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91.
In addition to left ventricular pump failure and low cardiac output, structural and metabolic alterations of skeletal muscle are thought to contribute to exercise intolerance seen in patients with CHF. Studies using cardiac myocytes have implicated nitric oxide elaborated by inducible nitric oxide synthase (iNOS) as a potential agent associated with the genesis of dilated cardiomyopathy. The present study was designed to locate iNOS in the working skeletal muscle of patients with congestive heart failure. Specific antibodies were used to detect iNOS by immunohistochemistry in skeletal muscle biopsies (m. vastus lateralis) of 37 patients with left ventricular pump failure and 8 normal controls. The expression was restricted to skeletal muscle myocytes and was increased five- to ninefold in patients with chronic heart failure. There was no statistically significant difference in iNOS expression between patients with dilated cardiomyopathy and those with ischemic cardiomyopathy. The finding of a locally increased expression of iNOS and the experimental evidence that NO attenuates the contractile performance of the skeletal muscle suggest that the expression of iNOS may be responsible for the exercise intolerance seen in patients with chronic heart failure. 相似文献
92.
Uneus L. Artursson T. Mattsson M. Ljung P. Wigren R. Martensson P. Holmberg M. Lundstrom I. Spetz A.L. 《IEEE sensors journal》2005,5(1):75-81
Metal insulator silicon carbide field-effect transistor sensors, metal-oxide sensors, and a linear Lambda sensor in an electronic nose was used to measure on-line in hot flue gases from a boiler. Flue gas from a 100-MW pellets-fuelled boiler has been used to feed the experimental setup. Several reference instruments, which measure the flue gases in parallel to the sensor array, are connected to the electronic nose. Data was collected during six weeks and then evaluated. Using principal component analysis as the data evaluation method, different operating modes for the boiler have been identified in the data set. The different modes could be described in terms of high or low O/sub 2/ and CO concentration. Furthermore, we have shown that it seems possible to use a sensor array to determine the operating mode of the boiler and, by partial least-squares models, measure the CO concentration when the boiler operates in its optimum mode. 相似文献
93.
The purpose of this paper is to improve the tools available for analyzing and evaluating land-use and transport policies in a regional planning context. A normative residential location submodel is combined with a predictive submodel for the location of employment. The demand side of the residential location submodel is formulated as a nested multinomial logit model of the joint choice of residential location and transportation mode. The cost of commuting is assumed to be a major determinant of locational choice. The employment location submodel is based on the assumption that accessibility to the labor force is the strategic location factor. Two versions of the submodels are proposed corresponding to a post- and pre-distribution modal split in the familiar four-step transport model. Policy tests of a newly proposed, large-scale traffic investment program in the Stockholm region are reported.An earlier version of this paper was presented at the 30th European Congress, Istanbul, August 1990. 相似文献
94.
In granulation, coating or drying of slurries on inert particles a liquid phase is added to a gas-spouted bed. The effect of liquid injection on spouting velocity, fountain height, bed pressure drop and stability of the spouting regime is examined in a 0.15 m diameter bed with four types of inert particles 2 to 5 mm in size, 1140 to 2880 kg/m3 in true density, and 1.3 and 1400 mPa·s in liquid viscosity. Key factors are the liquid content and the presence of cohesive forces due to liquid bonds between particles. In a spoutability chart the maximum spoutable liquid content is related to the ratio of inertial force of a particle to the viscous or cohesive force exerted onto the particle by the liquid film. The spoutability chart serves to define regions of stable spouting. 相似文献
95.
96.
Due to the demand of the industry for an increase of the number of I/Os, while decreasing the die size, the bond pads had
to shrink and design restrictions for the active structures underneath had to fall. This leads to new challenges for the electrical
probing and the mechanical robustness of the under-pad structures. This paper presents analytical and numerical simulation
approaches for predicting the force/travel relation of buckling beam-probes that are used for testing the electrical functionality
of back-end-of-line (BEOL) interconnect system underneath a chip pad. For this purpose we investigate, first, in a closed-form
manner, the elastic stability of the probe needle according to the large deflection theory of buckled bars. Second, we determine,
for a specific geometry of the beam, the probe forces as functions of the probe card overdrive by using the closed-form methods
as well as finite-element simulations. The results are finally compared to that obtained in (probe card) experiments. 相似文献
97.
Thermal residual stresses have been measured using X-ray diffraction in an Al-2% Mg matrix with 10, 20 or 26 vol % Al2O3 short fibres. Stress measurements were made at room temperature as well asin situ at elevated temperatures up to 250?C. The thermal stresses arise due to the difference in coefficient of thermal expansion (CTE) between the matrix and the reinforcement. The largest CTE is found in the matrix, resulting in tensile residual stresses after a temperature drop, e.g. after processing or annealing. A high fraction of reinforcement implies higher matrix stresses than a low fibre content. The stresses decrease with increasing temperature for all fibre volume fractions. Measurements are compared with calculations using a modified Eshelby model for equivalent inclusions. Parameters taken into account in the model are coefficient of thermal expansion, Young's modulus, and volume fraction and geometric shape of the reinforcing phase. A good correlation between calculations and experimental results has been found, bearing in mind that no plasticity is taken into account in the Eshelby model. The plastic behaviour of the composites has been described using a model based on a rigid spherical cavity in an elastic-plastic matrix. 相似文献
98.
99.
In the first part of this contribution, a mathematical model was presented for a liquid fluidized bed using immobilized enzymes, with reversible Michaelis-Menten kinetics. This part is focused on the experimental results. The reaction kinetics of native and immobilized enzymes was determined in continuous stirred tank reactors under comparable conditions. The influence of external mass transfer was investigated in a fixed bed reactor column. The extend of pore diffusional resistance was examined in a continuous stirred tank reactor and with a numerical simulation. Hydrodynamics was measured in different reactor columns (diameter dt = 0.052 ? 0.225 m; length L: 1.0–2.0m) and with a static mixer. Further, the concentration profile was determined in a fluidized bed reactor with side stream analysis for different biocatalyst samples, fluid velocities and bed heights. The simulation of experimental results indicates that they are well described by the developed model. Furthermore, the model is well suited to predicting the influence of specific parameters on the effective kinetics of the biocatalyst and the expansion of the fluidized bed. 相似文献
100.
In the first part of this paper, a mathematical model is presented for a liquid fluidized bed bioreactor using immobilized enzymes with reversible Michaelis-Menten kinetics. The model is based on the axial dispersion model for the bulk liquid phase. Inter- and intraparticle mass transfer as well as enzyme catalyzed reaction inside the porous beads are considered. The overall efficiency of the biocatalysts is calculated by a numerical routine. For the calculation of the concentration profile inside the reactor, a semi-analytical solution is derived which takes into account the height dependence of the effectiveness factor. 相似文献