• 한국군사과학기술학회지
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• 제4권1호
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• pp.20-29
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• 2001

We recently developed a friability test procedure, which will be used as one of substance tests for Extremely Insensitive Detonating Substances(EIDSs) in Test Series 7 of the United Nations. This test was intended to assess the susceptibility of insensitive explosives to the break-up as high strain rate and subsequent ignition characteristics of the deformed material. We designed an air gun system using the hydro code simulation. The projectile velocities of the gun were in good agreement with those predicted by the hydro code with an inert material. Three different types of explosives, melt castable Comp B, castable plastic bonded explosives(PBXs), and pressable PBXs were tested during the development of the test procedure. Two tastable PBXs, i.e. DXD-09 and DXD-10, which are currently under development as candidate formulations of EIDS were classified as EIDS, since test results with these formulations were far better than the criterion of the UN Test Series 7.

• The Korean Journal of Physiology and Pharmacology
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• 제26권2호
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• pp.87-94
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• 2022

Myocardial infarction promotes cardiac remodeling and myocardial fibrosis, thus leading to cardiac dysfunction or heart failure. Peiminine has been regarded as a traditional anti-fibrotic Chinese medicine in pulmonary fibrosis. However, the role of peiminine in myocardial infarction-induced myocardial injury and fibrosis remained elusive. Firstly, rat model of myocardial infarction was established using ligation of the left coronary artery, which were then intraperitoneally injected with 2 or 5 mg/kg peiminine once a day for 4 weeks. Echocardiography and haemodynamic evaluation results showed that peiminine treatment reduced left ventricular end-diastolic pressure, and enhanced maximum rate of increase/decrease of left ventricle pressure (± dP/dt max) and left ventricular systolic pressure, which ameliorate the cardiac function. Secondly, myocardial infarction-induced myocardial injury and infarct size were also attenuated by peiminine. Moreover, peiminine inhibited myocardial infarction-induced increase of interleukin (IL)-1β, IL-6 and tumor necrosis factor-α production, as well as the myocardial cell apoptosis, in the rats. Thirdly, peiminine also decreased the myocardial fibrosis related protein expression including collagen I and collagen III. Lastly, peiminine reduced the expression of p38 and phosphorylation of extracellular signal-regulated kinase 1/2 in rat model of myocardial infarction. In conclusion, peiminine has a cardioprotective effect against myocardial infarction-induced myocardial injury and fibrosis, which can be attributed to the inactivation of mitogen-activated protein kinase pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제4권6호
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• pp.515-523
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• 2000

Polymorphonuclear leukocytes (PMNs) play an important role in myocardial ischemia/reperfusion (MI/R) injury. Moreover, platelets are also important blood cells that can aggravate myocardial ischemic injury. This study was designed to test the effects of PMNs and platelets separately and together in provoking cardiac dysfunction in isolated perfused rat hearts following ischemia and reperfusion. Additional control rat hearts were perfused with $75{\times}10^6$ PMNs, with $75{\times}10^6$ platelets, or with $75{\times}10^6\;PMNs+75{\times}10^6$ platelets over a five minute perfusion followed by a 75 min observation period. No significant reduction in coronary flow (CF), left ventricular developed pressure (LVDP), or the first derivative of LVDP (dP/dt max) was observed at the end of the observation period in any non-ischemic group. Similarly, global ischemia (I) for 20 min followed by 45 minutes of reperfusion (R) produced no sustained effects on the final recovery of any of these parameters in any group of hearts perfused in the absence of blood cells. However, I/R hearts perfused with either PMNs or platelets alone exhibited decreases in these variables of $5{\sim}10%$ (p＜0.05 from control). Furthermore, I/R hearts perfused with both PMNs and platelets exhibited decreases of 50 to 60% in all measurements of cardiac function (p＜0.01). These dual cell perfused I/R hearts also exhibited marked increases in cardiac myeloperoxidase (MPO) activity indicating a significant PMN infiltration, and enhanced P-selectin expression on the coronary microvascular endothelium. All cardiaodynamic effects as well as PMN accumulation and P-selectin expression were markedly attenuated by a recombinant soluble PSGL-1 which inhibits selectin mediated cell adhesion. These results provide evidence that platelets and PMNs act synergistically in provoking post-reperfusion cardiac dysfunction, and that this may be largely due to cell to cell interactions mediated by P-selectin. These results also demonstrate that a recombinant soluble PSGL-1 reduces myocardial reperfusion injury by platelet and PMNs interaction.