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High Pressure (high + pressure)
Kinds of High Pressure Terms modified by High Pressure Selected AbstractsEFFECT OF HIGH PRESSURE ON LACTOCOCCAL BACTERIOPHAGESJOURNAL OF FOOD SAFETY, Issue 1 2009M. DILEK ABSTRACT Four different host-specific lactococcal bacteriophages were subjected to high hydrostatic pressure and heat treatments. Pressure treatments were done at room temperature at 300 and 350 MPa for 5,40 min. Complete inactivation of bacteriophages was observed starting at 350 MPa for 20-min treatment at room temperature. The effect of heat on the bacteriophages was analyzed by heat treatment at 71.7C for predetermined lengths of time (1,5 min). Decrease in bacteriophage number was observed after 3 min of heat treatment at 71.7C. Pressure treatment at 350 MPa/5 min and heat treatment at 71.7C/3 min were both found to be effective for the inactivation of lactococcal bacteriophages. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis indicated that protein profiles of pressure-treated (350 MPa, 25 min) bacteriophages were altered. PRACTICAL APPLICATIONS Bacteriophages are still a problem for the production of fermented dairy products, as there has not been a process to eliminate them completely from the fermentation environment. Processes such as pasteurization are not adequate to eliminate bacteriophages. However, new food preservation methods have been developed, one of which is high hydrostatic pressure (HHP) processing. HHP has potential application for the inactivation of viruses. Here, we demonstrate the application of HHP to inactivate the bacteriophages of dairy starter culture Lactococcus in comparison with heat treatment. [source] Characteristics of VHF H2 Plasma Produced at High PressureCONTRIBUTIONS TO PLASMA PHYSICS, Issue 4 2008Y. Yamauchi Abstract A VHF H2 plasma was produced with the multi rod electrode at high pressure and the plasma parameters were measured as a function of pressure for different VHF powers at 60 MHz. It was found that when the pressure is increased, the ion saturation current peaks at certain pressure and finally decreases at high pressures, while the electron temperature is around 10 eV. The wall potential at high pressure was lower than the values estimated from the electron temperature using the probe theory. Furthermore, the anomalous reduction of the electron saturation current was observed. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] An Individual Carbon Nanotube Transistor Tuned by High PressureADVANCED FUNCTIONAL MATERIALS, Issue 19 2010Christophe Caillier Abstract A transistor based on an individual multiwalled carbon nanotube is studied under high-pressure up to 1 GPa. Dramatic effects are observed, such as the lowering of the Schottky barrier at the gold,nanotube contacts, the enhancement of the intertube conductance, including a discontinuity related to a structural transition, and the decrease of the gate hysteresis of the device. [source] Onion Cells After High Pressure and Thermal Processing: Comparison of Membrane Integrity Changes Using Different Analytical Methods and Impact on Tissue TextureJOURNAL OF FOOD SCIENCE, Issue 7 2010Maria E. Gonzalez Abstract:, Two different analytical methods were evaluated for their capacity to provide quantitative information on onion cell membrane permeability and integrity after high pressure and thermal processing and to study the impact of these processing treatments on cell compartmentalization and texture quality. To determine changes in cell membrane permeability and/or integrity the methodologies utilized were: (1) measurement of a biochemical product, pyruvate, formed as a result of membrane permeabilization followed by enzymatic activity and (2) leakage of electrolytes into solution. These results were compared to previously determined methods that quantified cell viability and 1H-NMR T2 of onions. These methods allowed for the monitoring of changes in the plasma and tonoplast membranes after high pressure or thermal processing. High pressure treatments consisted of 5 min holding times at 50, 100, 200, 300, or 600 MPa. Thermal treatments consisted of 30 