Directory of Open Access Journals (Sweden)
Fauzi F.A.
2016-01-01
Full Text Available This paper presented the research works on the investigation of the thermal behavior of the natural fibres; i.e. pineapple leaf fibre, kenaf fibre and mengkuang fibres reinforced epoxy. The thermogravimetric analysis and differential scanning calorimetric analysis were used to measure the thermal behavior of the treated and untreated pineapple, kenaf and mengkuang fibres reinforced epoxy. The samples for both analysis were subjected to maximum temperature 600°C at the heating rate of 10°C/min. The results showed that the treated fibres show higher maximum peak temperature as compared to the untreated fibres. Additionally, the glass transition temperature showed a lower value for all treated fibre. It can be concluded that investigation of thermal properties of these natural fibres could improve the utilization of natural fibre composites in various applications i.e. sports applications.
Differential scanning calorimetry (DSC) of semicrystalline polymers.
Schick, C
2009-11-01
Differential scanning calorimetry (DSC) is an effective analytical tool to characterize the physical properties of a polymer. DSC enables determination of melting, crystallization, and mesomorphic transition temperatures, and the corresponding enthalpy and entropy changes, and characterization of glass transition and other effects that show either changes in heat capacity or a latent heat. Calorimetry takes a special place among other methods. In addition to its simplicity and universality, the energy characteristics (heat capacity C(P) and its integral over temperature T--enthalpy H), measured via calorimetry, have a clear physical meaning even though sometimes interpretation may be difficult. With introduction of differential scanning calorimeters (DSC) in the early 1960s calorimetry became a standard tool in polymer science. The advantage of DSC compared with other calorimetric techniques lies in the broad dynamic range regarding heating and cooling rates, including isothermal and temperature-modulated operation. Today 12 orders of magnitude in scanning rate can be covered by combining different types of DSCs. Rates as low as 1 microK s(-1) are possible and at the other extreme heating and cooling at 1 MK s(-1) and higher is possible. The broad dynamic range is especially of interest for semicrystalline polymers because they are commonly far from equilibrium and phase transitions are strongly time (rate) dependent. Nevertheless, there are still several unsolved problems regarding calorimetry of polymers. I try to address a few of these, for example determination of baseline heat capacity, which is related to the problem of crystallinity determination by DSC, or the occurrence of multiple melting peaks. Possible solutions by using advanced calorimetric techniques, for example fast scanning and high frequency AC (temperature-modulated) calorimetry are discussed.
Directory of Open Access Journals (Sweden)
Luis Octavio Martínez Álvarez
2011-03-01
Full Text Available Como parte de la pre-estabilidad de la preformulación de auranofin tabletas, se realizó un estudio de compatibilidad química, para lo cual se emplearon técnicas de análisis térmico como la calorimetría diferencial de barrido y la termogravimetría. Previo a dichos estudios se caracterizó térmicamente por calorimetría diferencial de barrido el principio activo y cada uno de los excipientes. Posteriormente se procedió a la realización del estudio de compatibilidad química, mediante la preparación de mezclas físicas binarias entre el principio activo y cada uno de los excipientes. Se detectó por ambos métodos que el principio activo tuvo una transición física de fusión, no reportada en la literatura, lo que permitió poder calcular su pureza por calorimetría diferencial de barrido. Mediante la técnica calorimétrica fue posible inferir la ausencia de incompatibilidad química entre el principio activo y los excipientes estudiados. Además, mediante el cálculo de la energía de activación se estableció el siguiente orden de estabilidad térmica: auranofin:PVP> auranofin:lactosa> auranofin:explotab> auranofin:estearato> auranofin:aerosil> auranofin:celulosa, por lo que se recomienda el uso de estos excipientes en la elaboración de la formulación farmacéutica.As part of the pre-stability study of the Auranofin tablet pre-formulation, a chemical compatibility study was conducted using thermal analysis techniques such as the differential scanning calorimetry and the thermogravimetry. Prior to these studies, the active principle and each of the excipients were thermally characterized with the aid of the differential scanning calorimetry. Then, there proceeded to carry out the chemical compatibility study by preparing binary physical mixtures between the active principle and each of the excipients. Both methods showed that the active principle had a melting physical transition, not reported in the literature, which allowed
D'Amelia, Ronald; Franks, Thomas; Nirode, William F.
2007-01-01
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…
International Nuclear Information System (INIS)
Wei, Z.G.; Sandstroem, R.
1999-01-01
Modulated differential scanning calorimetry (MDSC) is a recently developed calorimetric technique, which has demonstrated some significant advantages over the conventional differential scanning calorimetry (DSC). By separating the reversing quantity from the non-reversing component in the total thermal events, it provides some new information that can not be obtained from the conventional DSC. The technique has been applied to various polycrystalline and single crystalline shape-memory alloys, including Cu-Zn-Al, Cu-Al-Ni, Ti-Ni(Cu), Ni-Mn-Ga and Fe-Mn-Si, to characterize the martensitic transformations, bainitic transformation, chemical and magnetic ordering transitions, atomic reordering and other kinetic relaxation processes in the alloys. The preliminary results of the MDSC measurements are summarized and the interpretation of the MDSC results and some factors affecting the results are discussed. (orig.)
Volumetric and calorimetric properties of aqueous ionene solutions.
Lukšič, Miha; Hribar-Lee, Barbara
2017-02-01
The volumetric (partial and apparent molar volumes) and calorimetric properties (apparent heat capacities) of aqueous cationic polyelectrolyte solutions - ionenes - were studied using the oscillating tube densitometer and differential scanning calorimeter. The polyion's charge density and the counterion properties were considered as variables. The special attention was put to evaluate the contribution of electrostatic and hydrophobic effects to the properties studied. The contribution of the CH 2 group of the polyion's backbone to molar volumes and heat capacities was estimated. Synergistic effect between polyion and counterions was found.
Goyal, Megha; Chaudhuri, Tapan K; Kuwajima, Kunihiro
2014-01-01
Thermal denaturation of Escherichia coli maltodextrin glucosidase was studied by differential scanning calorimetry, circular dichroism (230 nm), and UV-absorption measurements (340 nm), which were respectively used to monitor heat absorption, conformational unfolding, and the production of solution turbidity. The denaturation was irreversible, and the thermal transition recorded at scan rates of 0.5-1.5 K/min was significantly scan-rate dependent, indicating that the thermal denaturation was kinetically controlled. The absence of a protein-concentration effect on the thermal transition indicated that the denaturation was rate-limited by a mono-molecular process. From the analysis of the calorimetric thermograms, a one-step irreversible model well represented the thermal denaturation of the protein. The calorimetrically observed thermal transitions showed excellent coincidence with the turbidity transitions monitored by UV-absorption as well as with the unfolding transitions monitored by circular dichroism. The thermal denaturation of the protein was thus rate-limited by conformational unfolding, which was followed by a rapid irreversible formation of aggregates that produced the solution turbidity. It is thus important to note that the absence of the protein-concentration effect on the irreversible thermal denaturation does not necessarily means the absence of protein aggregation itself. The turbidity measurements together with differential scanning calorimetry in the irreversible thermal denaturation of the protein provided a very effective approach for understanding the mechanisms of the irreversible denaturation. The Arrhenius-equation parameters obtained from analysis of the thermal denaturation were compared with those of other proteins that have been reported to show the one-step irreversible thermal denaturation. Maltodextrin glucosidase had sufficiently high kinetic stability with a half-life of 68 days at a physiological temperature (37°C).
International Nuclear Information System (INIS)
Lando, D.Y.; Fridman, A.S.; Galyuk, E.N.; Dalyan, Y.B.; Grigoryan, I.E.; Haroutiunian, S.G.
2013-01-01
The differential scanning calorimetry (DSC) is more sensitive than UV absorption spectrophotometry as a tool for the measurement of DNA melting curves. The advantage of DSC is a direct determination of differential melting curves (DMC) obtained without numerical differentiation. However, the difference between the helix-coil transition enthalpies of AT and GC base pairs can cause distortions in the shape of melting curve. Up to date, the errors caused by those distortions were not evaluated. In this study, a simple procedure of recalculation of a calorimetric DMC into a real DMC is developed. It demonstrates that the 'real' melting curve and differential melting curve deviate very slightly from the same two curves calculated from DSC data. The melting temperature and the temperature melting range are usually the same even if the difference in the enthalpies is several times higher than a real one
Stoichiometrical trends in differential scanning calorimetry measurements on phase-change materials
Energy Technology Data Exchange (ETDEWEB)
Klein, Michael; Linn, Malte; Wuttig, Matthias [I. Physikalisches Institut, RWTH Aachen University, Aachen (Germany)
2009-07-01
Phase-change materials are alloys which can be rapidly switched between two metastable states, the amorphous and the crystalline phase. At the same time they show pronounced contrast in their electrical and optical properties. They are widely used as the functional layer in rewritable optical discs. Prototypes of electrical devices employing phase change materials as non-volatile memory are already entering the market. Here we present calorimetric measurements, mainly on ternary Ge-Sb-Te alloys. Scratched-off thin film samples were heated in a differential scanning calorimeter to measure the transition from as-deposited amorphous to metastable crystalline phase and finally to the stable crystalline phase. The different transition temperatures will be analysed as a function of stoichiometry in order to improve the understanding of their interconnection.
Debrus, S.; Marchewka, M. K.; Drozd, M.; Ratajczak, H.
2007-04-01
The efficiency of second harmonic generation for melaminium bis(trichloroacetate) was estimated relatively to KDP: deff = 3.09 deff (KDP). Room temperature FT IR and FT Raman spectra were recorded. Some spectral features of this new crystal are referred to corresponding one for melamine crystal as well as for other trichloroacetates. Differential scanning calorimetric measurements performed on powder sample indicate the phase transition point at approximately 276 and 239 K for heating and cooling, respectively.
Energy Technology Data Exchange (ETDEWEB)
Patil, Prajakta R.; Krishnamurthy, V.N.; Joshi, Satyawati S. [Department of Chemistry, University of Pune, Pune 411007 (India)
2006-12-15
A comparative study of the thermal decomposition of ammonium perchlorate (AP)/hydroxy terminated polybutadiene (HTPB) based composite propellants has been carried out in presence and absence of nano iron oxide at different heating rates in a dynamic nitrogen atmosphere using differential scanning calorimetry. The pronounced effect was a lowering of the high temperature decomposition by 49 C. A higher heat release up to 40% was observed in presence of nano ferric oxide (3.5 nm). The kinetic parameters were evaluated using the Kissinger method. The increase of the rate constant in the catalyzed propellant confirmed the enhancement of the catalytic activity of ammonium perchlorate. The scanning electron micrographs of nano Fe{sub 2}O{sub 3} incorporated in HTPB revealed a well-separated characteristic necklace-like structure of {alpha}-Fe{sub 2}O{sub 3} particles at high magnification. (Abstract Copyright [2006], Wiley Periodicals, Inc.)
Thermogravimetric and Differential Scanning Calorimetric Behavior of Ball-Milled Nuclear Graphite
Energy Technology Data Exchange (ETDEWEB)
Kim, Eung Seon; Kim, Min Hwan; Kim, Yong Wan [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of); Park, Yi Hyun; Cho, Seung Yon [National Fusion Research Institute, Daejeon (Korea, Republic of)
2013-10-15
An examination was made to characterize the oxidation behavior of ball-milled nuclear graphite powder through a TG-DSC analysis. With the ball milling time, the BET surface area increased with the reduction of particle size, but decreased with the chemisorptions of O{sub 2} on the activated surface. The enhancement of the oxidation after the ball milling is attributed to both increases in the specific surface area and atomic scale defects in the graphite structure. In a high temperature gas-cooled reactor, nuclear graphite has been widely used as fuel elements, moderator or reflector blocks, and core support structures owing to its excellent moderating power, mechanical properties and machinability. For the same reason, it will be used in a helium cooled ceramic reflector test blanket module for the ITER. Each submodule has a seven-layer breeding zone, including three neutron multiplier layers packed with beryllium pebbles, three lithium ceramic pebbles packed tritium breeder layers, and a reflector layer packed with 1 mm diameter graphite pebbles to reduce the volume of beryllium. The abrasion of graphite structures owing to relative motion or thermal cycle during operation may produce graphite dust. It is expected that graphite dust will be more oxidative than bulk graphite, and thus the oxidation behavior of graphite dust must be examined to analyze the safety of the reactors during an air ingress accident. In this study, the thermal stability of ball-milled graphite powder was investigated using a simultaneous thermogravimeter-differential scanning calorimeter.
Calorimetric determination of the δ hydride dissolution enthalpy in Zircaloy-4
International Nuclear Information System (INIS)
Vizcaino, Pablo; Banchik, Abraham D.
2003-01-01
In this work, the dissolution enthalpy, ΔH δ→α , of the δ hydride phase in the αZr matrix in Zircaloy-4 has been determined with a differential scanning calorimeter (DSC) in two different ways: by means of a vant Hoff equation, measuring the terminal solubility temperature in dissolution, TSSd, and by direct measurement of the dissolution heat, Q δ→α , as the area between the base line and the calorimetric curve. The application of the DSC technique to the hydride dissolution heat measurements, a transformation which covers an extended temperature range, is completely original and requires a special treatment of the calorimetric curve. These measurements were done on samples, which practically cover the whole solubility range of hydrogen in αZr phase (80-640 ppm). The values obtained, 36.9 kJ/mol H and 39.3 kJ/mol H respectively, are self-consistent and in good agreement with the values of the more recent revisions, but reduces considerably the scatter of the literature data. (author)
Directory of Open Access Journals (Sweden)
Luis Octavio Martínez Álvarez
2013-03-01
Full Text Available Introducción: en la primera etapa de preformulación de un medicamento se seleccionan los excipientes y es importante la realización de los estudios de compatibilidad química entre el ingrediente activo farmacéutico (IFA y excipientes. Una de las técnicas más rápidas para realizar dichos estudios es la Calorimetría diferencial de barrido (DSC, y como técnica complementaria la Termogravimetría (TG. Objetivo: empleando DSC y TG, se realiza un estudio de compatibilidad química entre IFA y excipientes preseleccionados, para comprobar la existencia o no de interacción química. Métodos: el equipo empleado fue el TA3000Mettler, acoplado a la celda DSC20 y al horno TG50. El IFA utilizado fue Piracetam, y los excipientes: Kollidon VA 64, Estearato de magnesio, Celulosa microcristalina, Polietilenglicol 20 000 y Aerosil. Dichos excipientes se caracterizaron por DSC al igual que el IFA, al cual se le detectó la transición física de fusión. Para el estudio de compatibilidad se prepararon mezclas físicas binarias en una relación de concentración 1:1 Resultados: la figura 1 muestra la detección del punto de fusión por DSC del IFA. Se obtuvieron dos transiciones endotérmicas, comprobándose por TG cuál era la de fusión. La figura 2 muestra los termogramas de las mezclas formadas entre IFA y excipientes. Conclusiones: no se detectó aparición de nuevos picos, por lo que se infiere que no hay incompatibilidad química entre las sustancias estudiadas y se recomienda el uso de los excipientes para el desarrollo de la formulación farmacéutica.Introduction: the first phase of the drug preformulation comprises the selection of excipients and the conduction of studies on chemical compatibility between pharmacologically active ingredient and the excipients. One of the quickest techniques is the differential scanning calorimetry and the supplementary technique called thermogravimetic analysis. Objective: to conduct a chemical compatibility
Chakravarty, Paroma; Pandya, Keyur; Nagapudi, Karthik
2018-03-05
The fragility index ( m) and conversely the strength parameter ( D) are widely used to categorize glass forming liquids and are used to characterize temperature dependency of viscosity and relaxation time as the supercooled liquid approaches glass transition. The currently used calorimetric methods in pharmaceutical literature lead to wide variability in measured values of m. In this work, a modulated differential scanning calorimetry (DSC) method is introduced that can directly determine m with minimal variability. Although calorimetric fragility is easy to measure due to availability and ease of use of DSC, there is no correlation between calorimetric and dielectric fragility (calculated spectroscopically from relaxation times). In addition, there is also no correlation between calorimetric fragility and the so-called "thermodynamic fragility" that can be calculated using only thermodynamic parameters. No relationship can be found between the crystallization propensity in the supercooled liquid state and D. However, the crystallization propensity shows a reasonable correlation with the Kohlrausch distribution parameter β k , which defines the breadth of the relaxation time distribution.
International Nuclear Information System (INIS)
Rojas, Aaron; Orozco, Eulogio
2003-01-01
An experimental procedure is proposed for direct measurement of the heat involved in the vaporization of a solid organic compound above its normal melting temperature. This technique consists on the fusion of a solid aromatic hydrocarbon, which is then vaporized by a sudden decrease of the pressure. The direct register of heat flow as function of time by differential scanning calorimetry allows the quantifying of the enthalpy of vaporization of compounds such as phenanthrene, β-naphthol, pyrene, and anthracene. Enthalpies of vaporization were measured in an isothermal mode over a range of temperatures from 10 to 20 K above the melting temperatures of each compound, while enthalpies of fusion were determined from separate experiments performed in a scanning mode. Enthalpies of sublimation are computed from results of fusion and vaporization, and then compared with results from the literature, which currently are obtained by calorimetric or indirect techniques
Calorimetric monitoring of the serum proteome in schizophrenia patients
Energy Technology Data Exchange (ETDEWEB)
Krumova, Sashka [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria); Rukova, Blaga [Department of Medical Genetics, Medical University of Sofia, 2 Zdrave Str., Sofia 1431 (Bulgaria); Todinova, Svetla [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria); Gartcheva, Lidia [National Specialized Hospital for Active Treating of Haematological Diseases, 6 Plovdivsko pole Str., Sofia 1756 (Bulgaria); Milanova, Vihra [Department of Psychiatry, Medical University of Sofia, 1 Sv. Georgi Sofiiski Str., Sofia 1431 (Bulgaria); Toncheva, Draga [Department of Medical Genetics, Medical University of Sofia, 2 Zdrave Str., Sofia 1431 (Bulgaria); Taneva, Stefka G., E-mail: stefka.germanova@ehu.es [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria)
2013-11-20
Highlights: • DSC reveals modified thermal behavior of blood serum from schizophrenic patients. • The high-abundance portion of the serum proteome is thermally stabilized in Sz. • The Sz plasma thermograms are classified in four distinct calorimetric groups. • The effectiveness of drug treatment correlates with the plasma thermodynamic behavior. - Abstract: Schizophrenia (Sz) is a multifactorial mental disorder with high frequency. Due to its chronic and relapsing nature there is a strong need for biomarkers for early psychosis detection and objective evaluation of drug (usually antipsychotics) treatment effect. Here differential scanning calorimetry (DSC) is applied to thermodynamically characterize the blood serum proteome of paranoid schizophrenia patients on routine antipsychotic treatment in comparison to healthy controls. DSC revealed significant modifications in the thermodynamic behavior of blood sera from Sz patients, the overall thermal profile being changed in all Sz cases under study. The calorimetric profiles were classified in four distinct groups, reflecting different thermal stabilization of the high-abundance portion of the serum proteome. The observed positive (thermograms becoming closer to the healthy profile) or negative (thermograms deviating stronger from the healthy profile) proteome thermal stability switches and the Sz thermograms persistence in patients’ follow-up corresponded well with the effect of drug treatment.
Calorimetric monitoring of the serum proteome in schizophrenia patients
International Nuclear Information System (INIS)
Krumova, Sashka; Rukova, Blaga; Todinova, Svetla; Gartcheva, Lidia; Milanova, Vihra; Toncheva, Draga; Taneva, Stefka G.
2013-01-01
Highlights: • DSC reveals modified thermal behavior of blood serum from schizophrenic patients. • The high-abundance portion of the serum proteome is thermally stabilized in Sz. • The Sz plasma thermograms are classified in four distinct calorimetric groups. • The effectiveness of drug treatment correlates with the plasma thermodynamic behavior. - Abstract: Schizophrenia (Sz) is a multifactorial mental disorder with high frequency. Due to its chronic and relapsing nature there is a strong need for biomarkers for early psychosis detection and objective evaluation of drug (usually antipsychotics) treatment effect. Here differential scanning calorimetry (DSC) is applied to thermodynamically characterize the blood serum proteome of paranoid schizophrenia patients on routine antipsychotic treatment in comparison to healthy controls. DSC revealed significant modifications in the thermodynamic behavior of blood sera from Sz patients, the overall thermal profile being changed in all Sz cases under study. The calorimetric profiles were classified in four distinct groups, reflecting different thermal stabilization of the high-abundance portion of the serum proteome. The observed positive (thermograms becoming closer to the healthy profile) or negative (thermograms deviating stronger from the healthy profile) proteome thermal stability switches and the Sz thermograms persistence in patients’ follow-up corresponded well with the effect of drug treatment
Lee, Ae-Ri Cho; Moon, Hee Kyung
2007-11-01
A thermal gravimetric analysis (TGA) and a differential scanning calorimetry (DSC) were carried out to characterize the water property and an alteration of lipid phase transition of stratum corneum (SC) by glycerin. In addition, the relationship between steady state skin permeation rate and skin hydration in various concentrations of glycerin was investigated. Water vapor absorption-desorption was studied in the hairless mouse stratum corneum. Dry SC samples were exposed to different conc. of glycerin (0-50%) followed by exposure to dry air and the change in weight property was monitored over time by use of TGA. In DSC study, significant decrease in DeltaH of the lipid transition in 10% glycerin and water treated sample: the heat of lipid transition of normal, water, 10% glycerin treated SC were 6.058, 4.412 and 4.316 mJ/mg, respectively. In 10% glycerin treated SCs, the Tc of water shifts around 129 degrees C, corresponding to the weakly bound secondary water. In 40% glycerin treated SC, the Tc of water shifts to 144 degrees C corresponding to strongly bound primary water. There was a good correlation between the hydration property of the skin and the steady state skin flux with the correlation coefficient (r2=0.94). As the hydration increased, the steady state flux increased. As glycerin concentration increased, hydration property decreased. High diffusivity induced by the hydration effect of glycerin and water could be the major contributing factor for the enhanced skin permeation of nicotinic acid (NA).
Reading, Mike
2006-01-01
MTDSC provides a step-change increase in the power of calorimetry to characterize virtually all polymer systems including curing systems, blends and semicrystalline polymers. It enables hidden transitions to be revealed, miscibility to be accurately assessed, and phases and interfaces in complex blends to be quantified. It also enables crystallinity in complex systems to be measured and provides new insights into melting behaviour. All of this is achieved by a simple modification of conventional DSC. In 1992 a new calorimetric technique was introduced that superimposed a small modulation on top of the conventional linear temperature program typically used in differential scanning calorimetry. This was combined with a method of data analysis that enabled the sample’s response to the linear component of the temperature program to be separated from its response to the periodic component. In this way, for the first time, a signal equivalent to that of conventional DSC was obtained simultaneously with a measure ...
Althouse, L P
1979-01-01
Study of the aging processes in polyurethane adhesives using thermal treatment and differential calorimetric, dielectric, and mechanical techniques ; 1, identifying the aging processes ; 2, quantifying the aging effect
Marlowe, R. L.; Lukan, A. M.; Lee, S. A.; Anthony, L.; Rupprecht, A.
1996-03-01
Differential scanning calorimetry was used to measure the binding strength between calf-thymus DNA and its primary water of hydration. The specific heat of wet-spun films was found to have a broad endothermic transition near 80 ^oC and a sharp exothermic transition near 250 ^oC. The broad transition is believed to be mainly due to the breaking of the bonds of the strongly bound water of hydration. This transition was found to be reversible, as expected. Kissinger analysis indicates that the activation barrier for breaking the bonds of these water molecules is about 0.6 eV. The sharp transition appeared to be an indication of a thermal decomposition of the DNA. Samples taken above this transition lost mass, showed evidence of having melted, and had turned black in color. This transition is irreversible.
Directory of Open Access Journals (Sweden)
Erhan Süleymanoglu
2004-11-01
Full Text Available Complexes between nucleic acids and phospholipid vesicles have been developed as stable non-viral gene delivery vehicles. Currently employed approach uses positively charged lipid species and a helper zwitterionic lipid, the latter being applied for the stabilization of the whole complex. However, besides problematic steps during their preparation, cationic lipids are toxic for cells. The present work describes some energetic issues pertinent to preparation and use of neutral lipid-DNA self-assemblies, thus avoiding toxicity of lipoplexes. Differential scanning calorimetry data showed stabilization of polynucleotide helix upon its interaction with liposomes in the presence of divalent metal cations. It is thus possible to suggest this self-assembly as an improved formulation for use in gene delivery.
Polarized differential-phase laser scanning microscope
International Nuclear Information System (INIS)
Chou Chien; Lyu, C.-W.; Peng, L.-C.
2001-01-01
A polarized differential-phase laser scanning microscope, which combines a polarized optical heterodyne Mach-Zehnder interferometer and a differential amplifier to scan the topographic image of a surface, is proposed. In the experiment the differential amplifier, which acts as a PM-AM converter, in the experiment, converting phase modulation (PM) into amplitude modulation (AM). Then a novel, to our knowledge, phase demodulator was proposed and implemented for the differential-phase laser scanning microscope. An optical grating (1800 lp/mm) was imaged. The lateral and the depth resolutions of the imaging system were 0.5 μm and 1 nm, respectively. The detection accuracy, which was limited by the reflectivity variation of the test surface, is discussed
Kearns, Kenneth L; Swallen, Stephen F; Ediger, M D; Sun, Ye; Yu, Lian
2009-02-12
Indomethacin glasses of varying stabilities were prepared by physical vapor deposition onto substrates at 265 K. Enthalpy relaxation and the mobility onset temperature were assessed with differential scanning calorimetry (DSC). Quasi-isothermal temperature-modulated DSC was used to measure the reversing heat capacity during annealing above the glass transition temperature Tg. At deposition rates near 8 A/s, scanning DSC shows two enthalpy relaxation peaks and quasi-isothermal DSC shows a two-step change in the reversing heat capacity. We attribute these features to two distinct local packing structures in the vapor-deposited glass, and this interpretation is supported by the strong correlation between the two calorimetric signatures of the glass to liquid transformation. At lower deposition rates, a larger fraction of the sample is prepared in the more stable local packing. The transformation of the vapor-deposited glasses into the supercooled liquid above Tg is exceedingly slow, as much as 4500 times slower than the structural relaxation time of the liquid.
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ATUS BUKU
2017-02-01
Full Text Available The aim of this study is to identify the value of compounds contained in liquid coal by using Fourier Transform Infra-Red (FTIR and Differential Scanning Calorimeter (DSC. FTIR was used to analyse the components contained in liquid coal, while the DSC is done to observe the heat reaction to the environment. Based on the Fourier Transform Infra-Red (FTIR test results it is shown that the compound contained in the liquid Coal consisting of alkanes, alkenes and alkyne. These compounds are similar compounds. The alkanes, alkenes and alkynes compounds undergo complete combustion reaction with oxygen and would produce CO2 and water vapour [H2O (g]. If incomplete combustion occurs, the reaction proceeds in the form of Carbon Monoxide CO gas or solid carbon andH2O. Combustion reaction that occurs in all these three compounds also produces a number of considerable energy. And if it has higher value of Carbon then the boiling point would be higher. From the Differential Scanning Calorimetric (DSC test results obtained some of the factors that affect the reaction speed, which are the temperature, the reaction mixture composition, and pressure. Temperature has a profound influence in coal liquefaction, because if liquid coal heated with high pressure, the carbon chain would break down into smaller chains consisting of aromatic chain, hydro-aromatic, or aliphatic. This then triggers a reaction between oil formation and polymerization reactions to form solids (char.
The Calvet calorimetric dosimeter
International Nuclear Information System (INIS)
Puig, J.R.; Romano, F.
1965-01-01
This report describes a dosimeter based on the conduction calorimetry principle, and designed to operate in swimming-pool type nuclear reactors. The properties of the apparatus are as follows: 1 - the measurement is independent of the specific heat of the calorimetric elements; 2 - each calorimetric element is fitted with an electrical calibration; 3 - the apparatus is made up of two independent calorimetric elements; 4 - the nature of the calorimetric elements makes it possible to analyse the radiation received; 5 - the measurable intensities of the absorbed radiation vary from 4 to 4000 M/rads per hour; 6 - the sensitive part of the apparatus is fitted inside a cylinder 5 cm high and 2 cm in diameter. One pre-production unit made up of graphite and beryllium cores has been tried out in the reactor Siloe with radiation intensities of about 1 to 2 watts per gram. It absorbed an accumulated dose of 1.2*1O 12 rads without any weaknesses appearing. (authors) [fr
Davoodi, J.; Wakarchuk, W. W.; Surewicz, W. K.; Carey, P. R.
1998-01-01
The stabilities of Bacillus circulans xylanase and a disulfide-bridge-containing mutant (S100C/N148C) were investigated by differential scanning calorimetry (DSC) and thermal inactivation kinetics. The thermal denaturation of both proteins was found to be irreversible, and the apparent transition temperatures showed a considerable dependence upon scanning rate. In the presence of low (nondenaturing) concentrations of urea, calorimetric transitions were observed for both proteins in the second...
Investigation of phase transformations in ductile cast iron of differential scanning calorimetry
International Nuclear Information System (INIS)
Przeliorz, R; Piatkowski, J
2011-01-01
The effect of heating rate on phase transformations to austenite range in ductile cast iron of the EN-GJS-450-10 grade was investigated. For studies of phase transformations, the technique of differential scanning calorimetry (DSC) was used. Micro structure was examined by optical microscopy. The calorimetric examinations have proved that on heating three transformations occur in this grade of ductile iron, viz. magnetic transformation at the Curie temperature, pearlite→austenite transformation and ferrite→austenite transformation. An increase in the heating rate shifts the pearlite→austenite and ferrite→austenite transformations to higher temperature range. At the heating rate of 5 and 15 deg. C min -1 , local extrema have been observed to occur: for pearlite→austenite transformation at 784 deg. C and 795 deg. C, respectively, and for ferrite+ graphite →austenite transformation at 805 deg. C and 821 deg. C, respectively. The Curie temperature of magnetic transformation was extrapolated to a value of 740 deg. C. Each transformation is related with a specific thermal effect. The highest value of enthalpy is accompanying the ferrite→austenite transformation, the lowest occurs in the case of pearlite→austenite transformation.
Determinación de un polimorfo de la cimetidina mediante la calorimetría diferencial de barrido
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Luis Martínez Álvarez
1997-12-01
Full Text Available Se estableció la diferencia entre 2 sustancias de masa molecular similar -la cimetidina A y la B-, pero de estructuras internas distintas, mediante el empleo de la técnica de calorimetría diferencial de barrido donde solamente una de ellas, la cimetidina B, posee la actividad farmacológica requerida, es decir, cumple con las especificaciones de la farmacopea.The difference between two substances of similar mollecular mass but of different internal structuras -cimetidine A and B- was established by using the differential scanning calorimetry. It was proved that only one of them, cimetidine B, has the required pharmacological activity, which means that it fulfills the pharmacopoeia specifications.
Analyzing Protein Denaturation using Fast Differential Scanning Calorimetry
Splinter, R.; Van Herwaarden, A.W.; Iervolino, E.; Vanden Poel, G.; Istrate, D.; Sarro, P.M.
2012-01-01
This paper investigates the possibility to measure protein denaturation with Fast Differential Scanning Calorimetry (FDSC). Cancer can be diagnosed by measuring protein denaturation in blood plasma using Differential Scanning Calorimetry (DSC). FDSC can reduce diagnosis time from hours to minutes,
Calorimetric dosimetry of reactor radiation
International Nuclear Information System (INIS)
Radak, B.; Markovic, V.; Draganic, I.
1961-01-01
Calorimetric dosimetry of reactor radiation is relatively new reactor dosimetry method and the number of relevant papers is rather small. Some difficulties in applying standard methods (chemical dosemeters, ionization chambers) exist because of the complexity of radiation. In general application of calorimetric dosemeters for measuring absorbed doses is most precise. In addition to adequate choice of calorimetric bodies there is a possibility of determining the yields of each component of the radiation mixture in the total absorbed dose. This paper contains a short review of the basic calorimetry methods and some results of measurements at the RA reactor in Vinca performed by isothermal calorimeter [sr
Directory of Open Access Journals (Sweden)
R. Przeliorz
2010-04-01
Full Text Available The effect of heating rate on phase transformations to austenite range in ductile iron of the EN-GJS-450-10 grade was investigated. For studies of phase transformations, the technique of differential scanning calorimetry (DSC was used. Microstructure was examined by optical microscopy. The calorimetric examinations have proved that on heating three transformations occur in this grade of ductile iron, viz. magnetic transformation at the Curie temperature, pearlite→austenite transformation and ferrite→austenite transformation. An increase in the heating rate shifts the pearlite→austenite and ferrite→austenite transformations to higher temperature range. At the heating rate of 5 and 15°C/min, local extrema have been observed to occur: for pearlite→austenite transformation at 784°C and 795°C, respectively, and for ferrite→austenite transformation at 805°C and 821°C, respectively. The Curie temperature of magnetic transformation was extrapolated to a value of 740°C. Each transformation is related with a specific thermal effect. The highest value of enthalpy is accompanying the ferrite→austenite transformation, the lowest occurs in the case of pearlite→austenite transformation.
Energy Technology Data Exchange (ETDEWEB)
Missal, Wjatscheslaw, E-mail: wmissal@gmx.net [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany); Kita, Jaroslaw [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany); Wappler, Eberhard [wsk Mess- und Datentechnik GmbH, Gueterbahnhofstr. 1, 63450 Hanau (Germany); Bechtold, Franz [VIA electronic GmbH, Robert-Friese-Str. 3, 07629 Hermsdorf (Germany); Moos, Ralf [Department of Functional Materials, University of Bayreuth, 95440 Bayreuth (Germany)
2012-09-10
Highlights: Black-Right-Pointing-Pointer Unique vertical design of a DSC device manufactured in the low-cost LTCC technology and therefore capable of one-way use. Black-Right-Pointing-Pointer Fully functional DSC device with a size of only 1.5 mm Multiplication-Sign 11 mm Multiplication-Sign 39 mm enabling very low power consumption. Black-Right-Pointing-Pointer Comparable measurement performance as conventional DSC whilst also suitable for mobile thermal analysis. Black-Right-Pointing-Pointer Thermal resolution is 0.12 (TAWN test). Repeatability of the peak area is within 0.3% for indium samples. Black-Right-Pointing-Pointer Calorimetric sensitivity: linear with regard to temperature and independent from sample mass and heating rate in wide ranges. - Abstract: The calorimetric properties of a novel miniaturized ceramic differential scanning calorimeter device (MC-DSC) with integrated heater and crucible are presented. All features of a conventional DSC apparatus (including oven) are integrated into this DSC device of the size 11 mm Multiplication-Sign 39 mm Multiplication-Sign 1.5 mm. The MC-DSC device is suitable for one-way use, since it is fully manufactured in the low-cost planar low temperature co-fired ceramics technology. First characterization of this device is performed using indium, tin and zinc samples. The calorimetric sensitivity at 156.6 Degree-Sign C is 0.24 J/ Degree-Sign C s. It depends linearly on temperature in the range of at least 150 Degree-Sign C and 420 Degree-Sign C. The calorimetric sensitivity is constant up to an enthalpy of fusion of at least {Delta}H = 750 mJ (at 156.6 Degree-Sign C). The thermal analysis of indium in direct contact to the crucible of the chip even reveals a constant calorimetric sensitivity up to an enthalpy of fusion of at least {Delta}H = 1000 mJ. The repeatability of the peak area is within {+-}0.3% (11 mg indium, 10 measurements). The thermal resolution determined using 4,4 Prime -azoxyanisole under TAWN test
Phase transitions in the urea/n-nonadecane system by calorimetric techniques
International Nuclear Information System (INIS)
Lopez-Echarri, A; Ruiz-Larrea, I; Fraile-RodrIguez, A; Diaz-Hernandez, J; Breczewski, T; Bocanegra, E H
2007-01-01
A calorimetric study of urea/n-nonadecane, CO(NH 2 ) 2 /C 19 H 40 , and the deuterated derivatives, CO(ND 2 ) 2 /C 19 D 40 and CO(NH 2 ) 2 /C 19 D 40 , around the structural phase transition temperature is presented. For this purpose differential scanning (DSC), temperature-modulated (AC) and adiabatic calorimetry have been used and the obtained results are compared. Leaving apart the noticeable peak associated with the main phase transition at 158.5, 149.4 and 154 K respectively, small anomalies of the specific heat are found at lower temperatures and their corresponding entropic and enthalpic changes are reported. Heating and cooling experiments show the influence of the temperature rate and the thermal history on the detailed profile of the specific heat traces. The presence of thermal hysteresis and latent heat as a way to characterize the order of the phase transitions is discussed. Finally, a tentative approach to the urea and the alkyl chain contributions to the specific heat and their influence on the phase transition mechanisms is presented
Calorimetric features of IgM gammopathies. Implication for patient’s diagnosis and monitoring
Energy Technology Data Exchange (ETDEWEB)
Krumova, Sashka; Todinova, Svetla; Danailova, Avgustina [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 21, 1113 Sofia (Bulgaria); Petkova, Violeta; Dimitrova, Keranka; Gartcheva, Lidia [National Specialized Hospital for Active Treating of Haematological Diseases, Sofia 1756 (Bulgaria); Taneva, Stefka G., E-mail: stefka.germanova@ehu.es [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., bl. 21, 1113 Sofia (Bulgaria); Unidad de Biofísica (CSIC-UPV/EHU) and Departamento de Bioquímica y Biología Molecular, Universidad del País Vasco, 48080 Bilbao (Spain)
2015-09-10
Highlights: • DSC reveals distinct calorimetric features for IgM gammopaties. • Calorimetry sets of IgM multiple myeloma and Waldenström’s macroglobulinemia patients. • DSC features correlate with the level of involved IgM heavy/light chains. • DSC and “Heavylite” are complementary methods for patients diagnostics/monitoring. - Abstract: The serum proteome of patients featuring immunoglobulin M (IgM) gammopathy and diagnosed as having IgM multiple myeloma or Waldenström’s macroglobulinemia was characterized by differential scanning calorimetry and HevyLite™ (HLC) assay. The thermodynamic properties of the thermograms and their deviation from the typical healthy thermogram were found to correlate with the monoclonal protein concentration and the level of the involved (monoclonal) IgM heavy/light chains. Patients monitoring during treatment showed that the variations in the shape of the DSC profiles corresponded to fluctuations of the IgM heavy/light chain levels verifying the two parameters as non-invasive markers for disease progression.
International Nuclear Information System (INIS)
Almagor, M.; Cole, R.D.
1989-01-01
Nuclei from cultured human cells were examined by differential scanning calorimetry. Their melting profiles revealed four structural transitions at 60, 76, 88, and 105 degrees C (transitions I-IV, respectively). In immortalized (i.e., tumor) cell cultures and in normal cell cultures of low passage number, melting profiles were dominated by the 105 degrees C transition (transition IV), but in vitro aging of normal and Werner syndrome cells was associated with a marked decrease in transition IV followed by an increase in transition III at the expense of transition IV. At intermediate times in the aging process, much DNA melted at a temperature range (95-102 degrees C) intermediate between transitions III and IV, and this is consistent with the notion that aging of cell cultures is accompanied by an increase in single-strand character of the DNA. Calorimetric changes were observed in the melting profile of nuclei from UV-irradiated tumor cells that resembled the age-induced intermediate melting of chromatin. It is suggested that aging is accompanied by an increase in single-stranded character of the DNA in chromatin, which lowers its melting temperature, followed by strand breaks in the DNA that destroy its supercoiling potential
Method for HEPA filter leak scanning with differentiating aerosol detector
Energy Technology Data Exchange (ETDEWEB)
Kovach, B.J.; Banks, E.M.; Wikoff, W.O. [NUCON International, Inc., Columbus, OH (United States)
1997-08-01
While scanning HEPA filters for leaks with {open_quotes}Off the Shelf{close_quote} aerosol detection equipment, the operator`s scanning speed is limited by the time constant and threshold sensitivity of the detector. This is based on detection of the aerosol density, where the maximum signal is achieved when the scanning probe resides over the pinhole longer than several detector time-constants. Since the differential value of the changing signal can be determined by observing only the first small fraction of the rising signal, using a differentiating amplifier will speed up the locating process. The other advantage of differentiation is that slow signal drift or zero offset will not interfere with the process of locating the leak, since they are not detected. A scanning hand-probe attachable to any NUCON{reg_sign} Aerosol Detector displaying the combination of both aerosol density and differentiated signal was designed. 3 refs., 1 fig.
High-pressure differential scanning microcalorimeter.
Senin, A A; Dzhavadov, L N; Potekhin, S A
2016-03-01
A differential scanning microcalorimeter for studying thermotropic conformational transitions of biopolymers at high pressure has been designed. The calorimeter allows taking measurements of partial heat capacity of biopolymer solutions vs. temperature at pressures up to 3000 atm. The principles of operation of the device, methods of its calibration, as well as possible applications are discussed.
International Nuclear Information System (INIS)
Farkas, N.; Belagyi, J.; Lorinczy, D.
2003-01-01
Mild oxidation of -SH-containing proteins (serum albumin, hemoglobin) by Ce(IV)-ions in the presence of the spin trap phenyl-tert-butylnitrone (PBN) resulted in the appearance of strongly immobilized nitroxide free radicals which evidences the formation of thiyl radicals on the thiol site of the proteins. In hydroxyl free radical generating system a fraction of strongly immobilized nitroxide radicals was also detected in these proteins, which implies that the oxidation of a fraction of the thiol groups was also involved in the free radical reaction. According to the differential scanning calorimetry (DSC) experiments the melting processes of the proteins were calorimetrically irreversible, therefore the two-state kinetic model was used to evaluate the experiments. The results support the view that site-specific interaction of SH-containing proteins with hydroxyl and thiyl free radicals is able to modify the internal dynamics of proteins and affect the conformation of large molecules
A differential scanning calorimetric and X-ray diffraction
Indian Academy of Sciences (India)
X-ray diffraction analysis of the two groups demonstrated predominance of austenitic ... Discrete crystallographic structure and absence of multiple phases showed ... Division of Orthodontics, Indian Army, 10 Corps Dental Unit, C/O 56 APO, ...
Differential scanning calorimetric and powder X-ray diffraction ...
Indian Academy of Sciences (India)
18) ... cells with no nuclei and cell organelles.1 The main composition of the ... properties of these molecules in a systematic manner. Most useful in this .... 1630. D Sivaramakrishna and Musti J Swamy. 40. 50. 60. 70. 80. 90. 40. 50. 60. 70. 80. 90.
Evaluation of aluminosilicate glass sintering during differential scanning calorimetry
International Nuclear Information System (INIS)
Souza, Juliana Pereira de
2015-01-01
In this work a difference in the baseline in differential scanning calorimetry analyses, observed in a work where aluminosilicate glasses microspheres containing Ho were studied for application in selective internal radiotherapy as hepatocellular carcinoma treatment, was studied. The glasses with nominal composition 53,7 SiO 2 .10,5 Al 2 O 3 . 35,8 MgO in %mol were produced from traditional melting. The first obtained were milled and sieved in the range of 45 a 63 μm. The material was used to produce glass microspheres by the gravitational fall method. The glass powder and the microspheres were characterized by X ray fluorescence spectrometry, laser diffraction, X ray diffraction, differential scanning calorimetry, differential thermal analysis, thermogravimetry, mass spectrometry, and scanning electron microscopy. After the thermal analyses, pellets were formed in the crucibles and were analyzed by scanning electron microscopy, X ray diffraction, and He pycnometry. The difference in the baseline was associated to the viscous flow sintering process and happens because of the decrease in the detected heat flow due to the sample shrinkage. Other events as concurrent crystallization with the sintering process were also studied. (author)
Usefulness of Thallium Scan for Differential Diagnosis of Breast Mass
Energy Technology Data Exchange (ETDEWEB)
Bae, Sang Kyun; Yum, Ha Yong; Lee, Chung Han; Choi, Kyung Hyun [Kosin University College of Medicine, Pusan (Korea, Republic of)
1994-07-15
The purpose of this study is to evaluate thallium scanning as a potential test in differentiating malignant from benign lesions of breast. Thirty-one female patients underwent thallium scan of the breast. After intravenous injection of 74-111 MBq(2-3 mCi)of thallium-201, anterior and lateral images were obtained. We compared thallium scans with pathological results. Of 11 patients with breast cancers, 10 cases (90.9%) were detected using thallium scan. Thallium scan obtained in one patient who had breast cancer but received several cycles of chemotherapy did not show thallium uptake. The smallest detectable cancer was 1.5 cm in diameter. In contrast, there is no thallium accumulation in breasts of 17 of 20 patients with benign disease (85%), Three cases of 13 fibrocystic disease show thallium uptake in their breast. In conclusion, thallium scan is an effective test in differentiating benign from malignant lesion.
Usefulness of Thallium Scan for Differential Diagnosis of Breast Mass
International Nuclear Information System (INIS)
Bae, Sang Kyun; Yum, Ha Yong; Lee, Chung Han; Choi, Kyung Hyun
1994-01-01
The purpose of this study is to evaluate thallium scanning as a potential test in differentiating malignant from benign lesions of breast. Thirty-one female patients underwent thallium scan of the breast. After intravenous injection of 74-111 MBq(2-3 mCi)of thallium-201, anterior and lateral images were obtained. We compared thallium scans with pathological results. Of 11 patients with breast cancers, 10 cases (90.9%) were detected using thallium scan. Thallium scan obtained in one patient who had breast cancer but received several cycles of chemotherapy did not show thallium uptake. The smallest detectable cancer was 1.5 cm in diameter. In contrast, there is no thallium accumulation in breasts of 17 of 20 patients with benign disease (85%), Three cases of 13 fibrocystic disease show thallium uptake in their breast. In conclusion, thallium scan is an effective test in differentiating benign from malignant lesion.
Calibration models for high enthalpy calorimetric probes.
Kannel, A
1978-07-01
The accuracy of gas-aspirated liquid-cooled calorimetric probes used for measuring the enthalpy of high-temperature gas streams is studied. The error in the differential temperature measurements caused by internal and external heat transfer interactions is considered and quantified by mathematical models. The analysis suggests calibration methods for the evaluation of dimensionless heat transfer parameters in the models, which then can give a more accurate value for the enthalpy of the sample. Calibration models for four types of calorimeters are applied to results from the literature and from our own experiments: a circular slit calorimeter developed by the author, single-cooling jacket probe, double-cooling jacket probe, and split-flow cooling jacket probe. The results show that the models are useful for describing and correcting the temperature measurements.
Calorimetric signatures of human cancer cells and their nuclei
Energy Technology Data Exchange (ETDEWEB)
Todinova, S. [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria); Stoyanova, E. [Department of Molecular Immunology, Institute of Biology and Immunology of Reproduction, Bulgarian Academy of Sciences, Tzarigradsko shose Blvd. 73, Sofia 1113 (Bulgaria); Krumova, S., E-mail: sakrumo@gmail.com [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria); Iliev, I. [Institute of Experimental Morphology, Pathology and Anthropology with Museum, Acad. G. Bonchev Str., Bl. 25, Sofia 1113 (Bulgaria); Taneva, S.G. [Institute of Biophysics and Biomedical Engineering, Bulgarian Academy of Sciences, Acad. G. Bonchev Str., Bl. 21, Sofia 1113 (Bulgaria)
2016-01-10
Graphical abstract: - Highlights: • Two temperature ranges are distinguished in the thermograms of cells/nuclei. • Different thermodynamic properties of cancer and normal human cells/nuclei. • Dramatic reduction of the enthalpy of the low-temperature range in cancer cells. • Oxaliplatin and 5-FU affect the nuclear matrix proteins and the DNA stability. - Abstract: The human cancer cell lines HeLa, JEG-3, Hep G2, SSC-9, PC-3, HT-29, MCF7 and their isolated nuclei were characterized by differential scanning calorimetry. The calorimetric profiles differed from normal human fibroblast (BJ) cells in the two well distinguished temperature ranges—the high-temperature range (H{sub T}, due to DNA-containing structures) and the low-temperature range (L{sub T}, assigned to the nuclear matrix and cellular proteins). The enthalpy of the L{sub T} range, and, respectively the ratio of the enthalpies of the L{sub T}- vs. H{sub T}-range, ΔH{sub L}/ΔH{sub H}, is strongly reduced for all cancer cells compared to normal fibroblasts. On the contrary, for most of the cancer nuclei this ratio is higher compared to normal nuclei. The HT-29 human colorectal cancer cells/nuclei differed most drastically from normal human fibroblast cells/nuclei. Our data also reveal that the treatment of HT-29 cancer cells with cytostatic drugs affects not only the DNA replication but also the cellular proteome.
Thallium 201 thyroid scan: differential diagnosis of benign and malignant nodules
International Nuclear Information System (INIS)
Oh, Jong Sub; Kim, Byong Geun; Park, Byung Ran; Kim, Se Jong; Ko, Kang Seok; Kim, Min Joong; Ji, Joo Yun
1995-01-01
To evaluate useful findings and diagnostic value of TI-201 thyroid scan in differentiating benign from malignant nodules. We studied 77 cold thyroid nodules proven histologically(27 malignant and 50 benign). Early (5-15 min) and delayed images(3-5 hours) were obtained after intravenous injection of thallium 201. In these nodules, we retrospectively analyzed the degree of TI-201 uptake in early and delayed images, histopathologic type, size, and presence or absence of cystic change in the sonograms of 22 malignant nodules. Useful finding for diagnosis of malignant nodules was strong uptake of TI-201 in early and delayed images(specificity: 98%, sensitivity: 63%, positive predictive value: 94.4%). Useful finding for benign nodules was no uptake of TI-201 in delayed image(specificity: 88.9%, sensitivity: 68%, positive predictive value: 91.9%). The accuracy of TI-201 thyroid scan in differentiating benign from malignant nodules was 66.2%. The nodules with strong TI-201 uptake in early image and low TI-201 uptake in delayed image were malignant in 29.4%. Cystic changes were found in 40% of malignant nodules with atypical TI-201 uptake. TI-201 thyroid scan showed high specificity in follicular neoplasm and adenomatous goiter in which differentiation of benignancy and malignancy is difficult with only cytologic examination. We consider that TI-201 thyroid scan is valuable in differentiating benign from malignant nodules and when combined with fine needle aspiration and ultrasound examination, it will enable more accurate differential diagnosis between benign and malignant thyroid nodules
Calorimetric and relaxation properties of xylitol-water mixtures
Elamin, Khalid; Sjöström, Johan; Jansson, Helén; Swenson, Jan
2012-03-01
We present the first broadband dielectric spectroscopy (BDS) and differential scanning calorimetry study of supercooled xylitol-water mixtures in the whole concentration range and in wide frequency (10-2-106 Hz) and temperature (120-365 K) ranges. The calorimetric glass transition, Tg, decreases from 247 K for pure xylitol to about 181 K at a water concentration of approximately 37 wt. %. At water concentrations in the range 29-35 wt. % a plentiful calorimetric behaviour is observed. In addition to the glass transition, almost simultaneous crystallization and melting events occurring around 230-240 K. At higher water concentrations ice is formed during cooling and the glass transition temperature increases to a steady value of about 200 K for all higher water concentrations. This Tg corresponds to an unfrozen xylitol-water solution containing 20 wt. % water. In addition to the true glass transition we also observed a glass transition-like feature at 220 K for all the ice containing samples. However, this feature is more likely due to ice dissolution [A. Inaba and O. Andersson, Thermochim. Acta, 461, 44 (2007)]. In the case of the BDS measurements the presence of water clearly has an effect on both the cooperative α-relaxation and the secondary β-relaxation. The α-relaxation shows a non-Arrhenius temperature dependence and becomes faster with increasing concentration of water. The fragility of the solutions, determined by the temperature dependence of the α-relaxation close to the dynamic glass transition, decreases with increasing water content up to about 26 wt. % water, where ice starts to form. This decrease in fragility with increasing water content is most likely caused by the increasing density of hydrogen bonds, forming a network-like structure in the deeply supercooled regime. The intensity of the secondary β-relaxation of xylitol decreases noticeably already at a water content of 2 wt. %, and at a water content above 5 wt. % it has been replaced by a
Differential scanning microcalorimetry of intrinsically disordered proteins.
Permyakov, Sergei E
2012-01-01
Ultrasensitive differential scanning calorimetry (DSC) is an indispensable thermophysical technique enabling to get direct information on enthalpies accompanying heating/cooling of dilute biopolymer solutions. The thermal dependence of protein heat capacity extracted from DSC data is a valuable source of information on intrinsic disorder level of a protein. Application details and limitations of DSC technique in exploration of protein intrinsic disorder are described.
Energy Technology Data Exchange (ETDEWEB)
Mostafa, Mohamed; Vali, Reza; Chan, Jeffrey; Omarkhail, Yusuaf; Shammas, Amer [University of Toronto, Nuclear Medicine Division, Department of Medical Imaging, The Hospital for Sick Children, Toronto, Ontario (Canada)
2016-10-15
Potentially false-positive findings on radioiodine scans in children with differentiated thyroid carcinoma can mimic functioning thyroid tissue and functioning thyroid carcinomatous tissue. Such false-positive findings comprise variants and pitfalls that can vary slightly in children as compared with adults. To determine the patterns and frequency of these potential false-positive findings on radioiodine scans in children with differentiated thyroid carcinoma. We reviewed a total of 223 radioiodine scans from 53 pediatric patients (mean age 13.3 years, 37 girls) with differentiated thyroid carcinoma. Focal or regional activity that likely did not represent functioning thyroid tissue or functioning thyroid carcinomatous tissue were categorized as variants or pitfalls. The final diagnosis was confirmed by reviewing the concurrent and follow-up clinical data, correlative ultrasonography, CT scanning, serum thyroglobulin and antithyroglobulin antibody levels. We calculated the frequency of these variants and pitfalls from diagnostic and post-therapy radioiodine scans. The most common variant on the radioiodine scans was the thymic activity (24/223, 10.8%) followed by the cardiac activity (8/223, 3.6%). Salivary contamination and star artifact, caused by prominent thyroid remnant, were the most important observed pitfalls. Variants and pitfalls that mimic functioning thyroid tissue or functioning thyroid carcinomatous tissue on radioiodine scan in children with differentiated thyroid carcinoma are not infrequent, but they decrease in frequency on successive radioiodine scans. Potential false-positive findings can be minimized with proper knowledge of the common variants and pitfalls in children and correlation with clinical, laboratory and imaging data. (orig.)
[Significance and mechanism of MSCT perfusion scan on differentiation of NSCLC].
Liu, Jin-Kang; Hu, Cheng-Ping; Zhou, Mo-Ling; Zhou, Hui; Xiong, Zeng; Xia, Yu; Chen, Wei
2009-06-01
To determine the significance of MSCT perfusion scan on differentiation of NSCLC and to investigate its possible mechanisms. Forty four NSCLC patients underwent CT perfusion scan by MSCT. Among them, 22 cases were selected to detected the two-dimensional tumor microvascular architecture phenotype (2D-TMAP), the relationships between CT perfusion parameters (BF, BV, PEI, TIP), and the differentiation of NSCLC were analysed by using the correlation analysis and trend test. Spearman correlation analysis was used to study the relationships between CT perfusion parameters, differentiation, and 2D-TMAP. The total BF, BV and PEI decreased with decreasing differentiation of NSCLC (P<0.05). The total PEI showed a positive correlation with the total MVD (P<0.05). There were negative correlations between the surrounding area BF, the total BF, BV, and PEI, the uncomplete lumen of the surrounding area MVD, and expression of PCNA, respectively (P<0.05). There were positive correlations between degree of differentiation and the uncomplete lumen of the surrounding area MVD (P<0.05). It was the same as degree of differentiation and expression of PCNA, VEGF, respectively. There were positive correlations between the uncomplete lumen of the surrounding area MVD and expression of VEGF, ephrinB2, EphB4, and PCNA, respectively (P<0.05). Perfusion parameters reflect the difference of density of vassels with mature functional lumen. Careful evaluation of the differences of blood flow pattern in pulmonary space-occupying lesions by MSCT perfusion scan can be used to identify the degree of NSCLC differentiation.
International Nuclear Information System (INIS)
Mickols, W.; Maestre, M.F.
1988-01-01
A differential polarization microscope that couples the sensitivity of single-beam measurement of circular dichroism and circular differential scattering with the simultaneous measurement of linear dichroism and linear differential scattering has been developed. The microscope uses a scanning microscope stage and single-point illumination to give the very shallow depth of field found in confocal microscopy. This microscope can operate in the confocal mode as well as in the near confocal condition that can allow one to program the coherence and spatial resolution of the microscope. This microscope has been used to study the change in the structure of chromatin during the development of sperm in Drosophila
Design of Test Wrapper Scan Chain Based on Differential Evolution
Directory of Open Access Journals (Sweden)
Aijun Zhu
2013-08-01
Full Text Available Integrated Circuit has entered the era of design of the IP-based SoC (System on Chip, which makes the IP core reuse become a key issue. SoC test wrapper design for scan chain is a NP Hard problem, we propose an algorithm based on Differential Evolution (DE to design wrapper scan chain. Through group’s mutation, crossover and selection operations, the design of test wrapper scan chain is achieved. Experimental verification is carried out according to the international standard benchmark ITC’02. The results show that the algorithm can obtain shorter longest wrapper scan chains, compared with other algorithms.
Fast differential scanning calorimetry of liquid samples with chips
DEFF Research Database (Denmark)
Splinter, R.; van Herwaarden, A. W.; van Wetten, I. A.
2015-01-01
Based on a modified version of standard chips for fast differential scanning calorimetry, DSC of liquid samples has been performed at temperature scan rates of up to 1000 °C/s. This paper describes experimental results with the protein lysozyme, bovine serum, and olive oil. The heating and cooling....... The bovine serum measurements show two main peaks, in good agreement with standard DSC measurements. Olive oil has been measured, with good agreement for the cooling curve and qualitative agreement for the heater curve, compared to DSC measurements....
Differential scanning fluorimetry illuminates silk feedstock stability and processability
Czech Academy of Sciences Publication Activity Database
Dicko, C.; Kasoju, Naresh; Hawkins, N.; Vollrath, F.
2016-01-01
Roč. 12, č. 1 (2016), s. 255-262 ISSN 1744-683X R&D Projects: GA MŠk(CZ) EE2.3.30.0029 Institutional support: RVO:61389013 Keywords : differential scanning fluorimetry * biomaterials * silk fibroin Subject RIV: CE - Biochemistry Impact factor: 3.889, year: 2016
Energy Technology Data Exchange (ETDEWEB)
Cho, Ihn Ho; Won, Kyu Jang; Lee, Hyung Woo; Lee, Soon Jung [College of Medicine, Yonsei Univ., Seoul (Korea, Republic of)
1999-02-01
We performed this study to compare Tl-201 and Tc-99m MIBI scans for the differentiation of malignant from benign breast mass. Thirty-eight female patients underwent Tl-201 breast scan and thirty-two of them also underwent Tc-99m MIBI scan of the breast. After intravenous injection of 74-111 MBq of Tl-201, early (10 minutes) and delayed (3 hours) images were obtained. Then, 555-740 MBq of Tc-99m MIBI was injected and images after 30 minutes were obtained. We compared Tl-201 and Tc-99m MIBI scans with pathologic results. Twenty-three patients were confirmed to have infiltrating duct carcinoma and fifteen patients to have benign breast mass by excisonal biopsy. The sensitivity of early and delayed Tl-201 scan and Tc-99m MIBI scan in the detection of malignant breast lesion were 100% (23/23), 82% (18/22), and 90% (18/20), respectively. The sensitivity of early Tl-201 scan was significantly higher than that of delayed Tl-201 scan, (p<0.05). The specificity of early and delayed Tl-201 scan and Tc-99m MIBI scan were 73% (11/15), 73% (11/15) and 83% (10/12), respectively (p: not significant). Three patients out of nine with fibroadenoma and one patient with atypical duct hyperplasia were false positive in both early and delayed Tl-201 scans. The size of fibroadenoma with false positive in early and delayed Tl-201 scan (4 cases) was larger than that of 11 fibroadenoma with true negative scan (p<0.01). Metastatic axillary lymph node involvement was present in fifteen patients. The sensitivity to detect metastatic nodes was 38% (5/13) for early Tl-201 images, 15% (2/13) for delayed Tl-201 images, 58% (7/12) for Tc-99m MIBI planar images and 67% (4/6) for Tc-99m MIBI SPECT. The sensitivity of Tc-99m MIBI planar or SPECT was significantly higher than that of delayed Tl-201 images (p<0.05). Early Tl-201 and Tc-99m MIBI scan are useful noninvasive methods to differentiate malignant from benign mass of breast. Tc-99m MIBI scan was sensitive in detecting axillary lymph node
Selection of non-destructive assay methods: Neutron counting or calorimetric assay?
International Nuclear Information System (INIS)
Cremers, T.L.; Wachter, J.R.
1994-01-01
The transition of DOE facilities from production to D ampersand D has lead to more measurements of product, waste, scrap, and other less attractive materials. Some of these materials are difficult to analyze by either neutron counting or calorimetric assay. To determine the most efficacious analysis method, variety of materials, impure salts and hydrofluorination residues have been assayed by both calorimetric assay and neutron counting. New data will be presented together with a review of published data. The precision and accuracy of these measurements are compared to chemistry values and are reported. The contribution of the gamma ray isotopic determination measurement to the overall error of the calorimetric assay or neutron assay is examined and discussed. Other factors affecting selection of the most appropriate non-destructive assay method are listed and considered
Russo, Giacomo; Witos, Joanna; Rantamäki, Antti H; Wiedmer, Susanne K
2017-12-01
The present work aims at studying the interactions between cholesterol-rich phosphatidylcholine-based lipid vesicles and trioctylmethylphosphonium acetate ([P 8881 ][OAc]), a biomass dissolving ionic liquid (IL). The effect of cholesterol was assayed by using differential scanning calorimetry (DSC) and nanoplasmonic sensing (NPS) measurement techniques. Cholesterol-enriched dipalmitoyl-phosphatidylcholine vesicles were exposed to different concentrations of the IL, and the derived membrane perturbation was monitored by DSC. The calorimetric data could suggest that the binding and infiltration of the IL are delayed in the vesicles containing cholesterol. To clarify our findings, NPS was applied to quantitatively follow the resistance of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine incorporating 0, 10, and 50mol% of cholesterol toward the IL exposure over time. The membrane perturbation induced by different concentrations of IL was found to be a concentration dependent process on cholesterol-free lipid vesicles. Moreover, our results showed that lipid depletion in cholesterol-enriched lipid vesicles is inversely proportional to the increasing amount of cholesterol in the vesicles. These findings support that cholesterol-rich lipid bilayers are less susceptible toward membrane disrupting agents as compared to membranes that do not incorporate any sterols. This probably occurs because cholesterol tightens the phospholipid acyl chain packing of the plasma membranes, increasing their resistance and reducing their permeability. Copyright © 2017 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Van Humbeeck, J.; Planes, A.
1996-01-01
Experimentally, two distinct classes of martensitic transformations are considered: athermal and isothermal. In the former class, on cooling, at some well-defined start temperature (M s ), isolated small regions of the martensitic product begin to appear in the parent phase. The transformation at any temperature appears to be instantaneous in practical time scales, and the amount of transformed material (x) does not depend on time, i.e., it increases at each step of lowering temperature. The transition is not completed until the temperature is lowered below M f (martensite finish temperature). The transformation temperatures are only determined by chemical (composition and degree of order) and microstructural factors. The external controlling parameter (T or applied stress) determines the free energy difference between the high and the low temperature phases, which provides the driving force for the transition. In the development of athermal martensite activation kinetics is secondary. Athermal martensite, as observed in the well known shape memory alloys Cu-Zn-Al, Cu-Al-Ni and Ni-Ti, cannot be attributed to a thermally activated mechanism for which kinetics are generally described by the Arrhenius rate equation. However, the latter has been applied by Lipe and Morris to results for the Martensitic Transformation of Cu-Al-Ni-B-Mn obtained by conventional Differential Scanning Calorimetry (DSC). It is the concern of the authors of this letter to point out the incongruences arising from the analysis of calorimetric results, corresponding to forward and reverse thermoelastic martensitic transformations, in terms of standard kinetic analysis based on the Arrhenius rate equation
Calorimetric dosimetry of reactor radiation; Kalorimetriska dozimetrija reaktorskog zracenja
Energy Technology Data Exchange (ETDEWEB)
Radak, B; Markovic, V; Draganic, I [Institute of Nuclear Sciences Boris Kidric, Odeljenje za radijacionu hemiju, Vinca, Beograd (Serbia and Montenegro)
1961-12-15
Calorimetric dosimetry of reactor radiation is relatively new reactor dosimetry method and the number of relevant papers is rather small. Some difficulties in applying standard methods (chemical dosemeters, ionization chambers) exist because of the complexity of radiation. In general application of calorimetric dosemeters for measuring absorbed doses is most precise. In addition to adequate choice of calorimetric bodies there is a possibility of determining the yields of each component of the radiation mixture in the total absorbed dose. This paper contains a short review of the basic calorimetry methods and some results of measurements at the RA reactor in Vinca performed by isothermal calorimeter. Kalorimetrijska dozimetrija reaktorskog zracenja je relativno nova metoda dozimetrije reaktora i broj do sada objavljenih radova je vrlo skroman. S obzirom na slozenu prirodu zracenja postoje neke teskoce pri radu sa standardnim metodama (hemijski dozimetri, jonizacione komere). U principu, upotreba kalorimetra za merenje apsorbovanih doza je najegzaktnija. Osim toga, uz pogodni izbor kalorimetrijskih tela postoji mogucnost za odredjivanje doprinosa pojedinih komponenti smese zracenja u totalnoj apsorbovanoj dozi. U tekstu je dat kratak pregled osnovnih metoda kalorimetrije i neki rezultati merenja sa izotermskim kalorimetrom na reaktoru RA u Vinci.
Differential scanning calorimetry techniques: applications in biology and nanoscience.
Gill, Pooria; Moghadam, Tahereh Tohidi; Ranjbar, Bijan
2010-12-01
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.
Differential Scanning Calorimetry Techniques: Applications in Biology and Nanoscience
Gill, Pooria; Moghadam, Tahereh Tohidi; Ranjbar, Bijan
2010-01-01
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.
Brewer, J M; Wampler, J E
2001-03-14
The thermal denaturation of yeast enolase 1 was studied by differential scanning calorimetry (DSC) under conditions of subunit association/dissociation, enzymatic activity or substrate binding without turnover and substrate analogue binding. Subunit association stabilizes the enzyme, that is, the enzyme dissociates before denaturing. The conformational change produced by conformational metal ion binding increases thermal stability by reducing subunit dissociation. 'Substrate' or analogue binding additionally stabilizes the enzyme, irrespective of whether turnover is occurring, perhaps in part by the same mechanism. More strongly bound metal ions also stabilize the enzyme more, which we interpret as consistent with metal ion loss before denaturation, though possibly the denaturation pathway is different in the absence of metal ion. We suggest that some of the stabilization by 'substrate' and analogue binding is owing to the closure of moveable polypeptide loops about the active site, producing a more 'closed' and hence thermostable conformation.
Differential scanning calorimetry of bacteria.
Miles, C A; Mackey, B M; Parsons, S E
1986-04-01
Thermograms obtained by differential scanning calorimetry of a range of bacteria of different heat resistances were compared. Equations were derived to calculate the rate at which the numbers of viable organisms in a calorimeter decline as the temperature is raised at a constant rate. Vegetative bacteria scanned at 10 degrees C min-1 showed multi-peaked thermograms with four major peaks (denoted m, n, p and q) occurring in the regions 68-73, 77-84, 89-99 and 105-110 degrees C respectively. Exceptions were that peak m (the largest peak) occurred at 79-82 degrees C in Bacillus stearothermophilus and an additional peak, r, was detected in Escherichia coli at 119 degrees C. At temperatures below the main peak m there were major differences in thermograms between species. There was a direct relationship between the onset of thermal denaturation and the thermoresistance of different organisms. Heat-sensitive organisms displayed thermogram features which were absent in the more heat-resistant types. When samples were cooled to 5 degrees C and re-heated, a small endothermic peak, pr, was observed at the same temperature as p. Peaks p and pr were identified as the melting endotherms of DNA. In all vegetative organisms examined, maximum death rates, computed from published D and z values, occurred at temperatures above the onset of thermal denaturation, i.e. cell death and irreversible denaturation of cell components occurred within the same temperature range.
