermal titration calorimetry (ITC) has previously been applied to estimate the aggregation number (n), Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) of micellization. However, some difficulties of micelle characterization by ITC still remain; most micelles have aggregation numbers...... insight into optimal design of titration protocols for micelle characterization. By applying the new method, the aggregation number of sodium dodecyl sulphate and glycochenodeoxycholate was determined at concentrations around their critical micelle concentration (CMC)...

  19. CALOR2012 XVth International Conference on Calorimetry in High Energy Physics

    Energy Technology Data Exchange (ETDEWEB)

    Akchurin, Nural .

    2015-05-04

    The International Conferences on Calorimetry in High Energy Physics, or the CALOR series, have always been where the calorimeter experts come together to review the state of calorimetry and bring forth new ideas every two years. The fteenth conference, CALOR2012, in Santa Fe was no exception. Although they were built roughly a decade ago, we are now witnessing the exceptional power of the LHC calorimeters and the crucial role they have been playing in the discovery of the 125 GeV Higgs-like boson. As we ruminate on the coming generation of experiments at the next (linear) collider and on the upgrades at the LHC, we are heartened by the substantial advances we made in calorimetry in the last decade. These advances will certainly help uncover new physics in the years to come, not only at colliders but also in astroparticle experiments that take advantage of natural elements such as air, water, and ice. The proceedings were published by the IOP in Journal of Physics, Vol 404 2011. The conference web site is calor2012.ttu.edu.

  20. Reading and listening to music increase resting energy expenditure during an indirect calorimetry test.

    Science.gov (United States)

    Snell, Blaire; Fullmer, Susan; Eggett, Dennis L

    2014-12-01

    Indirect calorimetry is often done early in the morning in a fasting state, with the subject unshowered and abstained from caffeine or other stimulants. Subjects often fall asleep, resulting in measurement of a sleeping metabolic rate rather than a resting metabolic rate. The objective of this study was to determine whether listening to self-selected relaxing music or reading an electronic device or magazine affects resting energy expenditure (REE) during measurement in healthy adults. A randomized trial comparing three different conditions (ie, resting, reading, and listening to music) was performed. Sixty-five subjects (36 female and 29 male) were used in final data analysis. Inclusion criteria included healthy subjects between the ages of 18 and 50 years with a stable weight. Exclusion criteria included pregnant or lactating women or use of medications known to affect metabolism. Results showed that reading either a magazine or an electronic device significantly increased REE by 102.7 kcal/day when compared with resting (Pmusic increased REE by 27.6 kcal/day compared with rest (P=0.0072). Based on our results, we recommend subjects refrain from reading a magazine or electronic device during an indirect calorimetry test. Whether or not the smaller difference found while listening to music is practically significant would be a decision for the indirect calorimetry test administrator. Copyright © 2014 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.

  1. Picosecond calorimetry

    DEFF Research Database (Denmark)

    Georgiou, Panayiotis; Vincent, Jonathan; Andersson, Magnus

    2006-01-01

    the photochemical of interest but also from the embedding solvent matrix. To experimentally characterize the x-ray diffraction signal deriving from the solvent alone we performed time-resolved diffraction studies of a pure liquid sample over a time domain from -250 ps to 2.5 μs. Multiphoton excitation was used......Liquid phase time-resolved x-ray diffraction with 100 ps resolution has recently emerged as a powerful technique for probing the structural dynamics of transient photochemical species in solution. It is intrinsic to the method, however, that a structural signal is observed not only from...... to rapidly heat liquid C H2 Cl2 using UV pulses of 100 fs duration. A significant x-ray diffraction signal is visible prior to the onset of thermal expansion, which characterizes a highly compressed superheated liquid. Liquid C H2 Cl2 then expands as a shock wave propagates through the sample...

  2. Differential scanning calorimetry in life science: thermodynamics, stability, molecular recognition and application in drug design.

    Science.gov (United States)

    Bruylants, G; Wouters, J; Michaux, C

    2005-01-01

    All biological phenomena depend on molecular recognition, which is either intermolecular like in ligand binding to a macromolecule or intramolecular like in protein folding. As a result, understanding the relationship between the structure of proteins and the energetics of their stability and binding with others (bio)molecules is a very interesting point in biochemistry and biotechnology. It is essential to the engineering of stable proteins and to the structure-based design of pharmaceutical ligands. The parameter generally used to characterize the stability of a system (the folded and unfolded state of the protein for example) is the equilibrium constant (K) or the free energy (deltaG(o)), which is the sum of enthalpic (deltaH(o)) and entropic (deltaS(o)) terms. These parameters are temperature dependent through the heat capacity change (deltaCp). The thermodynamic parameters deltaH(o) and deltaCp can be derived from spectroscopic experiments, using the van't Hoff method, or measured directly using calorimetry. Along with isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC) is a powerful method, less described than ITC, for measuring directly the thermodynamic parameters which characterize biomolecules. In this article, we summarize the principal thermodynamics parameters, describe the DSC approach and review some systems to which it has been applied. DSC is much used for the study of the stability and the folding of biomolecules, but it can also be applied in order to understand biomolecular interactions and can thus be an interesting technique in the process of drug design.

  3. Resistive Micromegas for sampling calorimetry, a study of charge-up effects

    Energy Technology Data Exchange (ETDEWEB)

    Chefdeville, M., E-mail: chefdevi@lapp.in2p3.fr [LAPP, Université de Savoie, CNRS/IN2P3, Annecy-Le-Vieux (France); Karyotakis, Y. [LAPP, Université de Savoie, CNRS/IN2P3, Annecy-Le-Vieux (France); Geralis, T. [INP, NCSR Demokritos, Athens (Greece); Titov, M. [IRFU, Saclay CEA, Gif-sur-Yvette (France)

    2016-07-11

    Micromegas, as a proportional and compact gaseous detector, is well suited for sampling calorimetry. The limitation of occasional sparking has now been lifted by means of resistive electrodes but at the cost of current-dependent charge-up effects. These effects are studied in this contribution, with an emphasis on gain variations during operation at high particle rate and under heavy ionisation. Results are reproduced by a simple model of charging-up which will be used for detector design optimisation in the future.

  4. Using isothermal titration calorimetry to determine thermodynamic parameters of protein-glycosaminoglycan interactions.

    Science.gov (United States)

    Dutta, Amit K; Rösgen, Jörg; Rajarathnam, Krishna

    2015-01-01

    It has now become increasingly clear that a complete atomic description of how biomacromolecules recognize each other requires knowledge not only of the structures of the complexes but also of how kinetics and thermodynamics drive the binding process. In particular, such knowledge is lacking for protein-glycosaminoglycan (GAG) complexes. Isothermal titration calorimetry (ITC) is the only technique that can provide various thermodynamic parameters-enthalpy, entropy, free energy (binding constant), and stoichiometry-from a single experiment. Here we describe different factors that must be taken into consideration in carrying out ITC titrations to obtain meaningful thermodynamic data of protein-GAG interactions.

  5. Determination of magnetic characteristics of nanoparticles by low-temperature calorimetry methods

    Energy Technology Data Exchange (ETDEWEB)

    Ugulava, A.; Toklikishvili, Z. [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Chkhaidze, S., E-mail: simon.chkhaidze@tsu.ge [Department of Physics, I.Javakhishvili Tbilisi State University,I.Chavchavadze av. 3, 0179 Tbilisi, Georgia (United States); Kekutia, Sh. [V. Chavchanidze Institute of Cybernetics, at the Technical State University, S. Euli str. 5, 0186 Tbilisi, Georgia (United States)

    2017-05-15

    At low temperatures, the heat capacity of a superparamagnetic “ideal gas” determined by magnetic degrees of freedom can greatly exceed the lattice heat capacity. It is shown that in the presence of an external magnetic field, the temperature dependence of the magnetic part of the heat capacity has two maxima. The relations between the temperature at which these maxima are achieved, the magnetic moment of the nanoparticles and the magnetic anisotropy constant have been obtained. Measuring the heat capacity maxima temperatures by low-temperature calorimetry methods and using the obtained relations, we can obtain the numerical values both of the magnetic moment of nanoparticles and the magnetic anisotropy constants.

  6. Application of calorimetry in evaluation of phase transformations in the selected hypoeutectic silumins

    Directory of Open Access Journals (Sweden)

    J. Piątkowski

    2008-12-01

    Full Text Available The investigations of phase transformations described in this study were carried out on hypoeutectic alloys from the Al-Si system (AlSi3, AlSi6 and AlSi9 during heating and cooling. The determination and analysis of characteristic temperature values from the solidification range was made by the DSC method in calorimetric investigations carried out on a high-temperature multi HTC scanning calorimeter. Applying the lever rule, the phase composition of the examined silumins was calculated and compared with the results of DSC calorimetry, obtaining a good correlation of the results.

  7. Methodology of hot nucleus calorimetry and thermometry produced by nuclear reactions around Fermi energies; Methodologie de la calorimetrie et de la thermometrie des noyaux chauds formes lors de collisions nucleaires aux energies de Fermi

    Energy Technology Data Exchange (ETDEWEB)

    Vient, E

    2006-12-15

    This work deals with the calorimetry and thermometry of hot nuclei produced in collisions Xe + Sn between 25 and 100 MeV/u. The apparatus for hot nucleus physical characterization is the 4{pi} detector array Indra. This study was made by using the event generators Gemini, Simon and Hipse and a data-processing filter simulating the complete operation of the multi-detector. The first chapter presents the different ways of producing hot nuclei. In the second and third chapters, the author presents a critical methodological study of calorimetry and thermometry applied to hot nuclei, different methods are reviewed, their accuracy and application range are assessed. All the calorimetry methods rely on the assumption that we are able to discriminate decay products of the hot nucleus from evaporated particles. In the fourth chapter, the author gives some ways of improving calorimetry characterization of the hot nucleus. An alternative method of calorimetry is proposed in the fifth chapter, this method is based on the experimental determination of an evaporation probability that is deduced from the physical characteristics of the particles present in a restricted domain of the space of velocities.

  8. Interaction of fengycin with stratum corneum mimicking model membranes: a calorimetry study.

    Science.gov (United States)

    Eeman, Marc; Olofsson, Gerd; Sparr, Emma; Nasir, Mehmet Nail; Nylander, Tommy; Deleu, Magali

    2014-09-01

    Based on its outstanding antifungal properties, it is reasonable to believe that fengycin might be efficient to topically treat localized dermatomycoses. Since most of the fungi species involved in the formation of those mycotic skin diseases colonize primarily the stratum corneum (SC), studying the interaction between fengycin and SC-mimicking lipid membranes is a primary step to determine the potential of fengycin to overcome the physical barrier of the skin. In this respect, multilamellar lipid vesicles (MLVs), with a lipid composition mimicking that of the SC, were prepared and characterized by differential scanning calorimetry (DSC). The critical micelle concentration (CMC) of fengycin was also assessed under skin conditions and found to be 1.2±0.1μM. The molecular interactions of fengycin with SC-mimicking MLVs were investigated by both DSC and isothermal titration calorimetry (ITC). Results showed that the interactions were considerably affected by changes in lipid phase behaviour. At 40°C and below, fengycin induced exothermic changes in the lipid structures suggesting that less-ordered lipid domains became more-ordered in presence of fengycin. At 60°C, clearly endothermic interaction enthalpies were observed, which could arise from the "melting" of remaining solid domains enriched in high melting lipids that without fengycin melt at higher temperatures. Copyright © 2014 Elsevier B.V. All rights reserved.

  9. Thin-film calorimetry. In-situ characterization of materials for lithium-ion batteries

    Energy Technology Data Exchange (ETDEWEB)

    Omelcenko, Alexander; Wulfmeier, Hendrik; Albrecht, Daniel; Fritze, Holger [Clausthal Univ. of Technology, Goslar (Germany). Inst. of Energy Research and Physical Technologies; El Mofid, Wassima; Ivanov, Svetlozar; Bund, Andreas [Ilmenau Univ. of Technology (Germany). Dept. of Electrochemistry

    2017-11-15

    Thin-film calorimetry allows for qualitative and quantitative in-situ analysis of thermodynamic properties of thin films and thin-film systems from room temperature up to 1000 C. It is based on highly sensitive piezoelectric langasite resonators which serve simultaneously as planar temperature sensors and substrates for the films of interest. Generation or consumption of heat during phase transformations of the films cause deviations from the regular course of the resonance frequency. Thermodynamic data such as phase transformation temperatures and enthalpies are extracted from these deviations. Thin-film calorimetry on Sn and Al thin films is performed to prove the concept. The results demonstrate high reproducibility of the measurement approach and are in agreement with literature data obtained by established calorimetric techniques. The calibration of the system is done in different atmospheres by application of defined heat pulses via heating structures. The latter replace the films of interest and simulate phase transformations to provide detailed analysis of the heat transfer mechanisms occurring in the measurement system. Based on this analysis, a data evaluation concept is developed. Application-relevant studies are performed on thin films of the lithium-ion battery materials NMC(A), NCA, LMO, and MoS{sub 2}. Their phase transformation temperatures and enthalpies are evaluated in oxidizing and reducing atmospheres. Furthermore, their thermodynamic stability ranges are presented. Finally, measurements on all-solid-state thin-film batteries during electrochemical cycling are performed. They demonstrate the suitability of the system for in-situ investigations.

  10. Energy Expenditure in Adolescents with Cerebral Palsy: Comparison of the Sensewear Armband and Indirect Calorimetry.

    Science.gov (United States)

    Koehler, Karsten; Abel, Thomas; Wallmann-Sperlich, Birgit; Dreuscher, Annika; Anneken, Volker

    2014-05-09

    Inactivity and overweight are major health concerns in children and adolescents with disabilities. Methods for the assessment of activity and energy expenditure may be affected negatively by the underlying disability, especially when motor function is impaired. The purpose of this study was to assess the validity of the SenseWear armband in adolescents with cerebral palsy and hemiparesis. Ten volunteers (age: 13.4 ± 1.6 years) were equipped with SenseWear armbands (Model MF, BodyMedia, Pittsburgh, PA) on the hemiparetic and non-hemiparetic side of the body. Energy expenditure was measured at rest and during treadmill exercise (speed range: 0.85 to 2.35 m/s). Indirect calorimetry served as independent reference method. The mean error was between -0.6 and 0.8 kcal/min and there were no significant differences between SenseWear and indirect calorimetry at any speed. Differences between body sides in expenditure (mean: -0.2 to 0.0 kcal/min) and step count (mean: -3.4 to 9.7 steps/min) were not significant. The validity of the SenseWear armband does not appear to be negatively affected by cerebral palsy during laboratory treadmill exercise. Future field studies are necessary to assess the validity and practicability energy expenditure and physical activity in children and adolescents with physical disabilities.

  11. Resting energy expenditure and body composition in children with cancer: indirect calorimetry and bioimpedance analysis

    Directory of Open Access Journals (Sweden)

    M. V. Konovalova

    2014-07-01

    Full Text Available Resting energy expenditure (REE by indirect calorimetry and body composition by bioimpedance analysis are studied in three groups of children aged 5–18 years. Group 1 (n = 181 – patients in remission of cancer, group 2 (n = 55 – children with oncology diseases receiving chemotherapy or who are in the early period after hematopoietic stem cell transplantation, group 3 (n = 63 – children with non-malignant diseases of the gastrointestinal tract. To eliminate the influence of age and gender on the intergroup comparisons, body composition parameters were expressed as standardized values (z-scores relative to a reference group of healthy Russian children (n = 138,191. Group 1 was characterized by excess fat content with intact lean body mass, and groups 2 and 3 by protein depletion, more pronounced in Group 2 with a higher percentage of body fat. All used conventional formulas (WHO, Harris–Benedict and others in groups 1 and 3 underestimated REE as compared with indirect calorimetry. A new formula for REE, giving an unbiased estimate in the group 1 was proposed: REE (kcal/day = 28.7 × BCM (kg +10.5 × Height (cm – 38.6 × Age (years – 134, where BCM – body cell mass according to bioimpedance analysis (R2 = 0.67, the standard deviation of 196 kcal/day.

  12. Temperature stability of proteins: Analysis of irreversible denaturation using isothermal calorimetry.

    Science.gov (United States)

    Schön, Arne; Clarkson, Benjamin R; Jaime, Maria; Freire, Ernesto

    2017-11-01

    The structural stability of proteins has been traditionally studied under conditions in which the folding/unfolding reaction is reversible, since thermodynamic parameters can only be determined under these conditions. Achieving reversibility conditions in temperature stability experiments has often required performing the experiments at acidic pH or other nonphysiological solvent conditions. With the rapid development of protein drugs, the fastest growing segment in the pharmaceutical industry, the need to evaluate protein stability under formulation conditions has acquired renewed urgency. Under formulation conditions and the required high protein concentration (∼100 mg/mL), protein denaturation is irreversible and frequently coupled to aggregation and precipitation. In this article, we examine the thermal denaturation of hen egg white lysozyme (HEWL) under irreversible conditions and concentrations up to 100 mg/mL using several techniques, especially isothermal calorimetry which has been used to measure the enthalpy and kinetics of the unfolding and aggregation/precipitation at 12°C below the transition temperature measured by DSC. At those temperatures the rate of irreversible protein denaturation and aggregation of HEWL is measured to be on the order of 1 day-1 . Isothermal calorimetry appears a suitable technique to identify buffer formulation conditions that maximize the long term stability of protein drugs. © 2017 Wiley Periodicals, Inc.

  13. On the value of c: can low affinity systems be studied by isothermal titration calorimetry?

    Science.gov (United States)

    Turnbull, W Bruce; Daranas, Antonio H

    2003-12-03

    Isothermal titration calorimetry (ITC) allows the determination of DeltaG degrees, DeltaH degrees, and DeltaS degrees from a single experiment and is thus widely used for studying binding thermodynamics in both biological and synthetic supramolecular systems. However, it is widely believed that it is not possible to derive accurate thermodynamic information from ITC experiments in which the Wiseman "c" parameter (which is the product of the receptor concentration and the binding constant, K(a)) is less than ca. 10, constraining its use to high affinity systems. Herein, experimental titrations and simulated data are used to demonstrate that this dogma is false, especially for low affinity systems, assuming that (1) a sufficient portion of the binding isotherm is used for analysis, (2) the binding stoichiometry is known, (3) the concentrations of both ligand and receptor are known with accuracy, and (4) there is an adequate level of signal-to-noise in the data. This study supports the validity of ITC for determining the value of K(a) and, hence, DeltaG degrees from experiments conducted under low c conditions but advocates greater caution in the interpretation of values for DeltaH degrees. Therefore, isothermal titration calorimetry is a valid and useful technique for studying biologically and synthetically important low affinity systems.

  14. Resistivity and AC calorimetry measurements on CeNiGe{sub 2} under pressure

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, A.T. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan)]. E-mail: alex@djebel.mp.es.osaka-u.ac.jp; Muramatsu, T. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Miyake, A. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Kaczorowski, D. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Bukowski, Z. [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Kagayama, T. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan); Shimizu, K. [KYOKUGEN, Osaka University, Toyonaka, Osaka 560-8531 (Japan)

    2007-03-15

    We present resistivity and AC calorimetry measurements of single crystalline CeNiGe{sub 2} under high pressure and low temperature in a diamond anvil cell. CeNiGe{sub 2} is a highly anisotropic, antiferromagnetic Kondo system at ambient pressure, located close to the boundary with non-magnetic systems. It has two ordering temperatures, T{sub N1}=3.9K and T{sub N2}=3.2K, which are suppressed under pressure. Between 0.7 and 1.4GPa only a single transition was identified, with T{sub N} reaching 1.9K by 1.4 GPa. At 1.9GPa two transitions could again be seen by AC calorimetry at 2.0 and 1.3K, accompanied by a qualitative change in the behaviour of the resistivity. The Sommerfeld coefficient showed a maximum of 755mJmol{sup -1}K{sup -2} at 1.4GPa, up from 448mJmol{sup -1}K{sup -2} at close to ambient pressure. The residual resistivity was found to decrease sharply above 1.4GPa after an initial increase with pressure.

  15. A High-Throughput Biological Calorimetry Core: Steps to Startup, Run, and Maintain a Multiuser Facility.

    Science.gov (United States)

    Yennawar, Neela H; Fecko, Julia A; Showalter, Scott A; Bevilacqua, Philip C

    2016-01-01

    Many labs have conventional calorimeters where denaturation and binding experiments are setup and run one at a time. While these systems are highly informative to biopolymer folding and ligand interaction, they require considerable manual intervention for cleaning and setup. As such, the throughput for such setups is limited typically to a few runs a day. With a large number of experimental parameters to explore including different buffers, macromolecule concentrations, temperatures, ligands, mutants, controls, replicates, and instrument tests, the need for high-throughput automated calorimeters is on the rise. Lower sample volume requirements and reduced user intervention time compared to the manual instruments have improved turnover of calorimetry experiments in a high-throughput format where 25 or more runs can be conducted per day. The cost and efforts to maintain high-throughput equipment typically demands that these instruments be housed in a multiuser core facility. We describe here the steps taken to successfully start and run an automated biological calorimetry facility at Pennsylvania State University. Scientists from various departments at Penn State including Chemistry, Biochemistry and Molecular Biology, Bioengineering, Biology, Food Science, and Chemical Engineering are benefiting from this core facility. Samples studied include proteins, nucleic acids, sugars, lipids, synthetic polymers, small molecules, natural products, and virus capsids. This facility has led to higher throughput of data, which has been leveraged into grant support, attracting new faculty hire and has led to some exciting publications. © 2016 Elsevier Inc. All rights reserved.

  16. Monitoring of butter and animal fat oxidation stability by differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Jasminka Sadadinović

    2005-07-01

    Full Text Available Oxidation of fat is one of the basic reactions which causes the depletion of butter and animal fat quality as well as other products containing them. Since the most of reaction products of fat oxidation are harmful for consumers' health, inadequate and scarce monitoring of edible fats and fat containing products quality, presents increased health risk as well as financial loss for the producers. In fat oxidation stability estimation, standard chemical methods were used (iodine number, acid number, peroxide number, anisidine number etc., which require time and chemical usage. Differential scanning calorimetry (DSC analysis presents the simple and efficient way for butter and animal fats oxidation stability estimation. Laboratory investigations were performed to monitor oxidation stability of butter and animal fat in fresh state, as well as in spent phase, used in frying process. The results obtained were compared to the results of standard chemical analysis, and they confirmed the reproducibility and applicability of differential scanning calorimetry in oxidation stability of butter and animal fats monitoring.

  17. PREFACE: 16th International Conference on Calorimetry in High Energy Physics (CALOR 2014)

    Science.gov (United States)

    Novotny, Rainer W.

    2015-02-01

    The XVIth International Conference on Calorimetry in High Energy Physics - CALOR 2014 - was held in Giessen, Germany from 6-11 April 2014 at the Science Campus of the University. It was hosted by the Justus-Liebig-University and the HIC for FAIR Helmholtz International Center. The series of conferences on calorimetry were started in 1990 at Fermilab and are focusing primarily on operating and future calorimeter systems within the Hadron and High-Energy Physics community without neglecting the impact on other fields such as Astrophysics or Medical Imaging. Confirmed by the impressive list of over 70 oral presentations, 5 posters and over 100 attendees, the field of calorimetry appears alive and attractive. The present volume contains the written contributions of almost all presentations which can be found at http://calor2014.de. Time slots of 15 or 30 minutes including discussion were allocated. The conference was accompanied by a small exhibition of several industrial companies related to the field. The day before the opening of the scientific program, Richard Wigmans gave an excellent and vivid tutorial on basic aspects on calorimetry meant as an introduction for students and conference attendees new in the field. The opening ceremony was used to give an impression of the present and future status and the scientific program of the new FAIR facility nearby at Darmstadt presented by Klaus Peters from GSI. The conference program of the first day was dedicated to the performance and required future upgrade of the LHC experiments, dominated by ATLAS, CMS and LHCb. The program of the next day contained specific aspects on electronics and readout as well as calorimetry in outer space. Several contributions discussed in detail new concepts for hadron calorimeters within the CALICE collaboration completed by a session on sampling calorimeters. The next sections were dedicated to operating and future calorimeters at various laboratories and covering a wide range of

  18. Use of isothermal titration calorimetry to study the interaction of short-chain alcohols with lipid membranes

    DEFF Research Database (Denmark)

    Trandum, Christa; Westh-Andersen, Peter; Jørgensen, Kent

    1999-01-01

    of short-chain alcohols on Lipid bilayers. isothermal titration calorimetry (ITC) has been used to determine the energy involved in the association of the alcohols with lipid bilayers. Pure unilamellar DMPC liposomes and DMPC liposomes incorporated with different amounts of cholesterol, sphingomyelin...... dependent on the lipid bilayer composition. In the presence of high concentrations of cholesterol, the binding enthalpy of ethanol is decreased, whereas the presence of ceramides enhances the enthalpic response of the lipid bilayer to ethanol. Isothermal titration calorimetry offers a new methodology...

  19. Isothermal titration calorimetry and surface plasmon resonance allow quantifying substrate binding to different binding sites of Bacillus subtilis xylanase

    DEFF Research Database (Denmark)

    Cuyvers, Sven; Dornez, Emmie; Abou Hachem, Maher

    2012-01-01

    Isothermal titration calorimetry and surface plasmon resonance were tested for their ability to study substrate binding to the active site (AS) and to the secondary binding site (SBS) of Bacillus subtilis xylanase A separately. To this end, three enzyme variants were compared. The first was a cat......Isothermal titration calorimetry and surface plasmon resonance were tested for their ability to study substrate binding to the active site (AS) and to the secondary binding site (SBS) of Bacillus subtilis xylanase A separately. To this end, three enzyme variants were compared. The first...

  20. Determination of ice content in hardened concrete by low-temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn; Geiker, Mette Rica

    2014-01-01

    on the accumulated heat curves measured in the freezing and the melting process. Second, the ‘C-baseline’ is discussed in which a calculated baseline is used where the heat capacity of both water and ice and the phase changing behaviour under different testing temperatures are considered. It turns out that both...... calculate the ice contents at different temperatures in the freezing and melting process. It should be noted that there is no general agreement on how to obtain the important temperature dependence of the heat of fusion of water confined in small pores. By performing comparison studies, the present study......Low-temperature calorimetry has been used to determine the ice content in concrete at different temperatures when exposed to low-temperature environments. However, the analysis of the ice content from the measured data of heat flow is not straightforward. In this study, two important factors...

  1. Coulometry and Calorimetry of Electric Double Layer Formation in Porous Electrodes

    Science.gov (United States)

    Janssen, Mathijs; Griffioen, Elian; Biesheuvel, P. M.; van Roij, René; Erné, Ben

    2017-10-01

    Coulometric measurements on salt-water-immersed nanoporous carbon electrodes reveal, at a fixed voltage, a charge decrease with increasing temperature. During far-out-of-equilibrium charging of these electrodes, calorimetry indicates the production of both irreversible Joule heat and reversible heat, the latter being associated with entropy changes during electric double layer (EDL) formation in the nanopores. These measurements grant experimental access—for the first time—to the entropic contribution of the grand potential; for our electrodes, this amounts to roughly 25% of the total grand potential energy cost of EDL formation at large applied potentials, in contrast with point-charge model calculations that predict 100%. The coulometric and calorimetric experiments show a consistent picture of the role of heat and temperature in EDL formation and provide hitherto unused information to test against EDL models.

  2. Building a graphite calorimetry system for the dosimetry of therapeutic x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Kim, In Jung; Kim, Byoung Chul; Kim, Joong Hyun; Chung, Jae Pil; Kim, Hyun Moon; Yi, Chul Young [Korea Research Institute of Standards and Science, Daejeon (Korea, Republic of)

    2017-06-15

    A graphite calorimetry system was built and tested under irradiation. The noise level of the temperature measurement system was approximately 0.08 mK (peak to peak). The temperature of the core part rose by approximately 8.6 mK at 800 MU (monitor unit) for 6-MV X-ray beams, and it increased as X-ray energy increased. The temperature rise showed less spread when it was normalized to the accumulated charge, as measured by an external monitoring chamber. The radiation energy absorbed by the core part was determined to have values of 0.798 J/μC, 0.389 J/μC, and 0.352 J/μC at 6 MV, 10 MV, and 18 MV, respectively. These values were so consistent among repeated runs that their coefficient of variance was less than 0.15%.

  3. Conductivity, calorimetry and phase diagram of the NaHSO4–KHSO4 system

    DEFF Research Database (Denmark)

    Hind, Hamma-Cugny; Rasmussen, Søren Birk; Rogez, J.

    2006-01-01

    Physico-chemical properties of the binary system NaHSO4-KHSO4 were studied by calorimetry and conductivity, The enthalpy of mixing has been measured at 505 K in the full composition range and the phase diagram calculated. The phase diagram has also been constructed from phase transition...... temperatures obtained by conductivity for 10 different compositions and by differential thermal analysis. The phase diagram is of the simple eutectic type, where the eutectic is found to have the composition Χ(KHSO4)=0.44 (melting point ≈ 406 K). The conductivities in the liquid region have been fitted...... to polynomials of the form κ(X)=A(X)+B(X)(T-Tm)+C(X)(T-Tm)2, where Tm is the intermediate temperature of the measured temperature range and X, the mole fraction of KHSO4. The possible role of this binary system as a catalyst solvent is also discussed. (C) 2005 Elsevier B.V. All rights reserved....

  4. Measurement and Model Validation of Nanofluid Specific Heat Capacity with Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Harry O'Hanley

    2012-01-01

    Full Text Available Nanofluids are being considered for heat transfer applications; therefore it is important to know their thermophysical properties accurately. In this paper we focused on nanofluid specific heat capacity. Currently, there exist two models to predict a nanofluid specific heat capacity as a function of nanoparticle concentration and material. Model I is a straight volume-weighted average; Model II is based on the assumption of thermal equilibrium between the particles and the surrounding fluid. These two models give significantly different predictions for a given system. Using differential scanning calorimetry (DSC, a robust experimental methodology for measuring the heat capacity of fluids, the specific heat capacities of water-based silica, alumina, and copper oxide nanofluids were measured. Nanoparticle concentrations were varied between 5 wt% and 50 wt%. Test results were found to be in excellent agreement with Model II, while the predictions of Model I deviated very significantly from the data. Therefore, Model II is recommended for nanofluids.

  5. Differential scanning calorimetry predicts the critical quality attributes of amorphous glibenclamide

    DEFF Research Database (Denmark)

    Mah, Pei T; Laaksonen, Timo; Rades, Thomas

    2015-01-01

    Selection of a crystallinity detection tool that is able to predict the critical quality attributes of amorphous formulations is imperative for the development of process control strategies. The main aim of this study was to determine the crystallinity detection tool that best predicts the critical...... quality attributes (i.e. physical stability and dissolution behaviour) of amorphous material. Glibenclamide (model drug) was milled for various durations using a planetary mill and characterised using Raman spectroscopy and differential scanning calorimetry (DSC). Physical stability studies upon storage...... and plateaus were reached after milling for certain periods of time (physical stability - 150min; dissolution - 120min). The residual crystallinity which was detectable with DSC (onset of crystallisation), but not with Raman spectroscopy, adversely affected the critical quality attributes of milled...

  6. Characterization of Thermal Behavior of Epoxy Composites Reinforced with Curaua Fibers by Differential Scanning Calorimetry

    Science.gov (United States)

    Barcelos, Mariana A.; Ribeiro, Carolina Gomes D.; Ferreira, Jordana; Vieira, Janaina da S.; Margem, Frederico M.; Monteiro, Sergio N.

    Epoxy composites reinforced with natural lignocellulosic fibers have, in recent times, been gaining attention in engineering areas as lighter and cheaper alternatives for traditional composites such as the "fiberglass". The curaua fiber is the one strongest today being considered as reinforcement of composites for automobile interior parts. In fact, several studies are currently being dedicated to curaua fiber composites since physical and mechanical properties are required for practical uses. In this work, the thermal behavior of epoxy composites reinforced with up to 30 % in volume of curaua fibers was investigated by differential scanning calorimetry, DSC. The results showed endothermic and exothermic events associated with water release and possible molecular chain amorphous transformation. Comparison with similar composites permitted to propose mechanism that explains this DSC thermal behavior.

  7. Direct Coupling of SiPMs to Scintillator Tiles for Imaging Calorimetry and Triggering

    CERN Document Server

    Simon, Frank; Joram, Christian

    2010-01-01

    The recent availability of blue sensitive silicon photomultipliers allows the direct readout of blue emitting plastic scintillator tiles without the use of a wavelength shifting fiber. Such directly read out tiles, without light guides, are attractive for the use in highly granular calorimeters that use large numbers of individual cells and in other applications where very compact designs are needed. However, the total signal amplitude and the uniformity of the response can be problematic in such cases. We have developed a scanning setup to investigate the response of scintillator tiles with SiPM readout in detail. It was used to develop optimized scintillator tile geometries for highly granular hadronic calorimetry at future colliders and to investigate the feasibility of a SiPM readout for the trigger of the ATLAS ALFA luminosity detectors. We report on results obtained with specialized scintillator tile geometries, discuss first results obtained with directly coupled SiPM readout of the ATLAS ALFA trigger ...

  8. A digital Front-End and Readout MIcrosystem for calorimetry at LHC

    CERN Multimedia

    2002-01-01

    % RD-16 A Digital Front-End and Readout Microsystem for Calorimetry at LHC \\\\ \\\\Front-end signal processing for calorimetric detectors is essential in order to achieve adequate selectivity in the trigger function of an LHC experiment, with data identification and compaction before readout being required in the harsh, high rate environment of a high luminosity hadron machine. Other crucial considerations are the extremely wide dynamic range and bandwidth requirements, as well as the volume of data to be transferred to following stages of the trigger and readout system. These requirements are best met by an early digitalization of the detector information, followed by integrated digital signal processing and buffering functions covering the trigger latencies.\\\\ \\\\The FERMI (Front-End Readout MIcrosystem) is a digital implementation of the front-end and readout electronic chain for calorimeters. It is based on dynamic range compression, high speed A to D converters, a fully programmable pipeline/digital filter c...

  9. The oxidation of aluminum at high temperature studied by Thermogravimetric Analysis and Differential Scanning Calorimetry.

    Energy Technology Data Exchange (ETDEWEB)

    Coker, Eric Nicholas

    2013-10-01

    The oxidation in air of high-purity Al foil was studied as a function of temperature using Thermogravimetric Analysis with Differential Scanning Calorimetry (TGA/DSC). The rate and/or extent of oxidation was found to be a non-linear function of the temperature. Between 650 and 750 ÀC very little oxidation took place; at 850 ÀC oxidation occurred after an induction period, while at 950 ÀC oxidation occurred without an induction period. At oxidation temperatures between 1050 and 1150 ÀC rapid passivation of the surface of the aluminum foil occurred, while at 1250 ÀC and above, an initial rapid mass increase was observed, followed by a more gradual increase in mass. The initial rapid increase was accompanied by a significant exotherm. Cross-sections of oxidized specimens were characterized by scanning electron microscopy (SEM); the observed alumina skin thicknesses correlated qualitatively with the observed mass increases.

  10. Design and first measurements of an alternative calorimetry chamber for the HZB quadrupole resonator

    CERN Document Server

    Keckert, Sebastian; Knobloch, Jens; Kugeler, Oliver

    2015-01-01

    The systematic research on superconducting thin films requires dedicated testing equipment. The Quadrupole Resonator (QPR) is a specialized tool to characterize the superconducting RF properties of circular planar samples. A calorimetric measurement of the RF surface losses allows the surface resistance to be measured with sub nano-ohm resolution. This measurement can be performed over a wide temperature and magnetic field range, at frequencies of 433, 866 and 1300 MHz. The system at Helmholtz-Zentrum Berlin (HZB) is based on a resonator built at CERN and has been optimized to lower peak electric fields and an improved resolution. In this paper the design of an alternative calorimetry chamber is presented, providing flat samples for coating which are easy changeable. All parts are connected by screwing connections and no electron beam welding is required. Furthermore this design enables exchangeability of samples between the resonators at HZB and CERN. First measurements with the new design show ambiguous r...

  11. Thermodynamic and kinetic properties of interpolymer complexes assessed by isothermal titration calorimetry and surface plasmon resonance.

    Science.gov (United States)

    Bizley, Samuel C; Williams, Adrian C; Khutoryanskiy, Vitaliy V

    2014-11-07

    Interpolymer complexes (IPCs) formed between complimentary polymers in solution have shown a wide range of applications from drug delivery to biosensors. This work describes the combined use of isothermal titration calorimetry and surface plasmon resonance to investigate the thermodynamic and kinetic processes during hydrogen-bonded interpolymer complexation. Varied polymers that are commonly used in layer-by-layer coatings and pharmaceutical preparations were selected to span a range of chemical functionalities including some known IPCs previously characterized by other techniques, and other polymer combinations with unknown outcomes. This work is the first to comprehensively detail the thermodynamic and kinetic data of hydrogen bonded IPCs, aiding understanding and detailed characterization of the complexes. The applicability of the two techniques in determining thermodynamic, gravimetric and kinetic properties of IPCs is considered.

  12. Applications of Isothermal Titration Calorimetry in Biophysical Studies of G-quadruplexes

    Directory of Open Access Journals (Sweden)

    Concetta Giancola

    2009-07-01

    Full Text Available G-quadruplexes are higher-order nucleic acids structures formed by G-rich sequences that are stabilized by tetrads of hydrogen-bonded guanine bases. Recently, there has been growing interest in the study of G-quadruplexes because of their possible involvement in many biological processes. Isothermal titration calorimetry (ITC has been proven to be a useful tool to study the energetic aspects of G-quadruplex interactions. Particularly, ITC has been applied many times to determine the thermodynamic properties of drug-quadruplex interactions to screening among various drugs and to address drug design. In the present review, we will focus on the ITC studies of G-quadruplex structures and their interaction with proteins and drugs and the most significant results will be discussed.

  13. Integration and global analysis of isothermal titration calorimetry data for studying macromolecular interactions.

    Science.gov (United States)

    Brautigam, Chad A; Zhao, Huaying; Vargas, Carolyn; Keller, Sandro; Schuck, Peter

    2016-05-01

    Isothermal titration calorimetry (ITC) is a powerful and widely used method to measure the energetics of macromolecular interactions by recording a thermogram of differential heating power during a titration. However, traditional ITC analysis is limited by stochastic thermogram noise and by the limited information content of a single titration experiment. Here we present a protocol for bias-free thermogram integration based on automated shape analysis of the injection peaks, followed by combination of isotherms from different calorimetric titration experiments into a global analysis, statistical analysis of binding parameters and graphical presentation of the results. This is performed using the integrated public-domain software packages NITPIC, SEDPHAT and GUSSI. The recently developed low-noise thermogram integration approach and global analysis allow for more precise parameter estimates and more reliable quantification of multisite and multicomponent cooperative and competitive interactions. Titration experiments typically take 1-2.5 h each, and global analysis usually takes 10-20 min.

  14. DETERMINATION OF HYDROGEN DESORBED THROUGH THERMAL CALORIMETRY IN A HIGH STRENGTH STEEL

    Directory of Open Access Journals (Sweden)

    Carolina A. Asmus

    2014-03-01

    Full Text Available The following study aims to quantify the release activation energy (Ea of hydrogen (H from lattice sites, reversible or irreversible, where the H can be trapped. Moreover, enthalpy changes associated with the main hydrogen (H trapping sites can be analyzed by means of differential scanning calorimetry (DSC. In this technique, the peak temperature measurement is determined at two different heating rates, 3ºC/min y 5ºC/min, from ambient temperature to 500°C. In order to simulate severe conditions of hydrogen income into resulfurized high strength steel, electrolytic permeation tests were performed on test tubes suitable for fatigue tests. Sometimes during charging, H promoters were aggregated to electrolytic solution. Subsequently, the test tubes were subjected to flow cycle fatigue tests. Finally, irreversible trap which anchor more strongly H atoms are MnS inclusions. Its role on hydrogen embrittlement during fatigue tests is conclusive.

  15. Research and Development for the ATLAS Forward Calorimetry at the HL-LHC

    CERN Document Server

    Cheplakov, Alexander

    2015-01-01

    A total luminosity of 3000/fb is expected at the HL-LHC, which corresponds to total irradiation doses which are more than doubled compared to the original design, taking into account a safety factor of 2 representing our confidence in radiation background simulations. Moreover, the increased instantaneous luminosity will result in a much higher detector occupancy. The ATLAS Forward Calorimeters (FCal) will be affected by these factors. A rich R&D program is ongoing to evaluate the consequences of the LHC modernization and to investigate di_erent scenarios proposed for the Phase-II detector upgrade. This contribution will concentrate on simulation studies of the FCal degradation and on irradiation tests performed at the IBR-2m reactor in Dubna. Results from radiation-tolerant sensors and components of the future read-out and voltage distribution system for various upgrade options of the forward calorimetry will be presented.

  16. FLUKA studies of hadron-irradiated scintillating crystals for calorimetry at the High-Luminosity LHC

    CERN Document Server

    Quittnat, Milena Eleonore

    2015-01-01

    Calorimetry at the High-Luminosity LHC (HL-LHC) will be performed in a harsh radiation environment with high hadron fluences. The upgraded CMS electromagnetic calorimeter design and suitable scintillating materials are a focus of current research. In this paper, first results using the Monte Carlo simulation program FLUKA are compared to measurements performed with proton-irradiated LYSO, YSO and cerium fluoride crystals. Based on these results, an extrapolation to the behavior of an electromagnetic sampling calorimeter, using one of the inorganic scintillators above as an active medium, is performed for the upgraded CMS experiment at the HL-LHC. Characteristic parameters such as the induced ambient dose, fluence spectra for different particle types and the residual nuclei are studied, and the suitability of these materials for a future calorimeter is surveyed. Particular attention is given to the creation of isotopes in an LYSO-tungsten calorimeter that might contribute a prohibitive background to the measu...

  17. Thermophysical analysis of II-VI semiconductors by PPE calorimetry and lock-in thermography

    Energy Technology Data Exchange (ETDEWEB)

    Streza, M.; Dadarlat, D. [National Institute for Research and Development of Isotopic and Molecular Technologies, 65-103 Donath, 400293 Cluj-Napoca (Romania); Strzałkowski, K. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 (Poland)

    2013-11-13

    An accurate determination of thermophysical properties such as thermal diffusivity, thermal effusivity and thermal conductivity is extremely important for characterization and quality assurance of semiconductors. Thermal diffusivity and effusivity of some binary semiconductors have been investigated. Two experimental techniques were used: a contact technique (PPE calorimetry) and a non contact technique (lock-in thermography). When working with PPE, in the back (BPPE) configuration and in the thermally thick regim of the pyroelectric sensor, we can get the thermal diffusivity of the sample by performing a scanning of the excitation frequency of radiation. Thermal effusivity is obtained in front configuration (sensor directly irradiated and sample in back position) by performing a thickness scan of a coupling fluid. By using the lock-in thermography technique, the thermal diffusivity of the sample is obtained from the phase image. The results obtained by the two techniques are in good agreement. Nevertheless, for the determination of thermal diffusivity, lock-in thermography is preferred.

  18. Impact of sample saturation on the detected porosity of hardened concrete using low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn

    2014-01-01

    The present work studied the impact of sample saturation on the analysis of pore volume and pore size distribution by low temperature (micro-)calorimetry. The theoretical background was examined, which emphasizes that the freezing/melting temperature of water/ice confined in non-fully saturated...... samples and a higher proportion of pores with small radii were found in the capillary saturated samples. In addition, the observed hysteresis between the freezing and melting curves of ice content of the capillary saturated samples was more pronounced than that of the vacuum saturated samples. The major...... pores is further depressed compared with that when the pores are fully saturated. The study of the experimental data on hardened concrete samples showed that for a same concrete mix, the total pore volume detected from the capillary saturated samples was always lower than that of the vacuum saturated...

  19. Ln(III)-malate complexation studies using TRLFS and micro titration calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Taube, F.; Drobot, B. [Technische Univ. Dresden (Germany). Professorship Radiochemistry; Acker, M.; Taut, S. [Technische Univ. Dresden (Germany). Central Radionuclide Laboratory; Stumpf, Thorsten [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Inst. of Resource Ecology

    2017-06-01

    The complexation of trivalent lanthanides was studied using Time-Resolved Laser-Induced Fluorescence Spectroscopy (TRLFS) and Isothermal Titration Calorimetry (ITC). Formation constants, complexation enthalpies and fluorescence lifetimes are determined over a wide pH range at I = 0.5 m NaCl. This subject has the following background: Concrete is widely used as engineering barrier and for waste conditioning in waste repositories. Its binding agent is cement. Organic cement additives, which are used to improve the workability of fresh concrete, are complexation agents for radionuclides after they have been released during the concretes degradation. Thus, these additives might have an impact on the aqueous geochemistry of actinides. Here, the α-hydroxydicarboxylic acid or malic acid is examined. It is used in water-reducers or retarders in cement.

  20. From calorimetry to medical imaging: a shining example of successful transfer!

    CERN Multimedia

    Caroline Duc

    2012-01-01

    A team at CERN has drawn inspiration from calorimetry methods developed for high-energy physics to create a new positron-emission tomography system for use in medical imaging, which they’ve dubbed AX-PET. With support from European and American laboratories*, the project is reaching fruition, as initial tests confirm its promise.   Snapshot of a “phantom”, a test object, surrounded by the AX-PET photon detectors. Positron-emission tomography (PET) is a medical imaging technique based on the matter-antimatter interaction that can provide a three-dimensional representation of the metabolic activity of an organ. To do so, radioactive marker molecules are first injected into the subject. As the marker decays, it emits positrons (antimatter particles), which are annihilated upon encountering electrons in the surrounding environment. The resulting flash, consisting of two photons, is detected by the PET machine. In conventional PET systems, it is impossible to improv...

  1. Fluence correction factor for graphite calorimetry in a clinical high-energy carbon-ion beam

    Science.gov (United States)

    Lourenço, A.; Thomas, R.; Homer, M.; Bouchard, H.; Rossomme, S.; Renaud, J.; Kanai, T.; Royle, G.; Palmans, H.

    2017-04-01

    The aim of this work is to develop and adapt a formalism to determine absorbed dose to water from graphite calorimetry measurements in carbon-ion beams. Fluence correction factors, {{k}\\text{fl}} , needed when using a graphite calorimeter to derive dose to water, were determined in a clinical high-energy carbon-ion beam. Measurements were performed in a 290 MeV/n carbon-ion beam with a field size of 11  ×  11 cm2, without modulation. In order to sample the beam, a plane-parallel Roos ionization chamber was chosen for its small collecting volume in comparison with the field size. Experimental information on fluence corrections was obtained from depth-dose measurements in water. This procedure was repeated with graphite plates in front of the water phantom. Fluence corrections were also obtained with Monte Carlo simulations through the implementation of three methods based on (i) the fluence distributions differential in energy, (ii) a ratio of calculated doses in water and graphite at equivalent depths and (iii) simulations of the experimental setup. The {{k}\\text{fl}} term increased in depth from 1.00 at the entrance toward 1.02 at a depth near the Bragg peak, and the average difference between experimental and numerical simulations was about 0.13%. Compared to proton beams, there was no reduction of the {{k}\\text{fl}} due to alpha particles because the secondary particle spectrum is dominated by projectile fragmentation. By developing a practical dose conversion technique, this work contributes to improving the determination of absolute dose to water from graphite calorimetry in carbon-ion beams.

  2. Irreversible denaturation of maltodextrin glucosidase studied by differential scanning calorimetry, circular dichroism, and turbidity measurements.

    Science.gov (United States)

    Goyal, Megha; Chaudhuri, Tapan K; Kuwajima, Kunihiro

    2014-01-01

    Thermal denaturation of Escherichia coli maltodextrin glucosidase was studied by differential scanning calorimetry, circular dichroism (230 nm), and UV-absorption measurements (340 nm), which were respectively used to monitor heat absorption, conformational unfolding, and the production of solution turbidity. The denaturation was irreversible, and the thermal transition recorded at scan rates of 0.5-1.5 K/min was significantly scan-rate dependent, indicating that the thermal denaturation was kinetically controlled. The absence of a protein-concentration effect on the thermal transition indicated that the denaturation was rate-limited by a mono-molecular process. From the analysis of the calorimetric thermograms, a one-step irreversible model well represented the thermal denaturation of the protein. The calorimetrically observed thermal transitions showed excellent coincidence with the turbidity transitions monitored by UV-absorption as well as with the unfolding transitions monitored by circular dichroism. The thermal denaturation of the protein was thus rate-limited by conformational unfolding, which was followed by a rapid irreversible formation of aggregates that produced the solution turbidity. It is thus important to note that the absence of the protein-concentration effect on the irreversible thermal denaturation does not necessarily means the absence of protein aggregation itself. The turbidity measurements together with differential scanning calorimetry in the irreversible thermal denaturation of the protein provided a very effective approach for understanding the mechanisms of the irreversible denaturation. The Arrhenius-equation parameters obtained from analysis of the thermal denaturation were compared with those of other proteins that have been reported to show the one-step irreversible thermal denaturation. Maltodextrin glucosidase had sufficiently high kinetic stability with a half-life of 68 days at a physiological temperature (37°C).

  3. Differential binding models for isothermal titration calorimetry: moving beyond the Wiseman isotherm.

    Science.gov (United States)

    Herrera, Isaac; Winnik, Mitchell A

    2013-07-25

    We present a set of model-independent differential equations to analyze isothermal titration calorimetry (ITC) experiments. In contrast with previous approaches that begin with specific assumptions about the number of binding sites and the interactions among them (e.g., sequential, independent, cooperative), our derivation makes more general assumptions, such that a receptor with multiple sites for one type of ligand species (homotropic binding) can be studied with the same analytical expression. Our approach is based on the binding polynomial formalism, and the resulting analytical expressions can be extended to account for any number of binding sites and any type of binding interaction among them. We refer to the set of model-independent differential equations to study ITC experiments as a differential binding model (DBM). To demonstrate the flexibility of our DBM, we present the analytical expressions to study receptors with one or two binding sites. The DBM for a receptor with one site is equivalent to the Wiseman isotherm but with a more intuitive representation that depends on the binding polynomial and the dimensionless parameter c = K·MT, where K is the binding constant and MT the total receptor concentration. In addition, we show how to constrain the general DBM for a receptor with two sites to represent sequential, independent, or cooperative binding interactions between the sites. We use the sequential binding model to study the binding interaction between Gd(III) and citrate anions. In addition, we simulate calorimetry titrations of receptors with positive, negative, and noncooperative interactions between the two binding sites. Finally, we derive a DBM for titrations of receptors with n-independent binding sites.

  4. Efficient Isothermal Titration Calorimetry Technique Identifies Direct Interaction of Small Molecule Inhibitors with the Target Protein.

    Science.gov (United States)

    Gal, Maayan; Bloch, Itai; Shechter, Nelia; Romanenko, Olga; Shir, Ofer M

    2016-01-01

    Protein-protein interactions (PPI) play a critical role in regulating many cellular processes. Finding novel PPI inhibitors that interfere with specific binding of two proteins is considered a great challenge, mainly due to the complexity involved in characterizing multi-molecular systems and limited understanding of the physical principles governing PPIs. Here we show that the combination of virtual screening techniques, which are capable of filtering a large library of potential small molecule inhibitors, and a unique secondary screening by isothermal titration calorimetry, a label-free method capable of observing direct interactions, is an efficient tool for finding such an inhibitor. In this study we applied this strategy in a search for a small molecule capable of interfering with the interaction of the tumor-suppressor p53 and the E3-ligase MDM2. We virtually screened a library of 15 million small molecules that were filtered to a final set of 80 virtual hits. Our in vitro experimental assay, designed to validate the activity of mixtures of compounds by isothermal titration calorimetry, was used to identify an active molecule against MDM2. At the end of the process the small molecule (4S,7R)-4-(4-chlorophenyl)-5-hydroxy-2,7-dimethyl-N-(6-methylpyridin-2-yl)-4,6,7,8 tetrahydrIoquinoline-3-carboxamide was found to bind MDM2 with a dissociation constant of ~2 µM. Following the identification of this single bioactive compound, spectroscopic measurements were used to further characterize the interaction of the small molecule with the target protein. 2D NMR spectroscopy was used to map the binding region of the small molecule, and fluorescence polarization measurement confirmed that it indeed competes with p53.

  5. Comparison of a Handheld Indirect Calorimetry Device and Predictive Energy Equations Among Individuals on Maintenance Hemodialysis.

    Science.gov (United States)

    Morrow, Ellis A; Marcus, Andrea; Byham-Gray, Laura

    2017-11-01

    Practical methods for determining resting energy expenditure (REE) among individuals on maintenance hemodialysis (MHD) are needed because of the limitations of indirect calorimetry. Two disease-specific predictive energy equations (PEEs) have been developed for this metabolically complex population. The aim of this study was to compare estimated REE (eREE) by PEEs to measured REE (mREE) with a handheld indirect calorimetry device (HICD). A prospective pilot study of adults on MHD (N = 40) was conducted at 2 dialysis clinics in Houston and Texas City, Texas. mREE by an HICD was compared with eREE determined by 6 PEEs using Bland-Altman analysis with a band of acceptable agreement of ±10% of the group mean mREE. Paired t-test and the intraclass correlation coefficient were also used to compare the alternate methods of measuring REE. A priori alpha was set at P Maintenance Hemodialysis Equation-Creatinine version (MHCD-CR) was the most accurate PEE with 52.5% of values within the band of acceptable agreement, followed by the Mifflin-St. Jeor Equation and the Vilar et al. Equation at 45.0% and 42.5%, respectively. When compared with mREE by the HICD, the MHDE-CR was more accurate and precise than other PEEs evaluated; however, this must be interpreted with caution as mREE was consistently lower than eREE from all PEEs. Further research is needed to validate the MHDE-CR and other practical methods for determining REE among individuals on MHD. Copyright © 2017 National Kidney Foundation, Inc. Published by Elsevier Inc. All rights reserved.

  6. Fluence correction factor for graphite calorimetry in a clinical high-energy carbon-ion beam.

    Science.gov (United States)

    Lourenço, A; Thomas, R; Homer, M; Bouchard, H; Rossomme, S; Renaud, J; Kanai, T; Royle, G; Palmans, H

    2017-04-07

    The aim of this work is to develop and adapt a formalism to determine absorbed dose to water from graphite calorimetry measurements in carbon-ion beams. Fluence correction factors, [Formula: see text], needed when using a graphite calorimeter to derive dose to water, were determined in a clinical high-energy carbon-ion beam. Measurements were performed in a 290 MeV/n carbon-ion beam with a field size of 11  ×  11 cm(2), without modulation. In order to sample the beam, a plane-parallel Roos ionization chamber was chosen for its small collecting volume in comparison with the field size. Experimental information on fluence corrections was obtained from depth-dose measurements in water. This procedure was repeated with graphite plates in front of the water phantom. Fluence corrections were also obtained with Monte Carlo simulations through the implementation of three methods based on (i) the fluence distributions differential in energy, (ii) a ratio of calculated doses in water and graphite at equivalent depths and (iii) simulations of the experimental setup. The [Formula: see text] term increased in depth from 1.00 at the entrance toward 1.02 at a depth near the Bragg peak, and the average difference between experimental and numerical simulations was about 0.13%. Compared to proton beams, there was no reduction of the [Formula: see text] due to alpha particles because the secondary particle spectrum is dominated by projectile fragmentation. By developing a practical dose conversion technique, this work contributes to improving the determination of absolute dose to water from graphite calorimetry in carbon-ion beams.

  7. Interaction between dry starch and plasticisers glycerol or ethylene glycol, measured by differential scanning calorimetry and solid state NMR spectroscopy

    NARCIS (Netherlands)

    Smits, A.L.M.; Kruiskamp, P.H.; Soest, van J.J.G.; Vliegenthart, J.F.G.

    2003-01-01

    The interaction of crystalline amylose and of crystalline and amorphous amylopectin with the plasticisers glycerol or ethylene glycol in the absence of water was studied, by using differential scanning calorimetry (DSC) and solid state nuclear magnetic resonance (NMR) spectroscopy. Upon heating

  8. Determination of thermodynamic potentials and the aggregation number for micelles with the mass-action model by isothermal titration calorimetry

    DEFF Research Database (Denmark)

    Olesen, Niels Erik; Westh, Peter; Holm, René

    2015-01-01

    The aggregation number (n), thermodynamic potentials (ΔG, ΔH, ΔS) and critical micelle concentration (CMC) for 6 natural bile salts were determined on the basis of both original and previously published isothermal titration calorimetry (ITC) data. Different procedures to estimate parameters...

  9. Kinetic properties of two Rhizopus exo-polygalacturonase enzymes hydrolyzing galacturonic acid oligomers using isothermal titration calorimetry

    Science.gov (United States)

    The kinetic characteristics of two Rhizopus oryzae exo-polygalacturonases acting on galacturonic acid oligomers (GalpA) were determined using isothermal titration calorimetry (ITC). RPG15 hydrolyzing (GalpA)2 demonstrated a Km of 55 uM and kcat of 10.3 s^-1^ while RPG16 was shown to have greater af...

  10. Studies on sampling and homogeneous dual readout calorimetry with meta-crystals

    CERN Document Server

    Mavromanolakis, G; Lecoq, P

    2011-01-01

    The meta-crystals concept is an approach that consists of using both undoped and properly doped heavy crystal fibers of identical material as the active medium of a calorimeter. The undoped fibers behave as Cherenkov radiators while the doped ones behave as scintillators. A dual readout calorimeter can be built with its sensitive volume composed of a mixture of both types of crystals. In addition if the calorimeter is adequately finely segmented it can also function as a particle flow calorimeter at the same time. In this way one could possibly combine the advantages of both the particle flow concept and the dual readout scheme. We discuss the approach of dual readout calorimetry with meta-crystals made of Lutetium Aluminium Garnet (LuAG). We brie fly present studies on the material development and first testbeam activities and then focus on performance expectation studies based on simulation. We discuss in more detail the results from generic systematic scannings of the design parameters of a dual readout ca...

  11. Misuse of thermodynamics in the interpretation of isothermal titration calorimetry data for ligand binding to proteins.

