To examine whether hypoxia exerts effect on the expression of basic fibroblast growth factor (bFGF) in pulmonary vascular pericytes (PC), cell culture, in situ hybridization with probe of digoxigenin-11-dUTP-labled cDNA, immunocytochemistry and image analysis were employed in this study. The results showed that the expression amount of bFGF mRNA and protein in PC of hypoxia (H) group was 1.31 times (P < 0.01) and 1.17 times (P < 0.01) that of normoxia (N) group respectively. It suggests that hypoxia can directly enhance the expression of bFGF mRNA and protein in PC. Increased expression of bFGF may play an important role in the process of PC proliferation and differentiation of PC into smooth muscle-like cells.

This paper investigates the nonlinear dynamics of a fluid-conveying curved pipe subjected to motion constraints and harmonic excitation. At first, the background theory for curved pipes conveying fluid with motion constraints is presented. Then, emphasis is placed on the possible nonlinear dynamic behaviors of a constrained curved pipe subject to a harmonic excitation. For such a forced dynamical system, calculations of bifurcation diagrams, phase-plane portraits, time responses, power spectrum diagrams and Poincare maps of the oscillations clearly establish the existence of the chaotic motions and quasi-periodic motions. Moreover, it is found that the route to chaos is through a sequence of period-doubling bifurcations. Finally, the difference in the nonlinear dynamics between the self-vibration system and forced system is further discussed.

This paper investigates the nonlinear dynamics of a fluid-conveying curved pipe subjected to motion constraints and harmonic excitation. At first, the background theory for curved pipes conveying fluid with motion constraints is presented. Then, emphasis is placed on the possible nonlinear dynamic behaviors of a constrained curved pipe subject to a harmonic excitation. For such a forced dynamical system, calculations of bifurcation diagrams, phase-plane portraits, time responses, power spectrum diagrams and Poincare maps of the oscillations clearly establish the existence of the chaotic motions and quasi-periodic motions. Moreover, it is found that the route to chaos is through a sequence of period-doubling bifurcations. Finally, the difference in the nonlinear dynamics between the self-vibration system and forced system is further discussed.

In-plane vibrations of curved pipes conveying fluid are investigated by using the generalized differential quadrature rule (GDQR) proposed. The "modified inextensible" theory for the curved pipes is considered, and the steady-state combined force is taken into account. Several examples of curved pipes conveying fluid with different boundaries are presented to illustrate the validity of the GDQR. The obtained natural frequencies compare quite well with those predicted by the finite element method. Based on the GDQR, the effect of some key parameters on the natural frequencies of the pipe system is further discussed. Compared with other methods, GDQR is more convenient to deal with the boundary conditions of the pipe and gives acceptable precision in the numerical results. This method can be useful for further study of the nonlinear dynamics of pipes conveying fluid. (C) 2007 Elsevier Ltd. All rights reserved.

We present a symbolic-numeric hybrid method, based on sum-of-squares (SOS) relaxation and rational vector recovery, to compute inequality invariants and ranking functions for proving total correctness and generating preconditions for programs. The SOS relaxation method is used to compute approximate invariants and approximate ranking functions with floating point coefficients. Then Gauss-Newton refinement and rational vector recovery are applied to approximate polynomials to obtain candidate polynomials with rational coefficients, which exactly satisfy the conditions of invariants and ranking functions. In the end, several examples are given to show the effectiveness of our method.

A new polarization-independent dual-wavelength fibre laser by fabricating a uniform FBG and a chirped FBG in a polarization-maintaining erbium-doped fibre (PM-EDF) is proposed and demonstrated. The wavelength spacing is 0.18nm and the optical signal-to-noise ratio is greater than 50dB with pump power of 246mW. Chirped FBG is used to make the reflectivity wavelengths of two PM-FBGs match easier. Since both EDF and FBGs are polarization-maintaining without splices and the two wavelengths are polarization-independent, the maximum amplitude variation and wavelength shifts for both lasing wavelength with 3-min intervals over a period of six hours are less than 0.2 dB and 0.005 nm, respectively, which shows stable dual-wavelength output.

Zusammenfassung  In unserer Studie wurden 798 F?lle mit Mitralklappenfehlern analysiert. Die Beziehungen zwischen verschiedenen Parametern und den NYHA-Klassen, der Erfolg der Operation, die Operationsletalit?t, die Lebensqualit?t und die 10-Jahres-überlebenswahrscheinlichkeit wurden diskutiert. Es wird empfohlen, bei Patienten mit Indikation zur Mitralkommissurotomie (bei reiner Mitralstenose ohne Verkalkung an der Klappe, und bei kombinierten Mitralvitien mit überwiegender Stenose, aber ohne erhebliche Vergr??erung des linken Ventrikels) die Operation frühzeitig anzustreben. Bei Patienten, bei denen Kommissurotomie nicht mehr indiziert ist, ist der Mitralklappenersatz baldigst durchzuführen. Influence of surgical intervention on the course of patients with rheumatic mitral valvular defects Abstract  A retrospective study of 798 patients from Essen University Medical Hospital during the period 1960–1987 with operation performed due to valvular heart disease was undertaken. Among them were 324 suffering from mitral stenosis, 12 from mitral regurgitation, 462 from mixed mitral valvular diseases. The surgical treatment consisted of commissurotomy in 611 patients, and prosthetic valve replacement in 187 patients. Follow-up studies showed: Before and after operation, occurrence of embolism was 16.5 vs 8.7 %; status of class of cardiac function (NYHA) from group with commissurotomy was 3.1 vs 2.0; NYHA classification in group of prosthetic replacement was 3.1 vs 1.9; 10 years survival rate after commissurotomy was 95.2 %; after valve replacement it was 80.2 %; early letality rate after operation (at or within 2 months after operation) depended on 1) the type of operations commissurotomy 2.8 %, valve replacement 10.2 %; 2) the state of cardiac function: in class IV it was 12.9 %, in class III 4.6 %; 3) the number of operations: in only operation it was 4.8 %, in reoperations 19.5 %. Schlüsselw?rter  Mitralvitien - Mitralkommissurotomie - Mitralklappenersatz - Prognose

A driving mechanism for a pneumatic tool includes a motor and an elongated connector. The motor has a body portion and a rotor shaft mounted rotatably to the body portion. The rotor shaft has an engaging section which extends beyond the body portion. The engaging section of the rotor shaft has an externally threaded portion adjacent to the body portion and a non-threaded portion which is connected to and which extends away from the externally threaded portion. The connector has first and second ends and an axial hole extending from the first end of the connector. The axial hole has an internally threaded section formed adjacent to the first end of the connector and a non-threaded section which is connected to the internally threaded section and which extends away from the first end toward the second end of the connector. The externally threaded portion of the rotor shaft engages threadedly the internally threaded section of the connector. The non-threaded portion of the rotor shaft engages fittingly the non-threaded section of the connector.

Factors affecting the largest range of a CO 2 lidar system are discussed. According to the basic form of the lidar equation, influences of parameters related to optical properties of the laser itself, object characteristics and atmospheric transmission are pointed out. Influences of the lidar system itself on the range are discussed. Using a personal computer, qualitative and quantitative analysis of range is performed