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1

Differential Scanning Calorimetry (DSC) for planetary surface exploration  

NASA Technical Reports Server (NTRS)

Differential Scanning Calorimetry (DSC) is the quantitative measurement of the enthalpic response of a material to a systematic change in temperature. In practice, the heat flow into or outward from a sample is measured as the sample is heated or cooled at a carefully controlled rate. DSC superficially resembles, but is not the same as differential thermal analysis (DTA), which is the measurement of temperature differences between a sample and reference material as the pair is heated or cooled. The fundamental properties measured by DSC are enthalpies and temperatures of phase transitions and constant-pressure heat capacities. Depending on instrument design and the nature of the sample, high-quality DSC analyses can be obtained on only a few milligrams of solid materials. DSC requires direct contact with the sample and generally degrades, if not destroys, the sample as a consequence of heating. In laboratory applications, it is common to subject the gaseous effluent from the DSC to analysis by a separate evolved-gas analyzer (EGA).

Gooding, James L.; Ming, Douglas W.

1993-01-01

2

Determination of Purity by Differential Scanning Calorimetry (DSC).  

ERIC Educational Resources Information Center

An exercise is presented which demonstrates the determination of sample purity by differential scanning calorimetry. Data and references are provided to enable the exercise to be carried out as a dry-lab experiment. (BB)

Brown, M. E.

1979-01-01

3

Thermodynamic properties of diosgenin determined by oxygen-bomb calorimetry and DSC  

NASA Astrophysics Data System (ADS)

The combustion enthalpy of diosgenin was determined by oxygen-bomb calorimetry. The standard mole combustion enthalpy and the standard mole formation enthalpy have been calculated to be -16098.68 and -528.52 kJ mol-1, respectively. Fusion enthalpy and melting temperature for diosgenin were also measured to be -34.43 kJ mol-1 and 212.33°C, respectively, according to differential scanning calorimetry (DSC) data. These studies can provide useful thermodynamic data for this compound.

Zhao, Ming-Rui; Wang, Hong-Jie; Wang, Shu-Yu; Yue, Xiao-Xin

2014-12-01

4

Anisotropic-isotropic transition of solutions of cellulose derivatives: a DSC study. [Differential scanning calorimetry  

SciTech Connect

Cellulose acetate (CA)/trifluoroacetic acid (TFA), cellulose triacetate (CTA)/trifluoroacetic acid, and hydroxypropylcellulose (HPC)/water solutions are able to develop liquid crystalline (cholesteric) order above a certain polymer concentration C/sup **/. When the polymer concentration C is smaller than C/sup **/, no peak is recorded on a DSC trace upon heating. When C>C/sup **/, a well-defined peak for CA/TFA appears at a temperature T/sub t/. This peak is attributed to the anisotropic-isotropic phase transition. The origin and nature of this peak are discussed in the light of available theories. A T/sub t/-C phase diagram is plotted. For CTA/TFA solutions, one or two peaks arise, depending onpolymer concentration. The peak at the higher temperature is attributed to the anisotropic-isotropic transition, and the peak at the lower temperature to the destruction of a ''gel-like'' phase. HPC/water solutions have a very different behavior. Upon heating, they are transformed into a turbid phase regardless of the concentration. 22 references, 11 figures, 1 table.

Navard, P.; Haudin, J.M.; Dayan, S.; Sixou, P.

1983-01-01

5

The effect of humidity on dehydration behavior of nitrofurantoin monohydrate studied by humidity controlled simultaneous instrument for X-ray Diffractometry and Differential Scanning Calorimetry (XRD–DSC)  

Microsoft Academic Search

The dependence of thermal dehydration behavior of nitrofurantoin monohydrate on humidity was studied. Difference in observed crystallinity of resulting anhydrates under three humidity conditions is discussed in relation to the effect of water vapor molecules. Thermal dehydration of nitrofurantoin monohydrate was measured using a humidity controlled simultaneous measurement instrument for X-ray Diffractometry (XRD) and Differential Scanning Calorimetry (DSC) in dry,

Akira Kishi; Makoto Otsuka; Yoshirisa Matsuda

2002-01-01

6

Differential Scanning Calorimetry (DSC) as a Tool for Probing the Reactivity of Polyynes Relevant to Hexadehydro-Diels-Alder (HDDA) Cascades.  

PubMed

The differential scanning calorimetry (DSC) behavior of a number of alkyne-rich compounds is described. The DSC trace for each compound exhibits an exothermic event at a characteristic onset temperature. For the tri- and tetraynes whose [4 + 2] HDDA reactivity in solution has been determined, these onset temperatures show a strong correlation with the cyclization activation energy. The studies reported here exemplify how the data available through this operationally simple analytical technique can give valuable insights into the thermal behavior of small molecules. PMID:25470072

Woods, Brian P; Hoye, Thomas R

2014-12-19

7

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)  

SciTech Connect

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.

Rodriguez, Carmen P. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Pierce, David A. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Schweiger, Michael J. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Kruger, Albert A. [USDOE Office of River Protection, Richland, WA (United States); Chun, Jaehun [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); ; Hrma, Pavel R. [Pacific Northwest National Laboratory (PNNL), Richland, WA (United States);

2013-12-03

8

Differential Scanning Calorimetry Techniques: Applications in Biology and Nanoscience  

PubMed Central

This paper reviews the best-known differential scanning calorimetries (DSCs), such as conventional DSC, microelectromechanical systems-DSC, infrared-heated DSC, modulated-temperature DSC, gas flow-modulated DSC, parallel-nano DSC, pressure perturbation calorimetry, self-reference DSC, and high-performance DSC. Also, we describe here the most extensive applications of DSC in biology and nanoscience. PMID:21119929

Gill, Pooria; Moghadam, Tahereh Tohidi; Ranjbar, Bijan

2010-01-01

9

Correlating DSC and X-Ray Measurements Of Crystallinity  

NASA Technical Reports Server (NTRS)

Experiment demonstrated approximate linear correlation between degree of crystallinity of multiphase polymer (as calculated from x-ray diffraction measurements) and heat of fusion of polymer (as calculated from differential scanning calorimetry (DSC) measurements). Correlation basis of simple new technique for estimating degree of crystallinity of specimens of polymer from DSC measurements alone.

Yen, Shiao-Ping S.; Lowry, Lynn E.; Bankston, Clyde P.

1991-01-01

10

Identifying Hydrated Salts Using Simultaneous Thermogravimetric Analysis and Differential Scanning Calorimetry  

ERIC Educational Resources Information Center

simultaneous thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) to characterize colorless, hydrated salts with anhydrous melting points less than 1100 degrees C. The experiment could be used to supplement the lecture discussing gravimetric techniques. It is…

Harris, Jerry D.; Rusch, Aaron W.

2013-01-01

11

Bomb Calorimetry  

NSDL National Science Digital Library

This site provides an animated overview (and actual performance) of a bomb calorimetry experiment. It would serve as a good introduction or review for students about to perform this experiment in the laboratory.

12

Laboratory Annealing Experiments Of Refractory Silicate Grain Analogs Using Differential Scanning Calorimetry  

NASA Technical Reports Server (NTRS)

Exothermic reactions during the annealing of laboratory synthesized amorphous magnesium-bearing silicate particles used as grain analogs of cosmic dust were detected by differential scanning calorimetry (DSC) in air. With infrared spectroscopy and transmission electron microscopy, we show that cosmic dust could possibly undergo fusion to larger particles, with oxidation of magnesium silicide and crystallization of forsterite as exothermic reactions in the early solar system. The reactions begin at approximately 425, approximately 625, and approximately 1000 K, respectively, and the reaction energies (enthalpies) are at least 727, 4151, and 160.22 J per gram, respectively. During the crystallization of forsterite particles, the spectral evolution of the 10 micrometer feature from amorphous to crystalline was observed to begin at lower temperature than the crystallization temperature of 1003 K. During spectral evolution at lower temperature, nucleation and/or the formation of nanocrystallites of forsterite at the surface of the grain analogs was observed.

Kimura, Yuki; Nuth, Joseph A., III; Tsukamota, Katsuo; Kaito, Chihiro

2010-01-01

13

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

PubMed

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?M>KD>1nM. 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 (?H) 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. PMID:25461813

Krainer, Georg; Keller, Sandro

2014-11-13

14

The Enthalpy of Decomposition of Hydrogen Peroxide: A General Chemistry Calorimetry Experiment  

NASA Astrophysics Data System (ADS)

A calorimetry experiment involving the catalytic decomposition of aqueous hydrogen peroxide is presented. The experiment is simple, inexpensive, and colorful. In its simplest form, it can be performed in less than one hour; therefore, it is quite suitable for high school labs, which often have time restrictions. The chemicals required are household or commercial 3% H2O2(aq) and 0.50 M Fe(NO3)3(aq). Styrofoam cup calorimeters and thermometers with a range from 20 to 50 oC are also required. Ideally, the thermometers should be precise to 0.01 oC. The temperature of the H2O2 solution is monitored before and after the Fe(NO3)3 catalyst is added. The addition of the catalyst results in a color change and the evolution of heat and bubbles of oxygen. At the conclusion of the reaction, the color of the reaction mixture returns to that of the original Fe(NO3)3 solution. The heat change for the reaction is determined from the temperature change, the specific heat of the solution, and the calorimeter constant. The experimental enthalpy change for the reaction is in excellent agreement with the literature value.

Marzzacco, Charles J.

1999-11-01

15

Dynamic Calorimetry for Students  

ERIC Educational Resources Information Center

A student experiment on dynamic calorimetry is described. Dynamic calorimetry is a powerful technique for calorimetric studies, especially at high temperatures and pressures. A low-power incandescent lamp serves as the sample. The ScienceWorkshop data-acquisition system with DataStudio software from PASCO Scientific displays the results of the…

Kraftmakher, Yaakov

2007-01-01

16

Neutron monitoring and electrode calorimetry experiments in the HIP-1 Hot Ion Plasma  

NASA Technical Reports Server (NTRS)

Results are presented for two diagnostic procedures on HIP-1: neutron diagnostics to determine where neutrons originated within the plasma discharge chamber and electrode calorimetry to measure the steady-state power absorbed by the two anodes and cathodes. Results are also reported for a hot-ion plasma formed with a continuous-cathode rod, one that spans the full length of the test section, in place of the two hollow cathodes. The outboard neutron source strength increased relative to that at the midplane when (1) the cathode tips were moved farther outboard, (2) the anode diameters were increased, and (3) one of the anodes was removed. The distribution of neutron sources within the plasma discharge chamber was insensitive to the division of current between the two cathodes. For the continuous cathode, increasing the discharge current increased the midplane neutron source strength relative to the outboard source strength. Each cathode absorbed from 12 to 15 percent of the input power regardless of the division of current between the cathodes. The anodes absorbed from 20 to 40 percent of the input power. The division of power absorption between the anodes varied with plasma operating conditions and electrode placement.

Reinmann, J. J.; Layman, R. W.

1977-01-01

17

Physical ageing studies of poly(ethylene terephthalate) using SANS and DSC  

NASA Astrophysics Data System (ADS)

The process of physical ageing in a blend of deuterated and hydrogenated poly(ethylene terephalate) has been investigated using a combination of differential scanning calorimetry (DSC) and small-angle neutron scattering (SANS). The development of an endothermic peak on the glass transition has been shown using DSC. Furthermore, the radius of gyration was found to decrease during physical ageing.

Ellis, Andrew; Gordon, Duncan; King, Stephen; Jenkins, Mike

2006-11-01

18

Pyrene Fluorescence as a Probe for the Monitoring of Polymerization Processes: Simultaneous DSC and Fluorescence Study  

Microsoft Academic Search

The polymerization of cyclohexylmethacrylate was monitored, over a wide temperature range, by simultaneous differential scanning calorimetry (DSC) and fluorimetry (FL); the equipment for both being optically coupled. Pyrene was used as a fluorescent probe. There was excellent agreement between the exothermic peak time obtained by DSC and the time at which the maximum gradient was obtained in the fluorescence intensity–time

B. Serrano; J. C. Cabanelas; J. González-Benito; J. Baselga; J. Bravo

1997-01-01

19

Quantitative description of temperature induced self-aggregation thermograms determined by differential scanning calorimetry.  

PubMed

A novel thermodynamic approach for the description of differential scanning calorimetry (DSC) experiments on self-aggregating systems is derived and presented. The method is based on a mass action model where temperature dependence of aggregation numbers is considered. The validity of the model was confirmed by describing the aggregation behavior of poly(ethylene oxide)-poly(propylene oxide) block copolymers, which are well-known to exhibit a strong temperature dependence. The quantitative description of the thermograms could be performed without any discrepancy between calorimetric and van 't Hoff enthalpies, and moreover, the aggregation numbers obtained from the best fit of the DSC experiments are in good agreement with those obtained by light scattering experiments corroborating the assumptions done in the derivation of the new model. PMID:23171124

Chiappisi, Leonardo; Lazzara, Giuseppe; Gradzielski, Michael; Milioto, Stefana

2012-12-21

20

Determination of the oxidative stability by DSC of vegetable oils from the Amazonian area.  

PubMed

Differential scanning calorimetry (DSC) and a Rancimat method apparatus were applied to evaluate the oxidative stability of buriti pulp oil (Mauritia flexuosa Mart), rubber seed oil (Hevea brasiliensis), and passion fruit oil (Passiflora edulis). The Rancimat measurements taken for the oxidative induction times were performed under isothermal conditions at 100°C and in an air atmosphere. The DSC technique involved the oxidation of oil samples in an oxygen-flow DSC cell. The DSC cell temperature was set at five different isothermal temperatures: 100, 110, 120, 130 and 140°C. During the oxidation reaction, an increase in heat was observed as a sharp exothermic curve. The value T(0) represents the oxidative induction time, which is determined from the downward extrapolated DSC oxidative curve verses the time axis. These curves indicate a good correlation between the DSC T(0) and oxidative stability index (OSI) values. The DSC method is useful because it consumes less time and less sample. PMID:21411317

Pardauil, Juliana J R; Souza, Luiz K C; Molfetta, Fábio A; Zamian, José R; Rocha Filho, Geraldo N; da Costa, C E F

2011-05-01

21

Differential scanning calorimetry to quantify the stability of protein cages.  

PubMed

Differential scanning calorimetry (DSC) is an experimental technique through which the differences in amount of heat required to maintain equal temperature between a sample and a reference cell are measured at various temperatures. The quantified heat relates to the differences in apparent heat capacity of the analytes. The data from DSC studies will thereby provide direct information about the energetics of thermally induced processes in the sample. Here we present a detailed protocol to quantify the thermostability of protein cage, bacterioferritin (BFR), using differential scanning calorimetry. PMID:25358777

Zhang, Yu; Ardejani, Maziar S

2015-01-01

22

PURITY AND HEAT OF FUSION DATA FOR ENVIRONMENTAL STANDARDS AS DETERMINED BY DIFFERENTIAL SCANNING CALORIMETRY  

EPA Science Inventory

Differential scanning calorimetry (DSC) has been applied to 273 environmental standards, including pesticides, herbicides and related compounds. embers of the following chemical classes were analyzed: rganophosphorus, organochlorine, phenol, triazine, uracil, phenoxy acid, urea, ...

23

Effect of critical molecular weight of PEO in epoxy/EPO blends as characterized by advanced DSC and solid-state NMR  

NASA Astrophysics Data System (ADS)

The differential scanning calorimetry (DSC) and solid state NMR have been used to systematically study the length scale of the miscibility and local dynamics of the epoxy resin/poly(ethylene oxide) (ER/PEO) blends with different PEO molecular weight. By DSC, we found that the diffusion behavior of PEO with different Mw is an important factor in controlling these behaviors upon curing. We further employed two-dimensional 13C-1HPISEMA NMR experiment to elucidate the possible weak interaction and detailed local dynamics in ER/PEO blends. The CH2O group of PEO forms hydrogen bond with hydroxyl proton of cured-ER ether group, and its local dynamics frozen by such interaction. Our finding indicates that molecular weight (Mw) of PEO is a crucial factor in controlling the miscibility, chain dynamics and hydrogen bonding interaction in these blends.

Wang, Xiaoliang; Lu, Shoudong; Sun, Pingchuan; Xue, Gi

2013-03-01

24

Investigation of glass-ionomer cements using differential scanning calorimetry.  

PubMed

Six commercial glass-ionomer cements commonly used for various dental applications have been investigated using differential scanning calorimetry (DSC). The heat-flow behaviour and heat capacity of the cements were measured during isothermal (at 37 degrees C) setting reactions. The DSC results show that all materials undergo an exothermic setting process, but with different enthalpies of reactions and different heat capacities; there are no remaining endo- or exothermic reactions after the setting of the cement. All materials examined were found to be effective thermal insulators. PMID:15348851

Khalil, S K; Atkins, E D

1998-09-01

25

Domain analysis of human apotransferrin upon interaction with sodium n-dodecyl sulphate: differential scanning calorimetry and circular dichroism approaches  

Microsoft Academic Search

The domain analysis of human apotransferrin (apo hTF) upon interaction with sodium n-dodecyl sulphate (SDS) was studied by differential scanning calorimetry (DSC) and circular dichroism (CD) using Hepes buffer, 100mM, at pH=7. The DSC profile for apo hTF depicts two distinct peaks, while when interacted with SDS, the DSC peaks are shifted to the left as well as the area

M. Rezaei-Tavirani; A. A. Moosavi-Movahedi; S. Z. Moosavi-Nejad; J. Chamani; D. Ajloo

2003-01-01

26

Mass fractal characteristics of wet sonogels as determined by small-angle x-ray scattering and differential scanning calorimetry  

Microsoft Academic Search

Low density silica sonogels were prepared from acid sonohydrolysis of tetraethoxysilane. Wet gels were studied by small-angle x-ray scattering (SAXS) and differential scanning calorimetry (DSC). The DSC tests were carried out under a heating rate of 2°C\\/min from -120°C up to 30°C . Aerogels were obtained by CO2 supercritical extraction and characterized by nitrogen adsorption and SAXS. The DSC thermogram

D. R. Vollet; D. A. Donatti; A. Ibañez Ruiz; F. R. Gatto

2006-01-01

27

Kinetics Characteristics of Nitrogen Hydrates Respond to Differential Scanning Calorimetry  

NASA Astrophysics Data System (ADS)

In this study, a high pressure differential scanning calorimetry (HP DSC) based on thermo-analytical technique was applied to investigate the kinetics and thermodynamics characteristics of nitrogen hydrates. Nitrogen hydrates was synthesized in the sample vessel under different pressures as temperature decreased from 293 to 233 K with a constant cooling rate of 0.2 K/min controlled by the DSC. To measure the hydrates dissociation enthalpies , the temperature was slowly raised up from 233 to 293 K at a constant rate ranging of 0.05 K/min. 1. Peak area on the heat flow curves represents the amount of heat during phase transition. In these experiments, the total water added to the sample vessel (mt) is already known. By integrating the peak areas of ice and hydrate, we know the total heats of ice (Qi) and hydrate (Qh), respectively. As the heat of ice per gram can be measured easily (336.366 J/g), the mass of ice (mi) can be obtain. Then, the dissociation heat of nitrogen hydrate per gram (Hh ) can be calculated by the equation: H(J/g)=Qh/(mt-mi) It is shown that the dissociation heats of nitrogen hydrates are a little larger than ice, but do not change a lot with different pressures. The average value of dissociation heat is 369.158 J/g. 2. During the DSC cooling stage, hydrate formed at temperature much lower than equilibrium. The biggest sub-cooling is about 291 K, while the smallest one is about 279 K. However, during these experiments, the pressure did not show obvious relationship with sub-cooling. It confirmed that even the proper conditions were achieved, formation was still a stochastic process. For one thing, due to the random distribution of dissolved gas in water, the interfacial tension and the water activity were not equal in the whole system. And if there was a free gas phase, which leads to different fugacity on water-gas interface, the stochastic behavior would be more significant in the sample vessel. 3. The energy released from hydrates formation as a function of time can be obtained by integrating the exothermic peaks. As a series of experiments were carried out using the same bulk phase, these curves represented a semi-quantitative result of hydrate crystal growth speed (see Figure 1). The slope of the energy curve reflected the growth speed at a certain time. The steeper the curve became, the faster the hydrates growth was. As could be expected, hydrate growth speed is extremely dependent of the sub-cooling.; Figure 1. Energy released of hydrates growth as a function of time

Chen, Q.; Liu, C.; Ye, Y.; Gong, J.

2012-12-01

28

X-ray diffraction pattern and DSC curves of the discharge product of the lithium\\/sulfur dioxide battery  

Microsoft Academic Search

The X-ray diffraction pattern for the discharge product of the Li\\/SO2 battery has been determined. The diffraction data for the lithium dithionite (Li2S2O4) is presented in a table. Differential scanning calorimetry (DSC) data have indicated that Li2S2O4 undergoes two endothermic reactions and one exothermic reaction. The DSC data reveal also that Li reacts exothermically with Li2S2O4 at the lower endothermic

D. W. Ernst

1982-01-01

29

Calorimetry for the SSC  

SciTech Connect

The activities related to calorimetry at Snowmass took place in three main areas. These were: (1) The performance criteria for SSC calorimetry, including the requirements on hermeticity, shower containment, segmentation and time resolution. The use of calorimetric means of particle identification was studied. (2) The study of triggering methods using calorimeter energy, angle and timing information. (3) A review of a wide variety of calorimeter materials for absorber and sampling, as well as several means of obtaining the readout of the energy deposits. 48 references, 10 figures, 1 table.

Gordon, H.A.; Grannis, P.D.

1984-01-01

30

Scintillator materials for calorimetry  

SciTech Connect

Requirements for fast, dense scintillator materials for calorimetry in high energy physics and approaches to satisfying these requirements are reviewed with respect to possible hosts and luminescent species. Special attention is given to cerium-activated crystals, core-valence luminescence, and glass scintillators. The present state of the art, limitations, and suggestions for possible new scintillator materials are presented.

Weber, M.J. [Lawrence Berkeley Lab., CA (United States). Life Sciences Div.

1994-09-01

31

Differential scanning calorimetry of water buffalo and cow milk fat in mozzarella cheese  

Microsoft Academic Search

The thermal profiles of the fat in mozzarella cheeses made from cow milk (CM) and water buffalo milk (WBM) were obtained by\\u000a differential scanning calorimetry (DSC). The DSC curves of mozzarella cheese made from WBM were distinguishable from those\\u000a of CM. The curves resembled those of the corresponding milk fats and could be divided into low-, medium-, and high-temperature\\u000a melting

Michael H. Tunick; Edyth L. Malin

1997-01-01

32

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

PubMed Central

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°C shift in Tm to higher temperature. A similar effect was observed in the case of the nonhydrolyzable AMP.PNP analogue. Differential DSC measurements suggest that stabilization actin structure in the intermediate states of ATP hydrolysis may play an additional role in actin-myosin interaction. PMID:17588264

Dergez, Timea; L?rinczy, Dénes; Könczöl, Franciska; Farkas, Nelli; Belagyi, Joseph

2007-01-01

33

Differential scanning calorimetry and fluorescence study of lactoperoxidase as a function of guanidinium-HCl, urea and pH  

PubMed Central

The stability of bovine lactoperoxidase to denaturation by guanidinium-HCl, urea or high temperature was examined by differential scanning calorimetry (DSC) and tryptophan fluorescence. The calorimetric scans were observed to be dependent upon the heating scan rate, indicating that lactoperoxidase stability at temperatures near Tm is controlled by kinetics. The values for the thermal transition, Tm, at slow heating scan rate were 66.8, 61.1 and 47.2°C in the presence of 0.5, 1 and 2 M guanidinium-HCl, respectively. Extrapolated value for Tm in the absence of guanidinium-HCl is 73.7°C, compared with 70.2°C obtained by experiment; a lower experimental value without denaturant is consistent with distortion of the thermal profile due to aggregation or other irreversible phenomenon. Values for the heat capacity, Cp, at Tm and Ea for the thermal transition decrease under conditions where Tm is lowered. At a given concentration, urea is less effective than guanidinium-HCl in reducing Tm, but urea reduces Cp relatively more. Both fluorescence and DSC indicate that thermally denatured protein is not random coil. A change in fluorescence around 35°C, which was previously reported for EPR and CD measurements (Boscolo et al. Biochim. Biophys. Acta 1174 (2007) 1164–1172), is not seen by calorimetry, suggesting that a local and not global change in protein conformation produces this fluorescence change. PMID:20298816

ZELENT, Bogumil; SHARP, Kim A.; VANDERKOOI, Jane M.

2010-01-01

34

DSC Study on Phase Transitions and Their Correlation with Properties of Overaged Al-Zn-Mg-Cu Alloys  

NASA Astrophysics Data System (ADS)

This article investigates the phase transitions of complex quaternary Al-Zn-Mg-Cu alloys with Zr addition at overaged conditions. Differential scanning calorimetry (DSC) is employed to quantitatively analyze the phase transformation phenomena of a wide range of 7xxx series alloys through endothermic and exothermic reactions. The DSC observations detailing heat effect peaks and thermal parameters of ?' dissolution contain valuable information on the presence of equilibrium phases and the optimum alloying element contents. Based on DSC experimental data and phase diagrams, the balance of critical properties such as strength and electrical conductivity of Al-Zn-Cu-Mg 7xxx series alloys has been studied by considering the formation, dissolution, and incipient melting of S and T phase, dissolution of ?' phase as well as the formation of ? phase. Nine Al-Zn-Mg-Cu alloys have been studied through microstructural examination and detailed DSC analysis. The correlation between the properties and the DSC data of the selected alloys has been analyzed.

Li, X. M.; Starink, M. J.

2012-06-01

35

Applications of high pressure differential scanning calorimetry to aviation fuel thermal stability research  

NASA Technical Reports Server (NTRS)

High pressure differential scanning calorimetry (DSC) was studied as an alternate method for performing high temperature fuel thermal stability research. The DSC was used to measure the heat of reaction versus temperature of a fuel sample heated at a programmed rate in an oxygen pressurized cell. Pure hydrocarbons and model fuels were studied using typical DSC operating conditions of 600 psig of oxygen and a temperature range from ambient to 500 C. The DSC oxidation onset temperature was determined and was used to rate the fuels on thermal stability. Kinetic rate constants were determined for the global initial oxidation reaction. Fuel deposit formation is measured, and the high temperature volatility of some tetralin deposits is studied by thermogravimetric analysis. Gas chromatography and mass spectrometry are used to study the chemical composition of some DSC stressed fuels.

Neveu, M. C.; Stocker, D. P.

1985-01-01

36

NMR, DSC and high pressure electrical conductivity studies of liquid and hybrid electrolytes  

Microsoft Academic Search

Electrical conductivity, differential scanning calorimetry (DSC) and 'Li nuclear magnetic resonance (NMR) studies have been carried out on liquid electrolytes such as ethylene carbonate:propylene carbonate (EC:PC) and ECdimethyl carbonate (DMC) containing LiPF, (and LiCFaSO, for NMR) and films plasticized using the same liquid electrolytes. The films are based on poly(vinylidene fluoride) (PVdF) copolymerized with hexafluoropropylene and contain fumed silica. All

P. E. Stallworth; J. J. Fontanella; M. C. Wintersgill; Christopher D. Scheidler; Jeffrey J. Immel; S. G. Greenbaum; A. S. Gozdz

1999-01-01

37

Effect of Oxygen Free Radicals on Myosin in Muscle Fibres. A DSC and EPR study  

Microsoft Academic Search

Differential scanning calorimetry (DSC) and electron paramagnetic resonance spectroscopy (EPR, both conventional and saturation\\u000a transfer EPR) were used to study the motional dynamics and segmental flexibility of myosin in muscle fibres in the presence\\u000a of free radical generating system.\\u000a \\u000a Muscle fibre bundles isolated from psoas muscle of rabbit were spin-labelled with maleimide- and isothiocyanate-based probe\\u000a molecules at the reactive sulfhydryl

D. L?rinczy; B. Gaszner; F. Könczöl; J. Belágyi

2000-01-01

38

In situ stability of substrate-associated cellulases studied by DSC.  

PubMed

This work shows that differential scanning calorimetry (DSC) can be used to monitor the stability of substrate-adsorbed cellulases during long-term hydrolysis of insoluble cellulose. Thermal transitions of adsorbed enzyme were measured regularly in subsets of a progressing hydrolysis, and the size of the transition peak was used as a gauge of the population of native enzyme. Analogous measurements were made for enzymes in pure buffer. Investigations of two cellobiohydrolases, Cel6A and Cel7A, from Trichoderma reesei, which is an anamorph of the fungus Hypocrea jerorina, showed that these enzymes were essentially stable at 25 °C. Thus, over a 53 h experiment, Cel6A lost less than 15% of the native population and Cel7A showed no detectable loss for either the free or substrate-adsorbed state. At higher temperatures we found significant losses in the native populations, and at the highest tested temperature (49 °C) about 80% Cel6A and 35% of Cel7A was lost after 53 h of hydrolysis. The data consistently showed that Cel7A was more long-term stable than Cel6A and that substrate-associated enzyme was less long-term stable than enzyme in pure buffer stored under otherwise equal conditions. There was no correlation between the intrinsic stability, specified by the transition temperature in the DSC, and the long-term stability derived from the peak area. The results are discussed with respect to the role of enzyme denaturation for the ubiquitous slowdown observed in the enzymatic hydrolysis of cellulose. PMID:24856176

Alasepp, Kadri; Borch, Kim; Cruys-Bagger, Nicolaj; Badino, Silke; Jensen, Kenneth; Sørensen, Trine H; Windahl, Michael S; Westh, Peter

2014-06-24

39

Thermal characterization and model free kinetics of aged epoxies and foams using TGA and DSC methods.  

SciTech Connect

Two classes of materials, poly(methylene diphenyl diisocyanate) or PMDI foam, and cross-linked epoxy resins, were characterized using thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), to help understand the effects of aging and %E2%80%9Cbake-out%E2%80%9D. The materials were evaluated for mass loss and the onset of decomposition. In some experiments, volatile materials released during heating were analyzed via mass spectroscopy. In all, over twenty materials were evaluated to compare the mass loss and onset temperature for decomposition. Model free kinetic (MFK) measurements, acquired using variable heating rate TGA experiments, were used to calculate the apparent activation energy of thermal decomposition. From these compiled data the effects of aging, bake-out, and sample history on the thermal stability of materials were compared. No significant differences between aged and unaged materials were detected. Bake-out did slightly affect the onset temperature of decomposition but only at the highest bake-out temperatures. Finally, some recommendations for future handling are made.

Cordaro, Joseph Gabriel; Kruizenga, Alan Michael; Nissen, April

2013-10-01

40

Characteristics of Differential Scanning Calorimetry Determination of Thermophysical Properties of Meats  

Microsoft Academic Search

Differential scanning calorimetry (DSC) was used to determine the variations in heat capacity and enthalpy of beef and pork of differing composition, and in response to different temperatures. The values in relation to changes in temperature and composition differed from published reports and were also at variance with published equations. Similar results have been observed for lamb in previous work

Ana M. Tocci; Rodolfo H. Mascheroni

1998-01-01

41

Probing Perturbation of Bovine Lung Surfactant Extracts by Albumin using DSC and 2H-NMR  

PubMed Central

Lung surfactant (LS), a lipid-protein mixture, forms films at the lung air-water interface and prevents alveolar collapse at end expiration. In lung disease and injury, the surface activity of LS is inhibited by leakage of serum proteins such as albumin into the alveolar hypophase. Multilamellar vesicular dispersions of a clinically used replacement, bovine lipid extract surfactant (BLES), to which (2% by weight) chain-perdeuterated dipalmitoylphosphatidycholine (DPPG mixtures-d62) had been added, were studied using deuterium-NMR spectroscopy (2H-NMR) and differential scanning calorimetry (DSC). DSC scans of BLES showed a broad gel to liquid-crystalline phase transition between 10–35°C, with a temperature of maximum heat flow (Tmax) around 27°C. Incorporation of the DPPC-d62 into BLES-reconstituted vesicles did not alter the Tmax or the transition range as observed by DSC or the hydrocarbon stretching modes of the lipids observed using infrared spectroscopy. Transition enthalpy change and 2H-NMR order parameter profiles were not significantly altered by addition of calcium and cholesterol to BLES. 2H-NMR spectra of the DPPC-d62 probes in these samples were characteristic of a single average lipid environment at all temperatures. This suggested either continuous ordering of the bilayer through the transition during cooling or averaging of the DPPC-d62 environment by rapid diffusion between small domains on a short timescale relative to that characteristic of the 2H-NMR experiment. Addition of 10% by weight of soluble bovine serum albumin (1:0.1, BLES/albumin, dry wt/wt) broadened the transition slightly and resulted in the superposition of 2H-NMR spectral features characteristic of coexisting fluid and ordered phases. This suggests the persistence of phase-separated domains throughout the transition regime (5–35°C) of BLES with albumin. The study suggests albumin can cause segregation of protein bound-lipid domains in surfactant at NMR timescales (10?5 s). Persistent phase separation at physiological temperature may provide for a basis for loss of surface activity of surfactant in dysfunction and disease. PMID:16500977

Nag, Kaushik; Keough, Kevin M. W.; Morrow, Michael R.

2006-01-01

42

Aggregate structure of “single-nano buckydiamond” in gel and dried powder by differential scanning calorimetry and nitrogen adsorption  

Microsoft Academic Search

Gels and dried powders of the single-nano buckydiamond (SNBD) have been studied by means of differential scanning calorimetry (DSC) and gas adsorption methods. Nanophase of water (NPhW) was confirmed in SNBD hydrogel by DSC, wherein the characteristic feature at 265K was observed and attributed to melting of NPhW. No such feature was observed in commercial agglutinate samples of detonation nanodiamond.

Mikhail V. Korobov; Maria M. Batuk; Natalia V. Avramenko; Nina I. Ivanova; Natalia N. Rozhkova; Eiji ?sawa

2010-01-01

43

Mass fractal characteristics of wet sonogels as determined by small-angle x-ray scattering and differential scanning calorimetry  

Microsoft Academic Search

Low density silica sonogels were prepared from acid sonohydrolysis of tetraethoxysilane. Wet gels were studied by small-angle x-ray scattering (SAXS) and differential scanning calorimetry (DSC). The DSC tests were carried out under a heating rate of 2 deg. C\\/min from -120 deg. C up to 30 deg. C. Aerogels were obtained by COâ supercritical extraction and characterized by nitrogen adsorption

D. R. Vollet; D. A. Donatti; A. Ibanez Ruiz; F. R. Gatto

2006-01-01

44

OXIDATIVE STABILITY OF BIODIESEL BY DYNAMIC MODE PRESSURIZED-DIFFERENTIAL SCANNING CALORIMETRY (P-DSC)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Biodiesel, an alternative diesel fuel made from transesterification of vegetable oils or animal fats, is composed of saturated and unsaturated long-chain fatty acid alkyl esters. During long-term storage, oxidation caused by contact with ambient air presents legitimate concerns for monitoring fuel ...

45

Analysis of Cooperativity by Isothermal Titration Calorimetry  

PubMed Central

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. PMID:20111687

Brown, Alan

2009-01-01

46

Characterization of the evaluation of the solid solubility of Si in sintered Fe-Si alloys using DSC technique  

SciTech Connect

Differential scanning calorimeter (DSC) is used to quantify the solid solubility of Si in sintered Fe-Si alloys. The calorimetry tests are run on Fe-Si alloys by arc melting and sintering. The relationship between the Curie temperature and the solid solubility of Si in Fe-Si alloys was determined using DSC. The solid solubility of Si in sintered Fe-Si alloys evaluated according to the relationship between magnetic transition and compositions can be compared with the results from a related quantitative electron probe microanalysis (EPMA)

Yuan, W.J. [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)]. E-mail: wjyuanwut@yahoo.com.cn; Li, R. [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); School of Materials Science and Engineering, Beijing University of Aeronautics and Astronautics, Beijing 100083 (China); Shen, Q. [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China); Zhang, L.M. [State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (China)

2007-04-15

47

TGA/FTIR and DSC/FTIR: combined approaches to solving problems  

NASA Astrophysics Data System (ADS)

Thermal analysis of complex samples has been greatly assisted by the coupling of FT-IR analysis to the TA experiment, and evolved gas analysis by infrared spectroscopy has been very successful in combined TGA/FT-IR experiments. During a combined DSC/FT-IR experiment the FT-IR analysis is performed on the sample itself, by using an infrared transmitting microscope. A curing reaction and thermal changes in a polymer are used to demonstrate the use of a combined DSC/FT-IR system. By combining a simultaneous TGA/DSC instrument with FT-IR evolved gas analysis, we are now able to obtain three sets of complementary information, on the same sample, in one experiment. A study of the thermal behavior of zinc stearate is reported by using TGA/DSC/FT-IR.

Compton, David A. C.; Powell, Jay R.; Crocombe, Richard A.

1992-03-01

48

Differential Scanning Calorimetry Glass Transition Temperatures of White Bread and Mold Growth in the Putative Glassy State  

Microsoft Academic Search

Cereal Chem. 75(1):64-69 Differential scanning calorimetry (DSC) was used to determine the onset and end temperatures of the glass transition ( Tg) for white bread equilibrated between 53 and 84% rh. Calorimetric Tg end values were ?20°C higher than onset values, indicating that it is probably more cor- rect to refer to a \\

M. P. Buera; K. Jouppila; Y. H. Roos; J. Chirife

1998-01-01

49

Characterization of the polycaprolactone melt crystallization: complementary optical microscopy, DSC, and AFM studies.  

PubMed

The first stages of the crystallization of polycaprolactone (PCL) were studied using several techniques. The crystallization exotherms measured by differential scanning calorimetry (DSC) were analyzed and compared with results obtained by polarized optical microscopy (POM), rheology, and atomic force microscope (AFM). The experimental results suggest a strong influence of the observation scale. In particular, the AFM, even if limited on time scale, appears to be the most sensitive technique to detect the first stages of crystallization. On the contrary, at least in the case analysed in this work, rheology appears to be the least sensitive technique. DSC and POM provide closer results. This suggests that the definition of induction time in the polymer crystallization is a vague concept that, in any case, requires the definition of the technique used for its characterization. PMID:24523644

Speranza, V; Sorrentino, A; De Santis, F; Pantani, R

2014-01-01

50

Characterization of the Polycaprolactone Melt Crystallization: Complementary Optical Microscopy, DSC, and AFM Studies  

PubMed Central

The first stages of the crystallization of polycaprolactone (PCL) were studied using several techniques. The crystallization exotherms measured by differential scanning calorimetry (DSC) were analyzed and compared with results obtained by polarized optical microscopy (POM), rheology, and atomic force microscope (AFM). The experimental results suggest a strong influence of the observation scale. In particular, the AFM, even if limited on time scale, appears to be the most sensitive technique to detect the first stages of crystallization. On the contrary, at least in the case analysed in this work, rheology appears to be the least sensitive technique. DSC and POM provide closer results. This suggests that the definition of induction time in the polymer crystallization is a vague concept that, in any case, requires the definition of the technique used for its characterization. PMID:24523644

Speranza, V.; Sorrentino, A.; De Santis, F.; Pantani, R.

2014-01-01

51

One-step Real-time Food Quality Analysis by Simultaneous DSC-FTIR Microspectroscopy.  

PubMed

Abstract This review discusses an analytical technique that combines differential scanning calorimetry and Fourier-transform infrared (DSC-FTIR) microspectroscopy, which simulates the accelerated stability test and detects decomposition products simultaneously in real time. We show that the DSC-FTIR technique is a fast, simple and powerful analytical tool with applications in food sciences. This technique has been applied successfully to the simultaneous investigation of: encapsulated squid oil stability; the dehydration and intramolecular condensation of sweetener (aspartame); the dehydration, rehydration and solidification of trehalose; and online monitoring of the Maillard reaction for glucose (Glc)/asparagine (Asn) in the solid state. This technique delivers rapid and appropriate interpretations with food science applications. PMID:24762327

Lin, Shan-Yang; Lin, Chih-Cheng

2014-04-24

52

Intracellular ice formation in yeast cells vs. cooling rate: Predictions from modeling vs. experimental observations by differential scanning calorimetry?  

PubMed Central

To survive freezing, cells must not undergo internal ice formation during cooling. One vital factor is the cooling rate. The faster cells are cooled, the more their contents supercool, and at some subzero temperature that supercooled cytoplasm will freeze. The question is at what temperature? The relation between cooling rate and cell supercooling can be computed. Two important parameters are the water permeability (Lp) and its temperature dependence. To avoid intracellular ice formation (IIF), the supercooling must be eliminated by dehydration before the cell cools to its ice nucleation temperature. With an observed nucleation temperature of ?25°C, the modeling predicts that IIF should not occur in yeast cooled at <20°C/min and it should occur with near certainty in cells cooled at ? 30°C/min. Experiments with differential scanning calorimetry (DSC) confirmed these predictions closely. The premise with the DSC is that if there is no IIF, one should see only a single exotherm representing the freezing of the external water. If IIF occurs, one should see a second, lower temperature exotherm. A further test of whether this second exotherm is IIF is whether it disappears on repeated freezing. IIF disrupts the plasma membrane; consequently, in a subsequent freeze cycle, the cell can no longer supercool and will not exhibit a second exotherm. This proved to be the case at cooling rates > 20°C/min. PMID:19118541

Seki, Shinsuke; Kleinhans, F.W.; Mazur, Peter

2013-01-01

53

Ice in Prefermented Frozen Bread Dough—An Investigation Based on Calorimetry and Microscopy  

Microsoft Academic Search

Cereal Chem. 82(3):251-255 The amount, morphology, and distribution of ice in prefermented frozen bread dough were investigated by differential scanning calorimetry (DSC) and cryoscanning electron microscopy (cryo-SEM). Bread dough was frozen after proofing, stored frozen at -22 ± 3°C and analyzed without previous thawing. At constant storage conditions, the ice fraction amounted to 53% of the total water and remained

A. Baier-Schenk; S. Handschin; B. Conde-Petit

2005-01-01

54

Fourier transform infrared spectroscopy and differential scanning calorimetry studies of fatty acid homogeneous ceramide 2  

Microsoft Academic Search

Ceramides provide a major component of the barrier function of skin. An understanding of barrier organization requires a detailed characterization of ceramide phase behavior and molecular interactions. Toward this end, Fourier transform infrared (FTIR) and differential scanning calorimetry (DSC) studies of ceramide 2 analogues (non-hydroxylated fatty acid N-acyl sphingosines) of specific chain lengths (C14, C16, C18, C20) are presented. In

Hui-Chen Chen; Richard Mendelsohn; Mark E. Rerek; David J. Moore

2000-01-01

55

Interactions of Starch and Sugar Water Measured by Electron Spin Resonance and Differential Scanning Calorimetry  

Microsoft Academic Search

Cereal Chem. 67(3):286-291 Electron spin resonance (ESR) was used to evaluate the mobility of of water was reduced or after heat treatment of starch-sugar-water mix- water in starch-water mixtures (12-50% H2 0); ESR and differential scan- tures. The sugars progressively raised the temperature of starch gelatiniza- ning calorimetry (DSC) were used to study the effect of different sugars tion measured

J. M. JOHNSON; E. A. DAVIS; J. GORDON

56

Calorimetry Triggering in ATLAS  

SciTech Connect

The ATLAS experiment is preparing for data taking at 14 TeV collision energy. A rich discovery physics program is being prepared in addition to the detailed study of Standard Model processes which will be produced in abundance. The ATLAS multi-level trigger system is designed to accept one event in 2/10{sup 5} to enable the selection of rare and unusual physics events. The ATLAS calorimeter system is a precise instrument, which includes liquid Argon electro-magnetic and hadronic components as well as a scintillator-tile hadronic calorimeter. All these components are used in the various levels of the trigger system. A wide physics coverage is ensured by inclusively selecting events with candidate electrons, photons, taus, jets or those with large missing transverse energy. The commissioning of the trigger system is being performed with cosmic ray events and by replaying simulated Monte Carlo events through the trigger and data acquisition system.

Igonkina, O.; /NIKHEF, Amsterdam; Achenbach, R.; /Kirchhoff Inst. Phys.; Adragna, P.; /Queen Mary, U. of London; Aharrouche, M.; /Mainz U., Inst. Phys.; Alexandre, G.; /Geneva U.; Andrei, V.; /Kirchhoff Inst. Phys.; Anduaga, X.; /La Plata U.; Aracena, I.; /SLAC; Backlund, S.; /CERN; Baines, J.; /Rutherford; Barnett, B.M.; /Rutherford; Bauss, B.; /Mainz U., Inst. Phys.; Bee, C.; /Marseille, CPPM; Behera, P.; /Iowa State U.; Bell, P.; /Manchester U.; Bendel, M.; /Mainz U., Inst. Phys.; Benslama, K.; /Regina U.; Berry, T.; /Royal Holloway, U. of London; Bogaerts, A.; /CERN; Bohm, C.; /Stockholm U.; Bold, T.; /UC, Irvine /AGH-UST, Cracow /Birmingham U. /Barcelona, IFAE /CERN /Birmingham U. /Rutherford /Montreal U. /Santa Maria U., Valparaiso /DESY /DESY, Zeuthen /Geneva U. /City Coll., N.Y. /Barcelona, IFAE /CERN /Birmingham U. /Kirchhoff Inst. Phys. /Birmingham U. /Lisbon, LIFEP /Rio de Janeiro Federal U. /City Coll., N.Y. /Birmingham U. /Copenhagen U. /Copenhagen U. /Brookhaven /Rutherford /Royal Holloway, U. of London /Pennsylvania U. /Montreal U. /SLAC /CERN /Michigan State U. /Chile U., Catolica /City Coll., N.Y. /Oxford U. /La Plata U. /McGill U. /Mainz U., Inst. Phys. /Hamburg U. /DESY /DESY, Zeuthen /Geneva U. /Queen Mary, U. of London /CERN /Rutherford /Rio de Janeiro Federal U. /Birmingham U. /Montreal U. /CERN /Kirchhoff Inst. Phys. /Liverpool U. /Royal Holloway, U. of London /Pennsylvania U. /Kirchhoff Inst. Phys. /Geneva U. /Birmingham U. /NIKHEF, Amsterdam /Rutherford /Royal Holloway, U. of London /Rutherford /Royal Holloway, U. of London /AGH-UST, Cracow /Mainz U., Inst. Phys. /Mainz U., Inst. Phys. /Birmingham U. /Hamburg U. /DESY /DESY, Zeuthen /Geneva U. /Kirchhoff Inst. Phys. /Michigan State U. /Stockholm U. /Stockholm U. /Birmingham U. /CERN /Montreal U. /Stockholm U. /Arizona U. /Regina U. /Regina U. /Rutherford /NIKHEF, Amsterdam /Kirchhoff Inst. Phys. /DESY /DESY, Zeuthen /City Coll., N.Y. /University Coll. London /Humboldt U., Berlin /Queen Mary, U. of London /Argonne /LPSC, Grenoble /Arizona U. /Kirchhoff Inst. Phys. /Birmingham U. /Antonio Narino U. /Hamburg U. /DESY /DESY, Zeuthen /Kirchhoff Inst. Phys. /Birmingham U. /Chile U., Catolica /Indiana U. /Manchester U. /Kirchhoff Inst. Phys. /Rutherford /City Coll., N.Y. /Stockholm U. /La Plata U. /Antonio Narino U. /Queen Mary, U. of London /Kirchhoff Inst. Phys. /Antonio Narino U. /Pavia U. /City Coll., N.Y. /Mainz U., Inst. Phys. /Mainz U., Inst. Phys. /Pennsylvania U. /Barcelona, IFAE /Barcelona, IFAE /Chile U., Catolica /Genoa U. /INFN, Genoa /Rutherford /Barcelona, IFAE /Nevis Labs, Columbia U. /CERN /Antonio Narino U. /McGill U. /Rutherford /Santa Maria U., Valparaiso /Rutherford /Chile U., Catolica /Brookhaven /Oregon U. /Mainz U., Inst. Phys. /Barcelona, IFAE /McGill U. /Antonio Narino U. /Antonio Narino U. /Kirchhoff Inst. Phys. /Sydney U. /Rutherford /McGill U. /McGill U. /Pavia U. /Genoa U. /INFN, Genoa /Kirchhoff Inst. Phys. /Kirchhoff Inst. Phys. /Mainz U., Inst. Phys. /Barcelona, IFAE /SLAC /Stockholm U. /Moscow State U. /Stockholm U. /Birmingham U. /Kirchhoff Inst. Phys. /DESY /DESY, Zeuthen /Birmingham U. /Geneva U. /Oregon U. /Barcelona, IFAE /University Coll. London /Royal Holloway, U. of London /Birmingham U. /Mainz U., Inst. Phys. /Birmingham U. /Birmingham U. /Oregon U. /La Plata U. /Geneva U. /Chile U., Catolica /McGill U. /Pavia U. /Barcelona, IFAE /Regina U. /Birmingham U. /Birmingham U. /Kirchhoff Inst. Phys. /Oxford U. /CERN /Kirchhoff Inst. Phys. /UC, Irvine /UC, Irvine /Wisconsin U., Madison /Rutherford /Mainz U., Inst. Phys. /CERN /Geneva U. /Copenhagen U. /City Coll., N.Y. /Wisconsin U., Madison /Rio de Janeiro Federal U. /Wisconsin U., Madison /Stockholm U. /University Coll. London

2011-12-08

57

Differential scanning calorimetry of coal  

NASA Technical Reports Server (NTRS)

Differential scanning calorimetry studies performed during the first year of this project demonstrated the occurrence of exothermic reactions associated with the production of volatile matter in or near the plastic region. The temperature and magnitude of the exothermic peak were observed to be strongly affected by the heating rate, sample mass and, to a lesser extent, by sample particle size. Thermal properties also were found to be influenced by oxidation of the coal sample due to weathering effects.

Gold, P. I.

1978-01-01

58

Cdf II Integrated Calorimetry Environment  

NASA Astrophysics Data System (ADS)

The Run IIa integrated calorimetry environment of CDF II comprises: sampling scintillator calorimeters, e.m. pre-shower 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 pre-existing 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 in the central hadron, has now been extended the plug hadron calorimeter. To complete the integration in Run IIb (>2004), the central gas pre-shower will be replaced with a tile-fiber detector and the time information will be added also to the e.m. calorimeters. Select jet energy topics are described which show how the CDF II calorimetry has the capability to improve the measurement of the W and the top-quark masses, and to enhance the search for dijet mass peaks in conjunction with b-tagging.

Dell'Agnello, S.

2002-01-01

59

Use of DSC to detect the heterogeneity of hydrothermal stability in the polyphenol-treated collagen matrix.  

PubMed

The hydrothermal stability of the collagen matrixes treated with plant polyphenols (tannins) depends on not only the strength of the polyphenol-collagen interactions but also the distribution uniformity of polyphenolic molecules within the collagen fibrils. Traditional methods of uniformity tests rely heavily on the expertise of workers and are thus subjective. This paper describes a differential scanning calorimetry (DSC) study of the sheepskin collagen samples treated with hydrolyzable tannins, including two commercial tannins' extracts (chestnut and valonea), two pure ellagitannins (vescalagin and castalagin), and six synthetic gallotannins (di-galloyl-ethylene glycol (DGE), tri-galloyl-glycerol, tetra-galloyl-meso-erythritol, penta-galloyl-adonitol, penta-galloyl-glucose, and hexa-galloyl-ducitol). The collagen sample without polyphenol treatment and the sample treated with DGE showed a single sharp peak in their DSC thermogram with a full peak width at half height (fwhh) of 3-4 degrees C. The samples treated with other tannins all showed multiple peak DSC profiles with the fwhh of each peak at about 3-4 degrees C. These multiple peak profiles imply that in these polyphenol-treated samples, there is a distribution of collagen molecules having different hydrothermal stability. The results have demonstrated that DSC offers an objective method to detect the stability heterogeneity of collagen matrixes in the solid state, providing a useful tool for the leather industry to evaluate the uniformity of leather tanning. PMID:14582955

Tang, H R; Covington, A D; Hancock, R A

2003-11-01

60

Determination of kinetics parameters of glass transition in glassy Se and glassy Se98M2 alloys using DSC technique  

NASA Astrophysics Data System (ADS)

Glassy Se and Se98M2 (M = Ag, Cd, Zn) alloys are obtained by the melt quenching technique. Differential Scanning Calorimetry (DSC) technique (under non-isothermal conditions) has been applied to see the effects of Ag, Cd, and Zn additives on the glass transition kinetics of Se-rich glassy alloys at different heating rates. The variation of glass transition temperature, T g with the heating rate, ? has been used to investigate the glass transition kinetics. The values of various kinetic parameters such as glass transition temperature, activation energy of glass transition, overall mean bond energy < E>, heat of atomization H S , bond strength (Se-M) have also been calculated.

Dohare, C.; Mehta, N.

2014-02-01

61

Hyperspectral image lossless compression using DSC and 2-D CALIC  

Microsoft Academic Search

In recent few years, DSC (Distributed Source Coding) technology is catched much attentions in remote sensing image compression field,due to its excellent performance and low encoding complexity. In this paper, we propose a DSC-based practical solution for hyperspectral image lossless compression system, which applies the DSC technique using the power channel codes of Low-Density-Parity-Check Accumulated(LDPCA) codes and incorporates an efficient

Xueping Yan; Jiaji Wu

2010-01-01

62

Impedance Spectroscopy and DSC Studies of Poly(vinyl Alcohol)/silicotungstic Acid Crosslinked Composite Membranes  

NASA Astrophysics Data System (ADS)

Chemically crosslinked composite membranes consisting of poly(vinyl alcohol) (PVA) and silicotungstic acid (STA) have been prepared by solution casting method and evaluated as proton conducting polymer electrolytes. The proton conductivity of the membranes were investigated as a function of blending composition, crosslinking density and temperature. The conductivity mechanism was investigated by using Impedance spectroscopy in the region between 40 Hz and 10 MHz. Membranes were also characterized by FTIR spectroscopy to confirm the crosslinking reaction and differential scanning calorimetry (DSC) to assess the thermal stability. Membrane swelling decreased with increase in crosslinking density accompanied by improvement in mechanical properties. The proton conductivity of the membranes were of the order of 10-3 S/cm and showed similar resistance to methanol permeability than Nafion 112 under the same measurement conditions.

