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排序方式: 共有622条查询结果,搜索用时 15 毫秒
131.
Yoghurts are mostly produced from cow milk and to a very limited extent from ewe milk. The evolution of caseins and whey proteins in ovine milk submitted to different thermal treatments (63 degrees C/30 min; 73 degrees C/15 min; 85 degrees C/10 min or 96 degrees C/5 min) was followed during fermentation of yoghurts and during their storage up to 14 days, using two different sets of starters. One set of starter LAB was a "ropy" culture (YC-191), which is a well-defined mixed strain culture containing Streptococcus thermophilus ST-143 and Lactobacillus delbrueckii subsp. bulgaricus (LB-18 and LB-CH2). The other set of starter bacteria (YC-460) was a standard yoghurt culture("non-ropy") containing mixed strain culture of Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus. Contents of free amino groups in produced yoghurts increased gradually during the fermentation, up to a maximal value obtained after 4 h fermentation, then they did not change significantly during storage of yoghurt produced with YC-191 starter. In contrary, a large drop in the amount of free amino groups was observed in the first 24 h of storage in the case of yoghurt made with YC-460 indicating that microorganisms continue still to grow in low temperatures. During fermentation and storage of both yoghurt types, alpha-lactalbumin was hydrolyzed to a slightly bigger extent than beta-lactoglobulin. During fermentation, beta-casein was slightly more degraded than alpha(s)-caseins; however, the opposite was observed during storage up to 14 days. Generally, a more intense heat pretreatment led to a higher degradation of whey proteins and caseins during fermentation and storage. Differences in proteolytic activity between the two starters used (whey proteins more degraded by YC-191; caseins more degraded by YC-460) may lead to improvement in production and formulation of yoghurts differing in their physicochemical and rheological properties. 相似文献
132.
Aprahamian M Bour G Akladios CY Fylaktakidou K Greferath R Soler L Marescaux J Egly JM Lehn JM Nicolau C 《Chembiochem : a European journal of chemical biology》2011,12(5):777-783
Myo-inositol trispyrophosphate (ITPP), a synthetic allosteric effector of hemoglobin, increases the regulated oxygen-releasing capacity of red blood cells (RBCs), leading to suppression of hypoxia-inducible factor 1α (HIF-1α) and to down-regulation of hypoxia-inducible genes such as vascular endothelial growth factor (VEGF). As a consequence, tumor growth is markedly affected. The effect of weekly intravenous injection of ITPP on an orthotopic, syngenic rat hepatocellular carcinoma (HCC) model was compared to that for untreated animals and animals subjected to conventional Doxorubicin chemotherapy. The longitudinal examination of HCC was performed by microCT imaging, and the cellular and molecular changes were evaluated by histology and Western blotting analysis of HIF-1α, VEGF, and caspase-3 gene expression in the tumor and in the surrounding liver. Hematologic impact was evaluated by blood cell-count measurement and determination of P50 (oxygen partial pressure for a 50 % oxygen saturation of hemoglobin). The HCC evaluation by microCT revealed a high potency of ITPP for tumor growth inhibition, thus allowing long-term survival and even cure of almost all the treated animals. The P50 value of hemoglobin in RBCs underwent a shift of 30 % following ITPP injection. Under these conditions, HIF-1α activity was strongly decreased, VEGF expression was down-regulated, and apoptosis was induced in HCC and surrounding liver cells, as indicated by Caspase-3 expression. ITPP did not affect hematologic parameters during treatment. The observations of in vivo tumor eradication suggest a significant clinical potential for ITPP in cancer therapy. 相似文献
133.
In this paper, an efficient method for directly computing a reliable estimate of the maximal structured singular value μ is proposed. A method, which directly computes a μ upper bound over a frequency interval, is first extracted from Ferreres and Biannic (Proc. ACC 4 (1998) 2294–2298). The problem is then to evaluate the conservatism of this upper bound by computing an accurate μ lower bound which is the central issue of the paper. The proposed algorithm is successfully applied—with a reasonable computational effort—to a challenging aeronautical application, namely the evaluation of the robustness properties of the flight control system of a flexible transport aircraft. 相似文献
134.