min water bath exposure to 40, 50, 60, 70, or 90 °C. There was strong agreement between the methods in the determination of the ranges of high pressure and temperature that induce changes in the integrity of the plasma and tonoplast membranes. Membrane rupture could clearly be identified at 300 MPa and above in high pressure treatments and at 60 °C and above in the thermal treatments. Membrane destabilization effects could already be visualized following the 200 MPa and 50 °C treatments. The texture of onions was influenced by the state of the membranes and was abruptly modified once membrane integrity was lost. Practical Application:, In this study, we used chemical, biochemical, and histological techniques to obtain information on cell membrane permeability and onion tissue integrity after high pressure and thermal processing. Because there was strong agreement between the various methods used, it is possible to implement something relatively simple, such as ion leakage, into routine quality assurance measurements to determine the severity of preservation methods and the shelf life of processed vegetables. [source] Effects of High Pressure on Texture and Microstructure of Sea Bass (Dicentrarchus labrax L.) FilletsJOURNAL OF FOOD SCIENCE, Issue 8 2005Romuald Chéret ABSTRACT High pressure is an innovative non-thermal food-preservation technology. We studied the effect of high-pressure treatment up to 500 MPa for 5 min on physical characteristics of sea bass fillets after 0, 7, and 14 d of refrigerated storage. Color results exhibited an increase of lightness and a slight change of hue, which might be imperceptible in cooked fish. High-pressure treatment induced a decrease of exudation and water-holding capacity. Pressure treatment above 300 MPa provoked higher fish hardness after storage than in untreated sample, proving the ability of high pressure to improve textural quality of chilled, stored fish fillet. These assessments were corroborated with microstructure observations. We showed that high-pressure treatment at 500 MPa allowed, after 7 d of storage, a total aerobic count equivalent to that of untreated fresh fish fillet to be obtained. Thus, high pressure might be considered to be a technology able to improve safety and textural quality of fresh fish fillets. [source] Impact of Supercritical Carbon Dioxide and High Pressure on Lipoxygenase and Peroxidase ActivityJOURNAL OF FOOD SCIENCE, Issue 8 2000W. TEDJO ABSTRACT: The effects of supercritical carbon dioxide (ScCO2) treatment and high hydrostatic pressure treatment on the activities of lipoxygenase (LOX) and peroxidase (POD) were studied. Hydrostatic pressure treatment (240 MPa, 55 °C, 15 min) of LOX and POD in 30% sucrose solutions without buffer led to approximately 80% and approximately 50% residual activity, respectively. Application of ScCO2 (35.2 MPa, 40 °C, 15 min for LOX and 62.1 MPa, 55 °C, 15 min for POD) achieved approximately 35% LOX and approximately 65% POD inactivity in 30 % sucrose solutions. Total inactivation of LOX (10.3 MPa, 50 °C and 15 min) and of POD (62.1 MPa, 55 °C and 15 min) could be achieved through ScCO2 treatment of unbuffered solution. Increasing the concentration of sucrose and buffering (pH range 4 to 9) of enzyme solutions resulted in increased resistance of the enzymes to ScCO2 treatment. [source] Crystal Structure and Compressibility of Pb(Zr1,xTix)O3 Ceramics Under High PressureJOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 6 2010Young Ho Ko X-ray diffraction patterns of Pb(Zr0.3Ti0.7)O3 and Pb(Zr0.7Ti0.3) O3 have been measured at pressures up to 36 GPa with good signal-to-noise ratio using synchrotron radiation. In order to refine the crystal structure, Rietveld analysis has been performed. The structure of Pb(Zr0.3Ti0.7)O3 is tetragonal in space group P4mm with lattice parameters a=b=3.9843±0.0003 Å and c= 4.1545±0.0003 Å at ambient pressure. A pressure-induced phase transition was found in the pressure range higher than ,7.4 GPa at room temperature. The high-pressure phase is cubic in space groupwith lattice parameter a=3.9600±0.0003 Å at 7.4 GPa. The Birch,Murnaghan equation of state fit to the experimental