Anis, Arfat; Banthia, A. K.

2006-06-01

63

Differential scanning calorimetry to investigate the compatibility of ciprofloxacin hydrochloride with excipients.  

PubMed

The compatibility between ciprofloxacin hydrochloride (CFX) and some excipients was evaluated using differential scanning calorimetry (DSC). Physical mixture, coground mixture, compressed mixture and kneaded mixture were prepared to study the effect of sample manipulation. In addition, the samples of physical mixture were also accelerated at 55 degrees C for three weeks to obtain more reliable conclusions. Different types of excipients currently used in tablet or capsule formulations namely, calcium phosphate dibasic dihydrate (Emcompress), magnesium stearate lactose, sorbitol, mannitol, croscarmellose sodium (Ac-Di-Sol), sodium carboxymethyl starch (Primojel), microcrystalline cellulose (Avicel PH 101, Emcocil) were examined. The DSC scan of CFX displayed two endothermic peaks probably as a result of a fusion process followed by a decomposition process. CFX appeared to interact with sorbitol, mannitol, Ac-Di-Sol, Primojel, Avicel PH 101 and Emcocil. PMID:12561245

Fathy, M; Hassan, M A; Mohamed, F A

2002-12-01

64

Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyzer (TEGA)  

NASA Technical Reports Server (NTRS)

Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current C development and cutting edge research. The Thermal Evolved Gas Analyzer (MGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil.

Musselwhite, D. S.; Boynton, W. V.; Ming, Douglas W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

2000-01-01

65

Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyser (TEGA)  

NASA Technical Reports Server (NTRS)

Differential Scanning Calorimetry (DSC) combined with evolved gas analysis (EGA) is a well developed technique for the analysis of a wide variety of sample types with broad application in material and soil sciences. However, the use of the technique for samples under conditions of pressure and temperature as found on other planets is one of current development and cutting edge research. The Thermal Evolved Gas Analyzer (TEGA), which was designed, built and tested at the University of Arizona's Lunar and Planetary Lab (LPL), utilizes DSC/EGA. TEGA, which was sent to Mars on the ill-fated Mars Polar Lander, was to be the first application of DSC/EGA on the surface of Mars as well as the first direct measurement of the volatile-bearing mineralogy in martian soil. Additional information is available in the original extended abstract.

Musselwhite, D. S.; Boynton, W. V.; Ming, D. W.; Quadlander, G.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

2000-01-01

66

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 4: Estudo de Caso -DSC * Pg. 1  

E-print Network

de iniciação científica LSD - Laboratório de Sistemas Distribuídos, de uso específico dos Firewall DSC Server 1 UNIX Server 2 UNIX Server 1 Windows LabCom LSD LEPRECOM LSI LabPetri LAD LIA Miniblio ao setor (no caso do LSD, LEPRECOM, LSI, LIA e LabPetri). ! Os setores (nuvens) em amarelo, usam

Cirne, Walfredo

67

Deconvolution Analysis for Classifying Gastric Adenocarcinoma Patients Based on Differential Scanning Calorimetry Serum Thermograms  

PubMed Central

Recently, differential scanning calorimetry (DSC) has been acknowledged as a novel tool for diagnosing and monitoring several diseases. This highly sensitive technique has been traditionally used to study thermally induced protein folding/unfolding transitions. In previous research papers, DSC profiles from blood samples of patients were analyzed and they exhibited marked differences in the thermal denaturation profile. Thus, we investigated the use of this novel technology in blood serum samples from 25 healthy subjects and 30 patients with gastric adenocarcinoma (GAC) at different stages of tumor development with a new multiparametric approach. The analysis of the calorimetric profiles of blood serum from GAC patients allowed us to discriminate three stages of cancer development (I to III) from those of healthy individuals. After a multiparametric analysis, a classification of blood serum DSC parameters from patients with GAC is proposed. Certain parameters exhibited significant differences (P < 0.05) and allowed the discrimination of healthy subjects/patients from patients at different tumor stages. The results of this work validate DSC as a novel technique for GAC patient classification and staging, and offer new graphical tools and value ranges for the acquired parameters in order to discriminate healthy from diseased subjects with increased disease burden. PMID:25614381

Vega, Sonia; Garcia-Gonzalez, María Asuncion; Lanas, Angel; Velazquez-Campoy, Adrian; Abian, Olga

2015-01-01

68

Deconvolution analysis for classifying gastric adenocarcinoma patients based on differential scanning calorimetry serum thermograms.  

PubMed

Recently, differential scanning calorimetry (DSC) has been acknowledged as a novel tool for diagnosing and monitoring several diseases. This highly sensitive technique has been traditionally used to study thermally induced protein folding/unfolding transitions. In previous research papers, DSC profiles from blood samples of patients were analyzed and they exhibited marked differences in the thermal denaturation profile. Thus, we investigated the use of this novel technology in blood serum samples from 25 healthy subjects and 30 patients with gastric adenocarcinoma (GAC) at different stages of tumor development with a new multiparametric approach. The analysis of the calorimetric profiles of blood serum from GAC patients allowed us to discriminate three stages of cancer development (I to III) from those of healthy individuals. After a multiparametric analysis, a classification of blood serum DSC parameters from patients with GAC is proposed. Certain parameters exhibited significant differences (P < 0.05) and allowed the discrimination of healthy subjects/patients from patients at different tumor stages. The results of this work validate DSC as a novel technique for GAC patient classification and staging, and offer new graphical tools and value ranges for the acquired parameters in order to discriminate healthy from diseased subjects with increased disease burden. PMID:25614381

Vega, Sonia; Garcia-Gonzalez, María Asuncion; Lanas, Angel; Velazquez-Campoy, Adrian; Abian, Olga

2015-01-01

69

Ultrasonic spectroscopy and differential scanning calorimetry of liposomal-encapsulated nisin.  

PubMed

The thermal stability of phosphatidylcholine (PC) liposomes (colloidal dispersions of bilayer-forming polar lipids in aqueous solvents) in the presence and absence of the antimicrobial polypeptide nisin was evaluated using differential scanning calorimetry (DSC) and low-intensity ultrasonic spectroscopy (US). PC liposome mixtures with varying acyl chain lengths (C16:0 and C18:0) were formed in buffer with or without entrapped nisin. Gel-to-liquid crystalline phase transition temperatures (T(M)) of liposomes determined from DSC thermograms were in excellent agreement with those determined by ultrasonic velocity and attenuation coefficient measurements recorded at 5 MHz. The dipalmitoylphosphatidylcholine (DPPC) T(M) measured by DSC was approximately 41.3 and approximately 40.7 degrees C when measured by ultrasonic spectroscopy. The T(M) of distearoylphosphatidylcholine (DSPC) and DPPC/DSPC 1:1 liposomes was 54.3 and 54.9 degrees C and approximately 44.8 and approximately 47.3 degrees C when measured by DSC and US, respectively. The thermotropic stability generally increased upon addition of nisin. Analysis of the stepwise decrease in ultrasonic velocity with temperature indicated an increased compressibility corresponding to a loss of structure upon heating. PMID:16248577

Taylor, T Matthew; Davidson, P Michael; Bruce, Barry D; Weiss, Jochen

2005-11-01

70

Ionic liquids: differential scanning calorimetry as a new indirect method for determination of vaporization enthalpies.  

PubMed

Differential scanning calorimetry (DSC) has been used to measure enthalpies of synthesis reactions of the 1-alkyl-3-methylimidazolium bromide [C(n)mim][Br] ionic liquids from 1-methylimidazole and n-alkyl bromides (with n = 4, 5, 6, 7, and 8). The optimal experimental conditions have been elaborated. Enthalpies of formation of these ionic liquids in the liquid state have been determined using the DSC results according to the Hess Law. The ideal-gas enthalpies of formation of [C(n)mim][Br] were calculated using the methods of quantum chemistry. They were used together with the DSC results to derive indirectly the enthalpies of vaporization of the ionic liquids under study. In order to validate the indirect determination, the experimental vaporization enthalpy of [C(4)mim][Br] was measured by using a quartz crystal microbalance (QCM). The combination of reaction enthalpy measurements by DSC with modern high-level first-principles calculations opens valuable indirect thermochemical options to obtain values of vaporization enthalpies of ionic liquids. PMID:22435356

Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph

2012-04-12

71

Dijet mass resolution and compensating calorimetry  

SciTech Connect

The calorimetry for SSC detectors has as its role the detection of the basic particles of the Standard Model. Those germane to calorimetry are quarks, photons, electrons, and gluons. Note that all the hadronic entities appear in the calorimetry as jets. The detection of single hadrons belongs to a past era when quark molecules'' were the focus of intense study. Thus, the goal of calorimetry at the SSC must be the study of jets. In particular, one must understand what defines the limits of accuracy of the jets. If there are intrinsic physical processes which limit the precision of jet measurements, then calorimetry which is more accurate is unnecessary if not wasteful. 5 refs., 5 figs.

Green, D.

1991-05-01

72

Multivariate statistical analysis treatment of DSC thermal properties for animal fat adulteration.  

PubMed

The adulteration of edible fats is a kind of fraud that impairs the physical and chemical features of the original lipid materials. It has been detected in various food, pharmaceutical and cosmeceutical products. Differential scanning calorimetry (DSC) is the robust thermo-analytical machine that permits to fingerprint the primary crystallisation of triacylglycerols (TAGs) molecules and their transition behaviours. The aims of this study was to assess the cross-contamination caused by lard concentration of 0.5-5% in the mixture systems containing beef tallow (BT) and chicken fat (CF) separately. TAGs species of pure and adulterated lipids in relation to their crystallisation and melting parameters were studied using principal components analysis (PCA). The results showed that by using the heating profiles the discrimination of LD from BT and CF was very clear even at low dose of less than 1%. Same observation was depicted from the crystallisation profiles of BT adulterated by LD doses ranging from 0.1% to 1% and from 2% to 5%, respectively. Furthermore, CF adulterated with LD did not exhibit clear changes on its crystallisation profiles. Consequently, DSC coupled with PCA is one of the techniques that might use to monitor and differentiate the minimum adulteration levels caused by LD in different animal fats. PMID:24731324

Dahimi, Omar; Rahim, Alina Abdul; Abdulkarim, S M; Hassan, Mohd Sukri; Hashari, Shazamawati B T Zam; Mashitoh, A Siti; Saadi, Sami

2014-09-01

73

Interactions of tamoxifen with distearoyl phosphatidylcholine multilamellar vesicles: FTIR and DSC studies.  

PubMed

Interactions of a non-steroidal antiestrogen drug, tamoxifen (TAM), with distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) multilamellar liposomes (MLVs) were investigated as a function of drug concentration (1-15 mol%) by using two noninvasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy results show that increasing TAM concentrations (except 1 mol%) increased the wavenumbers of the CH2 stretching modes, implying an disordering effect for DSPC MLVs both in the gel and liquid crystalline phases. The bandwidth values of the CH2 stretchings except for 1 mol% increased when TAM concentrations increased for DSPC liposomes, indicating an increase in the dynamics of liposomes. The CO stretching and PO2- antisymmetric double bond stretching bands were analyzed to study interactions of TAM with head groups of lipids. As the concentrations of TAM increased, dehydration occurred around these functional groups in the polar part of the lipids. The DSC studies on thermal properties of DSPC lipids indicate that TAM eliminated the pre transition, shifted the main phase transition to lower temperatures and broadened the phase transition curve of the liposomes. PMID:24792199

Bilge, Duygu; Sahin, Ipek; Kazanci, Nadide; Severcan, Feride

2014-09-15

74

Interactions of tamoxifen with distearoyl phosphatidylcholine multilamellar vesicles: FTIR and DSC studies  

NASA Astrophysics Data System (ADS)

Interactions of a non-steroidal antiestrogen drug, tamoxifen (TAM), with distearoyl-sn-glycero-3-phosphatidylcholine (DSPC) multilamellar liposomes (MLVs) were investigated as a function of drug concentration (1-15 mol%) by using two noninvasive techniques, namely Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). FTIR spectroscopy results show that increasing TAM concentrations (except 1 mol%) increased the wavenumbers of the CH2 stretching modes, implying an disordering effect for DSPC MLVs both in the gel and liquid crystalline phases. The bandwidth values of the CH2 stretchings except for 1 mol% increased when TAM concentrations increased for DSPC liposomes, indicating an increase in the dynamics of liposomes. The Cdbnd O stretching and PO2- antisymmetric double bond stretching bands were analyzed to study interactions of TAM with head groups of lipids. As the concentrations of TAM increased, dehydration occurred around these functional groups in the polar part of the lipids. The DSC studies on thermal properties of DSPC lipids indicate that TAM eliminated the pre transition, shifted the main phase transition to lower temperatures and broadened the phase transition curve of the liposomes.

Bilge, Duygu; Sahin, Ipek; Kazanci, Nadide; Severcan, Feride

2014-09-01

75

SAXS/WAXS/DSC Study of Temperature Evolution in Nanopolymer Electrolyte  

E-print Network

Electrolytes as nanostructured materials are very attractive for batteries or other types of electronic devices. (PEO)8ZnCl2 polymer electrolytes and nanocomposites (PEO)8ZnCl2/TiO2 were prepared from PEO and ZnCl2 and with addition of TiO2 nanograins. The influence of TiO2 nanograins was studied by small-angle X-ray scattering (SAXS) simultaneously recorded with wide-angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) at the synchrotron ELETTRA. It was shown by previous impedance spectroscopy (IS) that the room temperature conductivity of nanocomposite polymer electrolyte increased more than two times above 65oC, relative to pure composites of PEO and salts. The SAXS/DSC measurements yielded insight into the temperature-dependent changes of the grains of the electrolyte as well as to differences due to different heating and cooling rates. The crystal structure and temperatures of melting and crystallization of the nanosize grains was revealed by the simultaneous WAXS measurements.

Aleksandra Turkovic; Mario Rakic; Pavo Dubcek; Magdy Lucic-Lavcevic; Sigrid Bernstorff

2008-09-03

76

Molecular characterization of DSC1 orthologs in invertebrate species.  

PubMed

DSC1 and BSC1 are two founding members of a novel family of invertebrate voltage-gated cation channels with close structural and evolutionary relationships to voltage-gated sodium and calcium channels. In this study, we searched the published genome sequences for DSC1 orthologs. DSC1 orthologs were found in all 48 insect species, and in other invertebrate species belonging to phyla Mollusca, Cnidaria, Hemichordata and Echinodermata. However, DSC1 orthologs were not found in four arachnid species, Ixodes scapularis, Rhipicephalus microplus, Tetranychus urticae and Varroa destructor, two species in Annelida or any vertebrate species. We then cloned and sequenced NlSC1 and BmSC1 full-length cDNAs from the brown planthopper (Nilaparvata lugens) and the silkworm (Bombyx mori), respectively. NlSC1 and BmSC1 share about 50% identity with DSC1, and the expression of NlSC1 and BmSC1 transcripts was most abundant in the head and antenna in adults. All DSC1 orthologs contain a unique and conserved DEEA motif, instead of the EEEE or EEDD motif in classical calcium channels or the DEKA motif in sodium channels. Phylogenetic analyses revealed that DSC1 and its orthologs form a separate group distinct from the classical voltage-gated sodium and calcium channels and constitute a unique family of cation channels. The DSC1/BSC1-family channels could be potential targets of new and safe insecticides for pest control. PMID:22321571

Cui, Ying-Jun; Yu, Lin-Lin; Xu, Hai-Jun; Dong, Ke; Zhang, Chuan-Xi

2012-05-01

77

Characterization of acidic properties of microporous and mesoporous zeolite catalysts using TGA and DSC  

SciTech Connect

Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied for characterizing the acidic properties of microporous and mesoporous zeolite catalysts through temperature-programmed desorption (TPD) of n-butylamine (n-BA). A flow system was designed with heating and evacuation capability for preparing the n-BA adsorbed sample. The sample was then transferred to TGA (or DSC) apparatus. n-BA desorption conducted on TGA at different temperatures represents the interaction with surface acidic sites of different strength. BAse desorption at 100-240{degrees}C, 240-340{degrees}C, and 340-500{degrees}C, was classified as weak, intramediate, and strong acid sites, respectively. DSC indicates the endothermic nature of the differential thermogravimetric peaks (observed from TGA) in the above temperature regimes, confirming the TPD data. The microporous zeolites examined include three proton-form mordenites, three proton-form and metal-ion exchanged Y-zeolites, and four noble metal catalysts supported on mordenite and Y-zeolite. Four mesoporous zeolites were synthesized and examined by the same TPD method. Both the total acidity (mmol/g) and acid strength distribution depend on the zeolite type. Si/Al ratio, and metal loading. Ni and La ion-exchange decreased the strong acid sites. Pt and Pd loading on an HY decreased the strong acid sites but their loading on an H-mordenite had little effect on its strong acid sites. Mesoporous zeolites showed lower acidity and lower fraction of strong acid sites compared to HY and H-mordenites. However, the acidity of mesoporous zeolites strongly depends on the aluminum source compounds used in the hydrothermal synthesis of the zeolites.

Song, Chunshan; Lai, Wei-Chuan; Schmitz, A.D.; Reddy, K.M. [Pennsylvania State Univ., University Park, PA (United States)] [and others

1996-10-01

78

Calibration of Chemical Kinetic Models Using Simulations of Small-Scale Cookoff Experiments  

SciTech Connect

Establishing safe handling limits for explosives in elevated temperature environments is a difficult problem that often requires extensive simulation. The largest influence on predicting thermal cookoff safety lies in the chemical kinetic model used in these simulations, and these kinetic model reaction sequences often contain multiple steps. Several small-scale cookoff experiments, notably Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), One-Dimensional Time-to-Explosion (ODTX), and the Scaled Thermal Explosion (STEX) have been performed on various explosives to aid in cookoff behavior determination. Past work has used a single test from this group to create a cookoff model, which does not guarantee agreement with the other experiments. In this study, we update the kinetic parameters of an existing model for the common explosive 2,4,6-Trinitrotoluene (TNT) using DSC and ODTX experimental data at the same time by minimizing a global Figure of Merit based on hydrodynamic simulated data. We then show that the new kinetic model maintains STEX agreement, reduces DSC agreement, and improves ODTX and TGA agreement when compared to the original model. In addition, we describe a means to use implicit hydrodynamic simulations of DSC experiments to develop a reaction model for TNT melting.

Wemhoff, A P; Becker, R C; Burnham, A K

2008-02-26

79

Study on the melting and freezing behaviour of high temperature binary eutectic fixed points using differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

We have measured the heat flux accompanying the melting or freezing of metal (or metalloid)-carbon eutectics, using differential scanning calorimetry (DSC) to identify appropriate binary systems for secondary thermometry fixed points. Well-known alloy systems such as Fe-C and Ni-C showed reproducible endothermic and exothermic peaks that represent melting and freezing reactions in the DSC measurement. Furthermore, a new Si-C system with a eutectic composition showed reproducible melting and freezing peaks in the DSC measurements. Based on the results by DSC, we identified the Si-SiC eutectic point as a possible eutectic fixed point. To confirm this possibility, we made a Si-SiC cell for thermocouple thermometry and measured its melting and freezing characteristics using a Pt/Pd thermocouple. The melting temperature of the Si-SiC eutectic was reproducible to within 0.02 °C (one standard deviation). From the results, we found that Si-SiC has possibility as a new eutectic fixed point at temperatures around 1400 °C. We also concluded that DSC analysis could be used to measure the reproducibility of freezing and melting reactions that are to be used as fixed points for thermometry, because it is a rapid and easy-to-use tool for characterizing the thermal behaviour of materials with only a small sample.

Kwon, Su Yong; Kim, Yong-Gyoo; Yang, Inseok

2010-06-01

80

Application of differential scanning calorimetry in evaluation of solid state interactions in tablets containing acetaminophen.  

PubMed

Differential scanning calorimetry (DSC) is an analytical procedure used to determine the differences in the heat flow generated or absorbed by the sample. This method allows to assess purity and polymorphic form of drug compounds, to detect interactions between ingredients of solid dosage forms and to analyze stability of solid formulations. The aim of this study was the assessment of compatibility between acetaminophen (API) and different types of excipients often used in tablets compression: polyvinylpyrrolidone, crospovidone, pregelatinized starch, microcrystalline cellulose and magnesium stearate by differential scanning calorimetry. The study contains results of thermal analysis of excipients and individually performed mixtures of these substances with acetaminophen before and after compression and after 6 months storage of tablets at different temperature and relative humidity conditions (25 +/- 2 degrees C /40 +/- 5% RH, 25 +/- 2 degrees C /60 +/- 5% RH, 40 +/- 2 degrees C /75 +/- 5% RH) for a period of 6 months. To detect possible changes of API chemical structure, gas chromatography-mass spectrometry (GC-MS) was also applied. GC-MS with electron impact ionization (EI) was employed to determine the fragmentation pattern of API. It was shown that the developed formulations showed excellent compatibility among all excipients used except Kollidon CL. The interaction with Kollidon CL is probably a result of a physical reaction as confirmed by GC-MS analyses. Obtained results revealed that DSC can be successfully applied to evaluate possible incompatibilities between acetaminophen and Kollidon. PMID:24147356

Mazurek-Wado?kowska, Edyta; Winnicka, Katarzyna; Czajkowska-Ko?nik, Anna; Czyzewska, Urszula; Miltyk, Wojciech

2013-01-01

81

Thermal properties of cowpea flour: a study by differential scanning calorimetry.  

PubMed

The thermal properties of 12 varieties of cowpea flour were studied by differential scanning calorimetry (DSC). Flour samples were prepared to a paste of 60% moisture content and sealed in standard DSC pans. Samples were scanned at a heating rate of 5 degrees C/min over a scan range of 40- 130 degrees C. Samples exhibited single major endotherms, which occurred over varied temperatures. The transition enthalpy (deltaH) ranged between 1.4 J/g and 4.7 J/g. Transition onset (T(o)) and transition peak (T(p)) temperatures ranged between 75-78 degrees C and 78-82 degrees C,respectively. All the DSC parameters measured varied significantly among the varieties. The transition enthalpy (deltaH) was the most discriminating parameter and accounted for 80% of the total variance. The major chemical components of cowpea flour, starch amylose and protein are significant predictors of deltaH. Protein denaturation appears to be a significant modification which occurs during processing of cowpea seeds to flour. The transition enthalpy deltaH could become an important functional index of cowpea flour when related to some quality parameters in products that contain the flour. PMID:12866616

Henshaw, Folake O; McWatters, Kay H; Akingbala, John O; Chinnan, Manjeet S

2003-06-01

82

Effect of urea on phase transition of poly(N-isopropylacrylamide) investigated by differential scanning calorimetry.  

PubMed

The effect of urea on the phase transition of PNIPAM was studied using differential scanning calorimetry (DSC). For a certain urea concentration, the enthalpy change of phase transition of poly(N-isopropylacrylamide) (PNIPAM) aqueous solution increases with the number of DSC cycles, presumably due to the displacement of water molecules bound to the amide groups of PNIPAM by urea molecules at the temperature higher than the lower critical solution temperature (LCST) of PNIPAM and causes the decrease in the absolute value of the exothermic heat related to the dehydration of hydrophilic groups and interactions of hydrophilic residues to around 0. Moreover, the enthalpy change decreases with the urea concentration during the heating process of the first DSC cycle, indicating the replacement of water molecules around the apolar isopropyl groups by urea molecules at the temperature lower than LCST, and the endothermic heat caused by the dehydration of apolar groups decreases. Furthermore, the urea molecules which replace the water molecules at high temperature can be replaced again by water molecules at the temperature lower than LCST, but this process needs several days to complete. PMID:25029067

Gao, Yating; Yang, Jinxian; Ding, Yanwei; Ye, Xiaodong

2014-08-01

83

Differential Scanning Calorimetry and Evolved Gas Analysis at Mars Ambient Conditions Using the Thermal Evolved Gas Analyser (TEGA)  

NASA Technical Reports Server (NTRS)

We are conducting DSC/EGA experiments at Mars ambient temperature and pressure using the TEGA engineering model. These tests illustrate the outstanding capabilities of a TEGA-like instrument on the surface of Mars.

Musselwhite, D. S.; Boynton, W. V.; Ming, D. W.; Quadlander, G. A.; Kerry, K. E.; Bode, R. C.; Bailey, S. H.; Ward, M. G.; Pathare, A. V.; Lorenz, R. D.

2000-01-01

84

Using direct calorimetry to test the accuracy of indirect calorimetry in an ectotherm.  

PubMed

We previously demonstrated that the relationship between respiratory gas exchange and metabolic heat production is unexpectedly variable and that conventional approaches to estimating energy expenditure by indirect calorimetry can incorporate large errors. Prior studies, however, comparing direct and indirect calorimetry of animals focused only on endothermic organisms. Given that endothermy and ectothermy represent a fundamental dichotomy of animal energetics, in this analysis we explore how these contrasting physiologies correlate with the relationship between heat production and respiratory gas exchange. Simultaneous indirect and direct calorimetry in an ectotherm, the ball python (Python regius Shaw), revealed that the relationships between gas exchange and heat production were within 1% of those expected when analyses using indirect calorimetry were based on the assumption that the fasting animal catabolized only protein. This accuracy of indirect calorimetry contrasts sharply with our previous conclusions for three species of birds and mammals. PMID:16826509

Walsberg, Glenn E; Hoffman, Ty C M

2006-01-01

85

Starch gelatinization and amylose–lipid interactions during rice parboiling investigated by temperature resolved wide angle X-ray scattering and differential scanning calorimetry  

Microsoft Academic Search

Starch gelatinization and formation of crystalline amylose–lipid complexes during the heat\\/moisture treatment step in rice parboiling were studied with temperature resolved wide angle X-ray scattering (WAXS) and differential scanning calorimetry (DSC) using flour from Puntal (24% apparent amylose) and Jacinto (12% apparent amylose) rice samples [66, 40 or 25% moisture content (mc)]. Temperature resolved WAXS showed that the crystallinity index

V. Derycke; G. E. Vandeputte; R. Vermeylen; W. De Man; B. Goderis; M. H. J. Koch; J. A. Delcour

2005-01-01

86

Characterization of acidic properties of microporous and mesoporous zeolite catalysts using TGA and DSC  

SciTech Connect

Thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC) were applied for characterizing the acidic properties of microporous and mesoporous zeolite catalysts through temperature-programmed desorption (TPD) of n-butylamine (n-BA) as a base probe molecule. A flow system was designed with heating and evacuation capability for preparing the n-BA adsorbed sample. In the TGA, n-BA desorption at different temperatures represents the interaction with surface acidic sites of different strength. The acid sites corresponding to base desorption at 100-240{degrees}C, 240-340{degrees}C, and 340-500{degrees}C, were classified as weak, intermediate, and strong acid sites, respectively. DSC indicates the endothermic nature of the differential thermogravimetric peaks (observed from TGA) in the above temperature regimes, consuming the TPD data. The microporous zeolites examined include three proton-form mordenites, three proton-form and metal-ion exchanged Y-zeolites, and four noble metal catalysts supported on mordenite and Y-zeolite. Four mesoporous zeolites were synthesized and examined by the same TPD method. Both the total acidity (mmol/g) and acid strength distribution depend on the zeolite VAX, Si/Al ratio, and metal loading. Ni and La ion-exchange decreased the strong acid sites. Pt and Pd loading on an HY decreased the strong acid sites but their loading on an H-mordenite had little effect on its strong acid sites. Mesoporous zeolites showed lower acidity and lower fraction of strong acid sites compared to HY and H-mordenites. However, the acidity of mesoporous zeolites strongly depends on the aluminum source compounds used in the hydrothermal synthesis of the zeolites.

Song, Chunshan; Lai, Wei-Chuan; Schmitz, A.D. [Pennsylvania State Univ., University Park, PA (United States)] [and others

1996-12-31

87

A sample-saving method for heat capacity measurements on powders using relaxation calorimetry  

PubMed Central

An experimental method is described for determining the low-temperature heat capacity (Cp) of mg-sized powder samples using the Quantum Design “Physical Properties Measurement System” (PPMS). The powder is contained in an Al pan as an ?1 mm thick compressed layer. The sample is not mixed with Apiezon N grease, as compared to other methods. Thus, it is not contaminated and can be used for further study. This is necessary for samples that are only available in tiny amounts. To demonstrate the method various samples, all insulating in nature, were studied including benzoic acid, sapphire and different silicate minerals. The measurements show that the method has an accuracy in Cp to better than 1% at T above 30–50 K and ±3–5% up to ±10% below. The experimental procedure is based on three independent PPMS and three independent differential scanning calorimetry (DSC) measurements. The DSC Cp data are used to slightly adjust the PPMS Cp data by a factor CpDSC/CpPPMSat298K. This is done because heat capacities measured with a DSC device are more accurate around ambient T (?0.6%) than PPMS values and is possible because the deviation of PPMS heat capacities from reference values is nearly constant between about 50 K and 300 K. The resulting standard entropies agree with published reference values within 0.21% for the silicates, by 0.34% for corundum, and by 0.9% for powdered benzoic acid. The method thus allows entropy determinations on powders with an accuracy of better than 1%. The advantage of our method compared to other experimental techniques is that the sample powder is not contaminated with grease and that heat capacity values show less scatter at high temperatures. PMID:21886915

Dachs, Edgar; Benisek, Artur

2011-01-01

88

Liquid Argon Calorimetry for ATLAS  

NASA Astrophysics Data System (ADS)

This summer, the largest collaborative physics project since the Manhattan project will go online. One of four experiments for the Large Hadron Collider at CERN in Geneva, ATLAS, employs over 2000 people. Canadians have helped design, construct, and calibrate the liquid argon calorimeters for ATLAS to capture the products of the high energy collisions produced by the LHC. From an undergraduate's perspective, explore how these calorimeters are made to handle their harsh requirement. From nearly a billion proton-proton collisions a second, physicists hope to discover the Higgs boson and other new fundamental particles.

Robinson, Alan

2008-05-01

89

Calorimetry of the Rice Detector  

NASA Astrophysics Data System (ADS)

Radio Ice Cherenkov Experiment (RICE) is an ultrahigh-energy (UHE) cosmic ray neutrino detector for neutrino energies greater than a PeV. This pilot project explores the radio detection technique for UHE particles. Deployed at the Antarctic polar ice cap, RICE antennas have been operational since 1996. Basic calibrations of the antenna array have been done using data taken mostly in situ. The calibration results and an upper limit on electron neutrino flux based on one month of analyzed data are reported here.

Razzaque, Soebur

2002-01-01

90

Glass transition and crystallization kinetics of CsLiB 6O 10 glasses by differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

Transparent glasses of CsLiB 6O 10 (CLBO) were fabricated via the conventional melt-quenching technique. The amorphous and the glassy characteristics of the as-quenched samples were, respectively, established by X-ray powder diffraction (XRD) and differential scanning calorimetry (DSC). To evaluate the activation energies for the glass transition and crystallization of these glasses, DSC runs were made at different heating rates. The value of the Avrami exponent, n, was found to be 3.5±0.3, suggesting a mixed transformation mechanism (two- and three-dimensional crystal growth). The average values of the activation energies associated with the glass transition and crystallization of CLBO glasses were 670±4 and 341±7 kJ/mol, respectively. Values of the kinetics parameters obtained using isothermal and non-isothermal techniques were in excellent agreement.

Vaish, Rahul; Varma, K. B. R.

2007-09-01

91

Apparent Thermal Properties of Phase-Change Materials: An Analysis Using Differential Scanning Calorimetry and Impulse Method  

NASA Astrophysics Data System (ADS)

Thermal properties of newly developed plaster based on hydrated lime, metakaolin, and paraffinic wax enclosed in polymer micro-capsules are studied in the article. At first, differential scanning calorimetry (DSC) is applied on Micronal PCM capsules for determination of the temperature interval of thawing and solidification. Then, the initial temperature of the phase change and specific heat capacity of the plaster are measured by DSC. The thermal conductivity and thermal diffusivity are determined by an impulse method. For comparative reasons, the properties of lime-based plaster without PCM are studied as well. The obtained results demonstrate the enhanced heat storage capacity of the studied material that can be used for application in lightweight building envelope systems.

Pavlík, Zbyšek; Trník, Anton; Ondruška, Ján; Keppert, Martin; Pavlíková, Milena; Volfová, Petra; Kaulich, Viktor; ?erný, Robert

2013-05-01

92

One-step simultaneous differential scanning calorimetry-FTIR microspectroscopy to quickly detect continuous pathways in the solid-state glucose/asparagine Maillard reaction.  

PubMed

The stepwise reaction pathway of the solid-state Maillard reaction between glucose (Glc) and asparagine (Asn) was investigated using simultaneous differential scanning calorimetry (DSC)-FTIR microspectroscopy. The color change and FTIR spectra of Glc-Asn physical mixtures (molar ratio = 1:1) preheated to different temperatures followed by cooling were also examined. The successive reaction products such as Schiff base intermediate, Amadori product, and decarboxylated Amadori product in the solid-state Glc-Asn Maillard reaction were first simultaneously evidenced by this unique DSC-FTIR microspectroscopy. The color changed from white to yellow-brown to dark brown, and appearance of new IR peaks confirmed the formation of Maillard reaction products. The present study clearly indicates that this unique DSC-FTIR technique not only accelerates but also detects precursors and products of the Maillard reaction in real time. PMID:24645515

Hwang, Deng-Fwu; Hsieh, Tzu-Feng; Lin, Shan-Yang

2013-01-01

93

Benzanilide: on the crossroads of calorimetry, computations and concepts  

NASA Astrophysics Data System (ADS)

The standard (p° = 0.1 MPa) molar enthalpy of formation for solid benzanilide was derived from the standard molar enthalpy of combustion, in oxygen, at T = 298.15 K, measured by static bomb combustion calorimetry, and the standard molar enthalpy of sublimation, at T = 298.15 K, measured by Calvet microcalorimetry. From these experiments the standard molar enthalpy of formation of benzanilide in the gaseous phase at T = 298.15 K was calculated. In addition density functional theory calculations with the B3LYP functional and a variety of basis sets have been performed for benzanilide and some auxiliary molecules.

Matos, M. A. R.; Miranda, M. S.; Morais, V. M. F.; Liebman, J. F.

94

Isothermal Titration Calorimetry in the Student Laboratory  

ERIC Educational Resources Information Center

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…

Wadso, Lars; Li, Yujing; Li, Xi

2011-01-01

95

Photopyroelectric calorimetry down to 10 K  

Microsoft Academic Search

In photopyroelectric calorimetry thermal conductivity, thermal diffusivity and specific heat are measured simultaneously from the same heating or cooling run. As it provides a good signal-to-noise ratio with small temperature gradients, it is well suited to study the critical behaviour of phase transitions. Up to now, it has been mainly used above 77 K. In this work we implement the

M. Massot; A. Oleaga; A. Salazar

2006-01-01

96

Liquid argon calorimetry for the SSC  

SciTech Connect

Liquid argon calorimetry is a mature technique. However, adapting it to the challenging environment of the SSC requires a large amount of R D. The advantages of the liquid argon approach are summarized and the issues being addressed by the R D program are described. 18 refs.

Gordon, H.A.

1990-01-01

97

Heater Lead Error in Calorimetry  

NASA Astrophysics Data System (ADS)

A summary of previous work is followed by an examination of the effects of radiation from heater leads. Solutions of the exact differential equation for particular experimental configurations have been obtained by a numerical method. For certain simple situations the solutions can be checked against partial or complete analytical solutions of the equation. It is shown that even for low temperature calorimeters a large part of the electrical energy dissipated in heater leads may be radiated unless the lead resistance is kept very low. If a significant part of the total energy supplied to the calorimeter is radiated, systematic errors may arise because, for a given calorimeter heating rate, the heater lead radiation loss will differ in the ``full'' and ``empty calorimeter'' experiments.

Martin, Douglas L.

1972-12-01

98

Study of the thermal behavior of choline ibuprofenate using differential scanning calorimetry and hot-stage microscopy  

NASA Astrophysics Data System (ADS)

The phase transformations in choline ibuprofenate, [chol][ibu], have been studied by differential scanning calorimetry (DSC) and hot-stage microscopy (HSM). Two crystalline forms, ? and ?, were identified that are very different in their thermal behavior, and thus probably very different in their crystal structures. The melting temperatures of the two crystal polymorphs differ as much as 50°. The higher temperature polymorph, ?, presents a sharp and fast crystallization process, while the melting transformation displays a very slow dynamics. The ? polymorph forms on cooling through a broad crystal-to-crystal transformation, and displays a melting process that is sharp compared with that of ? polymorph.

Diogo, Hermínio P.; Moura Ramos, Joaquim J.

2014-12-01

99

Detection of a new 'nematic-like' phase in liquid crystal-amphiphile mixture by differential scanning calorimetry  

SciTech Connect

Differential Scanning Calorimetry (DSC) studies on phase transitions of the pure liquid crystalline material N-4-methoxybenzylidene-4-butylaniline (MBBA) and mixtures of MBBA and the amphiphile Stearic Acid (StA) show significant changes in the behavior of mixture from pure MBBA, as regards the nematic-isotropic (N-I) transition temperature (T{sub c}) and other thermodynamic parameters like enthalpy, specific heat and activation energy with concentration of StA. In particular, the convexity of the Arrhenius plot in pure MBBA vanishes with StA concentration pointing to the formation of a new, perhaps 'nematic-like', phase in the mixtures.

Dan, Kaustabh, E-mail: kaustabhdan@gmail.com; Roy, Madhusudan, E-mail: kaustabhdan@gmail.com; Datta, Alokmay, E-mail: kaustabhdan@gmail.com [Surface Physics and Materials Science Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar Block, Sector 1, Kolkata-700064 (India)

2014-04-24

100

Detection of a new 'nematic-like' phase in liquid crystal-amphiphile mixture by differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

Differential Scanning Calorimetry (DSC) studies on phase transitions of the pure liquid crystalline material N-4-methoxybenzylidene-4-butylaniline (MBBA) and mixtures of MBBA and the amphiphile Stearic Acid (StA) show significant changes in the behavior of mixture from pure MBBA, as regards the nematic-isotropic (N-I) transition temperature (Tc) and other thermodynamic parameters like enthalpy, specific heat and activation energy with concentration of StA. In particular, the convexity of the Arrhenius plot in pure MBBA vanishes with StA concentration pointing to the formation of a new, perhaps 'nematic-like', phase in the mixtures.

Dan, Kaustabh; Roy, Madhusudan; Datta, Alokmay

2014-04-01

101

Biology Index Page DSC Home Page DESERT STUDIES CENTER  

E-print Network

Brown Pelican M* Page 1 of 7DSC Bird List 8/18/2007file://C:\\Documents and Settings\\Owner.YOUR-780C (Podicipedidae) Pied-billed Grebe Y Eared Grebe M Western Grebe M Pelicans (Pelecanidae) American White Pelican M

de Lijser, Peter

102

CDF (Collider Detector at Fermilab) calorimetry  

SciTech Connect

The Collider Detector at Fermilab (CDF) is a large detector built to study 2 TeV anti p p collisions at the Fermilab Tevatron. The calorimetry, which has polar angle coverage from 2 to 178, and complete azimuthal coverage within this region, forms the subject of this paper. It consists of both electromagnetic shower counters (EM calorimeters) and hadron calorimeters, and is segmented into about 5000 ''towers'' or solid angle elements.

Jensen, H.B.

1987-03-01

103

Mass fractal characteristics of wet sonogels as determined by small-angle x-ray scattering and differential scanning calorimetry  

SciTech Connect

Low density silica sonogels were prepared from acid sonohydrolysis of tetraethoxysilane. Wet gels were studied by small-angle x-ray scattering (SAXS) and differential scanning calorimetry (DSC). The DSC tests were carried out under a heating rate of 2 deg. C/min from -120 deg. C up to 30 deg. C. Aerogels were obtained by CO{sub 2} supercritical extraction and characterized by nitrogen adsorption and SAXS. The DSC thermogram displays two distinct endothermic peaks. The first, a broad peak extending from about -80 deg. C up to practically 0 deg. C, was associated to the melting of ice nanocrystals with a crystal size distribution with 'pore' diameter ranging from 1 or 2 nm up to about 60 nm, as estimated from Thomson's equation. The second, a sharp peak with onset temperature close to 0 deg. C, was attributed to the melting of macroscopic crystals. The DSC incremental 'nanopore' volume distribution is in reasonable agreement with the incremental pore volume distribution of the aerogel as determined from nitrogen adsorption. No macroporosity was detected by nitrogen adsorption, probably because the adsorption method applies stress on the sample during measurement, leading to a underestimation of pore volume, or because often positive curvature of the solid surface is in aerogels, making the nitrogen condensation more difficult. According to the SAXS results, the solid network of the wet gels behaves as a mass fractal structure with mass fractal dimension D=2.20{+-}0.01 in a characteristic length scale below {xi}=7.9{+-}0.1 nm. The mass fractal characteristics of the wet gels have also been probed from DSC data by means of an earlier applied modeling for generation of a mass fractal from the incremental ''pore'' volume distribution curves. The results are shown to be in interesting agreement with the results from SAXS.

Vollet, D. R.; Donatti, D. A.; Ibanez Ruiz, A.; Gatto, F. R. [Departamento de Fisica, Unesp-Univerisdade Estadual Paulista, IGCE, P.O. Box 178 CEP 13500-970 Rio Claro, SP (Brazil)

2006-07-01

104

Polymorphism of [Zn(NH 3) 4](ClO 4) 2 and [Zn(NH 3) 4](BF 4) 2 studied by differential scanning calorimetry and far infrared spectroscopy  

Microsoft Academic Search

The phase transitions in [Zn(NH3)4](ClO4)2 and [Zn(NH3)4](BF4)2 were determined by differential scanning calorimetry (DSC) and the discovered phases were identified by far infrared spectroscopy (FT-FIR). Four solid phases were found for both the compounds. The characteristic changes in the FT-FIR absorption spectra were observed in the particular phases of both the compounds at temperatures predicted by the DSC. Additionally, the

A. Migda?-Mikuli; E. Mikuli; ?. Hetma?czyk; E. ?ciesi?ska; J. ?ciesi?ski; S. Wróbel; N. Górska

2001-01-01

105

Dsc orthologs are required for hypoxia adaptation, triazole drug responses, and fungal virulence in Aspergillus fumigatus.  

PubMed

Hypoxia is an environmental stress encountered by Aspergillus fumigatus during invasive pulmonary aspergillosis (IPA). The ability of this mold to adapt to hypoxia is important for fungal virulence and genetically regulated in part by the sterol regulatory element binding protein (SREBP) SrbA. SrbA is required for fungal growth in the murine lung and to ultimately cause lethal disease in murine models of IPA. Here we identified and partially characterized four genes (dscA, dscB, dscC, and dscD, here referred to as dscA-D) with previously unknown functions in A. fumigatus that are orthologs of the Schizosaccharomyces pombe genes dsc1, dsc2, dsc3, and dsc4 (dsc1-4), which encode a Golgi E3 ligase complex critical for SREBP activation by proteolytic cleavage. A. fumigatus null dscA-D mutants displayed remarkable defects in hypoxic growth and increased susceptibility to triazole antifungal drugs. Consistent with the confirmed role of these genes in S. pombe, both ?dscA and ?dscC resulted in reduced cleavage of the SrbA precursor protein in A. fumigatus. Inoculation of corticosteroid immunosuppressed mice with ?dscA and ?dscC strains revealed that these genes are critical for A. fumigatus virulence. Reintroduction of SrbA amino acids 1 to 425, encompassing the N terminus DNA binding domain, into the ?dscA strain was able to partially restore virulence, further supporting a mechanistic link between DscA and SrbA function. Thus, we have shown for the first time the importance of a previously uncharacterized group of genes in A. fumigatus that mediate hypoxia adaptation, fungal virulence, and triazole drug susceptibility and that are likely linked to regulation of SrbA function. PMID:23104569

Willger, Sven D; Cornish, E Jean; Chung, Dawoon; Fleming, Brittany A; Lehmann, Margaret M; Puttikamonkul, Srisombat; Cramer, Robert A

2012-12-01

106

Dsc Orthologs Are Required for Hypoxia Adaptation, Triazole Drug Responses, and Fungal Virulence in Aspergillus fumigatus  

PubMed Central

Hypoxia is an environmental stress encountered by Aspergillus fumigatus during invasive pulmonary aspergillosis (IPA). The ability of this mold to adapt to hypoxia is important for fungal virulence and genetically regulated in part by the sterol regulatory element binding protein (SREBP) SrbA. SrbA is required for fungal growth in the murine lung and to ultimately cause lethal disease in murine models of IPA. Here we identified and partially characterized four genes (dscA, dscB, dscC, and dscD, here referred to as dscA-D) with previously unknown functions in A. fumigatus that are orthologs of the Schizosaccharomyces pombe genes dsc1, dsc2, dsc3, and dsc4 (dsc1-4), which encode a Golgi E3 ligase complex critical for SREBP activation by proteolytic cleavage. A. fumigatus null dscA-D mutants displayed remarkable defects in hypoxic growth and increased susceptibility to triazole antifungal drugs. Consistent with the confirmed role of these genes in S. pombe, both ?dscA and ?dscC resulted in reduced cleavage of the SrbA precursor protein in A. fumigatus. Inoculation of corticosteroid immunosuppressed mice with ?dscA and ?dscC strains revealed that these genes are critical for A. fumigatus virulence. Reintroduction of SrbA amino acids 1 to 425, encompassing the N terminus DNA binding domain, into the ?dscA strain was able to partially restore virulence, further supporting a mechanistic link between DscA and SrbA function. Thus, we have shown for the first time the importance of a previously uncharacterized group of genes in A. fumigatus that mediate hypoxia adaptation, fungal virulence, and triazole drug susceptibility and that are likely linked to regulation of SrbA function. PMID:23104569

Willger, Sven D.; Cornish, E. Jean; Chung, Dawoon; Fleming, Brittany A.; Lehmann, Margaret M.; Puttikamonkul, Srisombat

2012-01-01

107

Recent advances in photoacoustic calorimetry: Theoretical basis and improvements in experimental design  

Microsoft Academic Search

Recent developments in time-resolved photoacoustic calorimetry (PAC) are discussed. An equation is derived relating the amplitude of the maximum photoacoustic signal to parameters of a photoacoustic cell, to physical properties of the solvents, and to the energy deposited as heat. The equation is validated by a series of scaling experiments: it correctly correlates the dependence of the PAC signal on

Lui´s G. Arnaut; Richard A. Caldwell; Jeffrey E. Elbert; Lynn A. Melton

1992-01-01

108

Monitoring crystallisation of drugs from fast-dissolving oral films with isothermal calorimetry.  

PubMed

The aim of this study was to evaluate the potential of isothermal calorimetry to monitor and characterize crystallisation in drug-loaded fast-dissolving oral films. Films of polyvinylpyrrolidone (PVP) containing indomethacin were cast into glass ampoules; stability was assessed by monitoring the power changes occurring with time. Three grades of PVP (K10, K25 and K40, where the number multiplied by 1000 gives the average molecular weight) were used. Indomethacin was seen to crystallise from all PVP grades over ca. 24-48 h at two study temperatures (25 and 37 degrees C), as denoted by a large exothermic event. At 25 degrees C the exothermic event was a single peak; at 37 degrees C two peaks were observed. Subsequent analysis of the crystals with differential scanning calorimetry (DSC) and polarized light microscopy determined that the stable gamma-polymorph of indomethacin formed at 25 degrees C while both the gamma- and metastable alpha-polymorphs formed at 37 degrees C. The calorimetric data were converted to relative crystallinity as a function of time and analysed with three crystallisation models (Avrami, Tobin and Urbanovici-Segal) to determine crystallisation kinetics. Of the three models applied the Urbanovici-Segal model best described the data, although this may be because this model contains a term that effectively accounts for deviation from the Avrami model. The rate constants determined were broadly consistent irrespective of the model used. Increasing polymer molecular weight did not generally affect the crystallisation rate, although an increase in temperature did result in a concomitant increase in crystallisation rate. The data suggest that isothermal calorimetry is able to monitor drug crystallisation in polymer films and therefore the technique could be a useful tool for conducting stability assays for fast-dissolving oral medicines. PMID:19596058

Gaisford, Simon; Verma, Amit; Saunders, Mark; Royall, Paul G

2009-10-01

109

The dual-readout approach to calorimetry  

NASA Astrophysics Data System (ADS)

Simultaneous detection of the Cherenkov light and scintillation light produced in hadron showers makes it possible to measure the electromagnetic shower fraction event by event and thus eliminate the effects of fluctuations in this fraction, which limit the precision with which hadrons and jets can be detected in calorimeters. In the RD52 (DREAM) project, the possibilities of this dual-readout calorimetry are investigated and optimized. In this talk, the latest results of this project are presented. These results concern the first tests of the partially completed full-scale SuperDREAM fiber calorimeter, which were recently carried out at CERN.

Wigmans, Richard

2013-12-01

110

Characterization of supercooled liquid Ge2Sb2Te5 and its crystallization by ultrafast-heating calorimetry.  

PubMed

Differential scanning calorimetry (DSC) is widely used to study the stability of amorphous solids, characterizing the kinetics of crystallization close to the glass-transition temperature T(g). We apply ultrafast DSC to the phase-change material Ge(2)Sb(2)Te(5) (GST) and show that if the range of heating rates is extended to more than 10(4) K s(-1), the analysis can cover a wider temperature range, up to the point where the crystal growth rate approaches its maximum. The growth rates that can be characterized are some four orders of magnitude higher than in conventional DSC, reaching values relevant for the application of GST as a data-storage medium. The kinetic coefficient for crystal growth has a strongly non-Arrhenius temperature dependence, revealing that supercooled liquid GST has a high fragility. Near T(g) there is evidence for decoupling of the crystal-growth kinetics from viscous flow, matching the behaviour for a fragile liquid suggested by studies on oxide and organic systems. PMID:22426461

Orava, J; Greer, A L; Gholipour, B; Hewak, D W; Smith, C E

2012-04-01

111

Conformational study of globulin from common buckwheat (Fagopyrum esculentum Moench) by Fourier transform infrared spectroscopy and differential scanning calorimetry.  

PubMed

Fourier transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC) were used to study changes in the conformation of globulin from common buckwheat (Fagopyrum esculentum Moench) (BWG) under various environmental conditions. The IR spectrum of the native BWG showed several major bands from 1691 to 1636 cm(-1) in the amide I' region, and the secondary structure composition was estimated as 34.5% beta-sheets, 20.0% beta-turns, 16.0% alpha-helices, and 14.4% random coils. Highly acidic and alkaline pH conditions induced decreases in beta-sheet and alpha-helical contents, as well as in denaturation temperature (Td) and enthalpy of denaturation (DeltaH), as shown in the DSC thermograms. Addition of chaotropic salts (1.0 M) caused progressive decreases in ordered structures and thermal stability following the lyotropic series of anions. The presence of several protein structure perturbants also led to changes in IR band intensities and DSC thermal stabilities, suggesting protein unfolding. Intermolecular antiparallel beta-sheet (1620 and 1681 cm(-1)) band intensities started to increase when BWG was heated to 90 degrees C, suggesting the initiation of protein aggregation. Increasing the time of the preheat treatment (at 100 degrees C) caused progressive increases in Td and pronounced decreases in DeltaH, suggesting partial denaturation and reassociation of protein molecules. PMID:16190669

Choi, Siu-Mei; Ma, Ching-Yung

2005-10-01

112

Determination of the thermo-mechanical properties in starch and starch/gluten systems at low moisture content - a comparison of DSC and TMA.  

PubMed

The impact of heating rate on the glass transition (Tg) and melting transitions observed by differential scanning calorimetry (DSC) on starch and a starch/gluten blend (80:20 ratio) at low moisture content was examined. The results were compared to those determined by thermo-mechanical analysis (TMA). Comparison with dynamic mechanical thermal analysis (DMTA) and phase transition analysis (PTA) is also discussed. Higher heating rates increased the determined Tg as well as the melting peak temperatures in both starch and the starch/gluten blend. A heating rate of 5°C/min gave the most precise value of Tg while still being clearly observed above the baseline. Tg values determined from the first and second DSC scans were found to differ significantly and retrogradation of starch biopolymers may be responsible. Tg values of starch determined by TMA showed good agreement with DSC results where the Tg was below 80°C. However, moisture loss led to inaccurate Tg determination for TMA analyses at temperatures above 80°C. PMID:24751240

Homer, Stephen; Kelly, Michael; Day, Li

2014-08-01

113

7 CFR 1710.114 - TIER, DSC, OTIER and ODSC requirements.  

Code of Federal Regulations, 2010 CFR

...2010-01-01 2010-01-01 false TIER, DSC, OTIER and ODSC requirements. 1710...and Basic Policies § 1710.114 TIER, DSC, OTIER and ODSC requirements. (a...or average basis, are a TIER of 1.25, DSC of 1.25, OTIER of 1.1, and ODSC...