International Nuclear Information System (INIS)
Chi, Jen-Hao; Wu, Sheng-Hung; Shu, Chi-Min
2009-01-01
In the past, process incidents attributed to organic peroxides (OPs) that involved near misses, over-pressures, runaway reactions, and thermal explosions occurred because of poor training, human error, incorrect kinetic assumptions, insufficient change management, and inadequate chemical knowledge in the manufacturing process. Calorimetric applications were employed broadly to test organic peroxides on a small-scale because of their thermal hazards, such as exothermic behavior and self-accelerating decomposition in the laboratory. In essence, methyl ethyl ketone peroxide (MEKPO) is highly reactive and exothermically unstable. In recent years, it has undergone many thermal explosions and runaway reaction incidents in the manufacturing process. Differential scanning calorimetry (DSC), vent sizing package 2 (VSP2), and thermal activity monitor (TAM) were employed to analyze thermokinetic parameters and safety index. The intent of the analyses was to facilitate the use of various auto-alarm equipments to detect over-pressure, over-temperature, and hazardous materials leaks for a wide spectrum of operations. Results indicated that MEKPO decomposition is detected at low temperatures (30-40 deg. C), and the rate of decomposition was shown to exponentially increase with temperature and pressure. Determining time to maximum rate (TMR), self-accelerating decomposition temperature (SADT), maximum temperature (T max ), exothermic onset temperature (T 0 ), and heat of decomposition (ΔH d ) was essential for identifying early-stage runaway reactions effectively for industries.
Physicochemical characterization of pitches by differential scanning calorimetry
Energy Technology Data Exchange (ETDEWEB)
Lahaye, J.; Ehrburger, P.; Saint-Romain, J.L.; Couderc, P.
1987-11-01
The glass transition characterization of pitches has been studied by differential scanning calorimetry (d.s.c.). Experimental results and theoretical considerations indicate that: (1) the average molecular mass of pitches can be characterized by the apparent activation energy of the relaxation phenomenon of pitch molecules; (2) the molecular polydispersity is correlated with the width of the glass transition. Characterization of pitch by d.s.c. is well adapted to follow pitch transformation during heat treatment. 6 refs., 6 figs., 4 tabs.
Temperature dependent Raman spectroscopy (TDR) applies the temperature gradients utilized in differential scanning calorimetry (DSC) to Raman spectroscopy, providing a straightforward technique to identify molecular rearrangements that occur just prior to phase transitions. Herein we apply TDR and D...
Accounting for apparent deviations between calorimetric and van't Hoff enthalpies.
Kantonen, Samuel A; Henriksen, Niel M; Gilson, Michael K
2018-03-01
In theory, binding enthalpies directly obtained from calorimetry (such as ITC) and the temperature dependence of the binding free energy (van't Hoff method) should agree. However, previous studies have often found them to be discrepant. Experimental binding enthalpies (both calorimetric and van't Hoff) are obtained for two host-guest pairs using ITC, and the discrepancy between the two enthalpies is examined. Modeling of artificial ITC data is also used to examine how different sources of error propagate to both types of binding enthalpies. For the host-guest pairs examined here, good agreement, to within about 0.4kcal/mol, is obtained between the two enthalpies. Additionally, using artificial data, we find that different sources of error propagate to either enthalpy uniquely, with concentration error and heat error propagating primarily to calorimetric and van't Hoff enthalpies, respectively. With modern calorimeters, good agreement between van't Hoff and calorimetric enthalpies should be achievable, barring issues due to non-ideality or unanticipated measurement pathologies. Indeed, disagreement between the two can serve as a flag for error-prone datasets. A review of the underlying theory supports the expectation that these two quantities should be in agreement. We address and arguably resolve long-standing questions regarding the relationship between calorimetric and van't Hoff enthalpies. In addition, we show that comparison of these two quantities can be used as an internal consistency check of a calorimetry study. Copyright © 2017 Elsevier B.V. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Barba de la Rosa, A.P.; Paredes-Lopez, O.; Carabez-Trejo, A.; Ordorica-Falomir, C. (Instituto Politecnico Nacional, Irapuato (Mexico). Centro de Investigacion y de Estudios Avanzados)
1989-11-01
High-protein amaranth flour (HPAF) and carbohydrate rich fraction (CRF) were produced from raw flour in a single-step process using a heat-stable alpha-amylase preparation. Protein content of flour increased from 15 to about 30 or 39% at liquefaction temperatures of 70 or 90{sup 0}C, respectively and 30 min hydrolysis time. CRF exhibited 14-22 DE. Enzymatic action at 70{sup 0}C increased endotherm temperature and gelatinization enthalpy of HPAF, in relation to gelatinized flour, as assessed by differential scanning calorimetry (DSC). Hydrolysis at 90{sup 0}C did not affect significantly (P > 0.05) DSC peak temperature. It is suggested that these changes in DSC performance might result from differences in amount and type of low-molecular weight carbohydrates and residual starch. Scanning electron microscopy (SEM) demonstrated that hydrolysis temperature changed substantially the structural appearance of flour particles. HPAF and CRF might find applications as dry milk extender and sweetener, respectively. (orig.).
Differential Aging Signals in Abdominal CT Scans.
Orlov, Nikita V; Makrogiannis, Sokratis; Ferrucci, Luigi; Goldberg, Ilya G
2017-12-01
Changes in the composition of body tissues are major aging phenotypes, but they have been difficult to study in depth. Here we describe age-related change in abdominal tissues observable in computed tomography (CT) scans. We used pattern recognition and machine learning to detect and quantify these changes in a model-agnostic fashion. CT scans of abdominal L4 sections were obtained from Baltimore Longitudinal Study of Aging (BLSA) participants. Age-related change in the constituent tissues were determined by training machine classifiers to differentiate age groups within male and female strata ("Younger" at 50-70 years old vs "Older" at 80-99 years old). The accuracy achieved by the classifiers in differentiating the age cohorts was used as a surrogate measure of the aging signal in the different tissues. The highest accuracy for discriminating age differences was 0.76 and 0.72 for males and females, respectively. The classification accuracy was 0.79 and 0.71 for adipose tissue, 0.70 and 0.68 for soft tissue, and 0.65 and 0.64 for bone. Using image data from a large sample of well-characterized pool of participants dispersed over a wide age range, we explored age-related differences in gross morphology and texture of abdominal tissues. This technology is advantageous for tracking effects of biological aging and predicting adverse outcomes when compared to the traditional use of specific molecular biomarkers. Application of pattern recognition and machine learning as a tool for analyzing medical images may provide much needed insight into tissue changes occurring with aging and, further, connect these changes with their metabolic and functional consequences. Published by Elsevier Inc.
Review of MEMS differential scanning calorimetry for biomolecular study
Yu, Shifeng; Wang, Shuyu; Lu, Ming; Zuo, Lei
2017-12-01
Differential scanning calorimetry (DSC) is one of the few techniques that allow direct determination of enthalpy values for binding reactions and conformational transitions in biomolecules. It provides the thermodynamics information of the biomolecules which consists of Gibbs free energy, enthalpy and entropy in a straightforward manner that enables deep understanding of the structure function relationship in biomolecules such as the folding/unfolding of protein and DNA, and ligand bindings. This review provides an up to date overview of the applications of DSC in biomolecular study such as the bovine serum albumin denaturation study, the relationship between the melting point of lysozyme and the scanning rate. We also introduce the recent advances of the development of micro-electro-mechanic-system (MEMS) based DSCs.
Toyran, Neslihan; Severcan, Feride
2007-08-01
Magnesium (Mg 2+) ion is of great importance in physiology by its intervention in 300 enzymatic systems, its role in membrane structure, its function in neuromuscular excitability and vitamin D metabolism and/or action. In the present study, the interaction of Mg 2+, at low (1 mole %) and high (7 mole %) concentrations with dipalmitoyl phosphatidylcholine (DPPC) liposomes has been studied in the presence and absence of vitamin D 2 (1 mole %) by using two noninvasive techniques, namely differential scanning calorimetry (DSC) and Fourier transform infrared (FTIR) spectroscopy. DSC studies reveal that the presence of vitamin D 2 in the pure or Mg 2+ (at both low and high concentrations) containing liposomes diminishes the pretransition. The calorimetric results also reveal that, inclusion of Mg 2+ (more significantly at high concentration) into pure or vitamin D 2 containing DPPC liposomes increases the main phase transition temperature. The investigation of the CH 2 symmetric, the CH 3 asymmetric, the C dbnd O stretching, and the PO2- antisymmetric double bond stretching bands in FTIR spectra with respect to changes occurring in the wavenumber and/or the bandwidth values as a function of temperature reveal that, inclusion of vitamin D 2 or Mg 2+ into pure DPPC liposomes orders and decreases the dynamics of the acyl chains in both gel and liquid-crystalline phases and does not induce hydrogen bond formation in the interfacial region. Furthermore, the dynamics of the head groups of the liposomes decreases in both phases. Our findings reveal that, simultaneous presence of vitamin D 2 and Mg 2+ alters the effect of each other, which is reflected as a decrease in the interactions between these two additives within the model membrane.
Measurement of ion energy by a calorimetric method
Energy Technology Data Exchange (ETDEWEB)
Mizuhashi, Kiyoshi; Tajima, Satoshi [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Bunak, Suwat
1996-12-01
In calorimetric method, ion energy is determined based on the temperature changes during radiation of an absorbing material, radiation current and heat capacity of the calorimeter. This method is convenient and its measuring procedures are simple as well as the measuring apparatus. Here, the temperature changes of the calorimeter during {sup 14}N ion beam radiation were determined. The temperature increased linearly when irradiated with {sup 14}N{sup 3+}, 8.3 MeV or {sup 14}N{sup 2+}, 6 MeV, but not linearly for {sup 14}N{sup 1+}, 3.6 MeV, resulting in a comparatively large error. Thus, the measurement of ion energy by calorimetric method was found available as a convenient method for an accelerator having an energy stability less than 10{sup -3}. Especially this method seems to be useful for low-energy ion accelerator or ion injecting apparatus. (M.N.)
Some examples of the estimation of error for calorimetric assay of plutonium-bearing solids
International Nuclear Information System (INIS)
Rodenburg, W.W.
1977-04-01
This report provides numerical examples of error estimation and related measurement assurance programs for the calorimetric assay of plutonium. It is primarily intended for users who do not consider themselves experts in the field of calorimetry. These examples will provide practical and useful information in establishing a calorimetric assay capability which fulfills regulatory requirements. 10 tables, 5 figures
Calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid
International Nuclear Information System (INIS)
Kurbanov, A.R.; Sharipov, D.Sh.
1993-01-01
Present article is devoted to calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid. The calorimetric study of interaction of barium hydroxide with diluted solutions of hydrofluoric acid was carried out in order to determine the thermal effects of reactions. The results of interaction of Ba(OH) 4 ·8H 2 O with 5, 10, and 20% solution of hydrofluoric acid were considered.
Calorimetric measurements of $^{163}$ holmium decay as tools to determine the electron neutrino mass
De Rújula, Alvaro
1982-01-01
Computes the spectrum of 'calorimetric' energy in the electron capture decay of /sup 163/Ho. A calorimetric experiment would yield an excellent determination of (/sup 163/Ho, /sup 163/Dy) mass difference. The proximity of the spectral endpoint to an atomic resonance makes the fraction of events that are sensitive to a non-zero neutrino mass superior in /sup 163/Ho decay than in tritium decay.
Calorimetric dosimetry in neutron and charged particle beams
International Nuclear Information System (INIS)
McDonald, J.C.; Ma, I.C.; Laughlin, J.S.
1978-01-01
A portable tissue-equivalent (TE) calorimetric, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in several neutron radiotherapy fields. Comparisons of spherical, cylindrical, and thimble shaped TE ionization chambers have been carried out using either air, or a flow of TE gas in the chamber
Differential phase microscope and micro-tomography with a Foucault knife-edge scanning filter
Watanabe, N.; Hashizume, J.; Goto, M.; Yamaguchi, M.; Tsujimura, T.; Aoki, S.
2013-10-01
An x-ray differential phase microscope with a Foucault knife-edge scanning filter was set up at the bending magnet source BL3C, Photon Factory. A reconstructed phase profile from the differential phase image of an aluminium wire at 5.36 keV was fairly good agreement with the numerical simulation. Phase tomography of a biological specimen, such as an Artemia cyst, could be successfully demonstrated.
Characterization of pitches by differential scanning calorimetry
Energy Technology Data Exchange (ETDEWEB)
Ehrburger, P.; Martin, C.; Lahaye, J.; Saint-Romain, J.L.; Couderc, P.
1988-12-01
Pitch materials have generally a very complex composition with molecular mass ranging from a few hundred to several thousands units. In order to characterize these materials their properties related to the glassy transformation, in particular to enthalpy relaxation, have been investigated. Solvent soluble fractions have been characterized by differential scanning calorimetry (DSC). As with polymeric materials, enthalpy relaxation can provide information about pitches and the interactions occurring between the different types of molecules present in the pitch: mean molecular size, structural factor, molecular-size distribution. The determination of glass transition properties provides a useful means for the characterization of pitch and of their solvent extracts. It also permits insight into the complex reactions which occur when pitch materials are heat-treated. 7 refs., 2 figs., 3 tabs.
Menéndez, M; Gasset, M; Laynez, J; López-Zumel, C; Usobiaga, P; Töpfer-Petersen, E; Calvete, J J
1995-12-15
The CUB domain is a widespread 110-amino-acid module found in functionally diverse, often developmentally regulated proteins, for which an antiparallel beta-barrel topology similar to that in immunoglobulin V domains has been predicted. Spermadhesins have been proposed as a subgroup of this protein family built up by a single CUB domain architecture. To test the proposed structural model, we have analyzed the structural organization of two members of the spermadhesin protein family, porcine seminal plasma proteins I/II (PSP-I/PSP-II) heterodimer and bovine acidic seminal fluid protein (aSFP) homodimer, using differential scanning calorimetry, far-ultraviolet circular dichroism and Fourier-transform infrared spectroscopy. Thermal unfolding of PSP-I/PSP-II and aSFP were irreversible and followed a one-step process with transition temperatures (Tm) of 60.5 degrees C and 78.6 degrees C, respectively. The calorimetric enthalpy changes (delta Hcat) of thermal denaturation were 439 kJ/mol for PSP-I/PSP-II and 660 kJ/mol for aSFP dimer. Analysis of the calorimetric curves of PSP-I/PSP-II showed that the entire dimer constituted the cooperative unfolding unit. Fourier-transform infrared spectroscopy and deconvolution of circular dichroic spectra using a convex constraint analysis indicated that beta-structure and turns are the major structural element of both PSP-I/PSP-II (53% of beta-sheet, 21% of turns) and aSFP (44% of beta-sheet, 36% of turns), and that the porcine and the bovine proteins contain little, if any, alpha-helical structure. Taken together, our results indicate that the porcine and the bovine spermadhesin molecules are probably all-beta-structure proteins, and would support a beta-barrel topology like that predicted for the CUB domain. Other beta-structure folds, such as the Greek-key pattern characteristic of many carbohydrate-binding protein domains cannot be eliminated. Finally, the same combination of biophysical techniques was used to characterize the
Calorimetric method for current sharing temperature measurements in ITER conductor samples in SULTAN
International Nuclear Information System (INIS)
Bagnasco, M.
2009-01-01
Several Toroidal Field Conductor short samples with slight layout variations have been assembled and tested in the SULTAN facility at CRPP. The measurement campaigns started in 2007 and are still ongoing. The performance of every conductor is expressed in terms of current sharing temperature (T cs ), i.e. the temperature at which a defined electric field, 10 μV/m, is detected in the cable due to the incipient superconducting-to-normal state transition. The T cs at specific operating conditions is the key design parameter for the ITER conductors and is the main object of the qualification tests. Typically, the average electric field is measured with voltage tap pairs attached on the jacket along the conductor. The inability however to explain observed premature voltage developments opened the discussion about possible alternative measuring methods. The He flow calorimetric method is based on the measurement of the resistive power generation in the conductor. It relies on the detection of very small temperature increases along the conductor in steady state operation. The accuracy and the reliability of the calorimetric method in SULTAN are critically discussed, with particular emphasis on the instrumentation requirements and test procedures. The application of the calorimetric method to the recent SULTAN test campaigns is described with its merits and limits. For future tests of ITER conductors in SULTAN, the calorimetric method for T cs test is proposed as a routine procedure.
Shen, Jiacheng; Igathinathane, C; Yu, Manlu; Pothula, Anand Kumar
2015-06-01
Integral reaction heats of switchgrass, big bluestem, and corn stalks were determined using thermogravimetric analysis/differential scanning calorimetry (TGA/DSC). Iso-conversion differential reaction heats using TGA/DSC pyrolysis and combustion of biomass were not available, despite reports available on heats required and released. A concept of iso-conversion differential reaction heats was used to determine the differential reaction heats of each thermal characteristics segment of these materials. Results showed that the integral reaction heats were endothermic from 30 to 700°C for pyrolysis of switchgrass and big bluestem, but they were exothermic for corn stalks prior to 587°C. However, the integral reaction heats for combustion of the materials followed an endothermic to exothermic transition. The differential reaction heats of switchgrass pyrolysis were predominantly endothermic in the fraction of mass loss (0.0536-0.975), and were exothermic for corn stalks (0.0885-0.850) and big bluestem (0.736-0.919). Study results provided better insight into biomass thermal mechanism. Published by Elsevier Ltd.
Study of gamma irradiated polyethylenes by temperature modulated differential scanning calorimetry
International Nuclear Information System (INIS)
Secerov, B.; Galovic, S.; Trifunovic, S.; Milicevic, D.; Suljovrujic, E.
2011-01-01
Complete text of publication follows. The various polyethylenes (PEs) and effects of high energy radiation on theirs structures were widely studied in the past using conventional Differential Scanning Calorimetry (DSC) measurements. In this work, we applied the Temperature Modulated Differential Scanning Calorimetry (TMDSC) technique in order to obtain more information about the influence of initial structural differences and gamma radiation on the evolution in structure and thermal properties of different polyethylenes. For this reason, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) samples were exposed to gamma radiation, in air, to a wide range of absorbed doses (up to 2400 kGy). The separation of the total heat flow TMDSC signal into a reversing and nonreversing part enabled to observed the low temperature enthalpy relaxation (related to the existence of the 'rigid amorphous phase') and recrystallization processes as well as to follow their and/or radiation-induced evolution of melting in a more revealing manner compared to the case of the conventional DSC. Consequently, our results indicate that TMDSC could improve the understanding of radiation-induced effects in polymers.
Uchida, Takeyoshi; Kikuchi, Tsuneo
2013-07-01
Ultrasonic power is one of the key quantities closely related to the safety of medical ultrasonic equipment. An ultrasonic power standard is required for establishment of safety. Generally, an ultrasonic power standard below approximately 20 W is established by the radiation force balance (RFB) method as the most accurate measurement method. However, RFB is not suitable for high ultrasonic power because of thermal damage to the absorbing target. Consequently, an alternative method to RFB is required. We have been developing a measurement technique for high ultrasonic power by the calorimetric method. In this study, we examined the effect of heat generation of an ultrasound transducer on ultrasonic power measured by the calorimetric method. As a result, an excessively high ultrasonic power was measured owing to the effect of heat generation from internal loss in the transducer. A reference ultrasound transducer with low heat generation is required for a high ultrasonic power standard established by the calorimetric method.
Energy Technology Data Exchange (ETDEWEB)
Bonjour, E; Pierre, J; Agagliate, S; Bertrand, P; Faivre, J; Lagnier, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires, Section physico-chimie et basses temperatures
1967-06-01
A differential calorimetric device of original design is described. Its allows direct measurements of thermal effects (adsorption or release) during a linear rise of temperature. The self compensated power method which is applied by means of a very sensitive control system, gives a direct value of the different heat capacity between the sample and a dummy of it. The detection threshold is about {+-} 100 micro-watts to {+-} 250 micro-watts. Applications: - Generally measurements of enthalpy changes of massive or powdered samples. - Measurement of Wigner energy after low temperature irradiation (77 deg. K). - Measurements of energy release in low temperature (77 deg. K) cold worked metals. (authors) [French] On decrit un dispositif de calorimetrie differentielle, de conception originale, qui permet de mesurer directement des effets thermiques en absorption ou en degagement de chaleur, au cours d'une montee en temperature lineaire. La methode de compensation automatique de puissance qui est mise en oeuvre au moyen de cha es d'asservissement tres sensibles, conduit a une determination directe de la capacite calorifique differencielle entre l'echantillon et sa reference. Le seuil de detection est de l'ordre de {+-} 100 a {+-} 250 microwatts. Applications: - D'une facon generale, mesure des variations enthalpiques, sur echantillons massifs ou en poudre. - Mesure de l'energie Wigner apres irradiation a basse temperature (77 deg. K). - Mesure de l'energie restauree apres deformation des metaux a basse temperature (77 deg. K). (auteurs)
Thermodynamic consistency of vapor pressure and calorimetric data for argon, krypton, and xenon
International Nuclear Information System (INIS)
Schwalbe, L.A.; Crawford, R.K.; Chen, H.H.; Aziz, R.A.
1977-01-01
A new two-parameter vapor pressure equation has been derived which, unlike the Salter equation, is shown to be equally applicable to quantum or classical solids and even liquids. The condensed phase enthalpies and entropies are given directly by the fitted parameters with accuracies comparable to those which have been claimed for existing independent calorimetric measurements. Recent vapor pressure data for the solid and liquid phases of argon, krypton, and xenon are analyzed in this manner, and the results are compared with the available calorimetric data. New values for the cohesive energy at T=0 are also derived for these substances
Determination of the protonation enthalpy of humic acid by calorimetric titration technique
International Nuclear Information System (INIS)
Kimuro, Shingo; Kirishima, Akira; Sato, Nobuaki
2015-01-01
Graphical abstract: The thermodynamic quantities of protonation of humic acid were determined by the combination of potentiometric titration and calorimetric titration. It was observed that the protonation enthalpy and Gibbs free energy had been affected by pH of solution. As a result, the thermodynamics of the protonation reaction of humic acid is influenced by the polyelectrolyte effect and the heterogeneity. - Highlights: • We applied calorimetric titration technique to the protonation of humic acid. • The thermodynamic quantities of protonation of humic acid were determined. • The protonation enthalpy of humic acid is affected by the heterogeneity. • Gibbs free energy of the protonation is affected by the polyelectrolyte effect. - Abstract: In this study, the calorimetric titration technique was used to determine the protonation enthalpy of two reference humic acids and polyacrylic acid. First, we obtained the apparent protonation constant of two kinds of humic acid purchased from IHSS (International Humic Substances Society) and polyacrylic acid by potentiometric titration. Second, we obtained the protonation enthalpy of them by calorimetric titration. The protonation enthalpy of humic acid was affected by pH and the ionic strength of bulk solution. From the comparison of ΔH between humic acid and polyacrylic acid, it was concluded that the pH dependence of ΔH is attributed to the heterogeneity of humic acid. And ΔH of phenolic hydroxyl group in humic acid is strongly influenced by the electric double layer of humic acid’s surface. This is considered to be a reason of the ionic strength dependence of ΔH. On the other hand, Gibbs free energy of the protonation of humic acid is affected by the electrostatic attraction with the progress of dissociation of functional groups such as carboxyl group and phenolic hydroxyl group. Consequently, the thermodynamics of the protonation of humic acid is affected by the polyelectrolyte effect and the
Whitson, K. B.; Marlowe, R. L.; Lukan, A. M.; Lee, S. A.; Anthony, L.; Rupprecht, A.
1997-11-01
DSC was performed on samples of K-hyaluronate (KHA) through a temperature range of 25-180^oC. A transition peak was observed which is due to the desorption of the primary water of hydration. The maximum position of the peak was observed to change with different scan rates. The average energy of activation, E_A, and enthalpy for desorption of the primary water of hydration was determined to be 0.62 and 0.17 eV per water molecule, respectively. Analysis of Mossbauer data(G. Albanese et al., Hyperfine Int.,) 95, 97 (1995) allowed us to determine the effective force constant, k_eff, of the water bound to KHA to be approximately 19.4 eV/nm^2. The parameters E_A, ΔH,and k_eff allow us to construct a potential model for the primary water of hydration of KHA. Comparison of these parameters with the same parameters for HA and DNA with different counterions reveal that the energy of activation is similar, as well as the enthalpy change.
Amos, W B; Reichelt, S; Cattermole, D M; Laufer, J
2003-05-01
In this paper, differential phase imaging (DPC) with transmitted light is implemented by adding a suitable detection system to a standard commercially available scanning confocal microscope. DPC, a long-established method in scanning optical microscopy, depends on detecting the intensity difference between opposite halves or quadrants of a split photodiode detector placed in an aperture plane. Here, DPC is compared with scanned differential interference contrast (DIC) using a variety of biological specimens and objective lenses of high numerical aperture. While DPC and DIC images are generally similar, DPC seems to have a greater depth of field. DPC has several advantages over DIC. These include low cost (no polarizing or strain-free optics are required), absence of a double scanning spot, electronically variable direction of shading and the ability to image specimens in plastic dishes where birefringence prevents the use of DIC. DPC is also here found to need 20 times less laser power at the specimen than DIC.
Lindane Suppresses the Lipid-bilayer Permeability in Main Transition Region
DEFF Research Database (Denmark)
Sabra, Mads Christian; Jørgensen, Kent; Mouritsen, Ole G.
1996-01-01
The effects of a small molecule, the insecticide lindane, on unilamellar DMPC bilayers in the phase transition region, have been studied by means of differential scanning calorimetry and fluorescence spectroscopy. The calorimetric data show that increasing concentrations of lindane broaden the tr...
First Calorimetric Measurement of OI-line in the Electron Capture Spectrum of $^{163}$Ho
Ranitzsch, P. C. -O.; Wegner, M.; Kempf, S.; Fleischmann, A.; Enss, C.; Gastaldo, L.; Herlert, A.; Johnston, K.
2014-01-01
The isotope $^{163}$Ho undergoes an electron capture process with a recommended value for the energy available to the decay, $Q_{\\rm EC}$, of about 2.5 keV. According to the present knowledge, this is the lowest $Q_{\\rm EC}$ value for electron capture processes. Because of that, $^{163}$Ho is the best candidate to perform experiments to investigate the value of the electron neutrino mass based on the analysis of the calorimetrically measured spectrum. We present for the first time the calorimetric measurement of the atomic de-excitation of the $^{163}$Dy daughter atom upon the capture of an electron from the 5s shell in $^{163}$Ho, OI-line. The measured peak energy is 48 eV. This measurement was performed using low temperature metallic magnetic calorimeters with the $^{163}$Ho ion implanted in the absorber. We demonstrate that the calorimetric spectrum of $^{163}$Ho can be measured with high precision and that the parameters describing the spectrum can be learned from the analysis of the data. Finally, we dis...
Calorimetric cryodetectors for heavy ions
Energy Technology Data Exchange (ETDEWEB)
Egelhof, P; Henning, W; Kienlin, A v; Meier, J; Truebenbacher, V [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany, F.R.) Mainz Univ. (Germany, F.R.). Inst. fuer Physik; Azgui, F [CDTN, Algiers (Algeria); Shepard, K [Argonne National Lab., IL (USA)
1990-01-01
Status and first test results are reported for a project to develop calorimetric cryodetectors for heavy ions. The special conditions for the detection of energetic heavy ions are discussed. Presently the investigations are focussed on semiconductor bolometers and aluminium-strip superconducting phase-transition thermometers that are cooled with liquid {sup 4}He and operate in the temperature range 1.3-4.2 K. For a germanium bolometer the temperature dependence of the resistance, voltage-current curves, the time response to heating by voltage pulses and the response to ionizing {alpha}-radiation are reported. First tests on phase transition thermometers using thin aluminum strips yield a transition width of {Delta}T=8.6 mK at T{sub c}=1.467 K. (orig.).
An autosampling differential scanning calorimeter instrument for studying molecular interactions.
Plotnikov, Valerian; Rochalski, Andrew; Brandts, Michael; Brandts, John F; Williston, Samuel; Frasca, Verna; Lin, Lung-Nan
2002-11-01
A new ultrasensitive differential scanning calorimeter (DSC) instrument is described, which utilizes autosampling for continuous operation. High scanning rates to 250 deg/h with rapid cooling and equilibration between scans facilitates higher sample throughput up to 50 samples during each 24 h of unattended operation. The instrument is suited for those pharmaceutical applications where higher throughput is important, such as screening drug candidates for binding constant or screening solution conditions for stability of liquid protein formulations. Results are presented on the binding of five different anionic inhibitors to ribonuclease A, which included cytidine 2'-monophosphate (2'CMP), 3'CMP, uridine 3'-monophosphate, pyrophosphate, and phosphate. Binding constants K(B) (or dissociation constants K(d)) are obtained from the shift in the transition temperature T(M) for ribonuclease thermal unfolding in the presence of ligand relative to the transition temperature in the absence of ligand. Measured binding constants ranged from 155 M(-1) (K(d) = 6.45 mM) for the weak-binding phosphate anion to 13100 M(-1) (K(d) = 76.3 microM) for the strongest binding ligand, 2'CMP. The DSC method for measuring binding constants can also be extended to ultratight interactions involving either ligand-protein or protein-protein binding.
Calorimetric analysis of photopolymerization
International Nuclear Information System (INIS)
Hoyle, C.E.
1992-01-01
This review is divided into several sections. The first section establishes the basis for measurement of the heat evolution during polymerization by focusing on the chemical chain process that results in the exothermic production of heat. The second section describes the types of photocalorimeters and the methods and instrumentation involved in exothermic measurements. Considerable attention is given to the use of the differential scanning calorimeter to record the exothermic curves generated by photopolymerization of monofunctional and multifunctional monomers. The final section presents a thorough coverage of the results obtained by a large number of research groups using photocalorimetric measurements to provide a more accurate description of polymerization processes. 120 refs., 51 figs., 14 tabs
A study of gamma-irradiated polyethylenes by temperature modulated differential scanning calorimetry
Galovic, S.; Secerov, B.; Trifunovic, S.; Milicevic, D.; Suljovrujic, E.
2012-09-01
Various polyethylenes (PEs) and the effects of high-energy radiation on their structures were widely studied in the past using conventional Differential Scanning Calorimetry (DSC) measurements. In this work, we used the Temperature Modulated Differential Scanning Calorimetry (TMDSC) technique in order to obtain more information about the influence of the initial structural differences and gamma radiation on the evolution in structure and thermal properties of different polyethylenes. For this reason, low density polyethylene (LDPE), linear low density polyethylene (LLDPE) and high density polyethylene (HDPE) samples were exposed to gamma radiation, in air, to a wide range of absorbed doses (up to 2400 kGy). The separation of the total heat flow TMDSC signal into a reversing and non-reversing part enabled us to observe the low-temperature enthalpy relaxation (related to the existence of the "rigid amorphous phase") and recrystallisation processes, as well as to follow their radiation-induced evolution and/or that of melting in a more revealing manner compared to the case of the conventional DSC. Consequently, our results indicate that TMDSC could improve the understanding of radiation-induced effects in polymers.
International Nuclear Information System (INIS)
Phan, T.T.H.; Tol, K.M. van; Links, T.P.; Piers, D.A.; Vries, E.G.E. de; Dullaart, R.P.F.; Jager, P.L.
2004-01-01
After initial treatment with total thyroidectomy and radio iodine ablation, most follow-up protocols for patients with differentiated thyroid carcinoma contain cyclic diagnostic I-131 imaging and serum thyroglobulin (Tg) measurements. The applied diagnostic I-131 doses vary between 37 and 370 MBq. The aim of this study was to determine the yield of a diagnostic scan with 370 MBq I-131 in patients with a negative diagnostic scan with 74 MBq I-131. Retrospective evaluation of 158 patients who received a high-dose diagnostic scan with 370 MBq I-131 because of a negative low-dose diagnostic scan with 74 MBq I-131. Special attention was paid to the patients with positive high-dose diagnostic scanning and undetectable serum Tg levels after thyroid hormone withdrawal. In 127 (80%) of patients the 370 MBq I-131 scan was negative, just like the preceding low-dose scan. In 31 (20%) of patients abnormal uptake was present on the 370 MBq diagnostic scan. In 19 of these 31 patients serum Tg was undetectable. In 15/19 the high-dose diagnostic scan proved either false positive or demonstrated clinically irrelevant minor ablation rests. In only four patients (2.5%) did the high-dose diagnostic scans reveal possibly relevant uptake caused by residual differentiated thyroid cancer. In 98% of patients a 370 MBq dose of I-131 for diagnostic whole-body scintigraphy (WBS) had no additional value. The combination of a low-dose diagnostic I-131 scan using only 74 MBq combined with a serum Tg level measurement proved sufficient for correct clinical decision making regarding whether the patient requires additional I-131 therapy. (authors)
Heilbron, M.A.; Gellings, P.J.
1976-01-01
Thermogravimetry (TG) of A(H2O)6BX6 complexes are presented, with A = Cd2+, Co2+, Cu2+, Fe2+, Mg2+, Mn2+, Ni2+, Pb2+, Zn2+, B=Si4+, Sn4+, Ti4+, Zr4+, and X=Cl−, F−. On a selected number of complexes, differential thermal analyses (DTA) and differential scanning calorimetric measurements (DSC) have
Reactivity of Monolayer Protected Silver Clusters Towards Excess Ligand: A Calorimetric Study
Baksi, Ananya; Bootharaju, Megalamane Siddaramappa; Chhotaray, Pratap K.; Chakraborty, Papri; Mondal, Biswajit; Bhat, Shridevi; Gardas, Ramesh L.; Pradeep, Thalappil
2017-01-01
Reactivity of monolayer protected atomically precise clusters of noble metals is of significant research interest. Till date very few experimental data are available on the reaction thermodynamics of such clusters. Here we report a calorimetric
International Nuclear Information System (INIS)
Seidel, J.; Pinkrah, V.T.; Mitchell, J.C.; Chowdhry, B.Z.; Snowden, M.J.
2004-01-01
Isothermal titration calorimetry (ITC) and potentiometric titration were used to study the protonation properties of the 4-vinylpyridine (4-VP) moiety in cationic poly(N-isopropylacrylamide-co-4-vinylpyridine) colloidal microgels [poly(NIPAM-co-4-VP)]. Calorimetric pH titrations were performed using microgels of different 4-VP content and the influence of ionic strength and counter ions have been examined. The calorimetric titration output consists of several thermal contributions reflecting the complex nature of the interactions in the aqueous microgel dispersions. In contrast to the potentiometric results, the calorimetric titration data could not be completely described by a theoretical model solely taking into account protonation equilibria. Deviations from the proposed model correlate with swelling or shrinking of the gel particles. The calorimetric results also reveal a pronounced counter-ion effect of perchlorate compared to chloride ions. In the presence of perchlorate ions, small secondary thermal effects accompany protonation of the 4-VP moiety due, in part, to kinetically limited conformational changes in the co-polymer microgel
International Nuclear Information System (INIS)
Agostinetti, P.; Palma, M. Dalla; Fantini, F.; Fellin, F.; Pasqualotto, R.
2011-01-01
The analytical interpretative models for calorimetric measurements currently available in the literature can consider close systems in steady-state and transient conditions, or open systems but only in steady-state conditions. The PCCE code (Predictive Code for Calorimetric Estimations), here presented, introduces some novelties. In fact, it can simulate with an analytical approach both the heated component and the cooling circuit, evaluating the heat fluxes due to conductive and convective processes both in steady-state and transient conditions. The main goal of this code is to model heating and cooling processes in actively cooled components of fusion experiments affected by high pulsed power loads, that are not easily analyzed with purely numerical approaches (like Finite Element Method or Computational Fluid Dynamics). A dedicated mathematical formulation, based on concentrated parameters, has been developed and is here described in detail. After a comparison and benchmark with the ANSYS commercial code, the PCCE code is applied to predict the calorimetric parameters in simple scenarios of the SPIDER experiment.
Detection of sunflower oil in extra virgin olive oil by fast differential scanning calorimetry
Wetten, I.A.; Herwaarden, A.W.; Splinter, R.; Boerrigter-Eenling, R.; Ruth, van S.M.
2015-01-01
Extra virgin olive oil (EVOO) is an economically valuable product, due to its high quality and premium price. Therefore it is vulnerable for adulteration by means of the addition of cheaper vegetable oils. Differential scanning calorimetry (DSC) has been suggested as a fast technique for the
Specific heat capacities of different clayey samples obtained by differential scanning calorimetry
International Nuclear Information System (INIS)
Fernandez, A.M.
2012-01-01
Document available in extended abstract form only. The thermo-physical properties allow to calculate heat flows and to determine the thermal behaviour of the materials. Temperature influences the rates of the physical, chemical and biological reactions and processes in the soil or a material. Variations in temperature and water content in thermal, hydraulic, mechanical and geochemical processes affect the thermal properties such as density, specific heat, thermal conductivity and thermal diffusivity. Therefore, mathematical models that describe the dependence of the thermal properties on temperature and concentration are of interest to be used in computational programs applied to the modelling of coupled thermo-mechanical-hydraulic and chemical (THMC) processes. In this work, the specific heat capacity of different clayey international reference materials was determined. Differential Scanning Calorimetry (DSC) was used for such purpose. DSC is the main tool for determining the specific heat capacities of materials as a function of temperature. The specific heat capacity, c p (J/Kg.K), is a measurement of the amount of heat required to raise the temperature of a unit mass of a substance by one unit of temperature. A change in temperature, caused by a gain or a loss of heat from a material, depends on the specific heat capacity of the material. Thus, the specific heat capacity is a key and characteristic property of a material and/or substance, which should be determine accurately. The specific heat capacity is an intensive property and, unlike the thermal conductivity and thermal diffusivity, is independent of the dry density of the material. C p of the solid samples was determined by using a SETSYS Evolution 16 thermal analyser coupled to a differential scanning calorimeter (TG-DSC-DTA) from SETARAM Instrumentation. The thermal analyser system can use a heating rate from 0.01 to 100 C/min under a dynamic argon atmosphere and temperatures ranging from ambient to
CONSTRUCTION OF A DIFFERENTIAL ISOTHERMAL CALORIMETER OF HIGH SENSITIVITY AND LOW COST.
Trinca, RB; Perles, CE; Volpe, PLO
2009-01-01
CONSTRUCTION OF A DIFFERENTIAL ISOTHERMAL CALORIMETER OF HIGH SENSITIVITY AND LOW COST The high cost of sensitivity commercial calorimeters may represent an obstacle for many calorimetric research groups. This work describes (fie construction and calibration of a batch differential heat conduction calorimeter with sample cells volumes of about 400 mu L. The calorimeter was built using two small high sensibility square Peltier thermoelectric sensors and the total cost was estimated to be about...
Standardization of 3H, 14C and 63Ni radiation sources by calorimetric method
International Nuclear Information System (INIS)
Khol'nova, E.A.; Kul'kova, L.P.
1979-01-01
The calorimetric method of determination of activity of radionuclides 3 H, 14 C and 63 Ni with low mean energies of β-particles has, as compare to other methods which had been used for determination of activity of these nuclides, a number of advantages, because a nuclide to be measured can be introduced into the calorimeter in any physical and chemical state. It is not necessary to distroy integrity ane leek-proofness of a source wnich can be of arbitrary type. There is no correction for absorption and self-absorption of β-particles and measuring instruments are relatively simple. As a limitation of this method is it's low sensitivity which can be owercomed by means of application of modern high sensitivity calorimeters. Such calorimeters have been developed in the Mendeleev All-Union research Institute. The calorimetric installation consists of 3 independent β-calorimeters of differential-double type, working in the regime of heat equilibrium and beeng intended for different by sise and shape sources. Then, there are thermostatting device of special desighn and electric measuring device. Number of thermocouples in each calorimeter is from 75 to 120 and sensitivity of calorimeters is from 2.45x10 -7 to 4.5x10 -7 Bt/mm depending on the type of calorimeter. Calorimeters are intended for measuring activities from 10 9 to 10 12 Bk. Error of measurement of activities equals 0.8-1.5% (with confidence level of 0.99%). The main portion of error consists of error in the medium energy β-spectra. The calorimeter error itself is much more lower. Soueces, which have been measured in the calorimeter than can be used for preparation of solutions and sources of lower activity [ru
Comparison and qualification of FFTF calorimetric methods
International Nuclear Information System (INIS)
McCall, T.B.; Nutt, W.T.; Zimmerman, B.D.
1981-01-01
The Fast Flux Test Facility achieved full power operation on December 21, 1981. During the power ascent, the reactor thermal power (calorimetric) was computed by three methods as follows: the plant main data handling computer, Plant Data System (PDS); a second computer, the Experimenter's Data System (EDS); and a manual method requiring human operator activities and a programmable calculator. It is the purpose of this paper to explain the rationale for employing the three methods, describe how each works in a schematic fashion, compare the results, and demonstrate that all methods have met stringent goals based on a statistical analysis of the results
Bodzewski, Kentaro Y.; Caylor, Ryan L.; Comstock, Ashley M.; Hadley, Austin T.; Imholt, Felisha M.; Kirwan, Kory D.; Oyama, Kira S.; Wise, Matthew E.
2016-01-01
A differential scanning calorimeter was used to study homogeneous nucleation of ice from micron-sized aqueous ammonium sulfate aerosol particles. It is important to understand the conditions at which these particles nucleate ice because of their connection to cirrus cloud formation. Additionally, the concept of freezing point depression, a topic…
Kiewiet, S; Janssens, V; Miltner, H. E; Van Assche, Gert; Van Puyvelde, Peter; Van Mele, B
2008-01-01
A newly developed hyphenated technique is presented combining an existing rheometer and differential scanning calorimeter into a single experimental setup. Through the development of a fixation accessory for differential scanning calorimeter (DSC) crucibles and a novel rotor, the simultaneous measurement is performed inside the well-controlled thermal environment of a Tzero (TM) DSC cell. Hence, the evolution of thermal and flow properties of a material can be simultaneously measured using st...
Calorimetric thermal-vacuum performance characterization of the BAe 80K space cryocooler
International Nuclear Information System (INIS)
Kotsubo, V.Y.; Johnson, D.L.; Ross, R.G. Jr.
1992-01-01
This paper on a comprehensive characterization program which is underway at JPL to generate test data on long-life, miniature Stirling-cycle cryocoolers for space application. The key focus of this paper is on the thermal performance of the British Aerospace (BAe) 80K split-Stirling-cycle cryocooler as measured in a unique calorimetric thermal-vacuum test chamber that accurately simulates the heat-transfer interfaces of space. Two separate cooling fluid loops provide precis individual control of the compressor and displacer heatsink temperatures. In addition, heatflow transducers enable calorimetric measurements of the heat rejected separately by the compressor and displacer. Cooler thermal performance has been mapped for coldtip temperatures ranging from below 45 K to above 150 K, for heat-sink temperatures ranging from 280 K to 320 K, and for a wide variety of operational variables including compressor-displacer phase, compressor-displacer stoke, drive frequency, and piston-displacer dc offset
Sericeous thyroglobulin and whole body thyroid scan in patients with differentiated thyroid cancer
International Nuclear Information System (INIS)
Mendoza, G.; Cano, R.; Morales, R.; Huanca, M.; Postigo, J.; Farfan, J.
1994-01-01
Thyroid cancer is the most frequent malignant tumor among endocrine diseases. it has an incidence of 1,87 cases per hundred thousand habitants. Thyroglobulin is an iodo glycoprotein useful in the follow-up of patients with differentiated thyroid carcinoma. Total body scan is a well established method to localize distant functioning metastases. We report the concordance of this two methods in 22 patients attending to the Nuclear Medicine Center and proceeding from the Head and Neck Department of INEN, which had undergone total thyroidectomy, received a I-131 ablative dose, performed a total body scan and determined the thyroglobulin concentration fourteen were female patients and the same number were accounted as high risk patients. We conclude for the studied population, that an excellent correlation between thyroglobulin and scans was noted and that 6,5 ng/ml will be used as a cut-off point for the thyroglobulin determination. (authors). 40 refs., 5 tabs
Energy Technology Data Exchange (ETDEWEB)
Payabvash, Seyedmehdi [Zeenat Qureshi Stroke Institute, Minneapolis, MN (United States); University of Minnesota, Department of Radiology, Minneapolis, MN (United States); Qureshi, Mushtaq H.; Khan, Shayaan M.; Khan, Mahnoor; Majidi, Shahram; Pawar, Swaroop; Qureshi, Adnan I. [Zeenat Qureshi Stroke Institute, Minneapolis, MN (United States)
2014-09-15
This study aimed to identify the imaging characteristics that can help differentiate intraparenchymal hemorrhage from benign contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients after endovascular treatment. We reviewed the clinical and imaging records of all acute ischemic stroke patients who underwent endovascular treatment in two hospitals over a 3.5-year period. The immediate post-procedural CT scan was evaluated for the presence of hyperdense lesion(s). The average attenuation of the lesion(s) was measured. Intraparenchymal hemorrhage was defined as a persistent hyperdensity visualized on follow-up CT scan, 24 h or greater after the procedure. Of the 135 patients studied, 74 (55 %) patients had hyperdense lesion(s) on immediate post-procedural CT scan. Follow-up scans confirmed the diagnosis of intraparenchymal hemorrhage in 20 of these 74 patients. A receiver operating characteristic analysis showed that the average attenuation of the most hyperdense lesion can differentiate intraparenchymal hemorrhage from contrast extravasation with an area under the curve of 0.78 (p = 0.001). An average attenuation of <50 Hounsfield units (HU) in the most visually hyperattenuating hyperdense lesion had 100 % specificity and 56 % sensitivity for identification of contrast extravasations. Petechial hyperdensity was seen in 46/54 (85 %) patients with contrast extravasation versus 9/20 (45 %) patients with intraparenchymal hemorrhage on the immediate post-procedural CT scan (p < 0.001). An average attenuation <50 HU of the most hyperattenuating hyperdense parenchymal lesion on immediate post-procedural CT scan was very specific for differentiating contrast extravasation from intraparenchymal hemorrhage in acute ischemic stroke patients after endovascular treatment. (orig.)
International Nuclear Information System (INIS)
Payabvash, Seyedmehdi; Qureshi, Mushtaq H.; Khan, Shayaan M.; Khan, Mahnoor; Majidi, Shahram; Pawar, Swaroop; Qureshi, Adnan I.
2014-01-01
This study aimed to identify the imaging characteristics that can help differentiate intraparenchymal hemorrhage from benign contrast extravasation on post-procedural noncontrast CT scan in acute ischemic stroke patients after endovascular treatment. We reviewed the clinical and imaging records of all acute ischemic stroke patients who underwent endovascular treatment in two hospitals over a 3.5-year period. The immediate post-procedural CT scan was evaluated for the presence of hyperdense lesion(s). The average attenuation of the lesion(s) was measured. Intraparenchymal hemorrhage was defined as a persistent hyperdensity visualized on follow-up CT scan, 24 h or greater after the procedure. Of the 135 patients studied, 74 (55 %) patients had hyperdense lesion(s) on immediate post-procedural CT scan. Follow-up scans confirmed the diagnosis of intraparenchymal hemorrhage in 20 of these 74 patients. A receiver operating characteristic analysis showed that the average attenuation of the most hyperdense lesion can differentiate intraparenchymal hemorrhage from contrast extravasation with an area under the curve of 0.78 (p = 0.001). An average attenuation of <50 Hounsfield units (HU) in the most visually hyperattenuating hyperdense lesion had 100 % specificity and 56 % sensitivity for identification of contrast extravasations. Petechial hyperdensity was seen in 46/54 (85 %) patients with contrast extravasation versus 9/20 (45 %) patients with intraparenchymal hemorrhage on the immediate post-procedural CT scan (p < 0.001). An average attenuation <50 HU of the most hyperattenuating hyperdense parenchymal lesion on immediate post-procedural CT scan was very specific for differentiating contrast extravasation from intraparenchymal hemorrhage in acute ischemic stroke patients after endovascular treatment. (orig.)
DEFF Research Database (Denmark)
Jeppesen, Stinus; Linderoth, Søren; Pryds, Nini
2008-01-01
A simple and high-sensitivity differential scanning calorimeter (DSC) unit operating under magnetic field has been built for indirect determination of the magnetocaloric effect. The principle of the measuring unit in the calorimeter is based on Peltier elements as heat flow sensors. The high...
Directory of Open Access Journals (Sweden)
Abdelhamid Korrir
2015-04-01
Full Text Available Avoiding strong chemical bonding, as indicated by lower heat of adsorption value, is among the selection criteria for Volatile Organic Compounds adsorbents. In this work, we highlight a non-calorimetric approach to estimating the energy of adsorption and desorption based on measurement of involved amounts, under dynamic conditions, with gaseous Fourier Transform Infrared spectroscopy. The collected data were used for obtaining adsorption heat values through the application of three different methods, namely, isosteric, temperature programmed desorption (TPD, and temperature-programmed adsorption equilibrium (TPAE. The resulting values were compared and discussed with the scope of turning determination of the heat of adsorption with non-calorimetric methods into a relevant decision making tool for designing cost-effective and safe operating of adsorption facilities.
Probing Free-Energy Surfaces with Differential Scanning Calorimetry
Sanchez-Ruiz, Jose M.
2011-05-01
Many aspects of protein folding can be understood in terms of projections of the highly dimensional energy landscape onto a few (or even only one) particularly relevant coordinates. These free-energy surfaces can be probed conveniently from experimental differential scanning calorimetry (DSC) thermograms, as DSC provides a direct relation with the protein partition function. Free-energy surfaces thus obtained are consistent with two fundamental scenarios predicted by the energy-landscape perspective: (a) well-defined macrostates separated by significant free-energy barriers, in some cases, and, in many other cases, (b) marginal or even vanishingly small barriers, which furthermore show a good correlation with kinetics for fast- and ultrafast-folding proteins. Overall, the potential of DSC to assess free-energy surfaces for a wide variety of proteins makes it possible to address fundamental issues, such as the molecular basis of the barrier modulations produced by natural selection in response to functional requirements or to ensure kinetic stability.
Hoeser, Jo; Gnandt, Emmanuel; Friedrich, Thorsten
2018-01-23
Differential scanning fluorimetry is a popular method to estimate the stability of a protein in distinct buffer conditions by determining its 'melting point'. The method requires a temperature controlled fluorescence spectrometer or a RT-PCR machine. Here, we introduce a low-budget version of a microcontroller based heating device implemented into a 96-well plate reader that is connected to a standard fluorescence spectrometer. We demonstrate its potential to determine the 'melting point' of soluble and membranous proteins at various buffer conditions.
Czech Academy of Sciences Publication Activity Database
Kumar, S.; Agrawal, K. M.; Khan, H. U.; Sikora, Antonín
2004-01-01
Roč. 22, 3 & 4 (2004), s. 337-345 ISSN 1091-6466 R&D Projects: GA AV ČR KSK4050111 Institutional research plan: CEZ:AV0Z4050913 Keywords : phase transition * hard microscrystalline waxes * differential scanning calorimetry Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.312, year: 2004
Directory of Open Access Journals (Sweden)
Johanna Gaitán-Álvarez
2018-03-01
Full Text Available We evaluated the thermogravimetric and devolatilization rates of hemicellulose and cellulose, and the calorimetric behavior of the torrefied biomass, of five tropical woody species (Cupressus lusitanica, Dipteryx panamensis, Gmelina arborea, Tectona grandis and Vochysia ferruginea, at three temperatures (TT and three torrefaction times (tT using a thermogravimetric analyzer. Through a multivariate analysis of principal components (MAPC, the most appropriate torrefaction conditions for the different types of woody biomass were identified. The thermogravimetric analysis-derivative thermogravimetry (TGA-DTG analysis showed that a higher percentage of the hemicellulose component of the biomass degrades, followed by cellulose, so that the hemicellulose energy of activation (Ea was less than that of cellulose. With an increase in TT and tT, the Ea for hemicellulose decreased but increased for cellulose. The calorimetric analyses showed that hemicellulose is the least stable component in the torrefied biomass under severe torrefaction conditions, and cellulose is more thermally stable in torrefied biomass. From the MAPC results, the best torrefaction conditions for calorimetric analyses were at 200 and 225 °C after 8, 10, and 12 min, for light and middle torrefaction, respectively, for the five woody species.
Boehm, K; Rösgen, J; Hinz, H-J
2006-02-15
A new method is described that permits the continuous and synchronous determination of heat capacity and expansibility data. We refer to it as pressure-modulated differential scanning calorimetry (PMDSC), as it involves a standard DSC temperature scan and superimposes on it a pressure modulation of preselected format. The power of the method is demonstrated using salt solutions for which the most accurate heat capacity and expansibility data exist in the literature. As the PMDSC measurements could reproduce the parameters with high accuracy and precision, we applied the method also to an aqueous suspension of multilamellar DSPC vesicles for which no expansibility data had been reported previously for the transition region. Excellent agreement was obtained between data from PMDSC and values from independent direct differential scanning densimetry measurements. The basic theoretical background of the method when using sawtooth-like pressure ramps is given under Supporting Information, and a complete statistical thermodynamic derivation of the general equations is presented in the accompanying paper.
Calorimetric sensors for energy deposition measurements
International Nuclear Information System (INIS)
Langenbrunner, J.; Cooper, R.; Morgan, G.
1998-01-01
A calorimetric sensor with several novel design features has been developed. These sensors will provide an accurate sampling of thermal power density and energy deposition from proton beams incident on target components of accelerator-based systems, such as the Accelerator Production of Tritium Project (APT) and the Spallation Neutron Source (SNS). A small, solid slug (volume = 0.347 cc) of target material is suspended by kevlar fibers and surrounded by an adiabatic enclosure in an insulating vacuum canister of stainless steel construction. The slug is in thermal contact with a low-mass, calibrated, 100-kΩ thermistor. Power deposition caused by the passage of radiation through the slug is calculated from the rate of temperature rise of the slug. The authors have chosen slugs composed of Pb, Al, and LiAl
A calorimetric study of solute effects on the kinetic stability of a-amylase
DEFF Research Database (Denmark)
Olsen, Søren Nymand; Andersen, Kim Bruno; Øgendal, Lars Holm
2009-01-01
In this study we evaluated the applications of isothermal titration calorimetry (ITC) to Study solute effects on the kinetics of irreversible protein denaturation. More specifically, denaturation of Bacillus Halmapalus alpha-amylase (BHA) was initiated by addition of EDTA to the calorimetric cell...
Directory of Open Access Journals (Sweden)
P. Pineda–Gómez
2010-06-01
Full Text Available El comportamiento térmico del almidón de maíz (Sigma Aldrich se estudió através de calorimetría diferencial de barrido (DSC. El pico endotérmico observadoen el perfil DSC se asocia al proceso de transición de gelatinizacióndel almidón. La fase inicial del proceso y el rango en el que éste ocurre, está gobernada principalmente por la concentración del almidón en solución. Enesta investigación se demuestra que los parámetros relacionados con el métodode observación, en un análisis de DSC influyen al momento de determinar lagelatinización del almidón de maíz. De esta forma, la temperatura del picode transición, la entalpía de gelatinización y el intervalo de temperatura degelatinización son los parámetros en estudio cuando se varía la humedad dela muestra y velocidad de calentamiento con un tamaño de grano homogéneo.Para los análisis, se tomaron valores de humedad de 60, 65, 70, 75 y 80%(p/p, para una velocidad de calentamiento de 2, 5 y 10◦C/min. De igualmodo, para un valor fijo de humedad (80%, se utilizó una velocidad de calentamientode 2, 5, 7, 10 y 15◦C/min. Los resultados indican que la cantidad deagua influye significativamente sobre la entalpía de gelatinización del proceso,pero la temperatura del pico Tp de la endoterma se mantiene constante. Elvalor de la entalpía disminuye a medida que la cantidad de agua aumenta.Las variaciones también son dependientes de la rapidez con que se efectúa latransformación. Los análisis permitieron corroborar, que esta transición en elalmidón es dependiente de factores extrínsecos durante el proceso. Este conocimientosobre la gelatinización del almidón es útil para optimizar procesosindustriales derivados de éste.The thermal behavior of corn starch (Sigma Aldrich was studied by differential scanning calorimetry (DSC. The endothermic peak in the DSC thermogram is associated to the starch gelatinization transition process. Initial phase of process and range in
Energy Technology Data Exchange (ETDEWEB)
Post, Ekkehard [NETZSCH Geraetebau GmbH, Wittelsbacherstrasse 42, 95100 Selb (Germany); Henderson, Jack B. [NETZSCH Instruments North America, LLC, 129 Middlesex Turnpike, Burlington, MA 01803 (United States)
2012-07-01
An illitic clay containing higher amounts of organic materials was investigated by dilatometry, thermogravimetry and differential scanning calorimetric. The evolved gases were studied during simultaneous TG-DSC (STA) and dilatometer measurements with simultaneous mass spectrometry in inert gas and oxidizing atmosphere. The dilatometer results were compared with the STA-MS results which confirmed and explained the reactions found during heating of the clay, like dehydration, dehydroxylation, shrinkage, sintering, quartz phase transition, combustion or pyrolysis of organics and the solid state reactions forming meta-kaolinite and mullite. The high amount of organic material effects in inert gas atmosphere most probably a reduction of the oxides which leads to a higher mass loss than in oxidizing atmosphere. Due to this reduction an additional CO{sub 2} emission at around 1000 deg. C was detected which did not occur in oxidizing atmosphere. Furthermore TG-MS results of a clay containing alkali nitrates show that during heating, in addition to water and CO{sub 2}, NO and NO{sub 2} are also evolved, leading to additional mass loss steps. These types of clays showed water loss starting around 100 deg. C or even earlier. This relative small mass loss affects only less shrinkage during the expansion of the sample. The dehydroxylation and the high crystalline quartz content result in considerable shrinkage and expansion of the clay. During the usual solid state reaction where the clay structure collapses, the remaining material finally shrinks down to a so-called clinker. With the help of MS the TG steps can be better interpreted as the evolved gases are identified. With the help of the MS it is possible to distinguish between CO{sub 2} and water (carbonate decomposition, oxidation of organics or dehydration/dehydroxylation). The MS also clearly shows that mass number 44 is found during the TG step of the illitic clay at about 900 deg. C in inert gas, which was interpreted
Energy Technology Data Exchange (ETDEWEB)
Bochirol, L; Bonjour, E
1967-07-01
The principle of a differential calorimeter is briefly described. The apparatus allows a direct and continuous determination of the differential heat-capacity between a sample and a reference, in the range 20 to 600 deg. K approximately. Some examples concerning measurements at low temperatures of reversible or non reversible thermal effects are given. They show the possibilities of the apparatus and are connected with: - detection and measurements of thermal effects associated to structural transformations in elastomers at low temperatures, - measurements of Wigner energy released after neutron irradiations at 77 deg. K for: recrystallized pyro-graphites; high purity iron, aluminium. [French] On decrit brievement le principe d'un calorimetre differentiel qui permet la determination directe et continue de la difference de chaleur specifique apparente entre un echantillon et une reference, dans une gamme de temperatures s'etendant de 20 a 600 deg. K environ. On donne quelques exemples de mesure a basses temperatures d'effets thermiques reversibles ou non reversibles. Ils montrent les possibilites de l'appareillage et concernent: - la detection et la mesure d'effets thermiques associes a des transformations structurales dans des elastomeres a basse temperature, - la mesure du degagement d'energie Wigner apres des irradiations neutroniques a 77 deg. K dans: des pyrographites recristallises; du fer de haute purete et de l'aluminium. (auteurs)
Calorimetric low temperature detectors for heavy ion physics
Energy Technology Data Exchange (ETDEWEB)
Egelhof, P.; Kraft-Bermuth, S. [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany)]|[Mainz Univ. (Germany). Inst. fuer Physik
2005-05-01
Calorimetric low temperature detectors have the potential to become powerful tools for applications in many fields of heavy ion physics. A brief overview of heavy ion physics at present and at the next generation heavy ion facilities is given with a special emphasis on the conditions for heavy ion detection and the potential advantage of cryogenic detectors for applications in heavy ion physics. Two types of calorimetric low temperature detectors for the detection of energetic heavy ions have been developed and their response to the impact of heavy ions was investigated systematically for a wide range of energies (E=0.1-360 MeV/amu) and ion species ({sup 4}He.. {sup 238}U). Excellent results with respect to energy resolution, {delta}E/E ranging from 1 to 5 x 10{sup -3} even for the heaviest ions, and other basic detector properties such as energy linearity with no indication of a pulse height defect, energy threshold, detection efficiency and radiation hardness have been obtained, representing a considerable improvement as compared to conventional heavy ion detectors based on ionization. With the achieved performance, calorimetric low temperature detectors bear a large potential for applications in various fields of basic and applied heavy ion research. A brief overview of a few prominent examples, such as high resolution nuclear spectroscopy, high resolution nuclear mass determination, which may be favourably used for identification of superheavy elements or in direct reaction experiments with radioactive beams, as well as background discrimination in accelerator mass spectrometry, is given, and first results are presented. For instance, the use of cryogenic detectors allowed to improve the sensitivity in trace analysis of {sup 236}U by one order of magnitude and to determine the up to date smallest isotope ratio of {sup 236}U/{sup 238}U = 6.1 x 10{sup -12} in a sample of natural uranium. Besides the detection of heavy ions, the concept of cryogenic detectors also
Calorimetric low temperature detectors for heavy ion physics
International Nuclear Information System (INIS)
Egelhof, P.; Kraft-Bermuth, S.; Mainz Univ.
2005-07-01
Calorimetric low temperature detectors have the potential to become powerful tools for applications in many fields of heavy ion physics. A brief overview of heavy ion physics at present and at the next generation heavy ion facilities is given with a special emphasis on the conditions for heavy ion detection and the potential advantage of cryogenic detectors for applications in heavy ion physics. Two types of calorimetric low temperature detectors for the detection of energetic heavy ions have been developed and their response to the impact of heavy ions was investigated systematically for a wide range of energies (E=0.1-360 MeV/amu) and ion species ( 4 He.. 238 U). Excellent results with respect to energy resolution, ΔE/E ranging from 1 to 5 x 10 -3 even for the heaviest ions, and other basic detector properties such as energy linearity with no indication of a pulse height defect, energy threshold, detection efficiency and radiation hardness have been obtained, representing a considerable improvement as compared to conventional heavy ion detectors based on ionization. With the achieved performance, calorimetric low temperature detectors bear a large potential for applications in various fields of basic and applied heavy ion research. A brief overview of a few prominent examples, such as high resolution nuclear spectroscopy, high resolution nuclear mass determination, which may be favourably used for identification of superheavy elements or in direct reaction experiments with radioactive beams, as well as background discrimination in accelerator mass spectrometry, is given, and first results are presented. For instance, the use of cryogenic detectors allowed to improve the sensitivity in trace analysis of 236 U by one order of magnitude and to determine the up to date smallest isotope ratio of 236 U/ 238 U = 6.1 x 10 -12 in a sample of natural uranium. Besides the detection of heavy ions, the concept of cryogenic detectors also provides considerable advantage for X
Skotnicki, Marcin; Gaweł, Agnieszka; Cebe, Peggy; Pyda, Marek
2013-10-01
Thermal behavior of angiotensin II type 1 (AT1) receptor antagonist, Valsartan (VAL), was examined employing thermogravimetric analysis (TGA), standard differential scanning calorimetry (DSC) and temperature-modulated differential scanning calorimetry (TMDSC). The stability of VAL was measured by TGA from 25 to 600°C. Decomposition of Valsartan starts around 160°C. The DSC curve shows two endotherms, occurring around 80°C and 100°C, related to evaporation of water and enthalpy relaxation, respectively. Valsartan was identified by DSC as an amorphous material and it was confirmed by X-ray powder diffraction. The glass transition of fresh Valsartan appears around 76°C (fictive temperature). TMDSC allows separation of the total heat flow rate into reversing and nonreversing parts. The nonreversing curve corresponds to the enthalpy relaxation and the reversing curve shows changes of heat capacity around 94°C. In the second run, TMDSC curve shows the glass transition process occurring at around 74°C. Results from standard DSC and TMDSC of Valsartan were compared over the whole range of temperature.
Samuel L. Zelinka; Michael J. Lambrecht; Samuel V. Glass; Alex C. Wiedenhoeft; Daniel J. Yelle
2012-01-01
This paper examines phase transformations of water in wood and isolated wood cell wall components using differential scanning calorimetry with the purpose of better understanding "Type II water" or "freezable bound water" that has been reported for cellulose and other hydrophilic polymers. Solid loblolly pine (Pinus taeda...
X.-M. Wang; B. Riedl; A.W. Christiansen; R.L. Geimer
1994-01-01
Phenol-formaldehyde (PF) resin is a widely used adhesive in the manufacture of wood composites. However, curing behaviour of the resin under various environmental conditions is not well known. A differential scanning calorimeter was employed to characterize the degree of resin cure in this study. Resin-impregnated glass cloth samples with varied moisture contents (0,31...
Encapsulation of UC--PuC mixture for calorimetric study
International Nuclear Information System (INIS)
Armstrong, R.E.; Link, R.P.
1976-01-01
Tantalum capsules lined with tantalum carbide were loaded with a mixture of uranium carbide-20 wt% plutonium carbide and sealed with an electron beam weld for use in Argonne National Laboratory calorimetric studies of reactor fuels. Experimental welding tests were made to determine optimum welding parameters. Special equipment available only at LLL was used and techniques were developed to perform the loading and welding operations without exposure to moisture or oxygen and with complete containment of the radioactive particles. Three capsules were successfully loaded, welded, tested, and delivered to ANL
Maria, Anton H.; Millam, Evan L.; Wright, Carrie L.
2011-01-01
As an aid for teaching phase equilibria to undergraduate students of igneous and metamorphic petrology, we have designed a laboratory exercise that allows them to create a phase diagram from data produced by differential scanning calorimetry. By preparing and analyzing samples of naphthalene and phenanthrene, students acquire hands-on insight into…
DEFF Research Database (Denmark)
Rasmussen, Peter Have; Jørgensen, Bo; Nielsen, Jette
1997-01-01
The hydration properties of proline are studied by differential scanning calorimetry (DSC) in aqueous solutions during freezing to -60 degrees C and subsequent heating to +20 degrees C. The concentration of proline in the freeze concentrated solution was estimated to approximately 50 wt% (w/w) in...... plants and insects living under water stress conditions is discussed. (C) 1997 Elsevier Science B.V....
DEFF Research Database (Denmark)
Knopp, Matthias Manne; Löbmann, Korbinian; Elder, David P.
2016-01-01
Differential scanning calorimetry (DSC) is frequently the thermal analysis technique of choice within preformulation and formulation sciences because of its ability to provide detailed information about both the physical and energetic properties of a substance and/or formulation. However, convent......-dried formulations. However, as discussed in the present review, a number of other potential applications could also be relevant for the pharmaceutical scientist....
The design of a calorimetric standard of ionising radiation absorbed dose
International Nuclear Information System (INIS)
Huntley, R.B.
1981-05-01
The design of a calorimetric working standard of ionising radiation absorbed dose is discussed. A brief history of the appropriate quantities and units of measurement is given. Detailed design considerations follow a summary of the relevant literature. The methods to be used to relate results to national standards of measurement are indicated, including the need for various correction factors. A status report is given on the construction and testing program
DEFF Research Database (Denmark)
Guo, Xiaoju; Mauro, J.C.; Allan, D.C.
2012-01-01
Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Simulations of TMDSC signals were performed for Corning EAGLE XG® glass over a wide range of modulation frequencies. Our results reveal that the frequency...... correction commonly used in the interpretation of TMDSC signals leads to a master nonreversing heat flow curve independent of modulation frequency, provided that sufficiently high frequencies are employed in the TMDSC measurement. A master reversing heat flow curve can also be generated through the frequency...
