CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018

While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI

CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018

While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI

Experimental Study of Turbulent Diffusion Flames Stabilized on a Bluff Body : Flame Structure

An experimental investigation was conducted on the structure of turbulent diffusion flames of hydrogen stabilized on a bluff body. A coaxial jet diffusion flame was formed using a cylindrical nozzle with an extremely thick rim, which works as a bluff body. In the present study, special attention was paid to the effect of combustion on the aerodynamic processes. The following results were obtained. (1) The combustion markedly enhances the penetration of the central fuel jet. (2) The laminarization phenomenon, reported in simple jet diffusion flames, was observed more conspicuously in this combustion field as well, and it was assumed to exert an important influence on the flame structure. (3) An accelerating flow field often exists in complicated flow fields with a reverse flow, where turbulence generation terms containing Reynolds normal stress become negative. This phenomenon sometimes exerts considerable effects on the turbulence behavior.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002976848

Persistence of Laminar Flamelet Structure Under Highly Turbulent Combustion

We have investigated the premixed flame structure in highly turbulent flow with a cyclone-jet combustor. Based on the turbulent properties determined by Slot-Correlation method, the condition of U_m20 m/s belongs to the distributed reaction zone regime on the combustion diagram. Also, we have quantitatively estimated the reaction zone thickness, using the probability of reaction zone existing. Results show that the dependence of reaction zone thickness on equivalence ratio is very similar to those of the experimental values by Yamaoka and Tsuji or the Zeldovich thickness. When the exit velocity is increased, the reaction zone thickness is almost constant for Ka>1. Hence, the persistence of laminar flamelet structure is observed, even when the Kolmogorov scale is smaller than reaction zone thickness. It could be concluded that the reaction region remains undisturbed with thin reaction zone under highly turbulent conditions. These results are useful for modeling turbulent combustion.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110003479169

Mechanism of Flame Stability in a Rotating Flow : Combustion Characteristics of Tubular Flames in a Hydrogen/Air Mixture

The effects of rotation on the stability and structure of tubular flames have been investigated for a lean hydrogen/air mixture, and mechanism of flame stability in a rotating flow has been discussed. Results show that with increasing intensity of rotation, (1) the flame diameter increases, while thickness of the luminous zone decreases, (2) the fuel concentration at the extinction decreanes, i. e., the stable region expands, (3) the radial temperature distribution becomes an M-shaped profiles, and (4) flame temperature T_f increases near extinction. These results are almost the same as those obtained for a methane/air mixture. The mechanism for these phenomena is supposed to be explained with the coupled effects of pressure diffusion and stretch effect. The present experimental results provide very useful information for discussing the flame stability and the transport phenomena in a vortex flow

Modeling of Hydrogen Jet Diffusion Flames (On the Direct Influence of Molecular Viscoty

It was believed that the increase of molecular viscosity due to high temperature raises the dissipation rate of turbulence in low-turbulent regions in a combustion field. Hence, the objective of the present study was to verify this both experimentally and theoretically. Experiments were carried out on jet diffusion flames of hydrogen, and then, a numerical simulation was conducted for the experimental results. In the simulation, the κ-ε two-equation model was used as a turbulence model and a new source term was added to the κ-equation to represent the dissipation rate of turbulence kinetic energy due to molecular viscosity. The calculated results agree well with the experimental ones. It was found that the new source term suppresses turbulence in low turbulent regions situated around the nozzle exit and the periphery of jets, and changes the condition in the whole combustion field greatly. The present work suggested that consideration of the viscous effect is important in the modeling of turbulent combustion fields.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002494156

The Local Reaction Rate in Round-Jet Diffusion Flames

A combustion model for turbulent diffusion flames is estimated frequently through the comparison of the simulated result with the experimental one. Usually, profiles of time-averaged concentration and temperature are used in that comparison, because the local reaction rate cannot be directly measured. However, since their profiles are also influenced largely by transport phenomena, it is difficult to estimate the combustion model properly with this method. Therefore, it is desirable to calculate the local reaction rate from experimental results and compare it with the simulated one. In the present study, from this point of view, the local reaction rate was tried to obtain by numerical calculation using measured values for a hydrogen jet diffusion flame. Then, it was suggested through the comparison of the obtained result with the simulated one that the method proposed here can provide reliable values for the local reaction rate.・rights：日本機械学会・rights：本文データは学協会の許諾に基づきCiNiiから複製したものである・relation：isVersionOf：http://ci.nii.ac.jp/naid/110002981414