2010-01-01

114

Prospects for and tests of hadron calorimetry with silicon  

SciTech Connect

Hadron calorimetry with silicon may provide crucial capabilities in experiments at the high luminosity, high energy colliders of the future, particularly due to silicon's fast intrinsic speed and absolute calibration. The important underlying processes of our understanding of hadron calorimeters are reviewed to set the framework for the presentation of recent calculations of the expected performance of silicon detector based hadron calorimeters. Such devices employing uranium are expected to achieve the compensation condition (that is, the ratio of the most probable electron signal to hadron signal (e/h) is approx.1.0) based on the understanding that has been derived from the uranium-liquid argon and uranium-plastic scintillator systems. In fact, even lead-silicon calorimeters are found to achieve the attractive value for the e/h ratio of 1.16 at 10 GeV. An experimental test of these predictions is underway at CERN by the SICAPO Collaboration. 64 refs., 19 figs.

Brau, James E. [Univ. of Oregon, OR (United States). Dept. of Physics] [Univ. of Oregon, OR (United States). Dept. of Physics; Gabriel, Tony A. [Oak Ridge National Lab., TN (United States)] [Oak Ridge National Lab., TN (United States); Rancoita, P. G. [INFN, Milan (Italy)] [INFN, Milan (Italy)

1989-03-01

115

Thermal characterization of Titan's tholins by simultaneous TG-MS, DTA, DSC analysis  

NASA Astrophysics Data System (ADS)

Three samples of Titan's tholins synthesized in laboratory under simulated Titan's conditions and presenting different degrees of exposure to ambient atmosphere have been used to study in detail their thermal behavior using thermogravimetry coupled with a mass spectrometer (TG-MS), differential thermal analysis (DTA) and differential scanning calorimetry (DSC). The degradation of Titan's tholins under inert atmosphere follows a three-step consecutive decomposition: a drying stage (>150 °C) where moisture is desorbed, this stage indicated the high hydrophilicity of the tholins; a second stage, the main pyrolysis stage (150-575 °C) where endothermic decomposition begins releasing mainly ammonia, HCN, acetonitrile, and methane over a broad temperature range. Few other hydrocarbon fragments such as ethylene and propane are released but no cyclic molecules, aliphatic or aromatic, are observed. The last stage (>575 °C) is the carbonization of the material leading to a non-crystalline graphitic residue. The thermal degradation under oxygen atmosphere shows the same stages as in argon, with a shift of the thermogravimetric peaks toward lower temperatures indicating a lower thermal stability. The last stage in this case is an oxidative combustion of the char residue. This research concludes that even if Titan tholins, subjected to air contamination for few minutes to several years (varying with the storage conditions) transform to produce different C/N and C/O ratios and thermal stabilities, they undergo the same thermal degradation phases and products. This suggests that the studied three tholins have a similar main chemical structure which does not alter by the air exposure. We discuss on the possible nature of this structure.

Nna-Mvondo, Delphine; de la Fuente, José L.; Ruiz-Bermejo, Marta; Khare, Bishun; McKay, Christopher P.

2013-09-01

116

Naphthalene and Azulene I: Semimicro Bomb Calorimetry and Quantum Mechanical Calculations  

NASA Astrophysics Data System (ADS)

A novel H2O physical chemistry experiment is proposed in which the heats of combustion of naphthalene and azulene are measured using bomb calorimetry, and then the energy difference between the two molecules is computed using Gaussian 94W. Azulene is an expensive hydrocarbon ($100/gram); semimicro bomb calorimetry using the Parr 1425 makes the experiment possible using just 0.1 grams of azulene. The experimental difference obtained by students using this apparatus was -34 kcal/mole (azulene - naphthalene); the literature value is -32 kcal/mole. Using the B3LYP/6-31G(D)//RHF/6-31G(D) level of theory we compute an energy difference of -32 kcal/mole; the literature value for the gas-phase energy difference between azulene and naphthalene is -35±2 kcal/mole. Thus this experiment demonstrates that excellent agreement can be obtained between experiment and modern methods of computational chemistry.

Salter, Carl; Foresman, James B.

1998-10-01

117

Flow calorimetry and adsorption study of dibenzothiophene, quinoline and naphthalene over modified Y zeolites  

Microsoft Academic Search

The adsorptive removal of dibenzothiophene (DBT), quinoline and naphthalene in hexadecane on the zeolites, NaY, NiY and CsY, using liquid phase flow calorimetry and adsorption experiments, was studied at 30°C. NiY and CsY were prepared by the liquid phase ion-exchange method. The adsorbents were characterized by XRD, BET surface area, elemental analysis (ICP-OES) and DRIFT spectroscopic techniques. The adsorption experiments

J. Keir Thomas; Kamalakar Gunda; Peter Rehbein; Flora T. T. Ng

2010-01-01

118

Calorimetry At Very High Energy Colliders  

SciTech Connect

The capability of hadron colliders has increased to where it will soon be possible to collide protons at center of mass energies of 14 TeV with the advent of the LHC. With increasing collision energy, calorimeters become ever more essential components of a detector, and collaborations often choose very different technologies to meet their goals. From the perspective of a high energy particle and nuclear physicist, a survey is presented of the differences in design considerations and actual performance of the wide variety of calorimeters used in modern hadron colliders such as the Tevatron, RHIC, and LHC. The lessons learned and some ideas for future development of calorimetry will also be discussed.

Chiu, Mickey [Brookhaven National Laboratory, Upton NY 11973 (United States)

2011-06-01

119

Profiles in Leadership: Clifton J. Latiolais, MSc, DSc  

PubMed Central

The Director’s Forum series is designed to guide pharmacy leaders in establishing patient-centered services in hospitals and health systems. August 2013 marks the 50th anniversary of the publication of the Mirror to Hospital Pharmacy, which was a comprehensive study of pharmacy services in the United States. The late Clifton J. Latiolais, MS, DSc, served as the assistant program director for the study and was a co-author of the Mirror. The late Don E. Francke, MS, DSc, was the lead author of the Mirror and the principal investigator of the federally funded study that reviewed hospital pharmacy services across the United States. The next 2 articles in Director’s Forum profile the leadership of Drs. Latiolais and Francke. This article highlights Dr. Latiolais (“Clif”) by briefly reviewing his biography and key career accomplishments, describing his leadership philosophy, and translating that philosophy to today’s health care challenges. Clif’s influence on health system pharmacy serves as an example of effective leadership. This historical perspective on Clif’s leadership, as seen through the eyes of those who knew him, provides directors of pharmacy a valuable leadership viewpoint as they develop strategies to enhance patient-centered pharmacy services. PMID:24421540

White, Sara; Godwin, Harold N.; Weber, Robert J.

2013-01-01

120

A study of the aging of silicone breast implants using 29Si, 1H relaxation and DSC measurements.  

PubMed

In this study 26 previously implanted silicone breast implants from the same manufacturer (Dow Corning) were investigated with two different analytical methods to characterize potential aging processes such as migration of monomer material from the gel and shell to local and distant sites, chemical alterations of the polymer, and infiltration of body compounds such as lipids. (1)H and (29)Si NMR relaxation measurements (spin-lattice, T1, and spin-spin, T2, relaxation times) were used to study the molecular dynamics of polysiloxane chains, both in gels and in shells. In addition, changes in physical properties were monitored by differential scanning calorimetry (DSC). The results of these measurements indicate that NMR relaxation times are influenced by implant generation, implantation time, shell texture and implant status. (1)H T2 values of shells and gels show a tendency to increase with increasing implantation time, indicating higher mobility and possible disintegration of the polymer network of older implants. Furthermore, the data suggest that aging also involves the migration of low cyclic molecular weight (LMW) silicone and linear chain polymer material from the gels into the shells. The high "bleeding" rate of second-generation (G2) implants (implantation period around 1973-1985), exhibiting thin shells is reflected in reduced relaxation times of these devices, most likely due to a loss of low molecular weight fractions from the gels. Moreover, "gel bleeding" also influences the melting behavior observed in DSC studies. Increased shell rigidity (high Tm and Tg) tends to be correlated with longer (29)Si relaxation times of the corresponding gels, suggesting a reduced transfer of LMW silicones and linear chain polymer from the gel to the shell and to the outside. Remarkably, textured implants seem to be less susceptible to degradation processes than implants with thin shells. PMID:15046931

Birkefeld, Anja Britta; Eckert, Hellmut; Pfleiderer, Bettina

2004-08-01

121

TG-DSC-FTIR Analysis of Cyanobacteria Pyrolysis  

NASA Astrophysics Data System (ADS)

Pyrolysis of cyanobacteria from Dianchi lake was investigated by TG-DSC-FTIR analysis at different heating rates (10, 20, 40°C/min). The results indicated that the pyrolysis of cyanobacteria can be divided into four stages: evaporation, depolymerization, devolatilization and carbonization. Meanwhile, the initial weight-loss temperature, weight-loss extreme position, endothermic and exothermic peaks were moved to higher temperature with the increaseing of the heating rate. The kinetic analysis was made with Popescu method. It indicated that the best kinetic model for the pyrolysis of cyanobacteria was the cylindrical symmetry of the phase boundary reaction model. The main pyrolysis gases checked with real-time online FTIR were HCN, NH3, CO, CO2, water vapor and hydrocarbons.

Supeng, Luo; Guirong, Bao; Hua, Wang; Fashe, Li; Yizhe, Li

122

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

NASA Astrophysics Data System (ADS)

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 (200-350 C - nominally ‘labile’/low MW, 350-500 C - increasing recalcitrance/MW and 500-650 C - recalcitrant/high MW). Samples from all three systems show similar stability distributions with broader less resolved peaks for DOC and soil with intense more resolved peaks for mature compost. DOC flocculated with Iron (Fe) or aluminum (Al) broadened and shifted peak stability to higher temps doubling energy yield compared to DOC (least complex most change). Fe and Al oxides added during composting broadened peaks with shifts towards higher temps with more modest increases in energetic yield(increased complexity reduced change). Soils illustrate a broad and balanced distribution that is fairly robust to treatment or input (most complex least change). Generally metal oxides increased thermal stability and system complexity altering stability distributions towards the diverse and complex soil system. Is the complex and attenuating nature of soil the benchmark to quantify less stable and complex systems based on their components, alterations and metrics of thermal stability and order? Our research is an initial test of this idea supported by reproducible thermal metrics to assess the attenuation of C through natural systems.

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

2010-12-01

123

Calorimetry using organic scintillators, 'a sideways perspective'.  

SciTech Connect

Over the last two decades, calorimetry baaed on organic scintillators has developed into an excellent technology for many experimental situations in high energy physics. The primary difficulty, that of extracting the light signals, has benefited from two milestone innovations. The first was the use of wavelength-shifting bars to allow light to be efficiently collected from large areas of scintillator and then readily piped to a readout device. The second of these was the extension of this approach to plastic wavelength-shifting optical fibers whose great flexibility and small diameter allowed a minimum of detector volume to be compromised by the read-out. These two innovations coupled with inventiveness have produced many varied and successful calorimeters. Equal response to both hadronic and electromagnetic showers can be realized in scintillator-based calorimeters. However, in general this is not the case and it is likely that in the search for greater performance, in the future, combined tracking and calorimeter systems will be required.

Proudfoot, J.

1999-09-10

124

Hadron sampling calorimetry, a puzzle of physics  

NASA Astrophysics Data System (ADS)

The physics involved in hadron sampling calorimetry covers the wide energy range between high energy, medium energy, nuclear and atomic physics. All the processes contributing to energy depositions are discussed as well as illustrated by model calculations. The sampling fraction which determines the fraction of incident energy, which becomes visible in the detector layers, turns out to be strongly affected by the type of energy flow and the atomic number Z of the materials used. Normalized to mips, such fractions might range in the examples discussed between 0 and 2. Model calculations have been based on the HERMES scheme, which makes use of improved versions of the HET, the MORSE and the new developed DYMO code. The results allow to evaluate the degree of compensation and to predict e/h ratios. Such predictions agree quite well with the experimental results. In case of depleted uranium/scintillator sampling structures, compensation can be tuned by means of layer thicknesses. Finally, first results are presented for the investigation of fluctuations and correlations from model calculations evaluated event-by-event.

Brückmann, Hanno; Anders, Bernd; Behrens, Ulf

1988-01-01

125

Differential scanning calorimetry of plant cell walls  

SciTech Connect

High-sensitivity differential scanning calorimetry has been used to study the phase transition of cell wall preparations of the elongating and mature regions of soybean hypocotyls and of celery epidermis and collenchyma strands. A step-like transition believed to be glass transition was observed in walls isolated from the elongating region of soybean hypocotyls at 52.9C. Addition of 1 mM CaCl{sub 2} to the cell wall preparation increased the transition temperature to 60.8C and greatly reduced the transition magnitude. In walls from the mature region, the transition was small and occurred at a higher temperature (60.1C). Addition of calcium to the mature region cell wall had little effect on the transition. Based on the known interactions between calcium and pectin, the authors propose that calcium affects the glass transition by binding to the polygalacturonate backbone of wall pectin, resulting in a more rigid wall with a smaller transition at a higher temperature. The mature region either has more calcium in the wall or has more methyl-esterified pectin, making it less responsive to added calcium.

Lin, Liangshiou; Varner, J.E. (Washington Univ., St. Louis, MO (United States)); Yuen, H.K. (Monsanto Co., St. Louis, MO (United States))

1991-03-15

126

The heat capacity of two natural chlorite group minerals derived from differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

The heat capacity of natural chamosite (XFe=0.889) and clinochlore (XFe=0.116) were measured by differential scanning calorimetry (DSC). The samples were characterised by X-ray diffraction, microprobe analysis and Mössbauer spectroscopy. DSC measurements between 143 and 623K were made following the procedure of Bosenick etal. (1996). The fitted data for natural chamosite (CA) in Jmol-1K-1 give: Cp,CA = 1224.3-10.685×103×T -0.5-6.4389× 106×T -2+8.0279×108×T -3 and for the natural clinochlore (CE): Cp,CE = 1200.5-10.908×103×T -0.5- 5.6941×106×T -2+7.1166×108×T -3. The corrected Cp-polynomial for pure end-member chamosite (Fe5Al)[Si3AlO10](OH)8 is Cp,CAcor = 1248.3-11.116× 103×T -0.5-5.1623×106×T -2+7.1867×108×T -3 and the corrected Cp-polynomial for pure end-member clinochlore (Mg5Al)[Si3AlO10](OH)8 is Cp,CEcor = 1191.3-10.665×103×T -0.5-6.5136×106×T -2+ 7.7206×108×T -3. The corrected Cp-polynomial for clinochlore is in excellent agreement with that in the internally consistent data sets of Berman (1988) and Holland and Powell (1998). The derived Cp-polynomial for chamosite (Cp,CAcor) leads to a 4.4% higher heat capacity, at 300K, compared to that estimated by Holland and Powell (1998) based on a summation method. The corrected Cp-polynomial (Cp,CAcor) is, however, in excellent agreement with the computed Cp-polynomial given by Saccocia and Seyfried (1993), thus supporting the reliability of Berman and Brown's (1985) estimation method of heat capacities.

Bertoldi, C.; Benisek, A.; Cemic, L.; Dachs, E.

127

Study of the Crystalline Morphology Evolution of PET and PET/PC Blends by Time-resolved Synchrotron Small Angle X-ray Scattering (SAXS) and DSC  

SciTech Connect

Isothermal melt crystallization of poly(ethylene terephthalate)(PET) and PET/PC (polycarbonate) blend, with and without a transesterification catalyst, was studied by time-resolved small-angle X-ray scattering (SAXS) and differential scanning calorimetry (DSC) in order to achieve the variation of the morphological parameters throughout the whole crystallization time. For neat PET, the catalyst promotes a decrease of the crystal lamellar thickness but for the blend no variations were observed. The effect of incorporation of catalyst in crystallization kinetics was very distinct in PET pure and the blend: in the former the catalyst leads to an increase of this kinetics while for the latter it was observed a decreasing.

Barbosa, Irineu; Larocca, Nelson M.; Hage, Elias [Dep. de Engenharia de Materiais, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil); Plivelic, Tomas S.; Torriani, Iris L. [Laboratorio Nacional de Luz Sincrotron, Campinas, SP (Brazil); Mantovani, Gerson L. [Centro de Engenharia, Modelagem e Ciencias Sociais Aplicadas, Universidade Federal do ABC, 09090-400 Santo Andre, SP (Brazil)

2009-01-29

128

Physicochemical characterization of silicon-containing glycolipids by DSC, FT-Raman spectroscopy and X-ray diffraction.  

PubMed

Derivatives of dimethylalkylchlorosilanes are novel substances which may be used in formulations for drug targeting. In order to design their properties it is essential to perform physicochemical characterization. For this purpose, a combination of differential scanning calorimetry (DSC), FT-Raman spectroscopy and X-ray diffraction is well suited. For the starting material dimethyloctadecylchlorosilane (DMOC), the assignment of Raman bands is discussed. The influence of sugar-containing head groups on the structures of the hydrocarbon chains of 1-O-(dimethyldodecylsilyl)-[2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside] and 1-O-(dimethyloctadecylsilyl)-[2,3,4,6-tetra-O-acetyl-beta-D-glucopyranoside] was investigated using the band position of the symmetric methylene mode. The temperature dependence of conformationally sensitive bands in the CH(2)-stretching region (2800-2900 cm(-1)), C-C-stretching region (1000-1150 cm(-1)) and CH(3)-rocking region (830-900 cm(-1)) was studied to characterize the state of order of the alkyl chains. Using X-ray diffraction, the repeating distances of layered structures was determined. The phase transitions occurring were found to be completely reversible. The subcell of DMOC shows an orthorhombic perpendicular packing structure in the crystalline state. PMID:12787939

Uhr, M; Wartewig, S; Unruh, T; Richter, H

2003-06-01

129

Interaction of a new anticancer prodrug, gemcitabine-squalene, with a model membrane: coupled DSC and XRD study.  

PubMed

Gemcitabine is an anticancer nucleoside analogue active against a wide variety of solid tumors. However it is rapidly deaminated to an inactive metabolite, leading to short biological half-life and induction of resistance. A new prodrug of gemcitabine, coupling squalene to gemcitabine (GemSq), has been designed to overcome the above drawbacks. It has been previously shown that this prodrug displays significantly higher anticancer activity than gemcitabine against leukemia. In the present study the structural modifications of dipalmitoylphosphatidylcholine (DPPC) model membranes induced by increasing concentrations of GemSQ have been investigated using small and wide angle X-ray scattering (SWAXS) and differential scanning calorimetry (DSC). At room temperature an unusual inverse bicontinuous cubic phase formed over a broad composition range. The basic bilayer structure displayed an intermediate order between those of the gel and fluid phases of DPPC. A reversible transition to a fluid lamellar phase occurred upon heating. The transitions between these two phases were governed by different mechanisms depending on the GemSq concentration in the membrane. Finally, the biological relevance of these observations for the cytotoxic activity of GemSq has been discussed. PMID:20435013

Pili, Barbara; Bourgaux, Claudie; Amenitsch, Heinz; Keller, Gérard; Lepêtre-Mouelhi, Sinda; Desmaële, Didier; Couvreur, Patrick; Ollivon, Michel

2010-08-01

130

Physicochemical aging mechanisms in soil organic matter assessed by NMR and DSC  

NASA Astrophysics Data System (ADS)

Soil organic matter (SOM) controls a variety of processes occurring at biogeochemical interfaces acting as a highly dynamic matrix. Results from previous studies showed that SOM undergoes physicochemical matrix aging. It was hypothesized that the formation and disruption of water molecule bridges are responsible for this aging process. The objective of this study was to evaluate this hypothesis using three peat samples from different sample sites in Germany: a peat from Rhinluch, 60 km northwest of Berlin, a black peat and a white peat from Fuhrberg near Hannover. The composition determined by pyrolysis field ionisation mass spectrometry was similar for the Rhinluch peat and the Fuhrberg black peat, but showed a distinctly higher carbohydrate content for the Fuhrberg white peat. To elucidate mechanisms of physicochemical matrix aging and to evaluate the hypothesis of water molecule bridges we carried out heating-cooling events in hermetically sealed containers and measured the response by NMR and DSC as a function of time. The heating-cooling event started with heating for 10 minutes at 110 °C followed by rapid cooling and isothermal storage at 19 °C for at least four months. All peats show a non-reversing step transition between 40 °C and 65 °C similar to transitions observed in previous studies. The black peat from Fuhrberg showed an additional step transition between 35 °C and 45 °C. The temperature of the non-reversing step transition immediately decreased by 25 °C in response to the heating-cooling event and slowly re-increased upon isothermal storage within several months. The temperature of the reversing transition showed a similar behaviour but not as strongly as the non-reversing transition. The proton NMR in combination with line separation into Lorentz and Gauss lines was used to differentiate between the different kinds of water. In dependence of the water bridge status the portions of these lines on the total wide line spectrum change; at a higher amount of movable water the portion of the Lorentz line, as an indicator for the movable water molecules, should increase. The separation of the proton NMR wide line spectra for the Rhinluch peat into the different lines showed the expected behaviour but for the Fuhrberg black peat the opposite effect was observed. The results of the differential scanning calorimetry support the hypothesis that water molecules bridge molecular segments of soil organic matter. The proton NMR-measurements for the Rhinluch peat also supports this hypothesis, while the NMR-results for the Fuhrberg peat are contradicting it. This contribution discusses potential explanations for these (partly unexpected) results.

Schwarz, J.; Jaeger, A.; Bertmer, M.; Schlichting, A.; Leinweber, P.; Schaumann, G. E.

2009-04-01

131

PREFACE: XIV International Conference on Calorimetry in High Energy Physics  

NASA Astrophysics Data System (ADS)

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 (Texas Tech University), Weidong Li (IHEP) 3) Readout techniques - Gerald Eigen (University of Bergen), Zheng Wang (IHEP) 4) Operating calorimeters and calibration - Marat Gataullin (CERN), Francesco Lanni (BNL) 5) Future calorimetry - Tohru Takeshita (Shinshu University), Lei Xia (Argonne National Laboratory) 6) Astrophysics and neutrino calorimetry - Giuliana Fiorillo (INFN), Hiro Tajima (SLAC) List of Participants AKCHURIN, NuralTexas Tech University AN, ZhenghuaIHEP AUFFRAY, EtiennetteCERN BANFI, DaniloUniversità degli Studi di Milano, INFN BASHARINA-FRESHVILLE, AnastasiaUniversity College London BEAUCHEMIN, Pierre-HuguesUniversity of Oxford BENAGLIA, Andrea DavideUniversity of Milano - Bicocca and INFN BIAN, JianminIHEP BIINO, CristinaINFN BILKI, BurakUniversity of Iowa BLAHA, JanLAPP BOUDRY, VincentLLR / CNRS-IN2P3 CAI, XiaoIHEP CAPONE, AntonioPhysics Department University "La Sapienza" and INFN CAVALLARI, FrancescaCERN and INFN Rome CECCHI, ClaudiaUniversity di Perugia e INFN CHANG, JinfanIHEP CHEN, HuchengBrookhaven National Laboratory CHILDERS, TaylorUniversität Heidelberg - Kirchhoff-Institut für Physik DAO, ValerioGeneva University - DPNC DE LA TAILLE, ChristopheIN2P3/OMEGA-LAL DIEMOZ, MarcellaINFN Roma DOTTI, AndreaCERN EIGEN, GeraldUniversity of Bergen EPIFANOV, DenisBudker Institute of Nuclear Physics FAIVRE, JulienLPSC Grenoble France FANG, JianIHEP FANG, ShuangshiIHEP FANTONI, AlessandraINFN - LNF FERRI, FedericoCEA/Saclay Irfu/SPP FERRONI, FernandoSapienza University & INFN Roma FISK, Henry EugeneFermilab GABALDON, CarolinaCERN GARUTTI, ErikaDESY GAUDIO, GabriellaIstituto Nazionale di Fisica Nucleare - Sezione di Pavia GILLBERG, DagCarleton University GIOVANNINI, PaolaMax-Planck-Institut für Physik GLAZOV, AlexanderDESY GRACHOV, OlegUniversity of Kansas HAPPACHER, FabioINFN HE, MiaoIHEP HORI, YasutoUniversity of Tokyo, CNS HU, TaoIHEP HULTH, Per-OlofStockholm University JUN, Soon YungCarnegie Mellon University JURK, StefanISEG Spezialelektronik gmbH KAVATSYUK, MyroslavKVI, University of Groningen KHRAMOV, EvgenyJoint Institute

Wang, Yifang

2011-03-01

132

Profiles in Leadership: Donald E. Francke, MSc, DSc (Hon).  

PubMed

The Director's Forum series is designed to guide pharmacy leaders in establishing patient-centered services in hospitals and health systems. August 2013 marked the 50th anniversary of the publication of the Mirror to Hospital Pharmacy, the results of a federally funded comprehensive study of pharmacy services in the United States. The late Don E. Francke, MS, DSc, was the lead author of the Mirror and the principal investigator for the US Public Health Service grant W-45. To celebrate the anniversary of the Mirror, the Director's Forum is profiling the leadership styles of Drs. Latiolais and Francke. September's article highlighted Dr. Clifton J. Latiolais; this month's Director's Forum reviews Dr. Francke's biography and key career accomplishments, describes his leadership philosophy, and translates that philosophy to today's health care challenges. Don's influence on health system pharmacy serves as an example of effective leadership. This historical perspective provides directors of pharmacy a valuable leadership view as they develop strategies to enhance patient-centered pharmacy services. PMID:24421553

Stevenson, James G; Beham, Rachel E; Weber, Robert J

2013-10-01

133

Profiles in Leadership: Donald E. Francke, MSc, DSc (Hon)  

PubMed Central

The Director’s Forum series is designed to guide pharmacy leaders in establishing patient-centered services in hospitals and health systems. August 2013 marked the 50th anniversary of the publication of the Mirror to Hospital Pharmacy, the results of a federally funded comprehensive study of pharmacy services in the United States. The late Don E. Francke, MS, DSc, was the lead author of the Mirror and the principal investigator for the US Public Health Service grant W-45. To celebrate the anniversary of the Mirror, the Director’s Forum is profiling the leadership styles of Drs. Latiolais and Francke. September’s article highlighted Dr. Clifton J. Latiolais; this month’s Director’s Forum reviews Dr. Francke’s biography and key career accomplishments, describes his leadership philosophy, and translates that philosophy to today’s health care challenges. Don’s influence on health system pharmacy serves as an example of effective leadership. This historical perspective provides directors of pharmacy a valuable leadership view as they develop strategies to enhance patient-centered pharmacy services. PMID:24421553

Stevenson, James G.; Beham, Rachel E.; Weber, Robert J.

2013-01-01

134

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

PubMed Central

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 (Tm) of liposomes. However, reduction in the enthalpy of the transition (?H°) following coating with CHM supports an anchoring mechanism to the bilayer by the polymer, whereas no change or little increase in the ?H° 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. PMID:23181079

Tabbakhian, M.; Rogers, J.A.

2012-01-01

135

Thermal and Structural Behavior of Dioctadecyldimethylammonium Bromide Dispersions Studied by Differential Scanning Calorimetry and X-Ray Scattering  

PubMed Central

Dioctadecyldimethylammonium bromide (DODAB) is a double chain cationic lipid, which assembles as bilayer structures in aqueous solution. The precise structures formed depend on, e.g., lipid concentration and temperature. We here combine differential scanning calorimetry (DSC) and X-ray scattering (SAXS and WAXS) to investigate the thermal and structural behavior of up to 120 mM DODAB in water within the temperature range 1–70°C. Below 1 mM, this system is dominated by unilamellar vesicles (ULVs). Between 1 and 65 mM, ULVs and multilamellar structures (MLSs) co-exist, while above 65 mM, the MLSs are the preferred structure. Depending on temperature, DSC and X-ray data show that the vesicles can be either in the subgel (SG), gel, or liquid crystalline (LC) state, while the MLSs (with lattice distance d ?=?36.7 Å) consist of interdigitated lamellae in the SG state, and ULVs in the LC state (no Bragg peak). Critical temperatures related to the thermal transitions of these bilayer structures obtained in the heating and cooling modes are reported, together with the corresponding transition enthalpies. PMID:22970291

Feitosa, Eloi; Adati, Renata D.; Hansson, Per; Malmsten, Martin

2012-01-01

136

An Experimental Study of Transient Liquid Phase Bonding of the Ternary Ag-Au-Cu System Using Differential Scanning Calorimetry  

NASA Astrophysics Data System (ADS)

An experimental approach using differential scanning calorimetry (DSC) has been applied to quantify the solid/liquid interface kinetics during the isothermal solidification stage of transient liquid phase (TLP) bonding in an Ag-Au-Cu ternary alloy solid/liquid diffusion couple. Eutectic Ag-Au-Cu foil interlayers were coupled with pure Ag base metal to study the effects of two solutes on interface motion. Experimental effects involving baseline shift and primary solidification contribute to a systematic underestimation of the fraction of liquid remaining. A temperature program has been used to quantify and correct these effects. The experimental results show a linear relationship between the interface position and the square root of the isothermal hold time. The shifting tie line composition at the interface has been shown to affect the DSC results; however, the impact on the calculated interface kinetics has been shown to be minimal in this case. This work has increased the knowledge of isothermal solidification in ternary alloy systems and developed accurate experimental methods to characterize these processes, which is valuable for designing TLP bonding schedules.

Kuntz, M. L.; Panton, B.; Wasiur-Rahman, S.; Zhou, Y.; Corbin, S. F.

2013-08-01

137

New approach to study starch gelatinization applying a combination of hot-stage light microscopy and differential scanning calorimetry.  

PubMed

To overcome the difficulty of the original polarizing microscope-based method in monitoring the gelatinization of starch, a new method for dynamically monitoring the gelatinization process, integral optical density (IOD), which was based on the digital image analysis technique, was proposed. Hot-stage light microscopy and differential scanning calorimetry (DSC) techniques were coupled to study the dynamic changes of three types of starches: type A (corn starch), type B (potato starch), and type C (pea starch), during the gelatinization process in an excess water system. A model of response difference change of crystallite could represent the responding intensity of crystallization changes in the process of starch gelatinization. Results demonstrated that three crystalline types of starch underwent a process of swelling, accompanied with gradual disappearing of the crystallite. This difference was mainly associated with the diversity and composition of the starch structure. The IOD method was of advantage compared to the previous traditional methods that are based on a polarization microscope, such as counting the particle number and calculating polarization area methods, because it was the product of two parameters: optical density and area, which would be a response of both light intensity and area of birefringence light. The single peak in DSC corresponded to the combination of crystalline helix-helix dissociation and the reduction of the molecule helix-coil transition, while the gelatinization degree measured by the IOD method mainly corresponded to the helix-helix dissociation. The gelatinization mechanism could be revealed clearer in this study. PMID:23339369

Li, Qian; Xie, Qin; Yu, Shujuan; Gao, Qunyu

2013-02-13

138

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 3: TCP/IP -Endereamento * Pg. 1  

E-print Network

REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 3: TCP/IP - Endereçamento * Pág. 1: Identificar unicamente uma rede na Internet; Identificar unicamente cada máquina de uma rede. ! Um endereço . 165 . 166 . 0 200 . 201 . 203 . 255 REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 3

Cirne, Walfredo

139

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

SciTech Connect

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 %C2%B0C very little oxidation took place; at 850 %C2%B0C oxidation occurred after an induction period, while at 950 %C2%B0C oxidation occurred without an induction period. At oxidation temperatures between 1050 and 1150 %C2%B0C rapid passivation of the surface of the aluminum foil occurred, while at 1250 %C2%B0C 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.

Coker, Eric Nicholas

2013-10-01

140

Standard enthalpies of formation of some 3d transition metal carbides by high temperature reaction calorimetry  

Microsoft Academic Search

The standard enthalpies of formation of some 3d transition metal carbides have been measured by high-temperature reaction calorimetry. The following results are reported: (All data in kJ\\/mole of atoms). V4C3:?(40.3±1.2); Cr7C3:?(14.1±0.8); Mn5C2:?(8.9±1.5); Mn7C3:?(9.1±1.3); Fe3C:4.7±1.1; Co2C:2.8±1.3; Co3C: 2.4±1.4; Ni3C:1.2±1.3. These values were all obtained by direct synthesis experiments. For TiC we found?(92.9±8.9) by solute-solvent drop calorimetry. The results are compared with

S. V. Meschel; O. J. Kleppa

1997-01-01

141

Perfusion calorimetry in the characterization of solvates forming isomorphic desolvates.  

PubMed

In this study, the potential of perfusion calorimetry in the characterization of solvates forming isomorphic desolvates was investigated. Perfusion calorimetry was used to expose different hydrates forming isomorphic desolvates (emodepside hydrates II-IV, erythromycin A dihydrate and spirapril hydrochloride monohydrate) to stepwise increasing relative vapour pressures (RVP) of water and methanol, respectively, while measuring thermal activity. Furthermore, the suitability of perfusion calorimetry to distinguish the transformation of a desolvate into an isomorphic solvate from the adsorption of solvent molecules to crystal surfaces as well as from solvate formation that is accompanied by structural rearrangement was investigated. Changes in the samples were confirmed using FT-Raman and FT-IR spectroscopy. Perfusion calorimetry indicates the transformation of a desolvate into an isomorphic solvate by a substantial exothermic, peak-shaped heat flow curve at low RVP which reflects the rapid incorporation of solvent molecules by the desolvate to fill the structural voids in the lattice. In contrast, adsorption of solvent molecules to crystal surfaces is associated with distinctly smaller heat changes whereas solvate formation accompanied by structural changes is characterized by an elongated heat flow. Hence, perfusion calorimetry is a valuable tool in the characterization of solvates forming isomorphic desolvates which represents a new field of application for the method. PMID:21726637

Baronsky, Julia; Preu, Martina; Traeubel, Michael; Urbanetz, Nora Anne

2011-09-18

142

Hydration and Lyotropic Melting of Amphiphilic Molecules: A Thermodynamic Study Using Humidity Titration Calorimetry.  

PubMed

The hydration of the lipid 1-palmitoyl-2-oleoylphosphatidylcholine (POPC) and of the cationic detergent dodecyltrimethylammonium bromide (DTAB) has been studied by means of isothermal titration calorimetry (ITC), gravimetry, and infrared (IR) spectroscopy. During the experiments films of the amphiphiles are perfused by an inert gas of variable relative humidity. The measurement of adsorption heats using ITC represents a new adaptation of adsorption calorimetry which has been called the humidity titration technique. This method yields the partial molar enthalpy of water upon adsorption. It is found to be endothermic with respect to the molar enthalpy of water on condensation for the water molecules which interact directly with the headgroups of POPC and DTAB. Consequently, the spontaneous hydration of the amphiphiles is entropy driven in an aqueous environment. IR spectroscopy shows that hydration is accompanied by the increase in the conformational and/or motional freedom of the amphiphilic molecules upon water binding. In particular, a lyotropic chain melting transition is induced at a certain characteristic relative humidity. This event is paralleled by the adsorption of water. The corresponding exothermic adsorption heat is consumed completely (POPC) or partially (DTAB) by the hydrocarbon chains upon melting. Differential scanning calorimetry was used as an independent method to determine transition enthalpies of the amphiphiles at a definite hydration degree. Water binding onto the headgroups is discussed in terms of hydrogen bonding and polar interactions. The adsorption isotherms yield a number of approximately 2.6 tightly bound water molecules per POPC and DTAB molecule. Copyright 1999 Academic Press. PMID:10607439

Binder; Kohlstrunk; Heerklotz

1999-12-15

143

Microphase separation in copolymers of hydrophilic PEG blocks and hydrophobic tyrosine-derived segments using simultaneous SAXS/WAXS/DSC  

SciTech Connect

Hydration- and temperature-induced microphase separations were investigated by simultaneous small- and wide-angle X-ray scattering (SAXS and WAXS) and differential scanning calorimetry (DSC) in a family of copolymers in which hydrophilic poly(ethylene glycol) (PEG) blocks are inserted randomly into a hydrophobic polymer made of either desaminotyrosyl-tyrosine ethyl ester (DTE) or iodinated I{sub 2}DTE segments. Iodination of the tyrosine rings in I{sub 2}DTE increased the X-ray contrast between the hydrophobic and hydrophilic segments in addition to facilitating the study of the effect of iodination on microphase separation. The formation of phase-separated, hydrated PEG domains is of considerable significance as it profoundly affects the polymer properties. The copolymers of DTE (or I{sub 2}DTE) and PEG are a useful model system, and the findings presented here may be applicable to other PEG-containing random copolymers. In copolymers of PEG and DTE and I{sub 2}DTE, the presence of PEG depressed the glass transition temperature (T{sub g}) of the copolymer relative to the homopolymer, poly(DTE carbonate), and the DTE/I{sub 2}DTE segments hindered the crystallization of the PEG segments. In the dry state, at large PEG fractions (>70 vol%), the PEG domains self-assembled into an ordered structure with 14-18 nm distance between the domains. These domains gave rise to a SAXS peak at all temperatures in the iodinated polymers, but only above the T{sub g} in non-iodinated polymers, due to the unexpected contrast-match between the crystalline PEG domains and the glassy DTE segments. Irrespective of whether PEG was crystalline or not, immersion of these copolymers in water resulted in the formation of hydrated PEG domains that were 10-20 nm apart. Since both water and the polymer chains must be mobile for the phase separation to occur, the PEG domains disappeared when the water froze, and reappeared as the ice began to melt. This transformation was reversible, and showed hysteresis as did the melting of ice and freezing of the water incorporated into the polymer. PEG-water complexes and PEG-water eutectics were observed in WAXS and DSC scans, respectively.

Murthy, N.S.; Wang, W.; Kohn, J. (Rutgers); (Vermont)

2010-10-22

144

Combined microwave\\/conventional-heating calorimetry  

Microsoft Academic Search

A calorimetric device intended to study the 'microwave effect' - an apparent acceleratio n in kinetics or lowering of transition temperatures in inorganic and organic systems under the influence of microwave radiation - is being developed. Previous studies have often compared experiments where the thermal energy has been supplied using conventional heating and microwave power in different equipment. This leads

J G P Binner; B Vaidhyanathan

145

DSC Evidence for Microstructure and Phase Transitions in Polyethylene Melts at High Temperatures  

E-print Network

polyethylenes of types HDPE, LDPE, and LLDPE. DSC data were obtained for a range of heating and cooling rates. Also, commercial samples of low-density polyethylene (LDPE) and two linear-low-density polyethylenes

Hussein, Ibnelwaleed A.

146

Kinetics of the Thermal Degradation of Erica Arborea by DSC: Hybrid Kinetic Method D. Cancellieri*  

E-print Network

inflammable species in Mediterrannean area. DSC curves showing two overlapped exothermic peaks (Exotherm 1. In a second time, a Model Free Method was applied on each isolated curve to determine the apparent activation

Paris-Sud XI, Université de

147

Direct self-control (DSC) of inverter-fed induction machine  

Microsoft Academic Search

The new direct self-control (DSC) is a simple method of signal processing that gives converter-fed three-phase machines an excellent dynamic performance. To control the torque of, say, an induction motor, it is sufficient to process the measured signals of the stator currents and the total flux linkages only. In the basic version of DSC, the power semiconductors of a three-phase

M. Depenbrock

1988-01-01

148

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

PubMed

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. PMID:25325962

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

2015-01-01

149

High resolution optical calorimetry for synchrotron microbeam radiation therapy  

Microsoft Academic Search

We propose the application of optical calorimetry to measure the peak to valley ratio for synchrotron microbeam radiation therapy (MRT). We use a modified Schlieren approach known as reference image topography (RIT) which enables one to obtain a map of the rate of change of the refractive index in a water bath from which the absorbed dose can be determined

T. Ackerly; J. C. Crosbie; A. Fouras; G. J. Sheard; S. Higgins; R. A. Lewis

2011-01-01

150

Calorimetry in ZEUS: Lessons for the future  

SciTech Connect

The storage ring facility HERA, under construction at the DESY Laboratory, will collide 30 GeV e/sup /minus// with 820 GeV protons when the machine is first turned on in 1990. Four interaction regions being provided. Subsequently either e/sup /minus// or e beams can be used and a facility for producing longitudinal polarization of the electrons at the interaction points will be provided. Both the center-of-mass energy ( s = 314 GeV) and the momentum transfer (Q/sub max/S /approximately/ 10V GeVS) are substantially higher than in any deep inelastic scattering studies to date. The HERA program will be the natural extension of both the neutrino and the muon scattering experiments done at CERN and Fermilab. With the design luminosity of 1.5 10T cm/sup /minus/2/ sec/sup /minus/1/ experiments with 200 pb/sup /minus/1/ of integrated luminosity will be possible. HERA will be the first electron-quark collider. The energy is substantially higher than LEP, and the events will be cleaner than those resulting from p/bar p/ collisions. It provides the third leg that will support the physics stool of the 1990s. In neutral current events, the z exchange graph is comparable in strength to the photon exchange and the charged current events will provide unique insights into the W coupling. There will be substantial rates of heavy quark production. Two detectors are under construction: H1 uses a large solenoid with a liquid argon calorimeter inside the coil, ZEUS uses a smaller magnet with uranium-scintillator calorimeters outside of the coil. 4 refs., 11 figs.

Derrick, M.

1988-01-01

151

What does calorimetry and thermodynamics of living cells tell us?  

PubMed

This article presents and compares several thermodynamic methods for the quantitative interpretation of data from calorimetric measurements. Heat generation and absorption are universal features of microbial growth and product formation as well as of cell cultures from animals, plants and insects. The heat production rate reflects metabolic changes in real time and is measurable on-line. The detection limit of commercially available calorimetric instruments can be low enough to measure the heat of 100,000 aerobically growing bacteria or of 100 myocardial cells. Heat can be monitored in reaction vessels ranging from a few nanoliters up to many cubic meters. Most important the heat flux measurement does not interfere with the biological process under investigation. The practical advantages of calorimetry include the waiver of labeling and reactants. It is further possible to assemble the thermal transducer in a protected way that reduces aging and thereby signal drifts. Calorimetry works with optically opaque solutions. All of these advantages make calorimetry an interesting method for many applications in medicine, environmental sciences, ecology, biochemistry and biotechnology, just to mention a few. However, in many cases the heat signal is merely used to monitor biological processes but only rarely to quantitatively interpret the data. Therefore, a significant proportion of the information potential of calorimetry remains unutilized. To fill this information gap and to motivate the reader using the full information potential of calorimetry, various methods for quantitative data interpretations are presented, evaluated and compared with each other. Possible errors of interpretation and limitations of quantitative data analysis are also discussed. PMID:25461814

Maskow, Thomas; Paufler, Sven

2014-11-13

152

Differential Scanning Calorimetry and Evolved Gas Analysis of Hydromagnesite  

NASA Technical Reports Server (NTRS)

Volatile-bearing minerals (e.g., Fe-oxyhydroxides, phyllosilicates, carbonates and sulfates) may be important phases on the surface of Mars. In order to characterize these phases the Thermal and Evolved Gas Analyzer (TEGA) flying on the Mars'98 lander will perform analyses on surface samples from Mars. Hydromagnesite [Mg5(CO3)4(OH)2.4H2O] is considered a good standard mineral to examine as a Mars soil analog component because it evolves both H2O and CO2 at temperatures between 0 and 600 C. Our aim here is to interpret the DSC signature of hydromagnesite under ambient pressure and 20 sccm N2 flow in the range 25 to 600 C. The DSC curve for hydromagnesite under the above conditions consists of three endothermic peaks at temperatures 296, 426, and 548 and one sharp exotherm at 511 C. X-ray analysis of the sample at different stop temperatures suggested that the exotherm corresponded with the formation of crystalline magnesite. The first endotherm was due to dehydration of hydromagnesite, and then the second one was due to the decomposition of carbonate, immediately followed by the formation of magnesite (exotherm) and its decomposition to periclase (last endotherm). Evolution of water and CO2 were consistent with the observed enthalpy changes. A library of such DSC-evolved gas curves for putative Martian minerals are currently being acquired in order to facilitate the interpretation of results obtained by a robotic lander.

Lauer, H. V., Jr.; Golden, D. C.; Ming, Douglas W.; Boynton, W. V.

1999-01-01

153

Yeast SREBP cleavage activation requires the Golgi Dsc E3 ligase complex  

PubMed Central

SUMMARY Mammalian lipid homeostasis requires proteolytic activation of membrane-bound sterol regulatory element binding protein (SREBP) transcription factors through sequential action of the Golgi Site-1 and Site-2 proteases. Here, we report that while SREBP function is conserved in fungi, fission yeast employs a different mechanism for SREBP cleavage. Using genetics and biochemistry, we identified four genes defective for SREBP cleavage, dsc1–4, encoding components of a transmembrane Golgi E3 ligase complex with structural homology to the Hrd1 E3 ligase complex involved in endoplasmic reticulum-associated degradation. The Dsc complex binds SREBP and cleavage requires components of the ubiquitin-proteasome pathway: the E2 conjugating enzyme Ubc4, the Dsc1 RING E3 ligase and the proteasome. dsc mutants display conserved aggravating genetic interactions with components of the multivesicular body pathway in fission yeast and budding yeast, which lacks SREBP. Together, these data suggest that the Golgi Dsc E3 ligase complex functions in a post-ER pathway for protein degradation. PMID:21504829

Stewart, Emerson V.; Nwosu, Christine C.; Tong, Zongtian; Roguev, Assen; Cummins, Timothy D.; Kim, Dong-Uk; Hayles, Jacqueline; Park, Han-Oh; Hoe, Kwang-Lae; Powell, David W.; Krogan, Nevan J.; Espenshade, Peter J.

2011-01-01

154

DSC: software tool for simulation-based design of control strategies applied to wastewater treatment plants.  

PubMed

This paper presents a computer tool called DSC (Simulation based Controllers Design) that enables an easy design of control systems and strategies applied to wastewater treatment plants. Although the control systems are developed and evaluated by simulation, this tool aims to facilitate the direct implementation of the designed control system to the PC of the full-scale WWTP (wastewater treatment plants). The designed control system can be programmed in a dedicated control application and can be connected to either the simulation software or the SCADA of the plant. To this end, the developed DSC incorporates an OPC server (OLE for process control) which facilitates an open-standard communication protocol for different industrial process applications. The potential capabilities of the DSC tool are illustrated through the example of a full-scale application. An aeration control system applied to a nutrient removing WWTP was designed, tuned and evaluated with the DSC tool before its implementation in the full scale plant. The control parameters obtained by simulation were suitable for the full scale plant with only few modifications to improve the control performance. With the DSC tool, the control systems performance can be easily evaluated by simulation. Once developed and tuned by simulation, the control systems can be directly applied to the full-scale WWTP. PMID:21330730

Ruano, M V; Ribes, J; Seco, A; Ferrer, J

2011-01-01

155

Solubility diagrams in solvent-antisolvent systems by titration calorimetry  

Microsoft Academic Search

Isothermal titration calorimetry (ITC) has been used to develop a method to construct the solid-liquid equilibrium line in\\u000a ternary systems containing the solute to precipitate and an aqueous mixed solvent. The method consists in measuring the heat\\u000a of dissolution of a solid component (the solute) during successive additions of the liquid solvent. The cumulated heat, resulting\\u000a from the successive heat

M. H. Hamedi; J.-P. E. Grolier

2007-01-01

156

2H-solid state NMR and DSC study of isobutyric acid in mesoporous silica materials.  

PubMed

Solid state deuterium NMR has been used to study the molecular motion of d(6)-isobutyric acid (d(6)-iBA) in the pure (unconfined) state and confined in the cylindrical pores of two periodic mesoporous silica materials (MCM-41, pore size 3.3 nm and SBA-15, pore size 8 nm), and in a controlled pore glass (CPG-10-75, pore size ca. 10 nm). The line shape analysis of the spectra at different temperatures revealed three rotational states of the iBA molecules: liquid (fast anisotropic reorientation of the molecule), solid I (rotation of the methyl group) and solid II (no rotational motion on the time scale of the experiment). Transition temperatures between these states were determined from the temperature dependence of the fraction of molecules in these states. Whereas the solid I-solid II transition temperature is not affected by confinement, a significant lowering of the liquid-solid I transition temperature in the pores relative to the bulk acid was found for the three matrix materials, exhibiting an unusual dependence on pore size and pore morphology. Complementary DSC measurements on the same systems show that the rotational melting (solid I-liquid) of d(6)-iBA in the pores occurs at a temperature 20-45 K below the thermodynamic melting point. This finding indicated that the decoupling of rotational and translational degrees of freedom in phase transitions in confined systems previously found for benzene is not restricted to molecules with non-specific interactions, but represents a more general phenomenon. PMID:17487322

Vyalikh, A; Emmler, Th; Shenderovich, I; Zeng, Y; Findenegg, G H; Buntkowsky, G

2007-06-14

157

Human Desmocollin 1 (Dsc1) Is an Autoantigen for the Subcorneal Pustular Dermatosis Type of IgA Pemphigus  

Microsoft Academic Search

IgA pemphigus showing IgA anti-keratinocyte cell surface autoantibodies is divided into subcorneal pustular dermatosis (SPD) and intraepidermal neutrophilic IgA dermatosis (IEN) types. We previously showed by immunoblotting that IgA from some IgA pemphigus patients reacted with bovine desmocollins (Dsc), but not human Dsc. To determine the antigen for IgA pemphigus, we focused on conformation-dependent epitopes of Dsc, because sera of

Takashi Hashimoto; Chie Kiyokawa; Osamu Mori; Minoru Miyasato; Martyn A. J. Chidgey; David R. Garrod; Yasushi Kobayashi; Koji Komori; Ken Ishii; Masayuki Amagai; Takeji Nishikawa

1997-01-01

158

Preformulation studies of Zidovudine derivatives: Acid dissociation constants, differential scanning calorimetry, thermogravimetry, x-ray powder diffractometry and aqueous stability studies.  

PubMed

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

Raviolo, Mónica A; Briñón, Margarita C

2011-09-01

159

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

NASA Astrophysics Data System (ADS)

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 (?H) were observed as an effect of cross-linkage. An increase in acid adipic concentration produced an increase in Tonset and a decrease in ?H. pH and temperature. The cross-linked of banana starch produced granules more resistant during the pasting procedure.

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

2008-07-01

160

Crystallization kinetic of Sb-V2O5-TeO2 glasses investigated by DSC and their elastic moduli and Poisson's ratio  

NASA Astrophysics Data System (ADS)

Ternary tellurate glasses of the form xSb-(60-x)V2O5-40TeO2 (0?x?15 in mol%) were prepared by using the usual melt quenching method. Differential scanning calorimetry (DSC) at different heating rates (?) was used to thermal analyze and to gain more insight in to the thermal stability, glass forming tendency and so calorimetric behavior of the present glasses. The glass transition temperature (Tg), the temperature corresponding to the onset of crystallization (Tx) and also the crystallization temperature (TCr) were obtained at different heating rates, to estimate the key kinetic parameter of activation energy of crystallization (?E) by using different empirical formulas. Also some other thermal parameters such as thermal stability and glass forming tendency were determined. It was found that Tg, Tx and TCr increase with increase in Sb content and also with increase in heating rate. Moreover, Makishima-Makenzie's theory was employed to evaluate the Poisson's ratio and elastic moduli, indicating a strong relation between elastic properties and the structure of glass. From the mechanical and thermal data and also the values of oxygen molar volume ( V O *), it was founded that the glass systems can be divided in to "two compositional regions"; so, results indicate that glasses with 10?x?15 (especially for x=12) are more thermal stable and strong glasses, which make them as more useful and promising materials in technological advantages and device manufacturing.

Souri, Dariush

2015-01-01

161

Structural evolution of indomethacin particles upon milling: time-resolved quantification and localization of disordered structure studied by IGC and DSC.  

PubMed

The amorphization of indomethacin was induced by milling. The mass fraction of the amorphous phase in the drug milled for various time intervals was determined with differential scanning calorimetry (DSC). Because the surface fraction amorphized by milling can be much higher than the mass fraction, which can have a large impact on the powder properties, a method for quantification of surface fraction amorphized by milling using inverse gas chromatography (IGC) was developed. A calibration curve was constructed by mixing completely amorphous indomethacin (obtained after milling for 120 min) with various amounts of the initial crystalline sample. Linear part of the curve was then used to quantify the surface amorphous content of samples milled for different time intervals. Surface and mass amorphization kinetics were determined and fitted to a first-order model. It was found that the surface amorphization rate is an order of magnitude higher than the mass amorphization rate. Results confirmed that IGC is a sensitive method for detection and quantification of the fraction of amorphous surface of milled indomethacin powder. If suitably combined with other techniques, this method represents a relatively general approach for the localization and quantification of the surface amorphous fraction in crystalline substances that transform into amorphous ones upon intensive milling. PMID:20049752

Planinsek, Odon; Zadnik, Jernej; Kunaver, Matjaz; Srcic, Stane; Godec, Aljaz

2010-04-01

162

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 2: Arquitetura -Camada de Enlace * Pg. 1  

E-print Network

REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 2: Arquitetura - Camada de Enlace definida para a camada de rede; Organiza os dados recebidos da camada de rede em quadros (frames) a serem transmitidos na rede física (e vice-versa); Trata erros de transmissão; e Realiza controle de fluxo para

Cirne, Walfredo

163

Determining the main thermodynamic parameters of caffeine melting by means of DSC  

NASA Astrophysics Data System (ADS)

The temperature and enthalpy of the melting of caffeine, which are 235.5 ± 0.1°C and 19.6 ± 0.2 kJ/mol, respectively, are determined by DSC. The melting entropy and the cryoscopic constant of caffeine are calculated.

Agafonova, E. V.; Moshchenskii, Yu. V.; Tkachenko, M. L.