    Science.gov (United States)

    Pethica, Brian A

    2015-03-01

    Isothermal titration calorimetry (ITC) has given a mass of data on the binding of small molecules to proteins and other biopolymers, with particular interest in drug binding to proteins chosen as therapeutic indicators. Interpretation of the enthalpy data usually follows an unsound protocol that uses thermodynamic relations in circumstances where they do not apply. Errors of interpretation include incomplete definitions of ligand binding and equilibrium constants and neglect of the non-ideality of the solutions under study, leading to unreliable estimates of standard free energies and entropies of binding. The mass of reported thermodynamic functions for ligand binding to proteins estimated from ITC enthalpies alone is consequently of uncertain thermodynamic significance and utility. ITC and related experiments to test the protocol assumptions are indicated. A thermodynamic procedure avoiding equilibrium constants or other reaction models and not requiring protein activities is given. The discussion draws attention to the fundamental but neglected relation between the thermodynamic activity and bioactivity of drugs and to the generally unknown thermodynamic status of ligand solutions, which for drugs relates directly to effective therapeutic dosimetry. Copyright © 2014 Elsevier Inc. All rights reserved.

  12. PHARMACEUTICAL AMORPHOUS ORGANIC MATERIALS CHARACTERIZATION BY USING THE DIFFERENTIAL SCANNING CALORIMETRY AND DYNAMIC MECHANICAL ANALYSIS

    Directory of Open Access Journals (Sweden)

    Ion Dranca

    2011-12-01

    Full Text Available This research has been carried out in order to demonstrate the use of differential scanning calorimetry (DSC in detecting and measuring α- and β-relaxation processes in amorphous pharmaceutical systems. DSC has been employed to study amorphous samples of poly (vinylpyrrolidone (PVP, indomethacin (InM, and ursodeoxycholic acid (UDA that are annealed at temperature (Ta around 0.8 of their glass transition temperature (Tg. Dynamic mechanical analysis (DMA is used to measure β- relaxation in PVP. Yet, the DSC has been used to study the glassy indomethacin aged at 0 and -10 oC for periods of time up to 109 and 210 days respectively. The results demonstrate the emergence of a small melting peak of the α-polymorph after aging for 69 days at 0°C and for 147 days at -10°C (i.e., ~55°C below the glass transition temperature that provides evidence of nucleation occurring in the temperature region of the β-relaxation.

  13. Building a Graphite Calorimetry System for the Dosimetry of Therapeutic X-ray Beams

    Directory of Open Access Journals (Sweden)

    In Jung Kim

    2017-06-01

    Full Text Available A graphite calorimetry system was built and tested under irradiation. The noise level of the temperature measurement system was approximately 0.08 mK (peak to peak. The temperature of the core part rose by approximately 8.6 mK at 800 MU (monitor unit for 6-MV X-ray beams, and it increased as X-ray energy increased. The temperature rise showed less spread when it was normalized to the accumulated charge, as measured by an external monitoring chamber. The radiation energy absorbed by the core part was determined to have values of 0.798 J/μC, 0.389 J/μC, and 0.352 J/μC at 6 MV, 10 MV, and 18 MV, respectively. These values were so consistent among repeated runs that their coefficient of variance was less than 0.15%.

  14. Calorimetry Minisensor for the Localised Measurement of Surface Heat Dissipated from the Human Body.

    Science.gov (United States)

    Socorro, Fabiola; Rodríguez de Rivera, Pedro Jesús; Rodríguez de Rivera, Manuel

    2016-11-06

    We have developed a calorimetry sensor that can perform a local measurement of the surface heat dissipated from the human body. The operating principle is based on the law of conductive heat transfer: heat dissipated by the human body passes across a thermopile located between the individual and a thermostat. Body heat power is calculated from the signals measured by the thermopile and the amount of power dissipated across the thermostat in order to maintain a constant temperature. The first prototype we built had a detection area measuring 6 × 6 cm², while the second prototype, which is described herein, had a 2 × 2 cm² detection area. This new design offers three advantages over the initial one: (1) greater resolution and three times greater thermal sensitivity; (2) a twice as fast response; and (3) it can take measurements from smaller areas of the body. The sensor has a 5 mW resolution, but the uncertainty is greater, up to 15 mW, due to the measurement and calculation procedure. The order of magnitude of measurements made in healthy subjects ranged from 60 to 300 mW at a thermostat temperature of 28 °C and an ambient room temperature of 21 °C. The values measured by the sensor depend on the ambient temperature and the thermostat's temperature, while the power dissipated depends on the individual's metabolism and any physical and/or emotional activity.

  15. Beam Studies of the Segmented Resistive WELL: a Potential Thin Sampling Element for Digital Hadron Calorimetry

    CERN Document Server

    Arazi, Lior; Breskin, Amos; Bressler, Shikma; Moleri, Luca; Natal da Luz, Hugo; Oliveri, Eraldo; Pitt, Michael; Rubin, Adam; Marques Ferreira dos Santos, Joaquim; Calapez Albuquerque Veloso, João Filipe; White, Andrew Paul

    2013-01-01

    Thick Gas Electron Multipliers (THGEMs) have the potential of constituting thin, robust sampling elements in Digital Hadron Calorimetry (DHCAL) in future colliders. We report on recent beam studies of new single- and double-THGEM-like structures; the multiplier is a Segmented Resistive WELL (SRWELL) - a single-faced THGEM in contact with a segmented resistive layer inductively coupled to readout pads. Several 10$\\times$10 cm$^2$ configurations with a total thickness of 5-6 mm (excluding electronics) with 1 cm$^2$ pads coupled to APV-SRS readout were investigated with muons and pions. Detection efficiencies in the 98$%$ range were recorded with average pad-multiplicity of $\\sim$1.1. The resistive anode resulted in efficient discharge damping, with potential drops of a few volts; discharge probabilities were $\\sim10^{-7}$ for muons and $\\sim10^{-6}$ for pions in the double-stage configuration, at rates of a few kHz/cm$^2$. Further optimization work and research on larger detectors are underway.

  16. Preventing Underfeeding and Overfeeding: A Clinician's Guide to the Acquisition and Implementation of Indirect Calorimetry.

    Science.gov (United States)

    Ladd, Amy K; Skillman, Heather E; Haemer, Matthew A; Mourani, Peter M

    2017-05-01

    In critically ill patients, indirect calorimetry (IC) is the gold standard to determine energy needs, as the use of predictive equations can result in underfeeding or overfeeding. The aim of this quality improvement (QI) initiative was to describe the rationale for and implementation of a process to target energy provision according to IC measurements in a tertiary academic medical center pediatric intensive care unit (PICU). To justify the purchase of an indirect calorimeter for clinical use, a needs assessment was conducted, followed by a training and implementation period. PICU patients were selected for IC according to published guidelines. Measured energy expenditure was compared with predicted energy expenditure and the provided energy prescription. The dietitians assessed IC results and adjusted energy prescriptions, if indicated. Thirty-five total tests were completed with 24 patients. Sixty-nine percent of measurements resulted in energy delivery adjustments. Fifteen (47%) energy prescriptions decreased by a mean of 27% ± 11%, and 7 (22%) increased by a mean of 17% ± 15%. Staff and patient/guardians accommodated the use of IC, and PICU dietitian recommendations for IC tests and to adjust nutrition regimens were universally implemented. Data to support the procurement of IC are vital to promote best practice to measure energy expenditure. Critically ill pediatric patients exhibit metabolic alterations that cannot be predicted by standard equations. Our QI initiative demonstrated the implementation and application of IC in the critically ill population and the ability to target energy provision to prevent energy imbalances.

  17. Morphological Investigation into Starch Bio-Nanocomposites via Synchrotron Radiation and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Huihua Liu

    2011-01-01

    Full Text Available We studied a hydrophilic, plasticized bionanocomposite system involving sorbitol plasticizer, amylose biopolymer, and montmorillonite (MMT for the presence of competitive interactions among them at different moisture content. Synchrotron analysis via small angle X-ray scattering (SAXS and thermal analysis using differential scanning calorimetry (DSC were performed to understand crystalline growth and the distribution of crystalline domains within the samples. The SAXS diffraction patterns showed reduced interhelix spacing in the amylose network indicating strong amylose-sorbitol interactions. Depending on the sorbitol and MMT concentration, these interactions also affected the free moisture content and crystalline domains. Domains of around 95 Å and 312 Å were found in the low-moisture-content samples as compared to a single domain of 95 Å in the high-moisture-content samples. DSC measurements confirmed that the MMT increased the onset and the melting temperature of nanocomposites. Moreover, the results showed that the ternary interactions among sorbitol-amylose-MMT supported the crystalline heterogeneity through secondary nucleation.

  18. Estimating relative physical workload using heart rate monitoring: a validation by whole-body indirect calorimetry.

    Science.gov (United States)

    Garet, Martin; Boudet, Gil; Montaurier, Christophe; Vermorel, Michel; Coudert, Jean; Chamoux, Alain

    2005-05-01

    Measuring physical workload in occupational medicine is fundamental for risk prevention. An indirect measurement of total and relative energy expenditure (EE) from heart rate (HR) is widely used but it has never been validated. The aim of this study was to validate this HR-estimated energy expenditure (HREEE) method against whole-body indirect calorimetry. Twenty-four-hour HR and EE values were recorded continuously in a calorimetric chambers for 52 adult males and females (19-65 years). An 8-h working period was retained, comprising several exercise sessions on a cycloergometer at intensities up to 65% of the peak rate of oxygen uptake. HREEE was calculated with reference to cardiac reserve. A corrected HREEE (CHREEE) was also calculated with a modification to the lowest value of cardiac reserve. Both values were further compared to established methods: the flex-HR method, and the use of a 3rd order polynomial relationship to estimate total and relative EE. No significant difference was found in total EE when measured in a calorimetric chamber or estimated from CHREEE for the working period. A perfect linear and identity relationship was found between CHREEE and energy reserve values for intensities ranging from 15% to 65%. Relative physical workload can be accurately assessed from HR recordings when expressed in CHREEE between 15% to 65%, and EE can be accurately estimated using the CHREEE method.

  19. High throughput integrated thermal characterization with non-contact optical calorimetry

    Science.gov (United States)

    Hou, Sichao; Huo, Ruiqing; Su, Ming

    2017-10-01

    Commonly used thermal analysis tools such as calorimeter and thermal conductivity meter are separated instruments and limited by low throughput, where only one sample is examined each time. This work reports an infrared based optical calorimetry with its theoretical foundation, which is able to provide an integrated solution to characterize thermal properties of materials with high throughput. By taking time domain temperature information of spatially distributed samples, this method allows a single device (infrared camera) to determine the thermal properties of both phase change systems (melting temperature and latent heat of fusion) and non-phase change systems (thermal conductivity and heat capacity). This method further allows these thermal properties of multiple samples to be determined rapidly, remotely, and simultaneously. In this proof-of-concept experiment, the thermal properties of a panel of 16 samples including melting temperatures, latent heats of fusion, heat capacities, and thermal conductivities have been determined in 2 min with high accuracy. Given the high thermal, spatial, and temporal resolutions of the advanced infrared camera, this method has the potential to revolutionize the thermal characterization of materials by providing an integrated solution with high throughput, high sensitivity, and short analysis time.

  20. Advanced monolithic active pixel sensors for tracking, vertexing and calorimetry with full CMOS capability

    Science.gov (United States)

    Stanitzki, M.; SPiDeR Collaboration, www. spider. ac. uk

    2011-09-01

    We present test results from the "TPAC" and "F ORTIS" sensors produced using the 180 nm CMOS INMAPS process. The TPAC sensor has a 50 μm pixel size with advanced in-pixel electronics. Although TPAC was developed for digital electromagnetic calorimetry, the technology can be readily extended to tracking and vertexing applications where highly granular pixels with in-pixel intelligence are required. By way of example, a variant of the TPAC sensor has been proposed for the Super B vertex detector. The F ORTIS sensor is a prototype with several pixel variants to study the performance of a four transistors (4T) architecture and is the first sensor of this type tested for particle physics applications. TPAC and F ORTIS sensors have been fabricated with some of the processing innovations available in INMAPS such as deep p-wells and high-resistivity epitaxial layers. The performance of these sensor variants has been measured both in the laboratory and at test beams and results showing significant improvements due to these innovations are presented. We have recently manufactured the "C HERWELL" sensor, building on the experience with both TPAC and F ORTIS and making use of the 4T approach. C HERWELL is designed for tracking and vertexing and has an integrated ADC and targets very low-noise performance. The principal features of C HERWELL are described.

  1. Appropriateness of the definition of 'sedentary' in young children: Whole-room calorimetry study.

    Science.gov (United States)

    Reilly, John J; Janssen, Xanne; Cliff, Dylan P; Okely, Anthony D

    2015-09-01

    The present study aimed to measure the energy cost of three common sedentary activities in young children to test whether energy expended was consistent with the recent consensus definition of 'sedentary' as 'any behaviour conducted in a sitting or reclining posture and with an energy cost ≤ 1.5 metabolic equivalents (METs)' (Sedentary Behaviour Research Network, 2012). Observational study. Whole-room calorimetry measures of television viewing, sitting at a table drawing and reading, and sitting on the floor playing with toys were made in 40 young children (mean age 5.3 years, SD 1.0). The energy cost of each sedentary activity was consistent with the recent consensus definition of sedentary: 1.17 METs (95% CI 1.07-1.27) for TV viewing; 1.38 METs (95% CI 1.30-1.46) for sitting at a table; and 1.35 METs (95% CI 1.28-1.43) for floor-based play. Common sedentary activities in young children have energy costs which are consistent with the recent consensus definition of 'sedentary', and the present study is supportive of this definition. Copyright © 2014 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  2. DCal: A custom integrated circuit for calorimetry at the International Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Hoff, James R.; Mekkaoui, Abderrazek; Yarema, Ray; /Fermilab; Drake, Gary; Repond, Jose; /Argonne

    2005-10-01

    A research and development collaboration has been started with the goal of producing a prototype hadron calorimeter section for the purpose of proving the Particle Flow Algorithm concept for the International Linear Collider. Given the unique requirements of a Particle Flow Algorithm calorimeter, custom readout electronics must be developed to service these detectors. This paper introduces the DCal or Digital Calorimetry Chip, a custom integrated circuit developed in a 0.25um CMOS process specifically for this International Linear Collider project. The DCal is capable of handling 64 channels, producing a 1-bit Digital-to-Analog conversion of the input (i.e. hit/no hit). It maintains a 24-bit timestamp and is capable of operating either in an externally triggered mode or in a self-triggered mode. Moreover, it is capable of operating either with or without a pipeline delay. Finally, in order to permit the testing of different calorimeter technologies, its analog front end is capable of servicing Particle Flow Algorithm calorimeters made from either Resistive Plate Chambers or Gaseous Electron Multipliers.

  3. Application of differential scanning calorimetry to estimate quality and nutritional properties of food products.

    Science.gov (United States)

    Parniakov, Oleksii; Bals, Olivier; Barba, Francisco J; Mykhailyk, Viacheslav; Lebovka, Nikolai; Vorobiev, Eugene

    2016-05-31

    Over the past years, both food researchers and food industry have shown an increased interest in finding techniques that can estimate modifications in quality, nutritional, and thermophysical properties of food products during processing and/or storage. For instance, differential scanning calorimetry (DSC) has attracted the interest of scientific community because only a small amount of sample is needed for analysis. Moreover, it does not require any specific sample preparation, and is a repeatable and reliable method. In addition, DSC methodology needs a short time for experiments compared with other techniques used for the same purpose. At this stage of investigation, there is a need to evaluate the commonly accepted and new emerging DSC applications to establish the optimum conditions of emerging processing. This paper reviews the current and new insights of DSC technique for the estimation of quality, nutritional, and thermophysical properties of food products during conventional and emerging processing and/or subsequent storage. The estimation of different properties in several food matrices after processing and/or storage is also discussed.

  4. Determination of calorific values of forest waste biomass by static bomb calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Nunez-Regueira, L.; Rodriguez-Anon, J.A.; Proupin-Castineiras, J.; Vilanova-Diz, A.; Montero-Santovena, N. [Department of Applied Physics, Research Group TERBIPROMAT, University of Santiago, 15706 Santiago (Spain)

    2001-04-26

    Calorific values of forest waste originating from forestry works such as woodland cleaning, reaforestation and, all other silviculture tasks, were measured by static bomb calorimetry. These waste materials, heretofore considered as useless refuse, are beginning to be used as alternative fuels in wide social sectors all over the world. Two of the main forest species, eucalyptus (E. globulus Labill) and pine (P. pinaster Aiton) existing in Galicia (NW Spain), are included in this study. The experimental procedure was based on that proposed by Hubbard et al. [Experimental Thermochemistry, Interscience, New York, 1956, p. 5]. Simultaneously, some other parameters such as elementary chemical composition and heavy metal contents, moisture, density, and ash percentage after combustion in the bomb, were also determined. The experimental results, with calorific values exceeding 20000kJkg{sup -1}, make it advisable to use these materials as alternative fuels. The different parameters were measured using, as main equipment, a bomb calorimeter with an oxygen atmosphere, an elementary analysis equipment, and an atomic absorption spectrophotometer.

  5. Sub-picowatt resolution calorimetry with niobium nitride thin-film thermometer.

    Science.gov (United States)

    Dechaumphai, Edward; Chen, Renkun

    2014-09-01

    High-resolution calorimetry has many important applications such as probing nanoscale thermal transport and studying the thermodynamics of biological and chemical systems. In this work, we demonstrated a calorimeter with an unprecedentedly high resolution at room temperature using a high-performance resistive thermometry material, niobium nitride (NbN(x)). Based on a theoretical analysis, we first showed that the heat flux resolution of a resistive-thermometry based calorimeter depends on the parasitic thermal conductance of the device and the temperature coefficient of resistance (TCR) of the thermometer, when the noise is limited by the Johnson noise. Based on this analysis, we then developed a calorimeter using NbNx as the thermometry material because it possesses both high TCR (~0.67%/K) and a low thermal conductivity (k ~ 1.1 W/m K). This calorimeter, when used with the modulated heating scheme, demonstrated an unprecedentedly high power resolution of 0.26 pW at room temperature. In addition, NbNx based resistive thermometry can also be extended to cryogenic temperature, where the TCR is shown to be significantly higher.

  6. Thermodynamic Study on the Protonation Reactions of Glyphosate in Aqueous Solution: Potentiometry, Calorimetry and NMR spectroscopy.

    Science.gov (United States)

    Liu, Bijun; Dong, Lan; Yu, Qianhong; Li, Xingliang; Wu, Fengchang; Tan, Zhaoyi; Luo, Shunzhong

    2016-03-10

    Glyphosate [N-(phosphonomethyl)glycine] has been described as the ideal herbicide because of its unique properties. There is some conflicting information concerning the structures and conformations involved in the protonation process of glyphosate. Protonation may influence the chemical and physical properties of glyphosate, modifying its structure and the chemical processes in which it is involved. To better understand the species in solution associated with changes in pH, thermodynamic study (potentiometry, calorimetry and NMR spectroscopy) about the protonation pathway of glyphosate is performed. Experimental results confirmed that the order of successive protonation sites of totally deprotonated glyphosate is phosphonate oxygen, amino nitrogen, and finally carboxylate oxygen. This trend is in agreement with the most recent theoretical work in the literature on the subject (J. Phys. Chem. A 2015, 119, 5241-5249). The result is important because it confirms that the protonated site of glyphosate in pH range 7-8, is not on the amino but on the phosphonate group instead. This corrected information can improve the understanding of the glyphosate chemical and biochemical action.

  7. Isothermal titration calorimetry uncovers substrate promiscuity of bicupin oxalate oxidase from Ceriporiopsis subvermispora.

    Science.gov (United States)

    Rana, Hassan; Moussatche, Patricia; Rocha, Lis Souza; Abdellaoui, Sofiene; Minteer, Shelley D; Moomaw, Ellen W

    2016-03-01

    Isothermal titration calorimetry (ITC) may be used to determine the kinetic parameters of enzyme-catalyzed reactions when neither products nor reactants are spectrophotometrically visible and when the reaction products are unknown. We report here the use of the multiple injection method of ITC to characterize the catalytic properties of oxalate oxidase (OxOx) from Ceriporiopsis subvermispora (CsOxOx), a manganese dependent enzyme that catalyzes the oxygen-dependent oxidation of oxalate to carbon dioxide in a reaction coupled with the formation of hydrogen peroxide. CsOxOx is the first bicupin enzyme identified that catalyzes this reaction. The multiple injection ITC method of measuring OxOx activity involves continuous, real-time detection of the amount of heat generated (dQ) during catalysis, which is equal to the number of moles of product produced times the enthalpy of the reaction (ΔHapp). Steady-state kinetic constants using oxalate as the substrate determined by multiple injection ITC are comparable to those obtained by a continuous spectrophotometric assay in which H2O2 production is coupled to the horseradish peroxidase-catalyzed oxidation of 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid) and by membrane inlet mass spectrometry. Additionally, we used multiple injection ITC to identify mesoxalate as a substrate for the CsOxOx-catalyzed reaction, with a kinetic parameters comparable to that of oxalate, and to identify a number of small molecule carboxylic acid compounds that also serve as substrates for the enzyme.

  8. Spectroscopy, calorimetry and molecular simulation studies on the interaction of catalase with copper ion.

    Science.gov (United States)

    Hao, Fang; Jing, Mingyang; Zhao, Xingchen; Liu, Rutao

    2015-02-01

    In this research, the binding mechanism of Cu(2+) to bovine liver catalase (BLC) was studied by fluorescence spectroscopy, ultraviolet-visible (UV-vis) absorption spectroscopy, circular dichroism (CD) spectroscopy, isothermal titration calorimetry (ITC) and molecular docking methods. The cellar experiment was firstly carried out to investigate the inhibition effect of catalase. During the fluorescence quenching study, after correcting the inner filter effect (IFE), the fluorescence of BLC was found to be quenched by Cu(2+). The quenching mechanism was determined by fluorescence lifetime measurement, and was confirmed to be the dynamic mode. The secondary structure content of BLC was changed by the addition of Cu(2+), as revealed by UV-vis absorption and CD spectra, which further induces the decrease in BLC activity. Molecular simulation study indicates that Cu(2+) is located between two β-sheets and two random coils of BLC near to the heme group, and interacts with His 74 and Ser 113 residues near a hydrophilic area. The decrease of α-helix and the binding of His 74 are considered to be the major reason for the inhibition of BLC activity caused by Cu(2+). The ITC results indicate that the binding stoichiometry of Cu(2+) to catalase is 11.4. Moreover, the binding of Cu(2+) to BLC destroyed H-bonds, which was confirmed by the CD result. Copyright © 2015 Elsevier B.V. All rights reserved.

  9. Isothermal titration calorimetry: experimental design, data analysis, and probing macromolecule/ligand binding and kinetic interactions.

    Science.gov (United States)

    Freyer, Matthew W; Lewis, Edwin A

    2008-01-01

    Isothermal titration calorimetry (ITC) is now routinely used to directly characterize the thermodynamics of biopolymer binding interactions and the kinetics of enzyme-catalyzed reactions. This is the result of improvements in ITC instrumentation and data analysis software. Modern ITC instruments make it possible to measure heat effects as small as 0.1 microcal (0.4 microJ), allowing the determination of binding constants, K's, as large as 10(8) - 10(9)M(-1). Modern ITC instruments make it possible to measure heat rates as small as 0.1 microcal/sec, allowing for the precise determination of reaction rates in the range of 10(-12) mol/sec. Values for K(m) and k(cat), in the ranges of 10(-2) - 10(3) microM and 0.05 - 500 sec(-1), respectively, can be determined by ITC. This chapter reviews the planning of an optimal ITC experiment for either a binding or kinetic study, guides the reader through simulated sample experiments, and reviews analysis of the data and the interpretation of the results.

  10. Application of Differential Scanning Calorimetry to Evaluate Thermal Properties and Study of Microstructure of Biodegradable Films

    Science.gov (United States)

    Aguilar-Méndez, M. A.; Martin-Martínez, E. San; Ortega-Arroyo, L.; Cruz-Orea, A.

    2010-03-01

    The glass transition temperature ( T g) and melting temperature ( T m) of gelatin-starch films were determined using differential scanning calorimetry. Also, the microstructure was observed using scanning electron microscopy (SEM) and the crystalline structure by means of X-ray diffraction (XRD). The effect of starch and glycerol concentrations in films on the thermal properties was evaluated through response surface methodology (RSM). The highest values of T m were obtained at starch concentration intervals of (0.26 to 0.54) %w/w and glycerol concentrations lower than 0.5 (%w/w). On the other hand, the T g values diminished as the glycerol concentration increased. Mathematical models for both transitions were fitted to the experimental data. The micrographs obtained by SEM show the influence of glycerol in the microstructure of the films, being more “gummy” as the content of the plasticizer increased. The XRD patterns of the films demonstrate the existence of some pseudo-crystalline regions in the biodegradable materials.

  11. Monitoring detergent-mediated solubilization and reconstitution of lipid membranes by isothermal titration calorimetry.

    Science.gov (United States)

    Heerklotz, Heiko; Tsamaloukas, Alekos D; Keller, Sandro

    2009-01-01

    The solubilization and reconstitution of biological or liposomal membranes by detergents and biomolecules with detergent-like properties play a major role for technical applications (e.g., the isolation of membrane proteins) and biological phenomena (of, e.g., amphiphilic peptides). It is therefore important to know and understand the amounts of a given detergent required for the onset and completion of membrane solubilization and the detergent-lipid interactions in general. Lipid-detergent systems can form a variety of aggregate structures, which can be grouped into two pseudophases (lamellae and micelles) so that solubilization can be approximately described as a phase transition. Here we present a protocol for establishing the phase diagram and a detailed thermodynamic description of a lipid-detergent system based on isothermal titration calorimetry (ITC). The protocol can also be used to detect additive-induced membrane destabilization, permeabilization, domain formation and lipid-dependent transitions between rod-like and spherical micelles. A minimal protocol consisting of all sample preparation procedures and a single solubilization experiment can be accomplished within 2 days; a more extensive series comprising both solubilization and reconstitution experiments requires several days to a few weeks, depending on the number of titrations performed.

  12. Application of isothermal titration calorimetry as a tool to study natural product interactions.

    Science.gov (United States)

    Callies, O; Hernández Daranas, A

    2016-07-28

    Covering: up to February 2015Over the past twenty-five years, isothermal titration calorimetry (ITC) has become a potent tool for the study a great variety of molecular interactions. This technique is able to provide a complete thermodynamic profile of an interaction process in a single experiment, with a series of advantages in comparison to other comparable techniques, such as less amount of sample or no need of chemical modification or labelling. It is thus not surprising that ITC has been applied to study the manifold types of interactions of natural products to get new insights into the molecular key factors implied in the complexation process of this type of compounds. This review provides an overview over the applications of ITC as a potent tool to investigate interactions of natural products with proteins, nucleic acids, oligosaccharides, and other types of receptors. The examples have been selected depending on the impact that this technique had during the investigation and revision of the interactions involved in the bioactivity of a compound, lead optimization or technical applications.

  13. Single-experiment displacement assay for quantifying high-affinity binding by isothermal titration calorimetry.

    Science.gov (United States)

    Krainer, Georg; Keller, Sandro

    2015-04-01

    Isothermal titration calorimetry (ITC) is the gold standard for dissecting the thermodynamics of a biomolecular binding process within a single experiment. However, reliable determination of the dissociation constant (KD) from a single titration is typically limited to the range 100 μM>KD>1 nM. Interactions characterized by a lower KD can be assessed indirectly by so-called competition or displacement assays, provided that a suitable competitive ligand is available whose KD falls within the directly accessible window. However, this protocol is limited by the fact that it necessitates at least two titrations to characterize one high-affinity inhibitor, resulting in considerable consumption of both sample material and time. Here, we introduce a fast and efficient ITC displacement assay that allows for the simultaneous characterization of both a high-affinity ligand and a moderate-affinity ligand competing for the same binding site on a receptor within a single experiment. The protocol is based on a titration of the high-affinity ligand into a solution containing the moderate-affinity ligand bound to the receptor present in excess. The resulting biphasic binding isotherm enables accurate and precise determination of KD values and binding enthalpies (ΔH) of both ligands. We discuss the theoretical background underlying the approach, demonstrate its practical application to metal ion chelation, explore its potential and limitations with the aid of simulations and statistical analyses, and elaborate on potential applications to protein-inhibitor interactions. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Microtubule-associated proteins and tubulin interaction by isothermal titration calorimetry.

    Science.gov (United States)

    Tsvetkov, P O; Barbier, P; Breuzard, G; Peyrot, V; Devred, F

    2013-01-01

    Microtubules play an important role in a number of vital cell processes such as cell division, intracellular transport, and cell architecture. The highly dynamic structure of microtubules is tightly regulated by a number of stabilizing and destabilizing microtubule-associated proteins (MAPs), such as tau and stathmin. Because of their importance, tubulin-MAPs interactions have been extensively studied using various methods that provide researchers with complementary but sometimes contradictory thermodynamic data. Isothermal titration calorimetry (ITC) is the only direct thermodynamic method that enables a full thermodynamic characterization (stoichiometry, enthalpy, entropy of binding, and association constant) of the interaction after a single titration experiment. This method has been recently applied to study tubulin-MAPs interactions in order to bring new insights into molecular mechanisms of tubulin regulation. In this chapter, we review the technical specificity of this method and then focus on the use of ITC in the investigation of tubulin-MAPs binding. We describe technical issues which could arise during planning and carrying out the ITC experiments, in particular with fragile proteins such as tubulin. Using examples of stathmin and tau, we demonstrate how ITC can be used to gain major insights into tubulin-MAP interaction. Copyright © 2013 Elsevier Inc. All rights reserved.

  15. Biomolecule-nanoparticle interactions: Elucidation of the thermodynamics by isothermal titration calorimetry.

    Science.gov (United States)

    Huang, Rixiang; Lau, Boris L T

    2016-05-01

    Nanomaterials (NMs) are often exposed to a broad range of biomolecules of different abundances. Biomolecule sorption driven by various interfacial forces determines the surface structure and composition of NMs, subsequently governs their functionality and the reactivity of the adsorbed biomolecules. Isothermal titration calorimetry (ITC) is a nondestructive technique that quantifies thermodynamic parameters through in-situ measurement of the heat absorption or release associated with an interaction. This review highlights the recent applications of ITC in understanding the thermodynamics of interactions between various nanoparticles (NPs) and biomolecules. Different aspects of a typical ITC experiment that are crucial for obtaining accurate and meaningful data, as well as the strengths, weaknesses, and challenges of ITC applications to NP research were discussed. ITC reveals the driving forces behind biomolecule-NP interactions and the effects of the physicochemical properties of both NPs and biomolecules by quantifying the crucial thermodynamics parameters (e.g., binding stoichiometry, ΔH, ΔS, and ΔG). Complimentary techniques would strengthen the interpretation of ITC results for a more holistic understanding of biomolecule-NP interactions. The thermodynamic information revealed by ITC and its complimentary characterizations is important for understanding biomolecule-NP interactions that are fundamental to the biomedical and environmental applications of NMs and their toxicological effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  16. In vivo characterization of thermal stabilities of Aeropyrum pernix cellular components by differential scanning calorimetry.

    Science.gov (United States)

    Milek, Igor; Crnigoj, Miha; Ulrih, Natasa Poklar; Kaletunç, Gönül

    2007-09-01

    Revival studies of Aeropyrum pernix show that the viability of cells and cell recovery after heat treatment depends on the temperature of treatment. Differential scanning calorimetry (DSC) is used to analyze the relative thermal stabilities of cellular components of A. pernix and to identify the cellular components responsible for the observed lag phase and reduced maximum growth following a heat treatment. DSC thermograms show 5 visible endothermic transitions with 2 major transitions. DSC analysis of isolated crude ribosomes aids the assignment of the 2 major peaks observed in whole-cell thermograms to denaturation of ribosomal structures. A comparison of partial and immediate full rescan thermograms of A. pernix whole cells indicates that both major peaks represent irreversible thermal transitions. A DNA peak is also identified in the whole-cell thermogram by comparison with the optical data of isolated pure DNA. DNA melting is shown to be irreversible in dilute solution, whereas it is partially reversible in whole cells, owing at least in part, to restricted volume effects. In contrast to mesophilic organisms, hyperthermophilic A. pernix ribosomes are more thermally stable than DNA, but in both organisms, irreversible changes leading to cell death occur owing to ribosomal denaturation.

  17. A new quantitative method to measure activity of ice structuring proteins using differential scanning calorimetry.

    Science.gov (United States)

    Hassa-Roudsari, Majid; Goff, H Douglas

    2012-01-01

    There are very few quantitative assays to measure the activity of antifreeze proteins (AFPs, or Ice Structuring Proteins, ISPs) and these can be prone to various inaccuracies and inconsistencies. Some methods rely only on unassisted visual assessment. When microscopy is used to measure ice crystal size, it is critical that standardized procedures be adopted, especially when image analysis software is used to quantify sizes. Differential Scanning Calorimetry (DSC) has been used to measure the thermal hysteresis activity (TH) of AFPs. In this study, DSC was used isothermally to measure enthalpic changes associated with structural rearrangements as a function of time. Differences in slopes of isothermal heat flow vs. time between winter wheat ISP or AFP type I containing samples, and those without ISP or AFP type I were demonstrated. ISP or AFP type I containing samples had significantly higher slopes compared to those without ISP or AFP type I. Samples with higher concentration of ISP or AFP type I showed higher slope values during the first hour and took up to 3 hr to attain equilibrium. Differences were attributed to activity of the proteins at the ice interface. Proteinaceous activity of ISPs or AFP type I was confirmed by loss of activity after treatment with protease.

  18. Thermal hazard assessment of oxidizer solutions and emulsion explosives utilizing accelerating rate and Dewar calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Jones, D.E.G.; Lightfoot, P.D.; Fouchard, R.C. [Natural Resources Canada, CANMET, Canadian Explosives Research Laboratory, Ottawa, ON (Canada)

    2002-07-01

    Accelerating rate calorimetry (ARC) and adiabatic Dewar calorimetric experiments were carried out on oxidizers used in the manufacture of emulsion explosives, their aqueous solutions, a bulk explosive matrix and a detonator-sensitive packaged explosive. The experiments were carried out in both closed and vented experimental configurations. The effects of water levels on the oxidizer solutions were investigated and the results obtained by using the two different techniques were compared. The Dewar experiments were found to yield a better direct estimation of bulk onset temperatures due to their greater sensitivity and lower 'phi factor'. Onset temperatures of oxidizer solutions measured using the Dewar calorimeter were found to be about 15 degrees C lower than those measured by ARC. Onset temperatures for the same oxidizer solution are lower for open systems than for closed systems. Results for emulsion explosives appeared complex, but indications are that oxidation of the oil phase in air is the first exothermic step in the runaway reaction. Whether this oxidation reaction can generate enough heat to drive the reaction to runaway, is not clear. Further elucidation of the complex exothermic reactions of emulsion explosives and their constituents, using both ARC and Dewar calorimetric techniques is recommended. 8 refs., 1 tab., 9 figs.

  19. Binding of copper to lysozyme: Spectroscopic, isothermal titration calorimetry and molecular docking studies

    Science.gov (United States)

    Jing, Mingyang; Song, Wei; Liu, Rutao

    2016-07-01

    Although copper is essential to all living organisms, its potential toxicity to human health have aroused wide concerns. Previous studies have reported copper could alter physical properties of lysozyme. The direct binding of copper with lysozyme might induce the conformational and functional changes of lysozyme and then influence the body's resistance to bacterial attack. To better understand the potential toxicity and toxic mechanisms of copper, the interaction of copper with lysozyme was investigated by biophysical methods including multi-spectroscopic measurements, isothermal titration calorimetry (ITC), molecular docking study and enzyme activity assay. Multi-spectroscopic measurements proved that copper quenched the intrinsic fluorescence of lysozyme in a static process accompanied by complex formation and conformational changes. The ITC results indicated that the binding interaction was a spontaneous process with approximately three thermodynamical binding sites at 298 K and the hydrophobic force is the predominant driven force. The enzyme activity was obviously inhibited by the addition of copper with catalytic residues Glu 35 and Asp 52 locating at the binding sites. This study helps to elucidate the molecular mechanism of the interaction between copper and lysozyme and provides reference for toxicological studies of copper.

  20. Determination of kinetics and heat of hydrolysis for non-homogenous substrate by isothermal calorimetry.

    Science.gov (United States)

    Tafoukt, D; Soric, A; Sigoillot, J-C; Ferrasse, J-H

    2017-04-01

    The competitiveness of the second-generation bioethanol by biotechnological process requires an effective and quantitative control of biochemical reactions. In this study, the potential of isothermal calorimetry technique to measure heat and kinetics of a non-homogeneous substrate enzymatic hydrolysis is intended. Using this technique, optimum temperature of the enzymes used for lignocellulosic molecules hydrolysis was determined. Thus, the amount of substrate-to-enzyme ratio was highlighted as an important parameter of the hydrolysis yield. Furthermore, a new enzymes' cocktail efficiency consisting of a mix of cellulases and cellobiose dehydrogenase (CDH) was qualified by this technique. The results showed that this cocktail allowed the production of a high amount of gluconic acid that could improve the attractiveness of these second-generation biofuels. From the set of experiments, the hydrolysis heat of wheat straw was derived and a meaningful value of -32.2 ± 3.2 J g(-1) (gram reducing sugars product) is calculated. Then, isothermal measurements were used to determine kinetic constants of the cellulases and CDH mix on wheat straw. Results showed that this enzyme cocktail has an optimal rate at 45 °C in the range of temperatures tested (40-55 °C).

  1. Ring-shaped Calorimetry Information for a Neural eGamma Identification with ATLAS Detector

    CERN Document Server

    Da Fonseca Pinto, Joao Victor; The ATLAS collaboration; Oliveira Damazio, Denis; Seixas, Jose

    2016-01-01

    \\title{Ring-shaped Calorimetry Information for a Neural e/$\\gamma$ Identification with ATLAS Detector} After the successful operation of the Large Hadron Collider resulting with the discovery of the Higgs boson, a new data-taking period (Run 2) has started. For the first time, collisions are produced with energies of 13 TeV in the centre of mass. It is foreseen the luminosity increase, reaching values as high as $10^{34}cm^{-2}s^{-1}$ yet in 2015. These changes in experimental conditions bring a proper environment for possible new physics key-findings. ATLAS is the largest LHC detector and was designed for general-purpose physics studies. Many potential physics channels have electrons or photons in their final states. For efficient studies on these channels precise measurement and identification of such particles is necessary. The identification task consists of disentangling those particles (signal) from collimated hadronic jets (background). Reported work concerns the identification process based on the cal...

  2. Differential scanning calorimetry and surface morphology studies on coated pellets using aqueous dispersions.

    Science.gov (United States)

    Nisar-ur-Rahman; K H, Yuen; Jia Woei, Wong; Khan, Nurzalina A k

    2005-04-01

    The present study was conducted to examine the physicochemical changes during passage of drug through polymeric membranes and observe the surface morphology features of the coated pellets using scanning electron microscopy (SEM). Drug solution was first sprayed around inert pellets to form drug-layered pellets that were coated with two commercial aqueous dispersions namely, Eudragit NE30 and Kollicoat SR30 using bottom-spray fluidized bed technique. Differential scanning calorimetry (DSC) confirmed that no interactions existed between drug and polymers. Small peak of drug was observed in the DSC thermograms of Eudragit NE30 coated pellets indicating that small amount of drug was still present in the polymeric membrane after dissolution. Views of SEM revealed as the coating levels of two types of aqueous dispersions were increased the surface of the pellets become more uniform and compact. Therefore, the diffusion length for dissolution medium to enter the drug layer and dissolved drug to diffuse out would be increased at higher coating levels. The polymer surface of coated pellets after 12 hours dissolution testing seemed to be shrunk and size of the pellets were also reduced indicating the depletion of reservoir layer.

  3. Subsite binding energies of an exo-polygalacturonase using isothermal titration calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Mertens, Jeffrey A., E-mail: Jeffrey.Mertens@ars.usda.gov [Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604 (United States); Hector, Ronald E.; Bowman, Michael J. [Bioenergy Research Unit, National Center for Agricultural Utilization Research, Agricultural Research Service, U.S. Department of Agriculture, 1815 North University Street, Peoria, IL 61604 (United States)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer Thermodynamics of (GalpA){sub n} oligomers binding to an exo-polygalacturonase. Black-Right-Pointing-Pointer Energetics of binding (GalpA){sub n} were determined by ITC. Black-Right-Pointing-Pointer Thermodynamic parameters attributable to individual subsites were determined. - Abstract: Thermodynamic parameters for binding of a series of galacturonic acid oligomers to an exo-polygalacturonase, RPG16 from Rhizopus oryzae, were determined by isothermal titration calorimetry. Binding of oligomers varying in chain length from two to five galacturonic acid residues is an exothermic process that is enthalpically driven and results in extremely tight binding of the substrate to RPG16. Binding energies in combination with prior biochemical data suggests that RPG16 has the potential for five subsites, -1 to +4, with the greatest contribution to binding energies arising from subsite -1/+1. While the enthalpic contribution to binding decreases substantially for subsites +2 to +4, beneficial entropic effects occur in subsites +3 and +4 leading to increased total free energy as the length of oligomer increases. This information will be useful for additional studies in determining the binding contributions of specific amino acids with mutant enzymes.

  4. Sub-picowatt resolution calorimetry with niobium nitride thin-film thermometer

    Energy Technology Data Exchange (ETDEWEB)

    Dechaumphai, Edward; Chen, Renkun, E-mail: rkchen@ucsd.edu [Department of Mechanical and Aerospace Engineering, University of California, San Diego, La Jolla, California 92093 (United States)

    2014-09-15

    High-resolution calorimetry has many important applications such as probing nanoscale thermal transport and studying the thermodynamics of biological and chemical systems. In this work, we demonstrated a calorimeter with an unprecedentedly high resolution at room temperature using a high-performance resistive thermometry material, niobium nitride (NbN{sub x}). Based on a theoretical analysis, we first showed that the heat flux resolution of a resistive-thermometry based calorimeter depends on the parasitic thermal conductance of the device and the temperature coefficient of resistance (TCR) of the thermometer, when the noise is limited by the Johnson noise. Based on this analysis, we then developed a calorimeter using NbN{sub x} as the thermometry material because it possesses both high TCR (∼0.67%/K) and a low thermal conductivity (k ∼ 1.1 W/m K). This calorimeter, when used with the modulated heating scheme, demonstrated an unprecedentedly high power resolution of 0.26 pW at room temperature. In addition, NbN{sub x} based resistive thermometry can also be extended to cryogenic temperature, where the TCR is shown to be significantly higher.

  5. Thermodynamic study of Th(IV) complexes with dicarboxylates by potentiometry and calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Rawat, N.; Nishad, A.; Tomar, B.S.; Manchanda, V.K. [Bhabha Atomic Research Centre, Mumbai (India). Radiochemistry Div.; Sharma, R.S. [Bhabha Atomic Research Centre, Mumbai (India). Research Reactor Services Div.

    2011-07-01

    The thermodynamic quantities ({delta}G{sub c}, {delta}H{sub c} and {delta}S{sub c}) for formation of Th(IV) complexes with dicarboxylic ligands, namely, malonate, succinate, glutarate and adipate were determined using potentiometry and calorimetry. The protonation constants of the dicarboxylate ligands were determined by potentiometric titration of the ligand solution, while the corresponding enthalpy values were taken from the literature. In the case of Th(IV)-malonate, multiple species (ML{sub j}, j = 1-3) were revealed from the potentiometric data, while in the case of higher homologues, the data for only 1:1 complex could be obtained owing to precipitation at higher ligand concentration. The effect of chain length on the thermodynamic parameters of Th(IV)-dicarboxylate complexation was studied. All the complexation reactions were found to be highly entropy driven, which is the characteristic of the hard acid (metal ion) and hard base (ligand) interactions. The T{delta}S{sub c} values for 1:1 complexes were found to be nearly constant while the {delta}H{sub c} values increased from malonate to glutarate and then leveled off in adipate. The thermodynamic data of Th(IV) have been compared with corresponding data for U(VI) and rare earths. (orig.)

  6. PREFACE: XVth International Conference on Calorimetry in High Energy Physics (CALOR2012)

    Science.gov (United States)

    Akchurin, Nural

    2012-12-01

    The XVth International Conference on Calorimetry in High Energy Physics, CALOR2012, was held in Santa Fe, New Mexico from 4-8 June 2012. The series of conferences on calorimetry started in 1990 at Fermilab, and they have been the premier event for calorimeter aficionados, a trend that CALOR2012 upheld. This year, several presentations focused on the status of the major calorimeter systems, especially at the LHC. Discussions on new and developing techniques in calorimetry took a full day. Excellent updates on uses of calorimeters or about ideas that are deeply rooted in particle physics calorimetry in astrophysics and neutrino physics were followed by talks on algorithms and special triggers that rely on calorimeters. Finally, discussions of promising current developments and ongoing R&D work for future calorimeters capped the conference. The field of calorimetry is alive and well, as evidenced by the more than 100 attendees and the excellent quality of over 80 presentations. You will find the written contributions in this volume. The presentations can be found at calor2012.ttu.edu. The first day of the conference was dedicated to the LHC. In two invited talks, Guillaume Unal (CERN) and Tommaso Tabarelli de Fatis (Universita' & INFN Milano Bicocca) discussed the critical role electromagnetic calorimeters play in the hunt for the Standard Model Higgs boson in ATLAS and CMS, respectively. The enhanced sensitivity for light Higgs in the two-gamma decay channel renders electromagnetic calorimeters indispensible. Much of the higher mass region was already excluded for the SM Higgs by the time of this conference, and after less than a month, on 4 July, CERN announced the discovery of a new boson at 125 GeV, a particle that seems consistent with the Higgs particle so far. Once again, without the electromagnetic calorimeters, this would not have been possible. Professor Geoffrey West from the Santa Fe Institute gave the keynote address. His talk, 'Universal Scaling Laws

  7. Breath test measurements in combination with indirect calorimetry for estimation of 13C-leucine oxidation in mink (Mustela vison)

    DEFF Research Database (Denmark)

    Tauson, Anne-Helene; Ali, Abdalla; Kanska, Katarzyna

    2000-01-01

    Gas exchange measurements by means of indirect calorimetry can be used to calculate quantitative substrate oxidation. The results represents average net oxidation values (substrate disappearance rate), but they cannot describe the dynamics of the oxidation processes. Breath test measurements...... to feeding and fasting. Twelve 1-year-old male mink (Mustela vison) were measured in each five consecutive periods by means of indirect calorimetry and simultaneous breath test. In Periods 1, 3 and 5, each lasting 3 days, the animals were fed ad libitum and Periods 2 and 4 were fasting periods, each of 48 h...... before measurements started and expired air was then sucked out of the respiration chamber and collected into breath bags at frequent intervals until 5.5 h after the start of measurements. The ratio of 13C/12C was measured by means of an IRIS infrared analyser and results are reported in terms of delta...

  8. A New Method for the Determination of the Specific Heat Capacity Using Laser-Flash Calorimetry Down to 77K

    Science.gov (United States)

    Göbel, A.; Hemberger, F.; Vidi, S.; Ebert, H.-P.

    2013-05-01

    A new method for evaluation of the specific heat capacity in the temperature regime between 77K and 330K using laser-flash calorimetry is presented. Usually, laser-flash calorimetry is accomplished by performing an additional laser-flash measurement on a reference specimen with a known specific heat capacity and by comparing the maximum rear-side temperatures rises. In this study, the calibration is achieved by comparison of the rear-side temperature rise to specific-heat-capacity data determined by other methods in an adjacent temperature regime. Subsequently, the thus yielded proportional factor is used for the evaluation of the specific heat capacity from laser-flash measurements at temperatures where no specific-heat-capacity data are available. The reliability of this method is shown by performing measurements on a material with known specific heat capacity, aluminum oxide. Furthermore, the specific heat capacity and thermal conductivity of borosilicate crown glass (BK7) was determined experimentally.

  9. Interaction of insulin, cholesterol-derivatized mannan, and carboxymethyl chitin with liposomes: A differential scanning calorimetry study

    OpenAIRE

    M. Tabbakhian; Rogers, J.A.

    2012-01-01

    The interaction of drugs and polymers used to incorporate in or surface modify/coat the liposomes can affect the phase transition, fluidity and other physical properties as well as in vivo fate of vesicles. In this study, differential scanning calorimetry (DSC) was used to investigate changes in the temperature and the enthalpy of phase transition of liposomes of various electrical charges following interaction with carboxymethyl chitin (CM-chitin) as a hydrophilic polymer, cholesterol-deriva...

  10. Comparative results of autogenous ignition temperature measurements by ASTM G 72 and pressurized scanning calorimetry in gaseous oxygen

    Science.gov (United States)

    Bryan, C. J.; Lowrie, R.

    1986-01-01

    The autogenous ignition temperature of four materials was determined by ASTM (G 72) and pressurized differential scanning calorimetry at 0.68-, 3.4-, and 6.8-MPa oxygen pressure. All four materials were found to ignite at lower temperatures in the ASTM method. The four materials evaluated in this program were Neoprene, Vespel SP-21, Fluorel E-2160, and nylon 6/6.

  11. Differential Scanning Calorimetry and Infrared Spectroscopy Combined with Chemometric Analysis to the Determination of Coffee Adulteration by Corn

    OpenAIRE

    Brondi, Ariadne M.; Torres, Claudia; Garcia, Jerusa S.; Trevisan, Marcello G.

    2017-01-01

    Roasted and ground coffee is targeted by fraudulent addiction of products. In this way the determination of contaminants in coffee has economic and nutritional importance. In this study, the coffee adulteration by corn were detected using DSC (differential scanning calorimetry) and FTIR (Fourier transform infrared spectroscopy) coupled to PCA (principal component analysis), and PLS (partial least squares) models. Three different levels of roasted and ground Coffea arabica L. were used to prep...

  12. Quantifying Natural Organic Matter with Calorimetry - assessing system complexity to build a central view C stability

    Science.gov (United States)

    Liles, G. C.; Bower, J.; Henneberry, Y.; Horwath, W. R.

    2010-12-01

    Characterizing the status and stability of natural organic matter (NOM) is central to understanding the flux, attenuation and function of C in the biosphere. A diversity of stabilizing factors (climate, mineralogy, chemical recalcitrance) have required a range of analytical approaches and methods that are site or discipline specific making unified assessments difficult. Aggregated, these efforts support our working models of NOM as a dynamic body but, overall, lack analytical simplicity and reproducibility. In particular, the robustness and resolution to assess NOM across systems of increasing complexity is lacking. Calorimetry has been central to chemistry and material science characterizing a broad range of organic and inorganic materials and their mixtures illustrating composition, purity and stability. Differential scanning calorimetry - thermogravimetry (DSC-TG) provides the flexibility and resolution to quantify the complexity found within NOM with precise quantification of material mass loss (TG) and energetic (DSC) under controlled atmospheric and heating conditions. DSC-TG is data rich providing a range of qualitative and quantitative metrics: peak shape, exothermic energy yield, mass loss, and determination of enthalpy, to characterize NOM stability from low (dissolved organic carbon - DOC) through high (compost and soils) molecular weights (MW) at increasing levels of organo-metallic complexity. Our research investigates the influence of biochemical recalcitrance and its alteration by oxides employing three natural systems of varying complexity as experimental models: aquatic - DOC and DOC with metal flocculants (low MW - low complexity), compost - processed with and without metal oxides (mixed MW - increasing complexity) and forest soils - under varying management and litter inputs (mixed MW - most complexity). Samples were analyzed by DSC-TG (zero-air - 20 C/min - ambient to > 800C) and assessed for three temperature/exothermic reaction regions (200

  13. Active metabolic weight estimation using bioimpedance, indirect calorimetry and the clino-ortho maneuver.

    Science.gov (United States)

    Cadena, Miguel; Azpiroz, Joaquin; Borja, Gisella; Medel, Humberto; Sandoval, Hector; Rodriguez, Fausto; Flores, Francisco; Flores, Pedro

    2010-01-01

    The resting energy expenditure (REE) and substrate utilization are computed by indirect calorimetry technique (ICT). The REE represents 80-85% of the total energy expenditure (TEE) but only accounts for the 7% of the actual body weight (ABW). The TEE is produced by the organs plus muscles, whereas the REE accounts only for the main organs. An important problem comes up when the REE is computed throughout the fat free mass (FFM) computation or anthropometric measurements because they do not explain the tremendous catabolic variability by ICT when subjects show the same body composition. Therefore, the aim of this work is to develop a method to compute the metabolic active weight (MAW) as a new form that may help to understand the catabolic activity of the body composition. The premise was the clino-ortho maneuver can split the ABW in two parts: one in which the MAW reflects the FFM catabolism while the second part was not considered since there is not energy requirement in it. The experiment design studied 37 young volunteers undergoing the clino-ortho maneuver during fast and postprandial conditions. The results showed REE increments of 21% during phase I (fast), while in phase II (postprandial) only 14% was achieved in ortho-postprandial. Therefore, the computed MAWs were 65.5Kg and 58Kg, respectively, when the ABW average was 70 Kg and the FFM was 50 Kg. One first conclusion was that the 15.5 Kg of the MAW above the FFM could explain a catabolic equivalence which can be exclusively related to the fast-ortho position which can help to classify exclusively the dynamic over activity of the FFM.

  14. Analysis of IgG kinetic stability by differential scanning calorimetry, probe fluorescence and light scattering.

    Science.gov (United States)

    Nemergut, Michal; Žoldák, Gabriel; Schaefer, Jonas V; Kast, Florian; Miškovský, Pavol; Plückthun, Andreas; Sedlák, Erik

    2017-11-01

    Monoclonal antibodies of the immunoglobulin G (IgG) type have become mainstream therapeutics for the treatment of many life-threatening diseases. For their successful application in the clinic and a favorable cost-benefit ratio, the design and formulation of these therapeutic molecules must guarantee long-term stability for an extended period of time. Accelerated stability studies, e.g., by employing thermal denaturation, have the great potential for enabling high-throughput screening campaigns to find optimal molecular variants and formulations in a short time. Surprisingly, no validated quantitative analysis of these accelerated studies has been performed yet, which clearly limits their application for predicting IgG stability. Therefore, we have established a quantitative approach for the assessment of the kinetic stability over a broad range of temperatures. To this end, differential scanning calorimetry (DSC) experiments were performed with a model IgG, testing chaotropic formulations and an extended temperature range, and they were subsequently analyzed by our recently developed three-step sequential model of IgG denaturation, consisting of one reversible and two irreversible steps. A critical comparison of the predictions from this model with data obtained by an orthogonal fluorescence probe method, based on 8-anilinonaphthalene-1-sulfonate binding to partially unfolded states, resulted in very good agreement. In summary, our study highlights the validity of this easy-to-perform analysis for reliably assessing the kinetic stability of IgGs, which can support accelerated formulation development of monoclonal antibodies by ranking different formulations as well as by improving colloidal stability models. © 2017 The Protein Society.

  15. Thermodynamic characterization of OsGID1-gibberellin binding using calorimetry and docking simulations.

    Science.gov (United States)

    Xiang, Hongyu; Takeuchi, Hiromi; Tsunoda, Yuki; Nakajima, Masatoshi; Murata, Katsuyoshi; Ueguchi-Tanaka, Miyako; Kidokoro, Shun-ichi; Kezuka, Yuichiro; Nonaka, Takamasa; Matsuoka, Makoto; Katoh, Etsuko

    2011-01-01

    Gibberellins (GAs) are phytohormones regulating various developmental processes in plants. In rice, the initial GA-signaling events involve the binding of a GA to the soluble GA receptor protein, GID1. Although X-ray structures for certain GID1/GA complexes have recently been determined, an examination of the complexes does not fully clarify how GID1s discriminate among different GAs. Herein, we present a study aimed at defining the types of forces important to binding via a combination of isothermal titration calorimetry (ITC) and computational docking studies that employed rice GID1 (OsGID1), OsGID1 mutants, which were designed to have a decreased possible number of hydrogen bonds with bound GA, and GA variants. We find that, in general, GA binding is enthalpically driven and that a hydrogen bond between the phenolic hydroxyl of OsGID1 Tyr134 and the C-3 hydroxyl of a GA is a defining structural element. A hydrogen-bond network that involves the C-6 carboxyl of a GA that directly hydrogen bonds the hydroxyl of Ser198 and indirectly, via a two-water-molecule network, the phenolic hydroxyl of Tyr329 and the NH of the amide side-chain of Asn255 is also important for GA binding. The binding of OsGID1 by GA(1) is the most enthalpically driven association found for the biologically active GAs evaluated in this study. This observation might be a consequence of a hydrogen bond formed between the hydroxyl at the C-13 position of GA(1) and the main chain carbonyl of OsGID1 Phe245. Our results demonstrate that by combining ITC experiments and computational methods much can be learned about the thermodynamics of ligand/protein binding. Copyright © 2010 John Wiley & Sons, Ltd.

  16. A calorimetry system for metabolism trials Sistema de calorimetria para estudos de metabolismo

    Directory of Open Access Journals (Sweden)

    N.M. Rodríguez

    2007-04-01

    Full Text Available An indirect calorimetry system for rapid determination of CO2 and CH4 production and O2 consumption to estimate heat production of animals was built at Escola de Veterinária da Universidade Federal de Minas Gerais, Brazil. Procedures for determination of correction and calibration factors for gas analyzers and the whole system, using standard test gases were described. In addition, a metabolic trial was performed to evaluate heat production of lambs fed ad libitum. It is concluded that the system is suitable for heat production determinations in small and medium size animals.Um sistema de calorimetria para a determinação rápida da produção de CO2 e CH4 e do consumo de O2 de animais para o cálculo da produção de calor foi construído na Escola de Veterinária da Universidade Federal de Minas Gerais. Foram descritos os procedimentos para a determinação dos fatores de correção dos analisadores e calibração do sistema utilizando-se gases padrão. Adicionalmente, um ensaio de metabolismo foi realizado para se avaliar a produção de calor de ovinos alimentados ad libitum. Conclui-se que o sistema está apto para determinações de produção de calor em animais de pequeno e médio porte.