Pre-combustion, post-combustion and oxy-combustion in thermal power plant for CO2 capture 总被引:1,自引:0,他引:1
Mohamed Kanniche Ren Gros-Bonnivard Philippe Jaud Jose Valle-Marcos Jean-Marc Amann Chakib Bouallou 《Applied Thermal Engineering》2010,30(1):53-62
This paper presents a summary of technical-economic studies. It allows evaluating, in the French context, the production cost of electricity derived from coal and gas power plants with the capture of CO2, and the cost per tonne of CO2 avoided. Three systems were studied: an Integrated Gasification Combined Cycle (IGCC), a conventional combustion of Pulverized Coal (PC) and a Natural Gas Combined Cycle (NGCC). Three main methods were envisaged for the capture of CO2: pre-combustion, post-combustion and oxy-combustion.For the IGCC, two gasification types have been studied: a current technology based on gasification of dry coal at 27 bars (Shell or GE/Texaco radiant type) integrated into a classical combined cycle providing 320 MWe, and a future technology (planned for about 2015–2020) based on gasification of a coal–water mixture (slurry) that can be compressed to 64 bars (GE/Texaco slurry type) integrated into an advanced combined cycle (type H with steam cooling of the combustion turbine blades) producing a gross power output of 1200 MWe. 相似文献
135.
Ørnulf Nordseth Chang Chuan You Stefano Gariglio Jean-Marc Triscone Charles H. Ahn Jostein K. Grepstad 《Thin solid films》2010,518(19):5471-2980
Ferroelectric Pb0.92La0.08Zr0.4Ti0.6O3 (PLZT) thin films were deposited on SrTiO3-buffered Si(001) substrate by on-axis radio frequency magnetron sputtering. X-ray diffraction analysis revealed epitaxial growth of monocrystalline PLZT films, with an (001) rocking curve full width at half maximum of ∼ 0.3°. φ-scans showed 45° in-plane orientation of the perovskite unit cell relative to that of silicon. The elemental composition of the thin film heterostructure was examined by Auger sputter depth profiling measurements. The recorded profiles suggest that the SrTiO3 buffer layer serves not only as a template for epitaxial growth, but also as a barrier suppressing Pb-Si interdiffusion between the PLZT layer and the Si substrate. The surface roughness of the PLZT layer was measured at ∼ 4 nm for films with ∼ 500 nm thickness. Wavelength dispersions for the refractive index (n) and the extinction coefficient (k) were obtained from spectroscopic ellipsometry measurements, with n ∼ 2.48 at the main communication wavelength λ = 1550 nm and k < 0.001 for λ > 650 nm. Recorded polarization vs. electric field loops for the PLZT epilayer, with a SrRuO3 electrode layer interposed between PLZT and SrTiO3, showed a remnant polarization Pr ≈ 40 µC/cm2 and coercive field Ec ≈ 100 kV/cm. These findings suggest that the sputter-deposited PLZT thin films retain the functional properties critical to ferroelectric and electro-optic device applications, also when integrated on a semiconductor substrate. 相似文献
136.
137.