2012-06-01

164

Muscle contribution to elbow joint valgus stability Fang Lin, DSc,a,b,c  

E-print Network

Muscle contribution to elbow joint valgus stability Fang Lin, DSc,a,b,c Navjot Kohli, MD,d Sam stabilizer for elbow valgus stability, incorporating with the MUCL for all tested joint configurations. Our by several authors.19,32,33 However, little is known about the dynamic stability of the elbow joint--that is

Makhsous, Mohsen

165

Multispectral Image Compression Based on DSC Combined with CCSDS-IDC  

PubMed Central

Remote sensing multispectral image compression encoder requires low complexity, high robust, and high performance because it usually works on the satellite where the resources, such as power, memory, and processing capacity, are limited. For multispectral images, the compression algorithms based on 3D transform (like 3D DWT, 3D DCT) are too complex to be implemented in space mission. In this paper, we proposed a compression algorithm based on distributed source coding (DSC) combined with image data compression (IDC) approach recommended by CCSDS for multispectral images, which has low complexity, high robust, and high performance. First, each band is sparsely represented by DWT to obtain wavelet coefficients. Then, the wavelet coefficients are encoded by bit plane encoder (BPE). Finally, the BPE is merged to the DSC strategy of Slepian-Wolf (SW) based on QC-LDPC by deep coupling way to remove the residual redundancy between the adjacent bands. A series of multispectral images is used to test our algorithm. Experimental results show that the proposed DSC combined with the CCSDS-IDC (DSC-CCSDS)-based algorithm has better compression performance than the traditional compression approaches. PMID:25110741

Li, Jin; Xing, Fei; Sun, Ting; You, Zheng

2014-01-01

166

Multispectral image compression based on DSC combined with CCSDS-IDC.  

PubMed

Remote sensing multispectral image compression encoder requires low complexity, high robust, and high performance because it usually works on the satellite where the resources, such as power, memory, and processing capacity, are limited. For multispectral images, the compression algorithms based on 3D transform (like 3D DWT, 3D DCT) are too complex to be implemented in space mission. In this paper, we proposed a compression algorithm based on distributed source coding (DSC) combined with image data compression (IDC) approach recommended by CCSDS for multispectral images, which has low complexity, high robust, and high performance. First, each band is sparsely represented by DWT to obtain wavelet coefficients. Then, the wavelet coefficients are encoded by bit plane encoder (BPE). Finally, the BPE is merged to the DSC strategy of Slepian-Wolf (SW) based on QC-LDPC by deep coupling way to remove the residual redundancy between the adjacent bands. A series of multispectral images is used to test our algorithm. Experimental results show that the proposed DSC combined with the CCSDS-IDC (DSC-CCSDS)-based algorithm has better compression performance than the traditional compression approaches. PMID:25110741

Li, Jin; Xing, Fei; Sun, Ting; You, Zheng

2014-01-01

167

David J. Brenner, PhD, DSc Carl D. Elliston, MA  

E-print Network

David J. Brenner, PhD, DSc Carl D. Elliston, MA Index terms: Cancer screening Computed tomography Screening1 PURPOSE: To estimate the radiation-related cancer mortality risks associated with single methods. MATERIALS AND METHODS: The estimated dose to the lung or stomach from a single full-body CT

Brenner, David Jonathan

168

ESTIMATION OF HRW WHEAT HEAT DAMAGE BY DSC, CAPILLARY ZONE ELECTROPHORESIS, PHOTOACOUSTIC SPECTROSCOPY AND RHEOMETRY  

Technology Transfer Automated Retrieval System (TEKTRAN)

The effect of heat damage was estimated using Hard Red Winter (HRW) wheat varieties grown in Oklahoma. The testing was done on wheat kernels, flour, and isolated starch. Whole-wheat kernels were analyzed by Photoacoustic Spectroscopy (PAS). Flour was analyzed by DSC, Capillary Electrophoresis (CE...

169

Application of the DSC model for nonlinear analysis of reinforced concrete frames  

Microsoft Academic Search

A nonlinear finite element method with eight-noded isoparametric quadrilateral elements for concrete and two-noded elements for reinforcement was used to predict the behavior of reinforced concrete frame structures. The disturbed state concept (DSC) and the hierarchical single surface (HISS) plasticity model with the associated modified flow rule were used to characterize the constitutive behavior of concrete in both compression and

Amir Hoshang Akhaveissy; Chandrakant S. Desai

170

Isothermal Titration Calorimetry of Membrane Proteins – Progress and Challenges  

PubMed Central

Summary Integral membrane proteins, including G protein-coupled receptors (GPCR) and ion channels, mediate diverse biological functions that are crucial to all aspects of life. The knowledge of the molecular mechanisms, and in particular, the thermodynamic basis of the binding interactions of the extracellular ligands and intracellular effector proteins is essential to understand the workings of these remarkable nanomachines. In this review, we describe how isothermal titration calorimetry (ITC) can be effectively used to gain valuable insights into the thermodynamic signatures (enthalpy, entropy, affinity, and stoichiometry), which would be most useful for drug discovery studies, considering that more than 30% of the current drugs target membrane proteins. PMID:23747362

Rajarathnam, Krishna; Rösgen, Jörg

2013-01-01

171

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 4: Estudo de Caso -RPP/RNP * Pg. 1  

E-print Network

REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 4: Estudo de Caso - RPP/RNP * Pág. 1 3.3 REDE NACIONAL DE PESQUISA - RNP REDE PARAIBANA DE PESQUISA - RPP INTERNET ! Maior rede mundial de. REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 4: Estudo de Caso - RPP/RNP * Pág. 2 ! Sua

Cirne, Walfredo

172

Electrical conductivity, differential scanning calorimetry, X-ray diffraction, and 7Li nuclear magnetic resonance studies of n-C x H(2x+1)OSO3Li (x = 12, 14, 16, 18, and 20)  

NASA Astrophysics Data System (ADS)

Electrical conductivity (?), differential scanning calorimetry (DSC), and X-ray diffraction (XRD) measurements of n-C x H (2x+1) OSO 3Li (x= 12, 14, 16, 18, and 20) crystals were performed as a function of temperature. In addition, ?, DSC, and XRD observations of n-C x H (2x+1) OSO 3Na and n-C x H (2x+1) OSO 3K (x= 12, 14, 16, 18, and 20) crystals were carried out for comparison. DSC results of the salts revealed several solid-solid phase transitions with large entropy changes (?S). For n-C 18 H 37 OSO 3Li and n-C 20 H 41 OSO 3Li salts, each melting point produced a small ?S mp value compared with the total entropy change in the solid phases (?S tr1+?S tr2). Additionally, Li + ion diffusion was detected in the highest temperature solid phases. For K salts, larger ? values were detected for potassium alkylsulfates compared with those reported for alkyl carboxylate. 7Li NMR spectra of n-C 18 H 37 OSO 3Li crystals recorded in the low-temperature phase showed large asymmetry parameters, suggesting the Li + ions are localized at asymmetric sites in the crystals.

Hirakawa, Satoru; Morimoto, Yoshiaki; Honda, Hisashi

2014-11-01

173

The use of calorimetry in nuclear materials management  

SciTech Connect

A calorimeter is a device to measure evolved or adsorbed heat. For our purposes, the heat measured is that associated with radioactive decay and the unit of measurement is the watt. Each time an atom decays, energy is released and absorbed by the surroundings and heat generated. For each isotope, this heat is a constant related to the energy of the decay particles and the half-life of the isotope. A point which is often overlooked is that calorimetry is one of the oldest techniques known for measuring radioactivity. In 1903, Pierre Curie and A. Laborde used a twin microcalorimeter to determine that one gram of radium generates about 100 calories per hour. Several months later, Curie and Dewar used liquid oxygen and hydrogen to show that the amount of energy developed by radium and other radioactive elements did not depend on temperature. At that time, this observation was extremely important. It indicated that the nature of radioactivity is entirely different and cannot be compared with any known phenomena. In all other thermal processes known in physics and chemistry, the rate at which heat is developed changes with temperature. In 1942, Monsanto was asked by General Leslie Groves, Head of the Manhattan Project, to accept the responsibility for the chemistry and metallurgy of radioactive polonium. Late in 1943, two Monsanto scientists began a study of the half-life of polonium-210 using calorimetry.

Nutter, J.D.; O`Hara, F.A.; Rodenburg, W.W.

1996-07-01

174

The Pandora Software Development Kit for Particle Flow Calorimetry  

NASA Astrophysics Data System (ADS)

Pandora is a robust and efficient framework for developing and running pattern-recognition algorithms. It was designed to perform particle flow calorimetry, which requires many complex pattern-recognition techniques to reconstruct the paths of individual particles through fine granularity detectors. The Pandora C++ software development kit (SDK) consists of a single library and a number of carefully designed application programming interfaces (APIs). A client application can use the Pandora APIs to pass details of tracks and hits/cells to the Pandora framework, which then creates and manages named lists of self-describing objects. These objects can be accessed by Pandora algorithms, which perform the pattern-recognition reconstruction. Development with the Pandora SDK promotes the creation of small, re-usable algorithms containing just the kernel of a specific operation. The algorithms are configured via XML and can be nested to perform complex reconstruction tasks. As the algorithms only access the Pandora objects in a controlled manner, via the APIs, the framework can perform most book-keeping and memory-management operations. The Pandora SDK has been fully exploited in the implementation of PandoraPFA, which uses over 60 algorithms to provide the state of the art in particle flow calorimetry for ILC and CLIC.

Marshall, J. S.; Thomson, M. A.

2012-12-01

175

Calorimetry and viscometry of hydrous volcanic glasses applied to welding processes  

NASA Astrophysics Data System (ADS)

It has recently been recognized that the crossing of the glass transition has a large affect on syn- and post-eruptive processes (e.g. fragmentation and welding). The glass transition is a kinetic boundary between a liquid-like and solid-like mechanical response to stress and strain. The temperature interval across which it occurs depends on composition, thermal history and the timescale of the processes applied to the material under investigation. Welding of glass-bearing volcanic products occurs above the glass transition, in the region of ductile deformation, as a consequence of a relaxation process that induces deformation of the glass under its own weight. After the process is activated the rate at which it continues is controlled by other properties, such as viscosity, eta. In addition, it has been observed that resorption of water can accelerate welding [Sparks et al. (1999) J Geol Soc, 156: 217-225]. In order to examine the affect that water has upon the glass transition and the rheological properties of different compositions of glass, we have measured the viscosity and heat capacities of trachytic (Campi Flegrei, Italy) and basaltic glasses (Mt. Etna, Italy) containing up to 2.5 and 3.26 wt.% water, respectively. The hydrated samples were synthesised in a piston cylinder apparatus. Viscosity measurements were conducted using concentric cylinder and micropenetration techniques. Heat capacities were determined using differential scanning calorimetry (DSC), for a range of heating and cooling rates between 5 and 20 K/min, from which specific glass transition temperatures (Tg) were defined. Trachytic and basaltic dry glasses have similar Tg of approximately 700oC. As water content increases Tg decreases irrespective of glass composition and thermal history. The addition of 2.5 wt.% water to the trachytic glasses reduces Tg by between 277 and 294oC, depending on thermal history, while the addition of 3.26 wt.% to the basaltic glasses reduces Tg by between 218 and 239oC. Therefore the Tg of trachytic glass is more sensitive to the addition of water than that of basaltic glass. Viscosity determinations will allow us to quantify the rate at which welding occurs. Other hydrous glass compositions are also currently being investigated.

Giordano, D.; Nichols, A.; Dingwell, D.

2003-04-01

176

Online particle detection with Neural Networks based on topological calorimetry information  

NASA Astrophysics Data System (ADS)

This paper presents the latest results from the Ringer algorithm, which is based on artificial neural networks for the electron identification at the online filtering system of the ATLAS particle detector, in the context of the LHC experiment at CERN. The algorithm performs topological feature extraction using the ATLAS calorimetry information (energy measurements). The extracted information is presented to a neural network classifier. Studies showed that the Ringer algorithm achieves high detection efficiency, while keeping the false alarm rate low. Optimizations, guided by detailed analysis, reduced the algorithm execution time by 59%. Also, the total memory necessary to store the Ringer algorithm information represents less than 6.2 percent of the total filtering system amount.

Ciodaro, T.; Deva, D.; de Seixas, J. M.; Damazio, D.

2012-06-01

177

Simulation and Analysis of Differential Scanning Calorimetry Output: Protein Unfolding Studies  

NASA Astrophysics Data System (ADS)

High sensitivity differential scanning calorimetry ( HSDSC ) is a powerful and increasingly used technique for the study of molecular energetics in relation to biopolymers (e.g. proteins and nucleic acids ) or biomacromolecular assemblies ( e.g. liposomes ). HSDSC is, for example, the only method which allows thermodynamic parameters to be obtained directly for protein unfolding. The thermodynamic basis for HSDSC signals obtained for the equilibrium unfolding of proteins as well as the formalism for generating simulations of HSDSC outputs for protein unfolding are discussed. This will allow students ( studying biophysical chemistry, biochemistry, biophysics, molecular biology and allied subjects at undergraduate and postgraduate level ) to obtain an understanding of the type of data analysis required for HSDSC experiments on proteins.

Chowdhry, Babur; Leharne, Stephen

1997-02-01

178

Thermodynamic properties of aqueous PEO-PPO-PEO micelles with added methylparaben determined by differential scanning calorimetry.  

PubMed

DSC experiments were performed on aqueous solutions of PEO-PPO-PEO (P105) amphiphiles in the low concentration regime (0-1%) to resolve the critical micelle concentration (cmc) both neat and co-formulated with methylparaben (MP). Further work was done at 10% amphiphilic copolymer concentrations and co-formulated with MP to resolve the variations in enthalpy. The compensation temperature, T(compensation), was determined from the analyses for neat P105 as 293.9 K; adding MP raises this to 328.43 K. PMID:23474225

Thompson, Andre Lamont; Love, Brian James

2013-05-15

179

Heat capacity of alkanolamines by differential scanning calorimetry  

SciTech Connect

Measurements of the heat capacities of the alkanolamines monoethanolamine, diethanolamine, diglycolamine, di-2-propanolamine, triethanolamine, N-methyldiethanolamine, 2-amino-2-methyl-l-propanol, and 2-piperidineethanol were performed from 30 to 80 C with a differential scanning calorimeter (DSC). The heat capacity of liquid water has been measured to verify the validity of the C{sub p} measurements. The measured C{sub p} of each alkanolamine has been expressed as a function of temperature. The estimated uncertainty of the measured heat capacities including the effect of impurities in a substance with a purity of 95% is {+-}3%. The measured heat capacities are, in general, of sufficient accuracy for most engineering-design calculations.

Chiu, L.F.; Liu, H.F.; Li, M.H. [Chung Yuan Christian Univ., Chung Li (Taiwan, Province of China). Dept. of Chemical Engineering] [Chung Yuan Christian Univ., Chung Li (Taiwan, Province of China). Dept. of Chemical Engineering

1999-05-01

180

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

SciTech Connect

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''.

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

2001-12-31

181

Direct Animal Calorimetry, the Underused Gold Standard for Quantifying the Fire of Life*  

PubMed Central

Direct animal calorimetry, the gold standard method for quantifying animal heat production (HP), has been largely supplanted by respirometric indirect calorimetry owing to the relative ease and ready commercial availability of the latter technique. Direct calorimetry, however, can accurately quantify HP and thus metabolic rate (MR) in both metabolically normal and abnormal states, whereas respirometric indirect calorimetry relies on important assumptions that apparently have never been tested in animals with genetic or pharmacologically-induced alterations that dysregulate metabolic fuel partitioning and storage so as to promote obesity and/or diabetes. Contemporary obesity and diabetes research relies heavily on metabolically abnormal animals. Recent data implicating individual and group variation in the gut microbiome in obesity and diabetes raise important questions about transforming aerobic gas exchange into HP because 99% of gut bacteria are anaerobic and they outnumber eukaryotic cells in the body by ~10-fold. Recent credible work in non-standard laboratory animals documents substantial errors in respirometry-based estimates of HP. Accordingly, it seems obvious that new research employing simultaneous direct and indirect calorimetry (total calorimetry) will be essential to validate respirometric MR phenotyping in existing and future pharmacological and genetic models of obesity and diabetes. We also detail the use of total calorimetry with simultaneous core temperature assessment as a model for studying homeostatic control in a variety of experimental situations, including acute and chronic drug administration. Finally, we offer some tips on performing direct calorimetry, both singly and in combination with indirect calorimetry and core temperature assessment. PMID:20427023

Kaiyala, Karl J.; Ramsay, Douglas S.

2012-01-01

182

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 3: TCP/IP -Introduo * Pg. 1  

E-print Network

REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 3: TCP/IP - Introdução * Pág. 1 uma rede experimental de comutação de pacotes ­ ARPANET ­ que deveria prover: robustez; confiabilidade de um protocolo para interconexão de redes; ! 1980, TCP/IP torna-se padrão na ARPANET; ! 1983, TCP

Cirne, Walfredo

183

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 4: Estudo de Caso -UFPB * Pg. 1  

E-print Network

REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 4: Estudo de Caso - UFPB * Pág. 1 3.2 REDE DA UNIVERSIDADE FEDERAL DA PARAÍBA - UFPB-NET PREMISSAS BÁSICAS ! As redes de comunicação de dados a cargo de cada departamento/núcleo/setor a organização de sua rede interna; definição de uma espinha

Cirne, Walfredo

184

REDES DE COMPUTADORES UFPB / CCT / DSC / PSN, 2001 * Parte 2: Arquitetura -Camada de Transporte * Pg. 1  

E-print Network

REDES DE COMPUTADORES © UFPB / CCT / DSC / PSN, 2001 * Parte 2: Arquitetura - Camada de Transporte * Pág. 1 2.4 A CAMADA DE TRANSPORTE ! O nível de transporte é o coração da pilha de protocolos. Sua tarefa é prover transporte confiável e eficiente de dados de uma máquina origem para uma máquina destino

Cirne, Walfredo

185

Comparison of the Degree of Conversion of Resin Based Endodontic Sealers Using the DSC Technique  

PubMed Central

Objectives: The aim of this study was to determine the degree of conversion (DC) of three resin based endodontic sealers using the DSC technique. Methods: The sealers tested were: EndoREZ (ER) (Ultradent, South Jordan, UT); EndoREZ with Accelerator (ER+A) (Ultradent, South Jordan, UT); RealSeal (RS) (SybronEndo, Orange, CA). Two LED units were used to activate the sealers: UltraLume LED 5 (Ultradent, South Jordan, UT, USA); Mini LED Satelec (Satelec Acteon Group, Mérignac Cedex, France). Samples of 4.0 mg were analyzed with a DSC 7 calorimeter (Perkin Elmer Inc., Wellesley, MA, US). Each specimen was irradiated by each lamp four times for 20 seconds at an interval of 2 mins, while the DSC 7 recorded the heat flow developed during the treatment. The degree of conversion and the kinetic curves were calculated from the values of heat developed during each polymerization. The data were statistically analysed with a Kruskal-Wallis one-way ANOVA multiple range and Student-Newman-Keuls (SNK) tests at a P value of .05. Results: Statistically significant differences were found in the degree of conversion among the sealers: ER+A showed the highest values with both lamps. Conclusions: The higher polymerization rate in resin sealers is obtained with the addition of a catalyst. PMID:21494378

Cotti, Elisabetta; Scungio, Paola; Dettori, Claudia; Ennas, Guido

2011-01-01

186

Enzymatic activity of immobilized enzyme determined by isothermal titration calorimetry.  

PubMed

The activity of adsorbed beta-glucosidase onto spherical polyelectrolyte brushes (SPBs) is investigated by UV-Vis spectroscopy and isothermal titration calorimetry (ITC). By comparing the results of these two methods, we demonstrate that ITC is a precise method for the study of the activity of immobilized enzymes. The carrier particles used for immobilization here consist of a polystyrene core onto which poly(acrylic acid) chains are grafted. High amounts of enzyme can be immobilized in the brush layer at low ionic strength by the polyelectrolyte-mediated protein adsorption (PMPA). Analysis of the activity of beta-glucosidase was done in terms of Michaelis-Menten kinetics. Moreover, the enzymatic activity of immobilized enzyme is studied by ITC using cellobiose as substrate. All data show that ITC is a general method for the study of the activity of immobilized enzymes. PMID:18440294

Henzler, Katja; Haupt, Björn; Ballauff, Matthias

2008-07-15

187

Hydroxylamine nitrate self-catalytic kinetics study with adiabatic calorimetry.  

PubMed

Hydroxylamine nitrate (HAN) is an important member of the hydroxylamine compound family with applications that include equipment decontamination in the nuclear industry and aqueous or solid propellants. Due to its instability and autocatalytic behavior, HAN has been involved in several incidents at the Hanford and Savannah River Site (SRS) [Technical Report on Hydroxylamine Nitrate, US Department of Energy, 1998]. Much research has been conducted on HAN in different areas, such as combustion mechanism, decomposition mechanism, and runaway behavior. However, the autocatalytic decomposition behavior of HAN at runaway stage has not been fully addressed due to its highly exothermic and rapid decomposition behavior. This work is focused on extracting HAN autocatalytic kinetics and analyzing HAN critical behavior from adiabatic calorimetry measurements. A lumped autocatalytic kinetic model for HAN and associated model parameters are determined. Also the storage and handling critical conditions of diluted HAN solution without metal presence are quantified. PMID:18639378

Liu, Lijun; Wei, Chunyang; Guo, Yuyan; Rogers, William J; Sam Mannan, M

2009-03-15

188

Use of thermal analysis techniques (TG-DSC) for the characterization of diverse organic municipal waste streams to predict biological stability prior to land application  

SciTech Connect

Highlights: Black-Right-Pointing-Pointer Thermal analysis was used to assess stability and composition of organic matter in three diverse municipal waste streams. Black-Right-Pointing-Pointer Results were compared with C mineralization during 90-day incubation, FTIR and {sup 13}C NMR. Black-Right-Pointing-Pointer Thermal analysis reflected the differences between the organic wastes before and after the incubation. Black-Right-Pointing-Pointer The calculated energy density showed a strong correlation with cumulative respiration. Black-Right-Pointing-Pointer Conventional and thermal methods provide complimentary means of characterizing organic wastes. - Abstract: The use of organic municipal wastes as soil amendments is an increasing practice that can divert significant amounts of waste from landfill, and provides a potential source of nutrients and organic matter to ameliorate degraded soils. Due to the high heterogeneity of organic municipal waste streams, it is difficult to rapidly and cost-effectively establish their suitability as soil amendments using a single method. Thermal analysis has been proposed as an evolving technique to assess the stability and composition of the organic matter present in these wastes. In this study, three different organic municipal waste streams (i.e., a municipal waste compost (MC), a composted sewage sludge (CS) and a thermally dried sewage sludge (TS)) were characterized using conventional and thermal methods. The conventional methods used to test organic matter stability included laboratory incubation with measurement of respired C, and spectroscopic methods to characterize chemical composition. Carbon mineralization was measured during a 90-day incubation, and samples before and after incubation were analyzed by chemical (elemental analysis) and spectroscopic (infrared and nuclear magnetic resonance) methods. Results were compared with those obtained by thermogravimetry (TG) and differential scanning calorimetry (DSC) techniques. Total amounts of CO{sub 2} respired indicated that the organic matter in the TS was the least stable, while that in the CS was the most stable. This was confirmed by changes detected with the spectroscopic methods in the composition of the organic wastes due to C mineralization. Differences were especially pronounced for TS, which showed a remarkable loss of aliphatic and proteinaceous compounds during the incubation process. TG, and especially DSC analysis, clearly reflected these differences between the three organic wastes before and after the incubation. Furthermore, the calculated energy density, which represents the energy available per unit of organic matter, showed a strong correlation with cumulative respiration. Results obtained support the hypothesis of a potential link between the thermal and biological stability of the studied organic materials, and consequently the ability of thermal analysis to characterize the maturity of municipal organic wastes and composts.

Fernandez, Jose M., E-mail: joseman@sas.upenn.edu [Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104-6316 (United States); Plaza, Cesar; Polo, Alfredo [Instituto de Ciencias Agrarias, Consejo Superior de Investigaciones Cientificas, Serrano 115 dpdo., 28006 Madrid (Spain); Plante, Alain F. [Department of Earth and Environmental Science, University of Pennsylvania, Philadelphia, PA 19104-6316 (United States)

2012-01-15

189

Gelatinisation of starch: a combined SAXS\\/WAXS\\/DSC and SANS study  

Microsoft Academic Search

Using a combination of techniques, small- and wide-angle X-ray scattering, differential scanning calorimetry and small-angle neutron scattering, it has been possible to follow the stages that occur during gelatinisation in excess water for a range of starches. It is found that water enters the amorphous growth rings first, and that this is where all the swelling is concentrated. The periodicity

Paul J Jenkins; Athene M Donald

1998-01-01

190

Isothermal titration calorimetry study of a bistable supramolecular system: reversible complexation of cryptand[2.2.2] with potassium ions.  

PubMed

Isothermal titration calorimetry (ITC) is used to investigate the thermodynamics of the complexation of potassium ions by 1,10-diaza-4,7,13,16,21,24-hexaoxabicyclo[8.8.8]hexacosane (cryptand[2.2.2]) in aqueous solution. By changing the pH of the solution it was possible to trigger the reversible complexation/decomplexation of the cryptand in consecutive in situ experiments and to assess for the first time the use of ITC to monitor the thermodynamics of a bistable system. PMID:24986754

del Rosso, Maria G; Ciesielski, Artur; Colella, Silvia; Harrowfield, Jack M; Samorì, Paolo

2014-09-15

191

Questions and comments -Prof. RNDr. Josef Mlek, DSc., CSc. Jak se v modelovn resp. ve formulaci modelu ci v odvozen algoritmu projev  

E-print Network

Questions and comments - Prof. RNDr. Josef Málek, DSc., CSc. Question 1 Jak se v modelování resp continuum). + divs - b 0 #12;Questions and comments - Prof. RNDr. Josef Málek, DSc., CSc. Question 1 Jak (single continuum). + div q T - b 0 #12;Questions and comments - Prof. RNDr. Josef Málek, DSc., CSc

Cerveny, Vlastislav

192

Ultra-sensitive Calorimetry for Microwave Cyclotron Resonance in a Two-Dimensional Electron Gas  

E-print Network

GP-B-1 Ultra-sensitive Calorimetry for Microwave Cyclotron Resonance in a Two-dimensional electron in GaAs quantum wells. We construct a differential nano-calorimetry which can operate at 300 mK the sensitivity for detecting CR heating to several nano-watts. This ultra-sensitive technique opens up

193

The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition  

E-print Network

The energy density of jellyfish: Estimates from bomb-calorimetry and proximate-composition Thomas K scyphozoan jellyfish (Cyanea capillata, Rhizostoma octopus and Chrysaora hysoscella). First, bomb). These proximate data were subsequently converted to energy densities. The two techniques (bomb- calorimetry

Hays, Graeme

194

Temperature-modulated differential scanning calorimetry as a specific heat spectroscopy  

Microsoft Academic Search

The ability of modulated differential scanning calorimetry (MDSC) technique to perform a specific heat spectroscopy is examined by comparing MDSC results with those of alternating current calorimetry technique. The comparison is performed on three glass formers: glycerol, propylene glycol and salol. Both techniques give rise to similar activation energies, fragility index m and non-exponential parameters beta for the different compounds.

L. Carpentier; O. Bustin; M. Descamps

2002-01-01

195

Morphology of blends of linear and long-chain-branched polyethylenes in the solid state: A study by SANS, SAXS, and DSC  

SciTech Connect

Differential scanning calorimetry (DSC), small-angle neutron scattering (SANS), and X-ray scattering (SAXS) have been used to investigate the solid-state morphology of blends of linear (high density) and long-chain-branched (low-density) polyethylenes (HDPE/LDPE). The blends are homogeneous in the melt, as previously demonstrated by SANS using the contrast obtained by deuterating the linear polymer. However, due to the structural and melting point differences ({approximately} 20 C) between HDPE and LDPE, the components may phase segregate on slow cooling (0.75 C/min). For high concentrations ({phi} {ge} 0.5) of HDPE, relatively high rates of crystallization of the linear component lead to the formation of separate stacks of HDPE and LDPE lamellae, as indicated by two-peak SAXS curves. For predominantly branched blends, the difference in crystallization rate of the components becomes smaller and only one SAXS peak is observed, indicating that the two species are in the same lamellar stack. Moreover, the phases no longer consist of the pure component and the HDPE lamellae contain up to 15--20% LDPE (and vice versa). Rapid quenching into dry ice/2-propanol ({minus}78 C) produces only one SAXS peak (and hence one lamellar stack) over the whole concentration range. The blends show extensive cocrystallization, along with a tendency for the branched material to be preferentially located in the amorphous interlamellar regions. For high concentrations ({phi} > 0.5) of HDPE-D, the overall scattering length density (SLD) is high and the excess concentration of LDPE between the lamellae enhances the SLD contrast between the crystalline and amorphous phases. Thus, the interlamellar spacing (long period) is clearly visible in the SANS pattern. The blend morphology is a strong function of the quenching rate, and samples quenched less rapidly (e.g., into water at 23 C) are similar to slowly cooled blends.

Wignall, G.D.; Londono, J.D.; Lin, J.S. [Oak Ridge National Lab., TN (United States); Alamo, R.G.; Galante, M.J.; Mandelkern, L. [Florida State Univ., Tallahassee, FL (United States)

1995-04-24

196

DSC enthalpy of vaporization measurements of high temperature two-phase working fluids  

Microsoft Academic Search

The enthalpies of vaporization, saturated pressure-temperature behavior, and melting points for high-temperature (300–400°C) two-phase working fluids were measured using high-pressure DSC methodologies similar to those currently under development by ASTM E37. The materials, biphenyl, decafluorobiphenyl, o-terphenyl, naphthalene, quinoline, and perfluoro-1,3,5-triphenyl-benzene, were studied at seven pressures between 50 kPa and 1.4 MPa. The experimental measurements employed the use of a Mettler

Dwight D. Back; Lawrence R. Grzyll; Mary Corrigan

1996-01-01

197

DSC and Raman spectra of ? and ?-Endosulfan plus 60/40 mixture  

NASA Astrophysics Data System (ADS)

The symmetrical ?-conformer of endosulfan has the identical chemical composition of the asymmetrical ?-conformer, and both have very different melting/boiling points. The ?- and ?-isomer however have markedly different Raman spectra at each of 50°C, 75°C and 100°C. Moreover, the commercially available Raman spectra of the 60/40 (?-/?-) mixture at the same temperatures is discrete from either a- and b-isomer alone. Previous research demonstrated that at a- boiling point 110°C, ?-conformer partially converts to ?-. DSC curves of mixtures suggest thermal interactions and conformational changes occurs in BOTH ?- and ?-isomer at temperatures even 60°C lower than the liquid/gas phase transition.

Schmidt, Walter F.; Nguyen, Julie K.; Qin, Jianwei; Kim, Moon S.; Mookherji, Swati; McConnell, Laura L.; Hapeman, Cathleen J.

2013-05-01

198

Characterization of membrane protein interactions by isothermal titration calorimetry.  

PubMed

Understanding the structure, folding, and interaction of membrane proteins requires experimental tools to quantify the association of transmembrane (TM) helices. Here, we introduce isothermal titration calorimetry (ITC) to measure integrin ?IIb?3 TM complex affinity, to study the consequences of helix-helix preorientation in lipid bilayers, and to examine protein-induced lipid reorganization. Phospholipid bicelles served as membrane mimics. The association of ?IIb?3 proceeded with a free energy change of -4.61±0.04kcal/mol at bicelle conditions where the sampling of random helix-helix orientations leads to complex formation. At bicelle conditions that approach a true bilayer structure in effect, an entropy saving of >1kcal/mol was obtained from helix-helix preorientation. The magnitudes of enthalpy and entropy changes increased distinctly with bicelle dimensions, indicating long-range changes in bicelle lipid properties upon ?IIb?3 TM association. NMR spectroscopy confirmed ITC affinity measurements and revealed ?IIb?3 association and dissociation rates of 4500±100s(-1) and 2.1±0.1s(-1), respectively. Thus, ITC is able to provide comprehensive insight into the interaction of membrane proteins. PMID:25178257

Situ, Alan J; Schmidt, Thomas; Mazumder, Parichita; Ulmer, Tobias S

2014-10-23

199

A Common Origin for Cosmic Explosions Inferred from Fireball Calorimetry  

E-print Network

Past studies suggest that long-duration gamma-ray bursts (GRBs) have a standard energy of E_gamma ~ 10^51 erg in ultra-relativistic ejecta when corrected for asymmetry ("jets"). However, recently a group of sub-energetic bursts, including the peculiar GRB 980425 associated with SN 1998bw (E_gamma ~ 10^48 erg), has been identified. Here we report radio observations of GRB 030329, the nearest burst to date, which allow us to undertake calorimetry of the explosion. Our observations require a two-component explosion: a narrow (5 degrees) ultra-relativistic component responsible for the gamma-rays and early afterglow, and a wide, mildly relativistic component responsible for the radio and optical afterglow beyond 1.5 days. While the gamma-rays are energetically minor, the total energy release, dominated by the wide component, is similar to that of other GRBs. Given the firm link of GRB 030329 with SN 2003dh our result suggests a common origin for cosmic explosions in which, for reasons not understood, the energy in the highest velocity ejecta is highly variable

E. Berger; S. R. Kulkarni; G. Pooley; D. A. Frail; V. McIntyre; R. M. Wark; R. Sari; A. M. Soderberg; D. W. Fox; S. A. Yost; P. A. Price

2003-08-11

200

High resolution optical calorimetry for synchrotron microbeam radiation therapy  

NASA Astrophysics Data System (ADS)

We propose the application of optical calorimetry to measure the peak to valley ratio for synchrotron microbeam radiation therapy (MRT). We use a modified Schlieren approach known as reference image topography (RIT) which enables one to obtain a map of the rate of change of the refractive index in a water bath from which the absorbed dose can be determined with sufficient spatial accuracy to determine the peak to valley ratio. We modelled the calorimetric properties of X-rays using a heated wire in a water bath. Our RIT system comprised a light source, a textured reference object and a camera and lens combination. We measured temperature contours and showed a plume rising from the heated wire. The total temperature change in water was 12 degrees C, 500 times greater than the calculated change from a 1 ms exposure on a synchrotron. At 1.0 ms, thermal diffusion will be the major cause of uncertainty in determining the peak to valley ratio, and we calculate thermal diffusion will reduce the measured peak to valley ratio to 76% of its initial value, but the individual microbeams will still resolve. We demonstrate proof of concept for measuring X-ray dose using a modified RIT method.

Ackerly, T.; Crosbie, J. C.; Fouras, A.; Sheard, G. J.; Higgins, S.; Lewis, R. A.

2011-03-01

201

Calorimetry study of microwave absorption of some solid materials.  

PubMed

In practice, the dielectric constant of a material varies the applied frequency the material composition, particle size, purity, temperature, physical state (solid or liquid), and moisture content. All of these parameters might change during processing, therefore, it is difficult to predict how well a material will absorb microwave energy in a given process. When the temperature is measured by a digital thermometer, it could not accurately reflect the true temperature of the bulk materials, especially for mixed materials. Thus, in this paper we measured the microwave absorption characteristics of different materials by calorimetry. The microwave power levels, irradiation times, and masses of the materials were varied. It was difficult to predict the microwave energy absorption characteristics of reagent-grade inorganic compounds based on their color, metallic cation, or water stoichiometry. CuO, MnO2, Fe3O4, and MnSO4 x H2O (Taishan) strongly absorbed microwave energy. Most of the remaining inorganic compounds were poor absorbers, with silica hardly absorbing any microwave energy. Carbon-based materials had significantly different microwave absorption characteristics. Activated carbon and coke were especially sensitive to microwaves, but different types of coal were poor absorbers. The jamesonite concentrate absorbed microwave energy strongly, while the zinc concentrate was a poor absorber. PMID:24779227

He, Chun Lin; Ma, Shao Jian; Su, Xiu Juan; Chen, Yan Qing; Liang, Yu Shi

2013-01-01

202

Academic genealogy and direct calorimetry: a personal account.  

PubMed

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 who were all major figures in their day. The striking aspect, however, is that of the 14 individuals discussed, including myself, 10 individuals used the technique of direct calorimetry to study metabolic heat production in humans or other animals. Indeed, the patriarchs of my PhD genealogy, Antoine Lavoisier and Pierre Simon Laplace, were the inventors of this technique and the first to use it in animal studies. Brief summaries of the major accomplishments of each my scientific ancestors are given followed by a discussion of the variety of calorimeters and the scientific studies in which they were used. Finally, readers are encouraged to explore their own academic legacies as a way of honoring those who prepared the way for us. PMID:21652494

Jackson, Donald C

2011-06-01

203

Thermal properties and mixing state of ethylene glycol-water binary solutions by calorimetry, large-angle X-ray scattering, and small-angle neutron scattering.  

PubMed

Thermal properties and mixing states of ethylene glycol (EG)-water binary solutions in the entire mole fraction range of EG, 0 < or = x(EG) < or = 1, have been clarified by using differential scanning calorimetry (DSC), large-angle X-ray scattering (LAXS), and small-angle neutron scattering (SANS) techniques. The DSC curves obtained have shown that the EG-water solutions over the range of EG mole fraction 0.3 < or = x(EG) < or = 0.5 are kept in the supercooling state until approximately 100 K, and those in the range of 0.6 < or = x(EG) < or = 0.8 are vitrified, and those in the ranges of 0 < x(EG) < or = 0.2 and 0.9 < or = x(EG) < 1 are crystallized. The radial distribution function (RDF) for pure EG obtained from the LAXS measurements has suggested that a gauche conformation of an EG molecule is favorable in the liquid. The RDFs for the EG-water solutions have shown that the structure of the binary solutions moderately changes from the inherent structure of EG to the tetrahedral-like structure of water when the water content increases. The SANS intensities for deuterated ethylene glycol (HOCD2CD2OH) (EGd4)-water solutions at x(EG) = 0.4 and 0.6 have not been significantly observed in the temperature range from 298 to 173 K, showing that EG and water molecules are homogeneously mixed. On the other hand, the SANS intensities at x(EG) = 0.2 and 0.9 have been strengthened when the temperature decreases due to crystallization of the solutions. On the basis of all the present results, a relation between thermal properties of EG-water binary solutions and their mixing states clarified by the LAXS and SANS measurements has been discussed at the molecular level. PMID:16800561

Matsugami, Masaru; Takamuku, Toshiyuki; Otomo, Toshiya; Yamaguchi, Toshio

2006-06-29

204

Aggregation property of glycyrrhizic acid and its interaction with cyclodextrins analyzed by dynamic light scattering, isothermal titration calorimetry, and NMR.  

PubMed

The structural properties of glycyrrhizic acid, a sweet-tasting constituent of Glycyrrhiza glabra, and its interaction with cyclodextrins were analyzed using dynamic light scattering, isothermal titration calorimetry, and NMR. The dynamic light scattering and NMR studies showed that glycyrrhizic acid forms a water-soluble aggregate that disperses upon the addition of ?-cyclodextrin. The high sweetness of glycyrrhizic acid can be closely correlated with this aggregation, because the multimers of glycyrrhizic acid can simultaneously bind to the sweet taste receptors on the human tongue. The isothermal titration calorimetry experiments demonstrated that ?-cyclodextrin binds to glycyrrhizic acid more strongly than ?-cyclodextrin, however, both reactions are accompanied by a favorable change in binding entropy. Considering the large negative change in heat capacity that is observed during the binding of ?-cyclodextrin, the main driving force for the binding is hydrophobic interactions with dehydration, which is typical for inclusion complex. NMR experiments showed that ?-cyclodextrin interacts with the central part of the aglycone moiety, not the glucuronic acid moieties, resulting in high binding affinity. It should also be noted that the two distinct complexes of glycyrrhizic acid with ?-cyclodextrin would exist in aqueous solution. PMID:24844630

Izutani, Yusuke; Kanaori, Kenji; Oda, Masayuki

2014-06-17

205

Thermodynamics of ion binding to phosphatidic acid bilayers. Titration calorimetry of the heat of dissociation of DMPA.  

PubMed

The heat of dissociation of the second proton of 1,2-dimyristoylphosphatidic acid (DMPA) was studied as a function of temperature using titration calorimetry. The dissociation of the second proton of DMPA was induced by addition of NaOH. From the calorimetric titration experiment, the intrinsic pK0 for the dissociation reaction could be determined by applying the Gouy-Chapman theory. pK0 decreases with temperature from ca. 6.2 at 11 degrees C to 5.4 at 54 degrees C. From the total heat of reaction, the dissociation enthalpy, delta Hdiss, was determined by subtracting the heat of neutralization of water and the heat of dilution of NaOH. In the temperature range between 2 and 23 degrees C, delta Hdiss is endothermic with an average value of ca. 2.5 kcal.mol-1 and shows no clear-cut temperature dependence. In the temperature range between 23 and 52 degrees C, delta Hdiss calculated after subtraction of the heat of neutralization and dilution is not the true dissociation enthalpy but includes contributions from the phase transition enthalpy, delta Htrans, as the pH jump induces a transition from the gel to the liquid-crystalline phase. The delta Cp for the reaction enthalpy observed in this temperature range is positive. Above 53 degrees C, the pH jump induces again only the dissociation of the second proton, and the bilayers stay in the liquid-crystalline phase. In this temperature range, delta Hdiss seems to decrease with temperature. The thermodynamic data from titration calorimetry and differential scanning calorimetry as a function of pH can be combined to construct a complete enthalpy-temperature diagram of DMPA in its two ionization states. PMID:1316155

Blume, A; Tuchtenhagen, J

1992-05-19

206

Thermal and electrical characterization of a micro-hotplate for calorimetry  

E-print Network

This thesis characterizes a micro-hotplate designed at Draper Laboratory. This hotplate will be integrated into a calorimetry system that measures the heat released or absorbed by a reaction. An analytical thermal model ...

Baliga, Radhika

2004-01-01

207

Calorimetry exchange program amendment to 3rd quarter CY92 report LLNL isotopic data  

SciTech Connect

This report is a series of ammendments to the Calorimetry Exchange Quarterly Data Report for third quarter CY1992. The ammendment is needed due to reporting errors encountered in the Lawrence Livermore National Laboratory isotopic data.

Barnett, T.M.

1996-08-01

208

Proceedings of the Eleventh International Conference on Calorimetry in Particle Physics  

NASA Astrophysics Data System (ADS)

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 primitive generation / N. Regnault -- Optical data links for the CMS ECAL / J. Grahl (contribution not received) -- CMS ECAL off-detector electronics / R. Alemany Fernandez -- Performance of a low noise readout ASIC for the W-Si calorimeter physics prototype for the future linear collider / C. de la Taille -- Properties of a sampling calorimeter with warm-liquid ionization chambers / S. Plewnia -- Calorimetry and the DO experiment / R. Zitoun (contribution not received) -- Data quality monitoring for the DØ calorimeter / V. Shary -- Status of the construction of the ATLAS electromagnetic liquid argon calorimeter, overview of beam test performance studies / L. Serin -- Uniformity of response of ATLAS liquid argon EM calorimeter / O. Gaunter -- Status of the ATLAS liquid argon hadronic endcap calorimeter construction / M. Vincter -- Results from particle beam tests of the ATLAS liquid argon endcap calorimeters / M. Lefebvre -- First results of the DREAM project / R. Wigmans -- Electron and muon detection with a dual-readout (DREAM) calorimeter / N. Akchurin -- The neutron zero degree calorimeter for the ALICE experiment / M. Gallio -- The liquid xenon scintillation calorimeter of the MEG experiment: operation of a large prototype / G. Signorelli -- Detection of high energy particles using radio frequency signals / C. Hebert -- Hadronic shower simulation / J.-P. Wellisch -- E.M. and hadronic shower simulation with FLUKA / G. Battistoni -- Simulation of the LHCb electromagnetic calorimeter response with GEANT4 / P. Robbe -- Comparison of beam test results of the combined ATLAS liquid argon endcap calorimeters with GEANT3 and GEANT4 simulations / D. Salihagi? -- GEANT4 hadronic physics validation with LHC test-beam data / C. Alexa -- The full simulation of the GLAST LAT high energy gamma ray telescope / F. Longo -- Response of the KLOE electromagnetic calorimeter to low-energy particles / T. Spadaro -- Calorimeter algorithms for DØ; / S. Trincaz-Duvoid -- Identification of low P[symbol] muon with the ATLAS tile calorimeter / G. Usai -- Electron and photon reconstruction

Cecchi, Claudia

209

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

PubMed Central

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 <10?8 M), a new challenge arises: to measure these values accurately. Isothermal 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

Aweda, Tolulope A.; Meares, Claude F.

2011-01-01

210

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

PubMed

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. PMID:25484232

Pethica, Brian A

2015-03-01

211

Experiments  

NASA Astrophysics Data System (ADS)

Experiments were performed on the CERN cyclotron. Pion capture in Ta, Re, and Bi, quadrupole moments, nuclear gamma transitions, pion absorption in the nucleus, neutron multiplicity and angular momentum, and charged particles emission after pion absorption were studied.

Konijn, J.

212

Glass Transition in CO2 Treated Polysulfones by DSC and PAS  

NASA Astrophysics Data System (ADS)

Sub-nanometer hole structures in polymers at the molecular level are important for gas separation, membrane properties, and coating applications. The change in these properties due to gas exposure were studied by Differential Scanning Calorimetry and Positron Annihilation Lifetime Spectroscopy. Carbon dioxide, methane, nitrogen, oxygen and helium gas treatments as a function of pressure and duration at room temperature resulted in interesting changs in physical properties. An increase in specific heat below Tg and a decrease in Cp a this temperature will be discussed assuming changes in sub-nanometer structures in glassy Polysulfones, stable below Tg. The hole size and fraction increase and the free-volume distribution broadens with the pressure in the polysulfone-carbon dioxide system.

Jean, Y. C.; Yuan, J. P.; Hellmuth, E. W.

2001-03-01

213

DSC investigation of the effect of the new sigma ligand PPCC on DMPC lipid membrane.  

PubMed

The new sigma ligand cis-(±)-methyl (1R,2S/1S,2R)-2-[(4-hydroxy-4-phenylpiperidin-1-yl) methyl]-1-(4-methylphenyl) cyclopropanecarboxylate [(±)-PPCC] is a promising tool for the treatment of various diseases. With the aim to investigate the absorption of (±)-PPCC by the cell membranes, in this study we evaluated the influence on thermotropic behavior of membrane model exerted by PPCC both as free base or as oxalic salt. To fulfill this purpose differential scanning calorimetry was used. The findings highlight that PPCC affects the thermodynamic parameters of phospholipids in different manner depending on whether it is in the salt or base form as well as function of the amount of drugs dispersed in the lipid matrix. The salt form of PPCC was uptaken by the membrane model faster than the free base. In addition, preliminary information on the use of a lipophilic carrier for PPCC was obtained. PMID:24768402

Sarpietro, Maria Grazia; Accolla, Maria Lorena; Cova, Annamaria; Prezzavento, Orazio; Castelli, Francesco; Ronsisvalle, Simone

2014-07-20

214

Correlation of the penetration enhancement with the influence of an alcohol/tocopheryl polyethylene glycol succinate (TPGS) cosolvent system on the molecular structure of the stratum corneum of nude mouse skin as examined by microscopic FTIR/DSC  

NASA Astrophysics Data System (ADS)

Tocopheryl polyethylene glycol succinate (TPGS) is a water-soluble derivative of natural source of vitamin E, which possesses a dual nature of lipophilicity and hydrophilicity, similar to a surface-active agent. The penetration enhancement of estradiol by an ethanol and TPGS cosolvent system (EtOH/TPGS) has been confirmed. In this study, the correlation of the penetration enhancement with the influence of the EtOH/TPGS cosolvent system on biophysical changes of the stratum corneum (SC) as examined by Fourier transformation infrared spectrometry differential scanning calorimetry (FTIR/DSC) was investigated. Thermotropic changes in the asymmetrical and symmetrical C-H stretching of hydrocarbon chains of lipids, and amide I and II bands that characterize the protein structure of the SC treated with different concentrations of the EtOH/TPGS cosolvent were examined in this investigation. Results demonstrated that a strong correlation of the influence on biophysical changes of the SC treated with the EtOH/TPGS cosolvent system with the penetration enhancement of estradiol by the corresponding cosolvent system was not evident. It was concluded that the incorporation of TPGS in the cosolvent system seemed only to have insignificantly modified the structural features of the SC. It was not obvious that the penetrant had encountered these modifications resulting in an improvement in the penetration of estradiol by TPGS.

Liou, Yi-Bo; Ho, Hsiu-O.; Chen, Shin-Yi; Sheu, Ming-Thau

2009-10-01

215

A Shortened Norwegian Adaptation of the Lie Scale for Children (LSC) and the Defensiveness Scale for Children (DSC)  

ERIC Educational Resources Information Center

Ten items consisting of five DSC items and five LSC items were translated into Norwegian in order (a) to control the verbal anxiety responses from defensive tendencies, (b) to handle the problem of response set (the tendency to answer a questionnaire in a stereotyped way), and (c) to permit research concerning the nature of defensiveness itself.…

Haugen, Richard

1978-01-01

216

Operation Manual for the TA Instruments DSC Q-100 and Q-20: Temperature Range: -90C 400C  

E-print Network

Operation Manual for the TA Instruments DSC Q-100 and Q-20: Temperature Range: -90°C ­ 400°C Sample of the pan and sample and crimp the pan according to instructions from your training. After crimping) if you do not change the sample name with each new sample. Click on the PROCEDURE tab to write your

Alpay, S. Pamir

217

An Investigation of Thermal Characteristic of Mechanical Crimp Textured Polyester Yarn by Differential Scanning Calorimeter (DSC)  

NASA Astrophysics Data System (ADS)

Deficiencies related to the lack of bulk in flat continuous filament yarns make them unsuitable for apparel, home textiles as well as other applications such as car seat covering. Hence, texturising is employed to impart lofty and bulky characteristics to them. The two major texturising techniques employed for polyester yarn are false-twist and air-jet texturising. Out of these earlier technique depends on the thermoplasticity of the yarn being textured whereas the later one demands subsequent amount of compressed air to carry out cold fluid texturising. A new concept of mechanical crimp texturising has been designed to overcome these limitations of commercially successful techniques. In this new technique, pre-twisted FDY (Fully Drawn Yarn) flat multifilament yarn has been subjected to the higher false-twisting (depending on yarn fineness) action under the condition of underfeed (depending on ductility of parent yarn). The torque caused due to high level of false-twisting, forces the filaments to follow helical path at a certain angle (depends on magnitude of twist and denier per filament) to the filament yarn longitudinal axis. Internal stresses arising in single filaments tend to bend the filament and take the shape of spatial helical spring. After the yarn has passed through the false twisting unit, the initial twist would reassert itself and lock the already formed crimpy convolutions in position. Mechanical crimp textured polyester yarns with different pre-twist and false-twist levels have been subjected to thermal stress analysis using differential Scanning Calorimeter (DSC) in heat-cool-heat mode. The samples were heated at a rate of 10°C/minute. Almost all samples appear to be crystalline in nature. However, the melting endotherm does not show sharp peak. Instead, the diffuse nature of the peak is a signature of a partial crystalline nature (48%) of the samples. After melting the specimens, cooling of the same leads to crystallization of the material. This is exhibited by the exotherm. Heating the so-cooled samples, in general, increases their melting point in almost all samples. Thus melting event is shifted towards higher temperature, except for one sample in which pre-twist level is appreciably high. Thus, DSC is a very useful technique to select and optimize the pre-twist level and may provide quite a significant insight into the thermal stability of the mechanical crimp textured yarn.

Bhattacharya, Someshwar S.; Shaikh, Tasnim N.; Pratap, Arun

2010-06-01

218

DSC study of the isothermal crystallization of iPP-CNF nanocomposites  

NASA Astrophysics Data System (ADS)

Nanocomposite materials have been obtained by dispersing vapor grown carbon nanofibers (VGCNFs) with diameters ranging between 60 and 100 nm and lengths between 30,000 and 100,000 nm supplied by Pyrograf Products, Inc (PR-24AG) within a polymer matrix - isotactic polypropylene (iPP) - type Marlex HLN-120-01 with density 0.906 g/cm^3 and melt flow rate at 230 ^oC of 12 g/10 min, supplied by Philips Sumika Polypropylene Company. VGCNFs have been purified and disentangled by reflux in dichloromethane and deionized water followed by vacuum filtering (for 24 h) and drying at 110 ^oC for 24h. The nanocomposites were obtained by melt mixing at 180 ^oC for 9 minutes with a speed of 65 rpm followed by an additional mixing at 90 rpm for 5 minutes, using a HAAKE Rheomix, Nanocomposites loaded with various amounts of VGCNFs (0%, 1%, 2.5%, 5%, 7.5%, 10%, 15%, and 20% wt.) have been prepared and investigated by TA DSC Q-500. Isothermal crystallization was investigated in detail and analyzed by using an expression derived from the Avrami equation. The effect of the filler on the isothermal crystallization of iPP is discussed in detail. The research is focused on the effect of VGCNF on the degree of crystallization of iPP, crystallization rate, and dimensionality of the crystallization process.

Chipara, Dorina M.; Chipara, Mircea

2013-03-01

219

Reliable estimation of capillary transit time distributions using DSC-MRI.  

