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The hydrodynamical similarities between the bubbly flow in a bubble column and in a pipe with vertical upward liquid flow are investigated. The system concerns air/water bubbly flow in a vertical cylinder of 14.9 cm inner diameter. Measurements of the radial distribution of the liquid velocity, gas fraction and the bubble velocity and size are performed using laser Doppler anemometry for the liquid velocity and a four-point optical fibre probe for the gas fraction, bubble velocity and size. The averaged gas fraction was 5.2% for the bubble column (with a superficial liquid velocity of zero) and 5.5% for the bubbly pipe flow at a superficial liquid velocity of 0.175 m s−1. From a hydrodynamical point of view, the two modes of operation are very similar. It is found that in many respects the bubbly pipe flow is the superposition of the flow in the bubble column mode and single-phase flow at the same superficial liquid velocity.The radial gas fraction profiles are the same and the velocity profiles differ only by a constant offset: the superficial liquid velocity. This means that the well-known large-scale liquid circulation (in a time-averaged sense) of the bubble column is also present in the bubbly pipe flow. For the turbulence intensities it is found that the bubbly pipe flow is like the superposition of the bubble column and the single-phase flow at the superficial liquid velocity of the pipe flow, the former being at least an order of magnitude higher than the latter. The large vortical structures that have been found in the bubble columns are also present in the bubbly pipe flow case, partly explaining the much higher ‘turbulence’ levels observed.

Objectives: Bone marrow stromal cells are capable of differentiating into cardiomyogenic cells. We tested the hypothesis that transcoronary implantation of bone marrow stromal cells may regenerate infarcted myocardium and reduce cardiac dysfunction.Methods: Isolated bone marrow stromal cells from the isogenic donor rats were transfected with LacZ reporter gene for cell labeling. To induce cardiomyogenic differentiation, the bone marrow stromal cells were treated with 5-azacytidine before implantation. Two weeks after left coronary ligation, these cells (1 ϫ 10 6 in 150 L) were infused into the briefly distally occluded ascending aorta of the recipient rats (n ϭ 15) to simulate direct coronary infusion clinically. Control animals were infused with cell-free medium (n ϭ 14). Cardiac function was evaluated by echocardiography at preimplantation and 4 and 8 weeks postimplantation. The hearts were then immunohistochemically studied to identify phenotypic changes of implanted bone marrow stromal cells.Results: Immediately after cell infusion, the bone marrow stromal cells were trapped within coronary vessels in both infarcted and noninfarcted areas. However, after 8 weeks, most of the cells were identified in the scar and periscar tissue, expressing sarcomeric myosin heavy chain and cardiomyocyte-specific protein troponin I-C. Some bone marrow stromal cells were found to be connected to the adjacent host cardiomyocytes with gap junction. Two-way repeated-measures analysis of variance revealed significant improvement in fractional shortening and end-diastolic and end-systolic diameter of the left ventricle (P ϭ .0465, .002, .0004, respectively) in the bone marrow stromal cell group. Conclusions:Although bone marrow stromal cells had been reported to improve cardiac function when injected directly into the myocardial scar, this study demonstrated for the first time that bone marrow stromal cells can be delivered via the coronary artery, as they are capable of targeted migration and differentiation into cardiomyocytes in the scar tissue to improve cardiac function. With the recent advent in stem cell biology, it has been shown that an adherent population of bone marrow cells in culture that can be expanded in vitro, known as "marrow stromal cells" (MSCs), contain adult stem cells that can give rise to various mesenchymal and nonmesenchymal cell types. [1][2][3][4] Since Makino and colleague 5 demonstrated that cardiomyogenic differentiation of MSCs in vitro in 1999, several in vivo studies including From the

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To mitigate global warming, a system dissolving huge amounts of CO2 gas captured from fossil fuel fired power plants into the ocean with high acceptance by the ocean environment is indispensable. To this aim, we propose a sequestration system of CO2 in the deep ocean. The system is an inverse-J pipeline set in the ocean at a depth of 200−3000 m. In the system, a pumping effect by buoyancy of the dissolving CO2 bubbles is used to transport CO2-rich seawater to great depths. In the present paper, we discuss characteristics and performance of our proposal on the basis of experimental and numerical investigation. In a laboratory-scale experiment (pipe diameter of 25 mm and pipe height of 7.69 m), we observed over 98% dissolution of injected CO2 gas into tap water. The liquid-phase flow caused by gas-lift effect was strong enough to transport the CO2-rich water including nondissolved tiny bubbles into the deep ocean. Then a numerical simulation based on the experimentally derived models was applied to a system considering 10 MW class power plants. The results showed that our proposal is hopeful for an efficient method of CO2 disposal into the deep ocean.

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Strong expression of the inducible form of nitric oxide synthase (NOS II) has been shown in the myocardium of patients with myocardial infarction (MI). We hypothesized that NOS II plays an important role in the development of MI and subsequent heart failure and that inhibition of NOS II may beneficially alter the course of the disease. Long-term administration (2 mo) of the selective NOS II inhibitor S-methylisothiourea (SMT) to rats with MI significantly improved cardiac function. A significant drop in mortality, lung water content, infarct size, and cardiomyocyte hypertrophy was also associated with the use of SMT. Plasma concentration of nitrite and nitrate was also reduced by SMT. Short-term administration of SMT (first 2 wk only) significantly reduced infarct size; however, it did not improve cardiac dysfunction measured 2 mo after MI. These findings demonstrate that induction of NOS II during MI exerts negative effects on cardiac function and structure. Long-term administration of a selective NOS II inhibitor may prove to be beneficial in the treatment of MI and congestive heart failure.

Xenogeneic bone marrow stromal cells implanted into acutely ischemic myocardium induced by coronary artery ligation were immunologically tolerated, survived and differentiated, resulting in a cardiac chimera which improved left ventricular function. This unique immunologic tolerance may suggest the feasibility of using bone marrow stromal cells as universal donor cells.