data yields B0=83.9±1.7 GPa (B,0=4.0 is fixed) for tetragonal phase and B0=102.5±4.4 GPa (B,0=4.0 is fixed) for cubic phase with V0=65.95±0.01 Å3. The structure of Pb(Zr0.7Ti0.3)O3 is monoclinic in space group Cc with lattice parameters a=10.0627±0.0164 Å, b=5.8511±0.0024 Å, c= 5.7949±0.0020 Å, and ,=125.185±0.119 ° at ambient pressure. No pressure-induced phase transition for Pb(Zr0.7Ti0.3)O3 was observed over the pressure range of this study. The Birch,Murnaghan equation of state fit to the experimental data yields B0=73.6±18.9 GPa (B,0=4.0 is fixed) with V0= 278.81±0.63 Å3. [source] Melt Crystallization and Morphology of Poly(p -phenylene sulfide) under High PressureMACROMOLECULAR CHEMISTRY AND PHYSICS, Issue 4 2007Jun Lu Abstract The high-pressure melt-crystallization behaviors of poly(p -phenylene sulfide) (PPS) were investigated using WAXD, DSC, TEM and SEM. PPS extended-chain crystals with c -axis thickness exceeding 4.5 µm were formed at high pressure. The DSC results showed that the melting temperature and melting enthalpy of high-pressure crystallized PPS samples were up to 327.53,°C and 94.96 J,·,g,1, respectively, which were higher than the values of ideal PPS perfect crystals used by some researchers, and the melting enthalpy of the samples fluctuated regularly during the thickening growth of the PPS crystals. Other characteristic morphologies obtained at high pressure, i.e. spherulites and rod-like crystals, were also presented with the SEM measurements. [source] Liver Transplantation Using Liver Grafts Preserved Under High PressureARTIFICIAL ORGANS, Issue 10 2005Takuya Ueno Abstract: To extend organ preservation time, we attempted to establish a unique method of maintaining a preservation solution in a stable unfrozen state below its freezing point by pressurizing the solution. Livers removed from Lewis rats (RT1l) were stored in UW solution pressurized at the prescribed pressure. After the termination of preservation, orthotopic liver transplantation was performed. Experiment 1: Liver grafts were pressurized up to 30, 40, 50, and 70 MPa and preserved at 0°C for 60 min. Experiment 2: Liver grafts were compressed at a rate of 1.32 or 0.04 MPa/s to 35 MPa and preserved for 60 min at 0°C. Experiments 3 and 4: Liver grafts were pressurized up to 5, 10, 20, and 30 MPa and preserved at ,2°C (Exp. 3), ,3°C or ,4°C (Exp. 4) for 5 h. All rats transplanted with livers pressurized up to 30 MPa (Exp. 1), all rats in the 5 MPa and control groups at ,2°C (Exp. 3), and all rats in the 5 MPa group at ,3°C (Exp. 4) survived for 2 weeks. In light microscopy, diffuse hemorrhage and vacuolar degeneration of hepatocytes were observed in a pressure-dependent manner. Liver grafts preserved under pressurized, subzero nonfrozen condition have sufficient function to sustain the life of rats after orthotopic transplantation. [source] Density Measurements of Fluids and Their Mixtures at High PressureCHEMICAL ENGINEERING & TECHNOLOGY (CET), Issue 6 2007A. M. F. Palavra Abstract The principles of the isochoric method are described, as well as the different variants of this method that can be considered according to the technique used to determine the amount of fluid inside the high pressure cell. An automated isochoric apparatus to measure the density of binary mixtures is presented. Accurate isochoric measurements of density of pure fluids, involving molecules like methanol, and mixtures, such as nitrogen plus methane and a multicomponent system with a composition representative of the U.S.A. commercial Gulf Coast natural gas, are analyzed. Moreover, the effect of the thermal degradation of fluids at high temperatures on the accuracy of the density measurements is also discussed. [source] ChemInform Abstract: Organocatalytic Asymmetric Diels,Alder Reaction of Furan under High Pressure.CHEMINFORM, Issue 34 2010Akiko Mimoto Abstract The combined use of high pressure and organocatalysis promotes the title reaction. [source] ChemInform Abstract: Phase Diagram of the La,Si Binary System under High Pressure and the Structures of Superconducting LaSi5 and LaSi10.CHEMINFORM, Issue 45 2009Shoji Yamanaka Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: High Pressure Assisted Synthesis of 1,2,3-Trialkyldiaziridines from N-Chloroalkylamines.CHEMINFORM, Issue 30 2008Vladimir V. Kuznetsov Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: Chiral N-Allylpyrroles as Versatile Substrates under Rhodium-Catalyzed Hydroformylation: Good Regio- and Diastereoselectivity at Room Temperature and High Pressure.CHEMINFORM, Issue 9 2008Roberta Settambolo Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Possible Existence of Alkali Metal Orthocarbonates at High Pressure.CHEMINFORM, Issue 46 2007Jeljko P. Cancarevic Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Revisiting the Sr,Cr(IV),O System at High Pressure and Temperature with Special Reference to Sr3Cr2O7.CHEMINFORM, Issue 44 2007Elizabeth Castillo-Martinez Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract, please click on HTML or PDF. [source] Multicomponent Strecker Reaction under High Pressure.CHEMINFORM, Issue 46 2005Kiyoshi Matsumoto Abstract For Abstract see ChemInform Abstract in Full Text. [source] Multicomponent Strecker Reaction under High Pressure.CHEMINFORM, Issue 46 2005Kiyoshi Matsumoto Abstract For Abstract see ChemInform Abstract in Full Text. [source] Diels,Alder Cycloadditions of Functionalized (Z)-1-Benzylidene-2-methylene Cyclohexanes: The Beneficial Effect of High Pressure.CHEMINFORM, Issue 30 2004Thierry Lomberget Abstract For Abstract see ChemInform Abstract in Full Text. [source] Structure of Silicate Glasses and Melts at High Pressure: Quantum Chemical Calculations and Solid-State NMR.CHEMINFORM, Issue 28 2004Sung Keun Lee No abstract is available for this article. [source] ChemInform Abstract: Stabilization of CuIII under High Pressure in Sr2CuGaO5.CHEMINFORM, Issue 32 2002M. L. Ruiz-Gonzalez Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] ChemInform Abstract: TIF and PbO under High Pressure: Unexpected Persistence of the Stereochemically Active Electron Pair.CHEMINFORM, Issue 16 2002Ulrich Haeussermann Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Dimerization of CO2 at High Pressure and TemperatureCHEMPHYSCHEM, Issue 9 2005Francesco Tassone Dr. Two,s company: Constant-pressure ab initio molecular dynamics simulations reveal the reaction of two CO2 molecules to form the metastable C2O4 species (see picture) in high-temperature (4000 K) and high-pressure (,20 GPa) liquid CO2. The dimer exhibits a unique Raman-active vibrational mode, which is characteristic for this molecule and consistent with experimental observations. [source] Electrochemistry at High Pressures: A ReviewELECTROANALYSIS, Issue 10 2004Debora Giovanelli Abstract High pressure electrochemical studies are potentially dangerous and less immediately implemented than conventional investigations. Technical obstacles related to properties of the working electrode material, preparation of its surface, availability of suitable reference electrodes, and the need for specially designed high pressure equipment and cells may account for the relative lack of experimental data on electrochemistry at high pressures. However, despite the stringent requirements for system and equipment stability, significant developments have been made in recent years and the combination of electrochemical methods with high hydrostatic pressure has provided useful insights into the thermodynamics, kinetics, and other physico-chemical characteristics of a wide range of redox reactions. In addition to fundamental information, high pressure electrochemistry has also lead to a better understanding of a variety of processes under non-classical conditions with potential applications in today's industrial environment from extraction and electrosynthesis in supercritical fluids to measurement of the pH at the bottom of the ocean. The purpose of this article is to detail the experimental pressurizing apparatus for electroanalytical measurements at high pressures and to review the relevant literature on the effect of pressure on electrode processes and on the properties of aqueous electrolyte solutions. [source] WS2 and MoS2 Inorganic Fullerenes,Super Shock Absorbers at Very High Pressures,ADVANCED MATERIALS, Issue 12 2005Q. Zhu