Magnetic fluid hyperthermia probed by both calorimetric and dynamic hysteresis measurements
Guibert, Clément; Fresnais, Jérôme; Peyre, Véronique; Dupuis, Vincent
2017-01-01
In this paper, we report an investigation of magnetic fluid hyperthermia (MFH) using combined calorimetric and newly implemented dynamic hysteresis measurements for two sets of well characterized size-sorted maghemite nanoparticles (with diameters of about 10 nm and 20 nm) dispersed in water and in glycerol. Our primary goal was to assess the influence of viscosity on the heating efficiency of magnetic nanoparticles described in terms of specific loss power (SLP or specific absorption rate, SAR) and dynamic hysteresis. In particular, we aimed to investigate how this SLP depends on the transition from Néelian to Brownian behavior of nanoparticles expected to occur between 10 nm and 20 nm (for maghemite) and dependent on the viscosity. While we observed a good agreement between calorimetric and dynamic hysteresis measurements, we found that the SLP measured for the different systems do not depend noticeably on the viscosity of solvent. Calculations performed according to Rosensweig's linear model [1] allow us to quantitatively reproduce our results at low field intensities, provided we use a value for the magnetic anisotropy constant much smaller than the one commonly used in the literature. This raises the question of the temperature dependance of the magnetic anisotropy constant and its relevance for a quantitative description of MFH.
DEFF Research Database (Denmark)
Guo, Xiaoju; Mauro, J.C.; Allan, D.C.
Temperature-modulated differential scanning calorimetry (TMDSC) is based on conventional DSC but with a sinusoidally modulated temperature path. Our simulations of TMDSC signals prove that the frequency correction of non-reversing heat flow can give a master curve within a certain range...... of frequencies. This frequency range is dependent not only on the measurement parameters such as linear heating/cooling rate and frequency and amplitude of the modulation, but also on the previous thermal history before the TMDSC measurement. The frequency correction for the reversing heat flow gives more...
International Nuclear Information System (INIS)
Perovic, N.L.; Maglic, K.D.; Stanimirovic, A.M.; Vukovic, G.S.
1995-01-01
The study of the thermophysical properties of AISI 321 stainless steel was the last part of work within the IAEA-coordinated Research Programme for the Establishment of a Database of Thermophysical Properties of LW and HW Reactor Materials (IAEA CRP) effected at the Institute of Nuclear Sciences Vinca (NIV). The AISI 321 stainless steel belongs to the group of construction materials whose thermophysical and calorimetric properties have significance for the IAEA CRP. Because there have been few investigations of the thermal properties of this material, the CRP foresaw the need for new measurements, which are reported in this paper. Experimental research performed at NIV consisted of the investigation of thermal diffusivity, electric resistivity, and specific heat capacity of this austenitic stainless steel. The thermal diffusivity was measured by the laser pulse technique, and the elastic resistivity and specific heat capacity were determined by use of millisecond-resolution pulse calorimetry. All measurements were performed from ambient temperature to above 1000 o C, within which temperature range the material maintains its structure and stable thermophysical properties. Values for the thermal conductivity were computed from data on the thermal diffusivity, specific heat capacity, and the room-temperature density. (author)
Novel organometallic aromatic polyester based on ferrocene
Institute of Scientific and Technical Information of China (English)
Wei
2010-01-01
A novel polyester containing ferrocenyl was prepared by low-temperature interface polycondensation of 1,1'-ferrocenedi-carboxylic acid chloride with 4-(4-hydroxyphenyl)-2,3-phthalazin-l-one(DHPZ), which is a twisted non-coplanar heterocyclic bisphenol-like monomer. The newly generated polymer was evaluated based on characterization of its solubility, viscosity measurements, elemental analysis, FTIR spectroscopy, differential scanning calorimetric and thermogravimetric studies.
Directory of Open Access Journals (Sweden)
Giuseppe Angelelli
2013-01-01
Full Text Available Purpose. To evaluate the accuracy of the washout in the differential diagnosis between adenomas and nonadenomas and to compare the obtained results in delayed CT scans at 5, 10 and 15 minutes. Methods. Fifty patients with adrenal masses were prospectively evaluated. CT scans were performed by using a 320-row MDCT device, before and after injection of contrast material. In 25 cases, delayed scans were performed at 5′ and 10′ (group 1, while in the remaining 25, at 5′ and 15′ (group 2. Absolute and relative wash-out percentage values (APW and RPW were calculated. Results. Differential diagnosis between adenomas and nonadenomas was obtained in 48/50 (96% cases, with sensitivity, specificity, and accuracy values of 96%, 95%, and 96%, respectively. In group 1, APW and RPW values were, respectively, 69.8% and 67.2% at 5′ and 75.9% and 73.5% at 10′ for adenomas and 25.1% and 15.8% at 5′ and 33.5% and 20.5% at 10′ for nonadenomas. In group 2, APW and RPW values were 63% and 54.6% at 5′ and 73.8% and 65.5% at 15′ for adenomas and 22% and 12.5% at 5′ and 35.5% and 19.9% at 15′ for nonadenomas. Conclusions. The evaluation of the wash-out values in CT scans performed at 5′, 10′, and 15′ provides comparable diagnostic results. CT scans performed at 5′ are, therefore, to be preferred, since they reduce the examination time and patient discomfort.
Remote calorimetric detection of urea via flow injection analysis.
Gaddes, David E; Demirel, Melik C; Reeves, W Brian; Tadigadapa, Srinivas
2015-12-07
The design and development of a calorimetric biosensing system enabling relatively high throughput sample analysis are reported. The calorimetric biosensor system consists of a thin (∼20 μm) micromachined Y-cut quartz crystal resonator (QCR) as a temperature sensor placed in close proximity to a fluidic chamber packed with an immobilized enzyme. Layer by layer enzyme immobilization of urease is demonstrated and its activity as a function of the number of layers, pH, and time has been evaluated. This configuration enables a sensing system where a transducer element is physically separated from the analyte solution of interest and is thereby free from fouling effects typically associated with biochemical reactions occuring on the sensor surface. The performance of this biosensing system is demonstrated by detection of 1-200 mM urea in phosphate buffer via a flow injection analysis (FIA) technique. Miniaturized fluidic systems were used to provide continuous flow through a reaction column. Under this configuration the biosensor has an ultimate resolution of less than 1 mM urea and showed a linear response between 0-50 mM. This work demonstrates a sensing modality in which the sensor itself is not fouled or contaminated by the solution of interest and the enzyme immobilized Kapton® fluidic reaction column can be used as a disposable cartridge. Such a system enables reuse and reliability for long term sampling measurements. Based on this concept a biosensing system is envisioned which can perform rapid measurements to detect biomarkers such as glucose, creatinine, cholesterol, urea and lactate in urine and blood continuously over extended periods of time.
International Nuclear Information System (INIS)
Marinescu, R.; Mincu, M.
2015-01-01
Zirconium alloys are widely used as a structural material in nuclear reactors. It is known that zirconium based cladding alloys absorb hydrogen as a result of service in a pressurized water reactor. Hydrogen absorbed (during operation of the reactor) in the zirconium alloy, out of which the pressure tube is made, is one of the major factors determining the life time of the pressure tube. For monitoring the hydrides, samples of the pressure tube are periodically taken and analyzed. At normal reactor operating temperature, hydrogen has limited solubility in the zirconium lattice and precipitates out of solid solution as zirconium hydride when the solid solubility is exceeded. As a consequences material characterization of Zr-2.5Nb CANDU pressure tubes is required after manufacturing but also during the operation to assess its structural integrity and to predict its behavior until the next in-service inspection. Hydrogen and deuterium concentration determination is one of the most important parameters to be evaluated during the experimental tests. Hydrogen present in zirconium alloys has a strong effect of weakening. Following the zirconium-hydrogen reaction, the resulting zirconium hydride precipitates in the mass of material. Weakening of the material, due to the presence of 10 ppm of precipitated hydrogen significantly affects some of its properties. The concentration of hydrogen in a sample can be determined by several methods, one of them being the differential scanning calorimetry (DSC). The principle of the method consists in measuring the difference between the amount of heat required to raise the temperature of a sample and a reference to a certain value. The experiments were made using a TA Instruments DSC Q2000 calorimeter. This paper contains experimental work for hydrogen concentration determination by Differential Scanning Calorimetry (DSC) method. Also, the reproducibility and accuracy of the method used at INR Pitesti are presented. (authors)
Physico-chemical changes in heavy ions irradiated polymer foils by differential scanning calorimetry
International Nuclear Information System (INIS)
Ciesla, K.; Trautmann, Ch.; Vansant, E.F.
1994-01-01
The sample of commercial PETP (Hostaphan) and very heavy ions irradiated products were investigated by differential scanning calorimetry in nitrogen flow. Irradiation were performed with Dy ions of 13 MeV/u with fluences 5 x 10 10 ions/cm 2 . Differences were observed in melting behaviour of unirradiated and irradiated foils. The influence of irradiation conditions on the results was noticed. Moreover the samples of polyimide (Kapton) and polycarbonate (Macrofol) irradiated in similar conditions were examined by DSC. The DSC traces have been compared with those of unirradiated reference samples. (author). 8 refs, 5 figs
International Nuclear Information System (INIS)
Brun, J.; Reynard, C.; De-Vita, C.; Carette, M.; Muraglia, M.; Lyoussi, A.; Fourmentel, D.; Guimbal, P.; Villard, J-F.
2013-06-01
Nuclear heating is a key parameter which contributes to the thermal design and the quality of in-pile experiments performed in Material Testing Reactors (MTRs) for the study of nuclear materials and fuels under irradiation. Nuclear heating is typically measured in MTRs by radiometric calorimeters. However this kind of sensor has to be suited and improved in perspective of the new experimental conditions inside the channels of Jules Horowitz Reactor (JHR). In this paper, we study the responses of two non adiabatic differential calorimeter cells having the same geometric design, but different dimensions. These experimental works are carried out during a preliminary out-of-pile calibration operating procedure of these sensors which consists in simulating the sample heating by Joule effect. The influence of the imposed electrical power and of the forced cooling flow is determined on the sensor calibration curves. A more sensitive sensor leads to a quadratic calibration curve. This behavior difference of the two calorimetric configurations is explained by means of temperature and heat flux measurements performed with a new instrumented jacket. (authors)
International Nuclear Information System (INIS)
Lin Jen-Der; Weng Hsiao-Fen; Lu Wen-Tsoung; Kao Pan-Fu; Huang Miau-Ju
1998-01-01
Radioactive iodine ( 131 I) has been found to be more sensitive and more specific than thallium-201 for the detection of distant metastases and thyroid remnants in the neck in cases of well-differentiated thyroid carcinoma. 201 Tl has been deemed particularly useful in localizing metastases or recurrence in patients with a negative 131 I scan and abnormal levels of serum thyroglobulin (Tg). This study aimed to: (1) determine the value of 201 Tl imaging in localizing metastases or recurrence in patients with well-differentiated thyroid carcinoma, and (2) evaluate the false-positive and false-negative results of 131 I and 201 Tl scintigraphy. Sixty-two thyroid remnant ablated patients who underwent simultaneous postoperative 201 Tl and 131 I scans and and serum Tg determinations were evaluated. Fifty patients had papillary thyroid carcinomas and 12 had follicular thyroid carcinomas. 201 Tl imaging was performed before the 131 I studies. Of the 62 patients who underwent 201 Tl imaging studies, 24 were found to have positive results, with local recurrence or distant metastases. Patients with positive results in the 201 Tl imaging studies tended to be older, were mor often male, had higher Tg levels and had a higher recurrence rate. Of these 24 patients, ten had negative diagnostic or therapeutic 131 I scans. Concurrently, serum Tg levels were less than 5 ng/ml in five of these ten patients. Three patients were deemed false positive by 201 Tl scans; one had a parotid tumour, one a periodontal abscess and one lung metastasis. Among the 38 patients with negative 201 Tl scans, 11 had positive findings on 131 I scans. Three had distant metastases: two with lung metastases and one with bone metastases. Patients with false-positive results on 131 I scans included those with biliary tract stones, ovarian cysts, and breast secretion. Of the 27 patients with negative 201 Tl and 131 I scans, 15 had elevated serum Tg levels. Among these, local recurrence followed by lung
X-Ray-Scattering Measurements Of Strain In PEEK
Cebe, Peggy; Lowry, Lynn E.; Chung, Shirley Y.; Yavrouian, Andre H.; Gupta, Amitava
1988-01-01
Internal stress relieved by heating above glass-transition temperature. Report describes wide-angle x-ray scattering and differential scanning calorimetry of specimens of poly(etheretherketone) having undergone various thermal treatments. Wide-angle x-ray scattering particularly useful in determining distances between atoms, crystallinity, and related microstructurally generated phenomena, as thermal expansion and strain. Calorimetric measurements aid interpretation of scattering measurements by enabling correlation with thermal effects.
International Nuclear Information System (INIS)
Derrien, Francois; Hartmanshenn, Olivier.
1978-01-01
A direct determination of the pore radii distribution is proposed using calorimetric measurements during condensation and evacuation of pores by capillary condensate. This method is independant of any gravimetric or volumetric measurement of adsorption
Automatic Gamma-Scanning System for Measurement of Residual Heat in Spent Nuclear Fuel
International Nuclear Information System (INIS)
Osifo, Otasowie
2007-03-01
In Sweden, spent nuclear fuel will be encapsulated and placed in a deep geological repository. In this procedure, reliable and accurate spent fuel data such as discharge burnup, cooling time and residual heat must be available. The gamma scanning method was proposed in earlier work as a fast and reliable method for the experimental determination of such spent fuel data. This thesis is focused on the recent achievements in the development of a pilot gamma scanning system and its application in measuring spent fuel residual heat. The achievements include the development of dedicated spectroscopic data-acquisition and analysis software and the use of a specially designed calorimeter for calibrating the gamma scanning system. The pilot system is described, including an evaluation of the performance of the spectrum analysis software. Also described are the gamma-scanning measurements on 31 spent PWR fuel assemblies performed using the pilot system. The results obtained for the determination of residual heat are presented, showing an agreement of (2-3) % with both calorimetric and calculated data. In addition, the ability to verify declared data such as discharge burnup and cooling time is demonstrated
Calorimetric Thermoelectric Gas Sensor for the Detection of Hydrogen, Methane and Mixed Gases
Directory of Open Access Journals (Sweden)
Nam-Hee Park
2014-05-01
Full Text Available A novel miniaturized calorimeter-type sensor device with a dual-catalyst structure was fabricated by integrating different catalysts on the hot (Pd/θ-Al2O3 and cold (Pt/α-Al2O3 ends of the device. The device comprises a calorimeter with a thermoelectric gas sensor (calorimetric-TGS, combining catalytic combustion and thermoelectric technologies. Its response for a model fuel gas of hydrogen and methane was investigated with various combustor catalyst compositions. The calorimetric-TGS devices detected H2, CH4, and a mixture of the two with concentrations ranging between 200 and 2000 ppm at temperatures of 100–400 °C, in terms of the calorie content of the gases. It was necessary to reduce the much higher response voltage of the TGS to H2 compared to CH4. We enhanced the H2 combustion on the cold side so that the temperature differences and response voltages to H2 were reduced. The device response to H2 combustion was reduced by 50% by controlling the Pt concentration in the Pt/α-Al2O3 catalyst on the cold side to 3 wt%.
Dong, Jie; Wang, Dawei; Ma, Zhenshen; Deng, Guodong; Wang, Lanhua; Zhang, Jiandong
2017-03-01
The aim of the study was evaluate the 3.0 T magnetic resonance (MR) perfusion imaging scanning time window following contrast injection for differentiating benign and malignant breast lesions and to determine the optimum scanning time window for increased scanner usage efficiency and reduced diagnostic adverse risk factors. A total of 52 women with breast abnormalities were selected for conventional MR imaging and T1 dynamic-enhanced imaging. Quantitative parameters [volume transfer constant (K trans ), rate constant (K ep ) and extravascular extracellular volume fraction (V e )] were calculated at phases 10, 20, 30, 40 and 50, which represented time windows at 5, 10, 15, 20 and 25 min, respectively, following injection of contrast agent. The association of the parameters at different phases with benign and malignant tumor diagnosis was analyzed. MR perfusion imaging was verified as an effective modality in the diagnosis of breast malignancies and the best scanning time window was identified: i) Values of K trans and K ep at all phases were statistically significant in differentiating benign and malignant tumors (P0.05); ii) values of V e in benign tumors increased with phase number, but achieved no obvious changes at different phases in malignant tumors; iii) the optimum scanning time window of breast perfusion imaging with 3.0 T MR was between phases 10 and 30 (i.e., between 5 and 15 min after contrast agent injection). The variation trend of V e values at different phases may serve as a diagnostic reference for differentiating benign and malignant breast abnormalities. The most efficient scanning time window was indicated to be 5 min after contrast injection, based on the observation that the V e value only had statistical significance in diagnosis at stage 10. However, the optimal scanning time window is from 5 to 15 min following the injection of contrast agent, since that the variation trend of V e is able to serve as a diagnostic reference.
Electrical and calorimetric measurements and related software
Catalan-Lasheras, N; Koratzinos, M; Rijllart, A; Siemko, A; Strait, J; Tavian, L; Wolf, R
2009-01-01
During the incident of sector 3-4 on September 19th, the temperature of a number of magnets increased over the expected values prior to the circuit failure. A review of the data logged during powering tests on all circuits indicated potential resistive splices in sectors 1-2 and 6-7. Calorimetric and electrical measurements confirmed a high resistance in magnet B16. R1 and B32R6. Systematic measurements have been performed in other cold sectors of the LHC during which the temperature increase and voltage across magnets were acquired at different currents. Cryogenic subsectors on which the temperature increase was abnormal were equipped with precise voltmeters to detect eventual resistive splices in the bus-bars. The findings of the measurement campaign will be shown as well as the plans to implement similar diagnostics as a routine check prior to powering the superconducting circuits of the LHC.
A calorimetric particle detector using an iridium superconducting phase transition thermometer
International Nuclear Information System (INIS)
Frank, M.; Dummer, D.; Cooper, S.; Igalson, J.; Proebst, F.; Seidel, W.
1994-01-01
We report on a calorimetric particles detector consisting of an 18.3 g silicon crystal and an iridium superconducting phase transition thermometer. The cryogenic calorimeter and the associated apparatus are described in detail. The pulses from irradiation with an α-particle source have a large unexpected overshoot in addition to the component expected from a naive thermal model. The pulse height spectrum displays an energy resolution of 1 percent FWHM at 6 MeV and good linearity. The noise, electrothermal feedback, and position dependence are discussed. (orig.)
Electrostatic probe and calorimetric measurements in a DC cathodic arc
International Nuclear Information System (INIS)
Lepone, Alejandro; Marquez, Adriana; Kelly, Hector; Grondona, Diana
2001-01-01
Several results obtained from measurements with spherical Langmuir probes and a calorimetric technique in a dc cathodic arc are presented. The arc is operated at a current level of 100 A, with a Copper cathode, and with Oxygen gas at a pressure in the range 0.005 divide 0.2 mbar. The measurements were performed at different axial positions in the discharge chamber. It is found that the electron temperature decreases for larger axial positions or higher pressures, but the derivation of reliable values for the ion density and kinetic energy require the consideration of atomic processes between the plasma and gas particles
International Nuclear Information System (INIS)
Takahashi, Naoya; Odano, Ikuo; Sugita, Tadashi; Sato, Yoko; Sakai, Kunio
1995-01-01
To evaluate the utility of 123 I whole body scan for detection of metastasis in patients with well-differentiated thyroid carcinoma, post-therapy whole body 131 I images in 55 cases were compared with pre-therapy 123 I images using diagnostic dose (74 MBq). The post-therapy studies were performed 7 days after administration of therapeutic doses (3.33-7.77 GBq) of 131 I. The pre-therapy scans showed 30 lesions (71.4%) of 42 lesions which were shown by 131 I post-therapy scans. The diagnostic accuracy of 123 I whole body scans was considered to be nearly the same as the images obtained by 131 I using diagnostic dose. 123 I has short-life and an optimum gamma ray energy for scintigraphy. It makes radiation dose to patients lower than that of 131 I. Therefore, we recommend pre-therapy 131 I image using diagnostic dose is replaced by 123 I image. (author)
Kumar, Arvind; Jindal, Tarun; Dutta, Roman; Kumar, Rakesh
2009-10-01
To evaluate the role of combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in differentiating bronchial tumors observed in contrast enhanced computed tomography scan of chest. Prospective observational study. Place of study: All India Institute of Medical Sciences, New Delhi, India. 7 patients with bronchial mass detected in computed tomography scan of the chest were included in this study. All patients underwent (18)F-FDG PET-CT scan, (68)Ga DOTA-TOC PET-CT scan and fiberoptic bronchoscope guided biopsy followed by definitive surgical excision. The results of functional imaging studies were analyzed and the results are correlated with the final histopathology of the tumor. Histopathological examination of 7 bronchial masses revealed carcinoid tumors (2 typical, 1 atypical), inflammatory myofibroblastic tumor (1), mucoepidermoid carcinoma (1), hamartoma (1), and synovial cell sarcoma (1). The typical carcinoids had mild (18)F-FDG uptake and high (68)Ga DOTA-TOC uptake. Atypical carcinoid had moderate uptake of (18)F-FDG and high (68)Ga DOTA-TOC uptake. Inflammatory myofibroblastic tumor showed high uptake of (18)F-FDG and no uptake of (68)Ga DOTA-TOC. Mucoepidermoid carcinoma showed mild (18)F-FDG uptake and no (68)Ga DOTA-TOC uptake. Hamartoma showed no uptake on either scans. Synovial cell sarcoma showed moderate (18)F-FDG uptake and mild focal (68)Ga DOTA-TOC uptake. This initial experience with the combined use of (18)F-FDG and (68)Ga DOTA-TOC PET-CT scan reveals different uptake patterns in various bronchial tumors. Bronchoscopic biopsy will continue to be the gold standard; however, the interesting observations made in this study merits further evaluation of the utility of the combination of (18)F-FDG PET-CT scan and (68)Ga DOTA-TOC PET-CT scan in larger number of patients with bronchial masses.
Directory of Open Access Journals (Sweden)
Matthew C. Menkiti
2015-03-01
Full Text Available This study investigated coag-flocculation (using TFC of PW and characterization of the post treatment settled sludge (PTSS. Effects of dosage, pH and settling time on treatment efficiency were evaluated. TFC and PTSS were subjected to Fourier transform infrared (FTIR, X–ray diffraction (XRD, Thermogravimetric/Differential scanning calorimetric and Scanning electron microscopic (SEM/Elemental analyses. Optimal treatment efficiency of 91.5% was obtained at 1 g/L and pH 2. It could be concluded that TFC was thermally stable and has potential for application as an effective bio-coagulant.
Feroz, S R; Mohamad, S B; Lee, G S; Malek, S N A; Tayyab, S
2015-06-01
6-Shogaol, one of the main bioactive constituents of Zingiber officinale has been shown to possess various therapeutic properties. Interaction of a therapeutic compound with plasma proteins greatly affects its pharmacokinetic and pharmacodynamic properties. The present investigation was undertaken to characterize the interaction between 6-shogaol and the main in vivo transporter, human serum albumin (HSA). Various binding characteristics of 6-shogaol-HSA interaction were studied using fluorescence spectroscopy. Thermal stability of 6-shogaol-HSA system was determined by circular dichroism (CD) and differential scanning calorimetric (DSC) techniques. Identification of the 6-shogaol binding site on HSA was made by competitive drug displacement and molecular docking experiments. Fluorescence quench titration results revealed the association constant, Ka of 6-shogaol-HSA interaction as 6.29 ± 0.33 × 10(4) M(-1) at 25 ºC. Values of the enthalpy change (-11.76 kJ mol(-1)) and the entropy change (52.52 J mol(-1) K(-1)), obtained for the binding reaction suggested involvement of hydrophobic and van der Waals forces along with hydrogen bonds in the complex formation. Higher thermal stability of HSA was noticed in the presence of 6-shogaol, as revealed by DSC and thermal denaturation profiles. Competitive ligand displacement experiments along with molecular docking results suggested the binding preference of 6-shogaol for Sudlow's site I of HSA. All these results suggest that 6-shogaol binds to Sudlow's site I of HSA through moderate binding affinity and involves hydrophobic and van der Waals forces along with hydrogen bonds. Copyright © 2015 Elsevier GmbH. All rights reserved.
Magnetic fluid hyperthermia probed by both calorimetric and dynamic hysteresis measurements
Energy Technology Data Exchange (ETDEWEB)
Guibert, Clément; Fresnais, Jérôme; Peyre, Véronique; Dupuis, Vincent, E-mail: vincent.dupuis@upmc.fr
2017-01-01
In this paper, we report an investigation of magnetic fluid hyperthermia (MFH) using combined calorimetric and newly implemented dynamic hysteresis measurements for two sets of well characterized size-sorted maghemite nanoparticles (with diameters of about 10 nm and 20 nm) dispersed in water and in glycerol. Our primary goal was to assess the influence of viscosity on the heating efficiency of magnetic nanoparticles described in terms of specific loss power (SLP or specific absorption rate, SAR) and dynamic hysteresis. In particular, we aimed to investigate how this SLP depends on the transition from Néelian to Brownian behavior of nanoparticles expected to occur between 10 nm and 20 nm (for maghemite) and dependent on the viscosity. While we observed a good agreement between calorimetric and dynamic hysteresis measurements, we found that the SLP measured for the different systems do not depend noticeably on the viscosity of solvent. Calculations performed according to Rosensweig's linear model [1] allow us to quantitatively reproduce our results at low field intensities, provided we use a value for the magnetic anisotropy constant much smaller than the one commonly used in the literature. This raises the question of the temperature dependance of the magnetic anisotropy constant and its relevance for a quantitative description of MFH. - Highlights: • Dynamic hysteresis measurements are a promising tool to study magnetic hyperthermia. • Dynamic hysteresis cycles can be reproduced using a simple model. • The effect of viscosity on hyperthermia of maghemite is weaker than expected.
Substernal thyroid carcinoma detected by 67Ga scan in a patient with normal 131I scan
International Nuclear Information System (INIS)
Kim, e.E.; Maruyama, Y.; Deland, F.H.
1978-01-01
A patient with a superior mediastinal mass on an admission chest radiograph was initially evaluated by an 131 I thyroid scan which failed to demonstrate a substernal thyroid. However, the tomographic 67 Ga scan clearly showed an abnormal uptake in the area corresponding to the mass lesion on radiographic examination. Subsequent resection and biopsy of the substernal mass revealed a poorly differentiated follicular carcinoma with foci of anaplastic carcinoma. The differential diagnosis of the anterior mediastinal mass and the usefullness of the tomographic gallium scan are briefly discussed
Energy Technology Data Exchange (ETDEWEB)
Lin Jen-Der; Weng Hsiao-Fen; Lu Wen-Tsoung [Division of Endocrinology and Metabolism, Chang Gung Memorial Hospital (Taiwan, Province of China); Kao Pan-Fu; Huang Miau-Ju [Department of Nuclear Medicine, Chang Gung Memorial Hospital, Taiwan (Taiwan, Province of China)
1998-07-01
Radioactive iodine ({sup 131}I) has been found to be more sensitive and more specific than thallium-201 for the detection of distant metastases and thyroid remnants in the neck in cases of well-differentiated thyroid carcinoma. {sup 201}Tl has been deemed particularly useful in localizing metastases or recurrence in patients with a negative {sup 131}I scan and abnormal levels of serum thyroglobulin (Tg). This study aimed to: (1) determine the value of {sup 201}Tl imaging in localizing metastases or recurrence in patients with well-differentiated thyroid carcinoma, and (2) evaluate the false-positive and false-negative results of {sup 131}I and {sup 201}Tl scintigraphy. Sixty-two thyroid remnant ablated patients who underwent simultaneous postoperative {sup 201}Tl and {sup 131}I scans and and serum Tg determinations were evaluated. Fifty patients had papillary thyroid carcinomas and 12 had follicular thyroid carcinomas. {sup 201}Tl imaging was performed before the {sup 131}I studies. Of the 62 patients who underwent {sup 201}Tl imaging studies, 24 were found to have positive results, with local recurrence or distant metastases. Patients with positive results in the {sup 201}Tl imaging studies tended to be older, were mor often male, had higher Tg levels and had a higher recurrence rate. Of these 24 patients, ten had negative diagnostic or therapeutic {sup 131}I scans. Concurrently, serum Tg levels were less than 5 ng/ml in five of these ten patients. Three patients were deemed false positive by {sup 201}Tl scans; one had a parotid tumour, one a periodontal abscess and one lung metastasis. Among the 38 patients with negative {sup 201}Tl scans, 11 had positive findings on {sup 131}I scans. Three had distant metastases: two with lung metastases and one with bone metastases. Patients with false-positive results on {sup 131}I scans included those with biliary tract stones, ovarian cysts, and breast secretion. Of the 27 patients with negative {sup 201}Tl and {sup 131}I
International Nuclear Information System (INIS)
De Robertis, E.; Cosme, E.H.H.; Neves, R.S.; Kuznetsov, A.Yu.; Campos, A.P.C.; Landi, S.M.; Achete, C.A.
2012-01-01
The purpose of this work is to investigate the applicability of the modulated temperature differential scanning calorimetry technique to measure specific heat of copper nanofluids by using the ASTM E2719 standard procedure, which is generally applied to thermally stable solids and liquids. The one-step method of preparation of copper nanofluid samples is described. The synthesized nanoparticles were separated from the base fluid and examined by X-ray diffraction and transmission electron microscopy in order to evaluate their structure, morphology and chemical nature. The presence of copper nanoparticles in the base fluid alters the characteristics of crystallization and melting processes and reduces the specific heat values of nanofluids in the whole studied temperature range. - Highlights: ► Copper nanofluids prepared by one-step method. ► Methodology of synthesis improved nanofluid stability. ► Specific heat determinations using modulated temperature differential scanning calorimetry. ► Good agreement between theoretical and experimental values.
Mora Guerrero, Carolina Del Pilar
2010-01-01
Thermodynamic functions Gibbs energy, enthalpy, and entropy of mixing of sodium naproxen and procaine hydrochloride were evaluated. Mixing quantities were calculated based on fusion calorimetric values obtained from differential scanning calorimetry measurements and equilibrium solubility values reported in the literature for both drugs in ethanol + water mixtures. By means of enthalpy-entropy compensation analysis, non-linear ΔH°mix vs. ΔG°mix plots were obtained which indicates different me...
Calorimetric investigation of an yttrium-dysprosium spin glass
International Nuclear Information System (INIS)
Wenger, L.E.
1978-01-01
In an effort to compare the spin glass characteristics of yttrium--rare earth alloys with those of the noble-metal spin glasses, the susceptibility and heat capacity of Y/sub 0.98/Dy/sub 0.02/ have been measured in the temperature range 2.5--40 K. The low-field ac susceptibility measurement shows the characteristic cusp-like peak at 7.64 K. The magnetic specific heat of the same sample shows a peak at 7.0 K and may be qualitatively described as a semi-cusp. The magnetic entropy change from absolute zero to 7 K is approximately 0.52 of cR ln(2J+1). These results are qualitatively different than previous calorimetric results on the archetypal spin glasses, AuFe and CuMn, where rounded maxima are observed at temperatures above the spin glass transition temperatures
Calorimetric method of ac loss measurement in a rotating magnetic field
Energy Technology Data Exchange (ETDEWEB)
Ghoshal, P. K. [Oxford Instruments NanoScience, Abingdon, Oxfordshire OX13 5QX (United Kingdom); Coombs, T. A.; Campbell, A. M. [Department of Engineering, Electrical Engineering, University of Cambridge, Cambridge CB3 0FA (United Kingdom)
2010-07-15
A method is described for calorimetric ac-loss measurements of high-T{sub c} superconductors (HTS) at 80 K. It is based on a technique used at 4.2 K for conventional superconducting wires that allows an easy loss measurement in parallel or perpendicular external field orientation. This paper focuses on ac loss measurement setup and calibration in a rotating magnetic field. This experimental setup is to demonstrate measuring loss using a temperature rise method under the influence of a rotating magnetic field. The slight temperature increase of the sample in an ac-field is used as a measure of losses. The aim is to simulate the loss in rotating machines using HTS. This is a unique technique to measure total ac loss in HTS at power frequencies. The sample is mounted on to a cold finger extended from a liquid nitrogen heat exchanger (HEX). The thermal insulation between the HEX and sample is provided by a material of low thermal conductivity, and low eddy current heating sample holder in vacuum vessel. A temperature sensor and noninductive heater have been incorporated in the sample holder allowing a rapid sample change. The main part of the data is obtained in the calorimetric measurement is used for calibration. The focus is on the accuracy and calibrations required to predict the actual ac losses in HTS. This setup has the advantage of being able to measure the total ac loss under the influence of a continuous moving field as experienced by any rotating machines.
Li, Si-Yu; Liu, Haiwen; Qiao, Jia-Bin; Jiang, Hua; He, Lin
2018-03-01
Negative differential conductance (NDC), characterized by the decreasing current with increasing voltage, has attracted continuous attention for its various novel applications. The NDC typically exists in a certain range of bias voltages for a selected system and controlling the regions of NDC in curves of current versus voltage (I -V ) is experimentally challenging. Here, we demonstrate a magnetic-field-controlled NDC in scanning tunneling spectroscopy of graphene npn junction resonators. The magnetic field not only can switch on and off the NDC, but also can continuously tune the regions of the NDC in the I -V curves. In the graphene npn junction resonators, magnetic fields generate sharp and pronounced Landau-level peaks with the help of the Klein tunneling of massless Dirac fermions. A tip of scanning tunneling microscope induces a relatively shift of the Landau levels in graphene beneath the tip. Tunneling between the misaligned Landau levels results in the magnetic-field-controlled NDC.
Differential magnetic force microscope imaging.
Wang, Ying; Wang, Zuobin; Liu, Jinyun; Hou, Liwei
2015-01-01
This paper presents a method for differential magnetic force microscope imaging based on a two-pass scanning procedure to extract differential magnetic forces and eliminate or significantly reduce background forces with reversed tip magnetization. In the work, the difference of two scanned images with reversed tip magnetization was used to express the local magnetic forces. The magnetic sample was first scanned with a low lift distance between the MFM tip and the sample surface, and the magnetization direction of the probe was then changed after the first scan to perform the second scan. The differential magnetic force image was obtained through the subtraction of the two images from the two scans. The theoretical and experimental results have shown that the proposed method for differential magnetic force microscope imaging is able to reduce the effect of background or environment interference forces, and offers an improved image contrast and signal to noise ratio (SNR). © Wiley Periodicals, Inc.
International Nuclear Information System (INIS)
Fang Xiangming; Hu Chunhong; Hu Xiaoyun; Chen Hongwei; Wu Liyuan; Zou Xinnong; Qian Pingyan
2006-01-01
Objective: To evaluate dynamic enhanced CT in differentiating adrenal metastases from adrenal lipid-poor adenomas(ALPA). Methods: Both plain and dynamic enhanced CT scanning was performed in 9 metastases with 13 masses and 28 lipid-poor adenoma with 30 masses. The types of time-density curve according to peak time(PT) and relative washout percentage(Washr) besides shape, size, margin, internal structure, surrounding status and enhanced pattern of each lesion were measuerd and compared between the two groups of metastases and ALPA. Results: There is difference between metastases and ALPA in the aspects of shape, density, neighboring structure and the type of enhancement. The type of TDC of matastases was characterized by fast-washin and fast-washout, which was quite differed from the type of TDC of ALPA characterized by fast-washin and slow-washout. According to this, the sensitiveity and specificity for differentiating metastases from ALPA were 96.7%, 92.3%. Conclusion: The types of TDC of dynamic enhanced CT is of great value in differentiating metastases from ALPA. (authors)
Directory of Open Access Journals (Sweden)
Asdrúbal J. Cedeño
2010-01-01
Full Text Available En este trabajo se estudió el efecto de la adición del termoplástico lineal polifenilsulfona (PPSU, sobre la cinética de reacción y las propiedades térmicas de una resina epoxídica basada en diglicidil éter de bisfenol - A (DGEBA, curada con diaminodifenilsulfona (DDS. El estudio cinético y la caracterización se realizaron mediante calorimetría diferencial de barrido, DSC estándar y modulado, bajo condiciones isotérmicas y dinámicas. La cinética del curado se discutió en el marco de tres modelos cinéticos: Kissinger, Flynn-Wall-Ozawa y el modelo cinético de orden n. Para describir la reacción de curado en su última etapa, se usó la relación semiempírica propuesta por Chern y Poehlein para considerar la influencia de la difusión sobre la rapidez de reacción. El mecanismo de curado, para todos los sistemas, se ajustó a una cinética de orden n, a pesar del contenido de PPSU, y se observó que éste se hace muy controlado por la difusión conforme aumenta el contenido de PPSU y conforme la temperatura de curado disminuye. El tiempo de vitrificación de los sistemas exhibió una fuerte dependencia con el contenido de PPSU.In this work we studied the effect of the addition of the linear thermoplastic polyphenyl sulfone (PPSU on the cure kinetics and the thermal properties of a resin based on diglycidyl ether of bisphenol-A (DGEBA, cured with 4,4´-diaminodiphenyl sulfone (DDS. The kinetic study and the characterization process have been carried out by using differential scanning calorimetry, DSC, and temperature modulated DSC (TMDSC, under isothermal and dynamic conditions. The curing kinetics was discussed in the framework of three kinetic models: Kissinger, Flynn-Wall-Ozawa, and the model of reaction of order n. To describe the cured reaction in its last stage, we have used the semiempirical relationship proposed by Chern and Poehlein to take into account the influence of diffusion on the reaction rate. The cure mechanism
Calorimetric study of bromoacetophenone isomers
International Nuclear Information System (INIS)
Amaral, Luísa M.P.F.; Ribeiro da Silva, Manuel A.V.
2014-01-01
Highlights: • A calorimetric study of bromoacetophenone isomers was performed. • Enthalpies of formation were derived by rotating-bomb combustion calorimetry. • Enthalpies of phase transition were determined by Calvet microcalorimetry. • Cox scheme was applied for the estimation of Δ f H m o (g) for the compounds. • The values of Δ f H m o (g) were compared with literature values for similar compounds. - Abstract: The standard (p o = 0.1 MPa) molar enthalpies of formation of 2-, 2′-, 3′- and 4′-bromoacetophenones were derived from the standard molar energies of combustion in oxygen, to yield CO 2 (g) and HBr·600H 2 O (l) at T = 298.15 K, measured by rotating bomb combustion calorimetry. The standard molar enthalpies associated with phase transitions of the isomers studied at T = 298.15 K, were obtained by high temperature Calvet microcalorimetry. The standard (p o = 0.1 MPa) molar enthalpies of formation of all the bromoacetophenone isomers in the gaseous phase at T = 298.15 K were derived from the experimental results. The gas-phase enthalpies of formation were also estimated by the empirical scheme developed by Cox and the values obtained were compared with the experimental ones. The results are interpreted in terms of the energetic increments for the introduction of the substituents in the benzene ring
International Nuclear Information System (INIS)
Conlu, R.A.O.; Obaldo, J.M.
2004-01-01
Background: Serum thyroglobulin assay and 131Iodine (1311) whole body scan are considered complementary in detecting malignant thyroid tissue or metastases. A large number of patients, however, are encountered presenting with scan-negative, thyroglobulin-positive differentiated thyroid carcinoma posing a dilemma in therapeutic management. One of the first alternative scanning agents to be employed is 201Thallium (201Tl). Recent studies have demonstrated its usefulness in identifying lesions that are not visualized with traditional 131I whole body scan. It is not clear, however, whether 201Tl scan helps in the decision-making for subsequent 131I therapy. This study was conducted to determine if 201Tl scan can predict therapeutic 131I uptake and to define the clinical role of 201Tl scanning in these patients. Methods and results: A total of 12 patients (20-63 y/o), 5 males and 7 females, underwent surgery for differentiated thyroid cancer and all had serum thyroglobulin values above 10 ng/ml and normal TPO autoantibodies. Pre-therapy 131I scan using 111 MBq (3mCi) of 131I were obtained. As required for inclusion, all patients had negative pre-therapy scan and negative TPO autoantibody results and underwent 20lTl scanning within 3 weeks. All patients were given 131I therapy (3.7-5.5 GBq or 100-150 mCi) between one to two months after 201Tl scanning. Within a week after therapy, all patients underwent whole body 1311 scanning. 201Tl imaging demonstrated thyroid remnants in 9 out of 12 patients having positive 201Tl scan but negative pre-therapy 1311 scan. However, only 2 of the positive 201Tl scans showed 131I uptake post-therapy (positive predictive value of 20%). None of the subjects presented with a negative 201Tl scan and a positive post-therapy 131I scan. Conclusion: Our study suggests that evidence of remnants or metastases on 201Tl scanning may be an inappropriate basis for the decision to proceed with 131I therapy. The role of 20lTl imaging in this subset of
Low-temperature transitions in cod and tuna determined by differential scanning calorimetry
DEFF Research Database (Denmark)
Jensen, Kristina Nedenskov; Jørgensen, Bo; Nielsen, Jette
2003-01-01
Differential scanning calorimetry measurements have revealed different thermal transitions in cod and tuna samples. Transition temperatures detected Lit -11degreesC, -15degreesC and -21degreesC were highly dependent on the annealing temperature. In tuna muscle an additional transition was observed...... at -72degreesC. This transition appeared differently than the thermal events observed at higher temperatures, as it spanned a broad temperature interval of 25degreesC. The transition was comparable to low-temperature glass transitions reported in protein-rich systems. No transition at this low...... temperature was detected in cod samples. The transitions observed at higher temperatures (-11degreesC to -21degreesC) may possibly stein from a glassy matrix containing muscle proteins. However, the presence of a glass transition at - 11degreesC was in disagreement with the low storage stability at -18degrees...
Faull, Katherine J; Williams, Craig R
2016-05-01
Aedes notoscriptus and Aedes aegypti are both peri-domestic, invasive container-breeding mosquitoes. While the two potential arboviral vectors are bionomically similar, their sympatric distribution in Australia is limited. In this study, analyses of Ae. aegypti and Ae. notoscriptus eggs were enabled using scanning electron microscopy. Significant variations in egg length to width ratio and outer chorionic cell field morphology between Ae. aegypti and Ae. notoscriptus enabled distinction of the two species. Intraspecific variations in cell field morphology also enabled differentiation of the separate populations of both species, highlighting regional and global variation. Our study provides a comprehensive comparative analysis of inter- and intraspecific egg morphological and morphometric variation between two invasive container-breeding mosquitoes. The results indicate a high degree of intraspecific variation in Ae. notoscriptus egg morphology when compared to the eggs of Ae. aegypti. Comparative morphological analyses of Ae. aegypti and Ae. notoscriptus egg attributes using SEM allows differentiation of the species and may be helpful in understanding egg biology in relation to biotope of origin. Copyright © 2016 Elsevier Ltd. All rights reserved.
Energy Technology Data Exchange (ETDEWEB)
Lee, Ki-Soo; Sun, Yang-Kook; Kim, Dong-Won [Department of Chemical Engineering, Hanyang University, Seungdong-gu, Seoul 133-791 (Korea); Noh, Jaegeun [Department of Chemistry, Hanyang University, Seungdong-gu, Seoul 133-791 (Korea); Song, Kwang Soup [Advanced Medical Device Center, Korea Electrotechnology, Research Institute, Ansan, Gyeonggi-do 426-170 (Korea)
2009-10-15
This study demonstrates that the addition of thiophene improves the cycle life of lithium-ion cells at high voltage. Electrochemical impedance spectroscopy results suggest that addition of thiophene significantly suppresses the increase of the charge transfer resistance that occurs during cycling up to high voltage. Differential scanning calorimetric studies showed that the thermal stability of fully charged LiCoO{sub 2} cathode was also enhanced in the presence of thiophene. (author)
Calorimetric signature of structural heterogeneity in a ternary silicate glass
DEFF Research Database (Denmark)
Zhang, Yanfei; Yang, G.; Yue, Yuanzheng
2013-01-01
We investigate the structural heterogeneity in a silicate glass by hyperquenching–annealing–calorimetry approach. The results show a striking phenomenon: two separated sub-Tg relaxation peaks appear on the calorimetric curve of the hyperquenched CaO–MgO–SiO2 glass, implying the existence of two...... distinct structural domains of higher and lower potential energies, respectively. The higher energy domains in nanoscale are so unstable that they become ordered during hyperquenching. This is verified by the high-resolution transmission electron microscopy image exhibiting nanoordered domains in the glass...... matrix. The higher energy domains relax similar to a strong glass phase, whereas the lower energy domains do similar to a fragile one....
International Nuclear Information System (INIS)
Dantas, J.M.
1983-01-01
Thermogravimetry (TG), Differential Thermogravimetry (DTG) and Differential Scanning Calorimetry (DSC) were used to characterize the thermal behavior of ammonium diuranate (ADU) and uranium trioxide (UO 3 ) produced at IPEN'S Chemical Enginnering Department. Compounds characterization was done using the molar ratios among the compounds and the oxides resulting from thermal decomposition. The TG and DTG curves registered for each sample were used for the determination of the following temperatures: - temperature of water evolution (free and crystallized water); - ammonia evolution and oxidation temperature; - ocluded ammonium nitrate decomposition temperature and - oxygen release temperature. The intermediate phases and their thermal stabilities were also identified by TG and DTG and confirmed by DSC curves, DSC curves showed also the exothermic and endothermic behavior of the processes involved. Finally, the great amount of data collected in this study can be handed as a guide by the professionals responsible for the operation of ADU,UO 3 and UF 4 pilot plants. (Author) [pt
Vermeulen, Paul. A.; Momand, Jamo; Kooi, Bart J.
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
De Rújula, A.
2015-01-01
It is in principle possible to measure directly the electron neutrino mass (or masses and mixing angles) in weak electron-capture decays. The optimal nuclide in this respect is $^{163}$Ho. The favoured experimental technique, currently pursued in various experiments (ECHo, HOLMES and NuMECS) is "calorimetric". The calorimetric energy spectrum is a sum over the unstable vacant orbitals, or "holes", left by the electrons weakly captured by the nucleus. We discuss the current progress in this field and analize the preliminary data. Our conclusion is that, as pointed out by Robertson, the contribution of two-hole states is not negligible. But --in strong contradistinction with the tacit conclusion of previous comparisons of theory and observations-- we find a quite satisfactory agreement. A crucial point is that, in the creation of secondary holes, electron shakeoff and not only electron shakeup must be taken into account.
Long-term measurement with calorimetric probes at unit 1 of V-1 nuclear power plant
International Nuclear Information System (INIS)
Erben, O.; Szasz, Z.; Jirousek, V.; Teren, S.
1989-01-01
Two calorimetric probes were tested at the first unit of the Bohunice V-1 nuclear power plant in long-term operation, i.e., during one whole reactor duty time. Each probe consisted of five fission calorimeters and one compensation calorimeter with a tungsten body. The actual calorimeters were provided with jacketed thermocouples 0.5 mm indiameter and 19 m in length. A detailed description is presented of the measuring chains and measurement techniques. Also described is the method of the disposal of the irradiated probes. The method is presented of the evaluation of measured data and the results are discussed of the analysis of these data. The measurements, including measurements during reactor shut-down and the results of the analysis of the measured data proved good viability and stability of the used calorimetres. The method of measuring the thermocouple signals is simple and the in-service evaluation of required data is quick. In order to increase measurement efficiency it would be appropriate to complete the measuring chain and to automate it. Reliability is a affected merely by protecting the thermocouples against mechanical damage during measurement probe handling and on the reactor. (Z.M.). 5 figs., 5 tabs., 5 refs
Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans
Energy Technology Data Exchange (ETDEWEB)
Okada, Kazunori, E-mail: kazokada@sfsu.edu [Department of Computer Science, San Francisco State University, San Francisco, California 94132 (United States); Rysavy, Steven [Biomedical and Health Informatics Program, University of Washington, Seattle, Washington 98195 (United States); Flores, Arturo [Computer Science and Engineering, University of California, San Diego, California 92093 (United States); Linguraru, Marius George [Sheikh Zayed Institute for Pediatric Surgical Innovation, Children’s National Medical Center, Washington, DC 20010 and Departments of Radiology and Pediatrics, George Washington University, Washington, DC 20037 (United States)
2015-04-15
Purpose: This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. Methods: The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. Results: A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon’s state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Conclusions: Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon’s conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.
Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans
International Nuclear Information System (INIS)
Okada, Kazunori; Rysavy, Steven; Flores, Arturo; Linguraru, Marius George
2015-01-01
Purpose: This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. Methods: The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. Results: A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon’s state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Conclusions: Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon’s conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions
Noninvasive differential diagnosis of dental periapical lesions in cone-beam CT scans.
Okada, Kazunori; Rysavy, Steven; Flores, Arturo; Linguraru, Marius George
2015-04-01
This paper proposes a novel application of computer-aided diagnosis (CAD) to an everyday clinical dental challenge: the noninvasive differential diagnosis of periapical lesions between periapical cysts and granulomas. A histological biopsy is the most reliable method currently available for this differential diagnosis; however, this invasive procedure prevents the lesions from healing noninvasively despite a report that they may heal without surgical treatment. A CAD using cone-beam computed tomography (CBCT) offers an alternative noninvasive diagnostic tool which helps to avoid potentially unnecessary surgery and to investigate the unknown healing process and rate for the lesions. The proposed semiautomatic solution combines graph-based random walks segmentation with machine learning-based boosted classifiers and offers a robust clinical tool with minimal user interaction. As part of this CAD framework, the authors provide two novel technical contributions: (1) probabilistic extension of the random walks segmentation with likelihood ratio test and (2) LDA-AdaBoost: a new integration of weighted linear discriminant analysis to AdaBoost. A dataset of 28 CBCT scans is used to validate the approach and compare it with other popular segmentation and classification methods. The results show the effectiveness of the proposed method with 94.1% correct classification rate and an improvement of the performance by comparison with the Simon's state-of-the-art method by 17.6%. The authors also compare classification performances with two independent ground-truth sets from the histopathology and CBCT diagnoses provided by endodontic experts. Experimental results of the authors show that the proposed CAD system behaves in clearer agreement with the CBCT ground-truth than with histopathology, supporting the Simon's conjecture that CBCT diagnosis can be as accurate as histopathology for differentiating the periapical lesions.
International Nuclear Information System (INIS)
Mesquita, Amir Zacarias; Rezende, Hugo Cesar; Souza, Rose Mary Gomes do Prado
2009-01-01
Since the first nuclear reactor was built, a number of methodological variations have been evolved for the calibration of the reactor thermal power. Power monitoring of reactors is done by means of neutronic instruments, but its calibration is always done by thermal procedures. The purpose of this paper is to present the results of the thermal power calibration carried out on March 5th, 2009 in the IPR-R1 TRIGA reactor. It was used two procedures: the calorimetric and heat balance methods. The calorimetric procedure was done with the reactor operating at a constant power, with primary cooling system switched off. The rate of temperature rise of the water was recorded. The reactor power is calculate as a function of the temperature-rise rate and the system heat capacity constant. The heat balance procedure consists in the steady-state energy balance of the primary cooling loop of the reactor. For this balance, the inlet and outlet temperatures and the water flow in the primary cooling loop were measured. The heat transferred through the primary loop was added to the heat leakage from the reactor pool. The calorimetric method calibration presented a large uncertainty. The main source of error was the determination of the heat content of the system, due to a large uncertainty in the volume of the water in the system and a lack of homogenization of the water temperature. The heat balance calibration in the primary loop is the standard procedure for calibrating the power of the IPR-R1 TRIGA nuclear reactor. (author))
International Nuclear Information System (INIS)
Rey, A.; Casas, I.; Gimenez, J.; Quinones, J.; Pablo, J. de
2009-01-01
The main objective of this work is the study of the influence of temperature on the stability of the uranyl peroxide tetrahydrate (UO 2 O 2 . 4H 2 O) 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 2 O 2 . 2H 2 O) at 373 K, and meta-schoepite (UO 3 . nH 2 O, with n 3 O 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
Chen, Yimin; Mu, Sen; Wang, Guoxiang; Shen, Xiang; Wang, Junqiang; Dai, Shixun; Xu, Tiefeng; Nie, Qiuhua; Wang, Rongping
2017-10-01
Glass transitions of Te-based phase-change materials (PCMs) were studied by modulated differential scanning calorimetry. It was found that both Ge2Sb2Te5 and GeTe are marginal glass formers with ΔT (= T x - T g) less than 2.1 °C when the heating rate is below 3 °C min-1. The fragilities of Ge2Sb2Te5 and GeTe can be estimated as 46.0 and 39.7, respectively, around the glass transition temperature, implying that a fragile-to-strong transition would be presented in such Te-based PCMs. The above results provide direct experimental evidence to support the investigation of crystallization kinetics in supercooled liquid PCMs.
Calorimetric measurements on slightly soluble gases in water
International Nuclear Information System (INIS)
Olofsson, G.; Oshodj, A.A.; Qvarnstroem, E.; Wadsoe, I.
1984-01-01
Calorimetric measurements have been made of enthalpies of solution Δsub(sol)Hsub(m)sup(infinity) in water of helium, neon, argon, krypton, xenon, methane, ethane, propane, n-butane, and oxygen at 288.15, 298.15, and 308.15 K. Values of the heat-capacity changes Δsub(sol)Csub(p,m)sup(infinity) have been derived. The found values for both the enthalpy and heat-capacity changes for the rare gases and for oxygen fully confirm the values derived by Benson and Krause, Jr. (1976), and Benson, Krause, Jr., and Peterson (1979) from the results of their very careful gas-solubility measurements. The partial molar heat capacities Csub(p,2)sup(infinity) of the hydrocarbons studied were derived. The group-additivity schemes that have been used successfully for the estimation of values for Csub(p,2)sup(infinity) for various non-ionic organic compounds do not correctly predict values of Csub(p,2)sup(infinity) for the hydrocarbons in the present study. (author)
Particle Beam Tests of the Calorimetric Electron Telescope
Tamura, Tadahisa
The Calorimetric Electron Telescope (CALET) is a new mission addressing outstanding astrophysics questions including the nature of dark matter, the sources of high-energy particles and photons, and the details of particle acceleration and transport in the galaxy by measuring the high-energy spectra of electrons, nuclei, and gamma-rays. It will launch on HTV-5 (H-II Transfer Vehicle 5) in 2014 for installation on the Japanese Experiment Module–Exposed Facility (JEM-EF) of the International Space Station. The CALET collaboration is led by JAXA and includes researchers from Japan, the U.S. and Italy. The CALET Main Telescope uses a plastic scintillator charge detector followed by a 30 radiation-length (X0) deep particle calorimeter divided into a 3 X0 imaging calorimeter, with scintillating optical fibers interleaved with thin tungsten sheets, and a 27 X0 fully-active total-absorption calorimeter made of lead tungstate scintillators. CALET prototypes were tested at the CERN (European Laboratory for Particle Ph...
DEFF Research Database (Denmark)
Daraboina, Nagu; Malmos, Christine; von Solms, Nicolas
2013-01-01
of hydrate growth. Additionally, hydrate formed in the presence of inhibitor decomposed at higher temperatures compared to pure water, indicating that while hydrate formation is initially inhibited; once hydrates form, they are more stable in the presence of inhibitor. Overall, this method proved a viable......Methane hydrate formation and decomposition were investigated in the presence of the kinetic inhibitor (Luvicap EG) and synergist (polyethylene oxide; PEO) using a high pressure micro-differential scanning calorimeter (HP-μDSC) with both temperature ramping and isothermal temperature programs....... These investigations were performed using small samples in four different capillary tubes in the calorimeter cell. When the isothermal method was employed, it was found that Luvicap EG significantly delays the hydrate nucleation time as compared to water. The results obtained from the ramping method demonstrated...
International Nuclear Information System (INIS)
Mondello, Eduardo J.; Eyheremendy, Eduardo P.; Stoisa, Daniela
2001-01-01
Purpose: To determine the value of measuring delayed post gadolinium signal intensity by displaying a curve, to make the differential diagnosis between adrenal adenomas and non-adenomas, and compare it to chemical shift MR imaging and unenhanced/delayed contrast enhanced CT. Material and methods: Nine adrenal masses have been evaluated by unenhanced/delayed contrast enhanced CT, chemical shift MR imaging and Dynamic Scan at 5, 15, 30 minutes or more, with measurement curves. The 'in phase' imaging have been compared to the 'out phase' ones. Results: Adenomas have shown drop of the curve at 30 minutes of the contrast injection. Non-adenomas have conserved an ascending curve with the same delay. Conclusion: Gadolinium-enhanced MR imaging at delayed scans can characterize adrenal masses as adenomas or non-adenomas. This technique could be considered as a new complementary diagnostic method. (author)
Calorimetric systems designed for in-field nondestructive assay of plutonium-bearing materials
International Nuclear Information System (INIS)
Roche, C.T.; Perry, R.B.; Lewis, R.N.; Jung, E.A.; Haumann, J.R.
1978-01-01
Conventional calorimetric design measures the temperature rise of a plutonium-containing sample chamber in contact with a large water-bath heat sink. This design lacks the mobility needed by inspection personnel. The Argonne National Laboratory air-chamber isothermal calorimeters are low-thermal capacitance devices which eliminate the need for large, constant-temperature heat sinks. A bulk calorimeter designed to measure sealed containers holding up to 3 kg Pu, and a small-sample calorimeter designed to measure mixed-oxide fuel pellets and powders are discussed. The operational characteristics of these instruments are described, and the results of sample assays are presented
Influencia de la adición de estaño en el proceso de precipitación en una aleación de Cu-Ni-Zn
Donoso, Eduardo C.; Diánez, Mª Jesús; Criado, José M.; Espinoza, Rodrigo; Mosquera, Edgar
2016-01-01
The influence of 1.1 wt% tin additions on the precipitation hardening of Cu-11 wt% Ni-20 wt% Zn alloy was studied by Differential Scanning Calorimetry (DSC), microhardeness measurements and High Resolution Transmission Electron Microscopy (HRTEM). The calorimetric curves, in the range of temperatures analyzed, show the presence of two exothermic reactions in the ternary alloy, associated to the short-range-order development assisted by migration of excess vacancies. On the other hand, one exo...
Obtaining and characterization of a biodegradable polymer starting from the tapioca starch
International Nuclear Information System (INIS)
Ruiz Aviles, Gladys
2006-01-01
This study focuses on the preparation of tapioca starch biodegradable polymer, processed by blends of starch modified with glycerin and water as plasticizers, by using roll mill and a single-screw extruder in the process. During extrusion, there is a series of variables to control namely: the barrel temperature profile, screw torque and screw rotation speed. Tensile test, differential scanning calorimetric (DSC), thermogravimetric analysis (TGA), Fourier transformer infrared spectroscopy (FTIR) and morphology were used in the process
Koenhen, D.M.; Smolders, C.A.
1977-01-01
The phase-separation phenomena observed in solutions of poly(2,6 dimethyl-1,4 phenylene oxide) in toluene have been investigated by differential scanning calorimetry. These measurements supplement the experimental evidence in favor of the concept that the phase transitions observed are
International Nuclear Information System (INIS)
Rady, Mohamed
2009-01-01
Characterization of the phase changing behavior of granular materials is an important issue for design and optimization of latent heat thermal energy storage (LHTES) systems. In the present work, differential scanning calorimetry (DSC) has been used to study the phase changing behavior of granular composites consisting of ceramic encapsulated phase change material (EPCM) with particle diameters of 1-3 mm. The obtained DSC curves characterizing melting and solidification of the composite material are shown to be dependent upon the values of heating and cooling rates. Direct utilization of the measured DSC curves could result in an inexact representation of the sample enthalpy change. A simple procedure has been advised to obtain accurate quantitative results from the DSC measurements based on the estimation of the thermal resistance between the sample and its enclosure. Analysis of the evolution of latent heat of EPCM with temperature at different values of cooling/heating rates is presented.
International Nuclear Information System (INIS)
Kwon, Jae Sung; Lee, Sung Keun; Kim, Doe Min; Park, Sae Jong; Jang, Kyong Sun; Kim, Eun Sil; Kim, Chong Soon
1999-01-01
We conducted a comparative study to evaluate the diagnostic values of Tl-201, Tc-99m MIBI and I-131 scans in the follow-up assessment after ablative I-131 therapy in differentiated thyroid cancer. The study population consisted of 20 patients who underwent surgical removal of thyroid cancer and ablative radioactive iodine therapy, and followed by one or more times of I-131 retreatment (33 cases). In all patients, Tl-201, Tc-99m MIBI, diagnostic and therapeutic I-131 scans were performed and the results were analyzed retrospectively. Also serum thyroglobulin levels were measured in all patients. The final diagnosis of recurrent or metastatic thyroid cancer was determined by clinical, biochemical, radiologic and/or biopsy findings. Positive rates (PR) of Tc-99m MIBI, Tl-201, diagnostic and therapeutic I-131 scans in detecting malignant thyroid tissue lesions were 70% (19/27), 54% (15/28), 35% (17/48) and 63% (30/48), respectively. The PR in the group of 20 cases (28 lesions) who underwent concomitant Tl-201 and I-131 scans were in the order of therapeutic 131 scan 71%, Tl-201 scan 54% and diagnostic I-131 scan 36%. There was no statistically significant difference between Tl-201 and diagnostic I-131 scans (p>0.05). In the group of 20 cases (27 lesions) who underwent concomitant Tc-99m MIBI and I-131 scans, the PR were in the order of Tc-99m MIBI scan 70%, I-131 therapeutic scan 52% and I-131 diagnostic scan 33%. The PR of Tc-99m MIBI was significantly higher than that of diagnostic I-131 scan (p<0.05). Tc-99m MIBI scan is superior to diagnostic I-131 scan in detecting recurrent or metastatic thyroid cancer following ablation therapy in patients with differentiated thyroid cancer. Tl-201 scan did not showed significantly higher positive rate than diagnostic I-131 scan. Instead of diagnostic I-131 scan before the I-131 retreatment, Tc-99m MIBI scan without discontinuing thyroid hormone replacement would be a prudent and effective approach in the management of these
Slit-scanning differential phase-contrast mammography: first experimental results
Roessl, Ewald; Daerr, Heiner; Koehler, Thomas; Martens, Gerhard; van Stevendaal, Udo
2014-03-01
The demands for a large field-of-view (FOV) and the stringent requirements for a stable acquisition geometry rank among the major obstacles for the translation of grating-based, differential phase-contrast techniques from the laboratory to clinical applications. While for state-of-the-art Full-Field-Digital Mammography (FFDM) FOVs of 24 cm x 30 cm are common practice, the specifications for mechanical stability are naturally derived from the detector pixel size which ranges between 50 and 100 μm. However, in grating-based, phasecontrast imaging, the relative placement of the gratings in the interferometer must be guaranteed to within micro-meter precision. In this work we report on first experimental results on a phase-contrast x-ray imaging system based on the Philips MicroDose L30 mammography unit. With the proposed approach we achieve a FOV of about 65 mm x 175 mm by the use of the slit-scanning technique. The demand for mechanical stability on a micrometer scale was relaxed by the specific interferometer design, i.e., a rigid, actuator-free mount of the phase-grating G1 with respect to the analyzer-grating G2 onto a common steel frame. The image acquisition and formation processes are described and first phase-contrast images of a test object are presented. A brief discussion of the shortcomings of the current approach is given, including the level of remaining image artifacts and the relatively inefficient usage of the total available x-ray source output.
Capelli, E.; Benes, O.; Konings, R.J.M.
2014-01-01
The work presents the measured heat capacity of the (Li1?xCax)F1+x liquid solution. Four samples with different compositions have been prepared and measured using a Differential Scanning Calorimeter. Since this technique was newly adopted for measuring encapsulated fluoride samples, some
Czech Academy of Sciences Publication Activity Database
Florian, Jakub; Brabec, Viktor
2012-01-01
Roč. 18, č. 6 (2012), s. 1634-1639 ISSN 0947-6539 R&D Projects: GA ČR(CZ) GD301/09/H004; GA ČR(CZ) GAP301/10/0598 Institutional research plan: CEZ:AV0Z50040702 Keywords : antitumor platinum * DNA * calorimetry Subject RIV: BO - Biophysics Impact factor: 5.831, year: 2012
Directory of Open Access Journals (Sweden)
Yu-Yen Chen
Full Text Available To distinguish the frequently misdiagnosed plateau iris eyes from pupillary block group and normal group, we compared the ocular biometrical parameters of them by A-scan ultrasongraphy.In total, we retrospectively reviewed general characteristics and ocular findings including ocular biometric measurements of 71 normal, 39 plateau iris, and 83 pupillary block eyes.The normal controls, plateau iris group and pupillary block group were significantly different in age, but not in gender. The anterior chamber depth tended to decrease and the lens thickness tended to increase from normal to plateau iris to pupillary block eyes. Compared to those of plateau iris group, the pupillary block group had significantly shallower anterior chamber depth (2.90mm vs. 2.33mm; p<0.001, thicker lens (4.77mm vs. 5.11mm; p<0.001, shorter axial length (23.16mm vs. 22.63mm; p<0.001, smaller relative lens position (2.28 vs. 2.16; p<0.001 and larger lens/axial length factor (2.06 vs. 2.26; p<0.001. However, when comparing plateau iris and normal eyes, only axial length and lens/axial length factor were significantly different (23.16 vs. 23.54; p<0.05 and 2.06 vs. 1.96; p<0.05.Measured by A-scan ultrasonography, the ocular biometrics of plateau iris were significantly different from those of pupillary block eyes. However, our A-scan ultrasongraphy generally found no significant biometric differences between plateau iris and normal eyes. These findings suggest that while A-scan ultrasonography might be used as a practical tool for differentiating plateau iris and papillary block eyes, a more meticulous gonioscopy and other assessments may be necessary to distinguish plateau iris from normal eyes.
The application of calorimetrical methods in nuclear technology and dosimetry
International Nuclear Information System (INIS)
Kott, J.; Krett, V.; Novotny, J.; Kovar, Z.; Jirousek, V.
1985-01-01
The report reviews theoretical as well as experimental research activities devoted to the possibilities of measuring reactor neutron and photon fields using thermic detectors based on calorimetric principle. There have been worked out theoretical principles of a reactor measuring probe intended in the first place to measuring neutron fluxes under operational temperatures inside power and research reactors, and a new philosophy of measurement has been elaborated. In addition, the report presents the experimental results as obtained on research reactors WWR-S, WWR-SM, RA, and Czechoslovak power reactor A-1 and GDR power reactor WWR-2. These results are given in connection with a newly proposed technique of reactor neutron field detection. The second part of the report presents results of works concerning beam dosimetry with the use of calorimeters
International Nuclear Information System (INIS)
Kuecuek, N.O.; Kulak, H.A.; Aras, G.
2006-01-01
The aim of this study was to evaluate the potential contribution of Tc-99m-MIBI scintigraphy to the follow-up of patients with differentiated thyroid carcinoma, who had elevated Tg levels and negative I-131 whole-body scan (WBS) results. In this retrospective study, we evaluated 28 patients with differentiated thyroid carcinoma, who had total or near total thyroidectomy followed by an ablative dose of I-131 at various time intervals (15 women, 13 men; mean age 43±17 years). All patients were treated with T4 suppression. After a mean follow-up period of 6.1 years (range 3-15) all patients were determined to have a high serum Tg concentrations (>2 ng/ml) and previous negative I-131 WBS results. All patients were examined for metastatic sites using Tc-99m-MIBI scan. Scans were visually evaluated for detecting lymph node metastases and/or local recurrence, lung metastases and skeletal metastases. Tc-99m-MIBI scan demonstrated lesions in 23 patients (83.3%). In five patients with negative Tc-99m-MIBI scan findings (FN results): Chest CT showed small-sized mediastinal LN metastases in 2 patients and lung metastases in another 2 patients (<1 cm); Neck CT showed small-sized cervical LN involvement in 1 patient. The sensitivity of detection for neck was 94.4%, for lung 63.6%, and for bone lesions 100%. For all scan sites taken together, the sensitivity of disease detection was 83.3%, the specificity was 50%, positive predictive value (PPV) was 96.2%, and finally negative predictive value (NPV) was 16.7%. We concluded that Tc-99m-MIBI scan should be considered as a supplementary scintigraphic method for the follow-up of patients with high serum Tg levels and negative I-131 WBS results, and it can help clinicians in making the decision to treat these patients. (author)
Influence of Two Compatibilizers on Clay/PP Nanocomposites Properties
DEFF Research Database (Denmark)
Potarniche, Catalina-Gabriela; Vuluga, Zina; Christiansen, Jesper de Claville
2013-01-01
-screw extruder was used to obtain nanocomposites based on polypropylene via the melt intercalation technique. X-ray diffraction and differential scanning calorimetric results showed that intercalated nanocomposites with improved thermal stability were obtained. Increases of 8% in tensile strength, 34% in modulus......, and 20% in crystallinity were observed. Also an increase of 23% in creep properties was observed when using these two compatibilizer system and 1% clay. POLYM. ENG. SCI., 00:000–000, 2012. ª2012 Society of Plastics Engineers...