PubMed

The regional availability of oxygen in brain tissue is traditionally inferred from the magnitude of cerebral blood flow (CBF) and the concentration of oxygen in arterial blood. Measurements of CBF are therefore widely used in the localization of neuronal response to stimulation and in the evaluation of patients suspected of acute ischemic stroke or flow-limiting carotid stenosis. It was recently demonstrated that capillary transit time heterogeneity (CTH) limits maximum oxygen extraction fraction (OEF(max)) that can be achieved for a given CBF. Here we present a statistical approach for determining CTH, mean transit time (MTT), and CBF using dynamic susceptibility contrast magnetic resonance imaging (DSC-MRI). Using numerical simulations, we demonstrate that CTH, MTT, and OEF(max) can be estimated with low bias and variance across a wide range of microvascular flow patterns, even at modest signal-to-noise ratios. Mean transit time estimated by singular value decomposition (SVD) deconvolution, however, is confounded by CTH. The proposed technique readily identifies malperfused tissue in acute stroke patients and appears to highlight information not detected by the standard SVD technique. We speculate that this technique permits the non-invasive detection of tissue with impaired oxygen delivery in neurologic disorders such as acute ischemic stroke and Alzheimer's disease during routine diagnostic imaging. PMID:24938401

Mouridsen, Kim; Hansen, Mikkel Bo; Østergaard, Leif; Jespersen, Sune Nørhøj

2014-09-01

220

Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC  

SciTech Connect

Complex heat capacity, C{sub p}* = C{sub p}' - iC{sub p}'', of lithium borate glasses Li2O{center_dot}(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent C{sub p}* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena.

Matsuda, Yu; Ike, Yuji [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571 (Japan); Matsui, Chihiro [College of Engineering Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan); Kodama, Masao [Department of Applied Chemistry, Sojo University, Kumamoto, 860-0082 (Japan); Kojima, Seiji [Graduate School of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8571 (Japan); College of Engineering Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)

2006-05-05

221

Determination of the Heat of Combustion of Biodiesel Using Bomb Calorimetry: A Multidisciplinary Undergraduate Chemistry Experiment  

ERIC Educational Resources Information Center

Biodiesel was synthesized by transesterification of waste vegetable oil using common glassware and reagents, and characterized by measuring heat of combustion, cloud point, density and measuring the heat of combustion and density together allows the student the energy density of the fuel. Analyzing the biodiesel can serve as a challenging and…

Akers, Stephen M.; Conkle, Jeremy L.; Thomas, Stephanie N.; Rider, Keith B.

2006-01-01

222

Criteria for Downhill Protein Folding: Calorimetry, Chevron Plot, Kinetic Relaxation, and Single-Molecule  

E-print Network

chevron rollovers, the relaxation of the models considered is essen- tially single-exponential overCriteria for Downhill Protein Folding: Calorimetry, Chevron Plot, Kinetic Relaxation, and Single-Molecule Radius of Gyration in Chain Models With Subdued Degrees of Cooperativity Michael Knott and Hue Sun Chan

Chan, Hue Sun

223

Applications of conduction calorimetry to the setting reaction of zinc phosphate dental cement  

Microsoft Academic Search

The kinetics of the exothermic setting reaction of zinc phosphate dental cement can be successfully investigated by conduction calorimetry. The primary objective of this study is to examine the effects arising from the addition of various additives to the liquid and calcination of cement powder. The rate of heat evolution versus time shows the occurrence of merely one maximum. In

O. Pawlig; R. Trettin

1999-01-01

224

Determination of caloric values of agricultural crops and crop waste by Adiabatic Bomb Calorimetry  

Technology Transfer Automated Retrieval System (TEKTRAN)

Calorific values of agricultural crops and their waste were measured by adiabatic bomb calorimetry. Sustainable farming techniques require that all potential sources of revenue be utilized. A wide variety of biomass is beginning to be used as alternative fuels all over the world. The energy potentia...

225

Accelerating rate calorimetry: A new technique for safety studies in lithium systems  

NASA Technical Reports Server (NTRS)

The role of exothermic reactions in battery test modes is discussed. The exothermic reactions are characterized with respect to their time-temperature and time-pressure behavior. Reactions occuring for any major exotherm were examined. The accelerating rate calorimetry methods was developed to study lithium cells susceptibility to thermal runaway reactions following certain abuse modes such as forced discharge into reversal and charging.

Ebner, W. B.

1982-01-01

226

Differential scanning calorimetry study of the reactivity of carbon anodes in plastic Li-ion batteries  

Microsoft Academic Search

Chemical reactions taking place at elevated temperatures in a polymer-bonded lithiated carbon anode were studied by differential scanning calorimetry. The influences of parameters such as degree of intercalation, number of cycles, specific surface area, and chemical nature of the binder were elucidated. It was clearly established that the first reaction taking place at ca. 120--140 C was the transformation of

A. du Pasquier; F. Disma; J. M. Tarascon; T. Bowmer; A. S. Gozdz; G. Amatucci

1998-01-01

227

Thermal diffusivity measurements in organic liquids using transient thermal lens calorimetry  

E-print Network

Thermal diffusivity measurements in organic liquids using transient thermal lens calorimetry C. V. Thermal diffusivity measurements are carried out in certain organic liquids using the pulsed dual beam and it is closely related to thermal conductivity, specific heat and thermal expansion. An ex- tensive review

Harilal, S. S.

228

LuAG:Ce fibers for high energy calorimetry  

SciTech Connect

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.

Dujardin, C.; Mancini, C.; Amans, D.; Ledoux, G. [Universite Lyon 1, CNRS, UMR5620, Laboratoire de Physico-Chimie des Materiaux Luminescents, Universite de Lyon, F-69622 Villeurbanne Cedex (France); Abler, D.; Auffray, E.; Lecoq, P. [CERN, 1211 Geneva 23 (Switzerland); Perrodin, D. [Fibercryst, La Doua, Bat. Atrium, Bd Latarjet, F- 69616 Villeurbanne (France); Petrosyan, A.; Ovanesyan, K. L. [Laboratory of Crystal Growth of Luminescent Materials, Institute for Physical Research, Armenian National Academy of Science, 0203 Ashtarak-2 (Armenia)

2010-07-15

229

A theoretical framework to model DSC-MRI data acquired in the presence of contrast agent extravasation  

NASA Astrophysics Data System (ADS)

Dynamic susceptibility contrast (DSC) MRI methods rely on compartmentalization of the contrast agent such that a susceptibility gradient can be induced between the contrast-containing compartment and adjacent spaces, such as between intravascular and extravascular spaces. When there is a disruption of the blood-brain barrier, as is frequently the case with brain tumors, a contrast agent leaks out of the vasculature, resulting in additional T1, T2 and T*2 relaxation effects in the extravascular space, thereby affecting the signal intensity time course and reducing the reliability of the computed hemodynamic parameters. In this study, a theoretical model describing these dynamic intra- and extravascular T1, T2 and T*2 relaxation interactions is proposed. The applicability of using the proposed model to investigate the influence of relevant MRI pulse sequences (e.g. echo time, flip angle), and physical (e.g. susceptibility calibration factors, pre-contrast relaxation rates) and physiological parameters (e.g. permeability, blood flow, compartmental volume fractions) on DSC-MRI signal time curves is demonstrated. Such a model could yield important insights into the biophysical basis of contrast-agent-extravasastion-induced effects on measured DSC-MRI signals and provide a means to investigate pulse sequence optimization and appropriate data analysis methods for the extraction of physiologically relevant imaging metrics.

Quarles, C. C.; Gochberg, D. F.; Gore, J. C.; Yankeelov, T. E.

2009-10-01

230

Experimental measurements of the heats of formation of Fe{sub 3}Pt, FePt, and FePt{sub 3} using differential scanning calorimetry  

SciTech Connect

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.

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

231

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

NASA Astrophysics Data System (ADS)

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 presentations, now reported in these proceedings, that were debated in stimulating and fruitful discussions. Outside of the Workshop, the participants were able to visit the historical Halls and Museum of the University, whose foundation dates back to the year 1361, and to enjoy a visit to the Certosa, a Carthusian monastery renowned for its exuberant architecture. Pavia welcomed the Conference participants by opening the doors of the Town Hall and offering a reception during which the Mayor's address underlined the importance of research and its applications in modern society. The successful organization and the smooth running of the Conference is due to many people and Institutions. We gratefully acknowledge the financial support of the Istituto Nazionale di Fisica Nucleare (INFN), the Department of Nuclear and Theoretical Physics and the University of Pavia, that made the Workshop possible, together with the contribution of our sponsors. The University also opened some rooms of the Chancellor's suite for the lunch and coffee breaks, and hosted the Conference Secretariat. We would like to express our deepest gratitude to the INFN and Department technical staff, who helped to prepare the Hall for the Conference and to provide computer services, and to the staff of the Theresian Library, who gave us access to the Room and organized a display of the many historical books from their vast and precious collections which are of interest to physicists. Above all, the success of the meeting is due to the participants who animated it, and in particular to the speakers for their dedicated work in preparing their excellent talks and in providing the write-ups, and to the conveners for their essential role in shaping an interesting and well balanced scientific program. Finally, we wish to thank the International Advisory Committee for their unfailing support and for offering us the opportunity to organize this Conference in Pavia. Michele Livan Chairman, Organizing Committee International Advisory Commitee M Danilov, ITEP Moscow M Diemoz, INFN Roma I A Ereditato, Bern F Fabbri, I

Livan, Michele

2009-07-01

232

Temperature dependence of adsorption of PEGylated lysozyme and pure polyethylene glycol on a hydrophobic resin: comparison of isothermal titration calorimetry and van't Hoff data.  

PubMed

The influence of temperature on the adsorption of PEGylated lysozyme and pure PEG on Toyopearl PPG-600M, a hydrophobic resin, is studied by batch equilibrium measurements and pulse response experiments. Differently PEGylated lysozymes are used for the studies, enabling a systematic variation of the solute properties. Either ammonium sulfate or sodium chloride are added. The enthalpy of adsorption is calculated from a van't Hoff analysis based on these data. It is also directly measured by Isothermal Titration Calorimetry. In the investigated temperature range from 5 °C to 35 °C adsorption is favored by higher temperatures and hence endothermic. The results of the van't Hoff analysis of the equilibrium and the pulse response data agree well. Discrepancies between enthalpies of adsorption obtained by calorimetry and van't Hoff analysis are found and discussed. We conclude that the most likely explanation is that thermodynamic equilibrium is not reached in the experiments even though they were carried out carefully and in the generally accepted way. PMID:25016322

Werner, Albert; Hackemann, Eva; Hasse, Hans

2014-08-22

233

Use of DSC and DMA Techniques to Help Investigate a Material Anomaly for PTFE Used in Processing a Piston Cup for the Urine Processor Assembly (UPA) on International Space Station (ISS)  

NASA Technical Reports Server (NTRS)

Human urine and flush water are eventually converted into drinking water with the Urine Processor Assembly (UPA) aboard the International Space Station (ISS). This conversion is made possible through the Distillation Assembly (DA) of the UPA. One component of the DA is a molded circular piston cup made of virgin polytetrafluoroethylene (PTFE). The piston cup is assembled to a titanium component using eight fasteners and washers. Molded PTFE produced for spare piston cups in the first quarter of 2010 was different in appearance and texture, and softer than material molded for previous cups. For the suspect newer PTFE material, cup fasteners were tightened to only one-half the required torque value, yet the washers embedded almost halfway into the material. The molded PTFE used in the DA piston cup should be Type II, based on AMS 3667D and ASTM D4894 specifications. The properties of molded PTFE are considerably different between Type I and II materials. Engineers working with the DA thought that if Type I PTFE was molded by mistake instead of Type II material, that could have resulted in the anomalous material properties. Typically, the vendor molds flat sheet PTFE from the same material lot used to mold the piston cups, and tensile testing as part of quality control should verify that the PTFE is Type II material. However, for this discrepant lot of material, such tensile data was not available. Differential scanning calorimetry (DSC) and dynamic mechanical analysis (DMA) were two of the testing techniques used at the NASA/Marshall Space Flight Center (MSFC) to investigate the anomaly for the PTFE material. Other techniques used on PTFE specimens were: Shore D hardness testing, tensile testing on dog bone specimens and a qualitative estimation of porosity by optical and scanning electron microscopy.

Wingard, Doug

2010-01-01

234

Radiation damage study for silicon calorimetry: Summary of first year's activity  

SciTech Connect

In the first contract year of this activity at Carnegie-Mellon we have had two major objectives. These were to devise and test a non-intrusive means to measure the energy and spatial profiles of the neutrons generated in a hadronic cascade at high energy; and to study the calibration systematics of silicon diode detectors as a prelude to their evaluation for SSC calorimetry. These objectives have been carried out, as are described in this paper. In addition we have recoded the ORNL detector simulation program HETC to operate on a VAX and are working on the conversion of the low energy neutron transport program MORSE. These programs are used heavily at Oak Ridge (Gabriel and coworkers) for cascade studies. For silicon calorimetry one wants to have more control over the energy deposition routines, especially in MORSE. Unfortunately, MORSE is heavily-laden with machine code, and its conversion is going slowly. 11 refs., 5 figs.

Russ, J.S.

1988-01-01

235

Determination of the catalytic activity of binuclear metallohydrolases using isothermal titration calorimetry.  

PubMed

Binuclear metallohydrolases are a large and diverse family of enzymes that are involved in numerous metabolic functions. An increasing number of members find applications as drug targets or in processes such as bioremediation. It is thus essential to have an assay available that allows the rapid and reliable determination of relevant catalytic parameters (k cat, K m, and k cat/K m). Continuous spectroscopic assays are frequently only possible by using synthetic (i.e., nonbiological) substrates that possess a suitable chromophoric marker (e.g., nitrophenol). Isothermal titration calorimetry, in contrast, affords a rapid assay independent of the chromophoric properties of the substrate-the heat associated with the hydrolytic reaction can be directly related to catalytic properties. Here, we demonstrate the efficiency of the method on several selected examples of this family of enzymes and show that, in general, the catalytic parameters obtained by isothermal titration calorimetry are in good agreement with those obtained from spectroscopic assays. PMID:24414447

Pedroso, Marcelo M; Ely, Fernanda; Lonhienne, Thierry; Gahan, Lawrence R; Ollis, David L; Guddat, Luke W; Schenk, Gerhard

2014-03-01

236

Thermal characterization of starch-water system by photopyroelectric technique and adiabatic scanning calorimetry  

NASA Astrophysics Data System (ADS)

Starch is one of the most important carbohydrate sources in human nutrition. For the thermal analysis of starch, techniques such as differential scanning calorimetry have been extensively used. As an alternative, we have applied a photopyroelectric (PPE) configuration and adiabatic scanning calorimetry (ASC) to study the thermal properties of starch-water systems. For this study we used nixtamalized corn flour and potato starch with different quantities of distilled water, in order to obtain samples with different moisture content. By using PPE and ASC methods we have measured, for each technique separately, the heat capacity by unit volume (?cp) at room temperature for a corn flour sample at 90% moisture. The obtained values agree within experimental uncertainty. By using these techniques we also studied the thermal behavior of potato starch, at 80% moisture, in the temperature range where phase transitions occur. In this case the PPE signal phase could be used as a sensitive and versatile monitor for phase transitions.

Cruz-Orea, A.; Bentefour, E. H.; Jamée, P.; Chirtoc, M.; Glorieux, C.; Pitsi, G.; Thoen, J.

2003-01-01

237

Hydration-dehydration of human serum albumin studied by isothermal calorimetry and IR spectroscopy  

Microsoft Academic Search

Based on a comparison of the data on the isothermal calorimetry of the interaction of human serum albumin with water and the\\u000a adsorption isotherms of water vapor on the protein obtained by IR spectroscopy, an experimental method was used for the first\\u000a time to study the thermochemical and sorption characteristics of protein hydration-dehydration over the entire range of the\\u000a thermodynamic

V. A. Sirotkin; D. V. Korolev; A. E. Silakova

2007-01-01

238

31P NMR and isothermal titration calorimetry studies on polyoxomolybdates-catalyzed hydrolysis of ATP  

Microsoft Academic Search

ATP hydrolysis in the presence of polyoxomolybdates at pH levels of 6, 4, and 2 has been investigated with a help of high pressure liquid chromatography (HPLC) analyses, 31P- and 1H NMR measurements, and isothermal titration calorimetry (ITC). The polyoxomolybdates-induced ATP-hydrolysis proceeded satisfactorily in pH<6 media at 20°C with an optimum pH level of 4, while it was significantly depressed

Eri Ishikawa; Toshihiro Yamase

2006-01-01

239

Molecular Characterization and Alternative Splicing of a Sodium Channel and DSC1 Ortholog Genes in Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae)  

PubMed Central

Alternative splicing greatly contributes to the structural and functional diversity of voltage-gated sodium channels (VGSCs) by generating various isoforms with unique functional and pharmacological properties. Here, we identified a new optional exon 23 located in the linker between domains II and III, and four mutually exclusive exons (exons 27A, 27B, 27C, and 27D) in domains IIIS3 and IIIS4 of the sodium channel of Liposcelis bostrychophila (termed as LbVGSC). This suggested that more alternative splicing phenomena remained to be discovered in VGSCs. Inclusion of exon 27C might lead to generation of non-functional isoforms. Meanwhile, identification of three alternative exons (exons 11, 13A, and 13B), which were located in the linker between domains II and III, indicated that abundant splicing events occurred in the DSC1 ortholog channel of L. bostrychophila (termed as LbSC1). Exons 13A and 13B were generated by intron retention, and the presence of exon 13B relied on the inclusion of exon 13A. Exon 13B was specifically expressed in the embryonic stage and contained an in-frame stop codon, inclusion of which led to generation of truncated proteins with only the first two domains. Additionally, several co-occurring RNA editing events were identified in LbSC1. Furthermore, remarkable similarity between the structure and expression patterns of LbVGSC and LbSC1 were discovered, and a closer evolutionary relationship between VGSCs and DSC1 orthologs was verified. Taken together, the data provided abundant molecular information on VGSC and DSC1 orthologs in L. bostrychophila, a representative Psocoptera storage pest, and insights into the alternative splicing of these two channels. PMID:24155671

Jiang, Xuan-Zhao; Wei, Dan-Dan; Yang, Wen-Jia; Dou, Wei; Chen, Shi-Chun; Wang, Jin-Jun

2013-01-01

240

Molecular characterization and alternative splicing of a sodium channel and DSC1 ortholog genes in Liposcelis bostrychophila Badonnel (Psocoptera: Liposcelididae).  

PubMed

Alternative splicing greatly contributes to the structural and functional diversity of voltage-gated sodium channels (VGSCs) by generating various isoforms with unique functional and pharmacological properties. Here, we identified a new optional exon 23 located in the linker between domains II and III, and four mutually exclusive exons (exons 27A, 27B, 27C, and 27D) in domains IIIS3 and IIIS4 of the sodium channel of Liposcelis bostrychophila (termed as LbVGSC). This suggested that more alternative splicing phenomena remained to be discovered in VGSCs. Inclusion of exon 27C might lead to generation of non-functional isoforms. Meanwhile, identification of three alternative exons (exons 11, 13A, and 13B), which were located in the linker between domains II and III, indicated that abundant splicing events occurred in the DSC1 ortholog channel of L. bostrychophila (termed as LbSC1). Exons 13A and 13B were generated by intron retention, and the presence of exon 13B relied on the inclusion of exon 13A. Exon 13B was specifically expressed in the embryonic stage and contained an in-frame stop codon, inclusion of which led to generation of truncated proteins with only the first two domains. Additionally, several co-occurring RNA editing events were identified in LbSC1. Furthermore, remarkable similarity between the structure and expression patterns of LbVGSC and LbSC1 were discovered, and a closer evolutionary relationship between VGSCs and DSC1 orthologs was verified. Taken together, the data provided abundant molecular information on VGSC and DSC1 orthologs in L. bostrychophila, a representative Psocoptera storage pest, and insights into the alternative splicing of these two channels. PMID:24155671

Jiang, Xuan-Zhao; Wei, Dan-Dan; Yang, Wen-Jia; Dou, Wei; Chen, Shi-Chun; Wang, Jin-Jun

2013-01-01

241

Reading and Listening to Music Increase Resting Energy Expenditure during an Indirect Calorimetry Test.  

PubMed

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 (P<0.0001); however, there was no difference in REE between the electronic device and magazine. Listening to self-selected relaxing music 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. PMID:24794837

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

2014-12-01

242

Diclofenac Salts. V. Examples of Polymorphism among Diclofenac Salts with Alkyl-hydroxy Amines Studied by DSC and HSM  

PubMed Central

Nine diclofenac salts prepared with alkyl-hydroxy amines were analyzed for their properties to form polymorphs by DSC and HSM techniques. Thermograms of the forms prepared from water or acetone are different in most cases, suggesting frequent examples of polymorphism among these salts. Polymorph transition can be better highlighted when analysis is carried out by thermo-microscopy, which in most cases made it possible to observe the processes of melting of the metastable form and re-crystallization of the stable one. Solubility values were qualitatively related to the crystal structure of the salts and the molecular structure of the cation.

Fini, Adamo; Cavallari, Cristina; Ospitali, Francesca

2010-01-01

243

HEAT OF HYDRATION OF SALTSTONE MIXES-MEASUREMENT BY ISOTHERMAL CALORIMETRY  

SciTech Connect

This report provides initial results on the measurement of heat of hydration of Saltstone mixes using isothermal calorimetry. The results were obtained using a recently purchased TAM Air Model 3116 Isothermal Conduction Calorimeter. Heat of hydration is an important property of Saltstone mixes. Greater amounts of heat will increase the temperature of the curing mix in the vaults and limit the processing rate. The heat of hydration also reflects the extent of the hydraulic reactions that turn the fluid mixture into a ''stone like'' solid and consequently impacts performance properties such as permeability. Determining which factors control these reactions, as monitored by the heat of hydration, is an important goal of the variability study. Experiments with mixes of portland cement in water demonstrated that the heats measured by this technique over a seven day period match very well with the literature values of (1) seven day heats of hydration using the standard test method for heat of hydration of hydraulic cement, ASTM C 186-05 and (2) heats of hydration measured using isothermal calorimetry. The heats of hydration of portland cement or blast furnace slag in a Modular Caustic Side Solvent Extraction Unit (MCU) simulant revealed that if the cure temperature is maintained at 25 C, the amount of heat released over a seven day period is roughly 62% less than the heat released by portland cement in water. Furthermore, both the blast furnace slag and the portland cement were found to be equivalent in heat production over the seven day period in MCU. This equivalency is due to the activation of the slag by the greater than 1 Molar free hydroxide ion concentration in the simulant. Results using premix (a blend of 10% cement, 45% blast furnace slag, and 45% fly ash) in MCU, Deliquification, Dissolution and Adjustment (DDA) and Salt Waste Processing Facility (SWPF) simulants reveal that the fly ash had not significantly reacted (undergone hydration reactions) after seven days (most likely less than 5%). There were clear differences in the amount of heat released and the peak times of heat release for the three different simulants. It turns out that SWPF simulant mixes give off greater heat than does MCU and DDA simulant mixes. The temperature dependence of the heat of hydration was measured by carrying out these measurements at 25, 40 and 55 C. In general, the peak times shifted to shorter times as the isothermal temperature increased and the amount of heat released was independent of temperature for DDA and MCU but slightly higher at higher temperatures for SWPF. The goal of this study is to apply this technique to the measurement of the heat of hydration of mixes that will be made as part of the variability study. It is important to understand which variables will impact (and to what extent) the amount of heat generated and the peak times for the heat release. Those variables that can be controlled can then be tuned to adjust the heat of hydration as long as the other properties are still acceptable. The first application of heat of hydration measurements to the variability study was completed and the results presented in this report. These measurements were made using Phase VI mixes (SWPF simulants) following a statistical design that included variation in the compositional and operational variables. Variation in both the amount of heat released and the peak times for the heat release were observed. The measured ranges were 23 Joules per gram of premix for the heat release and 23 hours for the peak time of heat release at 25 C. Linear models with high R{sup 2} values and no statistical evidence for lack of fit were developed that relate the amount of heat release and the peak time for heat release for the Phase VI mixes to certain variables. The amount of heat released was a function of the aluminate and portland cement concentrations as well as the temperature of mixing. The peak time for heat release was a function of aluminate, portland cement and total nitrate plus nitrite concentrations. A comparison was made of the mea

Harbour, J; Vickie Williams, V; Tommy Edwards, T

2007-07-02

244

An Efficient Computational Approach to Characterize DSC-MRI Signals Arising from Three-Dimensional Heterogeneous Tissue Structures  

PubMed Central

The systematic investigation of susceptibility-induced contrast in MRI is important to better interpret the influence of microvascular and microcellular morphology on DSC-MRI derived perfusion data. Recently, a novel computational approach called the Finite Perturber Method (FPM), which enables the study of susceptibility-induced contrast in MRI arising from arbitrary microvascular morphologies in 3D has been developed. However, the FPM has lower efficiency in simulating water diffusion especially for complex tissues. In this work, an improved computational approach that combines the FPM with a matrix-based finite difference method (FDM), which we call the Finite Perturber the Finite Difference Method (FPFDM), has been developed in order to efficiently investigate the influence of vascular and extravascular morphological features on susceptibility-induced transverse relaxation. The current work provides a framework for better interpreting how DSC-MRI data depend on various phenomena, including contrast agent leakage in cancerous tissues and water diffusion rates. In addition, we illustrate using simulated and micro-CT extracted tissue structures the improved FPFDM along with its potential applications and limitations. PMID:24416281

Semmineh, Natenael B.; Xu, Junzhong; Boxerman, Jerrold L.; Delaney, Gary W.; Cleary, Paul W.; Gore, John C.; Quarles, C. Chad

2014-01-01

245

Studies on the formability of Al-based metallic glasses\\/nanocomposites based on isochronal DSC analysis  

Microsoft Academic Search

The Al86Si0.5Ni4.06Co2.94Y6Sc0.5 metallic glass of highly improved glass-forming ability (GFA) has been investigated by isochronal differential scanning calorimetry measurements, as well as the Al85Ni5Co2Y8 for comparison. The experimental results indicate that the Al86Si0.5Ni4.06Co2.94Y6Sc0.5 exhibits enlarged temperature interval between the first and second crystallization onsets (termed as primary fcc-Al\\/glass region), as well as enlarged second activation energy (Ep2) against the nucleation

Longchao Zhuo; Tao Zhang

2010-01-01

246

Transformations in Fe-20 wt pct Cr Alloy: Drop Calorimetry Study and Elucidation of Magnetic Contribution to Phase Stability  

NASA Astrophysics Data System (ADS)

There is considerable uncertainty among diverse assessments of phase equilibrium in Fe-Cr alloys, especially around ( ?' + ??)/ ? miscibility gap region. This is largely due to the difficulty associated with the rigorous incorporation of the interplay between magnetic and chemical contribution to phase stability, in particular its composition and temperature dependencies through theory, in the absence of reliable experimental data. Toward this cause, accurate enthalpy measurements have been made on homogenized Fe-20 wt pct Cr alloy using inverse drop calorimetry, in the temperature range 298 K to 1473 K (25 °C to 1200 °C). The experiments revealed two distinct phase transformations: (i) at 720 ± 10 K (447 ± 10 °C), the Fe-20Cr alloy transformed from ?'(Fe-rich) + ??(Cr-rich) two-phase microstructure to ? single phase and (ii) at 925 ± 10 K (652 ± 10 °C), the ferromagnetic single-phase ? transformed to paramagnetic state. Both these transformations are clearly attested by the measured enthalpy increment variation with temperature. The enthalpy data obtained in this study have been combined with available literature information to forge an integrated theoretical assessment of the energetic aspects of ?' + ?? ? ?, and ? ferro ? ? para transformations. In addition, a comprehensive evaluation of enthalpy and heat capacity data for Fe-20Cr alloy in the temperature range 0 K to 1473 K (-273 °C to 1200 °C), with explicit incorporation of magnetic contribution has also been made.

Hajra, Raj Narayan; Raju, Subramanian; Rai, Arun Kumar; Tripathy, Haraprasanna; Saibaba, Saroja

2014-07-01

247

X-linked dystonia parkinsonism syndrome (XDP, lubag): disease-specific sequence change DSC3 in TAF1/DYT3 affects genes in vesicular transport and dopamine metabolism.  

PubMed

X-chromosomal dystonia parkinsonism syndrome (XDP, 'lubag') is associated with sequence changes within the TAF1/DYT3 multiple transcript system. Although most sequence changes are intronic, one, disease-specific single-nucleotide change 3 (DSC3), is located within an exon (d4). Transcribed exon d4 occurs as part of multiple splice variants. These variants include exons d3 and d4 spliced to exons of TAF1, and an independent transcript composed of exons d2-d4. Location of DSC3 in exon d4 and utilization of this exon in multiple splice variants suggest an important role of DSC3 in the XDP pathogenesis. To test this hypothesis, we transfected neuroblastoma cells with four expression constructs, including exons d2-d4 [d2-d4/wild-type (wt) and d2-d4/DSC3] and d3-d4 (d3-d4/wt and d3-d4/DSC3). Expression profiling revealed a dramatic effect of DSC3 on overall gene expression. Three hundred and sixty-two genes differed between cells containing d2-d4/wt and d2-d4/DSC3. Annotation clustering revealed enrichment of genes related to vesicular transport, dopamine metabolism, synapse function, Ca(2+) metabolism and oxidative stress. Two hundred and eleven genes were differentially expressed in d3-d4/wt versus d3-d4/DSC3. Annotation clustering highlighted genes in signal transduction and cell-cell interaction. The data show an important role of physiologically occurring transcript d2-d4 in normal brain function. Interference with this role by DSC3 is a likely pathological mechanism in XDP. Disturbance of dopamine function and of Ca(2+) metabolism can explain abnormal movement; loss of protection against reactive oxygen species may account for the neurodegenerative changes in XDP. Although d3-d4 also affect genes potentially related to neurodegenerative processes, their physiologic role as splice variants of TAF1 awaits further exploration. PMID:23184149

Herzfeld, Thilo; Nolte, Dagmar; Grznarova, Maria; Hofmann, Andrea; Schultze, Joachim L; Müller, Ulrich

2013-03-01

248

Standard enthalpies of formation of some praseodymium alloys by high-temperature direct synthesis calorimetry  

Microsoft Academic Search

The standard enthalpies of formation of eight Pr alloys were determined by direct synthesis calorimetry at 1473 ? 2 K. The\\u000a following values of ?Hskƒ\\/?(kJ\\/g atom) are reported: PrNi5, ?(25.6 ? 1.0); PrRu2, ?(16.9 ? 1.5); PrRh2, ?(60.4 ? 1.7); PrPd, ?(78.8 ? 2.5); PrPd2, ?(82.7 ? 3.1); PrIr2, ?(70.7 ? 2.8); PrPt, ?(103.4 ? 2.7); and PrPt2, ? (93.5

Qiti Guo; O. J. Kleppa

1994-01-01

249

Azide derivatized anticancer agents of Vitamin K 3: X-ray structural, DSC, resonance spectral and API studies  

NASA Astrophysics Data System (ADS)

Compound 1 [1-imino (acetyl hydrazino)-Vitamin K 3], displays valence tautomerically related electronic isomers as Form I and Form II. Form I exhibits 2D packing fragment with 1D ribbon chains of N-H⋯O hydrogen bonds and shows EPR silent features. While Form II is EPR active and exhibits biradical nature with double quantum transitions at g = 2.0040. 1H NMR of compound 2, [1-imino (hydrazino carboxylate)-Vitamin K 3] and Form II exhibit ? delocalization via resonance assisted H-bonding [RAHB] effect compared to Form I. Molecular interactions in Form I and II are visualized by DSC. The electronic structures of compounds 1 and 2 have been correlated to their API values by measuring anticancer activities, mitochondrial potentials and DNA shearing patterns. Form II and compound 2 indicate mitochondria mediated apoptosis (˜75% cell death) while Form I causes 35% cell death.

Badave, Kirti; Patil, Yogesh; Gonnade, Rajesh; Srinivas, Darbha; Dasgupta, Rajan; Khan, Ayesha; Rane, Sandhya

2011-12-01

250

Kinetics of thermolysis of lanthanum nitrate with hexamethylenetetramine: Crystal structure, TG-DSC, impact and friction sensitivity studies, Part-96  

NASA Astrophysics Data System (ADS)

The development of high energetic materials includes process ability and the ability to attain insensitive munitions (IM). This paper investigates the preparation of lanthanum metal nitrate complex of hexamethylenetetramine in water at room temperature. This complex of molecular formulae [La (NO3)2(H2O)6] (2HMTA) (NO3-) (H2O) was characterized by X-ray crystallography. Thermal decomposition was investigated using TG, TG-DSC and ignition delay measurements. Kinetic analysis of isothermal TG data has been investigated using model fitting methods as well as model free isoconversional methods. The sensitivity measurements towards mechanical destructive stimuli such as impact and friction were carried out and the complex was found to be insensitive. In order to identify the end product of thermolysis, X-ray diffraction patterns of end product was carried out which proves the formation of La2O3.

Nibha; Baranwal, B. P.; Singh, Gurdip; Singh, C. P.; Daniliuc, Constantin G.; Soni, P. K.; Nath, Yogeshwar

2014-11-01

251

A DSC study on crystalline LaRC TPI powder - A new version with higher initial molecular weight  

NASA Technical Reports Server (NTRS)

A new version of crystalline Langley Research Center Thermoplastic Polyimide (LaRC-TPI) imidized powder, which possesses a higher initial molecular weight (MW), has been prepared and characterized. The scheme used for cyclodehydration during the synthesis of this material is described. Evidence of a higher initial MW for the subject LaRC-TPI is supported by both measurements of the inherent viscosity and the DSC thermograms. An initial melting peak at 295 C is noted in the freshly-synthesized sample. The powder can be recrystallized at any elevated temperatures below 340 C, and a single crystalline endothemic peak is always observed after various thermal histories. The heat of fusion for the fresh sample, as represented by the area under the melting peak in the directional scanning calorimeter thermogram, is about 3.9 cal/gm. Comparisons of thermal properties for the subject material are made to those exhibited by the commercial LaRC-TPI powder.

Hou, Tan-Hung; Bai, Jia-Mo; St. Clair, Terry L.

1987-01-01

252

Inclusion complexes of cypermethrin and permethrin with monochlorotriazinyl-beta-cyclodextrin: A combined spectroscopy, TG/DSC and DFT study  

NASA Astrophysics Data System (ADS)

The suitable size hydrophobic cavity and monochlorotriazinyl group as a reactive anchor make MCT-?-CD to be widely used in fabric finishing. In this paper, the inclusion complexes of monochlorotriazinyl-beta-cyclodextrin (MCT-?-CD) with cypermethrin (CYPERM) and permethrin (PERM) are synthesized and analyzed by TG/DSC, FT-IR and Raman spectroscopy. TG/DSC reveals that the decomposed temperatures of inclusion complexes are lower by 25-30 °C than that of physical mixtures. DFT calculations in conjunction with FT-IR and Raman spectral analyses are used to study the structures of MCT-?-CD and their inclusion complexes. Four isomers of trisubstituted MCT-?-CD are designed and DFT calculations reveal that 1,3,5-trisubstituted MCT-?-CD has the lowest energy and can be considered as main component of MCT-?-CD. The ground-state geometries, vibrational wavenumbers, IR and Raman intensities of MCT-?-CD and their inclusion complexes were calculated at B3LYP/6-31G (d) level of theory. Upon examining the optimized geometry of inclusion complex, we find that the CYPERM and PERM are inserted into the toroid of MCT-?-CD from the larger opening. The band at 1646 cm-1 in IR and at 1668 cm-1 in Raman spectrum reveals that monochloroazinyl group of MCT-?-CD exists in ketone form but not in anion form. The noticeable IR and Raman shift of phenyl reveals that these two benzene rings of CYPERM and PERM stays inside the cavity of MCT-?-CD and has weak interaction with MCT-?-CD. This spectroscopy conclusion is consistent with theoretical predicted structure.

Yao, Qi; You, Bin; Zhou, Shuli; Chen, Meng; Wang, Yujiao; Li, Wei

2014-01-01

253

Inclusion complexes of cypermethrin and permethrin with monochlorotriazinyl-beta-cyclodextrin: a combined spectroscopy, TG/DSC and DFT study.  

PubMed

The suitable size hydrophobic cavity and monochlorotriazinyl group as a reactive anchor make MCT-?-CD to be widely used in fabric finishing. In this paper, the inclusion complexes of monochlorotriazinyl-beta-cyclodextrin (MCT-?-CD) with cypermethrin (CYPERM) and permethrin (PERM) are synthesized and analyzed by TG/DSC, FT-IR and Raman spectroscopy. TG/DSC reveals that the decomposed temperatures of inclusion complexes are lower by 25-30 °C than that of physical mixtures. DFT calculations in conjunction with FT-IR and Raman spectral analyses are used to study the structures of MCT-?-CD and their inclusion complexes. Four isomers of trisubstituted MCT-?-CD are designed and DFT calculations reveal that 1,3,5-trisubstituted MCT-?-CD has the lowest energy and can be considered as main component of MCT-?-CD. The ground-state geometries, vibrational wavenumbers, IR and Raman intensities of MCT-?-CD and their inclusion complexes were calculated at B3LYP/6-31G (d) level of theory. Upon examining the optimized geometry of inclusion complex, we find that the CYPERM and PERM are inserted into the toroid of MCT-?-CD from the larger opening. The band at 1646 cm(-1) in IR and at 1668 cm(-1) in Raman spectrum reveals that monochloroazinyl group of MCT-?-CD exists in ketone form but not in anion form. The noticeable IR and Raman shift of phenyl reveals that these two benzene rings of CYPERM and PERM stays inside the cavity of MCT-?-CD and has weak interaction with MCT-?-CD. This spectroscopy conclusion is consistent with theoretical predicted structure. PMID:24103228

Yao, Qi; You, Bin; Zhou, Shuli; Chen, Meng; Wang, Yujiao; Li, Wei

2014-01-01

254

Characterization of polymer matrix and low melting point solder for anisotropic conductive film  

Microsoft Academic Search

The chemo-rheological mechanisms of a polymer matrix and a low melting point solder for an anisotropic conductive film (ACF) have been characterized. For the material characterization of the polymer matrix and solder, a differential scanning calorimetry (DSC) and a dynamic mechanical analyzer (DMA) experiments were conducted. The conversion and viscosity of the polymer matrix was observed by DSC and DMA,

Yong-Sung Eom; Ji-Won Baek; Jong-Tae Moon; Jae-Do Nam; Jong-Min Kim

2008-01-01

255

Psychometric evaluation of the Korean version of the Diabetes Symptom Checklist-Revised (DSC-R) for Patients with Type 2 Diabetes  

PubMed Central

Background This study was to elucidate the psychometric properties of the Korean version of the Diabetes Symptom Checklist-Revised (K-DSC-R), which is a patient-reported outcome measure of diabetes symptom burden. Methods A sample of 432 Korean patients with diabetes was recruited from university hospitals. The data were analyzed using exploratory factor analysis (EFA), confirmatory factor analysis (CFA), multitrait/multi-item correlation, Pearson’s correlation, t-test, ANOVA, and Cronbach’s alpha for construct, item-convergent/discriminant, concurrent, and known-groups validity, and internal consistency reliability. Results EFA extracted a total of 29 items clustered into 7 subscales from the K-DSC-R. The construct of the seven-subscales was supported by CFA. The scaling success rates of item-convergent validity were 100% for all subscales, and those of item-discriminant validity ranged from 83.3% to 100%. Patients in more-depressed groups and in the HbA1c-uncontrolled group had higher K-DSC-R scores, satisfying the known-groups validity. The subscales of the K-DSC-R were moderately correlated with health-related quality of life, indicative of the established concurrent validity. The Cronbach’s alpha of the K-DSC-R was 0.92. Conclusions The psychometric properties of the K-DSC-R have been established. It is thus appropriate for use with respect to reliability and validity in practice and clinical trials for Korean patients with type 2 diabetes. PMID:24885358

2014-01-01

256

Calorimetry, activity, and micro-FTIR analysis of CO chemisorption, titration, and oxidation on supported Pt  

NASA Technical Reports Server (NTRS)

The value of in situ analysis on CO chemisorption, titration and oxidation over supported Pt catalysts using calorimetry, catalytic and micro-FTIR methods is illustrated using silica- and titania-supported samples. Isothermal CO-O and O2-CO titrations have not been widely used on metal surfaces and may be complicated if some oxide supports are reduced by CO titrant. However, they can illuminate the kinetics of CO oxidation on metal/oxide catalysts since during such titrations all O and CO coverages are scanned as a function of time. There are clear advantages in following the rates of the catalyzed CO oxidation via calorimetry and gc-ms simultaneously. At lower temperatures the evidence they provide is complementary. CO oxidation and its catalysis of CO oxidation have been extensively studied with hysteresis and oscillations apparent, and the present results suggest the benefits of a combined approach. Silica support porosity may be important in defining activity-temperature hysteresis. FTIR microspectroscopy reveals the chemical heterogeneity of the catalytic surfaces used; it is interesting that the evidence with regard to the dominant CO surface species and their reactivities with regard to surface oxygen for present oxide-supported Pt are different from those seen on graphite-supported Pt.

Sermon, Paul A.; Self, Valerie A.; Vong, Mariana S. W.; Wurie, Alpha T.

1990-01-01

257

Integration of ultrafast scanning calorimetry with micro-Raman spectroscopy for investigation of metastable materials  

NASA Astrophysics Data System (ADS)

A stage-type ultrafast scanning calorimetry (ST-UFSC) with controlled heating and cooling rates up to 105 K s-1 was designed to integrate with microstructural characterization. This enables us to precisely control the evolution of fast transitional states of metastable samples provided by the UFSC platform, and to follow subtle structural changes between intermediate stages. As an example, we collected the Raman spectra of poly(ethylene terephthalate) quenched at different crystallization states obtained by programed rapid cooling and heating processes. Because of the very small sample mass for UFSC measurements, from minimum few nanograms to sub-micrograms, the sample's temperature is very sensitive to the perturbation from the laser illumination of the Raman spectrometer. Real time temperature monitoring and compensation was accompanied during the whole process of in situ spectroscopy. The results showed a good agreement of crystallization kinetics obtained from the Raman spectroscopy and from the calorimetric melting enthalpy, given that the sample temperature is well controlled during spectroscopic measurements and that the heating rate for calorimetry is fast enough to suppress structural reorganization during heating scans. We expect that the ST-UFSC is suitable to be integrated with other micro-analysis techniques to investigate the structure and dynamics of metastable states obtained by fast thermal treatments.

Wei, Lai; Jiang, Jing; Shan, Meijuan; Chen, Wei; Deng, Yu; Xue, Gi; Zhou, Dongshan

2014-07-01

258

Reference dosimetry for light-ion beams based on graphite calorimetry.  

PubMed

Developments in hadron therapy require efforts to improve the accuracy of the dose delivered to a target volume. Here, the determination of the absorbed dose under reference conditions was analysed. Based on the International Atomic Energy Agency TRS-398 code of practice, for hadron beams, the combined standard uncertainty on absorbed dose to water under reference conditions, derived from ionisation chambers, is too large. This uncertainty is dominated by the beam quality correction factors, [Formula: see text], mainly due to the mean energy to produce one ion pair in air, wair. A method to reduce this uncertainty is to carry out primary dosimetry, using calorimetry. A [Formula: see text]-value can be derived from a direct comparison between calorimetry and ionometry. Here, this comparison is performed using a graphite calorimeter in an 80-MeV A(-1) carbon ion beam. Assuming recommended TRS-398 values of water-to-graphite stopping power ratio and the perturbation factor for an ionisation chamber, preliminary results indicate a wair-value of 35.5 ± 0.9 J C(-1). PMID:24336190

Rossomme, S; Palmans, H; Thomas, R; Lee, N; Duane, S; Bailey, M; Shipley, D; Bertrand, D; Romano, F; Cirrone, P; Cuttone, G; Vynckier, S

2014-10-01

259

Measurement of thermal conductivity from high-temperature pulse diffusivity and calorimetry measurements  

SciTech Connect

The measurement of the thermal conductivity of small samples over an extended temperature range is discussed. Experimental data on thermal diffusivity obtained by the laser pulse technique are combined with specific heat data, obtained either by differential scanning calorimetry or by vaporization calorimetry, to derive the thermal conductivity. As an example of the use of this technique, data are reported on the conductivity of an ASTM A517 steel over the temperature range 100 to 1200/sup 0/C. The thermal diffusivity was derived from measured temperature vs time data obtained from a laser pulse diffusivity system designed and constructed at Sandia. A data reduction technique was used which simultaneously corrects for finite pulse time effects and sample heat losses by radiation. The specific heat was measured directly at temperatures below 680/sup 0/C using a commercial differential scanning calorimeter. For temperatures up to 1200/sup 0/C, the specific heat was determined by differentiating a curve fit to the measured sample enthalpy. The enthalpy was measured using a liquid argon vaporization calorimeter developed at Sandia. The thermal conductivity of the A517 steel was then calculated over the entire temperature range. A classical Curie transition was observed during measurements of both the diffusivity and enthalpy. The effect of this transition on the measured thermal conductivity is discussed.

Roth, E.P.

1983-01-01

260

Differential Scanning Calorimetric (DSC) Analysis of Rotary Nickel-Titanium (NiTi) Endodontic File (RNEF)  

NASA Astrophysics Data System (ADS)

To determine the variation of A f along the axial length of rotary nickel-titanium endodontic files (RNEF). Three commercial brands of 4% taper RNEF: GTX (#20, 25 mm, Dentsply Tulsa Dental Specialties, Tulsa, OK, USA), K3 (#25, 25 mm) and TF (Twisted File #25, 27 mm) (Sybron Kerr, Orange, CA, USA) were cut into segments at 4 mm increment from the working tip. Regional specimens were measured for differential heat-flow over thermal cycling, generally with continuous heating or cooling (5 °C/min) and 5 min hold at set temperatures (start, finish temperatures): GTX: -55, 90 °C; K3: -55, 45 °C; TF: -55, 60 °C; using differential scanning calorimeter. This experiment demonstrated regional differences in A f along the axial length of GTX and K3 files. Similar variation was not obvious in the TF samples. A contributory effect of regional difference in strain-hardening due to grinding and machining during manufacturing is proposed.

Wu, Ray Chun Tung; Chung, C. Y.

2012-12-01

261

Temperature-pressure phase diagram of URu2Si2 from resistivity measurements and ac calorimetry: Hidden order and Fermi-surface nesting  

NASA Astrophysics Data System (ADS)

By performing combined resistivity and calorimetric experiments under pressure, we have determined a precise temperature-pressure (T,P) phase diagram of the heavy fermion compound URu2Si2 . It will be compared with previous diagrams determined by elastic neutron diffraction and strain gauge techniques. At first glance, the low-pressure ordered phase referred to as hidden order is dominated by Fermi-surface nesting, which has strong consequences on the localized spin dynamics. The high-pressure phase is dominated by large moment antiferromagnetism (LMAF) coexisting with at least dynamical nesting needed to restore on cooling a local moment behavior. ac calorimetry confirms unambiguously that bulk superconductivity does not coexist with LMAF. URu2Si2 is one of the most spectacular examples of the dual itinerant and local character of uranium-based heavy fermion compounds.

Hassinger, E.; Knebel, G.; Izawa, K.; Lejay, P.; Salce, B.; Flouquet, J.

2008-03-01

262

Enhancement of gemcitabine affinity for biomembranes by conjugation with squalene: differential scanning calorimetry and Langmuir-Blodgett studies using biomembrane models.  

PubMed

Molecular interactions between gemcitabine, alone or conjugated with squalene to form the gem-squalene prodrug, with dimyristoylphosphatidylcholine have been investigated by differential scanning calorimetry and Langmuir film balance techniques to gain information about the interaction of gemcitabine and its prodrug with mammalian cell membranes and to evaluate the potential of liposomes as a delivery system for gemcitabine prodrugs. Phospholipids assembled as multilamellar vesicles or monolayers (at the air water interface) have been used as biomembrane models. Different interactions of gemcitabine, its prodrug, and squalene with the lipid were detected by dispersing the compounds in the MLV and were compared with kinetic experiments carried out to consider the ability of the examined compounds to dissolve in an aqueous medium, to migrate through it, and to be captured by multilamellar vesicles. Their ability to be released from drug-loaded liposomes and be taken up by empty vesicles mimicking biomembranes was also considered. Analysis of the differential scanning calorimetry curves reveals that gemcitabine has very little interaction with multilamellar vesicles whereas the gem-squalene prodrug strongly interacts with multilamellar vesicles. The kinetic experiments suggest that an aqueous medium does not permit the prodrug uptake by the biomembrane models, whereas it is allowed when gem-squalene is gradually released by the liposomes. The molecular area/surface pressure isotherms of the gemcitabine/lipid, gem-squalene/lipid, and pure compound monolayers, in agreement with the calorimetric results, indicate that gem-squalene interacts with the phospholipid monolayer with the squalene moiety in contact with the phospholipid chains and gemcitabine protruding in the aqueous medium. PMID:17765257

Castelli, Francesco; Sarpietro, Maria Grazia; Micieli, Dorotea; Stella, Barbara; Rocco, Flavio; Cattel, Luigi

2007-12-01

263

Phase transformation in NiTi studied by isothermal mechanical spectrometry  

Microsoft Academic Search

NiTi samples were studied by internal friction measurements and differential scanning calorimetry (DSC). DSC experiments were performed using a Mettler TA30 DSC with a controlled cooling\\/heating rate of 1 K\\/min, to determine the transformation heats (ÎH) and the characteristic transformation temperatures. It was necessary to expect a very long time (about one day) after each temperature change to obtain a

F. Déborde; V. Pelosin; A. Rivière

1995-01-01

264

Thermodynamic signature of secondary nano-emulsion formation by isothermal titration calorimetry.  

PubMed

The stabilization of oil in water nano-emulsions by means of a polymer coating is extremely important; it prolongs the shelf life of the product and makes it suitable for a variety of applications ranging from nutraceutics to cosmetics and pharmaceutics. To date, an effective methodology to assess the best formulations in terms of thermodynamic stability has yet to be designed. Here, we perform a complete physicochemical characterization based on isothermal titration calorimetry (ITC) compared to conventional dynamic light scattering (DLS) to identify polymer concentration domains that are thermodynamically stable and to define the degree of stability through thermodynamic functions depending upon any relevant parameter affecting the stability itself, such as type of polymer coating, droplet distance, etc. For instance, the method was proven by measuring the energetics in the case of two different biopolymers, chitosan and poly-L-lysine, and for different concentrations of the emulsion coated with poly-L-lysine. PMID:25396753

Fotticchia, Iolanda; Fotticchia, Teresa; Mattia, Carlo Andrea; Netti, Paolo Antonio; Vecchione, Raffaele; Giancola, Concetta

2014-12-01

265

Metal adsorption calorimetry and adhesion energies on clean single-crystal surfaces  

NASA Astrophysics Data System (ADS)

The heats of adsorption of metals have been measured calorimetrically for the first time on clean, single-crystalline surfaces. A pulse of metal vapor from a chopped atomic beam adsorbs onto an ultrathin single crystal's surface, causing a transient temperature rise. This heat input is detected by a pyroelectric polymer ribbon, which is gently touched to the back of the crystal during calorimetry. The sticking probability is measured by detecting the reflected fraction mass spectroscopically. The differential heat of adsorption is thus measured as a detailed function of coverage up through multilayer coverages. The integral heat of adsorption also provides the adhesion energy of the metal film, if the surface free energy of the clean metal surface is known. Adsorption and adhesion energies for metals (Pb or Cu) on clean Mo(100) and on well-defined surface oxides of Mo(100) and W(100) are reported.

Stuckless, J. T.; Starr, D. E.; Bald, D. J.; Campbell, Charles T.

1997-10-01

266

Combined FPPE-PTR Calorimetry Involving TWRC Technique. Theory and Mathematical Simulations  

NASA Astrophysics Data System (ADS)

Photopyroelectric calorimetry in the front detection configuration (FPPE) was combined with photothermal radiometry (PTR), in order to investigate dynamic thermal parameters of different layers of a detection cell. The layout of the detection cell consists of three layers: directly irradiated pyroelectric sensor, liquid layer, and solid backing material; and the scanning parameter is the thickness of the liquid layer (thermal-wave resonator cavity method). The theory developed for the two techniques indicates that both FPPE and PTR signals can lead, in the thermally thin regime for the sensor and liquid layer, to the direct measurement of the thermal diffusivity or effusivity of the sensor and/or liquid layer, or the thermal effusivity of the backing material. The two methods offer complementary results and/or reciprocally support each other.

Dadarlat, Dorin; Pop, Mircea Nicolae; Streza, Mihaela; Longuemart, Stephane; Depriester, Michael; Hadj Sahraoui, Abdelhak; Simon, Viorica

2010-12-01

267

Fast Scanning Calorimetry study of non-equilibrium relaxation in fragile organic liquids  

NASA Astrophysics Data System (ADS)

Fast scanning calorimetry (FSC), capable of heating rates in excess of 1000000 K/s, was combined with vapor deposition technique to investigate non-equilibrium relaxation in micrometer thick viscous liquid films of several organic compounds (e.g.2-ethyl-1-hexanol, Toluene, and 1-propanol) under high vacuum conditions. Rapid heating of samples, vapor deposited at temperatures above their standard glass softening transition (Tg), resulted in observable endotherms which onset temperatures were strongly dependent on heating rate and the deposition temperature. Furthermore, all of the studied compounds were characterized by distinct critical deposition temperatures at which observation of endotherm became impossible. Based on the results of these studies, we have developed a simple model which makes it possible to infer the equilibrium enthalpy relaxation times for liquids from FSC data. We will discuss implications of these studies for contemporary models of non-equilibrium relaxation in glasses and supercooled liquids.