Superb antishock WS2 inorganic fullerenes (IF) can sustain shock pressures up to 25,GPa, suggesting that these IFs are probably the toughest cage molecules known. The Figure shows images of a) pre- and b) post-shock WS2 IF nanoparticles. These IFs may have great potential to withstand very high applied loads when used as solid-state lubricants. [source] A Novel Device for Single Particle Light Scattering Size Analysis and Concentration Measurement at High Pressures and TemperaturesPARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 2 2008Heinz Umhauer Abstract Based on the findings of previous work, a novel instrument was developed for the size analysis and concentration measurement of particles dispersed in gases at high temperatures (600,°C) and pressures (16 bar). The main motivation for the construction of this device was a measurement requirement at the conditions of a pressurized pulverized coal combustion (PPCC) test installation in Dorsten, Germany. The development of a high efficiency (>,50,%), coal based, combined cycle process, and specifically, the development of efficient gas cleaning technology for gas combustion under demanding conditions (1400,°C and 16 bar) was the main target. A suitable measurement technique was required for the determination of particle size and concentration downstream of the gas cleaning equipment, which is able to operate close to the given conditions. The performance of the novel device was tested in several measurement series with various monodisperse aerosols at ambient conditions as well as in high pressure, high temperature situations with very satisfactory results, i.e., the lower detection limit (50,% counting efficiency at ca. 0.3 ,m) and resolution of the novel device are comparable to state of the art instruments (of the same principle) intended for room temperature operation. [source] ChemInform Abstract: Density Functional Calculation of Band-Parameters for Boron Nitride at Normal and High Pressures.CHEMINFORM, Issue 10 2008S. Saib Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 200 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Cardiopulmonary, blood and peritoneal fluid alterations associated with abdominal insufflation of carbon dioxide in standing horsesEQUINE VETERINARY JOURNAL, Issue 3 2003F. G. LATIMER Summary Reasons for performing study: Abdominal insufflation is performed routinely during laparoscopy in horses to improve visualisation and facilitate instrument and visceral manipulations during surgery. It has been shown that high-pressure pneumoperitoneum with carbon dioxide (CO2) has deleterious cardiopulmonary effects in dorsally recumbent, mechanically ventilated, halothane-anaesthetised horses. There is no information on the effects of CO2 pneumoperitoneum on cardiopulmonary function and haematology, plasma chemistry and peritoneal fluid (PF) variables in standing sedated horses during laparoscopic surgery. Objectives: To determine the effects of high pressure CO2 pneumoperitoneum in standing sedated horses on cardiopulmonary function, blood gas, haematology, plasma chemistry and PF variables. Methods: Six healthy, mature horses were sedated with an i.v. bolus of detomidine (0.02 mg/kg bwt) and butorphanol (0.02 mg/kg bwt) and instrumented to determine the changes in cardiopulmonary function, haematology, serum chemistry and PF values during and after pneumoperitoneum with CO2 to 15 mmHg pressure for standing laparoscopy. Each horse was assigned at random to either a standing left flank exploratory laparoscopy (LFL) with CO2 pneumoperitoneum or sham procedure (SLFL) without insufflation, and instrumented for measurement of cardiopulmonary variables. Each horse underwent a second procedure in crossover fashion one month later so that all 6 horses had both an LFL and SLFL performed. Cardiopulmonary variables and blood gas analyses were obtained 5 mins after sedation and every 15 mins during 60 mins baseline (BL), insufflation (15 mmHg) and desufflation. Haematology, serum chemistry analysis and PF analysis were performed at BL, insufflation and desufflation, and 24 h after the conclusion of each procedure. Results: Significant decreases