  17. Modulation calorimetry in diamond anvil cells. II. Joule-heating design and prototypes

    Science.gov (United States)

    Geballe, Zachary M.; Struzhkin, Viktor V.; Townley, Andrew; Jeanloz, Raymond

    2017-04-01

    Part I shows that quantitative measurements of heat capacity are theoretically possible inside diamond anvil cells via high-frequency Joule heating (100 kHz-10 MHz), opening up the possibility of new methods to detect and characterize transformations at high-pressure such as the glass transitions, melting, magnetic orderings, and the onset of superconductivity. Here, we test the possibility outlined in Part I, using prototypes and detailed numerical models. First, a coupled electrical-thermal numerical model shows that specific heat of metals inside diamond cells can be measured directly using ˜1 MHz frequency, with test physical models of high-pressure experiments, i.e., diamond-cell mock-ups. Metal foils of 2-6 μm-thickness are clamped between glass insulation inside diamond anvil cells. Fitting data from 10 Hz to ˜30 kHz, we infer the specific heat capacities of Fe, Pt, and Ni with ±20%-30% accuracy. The electrical test equipment generates -80 dBc spurious harmonics, which overwhelm the thermally induced harmonics at higher frequencies, disallowing the high precision expected from numerical models. An alternative Joule-heating calorimetry experiment, on the other hand, does allow absolute measurements with thermal effusivity, √{ρc k } (ρ, c, and k being density, specific heat, and thermal conductivity), of the insulation surrounding a thin-film heater. Using a ˜50 nm-thick Pt heater surrounded by glass and 10 Hz-300 kHz frequency, we measure thermal effusivity with ±6 % accuracy inside the sample chamber of a diamond anvil cell.

  18. Thermal porosity analysis of croscarmellose sodium and sodium starch glycolate by differential scanning calorimetry.

    Science.gov (United States)

    Faroongsarng, Damrongsak; Peck, Garnet E

    2003-12-30

    The aim of the study was to demonstrate the applicability of differential scanning calorimetry (DSC) on porosity analysis for cellulose and starch. Croscarmellose sodium (CCS) and sodium starch glycolate (SSG) were allowed to sorb moisture in 85%, 90%, 95%, and 100% relative humidity (RH) at 40 degrees C for 24 hours. The pretreated samples were then subjected to DSC running temperature ranging from 25 degrees C to -50 degrees C at a cooling rate of 10 degrees C/min. The cooling traces of water crystallization, if present, were transformed to porosity distribution via capillary condensation using Kelvin's equation. The porosity analysis of CCS and SSG was also done using nitrogen adsorption as a reference method. It was found that sorbed water could not be frozen (in cases of 85% and 90% RH) until the moisture content exceeded a cutoff value (in cases of 95% and 100% RH). The nonfreezable moisture content was referred to tightly bound, plasticizing water, whereas the frozen one may be attributed to loosely bound water condensation in pore structure of CCS and SSG surfaces. Not only capillary condensation but also the tightly bound, nonfreezable monolayer water lying along the inner pores of the surface contributed to porosity determination. Good agreement with less than 5% deviation of mean pore size was observed when the results were compared with nitrogen adsorption. The narrower pore size distributions, however, were obtained because of the limitations of the technique. It was concluded that pore analysis by DSC could be successful. Further research needs to be done to account for limitations and to extend the applicability of the technique.

  19. Isothermal titration calorimetry uncovers substrate promiscuity of bicupin oxalate oxidase from Ceriporiopsis subvermispora

    Directory of Open Access Journals (Sweden)

    Hassan Rana

    2016-03-01

    Full Text Available Isothermal titration calorimetry (ITC may be used to determine the kinetic parameters of enzyme-catalyzed reactions when neither products nor reactants are spectrophotometrically visible and when the reaction products are unknown. We report here the use of the multiple injection method of ITC to characterize the catalytic properties of oxalate oxidase (OxOx from Ceriporiopsis subvermispora (CsOxOx, a manganese dependent enzyme that catalyzes the oxygen-dependent oxidation of oxalate to carbon dioxide in a reaction coupled with the formation of hydrogen peroxide. CsOxOx is the first bicupin enzyme identified that catalyzes this reaction. The multiple injection ITC method of measuring OxOx activity involves continuous, real-time detection of the amount of heat generated (dQ during catalysis, which is equal to the number of moles of product produced times the enthalpy of the reaction (ΔHapp. Steady-state kinetic constants using oxalate as the substrate determined by multiple injection ITC are comparable to those obtained by a continuous spectrophotometric assay in which H2O2 production is coupled to the horseradish peroxidase-catalyzed oxidation of 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid and by membrane inlet mass spectrometry. Additionally, we used multiple injection ITC to identify mesoxalate as a substrate for the CsOxOx-catalyzed reaction, with a kinetic parameters comparable to that of oxalate, and to identify a number of small molecule carboxylic acid compounds that also serve as substrates for the enzyme.

  20. Evaluation of peritoneal tissue by means of differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Łukasz Pietrzyk

    2012-01-01

    Full Text Available Abdominal surgeries alter the integrity of the peritoneal layer and cause imbalances among immunological, inflammatory and angiogenic mechanisms within the tissue. During laparoscopic procedures a protective function of the peritoneal layer can be disturbed by the gas used to create a pneumoperitoneum. The aim of this study was to characterize peritoneal tissue by means of differential scanning calorimetry (DSC as a reference for future investigations on the influence of surgical procedures on the physicochemical state of the peritoneum. Thirty-seven patients participated in the study. Patients were divided into three groups according to the type of surgery: group H — patients who underwent hernia repair; group Ch — patients who underwent laparoscopic cholecystectomy; and group C — patients operated due to rectal cancer. It was observed that onset temperature (To, denaturation temperature (Tm and change of enthalpy (ΔH during thermal denaturation of peritoneal collagen in were significantly different for these three groups of patients. The mean values of onset temperature (To and denaturation temperature (Tm in group H were significantly lower, while DH in this group was significantly higher than in the two other groups (Ch and C. This preliminary study does not answer whether the differences in collagen denaturation found in peritoneal tissue from different groups of patients resulted from a different inherent state of the tissue, or from surgical procedures. However, the results suggest that DSC is an appropriate method to study subtle changes in the physicochemical condition of the peritoneum using small samples obtained during surgical procedures. (Folia Histochemica et Cytobiologica 2011; Vol. 49, No. 4, pp. 700–705

  1. Quantifying high-affinity binding of hydrophobic ligands by isothermal titration calorimetry.

    Science.gov (United States)

    Krainer, Georg; Broecker, Jana; Vargas, Carolyn; Fanghänel, Jörg; Keller, Sandro

    2012-12-18

    A fast and reliable quantification of the binding thermodynamics of hydrophobic high-affinity ligands employing a new calorimetric competition experiment is described. Although isothermal titration calorimetry is the method of choice for a quantitative characterization of intermolecular interactions in solution, a reliable determination of a dissociation constant (K(D)) is typically limited to the range 100 μM > K(D) > 1 nM. Interactions displaying higher or lower K(D) values can be assessed indirectly, provided that a suitable competing ligand is available whose K(D) falls within the directly accessible affinity window. This established displacement assay, however, requires the high-affinity ligand to be soluble at high concentrations in aqueous buffer and, consequently, poses serious problems in the study of protein binding involving small-molecule ligands dissolved in organic solvents--a familiar case in many drug-discovery projects relying on compound libraries. The calorimetric competition assay introduced here overcomes this limitation, thus allowing for a detailed thermodynamic description of high-affinity receptor-ligand interactions involving poorly water-soluble compounds. Based on a single titration of receptor into a dilute mixture of the two competing ligands, this competition assay provides accurate and precise values for the dissociation constants and binding enthalpies of both high- and moderate-affinity ligands. We discuss the theoretical background underlying the approach, demonstrate its practical application to metal ion chelation and high-affinity protein-inhibitor interactions, and explore its potential and limitations with the aid of simulations and statistical analyses.

  2. Volumetric characterization of ester- and ether-linked lipid bilayers by pressure perturbation calorimetry and densitometry.

    Science.gov (United States)

    Tamai, Nobutake; Nambu, Yuko; Tanaka, Saeko; Goto, Masaki; Matsuki, Hitoshi; Kaneshina, Shoji

    2012-04-01

    We investigated the thermotropic volume behavior of dimyristoylphosphatidylcholine (DMPC), dipalmitoylphosphatidylcholine (DPPC) and dihexadecylphosphatidylcholine (DHPC) membranes using pressure perturbation calorimetry (PPC) and densitometry. The ln φ(2) vs temperature curves (φ(2): apparent molar volume of phospholipid) obtained from the PPC data using an analysis method that we developed agreed with the results from the density measurements for these lipids within the relative difference of about 0.62%. From those curves, the volume changes with the main transition were estimated at 18.0±0.49, 23.5±2.33 and 23.0±0.33 cm(3) mol(-1) for DMPC, DPPC and DHPC, respectively. For DPPC and DMPC, the average volume per methylene group of the hydrocarbon chains v(CH2) calculated by referring to the procedure by Nagle and Wilkinson was consistent with the previous result, which indicates that the DPPC bilayer in the gel state has denser hydrophobic bilayer core than the DMPC bilayer. For DHPC, the volume of the headgroup region v(H) was calculated to be 244 Å(3) by assuming that v(CH2) of DHPC equals that of DPPC above 45°C. This value was comparable to that of DPPC when the volume of the carbonyl groups was considered, which may signify that there is no significant conformational difference in the polar headgroups of both phospholipids. However, it was suggested from the consideration on v(H) of DHPC at 20°C that expansion of the headgroup region should occur as the interdigitated structure is formed, which means some conformational change of the headgroup region is induced by the interdigitation. Copyright © 2011 Elsevier B.V. All rights reserved.

  3. Beam studies of the segmented resistive WELL: A potential thin sampling element for digital hadron calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Arazi, Lior, E-mail: lior.arazi@weizmann.ac.il [Weizmann Institute of Science, Rehovot (Israel); Davide Rocha Azevedo, Carlos [I3N—Physics Department, University of Aveiro, 3810-193 Aveiro (Portugal); Breskin, Amos; Bressler, Shikma; Moleri, Luca [Weizmann Institute of Science, Rehovot (Israel); Natal da Luz, Hugo [University of Coimbra, Coimbra (Portugal); Oliveri, Eraldo [CERN, Geneva (Switzerland); Pitt, Michael; Rubin, Adam [Weizmann Institute of Science, Rehovot (Israel); Marques Ferreira dos Santos, Joaquim [University of Coimbra, Coimbra (Portugal); Filipe Calapez de Albuquerque Veloso, João [I3N—Physics Department, University of Aveiro, 3810-193 Aveiro (Portugal); Paul White, Andrew [University of Texas, Arlington (United States)

    2013-12-21

    Thick Gas Electron Multipliers (THGEMs) have the potential of constituting thin, robust sampling elements in Digital Hadron Calorimetry (DHCAL) at future colliders. We report on recent beam studies of new single- and double-THGEM-like structures: the multiplier is a Segmented Resistive WELL (SRWELL) – a single-faced THGEM in contact with a segmented resistive layer inductively coupled to readout pads. Several 10×10 cm{sup 2} configurations with a total thickness of 5–6 mm (excluding electronics) with 1 cm{sup 2} pads were investigated with muons and pions. The pads were coupled to a scalable readout system APV chip, APV-SRS (Raymond et al. [22]). Detection efficiencies in the 98% range were recorded with an average pad-multiplicity of ∼1.1. The resistive anode resulted in efficient discharge damping, with potential drops of a few volts; the discharge probabilities were ∼10{sup −7} for muons and ∼10{sup −6} for pions, at rates of a few kHz/cm{sup 2} and for detectors in the double-stage configuration. Further optimization work and research on larger detectors are underway. -- Highlights: •THGEM-based detectors with resistive anodes are proposed as DHCAL sampling elements. •Single- and double-stage detectors were successfully tested with muons and pions. •Detectors were 10×10 cm{sup 2} in size, 5–6 mm thick (excluding electronics). •Readout provided by SRS-APV chip coupled to 64 1×1 cm{sup 2} pads. •Detectors efficiencies were >97% at 1.1 multiplicity with effective spark damping.

  4. Influence of passivation on ageing of nano-aluminum: Heat flux calorimetry and microstructural studies

    Energy Technology Data Exchange (ETDEWEB)

    Pisharath, Sreekumar, E-mail: sreekumar@ntu.edu.sg; Zhang, Fan; Ang, How Ghee

    2016-07-10

    Highlights: • Ageing behavior of nano-aluminum is investigated by heat flux calorimetry. • Ageing process proceeds by hydrolysis releasing 13.4 kJ/g of heat. • Organo-silane coatings act as excellent passivation barrier against ageing. • Cumulative energy release for coated n-Al drops markedly during storage. • Non polar organo-silane coating offers improved ageing characteristics. - Abstract: Aluminum nanoparticles (n-Al) have been considered as promising fuel for incorporation in propellants and explosives to improve their performance. To prevent oxidation during storage, we investigate the effect of organic coatings on reducing oxidation of n-Al via accelerated ageing tests. The n-Al was modified with 3 different functional organic silanes. The presence of organic coatings on surface-modified n-Al was confirmed by X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). In the accelerated ageing tests, the pristine and surface-modified n-Al were kept at elevated humidity and temperatures. The ageing process was monitored via heat flow calorimeter. The effectiveness of the organosilane coatings as barrier to hydrolysis and oxidation of n-Al was evaluated from the heat released during ageing, as well as the analysis of active Al content of the aged samples. It is found that although the pristine n-Al possesses a natural Al{sub 2}O{sub 3} passivation layer, it cannot prevent n-Al from fully getting oxidized under the conditions tested. Organosilane coatings act as excellent barrier against diffusion of moisture preventing n-Al inside from oxidation. This study shows that all 3 kinds of organosilane-modified n-Al have much better resistance to ageing than the pristine n-Al, therefore demonstrates surface-modification of n-Al is a promising technique to extend the shelf life of n-Al during storage.

  5. Fasting substrate oxidation at rest assessed by indirect calorimetry: is prior dietary macronutrient level and composition a confounder?

    Science.gov (United States)

    Miles-Chan, J L; Dulloo, A G; Schutz, Y

    2015-07-01

    Indirect calorimetry, the measurement of O₂ consumption and CO₂ production, constitutes an invaluable tool as the most common method for analyzing whole-body energy expenditure, and also provides an index of the nature of macronutrient substrate oxidation--namely, carbohydrate (CHO) versus fat oxidation. The latter constitutes a key etiological factor in obesity as this condition can only develop when total fat oxidation is chronically lower than total exogenous fat intake. The standardization of indirect calorimetry measurements is essential for accurately tracking the relative proportion of energy expenditure derived from CHO and fat oxidation. Here we analyze literature data to show that the average fasting respiratory quotient typically shifts from approximately 0.80 to 0.90 (indicating a doubling of resting CHO oxidation) in response to a switch in dietary CHO intake (as % energy) from 30 to 60%. This underscores the importance of taking into account dietary macronutrient composition prior to indirect calorimetry studies in the interpretation of data on substrate utilization and oxidation.

  6. A Statistical Method and Tool to Account for Indirect Calorimetry Differential Measurement Error in a Single-Subject Analysis.

    Science.gov (United States)

    Tenan, Matthew S

    2016-01-01

    Indirect calorimetry and oxygen consumption (VO2) are accepted tools in human physiology research. It has been shown that indirect calorimetry systems exhibit differential measurement error, where the error of a device is systematically different depending on the volume of gas flow. Moreover, systems commonly report multiple decimal places of precision, giving the clinician a false sense of device accuracy. The purpose of this manuscript is to demonstrate the use of a novel statistical tool which models the reliability of two specific indirect calorimetry systems, Douglas bag and Parvomedics 2400 TrueOne, as univariate normal distributions and implements the distribution overlapping coefficient to determine the likelihood that two VO2 measures are the same. A command line implementation of the tool is available for the R programming language as well as a web-based graphical user interface (GUI). This tool is valuable for clinicians performing a single-subject analysis as well as researchers interested in determining if their observed differences exceed the error of the device.

  7. Measuring energy expenditure in cardiac patients using the Body Media Armband versus indirect calorimetry. A validation study.

    Science.gov (United States)

    Cole, P J; LeMura, L M; Klinger, T A; Strohecker, K; McConnell, T R

    2004-09-01

    The purpose of this study was to compare differences in energy expenditure using the newly developed SenseWear Armband body monitor to indirect calorimetry in cardiac rehabilitation patients. Twenty-four (62+/-8.1 years) patients completed steady state exercise for 8 minutes on 4 modes of exercise (arm ergometry, treadmill walking, recumbent stepping and rowing ergometry). Total cumulative kilojoules were recorded simultaneously by indirect calorimetry and the SenseWear Armband. Statistical analyses assessed the degree of agreement between the 2 measurement methods and 3 different versions of the SenseWear software. The correlations between indirect calorimetry and version 2.2 of the SenseWear armband for arm and rowing ergometry, the treadmill and recumbent stepper were r=0.90, r=0.67, r=0 .80 and r=0.74, respectively. There were no between method differences during arm ergometry (pBodyMedia SenseWear Armband appears to be exercise modality dependent in those with heart disease when using software developed for the general population. Therefore, the information should be interpreted cautiously, particularly during treadmill walking and rowing. Initial experiments with cardiac-focused software are promising, but preliminary.

  8. Proceedings of the Eleventh International Conference on Calorimetry in Particle Physics

    Science.gov (United States)

    Cecchi, Claudia

    The Pamela silicon tungsten calorimeter / G. Zampa -- Design and development of a dense, fine grained silicon tungsten calorimeter with integrated electronics / D. Strom -- High resolution silicon detector for 1.2-3.1 eV (400-1000 nm) photons / D. Groom -- The KLEM high energy cosmic rays collector for the NUCLEON satellite mission / M. Merkin (contribution not received) -- The electromagnetic calorimeter of the Hera-b experiment / I. Matchikhilian -- The status of the ATLAS tile calorimeter / J. Mendes Saraiva -- Design and mass production of Scintillator Pad Detector (SPD) / Preshower (PS) detector for LHC-b experiment / E. Gushchin -- Study of new FNAL-NICADD extruded scintillator as active media of large EMCal of ALICE at LHC / O. Grachov -- The CMS hadron calorimeter / D. Karmgard (contribution not received) -- Test beam study of the KOPIO Shashlyk calorimeter prototype / A. Poblaguev -- The Shashlik electro-magnetic calorimeter for the LHCb experiment / S. Barsuk -- Quality of mass produced lead-tungstate crystals / R. Zhu -- Status of the CMS electromagnetic calorimeter / J. Fay -- Scintillation detectors for radiation-hard electromagnetic calorimeters / H. Loehner -- Energy, timing and two-photon invariant mass resolution of a 256-channel PBWO[symbol] calorimeter / M. Ippolitov -- A high performance hybrid electromagnetic calorimeter at Jefferson Lab / A. Gasparian -- CsI(Tl) calorimetry on BESHI / T. Hu (contribution not received) -- The crystal ball and TAPS detectors at the MAMI electron beam facility / D. Watts -- Front-end electronics of the ATLAS tile calorimeter / R. Teuscher -- The ATLAS tilecal detector control system / A. Gomes -- Performance of the liquid argon final calibration board / C. de la Taille -- Overview of the LHCb calorimeter electronics / F. Machefert -- LHCb preshower photodetector and electronics / S. Monteil -- The CMS ECAL readout architecture and the clock and control system / K. Kloukinas -- Test of the CMS-ECAL trigger

  9. Differential scanning calorimetry study of glycerinated rabbit psoas muscle fibres in intermediate state of ATP hydrolysis

    Directory of Open Access Journals (Sweden)

    Farkas Nelli

    2007-06-01

    Full Text Available Abstract Background Thermal denaturation experiments were extended to study the thermal behaviour of the main motor proteins (actin and myosin in their native environment in striated muscle fibres. The interaction of actin with myosin in the highly organized muscle structure is affected by internal forces; therefore their altered conformation and interaction may differ from those obtained in solution. The energetics of long functioning intermediate states of ATP hydrolysis cycle was studied in muscle fibres by differential scanning calorimetry (DSC. Results SETARAM Micro DSC-II was used to monitor the thermal denaturation of the fibre system in rigor and in the presence of nucleotide and nucleotide analogues. The AM.ADP.Pi state of the ATP hydrolysis cycle has a very short lifetime therefore, we mimicked the different intermediate states with AMP.PNP and/or inorganic phosphate analogues Vi and AlF4 or BeFx. Studying glycerol-extracted muscle fibres from the rabbit psoas muscle by DSC, three characteristic thermal transitions were detected in rigor. The thermal transitions can be assigned to myosin heads, myosin rods and actin with transition temperatures (Tm of 52.9 ± 0.7°C, 57.9 ± 0.7°C, 63.7 ± 1.0°C. In different intermediate states of the ATP hydrolysis mimicked by nucleotide analogues a fourth thermal transition was also detected which is very likely connected with nucleotide binding domain of myosin and/or actin filaments. This transition temperature Tm4 depended on the mimicked intermediate states, and varied in the range of 66°C – 77°C. Conclusion According to DSC measurements, strongly and weakly binding states of myosin to actin were significantly different. In the presence of ADP only a moderate change of the DSC pattern was detected in comparison with rigor, whereas in ADP.Pi state trapped by Vi, AlF4 or BeFx a remarkable stabilization was detected on the myosin head and actin filament which is reflected in a 3.0 – 10.0

  10. Characterization of ß-trypsin at acid pH by differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Bittar E.R.

    2003-01-01

    Full Text Available Trypsin is a serino-protease with a polypeptide chain of 223 amino acid residues and contains six disulfide bridges. It is a globular protein with a predominance of antiparallel ß-sheet and helix in its secondary structure and has two domains with similar structures. We assessed the stability of ß-trypsin in the acid pH range using microcalorimetric (differential scanning calorimetry techniques. Protein concentrations varied in the range of 0.05 to 2.30 mg/ml. Buffer solutions of 50.0 mM ß-alanine and 20.0 mM CaCl2 at different pH values (from 2.0 to 4.2 and concentrations of sorbitol (1.0 and 2.0 M, urea (0.5 M or guanidinium hydrochloride (0.5 and 1.0 M were used. The data suggest that we are studying the same conformational transition of the protein in all experimental situations using pH, sorbitol, urea and guanidinium hydrochloride as perturbing agents. The observed van't Hoff ratios (deltaHcal/deltaHvH of 1.0 to 0.5 in the pH range of 3.2 to 4.2 suggest protein aggregation. In contrast, deltaHcal/deltaHvH ratios equal to one in the pH range of 2.0 to 3.2 suggest that the protein unfolds as a monomer. At pH 3.00, ß-trypsin unfolded with Tm = 54ºC and deltaH = 101.8 kcal/mol, and the change in heat capacity between the native and unfolded forms of the protein (deltaCp was estimated to be 2.50 ± 0.07 kcal mol-1 K-1. The stability of ß-trypsin calculated at 298 K was deltaG D = 5.7 kcal/mol at pH 3.00 and deltaG D = 15.2 kcal/mol at pH 7.00, values in the range expected for a small globular protein.

  11. Characteristics and thermodynamics of the interaction of 6-shogaol with human serum albumin as studied by isothermal titration calorimetry

    Directory of Open Access Journals (Sweden)

    Shevin Rizal Feroz

    Full Text Available ABSTRACT The interaction between 6-shogaol, a pharmacologically active ginger constituent, and human serum albumin (HSA, the main in vivo drug transporter, was investigated using isothermal titration calorimetry (ITC. The value of the binding constant, Ka (5.02 ± 1.37 × 104 M−1 obtained for the 6-shogaol-HSA system suggested intermediate affinity. Analysis of the ITC data revealed feasibility of the binding reaction due to favorable enthalpy and entropy changes. The values of the thermodynamic parameters suggested involvement of van der Waals forces, hydrogen bonds and hydrophobic interactions in the 6-shogaol-HSA complex formation.

  12. An experimental investigation to evaluate the heating value of palm oil waste by calorimetry. Paper no. IGEC-1-040

    Energy Technology Data Exchange (ETDEWEB)

    Supeni, E.E.; Megat Mohd, M.H.; Mohd Sapuan, S.; Nor Maria, A.; Ismail, M.Y.; Thoguluva, R.V. [Univ. Putra Malaysia, Dept. of Mechanical and Manufacturing Engineering, Faculty of Engineering, Selangor D.E., (Malaysia)]. E-mail: eris@eng.upm.edu.my; Chuah, T.G. [Univ. Putra Malaysia, Dept. of Chemical and Environmental Engineering, Faculty of Engineering, Selangor D.E., (Malaysia)

    2005-07-01

    A palm oil mill produces palm oil and kernel palm oil as main products and biomass residue (fiber and shell). This excess biomass residue can be used as fuel in boilers to meet energy and process heat demand in the industries. Quality of the palm oil waste (POW) is characterized by low fixed carbon and relatively high moisture content which may affect the heating value (HV). By applying the principle of calorimetry, a bomb calorimeter is utilized to evaluate the heating value of POW. From the experimental results, it is found that higher heating value (HHV) varies with the moisture content (MC) and it is observed as a function of MC. (author)

  13. Whole-body fat oxidation determined by graded exercise and indirect calorimetry: a role for muscle oxidative capacity?

    DEFF Research Database (Denmark)

    Nordby, P; Saltin, B; Helge, J W

    2006-01-01

    During whole-body exercise, peak fat oxidation occurs at a moderate intensity. This study investigated whole-body peak fat oxidation in untrained and trained subjects, and the presence of a relation between skeletal muscle oxidative enzyme activity and whole-body peak fat oxidation. Healthy male...... from vastus lateralis and a 3 h bicycle exercise test was performed at 58% of VO(2max). Whole-body fat oxidation was calculated during prolonged and graded exercise from the respiratory exchange ratio using standard indirect calorimetry equations. Based on the graded exercise test, whole-body peak fat...

  14. In-situ probing of metallic glass formation and crystallization upon heating and cooling via fast differential scanning calorimetry

    Science.gov (United States)

    Pogatscher, S.; Uggowitzer, P. J.; Löffler, J. F.

    2014-06-01

    The crystallization of small-scale Au-based metallic glass samples was investigated by fast differential scanning calorimetry. Rapid cooling and heating makes possible in-situ probing of glass formation from the supercooled liquid state or direct transition from the glassy state to the equilibrium liquid and, thereby, the determination of a critical cooling (Φc ˜ 600 Ks-1) and heating rate (Φh ˜ 6 × 103 Ks-1) for crystallization. Crystallization kinetics was studied in the whole supercooled liquid region by linear heating and isothermal calorimetry. We show that the temperature dependence of crystal growth is reflected in a "Kissinger plot" for Au49Ag5.5Pd2.3Cu26.9Si16.3 and compares well with a model for crystal growth in a glassy system. Linear heating and isothermal measurements after heating the glass show that its crystallization is always growth-controlled up to its temperature of melting. In contrast, for a low degree of direct undercooling from the equilibrium liquid isothermal crystallization is nucleation-controlled, whereas it is again growth-controlled at large undercooling. The overall crystallization behavior of the metallic glass is presented in a complete time-temperature-transformation map on cooling and, so far not accessible, on heating after various cooling procedures.

  15. Evaluation of aluminosilicate glass sintering during differential scanning calorimetry; Estudo da sinterizacao de vidros aluminossilicatos por calorimetria exploratoria diferencial

    Energy Technology Data Exchange (ETDEWEB)

    Souza, Juliana Pereira de

    2015-07-01

    In this work a difference in the baseline in differential scanning calorimetry analyses, observed in a work where aluminosilicate glasses microspheres containing Ho were studied for application in selective internal radiotherapy as hepatocellular carcinoma treatment, was studied. The glasses with nominal composition 53,7 SiO{sub 2} .10,5 Al{sub 2}O{sub 3} . 35,8 MgO in %mol were produced from traditional melting. The first obtained were milled and sieved in the range of 45 a 63 μm. The material was used to produce glass microspheres by the gravitational fall method. The glass powder and the microspheres were characterized by X ray fluorescence spectrometry, laser diffraction, X ray diffraction, differential scanning calorimetry, differential thermal analysis, thermogravimetry, mass spectrometry, and scanning electron microscopy. After the thermal analyses, pellets were formed in the crucibles and were analyzed by scanning electron microscopy, X ray diffraction, and He pycnometry. The difference in the baseline was associated to the viscous flow sintering process and happens because of the decrease in the detected heat flow due to the sample shrinkage. Other events as concurrent crystallization with the sintering process were also studied. (author)

  16. Interactions in interesterified palm and palm kernel oils mixtures. II – Microscopy and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Grimaldi, Renato

    2001-12-01

    Full Text Available Palm oil (PO and palm kernel oil (PKO compositions (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 and 0/100 were interesterified in laboratory scale under predetermined conditions (0.4% sodium metoxide, 20 minutes, 100ºC. The fourteen samples, before and after interesterification, were characterized by Polarized Light Microscopy and Differential Scanning Calorimetry (DSC. Results showed the effect of various factors on the form and width of crystals. The mean area of crystals revealed the increase of crystals when PKO was added, with values varying from 2.7 x 10E3 µm2 to PO and 1.8 x 10E6 µm2 to PKO. After interesterification, the crystal widths were lower at PO/PKO 100/0, 80/20, 60/40, 20/80 fractions and were higher to anothers. The beta-prime polimorphic form was observed in the pure palm oil sample. The results showed in melting curves, onset values from –19.6ºC to more unsaturated peaks until 20.7ºC to more saturated ones. The higher values to more saturated peak in a melting curve to palm oil, 38.7 J.g-1 before and 48.4 J.g-1 after interesterification, showed a mores table saturated group. I n a genera l way, t h e interesterification promoted an increase of crystallization rate and a better compatibility between PO/PKO fractions.Fueron interesterificados en el laboratorio mezclas de aceite de palma (PO y aceite de palmiste (PKO en diferentes proporciones (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 y 0/100 bajo condiciones predeterminadas (0.4% metoxido de sodio, 20 minutos, 100ºC. Las catorce muestras fueron caracterizadas antes y después de la interesterificación por Microscopía de Luz Polarizada y por Calorimetría Diferencial de Barrido (DSC. Los resultados mostraron el efecto de varios factores sobre la forma y anchura de los cristales. El área media de los cristales revela el aumento de tamaño de los mismos cuando aumenta la proporción de PKO, con valores que varían entre 2.7 x 10E3 µm2 para PO y 1.8 x 10E

  17. Change in physical structure of a phenol-spiked sapric histosol observed by Differential Scanning Calorimetry

    Science.gov (United States)

    Ondruch, Pavel; Kucerik, Jiri; Schaumann, Gabriele E.

    2014-05-01

    Interactions of pollutants with soil organic matter (SOM), their fate and transformation are crucial for understanding of soil functions and properties. In past, many papers dealing with sorption of organic and inorganic compounds have been published. However, their aim was almost exceptionally fo-cused on the pollutants themselves, determination of sorption isotherms and influence of external factors, while the change in SOM supramolecular structure was usually ignored. The SOM structure is, however, very important, since the adsorbed pollutant might have a significant influence on soil stability and functions. Differential scanning calorimetry (DSC) represents a technique, which has been successfully used to analyze the physical structure and physico-chemical aging of SOM. It has been found out that water molecules progressively stabilize SOM (water molecule bridge (WaMB)) (Schaumann & Bertmer 2008). Those bridges connect and stabilize SOM and can be disrupted at higher temperature (WaMB transition; (Kunhi Mouvenchery et al. 2013; Schaumann et al. 2013). In the same temperature region melting of aliphatic moieties can be observed (Hu et al. 2000; Chilom & Rice 2005; Kucerik et al. submitted 2013). In this work, we studied the effect of phenol on the physical structure of sapric histosol. Phenol was dissolved in various solvents (water, acetone, hexane, methanol) and added to soils. After the evaporation of solvents by air drying, the sample was equilibrated at 76% relative humidity for 3 weeks. Using DSC, we investigated the influence of phenol on histosol structure and time dependence of melting temperature of aliphatic moieties and WaMB transition. While addition of pure organic solvent only resulted in slightly increased transition temperatures, both melting temperature and WaMB transition temperature were significantly reduced in most cases if phenol was dissolved in these solvents. Water treatment caused a decrease in WaMB transition temperature but

  18. PREFACE: XIII International Conference on Calorimetry in High Energy Physics (CALOR 2008)

    Science.gov (United States)

    Livan, Michele

    2009-07-01

    The XIII International Conference on Calorimetry in High Energy Physics was held in Pavia, Italy, 26-30 May 2008, picking up the baton from the 2006 Conference in Chicago. The Conference took place in the unique environment of the Theresian Room of the University Library. The attendees were surrounded by over 40 000 books of general interest and culture, and had the opportunity to see precious volumes written by such people as Galileo, Volta and Faraday. The Workshop brought together more than 120 participants, including senior scientists as well as young physicists, confirming the central and ever-growing role of calorimeters in modern particle physics. The development of these detectors, as stressed by Professor Klaus Pretzl in his lectio magistralis, has made it possible to explore new frontiers in physics, and the present scenario is no exception to this rule. With the LHC experiments almost completely installed and ready to take data, the Conference was an ideal chance to review the status of the different projects, whose development has been followed and discussed throughout the entire Calor series, and to show that they are capable of meeting the design specifications. Other highlights were the performance and physics results of calorimeters installed in currently operating experiments. In the session on astrophysics and neutrinos, the contributions confirmed the key role of calorimeters in this sector and demonstrated their growing application even beyond the field of accelerator physics. Considerable time was devoted to the state-of-the-art techniques in the design and operation of the detectors, while the session on simulation addressed the importance of a thorough understanding of the shower development to meet the demanding requirements of present experiments. Finally, on the R&D side, the particle flow and dual read-out concepts confronted the challenges issued by the next generation of experiments. This complex material was reviewed in 83

  19. Effect of L-Carnitine in Patients With Liver Cirrhosis on Energy Metabolism Using Indirect Calorimetry: A Pilot Study

    Science.gov (United States)

    Sakai, Yoshiyuki; Nishikawa, Hiroki; Enomoto, Hirayuki; Yoh, Kazunori; Iwata, Yoshinori; Hasegawa, Kunihiro; Nakano, Chikage; Kishino, Kyohei; Shimono, Yoshihiro; Takata, Ryo; Nishimura, Takashi; Aizawa, Nobuhiro; Ikeda, Naoto; Takashima, Tomoyuki; Ishii, Akio; Iijima, Hiroko; Nishiguchi, Shuhei

    2016-01-01

    Background L-carnitine supplementation has been suggested to show several favorable effects on patients with liver cirrhosis (LC). However, there have been no reports regarding the effect of L-carnitine on energy metabolism in patients with LC using indirect calorimetry which is a well-established method for assessing the degree of liver malnutrition. We examined the effect of L-carnitine in patients with LC on energy metabolism using indirect calorimetry. Methods A total of 13 LC patients who are scheduled to be treated with L-carnitine (1,800 mg/day) were analyzed in this study. None of the patients previously received L-carnitine. An evaluation of the nutritional status was performed at the initiation of L-carnitine therapy and after 4 weeks of L-carnitine therapy. We evaluated the effect of L-carnitine on the nutritional status and energy metabolism by comparing various clinical variables at these two time points. In addition, the changes in the nutritional status of the patients were also evaluated using indirect calorimetry. Results After 4 weeks of L-carnitine treatment, for all cases, the mean substrate oxidation rates of carbohydrate (%C) increased from 37.6% to 48.2%, the mean substrate oxidation rates of fat (%F) decreased from 40.2% to 31.9% and the mean substrate oxidation rates of protein (%P) decreased from 22.2% to 19.9%. In a subgroup analysis of patients with baseline non-protein respiratory quotient (npRQ) L-carnitine treatment, for all cases (n = 13), the mean value of npRQ increased in comparison with the baseline levels, although the difference was not significant (0.868 ± 0.060 vs. 0.838 ± 0.097, P = 0.19). Conversely, in patients with baseline npRQ L-carnitine compared with the baseline levels (0.827 ± 0.030 vs. 0.760 ± 0.043, P = 0.016). Conclusion L-carnitine supplementation can be useful for improving energy metabolism, especially in patients who have an advanced LC status and lower baseline npRQ values. PMID:27829952

  20. The use of isothermal titration calorimetry to assess the solubility enhancement of simvastatin by a range of surfactants

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Rajesh [School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom); Buckton, Graham [School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)]. E-mail: graham.buckton@pharmacy.ac.uk; Gaisford, Simon [School of Pharmacy, University of London, 29-39 Brunswick Square, London WC1N 1AX (United Kingdom)

    2007-05-15

    Surfactants are commonly used to increase the solubility of poorly water soluble drugs but the interactions between drug and surfactant can be complex and quantitative relationships can be hard to derive. One approach is to quantify the thermodynamics of interaction and relate these parameters to known solubility or dissolution rate enhancement data. Isothermal titration calorimetry (ITC) was used to measure the enthalpy and free energy of transfer of a model drug (simvastatin) to a number of surfactant (SDS, HTAB, SDCH and Brij 35) micelles. These data were then compared with the solubility enhancements determined for each surfactant using HPLC assays. As expected, there was correlation between the free energy of transfer for the drug to each surfactant and the solubility enhancement of that surfactant. Although the data set is limited, the results suggest that ITC screening of a range of surfactants against a poorly water soluble drug may allow the selection of the best potential solubilising surfactants.

  1. Accelerating rate calorimetry study on the thermal stability of interpenetrating network type poly(siloxane-g-ethylene oxide) polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Bookeun; Hyung, Yoo-Eup; Vissers, Donald R.; Amine, Khalil

    2003-06-30

    Safety study regarding an exothermic reaction at elevated temperature of comb-shaped siloxane polymer and its interpenetrating network type solid polymer electrolyte (SPE) are investigated. Accelerating rate calorimetry (ARC) is used to examine exothermic reactions. The thermal stability of the polymer electrolyte in the presence of charged electrodes is also monitored. Resulting data were compared with those of 1.0 M LiPF{sub 6} in ethylene carbonate:ethyl methyl carbonate (3:7 by wt.) electrolyte. The self-heating exothermic reaction of mono comb-shaped siloxane polymer electrolyte starts at approximately 300 deg. C. Comparison of the heat generation profiles from ARC tests indicates that SPE reduces the intensity of exothermic reactions resulting from charged electrodes and electrolyte.

  2. Probing volumetric properties of biomolecular systems by pressure perturbation calorimetry (PPC)--the effects of hydration, cosolvents and crowding.

    Science.gov (United States)

    Suladze, Saba; Kahse, Marie; Erwin, Nelli; Tomazic, Daniel; Winter, Roland

    2015-04-01

    Pressure perturbation calorimetry (PPC) is an efficient technique to study the volumetric properties of biomolecules in solution. In PPC, the coefficient of thermal expansion of the partial volume of the biomolecule is deduced from the heat consumed or produced after small isothermal pressure-jumps. The expansion coefficient strongly depends on the interaction of the biomolecule with the solvent or cosolvent as well as on its packing and internal dynamic properties. This technique, complemented with molecular acoustics and densimetry, provides valuable insights into the basic thermodynamic properties of solvation and volume effects accompanying interactions, reactions and phase transitions of biomolecular systems. After outlining the principles of the technique, we present representative examples on protein folding, including effects of cosolvents and crowding, together with a discussion of the interpretation, and further applications. Copyright © 2014 Elsevier Inc. All rights reserved.

  3. Specific heat of Zr-2.5Nb pressure tube material measured by differential scanning calorimetry (DSC)

    Energy Technology Data Exchange (ETDEWEB)

    Fong, R.W.L.; Neal, P.D. [Canadian Nuclear Laboratories, Chalk River, ON (Canada); Fazeli, F.; Aniolek, M. [CanmetMATERIALS, Hamilton, ON (Canada); Gezgin, S. [NETZSCH-Geratebau GmbH, Wittelsbacherstr, Selb/Bavaria (Germany)

    2015-07-01

    Specific heats of Zr-2.5Nb pressure tube material have been measured by differential scanning calorimetry (DSC) between 100{sup o}C and 1200{sup c}C using a heating and cooling rate of 20{sup o}C/min. A hysteresis was observed in the specific heat curves between heating and cooling. A maximum value occurs at a higher temperature on heating than on cooling, and the magnitude is larger for cooling when compared to heating. The as-manufactured tube material showed a small enthalpy change during first heating, attributed to decomposition of meta-stable β-Zr; and this did not appear on second heating after being first heated to 1200{sup o}C. Further studies are suggested to characterize the hysteresis behaviour. (author)

  4. Interaction of phenazinium dyes with double-stranded poly(A): spectroscopy and isothermal titration calorimetry studies.

    Science.gov (United States)

    Khan, Asma Yasmeen; Saha, Baishakhi; Kumar, Gopinatha Suresh

    2014-10-15

    A comprehensive study on the binding of phenazinium dyes viz. janus green B, indoine blue, safranine O and phenosafranine with double stranded poly(A) using various spectroscopic and calorimetric techniques is presented. A higher binding of janus green B and indoine blue over safranine O and phenosafranine to poly(A) was observed from all experiments. Intercalative mode of binding of the dyes was inferred from fluorescence polarization anisotropy, iodide quenching and viscosity experiments. Circular dichroism study revealed significant perturbation of the secondary structure of poly(A) on binding of these dyes. Results from isothermal titration calorimetry experiments suggested that the binding was predominantly entropy driven with a minor contribution of enthalpy to the standard molar Gibbs energy. The results presented here may open new opportunities in the application of these dyes as RNA targeted therapeutic agents. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Synergetic Determination of Thermodynamic and Kinetic Signatures Using Isothermal Titration Calorimetry: A Full-Curve-Fitting Approach.

    Science.gov (United States)

    Li, Dexing; Chen, Lan; Wang, Ruimin; Liu, Renxiao; Ge, Guanglu

    2017-07-05

    Thermodynamic and kinetic signatures are pivotal information for revealing the binding mechanisms of biomolecules, and they play an indispensable role in drug discovery and optimization. While noncalorimetric methods measure only a part of these signatures, isothermal titration calorimetry (ITC) is considered to have the potential to acquire full signatures in an experiment. However, kinetic parameters are generally difficult to extract from ITC curves, as they are inevitably affected by the instrument-response function and the collateral heat of associated process during titrations. Thus, we herein report the development and validation of a full-curve-fitting method to resolve thermal power curves and to maximize the signal extraction using ITC. This method is then employed to quantify the dilution of an aqueous n-propanol solution and examine the inhibition of carbonic anhydrase by 4-carboxybenzenesulfonamide using a commercial instrument with a long apparent response time of ∼13 s.

  6. Combination of isothermal titration calorimetry and time-resolved luminescence for high affinity antibody-ligand interaction thermodynamics and kinetics

    Science.gov (United States)

    Aweda, Tolulope A.; Meares, Claude F.

    2011-01-01

    For experiments using synthetic ligands as probes for biological experiments, it is useful to determine the specificity and affinity of the ligands for their receptors. As ligands with higher affinities are developed (KA >108 M−1; KD titration calorimetry measures heat produced or consumed during ligand binding, and also provides the equilibrium binding constant. However, as normally practiced, its range is limited. Displacement titration, where a competing weaker ligand is used to lower the apparent affinity of the stronger ligand, can be used to determine the binding affinity as well as the complete thermodynamic data for ligand-antibody complexes with very high affinity. These equilibrium data have been combined with kinetic measurements to yield the rate constants as well. We describe this methodology, using as an example antibody 2D12.5, which captures yttrium S-2-(4-aminobenzyl)-1, 4, 7, 10-tetraazacyclododecanetetraacetate. PMID:21964396

  7. Chemometric processing of pharmaceutical essential oil fingerprints -- comparison of GC, HPLC, TLC, IR spectroscopy, and differential scanning calorimetry.

    Science.gov (United States)

    Pietraś, Rafal; Skibiński, Robert; Trebacz, Hanna; Gumieniczek, Anna

    2012-01-01

    Fifteen essential oils of pharmaceutical grade were fingerprinted by five techniques: TLC, GC, HPLC, attenuated total reflectance FTIR spectroscopy, and differential scanning calorimetry (DSC). Denoising and baseline removal was found to be a crucial step for correct comparative analysis. Standardization of the signal was not necessary in the presented case; however, it should be considered and checked in each case. Due to small variance explained by first two principal components (below 50%) and outlying observations, the main analysis was performed by Euclidean dendrograms. It was found that almost all techniques besides DSC find real chemical similarities; however, DSC can be used as an additional tool. The similarities among the five techniques were also compared and discussed.

  8. Effects of 2 wk of GH administration on 24-h indirect calorimetry in young, healthy, lean men

    DEFF Research Database (Denmark)

    Hansen, Mette; Morthorst, Rikke; Larsson, Benny

    2005-01-01

    The present study was designed as a randomized, double-blind placebo (Plc)-controlled study to determine the effect of 2 wk of growth hormone administration (GH-adm.) on energy expenditure (EE) and substrate oxidation in healthy humans. Sixteen young healthy men were divided into two groups....... The study consisted of two 24-h measurements (indirect calorimetry), separated by 2 wk of either Plc or GH injections (6 IU/day). At baseline, no significant differences were observed between the two groups in any of the measured anthropometric, hormonal, or metabolic parameters, neither did the parameters...... change over time in the Plc group. GH-adm. resulted in a 4.4% increase in 24-h EE (P

  9. Simultaneous differential scanning calorimetry and thermal desorption spectroscopy measurements for the study of the decomposition of metal hydrides

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez, J.F.; Cuevas, F.; Sanchez, C. [Univ. Autonoma, Madrid (Spain). Dept de Fisica de Materiales C-IV

    2000-02-28

    An innovative experimental method to investigate the thermal decomposition of metal hydrides is presented. The method is based on an experimental setup composed of a differential scanning calorimeter connected through a capillary tube to a mass spectrometer. The experimental system allows the simultaneous determination of the heat absorbed and the hydrogen evolved from a metal hydride during thermal decomposition. This arrangement constitutes a coupled differential scanning calorimetry (DSC) and thermal desorption spectroscopy (TDS) technique. It has been applied to metal hydride materials to demonstrate the capability of the experimental system. A method to obtain the heat of decomposition of metal hydrides is described. It involves the measurement of an apparent decomposition heat as a function of the carrier gas flow. (orig.)

  10. Crystal growth kinetics of ultra-thin ZrO2 film on Si by differential scanning calorimetry

    Science.gov (United States)

    Faruque, Sk Abdul Kader Md; Debnath, Debika; Giri, Bimalesh; Chakraborty, Supratic

    2017-02-01

    Crystal growth kinetics of thin ZrO2 film deposited on Si is described in the framework of Johnson, Mehl and Avrami (JMA) equation and Kissinger method. Differential scanning calorimetry is employed here to determine the Avrami exponent and the activation energy of crystalline transition from the amorphous nature of ZrO2/Si. The activation energy is found to be 0.77 ± 0.06 eV, estimated from the slope of Kissinger plot. From the variation of Avrami exponent, it is observed that the crystallization of ZrO2 begins at the ZrO2/Si interface and grows normal to the interface at lower temperature range. The crystallization grows laterally, identified as heterogeneous nucleation at the grain boundary that dominates at higher temperature range indicating an increase in its grain size without increasing the number of grains. Only the growth along the grain boundary occurs during heterogeneous crystallization.

  11. Binding between bixin and whey protein at pH 7.4 studied by spectroscopy and isothermal titration calorimetry.

    Science.gov (United States)

    Zhang, Yue; Zhong, Qixin

    2012-02-22

    Bixin is the major coloring component of annatto used in manufacturing colored cheeses, but its presence in liquid whey causes undesirable quality of the recovered whey protein ingredients. The objective of this work was to study molecular binding between bixin and three major whey proteins (β-lactoglobulin, α-lactalbumin, and bovine serum albumin) at pH 7.4 using UV-vis absorption spectroscopy, fluorescence spectroscopy, isothermal titration calorimetry, and circular dichroism. These complementary techniques illustrated that the binding is a spontaneous complexation process mainly driven by hydrophobic interactions. The complexation is favored at a lower temperature and a higher ionic strength. At a lower temperature, the binding is entropy-driven, while it changes to an enthalpy-driven process at higher temperatures. The binding also increases the percentage of unordered secondary structures of proteins. Findings from this work can be used to develop whey protein recovery processes for minimizing residual annatto content in whey protein ingredients.

  12. Direct technique for monitoring lipid oxidation in water-in-oil emulsions based on micro-calorimetry.

    Science.gov (United States)

    Dridi, Wafa; Toutain, Jean; Sommier, Alain; Essafi, Wafa; Leal-Calderon, Fernando; Cansell, Maud

    2017-09-01

    An experimental device based on the measurement of the heat flux dissipated during chemical reactions, previously validated for monitoring lipid oxidation in plant oils, was extended to follow lipid oxidation in water-in-oil emulsions. Firstly, validation of the approach was performed by correlating conjugated diene concentrations measured by spectrophotometry and the heat flux dissipated by oxidation reactions and measured directly in water-in-oil emulsions, in isothermal conditions at 60°C. Secondly, several emulsions based on plant oils differing in their n-3 fatty acid content were compared. The oxidability parameter derived from the enthalpy curves reflected the α-linolenic acid proportion in the oils. On the whole, the micro-calorimetry technique provides a sensitive method to assess lipid oxidation in water-in-oil emulsions without requiring any phase extraction. Copyright © 2017 Elsevier Ltd. All rights reserved.

  13. Influence of frost damage and sample preconditioning on the porosity characterization of cement based materials using low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Fridh, Katja; Johannesson, Björn

    2015-01-01

    Low temperature calorimetry (LTC) can be used to study the meso-porosity of cement based materials. The influence of frost damage on the meso-porosity determination by LTC was explored on a model material MCM-41 and two cement pastes by conducting repeated cycles of freezing and melting...... the preconditioning has limited influence on the freezing and melting behavior of the pore solution in the studied cement paste samples....... measurements. The results indicate that the pressure generated during freezing and melting measurements has little impact on the pore structure of the powder MCM-41 samples. As for the studied cylinder samples of cement pastes, frost damage probably took place and it changed the pore connectivity while it had...

  14. SU-D-BRC-06: Experimental and Monte Carlo Studies of Fluence Corrections for Graphite Calorimetry in Proton Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Lourenco, A [University College London, London (United Kingdom); National Physical Laboratory, Teddington (United Kingdom); Thomas, R [National Physical Laboratory, Teddington (United Kingdom); Bouchard, H [University of Montreal, Montreal (Canada); Kacperek, A [National Eye Proton therapy Centre, Clatterbridge Cancer Centre, Wirral (United Kingdom); Vondracek, V [Proton Therapy Center, Prague (Czech Republic); Royle, G [University College London, London (United Kingdom); Palmans, H [National Physical Laboratory, Teddington (United Kingdom); EBG MedAustron GmbH, Wiener Neustadt (Austria)

    2016-06-15

    Purpose: For photon and electron beams, the standard device used to measure absorbed dose is a calorimeter. Standards laboratories are currently working on the establishment of graphite calorimeters as a primary standard for proton beams. To provide a practical method for graphite calorimetry, it is necessary to convert dose to graphite to dose to water, requiring knowledge of the water-to-graphite stopping-power ratio and the fluence correction factor. This study aims to present a novel method to determine fluence corrections experimentally, and to apply this methodology to low- and high-energy proton beams. Methods: Measurements were performed in 60 MeV and 180 MeV proton beams. Experimental information was obtained from depth-dose ionization chamber measurements performed in a water phantom. This was repeated with different thicknesses of graphite plates in front of the water phantom. One distinct advantage of this method is that only ionization chamber perturbation factors for water are required. Fluence corrections were also obtained through Monte Carlo simulations for comparison with the experiments. Results: The experimental observations made in this study confirm the Monte Carlo results. Overall, fluence corrections between water and graphite increased with depth, with a maximum correction of 1% for the low-energy beam and 4% for the high-energy beam. The results also showed that a fraction of the secondary particles generated in proton therapy beams do not have enough energy to cross the ionization chamber wall; thus, their contribution is not accounted for in the measured fluence corrections. This effect shows up as a discrepancy in fluence corrections of 1% and has been confirmed by simulations of the experimental setup. Conclusion: Fluence corrections derived by experiment do not account for low-energy secondary particles that are stopped in the ion chamber wall. This work will contribute to a practical graphite calorimetry technique for determining

  15. Particle Size (Sieving) and Enthalpy (Acid Calorimetry) Analysis of Single-Pull K East Basin Floor and Pit Sludges

    Energy Technology Data Exchange (ETDEWEB)

    PR Bredt; CH Delegard; AJ Schmidt; KL Silvers; BM Thornton; S Gano

    2000-12-22

    This report presents the results of particle size analyses and calorimetry testing performed on selected single-pull sludge samples collected from the Hanford K East Basin between December 1998 and June 1999. The samples were collected as isolated cores predominantly from areas that had not been previously sampled (e.g., North Loadout Pit, Dummy Elevator Pit, Tech View Pit), or from areas in which the sludge composition had been altered since the last sampling (e.g., Weasel Pit). Particle size analyses were performed by washing wet sludge samples through a series of four sieves with openings of 250, 500, 1410, and 4000 {micro}m. The loaded sieves were weighed before and after drying to obtain wet and dry particle size distributions. Knowledge of the particle size distribution is needed to design and predict the performance of the systems that will be used to retrieve, transport, and recover sludge. Also, sieving provides an opportunity to observe the components in the sludge. For example, during sieving of the sludge sample from the North Loadout Pit, significant quantities of organic ion exchange beads were observed. The uranium metal content and the particle size of the uranium metal in the K Basin sludge will largely determine the chemical reactivity of the sludge. In turn, the designs for the sludge handling and storage systems must be compatible with the reactivity of the sludge. Therefore, acid calorimetry was performed to estimate the uranium metal content of the sludge. For this testing, sludge samples were dissolved in nitric acid within a calibrated adiabatic calorimeter. The resulting dissolution enthalpy data were then used to discriminate between metallic uranium ({minus}3750 J/g in nitric acid) and uranium oxide ({minus}394 J/g in nitric acid). Results from this testing showed that the single-pull sludge samples contained little or no uranium metal.

  16. Estimation of activity related energy expenditure and resting metabolic rate in freely moving mice from indirect calorimetry data.

    Directory of Open Access Journals (Sweden)

    Jan Bert Van Klinken

    Full Text Available Physical activity (PA is a main determinant of total energy expenditure (TEE and has been suggested to play a key role in body weight regulation. However, thus far it has been challenging to determine what part of the expended energy is due to activity in freely moving subjects. We developed a computational method to estimate activity related energy expenditure (AEE and resting metabolic rate (RMR in mice from activity and indirect calorimetry data. The method is based on penalised spline regression and takes the time dependency of the RMR into account. In addition, estimates of AEE and RMR are corrected for the regression dilution bias that results from inaccurate PA measurements. We evaluated the performance of our method based on 500 simulated metabolic chamber datasets and compared it to that of conventional methods. It was found that for a sample time of 10 minutes the penalised spline model estimated the time-dependent RMR with 1.7 times higher accuracy than the Kalman filter and with 2.7 times higher accuracy than linear regression. We assessed the applicability of our method on experimental data in a case study involving high fat diet fed male and female C57Bl/6J mice. We found that TEE in male mice was higher due to a difference in RMR while AEE levels were similar in both groups, even though female mice were more active. Interestingly, the higher activity did not result in a difference in AEE because female mice had a lower caloric cost of activity, which was likely due to their lower body weight. In conclusion, TEE decomposition by means of penalised spline regression provides robust estimates of the time-dependent AEE and RMR and can be applied to data generated with generic metabolic chamber and indirect calorimetry set-ups.

  17. Combined use of titration calorimetry and spectrofluorimetry for the screening of the acidity of solid catalysts in different liquids

    Energy Technology Data Exchange (ETDEWEB)

    Gervasini, Antonella, E-mail: antonella.gervasini@unimi.it [Dipartimento di Chimica, Università degli Studi di Milano, via Camillo Golgi, 19, 20133 Milano (Italy); Auroux, Aline, E-mail: aline.auroux@ircelyon.univ-lyon1.fr [Université Lyon 1, CNRS, UMR 5256, Institut de Recherches sur la Catalyse et l‘Environnement de Lyon (IRCELYON), 2 Avenue A. Einstein, 69626 Villeurbanne (France)

    2013-09-10

    Graphical abstract: Measurements of acidity of oxides of catalytic importance in various liquids open the possibility to know their effective acidity, which is related with their activity in liquid-heterogeneous catalysis. Titration-calorimetry alone or in connection with spectrofluorimetry is efficient for this scope. - Highlights: • Measurements of acidity of oxides of catalytic importance in various liquids. • Titration-calorimetry alone or in connection with spectrofluorimetry is efficient for this scope. • Effective acidities are expressed by given sample in various liquids. • Nb-containing samples are able to maintain acidity in protic liquids. - Abstract: The effective acid and base surface properties of selected acidic and basic samples of catalytic interest (alumina, titania, zirconia, silica–alumina, niobium oxide, niobium phosphate, boron nitride, and hydrotalcite) were measured by titration with basic and acidic molecular probes (aniline, 2-phenylethylamine, and phenol) in various liquids (cyclohexane, 1,4-dioxane, isopropanol, n-decane, and toluene) with different polar and protic characteristics. The combined use of a reaction calorimeter and a spectrofluorimeter has been performed. The set-up of the coupled technique and the most interesting results are shown here. The study confirmed that the acid–base properties of solids are deeply affected by the nature and properties of the liquid surrounding the samples. Few oxides are able to maintain their surface acidity in highly polar and protic solvents, in particular whose containing niobium. In general, the solvating and coordinative ability of the most polar and protic liquids caused remarkable loss of acidity/basicity of the oxide surfaces.

  18. A novel method for determining the solubility of small molecules in aqueous media and polymer solvent systems using solution calorimetry.

    Science.gov (United States)

    Fadda, Hala M; Chen, Xin; Aburub, Aktham; Mishra, Dinesh; Pinal, Rodolfo

    2014-07-01

    To explore the application of solution calorimetry for measuring drug solubility in experimentally challenging situations while providing additional information on the physical properties of the solute material. A semi-adiabatic solution calorimeter was used to measure the heat of dissolution of prednisolone and chlorpropamide in aqueous solvents and of griseofulvin and ritonavir in viscous solutions containing polyvinylpyrrolidone and N-ethylpyrrolidone. Dissolution end point was clearly ascertained when heat generation stopped. The heat of solution was a linear function of dissolved mass for all drugs (solution of 9.8 ± 0.8, 28.8 ± 0.6, 45.7 ± 1.6 and 159.8 ± 20.1 J/g were obtained for griseofulvin, ritonavir, prednisolone and chlorpropamide, respectively. Saturation was identifiable by a plateau in the heat signal and the crossing of the two linear segments corresponds to the solubility limit. The solubilities of prednisolone and chlopropamide in water by the calorimetric method were 0.23 and 0.158 mg/mL, respectively, in agreement with the shake-flask/HPLC-UV determined values of 0.212 ± 0.013 and 0.169 ± 0.015 mg/mL, respectively. For the higher solubility and high viscosity systems of griseofulvin and ritonavir in NEP/PVP mixtures, respectively, solubility values of 65 and 594 mg/g, respectively, were obtained. Solution calorimetry offers a reliable method for measuring drug solubility in organic and aqueous solvents. The approach is complementary to the traditional shake-flask method, providing information on the solid properties of the solute. For highly viscous solutions, the calorimetric approach is advantageous.