Compensated-power differential calorimeter -196 deg. C/400 deg. C
International Nuclear Information System (INIS)
Bonjour, E.; Pierre, J.; Agagliate, S.; Bertrand, P.; Faivre, J.; Lagnier, R.
1967-06-01
A differential calorimetric device of original design is described. Its allows direct measurements of thermal effects (adsorption or release) during a linear rise of temperature. The self compensated power method which is applied by means of a very sensitive control system, gives a direct value of the different heat capacity between the sample and a dummy of it. The detection threshold is about ± 100 micro-watts to ± 250 micro-watts. Applications: - Generally measurements of enthalpy changes of massive or powdered samples. - Measurement of Wigner energy after low temperature irradiation (77 deg. K). - Measurements of energy release in low temperature (77 deg. K) cold worked metals. (authors) [fr
Directory of Open Access Journals (Sweden)
Luis Octavio Martínez Álvarez
2011-03-01
Full Text Available Como parte de la pre-estabilidad de la preformulación de auranofin tabletas, se realizó un estudio de compatibilidad química, para lo cual se emplearon técnicas de análisis térmico como la calorimetría diferencial de barrido y la termogravimetría. Previo a dichos estudios se caracterizó térmicamente por calorimetría diferencial de barrido el principio activo y cada uno de los excipientes. Posteriormente se procedió a la realización del estudio de compatibilidad química, mediante la preparación de mezclas físicas binarias entre el principio activo y cada uno de los excipientes. Se detectó por ambos métodos que el principio activo tuvo una transición física de fusión, no reportada en la literatura, lo que permitió poder calcular su pureza por calorimetría diferencial de barrido. Mediante la técnica calorimétrica fue posible inferir la ausencia de incompatibilidad química entre el principio activo y los excipientes estudiados. Además, mediante el cálculo de la energía de activación se estableció el siguiente orden de estabilidad térmica: auranofin:PVP> auranofin:lactosa> auranofin:explotab> auranofin:estearato> auranofin:aerosil> auranofin:celulosa, por lo que se recomienda el uso de estos excipientes en la elaboración de la formulación farmacéutica.
Total hemispherical emittance measured at high temperatures by the calorimetric method
International Nuclear Information System (INIS)
DiFilippo, F.; Mirtich, M.J.; Banks, B.A.; Stidham, C.; Kussmaul, M.
1994-01-01
A calorimetric vacuum emissometer (CVE) capable of measuring total hemispherical emittance of surfaces at elevated temperatures was designed, built, and tested. Several materials with a wide range of emittances were measured in the CVE between 773 to 923 K. These results were compared to values calculated from spectral emittance curves measured in a room temperature Hohlraum reflectometer and in an open-air elevated temperature emissometer. The results differed by as much as 0.2 for some materials but were in closer agreement for the more highly-emitting, diffuse-reflecting samples. The differences were attributed to temperature, atmospheric, and directional effects, and errors in the Hohlraum and emissometer measurements (± 5 percent). The probable error of the CVE measurements was typically less than 1 percent
Gulzar, Z; Jana, S; Young, I; Bukberg, P; Yen, V; Naddaf, S; Abdel-Dayem, H M
2001-01-01
To determine whether a 5-mCi dose of 123I can be used as an effective radiotracer for assessing the presence of remnant thyroid tissue and for searching for metastatic lesions in patients with well-differentiated thyroid cancer as well as to attempt to ascertain whether a scan performed only at 4 hours is sufficient for accurate diagnosis and might replace the conventional protocol of scanning at both 4 hours and 24 hours. We prospectively studied 27 patients who had undergone near-total thyroidectomy and had a documented diagnosis of well-differentiated thyroid carcinoma. Patients underwent scanning after receiving a 5-mCi dose of 123I, at a time when they had discontinued thyroid replacement therapy and had a thyrotropin level in excess of 30 mIU/mL. Whole-body images at 4 hours and 24 hours were obtained and were compared with posttherapy scans obtained 5 to 7 days after administration of 131I. Scans were interpreted by two board-certified nuclear medicine physicians. Of the 27 patients, 2 (7.4%) showed discordance between the 123I scan performed at 24 hours and the posttherapy 131I scan. When 4-hour images after administration of 123I were compared with the posttherapy 131I scans, a discordance rate of 14.8% (4 of 27 patients) was noted. In addition, two of these four patients showed lesions on the 24-hour images that were not seen on the 4-hour images (one with new lung metastatic involvement and the other with a local recurrence in the lower neck area). The prognosis and treatment of these two patients were substantially changed by the result of the 24-hour images. On comparison of scans obtained after administration of a 5-mCi dose of 123I with those obtained after 131I therapy, we conclude that 5 mCi of 123I produces images that have excellent quality and resolution and also compare favorably with those obtained after 131I therapy. Furthermore, a decrease in the dose of 123I from 10 mCi to 5 mCi lowered the cost of the study without compromising the
Radioactivity measurements of metallic 192Ir sources by calorimetric methods
International Nuclear Information System (INIS)
Genka, Tsuguo; Iwamoto, Seikichi; Takeuchi, Norio
1992-01-01
The necessity of establishing the traceability of dose measurement in brachytherapy 192 Ir sources is realized by physicians and researchers in the medical field. Standard sources of various shapes such as open-quotes hairpin,close quotes open-quotes single pin,close quotes open-quotes thin wire,close quotes and open-quotes seedclose quotes for calibrating ionization chambers in hospitals are being demanded. Nominal activities of not only these source products but also the standard sources have been so far specified by open-quotes apparentclose quotes values. Determination of open-quotes absoluteclose quotes activity by an established means such as 4pi-beta-gamma coincidence counting is not practical because quantitative dissolution of metallic iridium is very difficult. We tried to determine the open-quotes absoluteclose quotes activity by a calorimetric method in a fully nondestructive way
Directory of Open Access Journals (Sweden)
Hsien-Chin Wei
2017-02-01
Full Text Available Calorimetric biochemical measurements offer various advantages such as low waste, low cost, low sample consumption, short operating time, and labor-savings. Multichannel calorimeters can enhance the possibility of performing higher-throughput biochemical measurements. An enthalpy sensor (ES array is a key device in multichannel calorimeters. Most ES arrays use Wheatstone bridge amplifiers to condition the sensor signals, but such an approach is only suitable for null detection and low resistance sensors. To overcome these limitations, we have developed a multichannel calorimetric simultaneous assay (MCSA platform. An adjustable microampere constant-current (AMCC source was designed for exciting the ES array using a microampere current loop measurement circuit topology. The MCSA platform comprises a measurement unit, which contains a multichannel calorimeter and an automatic simultaneous injector, and a signal processing unit, which contains multiple ES signal conditioners and a data processor. This study focused on the construction of the MCSA platform; in particular, construction of the measurement circuit and calorimeter array in a single block. The performance of the platform, including current stability, temperature sensitivity and heat sensitivity, was evaluated. The sensor response time and calorimeter constants were given. The capability of the platform to detect relative enzyme activity was also demonstrated. The experimental results show that the proposed MCSA is a flexible and powerful biochemical measurement device with higher throughput than existing alternatives.
Perfusion lung scanning: differentiation of primary from thromboembolic pulmonary hypertension
International Nuclear Information System (INIS)
Lisbona, R.; Kreisman, H.; Novales-Diaz, J.; Derbekyan, V.
1985-01-01
Of eight patients with pulmonary arterial hypertension, final diagnosis established by autopsy or angiography, four had primary hypertension and four hypertension from thromboembolism. The perfusion lung scan was distinctly different in the two groups. The lung scan in primary pulmonary hypertension was associated with nonsegmental, patchy defects of perfusion, while in thromboembolic hypertensives it was characterized by segmental and/or lobar defects of perfusion with or without subsegmental defects. The perfusion lung scan is a valuable, noninvasive study in the evaluation of the patient with pulmonary hypertension of undetermined cause and in the exclusion of occult large-vessel pulmonary thromboembolism
Roy, Debmalya; Shastri, Babita; Mukhopadhyay, K
2012-07-12
The supramolecular assembly of the regioregular poly-3-hexylthiophene (rr-P3HT) in solution has been investigated thoroughly in the past. In the current study, our focus is on the enthalpy of nanofiber formation using thermal analysis techniques by performing the self-assembly process inside the differential scanning calorimetry (DSC) instrument. Thermogravimetric analysis (TGA) was carried out to check the concentration of the solvent during the self-assembly process of P3HT in p-xylene. Ultraviolet visible (UV-vis) spectophotometric technique, small-angle X-ray scattering (SAXS) experiment, atomic force microscopic (AFM), and scanning electron microscopic (SEM) images were used to characterize the different experimental yields generated by cooling the reaction mixture at desired temperatures. Comparison of the morphologies of self-assembled products at different fiber formation temperatures gives us an idea about the possible crystallization parameters which could affect the P3HT nanofiber morphology.
International Nuclear Information System (INIS)
Vlaeva, I; Nikolova, K; Tsankova, D; Bodurov, I; Marudova, M; Viraneva, A; Yovcheva, T; Lekova, S
2017-01-01
The potential of several physical methods for investigation of the botanical origin of honey has been discussed. Samples from the three most prevalent types of honey in Bulgaria (acacia, linden and honeydew) have been used. They have been examined by laser refractometry, UV, VIS and FTIR spectroscopy, electric conductivity measurement and differential scanning calorimetry. The purpose of this study was to reveal the physical characterizations of honeys from different flora produced in Bulgaria and to identify honeys with a high apitherapy potential for future studies. (paper)
International Nuclear Information System (INIS)
Gailhanou, H.; Gaboreau, S.; Gaucher, E.C.; Blanc, P.; Rogez, J.; Olives, J.; Amouric, M.; Van Miltenburg, J.C.; Michau, N.; Giffaut, E.
2010-01-01
(constituents of the clay mineral) + impurities. Heat capacities of the samples were measured by low-temperature adiabatic calorimetry (5 K - 350 K) and differential scanning calorimetry (300 K - 520 K), and were corrected in order to subtract the contributions of mineral impurities and, in the case of hydrated smectite, of pore water. The entropy of the mineral was determined by integrating the Cp(T)/T curve. Finally, Gibbs free energy of formation of the illite and the smectite in dehydrated and hydrated states were calculated from enthalpy and entropy of formation, at any temperature. Solubility experiments with illite IMt-2 and smectite MX-80 were carried out in either deionised water or in a solution containing NaCl 0.05 M, SiO 2,aq 5 10 -5 M, in the presence of kaolinite, hematite and goethite. The experiments were performed at 25 deg. C and lasted for two years. Solution samplings were analyzed at different time periods (3, 5 and 12 days, 3, 7, 12 and 24 months). At the end of the experiments, the solids were collected and characterized by XRD, 27 Al NMR, microprobe and TEM. Cationic exchange capacities (CEC) were also measured for Na, Ca, K and Mg. These results were compared with those obtained for the initial solids. Globally, only minor changes were detected. The more noticeable changes concern CEC values which decreases for example, from 74 meq/100 g to 59 meq/100 g for smectite after two years in water. After two years, ionic activity products are calculated from the solution analyses using the Thermochimie database. The values are compared with the equilibrium constants calculated from thermodynamic properties measured by calorimetry. It results that they lie within the uncertainty ranges defined for the equilibrium constants, which mean that solutions would be rather close to equilibrium with minerals. (authors)
Directory of Open Access Journals (Sweden)
Huihua Liu
2011-01-01
Full Text Available We studied a hydrophilic, plasticized bionanocomposite system involving sorbitol plasticizer, amylose biopolymer, and montmorillonite (MMT for the presence of competitive interactions among them at different moisture content. Synchrotron analysis via small angle X-ray scattering (SAXS and thermal analysis using differential scanning calorimetry (DSC were performed to understand crystalline growth and the distribution of crystalline domains within the samples. The SAXS diffraction patterns showed reduced interhelix spacing in the amylose network indicating strong amylose-sorbitol interactions. Depending on the sorbitol and MMT concentration, these interactions also affected the free moisture content and crystalline domains. Domains of around 95 Å and 312 Å were found in the low-moisture-content samples as compared to a single domain of 95 Å in the high-moisture-content samples. DSC measurements confirmed that the MMT increased the onset and the melting temperature of nanocomposites. Moreover, the results showed that the ternary interactions among sorbitol-amylose-MMT supported the crystalline heterogeneity through secondary nucleation.
Directory of Open Access Journals (Sweden)
Harry O'Hanley
2012-01-01
Full Text Available Nanofluids are being considered for heat transfer applications; therefore it is important to know their thermophysical properties accurately. In this paper we focused on nanofluid specific heat capacity. Currently, there exist two models to predict a nanofluid specific heat capacity as a function of nanoparticle concentration and material. Model I is a straight volume-weighted average; Model II is based on the assumption of thermal equilibrium between the particles and the surrounding fluid. These two models give significantly different predictions for a given system. Using differential scanning calorimetry (DSC, a robust experimental methodology for measuring the heat capacity of fluids, the specific heat capacities of water-based silica, alumina, and copper oxide nanofluids were measured. Nanoparticle concentrations were varied between 5 wt% and 50 wt%. Test results were found to be in excellent agreement with Model II, while the predictions of Model I deviated very significantly from the data. Therefore, Model II is recommended for nanofluids.
Gorinstein, S; Zemser, M; Vargas-Albores, F; Ochoa, J L; Paredes-Lopez, O; Scheler, C; Aksu, S; Salnikow, J
1999-02-01
Characterization of three cactus proteins (native and denatured) from Machaerocereus gummosus (Pitahaya agria), Lophocereu schottii (Garambullo), and Cholla opuntia (Cholla), was based on electrophoretic, fluorescence, CD (circular dichroism), DSC (differential scanning calorimetry), and FT-IR (Fourier transform infrared) measurements. The obtained results of intrinsic fluorescence, DSC, and CD were dissimilar for the three species of cactus, providing evidence of differences in secondary and tertiary structures. Cactus proteins may be situated in the following order corresponding to their relative stability: Machaerocereus gummosus (Pitahaya agria) > Cholla opuntia (Cholla) > Lophocereu schottii (Garambullo). Thermodynamic properties of proteins and their changes upon denaturation (temperature of denaturation, enthalphy, and the number of ruptured hydrogen bonds) were correlated with the secondary structure of proteins and disappearance of alpha-helix.
Assessment of breast tumor size in electrical impedance scanning
International Nuclear Information System (INIS)
Kim, Sungwhan
2012-01-01
Electrical impedance scanning (EIS) is a newly introduced imaging technique for early breast cancer detection. In EIS, we apply a sinusoidal voltage between a hand-held electrode and a scanning probe placed on the breast skin to make current travel through the breast. We measure induced currents (Neumann data) through the scanning probe. In this paper, we investigate the frequency-dependent behavior of the induced complex potential and show how the frequency differential of the current measurement on the scanning probe reflects the contrast in complex conductivity values between surrounding and cancerous tissues. Furthermore, we develop the formula for breast tumor size using the frequency differential of the current measurement and provide its feasibility. (paper)
International Nuclear Information System (INIS)
Hristova, N.; Piperkova, E.; Sergieva, S.; Tsingilev, D.; Fanariotov, D.; Kirilova, B.; Dimitrova, M.
1999-01-01
Postoperative follow-up study of patients with differentiated thyroid carcinoma (DTC) is currently based on periodic whole body scan (WBS) and serum thyroglobulin (Tg) assessment. The correlation between Tg levels measured and WB scans of 84 DTC patients is investigated. WBS are performed on a rotation gamma camera DIACAM (Siemens) at 48 and 72 hours after per os administration of 185-222 MBq 131 I. The levels of Tg are determined by IRMA method and kits of BYK, Germany. Normal Tg values are obtained at a control group of 27 patients free of thyroid disease. Increased Tg levels are found at 2 cases (4%) of the group of 50 patients with total thyroidectomy given 131 I without any evidence of recurrences or metastases. At the third group consisting of 18 patients with total thyroidectomy, following 131 I therapy and recurrences and/or metastases, increased Tg values were obtained in 8 cases or 44.4%. Also increased Tg levels were obtained at 4 from 16 patients (25%) subjected to total thyroidectomy but with a residual thyroid tissue proved by scintigraphy. In conclusion, a combination of both methods should be applied for improving the diagnostic and therapeutic results at the postoperative control of DTC patients
Experimental investigations on weakly polar liquid crystal-aerosil composites
Energy Technology Data Exchange (ETDEWEB)
Lobo, Chethan V; Prasad, S Krishna; Yelamaggad, C V [Centre for Liquid Crystal Research, Jalahalli, Bangalore 560013 (India)
2006-01-25
We have carried out differential scanning calorimetric and dielectric studies on composites of hydrophilic aerosil with a liquid crystal that does not possess a terminal polar group. While the shift in the nematic-isotropic transition temperature is in agreement with the general behaviour observed for such composites, the dielectric studies show, contrary to the commonly observed feature, that there is a systematic increase in the relaxation frequency associated with the rotation of the molecules around their short axis, as the aerosil concentration in the composite is increased.
International Nuclear Information System (INIS)
Pagliolico, S.L.; Sassi, G.; Cascone, Y.; Bongiovanni, R.M.
2015-01-01
Highlights: • Thermal analysis of installed wallboards embedding phase change material layer. • Simple devices and real conditions for thermal analysis toward a standardization. • Scanning calorimetric measurements as initial condition for data regression. • Bias correction of calorimetric measurements data by installation factors. • Practical approach to identify a reliable thermal curve for capacitive wallboards. - Abstract: Thermal inertia of lightweight building envelopes can be improved including phase change materials in multilayered wallboards. The thermal modeling of buildings for design purposes needs a robust description of the thermal properties of installed phase change materials. A standard method would improve the thermal characterization of commercial products. The aim of the study is to develop a simple methodology to obtain reliable thermal data for phase change materials integrated in multilayered wallboards. The methodology modifies differential scanning calorimetry measurements on phase change material by installation factors to obtain the apparent specific heat vs. temperature for the wallboard layer embedding phase change material. Simple cubic cells were realized as reference devices to simulate a confined environment. A dynamic model of heat transfer was developed to simulate the thermal behavior of devices. Installation factors were calculated by regression of the monitored temperatures inside and outside the devices operating under real environmental conditions. The apparent specific heat of phase change material, measured by differential scanning calorimetry at different rates, resulted in a spread of curves vs. temperature. Mean curves were used as initial condition for regression. The mean calculation method did not significantly affect the installed resulted curve. A unique curve of apparent specific heat vs. temperature best fit data measured over a wide range of experimental devices and conditions. Good regression
Advanced kinetics for calorimetric techniques and thermal stability screening of sulfide minerals
International Nuclear Information System (INIS)
Iliyas, Abduljelil; Hawboldt, Kelly; Khan, Faisal
2010-01-01
Thermal methods of analysis such as differential scanning calorimetry (DSC) provide a powerful methodology for the study of solid reactions. This paper proposes an improved thermal analysis methodology for thermal stability investigation of complex solid-state reactions. The proposed methodology is based on differential iso-conversional approach and involves peak separation, individual peak analysis and combination of isothermal/non-isothermal DSC measurements for kinetic analysis and prediction. The proposed thermal analysis, which coupled with Mineral Libration Analyzer (MLA) technique was employed to investigate thermal behavior of sulfide mineral oxidation. The importance of various experimental variables such as particle size, heating rate and atmosphere were investigated and discussed. The information gained from such an advanced thermal analysis method is useful for scale-up processes with potential of significant savings in plant operations, as well as in mitigating adverse environmental and safety issues arising from handling and storage of sulfide minerals.
International Nuclear Information System (INIS)
Jendrzejczyk-Handzlik, Dominika; Fitzner, Krzysztof
2011-01-01
The thermodynamic properties of the liquid Ag-Ga alloys were determined using e.m.f. and calorimetric methods. In the e.m.f. method, solid oxide galvanic cells were used with zirconia electrolyte. The cells of the type W,Ag x Ga (1-x) ,Ga 2 O 3 //ZrO 2 +(Y 2 O 3 )//FeO,Fe,W were used in the temperature range from 1098 K to 1273 K, and in the range of mole fraction from x Ga = 0.1 to x Ga = 1.0. At first, the Gibbs free energy of formation of pure solid gallium oxide, Ga 2 O 3 , from pure elements was derived. Using values of the measured e.m.f. for the cell with x Ga = 1.0, the following temperature dependence was obtained: Δ f G m,Ga 2 O 3 0 (±4kJ·mol -1 J)=-1061.7235+0.2899T/K. Next, the activity of the gallium was derived as a function of the alloy composition from the values of the measured e.m.f. Activities of silver were calculated using the Gibbs-Duhem equation. The drop calorimetric measurements were carried out at two temperatures, viz. 923 K and 1123 K, using a Setaram MHTC calorimeter. Integral enthalpies of mixing of liquid binary alloys were determined at those temperatures. Finally, thermodynamic properties of the liquid alloys were described with the Redlich-Kister equation using ThermoCalc software.
DEFF Research Database (Denmark)
Blaabjerg, Frede; Pedersen, John Kim; Ritchie, Andrew Ewen
2002-01-01
High frequency power losses in power electronic components and systems are very difficult to measure. The same applies to the efficiency of high-efficiency systems and components. An important method to measure losses with high accuracy is the calorimetric measuring systems. This paper describes...... to calibrate such systems are proposed and different applications of the system are given. Two practical examples end the description of the research. It is concluded that such systems have a relative long time-constant but they are accurate and useful for precise power loss measurement....
Maniewska, Jadwiga; Szczęśniak-Sięga, Berenika; Poła, Andrzej; Sroda-Pomianek, Kamila; Malinka, Wiesław; Michalak, Krystyna
2014-01-01
The purpose of the present paper was to assess the ability of new piroxicam analogues to interact with the lipid bilayers. The results of calorimetric and fluorescence spectroscopic experiments of two new synthesized analogues of piroxicam, named PR17 and PR18 on the phase behavior of phospholipid bilayers and fluorescence quenching of fluorescent probes (Laurdan and Prodan), which molecular location within membranes is known with certainty, are shown in present work. The presented results revealed that, depending on the details of chemical structure, the studied compounds penetrated the lipid bilayers.
Investigation of sodium - carbon dioxide interactions with calorimetric studies
International Nuclear Information System (INIS)
Simon, N.; Latge, C.; Gicquel, L.
2007-01-01
The supercritical CO 2 Brayton cycle could be a promising option to enhance the competitiveness of future Sodium fast reactors but it is highly necessary to get thermodynamic and kinetics information on potential sodium-CO 2 chemical reactions and their consequences. We have studied the interaction between Na and CO 2 via calorimetric methods. These methods are able to point out exothermic/endothermic phenomena and to measure heat of chemical reactions. The main feature of the Na/CO 2 interaction seems to be its sharp dependence on temperature. At low temperature, below 500 C degrees, CO 2 and sodium react and exhibit an induction time which decreases when temperature increases. Above 500 C degrees, we observe a global phenomenon with a fast and instantaneous chemical reaction which may be understood as an auto-combustion of CO 2 in sodium. We clearly demonstrated that Na/CO 2 interaction does not proceed as an auto-catalytic process and is more satisfactorily explained by the occurring of an auto-combustion phenomenon
A calorimetric method to determine water activity.
Björklund, Sebastian; Wadsö, Lars
2011-11-01
A calorimetric method to determine water activity covering the full range of the water activity scale is presented. A dry stream of nitrogen gas is passed either over the solution whose activity should be determined or left dry before it is saturated by bubbling through water in an isothermal calorimeter. The unknown activity is in principle determined by comparing the thermal power of vaporization related to the gas stream with unknown activity to that with zero activity. Except for three minor corrections (for pressure drop, non-perfect humidification, and evaporative cooling) the unknown water activity is calculated solely based on the water activity end-points zero and unity. Thus, there is no need for calibration with references with known water activities. The method has been evaluated at 30 °C by measuring the water activity of seven aqueous sodium chloride solutions ranging from 0.1 mol kg(-1) to 3 mol kg(-1) and seven saturated aqueous salt solutions (LiCl, MgCl(2), NaBr, NaCl, KCl, KNO(3), and K(2)SO(4)) with known water activities. The performance of the method was adequate over the complete water activity scale. At high water activities the performance was excellent, which is encouraging as many other methods used for water activity determination have limited performance at high water activities. © 2011 American Institute of Physics
McCabe, J F; Wilson, H J
1980-03-01
Thermal changes occurring during the setting of restorative materials have been measured accurately using a differential scanning calorimeter. The results were used to evaluate setting characteristics. The heat of reaction and rate of heat output may be significant in determining thermal damage to the pulp. The heat capacity is related to thermal insulation properties. These properties have been determined and their effect on the efficacy of restorative materials discussed.
AC loss measurement of superconducting dipole magnets by the calorimetric method
International Nuclear Information System (INIS)
Morita, Y.; Hara, K.; Higashi, N.; Kabe, A.
1996-01-01
AC losses of superconducting dipole magnets were measured by the calorimetric method. The magnets were model dipole magnets designed for the SSC. These were fabricated at KEK with 50-mm aperture and 1.3-m overall length. The magnet was set in a helium cryostat and cooled down to 1.8 K with 130 L of pressurized superfluid helium. Heat dissipated by the magnet during ramp cycles was measured by temperature rise of the superfluid helium. Heat leakage into the helium cryostat was 1.6 W and was subtracted from the measured heat to obtain AC loss of the magnet. An electrical measurement was carried out for calibration. Results of the two methods agreed within the experimental accuracy. The authors present the helium cryostat and measurement system in detail, and discuss the results of AC loss measurement
Hydrogen terminal solubility in Zircaloy-4
International Nuclear Information System (INIS)
Vizcaino, Pablo; Banchik, Abrahan D.
1999-01-01
Terminal solubility temperature of hydrogen in zirconium and its alloys is an important parameter because hydrides precipitation embrittled these materials making them susceptible to the phenomenon known as retarded hydrogen cracking. This work continues the study presented in the 25 AATN Meeting. Within this framework, a study focused on determining these curves in recrystallized Zircaloy-4, using scanning differential calorimetric technique. Terminal solubility curves for Zircaloy-4 were constructed within a concentration range from 40 to 640 ppm in hydrogen weight and comparisons with results obtained by other authors were made. (author)
Chromonic liquid crystalline nematic phase exhibited in binary mixture of two liquid crystals
Energy Technology Data Exchange (ETDEWEB)
Govindaiah, T. N., E-mail: tngovi.phy@gmail.com; Sreepad, H. R. [Post-Graduate Department of Physics, Government College (Autonomous), Mandya-571401 (India); Sridhar, K. N.; Sridhara, G. R.; Nagaraja, N. [Government College for Boys, Kolar-563101 (India)
2015-06-24
A binary mixture of abietic acid and orthophosphoric acid (H{sub 3}PO{sub 4}) exhibits co-existence of biphasic region of Nematic+Isotropic (N+I), lyotropic Nematic (ND) and Smectic-G (SmG) phases. The mixture exhibits N+I, N and SmG phases at different concentrations and at different temperatures. Mixtures with all concentrations of abietic acid exhibit I→N+I→N→SmG phases sequentially when the specimen is cooled from its isotropic melt. These phases have been characterized by using differential scanning calorimetric, X-ray diffraction, and optical texture studies.
Directory of Open Access Journals (Sweden)
V. G. Grossman
2017-12-01
Full Text Available The Tl2MoO4–R2(MoO43–Zr(MoO42 (R = Al, Cr systems were studied in the subsolidus region using X-ray powder diffraction and differential scanning calorimetric (DSC analysis. Quasi-binary joins were revealed, and triangulation was carried out. New ternary molybdates: Tl5RZr(MoO46 (5:1:2 and TlRZr0.5(MoO43 (1:1:1 (R = Al, Cr were prepared. The unit cell parameters for the new compounds were calculated.
Energy Technology Data Exchange (ETDEWEB)
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
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.
van Drooge, D J; Hinrichs, W L J; Visser, M R; Frijlink, H W
2006-01-01
The molecular distribution in fully amorphous solid dispersions consisting of poly(vinylpyrrolidone) (PVP)-diazepam and inulin-diazepam was studied. One glass transition temperature (T-g), as determined by temperature modulated differential scanning calorimetry (TMDSC), was observed in PVP-diazepam
International Nuclear Information System (INIS)
Facal, L.S.; Noreña, H. C.; Bruzzoni, P.
2013-01-01
The family of 9% Cr-1% Mo steels has been considered by The Generation IV International Forum as candidate materials for the construction of these prospective advanced nuclear reactors. A simple system related with these steels is the Fe-Cr-C system. In this work, a laboratory made Fe-10% Cr-0,1% C alloy has been studied. Particularly, the effect of the cooling rate on the transformations that take place when the alloy is cooled from the austenitic field was analyzed. To perform this analysis two techniques have been used: The differential scanning calorimetry (DSC) and the scanning electron microscopy (SEM). Different cooling rates of 4, 10, 50 and 90 °C/min were tested in the DSC and the resulting microstructures were observed by SEM. At the rates of 50 and 90 °C/min the cooling treatment produced a martensitic structure. Contrarily, cooling at a rate of 4 °C/min produced a microstructure consisting mainly of ferrite-pearlite with a low fraction of martensite. In the heating step which followed the cooling step, the magnetic transformation is well resolved as a broad peak which presents a maximum at 753 ± 1 °C for all the cooling rates. (author) [es
Energy Technology Data Exchange (ETDEWEB)
Naito, Akira; Fukuoka, Haruhito; Kashiwado, Kouzou; Ichiki, Toshio; Makidono, Yoko [Hiroshima Red Cross Hospital (Japan)
1984-02-01
Differential diagnosis between hepatocellular carcinoma and metastatic hepatic tumor was attempted using dynamic CT scanning. Homogeneous and patchy types were peculiar to hepatocellular carcinoma, and ring-like type to metastatic hepatic tumor. However, with no enhancement, hepatocellular carcinoma could not be denied. Hepatocellular carcinoma was characterized by the enhancement shown on the early stage of dynamic CT. Ring enhancement was not visualized on dynamic CT but visualized on conventional contrast enhanced CT in hepatocellular carcinomas; it was visualized on conventional contrast enhanced CT and on dynamic CT in metastatic hepatic tumors.
Investigations of Differential Scanning Techniques using Two Radionuclides
Energy Technology Data Exchange (ETDEWEB)
Cottrall, M. F.; French, Rosemary J.; Trott, N. G. [Institute of Cancer Research and Royal Marsden Hospital, Sutton, Surrey (United Kingdom)
1969-01-15
In the development of scanning procedures difficulties sometimes arise because a particular radiopharmaceutical, which is selectively concentrated in an organ of interest, is also widely distributed in neighbouring sites in the body. Investigations have been made of a method which involves the use of a second radioactive substance to label such sites. By means of suitable electrical circuits fitted to a conventional mechanical scanner (Picker Magnascanner III), a direct colour scan of the organ under study can be obtained. Signals from the two radionuclides are distinguished by pulse-height analysis and used to operate the colour shift mechanism. Experimental studies with phantoms and clinical trials are reported. An analysis of the statistical limitations of the technique is given, including a discussion of the most suitable operating conditions for particular pairs of radionuclides. Illustrations include the use of {sup 75}Se selenomethionine and {sup 99m}Tc sulphur colloid or {sup 198}Au colloid in the delineation of the pancreas, and reference is also made to work with {sup 18}F, {sup 99m}Tc, {sup 133m}In and {sup 197}Hg, which are used in various chemical forms to visualize specific types of tumours in vascular surroundings labelled with other suitable tracers. Some discussion of the dosimetry of these procedures is made, since the extent to which the technique can be applied may be limited by the activities which can be administered. However, successful results are being obtained using activities within the range generally accepted for single radionuclide scanning procedures. For example, the pancreas can be successfully visualised using 250 {mu}Ci {sup 75}Se selenomethionine in combination with 1 mCi {sup 99m}TC sulphur colloid. (author)
Energy Technology Data Exchange (ETDEWEB)
Casas, L. M. [Departamento de Fisica Aplicada, Facultad de Ciencias Experimentales, Universidad de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain); Plantier, F.; Bessieres, D. [Laboratoire de Thermodynamique et Energetique des Fluides Complexes-UMR 5150, Universite de Pau et des Pays de l' Adour, BP 1155, 64013 Pau (France)
2009-12-15
A new batch cell has been developed to measure simultaneously both isobaric thermal expansion and isobaric heat capacity from calorimetric measurements. The isobaric thermal expansion is directly proportional to the linear displacement of an inner flexible below and the heat capacity is calculated from the calorimetric signal. The apparatus used was a commercial Setaram C-80 calorimeter and together with this type of vessels can be operated up to 20 MPa and in the temperature range of 303.15-523.15 K, In this work, calibration was carried out using 1-hexanol and subsequently both thermophysical properties were determined for 3-pentanol, 3-ethyl-3-pentanol, and 1-octanol at atmospheric pressure, 5 and 10 MPa, and from 303.15 to 423.15 K in temperature. Finally experimental values were compared with the literature in order to validate this new methodology, which allows a very accurate determination of isobaric thermal expansion and isobaric heat capacity.
Directory of Open Access Journals (Sweden)
Grimaldi, Renato
2001-12-01
Full Text Available Palm oil (PO and palm kernel oil (PKO compositions (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 and 0/100 were interesterified in laboratory scale under predetermined conditions (0.4% sodium metoxide, 20 minutes, 100ºC. The fourteen samples, before and after interesterification, were characterized by Polarized Light Microscopy and Differential Scanning Calorimetry (DSC. Results showed the effect of various factors on the form and width of crystals. The mean area of crystals revealed the increase of crystals when PKO was added, with values varying from 2.7 x 10E3 µm2 to PO and 1.8 x 10E6 µm2 to PKO. After interesterification, the crystal widths were lower at PO/PKO 100/0, 80/20, 60/40, 20/80 fractions and were higher to anothers. The beta-prime polimorphic form was observed in the pure palm oil sample. The results showed in melting curves, onset values from –19.6ºC to more unsaturated peaks until 20.7ºC to more saturated ones. The higher values to more saturated peak in a melting curve to palm oil, 38.7 J.g-1 before and 48.4 J.g-1 after interesterification, showed a mores table saturated group. I n a genera l way, t h e interesterification promoted an increase of crystallization rate and a better compatibility between PO/PKO fractions.Fueron interesterificados en el laboratorio mezclas de aceite de palma (PO y aceite de palmiste (PKO en diferentes proporciones (100/0, 80/20, 60/40, 50/50, 40/60, 20/80 y 0/100 bajo condiciones predeterminadas (0.4% metoxido de sodio, 20 minutos, 100ºC. Las catorce muestras fueron caracterizadas antes y después de la interesterificación por Microscopía de Luz Polarizada y por Calorimetría Diferencial de Barrido (DSC. Los resultados mostraron el efecto de varios factores sobre la forma y anchura de los cristales. El área media de los cristales revela el aumento de tamaño de los mismos cuando aumenta la proporción de PKO, con valores que varían entre 2.7 x 10E3 µm2 para PO y 1.8 x 10E
Clinical and CT scan pictures of cerebral cysticercosis
Energy Technology Data Exchange (ETDEWEB)
Singounas, E.G.; Krassanakis, K.; Karvounis, P.C. (Evangelismos Hospital, Athens (Greece))
1982-01-01
The clinical presentations and CT scan pictures of four patients harbouring big cysticercus cysts are described. The value of CT scanning in detecting these cysts is emphasized, and also the fact that these cysts can behave as space-occyping lesions, which must be differentiated from other cystic formations.
Saito, Terubumi; Tatsuta, Muneaki; Abe, Yamato; Takesawa, Minato
2018-02-01
We have succeeded in the direct measurement for solar cell/module internal conversion efficiency based on a calorimetric method or electrical substitution method by which the absorbed radiant power is determined by replacing the heat absorbed in the cell/module with the electrical power. The technique is advantageous in that the reflectance and transmittance measurements, which are required in the conventional methods, are not necessary. Also, the internal quantum efficiency can be derived from conversion efficiencies by using the average photon energy. Agreements of the measured data with the values estimated from the nominal values support the validity of this technique.
Thermodynamic and Calorimetric Study of Acetylsalicylic Acid (Aspirin and Ibuprofen
Directory of Open Access Journals (Sweden)
Juan Carlos Moreno-Piraján
2011-01-01
Full Text Available Enthalpies of solution and dilution of aqueous solutions of sodium acetylsalicylic acid salt and ibuprofen salt were measured with an isoperibolic calorimeter at 293.15 K, 298.15 K, 303.15 K, 308.15 K and 318.15 K. The concentration of the electrolyte was restricted to the solubility of the salt at various temperatures and did not exceed 0.035–0.057 mol kg-1, depending on the temperature studied. The Virial coefficients were derived from Pitzer's model and the excess thermodynamic functions of both the solution and the components of the solution were calculated. An analysis of the thermodynamic characteristics of the solution in terms of concentration and temperature interval was carried out and discussed. Additionally, an analysis was performed by differential scanning calorimetry (DSC.
DEFF Research Database (Denmark)
Holopainen, J. M.; Lemmich, Jesper; Richter, F.
2000-01-01
hydrated binary membranes composed of dimyristoylphosphatidylcholine (DMPC) and N-palmitoyl-ceramide (C16:0-ceramide, up to a mole fraction X-cer = 0.35) were resolved in further detail by high-sensitivity differential scanning calorimetry (DSC) and x-ray diffraction. Both methods reveal very strong...... hysteresis in the thermal phase behavior of ceramide-containing membranes. A partial phase diagram was constructed based on results from a combination of these two methods. DSC heating scans show that with increased X-cer the pretransition temperature T-P first increases, whereafter at X-cer > 0.06 it can...... no longer be resolved. The main transition enthalpy Delta H remains practically unaltered while its width increases significantly, and the upper phase boundary temperature of the mixture shifts to similar to 63 degrees C at X-cer = 0.30. Upon cooling, profound phase separation is evident, and for all...
Calorimetric investigations of UPb{sub 3} compound
Energy Technology Data Exchange (ETDEWEB)
Agarwal, Renu, E-mail: arenu@barc.gov.in; Samui, Pradeep; Mukerjee, S.K.
2016-08-10
Highlights: • First time reporting of enthalpy increment and heat capacity data of UPb{sub 3} compound. • First time reporting of high temperature calorimetric determination of enthalpy of formation of UPb{sub 3} compound. • Miedema model was used to calculate enthalpies of formation of UPb{sub 3} and UPb. • Thermodynamic table of the compound UPb{sub 3} was generated. - Abstract: Interaction of uranium based metallic fuels and lead coolant can lead to formation of intermetallic compounds of U-Pb system. To understand U-Pb interactions, it is important to know thermodynamic properties of intermetallic compounds present in this system, UPb{sub 3} and UPb. In the present work, enthalpy increment, heat capacity and enthalpy of formation of UPb{sub 3} intermetallic compound were determined. The enthalpy increment was determined by high temperature Calvet calorimeter and heat capacity was determined using DSC. The heat capacity data was used to calculate thermodynamic parameters of the compound as a function of temperature. The enthalpy of formation at 843 K was determined using successive precipitation method, by direct reaction calorimetry. The enthalpy of formation at 843 K, from Pb(l) and U(l), was −28.9 kJ at-mol{sup −1} and after adjusting enthalpy increments of pure elements and compound, the enthalpy of formation of the compound at 298 K, from Pb(s) and U(α) was found to be −20.0 kJ at-mol{sup −1}.
Directory of Open Access Journals (Sweden)
Hourston Douglas J.
2001-01-01
Full Text Available The interfacial structure of poly(styrene (PS-poly(methyl acrylate (PMA structured latices has been investigated by means of modulated-temperature differential scanning calorimetry (M-TDSC and small-angle x-ray scattering (SAXS. The differential of heat capacity, dCp/dT, signal from M-TDSC was used to quantify the weight fraction of interface in these latices. For PS-PMA (50:50 by weight structured latices in which the PS component had different crosslink densities (0, 1, 3, 5 and 10 mol% of crosslinking agent, the weight fraction of interface was about 13%. With increasing crosslink density, the fraction of interface increased only slightly. A core-shell model has been used to analyse SAXS data for these PS-PMA latices. M-TDSC can only provide information about the weight fraction of interface, but the combination of M-TDSC and SAXS can provide much more information on the morphology of such structured latices.
Model for calorimetric measurements in an open quantum system
Donvil, Brecht; Muratore-Ginanneschi, Paolo; Pekola, Jukka P.; Schwieger, Kay
2018-05-01
We investigate the experimental setup proposed in New J. Phys. 15, 115006 (2013), 10.1088/1367-2630/15/11/115006 for calorimetric measurements of thermodynamic indicators in an open quantum system. As a theoretical model we consider a periodically driven qubit coupled with a large yet finite electron reservoir, the calorimeter. The calorimeter is initially at equilibrium with an infinite phonon bath. As time elapses, the temperature of the calorimeter varies in consequence of energy exchanges with the qubit and the phonon bath. We show how under weak-coupling assumptions, the evolution of the qubit-calorimeter system can be described by a generalized quantum jump process including as dynamical variable the temperature of the calorimeter. We study the jump process by numeric and analytic methods. Asymptotically with the duration of the drive, the qubit-calorimeter attains a steady state. In this same limit, we use multiscale perturbation theory to derive a Fokker-Planck equation governing the calorimeter temperature distribution. We inquire the properties of the temperature probability distribution close and at the steady state. In particular, we predict the behavior of measurable statistical indicators versus the qubit-calorimeter coupling constant.
Comparison between DSC and TMDSC in the investigation into frozen aqueous cryoprotectants solutions.
Santoveña, A; Piñero, M J; Llabrés, M
2010-12-01
The influence of thermal parameters in the observation of thermal events and in the calculation of heat transformation in aqueous cryoprotectant solutions after freezing was investigated using conventional differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC), respectively. The systems under study were formed by pure water and diluted aqueous solutions of mannitol, trehalose, sucrose, sorbitol, and glycine. The influence of different combinations of frequency and amplitude was analyzed in heating-cooling and heating-iso TMDSC scans. Trehalose, sucrose, and sorbitol present a lesser critical temperature of primary drying than other cryoprotectants studied. The calorimetric variables selection is crucial to detect or not the thermal events, or to detect so with different numerical values. Then, the values of the calorimetric parameters determined are different if measured in a mode of heating-cooling or heating-iso. The TMDSC method-1 used in this study employs a higher number of cycles in each thermal event. The use of Lissajous figures and the study of the C(p in-phase) signal evolution will allow us to understand the complexity of the events detected. The comparative study of both techniques points to the selection of conventional or modulated technique depending on the type of system and the nature of the studied events.
Broadband dielectric spectroscopy and calorimetric investigations of D-lyxose.
Singh, Lokendra P; Alegría, A; Colmenero, J
2011-10-18
Using broadband dielectric spectroscopy, we have studied different types of relaxation processes, namely, primary (α), secondary (β), and another sub-T(g) process called γ-process, in the supercooled state of D-lyxose, over a wide frequency (10(-2)-10(9) Hz) and temperature range (120-340 K). In addition, the same sample was analyzed by differential scanning calorimeter. The temperature dependence of the relaxation times as well as the dielectric strength of different processes has been critically examined. It has been observed that the slower secondary relaxation (designated as β-) process shifts to lower frequencies with increasing applied pressure, but not the faster one. This pressure dependence indicates that the observed slower secondary relaxation (β-) is Johari-Goldstein relaxation process and faster one (γ-process) is probably the rotation of hydroxymethyl (-CH(2)OH) side group attached to the sugar ring, that is, of intramolecular origin. Copyright © 2011 Elsevier Ltd. All rights reserved.
Thermally decarboxylated sodium bicarbonate: Interactions with water vapour, calorimetric study
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Natalia Volkova
2013-06-01
Full Text Available Isothermal titration calorimetry (ITC was used to study interactions between water vapour and the surface of thermally converted sodium bicarbonate (NaHCO3. The decarboxylation degree of the samples was varied from 3% to 35% and the humidity range was 54â100%. The obtained enthalpy values were all exothermic and showed a positive linear correlation with decarboxylation degrees for each humidity studied. The critical humidity, 75% (RHo, was determined as the inflection point on a plot of the meanâÎHkJ/mole Na2CO3 against RH. Humidities above the critical humidity lead to complete surface dissolution. The water uptake (m was determined after each calorimetric experiment, complementing the enthalpy data. A mechanism of water vapour interaction with decarboxylated samples, including the formation of trona and Wegscheiderâs salt on the bicarbonate surface is proposed for humidities below RHo. Keywords: Isothermal titration calorimetry, Sodium bicarbonate, Sodium carbonate, Trona salt, Wegscheiderâs salt, Enthalpy, Relative humidity, Pyrolytic decarboxylation
Energy Technology Data Exchange (ETDEWEB)
Hajlaoui, Sondes, E-mail: hajlaouisondes@yahoo.fr [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia); Chaabane, Iskandar [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia); Lhoste, Jérôme; Bulou, Alain [LUNAM Université, Université du Maine, CNRS UMR 6283, Institut des Molécules et Matériaux du Mans (IMMM), Avenue Olivier Messiaen, 72085, Le Mans, Cedex 9 (France); Guidara, Kamel [Unité de recherche de la matière condensée, Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax (Tunisia)
2016-09-15
In this work a novel compound tertrapropylammonium aquapentachlorostannate dihydrate was synthesized and characterized by; single crystal X-ray diffraction, vibrational spectroscopy, differential scanning calorimetric and dielectric measurement. The crystal structure refinement at room temperature reveled that this later belongs to the monoclinic compound with P121/c1 space group with the following unit cell parameters a = 8.2699(3) Å, b = 12.4665(4) Å, c = 22.3341(7) Å and β = 92.94(0)°. The crystal arrangement can be described by stacked organic-inorganic layers in the c direction with two independent water molecules placed between each two layers. The detailed interpretations of the vibrational properties of the studied compound were performed using density functional theory (DFT) with the B3LYP/LanL2DZ basis set, and has enabled us to make the detailed assignments by comparative study of the experimental and calculated Raman and IR spectra. The differential scanning calorimetry (DSC) measurement disclosed two anomalies in the temperature range 356–376 (T{sub 1}) K and at 393 K (T{sub 2}) characterized by the dehydration of the sample and probably a reconstruction of a new structure after T{sub 2} transition. The temperature dependences of dielectric permittivity show a relaxation process around T{sub 2} anomaly indicating the occurrence of the disorder at high temperature. The dependence of the exponent m(T) on temperature, extracted from the straight lines of log(ε″) with log (ω), suggests that the correlated barrier hopping is the appropriate model for the conduction mechanism. - Highlights: • The single-crystal X-ray diffraction has been performed. • The assignments of the vibration modes based on DFT were reported and discussed. • Differential scanning calorimetric reveals the presence of two endothermic peaks. • The electric permittivity was studied using the impedance measurements. • The CBH is the appropriate model for the conduction
Effect of aerosil dispersions on the photoinduced nematic-isotropic transition
Energy Technology Data Exchange (ETDEWEB)
Jayalakshmi, V; Nair, Geetha G; Prasad, S Krishna [Centre for Liquid Crystal Research, Jalahalli, Bangalore 560013 (India)
2007-06-06
We report differential scanning calorimetric (DSC) and dielectric measurements on the nematic-isotropic transition in the bulk and aerosil composites of a liquid-crystal mixture having a photoactive guest azobenzene compound in a non-photoactive host, 4-n-heptyl cyanobiphenyl (7CB). The DSC scans taken at different cooling rates show that, at slower rates, the bulk displays a single peak across the transition, whereas the composites in the soft gel regime exhibit a double-peak profile. Such a double-peak profile, although seen in high-resolution ac calorimetric studies, has been observed for the first time in DSC experiments. The temperature range of the region between the two peaks is comparable to that seen in ac calorimetric experiments and has similar features. This observation is significant since the appearance of the low-temperature peak in ac calorimetric data has been explained to be due to a crossover from the random-dilution to the random-field limits. This work also constitutes the first experiments on the photoisomerization driven isothermal phase transitions in liquid-crystal-aerosil composites. The studies carried out in the absence and presence of a low-magnitude UV radiation not only bring out the standard features now established for such photostimulated phase transitions, but display a few surprises. Notable among them are that (i) the photoinduced shift in the transition temperature is a non-monotonic function of the aerosil composition and appears qualitatively similar to the dependence of the transition temperature itself, and (ii) the thermal anomaly mentioned above characterizing the crossover is also seen in the temperature-dependent as well as the temporal variation of the sample capacitance for a composite in the soft gel regime. We have also evaluated, using the temporal variation of the capacitance, the different response times associated with the UV-on photochemical process as well as the UV-off thermal back-relaxation process; the
Kaur, Bhupinder; Quek Yu Chin, Rina; Camps, Stefan; Henry, Christiani Jeyakumar
2016-06-01
Low glycaemic index (GI) foods are known to minimize large fluctuations in blood glucose levels and have been suggested to increase fat oxidation. The objective of this study was to simultaneously investigate glucose excursion and substrate oxidation in a whole body calorimetre when Chinese male subjects were provided a low or high GI meal. In a randomized, controlled crossover non blind design, 12 healthy Chinese male adults (BMI 21.8 ± 1.3 kgm -2 ) attended two sessions consisting of either four low or high glycaemic meals (LGI vs HGI). Breakfast, lunch and snack were consumed in a whole body calorimetre while dinner was consumed at home. Daily changes in glycaemic response (GR) and postprandial GR responses were measured using a continuous glucose monitoring system. The GR was further calculated to obtain the incremental area under the curve (iAUC) for glucose concentrations. Glycaemic variability was calculated as mean amplitude of glycaemic excursion (MAGE). Substrate oxidation was calculated by measuring respiratory quotient and urine nitrogen excretion. After LGI meals in the whole body calorimetre, iAUC for glucose (P = 0.008) was lower compared to the HGI session. The HGI treatment produced a significantly greater MAGE than the LGI treatment over the 24 hour period (P fat oxidation and lower carbohydrate oxidation were observed following breakfast and lunch when comparing LGI to HGI (P fat oxidation over carbohydrate oxidation when compared to HGI mixed meals. The consumption of low GI meals may be a strategic approach in improving overall glycaemia and increasing fat oxidation in Asians consuming a high carbohydrate diet.
Gan, Lei; Zhang, Chunxia; Shangguan, Fangqin; Li, Xiuping
2012-06-01
The continuous cooling crystallization of a blast furnace slag was studied by the application of the differential scanning calorimetry (DSC) method. A kinetic model describing the correlation between the evolution of the degree of crystallization with time was obtained. Bulk cooling experiments of the molten slag coupled with numerical simulation of heat transfer were conducted to validate the results of the DSC methods. The degrees of crystallization of the samples from the bulk cooling experiments were estimated by means of the X-ray diffraction (XRD) and the DSC method. It was found that the results from the DSC cooling and bulk cooling experiments are in good agreement. The continuous cooling transformation (CCT) diagram of the blast furnace slag was constructed according to crystallization kinetic model and experimental data. The obtained CCT diagram characterizes with two crystallization noses at different temperature ranges.
Directory of Open Access Journals (Sweden)
Ion Dranca
2011-12-01
Full Text Available This research has been carried out in order to demonstrate the use of differential scanning calorimetry (DSC in detecting and measuring α- and β-relaxation processes in amorphous pharmaceutical systems. DSC has been employed to study amorphous samples of poly (vinylpyrrolidone (PVP, indomethacin (InM, and ursodeoxycholic acid (UDA that are annealed at temperature (Ta around 0.8 of their glass transition temperature (Tg. Dynamic mechanical analysis (DMA is used to measure β- relaxation in PVP. Yet, the DSC has been used to study the glassy indomethacin aged at 0 and -10 oC for periods of time up to 109 and 210 days respectively. The results demonstrate the emergence of a small melting peak of the α-polymorph after aging for 69 days at 0°C and for 147 days at -10°C (i.e., ~55°C below the glass transition temperature that provides evidence of nucleation occurring in the temperature region of the β-relaxation.
Verevkin, Sergey P; Emel'yanenko, Vladimir N; Zaitsau, Dzmitry H; Ralys, Ricardas V; Schick, Christoph
2012-04-12
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.
Calorimetric investigation into interaction in Zr0.8Ti0.2CrFe-H2 system
International Nuclear Information System (INIS)
Sirotina, R.A.; Verbetskij, V.N.
1993-01-01
For studying Zr 0.8 Ti 0.2 CrFe-H 2 system is applied the calorimetric method with usage of the Tian-Calve type calorimeter. It is shown that up to 488 K in the system there are three characteristic regions: α (hydrogen solution in an intermetallic compounds (IMC)), β (hydrogen solution in a hydride) and α + β (region of coexistence of two phases). Temperature 448 K is near to critical one, when exceeding of which exists only hydrogen solution in a metal matrix. Pressure dependence of hydrogen content in IMC is described satisfactorily by a linear equation
Caracterização físico-química do óleo essencial da Siparuna guianensis Aublet
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Augustus Caeser Franke Portella
2014-06-01
Full Text Available Thermal and spectroscopic analyses of essential oil extracted from Siparuna guianensis Aublet, an aromatic plant belonging to medicinal ethnobotany family Siparunaceae, were carried out. The plant is known throughout the North and Northeast of Brazil by the name negramina and has wide application as a natural insect repellent. Thermogravimetric analyses were correlated with the Arrhenius Equation to provide kinetic parameters of evaporation, including activation energy and frequency factor. Differential scanning calorimetric analysis showed the presence of an exothermic oxidation peak, probably as a result of transformations and decomposition of the solid structure before melting.
International Nuclear Information System (INIS)
Bou-Abdallah, Fadi; Sprague, Samuel E.; Smith, Britannia M.; Giffune, Thomas R.
2016-01-01
Highlights: • The binding affinity of Diclofenac and Naproxen to BSA and HSA is on the order of 10 4 –10 6 M −1 . • Two Diclofenac molecules bind per BSA or HSA but only 0.75 and 3 Naproxen molecules bind to BSA and HSA, respectively. • Drugs binding to BSA is only enthalpically favored and both enthalpically and entropically favored for HSA. • Fluorescence quenching data suggest dynamic collisions and the formation of ground-state protein-drug complexes. • DSC data show multiple sequential unfolding events and strong drug stabilization effects. - Abstract: Serum albumins are ubiquitous proteins able to bind a variety of exogenous and endogenous ligands including hydrophobic pharmaceuticals. Most drugs bind to two very active binding regions located within sub-domains IIA and IIIA of the protein, also known as Sudlow’s sites. The drug binding mode of serum albumin provides important pharmacological information and influences drug solubility, efficacy, biological distribution, and excretion. Here, the binding thermodynamics of Diclofenac and Naproxen, two non-steroidal anti-inflammatory drugs (NSAIDs) to bovine and human serum albumins (BSA and HSA, respectively) were studied by isothermal titration calorimetry (ITC), fluorescence spectroscopy and differential scanning calorimetry (DSC). The ITC data show that the binding affinity (K) of Diclofenac to BSA and HSA is on the order of 10 4 M −1 with a binding stoichiometry (n) of 2 drug molecules per protein. Naproxen binding to the two proteins exhibits a different profile with K and n values on the order of 10 6 M −1 and 0.75 for BSA, and 10 5 M −1 and 3 for HSA, respectively. The binding of the two drugs to HSA is found to be both enthalpically and entropically favored suggesting the formation of hydrogen bonds and van der Waals hydrophobic effects. Binding of the two drugs to BSA is only enthalpically favored with an unfavorable entropy term. Significant enthalpy–entropy compensation
Bone scan in diagnosis of infectious osteoarthritis
International Nuclear Information System (INIS)
Marandian, M.H.; Mortazavi, H.; Behvad, A.; Haghigat, H.; Lessani, M.; Youssefian, B.
1979-01-01
Bone scan with Technetium 99m is harmless method of evaluation of skeletal lesions. It is safe in pediatrics age group and it can be used in early diagnosis of infectious osteoarthritis. Bone scan differentiate osteomyelitis from cellulitis, and also it may help in diagnosis of subclinical involvement of rheumatoid arthritis, benign and malignant bone tumors, stress fractures and periostitis. We report results of bone scan in 30 pediatrics patients as follow: osteomyelitis 9 cases, cellulitis 4 cases, infectious arthritis 7 cases, tuberculous osteoarthritis 2 cases, rheumatoid arthritis 2 cases, and other different diseases 9 cases [fr
International Nuclear Information System (INIS)
Mas, P.; Sciers, P.; Droulers, Y.
1962-01-01
Calorimetric methods may be used to measure gamma fluxes greater than 10 6 r/h near the cores of swimming pool reactors. The theory, design, and properties of isothermal calorimeters are discussed, and experimental results obtained with two types are presented. Measurement of energy deposition in materials and the long term integration of energy depositions are other uses of these devices. Results of measurements on heat deposition in steel and water are given. Fluxes were also measured. (authors) [fr
International Nuclear Information System (INIS)
Barreneche, Camila; Solé, Aran; Miró, Laia; Martorell, Ingrid; Cabeza, Luisa F; Fernández, A Inés
2012-01-01
Nowadays, thermal comfort needs in buildings have led to an increase in energy consumption of the residential and service sectors. For this reason, thermal energy storage is shown as an alternative to achieve reduction of this high consumption. Phase change materials (PCM) have been studied to store energy due to their high storage capacity. A polymeric material capable of macroencapsulating PCM was developed by the authors of this paper. However, difficulties were found while measuring the thermal properties of these materials by differential scanning calorimetry (DSC). The polymeric matrix interferes in the detection of PCM properties by DSC. To remove this interfering effect, a new methodology which replaces the conventional empty crucible used as a reference in the DSC analysis by crucibles composed of the polymeric matrix was developed. Thus, a clear signal from the PCM is obtained by subtracting the new full crucible signal from the sample signal. (paper)
Calorimetric and computational study of 7-hydroxycoumarin
International Nuclear Information System (INIS)
Sousa, Clara C.S.; Matos, M. Agostinha R.; Morais, Victor M.F.
2011-01-01
Highlights: → Experimental standard molar enthalpies of formation, sublimation of 7-hydroxycoumarin. → Combustion calorimetry, sublimation microcalorimetry, differential scanning calorimetry. → DFT calculations, MC3BB and MC3MPW methods have been performed for the compound and its isomers. → Computational estimation of enthalpies of formation of 5-, 6-, and 8-hydroxycoumarin. - Abstract: The standard (p o = 0.1 MPa) molar energy of combustion in oxygen, at T = 298.15 K, of 7-hydroxycoumarin was measured by static bomb calorimetry. The value of the standard molar enthalpy of sublimation was obtained by Calvet microcalorimetry and corrected to T = 298.15 K. Combining these results, the standard molar enthalpy of formation of the compound, in the gas phase, at T = 298.15 K, has been calculated, -(337.5 ± 2.3) kJ . mol -1 . The values for the temperature of fusion, T fusion , and for the fusion enthalpy, at T = T fusion , are also reported. Additionally, high-level density functional theory calculations using the B3LYP hybrid exchange-correlation energy functional with extended basis sets, the MC3BB and MC3MPW methods and more accurate correlated computational techniques of the MCCM suite have been performed for the compound. The agreement between experiment and theory gives confidence to estimate the enthalpy of formation of the remaining hydroxycoumarins substituted in the benzene ring.
Paulechka, Yauheni U; Kabo, Andrey G; Blokhin, Andrey V
2009-11-05
The enthalpy of the 1-butyl-3-methylimidazolium bromide [C(4)mim]Br ionic liquid synthesis reaction 1-methylimidazole (liq) + 1-bromobutane (liq) --> [C(4)mim]Br (liq) was determined in a homemade small-volume isoperibol calorimeter to be Delta(r)H degrees (298) = -87.7 +/- 1.6 kJ x mol(-1). The activation energy for this reaction in a homogeneous system E(A) = 73 +/- 4 kJ x mol(-1) was found from the results of calorimetric measurements. The formation enthalpies for the crystalline and liquid [C(4)mim]Br were determined from the calorimetric data: Delta(f)H degrees (298)(cr) = -178 +/- 5 kJ x mol(-1) and Delta(f)H degrees (298)(liq) = -158 +/- 5 kJ x mol(-1). The ideal-gas formation enthalpy of this compound Delta(f)H degrees (298)(g) = 16 +/- 7 kJ x mol(-1) was calculated using the methods of quantum chemistry and statistical thermodynamics. The vaporization enthalpy of [C(4)mim]Br, Delta(vap)H degrees (298) = 174 +/- 9 kJ x mol(-1), was estimated from the experimental and calculated formation enthalpies. It was demonstrated that vapor pressure of this ionic liquid cannot be experimentally determined.
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Nichola C Garbett
Full Text Available Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN and extent of spread of invasive carcinomas of the cervix (IC are needed. Differential scanning calorimetry (DSC has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate
Garbett, Nichola C; Merchant, Michael L; Helm, C William; Jenson, Alfred B; Klein, Jon B; Chaires, Jonathan B
2014-01-01
Improved methods for the accurate identification of both the presence and severity of cervical intraepithelial neoplasia (CIN) and extent of spread of invasive carcinomas of the cervix (IC) are needed. Differential scanning calorimetry (DSC) has recently been shown to detect specific changes in the thermal behavior of blood plasma proteins in several diseases. This methodology is being explored to provide a complementary approach for screening of cervical disease. The present study evaluated the utility of DSC in differentiating between healthy controls, increasing severity of CIN and early and advanced IC. Significant discrimination was apparent relative to the extent of disease with no clear effect of demographic factors such as age, ethnicity, smoking status and parity. Of most clinical relevance, there was strong differentiation of CIN from healthy controls and IC, and amongst patients with IC between FIGO Stage I and advanced cancer. The observed disease-specific changes in DSC profiles (thermograms) were hypothesized to reflect differential expression of disease biomarkers that subsequently bound to and affected the thermal behavior of the most abundant plasma proteins. The effect of interacting biomarkers can be inferred from the modulation of thermograms but cannot be directly identified by DSC. To investigate the nature of the proposed interactions, mass spectrometry (MS) analyses were employed. Quantitative assessment of the low molecular weight protein fragments of plasma and urine samples revealed a small list of peptides whose abundance was correlated with the extent of cervical disease, with the most striking plasma peptidome data supporting the interactome theory of peptide portioning to abundant plasma proteins. The combined DSC and MS approach in this study was successful in identifying unique biomarker signatures for cervical cancer and demonstrated the utility of DSC plasma profiles as a complementary diagnostic tool to evaluate cervical cancer
International Nuclear Information System (INIS)
Hasan, A.; McCormack, S.J.; Huang, M.J.; Norton, B.
2014-01-01
Highlights: • Five PCM are characterized using tow techniques for PV temperature regulation. • Thermophysical properties of interest are determined and compared with literature. • Determined PCM properties are discussed as criteria for PV temperature regulation. • One PCM identified as potential candidate for PV temperature regulation. - Abstract: Five solid–liquid phase change materials comprising three basic classes, paraffin waxes, salt hydrates and mixtures of fatty acids were thermophysically characterized for thermal regulation applications in photovoltaics. The PCM were investigated using Differential Scanning Calorimetry and Temperature History Method to find their thermophysical properties of interest. The relationship between thermophysical properties of the PCM and their choice as temperature regulators in photovoltaics is discussed in relation to the ambient conditions under which PV systems operate
Kharakoz, Dmitry P; Panchelyuga, Maria S; Tiktopulo, Elizaveta I; Shlyapnikova, Elena A
2007-12-01
Chain-ordering/melting transition in a series of saturated diacylphosphatidylcholines (PCs) in aqueous dispersions have been studied experimentally (calorimetric and ultrasonic techniques) and theoretically (an Ising-like lattice model). The shape of the calorimetric curves was compared with the theoretical data and interpreted in terms of the lateral interactions and critical temperatures determined for each lipid studied. A critical chain length has been found (between 16 and 17 C-atoms per chain) which subdivides PCs into two classes with different phase behavior. In shorter lipids, the transition takes place above their critical temperatures meaning that this is an intrinsically continuous transition. In longer lipids, the transition occurs below the critical temperatures of the lipids, meaning that the transition is intrinsically discontinuous (first-order). This conclusion was supported independently by the ultrasonic relaxation sensitive to density fluctuations. Interestingly, it is this length that is the most abundant among the saturated chains in biological membranes.
DEFF Research Database (Denmark)
Pedersen, T.B.; Kaasgaard, Thomas; Jensen, M.O.
2005-01-01
The thermotropic phase behavior and lateral structure of dipalmitoylphosphatidylcholine (DPPC) lipid bilayers containing an acylated peptide has been characterized by differential scanning calorimetry (DSC) on vesicles and atomic force microscopy (AFM) on mica-supported bilayers. The acylated...... peptide, which is a synthetic decapeptide N-terminally linked to a C-14 acyl chain (C-14-peptide), is incorporated into DPPC bilayers in amounts ranging from 0-20 mol %. The calorimetric scans of the two-component system demonstrate a distinct influence of the C-14-peptide on the lipid bilayer...... gel phase DPPC bilayers, inserts preferentially into preexisting defect regions and has a noticeable influence on the organization of the surrounding lipids. The presence of the C-14-peptide gives rise to a laterally heterogeneous bilayer structure with coexisting lipid domains characterized by a 10...
International Nuclear Information System (INIS)
Woolley, E.M.
2007-01-01
The development of fixed twin cell temperature scanning calorimeters has enabled the more efficient determination of heat capacities of dilute aqueous solutions with a precision comparable to that of the Picker flow heat capacity calorimeters developed nearly 40 years ago. Experiments require less than 0.5 cm 3 of solution, and results can be obtained routinely over the temperature range (278 to 395) K at pressures up to a few bars. Multiple scanning of samples by both increasing and decreasing temperature allows assessment of instrument drift, solute stability, and reproducibility of results. Chemical calibration is essential to take full advantage of the precision and sensitivity of the calorimeters. The calorimetric output is a direct measure of the difference in heat capacity per unit volume of a solution and of a reference liquid, usually water. Thus, densities of the solution and reference liquid are needed to transform the results into heat capacities per unit mass of solution. Examples of solutes that have been investigated include a variety of inorganic and organic compounds that dissolve to give simple ionic or neutral species, or that produce complexes or species that exist in equilibrium distributions that can change as the temperature is scanned. Appropriate selection of the results from experiments on combinations of solutes allows calculation of standard state (zero concentration) thermodynamic quantities for chemical processes and reactions over the ranges of temperature scanned at the solution compositions investigated. Results for a few specific systems are presented and discussed for some representative classes of solutes that have been investigated in our laboratory since 1998
Electron energy and charge albedos - calorimetric measurement vs Monte Carlo theory
International Nuclear Information System (INIS)
Lockwood, G.J.; Ruggles, L.E.; Miller, G.H.; Halbleib, J.A.