in heart rate, cardiac output and cardiac index and significant increases in mean right atrial pressure, systemic vascular resistance and pulmonary vascular resistance were recorded immediately after and during sedation in both groups of horses. Pneumoperitoneum with CO2 at 15 mmHg had no significant effect on cardiopulmonary function during surgery. There were no significant differences in blood gas, haematology or plasma chemistry values within or between groups at any time interval during the study. There was a significant increase in the PF total nucleated cell count 24 h following LFL compared to baseline values for LFL or SLFL at 24 h. There were no differences in PF protein concentrations within or between groups at any time interval. Conclusions: Pneumoperitoneum with CO2 during standing laparoscopy in healthy horses does not cause adverse alterations in cardiopulmonary, haematology or plasma chemistry variables, but does induce a mild inflammatory response within the peritoneal cavity. Potential relevance: High pressure (15 mmHg) pneumoperitoneum in standing sedated mature horses for laparoscopic surgery can be performed safely without any short-term or cumulative adverse effects on haemodynamic or cardiopulmonary function. [source] Effects of High Pressure on Texture and Microstructure of Sea Bass (Dicentrarchus labrax L.) FilletsJOURNAL OF FOOD SCIENCE, Issue 8 2005Romuald Chéret ABSTRACT High pressure is an innovative non-thermal food-preservation technology. We studied the effect of high-pressure treatment up to 500 MPa for 5 min on physical characteristics of sea bass fillets after 0, 7, and 14 d of refrigerated storage. Color results exhibited an increase of lightness and a slight change of hue, which might be imperceptible in cooked fish. High-pressure treatment induced a decrease of exudation and water-holding capacity. Pressure treatment above 300 MPa provoked higher fish hardness after storage than in untreated sample, proving the ability of high pressure to improve textural quality of chilled, stored fish fillet. These assessments were corroborated with microstructure observations. We showed that high-pressure treatment at 500 MPa allowed, after 7 d of storage, a total aerobic count equivalent to that of untreated fresh fish fillet to be obtained. Thus, high pressure might be considered to be a technology able to improve safety and textural quality of fresh fish fillets. [source] Prediction of ice content in biological model solutions when frozen under high pressureBIOTECHNOLOGY PROGRESS, Issue 2 2009B. Guignon Abstract High pressure is, at least, as effective as cryoprotective agents (CPAs) and are used for decreasing both homogenous nucleation and freezing temperatures. This fact gives rise to a great variety of possible cryopreservation processes under high pressure. They have not been optimized yet, since they are relatively recent and are mainly based on the pressure,temperature phase diagram of pure water. Very few phase diagrams of biological material are available under pressure. This is owing to the lack of suitable equipment and to the difficulties encountered in carrying out the measurements. Different aqueous solutions of salt and CPAs as biological models are studied in the range of 0°C down to -35°C, 0.1 up to 250 MPa, and 0,20% w/w total solute concentration. The phase transition curves of glycerol and of sodium chloride with either glycerol or sucrose in aqueous solutions are determined in a high hydrostatic pressure vessel. The experimental phase diagrams of binary solutions were well described by a third-degree polynomial equation. It was also shown that Robinson and Stokes' equation at high pressure succeeds in predicting the phase diagrams of both binary and ternary solutions. The solute cryoconcentration and the ice content were calculated as a function of temperature and pressure conditions during the freezing of a binary solution. This information should provide a basis upon which high-pressure cryopreservation processes may be performed and the damages derived from ice formation evaluated. © 2009 American Institute of Chemical Engineers Biotechnol. Prog., 2009 [source] |