  19. "Greening" a Familiar General Chemistry Experiment: Coffee Cup Calorimetry to Determine the Enthalpy of Neutralization of an Acid-Base Reaction and the Specific Heat Capacity of Metals

    Science.gov (United States)

    Bopegedera, A. M. R. P.; Perera, K. Nishanthi R.

    2017-01-01

    Coffee cup calorimetry, performed with calorimeters made with styrofoam coffee cups, is a familiar experiment in the general chemistry laboratory. These calorimeters are inexpensive, easy to use, and provide good insulation for most thermodynamics experiments. This paper presents the successful substitution of paper coffee cups for styrofoam cups…

  20. Characterization of the molecular distribution of drugs in glassy solid dispersions at the nano-meter scale, using differential scanning calorimetry and gravimetric water vapour sorption techniques

    NARCIS (Netherlands)

    van Drooge, D J; Hinrichs, W L J; Visser, M R; Frijlink, H W

    2006-01-01

    The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T-g), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam

  1. A study of the growth for the microalga Chlorella vulgaris by photo-bio-calorimetry and other on-line and off-line techniques

    NARCIS (Netherlands)

    Patino, R.; Janssen, M.G.J.; Stockar, von U.

    2007-01-01

    Calorimetry and other on-line techniques are used for the first time as complement to the traditional off-line methods in order to follow the growth of the green Chlorella vulgaris microalgae. A 2-L photo-bio-reactor was adapted from a commercial calorimeter used previously to study heterotrophic

  2. Understanding binding affinity : A combined isothermal titration calorimetry/molecular dynamics study of the binding of a series of hydrophobically modified benzamidinium chloride inhibitors to trypsin

    NARCIS (Netherlands)

    Talhout, Reinskje; Villa, Alessandra; Mark, AE; Engberts, JBFN

    2003-01-01

    The binding of a series of p-alkylbenzamidinium chloride inhibitors to the serine proteinase trypsin over a range of temperatures has been studied using isothermal titration (micro)calorimetry and molecular dynamics simulation techniques. The inhibitors have small structural variations at the para

  3. Low validity of the Sensewear Pro3 activity monitor compared to indirect calorimetry during simulated free living in patients with osteoarthritis of the hip

    DEFF Research Database (Denmark)

    Hermann, Andreas; Ried-Larsen, Mathias; Jensen, Andreas Emil Kryger

    2014-01-01

    BACKGROUND: To validate physical activity estimates by the Sensewear Pro3 activity monitor compared with indirect calorimetry during simulated free living in patients diagnosed with osteoarthritis of the hip pre or post total hip arthroplasty. METHODS: Twenty patients diagnosed with hip osteoarth...

  4. Optimization of the scintillation parameters of the lead tungstate crystals for their application in high precision electromagnetic calorimetry; Optimisation des parametres de scintillation des cristaux de tungstate de plomb pour leur application dans la calorimetrie electromagnetique de haute precision

    Energy Technology Data Exchange (ETDEWEB)

    Drobychev, G

    2000-04-12

    In the frame of this dissertation work scintillation properties of the lead tungstate crystals (PWO) and possibilities of their use were studied foreseeing their application for electromagnetic calorimetry in extreme radiation environment conditions of new colliders. The results of this work can be summarized in the following way. 1. A model of the scintillations origin in the lead tungstate crystals which includes processes influencing on the crystals radiation hardness and presence of slow components in scintillations was developed. 2. An analysis of the influences of the PWO scintillation properties changes on the parameters of the electromagnetic calorimeter was done. 3. Methods of the light collection from the large scintillation elements of complex shape made of the birefringent scintillation crystal with high refraction index and low light yield in case of signal registration by a photodetector with sensitive surface small in compare with the output face of scintillator were Studied. 4. Physical principles of the methodology of the scintillation crystals certification during their mass production foreseeing their installation into a calorimeter electromagnetic were developed. Correlations between the results of measurements of the PWO crystals parameters by different methods were found. (author)

  5. Weak interactions in clobazam-lactose mixtures examined by differential scanning calorimetry: Comparison with the captopril-lactose system

    Energy Technology Data Exchange (ETDEWEB)

    Toscani, S. [Departement de Chimie - UMR 6226, Faculte des Sciences, Universite de Rennes 1, Batiment 10B, 263 avenue du General Leclerc, F-35042 Rennes Cedex (France); Cornevin, L. [Universite de Rennes 1, Faculte de Pharmacie, 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); Burgot, G., E-mail: Gwenola.burgot@univ-rennes1.fr [Universite de Rennes 1, Faculte de Pharmacie, Laboratoire de Chimie Analytique, EA 1274 ' Mouvement, sports, sante' , 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); CHGR Rennes, Pole Medico-Technique Pharmacie, F-35703 Rennes Cedex (France)

    2012-09-10

    Highlights: Black-Right-Pointing-Pointer Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. Black-Right-Pointing-Pointer Energy-barrier decrease for lactose dehydration induced by clobazam. Black-Right-Pointing-Pointer Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. Black-Right-Pointing-Pointer Decrease of lactose dehydration temperature in binary mixtures with captopril. Black-Right-Pointing-Pointer Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous {alpha}-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril-lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.

  6. Modeling complex equilibria in isothermal titration calorimetry experiments: thermodynamic parameters estimation for a three-binding-site model.

    Science.gov (United States)

    Le, Vu H; Buscaglia, Robert; Chaires, Jonathan B; Lewis, Edwin A

    2013-03-15

    Isothermal titration calorimetry (ITC) is a powerful technique that can be used to estimate a complete set of thermodynamic parameters (e.g., K(eq) (or ΔG), ΔH, ΔS, and n) for a ligand-binding interaction described by a thermodynamic model. Thermodynamic models are constructed by combining equilibrium constant, mass balance, and charge balance equations for the system under study. Commercial ITC instruments are supplied with software that includes a number of simple interaction models, for example, one binding site, two binding sites, sequential sites, and n-independent binding sites. More complex models, for example, three or more binding sites, one site with multiple binding mechanisms, linked equilibria, or equilibria involving macromolecular conformational selection through ligand binding, need to be developed on a case-by-case basis by the ITC user. In this paper we provide an algorithm (and a link to our MATLAB program) for the nonlinear regression analysis of a multiple-binding-site model with up to four overlapping binding equilibria. Error analysis demonstrates that fitting ITC data for multiple parameters (e.g., up to nine parameters in the three-binding-site model) yields thermodynamic parameters with acceptable accuracy. Copyright © 2012 Elsevier Inc. All rights reserved.

  7. Interaction of insulin, cholesterol-derivatized mannan, and carboxymethyl chitin with liposomes: A differential scanning calorimetry study.

    Science.gov (United States)

    Tabbakhian, M; Rogers, J A

    2012-01-01

    The interaction of drugs and polymers used to incorporate in or surface modify/coat the liposomes can affect the phase transition, fluidity and other physical properties as well as in vivo fate of vesicles. In this study, differential scanning calorimetry (DSC) was used to investigate changes in the temperature and the enthalpy of phase transition of liposomes of various electrical charges following interaction with carboxymethyl chitin (CM-chitin) as a hydrophilic polymer, cholesterol-derivatized mannan (CHM) as a hydrophilic polymer bearing a hydrophobic moiety, and insulin as a model peptide. The results indicated that insulin incorporation or polymers caused no significant change in the phase transition temperature (T(m)) of liposomes. However, reduction in the enthalpy of the transition (ΔH°) following coating with CHM supports an anchoring mechanism to the bilayer by the polymer, whereas no change or little increase in the ΔH° after coating with carboxymethyl chitin suggests no significant interaction or electrostatic weak interactions of polymer with liposomes. The DSC data of liposome-polymer interaction may be suggestive of changes in membrane fluidity, drug release, and possibly the behavior of liposomes in biological milieu.

  8. Mathematical Model for Localised and Surface Heat Flux of the Human Body Obtained from Measurements Performed with a Calorimetry Minisensor.

    Science.gov (United States)

    Socorro, Fabiola; Rodríguez de Rivera, Pedro Jesús; Rodríguez de Rivera, Miriam; Rodríguez de Rivera, Manuel

    2017-11-28

    The accuracy of the direct and local measurements of the heat power dissipated by the surface of the human body, using a calorimetry minisensor, is directly related to the calibration rigor of the sensor and the correct interpretation of the experimental results. For this, it is necessary to know the characteristics of the body's local heat dissipation. When the sensor is placed on the surface of the human body, the body reacts until a steady state is reached. We propose a mathematical model that represents the rate of heat flow at a given location on the surface of a human body by the sum of a series of exponentials: W ( t ) = A ₀ + ∑A i exp( -t / τ i ). In this way, transient and steady states of heat dissipation can be interpreted. This hypothesis has been tested by simulating the operation of the sensor. At the steady state, the power detected in the measurement area (4 cm²) varies depending on the sensor's thermostat temperature, as well as the physical state of the subject. For instance, for a thermostat temperature of 24 °C, this power can vary between 100-250 mW in a healthy adult. In the transient state, two exponentials are sufficient to represent this dissipation, with 3 and 70 s being the mean values of its time constants.

  9. Theoretical Aspects of Differential Scanning Calorimetry as a Tool for the Studies of Equilibrium Thermodynamics in Pharmaceutical Solid Phase Transitions.

    Science.gov (United States)

    Faroongsarng, Damrongsak

    2016-06-01

    Although differential scanning calorimetry (DSC) is a non-equilibrium technique, it has been used to gain energetic information that involves phase equilibria. DSC has been widely used to characterize the equilibrium melting parameters of small organic pharmaceutical compounds. An understanding of how DSC measures an equilibrium event could make for a better interpretation of the results. The aim of this mini-review was to provide a theoretical insight into the DSC measurement to obtain the equilibrium thermodynamics of a phase transition especially the melting process. It was demonstrated that the heat quantity obtained from the DSC thermogram (ΔH) was related to the thermodynamic enthalpy of the phase transition (ΔH (P) ) via: ΔH = ΔH (P) /(1 + K (- 1)) where K was the equilibrium constant. In melting, the solid and liquefied phases presumably coexist resulting in a null Gibbs free energy that produces an infinitely larger K. Thus, ΔH could be interpreted as ΔH (P). Issues of DSC investigations on melting behavior of crystalline solids including polymorphism, degradation impurity due to heating in situ, and eutectic melting were discussed. In addition, DSC has been a tool for determination of the impurity based on an ideal solution of the melt that is one of the official methods used to establish the reference standard.

  10. Progress in the Development of the Lead Tungstate Crystals for EM-Calorimetry in High-Energy Physics

    Science.gov (United States)

    Novotny, R. W.; Brinkmann, K.-T.; Borisevich, A.; Dormenev, V.; Houzvicka, J.; Korjik, M.; Zaunick, H.-G.

    2017-11-01

    Even at present time there is a strong interest and demand for high quality lead tungstate crystals (PbWO4, PWO) for electromagnetic (EM) calorimetry. PWO is implemented into the EM calorimeter of the CMS-ECAL detector at LHC [1] and required for the completion of the PANDA EMC [2] and various ongoing detector projects at Jefferson Lab. The successful mass production of PWO using the Czochralski method was stopped after bankruptcy of the Bogoroditsk Technical Chemical Plant (BTCP) in Russia as major producer so far. The Shanghai Institute of Ceramics, Chinese Academy of Science (China) was considered as an alternative producer using the modified Bridgman method. The company CRYTUR (Turnov, Czech Republic) with good experience in the development and production of different types of inorganic oxide crystals has restarted at the end of 2014 the development of lead tungstate for mass production based on the Czochralski method. An impressive progress was achieved since then. The growing technology was optimized to produce full size samples with the quality meeting the PANDA-EMC specifications for PWO-II. We will present a detailed progress report on the research program in collaboration with groups at Orsay and JLab. The full size crystals will be characterized with respect to optical performance, light yield, kinetics and radiation hardness.

  11. Effect of polyglycerol esters additive on palm oil crystallization using focused beam reflectance measurement and differential scanning calorimetry.

    Science.gov (United States)

    Saw, M H; Hishamuddin, E; Chong, C L; Yeoh, C B; Lim, W H

    2017-01-01

    The effect of 0.1-0.7% (w/w) of polyglycerol esters (PGEmix-8) on palm oil crystallization was studied using focused beam reflectance measurement (FBRM) to analyze the in-line changes of crystal size distribution during the crystallization. FBRM results show that 0.1-0.5% (w/w) of PGEmix-8 did not significantly affect nucleation but slightly retarded crystal growth. The use of 0.7% (w/w) additive showed greater heterogeneous nucleation compared to those with lower dosages of additive. Crystal growth was also greatly reduced when using 0.7% (w/w) dosage. The morphological study indicated that the palm oil crystals were smaller and more even in size than when more additive was added. Isothermal crystallization studies using differential scanning calorimetry (DSC) showed increased inhibitory effects on palm oil crystal growth with increasing concentration of PGEmix-8. These results imply that PGEmix-8 is a nucleation enhancing and crystal growth retarding additive in palm oil crystallization at 0.7% (w/w) dosage. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  12. Mathematical Model for Localised and Surface Heat Flux of the Human Body Obtained from Measurements Performed with a Calorimetry Minisensor

    Science.gov (United States)

    Socorro, Fabiola; Rodríguez de Rivera, Pedro Jesús; Rodríguez de Rivera, Miriam

    2017-01-01

    The accuracy of the direct and local measurements of the heat power dissipated by the surface of the human body, using a calorimetry minisensor, is directly related to the calibration rigor of the sensor and the correct interpretation of the experimental results. For this, it is necessary to know the characteristics of the body’s local heat dissipation. When the sensor is placed on the surface of the human body, the body reacts until a steady state is reached. We propose a mathematical model that represents the rate of heat flow at a given location on the surface of a human body by the sum of a series of exponentials: W(t) = A0 + ∑Aiexp(−t/τi). In this way, transient and steady states of heat dissipation can be interpreted. This hypothesis has been tested by simulating the operation of the sensor. At the steady state, the power detected in the measurement area (4 cm2) varies depending on the sensor’s thermostat temperature, as well as the physical state of the subject. For instance, for a thermostat temperature of 24 °C, this power can vary between 100–250 mW in a healthy adult. In the transient state, two exponentials are sufficient to represent this dissipation, with 3 and 70 s being the mean values of its time constants. PMID:29182567

  13. High-Pressure Raman and Calorimetry Studies of Vanadium(III) Alkyl Hydrides for Kubas-Type Hydrogen Storage.

    Science.gov (United States)

    Morris, Leah; Trudeau, Michel L; Reed, Daniel; Book, David; Antonelli, David M

    2016-03-16

    Reversible hydrogen storage under ambient conditions has been identified as a major bottleneck in enabling a future hydrogen economy. Herein, we report an amorphous vanadium(III) alkyl hydride gel that binds hydrogen through the Kubas interaction. The material possesses a gravimetric adsorption capacity of 5.42 wt % H2 at 120 bar and 298 K reversibly at saturation with no loss of capacity after ten cycles. This corresponds to a volumetric capacity of 75.4 kgH2  m(-3) . Raman experiments at 100 bar confirm that Kubas binding is involved in the adsorption mechanism. The material possesses an enthalpy of H2 adsorption of +0.52 kJ mol(-1) H2 , as measured directly by calorimetry, and this is practical for use in a vehicles without a complex heat management system. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Calorimetric vs. van't Hoff binding enthalpies from isothermal titration calorimetry: Ba2+-crown ether complexation.

    Science.gov (United States)

    Mizoue, Laura S; Tellinghuisen, Joel

    2004-07-01

    The 1:1 complexation reaction between Ba(2+) and 18-crown-6 ether is re-examined using isothermal titration calorimetry (ITC), with the goal of clarifying previously reported discrepancies between reaction enthalpies estimated directly (calorimetric) and indirectly, from the temperature dependence of the reaction equilibrium constant K (van't Hoff). The ITC thermograms are analyzed using three different non-linear fit models based on different assumptions about the data error: constant, proportional to the heat and proportional but correlated. The statistics of the fitting indicate a preference for the proportional error model, in agreement with expectations for the conditions of the experiment, where uncertainties in the delivered titrant volume should dominate. With attention to proper procedures for propagating statistical error in the van't Hoff analysis, the differences between Delta H(cal) and Delta H(vH) are deemed statistically significant. In addition, statistically significant differences are observed for the Delta H(cal) estimates obtained for two different sources of Ba(2+), BaCl(2) and Ba(NO(3))(2). The effects are tentatively attributed to deficiencies in the standard procedure in ITC of subtracting a blank obtained for pure titrant from the thermogram obtained for the sample.

  15. Enthalpy changes during photosynthetic water oxidation tracked by time-resolved calorimetry using a photothermal beam deflection technique.

    Science.gov (United States)

    Krivanek, Roland; Dau, Holger; Haumann, Michael

    2008-03-01

    The energetics of the individual reaction steps in the catalytic cycle of photosynthetic water oxidation at the Mn(4)Ca complex of photosystem II (PSII) are of prime interest. We studied the electron transfer reactions in oxygen-evolving PSII membrane particles from spinach by a photothermal beam deflection technique, allowing for time-resolved calorimetry in the micro- to millisecond domain. For an ideal quantum yield of 100%, the enthalpy change, DeltaH, coupled to the formation of the radical pair Y(Z)(.+)Q(A)(-) (where Y(Z) is Tyr-161 of the D1 subunit of PSII) is estimated as -820 +/- 250 meV. For a lower quantum yield of 70%, the enthalpy change is estimated to be -400 +/- 250 meV. The observed nonthermal signal possibly is due to a contraction of the PSII protein volume (apparent DeltaV of about -13 A(3)). For the first time, the enthalpy change of the O(2)-evolving transition of the S-state cycle was monitored directly. Surprisingly, the reaction is only slightly exergonic. A value of DeltaH(S(3)-->S(0)) of -210 meV is estimated, but also an enthalpy change of zero is within the error range. A prominent nonthermal photothermal beam deflection signal (apparent DeltaV of about +42 A(3)) may reflect O(2) and proton release from the manganese complex, but also reorganization of the protein matrix.

  16. Estimate of the thermal diffusivity of films with a sandwich structure by using pulsed transient analysis and AC calorimetry

    CERN Document Server

    Choi, M H; Park, C H; Kim, S W; Hahn, S H; Seong, D J; Kim, J C

    1999-01-01

    The thermal diffusivity in a direction perpendicular to an epoxy resin film sandwiched between two identical metal layers was measured not only by using a pulsed transient analysis but also by using AC calorimetry. The pulsed transient analysis utilized the surface-temperature decay of the heating pulse from a Q-switched, 2nd harmonic generated Nd:YAG laser. The temperature decay was measured with a HgCdTe infrared detector. After data collection, a nonlinear least-squares regression was performed to estimate the optimal values of several separate thermal parameters by fitting the data to the solutions. Additionally, the thermal diffusivity of the samples was obtained by using the AC calorimetric method which measured the frequency-dependent phase changes of the samples. The thermal diffusivities obtained by the two methods were in the range of 0.07 approx 0.09 x 10 sup - sup 2 cm sup 2 /s, agreed within 8 %, but were lower than the literature values. To improve the results, the contact heat resistance from t...

  17. Rheological Behavior, Granule Size Distribution and Differential Scanning Calorimetry of Cross-Linked Banana (Musa paradisiaca) Starch.

    Science.gov (United States)

    Núñez-Santiago, María C.; Maristany-Cáceres, Amira J.; Suárez, Francisco J. García; Bello-Pérez, Arturo

    2008-07-01

    Rheological behavior at 60 °C, granule size distribution and Differential Scanning Calorimetry (DSC) tests were employed to study the effect of diverse reaction conditions: adipic acid concentration, pH and temperature during cross-linking of banana (Musa paradisiaca) starch. These properties were determined in native banana starch pastes for the purpose of comparison. Rheological behavior from pastes of cross-linked starch at 60 °C did not show hysteresis, probably due the cross-linkage of starch that avoided disruption of granules, elsewhere, native starch showed hysteresis in a thixotropic loop. All pastes exhibited non-Newtonian shear thinning behavior. In all cases, size distribution showed a decrease in the median diameter in cross-linked starches. This condition produces a decrease in swelling capacity of cross-linked starch. The median diameter decreased with an increase of acid adipic concentration; however, an increase of pH and Temperature produced an increase in this variable. Finally, an increase in gelatinization temperature and entalphy (ΔH) were observed as an effect of cross-linkage. An increase in acid adipic concentration produced an increase in Tonset and a decrease in ΔH. pH and temperature. The cross-linked of banana starch produced granules more resistant during the pasting procedure.

  18. Cholesterol affects the interaction between an ionic liquid and phospholipid vesicles. A study by differential scanning calorimetry and nanoplasmonic sensing.

    Science.gov (United States)

    Russo, Giacomo; Witos, Joanna; Rantamäki, Antti H; Wiedmer, Susanne K

    2017-12-01

    The present work aims at studying the interactions between cholesterol-rich phosphatidylcholine-based lipid vesicles and trioctylmethylphosphonium acetate ([P 8881 ][OAc]), a biomass dissolving ionic liquid (IL). The effect of cholesterol was assayed by using differential scanning calorimetry (DSC) and nanoplasmonic sensing (NPS) measurement techniques. Cholesterol-enriched dipalmitoyl-phosphatidylcholine vesicles were exposed to different concentrations of the IL, and the derived membrane perturbation was monitored by DSC. The calorimetric data could suggest that the binding and infiltration of the IL are delayed in the vesicles containing cholesterol. To clarify our findings, NPS was applied to quantitatively follow the resistance of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine incorporating 0, 10, and 50mol% of cholesterol toward the IL exposure over time. The membrane perturbation induced by different concentrations of IL was found to be a concentration dependent process on cholesterol-free lipid vesicles. Moreover, our results showed that lipid depletion in cholesterol-enriched lipid vesicles is inversely proportional to the increasing amount of cholesterol in the vesicles. These findings support that cholesterol-rich lipid bilayers are less susceptible toward membrane disrupting agents as compared to membranes that do not incorporate any sterols. This probably occurs because cholesterol tightens the phospholipid acyl chain packing of the plasma membranes, increasing their resistance and reducing their permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

  19. Mathematical Model for Localised and Surface Heat Flux of the Human Body Obtained from Measurements Performed with a Calorimetry Minisensor

    Directory of Open Access Journals (Sweden)

    Fabiola Socorro

    2017-11-01

    Full Text Available The accuracy of the direct and local measurements of the heat power dissipated by the surface of the human body, using a calorimetry minisensor, is directly related to the calibration rigor of the sensor and the correct interpretation of the experimental results. For this, it is necessary to know the characteristics of the body’s local heat dissipation. When the sensor is placed on the surface of the human body, the body reacts until a steady state is reached. We propose a mathematical model that represents the rate of heat flow at a given location on the surface of a human body by the sum of a series of exponentials: W(t = A0 + ∑Aiexp(−t/τi. In this way, transient and steady states of heat dissipation can be interpreted. This hypothesis has been tested by simulating the operation of the sensor. At the steady state, the power detected in the measurement area (4 cm2 varies depending on the sensor’s thermostat temperature, as well as the physical state of the subject. For instance, for a thermostat temperature of 24 °C, this power can vary between 100–250 mW in a healthy adult. In the transient state, two exponentials are sufficient to represent this dissipation, with 3 and 70 s being the mean values of its time constants.

  20. Study of the crystallization kinetics of LAS glass by differential scanning calorimetry, X-ray diffraction, and beam bending viscometry

    Energy Technology Data Exchange (ETDEWEB)

    Ovono Ovono, D.; Berre, S.; Pradeau, P.; Comte, M. [Corning SAS, Corning European Technology Center, 7 bis, avenue de Valvins, 77210 Avon (France); Bruno, G., E-mail: brunog@corning.com [Corning SAS, Corning European Technology Center, 7 bis, avenue de Valvins, 77210 Avon (France)

    2012-01-10

    Highlights: Black-Right-Pointing-Pointer The crystallization of LAS glass was investigated using XRD, DSC and beam bending viscometry. Black-Right-Pointing-Pointer Different models were used to determine the kinetic parameters for crystallization. Black-Right-Pointing-Pointer The activation energy and Avrami parameters obtained are consistent with reported values. Black-Right-Pointing-Pointer The crystallization of LAS glass occurs with three-dimensional crystals growth. - Abstract: The crystallization kinetics of a commercial lithium-aluminum silicate (LAS) glass were characterized by differential scanning calorimetry (DSC) under non-isothermal conditions, by in-situ X-ray diffraction, and by three point beam bending viscosimeter (BBV). Non-isothermal DSC experiments were conducted at different heating rates. Results show that the crystal growth is controlled by a thermally activated process of the Arrhenius type. The activation energies obtained from isoconversional analysis are close to that extracted using the Johnson-Mehl-Avrami equation. While X-ray diffraction volume fraction data confirm the DSC analysis, it also shows that the crystallite size changes only at the end of the heat treatment protocol, during a hold at temperatures as high as 1000 Degree-Sign C. In this latter case, the crystal growth follows the Ostwald ripening mechanism. Finally, the viscosity measured in the crystallization region by BBV provides the activation energy for viscous flow, and it is slightly higher than the values obtained by DSC.

  1. Review of Scalar Meson Production at $\\sqrt{s}$ = 7 TeV in CMS, U(1)$'$ Gauge Extensions of the MSSM and Calorimetry for Future Colliders

    CERN Document Server

    AUTHOR|(CDS)2075377; Onel, Yasar

    2011-01-01

    The three main parts of this thesis demonstrate our current understanding of certain physics but mostly go beyond our understanding and present novel approaches, both technically and physically. The first part concentrates on the scalar mesons and presents search methodology to enable a better understanding of their existence and structures. The second part discusses one step further on beyond the standard model physics searches. Emphasis is given to discriminating factors between the MSSM and the U(1)0 gauge extended models. The last part discusses a specific readout problem in calorimetry together with its solution and presents the digital hadron calorimetry, which will be an essential part of calorimeter systems of future colliders.

  2. State of the water in crosslinked sulfonated poly(ether ether ketone). Two-dimensional differential scanning calorimetry correlation mapping

    Energy Technology Data Exchange (ETDEWEB)

    Al Lafi, Abdul G. [Department of Chemistry, Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic); Hay, James N., E-mail: cscientific9@aec.org.sy [The School of Metallurgy and Materials, College of Physical Sciences and Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)

    2015-07-20

    Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination.

  3. Thermal evolution of the Ni{sub 3}Fe compound obtained by mechanical alloying as probed by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Popa, F. [Department of Materials Science and Engineering, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Isnard, O. [Institut Néel, CNRS, associé à l’Université de Grenoble J. Fourier, 25 rue des Martyrs, BP 166, 38042 Grenoble (France); Chicinaş, I., E-mail: Ionel.Chicinas@stm.utcluj.ro [Department of Materials Science and Engineering, Technical University of Cluj-Napoca, 103-105 Muncii Avenue, 400641 Cluj-Napoca (Romania); Pop, V. [Faculty of Physics, Babes-Bolyai University, 1 M. Kogălniceanu St., 400084 Cluj-Napoca (Romania)

    2013-03-25

    Highlights: ► Thermal evolution of Ni{sub 3}Fe compound obtained by MA was studied by DSC. ► At low milling times both Ni{sub 3}Fe formation and recrystallization occur during heating. ► Ni{sub 3}Fe grains obtained by milling and Ni{sub 3}Fe new germs produced during heating growth. ► Ni{sub 3}Fe compound recrystallization enthalpy increases by increasing milling time. ► The activation energy of the recrystallization process has been calculated. -- Abstract: An investigation of the formation of Ni{sub 3}Fe soft magnetic material by high energy ball milling combining X-ray as well as neutron diffraction and differential scanning calorimetry (DSC) is presented. The Ni{sub 3}Fe powders have been obtained by mechanical alloying of elemental powders in a planetary mill under argon atmosphere for milling times ranging from 2 h to 28 h. Ni{sub 3}Fe intermetallic compound is obtained after 10–12 h of milling, as showed by X-ray and neutron diffraction and magnetic studies. The obtained crystallite has the mean size of 20 ± 2 nm after 28 h of milling. The DSC curves, recorded for different heating speeds, present a broad transformation reaction of the as-milled powders. The onset temperature of the transition is about 500 °C. The transition has been assigned to the re-crystallization of the nanocrystalline samples. The Curie temperature of Ni{sub 3}Fe is also observed in the DSC curves, indicating the compound formation. DSC studies prove that the activation energy and the re-crystallization enthalpy increase with the milling time, as the compound is formed by milling and his grain size decrease.

  4. Detection of cervical cancer biomarker patterns in blood plasma and urine by differential scanning calorimetry and mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Nichola C Garbett

    Full Text Available Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN and extent of spread of invasive carcinomas of the cervix (IC are needed. Differential scanning calorimetry (DSC has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate

  5. Native ESI Mass Spectrometry Can Help to Avoid Wrong Interpretations from Isothermal Titration Calorimetry in Difficult Situations.

    Science.gov (United States)

    Wolff, Philippe; Da Veiga, Cyrielle; Ennifar, Eric; Bec, Guillaume; Guichard, Gilles; Burnouf, Dominique; Dumas, Philippe

    2017-02-01

    We studied by native ESI-MS the binding of various DNA-polymerase-derived peptides onto DNA-polymerase processivity rings from Escherichia coli, Pseudomonas aeruginosa, and Mycobacterium tuberculosis. These homodimeric rings present two equivalent specific binding sites, which leads to successive formation during a titration experiment of singly- and doubly occupied rings. By using the ESI-MS free-ring spectrum as a ruler, we derived by robust linear regression the fractions of the different ring species at each step of a titration experiment. These results led to accurate Kd values (from 0.03 to 0.5 μM) along with the probability of peptide loss due to gas phase dissociation (GPD). We show that this good quality is due to the increased information content of a titration experiment with a homodimer. Isothermal titration calorimetry (ITC) led with the same binding model to Kd(ITC) values systematically higher than their ESI-MS counterparts and, often, to poor fit of the ITC curves. A processing with two competing modes of binding on the same site requiring determination of two (Kd, ΔH) pairs greatly improved the fits and yielded a second Kd(ITC) close to Kd(ESI-MS). The striking features are: (1) ITC detected a minor binding mode (~20%) of 'low-affinity' that did not appear with ESI-MS; (2) the simplest processing of ITC data with only one (Kd, ΔH) pair led wrongly to the Kd of the low-affinity binding mode but to the ΔH of the high-affinity binding mode. Analogous misleading results might well exist in published data based on ITC experiments. Graphical Abstract ᅟ.

  6. Native ESI Mass Spectrometry Can Help to Avoid Wrong Interpretations from Isothermal Titration Calorimetry in Difficult Situations

    Science.gov (United States)

    Wolff, Philippe; Da Veiga, Cyrielle; Ennifar, Eric; Bec, Guillaume; Guichard, Gilles; Burnouf, Dominique; Dumas, Philippe

    2017-02-01

    We studied by native ESI-MS the binding of various DNA-polymerase-derived peptides onto DNA-polymerase processivity rings from Escherichia coli, Pseudomonas aeruginosa, and Mycobacterium tuberculosis. These homodimeric rings present two equivalent specific binding sites, which leads to successive formation during a titration experiment of singly- and doubly occupied rings. By using the ESI-MS free-ring spectrum as a ruler, we derived by robust linear regression the fractions of the different ring species at each step of a titration experiment. These results led to accurate Kd values (from 0.03 to 0.5 μM) along with the probability of peptide loss due to gas phase dissociation (GPD). We show that this good quality is due to the increased information content of a titration experiment with a homodimer. Isothermal titration calorimetry (ITC) led with the same binding model to Kd(ITC) values systematically higher than their ESI-MS counterparts and, often, to poor fit of the ITC curves. A processing with two competing modes of binding on the same site requiring determination of two (Kd, ΔH) pairs greatly improved the fits and yielded a second Kd(ITC) close to Kd(ESI-MS). The striking features are: (1) ITC detected a minor binding mode ( 20%) of `low-affinity' that did not appear with ESI-MS; (2) the simplest processing of ITC data with only one (Kd, ΔH) pair led wrongly to the Kd of the low-affinity binding mode but to the ΔH of the high-affinity binding mode. Analogous misleading results might well exist in published data based on ITC experiments.

  7. Electrostatic Interactions in the Binding Pathway of a Transient Protein Complex Studied by NMR and Isothermal Titration Calorimetry*

    Science.gov (United States)

    Meneses, Erick; Mittermaier, Anthony

    2014-01-01

    Much of our knowledge of protein binding pathways is derived from extremely stable complexes that interact very tightly, with lifetimes of hours to days. Much less is known about weaker interactions and transient complexes because these are challenging to characterize experimentally. Nevertheless, these types of interactions are ubiquitous in living systems. The combination of NMR relaxation dispersion Carr–Purcell–Meiboom–Gill (CPMG) experiments and isothermal titration calorimetry allows the quantification of rapid binding kinetics for complexes with submillisecond lifetimes that are difficult to study using conventional techniques. We have used this approach to investigate the binding pathway of the Src homology 3 (SH3) domain from the Fyn tyrosine kinase, which forms complexes with peptide targets whose lifetimes are on the order of about a millisecond. Long range electrostatic interactions have been shown to play a critical role in the binding pathways of tightly binding complexes. The role of electrostatics in the binding pathways of transient complexes is less well understood. Similarly to previously studied tight complexes, we find that SH3 domain association rates are enhanced by long range electrostatics, whereas short range interactions are formed late in the docking process. However, the extent of electrostatic association rate enhancement is several orders of magnitudes less, whereas the electrostatic-free basal association rate is significantly greater. Thus, the SH3 domain is far less reliant on electrostatic enhancement to achieve rapid association kinetics than are previously studied systems. This suggests that there may be overall differences in the role played by electrostatics in the binding pathways of extremely stable versus transient complexes. PMID:25122758

  8. Characterization of the kinetic and thermodynamic landscape of RNA folding using a novel application of isothermal titration calorimetry

    Science.gov (United States)

    Vander Meulen, Kirk A.; Butcher, Samuel E.

    2012-01-01

    A novel isothermal titration calorimetry (ITC) method was applied to investigate RNA helical packing driven by the GAAA tetraloop–receptor interaction in magnesium and potassium solutions. Both the kinetics and thermodynamics were obtained in individual ITC experiments, and analysis of the kinetic data over a range of temperatures provided Arrhenius activation energies (ΔH‡) and Eyring transition state entropies (ΔS‡). The resulting rich dataset reveals strongly contrasting kinetic and thermodynamic profiles for this RNA folding system when stabilized by potassium versus magnesium. In potassium, association is highly exothermic (ΔH25°C = −41.6 ± 1.2 kcal/mol in 150 mM KCl) and the transition state is enthalpically barrierless (ΔH‡ = −0.6 ± 0.5). These parameters are sigificantly positively shifted in magnesium (ΔH25°C = −20.5 ± 2.1 kcal/mol, ΔH‡ = 7.3 ± 2.2 kcal/mol in 0.5 mM MgCl2). Mixed salt solutions approximating physiological conditions exhibit an intermediate thermodynamic character. The cation-dependent thermodynamic landscape may reflect either a salt-dependent unbound receptor conformation, or alternatively and more generally, it may reflect a small per-cation enthalpic penalty associated with folding-coupled magnesium uptake. PMID:22058128

  9. Thermal stability and molecular microstructure of heat-induced cereal grains, revealed with Raman molecular microspectroscopy and differential scanning calorimetry.

    Science.gov (United States)

    Khan, Md Majibur Rahman; Yu, Peiqiang

    2013-07-03

    The objectives of the present study were to use Raman molecular microspectroscopy and differential scanning calorimetry (DSC) to reveal molecular thermal stability and thermal degradation behavior of heat-induced cereal grains and reveal the molecular chemistry of the protein structures of cereal grain tissues affected by heat processing and to quantify the protein secondary structures using multicomponent peak modeling Gaussian and Lorentzian methods. Hierarchical cluster analysis (CLA) and principal components analysis (PCA) were also conducted to identify molecular differences in the Raman spectra. Three cereal grain seeds, wheat, triticale, and corn, were used as the model for feed protein in the experiment. The specimens were autoclaved (moist heating) and dry-heated (roasted) at 121 °C for 80 min, respectively. Raman spectroscopy results revealed that there are marked differences in the secondary structures of the proteins subjected to various heating treatments of different cereals. The sensitivity of cereals to moist heating was much higher than the sensitivity to dry heating. The multivariate analyses (CLA and PCA) showed that heat treatment was significantly isolated between the different Raman raw spectra. The DSC study revealed that the thermal degradation behavior of cereals was significantly changed after moist- and dry-heat treatments. The position of the major endothermic peak of dry-heated cereals shifted toward a higher temperature, from 131.7 to 134.0 °C, suggesting the high thermal stability of dry-heated cereals. In contrast, the endothermic peak position was slightly decreased to 132.1 °C in the case of moist autoclaved heating. The digestive behavior and nutritive value of rumen-undegradable protein in animals may be related to the changes of the protein secondary molecular structure and thermal stability of the cereal grain materials, which is attributed by Raman microspectroscopy and DSC endotherm profiles.

  10. Photoacoustic calorimetry studies of CO photo-dissociation from chloramine-T modified horse heart cytochrome-c.

    Science.gov (United States)

    Word, Tarah A; Larsen, Randy W

    2016-12-15

    Treatment of horse heart Cytochrome-c (Cc) with N-chloro-4-toluosulfonamide (Chloramine-t, CT) results in the oxidation of methionine (Met) residues to the corresponding sulfoxide including the distal heme ligand, Met80. The resulting Fe-sulfoxide coordination is sufficiently labile in the ferrous form to be displaced by gaseous ligands, including CO. Photolysis of the CO-CT-Cc complex provides an opportunity to examine ligand binding dynamics that are associated with a relatively rigid distal heme pocket. In this work, photoacoustic calorimetry (PAC) was utilized to obtain the kinetics as well as enthalpy and molar volume changes subsequent to CO photo-dissociation from CO-CT-Cc. Previous photolysis studies of CO-CT-Cc have led to a proposed model for ligand recombination in which the Met80-sulfoxide and CO recombine with the heme on relatively slow timescales (50 μs and ∼500 μs, respectively). The PAC data presented here reveals two additional kinetic phases with lifetimes of <20 ns and 534 ± 75 ns. The fast phase (<20 ns) is associated with an ΔH of 44 ± 5 kcal mol-1 and ΔV of -0.5 ± 0.5 mL mol-1, whereas the slower phase (534 ns) is associated with a small ΔH of 2 ± 3 kcal mol-1 and ΔV of 1 ± 0.5 mL mol-1. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. Hadronic Imaging Calorimetry

    CERN Document Server

    Kaplan, Alexander; Schultz-Coulon, Hans-Christian; Dubbers, Dirk

    This thesis focuses on a prototype of a highly granular hadronic calorimeter at the planned International Linear Collider optimized for the Particle Flow Approach. The 5.3 nuclear interaction lengths deep sandwich calorimeter was built by the CALICE collaboration and consists of 38 active plastic scintillator layers. Steel is used as absorber material and the active layers are subdivided into small tiles. In total 7608 tiles are read out individually via embedded Silicon Photomultipliers (SiPM). The prototype is one of the first large scale applications of these novel and very promising miniature photodetectors. The work described in this thesis comprises the commissioning of the detector and the data acquisition with test beam particles over several months at CERN and Fermilab. The calibration of the calorimeter and the analysis of the recorded data is presented. A method to correct for the temperature dependent response of the SiPM has been developed and implemented. Its successful application shows that it...

  12. Calorimetry in a Nutshell.

    Science.gov (United States)

    Markow, Peter

    1992-01-01

    Provides information on nutritional caloric value determination. Describes the chemical components of peanuts. Explains how to construct a soda can calorimeter for determining the heat released by a burning nut. Describes how to determine calories and kilocalories. Author asserts the activity can be adopted for children of any age. (eight…

  13. Correlation between Temperature-dependent Fatigue Resistance and Differential Scanning Calorimetry Analysis for 2 Contemporary Rotary Instruments.

    Science.gov (United States)

    Arias, Ana; Macorra, José C; Govindjee, Sanjay; Peters, Ove A

    2018-02-02

    The aim of this study was to assess differences in cyclic fatigue (CF) life of contemporary heat-treated nickel-titanium rotary instruments at room and body temperatures and to document corresponding phase transformations. Forty Hyflex EDM (H-EDM) files (Coltene, Cuyahoga Falls, OH [#25/.08, manufactured by electrical discharge machining]) and 40 TRUShape (TS) files (Dentsply Tulsa Dental Specialties, Tulsa, OK [#25/.06v, manufactured by grinding and shape setting]) were divided into 2 groups (n = 20) for CF resistance tests in a water bath either at room (22°C ± 0.5°C) or body temperature (37°C ± 0.5°C). Instruments were rotated in a simulated canal (angle = 60°, radius = 3 mm, and center of the curvature 5 mm from the tip) until fracture occurred. The motor was controlled by an electric circuit that was interrupted after instrument fracture. The mean half-life and beta and eta Weibull parameters were determined and compared. Two instruments of each brand were subjected to differential scanning calorimetry (DSC). While TS instruments lasted significantly longer at room temperature (mean life = 234.7 seconds; 95% confidence interval [CI], 209-263.6) than at body temperature (mean life = 83.2 seconds; 95% CI, 76-91.1), temperature did not affect H-EDM behavior (room temperature mean life = 725.4 seconds; 95% CI, 658.8-798.8 and body temperature mean life = 717.9 seconds; 95% CI, 636.8-809.3). H-EDM instruments significantly outlasted TS instruments at both temperatures. At body temperature, TS was predominantly austenitic, whereas H-EDM was martensitic or in R-phase. TS was in a mixed austenitic/martensitic phase at 22°C, whereas H-EDM was in the same state as at 37°C. H-EDM had a longer fatigue life than TS, which showed a marked decrease in fatigue life at body temperature; neither the life span nor the state of the microstructure in the DSC differed for H-EDM between room or body temperature. Copyright © 2017 American Association of

  14. Fluence correction factors for graphite calorimetry in a low-energy clinical proton beam: I. Analytical and Monte Carlo simulations.

    Science.gov (United States)

    Palmans, H; Al-Sulaiti, L; Andreo, P; Shipley, D; Lühr, A; Bassler, N; Martinkovič, J; Dobrovodský, J; Rossomme, S; Thomas, R A S; Kacperek, A

    2013-05-21

    The conversion of absorbed dose-to-graphite in a graphite phantom to absorbed dose-to-water in a water phantom is performed by water to graphite stopping power ratios. If, however, the charged particle fluence is not equal at equivalent depths in graphite and water, a fluence correction factor, kfl, is required as well. This is particularly relevant to the derivation of absorbed dose-to-water, the quantity of interest in radiotherapy, from a measurement of absorbed dose-to-graphite obtained with a graphite calorimeter. In this work, fluence correction factors for the conversion from dose-to-graphite in a graphite phantom to dose-to-water in a water phantom for 60 MeV mono-energetic protons were calculated using an analytical model and five different Monte Carlo codes (Geant4, FLUKA, MCNPX, SHIELD-HIT and McPTRAN.MEDIA). In general the fluence correction factors are found to be close to unity and the analytical and Monte Carlo codes give consistent values when considering the differences in secondary particle transport. When considering only protons the fluence correction factors are unity at the surface and increase with depth by 0.5% to 1.5% depending on the code. When the fluence of all charged particles is considered, the fluence correction factor is about 0.5% lower than unity at shallow depths predominantly due to the contributions from alpha particles and increases to values above unity near the Bragg peak. Fluence correction factors directly derived from the fluence distributions differential in energy at equivalent depths in water and graphite can be described by kfl = 0.9964 + 0.0024·zw-eq with a relative standard uncertainty of 0.2%. Fluence correction factors derived from a ratio of calculated doses at equivalent depths in water and graphite can be described by kfl = 0.9947 + 0.0024·zw-eq with a relative standard uncertainty of 0.3%. These results are of direct relevance to graphite calorimetry in low-energy protons but given that the fluence

  15. An absorbed dose to water standard for HDR 192Ir brachytherapy sources based on water calorimetry: numerical and experimental proof-of-principle.

    Science.gov (United States)

    Sarfehnia, Arman; Stewart, Kristin; Seuntjens, Jan

    2007-12-01

    Water calorimetry is an established technique for absorbed dose to water measurements in external beams. In this paper, the feasibility of direct absorbed dose measurements for high dose rate (HDR) iridium-192 (192Ir) sources using water calorimetry is established. Feasibility is determined primarily by a balance between the need to obtain sufficient signal to perform a reproducible measurement, the effect of heat loss on the measured signal, and the positioning uncertainty affecting the source-detector distance. The heat conduction pattern generated in water by the Nucletron microSelectron-HDR 192Ir brachytherapy source was simulated using COMSOL MULTIPHYSICS software. Source heating due to radiation self-absorption was calculated using EGSnrcMP. A heat-loss correction k(c) was calculated as the ratio of the temperature rise under ideal conditions to temperature rise under realistic conditions. The calorimeter setup used a parallel-plate calorimeter vessel of 79 mm diameter and 1.12 mm thick front and rear glass windows located 24 mm apart. Absorbed dose was measured with two sources with nominal air kerma strengths of 38 000 and 21 000 U, at source-detector separations ranging from 24.7 to 27.6 mm and irradiation times of 36.0 to 80.0 s. The preliminary measured dose rate per unit air kerma strength of (0.502 +/- 0.007) microGy/(s U) compares well with the TG-43 derived 0.505 microGy/(s U). This work shows that combined dose uncertainties of significantly less than 5% can be achieved with only modest modifications of current water calorimetry techniques and instruments. This work forms the basis of a potential future absolute dose to water standard for HDR 192Ir brachytherapy.

  16. Solid state and sub-cooled liquid vapour pressures of substituted dicarboxylic acids using Knudsen Effusion Mass Spectrometry (KEMS and Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    A. M. Booth

    2010-05-01

    Full Text Available Solid state vapour pressures of a selection of atmospherically important substituted dicarboxylic acids have been measured using Knudsen Effusion Mass Spectrometry (KEMS over a range of 20 K (298–318 K. Enthalpies of fusion and melting points obtained using Differential Scanning Calorimetry (DSC were used to obtain sub-cooled liquid vapour pressures. They have been compared to estimation methods used on the E-AIM website. These methods are shown to poorly represent – OH groups in combination with COOH groups. Partitioning calculations have been performed to illustrate the impact of the different estimation methods on organic aerosol mass compared to the use of experimental data.

  17. Ion-molecular interactions in solutions of potassium and cadmium thiocyanates in N-methylpyrrolidone at 298.15 k, according to calorimetry and densitometry data

    Science.gov (United States)

    Rassokhina, L. Yu.; Novikov, A. N.

    2013-11-01

    The heat capacity and density of KNCS-N-methylpyrrolidone (MP), Cd(NCS)2-MP, and KNCS-Cd(NCS)2-MP solutions at 298.15 K are studied by means of calorimetry and densitometry. Standard partial molar heat capacities and volumes ( and ) of the studied electrolytes in MP are calculated. Standard values of heat capacity and volume of NCS- ions in MP at 298.15 K are determined. Values of the heat capacity and volume changes upon the formation of the three-component system KNCS-Cd(NCS)2-MP from binary solutions are obtained and discussed.

  18. Ionic molecular interactions in solutions of alkali metal iodides in N-methylpyrrolidone at 298.15 K according to calorimetry and densimetry data

    Science.gov (United States)

    Novikov, A. N.; Rassokhina, L. Yu.

    2015-12-01

    The heat capacity and density of the ternary solutions of NaI-KI- N-methylpyrrolidone (MP), NaI-RbI-MP, KI-RbI-MP, and KI-BaI2-MP at 298.15 K were studied by calorimetry and densimetry. The changes in the heat capacity and volume during the formation of the ternary systems from binary solutions were calculated and discussed. Ion association was found to dominate during the mixing of electrolyte solutions of this type in MP, with ion resolvation occasionally producing a significant effect on ion association.

  19. A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry

    DEFF Research Database (Denmark)

    Wu, Min; Johannesson, Björn; Geiker, Mette

    2014-01-01

    by the ions presented in the pore solution were determined. The influence of the freezing/melting point depression caused by the ions on the determined pore size distribution by LTC was demonstrated. Thermodynamic modeling using the program PHREEQC was performed on the cylinder and powder samples of cement......Thermodynamic modeling was used to predict the ionic concentrations in the pore solution of cement pastes at different temperatures during a freezing and melting measurement in low temperature calorimetry (LTC) studies. By using the predicted ionic concentrations, the temperature depressions caused...

  20. Evaluation of thermal stability of paraffin wax by differential scanning calorimetry; Avaliacao da estabilidade termica de parafina por calorimetria diferencial de varredura

    Energy Technology Data Exchange (ETDEWEB)

    Godinho, K.O.; Silva, A.G.P.; Holanda, J.N.F. [Universidade Estadual do Norte Fluminense (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Grupo de Materiais Ceramicos], Email: holanda@uenf.br

    2010-07-01

    Phase change materials for heat storage are used as passive solar energy storage materials, which can be impregnated into construction materials. In this work the thermal stability (heating/cooling cycle) of the paraffin wax was investigated using differential scanning calorimetry. The latent heat and fusion temperature were determined for the following thermal cycles: 0, 30, 180 and 360. The thermal stability for paraffin wax infiltrated in support of gypsum was also determined. The experimental results showed that the paraffin wax showed good thermal stability in the states pure and infiltrated for up to 360 thermal cycles. (author)

  1. Effects of energy supplementation on energy losses and nitrogen balance of steers fed green-chopped wheat pasture I: Calorimetry.

    Science.gov (United States)

    Shreck, A L; Ebert, P J; Bailey, E A; Jennings, J S; Casey, K D; Meyer, B E; Cole, N A

    2017-05-01

    Cattle grazing wheat pasture in the southern Great Plains are sometimes fed an energy supplement; however, the benefits of supplementation on nutrient balance, energy metabolism, and greenhouse gas emissions have not been elucidated. Therefore, we used 10 British crossbred steers (206 ± 10.7 kg initial BW) in a respiration calorimetry study to evaluate the effects of energy supplementation on energy losses, N balance, and nutrient digestibility of steers fed green-chopped wheat forage. The study design was an incomplete replicated 4 × 4 Latin square with treatments in a 2 × 2 factorial arrangement. Steers ( = 8) were assigned to 1 of 2 BW blocks (4 steers per block) with dietary factors consisting of 1) no supplementation (CON) or supplemented with a steam-flaked corn-based energy supplement (that also contained monensin sodium) at 0.5% of BW daily (SUP) and 2) NEm intakes of 1 times (1x) or 1.5 times (1.5x) maintenance. Wheat forage was harvested daily and continuously fed as green-chop to steers during the 56-d study. There were no differences ( ≥ 0.32) between CON and SUP for OM (78.3 vs. 80.7%, respectively) or NDF (68.3 vs. 64.8%, respectively) digestibility. At the 1.5x level of intake, there was no difference ( ≥ 0.16) in energy lost in feces (4.27 vs. 3.92 Mcal/d) or urine (0.58 vs. 0.55 Mcal/d), heat production (8.69 vs. 8.44 Mcal/d), or retained energy (3.10 vs. 3.46 Mcal/d) between supplementation treatments. Oxygen consumption (1,777 vs. 1,731 L/d; = 0.67) and CO production (1,704 vs. 1,627 L/d; = 0.56) of CON and SUP steers, respectively, were not different; however, SUP steers tended to have ( = 0.06) lower CH production (115 vs 130 L/d) than CON steers. Methane, as a proportion of GE intake, was similar for CON (6.87%) and SUP (6.07%; = 0.18), as was the ME:DE ratio ( = 0.24; 86.3% for CON and 87.9% for SUP). Fractional N excretion in urine and feces, as a proportion of total N excreted ( ≥ 0.84) or N intake ( ≥ 0.63), was not different

  2. Two-Phase Calorimetry. II. Studies on the Thermodynamics of Cesium and Strontium Extraction by Mixtures of H+CCD- and PEG-400 in FS-13

    Energy Technology Data Exchange (ETDEWEB)

    Zalupski, Peter R. [Idaho National Laboratory (INL); Herbst, R. S. [Idaho National Laboratory (INL); Delmau, Laetitia Helene [ORNL; Martin, L. R. [Idaho National Laboratory (INL); Peterman, D. R. [Idaho National Laboratory (INL); Nash, Ken L [Washington State University

    2010-01-01

    Thermochemical characterization of the partitioning of cesium and strontium from nitric acid solutions into mixtures of the acid form of chlorinated cobalt dicarbollide (H+CCD-) and polyethylene glycol (PEG-400) in FS-13 diluent has been completed using isothermal titration microcalorimetry and radiotracer distribution methods. The phase transfer reaction for Cs+ is a straightforward (H+ for Cs+) cation exchange reaction. In contrast, the extraction of Sr2+ does not proceed in the absence of the co-solvent molecule PEG-400. This molecule is believed to facilitate the dehydration of the Sr2+ aquo cation to overcome its resistance to partitioning. The phase transfer reactions for both Cs+ and Sr2+ are enthalpy driven (exothermic), but partially compensated by an unfavorable entropy. The results of the calorimetry studies suggest that the PEG-400 functions as a stoichiometric phase transfer reagent rather than acting simply as a phase transfer catalyst or phase modifier. The calorimetry results also demonstrate that the extraction of Sr2+ is complex, including evidence for both the partitioning of Sr(NO3)+ and endothermic ion pairing interactions in the organic phase that contribute to the net enthalpic effect. The thermodynamics of the liquid-liquid distribution equilibria are discussed mainly considering the basic features of the ion solvation thermochemistry.

  3. A preliminary study of the influence of ions in the pore solution of hardened cement pastes on the porosity determination by low temperature calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Min, E-mail: miwu@byg.dtu.dk [Department of Civil Engineering, Technical University of Denmark, Building 118, 2800 Lyngby (Denmark); Johannesson, Björn [Department of Civil Engineering, Technical University of Denmark, Building 118, 2800 Lyngby (Denmark); Geiker, Mette [Department of Structural Engineering, Norwegian University of Science and Technology, Trondheim (Norway)

    2014-08-10

    Highlights: • Ionic concentrations in cement pore solution at freezing temperatures were simulated. • Effects of ions in determining pore sizes by low temperature calorimetry were studied. • Ions in cement pore solution affect the pore size determination to a limited extent. - Abstract: Thermodynamic modeling was used to predict the ionic concentrations in the pore solution of cement pastes at different temperatures during a freezing and melting measurement in low temperature calorimetry (LTC) studies. By using the predicted ionic concentrations, the temperature depressions caused by the ions presented in the pore solution were determined. The influence of the freezing/melting point depression caused by the ions on the determined pore size distribution by LTC was demonstrated. Thermodynamic modeling using the program PHREEQC was performed on the cylinder and powder samples of cement pastes prepared by two types of cements, i.e., CEM I 32.5 R and CEM III/B 42.5 N. Using the modeled ionic concentrations, the calculated differential pore size distributions for the studied samples with and without considering the temperature depression caused by the ions in the pore solution were compared. The results indicate that for the studied cement paste samples, the influence of the temperature depression caused by the presence of the ions in the pore solution on the determination of the pore size distribution by LTC is limited.

  4. Ligand binding to one-dimensional lattice-like macromolecules: analysis of the McGhee-von Hippel theory implemented in isothermal titration calorimetry.

    Science.gov (United States)

    Velázquez-Campoy, Adrián

    2006-01-01

    The theory developed by McGhee and von Hippel for ligand binding to a one-dimensional lattice-like macromolecule provides a closed analytical form in the Scatchard representation. The application of such theory has been complicated by two facts: (1) it has been practically reduced to binding techniques, such as equilibrium dialysis, in which the partition between bound and free concentrations of all reactant species are directly accessible and experimentally determined, but infrequently applied to other binding techniques, such as calorimetry or spectroscopy, in which the direct observable is a magnitude proportional to the advance of the binding reaction monitored along the titration experiment, and (2) Scatchard analysis, developed as a quantitative graphical method, is currently outdated and used only qualitatively because of its weaknesses, limitations, and deficiencies. However, a general exact method for applying such theory to titration techniques in a correct and precise manner, without any limitation, can be delineated. In this article, the theory of cooperative ligand binding to linear lattice-like macromolecules has been implemented in isothermal titration calorimetry for the first time. This technique provides a complete thermodynamic characterization of ligand binding, but it has been barely used properly for this type of system. The description, the analysis of the formalism, and practical guidelines are presented, with considerations for experimental design and data analysis.

  5. Determination of the net energy content of canola meal from Brassica napus yellow and Brassica juncea yellow fed to growing pigs using indirect calorimetry.

    Science.gov (United States)

    Heo, Jung Min; Adewole, Deborah; Nyachoti, Martin

    2014-07-01

    The net energy (NE) content of canola meals (CM; i.e. Brassica napus yellow and Brassica juncea yellow) in growing pigs was determined using an indirect calorimetry chamber or published prediction equations. The study was conducted as a completely randomized design (n=6), with (i) a basal diet and (ii) 2 diets containing 700 g/kg of the basal diet and 300 g/kg of either of the two varieties of CM. A total of 18 growing barrows were housed in metabolism crates for the determination of digestible (DE) and metabolizable (ME) energy. Thereafter, pigs were transferred to the indirect calorimetry chamber to determine heat production (HP). The NE contents of diets containing Brassica napus yellow and Brassica juncea yellow determined with the direct determination technique and prediction equations were 9.8 versus 10.3 MJ/kg dry matter (DM) and 10.2 versus 10.4 MJ/kg DM, respectively. Retained energy (RE) and fasting heat production (FHP) of diets containing Brassica napus yellow and Brassica juncea yellow were 5.5 versus 5.7 MJ/kg and 4.3 versus 4.5 MJ/kg, respectively, when measured with the direct determination technique and prediction equations. The NE contents of Brassica napus yellow and Brassica juncea yellow were determined to be 8.8 and 9.8 MJ/kg DM, respectively, using the direct determination technique. © 2014 Japanese Society of Animal Science.

  6. Low-temperature phase transition in glycine-glutaric acid co-crystals studied by single-crystal X-ray diffraction, Raman spectroscopy and differential scanning calorimetry.

