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  • Chemistry  (4)
  • Hemodynamics  (2)
  • 5-Oxo-l-pipecolic acid  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Synthesis of 5-oxo-l-pipecolic acid derivatives by rhodium(II) acetate catalyzed cyclization of diazoketones
    Amsterdam : Elsevier
    Tetrahedron Letters 33 (1992), S. 6651-6652 
    Details
    ISSN: 0040-4039
    Keywords: 5-Oxo-l-pipecolic acid ; Diazoketone ; N-H insertion ; Rhodium(II) acetate ; l-Glutamic acid
    Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://linkinghub.elsevier.com/retrieve/pii/S0040-4039(00)61009-2
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  • 2
    Electronic Resource
    Electronic Resource
    Axial development of velocity fields in the porcine main pulmonary artery system (1994)
    Springer
    Heart and vessels 9 (1994), S. 67-78 
    Details
    ISSN: 1615-2573
    Keywords: Pulmonary artery ; Hemodynamics ; Blood velocity ; Pulsed Doppler ultrasound ; Pigs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The aim of this study was to provide detailed data on velocity profile development in the normal porcine main pulmonary artery and its main branches. Under spontaneous hemodynamic conditions in twelve open-chest 90kg pigs, perivascular pulsed Doppler ultrasound was used for blood velocity measurements in the entire cross-sectional area in three axial locations in the main pulmonary artery and along one diameter in the main branches. Computerized threedimensional visualizations of the spatial and temporal development of velocity profiles were made throughout the heart cycle. The results were similar one and two diameters downstream of the pulmonary valve. In the early systolic acceleration phase, the velocity profile became skewed, with the highest velocities (132.7 ± 19.4cm · sec−1) towards the inferior to right superior vessel wall, and rotated counterclockwise 45°–90° during the late acceleration to early deceleration phase in 9 out of 11 pigs. Maximum retrograde velocities (31.4 ± 14.9cm · sec−1) were observed at the inferior to the right superior vessel wall in the late systolic deceleration phase and in early diastole. During diastole, low retrograde to insignificant antegrade velocities were observed. Immediately upstream of the pulmonary bifurcation, the velocity profile disclosed two peaks at locations corresponding to the two main branches. A confined area with retrograde velocities was seen at the right vessel wall in late systole. Low-scale antegrade velocities were observed throughout diastole in the entire cross-sectional area. In the left main branch, the velocity profiles were found to be somewhat skewed towards the left vessel wall, corresponding to the smaller curvature of the left main branch, while the velocity profile in the right main branch was skewed against the superior vessel wall throughout systole. This study thus disclosed that the blood velocity profiles in the main pulmonary artery system were skewed and that mean velocity varied 26%–50% between measuring points, exhibiting an as yet unexplained rotational phenomenon. The skewed velocity profile in the porcine pulmonary trunk indicates that single-point blood velocity measurements can only serve as a basis for cardiac output estimations when used with considerable caution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01751940
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  • 3
    Electronic Resource
    Electronic Resource
    The hemodynamic impact of diffuse myocardial ischemic lesions: An animal experimental model based on intracoronary microembolization (1998)
    Springer
    Heart and vessels 13 (1998), S. 132-141 
    Details
    ISSN: 1615-2573
    Keywords: Disease models, animal ; Coronary disease pathology ; Ventricular function, left physiology ; Swine ; Echocardiography methods ; Radionuclide ventriculography ; Hemodynamics
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary In ischemic heart disease, left ventricular function is affected by a diffuse and segmental loss of myocardium. The decline in the incidence of myocardial infarction and improved early revascularization in acute transmural ischemia predict a change in the natural history of ischemic heart disease. It is now believed that, minor ischemic episodes, which are known to induce multifocal myocardial degeneration, will predominate in the near future. The objective of the present study was to develop a clinically relevant experimental model for investigation of the pathophysiological significance of diffuse ischemic myocardial lesions. Cardiac performance was gradually depressed by selective intracoronary microembolization in 13 pigs. Left ventricular function was quantitated by ejection fraction (EF), pulmonary pressure, cardiac output, and derivatives of left ventricular pressure. Left ventricular volume was estimated by epicardial echocardiography, using a new, unbiased stereological volume estimator. A chronic substudy was performed in order to characterize the histological changes and to evaluate the feasibility of establishing a chronic preparation of the model. Embolization induced acute left ventricular dysfunction; left ventricular pressure change decreased from 966 ± 274 to 637 ± 146mmHg/s, and early diastolic relaxation from 1403 ± 515 to 824 ± 344mmHg/s, respectively. Ejection fraction decreased by 45% ± 5% and cardiac output by 29% ± 11%. End-diastolic volume increased significantly, from 66.1 ± 13.2 to 77.0 ± 19.4 cm3, and end-systolic volume increased from 35.9 ± 13.9 to 52.3 ± 7.6 cm3. No change in heart rate or left ventricular filling pressure was observed. Diffuse ischemic myocardial injury was identified after a mean follow-up of 40 days. Intracoronary microembolization induces acute left ventricular dysfunction due to microinfarcts. Increased left ventricular end-diastolic volume is the initial compensatory response to the acute impairment of cardiac performance in nontransmural myocardial ischemia. This model is suitable for the evaluation of the hemodynamic changes secondary to acute and chronic diffuse loss of functional myocardium.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01747830