Sadtchenko, Vlad; Bhattacharya, Deepanjan; O'Reilly, Liam

2013-03-01

268

Enthalpies of formation of borides of iron, cobalt, and nickel by solution calorimetry in liquid copper  

Microsoft Academic Search

The enthalpies of formation at 1385 ?2 K of the following crystalline borides have been determined by high temperature solution\\u000a calorimetry using liquid copper as the calorimetric solvent. Fe2B-67.87 ?8.05 kJ mol?1, Co2B -58.1 ?7.0 kJ mol?1, Ni2B -67.66 ?4.12 kJ ml?1, FeB-64.63 ?4.34 kJ mol?1, CoB -69.52 ?6.0 kJ mol?1, and NiB -40.2 ?3.77 kJ mol?1. The enthalpy of

Seichi Sato; O. J. Kleppa

1982-01-01

269

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

PubMed Central

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. PMID:19742177

Pagano, Bruno; Mattia, Carlo Andrea; Giancola, Concetta

2009-01-01

270

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

SciTech Connect

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.

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

2013-11-13

271

DNA heats up : Energetics of genome ejection from phage revealed by isothermal titration calorimetry  

E-print Network

Most bacteriophages are known to inject their double-stranded DNA into bacteria upon receptor binding in an essentially spontaneous way. This downhill thermodynamic process from the intact virion toward the empty viral capsid plus released DNA is made possible by the energy stored during active packaging of the genome into the capsid. Only indirect measurements of this energy have been available until now using either single-molecule or osmotic suppression techniques. In this paper, we describe for the first time the use of isothermal titration calorimetry to directly measure the heat released (or equivalently the enthalpy) during DNA ejection from phage lambda, triggered in solution by a solubilized receptor. Quantitative analyses of the results lead to the identification of thermodynamic determinants associated with DNA ejection. The values obtained were found to be consistent with those previously predicted by analytical models and numerical simulations. Moreover, the results confirm the role of DNA hydration in the energetics of genome confinement in viral capsids.

Meerim Jeembaeva; B. Jönsson; Martin Castelnovo; Alex Evilevitch

2010-01-06

272

Temperature Calibration for Optical Pyrometry in Containerless Systems Using Differential Scanning Calorimetry: Application to (-50)  

NASA Astrophysics Data System (ADS)

Accurate and precise measurements of the temperature are important for controlling conditions in any experimental design. In containerless processing, such as in electrostatic levitation and electromagnetic levitation, the temperature is typically measured using optical pyrometers. These are generally calibrated to the sample of interest by measuring the temperatures of phase transitions. The presence of multiple heat signatures, differences in emissivity for different phases, and inconsistencies in published phase diagrams can make this difficult. In this manuscript, a method for using differential scanning calorimetry measurements for calibration is outlined and applied to four Cu-Zr alloys from the eutectic to the line compound. This technique is particularly valuable for systems in which accurate phase diagram information is unavailable or inaccurate.

Bendert, J. C.; Pueblo, C. E.; Veligati, S.; Mauro, N. A.; Kelton, K. F.

2014-10-01

273

Irreversible Denaturation of Maltodextrin Glucosidase Studied by Differential Scanning Calorimetry, Circular Dichroism, and Turbidity Measurements  

PubMed Central

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). PMID:25548918

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

2014-01-01

274

An investigation of student thinking regarding calorimetry, entropy, and the second law of thermodynamics  

NSDL National Science Digital Library

This thesis constitutes an investigation into student understanding of concepts in thermal physics in an introductory calculus-based university physics course. Nearly 90% of students enrolled in the course had previous exposure to thermodynamics concepts in chemistry and/or high-school physics courses. The two major thrusts of this work are (1) an exploration of student approaches to solving calorimetry problems involving two substances with differing specific heats, and (2) a careful probing of student ideas regarding certain aspects of entropy and the second law of thermodynamics. We present extensive free-response, interview, and multiple-choice data regarding students' ideas, collected both before and after instruction from a diverse set of course semesters and instructors. For topics in calorimetry, we found via interviews that students frequently get confused by, or tend to overlook, the detailed proportional reasoning or algebraic procedures that could lead to correct solutions. Instead, students often proceed with semi-intuitive reasoning that at times may be productive, but more often leads to inconsistencies and non-uniform conceptual understanding. Our investigation of student thinking regarding entropy suggests that prior to instruction, students have consistent and distinct patterns of incorrect or incomplete responses that often persist despite deliberate and focused efforts by the instructor. With modified instruction based on research-based materials, significant learning gains were observed on certain key concepts, e.g., that the entropy of the universe increases for all non-ideal processes. The methodology for our work is described, the data are discussed and analyzed, and a description is given of goals for future work in this area.

Christensen, Warren M.

2013-02-13

275

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

NASA Astrophysics Data System (ADS)

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 from Cells to Cities - a Physicist's Search for Quantitative, Unified Theories of Biological and Social Structure and Dynamics,' inspired many interesting questions from the audience both after the talk and throughout the week during informal conversations. Calorimetry is extremely diverse: many different techniques may be employed in building the detector and also in extracting information from it. The topics of the Calorimeter Techniques sessions included high-rate liquid argon calorimeters, SiPM sensors, highly granular digital calorimeters, new crystals, and beam test and simulation results. In these pages, you will find exciting and sometimes contradicting points of view expressed, for example about fully sampling hadronic calorimeters. A rare astronomical event, the Venus transit, coincided with the second day of the conference. The participants enjoyed viewing Venus' trail across the sun with a solar telescope (H-alpha line at 656 nm). In Santa Fe, the interior ingress was at 16:23:04 and reached center at 19:27:04. The last transit occurred in 2004, and the next one will happen in 2117. In 1627, Johannes Kepler published data about the planetary orbits that predicted that Venus would pass directly between earth and the sun in 1631. Unfortunately Kepler died in 1630 and apparently nobody recorded the 1631 transit. The first recorded observation of a transit was in 1638, which Kepler had not predicted. Later, Jeremiah Horracks, an English astronomer, realized Kepler had made an error in his calculations. It was not until the Venus transit observations of 1769 that scientists measured the distance from the earth to the sun to be 95 million miles (actually 93 million miles or 149.7 million kilometers) based on the 1716 triangulation suggestion from Edmund Halley (of comet fame). It's interesting to remember that before the 18th century, one of the most vexing scientific puzzles, not unlike today's Higgs boson quest, was 'How far away is the Sun?' Although natural media such as Mediterranean water (ANTARES), Arctic ice (ARA, ARIANNA, ANITA, and others)

Akchurin, Nural

2012-12-01

276

Comparison of first pass bolus AIFs extracted from sequential 18F-FDG PET and DSC-MRI of mice  

NASA Astrophysics Data System (ADS)

Accurate kinetic modelling of in vivo physiological function using positron emission tomography (PET) requires determination of the tracer time-activity curve in plasma, known as the arterial input function (AIF). The AIF is usually determined by invasive blood sampling methods, which are prohibitive in murine studies due to low total blood volumes. Extracting AIFs from PET images is also challenging due to large partial volume effects (PVE). We hypothesise that in combined PET with magnetic resonance imaging (PET/MR), a co-injected bolus of MR contrast agent and PET ligand can be tracked using fast MR acquisitions. This protocol would allow extraction of a MR AIF from MR contrast agent concentration-time curves, at higher spatial and temporal resolution than an image-derived PET AIF. A conversion factor could then be applied to the MR AIF for use in PET kinetic analysis. This work has compared AIFs obtained from sequential DSC-MRI and PET with separate injections of gadolinium contrast agent and 18F-FDG respectively to ascertain the technique?s validity. An automated voxel selection algorithm was employed to improve MR AIF reproducibility. We found that MR and PET AIFs displayed similar character in the first pass, confirmed by gamma variate fits (p<0.02). MR AIFs displayed reduced PVE compared to PET AIFs, indicating their potential use in PET/MR studies.

Evans, Eleanor; Sawiak, Stephen J.; Ward, Alexander O.; Buonincontri, Guido; Hawkes, Robert C.; Adrian Carpenter, T.

2014-01-01

277

Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Thermal Properties of Organic Hydrocarbons  

ERIC Educational Resources Information Center

In first-year general chemistry undergraduate courses, thermodynamics and thermal properties such as melting points and changes in enthalpy ([Delta]H) and entropy ([Delta]S) of phase changes are frequently discussed. Typically, classical calorimetric methods of analysis are used to determine [Delta]H of reactions. Differential scanning calorimetry…

D'Amelia, Ronald; Franks, Thomas; Nirode, William F.

2007-01-01

278

Parallel nano-Differential Scanning Calorimetry: A New Device for Combinatorial Analysis of Complex nano-Scale Material Systems  

E-print Network

1 Parallel nano-Differential Scanning Calorimetry: A New Device for Combinatorial Analysis of Complex nano-Scale Material Systems Patrick James McCluskey, and Joost J. Vlassak Division of Engineering is presented for the combinatorial analysis of complex nano-scale material systems. The parallel nano

279

Thermodynamic characteristics of the acid-base equilibria of taurine in aqueous solutions, according to calorimetry data  

NASA Astrophysics Data System (ADS)

Enthalpies of the neutralization and protonation of taurine (HL) are measured by direct calorimetry at 298.15 K and ionic strengths of 0.3, 0.5, and 1.0 (KNO3). The standard thermodynamic characteristics of HL protolytic equilibria are calculated.

Gridchin, S. N.; Shekhanov, R. F.; Pyreu, D. F.

2015-02-01

280

Evaluation of three flame retardant (FR) grey cotton blend nonwoven fabrics using micro-scale combustion calorimetry  

Technology Transfer Automated Retrieval System (TEKTRAN)

Unbleached (grey or greige) cotton nonwoven (NW) fabrics (with 12.5% polypropylene scrim) were treated with three phosphate-nitrogen based FR formulations and evaluated with micro-scale combustion calorimetry (MCC). Heat release rate (HRR), Peak heat rate (PHRR), temperature at peak heat release ra...

281

On the accuracy of instantaneous gas exchange rates, energy expenditure, and respiratory quotient calculations obtained in indirect whole room calorimetry  

Technology Transfer Automated Retrieval System (TEKTRAN)

The molar balance equations of indirect calorimetry are treated from the point of view of cause-effect relationship where the gaseous exchange rates representing the unknown causes heed to be inferred from a known noisy effect – gaseous concentrations. Two methods of such inversion are analyzed. Th...

282

Protein-Water and Protein-Buffer Interactions in the Aqueous Solution of an Intrinsically Unstructured Plant Dehydrin: NMR Intensity and DSC Aspects  

Microsoft Academic Search

Proton NMR intensity and differential scanning calorimetry measurements were carried out on an intrinsically unstructured late embryogenesis abundant protein, ERD10, the globular BSA, and various buffer solutions to characterize water and ion binding of proteins by this novel combination of experimental approaches. By quantifying the number of hydration water molecules, the results demonstrate the interaction between the protein and NaCl

P. Tompa; P. Banki; M. Bokor; P. Kamasa; D. Kovacs; G. Lasanda; K. Tompa

2006-01-01

283

Calorimetric and thermomechanical properties of titanium-based orthodontic wires: DSC-DMA relationship to predict the elastic modulus.  

PubMed

Orthodontic treatment is strongly dependent on the loads developed by metal wires, and the choice of an orthodontic archwire should be based on its mechanical performance. The desire of both orthodontists and engineers would be to predict the mechanical behavior of archwires. To this aim, Gum Metal (Toyota Central R&L Labs., Inc.), TMA (ORMCO), 35°C Copper NiTi (SDS ORMCO), Thermalloy Plus (Rocky Mountain), Nitinol SE (3M Unitek), and NiTi (SDS ORMCO) were tested according to dynamic mechanical analysis and differential scanning calorimetry. A model was also developed to predict the elastic modulus of superelastic wires. Results from experimental tests have highlighted that superelastic wires are very sensitive to temperature variations occurring in the oral environment, while the proposed model seems to be reliable to predict the Young's modulus allowing to correlate calorimetric and mechanical data. Furthermore, Gum Metal wire behaves as an elastic material with a very low Young's modulus, and it can be particularly useful for the initial stage of orthodontic treatments. PMID:21343211

Laino, Giuliana; De Santis, Roberto; Gloria, Antonio; Russo, Teresa; Quintanilla, David Suárez; Laino, Alberto; Martina, Roberto; Nicolais, Luigi; Ambrosio, Luigi

2012-03-01

284

Chemical analysis of metal impurity distribution of zone-refined mercuric iodide by ICP-AES and DSC  

NASA Astrophysics Data System (ADS)

A mercuric iodide single crystal is being developed for X-ray and gamma-ray detector applications where high-purity starting material is required. Zone-refining processing has been proven to be an effective step in the purification of large amounts of mercuric iodide for crystal growth. In this study we used the Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) to identify and determine the distribution of impurity concentrations along the ampoule after zone-refining mercuric iodide. The results show that for Ag, Cu, Fe, Mg, Ca, Zn, Cr and Al, the zone-refining process does sweep the impurities to the last-to-freeze zone, due to an effective distribution coefficient, keff < 1. For Na, Ni, Cd, Mn and Pb the concentration gradient seems to be fairly independent of the position along the ingot. Differential Scanning Calorimetry was also employed to investigate the deviation from stoichiometry caused by the zone-refining process, and the results indicated that the first-to-freeze section is Hg-rich, and the middle section tends to become slightly Hg-rich, while the last-to-freeze section becomes I-rich.

Chen, K.-T.; Salary, L.; Burger, A.; Soria, E.; Antolak, A.; James, R. B.

285

Hydrolysis of post-consume poly(ethylene terephthalate) with sulfuric acid and product characterization by WAXD, 13C NMR and DSC  

Microsoft Academic Search

Post-consume PET was hydrolysed with commercial sulfuric acid (96%) with varying reaction times (5–120min). The structure of the material obtained was analysed by 13C NMR, DSC, and WAXD and the results were correlated with reaction time. 13C NMR shows a decrease in chain size with reaction time and an increase in the number of carboxyl groups at the end of

Gizilene M. de Carvalho; Edvani C. Muniz; Adley F. Rubira

2006-01-01

286

A study of pyrolysis and pyrolysis products of flame-retardant cotton fabrics by DSC, TGA, and PY–GC–MS  

Microsoft Academic Search

Study of thermal decompositions of cotton and flame-retardant cotton fabrics can assist understanding of fire-resistant functions of the materials. In this research, differential scanning calorimeter (DSC), thermogravimetric analysis (TGA) and pyrolysis–gas chromatography–mass spectroscopy (PY–GC–MS) were employed to investigate decomposition processes and decomposed products of flame-retardant treated (using an organo-phosphorus compound) and untreated cotton fibers in the pyrolysis. The thermal decomposition

Ping Zhu; Shuying Sui; Bing Wang; Kai Sun; Gang Sun

2004-01-01

287

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

NASA Astrophysics Data System (ADS)

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 (NbNx). 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.

Dechaumphai, Edward; Chen, Renkun

2014-09-01

288

Calorimetry and respirometry in guinea pigs in hydrox and heliox at 10-60 atm.  

PubMed

We used direct calorimetry and respirometry to measure the total rate of heat loss (Qsigma) and of oxygen consumption (VO2) in guinea pigs in 1-atm (0.1 MPa) air and at 10-60 atm in either heliox (98% He, 2% O2) or hydrox (98% H2, 2% O2). Our objective was to determine if the physiological responses to these two gas mixtures were different and, if so, whether the differences were attributable to the thermal characteristics of the gases alone or were confounded by additional mechanisms. At 10-40 atm, Qsigma and VO2 were not significantly different in the two gas mixtures, whereas at 60 atm, Qsigma and VO2 were significantly higher in heliox than in hydrox. The VO2/Qsigma ratio suggested that the animals were not in thermal equilibrium in hyperbaria. Based solely on the differing thermal properties of the gas mixtures, a mathematical model predicted a Qsigma that was higher in hydrox than in heliox at all pressures. Two plausible explanations are suggested: one is an adaptive lowering of the surface temperature as a physiological response of the animal to the thermally more stressful hydrox environment, and the other is related to the narcotic suppression of the animal's activity by hydrox. PMID:11041549

Fahlman, A; Kaveeshwar, J A; Tikuisis, P; Kayar, S R

2000-10-01

289

Binding of Ru(terpyridine)(pyridine)dipyridophenazine to DNA studied with polarized spectroscopy and calorimetry.  

PubMed

Linear and circular dichroism (LD and CD) spectroscopy as well as isothermal titration calorimetry (ITC) have been used to investigate the interaction of Ru(tpy)(py)dppz(2+) (tpy = 2,2':6',2''-terpyridyl; py = pyridine; dppz = dipyrido[3,2-a:2'3'-c]phenazine) with DNA, providing detailed information about the DNA binding thermodynamics and binding geometry of the metal complex. Flow LD, CD and isotropic absorption indicate that Ru(tpy)(py)dppz(2+) bind to DNA from the minor groove with the dppz ligand intercalated between base pairs, very similar to its chiral structural isomers ?- and ?-Ru(bpy)2dppz(2+) (bpy = 2,2'-bipyridine). A simple cooperative binding model with one binding geometry provide an excellent fit for calorimetric and absorption titration data. The values of the neighbor interaction thermodynamic parameters for Ru(tpy)(py)dppz(2+) suggest that complexes bound contiguously prefer to have their tpy ligands oriented towards the same strand. PMID:25406791

Mårtensson, Anna K F; Lincoln, Per

2015-02-10

290

Isothermal calorimetry: a predictive tool to model drug-propellant interactions in pressurized metered dose systems.  

PubMed

The purpose of this work was to evaluate gas perfusion isothermal calorimetry (ITC) as a method to characterize the physicochemical changes of active pharmaceutical ingredients (APIs) intended to be formulated in pressurized metered dose inhalers (pMDIs) after exposure to a model propellant. Spray dried samples of beclomethasone dipropionate (BDP) and salbutamol sulphate (SS) were exposed to controlled quantities of 2H,3H-decafluoropentane (HPFP) to determine whether ITC could be used as a suitable analytical method for gathering data on the behavioural properties of the powders in real time. The crystallization kinetics of BDP and the physiochemical properties of SS were successfully characterized using ITC and supported by a variety of other analytical techniques. Correlations between real and model propellant systems were also established using hydrofluoroalkane (HFA-227) propellant. In summary, ITC was found to be suitable for gathering data on the crystallization kinetics of BDP and SS. In a wider context, this work will have implications on the use of ITC for stability testing of APIs in HFA-based pMDIs. PMID:24325938

Ooi, Jesslynn; Gaisford, Simon; Boyd, Ben J; Young, Paul M; Traini, Daniela

2014-01-30

291

Probing the binding of procyanidin B3 to human serum albumin by isothermal titration calorimetry  

NASA Astrophysics Data System (ADS)

Proanthocyanidins are a mixture of monomers, oligomers, and polymers of flavan-3-ols that are widely distributed in the plant kingdom. One of the most widely studied proanthocyanidins is procyanidin B3. In this study, the interaction between procyanidin B3 and human serum albumin (HSA) was investigated using isothermal titration calorimetry (ITC). Thermodynamic investigations reveal that the hydrogen bond and van der Waals force are the major binding forces in the binding of procyanidin B3 to HSA. The binding of procyanidin B3 to HSA is driven by favorable enthalpy and unfavorable entropy. The obtained binding constant for procyanidin B3 with HSA is in the intermediate range and the equilibrium fraction of unbound procyanidin B3 fu > 90% at the physiological concentration of HSA shows that procyanidin B3 can be stored and transported from the circulatory system to reach its target site. The stoichiometric binding number n approximately equals to 1, suggesting that one molecule of procyanidin B3 combines with one molecule of HSA and no more procyanidin B3 binding to HSA occurs at the concentration used in this study.

Li, Xiangrong; Yan, Yunhui

2015-02-01

292

Real-Time Monitoring of Membrane-Protein Reconstitution by Isothermal Titration Calorimetry  

PubMed Central

Phase diagrams offer a wealth of thermodynamic information on aqueous mixtures of bilayer-forming lipids and micelle-forming detergents, providing a straightforward means of monitoring and adjusting the supramolecular state of such systems. However, equilibrium phase diagrams are of very limited use for the reconstitution of membrane proteins because of the occurrence of irreversible, unproductive processes such as aggregation and precipitation that compete with productive reconstitution. Here, we exemplify this by dissecting the effects of the K+ channel KcsA on the process of bilayer self-assembly in a mixture of Escherichia coli polar lipid extract and the nonionic detergent octyl-?-d-glucopyranoside. Even at starting concentrations in the low micromolar range, KcsA has a tremendous impact on the supramolecular organization of the system, shifting the critical lipid/detergent ratios at the onset and completion of vesicle formation by more than 2-fold. Thus, equilibrium phase diagrams obtained for protein-free lipid/detergent mixtures would be misleading when used to guide the reconstitution process. To address this issue, we demonstrate that, even under such nonequilibrium conditions, high-sensitivity isothermal titration calorimetry can be exploited to monitor the progress of membrane-protein reconstitution in real time, in a noninvasive manner, and at high resolution to yield functional proteoliposomes with a narrow size distribution for further downstream applications. PMID:24354292

2013-01-01

293

The kinetics of the beta to alpha transformation in unalloyed plutonium using differential scanning calorimetry  

SciTech Connect

Differential scanning calorimetry measurements, both isothermal and on cooling, were made during the {beta} {yields} {alpha} transformation of unalloyed plutonium. The calorimetric measurements, because they directly measure the rate of heat flow, provide a direct quantitative measure of the rate of the reaction. Isothermal measurements at temperatures from 56{degree} to 68{degree}C showed that the reaction required incubation times, presumably for nucleation of the alpha phase, of from 300 to 550 seconds. The reaction rate increased with decreasing temperature in agreement with results of prior studies. The measured value for the heat of the reaction also corroborated earlier findings. The fraction-transformed curves were analyzed using the Johnson, Mehl, Avrami model. Analysis showed clearly that the reaction kinetics do not fit this model. The Avrami exponent, instead of being constant as predicted, decreased continuously (by more than a factor of four) during the first 80% of the reaction. Possible reasons for this apparent deviation from classical transformation kinetics are discussed. Measurements in the temperature-scanning mode were made on a sample consisting of ten separate pieces of plutonium. With successive cooling cycles through the {beta} {yields} {alpha} transformation, the heat release peak changed in shape, width, and position. This effect is believed to be due to changes in the residual stresses in different pieces of the sample.

Cost, J.R.; Soderquist, S.D.

1993-12-31

294

Simultaneous Absorptance and Thermal-Diffusivity Determination of Optical Components with Laser Calorimetry Technique  

NASA Astrophysics Data System (ADS)

The laser calorimetry (LCA) technique is used to determine simultaneously the absorptances and thermal diffusivities of optical components. An accurate temperature model, in which both the finite thermal conductivity and the finite sample size are taken into account, is employed to fit the experimental temperature data measured with an LCA apparatus for a precise determination of the absorptance and thermal diffusivity via a multiparameter fitting procedure. The uniqueness issue of the multiparameter fitting is discussed in detail. Experimentally, highly reflective (HR) samples prepared with electron-beam evaporation on different substrates (BK7, fused silica, and Ge) are measured with LCA. For the HR-coated sample on a fused silica substrate, the absorptance is determined to be 15.4 ppm, which is close to the value of 17.6 ppm, determined with a simplified temperature model recommended in the international standard ISO11551. The thermal diffusivity is simultaneously determined via multiparameter fitting to be approximately 6.63 × 10-7 m2 · s-1 with a corresponding square variance of 4.8 × 10-4. The fitted thermal diffusivity is in reasonably good agreement with the literature value (7.5 × 10-7 m2 · s -1). Good agreement is also obtained for samples with BK7 and Ge substrates.

Wang, Yanru; Li, Bincheng

2012-11-01

295

Energetics of genome ejection from phage revealed by isothermal titration calorimetry  

NASA Astrophysics Data System (ADS)

It has been experimentally shown that ejection of double-stranded DNA from phage is driven by internal pressure reaching tens of atmospheres. This internal pressure is partially responsible for delivery of DNA into the host cell. While several theoretical models and simulations nicely describe the experimental data of internal forces either resisting active packaging or equivalently favoring spontaneous ejection, there are no direct energy measurements available that would help to verify how quantitative these theories are. We performed direct measurements of the enthalpy responsible for DNA ejection from phage ?, using Isothermal Titration Calorimetry. The phage capsids were ``opened'' in vitro by titrating ? into a solution with LamB receptor and the enthalpy of DNA ejection process was measured. In his way, enthalpy stored in ? was determined as a function of packaged DNA length comparing wild-type phage ? (48.5 kb) with a shorter ?-DNA length mutant (37.7 kb). The temperature dependence of the ejection enthalpy was also investigated. The values obtained were in good agreement with existing models and provide a better understanding of ds- DNA packaging and release mechanisms in motor-packaged viruses (e.g., tailed bacteriophages, Herpes Simplex, and adenoviruses).

Jeembaeva, Meerim; Jonsson, Bengt; Castelnovo, Martin; Evilevitch, Alex

2009-03-01

296

Accurate temperature model for absorptance determination of optical components with laser calorimetry  

SciTech Connect

In the international standard (International Organization for Standardization 11551) for measuring the absorptance of optical components (i.e., laser calorimetry), the absorptance is obtained by fitting the temporal behavior of laser irradiation-induced temperature rise to a homogeneous temperature model in which the infinite thermal conductivity of the sample is assumed. In this paper, an accurate temperature model, in which both the finite thermal conductivity and size of the sample are taken into account, is developed to fit the experimental temperature data for a more precise determination of the absorptance. The difference and repeatability of the results fitted with the two theoretical models for the same experimental data are compared. The optimum detection position when the homogeneous model is employed in the data-fitting procedure is also analyzed with the accurate temperature model. The results show that the optimum detection location optimized for a wide thermal conductivity range of 0.2-50W/m{center_dot}K moves toward the center of the sample as the sample thickness increases and deviates from the center as the radius and irradiation time increase. However, if the detection position is optimized for an individual sample with known sample size and thermal conductivity by applying the accurate temperature model, the influence of the finite thermal conductivity and sample size on the absorptance determination can be fully compensated for by fitting the temperature data recorded at the optimum detection position to the homogeneous temperature model.

Wang Yanru; Li Bincheng

2011-03-20

297

Thermodynamic analysis of Bacillus subtilis endospore protonation using isothermal titration calorimetry  

NASA Astrophysics Data System (ADS)

Bacterial proton and metal adsorption reactions have the capacity to affect metal speciation and transport in aqueous environments. We coupled potentiometric titration and isothermal titration calorimetry (ITC) analyses to study Bacillus subtilis spore-proton adsorption. We modeled the potentiometric data using a four and five-site non-electrostatic surface complexation model (NE-SCM). Heats of spore surface protonation from coupled ITC analyses were used to determine site specific enthalpies of protonation based on NE-SCMs. The five-site model resulted in a substantially better model fit for the heats of protonation but did not significantly improve the potentiometric titration model fit. The improvement observed in the five-site protonation heat model suggests the presence of a highly exothermic protonation reaction circa pH 7 that cannot be resolved in the less sensitive potentiometric data. From the log Ks and enthalpies we calculated corresponding site specific entropies. Log Ks and site concentrations describing spore surface protonation are statistically equivalent to B. subtilis cell surface protonation constants. Spore surface protonation enthalpies, however, are more exothermic relative to cell based adsorption suggesting a different bonding environment. The thermodynamic parameters defined in this study provide insight on molecular scale spore-surface protonation reactions. Coupled ITC and potentiometric titrations can reveal highly exothermic, and possibly endothermic, adsorption reactions that are overshadowed in potentiometric models alone. Spore-proton adsorption NE-SCMs derived in this study provide a framework for future metal adsorption studies.

Harrold, Zoë R.; Gorman-Lewis, Drew

2013-05-01

298

Thermal unfolding of staphylococcal nuclease and several mutant forms thereof studied by differential scanning calorimetry.  

PubMed Central

The effects of eight mutations on the thermodynamics of the reversible thermal unfolding of staphylococcal nuclease have been determined over a range of pH and protein concentration by means of differential scanning calorimetry. Variation of the protein concentration was included in our study because we found a significant dependence of the thermodynamics of protein unfolding on concentration. Values for the change in the standard free energy of unfolding, delta delta G0d, produced by the mutations in the pH range 5.0-7.0 varied from 1.9 kcal mol-1 (apparent stabilization) for H124L to -2.8 kcal mol-1 (apparent destabilization) for L25A. As has been observed in numerous other cases, there is no correlation in magnitude or sign between delta delta G0d and the corresponding values for delta delta Hd and T delta delta S0d, the latter quantities being in most cases much larger in magnitude than delta delta G0d. This fact emphasizes the difficulty in attempting to correlate the thermodynamic changes with structural changes observed by X-ray crystallography. PMID:8518730

Tanaka, A.; Flanagan, J.; Sturtevant, J. M.

1993-01-01

299

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

SciTech Connect

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.

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

2005-10-01

300

A novel optical calorimetry dosimetry approach applied to an HDR Brachytherapy source  

NASA Astrophysics Data System (ADS)

The technique of Digital Holographic Interferometry (DHI) is applied to the measurement of radiation absorbed dose distribution in water. An optical interferometer has been developed that captures the small variations in the refractive index of water due to the radiation induced temperature increase ?T. The absorbed dose D is then determined with high temporal and spatial resolution using the calorimetric relation D=c?T (where c is the specific heat capacity of water). The method is capable of time resolving 3D spatial calorimetry. As a proof-of-principle of the approach, a prototype DHI dosimeter was applied to the measurement of absorbed dose from a High Dose Rate (HDR) Brachytherapy source. Initial results are in agreement with modelled doses from the Brachyvision treatment planning system, demonstrating the viability of the system for high dose rate applications. Future work will focus on applying corrections for heat diffusion and geometric effects. The method has potential to contribute to the dosimetry of diverse high dose rate applications which require high spatial resolution such as microbeam radiotherapy (MRT) or small field proton beam dosimetry but may potentially also be useful for interface dosimetry.

Cavan, A.; Meyer, J.

2013-06-01

301

Effect of temperature on studtite stability: Thermogravimetry and differential scanning calorimetry investigations  

NASA Astrophysics Data System (ADS)

The main objective of this work is the study of the influence of temperature on the stability of the uranyl peroxide tetrahydrate (UO 2O 2 · 4H 2O) studtite, which may form on the spent nuclear fuel surface as a secondary solid phase. Preliminary results on the synthesis of studtite in the laboratory at different temperatures have shown that the solid phases formed when mixing hydrogen peroxide and uranyl nitrate depends on temperature. Studtite is obtained at 298 K, meta-studtite (UO 2O 2 · 2H 2O) at 373 K, and meta-schoepite (UO 3 · nH 2O, with n < 2) at 423 K. Because of the temperature effect on the stability of uranyl peroxides, a thermogravimetric (TG) study of studtite has been performed. The main results obtained are that three transformations occur depending on temperature. At 403 K, studtite transforms to meta-studtite, at 504 K, meta-studtite transforms to meta-schoepite, and, finally, at 840 K, meta-schoepite transforms to U 3O 8. By means of the differential scanning calorimetry the molar enthalpies of the transformations occurring at 403 and 504 K have been determined to be -42 ± 10 and -46 ± 2 kJ mol -1, respectively.

Rey, A.; Casas, I.; Giménez, J.; Quiñones, J.; de Pablo, J.

2009-03-01

302

Simulating SiD Calorimetry: Software Calibration Procedures and Jet Energy Resolution  

SciTech Connect

Simulated calorimeter performance in the SiD detector is examined. The software calibration procedures are described, as well as the perfect pattern recognition PFA reconstruction. Performance of the SiD calorimeters is summarized with jet energy resolutions from calorimetry only, perfect pattern recognition and the SiD PFA algorithm. Presented at LCWS08[1]. Our objective is to simulate the calorimeter performance of the SiD detector, with and without a Particle Flow Algorithm (PFA). Full Geant4 simulations using SLIC[2] and the SiD simplified detector geometry (SiD02) are used. In this geometry, the calorimeters are represented as layered cylinders. The EM calorimeter is Si/W, with 20 layers of 2.5mm W and 10 layers of 5mm W, segmented in 3.5 x 3.5mm{sup 2} cells. The HAD calorimeter is RPC/Fe, with 40 layers of 20mm Fe and a digital readout, segmented in 10 x 10mm{sup 2} cells. The barrel detectors are layered in radius, while the endcap detectors are layered in z(along the beam axis).

Cassell, Ron; /SLAC

2009-02-23

303

AC Calorimetry and Thermophysical Properties of Bulk Glass-Forming Metallic Liquids  

NASA Technical Reports Server (NTRS)

Thermo-physical properties of two bulk metallic glass forming alloys, Ti34Zr11Cu47Ni8 (VIT 101) and Zr57Nb5Ni12.6Al10CU15.4 (VIT 106), were investigated in the stable and undercooled melt. Our investigation focused on measurements of the specific heat in the stable and undercooled liquid using the method of AC modulation calorimetry. The VIT 106 exhibited a maximum undercooling of 140 K in free radiative cooling. Specific heat measurements could be performed in stable melt down to an undercooling of 80 K. Analysis of the specific heat data indicate an anomaly near the equilibrium liquidus temperature. This anomaly is also observed in y the temperature dependencies of the external relaxation time, the specific volume, and the surface tension; it is tentatively attributed to a phase separation in the liquid state. The VIT 101 specimen exhibited a small undercooling of about 50 K. Specific heat measurements were performed in the stable and undercooled melt. These various results will be combined with ground based work such as the measurement of T-T-T curves in the electrostatic levitator and low temperature viscosity and specific heat measurements for modeling the nucleation kinetics of these alloys.

Johnson, William L.

2000-01-01

304

The Utilization of HOPG based Graphene for a less costly and efficient replacement of platinum in Dye-Sensitized Solar Cells (DSC's)  

NASA Astrophysics Data System (ADS)

Dye-Sensitized Solar Cells (DSC) are also known as Graetzel cells after their inventor, Michael Graetzel, who invented them in 1991. DSCs are potential alternatives to the more conventional and expensive semiconductor p-n junction solar cells like silicon solar cells. In a Graetzel cell, light is absorbed by a sensitizing dye which is coupled to a wide band gap semiconductor (TiO2). Electric charges are liberated by the photon induced electron injection from the dye molecules into the conduction band of the semiconductor. The use of sensitizers in conjunction with the semiconductor oxide permits the absorption of a large portion of the terrestrial solar spectrum with near 10% conversion efficiency. In the ``traditional'' DSC, platinum metal is used as one of the counter electrode materials. In our research, graphene of various forms (from HOPG in specific) is utilized instead of costly platinum to replace the counter-electrode in the DSC's. HOPG also known as Higly Oriented Pyrolitic Graphite is being used to dry deposit graphene layers onto glass or FTO.

Pusko, Matthew P.

2012-10-01

305

Effect of dioxane on the hydration of human serum albumin as studied by isothermal calorimetry and IR spectroscopy  

Microsoft Academic Search

A comparison of isothermal calorimetry data on the interaction of human serum albumin with water in the presence and absence\\u000a of dioxane and of the isotherms of adsorption of vapors of water and dioxane on HSA as measured by IR spectroscopy made it\\u000a possible to suggest an experimental method for isolating the contribution from the organic solvent to the thermodynamic

V. A. Sirotkin; D. V. Korolev

2006-01-01

306

A differential scanning calorimetry study on the oxidation of C 12 -C 18 saturated fatty acids and their esters  

Microsoft Academic Search

The autoxidation of lauric, myristic, palmitic, and stearic acids, their ethyl esters, and palmitic and stearic triglycerides\\u000a was investigated by means of the isothermal and nonisothermal differential scanning calorimetry methods under oxygen flow.\\u000a The activation energies of oxidation of all investigated compounds were similar (106.0–134.3 kJ\\/mol) and did not depend on\\u000a length of the carbon chain. Kinetic parameters of start

G. Litwinienko; A. Daniluk; T. Kasprzycka-Guttman

1999-01-01

307

The influence of dioxane on the hydration of bovine pancreatic ?-chymotrypsin according to isothermal calorimetry and IR spectroscopy data  

NASA Astrophysics Data System (ADS)

The influence of dioxane on the thermochemical characteristics of the hydration of bovine pancreatic ?-chymotrypsin enzyme over the whole range of water thermodynamic activities was studied by comparing the isothermal calorimetry data on the thermochemistry of interaction between the enzyme and water in the presence and absence of dioxane and using the IR spectral data on the adsorption of water and organic solvent vapors on the protein.

Sirotkin, V. A.; Korolev, D. V.

2006-11-01

308

Characterizing water/rock interaction in simulated comet nuclei via calorimetry: Tool for in-situ science, laboratory analysis, and sample preservation  

NASA Technical Reports Server (NTRS)

Although results from the Giotto and Vega spacecraft flybys of comet P/Halley indicate a complex chemistry for both the ices and dust in the nucleus, carbonaceous chondrite meteorites are still regarded as useful analogs for the rocky components. Carbonaceous chondrites mixed with water enable simulation of water/rock interactions which may occur in cometary nuclei. Three general types of interactions can be expected between water and minerals at sub-freezing temperatures: heterogeneous nucleation of ice by insoluble minerals; adsorption of water vapor by hygroscopic phases; and freezing and melting point depression of liquid water sustained by soluble minerals. Two series of experiments were performed in a differential scanning calorimeter (DSC) with homogenized powders of the following whole-rock meteorites and comparison samples: Allende (CV3), Murchison (CM2), Orgueil (CI), Holbrook (L6), and Pasamonte (eucrite) meteorites as well as on peridotite (PCC-1, USGS), saponite (Sap-Ca-1, CMS), montmorillonite (STx-1, CMS), and serpentine (Franciscan Formation, California). Results are briefly discussed.

Allton, Judith H.; Gooding, James L.

1991-01-01

309

Energetics of formic acid conversion to adsorbed formates on Pt(111) by transient calorimetry.  

PubMed

Carboxylates adsorbed on solid surfaces are important in many technological applications, ranging from heterogeneous catalysis and surface organo-functionalization to medical implants. We report here the first experimentally determined enthalpy of formation of any surface bound carboxylate on any surface, formate on Pt(111). This was accomplished by studying the dissociative adsorption of formic acid on oxygen-presaturated (O-sat) Pt(111) to make adsorbed monodentate and bidentate formates using single-crystal adsorption calorimetry. The integral heat of molecular adsorption of formic acid on clean Pt(111) at 100 K is 62.5 kJ/mol at 0.25 monolayer (ML). On O-sat Pt(111), the integral heat of the dissociative adsorption of formic acid to make monodentate formate (HCOOmon,ad) plus the water-hydroxyl complex ((H2O-OH)ad) was found to be 76 kJ/mol at 3/8 ML and 100-150 K. Similarly, its integral heat of dissociative adsorption to make bidentate formate (HCOObi,ad) plus (H2O-OH)ad was 106 kJ/mol at 3/8 ML and 150 K. These heats give the standard enthalpies of formation of adsorbed monodentate and bidentate formate on Pt(111) to be -354 ± 5 and -384 ± 5 kJ/mol, respectively, and their net bond enthalpies to the Pt(111) surface to be 224 ± 13 and 254 ± 13 kJ/mol, respectively. Coverage-dependent enthalpies of formation were used to estimate the enthalpy of the elementary reaction HCOOHad ? HCOObi,ad + Had to be -4 kJ/mol at zero coverage and +24 kJ/mol at 3/8 ML. PMID:24512006

Silbaugh, Trent L; Karp, Eric M; Campbell, Charles T

2014-03-12

310

Digital holographic interferometry: A novel optical calorimetry technique for radiation dosimetry  

SciTech Connect

Purpose: To develop and demonstrate the proof-of-principle of a novel optical calorimetry method to determine radiation absorbed dose in a transparent medium. Methods: The calorimetric property of water is measured during irradiation by means of an interferometer, which detects temperature-induced changes in the refractive index that can be mathematically related to absorbed dose. The proposed method uses a technique called digital holographic interferometry (DHI), which comprises an optical laser interferometer setup and consecutive physical reconstruction of the recorded wave fronts by means of the Fresnel transform. This paper describes the conceptual framework and provides the mathematical basis for DHI dosimetry. Dose distributions from a high dose rate Brachytherapy source were measured by a prototype optical setup to demonstrate the feasibility of the approach. Results: The developed DHI dosimeter successfully determined absorbed dose distributions in water in the region adjacent to a high dose rate Brachytherapy source. A temperature change of 0.0381 K across a distance of 6.8 mm near the source was measured, corresponding to a dose of 159.3 Gy. The standard deviation in a typical measurement set was ±3.45 Gy (corresponding to an uncertainty in the temperature value of ±8.3 × 10{sup ?4} K). The relative dose fall off was in agreement with treatment planning system modeled data. Conclusions: First results with a prototype optical setup and a Brachytherapy source demonstrate the proof-of-principle of the approach. The prototype achieves high spatial resolution of approximately 3 × 10{sup ?5} m. The general approach is fundamentally independent of the radiation type and energy. The sensitivity range determined indicates that the method is predominantly suitable for high dose rate applications. Further work is required to determine absolute dose in all three dimensions.

Cavan, Alicia, E-mail: alicia.cavan@cdhb.health.nz [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand and Christchurch Hospital, Private Bag 4710, Christchurch 8140 (New Zealand)] [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140, New Zealand and Christchurch Hospital, Private Bag 4710, Christchurch 8140 (New Zealand); Meyer, Juergen, E-mail: juergen@uw.edu [Department of Radiation Oncology, University of Washington, 1959 Northeast Pacific Street, Box 356043, Seattle, Washington 98195 (United States)] [Department of Radiation Oncology, University of Washington, 1959 Northeast Pacific Street, Box 356043, Seattle, Washington 98195 (United States)

2014-02-15

311

Factors contributing to increased energy expenditure in thermal injury: a review of studies employing indirect calorimetry.  

PubMed

In summary, a remarkably close agreement exists for the mean MEE measured in 28 studies of severe burn trauma. This is especially surprising given the variability in sample sizes, measurement techniques, study designs, and DPBs studied. The mean MEE calculated from the data published in these reports is listed in the final column of Table I. For more than 450 cases, an unweighted MEE is 2750 +/- 85 kcal/day. For those studies prior to 1980, the mean MEE exceeds 3000 kcal/day in eight of 14 reports vs only two of 14 published after 1980. Even so, the mean MEE for the pre-1980 reports differs by only 200 kcal/day (2960 +/- 120, n = 14). The accepted notion that the degree of elevation in MEE is in proportion to the % BSAB up to about 60% BSAB is useful in a general sense but must be applied with caution. The recent studies, which include proportionately more burns exceeding 80% BSAB, suggest an elevation in MEE in these cases. Nevertheless, a physiologic plateau apparently exists at or slightly below 2 x normal RMR at the peak of MEE. The magnitude of the MEE response results from an undefined interaction among several factors of which some have been examined while others such as inflammatory mediators are only beginning to receive study. The contributions to reduction in MEE from interventions to control cardiac output and peripheral cooling, core temperature, evaporative water (heat) loss, and substrate cycling have been reviewed. The importance of indirect calorimetry in patient care is highlighted by the large variability in similarly injured individuals and in the unexplained component of regression analyses.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2273535

Cunningham, J J

1990-01-01

312

Validity of Six Activity Monitors in Chronic Obstructive Pulmonary Disease: A Comparison with Indirect Calorimetry  

PubMed Central

Reduced physical activity is an important feature of Chronic Obstructive Pulmonary Disease (COPD). Various activity monitors are available but their validity is poorly established. The aim was to evaluate the validity of six monitors in patients with COPD. We hypothesized triaxial monitors to be more valid compared to uniaxial monitors. Thirty-nine patients (age 68±7years, FEV1 54±18%predicted) performed a one-hour standardized activity protocol. Patients wore 6 monitors (Kenz Lifecorder (Kenz), Actiwatch, RT3, Actigraph GT3X (Actigraph), Dynaport MiniMod (MiniMod), and SenseWear Armband (SenseWear)) as well as a portable metabolic system (Oxycon Mobile). Validity was evaluated by correlation analysis between indirect calorimetry (VO2) and the monitor outputs: Metabolic Equivalent of Task [METs] (SenseWear, MiniMod), activity counts (Actiwatch), vector magnitude units (Actigraph, RT3) and arbitrary units (Kenz) over the whole protocol and slow versus fast walking. Minute-by-minute correlations were highest for the MiniMod (r?=?0.82), Actigraph (r?=?0.79), SenseWear (r?=?0.73) and RT3 (r?=?0.73). Over the whole protocol, the mean correlations were best for the SenseWear (r?=?0.76), Kenz (r?=?0.52), Actigraph (r?=?0.49) and MiniMod (r?=?0.45). The MiniMod (r?=?0.94) and Actigraph (r?=?0.88) performed better in detecting different walking speeds. The Dynaport MiniMod, Actigraph GT3X and SenseWear Armband (all triaxial monitors) are the most valid monitors during standardized physical activities. The Dynaport MiniMod and Actigraph GT3X discriminate best between different walking speeds. PMID:22745715

Louvaris, Zafeiris; Giavedoni, Santiago; Burtin, Chris; Langer, Daniel; Wilson, Frederick; Rabinovich, Roberto; Vogiatzis, Ioannis; Hopkinson, Nicholas S.; Troosters, Thierry

2012-01-01

313

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

NASA Astrophysics Data System (ADS)

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, ?HITCi, entropy, ?SITCi, Gibbs energy, ?GITCi, 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.

Barbosa, Silvia; Taboada, Pablo; Mosquera, Victor

2005-04-01

314

The Effect of Pulse Sequence Parameters and Contrast Agent Dose on Percentage Signal Recovery in DSC-MRI: Implications for Clinical Applications  

PubMed Central

BACKGROUND AND PURPOSE Both technical and pathophysiologic factors affect PSR in DSC-MR imaging. We aimed to determine how TE, flip angle (?), and contrast dose impact PSR in high-grade gliomas. MATERIALS AND METHODS We retrospectively computed PSR maps for 22 patients with high-grade gliomas, comparing 3 DSC-MR imaging methods by using single-dose gadodiamide without preload administration: A (n = 7), ? = 35°, TE = 54 ms; B (n = 5), ? = 72°, TE = 30 ms; C (n = 10), ? = 90°, TE = 30 ms. Methods A–C served as preload for subsequent dynamic imaging using method D (method C parameters but with double-dose contrast). We compared first- and second-injection tumor PSR for methods C and D (paired t test) and tumor PSR for both injections grouped by the first-injection acquisition method (3-group nonparametric 1-way ANOVA). We compared PSR in tumor and normal brain for each first- and second-injection method group (paired t test). RESULTS First-injection PSR in tumor and normal brain differed significantly for methods B (P = .01) and C (P = .05), but not A (P = .71). First-injection tumor PSR increased with T1 weighting with a significant main effect of method groupings (P = .0012), but there was no significant main effect for first-injection normal brain (P = .93), or second-injection tumor (P = .95) or normal brain (P = .13). In patients scanned with methods C and D, first-injection PSR significantly exceeded second-injection PSR for tumor (P = .037) and normal brain (P < .001). CONCLUSIONS PSR strongly depends on the T1 weighting of DSC-MR imaging, including pulse sequence (TE, ?) and contrast agent (dose, preload) parameters, with implications for protocol design and the interpretation and comparison of PSR values across tumor types and imaging centers. PMID:23413249

Boxerman, J.L.; Paulson, E.S.; Prah, M.A.; Schmainda, K.M.

2014-01-01

315

Use of DSC and DMA to Study Rubber Crystallization as a Possible Cause for a Tear in a Neoprene Glove Used in a Space Shuttle Pressurized Astronaut Suit  

NASA Technical Reports Server (NTRS)

The Advanced Crew Escape Suit (ACES) is a pressurized suit normally worn by astronauts during launch and landing phases of Space Shuttle operations. In 2008, a large tear (0.5 -1 in. long, between the pinky and ring finger) in the ACES left-hand glove made of neoprene latex rubber was found during training for Shuttle flight STS-124. An investigation to help determine the cause(s) of the glove tear was headed by the NASA Johnson Space Center (JSC) in Houston, Texas. Efforts at JSC to reproduce the actual glove tear pattern by cutting/tearing or rupturing were unsuccessful. Chemical and material property data from JSC such as GC-MS, FTIR, DSC and TGA mostly showed little differences between samples from the torn and control gloves. One possible cause for the glove tear could be a wedding ring/band worn by a male astronaut. Even with a smooth edge, such a ring could scratch the material and initiate the tear observed in the left-hand glove. A decision was later made by JSC to not allow the wearing of such a ring during training or actual flight. Another possible cause for the ACES glove tear is crystallinity induced by strain in the neoprene rubber over a long period of time and use. Neoprene is one several elastomeric materials known to be susceptible to crystallization, and such a process is accelerated with exposure of the material to cold temperatures plus strain. When the temperature is lowered below room temperature, researchers have shown that neoprene crystallization may be maintained at temperatures as high as 45-50 F, with a maximum crystallization rate near 20-25 F (1). A convenient conditioning temperature for inducing neoprene crystallization is a typical freezer that is held near 0 F. For work at the NASA Marshall Space Flight Center (MSFC), samples were cut from several areas/locations (pinky/ring finger crotch, index finger and palm) on each of two pairs of unstrained ACES gloves for DSC and DMA thermal analysis testing. The samples were conditioned in a freezer for various times up to about 14 days. Some rectangular conditioned samples were unstrained, while most were subjected to strains up to 250% with the aid of two slotted aluminum blocks and two aluminum clamps per sample. Trends were observed to correlate DSC data (heat of fusion) and DMA data (linear CTE and stress for iso-strain testing) with: (a) sample location on each glove; and (b) level of strain during conditioning. Control samples cut as is from each glove location were also tested by DSC and DMA.

Wingard, Doug

2009-01-01

316

Development of crystal scintillators for calorimetry in high energy and astroparticle physics  

NASA Astrophysics Data System (ADS)

Here we describe application of the low-thermal gradient Chozchralski method to grow high quality radiopure cadmium tungstate crystal scintillators from enriched isotopes 106Cd and 116Cd, development of zinc molybdate from enriched 100Mo, highly radiopure zinc tungstate for double beta and dark matter experiments, production of bismuth germinate for frontier experiments in high energy physics.

Grigoriev, D. N.; Danevich, F. A.; Shlegel, V. N.; Vasiliev, Ya V.

2014-09-01

317

Enthalpy of formation of talc Mg3[Si4O10](OH)2 according to dissolution calorimetry  

NASA Astrophysics Data System (ADS)

A thermochemical study of natural talc was performed by high-temperature melt dissolution calorimetry on a Tian-Calvet calorimeter. Based on the total values of the increment in enthalpy upon heating the sample from room temperature to 973 K, and of the dissolution enthalpy at 973 K measured in this work for talc and gibbsite (along with those determined for tremolite, brucite, and their corresponding oxides), the enthalpy of formation was calculated for talc composed of elements, Mg3[Si4O10](OH)2, at 298.15 K: ?f H {el/o}(298.15 K) = -5900.6 ± 4.7 kJ/mol.

Ogorodova, L. P.; Kiseleva, I. A.

2011-09-01

318

Temperature-modulated calorimetry of the frequency dependence of the glass transition of poly(ethylene terephthalate) and ....  

SciTech Connect

Temperature-modulated differential scanning calorimetry, TMDSC, is new technique that permits to measure the apparent heat capacity vs modulation frequency. The method is briefly described and a quasi- isothermal measurement method is used to derive the kinetic parameters for PET and PS. A first-order kinetics expression was used to describe the approach to equilibrium and point out the limits caused by asymmetry and cooperativity of the kinetics. Use of a complex description of heat capacity and entropy is discussed. Activation energies vary from 75 to 350 kJ/mol, dependent on thermal pretreatment and the preexponential factor is correlated with the activation energy.

Wunderlich, B.; Okazaki, I. [Oak Ridge National Lab., TN (United States)] [Tennessee Univ., Knoxville, TN (United States). Dept. of Chemistry

1997-03-01

319

Measurement of the enthalpies of formation of ZrPt 3 and HfPt 3 by fluorine bomb calorimetry  

Microsoft Academic Search

The enthalpies of formation of ZrPt3 and HfPt3 were determined by fluorine combustion calorimetry. The results (?Hf\\u000a o\\u000a 298 (ZrPt3) = - 30.5 2.0 kcal\\/g atom and ?Hf\\u000a o\\u000a 298 (HfPt3) = - 33.0 2.5 kcal\\/g atom) support the predictions of the Engel Brewer Correlation of metals. The unusually large heats\\u000a of formation are considered to be caused by a

V. Srikrishnan; P. J. Ficalora

1974-01-01

320

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

NASA Astrophysics Data System (ADS)

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 (?c ˜ 600 Ks-1) and heating rate (?h ˜ 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.

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

2014-06-01

321

Observation of subtle dynamic transitions by a combination of neutron scattering, X-ray diffraction and DSC: a case study of the monoclinic L-cysteine.  