    Science.gov (United States)

    Zakharov, Boris A; Losev, Evgeniy A; Kolesov, Boris A; Drebushchak, Valeri A; Boldyreva, Elena V

    2012-06-01

    The occurrence of a first-order reversible phase transition in glycine-glutaric acid co-crystals at 220-230 K has been confirmed by three different techniques - single-crystal X-ray diffraction, polarized Raman spectroscopy and differential scanning calorimetry. The most interesting feature of this phase transition is that every second glutaric acid molecule changes its conformation, and this fact results in the space-group symmetry change from P2(1)/c to P1. The topology of the hydrogen-bonded motifs remains almost the same and hydrogen bonds do not switch to other atoms, although the hydrogen bond lengths do change and some of the bonds become inequivalent.

  7. Evaluation of shrinkage temperature of bovine pericardium tissue for bioprosthetic heart valve application by differential scanning calorimetry and freeze-drying microscopy

    Directory of Open Access Journals (Sweden)

    Virgilio Tattini Jr

    2007-03-01

    Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.

  8. Dimyristoylphosphatidylcholine/C16 : 0-ceramide binary liposomes studied by differential scanning calorimetry and wide- and small-angle X-ray scattering

    DEFF Research Database (Denmark)

    Holopainen, J. M.; Lemmich, Jesper; Richter, F.

    2000-01-01

    hysteresis in the thermal phase behavior of ceramide-containing membranes. A partial phase diagram was constructed based on results from a combination of these two methods. DSC heating scans show that with increased X-cer the pretransition temperature T-P first increases, whereafter at X-cer > 0.06 it can......Ceramide has recently been established as a central messenger in the signaling cascades controlling cell behavior. Physicochemical studies have revealed a strong tendency of this lipid toward phase separation in mixtures with phosphatidylcholines. The thermal phase behavior and structure of fully...... hydrated binary membranes composed of dimyristoylphosphatidylcholine (DMPC) and N-palmitoyl-ceramide (C16:0-ceramide, up to a mole fraction X-cer = 0.35) were resolved in further detail by high-sensitivity differential scanning calorimetry (DSC) and x-ray diffraction. Both methods reveal very strong...

  9. HypCal, a general-purpose computer program for the determination of standard reaction enthalpy and binding constant values by means of calorimetry.

    Science.gov (United States)

    Arena, Giuseppe; Gans, Peter; Sgarlata, Carmelo

    2016-09-01

    The program HypCal has been developed to provide a means for the simultaneous determination, from data obtained by isothermal titration calorimetry, of both standard enthalpy of reaction and binding constant values. The chemical system is defined in terms of species of given stoichiometry rather than in terms of binding models (e.g., independent or cooperative). The program does not impose any limits on the complexity of the chemical systems that can be treated, including competing ligand systems. Many titration curves may be treated simultaneously. HypCal can also be used as a simulation program when designing experiments. The use of the program is illustrated with data obtained with nicotinic acid (niacin, pyridine-3 carboxylic acid). Preliminary experiments were used to establish the rather different titration conditions for the two sets of titration curves that are needed to determine the parameters for protonation of the carboxylate and amine groups.

  10. Shape Memory Alloys for Monitoring Minor Over-Heating/Cooling Based on the Temperature Memory Effect via Differential Scanning Calorimetry: A Review of Recent Progress

    Science.gov (United States)

    Wang, T. X.; Huang, W. M.

    2017-12-01

    The recent development in the temperature memory effect (TME) via differential scanning calorimetry in shape memory alloys is briefly discussed. This phenomenon was also called the thermal arrest memory effect in the literature. However, these names do not explicitly reveal the potential application of this phenomenon in temperature monitoring. On the other hand, the standard testing process of the TME has great limitation. Hence, it cannot be directly applied for temperature monitoring in most of the real engineering applications in which temperature fluctuation occurs mostly in a random manner within a certain range. However, as shown here, after proper modification, we are able to monitor the maximum or minimum temperature in either over-heating or over-cooling with reasonable accuracy.

  11. Shape Memory Alloys for Monitoring Minor Over-Heating/Cooling Based on the Temperature Memory Effect via Differential Scanning Calorimetry: A Review of Recent Progress

    Science.gov (United States)

    Wang, T. X.; Huang, W. M.

    2017-10-01

    The recent development in the temperature memory effect (TME) via differential scanning calorimetry in shape memory alloys is briefly discussed. This phenomenon was also called the thermal arrest memory effect in the literature. However, these names do not explicitly reveal the potential application of this phenomenon in temperature monitoring. On the other hand, the standard testing process of the TME has great limitation. Hence, it cannot be directly applied for temperature monitoring in most of the real engineering applications in which temperature fluctuation occurs mostly in a random manner within a certain range. However, as shown here, after proper modification, we are able to monitor the maximum or minimum temperature in either over-heating or over-cooling with reasonable accuracy.

  12. The effect of increasing membrane curvature on the phase transition and mixing behavior of a dimyristoyl-sn-glycero-3-phosphatidylcholine/distearoyl-sn-glycero-3-phosphatidylcholine lipid mixture as studied by Fourier transform infrared spectroscopy and differential scanning calorimetry

    DEFF Research Database (Denmark)

    Brumm, T.; Jørgensen, Kent; Mouritsen, Ole G.

    1996-01-01

    The phase transition behavior of a lipid bilayer of dimyristoyl-sn-glycero-3-phosphalidylcholine/distearoyl-sn- glycero-3-phosphatidylcholine (DMPC-d54/DSPC) (1:1) on a solid support with varying curvatures was investigated with differential scanning calorimetry, infrared spectroscopy, and model...

  13. Structure, activity and thermostability investigations of OXA-163, OXA-181 and OXA-245 using biochemical analysis, crystal structures and differential scanning calorimetry analysis.

    Science.gov (United States)

    Lund, Bjarte Aarmo; Thomassen, Ane Molden; Carlsen, Trine Josefine Olsen; Leiros, Hanna Kirsti S

    2017-10-01

    The first crystal structures of the class D β-lactamases OXA-181 and OXA-245 were determined to 2.05 and 2.20 Å resolution, respectively; in addition, the structure of a new crystal form of OXA-163 was resolved to 2.07 Å resolution. All of these enzymes are OXA-48-like and have been isolated from different clinical Klebsiella pneumoniae strains and also from other human pathogens such as Pseudomonas aeruginosa and Escherichia coli. Here, enzyme kinetics and thermostability studies are presented, and the new crystal structures are used to explain the observed variations. OXA-245 had the highest melting point (T m = 55.8°C), as determined by differential scanning calorimetry, compared with OXA-163 (T m = 49.4°C) and OXA-181 (T m = 52.6°C). The differences could be explained by the loss of two salt bridges in OXA-163, and an overall decrease in the polarity of the surface of OXA-181 compared with OXA-245.

  14. Vibrational spectroscopic characterisation of salmeterol xinafoate polymorphs and a preliminary investigation of their transformation using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Ali, Hassan Refat H. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom); Edwards, Howell G.M. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom)], E-mail: H.G.M.Edwards@bradford.ac.uk; Hargreaves, Michael D.; Munshi, Tasnim; Scowen, Ian J.; Telford, Richard J. [Chemical and Forensic Sciences/University Analytical Centre, School of Life Sciences, University of Bradford, Richmond Road, Bradford BD7 1DP (United Kingdom)

    2008-07-14

    Knowledge and control of the polymorphic phases of chemical compounds are important aspects of drug development in the pharmaceutical industry. Salmeterol xinafoate, a long acting {beta}-adrenergic receptor agonist, exists in two polymorphic Forms, I and II. Raman and near infrared spectra were obtained of these polymorphs at selected wavelengths in the range of 488-1064 nm; significant differences in the Raman and near-infrared spectra were apparent and key spectral marker bands have been identified for the vibrational spectroscopic characterisation of the individual polymorphs which were also characterised with X ray diffractometry. The solid-state transition of salmeterol xinafoate polymorphs was studied using simultaneous in situ portable Raman spectroscopy and differential scanning calorimetry isothermally between transitions. This method assisted in the unambiguous characterisation of the two polymorphic forms by providing a simultaneous probe of both the thermal and vibrational data. The study demonstrates the value of a rapid in situ analysis of a drug polymorph which can be of potential value for at-line in-process control.

  15. Characterization of crystallization kinetics of a Ni- (Cr, Fe, Si, B, C, P) based amorphous brazing alloy by non-isothermal differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Raju, S. [Physical Metallurgy Section, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102 (India)]. E-mail: sraju@igcar.gov.in; Kumar, N.S. Arun [Physical Metallurgy Section, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102 (India); Jeyaganesh, B. [Physical Metallurgy Section, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102 (India); Mohandas, E. [Physical Metallurgy Section, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102 (India); Mudali, U. Kamachi [Corrosion Science and Technology Division, Indira Gandhi Centre for Atomic Research, Kalpakkam, Tamil Nadu 603 102 (India)

    2007-08-16

    The thermal stability and crystallization kinetics of a Ni- (Cr, Si, Fe, B, C, P) based amorphous brazing foil have been investigated by non-isothermal differential scanning calorimetry. The glass transition temperature T {sub g}, is found to be 720 {+-} 2 K. The amorphous alloy showed three distinct, yet considerably overlapping crystallization transformations with peak crystallization temperatures centered around 739, 778 and 853 {+-} 2 K, respectively. The solidus and liquidus temperatures are estimated to be 1250 and 1300 {+-} 2 K, respectively. The apparent activation energies for the three crystallization reactions have been determined using model free isoconversional methods. The typical values for the three crystallization reactions are: 334, 433 and 468 kJ mol{sup -1}, respectively. The X-ray diffraction of the crystallized foil revealed the presence of following compounds Ni{sub 3}B (Ni{sub 4}B{sub 3}), CrB, B{sub 2}Fe{sub 15}Si{sub 3}, CrSi{sub 2}, and Ni{sub 4.5}Si{sub 2}B.

  16. Preformulation Studies of Zidovudine Derivatives: Acid Dissociation Constants, Differential Scanning Calorimetry, Thermogravimetry, X-Ray Powder Diffractometry and Aqueous Stability Studies

    Science.gov (United States)

    Raviolo, Mónica A.; Briñón, Margarita C.

    2011-01-01

    As part as of the preformulation studies of new 5′-OH derivatives of zidovudine, compounds 2–6, their acid dissociation constants, Differential Scanning Calorimetry (DSC) and Thermogravimetry (TG) curves, X-Ray Powder diffractograms and aqueous stability are reported. A sensitive technique such as differential scanning potentiometry was used to determine the pKa constants of the above mentioned compounds. In addition, pKa values were calculated from theoretical methods, and no significant differences with those of experimental ones were observed. X-Ray Powder Diffractometry data demonstrated that compounds 2–4 were crystalline while 5 and 6 were amorphous. DSC analysis indicated that all of them presented an exothermic decomposition peak above 150 °C which is accompanied by a weight loss in the respective TG curves. The stability of these compounds in aqueous medium at different pH values was investigated, using a validated High Performance Liquid Chromatography (HPLC) method, which demonstrated to be rapid, selective, sensitive, accurate and stability-indicating. Good recovery, linearity and precision were also achieved. For all compounds the aqueous hydrolysis followed a pseudo-first-order kinetics, depending on pH and the union existing between AZT and the associate moiety. The hydrolysis was catalyzed by hydroxide ion in the 7.4–13.2 pH range, while all compounds exhibited pH-independent stability from acidic to neutral media (pHs 1.0–7.4). PMID:21886898

  17. The question of high- or low-temperature glass transition in frozen fish. Construction of the supplemented state diagram for tuna muscle by differential scanning calorimetry.

    Science.gov (United States)

    Orlien, Vibeke; Risbo, Jens; Andersen, Mogens L; Skibsted, Leif H

    2003-01-01

    The thermal behavior of fresh tuna muscle, rehydrated freeze-dried tuna muscle, and tuna sarcoplasmic protein fraction was studied by three types of differential scanning calorimetry (DSC): conventional DSC, alternating DSC, and sensitive micro-DSC. The relationship between glass transition temperature, T(g), and water content was established. Only a low-temperature glass transition was detected for fresh tuna and freeze-dried tuna rehydrated to high water contents, whereas for sarcoplasmic protein fraction both a low-temperature and an apparent high-temperature glass transition were detected for samples of high water content. Construction of the supplemented state diagrams for whole tuna muscle and for tuna sarcoplasmic protein fraction confirmed the low-temperature transition to be glass transition of the maximally freeze-dehydrated phase. The apparent upper transition of sarcoplasmic protein fraction was shown not to be a glass transition but rather to originate from the onset of melting of ice, and the temperature of this event should be denoted T(m)'. The glass transition temperature and the concentration of the maximally freeze dehydrated tuna muscle are -74 degrees C and 79% (w/w), respectively.

  18. Studying multisite binary and ternary protein interactions by global analysis of isothermal titration calorimetry data in SEDPHAT: application to adaptor protein complexes in cell signaling.

    Science.gov (United States)

    Houtman, Jon C D; Brown, Patrick H; Bowden, Brent; Yamaguchi, Hiroshi; Appella, Ettore; Samelson, Lawrence E; Schuck, Peter

    2007-01-01

    Multisite interactions and the formation of ternary or higher-order protein complexes are ubiquitous features of protein interactions. Cooperativity between different ligands is a hallmark for information transfer, and is frequently critical for the biological function. We describe a new computational platform for the global analysis of isothermal titration calorimetry (ITC) data for the study of binary and ternary multisite interactions, implemented as part of the public domain multimethod analysis software SEDPHAT. The global analysis of titrations performed in different orientations was explored, and the potential for unraveling cooperativity parameters in multisite interactions was assessed in theory and experiment. To demonstrate the practical potential and limitations of global analyses of ITC titrations for the study of cooperative multiprotein interactions, we have examined the interactions of three proteins that are critical for signal transduction after T-cell activation, LAT, Grb2, and Sos1. We have shown previously that multivalent interactions between these three molecules promote the assembly of large multiprotein complexes important for T-cell receptor activation. By global analysis of the heats of binding observed in sets of ITC injections in different orientations, which allowed us to follow the formation of binary and ternary complexes, we observed negative and positive cooperativity that may be important to control the pathway of assembly and disassembly of adaptor protein particles.

  19. Establishment of Heat Treatment Process for Modified 440A Martensitic Stainless Steel Using Differential Scanning Calorimetry and Thermo-Calc Calculation

    Directory of Open Access Journals (Sweden)

    Huei-Sen Wang

    2015-12-01

    Full Text Available To provide a suitable microstructure and mechanical properties for modified Grade 440A martensitic stainless steel (MSS, which could facilitate the further cold deformation process (e.g., cold rolling, this work used differential scanning calorimetry (DSC and Thermo-Calc software to determine three soaking temperatures for annealing heat treatment processes (HT1, HT2 and HT3. To verify the feasibility of the proposed annealing heat treatment processes, the as-received samples were initially heated to 1050 °C (similar to the on-line working temperature for 30 min and air quenched to form a martensitic structure. The air-quenched samples were then subjected to three developed annealing heat treatment conditions. The microstructure and mechanical properties of the heat-treated samples were then investigated. Test results showed that considering the effects of the microstructure and the hardness, the HT1, the HT2 or the soaking temperatures between the HT1 and HT2 were the most recommended processes to modified Grade 440A MSS. When using the recommended processes, their carbides were fine and more evenly distributed, and the microhardness was as low as 210 Hv, which can be applied to the actual production process.

  20. Probing the binding mechanisms of α-tocopherol to trypsin and pepsin using isothermal titration calorimetry, spectroscopic, and molecular modeling methods.

    Science.gov (United States)

    Li, Xiangrong; Ni, Tianjun

    2016-06-01

    α-Tocopherol is a required nutrient for a variety of biological functions. In this study, the binding of α-tocopherol to trypsin and pepsin was investigated using isothermal titration calorimetry (ITC), steady-state and time-resolved fluorescence measurements, circular dichroism (CD) spectroscopy, and molecular modeling methods. Thermodynamic investigations reveal that α-tocopherol binds to trypsin/pepsin is synergistically driven by enthalpy and entropy. The fluorescence experimental results indicate that α-tocopherol can quench the fluorescence of trypsin/pepsin through a static quenching mechanism. The binding ability of α-tocopherol with trypsin/pepsin is in the intermediate range, and one molecule of α-tocopherol combines with one molecule of trypsin/pepsin. As shown by circular dichroism (CD) spectroscopy, α-tocopherol may induce conformational changes of trypsin/pepsin. Molecular modeling displays the specific binding site and gives information about binding forces and α-tocopherol-tryptophan (Trp)/tyrosine (Tyr) distances. In addition, the inhibition rate of α-tocopherol on trypsin and pepsin was studied. The study provides a basic data set for clarifying the binding mechanisms of α-tocopherol with trypsin and pepsin and is helpful for understanding its biological activity in vivo.

  1. Determining the binding site and binding affinity of estradiol to human serum albumin and holo-transferrin: fluorescence spectroscopic, isothermal titration calorimetry and molecular modeling approaches.

    Science.gov (United States)

    Danesh, Nazila; Navaee Sedighi, Zahra; Beigoli, Sima; Sharifi-Rad, Atena; Saberi, Mohammad Reza; Chamani, Jamshidkhan

    2017-06-02

    The interactions between estradiol and two carrier proteins, i.e. human serum albumin (HSA) and holo-transferrin (HTF) in aqueous solution at pH = 7.4 were studied by three-dimensional fluorescence emission spectroscopy, isothermal titration calorimetry (ITC), zeta-potential, resonance light-scattering and molecular modeling. Extensive fluorescence quenching was observed throughout the interaction between the drug and both proteins. Moreover, conformational changes were determined by observing the rearrangement of Trp residues during binding of estradiol with HSA and HTF at different concentrations. ITC experiments revealed that, in the presence of estradiol, both van der Waals forces and hydrogen bonding became predominant. In addition, other binding parameters such as enthalpy and entropy changes were determined by the zeta potential method. Molecular modeling suggested that estradiol was situated within sub-domain IB sited in the hydrophobic cluster in Site I, whereas the drug was located in the N-terminal of HTF where it was hydrogen bonded with Ala 670.

  2. Supramolecular interactions between losartan and hydroxypropyl-β-CD: ESI mass-spectrometry, NMR techniques, phase solubility, isothermal titration calorimetry and anti-hypertensive studies.

    Science.gov (United States)

    de Paula, Washington X; Denadai, Angelo M L; Santoro, Marcelo M; Braga, Aline N G; Santos, Robson A S; Sinisterra, Rubén D

    2011-02-14

    In this work, low soluble supramolecular complex between the losartan potassium (Los) and hydroxypropil-β-cyclodextrin (HPβCD) were characterized throughout phase-solubility, NMR techniques ((1)H and 2D-ROESY) and isothermal titration calorimetry (ITC) in order to attain physical-chemical knowledge of the system. In addition, the hypertensive effect of composition Los/HPβCD was evaluated aiming to obtain a more efficient oral pharmaceutical composition. ESI mass spectrometry and ITC blank experiment demonstrate the presence of Los clusters at 30 mM pure solution. Phase-solubility experiments showed a "Bs" type system, due to the formation of a less soluble complex than pure Los. NMR demonstrated the short distance interactions between the Los and the cyclodextrin, where several possibilities of interactions were observed. ITC data suggest an average 1:1 stoichiometry of Los and the cyclodextrin. The complex demonstrated efficiency in hypertension control, presenting antagonist action on the pressure effect of angiotensin II within 30 h, as compared to Los alone, 6h, indicating that inclusion of Los in HPβCD enhanced the extent and duration of its antagonistic action. In this work, a model of interaction between Los and HPβCD was proposed based on dissociation of self-assembled Los followed by complexation with HPβCD. Copyright © 2010 Elsevier B.V. All rights reserved.

  3. Unraveling the thermodynamics, binding mechanism and conformational changes of HSA with chromolyn sodium: Multispecroscopy, isothermal titration calorimetry and molecular docking studies.

    Science.gov (United States)

    Yasmeen, Shama; Riyazuddeen; Qais, Faizan Abul

    2017-12-01

    Cromolyn sodium is an anti-allergic drug effective for treatment in asthma and allergic rhinitis. In this project, interaction of chromolyn sodium (CS) with human serum albumin (HSA) has been investigated by various techniques such as UV-vis, fluorescence, circular dichorism (CD), fourier transform infrared (FT-IR) spectroscopy, isothermal titration calorimetric (ITC) and molecular docking. The fluorescence quenching results revealed that there was static quenching mechanism in the interactions of CS with HSA. The binding constant (Kb), enthalpy change (ΔH°), entropy change (ΔS°) and Gibbs free energy change (ΔG°) were calculated. The negative values of TΔS° and ΔH° obtained from fluorescence spectroscopy and isothermal titration calorimetry, indicate that hydrogen bonding and van der Waal's forces played major role in the binding process and the reaction is exothermic in nature. The binding constant (Kb) was found to be in the order of 104M-1 which depicts a good binding affinity of CS towards HSA. The conformational changes in the HSA due to interaction of CS were investigated from CD and FT-IR spectroscopy. The binding site of CS in HSA was sub-domain IIA as evident from site probing experiment and molecular docking studies. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Melting, crystallization and storage stability of virgin coconut oil and its blends by differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR).

    Science.gov (United States)

    Srivastava, Yashi; Semwal, Anil Dutt; Sajeevkumar, Vallayil Appukuttan; Sharma, G K

    2017-01-01

    The blends were prepared of virgin coconut oil with refined soyabean oil (VCO-RSOY) and refined safflower oil (VCO-RSAFF). Blending with VCO improved the fatty acid composition which increased the shelf stability of 20:80 VCO-RSOY and VCO-RSAFF up to 12 months in different packaging systems such as low density polyethylene, linear low density polyethylene, metalized polyester pouches, polyethylene teteraphthalate, high density polyethylene (HDPE), Amber HDPE bottle. The specific spectral regions of FTIR proved to be very useful for the determination of adulteration as well as for the study of oxidation process. Band shifts observed at 3008, 1652, 1397, 1097, 912 and 845 cm(-1) have been used to differentiate RSAFF from VCO. VCO spectrums did not have these chemical shifts. Further the spectrum of RSOY showed same band shifts as RSAFF except 1652, 1397, 869.6 and 845 cm(-1). Differential Scanning Calorimetry provided useful information regarding the nature of thermodynamic changes related to physical state of vegetable oil. The physical state changes included melting and crystallization events which require the intake and release of energy.

  5. Thermodynamic study of seven micropollutants adsorption onto an activated carbon cloth: Van't Hoff method, calorimetry, and COSMO-RS simulations.

    Science.gov (United States)

    Masson, Sylvain; Vaulot, Cyril; Reinert, Laurence; Guittonneau, Sylvie; Gadiou, Roger; Duclaux, Laurent

    2017-04-01

    The thermodynamic of the adsorption of seven organic pollutants, namely benzotriazol, bisphenol A, caffeine, carbamazepine, diclofenac, ofloxacin, and pentachlorophenol, was studied on a microporous-activated carbon fabric. The isosteric adsorption quantities (Gibbs energy, enthalpy, and entropy variations) at high coverage ratio (around 1 mmol/g) have been determined from the adsorption isotherms at three temperatures (13, 25, and 40 °C). The adsorption heats at very low coverage (about 10 -5  mmol/g) have been measured by flow micro calorimetry. The experimental adsorption energies were correlated to the adsorbate-adsorbent and the adsorbate-solvent interaction energies calculated by simulations using the COSMO-RS model. The main role of the van der Waals forces in the adsorption of the studied molecules was established. The bulkier the adsorbate is, the lower the adsorption Gibbs energy variation at high coverage deduced from the isotherms. The heterogeneity of the adsorption sites was brought out by calorimetric measurements. At high coverage, a physisorption phenomenon was observed. At very low coverage, high values of the adsorption heats were found (ranging from -58 to -110 kJ/mol), except for pentachlorophenol characterized by an athermal adsorption controlled by Pi-anions interactions.

  6. Simultaneous determination of thermodynamic and kinetic parameters of aminopolycarbonate complexes of cobalt(II) and nickel(II) based on isothermal titration calorimetry data.

    Science.gov (United States)

    Tesmar, Aleksandra; Wyrzykowski, Dariusz; Muñoz, Eva; Pilarski, Bogusław; Pranczk, Joanna; Jacewicz, Dagmara; Chmurzyński, Lech

    2017-04-01

    The influence of the different side chain residues on the thermodynamic and kinetic parameters for complexation reactions of the Co 2 + and Ni 2 + ions has been investigated by using the isothermal titration calorimetry (ITC) technique supported by potentiometric titration data. The study was concerned with the 2 common tripodal aminocarboxylate ligands, namely, nitrilotriacetic acid and N-(2-hydroxyethyl) iminodiacetic acid. Calorimetric measurements (ITC) were run in the 2-(N-morpholino)ethanesulfonic acid hydrate (2-(N-morpholino) ethanesulfonic acid), piperazine-N,N'-bis(2-ethanesulfonic acid), and dimethylarsenic acid buffers (0.1 mol L -1 , pH 6) at 298.15 K. The quantification of the metal-buffer interactions and their incorporation into the ITC data analysis enabled to obtain the pH-independent and buffer-independent thermodynamic parameters (K, ΔG, ΔH, and ΔS) for the reactions under study. Furthermore, the kinITC method was applied to obtain kinetic information on complexation reactions from the ITC data. Correlations, based on kinetic and thermodynamic data, between the kinetics of formation of Co 2 + and Ni 2 + complexes and their thermodynamic stabilities are discussed. Copyright © 2016 John Wiley & Sons, Ltd.

  7. Analysis of the interactions between human serum albumin/amphiphilic penicillin in different aqueous media: an isothermal titration calorimetry and dynamic light scattering study

    Energy Technology Data Exchange (ETDEWEB)

    Barbosa, Silvia [Grupo de Sistemas Complejos, Laboratorio de Fisica de Coloides y Polimeros, Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain); Taboada, Pablo [Grupo de Sistemas Complejos, Laboratorio de Fisica de Coloides y Polimeros, Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain)]. E-mail: fmpablo@usc.es; Mosquera, Victor [Grupo de Sistemas Complejos, Laboratorio de Fisica de Coloides y Polimeros, Departamento de Fisica de la Materia Condensada, Facultad de Fisica, Universidad de Santiago de Compostela, E-15782 Santiago de Compostela (Spain)

    2005-04-04

    The complexation process of the amphiphilic penicillins sodium cloxacillin and sodium dicloxacillin with the protein human serum albumin (HSA) in aqueous buffered solutions of pH 4.5 and 7.4 at 25 {sup o}C was investigated through isothermal titration calorimetry (ITC) and dynamic light scattering. ITC experiments were carried out in the very dilute regime and showed that although hydrophobic interactions are the leading forces for complexation, electrostatic interactions also play an important role. The possibility of the formation of hydrogen bonds is also deduced from experimental data. The thermodynamic quantities of the binding mechanism, i.e, the enthalpy, {delta}HITCi, entropy, {delta}SITCi, Gibbs energy, {delta}GITCi, binding constant, KITCi and the number of binding sites, n{sub i}, were obtained. The binding was saturable and is characterised by Langmuir adsorption isotherms. From ITC data and following a theoretical model, the number of bound and free penicillin molecules was calculated. From Scatchard plots, KITCi and n{sub i} were obtained and compared with those from ITC data. The interaction potential between the HSA-penicillin complexes and their stability were determined at pH 7.4 from the dependence of the diffusion coefficients on protein concentration by application of the DLVO colloidal stability theory. The results indicate decreasing stability of the colloidal dispersion of the drug-protein complexes with increase in the concentration of added drug.

  8. Analysis of the interactions between human serum albumin/amphiphilic penicillin in different aqueous media: an isothermal titration calorimetry and dynamic light scattering study

    Science.gov (United States)

    Barbosa, Silvia; Taboada, Pablo; Mosquera, Victor

    2005-04-01

    The complexation process of the amphiphilic penicillins sodium cloxacillin and sodium dicloxacillin with the protein human serum albumin (HSA) in aqueous buffered solutions of pH 4.5 and 7.4 at 25 °C was investigated through isothermal titration calorimetry (ITC) and dynamic light scattering. ITC experiments were carried out in the very dilute regime and showed that although hydrophobic interactions are the leading forces for complexation, electrostatic interactions also play an important role. The possibility of the formation of hydrogen bonds is also deduced from experimental data. The thermodynamic quantities of the binding mechanism, i.e, the enthalpy, ΔHITCi, entropy, ΔSITCi, Gibbs energy, ΔGITCi, binding constant, KITCi and the number of binding sites, ni, were obtained. The binding was saturable and is characterised by Langmuir adsorption isotherms. From ITC data and following a theoretical model, the number of bound and free penicillin molecules was calculated. From Scatchard plots, KITCi and ni were obtained and compared with those from ITC data. The interaction potential between the HSA-penicillin complexes and their stability were determined at pH 7.4 from the dependence of the diffusion coefficients on protein concentration by application of the DLVO colloidal stability theory. The results indicate decreasing stability of the colloidal dispersion of the drug-protein complexes with increase in the concentration of added drug.

  9. Calorimetry investigations of milled α-tricalcium phosphate (α-TCP) powders to determine the formation enthalpies of α-TCP and X-ray amorphous tricalcium phosphate.

    Science.gov (United States)

    Hurle, Katrin; Neubauer, Juergen; Bohner, Marc; Doebelin, Nicola; Goetz-Neunhoeffer, Friedlinde

    2015-09-01

    One α-tricalcium phosphate (α-TCP) powder was either calcined at 500°C to obtain fully crystalline α-TCP or milled for different durations to obtain α-TCP powders containing various amounts of X-ray amorphous tricalcium phosphate (ATCP). These powders containing between 0 and 71wt.% ATCP and up to 2.0±0.1wt.% β-TCP as minor phase were then hydrated in 0.1M Na2HPO4 aqueous solution and the resulting heat flows were measured by isothermal calorimetry. Additionally, the evolution of the phase composition during hydration was determined by in situ XRD combined with the G-factor method, an external standard method which facilitates the indirect quantification of amorphous phases. Maximum ATCP hydration was reached after about 1h, while that of crystalline α-TCP hydration occurred between 4 and 11h, depending on the ATCP content. An enthalpy of formation of -4065±6kJ/mol (T=23°C) was calculated for ATCP (Ca3(PO4)2), while for crystalline α-TCP (α-Ca3(PO4)2) a value of -4113±6kJ/mol (T=23°C) was determined. Copyright © 2015 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Non-isothermal crystallization kinetics and glass-forming ability of Ti41Zr25Be28Fe6 bulk metallic glass investigated by differential scanning calorimetry

    Science.gov (United States)

    Gong, Pan; Zhao, Shaofan; Wang, Xin; Yao, Kefu

    2015-07-01

    The non-isothermal crystallization kinetics and glass-forming ability of Ti41Zr25Be28Fe6 glassy alloy were investigated by differential scanning calorimetry. The activation energies corresponding to the characteristic temperatures have been calculated by Kissinger and Ozawa equations. Based on Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall models, it has been found that the local activation energy is higher at the beginning of the crystallization process for the first exothermic peak. The local Avrami exponent indicates that the first-step crystallization is mainly a high-dimensional nucleation and growth with an increasing nucleation rate. According to the calculated fragility index, Ti41Zr25Be28Fe6 alloy can be classified as "strong glass former." The studied alloy also possesses a critical size up to centimeter order, and the high glass-forming ability is probably related to the relatively low Gibbs energy difference between the liquid and crystalline states. The critical cooling rate of Ti41Zr25Be28Fe6 glassy alloy has also been determined using Barandiaran-Colmenero's method.

  11. Kinetics of Cold-Cap Reactions for Vitrification of Nuclear Waste Glass Based on Simultaneous Differential Scanning Calorimetry - Thermogravimetry (DSC-TGA) and Evolved Gas Analysis (EGA)

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez, Carmen P.; Pierce, David A.; Schweiger, Michael J.; Kruger, Albert A.; Chun, Jaehun; Hrma, Pavel R.

    2013-12-03

    For vitrifying nuclear waste glass, the feed, a mixture of waste with glass-forming and modifying additives, is charged onto the cold cap that covers 90-100% of the melt surface. The cold cap consists of a layer of reacting molten glass floating on the surface of the melt in an all-electric, continuous glass melter. As the feed moves through the cold cap, it undergoes chemical reactions and phase transitions through which it is converted to molten glass that moves from the cold cap into the melt pool. The process involves a series of reactions that generate multiple gases and subsequent mass loss and foaming significantly influence the mass and heat transfers. The rate of glass melting, which is greatly influenced by mass and heat transfers, affects the vitrification process and the efficiency of the immobilization of nuclear waste. We studied the cold-cap reactions of a representative waste glass feed using both the simultaneous differential scanning calorimetry thermogravimetry (DSC-TGA) and the thermogravimetry coupled with gas chromatography-mass spectrometer (TGA-GC-MS) as complementary tools to perform evolved gas analysis (EGA). Analyses from DSC-TGA and EGA on the cold-cap reactions provide a key element for the development of an advanced cold-cap model. It also helps to formulate melter feeds for higher production rate.

  12. Energy and Protein in Critically Ill Patients with AKI: A Prospective, Multicenter Observational Study Using Indirect Calorimetry and Protein Catabolic Rate

    Directory of Open Access Journals (Sweden)

    Alice Sabatino

    2017-07-01

    Full Text Available The optimal nutritional support in Acute Kidney Injury (AKI still remains an open issue. The present study was aimed at evaluating the validity of conventional predictive formulas for the calculation of both energy expenditure and protein needs in critically ill patients with AKI. A prospective, multicenter, observational study was conducted on adult patients hospitalized with AKI in three different intensive care units (ICU. Nutrient needs were estimated by different methods: the Guidelines of the European Society of Parenteral and Enteral Nutrition (ESPEN for both calories and proteins, the Harris-Benedict equation, the Penn-State and Faisy-Fagon equations for energy. Actual energy and protein needs were repeatedly measured by indirect calorimetry (IC and protein catabolic rate (PCR until oral nutrition start, hospital discharge or renal function recovery. Forty-two patients with AKI were enrolled, with 130 IC and 123 PCR measurements obtained over 654 days of artificial nutrition. No predictive formula was precise enough, and Bland-Altman plots wide limits of agreement for all equations highlight the potential to under- or overfeed individual patients. Conventional predictive formulas may frequently lead to incorrect energy and protein need estimation. In critically ill patients with AKI an increased risk for under- or overfeeding is likely when nutrient needs are estimated instead of measured.

  13. Evaluation of phenylbutazone and poly(amidoamine) dendrimers interactions by a combination of solubility, 2D-NOESY NMR, and isothermal titration calorimetry studies.

    Science.gov (United States)

    Yang, Wenjun; Li, Yiwen; Cheng, Yiyun; Wu, Qinglin; Wen, Longping; Xu, Tongwen

    2009-03-01

    The interactions between phenylbutazone, a well-established nonsteroidal anti-inflammatory drug, with different generations of poly(amidoamine) (PAMAM) dendrimers, have been investigated by aqueous solubility, two dimensional nuclear Overhauser effect spectroscopy (2D-NOESY) and isothermal titration calorimetry (ITC) studies. Solubility results showed that PAMAM dendrimers significantly enhanced the aqueous solubility of phenylbutazone and the solubilization was much influenced by dendrimer concentration, generation, surface function group and pH value. The 2D-NOESY spectra clearly showed that there were several kinds of cross-peaks from NOE interactions between the protons of phenylbutazone and the protons in interior cavities of both generation 6 and generation 3 PAMAM dendrimers. The solubility, 2D-NOESY results and ITC analysis suggest that encapsulation and electrostatic interaction together caused the solubility enhancement of phenylbutazone. The new techniques such as 2D-NOESY and ITC used in this study are useful tools in investigating the interactions between dendrimers and guest molecules. (c) 2008 Wiley-Liss, Inc. and the American Pharmacists Association

  14. Determination of absorbed dose to water in a clinical carbon ion beam by means of fluorescent nuclear track detectors, ionization chambers, and water calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Osinga-Blaettermann, Julia-Maria

    2016-12-20

    Until now, dosimetry of carbon ions with ionization chambers has not reached the same level of accuracy as of high-energy photons. This is mainly caused by the threefold higher uncertainty of the k{sub Q,Q{sub 0}}-factor of ionization chambers, which is derived by calculations due to a lack of experimental data. The current thesis comprises two major aims with respect to the dosimetry of carbon ion beams: first, the investigation of the potential of fluorescent nuclear track detectors for fluence-based dosimetry and second, the experimental determination of the k{sub Q,Q{sub 0}}-factor. The direct comparison of fluence- and ionization-based measurements has shown a significant discrepancy of 4.5 %, which re-opened the discussion on the accuracy of calculated k{sub Q,Q{sub 0}}-factors. Therefore, absorbed dose to water measurements by means of water calorimetry have been performed allowing for the direct calibration of ionization chambers and thus for the experimental determination of k{sub Q,Q{sub 0}}. For the first time it could be shown that the experimental determination of k{sub Q,Q{sub 0}} for carbon ion beams is achievable with a standard measurement uncertainty of 0.8 %. This corresponds to a threefold reduction of the uncertainty compared to calculated values and therefore enables to significantly decrease the overall uncertainty related to ionization-based dosimetry of clinical carbon ion beams.

  15. Affinity between TBC1D4 (AS160 phosphotyrosine-binding domain and insulin-regulated aminopeptidase cytoplasmic domain measured by isothermal titration calorimetry

    Directory of Open Access Journals (Sweden)

    SangYoun Park*, Keon Young Kim, Sunmin Kim & Young Seok Yu

    2012-06-01

    Full Text Available Uptake of circulating glucose into the cells happens via the insulin-mediated signalling pathway, which translocates the glucosetransporter 4 (GLUT4 vesicles from the intracellular compartmentto the plasma membrane. RabㆍGTPases are involvedin this vesicle trafficking, where RabㆍGTPase-activatingproteins (RabGAP enhance the GTP to GDP hydrolysis.TBC1D4 (AS160 and TBC1D1 are functional RabGAPs in theadipocytes and the skeletonal myocytes, respectively. Theseproteins contain two phosphotyrosine-binding domains (PTBsat the amino-terminus of the catalytic RabGAP domain. Thesecond PTB has been shown to interact with the cytoplasmicregion of the insulin-regulated aminopeptidase (IRAP of theGLUT4 vesicle. In this study, we quantitatively measured the∼μM affinity (KD between TBC1D4 PTB and IRAP using isothermaltitration calorimetry, and further showed that IRAP residues1-49 are the major region mediating this interaction. Wealso demonstrated that the IRAP residues 1-15 are necessarybut not sufficient for the PTB interaction.

  16. Analysis of light particles correlation selected by neutron calorimetry in the reaction {sup 208} Pb+{sup 93} Nb at 29 MeV/u; Analyse de correlation de particules legeres selectionnees par calorimetrie neutronique dans la reaction {sup 208} Pb+{sup 93} Nb a 29 MeV/u

    Energy Technology Data Exchange (ETDEWEB)

    Ghisalberti, C.

    1994-11-10

    This work deals with the analysis of light particles correlation selected by neutrons calorimetry in the reaction : {sup 208} Pb+{sup 93} Nb at 29 MeV/u. In the first part are described the interest of correlation functions, the proton-proton correlation function study, the classical model developed for describing the correlations of two light particles emitted by a nucleus in thermal equilibrium, the quantum model and some notions about exclusive sources and measures. The second part is a description of the experience : {sup 208} Pb+{sup 93} Nb at 29 MeV/u. The analysis of experimental data and of experimental correlation functions are given respectively in the third and the fourth parts. (O.L.). 38 refs., 82 figs., 11 tabs.

  17. The effect of feeding on CO2 production and energy expenditure in ponies measured by indirect calorimetry and the 13C-bicarbonate technique

    DEFF Research Database (Denmark)

    Jensen, Rasmus Bovbjerg; Kyrstein, T. D.; Junghans, P

    2015-01-01

    Energy expenditure (EE) can be estimated based on respiratory gas exchange measurements, traditionally done in respiration chambers by indirect calorimetry (IC). However, the (13)C-bicarbonate technique ((13)C-BT) might be an alternative minimal invasive method for estimation of CO(2) production ...... in future studies with horses to avoid complex (13)C enrichment-time curves with maxima and shoulders as observed in several experiments with oral administration of (13)C-bicarbonate....

  18. Compatibilidad química del piracetam determinada por calorimetría diferencial de barrido Chemical compatibility of piracetam determined by differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Luis Octavio Martínez Álvarez

    2013-03-01

    Full Text Available Introducción: en la primera etapa de preformulación de un medicamento se seleccionan los excipientes y es importante la realización de los estudios de compatibilidad química entre el ingrediente activo farmacéutico (IFA y excipientes. Una de las técnicas más rápidas para realizar dichos estudios es la Calorimetría diferencial de barrido (DSC, y como técnica complementaria la Termogravimetría (TG. Objetivo: empleando DSC y TG, se realiza un estudio de compatibilidad química entre IFA y excipientes preseleccionados, para comprobar la existencia o no de interacción química. Métodos: el equipo empleado fue el TA3000Mettler, aco­plado a la celda DSC20 y al horno TG50. El IFA utilizado fue Piracetam, y los excipientes: Kollidon VA 64, Estearato de magnesio, Celulosa microcristalina, Polietilenglicol 20 000 y Aerosil. Dichos excipientes se caracterizaron por DSC al igual que el IFA, al cual se le detectó la transición física de fusión. Para el estudio de compatibilidad se prepararon mezclas físicas binarias en una relación de concentración 1:1 Resultados: la figura 1 muestra la detección del punto de fusión por DSC del IFA. Se obtuvieron dos transiciones endotérmicas, comprobándose por TG cuál era la de fusión. La figura 2 muestra los termogramas de las mezclas formadas entre IFA y excipientes. Conclusiones: no se detectó aparición de nuevos picos, por lo que se infiere que no hay incompatibilidad química entre las sustancias estudiadas y se recomienda el uso de los excipientes para el desarrollo de la formulación farmacéutica.Introduction: the first phase of the drug preformulation comprises the selection of excipients and the conduction of studies on chemical compatibility between pharmacologically active ingredient and the excipients. One of the quickest techniques is the differential scanning calorimetry and the supplementary technique called thermogravimetic analysis. Objective: to conduct a chemical compatibility

  19. Studies of inclusion complexes between cyclodextrins and polyazamacrocyclic chelates of lanthanide (III) ions[Binding equilibria; Titration calorimetry; Molecular dynamics; Lanthanide (III) chelates of polyazamacrocycles; {gamma}-Cyclodextrin

    Energy Technology Data Exchange (ETDEWEB)

    Henriques, Elsa S.; Bastos, Margarida E-mail: mbastos@fc.up.pt; Geraldes, Carlos F.G.C.; Ramos, Maria Joao

    2003-10-01

    The complexes between {gamma}-cyclodextrin and lanthanide (III) chelates of the polyazamacrocycles DOTA (DOTA {identical_to} 1,4,7,10-tertraazacyclododecane-1,4,7,10-tetraacetate) and DOTP (DOTP {identical_to} 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetramethylenephosphonate) have been thought out to enhance the potential of such chelates as contrast agents for MRI. Given the actual demand for the design of new contrast agents, we thought it worthwhile to confirm previous results for the equilibrium constant K obtained by one of us by NMR on the DOTP complex, as well as to determine K for a new one with DOTA. Further, we wanted to study and quantify the interactions present in these complexes, with a view to improve them in newly designed complexes. The interactions between {gamma}-cyclodextrin and the lanthanide (III)-polyazamacrocyclic chelates, [Tm(DOTP)]{sup 5-}, and [Gd(DOTA)]{sup -} were then studied by isothermal calorimetry (ITC) and molecular dynamics. The calorimetric experiments can be interpreted by considering that in both cases there is a weak association, characterized by low values for the equilibrium constant as well as for the molar enthalpy change for complex formation, at T=298.15 K. The K value for the complex with DOTP obtained now by ITC is of the same order of magnitude of the one determined previously by NMR. Further, the complex formation seems rather insensitive to the macrocycle, as the values now obtained by ITC for the DOTA complex are very similar to the ones obtained for the DOTP complex. We have also carried out molecular dynamics simulations on these very same inclusion complexes, which provided quantitative data on the interactions present, as well as a plausible explanation for the data obtained, leading to the proposal of possible solutions to improve the modelling of new contrast agents on a host-guest basis.

  20. Origin and Formation Mechanism Investigation of Compound Precipitation from the Traditional Chinese Prescription Huang-Lian-Jie-Du-Tang by Isothermal Titration Calorimetry.

    Science.gov (United States)

    Wang, Hui; Li, Tong; Xiang, Hongjun; Zhang, Xinyu; Fang, Kang; Wu, Gaorong; Yan, Mengmeng; Xue, Nannan; Chen, Meng; Xie, Tianxin; Zhang, Yuzhong; Wang, Penglong; Lei, Haimin

    2017-09-01

    Previous studies have shown that compounds in the form of precipitate (CFP) from Huang-Lian-Jie-Du-Tang (HLJDT) were stable, and the CFP content reached 2.63% of the whole decoction and had good neuroprotective effects. However, there has been no research on their specific source. In this study, it was found that HLJDT CFP mainly came from the reaction of Scutellaria baicalensis and Coptis chinensis by studying the separated prescription components (accounting for 81.33% of HLJDT CFP). Unlike previous studies on HLJDT CFP, in this research the chemical composition of Scutellaria baicalensis-Coptis chinensis (SB-CC) CFP was identified by high performance liquid chromatography coupled with mass spectrometry (HPLC-MSn), which further proved that the main source of HLJDT CFP was Scutellaria baicalensis-Coptis chinensis CFP compared with previous HLJDT CFP studies. To explain the reaction mechanism between the decoctions of Scutellaria baicalensis and Coptis chinensis, isothermal titration calorimetry (ITC) was used to analyze their binding heat and the thermodynamic parameters (ΔH, ΔS, ΔG, n, Ka) of the reaction between baicalin and berberine, which are the main components of Scutellaria baicalensis and Coptis chinensis, respectively. The results showed that the reaction between decoctions of Scutellaria baicalensis and Coptis chinensis was exothermic and the reaction between baicalin and berberine was a spontaneous and enthalpy-driven chemical reaction, the binding ratio being 1:1. In addition, HLJDT CFP (EC50 = 14.71 ± 0.91 µg/mL) and SB-CC CFP (EC50 = 6.11 ± 0.12 µg/mL) showed similar protective activities on PC12 cells injured by cobalt chloride (CoCl₂). This study provided a new angle to research on the main chemical components and therapeutic values of CFP in Traditional Chinese Medicine compounds.

  1. Probing the interaction of lysozyme with ciprofloxacin in the presence of different-sized Ag nano-particles by multispectroscopic techniques and isothermal titration calorimetry.

    Science.gov (United States)

    Pasban Ziyarat, Fatemeh; Asoodeh, Ahmad; Sharif Barfeh, Zahra; Pirouzi, Maliheh; Chamani, Jamshidkhan

    2014-04-01

    The binding of ciprofloxacin to lysozyme in the presence of three Ag nano-particles of varying sizes was for the first time investigated by multispectroscopic and isothermal titration calorimetry techniques at pH 7.4. The results indicated that ciprofloxacin quenched the fluorescence intensity of lysozyme through a static mechanism but in the presence of size-II Ag nano-particles, there were two kinds of interaction behaviors. The interaction between ciprofloxacin and lysozyme occurred via a second type of binding site, whereas in the presence of the Ag nano-particles, some changes occurred. The secondary structure of lysozyme-ciprofloxacin in the presence of Ag nano-particles was determined by circular dichroism. The thermodynamic parameters of the interaction between ciprofloxacin and lysozyme in the presence of Ag nano-particles were measured according to the van't Hoff equation. The enthalpy (ΔH(○)) and entropy (ΔS(○)) changes were calculated to be -49.7 (kJ mol(-1)) and -20.1 (J mol(-1) K(-1)), respectively, which indicated that the interaction of ciprofloxacin with lysozyme was driven mainly by van der Waals forces and hydrogen bonding. In the presence of the three different-sized Ag nano-particles, the enthalpic and the entropic changes were both negative which indicated that hydrogen bonding with van der Waals forces played major roles in the binding between ciprofloxacin and lysozyme. Recent developments in nano-materials offer new pathways for controlling the protein behavior through surface interactions. These data indicate that the recent research on nano-particle/protein interactions will emphasize the importance of such interactions in biological systems with applications including the diagnosis and treatment of human diseases.

  2. Continuous gradient temperature Raman spectroscopy and differential scanning calorimetry of N-3DPA and DHA from -100 to 10°C.

    Science.gov (United States)

    Broadhurst, C Leigh; Schmidt, Walter F; Nguyen, Julie K; Qin, Jianwei; Chao, Kuanglin; Aubuchon, Steven R; Kim, Moon S

    2017-04-01

    Docosahexaenoic acid (DHA, 22:6n-3) is exclusively utilized in fast signal processing tissues such as retinal, neural and cardiac. N-3 docosapentaenoic acid (n-3DPA, 22:5n-3), with just one less double bond, is also found in the marine food chain yet cannot substitute for DHA. Gradient temperature Raman spectroscopy (GTRS) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur near and at phase transitions. Herein we apply GTRS and both conventional and modulated DSC to n-3DPA and DHA from -100 to 20°C. Three-dimensional data arrays with 0.2°C increments and first derivatives allowed complete assignment of solid, liquid and transition state vibrational modes. Melting temperatures n-3DPA (-45°C) and DHA (-46°C) are similar and show evidence for solid-state phase transitions not seen in n-6DPA (-27°C melt). The C6H2 site is an elastic marker for temperature perturbation of all three lipids, each of which has a distinct three dimensional structure. N-3 DPA shows the spectroscopic signature of saturated fatty acids from C1 to C6. DHA does not have three aliphatic carbons in sequence; n-6DPA does but they occur at the methyl end, and do not yield the characteristic signal. DHA appears to have uniform twisting from C6H2 to C12H2 to C18H2 whereas n-6DPA bends from C12 to C18, centered at C15H2. For n-3DPA, twisting is centered at C6H2 adjacent to the C2-C3-C4-C5 aliphatic moiety. These molecular sites are the most elastic in the solid phase and during premelting. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Physical properties of archaeal tetraether lipid membranes as revealed by differential scanning and pressure perturbation calorimetry, molecular acoustics, and neutron reflectometry: effects of pressure and cell growth temperature.

    Science.gov (United States)

    Zhai, Yong; Chong, Parkson Lee-Gau; Taylor, Leeandrew Jacques-Asa; Erlkamp, Mirko; Grobelny, Sebastian; Czeslik, Claus; Watkins, Erik; Winter, Roland

    2012-03-20

    The polar lipid fraction E (PLFE) is a major tetraether lipid component in the thermoacidophilic archaeon Sulfolobus acidocaldarius. Using differential scanning and pressure perturbation calorimetry as well as ultrasound velocity and density measurements, we have determined the compressibilities and volume fluctuations of PLFE liposomes derived from different cell growth temperatures (T(g) = 68, 76, and 81 °C). The compressibility and volume fluctuation values of PLFE liposomes, which are substantially less than those detected from diester lipid membranes (e.g., DPPC), exhibit small but significant differences with T(g). Among the three T(g)s employed, 76 °C leads to the least compressible and most tightly packed PLFE membranes. This temperature is within the range for optimal cell growth (75-80 °C). It is known that a decrease in T(g) decreases the number of cyclopentane rings in archael tetraether lipids. Thus, our data enable us to present the new view that membrane packing in PLFE liposomes varies with the number of cyclopentane rings in a nonlinear manner, reaching maximal tightness when the tetraether lipids are derived from cells grown at optimal T(g)s. In addition, we have studied the effects of pressure on total layer thickness, d, and neutron scattering length density, ρ(n), of a silicon-D(2)O interface that is covered with a PLFE membrane using neutron reflectometry (NR). At 55 °C, d and ρ(n) are found to be rather insensitive to pressure up to 1800 bar, suggesting minor changes of the thickness of the membrane's hydrophobic core and headgroup orientation upon compression only.

  4. Reversible amorphous-crystalline phase changes in a wide range of Se(1-x)Te(x) alloys studied using ultrafast differential scanning calorimetry.

    Science.gov (United States)

    Vermeulen, Paul A; Momand, Jamo; Kooi, Bart J

    2014-07-14

    The reversible amorphous-crystalline phase change in a chalcogenide material, specifically the Se1-xTex alloy, has been investigated for the first time using ultrafast differential scanning calorimetry. Heating rates and cooling rates up to 5000 K/s were used. Repeated reversible amorphous-crystalline phase switching was achieved by consecutively melting, melt-quenching, and recrystallizing upon heating. Using a well-conditioned method, the composition of a single sample was allowed to shift slowly from 15 at. %Te to 60 at. %Te, eliminating sample-to-sample variability from the measurements. Using Energy Dispersive X-ray Spectroscopy composition analysis, the onset of melting for different Te-concentrations was confirmed to coincide with the literature solidus line, validating the use of the onset of melting Tm as a composition indicator. The glass transition Tg and crystallization temperature Tc could be determined accurately, allowing the construction of extended phase diagrams. It was found that Tm and Tg increase (but Tg/Tm decrease slightly) with increasing Te-concentration. Contrarily, the Tc decreases substantially, indicating that the amorphous phase becomes progressively unfavorable. This coincides well with the observation that the critical quench rate to prevent crystallization increases about three orders of magnitude with increasing Te concentration. Due to the employment of a large range of heating rates, non-Arrhenius behavior was detected, indicating that the undercooled liquid SeTe is a fragile liquid. The activation energy of crystallization was found to increase 0.5-0.6 eV when the Te concentration increases from 15 to 30 at. % Te, but it ceases to increase when approaching 50 at. % Te.

  5. Basal Metabolic Rate of Adolescent Modern Pentathlon Athletes: Agreement between Indirect Calorimetry and Predictive Equations and the Correlation with Body Parameters.

    Directory of Open Access Journals (Sweden)

    Luiz Lannes Loureiro

    Full Text Available The accurate estimative of energy needs is crucial for an optimal physical performance among athletes and the basal metabolic rate (BMR equations often are not well adjusted for adolescent athletes requiring the use of specific methods, such as the golden standard indirect calorimetry (IC. Therefore, we had the aim to analyse the agreement between the BMR of adolescents pentathletes measured by IC and estimated by commonly used predictive equations.Twenty-eight athletes (17 males and 11 females were evaluated for BMR, using IC and the predictive equations Harris and Benedict (HB, Cunningham (CUN, Henry and Rees (HR and FAO/WHO/UNU (FAO. Body composition was obtained using DXA and sexual maturity data were retrieved through validated questionnaires. The correlations among anthropometric variables an IC were analysed by T-student test and ICC, while the agreement between IC and the predictive equations was analysed according to Bland and Altman and by survival-agreement plotting.The whole sample average BMR measured by IC was significantly different from the estimated by FAO (p<0.05. Adjusting data by gender FAO and HR equations were statistically different from IC (p <0.05 among males, while female differed only for the HR equation (p <0.05.The FAO equation underestimated athletes' BMR when compared with IC (T Test. When compared to the golden standard IC, using Bland and Altman, ICC and Survival-Agreement, the equations underestimated the energy needs of adolescent pentathlon athletes up to 300kcal/day. Therefore, they should be used with caution when estimating individual energy requirements in such populations.

  6. Enthalpy Changes during Photosynthetic Water Oxidation Tracked by Time-Resolved Calorimetry Using a Photothermal Beam Deflection Technique☆☆☆

    Science.gov (United States)

    Krivanek, Roland; Dau, Holger; Haumann, Michael

    2008-01-01

    The energetics of the individual reaction steps in the catalytic cycle of photosynthetic water oxidation at the Mn4Ca complex of photosystem II (PSII) are of prime interest. We studied the electron transfer reactions in oxygen-evolving PSII membrane particles from spinach by a photothermal beam deflection technique, allowing for time-resolved calorimetry in the micro- to millisecond domain. For an ideal quantum yield of 100%, the enthalpy change, ΔH, coupled to the formation of the radical pair YZ⋅+QA− (where YZ is Tyr-161 of the D1 subunit of PSII) is estimated as −820 ± 250 meV. For a lower quantum yield of 70%, the enthalpy change is estimated to be −400 ± 250 meV. The observed nonthermal signal possibly is due to a contraction of the PSII protein volume (apparent ΔV of about −13 Å3). For the first time, the enthalpy change of the O2-evolving transition of the S-state cycle was monitored directly. Surprisingly, the reaction is only slightly exergonic. A value of ΔH(S3 ⇒ S0) of −210 meV is estimated, but also an enthalpy change of zero is within the error range. A prominent nonthermal photothermal beam deflection signal (apparent ΔV of about +42 Å3) may reflect O2 and proton release from the manganese complex, but also reorganization of the protein matrix. PMID:17993488

  7. Crystallization kinetics of Fe-B based amorphous alloys studied in-situ using X-rays diffraction and differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Santos D.R. dos

    2001-01-01

    Full Text Available The crystallization processes for the amorphous metallic alloys Fe74B17Si2Ni4Mo3 and Fe86B6Zr7Cu1 (at. % were investigated using X-rays diffraction measurements performed in-situ during Joule-heating, with simultaneous monitoring of the electrical resistance. We determined the main structural transitions and crystalline phases formed during heating, and correlated these results to the observed resistance variations. As the annealing current is increased, the resistance shows an initial decrease due to stress relaxation, followed by a drop to a minimum value due to massive nucleation and growth of alpha-Fe nanocrystals. Further annealing causes the formation of small fractions of Fe-B, B2Zr or ZrO2, while the resistance increases due to temperature enhancement. In situ XRD measurements allowed the identification of metastable phases, as the gamma-Fe phase which occurs at high temperatures. The exothermal peaks observed in the differential scanning calorimetry (DSC for each alloy corroborate the results. We also have performed DSC measurements with several heating rates, which allowed the determination of the Avrami exponent and crystallization activation energy for each alloy. The obtained activation energies (362 and 301 kJ/mol for Fe-B-Zr-Cu; 323 kJ/mol for Fe-B-Si-Ni-Mo are comparable to reported values for amorphous iron alloys, while the Avrami exponent values (n = 1.0 or n = 1.2 are consistent with diffusion controlled crystallization processes with nucleation rates close to zero.

  8. The effect of feeding on CO2 production and energy expenditure in ponies measured by indirect calorimetry and the 13C-bicarbonate technique.