1981-11-01
A new calorimetric method has been employed to obtain saturated electron energy albedos for Be, C, Al, Ti, Mo, Ta, U, and UO 2 over the range of incident energies from 0.1 to 1.0 MeV. The technique was so designed to permit the simultaneous measurement of saturated charge albedos. In the cases of C, Al, Ta, and U the measurements were extended down to about 0.025 MeV. The angle of incidence was varied from 0 0 (normal) to 75 0 in steps of 15 0 , with selected measurements at 82.5 0 in Be and C. In each case, state-of-the-art predictions were obtained from a Monte Carlo model. The generally good agreement between theory and experiment over this extensive parameter space represents a strong validation of both the theoretical model and the new experimental method. Nevertheless, certain discrepancies at low incident energies, especially in high-atomic-number materials, and at all energies in the case of the U energy albedos are not completely understood
Energy Technology Data Exchange (ETDEWEB)
Rossi, F.; Lambertin, M. [Arts et Metiers ParisTech, LaBoMaP, Cluny (France); Delfaut-Durut, L. [CEA, Centre de Valduc, (SEMP, LECM), Is-sur-Tille (France); Maitre, A. [SPCTS, UFR Sciences et techniques, Limoges (France); Vilasi, M. [LCSM, Univ. Nancy I, Vandoeuvre les Nancy (France)
2010-02-15
Transformations undergone by lead-calcium alloys are numerous and have different kinetics from a few minutes to a few years. Anisothermal calorimetric measurements were performed to be able to identify these transformations quickly. It was then possible to identify five transformations. Complementary measurements have enabled us to define transformations with an in-situ electrical resistance measurement to follow the evolution of the calcium in solid solution and with an in-situ hardness measurement to characterise the mechanical properties. The aim of these results is to simulate the ageing and overageing of the alloy in isothermal conditions. (orig.)
Knopp, Matthias Manne; Löbmann, Korbinian; Elder, David P; Rades, Thomas; Holm, René
2016-05-25
Differential scanning calorimetry (DSC) is frequently the thermal analysis technique of choice within preformulation and formulation sciences because of its ability to provide detailed information about both the physical and energetic properties of a substance and/or formulation. However, conventional DSC has shortcomings with respect to weak transitions and overlapping events, which could be solved by the use of the more sophisticated modulated DSC (mDSC). mDSC has multiple potential applications within the pharmaceutical field and the present review provides an up-to-date overview of these applications. It is aimed to serve as a broad introduction to newcomers, and also as a valuable reference for those already practising in the field. Complex mDSC was introduced more than two decades ago and has been an important tool for the quantification of amorphous materials and development of freeze-dried formulations. However, as discussed in the present review, a number of other potential applications could also be relevant for the pharmaceutical scientist. Copyright © 2015 Elsevier B.V. All rights reserved.
Sun, Xiaoqin; Lee, Kyoung Ok; Medina, Mario A.; Chu, Youhong; Li, Chuanchang
2018-06-01
Differential scanning calorimetry (DSC) analysis is a standard thermal analysis technique used to determine the phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy of phase change materials (PCMs). To determine the appropriate heating rate and sample mass, various DSC measurements were carried out using two kinds of PCMs, namely N-octadecane paraffin and calcium chloride hexahydrate. The variations in phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy were observed within applicable heating rates and sample masses. It was found that the phase transition temperature range increased with increasing heating rate and sample mass; while the heat of fusion varied without any established pattern. The specific heat decreased with the increase of heating rate and sample mass. For accuracy purpose, it is recommended that for PCMs with high thermal conductivity (e.g. hydrated salt) the focus will be on heating rate rather than sample mass.
van Leenders, G; Dijkman, H; Hulsbergen-van de Kaa, C; Ruiter, D; Schalken, J
2000-08-01
In human prostate epithelium, morphologically basal and luminal cells can be discriminated. The basal cell layer that putatively contains progenitor cells of the secretory epithelium is characterized by the expression of keratins (K) 5 and 14. Luminal cells represent the secretory compartment of the epithelium and express K8 and 18. We developed a technique for the simultaneous analysis of K5, 14, and 18 to identify intermediate cell stages in the prostate epithelium and to study the dynamic aspects of its differentiation in vitro. Nonmalignant prostate tissue and primary epithelial cultures were immunohistochemically characterized using triple staining with antibodies for K5, K14, and K18. Antibodies for K18 and K5 were conjugated directly with fluorochromes Alexa 488 and 546. K14 was visualized indirectly with streptavidin-Cy5. Keratin expression was analyzed by confocal scanning microscopy. The occurrence of exocrine and neuroendocrine differentiation in culture was determined via antibodies to prostate-specific antigen (PSA), chromogranin A, and serotonin. We found that basal cells expressed either K5(++)/14(++)/18+ or K5(++)/18+. The majority of luminal cells expressed K18(++), but colocalization of K5+/18(++) were recognized. Epithelial monolayer cultures predominantly revealed the basal cell phenotype K5(++)/14(++)/18+, whereas intermediate subpopulations expressing K5+/14+/18(++) and K5+/18(++) were also identified. On confluence, differentiation was induced as multicellular gland-like buds, and extensions became evident on top of the monolayer. These structures were composed of K18(++)- and K5+/18(+)-positive cell clusters surrounded by phenotypically basal cells. Few multicellular structures and cells in the monolayer showed exocrine differentiation (PSA+), but expression of chromogranin A and serotonin was absent. We conclude that simultaneous evaluation of keratin expression is useful for analyzing epithelial differentiation in the prostate. During this
Calorimetric and ionometric dosimetry for cyclotron produced fast neutrons
International Nuclear Information System (INIS)
McDonald, J.C.; Ma, I.C.; Laughlin, J.S.
1977-01-01
A portable tissue equivalent (TE) calorimeter, constructed of A-150 plastic, has been employed for the measurement of absorbed dose in two fast neutron fields produced by the 9 Be( 3 He,n) and 9 Be(d,n) interactions. A disc shaped ionization chamber has also been constructed of A-150 plastic and has a collecting volume geometrically equivalent to the calorimeter core (2 cm in diameter and 0.2 cm thick). A flow of methane compounded TE gas was maintained through the chamber at a rate of approximately 5 cc/min during the measurements. The ionization chamber was mounted within an irradiation enclosure which simulated the outer dimensions of the calorimeter housing. In this way, both detectors were placed at the same depth in TE plastic and each received approximately the same scattered radiation. The gamma-ray component of absorbed dose has been determined by the use of a miniature Geiger-Mueller dosimeter. It was found that the response sensitivity ratio for the TE ionization chamber in the two neutron fields relative to the 60 Co gamma-ray field, when normalized to the absorbed dose measured by the TE calorimeter, was approximately 1.07. Uncertainties in these calorimetric and ionometric methods for the measurements of the absorbed dose will be discussed along with measurements of the thermal defect for A-150 TE plastic
Energy Technology Data Exchange (ETDEWEB)
Taniguchi, H.; Masuda, T.; Tsutsumi, K.; Takahashi, H.
1978-07-01
Comparison of the calorimetric titration method with the amine titration method for the determination of acid strength distribution of the silica-alumina surface was carried out for a catalyst containing 13% by wt alumina and evacuated at 400/sup 0/C at 0.00001 mm Hg for five hours. The heats of adsorption of ammonia on silica-alumina poisoned with Hammett indicators of 8.2 to 3.3 pK/sub a/ were also measured to obtain the relation between the dissociation constant of the acid (pK/sub a/) and the heat of adsorption. At pK/sub a/ values of -5.6 and +3.3, the differential heats of adsorption were 76.1 and 55.1 kj/mole, respectively. The number of acid sites calculated from the heat vs. adsorbed-amount curve was about twice as large as that determined by amine titration. The discrepancy is discussed.
Importance of 241 Am Determination in the Characterization of PuO2 Standards for Calorimetric Assay.
Energy Technology Data Exchange (ETDEWEB)
Sampson, Thomas E.
2005-01-01
Plutonium dioxide (PuO{sub 2}) standards are often used both as heat standards and isotopic standards for calorimetric assay. Calorimetric assay is the combination of the power in watts measured in a calorimeter with the effective specific power (P{sub eff}) in watts/g Pu, determined either by nondestructive gamma-ray assay or by destructive mass spectrometry, to yield the total elemental plutonium mass in the sample. To use a PuO{sub 2} sample as a heat standard for calorimetry, one must determine both the plutonium mass and P{sub eff} with very small uncertainties and then calculate the sample watts from the known plutonium mass, specific powers, and isotopic composition. Well-characterized PuO{sub 2} standards have plutonium mass values determined by analytical chemistry with a precision and accuracy on the order of 0.1%-0.2% relative to the total mass of the sample. Mass spectrometry, typically used to determine the isotopic fractions of plutonium standards, is very accurate and precise for the major isotopes but is somewhat less precise for low-abundance isotopes. The characterization of the {sup 241}Am/Pu ratio in the standard is also of great importance because {sup 241}Am can contribute significantly to P{sub eff} and to the heat output of the standard. The determination of the {sup 241}Am/Pu ratio in a plutonium-bearing sample is a process that is less standardized than mass spectrometry. There are no certified reference materials (CRMs) traceable to the national measurement system for {sup 241}Am in plutonium, and routine analytical {sup 241}Am/Pu ratio measurements often exhibit uncertainties of several percent relative to the total plutonium or greater.
Directory of Open Access Journals (Sweden)
RLM. Satrio Ari Wibowo
2015-12-01
Full Text Available The aim of this study was to determine the effect of the skin preservation type against shrinkage temperature of leather. The material used in this study was the skin of pufferfish (Arothon reticularis that have been preserved by salting, formaldehyde and pickling and also raw skin as a reference. The method used to measure the shrinkage temperature was thermal analysis using Differential Scanning Calorimeter (DSC that operated from 4°C up to 440°C with nitrogen stream. DSC measurement results showed that shrinkage temperature of puffer fish preserved with formaldehyde was higher than salting and pickling, which is 63.64°C; 47.95°C; 57.37oC respectively. The advantage of using formaldehyde compared to others preservation technique was not only can protect the skin from damage by microorganisms, but also can create a bond with the collagen .
Schubnell, M; Schawe, J E
2001-04-17
In differential scanning calorimetry (DSC), remnant moisture loss in samples often overlaps and distorts other thermal events, e.g. glass transitions. To separate such overlapping processes, temperature modulated DSC (TMDSC) has been widely used. In this contribution we discuss the quantitative determination of the heat capacity of a moist sample from TMDSC measurements. The sample was a spray-dried pharmaceutical compound run in different pans (hermetically-sealed pan, pierced lid pan [50 microm] and open pan). The apparent heat capacity was corrected for the remaining amount of moisture. Using this procedure we could clearly identify the glass transition of the dry and the moist sample. We found that a moisture content of about 6.2% shifts the glass transition by about 50 degrees C.
Badkar, Aniket; Yohannes, Paulos; Banga, Ajay
2006-02-17
The objective of this study was to evaluate the feasibility of using T(ZERO) modulated temperature differential scanning calorimetry (MDSC) as a novel technique to characterize protein solutions using lysozyme as a model protein and IgG as a model monoclonal antibody. MDSC involves the application of modulated heating program, along with the standard heating program that enables the separation of overlapping thermal transitions. Although characterization of unfolding transitions for protein solutions requires the application of high sensitive DSC, separation of overlapping transitions like aggregation and other exothermic events may be possible only by use of MDSC. A newer T(ZERO) calibrated MDSC model from TA instruments that has improved sensitivity than previous models was used. MDSC analysis showed total, reversing and non-reversing heat flow signals. Total heat flow signals showed a combination of melting endotherms and overlapping exothermic events. Under the operating conditions used, the melting endotherms were seen in reversing heat flow signal while the exothermic events were seen in non-reversing heat flow signal. This enabled the separation of overlapping thermal transitions, improved data analysis and decreased baseline noise. MDSC was used here for characterization of lysozyme solutions, but its feasibility for characterizing therapeutic protein solutions needs further assessment.
International Nuclear Information System (INIS)
Ganelina, E.Sh.; Borgoyakov, S.A.
1985-01-01
Interaction of phosphorotungstenvanadium heteropolyacids (HPA) with alkali (NaOH) is studied by the methods of calorimetric and potentiometric titration. Three stages are singled out: 1) neutralization of ''strong'' hydrogen atoms with a constant thermal effect of 52.0+-1.6 kJ/mol; 2) neutralization of ''weak'' protons, which acidity constant is of order 10 -2 ; 3) interaction of NaOH with hydrogen atoms combined with the internal sphere of HPA, and completed by HPA destruction. The data obtained are compared with the results, calculating the composition of polymer particles inside HPA, and they are discussed from the view point of their micellar structure
Directory of Open Access Journals (Sweden)
O. C. Vorster
2004-09-01
Full Text Available
Die studie van die verhardingsreaksiekinetika van deklae word bemoeilik deur die aanwesigheid van vlugtige stowwe, pigmente en bypigmente. In hierdie studie word die verhardingsreaksiekinetika van ’n karboksielgetermineerde poliëstertriglisediel-isosianuraat deur middel van parallelplaatspanningsreometrie bepaal. Jeltye is verkry en skaleringseksponente bepaal. ’n Nuwe metode vir die voorspelling van die verloop van die reaksie word voorgestel en vergelyk met resultate verkry deur middel van differensiël skanderingskalorimetrie.
Abstract
The use of a rheological technique in the determination of the curing kinetics of a reactive polyester powder coating
In this article a study of the curing process of carboxyl terminated polyester-triglycidyl isocyanurate systems is reported. A comparison is made between the generally used Differential Scanning Calorimetric methods and rheokinetic methods, using a parallel plate oscillating stress rheometer. Gel times were determined and scaling exponents calculated. A new method for the estimation of the extent of reaction is presented and compared with results obtained by means of differential scanning calorimetry
Environmental scanning as information seeking and organizational learning
Directory of Open Access Journals (Sweden)
2001-01-01
Full Text Available Environmental scanning is the acquisition and use of information about events, trends, and relationships in an organization's external environment, the knowledge of which would assist management in planning the organization's future course of action. Depending on the organization's beliefs about environmental analyzability and the extent that it intrudes into the environment to understand it, four modes of scanning may be differentiated: undirected viewing, conditioned viewing, enacting, and searching. We analyze each mode of scanning by examining its characteristic information needs, information seeking, and information use behaviours. In addition, we analyze organizational learning processes by considering the sensemaking, knowledge creating and decision making processes at work in each mode.
Directory of Open Access Journals (Sweden)
Gernot K.-H. Kolb
2016-08-01
Full Text Available Al-Zn-Mg-Cu alloys are widely used in aircraft applications because of their superior mechanical properties and strength/weight ratios. Commercial Al-Zn-Mg-Cu alloys have been intensively studied over the last few decades. However, well-considered thermodynamic calculations, via the CALPHAD approach, on a variation of alloying elements can guide the fine-tuning of known alloy systems and the development of optimized heat treatments. In this study, a comparison was made of the solidus temperatures of different Al-Zn-Mg-Cu alloys determined from thermodynamic predictions and differential scanning calorimetry (DSC measurements. A variation of the main alloying elements Zn, Mg, and Cu generated 38 experimentally produced alloys. An experimental determination of the solidus temperature via DSC was carried out according to a user-defined method, because the broad melting interval present in Al-Zn-Mg-Cu alloys does not allow the use of the classical onset method for pure substances. The software algorithms implemented in FactSage®, Pandat™, and MatCalc with corresponding commercially available databases were deployed for thermodynamic predictions. Based on these investigations, the predictive power of the commercially available CALPHAD databases and software packages was critically reviewed.
Luo, Dawei; Han, Xu; He, Liqun; Cui, Xiangdong; Cheng, Shuxia; Lu, Caicheng; Liu, Jianghan; Gao, Dayong
2002-01-01
A modified analytical and experimental method using differential scanning calorimeter (DSC) was developed to determine the cell volume change during the freezing process. Two cell types were used in the study: human platelets and erythrocytes (red blood cells). Isotonic cell suspensions with different cytocrits were prepared and used in the DSC experiments. Low cooling rates were used to avoid intracellular ice formation. Cell suspensions were cooled from room temperature to -40 degrees C. Latent heat release from the freezing of cell suspensions was shown to be a linear function of cytocrit. From slope and intercept of the linear function, cell volume change was determined based on a developed theoretical model. From experimental data and theoretical analyses, it was revealed that (a) the final volume of a human platelet at -40 degrees C was 33.7% of its isotonic volume, and 15.2% of the original (at isotonic condition) intracellular water remained unfrozen inside platelets, and (b) the final volume of human erythrocyte at -40 degrees C was 50.0% of its isotonic volume, and 30.3% of the original intracellular water was kept inside cells as residual unfrozen water.
Dobrzyńska-Mizera, Monika; Dutkiewicz, Michał; Sterzyński, Tomasz; Di Lorenzo, Maria Laura
2015-12-01
Composites based on polypropylene (iPP) modified with a sorbitol derivative (NX8000) and siloxane-silsesquioxane resin (SiOPh) containing maleated polypropylene (MAPP) as compatibilizer were prepared by melt extrusion. Calorimetric investigations were carried out using differential scanning calorimetry (DSC), whereas the morphological and mechanical properties were investigated by scanning electron microscopy (SEM) and static tensile tests. DSC measurements revealed no influence of SiOPh and a slight effect of MAPP addition on the crystallization kinetics of polypropylene. Additionally, the introduction of MAPP into the iPP+NX8000+SiOPh composites increased plastic properties of the samples. All the above was attributed to the compatibilizing effect of MAPP which improved interfacial adhesion between iPP, NX8000 and SiOPh. This phenomenon was also confirmed by the SEM images illustrating more homogenous distribution of the filler in the compatibilized samples.
Radiation scanning aids tower diagnosis at Arun LNG plant
International Nuclear Information System (INIS)
Naklie, M.M.; Pless, L.; Gurning, T.P.; Hyasak, M.
1990-01-01
Radiation scanning has been used effectively to troubleshoot the treating towers of the Arun LNG plant in Sumatra, Indonesia. The plant is one of the world's largest such facilities. The analysis was part of an investigation aimed at increasing the capacity of the treater section of the plant. Radiation scanning is a tool which, in addition to tower differential pressure and product purity, can aid in diagnosing tower performance
Computed tomography scans of metastatic hepatic tumors
Energy Technology Data Exchange (ETDEWEB)
Takemoto, Kazumasa; Fukuda, Haruyuki; Nemoto, Yutaka [Osaka City Univ. (Japan). Faculty of Medicine
1984-01-01
Computed tomography scans of 114 metastatic hepatic tumors were reviewed. Central low density was found in 82 cases (71.9%) and seems to be characteristic to metastatic hepatic tumors. Dynamic CT was performed on 34 cases, and 21 (61.8%) of these had ring enhancement at the arterial phase. Most of metastatic hepatic tumors could be differentiated from hepatocellular carcinoma. However, metastatic hepatic tumors from renal cell carcinoma, renal rhabdomyosarcoma, malignant melanoma and leiomyosarcoma could not be differentiated from hepatocellular carcinoma, even with use of dynamic study.
Energy Technology Data Exchange (ETDEWEB)
Godinho, K.O.; Silva, A.G.P.; Holanda, J.N.F. [Universidade Estadual do Norte Fluminense (LAMAV/UENF), Campos dos Goytacazes, RJ (Brazil). Grupo de Materiais Ceramicos], Email: holanda@uenf.br
2010-07-01
Phase change materials for heat storage are used as passive solar energy storage materials, which can be impregnated into construction materials. In this work the thermal stability (heating/cooling cycle) of the paraffin wax was investigated using differential scanning calorimetry. The latent heat and fusion temperature were determined for the following thermal cycles: 0, 30, 180 and 360. The thermal stability for paraffin wax infiltrated in support of gypsum was also determined. The experimental results showed that the paraffin wax showed good thermal stability in the states pure and infiltrated for up to 360 thermal cycles. (author)
Development of a calorimetric system for electron beam dosimetry in radiation processing
International Nuclear Information System (INIS)
Banados P, H.E.
1994-01-01
A calorimetric system for electron beam dosimetry in radiation processing was developed. The system is composed of a graphite core calorimeter, the temperature measuring and electrical calibrating instrumentation, a microcomputer and the software for the system automation. The research aimed at the optimization of the project parameters, the development of advanced methodologies for calibrating the temperature sensor, the determination of the thermal capacity as a function of the temperature, the measurement of the absorbed dose, and the development of the software needed for the system operation. The operating range extends from 0.1 kGy to 30 kGy. The uncertainty in the measurement of the absorbed dose was estimated to be ± 1.8% at the 95% confidence level. Comparative tests of the absorbed dose measurements were made using the IPEN electron accelerator. The results obtained showed an excellent agreement between the absorbed dose determined by the calorimeter and the absorbed dose calculated from the nominal power delivered by the accelerator. (author). 67 refs, 63 figs, 2 tabs
Abdominal lymphadenopathy in tuberculosis and lymphoma: Differentiation with CT
International Nuclear Information System (INIS)
Shin, Yong Moon; Choi, Byung Ihn; Han, Joon Koo; Han, Man Chung; Song, Chi Sung; Yang, Seoung Oh
1993-01-01
Tuberculosis and lymphoma, these 2 dieases can present with lymphadenopathy in anywhere of the body. Therefore differentiation of tuberculosis from lymphoma is often difficult. CT scans of 17 patients with tuberculosis and 23 patients with lymphoma were retrospectively reviewed to evaluate the efficacy of CT scans in differentating adenopathy between tuberculosis and lymphoma. All the patients underwent abdominal CT scans with contrast enhancement before treatment. The size, internal architecture, distribution of lymph nodes, and associated findings on CT scans were analyzed. As compared with lymphoma, tuberculous lymphadenopathy showed 1) female preponderance (65%), 2) predilection for percolative lymph nodes (47%), 3) internal low attenuation in lymph nodes (82%), 4) cold abscess formation (24%). Characteristics of lymphoma on CT scans include 1) male preponderance (78%), 2) conglomeration of lymph nodes (39%), 3) homogeneous internal lymph node structure (83%). These results suggest that evaluation of the cahracteristics of lymphadenopathy on CT scans is helpful for differentiating between tuberculousis and lymphoma
Sorption of organic chemicals at biogeochemical interfaces - calorimetric measurements
Krüger, J.; Lang, F.; Siemens, J.; Kaupenjohann, M.
2009-04-01
Biogeochemical interfaces in soil act as sorbents for organic chemicals, thereby controlling the degradation and mobility of these substances in terrestrial environments. Physicochemical properties of the organic chemicals and the sorbent determine sorptive interactions. We hypothesize that the sorption of hydrophobic organic chemicals ("R-determined" chemicals) is an entropy-driven partitioning process between the bulk aqueous phase and biogeochemical interface and that the attachment of more polar organic chemicals ("F-determined" chemicals) to mineral surfaces is due to electrostatic interactions and ligand exchange involving functional groups. In order to determine thermodynamic parameters of sorbate/sorbent interactions calorimetric titration experiments have been conducted at 20Ë C using a Nanocalorimeter (TAM III, Thermometric). Solutions of different organic substances ("R-determined" chemicals: phenanthrene, bisphenol A, "F-determined" chemicals: MCPA, bentazone) with concentrations of 100 mol l-1 were added to suspensions of pure minerals (goethite, muscovite, and kaolinite and to polygalacturonic acid (PGA) as model substance for biofilms in soil. Specific surface, porosity, N and C content, particle size and point of zero charge of the mineral were analyzed to characterize the sorbents. The obtained heat quantities for the initial injection of the organic chemicals to the goethite were 55 and 71 J for bisphenol A and phenanthrene ("R-determined representatives") and 92 and 105 J for MCPA and bentazone ("F-determined" representatives). Further experiments with muscovite, kaolinite and PGA are in progress to determine G and H of the adsorption process.
International Nuclear Information System (INIS)
Ma, C.; Wu, Z.; Wang, H.; Wang, X.; Shao, M.; Zhao, L.; Jiawei, X.
2015-01-01
Aim of the present study was to investigate the usefulness of 18 F-FDG SPECT/CT in differentiated thyroid cancer (DTC) with elevated serum thyroglobulin (Tg) but negative iodine-131 scan. This retrospective review of patients with DTC recurrence who had 18 F-FDG SPECT/CT and 18 F-FDG PET/CT for elevated serum Tg but negative iodine-131 scan (March 2007-October 2012). After total thyroidectomy followed by radioiodine ablation, 86 consecutive patients with elevated Tg levels underwent 18 F-FDG SPECT/CT or 18 F-FDG PET/CT. Of these, 45 patients had 18 F-FDG SPECT/CT, the other 41 patients had 18 F-FDG PET/CT 3-4 weeks after thyroid hormone withdrawal. The results of 18 F-FDG PET/CT and SPECT/CT were correlated with patient follow-up information, which included the results from subsequent imaging modalities such as neck ultrasound, MRI and CT, Tg levels, and histologic examination of surgical specimens. The diagnostic accuracy of the two imaging modalities was evaluated. In 18 F-FDG SPECT/CT scans, 24 (24/45) patients had positive findings, 22 true positive in 24 patients, false positive in 2 patients, true-negative and false-negative in 6, 15 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG SPECT/CT were 59.5%, 75% and 62.2%, respectively. Twenty six patients had positive findings on 18 F-FDG PET/CT scans, 23 true positive in 26 (26/41) patients, false positive in 3 patients, true-negative and false-negative in 9, 6 patients, respectively. The overall sensitivity, specificity, and accuracy of 18F-FDG PET/CT were 79.3%, 81.8% and 78.1%, respectively. Clinical management changed for 13 (29%) of 45 patients by 18 F-FDG SPECT/CT, 14 (34%) of 41 patients by 18F-FDG PET/CT including surgery, radiation therapy, or multi kinase inhibitor. Based on the retrospective analysis of 86 patients, 18F-FDG SPECT/CT has lower sensitivity in the diagnosis of DTC recurrence with elevated Tg and negative iodine-131scan to 18F-FDG PET/CT. The clinical
International Nuclear Information System (INIS)
Niden, A.H.; Mishkin, F.S.; Khurana, M.M.L.; Pick, R.
1977-01-01
Twenty-three patients with clinical signs of pulmonary embolic disease and lung infiltrates were studied to determine the value of gallium citrate 67 Ga lung scan in differentiating embolic from inflammatory lung disease. In 11 patients without angiographically proved embolism, only seven had corresponding ventilation-perfusion defects compatible with inflammatory disease. In seven of these 11 patients, the 67 Ga concentration indicated inflammatory disease. In the 12 patients with angiographically proved embolic disease, six had corresponding ventilation-perfusion defects compatible with inflammatory disease. None had an accumulation of 67 Ga in the area of pulmonary infiltrate. Thus, ventilation-perfusion lung scans are of limited value when lung infiltrates are present. In contrast, the accumulation of 67 Ga in the lung indicates an inflammatory process. Gallium imaging can help select those patients with lung infiltrates who need angiography
Dynamic computed tomography scanning of benign bone lesions: Preliminary results
International Nuclear Information System (INIS)
Levine, E.; Neff, J.R.
1983-01-01
The majority of benign bone lesions can be evaluated adequately using conventional radiologic techniques. However, it is not always possible to differentiate reliably between different types of benign bone lesions on the basis of plain film appearances alone. Dynamic computed tomography (CT) scanning provides a means for further characterizing such lesions by assessing their degree of vascularity. Thus, it may help in distinguishing an osteoid osteoma, which has a hypervascular nidus, from a Brodie's abscess, which is avascular. Dynamic CT scanning may also help in the differentiation between a fluid-containing simple bone cyst, which is avascular, and other solid or semi-solid benign bone lesions which slow varying degrees of vascularity. However, because of the additional irradiation involved, dynamic CT scanning should be reserved for evaluation of selected patients with benign bone lesions in whom the plain film findings are not definitive and in whom the CT findings may have a significant influence on management. (orig.)
Estudio de las interacciones OHÏ€ por espectroscopia infrarroja y calorimetría de solución
Directory of Open Access Journals (Sweden)
Nelly Rodríguez C.
2009-06-01
Full Text Available Se estudiaron las interacciones moleculares del tipo OH . . . Ï€ existentes entre algunos fenoles y el benceno, usando como solvente tetracloruro de carbono a 25°C, mediante calorimetría de solución y espectroscopia infrarroja. Las entalpias de formación de los complejos, calculadas por métodos calorimétricos en base a las ecuaciones de Bolles-Drago y de Lamberts-Zeegers-Huyskens y de acuerdo a los datos de constantes de equilibrio obtenidos por el método infrarrojo, resultaron ser del orden de —1 a —2 kcal/mol, valores que las sitúan entre las uniones más débiles.
Technetium phosphate bone scan in the diagnosis of septic arthritis in childhood
International Nuclear Information System (INIS)
Sundberg, S.B.; Savage, J.P.; Foster, B.K.
1989-01-01
The technetium phosphate bone scans of 106 children with suspected septic arthritis were reviewed to determine whether the bone scan can accurately differentiate septic from nonseptic arthropathy. Only 13% of children with proved septic arthritis had correct blind scan interpretation. The clinically adjusted interpretation did not identify septic arthritis in 30%. Septic arthritis was incorrectly identified in 32% of children with no evidence of septic arthritis. No statistically significant differences were noted between the scan findings in the septic and nonseptic groups and no scan findings correlated specifically with the presence or absence of joint sepsis
Gallium scanning in differentiating malignant from benign asbestos-related pleural disease
International Nuclear Information System (INIS)
Teirstein, A.S.; Chahinian, P.; Goldsmith, S.J.; Sorek, M.
1986-01-01
In order to assess the utility of 67gallium citrate in delineating malignant pleural mesothelioma from benign asbestos-related pleural disease, 49 patients with malignant mesothelioma and 16 with benign asbestos-related pleural disease were studied. Seven patients with malignant mesothelioma had no history of asbestos exposure, while the remaining 58 patients were exposed. Forty-three of the 49 patients (88%) with malignant mesothelioma had a positive 67gallium scan including 36 of the 42 (86%) patients with asbestos exposure and all 7 patients without a history of asbestos exposure. Three of 16 patients (19%) with benign asbestos-related pleural disease had a positive scan. 67Gallium radionuclide imaging is nonspecific but may be valuable in noninvasive monitoring of asbestos-exposed populations, which have a high risk for the late development of benign and/or malignant pleural disease
Differential Binding Models for Direct and Reverse Isothermal Titration Calorimetry.
Herrera, Isaac; Winnik, Mitchell A
2016-03-10
Isothermal titration calorimetry (ITC) is a technique to measure the stoichiometry and thermodynamics from binding experiments. Identifying an appropriate mathematical model to evaluate titration curves of receptors with multiple sites is challenging, particularly when the stoichiometry or binding mechanism is not available. In a recent theoretical study, we presented a differential binding model (DBM) to study calorimetry titrations independently of the interaction among the binding sites (Herrera, I.; Winnik, M. A. J. Phys. Chem. B 2013, 117, 8659-8672). Here, we build upon our DBM and show its practical application to evaluate calorimetry titrations of receptors with multiple sites independently of the titration direction. Specifically, we present a set of ordinary differential equations (ODEs) with the general form d[S]/dV that can be integrated numerically to calculate the equilibrium concentrations of free and bound species S at every injection step and, subsequently, to evaluate the volume-normalized heat signal (δQ(V) = δq/dV) of direct and reverse calorimetry titrations. Additionally, we identify factors that influence the shape of the titration curve and can be used to optimize the initial concentrations of titrant and analyte. We demonstrate the flexibility of our updated DBM by applying these differentials and a global regression analysis to direct and reverse calorimetric titrations of gadolinium ions with multidentate ligands of increasing denticity, namely, diglycolic acid (DGA), citric acid (CIT), and nitrilotriacetic acid (NTA), and use statistical tests to validate the stoichiometries for the metal-ligand pairs studied.
International Nuclear Information System (INIS)
Lazaro, Ana; Peñalosa, Conchita; Solé, Aran; Diarce, Gonzalo; Haussmann, Thomas; Fois, Magali; Zalba, Belén; Gshwander, Stefan; Cabeza, Luisa F.
2013-01-01
Highlights: ► Advances in intercomparative tests of enthalpy of phase change material (PCM). ► Enthalpy of PCM determined by DSC is influenced by certain factors. ► The influence factors were identified. ► A methodology to avoid these influences for heating measurements is proposed. ► Forthcoming steps are focused on calibration and cooling measurements. - Abstract: For the correct design of thermal storage systems using phase change materials (PCMs) in any application, as well as for their simulation, it is essential to characterise the materials from thermophysical and rheological standpoints (phase change enthalpy, thermal conductivity in solid and liquid phases, viscosity and density in function of temperature). Taking advantage of the different research groups facilities available in two international networks: within the IEA (International Energy Agency), the ECES Implementing Agreement (Energy Conservation through Energy Storage IA) and SHC Programme (Solar Heating and Cooling) Task 42/Annex 24 “Compact Thermal Energy Storage – Material Development for System Integration”, and the COST Action TU0802 “Next generation cost effective phase change materials for increased energy efficiency in renewable energy systems in buildings (NeCoE-PCM)” a set of Round Robin Tests (RRTs) was proposed. The objective was to come to comparable results for PCMs using Differential Scanning Calorimetry (DSC) to determine their melting enthalpy as well as their melting and solidification behaviour. The first RRT was without defining the procedure, the second one with a predefined procedure for the measurements, but not for calibration and the third one with a predefined procedure for calibration, for the measurements and also for the data evaluation. This paper presents the conclusions after the three RRT. The main conclusion of the paper is that enthalpy in function of temperature determined using a dynamic method for DSC can be influenced by certain reasons
Stemmer, A
1995-04-01
The design of a scanned-cantilever-type force microscope is presented which is fully integrated into an inverted high-resolution video-enhanced light microscope. This set-up allows us to acquire thin optical sections in differential interference contrast (DIC) or polarization while the force microscope is in place. Such a hybrid microscope provides a unique platform to study how cell surface properties determine, or are affected by, the three-dimensional dynamic organization inside the living cell. The hybrid microscope presented in this paper has proven reliable and versatile for biological applications. It is the only instrument that can image a specimen by force microscopy and high-power DIC without having either to translate the specimen or to remove the force microscope. Adaptation of the design features could greatly enhance the suitability of other force microscopes for biological work.
Thermal and mechanical properties of polypropylene/titanium dioxide nanocomposite fibers
International Nuclear Information System (INIS)
Esthappan, Saisy Kudilil; Kuttappan, Suma Kumbamala; Joseph, Rani
2012-01-01
Highlights: ► Wet synthesis method was used for the synthesis of TiO 2 nano particles. ► Mechanical properties of polypropylene fibers were increased by the addition of TiO 2 nanoparticles. ► Thermal stability of polypropylene fiber was improved significantly by the addition of TiO 2 nano particles. ► TiO 2 nanoparticles dispersed well in polypropylene fibers. -- Abstract: Titanium dioxide nanoparticles were prepared by wet synthesis method and characterized by transmission electron microscopy and X-ray diffraction studies. The nanotitanium dioxide then used to prepare polypropylene/titanium dioxide composites by melt mixing method. It was then made into fibers by melt spinning and subsequent drawing. Mechanical properties of the fibers were studied using Favimat tensile testing machine with a load cell of 1200 cN capacity. Thermal behavior of the fibers was studied using differential scanning calorimetry and thermogravimetric analysis. Scanning electron microscope studies were used to investigate the titanium dioxide surface morphology and crosssection of the fiber. Mechanical properties of the polypropylene fiber was improved by the addition of titanium dioxide nanoparticles. Incorporation of nanoparticles improves the thermal stability of polypropylene. Differential scanning calorimetric studies revealed an improvement in crystallinity was observed by the addition of titanium dioxide nanoparticles.
Jeppesen, S; Linderoth, S; Pryds, N; Kuhn, L Theil; Jensen, J Buch
2008-08-01
A simple and high-sensitivity differential scanning calorimeter (DSC) unit operating under magnetic field has been built for indirect determination of the magnetocaloric effect. The principle of the measuring unit in the calorimeter is based on Peltier elements as heat flow sensors. The high sensitivity of the apparatus combined with a suitable calibration procedure allows very fast and accurate heat capacity measurements under magnetic field to be made. The device was validated from heat capacity measurements for the typical DSC reference material gallium (Ga) and a La(0.67)Ca(0.33)MnO(3) manganite system and the results were highly consistent with previous reported data for these materials. The DSC has a working range from 200 to 340 K and has been tested in magnetic fields reaching 1.8 T. The signal-to-noise ratio is in the range of 10(2)-10(3) for the described experiments. Finally the results have been compared to results from a Quantum Design(R) physical properties measuring system. The configuration of the system also has the advantage of being able to operate with other types of magnets, e.g., permanent magnets or superconducting coils, as well as the ability to be expanded to a wider temperature range.
A new ultrasensitive scanning calorimeter.
Plotnikov, V V; Brandts, J M; Lin, L N; Brandts, J F
1997-08-01
A new ultrasensitive differential scanning calorimeter is described, having a number of novel features arising from integration between hardware and software. It is capable of high performance in either a scanning or isothermal mode of operation. Upscanning is carried out adiabatically while downscanning is nonadiabatic. By using software-controlled signals sent continuously to appropriate hardware devices, it is possible to improve adiabaticity and constancy of scan rate through use of empirical prerun information stored in memory rather than by using feedback systems which respond in real time and generate thermal noise. Also, instrument response time is software-selectable, maximizing performance for both slow- and fast-transient systems. While these and other sophisticated functionalities have been introduced into the instrument to improve performance and data analysis, they are virtually invisible and add no additional complexities into operation of the instrument. Noise and baseline repeatability are an order of magnitude better than published raw data from other instruments so that high-quality results can be obtained on protein solutions, for example, using as little as 50 microg of protein in the sample cell.
Electrical properties and conduction mechanism of [C2H5NH3]2CuCl4 compound
Mohamed, C. Ben; Karoui, K.; Jomni, F.; Guidara, K.; Rhaiem, A. Ben
2015-02-01
The [(C2H5)NH3]2CuCl4 compound was prepared and characterized by several technique: the X-ray powder diffraction confirms the purity of the synthetized compound, the differential scanning calorimetric show several phase transitions at 236 K, 330 K, 357 K and 371 K, the dialectical properties confirms the ferroelectric-paraelectric phase transition at 238 K, which is reported by V. Kapustianyk et al. (2007) [1]. The two semi-circles observed in the complex impedance identify the presence of the grain interior and grain boundary contributions to the electrical response in this material. The equivalent circuit is modeled by a combination series of two parallel RP-CPE circuits. The temperature dependence of the alternative current conductivity (σg) and direct current conductivity (σdc) confirm the observed transitions in the calorimetric study. The (AC) electrical conduction in [(C2H5)NH3]2CuCl4 was studied by two processes that can be attributed to a hopping transport mechanism: the non-overlapping small polaron tunneling (NSPT) model in phase III and the correlated barrier hopping (CBH) model in phases I, II, IV, V and VI.
Studies of atomic collisions in solids by means of calorimetric techniques
International Nuclear Information System (INIS)
Andersen, H.H.
1974-10-01
The results of the application of the calorimetric technique to measure the way in which the energy of particles passed through a thin foil and stopped within a solid block is disturbed between the foil and the block are presented. This measurement gives the relative energy loss of the projectile in the foil and hence, since the foil thickness is measured independently, the stopping power. Radiation-damage measurements are discussed. In these measurements, the same cryostat as that employed in the stopping-power measurements was used. The foil was left out and the block remained as a very efficient dosimetry device. Furthermore, a number of experimental complications must be taken into account when damage is measured. Finally, results are presented of the measurement of energy distribution between two systems, this time performed at room temperature. The measurements are not nearly as accurate as those performed at low temperatures, but the physical property studied, the energy reflected from a solid surface bombarded with low-energy heavy ions (sputtering efficiency) could hardly be studied in any other way. The thesis is a summary of thirteen publications on energetic-particle calorimetry, all these papers being reproduced as appendices to the main text. (B.R.H.)
Differences in MRI findings in cases showing ring-enhancement on a CT scan
International Nuclear Information System (INIS)
Tokiwa, Kaichi; Hashimoto, Takashi; Miyasaka, Yoshio; Yada, Kenzoh; Kan, Shinichi; Takagi, Hiroshi.
1990-01-01
It is sometimes difficult to differentiate between a brain abscess and a tumor, for both show ring-enhancement on a CT scan. The present authors have studied the benefit of MRI for the differential diagnosis of these two lesions. The subjects of this study were 6 cases of brain abscess and 10 cases of brain tumor, all of them showing ring-enhancement on a CT scan. The MRI findings were compared with those of the CT scan taken at almost the same time, especially focussing on the difference in the ring-enhancement. In 5 out of the 6 cases of brain abscess, T 2 -weighted MRI demonstrated a comparatively thin and homogeneous low-intensity, round rim. In the cases of brain tumor, however, none of the cases demonstrated this typical low-intensity, round rim; rather, in them the rim was thick and irregular. The authors can conclude that those MRI findings can serve as important differential diagnostic findings between brain abscess and tumor; also, MRI may be used as a landmark for terminating the administration of antibiotics in cases of brain abscess. (author)
Calorimetric Low-Temperature Detectors for X-Ray Spectroscopy on Trapped Highly-Charged Heavy Ions
Kilbourne, Caroline; Kraft-Bermuth, S.; Andrianov, V.; Bleile, A.; Echler, A.; Egelhof, P.; Ilieva, S.; Kilbourne, C.; McCammon, D.
2012-01-01
The application of Calorimetric Low-Temperature Detectors (CLTDs) has been proposed at the Heavy-Ion TRAP facility HITRAP which is currently being installed at the Helmholtz Research Center for Heavy Ion Research GSI. This cold ion trap setup will allow the investigation of X-rays from ions practically at rest, for which the excellent energy resolution of CLTDs can be used to its full advantage. However, the relatively low intensities at HITRAP demand larger solid angles and an optimized cryogenic setup. The influence of external magnetic fields has to be taken into account. CLTDs will also be a substantial part of the instrumental equipment at the future Facility for Antiproton and Heavy Ion Research (FAIR), for which a wide variety of high-precision X-ray spectroscopy experiments has been proposed. This contribution will give an overview on the chances and challenges for the application of CLTDs at HITRAP as well as perspectives for future experiments at the FAIR facility.
Selenomethionine Se 75 thymus scans in myasthenia gravis
Energy Technology Data Exchange (ETDEWEB)
Toole, J.F.; Cowan, R.; Maynard, D.; Witcofski, R.L.; Janeway, R.
1975-01-01
In 1966, Toole and Witcofski introduced selenomethionine Se 75 mediastinal scanning as a diagnostic test for thymomas. Since then we have performed such scans on patients with myasthenic syndrome. Because the technique is atraumatic, safe, and accurate, it can be performed on critically ill myasthenics. Two hundred and fifty microcuries of selenomethionine Se 75 is injected intravenously. Within 1 hour the mediastinum from the suprasternal notch to the ziphoid process is scanned, using a 2 x 3 inch scanner. Delayed scans have been made in a few instances but they have not increased the number of positive cases. Selenomethionine Se 75 is incorporated into tissues undergoing rapid protein synthesis such as thyroid, pancreas, liver, and lymphomas. Of the 34 mediastinal scans performed on myasthenics between 1966 and December 31, 1974, 4 were positive for thymoma. In addition, there was a positive scan with uptake in an area of atelectasis of the lung adjacent to the mediastinum. Of interest is the fact that 1 patient with carcinoma of the lung had a positive scan over the lesion. In 13 patients with chronic lymphatic leukemia the mediastinal scans were negative. In another patient with a mediastinal mass noted on chest x-ray, a variety of differential diagnostic possibilities were considered, such as pericardial cyst, dermoid, and aneurysm. A selenomethionine scan was strongly positive, suggesting a thymoma which subsequent surgery confirmed.
Clinical significant of three phase radionuclide bone scan
Energy Technology Data Exchange (ETDEWEB)
Kim, Sun Hee; Suh, Jin Suck; Park, Chang Yun [Yonsei University College of Medicine, Seoul (Korea, Republic of)
1989-04-15
Three phase radionuclide bone scan, consisting of a radionuclide angiogram, an immediate postinjection blood pool image, and 4hr delayed images, was randomly performed in 182 patients, who had been suffered from either local pain or tenderness. Authors analysed 3 phase bone scan in 74 patients with correct diagnosis proven surgically or clinically, from July 1987 to August, 1988. The results were as follows: 1. Overall sensitivity of 3 phase bone scan was 85.4%: sensitivity in patients with an osseous lesion was 90.4% as opposed to 72.7% in patients with a nonosseous lesion. 2. There was no difference in the detection rate of the osseous lesions between the 3 phase bone scan and the delayed image bone scan. However, because the detection rate was higher on the 3 phase bone scan than it was on only the delayed image bone scan (55%) in instance of the nonosseous lesion, we would suggest that 3 phase bone scan might be obtained in cases suspected of the nonosseous lesions. 3. When the presumptive diagnosis was a bone tumor, sensitivity and specificity for malignancy were 67%, 100% respectively. 4. In differentiating osteomyelitis from cellulitis, sensitivity was 94%, specificity was 100%. 5. 3 phase bone scan was able to provide the precise information about either vasculaturity or localization of lesion in some cases of soft tissue mass and avascular necrosis of hips.
Zhang, Hui; Taxipalati, Maierhaba; Que, Fei; Feng, Fengqin
2013-12-01
The microstructure transitions of a food-grade U-type microemulsion system containing glycerol monolaurate and propionic acid at a 1:1 mass ratio as oil phase and Tween 80 as surfactant were investigated along a water dilution line at a ratio of 80:20 mass% surfactant/oil phase, based on a previously studied phase diagram. From the water thermal behaviours detected by differential scanning calorimetry, three structural regions are identified along the dilution line. In the first region, all water molecules are confined to the water core of the reverse micelles, leading to the formation of w/o microemulsion. As the water content increases, the water gains mobility, transforms into bicontinuous in the second region, and finally the microemulsion become o/w in the third region. The thermal transition points coincide with the structural phase transitions by electrical conductivity measurements, indicating that the structural transitions occur at 35 and 65 mass% of water along the dilution line. Copyright © 2013 Elsevier Ltd. All rights reserved.
Differential diagnosis of metastases in bone scans: chemotherapy induced bone necrosis
International Nuclear Information System (INIS)
Reuland, P.
1999-01-01
Aim: Influenced by the incorrect diagnosis of a bone metastasis caused by bone necrosis we evaluated reasons and frequency of bone necrosis in patients referred for bone scanning in follow-up of tumors. Methods: Bone scans performed within two years on patients with primary bone tumors or tumors metastatic to bone were reviewed in respect to the final diagnosis bone necrosis. Results: We found the cases of three young patients who presented the appearance of hot spots on bone scintigrams which were finally diagnosed as bone necrosis. In two cases the diagnosis was based on histological findings, in one case the diagnosis was made evident by follow-up. All the three patients had been treated by chemotherapy and presented no other reason for the development of bone necrosis. Enhanced tracer uptake in all sites decreased within eight weeks up to two years without therapy. Conclusion: Single and multiple hot spots after chemotherapy may be originated by bone necrosis but mimikry metastases. (orig.) [de
Synthesis, crystal structures and properties of new quinolinium derivatives
Zhang, Xinyuan; Jiang, Xingxing; Li, Yin; Lin, Zheshuai; Zhang, Guochun; Wu, Yicheng
2015-11-01
Four phenyl-substituted quinolinium salts with different counter anions, C27H27NO4S, C26H25NO5S, C25H22NO5SCl, and C25H22NO5SBr, were synthesized and their single crystals were successfully grown from methanol solution by slow evaporation. Single crystal X-ray diffraction analyses showed that C27H27NO4S crystal belongs to the noncentrosymmetric orthorhombic space group Pna21, and the other three crystals belong to centrosymmetric monoclinic space group P21/n. Their first order hyperpolarization and macroscopic nonlinearity were analyzed and physical properties were characterized by UV-vis absorption spectroscopy, and differential scanning calorimetric and thermal gravimetric analysis.
Combustion of Sewage Sludge as Alternative Fuel for Cement Industry
Institute of Scientific and Technical Information of China (English)
LI Fuzhou; ZHANG Wei
2011-01-01
The combustion of sewage sludge and coal was studied by thermogravimetric analysis.Both differential scanning calorimetric analysis and derivative thermogravimetric profiles showed differences between combustion of sewage sludge and coal, and non-isothermal kinetics analysis method was applied to evaluate the combustion process. Based on Coats-Redfem integral method, some reaction models were tested,the mechanism and kinetics of the combustion reaction were discussed. The results show that the combustion of sewage sludge is mainly in the Iow temperature stage, meanwhile the ignition temperature and Arrhenius activation energy are lower than that of coal. The combustion of sewage sludge has the advantage over coal in some aspects, thus sewage sludge can partly replace coal used as cement industry fuel.
Reactivity of Monolayer Protected Silver Clusters Towards Excess Ligand: A Calorimetric Study
Baksi, Ananya
2017-10-31
Reactivity of monolayer protected atomically precise clusters of noble metals is of significant research interest. Till date very few experimental data are available on the reaction thermodynamics of such clusters. Here we report a calorimetric study of the reaction of glutathione (GSH) protected silver clusters in presence of excess ligand, GSH using isothermal titration calorimetry (ITC). We have studied Ag11(SG)7 and Ag32(SG)19 clusters and compared their reactivity with GSH protected silver nanoparticles (AgNPs) and silver ions. Clusters show intermediate reactivity towards excess ligand com-pared to nanoparticles and silver ions. Several control experiments were performed to understand the degradation mech-anism of these silver clusters and nanoparticles. Effect of dissolved oxygen in the degradation process was studied in de-tail and found that it did not have a significant role, although alternate pathways of degradation with the involvement of oxygen cannot be ruled out. Direct confirmation of the fact that functionalized metal clusters fall in-between NPs and atomic systems in their stability is obtained experimentally for the first time. Several other thermophysical parameters of these clusters were also determined including, density, speed of sound, isentropic compressibility and coefficient of thermal expansion.
Experiencias de calorimetría diferencial de barrido en aleaciones Al-Si
Directory of Open Access Journals (Sweden)
Carolina López-Eckerdt
2016-01-01
Full Text Available La observación de agujas características de una transformación displaciva en aleaciones U-Al-Si en el entorno del compuesto U3Si5 evidencia la necesidad de analizar las distintas transformaciones que ocurren durante el enfriamiento utilizando una técnica dinámica de identificación de transformaciones (calorimetría diferencial de barrido. Para evaluar la versatilidad de esta técnica, se estudiaron aleaciones Al-Si con concentraciones de Si entre 0,6% y 7,1% en peso. Se determinaron las temperaturas liquidus y eutéctica de cada aleación y se estimó la entalpía de formación de los precipitados de Si y de la reacción eutéctica. Los resultados reproducen las temperaturas de ambas reacciones según el diagrama de equilibrio del sistema binario Al-Si. Para el cálculo de las entalpías de transformación resulta indispensable obtener el porcentaje de fase transformada por otras técnicas de caracterización una vez finalizado el ensayo.
International Nuclear Information System (INIS)
Xiao Zhongliang; Chen Qiyuan; Yin Zhoulan; Hu Huiping; Wu Daoxin
2005-01-01
The structural changes of mechanically activated sphalerite and pyrite under different grinding conditions were determined by X-ray powder diffraction (XRD), laser particle size analyzer and elemental analysis. The storage energy of mechanically activated sphalerite and pyrite was measured by a calorimetric method. A thermochemical cycle was designed so that mechanically activated and non-activated minerals reached the same final state when dissolved in the same oxidizing solvent. The results show that the storage energy of mechanically activated sphalerite and pyrite rises with increased in grinding time, and reaches a maximum after a certain grinding period. The storage energy of mechanically activated pyrite decreases when heated under inert atmosphere. The storage energy of mechanically activated sphalerite and pyrite remains constant when treated below 573 K under inert atmosphere. The percentage of the storage energy caused by surface area increase during mechanical activation decreases with increasing grinding time. These results support our opinion that the mechanically activated storage energy of sphalerite is closely related to lattice distortions, and the mechanically activated storage energy of pyrite is mainly caused by the formation of reactive sites on the surface
Hepatobiliary scan in neonatal Jaundice
International Nuclear Information System (INIS)
Nahar, Nurun; Hasan, Mizanul; Karim, M.A.
2002-01-01
Jaundice is more or less common in newborn babies. Through physiological jaundice is most common cause of neonatal jaundice, possibility of obstructive jaundice especially biliary atresia should be kept in mind. Early diagnosis of biliary atresia followed by surgical treatment can save baby's life. Otherwise death is inevitable due to liver failure. Hepatobiliary scan is the imaging study of choice in neonatal jaundice especially when there is persistent conjugated hyperbilirubinaemia. Total 27 newborn babies of suspected biliary atresia, aged 14 days to 4 months were referred to Institute of Nuclear Medicine for Hepatobiliary scan. All of them had high serum bilirubin ranged from 6.0 mg/dl with an average of 9.35 ng/dl serum bilirubin level. Ultrasonography of hepatobiliary system was performed in 14 cases showing normal sized liver in 4 cases and hepatomegaly in 10 cases. Hepatobiliary scan was done with 99m Tc-Mebrofenin (Br IDA) after preparing the baby with phenobarbitone for 3-5 days. 20 (67%) cases were scan positive suggesting biliary atresia (BA) and 7(27%) cases were scan negative. In BA there will be increased hepatic uptake of the radionuclide without any significant excretion even in 24 hours delayed images. Presence of radiotracer in the bowel exclude the diagnosis of BA. Early diagnosis of biliary atresia is very important because in this condition surgery should be performed early (within 60 days of life). Studies suggest that hepatobiliary scan after hepatic stimulation with phenobarbitone for a period of 3-5 days is highly accurate for differentiating biliary atresia from other causes of neonatal jaundice. It is very important to perform hepatobiliary scan in a case of neonatal jaundice to exclude biliary atresia for the sake of baby's life.(author)
Energy Technology Data Exchange (ETDEWEB)
Meier, J; Boehmer, W; Egelhof, P; Henning, W; Kienlin, A v [Gesellschaft fuer Schwerionenforschung mbH, Darmstadt (Germany) Mainz Univ. (Germany). Inst. fuer Physik; Shepard, K W [Argonne National Lab., IL (United States)
1991-10-01
A low temperature bolometer for the calorimetric detection of heavy ions was constructed and tested. An aluminium thin-film microstrip, patterned in a meander-line structure by photolithographic techniques, serves as superconducting transition edge thermometer on a sapphire absorber. A transition width {delta}T of the thermometer of the order of some mK, and a resistance of up to R{sub c} = 60 k{Omega} at the working point (T{sub c} {approx equal} 1.5 K) is achieved. In tests with {alpha}-particles signals of typically 1 V pulseheight after the preamplifier and decaytimes around hundred {mu}s were observed. For 5.5 MeV {alpha}-particles the measured energy resolution is {Delta}E = 50 keV, corresponding to a temperature resolution of about 1 {mu}K. First measurements were performed with {sup 20}Ne ions (E = 116 MeV). The dependence of the pulseheight and the FWHM on the working point were investigated and qualitatively explained. The best energy resolution was {Delta}E = 2.6 MeV; most probably the present limitations are determined by the temperature stabilization. (orig.).
Differential thermal analysis microsystem for explosive detection
DEFF Research Database (Denmark)
Olsen, Jesper Kenneth; Greve, Anders; Senesac, L.
2011-01-01
as a small silicon nitride membrane incorporating heater elements and a temperature measurement resistor. In this manuscript the DTA system is described and tested by measuring calorimetric response of 3 different kinds of explosives (TNT, RDX and PETN). This project is carried out under the framework...
Directory of Open Access Journals (Sweden)
Nassu, Renata Tieko
1999-02-01
Full Text Available Melting point of fats is used to characterize oils and fats and is related to their physical properties, such as hardness and thermal behaviour. The present work shows the utilization of DSC technique on the determination of melting point of fats. In a comparison with softening point (AOCS method Cc 3-25, DSC values were higher than those obtained by AOCS method. It has occurred due to the fact that values obtained by DSC technique were taken when the fat had melted completely. DSC was also useful for determining melting point of liquid oils, such as soybean and cottonseed ones.
El punto de fusión de grasas es usado para caracterizar aceites y grasas, y está relacionado con sus propiedades físicas, tales como dureza y comportamiento térmico. El presente trabajo muestra la utilización de la técnica de Calorimetría Diferencial de Barrido (DSC en la determinación del punto de fusión de grasas. En comparación con el punto de ablandamiento (AOCS método Cc 3-25, los valores de DSC fueron más altos que los obtenidos por los métodos de AOCS. Esto ha ocurrido debido al hecho que los valores obtenidos por la técnica de DSC fueron tomados cuando la grasa había fundido completamente. DSC fue también útil para determinar puntos de fusión de aceites líquidos, tales como los de soya y algodón.
Directory of Open Access Journals (Sweden)
Eva GarcÃa-Millán
2017-12-01
Full Text Available The data presented in this article describe the physical state of the triamcinolone acetonide (TA in nanosuspension stabilized with polyvinyl alcohol (PVA and poloxamer 407 (PL. The data were assessed by X-ray spectroscopy, ATR Fourier transforms infrared spectroscopy measurements (FTIR, and Differential scanning calorimetry (DSC analysis. PVA, PL and polymeric mixture (PVA and PL were compared with nanosuspension and the interactions between drug triamcinolone acetonide and polymers were studied. The data are related and are complementary to the research article entitle âImproved release of triamcinolone acetonide from medicated soft contact lenses loaded with drug nanosuspensionsâ (GarcÃa-Millán et al., 2017 [1]. Keywords: Triamcinolona acetonide nanosuspensiones, X-ray spectroscopy, FTIR spectroscopy, DSC
Clinical Utility of bone Scan in the Diagnosis of Temporomandibular disorders
International Nuclear Information System (INIS)
Kim, In Joo; Kang, Yang Ho; Son, Seok Man; Lee, Kyoung Seog; Lee, Jae Bok; Kim, Yong Ki; Seo, Bong Jik; Park, June Sang; Park, June Sang; Ko, Myung Yun; Son, Seong Pyo
1995-01-01
Bone scan is a very sensitive diagnostic imaging test for detecting bone and joint disorders. So it might be useful in the diagnosis of temporomandibular disorders of the joint origin. Thus, the effectiveness of bone scan for detecting temporomandibular joint(TMJ) diseases and differentiating the TMJ disc displacement from the TMJ arthritis was evaluated. Bone scan was done in 21 patients with TMJ disc displacement (I3 unilaterally affected, 8 bilaterally affected), 26 patients with TMJ arthritis (23 unilateral, 3 bilateral), and 39 volunteers with no signs, symptoms, or history of TMJ disease TMJ simple uptake rate(SUR) and difference of both TMJ SUR were calculated from the 100,000 count lateral image of head and neck region in 99m Tc MDP bone scan. Transcranial and panorama X-ray examination was also done in all patients. TMJ SUR(%) were 1.67 ±0.606 in TMJs affected with arthritis, 1.350±0.351 in TMJs affected with disc displacement, and 1.084±0.172 in TMJs of controls Significant differences were demonstrated among them(p mean+2SD of controls) in unilateral TMJ arthritis patients were significantly higher than those in patients with unilateral TMJ disc displacement(69.6% and 87% vs 23.1% and 23%). Conclusively, bone scan may help to detect TMJ disease and differentiate TMJ disc displacement from TMJ arthritis.
Energy Technology Data Exchange (ETDEWEB)
Niden, A.H.; Mishkin, F.S.; Khurana, M.M.L.; Pick, R.
1977-03-21
Twenty-three patients with clinical signs of pulmonary embolic disease and lung infiltrates were studied to determine the value of gallium citrate /sup 67/Ga lung scan in differentiating embolic from inflammatory lung disease. In 11 patients without angiographically proved embolism, only seven had corresponding ventilation-perfusion defects compatible with inflammatory disease. In seven of these 11 patients, the /sup 67/Ga concentration indicated inflammatory disease. In the 12 patients with angiographically proved embolic disease, six had corresponding ventilation-perfusion defects compatible with inflammatory disease. None had an accumulation of /sup 67/Ga in the area of pulmonary infiltrate. Thus, ventilation-perfusion lung scans are of limited value when lung infiltrates are present. In contrast, the accumulation of /sup 67/Ga in the lung indicates an inflammatory process. Gallium imaging can help select those patients with lung infiltrates who need angiography.
Energy Technology Data Exchange (ETDEWEB)
Johari, G.P., E-mail: joharig@mcmaster.ca
2014-04-01
Highlights: • Stress release in a glass occurs at a faster rate than structural relaxation. • Plastically-deformed glass would show two exothermic minima, and no glass transition. • Enthalpy matching procedure would yield an inaccurate fictive temperature. • Complex heat capacity may distinguish plastically-deformed from quench-formed glass. - Abstract: Plastic deformation of crystals and glasses produces internal strains (stresses), which change their energy and other thermodynamic properties. On annealing, these stresses decrease at a rate faster than the structure relaxes toward the equilibrium state. Mechanism of such relaxations in crystals differs from that in glasses and it also differs for glasses of different types. In all cases, the energy related properties decrease with time isothermally and on heating, resembling the structure relaxation of a stress-free glass. We consider these features and argue that kinetics of enthalpy loss with time yields the rate constants of the stress release and of the structure change, and not the viscosity determining α-relaxation time. Since thermal cycling does not recover the enthalpy from internal stresses, a glass with stresses has neither a glass-softening temperature, T{sub g}, nor a fictive temperature, T{sub f}. Plastic deformation would not rejuvenate a physically aged glass to the properties of its un-aged state. The Prigogine–Defay ratio can be extended to all T{sub f}s, and used to investigate the effect of distribution of relaxation times on its value, but it can not be defined for an internally stressed glass. After discussing the effects of annealing on the heat capacity and DSC scans, we conclude that on slow heating, glass with deformation-induced stresses would show two exothermic minima, and normal glass would show only one such minimum. Temperature-modulated scanning calorimetry would also distinguish an internally stressed glass from an equally high-enthalpy, stress-free glass. Enthalpy
Classification of lymph nodes in computerized tomography scans using extracting tools
International Nuclear Information System (INIS)
Alves, Allan F.F.; Pina, Diana R. de; Altemani, Joao M.C.
2016-01-01
Lymph node changes in the neck region may be originated by both inflammatory and tumor causes. Diagnostic imaging method such as computed tomography are used to distinguish between these two main causes of lymph nodes alterations. In this work we used feature extracting tools I CT scans such as the average value of pixels, wavelet entropy, skewness and kurtosis to assist the radiologist in diagnosing lymph nodes alterations. The wavelet entropy proved to be the best image characteristic parameter to differentiate between the two groups of patients evaluated in this study. The study of cervical lymph nodes changes by features extraction methods may prove to be an excellent tool to assist in differentiating between infectious / inflammatory and tumor causes in CT scans. (author)
Usefulness of 99mTc-Sestamibi whole body scan in the follow-up of differentiated thyroid cancer
International Nuclear Information System (INIS)
Pastore, Francisco A.; Fernandez, C.; Rios, V.; Funes Lorea, A; Volpe, B.; Lopez, S.
2006-01-01
Although radioiodine is and had been the more common used radioisotope in the follow-up of differentiated thyroid cancer (DTC), other radioisotopes, such as 99m Tc sestamibi (MIBI), had been incorporated as auxiliary methods. Our objective was to assess the diagnostic usefulness of MIBI in the long term follow-up of DTC. Thirty-two patients (26 (81%) female), mean age 45 ± 12.6 years, 2 with follicular carcinoma, and 30 with papillary carcinoma, were prospectively studied with MIBI. Mean time of follow-up from thyroidectomy to MIBI was 4.6 ± 4.9 years. (range, 7 months to 22 years). Sensitivity (Sens), specificity (Spec), positive predictive value (PPV), negative predictive value (NPV), and accuracy (A) was evaluated. We assessed agreement for MIBI and 131 I, by means of percent agreement and Cohen's kappa (k) statistic. The gold standard method to indicate persistent disease was serum thyroglobulin (Tg) measurement by ICMA, with cut-off level of = 2 ng/ml 'off T4', and > 0.2 ng/ml 'on T4'. In 3 patients with positive anti-Tg antibodies, 131 I scan and other auxiliary methods (Ultrasound, CT scan) were considered as gold standard. For MIBI the values of Sens, Spec, PPV, NPP, and A were 29% (26-32), 93% (89-96), 83% (74-91), 53% (51-55), and 59% (57-61), respectively. For 131 I were 31% (27-34), 100% (96-100), 100% (90-100), 56% (53-58), and 63% (61-65), respectively. The percent agreement between both radiopharmaceuticals was 76.6%, and k was 0.2 (-0.19 -0.63). Similar statistical indicators for MIBI and 131 I warrant the use of the former as alternative method. At the same time, a fair agreement between both radiopharmaceuticals demonstrates the additive information offered by MIBI in the follow-up of DTC. (author) [es
Meng, Frank H; Schricker, Scott R; Brantley, William A; Mendel, Deborah A; Rashid, Robert G; Fields, Henry W; Vig, Katherine W L; Alapati, Satish B
2007-12-01
Employ differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) to investigate thermal transformations in three mouthguard materials and provide insight into their previously investigated energy absorption. Samples (13-21mg) were obtained from (a) conventional ethylene vinyl acetate (EVA), (b) Pro-form, another EVA polymer, and (c) PolyShok, an EVA polymer containing polyurethane. Conventional DSC (n=5) was first performed from -80 to 150 degrees C at a heating rate of 10 degrees C/min to determine the temperature range for structural transformations. Subsequently, TMDSC (n=5) was performed from -20 to 150 degrees C at a heating rate of 1 degrees C/min. Onset and peak temperatures were compared using ANOVA and the Tukey-Kramer HSD test. Other samples were coated with a gold-palladium film and examined with an SEM. DSC and TMDSC curves were similar for both conventional EVA and Pro-form, showing two endothermic peaks suggestive of melting processes, with crystallization after the higher-temperature peak. Evidence for crystallization and the second endothermic peak were much less prominent for PolyShok, which had no peaks associated with the polyurethane constituent. The onset of the lower-temperature endothermic transformation is near body temperature. No glass transitions were observed in the materials. SEM examination revealed different surface morphology and possible cushioning effect for PolyShok, compared to Pro-form and EVA. The difference in thermal behavior for PolyShok is tentatively attributed to disruption of EVA crystal formation, which may contribute to its superior impact resistance. The lower-temperature endothermic peak suggests that impact testing of these materials should be performed at 37 degrees C.
Differential diagnosis of tuberculous pleural effusion and malignant
International Nuclear Information System (INIS)
Na, Eui Sung; Kim, Young Nam; Lee, Mee Ran; Oh, Yu Whan; Kang, Eun Young
1997-01-01
The purpose of this study is to evaluate the diagnostic accuracy of CT in the differential diagnosis of tuberculous and malignant pleural effusion whether or not lung lesions are present, and to investigate the CT findings used for this differential diagnosis. This study involved 30 patients with tuberculous pleural effusion (mean age, 44.6 years; M : F = 19:11) and 20 with malignant pleural effusion (mean age, 57.2 years; M: F=10:10). All 50 patients underwent enhanced CT chest scans, and the respective conditions were pathologically confirmed. Two radiologists unaware of the pathologic results and distributions of patients reviewed these scans, CT findings of pleural effusions, their diagnoses, and the degree of confidence of their diagnoses. In most cases, CT provided correct differential diagnosis between tuberculous and malignant pleural effusion. It can help determine the nature of associated lung and pleural lesions, and specific findings of the latter, and can accurately differentiate tuberculous and malignant pleural effusion. (author). 20 refs., 3 tabs., 5 figs
Directory of Open Access Journals (Sweden)
Alexander M. Brannan
2015-12-01
Full Text Available Differential Scanning Calorimetry (DSC of intact Escherichia coli (E. coli was used to identify non-lipidic targets of the antimicrobial peptide (AMP MSI-78. The DSC thermograms revealed that, in addition to its known lytic properties, MSI-78 also has a striking effect on ribosomes. MSI-78’s effect on DSC scans of bacteria was similar to that of kanamycin, an antibiotic drug known to target the 30S small ribosomal subunit. An in vitro transcription/translation assay helped confirm MSI-78’s targeting of ribosomes. The scrambled version of MSI-78 also affected the ribosome peak of the DSC scans, but required greater amounts of peptide to cause a similar effect to the unscrambled peptide. Furthermore, the effect of the scrambled peptide was not specific to the ribosomes; other regions of the DSC thermogram were also affected. These results suggest that MSI-78’s effects on E. coli are at least somewhat dependent on its particular structural features, rather than a sole function of its overall charge and hydrophobicity. When considered along with earlier work detailing MSI-78’s membrane lytic properties, it appears that MSI-78 operates via a multi-hit mechanism with multiple targets.