PubMed

The paper illustrates the benefit of combining several experimental techniques (incoherent elastic and inelastic neutron scattering, DSC, and X-ray diffraction) to study subtle dynamic transitions in a biologically important system, probing a broad time (frequency) range of the molecular motions in a wide temperature interval of 2-300K. As a case study the crystalline form (a monoclinic polymorph) of l-cysteine ((+)NH(3)-CH(CH(2)SH)-COO(-)) - an essential amino acid - has been selected. Crystals of amino acids are widely used to mimic important structural and dynamic features of peptides. The conformational lability of cysteine and the dynamics of the thiol-side chains are known to account for various phase transitions in the crystalline state and for the conformational transitions important for the biological function in the peptides. The effect of temperature on the monoclinic polymorph of l-cysteine, metastable at ambient conditions, has been studied for the first time. A dynamical transition at about 150K, marking a crossover of the molecular fluctuations between harmonic and non-harmonic dynamical regimes, was evidenced by evaluating the evolution of the mean-square displacement obtained from the elastic fixed window approach using the backscattering spectrometer IN10 located at the ILL. Although this transition does not manifest itself in the DSC, it was clearly observed by incoherent inelastic neutron scattering. By analyzing the dynamical susceptibility contribution (chi''(omega)) obtained using IN6 also at ILL we were able to evidence another relaxation process at a different time scale. The disordered soft l-cysteine structure has an excess of inelastic scattering at about 3meV, analogous to the "boson peak" observed in glass-like materials and proteins. High-precision X-ray diffraction has revealed an anomaly in the changes of selected unit cell parameters and volume at about 240K. PMID:20189291

Bordallo, Heloisa N; Boldyreva, Elena V; Fischer, Jennifer; Koza, Michael Marek; Seydel, Tilo; Minkov, Vasily S; Drebushchak, Valery A; Kyriakopoulos, Antonios

2010-05-01

322

Characterization of Dynamics in Complex Lyophilized Formulations: I. Comparison of Relaxation Times Measured by Isothermal Calorimetry with Data Estimated from the Width of the Glass Transition Temperature Region  

PubMed Central

The purposes of this study are to characterize the relaxation dynamics in complex freeze dried formulations and to investigate the quantitative relationship between the structural relaxation time as measured by thermal activity monitor (TAM) and that estimated from the width of the glass transition temperature (?Tg). The latter method has advantages over TAM because it is simple and quick. As part of this objective, we evaluate the accuracy in estimating relaxation time data at higher temperatures (50°C and 60°C) from TAM data at lower temperature (40°C) and glass transition region width (?Tg) data obtained by differential scanning calorimetry. Formulations studied here were hydroxyethyl starch (HES)-disaccharide, HES-polyol and HES-disaccharide-polyol at various ratios. We also re-examine, using TAM derived relaxation times, the correlation between protein stability (human growth hormone, hGH) and relaxation times explored in a previous report, which employed relaxation time data obtained from ?Tg. Results show that most of the freeze dried formulations exist in single amorphous phase, and structural relaxation times were successfully measured for these systems. We find a reasonably good correlation between TAM measured relaxation times and corresponding data obtained from estimates based on ?Tg, but the agreement is only qualitative. The comparison plot showed that TAM data is directly proportional to the 1/3 power of ?Tg data, after correcting for an offset. Nevertheless, the correlation between hGH stability and relaxation time remained qualitatively the same as found with using ?Tg derived relaxation data, and it was found that the modest extrapolation of TAM data to higher temperatures using ?Tg method and TAM data at 40°C resulted in quantitative agreement with TAM measurements made at 50 °C and 60 °C, provided the TAM experiment temperature is well below the Tg of the sample. PMID:23608636

Chieng, Norman; Mizuno, Masayasu; Pikal, Michael

2013-01-01

323

Characterization of Rabbit Ear Skin as a Skin Model for in vitro Transdermal Permeation Experiments: Histology, Lipid Composition and Permeability  

Microsoft Academic Search

Aim: The aim of this work was to characterize rabbit ear skin in view of its use in transdermal permeation experiments. Method: The characterization included histological analysis of the tissue, qualitative and quantitative analysis of stratum corneum (SC) lipids, differential scanning calorimetry and permeation experiments (caffeine, nicotinamide, progesterone). As a reference, pig ear skin was used. Results: The results obtained

S. Nicoli; C. Padula; V. Aversa; B. Vietti; P. W. Wertz; A. Millet; F. Falson; P. Govoni; P. Santi

2008-01-01

324

Interaction of phloretin with membranes: on the mode of action of phloretin at the water-lipid interface  

Microsoft Academic Search

The interaction of phloretin with single lipid bilayers on a spherical support and with multilamellar vesicles was studied\\u000a by differential scanning calorimetry (DSC) and nuclear magnetic resonance (NMR). The results indicated that phloretin interacts\\u000a with the lipid layer and changes its structural parameters. In DSC experiments, phloretin in its neutral form strongly decreased\\u000a the lipid phase transition temperature and slightly

Richard Cseh; Michael Hetzer; Kristina Wolf; Jürgen Kraus; Gerhard Bringmann; Roland Benz

2000-01-01

325

Negative pressure-temperature slopes for reactions forming MgSiO3 perovskite from calorimetry  

Microsoft Academic Search

A new and sensitive differential drop solution calorimetric technique was developed for very small samples. A single experiment using one 5.18-milligram sample of perovskite, synthesized at 25 GPa and 1873 Kelvin, gave 110.1 + or - 4.1 kilojoules\\/mole for the enthalpy of the ilmenite-perovskite transition in MgSiO3. The thermodynamics of the reaction of MgSiO3 (ilmenite) to MgSiO3 (perovskite) and of

E. Ito; M. Akaogi; L. Topor; A. Navrotsky

1990-01-01

326

Density functional theory, molecular dynamics, and differential scanning calorimetry study of the RbF-CsF phase diagram  

NASA Astrophysics Data System (ADS)

A multiscale modeling approach is developed to compute the phase diagram of the RbF-CsF binary system. The mixing enthalpies of the (Rb,Cs)F solid and liquid solutions are evaluated using density functional theory and classical molecular dynamics calculations, respectively. For the solid solution, 18 different configurations are studied with density functional theory and the surrounded atom model is applied in order to compute the configurational partition function. We also measure the solidus and liquidus equilibria using differential scanning calorimetry. Finally the RbF-CsF phase diagram is constructed using the calculated excess free enthalpies of the solid and liquid solutions and a very good agreement with our experimental data is found.

Beneš, O.; Zeller, Ph.; Salanne, M.; Konings, R. J. M.

2009-04-01

327

Calorimetry study of the synthesis of amorphous Ni-Ti alloys by mechanical alloying. [Ni33 Ti67  

SciTech Connect

We synthesized amorphous Ni/sub 33/Ti/sub 67/ alloy powder by ball milling (a) a mixture of elemental nickel and titanium powders and (b) powders of the crystalline intermetallic NiTi/sub 2/. We characterized the reaction products as a function of ball-milling time by differential scanning calorimetry and x-ray diffraction. The measurements suggest that in process (a) the amorphous alloy forms by a solid-state interdiffusion reaction at the clean Ni/Ti interfaces generated by the mechanical attrition. In process (b), the crystalline alloy powder stores energy in the form of chemical disorder and lattice and point defects. The crystal-to-amorphous transformation occurs when the stored energy reaches a critical value. The achievement of the critical stored energy competes with the dynamic recovery of the lattice. 23 refs., 7 figs.

Schwarz, R.B.; Petrich, R.R.

1988-01-01

328

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

PubMed

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. PMID:25168090

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

2014-08-27

329

Combined FPPE-PTR Calorimetry Involving TWRC Technique II. Experimental: Application to Thermal Effusivity Measurements of Solids  

NASA Astrophysics Data System (ADS)

Photopyroelectric calorimetry in the front detection configuration (FPPE) and photothermal radiometry (PTR) were simultaneously used, together with the thermal-wave resonator cavity method (TWRC), in order to investigate the thermal effusivity of solids inserted as backing layers in a detection cell. A new combined FPPE-PTR-TWRC setup was designed. It was demonstrated experimentally that the PTR technique, combined with the TWRC method, is able to provide calorimetric information about the third layer of a detection cell. Applications on solids with different values of the thermal effusivity (starting from metals, down to thermal isolators) are presented. The values of the thermal effusivity obtained with the PTR technique are similar to those obtained with the PPE technique, and in agreement with literature values; the two methods reciprocally support each other. The accuracy of both methods is higher when the values of the thermal effusivity of the backing layer and coupling fluid are close.

Dadarlat, Dorin; Pop, Mircea Nicolae; Streza, Mihaela; Longuemart, Stephane; Depriester, Michael; Sahraoui, Abdelhak Hadj; Simon, Viorica

2011-10-01

330

Glass softening, crystallization, and vaporization of nano-aggregates of Amorphous Solid Water: Fast Scanning Calorimetry studies  

E-print Network

Fast scanning calorimetry (FSC) was employed to investigate glass softening dynamics in amorphous solid water (ASW) nano-aggregates with thicknesses ranging from 2 to 20 nm. ASW nano-aggregates were prepared by vapor-deposition on the surface of a tungsten filament near 141 K and then heated at a rate of 100 kK/s. The resulting thermogram complex endo- and exothermal features were analyzed using a simple model. The results of the analysis show that glass softening of ASW nano-aggregates takes place at 160 K and vaporization of ASW nano-aggregates can take place at temperatures as low as 185 K. The results of these studies are discussed in conjunction with results of past studies of glass softening dynamics in water in various confining geometries.

Deepanjan Bhattacharya; Liam OReilly; Vlad Sadtchenko

2014-10-31

331

Standard enthalpies of formation of some 3d transition metal silicides by high temperature direct synthesis calorimetry  

Microsoft Academic Search

The standard enthalpies of formation of some 3d transition metal silicides have been measured by high temperature direct synthesis calorimetry at 1473±2 K. The following results, in kJ (mole of atoms)?1, are reported: ScSi: (?82.3±2.1); TiSi: (?72.6±1.9); Ti5Si3: (?73.8±2.0); Ti5Si4: (?78.5±2.1); V5Si3: (?59.0±2.0); V3Si: (?46.4±1.5); Cr5Si3: (?33.6±1.0); Cr3Si: (?27.2±1.1); CrSi: (?34.2±1.6); Mn5Si3: (?34.0±1.2); MnSi: (?39.4±1.7); FeSi: (?38.6±1.8); CoSi: (?49.3±1.3); Co2Si:

S. V Meschel; O. J Kleppa

1998-01-01

332

Effect of different dextrose equivalent of maltodextrin on the interactions with anionic surfactant in an isothermal titration calorimetry study.  

PubMed

Isothermal titration calorimetry (ITC) was used to study interactions between an anionic surfactant (sodium dodecyl sulfate, SDS) and maltodextrins with different dextrose equivalents (DE) in a buffer solution (pH 7.0, 10 mM NaCl, 20 mM Trizma, 30.0 degrees C). The interaction between SDS and maltodextrin was exothermic, which was attributed to incorporation of the hydrocarbon tail of the surfactant into a helical coil formed by the maltodextrin molecules. ITC measurements indicated that the number of SDS molecules bound per gram of maltodextrin increased with decreasing maltodextrin DE, i.e., increasing molecular weight. It was proposed that SDS only binds to maltodextrin molecules that have a DE greater than 10 glucose units. PMID:14664550

Wangsakan, Apiradee; Chinachoti, Pavinee; McClements, D Julian

2003-12-17

333

Measuring thermal diffusivity of mechanical and optical grades of polycrystalline diamond using an AC laser calorimetry method  

SciTech Connect

Because of its extremely high thermal conductivity, measuring the thermal conductivity or diffusivity of optical-grade diamond can be challenging. Various methods have been used to measure the thermal conductivity of thick diamond films. For the purposes of commercial quality control, the AC laser calorimetry method is appealing because it enables fairly rapid and convenient sample preparation and measurement. In this paper, the method is used to measure the thermal diffusivity of optical diamond. It is found that sample dimensions and measurement parameters are critical, and data analysis must be performed with great care. The results suggest that the method as it is applied to optical-grade diamond could be enhanced by a more powerful laser, higher frequency beam modulation, and post-processing based on 2D thermal simulation.

Rule, Toby D. [II-VI Incorporated; Cai, Wei [ORNL; Wang, Hsin [ORNL

2013-01-01

334

Transformation from continuous-to-isothermal aging applied on a maraging steel  

Microsoft Academic Search

The advantage of continuous Differential Scanning Calorimetry (DSC) experiments is the possibility of the precise determination of a reaction's enthalpy, the corresponding transition temperatures as well as a material's heat capacity. Additionally, continuous experiments are usually less time-consuming than isothermal procedures. On the contrary, in industry steels are subjected to isothermal aging treatments in order to obtain the desired mechanical

S. Primig; H. Leitner

2010-01-01

335

A DSC investigation on the influence of gemini surfactant stereochemistry on the organization of lipoplexes and on their interaction with model membranes.  

PubMed

Previous investigations showed that the extent of DNA condensation and the efficiency in the transfection of liposomes formulated with 1,2-dimyristoyl-sn-glycero-phosphocholine and cationic stereomeric gemini surfactants depend heavily on the stereochemistry of the gemini. The influence of the stereochemistry on the interaction of lipoplexes with zwitterionic and anionic cell membrane models was investigated by differential scanning calorimetry to rationalize their different biological behavior. Further, the thermotropic behavior of the corresponding liposomes and of the spontaneous self-assemblies of gemini surfactants in the presence and in the absence of DNA was evaluated to correlate the physicochemical properties of lipoplexes and the stereochemistry of the cationic component. The obtained results show that the stereochemistry of the gemini surfactant controls lipoplexes organization and their mode and kinetic of interaction with different cell membrane models. PMID:23194898

Aleandri, S; Bonicelli, M G; Giansanti, L; Giuliani, C; Ierino, M; Mancini, G; Martino, A; Scipioni, A

2012-12-01

336

Stereo-Selectivity of Human Serum Albumin to Enantiomeric and Isoelectronic Pollutants Dissected by Spectroscopy, Calorimetry and Bioinformatics  

PubMed Central

1–naphthol (1N), 2–naphthol (2N) and 8–quinolinol (8H) are general water pollutants. 1N and 2N are the configurational enantiomers and 8H is isoelectronic to 1N and 2N. These pollutants when ingested are transported in the blood by proteins like human serum albumin (HSA). Binding of these pollutants to HSA has been explored to elucidate the specific selectivity of molecular recognition by this multiligand binding protein. The association constants (Kb) of these pollutants to HSA were moderate (104–105 M?1). The proximity of the ligands to HSA is also revealed by their average binding distance, r, which is estimated to be in the range of 4.39–5.37 nm. The binding free energy (?G) in each case remains effectively the same for each site because of enthalpy–entropy compensation (EEC). The difference observed between ?Cpexp and ?Cpcalc are suggested to be caused by binding–induced flexibility changes in the HSA. Efforts are also made to elaborate the differences observed in binding isotherms obtained through multiple approaches of calorimetry, spectroscopy and bioinformatics. We suggest that difference in dissociation constants of pollutants by calorimetry, spectroscopic and computational approaches could correspond to occurrence of different set of populations of pollutants having different molecular characteristics in ground state and excited state. Furthermore, our observation of enhanced binding of pollutants (2N and 8H) in the presence of hemin signifies that ligands like hemin may enhance the storage period of these pollutants in blood that may even facilitate the ill effects of these pollutants. PMID:22073150

Ahmad, Ejaz; Rabbani, Gulam; Zaidi, Nida; Singh, Saurabh; Rehan, Mohd; Khan, Mohd Moin; Rahman, Shah Kamranur; Quadri, Zainuddin; Shadab, Mohd.; Ashraf, Mohd Tashfeen; Subbarao, Naidu; Bhat, Rajiv; Khan, Rizwan Hasan

2011-01-01

337

Piezoelectric resonance calorimetry of nonlinear-optical crystals under laser irradiation  

NASA Astrophysics Data System (ADS)

Novel method is proposed for determination of nonlinear-optical crystal both heat transfer and optical absorption coefficients by measuring kinetics of the laser-irradiated crystal temperature-dependent piezoelectric resonance frequency. When laser radiation propagates through the crystal its temperature evaluation with time is directly determined from crystal piezoelectric resonance frequency shift, which is precisely measured by analyzing crystal response to the applied ac electric voltage. Heat transfer and optical absorption coefficients are obtained using measured characteristic time of crystal laser heating kinetics by solving nonstationary heat conduction equation. Experiments were performed with nonlinear-optical ?-quartz, lithium triborate (LBO) and periodically poled lithium niobate (PPLN) crystals.

Ryabushkin, Oleg A.; Konyashkin, Aleksey V.; Myasnikov, Daniil V.; Tyrtyshnyy, Valentin A.; Vershinin, Oleg I.

2013-09-01

338

VOL. 167 -NO. 12 HEATS OF EXCHANGE MEASURED BY FLOW CALORIMETRY 777 kaolinitic soil clay that he derived from the tem-  

E-print Network

#12;#12;#12;#12;VOL. 167 -NO. 12 HEATS OF EXCHANGE MEASURED BY FLOW CALORIMETRY 777 kaolinitic soil any reported values for K/Ca exchange. After look- ing at Udo's data more carefully,however, we be,-', not the 54.5 kJ mol,-' orig- inallyreported. If our calculation is correct,Udo's enthalpy for K/Ca exchange

Ma, Lena

339

Collider Physics: SDC/SSC liquified fiber calorimetry. [Physics Dept. , Texas A M Univ  

SciTech Connect

Most effort was directed toward the D-Zero experiment at Fermilab. Over 3 pb[sup [minus]1] of high-quality physics data have been obtained. Analysis of the results (wino-zino physics, squark physics), D-zero data acquisition systems efforts, and level-1 and level-2 trigger work are described. Other work concerned detector development for use at the SSC. This technology consists of using liquid scintillator-filled tubes as scintillating fibers for a calorimeter.'' The key issues were to demonstrate that the liquid fibers were sufficiently rad-hard and to demonstrate that fibers with sufficiently long attenuation length could be found to satisfy the resolution requirements; both constraints could be satisfied.

White, J.T.; Huson, F.R.

1992-01-01

340

Collider Physics: SDC/SSC liquified fiber calorimetry. Progress report, 1992  

SciTech Connect

Most effort was directed toward the D-Zero experiment at Fermilab. Over 3 pb{sup {minus}1} of high-quality physics data have been obtained. Analysis of the results (wino-zino physics, squark physics), D-zero data acquisition systems efforts, and level-1 and level-2 trigger work are described. Other work concerned detector development for use at the SSC. This technology consists of using liquid scintillator-filled tubes as scintillating fibers for a ``calorimeter.`` The key issues were to demonstrate that the liquid fibers were sufficiently rad-hard and to demonstrate that fibers with sufficiently long attenuation length could be found to satisfy the resolution requirements; both constraints could be satisfied.

White, J.T.; Huson, F.R.

1992-12-31

341

5/29/09 6:33 PMGlobal Warming and Cyclones: a Vicious Cycle? : Discovery News Page 1 of 3http://dsc.discovery.com/news/2009/05/14/tropical-cyclones-warming-print.html  

E-print Network

5/29/09 6:33 PMGlobal Warming and Cyclones: a Vicious Cycle? : Discovery News Page 1 of 3http://dsc.discovery.com/news/2009/05/14/tropical-cyclones-warming-print.html Discovery Channel « back Global Warming and Tropical Cyclones: a Vicious Cycle? Emily Sohn, Discovery News May 14, 2009 -- Global warming can change storm

Romps, David M.

342

Initial results of a silicon sensor irradiation study for ILC extreme forward calorimetry  

NASA Astrophysics Data System (ADS)

Detectors proposed for the International Linear Collider (ILC) incorporate a tungsten sampling calorimeter ('BeamCal') intended to reconstruct showers of electrons, positrons and photons that emerge from the interaction point of the collider with angles between 5 and 50 milliradians. For the innermost radius of this calorimeter, radiation doses at shower-max are expected to reach 100 MRad per year, primarily due to minimum-ionizing electrons and positrons that arise in the induced electromagnetic showers of e+e- 'beamstrahlung' pairs produced in the ILC beam-beam interaction. However, radiation damage to calorimeter sensors may be dominated by hadrons induced by nuclear interactions of shower photons, which are much more likely to contribute to the non-ionizing energy loss that has been observed to damage sensors exposed to hadronic radiation. We report here on the results of SLAC Experiment T-506, for which several different types of silicon diode sensors were exposed to doses of radiation induced by showering electrons of energy 3.5-10.6 GeV. By embedding the sensor under irradiation within a tungsten radiator, the exposure incorporated hadronic species that would potentially contribute to the degradation of a sensor mounted in a precision sampling calorimeter. Depending on sensor technology, efficient charge collection was observed for doses as large as 220 MRad.

Band, Reyer; Fadeyev, Vitaliy; Field, R. Clive; Key, Spencer; Kim, Tae Sung; Markiewicz, Thomas; Martinez-McKinney, Forest; Maruyama, Takashi; Mistry, Khilesh; Nidumolu, Ravi; Schumm, Bruce A.; Spencer, Edwin; Timlin, Conor; Wilder, Max

2014-11-01

343

Evaluating the Feasibility of an Agglomerative Hierarchy Clustering Algorithm for the Automatic Detection of the Arterial Input Function Using DSC-MRI  

PubMed Central

During dynamic susceptibility contrast-magnetic resonance imaging (DSC-MRI), it has been demonstrated that the arterial input function (AIF) can be obtained using fuzzy c-means (FCM) and k-means clustering methods. However, due to the dependence on the initial centers of clusters, both clustering methods have poor reproducibility between the calculation and recalculation steps. To address this problem, the present study developed an alternative clustering technique based on the agglomerative hierarchy (AH) method for AIF determination. The performance of AH method was evaluated using simulated data and clinical data based on comparisons with the two previously demonstrated clustering-based methods in terms of the detection accuracy, calculation reproducibility, and computational complexity. The statistical analysis demonstrated that, at the cost of a significantly longer execution time, AH method obtained AIFs more in line with the expected AIF, and it was perfectly reproducible at different time points. In our opinion, the disadvantage of AH method in terms of the execution time can be alleviated by introducing a professional high-performance workstation. The findings of this study support the feasibility of using AH clustering method for detecting the AIF automatically. PMID:24932638

Yin, Jiandong; Yang, Jiawen; Guo, Qiyong

2014-01-01

344

Absolute, soft x-ray calorimetry on the Z facility at Sandia National Laboratories  

SciTech Connect

Simple and reliable x-ray fluence measurements, in addition to time-resolved diagnostics, are needed to understand the physics of hot Z-pinch plasmas. A commercially available laser calorimeter has been modified for measuring soft x-ray fluence from the Z facility at Sandia National Laboratories. The x-ray absorber of this calorimeter is an aluminum disk, attached to a two-dimensional thermopile and surrounded by an isoperibol shroud. The time-integral and the maximum of the thermopile voltage signal are both proportional to the x-ray energy deposited. Data are collected for 90 seconds, and the instrument has, thus far, been used in the 1--25 mJ range. A wider dynamic measuring range for x-ray fluence (energy/area) can be achieved by varying the area of the defining aperture. The calorimeter is calibrated by an electrical substitution method. Calibrations are performed before and after each x-ray experiment on the Z facility. The calibration of the time-integral of the thermopile voltage vs. energy deposited (or the peak of thermopile voltage vs. energy deposited) is linear with zero offset at the 95% confidence level. The irreproducibility of the calibration is <2%, and the imprecision in the measurement of the incident x-ray energy (inferred from signal noise and the calibration) is estimated to be {approximately}0.9 mJ (95% confidence level). The inaccuracy is estimated at {+-}10%, due to correctable systematic errors (e.g., baseline shifts). Comparisons have been made of the calorimeter to time-resolved x-ray diagnostics, e.g., bolometers and XRD (x-ray diode) arrays, by integrating the flux measured by these instruments over time.

Fehl, D.L.; Muron, D.J.; Leeper, R.J.; Chandler, G.A.; Deeney, C.; Spielman, R.B.

1998-05-01

345

Defining a stem length-dependent binding mechanism for the cocaine-binding aptamer. A combined NMR and calorimetry study.  

PubMed

We have used a combined approach of NMR spectroscopy and isothermal titration calorimetry (ITC) to determine the ligand-binding mechanism employed by a cocaine-binding aptamer. We found that the length of the stem containing the 3' and 5' termini determines the nature of the binding mechanism. When this stem is six base pairs long, the secondary structure of the aptamer is fully folded in the free form and only putative tertiary interactions form with ligand binding. If this stem is shortened by three base pairs, the free form of the aptamer contains little secondary structure, and ligand binding triggers secondary structure formation and folding. This binding mechanism is supported by both NMR spectral changes and the ITC measured heat capacity of binding (?C(p)°). For the aptamer with the long stem the ?C(p)° value is -557 ± 29 cal mol(-1) K(-1) and for the aptamer with the short stem the ?C(p)° value is -922 ± 51 cal mol(-1) K(-1). Chemical shift perturbation data and the observation of intermolecular NOEs indicate that the three-way junction is the site of ligand binding. PMID:20735071

Neves, Miguel A D; Reinstein, Oren; Johnson, Philip E

2010-10-01

346

Characterization of Streptococcus pneumoniae thymidylate kinase: steady-state kinetics of the forward reaction and isothermal titration calorimetry.  

PubMed Central

Thymidylate kinase (TMK) catalyses the phosphorylation of dTMP to form dTDP in both the de novo and salvage pathways of dTTP synthesis. The tmk gene from the bacterial pathogen Streptococcus pneumoniae was identified. The gene, encoding a 212-amino-acid polypeptide (23352 Da), was cloned and overexpressed in Escherichia coli with an N-terminal hexahistidine tag. The enzyme was purified to homogeneity, and characterized in the forward reaction. The pH profile of TMK indicates that its activity is optimal at pH 8.5. The substrate specificity of the enzyme was examined; it was found that not only ATP, but also dATP and to a lesser extent CTP, could act as phosphate donors, and dTMP and dUMP could serve as phosphate acceptors. Furthermore, AZT-MP (3'-azido-3'-deoxythymidine 5'-monophosphate) was shown not to be a substrate for S. pneumoniae TMK. Steady-state kinetics and inhibition studies with adenosine 5'-[beta-thio]diphosphate and dTDP in addition to isothermal titration calorimetry were performed. The data showed that binding follows an ordered pathway, in which ATP binds first with a K(m) of 235 +/- 46 microM and a K(d) of 116 +/- 3 microM, and dTMP binds secondly with a K(m) of 66 +/- 12 microM and a K(d) of 53 +/- 2 microM. PMID:11964185

Petit, Chantal M; Koretke, Kristin K

2002-01-01

347

Interaction of ethylene oxide-propylene oxide copolymers with ionic surfactants studied by calorimetry: random versus block copolymers.  

PubMed

The present study used calorimetric techniques to follow the interaction of random and block ethylene oxide (EO)-propylene oxide (PO) copolymers with ionic surfactants. Features such as the intensity of the interaction (evaluated through their critical aggregation concentrations) and the profile of the isothermal titration calorimetry (ITC) curves were comparatively analyzed for random and block copolymers with similar composition (number of EO and PO units). Random copolymers displayed an interaction similar to that observed with other hydrophilic homopolymers with the additional characteristic that the intensity of the interaction increased with the increase in the copolymer hydrophobicity (as determined by its PO content), revealing that these copolymers display an intermediate behavior between PEO and PPO. For nonaggregated block copolymers (unimers) with large enough EO blocks (molar mass above 2000 g mol-1), ITC curves revealed that the anionic surfactant sodium dodecylsulfate (SDS) interacts with the PO and EO blocks almost independently, being more favorable with the PO block, which controls the critical aggregation concentration (cac) value. Effects of temperature and of the nature of the ionic surfactants on their interaction with these copolymers were found to agree with the previously reported trends. PMID:18081338

Niemiec, Anna; Loh, Watson

2008-01-24

348

Molecular dynamics of the supercooled pharmaceutical agent posaconazole studied via differential scanning calorimetry and dielectric and mechanical spectroscopies.  

PubMed

This paper presents comprehensive studies on the molecular dynamics of a pharmaceutically important substance, posaconazole. In order to characterize relaxation dynamics in the supercooled liquid and glassy states, dielectric and mechanical spectroscopies were applied. Dielectric data have indicated multiple relaxation processes that appear above and below the glass transition temperature Tg (??=100 s) of posaconazole. From the curvature of the dielectric log10(??) versus inverse of temperature dependence, we determine so-called "fragility", being a very popular parameter for classifying the structural dynamics of supercooled liquids and polymers. From the calculations, we get m=150, which means that is one of the most fragile glass-forming liquids. In this paper, the relaxation dynamics of supercooled posaconazole extracted from the dielectric response function was also confronted with shear-mechanical relaxation. Finally, we have also presented a direct comparison of the fragility and the number of dynamically correlated molecules Nc determined from dynamic calorimetry curves and dielectric and mechanical spectroscopies, showing a clear deviation in the picture of glass-transition dynamics generated by calorimetric and spectroscopic techniques. PMID:24010649

Adrjanowicz, K; Kaminski, K; Wlodarczyk, P; Grzybowska, K; Tarnacka, M; Zakowiecki, D; Garbacz, G; Paluch, M; Jurga, S

2013-10-01

349

Study of thermal properties and heat-induced denaturation and aggregation of soy proteins by modulated differential scanning calorimetry.  

PubMed

The thermal properties and heat-induced denaturation and aggregation of soy protein isolates (SPI) were studied using modulated differential scanning calorimetry (MDSC). Reversible and non-reversible heat flow signals were separated from the total heat flow signals in the thermograms. In the non-reversible profiles, two major endothermic peaks (at around 100 and 220 degrees C, respectively) associated with the loss of residual water were identified. In the reversible profiles, an exothermic peak associated with thermal aggregation was observed. Soy proteins denatured to various extents by heat treatments showed different non-reversible and reversible heat flow patterns, especially the exothermic peak. The endothermic or exothermic transition characteristics in both non-reversible and reversible signals were affected by the thermal history of the samples. The enthalpy change of the exothermic (aggregation) peak increased almost linearly with increase in relative humidity (RH) in the range between 8 and 85%. In contrast, the onset temperature of the exotherm decreased progressively with increase in RH. These results suggest that the MDSC technique could be used to study thermal properties and heat-induced denaturation/aggregation of soy proteins at low moisture contents. Associated functional properties such as water holding and hydration property can also be evaluated. PMID:16875727

Tang, Chuan-He; Choi, Siu-Mei; Ma, Ching-Yung

2007-01-30

350

An explicit formulation approach for the analysis of calcium binding to EF-hand proteins using isothermal titration calorimetry.  

PubMed

We present an improved and extended version of a recently proposed mathematical approach for modeling isotherms of ligand-to-macromolecule binding from isothermal titration calorimetry. Our approach uses ordinary differential equations, solved implicitly and numerically as initial value problems, to provide a quantitative description of the fraction bound of each competing member of a complex mixture of macromolecules from the basis of general binding polynomials. This approach greatly simplifies the formulation of complex binding models. In addition to our generalized, model-free approach, we have introduced a mathematical treatment for the case where ligand is present before the onset of the titration, essential for data analysis when complete removal of the binding partner may disrupt the structural and functional characteristics of the macromolecule. Demonstration programs playable on a freely available software platform are provided. Our method is experimentally validated with classic calcium (Ca(2+)) ion-selective potentiometry and isotherms of Ca(2+) binding to a mixture of chelators with and without residual ligand present in the reaction vessel. Finally, we simulate and compare experimental data fits for the binding isotherms of Ca(2+) binding to its canonical binding site (EF-hand domain) of polycystin 2, a Ca(2+)-dependent channel with relevance to polycystic kidney disease. PMID:24359756

Keeler, Camille; Poon, Gregory; Kuo, Ivana Y; Ehrlich, Barbara E; Hodsdon, Michael E

2013-12-17

351

Glossoscolex paulistus extracellular hemoglobin (HbGp) oligomeric dissociation upon interaction with sodium dodecyl sulfate: Isothermal titration calorimetry (ITC).  

PubMed

Annelid erythrocruorins are respiratory proteins with high cooperativity and low autoxidation rates. The giant extracellular hemoglobin of the earthworm, Glossoscolex paulistus (HbGp), has a molecular mass of 3.6 MDa. In this work, isothermal titration calorimetry (ITC), together with DLS and fluorescence emission have been used to investigate the interaction of SDS with the HbGp in the oxy-form, at pH 7.0. Our ITC and DLS results show that addition of SDS induces oxy-HbGp oligomeric dissociation, while a small amount of protein aggregation is observed only by DLS. Moreover, the oligomeric dissociation process is favored at lower protein concentrations. The temperature effect does not influence significantly the interaction of SDS with the hemoglobin, due to the similarities presented by the critical aggregation concentration (cac) and critical micelle concentration (cmc') for the mixtures. The increase of oxy-HbGp concentration leads to a slight variation of the cac values for the SDS-oxy-HbGp mixture, attributed mainly to the noncooperative electrostatic binding of surfactant to protein. However, the cmc' values increase considerably, associated to a more cooperative hydrophobic binding. Complementary pyrene fluorescence emission studies show formation of pre-micellar structures of the mixture already at lower SDS concentrations. This study opens the possibility of the evaluation of the surfactant effect on the hemoglobin stability by ITC, which is made for the first time with this extracellular hemoglobin. © 2014 Wiley Periodicals, Inc. Biopolymers 101: 1065-1076, 2014. PMID:24839186

Alves, Fernanda Rosa; Carvalho, Francisco Adriano O; Carvalho, José Wilson P; Tabak, Marcel

2014-10-01

352

Determination of fungal activity in modified wood by means of micro-calorimetry and determination of total esterase activity.  

PubMed

Beech and pine wood blocks were treated with 1,3-dimethylol-4,5-dihydroxyethylen urea (DMDHEU) to increasing weight percent gains (WPG). The resistance of the treated specimens against Trametes versicolor and Coniophora puteana, determined as mass loss, increased with increasing WPG of DMDHEU. Metabolic activity of the fungi in the wood blocks was assessed as total esterase activity (TEA) based on the hydrolysis of fluorescein diacetate and as heat or energy production determined by isothermal micro-calorimetry. Both methods revealed that the fungal activity was related with the WPG and the mass loss caused by the fungi. Still, fungal activity was detected even in wood blocks of the highest WPG and showed that the treatment was not toxic to the fungi. Energy production showed a higher consistency with the mass loss after decay than TEA; higher mass loss was more stringently reflected by higher heat production rate. Heat production did not proceed linearly, possibly due to the inhibition of fungal activity by an excess of carbon dioxide. PMID:18542949

Verma, Pradeep; Dyckmans, Jens; Militz, Holger; Mai, Carsten

2008-08-01

353

An Explicit Formulation Approach for the Analysis of Calcium Binding to EF-Hand Proteins Using Isothermal Titration Calorimetry  

PubMed Central

We present an improved and extended version of a recently proposed mathematical approach for modeling isotherms of ligand-to-macromolecule binding from isothermal titration calorimetry. Our approach uses ordinary differential equations, solved implicitly and numerically as initial value problems, to provide a quantitative description of the fraction bound of each competing member of a complex mixture of macromolecules from the basis of general binding polynomials. This approach greatly simplifies the formulation of complex binding models. In addition to our generalized, model-free approach, we have introduced a mathematical treatment for the case where ligand is present before the onset of the titration, essential for data analysis when complete removal of the binding partner may disrupt the structural and functional characteristics of the macromolecule. Demonstration programs playable on a freely available software platform are provided. Our method is experimentally validated with classic calcium (Ca2+) ion-selective potentiometry and isotherms of Ca2+ binding to a mixture of chelators with and without residual ligand present in the reaction vessel. Finally, we simulate and compare experimental data fits for the binding isotherms of Ca2+ binding to its canonical binding site (EF-hand domain) of polycystin 2, a Ca2+-dependent channel with relevance to polycystic kidney disease. PMID:24359756

Keeler, Camille; Poon, Gregory; Kuo, Ivana Y.; Ehrlich, Barbara E.; Hodsdon, Michael E.

2013-01-01

354

Enthalpy Changes during Photosynthetic Water Oxidation Tracked by Time-Resolved Calorimetry Using a Photothermal Beam Deflection Technique???  

PubMed Central

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, ?H, 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 ?V 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 ?H(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 ?V of about +42 Å3) may reflect O2 and proton release from the manganese complex, but also reorganization of the protein matrix. PMID:17993488

Krivanek, Roland; Dau, Holger; Haumann, Michael

2008-01-01

355

Interactions of poly(amidoamine) dendrimers with the surfactants SDS, DTAB, and C12EO6: an equilibrium and structural study using a SDS selective electrode, isothermal titration calorimetry, and small angle neutron scattering.  

PubMed

Interactions in aqueous solutions of different generations of poly(amidoamine) (PAMAM) dendrimers containing amine, hydroxyl, or delta-glucolactone functional groups at the periphery with the anionic surfactant sodium dodecyl sulfate (SDS) were investigated. We used a SDS-specific electrode (EMF) for SDS monomer concentration monitoring, isothermal titration calorimetry (ITC) for binding information, and small angle neutron scattering (SANS) for structural studies. ITC experiments monitoring the interaction of the dendrimers with cationic dodecyltrimethylammonium bromide (DTAB) and nonionic hexaethylene glycol mono-n-dodecyl ether (C12EO6) showed no significant binding effects. In contrast, SDS binds to all of the above dendrimers. EMF and ITC data demonstrated a regular trend for both the onset of binding and binding saturation as the generation in each family of dendrimers increased. In addition, generation G6 exhibited a noncooperative binding process at very low SDS concentrations. Furthermore, the onset of cooperative binding in the EMF experiments started at lower concentrations as the weight % (w/v), the size, and the numbers of the internal or surface groups increased. On the other hand, the binding capacity of the dendrimers showed only a small dependence on the above parameters. At SDS concentrations approaching the binding limit and also at selective concentrations within the binding range, SANS measurements indicated that in all cases the bound surfactant is in the micellar form. From the electromotive force (EMF) measurements, ITC data, and SANS data, the stoichiometry of the supramolecular complexes was determined. PMID:15461524

Sidhu, J; Bloor, The Late D M; Couderc-Azouani, S; Penfold, J; Holzwarth, J F; Wyn-Jones, E

2004-10-12

356

Thermodynamic investigations of ternary liquid alloys.  

PubMed

A review of different methods for determining thermodynamic quantities is given. The electromotive force (EMF) method with a liquid and solid electrolyte, the calorimetric and differential scanning calorimetry (DSC) methods, and vapour pressure experiments like the isopiestic and Knudsen effusion methods are discussed. PMID:21694202

Mikula, A; Knott, S

2008-03-19

357

A D.S.C study of the transformation of retained {beta} ({beta}{sub m}) obtained by quenching of Ti6Al4V  

SciTech Connect

{alpha} + {beta} titanium alloys are the most popular ones and therefore there is much information on phase transformation and mechanical properties for these alloys. Ti6Al4V belong to this group because of the Al and V additions. The vanadium stabilizes the {beta} (b.c.c.) phase of titanium and the aluminum stabilizes the {alpha} (h.c.p.) phase so that at low temperature it is possible to have in equilibrium a vanadium rich {beta} phase and an aluminum rich {alpha} phase. It is well known that {beta}-Ti6Al4V transforms into a h.c.p. martensitic phase {alpha}{prime} by rapid cooling from above the {beta} transus, for example by water quenching of not too thick samples. This transformation has no hardening effect for the alloy, however this {alpha}{prime} phase has very low ductility. In order to obtain better mechanical characteristics a lot of work has been performed on thermal and thermomechanical treatments. It was observed that the {beta} phase when water quenched from temperatures below the {beta} transus does not transform completely into {alpha}{prime} leaving retained {beta}, named {beta}{sub m}, at room temperature. This {beta}{sub m} phase is in a metastable condition and can transform to {alpha}{prime} if activated. There is no calorimetric analysis for this {beta}{sub m} {yields} {alpha}{prime} transition, the thermal effect being certainly very low as for all the processes which may be mechanically activated. In the authors` work they use the sensitive D.S.C. technique for the calorimetric investigation of the transformation {beta}{sub m} {yields} {alpha}{prime} up to 600 C. They determine also the optimal temperature range from which {beta}{sub m} may be obtained by water quenching of the alloy and they correlate the results with other previously published partial ones.

Mekideche, A.; Debuigne, J. [INSA, Rennes (France). Laboratoire de Metallurgie et Physico-Chimie des Materiaux] [INSA, Rennes (France). Laboratoire de Metallurgie et Physico-Chimie des Materiaux; Matecki, M. [Univ. de Rennes 1 (France)] [Univ. de Rennes 1 (France)

1996-05-01

358

Substituent control of DNA binding modes in a series of chalcogenoxanthylium photosensitizers as determined by isothermal titration calorimetry and topoisomerase I DNA unwinding assay  

Microsoft Academic Search

The DNA binding efficacy and preferred mode of binding of a series of rhodamine-related chalcogenoxanthylium dyes was investigated by isothermal titration calorimetry (ITC) using ctDNA, [poly(dCdG)]2 and [poly(dAdT)]2, and by a topoisomerase I DNA unwinding (Topo I) assay. The dyes of this study showed tight binding to ctDNA with binding constants, Kb, on the order of 106–107M?1. The ITC and

Ruel E. McKnight; Bilgehan Onogul; Shivani R. Polasani; Michael K. Gannon II; Michael R. Detty

2008-01-01

359

Avalanche correlations in the martensitic transition of a Cu-Zn-Al shape memory alloy: analysis of acoustic emission and calorimetry.  

PubMed

The existence of temporal correlations during the intermittent dynamics of a thermally driven structural phase transition is studied in a Cu-Zn-Al alloy. The sequence of avalanches is observed by means of two techniques: acoustic emission and high sensitivity calorimetry. Both methods reveal the existence of event clustering in a way that is equivalent to the Omori correlations between aftershocks in earthquakes as are commonly used in seismology. PMID:24599153

Baró, Jordi; Martín-Olalla, José-María; Romero, Francisco Javier; Gallardo, María Carmen; Salje, Ekhard K H; Vives, Eduard; Planes, Antoni

2014-03-26

360

Dietary effects on resting metabolic rate in C57BL/6 mice are differentially detected by indirect (O2/CO2 respirometry) and direct calorimetry  

PubMed Central

Resting metabolic rate (RMR) studies frequently involve genetically-manipulated mice and high fat diets (HFD). We hypothesize that the use of inadequate methods impedes the identification of novel regulators of RMR. This idea was tested by simultaneously measuring RMR by direct calorimetry and respirometry in C57BL/6J mice fed chow, 45% HFD, and then returned to chow. Comparing results during chow feeding uncovered an underestimation of RMR by respirometry (0.010 ± 0.001 kcal/h, P < 0.05), which is equivalent in magnitude to ?2% of total daily caloric turnover. RMR during 45% HFD feeding was increased by respirometry (+0.013 ± 0.003 kcal/h, P < 0.05), but not direct calorimetry (+0.001 ± 0.002 kcal/h). Both methods indicated that return to chow reduced RMR compared to HFD, though direct calorimetry indicated a reduction below the initial chow fed state (?0.019 ± 0.004 kcal/h versus baseline, P < 0.05) that was not detected by respirometry (?0.003 ± 0.002 kcal/h versus baseline). These results highlight method-specific interpretations of the effects of dietary interventions upon RMR in mice, and prompt the reevaluation of preclinical screening methods used to identify novel RMR modulators. PMID:24944905

Burnett, Colin M.L.; Grobe, Justin L.

2014-01-01

361

Versatile peroxidase degradation of humic substances: use of isothermal titration calorimetry to assess kinetics, and applications to industrial wastes.  

PubMed

The kinetic constants of a hybrid versatile-peroxidase (VP) which oxidizes complex polymeric humic substances (HS) derived from lignin (humic and fulvic acids) and industrial wastes were determined for the first time using isothermal titration calorimetry (iTC). The reaction conditions were manipulated to enable manganese-peroxidase (MnP) and/or lignin-peroxidase (LiP) activities to be evaluated. The peroxidase reactions exhibited varying degrees of product inhibition or activation; properties which have not previously been reported for VP enzymes. In contrast to previous work (Ertan et al., 2012) on small non-polymeric substrates (MnSO4, veratryl alcohol and dyes), all kinetic plots for polymeric HS were sigmoidal, lacked Michaelis-Menten characteristics, and were indicative of positive cooperativity. Under conditions when both LiP and MnP were active, the kinetic data fitted to a novel biphasic Hill Equation, and the rate of enzymatic reaction was significantly greater than the sum of individual LiP plus MnP activities implying synergistic activation. By employing size-exclusion chromatography and electrospray ionization mass spectrometry, the characteristics of the oxidative degradation products of the HS were also monitored. Our study showed that the allosteric behaviour of the VP enzyme promotes a high level of regulation of activity during the breakdown of model and industrial ligninolytic substrates. The work was extended to examine the kinetics of breakdown of industrial wastes (effluent from a pulp and paper plant, and fouled membrane solids extracted from a ground water treatment membrane) revealing unique, VP-mediated, kinetic responses. This work demonstrates that iTC can be successfully employed to study the kinetic properties of VP enzymes in order to devise reaction conditions optimized for oxidative degradation of HS present in materials used in a wide range of industries. PMID:24631722

Siddiqui, Khawar Sohail; Ertan, Haluk; Charlton, Timothy; Poljak, Anne; Daud Khaled, A K; Yang, Xuexia; Marshall, Gavin; Cavicchioli, Ricardo

2014-05-20

362

Photodegradation assessment of ciprofloxacin, moxifloxacin, norfloxacin and ofloxacin in the presence of excipients from tablets by UPLC-MS/MS and DSC  

PubMed Central

Background Ciprofloxacin (CIP), moxifloxacin (MOX), norfloxacin (NOR) and ofloxacin (OFL), are the antibacterial synthetic drugs, belonging to the fluoroquinolones group. Fluoroquinolones are compounds susceptible to photodegradation process, which may lead to reduction of their antibacterial activity and to induce phototoxicity as a side effect. This paper describes a simple, sensitive UPLC-MS/MS method for the determination of CIP, MOX, NOR and OFL in the presence of photodegradation products. Results Chromatographic separations were carried out using the Acquity UPLC BEH C18 column; (2.1?×?100 mm, 1.7 ?m particle size). The column was maintained at 40°C, and the following gradient was used: 0 min, 95% of eluent A and 5% of eluent B; 10 min, 0% of eluent A and 100% of eluent B, at a flow rate of 0.3 mL min-1. Eluent A: 0.1% (v/v) formic acid in water; eluent B: 0.1% (v/v) formic acid in acetonitrile. The method was validated and all the validation parameters were in the ranges acceptable by the guidelines for analytical method validation. The photodegradation of examined fluoroquinolones in solid phase in the presence of excipients followed kinetic of the first order reaction and depended upon the type of analyzed drugs and coexisting substances. Photodegradation process of analyzed drugs was confirmed by differential scanning calorimetry. In addition, the identification of degradation products was carried out by mass spectrometry. Conclusion The developed UPLC-MS/MS method enables the determination of CIP, MOX, NOR and OFL in the presence of photodegradation products and identification of photodegradation products. PMID:23899303

2013-01-01

363

Liquid scintillator sampling calorimetry  

E-print Network

were excellent, demonstrating for the first time that a device of this type was technically feasible and providing valuable information for future designs. The details of the design, construction, testing and analysis are provided....

Dudgeon, R. Greg

1994-01-01

364

Implementation of the Domino Sampling Waveform digitizer in the PIBETA experiment  

NASA Astrophysics Data System (ADS)

The Domino Sampling Chip(DSC)-Waveform digitization system is a significant addition to electronics arsenal of PIBETA experiment. It is used to digitize waveforms from every photo tube in the detector. Through carefully programmed offline analysis of its raw data collected during regular runtime, better timing and energy resolution are achieved compared with feast's results. And more importantly, the geometric character of the digitized waveform which contains information of energy deposition of particle decays can be utilized for particle identification, a great advantage that regular unit could not possess. In addition to fastbus, incorporate DSC data through its offline analysis including timing and energy offset, scale calibration will contribute a final more precise result of PIBETA experiment.

Wang, Ying

365

Archeomagnetic dating of the eruption of Xitle volcano (Mexico) from a reappraisal of the paleointensity with the MSP-DSC protocol.  

NASA Astrophysics Data System (ADS)

The Xitle volcano, located south of Mexico City, is a monogenic volcano that has provided seven lava flows in a time interval of a few years. The age of these eruptions, estimated by means of radiocarbon dates on charcoal from beneath the flows, is still very poorly known, ranging from 4765±90 BC to 520±200 AD (see Siebe, JVGR, 2000 for a review). This lava field was emplaced over the archaeological city of Cuicuilco whose occupation is estimated between 700 BC and 150 AD. Thus a question is still pending: Is the downfall of Cuicuilco directly attributable to the eruption of Xitle? It seems that the answer is negative if we consider the latest radiocarbon dating by Siebe (2000), which sets the age of the eruption to 280±35 AD, that is significantly younger to the abandon of the city. Because this new age has direct implications on the history of the movements of ancient populations in the Central Valley of Mexico, we propose in the present study to check this estimate by archaeomagnetic dating. Xitle lava have been investigated several times for paleomagnetism, including directional analyses and absolute paleointensity determinations (see Alva, EPS, 57, 839-853, 2005 for a review). The characteristic Remanence direction is precisely determined. It is much more difficult to estimate precisely the paleointensity with the Thellier method: values scatter between 40 and 90 ?T in a single flow (Alva, 2005). We propose here to estimate the paleointensity by means of the MSP-DSC protocol (Fabian and Leonhardt, 2010) with the new ultra-fast heating furnace FUReMAG developed in Montpellier (France). The sampling was performed along four profiles, one vertical through the entire thickness of the flow and three horizontal (at the top, middle and the bottom of the flow). Our preliminary results show that there is no difference between the values found in the different profiles, all providing a value around 62 ?T. The comparison of our results (Dec = 359.0°, Inc = 35.2°, F=62.8±1.1 ?T) with the model CALS3K.4 for secular variation provided an Archaeomagnetic age between 176 BC and 58 BC at 95% significance value. This age is consistent with the hypothesis of archaeological destruction and the abandonment of Cuicuilco during the eruption of the Xitle volcano.

Bravo-Ayala, Manuel; Camps, Pierre; Alva-Valdivia, Luis; Poidras, Thierry; Nicol, Patrick

2014-05-01

366

Oxide Melt Solution Calorimetry of Fe2+ -bearing Oxides and Application to the Magnetite - Maghemite (Fe3O4-Fe8/3O4) system  

SciTech Connect

A consistent methodology for obtaining enthalpy of formation of Fe{sup 2+}-containing binary and multicomponent oxides using high temperature oxide melt solution calorimetry has been developed. The enthalpies of wuestite (FeO) and magnetite (Fe{sub 3}O{sub 4}) oxidation to hematite (Fe{sub 2}O{sub 3}) were measured using oxidative drop solution calorimetry in which the final product is dissolved ferric oxide. Two methods were applied: drop solution calorimetry at 1073 K in lead borate solvent and at 973 K in sodium molybdate, each under both oxygen flowing over and bubbling through the solvent, giving consistent results in agreement with literature values. The enthalpies of formation of all three iron oxides from the elements were obtained using a thermodynamic cycle involving the directly measured oxidative dissolution enthalpy of iron metal in sodium molybdate at 973 K and gave excellent consistency with literature data. The methodology was then applied to the magnetite - maghemite system. The enthalpy of mixing of the Fe{sub 3}O{sub 4}-Fe{sub 8/3}O{sub 4} spinel solid solution is exothermic and, 2 represented by a subregular (Margules) formalism, {Delta}H{sub mix} = x(1-x)(-63.36 {+-} 8.60(1-x) + 17.65 {+-} 6.40x) kJ/mol, where x is the mole fraction of magnetite. The entropies of mixing of the solid solution were calculated for different assumptions about the distribution of cations, charges, and vacancies in these defect spinels. The different models lead to only small differences in the entropy of mixing. Calculated free energies of mixing show no evidence for a solvus in the magnetite - maghemite system.

Lilova, Kristina I.; Xu, Fen; Rosso, Kevin M.; Pearce, Carolyn I.; Kamali, Saeed; Navrotsky, Alexandra

2012-01-01

367

Hydration water and peptide dynamics--two sides of a coin. A neutron scattering and adiabatic calorimetry study at low hydration and cryogenic temperatures.  

PubMed

In the present work we bridge neutron scattering and calorimetry in the study of a low-hydration sample of a 15-residue hybrid peptide from cecropin and mellitin CA(1-7)M(2-9) of proven antimicrobial activity. Quasielastic and low-frequency inelastic neutron spectra were measured at defined hydration levels - a nominally 'dry' sample (specific residual hydration h = 0.060 g/g), a H2O-hydrated (h = 0.49) and a D2O-hydrated one (h = 0.51). Averaged mean square proton mobilities were derived over a large temperature range (50-300 K) and the vibrational density of states (VDOS) were evaluated for the hydrated samples. The heat capacity of the H2O-hydrated CA(1-7)M(2-9) peptide was measured by adiabatic calorimetry in the temperature range 5-300 K, for different hydration levels. The glass transition and water crystallization temperatures were derived in each case. The existence of different types of water was inferred and their amounts calculated. The heat capacities as obtained from direct calorimetric measurements were compared to the values derived from the neutron spectroscopy by way of integrating appropriately normalized VDOS functions. While there is remarkable agreement with respect to both temperature dependence and glass transition temperatures, the results also show that the VDOS derived part represents only a fraction of the total heat capacity obtained from calorimetry. Finally our results indicate that both hydration water and the peptide are involved in the experimentally observed transitions. PMID:23986181

Bastos, Margarida; Alves, Nuno; Maia, Sílvia; Gomes, Paula; Inaba, Akira; Miyazaki, Yuji; Zanotti, Jean-Marc

2013-10-21

368

Thermal phase behavior of 1-butyl-3-methylimidazolium hexafluorophosphate: Simultaneous measurements of the melting of two polymorphic crystals by Raman spectroscopy and calorimetry  

NASA Astrophysics Data System (ADS)

The thermal phase behavior of 1-butyl-3-methylimidazolium hexafluorophosphate, which forms three polymorphic crystals (?, ?, and ?), has been re-investigated by the simultaneous measurements of Raman spectroscopy and calorimetry. The peak assigned to the phase change from ? to ? phase is found to be exothermic and, in striking contrast with a previous report, the peak for this transition is observed near 255 K by recooling and subsequent reheating of the ? phase. This finding enabled separate measurements of the melting points (285.8 and 285.3 K), fusion enthalpies (13.1 and 22.6 kJ mol-1), and entropies of the ? and ? phases, respectively.