    Science.gov (United States)

    Jensen, R B; Kyrstein, T D; Junghans, P; Tauson, A H

    2015-11-01

    Energy expenditure (EE) can be estimated based on respiratory gas exchange measurements, traditionally done in respiration chambers by indirect calorimetry (IC). However, the (13)C-bicarbonate technique ((13)C-BT) might be an alternative minimal invasive method for estimation of CO(2) production and EE in the field. In this study, four Shetland ponies were used to explore the effect of feeding on CO(2) production and EE measured simultaneously by IC and (13)C-BT. The ponies were individually housed in respiration chambers and received either a single oral or intravenous (IV) bolus dose of (13)C-labelled sodium bicarbonate (NaH(13)CO(3)). The ponies were fed haylage 3 h before (T(-3)), simultaneously with (T(0)) or 3 h after (T(+3)) administration of (13)C-bicarbonate. The CO(2) produced and O(2) consumed by the ponies were measured for 6 h with both administration routes of (13)C-bicarbonate at the three different feeding times. Feeding time affected the CO(2) production (Pproduction measured by 13C-BT. An average RQ was used for the calculations of EE. There was no difference between IC and (13)C-BT for estimation of CO(2) production. An effect of feeding time (Pproduction and EE. This should be considered when the (13)C-BT is used in the field. IV administration of (13)C-bicarbonate is recommended in future studies with horses to avoid complex (13)C enrichment-time curves with maxima and shoulders as observed in several experiments with oral administration of (13)C-bicarbonate.

  9. Experimental measurements of the heats of formation of Fe{sub 3}Pt, FePt, and FePt{sub 3} using differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Wang, B.; Berry, D. C.; Chiari, Y.; Barmak, K. [Department of Materials Science and Engineering and the Data Storage Systems Center, Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, Pennsylvania 15213 (United States)

    2011-07-01

    Using differential scanning calorimetry (DSC), the heats of formation of Fe{sub 3}Pt, FePt, and FePt{sub 3} were determined from the reaction of sputter deposited Fe/Pt multilayer thin-films with a periodicity of 200 nm but different overall compositions. Film compositions were measured by energy dispersive x-ray spectrometry. The phases present along the reaction path were identified by x-ray diffraction. For the most Fe-rich phase, namely, Fe{sub 3}Pt, the measured enthalpy of formation was -9.3 {+-} 1.3 kJ/mol in a film with a composition of 70.4:29.6 ({+-}0.2 at. %) Fe:Pt. For FePt, the measured enthalpy of formation was -27.2 {+-} 2.2 kJ/g-atom in a 49.0:51.0 ({+-}0.5 at. %) Fe:Pt film. For FePt{sub 3}, which is the most Pt rich intermetallic phase, the measured enthalpy of formation was -23.7 {+-} 2.2 in a film with a composition of 22.2:77.8 ({+-}0.6 at. %) Fe:Pt. The reaction enthalpies for films with Fe:Pt compositions of 44.5:55.5 ({+-}0.3 at. %) and 38.5:61.5 ({+-}0.4 at. %) were -26.9 {+-} 1.0 and -26.6 {+-} 0.6 kJ/g-atom, respectively, which taken together with the value for the 49.0:51.0 film demonstrate the relative insensitivity of the reaction enthalpy to film composition over a broad composition range in the vicinity of the equiatomic composition. The experimental heats of formation are compared with two sets of reported first-principles calculated values for each of the three phases at exact stoichiometry.

  10. Characterization of the 1st and 2nd EF-hands of NADPH oxidase 5 by fluorescence, isothermal titration calorimetry, and circular dichroism

    Directory of Open Access Journals (Sweden)

    Wei Chin-Chuan

    2012-04-01

    Full Text Available Abstract Background Superoxide generated by non-phagocytic NADPH oxidases (NOXs is of growing importance for physiology and pathobiology. The calcium binding domain (CaBD of NOX5 contains four EF-hands, each binding one calcium ion. To better understand the metal binding properties of the 1st and 2nd EF-hands, we characterized the N-terminal half of CaBD (NCaBD and its calcium-binding knockout mutants. Results The isothermal titration calorimetry measurement for NCaBD reveals that the calcium binding of two EF-hands are loosely associated with each other and can be treated as independent binding events. However, the Ca2+ binding studies on NCaBD(E31Q and NCaBD(E63Q showed their binding constants to be 6.5 × 105 and 5.0 × 102 M-1 with ΔHs of -14 and -4 kJ/mol, respectively, suggesting that intrinsic calcium binding for the 1st non-canonical EF-hand is largely enhanced by the binding of Ca2+ to the 2nd canonical EF-hand. The fluorescence quenching and CD spectra support a conformational change upon Ca2+ binding, which changes Trp residues toward a more non-polar and exposed environment and also increases its α-helix secondary structure content. All measurements exclude Mg2+-binding in NCaBD. Conclusions We demonstrated that the 1st non-canonical EF-hand of NOX5 has very weak Ca2+ binding affinity compared with the 2nd canonical EF-hand. Both EF-hands interact with each other in a cooperative manner to enhance their Ca2+ binding affinity. Our characterization reveals that the two EF-hands in the N-terminal NOX5 are Ca2+ specific. Graphical abstract

  11. Warm liquid calorimetry for LHC

    CERN Document Server

    Geulig,E; Wallraff,W; Bézaguet, Alain-Arthur; Cavanna, F; Cinnini, P; Cittolin, Sergio; Dreesen, P; Demoulin, M; Dunps, L; Fucci, A; Gallay, G; Givernaud, Alain; Gonidec, A; Jank, Werner; Maurin, Guy; Placci, Alfredo; Porte, J P; Radermacher, E; Samyn, D; Schinzel, D; Schmidt, W F; CERN. Geneva. Detector Research and Development Committee

    1990-01-01

    Results from the beam tests of the U/TMP "warm liquid" calorimeter show that such a technique is very promising for the LHC. Our aim is to extend this programme and design a calorimeter that can satisfy the requirements of high rates, high radiation levels, compensation, uniformity and granularity, as well as fully contain hadronic showers. We propose to construct liquid ionization chambers operated at very high fields, capable of collecting the total charge produced by ionizing particles within times comparable to the bunch crossing time of the future Collider. For this reason we plan to extend the current programme on tetramethylpentane (TMP) to tetramethylsilane (TMSi). An electromagnetic calorimeter consisting of very high field ionization chambers filled with TMSi as sensitive medium with Uranium and/or other high density material as absorber will first be built (to be followed by a full-scale calorimeter module), on which newly designed fast amplifiers and readout electronics will be tested. In addition...

  12. Measuring melting capacity with calorimetry

    OpenAIRE

    Betten, Linda

    2014-01-01

    Road salting is an important aspect of winter maintenance. There has been an increase in the usage of salt in later years to keep the road safe and accessible. It is a desire to reduce the amount of salt due to environmental aspects. To achieve better practices for winter maintenance it is necessary to obtain more knowledge about the different properties of salt. The motivation for this thesis is to develop a better method for determining the melting capacity for salt, which is an important p...

  13. SIMULATIONS OF GAMMA-RAY BURST JETS IN A STRATIFIED EXTERNAL MEDIUM: DYNAMICS, AFTERGLOW LIGHT CURVES, JET BREAKS, AND RADIO CALORIMETRY

    Energy Technology Data Exchange (ETDEWEB)

    De Colle, Fabio; Ramirez-Ruiz, Enrico [TASC, Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); Granot, Jonathan [Racah Institute of Physics, The Hebrew University, Jerusalem 91904 (Israel); Lopez-Camara, Diego, E-mail: fabio@ucolick.org [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Ap. 70-543, 04510 D.F. (Mexico)

    2012-05-20

    in a clear bump-like feature in the light curve. However, for larger k values the jet decelerates more gradually, causing only a mild flattening in the radio light curve that might be hard to discern when k = 2. Late-time radio calorimetry, which makes use of a spherical flow approximation near the non-relativistic transition, is likely to consistently overestimate the true energy by up to a factor of a few for k = 2, but likely to either overpredict or underpredict it by a smaller factor for k = 0, 1.

  14. Non-isothermal crystallization kinetic study on Ga{sub 15}Se{sub 85-x}Ag{sub x} chalcogenide glasses by using differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Al-Ghamdi, A.A.; Alvi, M.A. [Department of Physics, King Abdul Aziz University, Jeddah 21589 (Saudi Arabia); Khan, Shamshad A., E-mail: shamshad_phys@yahoo.com [Department of Physics, King Abdul Aziz University, Jeddah 21589 (Saudi Arabia)

    2011-02-03

    Research highlights: > The Ag doped chalcogenide glasses can be used as optical memory, materials for holography and also be used as sensitive electrochemical electrodes or their membranes for sensors for potentiometric determination. > On the basis of the obtained experimental data, the temperature difference (T{sub c} - T{sub g}) and the enthalpy released ({Delta}H{sub c}) are found to be maximum and minimum, respectively, for Ga{sub 15}Se{sub 77}Ag{sub 8} glass, which indicate that this glass is thermally most stable in the composition range under investigation. > In our study volume nucleation with two dimensional growth is responsible during amorphous-crystallization phase transformation. > The speed of rate of crystallization, is faster with Ag at 8% in the present system. > It is observed that Ga{sub 10}Se{sub 90} has a larger probability to jump to a state of lower configurationally energy. - Abstract: At different heating rates, the glass transition temperature (T{sub g}) and the crystallization temperature (T{sub c}) are obtained from the non-isothermal differential scanning calorimetry (DSC) measurements of bulk Ga{sub 15}Se{sub 85-x}Ag{sub x} (x = 0, 2, 4, 6 and 8) chalcogenide glasses prepared by melt quenching technique. Their amorphous state was verified by using X-ray diffraction (XRD) and scanning electron microscopy (SEM). It was observed that the glass transition temperature and crystallization temperatures both increase with increasing heating rates and also by increasing Ag concentration in Ga-Se system. The activation energy of crystallization (E{sub c}), activation energy of glass transition (E{sub g}), crystallization enthalpy ({Delta}H{sub c}) and the Avrami exponent (n) have been determined from the dependence of T{sub g} and T{sub c} on the heating rate ({beta}). The obtained value of the n indicates that the volume nucleation with two dimensional growth is responsible for amorphous-crystallization phase transformation. On the basis of

  15. Simulations of Gamma-Ray Burst Jets in a Stratified External Medium: Dynamics, Afterglow Light Curves, Jet Breaks, and Radio Calorimetry

    Science.gov (United States)

    De Colle, Fabio; Ramirez-Ruiz, Enrico; Granot, Jonathan; Lopez-Camara, Diego

    2012-05-01

    gradually, causing only a mild flattening in the radio light curve that might be hard to discern when k = 2. Late-time radio calorimetry, which makes use of a spherical flow approximation near the non-relativistic transition, is likely to consistently overestimate the true energy by up to a factor of a few for k = 2, but likely to either overpredict or underpredict it by a smaller factor for k = 0, 1.

  16. Characterization of early-age hydration processes in lime-ceramic binders using isothermal calorimetry, X-ray diffraction and scanning electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jerman, Miloš; Tydlitát, Vratislav; Keppert, Martin; Čáchová, Monika; Černý, Robert, E-mail: cernyr@fsv.cvut.cz

    2016-06-10

    Highlights: • Early age hydration processes in lime-ceramic binders are analyzed within a wide range of component ratios. • The applied waste ceramic dust exhibits partial hydraulic properties, ettringite and calcite are formed. • Transition from tobermorite- to jennite-like structures is identified by SEM within the first 48 h. • The highest specific hydration heat after 300 h, 63 J/g, is measured for the binder containing 70% ceramic. • Substantial effect of the heat of wetting is observed, ranging from 10 J/g for lime to 3.9 J/g for ceramic. - Abstract: Early-age hydration processes in a lime-ceramic-water system are analyzed within the whole range of possible lime/ceramic ratios. The isothermal calorimetry shows a substantial effect of the heat of wetting on the total heat evolved, ranging from 10 J/g for lime to 3.9 J/g for ceramic. The highest specific hydration heat of 63 J/g during the analyzed 300-h hydration period exhibits the blended binder containing 70% ceramic and 30% lime which correlates well with the highest compressive and bending strengths of the paste prepared using this blend. Portlandite, ettringite and calcite are the main phases identified by the X-ray diffraction analysis after the hydration of ceramic-rich blends. According to the results of scanning electron microscopy, the initial course of pozzolanic reaction is for this type of binders characterized by the transition from tobermorite-like calcium-silicate-hydrate structures into jennite-like structures within the first 48 h. Blends with the ceramic content lower than 70% show a high portion of portlandite, calcite is present in low amount, and the jennite-like structures are observed after 48 h, following the initial formation of components with a very high Ca content. The favorable properties of the ceramic-rich blended binders can be explained by the partial hydraulic character of the ceramic. With the specific hydration heat of 29 J/g after 300 h and compressive strength

  17. Ionic molecular interactions in solutions of cadmium salts in N-methylpyrrolidone in the presence of ions of alkaline-earth metals, determined using data from calorimetry and densimetry

    Science.gov (United States)

    Novikov, A. N.; Rassokhina, L. Yu.

    2017-10-01

    The heat capacities and densities of three-component solutions NaI-CdI2- N-methylpyrrolidone (NMP), KI-CdI2-NMP, RbI-CdI2-NMP, BaI2-CdI2-NMP, NaNO3-Cd(NO3)2-NMP at 298.15 K are investigated via calorimetry and densimetry. The values of the heat capacities and volumes upon the formation of three-component systems from binary solutions are calculated and discussed. It was established for all of the investigated systems that their deviations from additivity are due to the predominance of processes of acido complex formation.

  18. High-temperature investigations of the rare earth NZP phosphates R {sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} (R = La, Nd, Eu, Lu) by drop calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bykov, D.M. [Chemical Department, Nizhni Novgorod State University, Gagarin Ave. 23, 603950 Nizhni Novgorod (Russian Federation) and European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany)]. E-mail: denis.bykov@inbox.ru; Konings, R.J.M. [European Commission, Joint Research Centre, Institute for Transuranium Elements, P.O. Box 2340, D-76125 Karlsruhe (Germany); Orlova, A.I. [Chemical Department, Nizhni Novgorod State University, Gagarin Ave. 23, 603950 Nizhni Novgorod (Russian Federation)

    2007-07-31

    The high-temperature enthalpy increments of the phosphates La{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3}, Nd{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3}, Eu{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} and Lu{sub 1/3}Zr{sub 2}(PO{sub 4}){sub 3} have been measured by high-temperature drop calorimetry in the temperature range 484.5-1090.7 K. From these results the heat capacity of the studied compounds has been derived.

  19. Search for the scalar partner of the top quark and contribution to the improvement of the calorimetry of the experiment D zero for the phase 2 of Tevatron; Recherche du partenaire supersymetrique du quark top et contribution a l'amelioration de la calorimetrie de l'experience D zero pour la phase 2 du tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Olivier, B

    2001-04-01

    Supersymmetry could be the most natural extension of the Standard Model. In this thesis we present a new search for the sTop, the hypothetical scalar partner of the Top quark, that we performed in the framework of the Minimal Supersymmetric Standard Model (MSSM), using the Run I data of the DO experiment, which corresponds to an integrated luminosity of 108 pb{sup -1}. We selected events with one electron, one muon and missing transverse energy in the final state, which can be the decay product of pair of sTop quarks in 3 (t-tilde {yields} bl{nu}-tilde), or 4-body (t-tilde {yields} b{chi}-tilde{sub 1}{sup 0}l{nu}{sub l}). No signal is seen and the results are interpreted in terms of limits on the sTop production cross-section and exclusion regions in the parameter space (m{sub t}-tilde,m{sub {chi}}-tilde{sub 1{sup 0}}) or (m{sub t}-tilde,m{sub {nu}}-tilde). This new type of selection at the Tevatron for the search of the sTop allowed us to put stronger constraints than those previously published at LEP or at the Tevatron in the t-tilde {yields} bl{nu}-tilde channel, and the first limits ever set in the 4-body decay channel. For the 3-body channel, assuming that the sneutrino is the lightest supersymmetric particle (LSP), the excluded region at 95% confidence level extends up to a sTop mass of 142 (130) GeV if the sneutrino mass (m{sub {nu}}-tilde) is 43 (86) GeV. If the 4-body decay channel dominates, assuming that the neutralino is the LSP, the limit depends on the sneutrino mass. If it is light enough (m{sub {nu}}-tilde {approx}< 100 GeV) this limit reaches a sTop mass of 132 GeV for a neutralino mass of 60 GeV. In all searches for new particles, the calorimetry plays a crucial role from the experimental point of view. The expected increase in integrated luminosity in the Run II which started on the 1. of March 2001, and the detector upgrade which has been achieved over the last three years will allow to extend these exclusion domains or to discover the sTop. We

  20. A comparative study of surface energies and water adsorption on Ce-bastnäsite, La-bastnäsite, and calcite via density functional theory and water adsorption calorimetry.

    Science.gov (United States)

    Goverapet Srinivasan, Sriram; Shivaramaiah, Radha; Kent, Paul R C; Stack, Andrew G; Riman, Richard; Anderko, Andre; Navrotsky, Alexandra; Bryantsev, Vyacheslav S

    2017-03-15

    Bastnäsite, a fluoro-carbonate mineral, is the single largest mineral source of light rare earth elements (REE), La, Ce and Nd. Enhancing the efficiency of separation of the mineral from gangue through froth flotation is the first step towards meeting an ever increasing demand for REE. To design and evaluate collector molecules that selectively bind to bastnäsite, a fundamental understanding of the structure and surface properties of bastnäsite is essential. In our earlier work (J. Phys. Chem. C, 2016, 120, 16767), we carried out an extensive study of the structure, surface stability and water adsorption energies of La-bastnäsite. In this work, we make a comparative study of the surface properties of Ce-bastnäsite, La-bastnäsite, and calcite using a combination of density functional theory (DFT) and water adsorption calorimetry. Spin polarized DFT+U calculations show that the exchange interaction between the electrons in Ce 4f orbitals is negligible and that these orbitals do not participate in bonding with the oxygen atom of the adsorbed water molecule. In agreement with calorimetry, DFT calculations predict larger surface energies and stronger water adsorption energies on Ce-bastnäsite than on La-bastnäsite. The order of stabilities for stoichiometric surfaces is as follows: [101[combining macron]0] > [101[combining macron]1] > [101[combining macron]2] > [0001] > [112[combining macron]2] > [101[combining macron]4] and the most favorable adsorption sites for water molecules are the same as for La-bastnäsite. In agreement with water adsorption calorimetry, at low coverage water molecules are strongly stabilized via coordination to the surface Ce3+ ions, whereas at higher coverage they are adsorbed less strongly via hydrogen bonding interaction with the surface anions. Due to similar water adsorption energies on bastnäsite [101[combining macron]1] and calcite [101[combining macron]4] surfaces, the design of collector molecules that selectively bind to

  1. Study of the stability of 5,10,15,20-tetraphenylporphine (TPP) and metalloporphyrins NiTPP, CoTPP, CuTPP, and ZnTPP by differential scanning calorimetry and thermogravimetry

    Energy Technology Data Exchange (ETDEWEB)

    Gamboa, Minerva; Campos, Myriam [Centro de Investigacion y de Estudios Avanzados del IPN, Departamento de Quimica, Av. IPN 2508, 07360, Mexico D.F. (Mexico); Torres, Luis Alfonso, E-mail: ltorres@cinvestav.m [Centro de Investigacion y de Estudios Avanzados del IPN, Departamento de Quimica, Av. IPN 2508, 07360, Mexico D.F. (Mexico)

    2010-05-15

    In this work, the stability of 5,10,15,20-tetraphenylporphine (TPP) and its metallic derivatives, NiTPP, CoTPP, CuTPP, and ZnTPP has been studied through differential scanning calorimetry and thermogravimetry. The decomposition temperatures are (712, 710, 708, 702, and 671) K for NiTPP, CoTPP, CuTPP, ZnTPP, and TPP, respectively. These values are in correspondence with the N-M bond length d{sub M-N}, of the metalloporphyrins. The corresponding molar enthalpies of melting DELTA{sub fus}H{sub m}, were determined as (58, 57, 55, 52, and 44) kJ . mol{sup -1} for the same series. These values are discussed in terms of the crystallographic features in the solid state.

  2. Compatibilidad química por calorimetría diferencial de barrido y termogravimetría del auranofin tabletas 3 mg Chemical compatibility of 3 mg Auranofin tablets demonstrated by differential scanning calorimetry and thermogravimetry

    Directory of Open Access Journals (Sweden)

    Luis Octavio Martínez Álvarez

    2011-03-01

    Full Text Available Como parte de la pre-estabilidad de la preformulación de auranofin tabletas, se realizó un estudio de compatibilidad química, para lo cual se emplearon técnicas de análisis térmico como la calorimetría diferencial de barrido y la termogravimetría. Previo a dichos estudios se caracterizó térmicamente por calorimetría diferencial de barrido el principio activo y cada uno de los excipientes. Posteriormente se procedió a la realización del estudio de compatibilidad química, mediante la preparación de mezclas físicas binarias entre el principio activo y cada uno de los excipientes. Se detectó por ambos métodos que el principio activo tuvo una transición física de fusión, no reportada en la literatura, lo que permitió poder calcular su pureza por calorimetría diferencial de barrido. Mediante la técnica calorimétrica fue posible inferir la ausencia de incompatibilidad química entre el principio activo y los excipientes estudiados. Además, mediante el cálculo de la energía de activación se estableció el siguiente orden de estabilidad térmica: auranofin:PVP> auranofin:lactosa> auranofin:explotab> auranofin:estearato> auranofin:aerosil> auranofin:celulosa, por lo que se recomienda el uso de estos excipientes en la elaboración de la formulación farmacéutica.As part of the pre-stability study of the Auranofin tablet pre-formulation, a chemical compatibility study was conducted using thermal analysis techniques such as the differential scanning calorimetry and the thermogravimetry. Prior to these studies, the active principle and each of the excipients were thermally characterized with the aid of the differential scanning calorimetry. Then, there proceeded to carry out the chemical compatibility study by preparing binary physical mixtures between the active principle and each of the excipients. Both methods showed that the active principle had a melting physical transition, not reported in the literature, which allowed

  3. In vitro model of infected stratum corneum for the efficacy evaluation of poloxamer 407-based formulations of ciclopirox olamine against Trichophyton rubrum as well as differential scanning calorimetry and stability studies.

    Science.gov (United States)

    Täuber, Anja; Müller-Goymann, Christel C

    2015-10-15

    Superficial fungal skin infections are a common disease and concern 20-25% of the world's population with the dermatophyte Trichophyton rubrum being the main trigger. Due to autoinoculation, fungal skin infections of the feet (tinea pedis) often occur simultaneously with fungal nail infections (onychomycosis). Therefore, the overall objective was the development and characterisation of poloxamer 407-based formulations with the antimycotic active ingredient ciclopirox olamine (CPX) for simultaneous antifungal therapy. The formulations consisted of poloxamer 407, water, isopropyl alcohol, propylene glycol and medium chain triglycerides in given ratios. The in vitro antifungal efficacy against T. rubrum was tested in a novel in vitro model of infected stratum corneum in comparison to a marketed semi-solid formulation containing 1% (w/w) ciclopirox olamine and a marketed nail lacquer containing 8% ciclopirox. Several liquid poloxamer 407-based formulations with only 1% CPX completely inhibited fungal growth after 6 days of incubation, whereas the marketed semi-solid formulation did not inhibit fungal growth. Differential scanning calorimetry studies revealing the interaction between the formulations and the SC showed that increasing isopropyl alcohol/propylene glycol concentrations as well as increasing CPX concentrations caused increasing endothermic transition shifts. Moreover, stability studies at 30 °C exhibited only a slight decrease of the CPX amount after 12 months of storage. Each formulation contained >90% of the initial CPX concentration after termination of the stability studies. Copyright © 2015 Elsevier B.V. All rights reserved.

  4. Non-isothermal crystallization kinetics and glass-forming ability of Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} bulk metallic glass investigated by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Pan; Zhao, Shaofan; Yao, Kefu [Tsinghua University, School of Materials Science and Engineering, Beijing (China); Wang, Xin [Hebei University of Technology, School of Materials Science and Engineering, Tianjin (China)

    2015-07-15

    The non-isothermal crystallization kinetics and glass-forming ability of Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} glassy alloy were investigated by differential scanning calorimetry. The activation energies corresponding to the characteristic temperatures have been calculated by Kissinger and Ozawa equations. Based on Kissinger-Akahira-Sunose and Ozawa-Flynn-Wall models, it has been found that the local activation energy is higher at the beginning of the crystallization process for the first exothermic peak. The local Avrami exponent indicates that the first-step crystallization is mainly a high-dimensional nucleation and growth with an increasing nucleation rate. According to the calculated fragility index, Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} alloy can be classified as ''strong glass former.'' The studied alloy also possesses a critical size up to centimeter order, and the high glass-forming ability is probably related to the relatively low Gibbs energy difference between the liquid and crystalline states. The critical cooling rate of Ti{sub 41}Zr{sub 25}Be{sub 28}Fe{sub 6} glassy alloy has also been determined using Barandiaran-Colmenero's method. (orig.)

  5. Indirect calorimetry can be used to measure cardiac output in septic patients? A calorimetria indireta pode ser utilizada para medir o débito cardíaco em pacientes sépticos?

    Directory of Open Access Journals (Sweden)

    Maria Auxiliadora Martins

    2008-01-01

    Full Text Available PURPOSE: The aim of this study was to compare two different cardiac output (CO monitoring systems based on the thermodilution principle (Thermo-CO and indirect calorimetry (Fick mixed-CO in septic patients. METHODS: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Nineteen patients aged on average 45.4 ± 21.5 years were enrolled in the study. Four series of hourly measurements by the two techniques were carried out simultaneously. RESULTS: No significant differences were observed between Thermo-CO and Fick mixed-CO (7.0 ± 1.8 L.min-1 and 6.4 ± 1.7 L.min-1.. Parallel analysis of Fick mixed-CO and Fick atrial-CO was performed introducing a correction factor for the eight atrial samples in order to adjust the values of oxygen saturation obtained from atrial blood (Fick corrected atrial-CO to those obtained from mixed venous blood. No significant differences could be detected between Fick mixed-CO and Fick corrected atrial-CO. The correlation coefficients of Thermo CO/Fick mixed-CO and Fick mixed-CO/Fick corrected atrial-CO were 0.84 and 0.94, respectively. CONCLUSION: We observed that the agreement between the two methods was satisfactory on the basis of the decisions made for treatment. Indirect calorimetry is useful to measure CO in patients with septic shock.OBJETIVO: O objetivo deste estudo foi comparar as medidas do débito cardíaco (DC obtidas pela termodiluição (DC-termo e pela calorimetria indireta (DC-Fick misto em pacientes com choque séptico. MÉTODOS: Estudo prospectivo em pacientes sépticos internados em unidade de terapia intensiva de um hospital universitário. Foram estudados 19 pacientes (45,4 ± 21,5 anos. Foram realizadas quatro séries de medidas do DC pelos dois métodos, simultaneamente. RESULTADOS: Não houve diferenças significativas entre os valores do DC-termo e DC-Fick misto (7,0 ± 1,8 L.min-1 e 6,4 ± 1,7 L.min-1, respectivamente. Na avaliação dos oito casos

  6. An investigation of the hydrogen desorption from Nd{sub 2}Fe{sub 17}H{sub x} and Dy{sub 2}Fe{sub 17}H{sub x} compounds by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Cuevas, F. [ICMPE/CNRS-UPEC, UMR 7182, 2-8, rue Henri Dunant 94320, Thiais (France); Isnard, O., E-mail: olivier.isnard@grenoble.cnrs.fr [Institut Néel du CNRS et Université Joseph Fourier, BP 166 X, 38042 Grenoble cedex 9 (France); Villeroy, B. [ICMPE/CNRS-UPEC, UMR 7182, 2-8, rue Henri Dunant 94320, Thiais (France)

    2013-06-10

    Highlights: • We investigate the hydrogen desorption from R{sub 2}Fe{sub 17}H{sub x} (R = Nd and Dy) compounds. • The heat of hydrogen desorption is 29.2 ± 0.8 kJ mol H{sup −1} for both R{sub 2}Fe{sub 17}H{sub x} family compounds. • Hydrogen desorption activation energies have been determined from DSC. • Thermodynamical data are analysed for both heavy (Dy) and light (Nd) rare earth elements in the light of the precise knowledge of the crystal structure. - Abstract: Hydrogen desorption from R{sub 2}Fe{sub 17}H{sub x} (R = Nd and Dy) compounds with x ≤ 5 has been studied using differential scanning calorimetry (DSC). Overall hydrogen binding energies are very similar in both systems regardless their different crystal structures. The heat of hydrogen desorption is 29.2 ± 0.8 kJ mol H{sup −1} for both R{sub 2}Fe{sub 17}H{sub x} family compounds. Desorption activation energies are also very close: 78 ± 8 kJ and 79 ± 4 kJ mol H{sup −1} for Nd and Dy-containing compounds, respectively. The rare earth nature modifies however the local interaction between hydrogen and the intermetallic compound. For Nd, H-atoms occupy two non-equivalent and well-defined energy sites whereas a unique energy site with a broad energy distribution is detected for Dy. This peculiar behavior is discussed in terms of the different structural properties of the light (Nd) and heavy (Dy) rare-earth R{sub 2}Fe{sub 17} compounds.

  7. Differential scanning calorimetry analysis of an enhanced LiNi{sub 0.8}Co{sub 0.2}O{sub 2} cathode with single wall carbon nanotube conductive additives

    Energy Technology Data Exchange (ETDEWEB)

    Ganter, Matthew J., E-mail: mjg9074@rit.edu [Golisano Institute for Sustainability, Rochester Institute of Technology, 111 Lomb Memorial Drive, Rochester, NY 14623 (United States); DiLeo, Roberta A., E-mail: rad0468@rit.edu [Microsystems Engineering, Rochester Institute of Technology, 111 Lomb Memorial Drive, Rochester, NY 14623 (United States); Schauerman, Christopher M., E-mail: cms3176@rit.edu [Golisano Institute for Sustainability, Rochester Institute of Technology, 111 Lomb Memorial Drive, Rochester, NY 14623 (United States); Rogers, Reginald E., E-mail: rerche@rit.edu [Chemical and Biomedical Engineering, Rochester Institute of Technology, 111 Lomb Memorial Drive, Rochester, NY 14623 (United States); Raffaelle, Ryne P., E-mail: ryne.raffaelle@nrel.gov [National Renewable Energy Laboratory, Golden Colorado, CO 84041 (United States); Landi, Brian J., E-mail: bjlsps@rit.edu [Chemical and Biomedical Engineering, Rochester Institute of Technology, 111 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2011-08-30

    Highlights: {center_dot} Replaced 4 wt% carbon black conductive additives with 1 wt% single wall carbon nanotubes (SWCNTs) in cathode composite. {center_dot} Use of SWCNT additive increased conductivity of cathode composite by over an order of magnitude. {center_dot} SWCNT additive composite had triple the capacity at a 10C rate. {center_dot} SWCNT additive composite reduced exothermic energy released upon delithiation by 40%. - Abstract: The replacement of traditional conductive carbon additives with single wall carbon nanotubes (SWCNTs) in lithium metal oxide cathode composites has been shown to enhance thermal stability as well as power capability and electrode energy density. The dispersion of 1 wt% high purity laser-produced SWCNTs in a LiNi{sub 0.8}Co{sub 0.2}O{sub 2} electrode created an improved percolation network over an equivalent composite electrode using 4 wt% Super C65 carbon black; evidenced by additive connectivity in SEM images and an order of magnitude increase in electrode electrical conductivity. The cathode with 1 wt% SWCNT additives showed comparable active material capacity (185-188 mAh g{sup -1}), at a low rate, and Coulombic efficiency to the cathode composite with 4 wt% Super C65. At increased cycling rates, the cathode with SWCNT additives had higher capacity retention with more than three times the capacity at 10C (16.4 mA cm{sup -2}). The thermal stability of the electrodes was evaluated by differential scanning calorimetry after charging to 4.3 V and float charging for 12 h. A 40% reduction of the cathode exothermic energy released was measured when using 1 wt% SWCNTs as the additive. Thus, the results demonstrate that replacing traditional conductive carbon additives with a lower weight loading of SWCNTs is a simple way to improve the thermal transport, safety, power, and energy characteristics of cathode composites for lithium ion batteries.

  8. Energy expenditure evaluation in humans and non-human primates by SenseWear Armband. Validation of energy expenditure evaluation by SenseWear Armband by direct comparison with indirect calorimetry.

    Directory of Open Access Journals (Sweden)

    Francesca Casiraghi

    Full Text Available INTRODUCTION: The purpose of this study was to compare and validate the use of SenseWear Armband (SWA placed on the arm (SWA ARM and on the back (SWA BACK in healthy humans during resting and a cycle-ergometer exercise and to evaluate the SWA to estimate Resting Energy Expenditure (REE and Total Energy Expenditure (TEE in healthy baboons. METHODS: We studied 26 (15F/11M human subjects wearing SWA in two different anatomical sites (arm and back during resting and a cycle-ergometer test and directly compared these results with indirect calorimetry evaluation (IC, performed at the same time. We then inserted the SWA in a metabolic jacket for baboons and evaluated the TEE and REE in free living condition for 6 days in 21 (8F/13M non-human primates. RESULTS: In humans we found a good correlation between SWA place on the ARM and on the BACK with IC during the resting experiment (1.1±0.3 SWAs, 1±0.2 IC kcal/min and a slight underestimation in the SWAs data compared with IC during the cycle-ergometer exercise (5±1.9 SWA ARM, 4.5±1.5 SWA BACK and 5.4±2.1 IC kcal/min. In the non-human primate (baboons experiment SWA estimated a TEE of 0.54±0.009 kcal/min during free living and a REE of 0.82±0.06 kcal/min. CONCLUSION: SWA, an extremely simple and inexpensive apparatus, provides quite accurate measurements of energy expenditure in humans and in baboons. Energy expenditure data obtained with SWA are highly correlated with the data obtained with "gold standard", IC, in humans.

  9. Non-isothermal crystallization kinetics and fragility of (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} bulk metallic glass investigated by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Man, E-mail: zhuman0428@126.com [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an, Shaanxi 710032 (China); Li, Junjie [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China); Yao, Lijuan; Jian, Zengyun; Chang, Fang’e [School of Materials and Chemical Engineering, Xi’an Technological University, Xi’an, Shaanxi 710032 (China); Yang, Gencang [State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an, Shaanxi 710072 (China)

    2013-08-10

    Highlights: • Non-isothermal crystallization kinetics of (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} BMGs was studied. • Two-stage of crystallization process is confirmed by DSC. • The nucleation process is difficult than growth process during crystallization. • The second crystallization process is the most sensitive to heating rate. • Kinetic fragility index is evaluated suggesting it is an intermediate glass. - Abstract: In this paper, bulk metallic glasses with the composition of (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} were prepared by copper mold casting technique. X-ray diffraction (XRD) and differential scanning calorimetry (DSC) were used to investigate its structure and non-isothermal crystallization kinetics. DSC traces revealed that it undergoes two-stage crystallization. The activation energies corresponding to the characteristic temperatures have been calculated, and the results reveal that the as-cast alloys have a good thermal stability in thermodynamics. Based on Kissinger equation, the activation energies for glass transition, the first and second crystallization processes were obtained as 485 ± 16 kJ/mol, 331 ± 7 kJ/mol and 210 ± 3 kJ/mol, respectively, suggesting that the nucleation process is more difficult than the grain growth process. The fitting curves using Lasocka's empirical relation show that the influence of the heating rate for crystallization is larger than glass transition. Furthermore, the kinetic fragility for (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} bulk metallic glasses is evaluated. Depending on the fragility index, (Cu{sub 46}Zr{sub 47}Al{sub 7}){sub 97}Ti{sub 3} bulk metallic glasses should be considered as “intermediate glasses”.

  10. Calorimetry at the CMD-3 Detector

    CERN Document Server

    Razuvaev, G P; Anisenkov, A V; Aulchenko, V M; Bashtavoy, N S; Epifanov, D A; Epshteyn, L B; Erofeev, A L; Grebenuk, A A; Grigoriev, D N; Kazanin, V F; Kovalenko, O A; Kozyrev, A N; Kuzmenko, A E; Kuzmin, A S; Logashenko, I B; Mikhailov, K Yu; Okhapkin, V S; Ruban, A A; Shebalin, V E; Shwartz, B A; Talyshev, A A; Titov, V M; Yudin, Yu V

    2017-01-01

    The general purpose detector CMD-3 has been collecting data since 2010 in an energy range 0.32–2 GeV at the e+e- collider VEPP-2000 at the Budeker Institute of Nuclear Physics. The detector physics program includes the study of the e+e- annihilation into hadrons. To supply high registration efficiency for neutral particles the CMD-3 has an electromagnetic calorimeter consisted of three subsystems: BGO endcap calorimeter and barrel one with an inner part based on LXe and outer on CsI crystals. The main parameters of calorimeters, cluster reconstruction and calibration procedures with performance results are described.

  11. Hadron calorimetry in the L3 detector

    Energy Technology Data Exchange (ETDEWEB)

    Adriani, O.; Civinini, C.; D' Alessandro, R.; Gallo, E.; Marchionni, A.; Meschini, M.; Pieri, M.; Wang, Y.F. (Istituto Nazionale di Fisica Nucleare, Florence (Italy) Florence Univ. (Italy)); Arefiev, A.; Galaktionov, Yu.; Gordeev, A.; Gorodkov, Yu.; Kamyshkov, Y.U.; Klimentov, A.; Koutsenko, V.; Malinin, A.; Morgunov, V.; Plyaskin, V.; Pojidaev, V.; Savin, A.; Shevchenko, S.; Shevchenko, V.; Shmakov, K.; Shoumilov, E.; Shoutko, V.; Tarkovsky, E.; Vetlitsky, I.; Vorobiev, I. (Institut Teoreticheskoj i Ehksperimental' noj Fiziki, Moscow (USSR)); An, Q.; Blomeke, P.; Cai, X.; Cui, X.; Gong, Z.F.; Ilyas, M.M.; Khan, R.; Kumar, V.; Kunin, A.; Lin, Y.B.; Qureshi, K.; Siedling, R.; Wadhawa, M.; Wu, R.J.; Wu, S.W.; Wu, Y.G.; Zichichi, A. (World Lab., Geneva (Switzerland). FBLJA Project); Azemoon, T.; Ball, R.C.; Capell, M.; Chen, M.L.; Goldfarb, S.; Jones, L.W.; Mills, G.B.; Roe, B.P. (Michigan Univ., Ann Arbor (USA)); Aziz, T.; Banerjee, S.; Chendvankar, S.R.; Ganguli, S.N.; Gurtu, A.; Malh

    1991-04-01

    The characteristics of the L3 hadron calorimeter as realized in the observation of hadronic jets and other events from e{sup +}e{sup -} c collisions at LEP are presented and discussed. The pattern-recognition algorithm utilizing the fine granularity of the calorimeter is described, and the observed overall resolution of 10.2% for hadron jets from Z decay is reported. The use of the calorimeter in providing information on muon energy losses is also noted. (orig.).

  12. Indirect Calorimetry in Mechanically Ventilated Patients

    DEFF Research Database (Denmark)

    Allingstrup, Matilde Jo; Kondrup, Jens; Perner, Anders

    2017-01-01

    Background and Aims: The 2 currently available indirect calorimeters, CCM Express Indirect Calorimeter (MedGraphics, St Paul, MN) and Quark RMR ICU Indirect Calorimeter (COSMED, Rome, Italy), have not been validated against a gold standard in mechanically ventilated patients. Our aim was to do so...

  13. Calorimetry at the International Linear Collider

    Energy Technology Data Exchange (ETDEWEB)

    Repond, Jose [Argonne National Laboratory, Argonne, IL (United States)]. E-mail: respond@hep.anl.gov

    2007-03-01

    The physics potential of the International Linear Collider depends critically on the jet energy resolution of its detector. Detector concepts are being developed which optimize the jet energy resolution, with the aim of achieving {sigma}{sub jet}=30%/E{sub jet}. Under the assumption that Particle Flow Algorithms (PFAs), which combine tracking and calorimeter information to reconstruct the energy of hadronic jets, can provide this unprecedented jet energy resolution, calorimeters with very fine granularity are being developed. After a brief introduction outlining the principles of PFAs, the current status of various calorimeter prototype construction projects and their plans for the next few years will be reviewed.

  14. New ideas and developments in calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Gordon, H.A.

    1981-01-01

    The challenges for calorimeter performance in the next decade are reviewed. Some new ideas for calorimeters are described: (1) the test of a parallel plate calorimeter; (2) the use of vacuum photodiodes for calorimeters operating in a magnetic field; (3) the attempt to build high pressure gas sealed tubes as ion chambers in hadron calorimeters; (4) the progress in the attempt to mold plastic loaded with heavy metal for the inert material in gas calorimeters; and (5) the use of the limited streamer mode in calorimeters.

  15. Performance of Particle Flow Calorimetry at CLIC

    CERN Document Server

    Marshall, J.S.; Thomson, M.A.

    2013-01-01

    The experimental conditions at CLIC are also significantly more challenging than those at previous electron-positron colliders, with increased levels of beam-induced backgrounds combined with a bunch spacing of only 0.5 ns. This paper describes the modifications made to the PandoraPFA particle flow algorithm to improve the jet energy reconstruction for jet energies above 250 GeV. It then introduces a combination of timing and pT cuts that can be applied to reconstructed particles in order to significantly reduce the background. A systematic study is...

  16. A simplistic view of hadron calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Groom, Donald E.

    2006-11-16

    All too often we rely on Monte Carlo simulations withoutworrying too much about basic physics. It is possible to start with avery simple calorimeter (a big cylinder) and learn the functional form ofpi e by aninduction argument. Monte Carlo simulations provide sanitychecks and constants. A power-law functional form describes test beamresults surprisingly well. The prediction that calorimeters responddifferently to protons and pions of the same energy was unexpected. Theeffect was later demonstrated by the CMS forward calorimeter group, usingthe most noncompensating calorimeter ever built. Calorimeter resolutionis dominated by fluctuations in piz production and the energy deposit byneutrons. The DREAM collaboration has recently used a dual readoutcalorimeter to eliminate the first of these. Ultimate resolution dependson measuring neutrons on an event-by-event basis as well.

  17. Calorimetry of the CMD-3 detector

    Science.gov (United States)

    Akhmetshin, R. R.; Anisenkov, A. V.; Aulchenko, V. M.; Bashtovoy, N. S.; Epifanov, D. A.; Epshteyn, L. B.; Erofeev, A. L.; Grebenuk, A. A.; Grigoriev, D. N.; Kazanin, V. F.; Kovalenko, O. A.; Kozyrev, A. N.; Kuzmenko, A. E.; Kuzmin, A. S.; Logashenko, I. B.; Mikhailov, K. Yu; Okhapkin, V. S.; Razuvaev, G. P.; Ruban, A. A.; Shebalin, V. E.; Shwartz, B. A.; Titov, V. M.; Talyshev, A. A.; Yudin, Yu V.

    2017-11-01

    The CMD-3 detector has been collecting data since 2010 at the e + e ‑ collider VEPP-2000 in the Budker Institute of Nuclear Physics. VEPP-2000 uses the novel round beam technique and provides high luminosity in a wide c.m.energy range from 0.32 to 2 GeV. The physics goal of the CMD-3 experiment is a study of the e + e ‑ annihilation into hadrons. CMD-3 is a general-purpose detector, which provides high efficiency for both charged and neutral particles. The electromagnetic calorimeter consists of the barrel calorimeter based on liquid xenon and CsI crystals, and the endcap calorimeter based on BGO crystals. The main parameters of the calorimeters are presented.

  18. Calorimetry at the International Linear Collider

    Science.gov (United States)

    Repond, José

    2007-03-01

    The physics potential of the International Linear Collider depends critically on the jet energy resolution of its detector. Detector concepts are being developed which optimize the jet energy resolution, with the aim of achieving σjet=30%/√{Ejet}. Under the assumption that Particle Flow Algorithms (PFAs), which combine tracking and calorimeter information to reconstruct the energy of hadronic jets, can provide this unprecedented jet energy resolution, calorimeters with very fine granularity are being developed. After a brief introduction outlining the principles of PFAs, the current status of various calorimeter prototype construction projects and their plans for the next few years will be reviewed.

  19. ATLAS calorimetry. Trigger, simulation and jet calibration

    Energy Technology Data Exchange (ETDEWEB)

    Weber, P.

    2007-02-06

    The Pre-Processor system of the ATLAS Level-1 Calorimeter Trigger performs complex processing of analog trigger tower signals from electromagnetic and hadronic calorimeters. The main processing block of the Pre-Processor System is the Multi-Chip Module (MCM). The first part of this thesis describes MCM quality assurance tests that have been developed, their use in the MCM large scale production and the results that have been obtained. In the second part of the thesis a validation of a shower parametrisation model for the ATLAS fast simulation package ATLFAST based on QCD dijet events is performed. A detailed comparison of jet response and jet energy resolution between the fast and the full simulation is presented. The uniformity of the calorimeter response has a significant impact on the accuracy of the jet energy measurement. A study of the calorimeter intercalibration using QCD dijet events is presented in the last part of the thesis. The intercalibration study is performed in azimuth angle {phi} and in pseudorapidity {eta}. The performance of the calibration methods including possible systematic and statistical effects is described. (orig.)

  20. ATLAS calorimetry: Trigger, simulation and jet calibration

    CERN Document Server

    Weber, Pavel

    2008-01-01

    The Pre-Processor system of the ATLAS Level-1 Calorimeter Trigger performs complex processing of analog trigger tower signals from electromagnetic and hadronic calorimeters. The main processing block of the Pre-Processor System is the Multi-Chip Module (MCM). The first part of this thesis describes MCM quality assurance tests that have been developed, their use in the MCM large scale production and the results that have been obtained. In the second part of the thesis a validation of a shower parametrisation model for the ATLAS fast simulation package ATLFAST based on QCD dijet events is performed. A detailed comparison of jet response and jet energy resolution between the fast and the full simulation is presented. The uniformity of the calorimeter response has a significant impact on the accuracy of the jet energy measurement. A study of the calorimeter intercalibration using QCD dijet events is presented in the last part of the thesis. The intercalibration study is performed in azimuth angle phi and in pseud...

  1. Large lead tungstate crystals for calorimetry

    CERN Document Server

    Lecomte, P

    2000-01-01

    PbWO//4 crystals have been selected for the CMS Experiment at LHC, rather than the higher light yield but bulkier CeF//3, because space is at a premium in the 4T supraconductive magnet. Early PbWO//4 samples exhibited severe low dose radiation damage, slow components or long term afterglow. Thus, major R&D efforts have been undertaken by the Russian and Chinese producers. Besides improving the control of the raw materials, the stoichiometry and the growth parameters, the R&D efforts explored two avenues: doping of the crystals and oxygen annealing. Both groups have produced full size crystals which satisfy the requirements of CMS, including the low production cost which is an overwhelming consideration and a severe constraint in the optimization of the production process. This paper concentrates on the development of Chinese crystals; it attempts to guide the reader through the complex development process by giving a very brief description of the main steps and issues addressed in the past five years,...

  2. Isothermal calorimetry of enzymatic biodiesel reaction

    DEFF Research Database (Denmark)

    Fjerbæk Søtoft, Lene; Westh, Peter; Christensen, Knud Villy

    2010-01-01

    reaction mixture kinetics using ITC. It is possible to determine thermodynamic properties like reaction enthalpy and reaction rate, and the difficulty in actually measuring the true non-mass transfer limited reaction kinetics is exposed by the high time resolution of ITC. Based on the measured enthalpy...... and composition change in the system, the heat of reaction at 40°C for the two systems has been determined to -9.8 ± 0.9 kJ/mole biodiesel formed from rapeseed oil and methanol, and - 9.3 ± 0.7 kJ/mole when rapeseed oil and ethanol is used....

  3. The Use of Differential Scanning Calorimetry in Studies of Wax Deposition: Measuring the Solid Formation and Binary Solid-Liquid Equilibrium Phase Diagrams La DSC (Differential Scanning Calorimetry appliquée à l'étude des dépôts de paraffines : mesure des quantités de dépôts et des diagrammes de phases (liquide-solide de mélange binaire

    Directory of Open Access Journals (Sweden)

    Coutinho J. A. P.

    2006-12-01

    Full Text Available The studies of wax formation in hydrocarbon mixtures, both crudes and refined products such as diesels and fuels, require measuring techniques able to deal with the solid phase behaviour. Experimental data on phase equilibria is important to understand the crystallisation of paraffins and for the development of thermodynamical models, that can describe it. It is here shown how the information obtained from Differential Scanning Calorimetry (DSC measurements can be used to assess the amount of solid forming when a fluid is cooled and also to make faster measurements of phase diagrams for binary systems where no solid solutions exist. The measurements performed with the proposed methods present a good agreement with literature data. L'étude de la cristallisation des paraffines dans les mélanges hydrocarbonés, qu'il s'agisse de pétroles bruts ou de produits raffinés tels que le Diesel ou le fioul, nécessite l'utilisation de techniques expérimentales permettant de déterminer le diagramme de phases. L'acquisition de ces données est primordiale, à la fois pour comprendre les mécanismes de la cristallisation et pour le développement des modèles thermodynamiques. Dans cet article, nous montrons comment l'analyse calorimétrique différentielle peut permettre d'estimer la quantité de solide déposée en fonction de la température et de mesurer les diagrammes de phases de mélanges binaires ne formant pas de solutions solides. Les résultats obtenus avec la méthode proposée s'accordent avec les données de la littérature.

  4. Estudo termoanalítico de comprimidos revestidos contendo captopril através de termogravimetria (TG e calorimetria exploratória diferencial (DSC Thermal analysis study of captopril coated tablets by thermogravimetry (TG and differential scanning calorimetry (DSC

    Directory of Open Access Journals (Sweden)

    Giovana Carolina Bazzo

    2005-09-01

    Full Text Available No presente trabalho foram desenvolvidos comprimidos de captopril revestidos com hidroxipropilmetilcelulose (HPMC, Opadry®, polivinilpirrolidona (PVP, Eudragit® E e goma laca. Foi realizado estudo termoanalítico do fármaco e das formulações através de termogravimetria (TG e calorimetria exploratória diferencial (DSC. Através da análise das curvas DSC verificou-se que não houve a ocorrência de interação entre o fármaco e os excipientes lactose, celulose microcristalina, croscarmelose sódica, Aerosil® e talco, utilizados na formulação do comprimido. Através desta técnica detectou-se a possibilidade de interação entre captopril e estearato de magnésio. De acordo com os resultados obtidos através de DSC não foram observadas alterações na cristalinidade do fármaco decorrentes dos processos de compressão e revestimento. A termogravimetria foi utilizada para o estudo da cinética de degradação do captopril e dos comprimidos. Os parâmetros cinéticos foram determinados através do método de Ozawa. Os resultados demonstraram que não houve alteração da estabilidade térmica do captopril na forma de comprimido. A formulação revestida com HPMC foi a que apresentou maior estabilidade térmica, quando comparada às demais formulações de revestimento.In the present study, captopril coated tablets with hydroxypropylmethylcellulose (HPMC, Opadry®, polyvinylpirrolidone (PVP, Eudragit® and shellac were produced. Differential scanning calorimetry (DSC and thermogravimetry (TG were used to evaluate the thermal properties of the drug and the formulations. On the basis of DSC results, captopril was found to be compatible with lactose, microcrystalline cellulose, sodium croscarmellose, Aerosil® and talc. Some possibility of interaction between drug-excipient was observed with magnesium stearate. However, additional techniques to confirm the results obtained are needed. There was no influence of mechanical treatment (tableting

  5. A comprehensive physicochemical, thermal, and spectroscopic characterization of zinc (II) chloride using X-ray diffraction, particle size distribution, differential scanning calorimetry, thermogravimetric analysis/differential thermogravimetric analysis, ultraviolet-visible, and Fourier transform-infrared spectroscopy.

    Science.gov (United States)

    Trivedi, Mahendra Kumar; Sethi, Kalyan Kumar; Panda, Parthasarathi; Jana, Snehasis

    2017-01-01

    Zinc chloride is an important inorganic compound used as a source of zinc and has other numerous industrial applications. Unfortunately, it lacks reliable and accurate physicochemical, thermal, and spectral characterization information altogether. Hence, the authors tried to explore in-depth characterization of zinc chloride using the modern analytical technique. The analysis of zinc chloride was performed using powder X-ray diffraction (PXRD), particle size distribution, differential scanning calorimetry (DSC), thermogravimetric analysis/differential thermogravimetric analysis (TGA/DTG), ultraviolet-visible spectroscopy (UV-vis), and Fourier transform-infrared (FT-IR) analytical techniques. The PXRD patterns showed well-defined, narrow, sharp, and the significant peaks. The crystallite size was found in the range of 14.70-55.40 nm and showed average crystallite size of 41.34 nm. The average particle size was found to be of 1.123 (d10), 3.025 (d50), and 6.712 (d90) μm and average surface area of 2.71 m2/g. The span and relative span values were 5.849 μm and 1.93, respectively. The DSC thermogram showed a small endothermic inflation at 308.10°C with the latent heat (ΔH) of fusion 28.52 J/g. An exothermic reaction was observed at 449.32°C with the ΔH of decomposition 66.10 J/g. The TGA revealed two steps of the thermal degradation and lost 8.207 and 89.72% of weight in the first and second step of degradation, respectively. Similarly, the DTG analysis disclosed Tmax at 508.21°C. The UV-vis spectrum showed absorbance maxima at 197.60 nm (λmax), and FT-IR spectrum showed a peak at 511/cm might be due to the Zn-Cl stretching. These in-depth, comprehensive data would be very much useful in all stages of nutraceuticals/pharmaceuticals formulation research and development and other industrial applications.

  6. Validation of physical activity monitors in individuals with diabetes: energy expenditure estimation by the multisensor SenseWear Armband Pro3 and the step counter Omron HJ-720 against indirect calorimetry during walking.

    Science.gov (United States)

    Machač, Stanislav; Procházka, Michal; Radvanský, Jiří; Slabý, Kryštof

    2013-05-01

    The purpose of this study is to test the agreement between energy expenditure estimate of the SenseWear(®) Armband Pro3 (SWA) (BodyMedia, Pittsburgh, PA) and the Omron HJ-720 (Omron Healthcare, Kyoto, Japan) step counter with indirect calorimetry (IC) as a gold standard in older individuals with type 1 and type 2 diabetes mellitus while walking on a treadmill. In total, six men (60.3±3.1 years old) and 13 women (51.1±11.0 years old) with type 1 or type 2 diabetes mellitus were included in the study. Each subject performed three 15-min walking sessions with different combinations of speed and incline (3 km/h, 0%; 4 km/h, 0%; 5 km/h, 5%) on a treadmill. Energy expenditure (EE) was simultaneously measured by the SWA, Omron, and IC. Mean over-/underestimation and Pearson's correlation coefficients were used for statistical evaluation of the agreement between tested methods and IC. At the speed of 3 km/h with 0% incline, mean overestimation of +81.19±23.81% was found for SWA (r=0.79, P<0.001) and +70.51±20.91% for Omron (r=0.77, P<0.001). At the speed of 4 km/h and 0% incline, mean overestimation found for SWA was +78.18±33.96% (r=0.63, P<0.01) and +75.77±33.36% for Omron (r=0.52, P<0.05). At the level of high-intensity exercise at the speed of 5 km/h and 5% incline, mean underestimation was -7.88±16.86% for SWA (r=0.74, P<0.001) and -7.37±16.07% for Omron (r=0.75, P<0.001). Both methods led to considerable overestimation of calculated EE in level walking and a relatively minor underestimation during fast uphill walking.

  7. Gasto energético em adolescentes asmáticos com excesso de peso: calorimetria indireta e equações de predição Energy expenditure in overweight, asthmatic adolescents: indirect calorimetry and prediction equations

    Directory of Open Access Journals (Sweden)

    Franceliane Jobim Benedetti

    2011-02-01

    Full Text Available OBJETIVO: Comparar o gasto energético medido por calorimetria indireta com o estimado por equações de predição entre adolescentes asmáticos e não asmáticos. MÉTODOS: Trata-se de estudo transversal com 69 adolescentes de 10 a 18 anos. Foram comparados três grupos pareados (asmáticos com excesso de peso, asmáticos eutróficos e não asmáticos com excesso de peso. Para avaliação nutricional utilizaram-se medidas antropométricas e de composição corporal. O gasto energético foi medido por calorimetria indireta e estimado por fórmulas de predição. RESULTADOS: Cada grupo foi composto por 23 adolescentes, dos quais 10 do sexo feminino, com média de idade de M=12,4, DP=2,4 anos. O gasto energético de repouso, pela calorimetria indireta nos asmáticos com excesso de peso, foi de M=1550,2, DP=547,2kcal/dia; nos asmáticos eutróficos, M=1540,8, DP=544,2kcal/dia; e nos não asmáticos com excesso de peso, M=1697,2, DP=379,8kcal/dia, com resultado semelhante entre os grupos, mesmo quando ajustado pela massa magra e massa gorda (f=0,186; p=0,831. Obtiveram-se achados semelhantes entre o gasto energético medido pela calorimetria indireta e o estimado pelas fórmulas de predição, com exceção da fórmula de Harris-Benedict, que subestimou o gasto energético nos asmáticos eutróficos e nos não asmáticos com excesso de peso. CONCLUSÃO: O gasto energético de repouso não foi estatisticamente diferente entre os grupos asmáticos e não asmáticos, mesmo quando ajustado pela massa magra e massa gorda. Para os três grupos, as equações de predição são úteis para estimar o gasto energético de repouso e o gasto energético total.OBJECTIVE: This study compared the energy expenditure measured by indirect calorimetry with that estimated by prediction equations in asthmatic and non-asthmatic adolescents. METHODS: This was a cross-sectional study with 69 adolescents aged 10 to 18 years. Three paired groups were compared (overweight

  8. Aplicação da calorimetria exploratória diferencial no estudo da cinética de transição alfa -> delta HMX Application of differential scanning calorimetry in the study of the kinetics of the alpha -> delta transition in HMX

    Directory of Open Access Journals (Sweden)

    Gilson da Silva

    2004-12-01

    Full Text Available Octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine (HMX or octogen is a white crystalline substance which occurs in four polymorphous forms. It is used in a wide variety of military and industrial formulations owing to its suitable properties. Researchers have demonstrated the usefulness of this energetic material in explosive components. In the present work we apply differential scanning calorimetry (DSC to measure the a ® d solid-solid phase transition energy of HMX. The results obtained by Kissinger's and Ozawa's methods were 487 and 495 kJ/mol, respectively.

