The Experts below are selected from a list of 270 Experts worldwide ranked by ideXlab platform
Eric T Kool - One of the best experts on this subject based on the ideXlab platform.
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Efficient Isothermal Expansion of human telomeric and minisatellite repeats by Thermococcus litoralis DNA polymerase
Nucleic acids research, 2005Co-Authors: Jorg S Hartig, Eric T KoolAbstract:Repeating DNA sequences, such as telomeres, centromeres, and micro- and mini-satellites, comprise 50% of the genome and play important roles in regulatory and pathogenic mechanisms. In order to study structures and functions of such repeating sequences, it is important to have simple and efficient methods for making them in vitro. Here, we describe the efficient and convenient Expansion of repetitive telomeric and minisatellite DNA sequences starting from small synthetic templates to final product lengths of several hundreds to thousands of nucleotides by the thermostable DNA polymerase from Thermococcus litoralis (Vent DNA polymerase). This enzyme was so far unknown to catalyze repeat Expansion. Either single-stranded or double-stranded DNAs could be produced, depending on nucleotides present. Compared to earlier results obtained with other enzymes, the Expansion reaction is highly efficient both in its yield and product length, and proceeds without thermal cycling. Moreover, the products are characterized by a narrow length distribution.
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efficient Isothermal Expansion of human telomeric and minisatellite repeats by thermococcus litoralis dna polymerase
Nucleic Acids Research, 2005Co-Authors: Jorg S Hartig, Eric T KoolAbstract:Repeating DNA sequences, such as telomeres, centromeres, and micro- and mini-satellites, comprise 50% of the genome and play important roles in regulatory and pathogenic mechanisms. In order to study structures and functions of such repeating sequences, it is important to have simple and efficient methods for making them in vitro. Here, we describe the efficient and convenient Expansion of repetitive telomeric and minisatellite DNA sequences starting from small synthetic templates to final product lengths of several hundreds to thousands of nucleotides by the thermostable DNA polymerase from Thermococcus litoralis (Vent DNA polymerase). This enzyme was so far unknown to catalyze repeat Expansion. Either single-stranded or double-stranded DNAs could be produced, depending on nucleotides present. Compared to earlier results obtained with other enzymes, the Expansion reaction is highly efficient both in its yield and product length, and proceeds without thermal cycling. Moreover, the products are characterized by a narrow length distribution.
Jorg S Hartig - One of the best experts on this subject based on the ideXlab platform.
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Efficient Isothermal Expansion of human telomeric and minisatellite repeats by Thermococcus litoralis DNA polymerase
Nucleic acids research, 2005Co-Authors: Jorg S Hartig, Eric T KoolAbstract:Repeating DNA sequences, such as telomeres, centromeres, and micro- and mini-satellites, comprise 50% of the genome and play important roles in regulatory and pathogenic mechanisms. In order to study structures and functions of such repeating sequences, it is important to have simple and efficient methods for making them in vitro. Here, we describe the efficient and convenient Expansion of repetitive telomeric and minisatellite DNA sequences starting from small synthetic templates to final product lengths of several hundreds to thousands of nucleotides by the thermostable DNA polymerase from Thermococcus litoralis (Vent DNA polymerase). This enzyme was so far unknown to catalyze repeat Expansion. Either single-stranded or double-stranded DNAs could be produced, depending on nucleotides present. Compared to earlier results obtained with other enzymes, the Expansion reaction is highly efficient both in its yield and product length, and proceeds without thermal cycling. Moreover, the products are characterized by a narrow length distribution.
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efficient Isothermal Expansion of human telomeric and minisatellite repeats by thermococcus litoralis dna polymerase
Nucleic Acids Research, 2005Co-Authors: Jorg S Hartig, Eric T KoolAbstract:Repeating DNA sequences, such as telomeres, centromeres, and micro- and mini-satellites, comprise 50% of the genome and play important roles in regulatory and pathogenic mechanisms. In order to study structures and functions of such repeating sequences, it is important to have simple and efficient methods for making them in vitro. Here, we describe the efficient and convenient Expansion of repetitive telomeric and minisatellite DNA sequences starting from small synthetic templates to final product lengths of several hundreds to thousands of nucleotides by the thermostable DNA polymerase from Thermococcus litoralis (Vent DNA polymerase). This enzyme was so far unknown to catalyze repeat Expansion. Either single-stranded or double-stranded DNAs could be produced, depending on nucleotides present. Compared to earlier results obtained with other enzymes, the Expansion reaction is highly efficient both in its yield and product length, and proceeds without thermal cycling. Moreover, the products are characterized by a narrow length distribution.
Giuseppe Spazzafumo - One of the best experts on this subject based on the ideXlab platform.