Bartlett, Philip N; Guerin, Samuel
2003-01-01
Palladium films with regular nanoarchitectures were electrochemically deposited from the hexagonal (H1) lyotropic liquid crystalline phase of the nonionic surfactant octaethyleneglycol monohexadecyl ether (C16EO8) onto micromachined silicon hotplate structures. The H1-e Pd films were shown to have high surface areas (approximately 28 m2 g(-1)) and to act as effective and stable catalysts for the detection of methane in air on heating to 500 degrees C. The response of the H1-e Pd-coated planar pellistors was found to be linearly proportional to the concentration of methane between 0 and 2.5% in air with a detection limit below 0.125%. Our results show that the electrochemical deposition of nanostructured metal films offers a promising approach to the fabrication of micromachined calorimetric gas sensors for combustible gases.
Energy Technology Data Exchange (ETDEWEB)
Brun, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1964-07-01
After having reviewed the various interaction processes occurring between radiations present in nuclear reactors and matter, the author describes the different calorimetric methods which may be used for measuring the energy absorbed in the materials. He then gives a detailed description of the adiabatic calorimeter, the associated measurement device and the calibration methods which have been chosen. He finally gives values for the heating produced at various experimental positions in the reactors EL-2 and EL-3 for several materials currently used in reactor construction. (author) [French] Apres avoir passe en revue les differents processus d'interaction des rayonnements, existant dans les reacteurs nucleaires, avec la matiere, l'auteur decrit les differentes methodes calorimetriques qui peuvent etre utilisees pour mesurer l'energie absorbee dans les materiaux. II presente ensuite en detail le calorimetre adiabatique, le dispositif de mesure associe et les methodes d'etalonnage qui ont ete retenus. Enfin il donne des valeurs d'echauffement dans divers emplacements experimentaux des piles EL-2 et EL-3 pour differents materiaux d'utilisation courante dans les reacteurs. (auteur)
Algorithm-enabled partial-angular-scan configurations for dual-energy CT.
Chen, Buxin; Zhang, Zheng; Xia, Dan; Sidky, Emil Y; Pan, Xiaochuan
2018-05-01
We seek to investigate an optimization-based one-step method for image reconstruction that explicitly compensates for nonlinear spectral response (i.e., the beam-hardening effect) in dual-energy CT, to investigate the feasibility of the one-step method for enabling two dual-energy partial-angular-scan configurations, referred to as the short- and half-scan configurations, on standard CT scanners without involving additional hardware, and to investigate the potential of the short- and half-scan configurations in reducing imaging dose and scan time in a single-kVp-switch full-scan configuration in which two full rotations are made for collection of dual-energy data. We use the one-step method to reconstruct images directly from dual-energy data through solving a nonconvex optimization program that specifies the images to be reconstructed in dual-energy CT. Dual-energy full-scan data are generated from numerical phantoms and collected from physical phantoms with the standard single-kVp-switch full-scan configuration, whereas dual-energy short- and half-scan data are extracted from the corresponding full-scan data. Besides visual inspection and profile-plot comparison, the reconstructed images are analyzed also in quantitative studies based upon tasks of linear-attenuation-coefficient and material-concentration estimation and of material differentiation. Following the performance of a computer-simulation study to verify that the one-step method can reconstruct numerically accurately basis and monochromatic images of numerical phantoms, we reconstruct basis and monochromatic images by using the one-step method from real data of physical phantoms collected with the full-, short-, and half-scan configurations. Subjective inspection based upon visualization and profile-plot comparison reveals that monochromatic images, which are used often in practical applications, reconstructed from the full-, short-, and half-scan data are largely visually comparable except for some
Hwang, Deng-Fwu; Hsieh, Tzu-Feng; Lin, Shan-Yang
2013-01-01
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.
Núñez-Santiago, María C.; Maristany-Cáceres, Amira J.; Suárez, Francisco J. García; Bello-Pérez, Arturo
2008-07-01
Rheological behavior at 60 °C, granule size distribution and Differential Scanning Calorimetry (DSC) tests were employed to study the effect of diverse reaction conditions: adipic acid concentration, pH and temperature during cross-linking of banana (Musa paradisiaca) starch. These properties were determined in native banana starch pastes for the purpose of comparison. Rheological behavior from pastes of cross-linked starch at 60 °C did not show hysteresis, probably due the cross-linkage of starch that avoided disruption of granules, elsewhere, native starch showed hysteresis in a thixotropic loop. All pastes exhibited non-Newtonian shear thinning behavior. In all cases, size distribution showed a decrease in the median diameter in cross-linked starches. This condition produces a decrease in swelling capacity of cross-linked starch. The median diameter decreased with an increase of acid adipic concentration; however, an increase of pH and Temperature produced an increase in this variable. Finally, an increase in gelatinization temperature and entalphy (ΔH) were observed as an effect of cross-linkage. An increase in acid adipic concentration produced an increase in Tonset and a decrease in ΔH. pH and temperature. The cross-linked of banana starch produced granules more resistant during the pasting procedure.
Mura, P; Furlanetto, S; Cirri, M; Maestrelli, F; Marras, A M; Pinzauti, S
2005-02-07
A systematic analysis of the influence of different proportions of excipients on the stability of a solid dosage form was carried out. In particular, a d-optimal mixture experimental design was applied for the evaluation of glibenclamide compatibility in tablet formulations, consisting of four classic excipients (natrosol as binding agent, stearic acid as lubricant, sorbitol as diluent and cross-linked polyvinylpyrrolidone as disintegrant). The goal was to find the mixture component proportions which correspond to the optimal drug melting parameters, i.e. its maximum stability, using differential scanning calorimetry (DSC) to quickly obtain information about possible interactions among the formulation components. The absolute value of the difference between the melting peak temperature of pure drug endotherm and that in each analysed mixture and the absolute value of the difference between the enthalpy of the pure glibenclamide melting peak and that of its melting peak in the different analyzed mixtures, were chosen as indexes of the drug-excipient interaction degree.
Energy Technology Data Exchange (ETDEWEB)
Mason, P.C.; Gaulin, B.D. [Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, L8S 4M1 (CANADA); Epand, R.M. [Department of Biochemistry, McMaster University, Hamilton, Ontario, L8N 3Z5 (CANADA); Wignall, G.D.; Lin, J.S. [Center for Small-Angle Scattering Research, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States)
1999-03-01
High-resolution differential scanning calorimetry (DSC) and small angle neutron scattering (SANS) experiments have been conducted on large unilamellar vesicles (LUV{close_quote}s) of the phospholipid dipalmitoylphosphatidylcholine (DPPC) in excess water. The DSC results indicate a phase transition at temperatures corresponding to the gel (L{sub {beta}{sup {prime}}}) to ripple (P{sub {beta}{sup {prime}}}) phase transition seen in multilamellar vesicles of DPPC while the SANS experiments provide direct evidence for the formation of the P{sub {beta}{sup {prime}}} phase in these systems. In addition, it is shown that SANS is an effective technique for extracting structural parameters such as vesicle radius and thickness in LUV model membrane systems. {copyright} {ital 1999} {ital The American Physical Society}
Magnetic and calorimetric investigations of ferromagnetic shape memory alloy Ni54Fe19Ga27
International Nuclear Information System (INIS)
Sharma, V K; Chattopadhyay, M K; Kumar, Ravi; Ganguli, Tapas; Kaul, Rakesh; Majumdar, S; Roy, S B
2007-01-01
We report results of magnetization and differential scanning calorimetry measurements in the ferromagnetic shape memory alloy Ni 54 Fe 19 Ga 27 . This alloy undergoes an austenite-martensite phase transition in its ferromagnetic state. The nature of the ferromagnetic state, both in the austenite and the martensite phase, is studied in detail. The ferromagnetic state in the martensite phase is found to have higher anisotropy energy as compared with the austenite phase. The estimated anisotropy constant is comparable to that of a well-studied ferromagnetic shape memory alloy system NiMnGa. Further, the present study highlights various interesting features accompanying the martensitic transition (MT). These features suggest the possibility of either a premartensitic transition and/or an inter-MT in this system
Directory of Open Access Journals (Sweden)
Buket Kilicaslan
2015-09-01
Conclusion: Using a combination of procalcitonin and C-Reactive Protein is preferred to predict pyelonephritis in children, instead of the 99mTc-Dimercaptosuccinic Acid scan. Because of its disadvantages, the 99mTc-Dimercaptosuccinic Acid scan should be avoided in children. [Cukurova Med J 2015; 40(3.000: 495-503
Energy Technology Data Exchange (ETDEWEB)
Mas, P; Sciers, P; Droulers, Y [Commissariat a l' Energie Atomique. Centre d' Etudes Nucleaires, 38 - Grenoble (France)
1962-07-01
Calorimetric methods may be used to measure gamma fluxes greater than 10{sup 6} r/h near the cores of swimming pool reactors. The theory, design, and properties of isothermal calorimeters are discussed, and experimental results obtained with two types are presented. Measurement of energy deposition in materials and the long term integration of energy depositions are other uses of these devices. Results of measurements on heat deposition in steel and water are given. Fluxes were also measured. (authors) [French] Une premiere partie traite de la theorie des calorimetres isothermes mis en oeuvre au C.K.N. Grenoble. La puissance deposee dans le calorimetre par les flux de rayonnement echauffe celui-ci. L'echauffement est mesure a l'aide d'un thermocouple. On montre que l'on a ainsi une mesure absolue de cette puissance. Une deuxieme partie traite de l'etude experimentale de: deux types d'appareils utilises: leur construction, les resultats experimentaux, leurs utilisations. Trois de celles-ci sont particulierement interessantes: - la mesure des hauts flux gamma, - la mesure du depot d'energie dans les materiaux, - l'integration pendant une longue duree des depots d'energie (un modele de calorimetre a fonctionne a ce jour 2 500 heures et a integre 9 x 10 puissance 10 rads gamma et 6 x 10 puissance 18 neutrons rapides). La troisieme partie est consacree a l'etude des qualites de l'appareil: robustesse, fidelite, precision, sensibilite, gamme de mesure. Enfin dans la derniere partie sont decrites deux applications de la methode calorimetrique a la mesure du depot d'energie dans un acier special et dans l'eau. (auteurs)
Forensic Scanning Electron Microscope
Keeley, R. H.
1983-03-01
The scanning electron microscope equipped with an x-ray spectrometer is a versatile instrument which has many uses in the investigation of crime and preparation of scientific evidence for the courts. Major applications include microscopy and analysis of very small fragments of paint, glass and other materials which may link an individual with a scene of crime, identification of firearms residues and examination of questioned documents. Although simultaneous observation and chemical analysis of the sample is the most important feature of the instrument, other modes of operation such as cathodoluminescence spectrometry, backscattered electron imaging and direct x-ray excitation are also exploited. Marks on two bullets or cartridge cases can be compared directly by sequential scanning with a single beam or electronic linkage of two instruments. Particles of primer residue deposited on the skin and clothing when a gun is fired can be collected on adhesive tape and identified by their morphology and elemental composition. It is also possible to differentiate between the primer residues of different types of ammunition. Bullets may be identified from the small fragments left behind as they pass through the body tissues. In the examination of questioned documents the scanning electron microscope is used to establish the order in which two intersecting ink lines were written and to detect traces of chemical markers added to the security inks on official documents.
Calorimetric Studies on Thermal Properties of Nano-Cryoprotectant Solutions during Vitrification.
Xu, H F; Hao, B T; Liu, L J; Tang, L L; Liu, B L
BACKGROUND: Vitrification, the ice-free cryopreservation, develops rapidly and can become an ideal method for long-term preservation of cells and tissues. But up to now it is not practical for samples with large size because of the ultra-rapid cooling rate required. It has been reported that nanoparticles improve heat conductivity of solutions. In this study, Hydroxyapatite (HA) nanoparticles(20, 40 or 60nm)at 0.1 %, 0.5 % or 1 % (w/w) were added into glycerol solutions. Glass transition temperature and devitrification temperature of aqueous glycerol solutions with/without HA nanoparticles were measured by a differential scanning calorimeter(DSC) at a cooling rate of 150 degree C/min and a warming rate of 10 degree C/ min. Glass-transition temperatures and devitrification temperatures of glycerol aqueous solutions increased after the incorporation of HA nanoparticles. In the study using slow cooling rate of 10 degree C/min and warming rate of 5 degree C/min, the fraction of unfrozen water in the 50 % (w/w) glycerol solution increases steadily with the addition of HA nanoparticles. The findings have significant implications for biomaterial cryopreservation.
International Nuclear Information System (INIS)
Wang Gongke; Yan Changling; Wang Dongchao; Li Dan; Lu Yan
2012-01-01
One of the dihydropyrimidinone derivative 5-(ethoxycarbonyl)-6-methyl-4-(4-methoxyphenyl) -3,4-dihydropyrimidin-2(1H)-one (EMMD) was synthesized, and its binding properties with calf-thymus DNA (ctDNA) were investigated using spectroscopic, viscometric, isothermal titration calorimetric (ITC) and molecular modeling techniques. Fluorescence spectra suggested that the fluorescence enhancement of the binding interaction of EMMD to ctDNA was a static process with ground state complex formation. The binding constant determined with spectroscopic titration and ITC was found to be in the same order of 10 4 M −1 . According to the results of the viscosity analysis, fluorescence competitive binding experiment, fluorescence quenching studies, absorption spectral and ITC investigations, it can be concluded that EMMD is intercalative binding to ctDNA. Furthermore, the results of molecular modeling confirmed those obtained from spectroscopic, viscosimetric and ITC investigations. Additionally, ITC studies also indicated that the binding interaction is predominantly enthalpy driven. - Highlights: ► Medically important dihydropyrimidinones derivative EMMD is synthesized. ► EMMD is intercalative binding into ctDNA helix. ► Hydrogen bonding may play an essential role in the binding of EMCD with ctDNA. ► This binding interaction is predominantly enthalpy driven.
Cláudia Bernal; Andréa Boldarini Couto; Susete Trazzi Breviglieri; Éder Tadeu Gomes Cavalheiro
2002-01-01
A series of experiments were performed in order to demonstrate to undergraduate students or users of the differential scanning calorimetry (DSC), that several factors can influence the qualitative and quantitative aspects of DSC results. Saccharin, an artificial sweetner, was used as a probe and its thermal behavior is also discussed on the basis of thermogravimetric (TG) and DSC curves.
Calorimetric approach of lanthanides (3) complexation and extraction by malonamides
International Nuclear Information System (INIS)
Flandin, J.L.
2001-01-01
In the field of long lived radionuclides separation, diamides are interesting extractants because of their ability to co-extract trivalent lanthanides and actinides, which is a preliminary and essential step in high level radioactive waste reprocessing. The research carried out contributes to a better understanding of the mechanisms and the aim is the determination of thermodynamics properties (Δ r G, Δ r H et Δ r S) related to the complexation and the extraction of lanthanides(III) by malonamides. The first part of the document deals with the complexation of lanthanides(III) by an hydrosoluble diamide. The experimental results obtained by UV-visible spectrometry, TRLIF, NMR and microcalorimetric titration proved that lanthanides(III)-TEMA interactions in aqueous medium are very weak and that the complexation reaction is endothermic. The TEMA ligand still stays in the second coordination sphere of coordination of the lanthanide ion. The second part of this study focuses on the extraction of neodymium(III) nitrate by a lipophilic diamide which is an exothermic reaction. The influence of the composition of aqueous and organic phases on the thermodynamics properties Δ r G et Δ r H has been studied by microcalorimetric titration. The most influent parameter is the total concentration in extractant. As a consequence, thermodynamic values are very dependent on the organic phase organisation before and alter extraction. At the same time, this study showed the interest of the calorimetric approach for the analysis of basic reactions like diamide dilution and their organisation as oligomeric aggregates. (author)
International Nuclear Information System (INIS)
Faizal, P.K.
2009-01-01
This study has been carried out on the mixture of Gracilaria changii agar (0.1 %, 0.2 %, 0.4 % and 0.8 %) with wheat starch. Scanning electron microscopy (SEM) was performed for morphology observation, and starch thermal analysis were carried out to determine the properties of gelatinization and retrogradation. Proximate analysis has been determined for isolated wheat starch and agar. Through SEM, interaction was first observed at 64 degree Celsius for 0.4 % agar but at 0.8 % of agar, a more extensive bridging was formed which enveloped the starch granules. Differential scanning calorimetric (DSC) result shows that as the addition of agar decreased the onset temperature (T o ) of gelatinization significantly (p< 0.05) but increased the gelatinized enthalpy (ΔH gel ), gelatinized temperature range (R g ) and Peak Height Index (PHI) significantly (p < 0.05). Agar lowered the retrogradation enthalpy (ΔH ret ), retrogradation range (R ret ) and retrogradation percentage (% R) of wheat starch significantly (p < 0.05). (author)
International Nuclear Information System (INIS)
Sun, Kang; Jiang, Jian chun
2010-01-01
The use of rubber-seed shell as a raw material for the production of activated carbon with physical activation was investigated. The produced activated carbons were characterized by Nitrogen adsorption isotherms, Scanning electron microscope, Thermo-gravimetric and Differential scanning calorimetric in order to understand the rubber-seed shell activated carbon. The results showed that rubber-seed shell is a good precursor for activated carbon. The optimal activation condition is: temperature 880 o C, steam flow 6 kg h -1 , residence time 60 min. Characteristics of activated carbon with a high yield (30.5%) are: specific surface area (S BET ) 948 m 2 g -1 , total volume 0.988 m 3 kg -1 , iodine number of adsorbent (q iodine ) 1.326 g g -1 , amount of methylene blue adsorption of adsorbent (q mb ) 265 mg g -1 , hardness 94.7%. It is demonstrated that rubber-seed shell is an attractive source of raw material for producing high capacity activated carbon by physical activation with steam.
Synthesis and properties of large crystal of aluminum-deficient ultrasil molecular sieve materials
International Nuclear Information System (INIS)
Durrani, J.; Akhtar, J.; Chughtai, N.A.; Arif, M.; Saeed, K.; Ahmed, M.; Siddique, M.
2003-01-01
Large crystals of aluminum-deficient and silica rich molecular sieve materials such as Silicalite-I, Silicalite-II ZSM11-B and ZSM11-Fe have been synthesized hydro thermally from the aqueous silicate gel of (R/sub 2/O -SiO/sub 2/- B/sub 2/O/sub 3/ -Fe/sub 2/O/ sub 3/ -H/sub 2/O) using PTFE-lined stainless digestion bomb. The term R is a alkyl group. The synthesized materials were identified for crystallinity, thermal stability, phase, crystal structure, morphology and unit cell dimensions using thermogravimetry (TG/DTA), differential scanning calorimetric(DSC), X-ray diffraction (XRD), scanning electron microscopy (SEM) and other analytical techniques. All product materials were found to be white crystalline and crysto-graphically pure. Surface area and particle size distribution of materials were also ascertained. /sup 57/Fe Mossbauer spectroscopic studies on as-synthesized and calcined samples have confirmed the uniform dispersion of Fe/sup 3+/ ions in the tetrahedral framework of ZSM11-Fe material. (author)
International Nuclear Information System (INIS)
Cho, Young Jun; Kim, Joung Sook; Kim, Ji Young; Choi, Soo Jeon; Choi, Sang Bong
2008-01-01
Malignant pleural mesothelioma is an uncommon neoplasm which is accompanied extremely rarely by osteoblastic heterologous elements. The CT manifestations of this tumor have been reported in several references. And, to our knowledge, only one case report provides a description of the bone scan findings. Here, we report the case of a rapidly progressing malignant pleural mesothelioma with heterologous osteoblastic elements. A CT scan reveals diffuse irregular pleural thickening and very coarse nodular calcifications along the right pleura and major fissure. A bone scan revealed an area of extensive increased radioactivity consistent with the pleural calcifications on the CT scan in the right hemithorax. A follow-up CT scan performed 40 days later suggests the presence of rapidly progressing nodular coarse calcifications
Energy Technology Data Exchange (ETDEWEB)
Cho, Young Jun; Kim, Joung Sook; Kim, Ji Young; Choi, Soo Jeon; Choi, Sang Bong [Sanggye Paik Hospital, Inje University College of Medicine, Seoul (Korea, Republic of)
2008-06-15
Malignant pleural mesothelioma is an uncommon neoplasm which is accompanied extremely rarely by osteoblastic heterologous elements. The CT manifestations of this tumor have been reported in several references. And, to our knowledge, only one case report provides a description of the bone scan findings. Here, we report the case of a rapidly progressing malignant pleural mesothelioma with heterologous osteoblastic elements. A CT scan reveals diffuse irregular pleural thickening and very coarse nodular calcifications along the right pleura and major fissure. A bone scan revealed an area of extensive increased radioactivity consistent with the pleural calcifications on the CT scan in the right hemithorax. A follow-up CT scan performed 40 days later suggests the presence of rapidly progressing nodular coarse calcifications.
Identifying Disruptive Technologies in Design: Horizon Scanning in the Early Stages of Design
DEFF Research Database (Denmark)
Ernstsen, Sidsel Katrine; Thuesen, Christian; Larsen, Laurids Rolighed
Technology development is accelerating, driving disruption. Design is seen as key differentiator in creating innovative offerings but few design methods consider future technologies explicitly. In this article, we explore how a foresight method, namely horizon scanning, may be applied in a design...... context to anticipate disruption of construction. By means of a 3-step horizon scan, we identify 133 potentially disruptive technologies from across industries. We find that when preparing for disruption, design may benefit from the future-oriented and technology-focused features of horizon scanning....
Directory of Open Access Journals (Sweden)
Yunfei Wang
2015-06-01
Full Text Available A class of carboxyl and carboxylate ester-substituted dithiafulvene (DTF derivatives and tetrathiafulvalene vinylogues (TTFVs has been synthesized and their electronic and electrochemical redox properties were characterized by UV–vis spectroscopic and cyclic voltammetric analyses. The carboxyl-TTFV was applied as a redox-active ligand to complex with Zn(II ions, forming a stable Zn-TTFV coordination polymer. The structural, electrochemical, and thermal properties of the coordination polymer were investigated by infrared spectroscopy, cyclic voltammetry, powder X-ray diffraction, and differential scanning calorimetric analyses. Furthermore, the microscopic porosity and surface area of the Zn-TTFV coordination polymer were measured by nitrogen gas adsorption analysis, showing a BET surface of 148.2 m2 g−1 and an average pore diameter of 10.2 nm.
Directory of Open Access Journals (Sweden)
Gabriel Ordaz González
2017-11-01
Full Text Available Oil from seeds of Anacardium occidentale L. (cashew nut was obtained by Soxhlet solvent extraction using hexane with a 26% yield. Concentrations of this oil lower than 1000 μg·mL-1 were innocuous in the lethality bioassay against Artemia salina. Analysis of Differential Scanning Calorimetric (DSC of this oil exhibited a wide melting range (Tonset = -22.60ºC, Tpico = -12.27ºC, which could be associated with the content of unsaturated fatty acids (76.24%. The oil showed thermal stability between 20 and 100ºC. The GC-MS analysis allowed to identify oleic (C18:1, ω-9, 51.3% and linoleic (C18:2, ω-6, 24.88% acids as major constituents.
International Nuclear Information System (INIS)
Zulfiqar, Sonia; Ahmad, Zahoor; Ishaq, Muhammad; Sarwar, Muhammad Ilyas
2009-01-01
New type of aromatic-aliphatic polyamide/montmorillonite nanocomposites were produced using solution intercalation technique in dimethylacetamide. The modification of clay was carried out with ammonium salt of long chain alkyl amine. The nanocomposites were probed for organoclay dispersion, mechanical, thermal and water absorption measurements. Formation of delaminated and intercalated nanostructures was confirmed by X-ray diffraction and TEM studies. Improvement in tensile strength and modulus was observed for nanocomposites with optimum organoclay content (8-wt.%). Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. Differential scanning calorimetric results revealed increase in glass transition temperatures (T g ) with augmenting organoclay in the nanocomposites. Water uptake of the nanocomposites reduced than the neat polyamide rendering decreased permeability.
Energy Technology Data Exchange (ETDEWEB)
Zulfiqar, Sonia [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Ahmad, Zahoor [Department of Chemistry, Faculty of Science, Kuwait University, P. O. Box: 5969, Safat 13060 (Kuwait); Ishaq, Muhammad [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Sarwar, Muhammad Ilyas, E-mail: ilyassarwar@hotmail.com [Department of Chemistry, Quaid-i-Azam University, Islamabad 45320 (Pakistan); Department of Materials Science and Engineering, University of Delaware, Newark, DE 19716 (United States)
2009-11-15
New type of aromatic-aliphatic polyamide/montmorillonite nanocomposites were produced using solution intercalation technique in dimethylacetamide. The modification of clay was carried out with ammonium salt of long chain alkyl amine. The nanocomposites were probed for organoclay dispersion, mechanical, thermal and water absorption measurements. Formation of delaminated and intercalated nanostructures was confirmed by X-ray diffraction and TEM studies. Improvement in tensile strength and modulus was observed for nanocomposites with optimum organoclay content (8-wt.%). Thermogravimetric analysis indicated an increase in thermal stability of nanocomposites as compared to pristine polyamide. Differential scanning calorimetric results revealed increase in glass transition temperatures (T{sub g}) with augmenting organoclay in the nanocomposites. Water uptake of the nanocomposites reduced than the neat polyamide rendering decreased permeability.
International Nuclear Information System (INIS)
Román, Frida; Calventus, Yolanda; Colomer, Pere; Hutchinson, John M.
2012-01-01
Highlights: ► Comparison of DSC and DRS in the cure of epoxy nanocomposites. ► Dependence of exfoliation of nanocomposite on clay content. ► Anionically initiated homopolymerisation in PLS nanocomposites. - Abstract: The effect of nanoclay on the non-isothermal cure kinetics of polymer layered silicate nanocomposites based upon epoxy resin is studied by calorimetric techniques (DSC and TGA) and by dielectric relaxation spectroscopy (DRS) in non-isothermal cure at constant heating rate. The cure process takes place by homopolymerisation, initiated anionically using 3 wt% dimethylaminopyridine (DMAP), and the influence of the nanoclay content has been analysed. Interesting differences are observed between the nanocomposites with 2 wt% and 5 wt% clay content. At low heating rates, these samples vitrify and then devitrify during the cure. For the sample with 2 wt% clay, the devitrification is accompanied by a thermally initiated homopolymerisation, which can be identified by DRS but not by DSC. The effect of this is to improve the exfoliation of the nanocomposite with 2 wt% clay, as verified by transmission electron microscopy, with a corresponding increase in the glass transition temperature. These observations are interpreted in respect of the nanocomposite preparation method and the cure kinetics.
Flash Glucose Monitoring: Differences Between Intermittently Scanned and Continuously Stored Data.
Pleus, Stefan; Kamecke, Ulrike; Link, Manuela; Haug, Cornelia; Freckmann, Guido
2018-03-01
The flash glucose monitoring system FreeStyle Libre (Abbott Diabetes Care Ltd., Witney, UK) measures interstitial glucose concentrations and continuously stores measurement values every 15 minutes. To obtain a current glucose reading, users have to scan the sensor with the reader. In a clinical trial, 5% of the scanned data showed relative differences of more than ±10% compared with continuously stored data points (median -0.5%). Such differences might impact results of studies using this system. It should be indicated whether scanned or continuously stored data were used for analyses. Health care professionals might have to differentiate between data reports from clinical software and the scanned data their patients are provided with. Additional information on these differences and their potential impact on therapeutic decisions would be helpful.
Calorimetric studies of the thermal denaturation of cytochrome c peroxidase
International Nuclear Information System (INIS)
Kresheck, G.C.; Erman, J.E.
1988-01-01
Two endotherms are observed by differential scanning calorimetry during the thermal denaturation of cytochrome c peroxidase at pH 7.0. The transition midpoint temperatures (t/sub m/) were 43.9 +- 1.4 and 63.3 +- 1.6 0 C, independent of concentration. The two endotherms were observed at all pH values between 4 and 8, with the transition temperatures varying with pH. Precipitation was observed between pH 4 and 6, and only qualitative data are presented for this region. The thermal unfolding of cytochrome c peroxidase was sensitive to the presence and ligation state of the heme. Only a single endotherm was observed for the unfolding of the apoprotein, and this transition was similar to the high-temperature transition in the holoenzyme. Addition of KCN to the holoenzyme increases the midpoint of the high-temperature transition whereas the low-temperature transition was increased upon addition of KF. Binding of the natural substrate ferricytochrome c to the enzyme increases the low-temperature transition by 4.8 +- 1.3 0 C but has no effect on the high-temperature transition at pH 7. The presence of cytochrome c peroxidase decreases the stability of cytochrome c, and both proteins appear to unfold simultaneously. The results are discussed in terms of the two domains evident in the X-ray crystallographic structure of cytochrome c peroxidase
Directory of Open Access Journals (Sweden)
Stéphane Gibout
2018-01-01
Full Text Available Modeling the thermal behavior of a plant or devices using Phase Change Materials (PCM requires to know their thermophysical properties. The Differential Scanning Calorimetry (DSC is a technic largely used to investigate them. However, under the pretext to experiment with small samples, some authors consider the DSC curves as directly representing the properties of the materials without realizing that this interpretation is very often incompatible with the thermodynamics laws: as an example, although a pure substance melts at a fixed temperature T F , it is proposed a melting through a temperature range higher than T F and depending on the experiments (heating rates, sample masses..., for solutions the suggested characteristic temperatures are incompatible with the phase diagram, and also a hysteresis phenomenon is invented... In this paper, we demonstrate by a model coupling thermodynamics and conduction heat transfers, that the DSC curves are exactly compatible with the thermodynamics of phase changes (melting at fixed temperature for pure substances, in conformity with phase diagrams for solutions.... The cases of pure substances, saline solutions, substances with impurities or solid solutions are detailed. We indicate which information can, however, be given by the curves. We also propose a more sophisticated method by inverse calculations to determine the specific enthalpy whose all the thermodynamical properties can be deduced. Finally, we give some indications to understand and use the results indicating supercooling.
Detection of structural heterogeneity of glass melts
DEFF Research Database (Denmark)
Yue, Yuanzheng
2004-01-01
The structural heterogeneity of both supercooled liquid and molten states of silicate has been studied using calorimetric method. The objects of this study are basaltic glasses and liquids. Two experimental approaches are taken to detect the structural heterogeneity of the liquids. One is the hyp......The structural heterogeneity of both supercooled liquid and molten states of silicate has been studied using calorimetric method. The objects of this study are basaltic glasses and liquids. Two experimental approaches are taken to detect the structural heterogeneity of the liquids. One...... is the hyperquench-anneal-calorimetric scan approach, by which the structural information of a basaltic supercooled liquid and three binary silicate liquids is acquired. Another is the calorimetrically repeated up- and downscanning approach, by which the structural heterogeneity, the intermediate range order...... is discussed. The ordered structure of glass melts above the liquidus temperature is indirectly characterized by use of X-ray diffraction method. The new approaches are of importance for monitoring the glass melting and forming process and for improving the physical properties of glasses and glass fibers....
Diagnosis of gynecologic pelvic masses by CT scans
International Nuclear Information System (INIS)
Ito, Hisao; Kubo, Atsushi; Takagi, Yaeko; Kinoshita, Fumio; Maekawa, Akira.
1981-01-01
Two hundred eighty four patients with gynecologic pelvic masses were evaluated with CT scans. Of the patients, 196 had subsequent surgical determination of abnormalities and pathological proof of diagnosis was obtained. Only these 196 patients were included in this study. The CT scans could provide correct diagnosis in 113 of 114 (99%) patients with benign uterine tumor and in all (100%) patients with either serous cystadenoma or dermoid cyst. However, evaluation of mucinous cystadenoma (44%) and endometriosis cyst (37%) by CT scan has some limitations. It was difficult to differentiate mucinous cystadenoma from ovarian carcinoma, because both lesions had partial multiloculation and solid-like areas in the cyst. The CT findings of endometriosis cyst had similarity with serous cystadenoma, and 5 of 8 patients with this disease were diagnosed as serous cystadenoma. Ovarian fibroma and endometrial cancer were also not determined by CT scans. CT identified 87% of patients with ovarian cancer, while false positive rate of this disease was 38% (8/21). In 6 of 13 patients with both of leiomyoma and ovarian cyst, CT was able to demonstrate ovarian lesions that were overlooked by bimanual examinations. The role of CT scanning in our clinical practice is discussed. (author)
International Nuclear Information System (INIS)
Toscani, S.; Cornevin, L.; Burgot, G.
2012-01-01
Highlights: ► Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. ► Energy-barrier decrease for lactose dehydration induced by clobazam. ► Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. ► Decrease of lactose dehydration temperature in binary mixtures with captopril. ► Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous α-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril–lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.
Glass transition of anhydrous starch by fast scanning calorimetry.
Monnier, Xavier; Maigret, Jean-Eudes; Lourdin, Denis; Saiter, Allisson
2017-10-01
By means of fast scanning calorimetry, the glass transition of anhydrous amorphous starch has been measured. With a scanning rate of 2000Ks -1 , thermal degradation of starch prior to the glass transition has been inhibited. To certify the glass transition measurement, structural relaxation of the glassy state has been investigated through physical aging as well as the concept of limiting fictive temperature. In both cases, characteristic enthalpy recovery peaks related to the structural relaxation of the glass have been observed. Thermal lag corrections based on the comparison of glass transition temperatures measured by means of differential and fast scanning calorimetry have been proposed. The complementary investigations give an anhydrous amorphous starch glass transition temperature of 312±7°C. This estimation correlates with previous extrapolation performed on hydrated starches. Copyright © 2017 Elsevier Ltd. All rights reserved.
Guidance for reading FDG PET scans in dementia patients
International Nuclear Information System (INIS)
Herholz, K.
2014-01-01
18F-2-fluoro-2-deoxy-D-glucose (FDG) positron emission tomography (PET) is a powerful method for detection of disease-related impairment of cerebral glucose metabolism in neuro degenerative diseases. It is of particular interest for early and differential diagnosis of dementia. Reading FDG PET scans requires training to recognise deviations from normal functional brain anatomy and its variations. This paper provides guidance for displaying FDG PET brain scans in a reproducible manner that allows reliable recognition of characteristic disease-related metabolic changes. It also describes typical findings in Alzheimer’s disease, Frontotemporal Dementia and Dementia with Lewy Bodies and possible confounding factors, such as vascular changes and brain atrophy. It provides a brief overview on findings in other neuro degenerative diseases and addresses the potential and limitations of software packages for comparison of individual scans with reference data.
F-18 FDG PET scan findings in patients with pulmonary involvement in the hypereosinophilic syndrome
Energy Technology Data Exchange (ETDEWEB)
Lee, Jae Hoon; Kim, Tae Hoon; Yun, Mi Jin [College of Medicine, Yonsei University, Seoul (Korea, Republic of)] (and others)
2005-08-15
Hypereosinophilic syndrome (HES) is an infiltrative disease of eosinophils affecting multiple organs including the lung. F-18 2-fluoro-2-deoxyglucose (F-18 FDG) may accumulate at sites of inflammation or infection, making interpretation of whole body PET scan difficult in patients with cancer. This study was to evaluate the PET findings of HES with lung involvement and to find out differential PET features between lung malignancy and HES with lung involvement. F-18 FDG PET and low dose chest CT scan was performed for screening of lung cancer. Eight patients who showed ground-glass attenuation (GGA) and consolidation on chest CT scan with peripheral blood eosinophilia were included in this study. The patients with history of parasite infection, allergy and collagen vascular disease were excluded. CT features and FDG PET findings were meticulously evaluated for the distribution of GGA and consolidation and nodules on CT scan and mean and maximal SUV of abnormalities depicted on F-18 FDG PET scan. In eight patients, follow-up chest CT scan and FDG PET scan were done one or two weeks after initial study. F-18 FDG PET scan identified metabolically active lesions in seven out of eight patients. Maximal SUV was ranged from 2.8 to 10.6 and mean SUV was ranged from 2.2 to 7.2. Remaining one patient had maximal SUV of 1.3. On follow-up FDG PET scan taken on from one to four weeks later showed decreased degree of initially noted FDG uptakes or migration of previously noted abnormal FDG uptakes. Lung involvement in the HES might be identified as abnormal uptake foci on FDG PET scan mimicking lung cancer. Follow-up FDG PET and CT scan for the identification of migration or resolution of abnormalities and decrement of SUV would be of help for the differentiation between lung cancer and HES with lung involvement.
F-18 FDG PET scan findings in patients with pulmonary involvement in the hypereosinophilic syndrome
International Nuclear Information System (INIS)
Lee, Jae Hoon; Kim, Tae Hoon; Yun, Mi Jin
2005-01-01
Hypereosinophilic syndrome (HES) is an infiltrative disease of eosinophils affecting multiple organs including the lung. F-18 2-fluoro-2-deoxyglucose (F-18 FDG) may accumulate at sites of inflammation or infection, making interpretation of whole body PET scan difficult in patients with cancer. This study was to evaluate the PET findings of HES with lung involvement and to find out differential PET features between lung malignancy and HES with lung involvement. F-18 FDG PET and low dose chest CT scan was performed for screening of lung cancer. Eight patients who showed ground-glass attenuation (GGA) and consolidation on chest CT scan with peripheral blood eosinophilia were included in this study. The patients with history of parasite infection, allergy and collagen vascular disease were excluded. CT features and FDG PET findings were meticulously evaluated for the distribution of GGA and consolidation and nodules on CT scan and mean and maximal SUV of abnormalities depicted on F-18 FDG PET scan. In eight patients, follow-up chest CT scan and FDG PET scan were done one or two weeks after initial study. F-18 FDG PET scan identified metabolically active lesions in seven out of eight patients. Maximal SUV was ranged from 2.8 to 10.6 and mean SUV was ranged from 2.2 to 7.2. Remaining one patient had maximal SUV of 1.3. On follow-up FDG PET scan taken on from one to four weeks later showed decreased degree of initially noted FDG uptakes or migration of previously noted abnormal FDG uptakes. Lung involvement in the HES might be identified as abnormal uptake foci on FDG PET scan mimicking lung cancer. Follow-up FDG PET and CT scan for the identification of migration or resolution of abnormalities and decrement of SUV would be of help for the differentiation between lung cancer and HES with lung involvement
Calorimetric measurement of heat load in full non-inductive LHCD plasmas on TRIAM-1M
International Nuclear Information System (INIS)
Hanada, K.; Shinoda, N.; Sugata, T.; Sasaki, K.; Zushi, H.; Nakamura, K.; Sato, K.N.; Sakamoto, M.; Idei, H.; Hasegawa, M.; Kawasaki, S.; Nakashima, H.; Higashijima, A.
2007-01-01
Calorimetric measurements using the temperature increment of cooling-water were carried out to estimate the heat load distribution on the plasma facing components (PFCs) in the limiter discharges on TRIAM-1M. Line averaged electron density, n e , and LH power, P LH , dependences of the heat load on PFCs were measured. The heat load on the limiters was proportional to n e 1.5 in the range of n e =0.2-1.0x10 19 m -3 and P LH 1 in the range of P LH =0.005-0.09MW. For P LH >0.1MW, the plasma transition to an enhanced current drive (ECD) mode appeared and the n e dependences on the heat load on the limiter moderated. This indicates that the heat flux to scrape-off layer (SOL) region was reduced due to the improvement of the plasma confinement. The up-down asymmetry of the heat load on the vacuum vessel was enhanced in the ECD mode, which may be caused by the increasing of the direct loss of energetic electrons
a Calorimetric Study of the Precipitation Hardening Mechanisms in AN Al-Cu-Mg-Si Alloy
Hayoune, Abdelali
2013-08-01
The precipitation phenomena and the related hardening in an Al-Cu-Mg-Si alloy were studied by calorimetry, X-ray diffraction analysis and microhardness measurements. The main calorimetric peaks were identified to be due to β‧‧, θ‧ and Q‧ phases precipitation. The hardening during aging at room temperature and 160°C, was respectively, explained by atomic clusters and GP zones formation and by GP zones and β‧‧/θ‧ phases coprecipitation. Although the mechanical properties variation during aging at 200°C is simple, the corresponding microstructural evolution is complex: on the basis of the DSC results, the increasing of microhardness values, is mainly due to the coprecipitation of GP zones and β‧‧/θ‧ phases, however, the maximum hardening is explained by the coexistence of β‧‧/θ‧ and θ‧‧ phases. Another important conclusion is that during aging at 160°C and 200°C, the θ‧ phase is essentially developed from GP zones.
Concurrent Driving Method with Fast Scan Rate for Large Mutual Capacitance Touch Screens
Directory of Open Access Journals (Sweden)
Mohamed Gamal Ahmed Mohamed
2015-01-01
Full Text Available A novel touch screen control technique is introduced, which scans each frame in two steps of concurrent multichannel driving and differential sensing. The proposed technique substantially increases the scan rate and reduces the ambient noise effectively. It is also extended to a multichip architecture to support excessively large touch screens with great scan rate improvement. The proposed method has been implemented using 0.18 μm CMOS TowerJazz process and tested with FPGA and AFE board connecting a 23-inch touch screen. Experimental results show a scan rate improvement of up to 23.8 times and an SNR improvement of 24.6 dB over the conventional method.
Masum, Abdulla Al; Chakraborty, Maharudra; Pandya, Prateek; Halder, Umesh Chandra; Islam, Md Maidul; Mukhopadhyay, Subrata
2014-11-20
In this paper, the interaction of rhodamine123 (R123) with calf thymus DNA has been studied using molecular modeling and other biophysical methods like UV-vis spectroscopy, fluoremetry, optical melting, isothermal titration calorimetry, and circular dichroic studies. Results showed that the binding energy is about -6 to -8 kcal/mol, and the binding process is favored by both negative enthalpy change and positive entropy change. A new method to determine different thermodynamic properties like calorimetric enthalpy and heat capacity change has been introduced in this paper. The obtained data has been crossed-checked by other methods. After dissecting the free-energy contribution, it was observed that the binding was favored by both negative hydrophobic free energy and negative molecular free energy which compensated for the positive free energies due to the conformational change loss of rotational and transitional freedom of the DNA helix.
Energy Technology Data Exchange (ETDEWEB)
Guerra, Denis L., E-mail: dlguerra@pq.cnpq.br [Universidade Federal de Mato Grosso, DRM, UFMT, Mato Grosso 78060 900 (Brazil); Batista, Adriano C. [Universidade Estadual do Norte Fluminense, UENF, Rio de Janeiro 28013 02 (Brazil); Viana, Rubia R. [Universidade Federal de Mato Grosso, DRM, UFMT, Mato Grosso 78060 900 (Brazil); Airoldi, Claudio [Chemistry Institute, State University of Campinas, PO Box 6154, 13084-971 Campinas, Sao Paulo (Brazil)
2010-11-15
The synthetic imogolite sample was used for organofunctionalization process with 2-mercaptothiazoline (MTZ). The compound 2-mercaptothiazoline was anchored onto imogolite surface by heterogeneous route. Due to the increment of basic centers attached to the pendant chains the dye adsorption capability of the final chelating material, was found to be higher than is precursor. The ability of these materials to remove methylene blue from aqueous solution was followed by a series of adsorption isotherms at room temperature and pH 4.0. The maximum number of moles adsorbed was determined to be 40.32 x 10{sup -2} and 65.13 x 10{sup -2} mmol g{sup -1} for IMO and IMO{sub MTZ}, respectively. The energetic effects caused by dye cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such methylene blue-nitrogen and sulfur interactions.
Early appearance of SARS on chest CT scan
International Nuclear Information System (INIS)
Cheng Xiaoguang; Feng Suchen; Xia Guoguang; Zhao Tao; Gu Xiang; Qu Hui
2003-01-01
Objective: To evaluate the early appearance of SARS on chest CT scan and its role in the early diagnosis. Methods: Forty cases of SARS in keeping with the criteria of the Ministry of Health had chest CT scans within 7 days of onset of symptoms, and CR chest X-ray films were available as well. These chest X-rays and CT images were retrospectively reviewed to determine if there were any abnormalities on the images. The lesions on the chest CT images were then further analyzed in terms of the number, location, size, and density. Results: Positive abnormalities on chest CT scans were revealed in all 40 SARS cases. Positive findings on CR chest films were showed in only 25 cases, equivocal in 6, and normal in 9 cases. The main abnormalities seen on CT and X-rays were pulmonary infiltrations varied markedly in severity. 70 % cases had 1 or 2 lesions on chest CT scan, 30 % cases had 3 or more lesions. The lesions seen on chest CT scan tended to be ground-glass opacification, sometimes with consolidation which was very faint and inhomogeneous, easily missed on chest X-rays. Typically the lesions were located in the periphery of the lung, or both central and peripheral lung, but very rare in a pure central location. They were commonly in the shape of patch or ball. Conclusions: Chest CT scan is much more sensitive in detecting the lesions of the lung in SARS. The early appearance of SARS on chest CT scan is characteristic but non-specific, indicating that chest CT scan plays a very important role in the early diagnosis and differential diagnosis of SARS
Sundaramurthi, Prakash; Shalaev, Evgenyi; Suryanarayanan, Raj
2010-04-15
Sequential crystallization of succinate buffer components in the frozen solution has been studied by differential scanning calorimetry and X-ray diffractometry (both laboratory and synchrotron sources). The consequential pH shifts were monitored using a low-temperature electrode. When a solution buffered to pH pK(a)(2), the freeze-concentrate pH first decreased and then increased due to the sequential crystallization of the basic (disodium succinate) followed by the acidic (monosodium succinate and succinic acid) buffer components. XRD provided direct evidence of the crystallization events in the frozen buffer solutions, including the formation of disodium succinate hexahydrate [Na(2)(CH(2)COO)(2).6H(2)O]. When the frozen solution was warmed in a differential scanning calorimeter, multiple endotherms attributable to the melting of buffer components and ice were observed. When the frozen solutions were dried under reduced pressure, ice sublimation was followed by dehydration of the crystalline hexahydrate to a poorly crystalline anhydrate. However, crystalline succinic acid and monosodium succinate were retained in the final lyophiles. The pH and the buffer salt concentration of the prelyo solution influenced the crystalline salt content in the final lyophile. The direction and magnitude of the pH shift in the frozen solution depended on both the initial pH and the buffer concentration. In light of the pH-sensitive nature of a significant fraction of pharmaceuticals (especially proteins), extreme care is needed in both the buffer selection and its concentration.
Roth, Jonathan V; Sea, Stephanie
2014-06-01
Heat transfer from a patient to warm and humidify insufflated carbon dioxide (CO2) during laparoscopic surgery may contribute to perioperative hypothermia. The magnitude of this effect was calculated using calorimetric calculations. Warming to 37°C and humidifying to 100%, each 100 L of insufflated CO2 would prevent a heat transfer of 3220 calories, which would result in a decrease of temperature by 0.06°C in a 70 kg patient after total body distribution of heat. We conclude that the thermal benefit of warming and humidifying insufflated CO2 is minor, particularly in comparison with other effective and inexpensive perioperative technologies, some of which are not always used out could easily be used. The decision to use heating and humidification of insufflated CO2 should be based on its other risks, benefits, and costs.
Energy Technology Data Exchange (ETDEWEB)
Ayela, F; Derrien, H [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires
1962-07-01
It has been possible with the calorimeter of which we give the principle and details in the present report, to determine the calorific power produced by nuclear radiation in a given sample using simple electrical measurement. It also renders unnecessary all absolute measurements of temperature, all possible calibration, and the use of the thermal or thermoelectric constants of the constituent elements. The possible uses of the apparatus are fairly varied, as shown by the first in-pile experiments which we have carried out and for which we give results. (authors) [French] Le calorimetre, dont nous decrivons le principe et les details dans le present rapport, nous permet de determiner, par de simples mesures electriques, la puissance calorifique liberee par les rayonnements nucleaires dans un echantillon donne. Il nous affranchit aussi, de toute mesure absolue de temperature, de tout etalonnage prealable, et de l'utilisation des constantes thermiques ou thermoelectriques de ses elements constitutifs. Les possibilites d'emploi de l'appareil sont assez variees comme nous le montrent les premiers essais que nous avons effectues en pile et dont nous donnons les resultats. (auteurs)
Mallamace, Domenico; Vasi, Sebastiano; Corsaro, Carmelo; Naccari, Clara; Clodoveo, Maria Lisa; Dugo, Giacomo; Cicero, Nicola
2017-11-01
The thermal properties of many organic extra Virgin Olive Oils (eVOOs) coming from different countries of the world were investigated by Differential Scanning Calorimetry (DSC). This technique, through a series of heating and cooling cycles, provides a specific curve, i.e., a thermogram, which represents the fingerprint of each eVOO sample. In fact, variations due to the different cultivars, geographical origin or chemical composition can be highlighted because they produce changes in the corresponding thermogram. In particular, in this work, we show the results of an unsupervised multivariate statistical analysis applied to the DSC thermograms of many organic eVOOs. This analysis allows us to discriminate the geographical origin of the different studied samples in terms of the peculiar features shown by the melting profiles of the triacylglycerol moieties.
Mattersdorfer, Karin; Koblmüller, Stephan; Sefc, Kristina M
2012-07-01
Genome scan-based tests for selection are directly applicable to natural populations to study the genetic and evolutionary mechanisms behind phenotypic differentiation. We conducted AFLP genome scans in three distinct geographic colour morphs of the cichlid fish Tropheus moorii to assess whether the extant, allopatric colour pattern differentiation can be explained by drift and to identify markers mapping to genomic regions possibly involved in colour patterning. The tested morphs occupy adjacent shore sections in southern Lake Tanganyika and are separated from each other by major habitat barriers. The genome scans revealed significant genetic structure between morphs, but a very low proportion of loci fixed for alternative AFLP alleles in different morphs. This high level of polymorphism within morphs suggested that colour pattern differentiation did not result exclusively from neutral processes. Outlier detection methods identified six loci with excess differentiation in the comparison between a bluish and a yellow-blotch morph and five different outlier loci in comparisons of each of these morphs with a red morph. As population expansions and the genetic structure of Tropheus make the outlier approach prone to false-positive signals of selection, we examined the correlation between outlier locus alleles and colour phenotypes in a genetic and phenotypic cline between two morphs. Distributions of allele frequencies at one outlier locus were indeed consistent with linkage to a colour locus. Despite the challenges posed by population structure and demography, our results encourage the cautious application of genome scans to studies of divergent selection in subdivided and recently expanded populations. © 2012 Blackwell Publishing Ltd.
International Nuclear Information System (INIS)
Kestens, V.; Zeleny, R.; Auclair, G.; Held, A.; Roebben, G.; Linsinger, T.P.J.
2011-01-01
Highlights: → Purity assessment of polycyclic aromatic hydrocarbons and chloramphenicol by DSC. → DSC results compared with traditional purity methods. → Different methods give different results, multiple method approach recommended. → DSC sensitive to impurities that have similar structures as main component. - Abstract: In this study the validity and suitability of differential scanning calorimetry (DSC) to determine the purity of selected polycyclic aromatic hydrocarbons and chloramphenicol has been investigated. The study materials were two candidate certified reference materials (CRMs), 6-methylchrysene and benzo[a]pyrene, and two different batches of commercially available highly pure chloramphenicol. The DSC results were compared with those obtained by other methods, namely gas and liquid chromatography with mass spectrometric detection, liquid chromatography with diode array detection, and quantitative nuclear magnetic resonance. The purity results obtained by these different analytical methods confirm the well-known challenges of comparing results of different method-defined measurands. In comparison with other methods, DSC has a much narrower working range. This limits the applicability of DSC as purity determination method, for instance during the assignment of the purity value of a CRM. Nevertheless, this study showed that DSC can be a powerful technique to detect impurities that are structurally very similar to the main purity component. From this point of view, and because of its good repeatability, DSC can be considered as a valuable technique to investigate the homogeneity and stability of candidate purity CRMs.
Wang, T. X.; Huang, W. M.
2017-12-01
The recent development in the temperature memory effect (TME) via differential scanning calorimetry in shape memory alloys is briefly discussed. This phenomenon was also called the thermal arrest memory effect in the literature. However, these names do not explicitly reveal the potential application of this phenomenon in temperature monitoring. On the other hand, the standard testing process of the TME has great limitation. Hence, it cannot be directly applied for temperature monitoring in most of the real engineering applications in which temperature fluctuation occurs mostly in a random manner within a certain range. However, as shown here, after proper modification, we are able to monitor the maximum or minimum temperature in either over-heating or over-cooling with reasonable accuracy.
Energy Technology Data Exchange (ETDEWEB)
Roman, Frida, E-mail: roman@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain); Calventus, Yolanda, E-mail: calventus@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain); Colomer, Pere, E-mail: colomer@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain); Hutchinson, John M., E-mail: hutchinson@mmt.upc.edu [Laboratori de Termodinamica, Departament de Maquines i Motors Termics, ETSEIAT, Universitat Politecnica de Catalunya, Carrer Colom 11, 08222 Terrassa (Spain)
2012-08-10
Highlights: Black-Right-Pointing-Pointer Comparison of DSC and DRS in the cure of epoxy nanocomposites. Black-Right-Pointing-Pointer Dependence of exfoliation of nanocomposite on clay content. Black-Right-Pointing-Pointer Anionically initiated homopolymerisation in PLS nanocomposites. - Abstract: The effect of nanoclay on the non-isothermal cure kinetics of polymer layered silicate nanocomposites based upon epoxy resin is studied by calorimetric techniques (DSC and TGA) and by dielectric relaxation spectroscopy (DRS) in non-isothermal cure at constant heating rate. The cure process takes place by homopolymerisation, initiated anionically using 3 wt% dimethylaminopyridine (DMAP), and the influence of the nanoclay content has been analysed. Interesting differences are observed between the nanocomposites with 2 wt% and 5 wt% clay content. At low heating rates, these samples vitrify and then devitrify during the cure. For the sample with 2 wt% clay, the devitrification is accompanied by a thermally initiated homopolymerisation, which can be identified by DRS but not by DSC. The effect of this is to improve the exfoliation of the nanocomposite with 2 wt% clay, as verified by transmission electron microscopy, with a corresponding increase in the glass transition temperature. These observations are interpreted in respect of the nanocomposite preparation method and the cure kinetics.
Grajzer, Magdalena; Prescha, Anna; Korzonek, Katarzyna; Wojakowska, Anna; Dziadas, Mariusz; Kulma, Anna; Grajeta, Halina
2015-12-01
Two new commercially available high linolenic oils, pressed at low temperature from rose hip seeds, were characterised for their composition, quality and DPPH radical scavenging activity. The oxidative stability of oils was assessed using differential scanning calorimetry (DSC). Phytosterols, tocopherols and carotenoids contents were up to 6485.4; 1124.7; and 107.7 mg/kg, respectively. Phenolic compounds determined for the first time in rose hip oil totalled up to 783.55 μg/kg, with a predominant presence of p-coumaric acid methyl ester. Antiradical activity of the oils reached up to 3.00 mM/kg TEAC. The acid, peroxide and p-anisidine values as well as iron and copper contents indicated good quality of the oils. Relatively high protection against oxidative stress in the oils seemed to be a result of their high antioxidant capacity and the level of unsaturation of fatty acids. Copyright © 2015 Elsevier Ltd. All rights reserved.
Directory of Open Access Journals (Sweden)
Virgilio Tattini Jr
2007-03-01
Full Text Available Bovine pericardium bioprosthesis has become a commonly accepted device for heart valve replacement. Present practice relies on the measurement of shrinkage temperature, observed as a dramatic shortening of tissue length. Several reports in the last decade have utilized differential scanning calorimetry (DSC as an alternative method to determine the shrinkage temperature, which is accompanied by the absorption of heat, giving rise to an endothermic peak over the shrinkage temperature range of biological tissues. Usually, freeze-drying microscope is used to determine collapse temperature during the lyophilization of solutions. On this experiment we used this technique to study the shrinkage event. The aim of this work was to compare the results of shrinkage temperature obtained by DSC with the results obtained by freeze-drying microscopy. The results showed that both techniques provided excellent sensitivity and reproducibility, and gave information on the thermal shrinkage transition via the thermodynamical parameters inherent of each method.
Directory of Open Access Journals (Sweden)
Rafael Bergamo Trinca
2009-01-01
Full Text Available The high cost of sensitivity commercial calorimeters may represent an obstacle for many calorimetric research groups. This work describes the construction and calibration of a batch differential heat conduction calorimeter with sample cells volumes of about 400 μL. The calorimeter was built using two small high sensibility square Peltier thermoelectric sensors and the total cost was estimated to be about US$ 500. The calorimeter was used to study the excess enthalpy of solution of binary mixtures of liquids, as a function of composition, for the following binary systems of solvents: water + 1,4-dioxane or + dimethylsulfoxide at 298,2 ± 0,5 K.
Ruiz Franco-Baux, J V; Borrego Dorado, I; Gómez Camarero, P; Rodríguez Rodríguez, J R; Vázquez Albertino, R J; Navarro González, E; Astorga Jiménez, R
2005-01-01
This study aimed to evaluate the role of Fluorine-18-fluorodeoxyglucose positron emission tomography (PET-FDG) in patients with elevated serum thyroglobulin (hTg) levels where thyroid cancer tissue does not concentrate radioiodine, rendering false-negative results on I-131 scanning. Whole-body PET imaging using FDG was performed in 54 patients (37 female, 17 male) aged 17-88 years: 45 with papillary tumors and 9 with follicular tumors who were suspected of having recurrent thyroid carcinoma due to elevated thyroglobulin levels (hTg > 2 ng/ml) under thyroid-stimulating hormone (TSH > or = 30 microIU/ml) in whom the iodine scan was negative. All whole body scans were obtained with diagnostic doses (185 MBq). Whole body PET imaging was performed in fasting patients following i.v. administration of 370 MBq FDG while the patients were receiving full thyroid hormone replacement. Before PET, 99mTc methoxyisobutylisonitrile scintigraphy (99mTc-MIBI) was done in 14 patients and morphologic imaging in 26 by CT scan. Positive PET results confirmed the presence of hypermetabolic foci in 25/54 patients (46.29 %). Positive findings were found for PET-FDG in patients with hTg levels higher than 10 ng/ml receiving full thyroid hormone replacement. 99mTc-MIBI demonstrated lesions in 7/14 patients (50 %). PET-FDG and 99mTc-MIBI had congruent positive results in 4/7 patients. All the lesions found by CT were detected by PET-FDG, while recurrent disease was found in 12/21 patients with previous negative CT. These results suggest that PET-FDG seems to be a promising tool in the follow-up of thyroid cancer and should be considered in patients suffering from differentiated thyroid cancer with suspected recurrence and/or metastases by elevated thyroglobulin levels, and negative I-131 whole body scans. PET-FDG might be more useful at hTg levels > 10 ng/ml.
International Nuclear Information System (INIS)
Aoki, T.; Shudo, K.; Sato, K.; Ohno, S.; Tanaka, M.
2010-01-01
Thermal structural changes of TiO x films built on a Si(0 0 1) surface were investigated at the nanometer scale with scanning tunneling microscopy. Electronic properties of individual clusters were classified by means of scanning tunneling spectroscopy. The differential conductance (dI/dV) near the Fermi energy showed that nano-clusters were transformed from semiconducting Ti-silicates into metallic Ti-silicides after heating to 970 K. Peaks of normalized differential conductance (dI/dV/(I/V)) of the clusters shifted after heating to about 1070 K, indicating exclusion of oxygen from the clusters.
New directions in scanning-tunneling microscopy
International Nuclear Information System (INIS)
Ferrell, T.L.; Warmack, R.J.; Reddick, R.C.
1989-01-01
The tunneling of electrons in scanning-tunneling microscopy (STM) has permitted imaging of the electronic distribution about individual atoms on surfaces. The need for use of conducting surfaces in STM limits its applicability, and new forms of scanning microscopy have emerged as a result of interest in poorly conducting samples. Atomic force microscopy has demonstrated that the force between a surface and a probe tip can be used to image selected materials. Now being developed are magnetic probe STM's and photon tunneling microscopes in which the probe is a sharpened optical fiber. Also of great interest presently is the measurement of differential conductance of surfaces using electron STM's. This method supplies spectral information and contrast enhancement in images. At present there remains much theoretical work to be carried out in order to better characterize related data on inelastic electron tunneling, and valuable insight may be gained from data being gathered on the local work function of materials. As matters stand today, the key problems lie in determining tip and contamination effects, preparation of samples, and understanding conductivity mechanisms in very thin materials on conducting substrates. Resolution of these problems and introduction of new forms of scanning microscopy may permit novel and important applications in biology as well as surface science
International Nuclear Information System (INIS)
Della Gatta, G.; Stradella, L.; Venturello, G.
1977-01-01
The adsorption of iodine from solution in n-pentane at 27 0 C and in cyclohexane at 35 0 C and 50 0 C on eta-Al 2 O 3 and bayerite outgassed at R.T. has been studied with a calorimetric technique. The measurements were performed by means of a Calvet type calorimeter using a new cell conceived for the adsorption from solution. The integral molar energies of adsorption show, at low coverages, a very strong interaction of iodine with surface hydroxyl groups, possibly leading to charge-transfer complexes and reactions. A peculiar exothermic effect has been also evidenced before the monolayer completion, in correspondence with a 'step' on the adsorption isotherms. This result is interpreted in terms of cooperative adsorption implying the possible formation of surface clusters around the strongly absorbed molecules. On non-porous samples (bayerite) the adsorption temperature rise decrease the total amounts adsorbed. But on porous ones (eta-Al 2 O 3 ) the adsorption is increased. (orig./HK) [de
X-ray phase scanning setup for non-destructive testing using Talbot-Lau interferometer
Bachche, S.; Nonoguchi, M.; Kato, K.; Kageyama, M.; Koike, T.; Kuribayashi, M.; Momose, A.
2016-09-01
X-ray grating interferometry has a great potential for X-ray phase imaging over conventional X-ray absorption imaging which does not provide significant contrast for weakly absorbing objects and soft biological tissues. X-ray Talbot and Talbot-Lau interferometers which are composed of transmission gratings and measure the differential X-ray phase shifts have gained popularity because they operate with polychromatic beams. In X-ray radiography, especially for nondestructive testing in industrial applications, the feasibility of continuous sample scanning is not yet completely revealed. A scanning setup is frequently advantageous when compared to a direct 2D static image acquisition in terms of field of view, exposure time, illuminating radiation, etc. This paper demonstrates an efficient scanning setup for grating-based Xray phase imaging using laboratory-based X-ray source. An apparatus consisting of an X-ray source that emits X-rays vertically, optical gratings and a photon-counting detector was used with which continuously moving objects across the field of view as that of conveyor belt system can be imaged. The imaging performance of phase scanner was tested by scanning a long continuous moving sample at a speed of 5 mm/s and absorption, differential-phase and visibility images were generated by processing non-uniform moire movie with our specially designed phase measurement algorithm. A brief discussion on the feasibility of phase scanner with scanning setup approach including X-ray phase imaging performance is reported. The successful results suggest a breakthrough for scanning objects those are moving continuously on conveyor belt system non-destructively using the scheme of X-ray phase imaging.
Energy Technology Data Exchange (ETDEWEB)
Toscani, S. [Departement de Chimie - UMR 6226, Faculte des Sciences, Universite de Rennes 1, Batiment 10B, 263 avenue du General Leclerc, F-35042 Rennes Cedex (France); Cornevin, L. [Universite de Rennes 1, Faculte de Pharmacie, 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); Burgot, G., E-mail: Gwenola.burgot@univ-rennes1.fr [Universite de Rennes 1, Faculte de Pharmacie, Laboratoire de Chimie Analytique, EA 1274 ' Mouvement, sports, sante' , 2 Avenue Leon Bernard, F-35043 Rennes Cedex (France); CHGR Rennes, Pole Medico-Technique Pharmacie, F-35703 Rennes Cedex (France)
2012-09-10
Highlights: Black-Right-Pointing-Pointer Thermodynamic and kinetic parameters of weak interactions in binary systems by DSC. Black-Right-Pointing-Pointer Energy-barrier decrease for lactose dehydration induced by clobazam. Black-Right-Pointing-Pointer Recrystallisation of metastable liquid clobazam induced by anhydrous alpha lactose. Black-Right-Pointing-Pointer Decrease of lactose dehydration temperature in binary mixtures with captopril. Black-Right-Pointing-Pointer Increase of lactose dehydration enthalpy in binary mixtures with captopril. - Abstract: The thermal behaviour of binary mixtures of two drugs (clobazam and captopril, respectively) and a pharmaceutical excipient (lactose monohydrate) was measured with differential scanning calorimetry to determine thermodynamic and kinetic parameters (dehydration and melting enthalpies and dehydration and glass-transition activation energies) which might be affected by intermolecular interactions. A kinetic study showed that lactose dehydration is not a single-step conversion and that clobazam contributed to reduce the energy barrier for the bulk dehydration of the excipient. On the other hand, the physical interactions between metastable liquid clobazam and crystalline anhydrous {alpha}-lactose obtained from monohydrate dehydration gave rise to the recrystallisation of clobazam. In the captopril-lactose system, the liquid captopril influenced the lactose dehydration: a sharp increase of the dehydration enthalpy and a concurrent reduction of the dehydration temperature were observed. Finally, it turned out that solid-phase transitions were enhanced by the contact with a liquid phase.
Refaa, Z.; Boutaous, M.; Rousset, F.; Fulchiron, R.; Zinet, M.; Xin, S.; Bourgin, P.
2014-05-01
Poly-(lactic acid) or PLA is a biodegradable polymer synthesized from renewable resources. Recently, the discovery of new polymerization routes has allowed increasing the produced volumes. As a consequence, PLA is becoming of great interest for reducing the dependence on petroleum-based plastics. Because of its interesting mechanical properties, PLA is seen as a potential substitute for some usual polymers. However, its relatively slow crystallization kinetics can be a disadvantage with regard to industrial applications. The crystallization kinetics of PLA can be enhanced by adding nucleating agents, which also influences on crystalline morphology and rheological behavior. In the present work, the isothermal quiescent crystallization kinetics of both neat PLA and PLA/talc composite (5 wt% talc) are investigated. The effects of talc on the overall crystallization kinetics and on the crystalline morphology are analyzed using both optical microscopy measurements and thermal analysis by differential scanning calorimetry.
Where is the place of bone scan in breast cancer?
International Nuclear Information System (INIS)
Nowferesti, G. H.; Ghavam Nasiri, M. R.; Anvari, K.
2002-01-01
Breast cancer is the most common female cancer in west and in Iran. The incidence in all over the world in year 2000 was 1050000 cases out of which 370000 were dead. General y bone is the most common site of distant. Metastases in beast cancer. Bone scan has an important place in the bone metastases and extent of bone disease and even in the staging and treatment protocol. In study done during 1 year, breast cancer patients and place of bone scan were studied. Every year more than 2000 new patients with cancer are diagnosed and treated in Khorasan state. And more than half of them are treated in Omid Hospital. In the year 2000 a study was done. 1336 new cases were admitted for treatment out of which 164 persons (13%) were breast cancer patients. 100 patients were selected randomly and different factors were studied. How many patients had bone scan and its place in breast cancer? Where is the most common metastatic place and relation with bone scan? The differential diagnosis in positive bone scans and comparing with radiography and patient's clinic were studied. Bone scan is positive in 35% of patients in stage III. Bone is the most common place for distant metastases in breast cancer in patients admitted in Omid hospital in year 2000. Clinical and para clinical study such as radiography and tumour markers were adjusted with bone scan, more in stages III and IV. 39 patients out of 100 studied patients had bone scan. 28 bone scan were adjusted radiologically. In 20 positive bone scan out of 28 patients with metastases 12 patients had bone metastases. Despite 5% positive bone scan in early stages can suggest that bone scan be taken for all patients with breast cancer as a basic step?