Application of Reconfigurable CORDIC Architectures 总被引:1,自引:0,他引:1
Oskar Mencer Luc Séméria Martin Morf Jean-Marc Delosme 《The Journal of VLSI Signal Processing》2000,24(2-3):211-221
Reconfiguration enables the adaption of Coordinate Rotation DIgital Computer (CORDIC) units to the specific needs of sets of applications, hence creating application specific CORDIC-style implementations. Reconfiguration can be implemented at a high level, taking the entire CORDIC unit as a basic cell (CORDIC-cells) implemented in VLSI, or at a low level such as Field-Programmable Gate Arrays (FPGAs). We suggest a design methodology and analyze area/time results for coarse (VLSI) and fine-grain (FPGA) reconfigurable CORDIC units. For FPGAs we implement CORDIC units in Verilog HDL and our object-oriented design environment, PAM-Blox. For CORDIC-cells, multiple reconfigurable CORDIC modules are synthesized with state-of-the-art CAD tools. At the algorithm level we present a case study combining multiple CORDICs based on a geometrical interpretation of a normalized ladder algorithm for adaptive filtering to reduce latency and area of a fully pipelined CORDIC implementation. Ultimately, the goal is to create automatic tools to map applications directly to reconfigurable high-level arithmetic units such as CORDICs. 相似文献
138.
Shen-Fu Hsiao Chun-Yi Lau Jean-Marc Delosme 《The Journal of VLSI Signal Processing》2000,25(2):155-166
Redundant Implementations of Multi-dimensional CORDIC algorithms are presented where the carry-ripple additions are replaced by carry-free signed-digit additions. Both folded (iterative) and unfolded (pipelined) architectures are considered in the redundant implementation. Furthermore, the scaling iterations are merged with the unscaled CORDIC iterations in the folded CORDIC architecture in order to reduce the overall computation time of one CORDIC operation. The redundant multidimensional CORDIC is then applied to the singular value decomposition of complex matrices, with either a folded or an on-line architecture. The resulting processing speed is higher than with alternative approaches based on 2-D CORDIC. 相似文献
139.
Jean-Marc Amann Mohamed Kanniche Chakib Bouallou 《Clean Technologies and Environmental Policy》2009,11(1):67-76
The aim of this study is to assess the conversion of a natural gas combined cycle power plant (NGCC) using an advanced gas
turbine (GE9H) for CO2 pre-combustion capture. The natural gas is reformed in an auto-thermal reformer (ATR) either with pure oxygen or with air.
After water-shift conversion of CO into CO2 and physical CO2 recovery, the synthesis gas contains a high fraction of H2. It is diluted with N2 and steam to lower its low heating value (LHV) for NO
X
emission control. Oxygen purity and reforming pressure have little impact on the performances. High-pressure reforming is
preferred to reduce the process size. Air reforming results in a slightly higher efficiency but in a bigger process too. The
CO2 recovery rate has a big impact on the power plant efficiency since a lot of steam is required to lower the heating value
(LHV) of the synthesis gas leaving the recovery process. Two values of LHV have been assessed. Steam consumption for natural
gas reforming and synthesis gas dilution are the main consuming elements.
An erratum to this article can be found at 相似文献
140.
Christian Urzì Damian Hertig Christoph Meyer Sally Maddah Jean-Marc Nuoffer Peter Vermathen 《International journal of molecular sciences》2022,23(12)
NMR flow devices provide longitudinal real-time quantitative metabolome characterisation of living cells. However, discrimination of intra- and extracellular contributions to the spectra represents a major challenge in metabolomic NMR studies. The present NMR study demonstrates the possibility to quantitatively measure both metabolic intracellular fingerprints and extracellular footprints on human control fibroblasts by using a commercially available flow tube system with a standard 5 mm NMR probe. We performed a comprehensive 3D cell culture system characterisation. Diffusion NMR was employed for intra- and extracellular metabolites separation. In addition, complementary extracellular footprints were determined. The implemented perfused NMR bioreactor system allowed the determination of 35 metabolites and intra- and extracellular separation of 19 metabolites based on diffusion rate differences. We show the reliability and sensitivity of NMR diffusion measurements to detect metabolite concentration changes in both intra- and extracellular compartments during perfusion with different selective culture media, and upon complex I inhibition with rotenone. We also demonstrate the sensitivity of extracellular footprints to determine metabolic variations at different flow rates. The current method is of potential use for the metabolomic characterisation of defect fibroblasts and for improving physiological comprehension. 相似文献