Endo, Takatsugu; Nishikawa, Keiko

2013-10-01

369

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  

PubMed Central

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. PMID:24069218

Casiraghi, Francesca; Chavez, Alberto O.; Davalli, Alberto M.; Naegelin, Terry; Comuzzie, Anthony G.; Frost, Patricia; Musi, Nicolas; Folli, Franco

2013-01-01

370

Absorbed dose to water determination with ionization chamber dosimetry and calorimetry in restricted neutron, photon, proton and heavy-ion radiation fields  

NASA Astrophysics Data System (ADS)

Absolute dose measurements with a transportable water calorimeter and ionization chambers were performed at a water depth of 20 mm in four different types of radiation fields, for a collimated 60Co photon beam, for a collimated neutron beam with a fluence-averaged mean energy of 5.25 MeV, for collimated proton beams with mean energies of 36 MeV and 182 MeV at the measuring position, and for a 12C ion beam in a scanned mode with an energy per atomic mass of 430 MeV u-1. The ionization chambers actually used were calibrated in units of air kerma in the photon reference field of the PTB and in units of absorbed dose to water for a Farmer-type chamber at GSI. The absorbed dose to water inferred from calorimetry was compared with the dose derived from ionometry by applying the radiation-field-dependent parameters. For neutrons, the quantities of the ICRU Report 45, for protons the quantities of the ICRU Report 59 and for the 12C ion beam, the recommended values of the International Atomic Energy Agency (IAEA) protocol (TRS 398) were applied. The mean values of the absolute absorbed dose to water obtained with these two independent methods agreed within the standard uncertainty (k = 1) of 1.8% for calorimetry and of 3.0% for ionometry for all types and energies of the radiation beams used in this comparison.

Brede, H. J.; Greif, K.-D.; Hecker, O.; Heeg, P.; Heese, J.; Jones, D. T. L.; Kluge, H.; Schardt, D.

2006-08-01

371

Direct calorimetry identifies deficiencies in respirometry for the determination of resting metabolic rate in C57Bl/6 and FVB mice  

PubMed Central

Substantial research efforts have been aimed at identifying novel targets to increase resting metabolic rate (RMR) as an adjunct approach to the treatment of obesity. Respirometry (one form of “indirect calorimetry”) is unquestionably the dominant technique used in the obesity research field to assess RMR in vivo, although this method relies upon a lengthy list of assumptions that are likely to be violated in pharmacologically or genetically manipulated animals. A “total” calorimeter, including a gradient layer direct calorimeter coupled to a conventional respirometer, was used to test the accuracy of respirometric-based estimations of RMR in laboratory mice (Mus musculus Linnaeus) of the C57Bl/6 and FVB background strains. Using this combined calorimeter, we determined that respirometry underestimates RMR of untreated 9- to 12-wk-old male mice by ?10–12%. Quantitative and qualitative differences resulted between methods for untreated C57Bl/6 and FVB mice, C57Bl/6 mice treated with ketamine-xylazine anesthesia, and FVB mice with genetic deletion of the angiotensin II type 2 receptor. We conclude that respirometric methods underestimate RMR in mice in a magnitude that is similar to or greater than the desired RMR effects of novel therapeutics. Sole reliance upon respirometry to assess RMR in mice may lead to false quantitative and qualitative conclusions regarding the effects of novel interventions. Increased use of direct calorimetry for the assessment of RMR and confirmation of respirometry results and the reexamination of previously discarded potential obesity therapeutics are warranted. PMID:23964071

Burnett, Colin M. L.

2013-01-01

372

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

SciTech Connect

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.

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

373

A new technique for determining charge and momentum of electrons and positrons using calorimetry and silicon tracking  

SciTech Connect

We describe the application of a new methods for the determination of charge and track parameters for electrons and positrons in both central (pseudo-rapidity 0 < |{eta}| < 1.2) and forward (pseudo- rapidity 1.2 < |{eta}| < 2.3) regions at CDF. The method uses the shower centroid position in the calorimeter in combination with a track in the inner silicon vertex detector. The use of the central tracking chamber is not required. A comparison of the shower centroid in the calorimeter, with the extrapolated silicon vertex detector track determines the electron sign. This technique has been used to measure the W asymmetry in CDF in regions beyond the pseudo-rapidity coverage of the central tracking chamber. Application to other Physics analyses in current collider experiments at the Tevatron and in future high luminosity experiments at the LHC are discussed. 5 refs., 5 figs., 1 tab.

Fan, Q.; Bodek, A. [Rochester Univ., NY (United States). Dept. of Physics and Astronomy]|[Fermi National Accelerator Lab., Batavia, IL (United States)

1996-12-01

374

Measurement of boundaries between two-phase and three-phase regions in emulsified systems by titration calorimetry; 2: Determination of phase compositions in three-phase systems  

SciTech Connect

It has been demonstrated that isoperibolic titration calorimetry can be used to determine the tie-triangles (i.e., compositions of conjugate top, middle, and bottom phases) of amphiphile/oil/water systems. Simple regressions to temperatures, heats, or their respective derivatives, measured as a function of system composition, gave multiple compositional points on each side of the tie-triangle. An equation for each side then was calculated from a regression to the respective set of compositional points. Finally, phase compositions were obtained by solving the equations for the respective sides of the tie-triangle for their three points of intersection. No dependence of the phase boundary points on the morphologies of the emulsions was found. Densities of 2-butoxyethanol from 24 to 50 C also are reported.

Smith, D.H.; Covatch, G.L. (Morgantown Energy Technology Center, WV (United States) Univ. of Oklahoma, Norman, OK (United States))

1994-02-01

375

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

PubMed Central

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 osteoarthritis (10 pre- and 10 post total hip arthroplasty; 40% female; age: 63.3?±?9.0; BMI: 23.7?±?3.7). All patients completed a 2 hour protocol of simulated free living with 8 different typical physical activity types. Energy consumption (kcal/min) was estimated by the Sense Wear pro3 Armband activity monitor and validated against indirect calorimetry (criterion method) by means of a portable unit (Cosmed K4b2). Bias and variance was analyzed using functional ANOVA. Results Mean bias during all activities was 1.5 Kcal/min 95%CI [1.3; 1.8] corresponding to 72% (overestimation). Normal gait speed showed an overestimation of 2.8 Kcal/min, 95%CI [2.3; 3.3] (93%) while an underestimation of -1.1 Kcal/min, 95%CI [-1.8; -0.3] (-25%) was recorded during stair climb. Activities dominated by upper body movements showed large overestimation with 4.37 Kcal/min, 95%CI [3.8; 5.1] (170%) being recorded during gardening. Both bias and variance appeared to be dependent on activity type. Conclusion The activity monitor generally overestimated the energy consumption during common activities of low to medium intensity in the patient group. The size and direction of the bias was highly dependent on the activity type which indicates the activity monitor is of limited value in patients with hip osteoarthritis and that the results do not express the real energy expenditure. PMID:24552503

2014-01-01

376

Experience matters 1 Experience matters  

E-print Network

of these theories best describes human information search. Experiment 1, which used natural sampling and experienceExperience matters 1 Experience matters: Information acquisition optimizes probability gain Jonathan D. Nelson Max Planck Institute for Human Development Craig R. M. McKenzie University of California

Nelson, Jonathan D.

377

MicroBooNE: A New Liquid Argon Time Projection Chamber Experiment  

SciTech Connect

Liquid Argon Time Projection Chamber detectors are well suited to study neutrino interactions, and are an intriguing option for future massive detectors capable of measuring the parameters that characterize neutrino oscillations. These detectors combine fine-grained tracking with calorimetry, allowing for excellent imaging and particle identification ability. In this talk the details of the MicroBooNE experiment, a 175 ton LArTPC which will be exposed to Fermilab's Booster Neutrino Beamline starting in 2011, will be presented. The ability of MicroBooNE to differentiate electrons from photons gives the experiment unique capabilities in low energy neutrino interaction measurements.

Soderberg, M.

2009-10-01

378

Affinity between TBC1D4 (AS160) phosphotyrosine-binding domain and insulin-regulated aminopeptidase cytoplasmic domain measured by isothermal titration calorimetry.  

PubMed

Uptake of circulating glucose into the cells happens via the insulin- mediated signalling pathway, which translocates the glucose transporter 4 (GLUT4) vesicles from the intracellular compartment to the plasma membrane. Rab?GTPases are involved in this vesicle trafficking, where Rab?GTPase-activating proteins (RabGAP) enhance the GTP to GDP hydrolysis. TBC1D4 (AS160) and TBC1D1 are functional RabGAPs in the adipocytes and the skeletonal myocytes, respectively. These proteins contain two phosphotyrosine-binding domains (PTBs) at the amino-terminus of the catalytic RabGAP domain. The second PTB has been shown to interact with the cytoplasmic region of the insulin-regulated aminopeptidase (IRAP) of the GLUT4 vesicle. In this study, we quantitatively measured the ??M affinity (KD) between TBC1D4 PTB and IRAP using isothermal titration calorimetry, and further showed that IRAP residues 1-49 are the major region mediating this interaction. We also demonstrated that the IRAP residues 1-15 are necessary but not sufficient for the PTB interaction. PMID:22732222

Park, SangYoun; Kim, Keon Young; Kim, Sunmin; Yu, Young Seok

2012-06-01

379

Enthalpies of formation of CaAl4O7 and CaAl12O19 (hibonite) by high temperature, alkali borate solution calorimetry  

NASA Technical Reports Server (NTRS)

Enthalpies of formation were determined for two calcium aluminate phases, CaAl4O7 and CaAl12O19, using high-temperature alkali borate solution calorimetry. The aluminates were synthesized by multiple-cycle heating and grinding stoichiometric mixtures of CaCO3 and Al2O3, and the products were characteized by X-ray diffraction and SEM microbeam analysis. The data on impurities (CaAl4O7 was found to be about 89.00 percent pure by weight and the CaAl12O19 samples about 91.48 percent pure) were used to correct the heat of solution values of the synthetic products. The enthalpies of formation, at 1063 K, from oxides, were found to be equal to -(25.6 + or - 4.7) kJ/g.f.w. for CaAl4O7 and -(33.0 + or - 9.7) kJ/g.f.w. for CaAl12O19; the respective standard enthalpies of formation from elements, at 298 K, were estimated to be -4007 + or - 5.2 kJ/g.f.w. and -10,722 + or - 12 kJ/g.f.w.

Geiger, C. A.; Kleppa, O. J.; Grossman, L.; Mysen, B. O.; Lattimer, J. M.

1988-01-01

380

Compressibility, isothermal titration calorimetry and dynamic light scattering analysis of the aggregation of the amphiphilic phenothiazine drug thioridazine hydrochloride in water/ethanol mixed solvent  

NASA Astrophysics Data System (ADS)

Thioridazine hydrochloride is a drug used in treatment of mental illness that shows side effects. Therefore, it is interesting to study the change of the physico-chemical properties of the drug in different environments to understand the mechanism of action of the drug. Thioridazine can be considered as a hydrotrope if we considered that the term comprise hydrophilic and hydrophobic moieties that form aggregates by a stacking mechanism as it is the case of all the phenothiazine tranquillizing drugs. The association properties of the amphiphilic phenothiazine drug thioridazine hydrochloride were investigated by density, ultrasound, isothermal titration calorimetry and dynamic light scattering (DLS), yielding values of the critical concentration, adiabatic apparent compressibilities and hydrodynamic radius. The DLS data were analyzed according to the treatment of the Derjaguin, Landau, Verwey and Overbeek (DLVO) theory to study the stability of the system. The aim of the study is to obtain information about the physico-chemical characterization of the drug in aqueous solution and the effect of ethanol on the aggregate stability of this amphiphilic drug. The phenothiazine tranquillizing drugs have interesting association characteristics that derive from their rigid, tricyclic hydrophobic groups.

Cheema, Mohammad Arif; Siddiq, Mohammad; Barbosa, Silvia; Castro, Emilio; Egea, José A.; Antelo, Luis T.; Taboada, Pablo; Mosquera, Víctor

2007-07-01

381

Energies of peptide peptide and peptide water hydrogen bonds in collagen: Evidences from infrared spectroscopy, quartz piezogravimetry and differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

The aim of the present work is a quantitative estimation of energies of peptide-peptide N 1sbnd H 1⋯O 2dbnd C 2 and peptide-water hydrogen bonds in collagen type I and model collagen polypeptide poly(Gly-Pro-Pro). Being a challenging theoretical task this is also an issue that can clarify the physical basis of stability of collagen structures that play a very important structural role in connective tissue. The study was performed on the basis of a complex approach of a number of experimental techniques, namely infrared spectroscopy, quartz piezogravimetry and differential scanning calorimetry. Our results indicate that binding of 3-4 water molecules of the internal hydration shell to each -Gly-X-Y- unit of poly(Gly-Pro-Pro) and collagen leads to simultaneous conformational reorganization of the triple helix and strengthening of the peptide-peptide hydrogen bonds. Enthalpies of hydration of poly(Gly-Pro-Pro) and collagen constitute -10.9 and -12.2 kJ/mol, respectively. Enthalpies of peptide-peptide N 1sbnd H 1⋯O 2dbnd C 2 hydrogen bonds are -7.6 and -6.0 kJ/mol in poly(Gly-Pro-Pro) and collagen, correspondently. The results obtained can be used for evaluation of the impacts of energies of different types of interactions into the total energy of stabilization of native triple helical collagen and poly(Gly-Pro-Pro).

Boryskina, O. P.; Bolbukh, T. V.; Semenov, M. A.; Gasan, A. I.; Maleev, V. Ya.

2007-02-01

382

Unraveling the impact of hydroxylation on interactions of bile acid cationic lipids with model membranes by in-depth calorimetry studies.  

PubMed

We used eight bile acid cationic lipids differing in the number of hydroxyl groups and performed in-depth differential scanning calorimetry studies on model membranes doped with different percentages of these cationic bile acids. These studies revealed that the number and positioning of free hydroxyl groups on bile acids modulate the phase transition and co-operativity of membranes. Lithocholic acid based cationic lipids having no free hydroxyl groups gel well with dipalmitoylphosphatidylcholine (DPPC) membranes. Chenodeoxycholic acid lipids having one free hydroxyl group at the 7'-carbon position disrupt the membranes and lower their co-operativity. Deoxycholic acid and cholic acid based cationic lipids have free hydroxyl groups at the 12'-carbon position, and at 7'- and 12'-carbon positions respectively. Doping of these lipids at high concentrations increases the co-operativity of membranes suggesting that these lipids might induce self-assembly in DPPC membranes. These different modes of interactions between cationic lipids and model membranes would help in future for exploring their use in DNA/drug delivery. PMID:25098317

Singh, Manish; Bajaj, Avinash

2014-09-28

383

Interaction of arginine with protein during refolding process probed by amide H/D exchange mass spectrometry and isothermal titration calorimetry.  

PubMed

Arginine has been widely used as low molecular weight additive to promote protein refolding by suppressing aggregate formation. However, methods to investigate the role of arginine in protein refolding are often limited on protein's global conformational properties. Here, hydrogen/deuterium exchange mass spectrometry (HDX-MS) was used to study the effects of arginine on recombinant human granulocyte colony-stimulating factor (rhG-CSF) refolding at the scale of peptide mapping. It was found that deuteration levels of rhG-CSF refolded with arginine was higher than that without arginine during the whole refolding process, but they became almost the same when the refolding reached equilibrium. This phenomenon indicated that arginine could protect some amide deuterium atoms from being exchanged with hydrogen, but the protection diminished gradually along with refolding proceeding. Enzymatic digestion revealed six particular peptides of 16-47, 72-84, 84-93, 114-124, 145-153 and 154-162 were mainly responsible for the deuteration, and all of them dominantly located in protein's ?-helix domain. Furthermore, thermodynamics analysis by isothermal titration calorimetry provided direct evidence that arginine could only react with denatured and partially refolded rhG-CSF. Taking all of the results together, we suggest that arginine suppresses protein aggregation by a reversible combination. At the initial refolding stage, arginine could combine with the denatured protein mainly through hydrogen bonding. Subsequently, arginine is gradually excluded from protein with protein's native conformation recovering. PMID:25461798

Zhao, Dawei; Liu, Yongdong; Zhang, Guifeng; Zhang, Chun; Li, Xiunan; Wang, Qingqing; Shi, Hong; Su, Zhiguo

2015-01-01

384

Weather Experiments  

NSDL National Science Digital Library

Looking for fun ways to learn about weather? Weather Wiz Kids has 39 fun weather related experiments for you to try. These experiments can be done in the classroom with your friends or even at home! Some of the experiments on the site include: tornado in a bottle, make lightning, make it rain, cloud in a bottle, what's in the wind, the Doppler Effect, and baking soda volcano.

2010-01-01

385

Translating experience  

Microsoft Academic Search

This paper describes research investigating the significance of physical experience and materiality in creative digital visual art and design practice. Findings are presented from a recent phenomenological study, which indicates the ways in which memory of lived experience informs creative cognition and feeds the imagination.The importance of physical engagement with the world, through the senses, enables emotional expression to be

Cathy Treadaway

2009-01-01

386

Herschel Experiment  

NSDL National Science Digital Library

In this experiment, students replicate a version of the 1800 experiment in which a form of radiation other than visible light was discovered by the famous astronomer Sir Frederick William Herschel. Students use glass prisms, thermometers, and sunlight to detect the increase in temperature beyond the red end of the visible spectrum, thus detecting infrared light.

387

Thermoelectrical and thermal analyses of copper(II) acetate monohydrate ZnO–matrix composite powder obtained by freeze-drying  

Microsoft Academic Search

The thermal history of freeze-dried mixtures of composite powders containing ZnO–matrix and (CH3COO)2Cu·H2O (copper(II) acetate monohydrate) was undertaken by thermal analysis (TA) coupled to thermoelectrical analysis (TEA). Experiments were carried out on compacted samples, under non-isothermal conditions, in air, up to 350°C, by measuring the electrical resistance during heating, called thermoelectrical resistometry (TER), and by differential scanning calorimetry (DSC). Activation

Jusmar Valentin Bellini; Edgardo Alfonso Gomez Pineda; Raquel de Almeida Rocha; Andre Luis de Lima Ponzoni; Andrea Paesano Jr.

2006-01-01

388

TRIO experiment  

SciTech Connect

The TRIO experiment is a test of in-situ tritium recovery and heat transfer performance of a miniaturized solid breeder blanket assembly. The assembly (capsule) was monitored for temperature and neutron flux profiles during irradiation and a sweep gas flowed through the capsule to an anaytical train wherein the amounts of tritium in its various chemical forms were determined. The capsule was designed to operate at different temperatures and sweep gas conditions. At the end of the experiment the amount of tritium retained in the solid was at a concentration of less than 0.1 wppM. More than 99.9% of tritium generated during the experiment was successfully recovered. The results of the experiment showed that the tritium inventories at the beginning and at the end of the experiment follow a relationship which appears to be characteristic of intragranular diffusion.

Clemmer, R.G.; Finn, P.A.; Malecha, R.F.; Misra, B.; Billone, M.C.; Bowers, D.L.; Fischer, A.K.; Greenwood, L.R.; Mattas, R.F.; Tam, S.W.

1984-09-01

389

Active optical fibres in modern particle physics experiments  

E-print Network

In modern particle physics experiments wavelength-shifting and scintillating fibres based on plastic polymers are used for tracking and calorimetry. In this review the role of photon trapping efficiencies, transmission functions and signal response times for common multimode active fibres is discussed. Numerical simulations involving three dimensional tracking of skew rays through curved fibres demonstrate the characteristics of trapped light. Of practical interest are the parametrisations of transmission functions and the minimum permissible radius of curvature. These are of great importance in today's experiments where high count rates and small numbers of photoelectrons are encountered. Special emphasis has been placed on the timing resolution of fibre detectors and its limitation due to variations in the path length of generated photons.

C. P. Achenbach

2004-04-05

390

A Study on Thermal Properties and ?( hcp) ? ?( bcc) Phase Transformation Energetics in Ti-5 mass% Ta-1.8 mass% Nb Alloy Using Inverse Drop Calorimetry  

NASA Astrophysics Data System (ADS)

Accurate measurements of enthalpy increment ( H T - H 298.15) values have been made on a Ti-5 mass% Ta-1.8 mass% Nb alloy using the inverse drop calorimetry technique in the temperature range from 463 K to 1457 K. The measured enthalpy increment values show a steady increase with temperature in both ?- hcp and ?- bcc solid solution regions. It is found that both the onset as well the completion of the ? ? ? phase change are demonstrated by a marked deviation of the enthalpy increment behavior from the otherwise smooth variation encountered in the respective low-temperature ?- and high-temperature ?-phase domains. The transformation start ( T s) and finish ( T f) temperatures of the ? ? ? phase change are found to be (1072±10) K and (1156±10) K, respectively. In the actual ? ? ? phase transformation region, the variation of the enthalpy with the progress of transformation is found to follow a sigmoidal shape which is in line with the diffusive nature of the phase transformation. An estimation of the total enthalpy change associated with the ? ? ? phase transformation (?° H tr) has been made by assuming a simple diffusion limited kinetic model for the phase change. The net enthalpy change for the ? ? ? transformation is found to be 76 J · g-1. The measured temperature variation of the enthalpy increment in both ?- and ?-phase regimes are fitted to simple analytical functional forms to obtain temperature-dependent estimates of the specific heat, C P . The total specific heat change associated with the ? ? ? phase transformation {?^{circ}{CP^{?}}^{?{?}}} is estimated to be 904 J · kg-1 · K-1.

Behera, Madhusmita; Raju, S.; Jeyaganesh, B.; Mythili, R.; Saroja, S.

2010-12-01

391

Reversible amorphous-crystalline phase changes in a wide range of Se1-xTex alloys studied using ultrafast differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

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.

Vermeulen, Paul. A.; Momand, Jamo; Kooi, Bart J.

2014-07-01

392

A short period of fasting before surgery conserves basal metabolism and suppresses catabolism according to indirect calorimetry performed under general anesthesia.  

PubMed

It is recommended that the period of fasting before elective surgery should be shortened to facilitate a rapid recovery by preventing catabolism. We examined the effects of a short period of fasting on metabolism by performing indirect calorimetry (IC) under general anesthesia. A prospective observational study involving 26 consecutive patients who underwent elective surgery and whose metabolism was evaluated using IC during anesthesia was conducted. The patients were divided into two groups, those who fasted for <8 h (group S) and those who fasted for >10 h (group L). Oxygen consumption, the volume of carbon dioxide emissions (VCO2), the respiratory quotient (RQ), resting energy expenditure (REE), and basal energy expenditure (BEE) were compared. The REE, VCO2, and RQ of group L (17.7 ± 2.3 kcal/kg/day, 118.5 ± 20.8 ml/min, and 0.71 ± 0.12, respectively) were significantly lower than those of group S (19.7 ± 2.3 kcal/kg/day, 143.6 ± 30.9 ml/min, and 0.81 ± 0.09, respectively) (P < 0.05). In group L, the relationship between REE and BEE was weaker (r (2) = 0.501) and the BEE-REE slope was less steep (REE = 0.419BEE + 509.477) than those seen in group S (r (2) = 0.749 and REE = 1.113BEE - 376.111, respectively). Our findings suggest that a short period of fasting (<8 h) before surgery is more strongly associated with the conservation of basal metabolism. PMID:25398400

Yoshimura, Shinichiro; Fujita, Yoshihito; Hirate, Hiroyuki; Kusama, Nobuyoshi; Azami, Takafumi; Sobue, Kazuya

2014-11-15

393

Characterization of the 1st and 2nd EF-hands of NADPH oxidase 5 by fluorescence, isothermal titration calorimetry, and circular dichroism  

PubMed Central

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 ?Hs 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 ?-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 PMID:22490336

2012-01-01

394

Reversible amorphous-crystalline phase changes in a wide range of Se(1-x)Te(x) alloys studied using ultrafast differential scanning calorimetry.  

PubMed

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. PMID:25028022

Vermeulen, Paul A; Momand, Jamo; Kooi, Bart J

2014-07-14

395

Probing the interaction of lysozyme with ciprofloxacin in the presence of different-sized Ag nano-particles by multispectroscopic techniques and isothermal titration calorimetry.  

PubMed

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 (?H(?)) and entropy (?S(?)) 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. PMID:23659247

Pasban Ziyarat, Fatemeh; Asoodeh, Ahmad; Sharif Barfeh, Zahra; Pirouzi, Maliheh; Chamani, Jamshidkhan

2014-04-01

396

Poker Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet simulates the basic poker experiment of dealing 5 cards from a standard deck. The random variable of interest is the type of hand.

Siegrist, Kyle

397

Interpretive Experiments  

ERIC Educational Resources Information Center

Describes an interpretative experiment involving the application of symmetry and temperature-dependent proton and fluorine nmr spectroscopy to the solution of structural and kinetic problems in coordination chemistry. (MLH)

DeHaan, Frank, Ed.

1977-01-01

398

Control experiment  

NSDL National Science Digital Library

There is a type of experiment in which a scientist uses a control variable approach. All conditions in the experiment will be the same except for one variable. When testing water tolerance of barley plants, for example, you could not water one plant, over-water one plant, under-water another plant, and water the last plant with the optimal amount of water and observe the results.

Peggy Greb (USDA; ARS)

2006-05-23

399

Chlorine Experiments  

NSDL National Science Digital Library

This site is provided by the American Chemistry Council's Science Center. The first experiment is called Sunscreen and Light Energy, which shows how chlorine is an ingredient in sunscreen and how it helps protect people from the sun's damage. The other experiment, called Antifreeze and the Freezing Point of Water, teaches how chlorine is an important component in antifreeze. Using antifreeze, foam cups, glass vials, and other simple ingredients, students learn how the liquid helps keep cars and other engines running during winter.

2008-01-01

400

Overview of the Cms Calorimetry  

NASA Astrophysics Data System (ADS)

The calorimeter system of the CMS detector is made of a high precision fine-grained electromagnetic calodmeter (ECAL) composed of lead tungstate crystals and a sampling hadronic calorimeter (HCAL) consisting of plates of brass absorbers and scintillator tiles with wavelength shifting fibers. A pre-shower detector composed of lead layers interleaved with silicon strips is installed in front of the ECAL End-cap crystals, and a forward calodmeter, made up of quartz fibers embedded within steel absorber, extend the coverage in the pseudorapidity region up to |?| < 5. The commissioning of the detector and the performance of the calorimeters during runs at the LHC with pp collisions will be reviewed. The resulting performance in the reconstruction of jets, electrons and photons will be briefly presented.

Ghezzi, A.

2012-08-01

401

DSC-HDTV video decoder system  

SciTech Connect

Zenith and AT&T developed the Digital Spectrum Compatible high-definition television (HDTV) system for evaluation by the US FCC Advanced Television Test Center. The system, specifically designed to minimize consumer receiver cost, uses a video decoder subsystem to decode the digital video bit stream and reconstruct video fields. Two new VLSI devices implement this video decoder in a cost-effective manner. We comment on the architecture and hardware complexity of these devices. 5 refs., 7 figs.

Duardo, O.; Knauer, S.C.; Mailhot, J.N.; Mondal, K.; Poon, T.C. [AT& T Bell Laboratories, Murry Hill, NJ (United States)] [AT& T Bell Laboratories, Murry Hill, NJ (United States)

1992-10-01

402

Tau Trigger at the ATLAS Experiment  

SciTech Connect

Many theoretical models, like the Standard Model or SUSY at large tan({beta}), predict Higgs bosons or new particles which decay more abundantly to final states including tau leptons than to other leptons. At the energy scale of the LHC, the identification of tau leptons, in particular in the hadronic decay mode, will be a challenging task due to an overwhelming QCD background which gives rise to jets of particles that can be hard to distinguish from hadronic tau decays. Equipped with excellent tracking and calorimetry, the ATLAS experiment has developed tau identification tools capable of working at the trigger level. This contribution presents tau trigger algorithms which exploit the main features of hadronic tau decays and describes the current tau trigger commissioning activities. Many of the SM processes being investigated at ATLAS, as well as numerous BSM searches, contain tau leptons in their final states. Being able to trigger effectively on the tau leptons in these events will contribute to the success of the ATLAS experiment. The tau trigger algorithms and monitoring infrastructure are ready for the first data, and are being tested with the data collected with cosmic muons. The development of efficiency measurements methods using QCD and Z {yields} {tau}{tau} events is well advanced.

Benslama, K.; Kalinowski, A.; /Regina U.; Belanger-Champange, C.; Brenner, R.; /Uppsala U.; Bosman, M.; Casado, P.; Osuna, C.; Perez, E.; Vorwerk, V.; /Barcelona, IFAE; Czyczula, Z.; Dam, M.; Xella, S.; /Copenhagen U.; Demers, S.; /SLAC; Farrington, S.; /Oxford U.; Igonkina, O.; /NIKHEF, Amsterdam; Kanaya, N.; Tsuno, S.; /Tokyo U.; Ptacek, E.; Reinsch, A.; Strom, David M.; Torrence, E.; /Oregon U. /Sydney U. /Lancaster U. /Birmingham U.

2011-11-09

403

Vestibular experiments  

NASA Technical Reports Server (NTRS)

Spacelab experiments designed to investigate space motion sickness, any associated changes in otolith-mediated responses occurring during weightlessness, and the carryover of any such changes to postflight conditions are described. The experiments aimed at assessing otolithic responses in space are intended to clarify presumed alterations in vestibular function during weightlessness. Vestibular function will be investigated at several levels: vestibulo-ocular reflexes, vestibulo-spinal pathways, cortical functions involving perception of motion and spatial orientation, visual vestibular interaction, and motion sickness susceptibility. A second major objective relates to space motion sickness and man's well-being and productivity in space.

Young, L. R.

1981-01-01

404

Neutrino Experiments  

SciTech Connect

Recent studies of neutrino oscillations have established the existence of finite neutrino masses and mixing between generations of neutrinos. The combined results from studies of atmospheric neutrinos, solar neutrinos, reactor antineutrinos and neutrinos produced at accelerators paint an intriguing picture that clearly requires modification of the standard model of particle physics. These results also provide clear motivation for future neutrino oscillation experiments as well as searches for direct neutrino mass and nuclear double-beta decay. I will discuss the program of new neutrino oscillation experiments aimed at completing our knowledge of the neutrino mixing matrix.

McKeown, R. D. [W. K. Kellogg Radiation Laboratory, California Institute of Technology, Pasadena, CA (United States)

2010-08-04

405

Materials Compatibility in High Test Hydrogen Peroxide  

NASA Technical Reports Server (NTRS)

Previous ratings of the compatibility of high test hydrogen peroxide (HTP) with materials are not adequate for current needs. The goal of this work was to develop a new scheme of evaluation of compatibility of HTP with various materials. Procedures were developed to enrich commercially available hydrogen peroxide to 90% concentration and to assay the product. Reactivity testing, accelerated aging of materials and calorimetry studies were done on HTP with representative metallic and non-metallic materials. It was found that accelerated aging followed by concentration determination using refractive index effectively discriminated between different Class 2 metallic materials. Preliminary experiments using Differential Scanning Calorimetry (DSC) suggest that a calorimetry experiment is the most sensitive means to assay the compatibility of HTP with materials.

Gostowski, Rudy

1999-01-01

406

Triangle Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet llustrates the triangle experiment: A stick is broken randomly into three parts. The events of interest are that the pieces form an acute triangle, an obtuse triangle, or no triangle.

Siegrist, Kyle

407

Bertrand's Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of Bertrand's experiment: a random chord on a cirle. The event of interest is whether the length of the chord is larger than the length of the inscribed equilateral triangle. Three models for generating the random chord can be used.

Siegrist, Kyle

408

Birthday Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of the birthday experiment: a sample of size n is chose at random and with replacement from the first m positive integers. The random variable of interest is the number of distinct sample values. The event of interest is that all sample values are distinct.

Siegrist, Kyle

409

Ballot Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of the ballot experiment: The votes in an election are randomly counted. The event of interest is that the winning candidate is always ahead in the vote count.

Siegrist, Kyle

410

Television experiment  

NASA Technical Reports Server (NTRS)

The fixed and variable Martian features investigated by the TV experiment on Mariner 9 are described. Articles are presented concerning the dust storm of October to November over the Southern Hemisphere; global surface geodesy and cartography; geology; and the satellite astronomy.

Briggs, G. A.; Cutts, J. A.; Steinbacher, R. H.; Thorpe, T. E.; Whitehead, A. B.; Devaucouleurs, G.; Davies, M. E.; Masursky, H.; Pollack, J. B.

1973-01-01

411

Biodiesel Experiment  

NSDL National Science Digital Library

The Advanced Technology Environmental and Energy Center (ATEEC) provides this classroom activity on biodiesel. The experiment involves using some chemicals which may be considered extremely dangerous; educators should be sure to practice laboratory safety when using this lesson. Users must download this resource for viewing, which requires a free log-in. There is no cost to download the item.

Lawrence, Richard

412

TGA, DTA and DSC studies of phosphiniminocyclotrithiazenes, R 3P=NS 3N 3 [R=(i) C 6H 5-, (ii) C 5H 10N-, (iii) OC 4H 8N-, (iv) H 3CNC 4H 8N-  

Microsoft Academic Search

Thermal decomposition behaviour of phosphiniminocyclotrithiazenes [R=(i) phenyl-, (ii) piperidino-, (iii) morpholino- and (iv) N-methylpiperazino-] have been studied for the first time by employing thermogravimetric (TG), differential thermal (DT) and differential scanning calorimetric (DSC) methods. These heterocycles which do not show any melting behaviour begin to decompose above 130°C by following different pathways. The study indicates the possibility of obtaining new

U. Swarnalatha; M. N. Sudheendra Rao; M. R. Udupa

1997-01-01

413

Soil experiment  

NASA Technical Reports Server (NTRS)

An experimental procedure was devised to investigate the effects of the lunar environment on the physical properties of simulated lunar soil. The test equipment and materials used consisted of a vacuum chamber, direct shear tester, static penetrometer, and fine grained basalt as the simulant. The vacuum chamber provides a medium for applying the environmental conditions to the soil experiment with the exception of gravity. The shear strength parameters are determined by the direct shear test. Strength parameters and the resistance of soil penetration by static loading will be investigated by the use of a static cone penetrometer. In order to conduct a soil experiment without going to the moon, a suitable lunar simulant must be selected. This simulant must resemble lunar soil in both composition and particle size. The soil that most resembles actual lunar soil is basalt. The soil parameters, as determined by the testing apparatus, will be used as design criteria for lunar soil engagement equipment.

Hutcheson, Linton; Butler, Todd; Smith, Mike; Cline, Charles; Scruggs, Steve; Zakhia, Nadim

1987-01-01

414

Mendel's experiments  

NSDL National Science Digital Library

In this web lab, Gregor Mendel directs students through interactive virtual experiments. Students experiment with pea plants to discover how the seven pairs of traits that Mendel studied are inherited. The lab can be completed linearly, or students can move to a particular segment using the Sections menu. After they observe pea plants and infer the number of traits present, students perform five plant crosses. Mendel instructs students to search for patterns in the transmission of traits. Next, students predict the outcome of a cross and are introduced to the terms dominant and recessive. Finally, students work with pedigrees, crossing plants to determine for each of the seven pairs of traits which characteristic is dominant or recessive. A notebook feature lets students check their answers. Copyright 2005 Eisenhower National Clearinghouse

Center, Education D.

2002-01-01

415

Lift Experiment  

NSDL National Science Digital Library

In this experiment, learners investigate how the size of a wing affects lift. Learners count the number of pennies an egg crate plane wing can hold until the plane will no longer fly. Learners calculate the amount of weight/mass added to plane and conduct two more trials to find the average weight/mass lifted. This lesson guide includes a data table, conclusion questions, and extension ideas.

Ricles, Shannon; Locke, Dan; Livingston, John

2013-01-30

416

Weathering Experiment  

NSDL National Science Digital Library

After discussing weathering and erosion in class, students are asked to do a small amount of research on different types of chemical weathering, physical weathering, and erosion processes (mostly out of their textbook). Outside of class students then dirty at least four similar dishes with the same type, thickness and aerial extent of food, preferably baked on to ensure maximum stick. One dish is set aside as a control (no weathering or erosion will occur for that dish). For each of the remaining three dishes, students devise an experiment that mimics some sort of chemical weathering, physical weathering, or erosion process (freeze/thaw, sand abrasion, oxidation, etc.). Prior to the experiments, the thickness of food is measured. Experiments are timed, and at the end of the experiment each plate is turned over to determine how much which method removed the greatest aerial extent of food. Experimental results are compared to the control plate to determine the actual effectiveness. Erosion/weathering rates are determined by dividing the thickness of food removed by the experimental time. Students then calculate how long it would take to remove a pile of food the size of the Geology building (assume a 50 m radius sphere), and to remove an amount of food equivalent to the depth of the Grand Canyon. Students then compare these results to rock erosion and weathering rates, performing similar calculations using these "real" rates (see the full project description for details). Photos of each step and the scientists are encouraged in their 2-3 page writeup.

Stelling, Pete

417

Matching Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of the matching experiment, which consists of a random permutation of the first n positive integers. The random variable of interest is the number of matches (the number of integers in the random permutation that are in their correct positions). The applet illustrates the distribution of the number of matches and the convergence to the Poisson distribution.

Siegrist, Kyle

418

Voter Experiment  

NSDL National Science Digital Library

This resource consists of a Java applet and expository text. The applet is a simulation of the voter experiment, an interacting partile system that consists of a rectangular array of sites. At each discrete time unit, a site is chosen at random, a neighboring site is chosen, and the color of the first site is changed to that of the neighbor. The applet illustrates clustering of the colors and convergence to consensus.

Siegrist, Kyle

419

Taphonomy Experiment  

NSDL National Science Digital Library

The taphonomy project is a semester-long experiment the students design and run themselves, using the decomposition studies area run by the Criminal Justice department on campus. Following a discussion of taphonomic processes during the first week, the students come up with original questions to test. Working in pairs, they design the experiment, including methods, materials, sampling interval, and taphonomic evaluation. The students set up the experiment in week 3 and monitor it over the course of the semester. They will be required to keep an experimental journal, data from which they will upload to a wiki page. The students will be required to periodically evaluate and comment on other student's projects. The professor will also periodically evaluate the groups' progress periodically through the wiki. The end result is a 20-minute presentation in the style of an oral paper at a conference given the week before finals. This project develops the students' skills in experimental design, data analysis and written, oral and visual communication.

Koy, Karen

420

Enthalpies of formation from the component oxides of MgWO 4, CaWO 4 (scheelite), SrWO 4, and BaWO 4, determined by high-temperature direct synthesis calorimetry  

Microsoft Academic Search

The enthalpies of formation, from the constituent oxides, of tungstates of alkaline earth metals, MeWO4 (Me is Mg, Ca, Sr, Ba), have been determined by direct synthesis calorimetry at 1473 ± 2 K. The following values of ?Hf at 298 K (kJ mol?1) are reported: MgWO4, ?73.9 ± 4.8; CaWO4 (scheelite), ?168.5 ± 3.3; SrWO4, ?217.9 ± 3.6; BaWO4, ?256.2

Qiti Guo; Ole Jakob Kleppa

1996-01-01

421

Development of a Relic Neutrino Detection Experiment at PTOLEMY: Princeton Tritium Observatory for Light, Early-Universe, Massive-Neutrino Yield  

E-print Network

The PTOLEMY experiment (Princeton Tritium Observatory for Light, Early-Universe, Massive-Neutrino Yield) aims to achieve the sensitivity required to detect the relic neutrino background through a combination of a large area surface-deposition tritium target, MAC-E filter methods, cryogenic calorimetry, and RF tracking and time-of-flight systems. A small-scale prototype is in operation at the Princeton Plasma Physics Laboratory with the goal of validating the technologies that would enable the design of a 100 gram PTOLEMY. With precision calorimetry in the prototype setup, the limitations from quantum mechanical and Doppler broadening of the tritium target for different substrates will be measured, including graphene substrates. Beyond relic neutrino physics, sterile neutrinos contributing to the dark matter in the universe are allowed by current constraints on partial contributions to the number of active neutrino species in thermal equilibrium in the early universe. The current PTOLEMY prototype is expected ...

Betts, S; Carnevale, R H; Chang, C; Chen, C; Chidzik, S; Ciebiera, L; Cloessner, P; Cocco, A; Cohen, A; Dong, J; Klemmer, R; Komor, M; Gentile, C; Harrop, B; Hopkins, A; Jarosik, N; Messina, M; Osherson, B; Raitses, Y; Sands, W; Schaefer, M; Taylor, J; Tully, C G; Woolley, R; Zwicker, A

2013-01-01

422

Descriptive Experience Sampling 1 Descriptive Experience Sampling  

E-print Network

Sampling: Exploring Moments of Inner Experience The attempt to apprehend human experience the way, and often (or usually!) argumentative force fields. DES accepts the primacy of human experience and seeks aspect of human experience, which it calls `pristine inner experience'. By `inner experience' we mean

Ahmad, Sajjad

423

Experiments on Nucleation in Different Flow Regimes  

NASA Technical Reports Server (NTRS)

The vast majority of metallic engineering materials are solidified from the liquid phase. Understanding the solidification process is essential to control microstructure, which in turn, determines the properties of materials. The genesis of solidification is nucleation, where the first stable solid forms from the liquid phase. Nucleation kinetics determine the degree of undercooling and phase selection. As such, it is important to understand nucleation phenomena in order to control solidification or glass formation in metals and alloys. Early experiments in nucleation kinetics were accomplished by droplet dispersion methods [1-6]. Dilitometry was used by Turnbull and others, and more recently differential thermal analysis and differential scanning calorimetry have been used for kinetic studies. These techniques have enjoyed success; however, there are difficulties with these experiments. Since materials are dispersed in a medium, the character of the emulsion/metal interface affects the nucleation behavior. Statistics are derived from the large number of particles observed in a single experiment, but dispersions have a finite size distribution which adds to the uncertainty of the kinetic determinations. Even though temperature can be controlled quite well before the onset of nucleation, the release of the latent heat of fusion during nucleation of particles complicates the assumption of isothermality during these experiments. Containerless processing has enabled another approach to the study of nucleation kinetics [7]. With levitation techniques it is possible to undercool one sample to nucleation repeatedly in a controlled manner, such that the statistics of the nucleation process can be derived from multiple experiments on a single sample. The authors have fully developed the analysis of nucleation experiments on single samples following the suggestions of Skripov [8]. The advantage of these experiments is that the samples are directly observable. The nucleation temperature can be measured by noncontact optical pyrometry, the mass of the sample is known, and post processing analysis can be conducted on the sample. The disadvantages are that temperature measurement must have exceptionally high precision, and it is not possible to isolate specific heterogeneous sites as in droplet dispersions.

Bayuzick, Robert J.

1999-01-01

424

Experiments on Nucleation in Different Flow Regimes  

NASA Technical Reports Server (NTRS)

The vast majority of metallic engineering materials are solidified from the liquid phase. Understanding the solidification process is essential to control microstructure, which in turn, determines the properties of materials. The genesis of solidification is nucleation, where the first stable solid forms from the liquid phase. Nucleation kinetics determine the degree of undercooling and phase selection. As such, it is important to understand nucleation phenomena in order to control solidification or glass formation in metals and alloys. Early experiments in nucleation kinetics were accomplished by droplet dispersion methods. Dilitometry was used by Turnbull and others, and more recently differential thermal analysis and differential scanning calorimetry have been used for kinetic studies. These techniques have enjoyed success; however, there are difficulties with these experiments. Since materials are dispersed in a medium, the character of the emulsion/metal interface affects the nucleation behavior. Statistics are derived from the large number of particles observed in a single experiment, but dispersions have a finite size distribution which adds to the uncertainty of the kinetic determinations. Even though temperature can be controlled quite well before the onset of nucleation, the release of the latent heat of fusion during nucleation of particles complicates the assumption of isothermality during these experiments. Containerless processing has enabled another approach to the study of nucleation kinetics. With levitation techniques it is possible to undercool one sample to nucleation repeatedly in a controlled manner, such that the statistics of the nucleation process can be derived from multiple experiments on a single sample. The authors have fully developed the analysis of nucleation experiments on single samples following the suggestions of Skripov. The advantage of these experiments is that the samples are directly observable. The nucleation temperature can be measured by noncontact optical pyrometry, the mass of the sample is known, and post-processing analysis can be conducted on the sample. The disadvantages are that temperature measurement must have exceptionally high precision, and it is not possible to isolate specific heterogeneous sites as in droplet dispersions. Levitation processing of refractory materials in ultra high vacuum provides an avenue to conduct these kinetic studies on single samples. Two experimental methods have been identified where ultra high vacuum experiments are possible; electrostatic levitation in ground-based experiments and electromagnetic processing in low earth orbit on TEMPUS. Such experiments, reported here, were conducted on zirconium. Liquid zirconium is an excellent solvent and has a high solubility for contaminants contained in the bulk material as well as those contaminants found in the vacuum environment. Oxides, nitrides, and carbides do not exist in the melt, and do not form on the surface of molten zirconium, for the materials and vacuum levels used in this study. Ground-based experiments with electrostatic levitation have shown that the statistical nucleation kinetic experiments are viable and yield results which are consistent with classical nucleation theory. The advantage of low earth orbit experiments is the ability to vary the flow conditions in the liquid prior to nucleation. The put-pose of nucleation experiments in TEMPUS was to examine.

Bayuzick, R. J.; Hofmeister, W. H.; Morton, C. M.; Robinson, M. B.

1998-01-01

425

Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Heat Capacity of Metals and Demonstration of Law of Dulong and Petit  

ERIC Educational Resources Information Center

Today's general chemistry students are introduced to many of the principles and concepts of thermodynamics. In first-year general chemistry undergraduate courses, thermodynamic properties such as heat capacity are frequently discussed. Classical calorimetric methods of analysis and thermal equilibrium experiments are used to determine heat…

D'Amelia, Ronald P.; Stracuzzi, Vincent; Nirode, William F.

2008-01-01

426

Parabolic flight experiments as a tool for preparation of ISS experiment IVIDIL  

NASA Astrophysics Data System (ADS)

In the frame of ESA Physical Sciences project "Diffusion and Soret Coefficient Measurements for Improvement of Oil Recovery" (DSC), the experiment IVIDIL is planned to examine the INfluence of VIbration on DIffusion in Liquids. IVIDIL experiment will be performed in twosteps. During the first step, a concentration gradient is established by imposing a temperature gradient along the experimental cell that is filled with a homogeneous binary mixture. Due to Soret effect, the binary mixture tends to separate with time. At the second step, the system is reverted to an isothermal state, where molecular diffusion will progressively reduce the previously established concentration gradient. Thus, the measurements of diffusion and thermodiffusion coefficients are foreseen. Precise measurements of mass transport coefficients under terrestrial conditions are often perturbed by buoyancy-induced flows. The microgravity environment minimizes the effect of gravity and allows the true diffusion limit to be achieved. On the other hand, the background g-jitters encountered in many space experiments may alter the benefits of the microgravity environment. A detailed investigation of the spectral influence of g-jitter on molecular diffusion and thermodiffusion measurements on ISS will be performed inside the Microgravity Science Glovebox (MSG) on board the Columbus laboratory. The entire experiment comprises two physical phenomena: thermal and isothermal diffusion and thermo-vibrational convection. The latter phenomenon is a relatively fast process and has been studied in parabolic flights (2007-2008). Parabolic flights in a modified Airbus A-300 aircraft offer repeated periods of approximately 20 seconds of weightlessness with a microgravity level of 0.01g. Our experiments were conducted during 46th and 48th Parabolic Flight Campaigns organized by the European Space Agency (www.spaceflight.esa.int/users). During each parabola (out of 93 for the whole campaign), a fully automated experimental cycle was running. The level of vibrational stimuli and the applied temperature difference were controlled by computer. The digital optical method was used for recording the temperature field. The experimental design was as close as possible to the design of flight model for IVIDIL. The experiments for the same frequency and amplitude were repeated several times since each parabola has a specific profile of g-jitter. By doing so, we presented strong evidence of the existence of thermo-vibrational convection in reduced gravity. In addition, comprehensive tests of the set-up design were performed.

Shevtsova, Valentina; Mialdun, Alexander; Melnikov, Denis; Ryzhkov, Ilya

427

Initial results on calorimetry and imaging of MeV gamma rays with a 10-liter liquid xenon time projection chamber (LXe-TPC)  

Microsoft Academic Search

The experiment LXe-CAT (Liquid Xenon-Coded Aperture Telescope), which we have proposed for (gamma) -ray astrophysics observations in the 300 keV - 10 MeV energy range, uses a Liquid Xenon Time Projection Chamber (LXe-TPC) as a position sensitive (gamma) -ray detector, and a coded aperture mask to provide a telescope with an angular resolution of 30 ft over a field of

Elena Aprile; Aleksey E. Bolotnikov; D. Chen; H. Tawara; Fang Xu

1994-01-01

428

Mechanics and Assembly of the Silicon Vertex Detector for the PHENIX Experiment at RHIC  

NASA Astrophysics Data System (ADS)

The PHENIX experiment at the Relativistic Heavy-Ion Collider explores the phase diagram of strongly interacting matter through collisions of beam of heavy nuclei. A second physics program addresses the spin structure of the nucleon through collisions of beams of polarized protons. The PHENIX apparatus has been particularly designed for lepton-pair measurements and comprises detectors for charged-particle tracking, particle identification, calorimetry and collision centrality monitors. Los mass detector systems and high-rate capability have been central to its concept. Recently a silicon vertex detector has been added to the experiment. It will extend the capabilities of PHENIX towards more refined studies involving heavy flavor physics with direct detection of decays. The presented article addresses technical aspects of the vertex detector's mechanical construction and the assembly of its components. It contains various detailed information and may be of interest to a larger scientific and engineering community in the fields of high -energy and heavy-ion physics.

Sondheim, Walter; The Phenix Collaboration

429

Thermal properties of globulin from buckwheat ( Fagopyrum esculentum Moench)  

Microsoft Academic Search

The thermal properties of buckwheat (Fagopyrum esculentum Moench) proteins with different lipid contents (2.5, 6.5 and 17.8%) were studied by differential scanning calorimetry (DSC)\\u000a under various medium conditions. From DSC curves, many DSC characteristics including denaturation temperature (T\\u000a d), enthalpy change (?H) and the width at half peak height (?T\\u000a 1\\/2) of endothermic peaks were obtained and evaluated. The DSC

C.-H. Tang

2007-01-01

430

Skylab Workshop experience in experiment accommodation  

NASA Technical Reports Server (NTRS)

This paper examines the experiment support facilities available from the Orbital Workshop (OWS) module of the Skylab. Experiments and associated support provisions have been selected and described to illustrate the various accommodations and degree of complexities involved in the integration of these experiments into the Workshop. The interfaces described start with the simple and proceed to the complex. On the basis of the experience gained in integrating the experiments into the Workshop, conclusions are drawn and suggestions are made on ways to facilitate future experiment operations and at the same time simplify and reduce the cost of integration efforts.

Hanlon, W. H.; Hassel, R. R.

1974-01-01

431

Improving ITC studies of cyclodextrin inclusion compounds by global analysis of conventional and non-conventional experiments  

PubMed Central

Summary The study of 1:1 cyclodextrin inclusion compounds by isothermal titration calorimetry was explored in a theoretical and experimental point of view to compare the efficiency of conventional and non-conventional experiments. All direct and competitive protocols were described and evaluated in terms of accuracy on both binding constant and inclusion enthalpy. Significant improvement in the calorimetric characterization may be obtained by means of the global analysis of non-conventional experiments coupled to the standard titration protocol. While the titration-release approach proved to be the most accurate strategy for classical complexations, the valuable contribution of other non-conventional experiments was demonstrated for issues concerning weak stability, enthalpy, or solubility. PMID:25550724

Bertaut, Eléonore

2014-01-01

432

Diabetes Experience Spring 2014 Interprofessional Diabetes Experience  

E-print Network

Diabetes Experience Spring 2014 Interprofessional Diabetes Experience Phar 6226/Nurs 5011 Spring the opportunity to learn in-depth knowledge of diabetes mellitus through active, hands-on learning experience of living with diabetes, in which they will give "insulin" injections and check blood glucoses

Thomas, David D.

433

Experiences and Experiments - There is a Difference  

NSDL National Science Digital Library

Students have had many experiences in science and have participated in and designed simple investigations. This lesson directs students in identifying the steps of experimentation. While microorganisms are the topic and the subject of the experimentation, the emphasis and learning should center on scientific steps and processes of scientific experiments. Designing and conducting an experiment involves an integration or combining of science process skills.

Teresa Hislop & KIRSTIN REED

2011-09-19

434

Glacier Goo Erosion Experiments  

NSDL National Science Digital Library

Using a glacier proxy, students design an experiment to connect glacial erosion with glacial flow. Students choose from a variety of materials, determined what question they want their experiment or experiments to answer, design the procedure, test the experiment, and write up a lab report on the experiment.

Rachel Headley

435

Notes on Experiments.  

ERIC Educational Resources Information Center

Describes: (1) experiments using a simple phonocardiograph; (2) radioactivity experiments involving a VELA used as a ratemeter; (3) a 25cm continuously operating Foucault pendulum; and (4) camera control of experiments. Descriptions of equipment needed are provided when applicable. (JN)

Physics Education, 1984

1984-01-01