Winter, M; Winter, J; Heinzel, A; Behrendt, F F; Krohn, T; Mottaghy, F M; Verburg, F A
2015-01-01
to determine whether the first three months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy (dxWBS) in differentiated thyroid carcinoma patients. The files of 462 patients who were treated for DTC in our hospital were reviewed. All patients underwent surgical thyroidectomy. 146 patients had data available on a. a dxWBS which was performed less than four months (max 120 days) after 131I ablation with concurrent stimulated TSH stimulated thyroglobulin (Tg) measurement without further therapeutic measures between ablation and dxWBS and b. a second dxWBS or 131I therapy (rxWBS) within 1.5 years after ablation. A discordance between the initial and follow-up scan was found in 25/129 (19%) patients: of 54 patients with a positive initial dxWBS, scan results of a second dxWBS or rxWBS obtained with a suitable distance to the initial scan contradicted the initial one in 15 patients (27%). New lesions were discovered in 10/74 negative first dxWBS cases (14%). A discordance between the initial and follow-up stimulated Tg was found in 5/129 (4%) patients: 2/90 (2%) of patients with a negative stimulated Tg at initial dxWBS subsequently showed a positive results whereas 3/29 (10%) patients with an initially positive Tg showed a negative Tg level at the second procedure. Less than four months after 131I ablation is too early to perform radioiodine diagnostic whole body scintigraphy with concurrent TSH stimulated Tg measurement. The identification of the right, later, timepoint however requires further research.
Bone scans in nasopharyngeal carcinoma: local experience
International Nuclear Information System (INIS)
Tiong, S.
2004-01-01
scans (both treated), 2 had false positive bone scans (1 newly diagnosed and 1 treated), and 2 (both treated) had true negative bone scan with no increased radio-tracer uptake and no confirmed X ray imagings for metastasis.In the true positive group of patients, the radiologists were correct in their reports of consistency of bone metastasis in 3 patients and uncertain in their reports of differential causes of the increased uptake in 1 patient. In the false positive group of patients, the radiologist were correct in their reports of causes other than bone metastasis in 3 patients, incorrect in their reports of consistency of bone metastasis in 2 patients, and uncertain in their reports of differential causes of the increased uptake in 13 patients. Showing the positive bone scans are 7 patients having degenerative spine disease on Xray imagings and 3 dental diseases on clinical findings.The ages of the patients range from 18 to 88 years, with a mean age being 50.5. In the 41 patients, 35 patients had advanced stages ( Stages III and IV ) and 6 early stages ( Stages I and II). Among the patients of advanced stages, 3 having true positive and 13 false positives, whereas among the patients of early stages, 1 true positive and 1 false positive. Discussion: The results show that 44% of the patients had positive bone scans and this could be due to large number of patients (10/41)having degenerative spine diseases and dental diseases.These show that the bone scans have high sensitivity. However they do not have high specificity as only 9.8% of total or 2.2% (4/18) of the positive bone scans patients have true positives. The specificity in the treated group of patients appear to be higher being 25% (3/12 treated patients)The bone scans are therefore regarded as a screening test and if positive, they help guide and target the Xray imaging studies to confirm the bone metastasis one way or another. It is therefore useful in NPC management. The radiologists were most of the times
International Nuclear Information System (INIS)
Dantas, J.M.; Abrao, A.
1981-04-01
A contribution to the characterization of several uranium compounds obtained at the IPEN' Uranium Pilot Plant is given. Particularly, samples of ammonium diuranate (ADU) and uranium oxides were studied. The main objective was to know the stoichiometry of the ADU and the oxides resulting from its thermal transformation. ADU samples were prepared by batchwise precipitation, stationary dewatering into stove and batchwise thermal decomposition, or, alternatively, continuous precipitation, continuous filtration, continuous drying and continuous thermal decomposition inside a temperature gradient electrical furnace. All ADU were precipitated using NH 3 gas from uranul sulfate or uranyl nitrate solutions. The thermal decomposition of ADU and uranium oxides were studied in an air atmosphere by thermogravimetry (TG) and differential scanning calorimetry (DSC). Any correlation between the parameters of precipitation, drying, calcination and the hystory of the obtaintion of the several uraniumm compounds and their initial and final composition was looked for. Heating program was established to have the U 3 O 8 oxide as the final product. Intermediary phases were tentatively identified. Temperatures at which occurred the absorption water elimination, crystallization water elimination, evolution or oxidation of NH 3 , decomposition of NO -3 ion and oxygen evolution and the exo- and endothermic process for each sample were identified. (Author) [pt
Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S
2010-05-19
Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO(2))(1 - x)(ZnO)(x) (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T(g) has been determined for each glass, showing a monotonous decrease of T(g) with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T(d) very close to the respective T(g) values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T(g) in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T(g) and confirms the correlation between the BP and the MRO of glasses.
International Nuclear Information System (INIS)
Stavrou, E; Tsiantos, C; Tsopouridou, R D; Kripotou, S; Kontos, A G; Raptis, C; Capoen, B; Bouazaoui, M; Turrell, S; Khatir, S
2010-01-01
Raman scattering and differential scanning calorimetry (DSC) measurements have been carried out on four mixed tellurium-zinc oxide (TeO 2 ) 1-x (ZnO) x (x = 0.1, 0.2, 0.3, 0.4) glasses under variable temperature, with particular attention being given to the respective glass transition region. From the DSC measurements, the glass transition temperature T g has been determined for each glass, showing a monotonous decrease of T g with increasing ZnO content. The Raman study is focused on the low-frequency band of the glasses, the so-called boson peak (BP), whose frequency undergoes an abrupt decrease at a temperature T d very close to the respective T g values obtained by DSC. These results show that the BP is highly sensitive to dynamical effects over the glass transition and provides a means for an equally reliable (to DSC) determination of T g in tellurite glasses and other network glasses. The discontinuous temperature dependence of the BP frequency at the glass transition, along with the absence of such a behaviour by the high-frequency Raman bands (due to local atomic vibrations), indicates that marked changes of the medium range order (MRO) occur at T g and confirms the correlation between the BP and the MRO of glasses.
Perez Codina, Estel
2008-01-01
Moving to the high energy regime of LHC, the identification of tau leptons will become an important and very powerful tool, allowing the discovery of physics beyond the Standard Model. Many models, light SM Higgs and various SUSY models among them, predict an abundant production of taus with respect to other leptons. The ATLAS collaboration has developed tools to efficiently identify tau at trigger level, based on the advanced calorimetry and tracking capabilities. The work presented in this Master Thesis is focused on the optimization of the first trigger level energy thresholds and the second trigger level calorimetric variables. A systematic optimization is designed, which allows us to study the robustness of the trigger selection. The improvements achieved by using a sampling energy calibration are discussed. Finally, an optimization on the size of the calorimeter region used to calculate the trigger variables is performed.
International Nuclear Information System (INIS)
Bleile, A.; Egelhof, P.; Kraft, S.; Meier, H.J.; Shrivastava, A.; Weber, M.; McCammon, D.; Stahle, C.K.
2001-09-01
The accurate determination of the Lamb shift in heavy hydrogen-like ions provides a sensitive test of quantum electrodynamics in very strong Coulomb fields, not accessible otherwise. For the investigation of the Lyman-α transitions in 208 Pb 81+ or 238 U 91+ with sufficient accuracy, a high resolution calorimetric detector for hard X-rays (E ≤ 100 keV) is presently being developed. The detector modules consist of arrays of silicon thermistors and of X-ray absorbers made of high-Z material to optimize the absorption efficiency. The detectors are housed in a specially designed 3 He/ 4 He dilution refrigerator with a side arm which fits to the internal target geometry of the storage ring ESR at GSI Darmstadt. The detector performance presently achieved is already close to fulfill the demands of the Lamb shift experiment. For a prototype detector pixel with a 0.2 mm 2 x 47 μm Pb absorber an energy resolution of ΔE FWHM = 65 eV is obtained for 60 keV X-rays. (orig.)
A scan for models with realistic fermion mass patterns
International Nuclear Information System (INIS)
Bijnens, J.; Wetterich, C.
1986-03-01
We consider models which have no small Yukawa couplings unrelated to symmetry. This situation is generic in higher dimensional unification where Yukawa couplings are predicted to have strength similar to the gauge couplings. Generations have then to be differentiated by symmetry properties and the structure of fermion mass matrices is given in terms of quantum numbers alone. We scan possible symmetries leading to realistic mass matrices. (orig.)
Interaction of chloroquine and its analogues with heme: An isothermal titration calorimetric study.
Bachhawat, K; Thomas, C J; Surolia, N; Surolia, A
2000-10-05
Quinoline-containing drugs such as chloroquine and quinine have had a long and successful history in antimalarial chemotherapy. Identification of ferriprotoporphyrin IX ([Fe(III)PPIX], haematin) as the drug receptors for these antimalarials called for investigations of the binding affinity, mode of interaction, and the conditions affecting the interaction. The parameters obtained are significant in recent times with the emergence of chloroquine resistant strains of the malaria parasites. This has underlined the need to unravel the molecular mechanism of their action so as to meet the requirement of an alternative to the existing antimalarial drugs. The isothermal titration calorimetric studies on the interaction of chloroquine with haematin lead us to propose an altered mode of binding. The initial recognition is ionic in nature mediated by the propionyl group of haematin with the quaternary nitrogen on CQ. This ionic interaction induces a conformational change, such as to favour binding of subsequent CQ molecules. On the contrary, conditions emulating the cytosolic environment (pH 7.4 and 150 mM salt) reveal the hydrophobic force to be the sole contributor driving the interaction. Interaction of a carefully selected panel of quinoline antimalarial drugs with monomeric ferriprotoporphyrin IX has also been investigated at pH 5.6 mimicking the acidic environment prevalent in the food vacuoles of parasite, the center of drug activity, which are consistent with their antimalarial activity. Copyright 2000 Academic Press.
Calorimetric measurements on hafnium titanate
International Nuclear Information System (INIS)
Kandan, R.; Prabhakara Reddy, B.; Panneerselvam, G.; Nagarajan, K.
2012-01-01
Owing to its desirable nuclear and mechanical properties such as good absorption cross-section for thermal neutrons (105 barns), hafnium titanate (HfTiO 4 ) finds application as control rods for nuclear reactors. An accurate knowledge of the thermo physical properties of this material is necessary for design of control rod and for modeling its performance. Heat capacity is an important thermodynamic property that determines the temperature dependent variation of all other thermodynamic properties. Hence enthalpy increments of hafnium titanate (HfTiO 4 ) were measured in the temperature range 803-1663 K by employing the method of inverse drop calorimetry using high temperature differential calorimeter
Energy Technology Data Exchange (ETDEWEB)
Kim, Jong Hoon
1998-12-01
This study was done to evaluate the clinical feasibility of FDG-PET scan in patients with cervical carcinoma. PET-scans were performed in 74 patients with cervical carcinoma from March, 1998 to September, 1998. Fourteen cases were done at pretreatment period and sixty cases were done at post-treatment follow up period. In this study, the scans were obtained after bladder emptying by foley catheter insertion and diuretics to reduce the tracer activity in the bladder and improve the images of central lesions. We could find some incidental recurrent or metastatic lesions by FDG-PET scan (at pretreatment; 5 cases, at post-treatment; clinically no evidence of disease; 8 cases). FDG-PET scan had high sensitivity (100%) for central lesions and metastatic lymph nodes of cervical cancer but could not precisely define the anatomic location of the cancer and the sensitivity was not superior than MRI. Earlier detection of metastatic lymph nodes was superior than CT/MRI (sensitivity; 100 %) for metastatic lymph nodes. Also we found 3 double primary cancers incidentally (2 lung cancers and 1 thyroid cancer). In conclusion, FDG-FET scan might be useful for the earlier of hidden lesions that cannot be detected by routine conventional methods and differential diagnosis with radiation fibrosis and benign lymph adenophy.
Balbi, C; Abelmoschi, M L; Gogioso, L; Parodi, S; Barboro, P; Cavazza, B; Patrone, E
1989-04-18
A good deal of information on the thermodynamic properties of chromatin was derived in the last few years from optical melting experiments. The structural domains of the polynucleosomal chain, the linker, and the core particle denature as independent units. The differential scanning calorimetry profile of isolated chromatin is made up of three endotherms, at approximately 74, 90, and 107 degrees C, having an almost Gaussian shape. Previous work on this matter, however, was mainly concerned with the dependence of the transition enthalpy on external parameters, such as the ionic strength, or with the melting of nuclei from different sources. In this paper we report the structural assignment of the transitions of rat liver nuclei, observed at 58, 66, 75, 92, and 107 degrees C. They are representative of the quiescent state of the cell. The strategy adopted in this work builds on the method developed for the investigation of complex biological macromolecules. The heat absorption profile of the nucleus was related to the denaturation of isolated nuclear components; electron microscopy and electrophoretic techniques were used for their morphological and molecular characterization. The digestion of chromatin by endogenous nuclease mimics perfectly the decondensation of the higher order structure and represented the source of several misinterpretations. This point was carefully examined in order to define unambiguously the thermal profile of native nuclei. The low-temperature transitions, centered around 58 and 66 degrees C, arise from the melting of scaffolding structures and of the proteins associated with heterogeneous nuclear RNA.(ABSTRACT TRUNCATED AT 250 WORDS)
End-to-End Traffic Flow Modeling of the Integrated SCaN Network
Cheung, K.-M.; Abraham, D. S.
2012-05-01
In this article, we describe the analysis and simulation effort of the end-to-end traffic flow for the Integrated Space Communications and Navigation (SCaN) Network. Using the network traffic derived for the 30-day period of July 2018 from the Space Communications Mission Model (SCMM), we generate the wide-area network (WAN) bandwidths of the ground links for different architecture options of the Integrated SCaN Network. We also develop a new analytical scheme to model the traffic flow and buffering mechanism of a store-and-forward network. It is found that the WAN bandwidth of the Integrated SCaN Network is an important differentiator of different architecture options, as the recurring circuit costs of certain architecture options can be prohibitively high.
Preparation of LDPE/LNR Blend Via Emulsion Dispersion
International Nuclear Information System (INIS)
Rusli Daik; Yee Lee Ching
2007-01-01
Low density polyethylene (LDPE)/ liquid natural rubber (LNR) blends with the composition of 100LDPE/ 0LNR, 70LDPE/ 30LNR, 60LDPE/ 40LNR and 40LDPE/ 60LNR were prepared via dispersion of LDPE and LNR emulsion. LNR was obtained via photochemical sensitization of natural rubber (NR). Emulsion of LNR was prepared by using sodium dodecyl sulfate (SDS) and 1-hexanol as the emulsifier and co- emulsifier respectively. Emulsion of LDPE was prepared in the same way by using LDPE solution in carbon tetrachloride, SDS and 1-hexanol. LDPE/ LNR blends were prepared via mixing of LNR and LDPE emulsions. Mechanical properties of the blends were analyzed by tensile, hardness and impact test. Optimum mechanical properties were observed for composite with composition of 60LDPE/ 40LNR that showed the maximum value of stress and strain. The glass transition temperature, T g , of the blends as obtained from differential scanning calorimetric (DSC) showed that the blends were homogeneous. Morphology study by using scanning electron microscopy (SEM) also indicates the homogeneity of LDPE/ LNR blends produced. (author)
Nikolova, Kr.; Yovcheva, T.; Marudova, M.; Eftimov, T.; Bodurov, I.; Viraneva, A.; Vlaeva, I.
2016-03-01
Eleven samples from olive oil have been investigated using four physical methods - refractive index measurement, fluorescence spectra, color parameters and differential scanning colorimetry. In pomace olive oil (POO) and extra virgin olive oil (EVOO) the oleic acid (65.24 %-78.40 %) predominates over palmitic (10.47 %-15.07 %) and linoleic (5.26 %-13.92 %) acids. The fluorescence spectra contain three peaks related to oxidation products at about λ = (500-540) nm, chlorophyll content at about λ = (675-680) nm and non determined pigments at λ = (700-750) nm. The melting point for EVOO and POO is between -1 °C and -6 °C. In contrast, the salad olive oils melt between -24 °C and -30 °C. The refractive index for EVOO is lower than that for mixed olive oils. The proposed physical methods could be used for fast and simple detection of vegetable oils in EVOO without use of chemical substances. The experimental results are in accordance with those obtained by chemical analysis.
Clinical Application of Colour Modulation of Gamma Energy and Depth by Dual-Channel Scanning
Energy Technology Data Exchange (ETDEWEB)
Kaplan, E.; Ben-Porath, M. [Veterans Administration Hospital, Hines, IL (United States)
1969-01-15
A dual-channel scanning system has been described permitting the simultaneous imaging in individual color of the distribution of two gamma-emitting radioisotopes. In those cases where two organs are adjacent and concentrate the same isotope, they may be displayed in separate color if one of the organs concentrates another gamma-emitting isotope with a different energy. This is accomplished by individual color readout of this isotope and the display of the subtraction of this isotope from the common isotope in another color. By using two facing scintillation probes on either side of the individual being scanned, two overlapping organs at different depths concentrating the same isotope can be color differentiated by a dual-channel playout of each probe. The principal application of these dual-channel scanning methods to date has been the simultaneous display of the liver and pancreas in individual colors using {sup 198}Au and {sup 75}selenomethionine. Characteristic scans have been obtained which differentiate a number of disease states from the normal pancreas and liver. The pancreatic and liver diseases studied and characterized are carcinoma of the pancreas, pancreatic insufficiency, acute recurrent pancreatitis, pancreatic pseudocyst and Laennec's cirrhosis, hepatoma and metastatic malignancy in the liver. The uptake of {sup 75}selenomethionine in malignant lesions in many instances produces positive scans of these tumors in contrasting color to the liver. Depth discrimination in color with the two-probe system has permitted the lateralization of intracranial lesions, the color of the display being proportional to the depth of the lesion. The discrimination of depth and gamma-ray energy by dual-channel color scanning and its general application in visualizing other organs has been accomplished. (author)
Cryopreservation of in vitro shoot apices of Oxalis tuberosa Mol.
Gonzalez-Benito, M E; Mendoza-Condori, V H; Molina-Garcia, A D
2007-01-01
Oca (Oxalis tuberosa Mol.) is an under-utilized tuber crop from the Andean region. Cryopreservation would allow the safe and long-term preservation of the genetic resources of this crop. A protocol for the cryopreservation of in vitro grown shoots has been developed using the vitrification solution PVS2. Two genotypes were studied (G1 and G27). Nodal segments were cultured on MS medium and incubated at 10 degree C with 16 h photoperiod and 10 mol per square meter per second irradiance, for two weeks. Apices were then excised and cultured on MS+0.15 M sucrose for 3 days at 5 degree C in darkness. Subsequently, apices were immersed in a loading solution (liquid MS medium+2 M glycerol+0.4 M sucrose), and then treated with the vitrification solution PVS2 for 0 to 40 minutes. Cryovials were then immersed in liquid nitrogen. Four weeks after rewarming and culture on recovery medium, genotype G1 showed approximately 60 percent recovery (normal growth) with 20 min PVS2 treatment. Genotype G27 showed lower recovery (30 percent). Differential scanning calorimetry yielded a Tg midpoint for PSV2 solution of ca. -120 degree C. Calorimetric studies on apices at different stages of the cryopreservation protocol showed a change in calorimetric parameters consistent with a decrease in the amount of frozen water as the protocol advanced.
Energy Technology Data Exchange (ETDEWEB)
Ciulli, Alessio [University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Lobley, Carina M. C. [Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Tuck, Kellie L. [University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom); Smith, Alison G. [Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA (United Kingdom); Blundell, Tom L. [Department of Biochemistry, University of Cambridge, 80 Tennis Court Road, Cambridge CB2 1GA (United Kingdom); Abell, Chris, E-mail: ca26@cam.ac.uk [University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom)
2007-02-01
A combined crystallographic, calorimetric and mutagenic study has been used to show how changes in pH give rise to two distinct binding modes of 2′-phospho-ADP-ribose to ketopantoate reductase. The crystal structure of Escherichia coli ketopantoate reductase in complex with 2′-monophosphoadenosine 5′-diphosphoribose, a fragment of NADP{sup +} that lacks the nicotinamide ring, is reported. The ligand is bound at the enzyme active site in the opposite orientation to that observed for NADP{sup +}, with the adenine ring occupying the lipophilic nicotinamide pocket. Isothermal titration calorimetry with R31A and N98A mutants of the enzyme is used to show that the unusual ‘reversed binding mode’ observed in the crystal is triggered by changes in the protonation of binding groups at low pH. This research has important implications for fragment-based approaches to drug design, namely that the crystallization conditions and the chemical modification of ligands can have unexpected effects on the binding modes.
International Nuclear Information System (INIS)
Ciulli, Alessio; Lobley, Carina M. C.; Tuck, Kellie L.; Smith, Alison G.; Blundell, Tom L.; Abell, Chris
2007-01-01
A combined crystallographic, calorimetric and mutagenic study has been used to show how changes in pH give rise to two distinct binding modes of 2′-phospho-ADP-ribose to ketopantoate reductase. The crystal structure of Escherichia coli ketopantoate reductase in complex with 2′-monophosphoadenosine 5′-diphosphoribose, a fragment of NADP + that lacks the nicotinamide ring, is reported. The ligand is bound at the enzyme active site in the opposite orientation to that observed for NADP + , with the adenine ring occupying the lipophilic nicotinamide pocket. Isothermal titration calorimetry with R31A and N98A mutants of the enzyme is used to show that the unusual ‘reversed binding mode’ observed in the crystal is triggered by changes in the protonation of binding groups at low pH. This research has important implications for fragment-based approaches to drug design, namely that the crystallization conditions and the chemical modification of ligands can have unexpected effects on the binding modes
A functional renormalization group application to the scanning tunneling microscopy experiment
Directory of Open Access Journals (Sweden)
José Juan Ramos Cárdenas
2015-12-01
Full Text Available We present a study of a system composed of a scanning tunneling microscope (STM tip coupled to an absorbed impurity on a host surface using the functional renormalization group (FRG. We include the effect of the STM tip as a correction to the self-energy in addition to the usual contribution of the host surface in the wide band limit. We calculate the differential conductance curves at two different lateral distances from the quantum impurity and find good qualitative agreement with STM experiments where the differential conductance curves evolve from an antiresonance to a Lorentzian shape.
Han, Dong; Ma, Guangming; Wei, Lequn; Ren, Chenglong; Zhou, Jieli; Shen, Chen
2017-01-01
Objective: To investigate the value of using the quantitative parameters from only the pre-contrast dual-energy spectral CT imaging for distinguishing between parapelvic cyst and hydronephrosis with non-calculous (HNC). Methods: This retrospective study was approved by the institutional review board. 28 patients with parapelvic cyst and 24 patients with HNC who underwent standard pre-contrast and multiphase contrast-enhanced dual-energy spectral CT imaging were retrospectively identified. The parapelvic cyst and HNC were identified using the contrast-enhanced scans, and their CT number in the 70-keV monochromatic images, effective atomic number (Zeff), iodine concentration (IC) and water concentration in the pre-contrast images were measured. The slope of the spectral curve (λ) was calculated. The difference in the measurements between parapelvic cyst and HNC was statistically analyzed using SPSS® v. 19.0 (IBM Corp., New York, NY; formerly SPSS Inc., Chicago, IL) statistical software. Receiver-operating characteristic analysis was performed to assess the diagnostic performance. Results: The CT numbers in the 70-keV images, Zeff and IC values were statistically different between parapelvic cyst and HNC (all p 0.05). Conclusion: The quantitative parameters obtained in the pre-contrast dual-energy spectral CT imaging may be used to differentiate between parapelvic cyst and HNC. Advances in knowledge: The pre-contrast dual-energy spectral CT scans may be used to screen parapelvic cysts for patients who are asymptomatic, thereby avoiding contrast-enhanced CT or CT urography examination for these patients to reduce ionizing radiation dose and contrast dose. PMID:28281789
International Nuclear Information System (INIS)
Ozias, Y.
1964-10-01
The principle of this study consists in using the E. CALVET microcalorimeter for recording the energy flux emitted by radio-elements as a function of time, and in determining from this curve either their characteristics (half-life and radiation energy), or the composition of a mixture of radio-elements. In the first part the theoretical relationships describing radioactivity have been adapted to the microcalorimetric study. In the second part an experimental determination has been made using the E. CALVET microcalorimeter of the characteristics of various radio-elements, yttrium 90, phosphorus 32, sulphur 35, iodine 131, etc and of their mixtures. In particular a study has been made of the isotopic analysis of a 239 Pu - 240 Pu mixture, sometimes in the presence of 241 Pu. The microcalorimetric method is not as sensitive as conventional counting methods, its limit appears to be at the present about 1 micro-watt for the apparatus used, it is however the most direct method in the case of emitters of weakly absorbed radiation (α and β). For the γ emitters only a part of the energy is absorbed by the walls of the container. The determination of their characteristics and of their masses in the mixtures depends neither on the shape, on the dilution or even less on the auto-absorption of the source. For high activity samples this auto-absorption is the cause of great difficulties in conventional methods which complicate the operations: divisions, dissolutions, dilutions, all of which are liable to introduce errors. The calorimetric method makes it possible to work on the untreated sample. All these measurements have been carried out using the conventional E CALVET calorimeter; to carry out an exact measurement of the energy due to γ radiation, however, it is necessary to build special apparatus with a lead block the size of which is given by the author's calculations. The calorimetric method makes it possible to attain an accuracy equal to that obtained by mass
Kõiv, A; Mustonen, P; Kinnunen, P K
1994-03-31
Binding of DNA and RNA to sphingosine-containing dimyristoylphosphatidylcholine (DMPC) liposomes was characterized by differential scanning calorimetry. The thermal phase behaviour of neat DMPC liposomes was unaffected by the presence of the nucleic acids. However, significant alterations in the melting profiles of the DMPC/sphingosine composite membranes were produced by DNA and RNA, thus revealing their binding to the liposomes. For example, for 79:21 (molar ratio) DMPC/sphingosine liposomes a single endotherm at 29.1 degrees C with an enthalpy of 6.3 kcal/mol lipid was observed. In the presence of DNA at the nucleotide/sphingosine ratio of 0.6 this endotherm separated into three distinct peaks at 28.0, 31.4 and 35.1 degrees C, together with an approximately 22% reduction in the total enthalpy. Further increase in DNA concentration up to 1.5 nucleotides per sphingosine led to complete loss of the original heat absorption peak of the DMPC/sphingosine liposomes, while an endotherm at 34.3 degrees C with delta H of 2.7 kcal/mol developed. By visual inspection, rapid and extensive aggregation of the liposomes due to DNA was evident. Evidence for DNA-induced phase separation was also provided by compression isotherms of sphingosine containing DMPC monolayers recorded over an aqueous buffer both in the presence and absence of DNA. The effects of RNA on the thermal phase behaviour of the composite liposomes were qualitatively similar to those described above for DNA. Notably, the presence of eggPA abolished the nucleic acid induced heat capacity changes for DMPC/sphingosine liposomes probably because of neutralization of the positive charge of sphingosine. The binding of DNA to DMPC/sphingosine liposomes occurred both below and above the lipid phase transition temperature, as shown by fluorescence resonance energy transfer utilizing adriamycin-labelled DNA as a quencher and membrane incorporated pyrene-labelled phospholipid as a donor. However, the apparent binding to
Energy Technology Data Exchange (ETDEWEB)
Mentzel, Hans-Joachim; Malich, Ansgar; Freesmeyer, Martin; Boettcher, Joachim; Vogt, Susanna; Kaiser, Werner A. [Institute of Diagnostic and Interventional Radiology, University of Jena, Bachstrasse 18, 07740 Jena (Germany); Kentouche, Karim; Gruhn, Bernd; Zintl, Felix [Department of Pediatrics, University of Jena, Jena (Germany); Schneider, Gerlind [Department of Otorhinolaryngology, University of Jena, Jena (Germany); Anderson, Roselle [Siemens-Elema, Elema (Sweden)
2003-07-01
Precise assessment of lymph nodes is crucial to the choice of therapy and prediction of outcome in cases of malignancy. Electrical impedance scanning (EIS) is being experimentally investigated for potential use as a diagnostic tool for differentiation of malignant lesions. Malignancies show different electrical properties with changes in conductivity and capacitance that can be analysed by EIS. Using a TransScan TS-2000 (TransScan Medical, Migdal Ha'Emek, Israel, distributed by Siemens-Elema AB, Solna, Sweden), EIS has been used in various studies for the identification of breast cancer as well as for characterisation of superficial lesions. To evaluate the reliability of EIS for classifying lymph nodes in a pediatric population with sonographically suspicious lesions and to prove its accuracy. The study population consisted of 77 children (42 boys, 35 girls) aged 1.1-17.1 years. All EIS results were compared to either histopathological findings or long-term follow-up investigations. Sensitivity for malignancies using EIS was 75% and specificity was 87%. The negative predictive value was 93% and the positive predictive value was 60%. This study suggests the potential usefulness of EIS as an additional imaging modality for the differentiation of lymph-node diseases in children. The histopatholgical spectrum of malignant lymph node transformation in children compared to studies in adults, and the characteristic meltdown in inflammatory or granulomatous transformed nodes, pose challenges to differentiation based on sonographic evaluation, and also to EIS classification. (orig.)
International Nuclear Information System (INIS)
Arii, T.; Kishi, A.
1999-01-01
The thermal dehydration study of the similar hydrated salts, cobalt and zinc formate dihydrates, have been carried out successfully by means of X-ray diffractometry-differential scanning calorimetry (XRD-DSC) and controlled-rate thermogravimetry (CRTG). X-ray diffraction analysis recorded simultaneously indicates that the resulting anhydrous product, Zn(HCO 2 ) 2 , was crystalline, while Co(HCO 2 ) 2 was amorphous.The XRD-DSC data are proven to be invaluable in verifying the interpretation of overlapping processes in thermal events. In addition, these differences in the resulting anhydrous products can be explained from kinetic analysis results based on the CRTG data. The kinetic mechanism governing the dehydration of zinc formate dihydrate is a nucleation and growth process, while in the case of cobalt formate dihydrate a phase boundary controlled reaction is the governing mechanism. (Copyright (c) 1999 Elsevier Science B.V., Amsterdam. All rights reserved.)
International Nuclear Information System (INIS)
Jeong, Hwan Jeong; Lim, Seok Tae; Youn, Hyun Jo; Sohn, Myung-Hee
2008-01-01
Recently, a number of patients needed total thyroidectomy and high dose radioiodine therapy (HD-RAI) get increased more. The aim of this study is to evaluate whether pathological staging (PS) and serum thyroglobulin (sTG) level could replace the diagnostic I-123 scan for the determination of therapeutic dose of HD-RAI in patients with differentiated thyroid cancer. Fifty eight patients (M:F=13;45, age 44.5±11.5 yrs) who underwent total thyroidectomy and central or regional lymph node dissection due to differentiated thyroid cancer were enrolled. Diagnostic scan of I-123 and sTG assay were also performed on off state of thyroid hormone. The therapeutic doses of I-131 (TD) were determined by the extent of uptakes on diagnostic I-123 scan as a gold standard. PS was graded by the criteria recommended in 6th edition of AJCC cancer staging manual except consideration of age. For comparison of the determination of therapeutic doses, PS and sTG were compared with the results of I-123 scan. All patients were underwent HD-RAI. Among them, five patients (8.6%) were treated with 100 mCi of I-131, forty three (74.1%) with 150 mCi, six (10.3%) with 180 mCi, three (5.2%) with 200 mCi, and one (1.7%) with 250 mCi, respectively. On the assessment of PS, average TDs were 154±25 mCi in stage I (n=9), 175±50 mCi in stage II (n=4), 149±21 mCi in stage III (n=38), and 161±20 mCi in stage IV (n=7). The statistical significance was not shown between PS and TD (p=0.169). Among fifty two patients who had available sTG, 25 patients (48.1%) having below 2 ng/mL of sTG were treated with 149±26 mCi of I-131, 9 patients (17.3%) having 2≤ sTG <5 ng/mL with 156±17 mCi, 5 patients (9.6%) having 5≤ sTG <10 ng/mL with 156±13 mCi, 7 patients (13.5%) having 10≤ sTG <50 ng/mL with 147±24 mCi, and 6 patients (11.5%) having above 50 ng/mL with 175±42 mCi. The statistical significance between sTG level and TD (p=0.252) was not shown. In conclusion, PS and sTG could not replace the
Calorimetric analysis of heating and cooling process of nodular cast iron
Directory of Open Access Journals (Sweden)
Bińczyk F.
2007-01-01
Full Text Available The study presents the results of investigations of the thermal effects which take place during heating and cooling of samples of the nodular graphite cast iron taken from the stepped test casting of the wall thicknesses amounting to 5, 10, 15 and 20 mm. For investigations, a differential scanning calorimeter, type Multi HTC S60, was used. During heating, three endothermic effects related with pearlite decomposition, phase transformation α → γ, and carbon dissolution in austenite were observed on a DSC diagram. During cooling, two exothermic effects related with phase transformation γ→ α and pearlite formation were observed to consecutively take place on a DSC diagram. The values of the enthalpy of these processes differ and depend on the initial microstructure of the examined samples. The metallic matrix in 5 mm sample after the process of heating and cooling changes totally in favour of ferrite. The same effect, though less advanced in intensity, takes place in 10 mm sample, while in 15 and 20 mm samples the matrix constitution remains unchanged. The higher is the content of ferrite in samples, the stronger is the endothermic effect of the α → γ transformation and the weaker is the endothermic effect related with carbon dissolution in austenite. The total of the endothermic effects (heating is reduced, while that of the exothermic effects (cooling increases along with the increasing thickness of walls in a stepped test casting, from which samples for the investigations were taken.
Directory of Open Access Journals (Sweden)
Aihong eYang
2016-05-01
Full Text Available Understanding adaptive genetic variation and its relation to environmental factors are important for understanding how plants adapt to climate change and for managing genetic resources. Genome scans for the loci exhibiting either notably high or low levels of population differentiation (outlier loci provide one means of identifying genomic regions possibly associated with convergent or divergent selection. In this study, we combined AFLP genome scan and environmental association analysis to test for signals of natural selection in natural populations of Liriodendron chinense (Chinese Tulip Tree; Magnoliaceae along a latitudinal transect. We genotyped 276 individuals from 11 populations of L. chinense using 987 AFLP markers. Two complementary methods (Dfdist and BayeScan and association analysis between AFLP loci and climate factors were applied to detect outlier loci. Our analyses recovered both neutral and potentially adaptive genetic differentiation among populations of L. chinense. We found moderate genetic diversity within populations and high genetic differentiation among populations with reduced genetic diversity towards the periphery of the species ranges. Nine AFLP marker loci showed evidence of being outliers for population differentiation for both detection methods. Of these, six were strongly associated with at least one climate factor. Temperature, precipitation and radiation were found to be three important factors influencing local adaptation of L. chinense. The outlier AFLP loci are likely not the target of natural selection, but the neighboring genes of these loci might be involved in local adaptation. Hence, these candidates should be validated by further studies.
International Nuclear Information System (INIS)
Morris, A.; Lipe, T.
1996-01-01
In a previous article Van Humbeeck and Planes have made a number of criticisms of the authors' recent paper concerning the interpretation of the results obtained by Differential Scanning Calorimetry (DSC) from the Martensitic Transformation of Cu-Al-Ni-Mn-B alloys. Although the martensitic transformation of these shape memory alloys is generally classified as athermal, it has been confirmed that the capacity of the alloys to undergo a more complete thermoelastic transformation (i.e. better reversibility of the transformation) increased with the Mn content. This behavior has been explained by interpreting the DSC results obtained during thermal cycling in terms of a thermally activated mechanism controlling the direct and reverse transformations. When the heating rate increases during the reverse transformation the DSC curves shift towards higher temperatures while they shift towards the lower temperatures when the cooling rate was increased during the direct transformation. Since the starting transformation temperatures (As, Ms) do not shift, Van Humbeeck and Planes state that there is no real peak shift and assume that the DCS experiments were carried out without taking into account the thermal lag effect between sample and cell. On the following line they deduce a time constant, τ, of 60 seconds because the peak maximum shifts. In fact the assumption made by Van Humbeeck and Planes is false
International Nuclear Information System (INIS)
Rai, Arun Kumar; Raju, S.; Jeyaganesh, B.; Mohandas, E.; Sudha, R.; Ganesan, V.
2009-01-01
The kinetic aspects of allotropic phase changes in uranium are studied as a function of heating/cooling rate in the range 10 0 -10 2 K min -1 by isochronal differential scanning calorimetry. The transformation arrest temperatures revealed a remarkable degree of sensitivity to variations of heating and cooling rate, and this is especially more so for the transformation finish (T f ) temperatures. The results obtained for the α → β and β → γ transformations during heating confirm to the standard Kolmogorov-Johnson-Mehl-Avrami (KJMA) model for a nucleation and growth mediated process. The apparent activation energy Q eff for the overall transformation showed a mild increase with increasing heating rate. In fact, the heating rate normalised Arrhenius rate constant, k/β reveals a smooth power law decay with increasing heating rate (β). For the α → β phase change, the observed DSC peak profile for slower heating rates contained a distinct shoulder like feature, which however is absent in the corresponding profiles found for higher heating rates. The kinetics of γ → β phase change on the other hand, is best described by the two-parameter Koistinen-Marburger empirical relation for the martensitic transformation
Pajzderska, Aleksandra; Chudoba, Dorota M; Mielcarek, Jadwiga; Wąsicki, Jan
2012-10-01
Two forms of sibutramine hydrochloride, monohydrate and anhydrous, have been investigated by calorimetric methods, Fourier transform infrared (FTIR) absorption and (1) H nuclear magnetic resonance (NMR) measurements as well as by density functional theory (DFT) of vibrational frequencies and infrared intensities, calculations of steric hindrances and Monte Carlo simulations. The results of FTIR spectra combined with DFT calculations permitted identification of the bands corresponding to the dynamics and vibrations of water molecules. NMR study and Monte Carlo simulations revealed the occurrence of reorientation jumps of the methyl groups in sibutramine cation and also revealed that the reorientation of isopropyl group is possible only in sibutramine monohydrate hydrochloride. The hydration of sibutramine hydrochloride causes a change in the conformation of sibutramine cation. Copyright © 2012 Wiley-Liss, Inc.
Technical considerations on scanning and image analysis for amyloid PET in dementia
International Nuclear Information System (INIS)
Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Senda, Michio; Yamamoto, Yasuji
2017-01-01
Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice. (author)
Technical Considerations on Scanning and Image Analysis for Amyloid PET in Dementia.
Akamatsu, Go; Ohnishi, Akihito; Aita, Kazuki; Ikari, Yasuhiko; Yamamoto, Yasuji; Senda, Michio
2017-01-01
Brain imaging techniques, such as computed tomography (CT), magnetic resonance imaging (MRI), single photon emission computed tomography (SPECT), and positron emission tomography (PET), can provide essential and objective information for the early and differential diagnosis of dementia. Amyloid PET is especially useful to evaluate the amyloid-β pathological process as a biomarker of Alzheimer's disease. This article reviews critical points about technical considerations on the scanning and image analysis methods for amyloid PET. Each amyloid PET agent has its own proper administration instructions and recommended uptake time, scan duration, and the method of image display and interpretation. In addition, we have introduced general scanning information, including subject positioning, reconstruction parameters, and quantitative and statistical image analysis. We believe that this article could make amyloid PET a more reliable tool in clinical study and practice.
Evaluation of supine and sitting cardiac blood pool scans with sup(99m)Tc-HSA
International Nuclear Information System (INIS)
Bunko, Hisashi; Kuwajima, Akira; Hisada, Kinichi
1977-01-01
In the differential diagnosis of enlarged cardiac silhouette on plain chest x-ray film, cardiac blood pool scan was usually performed at first. However, small amount of pericardial effusion was difficult to detect on cardiac blood pool scan and differentiation of pericardial effusion from myocardial thickening was sometimes difficult. We evaluated cardiac blood pool scan with sup(99m)Tc-HSA(human serum albumin) and gamma camera imaged on both supine and sitting position, and evaluated diagnostic efficiency of criteria for pericardial effusion of these scans. Fifty-seven patients suspected of having pericardial effusion were included in the study. Sixteen of these patients had pericardial effusion and 2 of these 16 patients had free pleural effusion. Three patients had pleural effusion alone and excluded from the study. Of the five criteria for pericardial effusion, separation between heart and right lung activities was most frequent in both effusion (true positive, TP=100% on both supine and sitting) and no effusion (false positive, FP=18.4% on supine and 23.7% on sitting) groups. However, increased heart and right lung separation on sitting position was rather frequent in effusion group, and this finding was also thought to be typical for effusion but not for myocardial thickening. Decreased cardiohepatic separation on sitting position was frequent in no effusion group, and FP rate was decreased from 18.4% (supine) to 10.5% (sitting). Two patients with both pericardial effusion and free pleural effusion were easily diagnosed on sitting cardiac blood pool scan. With ROC(receiver operating characteristic) curve, three criteria should be agreed on either supine or sitting scan for diagnosis of pericardial effusion, and six criteria should be agreed when both supine and sitting scans were employed for diagnosis of pericardial effusion. (auth.)
Diagnostic evaluation of the adrenal scanning using 131I-adosterol
International Nuclear Information System (INIS)
Sugawara, Seiya; Nakamura, Mamoru; Sawai, Yoshikazu; Fukuchi, Soitsu.
1978-01-01
We have performed adrenal scanning in the 30 patients with suspected adrenal disorders eight days after the intravenous administration of about 500 μCi of 131 I-adosterol (NCL-6- 131 I), using 5 inch crystal rectilinear scintiscanner. Successful image of the adrenals was obtained in all the patients. In the 30 patients, 27 were proved to have adrenal disorders by surgical and hormonal findings. In 13 patients with primary aldosteronism, the side of adrenal adenoma was diagnosed correctly in all the cases by adrenal scanning. We could detected a small aldosterone-producing adenoma which measured 11 x 8 x 6 mm in size. In two patients with idiopathic hyperaldosteronism, asymmetrical radio-uptake between the two adrenals was seen on the standard scanning, and it was difficult to differentiate between tumor or hyperplasia. Dexamethazone-modified suppression scanning was very effective in lateralizing adenomas in the patients with primary aldosteronism. Two patients with Cushing's syndrome due to adrenal hyperplasia showed prominent and almost equal radioactivity of both the adrenal glands. Adrenal adenomas in 8 patients with Cushing's syndrome were definitely visualized on adrenal scanning, with no uptake in the contralateral sides. In one patient with Cushing's syndrome due to an adrenal carcinoma, adrenal scanning showed significant activity in the area of the carcinoma, and no uptake on the opposite side. In one patient with adrenogenital syndrome due to a virilizing adenoma with focal malignancy, adrenal scanning showed high radioactivity in the region of the tumor, and moderate activity on the opposite side. Also in the case of adrenal carcinoma, we appreciated diagnostic value of the adrenal scanning utilizing 131 I-adosterol. (author)
Evaluation of /sup 201/TlCl and delayed scan for thyroid imaging agent
Energy Technology Data Exchange (ETDEWEB)
Taniguchi, Tatsuyoshi; Harada, Taneichi; Takahashi, Tatsuo; Senoo, Tsuneaki; Ohtsuka, Nobuaki; Ito, Yasuhiko [Kawasaki Medical School, Kurashiki, Okayama (Japan)
1982-11-01
The results of 189 patients with nodular goiter by imaging with /sup 201/TlCl following with sup(99m)TcO/sub 4//sup -/ was presented. Accumulation of /sup 201/TlCl to the corresponding area was observed in 85.5% of cancer, 62.2% of adenoma, 42.5% of adenomatous goiter, and the usefulness of /sup 201/TlCl (early scan) for thyroid imaging agent was recognized. On the other hand, delayed scan for purpose of differentiation from benign to malignant was also performed. However, no significant differences were obtained.
International Nuclear Information System (INIS)
Sudharsana, N.; Krishnakumar, V.; Nagalakshmi, R.
2015-01-01
Graphical abstract: ORTEP diagram of HQDBT. - Highlights: • Single crystal XRD and NMR studies confirm the formation of the title compound. • SHG efficiency was found to be 0.6 times that of KDP. • First-order hyperpolarizability (β) was calculated using HF and B3LYP methods. - Abstract: A novel 8-hydroxyquinolinium dibenzoyl-(L)-tartrate methanol monohydrate crystal has been grown by slow evaporation technique. The single crystal X-ray diffraction analysis has been done for the title compound and is found to crystallize in orthorhombic space group P2 1 2 1 2 1 . The optical absorption cut-off wavelength is found to be 440 nm. The vibrational analysis has been carried out to assess the functional groups present in the title compound. The molecular structure of the title compound has been confirmed by nuclear magnetic resonance spectroscopy. Thermogravimetric, differential scanning calorimetric and differential thermal analyses reveal the melting point and thermal stability of the title compound. The second harmonic generation efficiency is confirmed by Kurtz–Perry powder technique. Further quantum chemical calculations are performed using Gaussian 03 software
Uninformative polymorphisms bias genome scans for signatures of selection
Directory of Open Access Journals (Sweden)
Roesti Marius
2012-06-01
Full Text Available Abstract Background With the establishment of high-throughput sequencing technologies and new methods for rapid and extensive single nucleotide (SNP discovery, marker-based genome scans in search of signatures of divergent selection between populations occupying ecologically distinct environments are becoming increasingly popular. Methods and Results On the basis of genome-wide SNP marker data generated by RAD sequencing of lake and stream stickleback populations, we show that the outcome of such studies can be systematically biased if markers with a low minor allele frequency are included in the analysis. The reason is that these ‘uninformative’ polymorphisms lack the adequate potential to capture signatures of drift and hitchhiking, the focal processes in ecological genome scans. Bias associated with uninformative polymorphisms is not eliminated by just avoiding technical artifacts in the data (PCR and sequencing errors, as a high proportion of SNPs with a low minor allele frequency is a general biological feature of natural populations. Conclusions We suggest that uninformative markers should be excluded from genome scans based on empirical criteria derived from careful inspection of the data, and that these criteria should be reported explicitly. Together, this should increase the quality and comparability of genome scans, and hence promote our understanding of the processes driving genomic differentiation.
Digital differential confocal microscopy based on spatial shift transformation.
Liu, J; Wang, Y; Liu, C; Wilson, T; Wang, H; Tan, J
2014-11-01
Differential confocal microscopy is a particularly powerful surface profilometry technique in industrial metrology due to its high axial sensitivity and insensitivity to noise. However, the practical implementation of the technique requires the accurate positioning of point detectors in three-dimensions. We describe a simple alternative based on spatial transformation of a through-focus series of images obtained from a homemade beam scanning confocal microscope. This digital differential confocal microscopy approach is described and compared with the traditional Differential confocal microscopy approach. The ease of use of the digital differential confocal microscopy system is illustrated by performing measurements on a 3D standard specimen. © 2014 The Authors Journal of Microscopy © 2014 Royal Microscopical Society.
CONSUMER PREFERENCES FOR SCANNING MODALITY TO DIAGNOSE FOCAL LIVER LESIONS.
Whitty, Jennifer; Filby, Alexandra; Smith, Adam B; Carr, Louise M
2015-01-01
Differences in the process of using liver imaging technologies might be important to patients. This study aimed to investigate preferences for scanning modalities used in diagnosing focal liver lesions. A discrete choice experiment was administered to 504 adults aged 25 ≥years. Respondents made repeated choices between two hypothetical scans, described according to waiting time for scan and results, procedure type, the chance of minor side-effects, and whether further scanning procedures were likely to be required. Choice data were analyzed using mixed-logit models with respondent characteristics used to explain preference heterogeneity. Respondents preferred shorter waiting times, the procedure to be undertaken with a handheld scanner on a couch instead of within a body scanner, no side-effects, and no follow–up scans (p≤.01). The average respondent was willing to wait an additional 2 weeks for the scan if it resulted in avoiding side-effects, 1.5 weeks to avoid further procedures or to be told the results immediately, and 1 week to have the scan performed on a couch with a handheld scanner. However, substantial heterogeneity was observed in the strength of preference for desirable imaging characteristics. An average individual belonging to a general population sub–group most likely to require imaging to characterize focal liver lesions in the United Kingdom would prefer contrast–enhanced ultrasound over magnetic resonance imaging or computed tomography. Insights into the patient perspective around differential characteristics of imaging modalities have the potential to be used to guide recommendations around the use of these technologie
An interchangeable scanning Hall probe/scanning SQUID microscope
International Nuclear Information System (INIS)
Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin; Chen, Tse-Jun; Wang, M. J.; Ling, D. C.; Chi, C. C.; Chen, Jeng-Chung
2014-01-01
We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10 −7 T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La 2/3 Ca 1/3 MnO 3 thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K
Is TrichoScan a new diagnostic method for diffuse hair loss?
Uce Özkol, Hatice; Çalka, Ömer; Akdeniz, Necmettin
2014-01-01
In this study, we investigated the sensitivity of TrichoScan, a computer-based phototrichogram, in the evaluation of diffuse hair loss in women and the relationship between iron deficiency anemia and hair loss. We recruited 100 female patients with diffuse hair loss. In all of the patients, a 1-cm2 area of hair located in a temporoparietal region was shortened to 0.5 mm. The shaved scalp regions were stained with black dye. The subject then waited for 12 min. Subsequently, pictures of these regions were taken with a videodermoscope and analyzed with the TrichoScan software program. The ferritin levels were markedly low in these groups. The ratio of anagen was highest in the telogen effluvium (TE) mild group, followed by the TE severe group, and was lowest in the androgenetic alopecia (AGA) group (P hair analysis results with the TrichoScan software were satisfactory and the results were consistent with the clinical diagnosis. In particular, the use of TrichoScan was very successful in the differentiation between AGA and TE.
The Usefulness of Bone Scan in Electric Burns
International Nuclear Information System (INIS)
Kim, Tae Hyung; So, Yong Seon; Kweon, Ki Hyeon; Han, Sang Woong; Kim, Seok Hwan; Kim, Jong Soon; Han, Seung Soo
1996-01-01
Bone scan is known to be an effective tool for observing the state of soft tissues and bones of electric burn patients. It is also used for observing the progress of patients after debridement or skin graft as well as determining to amputate specific body parts. To evaluate bone scan's role in electric burn, we analyzed bone scan 37 patients with electric burn. Among the 37 patients, 8 of 37 were injured in low voltage and 29 of them in high voltage. 27 patients received the electrical input through the hand, 6 through the scalp, 2 through the shoulder, 1 through the left chest wall and 1 through the left inguinal area. Among 29 patients received high voltage, 22 patients had the electrical output through the foot, 3 through the hand, 2 through the shoulder, 1 through the buttock and 1 through the left chest wall. Bone scans revealed cellulitis in 37 patients with 47 sites, osteomyelitis in 15 patients with 15 sites and bone defects in 4 patients with 4 sites. In 4 patients with skin graft or skin flap, follow up bone scan showed improvements of bony uptake in preoperatively bony defect area and all of them were healed without complication There were 2 cases in which uptake increased in the myocardium, 1 in the liver and 6 in the kidney, however, scrum calcium level, EKG, cardiac enzyme, liver and renal function tests were normal. In conclusion, bone scans are helpful in the assessment of injury sites after electrical insult and in differential diagnosis of cellulitis and osteomyelitis. It is also useful tool of assessment after skin graft or skin flap, however, it should be further evaluated about internal organ damage.
The Usefulness of Bone Scan in Electric Burns
Energy Technology Data Exchange (ETDEWEB)
Kim, Tae Hyung; So, Yong Seon; Kweon, Ki Hyeon; Han, Sang Woong; Kim, Seok Hwan; Kim, Jong Soon; Han, Seung Soo [Hanil Hospital, Seoul (Korea, Republic of)
1996-03-15
Bone scan is known to be an effective tool for observing the state of soft tissues and bones of electric burn patients. It is also used for observing the progress of patients after debridement or skin graft as well as determining to amputate specific body parts. To evaluate bone scan's role in electric burn, we analyzed bone scan 37 patients with electric burn. Among the 37 patients, 8 of 37 were injured in low voltage and 29 of them in high voltage. 27 patients received the electrical input through the hand, 6 through the scalp, 2 through the shoulder, 1 through the left chest wall and 1 through the left inguinal area. Among 29 patients received high voltage, 22 patients had the electrical output through the foot, 3 through the hand, 2 through the shoulder, 1 through the buttock and 1 through the left chest wall. Bone scans revealed cellulitis in 37 patients with 47 sites, osteomyelitis in 15 patients with 15 sites and bone defects in 4 patients with 4 sites. In 4 patients with skin graft or skin flap, follow up bone scan showed improvements of bony uptake in preoperatively bony defect area and all of them were healed without complication There were 2 cases in which uptake increased in the myocardium, 1 in the liver and 6 in the kidney, however, scrum calcium level, EKG, cardiac enzyme, liver and renal function tests were normal. In conclusion, bone scans are helpful in the assessment of injury sites after electrical insult and in differential diagnosis of cellulitis and osteomyelitis. It is also useful tool of assessment after skin graft or skin flap, however, it should be further evaluated about internal organ damage.
Energy Technology Data Exchange (ETDEWEB)
Adriani, O. [University of Florence, IFAC (CNR) and INFN (Italy); Akaike, Y. [ICRR, University of Tokyo (Japan); Asaoka, Y. [Waseda University (Japan); Asano, K. [Tokyo Institute of Technology (Japan); Bagliesi, M.G.; Bigongiari, G. [University of Siena and INFN (Italy); Binns, W.R. [Washington University-St. Louis (United States); Bongi, M. [University of Florence, IFAC (CNR) and INFN (Italy); Buckley, J.H. [Washington University-St. Louis (United States); Cassese, A.; Castellini, G. [University of Florence, IFAC (CNR) and INFN (Italy); Cherry, M.L. [Louisiana State University (United States); Collazuol, G. [University of Padova and INFN (Italy); Ebisawa, K. [JAXA/ISAS (Japan); Di Felice, V. [University of Rome Tor Vergata and INFN (Italy); Fuke, H. [JAXA/ISAS (Japan); Guzik, T.G. [Louisiana State University (United States); Hams, T. [CRESST/NASA/GSFC and University of Maryland (United States); Hasebe, N. [Waseda University (Japan); Hareyama, M. [St. Marianna University School of Medicine (Japan); and others
2014-11-15
The CALorimetric Electron Telescope (CALET) space experiment, currently under development by Japan in collaboration with Italy and the United States, will measure the flux of cosmic-ray electrons (including positrons) to 20 TeV, gamma rays to 10 TeV and nuclei with Z=1 to 40 up to 1,000 TeV during a two-year mission on the International Space Station (ISS), extendable to five years. These measurements are essential to search for dark matter signatures, investigate the mechanism of cosmic-ray acceleration and propagation in the Galaxy and discover possible astrophysical sources of high-energy electrons nearby the Earth. The instrument consists of two layers of segmented plastic scintillators for the cosmic-ray charge identification (CHD), a 3 radiation length thick tungsten-scintillating fiber imaging calorimeter (IMC) and a 27 radiation length thick lead-tungstate calorimeter (TASC). CALET has sufficient depth, imaging capabilities and excellent energy resolution to allow for a clear separation between hadrons and electrons and between charged particles and gamma rays. The instrument will be launched to the ISS within 2014 Japanese Fiscal Year (by the end of March 2015) and installed on the Japanese Experiment Module-Exposed Facility (JEM-EF). In this paper, we will review the status and main science goals of the mission and describe the instrument configuration and performance.
Cure Kinetics of Benzoxazine/Cycloaliphatic Epoxy Resin by Differential Scanning Calorimetry
Gouni, Sreeja Reddy
Understanding the curing kinetics of a thermoset resin has a significant importance in developing and optimizing curing cycles in various industrial manufacturing processes. This can assist in improving the quality of final product and minimizing the manufacturing-associated costs. One approach towards developing such an understanding is to formulate kinetic models that can be used to optimize curing time and temperature to reach a full cure state or to determine time to apply pressure in an autoclave process. Various phenomenological reaction models have been used in the literature to successfully predict the kinetic behavior of a thermoset system. The current research work was designed to investigate the cure kinetics of Bisphenol-A based Benzoxazine (BZ-a) and Cycloaliphatic epoxy resin (CER) system under isothermal and nonisothermal conditions by Differential Scanning Calorimetry (DSC). The cure characteristics of BZ-a/CER copolymer systems with 75/25 wt% and 50/50 wt% have been studied and compared to that of pure benzoxazine under nonisothermal conditions. The DSC thermograms exhibited by these BZ-a/CER copolymer systems showed a single exothermic peak, indicating that the reactions between benzoxazine-benzoxazine monomers and benzoxazine-cycloaliphatic epoxy resin were interactive and occurred simultaneously. The Kissinger method and isoconversional methods including Ozawa-Flynn-Wall and Freidman were employed to obtain the activation energy values and determine the nature of the reaction. The cure behavior and the kinetic parameters were determined by adopting a single step autocatalytic model based on Kamal and Sourour phenomenological reaction model. The model was found to suitably describe the cure kinetics of copolymer system prior to the diffusion-control reaction. Analyzing and understanding the thermoset resin system under isothermal conditions is also important since it is the most common practice in the industry. The BZ-a/CER copolymer system with
The effects of viscoelastic polymer substrates on adult stem cell differentiation
Chang, Chungchueh; Fields, Adam; Ramek, Alex; Jurukovski, Vladimir; Simon, Marcia; Rafailovich, Miriam
2009-03-01
Dental Pulp Stem Cells (DPSCs) are known to differentiate in either bone, dentine, or nerve tissue by different environment signals. In this study, we have determined whether differentiation could only through modification of the substrate mechanics. Atomic Force Microscopy (AFM) on Shear Modulation Force Microscopy (SMFM) mode indicated that the spun-cast polybutadiene (PB) thin films could be used to provide different stiffness substrates by changing the thicknesses of thin films. DPSCs were then plated on these substrates and cultured in standard media. After 28 days incubation, Lasar Scanning Confocal Microscopy (LSCM) with mercury lamp indicated that the crystals were observed only on hard surfaces. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray analysis (EDX analysis) indicated that the crystals are calcium phosphates. The Glancing Incidence Diffraction (GID) was also used to determine the structure of crystals. These results indicate that DPSCs could be differentiated into osteoblasts by mechanical stimuli from substrate mechanics.
Directory of Open Access Journals (Sweden)
Adriani O.
2015-01-01
Full Text Available The CALorimetric Electron Telescope (CALET is a space experiment, currently under development by Japan in collaboration with Italy and the United States, which will measure the flux of cosmic-ray electrons (and positrons up to 20 TeV energy, of gamma rays up to 10 TeV, of nuclei with Z from 1 to 40 up to 1 PeV energy, and will detect gamma-ray bursts in the 7 keV to 20 MeV energy range during a 5 year mission. These measurements are essential to investigate possible nearby astrophysical sources of high energy electrons, study the details of galactic particle propagation and search for dark matter signatures. The main detector of CALET, the Calorimeter, consists of a module to identify the particle charge, followed by a thin imaging calorimeter (3 radiation lengths with tungsten plates interleaving scintillating fibre planes, and a thick energy measuring calorimeter (27 radiation lengths composed of lead tungstate logs. The Calorimeter has the depth, imaging capabilities and energy resolution necessary for excellent separation between hadrons, electrons and gamma rays. The instrument is currently being prepared for launch (expected in 2015 to the International Space Station ISS, for installation on the Japanese Experiment Module - Exposure Facility (JEM-EF.
First calorimetric determination of heat of extraction of 248Cm in a bi-phasic system
International Nuclear Information System (INIS)
Martin, Leigh R.; Zalupski, Peter R.
2011-01-01
This report presents a summary of the work performed to meet FCR and D level 2 milestone M21SW050201, 'Complete the first calorimetric determination of heat of extraction of 248Cm in a bi-phasic system'. This work was carried out under the auspices of the Thermodynamics and Kinetics FCR and D work package. To complement previous work undertaken under this work package we have extended out heat of extraction studies by di-2-ethyl-hexyl-phosphoric acid to curium. This report also details the heat of extraction of samarium in the same system. This work was performed to not only test the methodology but also to check for consistency with the heats of extraction obtained with those in the prior literature. The heat of extraction for samarium that was obtained in this study was -9.6 kJ mol-1, which is in reasonable agreement with the previously obtained value of -10.9 kJ mol-1. The curium heat of extraction was performed under two sets of conditions and the obtained heats of extraction were in reasonable agreement with each other at -16.0 ± 1.1 and -16.8 ± 1.5 kJ mol-1.
Evaluation of inductive heating energy of sub-size improved DPC-C conductor by calorimetric method
International Nuclear Information System (INIS)
Ito, Toshinobu; Koizumi, Norikiyo; Wakabayashi, Hiroshi; Miura, Yuushi; Fujisaki, Hiroshi; Matsui, Kunihiro; Takahashi, Yoshikazu; Tsuji, Hiroshi
1996-08-01
The improved DPC-U conductor consisting of 648 chrome plated NbTi strands was fabricated and its stability has been investigated using 1/24 sub-size conductor. In the stability experiment, the inductive heating method was applied to originate initial normal zone. Since it is difficult to calculate the inductive heating energy deposited on the conductor because of complicate geometry of the twisted multi-strand cable, inductive heating energy had to be experimentally evaluated using calorimetric method. The heating energy is in proportion to integration of square of an applied sinusoidal wave pulsed current over the heating period. The experimental result shows the proportional constants for the conductor and conduit are 2.062 x 10 -3 [J/A 2 s] and 0.771 x 10 -3 [J/A 2 s], respectively. The coupling between the eddy currents in the strands and conduit might take effect on the heating energy put in the strands. It was shown this effect was however small in this experiment. Consequently, the inductive heating energy applied in the strands was estimated to be the proportional constant of 1.291 x 10 -3 [J/A 2 s] from the difference of the heat energies in the conductor and conduit. (author)
Advantage of CT scan in muscular pathology. Personal cases and review of the literature
International Nuclear Information System (INIS)
Laroche, M.; Rousseau, H.; Mazieres, B.; Bonafe, A.; Joffre, F.; Arlet, J.
1989-01-01
The advantage of CT scans in muscular pathology is studied. The scan, in addition to the diagnosis of tumors and muscular abscesses, permits to differentiate primary myopathies from neurogenic atrophies: in the course of myopathies, the muscle volume is preserved and they appear as a hypodensity; in neurogenic atrophies, the muscle volume is reduced with preserved density. The CT scan permits to determine the extension of these lesions. In the course of polymyositis, certain forms of rheumatid arthritis, the scan discloses a trabecular and 'worm-eaten' aspect of the muscles. This is also observed after long-term steroid therapy and other endocrine diseases (hyperthyroidism, osteomalacia) indicating an infra-clinical myopathy. In vertebral osteoporosis with fractures and patients with chronic lumbalgia, very ofter, an atrophy of the spinal muscle is observed. Finally, in the course of acquired kyphosis of the adult patient (camptocormia), the CT scan suggest an isolated myopathy, with late manifestations, of the paravertebral muscles [fr
Advantage of CT scan in muscular pathology. Personal cases and review of the literature
Energy Technology Data Exchange (ETDEWEB)
Laroche, M.; Rousseau, H.; Mazieres, B.; Bonafe, A.; Joffre, F.; Arlet, J.
1989-05-01
The advantage of CT scans in muscular pathology is studied. The scan, in addition to the diagnosis of tumors and muscular abscesses, permits to differentiate primary myopathies from neurogenic atrophies: in the course of myopathies, the muscle volume is preserved and they appear as a hypodensity; in neurogenic atrophies, the muscle volume is reduced with preserved density. The CT scan permits to determine the extension of these lesions. In the course of polymyositis, certain forms of rheumatid arthritis, the scan discloses a trabecular and 'worm-eaten' aspect of the muscles. This is also observed after long-term steroid therapy and other endocrine diseases (hyperthyroidism, osteomalacia) indicating an infra-clinical myopathy. In vertebral osteoporosis with fractures and patients with chronic lumbalgia, very ofter, an atrophy of the spinal muscle is observed. Finally, in the course of acquired kyphosis of the adult patient (camptocormia), the CT scan suggest an isolated myopathy, with late manifestations, of the paravertebral muscles.
Computer-Aided Video Differential Planimetry
Tobin, Michael; Djoleto, Ben D.
1984-08-01
THE VIDEO DIFFERENTIAL PLANIMETER (VDP)1 is a re-mote sensing instrument that can measure minute changes in the area of any object seen by an optical scanning system. The composite video waveforms obtained by scanning the object against a contrasting back-ground are amplified and shaped to yield a sequence of constant amplitude pulses whose polarity distinguishes the studied area from its background and whose varying widths reflect the dynamics of the viewed object. These pulses are passed through a relatively long time-constant capacitor-resistor circuit and are then fed into an integrator. The net integration voltage resulting from the most recent sequence of object-background time pulses is recorded and the integrator is returned to zero at the end of each video frame. If the object's area remains constant throughout the following frame, the integrator's summation will also remain constant. However, if the object's area varies, the positive and negative time pulses entering the integrator will change, and the integrator's summation will vary proportionately. The addition of a computer interface and a video recorder enhances the versatility and the resolving power of the VDP by permitting the repeated study and analysis of selected portions of the recorded data, thereby uncovering the major sources of the object's dynamics. Among the medical and biological procedures for which COMPUTER-AIDED VIDEO DIFFERENTIAL PLANIMETRY is suitable are Ophthalmoscopy, Endoscopy, Microscopy, Plethysmography, etc. A recent research study in Ophthalmoscopy2 will be cited to suggest a useful application of Video Differential Planimetry.
Assessing ScanSAR Interferometry for Deformation Studies
Buckley, S. M.; Gudipati, K.
2007-12-01
There is a trend in civil satellite SAR mission design to implement an imaging strategy that incorporates both stripmap mode and ScanSAR imaging. This represents a compromise between high resolution data collection and a desire for greater spatial coverage and more frequent revisit times. However, mixed mode imaging can greatly reduce the number of stripmap images available for measuring subtle ground deformation. Although ScanSAR-ScanSAR and ScanSAR-stripmap repeat-pass interferometry have been demonstrated, these approaches are infrequently used for single interferogram formation and nonexistent for InSAR time series analysis. For future mission design, e.g., a dedicated US InSAR mission, the effect of various ScanSAR system parameter choices on InSAR time series analysis also remains unexplored. Our objective is to determine the utility of ScanSAR differential interferometry. We will demonstrate the use of ScanSAR interferograms for several previous deformation studies: localized and broad-scale urban land subsidence, tunneling, volcanic surface movements and several examples associated with the seismic cycle. We also investigate the effect of various ScanSAR burst synchronization levels on our ability to detect and make quality measurements of deformation. To avoid the issues associated with Envisat ScanSAR burst alignment and to exploit a decade of InSAR measurements, we simulate ScanSAR data by bursting (throwing away range lines of) ERS-1/2 data. All the burst mode datasets are processed using a Modified SPECAN algorithm. To investigate the effects of burst misalignment, a number of cases with varying degrees of burst overlap are considered. In particular, we look at phase decorrelation as a function of percentage of burst overlap. Coherence clearly reduces as the percentage of overlap decreases and we find a useful threshold of 40-70% burst overlap depending on the study site. In order to get a more generalized understanding for different surface conditions
International Nuclear Information System (INIS)
Mahmoud, Mahmoud Youcef; Bassou, Ghaouti; Salomon, Laurant; Chekroun, Z.; Djamai, Nesrine
2007-01-01
Scanning near-field optical microscopy (SNOM) integrates standard optical methods with scanning probe microscopy (SPM) techniques allowing to collect optical information with resolution well beyond the diffraction limit. We study the influence on image formation of several parameters in scanning near-field microscopy. The numerical calculations have been carried out using the differential method. We investigate a 2D-PSTM configuration with a dielectric rectangular object. We will focus on the collection type SNOM in a constant height scanning mode. Various oscillation patterns are observed from both sides of the nanostructure, which we interpret as interference between the diffracted waves scattered by the nanostructure (with the components of the wave vector parallel to the surface) and the evanescent incident wave above the surface. Using an optical near-field analysis and by calculating the electric field intensity distribution, we investigate the probe-sample distance effect. It is found that the distribution of the intensity related to the electric field is depending on sample-probe distance. We noticed the loss of details in the image and the presence of dramatic oscillations. Also, both of the polarization state of the illuminating light effect and the angle of incidence are investigated. We conclude that a differential method provides physical insight into the main features of the different images
Energy Technology Data Exchange (ETDEWEB)
Mahmoud, Mahmoud Youcef [Laboratoire d' elaboration et caracterisation des materiaux, Groupe de Microscopie et Microanalyse, Universite Djilali Liabes de Sidi Bel-Abbes, Faculte des sciences (Algeria)], E-mail: mahmoudhamoud@yahoo.com; Bassou, Ghaouti [Laboratoire d' elaboration et caracterisation des materiaux, Groupe de Microscopie et Microanalyse, Universite Djilali Liabes de Sidi Bel-Abbes, Faculte des sciences (Algeria); Laboratoire de Physique (LPUB), CNRS UMR 5027, Groupe d' Optique de Champ Proche, Faculte des Sciences Mirande, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47 870, 21078 Dijon Cedex (France); Salomon, Laurant [Laboratoire de Physique (LPUB), CNRS UMR 5027, Groupe d' Optique de Champ Proche, Faculte des Sciences Mirande, Universite de Bourgogne, 9 Avenue Alain Savary, BP 47 870, 21078 Dijon Cedex (France); Chekroun, Z. [Laboratoire d' elaboration et caracterisation des materiaux, Groupe de Microscopie et Microanalyse, Universite Djilali Liabes de Sidi Bel-Abbes, Faculte des sciences (Algeria); Djamai, Nesrine [Laboratoire de telecommunications et de traitement numerique du signal (LTTNS), Universite Djilali Liabes de Sidi Bel-Abbes, Faculte des sciences de l' ingenieur, Departement d' electronique (Algeria)
2007-08-25
Scanning near-field optical microscopy (SNOM) integrates standard optical methods with scanning probe microscopy (SPM) techniques allowing to collect optical information with resolution well beyond the diffraction limit. We study the influence on image formation of several parameters in scanning near-field microscopy. The numerical calculations have been carried out using the differential method. We investigate a 2D-PSTM configuration with a dielectric rectangular object. We will focus on the collection type SNOM in a constant height scanning mode. Various oscillation patterns are observed from both sides of the nanostructure, which we interpret as interference between the diffracted waves scattered by the nanostructure (with the components of the wave vector parallel to the surface) and the evanescent incident wave above the surface. Using an optical near-field analysis and by calculating the electric field intensity distribution, we investigate the probe-sample distance effect. It is found that the distribution of the intensity related to the electric field is depending on sample-probe distance. We noticed the loss of details in the image and the presence of dramatic oscillations. Also, both of the polarization state of the illuminating light effect and the angle of incidence are investigated. We conclude that a differential method provides physical insight into the main features of the different images.