  9. Net energy of hemp hulls and processed hemp hull products fed to growing pigs and the comparison of net energy determined via indirect calorimetry and calculated from prediction equations.

    Science.gov (United States)

    Kim, J W; Nyachoti, C M

    2017-06-01

    An experiment was conducted to determine the NE of hemp hulls (HH), extruded HH (EHH), and a blended product of HH with pea (HHP) fed to growing pigs using indirect calorimetry (IC) and to determine effects of dietary fiber on heat production (HP) and fasting HP (FHP). Twenty-four growing barrows with an average initial BW of 22.9 ± 1.75 kg were individually housed in adjustable metabolism crates. Pigs were randomly allotted to 1 of 4 dietary treatments with 6 replicates per treatment. A corn-soybean meal basal diet was prepared. Three additional diets were formulated to contain a constant ratio of corn and soybean meal and each of the test ingredients. Pigs were fed experimental diets for 16 d including 10 d for adaptation and 6 d for total collection of feces and urine to determine DE and ME of experimental diets. Pigs were then moved into IC chambers to determine HP and FHP. The apparent total tract digestibility (ATTD) of DM was greater ( < 0.01) in the HHP diet than in the HH and EHH diets but less ( < 0.01) than in the basal diet. Similarly, the ATTD of GE in the basal diet was greater ( < 0.01) compared with the HH, EHH, and HHP diets. The DE, ME, and NE of the basal diet were greater ( < 0.01) than those of the HH, EHH, and HHP diets. No significant differences were observed for the HP (on average, 1,904 kcal/kg DM) and FHP (on average, 1,320 kcal/kg DM) among treatments. However, the retained energy of pigs fed the basal diet (1,763 kcal/kg DM) was greater ( < 0.05) than for those fed the HH (1,501 kcal/kg DM) and HHP (1,482 kcal/kg DM) diets. The NE:ME ratio tended to be greater ( ≤ 0.10) for the basal diet (0.85) than for the HH (0.82), EHH (0.82), and HHP (0.83) diets. The NE of HH, EHH, and HHP determined by the IC method were 2,375, 2,320, and 2,399 kcal/kg DM, respectively, whereas values calculated using published prediction equations were 2,308, 2,161, and 2,278 kcal/kg DM, respectively. However there was no difference between determined and

  10. Taxa metabólica de repouso de ciclistas estimada por equações e obtida por calorimetria indireta Resting metabolic rate of cyclists estimated by mathematical equations and obtained by indirect calorimetry

    Directory of Open Access Journals (Sweden)

    Paula Guedes Cocate

    2009-10-01

    Full Text Available A taxa metabólica de repouso (TMR pode ser determinada por calorimetria indireta (CI. Porém, em função da praticidade, na prática clínica na maioria das vezes esta é estimada por equações de predição, as quais foram desenvolvidas em estudos envolvendo indivíduos não atletas. Apesar de alguns autores terem indicado que tais equações não estimam adequadamente a TMR, estas têm sido bastante utilizadas para calculá-la e prescrever dietas, inclusive para atletas. O objetivo deste estudo foi comparar a TMR determinada por CI com a estimada pelas equações de Harris & Benedict (HB, Schofield, FAO/WHO/UNU e Henry & Rees (HR, em 15 homens ciclistas, de 24,4 ± 3,68 anos, apresentando índice de massa corporal de 21,97 ± 1,46kg/m² e VO2máx de 70,00 ± 5,32mL(kg.min-1. Para comparar a TMR determinada por CI e pelas equações, utilizou-se o tratamento estatístico testes t de Student (variáveis com distribuição normal e de Mann-Whitney (variáveis sem distribuição normal, considerando p The resting metabolic rate (RMR can be determined by indirect calorimetry (IC. However, the clinical estimation of this parameter has been done using mathematical equations, which were developed in studies involving non-athletes. Although some authors have indicated that such equations do not estimate correctly the RMR, they have been constantly used to estimate such parameter and to prescribe diets, including for athletes. The objective of this study was to compare the RMR determined by IC with the ones estimated using the equations proposed by Harris & Benedict (HB, Schofield, FAO/WHO/UNU and Henry & Rees (HR, in 15 male cyclists, aged 24.4±3.68 years, body mass index of 21.97±1.46 kg/m² and VO2max of 70.00±5.32 mL(kg.min-1. Student's t test (when data presented normal distribution and Mann-Whitney (when data did not present normal distribution were used to compare the RMR determined by IC and the ones estimated by the equations. Probability

  11. Calorimetry Hadronic with semidigital reading based on camera of resistive planes of glass for experiments on collision linear e + e-; Calorimetr@a hadr@nica con lectura semidigital basada en c@mara de planos resistivos de vidrio para experimentos en colisionadores lineales e + e-

    Energy Technology Data Exchange (ETDEWEB)

    Berenguer Antequera, J.

    2015-07-01

    Calorimetry Hadronic with semidigital reading based on camera of resistive planes of glass for experiments on collision linear e + e-. Electron-positron linear colliders have been proposed as next generation particle colliders to complement and extend the physics programme of the LHC (Large Hadron Collider) at CERN. Currently, two projects, ILC (International Linear Collider) and CLIC (Compact LInear Collider), have been suggested by the international community to reach this purpose. The requirements for a detector for both linear colliders are defined by the precision needed to fully exploit the physics potential of these colliders. In particular, one of the most important requirements is an excellent jet energy resolution. This can be achieved with the particle-flow concept in which the overall detector performance for jet reconstruction is optimised by reconstructing each particle individually. For this reason, the calorimeter system has to have unprecedented granularity fulfilling the task of shower separation and providing excellent jet energy resolution and background separation. (Author)

  12. Correlação entre o consumo de oxigênio obtido pelo método de Fick e pela calorimetria indireta no paciente grave Correlation between oxygen consumption calculated using Fick's method and measured with indirect calorimetry in critically ill patients

    Directory of Open Access Journals (Sweden)

    Flávio Marson

    2004-01-01

    Full Text Available OBJETIVO: Correlacionar o índice de consumo de oxigênio medido através da calorimetria indireta (VO2I DELTA às medidas calculadas pela equação reversa de Fick (VO2I FICK em pacientes graves, vítimas de trauma ou sepse. MÉTODOS: Analisados 14 pacientes vítimas de trauma (n=5 ou sepse (n=9, com média de idade de 39,4 ± 5,4 anos, sendo 10 homens e 4 mulheres, APACHE II de 21,3±1,8, ISS de 24,8±6, Sepsis Score de 19,6±2,3, com risco de óbito calculado pelo APACHE II de 41,9±7,1%, submetidos à ventilação mecânica e monitorização hemodinâmica invasiva com cateter de Swan-Ganz e realizadas, pelos dois métodos, 4 séries de medidas do VO2I (T1 a T4. RESULTADOS: Houve uma boa correlação entre os dois métodos (r = 0,77, para a média das quatro medidas seriadas. Não houve diferença estatisticamente significativa entre os dois métodos nos tempos T1 (VO2I DELTA = 138±28 e VO2I FICK = 159±38 mL.min-1.m-2, p = 0,10 e T3 (VO2I DELTA = 144±26 e VO2I FICK = 158±35 mL.min-1.m-2, p = 0,14. Houve diferença significativa nos tempos T2 (VO2I DELTA = 141±27 e VO2I FICK = 155±26 mL.min-1.m-2, p = 0,03 e T4 (VO2I DELTA = 145±24 e VO2I FICK = 162±26 mL.min-1.m-2, p = 0,01. CONCLUSÃO: A calorimetria indireta é um método não invasivo, isento de complicações, que pode ser usado para avaliação do consumo de oxigênio no paciente grave de forma tão eficaz quanto à equação reversa de Fick.OBJECTIVE: To compare the oxygen consumption index measured by using indirect calorimetry (VO2I Delta with a portable metabolic cart and calculated according to Fick's principle (VO2 I Fick in critically ill patients. METHODS: Fourteen patients (10 men and 4 women, mean age 39.4 ± 5.4 years were analyzed, 5 of them trauma victims and 9 sepsis victims. The following mean scores were obtained for these patients: APACHE II = 21.3±1.8, ISS = 24.8±6, and sepsis score = 19.6±2.3. The mortality risk (odds ratio, calculated from APACHE II, was 41

  13. Dual-Readout Calorimetry with Lead Tungstate Crystals

    CERN Document Server

    Akchurin, N; Cardini, A; Ferrari, R; Gaudio, G; Hauptman, J; Kim, H; La Rotonda, L; Livan, M; Meoni, E; Paar, H; Penzo, Aldo L; Pinci, D; Policicchio, Antonio; Popescu, S; Susinno, G; Roh, Y; Vandelli, W; Wigmans, R

    2008-01-01

    Results are presented of beam tests in which a small electromagnetic calorimeter consisting of lead tungstate crystals was exposed to 50 GeV electrons and pions. This calorimeter was backed up by the DREAM Dual-Readout calorimeter, which measures the scintillation and \\v{C}erenkov light produced in the shower development, using two different media. The signals from the crystal calorimeter were analyzed in great detail in an attempt to determine the contributions from these two types of light to the signals, event by event. This information makes it possible to eliminate the dominating source of fluctuations and thus achieve an important improvement in hadronic calorimeter performance.

  14. Dual-Readout Calorimetry for High-Quality Energy

    CERN Multimedia

    During the past seven years, the DREAM collaboration has systematically investigated all factors that determine and limit the precision with which the properties of hadrons and jets can be measured in calorimeters. Using simultaneous detection of the deposited energy and the Cerenkov light produced in hadronic shower development ${(dual}$ ${readout}$), the fluctuations in the electromagnetic shower fraction could be measured event by event their effects on signal linearity, response function and energy resolution eliminated. Detailed measurement of the time structure of the signals made it possible to measure the contirbutions of nuclear evaporation neutrons to the signals and thus reduce the effects of fluctuations in "invisible energy". We are now embarking on the construction of a full-scale calorimeter which incorporates all these elements and which should make it possible to measure the four-vectors of both electrons, hadrons and jets with very high precision, in an instrument that can be simply calibrat...

  15. Shashlik Calorimetry A Combined Shashlik + Preshower Detector for LHC

    CERN Multimedia

    2002-01-01

    % RD36 \\\\ \\\\ New techniques have been developed to read out the light from lead/scintillator sampling calorimeters. These techniques involve the use of wavelength shifting optical fibres. The use of optical fibres enables fine lateral segmentation to be achieved with a minimum of dead space. In addition, it was expected and now confirmed that such calorimeter can be built at a relatively low cost. A good optimized mechanical design was studied for the CMS electromagnetic calorimeter. Several new projective prototypes have been built and tested in electron beams at CERN. The light yields are in excess of 20 photons per MeV. The energy resolution measured on projective towers (42~x~42~mm$^{2}$ at front face) from our last 6~x~6~matrix prototype is: \\\\ \\\\\\[\\frac{\\sigma}{E} = \\frac{.08}{\\sqrt E} \\oplus \\frac{.3}{E} \\oplus~0.005~~~~~(E~~~ in~GeV) \\] \\\\ \\\\The uniformity of the response has also been investigated on an area of 20~x~20~cm$^{2}$. A mean dispersion of less than $\\pm$~1\\% has been achieved. Prototype to...

  16. High-heat-flux sensor calibration using calorimetry

    Science.gov (United States)

    Ballestrín, J.; Estrada, C. A.; Rodríguez-Alonso, M.; Pérez-Rábago, C.; Langley, L. W.; Barnes, A.

    2004-08-01

    This paper demonstrates a calorimetric procedure for calibrating high-heat-flux sensors. The results are in agreement with calibrations obtained using black-body radiation. However, the proposed method has the potential of being more accurate than traditional approaches. This new procedure calibrates sensors to measure correctly under conditions of concentrated solar radiation. At present, the thermal balance calibration technique in the laboratory is limited to solar irradiances of approximately 100 kW m-2. The next step is to demonstrate this methodology to higher irradiances under non-laboratory conditions in the CIEMAT solar furnace at Plataforma Solar de Almería.

  17. Analytical methods for lignin characterization - Differential scanning calorimetry

    NARCIS (Netherlands)

    Koullas, D.P.; Koukios, E.G.; Avgerinos, E.; Abaecherli, A.; Gosselink, R.; Vasile, C.; Lehnen, R.; Saake, B.; Suren, J.

    2006-01-01

    Results of a round robin on lignin thermal analyses are reported. Six laboratories have conducted thermal analyses of four lignin types to determine their cp values and softening points, and to study the thermal behaviour, materials endo- and exotherms included. The lignin types examined were wood

  18. Calorimetry: Introduction, Overview and physics requirement at HL-LHC

    CERN Document Server

    Mannelli, M; The ATLAS collaboration

    2013-01-01

    We discuss how the HL-LHC luminosity target and Phase II physics goals drive the Calorimeter performance requirements of the LHC experiments, and motivate the program of Upgrades being developed to address these. Radiation damage to detector and electronics components will impose challenges to the operation of the existing calorimeter systems and will limit their lifetime. Instantaneous luminosities above the nominal LHC values may induce significant degradation in the response of some detectors (in particular in the forward region). To optimize the performance of the systems and cope with the physics goals in Phase-II the trigger system will set new requirements for the calorimeter readout.

  19. The effect of inoperative readout layers on SDC calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Green, D.

    1993-08-01

    The SDC calorimeter is to be constructed using Pb and Fe absorbers and scintillator active sampling using the tile/fiber technique. In this note, the effect of the inoperative readout of a single sampling layer is studied. The goal of this study is to inform on a cost/benefit analysis of the need to repair inoperative layers of the calorimetric readout.

  20. Surveying Temperature and Density Measurements in Nuclear Calorimetry

    Science.gov (United States)

    Raciti, G.; Bassini, R.; Begemann-Blaich, M.; Fritz, S.; Groß, C.; Immè, G.; Iori, I.; Lynen, U.; Mahi, M.; Möhlenkamp, T.; Müller, W. F. J.; Ocker, B.; Odeh, T.; Pochodzalla, J.; Riccobene, G.; Romano, F. P.; Saija, A.; Schwarz, C.; Serfling, V.; Schnittker, M.; Schüttauf, A.; Seidel, W.; Sfienti, C.; Trautmann, W.; Trzclnski, A.; Verde, G.; Xi, Hongfei; Zwieglinski, B.

    2001-11-01

    An experimental investigation on thermodynamical observables characterizing the conditions of multifragmenting systems is reported. High granularity hodoscopes allowed simultaneous measurements of isotopic and emission temperatures. HBT interferometry with light charged particles allowed radii measurements. The disagreement between the two temperature measurements could be related to the space-time evolution of the fragmentation process as confirmed by density measurements. The slope temperatures derived from the target spectator decay fragment energy spectra suggest a dependence on the Fermi motion within the initial system. The dependence of the Nuclear Caloric Curve on the mass of the systems was probed.

  1. Gamma-ray bursts: calorimetry on echoes in gravitational waves

    CERN Document Server

    Putten, M H

    2002-01-01

    Black hole-torus systems may represent astrophysical transient sources powered by the spin energy of a Kerr black hole. Equivalence in poloidal topology to pulsar magnetospheres suggests a long-lived state in suspended accretion when the black hole spins rapidly. The rotational energy is released in several channels: baryon-poor jets along open flux tubes extending from the horizon to infinity, gravitational radiation from the torus, winds and, conceivably, neutrino emissions. Gravitational radiation is expected to be representative of the rotational energy of the black hole, exceeding the output along the open flux tube by some two orders of magnitude. LIGO/VIRGO detections can hereby provide us with a calorimetric test of Kerr black holes.

  2. The colligative properties of fruit juices by photopyroelectric calorimetry

    Science.gov (United States)

    Frandas, A.; Surducan, V.; Nagy, G.; Bicanic, D.

    1999-03-01

    The photopyroelectric method was used to study the depression of freezing point in juices prepared from selected apple and orange juice concentrates. By using the models for real solutions, the effective molecular weight of the dissolved solids was obtained. The acids concentration in the fruit juice is reflected both in the equivalent molecular weight (by lowering it) and in the interaction coefficients b and C. Using the data for the molecular weight and the characteristic coefficients, prediction curves for the samples investigated can be used in practice. Freezing point depression can also be used as an indicator of the degree of spoilage of fruit juices.

  3. On the Interpretation of Low Temperature Calorimetry Data

    DEFF Research Database (Denmark)

    Kjeldsen, Ane Mette; Geiker, Mette Rica

    2008-01-01

    of ions on freezing point depression into account. It is proposed that the connectivity of pores, e.g. in cement-based materials, may be characterised based on cooling curves, whereas the pore size distribution may be characterised based on the heating curve. Cooling should be undertaken at a high rate...

  4. Textural Characterization and Energetics of Porous Solids by Adsorption Calorimetry

    Directory of Open Access Journals (Sweden)

    Vanessa Silenia Garcia-Cuello

    2011-06-01

    Full Text Available An adsorption microcalorimeter was designed and built in our laboratory and used for the determination of differential adsorption heats in different samples of porous solids: activated carbon granules, activated carbon pellets, an activated carbon monolith and a zeolite sample. This work shows the relationship between adsorption heat and the pore size of different porous solids using adsorption of NH3, CO and N2O. The result shows that the thermal effect can be related with textural properties and superficial chemical groups of the studied porous solids. The values of differential heats of N2O adsorption in the investigated systems have shown that this interaction is weaker than that with CO. Small amounts of N2O are chemisorbed in the investigated systems. For the room temperature adsorption of N2O, the strongest active sites for the interaction with Brönsted acid groups in the ACM structure were identified. The values determined are between −60 kJ/mol and −110 kJ/mol for ZMOR and ACM, respectively, for the adsorption of N2O and −95 kJ/mol and −130 kJ/mol for the adsorption of CO.

  5. Dual-readout calorimetry with lead tungstate crystals

    Science.gov (United States)

    Akchurin, N.; Berntzon, L.; Cardini, A.; Ferrari, R.; Gaudio, G.; Hauptman, J.; Kim, H.; La Rotonda, L.; Livan, M.; Meoni, E.; Paar, H.; Penzo, A.; Pinci, D.; Policicchio, A.; Popescu, S.; Susinno, G.; Roh, Y.; Vandelli, W.; Wigmans, R.

    2008-01-01

    Results are presented of beam tests in which a small electromagnetic calorimeter consisting of lead tungstate crystals was exposed to 50 GeV electrons and pions. This calorimeter was backed up by the DREAM Dual-Readout calorimeter, which measures the scintillation and Cherenkov light produced in the shower development, using two different media. The signals from the crystal calorimeter were analyzed in great detail in an attempt to determine the contributions from these two types of light to the signals, event by event. This information makes it possible to eliminate the dominating source of fluctuations and thus achieve an important improvement in hadronic calorimeter performance.

  6. Inorganic single crystalline fibers for dual-readout calorimetry

    CERN Document Server

    Pauwels, Kristof; Lecoq, Paul

    This thesis focuses on the improvement of the energy resolution of hadron calorimeters. The approach is based on dual-readout, which consists in the simultaneous detection of both scintillation and Cherenkov light. The comparison of these two signals allows a compensation of the energy fluctuations, which are inherent to the detection of hadronic showers. Lutetium aluminium garnets (LuAG), which are efficient scintillators when activated with rare-earth dopants (i.e. Cerium), can also act as Cherenkov radiators when undoped. Both undoped and doped crystals can then be assembled to build an efficient dual-readout calorimeter. With the objective to investigate the feasibility of this concept, the effects of the doping concentration and the use of various co-dopant on the light output and the timing properties of LuAG were studied. The growth method was demonstrated to induce significant differences in the nature and concentration of structural defects. The optimum geometry, which is based on single-crystals sha...

  7. Resistive Plate Chambers for Imaging Calorimetry - the DHCAL

    CERN Document Server

    Repond, Jose

    2014-01-01

    The DHCAL, the Digital Hadron Calorimeter, is a prototype calorimeter based on Resistive Plate Chambers (RPCs). The design emphasizes the imaging capabilities of the detector in an effort to optimize the calorimeter for the application of Particle Flow Algorithms (PFAs) to the reconstruction of hadronic jet energies in a colliding beam environment. The readout of the chambers is segmented into 1 x 1 cm2 pads, each read out with a 1-bit (single threshold) resolution. The prototype with approximately 500,000 readout channels underwent extensive testing in both the Fermilab and CERN test beams. This talk presents preliminary findings from the analysis of data collected at the test beams.

  8. Resistive Plate Chambers for imaging calorimetry — The DHCAL

    Science.gov (United States)

    Repond, J.

    2014-09-01

    The DHCAL — the Digital Hadron Calorimeter — is a prototype calorimeter based on Resistive Plate Chambers (RPCs). The design emphasizes the imaging capabilities of the detector in an effort to optimize the calorimeter for the application of Particle Flow Algorithms (PFAs) to the reconstruction of hadronic jet energies in a colliding beam environment. The readout of the chambers is segmented into 1 × 1 cm2 pads, each read out with a 1-bit (single threshold) resolution. The prototype with approximately 500,000 readout channels underwent extensive testing in both the Fermilab and CERN test beams. This talk presents preliminary findings from the analysis of data collected at the test beams.

  9. Calorimetry for Lepton Collider Experiments – CALICE results and activities

    CERN Document Server

    Adloff, C.; Chefdeville, M.; Drancourt, C.; Gaglione, R.; Geffroy, N.; Karyotakis, Y.; Koletsou, I.; Prast, J.; Vouters, G.; Bilki, B.; Cundiff, T.; De Lurgio, P.; Drake, G.; Francis, K.; Haberichter, B.; Guarino, V.; Kreps, A.; Repond, J.; Schlereth, J.; Skrzecz, F.; Smith, J.; Underwood, D.; Wood, K.; Xia, L.; Zhang, Q.; Zhao, A.; Price, T.; Watson, N.K.; Marshall, J.S.; Thomson, M.A.; Ward, D.R.; Benchekroun, D.; Hoummada, A.; Khoulaki, Y.; Apostolakis, J.; Arfaoui, S.; Benoit, M.; Dannheim, D.; Dotti, A.; Duarte Ramos, F.; Elsener, K.; Folger, G.; Gerwig, H.; Grefe, C.; Ivantchenko, V.; Killenberg, M.; Klempt, W.; Lam, C.B.; Linssen, L.; Lucaci-Timoce, A.I.; Muennich, A.; Nardulli, J.; Poss, S.; Roloff, P.; Sailer, A.; Schlatter, D.; Sicking, E.; Speckmayer, P.; Strube, J.; Uzhinskiy, V.; Gay, P.; Manen, S.; Royer, L.; Soumpholphakdy, X.; Cauwenbergh, S.; Tytgat, M.; Zaganidis, N.; Blazey, G.C.; Chakraborty, D.; Dyshkant, A.; Hedin, D.; Lima, J.G.R.; Salcido, R.; Zutshi, V.; Astakhov, V.; Babkin, V.A.; Bazylev, S.N.; Golovatyuk, S.; Golutvin, I.; Gorbunov, N.; Malakhov, A.; Slepnev, S.; Tyapkin, I.; Volgin, S.V.; Zanevski, Y.; Zintchenko, A.; Dzahini, D.; Gallin-Martel, L.; Giraud, J.; Grondin, D.; Hostachy, J.Y.; Menu, J.; Rarbi, F-E.; Cornett, U.; David, D.; Falley, G.; Gadow, K.; Gottlicher, P.; Gunter, C.; Hermberg, B.; Karstensen, S.; Krivan, F.; Kruger, K.; Lu, S.; Lutz, B.; Morozov, S.; Morgunov, V.; Reinecke, M.; Sefkow, F.; Smirnov, P.; Terwort, M.; Vargas-Trevino, A.; Feege, N.; Garutti, E.; Laurien, S.; Marchesini, I.; Ramilli, M.; Eckert, P.; Harion, T.; Shen, W.; Stamen, R.; Wilson, G.W.; Kawagoe, K.; Miyazaki, Y.; Oishi, K.; Sudo, Y.; Ueno, H.; Yoshioka, T.; Dauncey, P.D.; Postranecky, M.; Warren, M.; Wing, M.; Cortina Gil, E.; Mannai, S.; Bonnevaux, A.; Combaret, C.; Caponetto, L.; Grenier, G.; Han, R.; Ianigro, J.C.; Kieffer, R.; Laktineh, I.; Lumb, N.; Mathez, H.; Mirabito, L.; Steen, A.; Berenguer Antequera, J.; Calvo Alamillo, E.; Fouz, M.C.; Marin, J.; Puerta-Pelayo, J.; Verdugo, A.; Buscher, V.; Masetti, L.; Schafer, U.; Tapprogge, S.; Wanke, R.; Welker, A.; Corriveau, F.; Bobchenko, B.; Chadeeva, M.; Danilov, M.; Epifantsev, A.; Markin, O.; Mizuk, R.; Novikov, E.; Popov, V.; Rusinov, V.; Tarkovsky, E.; Andreev, V.; Kirikova, N.; Komar, A.; Kozlov, V.; Negodaev, M.; Smirnov, P.; Soloviev, Y.; Terkulov, A.; Buzhan, P.; Ilyin, A.; Kantserov, V.; Kaplin, V.; Karakash, A.; Popova, E.; Smirnov, S.; Baranova, N.; Boos, E.; d; Gladilin, L.; Karmanov, D.; Korolev, M.; Merkin, M.; Savin, A.; Voronin, A.; Kiesling, C.; Seidel, K.; Simon, F.; Soldner, C.; Szalay, M.; Tesar, M.; Weuste, L.; Augustin, J-E.; David, J.; Ghislain, P.; Lacour, D.; Lavergne, L.; Amjad, M.S.; Bonis, J.; Bouquet, B.; Callier, S.; Conforti, S.; Cornebise, P.; Dulucq, F.; Faucci Giannelli, M.; Fleury, J.; Frisson, T.; Guilhem, G.; Li, H.; Martin-Chassard, G.; Richard, F.; Poeschl, R.; Raux, L.; Rouene, J.; Seguin-Moreau, N.; Wicek, F.; Zhang, Z.; Anduze, M.; Belkadhi, K.; Boudry, V.; Brient, J-C.; Cerutti, M.; Clerc, C.; Cornat, R.; Decotigny, D.; Frotin, M.; Gastaldi, F.; Guliyev, E.; Haddad, Y.; Jeans, D.; Magniette, F.; Matthieu, A.; Mora, P.; Musat, G.; Roche, N.; Ruan, M.; Tran, T.H.; Videau, H.; Bulanek, B.; Zacek, J.; Carna, M.; Gallus, P.; Lednicky, D.; Tomasek, L.; Tomasek, M.; Cvach, J.; Havranek, M.; Janata, M.; Kvasnicka, J.; Marcisovsky, M.; Polak, I.; Popule, J.; Sicho, P.; Smolik, J.; Vrba, V.; Zalesak, J.; Gapienko, V.; Semak, A.; Ukhanov, M.; Belhorma, B.; Ghazlane, H.; Hamasaki, R.; Ide, H.; Inayoshi, S.; Itoh, S.; Kawakami, Y.; Kobayashi, A.; Kotera, K.; Nishiyama, M.; Obe, S.; Ono, H.; Ogawa, T.; Ohtsuka, N.; Sakuma, T.; Sato, H.; Takeshita, T.; Totsuka, S.; Tsubokawa, T.; Yanagida, K.; Yamaura, W.; Khan, A.; Kim, D.H.; Kong, D.J.; Oh, Y.D.; Uozumi, S.; Yang, Y.; Fuchi, R.; Ukegawa, F.; Gotze, M.; Hartbrich, O.; Sauer, J.; Weber, S.; Zeitnitz, C.

    2012-01-01

    The CALICE collaboration conducts calorimeter R&D for highly granular calorimeters, mainly for their application in detectors for a future lepton collider at the TeV scale. The activities ranges from generic R&D with small devices up to extensive beam tests with prototypes comprising up to several 100000 calorimeter cells. CALICE has validated the performance of particle flow algorithms with test beam data and delivers the proof of principle that highly granular calorimeters can be built, operated and understood. The successes achieved in the past years allows the step from prototypes to calorimeter systems for particle physics detectors to be addressed.

  10. Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry

    Directory of Open Access Journals (Sweden)

    V. Garcia-Cuello

    2008-01-01

    Full Text Available An adsorption microcalorimeter for the simultaneous determination of the differential heat of adsorption and the adsorption isotherm for gas-solid systems are designed, built, and tested. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K=154.34±0.23 WV−1. The adsorption microcalorimeter is used to obtain adsorption isotherms and the corresponding differential heats for the adsorption of CO2 on a reference solid, such as a NaZSM-5 type zeolite. Results for the behavior of this system are compared with those obtained with commercial equipment and with other studies in the literature.

  11. Noble Liquid (Xenon or Krypton) Totally Active Calorimetry

    CERN Multimedia

    2002-01-01

    Main Goals\\\\ \\\\ Determine ionization and scintillation yields in liquid Xenon (LXe) or Krypton.\\\\ \\\\ Determine the electron lifetime and photon mean free path in LXe or LKr. \\\\ \\\\ Determine energy resolution of LXe or LKr via ionization or scintillation.\\\\ \\\\ Determine correlation of fluctuations between ionization and scintillation. Summary of Results \\\\ \\\\ -~measured the electron lifetime in LXe, ($\\tau$~$>$~400 $\\mu$s).\\\\ \\\\ -~measured the energy to create an ionization electron in LXe, W=9.8 eV.\\\\ \\\\ -~measured the energy to create a LXe scintillation photon, W$ _{s} $~=~14.2~eV. \\\\ \\\\ -~measured the anticorrelation of scintillation and ionization yields. \\\\ \\\\ -~measured the energy resolution in LXe via ionization, $ sigma _{E} / $E=0.07\\%/$\\sqrt$E(GeV). \\\\ \\\\ -~measured resolution in LXe via scintillation $ sigma _{E} / $E=0.24\\%/$\\sqrt$E(GeV)+0.26\\%. \\\\ \\\\ -~measured electron drift velocity in LXe:~neat (2.5 mm/$\\mu$s), doped (4.4~mm/$\\mu$s). \\\\ \\\\ -~measured the photon mean free path in LXe vs $ lambd...

  12. Precision Timing with Silicon Sensors for Use in Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bornheim, A. [Caltech; Ronzhin, A. [Fermilab; Kim, H. [Chicago U.; Bolla, G. [Fermilab; Pena, C. [Caltech; Xie, S. [Caltech; Apresyan, A. [Caltech; Los, S. [Fermilab; Spiropulu, M. [Caltech; Ramberg, E. [Fermilab

    2017-11-27

    The high luminosity upgrade of the Large Hadron Collider (HL-LHC) at CERN is expected to provide instantaneous luminosities of 5 × 1034 cm-2 s-1. The high luminosities expected at the HL-LHC will be accompanied by a factor of 5 to 10 more pileup compared with LHC conditions in 2015, causing general confusion for particle identification and event reconstruction. Precision timing allows to extend calorimetric measurements into such a high density environment by subtracting the energy deposits from pileup interactions. Calorimeters employing silicon as the active component have recently become a popular choice for the HL- LHC and future collider experiments which face very high radiation environments. We present studies of basic calorimetric and precision timing measurements using a prototype composed of tungsten absorber and silicon sensor as the active medium. We show that for the bulk of electromagnetic showers induced by electrons in the range of 20 GeV to 30 GeV, we can achieve time resolutions better than 25 ps per single pad sensor.

  13. Dual-Readout Calorimetry for High-Quality Energy Measurements

    CERN Document Server

    Wigmans, R

    2010-01-01

    During the past seven years, the DREAM Collaboration has systematically investigated all factors that determine and limit the precision with which the properties of hadrons and jets can be measured in calorimeters. Using simultaneous detection of the deposited energy and the Cerenkov light produced in hadronic shower development (dual readout), the fluctuations in the electromagnetic shower fraction could be measured event by event and their effects on signal linearity, response function and energy resolution eliminated. Detailed measurement of the time structure of the signals made it possible to measure the contributions of nuclear evaporation to the signals and thus reduce the effects of fluctuations in “invisible energy”. We are now embarking on the construction of a full-scale calorimeter which incorporates all these elements and which should make it possible to measure the four-vectors of both electrons, hadrons and jets with very high precision, in an instrument that can be simply calibrated with e...

  14. Investigation of binary solid phases by calorimetry and kinetic modelling

    NARCIS (Netherlands)

    Matovic, M.

    2007-01-01

    The traditional methods for the determination of liquid-solid phase diagrams are based on the assumption that the overall equilibrium is established between the phases. However, the result of the crystallization of a liquid mixture will typically be a non-equilibrium or metastable state of the

  15. Academic Genealogy and Direct Calorimetry: A Personal Account

    Science.gov (United States)

    Jackson, Donald C.

    2011-01-01

    Each of us as a scientist has an academic legacy that consists of our mentors and their mentors continuing back for many generations. Here, I describe two genealogies of my own: one through my PhD advisor, H. T. (Ted) Hammel, and the other through my postdoctoral mentor, Knut Schmidt-Nielsen. Each of these pathways includes distingished scientists…

  16. Metabolic depression in fish measured by direct calorimetry: A review

    NARCIS (Netherlands)

    Ginneken, van V.J.T.; Thillart, van den G.

    2009-01-01

    In nature under adverse conditions like low oxygen conditions or starvation fish often lower their metabolism: `metabolic depression¿. This strategy of lowering the metabolic rate is a survival strategy and is used to save energy stores and diminish end-product accumulation. The overall metabolic

  17. Calorimetry and thermodynamic aspects of heterotrophic, mixotrophic, and phototrophic growth

    NARCIS (Netherlands)

    Stockar, von U.; Marison, I.; Janssen, M.G.J.; Patino, R.

    2011-01-01

    A simple stoichiometric model is proposed linking the biomass yield to the enthalpy and Gibbs energy changes in chemo-heterotrophic, mixotrophic, and photo-autotrophic microbial growth. A comparison with calorimetric experiments on the algae Chlorella vulgaris and Chlorella sorokiniana confirmed the

  18. High throughput calorimetry for evaluating enzymatic reactions generating phosphate.

    Science.gov (United States)

    Hoflack, Lieve; De Groeve, Manu; Desmet, Tom; Van Gerwen, Peter; Soetaert, Wim

    2010-05-01

    A calorimetric assay is described for the high-throughput screening of enzymes that produce inorganic phosphate. In the current example, cellobiose phosphorylase (EC 2.4.1.20) is tested for its ability to synthesise rare disaccharides. The generated phosphate is measured in a high-throughput calorimeter by coupling the reaction to pyruvate oxidase and catalase. This procedure allows for the simultaneous analysis of 48 reactions in microtiter plate format and has been validated by comparison with a colorimetric phosphate assay. The proposed assay has a coefficient of variation of 3.14% and is useful for screening enzyme libraries for enhanced activity and substrate libraries for enzyme promiscuity.

  19. Determination of Differential Enthalpy and Isotherm by Adsorption Calorimetry

    OpenAIRE

    Garcia-Cuello, V.; Moreno-Piraján, J. C; Giraldo-Gutiérrez, L.; K. Sapag; Zgrablich, G.

    2008-01-01

    An adsorption microcalorimeter for the simultaneous determination of the differential heat of adsorption and the adsorption isotherm for gas-solid systems are designed, built, and tested. For this purpose, a Calvet heat-conducting microcalorimeter is developed and is connected to a gas volumetric unit built in stainless steel to record adsorption isotherms. The microcalorimeter is electrically calibrated to establish its sensitivity and reproducibility, obtaining K=154.34±0.23 WV−1. The adsor...

  20. Mathematical analysis for radiometric calorimetry of a radiating sphere

    Science.gov (United States)

    Schmid, L. A.

    1982-01-01

    Equations are derived from which the temperature dependence of both the specific heat and the thermal diffusivity of a spherical sample of material can be calculated from observations of the time dependence of the surface temperature and the time-rate of energy loss from the sample as it cools. The derivation takes into account the nonuniformity of the interior temperature field of the sample, and the resulting equations can be applied not only to radiative cooling, but also to any other cooling mechanism that does not violate the assumed spherical symmetry. The analysis excludes change of phase, but it does take thermal expansion into account. To permit the making of estimates necessary for the design of radiative cooling experiments, a universal temperature-time cooling curve is derived for the post-transient cooling regime of a radiating sphere of any size with arbitrary, but constant, thermal parameters.

  1. A hybrid training method for neural energy estimation in calorimetry

    CERN Document Server

    Da Silva, P V M; Seixas, J

    2001-01-01

    A neural mapping is developed to improve the overall performance of Tilecal, which is the hadronic calorimeter of the ATLAS detector. Feeding the input nodes of a multilayer feedforward neural network with the energy values sampled by the calorimeter cells in beam tests, it is shown that the original energy scale of pion beams is reconstructed over a wide energy range and linearity is significantly improved. As it happens for classical methods, a compromise between nonlinearity correction and the optimization of the energy resolution of the detector has to be accomplished. A hybrid training method for the neural mapping is proposed to achieve this design goal. Using the backpropagation algorithm, the method intercalates an epoch of training steps, for which the neural mapping mainly focus on linearity correction, with another block of training steps, in which the original energy resolution obtained by linearly combining the calorimeter cells becomes the main target. (6 refs).

  2. The Critical Micelle Concentration of Asphaltenes as Measured by Calorimetry

    DEFF Research Database (Denmark)

    Andersen, Simon Ivar; Christensen, S. D.

    2000-01-01

    of asphaltenes obtained by solvent extraction with toluene/heptane mixtures. These subfractions get more complex in structure as the toluene content of the extraction solvent increases and at the same time the CMC of the asphaltenes in pure toluene decreases. There is an indication that the presence of "lower...

  3. INDIRECT CALORIMETRY DURING ULTRADISTANCE RUNNING: A CASE REPORT

    Directory of Open Access Journals (Sweden)

    Charles L. Dumke

    2006-12-01

    Full Text Available The purpose was to determine the energy expenditure during ultradistance trail running. A portable metabolic unit was carried by a male subject for the first 64.5 km portion of the Western States 100 running race. Calibrations were done with known gases and volumes at ambient temperature, humidity and pressure (23-40.5 °C and 16-40% respectively. Altitude averaged 1692.8 ± 210 m during data collection. The male subject (36 yrs, 75 kg, VO2max of 67.0 ml·kg-1·min-1 had an average (mean ± SD heart rate of 132 ± 9 bpm, oxygen consumption of 34.0 ± 6.8 ml·kg-1·min-1, RER of 0.91 ± 0.04, and VE of 86.0 ± 14.3 L·min-1 during the 21.7 km measuring period. This represented an average of 51% VO2max and 75% heart rate maximum. Energy expenditure was 12.6 ± 2.5 kcals·min-1, or 82.7 ± 16.6 kcals·km-1 (134 ± 27 kcals·mile-1 at 68.3 ± 12.5% carbohydrate. Extrapolation of this data would result in an energy expenditure of >13,000 kcals for the 160 km race, and an exogenous carbohydrate requirement of >250 kcal·hr-1. The energy cost of running for this subject on separate, noncompetitive occasions ranged from 64.9 ± 8.5 to 74.4 ± 5.5 kcals·km-1 (105 ± 14 to 120 ± 9 kcals·mile-1. Ultradistance trail running increases energy expenditure above that of running on nonundulating terrain, which may result in underestimating energy requirements during these events and subsequent undernourishment and suboptimal performance.

  4. Tritium measurement technique using ``in-bed`` calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Klein, J.E.; Mallory, M.K.; Nobile, A. Jr.

    1991-12-31

    One of the new technologies that has been introduced to the Savannah River Site (SRS) is the production scale use of metal hydride technology to store, pump, and compress hydrogen isotopes. For tritium stored in metal hydride storage beds, a unique relationship does not exist between the amount of tritium in the bed and the pressure-volume-temperature properties of the hydride material. Determining the amount of tritium in a hydride bed after desorbing the contents of the bed to a tank and performing pressure, volume, temperature, and composition (PVTC) measurements is not practical due to long desorption/absorption times and the inability to remove tritium ``heels`` from the metal hydride materials under normal processing conditions. To eliminate the need to remove tritium from hydride storage beds for measurement purposes, and ``in-bed`` tritium calorimetric measurement technique has been developed. The steady-state temperature rise of a gas stream flowing through a jacketed metal hydride storage bed is measured and correlated with power input to electric heaters used to simulate the radiolytic power generated by the decay of tritium to {sup 3}He. Temperature rise results for prototype metal hydride storage beds and the effects of using different gases in the bed are shown. Linear regression results shows that for 95% confidence intervals, temperature rise measurements can be obtained in 14 hours and have an accuracy of {plus_minus}1.6% of a tritium filled hydride storage bed.

  5. Isothermal titration calorimetry of sorption processes. A promising approach

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Norbert; Foerstendorf, Harald [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Surface Processes; Drobot, B. [Technische Univ. Dresden (Germany); Fahmy, Karim [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biophysics; Reder, Christian

    2017-06-01

    As a consequence of nuclear waste disintegration heat, elevated temperatures in the near field may influence radionuclide retention significantly. However, there is a nearly complete lack of spectroscopic investigations of sorption processes at elevated temperatures. In addition, experimental data on free Gibbs energy (Δ{sub R}G), enthalpy (Δ{sub R}H) and entropy (Δ{sub R}S) of reactions of most radionuclides including fission products such as {sup 79}Se are sparse. Using the Se(IV)/hematite system, we show that microcalorimetry can provide these thermodynamic parameters with high accuracy and in a manner that allows studying various radionuclides.

  6. LuAG:Ce fibers for high energy calorimetry

    CERN Document Server

    Dujardin, C; Ledoux, G; Perrodin, D; Ovanesyan, K L; Amans, D; Abler, D; Petrosyan, A; Auffray, E; Mancini, C

    2010-01-01

    The main objective of this contribution is to point out the potentialities of cerium doped LuAG single crystal as pixels and fibers. We first show that after optimization of growth conditions using Bridgman technology, this composition exhibits very good performances for scintillating applications (up to 26 000 photons/MeV). When grown with the micropulling down technology, fiber shapes can be obtained while the intrinsic performances are preserved. For the future high energy experiments requiring new detector concepts capable of delivering much richer informations about x- or gamma-ray energy deposition, unusual fiber shaped dense materials need to be developed. We demonstrate in this frame that cerium doped LuAG is a serious candidate for the next generation of ionizing radiation calorimeters. (C) 2010 American Institute of Physics. {[}doi: 10.1063/1.3452358

  7. Entalpía de disolución de sulfacetamida sódica en agua: comparación entre la calorimetría isoperibólica de solución y el método de van't Hoff Dissolution enthalpy of sodium sulfacetamide in water: comparison between solution isoperibolic calorimetry and the van't Hoff method

    Directory of Open Access Journals (Sweden)

    Daniel R. Torres

    2008-01-01

    Full Text Available The dissolution enthalpy (ΔH0soln of sodium sulfacetamide in water was determined by means of isoperibolic solution calorimetry. It was found that ΔH0soln diminishes as the drug concentration increases. Otherwise, the calorimetric values obtained as a function of the drug concentration were significantly different than those predicted by the van't Hoff method. It was demonstrated that the later is not a fully reliable method for the determination of ΔH0soln values in the specific case of highly soluble sodium salts. The observed phenomenon could be explained by the presence of strong solute-solute interactions at high salt concentrations, in addition to solute-solvent and solvent-solvent interactions.

  8. Estudo de soluções aquosas de copolímeros em bloco de poli(óxido de etileno-poli(óxido de propileno utilizando calorimetria exploratória diferencial (DSC Study of poly(ethylene oxide-b-propylene oxide block copolymers in aqueous solutions by differential scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Claudia R. E. Mansur

    1999-06-01

    Full Text Available O comportamento de sistemas aquosos contendo copolímeros dibloco monofuncionais de poli(óxido de etileno-poli(óxido de propileno, bloqueados em uma das extremidades da cadeia com segmento hidrocarbônico linear, foi avaliado através de calorimetria exploratória diferencial (DSC. Transições endotérmicas foram observadas no aquecimento das soluções dos copolímeros e as temperaturas iniciais destas transições estão de acordo com os pontos de turvação dos copolímeros estudados. Nas curvas de resfriamento, são observadas duas transições, e quanto mais rápido é resfriada a solução de copolímero, melhor é observada a transição que deve estar relacionada à formação das micelas. A influência da presença de um agente hidrotrópico também foi avaliada em todas as soluções de copolímeros por meio do aumento no ponto de turvação com o aumento da concentração do agente hidrotrópico, visto que os picos endotérmicos foram deslocados para temperaturas mais altas.The behavior of aqueous systems containing block copolymers of poly(ethylene oxide (PEO and poly(propylene oxide (PPO, coupled to hydrocarbon groups, was evaluated by differential scanning calorimetry (DSC. Endothermic transitions in the copolymer solutions were observed under a linear heating rate and the initial temperatures of these transitions are in agreement with the cloud points of the copolymers studied. Two transitions were observed in the cooling curves; these transitions were better defined at faster cooling rates of the copolymer solutions which can be related to the micelles formation. The effect of the increasing concentration of the hydrotropic agent, sodium p-toluenesulfonate (NaPTS, in the copolymer solutions was observed by the increase in the cloud points given by the dislocation of the endothermic peaks to higher temperatures.

  9. Estudio de la reacción de curado del sistema éter diglicidílico del bisfenol-A (DGEBA y la dietilentriamina (DETA por calorimetría diferencial de barrido The curing reaction of diglycidyl ether of bisphenol-A (DGEBA and diethylentriamine system studied by differencial scanning calorimetry

    Directory of Open Access Journals (Sweden)

    Filiberto González Garcia

    2000-12-01

    Full Text Available La reacción de curado del sistema compuesto por el éter diglicidílico del bisfenol-A (DGEBA y la dietilentriamina (DETA fue estudiada por calorimetría diferencial de barrido (DSC. Diferentes expresiones cinéticas fueron encontradas por experimentos isotérmicos y dinámicos las que justifican cambios mecanísticos con la temperatura de cura. La cinética de la reacción cumple un segundo orden cinético con una energía de activación de 90 kJ mol-1 a altas temperaturas (mecanismo no catalítico. La cinética de la reacción a bajas temperaturas manifestó la existencia de dos mecanismos competitivos, se determinaron las constantes de velocidades de reacción a 60 y 70ºC y se encontró una energía de activación en el rango de 56.9 a 63.0 kJ mol¹, que está en perfecto acuerdo con la reportada a bajas temperaturas (mecanismo autocatalítico. También se muestra el diagrama de fases del sistema.The curing reaction of diglycidyl ether of bisphenol-A (DGEBA and diethylentriamine (DETA system was studied by differential scanning calorimetry (DSC. Different kinetics expressions were found by isothermal and dynamic experiments that they justify mechanism changes with the temperature. The reaction follows a second order kinetics and has activation energy of 90 kJ mol-1 at high temperatures (non-catalytic mechanism. The kinetics of the reactions at low temperatures manifested the existence of two competitive mechanisms, the constants rate were determined at 60 and 70°C and has activation energy in the range of 56.9 to 63.0 kJ mol-1 that is in perfect agreement with the reported to low temperatures (autocatalytic mechanism .

  10. Estudio cinético del efecto de polifenilsulfona sobre el curado de una resina epoxi/amina mediante calorimetría diferencial de barrido convencional y modulada con temperatura: parte II Kinetic study on the effect of curing polyphenylsulfone epoxy resin/amina by differential calorimetry scanning conventional and modulated temperature: part II

    Directory of Open Access Journals (Sweden)

    Asdrúbal J. Cedeño

    2010-01-01

    Full Text Available En este trabajo se estudió el efecto de la adición del termoplástico lineal polifenilsulfona (PPSU, sobre la cinética de reacción y las propiedades térmicas de una resina epoxídica basada en diglicidil éter de bisfenol - A (DGEBA, curada con diaminodifenilsulfona (DDS. El estudio cinético y la caracterización se realizaron mediante calorimetría diferencial de barrido, DSC estándar y modulado, bajo condiciones isotérmicas y dinámicas. La cinética del curado se discutió en el marco de tres modelos cinéticos: Kissinger, Flynn-Wall-Ozawa y el modelo cinético de orden n. Para describir la reacción de curado en su última etapa, se usó la relación semiempírica propuesta por Chern y Poehlein para considerar la influencia de la difusión sobre la rapidez de reacción. El mecanismo de curado, para todos los sistemas, se ajustó a una cinética de orden n, a pesar del contenido de PPSU, y se observó que éste se hace muy controlado por la difusión conforme aumenta el contenido de PPSU y conforme la temperatura de curado disminuye. El tiempo de vitrificación de los sistemas exhibió una fuerte dependencia con el contenido de PPSU.In this work we studied the effect of the addition of the linear thermoplastic polyphenyl sulfone (PPSU on the cure kinetics and the thermal properties of a resin based on diglycidyl ether of bisphenol-A (DGEBA, cured with 4,4´-diaminodiphenyl sulfone (DDS. The kinetic study and the characterization process have been carried out by using differential scanning calorimetry, DSC, and temperature modulated DSC (TMDSC, under isothermal and dynamic conditions. The curing kinetics was discussed in the framework of three kinetic models: Kissinger, Flynn-Wall-Ozawa, and the model of reaction of order n. To describe the cured reaction in its last stage, we have used the semiempirical relationship proposed by Chern and Poehlein to take into account the influence of diffusion on the reaction rate. The cure mechanism

  11. Experiências simultâneas de espalhamento de raios X e calorimetria diferencial de varredura (SAXS/WAXD/DSC com resolução temporal utilizando radiação síncrotron Simultaneous and time resolved X-ray scattering and differential Scanning calorimetry experiments (SAXS/WAXD/DSC using synchrotron radiation

    Directory of Open Access Journals (Sweden)

    Tomás S. Plivelic

    2005-07-01

    Full Text Available Neste trabalho apresentamos uma nova instrumentação instalada na linha de SAXS do LNLS. Este equipamento permite a realização de experimentos simultâneos e resolvidos no tempo de espalhamento de raios X a baixos e altos ângulos (SAXS/WAXD e calorimetria diferencial de varredura (DSC. O dispositivo de DSC mostrou-se comparável a equipamentos convencionais, com taxas de variação de temperatura de até 60 °C/min e uma precisão de 0.1 °C. O uso de uma fonte de radiação síncrotron e de detetores de raios X sensíveis à posição permitiu a obtenção de dados com uma resolução temporal de 30 s. A aplicação deste arranjo experimental no estudo da cristalização isotérmica e da fusão em materiais poliméricos é mostrada para o caso da policaprolactona (PCL e suas blendas com polietileno clorado (PCL/PECl. As experiências mostraram a formação simultânea da estrutura cristalina e da morfologia lamelar nos diferentes estágios da cristalização assim como mudanças na cinética do processo com o tratamento isotérmico e a composição da blenda. Finalmente cabe destacar que experimentos simultâneos de SAXS/WAXD/DSC permitem o estudo de distintos processos abrangendo não apenas os de cristalização, mas também a formação de colóides e géis ou as transições de fase estruturais em diversos materiais.New instrumentation designed to perform simultaneous time-resolved X-ray scattering experiments at small and wide angles (SAXS/WAXD as well as differential scanning calorimetry (DSC has recently been installed at the SAXS beamline of the Laboratório Nacional de Luz Síncrotron. The DSC device proved to be comparable with conventional equipment, allowing temperature variation with rates of up to 60 °C/min with precision of 0.1 °C. The use of a synchrotron radiation source and position sensitive X-ray detectors allows data collection in real time with 30 s resolution. The application of this experimental set-up in the

  12. Investigação da cinética de cura por calorimetria diferencial exploratória (DSC de resinas epóxi preparadas a partir de óleo de soja epoxidado com diferentes anidridos e aminas terciárias Investigation of the kinetics of cure by differential scanning calorimetry (DSC of epoxy resins prepared from epoxidized soybean oil with different anhydrides and tertiary amines

    Directory of Open Access Journals (Sweden)

    Ana P. O. Costa

    2011-01-01

    Full Text Available No presente trabalho, utilizou-se a calorimetria diferencial exploratória (DSC para investigar a cinética da reação de cura de resinas epóxi produzidas a partir da reação do óleo de soja epoxidado (ESO, com os anidridos dodecenilsuccínico (DDS, maleico (MAL, ftálico (FTA, succínico (SUC e hexahidroftálico (CH, atuando como agentes de cura, e na presença de aminas terciárias como a trietilamina (TEA, a N,N'-dimetilanilina (ARO e a 1,4- diazobiciclo [2,2,2] octano (DABCO, atuando como catalisadores. A taxa de aquecimento, a natureza química e a estrutura do anidrido e das aminas influenciaram a reação de cura. Os métodos dinâmicos de Kissinger, Ozawa e de Barrett foram utilizados para calcular a energia de ativação dos sistemas onde se variou o anidrido. Observou-se que os anidridos mais reativos foram o DDS e maleico que apresentaram os menores valores de energias de ativação. No estudo da influência do catalisador, utilizou-se o método de Barrett para determinar as energias de ativação das reações com as diferentes aminas. A amina cicloaliafática (DABCO foi a mais reativa obtendo-se o menor valor de energia de ativação (Ea = 51 kJ.mol-1 e fator pré-exponencial (ln A0 = 9 s-1.In the present work, differential scanning calorimetry (DSC was used to investigate the curing reaction kinetics of epoxy resins produced from reaction of epoxidized soybean oil (ESO with cyclic anhydrides dodecenylsuccinic (DDS, maleic (MAL, phthalic (PA, succinic (SUC and hexahydrophthalic (CH, in the presence of tertiary amines such as triethylamine (TEA, N,N-dimethylaniline (ARO and 1,4-diazabicyclo [2,2,2] octane (DABCO. The heating rate, the nature and structure of anhydrides and amines were found to affect the curing reaction. The dynamic methods of Kissinger, Ozawa and Barrett were used to calculate the activation energy of the reactions where different anhydrides were used. DDS and maleic anhydrides were more reactive than the others

  13. RD52 Progress Report 2017: Dual-Readout Calorimetry for High-Quality Energy Measurements

    CERN Document Server

    Wigmans, R

    2017-01-01

    This document constitutes the sixth RD52 progress report. In this report, we describe our activities since the last time we reported to the SPS Committee (April 19, 2016), as well as our future plans.

  14. RD52 Progress Report 2016: Dual-Readout Calorimetry for High-Quality Energy Measurements

    CERN Document Server

    Wigmans, Richard

    2016-01-01

    This document constitutes the fifth RD52 progress report. In this report, we describe our activities since the last time we reported to the SPS Committee (April 14, 2015), as well as our future plans.

  15. The CMS ECAL Upgrade for Precision Crystal Calorimetry at the HL-LHC

    CERN Document Server

    Marinelli, Nancy

    2017-01-01

    The Compact Muon Solenoid Experiment (CMS) is operating at the Large Hadron Collider (LHC) with proton-proton collisions at 13 TeV center-of-mass energy and at a bunch spacing of 25 ns. New further challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL--LHC). The CMS electromagnetic calorimeter (ECAL) will need to be upgraded to substain the hardned environment.The design and R\\ and D studies for the ECAL upgrade are presented together with first test beam studies. Particular challenges at HL--LHC are the harsh radiation environment, the increasing data rates and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. Precision timing can be exploited to reduce the effect of the pile-up. Time resolution measurementscarried out during test-beams are shown. Plans are also shown for R\\ and D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL--LHC

  16. Intelum project: tackling the calorimetry challenge for future high-energy colliders

    CERN Multimedia

    CERN Bulletin

    2015-01-01

    Intelum is one of the CERN-coordinated projects funded under H2020. It aims to develop low-cost, radiation-hard scintillating and Cherenkov crystal and glass fibres for the next generation of calorimeter detectors for future high-energy experiments. This new technology could also have important applications in the medical imaging field.     Intelum project partners at the kick-off meeting held on 11 March at CERN.   Intelum is an H2020 Marie Skłodowska-Curie Research and Innovation Staff Exchange (RISE) project coordinated by CERN. This project was initiated by the Crystal Clear Collaboration (CERN’s RD18 experiment), which has been developing inorganic scintillation materials for novel ionising-radiation detectors for 25 years. Intelum is an international consortium including fifteen institutes and companies from across western and eastern Europe, Japan and the USA, all of which are experts in crystal growth, scintillating mechanisms, radiation damage and dete...

  17. Crystallization Kinetics of GeSbTe Phase-Change Nanoparticles Resolved by Ultrafast Calorimetry

    NARCIS (Netherlands)

    Chen, Bin; Brink, ten Gert; Palasantzas, Georgios; Kooi, Bart J.

    2017-01-01

    Although nanostructured phase-change materials (PCMs) are considered as the building blocks of next-generation phase-change memory and other emerging optoelectronic applications, the kinetics of the crystallization, the central property in switching, remains ambiguous in the high-temperature regime.

  18. Computational Calorimetry: High-Precision Calculation of Host-Guest Binding Thermodynamics.

    Science.gov (United States)

    Henriksen, Niel M; Fenley, Andrew T; Gilson, Michael K

    2015-09-08

    We present a strategy for carrying out high-precision calculations of binding free energy and binding enthalpy values from molecular dynamics simulations with explicit solvent. The approach is used to calculate the thermodynamic profiles for binding of nine small molecule guests to either the cucurbit[7]uril (CB7) or β-cyclodextrin (βCD) host. For these systems, calculations using commodity hardware can yield binding free energy and binding enthalpy values with a precision of ∼0.5 kcal/mol (95% CI) in a matter of days. Crucially, the self-consistency of the approach is established by calculating the binding enthalpy directly, via end point potential energy calculations, and indirectly, via the temperature dependence of the binding free energy, i.e., by the van't Hoff equation. Excellent agreement between the direct and van't Hoff methods is demonstrated for both host-guest systems and an ion-pair model system for which particularly well-converged results are attainable. Additionally, we find that hydrogen mass repartitioning allows marked acceleration of the calculations with no discernible cost in precision or accuracy. Finally, we provide guidance for accurately assessing numerical uncertainty of the results in settings where complex correlations in the time series can pose challenges to statistical analysis. The routine nature and high precision of these binding calculations opens the possibility of including measured binding thermodynamics as target data in force field optimization so that simulations may be used to reliably interpret experimental data and guide molecular design.