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Parametric analysis of a steam cycle with a quasi-Isothermal Expansion
International Journal of Hydrogen Energy, 2001Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Alessandra Perna, Giuseppe SpazzafumoAbstract:Using a hydrogen/oxygen steam generator it is possible to carry out many steam mixing re-heatings without increasing the complexity of a traditional steam power-plant: steam is not required to re-enter the boiler for each re-heating. An Isothermal Expansion could thus be approached by means of several adiabatic Expansions and several steam mixing re-heatings. A theoretical investigation showed that an Isothermal Expansion could achieve high efficiency (up to 70% of HHV) when the waste heat at the turbine outlet is recovered for pre-heating water, hydrogen and oxygen. In a real plant the number of re-heatings that can be carried out, although high, is limited and we can therefore expect an efficiency drop which varies as a function of the number of re-heatings, the re-heating temperature and the maximum pressure. In order to evaluate real cycle performance, a numerical code, specifically created, was implemented.
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A steam cycle with an Isothermal Expansion: the effect of flowvariation
International Journal of Hydrogen Energy, 1999Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Alessandra Perna, Giuseppe SpazzafumoAbstract:Abstract In the present paper the steam cycle proposed by Spazzafumo has been again taken into consideration and the effectof the flow variation on the cycle performances has been investigated. The Isothermal Expansion with increasingflow causes a decrease in cycle efficiency due to the greater condenser losses and, at high superheated temperatures,to the impossibility of full recovering of the available heat at the end of the Expansion. However, using part of thisheat for preheating the required hydrogen and oxygen, yields a significant increase in efficiency. © 1999International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.
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A STEAM CYCLE WITH DIRECT COMBUSTION OF HYDROGEN AND OXYGEN AND AN Isothermal Expansion
Hydrogen Power: Theoretical and Engineering Solutions, 1998Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Alessandra Perna, Giuseppe SpazzafumoAbstract:A new thermodynamical cycle characterised from an Isothermal Expansion has been examined from a theoretical point of view. In the real cycle the Isothermal Expansion could be approached by means of mixing re-heatings. The high temperature steam for mixing is produced in a direct steam generator burning a stoichiometric mixture of hydrogen and oxygen. The theoretical analysis has shown that the reference cycle allows an efficiency very close to the efficiency of a Carnot cycle evolving between the same extreme temperatures. The ratio between the two efficiencies can approach 90%.
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A thermodynamic cycle with a quasi-Isothermal Expansion
International Journal of Hydrogen Energy, 1998Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Giuseppe SpazzafumoAbstract:Abstract The combustion of hydrogen and oxygen makes feasible a steam re-heating by mixing rather than by surface exchange. In such a way the use of several re-heaters is possible as well as the increase of re-heating temperature. The performances of steam power-plants with a large number of super-heaters (5–15) have been analyzed. Some theoretical considerations are also given in order to explain expectations, results and perspectives. Using so many super-heaters makes the Expansion gradually approach Isothermal conditions. A significant reduction of the efficiency gap with respect to the Carnot cycle was therefore expected. A thermal efficiency of 49.2% is achievable. Although this is far from the 61.6% of the Carnot cycle, the study points out some interesting aspects and suggests the basis for further development.
Salvatore Pietro Cicconardi - One of the best experts on this subject based on the ideXlab platform.
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Parametric analysis of a steam cycle with a quasi-Isothermal Expansion
International Journal of Hydrogen Energy, 2001Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Alessandra Perna, Giuseppe SpazzafumoAbstract:Using a hydrogen/oxygen steam generator it is possible to carry out many steam mixing re-heatings without increasing the complexity of a traditional steam power-plant: steam is not required to re-enter the boiler for each re-heating. An Isothermal Expansion could thus be approached by means of several adiabatic Expansions and several steam mixing re-heatings. A theoretical investigation showed that an Isothermal Expansion could achieve high efficiency (up to 70% of HHV) when the waste heat at the turbine outlet is recovered for pre-heating water, hydrogen and oxygen. In a real plant the number of re-heatings that can be carried out, although high, is limited and we can therefore expect an efficiency drop which varies as a function of the number of re-heatings, the re-heating temperature and the maximum pressure. In order to evaluate real cycle performance, a numerical code, specifically created, was implemented.
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A steam cycle with an Isothermal Expansion: the effect of flowvariation
International Journal of Hydrogen Energy, 1999Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Alessandra Perna, Giuseppe SpazzafumoAbstract:Abstract In the present paper the steam cycle proposed by Spazzafumo has been again taken into consideration and the effectof the flow variation on the cycle performances has been investigated. The Isothermal Expansion with increasingflow causes a decrease in cycle efficiency due to the greater condenser losses and, at high superheated temperatures,to the impossibility of full recovering of the available heat at the end of the Expansion. However, using part of thisheat for preheating the required hydrogen and oxygen, yields a significant increase in efficiency. © 1999International Association for Hydrogen Energy. Published by Elsevier Science Ltd. All rights reserved.