An interchangeable scanning Hall probe/scanning SQUID microscope
Energy Technology Data Exchange (ETDEWEB)
Tang, Chiu-Chun; Lin, Hui-Ting; Wu, Sing-Lin [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Chen, Tse-Jun; Wang, M. J. [Institute of Astronomy and Astrophysics, Academia Sinica, Taipei 10617, Taiwan (China); Ling, D. C. [Department of Physics, Tamkang University, Tamsui Dist., New Taipei City 25137, Taiwan (China); Chi, C. C.; Chen, Jeng-Chung [Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan (China); Frontier Research Center on Fundamental and Applied Sciences of Matters, National Tsing Hua University, Hsinchu 30013, Taiwan (China)
2014-08-15
We have constructed a scanning probe microscope for magnetic imaging, which can function as a scanning Hall probe microscope (SHPM) and as a scanning SQUID microscope (SSM). The scanning scheme, applicable to SHPM and SSM, consists of a mechanical positioning (sub) micron-XY stage and a flexible direct contact to the sample without a feedback control system for the Z-axis. With the interchangeable capability of operating two distinct scanning modes, our microscope can incorporate the advantageous functionalities of the SHPM and SSM with large scan range up to millimeter, high spatial resolution (⩽4 μm), and high field sensitivity in a wide range of temperature (4.2 K-300 K) and magnetic field (10{sup −7} T-1 T). To demonstrate the capabilities of the system, we present magnetic images scanned with SHPM and SSM, including a RbFeB magnet and a nickel grid pattern at room temperature, surface magnetic domain structures of a La{sub 2/3}Ca{sub 1/3}MnO{sub 3} thin film at 77 K, and superconducting vortices in a striped niobium film at 4.2 K.
International Nuclear Information System (INIS)
Raju, S.; Kumar, N.S. Arun; Jeyaganesh, B.; Mohandas, E.; Mudali, U. Kamachi
2007-01-01
The thermal stability and crystallization kinetics of a Ni- (Cr, Si, Fe, B, C, P) based amorphous brazing foil have been investigated by non-isothermal differential scanning calorimetry. The glass transition temperature T g , is found to be 720 ± 2 K. The amorphous alloy showed three distinct, yet considerably overlapping crystallization transformations with peak crystallization temperatures centered around 739, 778 and 853 ± 2 K, respectively. The solidus and liquidus temperatures are estimated to be 1250 and 1300 ± 2 K, respectively. The apparent activation energies for the three crystallization reactions have been determined using model free isoconversional methods. The typical values for the three crystallization reactions are: 334, 433 and 468 kJ mol -1 , respectively. The X-ray diffraction of the crystallized foil revealed the presence of following compounds Ni 3 B (Ni 4 B 3 ), CrB, B 2 Fe 15 Si 3 , CrSi 2 , and Ni 4.5 Si 2 B
The ''liver scan'' appearance in cholescintigraphy. A sign of complete common bile duct obstruction
International Nuclear Information System (INIS)
Noel, A.W.; Velchik, M.G.; Alavi, A.
1985-01-01
One hundred consecutive Tc-99m IDA hepatobiliary scans were reviewed revealing 14 scans (14%), that showed nonvisualization of the common bile duct (CBD), gallbladder (GB), and small bowel (SB), but good hepatic uptake of Tc-99m IDA derivative, a pattern designated by us as ''the liver scan appearance.'' In 11 of 14 cases (79%), the diagnosis of complete CBD obstruction was confirmed by surgery, percutaneous transhepatic cholangiogram (PTC), endoscopic retrograde cholangiopancreatography (ERCP), and/or percutaneous needle biopsy (PBx). Common bile duct obstruction was suspected but not proven in the other three cases. The cholescintigraphic, ultrasound, PTC, ERCP, intraoperative cholangiogram, clinical, laboratory, and surgical findings are presented and correlated. The ''liver scan-appearance'' by cholescintigraphy should suggest a diagnosis of complete common bile duct obstruction; however, it does not specifically differentiate between stone or tumor as the cause of obstruction
Fast-Scan DSC and its role in pharmaceutical physical form characterisation and selection.
Ford, James L; Mann, Timothy E
2012-04-01
Conventional rate Differential Scanning Calorimetry (DSC) has been used for many years as a tool in the analysis of pharmaceutical materials. In recent years an extension of the technique to include fast heating and cooling rates has become more prevalent. Broadly termed Fast-Scan DSC, this review examines the current applications of this technique to the characterisation and selection of pharmaceutical materials. Its increasing use encompasses the characterisation of amorphousness in crystalline materials, the characterisation of polymorphs and polymorphic transitions, the solubility of drugs in polymers, and characterisation of dosage forms. Notwithstanding the advantages of analytical speed in analytical turnover, the review emphasises the advantages of Fast-Scan DSC in its sensitivity which allows the separation of overlapping thermal events, the reduction it provides in degradation during the scanning process and its role in determining solubility in waxy and polymeric based systems. A comparison of the uses of Fast-Scan DSC to modulated DSC techniques and localised thermal analysis is also given. © 2011 Elsevier B.V. All rights reserved.
International Nuclear Information System (INIS)
Jin, Seong Chan; Choi, Yun Young; Cho, Suk Shin
2003-01-01
Increased periarticular uptake could be associated with peripheral bone marrow expansion in cancer patients with axial bone marrow metastasis. We compared bone scan and bone marrow scan to investigate whether the increased whole body count in patients with increased periarticular uptake on bone scan is useful in the diagnosis of axial marrow metastasis, and evaluate the role of additional bone marrow scan in these cases. Twelve patients with malignant diseases who showed increased periarticular uptake on bone scan were included. Whole body count was measured on bone scan and it is considered to be increased when the count is more than twice of other patients. Bone marrow scan was taken within 3-7 days. Five hematologic malignancy, 3 stomach cancer, 2 breast cancer, 1 prostate cancer and 1 lung canner were included. All three patients with increased whole body count on bone scan showed axial marrow suppression and peripheral marrow expansion. Eight of 9 patients without increased whole body count showed axial marrow suppression and peripheral marrow expansion. One turned out to be blastic crisis of chronic myelogeneous leukemia, and seven showed normal axial marrow with peripheral marrow expansion in chronic anemia of malignancy. The last one without increased whole body count showed normal bone marrow scan finding. Increased whole body count on bone scan could be a clue to axial bone marrow metastasis in cancer patients with increased periarticular uptake, and bone marrow scan is a valuable method for differential diagnosis in these cases
NEW SCANNING DEVICE FOR SCANNING TUNNELING MICROSCOPE APPLICATIONS
SAWATZKY, GA; Koops, Karl Richard
A small, single piezo XYZ translator has been developed. The device has been used as a scanner for a scanning tunneling microscope and has been tested successfully in air and in UHV. Its simple design results in a rigid and compact scanning unit which permits high scanning rates.
Energy Technology Data Exchange (ETDEWEB)
Navia, Paloma; Troncoso, Jacobo [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis [Departamento de Fisica Aplicada, Facultad de Ciencias de Ourense, Campus As Lagoas, 32004 Ourense (Spain)], E-mail: romani@uvigo.es
2008-11-15
A new method for determining isobaric thermal expansivity of liquids as a function of temperature and pressure through calorimetric measurements against pressure is described. It is based on a previously reported measurement technique, but due to the different kind of calorimeter and experimental set up, a new calibration procedure was developed. Two isobaric thermal expansivity standards are needed; in this work, with a view on the quality of the available literature data, hexane and water are chosen. The measurements were carried out in the temperature and pressure intervals (278.15 to 348.15) K and (0.5 to 55) MPa for a set of liquids, and experimental values are compared with the available literature data in order to evaluate the precision of the experimental procedure. The analysis of the results reveals that the proposed methodology is highly accurate for isobaric thermal expansivity determination, and it allows obtaining a precise characterisation of the temperature and pressure dependence of this thermodynamic coefficient.
International Nuclear Information System (INIS)
Navia, Paloma; Troncoso, Jacobo; Romani, Luis
2008-01-01
A new method for determining isobaric thermal expansivity of liquids as a function of temperature and pressure through calorimetric measurements against pressure is described. It is based on a previously reported measurement technique, but due to the different kind of calorimeter and experimental set up, a new calibration procedure was developed. Two isobaric thermal expansivity standards are needed; in this work, with a view on the quality of the available literature data, hexane and water are chosen. The measurements were carried out in the temperature and pressure intervals (278.15 to 348.15) K and (0.5 to 55) MPa for a set of liquids, and experimental values are compared with the available literature data in order to evaluate the precision of the experimental procedure. The analysis of the results reveals that the proposed methodology is highly accurate for isobaric thermal expansivity determination, and it allows obtaining a precise characterisation of the temperature and pressure dependence of this thermodynamic coefficient
Nuclear scans use radioactive substances to see structures and functions inside your body. They use a special ... images. Most scans take 20 to 45 minutes. Nuclear scans can help doctors diagnose many conditions, including ...
International Nuclear Information System (INIS)
Eguchi, Katsuto; Lin, Yaw-Tyng; Noda, Kiyofumi; Saeki, Kazuhiko; Yonezawa, Masaru; Sekiba, Kaoru; Ochiai, Youji
1987-01-01
Six pregnant women with convulsions between 25 to 40 weeks of gestation were experienced. Among them, 4 patients were diagnosed as having intracranial hemorrhage and two as simple eclampsia. With the aid of brain CT scan, one case of arteriovenous malformation was detected and treated surgically with good prognosis for both the mother and the fetus. Two patients were diagnosed to have cerebral hemorrhage with subsequent penetration into the lateral ventricles and were treated conservatively. Their fetuses were delivered alive by cesarean section, but the mothers expired. The other patient with cerebral hemorrhage was treated surgically, and both the mother and the fetus survived. One of the simple eclampsia patients was noted to have a growth retarded fetus at 32 weeks of pregnancy with subsequent intra-uterine death, but the mother recovered after conservative treatment. Another patient at 40 weeks of pregnancy was also treated conservatively and both the fetus and the mother survived. Brain CT scan findings differed between these two eclampsia patients; local brain edema for the second patient and generalized brain edema for the first patient. Thus more active application of brain CT scan is recommended in managing pregnant patients with convulsions. (author)
Energy Technology Data Exchange (ETDEWEB)
Eguchi, Katsuto; Lin, Yaw-Tyng; Noda, Kiyofumi; Saeki, Kazuhiko; Yonezawa, Masaru; Sekiba, Kaoru; Ochiai, Youji
1987-06-01
Six pregnant women with convulsions between 25 to 40 weeks of gestation were experienced. Among them, 4 patients were diagnosed as having intracranial hemorrhage and two as simple eclampsia. With the aid of brain CT scan, one case of arteriovenous malformation was detected and treated surgically with good prognosis for both the mother and the fetus. Two patients were diagnosed to have cerebral hemorrhage with subsequent penetration into the lateral ventricles and were treated conservatively. Their fetuses were delivered alive by cesarean section, but the mothers expired. The other patient with cerebral hemorrhage was treated surgically, and both the mother and the fetus survived. One of the simple eclampsia patients was noted to have a growth retarded fetus at 32 weeks of pregnancy with subsequent intra-uterine death, but the mother recovered after conservative treatment. Another patient at 40 weeks of pregnancy was also treated conservatively and both the fetus and the mother survived. Brain CT scan findings differed between these two eclampsia patients; local brain edema for the second patient and generalized brain edema for the first patient. Thus more active application of brain CT scan is recommended in managing pregnant patients with convulsions.
Examination of living fungal spores by scanning electron microscopy
International Nuclear Information System (INIS)
Read, N.D.; Lord, K.M.
1991-01-01
Ascospores of Sordaria macrospora germinated and produced hyphae exhibiting normal growth and differentiation after examination by scanning electron microscopy and following numerous, different preparative protocols. Seventy-nine to ninety-nine percent of the ascospores retained normal viability after being observed in the fully frozen-hydrated, partially freeze-dried, and vacuum-dried states at accelerating voltages of 5 and 40 keV. Hyphae did not survive these treatments. From these observations it is concluded that ascospores of S. macrospora can remain in a state of suspended animation while being observed in the scanning electron microscope. The ascospores also survived, but with reduced viability: 6 h in glutaraldehyde and formaldehyde, 6 h in OsO4, or 2 h in glutaraldehyde and formaldehyde followed by 2 h in OsO 4 . However, the ascospores did not germinate after dehydration in ethanol. (author)
Microstructural and thermal study of Al-Si-Mg/melon shell ash particulate composite
Directory of Open Access Journals (Sweden)
M. Abdulwahab
Full Text Available The microstructural study via scanning electron microscope (SEM and thermal study via differential scanning calorimetric (DSC study of Al-7%Si-0.3Mg/melon shell ash particulate composite has been carried out. The melon shell ash was used in the production of MMC ranging from 5% to 20% at interval of 5% addition using stir casting method. The melon shell ash was characterized using X-ray fluorescent (XRF that reveal the presence of CaO, SiO2, Al2O3, MgO, and TiO2 as major compounds. The composite was machined and subjected to heat treatment. Microstructural analyses of the composite produced were done using scanning electron microscope (SEM. The microstructure obtained reveals a dark ceramic (reinforcer and white metallic phase. Equally, the 5 wt% DSC result gives better thermal conductivity than other proportions (10 wt%, 15 wt%, and 20 wt%. These results showed that an improved property of Al-Si-Mg alloy was achieved using melon shell ash particles as reinforcement up to a maximum of 20 wt% for microstructural and 5% wt DSC respectively. Keywords: Microstructural analysis, Melon shell ash, Stir casting, X-ray fluorescent, Reinforcement, Composite
International Nuclear Information System (INIS)
Matricarde Falleiro, Rafael M.; Meirelles, Antonio J.A.; Kraehenbuehl, Maria A.
2010-01-01
(Vapor + liquid) equilibrium (VLE) data for three binary mixtures of saturated fatty acids were obtained by differential scanning calorimetry (DSC). However, changes in the calorimeter pressure cell and the use of hermetic pans with holes (φ = 250 mm) in the lids were necessary to make it possible to apply this analytical technique, obtaining accurate results with smaller samples and shorter operational times. The systems evaluated in this study were: myristic acid (C 14:0 ) + palmitic acid (C 16:0 ), myristic acid (C 14:0 ) + stearic acid (C 18:0 ), and palmitic acid (C 16:0 ) + stearic acid (C 18:0 ), all measured at 50 mm Hg and with mole fractions between 0.0 and 1.0 in relation to the most volatile component of each diagram. The fugacity coefficients for the components in the vapor phase were calculated using the Hayden and O'Connell method [J.G. Hayden, J.P. O'Connell, Ind. Eng. Chem. Process Design Develop. 14 (3) (1975) 209-216] and the activity coefficients for the liquid phase were correlated with the traditional g E models (NRTL [H. Renon, J.M. Prausnitz, Aiche J. 14 (1968) 135-144], UNIQUAC [D.S. Abrams, J.M. Prausnitz, Aiche J. 21 (1975) 116-128], and Wilson [J.M. Prausnitz, N.L. Linchtenthaler, E.G. Azevedo, Molecular Thermodynamics of Fluid-phase Equilibria, River-Prentice Hall, Upper Saddle, 1999]). The sets of parameters were then compared in order to determine which adjustments best represented the VLE.
Energy Technology Data Exchange (ETDEWEB)
Albert, Nathalie L.; Winkelmann, Isabel; Wenter, Vera; Mille, Erik; Todica, Andrei; Brendel, Matthias; Bartenstein, Peter [Ludwig-Maximilians-University Munich, Department of Nuclear Medicine, Munich (Germany); Suchorska, Bogdana; Tonn, Joerg-Christian [Ludwig-Maximilians-University Munich, Department of Neurosurgery, Munich (Germany); Schmid-Tannwald, Christine [Ludwig-Maximilians-University Munich, Institute for Clinical Radiology, Munich (Germany); La Fougere, Christian [University of Tuebingen, Division of Nuclear Medicine and Clinical Molecular Imaging, Department of Radiology, Tuebingen (Germany)
2016-06-15
Current guidelines for glioma imaging by positron emission tomography (PET) using the amino acid analogue O-(2-[{sup 18}F]fluoroethyl)-L-tyrosine ({sup 18}F-FET) recommend image acquisition from 20-40 min post injection (p.i.). The maximal tumour-to-background evaluation (TBR{sub max}) obtained in these summation images does not enable reliable differentiation between low and high grade glioma (LGG and HGG), which, however, can be achieved by dynamic {sup 18}F-FET-PET. We investigated the accuracy of tumour grading using TBR{sub max} values at different earlier time points after tracer injection. Three hundred and fourteen patients with histologically proven primary diagnosis of glioma (131 LGG, 183 HGG) who had undergone 40-min dynamic {sup 18}F-FET-PET scans were retrospectively evaluated. TBR{sub max} was assessed in the standard 20-40 min summation images, as well as in summation images from 0-10 min, 5-15 min, 5-20 min, and 15-30 min p.i., and kinetic analysis was performed. TBR{sub max} values and kinetic analysis were correlated with histological classification. ROC analyses were performed for each time frame and sensitivity, specificity, and accuracy were assessed. TBR{sub max} values in the earlier summation images were significantly better for tumour grading (P < 0.001) when compared to standard 20-40 min scans, with best results for the early 5-15 min scan. This was due to higher TBR{sub max} in the HGG (3.9 vs. 3.3; p < 0.001), while TBR{sub max} remained nearly stable in the LGG (2.2 vs. 2.1). Overall, accuracy increased from 70 % in the 20-40 min analysis to 77 % in the 5-15 min images, but did not reach the accuracy of dynamic analysis (80 %). Early TBR{sub max} assessment (5-15 min p.i.) is more accurate for the differentiation between LGG and HGG than the standard static scan (20-40 min p.i.) mainly caused by the characteristic high {sup 18}F-FET uptake of HGG in the initial phase. Therefore, when dynamic {sup 18}F-FET-PET cannot be performed
... results on a PET scan. Blood sugar or insulin levels may affect the test results in people with diabetes . PET scans may be done along with a CT scan. This combination scan is called a PET/CT. Alternative Names Brain positron emission tomography; PET scan - brain References Chernecky ...
Energy Technology Data Exchange (ETDEWEB)
Gautier, B.; Bosseboeuf, G.
1995-11-01
The R and D has been developing for about ten years, through the MAGIC software, a modeling program on the propagation of fire in power plants. The potential fuels in a power plant are mainly limited to the oils existing in engines and control systems, and electric cables. Those cables present a complex combustion due to their fire-resistant design. In order to study that combustion, two test benches, the PITCAIRN oven and the CALORIMETRE EDF/CNRS have been linked. This report presents briefly the experimental installation, then it comments on the first experimental data obtained with two types of samples, a PVC and an EPR-Hypalon cable. The tested cables are selected from those commonly used in French Nuclear Power Plants. They present complex components (fire-retarding chemical agents, mechanical reinforcement). The data show that the behavior of those cables cannot be reduced to a mass loss rate associated to a constant Heat of Combustion. The Heat of Combustion of the PVC cable tested varies little at the beginning of the pyrolysis from 5 kJ.g{sup -1} to 10 kJ.g{sup -1}, then increases quickly up to 30 kJ.g{sup -1}. In the same way, the EPR-Hypalon cable shows a continuous and slow increase of the Heat of Combustion from 1 kJ.g{sup -1} to 20 kJ.g{sup -1} during the pyrolysis, then rises quickly up to 40 kJ.g{sup -1} at the end. Those data corroborate the thesis of the dilution of flammable species by fire-retarding agents, which lower the Heat of combustion but seems to disappear at the end of the pyrolysis. (authors). 7 refs., 6 figs.
False positive and false negative FDG-PET scans in various thoracic diseases
International Nuclear Information System (INIS)
Chang, Jung Min; Lee, Hyun Ju; Goo, Jin Mo; Lee, Ho Young; Lee, Jong Jin; Chung, June Key; Im, Jung Gi
2006-01-01
Fluorodeoxygucose (FDG)-positron emission tomography (PET) is being used more and more to differentiate benign form malignant focal lesions and it has been shown to be more efficacious than conventional chest computed tomography (CT). However, FDG is not a cancer-specific agent, and false positive findings in benign diseases have been reported. Infectious diseases (mycobacterial, fungal, bacterial infection), sarcoidosis, radiation pneumonitis and post-operative surgical conditions have shown intense uptake on PET scan. On the other hand, tumors with low glycolytic activity such as adenomas, bronchioloalveolar carcinomas, carcinoid tumors, low grade lymphomas and small sized tumors have revealed false negative findings on PET scan, Furthermore, in diseases located near the physiologic uptake sites (heart, bladder, kidney, and liver), FDG-PET should be complemented with other imaging modalities to confirm results and to minimize false negative findings. Familiarity with these false positive and negative findings will help radiologists interpret PET scans more accurately and also will help to determine the significance of the findings. In this review, we illustrate false positive and negative findings of PET scan in a variety of diseases
[Scans without Evidence of Dopamine Deficit (SWEDDs)].
Mukai, Yohei; Murata, Miho
2016-01-01
Dopamine transporter (DaT) single-photon emission computed tomography (SPECT) and [18F]fluoro-L-DOPA ([18F]DOPA) positron emission tomography (PET) facilitate the investigation of dopaminergic hypofunction in neurodegenerative diseases. DaT SPECT and [18F]DOPA PET have been adopted as survey tools in clinical trials. In a large study on Parkinson's disease, 4-15% of subjects clinically diagnosed with early-stage Parkinson's disease had normal dopaminergic functional imaging scans. These are called Scans without Evidence of Dopamine Deficit (SWEDDs), and are considered to represent a state different from Parkinson's disease. Neurological diseases that exhibit parkinsonism and have normal dopaminergic cells in the nigrostriatal system (e.g., essential tremor, psychogenic parkinsonism, DOPA-responsive dystonia, vascular parkinsonism, drug-induced parkinsonism, manganism, brain tumor, myoclonus-dystonia (DYT11), and fragile X syndrome) might be diagnosed with SWEDDs. True bradykinesia with fatigue or decrement may be useful for distinguishing between Parkinson's disease and SWEDDs. However, because SWEDDs encompass many diseases, their properties may not be uniform. In this review, we discuss DaT SPECT, the concept of SWEDDs, and differential diagnosis.
International Nuclear Information System (INIS)
Shapiro, B.
1986-01-01
Radionuclide scanning is the production of images of normal and diseased tissues and organs by means of the gamma-ray emissions from radiopharmaceutical agents having specific distributions in the body. The gamma rays are detected at the body surface by a variety of instruments that convert the invisible rays into visible patterns representing the distribution of the radionuclide in the body. The patterns, or images, obtained can be interpreted to provide or to aid diagnoses, to follow the course of disease, and to monitor the management of various illnesses. Scanning is a sensitive technique, but its specificity may be low when interpreted alone. To be used most successfully, radionuclide scanning must be interpreted in conjunction with other techniques, such as bone radiographs with bone scans, chest radiographs with lung scans, and ultrasonic studies with thyroid scans. Interpretation is also enhanced by providing pertinent clinical information because the distribution of radiopharmaceutical agents can be altered by drugs and by various procedures besides physiologic and pathologic conditions. Discussion of the patient with the radionuclide scanning specialist prior to the study and review of the results with that specialist after the study are beneficial
A log-Weibull spatial scan statistic for time to event data.
Usman, Iram; Rosychuk, Rhonda J
2018-06-13
Spatial scan statistics have been used for the identification of geographic clusters of elevated numbers of cases of a condition such as disease outbreaks. These statistics accompanied by the appropriate distribution can also identify geographic areas with either longer or shorter time to events. Other authors have proposed the spatial scan statistics based on the exponential and Weibull distributions. We propose the log-Weibull as an alternative distribution for the spatial scan statistic for time to events data and compare and contrast the log-Weibull and Weibull distributions through simulation studies. The effect of type I differential censoring and power have been investigated through simulated data. Methods are also illustrated on time to specialist visit data for discharged patients presenting to emergency departments for atrial fibrillation and flutter in Alberta during 2010-2011. We found northern regions of Alberta had longer times to specialist visit than other areas. We proposed the spatial scan statistic for the log-Weibull distribution as a new approach for detecting spatial clusters for time to event data. The simulation studies suggest that the test performs well for log-Weibull data.
Pulmonary aspergilloma: A rare differential diagnosis to lung cancer after positive FDG PET scan
Directory of Open Access Journals (Sweden)
Franziska Spycher
2014-01-01
Full Text Available Early diagnosis and treatment of lung cancer, one of the leading causes of cancer-related death, is important to improve morbidity and mortality. Therefore any suspect solitary pulmonary nodule should prompt the pursuit for a definitive histological diagnosis. We describe the case of a 55-years-old male ex-smoker, who was admitted to our hospital due to recurrent hemoptysis and dry cough. A CT scan showed an irregular nodule of increasing size (28 mm in diameter in the left lower lobe (LLL. A whole body PET-CT scan (643 MBq F-18 FDG i.v. was performed and confirmed an avid FDG uptake of the nodule in the LLL, highly suspicious of lung cancer, without any evidence of lymphogenic or hematogenic metastasis. Bronchoscopy was not diagnostic and due to severe adhesions after prior chest trauma and the central location of the nodule, a lobectomy of the LLL was performed. Surprisingly, histology showed a simple aspergilloma located in a circumscribed bronchiectasis with no evidence of malignancy. This is a report of an informative example of an aspergilloma, which presented with symptoms and radiological features of malignant lung cancer.
International Nuclear Information System (INIS)
Morales, Rosanna; Cano, Roque; Delgado, Ricardo; Munive, Carlos
2014-01-01
Objectives: To report findings in bone scans for breast cancer patients with mastectomy and breast reconstruction with transverse rectus abdominis myocutaneous flap (TRAM). Material and Methods: Inclusion criteria were: confirmed breast cancer, mastectomy, breast reconstruction with TRAM flap and bone scan performed after TRAM. Exclusion criteria were: Absence of bone scan image, breast reconstruction by other approaches. Results: Absence of uptake in TRAM flap in six patients, diminished uptake in skin near TRAM, with peripheral increased uptake in three and increased uptake in TRAM flap, in a patient with cancer recurrence, confirmed by biopsy. Conclusions: Bone scans in breast cancer patients with mastectomy and TRAM flap can have different imaging presentations, procedure details diminish reporting errors. TRAM flap may present fat necrosis areas, which should be differentiated from recurrence in bone scans. Additional imaging and biopsy will be needed to diagnose this finding. (authors).
Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter
Energy Technology Data Exchange (ETDEWEB)
Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao [Faculty of Pure and Applied Sciences, University of Tsukuba, Tsukuba, Ibaraki, 305-8573 (Japan)
2016-01-28
Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data.
Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter
International Nuclear Information System (INIS)
Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao
2016-01-01
Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke’s tabulated data
Quantitative phase tomography by using x-ray microscope with Foucault knife-edge scanning filter
Watanabe, Norio; Tsuburaya, Yuji; Shimada, Akihiro; Aoki, Sadao
2016-01-01
Quantitative phase tomography was evaluated by using a differential phase microscope with a Foucault knife-edge scanning filter. A 3D x-ray phase image of polystyrene beads was obtained at 5.4 keV. The reconstructed refractive index was fairly good agreement with the Henke's tabulated data.
Energy Technology Data Exchange (ETDEWEB)
Ino, Chiyonori; Yamashita, Toshio; Hanaoka, Mako; Kumazawa, Tadami
1984-10-01
Submandibular gland function was tested with /sup 99m/Tc-pertechnetate scan 10 days and 3-4 weeks after the onset Bell's palsy, and the results and prognoses were correlated. In the first report the cases were divided into groups A, B and C, and this time group D classified in S.S.R. was poor. Groups A and D can be differentiated by submandibular gland scan within 10 days after the onset; that is to say, the prognosis of more than half the cases can be determined in this early phase. Especially, it is noticeable that group D showing the poor prognosis is differentiated within 10 days after the onset. This method was compared with other tests of facial palsy. Four to five weeks after the onset all tests were of equal accuracy in predicting the prognosis of each group. Within 10 days after the onset, however, submandibular gland scan seems to be more useful than the other tests.
Directory of Open Access Journals (Sweden)
Carlos Luna Vázquez
2012-07-01
Full Text Available This paper presents a fast calibration method to determine the transfer function for spatial correspondences in image transmission devices with Incoherent Optical Fiber Bundles (IOFBs, by performing a scan of the input, using differential patterns generated from a Gray code (Differential Gray-Code Space Encoding, DGSE. The results demonstrate that this technique provides a noticeable reduction in processing time and better quality of the reconstructed image compared to other, previously employed techniques, such as point or fringe scanning, or even other known space encoding techniques.
Sukontason, Kabkaew L; Sukontason, Kom; Piangjai, Somsak; Boonchu, Noppawan; Chaiwong, Tarinee; Vogtsberger, Roy C; Kuntalue, Budsabong; Thijuk, Natchanart; Olson, Jimmy K
2003-06-01
The larval morphology of Chrysomya megacephala (Fabricius) is presented using scanning electron microscopy (SEM). Extreme similarity of this species to Chrysomya rufifacies (Macquart), a species usually found concurrently inhabiting decomposing human corpses in Thailand, is seen only in the first-instar larvae. The relative thickness of the branches of the posterior spiracular hairs in these species could be used to differentiate them in this developmental stage. In contrast, the "hairy" appearance of C. rufifacies allows second- and third-instar larvae to be easily distinguished. Results of this study should help in future endeavors to differentiate C. megacephala from other larvae found in decomposing human corpses in Thailand.
Energy Technology Data Exchange (ETDEWEB)
Prez, L de; Pooter, J de; Jansen, B [VSL, Delft (Netherlands); Wolthaus, J; Asselen, B van; Woodings, S; Soest, T; Kok, J; Raaymakers, B [University Medical Center Utrecht, Utrecht (Netherlands)
2016-06-15
Purpose: Reference dosimetry in MR-guided radiotherapy is performed in the presence of a B-field. As a consequence the response of ionization chambers changes considerably and depends on parameters not considered in traditional reference dosimetry. Therefore future Codes of Practices need ionization chamber correction factors to correct for both the change in beam quality and the presence of a B-field. The objective was to study the feasibility of water calorimetric absorbed-dose measurements in a 1.5 T B-field of an MRLinac and the direct measurement of kQ,B calibration of ionization chambers. Methods: Calorimetric absorbed dose to water Dw was measured with a new water calorimeter in the bore of an MRLinac (TPR20,10 of 0.702). Two waterproof ionization chambers (PTW 30013, IBA FC-65G) were calibrated inside the calorimeter phantom (ND,w,Q,B). Both measurements were normalized to a monitor ionization chamber. Ionization chamber measurements were corrected for conventional influence parameter. Based on the chambers’ Co-60 calibrations (ND,w,Q0), measured directly against the calorimeter. In this study the correction factors kQ,B was determined as the ratio of the calibration coefficients in the MRLinac and in Co-60. Additionally, kB was determined based on kQ values obtained with the IAEA TRS-398 Code of Practice. Results: The kQ,B factors of the ionization chambers mentioned above were respectively 0.9488(8) and 0.9445(8) with resulting kB factors of 0.961(13) and 0.952(13) with standard uncertainties on the least significant digit(s) between brackets. Conclusion: Calorimetric Dw measurements and calibration of waterproof ionization chambers were successfully carried out in the 1.5 T B-field of an MRLinac with a standard uncertainty of 0.7%. Preliminary kQ,B and kB factors were determined with standard uncertainties of respectively 0.8% and 1.3%. The kQ,B agrees with an alternative method within 0.4%. The feasibility of water calorimetry in the presence of B
Energy Technology Data Exchange (ETDEWEB)
Santos, A.M.C.; Santana, M.A.; Gomide, F.T.F.; Oliveira, J.S.; Vilas Boas, F.A.S.; Santoro, M.M.; Teixera, K.N. [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Biologicas (ICB). Dept. de Bioquimica e Imunologia; Miranda, A.A.C.; Biondi, I. [Universidade Estadual de Feira de Santana (UEFS), BA (Brazil). Dept. de Ciencias Biologicas; Vasconcelos, A.B.; Bemquerer, M.P. [EMBRAPA Recursos Geneticos e Biotecnologia, Brasilia, DF (Brazil). Parque Estacao Biologica (PqEB)
2008-07-01
Full text: {alpha}-Trypsin is a serine-protease with a polypeptide chain of 223 amino acid residues and six disulfide bridges. It is a globular protein with predominance of antiparallel {beta}-sheet secondary structure and it has two domains with similar structures. In the present work, a stability study of {alpha}-trypsin in the acid pH range was performed and physical-chemical denaturation parameters were measured by using differential scanning calorimetry (DSC). The {alpha}-trypsin has a shelf-life (t{sub 95%}) of about ten months at pH 3.0 and 4 deg C and its hydrolysis into the {psi}-trypsin isoform is negligible during six months as monitored by mass spectrometry (Micromass Q-ToF). The observed {delta}H{sub cal}/{delta}H{sub vH} ratio is close to unity for {alpha}-trypsin denaturation, which suggests the occurrence of a two-state transition, devoid of molten-globule intermediates. At pH 3.0, {alpha}-trypsin unfolded with T{sub m} 325.9 K and {delta}H= 99.10 kcal mol{sup -1}, and the change in heat capacity between the native and unfolded forms of the protein was estimated to be 1.96 {+-} 0.18 kcal mol{sup -1} K{sup -1}. The stability of {alpha}-trypsin calculated at 298 K and at pH 3.0 was {delta}G{sub U} = 6.10 kcal mol{sup -1}. These values are in the range expected for a small globular protein. These results show that the thermodynamic parameters for unfolding of {beta}-trypsin do not change substantially after its conversion to {alpha}-trypsin.
Diagnostic performance of shear wave elastography of the breast according to scanning orientation.
Kim, Solip; Choi, SeonHyeong; Choi, Yoonjung; Kook, Shin-Ho; Park, Hee Jin; Chung, Eun Chul
2014-10-01
To evaluate the influence of the scanning orientation on diagnostic performance measured by the mean elasticity, maximum elasticity, and fat-to-lesion elasticity ratio on ultrasound-based shear wave elastography in differentiating breast cancers from benign lesions. In this study, a total of 260 breast masses from 235 consecutive patients were observed from March 2012 to November 2012. For each lesion, the mean elasticity value, maximum elasticity value, and fat-to-lesion ratio were measured along two orthogonal directions, and all values were compared with pathologic results. There were 59 malignant and 201 benign lesions. Malignant masses showed higher mean elasticity, maximum elasticity, and fat-to-lesion ratio values than benign lesions (P masses; and mean elasticity, 0.392, for anterior mammary fat. Mean elasticity, maximum elasticity, and fat-to-lesion elasticity ratio values were helpful in differentiating benign and malignant breast masses. The scanning orientation did not significantly affect the diagnostic performance of shear wave elastography for breast masses. © 2014 by the American Institute of Ultrasound in Medicine.
International Nuclear Information System (INIS)
Penningsfeld, F.P.
1987-06-01
Density profiles of the Wendelstein VII-A plasma as measured by Thomson scattering are used to calculate the temporally and spatially varying power density of the neutral beam shinethrough on the torus calorimeter for several shot series. The total energy deposited by the three beam species is obtained by integrating the transmitted power density in space and time. This global quantity is compared with the calorimetric measurements routinely performed for each shot. The agreement between calculated and measured energy is found to be ΔE/E = 2.3 ± 11% confirming the error estimation for the NEUDEN program used, which was only slightly modified to calculate the power density transmitted in the target plane. From this good agreement it is concluded that the program contains a realistic beam model and reliable cross-sections for the beam attenuation which is important for further applications. Furthermore, the same comparison was done with old results of the ODIN code by analyzing the corresponding raw data as far as they could be recovered, obtaining a similarly good consistency. A possible increase of 10 to 20% of the beam stopping cross section which could be expected for Wendelstein VII-A conditions by the effect of multistep collision processes as suggested by Boley et al. is discussed also. (orig.)
International Nuclear Information System (INIS)
Xu, Wei; Gao, Bo; Xu, Kun; Lee, Yi-Kuen; Pan, Liang; Chiu, Yi
2017-01-01
We systematically study the effect of two packaging configurations for the CMOS thermoresistive micro calorimetric flow (TMCF) sensors: S-type with the sensor chip protrusion-mounted on the flow channel wall and E-type with the sensor chip flush-mounted on the flow channel wall. Although the experimental results indicated that the sensitivity of the S-type was increased by more than 30%; the corresponding flow range as compared to the E-type was dramatically reduced by 60% from 0–11 m s −1 to 0–4.5 m s −1 . Comprehensive 2D CFD simulation and in-house developed 3D numerical simulations based on the gas-kinetic scheme were applied to study the flow separation of these two packaging designs with the major parameters. Indeed, the S-type design with the large protrusion would change the local convective heat transfer of the TMCF sensor and dramatically decrease the sensors’ performance. In addition, parametric CFD simulations of the packaging designs provide inspiration to propose a novel general flow regime map (FRM), i.e. normalized protrusion d * versus reduced chip Reynolds number Re * , where the critical boundary curve for the flow separation of TMCF sensors was determined at different channel aspect ratios. The proposed FRM can be a useful guideline for the packaging design and manufacturing of different micro thermal flow sensors. (paper)
CT scanning in patients with amputated legs
International Nuclear Information System (INIS)
Huebener, K.H.; Ahlemann, L.M.
1981-01-01
CT scanning after above-knee amputation and below-knee amputation helps to determine the calcium salt content of the examined bones, and to differentiate changes in the surrounding soft parts. By comaring the sides, it is quite easy to detect osteoporotic changes shortly after amputation which would otherwise remain undetected by X-ray film examination. It is equally easy to verify muscular changes, whereas characteristic changes in density allow to determine the share of vacant fat in muscular atrophy. Initial examinations proved the usefulness of CT diagnosis for early detection of dystrophic osseous and muscular changes and also show the possibilities of early therapy control of dystrophy treatment. (orig.) [de
Energy Technology Data Exchange (ETDEWEB)
Lubin, E.; Lewitus, Z.; Rosenfeld, J.; Levi, M. [Beilinson Medical Centre, University of Tel Aviv School of Medicine (Israel)
1969-05-15
Every impairment of the kidneys' blood supply, and the production or excretion of urine, is reflected by abnormal renograms that are not specific enough in the information they provide. The subsequent performance of renal scans with Hippuran {sup 131}I adds information to the topographical distribution of the Hippuran {sup 131}I in the renal parenchyma, and to the dynamics of its transport through the urinary system. The information thus obtained is valuable in itself and is necessary for the correct interpretation of renography. We have found this specially useful in the follow-up of the transplanted kidneys. In cases of anuria following renal transplantation, the renogram is useful for indicating that renal circulation is present in the transplanted kidney but is inadequate as a method to differentiate between other renal and post-renal causes of anuria. The anuric transplanted kidney should be scanned thirty minutes after the injection of Hippuran {sup 131}I. Patterns of complementary results of renograms and renal scannings are presented that correspond to prerenal, renal and postrenal causes of anuria, with all the important therapeutic implications this differential diagnosis has. (author)
Radioiodine concentration by the thymus in differentiated thyroid carcinoma: report of five cases
Energy Technology Data Exchange (ETDEWEB)
Mello, Maria Eduarda; Flamini, Rodrigo C.; Corbo, Rossana; Mamede, Marcelo [Instituto Nacional do Cancer (INCa), Rio de Janeiro, RJ (Brazil). Servico de Medicina Nuclear], e-mail: mamede@inca.gov.br
2009-10-15
The radioactive iodine has been used with great value as a diagnostic and therapeutic method in patients with differentiated thyroid carcinoma previously submitted to total thyroidectomy. False-positive whole-body scans may occur due to misinterpretation of the physiologic distribution of the radioisotope or lack of knowledge on the existence of other pathologies that could eventually present radioiodine uptake. Thymic uptake is an uncommon cause of false-positive whole-body scan, and the mechanism through which it occurs is not completely understood. The present paper reports five cases of patients with differentiated thyroid cancer who presented a mediastinum uptake of radioiodine in a whole-body scan during follow-up. The patients had either histological or radiological confirmation of the presence of residual thymus gland. It is very important to know about the possibility of iodine uptake by the thymus in order to avoid unnecessary treatment, such as surgery or radioiodine therapy. (author)
Monchau, Jean-Pierre; Hameury, Jacques; Ausset, Patrick; Hay, Bruno; Ibos, Laurent; Candau, Yves
2018-05-01
Accurate knowledge of infrared emissivity is important in applications such as surface temperature measurements by infrared thermography or thermal balance for building walls. A comparison of total hemispherical emissivity measurement was performed by two laboratories: the Laboratoire National de Métrologie et d'Essais (LNE) and the Centre d'Études et de Recherche en Thermique, Environnement et Systèmes (CERTES). Both laboratories performed emissivity measurements on four samples, chosen to cover a large range of emissivity values and angular reflectance behaviors. The samples were polished aluminum (highly specular, low emissivity), bulk PVC (slightly specular, high emissivity), sandblasted aluminum (diffuse surface, medium emissivity), and aluminum paint (slightly specular surface, medium emissivity). Results obtained using five measurement techniques were compared. LNE used a calorimetric method for direct total hemispherical emissivity measurement [1], an absolute reflectometric measurement method [2], and a relative reflectometric measurement method. CERTES used two total hemispherical directional reflectometric measurement methods [3, 4]. For indirect techniques by reflectance measurements, the total hemispherical emissivity values were calculated from directional hemispherical reflectance measurement results using spectral integration when required and directional to hemispherical extrapolation. Results were compared, taking into account measurement uncertainties; an added uncertainty was introduced to account for heterogeneity over the surfaces of the samples and between samples. All techniques gave large relative uncertainties for a low emissive and very specular material (polished aluminum), and results were quite scattered. All the indirect techniques by reflectance measurement gave results within ±0.01 for a high emissivity material. A commercial aluminum paint appears to be a good candidate for producing samples with medium level of emissivity
International Nuclear Information System (INIS)
Armstrong, Jonathan K.; Chowdhry, Babur Z.; Snowden, Martin J.; Dong, Jingfeng; Leharne, Stephen A.
2003-01-01
High sensitivity differential scanning calorimetry (HSDSC)--coupled with the application of a previously outlined thermodynamic model [Patterson et al., Langmuir 13 (1997) 2219]--has been used to the obtain thermodynamic parameters that characterise thermal aggregation in aqueous solutions of polyoxypropylene (POP) of molecular mass 1000 g mol -1 over a range of concentrations (2.5-51.5 g dm -3 ). An important aspect of the derived thermodynamic values, which complements previously reported HSDSC data [Armstrong et al., J. Phys. Chem. 99 (1995) 4590], is the elaboration of heat capacity changes which accompany the aggregation transition. The concentration dependence of the POP thermodynamic data, obtained in this investigation, has been established. These observations provide the means for establishing functional relationships between enthalpy and temperature as well as heat capacity and temperature. The parameters describing the quadratic relationship between enthalpy change associated with aggregation and temperature are in close agreement with those describing the linear relationship between heat capacity change and temperature
Structural and thermochemical properties of sodium magnesium phosphate glasses
Energy Technology Data Exchange (ETDEWEB)
Oueslati Omrani, Refka [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Kaoutar, Abdeltif; El Jazouli, Abdelaziz [LCMS, URAC 17, Faculté des Sciences Ben M’Sik, UH2MC, Casablanca (Morocco); Krimi, Saida [LPCMI, Faculté des Sciences Aïn Chok, UH2C, Casablanca (Morocco); Khattech, Ismail, E-mail: ismail.khattech@fst.rnu.tn [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Jemal, Mohamed [Université de Tunis El Manar, Faculté des Sciences de Tunis, Chemistry Department, LR01SE10 Applied Thermodynamics Laboratory, 2092 Tunis (Tunisia); Videau, Jean-Jacques [ICMCB, Institut de Chimie de la matière condensée, Université de Bordeaux 1 (France); Couzi, Michel [Institut des Sciences Moléculaires, CNRS-Université de Bordeaux 1 (France)
2015-05-25
Highlights: • Phosphate glasses were prepared by met quenching technique. • Structural study is investigated using FTIR, Raman and {sup 31}PNMR spectroscopy. • A 4.5% weight of H{sub 3}PO{sub 4} solution has use for glass dissolution. • Dissolution is endothermic for lower MgO content and becomes exothermic when x rises. - Abstract: Ternary phosphate based glasses with the general formula (50−x/2)Na{sub 2}O–xMgO–(50−x/2)P{sub 2}O{sub 5} (0 ⩽ x ⩽ 42.8 mol%), where the O/P ratio was varied from 3 to 3.75, have been prepared using a conventional melt quenching technique. Samples were investigated by means of density measurements, Fourier-transformed infrared (FTIR), Raman and {sup 31}P solid state magic angle spinning nuclear magnetic resonance (MAS-NMR) spectroscopies, differential scanning calorimetry (DSC), inductively coupled plasma atomic emission spectroscopy (ICP/AES) analysis and calorimetric dissolution. The depolymerization of metaphosphate chains are described by the decrease of Q{sup 2} tetrahedral sites allowing the formation of pyrophosphate groups (Q{sup 1}) revealed by spectroscopic investigations. As a result, the increase of density and glass transition temperature when x rises. Calorimetric study shows that the dissolution phenomenon is endothermic for a lower MgO content and becomes exothermic when magnesium oxide is gradually incorporated, suggesting the disruption of phosphate chains with increasing O/P ratio.
Energy Technology Data Exchange (ETDEWEB)
Mezosi, E.; Bajnok, L.; Sztojka, I.; Szabo, J.; Leovey, A.; Kakuk, G.; Nagy, E. [Department of Medicine, University Medical School, Debrecen (Hungary); Gyory, F. [Department of Surgery, University Medical School, Debrecen (Hungary); Varga, J.; Galuska, L. [Nuclear Medicine Centre, University Medical School, Debrecen (Hungary)
1999-08-01
Various diagnostic techniques have been successfully used in the clinical management of cold nodules; however, the decision on whether to employ surgery or a conservative treatment is not always easy. This study was designed to appraise the diagnostic value of technetium-99m methoxyisobutylisonitrile (MIBI) scintigraphy in the assessment of cold nodules detected using {sup 99m}Tc-pertechnetate. Fifty-two patients were included in the study. All had already been selected for surgery, based on their clinical and laboratory findings, including fine-needle aspiration biopsy. The total number of cold nodules on {sup 99m}Tc-pertechnetate scans was 59. The thyroid scan was performed 20-40 min after i.v. injection of 400 MBq of {sup 99m}Tc-MIBI. Uptake of MIBI in thyroid nodules was compared with that in the surrounding normal thyroid tissue, and a score of between 0 and 3 was assigned to each nodule as follows: 0, cold; 1, decreased; 2, equal; 3, hot. Definitive histology revealed nodular goitre in 24 cases, adenoma in 19, thyroiditis in 1, differentiated cancer in 12, medullary cancer in 2, and anaplastic cancer in 1. None of the degenerative nodules were hot on MIBI scan, while the adenomas showed a variety of MIBI imaging patterns, most frequently the score 3 pattern. In the diagnosis of differentiated thyroid cancer the sensitivities of score 3 and score 2+3 MIBI uptake patterns were 83% (10/12) and 100%, respectively. The score 3 MIBI uptake pattern had a specificity of 100% and a positive predictive value of 100% with respect to thyroid (benign and malignant) neoplastic diseases, whereas a specificity of 72% and a positive predictive value of 43% were observed in the detection of differentiated cancer. After a cold nodule had been detected using {sup 99m}Tc-pertechnetate, a second scan with high MIBI uptake increased by 7.8 times the probability that this nodule would be a differentiated cancer. In conclusion, {sup 99m}Tc-MIBI scintigraphy is a useful method in the
Analytical studies into radiation-induced starch damage in black and white peppers
International Nuclear Information System (INIS)
Sharif, M.M.; Farkas, J.
1993-01-01
Temperature dependence of the apparent viscosity of heat-generalized suspensions of untreated and irradiated pepper samples has been investigated. There was a close linear correlation between the logarithm of ''fluidity'' (reciprocal of the apparent viscosity) and the reciprocal absolute temperature of the measurement. The slope of the regression line (the temperature dependence of fluidity) increased with the radiation dose. Gelatinization thermograms of aqueous suspensions of ground pepper samples were obtained by differential scanning calorimetry. Temperature characteristics of heat-gelatinization endotherms showed no significant differences between untreated and irradiated samples. A calorimetric method for damaged starch, the estimation of reducing power, and the alcohol-induced turbidity of aqueous extracts showed statistically significant increases of starch damage at doses higher than 4 kGy. These indices of starch-depolymerization have been changed less dramatically by irradiation than the apparent viscosity of the heat-gelatinized suspensions. (author)
A comparative study on CdS: PEO and CdS: PMMA nanocomposite solid films
Energy Technology Data Exchange (ETDEWEB)
Padmaja, S. [Thin film centre, PSG College of Technology, Coimbatore (India); Jayakumar, S., E-mail: s_jayakumar_99@yahoo.com [Department of Physics, PSG Institute of Technology and Applied Research, Coimbatore (India); Balaji, R.; Vaideki, K. [Thin film centre, PSG College of Technology, Coimbatore (India)
2016-08-15
Cadmium Sulphide (CdS) nanoparticles were reinforced in Poly(ethylene Oxide) (PEO) and Poly(methyl methacrylate) (PMMA) matrices by in situ technique. The presence of CdS in PEO and PMMA matrix was confirmed using X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared spectroscopy (FTIR) analysis disclosed the co-ordination of CdS in the matrices. Thermal analysis of the nanocomposites was carried out using Differential Scanning calorimetric studies (DSC). The optical studies using UV–vis spectroscopy were carried out to find the band gap of the materials and the absorption onset. The CdS particle size in the matrices was found by Effective Mass Approximation (EMA) model using the band gap values and was confirmed by TEM studies. The surface trapped emissions of the nanocomposites were observed from the photoluminescence (PL) spectra. The distribution of CdS particles in the polymer matrices were presented by Atomic force microscopic studies (AFM).
Energy Technology Data Exchange (ETDEWEB)
Revesz, A.; Lendvai, J. [Eoetvoes Lorand Tudomanyegyeten, Budapest (Hungary). Dept. for General Physics; Cziraki, A. [Eoetvoes Univ. (Hungary). Dept. of Solid State Physics; Liebermann, H.H. [Honeywell Amorphous Metals, Morristown, NJ (United States); Bakonyi, I. [Hungarian Academy of Sciences (Hungary). Research Inst. for Solid State Physics and Optics
2001-05-01
Differential scanning calorimetry (DSC), powder diffraction and high-resolution X-ray diffraction (XRD), and transmission electron microscopy (TEM) investigations have been performed on melt-quenched amorphous Ni-P alloys with compositions of 18 to 22 at.% P. The calorimetric results revealed different crystallization routes during linear heating below, at and above the eutectic point (19 at.% P) but with the same general transformation scheme as reported previously for electrodeposited and electroless Ni-P amorphous alloys. The composition dependence of the activation energy of the crystallization and the heats evolved during the structural transformations were determined from DSC measurements. The average grain size was derived from XRD line broadening and important information on the crystallization products and their microstructure could be revealed also from the TEM studies. All these findings will have special significance when analysing the results of isothermal annealing experiments to be described in a forthcoming paper. (orig.)
International Nuclear Information System (INIS)
Al-Bachir, M.; Al-Adawi, M. A.; Hammouda, A.; Al-Baroudi, H.
2008-04-01
To investigate the effect of gamma irradiation on the solid state of ceftriaxon sodium salt (C18H16N8Na2O7S3) as a member of the third generation of cephalosporins. Solid Ceftriaxon as a pharmaceutical dosage was exposed to doses of 0, 5, 10, 15, 20, 25, and 50 kGy in 60 Co package irradiator. Physical and chemical characteristics of ceftriaxon have been investigated by using UV (Ultra Violet) and IR (Infra Red) spectroscopic, pH, solubility and DSC (Differential Scanning Calorimetric) methods. Antibacterial activity of ceftriaxon was investigated using Escherichia coli ATCC 25922 as a strain of bacteria. The obtained results indicated that gamma irradiation have no effect on physical and chemical characteristics of ceftriaxon, No significant differences were found between irradiated and non-irradiated samples in the Antibacterial activity of ceftriaxon on E. Coli.(author)
Physical ageing and molecular mobilities of sulfonated polysulfone for proton exchange membranes
Energy Technology Data Exchange (ETDEWEB)
Lixon Buquet, C. [LECAP EA 4528, Institute for Materials Research FED 4114, Universite de Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); PBS Department, UMR 6270 CNRS, MPBM, FR 3038, Universite de Rouen, Boulevard Maurice de Broglie, 76821 Mont Saint Aignan Cedex (France); Hamonic, F.; Saiter, A. [LECAP EA 4528, Institute for Materials Research FED 4114, Universite de Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); Dargent, E., E-mail: eric.dargent@univ-rouen.fr [LECAP EA 4528, Institute for Materials Research FED 4114, Universite de Rouen, Avenue de l' Universite BP 12, 76801 Saint Etienne du Rouvray (France); Langevin, D.; Nguyen, Q.T. [PBS Department, UMR 6270 CNRS, MPBM, FR 3038, Universite de Rouen, Boulevard Maurice de Broglie, 76821 Mont Saint Aignan Cedex (France)
2010-09-20
The thermal behaviour, the physical ageing and the amorphous phase dynamics of polysulfone (PSU) and sulfonated polysulfone (SPSU) are characterized by thermogravimetric analysis and temperature modulated differential scanning calorimetry. The sulfonic group introduction (the sulfonation degree is 70%) in the polymer implies a drastic decrease of the thermal decomposition temperature (220 and 517 {sup o}C for SPSU and PSU respectively) and a modification of calorimetric parameters (for SPSU, the heat capacity in the glassy state is lower and the glass transition temperature T{sub g} is higher than for PSU). In terms of molecular dynamics, the amorphous phase heterogeneities are greater and the cooperative rearranging region size at the glass transition temperature is smaller for SPSU than for PSU. Moreover, after a physical ageing process, the enthalpy recovery kinetic has slowed down by sulfonation. These results can be explained from the existence of sulfonic domains confining the amorphous phase domains.
A comparative study on CdS: PEO and CdS: PMMA nanocomposite solid films
International Nuclear Information System (INIS)
Padmaja, S.; Jayakumar, S.; Balaji, R.; Vaideki, K.
2016-01-01
Cadmium Sulphide (CdS) nanoparticles were reinforced in Poly(ethylene Oxide) (PEO) and Poly(methyl methacrylate) (PMMA) matrices by in situ technique. The presence of CdS in PEO and PMMA matrix was confirmed using X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared spectroscopy (FTIR) analysis disclosed the co-ordination of CdS in the matrices. Thermal analysis of the nanocomposites was carried out using Differential Scanning calorimetric studies (DSC). The optical studies using UV–vis spectroscopy were carried out to find the band gap of the materials and the absorption onset. The CdS particle size in the matrices was found by Effective Mass Approximation (EMA) model using the band gap values and was confirmed by TEM studies. The surface trapped emissions of the nanocomposites were observed from the photoluminescence (PL) spectra. The distribution of CdS particles in the polymer matrices were presented by Atomic force microscopic studies (AFM).
DEFF Research Database (Denmark)
Montes, Ruth; Lopez, David; Sot, Jesus
2008-01-01
Hot-cold hemolysis is the phenomenon whereby red blood cells, preincubated at 37 °C in the presence of certain agents, undergo rapid hemolysis when transferred to 4 °C. The mechanism of this phenomenon is not understood. PlcHR2, a phospholipase C/sphingomyelinase from Pseudomonas aeruginosa......) but also in goat erythrocytes, which lack PC. However, in horse erythrocytes, with a large proportion of PC and almost no SM, hot-cold hemolysis induced by PlcHR2 is not observed. Fluorescence microscopy observations confirm the formation of ceramide-enriched domains as a result of PlcHR2 activity. After......-cold hemolysis. Differential scanning calorimetry of erytrocyte membranes treated with PlcHR2 demonstrates the presence of ceramide-rich domains that are rigid at 4 °C but fluid at 37 °C. Ceramidase treatment causes the disapperance of the calorimetric signal assigned to ceramide-rich domains. Finally...
Waterborne hyperbranched alkyd-acrylic resin obtained by miniemulsion polymerization
Directory of Open Access Journals (Sweden)
Edwin Murillo
Full Text Available Abstract Four waterborne hyperbranched alkyd-acrylic resins (HBRAA were synthesized by miniemulsion polymerization from a hyperbranched alkyd resin (HBR, methyl methacrylate (MMA, butyl acrylate (BA and acrylic acid (AA, by using benzoyl peroxide (BPO and ammonium persulfate (AP as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC, nuclear magnetic resonance (NMR and gel permeation chromatography (GPC. The conversion percentage, glass transition temperature (Tg, content of acrylic polymer (determined by soxhlet extraction and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly monomodal. The film properties (gloss, flexibility, adhesion and drying time of the HBRAA were good.
Kamiya, Kazunobu; Suzuki, Noboru
2016-12-01
Some aluminium complexes are excellent catalysts of cationic polymerisation and are used for low-temperature and fast-curing adhesive, used in electronic part mounting. Microencapsulation is a suitable technique for getting high latency of the catalysts and long shelf life of the adhesives. For the higher latency in a cycloaliphatic epoxy compound, the microcapsule surface which retained small amount of aluminium complex was coated with epoxy polymer and the effect was examined. From the X-ray photoelectron spectroscopic results, the surface was recognised to be sufficiently coated and the differential scanning calorimetric analyses showed that the coating did not significantly affect the low-temperature and fast-curing properties of adhesive. After storing the mixture of cycloaliphatic epoxy compound, coated microcapsules, triphenylsilanol and silane coupling agent for 48 h at room temperature, the increase in viscosity was only 0.01 Pa s, resulting in the excellent shelf life.
Waterborne hyperbranched alkyd-acrylic resin obtained by mini emulsion polymerization
Energy Technology Data Exchange (ETDEWEB)
Murillo, Edwin, E-mail: edwinalbertomurillo@gmail.com [Grupo de Investigacion en Materiales Polimericos (GIMAPOL), Universidad Francisco de Paula Santander, San Jose de Cucuta (Colombia); Lopez, Betty [Grupo de Investigacion en Ciencia de los Materiales, Universidad de Antioquia, Calle, Medellin (Colombia)
2016-10-15
Four waterborne hyper branched alkyd-acrylic resins (HBRAA) were synthesized by mini emulsion polymerization from a hyper branched alkyd resin (HBR), methyl methacrylate (MMA), butyl acrylate (BA) and acrylic acid (AA), by using benzoyl peroxide (BPO) and ammonium persulfate (AP) as initiators. The reaction between HBR and acrylic monomers was evidenced by differential scanning calorimetric (DSC), nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The conversion percentage, glass transition temperature (T{sub g}), content of acrylic polymer (determined by soxhlet extraction) and molecular weight increased with the content of acrylic monomers used in the synthesis. The main structure formed during the synthesis was the HBRAA. The analysis by dynamic light scattering (DLS) showed that the particle size distribution of HBRAA2, HBRAA3 and HBRAA4 resins were mainly mono modal. The film properties (gloss, flexibility, adhesion and drying time) of the HBRAA were good. (author)
Laser shape setting of superelastic nitinol wires: Functional properties and microstructure
Tuissi, Ausonio; Coduri, Mauro; Biffi, Carlo Alberto
Shape setting is one of the most important steps in the production route of Nitinol Shape Memory Alloys (SMAs), as it can fix the functional properties, such as the shape memory effect and the superelasticity (SE). The conventional method for making the shape setting is performed at 400-500∘C in furnaces. In this work, a laser beam was adopted for performing straight shape setting on commercially available austenitic Nitinol thin wires. The laser beam, at different power levels, was moved along the wire length for inducing the functional performances. Calorimetric, pseudo-elastic and microstructural features of the laser annealed wires were studied through differential scanning calorimetry, tensile testing and high energy X-ray diffraction, respectively. It can be stated that the laser technology can induce SE in thin Nitinol wires: the wire performances can be modulated in function of the laser power and improved functional properties can be obtained.
Energy Technology Data Exchange (ETDEWEB)
Al Lafi, Abdul G. [Department of Chemistry, Atomic Energy Commission, Damascus, P.O. Box 6091 (Syrian Arab Republic); Hay, James N., E-mail: cscientific9@aec.org.sy [The School of Metallurgy and Materials, College of Physical Sciences and Engineering, University of Birmingham, Edgbaston, Birmingham B15 2TT (United Kingdom)
2015-07-20
Highlights: • 2D-DSC mapping was applied to analyze the heat flow responses of hydrated crosslinked sPEEK. • Two types of loosely bond water were observed. • The first was bond to the sulfonic acid groups and increased with ion exchange capacity. • The second was attributed to the polar groups introduced by ions irradiation and increased with crosslinking degree. • DSC combined with 2D mapping provides a powerful tool for polymer structural determination. - Abstract: This paper reports the first application of two-dimensional differential scanning calorimetry correlation mapping, 2D-DSC-CM to analyze the heat flow responses of sulphonated poly(ether ether ketone), sPEEK, films having different ion exchange capacity and degrees of crosslinks. With the help of high resolution and high sensitivity of 2D-DSC-CM, it was possible to locate two types of loosely bound water within the structure of crosslinked sPEEK. The first was bound to the sulfonic acid groups and dependent on the ion exchange capacity of the sPEEK. The second was bound to other polar groups, either introduced by irradiation with ions and dependent on the crosslinking degree or present in the polymer such as the carbonyl groups or terminal units. The results suggest that the ability of the sulfonic acid groups in the crosslinked sPEEK membranes to adsorb water molecules is increased by crosslinking, probably due to the better close packing efficiency of the crosslinked samples. DSC combined with 2D correlation mapping provides a fast and powerful tool for polymer structural determination.
Barwart, O; Rollinger, J M; Burger, A
1999-10-01
Differential scanning calorimetry (DSC) was used to determine the transition temperature ranges (TTR) of four types of super-elastic orthodontic nickel-titanium coil springs (Sentalloy). A knowledge of the TTR provides information on the temperature at which a NiTi wire or spring can assume superelastic properties and when this quality disappears. The spring types in this study can be distinguished from each other by their characteristic TTR during cooling and heating. For each tested spring type a characteristic TTR during heating (austenite transformation) and cooling (martensite transformation) was evaluated. The hysteresis of the transition temperature, found between cooling and heating, was 3.4-5.2 K. Depending on the spring type the austenite transformation started (As) at 9.7-17.1 degrees C and finished (Af) at 29.2-37 degrees C. The martensite transformation starting temperature (Ms) was evaluated at 32.6-25.4 degrees C, while Mf (martensite transformation finishing temperature) was 12.7-6.5 degrees C. The results show that the springs become super-elastic when the temperature increases and As is reached. They undergo a loss of super-elastic properties and a rapid decrease in force delivery when they are cooled to Mf. For the tested springs, Mf and As were found to be below room temperature. Thus, at room temperature and some degrees lower, all the tested springs exert super-elastic properties. For orthodontic treatment this means the maintenance of super-elastic behaviour, even when mouth temperature decreases to about room temperature as can occur, for example, during meals.
Indurthi, Venkata S K; Leclerc, Estelle; Vetter, Stefan W
2014-08-01
Glycation alters the drug binding properties of serum proteins and could affect free drug concentrations in diabetic patients with elevated glycation levels. We investigated the effect of bovine serum albumin glycation by eight physiologically relevant glycation reagents (glucose, ribose, carboxymethyllysine, acetoin, methylglyoxal, glyceraldehyde, diacetyl and glycolaldehyde) on diclofenac drug binding. We used this non-steroidal anti-inflammatory drug diclofenac as a paradigm for acidic drugs with high serum binding and because of its potential cardiovascular risks in diabetic patients. Isothermal titration calorimetry showed that glycation reduced the binding affinity Ka of serum albumin and diclofenac 2 to 6-fold by reducing structural rigidity of albumin. Glycation affected the number of drug binding sites in a glycation reagent dependent manner and lead to a 25% decrease for most reagent, expect for ribose, with decreased by 60% and for the CML-modification, increased the number of binding sites by 60%. Using isothermal titration calorimetry and differential scanning calorimetry we derived the complete thermodynamic characterization of diclofenac binding to all glycated BSA samples. Our results suggest that glycation in diabetic patients could significantly alter the pharmacokinetics of the widely used over-the-counter NSDAI drug diclofenac and with possibly negative implications for patients. Copyright © 2014 Elsevier B.V. All rights reserved.
Clinical research of bone scan characteristics for metabolic bone diseases
International Nuclear Information System (INIS)
Zhu Ruisen; Luo Qiong; Lu Haikui; Chen Libo; Luo Quanyong
2009-01-01
Characteristic images of 99m Tc-MDP bone scintigraphy in patients with metabolic bone diseases (MBD) were analyzed and compared, in an attempt to improve the capability of differential diagnosis in this aspect. A total of 142 cases, clinically confirmed as (MBD), were categorized into six groups: hyperparathyroidism (117), renal osteodystrophy (4), Paget's disease (16), hypophosphatemic osteomalacia (2), Albers-Schonberg disease (2), and Brittle bone disease (1). They were diagnosed clinically or pathologically, and scanned with 99m Tc-MDP bone scintegraphy, from which the 142 MBD cases were classified into 4 types. The cases of Type I had increased amount of 99m Tc-MDP uptake in whole body bones, including hyperparathyroidism, Albers-Schonberg disease, brittle bone disease and renal osteodystrophy. The cases of Type II had high uptake of 99m Tc-MDP in local region of bones, including paget's disease, hypophosphatemic osteomalacia and hyperparathyroidism. A Type I case with pathological fracture or secondary osteopathy was classified as Type III. Type IV cases were in early stage of hyperparathyroidism, with normal bone scan image. Analysis of the characteristics of 99m Tc-MDP bone scintigraphic findings (locations, morphology and intensities) in patients with MBD may be helpful in the differential diagnosis of MBD, in association with the patient's history and X-ray data altogether. (authors)