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  • 4
    Electronic Resource
    Electronic Resource
    Collection efficiency model based on boundary-layer characteristics for cyclones (1997)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 43 (1997), S. 2446-2455 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In cyclones, the boundary layer formed on the collecting-wall surface acts as a barrier for particle migration toward the wall due to a decreased centrifugal force on particles inside the boundary layer. A new theory for high-efficiency cyclones based on the boundary-layer characteristics is presented. The cyclone was divided into two regions: the turbulent-core region where the centrifugal force is large, and the near-wall region where the centrifugal force is small. Particle trajectories in the turbulent-core region are calculated from the mean fluid motion based on the quasi-steady drag assumption, and the collection probability of particles in the near-wall region is calculated by the deposition velocity that results from both turbulent diffusion and centrifugal force. The deposition velocity by centrifugal force was assumed equal to the equilibrium migration velocity at a certain point inside the boundary layer, and the distance to that point from the wall is assumed to be linearly proportional to the dimensionless-particle relaxation time. When the proportional constant was determined by fitting the theoretical results to experimental data, the theory showed an excellent enhancement in predicting the variation of collection efficiency with the inlet flow velocity and particle size.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690431008
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  • 5
    Electronic Resource
    Electronic Resource
    Turbulence energy and intensity spectra in a baffled, stirred vessel (1964)
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 10 (1964), S. 747-752 
    Details
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The radial components of the turbulence energy and intensity spectra within a stirred, baffled tank are measured with a transducer probe of the type developed by Eagleson et al. (9). The spectra are normalized because absolute levels of the intensity in these high intensity velocity fields cannot be measured with the present technique. Average velocities are also measured with Pitot and Prandtl tubes.Range of measured energy and intensity spectra was 19 to 1,100 cycles/sec. The measured energy spectra show a k-5/3-relation in the low wave number range where the wave number k is less than 100 ft.-1 and a k-10/3-relation in the wave number range of 100 to 1,000 ft.-1. This behavior is found regardless of impeller size, motor speed, and position in tank, in particular radial distance, indicating that the decay of energy spectra is self-preserving. Increasing the viscosity from 0.80 to 103 centipoises results in a progressively steeper slope in the high wave number range. The shape of the intensity spectra is the same as that of the concentration spectra measured by Manning (26, 27).
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aic.690100532
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  • 6
    Electronic Resource
    Electronic Resource
    Thermal behavior, morphology, and some melt properties of blends of polycarbonate with poly(styrene-co-acrylonitrile) and poly(acrylonitrile-butadiene-styrene) (1988)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 28 (1988), S. 1115-1125 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Blends of bisphenol-A polycarbonate (PC) with poly- (styrene-co-acrylonitrile) (SAN) and poly (acrylonitrile-butadiene-styrene) (ABS) prepared by screw extrusion and solution-casting were investigated by differential scanning calorimetry and scanning electron microscopy. From the measured glass-transition temperatures (Tg) and specific heat increments (ΔCp) at the Tg, SAN appears to dissolve more in the PC-rich phase than does PC in the SAN-rich phase. Also, the decrease of Tg (PC) in PC/ABS blends is larger than in the PC/SAN blends. From the Tg behavior and the electron microscopy study, it is suggested that the compatibility increases more in the SAN-rich compositions than in the PC-rich compositions of the blends. In the study of extrudate swell of the PC/SAN blends and the PC/ABS blends, the maximum level of extrudate swell is reached at 0.5 weight fraction of PC for both blend systems. The Flory-Huggins polymer-polymer interaction parameter (χ12) between PC and SAN was calculated and found to be 0.034 ± 0.004. A similar value of χ for PC and SAN was found with the PC/ABS blends.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760281706
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  • 7
    Electronic Resource
    Electronic Resource
    32. Wärmeübergang und Druckverlust im Mantelraum von Rohrbündelwärmeübertragern ohne Umlenkeinrichtungen bei turbulenter Strömung (1994)
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 66 (1994), S. 1180-1181 
    Details
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cite.330660933
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