  19. Study of the thermal behavior of azidohetarenes with differential scanning calorimetry.

    Science.gov (United States)

    Stadlbauer, Wolfgang; Hojas, Gerhard

    2002-01-01

    Thermal properties of azidohetarenes without reactive ortho-substituents, obtained by DSC analysis, were compared with the DSC data of ortho-phenyl and ortho-acyl substituted azidohetarenes, which give ring closure reactions either to indoles or to five-membered heterocycles such as isoxazoles. The reaction temperatures and reaction enthalpies give both information to prepare the reaction conditions and important safety information and were, in addition, used to find out relations between the temperatures or enthalpies with the three different reaction mechanisms.

  20. Estimation of the Polymerization Rate of Liquid Propylene Using Adiabatic Reaction Calorimetry and Reaction Dilatometry

    NARCIS (Netherlands)

    Ali, Mohammad Al-haj; Betlem, Bernardus H.L.; Roffel, B.; Weickert, G.

    2007-01-01

    The use of pressure-drop and constant-pressure dilatometry for obtaining rate data for liquid propylene polymerization in filled batch reactors was examined. The first method uses reaction temperature and pressure as well as the compressibility of the reactor contents to calculate the polymerization

  1. Impregnation of mesoporous silica for catalyst preparation studied with differential scanning calorimetry

    NARCIS (Netherlands)

    Eggenhuisen, T.M.|info:eu-repo/dai/nl/313959498; van Steenbergen, M.J.|info:eu-repo/dai/nl/304839302; Talsma, H.|info:eu-repo/dai/nl/08138212X; de Jongh, P.E.|info:eu-repo/dai/nl/186125372; de Jong, K.P.|info:eu-repo/dai/nl/06885580X

    2009-01-01

    Aqueous impregnation of mesoporous silica as a first step in catalyst preparation was studied to investigate the distribution of the metal-precursor solution over the support. The degree of pore-filling after impregnation was determined using the freezing point depression of confined liquids. A

  2. Differential scanning calorimetry of the effects of temperature and humidity on phenol-formaldehyde resin cure

    Science.gov (United States)

    X.-M. Wang; B. Riedl; A.W. Christiansen; R.L. Geimer

    1994-01-01

    Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31...

  3. Differential scanning calorimetry investigation on vinyl ester resin curing process for polymer nanocomposite fabrication.

    Science.gov (United States)

    Guo, Zhanhu; Ng, Ho Wai; Yee, Gary L; Hahn, H Thomas

    2009-05-01

    Two different ceramic (cerium oxide and titanium oxide) nanoparticles were introduced into vinyl ester resin for nanocomposite fabrication. The curing process of the vinyl ester resin was investigated by a differential scanning calorimetery (DSC). The incorporation of nanoparticles in the resin affects the curing process due to the physicochemical interaction between the nanoparticles and the polymer matrix. The particle loading has a significant effect on the initial and peak curing temperatures, reaction heat and curing extent. The fully cured vinyl ester resin nanocomposites reinforced with cerium oxide nanoparticles were fabricated after a 24-hour room temperature curing and a one-hour postcuring at 85 degrees C. Particle functionalization favors the composite fabrication with a higher curing extent after room-temperature curing as compared to the as-received nanoparticle filled vinyl ester resin nanocomposites. The nanofiller materials were observed to significantly affect the curing process. In comparison to cerium oxide nanoparticles, titanium oxide nanoparticles prohibit the curing process with a much higher initiating curing temperatures. The fully cured nanocomposites reinforced with titanium oxide nanoparticles were fabricated by one-hour postcuring at 85 degrees C.

  4. Thermodynamic characterization of lithium monosilicide (LiSi) by means of calorimetry and DFT-calculations

    Energy Technology Data Exchange (ETDEWEB)

    Taubert, Franziska; Seidel, Juergen; Huettl, Regina; Mertens, Florian [TU Bergakademie Freiberg (Germany). Inst. of Physical Chemistry; Schwalbe, Sebastian; Gruber, Thomas; Kortus, Jens [TU Bergakademie Freiberg (Germany). Inst. of Theoretical Chemistry; Janot, Raphael [Univ. de Picardie Jules Verne UMR 7314 CNRS, Amiens (France). Lab. de Reactivity et Chimie des Solides; Bobnar, Matej [Max-Planck-Institute for Chemical Physics of Solids, Dresden (Germany); Gumeniuk, Roman [TU Bergakademie Freiberg (Germany). Inst. of Experimental Physics

    2017-11-15

    In this work we summarize a symbiotic approach to combine experimental and theoretical investigations for the derivation of high quality thermodynamic data for the description of potential lithium ion battery materials. The methodology of this concept was demonstrated in detail by exploring and describing the properties of the lithium monosilicide phase LiSi. The procedures were also applied in a series of investigations to all major Li{sub x}Si{sub y}-phases which will be reviewed briefly. Regarding the LiSi phase, the measured and calculated isobaric heat capacity, which may enable further thermodynamic investigations (e.g. with CALPHAD method) of the phase diagram of the Li-Si-system is presented. The heat capacity of the stable phase LiSi was measured as a function of temperature in a range from (2 to 673) K and compared with corresponding ab-initio and molecular dynamic calculations resulting in values for absolute entropies. The heat of formation of the system was determined in an unconventional manner via hydrogenation experiments.

  5. An Integrated-Circuit Temperature Sensor for Calorimetry and Differential Temperature Measurement

    Science.gov (United States)

    Muyskens, Mark

    1997-07-01

    Our application of an integrated-circuit (IC) temperature sensor which is easy-to-use, inexpensive, rugged, easily computer-interfacable and has good precision is described. The design, based on the National Semiconductor LM35 IC chip, avoids some of the difficulties associated with conventional sensors (thermocouples, thermistors, and platinum resistance thermometers) and a previously described IC sensor. The sensor can be used with a variety of data-acquisition systems. Applications range from general chemistry to physical chemistry, particularly where computer interfaced, digital temperature measurement is desired. Included is a detailed description of our current design with suggestions for improvement and a performance evaluation of the precision in differential measurement and the time constant for responding to temperature change.

  6. Hydrolysis of waste polyethylene terephthalate and characterization of products by differential scanning calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Gueclue, Gamze; Yalcinyuva, Tuncer; Oezguemues, Saadet; Orbay, Murat

    2003-09-04

    Neutral hydrolysis of waste polyethylene terephthalate (PET) has been carried out with different amounts of water and different catalysts, in the presence of xylene. The organic solvent made it possible to employ very little amounts of water, lower temperatures and pressures and providing concentrated ethylene glycol (EG) solutions in contrast with previous methods, yielding intermediates suitable for PET preparation. These intermediates were characterized by FTIR spectroscopy, acid value (AV), hydroxyl value (HV), viscosity average molecular weight determinations as well as by DSC. Multiple heating/cooling runs in DSC apparatus were carried out and a deconvolution procedure was applied using Haarhoff-Van der Linde (HVL) function to verify the presence of the same components and also to compare polymerization tendency of these various hydrolysis products.

  7. Determination of melting point of vegetable oils and fats by differential scanning calorimetry (DSC technique.

    Directory of Open Access Journals (Sweden)

    Nassu, Renata Tieko

    1999-02-01

    Full Text Available Melting point of fats is used to characterize oils and fats and is related to their physical properties, such as hardness and thermal behaviour. The present work shows the utilization of DSC technique on the determination of melting point of fats. In a comparison with softening point (AOCS method Cc 3-25, DSC values were higher than those obtained by AOCS method. It has occurred due to the fact that values obtained by DSC technique were taken when the fat had melted completely. DSC was also useful for determining melting point of liquid oils, such as soybean and cottonseed ones.

    El punto de fusión de grasas es usado para caracterizar aceites y grasas, y está relacionado con sus propiedades físicas, tales como dureza y comportamiento térmico. El presente trabajo muestra la utilización de la técnica de Calorimetría Diferencial de Barrido (DSC en la determinación del punto de fusión de grasas. En comparación con el punto de ablandamiento (AOCS método Cc 3-25, los valores de DSC fueron más altos que los obtenidos por los métodos de AOCS. Esto ha ocurrido debido al hecho que los valores obtenidos por la técnica de DSC fueron tomados cuando la grasa había fundido completamente. DSC fue también útil para determinar puntos de fusión de aceites líquidos, tales como los de soya y algodón.

  8. THE HEAT CAPACITY OF FLUORINATED PROPANE AND BUTANE DERIVATIVES BY DIFFERENTIAL SCANNING CALORIMETRY

    Science.gov (United States)

    The paper gives results of the measurement (to 3% accuracy) of the constant-pressure liquid-phase heat capacities of 21 hydrogen-containing fluorinated propane and butane derivatives and one fluorinated ether (CF3OCF2H) with boiling points ranging from -34.6 to 76.7 C, using diff...

  9. Precision Tracking and Electromagnetic Calorimetry Towards a Measurement of the Pion Polarisabilities at COMPASS

    CERN Document Server

    Dinkelbach, Anna-Maria Elisabeth

    2010-01-01

    In 2004 the COMPASS experiment at CERN SPS measured soft reactions with a beam of negatively charged pions on various nuclear targets. For this measurement, a silicon micro-strip telescope was installed in the target region. For the first time 5 silicon detector stations were operated simultaneously in the COMPASS experiment. A novel method of time calibration, with a clustering algorithm accordingly adapted, and refined alignment corrections were implemented in the analysis software. The spatial resolution of a silicon detector was determined to be 5 – 14 μm and the time resolution 2 – 3 ns. Combining the time information of all stations, a track time resolution of 530 ps from the silicon telescope could be reached. One of the key points of this experiment was the observation of Primakoff events, namely pions scattering off quasi-real photons in the Coulomb field of a heavy nucleus. The production of real photons corresponds to pion Compton scattering in inverse kinematics which is sensitive to the pion...

  10. STUDY OF SODIUM, POTASSIUM, AND CALCIUM SALTS INFLUENCE ON PROTEIN STABILITY BY DIFFERENTIAL SCANNING CALORIMETRY

    Directory of Open Access Journals (Sweden)

    E. K. Tunieva

    2016-01-01

    Full Text Available Abstract Study of protein stability depending on the various technological factors allows to directionally adjust the physicochemical properties of raw meat and the quality of finished meat products. The paper investigates the possibility of using the DSC to study the influence of monovalent and divalent salts on protein thermal stability. In order to determine the effect of sodium chloride and its substitutes, potassium and calcium salts, on the thermal stability of proteins, the studies were carried out with grinded pork longissimus muscle samples salted with sodium chloride at level of 2.0% and with salt compositions containing reduced by 50% level of sodium chloride (a mixture of sodium and potassium chlorides; a mixture of sodium, potassium, and calcium chlorides using the differential scanning calorimeter DSC Q 2000 in the temperature range of 5 °C to 100 °C and the temperature change rate of 1 K/min. It was found that the addition of potassium chloride instead of 50% of sodium chloride had no significant effect on actin and myosin resistance to thermal denaturation. Meat salting using the mixture of sodium, potassium, and calcium chlorides resulted in decrease of myofibrillar proteins stability indicating the destabilizing effect of calcium on actin and myosin. A negative correlation between the magnitude of the ionic strength and the temperature of myosin and actin denaturation has been found. The correlation coefficients were minus 0.99 and minus 0.95 for myosin and actin respectively. Reduction of denaturation temperature for myofibrillar proteins in the presence of calcium chloride opens perspectives to study the possibility of heat treatment at lower temperatures for meat products with reduced sodium content.

  11. Thermalization calorimetry: A simple method for investigating glass transition and crystallization of supercooled liquids

    DEFF Research Database (Denmark)

    Jakobsen, Bo; Sanz, Alejandro; Niss, Kristine

    2016-01-01

    We present a simple method for fast and cheap thermal analysis on supercooled glass-forming liquids. This “Thermalization Calorimetry” technique is based on monitoring the temperature and its rate of change during heating or cooling of a sample for which the thermal power input comes from heat...... conduction through an insulating material, i.e., is proportional to the temperature difference between sample and surroundings. The monitored signal reflects the sample’s specific heat and is sensitive to exo- and endothermic processes. The technique is useful for studying supercooled liquids...... and their crystallization, e.g., for locating the glass transition and melting point(s), as well as for investigating the stability against crystallization and estimating the relative change in specific heat between the solid and liquid phases at the glass transition...

  12. MORTAR INCORPORATING SUPPLEMENTARY CEMENTITIOUS MATERIALS: STRENGTH, ISOTHERMAL CALORIMETRY AND ACIDS ATTACK

    Directory of Open Access Journals (Sweden)

    Y. Senhadji

    2016-05-01

    Full Text Available Supplementary cementitious materials (SCMs prove to be effective to meet most of the requirements of durable concrete and leads to a significant reduction in CO2 emissions. This research studies the effect different SCMs (natural pozzolan (PN/ limestone fine (FC at various remplacement levels on the physical and mechano-chemical resistance of blended mortar. The paper primarily deals with the characteristics of these materials, including heat of hydration, strength and effects of aggressive chemical environments (using sulphuric acid and nitric acid. Over 6 mixes were made and compared to the control mix. Tests were conducted at different ages up to 360 days. The experimental results in general showed that Algerian mineral admixtures (PN/FC were less vulnerable to nitric and sulphuric acid attack and improved the properties of mortars, but at different rates depending on the quantity of binder.

  13. Glass-transition temperature gradient in nanocomposites: evidence from nuclear magnetic resonance and differential scanning calorimetry.

    Science.gov (United States)

    Papon, Aurélie; Montes, Hélène; Hanafi, Mohamed; Lequeux, François; Guy, Laurent; Saalwächter, Kay

    2012-02-10

    The slowing-down of the dynamics of a polymer chain near a surface has been observed for many years now. Here we show that the behavior of model nanocomposites can be quantitatively described with a gradient of glass-transition temperature. We describe with a single parameter-the range of this gradient-the temperature and solvent effect on the spin relaxation dynamics. Moreover, this parameter allows a quantitative description of the nanocomposite calorimetric response from the one of the bulk polymer.

  14. Combined Differential scanning calorimetry, Raman and Brillouin spectroscopies: A multiscale approach for materials investigation.

    Science.gov (United States)

    Veber, A; Cicconi, M R; Reinfelder, H; de Ligny, D

    2018-01-15

    A new experimental setup combining DSC, Raman and Brillouin spectroscopies was developed. In order to estimate its accuracy and stability a study of silicon and the alpha-beta quartz phase transition were performed. The data obtained demonstrated good agreement with previous studies using these three different techniques. For quartz, the temperature behavior of its 147 cm-1 Raman mode was studied in detail. Using a two-phonon coupling treatment of the Raman band, we show for the first time that its behavior can be well described by Landau theory of first-order phase transitions. The combined DSC-Raman-Brillouin technique is a powerful tool for material science capable of studying thermal, structural and elastic properties simultaneously. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. A New Calorimetry Design for Assessing Proposed Technologies in Low Energy Power Production

    Science.gov (United States)

    2012-12-01

    heat Where Mbb, Hbb the rate and the enthalpy of the heat source, Mcw ,Hcw the rate and the enthalpy of cold water, Mout , Hout the rate and the...So the enthalpy Hbb of the heat source could be calculated Furthermore, it is important to mention that the “heat input” in the sketch could be...device. That is, the first term on the right side of the equation dMbb Hbb can be treated as a lumped. This will still provide the desired result: a

  16. Application of calorimetry on a chip to high-pressure materials.

    Science.gov (United States)

    Navrotsky, Alexandra; Dorogova, Maria; Hellman, Frances; Cooke, David W; Zink, Barry L; Lesher, Charles E; Boerio-Goates, Juliana; Woodfield, Brian F; Lang, Brian

    2007-05-29

    Silicon micromachined calorimeters ("calorimeter on a chip") are used to measure heat capacities and phase transition enthalpies for thin film, single crystal, and powder samples (5-500 mug). The technology is thus compatible with the small samples produced in multianvil and large diamond anvil cells. Techniques for handling small samples and attaching them to the calorimetric devices have been developed. Initial data illustrate application to CoO and to Fe(2)SiO(4) olivine and spinel, a quenched high pressure phase metastable at ambient conditions. The calorimetric entropy of the olivine-spinel transition in Fe(2)SiO(4) (-16 +/- 5 J/mol.K) is in good agreement with that calculated from phase equilibrium data (-14 +/- 3 J/mol.K). A magnetic transition in iron silicate spinel, detected previously by Mossbauer spectroscopy, is seen in the calorimetric signal.

  17. Isoperibolic Titration Calorimetry as a Tool for the Prediction of Thermodynamic Properties of Cyclodextrins

    Directory of Open Access Journals (Sweden)

    Liliana Giraldo

    2008-10-01

    Full Text Available The interaction of guest molecules ranging from pentan-1-ol to octan-1-ol with α-cyclodextrin (α-CD in water of has been studied calorimetrically at 283.15, 288.15, 293.15, 298.15 and 308.15 K with an isoperibolic titration calorimeter designed in our laboratory. The calorimetric method employed allows the determination of the thermodynamic parameters characterizing the binding process, ΔG°m, ΔH°m, ΔS°mand ΔCp°, namely free energy, enthalpy, and calorific capacity. These results show that in the temperature range investigated, the entropy change increased with chain length. This is in line with what is expected for a hydrophobic dehydration process. However, that effect is not expected to lead to the more pronounced negative CH2-increment observed for nc > 5 or 6. As for many other ligand binding processes, we can observe a significant enthalpy - entropy compensation for this system, both with respect to temperature and structure.

  18. Detection of conformational changes in immunoglobulin G using isothermal titration calorimetry with low molecular weight probes

    NARCIS (Netherlands)

    Rispens, T.; Lakemond, C.M.M.; Derksen, N.I.L.; Aalberse, R.C.

    2008-01-01

    Proteins for therapeutic use may contain small amounts of partially misfolded monomeric precursors to postproduction aggregation. To detect these misfolded proteins in the presence of an excess of properly folded protein, fluorescent probes such as 8-anilino-1-naphthalene sulfonate (ANS) are

  19. TEST BEAM COORDINATION: The 2004 Test Beam Calorimetry set-up in H8

    CERN Multimedia

    Aleksa, M; Di Girolamo, B; Ferrari, C; Giugni, D; Santoni, C; Wingerter, I

    A new table has been designed, built and finally mounted to position the LAr cryostat in front of the Tilecal modules. The new table has been connected to the existing Tilecal table to be able to move the full set-up along eta values between 0 and 1.2. The table has been conceived by D. Giugni (INFN Milano and now CERN PH) and modeled by G. Braga (INFN Milano) in spring-summer 2003. The realization of the table has been done by an Italian firm (MatecImpianti, Fenegrò, Como) under the supervision of S. Coelli (INFN Milano) starting August 2003. Figure 1 shows the table assembled at the firm (left). Figure 1: The Tilecal-LAr table: in Fenegro (left) and at CERN (right). In November 2003 the table has been delivered to CERN and put in temporary storage to be assembled after the preparation of the Tilecal zone. In February 2004 two technicians from the firm and the team of technician coordinated by C. Ferrari (CERN AB/ATB), assembled, tested and commissioned the table under the supervision of S. Coelli...

  20. Upgrade Plans for ATLAS Forward Calorimetry for the HL-LHC

    CERN Document Server

    Turner, J

    2012-01-01

    Even though data-taking has just started with the LHC, plans are being developed to operate the machine and its detectors at up to 10 times the original design luminosity. This has a major impact on the Forward Calorimeter (FCal), which is exposed to some of the highest radiation rates in ATLAS. The FCal detector and its associated components were designed for operation at the maximum LHC luminosity of \\(\\text{10}^{\\text{34}} \\text{ cm}^{-2}\\text{s}^{-1}\\). However at the higher luminosities projected for the HL-LHC, operation of the FCal may be compromised. Beam heating in the FCal could lead to the formation of argon bubbles in the detector, the ionization rate will result in space charge effects that will reduce the signal and the current draw will result in a voltage drop across the HV current limiting resistors. Two possible solutions are being considered to maintain FCal operation at HL-LHC. One is a complete replacement of the FCal system. A replacement FCal would have a similar design to the current c...

  1. Upgrade plans for ATLAS Forward Calorimetry for the HL-LHC

    CERN Document Server

    Randrianarivony, K; The ATLAS collaboration

    2011-01-01

    Even though data taking has just started with the LHC, plans are being developed to operate the machine and its detectors at up to 10 times the original design luminosity. This has an impact on many components of the ATLAS detector, particularly the Forward calorimeter, which is exposed to some of the highest radiation rates in ATLAS. The FCal detector and its associated components were designed for operation at the maximum LHC luminosity of 1034 cm2s-1. However at the higher luminosities (HL), which are projected for the HL-LHC, operation of the FCal will be compromised. Beam heating in the FCal which is located on a liquid argon filled cryostat could lead to the formation of argon bubbles in the detector, the ionization rate will result in space charge effects that will reduce the signal and the current draw will result in a voltage drop across the HV current limiting resistors. The space charge and ionization rates will result in the FCal becoming insensitive to particles at its inner edge and the insensit...

  2. Estimating the Energy Content of Wastewater Using Combustion Calorimetry and Different Drying Processes

    Directory of Open Access Journals (Sweden)

    Benjamin Korth

    2017-09-01

    Full Text Available The energy content of wastewater is routinely assessed by chemical oxygen demand (COD measurements that only provide an incomplete picture and the data fundament of other energy parameters remains scarce. The volumetric heat of combustion (ΔCH of raw wastewater from a municipal wastewater treatment plant (WWTP was assessed using oven drying method (ΔCHvol = −6.8 ± 4.3 kJ L−1, n = 20 and freeze drying method (ΔCHvol = −20.2 ± 9.7 kJ L−1, n = 6 illustrating the substantial loss during the oven drying approach. Normalizing ΔCH to COD of raw wastewater yielded −6.2 ± 3.5 kJ gCOD−1 for oven-dried samples (n = 14 and −13.0 ± 1.6 kJ gCOD−1 for freeze-dried samples (n = 3. A subsequent correlation analysis with further chemical wastewater parameters revealed a dependency of ΔCHvol on COD, total organic carbon (TOC, C:N ratio, and total sulfur content. To verify these correlations, wastewater of a second WWTP was sampled and analyzed. Only COD and TOC were in accordance with the data set from the first WWTP representing potential predictors for the chemical energy stored in wastewater for comparable WWTPs. Unfortunately, during the most practical method (oven drying, a certain loss of volatile compounds is inevitable so that the derived ΔCHvol systematically underestimates the total energetic potential of wastewater. Nevertheless, this work expands the, so far, little data fundament on the energy resource wastewater and implies the requirement for further long-term studies on different sites and different wastewater types with a highly standardized sample treatment protocol.

  3. High precision calorimetry to determine the enthalpy of combustion of methane

    Energy Technology Data Exchange (ETDEWEB)

    Dale, Andrew; Lythall, Christopher; Aucott, John; Sayer, Courtnay [Office of Gas and Electricity Markets, Technical Directorate, 3 Tigers Road, South Wigston, LE18 4UX Leicester (United Kingdom)

    2002-01-31

    The enthalpy of combustion of methane is the most important property used in the determination of the calorific value of natural gas. Only two sets of values with high accuracy and precision and measured under appropriate conditions have been published since it was first determined in 1848. These studies were done by Rossini, at the National Bureau of Standards in the USA in 1931, and Pittam and Pilcher, at the University of Manchester in 1972. This report details the design and operation of a high precision constant-pressure gas burning calorimeter, based on the design of those used in the previous studies, to measure the superior enthalpy of combustion of ultra-high purity methane at 25C.The use of modern equipment and automatic data collection leads to a value, traceable to national standards, of 890.61kJmol{sup -1} with a combined standard uncertainty of 0.21kJmol{sup -1}. This is in full accord with the value of 890.63kJmol{sup -1} calculated from the average of Rossini's and Pittam and Pilcher's work (with a random uncertainty based on 1 S.D. of 0.53kJmol{sup -1})

  4. A Layer Correlation Technique for ATLAS Calorimetry Calibration at the 2004 ATLAS Combined Beam Test

    CERN Document Server

    Carli, T; Spanò, F; Speckmayer, P

    2008-01-01

    A method for calibrating the response of a segmented calorimeter to hadrons is developed. The ansatz is that information on longitudinal shower fluctuations gained from a principal component analysis of the layer energy depositions can improve energy resolution by correcting for hadronic invisible energy and dead material losses: projections along the eigenvectors of the correlation matrix are used as input for the calibration. The technique is used to reconstruct the energy of pions impinging on the ATLAS calorimeters during the 2004 Barrel Combined Beam Test at the CERN H8 area. Simulated Monte Carlo events are used to derive corrections for invisible energy lost in nuclear reactions and in dead material in front and in between the calorimeters. For pion beams with energies between 20 and 180 GeV, the particle energy is reconstructed within 3% and the resolution is improved by about 20%.

  5. VO2sim 0.1: Using Simulation to Understand Measurement Error in Indirect Calorimetry

    Science.gov (United States)

    2015-08-01

    Med Sport . 2004;7(1):11– 22. Gefen A. Biomechanical analysis of fatigue-related foot injury mechanisms in athletes and recruits during intensive... Sport . 2013;84(2):223–231. Duffield R, Dawson B, Pinnington H, Wong P. Accuracy and reliability of a Cosmed K4b2 portable gas analysis system. J Sci...Mair SD, Seaber AV, Glisson RR, Garrett WE. The role of fatigue in susceptibility to acute muscle strain injury. Am J Sports Med. 1996;24(2):137–143

  6. Pyrolysis kinetics and combustion of thin wood using advanced cone calorimetry test method

    Science.gov (United States)

    Mark A. Dietenberger

    2011-01-01

    Mechanistic pyrolysis kinetics analysis of extractives, holocellulose, and lignin in solid wood over entire heating regime was possible using specialized cone calorimeter test and new mathematical analysis tools. Added hardware components include: modified sample holder for thin specimen with tiny thermocouples, methane ring burner with stainless steel mesh above cone...

  7. Energy metabolism of overweight women before, during and after weight reduction, assessed by indirect calorimetry

    NARCIS (Netherlands)

    Groot, de C.P.G.M.

    1988-01-01

    Previous studies had suggested that periods of low energy intake evoke compensatory adaptations in energy metabolism, which retard weight loss, and promote weight regain when energy intake returns to normal. The aim of this thesis was to investigate whether a slimming (low-energy) diet based on

  8. Characterization of pH-sensitive hydrogels by conductimetry and calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Sheppard, N.F. Jr.; Chen, Jey-Hsin; Lawson, H.C.; Salehi-Had, S.; Tucker, R.C. [John Hopkins Univ., Baltimore, MA (United States)

    1993-12-31

    The total and freezing water contents, and electrical conductivity of pH-sensitive hydrogels formed from poly(hydroxyethyl methacrylate - co - dimethylaminoethyl methacrylate) were measured as a function of copolymer composition and pH. For an 80/20 HEMA/DMAEMA gel (mole ratio), the water content increases from 37% at pH 10 of the bathing solution value at pH 10 to 90% at low pH. The difference between total and freezing water content in the gels is approximately 25%, consistent with values reported in the literature. An examination of the results in the context of the Yasuda free- volume model suggests that freezing water content, rather than total water content, may be suitable for modelling of hydrogel conductivity.

  9. Precision tracking and electromagnetic calorimetry towards a measurement of the pion polarisabilities at COMPASS

    Energy Technology Data Exchange (ETDEWEB)

    Dinkelbach, Anna-Maria Elisabeth

    2010-07-20

    In 2004 the COMPASS experiment at CERN SPS measured soft reactions with a beam of negatively charged pions on various nuclear targets. For this measurement, a silicon micro-strip telescope was installed in the target region. For the first time 5 silicon detector stations were operated simultaneously in the COMPASS experiment. A novel method of time calibration, with a clustering algorithm accordingly adapted, and refined alignment corrections were implemented in the analysis software. The spatial resolution of a silicon detector was determined to be 5 - 14 {mu}m and the time resolution 2 - 3 ns. Combining the time information of all stations, a track time resolution of 530 ps from the silicon telescope could be reached. One of the key points of this experiment was the observation of Primakoff events, namely pions scattering off quasi-real photons in the Coulomb field of a heavy nucleus. The production of real photons corresponds to pion Compton scattering in inverse kinematics which is sensitive to the pion polarisabilities {alpha}{sub {pi}} and {beta}{sub {pi}}. Key ingredient for such measurements is a precise knowledge of the performance of the electromagnetic calorimeter. This includes a study of the instabilities of calorimeter cells and an improved reconstruction algorithm. A data-driven shower model was developed, which was used for a timedependent recalibration of the calorimeter. A new cluster refitting method was used to recover position and energy of clusters containing passive or saturated cells and detects double-hit clusters. The latter are important, as the main background to the Primakoff Compton events stems from neutral pions misinterpreted as single-photon hits. The physics analysis comprised the selection of Primakoff events and the necessary steps to obtain the pionic polarisabilities. The measurement was limited by systematic effects of the apparatus also determined within this thesis. (orig.)

  10. Heat capacity changes associated with guanine quadruplex formation: an isothermal titration calorimetry study.

    Science.gov (United States)

    Majhi, Pinaki R; Qi, Jianying; Tang, Chung-Fei; Shafer, Richard H

    2008-04-01

    This study addresses the temperature dependence of the enthalpy of formation for several unimolecular quadruplexes in the presence of excess monovalent salt. We examined a series of biologically significant guanine-rich DNA sequences: thrombin binding aptamer (TBA) (d(G(2)T(2)G(2)TGTG(2)T(2)G(2)), PS2.M, a catalytically active aptamer (d(GTG(3)TAG(3)CG(3)T(2)G(2))), and the human telomere repeat (HT) (d(AG(3)(T(2)AG(3))(3))). Using CD spectra and UV melting, we confirmed the presence of quadruplex structures and established the temperature range in which quadruplex conformation is stable. We then performed ITC experiments, adding DNA to a solution containing excess NaCl or KCl. In this approach, only several additions are made, and only the enthalpy of quadruplex formation is measured. This measurement was repeated at different temperatures to determine the temperature dependence of the enthalpy change accompanying quadruplex formation. To control for the effect of nonspecific salt interactions during DNA folding, we repeated the experiment by replacing the quadruplex-forming sequences with a similar but nonfolding sequence. Dilution enthalpies were also subtracted to obtain the final enthalpy value involving only the quadruplex folding process. For all sequences studied, quadruplex formation was exothermic but with an increasing magnitude with increasing temperature. These results are discussed in terms of the change in heat capacity associated with quadruplex formation.

  11. Optimizing isothermal titration calorimetry protocols for the study of 1:1 binding: Keeping it simple.

    Science.gov (United States)

    Tellinghuisen, Joel

    2016-05-01

    Successful ITC experiments require conversion of cell reagent (titrand M) to product and production or consumption of heat. These conditions are quantified for 1:1 binding, M+X ⇔ MX. Nonlinear least squares is used in error-propagation mode to predict the precisions with which the key quantities - binding constant K, reaction enthalpy ΔH°, and stoichiometry number n - can be estimated over a wide range of the dimensionless quantity that governs isotherm shape, c=K[M]0. The measurement precision σq is estimated from analysis of water-water blanks. When the product conversion exceeds 90%, the parameter relative standard errors are proportional to σq/qtot, where the total heat qtot ≈ ΔH° [M]0V0. Specifically, σK/K×qtot/σq ≈ 25 for c=10(-3)-10, ≈ 11 c(1/3) for c=10-10(4). For c>1, n and ΔH° are more precise than K; this holds also at smaller c for the product n×ΔH° and for ΔH° when n can be held fixed. Use of as few as 10 titrant injections can outperform the customary 20-40 while also improving productivity. These principles are illustrated in experiment design using the program ITC-PLANNER15. Simple quantitative guidelines replace the "c rules" that have dominated the literature for decades. Copyright © 2015 Elsevier B.V. All rights reserved.

  12. Upgrade Plans for ATLAS Forward Calorimetry for the HL-LHC

    Science.gov (United States)

    Turner, J.; ATLAS Liquid Argon Calorimeter Group

    Even though the LHC is still in an early phase of operation, plans are being developed to operate the machine and its detectors at up to 10 times the original design luminosity. This has a major impact on the Forward Calorimeter (FCal), which is exposed to some of the highest radiation rates in ATLAS. The FCal detector and its associated components were designed for operation at the maximum LHC luminosity of 1034 cm-2s-1. However at the higher luminosities projected for the HL-LHC, operation of the FCal may be compromised. Beam heating in the FCal could lead to the formation of argon bubbles in the detector, the ionization rate will result in space charge effects that will reduce the signal and the current draw will result in a voltage drop across the HV current limiting resistors. Two possible solutions are being considered to maintain FCal operation at HL-LHC. One is a complete replacement of the FCal system. A replacement FCal would have a similar design to the current calorimeter except for the addition of cooling loops, lower value HV protection resistors and the use of smaller ionization gaps, as small as 100 microns in the first compartment. The second solution is the installation of a small warm calorimeter, referred to as the Mini-FCal, to be placed in front of the FCal. This addition would reduce the ionization load in the first FCal compartment, which would keep a larger region of the FCal active and reduce the heat load to an acceptable level. The current concept for the Mini-FCal is a standard parallel plate calorimeter with copper absorbers and diamond sensors, which were chosen for their inherent radiation resistance. It is anticipated that neutrons will be the major cause of damage to the diamond sensors and the integrated flux of neutrons in the Mini-FCal after 3000 fb-1 at the HL-LHC will be up to 2 x 1017 neutrons/cm2. Recent irradiation tests carried out by members of the ATLAS Liquid Argon group show that these sensors can still operate after irradiation up to these levels although with a large reduction in signal.

  13. Thermalization calorimetry: A simple method for investigating glass transition and crystallization of supercooled liquids

    Directory of Open Access Journals (Sweden)

    Bo Jakobsen

    2016-05-01

    Full Text Available We present a simple method for fast and cheap thermal analysis on supercooled glass-forming liquids. This “Thermalization Calorimetry” technique is based on monitoring the temperature and its rate of change during heating or cooling of a sample for which the thermal power input comes from heat conduction through an insulating material, i.e., is proportional to the temperature difference between sample and surroundings. The monitored signal reflects the sample’s specific heat and is sensitive to exo- and endothermic processes. The technique is useful for studying supercooled liquids and their crystallization, e.g., for locating the glass transition and melting point(s, as well as for investigating the stability against crystallization and estimating the relative change in specific heat between the solid and liquid phases at the glass transition.

  14. The Relation between Immersion Calorimetry and the Parameters of the Water Adsorption Isotherm on Active Carbons

    OpenAIRE

    Kraehenbuehl, Francis; Quellet, Christian; Schmitter, Beat; Stoeckli, Fritz

    2007-01-01

    It is shown that for active carbons with a single type of hydrophilic adsorption sites, the enthalpy of immersion into water is related to the number of sites, a0, and to a parameter, c, both of which appear in the Dubinin–Serpinskii equation for the water adsorption isotherm. The correlation was established on the basis of data for 13 different active carbons whose sites were either acidic or of the carbonyl type. It follows that the adsorption branch of the water isotherm can be calculated ...

  15. Lipid domains in the ram sperm plasma membrane demonstrated by differential scanning calorimetry.

    OpenAIRE

    Wolf, D. E.; Maynard, V M; McKinnon, C A; Melchior, D L

    1990-01-01

    Mammalian sperm plasma membranes, in contrast to those of mammalian somatic cells, exhibit a significant fraction of lipid that does not diffuse laterally in the plane of the membrane. This nondiffusing fraction results from lipid-lipid interactions. Similar nondiffusing fractions are found in mixed-lipid model systems that contain coexistent gel and fluid domains. These results suggest that the sperm plasma membrane may also exhibit lateral phase segregations of lipids and may contain signif...

  16. Upgrade Plans for ATLAS Forward Calorimetry for the HL-LHC

    CERN Document Server

    Krieger, P; The ATLAS collaboration

    2013-01-01

    The upgrade of the LHC Collider foresees increased instantaneous luminosity 3-7 times the original design value of 10$^{34}$ cm$^{-2}$ s$^{-1}$. The increased particle flux at this high luminosity phase of the LHC (HL-LHC) will have an impact on many sub-systems of the ATLAS detector. In particular, in the LAr forward calorimeter (FCal), which was designed for operation at LHC luminosities, the associated increase in the ionization load at HL-LHC luminosities poses a number of problems that can degrade its performance, related to beam heating, space charge effects in the LAr gaps and HV drop due to increased current draws over the HV current-limiting resistors. One solution to these problems, which would require the opening of both ATLAS endcap cryostats, is the construction and installation of a new FCal, with cooling loops, narrower LAr gaps, and lower value protection resistors. The signal performance of the current FCal and of a possible narrow-gap FCal has been measured in a dedicated test-beam campaign ...

  17. Recent advances and potential applications of modulated differential scanning calorimetry (mDSC) in drug development

    DEFF Research Database (Denmark)

    Knopp, Matthias Manne; Löbmann, Korbinian; Elder, David P.

    2016-01-01

    of these applications. It is aimed to serve as a broad introduction to newcomers, and also as a valuable reference for those already practising in the field. Complex mDSC was introduced more than two decades ago and has been an important tool for the quantification of amorphous materials and development of freeze......-dried formulations. However, as discussed in the present review, a number of other potential applications could also be relevant for the pharmaceutical scientist......., conventional DSC has shortcomings with respect to weak transitions and overlapping events, which could be solved by the use of the more sophisticated modulated DSC (mDSC). mDSC has multiple potential applications within the pharmaceutical field and the present review provides an up-to-date overview...

  18. Fecal energy losses in enterally fed intensive care patients: An explorative study using bomb calorimetry

    NARCIS (Netherlands)

    Strack van Schijndel, R.J.M.; Wierdsma, N.J.; van Heijningen, E.M.B.; Weijs, P.J.M.; de Groot, S.D.W.; Girbes, A.R.J.

    2006-01-01

    Background & Aims: Early enteral nutrition and tailored supply of nutrients have become standard in most of the intensive care units (ICU). So far little attention has been given to losses of energy in the stools. The purpose of this explorative study was to evaluate the energy losses of patients

  19. Development of Silicon Photomultipliers and their Applications to GlueX Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Smith, Elton S. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)

    2016-07-01

    The GlueX experiment is a photoproduction experiment in Hall D at Jefferson Lab that is being commissioned for use with the new 12 GeV accelerator. The purpose of the experiment is to search for Hybrid mesons, which are mesons with quark and gluon degrees of freedom. The barrel calorimeter of GlueX is instrumented with 4000 large-area (1.2 x1.2 cm2) silicon photomultipliers (SiPMs). These photon sensors have properties similar to vacuum photomultipliers, but are unaffected by high magnetic fields. In our experiment they operate in magnetic fields exceeding 1T. After extensive tests with a variety of sensors, we chose the S12045(X) custom SiPM arrays manufactured by Hamamatsu Corporation, also known as multi-pixel photon counters (MPPCs). We will give an overview of this new technology as well as the experience gained during two commissioning periods with beam.

  20. Differential Scanning Calorimetry Investigations on Polyvinylidene Fluoride - Fe3O4 Nanocomposites

    Science.gov (United States)

    Salinas, Samantha; Jones, Robert; Chipara, Dorina M.; Chipara, Mircea

    2015-03-01

    Nanocomposites of polyvinylidene fluoride (PVDF)-magnetite (Fe3O4) with various weight fractions of nanofiller (0%, 0.2 %, 0.6 %, 1.2%, 2.4 %, 5.8 %, 12 %, 23 %, and 30 %) have been obtained via melt mixing by loading PVDF with Fe3O4 particles (average size 75 nm from Nanostructured & Amorphous Materials, Inc). Thermal stability of PVDF-Fe3O4 has been investigated by TGA in nitrogen. The increase of the thermal stability of PVDF due to the loading with Fe3O4 was quantified by the shift of the temperature at which the (mass) degradation rate is maximum as a function of Fe3O4 content. The effect of the nanofiller on the crystallization of PVDF was investigated by isothermal DSC (TA Instruments, Q500). Non isothermal DSC tests, (at various heating rates ranging from 1 to 25 °C/min) have been used to locate the glass, crystallization, and melting temperatures. The dependence of the glass, crystallization, and melting temperatures on the concentration of nanoparticles is reported and analyzed in detail. The data are critically analyzed within the classical Avrami theory.

  1. Differential Scanning Calorimetry (DSC and Thermogravimetric Analysis (TGA of Wood polymer nanocomposites

    Directory of Open Access Journals (Sweden)

    Rahman Md. Rezaur

    2017-01-01

    Full Text Available This study evaluates the thermal property of clay dispersed Styrene-co-Glycidal Methacrylate impregnated wood polymer nanocomposite (WPNC. The WPNC was characterized by FTIR, TGA and DSC methods. FT-IR result showed that the absorbance of wave number at 1730 cm−1, increased for clay dispersed Styrene-co-Glycidyl Methacrylate wood polymer nanocomposite (ST-co-GMA-clay-WPNC. From TGA, ST-co-GMA-clay-WPNC showed better thermal stability at the temperature below 450oC. The final weights of ST-co-GMA-clay-WPNC and ST-Clay-WPNC, between 420 and 700oC, were significantly less than the raw wood. When the temperature was below 450oC, nanoclay-incorporated surface modified wood composites showed enhanced higher thermal properties compared with those without nanoclay. From DSC, the degradation enthalpy at around 360oC of ST-co-GMA-Clay-WPNC was the highest.

  2. Review of Nuclear Heating Measurement by Calorimetry in France and USA

    Science.gov (United States)

    Reynard-Carette, C.; Kohse, G.; Brun, J.; Carette, M.; Volte, A.; Lyoussi, A.

    2018-01-01

    This paper gives a short review of sensors dedicated to measuring nuclear heating rate inside fission reactors in France and USA and especially inside Material Testing Reactors. These sensors correspond to heat flow calorimeters composed of a single calorimetric cell or of two calorimetric cells at least with a reference cell to obtain a differential calorimeter. The aim of this paper is to present the common running principle of these sensors and their own special characteristics through their design, calibration methods, and in-pile measurement techniques, and to describe multi-sensor probes including calorimeters.

  3. A digital front-end and readout microsystem for calorimetry at LHC--The FERMI project

    Energy Technology Data Exchange (ETDEWEB)

    Dell' Acqua, A.; Hansen, M.; Lofstedt, B.; Vanuxem, J.P. (CERN, Geneva (Switzerland)); Svensson, C.; Yuan, J. (Univ. of Linkoeping (Sweden). Dept. of Physics and Measurement Technology); Hentzell, H. (Univ. of Linkoeping (Sweden). Center for Industrial Microelectronics and Materials Technology); Alippi, C.; Breveglieri, L.; Dadda, L.; Piuri, V.; Salice, F.; Sami, M.; Stefanelli, R. (Sezione INFN, Pavia, Milano (Italy). Dept. di Ellettronica); Cattaneo, P.; Fumagalli, G.; Goggi, V.G. (Univ. e Sezione INFN, Pavia (Italy). Dept. di Fisica Nucleare); Brigati, S.; Gatti, U.; Maloberti, F.; Torelli, G. (Univ. e Sezione INFN, Pavia (Italy). Dept. di Electronica); Carlson, P.; Fuglesang, C.; Kerek, A. (Manne Siegbahn Inst. of Physics, Stockholm (Sweden)); Appelquist, G.; Berglund, S.; Bohm, C.; Yamdagni, N. (Univ. of Stockholm (Sweden)); Sundblad, R. (SiCon AB, Linkoeping (Sweden))

    1993-08-01

    The authors present a digital solution to the front-end electronics for calorimetric detectors at future supercolliders based on high speed A/D converters, a fully programmable pipeline/digital filter chain and local intelligence. Questions of error correction, fault-tolerance and system redundancy are also considered. A system integration of a multichannel device in a multichip, Silicon-on-Silicon Microsystem hybrid will be used. This solution allows a new level of integration of complex analog and digital functions, with an excellent flexibility in mixing technologies for the different functional blocks. This type of VLSI multichip integration allows a high degree of programmability at both the function and the system level, and offers the possibility of customizing the microsystem with detector-specific functions.

  4. Energy requirements of lean and overweight women, assessed by indirect calorimetry

    NARCIS (Netherlands)

    Boer, de J.O.

    1985-01-01

    The prevalence of overweight in the developed world and the increased mortality and morbidity risk of overweight people stimulate research into the imbalance between energy intake and energy expenditure. Little information is available about the 24 hour energy expenditure and energy requirement of

  5. Radiation Hard Active Media R&D for CMS Hadron Endcap Calorimetry

    Science.gov (United States)

    Tiras, Emrah; CMS-HCAL Collaboration

    2015-04-01

    The High Luminosity LHC era imposes unprecedented radiation conditions on the CMS detectors targeting a factor of 5-10 higher than the LHC design luminosity. The CMS detectors will need to be upgraded in order to withstand these conditions yet maintain/improve the physics measurement capabilities. One of the upgrade options is reconstructing the CMS Endcap Calorimeters with a shashlik design electromagnetic section and replacing active media of the hadronic section with radiation-hard scintillation materials. In this context, we have studied various radiation-hard materials such as Polyethylene Naphthalate (PEN), Polyethylene Terephthalate (PET), HEM and quartz plates coated with various organic materials such as p-Terphenyl (pTp), Gallium doped Zinc Oxide (ZnO:Ga) and Anthracene. Here we discuss the related test beam activities, laboratory measurements and recent developments.

  6. Cerium doped heavy metal fluoride glasses, a possible alternative for electromagnetic calorimetry

    CERN Document Server

    Auffray, Etiennette; Dafinei, I; Fay, J; Lecoq, P; Mares, J A; Martini, M; Mazé, G; Meinardi, F; Moine, B; Nikl, M; Pédrini, C; Poulain, M; Schneegans, M; Tavernier, Stefaan; Vedda, A

    1996-01-01

    The article is an overview of the research activity performed in the framework of the Crystal Clear Collaboration to produce scintillating glasses. The manufacturing of heavy metal fluoride glasses doped with Ce3+ is discussed. The luminescence and scintillation characteristics as well as the radiation hardness properties are extensively studied in the case of Ce doped fluorohafnate , found to be the most convenient glass scintillator for high energy physics applications.

  7. The Curing Process of Epoxy/Amino-Functionalized MWCNTs: Calorimetry, Molecular Modelling, and Electron Microscopy

    Directory of Open Access Journals (Sweden)

    S. G. Prolongo

    2010-01-01

    Full Text Available Curing kinetic of an epoxy resin reinforced with amino-functionalized MWCNTs has been studied by DSC and the obtained results were explained through morphological studies carried out by SEM, TEM, FEG-SEM, and molecular simulation tools. The presence of MWCNTs in the curing reaction induces a retardation effect of curing reaction and a decrease of the reaction heat. Both are associated with the adsorption of curing agent molecules inside carbon nanotubes, which was proved through the application of electron microscopic techniques and molecular simulation tools. It has been also demonstrated that there is a chemical reaction between amine groups anchored to the nanotubes and oxirane rings of epoxy monomer, which improves the nanoreinforcement/matrix interfacial adhesion, appearing a chemical interphase. The glass transition temperature (Tg of epoxy matrix increases by the addition of MWCNTs due to the restriction of its mobility.

  8. Partitioning of late gestation energy expenditure in ewes using indirect calorimetry and a linear regression approach

    DEFF Research Database (Denmark)

    Kiani, Alishir; Chwalibog, André; Nielsen, Mette O

    2007-01-01

    Late gestation energy expenditure (EE(gest)) originates from energy expenditure (EE) of development of conceptus (EE(conceptus)) and EE of homeorhetic adaptation of metabolism (EE(homeorhetic)). Even though EE(gest) is relatively easy to quantify, its partitioning is problematic. In the present...

  9. Progress in LAr EndCap Calorimetry: News from the Hadronic EndCap Group.

    CERN Multimedia

    Oram, C.J.

    With module production and testing completed for the Hadronic EndCap calorimeter, the attention of the HEC group is heavily directed towards wheel assembly in building 180. Three of the four HEC wheels are now assembled and rotated, and work is progressing on assembling the final wheel. This year has been a busy year for the installation of components in the EndCap C cryostat: the signal feedthrough installation was completed April 22nd, the pre-sampler shortly thereafter and the Electro-Magnetic EndCap August 13th. This allowed the HEC group to start transferring the HEC wheels from the T6A storage cradle into the cryostat. The operation started in mid-September and has progressed, on or ahead of schedule, since then with the major milestones being: Insertion of 67 ton front HEC wheel October 3rd Insertion of 90 ton rear HEC wheel October 22nd. The wheel alignment has proved to be excellent, with the position of the centre of the front(rear) wheel with respect to the nominal position being displaced b...

  10. Water calorimetry with thermistor bridge operated in DC and AC mode: comparative results

    Energy Technology Data Exchange (ETDEWEB)

    Guerra, A.S.; Laitano, R.F.; Petrocchi, A. [Ist. Nazionale di Metrologia delle Radiazioni Ionizzanti, ENEA, Roma (Italy)

    1997-09-01

    An experimental study was carried out to find out the optimal conditions for measuring the output signal in a water calorimeter. To this end the thermistor bridge of the calorimeter was operated in AC and in DC mode, respectively. A comparative analysis of these two alternative methods was the made. In the AC mode measurement a lock-in amplifier based experimental assembly was used and compared to the more conventional system based on a high-sensitivty DC amplifier. The AC system resulted to be preferable as far as the short term and long term reproducibility is concerned. (orig.)

  11. Differential scanning calorimetry studies of Se85Te15–xPbx (x= 4, 6 ...

    Indian Academy of Sciences (India)

    The Hruby number (indicator of ease of glass forming and higher stability) is the highest for Se85Te9Pb6 glass while S factor (indicator of resistance to devitrification) is highest for Se85Te7Pb8 glass at all heating rates in our experiment. Further the highest resistance to devitrification has the highest value of structural ...

  12. Quantitative Assessment of Pore Blockage in Supported Catalysts: Comparing Differential Scanning Calorimetry and Physisorption

    NARCIS (Netherlands)

    Eggenhuisen, T.M.|info:eu-repo/dai/nl/313959498; Zecevic, J.|info:eu-repo/dai/nl/341386715; Talsma, H.|info:eu-repo/dai/nl/08138212X; de Jong, K.P.|info:eu-repo/dai/nl/06885580X; de Jongh, P.E.|info:eu-repo/dai/nl/186125372

    2012-01-01

    Mesoporous materials are commonly used as supports for a guest phase, such as catalytically active transition metal nanoparticles. N2 physisorption at 77 K is the standard technique to characterize mesoporosity; however, it is not always suitable to assess pore blockage caused by the guest phase.

  13. Determination of melting point of vegetable oils and fats by differential scanning calorimetry (DSC) technique.

    OpenAIRE

    Nassu, Renata Tieko; Guaraldo Gonçalves, Lireny Aparecida

    1999-01-01

    Melting point of fats is used to characterize oils and fats and is related to their physical properties, such as hardness and thermal behaviour. The present work shows the utilization of DSC technique on the determination of melting point of fats. In a comparison with softening point (AOCS method Cc 3-25), DSC values were higher than those obtained by AOCS method. It has occurred due to the fact that values obtained by DSC technique were taken when the fat had melted completely. DSC was also ...

  14. Direct Measurements of Half-Cycle Reaction Heats during Atomic Layer Deposition by Calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Lownsbury, James M. [Department; Gladden, James A. [Department; Campbell, Charles T. [Department; Department; Kim, In Soo [Materials; Martinson, Alex B. F. [Materials

    2017-10-05

    We introduce a new high-temperature adsorption calorimeter that approaches the ideal limit of a heat detector whereby the signal at any time is proportional to the heat power being delivered to the sample and prove its sensitivity for measuring pulse-to-pulse heats of half-reactions during atomic layer deposition (ALD) at 400 K. The heat dynamics of amorphous Al2O3 growth via sequential self-limiting surface reaction of trimethylaluminum (TMA) and H2O is clearly resolved. Calibration enables quantitation of the exothermic TMA and H2O half-reactions with high precision, -343 kJ/mol TMA and -251 kJ/mol H2O, respectively. A time resolution better than 1 ms is demonstrated, allowing for the deconvolution of at least two distinct surface reactions during TMA microdosing. It is further demonstrated that this method can provide the heat of reaction versus extent of reaction during each precursors half-reaction, thus providing even richer mechanistic information on the surface processes involved. The broad applicability of this novel calorimeter is demonstrated through excellent signal-to-noise ratios of less exothermic ALD half-reactions to produce TiO2 and MnO.

  15. The CMS ECAL Upgrade for Precision Crystal Calorimetry at the HL-LHC

    CERN Document Server

    Barria, Patrizia

    2017-01-01

    The electromagnetic calorimeter (ECAL) of the Compact Muon Solenoid Experiment (CMS) is operating at the Large Hadron Collider (LHC) in 2016 with proton-proton collisions at 13 TeV center-of-mass energy and at a bunch spacing of 25 ns. Challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL-LHC). We review the design and R and D studies for the CMS ECAL crystal calorimeter upgrade and present first test beam studies. Particular challenges at HL-LHC are the harsh radiation environment, the increasing data rates and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. We present test beam results of hadron irradiated PbWO crystals up to fluences expected at the HL-LHC. We also report on the R and D for the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

  16. The CMS ECAL Upgrade for Precision Crystal Calorimetry at the HL-LHC

    CERN Document Server

    Jofrehei, Arash

    2017-01-01

    The Compact Muon Solenoid Experiment (CMS) is operating at the Large Hadron Collider (LHC) with proton-proton collisions at 13 TeV center-of-mass energy and at a bunch spacing of 25 ns. Challenging running conditions for CMS are expected after the High-Luminosity upgrade of the LHC (HL-LHC). We review the CMS ECAL crystal calorimeter upgrade and present results from the first test beam studies. Particular challenges at HL-LHC are the harsh radiation environment, the increasing data rates and the extreme level of pile-up events, with up to 200 simultaneous proton-proton collisions. Precision timing can be exploited to reduce the effect of the pile-up. We report on the timing resolution studies performed with test-beams. We discuss the new readout and trigger electronics, which must be upgraded due to the increased trigger and latency requirements at the HL-LHC.

  17. Thermodynamics of ligand binding to acyl-coenzyme A binding protein studied by titration calorimetry

    DEFF Research Database (Denmark)

    Færgeman, Nils J.; Sigurskjold, B W; Kragelund, B B

    1996-01-01

    Ligand binding to recombinant bovine acyl-CoA binding protein (ACBP) was examined using isothermal microcalorimetry. Microcalorimetric measurements confirm that the binding affinity of acyl-CoA esters for ACBP is strongly dependent on the length of the acyl chain with a clear preference for acyl-...

  18. Kinetic characteristics of polygalacturonase enzymes hydrolyzing galacturonic acid oligomers using isothermal titration calorimetry

    Science.gov (United States)

    Polygalacturonase enzymes hydrolyze the polygalacturonic acid chains found in pectin. Interest in polygalacturonase enzymes continues as they are useful in a number of industrial processes and conversely, detrimental, as they are involved in maceration of economically important crops. While a good...

  19. Thermodynamics of the adsorption of organic cations on kaolinite : temperature dependence and calorimetry

    NARCIS (Netherlands)

    Mehrian Isfahany, T.

    1992-01-01

    The present work is aimed at understanding the interactions involved in the adsorption of cationic surfactants on heterogeneous surfaces. The relevance of the study derives from the environmental aspects of the adsorption of small organic molecules onto soil constituents. This thesis

  20. Nuclear heating measurements by in-pile calorimetry: prospective works for a microsensor design

    Energy Technology Data Exchange (ETDEWEB)

    Reynard-Carette, C.; Carette, M.; Aguir, K.; Bendahan, M.; Fiorido, T. [Aix Marseille Universite, CNRS, Universite de Toulon, IM2NP UMR 7334, 13397, Marseille (France); Lyoussi, A.; Fourmentel, D.; Villard, J.F. [CEA, DEN, DER, Instrumentation Sensors and Dosimetry Laboratory, Cadarache, F-13108 (France); Barthes, M.; Lanzetta, F.; Layes, G.; Vives, S. [FEMTO-ST, UMR 6174, Departement ENERGIE, Universite de Franche-Comte, 90000, Belfort (France)

    2015-07-01

    Since 2009 works have been performed in the framework of joint research programs between CEA and Aix-Marseille University. The main aim of these programs is to design and develop in-pile instrumentations, advanced calibration procedure and accurate measurement methods in particular for the new Material Testing Reactor (MTR) under construction in the South of France: Jules Horowitz Reactor (JHR). One major sensor is a specific radiometric calorimeter, which was studied out-of-pile from a thermal point of view and in-pile during irradiation campaigns. This sensor type is dedicated to measurements of nuclear heating (energy deposition rate per mass unit induced by interactions between nuclear rays and matter) inside experimental channels of MTRs. This kind of in-pile calorimeter corresponds to heat flux calorimeter exchanging with the external cooling fluid. This thermal running mode allows the establishment of steady thermal conditions inside the sensor to carry out online continuous measurements inside the reactor (core or reflector). Two main types of calorimeters exist. The first type consists of a single cell calorimeter. It is divided into a sample of material to be tested and a jacket instrumented with two thermocouples or a single thermocouple (Gamma Thermometer). The second, called a differential calorimeter, is composed of two superposed twin cells (a measurement cell containing a sample of material, and a reference cell to remove the heating of the cell body) instrumented with four thermocouples and two electrical heaters. Contrary to a single-cell calorimeter, a differential calorimeter allows the compensation of the parasite nuclear heating of the sensor body or jacket. Moreover, it possesses interesting advantages: thanks to the heaters embedded in the cells, three different measurement methods can be applied during irradiations to quantify nuclear heating. The first one is based on the use of out-of-pile calibration curves obtained by generating a heat source by the Joule Effect inside each calorimetric cell. The second one is a zero method consisting in cancelling the difference in cell responses with an additional energy into the reference cell. The last measurement method is based on current additions in the two calorimetric cells. However, one drawback of the existing differential calorimeter is the size of the sensor: a great length equal to 220 mm and a diameter equal to 18 mm. This current size leads to measurement limitations. This paper will begin with a presentation of these measurement limitations from a bibliographic state. Each limitation will be detailed and in particular in the case of a high nuclear heating level expected, for instance, inside the JHR's core at its highest nominal power. The second part of the paper will develop the scientific skills of each partner in heat sciences, micro technology and nuclear physics necessary to design a new calorimetric micro-system: the advantages of studied microelements such as micro-thermocouples, micro- fluxmeters and micro-heaters will be presented. The last part will discuss preliminary designs. (authors)