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A STEAM CYCLE WITH DIRECT COMBUSTION OF HYDROGEN AND OXYGEN AND AN Isothermal Expansion
Hydrogen Power: Theoretical and Engineering Solutions, 1998Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Alessandra Perna, Giuseppe SpazzafumoAbstract:A new thermodynamical cycle characterised from an Isothermal Expansion has been examined from a theoretical point of view. In the real cycle the Isothermal Expansion could be approached by means of mixing re-heatings. The high temperature steam for mixing is produced in a direct steam generator burning a stoichiometric mixture of hydrogen and oxygen. The theoretical analysis has shown that the reference cycle allows an efficiency very close to the efficiency of a Carnot cycle evolving between the same extreme temperatures. The ratio between the two efficiencies can approach 90%.
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A thermodynamic cycle with a quasi-Isothermal Expansion
International Journal of Hydrogen Energy, 1998Co-Authors: Salvatore Pietro Cicconardi, Elio Jannelli, Giuseppe SpazzafumoAbstract:Abstract The combustion of hydrogen and oxygen makes feasible a steam re-heating by mixing rather than by surface exchange. In such a way the use of several re-heaters is possible as well as the increase of re-heating temperature. The performances of steam power-plants with a large number of super-heaters (5–15) have been analyzed. Some theoretical considerations are also given in order to explain expectations, results and perspectives. Using so many super-heaters makes the Expansion gradually approach Isothermal conditions. A significant reduction of the efficiency gap with respect to the Carnot cycle was therefore expected. A thermal efficiency of 49.2% is achievable. Although this is far from the 61.6% of the Carnot cycle, the study points out some interesting aspects and suggests the basis for further development.
Katsunobu Nishihara - One of the best experts on this subject based on the ideXlab platform.
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theoretical investigation of the spectrum and conversion efficiency of short wavelength extreme ultraviolet light sources based on terbium plasmas
Applied Physics Letters, 2010Co-Authors: Akira Sasaki, Katsunobu Nishihara, Atsushi Sunahara, Hiroyuki Furukawa, Takeshi Nishikawa, F KoikeAbstract:The emission spectrum and conversion efficiency of laser-produced terbium plasmas are theoretically investigated on the basis of computational atomic data. The theoretically calculated spectrum reproduces the main peak of observed spectrum at λ=6.5 nm, which originates from 4d−4f transitions of near palladiumlike ions (Tb19+). A simple model of the Isothermal Expansion of terbium plasma suggests that efficient emission can be achieved by pumping the plasma with a laser pulse at an intensity of approximately one order of magnitude greater than that used with tin sources at λ=13.5 nm.
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Numerical analysis of energy transport by intense resonance line in Lithium plasmas
Journal de Physique IV (Proceedings), 2006Co-Authors: Takeshi Nishikawa, Atsushi Sunahara, K. Gamada, Katsunobu NishiharaAbstract:Energy transport by a strong resonance line like Lyman α has been studied numerically. The corona region of laser-produced Li plasmas is assumed to be the Isothermal Expansion model. As a result, though the peak intensity of Lyman α keeps Planckian value, width of the line becomes broader during the transmission in the corona region. If the optical depth could be controlled thicker much more than unity, available power exceeds the value of surface area x intensity of Planckian x line width of emissivity, and the EUV light source for the semiconductor lithography can be designed by Li target.
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properties of ion debris emitted from laser produced mass limited tin plasmas for extreme ultraviolet light source applications
Applied Physics Letters, 2005Co-Authors: S Fujioka, Katsunobu Nishihara, Hiroaki Nishimura, M Murakami, Youngcesg Kang, Keiji Nagai, T Norimatsu, Noriaki Miyanaga, Yasukazu Izawa, Kunioki MimaAbstract:Properties of ion debris emitted from laser-produced mass-limited tin plasmas have been experimentally investigated for an application to extreme ultraviolet (EUV) lithography. Simple scaling laws to design the mass-limited target, which is a key technique to minimize contamination of the first EUV collection mirror, is discussed. The measured energy spectrum of the tin ions is consistent with a prediction by the Isothermal Expansion model. The average charge state of the tin ions is evaluated to be +5 at 180mm away from the plasma, and higher-energy ions have higher charge state. It was found that not only EUV emission but also ion energy spectra are sensitively affected by the target mass limitation.
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Ion energy spectrum of expanding laser-plasma with limited mass
Physics of Plasmas, 2005Co-Authors: Masakatsu Murakami, Yg Kang, Katsunobu Nishihara, Shinsuke Fujioka, Hiroaki NishimuraAbstract:A simple analytical model is presented for hydrodynamic Expansion of laser-produced plasma with a limited mass, which expands quasi-Isothermally during laser irradiation and quasiadiabatically after turning off the laser. During the Isothermal Expansion, the masses undergo entire disintegration under a relatively long laser pulse, while the ions are being kept accelerated. This physical picture significantly contrasts with that described by the orthodox self-similar solution for a semi-infinite planar rarefaction wave. The two successive Expansions, i.e., Isothermal Expansion followed by adiabatic Expansion, are described, respectively, by different self-similar solutions, which are found to be connected smoothly with each other in time and space. The ion energy spectrum obtained by the model reproduces well experimental results obtained under different geometrical conditions. The maximum ion kinetic energy is also estimated in terms of the laser and target parameters.